vendor/clang/clang-trunk-r375505vendor/clang

29 files changed, 664 insertions, 671 deletions

diff --git a/lib/Frontend/ASTConsumers.cpp b/lib/Frontend/ASTConsumers.cpp
index 26154ee2e856c..043b2541b8f87 100644
--- a/lib/Frontend/ASTConsumers.cpp
+++ b/lib/Frontend/ASTConsumers.cpp
@@ -139,7 +139,7 @@ namespace {
 std::unique_ptr<ASTConsumer>
 clang::CreateASTPrinter(std::unique_ptr<raw_ostream> Out,
                         StringRef FilterString) {
-  return llvm::make_unique<ASTPrinter>(std::move(Out), ASTPrinter::Print,
+  return std::make_unique<ASTPrinter>(std::move(Out), ASTPrinter::Print,
                                        ADOF_Default, FilterString);
 }
 
@@ -148,7 +148,7 @@ clang::CreateASTDumper(std::unique_ptr<raw_ostream> Out, StringRef FilterString,
                        bool DumpDecls, bool Deserialize, bool DumpLookups,
                        ASTDumpOutputFormat Format) {
   assert((DumpDecls || Deserialize || DumpLookups) && "nothing to dump");
-  return llvm::make_unique<ASTPrinter>(std::move(Out),
+  return std::make_unique<ASTPrinter>(std::move(Out),
                                        Deserialize ? ASTPrinter::DumpFull :
                                        DumpDecls ? ASTPrinter::Dump :
                                        ASTPrinter::None, Format,
@@ -156,7 +156,7 @@ clang::CreateASTDumper(std::unique_ptr<raw_ostream> Out, StringRef FilterString,
