vendor/clang/clang-release_350-r216957

39 files changed, 17681 insertions, 1908 deletions

diff --git a/lib/Frontend/ASTConsumers.cpp b/lib/Frontend/ASTConsumers.cpp
index 1ef4c1868112..54a6d474c18a 100644
--- a/lib/Frontend/ASTConsumers.cpp
+++ b/lib/Frontend/ASTConsumers.cpp
@@ -36,12 +36,12 @@ namespace {
     typedef RecursiveASTVisitor<ASTPrinter> base;
 
   public:
-    ASTPrinter(raw_ostream *Out = NULL, bool Dump = false,
+    ASTPrinter(raw_ostream *Out = nullptr, bool Dump = false,
                StringRef FilterString = "", bool DumpLookups = false)
         : Out(Out ? *Out : llvm::outs()), Dump(Dump),
           FilterString(FilterString), DumpLookups(DumpLookups) {}
 
-    virtual void HandleTranslationUnit(ASTContext &Context) {
+    void HandleTranslationUnit(ASTContext &Context) override {
       TranslationUnitDecl *D = Context.getTranslationUnitDecl();
 
       if (FilterString.empty())
@@ -53,7 +53,7 @@ namespace {
     bool shouldWalkTypesOfTypeLocs() const { return false; }
 
     bool TraverseDecl(Decl *D) {
-      if (D != NULL && filterMatches(D)) {
+      if (D && filterMatches(D)) {
         bool ShowColors = Out.has_colors();
         if (ShowColors)
           Out.changeColor(raw_ostream::BLUE);
@@ -98,16 +98,16 @@ namespace {
   class ASTDeclNodeLister : public ASTConsumer,
                      public RecursiveASTVisitor<ASTDeclNodeLister> {
   public:
-    ASTDeclNodeLister(raw_ostream *Out = NULL)
+    ASTDeclNodeLister(raw_ostream *Out = nullptr)
         : Out(Out ? *Out : llvm::outs()) {}
 
-    virtual void HandleTranslationUnit(ASTContext &Context) {
+    void HandleTranslationUnit(ASTContext &Context) override {
       TraverseDecl(Context.getTranslationUnitDecl());
     }
 
     bool shouldWalkTypesOfTypeLocs() const { return false; }
 
-    virtual bool VisitNamedDecl(NamedDecl *D) {
+    bool VisitNamedDecl(NamedDecl *D) {
       D->printQualifiedName(Out);
       Out << '\n';
       return true;
@@ -124,11 +124,11 @@ ASTConsumer *clang::CreateASTPrinter(raw_ostream *Out,
 }
 
 ASTConsumer *clang::CreateASTDumper(StringRef FilterString, bool DumpLookups) {
-  return new ASTPrinter(0, /*Dump=*/ true, FilterString, DumpLookups);
+  return new ASTPrinter(nullptr, /*Dump=*/true, FilterString, DumpLookups);
 }
 
 ASTConsumer *clang::CreateASTDeclNodeLister() {
-  return new ASTDeclNodeLister(0);
+  return new ASTDeclNodeLister(nullptr);
 }
 
 //===----------------------------------------------------------------------===//
@@ -138,11 +138,11 @@ namespace {
   class ASTViewer : public ASTConsumer {
     ASTContext *Context;
   public:
-    void Initialize(ASTContext &Context) {
+    void Initialize(ASTContext &Context) override {
       this->Context = &Context;
     }
 
-    virtual bool HandleTopLevelDecl(DeclGroupRef D) {
+    bool HandleTopLevelDecl(DeclGroupRef D) override {
       for (DeclGroupRef::iterator I = D.begin(), E = D.end(); I != E; ++I)
         HandleTopLevelSingleDecl(*I);
       return true;
@@ -177,7 +177,7 @@ class DeclContextPrinter : public ASTConsumer {
 public:
   DeclContextPrinter() : Out(llvm::errs()) {}
 
-  void HandleTranslationUnit(ASTContext &C) {
+  void HandleTranslationUnit(ASTContext &C) override {
     PrintDeclContext(C.getTranslationUnitDecl(), 4);
   }
 
@@ -259,13 +259,12 @@ void DeclContextPrinter::PrintDeclContext(const DeclContext* DC,
     // Print the parameters.
     Out << "(";
     bool PrintComma = false;
-    for (FunctionDecl::param_const_iterator I = FD->param_begin(),
-           E = FD->param_end(); I != E; ++I) {
+    for (auto I : FD->params()) {
       if (PrintComma)
         Out << ", ";
       else
         PrintComma = true;
-      Out << **I;
+      Out << *I;
     }
     Out << ")";
     break;
@@ -369,8 +368,7 @@ void DeclContextPrinter::PrintDeclContext(const DeclContext* DC,
   Out << "\n";
 
   // Print decls in the DeclContext.
-  for (DeclContext::decl_iterator I = DC->decls_begin(), E = DC->decls_end();
-       I != E; ++I) {
+  for (auto *I : DC->decls()) {
     for (unsigned i = 0; i < Indentation; ++i)
       Out << "  ";
 
@@ -394,58 +392,58 @@ void DeclContextPrinter::PrintDeclContext(const DeclContext* DC,
     case Decl::CXXDestructor:
     case Decl::CXXConversion:
     {
-      DeclContext* DC = cast<DeclContext>(*I);
+      DeclContext* DC = cast<DeclContext>(I);
       PrintDeclContext(DC, Indentation+2);
       break;
     }
     case Decl::IndirectField: {
-      IndirectFieldDecl* IFD = cast<IndirectFieldDecl>(*I);
+      IndirectFieldDecl* IFD = cast<IndirectFieldDecl>(I);
       Out << "<IndirectField> " << *IFD << '\n';
       break;
     }
     case Decl::Label: {
-      LabelDecl *LD = cast<LabelDecl>(*I);
+      LabelDecl *LD = cast<LabelDecl>(I);
       Out << "<Label> " << *LD << '\n';
       break;
     }
     case Decl::Field: {
-      FieldDecl *FD = cast<FieldDecl>(*I);
+      FieldDecl *FD = cast<FieldDecl>(I);
       Out << "<field> " << *FD << '\n';
       break;
     }
     case Decl::Typedef:
     case Decl::TypeAlias: {
-      TypedefNameDecl* TD = cast<TypedefNameDecl>(*I);
+      TypedefNameDecl* TD = cast<TypedefNameDecl>(I);
       Out << "<typedef> " << *TD << '\n';
       break;
     }
     case Decl::EnumConstant: {
-      EnumConstantDecl* ECD = cast<EnumConstantDecl>(*I);
+      EnumConstantDecl* ECD = cast<EnumConstantDecl>(I);
       Out << "<enum constant> " << *ECD << '\n';
       break;
     }
     case Decl::Var: {
-      VarDecl* VD = cast<VarDecl>(*I);
+      VarDecl* VD = cast<VarDecl>(I);
       Out << "<var> " << *VD << '\n';
       break;
     }
     case Decl::ImplicitParam: {
-      ImplicitParamDecl* IPD = cast<ImplicitParamDecl>(*I);
+      ImplicitParamDecl* IPD = cast<ImplicitParamDecl>(I);
       Out << "<implicit parameter> " << *IPD << '\n';
       break;
     }
     case Decl::ParmVar: {
-      ParmVarDecl* PVD = cast<ParmVarDecl>(*I);
+      ParmVarDecl* PVD = cast<ParmVarDecl>(I);
       Out << "<parameter> " << *PVD << '\n';
       break;
     }
     case Decl::ObjCProperty: {
-      ObjCPropertyDecl* OPD = cast<ObjCPropertyDecl>(*I);
+      ObjCPropertyDecl* OPD = cast<ObjCPropertyDecl>(I);
       Out << "<objc property> " << *OPD << '\n';
       break;
     }
     case Decl::FunctionTemplate: {
-      FunctionTemplateDecl* FTD = cast<FunctionTemplateDecl>(*I);
+      FunctionTemplateDecl* FTD = cast<FunctionTemplateDecl>(I);
       Out << "<function template> " << *FTD << '\n';
       break;
     }
@@ -458,21 +456,21 @@ void DeclContextPrinter::PrintDeclContext(const DeclContext* DC,
       break;
     }
     case Decl::NamespaceAlias: {
-      NamespaceAliasDecl* NAD = cast<NamespaceAliasDecl>(*I);
+      NamespaceAliasDecl* NAD = cast<NamespaceAliasDecl>(I);
       Out << "<namespace alias> " << *NAD << '\n';
       break;
     }
     case Decl::ClassTemplate: {
-      ClassTemplateDecl *CTD = cast<ClassTemplateDecl>(*I);
+      ClassTemplateDecl *CTD = cast<ClassTemplateDecl>(I);
       Out << "<class template> " << *CTD << '\n';
       break;
     }
     case Decl::OMPThreadPrivate: {
-      Out << "<omp threadprivate> " << '"' << *I << "\"\n";
+      Out << "<omp threadprivate> " << '"' << I << "\"\n";
       break;
     }
     default:
-      Out << "DeclKind: " << DK << '"' << *I << "\"\n";
+      Out << "DeclKind: " << DK << '"' << I << "\"\n";
       llvm_unreachable("decl unhandled");
     }
   }
diff --git a/lib/Frontend/ASTMerge.cpp b/lib/Frontend/ASTMerge.cpp
index b6c644eba783..ff6434c56945 100644
--- a/lib/Frontend/ASTMerge.cpp
+++ b/lib/Frontend/ASTMerge.cpp
@@ -57,16 +57,14 @@ void ASTMergeAction::ExecuteAction() {
                          /*MinimalImport=*/false);
 
     TranslationUnitDecl *TU = Unit->getASTContext().getTranslationUnitDecl();
-    for (DeclContext::decl_iterator D = TU->decls_begin(), 
-                                 DEnd = TU->decls_end();
-         D != DEnd; ++D) {
+    for (auto *D : TU->decls()) {
       // Don't re-import __va_list_tag, __builtin_va_list.
-      if (NamedDecl *ND = dyn_cast<NamedDecl>(*D))
+      if (const auto *ND = dyn_cast<NamedDecl>(D))
         if (IdentifierInfo *II = ND->getIdentifier())
           if (II->isStr("__va_list_tag") || II->isStr("__builtin_va_list"))
             continue;
       
-      Importer.Import(*D);
+      Importer.Import(D);
     }
 
     delete Unit;
diff --git a/lib/Frontend/ASTUnit.cpp b/lib/Frontend/ASTUnit.cpp
index a8c587638a28..fc44d9f1b4c0 100644
--- a/lib/Frontend/ASTUnit.cpp
+++ b/lib/Frontend/ASTUnit.cpp
@@ -20,6 +20,7 @@
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Basic/TargetOptions.h"
+#include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/FrontendActions.h"
 #include "clang/Frontend/FrontendDiagnostic.h"
@@ -35,9 +36,7 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringSet.h"
-#include "llvm/Support/Atomic.h"
 #include "llvm/Support/CrashRecoveryContext.h"
-#include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Mutex.h"
@@ -45,9 +44,9 @@
 #include "llvm/Support/Path.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/raw_ostream.h"
+#include <atomic>
 #include <cstdio>
 #include <cstdlib>
-#include <sys/stat.h>
 using namespace clang;
 
 using llvm::TimeRecord;
@@ -191,10 +190,7 @@ struct ASTUnit::ASTWriterData {
 };
 
 void ASTUnit::clearFileLevelDecls() {
-  for (FileDeclsTy::iterator
-         I = FileDecls.begin(), E = FileDecls.end(); I != E; ++I)
-    delete I->second;
-  FileDecls.clear();
+  llvm::DeleteContainerSeconds(FileDecls);
 }
 
 void ASTUnit::CleanTemporaryFiles() {
@@ -214,27 +210,25 @@ const unsigned DefaultPreambleRebuildInterval = 5;
 /// \brief Tracks the number of ASTUnit objects that are currently active.
 ///
 /// Used for debugging purposes only.
-static llvm::sys::cas_flag ActiveASTUnitObjects;
+static std::atomic<unsigned> ActiveASTUnitObjects;
 
 ASTUnit::ASTUnit(bool _MainFileIsAST)
-  : Reader(0), HadModuleLoaderFatalFailure(false),
+  : Reader(nullptr), HadModuleLoaderFatalFailure(false),
     OnlyLocalDecls(false), CaptureDiagnostics(false),
     MainFileIsAST(_MainFileIsAST), 
     TUKind(TU_Complete), WantTiming(getenv("LIBCLANG_TIMING")),
     OwnsRemappedFileBuffers(true),
     NumStoredDiagnosticsFromDriver(0),
-    PreambleRebuildCounter(0), SavedMainFileBuffer(0), PreambleBuffer(0),
-    NumWarningsInPreamble(0),
+    PreambleRebuildCounter(0), SavedMainFileBuffer(nullptr),
+    PreambleBuffer(nullptr), NumWarningsInPreamble(0),
     ShouldCacheCodeCompletionResults(false),
     IncludeBriefCommentsInCodeCompletion(false), UserFilesAreVolatile(false),
     CompletionCacheTopLevelHashValue(0),
     PreambleTopLevelHashValue(0),
     CurrentTopLevelHashValue(0),
     UnsafeToFree(false) { 
-  if (getenv("LIBCLANG_OBJTRACKING")) {
-    llvm::sys::AtomicIncrement(&ActiveASTUnitObjects);
-    fprintf(stderr, "+++ %d translation units\n", ActiveASTUnitObjects);
-  }    
+  if (getenv("LIBCLANG_OBJTRACKING"))
+    fprintf(stderr, "+++ %u translation units\n", ++ActiveASTUnitObjects);
 }
 
 ASTUnit::~ASTUnit() {
@@ -252,14 +246,10 @@ ASTUnit::~ASTUnit() {
   // perform this operation here because we explicitly request that the
   // compiler instance *not* free these buffers for each invocation of the
   // parser.
-  if (Invocation.getPtr() && OwnsRemappedFileBuffers) {
+  if (Invocation.get() && OwnsRemappedFileBuffers) {
     PreprocessorOptions &PPOpts = Invocation->getPreprocessorOpts();
-    for (PreprocessorOptions::remapped_file_buffer_iterator
-           FB = PPOpts.remapped_file_buffer_begin(),
-           FBEnd = PPOpts.remapped_file_buffer_end();
-         FB != FBEnd;
-         ++FB)
-      delete FB->second;
+    for (const auto &RB : PPOpts.RemappedFileBuffers)
+      delete RB.second;
   }
   
   delete SavedMainFileBuffer;
@@ -267,10 +257,8 @@ ASTUnit::~ASTUnit() {
 
   ClearCachedCompletionResults();  
   
-  if (getenv("LIBCLANG_OBJTRACKING")) {
-    llvm::sys::AtomicDecrement(&ActiveASTUnitObjects);
-    fprintf(stderr, "--- %d translation units\n", ActiveASTUnitObjects);
-  }    
+  if (getenv("LIBCLANG_OBJTRACKING"))
+    fprintf(stderr, "--- %u translation units\n", --ActiveASTUnitObjects);
 }
 
 void ASTUnit::setPreprocessor(Preprocessor *pp) { PP = pp; }
@@ -500,7 +488,7 @@ void ASTUnit::CacheCodeCompletionResults() {
 void ASTUnit::ClearCachedCompletionResults() {
   CachedCompletionResults.clear();
   CachedCompletionTypes.clear();
-  CachedCompletionAllocator = 0;
+  CachedCompletionAllocator = nullptr;
 }
 
 namespace {
@@ -511,23 +499,20 @@ class ASTInfoCollector : public ASTReaderListener {
   Preprocessor &PP;
   ASTContext &Context;
   LangOptions &LangOpt;
-  IntrusiveRefCntPtr<TargetOptions> &TargetOpts;
+  std::shared_ptr<TargetOptions> &TargetOpts;
   IntrusiveRefCntPtr<TargetInfo> &Target;
   unsigned &Counter;
 
   bool InitializedLanguage;
 public:
-  ASTInfoCollector(Preprocessor &PP, ASTContext &Context, LangOptions &LangOpt, 
-                   IntrusiveRefCntPtr<TargetOptions> &TargetOpts,
-                   IntrusiveRefCntPtr<TargetInfo> &Target,
-                   unsigned &Counter)
-    : PP(PP), Context(Context), LangOpt(LangOpt),
-      TargetOpts(TargetOpts), Target(Target),
-      Counter(Counter),
-      InitializedLanguage(false) {}
-
-  virtual bool ReadLanguageOptions(const LangOptions &LangOpts,
-                                   bool Complain) {
+  ASTInfoCollector(Preprocessor &PP, ASTContext &Context, LangOptions &LangOpt,
+                   std::shared_ptr<TargetOptions> &TargetOpts,
+                   IntrusiveRefCntPtr<TargetInfo> &Target, unsigned &Counter)
+      : PP(PP), Context(Context), LangOpt(LangOpt), TargetOpts(TargetOpts),
+        Target(Target), Counter(Counter), InitializedLanguage(false) {}
+
+  bool ReadLanguageOptions(const LangOptions &LangOpts,
+                           bool Complain) override {
     if (InitializedLanguage)
       return false;
     
@@ -538,21 +523,22 @@ public:
     return false;
   }
 
-  virtual bool ReadTargetOptions(const TargetOptions &TargetOpts,
-                                 bool Complain) {
+  bool ReadTargetOptions(const TargetOptions &TargetOpts,
+                         bool Complain) override {
     // If we've already initialized the target, don't do it again.
     if (Target)
       return false;
-    
-    this->TargetOpts = new TargetOptions(TargetOpts);
-    Target = TargetInfo::CreateTargetInfo(PP.getDiagnostics(),
-                                          &*this->TargetOpts);
+
+    this->TargetOpts = std::make_shared<TargetOptions>(TargetOpts);
+    Target =
+        TargetInfo::CreateTargetInfo(PP.getDiagnostics(), this->TargetOpts);
 
     updated();
     return false;
   }
 
-  virtual void ReadCounter(const serialization::ModuleFile &M, unsigned Value) {
+  void ReadCounter(const serialization::ModuleFile &M,
+                   unsigned Value) override {
     Counter = Value;
   }
 
@@ -565,7 +551,7 @@ private:
     //
     // FIXME: We shouldn't need to do this, the target should be immutable once
     // created. This complexity should be lifted elsewhere.
-    Target->setForcedLangOptions(LangOpt);
+    Target->adjust(LangOpt);
 
     // Initialize the preprocessor.
     PP.Initialize(*Target);
@@ -588,16 +574,16 @@ class StoredDiagnosticConsumer : public DiagnosticConsumer {
 public:
   explicit StoredDiagnosticConsumer(
                           SmallVectorImpl<StoredDiagnostic> &StoredDiags)
-    : StoredDiags(StoredDiags), SourceMgr(0) { }
+    : StoredDiags(StoredDiags), SourceMgr(nullptr) {}
 
-  virtual void BeginSourceFile(const LangOptions &LangOpts,
-                               const Preprocessor *PP = 0) {
+  void BeginSourceFile(const LangOptions &LangOpts,
+                       const Preprocessor *PP = nullptr) override {
     if (PP)
       SourceMgr = &PP->getSourceManager();
   }
 
-  virtual void HandleDiagnostic(DiagnosticsEngine::Level Level,
-                                const Diagnostic &Info);
+  void HandleDiagnostic(DiagnosticsEngine::Level Level,
+                        const Diagnostic &Info) override;
 };
 
 /// \brief RAII object that optionally captures diagnostics, if
@@ -610,9 +596,9 @@ class CaptureDroppedDiagnostics {
 public:
   CaptureDroppedDiagnostics(bool RequestCapture, DiagnosticsEngine &Diags,
                           SmallVectorImpl<StoredDiagnostic> &StoredDiags)
-    : Diags(Diags), Client(StoredDiags), PreviousClient(0)
+    : Diags(Diags), Client(StoredDiags), PreviousClient(nullptr)
   {
-    if (RequestCapture || Diags.getClient() == 0) {
+    if (RequestCapture || Diags.getClient() == nullptr) {
       PreviousClient = Diags.takeClient();
       Diags.setClient(&Client);
     }
@@ -643,13 +629,13 @@ void StoredDiagnosticConsumer::HandleDiagnostic(DiagnosticsEngine::Level Level,
 ASTMutationListener *ASTUnit::getASTMutationListener() {
   if (WriterData)
     return &WriterData->Writer;
-  return 0;
+  return nullptr;
 }
 
 ASTDeserializationListener *ASTUnit::getDeserializationListener() {
   if (WriterData)
     return &WriterData->Writer;
-  return 0;
+  return nullptr;
 }
 
 llvm::MemoryBuffer *ASTUnit::getBufferForFile(StringRef Filename,
@@ -662,10 +648,10 @@ llvm::MemoryBuffer *ASTUnit::getBufferForFile(StringRef Filename,
 void ASTUnit::ConfigureDiags(IntrusiveRefCntPtr<DiagnosticsEngine> &Diags,
                              const char **ArgBegin, const char **ArgEnd,
                              ASTUnit &AST, bool CaptureDiagnostics) {
-  if (!Diags.getPtr()) {
+  if (!Diags.get()) {
     // No diagnostics engine was provided, so create our own diagnostics object
     // with the default options.
-    DiagnosticConsumer *Client = 0;
+    DiagnosticConsumer *Client = nullptr;
     if (CaptureDiagnostics)
       Client = new StoredDiagnosticConsumer(AST.StoredDiagnostics);
     Diags = CompilerInstance::createDiagnostics(new DiagnosticOptions(),
@@ -680,129 +666,74 @@ ASTUnit *ASTUnit::LoadFromASTFile(const std::string &Filename,
                               IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
                                   const FileSystemOptions &FileSystemOpts,
                                   bool OnlyLocalDecls,
-                                  RemappedFile *RemappedFiles,
-                                  unsigned NumRemappedFiles,
+                                  ArrayRef<RemappedFile> RemappedFiles,
                                   bool CaptureDiagnostics,
                                   bool AllowPCHWithCompilerErrors,
                                   bool UserFilesAreVolatile) {
-  OwningPtr<ASTUnit> AST(new ASTUnit(true));
+  std::unique_ptr<ASTUnit> AST(new ASTUnit(true));
 
   // Recover resources if we crash before exiting this method.
   llvm::CrashRecoveryContextCleanupRegistrar<ASTUnit>
     ASTUnitCleanup(AST.get());
   llvm::CrashRecoveryContextCleanupRegistrar<DiagnosticsEngine,
     llvm::CrashRecoveryContextReleaseRefCleanup<DiagnosticsEngine> >
-    DiagCleanup(Diags.getPtr());
+    DiagCleanup(Diags.get());
 
-  ConfigureDiags(Diags, 0, 0, *AST, CaptureDiagnostics);
+  ConfigureDiags(Diags, nullptr, nullptr, *AST, CaptureDiagnostics);
 
   AST->OnlyLocalDecls = OnlyLocalDecls;
   AST->CaptureDiagnostics = CaptureDiagnostics;
   AST->Diagnostics = Diags;
-  AST->FileMgr = new FileManager(FileSystemOpts);
+  IntrusiveRefCntPtr<vfs::FileSystem> VFS = vfs::getRealFileSystem();
+  AST->FileMgr = new FileManager(FileSystemOpts, VFS);
   AST->UserFilesAreVolatile = UserFilesAreVolatile;
   AST->SourceMgr = new SourceManager(AST->getDiagnostics(),
                                      AST->getFileManager(),
                                      UserFilesAreVolatile);
   AST->HSOpts = new HeaderSearchOptions();
-  
+
   AST->HeaderInfo.reset(new HeaderSearch(AST->HSOpts,
                                          AST->getSourceManager(),
                                          AST->getDiagnostics(),
                                          AST->ASTFileLangOpts,
-                                         /*Target=*/0));
-  
-  for (unsigned I = 0; I != NumRemappedFiles; ++I) {
-    FilenameOrMemBuf fileOrBuf = RemappedFiles[I].second;
-    if (const llvm::MemoryBuffer *
-          memBuf = fileOrBuf.dyn_cast<const llvm::MemoryBuffer *>()) {
-      // Create the file entry for the file that we're mapping from.
-      const FileEntry *FromFile
-        = AST->getFileManager().getVirtualFile(RemappedFiles[I].first,
-                                               memBuf->getBufferSize(),
-                                               0);
-      if (!FromFile) {
-        AST->getDiagnostics().Report(diag::err_fe_remap_missing_from_file)
-          << RemappedFiles[I].first;
-        delete memBuf;
-        continue;
-      }
-      
-      // Override the contents of the "from" file with the contents of
-      // the "to" file.
-      AST->getSourceManager().overrideFileContents(FromFile, memBuf);
+                                         /*Target=*/nullptr));
 
-    } else {
-      const char *fname = fileOrBuf.get<const char *>();
-      const FileEntry *ToFile = AST->FileMgr->getFile(fname);
-      if (!ToFile) {
-        AST->getDiagnostics().Report(diag::err_fe_remap_missing_to_file)
-        << RemappedFiles[I].first << fname;
-        continue;
-      }
+  PreprocessorOptions *PPOpts = new PreprocessorOptions();
+
+  for (unsigned I = 0, N = RemappedFiles.size(); I != N; ++I)
+    PPOpts->addRemappedFile(RemappedFiles[I].first, RemappedFiles[I].second);
 
-      // Create the file entry for the file that we're mapping from.
-      const FileEntry *FromFile
-        = AST->getFileManager().getVirtualFile(RemappedFiles[I].first,
-                                               ToFile->getSize(),
-                                               0);
-      if (!FromFile) {
-        AST->getDiagnostics().Report(diag::err_fe_remap_missing_from_file)
-          << RemappedFiles[I].first;
-        delete memBuf;
-        continue;
-      }
-      
-      // Override the contents of the "from" file with the contents of
-      // the "to" file.
-      AST->getSourceManager().overrideFileContents(FromFile, ToFile);
-    }
-  }
-  
   // Gather Info for preprocessor construction later on.
 
   HeaderSearch &HeaderInfo = *AST->HeaderInfo.get();
   unsigned Counter;
 
-  OwningPtr<ASTReader> Reader;
-
-  AST->PP = new Preprocessor(new PreprocessorOptions(),
-                             AST->getDiagnostics(), AST->ASTFileLangOpts,
-                             /*Target=*/0, AST->getSourceManager(), HeaderInfo, 
-                             *AST, 
-                             /*IILookup=*/0,
-                             /*OwnsHeaderSearch=*/false,
-                             /*DelayInitialization=*/true);
+  AST->PP =
+      new Preprocessor(PPOpts, AST->getDiagnostics(), AST->ASTFileLangOpts,
+                       AST->getSourceManager(), HeaderInfo, *AST,
+                       /*IILookup=*/nullptr,
+                       /*OwnsHeaderSearch=*/false);
   Preprocessor &PP = *AST->PP;
 
-  AST->Ctx = new ASTContext(AST->ASTFileLangOpts,
-                            AST->getSourceManager(),
-                            /*Target=*/0,
-                            PP.getIdentifierTable(),
-                            PP.getSelectorTable(),
-                            PP.getBuiltinInfo(),
-                            /* size_reserve = */0,
-                            /*DelayInitialization=*/true);
+  AST->Ctx = new ASTContext(AST->ASTFileLangOpts, AST->getSourceManager(),
+                            PP.getIdentifierTable(), PP.getSelectorTable(),
+                            PP.getBuiltinInfo());
   ASTContext &Context = *AST->Ctx;
 
   bool disableValid = false;
   if (::getenv("LIBCLANG_DISABLE_PCH_VALIDATION"))
     disableValid = true;
-  Reader.reset(new ASTReader(PP, Context,
+  AST->Reader = new ASTReader(PP, Context,
                              /*isysroot=*/"",
                              /*DisableValidation=*/disableValid,
-                             AllowPCHWithCompilerErrors));
-  
-  // Recover resources if we crash before exiting this method.
-  llvm::CrashRecoveryContextCleanupRegistrar<ASTReader>
-    ReaderCleanup(Reader.get());
+                             AllowPCHWithCompilerErrors);
 
-  Reader->setListener(new ASTInfoCollector(*AST->PP, Context,
+  AST->Reader->setListener(new ASTInfoCollector(*AST->PP, Context,
                                            AST->ASTFileLangOpts,
                                            AST->TargetOpts, AST->Target, 
                                            Counter));
 
-  switch (Reader->ReadAST(Filename, serialization::MK_MainFile,
+  switch (AST->Reader->ReadAST(Filename, serialization::MK_MainFile,
                           SourceLocation(), ASTReader::ARR_None)) {
   case ASTReader::Success:
     break;
@@ -814,24 +745,17 @@ ASTUnit *ASTUnit::LoadFromASTFile(const std::string &Filename,
   case ASTReader::ConfigurationMismatch:
   case ASTReader::HadErrors:
     AST->getDiagnostics().Report(diag::err_fe_unable_to_load_pch);
-    return NULL;
+    return nullptr;
   }
 
-  AST->OriginalSourceFile = Reader->getOriginalSourceFile();
+  AST->OriginalSourceFile = AST->Reader->getOriginalSourceFile();
 
   PP.setCounterValue(Counter);
 
   // Attach the AST reader to the AST context as an external AST
   // source, so that declarations will be deserialized from the
   // AST file as needed.
-  ASTReader *ReaderPtr = Reader.get();
-  OwningPtr<ExternalASTSource> Source(Reader.take());
-
-  // Unregister the cleanup for ASTReader.  It will get cleaned up
-  // by the ASTUnit cleanup.
-  ReaderCleanup.unregister();
-
-  Context.setExternalSource(Source);
+  Context.setExternalSource(AST->Reader);
 
   // Create an AST consumer, even though it isn't used.
   AST->Consumer.reset(new ASTConsumer);
@@ -839,13 +763,12 @@ ASTUnit *ASTUnit::LoadFromASTFile(const std::string &Filename,
   // Create a semantic analysis object and tell the AST reader about it.
   AST->TheSema.reset(new Sema(PP, Context, *AST->Consumer));
   AST->TheSema->Initialize();
-  ReaderPtr->InitializeSema(*AST->TheSema);
-  AST->Reader = ReaderPtr;
+  AST->Reader->InitializeSema(*AST->TheSema);
 
   // Tell the diagnostic client that we have started a source file.
   AST->getDiagnostics().getClient()->BeginSourceFile(Context.getLangOpts(),&PP);
 
-  return AST.take();
+  return AST.release();
 }
 
 namespace {
@@ -857,9 +780,9 @@ class MacroDefinitionTrackerPPCallbacks : public PPCallbacks {
   
 public:
   explicit MacroDefinitionTrackerPPCallbacks(unsigned &Hash) : Hash(Hash) { }
-  
-  virtual void MacroDefined(const Token &MacroNameTok,
-                            const MacroDirective *MD) {
+
+  void MacroDefined(const Token &MacroNameTok,
+                    const MacroDirective *MD) override {
     Hash = llvm::HashString(MacroNameTok.getIdentifierInfo()->getName(), Hash);
   }
 };
@@ -881,10 +804,9 @@ void AddTopLevelDeclarationToHash(Decl *D, unsigned &Hash) {
       // For an unscoped enum include the enumerators in the hash since they
       // enter the top-level namespace.
       if (!EnumD->isScoped()) {
-        for (EnumDecl::enumerator_iterator EI = EnumD->enumerator_begin(),
-               EE = EnumD->enumerator_end(); EI != EE; ++EI) {
-          if ((*EI)->getIdentifier())
-            Hash = llvm::HashString((*EI)->getIdentifier()->getName(), Hash);
+        for (const auto *EI : EnumD->enumerators()) {
+          if (EI->getIdentifier())
+            Hash = llvm::HashString(EI->getIdentifier()->getName(), Hash);
         }
       }
     }
@@ -937,31 +859,30 @@ public:
   void handleFileLevelDecl(Decl *D) {
     Unit.addFileLevelDecl(D);
     if (NamespaceDecl *NSD = dyn_cast<NamespaceDecl>(D)) {
-      for (NamespaceDecl::decl_iterator
-             I = NSD->decls_begin(), E = NSD->decls_end(); I != E; ++I)
-        handleFileLevelDecl(*I);
+      for (auto *I : NSD->decls())
+        handleFileLevelDecl(I);
     }
   }
 
-  bool HandleTopLevelDecl(DeclGroupRef D) {
+  bool HandleTopLevelDecl(DeclGroupRef D) override {
     for (DeclGroupRef::iterator it = D.begin(), ie = D.end(); it != ie; ++it)
       handleTopLevelDecl(*it);
     return true;
   }
 
   // We're not interested in "interesting" decls.
-  void HandleInterestingDecl(DeclGroupRef) {}
+  void HandleInterestingDecl(DeclGroupRef) override {}
 
-  void HandleTopLevelDeclInObjCContainer(DeclGroupRef D) {
+  void HandleTopLevelDeclInObjCContainer(DeclGroupRef D) override {
     for (DeclGroupRef::iterator it = D.begin(), ie = D.end(); it != ie; ++it)
       handleTopLevelDecl(*it);
   }
 
-  virtual ASTMutationListener *GetASTMutationListener() {
+  ASTMutationListener *GetASTMutationListener() override {
     return Unit.getASTMutationListener();
   }
 
-  virtual ASTDeserializationListener *GetASTDeserializationListener() {
+  ASTDeserializationListener *GetASTDeserializationListener() override {
     return Unit.getDeserializationListener();
   }
 };
@@ -970,8 +891,8 @@ class TopLevelDeclTrackerAction : public ASTFrontendAction {
 public:
   ASTUnit &Unit;
 
-  virtual ASTConsumer *CreateASTConsumer(CompilerInstance &CI,
-                                         StringRef InFile) {
+  ASTConsumer *CreateASTConsumer(CompilerInstance &CI,
+                                 StringRef InFile) override {
     CI.getPreprocessor().addPPCallbacks(
      new MacroDefinitionTrackerPPCallbacks(Unit.getCurrentTopLevelHashValue()));
     return new TopLevelDeclTrackerConsumer(Unit, 
@@ -981,8 +902,8 @@ public:
 public:
   TopLevelDeclTrackerAction(ASTUnit &_Unit) : Unit(_Unit) {}
 
-  virtual bool hasCodeCompletionSupport() const { return false; }
-  virtual TranslationUnitKind getTranslationUnitKind()  { 
+  bool hasCodeCompletionSupport() const override { return false; }
+  TranslationUnitKind getTranslationUnitKind() override {
     return Unit.getTranslationUnitKind(); 
   }
 };
@@ -995,15 +916,15 @@ public:
   explicit PrecompilePreambleAction(ASTUnit &Unit)
       : Unit(Unit), HasEmittedPreamblePCH(false) {}
 
-  virtual ASTConsumer *CreateASTConsumer(CompilerInstance &CI,
-                                         StringRef InFile);
+  ASTConsumer *CreateASTConsumer(CompilerInstance &CI,
+                                 StringRef InFile) override;
   bool hasEmittedPreamblePCH() const { return HasEmittedPreamblePCH; }
   void setHasEmittedPreamblePCH() { HasEmittedPreamblePCH = true; }
-  virtual bool shouldEraseOutputFiles() { return !hasEmittedPreamblePCH(); }
+  bool shouldEraseOutputFiles() override { return !hasEmittedPreamblePCH(); }
 
-  virtual bool hasCodeCompletionSupport() const { return false; }
-  virtual bool hasASTFileSupport() const { return false; }
-  virtual TranslationUnitKind getTranslationUnitKind() { return TU_Prefix; }
+  bool hasCodeCompletionSupport() const override { return false; }
+  bool hasASTFileSupport() const override { return false; }
+  TranslationUnitKind getTranslationUnitKind() override { return TU_Prefix; }
 };
 
 class PrecompilePreambleConsumer : public PCHGenerator {
@@ -1016,12 +937,12 @@ public:
   PrecompilePreambleConsumer(ASTUnit &Unit, PrecompilePreambleAction *Action,
                              const Preprocessor &PP, StringRef isysroot,
                              raw_ostream *Out)
-    : PCHGenerator(PP, "", 0, isysroot, Out, /*AllowASTWithErrors=*/true),
+    : PCHGenerator(PP, "", nullptr, isysroot, Out, /*AllowASTWithErrors=*/true),
       Unit(Unit), Hash(Unit.getCurrentTopLevelHashValue()), Action(Action) {
     Hash = 0;
   }
 
-  virtual bool HandleTopLevelDecl(DeclGroupRef D) {
+  bool HandleTopLevelDecl(DeclGroupRef D) override {
     for (DeclGroupRef::iterator it = D.begin(), ie = D.end(); it != ie; ++it) {
       Decl *D = *it;
       // FIXME: Currently ObjC method declarations are incorrectly being
@@ -1036,7 +957,7 @@ public:
     return true;
   }
 
-  virtual void HandleTranslationUnit(ASTContext &Ctx) {
+  void HandleTranslationUnit(ASTContext &Ctx) override {
     PCHGenerator::HandleTranslationUnit(Ctx);
     if (hasEmittedPCH()) {
       // Translate the top-level declarations we captured during
@@ -1062,10 +983,10 @@ ASTConsumer *PrecompilePreambleAction::CreateASTConsumer(CompilerInstance &CI,
                                                          StringRef InFile) {
   std::string Sysroot;
   std::string OutputFile;
-  raw_ostream *OS = 0;
+  raw_ostream *OS = nullptr;
   if (GeneratePCHAction::ComputeASTConsumerArguments(CI, InFile, Sysroot,
                                                      OutputFile, OS))
-    return 0;
+    return nullptr;
 
   if (!CI.getFrontendOpts().RelocatablePCH)
     Sysroot.clear();
@@ -1112,15 +1033,15 @@ static void checkAndSanitizeDiags(SmallVectorImpl<StoredDiagnostic> &
 /// contain any translation-unit information, false otherwise.
 bool ASTUnit::Parse(llvm::MemoryBuffer *OverrideMainBuffer) {
   delete SavedMainFileBuffer;
-  SavedMainFileBuffer = 0;
-  
+  SavedMainFileBuffer = nullptr;
+
   if (!Invocation) {
     delete OverrideMainBuffer;
     return true;
   }
   
   // Create the compiler instance to use for building the AST.
-  OwningPtr<CompilerInstance> Clang(new CompilerInstance());
+  std::unique_ptr<CompilerInstance> Clang(new CompilerInstance());
 
   // Recover resources if we crash before exiting this method.
   llvm::CrashRecoveryContextCleanupRegistrar<CompilerInstance>
@@ -1129,7 +1050,7 @@ bool ASTUnit::Parse(llvm::MemoryBuffer *OverrideMainBuffer) {
   IntrusiveRefCntPtr<CompilerInvocation>
     CCInvocation(new CompilerInvocation(*Invocation));
 
-  Clang->setInvocation(CCInvocation.getPtr());
+  Clang->setInvocation(CCInvocation.get());
   OriginalSourceFile = Clang->getFrontendOpts().Inputs[0].getFile();
     
   // Set up diagnostics, capturing any diagnostics that would
@@ -1137,8 +1058,8 @@ bool ASTUnit::Parse(llvm::MemoryBuffer *OverrideMainBuffer) {
   Clang->setDiagnostics(&getDiagnostics());
   
   // Create the target instance.
-  Clang->setTarget(TargetInfo::CreateTargetInfo(Clang->getDiagnostics(),
-                   &Clang->getTargetOpts()));
+  Clang->setTarget(TargetInfo::CreateTargetInfo(
+      Clang->getDiagnostics(), Clang->getInvocation().TargetOpts));
   if (!Clang->hasTarget()) {
     delete OverrideMainBuffer;
     return true;
@@ -1148,7 +1069,7 @@ bool ASTUnit::Parse(llvm::MemoryBuffer *OverrideMainBuffer) {
   //
   // FIXME: We shouldn't need to do this, the target should be immutable once
   // created. This complexity should be lifted elsewhere.
-  Clang->getTarget().setForcedLangOptions(Clang->getLangOpts());
+  Clang->getTarget().adjust(Clang->getLangOpts());
   
   assert(Clang->getFrontendOpts().Inputs.size() == 1 &&
          "Invocation must have exactly one source file!");
@@ -1158,17 +1079,22 @@ bool ASTUnit::Parse(llvm::MemoryBuffer *OverrideMainBuffer) {
          "IR inputs not support here!");
 
   // Configure the various subsystems.
-  // FIXME: Should we retain the previous file manager?
-  LangOpts = &Clang->getLangOpts();
+  LangOpts = Clang->getInvocation().LangOpts;
   FileSystemOpts = Clang->getFileSystemOpts();
-  FileMgr = new FileManager(FileSystemOpts);
+  IntrusiveRefCntPtr<vfs::FileSystem> VFS =
+      createVFSFromCompilerInvocation(Clang->getInvocation(), getDiagnostics());
+  if (!VFS) {
+    delete OverrideMainBuffer;
+    return true;
+  }
+  FileMgr = new FileManager(FileSystemOpts, VFS);
   SourceMgr = new SourceManager(getDiagnostics(), *FileMgr,
                                 UserFilesAreVolatile);
   TheSema.reset();
-  Ctx = 0;
-  PP = 0;
-  Reader = 0;
-  
+  Ctx = nullptr;
+  PP = nullptr;
+  Reader = nullptr;
+
   // Clear out old caches and data.
   TopLevelDecls.clear();
   clearFileLevelDecls();
@@ -1206,10 +1132,10 @@ bool ASTUnit::Parse(llvm::MemoryBuffer *OverrideMainBuffer) {
     // Keep track of the override buffer;
     SavedMainFileBuffer = OverrideMainBuffer;
   }
-  
-  OwningPtr<TopLevelDeclTrackerAction> Act(
-    new TopLevelDeclTrackerAction(*this));
-    
+
+  std::unique_ptr<TopLevelDeclTrackerAction> Act(
+      new TopLevelDeclTrackerAction(*this));
+
   // Recover resources if we crash before exiting this method.
   llvm::CrashRecoveryContextCleanupRegistrar<TopLevelDeclTrackerAction>
     ActCleanup(Act.get());
@@ -1219,9 +1145,8 @@ bool ASTUnit::Parse(llvm::MemoryBuffer *OverrideMainBuffer) {
 
   if (OverrideMainBuffer) {
     std::string ModName = getPreambleFile(this);
-    TranslateStoredDiagnostics(Clang->getModuleManager(), ModName,
-                               getSourceManager(), PreambleDiagnostics,
-                               StoredDiagnostics);
+    TranslateStoredDiagnostics(getFileManager(), getSourceManager(),
+                               PreambleDiagnostics, StoredDiagnostics);
   }
 
   if (!Act->Execute())
@@ -1239,7 +1164,7 @@ error:
   // Remove the overridden buffer we used for the preamble.
   if (OverrideMainBuffer) {
     delete OverrideMainBuffer;
-    SavedMainFileBuffer = 0;
+    SavedMainFileBuffer = nullptr;
   }
 
   // Keep the ownership of the data in the ASTUnit because the client may
@@ -1279,17 +1204,13 @@ ASTUnit::ComputePreamble(CompilerInvocation &Invocation,
   // Try to determine if the main file has been remapped, either from the 
   // command line (to another file) or directly through the compiler invocation
   // (to a memory buffer).
-  llvm::MemoryBuffer *Buffer = 0;
+  llvm::MemoryBuffer *Buffer = nullptr;
   std::string MainFilePath(FrontendOpts.Inputs[0].getFile());
   llvm::sys::fs::UniqueID MainFileID;
   if (!llvm::sys::fs::getUniqueID(MainFilePath, MainFileID)) {
     // Check whether there is a file-file remapping of the main file
-    for (PreprocessorOptions::remapped_file_iterator
-          M = PreprocessorOpts.remapped_file_begin(),
-          E = PreprocessorOpts.remapped_file_end();
-         M != E;
-         ++M) {
-      std::string MPath(M->first);
+    for (const auto &RF : PreprocessorOpts.RemappedFiles) {
+      std::string MPath(RF.first);
       llvm::sys::fs::UniqueID MID;
       if (!llvm::sys::fs::getUniqueID(MPath, MID)) {
         if (MainFileID == MID) {
@@ -1298,11 +1219,10 @@ ASTUnit::ComputePreamble(CompilerInvocation &Invocation,
             delete Buffer;
             CreatedBuffer = false;
           }
-          
-          Buffer = getBufferForFile(M->second);
+
+          Buffer = getBufferForFile(RF.second);
           if (!Buffer)
-            return std::make_pair((llvm::MemoryBuffer*)0, 
-                                  std::make_pair(0, true));
+            return std::make_pair(nullptr, std::make_pair(0, true));
           CreatedBuffer = true;
         }
       }
@@ -1310,12 +1230,8 @@ ASTUnit::ComputePreamble(CompilerInvocation &Invocation,
     
     // Check whether there is a file-buffer remapping. It supercedes the
     // file-file remapping.
-    for (PreprocessorOptions::remapped_file_buffer_iterator
-           M = PreprocessorOpts.remapped_file_buffer_begin(),
-           E = PreprocessorOpts.remapped_file_buffer_end();
-         M != E;
-         ++M) {
-      std::string MPath(M->first);
+    for (const auto &RB : PreprocessorOpts.RemappedFileBuffers) {
+      std::string MPath(RB.first);
       llvm::sys::fs::UniqueID MID;
       if (!llvm::sys::fs::getUniqueID(MPath, MID)) {
         if (MainFileID == MID) {
@@ -1324,8 +1240,8 @@ ASTUnit::ComputePreamble(CompilerInvocation &Invocation,
             delete Buffer;
             CreatedBuffer = false;
           }
-          
-          Buffer = const_cast<llvm::MemoryBuffer *>(M->second);
+
+          Buffer = const_cast<llvm::MemoryBuffer *>(RB.second);
         }
       }
     }
@@ -1335,8 +1251,8 @@ ASTUnit::ComputePreamble(CompilerInvocation &Invocation,
   if (!Buffer) {
     Buffer = getBufferForFile(FrontendOpts.Inputs[0].getFile());
     if (!Buffer)
-      return std::make_pair((llvm::MemoryBuffer*)0, std::make_pair(0, true));    
-    
+      return std::make_pair(nullptr, std::make_pair(0, true));
+
     CreatedBuffer = true;
   }
   
@@ -1345,20 +1261,83 @@ ASTUnit::ComputePreamble(CompilerInvocation &Invocation,
                                                        MaxLines));
 }
 
-static llvm::MemoryBuffer *CreatePaddedMainFileBuffer(llvm::MemoryBuffer *Old,
-                                                      unsigned NewSize,
-                                                      StringRef NewName) {
-  llvm::MemoryBuffer *Result
-    = llvm::MemoryBuffer::getNewUninitMemBuffer(NewSize, NewName);
-  memcpy(const_cast<char*>(Result->getBufferStart()), 
-         Old->getBufferStart(), Old->getBufferSize());
-  memset(const_cast<char*>(Result->getBufferStart()) + Old->getBufferSize(), 
-         ' ', NewSize - Old->getBufferSize() - 1);
-  const_cast<char*>(Result->getBufferEnd())[-1] = '\n';  
-  
+ASTUnit::PreambleFileHash
+ASTUnit::PreambleFileHash::createForFile(off_t Size, time_t ModTime) {
+  PreambleFileHash Result;
+  Result.Size = Size;
+  Result.ModTime = ModTime;
+  memset(Result.MD5, 0, sizeof(Result.MD5));
+  return Result;
+}
+
+ASTUnit::PreambleFileHash ASTUnit::PreambleFileHash::createForMemoryBuffer(
+    const llvm::MemoryBuffer *Buffer) {
+  PreambleFileHash Result;
+  Result.Size = Buffer->getBufferSize();
+  Result.ModTime = 0;
+
+  llvm::MD5 MD5Ctx;
+  MD5Ctx.update(Buffer->getBuffer().data());
+  MD5Ctx.final(Result.MD5);
+
   return Result;
 }
 
+namespace clang {
+bool operator==(const ASTUnit::PreambleFileHash &LHS,
+                const ASTUnit::PreambleFileHash &RHS) {
+  return LHS.Size == RHS.Size && LHS.ModTime == RHS.ModTime &&
+         memcmp(LHS.MD5, RHS.MD5, sizeof(LHS.MD5)) == 0;
+}
+} // namespace clang
+
+static std::pair<unsigned, unsigned>
+makeStandaloneRange(CharSourceRange Range, const SourceManager &SM,
+                    const LangOptions &LangOpts) {
+  CharSourceRange FileRange = Lexer::makeFileCharRange(Range, SM, LangOpts);
+  unsigned Offset = SM.getFileOffset(FileRange.getBegin());
+  unsigned EndOffset = SM.getFileOffset(FileRange.getEnd());
+  return std::make_pair(Offset, EndOffset);
+}
+
+static void makeStandaloneFixIt(const SourceManager &SM,
+                                const LangOptions &LangOpts,
+                                const FixItHint &InFix,
+                                ASTUnit::StandaloneFixIt &OutFix) {
+  OutFix.RemoveRange = makeStandaloneRange(InFix.RemoveRange, SM, LangOpts);
+  OutFix.InsertFromRange = makeStandaloneRange(InFix.InsertFromRange, SM,
+                                               LangOpts);
+  OutFix.CodeToInsert = InFix.CodeToInsert;
+  OutFix.BeforePreviousInsertions = InFix.BeforePreviousInsertions;
+}
+
+static void makeStandaloneDiagnostic(const LangOptions &LangOpts,
+                                     const StoredDiagnostic &InDiag,
+                                     ASTUnit::StandaloneDiagnostic &OutDiag) {
+  OutDiag.ID = InDiag.getID();
+  OutDiag.Level = InDiag.getLevel();
+  OutDiag.Message = InDiag.getMessage();
+  OutDiag.LocOffset = 0;
+  if (InDiag.getLocation().isInvalid())
+    return;
+  const SourceManager &SM = InDiag.getLocation().getManager();
+  SourceLocation FileLoc = SM.getFileLoc(InDiag.getLocation());
+  OutDiag.Filename = SM.getFilename(FileLoc);
+  if (OutDiag.Filename.empty())
+    return;
+  OutDiag.LocOffset = SM.getFileOffset(FileLoc);
+  for (StoredDiagnostic::range_iterator
+         I = InDiag.range_begin(), E = InDiag.range_end(); I != E; ++I) {
+    OutDiag.Ranges.push_back(makeStandaloneRange(*I, SM, LangOpts));
+  }
+  for (StoredDiagnostic::fixit_iterator
+         I = InDiag.fixit_begin(), E = InDiag.fixit_end(); I != E; ++I) {
+    ASTUnit::StandaloneFixIt Fix;
+    makeStandaloneFixIt(SM, LangOpts, *I, Fix);
+    OutDiag.FixIts.push_back(Fix);
+  }
+}
+
 /// \brief Attempt to build or re-use a precompiled preamble when (re-)parsing
 /// the source file.
 ///
@@ -1395,7 +1374,7 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
     = ComputePreamble(*PreambleInvocation, MaxLines, CreatedPreambleBuffer);
 
   // If ComputePreamble() Take ownership of the preamble buffer.
-  OwningPtr<llvm::MemoryBuffer> OwnedPreambleBuffer;
+  std::unique_ptr<llvm::MemoryBuffer> OwnedPreambleBuffer;
   if (CreatedPreambleBuffer)
     OwnedPreambleBuffer.reset(NewPreamble.first);
 
@@ -1407,7 +1386,7 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
 
     // The next time we actually see a preamble, precompile it.
     PreambleRebuildCounter = 1;
-    return 0;
+    return nullptr;
   }
   
   if (!Preamble.empty()) {
@@ -1417,7 +1396,6 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
     // new main file.
     if (Preamble.size() == NewPreamble.second.first &&
         PreambleEndsAtStartOfLine == NewPreamble.second.second &&
-        NewPreamble.first->getBufferSize() < PreambleReservedSize-2 &&
         memcmp(Preamble.getBufferStart(), NewPreamble.first->getBufferStart(),
                NewPreamble.second.first) == 0) {
       // The preamble has not changed. We may be able to re-use the precompiled
@@ -1428,40 +1406,36 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
           
       // First, make a record of those files that have been overridden via
       // remapping or unsaved_files.
-      llvm::StringMap<std::pair<off_t, time_t> > OverriddenFiles;
-      for (PreprocessorOptions::remapped_file_iterator
-                R = PreprocessorOpts.remapped_file_begin(),
-             REnd = PreprocessorOpts.remapped_file_end();
-           !AnyFileChanged && R != REnd;
-           ++R) {
-        llvm::sys::fs::file_status Status;
-        if (FileMgr->getNoncachedStatValue(R->second, Status)) {
+      llvm::StringMap<PreambleFileHash> OverriddenFiles;
+      for (const auto &R : PreprocessorOpts.RemappedFiles) {
+        if (AnyFileChanged)
+          break;
+
+        vfs::Status Status;
+        if (FileMgr->getNoncachedStatValue(R.second, Status)) {
           // If we can't stat the file we're remapping to, assume that something
           // horrible happened.
           AnyFileChanged = true;
           break;
         }
 
-        OverriddenFiles[R->first] = std::make_pair(
+        OverriddenFiles[R.first] = PreambleFileHash::createForFile(
             Status.getSize(), Status.getLastModificationTime().toEpochTime());
       }
-      for (PreprocessorOptions::remapped_file_buffer_iterator
-                R = PreprocessorOpts.remapped_file_buffer_begin(),
-             REnd = PreprocessorOpts.remapped_file_buffer_end();
-           !AnyFileChanged && R != REnd;
-           ++R) {
-        // FIXME: Should we actually compare the contents of file->buffer
-        // remappings?
-        OverriddenFiles[R->first] = std::make_pair(R->second->getBufferSize(), 
-                                                   0);
+
+      for (const auto &RB : PreprocessorOpts.RemappedFileBuffers) {
+        if (AnyFileChanged)
+          break;
+        OverriddenFiles[RB.first] =
+            PreambleFileHash::createForMemoryBuffer(RB.second);
       }
        
       // Check whether anything has changed.
-      for (llvm::StringMap<std::pair<off_t, time_t> >::iterator 
+      for (llvm::StringMap<PreambleFileHash>::iterator 
              F = FilesInPreamble.begin(), FEnd = FilesInPreamble.end();
            !AnyFileChanged && F != FEnd; 
            ++F) {
-        llvm::StringMap<std::pair<off_t, time_t> >::iterator Overridden
+        llvm::StringMap<PreambleFileHash>::iterator Overridden
           = OverriddenFiles.find(F->first());
         if (Overridden != OverriddenFiles.end()) {
           // This file was remapped; check whether the newly-mapped file 
@@ -1472,13 +1446,13 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
         }
         
         // The file was not remapped; check whether it has changed on disk.
-        llvm::sys::fs::file_status Status;
+        vfs::Status Status;
         if (FileMgr->getNoncachedStatValue(F->first(), Status)) {
           // If we can't stat the file, assume that something horrible happened.
           AnyFileChanged = true;
-        } else if (Status.getSize() != uint64_t(F->second.first) ||
+        } else if (Status.getSize() != uint64_t(F->second.Size) ||
                    Status.getLastModificationTime().toEpochTime() !=
-                       uint64_t(F->second.second))
+                       uint64_t(F->second.ModTime))
           AnyFileChanged = true;
       }
           
@@ -1492,18 +1466,15 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
                               PreambleInvocation->getDiagnosticOpts());
         getDiagnostics().setNumWarnings(NumWarningsInPreamble);
 
-        // Create a version of the main file buffer that is padded to
-        // buffer size we reserved when creating the preamble.
-        return CreatePaddedMainFileBuffer(NewPreamble.first, 
-                                          PreambleReservedSize,
-                                          FrontendOpts.Inputs[0].getFile());
+        return llvm::MemoryBuffer::getMemBufferCopy(
+            NewPreamble.first->getBuffer(), FrontendOpts.Inputs[0].getFile());
       }
     }
 
     // If we aren't allowed to rebuild the precompiled preamble, just
     // return now.
     if (!AllowRebuild)
-      return 0;
+      return nullptr;
 
     // We can't reuse the previously-computed preamble. Build a new one.
     Preamble.clear();
@@ -1513,7 +1484,7 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
   } else if (!AllowRebuild) {
     // We aren't allowed to rebuild the precompiled preamble; just
     // return now.
-    return 0;
+    return nullptr;
   }
 
   // If the preamble rebuild counter > 1, it's because we previously
@@ -1521,7 +1492,7 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
   // again. Decrement the counter and return a failure.
   if (PreambleRebuildCounter > 1) {
     --PreambleRebuildCounter;
-    return 0;
+    return nullptr;
   }
 
   // Create a temporary file for the precompiled preamble. In rare 
@@ -1530,26 +1501,16 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
   if (PreamblePCHPath.empty()) {
     // Try again next time.
     PreambleRebuildCounter = 1;
-    return 0;
+    return nullptr;
   }
   
   // We did not previously compute a preamble, or it can't be reused anyway.
   SimpleTimer PreambleTimer(WantTiming);
   PreambleTimer.setOutput("Precompiling preamble");
-  
-  // Create a new buffer that stores the preamble. The buffer also contains
-  // extra space for the original contents of the file (which will be present
-  // when we actually parse the file) along with more room in case the file
-  // grows.  
-  PreambleReservedSize = NewPreamble.first->getBufferSize();
-  if (PreambleReservedSize < 4096)
-    PreambleReservedSize = 8191;
-  else
-    PreambleReservedSize *= 2;
 
   // Save the preamble text for later; we'll need to compare against it for
   // subsequent reparses.
-  StringRef MainFilename = PreambleInvocation->getFrontendOpts().Inputs[0].getFile();
+  StringRef MainFilename = FrontendOpts.Inputs[0].getFile();
   Preamble.assign(FileMgr->getFile(MainFilename),
                   NewPreamble.first->getBufferStart(), 
                   NewPreamble.first->getBufferStart() 
@@ -1558,13 +1519,8 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
 
   delete PreambleBuffer;
   PreambleBuffer
-    = llvm::MemoryBuffer::getNewUninitMemBuffer(PreambleReservedSize,
-                                                FrontendOpts.Inputs[0].getFile());
-  memcpy(const_cast<char*>(PreambleBuffer->getBufferStart()), 
-         NewPreamble.first->getBufferStart(), Preamble.size());
-  memset(const_cast<char*>(PreambleBuffer->getBufferStart()) + Preamble.size(), 
-         ' ', PreambleReservedSize - Preamble.size() - 1);
-  const_cast<char*>(PreambleBuffer->getBufferEnd())[-1] = '\n';  
+    = llvm::MemoryBuffer::getMemBufferCopy(
+        NewPreamble.first->getBuffer().slice(0, Preamble.size()), MainFilename);
 
   // Remap the main source file to the preamble buffer.
   StringRef MainFilePath = FrontendOpts.Inputs[0].getFile();
@@ -1578,7 +1534,7 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
   PreprocessorOpts.PrecompiledPreambleBytes.second = false;
   
   // Create the compiler instance to use for building the precompiled preamble.
-  OwningPtr<CompilerInstance> Clang(new CompilerInstance());
+  std::unique_ptr<CompilerInstance> Clang(new CompilerInstance());
 
   // Recover resources if we crash before exiting this method.
   llvm::CrashRecoveryContextCleanupRegistrar<CompilerInstance>
@@ -1591,22 +1547,21 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
   Clang->setDiagnostics(&getDiagnostics());
   
   // Create the target instance.
-  Clang->setTarget(TargetInfo::CreateTargetInfo(Clang->getDiagnostics(),
-                                                &Clang->getTargetOpts()));
+  Clang->setTarget(TargetInfo::CreateTargetInfo(
+      Clang->getDiagnostics(), Clang->getInvocation().TargetOpts));
   if (!Clang->hasTarget()) {
     llvm::sys::fs::remove(FrontendOpts.OutputFile);
     Preamble.clear();
     PreambleRebuildCounter = DefaultPreambleRebuildInterval;
-    PreprocessorOpts.eraseRemappedFile(
-                               PreprocessorOpts.remapped_file_buffer_end() - 1);
-    return 0;
+    PreprocessorOpts.RemappedFileBuffers.pop_back();
+    return nullptr;
   }
   
   // Inform the target of the language options.
   //
   // FIXME: We shouldn't need to do this, the target should be immutable once
   // created. This complexity should be lifted elsewhere.
-  Clang->getTarget().setForcedLangOptions(Clang->getLangOpts());
+  Clang->getTarget().adjust(Clang->getLangOpts());
   
   assert(Clang->getFrontendOpts().Inputs.size() == 1 &&
          "Invocation must have exactly one source file!");
@@ -1621,28 +1576,49 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
   checkAndRemoveNonDriverDiags(StoredDiagnostics);
   TopLevelDecls.clear();
   TopLevelDeclsInPreamble.clear();
-  
+  PreambleDiagnostics.clear();
+
+  IntrusiveRefCntPtr<vfs::FileSystem> VFS =
+      createVFSFromCompilerInvocation(Clang->getInvocation(), getDiagnostics());
+  if (!VFS)
+    return nullptr;
+
   // Create a file manager object to provide access to and cache the filesystem.
-  Clang->setFileManager(new FileManager(Clang->getFileSystemOpts()));
+  Clang->setFileManager(new FileManager(Clang->getFileSystemOpts(), VFS));
   
   // Create the source manager.
   Clang->setSourceManager(new SourceManager(getDiagnostics(),
                                             Clang->getFileManager()));
-  
-  OwningPtr<PrecompilePreambleAction> Act;
+
+  auto PreambleDepCollector = std::make_shared<DependencyCollector>();
+  Clang->addDependencyCollector(PreambleDepCollector);
+
+  std::unique_ptr<PrecompilePreambleAction> Act;
   Act.reset(new PrecompilePreambleAction(*this));
   if (!Act->BeginSourceFile(*Clang.get(), Clang->getFrontendOpts().Inputs[0])) {
     llvm::sys::fs::remove(FrontendOpts.OutputFile);
     Preamble.clear();
     PreambleRebuildCounter = DefaultPreambleRebuildInterval;
-    PreprocessorOpts.eraseRemappedFile(
-                               PreprocessorOpts.remapped_file_buffer_end() - 1);
-    return 0;
+    PreprocessorOpts.RemappedFileBuffers.pop_back();
+    return nullptr;
   }
   
   Act->Execute();
+
+  // Transfer any diagnostics generated when parsing the preamble into the set
+  // of preamble diagnostics.
+  for (stored_diag_iterator
+         I = stored_diag_afterDriver_begin(),
+         E = stored_diag_end(); I != E; ++I) {
+    StandaloneDiagnostic Diag;
+    makeStandaloneDiagnostic(Clang->getLangOpts(), *I, Diag);
+    PreambleDiagnostics.push_back(Diag);
+  }
+
   Act->EndSourceFile();
 
+  checkAndRemoveNonDriverDiags(StoredDiagnostics);
+
   if (!Act->hasEmittedPreamblePCH()) {
     // The preamble PCH failed (e.g. there was a module loading fatal error),
     // so no precompiled header was generated. Forget that we even tried.
@@ -1651,18 +1627,10 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
     Preamble.clear();
     TopLevelDeclsInPreamble.clear();
     PreambleRebuildCounter = DefaultPreambleRebuildInterval;
-    PreprocessorOpts.eraseRemappedFile(
-                               PreprocessorOpts.remapped_file_buffer_end() - 1);
-    return 0;
+    PreprocessorOpts.RemappedFileBuffers.pop_back();
+    return nullptr;
   }
   
-  // Transfer any diagnostics generated when parsing the preamble into the set
-  // of preamble diagnostics.
-  PreambleDiagnostics.clear();
-  PreambleDiagnostics.insert(PreambleDiagnostics.end(), 
-                            stored_diag_afterDriver_begin(), stored_diag_end());
-  checkAndRemoveNonDriverDiags(StoredDiagnostics);
-  
   // Keep track of the preamble we precompiled.
   setPreambleFile(this, FrontendOpts.OutputFile);
   NumWarningsInPreamble = getDiagnostics().getNumWarnings();
@@ -1671,24 +1639,23 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
   // so we can verify whether they have changed or not.
   FilesInPreamble.clear();
   SourceManager &SourceMgr = Clang->getSourceManager();
-  const llvm::MemoryBuffer *MainFileBuffer
-    = SourceMgr.getBuffer(SourceMgr.getMainFileID());
-  for (SourceManager::fileinfo_iterator F = SourceMgr.fileinfo_begin(),
-                                     FEnd = SourceMgr.fileinfo_end();
-       F != FEnd;
-       ++F) {
-    const FileEntry *File = F->second->OrigEntry;
-    if (!File || F->second->getRawBuffer() == MainFileBuffer)
+  for (auto &Filename : PreambleDepCollector->getDependencies()) {
+    const FileEntry *File = Clang->getFileManager().getFile(Filename);
+    if (!File || File == SourceMgr.getFileEntryForID(SourceMgr.getMainFileID()))
       continue;
-    
-    FilesInPreamble[File->getName()]
-      = std::make_pair(F->second->getSize(), File->getModificationTime());
+    if (time_t ModTime = File->getModificationTime()) {
+      FilesInPreamble[File->getName()] = PreambleFileHash::createForFile(
+          File->getSize(), ModTime);
+    } else {
+      llvm::MemoryBuffer *Buffer = SourceMgr.getMemoryBufferForFile(File);
+      FilesInPreamble[File->getName()] =
+          PreambleFileHash::createForMemoryBuffer(Buffer);
+    }
   }
-  
+
   PreambleRebuildCounter = 1;
-  PreprocessorOpts.eraseRemappedFile(
-                               PreprocessorOpts.remapped_file_buffer_end() - 1);
-  
+  PreprocessorOpts.RemappedFileBuffers.pop_back();
+
   // If the hash of top-level entities differs from the hash of the top-level
   // entities the last time we rebuilt the preamble, clear out the completion
   // cache.
@@ -1697,9 +1664,8 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
     PreambleTopLevelHashValue = CurrentTopLevelHashValue;
   }
   
-  return CreatePaddedMainFileBuffer(NewPreamble.first, 
-                                    PreambleReservedSize,
-                                    FrontendOpts.Inputs[0].getFile());
+  return llvm::MemoryBuffer::getMemBufferCopy(NewPreamble.first->getBuffer(),
+                                              MainFilename);
 }
 
 void ASTUnit::RealizeTopLevelDeclsFromPreamble() {
@@ -1718,14 +1684,20 @@ void ASTUnit::RealizeTopLevelDeclsFromPreamble() {
 }
 
 void ASTUnit::transferASTDataFromCompilerInstance(CompilerInstance &CI) {
-  // Steal the created target, context, and preprocessor.
+  // Steal the created target, context, and preprocessor if they have been
+  // created.
+  assert(CI.hasInvocation() && "missing invocation");
+  LangOpts = CI.getInvocation().LangOpts;
   TheSema.reset(CI.takeSema());
   Consumer.reset(CI.takeASTConsumer());
-  Ctx = &CI.getASTContext();
-  PP = &CI.getPreprocessor();
-  CI.setSourceManager(0);
-  CI.setFileManager(0);
-  Target = &CI.getTarget();
+  if (CI.hasASTContext())
+    Ctx = &CI.getASTContext();
+  if (CI.hasPreprocessor())
+    PP = &CI.getPreprocessor();
+  CI.setSourceManager(nullptr);
+  CI.setFileManager(nullptr);
+  if (CI.hasTarget())
+    Target = &CI.getTarget();
   Reader = CI.getModuleManager();
   HadModuleLoaderFatalFailure = CI.hadModuleLoaderFatalFailure();
 }
@@ -1761,41 +1733,41 @@ ASTUnit *ASTUnit::create(CompilerInvocation *CI,
                          IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
                          bool CaptureDiagnostics,
                          bool UserFilesAreVolatile) {
-  OwningPtr<ASTUnit> AST;
+  std::unique_ptr<ASTUnit> AST;
   AST.reset(new ASTUnit(false));
-  ConfigureDiags(Diags, 0, 0, *AST, CaptureDiagnostics);
+  ConfigureDiags(Diags, nullptr, nullptr, *AST, CaptureDiagnostics);
   AST->Diagnostics = Diags;
   AST->Invocation = CI;
   AST->FileSystemOpts = CI->getFileSystemOpts();
-  AST->FileMgr = new FileManager(AST->FileSystemOpts);
+  IntrusiveRefCntPtr<vfs::FileSystem> VFS =
+      createVFSFromCompilerInvocation(*CI, *Diags);
+  if (!VFS)
+    return nullptr;
+  AST->FileMgr = new FileManager(AST->FileSystemOpts, VFS);
   AST->UserFilesAreVolatile = UserFilesAreVolatile;
   AST->SourceMgr = new SourceManager(AST->getDiagnostics(), *AST->FileMgr,
                                      UserFilesAreVolatile);
 
-  return AST.take();
+  return AST.release();
 }
 
-ASTUnit *ASTUnit::LoadFromCompilerInvocationAction(CompilerInvocation *CI,
-                              IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
-                                             ASTFrontendAction *Action,
-                                             ASTUnit *Unit,
-                                             bool Persistent,
-                                             StringRef ResourceFilesPath,
-                                             bool OnlyLocalDecls,
-                                             bool CaptureDiagnostics,
-                                             bool PrecompilePreamble,
-                                             bool CacheCodeCompletionResults,
-                                    bool IncludeBriefCommentsInCodeCompletion,
-                                             bool UserFilesAreVolatile,
-                                             OwningPtr<ASTUnit> *ErrAST) {
+ASTUnit *ASTUnit::LoadFromCompilerInvocationAction(
+    CompilerInvocation *CI, IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
+    ASTFrontendAction *Action, ASTUnit *Unit, bool Persistent,
+    StringRef ResourceFilesPath, bool OnlyLocalDecls, bool CaptureDiagnostics,
+    bool PrecompilePreamble, bool CacheCodeCompletionResults,
+    bool IncludeBriefCommentsInCodeCompletion, bool UserFilesAreVolatile,
+    std::unique_ptr<ASTUnit> *ErrAST) {
   assert(CI && "A CompilerInvocation is required");
 
-  OwningPtr<ASTUnit> OwnAST;
+  std::unique_ptr<ASTUnit> OwnAST;
   ASTUnit *AST = Unit;
   if (!AST) {
     // Create the AST unit.
     OwnAST.reset(create(CI, Diags, CaptureDiagnostics, UserFilesAreVolatile));
     AST = OwnAST.get();
+    if (!AST)
+      return nullptr;
   }
   
   if (!ResourceFilesPath.empty()) {
@@ -1816,7 +1788,7 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocationAction(CompilerInvocation *CI,
     ASTUnitCleanup(OwnAST.get());
   llvm::CrashRecoveryContextCleanupRegistrar<DiagnosticsEngine,
     llvm::CrashRecoveryContextReleaseRefCleanup<DiagnosticsEngine> >
-    DiagCleanup(Diags.getPtr());
+    DiagCleanup(Diags.get());
 
   // We'll manage file buffers ourselves.
   CI->getPreprocessorOpts().RetainRemappedFileBuffers = true;
@@ -1824,7 +1796,7 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocationAction(CompilerInvocation *CI,
   ProcessWarningOptions(AST->getDiagnostics(), CI->getDiagnosticOpts());
 
   // Create the compiler instance to use for building the AST.
-  OwningPtr<CompilerInstance> Clang(new CompilerInstance());
+  std::unique_ptr<CompilerInstance> Clang(new CompilerInstance());
 
   // Recover resources if we crash before exiting this method.
   llvm::CrashRecoveryContextCleanupRegistrar<CompilerInstance>
@@ -1838,16 +1810,16 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocationAction(CompilerInvocation *CI,
   Clang->setDiagnostics(&AST->getDiagnostics());
   
   // Create the target instance.
-  Clang->setTarget(TargetInfo::CreateTargetInfo(Clang->getDiagnostics(),
-                                                &Clang->getTargetOpts()));
+  Clang->setTarget(TargetInfo::CreateTargetInfo(
+      Clang->getDiagnostics(), Clang->getInvocation().TargetOpts));
   if (!Clang->hasTarget())
-    return 0;
+    return nullptr;
 
   // Inform the target of the language options.
   //
   // FIXME: We shouldn't need to do this, the target should be immutable once
   // created. This complexity should be lifted elsewhere.
-  Clang->getTarget().setForcedLangOptions(Clang->getLangOpts());
+  Clang->getTarget().adjust(Clang->getLangOpts());
   
   assert(Clang->getFrontendOpts().Inputs.size() == 1 &&
          "Invocation must have exactly one source file!");
@@ -1858,10 +1830,10 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocationAction(CompilerInvocation *CI,
 
   // Configure the various subsystems.
   AST->TheSema.reset();
-  AST->Ctx = 0;
-  AST->PP = 0;
-  AST->Reader = 0;
-  
+  AST->Ctx = nullptr;
+  AST->PP = nullptr;
+  AST->Reader = nullptr;
+
   // Create a file manager object to provide access to and cache the filesystem.
   Clang->setFileManager(&AST->getFileManager());
   
@@ -1870,7 +1842,7 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocationAction(CompilerInvocation *CI,
 
   ASTFrontendAction *Act = Action;
 
-  OwningPtr<TopLevelDeclTrackerAction> TrackerAct;
+  std::unique_ptr<TopLevelDeclTrackerAction> TrackerAct;
   if (!Act) {
     TrackerAct.reset(new TopLevelDeclTrackerAction(*AST));
     Act = TrackerAct.get();
@@ -1885,7 +1857,7 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocationAction(CompilerInvocation *CI,
     if (OwnAST && ErrAST)
       ErrAST->swap(OwnAST);
 
-    return 0;
+    return nullptr;
   }
 
   if (Persistent && !TrackerAct) {
@@ -1903,7 +1875,7 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocationAction(CompilerInvocation *CI,
     if (OwnAST && ErrAST)
       ErrAST->swap(OwnAST);
 
-    return 0;
+    return nullptr;
   }
 
   // Steal the created target, context, and preprocessor.
@@ -1912,7 +1884,7 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocationAction(CompilerInvocation *CI,
   Act->EndSourceFile();
 
   if (OwnAST)
-    return OwnAST.take();
+    return OwnAST.release();
   else
     return AST;
 }
@@ -1926,7 +1898,7 @@ bool ASTUnit::LoadFromCompilerInvocation(bool PrecompilePreamble) {
   Invocation->getFrontendOpts().DisableFree = false;
   ProcessWarningOptions(getDiagnostics(), Invocation->getDiagnosticOpts());
 
-  llvm::MemoryBuffer *OverrideMainBuffer = 0;
+  llvm::MemoryBuffer *OverrideMainBuffer = nullptr;
   if (PrecompilePreamble) {
     PreambleRebuildCounter = 2;
     OverrideMainBuffer
@@ -1943,19 +1915,14 @@ bool ASTUnit::LoadFromCompilerInvocation(bool PrecompilePreamble) {
   return Parse(OverrideMainBuffer);
 }
 
-ASTUnit *ASTUnit::LoadFromCompilerInvocation(CompilerInvocation *CI,
-                              IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
-                                             bool OnlyLocalDecls,
-                                             bool CaptureDiagnostics,
-                                             bool PrecompilePreamble,
-                                             TranslationUnitKind TUKind,
-                                             bool CacheCodeCompletionResults,
-                                    bool IncludeBriefCommentsInCodeCompletion,
-                                             bool UserFilesAreVolatile) {
+std::unique_ptr<ASTUnit> ASTUnit::LoadFromCompilerInvocation(
+    CompilerInvocation *CI, IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
+    bool OnlyLocalDecls, bool CaptureDiagnostics, bool PrecompilePreamble,
+    TranslationUnitKind TUKind, bool CacheCodeCompletionResults,
+    bool IncludeBriefCommentsInCodeCompletion, bool UserFilesAreVolatile) {
   // Create the AST unit.
-  OwningPtr<ASTUnit> AST;
-  AST.reset(new ASTUnit(false));
-  ConfigureDiags(Diags, 0, 0, *AST, CaptureDiagnostics);
+  std::unique_ptr<ASTUnit> AST(new ASTUnit(false));
+  ConfigureDiags(Diags, nullptr, nullptr, *AST, CaptureDiagnostics);
   AST->Diagnostics = Diags;
   AST->OnlyLocalDecls = OnlyLocalDecls;
   AST->CaptureDiagnostics = CaptureDiagnostics;
@@ -1965,7 +1932,11 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocation(CompilerInvocation *CI,
     = IncludeBriefCommentsInCodeCompletion;
   AST->Invocation = CI;
   AST->FileSystemOpts = CI->getFileSystemOpts();
-  AST->FileMgr = new FileManager(AST->FileSystemOpts);
+  IntrusiveRefCntPtr<vfs::FileSystem> VFS =
+      createVFSFromCompilerInvocation(*CI, *Diags);
+  if (!VFS)
+    return nullptr;
+  AST->FileMgr = new FileManager(AST->FileSystemOpts, VFS);
   AST->UserFilesAreVolatile = UserFilesAreVolatile;
   
   // Recover resources if we crash before exiting this method.
@@ -1973,30 +1944,24 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocation(CompilerInvocation *CI,
     ASTUnitCleanup(AST.get());
   llvm::CrashRecoveryContextCleanupRegistrar<DiagnosticsEngine,
     llvm::CrashRecoveryContextReleaseRefCleanup<DiagnosticsEngine> >
-    DiagCleanup(Diags.getPtr());
-
-  return AST->LoadFromCompilerInvocation(PrecompilePreamble)? 0 : AST.take();
-}
-
-ASTUnit *ASTUnit::LoadFromCommandLine(const char **ArgBegin,
-                                      const char **ArgEnd,
-                                    IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
-                                      StringRef ResourceFilesPath,
-                                      bool OnlyLocalDecls,
-                                      bool CaptureDiagnostics,
-                                      RemappedFile *RemappedFiles,
-                                      unsigned NumRemappedFiles,
-                                      bool RemappedFilesKeepOriginalName,
-                                      bool PrecompilePreamble,
-                                      TranslationUnitKind TUKind,
-                                      bool CacheCodeCompletionResults,
-                                      bool IncludeBriefCommentsInCodeCompletion,
-                                      bool AllowPCHWithCompilerErrors,
-                                      bool SkipFunctionBodies,
-                                      bool UserFilesAreVolatile,
-                                      bool ForSerialization,
-                                      OwningPtr<ASTUnit> *ErrAST) {
-  if (!Diags.getPtr()) {
+    DiagCleanup(Diags.get());
+
+  if (AST->LoadFromCompilerInvocation(PrecompilePreamble))
+    return nullptr;
+  return AST;
+}
+
+ASTUnit *ASTUnit::LoadFromCommandLine(
+    const char **ArgBegin, const char **ArgEnd,
+    IntrusiveRefCntPtr<DiagnosticsEngine> Diags, StringRef ResourceFilesPath,
+    bool OnlyLocalDecls, bool CaptureDiagnostics,
+    ArrayRef<RemappedFile> RemappedFiles, bool RemappedFilesKeepOriginalName,
+    bool PrecompilePreamble, TranslationUnitKind TUKind,
+    bool CacheCodeCompletionResults, bool IncludeBriefCommentsInCodeCompletion,
+    bool AllowPCHWithCompilerErrors, bool SkipFunctionBodies,
+    bool UserFilesAreVolatile, bool ForSerialization,
+    std::unique_ptr<ASTUnit> *ErrAST) {
+  if (!Diags.get()) {
     // No diagnostics engine was provided, so create our own diagnostics object
     // with the default options.
     Diags = CompilerInstance::createDiagnostics(new DiagnosticOptions());
@@ -2015,19 +1980,13 @@ ASTUnit *ASTUnit::LoadFromCommandLine(const char **ArgBegin,
                                            llvm::makeArrayRef(ArgBegin, ArgEnd),
                                            Diags);
     if (!CI)
-      return 0;
+      return nullptr;
   }
 
   // Override any files that need remapping
-  for (unsigned I = 0; I != NumRemappedFiles; ++I) {
-    FilenameOrMemBuf fileOrBuf = RemappedFiles[I].second;
-    if (const llvm::MemoryBuffer *
-            memBuf = fileOrBuf.dyn_cast<const llvm::MemoryBuffer *>()) {
-      CI->getPreprocessorOpts().addRemappedFile(RemappedFiles[I].first, memBuf);
-    } else {
-      const char *fname = fileOrBuf.get<const char *>();
-      CI->getPreprocessorOpts().addRemappedFile(RemappedFiles[I].first, fname);
-    }
+  for (unsigned I = 0, N = RemappedFiles.size(); I != N; ++I) {
+    CI->getPreprocessorOpts().addRemappedFile(RemappedFiles[I].first,
+                                              RemappedFiles[I].second);
   }
   PreprocessorOptions &PPOpts = CI->getPreprocessorOpts();
   PPOpts.RemappedFilesKeepOriginalName = RemappedFilesKeepOriginalName;
@@ -2039,13 +1998,17 @@ ASTUnit *ASTUnit::LoadFromCommandLine(const char **ArgBegin,
   CI->getFrontendOpts().SkipFunctionBodies = SkipFunctionBodies;
 
   // Create the AST unit.
-  OwningPtr<ASTUnit> AST;
+  std::unique_ptr<ASTUnit> AST;
   AST.reset(new ASTUnit(false));
   ConfigureDiags(Diags, ArgBegin, ArgEnd, *AST, CaptureDiagnostics);
   AST->Diagnostics = Diags;
-  Diags = 0; // Zero out now to ease cleanup during crash recovery.
+  Diags = nullptr; // Zero out now to ease cleanup during crash recovery.
   AST->FileSystemOpts = CI->getFileSystemOpts();
-  AST->FileMgr = new FileManager(AST->FileSystemOpts);
+  IntrusiveRefCntPtr<vfs::FileSystem> VFS =
+      createVFSFromCompilerInvocation(*CI, *Diags);
+  if (!VFS)
+    return nullptr;
+  AST->FileMgr = new FileManager(AST->FileSystemOpts, VFS);
   AST->OnlyLocalDecls = OnlyLocalDecls;
   AST->CaptureDiagnostics = CaptureDiagnostics;
   AST->TUKind = TUKind;
@@ -2058,8 +2021,8 @@ ASTUnit *ASTUnit::LoadFromCommandLine(const char **ArgBegin,
   AST->Invocation = CI;
   if (ForSerialization)
     AST->WriterData.reset(new ASTWriterData());
-  CI = 0; // Zero out now to ease cleanup during crash recovery.
-  
+  CI = nullptr; // Zero out now to ease cleanup during crash recovery.
+
   // Recover resources if we crash before exiting this method.
   llvm::CrashRecoveryContextCleanupRegistrar<ASTUnit>
     ASTUnitCleanup(AST.get());
@@ -2071,13 +2034,13 @@ ASTUnit *ASTUnit::LoadFromCommandLine(const char **ArgBegin,
       AST->StoredDiagnostics.swap(AST->FailedParseDiagnostics);
       ErrAST->swap(AST);
     }
-    return 0;
+    return nullptr;
   }
 
-  return AST.take();
+  return AST.release();
 }
 
-bool ASTUnit::Reparse(RemappedFile *RemappedFiles, unsigned NumRemappedFiles) {
+bool ASTUnit::Reparse(ArrayRef<RemappedFile> RemappedFiles) {
   if (!Invocation)
     return true;
 
@@ -2088,30 +2051,18 @@ bool ASTUnit::Reparse(RemappedFile *RemappedFiles, unsigned NumRemappedFiles) {
 
   // Remap files.
   PreprocessorOptions &PPOpts = Invocation->getPreprocessorOpts();
-  for (PreprocessorOptions::remapped_file_buffer_iterator 
-         R = PPOpts.remapped_file_buffer_begin(),
-         REnd = PPOpts.remapped_file_buffer_end();
-       R != REnd; 
-       ++R) {
-    delete R->second;
-  }
+  for (const auto &RB : PPOpts.RemappedFileBuffers)
+    delete RB.second;
+
   Invocation->getPreprocessorOpts().clearRemappedFiles();
-  for (unsigned I = 0; I != NumRemappedFiles; ++I) {
-    FilenameOrMemBuf fileOrBuf = RemappedFiles[I].second;
-    if (const llvm::MemoryBuffer *
-            memBuf = fileOrBuf.dyn_cast<const llvm::MemoryBuffer *>()) {
-      Invocation->getPreprocessorOpts().addRemappedFile(RemappedFiles[I].first,
-                                                        memBuf);
-    } else {
-      const char *fname = fileOrBuf.get<const char *>();
-      Invocation->getPreprocessorOpts().addRemappedFile(RemappedFiles[I].first,
-                                                        fname);
-    }
+  for (unsigned I = 0, N = RemappedFiles.size(); I != N; ++I) {
+    Invocation->getPreprocessorOpts().addRemappedFile(RemappedFiles[I].first,
+                                                      RemappedFiles[I].second);
   }
-  
+
   // If we have a preamble file lying around, or if we might try to
   // build a precompiled preamble, do so now.
-  llvm::MemoryBuffer *OverrideMainBuffer = 0;
+  llvm::MemoryBuffer *OverrideMainBuffer = nullptr;
   if (!getPreambleFile(this).empty() || PreambleRebuildCounter > 0)
     OverrideMainBuffer = getMainBufferWithPrecompiledPreamble(*Invocation);
     
@@ -2178,23 +2129,22 @@ namespace {
                        |  (1LL << CodeCompletionContext::CCC_UnionTag)
                        |  (1LL << CodeCompletionContext::CCC_ClassOrStructTag);
     }
-    
-    virtual void ProcessCodeCompleteResults(Sema &S, 
-                                            CodeCompletionContext Context,
-                                            CodeCompletionResult *Results,
-                                            unsigned NumResults);
-    
-    virtual void ProcessOverloadCandidates(Sema &S, unsigned CurrentArg,
-                                           OverloadCandidate *Candidates,
-                                           unsigned NumCandidates) { 
+
+    void ProcessCodeCompleteResults(Sema &S, CodeCompletionContext Context,
+                                    CodeCompletionResult *Results,
+                                    unsigned NumResults) override;
+
+    void ProcessOverloadCandidates(Sema &S, unsigned CurrentArg,
+                                   OverloadCandidate *Candidates,
+                                   unsigned NumCandidates) override {
       Next.ProcessOverloadCandidates(S, CurrentArg, Candidates, NumCandidates);
     }
-    
-    virtual CodeCompletionAllocator &getAllocator() {
+
+    CodeCompletionAllocator &getAllocator() override {
       return Next.getAllocator();
     }
 
-    virtual CodeCompletionTUInfo &getCodeCompletionTUInfo() {
+    CodeCompletionTUInfo &getCodeCompletionTUInfo() override {
       return Next.getCodeCompletionTUInfo();
     }
   };
@@ -2378,8 +2328,7 @@ void AugmentedCodeCompleteConsumer::ProcessCodeCompleteResults(Sema &S,
 
 
 void ASTUnit::CodeComplete(StringRef File, unsigned Line, unsigned Column,
-                           RemappedFile *RemappedFiles, 
-                           unsigned NumRemappedFiles,
+                           ArrayRef<RemappedFile> RemappedFiles,
                            bool IncludeMacros, 
                            bool IncludeCodePatterns,
                            bool IncludeBriefComments,
@@ -2417,7 +2366,7 @@ void ASTUnit::CodeComplete(StringRef File, unsigned Line, unsigned Column,
   // Set the language options appropriately.
   LangOpts = *CCInvocation->getLangOpts();
 
-  OwningPtr<CompilerInstance> Clang(new CompilerInstance());
+  std::unique_ptr<CompilerInstance> Clang(new CompilerInstance());
 
   // Recover resources if we crash before exiting this method.
   llvm::CrashRecoveryContextCleanupRegistrar<CompilerInstance>
@@ -2434,10 +2383,10 @@ void ASTUnit::CodeComplete(StringRef File, unsigned Line, unsigned Column,
   ProcessWarningOptions(Diag, CCInvocation->getDiagnosticOpts());
   
   // Create the target instance.
-  Clang->setTarget(TargetInfo::CreateTargetInfo(Clang->getDiagnostics(),
-                                                &Clang->getTargetOpts()));
+  Clang->setTarget(TargetInfo::CreateTargetInfo(
+      Clang->getDiagnostics(), Clang->getInvocation().TargetOpts));
   if (!Clang->hasTarget()) {
-    Clang->setInvocation(0);
+    Clang->setInvocation(nullptr);
     return;
   }
   
@@ -2445,7 +2394,7 @@ void ASTUnit::CodeComplete(StringRef File, unsigned Line, unsigned Column,
   //
   // FIXME: We shouldn't need to do this, the target should be immutable once
   // created. This complexity should be lifted elsewhere.
-  Clang->getTarget().setForcedLangOptions(Clang->getLangOpts());
+  Clang->getTarget().adjust(Clang->getLangOpts());
   
   assert(Clang->getFrontendOpts().Inputs.size() == 1 &&
          "Invocation must have exactly one source file!");
@@ -2462,18 +2411,12 @@ void ASTUnit::CodeComplete(StringRef File, unsigned Line, unsigned Column,
   // Remap files.
   PreprocessorOpts.clearRemappedFiles();
   PreprocessorOpts.RetainRemappedFileBuffers = true;
-  for (unsigned I = 0; I != NumRemappedFiles; ++I) {
-    FilenameOrMemBuf fileOrBuf = RemappedFiles[I].second;
-    if (const llvm::MemoryBuffer *
-            memBuf = fileOrBuf.dyn_cast<const llvm::MemoryBuffer *>()) {
-      PreprocessorOpts.addRemappedFile(RemappedFiles[I].first, memBuf);
-      OwnedBuffers.push_back(memBuf);
-    } else {
-      const char *fname = fileOrBuf.get<const char *>();
-      PreprocessorOpts.addRemappedFile(RemappedFiles[I].first, fname);
-    }
+  for (unsigned I = 0, N = RemappedFiles.size(); I != N; ++I) {
+    PreprocessorOpts.addRemappedFile(RemappedFiles[I].first,
+                                     RemappedFiles[I].second);
+    OwnedBuffers.push_back(RemappedFiles[I].second);
   }
-  
+
   // Use the code completion consumer we were given, but adding any cached
   // code-completion results.
   AugmentedCodeCompleteConsumer *AugmentedConsumer
@@ -2484,7 +2427,7 @@ void ASTUnit::CodeComplete(StringRef File, unsigned Line, unsigned Column,
   // the use of the precompiled preamble if we're if the completion
   // point is within the main file, after the end of the precompiled
   // preamble.
-  llvm::MemoryBuffer *OverrideMainBuffer = 0;
+  llvm::MemoryBuffer *OverrideMainBuffer = nullptr;
   if (!getPreambleFile(this).empty()) {
     std::string CompleteFilePath(File);
     llvm::sys::fs::UniqueID CompleteFileID;
@@ -2520,8 +2463,8 @@ void ASTUnit::CodeComplete(StringRef File, unsigned Line, unsigned Column,
   // Disable the preprocessing record if modules are not enabled.
   if (!Clang->getLangOpts().Modules)
     PreprocessorOpts.DetailedRecord = false;
-  
-  OwningPtr<SyntaxOnlyAction> Act;
+
+  std::unique_ptr<SyntaxOnlyAction> Act;
   Act.reset(new SyntaxOnlyAction);
   if (Act->BeginSourceFile(*Clang.get(), Clang->getFrontendOpts().Inputs[0])) {
     Act->Execute();
@@ -2554,8 +2497,7 @@ bool ASTUnit::Save(StringRef File) {
   }
 
   if (llvm::sys::fs::rename(TempPath.str(), File)) {
-    bool exists;
-    llvm::sys::fs::remove(TempPath.str(), exists);
+    llvm::sys::fs::remove(TempPath.str());
     return true;
   }
 
@@ -2567,7 +2509,7 @@ static bool serializeUnit(ASTWriter &Writer,
                           Sema &S,
                           bool hasErrors,
                           raw_ostream &OS) {
-  Writer.WriteAST(S, std::string(), 0, "", hasErrors);
+  Writer.WriteAST(S, std::string(), nullptr, "", hasErrors);
 
   // Write the generated bitstream to "Out".
   if (!Buffer.empty())
@@ -2591,68 +2533,57 @@ bool ASTUnit::serialize(raw_ostream &OS) {
 
 typedef ContinuousRangeMap<unsigned, int, 2> SLocRemap;
 
-static void TranslateSLoc(SourceLocation &L, SLocRemap &Remap) {
-  unsigned Raw = L.getRawEncoding();
-  const unsigned MacroBit = 1U << 31;
-  L = SourceLocation::getFromRawEncoding((Raw & MacroBit) |
-      ((Raw & ~MacroBit) + Remap.find(Raw & ~MacroBit)->second));
-}
-
 void ASTUnit::TranslateStoredDiagnostics(
-                          ASTReader *MMan,
-                          StringRef ModName,
+                          FileManager &FileMgr,
                           SourceManager &SrcMgr,
-                          const SmallVectorImpl<StoredDiagnostic> &Diags,
+                          const SmallVectorImpl<StandaloneDiagnostic> &Diags,
                           SmallVectorImpl<StoredDiagnostic> &Out) {
-  // The stored diagnostic has the old source manager in it; update
-  // the locations to refer into the new source manager. We also need to remap
-  // all the locations to the new view. This includes the diag location, any
-  // associated source ranges, and the source ranges of associated fix-its.
+  // Map the standalone diagnostic into the new source manager. We also need to
+  // remap all the locations to the new view. This includes the diag location,
+  // any associated source ranges, and the source ranges of associated fix-its.
   // FIXME: There should be a cleaner way to do this.
 
   SmallVector<StoredDiagnostic, 4> Result;
   Result.reserve(Diags.size());
-  assert(MMan && "Don't have a module manager");
-  serialization::ModuleFile *Mod = MMan->ModuleMgr.lookup(ModName);
-  assert(Mod && "Don't have preamble module");
-  SLocRemap &Remap = Mod->SLocRemap;
   for (unsigned I = 0, N = Diags.size(); I != N; ++I) {
     // Rebuild the StoredDiagnostic.
-    const StoredDiagnostic &SD = Diags[I];
-    SourceLocation L = SD.getLocation();
-    TranslateSLoc(L, Remap);
+    const StandaloneDiagnostic &SD = Diags[I];
+    if (SD.Filename.empty())
+      continue;
+    const FileEntry *FE = FileMgr.getFile(SD.Filename);
+    if (!FE)
+      continue;
+    FileID FID = SrcMgr.translateFile(FE);
+    SourceLocation FileLoc = SrcMgr.getLocForStartOfFile(FID);
+    if (FileLoc.isInvalid())
+      continue;
+    SourceLocation L = FileLoc.getLocWithOffset(SD.LocOffset);
     FullSourceLoc Loc(L, SrcMgr);
 
     SmallVector<CharSourceRange, 4> Ranges;
-    Ranges.reserve(SD.range_size());
-    for (StoredDiagnostic::range_iterator I = SD.range_begin(),
-                                          E = SD.range_end();
-         I != E; ++I) {
-      SourceLocation BL = I->getBegin();
-      TranslateSLoc(BL, Remap);
-      SourceLocation EL = I->getEnd();
-      TranslateSLoc(EL, Remap);
-      Ranges.push_back(CharSourceRange(SourceRange(BL, EL), I->isTokenRange()));
+    Ranges.reserve(SD.Ranges.size());
+    for (std::vector<std::pair<unsigned, unsigned> >::const_iterator
+           I = SD.Ranges.begin(), E = SD.Ranges.end(); I != E; ++I) {
+      SourceLocation BL = FileLoc.getLocWithOffset((*I).first);
+      SourceLocation EL = FileLoc.getLocWithOffset((*I).second);
+      Ranges.push_back(CharSourceRange::getCharRange(BL, EL));
     }
 
     SmallVector<FixItHint, 2> FixIts;
-    FixIts.reserve(SD.fixit_size());
-    for (StoredDiagnostic::fixit_iterator I = SD.fixit_begin(),
-                                          E = SD.fixit_end();
+    FixIts.reserve(SD.FixIts.size());
+    for (std::vector<StandaloneFixIt>::const_iterator
+           I = SD.FixIts.begin(), E = SD.FixIts.end();
          I != E; ++I) {
       FixIts.push_back(FixItHint());
       FixItHint &FH = FixIts.back();
       FH.CodeToInsert = I->CodeToInsert;
-      SourceLocation BL = I->RemoveRange.getBegin();
-      TranslateSLoc(BL, Remap);
-      SourceLocation EL = I->RemoveRange.getEnd();
-      TranslateSLoc(EL, Remap);
-      FH.RemoveRange = CharSourceRange(SourceRange(BL, EL),
-                                       I->RemoveRange.isTokenRange());
+      SourceLocation BL = FileLoc.getLocWithOffset(I->RemoveRange.first);
+      SourceLocation EL = FileLoc.getLocWithOffset(I->RemoveRange.second);
+      FH.RemoveRange = CharSourceRange::getCharRange(BL, EL);
     }
 
-    Result.push_back(StoredDiagnostic(SD.getLevel(), SD.getID(), 
-                                      SD.getMessage(), Loc, Ranges, FixIts));
+    Result.push_back(StoredDiagnostic(SD.Level, SD.ID, 
+                                      SD.Message, Loc, Ranges, FixIts));
   }
   Result.swap(Out);
 }
@@ -2677,7 +2608,7 @@ void ASTUnit::addFileLevelDecl(Decl *D) {
   assert(SM.isLocalSourceLocation(FileLoc));
   FileID FID;
   unsigned Offset;
-  llvm::tie(FID, Offset) = SM.getDecomposedLoc(FileLoc);
+  std::tie(FID, Offset) = SM.getDecomposedLoc(FileLoc);
   if (FID.isInvalid())
     return;
 
@@ -2719,7 +2650,8 @@ void ASTUnit::findFileRegionDecls(FileID File, unsigned Offset, unsigned Length,
 
   LocDeclsTy::iterator BeginIt =
       std::lower_bound(LocDecls.begin(), LocDecls.end(),
-                       std::make_pair(Offset, (Decl *)0), llvm::less_first());
+                       std::make_pair(Offset, (Decl *)nullptr),
+                       llvm::less_first());
   if (BeginIt != LocDecls.begin())
     --BeginIt;
 
@@ -2732,7 +2664,7 @@ void ASTUnit::findFileRegionDecls(FileID File, unsigned Offset, unsigned Length,
 
   LocDeclsTy::iterator EndIt = std::upper_bound(
       LocDecls.begin(), LocDecls.end(),
-      std::make_pair(Offset + Length, (Decl *)0), llvm::less_first());
+      std::make_pair(Offset + Length, (Decl *)nullptr), llvm::less_first());
   if (EndIt != LocDecls.end())
     ++EndIt;
   
@@ -2860,7 +2792,7 @@ bool ASTUnit::visitLocalTopLevelDecls(void *context, DeclVisitorFn Fn) {
     serialization::ModuleFile &
       Mod = Reader->getModuleManager().getPrimaryModule();
     ASTReader::ModuleDeclIterator MDI, MDE;
-    llvm::tie(MDI, MDE) = Reader->getModuleFileLevelDecls(Mod);
+    std::tie(MDI, MDE) = Reader->getModuleFileLevelDecls(Mod);
     for (; MDI != MDE; ++MDI) {
       if (!Fn(context, *MDI))
         return false;
@@ -2882,7 +2814,7 @@ bool ASTUnit::visitLocalTopLevelDecls(void *context, DeclVisitorFn Fn) {
 namespace {
 struct PCHLocatorInfo {
   serialization::ModuleFile *Mod;
-  PCHLocatorInfo() : Mod(0) {}
+  PCHLocatorInfo() : Mod(nullptr) {}
 };
 }
 
@@ -2905,14 +2837,14 @@ static bool PCHLocator(serialization::ModuleFile &M, void *UserData) {
 
 const FileEntry *ASTUnit::getPCHFile() {
   if (!Reader)
-    return 0;
+    return nullptr;
 
   PCHLocatorInfo Info;
   Reader->getModuleManager().visit(PCHLocator, &Info);
   if (Info.Mod)
     return Info.Mod->File;
 
-  return 0;
+  return nullptr;
 }
 
 bool ASTUnit::isModuleFile() {
@@ -2953,7 +2885,7 @@ void ASTUnit::ConcurrencyState::finish() {
 
 #else // NDEBUG
 
-ASTUnit::ConcurrencyState::ConcurrencyState() {}
+ASTUnit::ConcurrencyState::ConcurrencyState() { Mutex = 0; }
 ASTUnit::ConcurrencyState::~ConcurrencyState() {}
 void ASTUnit::ConcurrencyState::start() {}
 void ASTUnit::ConcurrencyState::finish() {}
diff --git a/lib/Frontend/CMakeLists.txt b/lib/Frontend/CMakeLists.txt
index 0566d54f36a7..403cc42927a6 100644
--- a/lib/Frontend/CMakeLists.txt
+++ b/lib/Frontend/CMakeLists.txt
@@ -1,3 +1,10 @@
+add_subdirectory(Rewrite)
+
+set(LLVM_LINK_COMPONENTS
+  Option
+  Support
+  )
+
 add_clang_library(clangFrontend
   ASTConsumers.cpp
   ASTMerge.cpp
@@ -20,6 +27,7 @@ add_clang_library(clangFrontend
   LangStandards.cpp
   LayoutOverrideSource.cpp
   LogDiagnosticPrinter.cpp
+  ModuleDependencyCollector.cpp
   MultiplexConsumer.cpp
   PrintPreprocessedOutput.cpp
   SerializedDiagnosticPrinter.cpp
@@ -27,26 +35,11 @@ add_clang_library(clangFrontend
   TextDiagnosticBuffer.cpp
   TextDiagnosticPrinter.cpp
   VerifyDiagnosticConsumer.cpp
-  Warnings.cpp
-  )
 
-add_dependencies(clangFrontend
-  ClangAttrClasses
-  ClangAttrList
-  ClangAttrParsedAttrList
-  ClangCommentNodes
-  ClangDeclNodes
-  ClangDiagnosticAST
-  ClangDiagnosticCommon
-  ClangDiagnosticDriver
-  ClangDiagnosticFrontend
-  ClangDiagnosticLex
-  ClangDiagnosticSema
+  DEPENDS
   ClangDriverOptions
-  ClangStmtNodes
-  )
 
-target_link_libraries(clangFrontend
+  LINK_LIBS
   clangAST
   clangBasic
   clangDriver
diff --git a/lib/Frontend/CacheTokens.cpp b/lib/Frontend/CacheTokens.cpp
index 0c30b049579d..14f7027e4687 100644
--- a/lib/Frontend/CacheTokens.cpp
+++ b/lib/Frontend/CacheTokens.cpp
@@ -17,14 +17,15 @@
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/FileSystemStatCache.h"
 #include "clang/Basic/IdentifierTable.h"
-#include "clang/Basic/OnDiskHashTable.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Lex/Lexer.h"
 #include "clang/Lex/Preprocessor.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringMap.h"
+#include "llvm/Support/EndianStream.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/OnDiskHashTable.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/raw_ostream.h"
 
@@ -34,12 +35,13 @@
 #endif
 
 using namespace clang;
-using namespace clang::io;
 
 //===----------------------------------------------------------------------===//
 // PTH-specific stuff.
 //===----------------------------------------------------------------------===//
 
+typedef uint32_t Offset;
+
 namespace {
 class PTHEntry {
   Offset TokenData, PPCondData;
@@ -61,13 +63,13 @@ class PTHEntryKeyVariant {
   FileData *Data;
 
 public:
-  PTHEntryKeyVariant(const FileEntry *fe) : FE(fe), Kind(IsFE), Data(0) {}
+  PTHEntryKeyVariant(const FileEntry *fe) : FE(fe), Kind(IsFE), Data(nullptr) {}
 
   PTHEntryKeyVariant(FileData *Data, const char *path)
       : Path(path), Kind(IsDE), Data(new FileData(*Data)) {}
 
   explicit PTHEntryKeyVariant(const char *path)
-      : Path(path), Kind(IsNoExist), Data(0) {}
+      : Path(path), Kind(IsNoExist), Data(nullptr) {}
 
   bool isFile() const { return Kind == IsFE; }
 
@@ -78,21 +80,23 @@ public:
   unsigned getKind() const { return (unsigned) Kind; }
 
   void EmitData(raw_ostream& Out) {
+    using namespace llvm::support;
+    endian::Writer<little> LE(Out);
     switch (Kind) {
     case IsFE: {
       // Emit stat information.
       llvm::sys::fs::UniqueID UID = FE->getUniqueID();
-      ::Emit64(Out, UID.getFile());
-      ::Emit64(Out, UID.getDevice());
-      ::Emit64(Out, FE->getModificationTime());
-      ::Emit64(Out, FE->getSize());
+      LE.write<uint64_t>(UID.getFile());
+      LE.write<uint64_t>(UID.getDevice());
+      LE.write<uint64_t>(FE->getModificationTime());
+      LE.write<uint64_t>(FE->getSize());
     } break;
     case IsDE:
       // Emit stat information.
-      ::Emit64(Out, Data->UniqueID.getFile());
-      ::Emit64(Out, Data->UniqueID.getDevice());
-      ::Emit64(Out, Data->ModTime);
-      ::Emit64(Out, Data->Size);
+      LE.write<uint64_t>(Data->UniqueID.getFile());
+      LE.write<uint64_t>(Data->UniqueID.getDevice());
+      LE.write<uint64_t>(Data->ModTime);
+      LE.write<uint64_t>(Data->Size);
       delete Data;
       break;
     default:
@@ -113,39 +117,46 @@ public:
   typedef PTHEntry data_type;
   typedef const PTHEntry& data_type_ref;
 
-  static unsigned ComputeHash(PTHEntryKeyVariant V) {
+  typedef unsigned hash_value_type;
+  typedef unsigned offset_type;
+
+  static hash_value_type ComputeHash(PTHEntryKeyVariant V) {
     return llvm::HashString(V.getString());
   }
 
   static std::pair<unsigned,unsigned>
   EmitKeyDataLength(raw_ostream& Out, PTHEntryKeyVariant V,
                     const PTHEntry& E) {
+    using namespace llvm::support;
+    endian::Writer<little> LE(Out);
 
     unsigned n = V.getString().size() + 1 + 1;
-    ::Emit16(Out, n);
+    LE.write<uint16_t>(n);
 
     unsigned m = V.getRepresentationLength() + (V.isFile() ? 4 + 4 : 0);
-    ::Emit8(Out, m);
+    LE.write<uint8_t>(m);
 
     return std::make_pair(n, m);
   }
 
   static void EmitKey(raw_ostream& Out, PTHEntryKeyVariant V, unsigned n){
+    using namespace llvm::support;
     // Emit the entry kind.
-    ::Emit8(Out, (unsigned) V.getKind());
+    endian::Writer<little>(Out).write<uint8_t>((unsigned)V.getKind());
     // Emit the string.
     Out.write(V.getString().data(), n - 1);
   }
 
   static void EmitData(raw_ostream& Out, PTHEntryKeyVariant V,
                        const PTHEntry& E, unsigned) {
-
+    using namespace llvm::support;
+    endian::Writer<little> LE(Out);
 
     // For file entries emit the offsets into the PTH file for token data
     // and the preprocessor blocks table.
     if (V.isFile()) {
-      ::Emit32(Out, E.getTokenOffset());
-      ::Emit32(Out, E.getPPCondTableOffset());
+      LE.write<uint32_t>(E.getTokenOffset());
+      LE.write<uint32_t>(E.getPPCondTableOffset());
     }
 
     // Emit any other data associated with the key (i.e., stat information).
@@ -164,7 +175,7 @@ public:
 };
 } // end anonymous namespace
 
-typedef OnDiskChainedHashTableGenerator<FileEntryPTHEntryInfo> PTHMap;
+typedef llvm::OnDiskChainedHashTableGenerator<FileEntryPTHEntryInfo> PTHMap;
 
 namespace {
 class PTHWriter {
@@ -186,18 +197,28 @@ class PTHWriter {
   /// Emit a token to the PTH file.
   void EmitToken(const Token& T);
 
-  void Emit8(uint32_t V) { ::Emit8(Out, V); }
+  void Emit8(uint32_t V) {
+    using namespace llvm::support;
+    endian::Writer<little>(Out).write<uint8_t>(V);
+  }
 
-  void Emit16(uint32_t V) { ::Emit16(Out, V); }
+  void Emit16(uint32_t V) {
+    using namespace llvm::support;
+    endian::Writer<little>(Out).write<uint16_t>(V);
+  }
 
-  void Emit32(uint32_t V) { ::Emit32(Out, V); }
+  void Emit32(uint32_t V) {
+    using namespace llvm::support;
+    endian::Writer<little>(Out).write<uint32_t>(V);
+  }
 
   void EmitBuf(const char *Ptr, unsigned NumBytes) {
     Out.write(Ptr, NumBytes);
   }
 
   void EmitString(StringRef V) {
-    ::Emit16(Out, V.size());
+    using namespace llvm::support;
+    endian::Writer<little>(Out).write<uint16_t>(V.size());
     EmitBuf(V.data(), V.size());
   }
 
@@ -270,8 +291,11 @@ void PTHWriter::EmitToken(const Token& T) {
 PTHEntry PTHWriter::LexTokens(Lexer& L) {
   // Pad 0's so that we emit tokens to a 4-byte alignment.
   // This speed up reading them back in.
-  Pad(Out, 4);
-  Offset TokenOff = (Offset) Out.tell();
+  using namespace llvm::support;
+  endian::Writer<little> LE(Out);
+  uint32_t TokenOff = Out.tell();
+  for (uint64_t N = llvm::OffsetToAlignment(TokenOff, 4); N; --N, ++TokenOff)
+    LE.write<uint8_t>(0);
 
   // Keep track of matching '#if' ... '#endif'.
   typedef std::vector<std::pair<Offset, unsigned> > PPCondTable;
@@ -293,7 +317,7 @@ PTHEntry PTHWriter::LexTokens(Lexer& L) {
       Token Tmp = Tok;
       Tmp.setKind(tok::eod);
       Tmp.clearFlag(Token::StartOfLine);
-      Tmp.setIdentifierInfo(0);
+      Tmp.setIdentifierInfo(nullptr);
       EmitToken(Tmp);
       ParsingPreprocessorDirective = false;
     }
@@ -516,8 +540,9 @@ public:
   ~StatListener() {}
 
   LookupResult getStat(const char *Path, FileData &Data, bool isFile,
-                       int *FileDescriptor) {
-    LookupResult Result = statChained(Path, Data, isFile, FileDescriptor);
+                       std::unique_ptr<vfs::File> *F,
+                       vfs::FileSystem &FS) override {
+    LookupResult Result = statChained(Path, Data, isFile, F, FS);
 
     if (Result == CacheMissing) // Failed 'stat'.
       PM.insert(PTHEntryKeyVariant(Path), PTHEntry());
@@ -578,14 +603,18 @@ public:
   typedef uint32_t  data_type;
   typedef data_type data_type_ref;
 
-  static unsigned ComputeHash(PTHIdKey* key) {
+  typedef unsigned hash_value_type;
+  typedef unsigned offset_type;
+
+  static hash_value_type ComputeHash(PTHIdKey* key) {
     return llvm::HashString(key->II->getName());
   }
 
   static std::pair<unsigned,unsigned>
   EmitKeyDataLength(raw_ostream& Out, const PTHIdKey* key, uint32_t) {
+    using namespace llvm::support;
     unsigned n = key->II->getLength() + 1;
-    ::Emit16(Out, n);
+    endian::Writer<little>(Out).write<uint16_t>(n);
     return std::make_pair(n, sizeof(uint32_t));
   }
 
@@ -598,7 +627,8 @@ public:
 
   static void EmitData(raw_ostream& Out, PTHIdKey*, uint32_t pID,
                        unsigned) {
-    ::Emit32(Out, pID);
+    using namespace llvm::support;
+    endian::Writer<little>(Out).write<uint32_t>(pID);
   }
 };
 } // end anonymous namespace
@@ -617,7 +647,7 @@ std::pair<Offset,Offset> PTHWriter::EmitIdentifierTable() {
   PTHIdKey *IIDMap = (PTHIdKey*)calloc(idcount, sizeof(PTHIdKey));
 
   // Create the hashtable.
-  OnDiskChainedHashTableGenerator<PTHIdentifierTableTrait> IIOffMap;
+  llvm::OnDiskChainedHashTableGenerator<PTHIdentifierTableTrait> IIOffMap;
 
   // Generate mapping from persistent IDs -> IdentifierInfo*.
   for (IDMap::iterator I = IM.begin(), E = IM.end(); I != E; ++I) {
diff --git a/lib/Frontend/ChainedIncludesSource.cpp b/lib/Frontend/ChainedIncludesSource.cpp
index 442177ec3197..e6e73ac963fb 100644
--- a/lib/Frontend/ChainedIncludesSource.cpp
+++ b/lib/Frontend/ChainedIncludesSource.cpp
@@ -12,7 +12,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "clang/Frontend/ChainedIncludesSource.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Frontend/ASTUnit.h"
 #include "clang/Frontend/CompilerInstance.h"
@@ -25,13 +24,61 @@
 
 using namespace clang;
 
-static ASTReader *createASTReader(CompilerInstance &CI,
-                             StringRef pchFile,
-                             SmallVectorImpl<llvm::MemoryBuffer *> &memBufs,
-                             SmallVectorImpl<std::string> &bufNames,
-                             ASTDeserializationListener *deserialListener = 0) {
+namespace {
+class ChainedIncludesSource : public ExternalSemaSource {
+public:
+  virtual ~ChainedIncludesSource();
+
+  ExternalSemaSource &getFinalReader() const { return *FinalReader; }
+
+  std::vector<CompilerInstance *> CIs;
+  IntrusiveRefCntPtr<ExternalSemaSource> FinalReader;
+
+protected:
+  //===----------------------------------------------------------------------===//
+  // ExternalASTSource interface.
+  //===----------------------------------------------------------------------===//
+
+  Decl *GetExternalDecl(uint32_t ID) override;
+  Selector GetExternalSelector(uint32_t ID) override;
+  uint32_t GetNumExternalSelectors() override;
+  Stmt *GetExternalDeclStmt(uint64_t Offset) override;
+  CXXBaseSpecifier *GetExternalCXXBaseSpecifiers(uint64_t Offset) override;
+  bool FindExternalVisibleDeclsByName(const DeclContext *DC,
+                                      DeclarationName Name) override;
+  ExternalLoadResult
+  FindExternalLexicalDecls(const DeclContext *DC,
+                           bool (*isKindWeWant)(Decl::Kind),
+                           SmallVectorImpl<Decl *> &Result) override;
+  void CompleteType(TagDecl *Tag) override;
+  void CompleteType(ObjCInterfaceDecl *Class) override;
+  void StartedDeserializing() override;
+  void FinishedDeserializing() override;
+  void StartTranslationUnit(ASTConsumer *Consumer) override;
+  void PrintStats() override;
+
+  /// Return the amount of memory used by memory buffers, breaking down
+  /// by heap-backed versus mmap'ed memory.
+  void getMemoryBufferSizes(MemoryBufferSizes &sizes) const override;
+
+  //===----------------------------------------------------------------------===//
+  // ExternalSemaSource interface.
+  //===----------------------------------------------------------------------===//
+
+  void InitializeSema(Sema &S) override;
+  void ForgetSema() override;
+  void ReadMethodPool(Selector Sel) override;
+  bool LookupUnqualified(LookupResult &R, Scope *S) override;
+};
+}
+
+static ASTReader *
+createASTReader(CompilerInstance &CI, StringRef pchFile,
+                SmallVectorImpl<llvm::MemoryBuffer *> &memBufs,
+                SmallVectorImpl<std::string> &bufNames,
+                ASTDeserializationListener *deserialListener = nullptr) {
   Preprocessor &PP = CI.getPreprocessor();
-  OwningPtr<ASTReader> Reader;
+  std::unique_ptr<ASTReader> Reader;
   Reader.reset(new ASTReader(PP, CI.getASTContext(), /*isysroot=*/"",
                              /*DisableValidation=*/true));
   for (unsigned ti = 0; ti < bufNames.size(); ++ti) {
@@ -44,7 +91,7 @@ static ASTReader *createASTReader(CompilerInstance &CI,
   case ASTReader::Success:
     // Set the predefines buffer as suggested by the PCH reader.
     PP.setPredefines(Reader->getSuggestedPredefines());
-    return Reader.take();
+    return Reader.release();
 
   case ASTReader::Failure:
   case ASTReader::Missing:
@@ -54,7 +101,7 @@ static ASTReader *createASTReader(CompilerInstance &CI,
   case ASTReader::HadErrors:
     break;
   }
-  return 0;
+  return nullptr;
 }
 
 ChainedIncludesSource::~ChainedIncludesSource() {
@@ -62,12 +109,13 @@ ChainedIncludesSource::~ChainedIncludesSource() {
     delete CIs[i];
 }
 
-ChainedIncludesSource *ChainedIncludesSource::create(CompilerInstance &CI) {
+IntrusiveRefCntPtr<ExternalSemaSource> clang::createChainedIncludesSource(
+    CompilerInstance &CI, IntrusiveRefCntPtr<ExternalSemaSource> &Reader) {
 
   std::vector<std::string> &includes = CI.getPreprocessorOpts().ChainedIncludes;
   assert(!includes.empty() && "No '-chain-include' in options!");
 
-  OwningPtr<ChainedIncludesSource> source(new ChainedIncludesSource());
+  IntrusiveRefCntPtr<ChainedIncludesSource> source(new ChainedIncludesSource());
   InputKind IK = CI.getFrontendOpts().Inputs[0].getKind();
 
   SmallVector<llvm::MemoryBuffer *, 4> serialBufs;
@@ -75,7 +123,7 @@ ChainedIncludesSource *ChainedIncludesSource::create(CompilerInstance &CI) {
 
   for (unsigned i = 0, e = includes.size(); i != e; ++i) {
     bool firstInclude = (i == 0);
-    OwningPtr<CompilerInvocation> CInvok;
+    std::unique_ptr<CompilerInvocation> CInvok;
     CInvok.reset(new CompilerInvocation(CI.getInvocation()));
     
     CInvok->getPreprocessorOpts().ChainedIncludes.clear();
@@ -96,27 +144,27 @@ ChainedIncludesSource *ChainedIncludesSource::create(CompilerInstance &CI) {
     IntrusiveRefCntPtr<DiagnosticsEngine> Diags(
         new DiagnosticsEngine(DiagID, &CI.getDiagnosticOpts(), DiagClient));
 
-    OwningPtr<CompilerInstance> Clang(new CompilerInstance());
-    Clang->setInvocation(CInvok.take());
-    Clang->setDiagnostics(Diags.getPtr());
-    Clang->setTarget(TargetInfo::CreateTargetInfo(Clang->getDiagnostics(),
-                                                  &Clang->getTargetOpts()));
+    std::unique_ptr<CompilerInstance> Clang(new CompilerInstance());
+    Clang->setInvocation(CInvok.release());
+    Clang->setDiagnostics(Diags.get());
+    Clang->setTarget(TargetInfo::CreateTargetInfo(
+        Clang->getDiagnostics(), Clang->getInvocation().TargetOpts));
     Clang->createFileManager();
     Clang->createSourceManager(Clang->getFileManager());
-    Clang->createPreprocessor();
+    Clang->createPreprocessor(TU_Prefix);
     Clang->getDiagnosticClient().BeginSourceFile(Clang->getLangOpts(),
                                                  &Clang->getPreprocessor());
     Clang->createASTContext();
 
     SmallVector<char, 256> serialAST;
     llvm::raw_svector_ostream OS(serialAST);
-    OwningPtr<ASTConsumer> consumer;
-    consumer.reset(new PCHGenerator(Clang->getPreprocessor(), "-", 0,
+    std::unique_ptr<ASTConsumer> consumer;
+    consumer.reset(new PCHGenerator(Clang->getPreprocessor(), "-", nullptr,
                                     /*isysroot=*/"", &OS));
     Clang->getASTContext().setASTMutationListener(
                                             consumer->GetASTMutationListener());
-    Clang->setASTConsumer(consumer.take());
-    Clang->createSema(TU_Prefix, 0);
+    Clang->setASTConsumer(consumer.release());
+    Clang->createSema(TU_Prefix, nullptr);
 
     if (firstInclude) {
       Preprocessor &PP = Clang->getPreprocessor();
@@ -125,50 +173,42 @@ ChainedIncludesSource *ChainedIncludesSource::create(CompilerInstance &CI) {
     } else {
       assert(!serialBufs.empty());
       SmallVector<llvm::MemoryBuffer *, 4> bufs;
-      for (unsigned si = 0, se = serialBufs.size(); si != se; ++si) {
-        bufs.push_back(llvm::MemoryBuffer::getMemBufferCopy(
-                             StringRef(serialBufs[si]->getBufferStart(),
-                                             serialBufs[si]->getBufferSize())));
-      }
+      // TODO: Pass through the existing MemoryBuffer instances instead of
+      // allocating new ones.
+      for (auto *SB : serialBufs)
+        bufs.push_back(llvm::MemoryBuffer::getMemBuffer(SB->getBuffer()));
       std::string pchName = includes[i-1];
       llvm::raw_string_ostream os(pchName);
       os << ".pch" << i-1;
-      os.flush();
-      
-      serialBufNames.push_back(pchName);
-
-      OwningPtr<ExternalASTSource> Reader;
+      serialBufNames.push_back(os.str());
 
-      Reader.reset(createASTReader(*Clang, pchName, bufs, serialBufNames, 
-        Clang->getASTConsumer().GetASTDeserializationListener()));
+      IntrusiveRefCntPtr<ASTReader> Reader;
+      Reader = createASTReader(*Clang, pchName, bufs, serialBufNames, 
+        Clang->getASTConsumer().GetASTDeserializationListener());
       if (!Reader)
-        return 0;
-      Clang->setModuleManager(static_cast<ASTReader*>(Reader.get()));
+        return nullptr;
+      Clang->setModuleManager(Reader);
       Clang->getASTContext().setExternalSource(Reader);
     }
     
     if (!Clang->InitializeSourceManager(InputFile))
-      return 0;
+      return nullptr;
 
     ParseAST(Clang->getSema());
-    OS.flush();
     Clang->getDiagnosticClient().EndSourceFile();
-    serialBufs.push_back(
-      llvm::MemoryBuffer::getMemBufferCopy(StringRef(serialAST.data(),
-                                                           serialAST.size())));
-    source->CIs.push_back(Clang.take());
+    serialBufs.push_back(llvm::MemoryBuffer::getMemBufferCopy(OS.str()));
+    source->CIs.push_back(Clang.release());
   }
 
   assert(!serialBufs.empty());
   std::string pchName = includes.back() + ".pch-final";
   serialBufNames.push_back(pchName);
-  OwningPtr<ASTReader> Reader;
-  Reader.reset(createASTReader(CI, pchName, serialBufs, serialBufNames));
+  Reader = createASTReader(CI, pchName, serialBufs, serialBufNames);
   if (!Reader)
-    return 0;
+    return nullptr;
 
-  source->FinalReader.reset(Reader.take());
-  return source.take();
+  source->FinalReader = Reader;
+  return source;
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/lib/Frontend/CompilerInstance.cpp b/lib/Frontend/CompilerInstance.cpp
index eccb94cc4a4f..6af920d9fd78 100644
--- a/lib/Frontend/CompilerInstance.cpp
+++ b/lib/Frontend/CompilerInstance.cpp
@@ -16,6 +16,7 @@
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Basic/Version.h"
+#include "clang/Config/config.h"
 #include "clang/Frontend/ChainedDiagnosticConsumer.h"
 #include "clang/Frontend/FrontendAction.h"
 #include "clang/Frontend/FrontendActions.h"
@@ -31,9 +32,10 @@
 #include "clang/Sema/CodeCompleteConsumer.h"
 #include "clang/Sema/Sema.h"
 #include "clang/Serialization/ASTReader.h"
+#include "clang/Serialization/GlobalModuleIndex.h"
 #include "llvm/ADT/Statistic.h"
-#include "llvm/Config/config.h"
 #include "llvm/Support/CrashRecoveryContext.h"
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/LockFileManager.h"
@@ -43,15 +45,17 @@
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/raw_ostream.h"
-#include "llvm/Support/system_error.h"
 #include <sys/stat.h>
+#include <system_error>
 #include <time.h>
 
 using namespace clang;
 
-CompilerInstance::CompilerInstance()
-  : Invocation(new CompilerInvocation()), ModuleManager(0),
-    BuildGlobalModuleIndex(false), ModuleBuildFailed(false) {
+CompilerInstance::CompilerInstance(bool BuildingModule)
+  : ModuleLoader(BuildingModule),
+    Invocation(new CompilerInvocation()), ModuleManager(nullptr),
+    BuildGlobalModuleIndex(false), HaveFullGlobalModuleIndex(false),
+    ModuleBuildFailed(false) {
 }
 
 CompilerInstance::~CompilerInstance() {
@@ -79,6 +83,10 @@ void CompilerInstance::setTarget(TargetInfo *Value) {
 
 void CompilerInstance::setFileManager(FileManager *Value) {
   FileMgr = Value;
+  if (Value)
+    VirtualFileSystem = Value->getVirtualFileSystem();
+  else
+    VirtualFileSystem.reset();
 }
 
 void CompilerInstance::setSourceManager(SourceManager *Value) {
@@ -100,6 +108,23 @@ void CompilerInstance::setASTConsumer(ASTConsumer *Value) {
 void CompilerInstance::setCodeCompletionConsumer(CodeCompleteConsumer *Value) {
   CompletionConsumer.reset(Value);
 }
+ 
+IntrusiveRefCntPtr<ASTReader> CompilerInstance::getModuleManager() const {
+  return ModuleManager;
+}
+void CompilerInstance::setModuleManager(IntrusiveRefCntPtr<ASTReader> Reader) {
+  ModuleManager = Reader;
+}
+
+std::shared_ptr<ModuleDependencyCollector>
+CompilerInstance::getModuleDepCollector() const {
+  return ModuleDepCollector;
+}
+
+void CompilerInstance::setModuleDepCollector(
+    std::shared_ptr<ModuleDependencyCollector> Collector) {
+  ModuleDepCollector = Collector;
+}
 
 // Diagnostics
 static void SetUpDiagnosticLog(DiagnosticOptions *DiagOpts,
@@ -110,9 +135,9 @@ static void SetUpDiagnosticLog(DiagnosticOptions *DiagOpts,
   raw_ostream *OS = &llvm::errs();
   if (DiagOpts->DiagnosticLogFile != "-") {
     // Create the output stream.
-    llvm::raw_fd_ostream *FileOS(
-        new llvm::raw_fd_ostream(DiagOpts->DiagnosticLogFile.c_str(), ErrorInfo,
-                                 llvm::sys::fs::F_Append));
+    llvm::raw_fd_ostream *FileOS(new llvm::raw_fd_ostream(
+        DiagOpts->DiagnosticLogFile.c_str(), ErrorInfo,
+        llvm::sys::fs::F_Append | llvm::sys::fs::F_Text));
     if (!ErrorInfo.empty()) {
       Diags.Report(diag::warn_fe_cc_log_diagnostics_failure)
         << DiagOpts->DiagnosticLogFile << ErrorInfo;
@@ -136,20 +161,19 @@ static void SetupSerializedDiagnostics(DiagnosticOptions *DiagOpts,
                                        DiagnosticsEngine &Diags,
                                        StringRef OutputFile) {
   std::string ErrorInfo;
-  OwningPtr<llvm::raw_fd_ostream> OS;
+  std::unique_ptr<llvm::raw_fd_ostream> OS;
   OS.reset(new llvm::raw_fd_ostream(OutputFile.str().c_str(), ErrorInfo,
-                                    llvm::sys::fs::F_Binary));
+                                    llvm::sys::fs::F_None));
 
   if (!ErrorInfo.empty()) {
     Diags.Report(diag::warn_fe_serialized_diag_failure)
       << OutputFile << ErrorInfo;
     return;
   }
-  
+
   DiagnosticConsumer *SerializedConsumer =
-    clang::serialized_diags::create(OS.take(), DiagOpts);
+      clang::serialized_diags::create(OS.release(), DiagOpts);
 
-  
   Diags.setClient(new ChainedDiagnosticConsumer(Diags.takeClient(),
                                                 SerializedConsumer));
 }
@@ -197,7 +221,11 @@ CompilerInstance::createDiagnostics(DiagnosticOptions *Opts,
 // File Manager
 
 void CompilerInstance::createFileManager() {
-  FileMgr = new FileManager(getFileSystemOpts());
+  if (!hasVirtualFileSystem()) {
+    // TODO: choose the virtual file system based on the CompilerInvocation.
+    setVirtualFileSystem(vfs::getRealFileSystem());
+  }
+  FileMgr = new FileManager(getFileSystemOpts(), VirtualFileSystem);
 }
 
 // Source Manager
@@ -206,13 +234,63 @@ void CompilerInstance::createSourceManager(FileManager &FileMgr) {
   SourceMgr = new SourceManager(getDiagnostics(), FileMgr);
 }
 
+// Initialize the remapping of files to alternative contents, e.g.,
+// those specified through other files.
+static void InitializeFileRemapping(DiagnosticsEngine &Diags,
+                                    SourceManager &SourceMgr,
+                                    FileManager &FileMgr,
+                                    const PreprocessorOptions &InitOpts) {
+  // Remap files in the source manager (with buffers).
+  for (const auto &RB : InitOpts.RemappedFileBuffers) {
+    // Create the file entry for the file that we're mapping from.
+    const FileEntry *FromFile =
+        FileMgr.getVirtualFile(RB.first, RB.second->getBufferSize(), 0);
+    if (!FromFile) {
+      Diags.Report(diag::err_fe_remap_missing_from_file) << RB.first;
+      if (!InitOpts.RetainRemappedFileBuffers)
+        delete RB.second;
+      continue;
+    }
+
+    // Override the contents of the "from" file with the contents of
+    // the "to" file.
+    SourceMgr.overrideFileContents(FromFile, RB.second,
+                                   InitOpts.RetainRemappedFileBuffers);
+  }
+
+  // Remap files in the source manager (with other files).
+  for (const auto &RF : InitOpts.RemappedFiles) {
+    // Find the file that we're mapping to.
+    const FileEntry *ToFile = FileMgr.getFile(RF.second);
+    if (!ToFile) {
+      Diags.Report(diag::err_fe_remap_missing_to_file) << RF.first << RF.second;
+      continue;
+    }
+
+    // Create the file entry for the file that we're mapping from.
+    const FileEntry *FromFile =
+        FileMgr.getVirtualFile(RF.first, ToFile->getSize(), 0);
+    if (!FromFile) {
+      Diags.Report(diag::err_fe_remap_missing_from_file) << RF.first;
+      continue;
+    }
+
+    // Override the contents of the "from" file with the contents of
+    // the "to" file.
+    SourceMgr.overrideFileContents(FromFile, ToFile);
+  }
+
+  SourceMgr.setOverridenFilesKeepOriginalName(
+      InitOpts.RemappedFilesKeepOriginalName);
+}
+
 // Preprocessor
 
-void CompilerInstance::createPreprocessor() {
+void CompilerInstance::createPreprocessor(TranslationUnitKind TUKind) {
   const PreprocessorOptions &PPOpts = getPreprocessorOpts();
 
   // Create a PTH manager if we are using some form of a token cache.
-  PTHManager *PTHMgr = 0;
+  PTHManager *PTHMgr = nullptr;
   if (!PPOpts.TokenCache.empty())
     PTHMgr = PTHManager::Create(PPOpts.TokenCache, getDiagnostics());
 
@@ -222,10 +300,10 @@ void CompilerInstance::createPreprocessor() {
                                               getDiagnostics(),
                                               getLangOpts(),
                                               &getTarget());
-  PP = new Preprocessor(&getPreprocessorOpts(),
-                        getDiagnostics(), getLangOpts(), &getTarget(),
+  PP = new Preprocessor(&getPreprocessorOpts(), getDiagnostics(), getLangOpts(),
                         getSourceManager(), *HeaderInfo, *this, PTHMgr,
-                        /*OwnsHeaderSearch=*/true);
+                        /*OwnsHeaderSearch=*/true, TUKind);
+  PP->Initialize(getTarget());
 
   // Note that this is different then passing PTHMgr to Preprocessor's ctor.
   // That argument is used as the IdentifierInfoLookup argument to
@@ -238,7 +316,16 @@ void CompilerInstance::createPreprocessor() {
   if (PPOpts.DetailedRecord)
     PP->createPreprocessingRecord();
 
-  InitializePreprocessor(*PP, PPOpts, getHeaderSearchOpts(), getFrontendOpts());
+  // Apply remappings to the source manager.
+  InitializeFileRemapping(PP->getDiagnostics(), PP->getSourceManager(),
+                          PP->getFileManager(), PPOpts);
+
+  // Predefine macros and configure the preprocessor.
+  InitializePreprocessor(*PP, PPOpts, getFrontendOpts());
+
+  // Initialize the header search object.
+  ApplyHeaderSearchOptions(PP->getHeaderSearchInfo(), getHeaderSearchOpts(),
+                           PP->getLangOpts(), PP->getTargetInfo().getTriple());
 
   PP->setPreprocessedOutput(getPreprocessorOutputOpts().ShowCPP);
 
@@ -254,11 +341,20 @@ void CompilerInstance::createPreprocessor() {
   // Handle generating dependencies, if requested.
   const DependencyOutputOptions &DepOpts = getDependencyOutputOpts();
   if (!DepOpts.OutputFile.empty())
-    AttachDependencyFileGen(*PP, DepOpts);
+    TheDependencyFileGenerator.reset(
+        DependencyFileGenerator::CreateAndAttachToPreprocessor(*PP, DepOpts));
   if (!DepOpts.DOTOutputFile.empty())
     AttachDependencyGraphGen(*PP, DepOpts.DOTOutputFile,
                              getHeaderSearchOpts().Sysroot);
 
+  for (auto &Listener : DependencyCollectors)
+    Listener->attachToPreprocessor(*PP);
+
+  // If we don't have a collector, but we are collecting module dependencies,
+  // then we're the top level compiler instance and need to create one.
+  if (!ModuleDepCollector && !DepOpts.ModuleDependencyOutputDir.empty())
+    ModuleDepCollector = std::make_shared<ModuleDependencyCollector>(
+        DepOpts.ModuleDependencyOutputDir);
 
   // Handle generating header include information, if requested.
   if (DepOpts.ShowHeaderIncludes)
@@ -282,49 +378,46 @@ void CompilerInstance::createPreprocessor() {
 void CompilerInstance::createASTContext() {
   Preprocessor &PP = getPreprocessor();
   Context = new ASTContext(getLangOpts(), PP.getSourceManager(),
-                           &getTarget(), PP.getIdentifierTable(),
-                           PP.getSelectorTable(), PP.getBuiltinInfo(),
-                           /*size_reserve=*/ 0);
+                           PP.getIdentifierTable(), PP.getSelectorTable(),
+                           PP.getBuiltinInfo());
+  Context->InitBuiltinTypes(getTarget());
 }
 
 // ExternalASTSource
 
-void CompilerInstance::createPCHExternalASTSource(StringRef Path,
-                                                  bool DisablePCHValidation,
-                                                bool AllowPCHWithCompilerErrors,
-                                                 void *DeserializationListener){
-  OwningPtr<ExternalASTSource> Source;
+void CompilerInstance::createPCHExternalASTSource(
+    StringRef Path, bool DisablePCHValidation, bool AllowPCHWithCompilerErrors,
+    void *DeserializationListener, bool OwnDeserializationListener) {
+  IntrusiveRefCntPtr<ExternalASTSource> Source;
   bool Preamble = getPreprocessorOpts().PrecompiledPreambleBytes.first != 0;
-  Source.reset(createPCHExternalASTSource(Path, getHeaderSearchOpts().Sysroot,
-                                          DisablePCHValidation,
-                                          AllowPCHWithCompilerErrors,
-                                          getPreprocessor(), getASTContext(),
-                                          DeserializationListener,
-                                          Preamble,
-                                       getFrontendOpts().UseGlobalModuleIndex));
+  Source = createPCHExternalASTSource(
+      Path, getHeaderSearchOpts().Sysroot, DisablePCHValidation,
+      AllowPCHWithCompilerErrors, getPreprocessor(), getASTContext(),
+      DeserializationListener, OwnDeserializationListener, Preamble,
+      getFrontendOpts().UseGlobalModuleIndex);
   ModuleManager = static_cast<ASTReader*>(Source.get());
   getASTContext().setExternalSource(Source);
 }
 
-ExternalASTSource *
-CompilerInstance::createPCHExternalASTSource(StringRef Path,
-                                             const std::string &Sysroot,
-                                             bool DisablePCHValidation,
-                                             bool AllowPCHWithCompilerErrors,
-                                             Preprocessor &PP,
-                                             ASTContext &Context,
-                                             void *DeserializationListener,
-                                             bool Preamble,
-                                             bool UseGlobalModuleIndex) {
-  OwningPtr<ASTReader> Reader;
+ExternalASTSource *CompilerInstance::createPCHExternalASTSource(
+    StringRef Path, const std::string &Sysroot, bool DisablePCHValidation,
+    bool AllowPCHWithCompilerErrors, Preprocessor &PP, ASTContext &Context,
+    void *DeserializationListener, bool OwnDeserializationListener,
+    bool Preamble, bool UseGlobalModuleIndex) {
+  HeaderSearchOptions &HSOpts = PP.getHeaderSearchInfo().getHeaderSearchOpts();
+
+  std::unique_ptr<ASTReader> Reader;
   Reader.reset(new ASTReader(PP, Context,
                              Sysroot.empty() ? "" : Sysroot.c_str(),
                              DisablePCHValidation,
                              AllowPCHWithCompilerErrors,
+                             /*AllowConfigurationMismatch*/false,
+                             HSOpts.ModulesValidateSystemHeaders,
                              UseGlobalModuleIndex));
 
   Reader->setDeserializationListener(
-            static_cast<ASTDeserializationListener *>(DeserializationListener));
+      static_cast<ASTDeserializationListener *>(DeserializationListener),
+      /*TakeOwnership=*/OwnDeserializationListener);
   switch (Reader->ReadAST(Path,
                           Preamble ? serialization::MK_Preamble
                                    : serialization::MK_PCH,
@@ -334,7 +427,7 @@ CompilerInstance::createPCHExternalASTSource(StringRef Path,
     // Set the predefines buffer as suggested by the PCH reader. Typically, the
     // predefines buffer will be empty.
     PP.setPredefines(Reader->getSuggestedPredefines());
-    return Reader.take();
+    return Reader.release();
 
   case ASTReader::Failure:
     // Unrecoverable failure: don't even try to process the input file.
@@ -349,7 +442,7 @@ CompilerInstance::createPCHExternalASTSource(StringRef Path,
     break;
   }
 
-  return 0;
+  return nullptr;
 }
 
 // Code Completion
@@ -384,14 +477,14 @@ void CompilerInstance::createCodeCompletionConsumer() {
       return;
   } else if (EnableCodeCompletion(getPreprocessor(), Loc.FileName,
                                   Loc.Line, Loc.Column)) {
-    setCodeCompletionConsumer(0);
+    setCodeCompletionConsumer(nullptr);
     return;
   }
 
   if (CompletionConsumer->isOutputBinary() &&
       llvm::sys::ChangeStdoutToBinary()) {
     getPreprocessor().getDiagnostics().Report(diag::err_fe_stdout_binary);
-    setCodeCompletionConsumer(0);
+    setCodeCompletionConsumer(nullptr);
   }
 }
 
@@ -407,7 +500,7 @@ CompilerInstance::createCodeCompletionConsumer(Preprocessor &PP,
                                                const CodeCompleteOptions &Opts,
                                                raw_ostream &OS) {
   if (EnableCodeCompletion(PP, Filename, Line, Column))
-    return 0;
+    return nullptr;
 
   // Set up the creation routine for code-completion.
   return new PrintingCodeCompleteConsumer(Opts, OS);
@@ -432,21 +525,19 @@ void CompilerInstance::clearOutputFiles(bool EraseFiles) {
     delete it->OS;
     if (!it->TempFilename.empty()) {
       if (EraseFiles) {
-        bool existed;
-        llvm::sys::fs::remove(it->TempFilename, existed);
+        llvm::sys::fs::remove(it->TempFilename);
       } else {
         SmallString<128> NewOutFile(it->Filename);
 
         // If '-working-directory' was passed, the output filename should be
         // relative to that.
         FileMgr->FixupRelativePath(NewOutFile);
-        if (llvm::error_code ec = llvm::sys::fs::rename(it->TempFilename,
-                                                        NewOutFile.str())) {
+        if (std::error_code ec =
+                llvm::sys::fs::rename(it->TempFilename, NewOutFile.str())) {
           getDiagnostics().Report(diag::err_unable_to_rename_temp)
             << it->TempFilename << it->Filename << ec.message();
 
-          bool existed;
-          llvm::sys::fs::remove(it->TempFilename, existed);
+          llvm::sys::fs::remove(it->TempFilename);
         }
       }
     } else if (!it->Filename.empty() && EraseFiles)
@@ -465,6 +556,12 @@ CompilerInstance::createDefaultOutputFile(bool Binary,
                           /*UseTemporary=*/true);
 }
 
+llvm::raw_null_ostream *CompilerInstance::createNullOutputFile() {
+  llvm::raw_null_ostream *OS = new llvm::raw_null_ostream();
+  addOutputFile(OutputFile("", "", OS));
+  return OS;
+}
+
 llvm::raw_fd_ostream *
 CompilerInstance::createOutputFile(StringRef OutputPath,
                                    bool Binary, bool RemoveFileOnSignal,
@@ -483,7 +580,7 @@ CompilerInstance::createOutputFile(StringRef OutputPath,
   if (!OS) {
     getDiagnostics().Report(diag::err_fe_unable_to_open_output)
       << OutputPath << Error;
-    return 0;
+    return nullptr;
   }
 
   // Add the output file -- but don't try to remove "-", since this means we are
@@ -521,7 +618,7 @@ CompilerInstance::createOutputFile(StringRef OutputPath,
     OutFile = "-";
   }
 
-  OwningPtr<llvm::raw_fd_ostream> OS;
+  std::unique_ptr<llvm::raw_fd_ostream> OS;
   std::string OSFile;
 
   if (UseTemporary) {
@@ -533,7 +630,7 @@ CompilerInstance::createOutputFile(StringRef OutputPath,
       if (llvm::sys::fs::exists(Status)) {
         // Fail early if we can't write to the final destination.
         if (!llvm::sys::fs::can_write(OutputPath))
-          return 0;
+          return nullptr;
 
         // Don't use a temporary if the output is a special file. This handles
         // things like '-o /dev/null'
@@ -549,7 +646,7 @@ CompilerInstance::createOutputFile(StringRef OutputPath,
     TempPath = OutFile;
     TempPath += "-%%%%%%%%";
     int fd;
-    llvm::error_code EC =
+    std::error_code EC =
         llvm::sys::fs::createUniqueFile(TempPath.str(), fd, TempPath);
 
     if (CreateMissingDirectories &&
@@ -574,9 +671,9 @@ CompilerInstance::createOutputFile(StringRef OutputPath,
     OSFile = OutFile;
     OS.reset(new llvm::raw_fd_ostream(
         OSFile.c_str(), Error,
-        (Binary ? llvm::sys::fs::F_Binary : llvm::sys::fs::F_None)));
+        (Binary ? llvm::sys::fs::F_None : llvm::sys::fs::F_Text)));
     if (!Error.empty())
-      return 0;
+      return nullptr;
   }
 
   // Make sure the out stream file gets removed if we crash.
@@ -588,7 +685,7 @@ CompilerInstance::createOutputFile(StringRef OutputPath,
   if (TempPathName)
     *TempPathName = TempFile;
 
-  return OS.take();
+  return OS.release();
 }
 
 // Initialization Utilities
@@ -608,7 +705,7 @@ bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input,
     Kind = Input.isSystem() ? SrcMgr::C_System : SrcMgr::C_User;
 
   if (Input.isBuffer()) {
-    SourceMgr.createMainFileIDForMemBuffer(Input.getBuffer(), Kind);
+    SourceMgr.setMainFileID(SourceMgr.createFileID(Input.getBuffer(), Kind));
     assert(!SourceMgr.getMainFileID().isInvalid() &&
            "Couldn't establish MainFileID!");
     return true;
@@ -642,17 +739,22 @@ bool CompilerInstance::InitializeSourceManager(const FrontendInputFile &Input,
       }
     }
 
-    SourceMgr.createMainFileID(File, Kind);
+    SourceMgr.setMainFileID(
+        SourceMgr.createFileID(File, SourceLocation(), Kind));
   } else {
-    OwningPtr<llvm::MemoryBuffer> SB;
-    if (llvm::error_code ec = llvm::MemoryBuffer::getSTDIN(SB)) {
-      Diags.Report(diag::err_fe_error_reading_stdin) << ec.message();
+    llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> SBOrErr =
+        llvm::MemoryBuffer::getSTDIN();
+    if (std::error_code EC = SBOrErr.getError()) {
+      Diags.Report(diag::err_fe_error_reading_stdin) << EC.message();
       return false;
     }
+    std::unique_ptr<llvm::MemoryBuffer> SB = std::move(SBOrErr.get());
+
     const FileEntry *File = FileMgr.getVirtualFile(SB->getBufferIdentifier(),
                                                    SB->getBufferSize(), 0);
-    SourceMgr.createMainFileID(File, Kind);
-    SourceMgr.overrideFileContents(File, SB.take());
+    SourceMgr.setMainFileID(
+        SourceMgr.createFileID(File, SourceLocation(), Kind));
+    SourceMgr.overrideFileContents(File, SB.release());
   }
 
   assert(!SourceMgr.getMainFileID().isInvalid() &&
@@ -672,7 +774,8 @@ bool CompilerInstance::ExecuteAction(FrontendAction &Act) {
   raw_ostream &OS = llvm::errs();
 
   // Create the target instance.
-  setTarget(TargetInfo::CreateTargetInfo(getDiagnostics(), &getTargetOpts()));
+  setTarget(TargetInfo::CreateTargetInfo(getDiagnostics(),
+                                         getInvocation().TargetOpts));
   if (!hasTarget())
     return false;
 
@@ -680,7 +783,7 @@ bool CompilerInstance::ExecuteAction(FrontendAction &Act) {
   //
   // FIXME: We shouldn't need to do this, the target should be immutable once
   // created. This complexity should be lifted elsewhere.
-  getTarget().setForcedLangOptions(getLangOpts());
+  getTarget().adjust(getLangOpts());
 
   // rewriter project will change target built-in bool type from its default. 
   if (getFrontendOpts().ProgramAction == frontend::RewriteObjC)
@@ -689,7 +792,7 @@ bool CompilerInstance::ExecuteAction(FrontendAction &Act) {
   // Validate/process some options.
   if (getHeaderSearchOpts().Verbose)
     OS << "clang -cc1 version " CLANG_VERSION_STRING
-       << " based upon " << PACKAGE_STRING
+       << " based upon " << BACKEND_PACKAGE_STRING
        << " default target " << llvm::sys::getDefaultTargetTriple() << "\n";
 
   if (getFrontendOpts().ShowTimers)
@@ -748,65 +851,13 @@ static InputKind getSourceInputKindFromOptions(const LangOptions &LangOpts) {
   return LangOpts.CPlusPlus? IK_CXX : IK_C;
 }
 
-namespace {
-  struct CompileModuleMapData {
-    CompilerInstance &Instance;
-    GenerateModuleAction &CreateModuleAction;
-  };
-}
-
-/// \brief Helper function that executes the module-generating action under
-/// a crash recovery context.
-static void doCompileMapModule(void *UserData) {
-  CompileModuleMapData &Data
-    = *reinterpret_cast<CompileModuleMapData *>(UserData);
-  Data.Instance.ExecuteAction(Data.CreateModuleAction);
-}
-
-namespace {
-  /// \brief Function object that checks with the given macro definition should
-  /// be removed, because it is one of the ignored macros.
-  class RemoveIgnoredMacro {
-    const HeaderSearchOptions &HSOpts;
-
-  public:
-    explicit RemoveIgnoredMacro(const HeaderSearchOptions &HSOpts)
-      : HSOpts(HSOpts) { }
-
-    bool operator()(const std::pair<std::string, bool> &def) const {
-      StringRef MacroDef = def.first;
-      return HSOpts.ModulesIgnoreMacros.count(MacroDef.split('=').first) > 0;
-    }
-  };
-}
-
 /// \brief Compile a module file for the given module, using the options 
-/// provided by the importing compiler instance.
-static void compileModule(CompilerInstance &ImportingInstance,
-                          SourceLocation ImportLoc,
-                          Module *Module,
-                          StringRef ModuleFileName) {
-  // FIXME: have LockFileManager return an error_code so that we can
-  // avoid the mkdir when the directory already exists.
-  StringRef Dir = llvm::sys::path::parent_path(ModuleFileName);
-  llvm::sys::fs::create_directories(Dir);
-
-  llvm::LockFileManager Locked(ModuleFileName);
-  switch (Locked) {
-  case llvm::LockFileManager::LFS_Error:
-    return;
-
-  case llvm::LockFileManager::LFS_Owned:
-    // We're responsible for building the module ourselves. Do so below.
-    break;
-
-  case llvm::LockFileManager::LFS_Shared:
-    // Someone else is responsible for building the module. Wait for them to
-    // finish.
-    Locked.waitForUnlock();
-    return;
-  }
-
+/// provided by the importing compiler instance. Returns true if the module
+/// was built without errors.
+static bool compileModuleImpl(CompilerInstance &ImportingInstance,
+                              SourceLocation ImportLoc,
+                              Module *Module,
+                              StringRef ModuleFileName) {
   ModuleMap &ModMap 
     = ImportingInstance.getPreprocessor().getHeaderSearchInfo().getModuleMap();
     
@@ -824,10 +875,13 @@ static void compileModule(CompilerInstance &ImportingInstance,
   // Remove any macro definitions that are explicitly ignored by the module.
   // They aren't supposed to affect how the module is built anyway.
   const HeaderSearchOptions &HSOpts = Invocation->getHeaderSearchOpts();
-  PPOpts.Macros.erase(std::remove_if(PPOpts.Macros.begin(), PPOpts.Macros.end(),
-                                     RemoveIgnoredMacro(HSOpts)),
-                      PPOpts.Macros.end());
-
+  PPOpts.Macros.erase(
+      std::remove_if(PPOpts.Macros.begin(), PPOpts.Macros.end(),
+                     [&HSOpts](const std::pair<std::string, bool> &def) {
+        StringRef MacroDef = def.first;
+        return HSOpts.ModulesIgnoreMacros.count(MacroDef.split('=').first) > 0;
+      }),
+      PPOpts.Macros.end());
 
   // Note the name of the module we're building.
   Invocation->getLangOpts()->CurrentModule = Module->getTopLevelModuleName();
@@ -860,16 +914,18 @@ static void compileModule(CompilerInstance &ImportingInstance,
   
   // Construct a compiler instance that will be used to actually create the
   // module.
-  CompilerInstance Instance;
+  CompilerInstance Instance(/*BuildingModule=*/true);
   Instance.setInvocation(&*Invocation);
 
   Instance.createDiagnostics(new ForwardingDiagnosticConsumer(
                                    ImportingInstance.getDiagnosticClient()),
                              /*ShouldOwnClient=*/true);
 
+  Instance.setVirtualFileSystem(&ImportingInstance.getVirtualFileSystem());
+
   // Note that this module is part of the module build stack, so that we
   // can detect cycles in the module graph.
-  Instance.createFileManager(); // FIXME: Adopt file manager from importer?
+  Instance.setFileManager(&ImportingInstance.getFileManager());
   Instance.createSourceManager(Instance.getFileManager());
   SourceManager &SourceMgr = Instance.getSourceManager();
   SourceMgr.setModuleBuildStack(
@@ -877,6 +933,10 @@ static void compileModule(CompilerInstance &ImportingInstance,
   SourceMgr.pushModuleBuildStack(Module->getTopLevelModuleName(),
     FullSourceLoc(ImportLoc, ImportingInstance.getSourceManager()));
 
+  // If we're collecting module dependencies, we need to share a collector
+  // between all of the module CompilerInstances.
+  Instance.setModuleDepCollector(ImportingInstance.getModuleDepCollector());
+
   // Get or create the module map that we'll use to build this module.
   std::string InferredModuleMapContent;
   if (const FileEntry *ModuleMapFile =
@@ -891,24 +951,24 @@ static void compileModule(CompilerInstance &ImportingInstance,
     FrontendOpts.Inputs.push_back(
         FrontendInputFile("__inferred_module.map", IK));
 
-    const llvm::MemoryBuffer *ModuleMapBuffer =
+    llvm::MemoryBuffer *ModuleMapBuffer =
         llvm::MemoryBuffer::getMemBuffer(InferredModuleMapContent);
     ModuleMapFile = Instance.getFileManager().getVirtualFile(
         "__inferred_module.map", InferredModuleMapContent.size(), 0);
     SourceMgr.overrideFileContents(ModuleMapFile, ModuleMapBuffer);
   }
 
-  // Construct a module-generating action.
-  GenerateModuleAction CreateModuleAction(Module->IsSystem);
+  // Construct a module-generating action. Passing through Module->ModuleMap is
+  // safe because the FileManager is shared between the compiler instances.
+  GenerateModuleAction CreateModuleAction(Module->ModuleMap, Module->IsSystem);
   
   // Execute the action to actually build the module in-place. Use a separate
   // thread so that we get a stack large enough.
   const unsigned ThreadStackSize = 8 << 20;
   llvm::CrashRecoveryContext CRC;
-  CompileModuleMapData Data = { Instance, CreateModuleAction };
-  CRC.RunSafelyOnThread(&doCompileMapModule, &Data, ThreadStackSize);
+  CRC.RunSafelyOnThread([&]() { Instance.ExecuteAction(CreateModuleAction); },
+                        ThreadStackSize);
 
-  
   // Delete the temporary module map file.
   // FIXME: Even though we're executing under crash protection, it would still
   // be nice to do this with RemoveFileOnSignal when we can. However, that
@@ -920,6 +980,67 @@ static void compileModule(CompilerInstance &ImportingInstance,
   if (ImportingInstance.getFrontendOpts().GenerateGlobalModuleIndex) {
     ImportingInstance.setBuildGlobalModuleIndex(true);
   }
+
+  return !Instance.getDiagnostics().hasErrorOccurred();
+}
+
+static bool compileAndLoadModule(CompilerInstance &ImportingInstance,
+                                 SourceLocation ImportLoc,
+                                 SourceLocation ModuleNameLoc, Module *Module,
+                                 StringRef ModuleFileName) {
+  auto diagnoseBuildFailure = [&] {
+    ImportingInstance.getDiagnostics().Report(ModuleNameLoc,
+                                              diag::err_module_not_built)
+        << Module->Name << SourceRange(ImportLoc, ModuleNameLoc);
+  };
+
+  // FIXME: have LockFileManager return an error_code so that we can
+  // avoid the mkdir when the directory already exists.
+  StringRef Dir = llvm::sys::path::parent_path(ModuleFileName);
+  llvm::sys::fs::create_directories(Dir);
+
+  while (1) {
+    unsigned ModuleLoadCapabilities = ASTReader::ARR_Missing;
+    llvm::LockFileManager Locked(ModuleFileName);
+    switch (Locked) {
+    case llvm::LockFileManager::LFS_Error:
+      return false;
+
+    case llvm::LockFileManager::LFS_Owned:
+      // We're responsible for building the module ourselves.
+      if (!compileModuleImpl(ImportingInstance, ModuleNameLoc, Module,
+                             ModuleFileName)) {
+        diagnoseBuildFailure();
+        return false;
+      }
+      break;
+
+    case llvm::LockFileManager::LFS_Shared:
+      // Someone else is responsible for building the module. Wait for them to
+      // finish.
+      if (Locked.waitForUnlock() == llvm::LockFileManager::Res_OwnerDied)
+        continue; // try again to get the lock.
+      ModuleLoadCapabilities |= ASTReader::ARR_OutOfDate;
+      break;
+    }
+
+    // Try to read the module file, now that we've compiled it.
+    ASTReader::ASTReadResult ReadResult =
+        ImportingInstance.getModuleManager()->ReadAST(
+            ModuleFileName, serialization::MK_Module, ImportLoc,
+            ModuleLoadCapabilities);
+
+    if (ReadResult == ASTReader::OutOfDate &&
+        Locked == llvm::LockFileManager::LFS_Shared) {
+      // The module may be out of date in the presence of file system races,
+      // or if one of its imports depends on header search paths that are not
+      // consistent with this ImportingInstance.  Try again...
+      continue;
+    } else if (ReadResult == ASTReader::Missing) {
+      diagnoseBuildFailure();
+    }
+    return ReadResult == ASTReader::Success;
+  }
 }
 
 /// \brief Diagnose differences between the current definition of the given
@@ -1012,7 +1133,7 @@ static void checkConfigMacro(Preprocessor &PP, StringRef ConfigMacro,
 static void writeTimestampFile(StringRef TimestampFile) {
   std::string ErrorInfo;
   llvm::raw_fd_ostream Out(TimestampFile.str().c_str(), ErrorInfo,
-                           llvm::sys::fs::F_Binary);
+                           llvm::sys::fs::F_None);
 }
 
 /// \brief Prune the module cache of modules that haven't been accessed in
@@ -1035,7 +1156,7 @@ static void pruneModuleCache(const HeaderSearchOptions &HSOpts) {
   // Check whether the time stamp is older than our pruning interval.
   // If not, do nothing.
   time_t TimeStampModTime = StatBuf.st_mtime;
-  time_t CurrentTime = time(0);
+  time_t CurrentTime = time(nullptr);
   if (CurrentTime - TimeStampModTime <= time_t(HSOpts.ModuleCachePruneInterval))
     return;
 
@@ -1046,7 +1167,7 @@ static void pruneModuleCache(const HeaderSearchOptions &HSOpts) {
 
   // Walk the entire module cache, looking for unused module files and module
   // indices.
-  llvm::error_code EC;
+  std::error_code EC;
   SmallString<128> ModuleCachePathNative;
   llvm::sys::path::native(HSOpts.ModuleCachePath, ModuleCachePathNative);
   for (llvm::sys::fs::directory_iterator
@@ -1057,44 +1178,76 @@ static void pruneModuleCache(const HeaderSearchOptions &HSOpts) {
       continue;
 
     // Walk all of the files within this directory.
-    bool RemovedAllFiles = true;
     for (llvm::sys::fs::directory_iterator File(Dir->path(), EC), FileEnd;
          File != FileEnd && !EC; File.increment(EC)) {
       // We only care about module and global module index files.
-      if (llvm::sys::path::extension(File->path()) != ".pcm" &&
-          llvm::sys::path::filename(File->path()) != "modules.idx") {
-        RemovedAllFiles = false;
+      StringRef Extension = llvm::sys::path::extension(File->path());
+      if (Extension != ".pcm" && Extension != ".timestamp" &&
+          llvm::sys::path::filename(File->path()) != "modules.idx")
         continue;
-      }
 
       // Look at this file. If we can't stat it, there's nothing interesting
       // there.
-      if (::stat(File->path().c_str(), &StatBuf)) {
-        RemovedAllFiles = false;
+      if (::stat(File->path().c_str(), &StatBuf))
         continue;
-      }
 
       // If the file has been used recently enough, leave it there.
       time_t FileAccessTime = StatBuf.st_atime;
       if (CurrentTime - FileAccessTime <=
               time_t(HSOpts.ModuleCachePruneAfter)) {
-        RemovedAllFiles = false;
         continue;
       }
 
       // Remove the file.
-      bool Existed;
-      if (llvm::sys::fs::remove(File->path(), Existed) || !Existed) {
-        RemovedAllFiles = false;
-      }
+      llvm::sys::fs::remove(File->path());
+
+      // Remove the timestamp file.
+      std::string TimpestampFilename = File->path() + ".timestamp";
+      llvm::sys::fs::remove(TimpestampFilename);
     }
 
     // If we removed all of the files in the directory, remove the directory
     // itself.
-    if (RemovedAllFiles) {
-      bool Existed;
-      llvm::sys::fs::remove(Dir->path(), Existed);
+    if (llvm::sys::fs::directory_iterator(Dir->path(), EC) ==
+            llvm::sys::fs::directory_iterator() && !EC)
+      llvm::sys::fs::remove(Dir->path());
+  }
+}
+
+void CompilerInstance::createModuleManager() {
+  if (!ModuleManager) {
+    if (!hasASTContext())
+      createASTContext();
+
+    // If we're not recursively building a module, check whether we
+    // need to prune the module cache.
+    if (getSourceManager().getModuleBuildStack().empty() &&
+        getHeaderSearchOpts().ModuleCachePruneInterval > 0 &&
+        getHeaderSearchOpts().ModuleCachePruneAfter > 0) {
+      pruneModuleCache(getHeaderSearchOpts());
+    }
+
+    HeaderSearchOptions &HSOpts = getHeaderSearchOpts();
+    std::string Sysroot = HSOpts.Sysroot;
+    const PreprocessorOptions &PPOpts = getPreprocessorOpts();
+    ModuleManager = new ASTReader(getPreprocessor(), *Context,
+                                  Sysroot.empty() ? "" : Sysroot.c_str(),
+                                  PPOpts.DisablePCHValidation,
+                                  /*AllowASTWithCompilerErrors=*/false,
+                                  /*AllowConfigurationMismatch=*/false,
+                                  HSOpts.ModulesValidateSystemHeaders,
+                                  getFrontendOpts().UseGlobalModuleIndex);
+    if (hasASTConsumer()) {
+      ModuleManager->setDeserializationListener(
+        getASTConsumer().GetASTDeserializationListener());
+      getASTContext().setASTMutationListener(
+        getASTConsumer().GetASTMutationListener());
     }
+    getASTContext().setExternalSource(ModuleManager);
+    if (hasSema())
+      ModuleManager->InitializeSema(getSema());
+    if (hasASTConsumer())
+      ModuleManager->StartTranslationUnit(&getASTConsumer());
   }
 }
 
@@ -1118,7 +1271,7 @@ CompilerInstance::loadModule(SourceLocation ImportLoc,
     return LastModuleImportResult;
   }
 
-  clang::Module *Module = 0;
+  clang::Module *Module = nullptr;
 
   // If we don't already have information on this module, load the module now.
   llvm::DenseMap<const IdentifierInfo *, clang::Module *>::iterator Known
@@ -1128,51 +1281,34 @@ CompilerInstance::loadModule(SourceLocation ImportLoc,
     Module = Known->second;    
   } else if (ModuleName == getLangOpts().CurrentModule) {
     // This is the module we're building. 
-    Module = PP->getHeaderSearchInfo().getModuleMap().findModule(ModuleName);
+    Module = PP->getHeaderSearchInfo().lookupModule(ModuleName);
     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
   } else {
     // Search for a module with the given name.
     Module = PP->getHeaderSearchInfo().lookupModule(ModuleName);
-    std::string ModuleFileName;
-    if (Module) {
-      ModuleFileName = PP->getHeaderSearchInfo().getModuleFileName(Module);
-    } else
-      ModuleFileName = PP->getHeaderSearchInfo().getModuleFileName(ModuleName);
+    if (!Module) {
+      getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_found)
+      << ModuleName
+      << SourceRange(ImportLoc, ModuleNameLoc);
+      ModuleBuildFailed = true;
+      return ModuleLoadResult();
+    }
+
+    std::string ModuleFileName =
+        PP->getHeaderSearchInfo().getModuleFileName(Module);
 
     // If we don't already have an ASTReader, create one now.
-    if (!ModuleManager) {
-      if (!hasASTContext())
-        createASTContext();
-
-      // If we're not recursively building a module, check whether we
-      // need to prune the module cache.
-      if (getSourceManager().getModuleBuildStack().empty() &&
-          getHeaderSearchOpts().ModuleCachePruneInterval > 0 &&
-          getHeaderSearchOpts().ModuleCachePruneAfter > 0) {
-        pruneModuleCache(getHeaderSearchOpts());
-      }
+    if (!ModuleManager)
+      createModuleManager();
 
-      std::string Sysroot = getHeaderSearchOpts().Sysroot;
-      const PreprocessorOptions &PPOpts = getPreprocessorOpts();
-      ModuleManager = new ASTReader(getPreprocessor(), *Context,
-                                    Sysroot.empty() ? "" : Sysroot.c_str(),
-                                    PPOpts.DisablePCHValidation,
-                                    /*AllowASTWithCompilerErrors=*/false,
-                                    getFrontendOpts().UseGlobalModuleIndex);
-      if (hasASTConsumer()) {
-        ModuleManager->setDeserializationListener(
-          getASTConsumer().GetASTDeserializationListener());
-        getASTContext().setASTMutationListener(
-          getASTConsumer().GetASTMutationListener());
-      }
-      OwningPtr<ExternalASTSource> Source;
-      Source.reset(ModuleManager);
-      getASTContext().setExternalSource(Source);
-      if (hasSema())
-        ModuleManager->InitializeSema(getSema());
-      if (hasASTConsumer())
-        ModuleManager->StartTranslationUnit(&getASTConsumer());
-    }
+    if (TheDependencyFileGenerator)
+      TheDependencyFileGenerator->AttachToASTReader(*ModuleManager);
+
+    if (ModuleDepCollector)
+      ModuleDepCollector->attachToASTReader(*ModuleManager);
+
+    for (auto &Listener : DependencyCollectors)
+      Listener->attachToASTReader(*ModuleManager);
 
     // Try to load the module file.
     unsigned ARRFlags = ASTReader::ARR_OutOfDate | ASTReader::ARR_Missing;
@@ -1184,17 +1320,7 @@ CompilerInstance::loadModule(SourceLocation ImportLoc,
     case ASTReader::OutOfDate:
     case ASTReader::Missing: {
       // The module file is missing or out-of-date. Build it.
-
-      // If we don't have a module, we don't know how to build the module file.
-      // Complain and return.
-      if (!Module) {
-        getDiagnostics().Report(ModuleNameLoc, diag::err_module_not_found)
-          << ModuleName
-          << SourceRange(ImportLoc, ModuleNameLoc);
-        ModuleBuildFailed = true;
-        return ModuleLoadResult();
-      }
-
+      assert(Module && "missing module file");
       // Check whether there is a cycle in the module graph.
       ModuleBuildStack ModPath = getSourceManager().getModuleBuildStack();
       ModuleBuildStack::iterator Pos = ModPath.begin(), PosEnd = ModPath.end();
@@ -1216,6 +1342,9 @@ CompilerInstance::loadModule(SourceLocation ImportLoc,
         return ModuleLoadResult();
       }
 
+      getDiagnostics().Report(ImportLoc, diag::remark_module_build)
+          << ModuleName << ModuleFileName;
+
       // Check whether we have already attempted to build this module (but
       // failed).
       if (getPreprocessorOpts().FailedModules &&
@@ -1227,26 +1356,12 @@ CompilerInstance::loadModule(SourceLocation ImportLoc,
         return ModuleLoadResult();
       }
 
-      // Try to compile the module.
-      compileModule(*this, ModuleNameLoc, Module, ModuleFileName);
-
-      // Try to read the module file, now that we've compiled it.
-      ASTReader::ASTReadResult ReadResult
-        = ModuleManager->ReadAST(ModuleFileName,
-                                 serialization::MK_Module, ImportLoc,
-                                 ASTReader::ARR_Missing);
-      if (ReadResult != ASTReader::Success) {
-        if (ReadResult == ASTReader::Missing) {
-          getDiagnostics().Report(ModuleNameLoc,
-                                  Module? diag::err_module_not_built
-                                        : diag::err_module_not_found)
-            << ModuleName
-            << SourceRange(ImportLoc, ModuleNameLoc);
-        }
-
+      // Try to compile and then load the module.
+      if (!compileAndLoadModule(*this, ImportLoc, ModuleNameLoc, Module,
+                                ModuleFileName)) {
         if (getPreprocessorOpts().FailedModules)
           getPreprocessorOpts().FailedModules->addFailed(ModuleName);
-        KnownModules[Path[0].first] = 0;
+        KnownModules[Path[0].first] = nullptr;
         ModuleBuildFailed = true;
         return ModuleLoadResult();
       }
@@ -1261,23 +1376,16 @@ CompilerInstance::loadModule(SourceLocation ImportLoc,
       ModuleLoader::HadFatalFailure = true;
       // FIXME: The ASTReader will already have complained, but can we showhorn
       // that diagnostic information into a more useful form?
-      KnownModules[Path[0].first] = 0;
+      KnownModules[Path[0].first] = nullptr;
       return ModuleLoadResult();
 
     case ASTReader::Failure:
       ModuleLoader::HadFatalFailure = true;
       // Already complained, but note now that we failed.
-      KnownModules[Path[0].first] = 0;
+      KnownModules[Path[0].first] = nullptr;
       ModuleBuildFailed = true;
       return ModuleLoadResult();
     }
-    
-    if (!Module) {
-      // If we loaded the module directly, without finding a module map first,
-      // we'll have loaded the module's information from the module itself.
-      Module = PP->getHeaderSearchInfo().getModuleMap()
-                 .findModule((Path[0].first->getName()));
-    }
 
     // Cache the result of this top-level module lookup for later.
     Known = KnownModules.insert(std::make_pair(Path[0].first, Module)).first;
@@ -1354,17 +1462,25 @@ CompilerInstance::loadModule(SourceLocation ImportLoc,
       getDiagnostics().Report(ImportLoc, diag::warn_missing_submodule)
         << Module->getFullModuleName()
         << SourceRange(Path.front().second, Path.back().second);
-      
-      return ModuleLoadResult(0, true);
+
+      return ModuleLoadResult(nullptr, true);
     }
 
     // Check whether this module is available.
     clang::Module::Requirement Requirement;
-    if (!Module->isAvailable(getLangOpts(), getTarget(), Requirement)) {
-      getDiagnostics().Report(ImportLoc, diag::err_module_unavailable)
-        << Module->getFullModuleName()
-        << Requirement.second << Requirement.first
-        << SourceRange(Path.front().second, Path.back().second);
+    clang::Module::HeaderDirective MissingHeader;
+    if (!Module->isAvailable(getLangOpts(), getTarget(), Requirement,
+                             MissingHeader)) {
+      if (MissingHeader.FileNameLoc.isValid()) {
+        getDiagnostics().Report(MissingHeader.FileNameLoc,
+                                diag::err_module_header_missing)
+          << MissingHeader.IsUmbrella << MissingHeader.FileName;
+      } else {
+        getDiagnostics().Report(ImportLoc, diag::err_module_unavailable)
+          << Module->getFullModuleName()
+          << Requirement.second << Requirement.first
+          << SourceRange(Path.front().second, Path.back().second);
+      }
       LastModuleImportLoc = ImportLoc;
       LastModuleImportResult = ModuleLoadResult();
       return ModuleLoadResult();
@@ -1405,3 +1521,84 @@ void CompilerInstance::makeModuleVisible(Module *Mod,
   ModuleManager->makeModuleVisible(Mod, Visibility, ImportLoc, Complain);
 }
 
+GlobalModuleIndex *CompilerInstance::loadGlobalModuleIndex(
+    SourceLocation TriggerLoc) {
+  if (!ModuleManager)
+    createModuleManager();
+  // Can't do anything if we don't have the module manager.
+  if (!ModuleManager)
+    return nullptr;
+  // Get an existing global index.  This loads it if not already
+  // loaded.
+  ModuleManager->loadGlobalIndex();
+  GlobalModuleIndex *GlobalIndex = ModuleManager->getGlobalIndex();
+  // If the global index doesn't exist, create it.
+  if (!GlobalIndex && shouldBuildGlobalModuleIndex() && hasFileManager() &&
+      hasPreprocessor()) {
+    llvm::sys::fs::create_directories(
+      getPreprocessor().getHeaderSearchInfo().getModuleCachePath());
+    GlobalModuleIndex::writeIndex(
+      getFileManager(),
+      getPreprocessor().getHeaderSearchInfo().getModuleCachePath());
+    ModuleManager->resetForReload();
+    ModuleManager->loadGlobalIndex();
+    GlobalIndex = ModuleManager->getGlobalIndex();
+  }
+  // For finding modules needing to be imported for fixit messages,
+  // we need to make the global index cover all modules, so we do that here.
+  if (!HaveFullGlobalModuleIndex && GlobalIndex && !buildingModule()) {
+    ModuleMap &MMap = getPreprocessor().getHeaderSearchInfo().getModuleMap();
+    bool RecreateIndex = false;
+    for (ModuleMap::module_iterator I = MMap.module_begin(),
+        E = MMap.module_end(); I != E; ++I) {
+      Module *TheModule = I->second;
+      const FileEntry *Entry = TheModule->getASTFile();
+      if (!Entry) {
+        SmallVector<std::pair<IdentifierInfo *, SourceLocation>, 2> Path;
+        Path.push_back(std::make_pair(
+				  getPreprocessor().getIdentifierInfo(TheModule->Name), TriggerLoc));
+        std::reverse(Path.begin(), Path.end());
+		    // Load a module as hidden.  This also adds it to the global index.
+        loadModule(TheModule->DefinitionLoc, Path,
+                                             Module::Hidden, false);
+        RecreateIndex = true;
+      }
+    }
+    if (RecreateIndex) {
+      GlobalModuleIndex::writeIndex(
+        getFileManager(),
+        getPreprocessor().getHeaderSearchInfo().getModuleCachePath());
+      ModuleManager->resetForReload();
+      ModuleManager->loadGlobalIndex();
+      GlobalIndex = ModuleManager->getGlobalIndex();
+    }
+    HaveFullGlobalModuleIndex = true;
+  }
+  return GlobalIndex;
+}
+
+// Check global module index for missing imports.
+bool
+CompilerInstance::lookupMissingImports(StringRef Name,
+                                       SourceLocation TriggerLoc) {
+  // Look for the symbol in non-imported modules, but only if an error
+  // actually occurred.
+  if (!buildingModule()) {
+    // Load global module index, or retrieve a previously loaded one.
+    GlobalModuleIndex *GlobalIndex = loadGlobalModuleIndex(
+      TriggerLoc);
+
+    // Only if we have a global index.
+    if (GlobalIndex) {
+      GlobalModuleIndex::HitSet FoundModules;
+
+      // Find the modules that reference the identifier.
+      // Note that this only finds top-level modules.
+      // We'll let diagnoseTypo find the actual declaration module.
+      if (GlobalIndex->lookupIdentifier(Name, FoundModules))
+        return true;
+    }
+  }
+
+  return false;
+}
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 8db5cf1bc21a..ce61a4653d2e 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -8,19 +8,19 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Frontend/CompilerInvocation.h"
-#include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/Version.h"
 #include "clang/Driver/DriverDiagnostic.h"
 #include "clang/Driver/Options.h"
 #include "clang/Driver/Util.h"
+#include "clang/Frontend/FrontendDiagnostic.h"
 #include "clang/Frontend/LangStandard.h"
 #include "clang/Frontend/Utils.h"
 #include "clang/Lex/HeaderSearchOptions.h"
 #include "clang/Serialization/ASTReader.h"
 #include "llvm/ADT/Hashing.h"
-#include "llvm/ADT/OwningPtr.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/Triple.h"
@@ -28,13 +28,16 @@
 #include "llvm/Option/ArgList.h"
 #include "llvm/Option/OptTable.h"
 #include "llvm/Option/Option.h"
+#include "llvm/Support/CodeGen.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/Process.h"
-#include "llvm/Support/system_error.h"
+#include <atomic>
+#include <memory>
 #include <sys/stat.h>
+#include <system_error>
 using namespace clang;
 
 //===----------------------------------------------------------------------===//
@@ -55,6 +58,8 @@ CompilerInvocationBase::CompilerInvocationBase(const CompilerInvocationBase &X)
     HeaderSearchOpts(new HeaderSearchOptions(X.getHeaderSearchOpts())),
     PreprocessorOpts(new PreprocessorOptions(X.getPreprocessorOpts())) {}
 
+CompilerInvocationBase::~CompilerInvocationBase() {}
+
 //===----------------------------------------------------------------------===//
 // Deserialization (from args)
 //===----------------------------------------------------------------------===//
@@ -106,25 +111,21 @@ static unsigned getOptimizationLevelSize(ArgList &Args) {
   return 0;
 }
 
-static void addWarningArgs(ArgList &Args, std::vector<std::string> &Warnings) {
-  for (arg_iterator I = Args.filtered_begin(OPT_W_Group),
-         E = Args.filtered_end(); I != E; ++I) {
-    Arg *A = *I;
-    // If the argument is a pure flag, add its name (minus the "W" at the beginning)
-    // to the warning list. Else, add its value (for the OPT_W case).
+static void addDiagnosticArgs(ArgList &Args, OptSpecifier Group,
+                              OptSpecifier GroupWithValue,
+                              std::vector<std::string> &Diagnostics) {
+  for (Arg *A : Args.filtered(Group)) {
     if (A->getOption().getKind() == Option::FlagClass) {
-      Warnings.push_back(A->getOption().getName().substr(1));
+      // The argument is a pure flag (such as OPT_Wall or OPT_Wdeprecated). Add
+      // its name (minus the "W" or "R" at the beginning) to the warning list.
+      Diagnostics.push_back(A->getOption().getName().drop_front(1));
+    } else if (A->getOption().matches(GroupWithValue)) {
+      // This is -Wfoo= or -Rfoo=, where foo is the name of the diagnostic group.
+      Diagnostics.push_back(A->getOption().getName().drop_front(1).rtrim("=-"));
     } else {
-      for (unsigned Idx = 0, End = A->getNumValues();
-           Idx < End; ++Idx) {
-        StringRef V = A->getValue(Idx);
-        // "-Wl," and such are not warning options.
-        // FIXME: Should be handled by putting these in separate flags.
-        if (V.startswith("l,") || V.startswith("a,") || V.startswith("p,"))
-          continue;
-
-        Warnings.push_back(V);
-      }
+      // Otherwise, add its value (for OPT_W_Joined and similar).
+      for (const char *Arg : A->getValues())
+        Diagnostics.push_back(Arg);
     }
   }
 }
@@ -262,7 +263,7 @@ static bool ParseAnalyzerArgs(AnalyzerOptions &Opts, ArgList &Args,
     configList.split(configVals, ",");
     for (unsigned i = 0, e = configVals.size(); i != e; ++i) {
       StringRef key, val;
-      llvm::tie(key, val) = configVals[i].split("=");
+      std::tie(key, val) = configVals[i].split("=");
       if (val.empty()) {
         Diags.Report(SourceLocation(),
                      diag::err_analyzer_config_no_value) << configVals[i];
@@ -294,8 +295,36 @@ static void ParseCommentArgs(CommentOptions &Opts, ArgList &Args) {
   Opts.ParseAllComments = Args.hasArg(OPT_fparse_all_comments);
 }
 
+static StringRef getCodeModel(ArgList &Args, DiagnosticsEngine &Diags) {
+  if (Arg *A = Args.getLastArg(OPT_mcode_model)) {
+    StringRef Value = A->getValue();
+    if (Value == "small" || Value == "kernel" || Value == "medium" ||
+        Value == "large")
+      return Value;
+    Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) << Value;
+  }
+  return "default";
+}
+
+/// \brief Create a new Regex instance out of the string value in \p RpassArg.
+/// It returns a pointer to the newly generated Regex instance.
+static std::shared_ptr<llvm::Regex>
+GenerateOptimizationRemarkRegex(DiagnosticsEngine &Diags, ArgList &Args,
+                                Arg *RpassArg) {
+  StringRef Val = RpassArg->getValue();
+  std::string RegexError;
+  std::shared_ptr<llvm::Regex> Pattern = std::make_shared<llvm::Regex>(Val);
+  if (!Pattern->isValid(RegexError)) {
+    Diags.Report(diag::err_drv_optimization_remark_pattern)
+        << RegexError << RpassArg->getAsString(Args);
+    Pattern.reset();
+  }
+  return Pattern;
+}
+
 static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
-                             DiagnosticsEngine &Diags) {
+                             DiagnosticsEngine &Diags,
+                             const TargetOptions &TargetOpts) {
   using namespace options;
   bool Success = true;
 
@@ -322,10 +351,17 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
     Opts.setDebugInfo(CodeGenOptions::DebugLineTablesOnly);
   } else if (Args.hasArg(OPT_g_Flag) || Args.hasArg(OPT_gdwarf_2) ||
              Args.hasArg(OPT_gdwarf_3) || Args.hasArg(OPT_gdwarf_4)) {
-    if (Args.hasFlag(OPT_flimit_debug_info, OPT_fno_limit_debug_info, true))
-      Opts.setDebugInfo(CodeGenOptions::LimitedDebugInfo);
-    else
+    bool Default = false;
+    // Until dtrace (via CTF) and LLDB can deal with distributed debug info,
+    // Darwin and FreeBSD default to standalone/full debug info.
+    if (llvm::Triple(TargetOpts.Triple).isOSDarwin() ||
+        llvm::Triple(TargetOpts.Triple).isOSFreeBSD())
+      Default = true;
+
+    if (Args.hasFlag(OPT_fstandalone_debug, OPT_fno_standalone_debug, Default))
       Opts.setDebugInfo(CodeGenOptions::FullDebugInfo);
+    else
+      Opts.setDebugInfo(CodeGenOptions::LimitedDebugInfo);
   }
   Opts.DebugColumnInfo = Args.hasArg(OPT_dwarf_column_info);
   Opts.SplitDwarfFile = Args.getLastArgValue(OPT_split_dwarf_file);
@@ -358,20 +394,22 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
                    (Opts.OptimizationLevel > 1 && !Opts.OptimizeSize));
   Opts.RerollLoops = Args.hasArg(OPT_freroll_loops);
 
+  Opts.DisableIntegratedAS = Args.hasArg(OPT_fno_integrated_as);
   Opts.Autolink = !Args.hasArg(OPT_fno_autolink);
   Opts.SampleProfileFile = Args.getLastArgValue(OPT_fprofile_sample_use_EQ);
+  Opts.ProfileInstrGenerate = Args.hasArg(OPT_fprofile_instr_generate);
+  Opts.InstrProfileInput = Args.getLastArgValue(OPT_fprofile_instr_use_EQ);
   Opts.AsmVerbose = Args.hasArg(OPT_masm_verbose);
   Opts.ObjCAutoRefCountExceptions = Args.hasArg(OPT_fobjc_arc_exceptions);
   Opts.CUDAIsDevice = Args.hasArg(OPT_fcuda_is_device);
   Opts.CXAAtExit = !Args.hasArg(OPT_fno_use_cxa_atexit);
   Opts.CXXCtorDtorAliases = Args.hasArg(OPT_mconstructor_aliases);
-  Opts.CodeModel = Args.getLastArgValue(OPT_mcode_model);
+  Opts.CodeModel = getCodeModel(Args, Diags);
   Opts.DebugPass = Args.getLastArgValue(OPT_mdebug_pass);
   Opts.DisableFPElim = Args.hasArg(OPT_mdisable_fp_elim);
   Opts.DisableFree = Args.hasArg(OPT_disable_free);
   Opts.DisableTailCalls = Args.hasArg(OPT_mdisable_tail_calls);
   Opts.FloatABI = Args.getLastArgValue(OPT_mfloat_abi);
-  Opts.HiddenWeakVTables = Args.hasArg(OPT_fhidden_weak_vtables);
   Opts.LessPreciseFPMAD = Args.hasArg(OPT_cl_mad_enable);
   Opts.LimitFloatPrecision = Args.getLastArgValue(OPT_mlimit_float_precision);
   Opts.NoInfsFPMath = (Args.hasArg(OPT_menable_no_infinities) ||
@@ -389,7 +427,6 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.RelaxAll = Args.hasArg(OPT_mrelax_all);
   Opts.OmitLeafFramePointer = Args.hasArg(OPT_momit_leaf_frame_pointer);
   Opts.SaveTempLabels = Args.hasArg(OPT_msave_temp_labels);
-  Opts.NoDwarf2CFIAsm = Args.hasArg(OPT_fno_dwarf2_cfi_asm);
   Opts.NoDwarfDirectoryAsm = Args.hasArg(OPT_fno_dwarf_directory_asm);
   Opts.SoftFloat = Args.hasArg(OPT_msoft_float);
   Opts.StrictEnums = Args.hasArg(OPT_fstrict_enums);
@@ -437,15 +474,14 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.InstrumentFunctions = Args.hasArg(OPT_finstrument_functions);
   Opts.InstrumentForProfiling = Args.hasArg(OPT_pg);
   Opts.EmitOpenCLArgMetadata = Args.hasArg(OPT_cl_kernel_arg_info);
+  Opts.CompressDebugSections = Args.hasArg(OPT_compress_debug_sections);
   Opts.DebugCompilationDir = Args.getLastArgValue(OPT_fdebug_compilation_dir);
   Opts.LinkBitcodeFile = Args.getLastArgValue(OPT_mlink_bitcode_file);
   Opts.SanitizerBlacklistFile = Args.getLastArgValue(OPT_fsanitize_blacklist);
   Opts.SanitizeMemoryTrackOrigins =
-    Args.hasArg(OPT_fsanitize_memory_track_origins);
-  Opts.SanitizeAddressZeroBaseShadow =
-    Args.hasArg(OPT_fsanitize_address_zero_base_shadow);
+      getLastArgIntValue(Args, OPT_fsanitize_memory_track_origins_EQ, 0, Diags);
   Opts.SanitizeUndefinedTrapOnError =
-    Args.hasArg(OPT_fsanitize_undefined_trap_on_error);
+      Args.hasArg(OPT_fsanitize_undefined_trap_on_error);
   Opts.SSPBufferSize =
       getLastArgIntValue(Args, OPT_stack_protector_buffer_size, 8, Diags);
   Opts.StackRealignment = Args.hasArg(OPT_mstackrealign);
@@ -510,6 +546,30 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   }
 
   Opts.DependentLibraries = Args.getAllArgValues(OPT_dependent_lib);
+  bool NeedLocTracking = false;
+
+  if (Arg *A = Args.getLastArg(OPT_Rpass_EQ)) {
+    Opts.OptimizationRemarkPattern =
+        GenerateOptimizationRemarkRegex(Diags, Args, A);
+    NeedLocTracking = true;
+  }
+
+  if (Arg *A = Args.getLastArg(OPT_Rpass_missed_EQ)) {
+    Opts.OptimizationRemarkMissedPattern =
+        GenerateOptimizationRemarkRegex(Diags, Args, A);
+    NeedLocTracking = true;
+  }
+
+  if (Arg *A = Args.getLastArg(OPT_Rpass_analysis_EQ)) {
+    Opts.OptimizationRemarkAnalysisPattern =
+        GenerateOptimizationRemarkRegex(Diags, Args, A);
+    NeedLocTracking = true;
+  }
+
+  // If the user requested one of the flags in the -Rpass family, make sure
+  // that the backend tracks source location information.
+  if (NeedLocTracking && Opts.getDebugInfo() == CodeGenOptions::NoDebugInfo)
+    Opts.setDebugInfo(CodeGenOptions::LocTrackingOnly);
 
   return Success;
 }
@@ -520,12 +580,15 @@ static void ParseDependencyOutputArgs(DependencyOutputOptions &Opts,
   Opts.OutputFile = Args.getLastArgValue(OPT_dependency_file);
   Opts.Targets = Args.getAllArgValues(OPT_MT);
   Opts.IncludeSystemHeaders = Args.hasArg(OPT_sys_header_deps);
+  Opts.IncludeModuleFiles = Args.hasArg(OPT_module_file_deps);
   Opts.UsePhonyTargets = Args.hasArg(OPT_MP);
   Opts.ShowHeaderIncludes = Args.hasArg(OPT_H);
   Opts.HeaderIncludeOutputFile = Args.getLastArgValue(OPT_header_include_file);
   Opts.AddMissingHeaderDeps = Args.hasArg(OPT_MG);
   Opts.PrintShowIncludes = Args.hasArg(OPT_show_includes);
   Opts.DOTOutputFile = Args.getLastArgValue(OPT_dependency_dot);
+  Opts.ModuleDependencyOutputDir =
+      Args.getLastArgValue(OPT_module_dependency_dir);
 }
 
 bool clang::ParseDiagnosticArgs(DiagnosticOptions &Opts, ArgList &Args,
@@ -632,7 +695,8 @@ bool clang::ParseDiagnosticArgs(DiagnosticOptions &Opts, ArgList &Args,
       << Opts.TabStop << DiagnosticOptions::DefaultTabStop;
   }
   Opts.MessageLength = getLastArgIntValue(Args, OPT_fmessage_length, 0, Diags);
-  addWarningArgs(Args, Opts.Warnings);
+  addDiagnosticArgs(Args, OPT_W_Group, OPT_W_value_Group, Opts.Warnings);
+  addDiagnosticArgs(Args, OPT_R_Group, OPT_R_value_Group, Opts.Remarks);
 
   return Success;
 }
@@ -692,6 +756,8 @@ static InputKind ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
       Opts.ProgramAction = frontend::ParseSyntaxOnly; break;
     case OPT_module_file_info:
       Opts.ProgramAction = frontend::ModuleFileInfo; break;
+    case OPT_verify_pch:
+      Opts.ProgramAction = frontend::VerifyPCH; break;
     case OPT_print_decl_contexts:
       Opts.ProgramAction = frontend::PrintDeclContext; break;
     case OPT_print_preamble:
@@ -820,10 +886,12 @@ static InputKind ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
     Opts.ObjCMTAction |= FrontendOptions::ObjCMT_AtomicProperty;
   if (Args.hasArg(OPT_objcmt_ns_nonatomic_iosonly))
     Opts.ObjCMTAction |= FrontendOptions::ObjCMT_NsAtomicIOSOnlyProperty;
+  if (Args.hasArg(OPT_objcmt_migrate_designated_init))
+    Opts.ObjCMTAction |= FrontendOptions::ObjCMT_DesignatedInitializer;
   if (Args.hasArg(OPT_objcmt_migrate_all))
     Opts.ObjCMTAction |= FrontendOptions::ObjCMT_MigrateDecls;
 
-  Opts.ObjCMTWhiteListPath = Args.getLastArgValue(OPT_objcmt_white_list_dir_path);
+  Opts.ObjCMTWhiteListPath = Args.getLastArgValue(OPT_objcmt_whitelist_dir_path);
 
   if (Opts.ARCMTAction != FrontendOptions::ARCMT_None &&
       Opts.ObjCMTAction != FrontendOptions::ObjCMT_None) {
@@ -906,6 +974,7 @@ static void ParseHeaderSearchArgs(HeaderSearchOptions &Opts, ArgList &Args) {
     Opts.UseLibcxx = (strcmp(A->getValue(), "libc++") == 0);
   Opts.ResourceDir = Args.getLastArgValue(OPT_resource_dir);
   Opts.ModuleCachePath = Args.getLastArgValue(OPT_fmodules_cache_path);
+  Opts.ModuleUserBuildPath = Args.getLastArgValue(OPT_fmodules_user_build_path);
   Opts.DisableModuleHash = Args.hasArg(OPT_fdisable_module_hash);
   // -fmodules implies -fmodule-maps
   Opts.ModuleMaps = Args.hasArg(OPT_fmodule_maps) || Args.hasArg(OPT_fmodules);
@@ -913,6 +982,13 @@ static void ParseHeaderSearchArgs(HeaderSearchOptions &Opts, ArgList &Args) {
       getLastArgIntValue(Args, OPT_fmodules_prune_interval, 7 * 24 * 60 * 60);
   Opts.ModuleCachePruneAfter =
       getLastArgIntValue(Args, OPT_fmodules_prune_after, 31 * 24 * 60 * 60);
+  Opts.ModulesValidateOncePerBuildSession =
+      Args.hasArg(OPT_fmodules_validate_once_per_build_session);
+  Opts.BuildSessionTimestamp =
+      getLastArgUInt64Value(Args, OPT_fbuild_session_timestamp, 0);
+  Opts.ModulesValidateSystemHeaders =
+      Args.hasArg(OPT_fmodules_validate_system_headers);
+
   for (arg_iterator it = Args.filtered_begin(OPT_fmodules_ignore_macro),
                     ie = Args.filtered_end();
        it != ie; ++it) {
@@ -998,12 +1074,16 @@ static void ParseHeaderSearchArgs(HeaderSearchOptions &Opts, ArgList &Args) {
   }
 
   // Add the path prefixes which are implicitly treated as being system headers.
-  for (arg_iterator I = Args.filtered_begin(OPT_isystem_prefix,
-                                            OPT_ino_system_prefix),
+  for (arg_iterator I = Args.filtered_begin(OPT_system_header_prefix,
+                                            OPT_no_system_header_prefix),
                     E = Args.filtered_end();
        I != E; ++I)
-    Opts.AddSystemHeaderPrefix((*I)->getValue(),
-                               (*I)->getOption().matches(OPT_isystem_prefix));
+    Opts.AddSystemHeaderPrefix(
+        (*I)->getValue(), (*I)->getOption().matches(OPT_system_header_prefix));
+
+  for (arg_iterator I = Args.filtered_begin(OPT_ivfsoverlay),
+       E = Args.filtered_end(); I != E; ++I)
+    Opts.AddVFSOverlayFile((*I)->getValue());
 }
 
 void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK,
@@ -1056,6 +1136,7 @@ void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK,
   Opts.CPlusPlus = Std.isCPlusPlus();
   Opts.CPlusPlus11 = Std.isCPlusPlus11();
   Opts.CPlusPlus1y = Std.isCPlusPlus1y();
+  Opts.CPlusPlus1z = Std.isCPlusPlus1z();
   Opts.Digraphs = Std.hasDigraphs();
   Opts.GNUMode = Std.isGNUMode();
   Opts.GNUInline = !Std.isC99();
@@ -1063,18 +1144,13 @@ void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK,
   Opts.ImplicitInt = Std.hasImplicitInt();
 
   // Set OpenCL Version.
-  if (LangStd == LangStandard::lang_opencl) {
-    Opts.OpenCL = 1;
+  Opts.OpenCL = LangStd == LangStandard::lang_opencl || IK == IK_OpenCL;
+  if (LangStd == LangStandard::lang_opencl)
     Opts.OpenCLVersion = 100;
-  }
-  else if (LangStd == LangStandard::lang_opencl11) {
-      Opts.OpenCL = 1;
+  else if (LangStd == LangStandard::lang_opencl11)
       Opts.OpenCLVersion = 110;
-  }
-  else if (LangStd == LangStandard::lang_opencl12) {
-    Opts.OpenCL = 1;
+  else if (LangStd == LangStandard::lang_opencl12)
     Opts.OpenCLVersion = 120;
-  }
   
   // OpenCL has some additional defaults.
   if (Opts.OpenCL) {
@@ -1085,12 +1161,14 @@ void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK,
     Opts.NativeHalfType = 1;
   }
 
-  if (LangStd == LangStandard::lang_cuda)
-    Opts.CUDA = 1;
+  Opts.CUDA = LangStd == LangStandard::lang_cuda || IK == IK_CUDA;
 
   // OpenCL and C++ both have bool, true, false keywords.
   Opts.Bool = Opts.OpenCL || Opts.CPlusPlus;
 
+  // OpenCL has half keyword
+  Opts.Half = Opts.OpenCL;
+
   // C++ has wchar_t keyword.
   Opts.WChar = Opts.CPlusPlus;
 
@@ -1099,7 +1177,8 @@ void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK,
 
   // Mimicing gcc's behavior, trigraphs are only enabled if -trigraphs
   // is specified, or -std is set to a conforming mode.
-  Opts.Trigraphs = !Opts.GNUMode;
+  // Trigraphs are disabled by default in c++1z onwards.
+  Opts.Trigraphs = !Opts.GNUMode && !Opts.CPlusPlus1z;
 
   Opts.DollarIdents = !Opts.AsmPreprocessor;
 
@@ -1125,6 +1204,43 @@ static Visibility parseVisibility(Arg *arg, ArgList &args,
   return DefaultVisibility;
 }
 
+static unsigned parseMSCVersion(ArgList &Args, DiagnosticsEngine &Diags) {
+  auto Arg = Args.getLastArg(OPT_fms_compatibility_version);
+  if (!Arg)
+    return 0;
+
+  // The MSC versioning scheme involves four versioning components:
+  //  - Major
+  //  - Minor
+  //  - Build
+  //  - Patch
+  //
+  // We accept either the old style (_MSC_VER) value, or a _MSC_FULL_VER value.
+  // Additionally, the value may be provided in the form of a more readable
+  // MM.mm.bbbbb.pp version.
+  //
+  // Unfortunately, due to the bit-width limitations, we cannot currently encode
+  // the value for the patch level.
+
+  unsigned VC[4] = {0};
+  StringRef Value = Arg->getValue();
+  SmallVector<StringRef, 4> Components;
+
+  Value.split(Components, ".", llvm::array_lengthof(VC));
+  for (unsigned CI = 0,
+                CE = std::min(Components.size(), llvm::array_lengthof(VC));
+       CI < CE; ++CI) {
+    if (Components[CI].getAsInteger(10, VC[CI])) {
+      Diags.Report(diag::err_drv_invalid_value)
+        << Arg->getAsString(Args) << Value;
+      return 0;
+    }
+  }
+
+  // FIXME we cannot encode the patch level
+  return VC[0] * 10000000 + VC[1] * 100000 + VC[2];
+}
+
 static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
                           DiagnosticsEngine &Diags) {
   // FIXME: Cleanup per-file based stuff.
@@ -1139,7 +1255,8 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
       Diags.Report(diag::err_drv_invalid_value)
         << A->getAsString(Args) << A->getValue();
     else {
-      // Valid standard, check to make sure language and standard are compatable.    
+      // Valid standard, check to make sure language and standard are
+      // compatible.
       const LangStandard &Std = LangStandard::getLangStandardForKind(LangStd);
       switch (IK) {
       case IK_C:
@@ -1290,11 +1407,11 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
                                    OPT_fno_dollars_in_identifiers,
                                    Opts.DollarIdents);
   Opts.PascalStrings = Args.hasArg(OPT_fpascal_strings);
-  Opts.MicrosoftExt
-    = Args.hasArg(OPT_fms_extensions) || Args.hasArg(OPT_fms_compatibility);
-  Opts.MicrosoftMode = Args.hasArg(OPT_fms_compatibility);
+  Opts.MSVCCompat = Args.hasArg(OPT_fms_compatibility);
+  Opts.MicrosoftExt = Opts.MSVCCompat || Args.hasArg(OPT_fms_extensions);
   Opts.AsmBlocks = Args.hasArg(OPT_fasm_blocks) || Opts.MicrosoftExt;
-  Opts.MSCVersion = getLastArgIntValue(Args, OPT_fmsc_version, 0, Diags);
+  Opts.MSCompatibilityVersion = parseMSCVersion(Args, Diags);
+  Opts.VtorDispMode = getLastArgIntValue(Args, OPT_vtordisp_mode_EQ, 1, Diags);
   Opts.Borland = Args.hasArg(OPT_fborland_extensions);
   Opts.WritableStrings = Args.hasArg(OPT_fwritable_strings);
   Opts.ConstStrings = Args.hasFlag(OPT_fconst_strings, OPT_fno_const_strings,
@@ -1310,13 +1427,20 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
   Opts.TraditionalCPP = Args.hasArg(OPT_traditional_cpp);
 
   Opts.RTTI = !Args.hasArg(OPT_fno_rtti);
+  Opts.RTTIData = Opts.RTTI && !Args.hasArg(OPT_fno_rtti_data);
   Opts.Blocks = Args.hasArg(OPT_fblocks);
   Opts.BlocksRuntimeOptional = Args.hasArg(OPT_fblocks_runtime_optional);
   Opts.Modules = Args.hasArg(OPT_fmodules);
-  Opts.ModulesDeclUse = Args.hasArg(OPT_fmodules_decluse);
+  Opts.ModulesStrictDeclUse = Args.hasArg(OPT_fmodules_strict_decluse);
+  Opts.ModulesDeclUse =
+      Args.hasArg(OPT_fmodules_decluse) || Opts.ModulesStrictDeclUse;
+  Opts.ModulesSearchAll = Opts.Modules &&
+    !Args.hasArg(OPT_fno_modules_search_all) &&
+    Args.hasArg(OPT_fmodules_search_all);
+  Opts.ModulesErrorRecovery = !Args.hasArg(OPT_fno_modules_error_recovery);
   Opts.CharIsSigned = Opts.OpenCL || !Args.hasArg(OPT_fno_signed_char);
   Opts.WChar = Opts.CPlusPlus && !Args.hasArg(OPT_fno_wchar);
-  Opts.ShortWChar = Args.hasArg(OPT_fshort_wchar);
+  Opts.ShortWChar = Args.hasFlag(OPT_fshort_wchar, OPT_fno_short_wchar, false);
   Opts.ShortEnums = Args.hasArg(OPT_fshort_enums);
   Opts.Freestanding = Args.hasArg(OPT_ffreestanding);
   Opts.NoBuiltin = Args.hasArg(OPT_fno_builtin) || Opts.Freestanding;
@@ -1391,8 +1515,30 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
     }
   }
 
-  // Check if -fopenmp is specified.
-  Opts.OpenMP = Args.hasArg(OPT_fopenmp);
+  if (Arg *A = Args.getLastArg(OPT_fms_memptr_rep_EQ)) {
+    LangOptions::PragmaMSPointersToMembersKind InheritanceModel =
+        llvm::StringSwitch<LangOptions::PragmaMSPointersToMembersKind>(
+            A->getValue())
+            .Case("single",
+                  LangOptions::PPTMK_FullGeneralitySingleInheritance)
+            .Case("multiple",
+                  LangOptions::PPTMK_FullGeneralityMultipleInheritance)
+            .Case("virtual",
+                  LangOptions::PPTMK_FullGeneralityVirtualInheritance)
+            .Default(LangOptions::PPTMK_BestCase);
+    if (InheritanceModel == LangOptions::PPTMK_BestCase)
+      Diags.Report(diag::err_drv_invalid_value)
+          << "-fms-memptr-rep=" << A->getValue();
+
+    Opts.setMSPointerToMemberRepresentationMethod(InheritanceModel);
+  }
+
+  // Check if -fopenmp= is specified.
+  if (const Arg *A = Args.getLastArg(options::OPT_fopenmp_EQ)) {
+    Opts.OpenMP = llvm::StringSwitch<bool>(A->getValue())
+        .Case("libiomp5", true)
+        .Default(false);
+  }
 
   // Record whether the __DEPRECATED define was requested.
   Opts.Deprecated = Args.hasFlag(OPT_fdeprecated_macro,
@@ -1424,7 +1570,8 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
     break;
   case 0: Opts.setStackProtector(LangOptions::SSPOff); break;
   case 1: Opts.setStackProtector(LangOptions::SSPOn);  break;
-  case 2: Opts.setStackProtector(LangOptions::SSPReq); break;
+  case 2: Opts.setStackProtector(LangOptions::SSPStrong); break;
+  case 3: Opts.setStackProtector(LangOptions::SSPReq); break;
   }
 
   // Parse -fsanitize= arguments.
@@ -1575,6 +1722,7 @@ static void ParsePreprocessorOutputArgs(PreprocessorOutputOptions &Opts,
   case frontend::GeneratePTH:
   case frontend::ParseSyntaxOnly:
   case frontend::ModuleFileInfo:
+  case frontend::VerifyPCH:
   case frontend::PluginAction:
   case frontend::PrintDeclContext:
   case frontend::RewriteObjC:
@@ -1605,7 +1753,6 @@ static void ParsePreprocessorOutputArgs(PreprocessorOutputOptions &Opts,
 static void ParseTargetArgs(TargetOptions &Opts, ArgList &Args) {
   using namespace options;
   Opts.ABI = Args.getLastArgValue(OPT_target_abi);
-  Opts.CXXABI = Args.getLastArgValue(OPT_cxx_abi);
   Opts.CPU = Args.getLastArgValue(OPT_target_cpu);
   Opts.FPMath = Args.getLastArgValue(OPT_mfpmath);
   Opts.FeaturesAsWritten = Args.getAllArgValues(OPT_target_feature);
@@ -1617,8 +1764,6 @@ static void ParseTargetArgs(TargetOptions &Opts, ArgList &Args) {
     Opts.Triple = llvm::sys::getDefaultTargetTriple();
 }
 
-//
-
 bool CompilerInvocation::CreateFromArgs(CompilerInvocation &Res,
                                         const char *const *ArgBegin,
                                         const char *const *ArgEnd,
@@ -1626,12 +1771,12 @@ bool CompilerInvocation::CreateFromArgs(CompilerInvocation &Res,
   bool Success = true;
 
   // Parse the arguments.
-  OwningPtr<OptTable> Opts(createDriverOptTable());
+  std::unique_ptr<OptTable> Opts(createDriverOptTable());
   const unsigned IncludedFlagsBitmask = options::CC1Option;
   unsigned MissingArgIndex, MissingArgCount;
-  OwningPtr<InputArgList> Args(
-    Opts->ParseArgs(ArgBegin, ArgEnd, MissingArgIndex, MissingArgCount,
-                    IncludedFlagsBitmask));
+  std::unique_ptr<InputArgList> Args(
+      Opts->ParseArgs(ArgBegin, ArgEnd, MissingArgIndex, MissingArgCount,
+                      IncludedFlagsBitmask));
 
   // Check for missing argument error.
   if (MissingArgCount) {
@@ -1656,8 +1801,9 @@ bool CompilerInvocation::CreateFromArgs(CompilerInvocation &Res,
   ParseFileSystemArgs(Res.getFileSystemOpts(), *Args);
   // FIXME: We shouldn't have to pass the DashX option around here
   InputKind DashX = ParseFrontendArgs(Res.getFrontendOpts(), *Args, Diags);
-  Success = ParseCodeGenArgs(Res.getCodeGenOpts(), *Args, DashX, Diags)
-            && Success;
+  ParseTargetArgs(Res.getTargetOpts(), *Args);
+  Success = ParseCodeGenArgs(Res.getCodeGenOpts(), *Args, DashX, Diags,
+                             Res.getTargetOpts()) && Success;
   ParseHeaderSearchArgs(Res.getHeaderSearchOpts(), *Args);
   if (DashX != IK_AST && DashX != IK_LLVM_IR) {
     ParseLangArgs(*Res.getLangOpts(), *Args, DashX, Diags);
@@ -1672,8 +1818,6 @@ bool CompilerInvocation::CreateFromArgs(CompilerInvocation &Res,
   ParsePreprocessorArgs(Res.getPreprocessorOpts(), *Args, FileMgr, Diags);
   ParsePreprocessorOutputArgs(Res.getPreprocessorOutputOpts(), *Args,
                               Res.getFrontendOpts().ProgramAction);
-  ParseTargetArgs(Res.getTargetOpts(), *Args);
-
   return Success;
 }
 
@@ -1753,8 +1897,7 @@ std::string CompilerInvocation::getModuleHash() const {
   
   // Extend the signature with the target options.
   code = hash_combine(code, TargetOpts->Triple, TargetOpts->CPU,
-                      TargetOpts->ABI, TargetOpts->CXXABI,
-                      TargetOpts->LinkerVersion);
+                      TargetOpts->ABI);
   for (unsigned i = 0, n = TargetOpts->FeaturesAsWritten.size(); i != n; ++i)
     code = hash_combine(code, TargetOpts->FeaturesAsWritten[i]);
 
@@ -1763,7 +1906,6 @@ std::string CompilerInvocation::getModuleHash() const {
   const HeaderSearchOptions &hsOpts = getHeaderSearchOpts();
   code = hash_combine(code, ppOpts.UsePredefines, ppOpts.DetailedRecord);
 
-  std::vector<StringRef> MacroDefs;
   for (std::vector<std::pair<std::string, bool/*isUndef*/> >::const_iterator 
             I = getPreprocessorOpts().Macros.begin(),
          IEnd = getPreprocessorOpts().Macros.end();
@@ -1785,20 +1927,26 @@ std::string CompilerInvocation::getModuleHash() const {
                       hsOpts.UseStandardSystemIncludes,
                       hsOpts.UseStandardCXXIncludes,
                       hsOpts.UseLibcxx);
+  code = hash_combine(code, hsOpts.ResourceDir);
+
+  // Extend the signature with the user build path.
+  code = hash_combine(code, hsOpts.ModuleUserBuildPath);
 
   // Darwin-specific hack: if we have a sysroot, use the contents and
   // modification time of
   //   $sysroot/System/Library/CoreServices/SystemVersion.plist
   // as part of the module hash.
   if (!hsOpts.Sysroot.empty()) {
-    llvm::OwningPtr<llvm::MemoryBuffer> buffer;
     SmallString<128> systemVersionFile;
     systemVersionFile += hsOpts.Sysroot;
     llvm::sys::path::append(systemVersionFile, "System");
     llvm::sys::path::append(systemVersionFile, "Library");
     llvm::sys::path::append(systemVersionFile, "CoreServices");
     llvm::sys::path::append(systemVersionFile, "SystemVersion.plist");
-    if (!llvm::MemoryBuffer::getFile(systemVersionFile.str(), buffer)) {
+
+    llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> buffer =
+        llvm::MemoryBuffer::getFile(systemVersionFile.str());
+    if (buffer) {
       code = hash_combine(code, buffer.get()->getBuffer());
 
       struct stat statBuf;
@@ -1812,10 +1960,11 @@ std::string CompilerInvocation::getModuleHash() const {
 
 namespace clang {
 
-// Declared in clang/Frontend/Utils.h.
-int getLastArgIntValue(const ArgList &Args, OptSpecifier Id, int Default,
-                       DiagnosticsEngine *Diags) {
-  int Res = Default;
+template<typename IntTy>
+static IntTy getLastArgIntValueImpl(const ArgList &Args, OptSpecifier Id,
+                                    IntTy Default,
+                                    DiagnosticsEngine *Diags) {
+  IntTy Res = Default;
   if (Arg *A = Args.getLastArg(Id)) {
     if (StringRef(A->getValue()).getAsInteger(10, Res)) {
       if (Diags)
@@ -1825,4 +1974,60 @@ int getLastArgIntValue(const ArgList &Args, OptSpecifier Id, int Default,
   }
   return Res;
 }
+
+
+// Declared in clang/Frontend/Utils.h.
+int getLastArgIntValue(const ArgList &Args, OptSpecifier Id, int Default,
+                       DiagnosticsEngine *Diags) {
+  return getLastArgIntValueImpl<int>(Args, Id, Default, Diags);
+}
+
+uint64_t getLastArgUInt64Value(const ArgList &Args, OptSpecifier Id,
+                               uint64_t Default,
+                               DiagnosticsEngine *Diags) {
+  return getLastArgIntValueImpl<uint64_t>(Args, Id, Default, Diags);
+}
+
+void BuryPointer(const void *Ptr) {
+  // This function may be called only a small fixed amount of times per each
+  // invocation, otherwise we do actually have a leak which we want to report.
+  // If this function is called more than kGraveYardMaxSize times, the pointers
+  // will not be properly buried and a leak detector will report a leak, which
+  // is what we want in such case.
+  static const size_t kGraveYardMaxSize = 16;
+  LLVM_ATTRIBUTE_UNUSED static const void *GraveYard[kGraveYardMaxSize];
+  static std::atomic<unsigned> GraveYardSize;
+  unsigned Idx = GraveYardSize++;
+  if (Idx >= kGraveYardMaxSize)
+    return;
+  GraveYard[Idx] = Ptr;
+}
+
+IntrusiveRefCntPtr<vfs::FileSystem>
+createVFSFromCompilerInvocation(const CompilerInvocation &CI,
+                                DiagnosticsEngine &Diags) {
+  if (CI.getHeaderSearchOpts().VFSOverlayFiles.empty())
+    return vfs::getRealFileSystem();
+
+  IntrusiveRefCntPtr<vfs::OverlayFileSystem>
+    Overlay(new vfs::OverlayFileSystem(vfs::getRealFileSystem()));
+  // earlier vfs files are on the bottom
+  for (const std::string &File : CI.getHeaderSearchOpts().VFSOverlayFiles) {
+    llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> Buffer =
+        llvm::MemoryBuffer::getFile(File);
+    if (!Buffer) {
+      Diags.Report(diag::err_missing_vfs_overlay_file) << File;
+      return IntrusiveRefCntPtr<vfs::FileSystem>();
+    }
+
+    IntrusiveRefCntPtr<vfs::FileSystem> FS =
+        vfs::getVFSFromYAML(Buffer->release(), /*DiagHandler*/ nullptr);
+    if (!FS.get()) {
+      Diags.Report(diag::err_invalid_vfs_overlay) << File;
+      return IntrusiveRefCntPtr<vfs::FileSystem>();
+    }
+    Overlay->pushOverlay(FS);
+  }
+  return Overlay;
 }
+} // end namespace clang
diff --git a/lib/Frontend/CreateInvocationFromCommandLine.cpp b/lib/Frontend/CreateInvocationFromCommandLine.cpp
index 78f39d4298af..f2f36e4cacb2 100644
--- a/lib/Frontend/CreateInvocationFromCommandLine.cpp
+++ b/lib/Frontend/CreateInvocationFromCommandLine.cpp
@@ -32,7 +32,7 @@ using namespace llvm::opt;
 CompilerInvocation *
 clang::createInvocationFromCommandLine(ArrayRef<const char *> ArgList,
                             IntrusiveRefCntPtr<DiagnosticsEngine> Diags) {
-  if (!Diags.getPtr()) {
+  if (!Diags.get()) {
     // No diagnostics engine was provided, so create our own diagnostics object
     // with the default options.
     Diags = CompilerInstance::createDiagnostics(new DiagnosticOptions);
@@ -47,17 +47,17 @@ clang::createInvocationFromCommandLine(ArrayRef<const char *> ArgList,
 
   // FIXME: We shouldn't have to pass in the path info.
   driver::Driver TheDriver("clang", llvm::sys::getDefaultTargetTriple(),
-                           "a.out", *Diags);
+                           *Diags);
 
   // Don't check that inputs exist, they may have been remapped.
   TheDriver.setCheckInputsExist(false);
 
-  OwningPtr<driver::Compilation> C(TheDriver.BuildCompilation(Args));
+  std::unique_ptr<driver::Compilation> C(TheDriver.BuildCompilation(Args));
 
   // Just print the cc1 options if -### was present.
   if (C->getArgs().hasArg(driver::options::OPT__HASH_HASH_HASH)) {
     C->getJobs().Print(llvm::errs(), "\n", true);
-    return 0;
+    return nullptr;
   }
 
   // We expect to get back exactly one command job, if we didn't something
@@ -68,22 +68,22 @@ clang::createInvocationFromCommandLine(ArrayRef<const char *> ArgList,
     llvm::raw_svector_ostream OS(Msg);
     Jobs.Print(OS, "; ", true);
     Diags->Report(diag::err_fe_expected_compiler_job) << OS.str();
-    return 0;
+    return nullptr;
   }
 
   const driver::Command *Cmd = cast<driver::Command>(*Jobs.begin());
   if (StringRef(Cmd->getCreator().getName()) != "clang") {
     Diags->Report(diag::err_fe_expected_clang_command);
-    return 0;
+    return nullptr;
   }
 
   const ArgStringList &CCArgs = Cmd->getArguments();
-  OwningPtr<CompilerInvocation> CI(new CompilerInvocation());
+  std::unique_ptr<CompilerInvocation> CI(new CompilerInvocation());
   if (!CompilerInvocation::CreateFromArgs(*CI,
                                      const_cast<const char **>(CCArgs.data()),
                                      const_cast<const char **>(CCArgs.data()) +
                                      CCArgs.size(),
                                      *Diags))
-    return 0;
-  return CI.take();
+    return nullptr;
+  return CI.release();
 }
diff --git a/lib/Frontend/DependencyFile.cpp b/lib/Frontend/DependencyFile.cpp
index 4037af9055d5..0b9c0d47dc36 100644
--- a/lib/Frontend/DependencyFile.cpp
+++ b/lib/Frontend/DependencyFile.cpp
@@ -20,6 +20,7 @@
 #include "clang/Lex/LexDiagnostic.h"
 #include "clang/Lex/PPCallbacks.h"
 #include "clang/Lex/Preprocessor.h"
+#include "clang/Serialization/ASTReader.h"
 #include "llvm/ADT/StringSet.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
@@ -28,7 +29,107 @@
 using namespace clang;
 
 namespace {
-class DependencyFileCallback : public PPCallbacks {
+struct DepCollectorPPCallbacks : public PPCallbacks {
+  DependencyCollector &DepCollector;
+  SourceManager &SM;
+  DepCollectorPPCallbacks(DependencyCollector &L, SourceManager &SM)
+      : DepCollector(L), SM(SM) { }
+
+  void FileChanged(SourceLocation Loc, FileChangeReason Reason,
+                   SrcMgr::CharacteristicKind FileType,
+                   FileID PrevFID) override {
+    if (Reason != PPCallbacks::EnterFile)
+      return;
+
+    // Dependency generation really does want to go all the way to the
+    // file entry for a source location to find out what is depended on.
+    // We do not want #line markers to affect dependency generation!
+    const FileEntry *FE =
+        SM.getFileEntryForID(SM.getFileID(SM.getExpansionLoc(Loc)));
+    if (!FE)
+      return;
+
+    StringRef Filename = FE->getName();
+
+    // Remove leading "./" (or ".//" or "././" etc.)
+    while (Filename.size() > 2 && Filename[0] == '.' &&
+           llvm::sys::path::is_separator(Filename[1])) {
+      Filename = Filename.substr(1);
+      while (llvm::sys::path::is_separator(Filename[0]))
+        Filename = Filename.substr(1);
+    }
+
+    DepCollector.maybeAddDependency(Filename, /*FromModule*/false,
+                                   FileType != SrcMgr::C_User,
+                                   /*IsModuleFile*/false, /*IsMissing*/false);
+  }
+
+  void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
+                          StringRef FileName, bool IsAngled,
+                          CharSourceRange FilenameRange, const FileEntry *File,
+                          StringRef SearchPath, StringRef RelativePath,
+                          const Module *Imported) override {
+    if (!File)
+      DepCollector.maybeAddDependency(FileName, /*FromModule*/false,
+                                     /*IsSystem*/false, /*IsModuleFile*/false,
+                                     /*IsMissing*/true);
+    // Files that actually exist are handled by FileChanged.
+  }
+
+  void EndOfMainFile() override {
+    DepCollector.finishedMainFile();
+  }
+};
+
+struct DepCollectorASTListener : public ASTReaderListener {
+  DependencyCollector &DepCollector;
+  DepCollectorASTListener(DependencyCollector &L) : DepCollector(L) { }
+  bool needsInputFileVisitation() override { return true; }
+  bool needsSystemInputFileVisitation() override {
+    return DepCollector.needSystemDependencies();
+  }
+  void visitModuleFile(StringRef Filename) override {
+    DepCollector.maybeAddDependency(Filename, /*FromModule*/true,
+                                   /*IsSystem*/false, /*IsModuleFile*/true,
+                                   /*IsMissing*/false);
+  }
+  bool visitInputFile(StringRef Filename, bool IsSystem,
+                      bool IsOverridden) override {
+    if (IsOverridden)
+      return true;
+
+    DepCollector.maybeAddDependency(Filename, /*FromModule*/true, IsSystem,
+                                   /*IsModuleFile*/false, /*IsMissing*/false);
+    return true;
+  }
+};
+} // end anonymous namespace
+
+void DependencyCollector::maybeAddDependency(StringRef Filename, bool FromModule,
+                                            bool IsSystem, bool IsModuleFile,
+                                            bool IsMissing) {
+  if (Seen.insert(Filename) &&
+      sawDependency(Filename, FromModule, IsSystem, IsModuleFile, IsMissing))
+    Dependencies.push_back(Filename);
+}
+
+bool DependencyCollector::sawDependency(StringRef Filename, bool FromModule,
+                                       bool IsSystem, bool IsModuleFile,
+                                       bool IsMissing) {
+  return Filename != "<built-in>" && (needSystemDependencies() || !IsSystem);
+}
+
+DependencyCollector::~DependencyCollector() { }
+void DependencyCollector::attachToPreprocessor(Preprocessor &PP) {
+  PP.addPPCallbacks(new DepCollectorPPCallbacks(*this, PP.getSourceManager()));
+}
+void DependencyCollector::attachToASTReader(ASTReader &R) {
+  R.addListener(new DepCollectorASTListener(*this));
+}
+
+namespace {
+/// Private implementation for DependencyFileGenerator
+class DFGImpl : public PPCallbacks {
   std::vector<std::string> Files;
   llvm::StringSet<> FilesSet;
   const Preprocessor *PP;
@@ -38,58 +139,84 @@ class DependencyFileCallback : public PPCallbacks {
   bool PhonyTarget;
   bool AddMissingHeaderDeps;
   bool SeenMissingHeader;
+  bool IncludeModuleFiles;
 private:
   bool FileMatchesDepCriteria(const char *Filename,
                               SrcMgr::CharacteristicKind FileType);
-  void AddFilename(StringRef Filename);
   void OutputDependencyFile();
 
 public:
-  DependencyFileCallback(const Preprocessor *_PP,
-                         const DependencyOutputOptions &Opts)
+  DFGImpl(const Preprocessor *_PP, const DependencyOutputOptions &Opts)
     : PP(_PP), OutputFile(Opts.OutputFile), Targets(Opts.Targets),
       IncludeSystemHeaders(Opts.IncludeSystemHeaders),
       PhonyTarget(Opts.UsePhonyTargets),
       AddMissingHeaderDeps(Opts.AddMissingHeaderDeps),
-      SeenMissingHeader(false) {}
-
-  virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
-                           SrcMgr::CharacteristicKind FileType,
-                           FileID PrevFID);
-  virtual void InclusionDirective(SourceLocation HashLoc,
-                                  const Token &IncludeTok,
-                                  StringRef FileName,
-                                  bool IsAngled,
-                                  CharSourceRange FilenameRange,
-                                  const FileEntry *File,
-                                  StringRef SearchPath,
-                                  StringRef RelativePath,
-                                  const Module *Imported);
-
-  virtual void EndOfMainFile() {
+      SeenMissingHeader(false),
+      IncludeModuleFiles(Opts.IncludeModuleFiles) {}
+
+  void FileChanged(SourceLocation Loc, FileChangeReason Reason,
+                   SrcMgr::CharacteristicKind FileType,
+                   FileID PrevFID) override;
+  void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
+                          StringRef FileName, bool IsAngled,
+                          CharSourceRange FilenameRange, const FileEntry *File,
+                          StringRef SearchPath, StringRef RelativePath,
+                          const Module *Imported) override;
+
+  void EndOfMainFile() override {
     OutputDependencyFile();
   }
+
+  void AddFilename(StringRef Filename);
+  bool includeSystemHeaders() const { return IncludeSystemHeaders; }
+  bool includeModuleFiles() const { return IncludeModuleFiles; }
+};
+
+class DFGASTReaderListener : public ASTReaderListener {
+  DFGImpl &Parent;
+public:
+  DFGASTReaderListener(DFGImpl &Parent)
+  : Parent(Parent) { }
+  bool needsInputFileVisitation() override { return true; }
+  bool needsSystemInputFileVisitation() override {
+    return Parent.includeSystemHeaders();
+  }
+  void visitModuleFile(StringRef Filename) override;
+  bool visitInputFile(StringRef Filename, bool isSystem,
+                      bool isOverridden) override;
 };
 }
 
-void clang::AttachDependencyFileGen(Preprocessor &PP,
-                                    const DependencyOutputOptions &Opts) {
+DependencyFileGenerator::DependencyFileGenerator(void *Impl)
+: Impl(Impl) { }
+
+DependencyFileGenerator *DependencyFileGenerator::CreateAndAttachToPreprocessor(
+    clang::Preprocessor &PP, const clang::DependencyOutputOptions &Opts) {
+
   if (Opts.Targets.empty()) {
     PP.getDiagnostics().Report(diag::err_fe_dependency_file_requires_MT);
-    return;
+    return nullptr;
   }
 
   // Disable the "file not found" diagnostic if the -MG option was given.
   if (Opts.AddMissingHeaderDeps)
     PP.SetSuppressIncludeNotFoundError(true);
 
-  PP.addPPCallbacks(new DependencyFileCallback(&PP, Opts));
+  DFGImpl *Callback = new DFGImpl(&PP, Opts);
+  PP.addPPCallbacks(Callback); // PP owns the Callback
+  return new DependencyFileGenerator(Callback);
+}
+
+void DependencyFileGenerator::AttachToASTReader(ASTReader &R) {
+  DFGImpl *I = reinterpret_cast<DFGImpl *>(Impl);
+  assert(I && "missing implementation");
+  R.addListener(new DFGASTReaderListener(*I));
 }
 
 /// FileMatchesDepCriteria - Determine whether the given Filename should be
 /// considered as a dependency.
-bool DependencyFileCallback::FileMatchesDepCriteria(const char *Filename,
-                                          SrcMgr::CharacteristicKind FileType) {
+bool DFGImpl::FileMatchesDepCriteria(const char *Filename,
+                                     SrcMgr::CharacteristicKind FileType) {
   if (strcmp("<built-in>", Filename) == 0)
     return false;
 
@@ -99,10 +226,10 @@ bool DependencyFileCallback::FileMatchesDepCriteria(const char *Filename,
   return FileType == SrcMgr::C_User;
 }
 
-void DependencyFileCallback::FileChanged(SourceLocation Loc,
-                                         FileChangeReason Reason,
-                                         SrcMgr::CharacteristicKind FileType,
-                                         FileID PrevFID) {
+void DFGImpl::FileChanged(SourceLocation Loc,
+                          FileChangeReason Reason,
+                          SrcMgr::CharacteristicKind FileType,
+                          FileID PrevFID) {
   if (Reason != PPCallbacks::EnterFile)
     return;
 
@@ -113,7 +240,7 @@ void DependencyFileCallback::FileChanged(SourceLocation Loc,
 
   const FileEntry *FE =
     SM.getFileEntryForID(SM.getFileID(SM.getExpansionLoc(Loc)));
-  if (FE == 0) return;
+  if (!FE) return;
 
   StringRef Filename = FE->getName();
   if (!FileMatchesDepCriteria(Filename.data(), FileType))
@@ -130,15 +257,15 @@ void DependencyFileCallback::FileChanged(SourceLocation Loc,
   AddFilename(Filename);
 }
 
-void DependencyFileCallback::InclusionDirective(SourceLocation HashLoc,
-                                                const Token &IncludeTok,
-                                                StringRef FileName,
-                                                bool IsAngled,
-                                                CharSourceRange FilenameRange,
-                                                const FileEntry *File,
-                                                StringRef SearchPath,
-                                                StringRef RelativePath,
-                                                const Module *Imported) {
+void DFGImpl::InclusionDirective(SourceLocation HashLoc,
+                                 const Token &IncludeTok,
+                                 StringRef FileName,
+                                 bool IsAngled,
+                                 CharSourceRange FilenameRange,
+                                 const FileEntry *File,
+                                 StringRef SearchPath,
+                                 StringRef RelativePath,
+                                 const Module *Imported) {
   if (!File) {
     if (AddMissingHeaderDeps)
       AddFilename(FileName);
@@ -147,7 +274,7 @@ void DependencyFileCallback::InclusionDirective(SourceLocation HashLoc,
   }
 }
 
-void DependencyFileCallback::AddFilename(StringRef Filename) {
+void DFGImpl::AddFilename(StringRef Filename) {
   if (FilesSet.insert(Filename))
     Files.push_back(Filename);
 }
@@ -164,15 +291,14 @@ static void PrintFilename(raw_ostream &OS, StringRef Filename) {
   }
 }
 
-void DependencyFileCallback::OutputDependencyFile() {
+void DFGImpl::OutputDependencyFile() {
   if (SeenMissingHeader) {
-    bool existed;
-    llvm::sys::fs::remove(OutputFile, existed);
+    llvm::sys::fs::remove(OutputFile);
     return;
   }
 
   std::string Err;
-  llvm::raw_fd_ostream OS(OutputFile.c_str(), Err);
+  llvm::raw_fd_ostream OS(OutputFile.c_str(), Err, llvm::sys::fs::F_Text);
   if (!Err.empty()) {
     PP->getDiagnostics().Report(diag::err_fe_error_opening)
       << OutputFile << Err;
@@ -235,3 +361,17 @@ void DependencyFileCallback::OutputDependencyFile() {
   }
 }
 
+bool DFGASTReaderListener::visitInputFile(llvm::StringRef Filename,
+                                          bool IsSystem, bool IsOverridden) {
+  assert(!IsSystem || needsSystemInputFileVisitation());
+  if (IsOverridden)
+    return true;
+
+  Parent.AddFilename(Filename);
+  return true;
+}
+
+void DFGASTReaderListener::visitModuleFile(llvm::StringRef Filename) {
+  if (Parent.includeModuleFiles())
+    Parent.AddFilename(Filename);
+}
diff --git a/lib/Frontend/DependencyGraph.cpp b/lib/Frontend/DependencyGraph.cpp
index e128d91c4083..051b7f9e1412 100644
--- a/lib/Frontend/DependencyGraph.cpp
+++ b/lib/Frontend/DependencyGraph.cpp
@@ -46,17 +46,13 @@ public:
                           StringRef SysRoot)
     : PP(_PP), OutputFile(OutputFile.str()), SysRoot(SysRoot.str()) { }
 
-  virtual void InclusionDirective(SourceLocation HashLoc,
-                                  const Token &IncludeTok,
-                                  StringRef FileName,
-                                  bool IsAngled,
-                                  CharSourceRange FilenameRange,
-                                  const FileEntry *File,
-                                  StringRef SearchPath,
-                                  StringRef RelativePath,
-                                  const Module *Imported);
+  void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
+                          StringRef FileName, bool IsAngled,
+                          CharSourceRange FilenameRange, const FileEntry *File,
+                          StringRef SearchPath, StringRef RelativePath,
+                          const Module *Imported) override;
 
-  virtual void EndOfMainFile() {
+  void EndOfMainFile() override {
     OutputGraphFile();
   }
   
@@ -83,7 +79,7 @@ void DependencyGraphCallback::InclusionDirective(SourceLocation HashLoc,
   SourceManager &SM = PP->getSourceManager();
   const FileEntry *FromFile
     = SM.getFileEntryForID(SM.getFileID(SM.getExpansionLoc(HashLoc)));
-  if (FromFile == 0) 
+  if (!FromFile)
     return;
 
   Dependencies[FromFile].push_back(File);
@@ -101,7 +97,7 @@ DependencyGraphCallback::writeNodeReference(raw_ostream &OS,
 
 void DependencyGraphCallback::OutputGraphFile() {
   std::string Err;
-  llvm::raw_fd_ostream OS(OutputFile.c_str(), Err);
+  llvm::raw_fd_ostream OS(OutputFile.c_str(), Err, llvm::sys::fs::F_Text);
   if (!Err.empty()) {
     PP->getDiagnostics().Report(diag::err_fe_error_opening)
       << OutputFile << Err;
diff --git a/lib/Frontend/DiagnosticRenderer.cpp b/lib/Frontend/DiagnosticRenderer.cpp
index 4eee59548c82..cff32b852bf4 100644
--- a/lib/Frontend/DiagnosticRenderer.cpp
+++ b/lib/Frontend/DiagnosticRenderer.cpp
@@ -79,10 +79,10 @@ class FixitReceiver : public edit::EditsReceiver {
 public:
   FixitReceiver(SmallVectorImpl<FixItHint> &MergedFixits)
     : MergedFixits(MergedFixits) { }
-  virtual void insert(SourceLocation loc, StringRef text) {
+  void insert(SourceLocation loc, StringRef text) override {
     MergedFixits.push_back(FixItHint::CreateInsertion(loc, text));
   }
-  virtual void replace(CharSourceRange range, StringRef text) {
+  void replace(CharSourceRange range, StringRef text) override {
     MergedFixits.push_back(FixItHint::CreateReplacement(range, text));
   }
 };
@@ -186,10 +186,16 @@ void DiagnosticRenderer::emitStoredDiagnostic(StoredDiagnostic &Diag) {
   emitDiagnostic(Diag.getLocation(), Diag.getLevel(), Diag.getMessage(),
                  Diag.getRanges(), Diag.getFixIts(),
                  Diag.getLocation().isValid() ? &Diag.getLocation().getManager()
-                                              : 0,
+                                              : nullptr,
                  &Diag);
 }
 
+void DiagnosticRenderer::emitBasicNote(StringRef Message) {
+  emitDiagnosticMessage(
+      SourceLocation(), PresumedLoc(), DiagnosticsEngine::Note, Message,
+      ArrayRef<CharSourceRange>(), nullptr, DiagOrStoredDiag());
+}
+
 /// \brief Prints an include stack when appropriate for a particular
 /// diagnostic level and location.
 ///
@@ -499,12 +505,10 @@ DiagnosticNoteRenderer::emitBuildingModuleLocation(SourceLocation Loc,
   // Generate a note indicating the include location.
   SmallString<200> MessageStorage;
   llvm::raw_svector_ostream Message(MessageStorage);
-  Message << "while building module '" << ModuleName << "' imported from "
-          << PLoc.getFilename() << ':' << PLoc.getLine() << ":";
+  if (PLoc.getFilename())
+    Message << "while building module '" << ModuleName << "' imported from "
+            << PLoc.getFilename() << ':' << PLoc.getLine() << ":";
+  else
+    Message << "while building module '" << ModuleName << ":";
   emitNote(Loc, Message.str(), &SM);
 }
-
-
-void DiagnosticNoteRenderer::emitBasicNote(StringRef Message) {
-  emitNote(SourceLocation(), Message, 0);  
-}
diff --git a/lib/Frontend/FrontendAction.cpp b/lib/Frontend/FrontendAction.cpp
index 075fe93d5841..791017924d69 100644
--- a/lib/Frontend/FrontendAction.cpp
+++ b/lib/Frontend/FrontendAction.cpp
@@ -12,12 +12,12 @@
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/DeclGroup.h"
 #include "clang/Frontend/ASTUnit.h"
-#include "clang/Frontend/ChainedIncludesSource.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/FrontendDiagnostic.h"
 #include "clang/Frontend/FrontendPluginRegistry.h"
 #include "clang/Frontend/LayoutOverrideSource.h"
 #include "clang/Frontend/MultiplexConsumer.h"
+#include "clang/Frontend/Utils.h"
 #include "clang/Lex/HeaderSearch.h"
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Parse/ParseAST.h"
@@ -29,42 +29,49 @@
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/raw_ostream.h"
-#include "llvm/Support/system_error.h"
+#include <system_error>
 using namespace clang;
 
+template class llvm::Registry<clang::PluginASTAction>;
+
 namespace {
 
 class DelegatingDeserializationListener : public ASTDeserializationListener {
   ASTDeserializationListener *Previous;
+  bool DeletePrevious;
 
 public:
   explicit DelegatingDeserializationListener(
-                                           ASTDeserializationListener *Previous)
-    : Previous(Previous) { }
+      ASTDeserializationListener *Previous, bool DeletePrevious)
+      : Previous(Previous), DeletePrevious(DeletePrevious) {}
+  virtual ~DelegatingDeserializationListener() {
+    if (DeletePrevious)
+      delete Previous;
+  }
 
-  virtual void ReaderInitialized(ASTReader *Reader) {
+  void ReaderInitialized(ASTReader *Reader) override {
     if (Previous)
       Previous->ReaderInitialized(Reader);
   }
-  virtual void IdentifierRead(serialization::IdentID ID,
-                              IdentifierInfo *II) {
+  void IdentifierRead(serialization::IdentID ID,
+                      IdentifierInfo *II) override {
     if (Previous)
       Previous->IdentifierRead(ID, II);
   }
-  virtual void TypeRead(serialization::TypeIdx Idx, QualType T) {
+  void TypeRead(serialization::TypeIdx Idx, QualType T) override {
     if (Previous)
       Previous->TypeRead(Idx, T);
   }
-  virtual void DeclRead(serialization::DeclID ID, const Decl *D) {
+  void DeclRead(serialization::DeclID ID, const Decl *D) override {
     if (Previous)
       Previous->DeclRead(ID, D);
   }
-  virtual void SelectorRead(serialization::SelectorID ID, Selector Sel) {
+  void SelectorRead(serialization::SelectorID ID, Selector Sel) override {
     if (Previous)
       Previous->SelectorRead(ID, Sel);
   }
-  virtual void MacroDefinitionRead(serialization::PreprocessedEntityID PPID, 
-                                   MacroDefinition *MD) {
+  void MacroDefinitionRead(serialization::PreprocessedEntityID PPID,
+                           MacroDefinition *MD) override {
     if (Previous)
       Previous->MacroDefinitionRead(PPID, MD);
   }
@@ -73,10 +80,11 @@ public:
 /// \brief Dumps deserialized declarations.
 class DeserializedDeclsDumper : public DelegatingDeserializationListener {
 public:
-  explicit DeserializedDeclsDumper(ASTDeserializationListener *Previous)
-    : DelegatingDeserializationListener(Previous) { }
+  explicit DeserializedDeclsDumper(ASTDeserializationListener *Previous,
+                                   bool DeletePrevious)
+      : DelegatingDeserializationListener(Previous, DeletePrevious) {}
 
-  virtual void DeclRead(serialization::DeclID ID, const Decl *D) {
+  void DeclRead(serialization::DeclID ID, const Decl *D) override {
     llvm::outs() << "PCH DECL: " << D->getDeclKindName();
     if (const NamedDecl *ND = dyn_cast<NamedDecl>(D))
       llvm::outs() << " - " << *ND;
@@ -95,11 +103,12 @@ class DeserializedDeclsChecker : public DelegatingDeserializationListener {
 public:
   DeserializedDeclsChecker(ASTContext &Ctx,
                            const std::set<std::string> &NamesToCheck,
-                           ASTDeserializationListener *Previous)
-    : DelegatingDeserializationListener(Previous),
-      Ctx(Ctx), NamesToCheck(NamesToCheck) { }
+                           ASTDeserializationListener *Previous,
+                           bool DeletePrevious)
+      : DelegatingDeserializationListener(Previous, DeletePrevious), Ctx(Ctx),
+        NamesToCheck(NamesToCheck) {}
 
-  virtual void DeclRead(serialization::DeclID ID, const Decl *D) {
+  void DeclRead(serialization::DeclID ID, const Decl *D) override {
     if (const NamedDecl *ND = dyn_cast<NamedDecl>(D))
       if (NamesToCheck.find(ND->getNameAsString()) != NamesToCheck.end()) {
         unsigned DiagID
@@ -115,7 +124,7 @@ public:
 
 } // end anonymous namespace
 
-FrontendAction::FrontendAction() : Instance(0) {}
+FrontendAction::FrontendAction() : Instance(nullptr) {}
 
 FrontendAction::~FrontendAction() {}
 
@@ -129,7 +138,7 @@ ASTConsumer* FrontendAction::CreateWrappedASTConsumer(CompilerInstance &CI,
                                                       StringRef InFile) {
   ASTConsumer* Consumer = CreateASTConsumer(CI, InFile);
   if (!Consumer)
-    return 0;
+    return nullptr;
 
   if (CI.getFrontendOpts().AddPluginActions.size() == 0)
     return Consumer;
@@ -147,7 +156,7 @@ ASTConsumer* FrontendAction::CreateWrappedASTConsumer(CompilerInstance &CI,
         ie = FrontendPluginRegistry::end();
         it != ie; ++it) {
       if (it->getName() == CI.getFrontendOpts().AddPluginActions[i]) {
-        OwningPtr<PluginASTAction> P(it->instantiate());
+        std::unique_ptr<PluginASTAction> P(it->instantiate());
         FrontendAction* c = P.get();
         if (P->ParseArgs(CI, CI.getFrontendOpts().AddPluginArgs[i]))
           Consumers.push_back(c->CreateASTConsumer(CI, InFile));
@@ -158,7 +167,6 @@ ASTConsumer* FrontendAction::CreateWrappedASTConsumer(CompilerInstance &CI,
   return new MultiplexConsumer(Consumers);
 }
 
-
 bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
                                      const FrontendInputFile &Input) {
   assert(!Instance && "Already processing a source file!");
@@ -180,7 +188,7 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
            "This action does not have AST file support!");
 
     IntrusiveRefCntPtr<DiagnosticsEngine> Diags(&CI.getDiagnostics());
-    std::string Error;
+
     ASTUnit *AST = ASTUnit::LoadFromASTFile(InputFile, Diags,
                                             CI.getFileSystemOpts());
     if (!AST)
@@ -189,7 +197,7 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
     setCurrentInput(Input, AST);
 
     // Inform the diagnostic client we are processing a source file.
-    CI.getDiagnosticClient().BeginSourceFile(CI.getLangOpts(), 0);
+    CI.getDiagnosticClient().BeginSourceFile(CI.getLangOpts(), nullptr);
     HasBegunSourceFile = true;
 
     // Set the shared objects, these are reset when we finish processing the
@@ -211,6 +219,15 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
     return true;
   }
 
+  if (!CI.hasVirtualFileSystem()) {
+    if (IntrusiveRefCntPtr<vfs::FileSystem> VFS =
+          createVFSFromCompilerInvocation(CI.getInvocation(),
+                                          CI.getDiagnostics()))
+      CI.setVirtualFileSystem(VFS);
+    else
+      goto failure;
+  }
+
   // Set up the file and source managers, if needed.
   if (!CI.hasFileManager())
     CI.createFileManager();
@@ -223,13 +240,17 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
            "This action does not have IR file support!");
 
     // Inform the diagnostic client we are processing a source file.
-    CI.getDiagnosticClient().BeginSourceFile(CI.getLangOpts(), 0);
+    CI.getDiagnosticClient().BeginSourceFile(CI.getLangOpts(), nullptr);
     HasBegunSourceFile = true;
 
     // Initialize the action.
     if (!BeginSourceFileAction(CI, InputFile))
       goto failure;
 
+    // Initialize the main file entry.
+    if (!CI.InitializeSourceManager(CurrentInput))
+      goto failure;
+
     return true;
   }
 
@@ -240,7 +261,7 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
     PreprocessorOptions &PPOpts = CI.getPreprocessorOpts();
     StringRef PCHInclude = PPOpts.ImplicitPCHInclude;
     if (const DirectoryEntry *PCHDir = FileMgr.getDirectory(PCHInclude)) {
-      llvm::error_code EC;
+      std::error_code EC;
       SmallString<128> DirNative;
       llvm::sys::path::native(PCHDir->getName(), DirNative);
       bool Found = false;
@@ -265,7 +286,7 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
   }
 
   // Set up the preprocessor.
-  CI.createPreprocessor();
+  CI.createPreprocessor(getTranslationUnitKind());
 
   // Inform the diagnostic client we are processing a source file.
   CI.getDiagnosticClient().BeginSourceFile(CI.getLangOpts(),
@@ -276,13 +297,18 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
   if (!BeginSourceFileAction(CI, InputFile))
     goto failure;
 
+  // Initialize the main file entry. It is important that this occurs after
+  // BeginSourceFileAction, which may change CurrentInput during module builds.
+  if (!CI.InitializeSourceManager(CurrentInput))
+    goto failure;
+
   // Create the AST context and consumer unless this is a preprocessor only
   // action.
   if (!usesPreprocessorOnly()) {
     CI.createASTContext();
 
-    OwningPtr<ASTConsumer> Consumer(
-                                   CreateWrappedASTConsumer(CI, InputFile));
+    std::unique_ptr<ASTConsumer> Consumer(
+        CreateWrappedASTConsumer(CI, InputFile));
     if (!Consumer)
       goto failure;
 
@@ -290,35 +316,40 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
     
     if (!CI.getPreprocessorOpts().ChainedIncludes.empty()) {
       // Convert headers to PCH and chain them.
-      OwningPtr<ExternalASTSource> source;
-      source.reset(ChainedIncludesSource::create(CI));
+      IntrusiveRefCntPtr<ExternalSemaSource> source, FinalReader;
+      source = createChainedIncludesSource(CI, FinalReader);
       if (!source)
         goto failure;
-      CI.setModuleManager(static_cast<ASTReader*>(
-         &static_cast<ChainedIncludesSource*>(source.get())->getFinalReader()));
+      CI.setModuleManager(static_cast<ASTReader *>(FinalReader.get()));
       CI.getASTContext().setExternalSource(source);
-
     } else if (!CI.getPreprocessorOpts().ImplicitPCHInclude.empty()) {
       // Use PCH.
       assert(hasPCHSupport() && "This action does not have PCH support!");
       ASTDeserializationListener *DeserialListener =
           Consumer->GetASTDeserializationListener();
-      if (CI.getPreprocessorOpts().DumpDeserializedPCHDecls)
-        DeserialListener = new DeserializedDeclsDumper(DeserialListener);
-      if (!CI.getPreprocessorOpts().DeserializedPCHDeclsToErrorOn.empty())
-        DeserialListener = new DeserializedDeclsChecker(CI.getASTContext(),
-                         CI.getPreprocessorOpts().DeserializedPCHDeclsToErrorOn,
-                                                        DeserialListener);
+      bool DeleteDeserialListener = false;
+      if (CI.getPreprocessorOpts().DumpDeserializedPCHDecls) {
+        DeserialListener = new DeserializedDeclsDumper(DeserialListener,
+                                                       DeleteDeserialListener);
+        DeleteDeserialListener = true;
+      }
+      if (!CI.getPreprocessorOpts().DeserializedPCHDeclsToErrorOn.empty()) {
+        DeserialListener = new DeserializedDeclsChecker(
+            CI.getASTContext(),
+            CI.getPreprocessorOpts().DeserializedPCHDeclsToErrorOn,
+            DeserialListener, DeleteDeserialListener);
+        DeleteDeserialListener = true;
+      }
       CI.createPCHExternalASTSource(
-                                CI.getPreprocessorOpts().ImplicitPCHInclude,
-                                CI.getPreprocessorOpts().DisablePCHValidation,
-                            CI.getPreprocessorOpts().AllowPCHWithCompilerErrors,
-                                DeserialListener);
+          CI.getPreprocessorOpts().ImplicitPCHInclude,
+          CI.getPreprocessorOpts().DisablePCHValidation,
+          CI.getPreprocessorOpts().AllowPCHWithCompilerErrors, DeserialListener,
+          DeleteDeserialListener);
       if (!CI.getASTContext().getExternalSource())
         goto failure;
     }
 
-    CI.setASTConsumer(Consumer.take());
+    CI.setASTConsumer(Consumer.release());
     if (!CI.hasASTConsumer())
       goto failure;
   }
@@ -327,50 +358,56 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
   // source.
   if (!CI.hasASTContext() || !CI.getASTContext().getExternalSource()) {
     Preprocessor &PP = CI.getPreprocessor();
+
+    // If modules are enabled, create the module manager before creating
+    // any builtins, so that all declarations know that they might be
+    // extended by an external source.
+    if (CI.getLangOpts().Modules)
+      CI.createModuleManager();
+
     PP.getBuiltinInfo().InitializeBuiltins(PP.getIdentifierTable(),
                                            PP.getLangOpts());
+  } else {
+    // FIXME: If this is a problem, recover from it by creating a multiplex
+    // source.
+    assert((!CI.getLangOpts().Modules || CI.getModuleManager()) &&
+           "modules enabled but created an external source that "
+           "doesn't support modules");
   }
 
   // If there is a layout overrides file, attach an external AST source that
   // provides the layouts from that file.
   if (!CI.getFrontendOpts().OverrideRecordLayoutsFile.empty() && 
       CI.hasASTContext() && !CI.getASTContext().getExternalSource()) {
-    OwningPtr<ExternalASTSource> 
+    IntrusiveRefCntPtr<ExternalASTSource> 
       Override(new LayoutOverrideSource(
                      CI.getFrontendOpts().OverrideRecordLayoutsFile));
     CI.getASTContext().setExternalSource(Override);
   }
-  
+
   return true;
 
   // If we failed, reset state since the client will not end up calling the
   // matching EndSourceFile().
   failure:
   if (isCurrentFileAST()) {
-    CI.setASTContext(0);
-    CI.setPreprocessor(0);
-    CI.setSourceManager(0);
-    CI.setFileManager(0);
+    CI.setASTContext(nullptr);
+    CI.setPreprocessor(nullptr);
+    CI.setSourceManager(nullptr);
+    CI.setFileManager(nullptr);
   }
 
   if (HasBegunSourceFile)
     CI.getDiagnosticClient().EndSourceFile();
   CI.clearOutputFiles(/*EraseFiles=*/true);
   setCurrentInput(FrontendInputFile());
-  setCompilerInstance(0);
+  setCompilerInstance(nullptr);
   return false;
 }
 
 bool FrontendAction::Execute() {
   CompilerInstance &CI = getCompilerInstance();
 
-  // Initialize the main file entry. This needs to be delayed until after PCH
-  // has loaded.
-  if (!isCurrentFileAST()) {
-    if (!CI.InitializeSourceManager(getCurrentInput()))
-      return false;
-  }
-
   if (CI.hasFrontendTimer()) {
     llvm::TimeRegion Timer(CI.getFrontendTimer());
     ExecuteAction();
@@ -398,22 +435,22 @@ void FrontendAction::EndSourceFile() {
   // Finalize the action.
   EndSourceFileAction();
 
-  // Release the consumer and the AST, in that order since the consumer may
-  // perform actions in its destructor which require the context.
+  // Sema references the ast consumer, so reset sema first.
   //
   // FIXME: There is more per-file stuff we could just drop here?
-  if (CI.getFrontendOpts().DisableFree) {
-    CI.takeASTConsumer();
+  bool DisableFree = CI.getFrontendOpts().DisableFree;
+  if (DisableFree) {
     if (!isCurrentFileAST()) {
-      CI.takeSema();
+      CI.resetAndLeakSema();
       CI.resetAndLeakASTContext();
     }
+    BuryPointer(CI.takeASTConsumer());
   } else {
     if (!isCurrentFileAST()) {
-      CI.setSema(0);
-      CI.setASTContext(0);
+      CI.setSema(nullptr);
+      CI.setASTContext(nullptr);
     }
-    CI.setASTConsumer(0);
+    CI.setASTConsumer(nullptr);
   }
 
   // Inform the preprocessor we are done.
@@ -433,15 +470,16 @@ void FrontendAction::EndSourceFile() {
   // FrontendAction.
   CI.clearOutputFiles(/*EraseFiles=*/shouldEraseOutputFiles());
 
+  // FIXME: Only do this if DisableFree is set.
   if (isCurrentFileAST()) {
-    CI.takeSema();
+    CI.resetAndLeakSema();
     CI.resetAndLeakASTContext();
     CI.resetAndLeakPreprocessor();
     CI.resetAndLeakSourceManager();
     CI.resetAndLeakFileManager();
   }
 
-  setCompilerInstance(0);
+  setCompilerInstance(nullptr);
   setCurrentInput(FrontendInputFile());
 }
 
@@ -465,7 +503,7 @@ void ASTFrontendAction::ExecuteAction() {
     CI.createCodeCompletionConsumer();
 
   // Use a code completion consumer?
-  CodeCompleteConsumer *CompletionConsumer = 0;
+  CodeCompleteConsumer *CompletionConsumer = nullptr;
   if (CI.hasCodeCompletionConsumer())
     CompletionConsumer = &CI.getCodeCompletionConsumer();
 
diff --git a/lib/Frontend/FrontendActions.cpp b/lib/Frontend/FrontendActions.cpp
index a3ab1be4a97a..6dcaf382c3c4 100644
--- a/lib/Frontend/FrontendActions.cpp
+++ b/lib/Frontend/FrontendActions.cpp
@@ -21,11 +21,11 @@
 #include "clang/Parse/Parser.h"
 #include "clang/Serialization/ASTReader.h"
 #include "clang/Serialization/ASTWriter.h"
-#include "llvm/ADT/OwningPtr.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/raw_ostream.h"
-#include "llvm/Support/system_error.h"
+#include <memory>
+#include <system_error>
 
 using namespace clang;
 
@@ -49,7 +49,7 @@ ASTConsumer *ASTPrintAction::CreateASTConsumer(CompilerInstance &CI,
                                                StringRef InFile) {
   if (raw_ostream *OS = CI.createDefaultOutputFile(false, InFile))
     return CreateASTPrinter(OS, CI.getFrontendOpts().ASTDumpFilter);
-  return 0;
+  return nullptr;
 }
 
 ASTConsumer *ASTDumpAction::CreateASTConsumer(CompilerInstance &CI,
@@ -77,13 +77,14 @@ ASTConsumer *GeneratePCHAction::CreateASTConsumer(CompilerInstance &CI,
                                                   StringRef InFile) {
   std::string Sysroot;
   std::string OutputFile;
-  raw_ostream *OS = 0;
+  raw_ostream *OS = nullptr;
   if (ComputeASTConsumerArguments(CI, InFile, Sysroot, OutputFile, OS))
-    return 0;
+    return nullptr;
 
   if (!CI.getFrontendOpts().RelocatablePCH)
     Sysroot.clear();
-  return new PCHGenerator(CI.getPreprocessor(), OutputFile, 0, Sysroot, OS);
+  return new PCHGenerator(CI.getPreprocessor(), OutputFile, nullptr, Sysroot,
+                          OS);
 }
 
 bool GeneratePCHAction::ComputeASTConsumerArguments(CompilerInstance &CI,
@@ -114,10 +115,10 @@ ASTConsumer *GenerateModuleAction::CreateASTConsumer(CompilerInstance &CI,
                                                      StringRef InFile) {
   std::string Sysroot;
   std::string OutputFile;
-  raw_ostream *OS = 0;
+  raw_ostream *OS = nullptr;
   if (ComputeASTConsumerArguments(CI, InFile, Sysroot, OutputFile, OS))
-    return 0;
-  
+    return nullptr;
+
   return new PCHGenerator(CI.getPreprocessor(), OutputFile, Module, 
                           Sysroot, OS);
 }
@@ -128,21 +129,38 @@ operator+=(SmallVectorImpl<char> &Includes, StringRef RHS) {
   return Includes;
 }
 
-static void addHeaderInclude(StringRef HeaderName,
-                             SmallVectorImpl<char> &Includes,
-                             const LangOptions &LangOpts) {
+static std::error_code addHeaderInclude(StringRef HeaderName,
+                                        SmallVectorImpl<char> &Includes,
+                                        const LangOptions &LangOpts,
+                                        bool IsExternC) {
+  if (IsExternC && LangOpts.CPlusPlus)
+    Includes += "extern \"C\" {\n";
   if (LangOpts.ObjC1)
     Includes += "#import \"";
   else
     Includes += "#include \"";
-  Includes += HeaderName;
+  // Use an absolute path for the include; there's no reason to think that
+  // a relative path will work (. might not be on our include path) or that
+  // it will find the same file.
+  if (llvm::sys::path::is_absolute(HeaderName)) {
+    Includes += HeaderName;
+  } else {
+    SmallString<256> Header = HeaderName;
+    if (std::error_code Err = llvm::sys::fs::make_absolute(Header))
+      return Err;
+    Includes += Header;
+  }
   Includes += "\"\n";
+  if (IsExternC && LangOpts.CPlusPlus)
+    Includes += "}\n";
+  return std::error_code();
 }
 
-static void addHeaderInclude(const FileEntry *Header,
-                             SmallVectorImpl<char> &Includes,
-                             const LangOptions &LangOpts) {
-  addHeaderInclude(Header->getName(), Includes, LangOpts);
+static std::error_code addHeaderInclude(const FileEntry *Header,
+                                        SmallVectorImpl<char> &Includes,
+                                        const LangOptions &LangOpts,
+                                        bool IsExternC) {
+  return addHeaderInclude(Header->getName(), Includes, LangOpts, IsExternC);
 }
 
 /// \brief Collect the set of header includes needed to construct the given 
@@ -152,20 +170,21 @@ static void addHeaderInclude(const FileEntry *Header,
 ///
 /// \param Includes Will be augmented with the set of \#includes or \#imports
 /// needed to load all of the named headers.
-static void collectModuleHeaderIncludes(const LangOptions &LangOpts,
-                                        FileManager &FileMgr,
-                                        ModuleMap &ModMap,
-                                        clang::Module *Module,
-                                        SmallVectorImpl<char> &Includes) {
+static std::error_code
+collectModuleHeaderIncludes(const LangOptions &LangOpts, FileManager &FileMgr,
+                            ModuleMap &ModMap, clang::Module *Module,
+                            SmallVectorImpl<char> &Includes) {
   // Don't collect any headers for unavailable modules.
   if (!Module->isAvailable())
-    return;
+    return std::error_code();
 
   // Add includes for each of these headers.
   for (unsigned I = 0, N = Module->NormalHeaders.size(); I != N; ++I) {
     const FileEntry *Header = Module->NormalHeaders[I];
     Module->addTopHeader(Header);
-    addHeaderInclude(Header, Includes, LangOpts);
+    if (std::error_code Err =
+            addHeaderInclude(Header, Includes, LangOpts, Module->IsExternC))
+      return Err;
   }
   // Note that Module->PrivateHeaders will not be a TopHeader.
 
@@ -173,11 +192,13 @@ static void collectModuleHeaderIncludes(const LangOptions &LangOpts,
     Module->addTopHeader(UmbrellaHeader);
     if (Module->Parent) {
       // Include the umbrella header for submodules.
-      addHeaderInclude(UmbrellaHeader, Includes, LangOpts);
+      if (std::error_code Err = addHeaderInclude(UmbrellaHeader, Includes,
+                                                 LangOpts, Module->IsExternC))
+        return Err;
     }
   } else if (const DirectoryEntry *UmbrellaDir = Module->getUmbrellaDir()) {
     // Add all of the headers we find in this subdirectory.
-    llvm::error_code EC;
+    std::error_code EC;
     SmallString<128> DirNative;
     llvm::sys::path::native(UmbrellaDir->getName(), DirNative);
     for (llvm::sys::fs::recursive_directory_iterator Dir(DirNative.str(), EC), 
@@ -193,21 +214,30 @@ static void collectModuleHeaderIncludes(const LangOptions &LangOpts,
       // If this header is marked 'unavailable' in this module, don't include 
       // it.
       if (const FileEntry *Header = FileMgr.getFile(Dir->path())) {
-        if (ModMap.isHeaderInUnavailableModule(Header))
+        if (ModMap.isHeaderUnavailableInModule(Header, Module))
           continue;
         Module->addTopHeader(Header);
       }
       
-      // Include this header umbrella header for submodules.
-      addHeaderInclude(Dir->path(), Includes, LangOpts);
+      // Include this header as part of the umbrella directory.
+      if (std::error_code Err = addHeaderInclude(Dir->path(), Includes,
+                                                 LangOpts, Module->IsExternC))
+        return Err;
     }
+
+    if (EC)
+      return EC;
   }
   
   // Recurse into submodules.
   for (clang::Module::submodule_iterator Sub = Module->submodule_begin(),
                                       SubEnd = Module->submodule_end();
        Sub != SubEnd; ++Sub)
-    collectModuleHeaderIncludes(LangOpts, FileMgr, ModMap, *Sub, Includes);
+    if (std::error_code Err = collectModuleHeaderIncludes(
+            LangOpts, FileMgr, ModMap, *Sub, Includes))
+      return Err;
+
+  return std::error_code();
 }
 
 bool GenerateModuleAction::BeginSourceFileAction(CompilerInstance &CI, 
@@ -234,7 +264,15 @@ bool GenerateModuleAction::BeginSourceFileAction(CompilerInstance &CI,
     // map with a single module (the common case).
     return false;
   }
-  
+
+  // If we're being run from the command-line, the module build stack will not
+  // have been filled in yet, so complete it now in order to allow us to detect
+  // module cycles.
+  SourceManager &SourceMgr = CI.getSourceManager();
+  if (SourceMgr.getModuleBuildStack().empty())
+    SourceMgr.pushModuleBuildStack(CI.getLangOpts().CurrentModule,
+                                   FullSourceLoc(SourceLocation(), SourceMgr));
+
   // Dig out the module definition.
   Module = HS.lookupModule(CI.getLangOpts().CurrentModule, 
                            /*AllowSearch=*/false);
@@ -247,28 +285,51 @@ bool GenerateModuleAction::BeginSourceFileAction(CompilerInstance &CI,
 
   // Check whether we can build this module at all.
   clang::Module::Requirement Requirement;
-  if (!Module->isAvailable(CI.getLangOpts(), CI.getTarget(), Requirement)) {
-    CI.getDiagnostics().Report(diag::err_module_unavailable)
-      << Module->getFullModuleName()
-      << Requirement.second << Requirement.first;
+  clang::Module::HeaderDirective MissingHeader;
+  if (!Module->isAvailable(CI.getLangOpts(), CI.getTarget(), Requirement,
+                           MissingHeader)) {
+    if (MissingHeader.FileNameLoc.isValid()) {
+      CI.getDiagnostics().Report(MissingHeader.FileNameLoc,
+                                 diag::err_module_header_missing)
+        << MissingHeader.IsUmbrella << MissingHeader.FileName;
+    } else {
+      CI.getDiagnostics().Report(diag::err_module_unavailable)
+        << Module->getFullModuleName()
+        << Requirement.second << Requirement.first;
+    }
 
     return false;
   }
 
+  if (!ModuleMapForUniquing)
+    ModuleMapForUniquing = ModuleMap;
+  Module->ModuleMap = ModuleMapForUniquing;
+  assert(Module->ModuleMap && "missing module map file");
+
   FileManager &FileMgr = CI.getFileManager();
 
   // Collect the set of #includes we need to build the module.
   SmallString<256> HeaderContents;
+  std::error_code Err = std::error_code();
   if (const FileEntry *UmbrellaHeader = Module->getUmbrellaHeader())
-    addHeaderInclude(UmbrellaHeader, HeaderContents, CI.getLangOpts());
-  collectModuleHeaderIncludes(CI.getLangOpts(), FileMgr,
-    CI.getPreprocessor().getHeaderSearchInfo().getModuleMap(),
-    Module, HeaderContents);
+    Err = addHeaderInclude(UmbrellaHeader, HeaderContents, CI.getLangOpts(),
+                           Module->IsExternC);
+  if (!Err)
+    Err = collectModuleHeaderIncludes(
+        CI.getLangOpts(), FileMgr,
+        CI.getPreprocessor().getHeaderSearchInfo().getModuleMap(), Module,
+        HeaderContents);
+
+  if (Err) {
+    CI.getDiagnostics().Report(diag::err_module_cannot_create_includes)
+      << Module->getFullModuleName() << Err.message();
+    return false;
+  }
 
   llvm::MemoryBuffer *InputBuffer =
       llvm::MemoryBuffer::getMemBufferCopy(HeaderContents,
                                            Module::getModuleInputBufferName());
-  // Ownership of InputBuffer will be transfered to the SourceManager.
+  // Ownership of InputBuffer will be transferred to the SourceManager.
   setCurrentInput(FrontendInputFile(InputBuffer, getCurrentFileKind(),
                                     Module->IsSystem));
   return true;
@@ -283,10 +344,9 @@ bool GenerateModuleAction::ComputeASTConsumerArguments(CompilerInstance &CI,
   // in the module cache.
   if (CI.getFrontendOpts().OutputFile.empty()) {
     HeaderSearch &HS = CI.getPreprocessor().getHeaderSearchInfo();
-    SmallString<256> ModuleFileName(HS.getModuleCachePath());
-    llvm::sys::path::append(ModuleFileName, 
-                            CI.getLangOpts().CurrentModule + ".pcm");
-    CI.getFrontendOpts().OutputFile = ModuleFileName.str();
+    CI.getFrontendOpts().OutputFile =
+        HS.getModuleFileName(CI.getLangOpts().CurrentModule,
+                             ModuleMapForUniquing->getName());
   }
   
   // We use createOutputFile here because this is exposed via libclang, and we
@@ -313,6 +373,30 @@ ASTConsumer *DumpModuleInfoAction::CreateASTConsumer(CompilerInstance &CI,
   return new ASTConsumer();
 }
 
+ASTConsumer *VerifyPCHAction::CreateASTConsumer(CompilerInstance &CI,
+                                                StringRef InFile) {
+  return new ASTConsumer();
+}
+
+void VerifyPCHAction::ExecuteAction() {
+  CompilerInstance &CI = getCompilerInstance();
+  bool Preamble = CI.getPreprocessorOpts().PrecompiledPreambleBytes.first != 0;
+  const std::string &Sysroot = CI.getHeaderSearchOpts().Sysroot;
+  std::unique_ptr<ASTReader> Reader(
+      new ASTReader(CI.getPreprocessor(), CI.getASTContext(),
+                    Sysroot.empty() ? "" : Sysroot.c_str(),
+                    /*DisableValidation*/ false,
+                    /*AllowPCHWithCompilerErrors*/ false,
+                    /*AllowConfigurationMismatch*/ true,
+                    /*ValidateSystemInputs*/ true));
+
+  Reader->ReadAST(getCurrentFile(),
+                  Preamble ? serialization::MK_Preamble
+                           : serialization::MK_PCH,
+                  SourceLocation(),
+                  ASTReader::ARR_ConfigurationMismatch);
+}
+
 namespace {
   /// \brief AST reader listener that dumps module information for a module
   /// file.
@@ -325,7 +409,7 @@ namespace {
 #define DUMP_BOOLEAN(Value, Text)                       \
     Out.indent(4) << Text << ": " << (Value? "Yes" : "No") << "\n"
 
-    virtual bool ReadFullVersionInformation(StringRef FullVersion) {
+    bool ReadFullVersionInformation(StringRef FullVersion) override {
       Out.indent(2)
         << "Generated by "
         << (FullVersion == getClangFullRepositoryVersion()? "this"
@@ -334,8 +418,15 @@ namespace {
       return ASTReaderListener::ReadFullVersionInformation(FullVersion);
     }
 
-    virtual bool ReadLanguageOptions(const LangOptions &LangOpts,
-                                     bool Complain) {
+    void ReadModuleName(StringRef ModuleName) override {
+      Out.indent(2) << "Module name: " << ModuleName << "\n";
+    }
+    void ReadModuleMapFile(StringRef ModuleMapPath) override {
+      Out.indent(2) << "Module map file: " << ModuleMapPath << "\n";
+    }
+
+    bool ReadLanguageOptions(const LangOptions &LangOpts,
+                             bool Complain) override {
       Out.indent(2) << "Language options:\n";
 #define LANGOPT(Name, Bits, Default, Description) \
       DUMP_BOOLEAN(LangOpts.Name, Description);
@@ -350,14 +441,12 @@ namespace {
       return false;
     }
 
-    virtual bool ReadTargetOptions(const TargetOptions &TargetOpts,
-                                   bool Complain) {
+    bool ReadTargetOptions(const TargetOptions &TargetOpts,
+                           bool Complain) override {
       Out.indent(2) << "Target options:\n";
       Out.indent(4) << "  Triple: " << TargetOpts.Triple << "\n";
       Out.indent(4) << "  CPU: " << TargetOpts.CPU << "\n";
       Out.indent(4) << "  ABI: " << TargetOpts.ABI << "\n";
-      Out.indent(4) << "  C++ ABI: " << TargetOpts.CXXABI << "\n";
-      Out.indent(4) << "  Linker version: " << TargetOpts.LinkerVersion << "\n";
 
       if (!TargetOpts.FeaturesAsWritten.empty()) {
         Out.indent(4) << "Target features:\n";
@@ -370,8 +459,28 @@ namespace {
       return false;
     }
 
-    virtual bool ReadHeaderSearchOptions(const HeaderSearchOptions &HSOpts,
-                                         bool Complain) {
+    virtual bool
+    ReadDiagnosticOptions(IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts,
+                          bool Complain) override {
+      Out.indent(2) << "Diagnostic options:\n";
+#define DIAGOPT(Name, Bits, Default) DUMP_BOOLEAN(DiagOpts->Name, #Name);
+#define ENUM_DIAGOPT(Name, Type, Bits, Default) \
+      Out.indent(4) << #Name << ": " << DiagOpts->get##Name() << "\n";
+#define VALUE_DIAGOPT(Name, Bits, Default) \
+      Out.indent(4) << #Name << ": " << DiagOpts->Name << "\n";
+#include "clang/Basic/DiagnosticOptions.def"
+
+      Out.indent(4) << "Diagnostic flags:\n";
+      for (const std::string &Warning : DiagOpts->Warnings)
+        Out.indent(6) << "-W" << Warning << "\n";
+      for (const std::string &Remark : DiagOpts->Remarks)
+        Out.indent(6) << "-R" << Remark << "\n";
+
+      return false;
+    }
+
+    bool ReadHeaderSearchOptions(const HeaderSearchOptions &HSOpts,
+                                 bool Complain) override {
       Out.indent(2) << "Header search options:\n";
       Out.indent(4) << "System root [-isysroot=]: '" << HSOpts.Sysroot << "'\n";
       DUMP_BOOLEAN(HSOpts.UseBuiltinIncludes,
@@ -385,9 +494,9 @@ namespace {
       return false;
     }
 
-    virtual bool ReadPreprocessorOptions(const PreprocessorOptions &PPOpts,
-                                         bool Complain,
-                                         std::string &SuggestedPredefines) {
+    bool ReadPreprocessorOptions(const PreprocessorOptions &PPOpts,
+                                 bool Complain,
+                                 std::string &SuggestedPredefines) override {
       Out.indent(2) << "Preprocessor options:\n";
       DUMP_BOOLEAN(PPOpts.UsePredefines,
                    "Uses compiler/target-specific predefines [-undef]");
@@ -416,12 +525,12 @@ namespace {
 
 void DumpModuleInfoAction::ExecuteAction() {
   // Set up the output file.
-  llvm::OwningPtr<llvm::raw_fd_ostream> OutFile;
+  std::unique_ptr<llvm::raw_fd_ostream> OutFile;
   StringRef OutputFileName = getCompilerInstance().getFrontendOpts().OutputFile;
   if (!OutputFileName.empty() && OutputFileName != "-") {
     std::string ErrorInfo;
     OutFile.reset(new llvm::raw_fd_ostream(OutputFileName.str().c_str(),
-                                           ErrorInfo));
+                                           ErrorInfo, llvm::sys::fs::F_Text));
   }
   llvm::raw_ostream &Out = OutFile.get()? *OutFile.get() : llvm::outs();
 
@@ -485,7 +594,7 @@ void PreprocessOnlyAction::ExecuteAction() {
   Preprocessor &PP = getCompilerInstance().getPreprocessor();
 
   // Ignore unknown pragmas.
-  PP.AddPragmaHandler(new EmptyPragmaHandler());
+  PP.IgnorePragmas();
 
   Token Tok;
   // Start parsing the specified input file.
diff --git a/lib/Frontend/HeaderIncludeGen.cpp b/lib/Frontend/HeaderIncludeGen.cpp
index 237e5b1ac0c6..a2f5896746af 100644
--- a/lib/Frontend/HeaderIncludeGen.cpp
+++ b/lib/Frontend/HeaderIncludeGen.cpp
@@ -40,23 +40,24 @@ public:
       delete OutputFile;
   }
 
-  virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
-                           SrcMgr::CharacteristicKind FileType,
-                           FileID PrevFID);
+  void FileChanged(SourceLocation Loc, FileChangeReason Reason,
+                   SrcMgr::CharacteristicKind FileType,
+                   FileID PrevFID) override;
 };
 }
 
 void clang::AttachHeaderIncludeGen(Preprocessor &PP, bool ShowAllHeaders,
                                    StringRef OutputPath, bool ShowDepth,
                                    bool MSStyle) {
-  raw_ostream *OutputFile = &llvm::errs();
+  raw_ostream *OutputFile = MSStyle ? &llvm::outs() : &llvm::errs();
   bool OwnsOutputFile = false;
 
   // Open the output file, if used.
   if (!OutputPath.empty()) {
     std::string Error;
     llvm::raw_fd_ostream *OS = new llvm::raw_fd_ostream(
-        OutputPath.str().c_str(), Error, llvm::sys::fs::F_Append);
+        OutputPath.str().c_str(), Error,
+        llvm::sys::fs::F_Append | llvm::sys::fs::F_Text);
     if (!Error.empty()) {
       PP.getDiagnostics().Report(
         clang::diag::warn_fe_cc_print_header_failure) << Error;
@@ -130,5 +131,6 @@ void HeaderIncludesCallback::FileChanged(SourceLocation Loc,
     Msg += '\n';
 
     OutputFile->write(Msg.data(), Msg.size());
+    OutputFile->flush();
   }
 }
diff --git a/lib/Frontend/InitHeaderSearch.cpp b/lib/Frontend/InitHeaderSearch.cpp
index d144cbb8945d..d2edc9479f6b 100644
--- a/lib/Frontend/InitHeaderSearch.cpp
+++ b/lib/Frontend/InitHeaderSearch.cpp
@@ -110,7 +110,7 @@ public:
 }  // end anonymous namespace.
 
 static bool CanPrefixSysroot(StringRef Path) {
-#if defined(_WIN32)
+#if defined(LLVM_ON_WIN32)
   return !Path.empty() && llvm::sys::path::is_separator(Path[0]);
 #else
   return llvm::sys::path::is_absolute(Path);
@@ -268,7 +268,6 @@ void InitHeaderSearch::AddDefaultCIncludePaths(const llvm::Triple &triple,
 
   switch (os) {
   case llvm::Triple::Linux:
-  case llvm::Triple::Win32:
     llvm_unreachable("Include management is handled in the driver.");
 
   case llvm::Triple::Haiku:
@@ -307,10 +306,13 @@ void InitHeaderSearch::AddDefaultCIncludePaths(const llvm::Triple &triple,
     break;
   case llvm::Triple::RTEMS:
     break;
-  case llvm::Triple::Cygwin:
-    AddPath("/usr/include/w32api", System, false);
-    break;
-  case llvm::Triple::MinGW32: { 
+  case llvm::Triple::Win32:
+    switch (triple.getEnvironment()) {
+    default: llvm_unreachable("Include management is handled in the driver.");
+    case llvm::Triple::Cygnus:
+      AddPath("/usr/include/w32api", System, false);
+      break;
+    case llvm::Triple::GNU:
       // mingw-w64 crt include paths
       // <sysroot>/i686-w64-mingw32/include
       SmallString<128> P = StringRef(HSOpts.ResourceDir);
@@ -328,12 +330,12 @@ void InitHeaderSearch::AddDefaultCIncludePaths(const llvm::Triple &triple,
       llvm::sys::path::append(P, "../../../include");
       AddPath(P.str(), System, false);
       AddPath("/mingw/include", System, false);
-#if defined(_WIN32)
+#if defined(LLVM_ON_WIN32)
       AddPath("c:/mingw/include", System, false); 
 #endif
+      break;
     }
     break;
-      
   default:
     break;
   }
@@ -376,58 +378,58 @@ AddDefaultCPlusPlusIncludePaths(const llvm::Triple &triple, const HeaderSearchOp
       AddGnuCPlusPlusIncludePaths("/usr/include/c++/4.2.1",
                                   "arm-apple-darwin10", "v6", "", triple);
       break;
+
+    case llvm::Triple::aarch64:
+    case llvm::Triple::arm64:
+      AddGnuCPlusPlusIncludePaths("/usr/include/c++/4.2.1",
+                                  "arm64-apple-darwin10", "", "", triple);
+      break;
     }
     return;
   }
 
   switch (os) {
   case llvm::Triple::Linux:
-  case llvm::Triple::Win32:
     llvm_unreachable("Include management is handled in the driver.");
 
-  case llvm::Triple::Cygwin:
-    // Cygwin-1.7
-    AddMinGWCPlusPlusIncludePaths("/usr/lib/gcc", "i686-pc-cygwin", "4.7.3");
-    AddMinGWCPlusPlusIncludePaths("/usr/lib/gcc", "i686-pc-cygwin", "4.5.3");
-    AddMinGWCPlusPlusIncludePaths("/usr/lib/gcc", "i686-pc-cygwin", "4.3.4");
-    // g++-4 / Cygwin-1.5
-    AddMinGWCPlusPlusIncludePaths("/usr/lib/gcc", "i686-pc-cygwin", "4.3.2");
-    break;
-  case llvm::Triple::MinGW32:
-    // mingw-w64 C++ include paths (i686-w64-mingw32 and x86_64-w64-mingw32)
-    AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.5.0");
-    AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.5.1");
-    AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.5.2");
-    AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.5.3");
-    AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.5.4");
-    AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.6.0");
-    AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.6.1");
-    AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.6.2");
-    AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.6.3");
-    AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.7.0");
-    // mingw.org C++ include paths
-    AddMinGWCPlusPlusIncludePaths("/mingw/lib/gcc", "mingw32", "4.5.2"); //MSYS
-#if defined(_WIN32)
-    AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.8.1");
-    AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.6.2");
-    AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.6.1");
-    AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.5.2");
-    AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.5.0");
-    AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.4.0");
-    AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.3.0");
+  case llvm::Triple::Win32:
+    switch (triple.getEnvironment()) {
+    default: llvm_unreachable("Include management is handled in the driver.");
+    case llvm::Triple::Cygnus:
+      // Cygwin-1.7
+      AddMinGWCPlusPlusIncludePaths("/usr/lib/gcc", "i686-pc-cygwin", "4.7.3");
+      AddMinGWCPlusPlusIncludePaths("/usr/lib/gcc", "i686-pc-cygwin", "4.5.3");
+      AddMinGWCPlusPlusIncludePaths("/usr/lib/gcc", "i686-pc-cygwin", "4.3.4");
+      // g++-4 / Cygwin-1.5
+      AddMinGWCPlusPlusIncludePaths("/usr/lib/gcc", "i686-pc-cygwin", "4.3.2");
+      break;
+    case llvm::Triple::GNU:
+      // mingw-w64 C++ include paths (i686-w64-mingw32 and x86_64-w64-mingw32)
+      AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.7.0");
+      AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.7.1");
+      AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.7.2");
+      AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.7.3");
+      AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.8.0");
+      AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.8.1");
+      AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.8.2");
+      // mingw.org C++ include paths
+#if defined(LLVM_ON_WIN32)
+      AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.7.0");
+      AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.7.1");
+      AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.7.2");
+      AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.7.3");
+      AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.8.0");
+      AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.8.1");
+      AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.8.2");
 #endif
-    break;
+      break;
+    }
   case llvm::Triple::DragonFly:
     if (llvm::sys::fs::exists("/usr/lib/gcc47"))
       AddPath("/usr/include/c++/4.7", CXXSystem, false);
     else
       AddPath("/usr/include/c++/4.4", CXXSystem, false);
     break;
-  case llvm::Triple::FreeBSD:
-    // FreeBSD 8.0
-    // FreeBSD 7.3
-    AddGnuCPlusPlusIncludePaths("/usr/include/c++/4.2", "", "", "", triple);
-    break;
   case llvm::Triple::OpenBSD: {
     std::string t = triple.getTriple();
     if (t.substr(0, 6) == "x86_64")
@@ -466,8 +468,14 @@ void InitHeaderSearch::AddDefaultIncludePaths(const LangOptions &Lang,
     break; // Everything else continues to use this routine's logic.
 
   case llvm::Triple::Linux:
-  case llvm::Triple::Win32:
     return;
+
+  case llvm::Triple::Win32:
+    if (triple.getEnvironment() == llvm::Triple::MSVC ||
+        triple.getEnvironment() == llvm::Triple::Itanium ||
+        triple.getObjectFormat() == llvm::Triple::MachO)
+      return;
+    break;
   }
 
   if (Lang.CPlusPlus && HSOpts.UseStandardCXXIncludes &&
diff --git a/lib/Frontend/InitPreprocessor.cpp b/lib/Frontend/InitPreprocessor.cpp
index c7d25509e595..7a9d09a5e7ac 100644
--- a/lib/Frontend/InitPreprocessor.cpp
+++ b/lib/Frontend/InitPreprocessor.cpp
@@ -86,7 +86,7 @@ static void AddImplicitIncludePTH(MacroBuilder &Builder, Preprocessor &PP,
                                   StringRef ImplicitIncludePTH) {
   PTHManager *P = PP.getPTHManager();
   // Null check 'P' in the corner case where it couldn't be created.
-  const char *OriginalFile = P ? P->getOriginalSourceFile() : 0;
+  const char *OriginalFile = P ? P->getOriginalSourceFile() : nullptr;
 
   if (!OriginalFile) {
     PP.getDiagnostics().Report(diag::err_fe_pth_file_has_no_source_header)
@@ -180,7 +180,7 @@ static void DefineFloatMacros(MacroBuilder &Builder, StringRef Prefix,
 /// DefineTypeSize - Emit a macro to the predefines buffer that declares a macro
 /// named MacroName with the max value for a type with width 'TypeWidth' a
 /// signedness of 'isSigned' and with a value suffix of 'ValSuffix' (e.g. LL).
-static void DefineTypeSize(StringRef MacroName, unsigned TypeWidth,
+static void DefineTypeSize(const Twine &MacroName, unsigned TypeWidth,
                            StringRef ValSuffix, bool isSigned,
                            MacroBuilder &Builder) {
   llvm::APInt MaxVal = isSigned ? llvm::APInt::getSignedMaxValue(TypeWidth)
@@ -190,12 +190,22 @@ static void DefineTypeSize(StringRef MacroName, unsigned TypeWidth,
 
 /// DefineTypeSize - An overloaded helper that uses TargetInfo to determine
 /// the width, suffix, and signedness of the given type
-static void DefineTypeSize(StringRef MacroName, TargetInfo::IntType Ty,
+static void DefineTypeSize(const Twine &MacroName, TargetInfo::IntType Ty,
                            const TargetInfo &TI, MacroBuilder &Builder) {
   DefineTypeSize(MacroName, TI.getTypeWidth(Ty), TI.getTypeConstantSuffix(Ty), 
                  TI.isTypeSigned(Ty), Builder);
 }
 
+static void DefineFmt(const Twine &Prefix, TargetInfo::IntType Ty,
+                      const TargetInfo &TI, MacroBuilder &Builder) {
+  bool IsSigned = TI.isTypeSigned(Ty);
+  StringRef FmtModifier = TI.getTypeFormatModifier(Ty);
+  for (const char *Fmt = IsSigned ? "di" : "ouxX"; *Fmt; ++Fmt) {
+    Builder.defineMacro(Prefix + "_FMT" + Twine(*Fmt) + "__",
+                        Twine("\"") + FmtModifier + Twine(*Fmt) + "\"");
+  }
+}
+
 static void DefineType(const Twine &MacroName, TargetInfo::IntType Ty,
                        MacroBuilder &Builder) {
   Builder.defineMacro(MacroName, TargetInfo::getTypeName(Ty));
@@ -212,23 +222,70 @@ static void DefineTypeSizeof(StringRef MacroName, unsigned BitWidth,
                       Twine(BitWidth / TI.getCharWidth()));
 }
 
-static void DefineExactWidthIntType(TargetInfo::IntType Ty, 
-                               const TargetInfo &TI, MacroBuilder &Builder) {
+static void DefineExactWidthIntType(TargetInfo::IntType Ty,
+                                    const TargetInfo &TI,
+                                    MacroBuilder &Builder) {
+  int TypeWidth = TI.getTypeWidth(Ty);
+  bool IsSigned = TI.isTypeSigned(Ty);
+
+  // Use the target specified int64 type, when appropriate, so that [u]int64_t
+  // ends up being defined in terms of the correct type.
+  if (TypeWidth == 64)
+    Ty = IsSigned ? TI.getInt64Type() : TI.getUInt64Type();
+
+  const char *Prefix = IsSigned ? "__INT" : "__UINT";
+
+  DefineType(Prefix + Twine(TypeWidth) + "_TYPE__", Ty, Builder);
+  DefineFmt(Prefix + Twine(TypeWidth), Ty, TI, Builder);
+
+  StringRef ConstSuffix(TI.getTypeConstantSuffix(Ty));
+  Builder.defineMacro(Prefix + Twine(TypeWidth) + "_C_SUFFIX__", ConstSuffix);
+}
+
+static void DefineExactWidthIntTypeSize(TargetInfo::IntType Ty,
+                                        const TargetInfo &TI,
+                                        MacroBuilder &Builder) {
   int TypeWidth = TI.getTypeWidth(Ty);
+  bool IsSigned = TI.isTypeSigned(Ty);
 
   // Use the target specified int64 type, when appropriate, so that [u]int64_t
   // ends up being defined in terms of the correct type.
   if (TypeWidth == 64)
-    Ty = TI.getInt64Type();
+    Ty = IsSigned ? TI.getInt64Type() : TI.getUInt64Type();
+
+  const char *Prefix = IsSigned ? "__INT" : "__UINT";
+  DefineTypeSize(Prefix + Twine(TypeWidth) + "_MAX__", Ty, TI, Builder);
+}
+
+static void DefineLeastWidthIntType(unsigned TypeWidth, bool IsSigned,
+                                    const TargetInfo &TI,
+                                    MacroBuilder &Builder) {
+  TargetInfo::IntType Ty = TI.getLeastIntTypeByWidth(TypeWidth, IsSigned);
+  if (Ty == TargetInfo::NoInt)
+    return;
+
+  const char *Prefix = IsSigned ? "__INT_LEAST" : "__UINT_LEAST";
+  DefineType(Prefix + Twine(TypeWidth) + "_TYPE__", Ty, Builder);
+  DefineTypeSize(Prefix + Twine(TypeWidth) + "_MAX__", Ty, TI, Builder);
+  DefineFmt(Prefix + Twine(TypeWidth), Ty, TI, Builder);
+}
+
+static void DefineFastIntType(unsigned TypeWidth, bool IsSigned,
+                              const TargetInfo &TI, MacroBuilder &Builder) {
+  // stdint.h currently defines the fast int types as equivalent to the least
+  // types.
+  TargetInfo::IntType Ty = TI.getLeastIntTypeByWidth(TypeWidth, IsSigned);
+  if (Ty == TargetInfo::NoInt)
+    return;
 
-  DefineType("__INT" + Twine(TypeWidth) + "_TYPE__", Ty, Builder);
+  const char *Prefix = IsSigned ? "__INT_FAST" : "__UINT_FAST";
+  DefineType(Prefix + Twine(TypeWidth) + "_TYPE__", Ty, Builder);
+  DefineTypeSize(Prefix + Twine(TypeWidth) + "_MAX__", Ty, TI, Builder);
 
-  StringRef ConstSuffix(TargetInfo::getTypeConstantSuffix(Ty));
-  if (!ConstSuffix.empty())
-    Builder.defineMacro("__INT" + Twine(TypeWidth) + "_C_SUFFIX__",
-                        ConstSuffix);
+  DefineFmt(Prefix + Twine(TypeWidth), Ty, TI, Builder);
 }
 
+
 /// Get the value the ATOMIC_*_LOCK_FREE macro should have for a type with
 /// the specified properties.
 static const char *getLockFreeValue(unsigned TypeWidth, unsigned TypeAlign,
@@ -300,7 +357,7 @@ static void InitializeStandardPredefinedMacros(const TargetInfo &TI,
                                                const LangOptions &LangOpts,
                                                const FrontendOptions &FEOpts,
                                                MacroBuilder &Builder) {
-  if (!LangOpts.MicrosoftMode && !LangOpts.TraditionalCPP)
+  if (!LangOpts.MSVCCompat && !LangOpts.TraditionalCPP)
     Builder.defineMacro("__STDC__");
   if (LangOpts.Freestanding)
     Builder.defineMacro("__STDC_HOSTED__", "0");
@@ -315,9 +372,14 @@ static void InitializeStandardPredefinedMacros(const TargetInfo &TI,
     else if (!LangOpts.GNUMode && LangOpts.Digraphs)
       Builder.defineMacro("__STDC_VERSION__", "199409L");
   } else {
-    // FIXME: Use the right value for __cplusplus for C++1y once one is chosen.
-    if (LangOpts.CPlusPlus1y)
-      Builder.defineMacro("__cplusplus", "201305L");
+    // FIXME: Use correct value for C++17.
+    if (LangOpts.CPlusPlus1z)
+      Builder.defineMacro("__cplusplus", "201406L");
+    // C++1y [cpp.predefined]p1:
+    //   The name __cplusplus is defined to the value 201402L when compiling a
+    //   C++ translation unit.
+    else if (LangOpts.CPlusPlus1y)
+      Builder.defineMacro("__cplusplus", "201402L");
     // C++11 [cpp.predefined]p1:
     //   The name __cplusplus is defined to the value 201103L when compiling a
     //   C++ translation unit.
@@ -399,7 +461,7 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
                       + getClangFullRepositoryVersion() + "\"");
 #undef TOSTR
 #undef TOSTR2
-  if (!LangOpts.MicrosoftMode) {
+  if (!LangOpts.MSVCCompat) {
     // Currently claim to be compatible with GCC 4.2.1-5621, but only if we're
     // not compiling for MSVC compatibility
     Builder.defineMacro("__GNUC_MINOR__", "2");
@@ -428,10 +490,10 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
   // Initialize language-specific preprocessor defines.
 
   // Standard conforming mode?
-  if (!LangOpts.GNUMode)
+  if (!LangOpts.GNUMode && !LangOpts.MSVCCompat)
     Builder.defineMacro("__STRICT_ANSI__");
 
-  if (LangOpts.CPlusPlus11)
+  if (!LangOpts.MSVCCompat && LangOpts.CPlusPlus11)
     Builder.defineMacro("__GXX_EXPERIMENTAL_CXX0X__");
 
   if (LangOpts.ObjC1) {
@@ -489,9 +551,9 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
     Builder.defineMacro("__BLOCKS__");
   }
 
-  if (LangOpts.CXXExceptions)
+  if (!LangOpts.MSVCCompat && LangOpts.CXXExceptions)
     Builder.defineMacro("__EXCEPTIONS");
-  if (LangOpts.RTTI)
+  if (!LangOpts.MSVCCompat && LangOpts.RTTI)
     Builder.defineMacro("__GXX_RTTI");
   if (LangOpts.SjLjExceptions)
     Builder.defineMacro("__USING_SJLJ_EXCEPTIONS__");
@@ -499,27 +561,18 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
   if (LangOpts.Deprecated)
     Builder.defineMacro("__DEPRECATED");
 
-  if (LangOpts.CPlusPlus) {
+  if (!LangOpts.MSVCCompat && LangOpts.CPlusPlus) {
     Builder.defineMacro("__GNUG__", "4");
     Builder.defineMacro("__GXX_WEAK__");
     Builder.defineMacro("__private_extern__", "extern");
   }
 
   if (LangOpts.MicrosoftExt) {
-    // Both __PRETTY_FUNCTION__ and __FUNCTION__ are GCC extensions, however
-    // VC++ appears to only like __FUNCTION__.
-    Builder.defineMacro("__PRETTY_FUNCTION__", "__FUNCTION__");
-    // Work around some issues with Visual C++ headers.
     if (LangOpts.WChar) {
       // wchar_t supported as a keyword.
       Builder.defineMacro("_WCHAR_T_DEFINED");
       Builder.defineMacro("_NATIVE_WCHAR_T_DEFINED");
     }
-    if (LangOpts.CPlusPlus) {
-      // FIXME: Support Microsoft's __identifier extension in the lexer.
-      Builder.append("#define __identifier(x) x");
-      Builder.append("class type_info;");
-    }
   }
 
   if (LangOpts.Optimize)
@@ -540,11 +593,13 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
   Builder.defineMacro("__ORDER_LITTLE_ENDIAN__", "1234");
   Builder.defineMacro("__ORDER_BIG_ENDIAN__",    "4321");
   Builder.defineMacro("__ORDER_PDP_ENDIAN__",    "3412");
-  if (TI.isBigEndian())
+  if (TI.isBigEndian()) {
     Builder.defineMacro("__BYTE_ORDER__", "__ORDER_BIG_ENDIAN__");
-  else
+    Builder.defineMacro("__BIG_ENDIAN__");
+  } else {
     Builder.defineMacro("__BYTE_ORDER__", "__ORDER_LITTLE_ENDIAN__");
-
+    Builder.defineMacro("__LITTLE_ENDIAN__");
+  }
 
   if (TI.getPointerWidth(0) == 64 && TI.getLongWidth() == 64
       && TI.getIntWidth() == 32) {
@@ -552,6 +607,12 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
     Builder.defineMacro("__LP64__");
   }
 
+  if (TI.getPointerWidth(0) == 32 && TI.getLongWidth() == 32
+      && TI.getIntWidth() == 32) {
+    Builder.defineMacro("_ILP32");
+    Builder.defineMacro("__ILP32__");
+  }
+
   // Define type sizing macros based on the target properties.
   assert(TI.getCharWidth() == 8 && "Only support 8-bit char so far");
   Builder.defineMacro("__CHAR_BIT__", "8");
@@ -565,6 +626,13 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
   DefineTypeSize("__INTMAX_MAX__", TI.getIntMaxType(), TI, Builder);
   DefineTypeSize("__SIZE_MAX__", TI.getSizeType(), TI, Builder);
 
+  if (!LangOpts.MSVCCompat) {
+    DefineTypeSize("__UINTMAX_MAX__", TI.getUIntMaxType(), TI, Builder);
+    DefineTypeSize("__PTRDIFF_MAX__", TI.getPtrDiffType(0), TI, Builder);
+    DefineTypeSize("__INTPTR_MAX__", TI.getIntPtrType(), TI, Builder);
+    DefineTypeSize("__UINTPTR_MAX__", TI.getUIntPtrType(), TI, Builder);
+  }
+
   DefineTypeSizeof("__SIZEOF_DOUBLE__", TI.getDoubleWidth(), TI, Builder);
   DefineTypeSizeof("__SIZEOF_FLOAT__", TI.getFloatWidth(), TI, Builder);
   DefineTypeSizeof("__SIZEOF_INT__", TI.getIntWidth(), TI, Builder);
@@ -585,22 +653,39 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
     DefineTypeSizeof("__SIZEOF_INT128__", 128, TI, Builder);
 
   DefineType("__INTMAX_TYPE__", TI.getIntMaxType(), Builder);
+  DefineFmt("__INTMAX", TI.getIntMaxType(), TI, Builder);
+  Builder.defineMacro("__INTMAX_C_SUFFIX__",
+                      TI.getTypeConstantSuffix(TI.getIntMaxType()));
   DefineType("__UINTMAX_TYPE__", TI.getUIntMaxType(), Builder);
+  DefineFmt("__UINTMAX", TI.getUIntMaxType(), TI, Builder);
+  Builder.defineMacro("__UINTMAX_C_SUFFIX__",
+                      TI.getTypeConstantSuffix(TI.getUIntMaxType()));
   DefineTypeWidth("__INTMAX_WIDTH__",  TI.getIntMaxType(), TI, Builder);
   DefineType("__PTRDIFF_TYPE__", TI.getPtrDiffType(0), Builder);
+  DefineFmt("__PTRDIFF", TI.getPtrDiffType(0), TI, Builder);
   DefineTypeWidth("__PTRDIFF_WIDTH__", TI.getPtrDiffType(0), TI, Builder);
   DefineType("__INTPTR_TYPE__", TI.getIntPtrType(), Builder);
+  DefineFmt("__INTPTR", TI.getIntPtrType(), TI, Builder);
   DefineTypeWidth("__INTPTR_WIDTH__", TI.getIntPtrType(), TI, Builder);
   DefineType("__SIZE_TYPE__", TI.getSizeType(), Builder);
+  DefineFmt("__SIZE", TI.getSizeType(), TI, Builder);
   DefineTypeWidth("__SIZE_WIDTH__", TI.getSizeType(), TI, Builder);
   DefineType("__WCHAR_TYPE__", TI.getWCharType(), Builder);
   DefineTypeWidth("__WCHAR_WIDTH__", TI.getWCharType(), TI, Builder);
   DefineType("__WINT_TYPE__", TI.getWIntType(), Builder);
   DefineTypeWidth("__WINT_WIDTH__", TI.getWIntType(), TI, Builder);
   DefineTypeWidth("__SIG_ATOMIC_WIDTH__", TI.getSigAtomicType(), TI, Builder);
+  DefineTypeSize("__SIG_ATOMIC_MAX__", TI.getSigAtomicType(), TI, Builder);
   DefineType("__CHAR16_TYPE__", TI.getChar16Type(), Builder);
   DefineType("__CHAR32_TYPE__", TI.getChar32Type(), Builder);
 
+  if (!LangOpts.MSVCCompat) {
+    DefineTypeWidth("__UINTMAX_WIDTH__",  TI.getUIntMaxType(), TI, Builder);
+    DefineType("__UINTPTR_TYPE__", TI.getUIntPtrType(), Builder);
+    DefineFmt("__UINTPTR", TI.getUIntPtrType(), TI, Builder);
+    DefineTypeWidth("__UINTPTR_WIDTH__", TI.getUIntPtrType(), TI, Builder);
+  }
+
   DefineFloatMacros(Builder, "FLT", &TI.getFloatFormat(), "F");
   DefineFloatMacros(Builder, "DBL", &TI.getDoubleFormat(), "");
   DefineFloatMacros(Builder, "LDBL", &TI.getLongDoubleFormat(), "L");
@@ -619,8 +704,7 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
     Builder.defineMacro("__WINT_UNSIGNED__");
 
   // Define exact-width integer types for stdint.h
-  Builder.defineMacro("__INT" + Twine(TI.getCharWidth()) + "_TYPE__",
-                      "char");
+  DefineExactWidthIntType(TargetInfo::SignedChar, TI, Builder);
 
   if (TI.getShortWidth() > TI.getCharWidth())
     DefineExactWidthIntType(TargetInfo::SignedShort, TI, Builder);
@@ -634,6 +718,54 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
   if (TI.getLongLongWidth() > TI.getLongWidth())
     DefineExactWidthIntType(TargetInfo::SignedLongLong, TI, Builder);
 
+  if (!LangOpts.MSVCCompat) {
+    DefineExactWidthIntType(TargetInfo::UnsignedChar, TI, Builder);
+    DefineExactWidthIntTypeSize(TargetInfo::UnsignedChar, TI, Builder);
+    DefineExactWidthIntTypeSize(TargetInfo::SignedChar, TI, Builder);
+
+    if (TI.getShortWidth() > TI.getCharWidth()) {
+      DefineExactWidthIntType(TargetInfo::UnsignedShort, TI, Builder);
+      DefineExactWidthIntTypeSize(TargetInfo::UnsignedShort, TI, Builder);
+      DefineExactWidthIntTypeSize(TargetInfo::SignedShort, TI, Builder);
+    }
+
+    if (TI.getIntWidth() > TI.getShortWidth()) {
+      DefineExactWidthIntType(TargetInfo::UnsignedInt, TI, Builder);
+      DefineExactWidthIntTypeSize(TargetInfo::UnsignedInt, TI, Builder);
+      DefineExactWidthIntTypeSize(TargetInfo::SignedInt, TI, Builder);
+    }
+
+    if (TI.getLongWidth() > TI.getIntWidth()) {
+      DefineExactWidthIntType(TargetInfo::UnsignedLong, TI, Builder);
+      DefineExactWidthIntTypeSize(TargetInfo::UnsignedLong, TI, Builder);
+      DefineExactWidthIntTypeSize(TargetInfo::SignedLong, TI, Builder);
+    }
+
+    if (TI.getLongLongWidth() > TI.getLongWidth()) {
+      DefineExactWidthIntType(TargetInfo::UnsignedLongLong, TI, Builder);
+      DefineExactWidthIntTypeSize(TargetInfo::UnsignedLongLong, TI, Builder);
+      DefineExactWidthIntTypeSize(TargetInfo::SignedLongLong, TI, Builder);
+    }
+
+    DefineLeastWidthIntType(8, true, TI, Builder);
+    DefineLeastWidthIntType(8, false, TI, Builder);
+    DefineLeastWidthIntType(16, true, TI, Builder);
+    DefineLeastWidthIntType(16, false, TI, Builder);
+    DefineLeastWidthIntType(32, true, TI, Builder);
+    DefineLeastWidthIntType(32, false, TI, Builder);
+    DefineLeastWidthIntType(64, true, TI, Builder);
+    DefineLeastWidthIntType(64, false, TI, Builder);
+
+    DefineFastIntType(8, true, TI, Builder);
+    DefineFastIntType(8, false, TI, Builder);
+    DefineFastIntType(16, true, TI, Builder);
+    DefineFastIntType(16, false, TI, Builder);
+    DefineFastIntType(32, true, TI, Builder);
+    DefineFastIntType(32, false, TI, Builder);
+    DefineFastIntType(64, true, TI, Builder);
+    DefineFastIntType(64, false, TI, Builder);
+  }
+
   if (const char *Prefix = TI.getUserLabelPrefix())
     Builder.defineMacro("__USER_LABEL_PREFIX__", Prefix);
 
@@ -642,36 +774,38 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
   else
     Builder.defineMacro("__FINITE_MATH_ONLY__", "0");
 
-  if (LangOpts.GNUInline)
-    Builder.defineMacro("__GNUC_GNU_INLINE__");
-  else
-    Builder.defineMacro("__GNUC_STDC_INLINE__");
+  if (!LangOpts.MSVCCompat) {
+    if (LangOpts.GNUInline)
+      Builder.defineMacro("__GNUC_GNU_INLINE__");
+    else
+      Builder.defineMacro("__GNUC_STDC_INLINE__");
 
-  // The value written by __atomic_test_and_set.
-  // FIXME: This is target-dependent.
-  Builder.defineMacro("__GCC_ATOMIC_TEST_AND_SET_TRUEVAL", "1");
+    // The value written by __atomic_test_and_set.
+    // FIXME: This is target-dependent.
+    Builder.defineMacro("__GCC_ATOMIC_TEST_AND_SET_TRUEVAL", "1");
 
-  // Used by libstdc++ to implement ATOMIC_<foo>_LOCK_FREE.
-  unsigned InlineWidthBits = TI.getMaxAtomicInlineWidth();
+    // Used by libstdc++ to implement ATOMIC_<foo>_LOCK_FREE.
+    unsigned InlineWidthBits = TI.getMaxAtomicInlineWidth();
 #define DEFINE_LOCK_FREE_MACRO(TYPE, Type) \
-  Builder.defineMacro("__GCC_ATOMIC_" #TYPE "_LOCK_FREE", \
-                      getLockFreeValue(TI.get##Type##Width(), \
-                                       TI.get##Type##Align(), \
-                                       InlineWidthBits));
-  DEFINE_LOCK_FREE_MACRO(BOOL, Bool);
-  DEFINE_LOCK_FREE_MACRO(CHAR, Char);
-  DEFINE_LOCK_FREE_MACRO(CHAR16_T, Char16);
-  DEFINE_LOCK_FREE_MACRO(CHAR32_T, Char32);
-  DEFINE_LOCK_FREE_MACRO(WCHAR_T, WChar);
-  DEFINE_LOCK_FREE_MACRO(SHORT, Short);
-  DEFINE_LOCK_FREE_MACRO(INT, Int);
-  DEFINE_LOCK_FREE_MACRO(LONG, Long);
-  DEFINE_LOCK_FREE_MACRO(LLONG, LongLong);
-  Builder.defineMacro("__GCC_ATOMIC_POINTER_LOCK_FREE",
-                      getLockFreeValue(TI.getPointerWidth(0),
-                                       TI.getPointerAlign(0),
-                                       InlineWidthBits));
+    Builder.defineMacro("__GCC_ATOMIC_" #TYPE "_LOCK_FREE", \
+                        getLockFreeValue(TI.get##Type##Width(), \
+                                         TI.get##Type##Align(), \
+                                         InlineWidthBits));
+    DEFINE_LOCK_FREE_MACRO(BOOL, Bool);
+    DEFINE_LOCK_FREE_MACRO(CHAR, Char);
+    DEFINE_LOCK_FREE_MACRO(CHAR16_T, Char16);
+    DEFINE_LOCK_FREE_MACRO(CHAR32_T, Char32);
+    DEFINE_LOCK_FREE_MACRO(WCHAR_T, WChar);
+    DEFINE_LOCK_FREE_MACRO(SHORT, Short);
+    DEFINE_LOCK_FREE_MACRO(INT, Int);
+    DEFINE_LOCK_FREE_MACRO(LONG, Long);
+    DEFINE_LOCK_FREE_MACRO(LLONG, LongLong);
+    Builder.defineMacro("__GCC_ATOMIC_POINTER_LOCK_FREE",
+                        getLockFreeValue(TI.getPointerWidth(0),
+                                         TI.getPointerAlign(0),
+                                         InlineWidthBits));
 #undef DEFINE_LOCK_FREE_MACRO
+  }
 
   if (LangOpts.NoInlineDefine)
     Builder.defineMacro("__NO_INLINE__");
@@ -693,8 +827,10 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
 
   if (LangOpts.getStackProtector() == LangOptions::SSPOn)
     Builder.defineMacro("__SSP__");
+  else if (LangOpts.getStackProtector() == LangOptions::SSPStrong)
+    Builder.defineMacro("__SSP_STRONG__", "2");
   else if (LangOpts.getStackProtector() == LangOptions::SSPReq)
-    Builder.defineMacro("__SSP_ALL__", "2");
+    Builder.defineMacro("__SSP_ALL__", "3");
 
   if (FEOpts.ProgramAction == frontend::RewriteObjC)
     Builder.defineMacro("__weak", "__attribute__((objc_gc(weak)))");
@@ -717,86 +853,23 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
 
   // OpenMP definition
   if (LangOpts.OpenMP) {
-    // OpenMP 2.2: 
+    // OpenMP 2.2:
     //   In implementations that support a preprocessor, the _OPENMP
     //   macro name is defined to have the decimal value yyyymm where
     //   yyyy and mm are the year and the month designations of the
     //   version of the OpenMP API that the implementation support.
-    Builder.defineMacro("_OPENMP", "201107");
+    Builder.defineMacro("_OPENMP", "201307");
   }
 
   // Get other target #defines.
   TI.getTargetDefines(LangOpts, Builder);
 }
 
-// Initialize the remapping of files to alternative contents, e.g.,
-// those specified through other files.
-static void InitializeFileRemapping(DiagnosticsEngine &Diags,
-                                    SourceManager &SourceMgr,
-                                    FileManager &FileMgr,
-                                    const PreprocessorOptions &InitOpts) {
-  // Remap files in the source manager (with buffers).
-  for (PreprocessorOptions::const_remapped_file_buffer_iterator
-         Remap = InitOpts.remapped_file_buffer_begin(),
-         RemapEnd = InitOpts.remapped_file_buffer_end();
-       Remap != RemapEnd;
-       ++Remap) {
-    // Create the file entry for the file that we're mapping from.
-    const FileEntry *FromFile = FileMgr.getVirtualFile(Remap->first,
-                                                Remap->second->getBufferSize(),
-                                                       0);
-    if (!FromFile) {
-      Diags.Report(diag::err_fe_remap_missing_from_file)
-        << Remap->first;
-      if (!InitOpts.RetainRemappedFileBuffers)
-        delete Remap->second;
-      continue;
-    }
-
-    // Override the contents of the "from" file with the contents of
-    // the "to" file.
-    SourceMgr.overrideFileContents(FromFile, Remap->second,
-                                   InitOpts.RetainRemappedFileBuffers);
-  }
-
-  // Remap files in the source manager (with other files).
-  for (PreprocessorOptions::const_remapped_file_iterator
-         Remap = InitOpts.remapped_file_begin(),
-         RemapEnd = InitOpts.remapped_file_end();
-       Remap != RemapEnd;
-       ++Remap) {
-    // Find the file that we're mapping to.
-    const FileEntry *ToFile = FileMgr.getFile(Remap->second);
-    if (!ToFile) {
-      Diags.Report(diag::err_fe_remap_missing_to_file)
-      << Remap->first << Remap->second;
-      continue;
-    }
-    
-    // Create the file entry for the file that we're mapping from.
-    const FileEntry *FromFile = FileMgr.getVirtualFile(Remap->first,
-                                                       ToFile->getSize(), 0);
-    if (!FromFile) {
-      Diags.Report(diag::err_fe_remap_missing_from_file)
-      << Remap->first;
-      continue;
-    }
-    
-    // Override the contents of the "from" file with the contents of
-    // the "to" file.
-    SourceMgr.overrideFileContents(FromFile, ToFile);
-  }
-
-  SourceMgr.setOverridenFilesKeepOriginalName(
-                                        InitOpts.RemappedFilesKeepOriginalName);
-}
-
 /// InitializePreprocessor - Initialize the preprocessor getting it and the
 /// environment ready to process a single file. This returns true on error.
 ///
 void clang::InitializePreprocessor(Preprocessor &PP,
                                    const PreprocessorOptions &InitOpts,
-                                   const HeaderSearchOptions &HSOpts,
                                    const FrontendOptions &FEOpts) {
   const LangOptions &LangOpts = PP.getLangOpts();
   std::string PredefineBuffer;
@@ -804,9 +877,6 @@ void clang::InitializePreprocessor(Preprocessor &PP,
   llvm::raw_string_ostream Predefines(PredefineBuffer);
   MacroBuilder Builder(Predefines);
 
-  InitializeFileRemapping(PP.getDiagnostics(), PP.getSourceManager(),
-                          PP.getFileManager(), InitOpts);
-
   // Emit line markers for various builtin sections of the file.  We don't do
   // this in asm preprocessor mode, because "# 4" is not a line marker directive
   // in this mode.
@@ -880,9 +950,4 @@ void clang::InitializePreprocessor(Preprocessor &PP,
                           
   // Copy PredefinedBuffer into the Preprocessor.
   PP.setPredefines(Predefines.str());
-  
-  // Initialize the header search object.
-  ApplyHeaderSearchOptions(PP.getHeaderSearchInfo(), HSOpts,
-                           PP.getLangOpts(),
-                           PP.getTargetInfo().getTriple());
 }
diff --git a/lib/Frontend/LangStandards.cpp b/lib/Frontend/LangStandards.cpp
index f86a574c30ab..f133327f4298 100644
--- a/lib/Frontend/LangStandards.cpp
+++ b/lib/Frontend/LangStandards.cpp
@@ -35,7 +35,7 @@ const LangStandard *LangStandard::getLangStandardForName(StringRef Name) {
 #include "clang/Frontend/LangStandards.def"
     .Default(lang_unspecified);
   if (K == lang_unspecified)
-    return 0;
+    return nullptr;
 
   return &getLangStandardForKind(K);
 }
diff --git a/lib/Frontend/LogDiagnosticPrinter.cpp b/lib/Frontend/LogDiagnosticPrinter.cpp
index 2189b8658ed2..19539e0a5eb2 100644
--- a/lib/Frontend/LogDiagnosticPrinter.cpp
+++ b/lib/Frontend/LogDiagnosticPrinter.cpp
@@ -10,16 +10,18 @@
 #include "clang/Frontend/LogDiagnosticPrinter.h"
 #include "clang/Basic/DiagnosticOptions.h"
 #include "clang/Basic/FileManager.h"
+#include "clang/Basic/PlistSupport.h"
 #include "clang/Basic/SourceManager.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
 using namespace clang;
+using namespace markup;
 
 LogDiagnosticPrinter::LogDiagnosticPrinter(raw_ostream &os,
                                            DiagnosticOptions *diags,
                                            bool _OwnsOutputStream)
-  : OS(os), LangOpts(0), DiagOpts(diags),
+  : OS(os), LangOpts(nullptr), DiagOpts(diags),
     OwnsOutputStream(_OwnsOutputStream) {
 }
 
@@ -31,6 +33,7 @@ LogDiagnosticPrinter::~LogDiagnosticPrinter() {
 static StringRef getLevelName(DiagnosticsEngine::Level Level) {
   switch (Level) {
   case DiagnosticsEngine::Ignored: return "ignored";
+  case DiagnosticsEngine::Remark:  return "remark";
   case DiagnosticsEngine::Note:    return "note";
   case DiagnosticsEngine::Warning: return "warning";
   case DiagnosticsEngine::Error:   return "error";
@@ -39,19 +42,34 @@ static StringRef getLevelName(DiagnosticsEngine::Level Level) {
   llvm_unreachable("Invalid DiagnosticsEngine level!");
 }
 
-// Escape XML characters inside the raw string.
-static void emitString(llvm::raw_svector_ostream &OS, const StringRef Raw) {
-  for (StringRef::iterator I = Raw.begin(), E = Raw.end(); I != E; ++I) {
-    char c = *I;
-    switch (c) {
-    default:   OS << c; break;
-    case '&':  OS << "&amp;"; break;
-    case '<':  OS << "&lt;"; break;
-    case '>':  OS << "&gt;"; break;
-    case '\'': OS << "&apos;"; break;
-    case '\"': OS << "&quot;"; break;
-    }
+void
+LogDiagnosticPrinter::EmitDiagEntry(llvm::raw_ostream &OS,
+                                    const LogDiagnosticPrinter::DiagEntry &DE) {
+  OS << "    <dict>\n";
+  OS << "      <key>level</key>\n"
+     << "      ";
+  EmitString(OS, getLevelName(DE.DiagnosticLevel)) << '\n';
+  if (!DE.Filename.empty()) {
+    OS << "      <key>filename</key>\n"
+       << "      ";
+    EmitString(OS, DE.Filename) << '\n';
+  }
+  if (DE.Line != 0) {
+    OS << "      <key>line</key>\n"
+       << "      ";
+    EmitInteger(OS, DE.Line) << '\n';
+  }
+  if (DE.Column != 0) {
+    OS << "      <key>column</key>\n"
+       << "      ";
+    EmitInteger(OS, DE.Column) << '\n';
   }
+  if (!DE.Message.empty()) {
+    OS << "      <key>message</key>\n"
+       << "      ";
+    EmitString(OS, DE.Message) << '\n';
+  }
+  OS << "    </dict>\n";
 }
 
 void LogDiagnosticPrinter::EndSourceFile() {
@@ -71,48 +89,18 @@ void LogDiagnosticPrinter::EndSourceFile() {
   OS << "<dict>\n";
   if (!MainFilename.empty()) {
     OS << "  <key>main-file</key>\n"
-       << "  <string>";
-    emitString(OS, MainFilename);
-    OS << "</string>\n";
+       << "  ";
+    EmitString(OS, MainFilename) << '\n';
   }
   if (!DwarfDebugFlags.empty()) {
     OS << "  <key>dwarf-debug-flags</key>\n"
-       << "  <string>";
-    emitString(OS, DwarfDebugFlags);
-    OS << "</string>\n";
+       << "  ";
+    EmitString(OS, DwarfDebugFlags) << '\n';
   }
   OS << "  <key>diagnostics</key>\n";
   OS << "  <array>\n";
-  for (unsigned i = 0, e = Entries.size(); i != e; ++i) {
-    DiagEntry &DE = Entries[i];
-
-    OS << "    <dict>\n";
-    OS << "      <key>level</key>\n"
-       << "      <string>";
-    emitString(OS, getLevelName(DE.DiagnosticLevel));
-    OS << "</string>\n";
-    if (!DE.Filename.empty()) {
-      OS << "      <key>filename</key>\n"
-         << "      <string>";
-      emitString(OS, DE.Filename);
-      OS << "</string>\n";
-    }
-    if (DE.Line != 0) {
-      OS << "      <key>line</key>\n"
-         << "      <integer>" << DE.Line << "</integer>\n";
-    }
-    if (DE.Column != 0) {
-      OS << "      <key>column</key>\n"
-         << "      <integer>" << DE.Column << "</integer>\n";
-    }
-    if (!DE.Message.empty()) {
-      OS << "      <key>message</key>\n"
-         << "      <string>";
-      emitString(OS, DE.Message);
-      OS << "</string>\n";
-    }
-    OS << "    </dict>\n";
-  }
+  for (auto &DE : Entries)
+    EmitDiagEntry(OS, DE);
   OS << "  </array>\n";
   OS << "</dict>\n";
 
@@ -130,7 +118,7 @@ void LogDiagnosticPrinter::HandleDiagnostic(DiagnosticsEngine::Level Level,
     FileID FID = SM.getMainFileID();
     if (!FID.isInvalid()) {
       const FileEntry *FE = SM.getFileEntryForID(FID);
-      if (FE && FE->getName())
+      if (FE && FE->isValid())
         MainFilename = FE->getName();
     }
   }
@@ -157,7 +145,7 @@ void LogDiagnosticPrinter::HandleDiagnostic(DiagnosticsEngine::Level Level,
       FileID FID = SM.getFileID(Info.getLocation());
       if (!FID.isInvalid()) {
         const FileEntry *FE = SM.getFileEntryForID(FID);
-        if (FE && FE->getName())
+        if (FE && FE->isValid())
           DE.Filename = FE->getName();
       }
     } else {
diff --git a/lib/Frontend/Makefile b/lib/Frontend/Makefile
index 3c13ad69cc67..8554b7649fa2 100644
--- a/lib/Frontend/Makefile
+++ b/lib/Frontend/Makefile
@@ -8,7 +8,7 @@
 ##===----------------------------------------------------------------------===##
 
 CLANG_LEVEL := ../..
+DIRS := Rewrite
 LIBRARYNAME := clangFrontend
 
 include $(CLANG_LEVEL)/Makefile
-
diff --git a/lib/Frontend/ModuleDependencyCollector.cpp b/lib/Frontend/ModuleDependencyCollector.cpp
new file mode 100644
index 000000000000..d30f9214f82e
--- /dev/null
+++ b/lib/Frontend/ModuleDependencyCollector.cpp
@@ -0,0 +1,116 @@
+//===--- ModuleDependencyCollector.cpp - Collect module dependencies ------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Collect the dependencies of a set of modules.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Frontend/Utils.h"
+#include "clang/Serialization/ASTReader.h"
+#include "llvm/ADT/iterator_range.h"
+#include "llvm/ADT/StringSet.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace clang;
+
+namespace {
+/// Private implementation for ModuleDependencyCollector
+class ModuleDependencyListener : public ASTReaderListener {
+  ModuleDependencyCollector &Collector;
+
+  std::error_code copyToRoot(StringRef Src);
+public:
+  ModuleDependencyListener(ModuleDependencyCollector &Collector)
+      : Collector(Collector) {}
+  bool needsInputFileVisitation() override { return true; }
+  bool needsSystemInputFileVisitation() override { return true; }
+  bool visitInputFile(StringRef Filename, bool IsSystem,
+                      bool IsOverridden) override;
+};
+}
+
+void ModuleDependencyCollector::attachToASTReader(ASTReader &R) {
+  R.addListener(new ModuleDependencyListener(*this));
+}
+
+void ModuleDependencyCollector::writeFileMap() {
+  if (Seen.empty())
+    return;
+
+  SmallString<256> Dest = getDest();
+  llvm::sys::path::append(Dest, "vfs.yaml");
+
+  std::string ErrorInfo;
+  llvm::raw_fd_ostream OS(Dest.c_str(), ErrorInfo, llvm::sys::fs::F_Text);
+  if (!ErrorInfo.empty()) {
+    setHasErrors();
+    return;
+  }
+  VFSWriter.write(OS);
+}
+
+/// Remove traversal (ie, . or ..) from the given absolute path.
+static void removePathTraversal(SmallVectorImpl<char> &Path) {
+  using namespace llvm::sys;
+  SmallVector<StringRef, 16> ComponentStack;
+  StringRef P(Path.data(), Path.size());
+
+  // Skip the root path, then look for traversal in the components.
+  StringRef Rel = path::relative_path(P);
+  for (StringRef C : llvm::make_range(path::begin(Rel), path::end(Rel))) {
+    if (C == ".")
+      continue;
+    if (C == "..") {
+      assert(ComponentStack.size() && "Path traverses out of parent");
+      ComponentStack.pop_back();
+    } else
+      ComponentStack.push_back(C);
+  }
+
+  // The stack is now the path without any directory traversal.
+  SmallString<256> Buffer = path::root_path(P);
+  for (StringRef C : ComponentStack)
+    path::append(Buffer, C);
+
+  // Put the result in Path.
+  Path.swap(Buffer);
+}
+
+std::error_code ModuleDependencyListener::copyToRoot(StringRef Src) {
+  using namespace llvm::sys;
+
+  // We need an absolute path to append to the root.
+  SmallString<256> AbsoluteSrc = Src;
+  fs::make_absolute(AbsoluteSrc);
+  removePathTraversal(AbsoluteSrc);
+
+  // Build the destination path.
+  SmallString<256> Dest = Collector.getDest();
+  path::append(Dest, path::relative_path(AbsoluteSrc));
+
+  // Copy the file into place.
+  if (std::error_code EC = fs::create_directories(path::parent_path(Dest),
+                                                   /*IgnoreExisting=*/true))
+    return EC;
+  if (std::error_code EC = fs::copy_file(AbsoluteSrc.str(), Dest.str()))
+    return EC;
+  // Use the absolute path under the root for the file mapping.
+  Collector.addFileMapping(AbsoluteSrc.str(), Dest.str());
+  return std::error_code();
+}
+
+bool ModuleDependencyListener::visitInputFile(StringRef Filename, bool IsSystem,
+                                              bool IsOverridden) {
+  if (Collector.insertSeen(Filename))
+    if (copyToRoot(Filename))
+      Collector.setHasErrors();
+  return true;
+}
diff --git a/lib/Frontend/MultiplexConsumer.cpp b/lib/Frontend/MultiplexConsumer.cpp
index 9cf68a5e9b25..0e933a3f165f 100644
--- a/lib/Frontend/MultiplexConsumer.cpp
+++ b/lib/Frontend/MultiplexConsumer.cpp
@@ -30,14 +30,14 @@ public:
   // Does NOT take ownership of the elements in L.
   MultiplexASTDeserializationListener(
       const std::vector<ASTDeserializationListener*>& L);
-  virtual void ReaderInitialized(ASTReader *Reader);
-  virtual void IdentifierRead(serialization::IdentID ID,
-                              IdentifierInfo *II);
-  virtual void TypeRead(serialization::TypeIdx Idx, QualType T);
-  virtual void DeclRead(serialization::DeclID ID, const Decl *D);
-  virtual void SelectorRead(serialization::SelectorID iD, Selector Sel);
-  virtual void MacroDefinitionRead(serialization::PreprocessedEntityID, 
-                                   MacroDefinition *MD);
+  void ReaderInitialized(ASTReader *Reader) override;
+  void IdentifierRead(serialization::IdentID ID,
+                      IdentifierInfo *II) override;
+  void TypeRead(serialization::TypeIdx Idx, QualType T) override;
+  void DeclRead(serialization::DeclID ID, const Decl *D) override;
+  void SelectorRead(serialization::SelectorID iD, Selector Sel) override;
+  void MacroDefinitionRead(serialization::PreprocessedEntityID,
+                           MacroDefinition *MD) override;
 private:
   std::vector<ASTDeserializationListener*> Listeners;
 };
@@ -89,25 +89,24 @@ class MultiplexASTMutationListener : public ASTMutationListener {
 public:
   // Does NOT take ownership of the elements in L.
   MultiplexASTMutationListener(ArrayRef<ASTMutationListener*> L);
-  virtual void CompletedTagDefinition(const TagDecl *D);
-  virtual void AddedVisibleDecl(const DeclContext *DC, const Decl *D);
-  virtual void AddedCXXImplicitMember(const CXXRecordDecl *RD, const Decl *D);
-  virtual void AddedCXXTemplateSpecialization(const ClassTemplateDecl *TD,
-                                    const ClassTemplateSpecializationDecl *D);
-  virtual void
-  AddedCXXTemplateSpecialization(const VarTemplateDecl *TD,
-                                 const VarTemplateSpecializationDecl *D);
-  virtual void AddedCXXTemplateSpecialization(const FunctionTemplateDecl *TD,
-                                              const FunctionDecl *D);
-  virtual void DeducedReturnType(const FunctionDecl *FD, QualType ReturnType);
-  virtual void CompletedImplicitDefinition(const FunctionDecl *D);
-  virtual void StaticDataMemberInstantiated(const VarDecl *D);
-  virtual void AddedObjCCategoryToInterface(const ObjCCategoryDecl *CatD,
-                                            const ObjCInterfaceDecl *IFD);
-  virtual void AddedObjCPropertyInClassExtension(const ObjCPropertyDecl *Prop,
-                                            const ObjCPropertyDecl *OrigProp,
-                                            const ObjCCategoryDecl *ClassExt);
-  void DeclarationMarkedUsed(const Decl *D) LLVM_OVERRIDE;
+  void CompletedTagDefinition(const TagDecl *D) override;
+  void AddedVisibleDecl(const DeclContext *DC, const Decl *D) override;
+  void AddedCXXImplicitMember(const CXXRecordDecl *RD, const Decl *D) override;
+  void AddedCXXTemplateSpecialization(const ClassTemplateDecl *TD,
+                            const ClassTemplateSpecializationDecl *D) override;
+  void AddedCXXTemplateSpecialization(const VarTemplateDecl *TD,
+                               const VarTemplateSpecializationDecl *D) override;
+  void AddedCXXTemplateSpecialization(const FunctionTemplateDecl *TD,
+                                      const FunctionDecl *D) override;
+  void DeducedReturnType(const FunctionDecl *FD, QualType ReturnType) override;
+  void CompletedImplicitDefinition(const FunctionDecl *D) override;
+  void StaticDataMemberInstantiated(const VarDecl *D) override;
+  void AddedObjCCategoryToInterface(const ObjCCategoryDecl *CatD,
+                                    const ObjCInterfaceDecl *IFD) override;
+  void AddedObjCPropertyInClassExtension(const ObjCPropertyDecl *Prop,
+                                    const ObjCPropertyDecl *OrigProp,
+                                    const ObjCCategoryDecl *ClassExt) override;
+  void DeclarationMarkedUsed(const Decl *D) override;
 
 private:
   std::vector<ASTMutationListener*> Listeners;
@@ -184,10 +183,9 @@ void MultiplexASTMutationListener::DeclarationMarkedUsed(const Decl *D) {
 
 }  // end namespace clang
 
-
-MultiplexConsumer::MultiplexConsumer(ArrayRef<ASTConsumer*> C)
-    : Consumers(C.begin(), C.end()),
-      MutationListener(0), DeserializationListener(0) {
+MultiplexConsumer::MultiplexConsumer(ArrayRef<ASTConsumer *> C)
+    : Consumers(C.begin(), C.end()), MutationListener(),
+      DeserializationListener() {
   // Collect the mutation listeners and deserialization listeners of all
   // children, and create a multiplex listener each if so.
   std::vector<ASTMutationListener*> mutationListeners;
@@ -228,6 +226,11 @@ bool MultiplexConsumer::HandleTopLevelDecl(DeclGroupRef D) {
   return Continue;
 }
 
+void MultiplexConsumer::HandleInlineMethodDefinition(CXXMethodDecl *D) {
+  for (size_t i = 0, e = Consumers.size(); i != e; ++i)
+    Consumers[i]->HandleInlineMethodDefinition(D);
+}
+
 void  MultiplexConsumer::HandleCXXStaticMemberVarInstantiation(VarDecl *VD) {
   for (size_t i = 0, e = Consumers.size(); i != e; ++i)
     Consumers[i]->HandleCXXStaticMemberVarInstantiation(VD);
@@ -248,6 +251,11 @@ void MultiplexConsumer::HandleTagDeclDefinition(TagDecl *D) {
     Consumers[i]->HandleTagDeclDefinition(D);
 }
 
+void MultiplexConsumer::HandleTagDeclRequiredDefinition(const TagDecl *D) {
+  for (size_t i = 0, e = Consumers.size(); i != e; ++i)
+    Consumers[i]->HandleTagDeclRequiredDefinition(D);
+}
+
 void MultiplexConsumer::HandleCXXImplicitFunctionInstantiation(FunctionDecl *D){
   for (size_t i = 0, e = Consumers.size(); i != e; ++i)
     Consumers[i]->HandleCXXImplicitFunctionInstantiation(D);
@@ -258,6 +266,26 @@ void MultiplexConsumer::HandleTopLevelDeclInObjCContainer(DeclGroupRef D) {
     Consumers[i]->HandleTopLevelDeclInObjCContainer(D);
 }
 
+void MultiplexConsumer::HandleImplicitImportDecl(ImportDecl *D) {
+  for (size_t i = 0, e = Consumers.size(); i != e; ++i)
+    Consumers[i]->HandleImplicitImportDecl(D);
+}
+
+void MultiplexConsumer::HandleLinkerOptionPragma(llvm::StringRef Opts) {
+  for (size_t i = 0, e = Consumers.size(); i != e; ++i)
+    Consumers[i]->HandleLinkerOptionPragma(Opts);
+}
+
+void MultiplexConsumer::HandleDetectMismatch(llvm::StringRef Name, llvm::StringRef Value) {
+  for (size_t i = 0, e = Consumers.size(); i != e; ++i)
+    Consumers[i]->HandleDetectMismatch(Name, Value);
+}
+
+void MultiplexConsumer::HandleDependentLibrary(llvm::StringRef Lib) {
+  for (size_t i = 0, e = Consumers.size(); i != e; ++i)
+    Consumers[i]->HandleDependentLibrary(Lib);
+}
+
 void MultiplexConsumer::CompleteTentativeDefinition(VarDecl *D) {
   for (size_t i = 0, e = Consumers.size(); i != e; ++i)
     Consumers[i]->CompleteTentativeDefinition(D);
diff --git a/lib/Frontend/PrintPreprocessedOutput.cpp b/lib/Frontend/PrintPreprocessedOutput.cpp
index 55a66d87f8bf..4a6f8dbef928 100644
--- a/lib/Frontend/PrintPreprocessedOutput.cpp
+++ b/lib/Frontend/PrintPreprocessedOutput.cpp
@@ -123,39 +123,27 @@ public:
   }
 
   bool startNewLineIfNeeded(bool ShouldUpdateCurrentLine = true);
-  
-  virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
-                           SrcMgr::CharacteristicKind FileType,
-                           FileID PrevFID);
-  virtual void InclusionDirective(SourceLocation HashLoc,
-                                  const Token &IncludeTok,
-                                  StringRef FileName,
-                                  bool IsAngled,
-                                  CharSourceRange FilenameRange,
-                                  const FileEntry *File,
-                                  StringRef SearchPath,
-                                  StringRef RelativePath,
-                                  const Module *Imported);
-  virtual void Ident(SourceLocation Loc, const std::string &str);
-  virtual void PragmaCaptured(SourceLocation Loc, StringRef Str);
-  virtual void PragmaComment(SourceLocation Loc, const IdentifierInfo *Kind,
-                             const std::string &Str);
-  virtual void PragmaDetectMismatch(SourceLocation Loc,
-                                    const std::string &Name,
-                                    const std::string &Value);
-  virtual void PragmaMessage(SourceLocation Loc, StringRef Namespace,
-                             PragmaMessageKind Kind, StringRef Str);
-  virtual void PragmaDebug(SourceLocation Loc, StringRef DebugType);
-  virtual void PragmaDiagnosticPush(SourceLocation Loc,
-                                    StringRef Namespace);
-  virtual void PragmaDiagnosticPop(SourceLocation Loc,
-                                   StringRef Namespace);
-  virtual void PragmaDiagnostic(SourceLocation Loc, StringRef Namespace,
-                                diag::Mapping Map, StringRef Str);
-  virtual void PragmaWarning(SourceLocation Loc, StringRef WarningSpec,
-                             ArrayRef<int> Ids);
-  virtual void PragmaWarningPush(SourceLocation Loc, int Level);
-  virtual void PragmaWarningPop(SourceLocation Loc);
+
+  void FileChanged(SourceLocation Loc, FileChangeReason Reason,
+                   SrcMgr::CharacteristicKind FileType,
+                   FileID PrevFID) override;
+  void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
+                          StringRef FileName, bool IsAngled,
+                          CharSourceRange FilenameRange, const FileEntry *File,
+                          StringRef SearchPath, StringRef RelativePath,
+                          const Module *Imported) override;
+  void Ident(SourceLocation Loc, const std::string &str) override;
+  void PragmaMessage(SourceLocation Loc, StringRef Namespace,
+                     PragmaMessageKind Kind, StringRef Str) override;
+  void PragmaDebug(SourceLocation Loc, StringRef DebugType) override;
+  void PragmaDiagnosticPush(SourceLocation Loc, StringRef Namespace) override;
+  void PragmaDiagnosticPop(SourceLocation Loc, StringRef Namespace) override;
+  void PragmaDiagnostic(SourceLocation Loc, StringRef Namespace,
+                        diag::Severity Map, StringRef Str) override;
+  void PragmaWarning(SourceLocation Loc, StringRef WarningSpec,
+                     ArrayRef<int> Ids) override;
+  void PragmaWarningPush(SourceLocation Loc, int Level) override;
+  void PragmaWarningPop(SourceLocation Loc) override;
 
   bool HandleFirstTokOnLine(Token &Tok);
 
@@ -174,15 +162,18 @@ public:
                    const Token &Tok) {
     return ConcatInfo.AvoidConcat(PrevPrevTok, PrevTok, Tok);
   }
-  void WriteLineInfo(unsigned LineNo, const char *Extra=0, unsigned ExtraLen=0);
+  void WriteLineInfo(unsigned LineNo, const char *Extra=nullptr,
+                     unsigned ExtraLen=0);
   bool LineMarkersAreDisabled() const { return DisableLineMarkers; }
   void HandleNewlinesInToken(const char *TokStr, unsigned Len);
 
   /// MacroDefined - This hook is called whenever a macro definition is seen.
-  void MacroDefined(const Token &MacroNameTok, const MacroDirective *MD);
+  void MacroDefined(const Token &MacroNameTok,
+                    const MacroDirective *MD) override;
 
   /// MacroUndefined - This hook is called whenever a macro #undef is seen.
-  void MacroUndefined(const Token &MacroNameTok, const MacroDirective *MD);
+  void MacroUndefined(const Token &MacroNameTok,
+                      const MacroDirective *MD) override;
 };
 }  // end anonymous namespace
 
@@ -230,7 +221,7 @@ bool PrintPPOutputPPCallbacks::MoveToLine(unsigned LineNo) {
     }
   } else if (!DisableLineMarkers) {
     // Emit a #line or line marker.
-    WriteLineInfo(LineNo, 0, 0);
+    WriteLineInfo(LineNo, nullptr, 0);
   } else {
     // Okay, we're in -P mode, which turns off line markers.  However, we still
     // need to emit a newline between tokens on different lines.
@@ -355,15 +346,6 @@ void PrintPPOutputPPCallbacks::Ident(SourceLocation Loc, const std::string &S) {
   EmittedTokensOnThisLine = true;
 }
 
-void PrintPPOutputPPCallbacks::PragmaCaptured(SourceLocation Loc,
-                                              StringRef Str) {
-  startNewLineIfNeeded();
-  MoveToLine(Loc);
-  OS << "#pragma captured";
-
-  setEmittedDirectiveOnThisLine();
-}
-
 /// MacroDefined - This hook is called whenever a macro definition is seen.
 void PrintPPOutputPPCallbacks::MacroDefined(const Token &MacroNameTok,
                                             const MacroDirective *MD) {
@@ -402,36 +384,6 @@ static void outputPrintable(llvm::raw_ostream& OS,
     }
 }
 
-void PrintPPOutputPPCallbacks::PragmaComment(SourceLocation Loc,
-                                             const IdentifierInfo *Kind,
-                                             const std::string &Str) {
-  startNewLineIfNeeded();
-  MoveToLine(Loc);
-  OS << "#pragma comment(" << Kind->getName();
-
-  if (!Str.empty()) {
-    OS << ", \"";
-    outputPrintable(OS, Str);
-    OS << '"';
-  }
-
-  OS << ')';
-  setEmittedDirectiveOnThisLine();
-}
-
-void PrintPPOutputPPCallbacks::PragmaDetectMismatch(SourceLocation Loc,
-                                                    const std::string &Name,
-                                                    const std::string &Value) {
-  startNewLineIfNeeded();
-  MoveToLine(Loc);
-  OS << "#pragma detect_mismatch(\"" << Name << '"';
-  outputPrintable(OS, Name);
-  OS << "\", \"";
-  outputPrintable(OS, Value);
-  OS << "\")";
-  setEmittedDirectiveOnThisLine();
-}
-
 void PrintPPOutputPPCallbacks::PragmaMessage(SourceLocation Loc,
                                              StringRef Namespace,
                                              PragmaMessageKind Kind,
@@ -487,23 +439,27 @@ PragmaDiagnosticPop(SourceLocation Loc, StringRef Namespace) {
   setEmittedDirectiveOnThisLine();
 }
 
-void PrintPPOutputPPCallbacks::
-PragmaDiagnostic(SourceLocation Loc, StringRef Namespace,
-                 diag::Mapping Map, StringRef Str) {
+void PrintPPOutputPPCallbacks::PragmaDiagnostic(SourceLocation Loc,
+                                                StringRef Namespace,
+                                                diag::Severity Map,
+                                                StringRef Str) {
   startNewLineIfNeeded();
   MoveToLine(Loc);
   OS << "#pragma " << Namespace << " diagnostic ";
   switch (Map) {
-  case diag::MAP_WARNING:
+  case diag::Severity::Remark:
+    OS << "remark";
+    break;
+  case diag::Severity::Warning:
     OS << "warning";
     break;
-  case diag::MAP_ERROR:
+  case diag::Severity::Error:
     OS << "error";
     break;
-  case diag::MAP_IGNORE:
+  case diag::Severity::Ignored:
     OS << "ignored";
     break;
-  case diag::MAP_FATAL:
+  case diag::Severity::Fatal:
     OS << "fatal";
     break;
   }
@@ -556,6 +512,13 @@ bool PrintPPOutputPPCallbacks::HandleFirstTokOnLine(Token &Tok) {
   // indented for easy reading.
   unsigned ColNo = SM.getExpansionColumnNumber(Tok.getLocation());
 
+  // The first token on a line can have a column number of 1, yet still expect
+  // leading white space, if a macro expansion in column 1 starts with an empty
+  // macro argument, or an empty nested macro expansion. In this case, move the
+  // token to column 2.
+  if (ColNo == 1 && Tok.hasLeadingSpace())
+    ColNo = 2;
+
   // This hack prevents stuff like:
   // #define HASH #
   // HASH define foo bar
@@ -602,8 +565,8 @@ struct UnknownPragmaHandler : public PragmaHandler {
 
   UnknownPragmaHandler(const char *prefix, PrintPPOutputPPCallbacks *callbacks)
     : Prefix(prefix), Callbacks(callbacks) {}
-  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
-                            Token &PragmaTok) {
+  void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                    Token &PragmaTok) override {
     // Figure out what line we went to and insert the appropriate number of
     // newline characters.
     Callbacks->startNewLineIfNeeded();
@@ -615,7 +578,13 @@ struct UnknownPragmaHandler : public PragmaHandler {
         Callbacks->OS << ' ';
       std::string TokSpell = PP.getSpelling(PragmaTok);
       Callbacks->OS.write(&TokSpell[0], TokSpell.size());
-      PP.LexUnexpandedToken(PragmaTok);
+
+      // Expand macros in pragmas with -fms-extensions.  The assumption is that
+      // the majority of pragmas in such a file will be Microsoft pragmas.
+      if (PP.getLangOpts().MicrosoftExt)
+        PP.Lex(PragmaTok);
+      else
+        PP.LexUnexpandedToken(PragmaTok);
     }
     Callbacks->setEmittedDirectiveOnThisLine();
   }
@@ -657,7 +626,9 @@ static void PrintPreprocessedTokens(Preprocessor &PP, Token &Tok,
       // -traditional-cpp the lexer keeps /all/ whitespace, including comments.
       SourceLocation StartLoc = Tok.getLocation();
       Callbacks->MoveToLine(StartLoc.getLocWithOffset(Tok.getLength()));
-    } else if (Tok.is(tok::annot_module_include)) {
+    } else if (Tok.is(tok::annot_module_include) ||
+               Tok.is(tok::annot_module_begin) ||
+               Tok.is(tok::annot_module_end)) {
       // PrintPPOutputPPCallbacks::InclusionDirective handles producing
       // appropriate output here. Ignore this token entirely.
       PP.Lex(Tok);
@@ -702,7 +673,7 @@ static int MacroIDCompare(const id_macro_pair *LHS, const id_macro_pair *RHS) {
 
 static void DoPrintMacros(Preprocessor &PP, raw_ostream *OS) {
   // Ignore unknown pragmas.
-  PP.AddPragmaHandler(new EmptyPragmaHandler());
+  PP.IgnorePragmas();
 
   // -dM mode just scans and ignores all tokens in the files, then dumps out
   // the macro table at the end.
diff --git a/lib/Frontend/Rewrite/CMakeLists.txt b/lib/Frontend/Rewrite/CMakeLists.txt
new file mode 100644
index 000000000000..924bf5d5ee28
--- /dev/null
+++ b/lib/Frontend/Rewrite/CMakeLists.txt
@@ -0,0 +1,22 @@
+set(LLVM_LINK_COMPONENTS
+  Support
+  )
+
+add_clang_library(clangRewriteFrontend
+  FixItRewriter.cpp
+  FrontendActions.cpp
+  HTMLPrint.cpp
+  InclusionRewriter.cpp
+  RewriteMacros.cpp
+  RewriteModernObjC.cpp
+  RewriteObjC.cpp
+  RewriteTest.cpp
+
+  LINK_LIBS
+  clangAST
+  clangBasic
+  clangEdit
+  clangFrontend
+  clangLex
+  clangRewrite
+  )
diff --git a/lib/Frontend/Rewrite/FixItRewriter.cpp b/lib/Frontend/Rewrite/FixItRewriter.cpp
new file mode 100644
index 000000000000..8b7af7166c8f
--- /dev/null
+++ b/lib/Frontend/Rewrite/FixItRewriter.cpp
@@ -0,0 +1,200 @@
+//===--- FixItRewriter.cpp - Fix-It Rewriter Diagnostic Client --*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This is a diagnostic client adaptor that performs rewrites as
+// suggested by code modification hints attached to diagnostics. It
+// then forwards any diagnostics to the adapted diagnostic client.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Rewrite/Frontend/FixItRewriter.h"
+#include "clang/Basic/FileManager.h"
+#include "clang/Basic/SourceLocation.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Edit/Commit.h"
+#include "clang/Edit/EditsReceiver.h"
+#include "clang/Frontend/FrontendDiagnostic.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cstdio>
+#include <memory>
+
+using namespace clang;
+
+FixItRewriter::FixItRewriter(DiagnosticsEngine &Diags, SourceManager &SourceMgr,
+                             const LangOptions &LangOpts,
+                             FixItOptions *FixItOpts)
+  : Diags(Diags),
+    Editor(SourceMgr, LangOpts),
+    Rewrite(SourceMgr, LangOpts),
+    FixItOpts(FixItOpts),
+    NumFailures(0),
+    PrevDiagSilenced(false) {
+  OwnsClient = Diags.ownsClient();
+  Client = Diags.takeClient();
+  Diags.setClient(this);
+}
+
+FixItRewriter::~FixItRewriter() {
+  Diags.takeClient();
+  Diags.setClient(Client, OwnsClient);
+}
+
+bool FixItRewriter::WriteFixedFile(FileID ID, raw_ostream &OS) {
+  const RewriteBuffer *RewriteBuf = Rewrite.getRewriteBufferFor(ID);
+  if (!RewriteBuf) return true;
+  RewriteBuf->write(OS);
+  OS.flush();
+  return false;
+}
+
+namespace {
+
+class RewritesReceiver : public edit::EditsReceiver {
+  Rewriter &Rewrite;
+
+public:
+  RewritesReceiver(Rewriter &Rewrite) : Rewrite(Rewrite) { }
+
+  void insert(SourceLocation loc, StringRef text) override {
+    Rewrite.InsertText(loc, text);
+  }
+  void replace(CharSourceRange range, StringRef text) override {
+    Rewrite.ReplaceText(range.getBegin(), Rewrite.getRangeSize(range), text);
+  }
+};
+
+}
+
+bool FixItRewriter::WriteFixedFiles(
+            std::vector<std::pair<std::string, std::string> > *RewrittenFiles) {
+  if (NumFailures > 0 && !FixItOpts->FixWhatYouCan) {
+    Diag(FullSourceLoc(), diag::warn_fixit_no_changes);
+    return true;
+  }
+
+  RewritesReceiver Rec(Rewrite);
+  Editor.applyRewrites(Rec);
+
+  for (iterator I = buffer_begin(), E = buffer_end(); I != E; ++I) {
+    const FileEntry *Entry = Rewrite.getSourceMgr().getFileEntryForID(I->first);
+    int fd;
+    std::string Filename = FixItOpts->RewriteFilename(Entry->getName(), fd);
+    std::string Err;
+    std::unique_ptr<llvm::raw_fd_ostream> OS;
+    if (fd != -1) {
+      OS.reset(new llvm::raw_fd_ostream(fd, /*shouldClose=*/true));
+    } else {
+      OS.reset(new llvm::raw_fd_ostream(Filename.c_str(), Err,
+                                        llvm::sys::fs::F_None));
+    }
+    if (!Err.empty()) {
+      Diags.Report(clang::diag::err_fe_unable_to_open_output)
+          << Filename << Err;
+      continue;
+    }
+    RewriteBuffer &RewriteBuf = I->second;
+    RewriteBuf.write(*OS);
+    OS->flush();
+
+    if (RewrittenFiles)
+      RewrittenFiles->push_back(std::make_pair(Entry->getName(), Filename));
+  }
+
+  return false;
+}
+
+bool FixItRewriter::IncludeInDiagnosticCounts() const {
+  return Client ? Client->IncludeInDiagnosticCounts() : true;
+}
+
+void FixItRewriter::HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
+                                     const Diagnostic &Info) {
+  // Default implementation (Warnings/errors count).
+  DiagnosticConsumer::HandleDiagnostic(DiagLevel, Info);
+
+  if (!FixItOpts->Silent ||
+      DiagLevel >= DiagnosticsEngine::Error ||
+      (DiagLevel == DiagnosticsEngine::Note && !PrevDiagSilenced) ||
+      (DiagLevel > DiagnosticsEngine::Note && Info.getNumFixItHints())) {
+    Client->HandleDiagnostic(DiagLevel, Info);
+    PrevDiagSilenced = false;
+  } else {
+    PrevDiagSilenced = true;
+  }
+
+  // Skip over any diagnostics that are ignored or notes.
+  if (DiagLevel <= DiagnosticsEngine::Note)
+    return;
+  // Skip over errors if we are only fixing warnings.
+  if (DiagLevel >= DiagnosticsEngine::Error && FixItOpts->FixOnlyWarnings) {
+    ++NumFailures;
+    return;
+  }
+
+  // Make sure that we can perform all of the modifications we
+  // in this diagnostic.
+  edit::Commit commit(Editor);
+  for (unsigned Idx = 0, Last = Info.getNumFixItHints();
+       Idx < Last; ++Idx) {
+    const FixItHint &Hint = Info.getFixItHint(Idx);
+
+    if (Hint.CodeToInsert.empty()) {
+      if (Hint.InsertFromRange.isValid())
+        commit.insertFromRange(Hint.RemoveRange.getBegin(),
+                           Hint.InsertFromRange, /*afterToken=*/false,
+                           Hint.BeforePreviousInsertions);
+      else
+        commit.remove(Hint.RemoveRange);
+    } else {
+      if (Hint.RemoveRange.isTokenRange() ||
+          Hint.RemoveRange.getBegin() != Hint.RemoveRange.getEnd())
+        commit.replace(Hint.RemoveRange, Hint.CodeToInsert);
+      else
+        commit.insert(Hint.RemoveRange.getBegin(), Hint.CodeToInsert,
+                    /*afterToken=*/false, Hint.BeforePreviousInsertions);
+    }
+  }
+  bool CanRewrite = Info.getNumFixItHints() > 0 && commit.isCommitable();
+
+  if (!CanRewrite) {
+    if (Info.getNumFixItHints() > 0)
+      Diag(Info.getLocation(), diag::note_fixit_in_macro);
+
+    // If this was an error, refuse to perform any rewriting.
+    if (DiagLevel >= DiagnosticsEngine::Error) {
+      if (++NumFailures == 1)
+        Diag(Info.getLocation(), diag::note_fixit_unfixed_error);
+    }
+    return;
+  }
+  
+  if (!Editor.commit(commit)) {
+    ++NumFailures;
+    Diag(Info.getLocation(), diag::note_fixit_failed);
+    return;
+  }
+
+  Diag(Info.getLocation(), diag::note_fixit_applied);
+}
+
+/// \brief Emit a diagnostic via the adapted diagnostic client.
+void FixItRewriter::Diag(SourceLocation Loc, unsigned DiagID) {
+  // When producing this diagnostic, we temporarily bypass ourselves,
+  // clear out any current diagnostic, and let the downstream client
+  // format the diagnostic.
+  Diags.takeClient();
+  Diags.setClient(Client);
+  Diags.Clear();
+  Diags.Report(Loc, DiagID);
+  Diags.takeClient();
+  Diags.setClient(this);
+}
+
+FixItOptions::~FixItOptions() {}
diff --git a/lib/Frontend/Rewrite/FrontendActions.cpp b/lib/Frontend/Rewrite/FrontendActions.cpp
new file mode 100644
index 000000000000..59fef736f16a
--- /dev/null
+++ b/lib/Frontend/Rewrite/FrontendActions.cpp
@@ -0,0 +1,196 @@
+//===--- FrontendActions.cpp ----------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Rewrite/Frontend/FrontendActions.h"
+#include "clang/AST/ASTConsumer.h"
+#include "clang/Basic/FileManager.h"
+#include "clang/Frontend/CompilerInstance.h"
+#include "clang/Frontend/FrontendActions.h"
+#include "clang/Frontend/FrontendDiagnostic.h"
+#include "clang/Frontend/Utils.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Parse/Parser.h"
+#include "clang/Rewrite/Frontend/ASTConsumers.h"
+#include "clang/Rewrite/Frontend/FixItRewriter.h"
+#include "clang/Rewrite/Frontend/Rewriters.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/raw_ostream.h"
+#include <memory>
+
+using namespace clang;
+
+//===----------------------------------------------------------------------===//
+// AST Consumer Actions
+//===----------------------------------------------------------------------===//
+
+ASTConsumer *HTMLPrintAction::CreateASTConsumer(CompilerInstance &CI,
+                                                StringRef InFile) {
+  if (raw_ostream *OS = CI.createDefaultOutputFile(false, InFile))
+    return CreateHTMLPrinter(OS, CI.getPreprocessor());
+  return nullptr;
+}
+
+FixItAction::FixItAction() {}
+FixItAction::~FixItAction() {}
+
+ASTConsumer *FixItAction::CreateASTConsumer(CompilerInstance &CI,
+                                            StringRef InFile) {
+  return new ASTConsumer();
+}
+
+namespace {
+class FixItRewriteInPlace : public FixItOptions {
+public:
+  std::string RewriteFilename(const std::string &Filename, int &fd) override {
+    fd = -1;
+    return Filename;
+  }
+};
+
+class FixItActionSuffixInserter : public FixItOptions {
+  std::string NewSuffix;
+
+public:
+  FixItActionSuffixInserter(std::string NewSuffix, bool FixWhatYouCan)
+    : NewSuffix(NewSuffix) {
+      this->FixWhatYouCan = FixWhatYouCan;
+  }
+
+  std::string RewriteFilename(const std::string &Filename, int &fd) override {
+    fd = -1;
+    SmallString<128> Path(Filename);
+    llvm::sys::path::replace_extension(Path,
+      NewSuffix + llvm::sys::path::extension(Path));
+    return Path.str();
+  }
+};
+
+class FixItRewriteToTemp : public FixItOptions {
+public:
+  std::string RewriteFilename(const std::string &Filename, int &fd) override {
+    SmallString<128> Path;
+    llvm::sys::fs::createTemporaryFile(llvm::sys::path::filename(Filename),
+                                       llvm::sys::path::extension(Filename), fd,
+                                       Path);
+    return Path.str();
+  }
+};
+} // end anonymous namespace
+
+bool FixItAction::BeginSourceFileAction(CompilerInstance &CI,
+                                        StringRef Filename) {
+  const FrontendOptions &FEOpts = getCompilerInstance().getFrontendOpts();
+  if (!FEOpts.FixItSuffix.empty()) {
+    FixItOpts.reset(new FixItActionSuffixInserter(FEOpts.FixItSuffix,
+                                                  FEOpts.FixWhatYouCan));
+  } else {
+    FixItOpts.reset(new FixItRewriteInPlace);
+    FixItOpts->FixWhatYouCan = FEOpts.FixWhatYouCan;
+  }
+  Rewriter.reset(new FixItRewriter(CI.getDiagnostics(), CI.getSourceManager(),
+                                   CI.getLangOpts(), FixItOpts.get()));
+  return true;
+}
+
+void FixItAction::EndSourceFileAction() {
+  // Otherwise rewrite all files.
+  Rewriter->WriteFixedFiles();
+}
+
+bool FixItRecompile::BeginInvocation(CompilerInstance &CI) {
+
+  std::vector<std::pair<std::string, std::string> > RewrittenFiles;
+  bool err = false;
+  {
+    const FrontendOptions &FEOpts = CI.getFrontendOpts();
+    std::unique_ptr<FrontendAction> FixAction(new SyntaxOnlyAction());
+    if (FixAction->BeginSourceFile(CI, FEOpts.Inputs[0])) {
+      std::unique_ptr<FixItOptions> FixItOpts;
+      if (FEOpts.FixToTemporaries)
+        FixItOpts.reset(new FixItRewriteToTemp());
+      else
+        FixItOpts.reset(new FixItRewriteInPlace());
+      FixItOpts->Silent = true;
+      FixItOpts->FixWhatYouCan = FEOpts.FixWhatYouCan;
+      FixItOpts->FixOnlyWarnings = FEOpts.FixOnlyWarnings;
+      FixItRewriter Rewriter(CI.getDiagnostics(), CI.getSourceManager(),
+                             CI.getLangOpts(), FixItOpts.get());
+      FixAction->Execute();
+  
+      err = Rewriter.WriteFixedFiles(&RewrittenFiles);
+    
+      FixAction->EndSourceFile();
+      CI.setSourceManager(nullptr);
+      CI.setFileManager(nullptr);
+    } else {
+      err = true;
+    }
+  }
+  if (err)
+    return false;
+  CI.getDiagnosticClient().clear();
+  CI.getDiagnostics().Reset();
+
+  PreprocessorOptions &PPOpts = CI.getPreprocessorOpts();
+  PPOpts.RemappedFiles.insert(PPOpts.RemappedFiles.end(),
+                              RewrittenFiles.begin(), RewrittenFiles.end());
+  PPOpts.RemappedFilesKeepOriginalName = false;
+
+  return true;
+}
+
+#ifdef CLANG_ENABLE_OBJC_REWRITER
+
+ASTConsumer *RewriteObjCAction::CreateASTConsumer(CompilerInstance &CI,
+                                                  StringRef InFile) {
+  if (raw_ostream *OS = CI.createDefaultOutputFile(false, InFile, "cpp")) {
+    if (CI.getLangOpts().ObjCRuntime.isNonFragile())
+      return CreateModernObjCRewriter(InFile, OS,
+                                CI.getDiagnostics(), CI.getLangOpts(),
+                                CI.getDiagnosticOpts().NoRewriteMacros,
+                                (CI.getCodeGenOpts().getDebugInfo() !=
+                                 CodeGenOptions::NoDebugInfo));
+    return CreateObjCRewriter(InFile, OS,
+                              CI.getDiagnostics(), CI.getLangOpts(),
+                              CI.getDiagnosticOpts().NoRewriteMacros);
+  }
+  return nullptr;
+}
+
+#endif
+
+//===----------------------------------------------------------------------===//
+// Preprocessor Actions
+//===----------------------------------------------------------------------===//
+
+void RewriteMacrosAction::ExecuteAction() {
+  CompilerInstance &CI = getCompilerInstance();
+  raw_ostream *OS = CI.createDefaultOutputFile(true, getCurrentFile());
+  if (!OS) return;
+
+  RewriteMacrosInInput(CI.getPreprocessor(), OS);
+}
+
+void RewriteTestAction::ExecuteAction() {
+  CompilerInstance &CI = getCompilerInstance();
+  raw_ostream *OS = CI.createDefaultOutputFile(false, getCurrentFile());
+  if (!OS) return;
+
+  DoRewriteTest(CI.getPreprocessor(), OS);
+}
+
+void RewriteIncludesAction::ExecuteAction() {
+  CompilerInstance &CI = getCompilerInstance();
+  raw_ostream *OS = CI.createDefaultOutputFile(true, getCurrentFile());
+  if (!OS) return;
+
+  RewriteIncludesInInput(CI.getPreprocessor(), OS,
+                         CI.getPreprocessorOutputOpts());
+}
diff --git a/lib/Frontend/Rewrite/HTMLPrint.cpp b/lib/Frontend/Rewrite/HTMLPrint.cpp
new file mode 100644
index 000000000000..64da05fdde61
--- /dev/null
+++ b/lib/Frontend/Rewrite/HTMLPrint.cpp
@@ -0,0 +1,94 @@
+//===--- HTMLPrint.cpp - Source code -> HTML pretty-printing --------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Pretty-printing of source code to HTML.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Rewrite/Frontend/ASTConsumers.h"
+#include "clang/AST/ASTConsumer.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Decl.h"
+#include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/FileManager.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Rewrite/Core/HTMLRewrite.h"
+#include "clang/Rewrite/Core/Rewriter.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace clang;
+
+//===----------------------------------------------------------------------===//
+// Functional HTML pretty-printing.
+//===----------------------------------------------------------------------===//
+
+namespace {
+  class HTMLPrinter : public ASTConsumer {
+    Rewriter R;
+    raw_ostream *Out;
+    Preprocessor &PP;
+    bool SyntaxHighlight, HighlightMacros;
+
+  public:
+    HTMLPrinter(raw_ostream *OS, Preprocessor &pp,
+                bool _SyntaxHighlight, bool _HighlightMacros)
+      : Out(OS), PP(pp), SyntaxHighlight(_SyntaxHighlight),
+        HighlightMacros(_HighlightMacros) {}
+
+    void Initialize(ASTContext &context) override;
+    void HandleTranslationUnit(ASTContext &Ctx) override;
+  };
+}
+
+ASTConsumer* clang::CreateHTMLPrinter(raw_ostream *OS,
+                                      Preprocessor &PP,
+                                      bool SyntaxHighlight,
+                                      bool HighlightMacros) {
+  return new HTMLPrinter(OS, PP, SyntaxHighlight, HighlightMacros);
+}
+
+void HTMLPrinter::Initialize(ASTContext &context) {
+  R.setSourceMgr(context.getSourceManager(), context.getLangOpts());
+}
+
+void HTMLPrinter::HandleTranslationUnit(ASTContext &Ctx) {
+  if (PP.getDiagnostics().hasErrorOccurred())
+    return;
+
+  // Format the file.
+  FileID FID = R.getSourceMgr().getMainFileID();
+  const FileEntry* Entry = R.getSourceMgr().getFileEntryForID(FID);
+  const char* Name;
+  // In some cases, in particular the case where the input is from stdin,
+  // there is no entry.  Fall back to the memory buffer for a name in those
+  // cases.
+  if (Entry)
+    Name = Entry->getName();
+  else
+    Name = R.getSourceMgr().getBuffer(FID)->getBufferIdentifier();
+
+  html::AddLineNumbers(R, FID);
+  html::AddHeaderFooterInternalBuiltinCSS(R, FID, Name);
+
+  // If we have a preprocessor, relex the file and syntax highlight.
+  // We might not have a preprocessor if we come from a deserialized AST file,
+  // for example.
+
+  if (SyntaxHighlight) html::SyntaxHighlight(R, FID, PP);
+  if (HighlightMacros) html::HighlightMacros(R, FID, PP);
+  html::EscapeText(R, FID, false, true);
+
+  // Emit the HTML.
+  const RewriteBuffer &RewriteBuf = R.getEditBuffer(FID);
+  char *Buffer = (char*)malloc(RewriteBuf.size());
+  std::copy(RewriteBuf.begin(), RewriteBuf.end(), Buffer);
+  Out->write(Buffer, RewriteBuf.size());
+  free(Buffer);
+}
diff --git a/lib/Frontend/Rewrite/InclusionRewriter.cpp b/lib/Frontend/Rewrite/InclusionRewriter.cpp
new file mode 100644
index 000000000000..aa7017baee26
--- /dev/null
+++ b/lib/Frontend/Rewrite/InclusionRewriter.cpp
@@ -0,0 +1,547 @@
+//===--- InclusionRewriter.cpp - Rewrite includes into their expansions ---===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This code rewrites include invocations into their expansions.  This gives you
+// a file with all included files merged into it.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Rewrite/Frontend/Rewriters.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Frontend/PreprocessorOutputOptions.h"
+#include "clang/Lex/HeaderSearch.h"
+#include "clang/Lex/Pragma.h"
+#include "clang/Lex/Preprocessor.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace clang;
+using namespace llvm;
+
+namespace {
+
+class InclusionRewriter : public PPCallbacks {
+  /// Information about which #includes were actually performed,
+  /// created by preprocessor callbacks.
+  struct FileChange {
+    const Module *Mod;
+    SourceLocation From;
+    FileID Id;
+    SrcMgr::CharacteristicKind FileType;
+    FileChange(SourceLocation From, const Module *Mod) : Mod(Mod), From(From) {
+    }
+  };
+  Preprocessor &PP; ///< Used to find inclusion directives.
+  SourceManager &SM; ///< Used to read and manage source files.
+  raw_ostream &OS; ///< The destination stream for rewritten contents.
+  const llvm::MemoryBuffer *PredefinesBuffer; ///< The preprocessor predefines.
+  bool ShowLineMarkers; ///< Show #line markers.
+  bool UseLineDirective; ///< Use of line directives or line markers.
+  typedef std::map<unsigned, FileChange> FileChangeMap;
+  FileChangeMap FileChanges; ///< Tracks which files were included where.
+  /// Used transitively for building up the FileChanges mapping over the
+  /// various \c PPCallbacks callbacks.
+  FileChangeMap::iterator LastInsertedFileChange;
+public:
+  InclusionRewriter(Preprocessor &PP, raw_ostream &OS, bool ShowLineMarkers);
+  bool Process(FileID FileId, SrcMgr::CharacteristicKind FileType);
+  void setPredefinesBuffer(const llvm::MemoryBuffer *Buf) {
+    PredefinesBuffer = Buf;
+  }
+private:
+  void FileChanged(SourceLocation Loc, FileChangeReason Reason,
+                   SrcMgr::CharacteristicKind FileType,
+                   FileID PrevFID) override;
+  void FileSkipped(const FileEntry &ParentFile, const Token &FilenameTok,
+                   SrcMgr::CharacteristicKind FileType) override;
+  void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
+                          StringRef FileName, bool IsAngled,
+                          CharSourceRange FilenameRange, const FileEntry *File,
+                          StringRef SearchPath, StringRef RelativePath,
+                          const Module *Imported) override;
+  void WriteLineInfo(const char *Filename, int Line,
+                     SrcMgr::CharacteristicKind FileType,
+                     StringRef EOL, StringRef Extra = StringRef());
+  void WriteImplicitModuleImport(const Module *Mod, StringRef EOL);
+  void OutputContentUpTo(const MemoryBuffer &FromFile,
+                         unsigned &WriteFrom, unsigned WriteTo,
+                         StringRef EOL, int &lines,
+                         bool EnsureNewline);
+  void CommentOutDirective(Lexer &DirectivesLex, const Token &StartToken,
+                           const MemoryBuffer &FromFile, StringRef EOL,
+                           unsigned &NextToWrite, int &Lines);
+  bool HandleHasInclude(FileID FileId, Lexer &RawLex,
+                        const DirectoryLookup *Lookup, Token &Tok,
+                        bool &FileExists);
+  const FileChange *FindFileChangeLocation(SourceLocation Loc) const;
+  StringRef NextIdentifierName(Lexer &RawLex, Token &RawToken);
+};
+
+}  // end anonymous namespace
+
+/// Initializes an InclusionRewriter with a \p PP source and \p OS destination.
+InclusionRewriter::InclusionRewriter(Preprocessor &PP, raw_ostream &OS,
+                                     bool ShowLineMarkers)
+  : PP(PP), SM(PP.getSourceManager()), OS(OS), PredefinesBuffer(nullptr),
+    ShowLineMarkers(ShowLineMarkers),
+    LastInsertedFileChange(FileChanges.end()) {
+  // If we're in microsoft mode, use normal #line instead of line markers.
+  UseLineDirective = PP.getLangOpts().MicrosoftExt;
+}
+
+/// Write appropriate line information as either #line directives or GNU line
+/// markers depending on what mode we're in, including the \p Filename and
+/// \p Line we are located at, using the specified \p EOL line separator, and
+/// any \p Extra context specifiers in GNU line directives.
+void InclusionRewriter::WriteLineInfo(const char *Filename, int Line,
+                                      SrcMgr::CharacteristicKind FileType,
+                                      StringRef EOL, StringRef Extra) {
+  if (!ShowLineMarkers)
+    return;
+  if (UseLineDirective) {
+    OS << "#line" << ' ' << Line << ' ' << '"';
+    OS.write_escaped(Filename);
+    OS << '"';
+  } else {
+    // Use GNU linemarkers as described here:
+    // http://gcc.gnu.org/onlinedocs/cpp/Preprocessor-Output.html
+    OS << '#' << ' ' << Line << ' ' << '"';
+    OS.write_escaped(Filename);
+    OS << '"';
+    if (!Extra.empty())
+      OS << Extra;
+    if (FileType == SrcMgr::C_System)
+      // "`3' This indicates that the following text comes from a system header
+      // file, so certain warnings should be suppressed."
+      OS << " 3";
+    else if (FileType == SrcMgr::C_ExternCSystem)
+      // as above for `3', plus "`4' This indicates that the following text
+      // should be treated as being wrapped in an implicit extern "C" block."
+      OS << " 3 4";
+  }
+  OS << EOL;
+}
+
+void InclusionRewriter::WriteImplicitModuleImport(const Module *Mod,
+                                                  StringRef EOL) {
+  OS << "@import " << Mod->getFullModuleName() << ";"
+     << " /* clang -frewrite-includes: implicit import */" << EOL;
+}
+
+/// FileChanged - Whenever the preprocessor enters or exits a #include file
+/// it invokes this handler.
+void InclusionRewriter::FileChanged(SourceLocation Loc,
+                                    FileChangeReason Reason,
+                                    SrcMgr::CharacteristicKind NewFileType,
+                                    FileID) {
+  if (Reason != EnterFile)
+    return;
+  if (LastInsertedFileChange == FileChanges.end())
+    // we didn't reach this file (eg: the main file) via an inclusion directive
+    return;
+  LastInsertedFileChange->second.Id = FullSourceLoc(Loc, SM).getFileID();
+  LastInsertedFileChange->second.FileType = NewFileType;
+  LastInsertedFileChange = FileChanges.end();
+}
+
+/// Called whenever an inclusion is skipped due to canonical header protection
+/// macros.
+void InclusionRewriter::FileSkipped(const FileEntry &/*ParentFile*/,
+                                    const Token &/*FilenameTok*/,
+                                    SrcMgr::CharacteristicKind /*FileType*/) {
+  assert(LastInsertedFileChange != FileChanges.end() && "A file, that wasn't "
+    "found via an inclusion directive, was skipped");
+  FileChanges.erase(LastInsertedFileChange);
+  LastInsertedFileChange = FileChanges.end();
+}
+
+/// This should be called whenever the preprocessor encounters include
+/// directives. It does not say whether the file has been included, but it
+/// provides more information about the directive (hash location instead
+/// of location inside the included file). It is assumed that the matching
+/// FileChanged() or FileSkipped() is called after this.
+void InclusionRewriter::InclusionDirective(SourceLocation HashLoc,
+                                           const Token &/*IncludeTok*/,
+                                           StringRef /*FileName*/,
+                                           bool /*IsAngled*/,
+                                           CharSourceRange /*FilenameRange*/,
+                                           const FileEntry * /*File*/,
+                                           StringRef /*SearchPath*/,
+                                           StringRef /*RelativePath*/,
+                                           const Module *Imported) {
+  assert(LastInsertedFileChange == FileChanges.end() && "Another inclusion "
+    "directive was found before the previous one was processed");
+  std::pair<FileChangeMap::iterator, bool> p = FileChanges.insert(
+    std::make_pair(HashLoc.getRawEncoding(), FileChange(HashLoc, Imported)));
+  assert(p.second && "Unexpected revisitation of the same include directive");
+  if (!Imported)
+    LastInsertedFileChange = p.first;
+}
+
+/// Simple lookup for a SourceLocation (specifically one denoting the hash in
+/// an inclusion directive) in the map of inclusion information, FileChanges.
+const InclusionRewriter::FileChange *
+InclusionRewriter::FindFileChangeLocation(SourceLocation Loc) const {
+  FileChangeMap::const_iterator I = FileChanges.find(Loc.getRawEncoding());
+  if (I != FileChanges.end())
+    return &I->second;
+  return nullptr;
+}
+
+/// Detect the likely line ending style of \p FromFile by examining the first
+/// newline found within it.
+static StringRef DetectEOL(const MemoryBuffer &FromFile) {
+  // detect what line endings the file uses, so that added content does not mix
+  // the style
+  const char *Pos = strchr(FromFile.getBufferStart(), '\n');
+  if (!Pos)
+    return "\n";
+  if (Pos + 1 < FromFile.getBufferEnd() && Pos[1] == '\r')
+    return "\n\r";
+  if (Pos - 1 >= FromFile.getBufferStart() && Pos[-1] == '\r')
+    return "\r\n";
+  return "\n";
+}
+
+/// Writes out bytes from \p FromFile, starting at \p NextToWrite and ending at
+/// \p WriteTo - 1.
+void InclusionRewriter::OutputContentUpTo(const MemoryBuffer &FromFile,
+                                          unsigned &WriteFrom, unsigned WriteTo,
+                                          StringRef EOL, int &Line,
+                                          bool EnsureNewline) {
+  if (WriteTo <= WriteFrom)
+    return;
+  if (&FromFile == PredefinesBuffer) {
+    // Ignore the #defines of the predefines buffer.
+    WriteFrom = WriteTo;
+    return;
+  }
+  OS.write(FromFile.getBufferStart() + WriteFrom, WriteTo - WriteFrom);
+  // count lines manually, it's faster than getPresumedLoc()
+  Line += std::count(FromFile.getBufferStart() + WriteFrom,
+                     FromFile.getBufferStart() + WriteTo, '\n');
+  if (EnsureNewline) {
+    char LastChar = FromFile.getBufferStart()[WriteTo - 1];
+    if (LastChar != '\n' && LastChar != '\r')
+      OS << EOL;
+  }
+  WriteFrom = WriteTo;
+}
+
+/// Print characters from \p FromFile starting at \p NextToWrite up until the
+/// inclusion directive at \p StartToken, then print out the inclusion
+/// inclusion directive disabled by a #if directive, updating \p NextToWrite
+/// and \p Line to track the number of source lines visited and the progress
+/// through the \p FromFile buffer.
+void InclusionRewriter::CommentOutDirective(Lexer &DirectiveLex,
+                                            const Token &StartToken,
+                                            const MemoryBuffer &FromFile,
+                                            StringRef EOL,
+                                            unsigned &NextToWrite, int &Line) {
+  OutputContentUpTo(FromFile, NextToWrite,
+    SM.getFileOffset(StartToken.getLocation()), EOL, Line, false);
+  Token DirectiveToken;
+  do {
+    DirectiveLex.LexFromRawLexer(DirectiveToken);
+  } while (!DirectiveToken.is(tok::eod) && DirectiveToken.isNot(tok::eof));
+  if (&FromFile == PredefinesBuffer) {
+    // OutputContentUpTo() would not output anything anyway.
+    return;
+  }
+  OS << "#if 0 /* expanded by -frewrite-includes */" << EOL;
+  OutputContentUpTo(FromFile, NextToWrite,
+    SM.getFileOffset(DirectiveToken.getLocation()) + DirectiveToken.getLength(),
+    EOL, Line, true);
+  OS << "#endif /* expanded by -frewrite-includes */" << EOL;
+}
+
+/// Find the next identifier in the pragma directive specified by \p RawToken.
+StringRef InclusionRewriter::NextIdentifierName(Lexer &RawLex,
+                                                Token &RawToken) {
+  RawLex.LexFromRawLexer(RawToken);
+  if (RawToken.is(tok::raw_identifier))
+    PP.LookUpIdentifierInfo(RawToken);
+  if (RawToken.is(tok::identifier))
+    return RawToken.getIdentifierInfo()->getName();
+  return StringRef();
+}
+
+// Expand __has_include and __has_include_next if possible. If there's no
+// definitive answer return false.
+bool InclusionRewriter::HandleHasInclude(
+    FileID FileId, Lexer &RawLex, const DirectoryLookup *Lookup, Token &Tok,
+    bool &FileExists) {
+  // Lex the opening paren.
+  RawLex.LexFromRawLexer(Tok);
+  if (Tok.isNot(tok::l_paren))
+    return false;
+
+  RawLex.LexFromRawLexer(Tok);
+
+  SmallString<128> FilenameBuffer;
+  StringRef Filename;
+  // Since the raw lexer doesn't give us angle_literals we have to parse them
+  // ourselves.
+  // FIXME: What to do if the file name is a macro?
+  if (Tok.is(tok::less)) {
+    RawLex.LexFromRawLexer(Tok);
+
+    FilenameBuffer += '<';
+    do {
+      if (Tok.is(tok::eod)) // Sanity check.
+        return false;
+
+      if (Tok.is(tok::raw_identifier))
+        PP.LookUpIdentifierInfo(Tok);
+
+      // Get the string piece.
+      SmallVector<char, 128> TmpBuffer;
+      bool Invalid = false;
+      StringRef TmpName = PP.getSpelling(Tok, TmpBuffer, &Invalid);
+      if (Invalid)
+        return false;
+
+      FilenameBuffer += TmpName;
+
+      RawLex.LexFromRawLexer(Tok);
+    } while (Tok.isNot(tok::greater));
+
+    FilenameBuffer += '>';
+    Filename = FilenameBuffer;
+  } else {
+    if (Tok.isNot(tok::string_literal))
+      return false;
+
+    bool Invalid = false;
+    Filename = PP.getSpelling(Tok, FilenameBuffer, &Invalid);
+    if (Invalid)
+      return false;
+  }
+
+  // Lex the closing paren.
+  RawLex.LexFromRawLexer(Tok);
+  if (Tok.isNot(tok::r_paren))
+    return false;
+
+  // Now ask HeaderInfo if it knows about the header.
+  // FIXME: Subframeworks aren't handled here. Do we care?
+  bool isAngled = PP.GetIncludeFilenameSpelling(Tok.getLocation(), Filename);
+  const DirectoryLookup *CurDir;
+  const FileEntry *File = PP.getHeaderSearchInfo().LookupFile(
+      Filename, SourceLocation(), isAngled, nullptr, CurDir,
+      PP.getSourceManager().getFileEntryForID(FileId), nullptr, nullptr,
+      nullptr, false);
+
+  FileExists = File != nullptr;
+  return true;
+}
+
+/// Use a raw lexer to analyze \p FileId, incrementally copying parts of it
+/// and including content of included files recursively.
+bool InclusionRewriter::Process(FileID FileId,
+                                SrcMgr::CharacteristicKind FileType)
+{
+  bool Invalid;
+  const MemoryBuffer &FromFile = *SM.getBuffer(FileId, &Invalid);
+  if (Invalid) // invalid inclusion
+    return false;
+  const char *FileName = FromFile.getBufferIdentifier();
+  Lexer RawLex(FileId, &FromFile, PP.getSourceManager(), PP.getLangOpts());
+  RawLex.SetCommentRetentionState(false);
+
+  StringRef EOL = DetectEOL(FromFile);
+
+  // Per the GNU docs: "1" indicates entering a new file.
+  if (FileId == SM.getMainFileID() || FileId == PP.getPredefinesFileID())
+    WriteLineInfo(FileName, 1, FileType, EOL, "");
+  else
+    WriteLineInfo(FileName, 1, FileType, EOL, " 1");
+
+  if (SM.getFileIDSize(FileId) == 0)
+    return false;
+
+  // The next byte to be copied from the source file, which may be non-zero if
+  // the lexer handled a BOM.
+  unsigned NextToWrite = SM.getFileOffset(RawLex.getSourceLocation());
+  assert(SM.getLineNumber(FileId, NextToWrite) == 1);
+  int Line = 1; // The current input file line number.
+
+  Token RawToken;
+  RawLex.LexFromRawLexer(RawToken);
+
+  // TODO: Consider adding a switch that strips possibly unimportant content,
+  // such as comments, to reduce the size of repro files.
+  while (RawToken.isNot(tok::eof)) {
+    if (RawToken.is(tok::hash) && RawToken.isAtStartOfLine()) {
+      RawLex.setParsingPreprocessorDirective(true);
+      Token HashToken = RawToken;
+      RawLex.LexFromRawLexer(RawToken);
+      if (RawToken.is(tok::raw_identifier))
+        PP.LookUpIdentifierInfo(RawToken);
+      if (RawToken.getIdentifierInfo() != nullptr) {
+        switch (RawToken.getIdentifierInfo()->getPPKeywordID()) {
+          case tok::pp_include:
+          case tok::pp_include_next:
+          case tok::pp_import: {
+            CommentOutDirective(RawLex, HashToken, FromFile, EOL, NextToWrite,
+              Line);
+            if (FileId != PP.getPredefinesFileID())
+              WriteLineInfo(FileName, Line - 1, FileType, EOL, "");
+            StringRef LineInfoExtra;
+            if (const FileChange *Change = FindFileChangeLocation(
+                HashToken.getLocation())) {
+              if (Change->Mod) {
+                WriteImplicitModuleImport(Change->Mod, EOL);
+
+              // else now include and recursively process the file
+              } else if (Process(Change->Id, Change->FileType)) {
+                // and set lineinfo back to this file, if the nested one was
+                // actually included
+                // `2' indicates returning to a file (after having included
+                // another file.
+                LineInfoExtra = " 2";
+              }
+            }
+            // fix up lineinfo (since commented out directive changed line
+            // numbers) for inclusions that were skipped due to header guards
+            WriteLineInfo(FileName, Line, FileType, EOL, LineInfoExtra);
+            break;
+          }
+          case tok::pp_pragma: {
+            StringRef Identifier = NextIdentifierName(RawLex, RawToken);
+            if (Identifier == "clang" || Identifier == "GCC") {
+              if (NextIdentifierName(RawLex, RawToken) == "system_header") {
+                // keep the directive in, commented out
+                CommentOutDirective(RawLex, HashToken, FromFile, EOL,
+                  NextToWrite, Line);
+                // update our own type
+                FileType = SM.getFileCharacteristic(RawToken.getLocation());
+                WriteLineInfo(FileName, Line, FileType, EOL);
+              }
+            } else if (Identifier == "once") {
+              // keep the directive in, commented out
+              CommentOutDirective(RawLex, HashToken, FromFile, EOL,
+                NextToWrite, Line);
+              WriteLineInfo(FileName, Line, FileType, EOL);
+            }
+            break;
+          }
+          case tok::pp_if:
+          case tok::pp_elif: {
+            bool elif = (RawToken.getIdentifierInfo()->getPPKeywordID() ==
+                         tok::pp_elif);
+            // Rewrite special builtin macros to avoid pulling in host details.
+            do {
+              // Walk over the directive.
+              RawLex.LexFromRawLexer(RawToken);
+              if (RawToken.is(tok::raw_identifier))
+                PP.LookUpIdentifierInfo(RawToken);
+
+              if (RawToken.is(tok::identifier)) {
+                bool HasFile;
+                SourceLocation Loc = RawToken.getLocation();
+
+                // Rewrite __has_include(x)
+                if (RawToken.getIdentifierInfo()->isStr("__has_include")) {
+                  if (!HandleHasInclude(FileId, RawLex, nullptr, RawToken,
+                                        HasFile))
+                    continue;
+                  // Rewrite __has_include_next(x)
+                } else if (RawToken.getIdentifierInfo()->isStr(
+                               "__has_include_next")) {
+                  const DirectoryLookup *Lookup = PP.GetCurDirLookup();
+                  if (Lookup)
+                    ++Lookup;
+
+                  if (!HandleHasInclude(FileId, RawLex, Lookup, RawToken,
+                                        HasFile))
+                    continue;
+                } else {
+                  continue;
+                }
+                // Replace the macro with (0) or (1), followed by the commented
+                // out macro for reference.
+                OutputContentUpTo(FromFile, NextToWrite, SM.getFileOffset(Loc),
+                                  EOL, Line, false);
+                OS << '(' << (int) HasFile << ")/*";
+                OutputContentUpTo(FromFile, NextToWrite,
+                                  SM.getFileOffset(RawToken.getLocation()) +
+                                  RawToken.getLength(),
+                                  EOL, Line, false);
+                OS << "*/";
+              }
+            } while (RawToken.isNot(tok::eod));
+            if (elif) {
+              OutputContentUpTo(FromFile, NextToWrite,
+                                SM.getFileOffset(RawToken.getLocation()) +
+                                    RawToken.getLength(),
+                                EOL, Line, /*EnsureNewLine*/ true);
+              WriteLineInfo(FileName, Line, FileType, EOL);
+            }
+            break;
+          }
+          case tok::pp_endif:
+          case tok::pp_else: {
+            // We surround every #include by #if 0 to comment it out, but that
+            // changes line numbers. These are fixed up right after that, but
+            // the whole #include could be inside a preprocessor conditional
+            // that is not processed. So it is necessary to fix the line
+            // numbers one the next line after each #else/#endif as well.
+            RawLex.SetKeepWhitespaceMode(true);
+            do {
+              RawLex.LexFromRawLexer(RawToken);
+            } while (RawToken.isNot(tok::eod) && RawToken.isNot(tok::eof));
+            OutputContentUpTo(
+                FromFile, NextToWrite,
+                SM.getFileOffset(RawToken.getLocation()) + RawToken.getLength(),
+                EOL, Line, /*EnsureNewLine*/ true);
+            WriteLineInfo(FileName, Line, FileType, EOL);
+            RawLex.SetKeepWhitespaceMode(false);
+          }
+          default:
+            break;
+        }
+      }
+      RawLex.setParsingPreprocessorDirective(false);
+    }
+    RawLex.LexFromRawLexer(RawToken);
+  }
+  OutputContentUpTo(FromFile, NextToWrite,
+    SM.getFileOffset(SM.getLocForEndOfFile(FileId)), EOL, Line,
+    /*EnsureNewline*/true);
+  return true;
+}
+
+/// InclusionRewriterInInput - Implement -frewrite-includes mode.
+void clang::RewriteIncludesInInput(Preprocessor &PP, raw_ostream *OS,
+                                   const PreprocessorOutputOptions &Opts) {
+  SourceManager &SM = PP.getSourceManager();
+  InclusionRewriter *Rewrite = new InclusionRewriter(PP, *OS,
+                                                     Opts.ShowLineMarkers);
+  PP.addPPCallbacks(Rewrite);
+  PP.IgnorePragmas();
+
+  // First let the preprocessor process the entire file and call callbacks.
+  // Callbacks will record which #include's were actually performed.
+  PP.EnterMainSourceFile();
+  Token Tok;
+  // Only preprocessor directives matter here, so disable macro expansion
+  // everywhere else as an optimization.
+  // TODO: It would be even faster if the preprocessor could be switched
+  // to a mode where it would parse only preprocessor directives and comments,
+  // nothing else matters for parsing or processing.
+  PP.SetMacroExpansionOnlyInDirectives();
+  do {
+    PP.Lex(Tok);
+  } while (Tok.isNot(tok::eof));
+  Rewrite->setPredefinesBuffer(SM.getBuffer(PP.getPredefinesFileID()));
+  Rewrite->Process(PP.getPredefinesFileID(), SrcMgr::C_User);
+  Rewrite->Process(SM.getMainFileID(), SrcMgr::C_User);
+  OS->flush();
+}
diff --git a/lib/Frontend/Rewrite/Makefile b/lib/Frontend/Rewrite/Makefile
new file mode 100644
index 000000000000..1d565477053c
--- /dev/null
+++ b/lib/Frontend/Rewrite/Makefile
@@ -0,0 +1,22 @@
+##===- clang/lib/Rewrite/Makefile --------------------------*- Makefile -*-===##
+# 
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+# 
+##===----------------------------------------------------------------------===##
+#
+# This implements code transformation / rewriting facilities.
+#
+##===----------------------------------------------------------------------===##
+
+CLANG_LEVEL := ../../..
+LIBRARYNAME := clangRewriteFrontend
+
+include $(CLANG_LEVEL)/Makefile
+
+ifeq ($(ENABLE_CLANG_ARCMT),1)
+  CXX.Flags += -DCLANG_ENABLE_OBJC_REWRITER
+endif
+
diff --git a/lib/Frontend/Rewrite/RewriteMacros.cpp b/lib/Frontend/Rewrite/RewriteMacros.cpp
new file mode 100644
index 000000000000..0d0a991fa6f9
--- /dev/null
+++ b/lib/Frontend/Rewrite/RewriteMacros.cpp
@@ -0,0 +1,217 @@
+//===--- RewriteMacros.cpp - Rewrite macros into their expansions ---------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This code rewrites macro invocations into their expansions.  This gives you
+// a macro expanded file that retains comments and #includes.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Rewrite/Frontend/Rewriters.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Rewrite/Core/Rewriter.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cstdio>
+#include <memory>
+
+using namespace clang;
+
+/// isSameToken - Return true if the two specified tokens start have the same
+/// content.
+static bool isSameToken(Token &RawTok, Token &PPTok) {
+  // If two tokens have the same kind and the same identifier info, they are
+  // obviously the same.
+  if (PPTok.getKind() == RawTok.getKind() &&
+      PPTok.getIdentifierInfo() == RawTok.getIdentifierInfo())
+    return true;
+
+  // Otherwise, if they are different but have the same identifier info, they
+  // are also considered to be the same.  This allows keywords and raw lexed
+  // identifiers with the same name to be treated the same.
+  if (PPTok.getIdentifierInfo() &&
+      PPTok.getIdentifierInfo() == RawTok.getIdentifierInfo())
+    return true;
+
+  return false;
+}
+
+
+/// GetNextRawTok - Return the next raw token in the stream, skipping over
+/// comments if ReturnComment is false.
+static const Token &GetNextRawTok(const std::vector<Token> &RawTokens,
+                                  unsigned &CurTok, bool ReturnComment) {
+  assert(CurTok < RawTokens.size() && "Overran eof!");
+
+  // If the client doesn't want comments and we have one, skip it.
+  if (!ReturnComment && RawTokens[CurTok].is(tok::comment))
+    ++CurTok;
+
+  return RawTokens[CurTok++];
+}
+
+
+/// LexRawTokensFromMainFile - Lets all the raw tokens from the main file into
+/// the specified vector.
+static void LexRawTokensFromMainFile(Preprocessor &PP,
+                                     std::vector<Token> &RawTokens) {
+  SourceManager &SM = PP.getSourceManager();
+
+  // Create a lexer to lex all the tokens of the main file in raw mode.  Even
+  // though it is in raw mode, it will not return comments.
+  const llvm::MemoryBuffer *FromFile = SM.getBuffer(SM.getMainFileID());
+  Lexer RawLex(SM.getMainFileID(), FromFile, SM, PP.getLangOpts());
+
+  // Switch on comment lexing because we really do want them.
+  RawLex.SetCommentRetentionState(true);
+
+  Token RawTok;
+  do {
+    RawLex.LexFromRawLexer(RawTok);
+
+    // If we have an identifier with no identifier info for our raw token, look
+    // up the indentifier info.  This is important for equality comparison of
+    // identifier tokens.
+    if (RawTok.is(tok::raw_identifier))
+      PP.LookUpIdentifierInfo(RawTok);
+
+    RawTokens.push_back(RawTok);
+  } while (RawTok.isNot(tok::eof));
+}
+
+
+/// RewriteMacrosInInput - Implement -rewrite-macros mode.
+void clang::RewriteMacrosInInput(Preprocessor &PP, raw_ostream *OS) {
+  SourceManager &SM = PP.getSourceManager();
+
+  Rewriter Rewrite;
+  Rewrite.setSourceMgr(SM, PP.getLangOpts());
+  RewriteBuffer &RB = Rewrite.getEditBuffer(SM.getMainFileID());
+
+  std::vector<Token> RawTokens;
+  LexRawTokensFromMainFile(PP, RawTokens);
+  unsigned CurRawTok = 0;
+  Token RawTok = GetNextRawTok(RawTokens, CurRawTok, false);
+
+
+  // Get the first preprocessing token.
+  PP.EnterMainSourceFile();
+  Token PPTok;
+  PP.Lex(PPTok);
+
+  // Preprocess the input file in parallel with raw lexing the main file. Ignore
+  // all tokens that are preprocessed from a file other than the main file (e.g.
+  // a header).  If we see tokens that are in the preprocessed file but not the
+  // lexed file, we have a macro expansion.  If we see tokens in the lexed file
+  // that aren't in the preprocessed view, we have macros that expand to no
+  // tokens, or macro arguments etc.
+  while (RawTok.isNot(tok::eof) || PPTok.isNot(tok::eof)) {
+    SourceLocation PPLoc = SM.getExpansionLoc(PPTok.getLocation());
+
+    // If PPTok is from a different source file, ignore it.
+    if (!SM.isWrittenInMainFile(PPLoc)) {
+      PP.Lex(PPTok);
+      continue;
+    }
+
+    // If the raw file hits a preprocessor directive, they will be extra tokens
+    // in the raw file that don't exist in the preprocsesed file.  However, we
+    // choose to preserve them in the output file and otherwise handle them
+    // specially.
+    if (RawTok.is(tok::hash) && RawTok.isAtStartOfLine()) {
+      // If this is a #warning directive or #pragma mark (GNU extensions),
+      // comment the line out.
+      if (RawTokens[CurRawTok].is(tok::identifier)) {
+        const IdentifierInfo *II = RawTokens[CurRawTok].getIdentifierInfo();
+        if (II->getName() == "warning") {
+          // Comment out #warning.
+          RB.InsertTextAfter(SM.getFileOffset(RawTok.getLocation()), "//");
+        } else if (II->getName() == "pragma" &&
+                   RawTokens[CurRawTok+1].is(tok::identifier) &&
+                   (RawTokens[CurRawTok+1].getIdentifierInfo()->getName() ==
+                    "mark")) {
+          // Comment out #pragma mark.
+          RB.InsertTextAfter(SM.getFileOffset(RawTok.getLocation()), "//");
+        }
+      }
+
+      // Otherwise, if this is a #include or some other directive, just leave it
+      // in the file by skipping over the line.
+      RawTok = GetNextRawTok(RawTokens, CurRawTok, false);
+      while (!RawTok.isAtStartOfLine() && RawTok.isNot(tok::eof))
+        RawTok = GetNextRawTok(RawTokens, CurRawTok, false);
+      continue;
+    }
+
+    // Okay, both tokens are from the same file.  Get their offsets from the
+    // start of the file.
+    unsigned PPOffs = SM.getFileOffset(PPLoc);
+    unsigned RawOffs = SM.getFileOffset(RawTok.getLocation());
+
+    // If the offsets are the same and the token kind is the same, ignore them.
+    if (PPOffs == RawOffs && isSameToken(RawTok, PPTok)) {
+      RawTok = GetNextRawTok(RawTokens, CurRawTok, false);
+      PP.Lex(PPTok);
+      continue;
+    }
+
+    // If the PP token is farther along than the raw token, something was
+    // deleted.  Comment out the raw token.
+    if (RawOffs <= PPOffs) {
+      // Comment out a whole run of tokens instead of bracketing each one with
+      // comments.  Add a leading space if RawTok didn't have one.
+      bool HasSpace = RawTok.hasLeadingSpace();
+      RB.InsertTextAfter(RawOffs, &" /*"[HasSpace]);
+      unsigned EndPos;
+
+      do {
+        EndPos = RawOffs+RawTok.getLength();
+
+        RawTok = GetNextRawTok(RawTokens, CurRawTok, true);
+        RawOffs = SM.getFileOffset(RawTok.getLocation());
+
+        if (RawTok.is(tok::comment)) {
+          // Skip past the comment.
+          RawTok = GetNextRawTok(RawTokens, CurRawTok, false);
+          break;
+        }
+
+      } while (RawOffs <= PPOffs && !RawTok.isAtStartOfLine() &&
+               (PPOffs != RawOffs || !isSameToken(RawTok, PPTok)));
+
+      RB.InsertTextBefore(EndPos, "*/");
+      continue;
+    }
+
+    // Otherwise, there was a replacement an expansion.  Insert the new token
+    // in the output buffer.  Insert the whole run of new tokens at once to get
+    // them in the right order.
+    unsigned InsertPos = PPOffs;
+    std::string Expansion;
+    while (PPOffs < RawOffs) {
+      Expansion += ' ' + PP.getSpelling(PPTok);
+      PP.Lex(PPTok);
+      PPLoc = SM.getExpansionLoc(PPTok.getLocation());
+      PPOffs = SM.getFileOffset(PPLoc);
+    }
+    Expansion += ' ';
+    RB.InsertTextBefore(InsertPos, Expansion);
+  }
+
+  // Get the buffer corresponding to MainFileID.  If we haven't changed it, then
+  // we are done.
+  if (const RewriteBuffer *RewriteBuf =
+      Rewrite.getRewriteBufferFor(SM.getMainFileID())) {
+    //printf("Changed:\n");
+    *OS << std::string(RewriteBuf->begin(), RewriteBuf->end());
+  } else {
+    fprintf(stderr, "No changes\n");
+  }
+  OS->flush();
+}
diff --git a/lib/Frontend/Rewrite/RewriteModernObjC.cpp b/lib/Frontend/Rewrite/RewriteModernObjC.cpp
new file mode 100644
index 000000000000..3e18a8b415a3
--- /dev/null
+++ b/lib/Frontend/Rewrite/RewriteModernObjC.cpp
@@ -0,0 +1,7760 @@
+//===--- RewriteObjC.cpp - Playground for the code rewriter ---------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Hacks and fun related to the code rewriter.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Rewrite/Frontend/ASTConsumers.h"
+#include "clang/AST/AST.h"
+#include "clang/AST/ASTConsumer.h"
+#include "clang/AST/Attr.h"
+#include "clang/AST/ParentMap.h"
+#include "clang/Basic/CharInfo.h"
+#include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/IdentifierTable.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Basic/TargetInfo.h"
+#include "clang/Lex/Lexer.h"
+#include "clang/Rewrite/Core/Rewriter.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/raw_ostream.h"
+#include <memory>
+
+#ifdef CLANG_ENABLE_OBJC_REWRITER
+
+using namespace clang;
+using llvm::utostr;
+
+namespace {
+  class RewriteModernObjC : public ASTConsumer {
+  protected:
+    
+    enum {
+      BLOCK_FIELD_IS_OBJECT   =  3,  /* id, NSObject, __attribute__((NSObject)),
+                                        block, ... */
+      BLOCK_FIELD_IS_BLOCK    =  7,  /* a block variable */
+      BLOCK_FIELD_IS_BYREF    =  8,  /* the on stack structure holding the 
+                                        __block variable */
+      BLOCK_FIELD_IS_WEAK     = 16,  /* declared __weak, only used in byref copy
+                                        helpers */
+      BLOCK_BYREF_CALLER      = 128, /* called from __block (byref) copy/dispose
+                                        support routines */
+      BLOCK_BYREF_CURRENT_MAX = 256
+    };
+    
+    enum {
+      BLOCK_NEEDS_FREE =        (1 << 24),
+      BLOCK_HAS_COPY_DISPOSE =  (1 << 25),
+      BLOCK_HAS_CXX_OBJ =       (1 << 26),
+      BLOCK_IS_GC =             (1 << 27),
+      BLOCK_IS_GLOBAL =         (1 << 28),
+      BLOCK_HAS_DESCRIPTOR =    (1 << 29)
+    };
+    
+    Rewriter Rewrite;
+    DiagnosticsEngine &Diags;
+    const LangOptions &LangOpts;
+    ASTContext *Context;
+    SourceManager *SM;
+    TranslationUnitDecl *TUDecl;
+    FileID MainFileID;
+    const char *MainFileStart, *MainFileEnd;
+    Stmt *CurrentBody;
+    ParentMap *PropParentMap; // created lazily.
+    std::string InFileName;
+    raw_ostream* OutFile;
+    std::string Preamble;
+    
+    TypeDecl *ProtocolTypeDecl;
+    VarDecl *GlobalVarDecl;
+    Expr *GlobalConstructionExp;
+    unsigned RewriteFailedDiag;
+    unsigned GlobalBlockRewriteFailedDiag;
+    // ObjC string constant support.
+    unsigned NumObjCStringLiterals;
+    VarDecl *ConstantStringClassReference;
+    RecordDecl *NSStringRecord;
+
+    // ObjC foreach break/continue generation support.
+    int BcLabelCount;
+    
+    unsigned TryFinallyContainsReturnDiag;
+    // Needed for super.
+    ObjCMethodDecl *CurMethodDef;
+    RecordDecl *SuperStructDecl;
+    RecordDecl *ConstantStringDecl;
+    
+    FunctionDecl *MsgSendFunctionDecl;
+    FunctionDecl *MsgSendSuperFunctionDecl;
+    FunctionDecl *MsgSendStretFunctionDecl;
+    FunctionDecl *MsgSendSuperStretFunctionDecl;
+    FunctionDecl *MsgSendFpretFunctionDecl;
+    FunctionDecl *GetClassFunctionDecl;
+    FunctionDecl *GetMetaClassFunctionDecl;
+    FunctionDecl *GetSuperClassFunctionDecl;
+    FunctionDecl *SelGetUidFunctionDecl;
+    FunctionDecl *CFStringFunctionDecl;
+    FunctionDecl *SuperConstructorFunctionDecl;
+    FunctionDecl *CurFunctionDef;
+
+    /* Misc. containers needed for meta-data rewrite. */
+    SmallVector<ObjCImplementationDecl *, 8> ClassImplementation;
+    SmallVector<ObjCCategoryImplDecl *, 8> CategoryImplementation;
+    llvm::SmallPtrSet<ObjCInterfaceDecl*, 8> ObjCSynthesizedStructs;
+    llvm::SmallPtrSet<ObjCProtocolDecl*, 8> ObjCSynthesizedProtocols;
+    llvm::SmallPtrSet<ObjCInterfaceDecl*, 8> ObjCWrittenInterfaces;
+    llvm::SmallPtrSet<TagDecl*, 32> GlobalDefinedTags;
+    SmallVector<ObjCInterfaceDecl*, 32> ObjCInterfacesSeen;
+    /// DefinedNonLazyClasses - List of defined "non-lazy" classes.
+    SmallVector<ObjCInterfaceDecl*, 8> DefinedNonLazyClasses;
+    
+    /// DefinedNonLazyCategories - List of defined "non-lazy" categories.
+    SmallVector<ObjCCategoryDecl *, 8> DefinedNonLazyCategories;
+    
+    SmallVector<Stmt *, 32> Stmts;
+    SmallVector<int, 8> ObjCBcLabelNo;
+    // Remember all the @protocol(<expr>) expressions.
+    llvm::SmallPtrSet<ObjCProtocolDecl *, 32> ProtocolExprDecls;
+    
+    llvm::DenseSet<uint64_t> CopyDestroyCache;
+
+    // Block expressions.
+    SmallVector<BlockExpr *, 32> Blocks;
+    SmallVector<int, 32> InnerDeclRefsCount;
+    SmallVector<DeclRefExpr *, 32> InnerDeclRefs;
+    
+    SmallVector<DeclRefExpr *, 32> BlockDeclRefs;
+
+    
+    // Block related declarations.
+    SmallVector<ValueDecl *, 8> BlockByCopyDecls;
+    llvm::SmallPtrSet<ValueDecl *, 8> BlockByCopyDeclsPtrSet;
+    SmallVector<ValueDecl *, 8> BlockByRefDecls;
+    llvm::SmallPtrSet<ValueDecl *, 8> BlockByRefDeclsPtrSet;
+    llvm::DenseMap<ValueDecl *, unsigned> BlockByRefDeclNo;
+    llvm::SmallPtrSet<ValueDecl *, 8> ImportedBlockDecls;
+    llvm::SmallPtrSet<VarDecl *, 8> ImportedLocalExternalDecls;
+    
+    llvm::DenseMap<BlockExpr *, std::string> RewrittenBlockExprs;
+    llvm::DenseMap<ObjCInterfaceDecl *, 
+                    llvm::SmallPtrSet<ObjCIvarDecl *, 8> > ReferencedIvars;
+    
+    // ivar bitfield grouping containers
+    llvm::DenseSet<const ObjCInterfaceDecl *> ObjCInterefaceHasBitfieldGroups;
+    llvm::DenseMap<const ObjCIvarDecl* , unsigned> IvarGroupNumber;
+    // This container maps an <class, group number for ivar> tuple to the type
+    // of the struct where the bitfield belongs.
+    llvm::DenseMap<std::pair<const ObjCInterfaceDecl*, unsigned>, QualType> GroupRecordType;
+    SmallVector<FunctionDecl*, 32> FunctionDefinitionsSeen;
+    
+    // This maps an original source AST to it's rewritten form. This allows
+    // us to avoid rewriting the same node twice (which is very uncommon).
+    // This is needed to support some of the exotic property rewriting.
+    llvm::DenseMap<Stmt *, Stmt *> ReplacedNodes;
+
+    // Needed for header files being rewritten
+    bool IsHeader;
+    bool SilenceRewriteMacroWarning;
+    bool GenerateLineInfo;
+    bool objc_impl_method;
+    
+    bool DisableReplaceStmt;
+    class DisableReplaceStmtScope {
+      RewriteModernObjC &R;
+      bool SavedValue;
+    
+    public:
+      DisableReplaceStmtScope(RewriteModernObjC &R)
+        : R(R), SavedValue(R.DisableReplaceStmt) {
+        R.DisableReplaceStmt = true;
+      }
+      ~DisableReplaceStmtScope() {
+        R.DisableReplaceStmt = SavedValue;
+      }
+    };
+    void InitializeCommon(ASTContext &context);
+
+  public:
+    llvm::DenseMap<ObjCMethodDecl*, std::string> MethodInternalNames;
+    // Top Level Driver code.
+    bool HandleTopLevelDecl(DeclGroupRef D) override {
+      for (DeclGroupRef::iterator I = D.begin(), E = D.end(); I != E; ++I) {
+        if (ObjCInterfaceDecl *Class = dyn_cast<ObjCInterfaceDecl>(*I)) {
+          if (!Class->isThisDeclarationADefinition()) {
+            RewriteForwardClassDecl(D);
+            break;
+          } else {
+            // Keep track of all interface declarations seen.
+            ObjCInterfacesSeen.push_back(Class);
+            break;
+          }
+        }
+
+        if (ObjCProtocolDecl *Proto = dyn_cast<ObjCProtocolDecl>(*I)) {
+          if (!Proto->isThisDeclarationADefinition()) {
+            RewriteForwardProtocolDecl(D);
+            break;
+          }
+        }
+
+        if (FunctionDecl *FDecl = dyn_cast<FunctionDecl>(*I)) {
+          // Under modern abi, we cannot translate body of the function
+          // yet until all class extensions and its implementation is seen.
+          // This is because they may introduce new bitfields which must go
+          // into their grouping struct.
+          if (FDecl->isThisDeclarationADefinition() &&
+              // Not c functions defined inside an objc container.
+              !FDecl->isTopLevelDeclInObjCContainer()) {
+            FunctionDefinitionsSeen.push_back(FDecl);
+            break;
+          }
+        }
+        HandleTopLevelSingleDecl(*I);
+      }
+      return true;
+    }
+
+    void HandleTopLevelDeclInObjCContainer(DeclGroupRef D) override {
+      for (DeclGroupRef::iterator I = D.begin(), E = D.end(); I != E; ++I) {
+        if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(*I)) {
+          if (isTopLevelBlockPointerType(TD->getUnderlyingType()))
+            RewriteBlockPointerDecl(TD);
+          else if (TD->getUnderlyingType()->isFunctionPointerType())
+            CheckFunctionPointerDecl(TD->getUnderlyingType(), TD);
+          else
+            RewriteObjCQualifiedInterfaceTypes(TD);
+        }
+      }
+      return;
+    }
+    
+    void HandleTopLevelSingleDecl(Decl *D);
+    void HandleDeclInMainFile(Decl *D);
+    RewriteModernObjC(std::string inFile, raw_ostream *OS,
+                DiagnosticsEngine &D, const LangOptions &LOpts,
+                bool silenceMacroWarn, bool LineInfo);
+    
+    ~RewriteModernObjC() {}
+
+    void HandleTranslationUnit(ASTContext &C) override;
+
+    void ReplaceStmt(Stmt *Old, Stmt *New) {
+      Stmt *ReplacingStmt = ReplacedNodes[Old];
+
+      if (ReplacingStmt)
+        return; // We can't rewrite the same node twice.
+
+      if (DisableReplaceStmt)
+        return;
+
+      // If replacement succeeded or warning disabled return with no warning.
+      if (!Rewrite.ReplaceStmt(Old, New)) {
+        ReplacedNodes[Old] = New;
+        return;
+      }
+      if (SilenceRewriteMacroWarning)
+        return;
+      Diags.Report(Context->getFullLoc(Old->getLocStart()), RewriteFailedDiag)
+                   << Old->getSourceRange();
+    }
+
+    void ReplaceStmtWithRange(Stmt *Old, Stmt *New, SourceRange SrcRange) {
+      assert(Old != nullptr && New != nullptr && "Expected non-null Stmt's");
+      if (DisableReplaceStmt)
+        return;
+
+      // Measure the old text.
+      int Size = Rewrite.getRangeSize(SrcRange);
+      if (Size == -1) {
+        Diags.Report(Context->getFullLoc(Old->getLocStart()), RewriteFailedDiag)
+                     << Old->getSourceRange();
+        return;
+      }
+      // Get the new text.
+      std::string SStr;
+      llvm::raw_string_ostream S(SStr);
+      New->printPretty(S, nullptr, PrintingPolicy(LangOpts));
+      const std::string &Str = S.str();
+
+      // If replacement succeeded or warning disabled return with no warning.
+      if (!Rewrite.ReplaceText(SrcRange.getBegin(), Size, Str)) {
+        ReplacedNodes[Old] = New;
+        return;
+      }
+      if (SilenceRewriteMacroWarning)
+        return;
+      Diags.Report(Context->getFullLoc(Old->getLocStart()), RewriteFailedDiag)
+                   << Old->getSourceRange();
+    }
+
+    void InsertText(SourceLocation Loc, StringRef Str,
+                    bool InsertAfter = true) {
+      // If insertion succeeded or warning disabled return with no warning.
+      if (!Rewrite.InsertText(Loc, Str, InsertAfter) ||
+          SilenceRewriteMacroWarning)
+        return;
+
+      Diags.Report(Context->getFullLoc(Loc), RewriteFailedDiag);
+    }
+
+    void ReplaceText(SourceLocation Start, unsigned OrigLength,
+                     StringRef Str) {
+      // If removal succeeded or warning disabled return with no warning.
+      if (!Rewrite.ReplaceText(Start, OrigLength, Str) ||
+          SilenceRewriteMacroWarning)
+        return;
+
+      Diags.Report(Context->getFullLoc(Start), RewriteFailedDiag);
+    }
+
+    // Syntactic Rewriting.
+    void RewriteRecordBody(RecordDecl *RD);
+    void RewriteInclude();
+    void RewriteLineDirective(const Decl *D);
+    void ConvertSourceLocationToLineDirective(SourceLocation Loc,
+                                              std::string &LineString);
+    void RewriteForwardClassDecl(DeclGroupRef D);
+    void RewriteForwardClassDecl(const SmallVectorImpl<Decl *> &DG);
+    void RewriteForwardClassEpilogue(ObjCInterfaceDecl *ClassDecl, 
+                                     const std::string &typedefString);
+    void RewriteImplementations();
+    void RewritePropertyImplDecl(ObjCPropertyImplDecl *PID,
+                                 ObjCImplementationDecl *IMD,
+                                 ObjCCategoryImplDecl *CID);
+    void RewriteInterfaceDecl(ObjCInterfaceDecl *Dcl);
+    void RewriteImplementationDecl(Decl *Dcl);
+    void RewriteObjCMethodDecl(const ObjCInterfaceDecl *IDecl,
+                               ObjCMethodDecl *MDecl, std::string &ResultStr);
+    void RewriteTypeIntoString(QualType T, std::string &ResultStr,
+                               const FunctionType *&FPRetType);
+    void RewriteByRefString(std::string &ResultStr, const std::string &Name,
+                            ValueDecl *VD, bool def=false);
+    void RewriteCategoryDecl(ObjCCategoryDecl *Dcl);
+    void RewriteProtocolDecl(ObjCProtocolDecl *Dcl);
+    void RewriteForwardProtocolDecl(DeclGroupRef D);
+    void RewriteForwardProtocolDecl(const SmallVectorImpl<Decl *> &DG);
+    void RewriteMethodDeclaration(ObjCMethodDecl *Method);
+    void RewriteProperty(ObjCPropertyDecl *prop);
+    void RewriteFunctionDecl(FunctionDecl *FD);
+    void RewriteBlockPointerType(std::string& Str, QualType Type);
+    void RewriteBlockPointerTypeVariable(std::string& Str, ValueDecl *VD);
+    void RewriteBlockLiteralFunctionDecl(FunctionDecl *FD);
+    void RewriteObjCQualifiedInterfaceTypes(Decl *Dcl);
+    void RewriteTypeOfDecl(VarDecl *VD);
+    void RewriteObjCQualifiedInterfaceTypes(Expr *E);
+    
+    std::string getIvarAccessString(ObjCIvarDecl *D);
+  
+    // Expression Rewriting.
+    Stmt *RewriteFunctionBodyOrGlobalInitializer(Stmt *S);
+    Stmt *RewriteAtEncode(ObjCEncodeExpr *Exp);
+    Stmt *RewritePropertyOrImplicitGetter(PseudoObjectExpr *Pseudo);
+    Stmt *RewritePropertyOrImplicitSetter(PseudoObjectExpr *Pseudo);
+    Stmt *RewriteAtSelector(ObjCSelectorExpr *Exp);
+    Stmt *RewriteMessageExpr(ObjCMessageExpr *Exp);
+    Stmt *RewriteObjCStringLiteral(ObjCStringLiteral *Exp);
+    Stmt *RewriteObjCBoolLiteralExpr(ObjCBoolLiteralExpr *Exp);
+    Stmt *RewriteObjCBoxedExpr(ObjCBoxedExpr *Exp);
+    Stmt *RewriteObjCArrayLiteralExpr(ObjCArrayLiteral *Exp);
+    Stmt *RewriteObjCDictionaryLiteralExpr(ObjCDictionaryLiteral *Exp);
+    Stmt *RewriteObjCProtocolExpr(ObjCProtocolExpr *Exp);
+    Stmt *RewriteObjCTryStmt(ObjCAtTryStmt *S);
+    Stmt *RewriteObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt  *S);
+    Stmt *RewriteObjCSynchronizedStmt(ObjCAtSynchronizedStmt *S);
+    Stmt *RewriteObjCThrowStmt(ObjCAtThrowStmt *S);
+    Stmt *RewriteObjCForCollectionStmt(ObjCForCollectionStmt *S,
+                                       SourceLocation OrigEnd);
+    Stmt *RewriteBreakStmt(BreakStmt *S);
+    Stmt *RewriteContinueStmt(ContinueStmt *S);
+    void RewriteCastExpr(CStyleCastExpr *CE);
+    void RewriteImplicitCastObjCExpr(CastExpr *IE);
+    void RewriteLinkageSpec(LinkageSpecDecl *LSD);
+    
+    // Computes ivar bitfield group no.
+    unsigned ObjCIvarBitfieldGroupNo(ObjCIvarDecl *IV);
+    // Names field decl. for ivar bitfield group.
+    void ObjCIvarBitfieldGroupDecl(ObjCIvarDecl *IV, std::string &Result);
+    // Names struct type for ivar bitfield group.
+    void ObjCIvarBitfieldGroupType(ObjCIvarDecl *IV, std::string &Result);
+    // Names symbol for ivar bitfield group field offset.
+    void ObjCIvarBitfieldGroupOffset(ObjCIvarDecl *IV, std::string &Result);
+    // Given an ivar bitfield, it builds (or finds) its group record type.
+    QualType GetGroupRecordTypeForObjCIvarBitfield(ObjCIvarDecl *IV);
+    QualType SynthesizeBitfieldGroupStructType(
+                                    ObjCIvarDecl *IV,
+                                    SmallVectorImpl<ObjCIvarDecl *> &IVars);
+    
+    // Block rewriting.
+    void RewriteBlocksInFunctionProtoType(QualType funcType, NamedDecl *D);
+    
+    // Block specific rewrite rules.
+    void RewriteBlockPointerDecl(NamedDecl *VD);
+    void RewriteByRefVar(VarDecl *VD, bool firstDecl, bool lastDecl);
+    Stmt *RewriteBlockDeclRefExpr(DeclRefExpr *VD);
+    Stmt *RewriteLocalVariableExternalStorage(DeclRefExpr *DRE);
+    void RewriteBlockPointerFunctionArgs(FunctionDecl *FD);
+    
+    void RewriteObjCInternalStruct(ObjCInterfaceDecl *CDecl,
+                                      std::string &Result);
+    
+    void RewriteObjCFieldDecl(FieldDecl *fieldDecl, std::string &Result);
+    bool IsTagDefinedInsideClass(ObjCContainerDecl *IDecl, TagDecl *Tag,
+                                 bool &IsNamedDefinition);
+    void RewriteLocallyDefinedNamedAggregates(FieldDecl *fieldDecl, 
+                                              std::string &Result);
+    
+    bool RewriteObjCFieldDeclType(QualType &Type, std::string &Result);
+    
+    void RewriteIvarOffsetSymbols(ObjCInterfaceDecl *CDecl,
+                                  std::string &Result);
+
+    void Initialize(ASTContext &context) override;
+
+    // Misc. AST transformation routines. Sometimes they end up calling
+    // rewriting routines on the new ASTs.
+    CallExpr *SynthesizeCallToFunctionDecl(FunctionDecl *FD,
+                                           Expr **args, unsigned nargs,
+                                           SourceLocation StartLoc=SourceLocation(),
+                                           SourceLocation EndLoc=SourceLocation());
+    
+    Expr *SynthMsgSendStretCallExpr(FunctionDecl *MsgSendStretFlavor,
+                                        QualType returnType, 
+                                        SmallVectorImpl<QualType> &ArgTypes,
+                                        SmallVectorImpl<Expr*> &MsgExprs,
+                                        ObjCMethodDecl *Method);
+
+    Stmt *SynthMessageExpr(ObjCMessageExpr *Exp,
+                           SourceLocation StartLoc=SourceLocation(),
+                           SourceLocation EndLoc=SourceLocation());
+    
+    void SynthCountByEnumWithState(std::string &buf);
+    void SynthMsgSendFunctionDecl();
+    void SynthMsgSendSuperFunctionDecl();
+    void SynthMsgSendStretFunctionDecl();
+    void SynthMsgSendFpretFunctionDecl();
+    void SynthMsgSendSuperStretFunctionDecl();
+    void SynthGetClassFunctionDecl();
+    void SynthGetMetaClassFunctionDecl();
+    void SynthGetSuperClassFunctionDecl();
+    void SynthSelGetUidFunctionDecl();
+    void SynthSuperConstructorFunctionDecl();
+    
+    // Rewriting metadata
+    template<typename MethodIterator>
+    void RewriteObjCMethodsMetaData(MethodIterator MethodBegin,
+                                    MethodIterator MethodEnd,
+                                    bool IsInstanceMethod,
+                                    StringRef prefix,
+                                    StringRef ClassName,
+                                    std::string &Result);
+    void RewriteObjCProtocolMetaData(ObjCProtocolDecl *Protocol,
+                                     std::string &Result);
+    void RewriteObjCProtocolListMetaData(
+                   const ObjCList<ObjCProtocolDecl> &Prots,
+                   StringRef prefix, StringRef ClassName, std::string &Result);
+    void RewriteObjCClassMetaData(ObjCImplementationDecl *IDecl,
+                                          std::string &Result);
+    void RewriteClassSetupInitHook(std::string &Result);
+    
+    void RewriteMetaDataIntoBuffer(std::string &Result);
+    void WriteImageInfo(std::string &Result);
+    void RewriteObjCCategoryImplDecl(ObjCCategoryImplDecl *CDecl,
+                                             std::string &Result);
+    void RewriteCategorySetupInitHook(std::string &Result);
+    
+    // Rewriting ivar
+    void RewriteIvarOffsetComputation(ObjCIvarDecl *ivar,
+                                              std::string &Result);
+    Stmt *RewriteObjCIvarRefExpr(ObjCIvarRefExpr *IV);
+
+    
+    std::string SynthesizeByrefCopyDestroyHelper(VarDecl *VD, int flag);
+    std::string SynthesizeBlockHelperFuncs(BlockExpr *CE, int i,
+                                      StringRef funcName, std::string Tag);
+    std::string SynthesizeBlockFunc(BlockExpr *CE, int i,
+                                      StringRef funcName, std::string Tag);
+    std::string SynthesizeBlockImpl(BlockExpr *CE, 
+                                    std::string Tag, std::string Desc);
+    std::string SynthesizeBlockDescriptor(std::string DescTag, 
+                                          std::string ImplTag,
+                                          int i, StringRef funcName,
+                                          unsigned hasCopy);
+    Stmt *SynthesizeBlockCall(CallExpr *Exp, const Expr* BlockExp);
+    void SynthesizeBlockLiterals(SourceLocation FunLocStart,
+                                 StringRef FunName);
+    FunctionDecl *SynthBlockInitFunctionDecl(StringRef name);
+    Stmt *SynthBlockInitExpr(BlockExpr *Exp,
+                      const SmallVectorImpl<DeclRefExpr *> &InnerBlockDeclRefs);
+
+    // Misc. helper routines.
+    QualType getProtocolType();
+    void WarnAboutReturnGotoStmts(Stmt *S);
+    void CheckFunctionPointerDecl(QualType dType, NamedDecl *ND);
+    void InsertBlockLiteralsWithinFunction(FunctionDecl *FD);
+    void InsertBlockLiteralsWithinMethod(ObjCMethodDecl *MD);
+
+    bool IsDeclStmtInForeachHeader(DeclStmt *DS);
+    void CollectBlockDeclRefInfo(BlockExpr *Exp);
+    void GetBlockDeclRefExprs(Stmt *S);
+    void GetInnerBlockDeclRefExprs(Stmt *S,
+                SmallVectorImpl<DeclRefExpr *> &InnerBlockDeclRefs,
+                llvm::SmallPtrSet<const DeclContext *, 8> &InnerContexts);
+
+    // We avoid calling Type::isBlockPointerType(), since it operates on the
+    // canonical type. We only care if the top-level type is a closure pointer.
+    bool isTopLevelBlockPointerType(QualType T) {
+      return isa<BlockPointerType>(T);
+    }
+
+    /// convertBlockPointerToFunctionPointer - Converts a block-pointer type
+    /// to a function pointer type and upon success, returns true; false
+    /// otherwise.
+    bool convertBlockPointerToFunctionPointer(QualType &T) {
+      if (isTopLevelBlockPointerType(T)) {
+        const BlockPointerType *BPT = T->getAs<BlockPointerType>();
+        T = Context->getPointerType(BPT->getPointeeType());
+        return true;
+      }
+      return false;
+    }
+    
+    bool convertObjCTypeToCStyleType(QualType &T);
+    
+    bool needToScanForQualifiers(QualType T);
+    QualType getSuperStructType();
+    QualType getConstantStringStructType();
+    QualType convertFunctionTypeOfBlocks(const FunctionType *FT);
+    bool BufferContainsPPDirectives(const char *startBuf, const char *endBuf);
+    
+    void convertToUnqualifiedObjCType(QualType &T) {
+      if (T->isObjCQualifiedIdType()) {
+        bool isConst = T.isConstQualified();
+        T = isConst ? Context->getObjCIdType().withConst() 
+                    : Context->getObjCIdType();
+      }
+      else if (T->isObjCQualifiedClassType())
+        T = Context->getObjCClassType();
+      else if (T->isObjCObjectPointerType() &&
+               T->getPointeeType()->isObjCQualifiedInterfaceType()) {
+        if (const ObjCObjectPointerType * OBJPT =
+              T->getAsObjCInterfacePointerType()) {
+          const ObjCInterfaceType *IFaceT = OBJPT->getInterfaceType();
+          T = QualType(IFaceT, 0);
+          T = Context->getPointerType(T);
+        }
+     }
+    }
+    
+    // FIXME: This predicate seems like it would be useful to add to ASTContext.
+    bool isObjCType(QualType T) {
+      if (!LangOpts.ObjC1 && !LangOpts.ObjC2)
+        return false;
+
+      QualType OCT = Context->getCanonicalType(T).getUnqualifiedType();
+
+      if (OCT == Context->getCanonicalType(Context->getObjCIdType()) ||
+          OCT == Context->getCanonicalType(Context->getObjCClassType()))
+        return true;
+
+      if (const PointerType *PT = OCT->getAs<PointerType>()) {
+        if (isa<ObjCInterfaceType>(PT->getPointeeType()) ||
+            PT->getPointeeType()->isObjCQualifiedIdType())
+          return true;
+      }
+      return false;
+    }
+    bool PointerTypeTakesAnyBlockArguments(QualType QT);
+    bool PointerTypeTakesAnyObjCQualifiedType(QualType QT);
+    void GetExtentOfArgList(const char *Name, const char *&LParen,
+                            const char *&RParen);
+    
+    void QuoteDoublequotes(std::string &From, std::string &To) {
+      for (unsigned i = 0; i < From.length(); i++) {
+        if (From[i] == '"')
+          To += "\\\"";
+        else
+          To += From[i];
+      }
+    }
+
+    QualType getSimpleFunctionType(QualType result,
+                                   ArrayRef<QualType> args,
+                                   bool variadic = false) {
+      if (result == Context->getObjCInstanceType())
+        result =  Context->getObjCIdType();
+      FunctionProtoType::ExtProtoInfo fpi;
+      fpi.Variadic = variadic;
+      return Context->getFunctionType(result, args, fpi);
+    }
+
+    // Helper function: create a CStyleCastExpr with trivial type source info.
+    CStyleCastExpr* NoTypeInfoCStyleCastExpr(ASTContext *Ctx, QualType Ty,
+                                             CastKind Kind, Expr *E) {
+      TypeSourceInfo *TInfo = Ctx->getTrivialTypeSourceInfo(Ty, SourceLocation());
+      return CStyleCastExpr::Create(*Ctx, Ty, VK_RValue, Kind, E, nullptr,
+                                    TInfo, SourceLocation(), SourceLocation());
+    }
+    
+    bool ImplementationIsNonLazy(const ObjCImplDecl *OD) const {
+      IdentifierInfo* II = &Context->Idents.get("load");
+      Selector LoadSel = Context->Selectors.getSelector(0, &II);
+      return OD->getClassMethod(LoadSel) != nullptr;
+    }
+
+    StringLiteral *getStringLiteral(StringRef Str) {
+      QualType StrType = Context->getConstantArrayType(
+          Context->CharTy, llvm::APInt(32, Str.size() + 1), ArrayType::Normal,
+          0);
+      return StringLiteral::Create(*Context, Str, StringLiteral::Ascii,
+                                   /*Pascal=*/false, StrType, SourceLocation());
+    }
+  };
+  
+}
+
+void RewriteModernObjC::RewriteBlocksInFunctionProtoType(QualType funcType,
+                                                   NamedDecl *D) {
+  if (const FunctionProtoType *fproto
+      = dyn_cast<FunctionProtoType>(funcType.IgnoreParens())) {
+    for (const auto &I : fproto->param_types())
+      if (isTopLevelBlockPointerType(I)) {
+        // All the args are checked/rewritten. Don't call twice!
+        RewriteBlockPointerDecl(D);
+        break;
+      }
+  }
+}
+
+void RewriteModernObjC::CheckFunctionPointerDecl(QualType funcType, NamedDecl *ND) {
+  const PointerType *PT = funcType->getAs<PointerType>();
+  if (PT && PointerTypeTakesAnyBlockArguments(funcType))
+    RewriteBlocksInFunctionProtoType(PT->getPointeeType(), ND);
+}
+
+static bool IsHeaderFile(const std::string &Filename) {
+  std::string::size_type DotPos = Filename.rfind('.');
+
+  if (DotPos == std::string::npos) {
+    // no file extension
+    return false;
+  }
+
+  std::string Ext = std::string(Filename.begin()+DotPos+1, Filename.end());
+  // C header: .h
+  // C++ header: .hh or .H;
+  return Ext == "h" || Ext == "hh" || Ext == "H";
+}
+
+RewriteModernObjC::RewriteModernObjC(std::string inFile, raw_ostream* OS,
+                         DiagnosticsEngine &D, const LangOptions &LOpts,
+                         bool silenceMacroWarn,
+                         bool LineInfo)
+      : Diags(D), LangOpts(LOpts), InFileName(inFile), OutFile(OS),
+        SilenceRewriteMacroWarning(silenceMacroWarn), GenerateLineInfo(LineInfo) {
+  IsHeader = IsHeaderFile(inFile);
+  RewriteFailedDiag = Diags.getCustomDiagID(DiagnosticsEngine::Warning,
+               "rewriting sub-expression within a macro (may not be correct)");
+  // FIXME. This should be an error. But if block is not called, it is OK. And it
+  // may break including some headers.
+  GlobalBlockRewriteFailedDiag = Diags.getCustomDiagID(DiagnosticsEngine::Warning,
+    "rewriting block literal declared in global scope is not implemented");
+          
+  TryFinallyContainsReturnDiag = Diags.getCustomDiagID(
+               DiagnosticsEngine::Warning,
+               "rewriter doesn't support user-specified control flow semantics "
+               "for @try/@finally (code may not execute properly)");
+}
+
+ASTConsumer *clang::CreateModernObjCRewriter(const std::string& InFile,
+                                       raw_ostream* OS,
+                                       DiagnosticsEngine &Diags,
+                                       const LangOptions &LOpts,
+                                       bool SilenceRewriteMacroWarning,
+                                       bool LineInfo) {
+    return new RewriteModernObjC(InFile, OS, Diags, LOpts,
+                                 SilenceRewriteMacroWarning, LineInfo);
+}
+
+void RewriteModernObjC::InitializeCommon(ASTContext &context) {
+  Context = &context;
+  SM = &Context->getSourceManager();
+  TUDecl = Context->getTranslationUnitDecl();
+  MsgSendFunctionDecl = nullptr;
+  MsgSendSuperFunctionDecl = nullptr;
+  MsgSendStretFunctionDecl = nullptr;
+  MsgSendSuperStretFunctionDecl = nullptr;
+  MsgSendFpretFunctionDecl = nullptr;
+  GetClassFunctionDecl = nullptr;
+  GetMetaClassFunctionDecl = nullptr;
+  GetSuperClassFunctionDecl = nullptr;
+  SelGetUidFunctionDecl = nullptr;
+  CFStringFunctionDecl = nullptr;
+  ConstantStringClassReference = nullptr;
+  NSStringRecord = nullptr;
+  CurMethodDef = nullptr;
+  CurFunctionDef = nullptr;
+  GlobalVarDecl = nullptr;
+  GlobalConstructionExp = nullptr;
+  SuperStructDecl = nullptr;
+  ProtocolTypeDecl = nullptr;
+  ConstantStringDecl = nullptr;
+  BcLabelCount = 0;
+  SuperConstructorFunctionDecl = nullptr;
+  NumObjCStringLiterals = 0;
+  PropParentMap = nullptr;
+  CurrentBody = nullptr;
+  DisableReplaceStmt = false;
+  objc_impl_method = false;
+
+  // Get the ID and start/end of the main file.
+  MainFileID = SM->getMainFileID();
+  const llvm::MemoryBuffer *MainBuf = SM->getBuffer(MainFileID);
+  MainFileStart = MainBuf->getBufferStart();
+  MainFileEnd = MainBuf->getBufferEnd();
+
+  Rewrite.setSourceMgr(Context->getSourceManager(), Context->getLangOpts());
+}
+
+//===----------------------------------------------------------------------===//
+// Top Level Driver Code
+//===----------------------------------------------------------------------===//
+
+void RewriteModernObjC::HandleTopLevelSingleDecl(Decl *D) {
+  if (Diags.hasErrorOccurred())
+    return;
+
+  // Two cases: either the decl could be in the main file, or it could be in a
+  // #included file.  If the former, rewrite it now.  If the later, check to see
+  // if we rewrote the #include/#import.
+  SourceLocation Loc = D->getLocation();
+  Loc = SM->getExpansionLoc(Loc);
+
+  // If this is for a builtin, ignore it.
+  if (Loc.isInvalid()) return;
+
+  // Look for built-in declarations that we need to refer during the rewrite.
+  if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
+    RewriteFunctionDecl(FD);
+  } else if (VarDecl *FVD = dyn_cast<VarDecl>(D)) {
+    // declared in <Foundation/NSString.h>
+    if (FVD->getName() == "_NSConstantStringClassReference") {
+      ConstantStringClassReference = FVD;
+      return;
+    }
+  } else if (ObjCCategoryDecl *CD = dyn_cast<ObjCCategoryDecl>(D)) {
+    RewriteCategoryDecl(CD);
+  } else if (ObjCProtocolDecl *PD = dyn_cast<ObjCProtocolDecl>(D)) {
+    if (PD->isThisDeclarationADefinition())
+      RewriteProtocolDecl(PD);
+  } else if (LinkageSpecDecl *LSD = dyn_cast<LinkageSpecDecl>(D)) {
+    // FIXME. This will not work in all situations and leaving it out
+    // is harmless.
+    // RewriteLinkageSpec(LSD);
+    
+    // Recurse into linkage specifications
+    for (DeclContext::decl_iterator DI = LSD->decls_begin(),
+                                 DIEnd = LSD->decls_end();
+         DI != DIEnd; ) {
+      if (ObjCInterfaceDecl *IFace = dyn_cast<ObjCInterfaceDecl>((*DI))) {
+        if (!IFace->isThisDeclarationADefinition()) {
+          SmallVector<Decl *, 8> DG;
+          SourceLocation StartLoc = IFace->getLocStart();
+          do {
+            if (isa<ObjCInterfaceDecl>(*DI) &&
+                !cast<ObjCInterfaceDecl>(*DI)->isThisDeclarationADefinition() &&
+                StartLoc == (*DI)->getLocStart())
+              DG.push_back(*DI);
+            else
+              break;
+            
+            ++DI;
+          } while (DI != DIEnd);
+          RewriteForwardClassDecl(DG);
+          continue;
+        }
+        else {
+          // Keep track of all interface declarations seen.
+          ObjCInterfacesSeen.push_back(IFace);
+          ++DI;
+          continue;
+        }
+      }
+
+      if (ObjCProtocolDecl *Proto = dyn_cast<ObjCProtocolDecl>((*DI))) {
+        if (!Proto->isThisDeclarationADefinition()) {
+          SmallVector<Decl *, 8> DG;
+          SourceLocation StartLoc = Proto->getLocStart();
+          do {
+            if (isa<ObjCProtocolDecl>(*DI) &&
+                !cast<ObjCProtocolDecl>(*DI)->isThisDeclarationADefinition() &&
+                StartLoc == (*DI)->getLocStart())
+              DG.push_back(*DI);
+            else
+              break;
+            
+            ++DI;
+          } while (DI != DIEnd);
+          RewriteForwardProtocolDecl(DG);
+          continue;
+        }
+      }
+      
+      HandleTopLevelSingleDecl(*DI);
+      ++DI;
+    }
+  }
+  // If we have a decl in the main file, see if we should rewrite it.
+  if (SM->isWrittenInMainFile(Loc))
+    return HandleDeclInMainFile(D);
+}
+
+//===----------------------------------------------------------------------===//
+// Syntactic (non-AST) Rewriting Code
+//===----------------------------------------------------------------------===//
+
+void RewriteModernObjC::RewriteInclude() {
+  SourceLocation LocStart = SM->getLocForStartOfFile(MainFileID);
+  StringRef MainBuf = SM->getBufferData(MainFileID);
+  const char *MainBufStart = MainBuf.begin();
+  const char *MainBufEnd = MainBuf.end();
+  size_t ImportLen = strlen("import");
+
+  // Loop over the whole file, looking for includes.
+  for (const char *BufPtr = MainBufStart; BufPtr < MainBufEnd; ++BufPtr) {
+    if (*BufPtr == '#') {
+      if (++BufPtr == MainBufEnd)
+        return;
+      while (*BufPtr == ' ' || *BufPtr == '\t')
+        if (++BufPtr == MainBufEnd)
+          return;
+      if (!strncmp(BufPtr, "import", ImportLen)) {
+        // replace import with include
+        SourceLocation ImportLoc =
+          LocStart.getLocWithOffset(BufPtr-MainBufStart);
+        ReplaceText(ImportLoc, ImportLen, "include");
+        BufPtr += ImportLen;
+      }
+    }
+  }
+}
+
+static void WriteInternalIvarName(const ObjCInterfaceDecl *IDecl,
+                                  ObjCIvarDecl *IvarDecl, std::string &Result) {
+  Result += "OBJC_IVAR_$_";
+  Result += IDecl->getName();
+  Result += "$";
+  Result += IvarDecl->getName();
+}
+
+std::string 
+RewriteModernObjC::getIvarAccessString(ObjCIvarDecl *D) {
+  const ObjCInterfaceDecl *ClassDecl = D->getContainingInterface();
+  
+  // Build name of symbol holding ivar offset.
+  std::string IvarOffsetName;
+  if (D->isBitField())
+    ObjCIvarBitfieldGroupOffset(D, IvarOffsetName);
+  else
+    WriteInternalIvarName(ClassDecl, D, IvarOffsetName);
+  
+  
+  std::string S = "(*(";
+  QualType IvarT = D->getType();
+  if (D->isBitField())
+    IvarT = GetGroupRecordTypeForObjCIvarBitfield(D);
+  
+  if (!isa<TypedefType>(IvarT) && IvarT->isRecordType()) {
+    RecordDecl *RD = IvarT->getAs<RecordType>()->getDecl();
+    RD = RD->getDefinition();
+    if (RD && !RD->getDeclName().getAsIdentifierInfo()) {
+      // decltype(((Foo_IMPL*)0)->bar) *
+      ObjCContainerDecl *CDecl = 
+      dyn_cast<ObjCContainerDecl>(D->getDeclContext());
+      // ivar in class extensions requires special treatment.
+      if (ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CDecl))
+        CDecl = CatDecl->getClassInterface();
+      std::string RecName = CDecl->getName();
+      RecName += "_IMPL";
+      RecordDecl *RD = RecordDecl::Create(*Context, TTK_Struct, TUDecl,
+                                          SourceLocation(), SourceLocation(),
+                                          &Context->Idents.get(RecName.c_str()));
+      QualType PtrStructIMPL = Context->getPointerType(Context->getTagDeclType(RD));
+      unsigned UnsignedIntSize = 
+      static_cast<unsigned>(Context->getTypeSize(Context->UnsignedIntTy));
+      Expr *Zero = IntegerLiteral::Create(*Context,
+                                          llvm::APInt(UnsignedIntSize, 0),
+                                          Context->UnsignedIntTy, SourceLocation());
+      Zero = NoTypeInfoCStyleCastExpr(Context, PtrStructIMPL, CK_BitCast, Zero);
+      ParenExpr *PE = new (Context) ParenExpr(SourceLocation(), SourceLocation(),
+                                              Zero);
+      FieldDecl *FD = FieldDecl::Create(*Context, nullptr, SourceLocation(),
+                                        SourceLocation(),
+                                        &Context->Idents.get(D->getNameAsString()),
+                                        IvarT, nullptr,
+                                        /*BitWidth=*/nullptr, /*Mutable=*/true,
+                                        ICIS_NoInit);
+      MemberExpr *ME = new (Context) MemberExpr(PE, true, FD, SourceLocation(),
+                                                FD->getType(), VK_LValue,
+                                                OK_Ordinary);
+      IvarT = Context->getDecltypeType(ME, ME->getType());
+    }
+  }
+  convertObjCTypeToCStyleType(IvarT);
+  QualType castT = Context->getPointerType(IvarT);
+  std::string TypeString(castT.getAsString(Context->getPrintingPolicy()));
+  S += TypeString;
+  S += ")";
+  
+  // ((char *)self + IVAR_OFFSET_SYMBOL_NAME)
+  S += "((char *)self + ";
+  S += IvarOffsetName;
+  S += "))";
+  if (D->isBitField()) {
+    S += ".";
+    S += D->getNameAsString();
+  }
+  ReferencedIvars[const_cast<ObjCInterfaceDecl *>(ClassDecl)].insert(D);
+  return S;
+}
+
+/// mustSynthesizeSetterGetterMethod - returns true if setter or getter has not
+/// been found in the class implementation. In this case, it must be synthesized.
+static bool mustSynthesizeSetterGetterMethod(ObjCImplementationDecl *IMP,
+                                             ObjCPropertyDecl *PD,
+                                             bool getter) {
+  return getter ? !IMP->getInstanceMethod(PD->getGetterName())
+                : !IMP->getInstanceMethod(PD->getSetterName());
+  
+}
+
+void RewriteModernObjC::RewritePropertyImplDecl(ObjCPropertyImplDecl *PID,
+                                          ObjCImplementationDecl *IMD,
+                                          ObjCCategoryImplDecl *CID) {
+  static bool objcGetPropertyDefined = false;
+  static bool objcSetPropertyDefined = false;
+  SourceLocation startGetterSetterLoc;
+  
+  if (PID->getLocStart().isValid()) {
+    SourceLocation startLoc = PID->getLocStart();
+    InsertText(startLoc, "// ");
+    const char *startBuf = SM->getCharacterData(startLoc);
+    assert((*startBuf == '@') && "bogus @synthesize location");
+    const char *semiBuf = strchr(startBuf, ';');
+    assert((*semiBuf == ';') && "@synthesize: can't find ';'");
+    startGetterSetterLoc = startLoc.getLocWithOffset(semiBuf-startBuf+1);
+  }
+  else
+    startGetterSetterLoc = IMD ? IMD->getLocEnd() : CID->getLocEnd();
+
+  if (PID->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic)
+    return; // FIXME: is this correct?
+
+  // Generate the 'getter' function.
+  ObjCPropertyDecl *PD = PID->getPropertyDecl();
+  ObjCIvarDecl *OID = PID->getPropertyIvarDecl();
+  assert(IMD && OID && "Synthesized ivars must be attached to @implementation");
+
+  unsigned Attributes = PD->getPropertyAttributes();
+  if (mustSynthesizeSetterGetterMethod(IMD, PD, true /*getter*/)) {
+    bool GenGetProperty = !(Attributes & ObjCPropertyDecl::OBJC_PR_nonatomic) &&
+                          (Attributes & (ObjCPropertyDecl::OBJC_PR_retain | 
+                                         ObjCPropertyDecl::OBJC_PR_copy));
+    std::string Getr;
+    if (GenGetProperty && !objcGetPropertyDefined) {
+      objcGetPropertyDefined = true;
+      // FIXME. Is this attribute correct in all cases?
+      Getr = "\nextern \"C\" __declspec(dllimport) "
+            "id objc_getProperty(id, SEL, long, bool);\n";
+    }
+    RewriteObjCMethodDecl(OID->getContainingInterface(),  
+                          PD->getGetterMethodDecl(), Getr);
+    Getr += "{ ";
+    // Synthesize an explicit cast to gain access to the ivar.
+    // See objc-act.c:objc_synthesize_new_getter() for details.
+    if (GenGetProperty) {
+      // return objc_getProperty(self, _cmd, offsetof(ClassDecl, OID), 1)
+      Getr += "typedef ";
+      const FunctionType *FPRetType = nullptr;
+      RewriteTypeIntoString(PD->getGetterMethodDecl()->getReturnType(), Getr,
+                            FPRetType);
+      Getr += " _TYPE";
+      if (FPRetType) {
+        Getr += ")"; // close the precedence "scope" for "*".
+      
+        // Now, emit the argument types (if any).
+        if (const FunctionProtoType *FT = dyn_cast<FunctionProtoType>(FPRetType)){
+          Getr += "(";
+          for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) {
+            if (i) Getr += ", ";
+            std::string ParamStr =
+                FT->getParamType(i).getAsString(Context->getPrintingPolicy());
+            Getr += ParamStr;
+          }
+          if (FT->isVariadic()) {
+            if (FT->getNumParams())
+              Getr += ", ";
+            Getr += "...";
+          }
+          Getr += ")";
+        } else
+          Getr += "()";
+      }
+      Getr += ";\n";
+      Getr += "return (_TYPE)";
+      Getr += "objc_getProperty(self, _cmd, ";
+      RewriteIvarOffsetComputation(OID, Getr);
+      Getr += ", 1)";
+    }
+    else
+      Getr += "return " + getIvarAccessString(OID);
+    Getr += "; }";
+    InsertText(startGetterSetterLoc, Getr);
+  }
+  
+  if (PD->isReadOnly() || 
+      !mustSynthesizeSetterGetterMethod(IMD, PD, false /*setter*/))
+    return;
+
+  // Generate the 'setter' function.
+  std::string Setr;
+  bool GenSetProperty = Attributes & (ObjCPropertyDecl::OBJC_PR_retain | 
+                                      ObjCPropertyDecl::OBJC_PR_copy);
+  if (GenSetProperty && !objcSetPropertyDefined) {
+    objcSetPropertyDefined = true;
+    // FIXME. Is this attribute correct in all cases?
+    Setr = "\nextern \"C\" __declspec(dllimport) "
+    "void objc_setProperty (id, SEL, long, id, bool, bool);\n";
+  }
+  
+  RewriteObjCMethodDecl(OID->getContainingInterface(), 
+                        PD->getSetterMethodDecl(), Setr);
+  Setr += "{ ";
+  // Synthesize an explicit cast to initialize the ivar.
+  // See objc-act.c:objc_synthesize_new_setter() for details.
+  if (GenSetProperty) {
+    Setr += "objc_setProperty (self, _cmd, ";
+    RewriteIvarOffsetComputation(OID, Setr);
+    Setr += ", (id)";
+    Setr += PD->getName();
+    Setr += ", ";
+    if (Attributes & ObjCPropertyDecl::OBJC_PR_nonatomic)
+      Setr += "0, ";
+    else
+      Setr += "1, ";
+    if (Attributes & ObjCPropertyDecl::OBJC_PR_copy)
+      Setr += "1)";
+    else
+      Setr += "0)";
+  }
+  else {
+    Setr += getIvarAccessString(OID) + " = ";
+    Setr += PD->getName();
+  }
+  Setr += "; }\n";
+  InsertText(startGetterSetterLoc, Setr);
+}
+
+static void RewriteOneForwardClassDecl(ObjCInterfaceDecl *ForwardDecl,
+                                       std::string &typedefString) {
+  typedefString += "\n#ifndef _REWRITER_typedef_";
+  typedefString += ForwardDecl->getNameAsString();
+  typedefString += "\n";
+  typedefString += "#define _REWRITER_typedef_";
+  typedefString += ForwardDecl->getNameAsString();
+  typedefString += "\n";
+  typedefString += "typedef struct objc_object ";
+  typedefString += ForwardDecl->getNameAsString();
+  // typedef struct { } _objc_exc_Classname;
+  typedefString += ";\ntypedef struct {} _objc_exc_";
+  typedefString += ForwardDecl->getNameAsString();
+  typedefString += ";\n#endif\n";
+}
+
+void RewriteModernObjC::RewriteForwardClassEpilogue(ObjCInterfaceDecl *ClassDecl,
+                                              const std::string &typedefString) {
+    SourceLocation startLoc = ClassDecl->getLocStart();
+    const char *startBuf = SM->getCharacterData(startLoc);
+    const char *semiPtr = strchr(startBuf, ';'); 
+    // Replace the @class with typedefs corresponding to the classes.
+    ReplaceText(startLoc, semiPtr-startBuf+1, typedefString);  
+}
+
+void RewriteModernObjC::RewriteForwardClassDecl(DeclGroupRef D) {
+  std::string typedefString;
+  for (DeclGroupRef::iterator I = D.begin(), E = D.end(); I != E; ++I) {
+    if (ObjCInterfaceDecl *ForwardDecl = dyn_cast<ObjCInterfaceDecl>(*I)) {
+      if (I == D.begin()) {
+        // Translate to typedef's that forward reference structs with the same name
+        // as the class. As a convenience, we include the original declaration
+        // as a comment.
+        typedefString += "// @class ";
+        typedefString += ForwardDecl->getNameAsString();
+        typedefString += ";";
+      }
+      RewriteOneForwardClassDecl(ForwardDecl, typedefString);
+    }
+    else
+      HandleTopLevelSingleDecl(*I);
+  }
+  DeclGroupRef::iterator I = D.begin();
+  RewriteForwardClassEpilogue(cast<ObjCInterfaceDecl>(*I), typedefString);
+}
+
+void RewriteModernObjC::RewriteForwardClassDecl(
+                                const SmallVectorImpl<Decl *> &D) {
+  std::string typedefString;
+  for (unsigned i = 0; i < D.size(); i++) {
+    ObjCInterfaceDecl *ForwardDecl = cast<ObjCInterfaceDecl>(D[i]);
+    if (i == 0) {
+      typedefString += "// @class ";
+      typedefString += ForwardDecl->getNameAsString();
+      typedefString += ";";
+    }
+    RewriteOneForwardClassDecl(ForwardDecl, typedefString);
+  }
+  RewriteForwardClassEpilogue(cast<ObjCInterfaceDecl>(D[0]), typedefString);
+}
+
+void RewriteModernObjC::RewriteMethodDeclaration(ObjCMethodDecl *Method) {
+  // When method is a synthesized one, such as a getter/setter there is
+  // nothing to rewrite.
+  if (Method->isImplicit())
+    return;
+  SourceLocation LocStart = Method->getLocStart();
+  SourceLocation LocEnd = Method->getLocEnd();
+
+  if (SM->getExpansionLineNumber(LocEnd) >
+      SM->getExpansionLineNumber(LocStart)) {
+    InsertText(LocStart, "#if 0\n");
+    ReplaceText(LocEnd, 1, ";\n#endif\n");
+  } else {
+    InsertText(LocStart, "// ");
+  }
+}
+
+void RewriteModernObjC::RewriteProperty(ObjCPropertyDecl *prop) {
+  SourceLocation Loc = prop->getAtLoc();
+
+  ReplaceText(Loc, 0, "// ");
+  // FIXME: handle properties that are declared across multiple lines.
+}
+
+void RewriteModernObjC::RewriteCategoryDecl(ObjCCategoryDecl *CatDecl) {
+  SourceLocation LocStart = CatDecl->getLocStart();
+
+  // FIXME: handle category headers that are declared across multiple lines.
+  if (CatDecl->getIvarRBraceLoc().isValid()) {
+    ReplaceText(LocStart, 1, "/** ");
+    ReplaceText(CatDecl->getIvarRBraceLoc(), 1, "**/ ");
+  }
+  else {
+    ReplaceText(LocStart, 0, "// ");
+  }
+  
+  for (auto *I : CatDecl->properties())
+    RewriteProperty(I);
+  
+  for (auto *I : CatDecl->instance_methods())
+    RewriteMethodDeclaration(I);
+  for (auto *I : CatDecl->class_methods())
+    RewriteMethodDeclaration(I);
+
+  // Lastly, comment out the @end.
+  ReplaceText(CatDecl->getAtEndRange().getBegin(), 
+              strlen("@end"), "/* @end */\n");
+}
+
+void RewriteModernObjC::RewriteProtocolDecl(ObjCProtocolDecl *PDecl) {
+  SourceLocation LocStart = PDecl->getLocStart();
+  assert(PDecl->isThisDeclarationADefinition());
+  
+  // FIXME: handle protocol headers that are declared across multiple lines.
+  ReplaceText(LocStart, 0, "// ");
+
+  for (auto *I : PDecl->instance_methods())
+    RewriteMethodDeclaration(I);
+  for (auto *I : PDecl->class_methods())
+    RewriteMethodDeclaration(I);
+  for (auto *I : PDecl->properties())
+    RewriteProperty(I);
+  
+  // Lastly, comment out the @end.
+  SourceLocation LocEnd = PDecl->getAtEndRange().getBegin();
+  ReplaceText(LocEnd, strlen("@end"), "/* @end */\n");
+
+  // Must comment out @optional/@required
+  const char *startBuf = SM->getCharacterData(LocStart);
+  const char *endBuf = SM->getCharacterData(LocEnd);
+  for (const char *p = startBuf; p < endBuf; p++) {
+    if (*p == '@' && !strncmp(p+1, "optional", strlen("optional"))) {
+      SourceLocation OptionalLoc = LocStart.getLocWithOffset(p-startBuf);
+      ReplaceText(OptionalLoc, strlen("@optional"), "/* @optional */");
+
+    }
+    else if (*p == '@' && !strncmp(p+1, "required", strlen("required"))) {
+      SourceLocation OptionalLoc = LocStart.getLocWithOffset(p-startBuf);
+      ReplaceText(OptionalLoc, strlen("@required"), "/* @required */");
+
+    }
+  }
+}
+
+void RewriteModernObjC::RewriteForwardProtocolDecl(DeclGroupRef D) {
+  SourceLocation LocStart = (*D.begin())->getLocStart();
+  if (LocStart.isInvalid())
+    llvm_unreachable("Invalid SourceLocation");
+  // FIXME: handle forward protocol that are declared across multiple lines.
+  ReplaceText(LocStart, 0, "// ");
+}
+
+void 
+RewriteModernObjC::RewriteForwardProtocolDecl(const SmallVectorImpl<Decl *> &DG) {
+  SourceLocation LocStart = DG[0]->getLocStart();
+  if (LocStart.isInvalid())
+    llvm_unreachable("Invalid SourceLocation");
+  // FIXME: handle forward protocol that are declared across multiple lines.
+  ReplaceText(LocStart, 0, "// ");
+}
+
+void 
+RewriteModernObjC::RewriteLinkageSpec(LinkageSpecDecl *LSD) {
+  SourceLocation LocStart = LSD->getExternLoc();
+  if (LocStart.isInvalid())
+    llvm_unreachable("Invalid extern SourceLocation");
+  
+  ReplaceText(LocStart, 0, "// ");
+  if (!LSD->hasBraces())
+    return;
+  // FIXME. We don't rewrite well if '{' is not on same line as 'extern'.
+  SourceLocation LocRBrace = LSD->getRBraceLoc();
+  if (LocRBrace.isInvalid())
+    llvm_unreachable("Invalid rbrace SourceLocation");
+  ReplaceText(LocRBrace, 0, "// ");
+}
+
+void RewriteModernObjC::RewriteTypeIntoString(QualType T, std::string &ResultStr,
+                                        const FunctionType *&FPRetType) {
+  if (T->isObjCQualifiedIdType())
+    ResultStr += "id";
+  else if (T->isFunctionPointerType() ||
+           T->isBlockPointerType()) {
+    // needs special handling, since pointer-to-functions have special
+    // syntax (where a decaration models use).
+    QualType retType = T;
+    QualType PointeeTy;
+    if (const PointerType* PT = retType->getAs<PointerType>())
+      PointeeTy = PT->getPointeeType();
+    else if (const BlockPointerType *BPT = retType->getAs<BlockPointerType>())
+      PointeeTy = BPT->getPointeeType();
+    if ((FPRetType = PointeeTy->getAs<FunctionType>())) {
+      ResultStr +=
+          FPRetType->getReturnType().getAsString(Context->getPrintingPolicy());
+      ResultStr += "(*";
+    }
+  } else
+    ResultStr += T.getAsString(Context->getPrintingPolicy());
+}
+
+void RewriteModernObjC::RewriteObjCMethodDecl(const ObjCInterfaceDecl *IDecl,
+                                        ObjCMethodDecl *OMD,
+                                        std::string &ResultStr) {
+  //fprintf(stderr,"In RewriteObjCMethodDecl\n");
+  const FunctionType *FPRetType = nullptr;
+  ResultStr += "\nstatic ";
+  RewriteTypeIntoString(OMD->getReturnType(), ResultStr, FPRetType);
+  ResultStr += " ";
+
+  // Unique method name
+  std::string NameStr;
+
+  if (OMD->isInstanceMethod())
+    NameStr += "_I_";
+  else
+    NameStr += "_C_";
+
+  NameStr += IDecl->getNameAsString();
+  NameStr += "_";
+
+  if (ObjCCategoryImplDecl *CID =
+      dyn_cast<ObjCCategoryImplDecl>(OMD->getDeclContext())) {
+    NameStr += CID->getNameAsString();
+    NameStr += "_";
+  }
+  // Append selector names, replacing ':' with '_'
+  {
+    std::string selString = OMD->getSelector().getAsString();
+    int len = selString.size();
+    for (int i = 0; i < len; i++)
+      if (selString[i] == ':')
+        selString[i] = '_';
+    NameStr += selString;
+  }
+  // Remember this name for metadata emission
+  MethodInternalNames[OMD] = NameStr;
+  ResultStr += NameStr;
+
+  // Rewrite arguments
+  ResultStr += "(";
+
+  // invisible arguments
+  if (OMD->isInstanceMethod()) {
+    QualType selfTy = Context->getObjCInterfaceType(IDecl);
+    selfTy = Context->getPointerType(selfTy);
+    if (!LangOpts.MicrosoftExt) {
+      if (ObjCSynthesizedStructs.count(const_cast<ObjCInterfaceDecl*>(IDecl)))
+        ResultStr += "struct ";
+    }
+    // When rewriting for Microsoft, explicitly omit the structure name.
+    ResultStr += IDecl->getNameAsString();
+    ResultStr += " *";
+  }
+  else
+    ResultStr += Context->getObjCClassType().getAsString(
+      Context->getPrintingPolicy());
+
+  ResultStr += " self, ";
+  ResultStr += Context->getObjCSelType().getAsString(Context->getPrintingPolicy());
+  ResultStr += " _cmd";
+
+  // Method arguments.
+  for (const auto *PDecl : OMD->params()) {
+    ResultStr += ", ";
+    if (PDecl->getType()->isObjCQualifiedIdType()) {
+      ResultStr += "id ";
+      ResultStr += PDecl->getNameAsString();
+    } else {
+      std::string Name = PDecl->getNameAsString();
+      QualType QT = PDecl->getType();
+      // Make sure we convert "t (^)(...)" to "t (*)(...)".
+      (void)convertBlockPointerToFunctionPointer(QT);
+      QT.getAsStringInternal(Name, Context->getPrintingPolicy());
+      ResultStr += Name;
+    }
+  }
+  if (OMD->isVariadic())
+    ResultStr += ", ...";
+  ResultStr += ") ";
+
+  if (FPRetType) {
+    ResultStr += ")"; // close the precedence "scope" for "*".
+
+    // Now, emit the argument types (if any).
+    if (const FunctionProtoType *FT = dyn_cast<FunctionProtoType>(FPRetType)) {
+      ResultStr += "(";
+      for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) {
+        if (i) ResultStr += ", ";
+        std::string ParamStr =
+            FT->getParamType(i).getAsString(Context->getPrintingPolicy());
+        ResultStr += ParamStr;
+      }
+      if (FT->isVariadic()) {
+        if (FT->getNumParams())
+          ResultStr += ", ";
+        ResultStr += "...";
+      }
+      ResultStr += ")";
+    } else {
+      ResultStr += "()";
+    }
+  }
+}
+void RewriteModernObjC::RewriteImplementationDecl(Decl *OID) {
+  ObjCImplementationDecl *IMD = dyn_cast<ObjCImplementationDecl>(OID);
+  ObjCCategoryImplDecl *CID = dyn_cast<ObjCCategoryImplDecl>(OID);
+
+  if (IMD) {
+    if (IMD->getIvarRBraceLoc().isValid()) {
+      ReplaceText(IMD->getLocStart(), 1, "/** ");
+      ReplaceText(IMD->getIvarRBraceLoc(), 1, "**/ ");
+    }
+    else {
+      InsertText(IMD->getLocStart(), "// ");
+    }
+  }
+  else
+    InsertText(CID->getLocStart(), "// ");
+
+  for (auto *OMD : IMD ? IMD->instance_methods() : CID->instance_methods()) {
+    std::string ResultStr;
+    RewriteObjCMethodDecl(OMD->getClassInterface(), OMD, ResultStr);
+    SourceLocation LocStart = OMD->getLocStart();
+    SourceLocation LocEnd = OMD->getCompoundBody()->getLocStart();
+
+    const char *startBuf = SM->getCharacterData(LocStart);
+    const char *endBuf = SM->getCharacterData(LocEnd);
+    ReplaceText(LocStart, endBuf-startBuf, ResultStr);
+  }
+
+  for (auto *OMD : IMD ? IMD->class_methods() : CID->class_methods()) {
+    std::string ResultStr;
+    RewriteObjCMethodDecl(OMD->getClassInterface(), OMD, ResultStr);
+    SourceLocation LocStart = OMD->getLocStart();
+    SourceLocation LocEnd = OMD->getCompoundBody()->getLocStart();
+
+    const char *startBuf = SM->getCharacterData(LocStart);
+    const char *endBuf = SM->getCharacterData(LocEnd);
+    ReplaceText(LocStart, endBuf-startBuf, ResultStr);
+  }
+  for (auto *I : IMD ? IMD->property_impls() : CID->property_impls())
+    RewritePropertyImplDecl(I, IMD, CID);
+
+  InsertText(IMD ? IMD->getLocEnd() : CID->getLocEnd(), "// ");
+}
+
+void RewriteModernObjC::RewriteInterfaceDecl(ObjCInterfaceDecl *ClassDecl) {
+  // Do not synthesize more than once.
+  if (ObjCSynthesizedStructs.count(ClassDecl))
+    return;
+  // Make sure super class's are written before current class is written.
+  ObjCInterfaceDecl *SuperClass = ClassDecl->getSuperClass();
+  while (SuperClass) {
+    RewriteInterfaceDecl(SuperClass);
+    SuperClass = SuperClass->getSuperClass();
+  }
+  std::string ResultStr;
+  if (!ObjCWrittenInterfaces.count(ClassDecl->getCanonicalDecl())) {
+    // we haven't seen a forward decl - generate a typedef.
+    RewriteOneForwardClassDecl(ClassDecl, ResultStr);
+    RewriteIvarOffsetSymbols(ClassDecl, ResultStr);
+    
+    RewriteObjCInternalStruct(ClassDecl, ResultStr);
+    // Mark this typedef as having been written into its c++ equivalent.
+    ObjCWrittenInterfaces.insert(ClassDecl->getCanonicalDecl());
+  
+    for (auto *I : ClassDecl->properties())
+      RewriteProperty(I);
+    for (auto *I : ClassDecl->instance_methods())
+      RewriteMethodDeclaration(I);
+    for (auto *I : ClassDecl->class_methods())
+      RewriteMethodDeclaration(I);
+
+    // Lastly, comment out the @end.
+    ReplaceText(ClassDecl->getAtEndRange().getBegin(), strlen("@end"), 
+                "/* @end */\n");
+  }
+}
+
+Stmt *RewriteModernObjC::RewritePropertyOrImplicitSetter(PseudoObjectExpr *PseudoOp) {
+  SourceRange OldRange = PseudoOp->getSourceRange();
+
+  // We just magically know some things about the structure of this
+  // expression.
+  ObjCMessageExpr *OldMsg =
+    cast<ObjCMessageExpr>(PseudoOp->getSemanticExpr(
+                            PseudoOp->getNumSemanticExprs() - 1));
+
+  // Because the rewriter doesn't allow us to rewrite rewritten code,
+  // we need to suppress rewriting the sub-statements.
+  Expr *Base;
+  SmallVector<Expr*, 2> Args;
+  {
+    DisableReplaceStmtScope S(*this);
+
+    // Rebuild the base expression if we have one.
+    Base = nullptr;
+    if (OldMsg->getReceiverKind() == ObjCMessageExpr::Instance) {
+      Base = OldMsg->getInstanceReceiver();
+      Base = cast<OpaqueValueExpr>(Base)->getSourceExpr();
+      Base = cast<Expr>(RewriteFunctionBodyOrGlobalInitializer(Base));
+    }
+  
+    unsigned numArgs = OldMsg->getNumArgs();
+    for (unsigned i = 0; i < numArgs; i++) {
+      Expr *Arg = OldMsg->getArg(i);
+      if (isa<OpaqueValueExpr>(Arg))
+        Arg = cast<OpaqueValueExpr>(Arg)->getSourceExpr();
+      Arg = cast<Expr>(RewriteFunctionBodyOrGlobalInitializer(Arg));
+      Args.push_back(Arg);
+    }
+  }
+
+  // TODO: avoid this copy.
+  SmallVector<SourceLocation, 1> SelLocs;
+  OldMsg->getSelectorLocs(SelLocs);
+
+  ObjCMessageExpr *NewMsg = nullptr;
+  switch (OldMsg->getReceiverKind()) {
+  case ObjCMessageExpr::Class:
+    NewMsg = ObjCMessageExpr::Create(*Context, OldMsg->getType(),
+                                     OldMsg->getValueKind(),
+                                     OldMsg->getLeftLoc(),
+                                     OldMsg->getClassReceiverTypeInfo(),
+                                     OldMsg->getSelector(),
+                                     SelLocs,
+                                     OldMsg->getMethodDecl(),
+                                     Args,
+                                     OldMsg->getRightLoc(),
+                                     OldMsg->isImplicit());
+    break;
+
+  case ObjCMessageExpr::Instance:
+    NewMsg = ObjCMessageExpr::Create(*Context, OldMsg->getType(),
+                                     OldMsg->getValueKind(),
+                                     OldMsg->getLeftLoc(),
+                                     Base,
+                                     OldMsg->getSelector(),
+                                     SelLocs,
+                                     OldMsg->getMethodDecl(),
+                                     Args,
+                                     OldMsg->getRightLoc(),
+                                     OldMsg->isImplicit());
+    break;
+
+  case ObjCMessageExpr::SuperClass:
+  case ObjCMessageExpr::SuperInstance:
+    NewMsg = ObjCMessageExpr::Create(*Context, OldMsg->getType(),
+                                     OldMsg->getValueKind(),
+                                     OldMsg->getLeftLoc(),
+                                     OldMsg->getSuperLoc(),
+                 OldMsg->getReceiverKind() == ObjCMessageExpr::SuperInstance,
+                                     OldMsg->getSuperType(),
+                                     OldMsg->getSelector(),
+                                     SelLocs,
+                                     OldMsg->getMethodDecl(),
+                                     Args,
+                                     OldMsg->getRightLoc(),
+                                     OldMsg->isImplicit());
+    break;
+  }
+
+  Stmt *Replacement = SynthMessageExpr(NewMsg);
+  ReplaceStmtWithRange(PseudoOp, Replacement, OldRange);
+  return Replacement;
+}
+
+Stmt *RewriteModernObjC::RewritePropertyOrImplicitGetter(PseudoObjectExpr *PseudoOp) {
+  SourceRange OldRange = PseudoOp->getSourceRange();
+
+  // We just magically know some things about the structure of this
+  // expression.
+  ObjCMessageExpr *OldMsg =
+    cast<ObjCMessageExpr>(PseudoOp->getResultExpr()->IgnoreImplicit());
+
+  // Because the rewriter doesn't allow us to rewrite rewritten code,
+  // we need to suppress rewriting the sub-statements.
+  Expr *Base = nullptr;
+  SmallVector<Expr*, 1> Args;
+  {
+    DisableReplaceStmtScope S(*this);
+    // Rebuild the base expression if we have one.
+    if (OldMsg->getReceiverKind() == ObjCMessageExpr::Instance) {
+      Base = OldMsg->getInstanceReceiver();
+      Base = cast<OpaqueValueExpr>(Base)->getSourceExpr();
+      Base = cast<Expr>(RewriteFunctionBodyOrGlobalInitializer(Base));
+    }
+    unsigned numArgs = OldMsg->getNumArgs();
+    for (unsigned i = 0; i < numArgs; i++) {
+      Expr *Arg = OldMsg->getArg(i);
+      if (isa<OpaqueValueExpr>(Arg))
+        Arg = cast<OpaqueValueExpr>(Arg)->getSourceExpr();
+      Arg = cast<Expr>(RewriteFunctionBodyOrGlobalInitializer(Arg));
+      Args.push_back(Arg);
+    }
+  }
+
+  // Intentionally empty.
+  SmallVector<SourceLocation, 1> SelLocs;
+
+  ObjCMessageExpr *NewMsg = nullptr;
+  switch (OldMsg->getReceiverKind()) {
+  case ObjCMessageExpr::Class:
+    NewMsg = ObjCMessageExpr::Create(*Context, OldMsg->getType(),
+                                     OldMsg->getValueKind(),
+                                     OldMsg->getLeftLoc(),
+                                     OldMsg->getClassReceiverTypeInfo(),
+                                     OldMsg->getSelector(),
+                                     SelLocs,
+                                     OldMsg->getMethodDecl(),
+                                     Args,
+                                     OldMsg->getRightLoc(),
+                                     OldMsg->isImplicit());
+    break;
+
+  case ObjCMessageExpr::Instance:
+    NewMsg = ObjCMessageExpr::Create(*Context, OldMsg->getType(),
+                                     OldMsg->getValueKind(),
+                                     OldMsg->getLeftLoc(),
+                                     Base,
+                                     OldMsg->getSelector(),
+                                     SelLocs,
+                                     OldMsg->getMethodDecl(),
+                                     Args,
+                                     OldMsg->getRightLoc(),
+                                     OldMsg->isImplicit());
+    break;
+
+  case ObjCMessageExpr::SuperClass:
+  case ObjCMessageExpr::SuperInstance:
+    NewMsg = ObjCMessageExpr::Create(*Context, OldMsg->getType(),
+                                     OldMsg->getValueKind(),
+                                     OldMsg->getLeftLoc(),
+                                     OldMsg->getSuperLoc(),
+                 OldMsg->getReceiverKind() == ObjCMessageExpr::SuperInstance,
+                                     OldMsg->getSuperType(),
+                                     OldMsg->getSelector(),
+                                     SelLocs,
+                                     OldMsg->getMethodDecl(),
+                                     Args,
+                                     OldMsg->getRightLoc(),
+                                     OldMsg->isImplicit());
+    break;
+  }
+
+  Stmt *Replacement = SynthMessageExpr(NewMsg);
+  ReplaceStmtWithRange(PseudoOp, Replacement, OldRange);
+  return Replacement;
+}
+
+/// SynthCountByEnumWithState - To print:
+/// ((NSUInteger (*)
+///  (id, SEL, struct __objcFastEnumerationState *, id *, NSUInteger))
+///  (void *)objc_msgSend)((id)l_collection,
+///                        sel_registerName(
+///                          "countByEnumeratingWithState:objects:count:"),
+///                        &enumState,
+///                        (id *)__rw_items, (NSUInteger)16)
+///
+void RewriteModernObjC::SynthCountByEnumWithState(std::string &buf) {
+  buf += "((_WIN_NSUInteger (*) (id, SEL, struct __objcFastEnumerationState *, "
+  "id *, _WIN_NSUInteger))(void *)objc_msgSend)";
+  buf += "\n\t\t";
+  buf += "((id)l_collection,\n\t\t";
+  buf += "sel_registerName(\"countByEnumeratingWithState:objects:count:\"),";
+  buf += "\n\t\t";
+  buf += "&enumState, "
+         "(id *)__rw_items, (_WIN_NSUInteger)16)";
+}
+
+/// RewriteBreakStmt - Rewrite for a break-stmt inside an ObjC2's foreach
+/// statement to exit to its outer synthesized loop.
+///
+Stmt *RewriteModernObjC::RewriteBreakStmt(BreakStmt *S) {
+  if (Stmts.empty() || !isa<ObjCForCollectionStmt>(Stmts.back()))
+    return S;
+  // replace break with goto __break_label
+  std::string buf;
+
+  SourceLocation startLoc = S->getLocStart();
+  buf = "goto __break_label_";
+  buf += utostr(ObjCBcLabelNo.back());
+  ReplaceText(startLoc, strlen("break"), buf);
+
+  return nullptr;
+}
+
+void RewriteModernObjC::ConvertSourceLocationToLineDirective(
+                                          SourceLocation Loc,
+                                          std::string &LineString) {
+  if (Loc.isFileID() && GenerateLineInfo) {
+    LineString += "\n#line ";
+    PresumedLoc PLoc = SM->getPresumedLoc(Loc);
+    LineString += utostr(PLoc.getLine());
+    LineString += " \"";
+    LineString += Lexer::Stringify(PLoc.getFilename());
+    LineString += "\"\n";
+  }
+}
+
+/// RewriteContinueStmt - Rewrite for a continue-stmt inside an ObjC2's foreach
+/// statement to continue with its inner synthesized loop.
+///
+Stmt *RewriteModernObjC::RewriteContinueStmt(ContinueStmt *S) {
+  if (Stmts.empty() || !isa<ObjCForCollectionStmt>(Stmts.back()))
+    return S;
+  // replace continue with goto __continue_label
+  std::string buf;
+
+  SourceLocation startLoc = S->getLocStart();
+  buf = "goto __continue_label_";
+  buf += utostr(ObjCBcLabelNo.back());
+  ReplaceText(startLoc, strlen("continue"), buf);
+
+  return nullptr;
+}
+
+/// RewriteObjCForCollectionStmt - Rewriter for ObjC2's foreach statement.
+///  It rewrites:
+/// for ( type elem in collection) { stmts; }
+
+/// Into:
+/// {
+///   type elem;
+///   struct __objcFastEnumerationState enumState = { 0 };
+///   id __rw_items[16];
+///   id l_collection = (id)collection;
+///   NSUInteger limit = [l_collection countByEnumeratingWithState:&enumState
+///                                       objects:__rw_items count:16];
+/// if (limit) {
+///   unsigned long startMutations = *enumState.mutationsPtr;
+///   do {
+///        unsigned long counter = 0;
+///        do {
+///             if (startMutations != *enumState.mutationsPtr)
+///               objc_enumerationMutation(l_collection);
+///             elem = (type)enumState.itemsPtr[counter++];
+///             stmts;
+///             __continue_label: ;
+///        } while (counter < limit);
+///   } while ((limit = [l_collection countByEnumeratingWithState:&enumState
+///                                  objects:__rw_items count:16]));
+///   elem = nil;
+///   __break_label: ;
+///  }
+///  else
+///       elem = nil;
+///  }
+///
+Stmt *RewriteModernObjC::RewriteObjCForCollectionStmt(ObjCForCollectionStmt *S,
+                                                SourceLocation OrigEnd) {
+  assert(!Stmts.empty() && "ObjCForCollectionStmt - Statement stack empty");
+  assert(isa<ObjCForCollectionStmt>(Stmts.back()) &&
+         "ObjCForCollectionStmt Statement stack mismatch");
+  assert(!ObjCBcLabelNo.empty() &&
+         "ObjCForCollectionStmt - Label No stack empty");
+
+  SourceLocation startLoc = S->getLocStart();
+  const char *startBuf = SM->getCharacterData(startLoc);
+  StringRef elementName;
+  std::string elementTypeAsString;
+  std::string buf;
+  // line directive first.
+  SourceLocation ForEachLoc = S->getForLoc();
+  ConvertSourceLocationToLineDirective(ForEachLoc, buf);
+  buf += "{\n\t";
+  if (DeclStmt *DS = dyn_cast<DeclStmt>(S->getElement())) {
+    // type elem;
+    NamedDecl* D = cast<NamedDecl>(DS->getSingleDecl());
+    QualType ElementType = cast<ValueDecl>(D)->getType();
+    if (ElementType->isObjCQualifiedIdType() ||
+        ElementType->isObjCQualifiedInterfaceType())
+      // Simply use 'id' for all qualified types.
+      elementTypeAsString = "id";
+    else
+      elementTypeAsString = ElementType.getAsString(Context->getPrintingPolicy());
+    buf += elementTypeAsString;
+    buf += " ";
+    elementName = D->getName();
+    buf += elementName;
+    buf += ";\n\t";
+  }
+  else {
+    DeclRefExpr *DR = cast<DeclRefExpr>(S->getElement());
+    elementName = DR->getDecl()->getName();
+    ValueDecl *VD = cast<ValueDecl>(DR->getDecl());
+    if (VD->getType()->isObjCQualifiedIdType() ||
+        VD->getType()->isObjCQualifiedInterfaceType())
+      // Simply use 'id' for all qualified types.
+      elementTypeAsString = "id";
+    else
+      elementTypeAsString = VD->getType().getAsString(Context->getPrintingPolicy());
+  }
+
+  // struct __objcFastEnumerationState enumState = { 0 };
+  buf += "struct __objcFastEnumerationState enumState = { 0 };\n\t";
+  // id __rw_items[16];
+  buf += "id __rw_items[16];\n\t";
+  // id l_collection = (id)
+  buf += "id l_collection = (id)";
+  // Find start location of 'collection' the hard way!
+  const char *startCollectionBuf = startBuf;
+  startCollectionBuf += 3;  // skip 'for'
+  startCollectionBuf = strchr(startCollectionBuf, '(');
+  startCollectionBuf++; // skip '('
+  // find 'in' and skip it.
+  while (*startCollectionBuf != ' ' ||
+         *(startCollectionBuf+1) != 'i' || *(startCollectionBuf+2) != 'n' ||
+         (*(startCollectionBuf+3) != ' ' &&
+          *(startCollectionBuf+3) != '[' && *(startCollectionBuf+3) != '('))
+    startCollectionBuf++;
+  startCollectionBuf += 3;
+
+  // Replace: "for (type element in" with string constructed thus far.
+  ReplaceText(startLoc, startCollectionBuf - startBuf, buf);
+  // Replace ')' in for '(' type elem in collection ')' with ';'
+  SourceLocation rightParenLoc = S->getRParenLoc();
+  const char *rparenBuf = SM->getCharacterData(rightParenLoc);
+  SourceLocation lparenLoc = startLoc.getLocWithOffset(rparenBuf-startBuf);
+  buf = ";\n\t";
+
+  // unsigned long limit = [l_collection countByEnumeratingWithState:&enumState
+  //                                   objects:__rw_items count:16];
+  // which is synthesized into:
+  // NSUInteger limit =
+  // ((NSUInteger (*)
+  //  (id, SEL, struct __objcFastEnumerationState *, id *, NSUInteger))
+  //  (void *)objc_msgSend)((id)l_collection,
+  //                        sel_registerName(
+  //                          "countByEnumeratingWithState:objects:count:"),
+  //                        (struct __objcFastEnumerationState *)&state,
+  //                        (id *)__rw_items, (NSUInteger)16);
+  buf += "_WIN_NSUInteger limit =\n\t\t";
+  SynthCountByEnumWithState(buf);
+  buf += ";\n\t";
+  /// if (limit) {
+  ///   unsigned long startMutations = *enumState.mutationsPtr;
+  ///   do {
+  ///        unsigned long counter = 0;
+  ///        do {
+  ///             if (startMutations != *enumState.mutationsPtr)
+  ///               objc_enumerationMutation(l_collection);
+  ///             elem = (type)enumState.itemsPtr[counter++];
+  buf += "if (limit) {\n\t";
+  buf += "unsigned long startMutations = *enumState.mutationsPtr;\n\t";
+  buf += "do {\n\t\t";
+  buf += "unsigned long counter = 0;\n\t\t";
+  buf += "do {\n\t\t\t";
+  buf += "if (startMutations != *enumState.mutationsPtr)\n\t\t\t\t";
+  buf += "objc_enumerationMutation(l_collection);\n\t\t\t";
+  buf += elementName;
+  buf += " = (";
+  buf += elementTypeAsString;
+  buf += ")enumState.itemsPtr[counter++];";
+  // Replace ')' in for '(' type elem in collection ')' with all of these.
+  ReplaceText(lparenLoc, 1, buf);
+
+  ///            __continue_label: ;
+  ///        } while (counter < limit);
+  ///   } while ((limit = [l_collection countByEnumeratingWithState:&enumState
+  ///                                  objects:__rw_items count:16]));
+  ///   elem = nil;
+  ///   __break_label: ;
+  ///  }
+  ///  else
+  ///       elem = nil;
+  ///  }
+  ///
+  buf = ";\n\t";
+  buf += "__continue_label_";
+  buf += utostr(ObjCBcLabelNo.back());
+  buf += ": ;";
+  buf += "\n\t\t";
+  buf += "} while (counter < limit);\n\t";
+  buf += "} while ((limit = ";
+  SynthCountByEnumWithState(buf);
+  buf += "));\n\t";
+  buf += elementName;
+  buf += " = ((";
+  buf += elementTypeAsString;
+  buf += ")0);\n\t";
+  buf += "__break_label_";
+  buf += utostr(ObjCBcLabelNo.back());
+  buf += ": ;\n\t";
+  buf += "}\n\t";
+  buf += "else\n\t\t";
+  buf += elementName;
+  buf += " = ((";
+  buf += elementTypeAsString;
+  buf += ")0);\n\t";
+  buf += "}\n";
+
+  // Insert all these *after* the statement body.
+  // FIXME: If this should support Obj-C++, support CXXTryStmt
+  if (isa<CompoundStmt>(S->getBody())) {
+    SourceLocation endBodyLoc = OrigEnd.getLocWithOffset(1);
+    InsertText(endBodyLoc, buf);
+  } else {
+    /* Need to treat single statements specially. For example:
+     *
+     *     for (A *a in b) if (stuff()) break;
+     *     for (A *a in b) xxxyy;
+     *
+     * The following code simply scans ahead to the semi to find the actual end.
+     */
+    const char *stmtBuf = SM->getCharacterData(OrigEnd);
+    const char *semiBuf = strchr(stmtBuf, ';');
+    assert(semiBuf && "Can't find ';'");
+    SourceLocation endBodyLoc = OrigEnd.getLocWithOffset(semiBuf-stmtBuf+1);
+    InsertText(endBodyLoc, buf);
+  }
+  Stmts.pop_back();
+  ObjCBcLabelNo.pop_back();
+  return nullptr;
+}
+
+static void Write_RethrowObject(std::string &buf) {
+  buf += "{ struct _FIN { _FIN(id reth) : rethrow(reth) {}\n";
+  buf += "\t~_FIN() { if (rethrow) objc_exception_throw(rethrow); }\n";
+  buf += "\tid rethrow;\n";
+  buf += "\t} _fin_force_rethow(_rethrow);";
+}
+
+/// RewriteObjCSynchronizedStmt -
+/// This routine rewrites @synchronized(expr) stmt;
+/// into:
+/// objc_sync_enter(expr);
+/// @try stmt @finally { objc_sync_exit(expr); }
+///
+Stmt *RewriteModernObjC::RewriteObjCSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
+  // Get the start location and compute the semi location.
+  SourceLocation startLoc = S->getLocStart();
+  const char *startBuf = SM->getCharacterData(startLoc);
+
+  assert((*startBuf == '@') && "bogus @synchronized location");
+
+  std::string buf;
+  SourceLocation SynchLoc = S->getAtSynchronizedLoc();
+  ConvertSourceLocationToLineDirective(SynchLoc, buf);
+  buf += "{ id _rethrow = 0; id _sync_obj = (id)";
+  
+  const char *lparenBuf = startBuf;
+  while (*lparenBuf != '(') lparenBuf++;
+  ReplaceText(startLoc, lparenBuf-startBuf+1, buf);
+  
+  buf = "; objc_sync_enter(_sync_obj);\n";
+  buf += "try {\n\tstruct _SYNC_EXIT { _SYNC_EXIT(id arg) : sync_exit(arg) {}";
+  buf += "\n\t~_SYNC_EXIT() {objc_sync_exit(sync_exit);}";
+  buf += "\n\tid sync_exit;";
+  buf += "\n\t} _sync_exit(_sync_obj);\n";
+
+  // We can't use S->getSynchExpr()->getLocEnd() to find the end location, since
+  // the sync expression is typically a message expression that's already
+  // been rewritten! (which implies the SourceLocation's are invalid).
+  SourceLocation RParenExprLoc = S->getSynchBody()->getLocStart();
+  const char *RParenExprLocBuf = SM->getCharacterData(RParenExprLoc);
+  while (*RParenExprLocBuf != ')') RParenExprLocBuf--;
+  RParenExprLoc = startLoc.getLocWithOffset(RParenExprLocBuf-startBuf);
+  
+  SourceLocation LBranceLoc = S->getSynchBody()->getLocStart();
+  const char *LBraceLocBuf = SM->getCharacterData(LBranceLoc);
+  assert (*LBraceLocBuf == '{');
+  ReplaceText(RParenExprLoc, (LBraceLocBuf - SM->getCharacterData(RParenExprLoc) + 1), buf);
+  
+  SourceLocation startRBraceLoc = S->getSynchBody()->getLocEnd();
+  assert((*SM->getCharacterData(startRBraceLoc) == '}') &&
+         "bogus @synchronized block");
+  
+  buf = "} catch (id e) {_rethrow = e;}\n";
+  Write_RethrowObject(buf);
+  buf += "}\n";
+  buf += "}\n";
+
+  ReplaceText(startRBraceLoc, 1, buf);
+
+  return nullptr;
+}
+
+void RewriteModernObjC::WarnAboutReturnGotoStmts(Stmt *S)
+{
+  // Perform a bottom up traversal of all children.
+  for (Stmt::child_range CI = S->children(); CI; ++CI)
+    if (*CI)
+      WarnAboutReturnGotoStmts(*CI);
+
+  if (isa<ReturnStmt>(S) || isa<GotoStmt>(S)) {
+    Diags.Report(Context->getFullLoc(S->getLocStart()),
+                 TryFinallyContainsReturnDiag);
+  }
+  return;
+}
+
+Stmt *RewriteModernObjC::RewriteObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt  *S) {
+  SourceLocation startLoc = S->getAtLoc();
+  ReplaceText(startLoc, strlen("@autoreleasepool"), "/* @autoreleasepool */");
+  ReplaceText(S->getSubStmt()->getLocStart(), 1, 
+              "{ __AtAutoreleasePool __autoreleasepool; ");
+
+  return nullptr;
+}
+
+Stmt *RewriteModernObjC::RewriteObjCTryStmt(ObjCAtTryStmt *S) {
+  ObjCAtFinallyStmt *finalStmt = S->getFinallyStmt();
+  bool noCatch = S->getNumCatchStmts() == 0;
+  std::string buf;
+  SourceLocation TryLocation = S->getAtTryLoc();
+  ConvertSourceLocationToLineDirective(TryLocation, buf);
+  
+  if (finalStmt) {
+    if (noCatch)
+      buf += "{ id volatile _rethrow = 0;\n";
+    else {
+      buf += "{ id volatile _rethrow = 0;\ntry {\n";
+    }
+  }
+  // Get the start location and compute the semi location.
+  SourceLocation startLoc = S->getLocStart();
+  const char *startBuf = SM->getCharacterData(startLoc);
+
+  assert((*startBuf == '@') && "bogus @try location");
+  if (finalStmt)
+    ReplaceText(startLoc, 1, buf);
+  else
+    // @try -> try
+    ReplaceText(startLoc, 1, "");
+  
+  for (unsigned I = 0, N = S->getNumCatchStmts(); I != N; ++I) {
+    ObjCAtCatchStmt *Catch = S->getCatchStmt(I);
+    VarDecl *catchDecl = Catch->getCatchParamDecl();
+    
+    startLoc = Catch->getLocStart();
+    bool AtRemoved = false;
+    if (catchDecl) {
+      QualType t = catchDecl->getType();
+      if (const ObjCObjectPointerType *Ptr = t->getAs<ObjCObjectPointerType>()) {
+        // Should be a pointer to a class.
+        ObjCInterfaceDecl *IDecl = Ptr->getObjectType()->getInterface();
+        if (IDecl) {
+          std::string Result;
+          ConvertSourceLocationToLineDirective(Catch->getLocStart(), Result);
+          
+          startBuf = SM->getCharacterData(startLoc);
+          assert((*startBuf == '@') && "bogus @catch location");
+          SourceLocation rParenLoc = Catch->getRParenLoc();
+          const char *rParenBuf = SM->getCharacterData(rParenLoc);
+          
+          // _objc_exc_Foo *_e as argument to catch.
+          Result += "catch (_objc_exc_"; Result += IDecl->getNameAsString();
+          Result += " *_"; Result += catchDecl->getNameAsString();
+          Result += ")";
+          ReplaceText(startLoc, rParenBuf-startBuf+1, Result);
+          // Foo *e = (Foo *)_e;
+          Result.clear();
+          Result = "{ ";
+          Result += IDecl->getNameAsString();
+          Result += " *"; Result += catchDecl->getNameAsString();
+          Result += " = ("; Result += IDecl->getNameAsString(); Result += "*)";
+          Result += "_"; Result += catchDecl->getNameAsString();
+          
+          Result += "; ";
+          SourceLocation lBraceLoc = Catch->getCatchBody()->getLocStart();
+          ReplaceText(lBraceLoc, 1, Result);
+          AtRemoved = true;
+        }
+      }
+    }
+    if (!AtRemoved)
+      // @catch -> catch
+      ReplaceText(startLoc, 1, "");
+      
+  }
+  if (finalStmt) {
+    buf.clear();
+    SourceLocation FinallyLoc = finalStmt->getLocStart();
+    
+    if (noCatch) {
+      ConvertSourceLocationToLineDirective(FinallyLoc, buf);
+      buf += "catch (id e) {_rethrow = e;}\n";
+    }
+    else {
+      buf += "}\n";
+      ConvertSourceLocationToLineDirective(FinallyLoc, buf);
+      buf += "catch (id e) {_rethrow = e;}\n";
+    }
+    
+    SourceLocation startFinalLoc = finalStmt->getLocStart();
+    ReplaceText(startFinalLoc, 8, buf);
+    Stmt *body = finalStmt->getFinallyBody();
+    SourceLocation startFinalBodyLoc = body->getLocStart();
+    buf.clear();
+    Write_RethrowObject(buf);
+    ReplaceText(startFinalBodyLoc, 1, buf);
+    
+    SourceLocation endFinalBodyLoc = body->getLocEnd();
+    ReplaceText(endFinalBodyLoc, 1, "}\n}");
+    // Now check for any return/continue/go statements within the @try.
+    WarnAboutReturnGotoStmts(S->getTryBody());
+  }
+
+  return nullptr;
+}
+
+// This can't be done with ReplaceStmt(S, ThrowExpr), since
+// the throw expression is typically a message expression that's already
+// been rewritten! (which implies the SourceLocation's are invalid).
+Stmt *RewriteModernObjC::RewriteObjCThrowStmt(ObjCAtThrowStmt *S) {
+  // Get the start location and compute the semi location.
+  SourceLocation startLoc = S->getLocStart();
+  const char *startBuf = SM->getCharacterData(startLoc);
+
+  assert((*startBuf == '@') && "bogus @throw location");
+
+  std::string buf;
+  /* void objc_exception_throw(id) __attribute__((noreturn)); */
+  if (S->getThrowExpr())
+    buf = "objc_exception_throw(";
+  else
+    buf = "throw";
+
+  // handle "@  throw" correctly.
+  const char *wBuf = strchr(startBuf, 'w');
+  assert((*wBuf == 'w') && "@throw: can't find 'w'");
+  ReplaceText(startLoc, wBuf-startBuf+1, buf);
+
+  SourceLocation endLoc = S->getLocEnd();
+  const char *endBuf = SM->getCharacterData(endLoc);
+  const char *semiBuf = strchr(endBuf, ';');
+  assert((*semiBuf == ';') && "@throw: can't find ';'");
+  SourceLocation semiLoc = startLoc.getLocWithOffset(semiBuf-startBuf);
+  if (S->getThrowExpr())
+    ReplaceText(semiLoc, 1, ");");
+  return nullptr;
+}
+
+Stmt *RewriteModernObjC::RewriteAtEncode(ObjCEncodeExpr *Exp) {
+  // Create a new string expression.
+  std::string StrEncoding;
+  Context->getObjCEncodingForType(Exp->getEncodedType(), StrEncoding);
+  Expr *Replacement = getStringLiteral(StrEncoding);
+  ReplaceStmt(Exp, Replacement);
+
+  // Replace this subexpr in the parent.
+  // delete Exp; leak for now, see RewritePropertyOrImplicitSetter() usage for more info.
+  return Replacement;
+}
+
+Stmt *RewriteModernObjC::RewriteAtSelector(ObjCSelectorExpr *Exp) {
+  if (!SelGetUidFunctionDecl)
+    SynthSelGetUidFunctionDecl();
+  assert(SelGetUidFunctionDecl && "Can't find sel_registerName() decl");
+  // Create a call to sel_registerName("selName").
+  SmallVector<Expr*, 8> SelExprs;
+  SelExprs.push_back(getStringLiteral(Exp->getSelector().getAsString()));
+  CallExpr *SelExp = SynthesizeCallToFunctionDecl(SelGetUidFunctionDecl,
+                                                 &SelExprs[0], SelExprs.size());
+  ReplaceStmt(Exp, SelExp);
+  // delete Exp; leak for now, see RewritePropertyOrImplicitSetter() usage for more info.
+  return SelExp;
+}
+
+CallExpr *RewriteModernObjC::SynthesizeCallToFunctionDecl(
+  FunctionDecl *FD, Expr **args, unsigned nargs, SourceLocation StartLoc,
+                                                    SourceLocation EndLoc) {
+  // Get the type, we will need to reference it in a couple spots.
+  QualType msgSendType = FD->getType();
+
+  // Create a reference to the objc_msgSend() declaration.
+  DeclRefExpr *DRE =
+    new (Context) DeclRefExpr(FD, false, msgSendType, VK_LValue, SourceLocation());
+
+  // Now, we cast the reference to a pointer to the objc_msgSend type.
+  QualType pToFunc = Context->getPointerType(msgSendType);
+  ImplicitCastExpr *ICE = 
+    ImplicitCastExpr::Create(*Context, pToFunc, CK_FunctionToPointerDecay,
+                             DRE, nullptr, VK_RValue);
+
+  const FunctionType *FT = msgSendType->getAs<FunctionType>();
+
+  CallExpr *Exp =  
+    new (Context) CallExpr(*Context, ICE, llvm::makeArrayRef(args, nargs),
+                           FT->getCallResultType(*Context),
+                           VK_RValue, EndLoc);
+  return Exp;
+}
+
+static bool scanForProtocolRefs(const char *startBuf, const char *endBuf,
+                                const char *&startRef, const char *&endRef) {
+  while (startBuf < endBuf) {
+    if (*startBuf == '<')
+      startRef = startBuf; // mark the start.
+    if (*startBuf == '>') {
+      if (startRef && *startRef == '<') {
+        endRef = startBuf; // mark the end.
+        return true;
+      }
+      return false;
+    }
+    startBuf++;
+  }
+  return false;
+}
+
+static void scanToNextArgument(const char *&argRef) {
+  int angle = 0;
+  while (*argRef != ')' && (*argRef != ',' || angle > 0)) {
+    if (*argRef == '<')
+      angle++;
+    else if (*argRef == '>')
+      angle--;
+    argRef++;
+  }
+  assert(angle == 0 && "scanToNextArgument - bad protocol type syntax");
+}
+
+bool RewriteModernObjC::needToScanForQualifiers(QualType T) {
+  if (T->isObjCQualifiedIdType())
+    return true;
+  if (const PointerType *PT = T->getAs<PointerType>()) {
+    if (PT->getPointeeType()->isObjCQualifiedIdType())
+      return true;
+  }
+  if (T->isObjCObjectPointerType()) {
+    T = T->getPointeeType();
+    return T->isObjCQualifiedInterfaceType();
+  }
+  if (T->isArrayType()) {
+    QualType ElemTy = Context->getBaseElementType(T);
+    return needToScanForQualifiers(ElemTy);
+  }
+  return false;
+}
+
+void RewriteModernObjC::RewriteObjCQualifiedInterfaceTypes(Expr *E) {
+  QualType Type = E->getType();
+  if (needToScanForQualifiers(Type)) {
+    SourceLocation Loc, EndLoc;
+
+    if (const CStyleCastExpr *ECE = dyn_cast<CStyleCastExpr>(E)) {
+      Loc = ECE->getLParenLoc();
+      EndLoc = ECE->getRParenLoc();
+    } else {
+      Loc = E->getLocStart();
+      EndLoc = E->getLocEnd();
+    }
+    // This will defend against trying to rewrite synthesized expressions.
+    if (Loc.isInvalid() || EndLoc.isInvalid())
+      return;
+
+    const char *startBuf = SM->getCharacterData(Loc);
+    const char *endBuf = SM->getCharacterData(EndLoc);
+    const char *startRef = nullptr, *endRef = nullptr;
+    if (scanForProtocolRefs(startBuf, endBuf, startRef, endRef)) {
+      // Get the locations of the startRef, endRef.
+      SourceLocation LessLoc = Loc.getLocWithOffset(startRef-startBuf);
+      SourceLocation GreaterLoc = Loc.getLocWithOffset(endRef-startBuf+1);
+      // Comment out the protocol references.
+      InsertText(LessLoc, "/*");
+      InsertText(GreaterLoc, "*/");
+    }
+  }
+}
+
+void RewriteModernObjC::RewriteObjCQualifiedInterfaceTypes(Decl *Dcl) {
+  SourceLocation Loc;
+  QualType Type;
+  const FunctionProtoType *proto = nullptr;
+  if (VarDecl *VD = dyn_cast<VarDecl>(Dcl)) {
+    Loc = VD->getLocation();
+    Type = VD->getType();
+  }
+  else if (FunctionDecl *FD = dyn_cast<FunctionDecl>(Dcl)) {
+    Loc = FD->getLocation();
+    // Check for ObjC 'id' and class types that have been adorned with protocol
+    // information (id<p>, C<p>*). The protocol references need to be rewritten!
+    const FunctionType *funcType = FD->getType()->getAs<FunctionType>();
+    assert(funcType && "missing function type");
+    proto = dyn_cast<FunctionProtoType>(funcType);
+    if (!proto)
+      return;
+    Type = proto->getReturnType();
+  }
+  else if (FieldDecl *FD = dyn_cast<FieldDecl>(Dcl)) {
+    Loc = FD->getLocation();
+    Type = FD->getType();
+  }
+  else if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(Dcl)) {
+    Loc = TD->getLocation();
+    Type = TD->getUnderlyingType();
+  }
+  else
+    return;
+
+  if (needToScanForQualifiers(Type)) {
+    // Since types are unique, we need to scan the buffer.
+
+    const char *endBuf = SM->getCharacterData(Loc);
+    const char *startBuf = endBuf;
+    while (*startBuf != ';' && *startBuf != '<' && startBuf != MainFileStart)
+      startBuf--; // scan backward (from the decl location) for return type.
+    const char *startRef = nullptr, *endRef = nullptr;
+    if (scanForProtocolRefs(startBuf, endBuf, startRef, endRef)) {
+      // Get the locations of the startRef, endRef.
+      SourceLocation LessLoc = Loc.getLocWithOffset(startRef-endBuf);
+      SourceLocation GreaterLoc = Loc.getLocWithOffset(endRef-endBuf+1);
+      // Comment out the protocol references.
+      InsertText(LessLoc, "/*");
+      InsertText(GreaterLoc, "*/");
+    }
+  }
+  if (!proto)
+      return; // most likely, was a variable
+  // Now check arguments.
+  const char *startBuf = SM->getCharacterData(Loc);
+  const char *startFuncBuf = startBuf;
+  for (unsigned i = 0; i < proto->getNumParams(); i++) {
+    if (needToScanForQualifiers(proto->getParamType(i))) {
+      // Since types are unique, we need to scan the buffer.
+
+      const char *endBuf = startBuf;
+      // scan forward (from the decl location) for argument types.
+      scanToNextArgument(endBuf);
+      const char *startRef = nullptr, *endRef = nullptr;
+      if (scanForProtocolRefs(startBuf, endBuf, startRef, endRef)) {
+        // Get the locations of the startRef, endRef.
+        SourceLocation LessLoc =
+          Loc.getLocWithOffset(startRef-startFuncBuf);
+        SourceLocation GreaterLoc =
+          Loc.getLocWithOffset(endRef-startFuncBuf+1);
+        // Comment out the protocol references.
+        InsertText(LessLoc, "/*");
+        InsertText(GreaterLoc, "*/");
+      }
+      startBuf = ++endBuf;
+    }
+    else {
+      // If the function name is derived from a macro expansion, then the
+      // argument buffer will not follow the name. Need to speak with Chris.
+      while (*startBuf && *startBuf != ')' && *startBuf != ',')
+        startBuf++; // scan forward (from the decl location) for argument types.
+      startBuf++;
+    }
+  }
+}
+
+void RewriteModernObjC::RewriteTypeOfDecl(VarDecl *ND) {
+  QualType QT = ND->getType();
+  const Type* TypePtr = QT->getAs<Type>();
+  if (!isa<TypeOfExprType>(TypePtr))
+    return;
+  while (isa<TypeOfExprType>(TypePtr)) {
+    const TypeOfExprType *TypeOfExprTypePtr = cast<TypeOfExprType>(TypePtr);
+    QT = TypeOfExprTypePtr->getUnderlyingExpr()->getType();
+    TypePtr = QT->getAs<Type>();
+  }
+  // FIXME. This will not work for multiple declarators; as in:
+  // __typeof__(a) b,c,d;
+  std::string TypeAsString(QT.getAsString(Context->getPrintingPolicy()));
+  SourceLocation DeclLoc = ND->getTypeSpecStartLoc();
+  const char *startBuf = SM->getCharacterData(DeclLoc);
+  if (ND->getInit()) {
+    std::string Name(ND->getNameAsString());
+    TypeAsString += " " + Name + " = ";
+    Expr *E = ND->getInit();
+    SourceLocation startLoc;
+    if (const CStyleCastExpr *ECE = dyn_cast<CStyleCastExpr>(E))
+      startLoc = ECE->getLParenLoc();
+    else
+      startLoc = E->getLocStart();
+    startLoc = SM->getExpansionLoc(startLoc);
+    const char *endBuf = SM->getCharacterData(startLoc);
+    ReplaceText(DeclLoc, endBuf-startBuf-1, TypeAsString);
+  }
+  else {
+    SourceLocation X = ND->getLocEnd();
+    X = SM->getExpansionLoc(X);
+    const char *endBuf = SM->getCharacterData(X);
+    ReplaceText(DeclLoc, endBuf-startBuf-1, TypeAsString);
+  }
+}
+
+// SynthSelGetUidFunctionDecl - SEL sel_registerName(const char *str);
+void RewriteModernObjC::SynthSelGetUidFunctionDecl() {
+  IdentifierInfo *SelGetUidIdent = &Context->Idents.get("sel_registerName");
+  SmallVector<QualType, 16> ArgTys;
+  ArgTys.push_back(Context->getPointerType(Context->CharTy.withConst()));
+  QualType getFuncType =
+    getSimpleFunctionType(Context->getObjCSelType(), ArgTys);
+  SelGetUidFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                               SourceLocation(),
+                                               SourceLocation(),
+                                               SelGetUidIdent, getFuncType,
+                                               nullptr, SC_Extern);
+}
+
+void RewriteModernObjC::RewriteFunctionDecl(FunctionDecl *FD) {
+  // declared in <objc/objc.h>
+  if (FD->getIdentifier() &&
+      FD->getName() == "sel_registerName") {
+    SelGetUidFunctionDecl = FD;
+    return;
+  }
+  RewriteObjCQualifiedInterfaceTypes(FD);
+}
+
+void RewriteModernObjC::RewriteBlockPointerType(std::string& Str, QualType Type) {
+  std::string TypeString(Type.getAsString(Context->getPrintingPolicy()));
+  const char *argPtr = TypeString.c_str();
+  if (!strchr(argPtr, '^')) {
+    Str += TypeString;
+    return;
+  }
+  while (*argPtr) {
+    Str += (*argPtr == '^' ? '*' : *argPtr);
+    argPtr++;
+  }
+}
+
+// FIXME. Consolidate this routine with RewriteBlockPointerType.
+void RewriteModernObjC::RewriteBlockPointerTypeVariable(std::string& Str,
+                                                  ValueDecl *VD) {
+  QualType Type = VD->getType();
+  std::string TypeString(Type.getAsString(Context->getPrintingPolicy()));
+  const char *argPtr = TypeString.c_str();
+  int paren = 0;
+  while (*argPtr) {
+    switch (*argPtr) {
+      case '(':
+        Str += *argPtr;
+        paren++;
+        break;
+      case ')':
+        Str += *argPtr;
+        paren--;
+        break;
+      case '^':
+        Str += '*';
+        if (paren == 1)
+          Str += VD->getNameAsString();
+        break;
+      default:
+        Str += *argPtr;
+        break;
+    }
+    argPtr++;
+  }
+}
+
+void RewriteModernObjC::RewriteBlockLiteralFunctionDecl(FunctionDecl *FD) {
+  SourceLocation FunLocStart = FD->getTypeSpecStartLoc();
+  const FunctionType *funcType = FD->getType()->getAs<FunctionType>();
+  const FunctionProtoType *proto = dyn_cast<FunctionProtoType>(funcType);
+  if (!proto)
+    return;
+  QualType Type = proto->getReturnType();
+  std::string FdStr = Type.getAsString(Context->getPrintingPolicy());
+  FdStr += " ";
+  FdStr += FD->getName();
+  FdStr +=  "(";
+  unsigned numArgs = proto->getNumParams();
+  for (unsigned i = 0; i < numArgs; i++) {
+    QualType ArgType = proto->getParamType(i);
+  RewriteBlockPointerType(FdStr, ArgType);
+  if (i+1 < numArgs)
+    FdStr += ", ";
+  }
+  if (FD->isVariadic()) {
+    FdStr +=  (numArgs > 0) ? ", ...);\n" : "...);\n";
+  }
+  else
+    FdStr +=  ");\n";
+  InsertText(FunLocStart, FdStr);
+}
+
+// SynthSuperConstructorFunctionDecl - id __rw_objc_super(id obj, id super);
+void RewriteModernObjC::SynthSuperConstructorFunctionDecl() {
+  if (SuperConstructorFunctionDecl)
+    return;
+  IdentifierInfo *msgSendIdent = &Context->Idents.get("__rw_objc_super");
+  SmallVector<QualType, 16> ArgTys;
+  QualType argT = Context->getObjCIdType();
+  assert(!argT.isNull() && "Can't find 'id' type");
+  ArgTys.push_back(argT);
+  ArgTys.push_back(argT);
+  QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
+                                               ArgTys);
+  SuperConstructorFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                                     SourceLocation(),
+                                                     SourceLocation(),
+                                                     msgSendIdent, msgSendType,
+                                                     nullptr, SC_Extern);
+}
+
+// SynthMsgSendFunctionDecl - id objc_msgSend(id self, SEL op, ...);
+void RewriteModernObjC::SynthMsgSendFunctionDecl() {
+  IdentifierInfo *msgSendIdent = &Context->Idents.get("objc_msgSend");
+  SmallVector<QualType, 16> ArgTys;
+  QualType argT = Context->getObjCIdType();
+  assert(!argT.isNull() && "Can't find 'id' type");
+  ArgTys.push_back(argT);
+  argT = Context->getObjCSelType();
+  assert(!argT.isNull() && "Can't find 'SEL' type");
+  ArgTys.push_back(argT);
+  QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
+                                               ArgTys, /*isVariadic=*/true);
+  MsgSendFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                             SourceLocation(),
+                                             SourceLocation(),
+                                             msgSendIdent, msgSendType, nullptr,
+                                             SC_Extern);
+}
+
+// SynthMsgSendSuperFunctionDecl - id objc_msgSendSuper(void);
+void RewriteModernObjC::SynthMsgSendSuperFunctionDecl() {
+  IdentifierInfo *msgSendIdent = &Context->Idents.get("objc_msgSendSuper");
+  SmallVector<QualType, 2> ArgTys;
+  ArgTys.push_back(Context->VoidTy);
+  QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
+                                               ArgTys, /*isVariadic=*/true);
+  MsgSendSuperFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                                  SourceLocation(),
+                                                  SourceLocation(),
+                                                  msgSendIdent, msgSendType,
+                                                  nullptr, SC_Extern);
+}
+
+// SynthMsgSendStretFunctionDecl - id objc_msgSend_stret(id self, SEL op, ...);
+void RewriteModernObjC::SynthMsgSendStretFunctionDecl() {
+  IdentifierInfo *msgSendIdent = &Context->Idents.get("objc_msgSend_stret");
+  SmallVector<QualType, 16> ArgTys;
+  QualType argT = Context->getObjCIdType();
+  assert(!argT.isNull() && "Can't find 'id' type");
+  ArgTys.push_back(argT);
+  argT = Context->getObjCSelType();
+  assert(!argT.isNull() && "Can't find 'SEL' type");
+  ArgTys.push_back(argT);
+  QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
+                                               ArgTys, /*isVariadic=*/true);
+  MsgSendStretFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                                  SourceLocation(),
+                                                  SourceLocation(),
+                                                  msgSendIdent, msgSendType,
+                                                  nullptr, SC_Extern);
+}
+
+// SynthMsgSendSuperStretFunctionDecl -
+// id objc_msgSendSuper_stret(void);
+void RewriteModernObjC::SynthMsgSendSuperStretFunctionDecl() {
+  IdentifierInfo *msgSendIdent =
+    &Context->Idents.get("objc_msgSendSuper_stret");
+  SmallVector<QualType, 2> ArgTys;
+  ArgTys.push_back(Context->VoidTy);
+  QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
+                                               ArgTys, /*isVariadic=*/true);
+  MsgSendSuperStretFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                                       SourceLocation(),
+                                                       SourceLocation(),
+                                                       msgSendIdent,
+                                                       msgSendType, nullptr,
+                                                       SC_Extern);
+}
+
+// SynthMsgSendFpretFunctionDecl - double objc_msgSend_fpret(id self, SEL op, ...);
+void RewriteModernObjC::SynthMsgSendFpretFunctionDecl() {
+  IdentifierInfo *msgSendIdent = &Context->Idents.get("objc_msgSend_fpret");
+  SmallVector<QualType, 16> ArgTys;
+  QualType argT = Context->getObjCIdType();
+  assert(!argT.isNull() && "Can't find 'id' type");
+  ArgTys.push_back(argT);
+  argT = Context->getObjCSelType();
+  assert(!argT.isNull() && "Can't find 'SEL' type");
+  ArgTys.push_back(argT);
+  QualType msgSendType = getSimpleFunctionType(Context->DoubleTy,
+                                               ArgTys, /*isVariadic=*/true);
+  MsgSendFpretFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                                  SourceLocation(),
+                                                  SourceLocation(),
+                                                  msgSendIdent, msgSendType,
+                                                  nullptr, SC_Extern);
+}
+
+// SynthGetClassFunctionDecl - Class objc_getClass(const char *name);
+void RewriteModernObjC::SynthGetClassFunctionDecl() {
+  IdentifierInfo *getClassIdent = &Context->Idents.get("objc_getClass");
+  SmallVector<QualType, 16> ArgTys;
+  ArgTys.push_back(Context->getPointerType(Context->CharTy.withConst()));
+  QualType getClassType = getSimpleFunctionType(Context->getObjCClassType(),
+                                                ArgTys);
+  GetClassFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                              SourceLocation(),
+                                              SourceLocation(),
+                                              getClassIdent, getClassType,
+                                              nullptr, SC_Extern);
+}
+
+// SynthGetSuperClassFunctionDecl - Class class_getSuperclass(Class cls);
+void RewriteModernObjC::SynthGetSuperClassFunctionDecl() {
+  IdentifierInfo *getSuperClassIdent = 
+    &Context->Idents.get("class_getSuperclass");
+  SmallVector<QualType, 16> ArgTys;
+  ArgTys.push_back(Context->getObjCClassType());
+  QualType getClassType = getSimpleFunctionType(Context->getObjCClassType(),
+                                                ArgTys);
+  GetSuperClassFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                                   SourceLocation(),
+                                                   SourceLocation(),
+                                                   getSuperClassIdent,
+                                                   getClassType, nullptr,
+                                                   SC_Extern);
+}
+
+// SynthGetMetaClassFunctionDecl - Class objc_getMetaClass(const char *name);
+void RewriteModernObjC::SynthGetMetaClassFunctionDecl() {
+  IdentifierInfo *getClassIdent = &Context->Idents.get("objc_getMetaClass");
+  SmallVector<QualType, 16> ArgTys;
+  ArgTys.push_back(Context->getPointerType(Context->CharTy.withConst()));
+  QualType getClassType = getSimpleFunctionType(Context->getObjCClassType(),
+                                                ArgTys);
+  GetMetaClassFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                                  SourceLocation(),
+                                                  SourceLocation(),
+                                                  getClassIdent, getClassType,
+                                                  nullptr, SC_Extern);
+}
+
+Stmt *RewriteModernObjC::RewriteObjCStringLiteral(ObjCStringLiteral *Exp) {
+  assert (Exp != nullptr && "Expected non-null ObjCStringLiteral");
+  QualType strType = getConstantStringStructType();
+
+  std::string S = "__NSConstantStringImpl_";
+
+  std::string tmpName = InFileName;
+  unsigned i;
+  for (i=0; i < tmpName.length(); i++) {
+    char c = tmpName.at(i);
+    // replace any non-alphanumeric characters with '_'.
+    if (!isAlphanumeric(c))
+      tmpName[i] = '_';
+  }
+  S += tmpName;
+  S += "_";
+  S += utostr(NumObjCStringLiterals++);
+
+  Preamble += "static __NSConstantStringImpl " + S;
+  Preamble += " __attribute__ ((section (\"__DATA, __cfstring\"))) = {__CFConstantStringClassReference,";
+  Preamble += "0x000007c8,"; // utf8_str
+  // The pretty printer for StringLiteral handles escape characters properly.
+  std::string prettyBufS;
+  llvm::raw_string_ostream prettyBuf(prettyBufS);
+  Exp->getString()->printPretty(prettyBuf, nullptr, PrintingPolicy(LangOpts));
+  Preamble += prettyBuf.str();
+  Preamble += ",";
+  Preamble += utostr(Exp->getString()->getByteLength()) + "};\n";
+
+  VarDecl *NewVD = VarDecl::Create(*Context, TUDecl, SourceLocation(),
+                                   SourceLocation(), &Context->Idents.get(S),
+                                   strType, nullptr, SC_Static);
+  DeclRefExpr *DRE = new (Context) DeclRefExpr(NewVD, false, strType, VK_LValue,
+                                               SourceLocation());
+  Expr *Unop = new (Context) UnaryOperator(DRE, UO_AddrOf,
+                                 Context->getPointerType(DRE->getType()),
+                                           VK_RValue, OK_Ordinary,
+                                           SourceLocation());
+  // cast to NSConstantString *
+  CastExpr *cast = NoTypeInfoCStyleCastExpr(Context, Exp->getType(),
+                                            CK_CPointerToObjCPointerCast, Unop);
+  ReplaceStmt(Exp, cast);
+  // delete Exp; leak for now, see RewritePropertyOrImplicitSetter() usage for more info.
+  return cast;
+}
+
+Stmt *RewriteModernObjC::RewriteObjCBoolLiteralExpr(ObjCBoolLiteralExpr *Exp) {
+  unsigned IntSize =
+    static_cast<unsigned>(Context->getTypeSize(Context->IntTy));
+  
+  Expr *FlagExp = IntegerLiteral::Create(*Context, 
+                                         llvm::APInt(IntSize, Exp->getValue()), 
+                                         Context->IntTy, Exp->getLocation());
+  CastExpr *cast = NoTypeInfoCStyleCastExpr(Context, Context->ObjCBuiltinBoolTy,
+                                            CK_BitCast, FlagExp);
+  ParenExpr *PE = new (Context) ParenExpr(Exp->getLocation(), Exp->getExprLoc(), 
+                                          cast);
+  ReplaceStmt(Exp, PE);
+  return PE;
+}
+
+Stmt *RewriteModernObjC::RewriteObjCBoxedExpr(ObjCBoxedExpr *Exp) {
+  // synthesize declaration of helper functions needed in this routine.
+  if (!SelGetUidFunctionDecl)
+    SynthSelGetUidFunctionDecl();
+  // use objc_msgSend() for all.
+  if (!MsgSendFunctionDecl)
+    SynthMsgSendFunctionDecl();
+  if (!GetClassFunctionDecl)
+    SynthGetClassFunctionDecl();
+  
+  FunctionDecl *MsgSendFlavor = MsgSendFunctionDecl;
+  SourceLocation StartLoc = Exp->getLocStart();
+  SourceLocation EndLoc = Exp->getLocEnd();
+  
+  // Synthesize a call to objc_msgSend().
+  SmallVector<Expr*, 4> MsgExprs;
+  SmallVector<Expr*, 4> ClsExprs;
+  
+  // Create a call to objc_getClass("<BoxingClass>"). It will be the 1st argument.
+  ObjCMethodDecl *BoxingMethod = Exp->getBoxingMethod();
+  ObjCInterfaceDecl *BoxingClass = BoxingMethod->getClassInterface();
+  
+  IdentifierInfo *clsName = BoxingClass->getIdentifier();
+  ClsExprs.push_back(getStringLiteral(clsName->getName()));
+  CallExpr *Cls = SynthesizeCallToFunctionDecl(GetClassFunctionDecl,
+                                               &ClsExprs[0],
+                                               ClsExprs.size(), 
+                                               StartLoc, EndLoc);
+  MsgExprs.push_back(Cls);
+  
+  // Create a call to sel_registerName("<BoxingMethod>:"), etc.
+  // it will be the 2nd argument.
+  SmallVector<Expr*, 4> SelExprs;
+  SelExprs.push_back(
+      getStringLiteral(BoxingMethod->getSelector().getAsString()));
+  CallExpr *SelExp = SynthesizeCallToFunctionDecl(SelGetUidFunctionDecl,
+                                                  &SelExprs[0], SelExprs.size(),
+                                                  StartLoc, EndLoc);
+  MsgExprs.push_back(SelExp);
+  
+  // User provided sub-expression is the 3rd, and last, argument.
+  Expr *subExpr  = Exp->getSubExpr();
+  if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(subExpr)) {
+    QualType type = ICE->getType();
+    const Expr *SubExpr = ICE->IgnoreParenImpCasts();
+    CastKind CK = CK_BitCast;
+    if (SubExpr->getType()->isIntegralType(*Context) && type->isBooleanType())
+      CK = CK_IntegralToBoolean;
+    subExpr = NoTypeInfoCStyleCastExpr(Context, type, CK, subExpr);
+  }
+  MsgExprs.push_back(subExpr);
+  
+  SmallVector<QualType, 4> ArgTypes;
+  ArgTypes.push_back(Context->getObjCIdType());
+  ArgTypes.push_back(Context->getObjCSelType());
+  for (const auto PI : BoxingMethod->parameters())
+    ArgTypes.push_back(PI->getType());
+  
+  QualType returnType = Exp->getType();
+  // Get the type, we will need to reference it in a couple spots.
+  QualType msgSendType = MsgSendFlavor->getType();
+  
+  // Create a reference to the objc_msgSend() declaration.
+  DeclRefExpr *DRE = new (Context) DeclRefExpr(MsgSendFlavor, false, msgSendType,
+                                               VK_LValue, SourceLocation());
+  
+  CastExpr *cast = NoTypeInfoCStyleCastExpr(Context,
+                                            Context->getPointerType(Context->VoidTy),
+                                            CK_BitCast, DRE);
+  
+  // Now do the "normal" pointer to function cast.
+  QualType castType =
+    getSimpleFunctionType(returnType, ArgTypes, BoxingMethod->isVariadic());
+  castType = Context->getPointerType(castType);
+  cast = NoTypeInfoCStyleCastExpr(Context, castType, CK_BitCast,
+                                  cast);
+  
+  // Don't forget the parens to enforce the proper binding.
+  ParenExpr *PE = new (Context) ParenExpr(StartLoc, EndLoc, cast);
+  
+  const FunctionType *FT = msgSendType->getAs<FunctionType>();
+  CallExpr *CE = new (Context)
+      CallExpr(*Context, PE, MsgExprs, FT->getReturnType(), VK_RValue, EndLoc);
+  ReplaceStmt(Exp, CE);
+  return CE;
+}
+
+Stmt *RewriteModernObjC::RewriteObjCArrayLiteralExpr(ObjCArrayLiteral *Exp) {
+  // synthesize declaration of helper functions needed in this routine.
+  if (!SelGetUidFunctionDecl)
+    SynthSelGetUidFunctionDecl();
+  // use objc_msgSend() for all.
+  if (!MsgSendFunctionDecl)
+    SynthMsgSendFunctionDecl();
+  if (!GetClassFunctionDecl)
+    SynthGetClassFunctionDecl();
+  
+  FunctionDecl *MsgSendFlavor = MsgSendFunctionDecl;
+  SourceLocation StartLoc = Exp->getLocStart();
+  SourceLocation EndLoc = Exp->getLocEnd();
+  
+  // Build the expression: __NSContainer_literal(int, ...).arr
+  QualType IntQT = Context->IntTy;
+  QualType NSArrayFType =
+    getSimpleFunctionType(Context->VoidTy, IntQT, true);
+  std::string NSArrayFName("__NSContainer_literal");
+  FunctionDecl *NSArrayFD = SynthBlockInitFunctionDecl(NSArrayFName);
+  DeclRefExpr *NSArrayDRE = 
+    new (Context) DeclRefExpr(NSArrayFD, false, NSArrayFType, VK_RValue,
+                              SourceLocation());
+
+  SmallVector<Expr*, 16> InitExprs;
+  unsigned NumElements = Exp->getNumElements();
+  unsigned UnsignedIntSize = 
+    static_cast<unsigned>(Context->getTypeSize(Context->UnsignedIntTy));
+  Expr *count = IntegerLiteral::Create(*Context,
+                                       llvm::APInt(UnsignedIntSize, NumElements),
+                                       Context->UnsignedIntTy, SourceLocation());
+  InitExprs.push_back(count);
+  for (unsigned i = 0; i < NumElements; i++)
+    InitExprs.push_back(Exp->getElement(i));
+  Expr *NSArrayCallExpr = 
+    new (Context) CallExpr(*Context, NSArrayDRE, InitExprs,
+                           NSArrayFType, VK_LValue, SourceLocation());
+
+  FieldDecl *ARRFD = FieldDecl::Create(*Context, nullptr, SourceLocation(),
+                                    SourceLocation(),
+                                    &Context->Idents.get("arr"),
+                                    Context->getPointerType(Context->VoidPtrTy),
+                                    nullptr, /*BitWidth=*/nullptr,
+                                    /*Mutable=*/true, ICIS_NoInit);
+  MemberExpr *ArrayLiteralME = 
+    new (Context) MemberExpr(NSArrayCallExpr, false, ARRFD, 
+                             SourceLocation(),
+                             ARRFD->getType(), VK_LValue,
+                             OK_Ordinary);
+  QualType ConstIdT = Context->getObjCIdType().withConst();
+  CStyleCastExpr * ArrayLiteralObjects = 
+    NoTypeInfoCStyleCastExpr(Context, 
+                             Context->getPointerType(ConstIdT),
+                             CK_BitCast,
+                             ArrayLiteralME);
+  
+  // Synthesize a call to objc_msgSend().
+  SmallVector<Expr*, 32> MsgExprs;
+  SmallVector<Expr*, 4> ClsExprs;
+  QualType expType = Exp->getType();
+  
+  // Create a call to objc_getClass("NSArray"). It will be th 1st argument.
+  ObjCInterfaceDecl *Class = 
+    expType->getPointeeType()->getAs<ObjCObjectType>()->getInterface();
+  
+  IdentifierInfo *clsName = Class->getIdentifier();
+  ClsExprs.push_back(getStringLiteral(clsName->getName()));
+  CallExpr *Cls = SynthesizeCallToFunctionDecl(GetClassFunctionDecl,
+                                               &ClsExprs[0],
+                                               ClsExprs.size(), 
+                                               StartLoc, EndLoc);
+  MsgExprs.push_back(Cls);
+  
+  // Create a call to sel_registerName("arrayWithObjects:count:").
+  // it will be the 2nd argument.
+  SmallVector<Expr*, 4> SelExprs;
+  ObjCMethodDecl *ArrayMethod = Exp->getArrayWithObjectsMethod();
+  SelExprs.push_back(
+      getStringLiteral(ArrayMethod->getSelector().getAsString()));
+  CallExpr *SelExp = SynthesizeCallToFunctionDecl(SelGetUidFunctionDecl,
+                                                  &SelExprs[0], SelExprs.size(),
+                                                  StartLoc, EndLoc);
+  MsgExprs.push_back(SelExp);
+  
+  // (const id [])objects
+  MsgExprs.push_back(ArrayLiteralObjects);
+  
+  // (NSUInteger)cnt
+  Expr *cnt = IntegerLiteral::Create(*Context,
+                                     llvm::APInt(UnsignedIntSize, NumElements),
+                                     Context->UnsignedIntTy, SourceLocation());
+  MsgExprs.push_back(cnt);
+  
+  
+  SmallVector<QualType, 4> ArgTypes;
+  ArgTypes.push_back(Context->getObjCIdType());
+  ArgTypes.push_back(Context->getObjCSelType());
+  for (const auto *PI : ArrayMethod->params())
+    ArgTypes.push_back(PI->getType());
+  
+  QualType returnType = Exp->getType();
+  // Get the type, we will need to reference it in a couple spots.
+  QualType msgSendType = MsgSendFlavor->getType();
+  
+  // Create a reference to the objc_msgSend() declaration.
+  DeclRefExpr *DRE = new (Context) DeclRefExpr(MsgSendFlavor, false, msgSendType,
+                                               VK_LValue, SourceLocation());
+  
+  CastExpr *cast = NoTypeInfoCStyleCastExpr(Context,
+                                            Context->getPointerType(Context->VoidTy),
+                                            CK_BitCast, DRE);
+  
+  // Now do the "normal" pointer to function cast.
+  QualType castType =
+  getSimpleFunctionType(returnType, ArgTypes, ArrayMethod->isVariadic());
+  castType = Context->getPointerType(castType);
+  cast = NoTypeInfoCStyleCastExpr(Context, castType, CK_BitCast,
+                                  cast);
+  
+  // Don't forget the parens to enforce the proper binding.
+  ParenExpr *PE = new (Context) ParenExpr(StartLoc, EndLoc, cast);
+  
+  const FunctionType *FT = msgSendType->getAs<FunctionType>();
+  CallExpr *CE = new (Context)
+      CallExpr(*Context, PE, MsgExprs, FT->getReturnType(), VK_RValue, EndLoc);
+  ReplaceStmt(Exp, CE);
+  return CE;
+}
+
+Stmt *RewriteModernObjC::RewriteObjCDictionaryLiteralExpr(ObjCDictionaryLiteral *Exp) {
+  // synthesize declaration of helper functions needed in this routine.
+  if (!SelGetUidFunctionDecl)
+    SynthSelGetUidFunctionDecl();
+  // use objc_msgSend() for all.
+  if (!MsgSendFunctionDecl)
+    SynthMsgSendFunctionDecl();
+  if (!GetClassFunctionDecl)
+    SynthGetClassFunctionDecl();
+  
+  FunctionDecl *MsgSendFlavor = MsgSendFunctionDecl;
+  SourceLocation StartLoc = Exp->getLocStart();
+  SourceLocation EndLoc = Exp->getLocEnd();
+  
+  // Build the expression: __NSContainer_literal(int, ...).arr
+  QualType IntQT = Context->IntTy;
+  QualType NSDictFType =
+    getSimpleFunctionType(Context->VoidTy, IntQT, true);
+  std::string NSDictFName("__NSContainer_literal");
+  FunctionDecl *NSDictFD = SynthBlockInitFunctionDecl(NSDictFName);
+  DeclRefExpr *NSDictDRE = 
+    new (Context) DeclRefExpr(NSDictFD, false, NSDictFType, VK_RValue,
+                              SourceLocation());
+  
+  SmallVector<Expr*, 16> KeyExprs;
+  SmallVector<Expr*, 16> ValueExprs;
+  
+  unsigned NumElements = Exp->getNumElements();
+  unsigned UnsignedIntSize = 
+    static_cast<unsigned>(Context->getTypeSize(Context->UnsignedIntTy));
+  Expr *count = IntegerLiteral::Create(*Context,
+                                       llvm::APInt(UnsignedIntSize, NumElements),
+                                       Context->UnsignedIntTy, SourceLocation());
+  KeyExprs.push_back(count);
+  ValueExprs.push_back(count);
+  for (unsigned i = 0; i < NumElements; i++) {
+    ObjCDictionaryElement Element = Exp->getKeyValueElement(i);
+    KeyExprs.push_back(Element.Key);
+    ValueExprs.push_back(Element.Value);
+  }
+  
+  // (const id [])objects
+  Expr *NSValueCallExpr = 
+    new (Context) CallExpr(*Context, NSDictDRE, ValueExprs,
+                           NSDictFType, VK_LValue, SourceLocation());
+
+  FieldDecl *ARRFD = FieldDecl::Create(*Context, nullptr, SourceLocation(),
+                                       SourceLocation(),
+                                       &Context->Idents.get("arr"),
+                                       Context->getPointerType(Context->VoidPtrTy),
+                                       nullptr, /*BitWidth=*/nullptr,
+                                       /*Mutable=*/true, ICIS_NoInit);
+  MemberExpr *DictLiteralValueME = 
+    new (Context) MemberExpr(NSValueCallExpr, false, ARRFD, 
+                             SourceLocation(),
+                             ARRFD->getType(), VK_LValue,
+                             OK_Ordinary);
+  QualType ConstIdT = Context->getObjCIdType().withConst();
+  CStyleCastExpr * DictValueObjects = 
+    NoTypeInfoCStyleCastExpr(Context, 
+                             Context->getPointerType(ConstIdT),
+                             CK_BitCast,
+                             DictLiteralValueME);
+  // (const id <NSCopying> [])keys
+  Expr *NSKeyCallExpr = 
+    new (Context) CallExpr(*Context, NSDictDRE, KeyExprs,
+                           NSDictFType, VK_LValue, SourceLocation());
+  
+  MemberExpr *DictLiteralKeyME = 
+    new (Context) MemberExpr(NSKeyCallExpr, false, ARRFD, 
+                             SourceLocation(),
+                             ARRFD->getType(), VK_LValue,
+                             OK_Ordinary);
+  
+  CStyleCastExpr * DictKeyObjects = 
+    NoTypeInfoCStyleCastExpr(Context, 
+                             Context->getPointerType(ConstIdT),
+                             CK_BitCast,
+                             DictLiteralKeyME);
+  
+  
+  
+  // Synthesize a call to objc_msgSend().
+  SmallVector<Expr*, 32> MsgExprs;
+  SmallVector<Expr*, 4> ClsExprs;
+  QualType expType = Exp->getType();
+  
+  // Create a call to objc_getClass("NSArray"). It will be th 1st argument.
+  ObjCInterfaceDecl *Class = 
+  expType->getPointeeType()->getAs<ObjCObjectType>()->getInterface();
+  
+  IdentifierInfo *clsName = Class->getIdentifier();
+  ClsExprs.push_back(getStringLiteral(clsName->getName()));
+  CallExpr *Cls = SynthesizeCallToFunctionDecl(GetClassFunctionDecl,
+                                               &ClsExprs[0],
+                                               ClsExprs.size(), 
+                                               StartLoc, EndLoc);
+  MsgExprs.push_back(Cls);
+  
+  // Create a call to sel_registerName("arrayWithObjects:count:").
+  // it will be the 2nd argument.
+  SmallVector<Expr*, 4> SelExprs;
+  ObjCMethodDecl *DictMethod = Exp->getDictWithObjectsMethod();
+  SelExprs.push_back(getStringLiteral(DictMethod->getSelector().getAsString()));
+  CallExpr *SelExp = SynthesizeCallToFunctionDecl(SelGetUidFunctionDecl,
+                                                  &SelExprs[0], SelExprs.size(),
+                                                  StartLoc, EndLoc);
+  MsgExprs.push_back(SelExp);
+  
+  // (const id [])objects
+  MsgExprs.push_back(DictValueObjects);
+  
+  // (const id <NSCopying> [])keys
+  MsgExprs.push_back(DictKeyObjects);
+  
+  // (NSUInteger)cnt
+  Expr *cnt = IntegerLiteral::Create(*Context,
+                                     llvm::APInt(UnsignedIntSize, NumElements),
+                                     Context->UnsignedIntTy, SourceLocation());
+  MsgExprs.push_back(cnt);
+  
+  
+  SmallVector<QualType, 8> ArgTypes;
+  ArgTypes.push_back(Context->getObjCIdType());
+  ArgTypes.push_back(Context->getObjCSelType());
+  for (const auto *PI : DictMethod->params()) {
+    QualType T = PI->getType();
+    if (const PointerType* PT = T->getAs<PointerType>()) {
+      QualType PointeeTy = PT->getPointeeType();
+      convertToUnqualifiedObjCType(PointeeTy);
+      T = Context->getPointerType(PointeeTy);
+    }
+    ArgTypes.push_back(T);
+  }
+  
+  QualType returnType = Exp->getType();
+  // Get the type, we will need to reference it in a couple spots.
+  QualType msgSendType = MsgSendFlavor->getType();
+  
+  // Create a reference to the objc_msgSend() declaration.
+  DeclRefExpr *DRE = new (Context) DeclRefExpr(MsgSendFlavor, false, msgSendType,
+                                               VK_LValue, SourceLocation());
+  
+  CastExpr *cast = NoTypeInfoCStyleCastExpr(Context,
+                                            Context->getPointerType(Context->VoidTy),
+                                            CK_BitCast, DRE);
+  
+  // Now do the "normal" pointer to function cast.
+  QualType castType =
+  getSimpleFunctionType(returnType, ArgTypes, DictMethod->isVariadic());
+  castType = Context->getPointerType(castType);
+  cast = NoTypeInfoCStyleCastExpr(Context, castType, CK_BitCast,
+                                  cast);
+  
+  // Don't forget the parens to enforce the proper binding.
+  ParenExpr *PE = new (Context) ParenExpr(StartLoc, EndLoc, cast);
+  
+  const FunctionType *FT = msgSendType->getAs<FunctionType>();
+  CallExpr *CE = new (Context)
+      CallExpr(*Context, PE, MsgExprs, FT->getReturnType(), VK_RValue, EndLoc);
+  ReplaceStmt(Exp, CE);
+  return CE;
+}
+
+// struct __rw_objc_super { 
+//   struct objc_object *object; struct objc_object *superClass; 
+// };
+QualType RewriteModernObjC::getSuperStructType() {
+  if (!SuperStructDecl) {
+    SuperStructDecl = RecordDecl::Create(*Context, TTK_Struct, TUDecl,
+                                         SourceLocation(), SourceLocation(),
+                                         &Context->Idents.get("__rw_objc_super"));
+    QualType FieldTypes[2];
+
+    // struct objc_object *object;
+    FieldTypes[0] = Context->getObjCIdType();
+    // struct objc_object *superClass;
+    FieldTypes[1] = Context->getObjCIdType();
+
+    // Create fields
+    for (unsigned i = 0; i < 2; ++i) {
+      SuperStructDecl->addDecl(FieldDecl::Create(*Context, SuperStructDecl,
+                                                 SourceLocation(),
+                                                 SourceLocation(), nullptr,
+                                                 FieldTypes[i], nullptr,
+                                                 /*BitWidth=*/nullptr,
+                                                 /*Mutable=*/false,
+                                                 ICIS_NoInit));
+    }
+
+    SuperStructDecl->completeDefinition();
+  }
+  return Context->getTagDeclType(SuperStructDecl);
+}
+
+QualType RewriteModernObjC::getConstantStringStructType() {
+  if (!ConstantStringDecl) {
+    ConstantStringDecl = RecordDecl::Create(*Context, TTK_Struct, TUDecl,
+                                            SourceLocation(), SourceLocation(),
+                         &Context->Idents.get("__NSConstantStringImpl"));
+    QualType FieldTypes[4];
+
+    // struct objc_object *receiver;
+    FieldTypes[0] = Context->getObjCIdType();
+    // int flags;
+    FieldTypes[1] = Context->IntTy;
+    // char *str;
+    FieldTypes[2] = Context->getPointerType(Context->CharTy);
+    // long length;
+    FieldTypes[3] = Context->LongTy;
+
+    // Create fields
+    for (unsigned i = 0; i < 4; ++i) {
+      ConstantStringDecl->addDecl(FieldDecl::Create(*Context,
+                                                    ConstantStringDecl,
+                                                    SourceLocation(),
+                                                    SourceLocation(), nullptr,
+                                                    FieldTypes[i], nullptr,
+                                                    /*BitWidth=*/nullptr,
+                                                    /*Mutable=*/true,
+                                                    ICIS_NoInit));
+    }
+
+    ConstantStringDecl->completeDefinition();
+  }
+  return Context->getTagDeclType(ConstantStringDecl);
+}
+
+/// getFunctionSourceLocation - returns start location of a function
+/// definition. Complication arises when function has declared as
+/// extern "C" or extern "C" {...}
+static SourceLocation getFunctionSourceLocation (RewriteModernObjC &R,
+                                                 FunctionDecl *FD) {
+  if (FD->isExternC()  && !FD->isMain()) {
+    const DeclContext *DC = FD->getDeclContext();
+    if (const LinkageSpecDecl *LSD = dyn_cast<LinkageSpecDecl>(DC))
+      // if it is extern "C" {...}, return function decl's own location.
+      if (!LSD->getRBraceLoc().isValid())
+        return LSD->getExternLoc();
+  }
+  if (FD->getStorageClass() != SC_None)
+    R.RewriteBlockLiteralFunctionDecl(FD);
+  return FD->getTypeSpecStartLoc();
+}
+
+void RewriteModernObjC::RewriteLineDirective(const Decl *D) {
+  
+  SourceLocation Location = D->getLocation();
+  
+  if (Location.isFileID() && GenerateLineInfo) {
+    std::string LineString("\n#line ");
+    PresumedLoc PLoc = SM->getPresumedLoc(Location);
+    LineString += utostr(PLoc.getLine());
+    LineString += " \"";
+    LineString += Lexer::Stringify(PLoc.getFilename());
+    if (isa<ObjCMethodDecl>(D))
+      LineString += "\"";
+    else LineString += "\"\n";
+    
+    Location = D->getLocStart();
+    if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
+      if (FD->isExternC()  && !FD->isMain()) {
+        const DeclContext *DC = FD->getDeclContext();
+        if (const LinkageSpecDecl *LSD = dyn_cast<LinkageSpecDecl>(DC))
+          // if it is extern "C" {...}, return function decl's own location.
+          if (!LSD->getRBraceLoc().isValid())
+            Location = LSD->getExternLoc();
+      }
+    }
+    InsertText(Location, LineString);
+  }
+}
+
+/// SynthMsgSendStretCallExpr - This routine translates message expression
+/// into a call to objc_msgSend_stret() entry point. Tricky part is that
+/// nil check on receiver must be performed before calling objc_msgSend_stret.
+/// MsgSendStretFlavor - function declaration objc_msgSend_stret(...)
+/// msgSendType - function type of objc_msgSend_stret(...)
+/// returnType - Result type of the method being synthesized.
+/// ArgTypes - type of the arguments passed to objc_msgSend_stret, starting with receiver type.
+/// MsgExprs - list of argument expressions being passed to objc_msgSend_stret, 
+/// starting with receiver.
+/// Method - Method being rewritten.
+Expr *RewriteModernObjC::SynthMsgSendStretCallExpr(FunctionDecl *MsgSendStretFlavor,
+                                                 QualType returnType, 
+                                                 SmallVectorImpl<QualType> &ArgTypes,
+                                                 SmallVectorImpl<Expr*> &MsgExprs,
+                                                 ObjCMethodDecl *Method) {
+  // Now do the "normal" pointer to function cast.
+  QualType castType = getSimpleFunctionType(returnType, ArgTypes,
+                                            Method ? Method->isVariadic()
+                                                   : false);
+  castType = Context->getPointerType(castType);
+  
+  // build type for containing the objc_msgSend_stret object.
+  static unsigned stretCount=0;
+  std::string name = "__Stret"; name += utostr(stretCount);
+  std::string str = 
+    "extern \"C\" void * __cdecl memset(void *_Dst, int _Val, size_t _Size);\n";
+  str += "namespace {\n";
+  str += "struct "; str += name;
+  str += " {\n\t";
+  str += name;
+  str += "(id receiver, SEL sel";
+  for (unsigned i = 2; i < ArgTypes.size(); i++) {
+    std::string ArgName = "arg"; ArgName += utostr(i);
+    ArgTypes[i].getAsStringInternal(ArgName, Context->getPrintingPolicy());
+    str += ", "; str += ArgName;
+  }
+  // could be vararg.
+  for (unsigned i = ArgTypes.size(); i < MsgExprs.size(); i++) {
+    std::string ArgName = "arg"; ArgName += utostr(i);
+    MsgExprs[i]->getType().getAsStringInternal(ArgName,
+                                               Context->getPrintingPolicy());
+    str += ", "; str += ArgName;
+  }
+  
+  str += ") {\n";
+  str += "\t  unsigned size = sizeof(";
+  str += returnType.getAsString(Context->getPrintingPolicy()); str += ");\n";
+  
+  str += "\t  if (size == 1 || size == 2 || size == 4 || size == 8)\n";
+  
+  str += "\t    s = (("; str += castType.getAsString(Context->getPrintingPolicy());
+  str += ")(void *)objc_msgSend)(receiver, sel";
+  for (unsigned i = 2; i < ArgTypes.size(); i++) {
+    str += ", arg"; str += utostr(i);
+  }
+  // could be vararg.
+  for (unsigned i = ArgTypes.size(); i < MsgExprs.size(); i++) {
+    str += ", arg"; str += utostr(i);
+  }
+  str+= ");\n";
+  
+  str += "\t  else if (receiver == 0)\n";
+  str += "\t    memset((void*)&s, 0, sizeof(s));\n";
+  str += "\t  else\n";
+  
+  
+  str += "\t    s = (("; str += castType.getAsString(Context->getPrintingPolicy());
+  str += ")(void *)objc_msgSend_stret)(receiver, sel";
+  for (unsigned i = 2; i < ArgTypes.size(); i++) {
+    str += ", arg"; str += utostr(i);
+  }
+  // could be vararg.
+  for (unsigned i = ArgTypes.size(); i < MsgExprs.size(); i++) {
+    str += ", arg"; str += utostr(i);
+  }
+  str += ");\n";
+  
+  
+  str += "\t}\n";
+  str += "\t"; str += returnType.getAsString(Context->getPrintingPolicy());
+  str += " s;\n";
+  str += "};\n};\n\n";
+  SourceLocation FunLocStart;
+  if (CurFunctionDef)
+    FunLocStart = getFunctionSourceLocation(*this, CurFunctionDef);
+  else {
+    assert(CurMethodDef && "SynthMsgSendStretCallExpr - CurMethodDef is null");
+    FunLocStart = CurMethodDef->getLocStart();
+  }
+
+  InsertText(FunLocStart, str);
+  ++stretCount;
+  
+  // AST for __Stretn(receiver, args).s;
+  IdentifierInfo *ID = &Context->Idents.get(name);
+  FunctionDecl *FD = FunctionDecl::Create(*Context, TUDecl, SourceLocation(),
+                                          SourceLocation(), ID, castType,
+                                          nullptr, SC_Extern, false, false);
+  DeclRefExpr *DRE = new (Context) DeclRefExpr(FD, false, castType, VK_RValue,
+                                               SourceLocation());
+  CallExpr *STCE = new (Context) CallExpr(*Context, DRE, MsgExprs,
+                                          castType, VK_LValue, SourceLocation());
+
+  FieldDecl *FieldD = FieldDecl::Create(*Context, nullptr, SourceLocation(),
+                                    SourceLocation(),
+                                    &Context->Idents.get("s"),
+                                    returnType, nullptr,
+                                    /*BitWidth=*/nullptr,
+                                    /*Mutable=*/true, ICIS_NoInit);
+  MemberExpr *ME = new (Context) MemberExpr(STCE, false, FieldD, SourceLocation(),
+                                            FieldD->getType(), VK_LValue,
+                                            OK_Ordinary);
+
+  return ME;
+}
+
+Stmt *RewriteModernObjC::SynthMessageExpr(ObjCMessageExpr *Exp,
+                                    SourceLocation StartLoc,
+                                    SourceLocation EndLoc) {
+  if (!SelGetUidFunctionDecl)
+    SynthSelGetUidFunctionDecl();
+  if (!MsgSendFunctionDecl)
+    SynthMsgSendFunctionDecl();
+  if (!MsgSendSuperFunctionDecl)
+    SynthMsgSendSuperFunctionDecl();
+  if (!MsgSendStretFunctionDecl)
+    SynthMsgSendStretFunctionDecl();
+  if (!MsgSendSuperStretFunctionDecl)
+    SynthMsgSendSuperStretFunctionDecl();
+  if (!MsgSendFpretFunctionDecl)
+    SynthMsgSendFpretFunctionDecl();
+  if (!GetClassFunctionDecl)
+    SynthGetClassFunctionDecl();
+  if (!GetSuperClassFunctionDecl)
+    SynthGetSuperClassFunctionDecl();
+  if (!GetMetaClassFunctionDecl)
+    SynthGetMetaClassFunctionDecl();
+
+  // default to objc_msgSend().
+  FunctionDecl *MsgSendFlavor = MsgSendFunctionDecl;
+  // May need to use objc_msgSend_stret() as well.
+  FunctionDecl *MsgSendStretFlavor = nullptr;
+  if (ObjCMethodDecl *mDecl = Exp->getMethodDecl()) {
+    QualType resultType = mDecl->getReturnType();
+    if (resultType->isRecordType())
+      MsgSendStretFlavor = MsgSendStretFunctionDecl;
+    else if (resultType->isRealFloatingType())
+      MsgSendFlavor = MsgSendFpretFunctionDecl;
+  }
+
+  // Synthesize a call to objc_msgSend().
+  SmallVector<Expr*, 8> MsgExprs;
+  switch (Exp->getReceiverKind()) {
+  case ObjCMessageExpr::SuperClass: {
+    MsgSendFlavor = MsgSendSuperFunctionDecl;
+    if (MsgSendStretFlavor)
+      MsgSendStretFlavor = MsgSendSuperStretFunctionDecl;
+    assert(MsgSendFlavor && "MsgSendFlavor is NULL!");
+
+    ObjCInterfaceDecl *ClassDecl = CurMethodDef->getClassInterface();
+
+    SmallVector<Expr*, 4> InitExprs;
+
+    // set the receiver to self, the first argument to all methods.
+    InitExprs.push_back(
+      NoTypeInfoCStyleCastExpr(Context, Context->getObjCIdType(),
+                               CK_BitCast,
+                   new (Context) DeclRefExpr(CurMethodDef->getSelfDecl(),
+                                             false,
+                                             Context->getObjCIdType(),
+                                             VK_RValue,
+                                             SourceLocation()))
+                        ); // set the 'receiver'.
+
+    // (id)class_getSuperclass((Class)objc_getClass("CurrentClass"))
+    SmallVector<Expr*, 8> ClsExprs;
+    ClsExprs.push_back(getStringLiteral(ClassDecl->getIdentifier()->getName()));
+    // (Class)objc_getClass("CurrentClass")
+    CallExpr *Cls = SynthesizeCallToFunctionDecl(GetMetaClassFunctionDecl,
+                                                 &ClsExprs[0],
+                                                 ClsExprs.size(),
+                                                 StartLoc,
+                                                 EndLoc);
+    ClsExprs.clear();
+    ClsExprs.push_back(Cls);
+    Cls = SynthesizeCallToFunctionDecl(GetSuperClassFunctionDecl,
+                                       &ClsExprs[0], ClsExprs.size(),
+                                       StartLoc, EndLoc);
+    
+    // (id)class_getSuperclass((Class)objc_getClass("CurrentClass"))
+    // To turn off a warning, type-cast to 'id'
+    InitExprs.push_back( // set 'super class', using class_getSuperclass().
+                        NoTypeInfoCStyleCastExpr(Context,
+                                                 Context->getObjCIdType(),
+                                                 CK_BitCast, Cls));
+    // struct __rw_objc_super
+    QualType superType = getSuperStructType();
+    Expr *SuperRep;
+
+    if (LangOpts.MicrosoftExt) {
+      SynthSuperConstructorFunctionDecl();
+      // Simulate a constructor call...
+      DeclRefExpr *DRE = new (Context) DeclRefExpr(SuperConstructorFunctionDecl,
+                                                   false, superType, VK_LValue,
+                                                   SourceLocation());
+      SuperRep = new (Context) CallExpr(*Context, DRE, InitExprs,
+                                        superType, VK_LValue,
+                                        SourceLocation());
+      // The code for super is a little tricky to prevent collision with
+      // the structure definition in the header. The rewriter has it's own
+      // internal definition (__rw_objc_super) that is uses. This is why
+      // we need the cast below. For example:
+      // (struct __rw_objc_super *)&__rw_objc_super((id)self, (id)objc_getClass("SUPER"))
+      //
+      SuperRep = new (Context) UnaryOperator(SuperRep, UO_AddrOf,
+                               Context->getPointerType(SuperRep->getType()),
+                                             VK_RValue, OK_Ordinary,
+                                             SourceLocation());
+      SuperRep = NoTypeInfoCStyleCastExpr(Context,
+                                          Context->getPointerType(superType),
+                                          CK_BitCast, SuperRep);
+    } else {
+      // (struct __rw_objc_super) { <exprs from above> }
+      InitListExpr *ILE =
+        new (Context) InitListExpr(*Context, SourceLocation(), InitExprs,
+                                   SourceLocation());
+      TypeSourceInfo *superTInfo
+        = Context->getTrivialTypeSourceInfo(superType);
+      SuperRep = new (Context) CompoundLiteralExpr(SourceLocation(), superTInfo,
+                                                   superType, VK_LValue,
+                                                   ILE, false);
+      // struct __rw_objc_super *
+      SuperRep = new (Context) UnaryOperator(SuperRep, UO_AddrOf,
+                               Context->getPointerType(SuperRep->getType()),
+                                             VK_RValue, OK_Ordinary,
+                                             SourceLocation());
+    }
+    MsgExprs.push_back(SuperRep);
+    break;
+  }
+
+  case ObjCMessageExpr::Class: {
+    SmallVector<Expr*, 8> ClsExprs;
+    ObjCInterfaceDecl *Class
+      = Exp->getClassReceiver()->getAs<ObjCObjectType>()->getInterface();
+    IdentifierInfo *clsName = Class->getIdentifier();
+    ClsExprs.push_back(getStringLiteral(clsName->getName()));
+    CallExpr *Cls = SynthesizeCallToFunctionDecl(GetClassFunctionDecl,
+                                                 &ClsExprs[0],
+                                                 ClsExprs.size(), 
+                                                 StartLoc, EndLoc);
+    CastExpr *ArgExpr = NoTypeInfoCStyleCastExpr(Context,
+                                                 Context->getObjCIdType(),
+                                                 CK_BitCast, Cls);
+    MsgExprs.push_back(ArgExpr);
+    break;
+  }
+
+  case ObjCMessageExpr::SuperInstance:{
+    MsgSendFlavor = MsgSendSuperFunctionDecl;
+    if (MsgSendStretFlavor)
+      MsgSendStretFlavor = MsgSendSuperStretFunctionDecl;
+    assert(MsgSendFlavor && "MsgSendFlavor is NULL!");
+    ObjCInterfaceDecl *ClassDecl = CurMethodDef->getClassInterface();
+    SmallVector<Expr*, 4> InitExprs;
+
+    InitExprs.push_back(
+      NoTypeInfoCStyleCastExpr(Context, Context->getObjCIdType(),
+                               CK_BitCast,
+                   new (Context) DeclRefExpr(CurMethodDef->getSelfDecl(),
+                                             false,
+                                             Context->getObjCIdType(),
+                                             VK_RValue, SourceLocation()))
+                        ); // set the 'receiver'.
+    
+    // (id)class_getSuperclass((Class)objc_getClass("CurrentClass"))
+    SmallVector<Expr*, 8> ClsExprs;
+    ClsExprs.push_back(getStringLiteral(ClassDecl->getIdentifier()->getName()));
+    // (Class)objc_getClass("CurrentClass")
+    CallExpr *Cls = SynthesizeCallToFunctionDecl(GetClassFunctionDecl,
+                                                 &ClsExprs[0],
+                                                 ClsExprs.size(), 
+                                                 StartLoc, EndLoc);
+    ClsExprs.clear();
+    ClsExprs.push_back(Cls);
+    Cls = SynthesizeCallToFunctionDecl(GetSuperClassFunctionDecl,
+                                       &ClsExprs[0], ClsExprs.size(),
+                                       StartLoc, EndLoc);
+    
+    // (id)class_getSuperclass((Class)objc_getClass("CurrentClass"))
+    // To turn off a warning, type-cast to 'id'
+    InitExprs.push_back(
+      // set 'super class', using class_getSuperclass().
+      NoTypeInfoCStyleCastExpr(Context, Context->getObjCIdType(),
+                               CK_BitCast, Cls));
+    // struct __rw_objc_super
+    QualType superType = getSuperStructType();
+    Expr *SuperRep;
+
+    if (LangOpts.MicrosoftExt) {
+      SynthSuperConstructorFunctionDecl();
+      // Simulate a constructor call...
+      DeclRefExpr *DRE = new (Context) DeclRefExpr(SuperConstructorFunctionDecl,
+                                                   false, superType, VK_LValue,
+                                                   SourceLocation());
+      SuperRep = new (Context) CallExpr(*Context, DRE, InitExprs,
+                                        superType, VK_LValue, SourceLocation());
+      // The code for super is a little tricky to prevent collision with
+      // the structure definition in the header. The rewriter has it's own
+      // internal definition (__rw_objc_super) that is uses. This is why
+      // we need the cast below. For example:
+      // (struct __rw_objc_super *)&__rw_objc_super((id)self, (id)objc_getClass("SUPER"))
+      //
+      SuperRep = new (Context) UnaryOperator(SuperRep, UO_AddrOf,
+                               Context->getPointerType(SuperRep->getType()),
+                               VK_RValue, OK_Ordinary,
+                               SourceLocation());
+      SuperRep = NoTypeInfoCStyleCastExpr(Context,
+                               Context->getPointerType(superType),
+                               CK_BitCast, SuperRep);
+    } else {
+      // (struct __rw_objc_super) { <exprs from above> }
+      InitListExpr *ILE =
+        new (Context) InitListExpr(*Context, SourceLocation(), InitExprs,
+                                   SourceLocation());
+      TypeSourceInfo *superTInfo
+        = Context->getTrivialTypeSourceInfo(superType);
+      SuperRep = new (Context) CompoundLiteralExpr(SourceLocation(), superTInfo,
+                                                   superType, VK_RValue, ILE,
+                                                   false);
+    }
+    MsgExprs.push_back(SuperRep);
+    break;
+  }
+
+  case ObjCMessageExpr::Instance: {
+    // Remove all type-casts because it may contain objc-style types; e.g.
+    // Foo<Proto> *.
+    Expr *recExpr = Exp->getInstanceReceiver();
+    while (CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(recExpr))
+      recExpr = CE->getSubExpr();
+    CastKind CK = recExpr->getType()->isObjCObjectPointerType()
+                    ? CK_BitCast : recExpr->getType()->isBlockPointerType()
+                                     ? CK_BlockPointerToObjCPointerCast
+                                     : CK_CPointerToObjCPointerCast;
+
+    recExpr = NoTypeInfoCStyleCastExpr(Context, Context->getObjCIdType(),
+                                       CK, recExpr);
+    MsgExprs.push_back(recExpr);
+    break;
+  }
+  }
+
+  // Create a call to sel_registerName("selName"), it will be the 2nd argument.
+  SmallVector<Expr*, 8> SelExprs;
+  SelExprs.push_back(getStringLiteral(Exp->getSelector().getAsString()));
+  CallExpr *SelExp = SynthesizeCallToFunctionDecl(SelGetUidFunctionDecl,
+                                                 &SelExprs[0], SelExprs.size(),
+                                                  StartLoc,
+                                                  EndLoc);
+  MsgExprs.push_back(SelExp);
+
+  // Now push any user supplied arguments.
+  for (unsigned i = 0; i < Exp->getNumArgs(); i++) {
+    Expr *userExpr = Exp->getArg(i);
+    // Make all implicit casts explicit...ICE comes in handy:-)
+    if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(userExpr)) {
+      // Reuse the ICE type, it is exactly what the doctor ordered.
+      QualType type = ICE->getType();
+      if (needToScanForQualifiers(type))
+        type = Context->getObjCIdType();
+      // Make sure we convert "type (^)(...)" to "type (*)(...)".
+      (void)convertBlockPointerToFunctionPointer(type);
+      const Expr *SubExpr = ICE->IgnoreParenImpCasts();
+      CastKind CK;
+      if (SubExpr->getType()->isIntegralType(*Context) && 
+          type->isBooleanType()) {
+        CK = CK_IntegralToBoolean;
+      } else if (type->isObjCObjectPointerType()) {
+        if (SubExpr->getType()->isBlockPointerType()) {
+          CK = CK_BlockPointerToObjCPointerCast;
+        } else if (SubExpr->getType()->isPointerType()) {
+          CK = CK_CPointerToObjCPointerCast;
+        } else {
+          CK = CK_BitCast;
+        }
+      } else {
+        CK = CK_BitCast;
+      }
+
+      userExpr = NoTypeInfoCStyleCastExpr(Context, type, CK, userExpr);
+    }
+    // Make id<P...> cast into an 'id' cast.
+    else if (CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(userExpr)) {
+      if (CE->getType()->isObjCQualifiedIdType()) {
+        while ((CE = dyn_cast<CStyleCastExpr>(userExpr)))
+          userExpr = CE->getSubExpr();
+        CastKind CK;
+        if (userExpr->getType()->isIntegralType(*Context)) {
+          CK = CK_IntegralToPointer;
+        } else if (userExpr->getType()->isBlockPointerType()) {
+          CK = CK_BlockPointerToObjCPointerCast;
+        } else if (userExpr->getType()->isPointerType()) {
+          CK = CK_CPointerToObjCPointerCast;
+        } else {
+          CK = CK_BitCast;
+        }
+        userExpr = NoTypeInfoCStyleCastExpr(Context, Context->getObjCIdType(),
+                                            CK, userExpr);
+      }
+    }
+    MsgExprs.push_back(userExpr);
+    // We've transferred the ownership to MsgExprs. For now, we *don't* null
+    // out the argument in the original expression (since we aren't deleting
+    // the ObjCMessageExpr). See RewritePropertyOrImplicitSetter() usage for more info.
+    //Exp->setArg(i, 0);
+  }
+  // Generate the funky cast.
+  CastExpr *cast;
+  SmallVector<QualType, 8> ArgTypes;
+  QualType returnType;
+
+  // Push 'id' and 'SEL', the 2 implicit arguments.
+  if (MsgSendFlavor == MsgSendSuperFunctionDecl)
+    ArgTypes.push_back(Context->getPointerType(getSuperStructType()));
+  else
+    ArgTypes.push_back(Context->getObjCIdType());
+  ArgTypes.push_back(Context->getObjCSelType());
+  if (ObjCMethodDecl *OMD = Exp->getMethodDecl()) {
+    // Push any user argument types.
+    for (const auto *PI : OMD->params()) {
+      QualType t = PI->getType()->isObjCQualifiedIdType()
+                     ? Context->getObjCIdType()
+                     : PI->getType();
+      // Make sure we convert "t (^)(...)" to "t (*)(...)".
+      (void)convertBlockPointerToFunctionPointer(t);
+      ArgTypes.push_back(t);
+    }
+    returnType = Exp->getType();
+    convertToUnqualifiedObjCType(returnType);
+    (void)convertBlockPointerToFunctionPointer(returnType);
+  } else {
+    returnType = Context->getObjCIdType();
+  }
+  // Get the type, we will need to reference it in a couple spots.
+  QualType msgSendType = MsgSendFlavor->getType();
+
+  // Create a reference to the objc_msgSend() declaration.
+  DeclRefExpr *DRE = new (Context) DeclRefExpr(MsgSendFlavor, false, msgSendType,
+                                               VK_LValue, SourceLocation());
+
+  // Need to cast objc_msgSend to "void *" (to workaround a GCC bandaid).
+  // If we don't do this cast, we get the following bizarre warning/note:
+  // xx.m:13: warning: function called through a non-compatible type
+  // xx.m:13: note: if this code is reached, the program will abort
+  cast = NoTypeInfoCStyleCastExpr(Context,
+                                  Context->getPointerType(Context->VoidTy),
+                                  CK_BitCast, DRE);
+
+  // Now do the "normal" pointer to function cast.
+  // If we don't have a method decl, force a variadic cast.
+  const ObjCMethodDecl *MD = Exp->getMethodDecl();
+  QualType castType =
+    getSimpleFunctionType(returnType, ArgTypes, MD ? MD->isVariadic() : true);
+  castType = Context->getPointerType(castType);
+  cast = NoTypeInfoCStyleCastExpr(Context, castType, CK_BitCast,
+                                  cast);
+
+  // Don't forget the parens to enforce the proper binding.
+  ParenExpr *PE = new (Context) ParenExpr(StartLoc, EndLoc, cast);
+
+  const FunctionType *FT = msgSendType->getAs<FunctionType>();
+  CallExpr *CE = new (Context)
+      CallExpr(*Context, PE, MsgExprs, FT->getReturnType(), VK_RValue, EndLoc);
+  Stmt *ReplacingStmt = CE;
+  if (MsgSendStretFlavor) {
+    // We have the method which returns a struct/union. Must also generate
+    // call to objc_msgSend_stret and hang both varieties on a conditional
+    // expression which dictate which one to envoke depending on size of
+    // method's return type.
+
+    Expr *STCE = SynthMsgSendStretCallExpr(MsgSendStretFlavor,
+                                           returnType,
+                                           ArgTypes, MsgExprs,
+                                           Exp->getMethodDecl());
+    ReplacingStmt = STCE;
+  }
+  // delete Exp; leak for now, see RewritePropertyOrImplicitSetter() usage for more info.
+  return ReplacingStmt;
+}
+
+Stmt *RewriteModernObjC::RewriteMessageExpr(ObjCMessageExpr *Exp) {
+  Stmt *ReplacingStmt = SynthMessageExpr(Exp, Exp->getLocStart(),
+                                         Exp->getLocEnd());
+
+  // Now do the actual rewrite.
+  ReplaceStmt(Exp, ReplacingStmt);
+
+  // delete Exp; leak for now, see RewritePropertyOrImplicitSetter() usage for more info.
+  return ReplacingStmt;
+}
+
+// typedef struct objc_object Protocol;
+QualType RewriteModernObjC::getProtocolType() {
+  if (!ProtocolTypeDecl) {
+    TypeSourceInfo *TInfo
+      = Context->getTrivialTypeSourceInfo(Context->getObjCIdType());
+    ProtocolTypeDecl = TypedefDecl::Create(*Context, TUDecl,
+                                           SourceLocation(), SourceLocation(),
+                                           &Context->Idents.get("Protocol"),
+                                           TInfo);
+  }
+  return Context->getTypeDeclType(ProtocolTypeDecl);
+}
+
+/// RewriteObjCProtocolExpr - Rewrite a protocol expression into
+/// a synthesized/forward data reference (to the protocol's metadata).
+/// The forward references (and metadata) are generated in
+/// RewriteModernObjC::HandleTranslationUnit().
+Stmt *RewriteModernObjC::RewriteObjCProtocolExpr(ObjCProtocolExpr *Exp) {
+  std::string Name = "_OBJC_PROTOCOL_REFERENCE_$_" + 
+                      Exp->getProtocol()->getNameAsString();
+  IdentifierInfo *ID = &Context->Idents.get(Name);
+  VarDecl *VD = VarDecl::Create(*Context, TUDecl, SourceLocation(),
+                                SourceLocation(), ID, getProtocolType(),
+                                nullptr, SC_Extern);
+  DeclRefExpr *DRE = new (Context) DeclRefExpr(VD, false, getProtocolType(),
+                                               VK_LValue, SourceLocation());
+  CastExpr *castExpr =
+    NoTypeInfoCStyleCastExpr(
+      Context, Context->getPointerType(DRE->getType()), CK_BitCast, DRE);
+  ReplaceStmt(Exp, castExpr);
+  ProtocolExprDecls.insert(Exp->getProtocol()->getCanonicalDecl());
+  // delete Exp; leak for now, see RewritePropertyOrImplicitSetter() usage for more info.
+  return castExpr;
+
+}
+
+bool RewriteModernObjC::BufferContainsPPDirectives(const char *startBuf,
+                                             const char *endBuf) {
+  while (startBuf < endBuf) {
+    if (*startBuf == '#') {
+      // Skip whitespace.
+      for (++startBuf; startBuf[0] == ' ' || startBuf[0] == '\t'; ++startBuf)
+        ;
+      if (!strncmp(startBuf, "if", strlen("if")) ||
+          !strncmp(startBuf, "ifdef", strlen("ifdef")) ||
+          !strncmp(startBuf, "ifndef", strlen("ifndef")) ||
+          !strncmp(startBuf, "define", strlen("define")) ||
+          !strncmp(startBuf, "undef", strlen("undef")) ||
+          !strncmp(startBuf, "else", strlen("else")) ||
+          !strncmp(startBuf, "elif", strlen("elif")) ||
+          !strncmp(startBuf, "endif", strlen("endif")) ||
+          !strncmp(startBuf, "pragma", strlen("pragma")) ||
+          !strncmp(startBuf, "include", strlen("include")) ||
+          !strncmp(startBuf, "import", strlen("import")) ||
+          !strncmp(startBuf, "include_next", strlen("include_next")))
+        return true;
+    }
+    startBuf++;
+  }
+  return false;
+}
+
+/// IsTagDefinedInsideClass - This routine checks that a named tagged type 
+/// is defined inside an objective-c class. If so, it returns true. 
+bool RewriteModernObjC::IsTagDefinedInsideClass(ObjCContainerDecl *IDecl, 
+                                                TagDecl *Tag,
+                                                bool &IsNamedDefinition) {
+  if (!IDecl)
+    return false;
+  SourceLocation TagLocation;
+  if (RecordDecl *RD = dyn_cast<RecordDecl>(Tag)) {
+    RD = RD->getDefinition();
+    if (!RD || !RD->getDeclName().getAsIdentifierInfo())
+      return false;
+    IsNamedDefinition = true;
+    TagLocation = RD->getLocation();
+    return Context->getSourceManager().isBeforeInTranslationUnit(
+                                          IDecl->getLocation(), TagLocation);
+  }
+  if (EnumDecl *ED = dyn_cast<EnumDecl>(Tag)) {
+    if (!ED || !ED->getDeclName().getAsIdentifierInfo())
+      return false;
+    IsNamedDefinition = true;
+    TagLocation = ED->getLocation();
+    return Context->getSourceManager().isBeforeInTranslationUnit(
+                                          IDecl->getLocation(), TagLocation);
+
+  }
+  return false;
+}
+
+/// RewriteObjCFieldDeclType - This routine rewrites a type into the buffer.
+/// It handles elaborated types, as well as enum types in the process.
+bool RewriteModernObjC::RewriteObjCFieldDeclType(QualType &Type, 
+                                                 std::string &Result) {
+  if (isa<TypedefType>(Type)) {
+    Result += "\t";
+    return false;
+  }
+    
+  if (Type->isArrayType()) {
+    QualType ElemTy = Context->getBaseElementType(Type);
+    return RewriteObjCFieldDeclType(ElemTy, Result);
+  }
+  else if (Type->isRecordType()) {
+    RecordDecl *RD = Type->getAs<RecordType>()->getDecl();
+    if (RD->isCompleteDefinition()) {
+      if (RD->isStruct())
+        Result += "\n\tstruct ";
+      else if (RD->isUnion())
+        Result += "\n\tunion ";
+      else
+        assert(false && "class not allowed as an ivar type");
+      
+      Result += RD->getName();
+      if (GlobalDefinedTags.count(RD)) {
+        // struct/union is defined globally, use it.
+        Result += " ";
+        return true;
+      }
+      Result += " {\n";
+      for (auto *FD : RD->fields())
+        RewriteObjCFieldDecl(FD, Result);
+      Result += "\t} "; 
+      return true;
+    }
+  }
+  else if (Type->isEnumeralType()) {
+    EnumDecl *ED = Type->getAs<EnumType>()->getDecl();
+    if (ED->isCompleteDefinition()) {
+      Result += "\n\tenum ";
+      Result += ED->getName();
+      if (GlobalDefinedTags.count(ED)) {
+        // Enum is globall defined, use it.
+        Result += " ";
+        return true;
+      }
+      
+      Result += " {\n";
+      for (const auto *EC : ED->enumerators()) {
+        Result += "\t"; Result += EC->getName(); Result += " = ";
+        llvm::APSInt Val = EC->getInitVal();
+        Result += Val.toString(10);
+        Result += ",\n";
+      }
+      Result += "\t} "; 
+      return true;
+    }
+  }
+  
+  Result += "\t";
+  convertObjCTypeToCStyleType(Type);
+  return false;
+}
+
+
+/// RewriteObjCFieldDecl - This routine rewrites a field into the buffer.
+/// It handles elaborated types, as well as enum types in the process.
+void RewriteModernObjC::RewriteObjCFieldDecl(FieldDecl *fieldDecl, 
+                                             std::string &Result) {
+  QualType Type = fieldDecl->getType();
+  std::string Name = fieldDecl->getNameAsString();
+  
+  bool EleboratedType = RewriteObjCFieldDeclType(Type, Result); 
+  if (!EleboratedType)
+    Type.getAsStringInternal(Name, Context->getPrintingPolicy());
+  Result += Name;
+  if (fieldDecl->isBitField()) {
+    Result += " : "; Result += utostr(fieldDecl->getBitWidthValue(*Context));
+  }
+  else if (EleboratedType && Type->isArrayType()) {
+    const ArrayType *AT = Context->getAsArrayType(Type);
+    do {
+      if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(AT)) {
+        Result += "[";
+        llvm::APInt Dim = CAT->getSize();
+        Result += utostr(Dim.getZExtValue());
+        Result += "]";
+      }
+      AT = Context->getAsArrayType(AT->getElementType());
+    } while (AT);
+  }
+  
+  Result += ";\n";
+}
+
+/// RewriteLocallyDefinedNamedAggregates - This routine rewrites locally defined
+/// named aggregate types into the input buffer.
+void RewriteModernObjC::RewriteLocallyDefinedNamedAggregates(FieldDecl *fieldDecl, 
+                                             std::string &Result) {
+  QualType Type = fieldDecl->getType();
+  if (isa<TypedefType>(Type))
+    return;
+  if (Type->isArrayType())
+    Type = Context->getBaseElementType(Type);
+  ObjCContainerDecl *IDecl = 
+    dyn_cast<ObjCContainerDecl>(fieldDecl->getDeclContext());
+
+  TagDecl *TD = nullptr;
+  if (Type->isRecordType()) {
+    TD = Type->getAs<RecordType>()->getDecl();
+  }
+  else if (Type->isEnumeralType()) {
+    TD = Type->getAs<EnumType>()->getDecl();
+  }
+  
+  if (TD) {
+    if (GlobalDefinedTags.count(TD))
+      return;
+    
+    bool IsNamedDefinition = false;
+    if (IsTagDefinedInsideClass(IDecl, TD, IsNamedDefinition)) {
+      RewriteObjCFieldDeclType(Type, Result);
+      Result += ";";
+    }
+    if (IsNamedDefinition)
+      GlobalDefinedTags.insert(TD);
+  }
+    
+}
+
+unsigned RewriteModernObjC::ObjCIvarBitfieldGroupNo(ObjCIvarDecl *IV) {
+  const ObjCInterfaceDecl *CDecl = IV->getContainingInterface();
+  if (ObjCInterefaceHasBitfieldGroups.count(CDecl)) {
+    return IvarGroupNumber[IV];
+  }
+  unsigned GroupNo = 0;
+  SmallVector<const ObjCIvarDecl *, 8> IVars;
+  for (const ObjCIvarDecl *IVD = CDecl->all_declared_ivar_begin();
+       IVD; IVD = IVD->getNextIvar())
+    IVars.push_back(IVD);
+  
+  for (unsigned i = 0, e = IVars.size(); i < e; i++)
+    if (IVars[i]->isBitField()) {
+      IvarGroupNumber[IVars[i++]] = ++GroupNo;
+      while (i < e && IVars[i]->isBitField())
+        IvarGroupNumber[IVars[i++]] = GroupNo;
+      if (i < e)
+        --i;
+    }
+
+  ObjCInterefaceHasBitfieldGroups.insert(CDecl);
+  return IvarGroupNumber[IV];
+}
+
+QualType RewriteModernObjC::SynthesizeBitfieldGroupStructType(
+                              ObjCIvarDecl *IV,
+                              SmallVectorImpl<ObjCIvarDecl *> &IVars) {
+  std::string StructTagName;
+  ObjCIvarBitfieldGroupType(IV, StructTagName);
+  RecordDecl *RD = RecordDecl::Create(*Context, TTK_Struct,
+                                      Context->getTranslationUnitDecl(),
+                                      SourceLocation(), SourceLocation(),
+                                      &Context->Idents.get(StructTagName));
+  for (unsigned i=0, e = IVars.size(); i < e; i++) {
+    ObjCIvarDecl *Ivar = IVars[i];
+    RD->addDecl(FieldDecl::Create(*Context, RD, SourceLocation(), SourceLocation(),
+                                  &Context->Idents.get(Ivar->getName()),
+                                  Ivar->getType(),
+                                  nullptr, /*Expr *BW */Ivar->getBitWidth(),
+                                  false, ICIS_NoInit));
+  }
+  RD->completeDefinition();
+  return Context->getTagDeclType(RD);
+}
+
+QualType RewriteModernObjC::GetGroupRecordTypeForObjCIvarBitfield(ObjCIvarDecl *IV) {
+  const ObjCInterfaceDecl *CDecl = IV->getContainingInterface();
+  unsigned GroupNo = ObjCIvarBitfieldGroupNo(IV);
+  std::pair<const ObjCInterfaceDecl*, unsigned> tuple = std::make_pair(CDecl, GroupNo);
+  if (GroupRecordType.count(tuple))
+    return GroupRecordType[tuple];
+  
+  SmallVector<ObjCIvarDecl *, 8> IVars;
+  for (const ObjCIvarDecl *IVD = CDecl->all_declared_ivar_begin();
+       IVD; IVD = IVD->getNextIvar()) {
+    if (IVD->isBitField())
+      IVars.push_back(const_cast<ObjCIvarDecl *>(IVD));
+    else {
+      if (!IVars.empty()) {
+        unsigned GroupNo = ObjCIvarBitfieldGroupNo(IVars[0]);
+        // Generate the struct type for this group of bitfield ivars.
+        GroupRecordType[std::make_pair(CDecl, GroupNo)] =
+          SynthesizeBitfieldGroupStructType(IVars[0], IVars);
+        IVars.clear();
+      }
+    }
+  }
+  if (!IVars.empty()) {
+    // Do the last one.
+    unsigned GroupNo = ObjCIvarBitfieldGroupNo(IVars[0]);
+    GroupRecordType[std::make_pair(CDecl, GroupNo)] =
+      SynthesizeBitfieldGroupStructType(IVars[0], IVars);
+  }
+  QualType RetQT = GroupRecordType[tuple];
+  assert(!RetQT.isNull() && "GetGroupRecordTypeForObjCIvarBitfield struct type is NULL");
+  
+  return RetQT;
+}
+
+/// ObjCIvarBitfieldGroupDecl - Names field decl. for ivar bitfield group.
+/// Name would be: classname__GRBF_n where n is the group number for this ivar.
+void RewriteModernObjC::ObjCIvarBitfieldGroupDecl(ObjCIvarDecl *IV,
+                                                  std::string &Result) {
+  const ObjCInterfaceDecl *CDecl = IV->getContainingInterface();
+  Result += CDecl->getName();
+  Result += "__GRBF_";
+  unsigned GroupNo = ObjCIvarBitfieldGroupNo(IV);
+  Result += utostr(GroupNo);
+  return;
+}
+
+/// ObjCIvarBitfieldGroupType - Names struct type for ivar bitfield group.
+/// Name of the struct would be: classname__T_n where n is the group number for
+/// this ivar.
+void RewriteModernObjC::ObjCIvarBitfieldGroupType(ObjCIvarDecl *IV,
+                                                  std::string &Result) {
+  const ObjCInterfaceDecl *CDecl = IV->getContainingInterface();
+  Result += CDecl->getName();
+  Result += "__T_";
+  unsigned GroupNo = ObjCIvarBitfieldGroupNo(IV);
+  Result += utostr(GroupNo);
+  return;
+}
+
+/// ObjCIvarBitfieldGroupOffset - Names symbol for ivar bitfield group field offset.
+/// Name would be: OBJC_IVAR_$_classname__GRBF_n where n is the group number for
+/// this ivar.
+void RewriteModernObjC::ObjCIvarBitfieldGroupOffset(ObjCIvarDecl *IV,
+                                                    std::string &Result) {
+  Result += "OBJC_IVAR_$_";
+  ObjCIvarBitfieldGroupDecl(IV, Result);
+}
+
+#define SKIP_BITFIELDS(IX, ENDIX, VEC) { \
+      while ((IX < ENDIX) && VEC[IX]->isBitField()) \
+        ++IX; \
+      if (IX < ENDIX) \
+        --IX; \
+}
+
+/// RewriteObjCInternalStruct - Rewrite one internal struct corresponding to
+/// an objective-c class with ivars.
+void RewriteModernObjC::RewriteObjCInternalStruct(ObjCInterfaceDecl *CDecl,
+                                               std::string &Result) {
+  assert(CDecl && "Class missing in SynthesizeObjCInternalStruct");
+  assert(CDecl->getName() != "" &&
+         "Name missing in SynthesizeObjCInternalStruct");
+  ObjCInterfaceDecl *RCDecl = CDecl->getSuperClass();
+  SmallVector<ObjCIvarDecl *, 8> IVars;
+  for (ObjCIvarDecl *IVD = CDecl->all_declared_ivar_begin();
+       IVD; IVD = IVD->getNextIvar())
+    IVars.push_back(IVD);
+  
+  SourceLocation LocStart = CDecl->getLocStart();
+  SourceLocation LocEnd = CDecl->getEndOfDefinitionLoc();
+  
+  const char *startBuf = SM->getCharacterData(LocStart);
+  const char *endBuf = SM->getCharacterData(LocEnd);
+  
+  // If no ivars and no root or if its root, directly or indirectly,
+  // have no ivars (thus not synthesized) then no need to synthesize this class.
+  if ((!CDecl->isThisDeclarationADefinition() || IVars.size() == 0) &&
+      (!RCDecl || !ObjCSynthesizedStructs.count(RCDecl))) {
+    endBuf += Lexer::MeasureTokenLength(LocEnd, *SM, LangOpts);
+    ReplaceText(LocStart, endBuf-startBuf, Result);
+    return;
+  }
+  
+  // Insert named struct/union definitions inside class to
+  // outer scope. This follows semantics of locally defined
+  // struct/unions in objective-c classes.
+  for (unsigned i = 0, e = IVars.size(); i < e; i++)
+    RewriteLocallyDefinedNamedAggregates(IVars[i], Result);
+  
+  // Insert named structs which are syntheized to group ivar bitfields
+  // to outer scope as well.
+  for (unsigned i = 0, e = IVars.size(); i < e; i++)
+    if (IVars[i]->isBitField()) {
+      ObjCIvarDecl *IV = IVars[i];
+      QualType QT = GetGroupRecordTypeForObjCIvarBitfield(IV);
+      RewriteObjCFieldDeclType(QT, Result);
+      Result += ";";
+      // skip over ivar bitfields in this group.
+      SKIP_BITFIELDS(i , e, IVars);
+    }
+    
+  Result += "\nstruct ";
+  Result += CDecl->getNameAsString();
+  Result += "_IMPL {\n";
+  
+  if (RCDecl && ObjCSynthesizedStructs.count(RCDecl)) {
+    Result += "\tstruct "; Result += RCDecl->getNameAsString();
+    Result += "_IMPL "; Result += RCDecl->getNameAsString();
+    Result += "_IVARS;\n";
+  }
+  
+  for (unsigned i = 0, e = IVars.size(); i < e; i++) {
+    if (IVars[i]->isBitField()) {
+      ObjCIvarDecl *IV = IVars[i];
+      Result += "\tstruct ";
+      ObjCIvarBitfieldGroupType(IV, Result); Result += " ";
+      ObjCIvarBitfieldGroupDecl(IV, Result); Result += ";\n";
+      // skip over ivar bitfields in this group.
+      SKIP_BITFIELDS(i , e, IVars);
+    }
+    else
+      RewriteObjCFieldDecl(IVars[i], Result);
+  }
+
+  Result += "};\n";
+  endBuf += Lexer::MeasureTokenLength(LocEnd, *SM, LangOpts);
+  ReplaceText(LocStart, endBuf-startBuf, Result);
+  // Mark this struct as having been generated.
+  if (!ObjCSynthesizedStructs.insert(CDecl))
+    llvm_unreachable("struct already synthesize- RewriteObjCInternalStruct");
+}
+
+/// RewriteIvarOffsetSymbols - Rewrite ivar offset symbols of those ivars which
+/// have been referenced in an ivar access expression.
+void RewriteModernObjC::RewriteIvarOffsetSymbols(ObjCInterfaceDecl *CDecl,
+                                                  std::string &Result) {
+  // write out ivar offset symbols which have been referenced in an ivar
+  // access expression.
+  llvm::SmallPtrSet<ObjCIvarDecl *, 8> Ivars = ReferencedIvars[CDecl];
+  if (Ivars.empty())
+    return;
+  
+  llvm::DenseSet<std::pair<const ObjCInterfaceDecl*, unsigned> > GroupSymbolOutput;
+  for (llvm::SmallPtrSet<ObjCIvarDecl *, 8>::iterator i = Ivars.begin(),
+       e = Ivars.end(); i != e; i++) {
+    ObjCIvarDecl *IvarDecl = (*i);
+    const ObjCInterfaceDecl *IDecl = IvarDecl->getContainingInterface();
+    unsigned GroupNo = 0;
+    if (IvarDecl->isBitField()) {
+      GroupNo = ObjCIvarBitfieldGroupNo(IvarDecl);
+      if (GroupSymbolOutput.count(std::make_pair(IDecl, GroupNo)))
+        continue;
+    }
+    Result += "\n";
+    if (LangOpts.MicrosoftExt)
+      Result += "__declspec(allocate(\".objc_ivar$B\")) ";
+    Result += "extern \"C\" ";
+    if (LangOpts.MicrosoftExt && 
+        IvarDecl->getAccessControl() != ObjCIvarDecl::Private &&
+        IvarDecl->getAccessControl() != ObjCIvarDecl::Package)
+        Result += "__declspec(dllimport) ";
+
+    Result += "unsigned long ";
+    if (IvarDecl->isBitField()) {
+      ObjCIvarBitfieldGroupOffset(IvarDecl, Result);
+      GroupSymbolOutput.insert(std::make_pair(IDecl, GroupNo));
+    }
+    else
+      WriteInternalIvarName(CDecl, IvarDecl, Result);
+    Result += ";";
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// Meta Data Emission
+//===----------------------------------------------------------------------===//
+
+
+/// RewriteImplementations - This routine rewrites all method implementations
+/// and emits meta-data.
+
+void RewriteModernObjC::RewriteImplementations() {
+  int ClsDefCount = ClassImplementation.size();
+  int CatDefCount = CategoryImplementation.size();
+
+  // Rewrite implemented methods
+  for (int i = 0; i < ClsDefCount; i++) {
+    ObjCImplementationDecl *OIMP = ClassImplementation[i];
+    ObjCInterfaceDecl *CDecl = OIMP->getClassInterface();
+    if (CDecl->isImplicitInterfaceDecl())
+      assert(false &&
+             "Legacy implicit interface rewriting not supported in moder abi");
+    RewriteImplementationDecl(OIMP);
+  }
+
+  for (int i = 0; i < CatDefCount; i++) {
+    ObjCCategoryImplDecl *CIMP = CategoryImplementation[i];
+    ObjCInterfaceDecl *CDecl = CIMP->getClassInterface();
+    if (CDecl->isImplicitInterfaceDecl())
+      assert(false &&
+             "Legacy implicit interface rewriting not supported in moder abi");
+    RewriteImplementationDecl(CIMP);
+  }
+}
+
+void RewriteModernObjC::RewriteByRefString(std::string &ResultStr, 
+                                     const std::string &Name,
+                                     ValueDecl *VD, bool def) {
+  assert(BlockByRefDeclNo.count(VD) && 
+         "RewriteByRefString: ByRef decl missing");
+  if (def)
+    ResultStr += "struct ";
+  ResultStr += "__Block_byref_" + Name + 
+    "_" + utostr(BlockByRefDeclNo[VD]) ;
+}
+
+static bool HasLocalVariableExternalStorage(ValueDecl *VD) {
+  if (VarDecl *Var = dyn_cast<VarDecl>(VD))
+    return (Var->isFunctionOrMethodVarDecl() && !Var->hasLocalStorage());
+  return false;
+}
+
+std::string RewriteModernObjC::SynthesizeBlockFunc(BlockExpr *CE, int i,
+                                                   StringRef funcName,
+                                                   std::string Tag) {
+  const FunctionType *AFT = CE->getFunctionType();
+  QualType RT = AFT->getReturnType();
+  std::string StructRef = "struct " + Tag;
+  SourceLocation BlockLoc = CE->getExprLoc();
+  std::string S;
+  ConvertSourceLocationToLineDirective(BlockLoc, S);
+  
+  S += "static " + RT.getAsString(Context->getPrintingPolicy()) + " __" +
+         funcName.str() + "_block_func_" + utostr(i);
+
+  BlockDecl *BD = CE->getBlockDecl();
+
+  if (isa<FunctionNoProtoType>(AFT)) {
+    // No user-supplied arguments. Still need to pass in a pointer to the
+    // block (to reference imported block decl refs).
+    S += "(" + StructRef + " *__cself)";
+  } else if (BD->param_empty()) {
+    S += "(" + StructRef + " *__cself)";
+  } else {
+    const FunctionProtoType *FT = cast<FunctionProtoType>(AFT);
+    assert(FT && "SynthesizeBlockFunc: No function proto");
+    S += '(';
+    // first add the implicit argument.
+    S += StructRef + " *__cself, ";
+    std::string ParamStr;
+    for (BlockDecl::param_iterator AI = BD->param_begin(),
+         E = BD->param_end(); AI != E; ++AI) {
+      if (AI != BD->param_begin()) S += ", ";
+      ParamStr = (*AI)->getNameAsString();
+      QualType QT = (*AI)->getType();
+      (void)convertBlockPointerToFunctionPointer(QT);
+      QT.getAsStringInternal(ParamStr, Context->getPrintingPolicy());
+      S += ParamStr;
+    }
+    if (FT->isVariadic()) {
+      if (!BD->param_empty()) S += ", ";
+      S += "...";
+    }
+    S += ')';
+  }
+  S += " {\n";
+
+  // Create local declarations to avoid rewriting all closure decl ref exprs.
+  // First, emit a declaration for all "by ref" decls.
+  for (SmallVectorImpl<ValueDecl *>::iterator I = BlockByRefDecls.begin(),
+       E = BlockByRefDecls.end(); I != E; ++I) {
+    S += "  ";
+    std::string Name = (*I)->getNameAsString();
+    std::string TypeString;
+    RewriteByRefString(TypeString, Name, (*I));
+    TypeString += " *";
+    Name = TypeString + Name;
+    S += Name + " = __cself->" + (*I)->getNameAsString() + "; // bound by ref\n";
+  }
+  // Next, emit a declaration for all "by copy" declarations.
+  for (SmallVectorImpl<ValueDecl *>::iterator I = BlockByCopyDecls.begin(),
+       E = BlockByCopyDecls.end(); I != E; ++I) {
+    S += "  ";
+    // Handle nested closure invocation. For example:
+    //
+    //   void (^myImportedClosure)(void);
+    //   myImportedClosure  = ^(void) { setGlobalInt(x + y); };
+    //
+    //   void (^anotherClosure)(void);
+    //   anotherClosure = ^(void) {
+    //     myImportedClosure(); // import and invoke the closure
+    //   };
+    //
+    if (isTopLevelBlockPointerType((*I)->getType())) {
+      RewriteBlockPointerTypeVariable(S, (*I));
+      S += " = (";
+      RewriteBlockPointerType(S, (*I)->getType());
+      S += ")";
+      S += "__cself->" + (*I)->getNameAsString() + "; // bound by copy\n";
+    }
+    else {
+      std::string Name = (*I)->getNameAsString();
+      QualType QT = (*I)->getType();
+      if (HasLocalVariableExternalStorage(*I))
+        QT = Context->getPointerType(QT);
+      QT.getAsStringInternal(Name, Context->getPrintingPolicy());
+      S += Name + " = __cself->" + 
+                              (*I)->getNameAsString() + "; // bound by copy\n";
+    }
+  }
+  std::string RewrittenStr = RewrittenBlockExprs[CE];
+  const char *cstr = RewrittenStr.c_str();
+  while (*cstr++ != '{') ;
+  S += cstr;
+  S += "\n";
+  return S;
+}
+
+std::string RewriteModernObjC::SynthesizeBlockHelperFuncs(BlockExpr *CE, int i,
+                                                   StringRef funcName,
+                                                   std::string Tag) {
+  std::string StructRef = "struct " + Tag;
+  std::string S = "static void __";
+
+  S += funcName;
+  S += "_block_copy_" + utostr(i);
+  S += "(" + StructRef;
+  S += "*dst, " + StructRef;
+  S += "*src) {";
+  for (llvm::SmallPtrSet<ValueDecl*,8>::iterator I = ImportedBlockDecls.begin(),
+      E = ImportedBlockDecls.end(); I != E; ++I) {
+    ValueDecl *VD = (*I);
+    S += "_Block_object_assign((void*)&dst->";
+    S += (*I)->getNameAsString();
+    S += ", (void*)src->";
+    S += (*I)->getNameAsString();
+    if (BlockByRefDeclsPtrSet.count((*I)))
+      S += ", " + utostr(BLOCK_FIELD_IS_BYREF) + "/*BLOCK_FIELD_IS_BYREF*/);";
+    else if (VD->getType()->isBlockPointerType())
+      S += ", " + utostr(BLOCK_FIELD_IS_BLOCK) + "/*BLOCK_FIELD_IS_BLOCK*/);";
+    else
+      S += ", " + utostr(BLOCK_FIELD_IS_OBJECT) + "/*BLOCK_FIELD_IS_OBJECT*/);";
+  }
+  S += "}\n";
+  
+  S += "\nstatic void __";
+  S += funcName;
+  S += "_block_dispose_" + utostr(i);
+  S += "(" + StructRef;
+  S += "*src) {";
+  for (llvm::SmallPtrSet<ValueDecl*,8>::iterator I = ImportedBlockDecls.begin(),
+      E = ImportedBlockDecls.end(); I != E; ++I) {
+    ValueDecl *VD = (*I);
+    S += "_Block_object_dispose((void*)src->";
+    S += (*I)->getNameAsString();
+    if (BlockByRefDeclsPtrSet.count((*I)))
+      S += ", " + utostr(BLOCK_FIELD_IS_BYREF) + "/*BLOCK_FIELD_IS_BYREF*/);";
+    else if (VD->getType()->isBlockPointerType())
+      S += ", " + utostr(BLOCK_FIELD_IS_BLOCK) + "/*BLOCK_FIELD_IS_BLOCK*/);";
+    else
+      S += ", " + utostr(BLOCK_FIELD_IS_OBJECT) + "/*BLOCK_FIELD_IS_OBJECT*/);";
+  }
+  S += "}\n";
+  return S;
+}
+
+std::string RewriteModernObjC::SynthesizeBlockImpl(BlockExpr *CE, std::string Tag, 
+                                             std::string Desc) {
+  std::string S = "\nstruct " + Tag;
+  std::string Constructor = "  " + Tag;
+
+  S += " {\n  struct __block_impl impl;\n";
+  S += "  struct " + Desc;
+  S += "* Desc;\n";
+
+  Constructor += "(void *fp, "; // Invoke function pointer.
+  Constructor += "struct " + Desc; // Descriptor pointer.
+  Constructor += " *desc";
+
+  if (BlockDeclRefs.size()) {
+    // Output all "by copy" declarations.
+    for (SmallVectorImpl<ValueDecl *>::iterator I = BlockByCopyDecls.begin(),
+         E = BlockByCopyDecls.end(); I != E; ++I) {
+      S += "  ";
+      std::string FieldName = (*I)->getNameAsString();
+      std::string ArgName = "_" + FieldName;
+      // Handle nested closure invocation. For example:
+      //
+      //   void (^myImportedBlock)(void);
+      //   myImportedBlock  = ^(void) { setGlobalInt(x + y); };
+      //
+      //   void (^anotherBlock)(void);
+      //   anotherBlock = ^(void) {
+      //     myImportedBlock(); // import and invoke the closure
+      //   };
+      //
+      if (isTopLevelBlockPointerType((*I)->getType())) {
+        S += "struct __block_impl *";
+        Constructor += ", void *" + ArgName;
+      } else {
+        QualType QT = (*I)->getType();
+        if (HasLocalVariableExternalStorage(*I))
+          QT = Context->getPointerType(QT);
+        QT.getAsStringInternal(FieldName, Context->getPrintingPolicy());
+        QT.getAsStringInternal(ArgName, Context->getPrintingPolicy());
+        Constructor += ", " + ArgName;
+      }
+      S += FieldName + ";\n";
+    }
+    // Output all "by ref" declarations.
+    for (SmallVectorImpl<ValueDecl *>::iterator I = BlockByRefDecls.begin(),
+         E = BlockByRefDecls.end(); I != E; ++I) {
+      S += "  ";
+      std::string FieldName = (*I)->getNameAsString();
+      std::string ArgName = "_" + FieldName;
+      {
+        std::string TypeString;
+        RewriteByRefString(TypeString, FieldName, (*I));
+        TypeString += " *";
+        FieldName = TypeString + FieldName;
+        ArgName = TypeString + ArgName;
+        Constructor += ", " + ArgName;
+      }
+      S += FieldName + "; // by ref\n";
+    }
+    // Finish writing the constructor.
+    Constructor += ", int flags=0)";
+    // Initialize all "by copy" arguments.
+    bool firsTime = true;
+    for (SmallVectorImpl<ValueDecl *>::iterator I = BlockByCopyDecls.begin(),
+         E = BlockByCopyDecls.end(); I != E; ++I) {
+      std::string Name = (*I)->getNameAsString();
+        if (firsTime) {
+          Constructor += " : ";
+          firsTime = false;
+        }
+        else
+          Constructor += ", ";
+        if (isTopLevelBlockPointerType((*I)->getType()))
+          Constructor += Name + "((struct __block_impl *)_" + Name + ")";
+        else
+          Constructor += Name + "(_" + Name + ")";
+    }
+    // Initialize all "by ref" arguments.
+    for (SmallVectorImpl<ValueDecl *>::iterator I = BlockByRefDecls.begin(),
+         E = BlockByRefDecls.end(); I != E; ++I) {
+      std::string Name = (*I)->getNameAsString();
+      if (firsTime) {
+        Constructor += " : ";
+        firsTime = false;
+      }
+      else
+        Constructor += ", ";
+      Constructor += Name + "(_" + Name + "->__forwarding)";
+    }
+    
+    Constructor += " {\n";
+    if (GlobalVarDecl)
+      Constructor += "    impl.isa = &_NSConcreteGlobalBlock;\n";
+    else
+      Constructor += "    impl.isa = &_NSConcreteStackBlock;\n";
+    Constructor += "    impl.Flags = flags;\n    impl.FuncPtr = fp;\n";
+
+    Constructor += "    Desc = desc;\n";
+  } else {
+    // Finish writing the constructor.
+    Constructor += ", int flags=0) {\n";
+    if (GlobalVarDecl)
+      Constructor += "    impl.isa = &_NSConcreteGlobalBlock;\n";
+    else
+      Constructor += "    impl.isa = &_NSConcreteStackBlock;\n";
+    Constructor += "    impl.Flags = flags;\n    impl.FuncPtr = fp;\n";
+    Constructor += "    Desc = desc;\n";
+  }
+  Constructor += "  ";
+  Constructor += "}\n";
+  S += Constructor;
+  S += "};\n";
+  return S;
+}
+
+std::string RewriteModernObjC::SynthesizeBlockDescriptor(std::string DescTag, 
+                                                   std::string ImplTag, int i,
+                                                   StringRef FunName,
+                                                   unsigned hasCopy) {
+  std::string S = "\nstatic struct " + DescTag;
+  
+  S += " {\n  size_t reserved;\n";
+  S += "  size_t Block_size;\n";
+  if (hasCopy) {
+    S += "  void (*copy)(struct ";
+    S += ImplTag; S += "*, struct ";
+    S += ImplTag; S += "*);\n";
+    
+    S += "  void (*dispose)(struct ";
+    S += ImplTag; S += "*);\n";
+  }
+  S += "} ";
+
+  S += DescTag + "_DATA = { 0, sizeof(struct ";
+  S += ImplTag + ")";
+  if (hasCopy) {
+    S += ", __" + FunName.str() + "_block_copy_" + utostr(i);
+    S += ", __" + FunName.str() + "_block_dispose_" + utostr(i);
+  }
+  S += "};\n";
+  return S;
+}
+
+void RewriteModernObjC::SynthesizeBlockLiterals(SourceLocation FunLocStart,
+                                          StringRef FunName) {
+  bool RewriteSC = (GlobalVarDecl &&
+                    !Blocks.empty() &&
+                    GlobalVarDecl->getStorageClass() == SC_Static &&
+                    GlobalVarDecl->getType().getCVRQualifiers());
+  if (RewriteSC) {
+    std::string SC(" void __");
+    SC += GlobalVarDecl->getNameAsString();
+    SC += "() {}";
+    InsertText(FunLocStart, SC);
+  }
+  
+  // Insert closures that were part of the function.
+  for (unsigned i = 0, count=0; i < Blocks.size(); i++) {
+    CollectBlockDeclRefInfo(Blocks[i]);
+    // Need to copy-in the inner copied-in variables not actually used in this
+    // block.
+    for (int j = 0; j < InnerDeclRefsCount[i]; j++) {
+      DeclRefExpr *Exp = InnerDeclRefs[count++];
+      ValueDecl *VD = Exp->getDecl();
+      BlockDeclRefs.push_back(Exp);
+      if (!VD->hasAttr<BlocksAttr>()) {
+        if (!BlockByCopyDeclsPtrSet.count(VD)) {
+          BlockByCopyDeclsPtrSet.insert(VD);
+          BlockByCopyDecls.push_back(VD);
+        }
+        continue;
+      }
+
+      if (!BlockByRefDeclsPtrSet.count(VD)) {
+        BlockByRefDeclsPtrSet.insert(VD);
+        BlockByRefDecls.push_back(VD);
+      }
+
+      // imported objects in the inner blocks not used in the outer
+      // blocks must be copied/disposed in the outer block as well.
+      if (VD->getType()->isObjCObjectPointerType() || 
+          VD->getType()->isBlockPointerType())
+        ImportedBlockDecls.insert(VD);
+    }
+
+    std::string ImplTag = "__" + FunName.str() + "_block_impl_" + utostr(i);
+    std::string DescTag = "__" + FunName.str() + "_block_desc_" + utostr(i);
+
+    std::string CI = SynthesizeBlockImpl(Blocks[i], ImplTag, DescTag);
+
+    InsertText(FunLocStart, CI);
+
+    std::string CF = SynthesizeBlockFunc(Blocks[i], i, FunName, ImplTag);
+
+    InsertText(FunLocStart, CF);
+
+    if (ImportedBlockDecls.size()) {
+      std::string HF = SynthesizeBlockHelperFuncs(Blocks[i], i, FunName, ImplTag);
+      InsertText(FunLocStart, HF);
+    }
+    std::string BD = SynthesizeBlockDescriptor(DescTag, ImplTag, i, FunName,
+                                               ImportedBlockDecls.size() > 0);
+    InsertText(FunLocStart, BD);
+
+    BlockDeclRefs.clear();
+    BlockByRefDecls.clear();
+    BlockByRefDeclsPtrSet.clear();
+    BlockByCopyDecls.clear();
+    BlockByCopyDeclsPtrSet.clear();
+    ImportedBlockDecls.clear();
+  }
+  if (RewriteSC) {
+    // Must insert any 'const/volatile/static here. Since it has been
+    // removed as result of rewriting of block literals.
+    std::string SC;
+    if (GlobalVarDecl->getStorageClass() == SC_Static)
+      SC = "static ";
+    if (GlobalVarDecl->getType().isConstQualified())
+      SC += "const ";
+    if (GlobalVarDecl->getType().isVolatileQualified())
+      SC += "volatile ";
+    if (GlobalVarDecl->getType().isRestrictQualified())
+      SC += "restrict ";
+    InsertText(FunLocStart, SC);
+  }
+  if (GlobalConstructionExp) {
+    // extra fancy dance for global literal expression.
+    
+    // Always the latest block expression on the block stack.
+    std::string Tag = "__";
+    Tag += FunName;
+    Tag += "_block_impl_";
+    Tag += utostr(Blocks.size()-1);
+    std::string globalBuf = "static ";
+    globalBuf += Tag; globalBuf += " ";
+    std::string SStr;
+  
+    llvm::raw_string_ostream constructorExprBuf(SStr);
+    GlobalConstructionExp->printPretty(constructorExprBuf, nullptr,
+                                       PrintingPolicy(LangOpts));
+    globalBuf += constructorExprBuf.str();
+    globalBuf += ";\n";
+    InsertText(FunLocStart, globalBuf);
+    GlobalConstructionExp = nullptr;
+  }
+
+  Blocks.clear();
+  InnerDeclRefsCount.clear();
+  InnerDeclRefs.clear();
+  RewrittenBlockExprs.clear();
+}
+
+void RewriteModernObjC::InsertBlockLiteralsWithinFunction(FunctionDecl *FD) {
+  SourceLocation FunLocStart = 
+    (!Blocks.empty()) ? getFunctionSourceLocation(*this, FD)
+                      : FD->getTypeSpecStartLoc();
+  StringRef FuncName = FD->getName();
+
+  SynthesizeBlockLiterals(FunLocStart, FuncName);
+}
+
+static void BuildUniqueMethodName(std::string &Name,
+                                  ObjCMethodDecl *MD) {
+  ObjCInterfaceDecl *IFace = MD->getClassInterface();
+  Name = IFace->getName();
+  Name += "__" + MD->getSelector().getAsString();
+  // Convert colons to underscores.
+  std::string::size_type loc = 0;
+  while ((loc = Name.find(":", loc)) != std::string::npos)
+    Name.replace(loc, 1, "_");
+}
+
+void RewriteModernObjC::InsertBlockLiteralsWithinMethod(ObjCMethodDecl *MD) {
+  //fprintf(stderr,"In InsertBlockLiteralsWitinMethod\n");
+  //SourceLocation FunLocStart = MD->getLocStart();
+  SourceLocation FunLocStart = MD->getLocStart();
+  std::string FuncName;
+  BuildUniqueMethodName(FuncName, MD);
+  SynthesizeBlockLiterals(FunLocStart, FuncName);
+}
+
+void RewriteModernObjC::GetBlockDeclRefExprs(Stmt *S) {
+  for (Stmt::child_range CI = S->children(); CI; ++CI)
+    if (*CI) {
+      if (BlockExpr *CBE = dyn_cast<BlockExpr>(*CI))
+        GetBlockDeclRefExprs(CBE->getBody());
+      else
+        GetBlockDeclRefExprs(*CI);
+    }
+  // Handle specific things.
+  if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(S)) {
+    if (DRE->refersToEnclosingLocal()) {
+      // FIXME: Handle enums.
+      if (!isa<FunctionDecl>(DRE->getDecl()))
+        BlockDeclRefs.push_back(DRE);
+      if (HasLocalVariableExternalStorage(DRE->getDecl()))
+        BlockDeclRefs.push_back(DRE);
+    }
+  }
+  
+  return;
+}
+
+void RewriteModernObjC::GetInnerBlockDeclRefExprs(Stmt *S,
+                SmallVectorImpl<DeclRefExpr *> &InnerBlockDeclRefs,
+                llvm::SmallPtrSet<const DeclContext *, 8> &InnerContexts) {
+  for (Stmt::child_range CI = S->children(); CI; ++CI)
+    if (*CI) {
+      if (BlockExpr *CBE = dyn_cast<BlockExpr>(*CI)) {
+        InnerContexts.insert(cast<DeclContext>(CBE->getBlockDecl()));
+        GetInnerBlockDeclRefExprs(CBE->getBody(),
+                                  InnerBlockDeclRefs,
+                                  InnerContexts);
+      }
+      else
+        GetInnerBlockDeclRefExprs(*CI,
+                                  InnerBlockDeclRefs,
+                                  InnerContexts);
+
+    }
+  // Handle specific things.
+  if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(S)) {
+    if (DRE->refersToEnclosingLocal()) {
+      if (!isa<FunctionDecl>(DRE->getDecl()) &&
+          !InnerContexts.count(DRE->getDecl()->getDeclContext()))
+        InnerBlockDeclRefs.push_back(DRE);
+      if (VarDecl *Var = dyn_cast<VarDecl>(DRE->getDecl()))
+        if (Var->isFunctionOrMethodVarDecl())
+          ImportedLocalExternalDecls.insert(Var);
+    }
+  }
+  
+  return;
+}
+
+/// convertObjCTypeToCStyleType - This routine converts such objc types
+/// as qualified objects, and blocks to their closest c/c++ types that
+/// it can. It returns true if input type was modified.
+bool RewriteModernObjC::convertObjCTypeToCStyleType(QualType &T) {
+  QualType oldT = T;
+  convertBlockPointerToFunctionPointer(T);
+  if (T->isFunctionPointerType()) {
+    QualType PointeeTy;
+    if (const PointerType* PT = T->getAs<PointerType>()) {
+      PointeeTy = PT->getPointeeType();
+      if (const FunctionType *FT = PointeeTy->getAs<FunctionType>()) {
+        T = convertFunctionTypeOfBlocks(FT);
+        T = Context->getPointerType(T);
+      }
+    }
+  }
+  
+  convertToUnqualifiedObjCType(T);
+  return T != oldT;
+}
+
+/// convertFunctionTypeOfBlocks - This routine converts a function type
+/// whose result type may be a block pointer or whose argument type(s)
+/// might be block pointers to an equivalent function type replacing
+/// all block pointers to function pointers.
+QualType RewriteModernObjC::convertFunctionTypeOfBlocks(const FunctionType *FT) {
+  const FunctionProtoType *FTP = dyn_cast<FunctionProtoType>(FT);
+  // FTP will be null for closures that don't take arguments.
+  // Generate a funky cast.
+  SmallVector<QualType, 8> ArgTypes;
+  QualType Res = FT->getReturnType();
+  bool modified = convertObjCTypeToCStyleType(Res);
+  
+  if (FTP) {
+    for (auto &I : FTP->param_types()) {
+      QualType t = I;
+      // Make sure we convert "t (^)(...)" to "t (*)(...)".
+      if (convertObjCTypeToCStyleType(t))
+        modified = true;
+      ArgTypes.push_back(t);
+    }
+  }
+  QualType FuncType;
+  if (modified)
+    FuncType = getSimpleFunctionType(Res, ArgTypes);
+  else FuncType = QualType(FT, 0);
+  return FuncType;
+}
+
+Stmt *RewriteModernObjC::SynthesizeBlockCall(CallExpr *Exp, const Expr *BlockExp) {
+  // Navigate to relevant type information.
+  const BlockPointerType *CPT = nullptr;
+
+  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BlockExp)) {
+    CPT = DRE->getType()->getAs<BlockPointerType>();
+  } else if (const MemberExpr *MExpr = dyn_cast<MemberExpr>(BlockExp)) {
+    CPT = MExpr->getType()->getAs<BlockPointerType>();
+  } 
+  else if (const ParenExpr *PRE = dyn_cast<ParenExpr>(BlockExp)) {
+    return SynthesizeBlockCall(Exp, PRE->getSubExpr());
+  }
+  else if (const ImplicitCastExpr *IEXPR = dyn_cast<ImplicitCastExpr>(BlockExp)) 
+    CPT = IEXPR->getType()->getAs<BlockPointerType>();
+  else if (const ConditionalOperator *CEXPR = 
+            dyn_cast<ConditionalOperator>(BlockExp)) {
+    Expr *LHSExp = CEXPR->getLHS();
+    Stmt *LHSStmt = SynthesizeBlockCall(Exp, LHSExp);
+    Expr *RHSExp = CEXPR->getRHS();
+    Stmt *RHSStmt = SynthesizeBlockCall(Exp, RHSExp);
+    Expr *CONDExp = CEXPR->getCond();
+    ConditionalOperator *CondExpr =
+      new (Context) ConditionalOperator(CONDExp,
+                                      SourceLocation(), cast<Expr>(LHSStmt),
+                                      SourceLocation(), cast<Expr>(RHSStmt),
+                                      Exp->getType(), VK_RValue, OK_Ordinary);
+    return CondExpr;
+  } else if (const ObjCIvarRefExpr *IRE = dyn_cast<ObjCIvarRefExpr>(BlockExp)) {
+    CPT = IRE->getType()->getAs<BlockPointerType>();
+  } else if (const PseudoObjectExpr *POE
+               = dyn_cast<PseudoObjectExpr>(BlockExp)) {
+    CPT = POE->getType()->castAs<BlockPointerType>();
+  } else {
+    assert(1 && "RewriteBlockClass: Bad type");
+  }
+  assert(CPT && "RewriteBlockClass: Bad type");
+  const FunctionType *FT = CPT->getPointeeType()->getAs<FunctionType>();
+  assert(FT && "RewriteBlockClass: Bad type");
+  const FunctionProtoType *FTP = dyn_cast<FunctionProtoType>(FT);
+  // FTP will be null for closures that don't take arguments.
+
+  RecordDecl *RD = RecordDecl::Create(*Context, TTK_Struct, TUDecl,
+                                      SourceLocation(), SourceLocation(),
+                                      &Context->Idents.get("__block_impl"));
+  QualType PtrBlock = Context->getPointerType(Context->getTagDeclType(RD));
+
+  // Generate a funky cast.
+  SmallVector<QualType, 8> ArgTypes;
+
+  // Push the block argument type.
+  ArgTypes.push_back(PtrBlock);
+  if (FTP) {
+    for (auto &I : FTP->param_types()) {
+      QualType t = I;
+      // Make sure we convert "t (^)(...)" to "t (*)(...)".
+      if (!convertBlockPointerToFunctionPointer(t))
+        convertToUnqualifiedObjCType(t);
+      ArgTypes.push_back(t);
+    }
+  }
+  // Now do the pointer to function cast.
+  QualType PtrToFuncCastType = getSimpleFunctionType(Exp->getType(), ArgTypes);
+
+  PtrToFuncCastType = Context->getPointerType(PtrToFuncCastType);
+
+  CastExpr *BlkCast = NoTypeInfoCStyleCastExpr(Context, PtrBlock,
+                                               CK_BitCast,
+                                               const_cast<Expr*>(BlockExp));
+  // Don't forget the parens to enforce the proper binding.
+  ParenExpr *PE = new (Context) ParenExpr(SourceLocation(), SourceLocation(),
+                                          BlkCast);
+  //PE->dump();
+
+  FieldDecl *FD = FieldDecl::Create(*Context, nullptr, SourceLocation(),
+                                    SourceLocation(),
+                                    &Context->Idents.get("FuncPtr"),
+                                    Context->VoidPtrTy, nullptr,
+                                    /*BitWidth=*/nullptr, /*Mutable=*/true,
+                                    ICIS_NoInit);
+  MemberExpr *ME = new (Context) MemberExpr(PE, true, FD, SourceLocation(),
+                                            FD->getType(), VK_LValue,
+                                            OK_Ordinary);
+
+  
+  CastExpr *FunkCast = NoTypeInfoCStyleCastExpr(Context, PtrToFuncCastType,
+                                                CK_BitCast, ME);
+  PE = new (Context) ParenExpr(SourceLocation(), SourceLocation(), FunkCast);
+
+  SmallVector<Expr*, 8> BlkExprs;
+  // Add the implicit argument.
+  BlkExprs.push_back(BlkCast);
+  // Add the user arguments.
+  for (CallExpr::arg_iterator I = Exp->arg_begin(),
+       E = Exp->arg_end(); I != E; ++I) {
+    BlkExprs.push_back(*I);
+  }
+  CallExpr *CE = new (Context) CallExpr(*Context, PE, BlkExprs,
+                                        Exp->getType(), VK_RValue,
+                                        SourceLocation());
+  return CE;
+}
+
+// We need to return the rewritten expression to handle cases where the
+// DeclRefExpr is embedded in another expression being rewritten.
+// For example:
+//
+// int main() {
+//    __block Foo *f;
+//    __block int i;
+//
+//    void (^myblock)() = ^() {
+//        [f test]; // f is a DeclRefExpr embedded in a message (which is being rewritten).
+//        i = 77;
+//    };
+//}
+Stmt *RewriteModernObjC::RewriteBlockDeclRefExpr(DeclRefExpr *DeclRefExp) {
+  // Rewrite the byref variable into BYREFVAR->__forwarding->BYREFVAR 
+  // for each DeclRefExp where BYREFVAR is name of the variable.
+  ValueDecl *VD = DeclRefExp->getDecl();
+  bool isArrow = DeclRefExp->refersToEnclosingLocal();
+
+  FieldDecl *FD = FieldDecl::Create(*Context, nullptr, SourceLocation(),
+                                    SourceLocation(),
+                                    &Context->Idents.get("__forwarding"), 
+                                    Context->VoidPtrTy, nullptr,
+                                    /*BitWidth=*/nullptr, /*Mutable=*/true,
+                                    ICIS_NoInit);
+  MemberExpr *ME = new (Context) MemberExpr(DeclRefExp, isArrow,
+                                            FD, SourceLocation(),
+                                            FD->getType(), VK_LValue,
+                                            OK_Ordinary);
+
+  StringRef Name = VD->getName();
+  FD = FieldDecl::Create(*Context, nullptr, SourceLocation(), SourceLocation(),
+                         &Context->Idents.get(Name), 
+                         Context->VoidPtrTy, nullptr,
+                         /*BitWidth=*/nullptr, /*Mutable=*/true,
+                         ICIS_NoInit);
+  ME = new (Context) MemberExpr(ME, true, FD, SourceLocation(),
+                                DeclRefExp->getType(), VK_LValue, OK_Ordinary);
+  
+  
+  
+  // Need parens to enforce precedence.
+  ParenExpr *PE = new (Context) ParenExpr(DeclRefExp->getExprLoc(), 
+                                          DeclRefExp->getExprLoc(), 
+                                          ME);
+  ReplaceStmt(DeclRefExp, PE);
+  return PE;
+}
+
+// Rewrites the imported local variable V with external storage 
+// (static, extern, etc.) as *V
+//
+Stmt *RewriteModernObjC::RewriteLocalVariableExternalStorage(DeclRefExpr *DRE) {
+  ValueDecl *VD = DRE->getDecl();
+  if (VarDecl *Var = dyn_cast<VarDecl>(VD))
+    if (!ImportedLocalExternalDecls.count(Var))
+      return DRE;
+  Expr *Exp = new (Context) UnaryOperator(DRE, UO_Deref, DRE->getType(),
+                                          VK_LValue, OK_Ordinary,
+                                          DRE->getLocation());
+  // Need parens to enforce precedence.
+  ParenExpr *PE = new (Context) ParenExpr(SourceLocation(), SourceLocation(), 
+                                          Exp);
+  ReplaceStmt(DRE, PE);
+  return PE;
+}
+
+void RewriteModernObjC::RewriteCastExpr(CStyleCastExpr *CE) {
+  SourceLocation LocStart = CE->getLParenLoc();
+  SourceLocation LocEnd = CE->getRParenLoc();
+
+  // Need to avoid trying to rewrite synthesized casts.
+  if (LocStart.isInvalid())
+    return;
+  // Need to avoid trying to rewrite casts contained in macros.
+  if (!Rewriter::isRewritable(LocStart) || !Rewriter::isRewritable(LocEnd))
+    return;
+
+  const char *startBuf = SM->getCharacterData(LocStart);
+  const char *endBuf = SM->getCharacterData(LocEnd);
+  QualType QT = CE->getType();
+  const Type* TypePtr = QT->getAs<Type>();
+  if (isa<TypeOfExprType>(TypePtr)) {
+    const TypeOfExprType *TypeOfExprTypePtr = cast<TypeOfExprType>(TypePtr);
+    QT = TypeOfExprTypePtr->getUnderlyingExpr()->getType();
+    std::string TypeAsString = "(";
+    RewriteBlockPointerType(TypeAsString, QT);
+    TypeAsString += ")";
+    ReplaceText(LocStart, endBuf-startBuf+1, TypeAsString);
+    return;
+  }
+  // advance the location to startArgList.
+  const char *argPtr = startBuf;
+
+  while (*argPtr++ && (argPtr < endBuf)) {
+    switch (*argPtr) {
+    case '^':
+      // Replace the '^' with '*'.
+      LocStart = LocStart.getLocWithOffset(argPtr-startBuf);
+      ReplaceText(LocStart, 1, "*");
+      break;
+    }
+  }
+  return;
+}
+
+void RewriteModernObjC::RewriteImplicitCastObjCExpr(CastExpr *IC) {
+  CastKind CastKind = IC->getCastKind();
+  if (CastKind != CK_BlockPointerToObjCPointerCast &&
+      CastKind != CK_AnyPointerToBlockPointerCast)
+    return;
+  
+  QualType QT = IC->getType();
+  (void)convertBlockPointerToFunctionPointer(QT);
+  std::string TypeString(QT.getAsString(Context->getPrintingPolicy()));
+  std::string Str = "(";
+  Str += TypeString;
+  Str += ")";
+  InsertText(IC->getSubExpr()->getLocStart(), &Str[0], Str.size());
+
+  return;
+}
+
+void RewriteModernObjC::RewriteBlockPointerFunctionArgs(FunctionDecl *FD) {
+  SourceLocation DeclLoc = FD->getLocation();
+  unsigned parenCount = 0;
+
+  // We have 1 or more arguments that have closure pointers.
+  const char *startBuf = SM->getCharacterData(DeclLoc);
+  const char *startArgList = strchr(startBuf, '(');
+
+  assert((*startArgList == '(') && "Rewriter fuzzy parser confused");
+
+  parenCount++;
+  // advance the location to startArgList.
+  DeclLoc = DeclLoc.getLocWithOffset(startArgList-startBuf);
+  assert((DeclLoc.isValid()) && "Invalid DeclLoc");
+
+  const char *argPtr = startArgList;
+
+  while (*argPtr++ && parenCount) {
+    switch (*argPtr) {
+    case '^':
+      // Replace the '^' with '*'.
+      DeclLoc = DeclLoc.getLocWithOffset(argPtr-startArgList);
+      ReplaceText(DeclLoc, 1, "*");
+      break;
+    case '(':
+      parenCount++;
+      break;
+    case ')':
+      parenCount--;
+      break;
+    }
+  }
+  return;
+}
+
+bool RewriteModernObjC::PointerTypeTakesAnyBlockArguments(QualType QT) {
+  const FunctionProtoType *FTP;
+  const PointerType *PT = QT->getAs<PointerType>();
+  if (PT) {
+    FTP = PT->getPointeeType()->getAs<FunctionProtoType>();
+  } else {
+    const BlockPointerType *BPT = QT->getAs<BlockPointerType>();
+    assert(BPT && "BlockPointerTypeTakeAnyBlockArguments(): not a block pointer type");
+    FTP = BPT->getPointeeType()->getAs<FunctionProtoType>();
+  }
+  if (FTP) {
+    for (const auto &I : FTP->param_types())
+      if (isTopLevelBlockPointerType(I))
+        return true;
+  }
+  return false;
+}
+
+bool RewriteModernObjC::PointerTypeTakesAnyObjCQualifiedType(QualType QT) {
+  const FunctionProtoType *FTP;
+  const PointerType *PT = QT->getAs<PointerType>();
+  if (PT) {
+    FTP = PT->getPointeeType()->getAs<FunctionProtoType>();
+  } else {
+    const BlockPointerType *BPT = QT->getAs<BlockPointerType>();
+    assert(BPT && "BlockPointerTypeTakeAnyBlockArguments(): not a block pointer type");
+    FTP = BPT->getPointeeType()->getAs<FunctionProtoType>();
+  }
+  if (FTP) {
+    for (const auto &I : FTP->param_types()) {
+      if (I->isObjCQualifiedIdType())
+        return true;
+      if (I->isObjCObjectPointerType() &&
+          I->getPointeeType()->isObjCQualifiedInterfaceType())
+        return true;
+    }
+        
+  }
+  return false;
+}
+
+void RewriteModernObjC::GetExtentOfArgList(const char *Name, const char *&LParen,
+                                     const char *&RParen) {
+  const char *argPtr = strchr(Name, '(');
+  assert((*argPtr == '(') && "Rewriter fuzzy parser confused");
+
+  LParen = argPtr; // output the start.
+  argPtr++; // skip past the left paren.
+  unsigned parenCount = 1;
+
+  while (*argPtr && parenCount) {
+    switch (*argPtr) {
+    case '(': parenCount++; break;
+    case ')': parenCount--; break;
+    default: break;
+    }
+    if (parenCount) argPtr++;
+  }
+  assert((*argPtr == ')') && "Rewriter fuzzy parser confused");
+  RParen = argPtr; // output the end
+}
+
+void RewriteModernObjC::RewriteBlockPointerDecl(NamedDecl *ND) {
+  if (FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
+    RewriteBlockPointerFunctionArgs(FD);
+    return;
+  }
+  // Handle Variables and Typedefs.
+  SourceLocation DeclLoc = ND->getLocation();
+  QualType DeclT;
+  if (VarDecl *VD = dyn_cast<VarDecl>(ND))
+    DeclT = VD->getType();
+  else if (TypedefNameDecl *TDD = dyn_cast<TypedefNameDecl>(ND))
+    DeclT = TDD->getUnderlyingType();
+  else if (FieldDecl *FD = dyn_cast<FieldDecl>(ND))
+    DeclT = FD->getType();
+  else
+    llvm_unreachable("RewriteBlockPointerDecl(): Decl type not yet handled");
+
+  const char *startBuf = SM->getCharacterData(DeclLoc);
+  const char *endBuf = startBuf;
+  // scan backward (from the decl location) for the end of the previous decl.
+  while (*startBuf != '^' && *startBuf != ';' && startBuf != MainFileStart)
+    startBuf--;
+  SourceLocation Start = DeclLoc.getLocWithOffset(startBuf-endBuf);
+  std::string buf;
+  unsigned OrigLength=0;
+  // *startBuf != '^' if we are dealing with a pointer to function that
+  // may take block argument types (which will be handled below).
+  if (*startBuf == '^') {
+    // Replace the '^' with '*', computing a negative offset.
+    buf = '*';
+    startBuf++;
+    OrigLength++;
+  }
+  while (*startBuf != ')') {
+    buf += *startBuf;
+    startBuf++;
+    OrigLength++;
+  }
+  buf += ')';
+  OrigLength++;
+  
+  if (PointerTypeTakesAnyBlockArguments(DeclT) ||
+      PointerTypeTakesAnyObjCQualifiedType(DeclT)) {
+    // Replace the '^' with '*' for arguments.
+    // Replace id<P> with id/*<>*/
+    DeclLoc = ND->getLocation();
+    startBuf = SM->getCharacterData(DeclLoc);
+    const char *argListBegin, *argListEnd;
+    GetExtentOfArgList(startBuf, argListBegin, argListEnd);
+    while (argListBegin < argListEnd) {
+      if (*argListBegin == '^')
+        buf += '*';
+      else if (*argListBegin ==  '<') {
+        buf += "/*"; 
+        buf += *argListBegin++;
+        OrigLength++;
+        while (*argListBegin != '>') {
+          buf += *argListBegin++;
+          OrigLength++;
+        }
+        buf += *argListBegin;
+        buf += "*/";
+      }
+      else
+        buf += *argListBegin;
+      argListBegin++;
+      OrigLength++;
+    }
+    buf += ')';
+    OrigLength++;
+  }
+  ReplaceText(Start, OrigLength, buf);
+  
+  return;
+}
+
+
+/// SynthesizeByrefCopyDestroyHelper - This routine synthesizes:
+/// void __Block_byref_id_object_copy(struct Block_byref_id_object *dst,
+///                    struct Block_byref_id_object *src) {
+///  _Block_object_assign (&_dest->object, _src->object, 
+///                        BLOCK_BYREF_CALLER | BLOCK_FIELD_IS_OBJECT
+///                        [|BLOCK_FIELD_IS_WEAK]) // object
+///  _Block_object_assign(&_dest->object, _src->object, 
+///                       BLOCK_BYREF_CALLER | BLOCK_FIELD_IS_BLOCK
+///                       [|BLOCK_FIELD_IS_WEAK]) // block
+/// }
+/// And:
+/// void __Block_byref_id_object_dispose(struct Block_byref_id_object *_src) {
+///  _Block_object_dispose(_src->object, 
+///                        BLOCK_BYREF_CALLER | BLOCK_FIELD_IS_OBJECT
+///                        [|BLOCK_FIELD_IS_WEAK]) // object
+///  _Block_object_dispose(_src->object, 
+///                         BLOCK_BYREF_CALLER | BLOCK_FIELD_IS_BLOCK
+///                         [|BLOCK_FIELD_IS_WEAK]) // block
+/// }
+
+std::string RewriteModernObjC::SynthesizeByrefCopyDestroyHelper(VarDecl *VD,
+                                                          int flag) {
+  std::string S;
+  if (CopyDestroyCache.count(flag))
+    return S;
+  CopyDestroyCache.insert(flag);
+  S = "static void __Block_byref_id_object_copy_";
+  S += utostr(flag);
+  S += "(void *dst, void *src) {\n";
+  
+  // offset into the object pointer is computed as:
+  // void * + void* + int + int + void* + void *
+  unsigned IntSize = 
+  static_cast<unsigned>(Context->getTypeSize(Context->IntTy));
+  unsigned VoidPtrSize = 
+  static_cast<unsigned>(Context->getTypeSize(Context->VoidPtrTy));
+  
+  unsigned offset = (VoidPtrSize*4 + IntSize + IntSize)/Context->getCharWidth();
+  S += " _Block_object_assign((char*)dst + ";
+  S += utostr(offset);
+  S += ", *(void * *) ((char*)src + ";
+  S += utostr(offset);
+  S += "), ";
+  S += utostr(flag);
+  S += ");\n}\n";
+  
+  S += "static void __Block_byref_id_object_dispose_";
+  S += utostr(flag);
+  S += "(void *src) {\n";
+  S += " _Block_object_dispose(*(void * *) ((char*)src + ";
+  S += utostr(offset);
+  S += "), ";
+  S += utostr(flag);
+  S += ");\n}\n";
+  return S;
+}
+
+/// RewriteByRefVar - For each __block typex ND variable this routine transforms
+/// the declaration into:
+/// struct __Block_byref_ND {
+/// void *__isa;                  // NULL for everything except __weak pointers
+/// struct __Block_byref_ND *__forwarding;
+/// int32_t __flags;
+/// int32_t __size;
+/// void *__Block_byref_id_object_copy; // If variable is __block ObjC object
+/// void *__Block_byref_id_object_dispose; // If variable is __block ObjC object
+/// typex ND;
+/// };
+///
+/// It then replaces declaration of ND variable with:
+/// struct __Block_byref_ND ND = {__isa=0B, __forwarding=&ND, __flags=some_flag, 
+///                               __size=sizeof(struct __Block_byref_ND), 
+///                               ND=initializer-if-any};
+///
+///
+void RewriteModernObjC::RewriteByRefVar(VarDecl *ND, bool firstDecl,
+                                        bool lastDecl) {
+  int flag = 0;
+  int isa = 0;
+  SourceLocation DeclLoc = ND->getTypeSpecStartLoc();
+  if (DeclLoc.isInvalid())
+    // If type location is missing, it is because of missing type (a warning).
+    // Use variable's location which is good for this case.
+    DeclLoc = ND->getLocation();
+  const char *startBuf = SM->getCharacterData(DeclLoc);
+  SourceLocation X = ND->getLocEnd();
+  X = SM->getExpansionLoc(X);
+  const char *endBuf = SM->getCharacterData(X);
+  std::string Name(ND->getNameAsString());
+  std::string ByrefType;
+  RewriteByRefString(ByrefType, Name, ND, true);
+  ByrefType += " {\n";
+  ByrefType += "  void *__isa;\n";
+  RewriteByRefString(ByrefType, Name, ND);
+  ByrefType += " *__forwarding;\n";
+  ByrefType += " int __flags;\n";
+  ByrefType += " int __size;\n";
+  // Add void *__Block_byref_id_object_copy; 
+  // void *__Block_byref_id_object_dispose; if needed.
+  QualType Ty = ND->getType();
+  bool HasCopyAndDispose = Context->BlockRequiresCopying(Ty, ND);
+  if (HasCopyAndDispose) {
+    ByrefType += " void (*__Block_byref_id_object_copy)(void*, void*);\n";
+    ByrefType += " void (*__Block_byref_id_object_dispose)(void*);\n";
+  }
+
+  QualType T = Ty;
+  (void)convertBlockPointerToFunctionPointer(T);
+  T.getAsStringInternal(Name, Context->getPrintingPolicy());
+    
+  ByrefType += " " + Name + ";\n";
+  ByrefType += "};\n";
+  // Insert this type in global scope. It is needed by helper function.
+  SourceLocation FunLocStart;
+  if (CurFunctionDef)
+     FunLocStart = getFunctionSourceLocation(*this, CurFunctionDef);
+  else {
+    assert(CurMethodDef && "RewriteByRefVar - CurMethodDef is null");
+    FunLocStart = CurMethodDef->getLocStart();
+  }
+  InsertText(FunLocStart, ByrefType);
+  
+  if (Ty.isObjCGCWeak()) {
+    flag |= BLOCK_FIELD_IS_WEAK;
+    isa = 1;
+  }
+  if (HasCopyAndDispose) {
+    flag = BLOCK_BYREF_CALLER;
+    QualType Ty = ND->getType();
+    // FIXME. Handle __weak variable (BLOCK_FIELD_IS_WEAK) as well.
+    if (Ty->isBlockPointerType())
+      flag |= BLOCK_FIELD_IS_BLOCK;
+    else
+      flag |= BLOCK_FIELD_IS_OBJECT;
+    std::string HF = SynthesizeByrefCopyDestroyHelper(ND, flag);
+    if (!HF.empty())
+      Preamble += HF;
+  }
+  
+  // struct __Block_byref_ND ND = 
+  // {0, &ND, some_flag, __size=sizeof(struct __Block_byref_ND), 
+  //  initializer-if-any};
+  bool hasInit = (ND->getInit() != nullptr);
+  // FIXME. rewriter does not support __block c++ objects which
+  // require construction.
+  if (hasInit)
+    if (CXXConstructExpr *CExp = dyn_cast<CXXConstructExpr>(ND->getInit())) {
+      CXXConstructorDecl *CXXDecl = CExp->getConstructor();
+      if (CXXDecl && CXXDecl->isDefaultConstructor())
+        hasInit = false;
+    }
+  
+  unsigned flags = 0;
+  if (HasCopyAndDispose)
+    flags |= BLOCK_HAS_COPY_DISPOSE;
+  Name = ND->getNameAsString();
+  ByrefType.clear();
+  RewriteByRefString(ByrefType, Name, ND);
+  std::string ForwardingCastType("(");
+  ForwardingCastType += ByrefType + " *)";
+  ByrefType += " " + Name + " = {(void*)";
+  ByrefType += utostr(isa);
+  ByrefType += "," +  ForwardingCastType + "&" + Name + ", ";
+  ByrefType += utostr(flags);
+  ByrefType += ", ";
+  ByrefType += "sizeof(";
+  RewriteByRefString(ByrefType, Name, ND);
+  ByrefType += ")";
+  if (HasCopyAndDispose) {
+    ByrefType += ", __Block_byref_id_object_copy_";
+    ByrefType += utostr(flag);
+    ByrefType += ", __Block_byref_id_object_dispose_";
+    ByrefType += utostr(flag);
+  }
+  
+  if (!firstDecl) {
+    // In multiple __block declarations, and for all but 1st declaration,
+    // find location of the separating comma. This would be start location
+    // where new text is to be inserted.
+    DeclLoc = ND->getLocation();
+    const char *startDeclBuf = SM->getCharacterData(DeclLoc);
+    const char *commaBuf = startDeclBuf;
+    while (*commaBuf != ',')
+      commaBuf--;
+    assert((*commaBuf == ',') && "RewriteByRefVar: can't find ','");
+    DeclLoc = DeclLoc.getLocWithOffset(commaBuf - startDeclBuf);
+    startBuf = commaBuf;
+  }
+  
+  if (!hasInit) {
+    ByrefType += "};\n";
+    unsigned nameSize = Name.size();
+    // for block or function pointer declaration. Name is aleady
+    // part of the declaration.
+    if (Ty->isBlockPointerType() || Ty->isFunctionPointerType())
+      nameSize = 1;
+    ReplaceText(DeclLoc, endBuf-startBuf+nameSize, ByrefType);
+  }
+  else {
+    ByrefType += ", ";
+    SourceLocation startLoc;
+    Expr *E = ND->getInit();
+    if (const CStyleCastExpr *ECE = dyn_cast<CStyleCastExpr>(E))
+      startLoc = ECE->getLParenLoc();
+    else
+      startLoc = E->getLocStart();
+    startLoc = SM->getExpansionLoc(startLoc);
+    endBuf = SM->getCharacterData(startLoc);
+    ReplaceText(DeclLoc, endBuf-startBuf, ByrefType);
+
+    const char separator = lastDecl ? ';' : ',';
+    const char *startInitializerBuf = SM->getCharacterData(startLoc);
+    const char *separatorBuf = strchr(startInitializerBuf, separator);
+    assert((*separatorBuf == separator) && 
+           "RewriteByRefVar: can't find ';' or ','");
+    SourceLocation separatorLoc =
+      startLoc.getLocWithOffset(separatorBuf-startInitializerBuf);
+    
+    InsertText(separatorLoc, lastDecl ? "}" : "};\n");
+  }
+  return;
+}
+
+void RewriteModernObjC::CollectBlockDeclRefInfo(BlockExpr *Exp) {
+  // Add initializers for any closure decl refs.
+  GetBlockDeclRefExprs(Exp->getBody());
+  if (BlockDeclRefs.size()) {
+    // Unique all "by copy" declarations.
+    for (unsigned i = 0; i < BlockDeclRefs.size(); i++)
+      if (!BlockDeclRefs[i]->getDecl()->hasAttr<BlocksAttr>()) {
+        if (!BlockByCopyDeclsPtrSet.count(BlockDeclRefs[i]->getDecl())) {
+          BlockByCopyDeclsPtrSet.insert(BlockDeclRefs[i]->getDecl());
+          BlockByCopyDecls.push_back(BlockDeclRefs[i]->getDecl());
+        }
+      }
+    // Unique all "by ref" declarations.
+    for (unsigned i = 0; i < BlockDeclRefs.size(); i++)
+      if (BlockDeclRefs[i]->getDecl()->hasAttr<BlocksAttr>()) {
+        if (!BlockByRefDeclsPtrSet.count(BlockDeclRefs[i]->getDecl())) {
+          BlockByRefDeclsPtrSet.insert(BlockDeclRefs[i]->getDecl());
+          BlockByRefDecls.push_back(BlockDeclRefs[i]->getDecl());
+        }
+      }
+    // Find any imported blocks...they will need special attention.
+    for (unsigned i = 0; i < BlockDeclRefs.size(); i++)
+      if (BlockDeclRefs[i]->getDecl()->hasAttr<BlocksAttr>() ||
+          BlockDeclRefs[i]->getType()->isObjCObjectPointerType() || 
+          BlockDeclRefs[i]->getType()->isBlockPointerType())
+        ImportedBlockDecls.insert(BlockDeclRefs[i]->getDecl());
+  }
+}
+
+FunctionDecl *RewriteModernObjC::SynthBlockInitFunctionDecl(StringRef name) {
+  IdentifierInfo *ID = &Context->Idents.get(name);
+  QualType FType = Context->getFunctionNoProtoType(Context->VoidPtrTy);
+  return FunctionDecl::Create(*Context, TUDecl, SourceLocation(),
+                              SourceLocation(), ID, FType, nullptr, SC_Extern,
+                              false, false);
+}
+
+Stmt *RewriteModernObjC::SynthBlockInitExpr(BlockExpr *Exp,
+                     const SmallVectorImpl<DeclRefExpr *> &InnerBlockDeclRefs) {
+  
+  const BlockDecl *block = Exp->getBlockDecl();
+  
+  Blocks.push_back(Exp);
+
+  CollectBlockDeclRefInfo(Exp);
+  
+  // Add inner imported variables now used in current block.
+ int countOfInnerDecls = 0;
+  if (!InnerBlockDeclRefs.empty()) {
+    for (unsigned i = 0; i < InnerBlockDeclRefs.size(); i++) {
+      DeclRefExpr *Exp = InnerBlockDeclRefs[i];
+      ValueDecl *VD = Exp->getDecl();
+      if (!VD->hasAttr<BlocksAttr>() && !BlockByCopyDeclsPtrSet.count(VD)) {
+      // We need to save the copied-in variables in nested
+      // blocks because it is needed at the end for some of the API generations.
+      // See SynthesizeBlockLiterals routine.
+        InnerDeclRefs.push_back(Exp); countOfInnerDecls++;
+        BlockDeclRefs.push_back(Exp);
+        BlockByCopyDeclsPtrSet.insert(VD);
+        BlockByCopyDecls.push_back(VD);
+      }
+      if (VD->hasAttr<BlocksAttr>() && !BlockByRefDeclsPtrSet.count(VD)) {
+        InnerDeclRefs.push_back(Exp); countOfInnerDecls++;
+        BlockDeclRefs.push_back(Exp);
+        BlockByRefDeclsPtrSet.insert(VD);
+        BlockByRefDecls.push_back(VD);
+      }
+    }
+    // Find any imported blocks...they will need special attention.
+    for (unsigned i = 0; i < InnerBlockDeclRefs.size(); i++)
+      if (InnerBlockDeclRefs[i]->getDecl()->hasAttr<BlocksAttr>() ||
+          InnerBlockDeclRefs[i]->getType()->isObjCObjectPointerType() || 
+          InnerBlockDeclRefs[i]->getType()->isBlockPointerType())
+        ImportedBlockDecls.insert(InnerBlockDeclRefs[i]->getDecl());
+  }
+  InnerDeclRefsCount.push_back(countOfInnerDecls);
+  
+  std::string FuncName;
+
+  if (CurFunctionDef)
+    FuncName = CurFunctionDef->getNameAsString();
+  else if (CurMethodDef)
+    BuildUniqueMethodName(FuncName, CurMethodDef);
+  else if (GlobalVarDecl)
+    FuncName = std::string(GlobalVarDecl->getNameAsString());
+
+  bool GlobalBlockExpr = 
+    block->getDeclContext()->getRedeclContext()->isFileContext();
+  
+  if (GlobalBlockExpr && !GlobalVarDecl) {
+    Diags.Report(block->getLocation(), GlobalBlockRewriteFailedDiag);
+    GlobalBlockExpr = false;
+  }
+  
+  std::string BlockNumber = utostr(Blocks.size()-1);
+
+  std::string Func = "__" + FuncName + "_block_func_" + BlockNumber;
+
+  // Get a pointer to the function type so we can cast appropriately.
+  QualType BFT = convertFunctionTypeOfBlocks(Exp->getFunctionType());
+  QualType FType = Context->getPointerType(BFT);
+
+  FunctionDecl *FD;
+  Expr *NewRep;
+
+  // Simulate a constructor call...
+  std::string Tag;
+  
+  if (GlobalBlockExpr)
+    Tag = "__global_";
+  else
+    Tag = "__";
+  Tag += FuncName + "_block_impl_" + BlockNumber;
+  
+  FD = SynthBlockInitFunctionDecl(Tag);
+  DeclRefExpr *DRE = new (Context) DeclRefExpr(FD, false, FType, VK_RValue,
+                                               SourceLocation());
+
+  SmallVector<Expr*, 4> InitExprs;
+
+  // Initialize the block function.
+  FD = SynthBlockInitFunctionDecl(Func);
+  DeclRefExpr *Arg = new (Context) DeclRefExpr(FD, false, FD->getType(),
+                                               VK_LValue, SourceLocation());
+  CastExpr *castExpr = NoTypeInfoCStyleCastExpr(Context, Context->VoidPtrTy,
+                                                CK_BitCast, Arg);
+  InitExprs.push_back(castExpr);
+
+  // Initialize the block descriptor.
+  std::string DescData = "__" + FuncName + "_block_desc_" + BlockNumber + "_DATA";
+
+  VarDecl *NewVD = VarDecl::Create(*Context, TUDecl,
+                                   SourceLocation(), SourceLocation(),
+                                   &Context->Idents.get(DescData.c_str()),
+                                   Context->VoidPtrTy, nullptr,
+                                   SC_Static);
+  UnaryOperator *DescRefExpr =
+    new (Context) UnaryOperator(new (Context) DeclRefExpr(NewVD, false,
+                                                          Context->VoidPtrTy,
+                                                          VK_LValue,
+                                                          SourceLocation()), 
+                                UO_AddrOf,
+                                Context->getPointerType(Context->VoidPtrTy), 
+                                VK_RValue, OK_Ordinary,
+                                SourceLocation());
+  InitExprs.push_back(DescRefExpr); 
+  
+  // Add initializers for any closure decl refs.
+  if (BlockDeclRefs.size()) {
+    Expr *Exp;
+    // Output all "by copy" declarations.
+    for (SmallVectorImpl<ValueDecl *>::iterator I = BlockByCopyDecls.begin(),
+         E = BlockByCopyDecls.end(); I != E; ++I) {
+      if (isObjCType((*I)->getType())) {
+        // FIXME: Conform to ABI ([[obj retain] autorelease]).
+        FD = SynthBlockInitFunctionDecl((*I)->getName());
+        Exp = new (Context) DeclRefExpr(FD, false, FD->getType(),
+                                        VK_LValue, SourceLocation());
+        if (HasLocalVariableExternalStorage(*I)) {
+          QualType QT = (*I)->getType();
+          QT = Context->getPointerType(QT);
+          Exp = new (Context) UnaryOperator(Exp, UO_AddrOf, QT, VK_RValue,
+                                            OK_Ordinary, SourceLocation());
+        }
+      } else if (isTopLevelBlockPointerType((*I)->getType())) {
+        FD = SynthBlockInitFunctionDecl((*I)->getName());
+        Arg = new (Context) DeclRefExpr(FD, false, FD->getType(),
+                                        VK_LValue, SourceLocation());
+        Exp = NoTypeInfoCStyleCastExpr(Context, Context->VoidPtrTy,
+                                       CK_BitCast, Arg);
+      } else {
+        FD = SynthBlockInitFunctionDecl((*I)->getName());
+        Exp = new (Context) DeclRefExpr(FD, false, FD->getType(),
+                                        VK_LValue, SourceLocation());
+        if (HasLocalVariableExternalStorage(*I)) {
+          QualType QT = (*I)->getType();
+          QT = Context->getPointerType(QT);
+          Exp = new (Context) UnaryOperator(Exp, UO_AddrOf, QT, VK_RValue,
+                                            OK_Ordinary, SourceLocation());
+        }
+        
+      }
+      InitExprs.push_back(Exp);
+    }
+    // Output all "by ref" declarations.
+    for (SmallVectorImpl<ValueDecl *>::iterator I = BlockByRefDecls.begin(),
+         E = BlockByRefDecls.end(); I != E; ++I) {
+      ValueDecl *ND = (*I);
+      std::string Name(ND->getNameAsString());
+      std::string RecName;
+      RewriteByRefString(RecName, Name, ND, true);
+      IdentifierInfo *II = &Context->Idents.get(RecName.c_str() 
+                                                + sizeof("struct"));
+      RecordDecl *RD = RecordDecl::Create(*Context, TTK_Struct, TUDecl,
+                                          SourceLocation(), SourceLocation(),
+                                          II);
+      assert(RD && "SynthBlockInitExpr(): Can't find RecordDecl");
+      QualType castT = Context->getPointerType(Context->getTagDeclType(RD));
+      
+      FD = SynthBlockInitFunctionDecl((*I)->getName());
+      Exp = new (Context) DeclRefExpr(FD, false, FD->getType(), VK_LValue,
+                                      SourceLocation());
+      bool isNestedCapturedVar = false;
+      if (block)
+        for (const auto &CI : block->captures()) {
+          const VarDecl *variable = CI.getVariable();
+          if (variable == ND && CI.isNested()) {
+            assert (CI.isByRef() && 
+                    "SynthBlockInitExpr - captured block variable is not byref");
+            isNestedCapturedVar = true;
+            break;
+          }
+        }
+      // captured nested byref variable has its address passed. Do not take
+      // its address again.
+      if (!isNestedCapturedVar)
+          Exp = new (Context) UnaryOperator(Exp, UO_AddrOf,
+                                     Context->getPointerType(Exp->getType()),
+                                     VK_RValue, OK_Ordinary, SourceLocation());
+      Exp = NoTypeInfoCStyleCastExpr(Context, castT, CK_BitCast, Exp);
+      InitExprs.push_back(Exp);
+    }
+  }
+  if (ImportedBlockDecls.size()) {
+    // generate BLOCK_HAS_COPY_DISPOSE(have helper funcs) | BLOCK_HAS_DESCRIPTOR
+    int flag = (BLOCK_HAS_COPY_DISPOSE | BLOCK_HAS_DESCRIPTOR);
+    unsigned IntSize = 
+      static_cast<unsigned>(Context->getTypeSize(Context->IntTy));
+    Expr *FlagExp = IntegerLiteral::Create(*Context, llvm::APInt(IntSize, flag), 
+                                           Context->IntTy, SourceLocation());
+    InitExprs.push_back(FlagExp);
+  }
+  NewRep = new (Context) CallExpr(*Context, DRE, InitExprs,
+                                  FType, VK_LValue, SourceLocation());
+  
+  if (GlobalBlockExpr) {
+    assert (!GlobalConstructionExp &&
+            "SynthBlockInitExpr - GlobalConstructionExp must be null");
+    GlobalConstructionExp = NewRep;
+    NewRep = DRE;
+  }
+  
+  NewRep = new (Context) UnaryOperator(NewRep, UO_AddrOf,
+                             Context->getPointerType(NewRep->getType()),
+                             VK_RValue, OK_Ordinary, SourceLocation());
+  NewRep = NoTypeInfoCStyleCastExpr(Context, FType, CK_BitCast,
+                                    NewRep);
+  BlockDeclRefs.clear();
+  BlockByRefDecls.clear();
+  BlockByRefDeclsPtrSet.clear();
+  BlockByCopyDecls.clear();
+  BlockByCopyDeclsPtrSet.clear();
+  ImportedBlockDecls.clear();
+  return NewRep;
+}
+
+bool RewriteModernObjC::IsDeclStmtInForeachHeader(DeclStmt *DS) {
+  if (const ObjCForCollectionStmt * CS = 
+      dyn_cast<ObjCForCollectionStmt>(Stmts.back()))
+        return CS->getElement() == DS;
+  return false;
+}
+
+//===----------------------------------------------------------------------===//
+// Function Body / Expression rewriting
+//===----------------------------------------------------------------------===//
+
+Stmt *RewriteModernObjC::RewriteFunctionBodyOrGlobalInitializer(Stmt *S) {
+  if (isa<SwitchStmt>(S) || isa<WhileStmt>(S) ||
+      isa<DoStmt>(S) || isa<ForStmt>(S))
+    Stmts.push_back(S);
+  else if (isa<ObjCForCollectionStmt>(S)) {
+    Stmts.push_back(S);
+    ObjCBcLabelNo.push_back(++BcLabelCount);
+  }
+
+  // Pseudo-object operations and ivar references need special
+  // treatment because we're going to recursively rewrite them.
+  if (PseudoObjectExpr *PseudoOp = dyn_cast<PseudoObjectExpr>(S)) {
+    if (isa<BinaryOperator>(PseudoOp->getSyntacticForm())) {
+      return RewritePropertyOrImplicitSetter(PseudoOp);
+    } else {
+      return RewritePropertyOrImplicitGetter(PseudoOp);
+    }
+  } else if (ObjCIvarRefExpr *IvarRefExpr = dyn_cast<ObjCIvarRefExpr>(S)) {
+    return RewriteObjCIvarRefExpr(IvarRefExpr);
+  }
+  else if (isa<OpaqueValueExpr>(S))
+    S = cast<OpaqueValueExpr>(S)->getSourceExpr();
+
+  SourceRange OrigStmtRange = S->getSourceRange();
+
+  // Perform a bottom up rewrite of all children.
+  for (Stmt::child_range CI = S->children(); CI; ++CI)
+    if (*CI) {
+      Stmt *childStmt = (*CI);
+      Stmt *newStmt = RewriteFunctionBodyOrGlobalInitializer(childStmt);
+      if (newStmt) {
+        *CI = newStmt;
+      }
+    }
+
+  if (BlockExpr *BE = dyn_cast<BlockExpr>(S)) {
+    SmallVector<DeclRefExpr *, 8> InnerBlockDeclRefs;
+    llvm::SmallPtrSet<const DeclContext *, 8> InnerContexts;
+    InnerContexts.insert(BE->getBlockDecl());
+    ImportedLocalExternalDecls.clear();
+    GetInnerBlockDeclRefExprs(BE->getBody(),
+                              InnerBlockDeclRefs, InnerContexts);
+    // Rewrite the block body in place.
+    Stmt *SaveCurrentBody = CurrentBody;
+    CurrentBody = BE->getBody();
+    PropParentMap = nullptr;
+    // block literal on rhs of a property-dot-sytax assignment
+    // must be replaced by its synthesize ast so getRewrittenText
+    // works as expected. In this case, what actually ends up on RHS
+    // is the blockTranscribed which is the helper function for the
+    // block literal; as in: self.c = ^() {[ace ARR];};
+    bool saveDisableReplaceStmt = DisableReplaceStmt;
+    DisableReplaceStmt = false;
+    RewriteFunctionBodyOrGlobalInitializer(BE->getBody());
+    DisableReplaceStmt = saveDisableReplaceStmt;
+    CurrentBody = SaveCurrentBody;
+    PropParentMap = nullptr;
+    ImportedLocalExternalDecls.clear();
+    // Now we snarf the rewritten text and stash it away for later use.
+    std::string Str = Rewrite.getRewrittenText(BE->getSourceRange());
+    RewrittenBlockExprs[BE] = Str;
+
+    Stmt *blockTranscribed = SynthBlockInitExpr(BE, InnerBlockDeclRefs);
+                            
+    //blockTranscribed->dump();
+    ReplaceStmt(S, blockTranscribed);
+    return blockTranscribed;
+  }
+  // Handle specific things.
+  if (ObjCEncodeExpr *AtEncode = dyn_cast<ObjCEncodeExpr>(S))
+    return RewriteAtEncode(AtEncode);
+
+  if (ObjCSelectorExpr *AtSelector = dyn_cast<ObjCSelectorExpr>(S))
+    return RewriteAtSelector(AtSelector);
+
+  if (ObjCStringLiteral *AtString = dyn_cast<ObjCStringLiteral>(S))
+    return RewriteObjCStringLiteral(AtString);
+  
+  if (ObjCBoolLiteralExpr *BoolLitExpr = dyn_cast<ObjCBoolLiteralExpr>(S))
+    return RewriteObjCBoolLiteralExpr(BoolLitExpr);
+  
+  if (ObjCBoxedExpr *BoxedExpr = dyn_cast<ObjCBoxedExpr>(S))
+    return RewriteObjCBoxedExpr(BoxedExpr);
+  
+  if (ObjCArrayLiteral *ArrayLitExpr = dyn_cast<ObjCArrayLiteral>(S))
+    return RewriteObjCArrayLiteralExpr(ArrayLitExpr);
+  
+  if (ObjCDictionaryLiteral *DictionaryLitExpr = 
+        dyn_cast<ObjCDictionaryLiteral>(S))
+    return RewriteObjCDictionaryLiteralExpr(DictionaryLitExpr);
+
+  if (ObjCMessageExpr *MessExpr = dyn_cast<ObjCMessageExpr>(S)) {
+#if 0
+    // Before we rewrite it, put the original message expression in a comment.
+    SourceLocation startLoc = MessExpr->getLocStart();
+    SourceLocation endLoc = MessExpr->getLocEnd();
+
+    const char *startBuf = SM->getCharacterData(startLoc);
+    const char *endBuf = SM->getCharacterData(endLoc);
+
+    std::string messString;
+    messString += "// ";
+    messString.append(startBuf, endBuf-startBuf+1);
+    messString += "\n";
+
+    // FIXME: Missing definition of
+    // InsertText(clang::SourceLocation, char const*, unsigned int).
+    // InsertText(startLoc, messString.c_str(), messString.size());
+    // Tried this, but it didn't work either...
+    // ReplaceText(startLoc, 0, messString.c_str(), messString.size());
+#endif
+    return RewriteMessageExpr(MessExpr);
+  }
+
+  if (ObjCAutoreleasePoolStmt *StmtAutoRelease = 
+        dyn_cast<ObjCAutoreleasePoolStmt>(S)) {
+    return RewriteObjCAutoreleasePoolStmt(StmtAutoRelease);
+  }
+  
+  if (ObjCAtTryStmt *StmtTry = dyn_cast<ObjCAtTryStmt>(S))
+    return RewriteObjCTryStmt(StmtTry);
+
+  if (ObjCAtSynchronizedStmt *StmtTry = dyn_cast<ObjCAtSynchronizedStmt>(S))
+    return RewriteObjCSynchronizedStmt(StmtTry);
+
+  if (ObjCAtThrowStmt *StmtThrow = dyn_cast<ObjCAtThrowStmt>(S))
+    return RewriteObjCThrowStmt(StmtThrow);
+
+  if (ObjCProtocolExpr *ProtocolExp = dyn_cast<ObjCProtocolExpr>(S))
+    return RewriteObjCProtocolExpr(ProtocolExp);
+
+  if (ObjCForCollectionStmt *StmtForCollection =
+        dyn_cast<ObjCForCollectionStmt>(S))
+    return RewriteObjCForCollectionStmt(StmtForCollection,
+                                        OrigStmtRange.getEnd());
+  if (BreakStmt *StmtBreakStmt =
+      dyn_cast<BreakStmt>(S))
+    return RewriteBreakStmt(StmtBreakStmt);
+  if (ContinueStmt *StmtContinueStmt =
+      dyn_cast<ContinueStmt>(S))
+    return RewriteContinueStmt(StmtContinueStmt);
+
+  // Need to check for protocol refs (id <P>, Foo <P> *) in variable decls
+  // and cast exprs.
+  if (DeclStmt *DS = dyn_cast<DeclStmt>(S)) {
+    // FIXME: What we're doing here is modifying the type-specifier that
+    // precedes the first Decl.  In the future the DeclGroup should have
+    // a separate type-specifier that we can rewrite.
+    // NOTE: We need to avoid rewriting the DeclStmt if it is within
+    // the context of an ObjCForCollectionStmt. For example:
+    //   NSArray *someArray;
+    //   for (id <FooProtocol> index in someArray) ;
+    // This is because RewriteObjCForCollectionStmt() does textual rewriting 
+    // and it depends on the original text locations/positions.
+    if (Stmts.empty() || !IsDeclStmtInForeachHeader(DS))
+      RewriteObjCQualifiedInterfaceTypes(*DS->decl_begin());
+
+    // Blocks rewrite rules.
+    for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end();
+         DI != DE; ++DI) {
+      Decl *SD = *DI;
+      if (ValueDecl *ND = dyn_cast<ValueDecl>(SD)) {
+        if (isTopLevelBlockPointerType(ND->getType()))
+          RewriteBlockPointerDecl(ND);
+        else if (ND->getType()->isFunctionPointerType())
+          CheckFunctionPointerDecl(ND->getType(), ND);
+        if (VarDecl *VD = dyn_cast<VarDecl>(SD)) {
+          if (VD->hasAttr<BlocksAttr>()) {
+            static unsigned uniqueByrefDeclCount = 0;
+            assert(!BlockByRefDeclNo.count(ND) &&
+              "RewriteFunctionBodyOrGlobalInitializer: Duplicate byref decl");
+            BlockByRefDeclNo[ND] = uniqueByrefDeclCount++;
+            RewriteByRefVar(VD, (DI == DS->decl_begin()), ((DI+1) == DE));
+          }
+          else           
+            RewriteTypeOfDecl(VD);
+        }
+      }
+      if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(SD)) {
+        if (isTopLevelBlockPointerType(TD->getUnderlyingType()))
+          RewriteBlockPointerDecl(TD);
+        else if (TD->getUnderlyingType()->isFunctionPointerType())
+          CheckFunctionPointerDecl(TD->getUnderlyingType(), TD);
+      }
+    }
+  }
+
+  if (CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(S))
+    RewriteObjCQualifiedInterfaceTypes(CE);
+
+  if (isa<SwitchStmt>(S) || isa<WhileStmt>(S) ||
+      isa<DoStmt>(S) || isa<ForStmt>(S)) {
+    assert(!Stmts.empty() && "Statement stack is empty");
+    assert ((isa<SwitchStmt>(Stmts.back()) || isa<WhileStmt>(Stmts.back()) ||
+             isa<DoStmt>(Stmts.back()) || isa<ForStmt>(Stmts.back()))
+            && "Statement stack mismatch");
+    Stmts.pop_back();
+  }
+  // Handle blocks rewriting.
+  if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(S)) {
+    ValueDecl *VD = DRE->getDecl(); 
+    if (VD->hasAttr<BlocksAttr>())
+      return RewriteBlockDeclRefExpr(DRE);
+    if (HasLocalVariableExternalStorage(VD))
+      return RewriteLocalVariableExternalStorage(DRE);
+  }
+  
+  if (CallExpr *CE = dyn_cast<CallExpr>(S)) {
+    if (CE->getCallee()->getType()->isBlockPointerType()) {
+      Stmt *BlockCall = SynthesizeBlockCall(CE, CE->getCallee());
+      ReplaceStmt(S, BlockCall);
+      return BlockCall;
+    }
+  }
+  if (CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(S)) {
+    RewriteCastExpr(CE);
+  }
+  if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(S)) {
+    RewriteImplicitCastObjCExpr(ICE);
+  }
+#if 0
+
+  if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(S)) {
+    CastExpr *Replacement = new (Context) CastExpr(ICE->getType(),
+                                                   ICE->getSubExpr(),
+                                                   SourceLocation());
+    // Get the new text.
+    std::string SStr;
+    llvm::raw_string_ostream Buf(SStr);
+    Replacement->printPretty(Buf);
+    const std::string &Str = Buf.str();
+
+    printf("CAST = %s\n", &Str[0]);
+    InsertText(ICE->getSubExpr()->getLocStart(), &Str[0], Str.size());
+    delete S;
+    return Replacement;
+  }
+#endif
+  // Return this stmt unmodified.
+  return S;
+}
+
+void RewriteModernObjC::RewriteRecordBody(RecordDecl *RD) {
+  for (auto *FD : RD->fields()) {
+    if (isTopLevelBlockPointerType(FD->getType()))
+      RewriteBlockPointerDecl(FD);
+    if (FD->getType()->isObjCQualifiedIdType() ||
+        FD->getType()->isObjCQualifiedInterfaceType())
+      RewriteObjCQualifiedInterfaceTypes(FD);
+  }
+}
+
+/// HandleDeclInMainFile - This is called for each top-level decl defined in the
+/// main file of the input.
+void RewriteModernObjC::HandleDeclInMainFile(Decl *D) {
+  switch (D->getKind()) {
+    case Decl::Function: {
+      FunctionDecl *FD = cast<FunctionDecl>(D);
+      if (FD->isOverloadedOperator())
+        return;
+
+      // Since function prototypes don't have ParmDecl's, we check the function
+      // prototype. This enables us to rewrite function declarations and
+      // definitions using the same code.
+      RewriteBlocksInFunctionProtoType(FD->getType(), FD);
+
+      if (!FD->isThisDeclarationADefinition())
+        break;
+
+      // FIXME: If this should support Obj-C++, support CXXTryStmt
+      if (CompoundStmt *Body = dyn_cast_or_null<CompoundStmt>(FD->getBody())) {
+        CurFunctionDef = FD;
+        CurrentBody = Body;
+        Body =
+        cast_or_null<CompoundStmt>(RewriteFunctionBodyOrGlobalInitializer(Body));
+        FD->setBody(Body);
+        CurrentBody = nullptr;
+        if (PropParentMap) {
+          delete PropParentMap;
+          PropParentMap = nullptr;
+        }
+        // This synthesizes and inserts the block "impl" struct, invoke function,
+        // and any copy/dispose helper functions.
+        InsertBlockLiteralsWithinFunction(FD);
+        RewriteLineDirective(D);
+        CurFunctionDef = nullptr;
+      }
+      break;
+    }
+    case Decl::ObjCMethod: {
+      ObjCMethodDecl *MD = cast<ObjCMethodDecl>(D);
+      if (CompoundStmt *Body = MD->getCompoundBody()) {
+        CurMethodDef = MD;
+        CurrentBody = Body;
+        Body =
+          cast_or_null<CompoundStmt>(RewriteFunctionBodyOrGlobalInitializer(Body));
+        MD->setBody(Body);
+        CurrentBody = nullptr;
+        if (PropParentMap) {
+          delete PropParentMap;
+          PropParentMap = nullptr;
+        }
+        InsertBlockLiteralsWithinMethod(MD);
+        RewriteLineDirective(D);
+        CurMethodDef = nullptr;
+      }
+      break;
+    }
+    case Decl::ObjCImplementation: {
+      ObjCImplementationDecl *CI = cast<ObjCImplementationDecl>(D);
+      ClassImplementation.push_back(CI);
+      break;
+    }
+    case Decl::ObjCCategoryImpl: {
+      ObjCCategoryImplDecl *CI = cast<ObjCCategoryImplDecl>(D);
+      CategoryImplementation.push_back(CI);
+      break;
+    }
+    case Decl::Var: {
+      VarDecl *VD = cast<VarDecl>(D);
+      RewriteObjCQualifiedInterfaceTypes(VD);
+      if (isTopLevelBlockPointerType(VD->getType()))
+        RewriteBlockPointerDecl(VD);
+      else if (VD->getType()->isFunctionPointerType()) {
+        CheckFunctionPointerDecl(VD->getType(), VD);
+        if (VD->getInit()) {
+          if (CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(VD->getInit())) {
+            RewriteCastExpr(CE);
+          }
+        }
+      } else if (VD->getType()->isRecordType()) {
+        RecordDecl *RD = VD->getType()->getAs<RecordType>()->getDecl();
+        if (RD->isCompleteDefinition())
+          RewriteRecordBody(RD);
+      }
+      if (VD->getInit()) {
+        GlobalVarDecl = VD;
+        CurrentBody = VD->getInit();
+        RewriteFunctionBodyOrGlobalInitializer(VD->getInit());
+        CurrentBody = nullptr;
+        if (PropParentMap) {
+          delete PropParentMap;
+          PropParentMap = nullptr;
+        }
+        SynthesizeBlockLiterals(VD->getTypeSpecStartLoc(), VD->getName());
+        GlobalVarDecl = nullptr;
+
+        // This is needed for blocks.
+        if (CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(VD->getInit())) {
+            RewriteCastExpr(CE);
+        }
+      }
+      break;
+    }
+    case Decl::TypeAlias:
+    case Decl::Typedef: {
+      if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(D)) {
+        if (isTopLevelBlockPointerType(TD->getUnderlyingType()))
+          RewriteBlockPointerDecl(TD);
+        else if (TD->getUnderlyingType()->isFunctionPointerType())
+          CheckFunctionPointerDecl(TD->getUnderlyingType(), TD);
+        else
+          RewriteObjCQualifiedInterfaceTypes(TD);
+      }
+      break;
+    }
+    case Decl::CXXRecord:
+    case Decl::Record: {
+      RecordDecl *RD = cast<RecordDecl>(D);
+      if (RD->isCompleteDefinition()) 
+        RewriteRecordBody(RD);
+      break;
+    }
+    default:
+      break;
+  }
+  // Nothing yet.
+}
+
+/// Write_ProtocolExprReferencedMetadata - This routine writer out the
+/// protocol reference symbols in the for of:
+/// struct _protocol_t *PROTOCOL_REF = &PROTOCOL_METADATA.
+static void Write_ProtocolExprReferencedMetadata(ASTContext *Context, 
+                                                 ObjCProtocolDecl *PDecl,
+                                                 std::string &Result) {
+  // Also output .objc_protorefs$B section and its meta-data.
+  if (Context->getLangOpts().MicrosoftExt)
+    Result += "static ";
+  Result += "struct _protocol_t *";
+  Result += "_OBJC_PROTOCOL_REFERENCE_$_";
+  Result += PDecl->getNameAsString();
+  Result += " = &";
+  Result += "_OBJC_PROTOCOL_"; Result += PDecl->getNameAsString();
+  Result += ";\n";
+}
+
+void RewriteModernObjC::HandleTranslationUnit(ASTContext &C) {
+  if (Diags.hasErrorOccurred())
+    return;
+
+  RewriteInclude();
+
+  for (unsigned i = 0, e = FunctionDefinitionsSeen.size(); i < e; i++) {
+    // translation of function bodies were postponed until all class and
+    // their extensions and implementations are seen. This is because, we
+    // cannot build grouping structs for bitfields until they are all seen.
+    FunctionDecl *FDecl = FunctionDefinitionsSeen[i];
+    HandleTopLevelSingleDecl(FDecl);
+  }
+
+  // Here's a great place to add any extra declarations that may be needed.
+  // Write out meta data for each @protocol(<expr>).
+  for (llvm::SmallPtrSet<ObjCProtocolDecl *,8>::iterator I = ProtocolExprDecls.begin(),
+       E = ProtocolExprDecls.end(); I != E; ++I) {
+    RewriteObjCProtocolMetaData(*I, Preamble);
+    Write_ProtocolExprReferencedMetadata(Context, (*I), Preamble);
+  }
+
+  InsertText(SM->getLocForStartOfFile(MainFileID), Preamble, false);
+  
+  if (ClassImplementation.size() || CategoryImplementation.size())
+    RewriteImplementations();
+  
+  for (unsigned i = 0, e = ObjCInterfacesSeen.size(); i < e; i++) {
+    ObjCInterfaceDecl *CDecl = ObjCInterfacesSeen[i];
+    // Write struct declaration for the class matching its ivar declarations.
+    // Note that for modern abi, this is postponed until the end of TU
+    // because class extensions and the implementation might declare their own
+    // private ivars.
+    RewriteInterfaceDecl(CDecl);
+  }
+  
+  // Get the buffer corresponding to MainFileID.  If we haven't changed it, then
+  // we are done.
+  if (const RewriteBuffer *RewriteBuf =
+      Rewrite.getRewriteBufferFor(MainFileID)) {
+    //printf("Changed:\n");
+    *OutFile << std::string(RewriteBuf->begin(), RewriteBuf->end());
+  } else {
+    llvm::errs() << "No changes\n";
+  }
+
+  if (ClassImplementation.size() || CategoryImplementation.size() ||
+      ProtocolExprDecls.size()) {
+    // Rewrite Objective-c meta data*
+    std::string ResultStr;
+    RewriteMetaDataIntoBuffer(ResultStr);
+    // Emit metadata.
+    *OutFile << ResultStr;
+  }
+  // Emit ImageInfo;
+  {
+    std::string ResultStr;
+    WriteImageInfo(ResultStr);
+    *OutFile << ResultStr;
+  }
+  OutFile->flush();
+}
+
+void RewriteModernObjC::Initialize(ASTContext &context) {
+  InitializeCommon(context);
+  
+  Preamble += "#ifndef __OBJC2__\n";
+  Preamble += "#define __OBJC2__\n";
+  Preamble += "#endif\n";
+
+  // declaring objc_selector outside the parameter list removes a silly
+  // scope related warning...
+  if (IsHeader)
+    Preamble = "#pragma once\n";
+  Preamble += "struct objc_selector; struct objc_class;\n";
+  Preamble += "struct __rw_objc_super { \n\tstruct objc_object *object; ";
+  Preamble += "\n\tstruct objc_object *superClass; ";
+  // Add a constructor for creating temporary objects.
+  Preamble += "\n\t__rw_objc_super(struct objc_object *o, struct objc_object *s) ";
+  Preamble += ": object(o), superClass(s) {} ";
+  Preamble += "\n};\n";
+  
+  if (LangOpts.MicrosoftExt) {
+    // Define all sections using syntax that makes sense.
+    // These are currently generated.
+    Preamble += "\n#pragma section(\".objc_classlist$B\", long, read, write)\n";
+    Preamble += "#pragma section(\".objc_catlist$B\", long, read, write)\n";
+    Preamble += "#pragma section(\".objc_imageinfo$B\", long, read, write)\n";
+    Preamble += "#pragma section(\".objc_nlclslist$B\", long, read, write)\n";
+    Preamble += "#pragma section(\".objc_nlcatlist$B\", long, read, write)\n";
+    // These are generated but not necessary for functionality.
+    Preamble += "#pragma section(\".cat_cls_meth$B\", long, read, write)\n";
+    Preamble += "#pragma section(\".inst_meth$B\", long, read, write)\n";
+    Preamble += "#pragma section(\".cls_meth$B\", long, read, write)\n";
+    Preamble += "#pragma section(\".objc_ivar$B\", long, read, write)\n";
+    
+    // These need be generated for performance. Currently they are not,
+    // using API calls instead.
+    Preamble += "#pragma section(\".objc_selrefs$B\", long, read, write)\n";
+    Preamble += "#pragma section(\".objc_classrefs$B\", long, read, write)\n";
+    Preamble += "#pragma section(\".objc_superrefs$B\", long, read, write)\n";
+    
+  }
+  Preamble += "#ifndef _REWRITER_typedef_Protocol\n";
+  Preamble += "typedef struct objc_object Protocol;\n";
+  Preamble += "#define _REWRITER_typedef_Protocol\n";
+  Preamble += "#endif\n";
+  if (LangOpts.MicrosoftExt) {
+    Preamble += "#define __OBJC_RW_DLLIMPORT extern \"C\" __declspec(dllimport)\n";
+    Preamble += "#define __OBJC_RW_STATICIMPORT extern \"C\"\n";
+  } 
+  else
+    Preamble += "#define __OBJC_RW_DLLIMPORT extern\n";
+  
+  Preamble += "__OBJC_RW_DLLIMPORT void objc_msgSend(void);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT void objc_msgSendSuper(void);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT void objc_msgSend_stret(void);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT void objc_msgSendSuper_stret(void);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT void objc_msgSend_fpret(void);\n";
+
+  Preamble += "__OBJC_RW_DLLIMPORT struct objc_class *objc_getClass";
+  Preamble += "(const char *);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT struct objc_class *class_getSuperclass";
+  Preamble += "(struct objc_class *);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT struct objc_class *objc_getMetaClass";
+  Preamble += "(const char *);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT void objc_exception_throw( struct objc_object *);\n";
+  // @synchronized hooks.
+  Preamble += "__OBJC_RW_DLLIMPORT int objc_sync_enter( struct objc_object *);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT int objc_sync_exit( struct objc_object *);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT Protocol *objc_getProtocol(const char *);\n";
+  Preamble += "#ifdef _WIN64\n";
+  Preamble += "typedef unsigned long long  _WIN_NSUInteger;\n";
+  Preamble += "#else\n";
+  Preamble += "typedef unsigned int _WIN_NSUInteger;\n";
+  Preamble += "#endif\n";
+  Preamble += "#ifndef __FASTENUMERATIONSTATE\n";
+  Preamble += "struct __objcFastEnumerationState {\n\t";
+  Preamble += "unsigned long state;\n\t";
+  Preamble += "void **itemsPtr;\n\t";
+  Preamble += "unsigned long *mutationsPtr;\n\t";
+  Preamble += "unsigned long extra[5];\n};\n";
+  Preamble += "__OBJC_RW_DLLIMPORT void objc_enumerationMutation(struct objc_object *);\n";
+  Preamble += "#define __FASTENUMERATIONSTATE\n";
+  Preamble += "#endif\n";
+  Preamble += "#ifndef __NSCONSTANTSTRINGIMPL\n";
+  Preamble += "struct __NSConstantStringImpl {\n";
+  Preamble += "  int *isa;\n";
+  Preamble += "  int flags;\n";
+  Preamble += "  char *str;\n";
+  Preamble += "#if _WIN64\n";
+  Preamble += "  long long length;\n";
+  Preamble += "#else\n";
+  Preamble += "  long length;\n";
+  Preamble += "#endif\n";
+  Preamble += "};\n";
+  Preamble += "#ifdef CF_EXPORT_CONSTANT_STRING\n";
+  Preamble += "extern \"C\" __declspec(dllexport) int __CFConstantStringClassReference[];\n";
+  Preamble += "#else\n";
+  Preamble += "__OBJC_RW_DLLIMPORT int __CFConstantStringClassReference[];\n";
+  Preamble += "#endif\n";
+  Preamble += "#define __NSCONSTANTSTRINGIMPL\n";
+  Preamble += "#endif\n";
+  // Blocks preamble.
+  Preamble += "#ifndef BLOCK_IMPL\n";
+  Preamble += "#define BLOCK_IMPL\n";
+  Preamble += "struct __block_impl {\n";
+  Preamble += "  void *isa;\n";
+  Preamble += "  int Flags;\n";
+  Preamble += "  int Reserved;\n";
+  Preamble += "  void *FuncPtr;\n";
+  Preamble += "};\n";
+  Preamble += "// Runtime copy/destroy helper functions (from Block_private.h)\n";
+  Preamble += "#ifdef __OBJC_EXPORT_BLOCKS\n";
+  Preamble += "extern \"C\" __declspec(dllexport) "
+  "void _Block_object_assign(void *, const void *, const int);\n";
+  Preamble += "extern \"C\" __declspec(dllexport) void _Block_object_dispose(const void *, const int);\n";
+  Preamble += "extern \"C\" __declspec(dllexport) void *_NSConcreteGlobalBlock[32];\n";
+  Preamble += "extern \"C\" __declspec(dllexport) void *_NSConcreteStackBlock[32];\n";
+  Preamble += "#else\n";
+  Preamble += "__OBJC_RW_DLLIMPORT void _Block_object_assign(void *, const void *, const int);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT void _Block_object_dispose(const void *, const int);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT void *_NSConcreteGlobalBlock[32];\n";
+  Preamble += "__OBJC_RW_DLLIMPORT void *_NSConcreteStackBlock[32];\n";
+  Preamble += "#endif\n";
+  Preamble += "#endif\n";
+  if (LangOpts.MicrosoftExt) {
+    Preamble += "#undef __OBJC_RW_DLLIMPORT\n";
+    Preamble += "#undef __OBJC_RW_STATICIMPORT\n";
+    Preamble += "#ifndef KEEP_ATTRIBUTES\n";  // We use this for clang tests.
+    Preamble += "#define __attribute__(X)\n";
+    Preamble += "#endif\n";
+    Preamble += "#ifndef __weak\n";
+    Preamble += "#define __weak\n";
+    Preamble += "#endif\n";
+    Preamble += "#ifndef __block\n";
+    Preamble += "#define __block\n";
+    Preamble += "#endif\n";
+  }
+  else {
+    Preamble += "#define __block\n";
+    Preamble += "#define __weak\n";
+  }
+  
+  // Declarations required for modern objective-c array and dictionary literals.
+  Preamble += "\n#include <stdarg.h>\n";
+  Preamble += "struct __NSContainer_literal {\n";
+  Preamble += "  void * *arr;\n";
+  Preamble += "  __NSContainer_literal (unsigned int count, ...) {\n";
+  Preamble += "\tva_list marker;\n";
+  Preamble += "\tva_start(marker, count);\n";
+  Preamble += "\tarr = new void *[count];\n";
+  Preamble += "\tfor (unsigned i = 0; i < count; i++)\n";
+  Preamble += "\t  arr[i] = va_arg(marker, void *);\n";
+  Preamble += "\tva_end( marker );\n";
+  Preamble += "  };\n";
+  Preamble += "  ~__NSContainer_literal() {\n";
+  Preamble += "\tdelete[] arr;\n";
+  Preamble += "  }\n";
+  Preamble += "};\n";
+  
+  // Declaration required for implementation of @autoreleasepool statement.
+  Preamble += "extern \"C\" __declspec(dllimport) void * objc_autoreleasePoolPush(void);\n";
+  Preamble += "extern \"C\" __declspec(dllimport) void objc_autoreleasePoolPop(void *);\n\n";
+  Preamble += "struct __AtAutoreleasePool {\n";
+  Preamble += "  __AtAutoreleasePool() {atautoreleasepoolobj = objc_autoreleasePoolPush();}\n";
+  Preamble += "  ~__AtAutoreleasePool() {objc_autoreleasePoolPop(atautoreleasepoolobj);}\n";
+  Preamble += "  void * atautoreleasepoolobj;\n";
+  Preamble += "};\n";
+  
+  // NOTE! Windows uses LLP64 for 64bit mode. So, cast pointer to long long
+  // as this avoids warning in any 64bit/32bit compilation model.
+  Preamble += "\n#define __OFFSETOFIVAR__(TYPE, MEMBER) ((long long) &((TYPE *)0)->MEMBER)\n";
+}
+
+/// RewriteIvarOffsetComputation - This rutine synthesizes computation of
+/// ivar offset.
+void RewriteModernObjC::RewriteIvarOffsetComputation(ObjCIvarDecl *ivar,
+                                                         std::string &Result) {
+  Result += "__OFFSETOFIVAR__(struct ";
+  Result += ivar->getContainingInterface()->getNameAsString();
+  if (LangOpts.MicrosoftExt)
+    Result += "_IMPL";
+  Result += ", ";
+  if (ivar->isBitField())
+    ObjCIvarBitfieldGroupDecl(ivar, Result);
+  else
+    Result += ivar->getNameAsString();
+  Result += ")";
+}
+
+/// WriteModernMetadataDeclarations - Writes out metadata declarations for modern ABI.
+/// struct _prop_t {
+///   const char *name;
+///   char *attributes;
+/// }
+
+/// struct _prop_list_t {
+///   uint32_t entsize;      // sizeof(struct _prop_t)
+///   uint32_t count_of_properties;
+///   struct _prop_t prop_list[count_of_properties];
+/// }
+
+/// struct _protocol_t;
+
+/// struct _protocol_list_t {
+///   long protocol_count;   // Note, this is 32/64 bit
+///   struct _protocol_t * protocol_list[protocol_count];
+/// }
+
+/// struct _objc_method {
+///   SEL _cmd;
+///   const char *method_type;
+///   char *_imp;
+/// }
+
+/// struct _method_list_t {
+///   uint32_t entsize;  // sizeof(struct _objc_method)
+///   uint32_t method_count;
+///   struct _objc_method method_list[method_count];
+/// }
+
+/// struct _protocol_t {
+///   id isa;  // NULL
+///   const char *protocol_name;
+///   const struct _protocol_list_t * protocol_list; // super protocols
+///   const struct method_list_t *instance_methods;
+///   const struct method_list_t *class_methods;
+///   const struct method_list_t *optionalInstanceMethods;
+///   const struct method_list_t *optionalClassMethods;
+///   const struct _prop_list_t * properties;
+///   const uint32_t size;  // sizeof(struct _protocol_t)
+///   const uint32_t flags;  // = 0
+///   const char ** extendedMethodTypes;
+/// }
+
+/// struct _ivar_t {
+///   unsigned long int *offset;  // pointer to ivar offset location
+///   const char *name;
+///   const char *type;
+///   uint32_t alignment;
+///   uint32_t size;
+/// }
+
+/// struct _ivar_list_t {
+///   uint32 entsize;  // sizeof(struct _ivar_t)
+///   uint32 count;
+///   struct _ivar_t list[count];
+/// }
+
+/// struct _class_ro_t {
+///   uint32_t flags;
+///   uint32_t instanceStart;
+///   uint32_t instanceSize;
+///   uint32_t reserved;  // only when building for 64bit targets
+///   const uint8_t *ivarLayout;
+///   const char *name;
+///   const struct _method_list_t *baseMethods;
+///   const struct _protocol_list_t *baseProtocols;
+///   const struct _ivar_list_t *ivars;
+///   const uint8_t *weakIvarLayout;
+///   const struct _prop_list_t *properties;
+/// }
+
+/// struct _class_t {
+///   struct _class_t *isa;
+///   struct _class_t *superclass;
+///   void *cache;
+///   IMP *vtable;
+///   struct _class_ro_t *ro;
+/// }
+
+/// struct _category_t {
+///   const char *name;
+///   struct _class_t *cls;
+///   const struct _method_list_t *instance_methods;
+///   const struct _method_list_t *class_methods;
+///   const struct _protocol_list_t *protocols;
+///   const struct _prop_list_t *properties;
+/// }
+
+/// MessageRefTy - LLVM for:
+/// struct _message_ref_t {
+///   IMP messenger;
+///   SEL name;
+/// };
+
+/// SuperMessageRefTy - LLVM for:
+/// struct _super_message_ref_t {
+///   SUPER_IMP messenger;
+///   SEL name;
+/// };
+
+static void WriteModernMetadataDeclarations(ASTContext *Context, std::string &Result) {
+  static bool meta_data_declared = false;
+  if (meta_data_declared)
+    return;
+  
+  Result += "\nstruct _prop_t {\n";
+  Result += "\tconst char *name;\n";
+  Result += "\tconst char *attributes;\n";
+  Result += "};\n";
+  
+  Result += "\nstruct _protocol_t;\n";
+  
+  Result += "\nstruct _objc_method {\n";
+  Result += "\tstruct objc_selector * _cmd;\n";
+  Result += "\tconst char *method_type;\n";
+  Result += "\tvoid  *_imp;\n";
+  Result += "};\n";
+  
+  Result += "\nstruct _protocol_t {\n";
+  Result += "\tvoid * isa;  // NULL\n";
+  Result += "\tconst char *protocol_name;\n";
+  Result += "\tconst struct _protocol_list_t * protocol_list; // super protocols\n";
+  Result += "\tconst struct method_list_t *instance_methods;\n";
+  Result += "\tconst struct method_list_t *class_methods;\n";
+  Result += "\tconst struct method_list_t *optionalInstanceMethods;\n";
+  Result += "\tconst struct method_list_t *optionalClassMethods;\n";
+  Result += "\tconst struct _prop_list_t * properties;\n";
+  Result += "\tconst unsigned int size;  // sizeof(struct _protocol_t)\n";
+  Result += "\tconst unsigned int flags;  // = 0\n";
+  Result += "\tconst char ** extendedMethodTypes;\n";
+  Result += "};\n";
+  
+  Result += "\nstruct _ivar_t {\n";
+  Result += "\tunsigned long int *offset;  // pointer to ivar offset location\n";
+  Result += "\tconst char *name;\n";
+  Result += "\tconst char *type;\n";
+  Result += "\tunsigned int alignment;\n";
+  Result += "\tunsigned int  size;\n";
+  Result += "};\n";
+  
+  Result += "\nstruct _class_ro_t {\n";
+  Result += "\tunsigned int flags;\n";
+  Result += "\tunsigned int instanceStart;\n";
+  Result += "\tunsigned int instanceSize;\n";
+  const llvm::Triple &Triple(Context->getTargetInfo().getTriple());
+  if (Triple.getArch() == llvm::Triple::x86_64)
+    Result += "\tunsigned int reserved;\n";
+  Result += "\tconst unsigned char *ivarLayout;\n";
+  Result += "\tconst char *name;\n";
+  Result += "\tconst struct _method_list_t *baseMethods;\n";
+  Result += "\tconst struct _objc_protocol_list *baseProtocols;\n";
+  Result += "\tconst struct _ivar_list_t *ivars;\n";
+  Result += "\tconst unsigned char *weakIvarLayout;\n";
+  Result += "\tconst struct _prop_list_t *properties;\n";
+  Result += "};\n";
+  
+  Result += "\nstruct _class_t {\n";
+  Result += "\tstruct _class_t *isa;\n";
+  Result += "\tstruct _class_t *superclass;\n";
+  Result += "\tvoid *cache;\n";
+  Result += "\tvoid *vtable;\n";
+  Result += "\tstruct _class_ro_t *ro;\n";
+  Result += "};\n";
+  
+  Result += "\nstruct _category_t {\n";
+  Result += "\tconst char *name;\n";
+  Result += "\tstruct _class_t *cls;\n";
+  Result += "\tconst struct _method_list_t *instance_methods;\n";
+  Result += "\tconst struct _method_list_t *class_methods;\n";
+  Result += "\tconst struct _protocol_list_t *protocols;\n";
+  Result += "\tconst struct _prop_list_t *properties;\n";
+  Result += "};\n";
+  
+  Result += "extern \"C\" __declspec(dllimport) struct objc_cache _objc_empty_cache;\n";
+  Result += "#pragma warning(disable:4273)\n";
+  meta_data_declared = true;
+}
+
+static void Write_protocol_list_t_TypeDecl(std::string &Result,
+                                           long super_protocol_count) {
+  Result += "struct /*_protocol_list_t*/"; Result += " {\n";
+  Result += "\tlong protocol_count;  // Note, this is 32/64 bit\n";
+  Result += "\tstruct _protocol_t *super_protocols[";
+  Result += utostr(super_protocol_count); Result += "];\n";
+  Result += "}";
+}
+
+static void Write_method_list_t_TypeDecl(std::string &Result,
+                                         unsigned int method_count) {
+  Result += "struct /*_method_list_t*/"; Result += " {\n";
+  Result += "\tunsigned int entsize;  // sizeof(struct _objc_method)\n";
+  Result += "\tunsigned int method_count;\n";
+  Result += "\tstruct _objc_method method_list[";
+  Result += utostr(method_count); Result += "];\n";
+  Result += "}";
+}
+
+static void Write__prop_list_t_TypeDecl(std::string &Result,
+                                        unsigned int property_count) {
+  Result += "struct /*_prop_list_t*/"; Result += " {\n";
+  Result += "\tunsigned int entsize;  // sizeof(struct _prop_t)\n";
+  Result += "\tunsigned int count_of_properties;\n";
+  Result += "\tstruct _prop_t prop_list[";
+  Result += utostr(property_count); Result += "];\n";
+  Result += "}";
+}
+
+static void Write__ivar_list_t_TypeDecl(std::string &Result,
+                                        unsigned int ivar_count) {
+  Result += "struct /*_ivar_list_t*/"; Result += " {\n";
+  Result += "\tunsigned int entsize;  // sizeof(struct _prop_t)\n";
+  Result += "\tunsigned int count;\n";
+  Result += "\tstruct _ivar_t ivar_list[";
+  Result += utostr(ivar_count); Result += "];\n";
+  Result += "}";
+}
+
+static void Write_protocol_list_initializer(ASTContext *Context, std::string &Result,
+                                            ArrayRef<ObjCProtocolDecl *> SuperProtocols,
+                                            StringRef VarName,
+                                            StringRef ProtocolName) {
+  if (SuperProtocols.size() > 0) {
+    Result += "\nstatic ";
+    Write_protocol_list_t_TypeDecl(Result, SuperProtocols.size());
+    Result += " "; Result += VarName;
+    Result += ProtocolName; 
+    Result += " __attribute__ ((used, section (\"__DATA,__objc_const\"))) = {\n";
+    Result += "\t"; Result += utostr(SuperProtocols.size()); Result += ",\n";
+    for (unsigned i = 0, e = SuperProtocols.size(); i < e; i++) {
+      ObjCProtocolDecl *SuperPD = SuperProtocols[i];
+      Result += "\t&"; Result += "_OBJC_PROTOCOL_"; 
+      Result += SuperPD->getNameAsString();
+      if (i == e-1)
+        Result += "\n};\n";
+      else
+        Result += ",\n";
+    }
+  }
+}
+
+static void Write_method_list_t_initializer(RewriteModernObjC &RewriteObj,
+                                            ASTContext *Context, std::string &Result,
+                                            ArrayRef<ObjCMethodDecl *> Methods,
+                                            StringRef VarName,
+                                            StringRef TopLevelDeclName,
+                                            bool MethodImpl) {
+  if (Methods.size() > 0) {
+    Result += "\nstatic ";
+    Write_method_list_t_TypeDecl(Result, Methods.size());
+    Result += " "; Result += VarName;
+    Result += TopLevelDeclName; 
+    Result += " __attribute__ ((used, section (\"__DATA,__objc_const\"))) = {\n";
+    Result += "\t"; Result += "sizeof(_objc_method)"; Result += ",\n";
+    Result += "\t"; Result += utostr(Methods.size()); Result += ",\n";
+    for (unsigned i = 0, e = Methods.size(); i < e; i++) {
+      ObjCMethodDecl *MD = Methods[i];
+      if (i == 0)
+        Result += "\t{{(struct objc_selector *)\"";
+      else
+        Result += "\t{(struct objc_selector *)\"";
+      Result += (MD)->getSelector().getAsString(); Result += "\"";
+      Result += ", ";
+      std::string MethodTypeString;
+      Context->getObjCEncodingForMethodDecl(MD, MethodTypeString);
+      Result += "\""; Result += MethodTypeString; Result += "\"";
+      Result += ", ";
+      if (!MethodImpl)
+        Result += "0";
+      else {
+        Result += "(void *)";
+        Result += RewriteObj.MethodInternalNames[MD];
+      }
+      if (i  == e-1)
+        Result += "}}\n";
+      else
+        Result += "},\n";
+    }
+    Result += "};\n";
+  }
+}
+
+static void Write_prop_list_t_initializer(RewriteModernObjC &RewriteObj,
+                                           ASTContext *Context, std::string &Result,
+                                           ArrayRef<ObjCPropertyDecl *> Properties,
+                                           const Decl *Container,
+                                           StringRef VarName,
+                                           StringRef ProtocolName) {
+  if (Properties.size() > 0) {
+    Result += "\nstatic ";
+    Write__prop_list_t_TypeDecl(Result, Properties.size());
+    Result += " "; Result += VarName;
+    Result += ProtocolName; 
+    Result += " __attribute__ ((used, section (\"__DATA,__objc_const\"))) = {\n";
+    Result += "\t"; Result += "sizeof(_prop_t)"; Result += ",\n";
+    Result += "\t"; Result += utostr(Properties.size()); Result += ",\n";
+    for (unsigned i = 0, e = Properties.size(); i < e; i++) {
+      ObjCPropertyDecl *PropDecl = Properties[i];
+      if (i == 0)
+        Result += "\t{{\"";
+      else
+        Result += "\t{\"";
+      Result += PropDecl->getName(); Result += "\",";
+      std::string PropertyTypeString, QuotePropertyTypeString;
+      Context->getObjCEncodingForPropertyDecl(PropDecl, Container, PropertyTypeString);
+      RewriteObj.QuoteDoublequotes(PropertyTypeString, QuotePropertyTypeString);
+      Result += "\""; Result += QuotePropertyTypeString; Result += "\"";
+      if (i  == e-1)
+        Result += "}}\n";
+      else
+        Result += "},\n";
+    }
+    Result += "};\n";
+  }
+}
+
+// Metadata flags
+enum MetaDataDlags {
+  CLS = 0x0,
+  CLS_META = 0x1,
+  CLS_ROOT = 0x2,
+  OBJC2_CLS_HIDDEN = 0x10,
+  CLS_EXCEPTION = 0x20,
+  
+  /// (Obsolete) ARC-specific: this class has a .release_ivars method
+  CLS_HAS_IVAR_RELEASER = 0x40,
+  /// class was compiled with -fobjc-arr
+  CLS_COMPILED_BY_ARC = 0x80  // (1<<7)
+};
+
+static void Write__class_ro_t_initializer(ASTContext *Context, std::string &Result, 
+                                          unsigned int flags, 
+                                          const std::string &InstanceStart, 
+                                          const std::string &InstanceSize,
+                                          ArrayRef<ObjCMethodDecl *>baseMethods,
+                                          ArrayRef<ObjCProtocolDecl *>baseProtocols,
+                                          ArrayRef<ObjCIvarDecl *>ivars,
+                                          ArrayRef<ObjCPropertyDecl *>Properties,
+                                          StringRef VarName,
+                                          StringRef ClassName) {
+  Result += "\nstatic struct _class_ro_t ";
+  Result += VarName; Result += ClassName;
+  Result += " __attribute__ ((used, section (\"__DATA,__objc_const\"))) = {\n";
+  Result += "\t"; 
+  Result += llvm::utostr(flags); Result += ", "; 
+  Result += InstanceStart; Result += ", ";
+  Result += InstanceSize; Result += ", \n";
+  Result += "\t";
+  const llvm::Triple &Triple(Context->getTargetInfo().getTriple());
+  if (Triple.getArch() == llvm::Triple::x86_64)
+    // uint32_t const reserved; // only when building for 64bit targets
+    Result += "(unsigned int)0, \n\t";
+  // const uint8_t * const ivarLayout;
+  Result += "0, \n\t";
+  Result += "\""; Result += ClassName; Result += "\",\n\t";
+  bool metaclass = ((flags & CLS_META) != 0);
+  if (baseMethods.size() > 0) {
+    Result += "(const struct _method_list_t *)&";
+    if (metaclass)
+      Result += "_OBJC_$_CLASS_METHODS_";
+    else
+      Result += "_OBJC_$_INSTANCE_METHODS_";
+    Result += ClassName;
+    Result += ",\n\t";
+  }
+  else
+    Result += "0, \n\t";
+
+  if (!metaclass && baseProtocols.size() > 0) {
+    Result += "(const struct _objc_protocol_list *)&";
+    Result += "_OBJC_CLASS_PROTOCOLS_$_"; Result += ClassName;
+    Result += ",\n\t";
+  }
+  else
+    Result += "0, \n\t";
+
+  if (!metaclass && ivars.size() > 0) {
+    Result += "(const struct _ivar_list_t *)&";
+    Result += "_OBJC_$_INSTANCE_VARIABLES_"; Result += ClassName;
+    Result += ",\n\t";
+  }
+  else
+    Result += "0, \n\t";
+
+  // weakIvarLayout
+  Result += "0, \n\t";
+  if (!metaclass && Properties.size() > 0) {
+    Result += "(const struct _prop_list_t *)&";
+    Result += "_OBJC_$_PROP_LIST_"; Result += ClassName;
+    Result += ",\n";
+  }
+  else
+    Result += "0, \n";
+
+  Result += "};\n";
+}
+
+static void Write_class_t(ASTContext *Context, std::string &Result,
+                          StringRef VarName,
+                          const ObjCInterfaceDecl *CDecl, bool metaclass) {
+  bool rootClass = (!CDecl->getSuperClass());
+  const ObjCInterfaceDecl *RootClass = CDecl;
+  
+  if (!rootClass) {
+    // Find the Root class
+    RootClass = CDecl->getSuperClass();
+    while (RootClass->getSuperClass()) {
+      RootClass = RootClass->getSuperClass();
+    }
+  }
+
+  if (metaclass && rootClass) {
+    // Need to handle a case of use of forward declaration.
+    Result += "\n";
+    Result += "extern \"C\" ";
+    if (CDecl->getImplementation())
+      Result += "__declspec(dllexport) ";
+    else
+      Result += "__declspec(dllimport) ";
+    
+    Result += "struct _class_t OBJC_CLASS_$_";
+    Result += CDecl->getNameAsString();
+    Result += ";\n";
+  }
+  // Also, for possibility of 'super' metadata class not having been defined yet.
+  if (!rootClass) {
+    ObjCInterfaceDecl *SuperClass = CDecl->getSuperClass();
+    Result += "\n";
+    Result += "extern \"C\" ";
+    if (SuperClass->getImplementation())
+      Result += "__declspec(dllexport) ";
+    else
+      Result += "__declspec(dllimport) ";
+
+    Result += "struct _class_t "; 
+    Result += VarName;
+    Result += SuperClass->getNameAsString();
+    Result += ";\n";
+    
+    if (metaclass && RootClass != SuperClass) {
+      Result += "extern \"C\" ";
+      if (RootClass->getImplementation())
+        Result += "__declspec(dllexport) ";
+      else
+        Result += "__declspec(dllimport) ";
+
+      Result += "struct _class_t "; 
+      Result += VarName;
+      Result += RootClass->getNameAsString();
+      Result += ";\n";
+    }
+  }
+  
+  Result += "\nextern \"C\" __declspec(dllexport) struct _class_t "; 
+  Result += VarName; Result += CDecl->getNameAsString();
+  Result += " __attribute__ ((used, section (\"__DATA,__objc_data\"))) = {\n";
+  Result += "\t";
+  if (metaclass) {
+    if (!rootClass) {
+      Result += "0, // &"; Result += VarName;
+      Result += RootClass->getNameAsString();
+      Result += ",\n\t";
+      Result += "0, // &"; Result += VarName;
+      Result += CDecl->getSuperClass()->getNameAsString();
+      Result += ",\n\t";
+    }
+    else {
+      Result += "0, // &"; Result += VarName; 
+      Result += CDecl->getNameAsString();
+      Result += ",\n\t";
+      Result += "0, // &OBJC_CLASS_$_"; Result += CDecl->getNameAsString();
+      Result += ",\n\t";
+    }
+  }
+  else {
+    Result += "0, // &OBJC_METACLASS_$_"; 
+    Result += CDecl->getNameAsString();
+    Result += ",\n\t";
+    if (!rootClass) {
+      Result += "0, // &"; Result += VarName;
+      Result += CDecl->getSuperClass()->getNameAsString();
+      Result += ",\n\t";
+    }
+    else 
+      Result += "0,\n\t";
+  }
+  Result += "0, // (void *)&_objc_empty_cache,\n\t";
+  Result += "0, // unused, was (void *)&_objc_empty_vtable,\n\t";
+  if (metaclass)
+    Result += "&_OBJC_METACLASS_RO_$_";
+  else
+    Result += "&_OBJC_CLASS_RO_$_";
+  Result += CDecl->getNameAsString();
+  Result += ",\n};\n";
+  
+  // Add static function to initialize some of the meta-data fields.
+  // avoid doing it twice.
+  if (metaclass)
+    return;
+  
+  const ObjCInterfaceDecl *SuperClass = 
+    rootClass ? CDecl : CDecl->getSuperClass();
+  
+  Result += "static void OBJC_CLASS_SETUP_$_";
+  Result += CDecl->getNameAsString();
+  Result += "(void ) {\n";
+  Result += "\tOBJC_METACLASS_$_"; Result += CDecl->getNameAsString();
+  Result += ".isa = "; Result += "&OBJC_METACLASS_$_";
+  Result += RootClass->getNameAsString(); Result += ";\n";
+  
+  Result += "\tOBJC_METACLASS_$_"; Result += CDecl->getNameAsString();
+  Result += ".superclass = ";
+  if (rootClass)
+    Result += "&OBJC_CLASS_$_";
+  else
+     Result += "&OBJC_METACLASS_$_";
+
+  Result += SuperClass->getNameAsString(); Result += ";\n";
+  
+  Result += "\tOBJC_METACLASS_$_"; Result += CDecl->getNameAsString();
+  Result += ".cache = "; Result += "&_objc_empty_cache"; Result += ";\n";
+  
+  Result += "\tOBJC_CLASS_$_"; Result += CDecl->getNameAsString();
+  Result += ".isa = "; Result += "&OBJC_METACLASS_$_";
+  Result += CDecl->getNameAsString(); Result += ";\n";
+  
+  if (!rootClass) {
+    Result += "\tOBJC_CLASS_$_"; Result += CDecl->getNameAsString();
+    Result += ".superclass = "; Result += "&OBJC_CLASS_$_";
+    Result += SuperClass->getNameAsString(); Result += ";\n";
+  }
+  
+  Result += "\tOBJC_CLASS_$_"; Result += CDecl->getNameAsString();
+  Result += ".cache = "; Result += "&_objc_empty_cache"; Result += ";\n";
+  Result += "}\n";
+}
+
+static void Write_category_t(RewriteModernObjC &RewriteObj, ASTContext *Context, 
+                             std::string &Result,
+                             ObjCCategoryDecl *CatDecl,
+                             ObjCInterfaceDecl *ClassDecl,
+                             ArrayRef<ObjCMethodDecl *> InstanceMethods,
+                             ArrayRef<ObjCMethodDecl *> ClassMethods,
+                             ArrayRef<ObjCProtocolDecl *> RefedProtocols,
+                             ArrayRef<ObjCPropertyDecl *> ClassProperties) {
+  StringRef CatName = CatDecl->getName();
+  StringRef ClassName = ClassDecl->getName();
+  // must declare an extern class object in case this class is not implemented 
+  // in this TU.
+  Result += "\n";
+  Result += "extern \"C\" ";
+  if (ClassDecl->getImplementation())
+    Result += "__declspec(dllexport) ";
+  else
+    Result += "__declspec(dllimport) ";
+  
+  Result += "struct _class_t ";
+  Result += "OBJC_CLASS_$_"; Result += ClassName;
+  Result += ";\n";
+  
+  Result += "\nstatic struct _category_t ";
+  Result += "_OBJC_$_CATEGORY_";
+  Result += ClassName; Result += "_$_"; Result += CatName;
+  Result += " __attribute__ ((used, section (\"__DATA,__objc_const\"))) = \n";
+  Result += "{\n";
+  Result += "\t\""; Result += ClassName; Result += "\",\n";
+  Result += "\t0, // &"; Result += "OBJC_CLASS_$_"; Result += ClassName;
+  Result += ",\n";
+  if (InstanceMethods.size() > 0) {
+    Result += "\t(const struct _method_list_t *)&";  
+    Result += "_OBJC_$_CATEGORY_INSTANCE_METHODS_";
+    Result += ClassName; Result += "_$_"; Result += CatName;
+    Result += ",\n";
+  }
+  else
+    Result += "\t0,\n";
+  
+  if (ClassMethods.size() > 0) {
+    Result += "\t(const struct _method_list_t *)&";  
+    Result += "_OBJC_$_CATEGORY_CLASS_METHODS_";
+    Result += ClassName; Result += "_$_"; Result += CatName;
+    Result += ",\n";
+  }
+  else
+    Result += "\t0,\n";
+  
+  if (RefedProtocols.size() > 0) {
+    Result += "\t(const struct _protocol_list_t *)&";  
+    Result += "_OBJC_CATEGORY_PROTOCOLS_$_";
+    Result += ClassName; Result += "_$_"; Result += CatName;
+    Result += ",\n";
+  }
+  else
+    Result += "\t0,\n";
+  
+  if (ClassProperties.size() > 0) {
+    Result += "\t(const struct _prop_list_t *)&";  Result += "_OBJC_$_PROP_LIST_";
+    Result += ClassName; Result += "_$_"; Result += CatName;
+    Result += ",\n";
+  }
+  else
+    Result += "\t0,\n";
+  
+  Result += "};\n";
+  
+  // Add static function to initialize the class pointer in the category structure.
+  Result += "static void OBJC_CATEGORY_SETUP_$_";
+  Result += ClassDecl->getNameAsString();
+  Result += "_$_";
+  Result += CatName;
+  Result += "(void ) {\n";
+  Result += "\t_OBJC_$_CATEGORY_"; 
+  Result += ClassDecl->getNameAsString();
+  Result += "_$_";
+  Result += CatName;
+  Result += ".cls = "; Result += "&OBJC_CLASS_$_"; Result += ClassName;
+  Result += ";\n}\n";
+}
+
+static void Write__extendedMethodTypes_initializer(RewriteModernObjC &RewriteObj,
+                                           ASTContext *Context, std::string &Result,
+                                           ArrayRef<ObjCMethodDecl *> Methods,
+                                           StringRef VarName,
+                                           StringRef ProtocolName) {
+  if (Methods.size() == 0)
+    return;
+  
+  Result += "\nstatic const char *";
+  Result += VarName; Result += ProtocolName;
+  Result += " [] __attribute__ ((used, section (\"__DATA,__objc_const\"))) = \n";
+  Result += "{\n";
+  for (unsigned i = 0, e = Methods.size(); i < e; i++) {
+    ObjCMethodDecl *MD = Methods[i];
+    std::string MethodTypeString, QuoteMethodTypeString;
+    Context->getObjCEncodingForMethodDecl(MD, MethodTypeString, true);
+    RewriteObj.QuoteDoublequotes(MethodTypeString, QuoteMethodTypeString);
+    Result += "\t\""; Result += QuoteMethodTypeString; Result += "\"";
+    if (i == e-1)
+      Result += "\n};\n";
+    else {
+      Result += ",\n";
+    }
+  }
+}
+
+static void Write_IvarOffsetVar(RewriteModernObjC &RewriteObj,
+                                ASTContext *Context,
+                                std::string &Result, 
+                                ArrayRef<ObjCIvarDecl *> Ivars, 
+                                ObjCInterfaceDecl *CDecl) {
+  // FIXME. visibilty of offset symbols may have to be set; for Darwin
+  // this is what happens:
+  /**
+   if (Ivar->getAccessControl() == ObjCIvarDecl::Private ||
+       Ivar->getAccessControl() == ObjCIvarDecl::Package ||
+       Class->getVisibility() == HiddenVisibility)
+     Visibility shoud be: HiddenVisibility;
+   else
+     Visibility shoud be: DefaultVisibility;
+  */
+  
+  Result += "\n";
+  for (unsigned i =0, e = Ivars.size(); i < e; i++) {
+    ObjCIvarDecl *IvarDecl = Ivars[i];
+    if (Context->getLangOpts().MicrosoftExt)
+      Result += "__declspec(allocate(\".objc_ivar$B\")) ";
+    
+    if (!Context->getLangOpts().MicrosoftExt ||
+        IvarDecl->getAccessControl() == ObjCIvarDecl::Private ||
+        IvarDecl->getAccessControl() == ObjCIvarDecl::Package)
+      Result += "extern \"C\" unsigned long int "; 
+    else
+      Result += "extern \"C\" __declspec(dllexport) unsigned long int ";
+    if (Ivars[i]->isBitField())
+      RewriteObj.ObjCIvarBitfieldGroupOffset(IvarDecl, Result);
+    else
+      WriteInternalIvarName(CDecl, IvarDecl, Result);
+    Result += " __attribute__ ((used, section (\"__DATA,__objc_ivar\")))";
+    Result += " = ";
+    RewriteObj.RewriteIvarOffsetComputation(IvarDecl, Result);
+    Result += ";\n";
+    if (Ivars[i]->isBitField()) {
+      // skip over rest of the ivar bitfields.
+      SKIP_BITFIELDS(i , e, Ivars);
+    }
+  }
+}
+
+static void Write__ivar_list_t_initializer(RewriteModernObjC &RewriteObj,
+                                           ASTContext *Context, std::string &Result,
+                                           ArrayRef<ObjCIvarDecl *> OriginalIvars,
+                                           StringRef VarName,
+                                           ObjCInterfaceDecl *CDecl) {
+  if (OriginalIvars.size() > 0) {
+    Write_IvarOffsetVar(RewriteObj, Context, Result, OriginalIvars, CDecl);
+    SmallVector<ObjCIvarDecl *, 8> Ivars;
+    // strip off all but the first ivar bitfield from each group of ivars.
+    // Such ivars in the ivar list table will be replaced by their grouping struct
+    // 'ivar'.
+    for (unsigned i = 0, e = OriginalIvars.size(); i < e; i++) {
+      if (OriginalIvars[i]->isBitField()) {
+        Ivars.push_back(OriginalIvars[i]);
+        // skip over rest of the ivar bitfields.
+        SKIP_BITFIELDS(i , e, OriginalIvars);
+      }
+      else
+        Ivars.push_back(OriginalIvars[i]);
+    }
+    
+    Result += "\nstatic ";
+    Write__ivar_list_t_TypeDecl(Result, Ivars.size());
+    Result += " "; Result += VarName;
+    Result += CDecl->getNameAsString();
+    Result += " __attribute__ ((used, section (\"__DATA,__objc_const\"))) = {\n";
+    Result += "\t"; Result += "sizeof(_ivar_t)"; Result += ",\n";
+    Result += "\t"; Result += utostr(Ivars.size()); Result += ",\n";
+    for (unsigned i =0, e = Ivars.size(); i < e; i++) {
+      ObjCIvarDecl *IvarDecl = Ivars[i];
+      if (i == 0)
+        Result += "\t{{";
+      else
+        Result += "\t {";
+      Result += "(unsigned long int *)&";
+      if (Ivars[i]->isBitField())
+        RewriteObj.ObjCIvarBitfieldGroupOffset(IvarDecl, Result);
+      else
+        WriteInternalIvarName(CDecl, IvarDecl, Result);
+      Result += ", ";
+      
+      Result += "\"";
+      if (Ivars[i]->isBitField())
+        RewriteObj.ObjCIvarBitfieldGroupDecl(Ivars[i], Result);
+      else
+        Result += IvarDecl->getName();
+      Result += "\", ";
+      
+      QualType IVQT = IvarDecl->getType();
+      if (IvarDecl->isBitField())
+        IVQT = RewriteObj.GetGroupRecordTypeForObjCIvarBitfield(IvarDecl);
+      
+      std::string IvarTypeString, QuoteIvarTypeString;
+      Context->getObjCEncodingForType(IVQT, IvarTypeString,
+                                      IvarDecl);
+      RewriteObj.QuoteDoublequotes(IvarTypeString, QuoteIvarTypeString);
+      Result += "\""; Result += QuoteIvarTypeString; Result += "\", ";
+      
+      // FIXME. this alignment represents the host alignment and need be changed to
+      // represent the target alignment.
+      unsigned Align = Context->getTypeAlign(IVQT)/8;
+      Align = llvm::Log2_32(Align);
+      Result += llvm::utostr(Align); Result += ", ";
+      CharUnits Size = Context->getTypeSizeInChars(IVQT);
+      Result += llvm::utostr(Size.getQuantity());
+      if (i  == e-1)
+        Result += "}}\n";
+      else
+        Result += "},\n";
+    }
+    Result += "};\n";
+  }
+}
+
+/// RewriteObjCProtocolMetaData - Rewrite protocols meta-data.
+void RewriteModernObjC::RewriteObjCProtocolMetaData(ObjCProtocolDecl *PDecl, 
+                                                    std::string &Result) {
+  
+  // Do not synthesize the protocol more than once.
+  if (ObjCSynthesizedProtocols.count(PDecl->getCanonicalDecl()))
+    return;
+  WriteModernMetadataDeclarations(Context, Result);
+  
+  if (ObjCProtocolDecl *Def = PDecl->getDefinition())
+    PDecl = Def;
+  // Must write out all protocol definitions in current qualifier list,
+  // and in their nested qualifiers before writing out current definition.
+  for (auto *I : PDecl->protocols())
+    RewriteObjCProtocolMetaData(I, Result);
+  
+  // Construct method lists.
+  std::vector<ObjCMethodDecl *> InstanceMethods, ClassMethods;
+  std::vector<ObjCMethodDecl *> OptInstanceMethods, OptClassMethods;
+  for (auto *MD : PDecl->instance_methods()) {
+    if (MD->getImplementationControl() == ObjCMethodDecl::Optional) {
+      OptInstanceMethods.push_back(MD);
+    } else {
+      InstanceMethods.push_back(MD);
+    }
+  }
+  
+  for (auto *MD : PDecl->class_methods()) {
+    if (MD->getImplementationControl() == ObjCMethodDecl::Optional) {
+      OptClassMethods.push_back(MD);
+    } else {
+      ClassMethods.push_back(MD);
+    }
+  }
+  std::vector<ObjCMethodDecl *> AllMethods;
+  for (unsigned i = 0, e = InstanceMethods.size(); i < e; i++)
+    AllMethods.push_back(InstanceMethods[i]);
+  for (unsigned i = 0, e = ClassMethods.size(); i < e; i++)
+    AllMethods.push_back(ClassMethods[i]);
+  for (unsigned i = 0, e = OptInstanceMethods.size(); i < e; i++)
+    AllMethods.push_back(OptInstanceMethods[i]);
+  for (unsigned i = 0, e = OptClassMethods.size(); i < e; i++)
+    AllMethods.push_back(OptClassMethods[i]);
+
+  Write__extendedMethodTypes_initializer(*this, Context, Result,
+                                         AllMethods,
+                                         "_OBJC_PROTOCOL_METHOD_TYPES_",
+                                         PDecl->getNameAsString());
+  // Protocol's super protocol list
+  SmallVector<ObjCProtocolDecl *, 8> SuperProtocols(PDecl->protocols());  
+  Write_protocol_list_initializer(Context, Result, SuperProtocols,
+                                  "_OBJC_PROTOCOL_REFS_",
+                                  PDecl->getNameAsString());
+  
+  Write_method_list_t_initializer(*this, Context, Result, InstanceMethods, 
+                                  "_OBJC_PROTOCOL_INSTANCE_METHODS_",
+                                  PDecl->getNameAsString(), false);
+  
+  Write_method_list_t_initializer(*this, Context, Result, ClassMethods, 
+                                  "_OBJC_PROTOCOL_CLASS_METHODS_",
+                                  PDecl->getNameAsString(), false);
+
+  Write_method_list_t_initializer(*this, Context, Result, OptInstanceMethods, 
+                                  "_OBJC_PROTOCOL_OPT_INSTANCE_METHODS_",
+                                  PDecl->getNameAsString(), false);
+  
+  Write_method_list_t_initializer(*this, Context, Result, OptClassMethods, 
+                                  "_OBJC_PROTOCOL_OPT_CLASS_METHODS_",
+                                  PDecl->getNameAsString(), false);
+  
+  // Protocol's property metadata.
+  SmallVector<ObjCPropertyDecl *, 8> ProtocolProperties(PDecl->properties());
+  Write_prop_list_t_initializer(*this, Context, Result, ProtocolProperties,
+                                 /* Container */nullptr,
+                                 "_OBJC_PROTOCOL_PROPERTIES_",
+                                 PDecl->getNameAsString());
+
+  // Writer out root metadata for current protocol: struct _protocol_t
+  Result += "\n";
+  if (LangOpts.MicrosoftExt)
+    Result += "static ";
+  Result += "struct _protocol_t _OBJC_PROTOCOL_";
+  Result += PDecl->getNameAsString();
+  Result += " __attribute__ ((used, section (\"__DATA,__datacoal_nt,coalesced\"))) = {\n";
+  Result += "\t0,\n"; // id is; is null
+  Result += "\t\""; Result += PDecl->getNameAsString(); Result += "\",\n";
+  if (SuperProtocols.size() > 0) {
+    Result += "\t(const struct _protocol_list_t *)&"; Result += "_OBJC_PROTOCOL_REFS_";
+    Result += PDecl->getNameAsString(); Result += ",\n";
+  }
+  else
+    Result += "\t0,\n";
+  if (InstanceMethods.size() > 0) {
+    Result += "\t(const struct method_list_t *)&_OBJC_PROTOCOL_INSTANCE_METHODS_"; 
+    Result += PDecl->getNameAsString(); Result += ",\n";
+  }
+  else
+    Result += "\t0,\n";
+
+  if (ClassMethods.size() > 0) {
+    Result += "\t(const struct method_list_t *)&_OBJC_PROTOCOL_CLASS_METHODS_"; 
+    Result += PDecl->getNameAsString(); Result += ",\n";
+  }
+  else
+    Result += "\t0,\n";
+  
+  if (OptInstanceMethods.size() > 0) {
+    Result += "\t(const struct method_list_t *)&_OBJC_PROTOCOL_OPT_INSTANCE_METHODS_"; 
+    Result += PDecl->getNameAsString(); Result += ",\n";
+  }
+  else
+    Result += "\t0,\n";
+  
+  if (OptClassMethods.size() > 0) {
+    Result += "\t(const struct method_list_t *)&_OBJC_PROTOCOL_OPT_CLASS_METHODS_"; 
+    Result += PDecl->getNameAsString(); Result += ",\n";
+  }
+  else
+    Result += "\t0,\n";
+  
+  if (ProtocolProperties.size() > 0) {
+    Result += "\t(const struct _prop_list_t *)&_OBJC_PROTOCOL_PROPERTIES_"; 
+    Result += PDecl->getNameAsString(); Result += ",\n";
+  }
+  else
+    Result += "\t0,\n";
+  
+  Result += "\t"; Result += "sizeof(_protocol_t)"; Result += ",\n";
+  Result += "\t0,\n";
+  
+  if (AllMethods.size() > 0) {
+    Result += "\t(const char **)&"; Result += "_OBJC_PROTOCOL_METHOD_TYPES_";
+    Result += PDecl->getNameAsString();
+    Result += "\n};\n";
+  }
+  else
+    Result += "\t0\n};\n";
+  
+  if (LangOpts.MicrosoftExt)
+    Result += "static ";
+  Result += "struct _protocol_t *";
+  Result += "_OBJC_LABEL_PROTOCOL_$_"; Result += PDecl->getNameAsString();
+  Result += " = &_OBJC_PROTOCOL_"; Result += PDecl->getNameAsString();
+  Result += ";\n";
+    
+  // Mark this protocol as having been generated.
+  if (!ObjCSynthesizedProtocols.insert(PDecl->getCanonicalDecl()))
+    llvm_unreachable("protocol already synthesized");
+  
+}
+
+void RewriteModernObjC::RewriteObjCProtocolListMetaData(
+                                const ObjCList<ObjCProtocolDecl> &Protocols,
+                                StringRef prefix, StringRef ClassName,
+                                std::string &Result) {
+  if (Protocols.empty()) return;
+  
+  for (unsigned i = 0; i != Protocols.size(); i++)
+    RewriteObjCProtocolMetaData(Protocols[i], Result);
+  
+  // Output the top lovel protocol meta-data for the class.
+  /* struct _objc_protocol_list {
+   struct _objc_protocol_list *next;
+   int    protocol_count;
+   struct _objc_protocol *class_protocols[];
+   }
+   */
+  Result += "\n";
+  if (LangOpts.MicrosoftExt)
+    Result += "__declspec(allocate(\".cat_cls_meth$B\")) ";
+  Result += "static struct {\n";
+  Result += "\tstruct _objc_protocol_list *next;\n";
+  Result += "\tint    protocol_count;\n";
+  Result += "\tstruct _objc_protocol *class_protocols[";
+  Result += utostr(Protocols.size());
+  Result += "];\n} _OBJC_";
+  Result += prefix;
+  Result += "_PROTOCOLS_";
+  Result += ClassName;
+  Result += " __attribute__ ((used, section (\"__OBJC, __cat_cls_meth\")))= "
+  "{\n\t0, ";
+  Result += utostr(Protocols.size());
+  Result += "\n";
+  
+  Result += "\t,{&_OBJC_PROTOCOL_";
+  Result += Protocols[0]->getNameAsString();
+  Result += " \n";
+  
+  for (unsigned i = 1; i != Protocols.size(); i++) {
+    Result += "\t ,&_OBJC_PROTOCOL_";
+    Result += Protocols[i]->getNameAsString();
+    Result += "\n";
+  }
+  Result += "\t }\n};\n";
+}
+
+/// hasObjCExceptionAttribute - Return true if this class or any super
+/// class has the __objc_exception__ attribute.
+/// FIXME. Move this to ASTContext.cpp as it is also used for IRGen.
+static bool hasObjCExceptionAttribute(ASTContext &Context,
+                                      const ObjCInterfaceDecl *OID) {
+  if (OID->hasAttr<ObjCExceptionAttr>())
+    return true;
+  if (const ObjCInterfaceDecl *Super = OID->getSuperClass())
+    return hasObjCExceptionAttribute(Context, Super);
+  return false;
+}
+
+void RewriteModernObjC::RewriteObjCClassMetaData(ObjCImplementationDecl *IDecl,
+                                           std::string &Result) {
+  ObjCInterfaceDecl *CDecl = IDecl->getClassInterface();
+  
+  // Explicitly declared @interface's are already synthesized.
+  if (CDecl->isImplicitInterfaceDecl())
+    assert(false && 
+           "Legacy implicit interface rewriting not supported in moder abi");
+  
+  WriteModernMetadataDeclarations(Context, Result);
+  SmallVector<ObjCIvarDecl *, 8> IVars;
+  
+  for (ObjCIvarDecl *IVD = CDecl->all_declared_ivar_begin();
+      IVD; IVD = IVD->getNextIvar()) {
+    // Ignore unnamed bit-fields.
+    if (!IVD->getDeclName())
+      continue;
+    IVars.push_back(IVD);
+  }
+  
+  Write__ivar_list_t_initializer(*this, Context, Result, IVars, 
+                                 "_OBJC_$_INSTANCE_VARIABLES_",
+                                 CDecl);
+  
+  // Build _objc_method_list for class's instance methods if needed
+  SmallVector<ObjCMethodDecl *, 32> InstanceMethods(IDecl->instance_methods());
+  
+  // If any of our property implementations have associated getters or
+  // setters, produce metadata for them as well.
+  for (const auto *Prop : IDecl->property_impls()) {
+    if (Prop->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic)
+      continue;
+    if (!Prop->getPropertyIvarDecl())
+      continue;
+    ObjCPropertyDecl *PD = Prop->getPropertyDecl();
+    if (!PD)
+      continue;
+    if (ObjCMethodDecl *Getter = PD->getGetterMethodDecl())
+      if (mustSynthesizeSetterGetterMethod(IDecl, PD, true /*getter*/))
+        InstanceMethods.push_back(Getter);
+    if (PD->isReadOnly())
+      continue;
+    if (ObjCMethodDecl *Setter = PD->getSetterMethodDecl())
+      if (mustSynthesizeSetterGetterMethod(IDecl, PD, false /*setter*/))
+        InstanceMethods.push_back(Setter);
+  }
+  
+  Write_method_list_t_initializer(*this, Context, Result, InstanceMethods,
+                                  "_OBJC_$_INSTANCE_METHODS_",
+                                  IDecl->getNameAsString(), true);
+  
+  SmallVector<ObjCMethodDecl *, 32> ClassMethods(IDecl->class_methods());
+  
+  Write_method_list_t_initializer(*this, Context, Result, ClassMethods,
+                                  "_OBJC_$_CLASS_METHODS_",
+                                  IDecl->getNameAsString(), true);
+  
+  // Protocols referenced in class declaration?
+  // Protocol's super protocol list
+  std::vector<ObjCProtocolDecl *> RefedProtocols;
+  const ObjCList<ObjCProtocolDecl> &Protocols = CDecl->getReferencedProtocols();
+  for (ObjCList<ObjCProtocolDecl>::iterator I = Protocols.begin(),
+       E = Protocols.end();
+       I != E; ++I) {
+    RefedProtocols.push_back(*I);
+    // Must write out all protocol definitions in current qualifier list,
+    // and in their nested qualifiers before writing out current definition.
+    RewriteObjCProtocolMetaData(*I, Result);
+  }
+  
+  Write_protocol_list_initializer(Context, Result, 
+                                  RefedProtocols,
+                                  "_OBJC_CLASS_PROTOCOLS_$_",
+                                  IDecl->getNameAsString());
+  
+  // Protocol's property metadata.
+  SmallVector<ObjCPropertyDecl *, 8> ClassProperties(CDecl->properties());
+  Write_prop_list_t_initializer(*this, Context, Result, ClassProperties,
+                                 /* Container */IDecl,
+                                 "_OBJC_$_PROP_LIST_",
+                                 CDecl->getNameAsString());
+
+  
+  // Data for initializing _class_ro_t  metaclass meta-data
+  uint32_t flags = CLS_META;
+  std::string InstanceSize;
+  std::string InstanceStart;
+  
+  
+  bool classIsHidden = CDecl->getVisibility() == HiddenVisibility;
+  if (classIsHidden)
+    flags |= OBJC2_CLS_HIDDEN;
+  
+  if (!CDecl->getSuperClass())
+    // class is root
+    flags |= CLS_ROOT;
+  InstanceSize = "sizeof(struct _class_t)";
+  InstanceStart = InstanceSize;
+  Write__class_ro_t_initializer(Context, Result, flags, 
+                                InstanceStart, InstanceSize,
+                                ClassMethods,
+                                nullptr,
+                                nullptr,
+                                nullptr,
+                                "_OBJC_METACLASS_RO_$_",
+                                CDecl->getNameAsString());
+
+  // Data for initializing _class_ro_t meta-data
+  flags = CLS;
+  if (classIsHidden)
+    flags |= OBJC2_CLS_HIDDEN;
+  
+  if (hasObjCExceptionAttribute(*Context, CDecl))
+    flags |= CLS_EXCEPTION;
+
+  if (!CDecl->getSuperClass())
+    // class is root
+    flags |= CLS_ROOT;
+  
+  InstanceSize.clear();
+  InstanceStart.clear();
+  if (!ObjCSynthesizedStructs.count(CDecl)) {
+    InstanceSize = "0";
+    InstanceStart = "0";
+  }
+  else {
+    InstanceSize = "sizeof(struct ";
+    InstanceSize += CDecl->getNameAsString();
+    InstanceSize += "_IMPL)";
+    
+    ObjCIvarDecl *IVD = CDecl->all_declared_ivar_begin();
+    if (IVD) {
+      RewriteIvarOffsetComputation(IVD, InstanceStart);
+    }
+    else 
+      InstanceStart = InstanceSize;
+  }
+  Write__class_ro_t_initializer(Context, Result, flags, 
+                                InstanceStart, InstanceSize,
+                                InstanceMethods,
+                                RefedProtocols,
+                                IVars,
+                                ClassProperties,
+                                "_OBJC_CLASS_RO_$_",
+                                CDecl->getNameAsString());
+  
+  Write_class_t(Context, Result,
+                "OBJC_METACLASS_$_",
+                CDecl, /*metaclass*/true);
+  
+  Write_class_t(Context, Result,
+                "OBJC_CLASS_$_",
+                CDecl, /*metaclass*/false);
+  
+  if (ImplementationIsNonLazy(IDecl))
+    DefinedNonLazyClasses.push_back(CDecl);
+                
+}
+
+void RewriteModernObjC::RewriteClassSetupInitHook(std::string &Result) {
+  int ClsDefCount = ClassImplementation.size();
+  if (!ClsDefCount)
+    return;
+  Result += "#pragma section(\".objc_inithooks$B\", long, read, write)\n";
+  Result += "__declspec(allocate(\".objc_inithooks$B\")) ";
+  Result += "static void *OBJC_CLASS_SETUP[] = {\n";
+  for (int i = 0; i < ClsDefCount; i++) {
+    ObjCImplementationDecl *IDecl = ClassImplementation[i];
+    ObjCInterfaceDecl *CDecl = IDecl->getClassInterface();
+    Result += "\t(void *)&OBJC_CLASS_SETUP_$_";
+    Result  += CDecl->getName(); Result += ",\n";
+  }
+  Result += "};\n";
+}
+
+void RewriteModernObjC::RewriteMetaDataIntoBuffer(std::string &Result) {
+  int ClsDefCount = ClassImplementation.size();
+  int CatDefCount = CategoryImplementation.size();
+  
+  // For each implemented class, write out all its meta data.
+  for (int i = 0; i < ClsDefCount; i++)
+    RewriteObjCClassMetaData(ClassImplementation[i], Result);
+  
+  RewriteClassSetupInitHook(Result);
+  
+  // For each implemented category, write out all its meta data.
+  for (int i = 0; i < CatDefCount; i++)
+    RewriteObjCCategoryImplDecl(CategoryImplementation[i], Result);
+  
+  RewriteCategorySetupInitHook(Result);
+  
+  if (ClsDefCount > 0) {
+    if (LangOpts.MicrosoftExt)
+      Result += "__declspec(allocate(\".objc_classlist$B\")) ";
+    Result += "static struct _class_t *L_OBJC_LABEL_CLASS_$ [";
+    Result += llvm::utostr(ClsDefCount); Result += "]";
+    Result += 
+      " __attribute__((used, section (\"__DATA, __objc_classlist,"
+      "regular,no_dead_strip\")))= {\n";
+    for (int i = 0; i < ClsDefCount; i++) {
+      Result += "\t&OBJC_CLASS_$_";
+      Result += ClassImplementation[i]->getNameAsString();
+      Result += ",\n";
+    }
+    Result += "};\n";
+    
+    if (!DefinedNonLazyClasses.empty()) {
+      if (LangOpts.MicrosoftExt)
+        Result += "__declspec(allocate(\".objc_nlclslist$B\")) \n";
+      Result += "static struct _class_t *_OBJC_LABEL_NONLAZY_CLASS_$[] = {\n\t";
+      for (unsigned i = 0, e = DefinedNonLazyClasses.size(); i < e; i++) {
+        Result += "\t&OBJC_CLASS_$_"; Result += DefinedNonLazyClasses[i]->getNameAsString();
+        Result += ",\n";
+      }
+      Result += "};\n";
+    }
+  }
+  
+  if (CatDefCount > 0) {
+    if (LangOpts.MicrosoftExt)
+      Result += "__declspec(allocate(\".objc_catlist$B\")) ";
+    Result += "static struct _category_t *L_OBJC_LABEL_CATEGORY_$ [";
+    Result += llvm::utostr(CatDefCount); Result += "]";
+    Result += 
+    " __attribute__((used, section (\"__DATA, __objc_catlist,"
+    "regular,no_dead_strip\")))= {\n";
+    for (int i = 0; i < CatDefCount; i++) {
+      Result += "\t&_OBJC_$_CATEGORY_";
+      Result += 
+        CategoryImplementation[i]->getClassInterface()->getNameAsString(); 
+      Result += "_$_";
+      Result += CategoryImplementation[i]->getNameAsString();
+      Result += ",\n";
+    }
+    Result += "};\n";
+  }
+  
+  if (!DefinedNonLazyCategories.empty()) {
+    if (LangOpts.MicrosoftExt)
+      Result += "__declspec(allocate(\".objc_nlcatlist$B\")) \n";
+    Result += "static struct _category_t *_OBJC_LABEL_NONLAZY_CATEGORY_$[] = {\n\t";
+    for (unsigned i = 0, e = DefinedNonLazyCategories.size(); i < e; i++) {
+      Result += "\t&_OBJC_$_CATEGORY_";
+      Result += 
+        DefinedNonLazyCategories[i]->getClassInterface()->getNameAsString(); 
+      Result += "_$_";
+      Result += DefinedNonLazyCategories[i]->getNameAsString();
+      Result += ",\n";
+    }
+    Result += "};\n";
+  }
+}
+
+void RewriteModernObjC::WriteImageInfo(std::string &Result) {
+  if (LangOpts.MicrosoftExt)
+    Result += "__declspec(allocate(\".objc_imageinfo$B\")) \n";
+  
+  Result += "static struct IMAGE_INFO { unsigned version; unsigned flag; } ";
+  // version 0, ObjCABI is 2
+  Result += "_OBJC_IMAGE_INFO = { 0, 2 };\n";
+}
+
+/// RewriteObjCCategoryImplDecl - Rewrite metadata for each category
+/// implementation.
+void RewriteModernObjC::RewriteObjCCategoryImplDecl(ObjCCategoryImplDecl *IDecl,
+                                              std::string &Result) {
+  WriteModernMetadataDeclarations(Context, Result);
+  ObjCInterfaceDecl *ClassDecl = IDecl->getClassInterface();
+  // Find category declaration for this implementation.
+  ObjCCategoryDecl *CDecl
+    = ClassDecl->FindCategoryDeclaration(IDecl->getIdentifier());
+  
+  std::string FullCategoryName = ClassDecl->getNameAsString();
+  FullCategoryName += "_$_";
+  FullCategoryName += CDecl->getNameAsString();
+  
+  // Build _objc_method_list for class's instance methods if needed
+  SmallVector<ObjCMethodDecl *, 32> InstanceMethods(IDecl->instance_methods());
+  
+  // If any of our property implementations have associated getters or
+  // setters, produce metadata for them as well.
+  for (const auto *Prop : IDecl->property_impls()) {
+    if (Prop->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic)
+      continue;
+    if (!Prop->getPropertyIvarDecl())
+      continue;
+    ObjCPropertyDecl *PD = Prop->getPropertyDecl();
+    if (!PD)
+      continue;
+    if (ObjCMethodDecl *Getter = PD->getGetterMethodDecl())
+      InstanceMethods.push_back(Getter);
+    if (PD->isReadOnly())
+      continue;
+    if (ObjCMethodDecl *Setter = PD->getSetterMethodDecl())
+      InstanceMethods.push_back(Setter);
+  }
+  
+  Write_method_list_t_initializer(*this, Context, Result, InstanceMethods,
+                                  "_OBJC_$_CATEGORY_INSTANCE_METHODS_",
+                                  FullCategoryName, true);
+  
+  SmallVector<ObjCMethodDecl *, 32> ClassMethods(IDecl->class_methods());
+  
+  Write_method_list_t_initializer(*this, Context, Result, ClassMethods,
+                                  "_OBJC_$_CATEGORY_CLASS_METHODS_",
+                                  FullCategoryName, true);
+  
+  // Protocols referenced in class declaration?
+  // Protocol's super protocol list
+  SmallVector<ObjCProtocolDecl *, 8> RefedProtocols(CDecl->protocols());
+  for (auto *I : CDecl->protocols())
+    // Must write out all protocol definitions in current qualifier list,
+    // and in their nested qualifiers before writing out current definition.
+    RewriteObjCProtocolMetaData(I, Result);
+  
+  Write_protocol_list_initializer(Context, Result, 
+                                  RefedProtocols,
+                                  "_OBJC_CATEGORY_PROTOCOLS_$_",
+                                  FullCategoryName);
+  
+  // Protocol's property metadata.
+  SmallVector<ObjCPropertyDecl *, 8> ClassProperties(CDecl->properties());
+  Write_prop_list_t_initializer(*this, Context, Result, ClassProperties,
+                                /* Container */IDecl,
+                                "_OBJC_$_PROP_LIST_",
+                                FullCategoryName);
+  
+  Write_category_t(*this, Context, Result,
+                   CDecl,
+                   ClassDecl,
+                   InstanceMethods,
+                   ClassMethods,
+                   RefedProtocols,
+                   ClassProperties);
+  
+  // Determine if this category is also "non-lazy".
+  if (ImplementationIsNonLazy(IDecl))
+    DefinedNonLazyCategories.push_back(CDecl);
+    
+}
+
+void RewriteModernObjC::RewriteCategorySetupInitHook(std::string &Result) {
+  int CatDefCount = CategoryImplementation.size();
+  if (!CatDefCount)
+    return;
+  Result += "#pragma section(\".objc_inithooks$B\", long, read, write)\n";
+  Result += "__declspec(allocate(\".objc_inithooks$B\")) ";
+  Result += "static void *OBJC_CATEGORY_SETUP[] = {\n";
+  for (int i = 0; i < CatDefCount; i++) {
+    ObjCCategoryImplDecl *IDecl = CategoryImplementation[i];
+    ObjCCategoryDecl *CatDecl= IDecl->getCategoryDecl();
+    ObjCInterfaceDecl *ClassDecl = IDecl->getClassInterface();
+    Result += "\t(void *)&OBJC_CATEGORY_SETUP_$_";
+    Result += ClassDecl->getName();
+    Result += "_$_";
+    Result += CatDecl->getName();
+    Result += ",\n";
+  }
+  Result += "};\n";
+}
+
+// RewriteObjCMethodsMetaData - Rewrite methods metadata for instance or
+/// class methods.
+template<typename MethodIterator>
+void RewriteModernObjC::RewriteObjCMethodsMetaData(MethodIterator MethodBegin,
+                                             MethodIterator MethodEnd,
+                                             bool IsInstanceMethod,
+                                             StringRef prefix,
+                                             StringRef ClassName,
+                                             std::string &Result) {
+  if (MethodBegin == MethodEnd) return;
+  
+  if (!objc_impl_method) {
+    /* struct _objc_method {
+     SEL _cmd;
+     char *method_types;
+     void *_imp;
+     }
+     */
+    Result += "\nstruct _objc_method {\n";
+    Result += "\tSEL _cmd;\n";
+    Result += "\tchar *method_types;\n";
+    Result += "\tvoid *_imp;\n";
+    Result += "};\n";
+    
+    objc_impl_method = true;
+  }
+  
+  // Build _objc_method_list for class's methods if needed
+  
+  /* struct  {
+   struct _objc_method_list *next_method;
+   int method_count;
+   struct _objc_method method_list[];
+   }
+   */
+  unsigned NumMethods = std::distance(MethodBegin, MethodEnd);
+  Result += "\n";
+  if (LangOpts.MicrosoftExt) {
+    if (IsInstanceMethod)
+      Result += "__declspec(allocate(\".inst_meth$B\")) ";
+    else
+      Result += "__declspec(allocate(\".cls_meth$B\")) ";
+  }
+  Result += "static struct {\n";
+  Result += "\tstruct _objc_method_list *next_method;\n";
+  Result += "\tint method_count;\n";
+  Result += "\tstruct _objc_method method_list[";
+  Result += utostr(NumMethods);
+  Result += "];\n} _OBJC_";
+  Result += prefix;
+  Result += IsInstanceMethod ? "INSTANCE" : "CLASS";
+  Result += "_METHODS_";
+  Result += ClassName;
+  Result += " __attribute__ ((used, section (\"__OBJC, __";
+  Result += IsInstanceMethod ? "inst" : "cls";
+  Result += "_meth\")))= ";
+  Result += "{\n\t0, " + utostr(NumMethods) + "\n";
+  
+  Result += "\t,{{(SEL)\"";
+  Result += (*MethodBegin)->getSelector().getAsString().c_str();
+  std::string MethodTypeString;
+  Context->getObjCEncodingForMethodDecl(*MethodBegin, MethodTypeString);
+  Result += "\", \"";
+  Result += MethodTypeString;
+  Result += "\", (void *)";
+  Result += MethodInternalNames[*MethodBegin];
+  Result += "}\n";
+  for (++MethodBegin; MethodBegin != MethodEnd; ++MethodBegin) {
+    Result += "\t  ,{(SEL)\"";
+    Result += (*MethodBegin)->getSelector().getAsString().c_str();
+    std::string MethodTypeString;
+    Context->getObjCEncodingForMethodDecl(*MethodBegin, MethodTypeString);
+    Result += "\", \"";
+    Result += MethodTypeString;
+    Result += "\", (void *)";
+    Result += MethodInternalNames[*MethodBegin];
+    Result += "}\n";
+  }
+  Result += "\t }\n};\n";
+}
+
+Stmt *RewriteModernObjC::RewriteObjCIvarRefExpr(ObjCIvarRefExpr *IV) {
+  SourceRange OldRange = IV->getSourceRange();
+  Expr *BaseExpr = IV->getBase();
+  
+  // Rewrite the base, but without actually doing replaces.
+  {
+    DisableReplaceStmtScope S(*this);
+    BaseExpr = cast<Expr>(RewriteFunctionBodyOrGlobalInitializer(BaseExpr));
+    IV->setBase(BaseExpr);
+  }
+  
+  ObjCIvarDecl *D = IV->getDecl();
+  
+  Expr *Replacement = IV;
+  
+    if (BaseExpr->getType()->isObjCObjectPointerType()) {
+      const ObjCInterfaceType *iFaceDecl =
+        dyn_cast<ObjCInterfaceType>(BaseExpr->getType()->getPointeeType());
+      assert(iFaceDecl && "RewriteObjCIvarRefExpr - iFaceDecl is null");
+      // lookup which class implements the instance variable.
+      ObjCInterfaceDecl *clsDeclared = nullptr;
+      iFaceDecl->getDecl()->lookupInstanceVariable(D->getIdentifier(),
+                                                   clsDeclared);
+      assert(clsDeclared && "RewriteObjCIvarRefExpr(): Can't find class");
+      
+      // Build name of symbol holding ivar offset.
+      std::string IvarOffsetName;
+      if (D->isBitField())
+        ObjCIvarBitfieldGroupOffset(D, IvarOffsetName);
+      else
+        WriteInternalIvarName(clsDeclared, D, IvarOffsetName);
+      
+      ReferencedIvars[clsDeclared].insert(D);
+      
+      // cast offset to "char *".
+      CastExpr *castExpr = NoTypeInfoCStyleCastExpr(Context, 
+                                                    Context->getPointerType(Context->CharTy),
+                                                    CK_BitCast,
+                                                    BaseExpr);
+      VarDecl *NewVD = VarDecl::Create(*Context, TUDecl, SourceLocation(),
+                                       SourceLocation(), &Context->Idents.get(IvarOffsetName),
+                                       Context->UnsignedLongTy, nullptr,
+                                       SC_Extern);
+      DeclRefExpr *DRE = new (Context) DeclRefExpr(NewVD, false,
+                                                   Context->UnsignedLongTy, VK_LValue,
+                                                   SourceLocation());
+      BinaryOperator *addExpr = 
+        new (Context) BinaryOperator(castExpr, DRE, BO_Add, 
+                                     Context->getPointerType(Context->CharTy),
+                                     VK_RValue, OK_Ordinary, SourceLocation(), false);
+      // Don't forget the parens to enforce the proper binding.
+      ParenExpr *PE = new (Context) ParenExpr(SourceLocation(),
+                                              SourceLocation(),
+                                              addExpr);
+      QualType IvarT = D->getType();
+      if (D->isBitField())
+        IvarT = GetGroupRecordTypeForObjCIvarBitfield(D);
+
+      if (!isa<TypedefType>(IvarT) && IvarT->isRecordType()) {
+        RecordDecl *RD = IvarT->getAs<RecordType>()->getDecl();
+        RD = RD->getDefinition();
+        if (RD && !RD->getDeclName().getAsIdentifierInfo()) {
+          // decltype(((Foo_IMPL*)0)->bar) *
+          ObjCContainerDecl *CDecl = 
+            dyn_cast<ObjCContainerDecl>(D->getDeclContext());
+          // ivar in class extensions requires special treatment.
+          if (ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CDecl))
+            CDecl = CatDecl->getClassInterface();
+          std::string RecName = CDecl->getName();
+          RecName += "_IMPL";
+          RecordDecl *RD = RecordDecl::Create(*Context, TTK_Struct, TUDecl,
+                                              SourceLocation(), SourceLocation(),
+                                              &Context->Idents.get(RecName.c_str()));
+          QualType PtrStructIMPL = Context->getPointerType(Context->getTagDeclType(RD));
+          unsigned UnsignedIntSize = 
+            static_cast<unsigned>(Context->getTypeSize(Context->UnsignedIntTy));
+          Expr *Zero = IntegerLiteral::Create(*Context,
+                                              llvm::APInt(UnsignedIntSize, 0),
+                                              Context->UnsignedIntTy, SourceLocation());
+          Zero = NoTypeInfoCStyleCastExpr(Context, PtrStructIMPL, CK_BitCast, Zero);
+          ParenExpr *PE = new (Context) ParenExpr(SourceLocation(), SourceLocation(),
+                                                  Zero);
+          FieldDecl *FD = FieldDecl::Create(*Context, nullptr, SourceLocation(),
+                                            SourceLocation(),
+                                            &Context->Idents.get(D->getNameAsString()),
+                                            IvarT, nullptr,
+                                            /*BitWidth=*/nullptr,
+                                            /*Mutable=*/true, ICIS_NoInit);
+          MemberExpr *ME = new (Context) MemberExpr(PE, true, FD, SourceLocation(),
+                                                    FD->getType(), VK_LValue,
+                                                    OK_Ordinary);
+          IvarT = Context->getDecltypeType(ME, ME->getType());
+        }
+      }
+      convertObjCTypeToCStyleType(IvarT);
+      QualType castT = Context->getPointerType(IvarT);
+          
+      castExpr = NoTypeInfoCStyleCastExpr(Context, 
+                                          castT,
+                                          CK_BitCast,
+                                          PE);
+      
+      
+      Expr *Exp = new (Context) UnaryOperator(castExpr, UO_Deref, IvarT,
+                                              VK_LValue, OK_Ordinary,
+                                              SourceLocation());
+      PE = new (Context) ParenExpr(OldRange.getBegin(),
+                                   OldRange.getEnd(),
+                                   Exp);
+      
+      if (D->isBitField()) {
+        FieldDecl *FD = FieldDecl::Create(*Context, nullptr, SourceLocation(),
+                                          SourceLocation(),
+                                          &Context->Idents.get(D->getNameAsString()),
+                                          D->getType(), nullptr,
+                                          /*BitWidth=*/D->getBitWidth(),
+                                          /*Mutable=*/true, ICIS_NoInit);
+        MemberExpr *ME = new (Context) MemberExpr(PE, /*isArrow*/false, FD, SourceLocation(),
+                                                  FD->getType(), VK_LValue,
+                                                  OK_Ordinary);
+        Replacement = ME;
+
+      }
+      else
+        Replacement = PE;
+    }
+  
+    ReplaceStmtWithRange(IV, Replacement, OldRange);
+    return Replacement;  
+}
+
+#endif
diff --git a/lib/Frontend/Rewrite/RewriteObjC.cpp b/lib/Frontend/Rewrite/RewriteObjC.cpp
new file mode 100644
index 000000000000..7a721771759a
--- /dev/null
+++ b/lib/Frontend/Rewrite/RewriteObjC.cpp
@@ -0,0 +1,5952 @@
+//===--- RewriteObjC.cpp - Playground for the code rewriter ---------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Hacks and fun related to the code rewriter.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Rewrite/Frontend/ASTConsumers.h"
+#include "clang/AST/AST.h"
+#include "clang/AST/ASTConsumer.h"
+#include "clang/AST/Attr.h"
+#include "clang/AST/ParentMap.h"
+#include "clang/Basic/CharInfo.h"
+#include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/IdentifierTable.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Lex/Lexer.h"
+#include "clang/Rewrite/Core/Rewriter.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/raw_ostream.h"
+#include <memory>
+
+#ifdef CLANG_ENABLE_OBJC_REWRITER
+
+using namespace clang;
+using llvm::utostr;
+
+namespace {
+  class RewriteObjC : public ASTConsumer {
+  protected:
+    
+    enum {
+      BLOCK_FIELD_IS_OBJECT   =  3,  /* id, NSObject, __attribute__((NSObject)),
+                                        block, ... */
+      BLOCK_FIELD_IS_BLOCK    =  7,  /* a block variable */
+      BLOCK_FIELD_IS_BYREF    =  8,  /* the on stack structure holding the 
+                                        __block variable */
+      BLOCK_FIELD_IS_WEAK     = 16,  /* declared __weak, only used in byref copy
+                                        helpers */
+      BLOCK_BYREF_CALLER      = 128, /* called from __block (byref) copy/dispose
+                                        support routines */
+      BLOCK_BYREF_CURRENT_MAX = 256
+    };
+    
+    enum {
+      BLOCK_NEEDS_FREE =        (1 << 24),
+      BLOCK_HAS_COPY_DISPOSE =  (1 << 25),
+      BLOCK_HAS_CXX_OBJ =       (1 << 26),
+      BLOCK_IS_GC =             (1 << 27),
+      BLOCK_IS_GLOBAL =         (1 << 28),
+      BLOCK_HAS_DESCRIPTOR =    (1 << 29)
+    };
+    static const int OBJC_ABI_VERSION = 7;
+    
+    Rewriter Rewrite;
+    DiagnosticsEngine &Diags;
+    const LangOptions &LangOpts;
+    ASTContext *Context;
+    SourceManager *SM;
+    TranslationUnitDecl *TUDecl;
+    FileID MainFileID;
+    const char *MainFileStart, *MainFileEnd;
+    Stmt *CurrentBody;
+    ParentMap *PropParentMap; // created lazily.
+    std::string InFileName;
+    raw_ostream* OutFile;
+    std::string Preamble;
+    
+    TypeDecl *ProtocolTypeDecl;
+    VarDecl *GlobalVarDecl;
+    unsigned RewriteFailedDiag;
+    // ObjC string constant support.
+    unsigned NumObjCStringLiterals;
+    VarDecl *ConstantStringClassReference;
+    RecordDecl *NSStringRecord;
+
+    // ObjC foreach break/continue generation support.
+    int BcLabelCount;
+    
+    unsigned TryFinallyContainsReturnDiag;
+    // Needed for super.
+    ObjCMethodDecl *CurMethodDef;
+    RecordDecl *SuperStructDecl;
+    RecordDecl *ConstantStringDecl;
+    
+    FunctionDecl *MsgSendFunctionDecl;
+    FunctionDecl *MsgSendSuperFunctionDecl;
+    FunctionDecl *MsgSendStretFunctionDecl;
+    FunctionDecl *MsgSendSuperStretFunctionDecl;
+    FunctionDecl *MsgSendFpretFunctionDecl;
+    FunctionDecl *GetClassFunctionDecl;
+    FunctionDecl *GetMetaClassFunctionDecl;
+    FunctionDecl *GetSuperClassFunctionDecl;
+    FunctionDecl *SelGetUidFunctionDecl;
+    FunctionDecl *CFStringFunctionDecl;
+    FunctionDecl *SuperConstructorFunctionDecl;
+    FunctionDecl *CurFunctionDef;
+    FunctionDecl *CurFunctionDeclToDeclareForBlock;
+
+    /* Misc. containers needed for meta-data rewrite. */
+    SmallVector<ObjCImplementationDecl *, 8> ClassImplementation;
+    SmallVector<ObjCCategoryImplDecl *, 8> CategoryImplementation;
+    llvm::SmallPtrSet<ObjCInterfaceDecl*, 8> ObjCSynthesizedStructs;
+    llvm::SmallPtrSet<ObjCProtocolDecl*, 8> ObjCSynthesizedProtocols;
+    llvm::SmallPtrSet<ObjCInterfaceDecl*, 8> ObjCForwardDecls;
+    llvm::DenseMap<ObjCMethodDecl*, std::string> MethodInternalNames;
+    SmallVector<Stmt *, 32> Stmts;
+    SmallVector<int, 8> ObjCBcLabelNo;
+    // Remember all the @protocol(<expr>) expressions.
+    llvm::SmallPtrSet<ObjCProtocolDecl *, 32> ProtocolExprDecls;
+    
+    llvm::DenseSet<uint64_t> CopyDestroyCache;
+
+    // Block expressions.
+    SmallVector<BlockExpr *, 32> Blocks;
+    SmallVector<int, 32> InnerDeclRefsCount;
+    SmallVector<DeclRefExpr *, 32> InnerDeclRefs;
+    
+    SmallVector<DeclRefExpr *, 32> BlockDeclRefs;
+
+    // Block related declarations.
+    SmallVector<ValueDecl *, 8> BlockByCopyDecls;
+    llvm::SmallPtrSet<ValueDecl *, 8> BlockByCopyDeclsPtrSet;
+    SmallVector<ValueDecl *, 8> BlockByRefDecls;
+    llvm::SmallPtrSet<ValueDecl *, 8> BlockByRefDeclsPtrSet;
+    llvm::DenseMap<ValueDecl *, unsigned> BlockByRefDeclNo;
+    llvm::SmallPtrSet<ValueDecl *, 8> ImportedBlockDecls;
+    llvm::SmallPtrSet<VarDecl *, 8> ImportedLocalExternalDecls;
+    
+    llvm::DenseMap<BlockExpr *, std::string> RewrittenBlockExprs;
+
+    // This maps an original source AST to it's rewritten form. This allows
+    // us to avoid rewriting the same node twice (which is very uncommon).
+    // This is needed to support some of the exotic property rewriting.
+    llvm::DenseMap<Stmt *, Stmt *> ReplacedNodes;
+
+    // Needed for header files being rewritten
+    bool IsHeader;
+    bool SilenceRewriteMacroWarning;
+    bool objc_impl_method;
+    
+    bool DisableReplaceStmt;
+    class DisableReplaceStmtScope {
+      RewriteObjC &R;
+      bool SavedValue;
+    
+    public:
+      DisableReplaceStmtScope(RewriteObjC &R)
+        : R(R), SavedValue(R.DisableReplaceStmt) {
+        R.DisableReplaceStmt = true;
+      }
+      ~DisableReplaceStmtScope() {
+        R.DisableReplaceStmt = SavedValue;
+      }
+    };
+    void InitializeCommon(ASTContext &context);
+
+  public:
+
+    // Top Level Driver code.
+    bool HandleTopLevelDecl(DeclGroupRef D) override {
+      for (DeclGroupRef::iterator I = D.begin(), E = D.end(); I != E; ++I) {
+        if (ObjCInterfaceDecl *Class = dyn_cast<ObjCInterfaceDecl>(*I)) {
+          if (!Class->isThisDeclarationADefinition()) {
+            RewriteForwardClassDecl(D);
+            break;
+          }
+        }
+
+        if (ObjCProtocolDecl *Proto = dyn_cast<ObjCProtocolDecl>(*I)) {
+          if (!Proto->isThisDeclarationADefinition()) {
+            RewriteForwardProtocolDecl(D);
+            break;
+          }
+        }
+
+        HandleTopLevelSingleDecl(*I);
+      }
+      return true;
+    }
+    void HandleTopLevelSingleDecl(Decl *D);
+    void HandleDeclInMainFile(Decl *D);
+    RewriteObjC(std::string inFile, raw_ostream *OS,
+                DiagnosticsEngine &D, const LangOptions &LOpts,
+                bool silenceMacroWarn);
+
+    ~RewriteObjC() {}
+
+    void HandleTranslationUnit(ASTContext &C) override;
+
+    void ReplaceStmt(Stmt *Old, Stmt *New) {
+      Stmt *ReplacingStmt = ReplacedNodes[Old];
+
+      if (ReplacingStmt)
+        return; // We can't rewrite the same node twice.
+
+      if (DisableReplaceStmt)
+        return;
+
+      // If replacement succeeded or warning disabled return with no warning.
+      if (!Rewrite.ReplaceStmt(Old, New)) {
+        ReplacedNodes[Old] = New;
+        return;
+      }
+      if (SilenceRewriteMacroWarning)
+        return;
+      Diags.Report(Context->getFullLoc(Old->getLocStart()), RewriteFailedDiag)
+                   << Old->getSourceRange();
+    }
+
+    void ReplaceStmtWithRange(Stmt *Old, Stmt *New, SourceRange SrcRange) {
+      assert(Old != nullptr && New != nullptr && "Expected non-null Stmt's");
+      if (DisableReplaceStmt)
+        return;
+
+      // Measure the old text.
+      int Size = Rewrite.getRangeSize(SrcRange);
+      if (Size == -1) {
+        Diags.Report(Context->getFullLoc(Old->getLocStart()), RewriteFailedDiag)
+                     << Old->getSourceRange();
+        return;
+      }
+      // Get the new text.
+      std::string SStr;
+      llvm::raw_string_ostream S(SStr);
+      New->printPretty(S, nullptr, PrintingPolicy(LangOpts));
+      const std::string &Str = S.str();
+
+      // If replacement succeeded or warning disabled return with no warning.
+      if (!Rewrite.ReplaceText(SrcRange.getBegin(), Size, Str)) {
+        ReplacedNodes[Old] = New;
+        return;
+      }
+      if (SilenceRewriteMacroWarning)
+        return;
+      Diags.Report(Context->getFullLoc(Old->getLocStart()), RewriteFailedDiag)
+                   << Old->getSourceRange();
+    }
+
+    void InsertText(SourceLocation Loc, StringRef Str,
+                    bool InsertAfter = true) {
+      // If insertion succeeded or warning disabled return with no warning.
+      if (!Rewrite.InsertText(Loc, Str, InsertAfter) ||
+          SilenceRewriteMacroWarning)
+        return;
+
+      Diags.Report(Context->getFullLoc(Loc), RewriteFailedDiag);
+    }
+
+    void ReplaceText(SourceLocation Start, unsigned OrigLength,
+                     StringRef Str) {
+      // If removal succeeded or warning disabled return with no warning.
+      if (!Rewrite.ReplaceText(Start, OrigLength, Str) ||
+          SilenceRewriteMacroWarning)
+        return;
+
+      Diags.Report(Context->getFullLoc(Start), RewriteFailedDiag);
+    }
+
+    // Syntactic Rewriting.
+    void RewriteRecordBody(RecordDecl *RD);
+    void RewriteInclude();
+    void RewriteForwardClassDecl(DeclGroupRef D);
+    void RewriteForwardClassDecl(const SmallVectorImpl<Decl *> &DG);
+    void RewriteForwardClassEpilogue(ObjCInterfaceDecl *ClassDecl, 
+                                     const std::string &typedefString);
+    void RewriteImplementations();
+    void RewritePropertyImplDecl(ObjCPropertyImplDecl *PID,
+                                 ObjCImplementationDecl *IMD,
+                                 ObjCCategoryImplDecl *CID);
+    void RewriteInterfaceDecl(ObjCInterfaceDecl *Dcl);
+    void RewriteImplementationDecl(Decl *Dcl);
+    void RewriteObjCMethodDecl(const ObjCInterfaceDecl *IDecl,
+                               ObjCMethodDecl *MDecl, std::string &ResultStr);
+    void RewriteTypeIntoString(QualType T, std::string &ResultStr,
+                               const FunctionType *&FPRetType);
+    void RewriteByRefString(std::string &ResultStr, const std::string &Name,
+                            ValueDecl *VD, bool def=false);
+    void RewriteCategoryDecl(ObjCCategoryDecl *Dcl);
+    void RewriteProtocolDecl(ObjCProtocolDecl *Dcl);
+    void RewriteForwardProtocolDecl(DeclGroupRef D);
+    void RewriteForwardProtocolDecl(const SmallVectorImpl<Decl *> &DG);
+    void RewriteMethodDeclaration(ObjCMethodDecl *Method);
+    void RewriteProperty(ObjCPropertyDecl *prop);
+    void RewriteFunctionDecl(FunctionDecl *FD);
+    void RewriteBlockPointerType(std::string& Str, QualType Type);
+    void RewriteBlockPointerTypeVariable(std::string& Str, ValueDecl *VD);
+    void RewriteBlockLiteralFunctionDecl(FunctionDecl *FD);
+    void RewriteObjCQualifiedInterfaceTypes(Decl *Dcl);
+    void RewriteTypeOfDecl(VarDecl *VD);
+    void RewriteObjCQualifiedInterfaceTypes(Expr *E);
+  
+    // Expression Rewriting.
+    Stmt *RewriteFunctionBodyOrGlobalInitializer(Stmt *S);
+    Stmt *RewriteAtEncode(ObjCEncodeExpr *Exp);
+    Stmt *RewritePropertyOrImplicitGetter(PseudoObjectExpr *Pseudo);
+    Stmt *RewritePropertyOrImplicitSetter(PseudoObjectExpr *Pseudo);
+    Stmt *RewriteAtSelector(ObjCSelectorExpr *Exp);
+    Stmt *RewriteMessageExpr(ObjCMessageExpr *Exp);
+    Stmt *RewriteObjCStringLiteral(ObjCStringLiteral *Exp);
+    Stmt *RewriteObjCProtocolExpr(ObjCProtocolExpr *Exp);
+    void RewriteTryReturnStmts(Stmt *S);
+    void RewriteSyncReturnStmts(Stmt *S, std::string buf);
+    Stmt *RewriteObjCTryStmt(ObjCAtTryStmt *S);
+    Stmt *RewriteObjCSynchronizedStmt(ObjCAtSynchronizedStmt *S);
+    Stmt *RewriteObjCThrowStmt(ObjCAtThrowStmt *S);
+    Stmt *RewriteObjCForCollectionStmt(ObjCForCollectionStmt *S,
+                                       SourceLocation OrigEnd);
+    Stmt *RewriteBreakStmt(BreakStmt *S);
+    Stmt *RewriteContinueStmt(ContinueStmt *S);
+    void RewriteCastExpr(CStyleCastExpr *CE);
+    
+    // Block rewriting.
+    void RewriteBlocksInFunctionProtoType(QualType funcType, NamedDecl *D);
+    
+    // Block specific rewrite rules.
+    void RewriteBlockPointerDecl(NamedDecl *VD);
+    void RewriteByRefVar(VarDecl *VD);
+    Stmt *RewriteBlockDeclRefExpr(DeclRefExpr *VD);
+    Stmt *RewriteLocalVariableExternalStorage(DeclRefExpr *DRE);
+    void RewriteBlockPointerFunctionArgs(FunctionDecl *FD);
+    
+    void RewriteObjCInternalStruct(ObjCInterfaceDecl *CDecl,
+                                      std::string &Result);
+
+    virtual void Initialize(ASTContext &context) override = 0;
+
+    // Metadata Rewriting.
+    virtual void RewriteMetaDataIntoBuffer(std::string &Result) = 0;
+    virtual void RewriteObjCProtocolListMetaData(const ObjCList<ObjCProtocolDecl> &Prots,
+                                                 StringRef prefix,
+                                                 StringRef ClassName,
+                                                 std::string &Result) = 0;
+    virtual void RewriteObjCCategoryImplDecl(ObjCCategoryImplDecl *CDecl,
+                                             std::string &Result) = 0;
+    virtual void RewriteObjCProtocolMetaData(ObjCProtocolDecl *Protocol,
+                                     StringRef prefix,
+                                     StringRef ClassName,
+                                     std::string &Result) = 0;
+    virtual void RewriteObjCClassMetaData(ObjCImplementationDecl *IDecl,
+                                          std::string &Result) = 0;
+    
+    // Rewriting ivar access
+    virtual Stmt *RewriteObjCIvarRefExpr(ObjCIvarRefExpr *IV) = 0;
+    virtual void RewriteIvarOffsetComputation(ObjCIvarDecl *ivar,
+                                         std::string &Result) = 0;
+    
+    // Misc. AST transformation routines. Sometimes they end up calling
+    // rewriting routines on the new ASTs.
+    CallExpr *SynthesizeCallToFunctionDecl(FunctionDecl *FD,
+                                           Expr **args, unsigned nargs,
+                                           SourceLocation StartLoc=SourceLocation(),
+                                           SourceLocation EndLoc=SourceLocation());
+    CallExpr *SynthMsgSendStretCallExpr(FunctionDecl *MsgSendStretFlavor,
+                                        QualType msgSendType, 
+                                        QualType returnType, 
+                                        SmallVectorImpl<QualType> &ArgTypes,
+                                        SmallVectorImpl<Expr*> &MsgExprs,
+                                        ObjCMethodDecl *Method);
+    Stmt *SynthMessageExpr(ObjCMessageExpr *Exp,
+                           SourceLocation StartLoc=SourceLocation(),
+                           SourceLocation EndLoc=SourceLocation());
+    
+    void SynthCountByEnumWithState(std::string &buf);
+    void SynthMsgSendFunctionDecl();
+    void SynthMsgSendSuperFunctionDecl();
+    void SynthMsgSendStretFunctionDecl();
+    void SynthMsgSendFpretFunctionDecl();
+    void SynthMsgSendSuperStretFunctionDecl();
+    void SynthGetClassFunctionDecl();
+    void SynthGetMetaClassFunctionDecl();
+    void SynthGetSuperClassFunctionDecl();
+    void SynthSelGetUidFunctionDecl();
+    void SynthSuperConstructorFunctionDecl();
+    
+    std::string SynthesizeByrefCopyDestroyHelper(VarDecl *VD, int flag);
+    std::string SynthesizeBlockHelperFuncs(BlockExpr *CE, int i,
+                                      StringRef funcName, std::string Tag);
+    std::string SynthesizeBlockFunc(BlockExpr *CE, int i,
+                                      StringRef funcName, std::string Tag);
+    std::string SynthesizeBlockImpl(BlockExpr *CE, 
+                                    std::string Tag, std::string Desc);
+    std::string SynthesizeBlockDescriptor(std::string DescTag, 
+                                          std::string ImplTag,
+                                          int i, StringRef funcName,
+                                          unsigned hasCopy);
+    Stmt *SynthesizeBlockCall(CallExpr *Exp, const Expr* BlockExp);
+    void SynthesizeBlockLiterals(SourceLocation FunLocStart,
+                                 StringRef FunName);
+    FunctionDecl *SynthBlockInitFunctionDecl(StringRef name);
+    Stmt *SynthBlockInitExpr(BlockExpr *Exp,
+            const SmallVectorImpl<DeclRefExpr *> &InnerBlockDeclRefs);
+
+    // Misc. helper routines.
+    QualType getProtocolType();
+    void WarnAboutReturnGotoStmts(Stmt *S);
+    void HasReturnStmts(Stmt *S, bool &hasReturns);
+    void CheckFunctionPointerDecl(QualType dType, NamedDecl *ND);
+    void InsertBlockLiteralsWithinFunction(FunctionDecl *FD);
+    void InsertBlockLiteralsWithinMethod(ObjCMethodDecl *MD);
+
+    bool IsDeclStmtInForeachHeader(DeclStmt *DS);
+    void CollectBlockDeclRefInfo(BlockExpr *Exp);
+    void GetBlockDeclRefExprs(Stmt *S);
+    void GetInnerBlockDeclRefExprs(Stmt *S,
+                SmallVectorImpl<DeclRefExpr *> &InnerBlockDeclRefs,
+                llvm::SmallPtrSet<const DeclContext *, 8> &InnerContexts);
+
+    // We avoid calling Type::isBlockPointerType(), since it operates on the
+    // canonical type. We only care if the top-level type is a closure pointer.
+    bool isTopLevelBlockPointerType(QualType T) {
+      return isa<BlockPointerType>(T);
+    }
+
+    /// convertBlockPointerToFunctionPointer - Converts a block-pointer type
+    /// to a function pointer type and upon success, returns true; false
+    /// otherwise.
+    bool convertBlockPointerToFunctionPointer(QualType &T) {
+      if (isTopLevelBlockPointerType(T)) {
+        const BlockPointerType *BPT = T->getAs<BlockPointerType>();
+        T = Context->getPointerType(BPT->getPointeeType());
+        return true;
+      }
+      return false;
+    }
+    
+    bool needToScanForQualifiers(QualType T);
+    QualType getSuperStructType();
+    QualType getConstantStringStructType();
+    QualType convertFunctionTypeOfBlocks(const FunctionType *FT);
+    bool BufferContainsPPDirectives(const char *startBuf, const char *endBuf);
+    
+    void convertToUnqualifiedObjCType(QualType &T) {
+      if (T->isObjCQualifiedIdType())
+        T = Context->getObjCIdType();
+      else if (T->isObjCQualifiedClassType())
+        T = Context->getObjCClassType();
+      else if (T->isObjCObjectPointerType() &&
+               T->getPointeeType()->isObjCQualifiedInterfaceType()) {
+        if (const ObjCObjectPointerType * OBJPT =
+              T->getAsObjCInterfacePointerType()) {
+          const ObjCInterfaceType *IFaceT = OBJPT->getInterfaceType();
+          T = QualType(IFaceT, 0);
+          T = Context->getPointerType(T);
+        }
+     }
+    }
+    
+    // FIXME: This predicate seems like it would be useful to add to ASTContext.
+    bool isObjCType(QualType T) {
+      if (!LangOpts.ObjC1 && !LangOpts.ObjC2)
+        return false;
+
+      QualType OCT = Context->getCanonicalType(T).getUnqualifiedType();
+
+      if (OCT == Context->getCanonicalType(Context->getObjCIdType()) ||
+          OCT == Context->getCanonicalType(Context->getObjCClassType()))
+        return true;
+
+      if (const PointerType *PT = OCT->getAs<PointerType>()) {
+        if (isa<ObjCInterfaceType>(PT->getPointeeType()) ||
+            PT->getPointeeType()->isObjCQualifiedIdType())
+          return true;
+      }
+      return false;
+    }
+    bool PointerTypeTakesAnyBlockArguments(QualType QT);
+    bool PointerTypeTakesAnyObjCQualifiedType(QualType QT);
+    void GetExtentOfArgList(const char *Name, const char *&LParen,
+                            const char *&RParen);
+    
+    void QuoteDoublequotes(std::string &From, std::string &To) {
+      for (unsigned i = 0; i < From.length(); i++) {
+        if (From[i] == '"')
+          To += "\\\"";
+        else
+          To += From[i];
+      }
+    }
+
+    QualType getSimpleFunctionType(QualType result,
+                                   ArrayRef<QualType> args,
+                                   bool variadic = false) {
+      if (result == Context->getObjCInstanceType())
+        result =  Context->getObjCIdType();
+      FunctionProtoType::ExtProtoInfo fpi;
+      fpi.Variadic = variadic;
+      return Context->getFunctionType(result, args, fpi);
+    }
+
+    // Helper function: create a CStyleCastExpr with trivial type source info.
+    CStyleCastExpr* NoTypeInfoCStyleCastExpr(ASTContext *Ctx, QualType Ty,
+                                             CastKind Kind, Expr *E) {
+      TypeSourceInfo *TInfo = Ctx->getTrivialTypeSourceInfo(Ty, SourceLocation());
+      return CStyleCastExpr::Create(*Ctx, Ty, VK_RValue, Kind, E, nullptr,
+                                    TInfo, SourceLocation(), SourceLocation());
+    }
+
+    StringLiteral *getStringLiteral(StringRef Str) {
+      QualType StrType = Context->getConstantArrayType(
+          Context->CharTy, llvm::APInt(32, Str.size() + 1), ArrayType::Normal,
+          0);
+      return StringLiteral::Create(*Context, Str, StringLiteral::Ascii,
+                                   /*Pascal=*/false, StrType, SourceLocation());
+    }
+  };
+  
+  class RewriteObjCFragileABI : public RewriteObjC {
+  public:
+    
+    RewriteObjCFragileABI(std::string inFile, raw_ostream *OS,
+                DiagnosticsEngine &D, const LangOptions &LOpts,
+                bool silenceMacroWarn) : RewriteObjC(inFile, OS,
+                                                     D, LOpts,
+                                                     silenceMacroWarn) {}
+    
+    ~RewriteObjCFragileABI() {}
+    virtual void Initialize(ASTContext &context) override;
+
+    // Rewriting metadata
+    template<typename MethodIterator>
+    void RewriteObjCMethodsMetaData(MethodIterator MethodBegin,
+                                    MethodIterator MethodEnd,
+                                    bool IsInstanceMethod,
+                                    StringRef prefix,
+                                    StringRef ClassName,
+                                    std::string &Result);
+    void RewriteObjCProtocolMetaData(ObjCProtocolDecl *Protocol,
+                                     StringRef prefix, StringRef ClassName,
+                                     std::string &Result) override;
+    void RewriteObjCProtocolListMetaData(
+          const ObjCList<ObjCProtocolDecl> &Prots,
+          StringRef prefix, StringRef ClassName, std::string &Result) override;
+    void RewriteObjCClassMetaData(ObjCImplementationDecl *IDecl,
+                                  std::string &Result) override;
+    void RewriteMetaDataIntoBuffer(std::string &Result) override;
+    void RewriteObjCCategoryImplDecl(ObjCCategoryImplDecl *CDecl,
+                                     std::string &Result) override;
+
+    // Rewriting ivar
+    void RewriteIvarOffsetComputation(ObjCIvarDecl *ivar,
+                                      std::string &Result) override;
+    Stmt *RewriteObjCIvarRefExpr(ObjCIvarRefExpr *IV) override;
+  };
+}
+
+void RewriteObjC::RewriteBlocksInFunctionProtoType(QualType funcType,
+                                                   NamedDecl *D) {
+  if (const FunctionProtoType *fproto
+      = dyn_cast<FunctionProtoType>(funcType.IgnoreParens())) {
+    for (const auto &I : fproto->param_types())
+      if (isTopLevelBlockPointerType(I)) {
+        // All the args are checked/rewritten. Don't call twice!
+        RewriteBlockPointerDecl(D);
+        break;
+      }
+  }
+}
+
+void RewriteObjC::CheckFunctionPointerDecl(QualType funcType, NamedDecl *ND) {
+  const PointerType *PT = funcType->getAs<PointerType>();
+  if (PT && PointerTypeTakesAnyBlockArguments(funcType))
+    RewriteBlocksInFunctionProtoType(PT->getPointeeType(), ND);
+}
+
+static bool IsHeaderFile(const std::string &Filename) {
+  std::string::size_type DotPos = Filename.rfind('.');
+
+  if (DotPos == std::string::npos) {
+    // no file extension
+    return false;
+  }
+
+  std::string Ext = std::string(Filename.begin()+DotPos+1, Filename.end());
+  // C header: .h
+  // C++ header: .hh or .H;
+  return Ext == "h" || Ext == "hh" || Ext == "H";
+}
+
+RewriteObjC::RewriteObjC(std::string inFile, raw_ostream* OS,
+                         DiagnosticsEngine &D, const LangOptions &LOpts,
+                         bool silenceMacroWarn)
+      : Diags(D), LangOpts(LOpts), InFileName(inFile), OutFile(OS),
+        SilenceRewriteMacroWarning(silenceMacroWarn) {
+  IsHeader = IsHeaderFile(inFile);
+  RewriteFailedDiag = Diags.getCustomDiagID(DiagnosticsEngine::Warning,
+               "rewriting sub-expression within a macro (may not be correct)");
+  TryFinallyContainsReturnDiag = Diags.getCustomDiagID(
+               DiagnosticsEngine::Warning,
+               "rewriter doesn't support user-specified control flow semantics "
+               "for @try/@finally (code may not execute properly)");
+}
+
+ASTConsumer *clang::CreateObjCRewriter(const std::string& InFile,
+                                       raw_ostream* OS,
+                                       DiagnosticsEngine &Diags,
+                                       const LangOptions &LOpts,
+                                       bool SilenceRewriteMacroWarning) {
+  return new RewriteObjCFragileABI(InFile, OS, Diags, LOpts, SilenceRewriteMacroWarning);
+}
+
+void RewriteObjC::InitializeCommon(ASTContext &context) {
+  Context = &context;
+  SM = &Context->getSourceManager();
+  TUDecl = Context->getTranslationUnitDecl();
+  MsgSendFunctionDecl = nullptr;
+  MsgSendSuperFunctionDecl = nullptr;
+  MsgSendStretFunctionDecl = nullptr;
+  MsgSendSuperStretFunctionDecl = nullptr;
+  MsgSendFpretFunctionDecl = nullptr;
+  GetClassFunctionDecl = nullptr;
+  GetMetaClassFunctionDecl = nullptr;
+  GetSuperClassFunctionDecl = nullptr;
+  SelGetUidFunctionDecl = nullptr;
+  CFStringFunctionDecl = nullptr;
+  ConstantStringClassReference = nullptr;
+  NSStringRecord = nullptr;
+  CurMethodDef = nullptr;
+  CurFunctionDef = nullptr;
+  CurFunctionDeclToDeclareForBlock = nullptr;
+  GlobalVarDecl = nullptr;
+  SuperStructDecl = nullptr;
+  ProtocolTypeDecl = nullptr;
+  ConstantStringDecl = nullptr;
+  BcLabelCount = 0;
+  SuperConstructorFunctionDecl = nullptr;
+  NumObjCStringLiterals = 0;
+  PropParentMap = nullptr;
+  CurrentBody = nullptr;
+  DisableReplaceStmt = false;
+  objc_impl_method = false;
+
+  // Get the ID and start/end of the main file.
+  MainFileID = SM->getMainFileID();
+  const llvm::MemoryBuffer *MainBuf = SM->getBuffer(MainFileID);
+  MainFileStart = MainBuf->getBufferStart();
+  MainFileEnd = MainBuf->getBufferEnd();
+
+  Rewrite.setSourceMgr(Context->getSourceManager(), Context->getLangOpts());
+}
+
+//===----------------------------------------------------------------------===//
+// Top Level Driver Code
+//===----------------------------------------------------------------------===//
+
+void RewriteObjC::HandleTopLevelSingleDecl(Decl *D) {
+  if (Diags.hasErrorOccurred())
+    return;
+
+  // Two cases: either the decl could be in the main file, or it could be in a
+  // #included file.  If the former, rewrite it now.  If the later, check to see
+  // if we rewrote the #include/#import.
+  SourceLocation Loc = D->getLocation();
+  Loc = SM->getExpansionLoc(Loc);
+
+  // If this is for a builtin, ignore it.
+  if (Loc.isInvalid()) return;
+
+  // Look for built-in declarations that we need to refer during the rewrite.
+  if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
+    RewriteFunctionDecl(FD);
+  } else if (VarDecl *FVD = dyn_cast<VarDecl>(D)) {
+    // declared in <Foundation/NSString.h>
+    if (FVD->getName() == "_NSConstantStringClassReference") {
+      ConstantStringClassReference = FVD;
+      return;
+    }
+  } else if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(D)) {
+    if (ID->isThisDeclarationADefinition())
+      RewriteInterfaceDecl(ID);
+  } else if (ObjCCategoryDecl *CD = dyn_cast<ObjCCategoryDecl>(D)) {
+    RewriteCategoryDecl(CD);
+  } else if (ObjCProtocolDecl *PD = dyn_cast<ObjCProtocolDecl>(D)) {
+    if (PD->isThisDeclarationADefinition())
+      RewriteProtocolDecl(PD);
+  } else if (LinkageSpecDecl *LSD = dyn_cast<LinkageSpecDecl>(D)) {
+    // Recurse into linkage specifications
+    for (DeclContext::decl_iterator DI = LSD->decls_begin(),
+                                 DIEnd = LSD->decls_end();
+         DI != DIEnd; ) {
+      if (ObjCInterfaceDecl *IFace = dyn_cast<ObjCInterfaceDecl>((*DI))) {
+        if (!IFace->isThisDeclarationADefinition()) {
+          SmallVector<Decl *, 8> DG;
+          SourceLocation StartLoc = IFace->getLocStart();
+          do {
+            if (isa<ObjCInterfaceDecl>(*DI) &&
+                !cast<ObjCInterfaceDecl>(*DI)->isThisDeclarationADefinition() &&
+                StartLoc == (*DI)->getLocStart())
+              DG.push_back(*DI);
+            else
+              break;
+            
+            ++DI;
+          } while (DI != DIEnd);
+          RewriteForwardClassDecl(DG);
+          continue;
+        }
+      }
+
+      if (ObjCProtocolDecl *Proto = dyn_cast<ObjCProtocolDecl>((*DI))) {
+        if (!Proto->isThisDeclarationADefinition()) {
+          SmallVector<Decl *, 8> DG;
+          SourceLocation StartLoc = Proto->getLocStart();
+          do {
+            if (isa<ObjCProtocolDecl>(*DI) &&
+                !cast<ObjCProtocolDecl>(*DI)->isThisDeclarationADefinition() &&
+                StartLoc == (*DI)->getLocStart())
+              DG.push_back(*DI);
+            else
+              break;
+            
+            ++DI;
+          } while (DI != DIEnd);
+          RewriteForwardProtocolDecl(DG);
+          continue;
+        }
+      }
+      
+      HandleTopLevelSingleDecl(*DI);
+      ++DI;
+    }
+  }
+  // If we have a decl in the main file, see if we should rewrite it.
+  if (SM->isWrittenInMainFile(Loc))
+    return HandleDeclInMainFile(D);
+}
+
+//===----------------------------------------------------------------------===//
+// Syntactic (non-AST) Rewriting Code
+//===----------------------------------------------------------------------===//
+
+void RewriteObjC::RewriteInclude() {
+  SourceLocation LocStart = SM->getLocForStartOfFile(MainFileID);
+  StringRef MainBuf = SM->getBufferData(MainFileID);
+  const char *MainBufStart = MainBuf.begin();
+  const char *MainBufEnd = MainBuf.end();
+  size_t ImportLen = strlen("import");
+
+  // Loop over the whole file, looking for includes.
+  for (const char *BufPtr = MainBufStart; BufPtr < MainBufEnd; ++BufPtr) {
+    if (*BufPtr == '#') {
+      if (++BufPtr == MainBufEnd)
+        return;
+      while (*BufPtr == ' ' || *BufPtr == '\t')
+        if (++BufPtr == MainBufEnd)
+          return;
+      if (!strncmp(BufPtr, "import", ImportLen)) {
+        // replace import with include
+        SourceLocation ImportLoc =
+          LocStart.getLocWithOffset(BufPtr-MainBufStart);
+        ReplaceText(ImportLoc, ImportLen, "include");
+        BufPtr += ImportLen;
+      }
+    }
+  }
+}
+
+static std::string getIvarAccessString(ObjCIvarDecl *OID) {
+  const ObjCInterfaceDecl *ClassDecl = OID->getContainingInterface();
+  std::string S;
+  S = "((struct ";
+  S += ClassDecl->getIdentifier()->getName();
+  S += "_IMPL *)self)->";
+  S += OID->getName();
+  return S;
+}
+
+void RewriteObjC::RewritePropertyImplDecl(ObjCPropertyImplDecl *PID,
+                                          ObjCImplementationDecl *IMD,
+                                          ObjCCategoryImplDecl *CID) {
+  static bool objcGetPropertyDefined = false;
+  static bool objcSetPropertyDefined = false;
+  SourceLocation startLoc = PID->getLocStart();
+  InsertText(startLoc, "// ");
+  const char *startBuf = SM->getCharacterData(startLoc);
+  assert((*startBuf == '@') && "bogus @synthesize location");
+  const char *semiBuf = strchr(startBuf, ';');
+  assert((*semiBuf == ';') && "@synthesize: can't find ';'");
+  SourceLocation onePastSemiLoc =
+    startLoc.getLocWithOffset(semiBuf-startBuf+1);
+
+  if (PID->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic)
+    return; // FIXME: is this correct?
+
+  // Generate the 'getter' function.
+  ObjCPropertyDecl *PD = PID->getPropertyDecl();
+  ObjCIvarDecl *OID = PID->getPropertyIvarDecl();
+
+  if (!OID)
+    return;
+  unsigned Attributes = PD->getPropertyAttributes();
+  if (!PD->getGetterMethodDecl()->isDefined()) {
+    bool GenGetProperty = !(Attributes & ObjCPropertyDecl::OBJC_PR_nonatomic) &&
+                          (Attributes & (ObjCPropertyDecl::OBJC_PR_retain | 
+                                         ObjCPropertyDecl::OBJC_PR_copy));
+    std::string Getr;
+    if (GenGetProperty && !objcGetPropertyDefined) {
+      objcGetPropertyDefined = true;
+      // FIXME. Is this attribute correct in all cases?
+      Getr = "\nextern \"C\" __declspec(dllimport) "
+            "id objc_getProperty(id, SEL, long, bool);\n";
+    }
+    RewriteObjCMethodDecl(OID->getContainingInterface(),  
+                          PD->getGetterMethodDecl(), Getr);
+    Getr += "{ ";
+    // Synthesize an explicit cast to gain access to the ivar.
+    // See objc-act.c:objc_synthesize_new_getter() for details.
+    if (GenGetProperty) {
+      // return objc_getProperty(self, _cmd, offsetof(ClassDecl, OID), 1)
+      Getr += "typedef ";
+      const FunctionType *FPRetType = nullptr;
+      RewriteTypeIntoString(PD->getGetterMethodDecl()->getReturnType(), Getr,
+                            FPRetType);
+      Getr += " _TYPE";
+      if (FPRetType) {
+        Getr += ")"; // close the precedence "scope" for "*".
+      
+        // Now, emit the argument types (if any).
+        if (const FunctionProtoType *FT = dyn_cast<FunctionProtoType>(FPRetType)){
+          Getr += "(";
+          for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) {
+            if (i) Getr += ", ";
+            std::string ParamStr =
+                FT->getParamType(i).getAsString(Context->getPrintingPolicy());
+            Getr += ParamStr;
+          }
+          if (FT->isVariadic()) {
+            if (FT->getNumParams())
+              Getr += ", ";
+            Getr += "...";
+          }
+          Getr += ")";
+        } else
+          Getr += "()";
+      }
+      Getr += ";\n";
+      Getr += "return (_TYPE)";
+      Getr += "objc_getProperty(self, _cmd, ";
+      RewriteIvarOffsetComputation(OID, Getr);
+      Getr += ", 1)";
+    }
+    else
+      Getr += "return " + getIvarAccessString(OID);
+    Getr += "; }";
+    InsertText(onePastSemiLoc, Getr);
+  }
+  
+  if (PD->isReadOnly() || PD->getSetterMethodDecl()->isDefined())
+    return;
+
+  // Generate the 'setter' function.
+  std::string Setr;
+  bool GenSetProperty = Attributes & (ObjCPropertyDecl::OBJC_PR_retain | 
+                                      ObjCPropertyDecl::OBJC_PR_copy);
+  if (GenSetProperty && !objcSetPropertyDefined) {
+    objcSetPropertyDefined = true;
+    // FIXME. Is this attribute correct in all cases?
+    Setr = "\nextern \"C\" __declspec(dllimport) "
+    "void objc_setProperty (id, SEL, long, id, bool, bool);\n";
+  }
+  
+  RewriteObjCMethodDecl(OID->getContainingInterface(), 
+                        PD->getSetterMethodDecl(), Setr);
+  Setr += "{ ";
+  // Synthesize an explicit cast to initialize the ivar.
+  // See objc-act.c:objc_synthesize_new_setter() for details.
+  if (GenSetProperty) {
+    Setr += "objc_setProperty (self, _cmd, ";
+    RewriteIvarOffsetComputation(OID, Setr);
+    Setr += ", (id)";
+    Setr += PD->getName();
+    Setr += ", ";
+    if (Attributes & ObjCPropertyDecl::OBJC_PR_nonatomic)
+      Setr += "0, ";
+    else
+      Setr += "1, ";
+    if (Attributes & ObjCPropertyDecl::OBJC_PR_copy)
+      Setr += "1)";
+    else
+      Setr += "0)";
+  }
+  else {
+    Setr += getIvarAccessString(OID) + " = ";
+    Setr += PD->getName();
+  }
+  Setr += "; }";
+  InsertText(onePastSemiLoc, Setr);
+}
+
+static void RewriteOneForwardClassDecl(ObjCInterfaceDecl *ForwardDecl,
+                                       std::string &typedefString) {
+  typedefString += "#ifndef _REWRITER_typedef_";
+  typedefString += ForwardDecl->getNameAsString();
+  typedefString += "\n";
+  typedefString += "#define _REWRITER_typedef_";
+  typedefString += ForwardDecl->getNameAsString();
+  typedefString += "\n";
+  typedefString += "typedef struct objc_object ";
+  typedefString += ForwardDecl->getNameAsString();
+  typedefString += ";\n#endif\n";
+}
+
+void RewriteObjC::RewriteForwardClassEpilogue(ObjCInterfaceDecl *ClassDecl,
+                                              const std::string &typedefString) {
+    SourceLocation startLoc = ClassDecl->getLocStart();
+    const char *startBuf = SM->getCharacterData(startLoc);
+    const char *semiPtr = strchr(startBuf, ';'); 
+    // Replace the @class with typedefs corresponding to the classes.
+    ReplaceText(startLoc, semiPtr-startBuf+1, typedefString);  
+}
+
+void RewriteObjC::RewriteForwardClassDecl(DeclGroupRef D) {
+  std::string typedefString;
+  for (DeclGroupRef::iterator I = D.begin(), E = D.end(); I != E; ++I) {
+    ObjCInterfaceDecl *ForwardDecl = cast<ObjCInterfaceDecl>(*I);
+    if (I == D.begin()) {
+      // Translate to typedef's that forward reference structs with the same name
+      // as the class. As a convenience, we include the original declaration
+      // as a comment.
+      typedefString += "// @class ";
+      typedefString += ForwardDecl->getNameAsString();
+      typedefString += ";\n";
+    }
+    RewriteOneForwardClassDecl(ForwardDecl, typedefString);
+  }
+  DeclGroupRef::iterator I = D.begin();
+  RewriteForwardClassEpilogue(cast<ObjCInterfaceDecl>(*I), typedefString);
+}
+
+void RewriteObjC::RewriteForwardClassDecl(const SmallVectorImpl<Decl *> &D) {
+  std::string typedefString;
+  for (unsigned i = 0; i < D.size(); i++) {
+    ObjCInterfaceDecl *ForwardDecl = cast<ObjCInterfaceDecl>(D[i]);
+    if (i == 0) {
+      typedefString += "// @class ";
+      typedefString += ForwardDecl->getNameAsString();
+      typedefString += ";\n";
+    }
+    RewriteOneForwardClassDecl(ForwardDecl, typedefString);
+  }
+  RewriteForwardClassEpilogue(cast<ObjCInterfaceDecl>(D[0]), typedefString);
+}
+
+void RewriteObjC::RewriteMethodDeclaration(ObjCMethodDecl *Method) {
+  // When method is a synthesized one, such as a getter/setter there is
+  // nothing to rewrite.
+  if (Method->isImplicit())
+    return;
+  SourceLocation LocStart = Method->getLocStart();
+  SourceLocation LocEnd = Method->getLocEnd();
+
+  if (SM->getExpansionLineNumber(LocEnd) >
+      SM->getExpansionLineNumber(LocStart)) {
+    InsertText(LocStart, "#if 0\n");
+    ReplaceText(LocEnd, 1, ";\n#endif\n");
+  } else {
+    InsertText(LocStart, "// ");
+  }
+}
+
+void RewriteObjC::RewriteProperty(ObjCPropertyDecl *prop) {
+  SourceLocation Loc = prop->getAtLoc();
+
+  ReplaceText(Loc, 0, "// ");
+  // FIXME: handle properties that are declared across multiple lines.
+}
+
+void RewriteObjC::RewriteCategoryDecl(ObjCCategoryDecl *CatDecl) {
+  SourceLocation LocStart = CatDecl->getLocStart();
+
+  // FIXME: handle category headers that are declared across multiple lines.
+  ReplaceText(LocStart, 0, "// ");
+
+  for (auto *I : CatDecl->properties())
+    RewriteProperty(I);  
+  for (auto *I : CatDecl->instance_methods())
+    RewriteMethodDeclaration(I);
+  for (auto *I : CatDecl->class_methods())
+    RewriteMethodDeclaration(I);
+
+  // Lastly, comment out the @end.
+  ReplaceText(CatDecl->getAtEndRange().getBegin(), 
+              strlen("@end"), "/* @end */");
+}
+
+void RewriteObjC::RewriteProtocolDecl(ObjCProtocolDecl *PDecl) {
+  SourceLocation LocStart = PDecl->getLocStart();
+  assert(PDecl->isThisDeclarationADefinition());
+  
+  // FIXME: handle protocol headers that are declared across multiple lines.
+  ReplaceText(LocStart, 0, "// ");
+
+  for (auto *I : PDecl->instance_methods())
+    RewriteMethodDeclaration(I);
+  for (auto *I : PDecl->class_methods())
+    RewriteMethodDeclaration(I);
+  for (auto *I : PDecl->properties())
+    RewriteProperty(I);
+  
+  // Lastly, comment out the @end.
+  SourceLocation LocEnd = PDecl->getAtEndRange().getBegin();
+  ReplaceText(LocEnd, strlen("@end"), "/* @end */");
+
+  // Must comment out @optional/@required
+  const char *startBuf = SM->getCharacterData(LocStart);
+  const char *endBuf = SM->getCharacterData(LocEnd);
+  for (const char *p = startBuf; p < endBuf; p++) {
+    if (*p == '@' && !strncmp(p+1, "optional", strlen("optional"))) {
+      SourceLocation OptionalLoc = LocStart.getLocWithOffset(p-startBuf);
+      ReplaceText(OptionalLoc, strlen("@optional"), "/* @optional */");
+
+    }
+    else if (*p == '@' && !strncmp(p+1, "required", strlen("required"))) {
+      SourceLocation OptionalLoc = LocStart.getLocWithOffset(p-startBuf);
+      ReplaceText(OptionalLoc, strlen("@required"), "/* @required */");
+
+    }
+  }
+}
+
+void RewriteObjC::RewriteForwardProtocolDecl(DeclGroupRef D) {
+  SourceLocation LocStart = (*D.begin())->getLocStart();
+  if (LocStart.isInvalid())
+    llvm_unreachable("Invalid SourceLocation");
+  // FIXME: handle forward protocol that are declared across multiple lines.
+  ReplaceText(LocStart, 0, "// ");
+}
+
+void 
+RewriteObjC::RewriteForwardProtocolDecl(const SmallVectorImpl<Decl *> &DG) {
+  SourceLocation LocStart = DG[0]->getLocStart();
+  if (LocStart.isInvalid())
+    llvm_unreachable("Invalid SourceLocation");
+  // FIXME: handle forward protocol that are declared across multiple lines.
+  ReplaceText(LocStart, 0, "// ");
+}
+
+void RewriteObjC::RewriteTypeIntoString(QualType T, std::string &ResultStr,
+                                        const FunctionType *&FPRetType) {
+  if (T->isObjCQualifiedIdType())
+    ResultStr += "id";
+  else if (T->isFunctionPointerType() ||
+           T->isBlockPointerType()) {
+    // needs special handling, since pointer-to-functions have special
+    // syntax (where a decaration models use).
+    QualType retType = T;
+    QualType PointeeTy;
+    if (const PointerType* PT = retType->getAs<PointerType>())
+      PointeeTy = PT->getPointeeType();
+    else if (const BlockPointerType *BPT = retType->getAs<BlockPointerType>())
+      PointeeTy = BPT->getPointeeType();
+    if ((FPRetType = PointeeTy->getAs<FunctionType>())) {
+      ResultStr +=
+          FPRetType->getReturnType().getAsString(Context->getPrintingPolicy());
+      ResultStr += "(*";
+    }
+  } else
+    ResultStr += T.getAsString(Context->getPrintingPolicy());
+}
+
+void RewriteObjC::RewriteObjCMethodDecl(const ObjCInterfaceDecl *IDecl,
+                                        ObjCMethodDecl *OMD,
+                                        std::string &ResultStr) {
+  //fprintf(stderr,"In RewriteObjCMethodDecl\n");
+  const FunctionType *FPRetType = nullptr;
+  ResultStr += "\nstatic ";
+  RewriteTypeIntoString(OMD->getReturnType(), ResultStr, FPRetType);
+  ResultStr += " ";
+
+  // Unique method name
+  std::string NameStr;
+
+  if (OMD->isInstanceMethod())
+    NameStr += "_I_";
+  else
+    NameStr += "_C_";
+
+  NameStr += IDecl->getNameAsString();
+  NameStr += "_";
+
+  if (ObjCCategoryImplDecl *CID =
+      dyn_cast<ObjCCategoryImplDecl>(OMD->getDeclContext())) {
+    NameStr += CID->getNameAsString();
+    NameStr += "_";
+  }
+  // Append selector names, replacing ':' with '_'
+  {
+    std::string selString = OMD->getSelector().getAsString();
+    int len = selString.size();
+    for (int i = 0; i < len; i++)
+      if (selString[i] == ':')
+        selString[i] = '_';
+    NameStr += selString;
+  }
+  // Remember this name for metadata emission
+  MethodInternalNames[OMD] = NameStr;
+  ResultStr += NameStr;
+
+  // Rewrite arguments
+  ResultStr += "(";
+
+  // invisible arguments
+  if (OMD->isInstanceMethod()) {
+    QualType selfTy = Context->getObjCInterfaceType(IDecl);
+    selfTy = Context->getPointerType(selfTy);
+    if (!LangOpts.MicrosoftExt) {
+      if (ObjCSynthesizedStructs.count(const_cast<ObjCInterfaceDecl*>(IDecl)))
+        ResultStr += "struct ";
+    }
+    // When rewriting for Microsoft, explicitly omit the structure name.
+    ResultStr += IDecl->getNameAsString();
+    ResultStr += " *";
+  }
+  else
+    ResultStr += Context->getObjCClassType().getAsString(
+      Context->getPrintingPolicy());
+
+  ResultStr += " self, ";
+  ResultStr += Context->getObjCSelType().getAsString(Context->getPrintingPolicy());
+  ResultStr += " _cmd";
+
+  // Method arguments.
+  for (const auto *PDecl : OMD->params()) {
+    ResultStr += ", ";
+    if (PDecl->getType()->isObjCQualifiedIdType()) {
+      ResultStr += "id ";
+      ResultStr += PDecl->getNameAsString();
+    } else {
+      std::string Name = PDecl->getNameAsString();
+      QualType QT = PDecl->getType();
+      // Make sure we convert "t (^)(...)" to "t (*)(...)".
+      (void)convertBlockPointerToFunctionPointer(QT);
+      QT.getAsStringInternal(Name, Context->getPrintingPolicy());
+      ResultStr += Name;
+    }
+  }
+  if (OMD->isVariadic())
+    ResultStr += ", ...";
+  ResultStr += ") ";
+
+  if (FPRetType) {
+    ResultStr += ")"; // close the precedence "scope" for "*".
+
+    // Now, emit the argument types (if any).
+    if (const FunctionProtoType *FT = dyn_cast<FunctionProtoType>(FPRetType)) {
+      ResultStr += "(";
+      for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) {
+        if (i) ResultStr += ", ";
+        std::string ParamStr =
+            FT->getParamType(i).getAsString(Context->getPrintingPolicy());
+        ResultStr += ParamStr;
+      }
+      if (FT->isVariadic()) {
+        if (FT->getNumParams())
+          ResultStr += ", ";
+        ResultStr += "...";
+      }
+      ResultStr += ")";
+    } else {
+      ResultStr += "()";
+    }
+  }
+}
+void RewriteObjC::RewriteImplementationDecl(Decl *OID) {
+  ObjCImplementationDecl *IMD = dyn_cast<ObjCImplementationDecl>(OID);
+  ObjCCategoryImplDecl *CID = dyn_cast<ObjCCategoryImplDecl>(OID);
+
+  InsertText(IMD ? IMD->getLocStart() : CID->getLocStart(), "// ");
+
+  for (auto *OMD : IMD ? IMD->instance_methods() : CID->instance_methods()) {
+    std::string ResultStr;
+    RewriteObjCMethodDecl(OMD->getClassInterface(), OMD, ResultStr);
+    SourceLocation LocStart = OMD->getLocStart();
+    SourceLocation LocEnd = OMD->getCompoundBody()->getLocStart();
+
+    const char *startBuf = SM->getCharacterData(LocStart);
+    const char *endBuf = SM->getCharacterData(LocEnd);
+    ReplaceText(LocStart, endBuf-startBuf, ResultStr);
+  }
+
+  for (auto *OMD : IMD ? IMD->class_methods() : CID->class_methods()) {
+    std::string ResultStr;
+    RewriteObjCMethodDecl(OMD->getClassInterface(), OMD, ResultStr);
+    SourceLocation LocStart = OMD->getLocStart();
+    SourceLocation LocEnd = OMD->getCompoundBody()->getLocStart();
+
+    const char *startBuf = SM->getCharacterData(LocStart);
+    const char *endBuf = SM->getCharacterData(LocEnd);
+    ReplaceText(LocStart, endBuf-startBuf, ResultStr);
+  }
+  for (auto *I : IMD ? IMD->property_impls() : CID->property_impls())
+    RewritePropertyImplDecl(I, IMD, CID);
+
+  InsertText(IMD ? IMD->getLocEnd() : CID->getLocEnd(), "// ");
+}
+
+void RewriteObjC::RewriteInterfaceDecl(ObjCInterfaceDecl *ClassDecl) {
+  std::string ResultStr;
+  if (!ObjCForwardDecls.count(ClassDecl->getCanonicalDecl())) {
+    // we haven't seen a forward decl - generate a typedef.
+    ResultStr = "#ifndef _REWRITER_typedef_";
+    ResultStr += ClassDecl->getNameAsString();
+    ResultStr += "\n";
+    ResultStr += "#define _REWRITER_typedef_";
+    ResultStr += ClassDecl->getNameAsString();
+    ResultStr += "\n";
+    ResultStr += "typedef struct objc_object ";
+    ResultStr += ClassDecl->getNameAsString();
+    ResultStr += ";\n#endif\n";
+    // Mark this typedef as having been generated.
+    ObjCForwardDecls.insert(ClassDecl->getCanonicalDecl());
+  }
+  RewriteObjCInternalStruct(ClassDecl, ResultStr);
+
+  for (auto *I : ClassDecl->properties())
+    RewriteProperty(I);
+  for (auto *I : ClassDecl->instance_methods())
+    RewriteMethodDeclaration(I);
+  for (auto *I : ClassDecl->class_methods())
+    RewriteMethodDeclaration(I);
+
+  // Lastly, comment out the @end.
+  ReplaceText(ClassDecl->getAtEndRange().getBegin(), strlen("@end"), 
+              "/* @end */");
+}
+
+Stmt *RewriteObjC::RewritePropertyOrImplicitSetter(PseudoObjectExpr *PseudoOp) {
+  SourceRange OldRange = PseudoOp->getSourceRange();
+
+  // We just magically know some things about the structure of this
+  // expression.
+  ObjCMessageExpr *OldMsg =
+    cast<ObjCMessageExpr>(PseudoOp->getSemanticExpr(
+                            PseudoOp->getNumSemanticExprs() - 1));
+
+  // Because the rewriter doesn't allow us to rewrite rewritten code,
+  // we need to suppress rewriting the sub-statements.
+  Expr *Base, *RHS;
+  {
+    DisableReplaceStmtScope S(*this);
+
+    // Rebuild the base expression if we have one.
+    Base = nullptr;
+    if (OldMsg->getReceiverKind() == ObjCMessageExpr::Instance) {
+      Base = OldMsg->getInstanceReceiver();
+      Base = cast<OpaqueValueExpr>(Base)->getSourceExpr();
+      Base = cast<Expr>(RewriteFunctionBodyOrGlobalInitializer(Base));
+    }
+
+    // Rebuild the RHS.
+    RHS = cast<BinaryOperator>(PseudoOp->getSyntacticForm())->getRHS();
+    RHS = cast<OpaqueValueExpr>(RHS)->getSourceExpr();
+    RHS = cast<Expr>(RewriteFunctionBodyOrGlobalInitializer(RHS));
+  }
+
+  // TODO: avoid this copy.
+  SmallVector<SourceLocation, 1> SelLocs;
+  OldMsg->getSelectorLocs(SelLocs);
+
+  ObjCMessageExpr *NewMsg = nullptr;
+  switch (OldMsg->getReceiverKind()) {
+  case ObjCMessageExpr::Class:
+    NewMsg = ObjCMessageExpr::Create(*Context, OldMsg->getType(),
+                                     OldMsg->getValueKind(),
+                                     OldMsg->getLeftLoc(),
+                                     OldMsg->getClassReceiverTypeInfo(),
+                                     OldMsg->getSelector(),
+                                     SelLocs,
+                                     OldMsg->getMethodDecl(),
+                                     RHS,
+                                     OldMsg->getRightLoc(),
+                                     OldMsg->isImplicit());
+    break;
+
+  case ObjCMessageExpr::Instance:
+    NewMsg = ObjCMessageExpr::Create(*Context, OldMsg->getType(),
+                                     OldMsg->getValueKind(),
+                                     OldMsg->getLeftLoc(),
+                                     Base,
+                                     OldMsg->getSelector(),
+                                     SelLocs,
+                                     OldMsg->getMethodDecl(),
+                                     RHS,
+                                     OldMsg->getRightLoc(),
+                                     OldMsg->isImplicit());
+    break;
+
+  case ObjCMessageExpr::SuperClass:
+  case ObjCMessageExpr::SuperInstance:
+    NewMsg = ObjCMessageExpr::Create(*Context, OldMsg->getType(),
+                                     OldMsg->getValueKind(),
+                                     OldMsg->getLeftLoc(),
+                                     OldMsg->getSuperLoc(),
+                 OldMsg->getReceiverKind() == ObjCMessageExpr::SuperInstance,
+                                     OldMsg->getSuperType(),
+                                     OldMsg->getSelector(),
+                                     SelLocs,
+                                     OldMsg->getMethodDecl(),
+                                     RHS,
+                                     OldMsg->getRightLoc(),
+                                     OldMsg->isImplicit());
+    break;
+  }
+
+  Stmt *Replacement = SynthMessageExpr(NewMsg);
+  ReplaceStmtWithRange(PseudoOp, Replacement, OldRange);
+  return Replacement;
+}
+
+Stmt *RewriteObjC::RewritePropertyOrImplicitGetter(PseudoObjectExpr *PseudoOp) {
+  SourceRange OldRange = PseudoOp->getSourceRange();
+
+  // We just magically know some things about the structure of this
+  // expression.
+  ObjCMessageExpr *OldMsg =
+    cast<ObjCMessageExpr>(PseudoOp->getResultExpr()->IgnoreImplicit());
+
+  // Because the rewriter doesn't allow us to rewrite rewritten code,
+  // we need to suppress rewriting the sub-statements.
+  Expr *Base = nullptr;
+  {
+    DisableReplaceStmtScope S(*this);
+
+    // Rebuild the base expression if we have one.
+    if (OldMsg->getReceiverKind() == ObjCMessageExpr::Instance) {
+      Base = OldMsg->getInstanceReceiver();
+      Base = cast<OpaqueValueExpr>(Base)->getSourceExpr();
+      Base = cast<Expr>(RewriteFunctionBodyOrGlobalInitializer(Base));
+    }
+  }
+
+  // Intentionally empty.
+  SmallVector<SourceLocation, 1> SelLocs;
+  SmallVector<Expr*, 1> Args;
+
+  ObjCMessageExpr *NewMsg = nullptr;
+  switch (OldMsg->getReceiverKind()) {
+  case ObjCMessageExpr::Class:
+    NewMsg = ObjCMessageExpr::Create(*Context, OldMsg->getType(),
+                                     OldMsg->getValueKind(),
+                                     OldMsg->getLeftLoc(),
+                                     OldMsg->getClassReceiverTypeInfo(),
+                                     OldMsg->getSelector(),
+                                     SelLocs,
+                                     OldMsg->getMethodDecl(),
+                                     Args,
+                                     OldMsg->getRightLoc(),
+                                     OldMsg->isImplicit());
+    break;
+
+  case ObjCMessageExpr::Instance:
+    NewMsg = ObjCMessageExpr::Create(*Context, OldMsg->getType(),
+                                     OldMsg->getValueKind(),
+                                     OldMsg->getLeftLoc(),
+                                     Base,
+                                     OldMsg->getSelector(),
+                                     SelLocs,
+                                     OldMsg->getMethodDecl(),
+                                     Args,
+                                     OldMsg->getRightLoc(),
+                                     OldMsg->isImplicit());
+    break;
+
+  case ObjCMessageExpr::SuperClass:
+  case ObjCMessageExpr::SuperInstance:
+    NewMsg = ObjCMessageExpr::Create(*Context, OldMsg->getType(),
+                                     OldMsg->getValueKind(),
+                                     OldMsg->getLeftLoc(),
+                                     OldMsg->getSuperLoc(),
+                 OldMsg->getReceiverKind() == ObjCMessageExpr::SuperInstance,
+                                     OldMsg->getSuperType(),
+                                     OldMsg->getSelector(),
+                                     SelLocs,
+                                     OldMsg->getMethodDecl(),
+                                     Args,
+                                     OldMsg->getRightLoc(),
+                                     OldMsg->isImplicit());
+    break;
+  }
+
+  Stmt *Replacement = SynthMessageExpr(NewMsg);
+  ReplaceStmtWithRange(PseudoOp, Replacement, OldRange);
+  return Replacement;
+}
+
+/// SynthCountByEnumWithState - To print:
+/// ((unsigned int (*)
+///  (id, SEL, struct __objcFastEnumerationState *, id *, unsigned int))
+///  (void *)objc_msgSend)((id)l_collection,
+///                        sel_registerName(
+///                          "countByEnumeratingWithState:objects:count:"),
+///                        &enumState,
+///                        (id *)__rw_items, (unsigned int)16)
+///
+void RewriteObjC::SynthCountByEnumWithState(std::string &buf) {
+  buf += "((unsigned int (*) (id, SEL, struct __objcFastEnumerationState *, "
+  "id *, unsigned int))(void *)objc_msgSend)";
+  buf += "\n\t\t";
+  buf += "((id)l_collection,\n\t\t";
+  buf += "sel_registerName(\"countByEnumeratingWithState:objects:count:\"),";
+  buf += "\n\t\t";
+  buf += "&enumState, "
+         "(id *)__rw_items, (unsigned int)16)";
+}
+
+/// RewriteBreakStmt - Rewrite for a break-stmt inside an ObjC2's foreach
+/// statement to exit to its outer synthesized loop.
+///
+Stmt *RewriteObjC::RewriteBreakStmt(BreakStmt *S) {
+  if (Stmts.empty() || !isa<ObjCForCollectionStmt>(Stmts.back()))
+    return S;
+  // replace break with goto __break_label
+  std::string buf;
+
+  SourceLocation startLoc = S->getLocStart();
+  buf = "goto __break_label_";
+  buf += utostr(ObjCBcLabelNo.back());
+  ReplaceText(startLoc, strlen("break"), buf);
+
+  return nullptr;
+}
+
+/// RewriteContinueStmt - Rewrite for a continue-stmt inside an ObjC2's foreach
+/// statement to continue with its inner synthesized loop.
+///
+Stmt *RewriteObjC::RewriteContinueStmt(ContinueStmt *S) {
+  if (Stmts.empty() || !isa<ObjCForCollectionStmt>(Stmts.back()))
+    return S;
+  // replace continue with goto __continue_label
+  std::string buf;
+
+  SourceLocation startLoc = S->getLocStart();
+  buf = "goto __continue_label_";
+  buf += utostr(ObjCBcLabelNo.back());
+  ReplaceText(startLoc, strlen("continue"), buf);
+
+  return nullptr;
+}
+
+/// RewriteObjCForCollectionStmt - Rewriter for ObjC2's foreach statement.
+///  It rewrites:
+/// for ( type elem in collection) { stmts; }
+
+/// Into:
+/// {
+///   type elem;
+///   struct __objcFastEnumerationState enumState = { 0 };
+///   id __rw_items[16];
+///   id l_collection = (id)collection;
+///   unsigned long limit = [l_collection countByEnumeratingWithState:&enumState
+///                                       objects:__rw_items count:16];
+/// if (limit) {
+///   unsigned long startMutations = *enumState.mutationsPtr;
+///   do {
+///        unsigned long counter = 0;
+///        do {
+///             if (startMutations != *enumState.mutationsPtr)
+///               objc_enumerationMutation(l_collection);
+///             elem = (type)enumState.itemsPtr[counter++];
+///             stmts;
+///             __continue_label: ;
+///        } while (counter < limit);
+///   } while (limit = [l_collection countByEnumeratingWithState:&enumState
+///                                  objects:__rw_items count:16]);
+///   elem = nil;
+///   __break_label: ;
+///  }
+///  else
+///       elem = nil;
+///  }
+///
+Stmt *RewriteObjC::RewriteObjCForCollectionStmt(ObjCForCollectionStmt *S,
+                                                SourceLocation OrigEnd) {
+  assert(!Stmts.empty() && "ObjCForCollectionStmt - Statement stack empty");
+  assert(isa<ObjCForCollectionStmt>(Stmts.back()) &&
+         "ObjCForCollectionStmt Statement stack mismatch");
+  assert(!ObjCBcLabelNo.empty() &&
+         "ObjCForCollectionStmt - Label No stack empty");
+
+  SourceLocation startLoc = S->getLocStart();
+  const char *startBuf = SM->getCharacterData(startLoc);
+  StringRef elementName;
+  std::string elementTypeAsString;
+  std::string buf;
+  buf = "\n{\n\t";
+  if (DeclStmt *DS = dyn_cast<DeclStmt>(S->getElement())) {
+    // type elem;
+    NamedDecl* D = cast<NamedDecl>(DS->getSingleDecl());
+    QualType ElementType = cast<ValueDecl>(D)->getType();
+    if (ElementType->isObjCQualifiedIdType() ||
+        ElementType->isObjCQualifiedInterfaceType())
+      // Simply use 'id' for all qualified types.
+      elementTypeAsString = "id";
+    else
+      elementTypeAsString = ElementType.getAsString(Context->getPrintingPolicy());
+    buf += elementTypeAsString;
+    buf += " ";
+    elementName = D->getName();
+    buf += elementName;
+    buf += ";\n\t";
+  }
+  else {
+    DeclRefExpr *DR = cast<DeclRefExpr>(S->getElement());
+    elementName = DR->getDecl()->getName();
+    ValueDecl *VD = cast<ValueDecl>(DR->getDecl());
+    if (VD->getType()->isObjCQualifiedIdType() ||
+        VD->getType()->isObjCQualifiedInterfaceType())
+      // Simply use 'id' for all qualified types.
+      elementTypeAsString = "id";
+    else
+      elementTypeAsString = VD->getType().getAsString(Context->getPrintingPolicy());
+  }
+
+  // struct __objcFastEnumerationState enumState = { 0 };
+  buf += "struct __objcFastEnumerationState enumState = { 0 };\n\t";
+  // id __rw_items[16];
+  buf += "id __rw_items[16];\n\t";
+  // id l_collection = (id)
+  buf += "id l_collection = (id)";
+  // Find start location of 'collection' the hard way!
+  const char *startCollectionBuf = startBuf;
+  startCollectionBuf += 3;  // skip 'for'
+  startCollectionBuf = strchr(startCollectionBuf, '(');
+  startCollectionBuf++; // skip '('
+  // find 'in' and skip it.
+  while (*startCollectionBuf != ' ' ||
+         *(startCollectionBuf+1) != 'i' || *(startCollectionBuf+2) != 'n' ||
+         (*(startCollectionBuf+3) != ' ' &&
+          *(startCollectionBuf+3) != '[' && *(startCollectionBuf+3) != '('))
+    startCollectionBuf++;
+  startCollectionBuf += 3;
+
+  // Replace: "for (type element in" with string constructed thus far.
+  ReplaceText(startLoc, startCollectionBuf - startBuf, buf);
+  // Replace ')' in for '(' type elem in collection ')' with ';'
+  SourceLocation rightParenLoc = S->getRParenLoc();
+  const char *rparenBuf = SM->getCharacterData(rightParenLoc);
+  SourceLocation lparenLoc = startLoc.getLocWithOffset(rparenBuf-startBuf);
+  buf = ";\n\t";
+
+  // unsigned long limit = [l_collection countByEnumeratingWithState:&enumState
+  //                                   objects:__rw_items count:16];
+  // which is synthesized into:
+  // unsigned int limit =
+  // ((unsigned int (*)
+  //  (id, SEL, struct __objcFastEnumerationState *, id *, unsigned int))
+  //  (void *)objc_msgSend)((id)l_collection,
+  //                        sel_registerName(
+  //                          "countByEnumeratingWithState:objects:count:"),
+  //                        (struct __objcFastEnumerationState *)&state,
+  //                        (id *)__rw_items, (unsigned int)16);
+  buf += "unsigned long limit =\n\t\t";
+  SynthCountByEnumWithState(buf);
+  buf += ";\n\t";
+  /// if (limit) {
+  ///   unsigned long startMutations = *enumState.mutationsPtr;
+  ///   do {
+  ///        unsigned long counter = 0;
+  ///        do {
+  ///             if (startMutations != *enumState.mutationsPtr)
+  ///               objc_enumerationMutation(l_collection);
+  ///             elem = (type)enumState.itemsPtr[counter++];
+  buf += "if (limit) {\n\t";
+  buf += "unsigned long startMutations = *enumState.mutationsPtr;\n\t";
+  buf += "do {\n\t\t";
+  buf += "unsigned long counter = 0;\n\t\t";
+  buf += "do {\n\t\t\t";
+  buf += "if (startMutations != *enumState.mutationsPtr)\n\t\t\t\t";
+  buf += "objc_enumerationMutation(l_collection);\n\t\t\t";
+  buf += elementName;
+  buf += " = (";
+  buf += elementTypeAsString;
+  buf += ")enumState.itemsPtr[counter++];";
+  // Replace ')' in for '(' type elem in collection ')' with all of these.
+  ReplaceText(lparenLoc, 1, buf);
+
+  ///            __continue_label: ;
+  ///        } while (counter < limit);
+  ///   } while (limit = [l_collection countByEnumeratingWithState:&enumState
+  ///                                  objects:__rw_items count:16]);
+  ///   elem = nil;
+  ///   __break_label: ;
+  ///  }
+  ///  else
+  ///       elem = nil;
+  ///  }
+  ///
+  buf = ";\n\t";
+  buf += "__continue_label_";
+  buf += utostr(ObjCBcLabelNo.back());
+  buf += ": ;";
+  buf += "\n\t\t";
+  buf += "} while (counter < limit);\n\t";
+  buf += "} while (limit = ";
+  SynthCountByEnumWithState(buf);
+  buf += ");\n\t";
+  buf += elementName;
+  buf += " = ((";
+  buf += elementTypeAsString;
+  buf += ")0);\n\t";
+  buf += "__break_label_";
+  buf += utostr(ObjCBcLabelNo.back());
+  buf += ": ;\n\t";
+  buf += "}\n\t";
+  buf += "else\n\t\t";
+  buf += elementName;
+  buf += " = ((";
+  buf += elementTypeAsString;
+  buf += ")0);\n\t";
+  buf += "}\n";
+
+  // Insert all these *after* the statement body.
+  // FIXME: If this should support Obj-C++, support CXXTryStmt
+  if (isa<CompoundStmt>(S->getBody())) {
+    SourceLocation endBodyLoc = OrigEnd.getLocWithOffset(1);
+    InsertText(endBodyLoc, buf);
+  } else {
+    /* Need to treat single statements specially. For example:
+     *
+     *     for (A *a in b) if (stuff()) break;
+     *     for (A *a in b) xxxyy;
+     *
+     * The following code simply scans ahead to the semi to find the actual end.
+     */
+    const char *stmtBuf = SM->getCharacterData(OrigEnd);
+    const char *semiBuf = strchr(stmtBuf, ';');
+    assert(semiBuf && "Can't find ';'");
+    SourceLocation endBodyLoc = OrigEnd.getLocWithOffset(semiBuf-stmtBuf+1);
+    InsertText(endBodyLoc, buf);
+  }
+  Stmts.pop_back();
+  ObjCBcLabelNo.pop_back();
+  return nullptr;
+}
+
+/// RewriteObjCSynchronizedStmt -
+/// This routine rewrites @synchronized(expr) stmt;
+/// into:
+/// objc_sync_enter(expr);
+/// @try stmt @finally { objc_sync_exit(expr); }
+///
+Stmt *RewriteObjC::RewriteObjCSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
+  // Get the start location and compute the semi location.
+  SourceLocation startLoc = S->getLocStart();
+  const char *startBuf = SM->getCharacterData(startLoc);
+
+  assert((*startBuf == '@') && "bogus @synchronized location");
+
+  std::string buf;
+  buf = "objc_sync_enter((id)";
+  const char *lparenBuf = startBuf;
+  while (*lparenBuf != '(') lparenBuf++;
+  ReplaceText(startLoc, lparenBuf-startBuf+1, buf);
+  // We can't use S->getSynchExpr()->getLocEnd() to find the end location, since
+  // the sync expression is typically a message expression that's already
+  // been rewritten! (which implies the SourceLocation's are invalid).
+  SourceLocation endLoc = S->getSynchBody()->getLocStart();
+  const char *endBuf = SM->getCharacterData(endLoc);
+  while (*endBuf != ')') endBuf--;
+  SourceLocation rparenLoc = startLoc.getLocWithOffset(endBuf-startBuf);
+  buf = ");\n";
+  // declare a new scope with two variables, _stack and _rethrow.
+  buf += "/* @try scope begin */ \n{ struct _objc_exception_data {\n";
+  buf += "int buf[18/*32-bit i386*/];\n";
+  buf += "char *pointers[4];} _stack;\n";
+  buf += "id volatile _rethrow = 0;\n";
+  buf += "objc_exception_try_enter(&_stack);\n";
+  buf += "if (!_setjmp(_stack.buf)) /* @try block continue */\n";
+  ReplaceText(rparenLoc, 1, buf);
+  startLoc = S->getSynchBody()->getLocEnd();
+  startBuf = SM->getCharacterData(startLoc);
+
+  assert((*startBuf == '}') && "bogus @synchronized block");
+  SourceLocation lastCurlyLoc = startLoc;
+  buf = "}\nelse {\n";
+  buf += "  _rethrow = objc_exception_extract(&_stack);\n";
+  buf += "}\n";
+  buf += "{ /* implicit finally clause */\n";
+  buf += "  if (!_rethrow) objc_exception_try_exit(&_stack);\n";
+  
+  std::string syncBuf;
+  syncBuf += " objc_sync_exit(";
+
+  Expr *syncExpr = S->getSynchExpr();
+  CastKind CK = syncExpr->getType()->isObjCObjectPointerType()
+                  ? CK_BitCast :
+                syncExpr->getType()->isBlockPointerType()
+                  ? CK_BlockPointerToObjCPointerCast
+                  : CK_CPointerToObjCPointerCast;
+  syncExpr = NoTypeInfoCStyleCastExpr(Context, Context->getObjCIdType(),
+                                      CK, syncExpr);
+  std::string syncExprBufS;
+  llvm::raw_string_ostream syncExprBuf(syncExprBufS);
+  assert(syncExpr != nullptr && "Expected non-null Expr");
+  syncExpr->printPretty(syncExprBuf, nullptr, PrintingPolicy(LangOpts));
+  syncBuf += syncExprBuf.str();
+  syncBuf += ");";
+  
+  buf += syncBuf;
+  buf += "\n  if (_rethrow) objc_exception_throw(_rethrow);\n";
+  buf += "}\n";
+  buf += "}";
+
+  ReplaceText(lastCurlyLoc, 1, buf);
+
+  bool hasReturns = false;
+  HasReturnStmts(S->getSynchBody(), hasReturns);
+  if (hasReturns)
+    RewriteSyncReturnStmts(S->getSynchBody(), syncBuf);
+
+  return nullptr;
+}
+
+void RewriteObjC::WarnAboutReturnGotoStmts(Stmt *S)
+{
+  // Perform a bottom up traversal of all children.
+  for (Stmt::child_range CI = S->children(); CI; ++CI)
+    if (*CI)
+      WarnAboutReturnGotoStmts(*CI);
+
+  if (isa<ReturnStmt>(S) || isa<GotoStmt>(S)) {
+    Diags.Report(Context->getFullLoc(S->getLocStart()),
+                 TryFinallyContainsReturnDiag);
+  }
+  return;
+}
+
+void RewriteObjC::HasReturnStmts(Stmt *S, bool &hasReturns) 
+{  
+  // Perform a bottom up traversal of all children.
+  for (Stmt::child_range CI = S->children(); CI; ++CI)
+   if (*CI)
+     HasReturnStmts(*CI, hasReturns);
+
+ if (isa<ReturnStmt>(S))
+   hasReturns = true;
+ return;
+}
+
+void RewriteObjC::RewriteTryReturnStmts(Stmt *S) {
+ // Perform a bottom up traversal of all children.
+ for (Stmt::child_range CI = S->children(); CI; ++CI)
+   if (*CI) {
+     RewriteTryReturnStmts(*CI);
+   }
+ if (isa<ReturnStmt>(S)) {
+   SourceLocation startLoc = S->getLocStart();
+   const char *startBuf = SM->getCharacterData(startLoc);
+
+   const char *semiBuf = strchr(startBuf, ';');
+   assert((*semiBuf == ';') && "RewriteTryReturnStmts: can't find ';'");
+   SourceLocation onePastSemiLoc = startLoc.getLocWithOffset(semiBuf-startBuf+1);
+
+   std::string buf;
+   buf = "{ objc_exception_try_exit(&_stack); return";
+   
+   ReplaceText(startLoc, 6, buf);
+   InsertText(onePastSemiLoc, "}");
+ }
+ return;
+}
+
+void RewriteObjC::RewriteSyncReturnStmts(Stmt *S, std::string syncExitBuf) {
+  // Perform a bottom up traversal of all children.
+  for (Stmt::child_range CI = S->children(); CI; ++CI)
+    if (*CI) {
+      RewriteSyncReturnStmts(*CI, syncExitBuf);
+    }
+  if (isa<ReturnStmt>(S)) {
+    SourceLocation startLoc = S->getLocStart();
+    const char *startBuf = SM->getCharacterData(startLoc);
+
+    const char *semiBuf = strchr(startBuf, ';');
+    assert((*semiBuf == ';') && "RewriteSyncReturnStmts: can't find ';'");
+    SourceLocation onePastSemiLoc = startLoc.getLocWithOffset(semiBuf-startBuf+1);
+
+    std::string buf;
+    buf = "{ objc_exception_try_exit(&_stack);";
+    buf += syncExitBuf;
+    buf += " return";
+    
+    ReplaceText(startLoc, 6, buf);
+    InsertText(onePastSemiLoc, "}");
+  }
+  return;
+}
+
+Stmt *RewriteObjC::RewriteObjCTryStmt(ObjCAtTryStmt *S) {
+  // Get the start location and compute the semi location.
+  SourceLocation startLoc = S->getLocStart();
+  const char *startBuf = SM->getCharacterData(startLoc);
+
+  assert((*startBuf == '@') && "bogus @try location");
+
+  std::string buf;
+  // declare a new scope with two variables, _stack and _rethrow.
+  buf = "/* @try scope begin */ { struct _objc_exception_data {\n";
+  buf += "int buf[18/*32-bit i386*/];\n";
+  buf += "char *pointers[4];} _stack;\n";
+  buf += "id volatile _rethrow = 0;\n";
+  buf += "objc_exception_try_enter(&_stack);\n";
+  buf += "if (!_setjmp(_stack.buf)) /* @try block continue */\n";
+
+  ReplaceText(startLoc, 4, buf);
+
+  startLoc = S->getTryBody()->getLocEnd();
+  startBuf = SM->getCharacterData(startLoc);
+
+  assert((*startBuf == '}') && "bogus @try block");
+
+  SourceLocation lastCurlyLoc = startLoc;
+  if (S->getNumCatchStmts()) {
+    startLoc = startLoc.getLocWithOffset(1);
+    buf = " /* @catch begin */ else {\n";
+    buf += " id _caught = objc_exception_extract(&_stack);\n";
+    buf += " objc_exception_try_enter (&_stack);\n";
+    buf += " if (_setjmp(_stack.buf))\n";
+    buf += "   _rethrow = objc_exception_extract(&_stack);\n";
+    buf += " else { /* @catch continue */";
+
+    InsertText(startLoc, buf);
+  } else { /* no catch list */
+    buf = "}\nelse {\n";
+    buf += "  _rethrow = objc_exception_extract(&_stack);\n";
+    buf += "}";
+    ReplaceText(lastCurlyLoc, 1, buf);
+  }
+  Stmt *lastCatchBody = nullptr;
+  for (unsigned I = 0, N = S->getNumCatchStmts(); I != N; ++I) {
+    ObjCAtCatchStmt *Catch = S->getCatchStmt(I);
+    VarDecl *catchDecl = Catch->getCatchParamDecl();
+
+    if (I == 0)
+      buf = "if ("; // we are generating code for the first catch clause
+    else
+      buf = "else if (";
+    startLoc = Catch->getLocStart();
+    startBuf = SM->getCharacterData(startLoc);
+
+    assert((*startBuf == '@') && "bogus @catch location");
+
+    const char *lParenLoc = strchr(startBuf, '(');
+
+    if (Catch->hasEllipsis()) {
+      // Now rewrite the body...
+      lastCatchBody = Catch->getCatchBody();
+      SourceLocation bodyLoc = lastCatchBody->getLocStart();
+      const char *bodyBuf = SM->getCharacterData(bodyLoc);
+      assert(*SM->getCharacterData(Catch->getRParenLoc()) == ')' &&
+             "bogus @catch paren location");
+      assert((*bodyBuf == '{') && "bogus @catch body location");
+
+      buf += "1) { id _tmp = _caught;";
+      Rewrite.ReplaceText(startLoc, bodyBuf-startBuf+1, buf);
+    } else if (catchDecl) {
+      QualType t = catchDecl->getType();
+      if (t == Context->getObjCIdType()) {
+        buf += "1) { ";
+        ReplaceText(startLoc, lParenLoc-startBuf+1, buf);
+      } else if (const ObjCObjectPointerType *Ptr =
+                   t->getAs<ObjCObjectPointerType>()) {
+        // Should be a pointer to a class.
+        ObjCInterfaceDecl *IDecl = Ptr->getObjectType()->getInterface();
+        if (IDecl) {
+          buf += "objc_exception_match((struct objc_class *)objc_getClass(\"";
+          buf += IDecl->getNameAsString();
+          buf += "\"), (struct objc_object *)_caught)) { ";
+          ReplaceText(startLoc, lParenLoc-startBuf+1, buf);
+        }
+      }
+      // Now rewrite the body...
+      lastCatchBody = Catch->getCatchBody();
+      SourceLocation rParenLoc = Catch->getRParenLoc();
+      SourceLocation bodyLoc = lastCatchBody->getLocStart();
+      const char *bodyBuf = SM->getCharacterData(bodyLoc);
+      const char *rParenBuf = SM->getCharacterData(rParenLoc);
+      assert((*rParenBuf == ')') && "bogus @catch paren location");
+      assert((*bodyBuf == '{') && "bogus @catch body location");
+
+      // Here we replace ") {" with "= _caught;" (which initializes and
+      // declares the @catch parameter).
+      ReplaceText(rParenLoc, bodyBuf-rParenBuf+1, " = _caught;");
+    } else {
+      llvm_unreachable("@catch rewrite bug");
+    }
+  }
+  // Complete the catch list...
+  if (lastCatchBody) {
+    SourceLocation bodyLoc = lastCatchBody->getLocEnd();
+    assert(*SM->getCharacterData(bodyLoc) == '}' &&
+           "bogus @catch body location");
+
+    // Insert the last (implicit) else clause *before* the right curly brace.
+    bodyLoc = bodyLoc.getLocWithOffset(-1);
+    buf = "} /* last catch end */\n";
+    buf += "else {\n";
+    buf += " _rethrow = _caught;\n";
+    buf += " objc_exception_try_exit(&_stack);\n";
+    buf += "} } /* @catch end */\n";
+    if (!S->getFinallyStmt())
+      buf += "}\n";
+    InsertText(bodyLoc, buf);
+
+    // Set lastCurlyLoc
+    lastCurlyLoc = lastCatchBody->getLocEnd();
+  }
+  if (ObjCAtFinallyStmt *finalStmt = S->getFinallyStmt()) {
+    startLoc = finalStmt->getLocStart();
+    startBuf = SM->getCharacterData(startLoc);
+    assert((*startBuf == '@') && "bogus @finally start");
+
+    ReplaceText(startLoc, 8, "/* @finally */");
+
+    Stmt *body = finalStmt->getFinallyBody();
+    SourceLocation startLoc = body->getLocStart();
+    SourceLocation endLoc = body->getLocEnd();
+    assert(*SM->getCharacterData(startLoc) == '{' &&
+           "bogus @finally body location");
+    assert(*SM->getCharacterData(endLoc) == '}' &&
+           "bogus @finally body location");
+
+    startLoc = startLoc.getLocWithOffset(1);
+    InsertText(startLoc, " if (!_rethrow) objc_exception_try_exit(&_stack);\n");
+    endLoc = endLoc.getLocWithOffset(-1);
+    InsertText(endLoc, " if (_rethrow) objc_exception_throw(_rethrow);\n");
+
+    // Set lastCurlyLoc
+    lastCurlyLoc = body->getLocEnd();
+
+    // Now check for any return/continue/go statements within the @try.
+    WarnAboutReturnGotoStmts(S->getTryBody());
+  } else { /* no finally clause - make sure we synthesize an implicit one */
+    buf = "{ /* implicit finally clause */\n";
+    buf += " if (!_rethrow) objc_exception_try_exit(&_stack);\n";
+    buf += " if (_rethrow) objc_exception_throw(_rethrow);\n";
+    buf += "}";
+    ReplaceText(lastCurlyLoc, 1, buf);
+    
+    // Now check for any return/continue/go statements within the @try.
+    // The implicit finally clause won't called if the @try contains any
+    // jump statements.
+    bool hasReturns = false;
+    HasReturnStmts(S->getTryBody(), hasReturns);
+    if (hasReturns)
+      RewriteTryReturnStmts(S->getTryBody());
+  }
+  // Now emit the final closing curly brace...
+  lastCurlyLoc = lastCurlyLoc.getLocWithOffset(1);
+  InsertText(lastCurlyLoc, " } /* @try scope end */\n");
+  return nullptr;
+}
+
+// This can't be done with ReplaceStmt(S, ThrowExpr), since
+// the throw expression is typically a message expression that's already
+// been rewritten! (which implies the SourceLocation's are invalid).
+Stmt *RewriteObjC::RewriteObjCThrowStmt(ObjCAtThrowStmt *S) {
+  // Get the start location and compute the semi location.
+  SourceLocation startLoc = S->getLocStart();
+  const char *startBuf = SM->getCharacterData(startLoc);
+
+  assert((*startBuf == '@') && "bogus @throw location");
+
+  std::string buf;
+  /* void objc_exception_throw(id) __attribute__((noreturn)); */
+  if (S->getThrowExpr())
+    buf = "objc_exception_throw(";
+  else // add an implicit argument
+    buf = "objc_exception_throw(_caught";
+
+  // handle "@  throw" correctly.
+  const char *wBuf = strchr(startBuf, 'w');
+  assert((*wBuf == 'w') && "@throw: can't find 'w'");
+  ReplaceText(startLoc, wBuf-startBuf+1, buf);
+
+  const char *semiBuf = strchr(startBuf, ';');
+  assert((*semiBuf == ';') && "@throw: can't find ';'");
+  SourceLocation semiLoc = startLoc.getLocWithOffset(semiBuf-startBuf);
+  ReplaceText(semiLoc, 1, ");");
+  return nullptr;
+}
+
+Stmt *RewriteObjC::RewriteAtEncode(ObjCEncodeExpr *Exp) {
+  // Create a new string expression.
+  std::string StrEncoding;
+  Context->getObjCEncodingForType(Exp->getEncodedType(), StrEncoding);
+  Expr *Replacement = getStringLiteral(StrEncoding);
+  ReplaceStmt(Exp, Replacement);
+
+  // Replace this subexpr in the parent.
+  // delete Exp; leak for now, see RewritePropertyOrImplicitSetter() usage for more info.
+  return Replacement;
+}
+
+Stmt *RewriteObjC::RewriteAtSelector(ObjCSelectorExpr *Exp) {
+  if (!SelGetUidFunctionDecl)
+    SynthSelGetUidFunctionDecl();
+  assert(SelGetUidFunctionDecl && "Can't find sel_registerName() decl");
+  // Create a call to sel_registerName("selName").
+  SmallVector<Expr*, 8> SelExprs;
+  SelExprs.push_back(getStringLiteral(Exp->getSelector().getAsString()));
+  CallExpr *SelExp = SynthesizeCallToFunctionDecl(SelGetUidFunctionDecl,
+                                                 &SelExprs[0], SelExprs.size());
+  ReplaceStmt(Exp, SelExp);
+  // delete Exp; leak for now, see RewritePropertyOrImplicitSetter() usage for more info.
+  return SelExp;
+}
+
+CallExpr *RewriteObjC::SynthesizeCallToFunctionDecl(
+  FunctionDecl *FD, Expr **args, unsigned nargs, SourceLocation StartLoc,
+                                                    SourceLocation EndLoc) {
+  // Get the type, we will need to reference it in a couple spots.
+  QualType msgSendType = FD->getType();
+
+  // Create a reference to the objc_msgSend() declaration.
+  DeclRefExpr *DRE = new (Context) DeclRefExpr(FD, false, msgSendType,
+                                               VK_LValue, SourceLocation());
+
+  // Now, we cast the reference to a pointer to the objc_msgSend type.
+  QualType pToFunc = Context->getPointerType(msgSendType);
+  ImplicitCastExpr *ICE =
+    ImplicitCastExpr::Create(*Context, pToFunc, CK_FunctionToPointerDecay,
+                             DRE, nullptr, VK_RValue);
+
+  const FunctionType *FT = msgSendType->getAs<FunctionType>();
+
+  CallExpr *Exp =  
+    new (Context) CallExpr(*Context, ICE, llvm::makeArrayRef(args, nargs),
+                           FT->getCallResultType(*Context),
+                           VK_RValue, EndLoc);
+  return Exp;
+}
+
+static bool scanForProtocolRefs(const char *startBuf, const char *endBuf,
+                                const char *&startRef, const char *&endRef) {
+  while (startBuf < endBuf) {
+    if (*startBuf == '<')
+      startRef = startBuf; // mark the start.
+    if (*startBuf == '>') {
+      if (startRef && *startRef == '<') {
+        endRef = startBuf; // mark the end.
+        return true;
+      }
+      return false;
+    }
+    startBuf++;
+  }
+  return false;
+}
+
+static void scanToNextArgument(const char *&argRef) {
+  int angle = 0;
+  while (*argRef != ')' && (*argRef != ',' || angle > 0)) {
+    if (*argRef == '<')
+      angle++;
+    else if (*argRef == '>')
+      angle--;
+    argRef++;
+  }
+  assert(angle == 0 && "scanToNextArgument - bad protocol type syntax");
+}
+
+bool RewriteObjC::needToScanForQualifiers(QualType T) {
+  if (T->isObjCQualifiedIdType())
+    return true;
+  if (const PointerType *PT = T->getAs<PointerType>()) {
+    if (PT->getPointeeType()->isObjCQualifiedIdType())
+      return true;
+  }
+  if (T->isObjCObjectPointerType()) {
+    T = T->getPointeeType();
+    return T->isObjCQualifiedInterfaceType();
+  }
+  if (T->isArrayType()) {
+    QualType ElemTy = Context->getBaseElementType(T);
+    return needToScanForQualifiers(ElemTy);
+  }
+  return false;
+}
+
+void RewriteObjC::RewriteObjCQualifiedInterfaceTypes(Expr *E) {
+  QualType Type = E->getType();
+  if (needToScanForQualifiers(Type)) {
+    SourceLocation Loc, EndLoc;
+
+    if (const CStyleCastExpr *ECE = dyn_cast<CStyleCastExpr>(E)) {
+      Loc = ECE->getLParenLoc();
+      EndLoc = ECE->getRParenLoc();
+    } else {
+      Loc = E->getLocStart();
+      EndLoc = E->getLocEnd();
+    }
+    // This will defend against trying to rewrite synthesized expressions.
+    if (Loc.isInvalid() || EndLoc.isInvalid())
+      return;
+
+    const char *startBuf = SM->getCharacterData(Loc);
+    const char *endBuf = SM->getCharacterData(EndLoc);
+    const char *startRef = nullptr, *endRef = nullptr;
+    if (scanForProtocolRefs(startBuf, endBuf, startRef, endRef)) {
+      // Get the locations of the startRef, endRef.
+      SourceLocation LessLoc = Loc.getLocWithOffset(startRef-startBuf);
+      SourceLocation GreaterLoc = Loc.getLocWithOffset(endRef-startBuf+1);
+      // Comment out the protocol references.
+      InsertText(LessLoc, "/*");
+      InsertText(GreaterLoc, "*/");
+    }
+  }
+}
+
+void RewriteObjC::RewriteObjCQualifiedInterfaceTypes(Decl *Dcl) {
+  SourceLocation Loc;
+  QualType Type;
+  const FunctionProtoType *proto = nullptr;
+  if (VarDecl *VD = dyn_cast<VarDecl>(Dcl)) {
+    Loc = VD->getLocation();
+    Type = VD->getType();
+  }
+  else if (FunctionDecl *FD = dyn_cast<FunctionDecl>(Dcl)) {
+    Loc = FD->getLocation();
+    // Check for ObjC 'id' and class types that have been adorned with protocol
+    // information (id<p>, C<p>*). The protocol references need to be rewritten!
+    const FunctionType *funcType = FD->getType()->getAs<FunctionType>();
+    assert(funcType && "missing function type");
+    proto = dyn_cast<FunctionProtoType>(funcType);
+    if (!proto)
+      return;
+    Type = proto->getReturnType();
+  }
+  else if (FieldDecl *FD = dyn_cast<FieldDecl>(Dcl)) {
+    Loc = FD->getLocation();
+    Type = FD->getType();
+  }
+  else
+    return;
+
+  if (needToScanForQualifiers(Type)) {
+    // Since types are unique, we need to scan the buffer.
+
+    const char *endBuf = SM->getCharacterData(Loc);
+    const char *startBuf = endBuf;
+    while (*startBuf != ';' && *startBuf != '<' && startBuf != MainFileStart)
+      startBuf--; // scan backward (from the decl location) for return type.
+    const char *startRef = nullptr, *endRef = nullptr;
+    if (scanForProtocolRefs(startBuf, endBuf, startRef, endRef)) {
+      // Get the locations of the startRef, endRef.
+      SourceLocation LessLoc = Loc.getLocWithOffset(startRef-endBuf);
+      SourceLocation GreaterLoc = Loc.getLocWithOffset(endRef-endBuf+1);
+      // Comment out the protocol references.
+      InsertText(LessLoc, "/*");
+      InsertText(GreaterLoc, "*/");
+    }
+  }
+  if (!proto)
+      return; // most likely, was a variable
+  // Now check arguments.
+  const char *startBuf = SM->getCharacterData(Loc);
+  const char *startFuncBuf = startBuf;
+  for (unsigned i = 0; i < proto->getNumParams(); i++) {
+    if (needToScanForQualifiers(proto->getParamType(i))) {
+      // Since types are unique, we need to scan the buffer.
+
+      const char *endBuf = startBuf;
+      // scan forward (from the decl location) for argument types.
+      scanToNextArgument(endBuf);
+      const char *startRef = nullptr, *endRef = nullptr;
+      if (scanForProtocolRefs(startBuf, endBuf, startRef, endRef)) {
+        // Get the locations of the startRef, endRef.
+        SourceLocation LessLoc =
+          Loc.getLocWithOffset(startRef-startFuncBuf);
+        SourceLocation GreaterLoc =
+          Loc.getLocWithOffset(endRef-startFuncBuf+1);
+        // Comment out the protocol references.
+        InsertText(LessLoc, "/*");
+        InsertText(GreaterLoc, "*/");
+      }
+      startBuf = ++endBuf;
+    }
+    else {
+      // If the function name is derived from a macro expansion, then the
+      // argument buffer will not follow the name. Need to speak with Chris.
+      while (*startBuf && *startBuf != ')' && *startBuf != ',')
+        startBuf++; // scan forward (from the decl location) for argument types.
+      startBuf++;
+    }
+  }
+}
+
+void RewriteObjC::RewriteTypeOfDecl(VarDecl *ND) {
+  QualType QT = ND->getType();
+  const Type* TypePtr = QT->getAs<Type>();
+  if (!isa<TypeOfExprType>(TypePtr))
+    return;
+  while (isa<TypeOfExprType>(TypePtr)) {
+    const TypeOfExprType *TypeOfExprTypePtr = cast<TypeOfExprType>(TypePtr);
+    QT = TypeOfExprTypePtr->getUnderlyingExpr()->getType();
+    TypePtr = QT->getAs<Type>();
+  }
+  // FIXME. This will not work for multiple declarators; as in:
+  // __typeof__(a) b,c,d;
+  std::string TypeAsString(QT.getAsString(Context->getPrintingPolicy()));
+  SourceLocation DeclLoc = ND->getTypeSpecStartLoc();
+  const char *startBuf = SM->getCharacterData(DeclLoc);
+  if (ND->getInit()) {
+    std::string Name(ND->getNameAsString());
+    TypeAsString += " " + Name + " = ";
+    Expr *E = ND->getInit();
+    SourceLocation startLoc;
+    if (const CStyleCastExpr *ECE = dyn_cast<CStyleCastExpr>(E))
+      startLoc = ECE->getLParenLoc();
+    else
+      startLoc = E->getLocStart();
+    startLoc = SM->getExpansionLoc(startLoc);
+    const char *endBuf = SM->getCharacterData(startLoc);
+    ReplaceText(DeclLoc, endBuf-startBuf-1, TypeAsString);
+  }
+  else {
+    SourceLocation X = ND->getLocEnd();
+    X = SM->getExpansionLoc(X);
+    const char *endBuf = SM->getCharacterData(X);
+    ReplaceText(DeclLoc, endBuf-startBuf-1, TypeAsString);
+  }
+}
+
+// SynthSelGetUidFunctionDecl - SEL sel_registerName(const char *str);
+void RewriteObjC::SynthSelGetUidFunctionDecl() {
+  IdentifierInfo *SelGetUidIdent = &Context->Idents.get("sel_registerName");
+  SmallVector<QualType, 16> ArgTys;
+  ArgTys.push_back(Context->getPointerType(Context->CharTy.withConst()));
+  QualType getFuncType =
+    getSimpleFunctionType(Context->getObjCSelType(), ArgTys);
+  SelGetUidFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                               SourceLocation(),
+                                               SourceLocation(),
+                                               SelGetUidIdent, getFuncType,
+                                               nullptr, SC_Extern);
+}
+
+void RewriteObjC::RewriteFunctionDecl(FunctionDecl *FD) {
+  // declared in <objc/objc.h>
+  if (FD->getIdentifier() &&
+      FD->getName() == "sel_registerName") {
+    SelGetUidFunctionDecl = FD;
+    return;
+  }
+  RewriteObjCQualifiedInterfaceTypes(FD);
+}
+
+void RewriteObjC::RewriteBlockPointerType(std::string& Str, QualType Type) {
+  std::string TypeString(Type.getAsString(Context->getPrintingPolicy()));
+  const char *argPtr = TypeString.c_str();
+  if (!strchr(argPtr, '^')) {
+    Str += TypeString;
+    return;
+  }
+  while (*argPtr) {
+    Str += (*argPtr == '^' ? '*' : *argPtr);
+    argPtr++;
+  }
+}
+
+// FIXME. Consolidate this routine with RewriteBlockPointerType.
+void RewriteObjC::RewriteBlockPointerTypeVariable(std::string& Str,
+                                                  ValueDecl *VD) {
+  QualType Type = VD->getType();
+  std::string TypeString(Type.getAsString(Context->getPrintingPolicy()));
+  const char *argPtr = TypeString.c_str();
+  int paren = 0;
+  while (*argPtr) {
+    switch (*argPtr) {
+      case '(':
+        Str += *argPtr;
+        paren++;
+        break;
+      case ')':
+        Str += *argPtr;
+        paren--;
+        break;
+      case '^':
+        Str += '*';
+        if (paren == 1)
+          Str += VD->getNameAsString();
+        break;
+      default:
+        Str += *argPtr;
+        break;
+    }
+    argPtr++;
+  }
+}
+
+
+void RewriteObjC::RewriteBlockLiteralFunctionDecl(FunctionDecl *FD) {
+  SourceLocation FunLocStart = FD->getTypeSpecStartLoc();
+  const FunctionType *funcType = FD->getType()->getAs<FunctionType>();
+  const FunctionProtoType *proto = dyn_cast<FunctionProtoType>(funcType);
+  if (!proto)
+    return;
+  QualType Type = proto->getReturnType();
+  std::string FdStr = Type.getAsString(Context->getPrintingPolicy());
+  FdStr += " ";
+  FdStr += FD->getName();
+  FdStr +=  "(";
+  unsigned numArgs = proto->getNumParams();
+  for (unsigned i = 0; i < numArgs; i++) {
+    QualType ArgType = proto->getParamType(i);
+    RewriteBlockPointerType(FdStr, ArgType);
+    if (i+1 < numArgs)
+      FdStr += ", ";
+  }
+  FdStr +=  ");\n";
+  InsertText(FunLocStart, FdStr);
+  CurFunctionDeclToDeclareForBlock = nullptr;
+}
+
+// SynthSuperConstructorFunctionDecl - id objc_super(id obj, id super);
+void RewriteObjC::SynthSuperConstructorFunctionDecl() {
+  if (SuperConstructorFunctionDecl)
+    return;
+  IdentifierInfo *msgSendIdent = &Context->Idents.get("__rw_objc_super");
+  SmallVector<QualType, 16> ArgTys;
+  QualType argT = Context->getObjCIdType();
+  assert(!argT.isNull() && "Can't find 'id' type");
+  ArgTys.push_back(argT);
+  ArgTys.push_back(argT);
+  QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
+                                               ArgTys);
+  SuperConstructorFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                                     SourceLocation(),
+                                                     SourceLocation(),
+                                                     msgSendIdent, msgSendType,
+                                                     nullptr, SC_Extern);
+}
+
+// SynthMsgSendFunctionDecl - id objc_msgSend(id self, SEL op, ...);
+void RewriteObjC::SynthMsgSendFunctionDecl() {
+  IdentifierInfo *msgSendIdent = &Context->Idents.get("objc_msgSend");
+  SmallVector<QualType, 16> ArgTys;
+  QualType argT = Context->getObjCIdType();
+  assert(!argT.isNull() && "Can't find 'id' type");
+  ArgTys.push_back(argT);
+  argT = Context->getObjCSelType();
+  assert(!argT.isNull() && "Can't find 'SEL' type");
+  ArgTys.push_back(argT);
+  QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
+                                               ArgTys, /*isVariadic=*/true);
+  MsgSendFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                             SourceLocation(),
+                                             SourceLocation(),
+                                             msgSendIdent, msgSendType,
+                                             nullptr, SC_Extern);
+}
+
+// SynthMsgSendSuperFunctionDecl - id objc_msgSendSuper(struct objc_super *, SEL op, ...);
+void RewriteObjC::SynthMsgSendSuperFunctionDecl() {
+  IdentifierInfo *msgSendIdent = &Context->Idents.get("objc_msgSendSuper");
+  SmallVector<QualType, 16> ArgTys;
+  RecordDecl *RD = RecordDecl::Create(*Context, TTK_Struct, TUDecl,
+                                      SourceLocation(), SourceLocation(),
+                                      &Context->Idents.get("objc_super"));
+  QualType argT = Context->getPointerType(Context->getTagDeclType(RD));
+  assert(!argT.isNull() && "Can't build 'struct objc_super *' type");
+  ArgTys.push_back(argT);
+  argT = Context->getObjCSelType();
+  assert(!argT.isNull() && "Can't find 'SEL' type");
+  ArgTys.push_back(argT);
+  QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
+                                               ArgTys, /*isVariadic=*/true);
+  MsgSendSuperFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                                  SourceLocation(),
+                                                  SourceLocation(),
+                                                  msgSendIdent, msgSendType,
+                                                  nullptr, SC_Extern);
+}
+
+// SynthMsgSendStretFunctionDecl - id objc_msgSend_stret(id self, SEL op, ...);
+void RewriteObjC::SynthMsgSendStretFunctionDecl() {
+  IdentifierInfo *msgSendIdent = &Context->Idents.get("objc_msgSend_stret");
+  SmallVector<QualType, 16> ArgTys;
+  QualType argT = Context->getObjCIdType();
+  assert(!argT.isNull() && "Can't find 'id' type");
+  ArgTys.push_back(argT);
+  argT = Context->getObjCSelType();
+  assert(!argT.isNull() && "Can't find 'SEL' type");
+  ArgTys.push_back(argT);
+  QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
+                                               ArgTys, /*isVariadic=*/true);
+  MsgSendStretFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                                  SourceLocation(),
+                                                  SourceLocation(),
+                                                  msgSendIdent, msgSendType,
+                                                  nullptr, SC_Extern);
+}
+
+// SynthMsgSendSuperStretFunctionDecl -
+// id objc_msgSendSuper_stret(struct objc_super *, SEL op, ...);
+void RewriteObjC::SynthMsgSendSuperStretFunctionDecl() {
+  IdentifierInfo *msgSendIdent =
+    &Context->Idents.get("objc_msgSendSuper_stret");
+  SmallVector<QualType, 16> ArgTys;
+  RecordDecl *RD = RecordDecl::Create(*Context, TTK_Struct, TUDecl,
+                                      SourceLocation(), SourceLocation(),
+                                      &Context->Idents.get("objc_super"));
+  QualType argT = Context->getPointerType(Context->getTagDeclType(RD));
+  assert(!argT.isNull() && "Can't build 'struct objc_super *' type");
+  ArgTys.push_back(argT);
+  argT = Context->getObjCSelType();
+  assert(!argT.isNull() && "Can't find 'SEL' type");
+  ArgTys.push_back(argT);
+  QualType msgSendType = getSimpleFunctionType(Context->getObjCIdType(),
+                                               ArgTys, /*isVariadic=*/true);
+  MsgSendSuperStretFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                                       SourceLocation(),
+                                                       SourceLocation(),
+                                                       msgSendIdent,
+                                                       msgSendType, nullptr,
+                                                       SC_Extern);
+}
+
+// SynthMsgSendFpretFunctionDecl - double objc_msgSend_fpret(id self, SEL op, ...);
+void RewriteObjC::SynthMsgSendFpretFunctionDecl() {
+  IdentifierInfo *msgSendIdent = &Context->Idents.get("objc_msgSend_fpret");
+  SmallVector<QualType, 16> ArgTys;
+  QualType argT = Context->getObjCIdType();
+  assert(!argT.isNull() && "Can't find 'id' type");
+  ArgTys.push_back(argT);
+  argT = Context->getObjCSelType();
+  assert(!argT.isNull() && "Can't find 'SEL' type");
+  ArgTys.push_back(argT);
+  QualType msgSendType = getSimpleFunctionType(Context->DoubleTy,
+                                               ArgTys, /*isVariadic=*/true);
+  MsgSendFpretFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                                  SourceLocation(),
+                                                  SourceLocation(),
+                                                  msgSendIdent, msgSendType,
+                                                  nullptr, SC_Extern);
+}
+
+// SynthGetClassFunctionDecl - id objc_getClass(const char *name);
+void RewriteObjC::SynthGetClassFunctionDecl() {
+  IdentifierInfo *getClassIdent = &Context->Idents.get("objc_getClass");
+  SmallVector<QualType, 16> ArgTys;
+  ArgTys.push_back(Context->getPointerType(Context->CharTy.withConst()));
+  QualType getClassType = getSimpleFunctionType(Context->getObjCIdType(),
+                                                ArgTys);
+  GetClassFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                              SourceLocation(),
+                                              SourceLocation(),
+                                              getClassIdent, getClassType,
+                                              nullptr, SC_Extern);
+}
+
+// SynthGetSuperClassFunctionDecl - Class class_getSuperclass(Class cls);
+void RewriteObjC::SynthGetSuperClassFunctionDecl() {
+  IdentifierInfo *getSuperClassIdent = 
+    &Context->Idents.get("class_getSuperclass");
+  SmallVector<QualType, 16> ArgTys;
+  ArgTys.push_back(Context->getObjCClassType());
+  QualType getClassType = getSimpleFunctionType(Context->getObjCClassType(),
+                                                ArgTys);
+  GetSuperClassFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                                   SourceLocation(),
+                                                   SourceLocation(),
+                                                   getSuperClassIdent,
+                                                   getClassType, nullptr,
+                                                   SC_Extern);
+}
+
+// SynthGetMetaClassFunctionDecl - id objc_getMetaClass(const char *name);
+void RewriteObjC::SynthGetMetaClassFunctionDecl() {
+  IdentifierInfo *getClassIdent = &Context->Idents.get("objc_getMetaClass");
+  SmallVector<QualType, 16> ArgTys;
+  ArgTys.push_back(Context->getPointerType(Context->CharTy.withConst()));
+  QualType getClassType = getSimpleFunctionType(Context->getObjCIdType(),
+                                                ArgTys);
+  GetMetaClassFunctionDecl = FunctionDecl::Create(*Context, TUDecl,
+                                                  SourceLocation(),
+                                                  SourceLocation(),
+                                                  getClassIdent, getClassType,
+                                                  nullptr, SC_Extern);
+}
+
+Stmt *RewriteObjC::RewriteObjCStringLiteral(ObjCStringLiteral *Exp) {
+  assert(Exp != nullptr && "Expected non-null ObjCStringLiteral");
+  QualType strType = getConstantStringStructType();
+
+  std::string S = "__NSConstantStringImpl_";
+
+  std::string tmpName = InFileName;
+  unsigned i;
+  for (i=0; i < tmpName.length(); i++) {
+    char c = tmpName.at(i);
+    // replace any non-alphanumeric characters with '_'.
+    if (!isAlphanumeric(c))
+      tmpName[i] = '_';
+  }
+  S += tmpName;
+  S += "_";
+  S += utostr(NumObjCStringLiterals++);
+
+  Preamble += "static __NSConstantStringImpl " + S;
+  Preamble += " __attribute__ ((section (\"__DATA, __cfstring\"))) = {__CFConstantStringClassReference,";
+  Preamble += "0x000007c8,"; // utf8_str
+  // The pretty printer for StringLiteral handles escape characters properly.
+  std::string prettyBufS;
+  llvm::raw_string_ostream prettyBuf(prettyBufS);
+  Exp->getString()->printPretty(prettyBuf, nullptr, PrintingPolicy(LangOpts));
+  Preamble += prettyBuf.str();
+  Preamble += ",";
+  Preamble += utostr(Exp->getString()->getByteLength()) + "};\n";
+
+  VarDecl *NewVD = VarDecl::Create(*Context, TUDecl, SourceLocation(),
+                                   SourceLocation(), &Context->Idents.get(S),
+                                   strType, nullptr, SC_Static);
+  DeclRefExpr *DRE = new (Context) DeclRefExpr(NewVD, false, strType, VK_LValue,
+                                               SourceLocation());
+  Expr *Unop = new (Context) UnaryOperator(DRE, UO_AddrOf,
+                                 Context->getPointerType(DRE->getType()),
+                                           VK_RValue, OK_Ordinary,
+                                           SourceLocation());
+  // cast to NSConstantString *
+  CastExpr *cast = NoTypeInfoCStyleCastExpr(Context, Exp->getType(),
+                                            CK_CPointerToObjCPointerCast, Unop);
+  ReplaceStmt(Exp, cast);
+  // delete Exp; leak for now, see RewritePropertyOrImplicitSetter() usage for more info.
+  return cast;
+}
+
+// struct objc_super { struct objc_object *receiver; struct objc_class *super; };
+QualType RewriteObjC::getSuperStructType() {
+  if (!SuperStructDecl) {
+    SuperStructDecl = RecordDecl::Create(*Context, TTK_Struct, TUDecl,
+                                         SourceLocation(), SourceLocation(),
+                                         &Context->Idents.get("objc_super"));
+    QualType FieldTypes[2];
+
+    // struct objc_object *receiver;
+    FieldTypes[0] = Context->getObjCIdType();
+    // struct objc_class *super;
+    FieldTypes[1] = Context->getObjCClassType();
+
+    // Create fields
+    for (unsigned i = 0; i < 2; ++i) {
+      SuperStructDecl->addDecl(FieldDecl::Create(*Context, SuperStructDecl,
+                                                 SourceLocation(),
+                                                 SourceLocation(), nullptr,
+                                                 FieldTypes[i], nullptr,
+                                                 /*BitWidth=*/nullptr,
+                                                 /*Mutable=*/false,
+                                                 ICIS_NoInit));
+    }
+
+    SuperStructDecl->completeDefinition();
+  }
+  return Context->getTagDeclType(SuperStructDecl);
+}
+
+QualType RewriteObjC::getConstantStringStructType() {
+  if (!ConstantStringDecl) {
+    ConstantStringDecl = RecordDecl::Create(*Context, TTK_Struct, TUDecl,
+                                            SourceLocation(), SourceLocation(),
+                         &Context->Idents.get("__NSConstantStringImpl"));
+    QualType FieldTypes[4];
+
+    // struct objc_object *receiver;
+    FieldTypes[0] = Context->getObjCIdType();
+    // int flags;
+    FieldTypes[1] = Context->IntTy;
+    // char *str;
+    FieldTypes[2] = Context->getPointerType(Context->CharTy);
+    // long length;
+    FieldTypes[3] = Context->LongTy;
+
+    // Create fields
+    for (unsigned i = 0; i < 4; ++i) {
+      ConstantStringDecl->addDecl(FieldDecl::Create(*Context,
+                                                    ConstantStringDecl,
+                                                    SourceLocation(),
+                                                    SourceLocation(), nullptr,
+                                                    FieldTypes[i], nullptr,
+                                                    /*BitWidth=*/nullptr,
+                                                    /*Mutable=*/true,
+                                                    ICIS_NoInit));
+    }
+
+    ConstantStringDecl->completeDefinition();
+  }
+  return Context->getTagDeclType(ConstantStringDecl);
+}
+
+CallExpr *RewriteObjC::SynthMsgSendStretCallExpr(FunctionDecl *MsgSendStretFlavor,
+                                                QualType msgSendType, 
+                                                QualType returnType, 
+                                                SmallVectorImpl<QualType> &ArgTypes,
+                                                SmallVectorImpl<Expr*> &MsgExprs,
+                                                ObjCMethodDecl *Method) {
+  // Create a reference to the objc_msgSend_stret() declaration.
+  DeclRefExpr *STDRE = new (Context) DeclRefExpr(MsgSendStretFlavor,
+                                                 false, msgSendType,
+                                                 VK_LValue, SourceLocation());
+  // Need to cast objc_msgSend_stret to "void *" (see above comment).
+  CastExpr *cast = NoTypeInfoCStyleCastExpr(Context,
+                                  Context->getPointerType(Context->VoidTy),
+                                  CK_BitCast, STDRE);
+  // Now do the "normal" pointer to function cast.
+  QualType castType = getSimpleFunctionType(returnType, ArgTypes,
+                                            Method ? Method->isVariadic()
+                                                   : false);
+  castType = Context->getPointerType(castType);
+  cast = NoTypeInfoCStyleCastExpr(Context, castType, CK_BitCast,
+                                            cast);
+  
+  // Don't forget the parens to enforce the proper binding.
+  ParenExpr *PE = new (Context) ParenExpr(SourceLocation(), SourceLocation(), cast);
+  
+  const FunctionType *FT = msgSendType->getAs<FunctionType>();
+  CallExpr *STCE = new (Context) CallExpr(
+      *Context, PE, MsgExprs, FT->getReturnType(), VK_RValue, SourceLocation());
+  return STCE;
+  
+}
+
+
+Stmt *RewriteObjC::SynthMessageExpr(ObjCMessageExpr *Exp,
+                                    SourceLocation StartLoc,
+                                    SourceLocation EndLoc) {
+  if (!SelGetUidFunctionDecl)
+    SynthSelGetUidFunctionDecl();
+  if (!MsgSendFunctionDecl)
+    SynthMsgSendFunctionDecl();
+  if (!MsgSendSuperFunctionDecl)
+    SynthMsgSendSuperFunctionDecl();
+  if (!MsgSendStretFunctionDecl)
+    SynthMsgSendStretFunctionDecl();
+  if (!MsgSendSuperStretFunctionDecl)
+    SynthMsgSendSuperStretFunctionDecl();
+  if (!MsgSendFpretFunctionDecl)
+    SynthMsgSendFpretFunctionDecl();
+  if (!GetClassFunctionDecl)
+    SynthGetClassFunctionDecl();
+  if (!GetSuperClassFunctionDecl)
+    SynthGetSuperClassFunctionDecl();
+  if (!GetMetaClassFunctionDecl)
+    SynthGetMetaClassFunctionDecl();
+
+  // default to objc_msgSend().
+  FunctionDecl *MsgSendFlavor = MsgSendFunctionDecl;
+  // May need to use objc_msgSend_stret() as well.
+  FunctionDecl *MsgSendStretFlavor = nullptr;
+  if (ObjCMethodDecl *mDecl = Exp->getMethodDecl()) {
+    QualType resultType = mDecl->getReturnType();
+    if (resultType->isRecordType())
+      MsgSendStretFlavor = MsgSendStretFunctionDecl;
+    else if (resultType->isRealFloatingType())
+      MsgSendFlavor = MsgSendFpretFunctionDecl;
+  }
+
+  // Synthesize a call to objc_msgSend().
+  SmallVector<Expr*, 8> MsgExprs;
+  switch (Exp->getReceiverKind()) {
+  case ObjCMessageExpr::SuperClass: {
+    MsgSendFlavor = MsgSendSuperFunctionDecl;
+    if (MsgSendStretFlavor)
+      MsgSendStretFlavor = MsgSendSuperStretFunctionDecl;
+    assert(MsgSendFlavor && "MsgSendFlavor is NULL!");
+
+    ObjCInterfaceDecl *ClassDecl = CurMethodDef->getClassInterface();
+
+    SmallVector<Expr*, 4> InitExprs;
+
+    // set the receiver to self, the first argument to all methods.
+    InitExprs.push_back(
+      NoTypeInfoCStyleCastExpr(Context, Context->getObjCIdType(),
+                               CK_BitCast,
+                   new (Context) DeclRefExpr(CurMethodDef->getSelfDecl(),
+                                             false,
+                                             Context->getObjCIdType(),
+                                             VK_RValue,
+                                             SourceLocation()))
+                        ); // set the 'receiver'.
+
+    // (id)class_getSuperclass((Class)objc_getClass("CurrentClass"))
+    SmallVector<Expr*, 8> ClsExprs;
+    ClsExprs.push_back(getStringLiteral(ClassDecl->getIdentifier()->getName()));
+    CallExpr *Cls = SynthesizeCallToFunctionDecl(GetMetaClassFunctionDecl,
+                                                 &ClsExprs[0],
+                                                 ClsExprs.size(),
+                                                 StartLoc,
+                                                 EndLoc);
+    // (Class)objc_getClass("CurrentClass")
+    CastExpr *ArgExpr = NoTypeInfoCStyleCastExpr(Context,
+                                             Context->getObjCClassType(),
+                                             CK_BitCast, Cls);
+    ClsExprs.clear();
+    ClsExprs.push_back(ArgExpr);
+    Cls = SynthesizeCallToFunctionDecl(GetSuperClassFunctionDecl,
+                                       &ClsExprs[0], ClsExprs.size(),
+                                       StartLoc, EndLoc);
+    
+    // (id)class_getSuperclass((Class)objc_getClass("CurrentClass"))
+    // To turn off a warning, type-cast to 'id'
+    InitExprs.push_back( // set 'super class', using class_getSuperclass().
+                        NoTypeInfoCStyleCastExpr(Context,
+                                                 Context->getObjCIdType(),
+                                                 CK_BitCast, Cls));
+    // struct objc_super
+    QualType superType = getSuperStructType();
+    Expr *SuperRep;
+
+    if (LangOpts.MicrosoftExt) {
+      SynthSuperConstructorFunctionDecl();
+      // Simulate a constructor call...
+      DeclRefExpr *DRE = new (Context) DeclRefExpr(SuperConstructorFunctionDecl,
+                                                   false, superType, VK_LValue,
+                                                   SourceLocation());
+      SuperRep = new (Context) CallExpr(*Context, DRE, InitExprs,
+                                        superType, VK_LValue,
+                                        SourceLocation());
+      // The code for super is a little tricky to prevent collision with
+      // the structure definition in the header. The rewriter has it's own
+      // internal definition (__rw_objc_super) that is uses. This is why
+      // we need the cast below. For example:
+      // (struct objc_super *)&__rw_objc_super((id)self, (id)objc_getClass("SUPER"))
+      //
+      SuperRep = new (Context) UnaryOperator(SuperRep, UO_AddrOf,
+                               Context->getPointerType(SuperRep->getType()),
+                                             VK_RValue, OK_Ordinary,
+                                             SourceLocation());
+      SuperRep = NoTypeInfoCStyleCastExpr(Context,
+                                          Context->getPointerType(superType),
+                                          CK_BitCast, SuperRep);
+    } else {
+      // (struct objc_super) { <exprs from above> }
+      InitListExpr *ILE =
+        new (Context) InitListExpr(*Context, SourceLocation(), InitExprs,
+                                   SourceLocation());
+      TypeSourceInfo *superTInfo
+        = Context->getTrivialTypeSourceInfo(superType);
+      SuperRep = new (Context) CompoundLiteralExpr(SourceLocation(), superTInfo,
+                                                   superType, VK_LValue,
+                                                   ILE, false);
+      // struct objc_super *
+      SuperRep = new (Context) UnaryOperator(SuperRep, UO_AddrOf,
+                               Context->getPointerType(SuperRep->getType()),
+                                             VK_RValue, OK_Ordinary,
+                                             SourceLocation());
+    }
+    MsgExprs.push_back(SuperRep);
+    break;
+  }
+
+  case ObjCMessageExpr::Class: {
+    SmallVector<Expr*, 8> ClsExprs;
+    ObjCInterfaceDecl *Class
+      = Exp->getClassReceiver()->getAs<ObjCObjectType>()->getInterface();
+    IdentifierInfo *clsName = Class->getIdentifier();
+    ClsExprs.push_back(getStringLiteral(clsName->getName()));
+    CallExpr *Cls = SynthesizeCallToFunctionDecl(GetClassFunctionDecl,
+                                                 &ClsExprs[0],
+                                                 ClsExprs.size(), 
+                                                 StartLoc, EndLoc);
+    MsgExprs.push_back(Cls);
+    break;
+  }
+
+  case ObjCMessageExpr::SuperInstance:{
+    MsgSendFlavor = MsgSendSuperFunctionDecl;
+    if (MsgSendStretFlavor)
+      MsgSendStretFlavor = MsgSendSuperStretFunctionDecl;
+    assert(MsgSendFlavor && "MsgSendFlavor is NULL!");
+    ObjCInterfaceDecl *ClassDecl = CurMethodDef->getClassInterface();
+    SmallVector<Expr*, 4> InitExprs;
+
+    InitExprs.push_back(
+      NoTypeInfoCStyleCastExpr(Context, Context->getObjCIdType(),
+                               CK_BitCast,
+                   new (Context) DeclRefExpr(CurMethodDef->getSelfDecl(),
+                                             false,
+                                             Context->getObjCIdType(),
+                                             VK_RValue, SourceLocation()))
+                        ); // set the 'receiver'.
+    
+    // (id)class_getSuperclass((Class)objc_getClass("CurrentClass"))
+    SmallVector<Expr*, 8> ClsExprs;
+    ClsExprs.push_back(getStringLiteral(ClassDecl->getIdentifier()->getName()));
+    CallExpr *Cls = SynthesizeCallToFunctionDecl(GetClassFunctionDecl,
+                                                 &ClsExprs[0],
+                                                 ClsExprs.size(), 
+                                                 StartLoc, EndLoc);
+    // (Class)objc_getClass("CurrentClass")
+    CastExpr *ArgExpr = NoTypeInfoCStyleCastExpr(Context,
+                                                 Context->getObjCClassType(),
+                                                 CK_BitCast, Cls);
+    ClsExprs.clear();
+    ClsExprs.push_back(ArgExpr);
+    Cls = SynthesizeCallToFunctionDecl(GetSuperClassFunctionDecl,
+                                       &ClsExprs[0], ClsExprs.size(),
+                                       StartLoc, EndLoc);
+    
+    // (id)class_getSuperclass((Class)objc_getClass("CurrentClass"))
+    // To turn off a warning, type-cast to 'id'
+    InitExprs.push_back(
+      // set 'super class', using class_getSuperclass().
+      NoTypeInfoCStyleCastExpr(Context, Context->getObjCIdType(),
+                               CK_BitCast, Cls));
+    // struct objc_super
+    QualType superType = getSuperStructType();
+    Expr *SuperRep;
+
+    if (LangOpts.MicrosoftExt) {
+      SynthSuperConstructorFunctionDecl();
+      // Simulate a constructor call...
+      DeclRefExpr *DRE = new (Context) DeclRefExpr(SuperConstructorFunctionDecl,
+                                                   false, superType, VK_LValue,
+                                                   SourceLocation());
+      SuperRep = new (Context) CallExpr(*Context, DRE, InitExprs,
+                                        superType, VK_LValue, SourceLocation());
+      // The code for super is a little tricky to prevent collision with
+      // the structure definition in the header. The rewriter has it's own
+      // internal definition (__rw_objc_super) that is uses. This is why
+      // we need the cast below. For example:
+      // (struct objc_super *)&__rw_objc_super((id)self, (id)objc_getClass("SUPER"))
+      //
+      SuperRep = new (Context) UnaryOperator(SuperRep, UO_AddrOf,
+                               Context->getPointerType(SuperRep->getType()),
+                               VK_RValue, OK_Ordinary,
+                               SourceLocation());
+      SuperRep = NoTypeInfoCStyleCastExpr(Context,
+                               Context->getPointerType(superType),
+                               CK_BitCast, SuperRep);
+    } else {
+      // (struct objc_super) { <exprs from above> }
+      InitListExpr *ILE =
+        new (Context) InitListExpr(*Context, SourceLocation(), InitExprs,
+                                   SourceLocation());
+      TypeSourceInfo *superTInfo
+        = Context->getTrivialTypeSourceInfo(superType);
+      SuperRep = new (Context) CompoundLiteralExpr(SourceLocation(), superTInfo,
+                                                   superType, VK_RValue, ILE,
+                                                   false);
+    }
+    MsgExprs.push_back(SuperRep);
+    break;
+  }
+
+  case ObjCMessageExpr::Instance: {
+    // Remove all type-casts because it may contain objc-style types; e.g.
+    // Foo<Proto> *.
+    Expr *recExpr = Exp->getInstanceReceiver();
+    while (CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(recExpr))
+      recExpr = CE->getSubExpr();
+    CastKind CK = recExpr->getType()->isObjCObjectPointerType()
+                    ? CK_BitCast : recExpr->getType()->isBlockPointerType()
+                                     ? CK_BlockPointerToObjCPointerCast
+                                     : CK_CPointerToObjCPointerCast;
+
+    recExpr = NoTypeInfoCStyleCastExpr(Context, Context->getObjCIdType(),
+                                       CK, recExpr);
+    MsgExprs.push_back(recExpr);
+    break;
+  }
+  }
+
+  // Create a call to sel_registerName("selName"), it will be the 2nd argument.
+  SmallVector<Expr*, 8> SelExprs;
+  SelExprs.push_back(getStringLiteral(Exp->getSelector().getAsString()));
+  CallExpr *SelExp = SynthesizeCallToFunctionDecl(SelGetUidFunctionDecl,
+                                                 &SelExprs[0], SelExprs.size(),
+                                                  StartLoc,
+                                                  EndLoc);
+  MsgExprs.push_back(SelExp);
+
+  // Now push any user supplied arguments.
+  for (unsigned i = 0; i < Exp->getNumArgs(); i++) {
+    Expr *userExpr = Exp->getArg(i);
+    // Make all implicit casts explicit...ICE comes in handy:-)
+    if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(userExpr)) {
+      // Reuse the ICE type, it is exactly what the doctor ordered.
+      QualType type = ICE->getType();
+      if (needToScanForQualifiers(type))
+        type = Context->getObjCIdType();
+      // Make sure we convert "type (^)(...)" to "type (*)(...)".
+      (void)convertBlockPointerToFunctionPointer(type);
+      const Expr *SubExpr = ICE->IgnoreParenImpCasts();
+      CastKind CK;
+      if (SubExpr->getType()->isIntegralType(*Context) && 
+          type->isBooleanType()) {
+        CK = CK_IntegralToBoolean;
+      } else if (type->isObjCObjectPointerType()) {
+        if (SubExpr->getType()->isBlockPointerType()) {
+          CK = CK_BlockPointerToObjCPointerCast;
+        } else if (SubExpr->getType()->isPointerType()) {
+          CK = CK_CPointerToObjCPointerCast;
+        } else {
+          CK = CK_BitCast;
+        }
+      } else {
+        CK = CK_BitCast;
+      }
+
+      userExpr = NoTypeInfoCStyleCastExpr(Context, type, CK, userExpr);
+    }
+    // Make id<P...> cast into an 'id' cast.
+    else if (CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(userExpr)) {
+      if (CE->getType()->isObjCQualifiedIdType()) {
+        while ((CE = dyn_cast<CStyleCastExpr>(userExpr)))
+          userExpr = CE->getSubExpr();
+        CastKind CK;
+        if (userExpr->getType()->isIntegralType(*Context)) {
+          CK = CK_IntegralToPointer;
+        } else if (userExpr->getType()->isBlockPointerType()) {
+          CK = CK_BlockPointerToObjCPointerCast;
+        } else if (userExpr->getType()->isPointerType()) {
+          CK = CK_CPointerToObjCPointerCast;
+        } else {
+          CK = CK_BitCast;
+        }
+        userExpr = NoTypeInfoCStyleCastExpr(Context, Context->getObjCIdType(),
+                                            CK, userExpr);
+      }
+    }
+    MsgExprs.push_back(userExpr);
+    // We've transferred the ownership to MsgExprs. For now, we *don't* null
+    // out the argument in the original expression (since we aren't deleting
+    // the ObjCMessageExpr). See RewritePropertyOrImplicitSetter() usage for more info.
+    //Exp->setArg(i, 0);
+  }
+  // Generate the funky cast.
+  CastExpr *cast;
+  SmallVector<QualType, 8> ArgTypes;
+  QualType returnType;
+
+  // Push 'id' and 'SEL', the 2 implicit arguments.
+  if (MsgSendFlavor == MsgSendSuperFunctionDecl)
+    ArgTypes.push_back(Context->getPointerType(getSuperStructType()));
+  else
+    ArgTypes.push_back(Context->getObjCIdType());
+  ArgTypes.push_back(Context->getObjCSelType());
+  if (ObjCMethodDecl *OMD = Exp->getMethodDecl()) {
+    // Push any user argument types.
+    for (const auto *PI : OMD->params()) {
+      QualType t = PI->getType()->isObjCQualifiedIdType()
+                     ? Context->getObjCIdType()
+                     : PI->getType();
+      // Make sure we convert "t (^)(...)" to "t (*)(...)".
+      (void)convertBlockPointerToFunctionPointer(t);
+      ArgTypes.push_back(t);
+    }
+    returnType = Exp->getType();
+    convertToUnqualifiedObjCType(returnType);
+    (void)convertBlockPointerToFunctionPointer(returnType);
+  } else {
+    returnType = Context->getObjCIdType();
+  }
+  // Get the type, we will need to reference it in a couple spots.
+  QualType msgSendType = MsgSendFlavor->getType();
+
+  // Create a reference to the objc_msgSend() declaration.
+  DeclRefExpr *DRE = new (Context) DeclRefExpr(MsgSendFlavor, false, msgSendType,
+                                               VK_LValue, SourceLocation());
+
+  // Need to cast objc_msgSend to "void *" (to workaround a GCC bandaid).
+  // If we don't do this cast, we get the following bizarre warning/note:
+  // xx.m:13: warning: function called through a non-compatible type
+  // xx.m:13: note: if this code is reached, the program will abort
+  cast = NoTypeInfoCStyleCastExpr(Context,
+                                  Context->getPointerType(Context->VoidTy),
+                                  CK_BitCast, DRE);
+
+  // Now do the "normal" pointer to function cast.
+  // If we don't have a method decl, force a variadic cast.
+  const ObjCMethodDecl *MD = Exp->getMethodDecl();
+  QualType castType =
+    getSimpleFunctionType(returnType, ArgTypes, MD ? MD->isVariadic() : true);
+  castType = Context->getPointerType(castType);
+  cast = NoTypeInfoCStyleCastExpr(Context, castType, CK_BitCast,
+                                  cast);
+
+  // Don't forget the parens to enforce the proper binding.
+  ParenExpr *PE = new (Context) ParenExpr(StartLoc, EndLoc, cast);
+
+  const FunctionType *FT = msgSendType->getAs<FunctionType>();
+  CallExpr *CE = new (Context)
+      CallExpr(*Context, PE, MsgExprs, FT->getReturnType(), VK_RValue, EndLoc);
+  Stmt *ReplacingStmt = CE;
+  if (MsgSendStretFlavor) {
+    // We have the method which returns a struct/union. Must also generate
+    // call to objc_msgSend_stret and hang both varieties on a conditional
+    // expression which dictate which one to envoke depending on size of
+    // method's return type.
+    
+    CallExpr *STCE = SynthMsgSendStretCallExpr(MsgSendStretFlavor, 
+                                               msgSendType, returnType, 
+                                               ArgTypes, MsgExprs,
+                                               Exp->getMethodDecl());
+
+    // Build sizeof(returnType)
+    UnaryExprOrTypeTraitExpr *sizeofExpr =
+       new (Context) UnaryExprOrTypeTraitExpr(UETT_SizeOf,
+                                 Context->getTrivialTypeSourceInfo(returnType),
+                                 Context->getSizeType(), SourceLocation(),
+                                 SourceLocation());
+    // (sizeof(returnType) <= 8 ? objc_msgSend(...) : objc_msgSend_stret(...))
+    // FIXME: Value of 8 is base on ppc32/x86 ABI for the most common cases.
+    // For X86 it is more complicated and some kind of target specific routine
+    // is needed to decide what to do.
+    unsigned IntSize =
+      static_cast<unsigned>(Context->getTypeSize(Context->IntTy));
+    IntegerLiteral *limit = IntegerLiteral::Create(*Context,
+                                                   llvm::APInt(IntSize, 8),
+                                                   Context->IntTy,
+                                                   SourceLocation());
+    BinaryOperator *lessThanExpr = 
+      new (Context) BinaryOperator(sizeofExpr, limit, BO_LE, Context->IntTy,
+                                   VK_RValue, OK_Ordinary, SourceLocation(),
+                                   false);
+    // (sizeof(returnType) <= 8 ? objc_msgSend(...) : objc_msgSend_stret(...))
+    ConditionalOperator *CondExpr =
+      new (Context) ConditionalOperator(lessThanExpr,
+                                        SourceLocation(), CE,
+                                        SourceLocation(), STCE,
+                                        returnType, VK_RValue, OK_Ordinary);
+    ReplacingStmt = new (Context) ParenExpr(SourceLocation(), SourceLocation(), 
+                                            CondExpr);
+  }
+  // delete Exp; leak for now, see RewritePropertyOrImplicitSetter() usage for more info.
+  return ReplacingStmt;
+}
+
+Stmt *RewriteObjC::RewriteMessageExpr(ObjCMessageExpr *Exp) {
+  Stmt *ReplacingStmt = SynthMessageExpr(Exp, Exp->getLocStart(),
+                                         Exp->getLocEnd());
+
+  // Now do the actual rewrite.
+  ReplaceStmt(Exp, ReplacingStmt);
+
+  // delete Exp; leak for now, see RewritePropertyOrImplicitSetter() usage for more info.
+  return ReplacingStmt;
+}
+
+// typedef struct objc_object Protocol;
+QualType RewriteObjC::getProtocolType() {
+  if (!ProtocolTypeDecl) {
+    TypeSourceInfo *TInfo
+      = Context->getTrivialTypeSourceInfo(Context->getObjCIdType());
+    ProtocolTypeDecl = TypedefDecl::Create(*Context, TUDecl,
+                                           SourceLocation(), SourceLocation(),
+                                           &Context->Idents.get("Protocol"),
+                                           TInfo);
+  }
+  return Context->getTypeDeclType(ProtocolTypeDecl);
+}
+
+/// RewriteObjCProtocolExpr - Rewrite a protocol expression into
+/// a synthesized/forward data reference (to the protocol's metadata).
+/// The forward references (and metadata) are generated in
+/// RewriteObjC::HandleTranslationUnit().
+Stmt *RewriteObjC::RewriteObjCProtocolExpr(ObjCProtocolExpr *Exp) {
+  std::string Name = "_OBJC_PROTOCOL_" + Exp->getProtocol()->getNameAsString();
+  IdentifierInfo *ID = &Context->Idents.get(Name);
+  VarDecl *VD = VarDecl::Create(*Context, TUDecl, SourceLocation(),
+                                SourceLocation(), ID, getProtocolType(),
+                                nullptr, SC_Extern);
+  DeclRefExpr *DRE = new (Context) DeclRefExpr(VD, false, getProtocolType(),
+                                               VK_LValue, SourceLocation());
+  Expr *DerefExpr = new (Context) UnaryOperator(DRE, UO_AddrOf,
+                             Context->getPointerType(DRE->getType()),
+                             VK_RValue, OK_Ordinary, SourceLocation());
+  CastExpr *castExpr = NoTypeInfoCStyleCastExpr(Context, DerefExpr->getType(),
+                                                CK_BitCast,
+                                                DerefExpr);
+  ReplaceStmt(Exp, castExpr);
+  ProtocolExprDecls.insert(Exp->getProtocol()->getCanonicalDecl());
+  // delete Exp; leak for now, see RewritePropertyOrImplicitSetter() usage for more info.
+  return castExpr;
+
+}
+
+bool RewriteObjC::BufferContainsPPDirectives(const char *startBuf,
+                                             const char *endBuf) {
+  while (startBuf < endBuf) {
+    if (*startBuf == '#') {
+      // Skip whitespace.
+      for (++startBuf; startBuf[0] == ' ' || startBuf[0] == '\t'; ++startBuf)
+        ;
+      if (!strncmp(startBuf, "if", strlen("if")) ||
+          !strncmp(startBuf, "ifdef", strlen("ifdef")) ||
+          !strncmp(startBuf, "ifndef", strlen("ifndef")) ||
+          !strncmp(startBuf, "define", strlen("define")) ||
+          !strncmp(startBuf, "undef", strlen("undef")) ||
+          !strncmp(startBuf, "else", strlen("else")) ||
+          !strncmp(startBuf, "elif", strlen("elif")) ||
+          !strncmp(startBuf, "endif", strlen("endif")) ||
+          !strncmp(startBuf, "pragma", strlen("pragma")) ||
+          !strncmp(startBuf, "include", strlen("include")) ||
+          !strncmp(startBuf, "import", strlen("import")) ||
+          !strncmp(startBuf, "include_next", strlen("include_next")))
+        return true;
+    }
+    startBuf++;
+  }
+  return false;
+}
+
+/// RewriteObjCInternalStruct - Rewrite one internal struct corresponding to
+/// an objective-c class with ivars.
+void RewriteObjC::RewriteObjCInternalStruct(ObjCInterfaceDecl *CDecl,
+                                               std::string &Result) {
+  assert(CDecl && "Class missing in SynthesizeObjCInternalStruct");
+  assert(CDecl->getName() != "" &&
+         "Name missing in SynthesizeObjCInternalStruct");
+  // Do not synthesize more than once.
+  if (ObjCSynthesizedStructs.count(CDecl))
+    return;
+  ObjCInterfaceDecl *RCDecl = CDecl->getSuperClass();
+  int NumIvars = CDecl->ivar_size();
+  SourceLocation LocStart = CDecl->getLocStart();
+  SourceLocation LocEnd = CDecl->getEndOfDefinitionLoc();
+
+  const char *startBuf = SM->getCharacterData(LocStart);
+  const char *endBuf = SM->getCharacterData(LocEnd);
+
+  // If no ivars and no root or if its root, directly or indirectly,
+  // have no ivars (thus not synthesized) then no need to synthesize this class.
+  if ((!CDecl->isThisDeclarationADefinition() || NumIvars == 0) &&
+      (!RCDecl || !ObjCSynthesizedStructs.count(RCDecl))) {
+    endBuf += Lexer::MeasureTokenLength(LocEnd, *SM, LangOpts);
+    ReplaceText(LocStart, endBuf-startBuf, Result);
+    return;
+  }
+
+  // FIXME: This has potential of causing problem. If
+  // SynthesizeObjCInternalStruct is ever called recursively.
+  Result += "\nstruct ";
+  Result += CDecl->getNameAsString();
+  if (LangOpts.MicrosoftExt)
+    Result += "_IMPL";
+
+  if (NumIvars > 0) {
+    const char *cursor = strchr(startBuf, '{');
+    assert((cursor && endBuf)
+           && "SynthesizeObjCInternalStruct - malformed @interface");
+    // If the buffer contains preprocessor directives, we do more fine-grained
+    // rewrites. This is intended to fix code that looks like (which occurs in
+    // NSURL.h, for example):
+    //
+    // #ifdef XYZ
+    // @interface Foo : NSObject
+    // #else
+    // @interface FooBar : NSObject
+    // #endif
+    // {
+    //    int i;
+    // }
+    // @end
+    //
+    // This clause is segregated to avoid breaking the common case.
+    if (BufferContainsPPDirectives(startBuf, cursor)) {
+      SourceLocation L = RCDecl ? CDecl->getSuperClassLoc() :
+                                  CDecl->getAtStartLoc();
+      const char *endHeader = SM->getCharacterData(L);
+      endHeader += Lexer::MeasureTokenLength(L, *SM, LangOpts);
+
+      if (CDecl->protocol_begin() != CDecl->protocol_end()) {
+        // advance to the end of the referenced protocols.
+        while (endHeader < cursor && *endHeader != '>') endHeader++;
+        endHeader++;
+      }
+      // rewrite the original header
+      ReplaceText(LocStart, endHeader-startBuf, Result);
+    } else {
+      // rewrite the original header *without* disturbing the '{'
+      ReplaceText(LocStart, cursor-startBuf, Result);
+    }
+    if (RCDecl && ObjCSynthesizedStructs.count(RCDecl)) {
+      Result = "\n    struct ";
+      Result += RCDecl->getNameAsString();
+      Result += "_IMPL ";
+      Result += RCDecl->getNameAsString();
+      Result += "_IVARS;\n";
+
+      // insert the super class structure definition.
+      SourceLocation OnePastCurly =
+        LocStart.getLocWithOffset(cursor-startBuf+1);
+      InsertText(OnePastCurly, Result);
+    }
+    cursor++; // past '{'
+
+    // Now comment out any visibility specifiers.
+    while (cursor < endBuf) {
+      if (*cursor == '@') {
+        SourceLocation atLoc = LocStart.getLocWithOffset(cursor-startBuf);
+        // Skip whitespace.
+        for (++cursor; cursor[0] == ' ' || cursor[0] == '\t'; ++cursor)
+          /*scan*/;
+
+        // FIXME: presence of @public, etc. inside comment results in
+        // this transformation as well, which is still correct c-code.
+        if (!strncmp(cursor, "public", strlen("public")) ||
+            !strncmp(cursor, "private", strlen("private")) ||
+            !strncmp(cursor, "package", strlen("package")) ||
+            !strncmp(cursor, "protected", strlen("protected")))
+          InsertText(atLoc, "// ");
+      }
+      // FIXME: If there are cases where '<' is used in ivar declaration part
+      // of user code, then scan the ivar list and use needToScanForQualifiers
+      // for type checking.
+      else if (*cursor == '<') {
+        SourceLocation atLoc = LocStart.getLocWithOffset(cursor-startBuf);
+        InsertText(atLoc, "/* ");
+        cursor = strchr(cursor, '>');
+        cursor++;
+        atLoc = LocStart.getLocWithOffset(cursor-startBuf);
+        InsertText(atLoc, " */");
+      } else if (*cursor == '^') { // rewrite block specifier.
+        SourceLocation caretLoc = LocStart.getLocWithOffset(cursor-startBuf);
+        ReplaceText(caretLoc, 1, "*");
+      }
+      cursor++;
+    }
+    // Don't forget to add a ';'!!
+    InsertText(LocEnd.getLocWithOffset(1), ";");
+  } else { // we don't have any instance variables - insert super struct.
+    endBuf += Lexer::MeasureTokenLength(LocEnd, *SM, LangOpts);
+    Result += " {\n    struct ";
+    Result += RCDecl->getNameAsString();
+    Result += "_IMPL ";
+    Result += RCDecl->getNameAsString();
+    Result += "_IVARS;\n};\n";
+    ReplaceText(LocStart, endBuf-startBuf, Result);
+  }
+  // Mark this struct as having been generated.
+  if (!ObjCSynthesizedStructs.insert(CDecl))
+    llvm_unreachable("struct already synthesize- SynthesizeObjCInternalStruct");
+}
+
+//===----------------------------------------------------------------------===//
+// Meta Data Emission
+//===----------------------------------------------------------------------===//
+
+
+/// RewriteImplementations - This routine rewrites all method implementations
+/// and emits meta-data.
+
+void RewriteObjC::RewriteImplementations() {
+  int ClsDefCount = ClassImplementation.size();
+  int CatDefCount = CategoryImplementation.size();
+
+  // Rewrite implemented methods
+  for (int i = 0; i < ClsDefCount; i++)
+    RewriteImplementationDecl(ClassImplementation[i]);
+
+  for (int i = 0; i < CatDefCount; i++)
+    RewriteImplementationDecl(CategoryImplementation[i]);
+}
+
+void RewriteObjC::RewriteByRefString(std::string &ResultStr, 
+                                     const std::string &Name,
+                                     ValueDecl *VD, bool def) {
+  assert(BlockByRefDeclNo.count(VD) && 
+         "RewriteByRefString: ByRef decl missing");
+  if (def)
+    ResultStr += "struct ";
+  ResultStr += "__Block_byref_" + Name + 
+    "_" + utostr(BlockByRefDeclNo[VD]) ;
+}
+
+static bool HasLocalVariableExternalStorage(ValueDecl *VD) {
+  if (VarDecl *Var = dyn_cast<VarDecl>(VD))
+    return (Var->isFunctionOrMethodVarDecl() && !Var->hasLocalStorage());
+  return false;
+}
+
+std::string RewriteObjC::SynthesizeBlockFunc(BlockExpr *CE, int i,
+                                                   StringRef funcName,
+                                                   std::string Tag) {
+  const FunctionType *AFT = CE->getFunctionType();
+  QualType RT = AFT->getReturnType();
+  std::string StructRef = "struct " + Tag;
+  std::string S = "static " + RT.getAsString(Context->getPrintingPolicy()) + " __" +
+                  funcName.str() + "_" + "block_func_" + utostr(i);
+
+  BlockDecl *BD = CE->getBlockDecl();
+
+  if (isa<FunctionNoProtoType>(AFT)) {
+    // No user-supplied arguments. Still need to pass in a pointer to the
+    // block (to reference imported block decl refs).
+    S += "(" + StructRef + " *__cself)";
+  } else if (BD->param_empty()) {
+    S += "(" + StructRef + " *__cself)";
+  } else {
+    const FunctionProtoType *FT = cast<FunctionProtoType>(AFT);
+    assert(FT && "SynthesizeBlockFunc: No function proto");
+    S += '(';
+    // first add the implicit argument.
+    S += StructRef + " *__cself, ";
+    std::string ParamStr;
+    for (BlockDecl::param_iterator AI = BD->param_begin(),
+         E = BD->param_end(); AI != E; ++AI) {
+      if (AI != BD->param_begin()) S += ", ";
+      ParamStr = (*AI)->getNameAsString();
+      QualType QT = (*AI)->getType();
+      (void)convertBlockPointerToFunctionPointer(QT);
+      QT.getAsStringInternal(ParamStr, Context->getPrintingPolicy());
+      S += ParamStr;
+    }
+    if (FT->isVariadic()) {
+      if (!BD->param_empty()) S += ", ";
+      S += "...";
+    }
+    S += ')';
+  }
+  S += " {\n";
+
+  // Create local declarations to avoid rewriting all closure decl ref exprs.
+  // First, emit a declaration for all "by ref" decls.
+  for (SmallVectorImpl<ValueDecl *>::iterator I = BlockByRefDecls.begin(),
+       E = BlockByRefDecls.end(); I != E; ++I) {
+    S += "  ";
+    std::string Name = (*I)->getNameAsString();
+    std::string TypeString;
+    RewriteByRefString(TypeString, Name, (*I));
+    TypeString += " *";
+    Name = TypeString + Name;
+    S += Name + " = __cself->" + (*I)->getNameAsString() + "; // bound by ref\n";
+  }
+  // Next, emit a declaration for all "by copy" declarations.
+  for (SmallVectorImpl<ValueDecl *>::iterator I = BlockByCopyDecls.begin(),
+       E = BlockByCopyDecls.end(); I != E; ++I) {
+    S += "  ";
+    // Handle nested closure invocation. For example:
+    //
+    //   void (^myImportedClosure)(void);
+    //   myImportedClosure  = ^(void) { setGlobalInt(x + y); };
+    //
+    //   void (^anotherClosure)(void);
+    //   anotherClosure = ^(void) {
+    //     myImportedClosure(); // import and invoke the closure
+    //   };
+    //
+    if (isTopLevelBlockPointerType((*I)->getType())) {
+      RewriteBlockPointerTypeVariable(S, (*I));
+      S += " = (";
+      RewriteBlockPointerType(S, (*I)->getType());
+      S += ")";
+      S += "__cself->" + (*I)->getNameAsString() + "; // bound by copy\n";
+    }
+    else {
+      std::string Name = (*I)->getNameAsString();
+      QualType QT = (*I)->getType();
+      if (HasLocalVariableExternalStorage(*I))
+        QT = Context->getPointerType(QT);
+      QT.getAsStringInternal(Name, Context->getPrintingPolicy());
+      S += Name + " = __cself->" + 
+                              (*I)->getNameAsString() + "; // bound by copy\n";
+    }
+  }
+  std::string RewrittenStr = RewrittenBlockExprs[CE];
+  const char *cstr = RewrittenStr.c_str();
+  while (*cstr++ != '{') ;
+  S += cstr;
+  S += "\n";
+  return S;
+}
+
+std::string RewriteObjC::SynthesizeBlockHelperFuncs(BlockExpr *CE, int i,
+                                                   StringRef funcName,
+                                                   std::string Tag) {
+  std::string StructRef = "struct " + Tag;
+  std::string S = "static void __";
+
+  S += funcName;
+  S += "_block_copy_" + utostr(i);
+  S += "(" + StructRef;
+  S += "*dst, " + StructRef;
+  S += "*src) {";
+  for (llvm::SmallPtrSet<ValueDecl*,8>::iterator I = ImportedBlockDecls.begin(),
+      E = ImportedBlockDecls.end(); I != E; ++I) {
+    ValueDecl *VD = (*I);
+    S += "_Block_object_assign((void*)&dst->";
+    S += (*I)->getNameAsString();
+    S += ", (void*)src->";
+    S += (*I)->getNameAsString();
+    if (BlockByRefDeclsPtrSet.count((*I)))
+      S += ", " + utostr(BLOCK_FIELD_IS_BYREF) + "/*BLOCK_FIELD_IS_BYREF*/);";
+    else if (VD->getType()->isBlockPointerType())
+      S += ", " + utostr(BLOCK_FIELD_IS_BLOCK) + "/*BLOCK_FIELD_IS_BLOCK*/);";
+    else
+      S += ", " + utostr(BLOCK_FIELD_IS_OBJECT) + "/*BLOCK_FIELD_IS_OBJECT*/);";
+  }
+  S += "}\n";
+  
+  S += "\nstatic void __";
+  S += funcName;
+  S += "_block_dispose_" + utostr(i);
+  S += "(" + StructRef;
+  S += "*src) {";
+  for (llvm::SmallPtrSet<ValueDecl*,8>::iterator I = ImportedBlockDecls.begin(),
+      E = ImportedBlockDecls.end(); I != E; ++I) {
+    ValueDecl *VD = (*I);
+    S += "_Block_object_dispose((void*)src->";
+    S += (*I)->getNameAsString();
+    if (BlockByRefDeclsPtrSet.count((*I)))
+      S += ", " + utostr(BLOCK_FIELD_IS_BYREF) + "/*BLOCK_FIELD_IS_BYREF*/);";
+    else if (VD->getType()->isBlockPointerType())
+      S += ", " + utostr(BLOCK_FIELD_IS_BLOCK) + "/*BLOCK_FIELD_IS_BLOCK*/);";
+    else
+      S += ", " + utostr(BLOCK_FIELD_IS_OBJECT) + "/*BLOCK_FIELD_IS_OBJECT*/);";
+  }
+  S += "}\n";
+  return S;
+}
+
+std::string RewriteObjC::SynthesizeBlockImpl(BlockExpr *CE, std::string Tag, 
+                                             std::string Desc) {
+  std::string S = "\nstruct " + Tag;
+  std::string Constructor = "  " + Tag;
+
+  S += " {\n  struct __block_impl impl;\n";
+  S += "  struct " + Desc;
+  S += "* Desc;\n";
+
+  Constructor += "(void *fp, "; // Invoke function pointer.
+  Constructor += "struct " + Desc; // Descriptor pointer.
+  Constructor += " *desc";
+
+  if (BlockDeclRefs.size()) {
+    // Output all "by copy" declarations.
+    for (SmallVectorImpl<ValueDecl *>::iterator I = BlockByCopyDecls.begin(),
+         E = BlockByCopyDecls.end(); I != E; ++I) {
+      S += "  ";
+      std::string FieldName = (*I)->getNameAsString();
+      std::string ArgName = "_" + FieldName;
+      // Handle nested closure invocation. For example:
+      //
+      //   void (^myImportedBlock)(void);
+      //   myImportedBlock  = ^(void) { setGlobalInt(x + y); };
+      //
+      //   void (^anotherBlock)(void);
+      //   anotherBlock = ^(void) {
+      //     myImportedBlock(); // import and invoke the closure
+      //   };
+      //
+      if (isTopLevelBlockPointerType((*I)->getType())) {
+        S += "struct __block_impl *";
+        Constructor += ", void *" + ArgName;
+      } else {
+        QualType QT = (*I)->getType();
+        if (HasLocalVariableExternalStorage(*I))
+          QT = Context->getPointerType(QT);
+        QT.getAsStringInternal(FieldName, Context->getPrintingPolicy());
+        QT.getAsStringInternal(ArgName, Context->getPrintingPolicy());
+        Constructor += ", " + ArgName;
+      }
+      S += FieldName + ";\n";
+    }
+    // Output all "by ref" declarations.
+    for (SmallVectorImpl<ValueDecl *>::iterator I = BlockByRefDecls.begin(),
+         E = BlockByRefDecls.end(); I != E; ++I) {
+      S += "  ";
+      std::string FieldName = (*I)->getNameAsString();
+      std::string ArgName = "_" + FieldName;
+      {
+        std::string TypeString;
+        RewriteByRefString(TypeString, FieldName, (*I));
+        TypeString += " *";
+        FieldName = TypeString + FieldName;
+        ArgName = TypeString + ArgName;
+        Constructor += ", " + ArgName;
+      }
+      S += FieldName + "; // by ref\n";
+    }
+    // Finish writing the constructor.
+    Constructor += ", int flags=0)";
+    // Initialize all "by copy" arguments.
+    bool firsTime = true;
+    for (SmallVectorImpl<ValueDecl *>::iterator I = BlockByCopyDecls.begin(),
+         E = BlockByCopyDecls.end(); I != E; ++I) {
+      std::string Name = (*I)->getNameAsString();
+        if (firsTime) {
+          Constructor += " : ";
+          firsTime = false;
+        }
+        else
+          Constructor += ", ";
+        if (isTopLevelBlockPointerType((*I)->getType()))
+          Constructor += Name + "((struct __block_impl *)_" + Name + ")";
+        else
+          Constructor += Name + "(_" + Name + ")";
+    }
+    // Initialize all "by ref" arguments.
+    for (SmallVectorImpl<ValueDecl *>::iterator I = BlockByRefDecls.begin(),
+         E = BlockByRefDecls.end(); I != E; ++I) {
+      std::string Name = (*I)->getNameAsString();
+      if (firsTime) {
+        Constructor += " : ";
+        firsTime = false;
+      }
+      else
+        Constructor += ", ";
+      Constructor += Name + "(_" + Name + "->__forwarding)";
+    }
+    
+    Constructor += " {\n";
+    if (GlobalVarDecl)
+      Constructor += "    impl.isa = &_NSConcreteGlobalBlock;\n";
+    else
+      Constructor += "    impl.isa = &_NSConcreteStackBlock;\n";
+    Constructor += "    impl.Flags = flags;\n    impl.FuncPtr = fp;\n";
+
+    Constructor += "    Desc = desc;\n";
+  } else {
+    // Finish writing the constructor.
+    Constructor += ", int flags=0) {\n";
+    if (GlobalVarDecl)
+      Constructor += "    impl.isa = &_NSConcreteGlobalBlock;\n";
+    else
+      Constructor += "    impl.isa = &_NSConcreteStackBlock;\n";
+    Constructor += "    impl.Flags = flags;\n    impl.FuncPtr = fp;\n";
+    Constructor += "    Desc = desc;\n";
+  }
+  Constructor += "  ";
+  Constructor += "}\n";
+  S += Constructor;
+  S += "};\n";
+  return S;
+}
+
+std::string RewriteObjC::SynthesizeBlockDescriptor(std::string DescTag, 
+                                                   std::string ImplTag, int i,
+                                                   StringRef FunName,
+                                                   unsigned hasCopy) {
+  std::string S = "\nstatic struct " + DescTag;
+  
+  S += " {\n  unsigned long reserved;\n";
+  S += "  unsigned long Block_size;\n";
+  if (hasCopy) {
+    S += "  void (*copy)(struct ";
+    S += ImplTag; S += "*, struct ";
+    S += ImplTag; S += "*);\n";
+    
+    S += "  void (*dispose)(struct ";
+    S += ImplTag; S += "*);\n";
+  }
+  S += "} ";
+
+  S += DescTag + "_DATA = { 0, sizeof(struct ";
+  S += ImplTag + ")";
+  if (hasCopy) {
+    S += ", __" + FunName.str() + "_block_copy_" + utostr(i);
+    S += ", __" + FunName.str() + "_block_dispose_" + utostr(i);
+  }
+  S += "};\n";
+  return S;
+}
+
+void RewriteObjC::SynthesizeBlockLiterals(SourceLocation FunLocStart,
+                                          StringRef FunName) {
+  // Insert declaration for the function in which block literal is used.
+  if (CurFunctionDeclToDeclareForBlock && !Blocks.empty())
+    RewriteBlockLiteralFunctionDecl(CurFunctionDeclToDeclareForBlock);
+  bool RewriteSC = (GlobalVarDecl &&
+                    !Blocks.empty() &&
+                    GlobalVarDecl->getStorageClass() == SC_Static &&
+                    GlobalVarDecl->getType().getCVRQualifiers());
+  if (RewriteSC) {
+    std::string SC(" void __");
+    SC += GlobalVarDecl->getNameAsString();
+    SC += "() {}";
+    InsertText(FunLocStart, SC);
+  }
+  
+  // Insert closures that were part of the function.
+  for (unsigned i = 0, count=0; i < Blocks.size(); i++) {
+    CollectBlockDeclRefInfo(Blocks[i]);
+    // Need to copy-in the inner copied-in variables not actually used in this
+    // block.
+    for (int j = 0; j < InnerDeclRefsCount[i]; j++) {
+      DeclRefExpr *Exp = InnerDeclRefs[count++];
+      ValueDecl *VD = Exp->getDecl();
+      BlockDeclRefs.push_back(Exp);
+      if (!VD->hasAttr<BlocksAttr>() && !BlockByCopyDeclsPtrSet.count(VD)) {
+        BlockByCopyDeclsPtrSet.insert(VD);
+        BlockByCopyDecls.push_back(VD);
+      }
+      if (VD->hasAttr<BlocksAttr>() && !BlockByRefDeclsPtrSet.count(VD)) {
+        BlockByRefDeclsPtrSet.insert(VD);
+        BlockByRefDecls.push_back(VD);
+      }
+      // imported objects in the inner blocks not used in the outer
+      // blocks must be copied/disposed in the outer block as well.
+      if (VD->hasAttr<BlocksAttr>() ||
+          VD->getType()->isObjCObjectPointerType() || 
+          VD->getType()->isBlockPointerType())
+        ImportedBlockDecls.insert(VD);
+    }
+
+    std::string ImplTag = "__" + FunName.str() + "_block_impl_" + utostr(i);
+    std::string DescTag = "__" + FunName.str() + "_block_desc_" + utostr(i);
+
+    std::string CI = SynthesizeBlockImpl(Blocks[i], ImplTag, DescTag);
+
+    InsertText(FunLocStart, CI);
+
+    std::string CF = SynthesizeBlockFunc(Blocks[i], i, FunName, ImplTag);
+
+    InsertText(FunLocStart, CF);
+
+    if (ImportedBlockDecls.size()) {
+      std::string HF = SynthesizeBlockHelperFuncs(Blocks[i], i, FunName, ImplTag);
+      InsertText(FunLocStart, HF);
+    }
+    std::string BD = SynthesizeBlockDescriptor(DescTag, ImplTag, i, FunName,
+                                               ImportedBlockDecls.size() > 0);
+    InsertText(FunLocStart, BD);
+
+    BlockDeclRefs.clear();
+    BlockByRefDecls.clear();
+    BlockByRefDeclsPtrSet.clear();
+    BlockByCopyDecls.clear();
+    BlockByCopyDeclsPtrSet.clear();
+    ImportedBlockDecls.clear();
+  }
+  if (RewriteSC) {
+    // Must insert any 'const/volatile/static here. Since it has been
+    // removed as result of rewriting of block literals.
+    std::string SC;
+    if (GlobalVarDecl->getStorageClass() == SC_Static)
+      SC = "static ";
+    if (GlobalVarDecl->getType().isConstQualified())
+      SC += "const ";
+    if (GlobalVarDecl->getType().isVolatileQualified())
+      SC += "volatile ";
+    if (GlobalVarDecl->getType().isRestrictQualified())
+      SC += "restrict ";
+    InsertText(FunLocStart, SC);
+  }
+  
+  Blocks.clear();
+  InnerDeclRefsCount.clear();
+  InnerDeclRefs.clear();
+  RewrittenBlockExprs.clear();
+}
+
+void RewriteObjC::InsertBlockLiteralsWithinFunction(FunctionDecl *FD) {
+  SourceLocation FunLocStart = FD->getTypeSpecStartLoc();
+  StringRef FuncName = FD->getName();
+
+  SynthesizeBlockLiterals(FunLocStart, FuncName);
+}
+
+static void BuildUniqueMethodName(std::string &Name,
+                                  ObjCMethodDecl *MD) {
+  ObjCInterfaceDecl *IFace = MD->getClassInterface();
+  Name = IFace->getName();
+  Name += "__" + MD->getSelector().getAsString();
+  // Convert colons to underscores.
+  std::string::size_type loc = 0;
+  while ((loc = Name.find(":", loc)) != std::string::npos)
+    Name.replace(loc, 1, "_");
+}
+
+void RewriteObjC::InsertBlockLiteralsWithinMethod(ObjCMethodDecl *MD) {
+  //fprintf(stderr,"In InsertBlockLiteralsWitinMethod\n");
+  //SourceLocation FunLocStart = MD->getLocStart();
+  SourceLocation FunLocStart = MD->getLocStart();
+  std::string FuncName;
+  BuildUniqueMethodName(FuncName, MD);
+  SynthesizeBlockLiterals(FunLocStart, FuncName);
+}
+
+void RewriteObjC::GetBlockDeclRefExprs(Stmt *S) {
+  for (Stmt::child_range CI = S->children(); CI; ++CI)
+    if (*CI) {
+      if (BlockExpr *CBE = dyn_cast<BlockExpr>(*CI))
+        GetBlockDeclRefExprs(CBE->getBody());
+      else
+        GetBlockDeclRefExprs(*CI);
+    }
+  // Handle specific things.
+  if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(S)) {
+    if (DRE->refersToEnclosingLocal()) {
+      // FIXME: Handle enums.
+      if (!isa<FunctionDecl>(DRE->getDecl()))
+        BlockDeclRefs.push_back(DRE);
+      if (HasLocalVariableExternalStorage(DRE->getDecl()))
+        BlockDeclRefs.push_back(DRE);
+    }
+  }
+  
+  return;
+}
+
+void RewriteObjC::GetInnerBlockDeclRefExprs(Stmt *S,
+                SmallVectorImpl<DeclRefExpr *> &InnerBlockDeclRefs,
+                llvm::SmallPtrSet<const DeclContext *, 8> &InnerContexts) {
+  for (Stmt::child_range CI = S->children(); CI; ++CI)
+    if (*CI) {
+      if (BlockExpr *CBE = dyn_cast<BlockExpr>(*CI)) {
+        InnerContexts.insert(cast<DeclContext>(CBE->getBlockDecl()));
+        GetInnerBlockDeclRefExprs(CBE->getBody(),
+                                  InnerBlockDeclRefs,
+                                  InnerContexts);
+      }
+      else
+        GetInnerBlockDeclRefExprs(*CI,
+                                  InnerBlockDeclRefs,
+                                  InnerContexts);
+
+    }
+  // Handle specific things.
+  if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(S)) {
+    if (DRE->refersToEnclosingLocal()) {
+      if (!isa<FunctionDecl>(DRE->getDecl()) &&
+          !InnerContexts.count(DRE->getDecl()->getDeclContext()))
+        InnerBlockDeclRefs.push_back(DRE);
+      if (VarDecl *Var = dyn_cast<VarDecl>(DRE->getDecl()))
+        if (Var->isFunctionOrMethodVarDecl())
+          ImportedLocalExternalDecls.insert(Var);
+    }
+  }
+  
+  return;
+}
+
+/// convertFunctionTypeOfBlocks - This routine converts a function type
+/// whose result type may be a block pointer or whose argument type(s)
+/// might be block pointers to an equivalent function type replacing
+/// all block pointers to function pointers.
+QualType RewriteObjC::convertFunctionTypeOfBlocks(const FunctionType *FT) {
+  const FunctionProtoType *FTP = dyn_cast<FunctionProtoType>(FT);
+  // FTP will be null for closures that don't take arguments.
+  // Generate a funky cast.
+  SmallVector<QualType, 8> ArgTypes;
+  QualType Res = FT->getReturnType();
+  bool HasBlockType = convertBlockPointerToFunctionPointer(Res);
+  
+  if (FTP) {
+    for (auto &I : FTP->param_types()) {
+      QualType t = I;
+      // Make sure we convert "t (^)(...)" to "t (*)(...)".
+      if (convertBlockPointerToFunctionPointer(t))
+        HasBlockType = true;
+      ArgTypes.push_back(t);
+    }
+  }
+  QualType FuncType;
+  // FIXME. Does this work if block takes no argument but has a return type
+  // which is of block type?
+  if (HasBlockType)
+    FuncType = getSimpleFunctionType(Res, ArgTypes);
+  else FuncType = QualType(FT, 0);
+  return FuncType;
+}
+
+Stmt *RewriteObjC::SynthesizeBlockCall(CallExpr *Exp, const Expr *BlockExp) {
+  // Navigate to relevant type information.
+  const BlockPointerType *CPT = nullptr;
+
+  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BlockExp)) {
+    CPT = DRE->getType()->getAs<BlockPointerType>();
+  } else if (const MemberExpr *MExpr = dyn_cast<MemberExpr>(BlockExp)) {
+    CPT = MExpr->getType()->getAs<BlockPointerType>();
+  } 
+  else if (const ParenExpr *PRE = dyn_cast<ParenExpr>(BlockExp)) {
+    return SynthesizeBlockCall(Exp, PRE->getSubExpr());
+  }
+  else if (const ImplicitCastExpr *IEXPR = dyn_cast<ImplicitCastExpr>(BlockExp)) 
+    CPT = IEXPR->getType()->getAs<BlockPointerType>();
+  else if (const ConditionalOperator *CEXPR = 
+            dyn_cast<ConditionalOperator>(BlockExp)) {
+    Expr *LHSExp = CEXPR->getLHS();
+    Stmt *LHSStmt = SynthesizeBlockCall(Exp, LHSExp);
+    Expr *RHSExp = CEXPR->getRHS();
+    Stmt *RHSStmt = SynthesizeBlockCall(Exp, RHSExp);
+    Expr *CONDExp = CEXPR->getCond();
+    ConditionalOperator *CondExpr =
+      new (Context) ConditionalOperator(CONDExp,
+                                      SourceLocation(), cast<Expr>(LHSStmt),
+                                      SourceLocation(), cast<Expr>(RHSStmt),
+                                      Exp->getType(), VK_RValue, OK_Ordinary);
+    return CondExpr;
+  } else if (const ObjCIvarRefExpr *IRE = dyn_cast<ObjCIvarRefExpr>(BlockExp)) {
+    CPT = IRE->getType()->getAs<BlockPointerType>();
+  } else if (const PseudoObjectExpr *POE
+               = dyn_cast<PseudoObjectExpr>(BlockExp)) {
+    CPT = POE->getType()->castAs<BlockPointerType>();
+  } else {
+    assert(1 && "RewriteBlockClass: Bad type");
+  }
+  assert(CPT && "RewriteBlockClass: Bad type");
+  const FunctionType *FT = CPT->getPointeeType()->getAs<FunctionType>();
+  assert(FT && "RewriteBlockClass: Bad type");
+  const FunctionProtoType *FTP = dyn_cast<FunctionProtoType>(FT);
+  // FTP will be null for closures that don't take arguments.
+
+  RecordDecl *RD = RecordDecl::Create(*Context, TTK_Struct, TUDecl,
+                                      SourceLocation(), SourceLocation(),
+                                      &Context->Idents.get("__block_impl"));
+  QualType PtrBlock = Context->getPointerType(Context->getTagDeclType(RD));
+
+  // Generate a funky cast.
+  SmallVector<QualType, 8> ArgTypes;
+
+  // Push the block argument type.
+  ArgTypes.push_back(PtrBlock);
+  if (FTP) {
+    for (auto &I : FTP->param_types()) {
+      QualType t = I;
+      // Make sure we convert "t (^)(...)" to "t (*)(...)".
+      if (!convertBlockPointerToFunctionPointer(t))
+        convertToUnqualifiedObjCType(t);
+      ArgTypes.push_back(t);
+    }
+  }
+  // Now do the pointer to function cast.
+  QualType PtrToFuncCastType = getSimpleFunctionType(Exp->getType(), ArgTypes);
+
+  PtrToFuncCastType = Context->getPointerType(PtrToFuncCastType);
+
+  CastExpr *BlkCast = NoTypeInfoCStyleCastExpr(Context, PtrBlock,
+                                               CK_BitCast,
+                                               const_cast<Expr*>(BlockExp));
+  // Don't forget the parens to enforce the proper binding.
+  ParenExpr *PE = new (Context) ParenExpr(SourceLocation(), SourceLocation(),
+                                          BlkCast);
+  //PE->dump();
+
+  FieldDecl *FD = FieldDecl::Create(*Context, nullptr, SourceLocation(),
+                                    SourceLocation(),
+                                    &Context->Idents.get("FuncPtr"),
+                                    Context->VoidPtrTy, nullptr,
+                                    /*BitWidth=*/nullptr, /*Mutable=*/true,
+                                    ICIS_NoInit);
+  MemberExpr *ME = new (Context) MemberExpr(PE, true, FD, SourceLocation(),
+                                            FD->getType(), VK_LValue,
+                                            OK_Ordinary);
+
+  
+  CastExpr *FunkCast = NoTypeInfoCStyleCastExpr(Context, PtrToFuncCastType,
+                                                CK_BitCast, ME);
+  PE = new (Context) ParenExpr(SourceLocation(), SourceLocation(), FunkCast);
+
+  SmallVector<Expr*, 8> BlkExprs;
+  // Add the implicit argument.
+  BlkExprs.push_back(BlkCast);
+  // Add the user arguments.
+  for (CallExpr::arg_iterator I = Exp->arg_begin(),
+       E = Exp->arg_end(); I != E; ++I) {
+    BlkExprs.push_back(*I);
+  }
+  CallExpr *CE = new (Context) CallExpr(*Context, PE, BlkExprs,
+                                        Exp->getType(), VK_RValue,
+                                        SourceLocation());
+  return CE;
+}
+
+// We need to return the rewritten expression to handle cases where the
+// BlockDeclRefExpr is embedded in another expression being rewritten.
+// For example:
+//
+// int main() {
+//    __block Foo *f;
+//    __block int i;
+//
+//    void (^myblock)() = ^() {
+//        [f test]; // f is a BlockDeclRefExpr embedded in a message (which is being rewritten).
+//        i = 77;
+//    };
+//}
+Stmt *RewriteObjC::RewriteBlockDeclRefExpr(DeclRefExpr *DeclRefExp) {
+  // Rewrite the byref variable into BYREFVAR->__forwarding->BYREFVAR 
+  // for each DeclRefExp where BYREFVAR is name of the variable.
+  ValueDecl *VD = DeclRefExp->getDecl();
+  bool isArrow = DeclRefExp->refersToEnclosingLocal();
+
+  FieldDecl *FD = FieldDecl::Create(*Context, nullptr, SourceLocation(),
+                                    SourceLocation(),
+                                    &Context->Idents.get("__forwarding"), 
+                                    Context->VoidPtrTy, nullptr,
+                                    /*BitWidth=*/nullptr, /*Mutable=*/true,
+                                    ICIS_NoInit);
+  MemberExpr *ME = new (Context) MemberExpr(DeclRefExp, isArrow,
+                                            FD, SourceLocation(),
+                                            FD->getType(), VK_LValue,
+                                            OK_Ordinary);
+
+  StringRef Name = VD->getName();
+  FD = FieldDecl::Create(*Context, nullptr, SourceLocation(), SourceLocation(),
+                         &Context->Idents.get(Name), 
+                         Context->VoidPtrTy, nullptr,
+                         /*BitWidth=*/nullptr, /*Mutable=*/true,
+                         ICIS_NoInit);
+  ME = new (Context) MemberExpr(ME, true, FD, SourceLocation(),
+                                DeclRefExp->getType(), VK_LValue, OK_Ordinary);
+  
+  
+  
+  // Need parens to enforce precedence.
+  ParenExpr *PE = new (Context) ParenExpr(DeclRefExp->getExprLoc(), 
+                                          DeclRefExp->getExprLoc(), 
+                                          ME);
+  ReplaceStmt(DeclRefExp, PE);
+  return PE;
+}
+
+// Rewrites the imported local variable V with external storage 
+// (static, extern, etc.) as *V
+//
+Stmt *RewriteObjC::RewriteLocalVariableExternalStorage(DeclRefExpr *DRE) {
+  ValueDecl *VD = DRE->getDecl();
+  if (VarDecl *Var = dyn_cast<VarDecl>(VD))
+    if (!ImportedLocalExternalDecls.count(Var))
+      return DRE;
+  Expr *Exp = new (Context) UnaryOperator(DRE, UO_Deref, DRE->getType(),
+                                          VK_LValue, OK_Ordinary,
+                                          DRE->getLocation());
+  // Need parens to enforce precedence.
+  ParenExpr *PE = new (Context) ParenExpr(SourceLocation(), SourceLocation(), 
+                                          Exp);
+  ReplaceStmt(DRE, PE);
+  return PE;
+}
+
+void RewriteObjC::RewriteCastExpr(CStyleCastExpr *CE) {
+  SourceLocation LocStart = CE->getLParenLoc();
+  SourceLocation LocEnd = CE->getRParenLoc();
+
+  // Need to avoid trying to rewrite synthesized casts.
+  if (LocStart.isInvalid())
+    return;
+  // Need to avoid trying to rewrite casts contained in macros.
+  if (!Rewriter::isRewritable(LocStart) || !Rewriter::isRewritable(LocEnd))
+    return;
+
+  const char *startBuf = SM->getCharacterData(LocStart);
+  const char *endBuf = SM->getCharacterData(LocEnd);
+  QualType QT = CE->getType();
+  const Type* TypePtr = QT->getAs<Type>();
+  if (isa<TypeOfExprType>(TypePtr)) {
+    const TypeOfExprType *TypeOfExprTypePtr = cast<TypeOfExprType>(TypePtr);
+    QT = TypeOfExprTypePtr->getUnderlyingExpr()->getType();
+    std::string TypeAsString = "(";
+    RewriteBlockPointerType(TypeAsString, QT);
+    TypeAsString += ")";
+    ReplaceText(LocStart, endBuf-startBuf+1, TypeAsString);
+    return;
+  }
+  // advance the location to startArgList.
+  const char *argPtr = startBuf;
+
+  while (*argPtr++ && (argPtr < endBuf)) {
+    switch (*argPtr) {
+    case '^':
+      // Replace the '^' with '*'.
+      LocStart = LocStart.getLocWithOffset(argPtr-startBuf);
+      ReplaceText(LocStart, 1, "*");
+      break;
+    }
+  }
+  return;
+}
+
+void RewriteObjC::RewriteBlockPointerFunctionArgs(FunctionDecl *FD) {
+  SourceLocation DeclLoc = FD->getLocation();
+  unsigned parenCount = 0;
+
+  // We have 1 or more arguments that have closure pointers.
+  const char *startBuf = SM->getCharacterData(DeclLoc);
+  const char *startArgList = strchr(startBuf, '(');
+
+  assert((*startArgList == '(') && "Rewriter fuzzy parser confused");
+
+  parenCount++;
+  // advance the location to startArgList.
+  DeclLoc = DeclLoc.getLocWithOffset(startArgList-startBuf);
+  assert((DeclLoc.isValid()) && "Invalid DeclLoc");
+
+  const char *argPtr = startArgList;
+
+  while (*argPtr++ && parenCount) {
+    switch (*argPtr) {
+    case '^':
+      // Replace the '^' with '*'.
+      DeclLoc = DeclLoc.getLocWithOffset(argPtr-startArgList);
+      ReplaceText(DeclLoc, 1, "*");
+      break;
+    case '(':
+      parenCount++;
+      break;
+    case ')':
+      parenCount--;
+      break;
+    }
+  }
+  return;
+}
+
+bool RewriteObjC::PointerTypeTakesAnyBlockArguments(QualType QT) {
+  const FunctionProtoType *FTP;
+  const PointerType *PT = QT->getAs<PointerType>();
+  if (PT) {
+    FTP = PT->getPointeeType()->getAs<FunctionProtoType>();
+  } else {
+    const BlockPointerType *BPT = QT->getAs<BlockPointerType>();
+    assert(BPT && "BlockPointerTypeTakeAnyBlockArguments(): not a block pointer type");
+    FTP = BPT->getPointeeType()->getAs<FunctionProtoType>();
+  }
+  if (FTP) {
+    for (const auto &I : FTP->param_types())
+      if (isTopLevelBlockPointerType(I))
+        return true;
+  }
+  return false;
+}
+
+bool RewriteObjC::PointerTypeTakesAnyObjCQualifiedType(QualType QT) {
+  const FunctionProtoType *FTP;
+  const PointerType *PT = QT->getAs<PointerType>();
+  if (PT) {
+    FTP = PT->getPointeeType()->getAs<FunctionProtoType>();
+  } else {
+    const BlockPointerType *BPT = QT->getAs<BlockPointerType>();
+    assert(BPT && "BlockPointerTypeTakeAnyBlockArguments(): not a block pointer type");
+    FTP = BPT->getPointeeType()->getAs<FunctionProtoType>();
+  }
+  if (FTP) {
+    for (const auto &I : FTP->param_types()) {
+      if (I->isObjCQualifiedIdType())
+        return true;
+      if (I->isObjCObjectPointerType() &&
+          I->getPointeeType()->isObjCQualifiedInterfaceType())
+        return true;
+    }
+        
+  }
+  return false;
+}
+
+void RewriteObjC::GetExtentOfArgList(const char *Name, const char *&LParen,
+                                     const char *&RParen) {
+  const char *argPtr = strchr(Name, '(');
+  assert((*argPtr == '(') && "Rewriter fuzzy parser confused");
+
+  LParen = argPtr; // output the start.
+  argPtr++; // skip past the left paren.
+  unsigned parenCount = 1;
+
+  while (*argPtr && parenCount) {
+    switch (*argPtr) {
+    case '(': parenCount++; break;
+    case ')': parenCount--; break;
+    default: break;
+    }
+    if (parenCount) argPtr++;
+  }
+  assert((*argPtr == ')') && "Rewriter fuzzy parser confused");
+  RParen = argPtr; // output the end
+}
+
+void RewriteObjC::RewriteBlockPointerDecl(NamedDecl *ND) {
+  if (FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
+    RewriteBlockPointerFunctionArgs(FD);
+    return;
+  }
+  // Handle Variables and Typedefs.
+  SourceLocation DeclLoc = ND->getLocation();
+  QualType DeclT;
+  if (VarDecl *VD = dyn_cast<VarDecl>(ND))
+    DeclT = VD->getType();
+  else if (TypedefNameDecl *TDD = dyn_cast<TypedefNameDecl>(ND))
+    DeclT = TDD->getUnderlyingType();
+  else if (FieldDecl *FD = dyn_cast<FieldDecl>(ND))
+    DeclT = FD->getType();
+  else
+    llvm_unreachable("RewriteBlockPointerDecl(): Decl type not yet handled");
+
+  const char *startBuf = SM->getCharacterData(DeclLoc);
+  const char *endBuf = startBuf;
+  // scan backward (from the decl location) for the end of the previous decl.
+  while (*startBuf != '^' && *startBuf != ';' && startBuf != MainFileStart)
+    startBuf--;
+  SourceLocation Start = DeclLoc.getLocWithOffset(startBuf-endBuf);
+  std::string buf;
+  unsigned OrigLength=0;
+  // *startBuf != '^' if we are dealing with a pointer to function that
+  // may take block argument types (which will be handled below).
+  if (*startBuf == '^') {
+    // Replace the '^' with '*', computing a negative offset.
+    buf = '*';
+    startBuf++;
+    OrigLength++;
+  }
+  while (*startBuf != ')') {
+    buf += *startBuf;
+    startBuf++;
+    OrigLength++;
+  }
+  buf += ')';
+  OrigLength++;
+  
+  if (PointerTypeTakesAnyBlockArguments(DeclT) ||
+      PointerTypeTakesAnyObjCQualifiedType(DeclT)) {
+    // Replace the '^' with '*' for arguments.
+    // Replace id<P> with id/*<>*/
+    DeclLoc = ND->getLocation();
+    startBuf = SM->getCharacterData(DeclLoc);
+    const char *argListBegin, *argListEnd;
+    GetExtentOfArgList(startBuf, argListBegin, argListEnd);
+    while (argListBegin < argListEnd) {
+      if (*argListBegin == '^')
+        buf += '*';
+      else if (*argListBegin ==  '<') {
+        buf += "/*"; 
+        buf += *argListBegin++;
+        OrigLength++;
+        while (*argListBegin != '>') {
+          buf += *argListBegin++;
+          OrigLength++;
+        }
+        buf += *argListBegin;
+        buf += "*/";
+      }
+      else
+        buf += *argListBegin;
+      argListBegin++;
+      OrigLength++;
+    }
+    buf += ')';
+    OrigLength++;
+  }
+  ReplaceText(Start, OrigLength, buf);
+  
+  return;
+}
+
+
+/// SynthesizeByrefCopyDestroyHelper - This routine synthesizes:
+/// void __Block_byref_id_object_copy(struct Block_byref_id_object *dst,
+///                    struct Block_byref_id_object *src) {
+///  _Block_object_assign (&_dest->object, _src->object, 
+///                        BLOCK_BYREF_CALLER | BLOCK_FIELD_IS_OBJECT
+///                        [|BLOCK_FIELD_IS_WEAK]) // object
+///  _Block_object_assign(&_dest->object, _src->object, 
+///                       BLOCK_BYREF_CALLER | BLOCK_FIELD_IS_BLOCK
+///                       [|BLOCK_FIELD_IS_WEAK]) // block
+/// }
+/// And:
+/// void __Block_byref_id_object_dispose(struct Block_byref_id_object *_src) {
+///  _Block_object_dispose(_src->object, 
+///                        BLOCK_BYREF_CALLER | BLOCK_FIELD_IS_OBJECT
+///                        [|BLOCK_FIELD_IS_WEAK]) // object
+///  _Block_object_dispose(_src->object, 
+///                         BLOCK_BYREF_CALLER | BLOCK_FIELD_IS_BLOCK
+///                         [|BLOCK_FIELD_IS_WEAK]) // block
+/// }
+
+std::string RewriteObjC::SynthesizeByrefCopyDestroyHelper(VarDecl *VD,
+                                                          int flag) {
+  std::string S;
+  if (CopyDestroyCache.count(flag))
+    return S;
+  CopyDestroyCache.insert(flag);
+  S = "static void __Block_byref_id_object_copy_";
+  S += utostr(flag);
+  S += "(void *dst, void *src) {\n";
+  
+  // offset into the object pointer is computed as:
+  // void * + void* + int + int + void* + void *
+  unsigned IntSize = 
+  static_cast<unsigned>(Context->getTypeSize(Context->IntTy));
+  unsigned VoidPtrSize = 
+  static_cast<unsigned>(Context->getTypeSize(Context->VoidPtrTy));
+  
+  unsigned offset = (VoidPtrSize*4 + IntSize + IntSize)/Context->getCharWidth();
+  S += " _Block_object_assign((char*)dst + ";
+  S += utostr(offset);
+  S += ", *(void * *) ((char*)src + ";
+  S += utostr(offset);
+  S += "), ";
+  S += utostr(flag);
+  S += ");\n}\n";
+  
+  S += "static void __Block_byref_id_object_dispose_";
+  S += utostr(flag);
+  S += "(void *src) {\n";
+  S += " _Block_object_dispose(*(void * *) ((char*)src + ";
+  S += utostr(offset);
+  S += "), ";
+  S += utostr(flag);
+  S += ");\n}\n";
+  return S;
+}
+
+/// RewriteByRefVar - For each __block typex ND variable this routine transforms
+/// the declaration into:
+/// struct __Block_byref_ND {
+/// void *__isa;                  // NULL for everything except __weak pointers
+/// struct __Block_byref_ND *__forwarding;
+/// int32_t __flags;
+/// int32_t __size;
+/// void *__Block_byref_id_object_copy; // If variable is __block ObjC object
+/// void *__Block_byref_id_object_dispose; // If variable is __block ObjC object
+/// typex ND;
+/// };
+///
+/// It then replaces declaration of ND variable with:
+/// struct __Block_byref_ND ND = {__isa=0B, __forwarding=&ND, __flags=some_flag, 
+///                               __size=sizeof(struct __Block_byref_ND), 
+///                               ND=initializer-if-any};
+///
+///
+void RewriteObjC::RewriteByRefVar(VarDecl *ND) {
+  // Insert declaration for the function in which block literal is
+  // used.
+  if (CurFunctionDeclToDeclareForBlock)
+    RewriteBlockLiteralFunctionDecl(CurFunctionDeclToDeclareForBlock);
+  int flag = 0;
+  int isa = 0;
+  SourceLocation DeclLoc = ND->getTypeSpecStartLoc();
+  if (DeclLoc.isInvalid())
+    // If type location is missing, it is because of missing type (a warning).
+    // Use variable's location which is good for this case.
+    DeclLoc = ND->getLocation();
+  const char *startBuf = SM->getCharacterData(DeclLoc);
+  SourceLocation X = ND->getLocEnd();
+  X = SM->getExpansionLoc(X);
+  const char *endBuf = SM->getCharacterData(X);
+  std::string Name(ND->getNameAsString());
+  std::string ByrefType;
+  RewriteByRefString(ByrefType, Name, ND, true);
+  ByrefType += " {\n";
+  ByrefType += "  void *__isa;\n";
+  RewriteByRefString(ByrefType, Name, ND);
+  ByrefType += " *__forwarding;\n";
+  ByrefType += " int __flags;\n";
+  ByrefType += " int __size;\n";
+  // Add void *__Block_byref_id_object_copy; 
+  // void *__Block_byref_id_object_dispose; if needed.
+  QualType Ty = ND->getType();
+  bool HasCopyAndDispose = Context->BlockRequiresCopying(Ty, ND);
+  if (HasCopyAndDispose) {
+    ByrefType += " void (*__Block_byref_id_object_copy)(void*, void*);\n";
+    ByrefType += " void (*__Block_byref_id_object_dispose)(void*);\n";
+  }
+
+  QualType T = Ty;
+  (void)convertBlockPointerToFunctionPointer(T);
+  T.getAsStringInternal(Name, Context->getPrintingPolicy());
+    
+  ByrefType += " " + Name + ";\n";
+  ByrefType += "};\n";
+  // Insert this type in global scope. It is needed by helper function.
+  SourceLocation FunLocStart;
+  if (CurFunctionDef)
+     FunLocStart = CurFunctionDef->getTypeSpecStartLoc();
+  else {
+    assert(CurMethodDef && "RewriteByRefVar - CurMethodDef is null");
+    FunLocStart = CurMethodDef->getLocStart();
+  }
+  InsertText(FunLocStart, ByrefType);
+  if (Ty.isObjCGCWeak()) {
+    flag |= BLOCK_FIELD_IS_WEAK;
+    isa = 1;
+  }
+  
+  if (HasCopyAndDispose) {
+    flag = BLOCK_BYREF_CALLER;
+    QualType Ty = ND->getType();
+    // FIXME. Handle __weak variable (BLOCK_FIELD_IS_WEAK) as well.
+    if (Ty->isBlockPointerType())
+      flag |= BLOCK_FIELD_IS_BLOCK;
+    else
+      flag |= BLOCK_FIELD_IS_OBJECT;
+    std::string HF = SynthesizeByrefCopyDestroyHelper(ND, flag);
+    if (!HF.empty())
+      InsertText(FunLocStart, HF);
+  }
+  
+  // struct __Block_byref_ND ND = 
+  // {0, &ND, some_flag, __size=sizeof(struct __Block_byref_ND), 
+  //  initializer-if-any};
+  bool hasInit = (ND->getInit() != nullptr);
+  unsigned flags = 0;
+  if (HasCopyAndDispose)
+    flags |= BLOCK_HAS_COPY_DISPOSE;
+  Name = ND->getNameAsString();
+  ByrefType.clear();
+  RewriteByRefString(ByrefType, Name, ND);
+  std::string ForwardingCastType("(");
+  ForwardingCastType += ByrefType + " *)";
+  if (!hasInit) {
+    ByrefType += " " + Name + " = {(void*)";
+    ByrefType += utostr(isa);
+    ByrefType += "," +  ForwardingCastType + "&" + Name + ", ";
+    ByrefType += utostr(flags);
+    ByrefType += ", ";
+    ByrefType += "sizeof(";
+    RewriteByRefString(ByrefType, Name, ND);
+    ByrefType += ")";
+    if (HasCopyAndDispose) {
+      ByrefType += ", __Block_byref_id_object_copy_";
+      ByrefType += utostr(flag);
+      ByrefType += ", __Block_byref_id_object_dispose_";
+      ByrefType += utostr(flag);
+    }
+    ByrefType += "};\n";
+    unsigned nameSize = Name.size();
+    // for block or function pointer declaration. Name is aleady
+    // part of the declaration.
+    if (Ty->isBlockPointerType() || Ty->isFunctionPointerType())
+      nameSize = 1;
+    ReplaceText(DeclLoc, endBuf-startBuf+nameSize, ByrefType);
+  }
+  else {
+    SourceLocation startLoc;
+    Expr *E = ND->getInit();
+    if (const CStyleCastExpr *ECE = dyn_cast<CStyleCastExpr>(E))
+      startLoc = ECE->getLParenLoc();
+    else
+      startLoc = E->getLocStart();
+    startLoc = SM->getExpansionLoc(startLoc);
+    endBuf = SM->getCharacterData(startLoc);
+    ByrefType += " " + Name;
+    ByrefType += " = {(void*)";
+    ByrefType += utostr(isa);
+    ByrefType += "," +  ForwardingCastType + "&" + Name + ", ";
+    ByrefType += utostr(flags);
+    ByrefType += ", ";
+    ByrefType += "sizeof(";
+    RewriteByRefString(ByrefType, Name, ND);
+    ByrefType += "), ";
+    if (HasCopyAndDispose) {
+      ByrefType += "__Block_byref_id_object_copy_";
+      ByrefType += utostr(flag);
+      ByrefType += ", __Block_byref_id_object_dispose_";
+      ByrefType += utostr(flag);
+      ByrefType += ", ";
+    }
+    ReplaceText(DeclLoc, endBuf-startBuf, ByrefType);
+    
+    // Complete the newly synthesized compound expression by inserting a right
+    // curly brace before the end of the declaration.
+    // FIXME: This approach avoids rewriting the initializer expression. It
+    // also assumes there is only one declarator. For example, the following
+    // isn't currently supported by this routine (in general):
+    // 
+    // double __block BYREFVAR = 1.34, BYREFVAR2 = 1.37;
+    //
+    const char *startInitializerBuf = SM->getCharacterData(startLoc);
+    const char *semiBuf = strchr(startInitializerBuf, ';');
+    assert((*semiBuf == ';') && "RewriteByRefVar: can't find ';'");
+    SourceLocation semiLoc =
+      startLoc.getLocWithOffset(semiBuf-startInitializerBuf);
+
+    InsertText(semiLoc, "}");
+  }
+  return;
+}
+
+void RewriteObjC::CollectBlockDeclRefInfo(BlockExpr *Exp) {
+  // Add initializers for any closure decl refs.
+  GetBlockDeclRefExprs(Exp->getBody());
+  if (BlockDeclRefs.size()) {
+    // Unique all "by copy" declarations.
+    for (unsigned i = 0; i < BlockDeclRefs.size(); i++)
+      if (!BlockDeclRefs[i]->getDecl()->hasAttr<BlocksAttr>()) {
+        if (!BlockByCopyDeclsPtrSet.count(BlockDeclRefs[i]->getDecl())) {
+          BlockByCopyDeclsPtrSet.insert(BlockDeclRefs[i]->getDecl());
+          BlockByCopyDecls.push_back(BlockDeclRefs[i]->getDecl());
+        }
+      }
+    // Unique all "by ref" declarations.
+    for (unsigned i = 0; i < BlockDeclRefs.size(); i++)
+      if (BlockDeclRefs[i]->getDecl()->hasAttr<BlocksAttr>()) {
+        if (!BlockByRefDeclsPtrSet.count(BlockDeclRefs[i]->getDecl())) {
+          BlockByRefDeclsPtrSet.insert(BlockDeclRefs[i]->getDecl());
+          BlockByRefDecls.push_back(BlockDeclRefs[i]->getDecl());
+        }
+      }
+    // Find any imported blocks...they will need special attention.
+    for (unsigned i = 0; i < BlockDeclRefs.size(); i++)
+      if (BlockDeclRefs[i]->getDecl()->hasAttr<BlocksAttr>() ||
+          BlockDeclRefs[i]->getType()->isObjCObjectPointerType() || 
+          BlockDeclRefs[i]->getType()->isBlockPointerType())
+        ImportedBlockDecls.insert(BlockDeclRefs[i]->getDecl());
+  }
+}
+
+FunctionDecl *RewriteObjC::SynthBlockInitFunctionDecl(StringRef name) {
+  IdentifierInfo *ID = &Context->Idents.get(name);
+  QualType FType = Context->getFunctionNoProtoType(Context->VoidPtrTy);
+  return FunctionDecl::Create(*Context, TUDecl, SourceLocation(),
+                              SourceLocation(), ID, FType, nullptr, SC_Extern,
+                              false, false);
+}
+
+Stmt *RewriteObjC::SynthBlockInitExpr(BlockExpr *Exp,
+                     const SmallVectorImpl<DeclRefExpr *> &InnerBlockDeclRefs) {
+  const BlockDecl *block = Exp->getBlockDecl();
+  Blocks.push_back(Exp);
+
+  CollectBlockDeclRefInfo(Exp);
+  
+  // Add inner imported variables now used in current block.
+ int countOfInnerDecls = 0;
+  if (!InnerBlockDeclRefs.empty()) {
+    for (unsigned i = 0; i < InnerBlockDeclRefs.size(); i++) {
+      DeclRefExpr *Exp = InnerBlockDeclRefs[i];
+      ValueDecl *VD = Exp->getDecl();
+      if (!VD->hasAttr<BlocksAttr>() && !BlockByCopyDeclsPtrSet.count(VD)) {
+      // We need to save the copied-in variables in nested
+      // blocks because it is needed at the end for some of the API generations.
+      // See SynthesizeBlockLiterals routine.
+        InnerDeclRefs.push_back(Exp); countOfInnerDecls++;
+        BlockDeclRefs.push_back(Exp);
+        BlockByCopyDeclsPtrSet.insert(VD);
+        BlockByCopyDecls.push_back(VD);
+      }
+      if (VD->hasAttr<BlocksAttr>() && !BlockByRefDeclsPtrSet.count(VD)) {
+        InnerDeclRefs.push_back(Exp); countOfInnerDecls++;
+        BlockDeclRefs.push_back(Exp);
+        BlockByRefDeclsPtrSet.insert(VD);
+        BlockByRefDecls.push_back(VD);
+      }
+    }
+    // Find any imported blocks...they will need special attention.
+    for (unsigned i = 0; i < InnerBlockDeclRefs.size(); i++)
+      if (InnerBlockDeclRefs[i]->getDecl()->hasAttr<BlocksAttr>() ||
+          InnerBlockDeclRefs[i]->getType()->isObjCObjectPointerType() || 
+          InnerBlockDeclRefs[i]->getType()->isBlockPointerType())
+        ImportedBlockDecls.insert(InnerBlockDeclRefs[i]->getDecl());
+  }
+  InnerDeclRefsCount.push_back(countOfInnerDecls);
+  
+  std::string FuncName;
+
+  if (CurFunctionDef)
+    FuncName = CurFunctionDef->getNameAsString();
+  else if (CurMethodDef)
+    BuildUniqueMethodName(FuncName, CurMethodDef);
+  else if (GlobalVarDecl)
+    FuncName = std::string(GlobalVarDecl->getNameAsString());
+
+  std::string BlockNumber = utostr(Blocks.size()-1);
+
+  std::string Tag = "__" + FuncName + "_block_impl_" + BlockNumber;
+  std::string Func = "__" + FuncName + "_block_func_" + BlockNumber;
+
+  // Get a pointer to the function type so we can cast appropriately.
+  QualType BFT = convertFunctionTypeOfBlocks(Exp->getFunctionType());
+  QualType FType = Context->getPointerType(BFT);
+
+  FunctionDecl *FD;
+  Expr *NewRep;
+
+  // Simulate a constructor call...
+  FD = SynthBlockInitFunctionDecl(Tag);
+  DeclRefExpr *DRE = new (Context) DeclRefExpr(FD, false, FType, VK_RValue,
+                                               SourceLocation());
+
+  SmallVector<Expr*, 4> InitExprs;
+
+  // Initialize the block function.
+  FD = SynthBlockInitFunctionDecl(Func);
+  DeclRefExpr *Arg = new (Context) DeclRefExpr(FD, false, FD->getType(),
+                                               VK_LValue, SourceLocation());
+  CastExpr *castExpr = NoTypeInfoCStyleCastExpr(Context, Context->VoidPtrTy,
+                                                CK_BitCast, Arg);
+  InitExprs.push_back(castExpr);
+
+  // Initialize the block descriptor.
+  std::string DescData = "__" + FuncName + "_block_desc_" + BlockNumber + "_DATA";
+
+  VarDecl *NewVD = VarDecl::Create(*Context, TUDecl,
+                                   SourceLocation(), SourceLocation(),
+                                   &Context->Idents.get(DescData.c_str()),
+                                   Context->VoidPtrTy, nullptr,
+                                   SC_Static);
+  UnaryOperator *DescRefExpr =
+    new (Context) UnaryOperator(new (Context) DeclRefExpr(NewVD, false,
+                                                          Context->VoidPtrTy,
+                                                          VK_LValue,
+                                                          SourceLocation()), 
+                                UO_AddrOf,
+                                Context->getPointerType(Context->VoidPtrTy), 
+                                VK_RValue, OK_Ordinary,
+                                SourceLocation());
+  InitExprs.push_back(DescRefExpr); 
+  
+  // Add initializers for any closure decl refs.
+  if (BlockDeclRefs.size()) {
+    Expr *Exp;
+    // Output all "by copy" declarations.
+    for (SmallVectorImpl<ValueDecl *>::iterator I = BlockByCopyDecls.begin(),
+         E = BlockByCopyDecls.end(); I != E; ++I) {
+      if (isObjCType((*I)->getType())) {
+        // FIXME: Conform to ABI ([[obj retain] autorelease]).
+        FD = SynthBlockInitFunctionDecl((*I)->getName());
+        Exp = new (Context) DeclRefExpr(FD, false, FD->getType(), VK_LValue,
+                                        SourceLocation());
+        if (HasLocalVariableExternalStorage(*I)) {
+          QualType QT = (*I)->getType();
+          QT = Context->getPointerType(QT);
+          Exp = new (Context) UnaryOperator(Exp, UO_AddrOf, QT, VK_RValue,
+                                            OK_Ordinary, SourceLocation());
+        }
+      } else if (isTopLevelBlockPointerType((*I)->getType())) {
+        FD = SynthBlockInitFunctionDecl((*I)->getName());
+        Arg = new (Context) DeclRefExpr(FD, false, FD->getType(), VK_LValue,
+                                        SourceLocation());
+        Exp = NoTypeInfoCStyleCastExpr(Context, Context->VoidPtrTy,
+                                       CK_BitCast, Arg);
+      } else {
+        FD = SynthBlockInitFunctionDecl((*I)->getName());
+        Exp = new (Context) DeclRefExpr(FD, false, FD->getType(), VK_LValue,
+                                        SourceLocation());
+        if (HasLocalVariableExternalStorage(*I)) {
+          QualType QT = (*I)->getType();
+          QT = Context->getPointerType(QT);
+          Exp = new (Context) UnaryOperator(Exp, UO_AddrOf, QT, VK_RValue,
+                                            OK_Ordinary, SourceLocation());
+        }
+        
+      }
+      InitExprs.push_back(Exp);
+    }
+    // Output all "by ref" declarations.
+    for (SmallVectorImpl<ValueDecl *>::iterator I = BlockByRefDecls.begin(),
+         E = BlockByRefDecls.end(); I != E; ++I) {
+      ValueDecl *ND = (*I);
+      std::string Name(ND->getNameAsString());
+      std::string RecName;
+      RewriteByRefString(RecName, Name, ND, true);
+      IdentifierInfo *II = &Context->Idents.get(RecName.c_str() 
+                                                + sizeof("struct"));
+      RecordDecl *RD = RecordDecl::Create(*Context, TTK_Struct, TUDecl,
+                                          SourceLocation(), SourceLocation(),
+                                          II);
+      assert(RD && "SynthBlockInitExpr(): Can't find RecordDecl");
+      QualType castT = Context->getPointerType(Context->getTagDeclType(RD));
+      
+      FD = SynthBlockInitFunctionDecl((*I)->getName());
+      Exp = new (Context) DeclRefExpr(FD, false, FD->getType(), VK_LValue,
+                                      SourceLocation());
+      bool isNestedCapturedVar = false;
+      if (block)
+        for (const auto &CI : block->captures()) {
+          const VarDecl *variable = CI.getVariable();
+          if (variable == ND && CI.isNested()) {
+            assert (CI.isByRef() && 
+                    "SynthBlockInitExpr - captured block variable is not byref");
+            isNestedCapturedVar = true;
+            break;
+          }
+        }
+      // captured nested byref variable has its address passed. Do not take
+      // its address again.
+      if (!isNestedCapturedVar)
+          Exp = new (Context) UnaryOperator(Exp, UO_AddrOf,
+                                     Context->getPointerType(Exp->getType()),
+                                     VK_RValue, OK_Ordinary, SourceLocation());
+      Exp = NoTypeInfoCStyleCastExpr(Context, castT, CK_BitCast, Exp);
+      InitExprs.push_back(Exp);
+    }
+  }
+  if (ImportedBlockDecls.size()) {
+    // generate BLOCK_HAS_COPY_DISPOSE(have helper funcs) | BLOCK_HAS_DESCRIPTOR
+    int flag = (BLOCK_HAS_COPY_DISPOSE | BLOCK_HAS_DESCRIPTOR);
+    unsigned IntSize = 
+      static_cast<unsigned>(Context->getTypeSize(Context->IntTy));
+    Expr *FlagExp = IntegerLiteral::Create(*Context, llvm::APInt(IntSize, flag), 
+                                           Context->IntTy, SourceLocation());
+    InitExprs.push_back(FlagExp);
+  }
+  NewRep = new (Context) CallExpr(*Context, DRE, InitExprs,
+                                  FType, VK_LValue, SourceLocation());
+  NewRep = new (Context) UnaryOperator(NewRep, UO_AddrOf,
+                             Context->getPointerType(NewRep->getType()),
+                             VK_RValue, OK_Ordinary, SourceLocation());
+  NewRep = NoTypeInfoCStyleCastExpr(Context, FType, CK_BitCast,
+                                    NewRep);
+  BlockDeclRefs.clear();
+  BlockByRefDecls.clear();
+  BlockByRefDeclsPtrSet.clear();
+  BlockByCopyDecls.clear();
+  BlockByCopyDeclsPtrSet.clear();
+  ImportedBlockDecls.clear();
+  return NewRep;
+}
+
+bool RewriteObjC::IsDeclStmtInForeachHeader(DeclStmt *DS) {
+  if (const ObjCForCollectionStmt * CS = 
+      dyn_cast<ObjCForCollectionStmt>(Stmts.back()))
+        return CS->getElement() == DS;
+  return false;
+}
+
+//===----------------------------------------------------------------------===//
+// Function Body / Expression rewriting
+//===----------------------------------------------------------------------===//
+
+Stmt *RewriteObjC::RewriteFunctionBodyOrGlobalInitializer(Stmt *S) {
+  if (isa<SwitchStmt>(S) || isa<WhileStmt>(S) ||
+      isa<DoStmt>(S) || isa<ForStmt>(S))
+    Stmts.push_back(S);
+  else if (isa<ObjCForCollectionStmt>(S)) {
+    Stmts.push_back(S);
+    ObjCBcLabelNo.push_back(++BcLabelCount);
+  }
+
+  // Pseudo-object operations and ivar references need special
+  // treatment because we're going to recursively rewrite them.
+  if (PseudoObjectExpr *PseudoOp = dyn_cast<PseudoObjectExpr>(S)) {
+    if (isa<BinaryOperator>(PseudoOp->getSyntacticForm())) {
+      return RewritePropertyOrImplicitSetter(PseudoOp);
+    } else {
+      return RewritePropertyOrImplicitGetter(PseudoOp);
+    }
+  } else if (ObjCIvarRefExpr *IvarRefExpr = dyn_cast<ObjCIvarRefExpr>(S)) {
+    return RewriteObjCIvarRefExpr(IvarRefExpr);
+  }
+
+  SourceRange OrigStmtRange = S->getSourceRange();
+
+  // Perform a bottom up rewrite of all children.
+  for (Stmt::child_range CI = S->children(); CI; ++CI)
+    if (*CI) {
+      Stmt *childStmt = (*CI);
+      Stmt *newStmt = RewriteFunctionBodyOrGlobalInitializer(childStmt);
+      if (newStmt) {
+        *CI = newStmt;
+      }
+    }
+
+  if (BlockExpr *BE = dyn_cast<BlockExpr>(S)) {
+    SmallVector<DeclRefExpr *, 8> InnerBlockDeclRefs;
+    llvm::SmallPtrSet<const DeclContext *, 8> InnerContexts;
+    InnerContexts.insert(BE->getBlockDecl());
+    ImportedLocalExternalDecls.clear();
+    GetInnerBlockDeclRefExprs(BE->getBody(),
+                              InnerBlockDeclRefs, InnerContexts);
+    // Rewrite the block body in place.
+    Stmt *SaveCurrentBody = CurrentBody;
+    CurrentBody = BE->getBody();
+    PropParentMap = nullptr;
+    // block literal on rhs of a property-dot-sytax assignment
+    // must be replaced by its synthesize ast so getRewrittenText
+    // works as expected. In this case, what actually ends up on RHS
+    // is the blockTranscribed which is the helper function for the
+    // block literal; as in: self.c = ^() {[ace ARR];};
+    bool saveDisableReplaceStmt = DisableReplaceStmt;
+    DisableReplaceStmt = false;
+    RewriteFunctionBodyOrGlobalInitializer(BE->getBody());
+    DisableReplaceStmt = saveDisableReplaceStmt;
+    CurrentBody = SaveCurrentBody;
+    PropParentMap = nullptr;
+    ImportedLocalExternalDecls.clear();
+    // Now we snarf the rewritten text and stash it away for later use.
+    std::string Str = Rewrite.getRewrittenText(BE->getSourceRange());
+    RewrittenBlockExprs[BE] = Str;
+
+    Stmt *blockTranscribed = SynthBlockInitExpr(BE, InnerBlockDeclRefs);
+                            
+    //blockTranscribed->dump();
+    ReplaceStmt(S, blockTranscribed);
+    return blockTranscribed;
+  }
+  // Handle specific things.
+  if (ObjCEncodeExpr *AtEncode = dyn_cast<ObjCEncodeExpr>(S))
+    return RewriteAtEncode(AtEncode);
+
+  if (ObjCSelectorExpr *AtSelector = dyn_cast<ObjCSelectorExpr>(S))
+    return RewriteAtSelector(AtSelector);
+
+  if (ObjCStringLiteral *AtString = dyn_cast<ObjCStringLiteral>(S))
+    return RewriteObjCStringLiteral(AtString);
+
+  if (ObjCMessageExpr *MessExpr = dyn_cast<ObjCMessageExpr>(S)) {
+#if 0
+    // Before we rewrite it, put the original message expression in a comment.
+    SourceLocation startLoc = MessExpr->getLocStart();
+    SourceLocation endLoc = MessExpr->getLocEnd();
+
+    const char *startBuf = SM->getCharacterData(startLoc);
+    const char *endBuf = SM->getCharacterData(endLoc);
+
+    std::string messString;
+    messString += "// ";
+    messString.append(startBuf, endBuf-startBuf+1);
+    messString += "\n";
+
+    // FIXME: Missing definition of
+    // InsertText(clang::SourceLocation, char const*, unsigned int).
+    // InsertText(startLoc, messString.c_str(), messString.size());
+    // Tried this, but it didn't work either...
+    // ReplaceText(startLoc, 0, messString.c_str(), messString.size());
+#endif
+    return RewriteMessageExpr(MessExpr);
+  }
+
+  if (ObjCAtTryStmt *StmtTry = dyn_cast<ObjCAtTryStmt>(S))
+    return RewriteObjCTryStmt(StmtTry);
+
+  if (ObjCAtSynchronizedStmt *StmtTry = dyn_cast<ObjCAtSynchronizedStmt>(S))
+    return RewriteObjCSynchronizedStmt(StmtTry);
+
+  if (ObjCAtThrowStmt *StmtThrow = dyn_cast<ObjCAtThrowStmt>(S))
+    return RewriteObjCThrowStmt(StmtThrow);
+
+  if (ObjCProtocolExpr *ProtocolExp = dyn_cast<ObjCProtocolExpr>(S))
+    return RewriteObjCProtocolExpr(ProtocolExp);
+
+  if (ObjCForCollectionStmt *StmtForCollection =
+        dyn_cast<ObjCForCollectionStmt>(S))
+    return RewriteObjCForCollectionStmt(StmtForCollection,
+                                        OrigStmtRange.getEnd());
+  if (BreakStmt *StmtBreakStmt =
+      dyn_cast<BreakStmt>(S))
+    return RewriteBreakStmt(StmtBreakStmt);
+  if (ContinueStmt *StmtContinueStmt =
+      dyn_cast<ContinueStmt>(S))
+    return RewriteContinueStmt(StmtContinueStmt);
+
+  // Need to check for protocol refs (id <P>, Foo <P> *) in variable decls
+  // and cast exprs.
+  if (DeclStmt *DS = dyn_cast<DeclStmt>(S)) {
+    // FIXME: What we're doing here is modifying the type-specifier that
+    // precedes the first Decl.  In the future the DeclGroup should have
+    // a separate type-specifier that we can rewrite.
+    // NOTE: We need to avoid rewriting the DeclStmt if it is within
+    // the context of an ObjCForCollectionStmt. For example:
+    //   NSArray *someArray;
+    //   for (id <FooProtocol> index in someArray) ;
+    // This is because RewriteObjCForCollectionStmt() does textual rewriting 
+    // and it depends on the original text locations/positions.
+    if (Stmts.empty() || !IsDeclStmtInForeachHeader(DS))
+      RewriteObjCQualifiedInterfaceTypes(*DS->decl_begin());
+
+    // Blocks rewrite rules.
+    for (auto *SD : DS->decls()) {
+      if (ValueDecl *ND = dyn_cast<ValueDecl>(SD)) {
+        if (isTopLevelBlockPointerType(ND->getType()))
+          RewriteBlockPointerDecl(ND);
+        else if (ND->getType()->isFunctionPointerType())
+          CheckFunctionPointerDecl(ND->getType(), ND);
+        if (VarDecl *VD = dyn_cast<VarDecl>(SD)) {
+          if (VD->hasAttr<BlocksAttr>()) {
+            static unsigned uniqueByrefDeclCount = 0;
+            assert(!BlockByRefDeclNo.count(ND) &&
+              "RewriteFunctionBodyOrGlobalInitializer: Duplicate byref decl");
+            BlockByRefDeclNo[ND] = uniqueByrefDeclCount++;
+            RewriteByRefVar(VD);
+          }
+          else           
+            RewriteTypeOfDecl(VD);
+        }
+      }
+      if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(SD)) {
+        if (isTopLevelBlockPointerType(TD->getUnderlyingType()))
+          RewriteBlockPointerDecl(TD);
+        else if (TD->getUnderlyingType()->isFunctionPointerType())
+          CheckFunctionPointerDecl(TD->getUnderlyingType(), TD);
+      }
+    }
+  }
+
+  if (CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(S))
+    RewriteObjCQualifiedInterfaceTypes(CE);
+
+  if (isa<SwitchStmt>(S) || isa<WhileStmt>(S) ||
+      isa<DoStmt>(S) || isa<ForStmt>(S)) {
+    assert(!Stmts.empty() && "Statement stack is empty");
+    assert ((isa<SwitchStmt>(Stmts.back()) || isa<WhileStmt>(Stmts.back()) ||
+             isa<DoStmt>(Stmts.back()) || isa<ForStmt>(Stmts.back()))
+            && "Statement stack mismatch");
+    Stmts.pop_back();
+  }
+  // Handle blocks rewriting.
+  if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(S)) {
+    ValueDecl *VD = DRE->getDecl(); 
+    if (VD->hasAttr<BlocksAttr>())
+      return RewriteBlockDeclRefExpr(DRE);
+    if (HasLocalVariableExternalStorage(VD))
+      return RewriteLocalVariableExternalStorage(DRE);
+  }
+  
+  if (CallExpr *CE = dyn_cast<CallExpr>(S)) {
+    if (CE->getCallee()->getType()->isBlockPointerType()) {
+      Stmt *BlockCall = SynthesizeBlockCall(CE, CE->getCallee());
+      ReplaceStmt(S, BlockCall);
+      return BlockCall;
+    }
+  }
+  if (CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(S)) {
+    RewriteCastExpr(CE);
+  }
+#if 0
+  if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(S)) {
+    CastExpr *Replacement = new (Context) CastExpr(ICE->getType(),
+                                                   ICE->getSubExpr(),
+                                                   SourceLocation());
+    // Get the new text.
+    std::string SStr;
+    llvm::raw_string_ostream Buf(SStr);
+    Replacement->printPretty(Buf);
+    const std::string &Str = Buf.str();
+
+    printf("CAST = %s\n", &Str[0]);
+    InsertText(ICE->getSubExpr()->getLocStart(), &Str[0], Str.size());
+    delete S;
+    return Replacement;
+  }
+#endif
+  // Return this stmt unmodified.
+  return S;
+}
+
+void RewriteObjC::RewriteRecordBody(RecordDecl *RD) {
+  for (auto *FD : RD->fields()) {
+    if (isTopLevelBlockPointerType(FD->getType()))
+      RewriteBlockPointerDecl(FD);
+    if (FD->getType()->isObjCQualifiedIdType() ||
+        FD->getType()->isObjCQualifiedInterfaceType())
+      RewriteObjCQualifiedInterfaceTypes(FD);
+  }
+}
+
+/// HandleDeclInMainFile - This is called for each top-level decl defined in the
+/// main file of the input.
+void RewriteObjC::HandleDeclInMainFile(Decl *D) {
+  switch (D->getKind()) {
+    case Decl::Function: {
+      FunctionDecl *FD = cast<FunctionDecl>(D);
+      if (FD->isOverloadedOperator())
+        return;
+
+      // Since function prototypes don't have ParmDecl's, we check the function
+      // prototype. This enables us to rewrite function declarations and
+      // definitions using the same code.
+      RewriteBlocksInFunctionProtoType(FD->getType(), FD);
+
+      if (!FD->isThisDeclarationADefinition())
+        break;
+
+      // FIXME: If this should support Obj-C++, support CXXTryStmt
+      if (CompoundStmt *Body = dyn_cast_or_null<CompoundStmt>(FD->getBody())) {
+        CurFunctionDef = FD;
+        CurFunctionDeclToDeclareForBlock = FD;
+        CurrentBody = Body;
+        Body =
+        cast_or_null<CompoundStmt>(RewriteFunctionBodyOrGlobalInitializer(Body));
+        FD->setBody(Body);
+        CurrentBody = nullptr;
+        if (PropParentMap) {
+          delete PropParentMap;
+          PropParentMap = nullptr;
+        }
+        // This synthesizes and inserts the block "impl" struct, invoke function,
+        // and any copy/dispose helper functions.
+        InsertBlockLiteralsWithinFunction(FD);
+        CurFunctionDef = nullptr;
+        CurFunctionDeclToDeclareForBlock = nullptr;
+      }
+      break;
+    }
+    case Decl::ObjCMethod: {
+      ObjCMethodDecl *MD = cast<ObjCMethodDecl>(D);
+      if (CompoundStmt *Body = MD->getCompoundBody()) {
+        CurMethodDef = MD;
+        CurrentBody = Body;
+        Body =
+          cast_or_null<CompoundStmt>(RewriteFunctionBodyOrGlobalInitializer(Body));
+        MD->setBody(Body);
+        CurrentBody = nullptr;
+        if (PropParentMap) {
+          delete PropParentMap;
+          PropParentMap = nullptr;
+        }
+        InsertBlockLiteralsWithinMethod(MD);
+        CurMethodDef = nullptr;
+      }
+      break;
+    }
+    case Decl::ObjCImplementation: {
+      ObjCImplementationDecl *CI = cast<ObjCImplementationDecl>(D);
+      ClassImplementation.push_back(CI);
+      break;
+    }
+    case Decl::ObjCCategoryImpl: {
+      ObjCCategoryImplDecl *CI = cast<ObjCCategoryImplDecl>(D);
+      CategoryImplementation.push_back(CI);
+      break;
+    }
+    case Decl::Var: {
+      VarDecl *VD = cast<VarDecl>(D);
+      RewriteObjCQualifiedInterfaceTypes(VD);
+      if (isTopLevelBlockPointerType(VD->getType()))
+        RewriteBlockPointerDecl(VD);
+      else if (VD->getType()->isFunctionPointerType()) {
+        CheckFunctionPointerDecl(VD->getType(), VD);
+        if (VD->getInit()) {
+          if (CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(VD->getInit())) {
+            RewriteCastExpr(CE);
+          }
+        }
+      } else if (VD->getType()->isRecordType()) {
+        RecordDecl *RD = VD->getType()->getAs<RecordType>()->getDecl();
+        if (RD->isCompleteDefinition())
+          RewriteRecordBody(RD);
+      }
+      if (VD->getInit()) {
+        GlobalVarDecl = VD;
+        CurrentBody = VD->getInit();
+        RewriteFunctionBodyOrGlobalInitializer(VD->getInit());
+        CurrentBody = nullptr;
+        if (PropParentMap) {
+          delete PropParentMap;
+          PropParentMap = nullptr;
+        }
+        SynthesizeBlockLiterals(VD->getTypeSpecStartLoc(), VD->getName());
+        GlobalVarDecl = nullptr;
+
+        // This is needed for blocks.
+        if (CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(VD->getInit())) {
+            RewriteCastExpr(CE);
+        }
+      }
+      break;
+    }
+    case Decl::TypeAlias:
+    case Decl::Typedef: {
+      if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(D)) {
+        if (isTopLevelBlockPointerType(TD->getUnderlyingType()))
+          RewriteBlockPointerDecl(TD);
+        else if (TD->getUnderlyingType()->isFunctionPointerType())
+          CheckFunctionPointerDecl(TD->getUnderlyingType(), TD);
+      }
+      break;
+    }
+    case Decl::CXXRecord:
+    case Decl::Record: {
+      RecordDecl *RD = cast<RecordDecl>(D);
+      if (RD->isCompleteDefinition()) 
+        RewriteRecordBody(RD);
+      break;
+    }
+    default:
+      break;
+  }
+  // Nothing yet.
+}
+
+void RewriteObjC::HandleTranslationUnit(ASTContext &C) {
+  if (Diags.hasErrorOccurred())
+    return;
+
+  RewriteInclude();
+
+  // Here's a great place to add any extra declarations that may be needed.
+  // Write out meta data for each @protocol(<expr>).
+  for (llvm::SmallPtrSet<ObjCProtocolDecl *,8>::iterator I = ProtocolExprDecls.begin(),
+       E = ProtocolExprDecls.end(); I != E; ++I)
+    RewriteObjCProtocolMetaData(*I, "", "", Preamble);
+
+  InsertText(SM->getLocForStartOfFile(MainFileID), Preamble, false);
+  if (ClassImplementation.size() || CategoryImplementation.size())
+    RewriteImplementations();
+
+  // Get the buffer corresponding to MainFileID.  If we haven't changed it, then
+  // we are done.
+  if (const RewriteBuffer *RewriteBuf =
+      Rewrite.getRewriteBufferFor(MainFileID)) {
+    //printf("Changed:\n");
+    *OutFile << std::string(RewriteBuf->begin(), RewriteBuf->end());
+  } else {
+    llvm::errs() << "No changes\n";
+  }
+
+  if (ClassImplementation.size() || CategoryImplementation.size() ||
+      ProtocolExprDecls.size()) {
+    // Rewrite Objective-c meta data*
+    std::string ResultStr;
+    RewriteMetaDataIntoBuffer(ResultStr);
+    // Emit metadata.
+    *OutFile << ResultStr;
+  }
+  OutFile->flush();
+}
+
+void RewriteObjCFragileABI::Initialize(ASTContext &context) {
+  InitializeCommon(context);
+  
+  // declaring objc_selector outside the parameter list removes a silly
+  // scope related warning...
+  if (IsHeader)
+    Preamble = "#pragma once\n";
+  Preamble += "struct objc_selector; struct objc_class;\n";
+  Preamble += "struct __rw_objc_super { struct objc_object *object; ";
+  Preamble += "struct objc_object *superClass; ";
+  if (LangOpts.MicrosoftExt) {
+    // Add a constructor for creating temporary objects.
+    Preamble += "__rw_objc_super(struct objc_object *o, struct objc_object *s) "
+    ": ";
+    Preamble += "object(o), superClass(s) {} ";
+  }
+  Preamble += "};\n";
+  Preamble += "#ifndef _REWRITER_typedef_Protocol\n";
+  Preamble += "typedef struct objc_object Protocol;\n";
+  Preamble += "#define _REWRITER_typedef_Protocol\n";
+  Preamble += "#endif\n";
+  if (LangOpts.MicrosoftExt) {
+    Preamble += "#define __OBJC_RW_DLLIMPORT extern \"C\" __declspec(dllimport)\n";
+    Preamble += "#define __OBJC_RW_STATICIMPORT extern \"C\"\n";
+  } else
+    Preamble += "#define __OBJC_RW_DLLIMPORT extern\n";
+  Preamble += "__OBJC_RW_DLLIMPORT struct objc_object *objc_msgSend";
+  Preamble += "(struct objc_object *, struct objc_selector *, ...);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT struct objc_object *objc_msgSendSuper";
+  Preamble += "(struct objc_super *, struct objc_selector *, ...);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT struct objc_object* objc_msgSend_stret";
+  Preamble += "(struct objc_object *, struct objc_selector *, ...);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT struct objc_object* objc_msgSendSuper_stret";
+  Preamble += "(struct objc_super *, struct objc_selector *, ...);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT double objc_msgSend_fpret";
+  Preamble += "(struct objc_object *, struct objc_selector *, ...);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT struct objc_object *objc_getClass";
+  Preamble += "(const char *);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT struct objc_class *class_getSuperclass";
+  Preamble += "(struct objc_class *);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT struct objc_object *objc_getMetaClass";
+  Preamble += "(const char *);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT void objc_exception_throw(struct objc_object *);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT void objc_exception_try_enter(void *);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT void objc_exception_try_exit(void *);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT struct objc_object *objc_exception_extract(void *);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT int objc_exception_match";
+  Preamble += "(struct objc_class *, struct objc_object *);\n";
+  // @synchronized hooks.
+  Preamble += "__OBJC_RW_DLLIMPORT int objc_sync_enter(struct objc_object *);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT int objc_sync_exit(struct objc_object *);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT Protocol *objc_getProtocol(const char *);\n";
+  Preamble += "#ifndef __FASTENUMERATIONSTATE\n";
+  Preamble += "struct __objcFastEnumerationState {\n\t";
+  Preamble += "unsigned long state;\n\t";
+  Preamble += "void **itemsPtr;\n\t";
+  Preamble += "unsigned long *mutationsPtr;\n\t";
+  Preamble += "unsigned long extra[5];\n};\n";
+  Preamble += "__OBJC_RW_DLLIMPORT void objc_enumerationMutation(struct objc_object *);\n";
+  Preamble += "#define __FASTENUMERATIONSTATE\n";
+  Preamble += "#endif\n";
+  Preamble += "#ifndef __NSCONSTANTSTRINGIMPL\n";
+  Preamble += "struct __NSConstantStringImpl {\n";
+  Preamble += "  int *isa;\n";
+  Preamble += "  int flags;\n";
+  Preamble += "  char *str;\n";
+  Preamble += "  long length;\n";
+  Preamble += "};\n";
+  Preamble += "#ifdef CF_EXPORT_CONSTANT_STRING\n";
+  Preamble += "extern \"C\" __declspec(dllexport) int __CFConstantStringClassReference[];\n";
+  Preamble += "#else\n";
+  Preamble += "__OBJC_RW_DLLIMPORT int __CFConstantStringClassReference[];\n";
+  Preamble += "#endif\n";
+  Preamble += "#define __NSCONSTANTSTRINGIMPL\n";
+  Preamble += "#endif\n";
+  // Blocks preamble.
+  Preamble += "#ifndef BLOCK_IMPL\n";
+  Preamble += "#define BLOCK_IMPL\n";
+  Preamble += "struct __block_impl {\n";
+  Preamble += "  void *isa;\n";
+  Preamble += "  int Flags;\n";
+  Preamble += "  int Reserved;\n";
+  Preamble += "  void *FuncPtr;\n";
+  Preamble += "};\n";
+  Preamble += "// Runtime copy/destroy helper functions (from Block_private.h)\n";
+  Preamble += "#ifdef __OBJC_EXPORT_BLOCKS\n";
+  Preamble += "extern \"C\" __declspec(dllexport) "
+  "void _Block_object_assign(void *, const void *, const int);\n";
+  Preamble += "extern \"C\" __declspec(dllexport) void _Block_object_dispose(const void *, const int);\n";
+  Preamble += "extern \"C\" __declspec(dllexport) void *_NSConcreteGlobalBlock[32];\n";
+  Preamble += "extern \"C\" __declspec(dllexport) void *_NSConcreteStackBlock[32];\n";
+  Preamble += "#else\n";
+  Preamble += "__OBJC_RW_DLLIMPORT void _Block_object_assign(void *, const void *, const int);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT void _Block_object_dispose(const void *, const int);\n";
+  Preamble += "__OBJC_RW_DLLIMPORT void *_NSConcreteGlobalBlock[32];\n";
+  Preamble += "__OBJC_RW_DLLIMPORT void *_NSConcreteStackBlock[32];\n";
+  Preamble += "#endif\n";
+  Preamble += "#endif\n";
+  if (LangOpts.MicrosoftExt) {
+    Preamble += "#undef __OBJC_RW_DLLIMPORT\n";
+    Preamble += "#undef __OBJC_RW_STATICIMPORT\n";
+    Preamble += "#ifndef KEEP_ATTRIBUTES\n";  // We use this for clang tests.
+    Preamble += "#define __attribute__(X)\n";
+    Preamble += "#endif\n";
+    Preamble += "#define __weak\n";
+  }
+  else {
+    Preamble += "#define __block\n";
+    Preamble += "#define __weak\n";
+  }
+  // NOTE! Windows uses LLP64 for 64bit mode. So, cast pointer to long long
+  // as this avoids warning in any 64bit/32bit compilation model.
+  Preamble += "\n#define __OFFSETOFIVAR__(TYPE, MEMBER) ((long long) &((TYPE *)0)->MEMBER)\n";
+}
+
+/// RewriteIvarOffsetComputation - This rutine synthesizes computation of
+/// ivar offset.
+void RewriteObjCFragileABI::RewriteIvarOffsetComputation(ObjCIvarDecl *ivar,
+                                                         std::string &Result) {
+  if (ivar->isBitField()) {
+    // FIXME: The hack below doesn't work for bitfields. For now, we simply
+    // place all bitfields at offset 0.
+    Result += "0";
+  } else {
+    Result += "__OFFSETOFIVAR__(struct ";
+    Result += ivar->getContainingInterface()->getNameAsString();
+    if (LangOpts.MicrosoftExt)
+      Result += "_IMPL";
+    Result += ", ";
+    Result += ivar->getNameAsString();
+    Result += ")";
+  }
+}
+
+/// RewriteObjCProtocolMetaData - Rewrite protocols meta-data.
+void RewriteObjCFragileABI::RewriteObjCProtocolMetaData(
+                            ObjCProtocolDecl *PDecl, StringRef prefix,
+                            StringRef ClassName, std::string &Result) {
+  static bool objc_protocol_methods = false;
+  
+  // Output struct protocol_methods holder of method selector and type.
+  if (!objc_protocol_methods && PDecl->hasDefinition()) {
+    /* struct protocol_methods {
+     SEL _cmd;
+     char *method_types;
+     }
+     */
+    Result += "\nstruct _protocol_methods {\n";
+    Result += "\tstruct objc_selector *_cmd;\n";
+    Result += "\tchar *method_types;\n";
+    Result += "};\n";
+    
+    objc_protocol_methods = true;
+  }
+  // Do not synthesize the protocol more than once.
+  if (ObjCSynthesizedProtocols.count(PDecl->getCanonicalDecl()))
+    return;
+  
+  if (ObjCProtocolDecl *Def = PDecl->getDefinition())
+    PDecl = Def;
+  
+  if (PDecl->instmeth_begin() != PDecl->instmeth_end()) {
+    unsigned NumMethods = std::distance(PDecl->instmeth_begin(),
+                                        PDecl->instmeth_end());
+    /* struct _objc_protocol_method_list {
+     int protocol_method_count;
+     struct protocol_methods protocols[];
+     }
+     */
+    Result += "\nstatic struct {\n";
+    Result += "\tint protocol_method_count;\n";
+    Result += "\tstruct _protocol_methods protocol_methods[";
+    Result += utostr(NumMethods);
+    Result += "];\n} _OBJC_PROTOCOL_INSTANCE_METHODS_";
+    Result += PDecl->getNameAsString();
+    Result += " __attribute__ ((used, section (\"__OBJC, __cat_inst_meth\")))= "
+    "{\n\t" + utostr(NumMethods) + "\n";
+    
+    // Output instance methods declared in this protocol.
+    for (ObjCProtocolDecl::instmeth_iterator
+         I = PDecl->instmeth_begin(), E = PDecl->instmeth_end();
+         I != E; ++I) {
+      if (I == PDecl->instmeth_begin())
+        Result += "\t  ,{{(struct objc_selector *)\"";
+      else
+        Result += "\t  ,{(struct objc_selector *)\"";
+      Result += (*I)->getSelector().getAsString();
+      std::string MethodTypeString;
+      Context->getObjCEncodingForMethodDecl((*I), MethodTypeString);
+      Result += "\", \"";
+      Result += MethodTypeString;
+      Result += "\"}\n";
+    }
+    Result += "\t }\n};\n";
+  }
+  
+  // Output class methods declared in this protocol.
+  unsigned NumMethods = std::distance(PDecl->classmeth_begin(),
+                                      PDecl->classmeth_end());
+  if (NumMethods > 0) {
+    /* struct _objc_protocol_method_list {
+     int protocol_method_count;
+     struct protocol_methods protocols[];
+     }
+     */
+    Result += "\nstatic struct {\n";
+    Result += "\tint protocol_method_count;\n";
+    Result += "\tstruct _protocol_methods protocol_methods[";
+    Result += utostr(NumMethods);
+    Result += "];\n} _OBJC_PROTOCOL_CLASS_METHODS_";
+    Result += PDecl->getNameAsString();
+    Result += " __attribute__ ((used, section (\"__OBJC, __cat_cls_meth\")))= "
+    "{\n\t";
+    Result += utostr(NumMethods);
+    Result += "\n";
+    
+    // Output instance methods declared in this protocol.
+    for (ObjCProtocolDecl::classmeth_iterator
+         I = PDecl->classmeth_begin(), E = PDecl->classmeth_end();
+         I != E; ++I) {
+      if (I == PDecl->classmeth_begin())
+        Result += "\t  ,{{(struct objc_selector *)\"";
+      else
+        Result += "\t  ,{(struct objc_selector *)\"";
+      Result += (*I)->getSelector().getAsString();
+      std::string MethodTypeString;
+      Context->getObjCEncodingForMethodDecl((*I), MethodTypeString);
+      Result += "\", \"";
+      Result += MethodTypeString;
+      Result += "\"}\n";
+    }
+    Result += "\t }\n};\n";
+  }
+  
+  // Output:
+  /* struct _objc_protocol {
+   // Objective-C 1.0 extensions
+   struct _objc_protocol_extension *isa;
+   char *protocol_name;
+   struct _objc_protocol **protocol_list;
+   struct _objc_protocol_method_list *instance_methods;
+   struct _objc_protocol_method_list *class_methods;
+   };
+   */
+  static bool objc_protocol = false;
+  if (!objc_protocol) {
+    Result += "\nstruct _objc_protocol {\n";
+    Result += "\tstruct _objc_protocol_extension *isa;\n";
+    Result += "\tchar *protocol_name;\n";
+    Result += "\tstruct _objc_protocol **protocol_list;\n";
+    Result += "\tstruct _objc_protocol_method_list *instance_methods;\n";
+    Result += "\tstruct _objc_protocol_method_list *class_methods;\n";
+    Result += "};\n";
+    
+    objc_protocol = true;
+  }
+  
+  Result += "\nstatic struct _objc_protocol _OBJC_PROTOCOL_";
+  Result += PDecl->getNameAsString();
+  Result += " __attribute__ ((used, section (\"__OBJC, __protocol\")))= "
+  "{\n\t0, \"";
+  Result += PDecl->getNameAsString();
+  Result += "\", 0, ";
+  if (PDecl->instmeth_begin() != PDecl->instmeth_end()) {
+    Result += "(struct _objc_protocol_method_list *)&_OBJC_PROTOCOL_INSTANCE_METHODS_";
+    Result += PDecl->getNameAsString();
+    Result += ", ";
+  }
+  else
+    Result += "0, ";
+  if (PDecl->classmeth_begin() != PDecl->classmeth_end()) {
+    Result += "(struct _objc_protocol_method_list *)&_OBJC_PROTOCOL_CLASS_METHODS_";
+    Result += PDecl->getNameAsString();
+    Result += "\n";
+  }
+  else
+    Result += "0\n";
+  Result += "};\n";
+  
+  // Mark this protocol as having been generated.
+  if (!ObjCSynthesizedProtocols.insert(PDecl->getCanonicalDecl()))
+    llvm_unreachable("protocol already synthesized");
+  
+}
+
+void RewriteObjCFragileABI::RewriteObjCProtocolListMetaData(
+                                const ObjCList<ObjCProtocolDecl> &Protocols,
+                                StringRef prefix, StringRef ClassName,
+                                std::string &Result) {
+  if (Protocols.empty()) return;
+  
+  for (unsigned i = 0; i != Protocols.size(); i++)
+    RewriteObjCProtocolMetaData(Protocols[i], prefix, ClassName, Result);
+  
+  // Output the top lovel protocol meta-data for the class.
+  /* struct _objc_protocol_list {
+   struct _objc_protocol_list *next;
+   int    protocol_count;
+   struct _objc_protocol *class_protocols[];
+   }
+   */
+  Result += "\nstatic struct {\n";
+  Result += "\tstruct _objc_protocol_list *next;\n";
+  Result += "\tint    protocol_count;\n";
+  Result += "\tstruct _objc_protocol *class_protocols[";
+  Result += utostr(Protocols.size());
+  Result += "];\n} _OBJC_";
+  Result += prefix;
+  Result += "_PROTOCOLS_";
+  Result += ClassName;
+  Result += " __attribute__ ((used, section (\"__OBJC, __cat_cls_meth\")))= "
+  "{\n\t0, ";
+  Result += utostr(Protocols.size());
+  Result += "\n";
+  
+  Result += "\t,{&_OBJC_PROTOCOL_";
+  Result += Protocols[0]->getNameAsString();
+  Result += " \n";
+  
+  for (unsigned i = 1; i != Protocols.size(); i++) {
+    Result += "\t ,&_OBJC_PROTOCOL_";
+    Result += Protocols[i]->getNameAsString();
+    Result += "\n";
+  }
+  Result += "\t }\n};\n";
+}
+
+void RewriteObjCFragileABI::RewriteObjCClassMetaData(ObjCImplementationDecl *IDecl,
+                                           std::string &Result) {
+  ObjCInterfaceDecl *CDecl = IDecl->getClassInterface();
+  
+  // Explicitly declared @interface's are already synthesized.
+  if (CDecl->isImplicitInterfaceDecl()) {
+    // FIXME: Implementation of a class with no @interface (legacy) does not
+    // produce correct synthesis as yet.
+    RewriteObjCInternalStruct(CDecl, Result);
+  }
+  
+  // Build _objc_ivar_list metadata for classes ivars if needed
+  unsigned NumIvars = !IDecl->ivar_empty()
+  ? IDecl->ivar_size()
+  : (CDecl ? CDecl->ivar_size() : 0);
+  if (NumIvars > 0) {
+    static bool objc_ivar = false;
+    if (!objc_ivar) {
+      /* struct _objc_ivar {
+       char *ivar_name;
+       char *ivar_type;
+       int ivar_offset;
+       };
+       */
+      Result += "\nstruct _objc_ivar {\n";
+      Result += "\tchar *ivar_name;\n";
+      Result += "\tchar *ivar_type;\n";
+      Result += "\tint ivar_offset;\n";
+      Result += "};\n";
+      
+      objc_ivar = true;
+    }
+    
+    /* struct {
+     int ivar_count;
+     struct _objc_ivar ivar_list[nIvars];
+     };
+     */
+    Result += "\nstatic struct {\n";
+    Result += "\tint ivar_count;\n";
+    Result += "\tstruct _objc_ivar ivar_list[";
+    Result += utostr(NumIvars);
+    Result += "];\n} _OBJC_INSTANCE_VARIABLES_";
+    Result += IDecl->getNameAsString();
+    Result += " __attribute__ ((used, section (\"__OBJC, __instance_vars\")))= "
+    "{\n\t";
+    Result += utostr(NumIvars);
+    Result += "\n";
+    
+    ObjCInterfaceDecl::ivar_iterator IVI, IVE;
+    SmallVector<ObjCIvarDecl *, 8> IVars;
+    if (!IDecl->ivar_empty()) {
+      for (auto *IV : IDecl->ivars())
+        IVars.push_back(IV);
+      IVI = IDecl->ivar_begin();
+      IVE = IDecl->ivar_end();
+    } else {
+      IVI = CDecl->ivar_begin();
+      IVE = CDecl->ivar_end();
+    }
+    Result += "\t,{{\"";
+    Result += IVI->getNameAsString();
+    Result += "\", \"";
+    std::string TmpString, StrEncoding;
+    Context->getObjCEncodingForType(IVI->getType(), TmpString, *IVI);
+    QuoteDoublequotes(TmpString, StrEncoding);
+    Result += StrEncoding;
+    Result += "\", ";
+    RewriteIvarOffsetComputation(*IVI, Result);
+    Result += "}\n";
+    for (++IVI; IVI != IVE; ++IVI) {
+      Result += "\t  ,{\"";
+      Result += IVI->getNameAsString();
+      Result += "\", \"";
+      std::string TmpString, StrEncoding;
+      Context->getObjCEncodingForType(IVI->getType(), TmpString, *IVI);
+      QuoteDoublequotes(TmpString, StrEncoding);
+      Result += StrEncoding;
+      Result += "\", ";
+      RewriteIvarOffsetComputation(*IVI, Result);
+      Result += "}\n";
+    }
+    
+    Result += "\t }\n};\n";
+  }
+  
+  // Build _objc_method_list for class's instance methods if needed
+  SmallVector<ObjCMethodDecl *, 32> InstanceMethods(IDecl->instance_methods());
+  
+  // If any of our property implementations have associated getters or
+  // setters, produce metadata for them as well.
+  for (const auto *Prop : IDecl->property_impls()) {
+    if (Prop->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic)
+      continue;
+    if (!Prop->getPropertyIvarDecl())
+      continue;
+    ObjCPropertyDecl *PD = Prop->getPropertyDecl();
+    if (!PD)
+      continue;
+    if (ObjCMethodDecl *Getter = PD->getGetterMethodDecl())
+      if (!Getter->isDefined())
+        InstanceMethods.push_back(Getter);
+    if (PD->isReadOnly())
+      continue;
+    if (ObjCMethodDecl *Setter = PD->getSetterMethodDecl())
+      if (!Setter->isDefined())
+        InstanceMethods.push_back(Setter);
+  }
+  RewriteObjCMethodsMetaData(InstanceMethods.begin(), InstanceMethods.end(),
+                             true, "", IDecl->getName(), Result);
+  
+  // Build _objc_method_list for class's class methods if needed
+  RewriteObjCMethodsMetaData(IDecl->classmeth_begin(), IDecl->classmeth_end(),
+                             false, "", IDecl->getName(), Result);
+  
+  // Protocols referenced in class declaration?
+  RewriteObjCProtocolListMetaData(CDecl->getReferencedProtocols(),
+                                  "CLASS", CDecl->getName(), Result);
+  
+  // Declaration of class/meta-class metadata
+  /* struct _objc_class {
+   struct _objc_class *isa; // or const char *root_class_name when metadata
+   const char *super_class_name;
+   char *name;
+   long version;
+   long info;
+   long instance_size;
+   struct _objc_ivar_list *ivars;
+   struct _objc_method_list *methods;
+   struct objc_cache *cache;
+   struct objc_protocol_list *protocols;
+   const char *ivar_layout;
+   struct _objc_class_ext  *ext;
+   };
+   */
+  static bool objc_class = false;
+  if (!objc_class) {
+    Result += "\nstruct _objc_class {\n";
+    Result += "\tstruct _objc_class *isa;\n";
+    Result += "\tconst char *super_class_name;\n";
+    Result += "\tchar *name;\n";
+    Result += "\tlong version;\n";
+    Result += "\tlong info;\n";
+    Result += "\tlong instance_size;\n";
+    Result += "\tstruct _objc_ivar_list *ivars;\n";
+    Result += "\tstruct _objc_method_list *methods;\n";
+    Result += "\tstruct objc_cache *cache;\n";
+    Result += "\tstruct _objc_protocol_list *protocols;\n";
+    Result += "\tconst char *ivar_layout;\n";
+    Result += "\tstruct _objc_class_ext  *ext;\n";
+    Result += "};\n";
+    objc_class = true;
+  }
+  
+  // Meta-class metadata generation.
+  ObjCInterfaceDecl *RootClass = nullptr;
+  ObjCInterfaceDecl *SuperClass = CDecl->getSuperClass();
+  while (SuperClass) {
+    RootClass = SuperClass;
+    SuperClass = SuperClass->getSuperClass();
+  }
+  SuperClass = CDecl->getSuperClass();
+  
+  Result += "\nstatic struct _objc_class _OBJC_METACLASS_";
+  Result += CDecl->getNameAsString();
+  Result += " __attribute__ ((used, section (\"__OBJC, __meta_class\")))= "
+  "{\n\t(struct _objc_class *)\"";
+  Result += (RootClass ? RootClass->getNameAsString() : CDecl->getNameAsString());
+  Result += "\"";
+  
+  if (SuperClass) {
+    Result += ", \"";
+    Result += SuperClass->getNameAsString();
+    Result += "\", \"";
+    Result += CDecl->getNameAsString();
+    Result += "\"";
+  }
+  else {
+    Result += ", 0, \"";
+    Result += CDecl->getNameAsString();
+    Result += "\"";
+  }
+  // Set 'ivars' field for root class to 0. ObjC1 runtime does not use it.
+  // 'info' field is initialized to CLS_META(2) for metaclass
+  Result += ", 0,2, sizeof(struct _objc_class), 0";
+  if (IDecl->classmeth_begin() != IDecl->classmeth_end()) {
+    Result += "\n\t, (struct _objc_method_list *)&_OBJC_CLASS_METHODS_";
+    Result += IDecl->getNameAsString();
+    Result += "\n";
+  }
+  else
+    Result += ", 0\n";
+  if (CDecl->protocol_begin() != CDecl->protocol_end()) {
+    Result += "\t,0, (struct _objc_protocol_list *)&_OBJC_CLASS_PROTOCOLS_";
+    Result += CDecl->getNameAsString();
+    Result += ",0,0\n";
+  }
+  else
+    Result += "\t,0,0,0,0\n";
+  Result += "};\n";
+  
+  // class metadata generation.
+  Result += "\nstatic struct _objc_class _OBJC_CLASS_";
+  Result += CDecl->getNameAsString();
+  Result += " __attribute__ ((used, section (\"__OBJC, __class\")))= "
+  "{\n\t&_OBJC_METACLASS_";
+  Result += CDecl->getNameAsString();
+  if (SuperClass) {
+    Result += ", \"";
+    Result += SuperClass->getNameAsString();
+    Result += "\", \"";
+    Result += CDecl->getNameAsString();
+    Result += "\"";
+  }
+  else {
+    Result += ", 0, \"";
+    Result += CDecl->getNameAsString();
+    Result += "\"";
+  }
+  // 'info' field is initialized to CLS_CLASS(1) for class
+  Result += ", 0,1";
+  if (!ObjCSynthesizedStructs.count(CDecl))
+    Result += ",0";
+  else {
+    // class has size. Must synthesize its size.
+    Result += ",sizeof(struct ";
+    Result += CDecl->getNameAsString();
+    if (LangOpts.MicrosoftExt)
+      Result += "_IMPL";
+    Result += ")";
+  }
+  if (NumIvars > 0) {
+    Result += ", (struct _objc_ivar_list *)&_OBJC_INSTANCE_VARIABLES_";
+    Result += CDecl->getNameAsString();
+    Result += "\n\t";
+  }
+  else
+    Result += ",0";
+  if (IDecl->instmeth_begin() != IDecl->instmeth_end()) {
+    Result += ", (struct _objc_method_list *)&_OBJC_INSTANCE_METHODS_";
+    Result += CDecl->getNameAsString();
+    Result += ", 0\n\t";
+  }
+  else
+    Result += ",0,0";
+  if (CDecl->protocol_begin() != CDecl->protocol_end()) {
+    Result += ", (struct _objc_protocol_list*)&_OBJC_CLASS_PROTOCOLS_";
+    Result += CDecl->getNameAsString();
+    Result += ", 0,0\n";
+  }
+  else
+    Result += ",0,0,0\n";
+  Result += "};\n";
+}
+
+void RewriteObjCFragileABI::RewriteMetaDataIntoBuffer(std::string &Result) {
+  int ClsDefCount = ClassImplementation.size();
+  int CatDefCount = CategoryImplementation.size();
+  
+  // For each implemented class, write out all its meta data.
+  for (int i = 0; i < ClsDefCount; i++)
+    RewriteObjCClassMetaData(ClassImplementation[i], Result);
+  
+  // For each implemented category, write out all its meta data.
+  for (int i = 0; i < CatDefCount; i++)
+    RewriteObjCCategoryImplDecl(CategoryImplementation[i], Result);
+  
+  // Write objc_symtab metadata
+  /*
+   struct _objc_symtab
+   {
+   long sel_ref_cnt;
+   SEL *refs;
+   short cls_def_cnt;
+   short cat_def_cnt;
+   void *defs[cls_def_cnt + cat_def_cnt];
+   };
+   */
+  
+  Result += "\nstruct _objc_symtab {\n";
+  Result += "\tlong sel_ref_cnt;\n";
+  Result += "\tSEL *refs;\n";
+  Result += "\tshort cls_def_cnt;\n";
+  Result += "\tshort cat_def_cnt;\n";
+  Result += "\tvoid *defs[" + utostr(ClsDefCount + CatDefCount)+ "];\n";
+  Result += "};\n\n";
+  
+  Result += "static struct _objc_symtab "
+  "_OBJC_SYMBOLS __attribute__((used, section (\"__OBJC, __symbols\")))= {\n";
+  Result += "\t0, 0, " + utostr(ClsDefCount)
+  + ", " + utostr(CatDefCount) + "\n";
+  for (int i = 0; i < ClsDefCount; i++) {
+    Result += "\t,&_OBJC_CLASS_";
+    Result += ClassImplementation[i]->getNameAsString();
+    Result += "\n";
+  }
+  
+  for (int i = 0; i < CatDefCount; i++) {
+    Result += "\t,&_OBJC_CATEGORY_";
+    Result += CategoryImplementation[i]->getClassInterface()->getNameAsString();
+    Result += "_";
+    Result += CategoryImplementation[i]->getNameAsString();
+    Result += "\n";
+  }
+  
+  Result += "};\n\n";
+  
+  // Write objc_module metadata
+  
+  /*
+   struct _objc_module {
+   long version;
+   long size;
+   const char *name;
+   struct _objc_symtab *symtab;
+   }
+   */
+  
+  Result += "\nstruct _objc_module {\n";
+  Result += "\tlong version;\n";
+  Result += "\tlong size;\n";
+  Result += "\tconst char *name;\n";
+  Result += "\tstruct _objc_symtab *symtab;\n";
+  Result += "};\n\n";
+  Result += "static struct _objc_module "
+  "_OBJC_MODULES __attribute__ ((used, section (\"__OBJC, __module_info\")))= {\n";
+  Result += "\t" + utostr(OBJC_ABI_VERSION) +
+  ", sizeof(struct _objc_module), \"\", &_OBJC_SYMBOLS\n";
+  Result += "};\n\n";
+  
+  if (LangOpts.MicrosoftExt) {
+    if (ProtocolExprDecls.size()) {
+      Result += "#pragma section(\".objc_protocol$B\",long,read,write)\n";
+      Result += "#pragma data_seg(push, \".objc_protocol$B\")\n";
+      for (llvm::SmallPtrSet<ObjCProtocolDecl *,8>::iterator I = ProtocolExprDecls.begin(),
+           E = ProtocolExprDecls.end(); I != E; ++I) {
+        Result += "static struct _objc_protocol *_POINTER_OBJC_PROTOCOL_";
+        Result += (*I)->getNameAsString();
+        Result += " = &_OBJC_PROTOCOL_";
+        Result += (*I)->getNameAsString();
+        Result += ";\n";
+      }
+      Result += "#pragma data_seg(pop)\n\n";
+    }
+    Result += "#pragma section(\".objc_module_info$B\",long,read,write)\n";
+    Result += "#pragma data_seg(push, \".objc_module_info$B\")\n";
+    Result += "static struct _objc_module *_POINTER_OBJC_MODULES = ";
+    Result += "&_OBJC_MODULES;\n";
+    Result += "#pragma data_seg(pop)\n\n";
+  }
+}
+
+/// RewriteObjCCategoryImplDecl - Rewrite metadata for each category
+/// implementation.
+void RewriteObjCFragileABI::RewriteObjCCategoryImplDecl(ObjCCategoryImplDecl *IDecl,
+                                              std::string &Result) {
+  ObjCInterfaceDecl *ClassDecl = IDecl->getClassInterface();
+  // Find category declaration for this implementation.
+  ObjCCategoryDecl *CDecl
+    = ClassDecl->FindCategoryDeclaration(IDecl->getIdentifier());
+  
+  std::string FullCategoryName = ClassDecl->getNameAsString();
+  FullCategoryName += '_';
+  FullCategoryName += IDecl->getNameAsString();
+  
+  // Build _objc_method_list for class's instance methods if needed
+  SmallVector<ObjCMethodDecl *, 32> InstanceMethods(IDecl->instance_methods());
+  
+  // If any of our property implementations have associated getters or
+  // setters, produce metadata for them as well.
+  for (const auto *Prop : IDecl->property_impls()) {
+    if (Prop->getPropertyImplementation() == ObjCPropertyImplDecl::Dynamic)
+      continue;
+    if (!Prop->getPropertyIvarDecl())
+      continue;
+    ObjCPropertyDecl *PD = Prop->getPropertyDecl();
+    if (!PD)
+      continue;
+    if (ObjCMethodDecl *Getter = PD->getGetterMethodDecl())
+      InstanceMethods.push_back(Getter);
+    if (PD->isReadOnly())
+      continue;
+    if (ObjCMethodDecl *Setter = PD->getSetterMethodDecl())
+      InstanceMethods.push_back(Setter);
+  }
+  RewriteObjCMethodsMetaData(InstanceMethods.begin(), InstanceMethods.end(),
+                             true, "CATEGORY_", FullCategoryName.c_str(),
+                             Result);
+  
+  // Build _objc_method_list for class's class methods if needed
+  RewriteObjCMethodsMetaData(IDecl->classmeth_begin(), IDecl->classmeth_end(),
+                             false, "CATEGORY_", FullCategoryName.c_str(),
+                             Result);
+  
+  // Protocols referenced in class declaration?
+  // Null CDecl is case of a category implementation with no category interface
+  if (CDecl)
+    RewriteObjCProtocolListMetaData(CDecl->getReferencedProtocols(), "CATEGORY",
+                                    FullCategoryName, Result);
+  /* struct _objc_category {
+   char *category_name;
+   char *class_name;
+   struct _objc_method_list *instance_methods;
+   struct _objc_method_list *class_methods;
+   struct _objc_protocol_list *protocols;
+   // Objective-C 1.0 extensions
+   uint32_t size;     // sizeof (struct _objc_category)
+   struct _objc_property_list *instance_properties;  // category's own
+   // @property decl.
+   };
+   */
+  
+  static bool objc_category = false;
+  if (!objc_category) {
+    Result += "\nstruct _objc_category {\n";
+    Result += "\tchar *category_name;\n";
+    Result += "\tchar *class_name;\n";
+    Result += "\tstruct _objc_method_list *instance_methods;\n";
+    Result += "\tstruct _objc_method_list *class_methods;\n";
+    Result += "\tstruct _objc_protocol_list *protocols;\n";
+    Result += "\tunsigned int size;\n";
+    Result += "\tstruct _objc_property_list *instance_properties;\n";
+    Result += "};\n";
+    objc_category = true;
+  }
+  Result += "\nstatic struct _objc_category _OBJC_CATEGORY_";
+  Result += FullCategoryName;
+  Result += " __attribute__ ((used, section (\"__OBJC, __category\")))= {\n\t\"";
+  Result += IDecl->getNameAsString();
+  Result += "\"\n\t, \"";
+  Result += ClassDecl->getNameAsString();
+  Result += "\"\n";
+  
+  if (IDecl->instmeth_begin() != IDecl->instmeth_end()) {
+    Result += "\t, (struct _objc_method_list *)"
+    "&_OBJC_CATEGORY_INSTANCE_METHODS_";
+    Result += FullCategoryName;
+    Result += "\n";
+  }
+  else
+    Result += "\t, 0\n";
+  if (IDecl->classmeth_begin() != IDecl->classmeth_end()) {
+    Result += "\t, (struct _objc_method_list *)"
+    "&_OBJC_CATEGORY_CLASS_METHODS_";
+    Result += FullCategoryName;
+    Result += "\n";
+  }
+  else
+    Result += "\t, 0\n";
+  
+  if (CDecl && CDecl->protocol_begin() != CDecl->protocol_end()) {
+    Result += "\t, (struct _objc_protocol_list *)&_OBJC_CATEGORY_PROTOCOLS_";
+    Result += FullCategoryName;
+    Result += "\n";
+  }
+  else
+    Result += "\t, 0\n";
+  Result += "\t, sizeof(struct _objc_category), 0\n};\n";
+}
+
+// RewriteObjCMethodsMetaData - Rewrite methods metadata for instance or
+/// class methods.
+template<typename MethodIterator>
+void RewriteObjCFragileABI::RewriteObjCMethodsMetaData(MethodIterator MethodBegin,
+                                             MethodIterator MethodEnd,
+                                             bool IsInstanceMethod,
+                                             StringRef prefix,
+                                             StringRef ClassName,
+                                             std::string &Result) {
+  if (MethodBegin == MethodEnd) return;
+  
+  if (!objc_impl_method) {
+    /* struct _objc_method {
+     SEL _cmd;
+     char *method_types;
+     void *_imp;
+     }
+     */
+    Result += "\nstruct _objc_method {\n";
+    Result += "\tSEL _cmd;\n";
+    Result += "\tchar *method_types;\n";
+    Result += "\tvoid *_imp;\n";
+    Result += "};\n";
+    
+    objc_impl_method = true;
+  }
+  
+  // Build _objc_method_list for class's methods if needed
+  
+  /* struct  {
+   struct _objc_method_list *next_method;
+   int method_count;
+   struct _objc_method method_list[];
+   }
+   */
+  unsigned NumMethods = std::distance(MethodBegin, MethodEnd);
+  Result += "\nstatic struct {\n";
+  Result += "\tstruct _objc_method_list *next_method;\n";
+  Result += "\tint method_count;\n";
+  Result += "\tstruct _objc_method method_list[";
+  Result += utostr(NumMethods);
+  Result += "];\n} _OBJC_";
+  Result += prefix;
+  Result += IsInstanceMethod ? "INSTANCE" : "CLASS";
+  Result += "_METHODS_";
+  Result += ClassName;
+  Result += " __attribute__ ((used, section (\"__OBJC, __";
+  Result += IsInstanceMethod ? "inst" : "cls";
+  Result += "_meth\")))= ";
+  Result += "{\n\t0, " + utostr(NumMethods) + "\n";
+  
+  Result += "\t,{{(SEL)\"";
+  Result += (*MethodBegin)->getSelector().getAsString().c_str();
+  std::string MethodTypeString;
+  Context->getObjCEncodingForMethodDecl(*MethodBegin, MethodTypeString);
+  Result += "\", \"";
+  Result += MethodTypeString;
+  Result += "\", (void *)";
+  Result += MethodInternalNames[*MethodBegin];
+  Result += "}\n";
+  for (++MethodBegin; MethodBegin != MethodEnd; ++MethodBegin) {
+    Result += "\t  ,{(SEL)\"";
+    Result += (*MethodBegin)->getSelector().getAsString().c_str();
+    std::string MethodTypeString;
+    Context->getObjCEncodingForMethodDecl(*MethodBegin, MethodTypeString);
+    Result += "\", \"";
+    Result += MethodTypeString;
+    Result += "\", (void *)";
+    Result += MethodInternalNames[*MethodBegin];
+    Result += "}\n";
+  }
+  Result += "\t }\n};\n";
+}
+
+Stmt *RewriteObjCFragileABI::RewriteObjCIvarRefExpr(ObjCIvarRefExpr *IV) {
+  SourceRange OldRange = IV->getSourceRange();
+  Expr *BaseExpr = IV->getBase();
+  
+  // Rewrite the base, but without actually doing replaces.
+  {
+    DisableReplaceStmtScope S(*this);
+    BaseExpr = cast<Expr>(RewriteFunctionBodyOrGlobalInitializer(BaseExpr));
+    IV->setBase(BaseExpr);
+  }
+  
+  ObjCIvarDecl *D = IV->getDecl();
+  
+  Expr *Replacement = IV;
+  if (CurMethodDef) {
+    if (BaseExpr->getType()->isObjCObjectPointerType()) {
+      const ObjCInterfaceType *iFaceDecl =
+      dyn_cast<ObjCInterfaceType>(BaseExpr->getType()->getPointeeType());
+      assert(iFaceDecl && "RewriteObjCIvarRefExpr - iFaceDecl is null");
+      // lookup which class implements the instance variable.
+      ObjCInterfaceDecl *clsDeclared = nullptr;
+      iFaceDecl->getDecl()->lookupInstanceVariable(D->getIdentifier(),
+                                                   clsDeclared);
+      assert(clsDeclared && "RewriteObjCIvarRefExpr(): Can't find class");
+      
+      // Synthesize an explicit cast to gain access to the ivar.
+      std::string RecName = clsDeclared->getIdentifier()->getName();
+      RecName += "_IMPL";
+      IdentifierInfo *II = &Context->Idents.get(RecName);
+      RecordDecl *RD = RecordDecl::Create(*Context, TTK_Struct, TUDecl,
+                                          SourceLocation(), SourceLocation(),
+                                          II);
+      assert(RD && "RewriteObjCIvarRefExpr(): Can't find RecordDecl");
+      QualType castT = Context->getPointerType(Context->getTagDeclType(RD));
+      CastExpr *castExpr = NoTypeInfoCStyleCastExpr(Context, castT,
+                                                    CK_BitCast,
+                                                    IV->getBase());
+      // Don't forget the parens to enforce the proper binding.
+      ParenExpr *PE = new (Context) ParenExpr(OldRange.getBegin(),
+                                              OldRange.getEnd(),
+                                              castExpr);
+      if (IV->isFreeIvar() &&
+          declaresSameEntity(CurMethodDef->getClassInterface(), iFaceDecl->getDecl())) {
+        MemberExpr *ME = new (Context) MemberExpr(PE, true, D,
+                                                  IV->getLocation(),
+                                                  D->getType(),
+                                                  VK_LValue, OK_Ordinary);
+        Replacement = ME;
+      } else {
+        IV->setBase(PE);
+      }
+    }
+  } else { // we are outside a method.
+    assert(!IV->isFreeIvar() && "Cannot have a free standing ivar outside a method");
+    
+    // Explicit ivar refs need to have a cast inserted.
+    // FIXME: consider sharing some of this code with the code above.
+    if (BaseExpr->getType()->isObjCObjectPointerType()) {
+      const ObjCInterfaceType *iFaceDecl =
+      dyn_cast<ObjCInterfaceType>(BaseExpr->getType()->getPointeeType());
+      // lookup which class implements the instance variable.
+      ObjCInterfaceDecl *clsDeclared = nullptr;
+      iFaceDecl->getDecl()->lookupInstanceVariable(D->getIdentifier(),
+                                                   clsDeclared);
+      assert(clsDeclared && "RewriteObjCIvarRefExpr(): Can't find class");
+      
+      // Synthesize an explicit cast to gain access to the ivar.
+      std::string RecName = clsDeclared->getIdentifier()->getName();
+      RecName += "_IMPL";
+      IdentifierInfo *II = &Context->Idents.get(RecName);
+      RecordDecl *RD = RecordDecl::Create(*Context, TTK_Struct, TUDecl,
+                                          SourceLocation(), SourceLocation(),
+                                          II);
+      assert(RD && "RewriteObjCIvarRefExpr(): Can't find RecordDecl");
+      QualType castT = Context->getPointerType(Context->getTagDeclType(RD));
+      CastExpr *castExpr = NoTypeInfoCStyleCastExpr(Context, castT,
+                                                    CK_BitCast,
+                                                    IV->getBase());
+      // Don't forget the parens to enforce the proper binding.
+      ParenExpr *PE = new (Context) ParenExpr(IV->getBase()->getLocStart(),
+                                              IV->getBase()->getLocEnd(), castExpr);
+      // Cannot delete IV->getBase(), since PE points to it.
+      // Replace the old base with the cast. This is important when doing
+      // embedded rewrites. For example, [newInv->_container addObject:0].
+      IV->setBase(PE);
+    }
+  }
+  
+  ReplaceStmtWithRange(IV, Replacement, OldRange);
+  return Replacement;  
+}
+
+#endif
diff --git a/lib/Frontend/Rewrite/RewriteTest.cpp b/lib/Frontend/Rewrite/RewriteTest.cpp
new file mode 100644
index 000000000000..722c5e80b443
--- /dev/null
+++ b/lib/Frontend/Rewrite/RewriteTest.cpp
@@ -0,0 +1,39 @@
+//===--- RewriteTest.cpp - Rewriter playground ----------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This is a testbed.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Rewrite/Frontend/Rewriters.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Rewrite/Core/TokenRewriter.h"
+#include "llvm/Support/raw_ostream.h"
+
+void clang::DoRewriteTest(Preprocessor &PP, raw_ostream* OS) {
+  SourceManager &SM = PP.getSourceManager();
+  const LangOptions &LangOpts = PP.getLangOpts();
+
+  TokenRewriter Rewriter(SM.getMainFileID(), SM, LangOpts);
+
+  // Throw <i> </i> tags around comments.
+  for (TokenRewriter::token_iterator I = Rewriter.token_begin(),
+       E = Rewriter.token_end(); I != E; ++I) {
+    if (I->isNot(tok::comment)) continue;
+
+    Rewriter.AddTokenBefore(I, "<i>");
+    Rewriter.AddTokenAfter(I, "</i>");
+  }
+
+
+  // Print out the output.
+  for (TokenRewriter::token_iterator I = Rewriter.token_begin(),
+       E = Rewriter.token_end(); I != E; ++I)
+    *OS << PP.getSpelling(*I);
+}
diff --git a/lib/Frontend/SerializedDiagnosticPrinter.cpp b/lib/Frontend/SerializedDiagnosticPrinter.cpp
index 6514321f228d..29c58a8ac34e 100644
--- a/lib/Frontend/SerializedDiagnosticPrinter.cpp
+++ b/lib/Frontend/SerializedDiagnosticPrinter.cpp
@@ -59,32 +59,32 @@ public:
   virtual ~SDiagsRenderer() {}
   
 protected:
-  virtual void emitDiagnosticMessage(SourceLocation Loc,
-                                     PresumedLoc PLoc,
-                                     DiagnosticsEngine::Level Level,
-                                     StringRef Message,
-                                     ArrayRef<CharSourceRange> Ranges,
-                                     const SourceManager *SM,
-                                     DiagOrStoredDiag D);
-  
-  virtual void emitDiagnosticLoc(SourceLocation Loc, PresumedLoc PLoc,
-                                 DiagnosticsEngine::Level Level,
-                                 ArrayRef<CharSourceRange> Ranges,
-                                 const SourceManager &SM) {}
-
-  virtual void emitNote(SourceLocation Loc, StringRef Message,
-                        const SourceManager *SM);
-
-  virtual void emitCodeContext(SourceLocation Loc,
-                               DiagnosticsEngine::Level Level,
-                               SmallVectorImpl<CharSourceRange>& Ranges,
-                               ArrayRef<FixItHint> Hints,
-                               const SourceManager &SM);
-
-  virtual void beginDiagnostic(DiagOrStoredDiag D,
-                               DiagnosticsEngine::Level Level);
-  virtual void endDiagnostic(DiagOrStoredDiag D,
-                             DiagnosticsEngine::Level Level);
+  void emitDiagnosticMessage(SourceLocation Loc,
+                             PresumedLoc PLoc,
+                             DiagnosticsEngine::Level Level,
+                             StringRef Message,
+                             ArrayRef<CharSourceRange> Ranges,
+                             const SourceManager *SM,
+                             DiagOrStoredDiag D) override;
+
+  void emitDiagnosticLoc(SourceLocation Loc, PresumedLoc PLoc,
+                         DiagnosticsEngine::Level Level,
+                         ArrayRef<CharSourceRange> Ranges,
+                         const SourceManager &SM) override {}
+
+  void emitNote(SourceLocation Loc, StringRef Message,
+                const SourceManager *SM) override;
+
+  void emitCodeContext(SourceLocation Loc,
+                       DiagnosticsEngine::Level Level,
+                       SmallVectorImpl<CharSourceRange>& Ranges,
+                       ArrayRef<FixItHint> Hints,
+                       const SourceManager &SM) override;
+
+  void beginDiagnostic(DiagOrStoredDiag D,
+                       DiagnosticsEngine::Level Level) override;
+  void endDiagnostic(DiagOrStoredDiag D,
+                     DiagnosticsEngine::Level Level) override;
 };
   
 class SDiagsWriter : public DiagnosticConsumer {
@@ -93,26 +93,26 @@ class SDiagsWriter : public DiagnosticConsumer {
   struct SharedState;
 
   explicit SDiagsWriter(IntrusiveRefCntPtr<SharedState> State)
-    : LangOpts(0), OriginalInstance(false), State(State) { }
+    : LangOpts(nullptr), OriginalInstance(false), State(State) {}
 
 public:
   SDiagsWriter(raw_ostream *os, DiagnosticOptions *diags)
-    : LangOpts(0), OriginalInstance(true), State(new SharedState(os, diags))
+    : LangOpts(nullptr), OriginalInstance(true),
+      State(new SharedState(os, diags))
   {
     EmitPreamble();
   }
 
   ~SDiagsWriter() {}
-  
+
   void HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
-                        const Diagnostic &Info);
-  
-  void BeginSourceFile(const LangOptions &LO,
-                       const Preprocessor *PP) {
+                        const Diagnostic &Info) override;
+
+  void BeginSourceFile(const LangOptions &LO, const Preprocessor *PP) override {
     LangOpts = &LO;
   }
 
-  virtual void finish();
+  void finish() override;
 
 private:
   /// \brief Emit the preamble for the serialized diagnostics.
@@ -174,7 +174,7 @@ private:
                                   const SourceManager &SM);
 
   /// \brief The version of the diagnostics file.
-  enum { Version = 1 };
+  enum { Version = 2 };
 
   /// \brief Language options, which can differ from one clone of this client
   /// to another.
@@ -200,7 +200,7 @@ private:
     llvm::BitstreamWriter Stream;
 
     /// \brief The name of the diagnostics file.
-    OwningPtr<raw_ostream> OS;
+    std::unique_ptr<raw_ostream> OS;
 
     /// \brief The set of constructed record abbreviations.
     AbbreviationMap Abbrevs;
@@ -255,7 +255,7 @@ static void EmitBlockID(unsigned ID, const char *Name,
   Stream.EmitRecord(llvm::bitc::BLOCKINFO_CODE_SETBID, Record);
   
   // Emit the block name if present.
-  if (Name == 0 || Name[0] == 0)
+  if (!Name || Name[0] == 0)
     return;
 
   Record.clear();
@@ -546,7 +546,7 @@ void SDiagsWriter::HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
       EnterDiagBlock();
 
     EmitDiagnosticMessage(SourceLocation(), PresumedLoc(), DiagLevel,
-                          State->diagBuf, 0, &Info);
+                          State->diagBuf, nullptr, &Info);
 
     if (DiagLevel == DiagnosticsEngine::Note)
       ExitDiagBlock();
@@ -560,12 +560,26 @@ void SDiagsWriter::HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
   Renderer.emitDiagnostic(Info.getLocation(), DiagLevel,
                           State->diagBuf.str(),
                           Info.getRanges(),
-                          llvm::makeArrayRef(Info.getFixItHints(),
-                                             Info.getNumFixItHints()),
+                          Info.getFixItHints(),
                           &Info.getSourceManager(),
                           &Info);
 }
 
+static serialized_diags::Level getStableLevel(DiagnosticsEngine::Level Level) {
+  switch (Level) {
+#define CASE(X) case DiagnosticsEngine::X: return serialized_diags::X;
+  CASE(Ignored)
+  CASE(Note)
+  CASE(Remark)
+  CASE(Warning)
+  CASE(Error)
+  CASE(Fatal)
+#undef CASE
+  }
+
+  llvm_unreachable("invalid diagnostic level");
+}
+
 void SDiagsWriter::EmitDiagnosticMessage(SourceLocation Loc,
                                          PresumedLoc PLoc,
                                          DiagnosticsEngine::Level Level,
@@ -579,7 +593,7 @@ void SDiagsWriter::EmitDiagnosticMessage(SourceLocation Loc,
   // Emit the RECORD_DIAG record.
   Record.clear();
   Record.push_back(RECORD_DIAG);
-  Record.push_back(Level);
+  Record.push_back(getStableLevel(Level));
   AddLocToRecord(Loc, SM, PLoc, Record);
 
   if (const Diagnostic *Info = D.dyn_cast<const Diagnostic*>()) {
@@ -688,5 +702,5 @@ void SDiagsWriter::finish() {
   State->OS->write((char *)&State->Buffer.front(), State->Buffer.size());
   State->OS->flush();
 
-  State->OS.reset(0);
+  State->OS.reset();
 }
diff --git a/lib/Frontend/TextDiagnostic.cpp b/lib/Frontend/TextDiagnostic.cpp
index a2dc9537bc05..6e6f3dd1bfee 100644
--- a/lib/Frontend/TextDiagnostic.cpp
+++ b/lib/Frontend/TextDiagnostic.cpp
@@ -26,6 +26,8 @@ using namespace clang;
 
 static const enum raw_ostream::Colors noteColor =
   raw_ostream::BLACK;
+static const enum raw_ostream::Colors remarkColor =
+  raw_ostream::BLUE;
 static const enum raw_ostream::Colors fixitColor =
   raw_ostream::GREEN;
 static const enum raw_ostream::Colors caretColor =
@@ -312,14 +314,6 @@ private:
   SmallVector<int,200> m_byteToColumn;
   SmallVector<int,200> m_columnToByte;
 };
-
-// used in assert in selectInterestingSourceRegion()
-struct char_out_of_range {
-  const char lower,upper;
-  char_out_of_range(char lower, char upper) :
-    lower(lower), upper(upper) {}
-  bool operator()(char c) { return c < lower || upper < c; }
-};
 } // end anonymous namespace
 
 /// \brief When the source code line we want to print is too long for
@@ -339,7 +333,7 @@ static void selectInterestingSourceRegion(std::string &SourceLine,
   // No special characters are allowed in CaretLine.
   assert(CaretLine.end() ==
          std::find_if(CaretLine.begin(), CaretLine.end(),
-         char_out_of_range(' ','~')));
+                      [](char c) { return c < ' ' || '~' < c; }));
 
   // Find the slice that we need to display the full caret line
   // correctly.
@@ -695,8 +689,9 @@ TextDiagnostic::emitDiagnosticMessage(SourceLocation Loc,
   
   printDiagnosticLevel(OS, Level, DiagOpts->ShowColors,
                        DiagOpts->CLFallbackMode);
-  printDiagnosticMessage(OS, Level, Message,
-                         OS.tell() - StartOfLocationInfo,
+  printDiagnosticMessage(OS,
+                         /*IsSupplemental*/ Level == DiagnosticsEngine::Note,
+                         Message, OS.tell() - StartOfLocationInfo,
                          DiagOpts->MessageLength, DiagOpts->ShowColors);
 }
 
@@ -711,6 +706,7 @@ TextDiagnostic::printDiagnosticLevel(raw_ostream &OS,
     case DiagnosticsEngine::Ignored:
       llvm_unreachable("Invalid diagnostic type");
     case DiagnosticsEngine::Note:    OS.changeColor(noteColor, true); break;
+    case DiagnosticsEngine::Remark:  OS.changeColor(remarkColor, true); break;
     case DiagnosticsEngine::Warning: OS.changeColor(warningColor, true); break;
     case DiagnosticsEngine::Error:   OS.changeColor(errorColor, true); break;
     case DiagnosticsEngine::Fatal:   OS.changeColor(fatalColor, true); break;
@@ -721,6 +717,7 @@ TextDiagnostic::printDiagnosticLevel(raw_ostream &OS,
   case DiagnosticsEngine::Ignored:
     llvm_unreachable("Invalid diagnostic type");
   case DiagnosticsEngine::Note:    OS << "note"; break;
+  case DiagnosticsEngine::Remark:  OS << "remark"; break;
   case DiagnosticsEngine::Warning: OS << "warning"; break;
   case DiagnosticsEngine::Error:   OS << "error"; break;
   case DiagnosticsEngine::Fatal:   OS << "fatal error"; break;
@@ -739,24 +736,18 @@ TextDiagnostic::printDiagnosticLevel(raw_ostream &OS,
     OS.resetColor();
 }
 
-/*static*/ void
-TextDiagnostic::printDiagnosticMessage(raw_ostream &OS,
-                                       DiagnosticsEngine::Level Level,
-                                       StringRef Message,
-                                       unsigned CurrentColumn, unsigned Columns,
-                                       bool ShowColors) {
+/*static*/
+void TextDiagnostic::printDiagnosticMessage(raw_ostream &OS,
+                                            bool IsSupplemental,
+                                            StringRef Message,
+                                            unsigned CurrentColumn,
+                                            unsigned Columns, bool ShowColors) {
   bool Bold = false;
-  if (ShowColors) {
-    // Print warnings, errors and fatal errors in bold, no color
-    switch (Level) {
-    case DiagnosticsEngine::Warning:
-    case DiagnosticsEngine::Error:
-    case DiagnosticsEngine::Fatal:
-      OS.changeColor(savedColor, true);
-      Bold = true;
-      break;
-    default: break; //don't bold notes
-    }
+  if (ShowColors && !IsSupplemental) {
+    // Print primary diagnostic messages in bold and without color, to visually
+    // indicate the transition from continuation notes and other output.
+    OS.changeColor(savedColor, true);
+    Bold = true;
   }
 
   if (Columns)
@@ -787,7 +778,7 @@ void TextDiagnostic::emitDiagnosticLoc(SourceLocation Loc, PresumedLoc PLoc,
     FileID FID = SM.getFileID(Loc);
     if (!FID.isInvalid()) {
       const FileEntry* FE = SM.getFileEntryForID(FID);
-      if (FE && FE->getName()) {
+      if (FE && FE->isValid()) {
         OS << FE->getName();
         if (FE->isInPCH())
           OS << " (in PCH)";
@@ -816,7 +807,10 @@ void TextDiagnostic::emitDiagnosticLoc(SourceLocation Loc, PresumedLoc PLoc,
     if (unsigned ColNo = PLoc.getColumn()) {
       if (DiagOpts->getFormat() == DiagnosticOptions::Msvc) {
         OS << ',';
-        ColNo--;
+        // Visual Studio 2010 or earlier expects column number to be off by one
+        if (LangOpts.MSCompatibilityVersion &&
+            LangOpts.MSCompatibilityVersion < 170000000)
+          ColNo--;
       } else
         OS << ':';
       OS << ColNo;
@@ -877,12 +871,6 @@ void TextDiagnostic::emitDiagnosticLoc(SourceLocation Loc, PresumedLoc PLoc,
   OS << ' ';
 }
 
-void TextDiagnostic::emitBasicNote(StringRef Message) {
-  // FIXME: Emit this as a real note diagnostic.
-  // FIXME: Format an actual diagnostic rather than a hard coded string.
-  OS << "note: " << Message << "\n";
-}
-
 void TextDiagnostic::emitIncludeLocation(SourceLocation Loc,
                                          PresumedLoc PLoc,
                                          const SourceManager &SM) {
@@ -1143,7 +1131,7 @@ void TextDiagnostic::emitSnippetAndCaret(
   std::string FixItInsertionLine = buildFixItInsertionLine(LineNo,
                                                            sourceColMap,
                                                            Hints, SM,
-                                                           DiagOpts.getPtr());
+                                                           DiagOpts.get());
 
   // If the source line is too long for our terminal, select only the
   // "interesting" source region within that line.
diff --git a/lib/Frontend/TextDiagnosticBuffer.cpp b/lib/Frontend/TextDiagnosticBuffer.cpp
index 5821436a306f..9c6bebb07210 100644
--- a/lib/Frontend/TextDiagnosticBuffer.cpp
+++ b/lib/Frontend/TextDiagnosticBuffer.cpp
@@ -35,6 +35,9 @@ void TextDiagnosticBuffer::HandleDiagnostic(DiagnosticsEngine::Level Level,
   case DiagnosticsEngine::Warning:
     Warnings.push_back(std::make_pair(Info.getLocation(), Buf.str()));
     break;
+  case DiagnosticsEngine::Remark:
+    Remarks.push_back(std::make_pair(Info.getLocation(), Buf.str()));
+    break;
   case DiagnosticsEngine::Error:
   case DiagnosticsEngine::Fatal:
     Errors.push_back(std::make_pair(Info.getLocation(), Buf.str()));
@@ -42,36 +45,19 @@ void TextDiagnosticBuffer::HandleDiagnostic(DiagnosticsEngine::Level Level,
   }
 }
 
-/// \brief Escape diagnostic texts to avoid problems when they are fed into the
-/// diagnostic formatter a second time.
-static StringRef escapeDiag(StringRef Str, SmallVectorImpl<char> &Buf) {
-  size_t Pos = Str.find('%');
-  if (Pos == StringRef::npos)
-    return Str;
-
-  // We found a '%'. Replace this and all following '%' with '%%'.
-  Buf.clear();
-  Buf.append(Str.data(), Str.data() + Pos);
-  for (size_t I = Pos, E = Str.size(); I != E; ++I) {
-    if (Str[I] == '%')
-      Buf.push_back('%');
-    Buf.push_back(Str[I]);
-  }
-
-  return StringRef(Buf.data(), Buf.size());
-}
-
 void TextDiagnosticBuffer::FlushDiagnostics(DiagnosticsEngine &Diags) const {
-  SmallVector<char, 64> Buf;
   // FIXME: Flush the diagnostics in order.
   for (const_iterator it = err_begin(), ie = err_end(); it != ie; ++it)
-    Diags.Report(Diags.getCustomDiagID(DiagnosticsEngine::Error,
-                                       escapeDiag(it->second, Buf)));
+    Diags.Report(Diags.getCustomDiagID(DiagnosticsEngine::Error, "%0"))
+        << it->second;
   for (const_iterator it = warn_begin(), ie = warn_end(); it != ie; ++it)
-    Diags.Report(Diags.getCustomDiagID(DiagnosticsEngine::Warning,
-                                       escapeDiag(it->second, Buf)));
+    Diags.Report(Diags.getCustomDiagID(DiagnosticsEngine::Warning, "%0"))
+        << it->second;
+  for (const_iterator it = remark_begin(), ie = remark_end(); it != ie; ++it)
+    Diags.Report(Diags.getCustomDiagID(DiagnosticsEngine::Remark, "%0"))
+        << it->second;
   for (const_iterator it = note_begin(), ie = note_end(); it != ie; ++it)
-    Diags.Report(Diags.getCustomDiagID(DiagnosticsEngine::Note,
-                                       escapeDiag(it->second, Buf)));
+    Diags.Report(Diags.getCustomDiagID(DiagnosticsEngine::Note, "%0"))
+        << it->second;
 }
 
diff --git a/lib/Frontend/TextDiagnosticPrinter.cpp b/lib/Frontend/TextDiagnosticPrinter.cpp
index 994a8f74ed46..66b46b7814eb 100644
--- a/lib/Frontend/TextDiagnosticPrinter.cpp
+++ b/lib/Frontend/TextDiagnosticPrinter.cpp
@@ -43,7 +43,7 @@ void TextDiagnosticPrinter::BeginSourceFile(const LangOptions &LO,
 }
 
 void TextDiagnosticPrinter::EndSourceFile() {
-  TextDiag.reset(0);
+  TextDiag.reset();
 }
 
 /// \brief Print any diagnostic option information to a raw_ostream.
@@ -81,7 +81,11 @@ static void printDiagnosticOptions(raw_ostream &OS,
 
     StringRef Opt = DiagnosticIDs::getWarningOptionForDiag(Info.getID());
     if (!Opt.empty()) {
-      OS << (Started ? "," : " [") << "-W" << Opt;
+      OS << (Started ? "," : " [")
+         << (Level == DiagnosticsEngine::Remark ? "-R" : "-W") << Opt;
+      StringRef OptValue = Info.getDiags()->getFlagValue();
+      if (!OptValue.empty())
+        OS << "=" << OptValue;
       Started = true;
     }
   }
@@ -150,8 +154,7 @@ void TextDiagnosticPrinter::HandleDiagnostic(DiagnosticsEngine::Level Level,
 
   TextDiag->emitDiagnostic(Info.getLocation(), Level, DiagMessageStream.str(),
                            Info.getRanges(),
-                           llvm::makeArrayRef(Info.getFixItHints(),
-                                              Info.getNumFixItHints()),
+                           Info.getFixItHints(),
                            &Info.getSourceManager());
 
   OS.flush();
diff --git a/lib/Frontend/VerifyDiagnosticConsumer.cpp b/lib/Frontend/VerifyDiagnosticConsumer.cpp
index 045e60add1fc..b50950e9b300 100644
--- a/lib/Frontend/VerifyDiagnosticConsumer.cpp
+++ b/lib/Frontend/VerifyDiagnosticConsumer.cpp
@@ -30,8 +30,9 @@ typedef VerifyDiagnosticConsumer::ExpectedData ExpectedData;
 VerifyDiagnosticConsumer::VerifyDiagnosticConsumer(DiagnosticsEngine &_Diags)
   : Diags(_Diags),
     PrimaryClient(Diags.getClient()), OwnsPrimaryClient(Diags.ownsClient()),
-    Buffer(new TextDiagnosticBuffer()), CurrentPreprocessor(0),
-    LangOpts(0), SrcManager(0), ActiveSourceFiles(0), Status(HasNoDirectives)
+    Buffer(new TextDiagnosticBuffer()), CurrentPreprocessor(nullptr),
+    LangOpts(nullptr), SrcManager(nullptr), ActiveSourceFiles(0),
+    Status(HasNoDirectives)
 {
   Diags.takeClient();
   if (Diags.hasSourceManager())
@@ -41,7 +42,7 @@ VerifyDiagnosticConsumer::VerifyDiagnosticConsumer(DiagnosticsEngine &_Diags)
 VerifyDiagnosticConsumer::~VerifyDiagnosticConsumer() {
   assert(!ActiveSourceFiles && "Incomplete parsing of source files!");
   assert(!CurrentPreprocessor && "CurrentPreprocessor should be invalid!");
-  SrcManager = 0;
+  SrcManager = nullptr;
   CheckDiagnostics();  
   Diags.takeClient();
   if (OwnsPrimaryClient)
@@ -104,8 +105,8 @@ void VerifyDiagnosticConsumer::EndSourceFile() {
 
     // Check diagnostics once last file completed.
     CheckDiagnostics();
-    CurrentPreprocessor = 0;
-    LangOpts = 0;
+    CurrentPreprocessor = nullptr;
+    LangOpts = nullptr;
   }
 }
 
@@ -163,15 +164,16 @@ namespace {
 class StandardDirective : public Directive {
 public:
   StandardDirective(SourceLocation DirectiveLoc, SourceLocation DiagnosticLoc,
-                    StringRef Text, unsigned Min, unsigned Max)
-    : Directive(DirectiveLoc, DiagnosticLoc, Text, Min, Max) { }
+                    bool MatchAnyLine, StringRef Text, unsigned Min,
+                    unsigned Max)
+    : Directive(DirectiveLoc, DiagnosticLoc, MatchAnyLine, Text, Min, Max) { }
 
-  virtual bool isValid(std::string &Error) {
+  bool isValid(std::string &Error) override {
     // all strings are considered valid; even empty ones
     return true;
   }
 
-  virtual bool match(StringRef S) {
+  bool match(StringRef S) override {
     return S.find(Text) != StringRef::npos;
   }
 };
@@ -181,16 +183,18 @@ public:
 class RegexDirective : public Directive {
 public:
   RegexDirective(SourceLocation DirectiveLoc, SourceLocation DiagnosticLoc,
-                 StringRef Text, unsigned Min, unsigned Max)
-    : Directive(DirectiveLoc, DiagnosticLoc, Text, Min, Max), Regex(Text) { }
+                 bool MatchAnyLine, StringRef Text, unsigned Min, unsigned Max,
+                 StringRef RegexStr)
+    : Directive(DirectiveLoc, DiagnosticLoc, MatchAnyLine, Text, Min, Max),
+      Regex(RegexStr) { }
 
-  virtual bool isValid(std::string &Error) {
+  bool isValid(std::string &Error) override {
     if (Regex.isValid(Error))
       return true;
     return false;
   }
 
-  virtual bool match(StringRef S) {
+  bool match(StringRef S) override {
     return Regex.match(S);
   }
 
@@ -202,7 +206,7 @@ class ParseHelper
 {
 public:
   ParseHelper(StringRef S)
-    : Begin(S.begin()), End(S.end()), C(Begin), P(Begin), PEnd(NULL) { }
+    : Begin(S.begin()), End(S.end()), C(Begin), P(Begin), PEnd(nullptr) {}
 
   // Return true if string literal is next.
   bool Next(StringRef S) {
@@ -240,7 +244,7 @@ public:
       if (!EnsureStartOfWord
             // Check if string literal starts a new word.
             || P == Begin || isWhitespace(P[-1])
-            // Or it could be preceeded by the start of a comment.
+            // Or it could be preceded by the start of a comment.
             || (P > (Begin + 1) && (P[-1] == '/' || P[-1] == '*')
                                 &&  P[-2] == '/'))
         return true;
@@ -249,6 +253,30 @@ public:
     return false;
   }
 
+  // Return true if a CloseBrace that closes the OpenBrace at the current nest
+  // level is found. When true, P marks begin-position of CloseBrace.
+  bool SearchClosingBrace(StringRef OpenBrace, StringRef CloseBrace) {
+    unsigned Depth = 1;
+    P = C;
+    while (P < End) {
+      StringRef S(P, End - P);
+      if (S.startswith(OpenBrace)) {
+        ++Depth;
+        P += OpenBrace.size();
+      } else if (S.startswith(CloseBrace)) {
+        --Depth;
+        if (Depth == 0) {
+          PEnd = P + CloseBrace.size();
+          return true;
+        }
+        P += CloseBrace.size();
+      } else {
+        ++P;
+      }
+    }
+    return false;
+  }
+
   // Advance 1-past previous next/search.
   // Behavior is undefined if previous next/search failed.
   bool Advance() {
@@ -301,13 +329,15 @@ static bool ParseDirective(StringRef S, ExpectedData *ED, SourceManager &SM,
     PH.Advance();
 
     // Next token: { error | warning | note }
-    DirectiveList* DL = NULL;
+    DirectiveList *DL = nullptr;
     if (PH.Next("error"))
-      DL = ED ? &ED->Errors : NULL;
+      DL = ED ? &ED->Errors : nullptr;
     else if (PH.Next("warning"))
-      DL = ED ? &ED->Warnings : NULL;
+      DL = ED ? &ED->Warnings : nullptr;
+    else if (PH.Next("remark"))
+      DL = ED ? &ED->Remarks : nullptr;
     else if (PH.Next("note"))
-      DL = ED ? &ED->Notes : NULL;
+      DL = ED ? &ED->Notes : nullptr;
     else if (PH.Next("no-diagnostics")) {
       if (Status == VerifyDiagnosticConsumer::HasOtherExpectedDirectives)
         Diags.Report(Pos, diag::err_verify_invalid_no_diags)
@@ -344,6 +374,7 @@ static bool ParseDirective(StringRef S, ExpectedData *ED, SourceManager &SM,
 
     // Next optional token: @
     SourceLocation ExpectedLoc;
+    bool MatchAnyLine = false;
     if (!PH.Next("@")) {
       ExpectedLoc = Pos;
     } else {
@@ -371,8 +402,8 @@ static bool ParseDirective(StringRef S, ExpectedData *ED, SourceManager &SM,
 
         // Lookup file via Preprocessor, like a #include.
         const DirectoryLookup *CurDir;
-        const FileEntry *FE = PP->LookupFile(Pos, Filename, false, NULL, CurDir,
-                                             NULL, NULL, 0);
+        const FileEntry *FE = PP->LookupFile(Pos, Filename, false, nullptr,
+                                             CurDir, nullptr, nullptr, nullptr);
         if (!FE) {
           Diags.Report(Pos.getLocWithOffset(PH.C-PH.Begin),
                        diag::err_verify_missing_file) << Filename << KindStr;
@@ -384,6 +415,10 @@ static bool ParseDirective(StringRef S, ExpectedData *ED, SourceManager &SM,
 
         if (PH.Next(Line) && Line > 0)
           ExpectedLoc = SM.translateFileLineCol(FE, Line, 1);
+        else if (PH.Next("*")) {
+          MatchAnyLine = true;
+          ExpectedLoc = SM.translateFileLineCol(FE, 1, 1);
+        }
       }
 
       if (ExpectedLoc.isInvalid()) {
@@ -437,7 +472,7 @@ static bool ParseDirective(StringRef S, ExpectedData *ED, SourceManager &SM,
     const char* const ContentBegin = PH.C; // mark content begin
 
     // Search for token: }}
-    if (!PH.Search("}}")) {
+    if (!PH.SearchClosingBrace("{{", "}}")) {
       Diags.Report(Pos.getLocWithOffset(PH.C-PH.Begin),
                    diag::err_verify_missing_end) << KindStr;
       continue;
@@ -459,12 +494,21 @@ static bool ParseDirective(StringRef S, ExpectedData *ED, SourceManager &SM,
     if (Text.empty())
       Text.assign(ContentBegin, ContentEnd);
 
+    // Check that regex directives contain at least one regex.
+    if (RegexKind && Text.find("{{") == StringRef::npos) {
+      Diags.Report(Pos.getLocWithOffset(ContentBegin-PH.Begin),
+                   diag::err_verify_missing_regex) << Text;
+      return false;
+    }
+
     // Construct new directive.
-    Directive *D = Directive::create(RegexKind, Pos, ExpectedLoc, Text,
-                                     Min, Max);
+    std::unique_ptr<Directive> D(
+        Directive::create(RegexKind, Pos, ExpectedLoc, MatchAnyLine, Text,
+                          Min, Max));
+
     std::string Error;
     if (D->isValid(Error)) {
-      DL->push_back(D);
+      DL->push_back(D.release());
       FoundDirective = true;
     } else {
       Diags.Report(Pos.getLocWithOffset(ContentBegin-PH.Begin),
@@ -562,7 +606,8 @@ static bool findDirectives(SourceManager &SM, FileID FID,
     if (Comment.empty()) continue;
 
     // Find first directive.
-    if (ParseDirective(Comment, 0, SM, 0, Tok.getLocation(), Status))
+    if (ParseDirective(Comment, nullptr, SM, nullptr, Tok.getLocation(),
+                       Status))
       return true;
   }
   return false;
@@ -608,8 +653,11 @@ static unsigned PrintExpected(DiagnosticsEngine &Diags, SourceManager &SourceMgr
   llvm::raw_svector_ostream OS(Fmt);
   for (DirectiveList::iterator I = DL.begin(), E = DL.end(); I != E; ++I) {
     Directive &D = **I;
-    OS << "\n  File " << SourceMgr.getFilename(D.DiagnosticLoc)
-          << " Line " << SourceMgr.getPresumedLineNumber(D.DiagnosticLoc);
+    OS << "\n  File " << SourceMgr.getFilename(D.DiagnosticLoc);
+    if (D.MatchAnyLine)
+      OS << " Line *";
+    else
+      OS << " Line " << SourceMgr.getPresumedLineNumber(D.DiagnosticLoc);
     if (D.DirectiveLoc != D.DiagnosticLoc)
       OS << " (directive at "
          << SourceMgr.getFilename(D.DirectiveLoc) << ':'
@@ -656,9 +704,11 @@ static unsigned CheckLists(DiagnosticsEngine &Diags, SourceManager &SourceMgr,
     for (unsigned i = 0; i < D.Max; ++i) {
       DiagList::iterator II, IE;
       for (II = Right.begin(), IE = Right.end(); II != IE; ++II) {
-        unsigned LineNo2 = SourceMgr.getPresumedLineNumber(II->first);
-        if (LineNo1 != LineNo2)
-          continue;
+        if (!D.MatchAnyLine) {
+          unsigned LineNo2 = SourceMgr.getPresumedLineNumber(II->first);
+          if (LineNo1 != LineNo2)
+            continue;
+        }
 
         if (!IsFromSameFile(SourceMgr, D.DiagnosticLoc, II->first))
           continue;
@@ -705,6 +755,10 @@ static unsigned CheckResults(DiagnosticsEngine &Diags, SourceManager &SourceMgr,
   NumProblems += CheckLists(Diags, SourceMgr, "warning", ED.Warnings,
                             Buffer.warn_begin(), Buffer.warn_end());
 
+  // See if there are remark mismatches.
+  NumProblems += CheckLists(Diags, SourceMgr, "remark", ED.Remarks,
+                            Buffer.remark_begin(), Buffer.remark_end());
+
   // See if there are note mismatches.
   NumProblems += CheckLists(Diags, SourceMgr, "note", ED.Notes,
                             Buffer.note_begin(), Buffer.note_end());
@@ -802,11 +856,11 @@ void VerifyDiagnosticConsumer::CheckDiagnostics() {
     // Check that the expected diagnostics occurred.
     NumErrors += CheckResults(Diags, *SrcManager, *Buffer, ED);
   } else {
-    NumErrors += (PrintUnexpected(Diags, 0, Buffer->err_begin(),
+    NumErrors += (PrintUnexpected(Diags, nullptr, Buffer->err_begin(),
                                   Buffer->err_end(), "error") +
-                  PrintUnexpected(Diags, 0, Buffer->warn_begin(),
+                  PrintUnexpected(Diags, nullptr, Buffer->warn_begin(),
                                   Buffer->warn_end(), "warn") +
-                  PrintUnexpected(Diags, 0, Buffer->note_begin(),
+                  PrintUnexpected(Diags, nullptr, Buffer->note_begin(),
                                   Buffer->note_end(), "note"));
   }
 
@@ -815,15 +869,39 @@ void VerifyDiagnosticConsumer::CheckDiagnostics() {
 
   // Reset the buffer, we have processed all the diagnostics in it.
   Buffer.reset(new TextDiagnosticBuffer());
-  ED.Errors.clear();
-  ED.Warnings.clear();
-  ED.Notes.clear();
+  ED.Reset();
 }
 
 Directive *Directive::create(bool RegexKind, SourceLocation DirectiveLoc,
-                             SourceLocation DiagnosticLoc, StringRef Text,
-                             unsigned Min, unsigned Max) {
-  if (RegexKind)
-    return new RegexDirective(DirectiveLoc, DiagnosticLoc, Text, Min, Max);
-  return new StandardDirective(DirectiveLoc, DiagnosticLoc, Text, Min, Max);
+                             SourceLocation DiagnosticLoc, bool MatchAnyLine,
+                             StringRef Text, unsigned Min, unsigned Max) {
+  if (!RegexKind)
+    return new StandardDirective(DirectiveLoc, DiagnosticLoc, MatchAnyLine,
+                                 Text, Min, Max);
+
+  // Parse the directive into a regular expression.
+  std::string RegexStr;
+  StringRef S = Text;
+  while (!S.empty()) {
+    if (S.startswith("{{")) {
+      S = S.drop_front(2);
+      size_t RegexMatchLength = S.find("}}");
+      assert(RegexMatchLength != StringRef::npos);
+      // Append the regex, enclosed in parentheses.
+      RegexStr += "(";
+      RegexStr.append(S.data(), RegexMatchLength);
+      RegexStr += ")";
+      S = S.drop_front(RegexMatchLength + 2);
+    } else {
+      size_t VerbatimMatchLength = S.find("{{");
+      if (VerbatimMatchLength == StringRef::npos)
+        VerbatimMatchLength = S.size();
+      // Escape and append the fixed string.
+      RegexStr += llvm::Regex::escape(S.substr(0, VerbatimMatchLength));
+      S = S.drop_front(VerbatimMatchLength);
+    }
+  }
+
+  return new RegexDirective(DirectiveLoc, DiagnosticLoc, MatchAnyLine, Text,
+                            Min, Max, RegexStr);
 }
diff --git a/lib/Frontend/Warnings.cpp b/lib/Frontend/Warnings.cpp
deleted file mode 100644
index 767096a1c990..000000000000
--- a/lib/Frontend/Warnings.cpp
+++ /dev/null
@@ -1,203 +0,0 @@
-//===--- Warnings.cpp - C-Language Front-end ------------------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// Command line warning options handler.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file is responsible for handling all warning options. This includes
-// a number of -Wfoo options and their variants, which are driven by TableGen-
-// generated data, and the special cases -pedantic, -pedantic-errors, -w,
-// -Werror and -Wfatal-errors.
-//
-// Each warning option controls any number of actual warnings.
-// Given a warning option 'foo', the following are valid:
-//    -Wfoo, -Wno-foo, -Werror=foo, -Wfatal-errors=foo
-//
-#include "clang/Frontend/Utils.h"
-#include "clang/Basic/Diagnostic.h"
-#include "clang/Basic/DiagnosticOptions.h"
-#include "clang/Frontend/FrontendDiagnostic.h"
-#include "clang/Lex/LexDiagnostic.h"
-#include "clang/Sema/SemaDiagnostic.h"
-#include <algorithm>
-#include <cstring>
-#include <utility>
-using namespace clang;
-
-// EmitUnknownDiagWarning - Emit a warning and typo hint for unknown warning
-// opts
-static void EmitUnknownDiagWarning(DiagnosticsEngine &Diags,
-                                  StringRef Prefix, StringRef Opt,
-                                  bool isPositive) {
-  StringRef Suggestion = DiagnosticIDs::getNearestWarningOption(Opt);
-  if (!Suggestion.empty())
-    Diags.Report(isPositive? diag::warn_unknown_warning_option_suggest :
-                             diag::warn_unknown_negative_warning_option_suggest)
-      << (Prefix.str() += Opt) << (Prefix.str() += Suggestion);
-  else
-    Diags.Report(isPositive? diag::warn_unknown_warning_option :
-                             diag::warn_unknown_negative_warning_option)
-      << (Prefix.str() += Opt);
-}
-
-void clang::ProcessWarningOptions(DiagnosticsEngine &Diags,
-                                  const DiagnosticOptions &Opts,
-                                  bool ReportDiags) {
-  Diags.setSuppressSystemWarnings(true);  // Default to -Wno-system-headers
-  Diags.setIgnoreAllWarnings(Opts.IgnoreWarnings);
-  Diags.setShowOverloads(Opts.getShowOverloads());
-
-  Diags.setElideType(Opts.ElideType);
-  Diags.setPrintTemplateTree(Opts.ShowTemplateTree);
-  Diags.setShowColors(Opts.ShowColors);
- 
-  // Handle -ferror-limit
-  if (Opts.ErrorLimit)
-    Diags.setErrorLimit(Opts.ErrorLimit);
-  if (Opts.TemplateBacktraceLimit)
-    Diags.setTemplateBacktraceLimit(Opts.TemplateBacktraceLimit);
-  if (Opts.ConstexprBacktraceLimit)
-    Diags.setConstexprBacktraceLimit(Opts.ConstexprBacktraceLimit);
-
-  // If -pedantic or -pedantic-errors was specified, then we want to map all
-  // extension diagnostics onto WARNING or ERROR unless the user has futz'd
-  // around with them explicitly.
-  if (Opts.PedanticErrors)
-    Diags.setExtensionHandlingBehavior(DiagnosticsEngine::Ext_Error);
-  else if (Opts.Pedantic)
-    Diags.setExtensionHandlingBehavior(DiagnosticsEngine::Ext_Warn);
-  else
-    Diags.setExtensionHandlingBehavior(DiagnosticsEngine::Ext_Ignore);
-
-  SmallVector<diag::kind, 10> _Diags;
-  const IntrusiveRefCntPtr< DiagnosticIDs > DiagIDs =
-    Diags.getDiagnosticIDs();
-  // We parse the warning options twice.  The first pass sets diagnostic state,
-  // while the second pass reports warnings/errors.  This has the effect that
-  // we follow the more canonical "last option wins" paradigm when there are 
-  // conflicting options.
-  for (unsigned Report = 0, ReportEnd = 2; Report != ReportEnd; ++Report) {
-    bool SetDiagnostic = (Report == 0);
-
-    // If we've set the diagnostic state and are not reporting diagnostics then
-    // we're done.
-    if (!SetDiagnostic && !ReportDiags)
-      break;
-
-    for (unsigned i = 0, e = Opts.Warnings.size(); i != e; ++i) {
-      StringRef Opt = Opts.Warnings[i];
-      StringRef OrigOpt = Opts.Warnings[i];
-
-      // Treat -Wformat=0 as an alias for -Wno-format.
-      if (Opt == "format=0")
-        Opt = "no-format";
-
-      // Check to see if this warning starts with "no-", if so, this is a
-      // negative form of the option.
-      bool isPositive = true;
-      if (Opt.startswith("no-")) {
-        isPositive = false;
-        Opt = Opt.substr(3);
-      }
-
-      // Figure out how this option affects the warning.  If -Wfoo, map the
-      // diagnostic to a warning, if -Wno-foo, map it to ignore.
-      diag::Mapping Mapping = isPositive ? diag::MAP_WARNING : diag::MAP_IGNORE;
-      
-      // -Wsystem-headers is a special case, not driven by the option table.  It
-      // cannot be controlled with -Werror.
-      if (Opt == "system-headers") {
-        if (SetDiagnostic)
-          Diags.setSuppressSystemWarnings(!isPositive);
-        continue;
-      }
-      
-      // -Weverything is a special case as well.  It implicitly enables all
-      // warnings, including ones not explicitly in a warning group.
-      if (Opt == "everything") {
-        if (SetDiagnostic) {
-          if (isPositive) {
-            Diags.setEnableAllWarnings(true);
-          } else {
-            Diags.setEnableAllWarnings(false);
-            Diags.setMappingToAllDiagnostics(diag::MAP_IGNORE);
-          }
-        }
-        continue;
-      }
-      
-      // -Werror/-Wno-error is a special case, not controlled by the option 
-      // table. It also has the "specifier" form of -Werror=foo and -Werror-foo.
-      if (Opt.startswith("error")) {
-        StringRef Specifier;
-        if (Opt.size() > 5) {  // Specifier must be present.
-          if ((Opt[5] != '=' && Opt[5] != '-') || Opt.size() == 6) {
-            if (Report)
-              Diags.Report(diag::warn_unknown_warning_specifier)
-                << "-Werror" << ("-W" + OrigOpt.str());
-            continue;
-          }
-          Specifier = Opt.substr(6);
-        }
-        
-        if (Specifier.empty()) {
-          if (SetDiagnostic)
-            Diags.setWarningsAsErrors(isPositive);
-          continue;
-        }
-        
-        if (SetDiagnostic) {
-          // Set the warning as error flag for this specifier.
-          Diags.setDiagnosticGroupWarningAsError(Specifier, isPositive);
-        } else if (DiagIDs->getDiagnosticsInGroup(Specifier, _Diags)) {
-          EmitUnknownDiagWarning(Diags, "-Werror=", Specifier, isPositive);
-        }
-        continue;
-      }
-      
-      // -Wfatal-errors is yet another special case.
-      if (Opt.startswith("fatal-errors")) {
-        StringRef Specifier;
-        if (Opt.size() != 12) {
-          if ((Opt[12] != '=' && Opt[12] != '-') || Opt.size() == 13) {
-            if (Report)
-              Diags.Report(diag::warn_unknown_warning_specifier)
-                << "-Wfatal-errors" << ("-W" + OrigOpt.str());
-            continue;
-          }
-          Specifier = Opt.substr(13);
-        }
-
-        if (Specifier.empty()) {
-          if (SetDiagnostic)
-            Diags.setErrorsAsFatal(isPositive);
-          continue;
-        }
-        
-        if (SetDiagnostic) {
-          // Set the error as fatal flag for this specifier.
-          Diags.setDiagnosticGroupErrorAsFatal(Specifier, isPositive);
-        } else if (DiagIDs->getDiagnosticsInGroup(Specifier, _Diags)) {
-          EmitUnknownDiagWarning(Diags, "-Wfatal-errors=", Specifier,
-                                 isPositive);
-        }
-        continue;
-      }
-      
-      if (Report) {
-        if (DiagIDs->getDiagnosticsInGroup(Opt, _Diags))
-          EmitUnknownDiagWarning(Diags, isPositive ? "-W" : "-Wno-", Opt,
-                                 isPositive);
-      } else {
-        Diags.setDiagnosticGroupMapping(Opt, Mapping);
-      }
-    }
-  }
-}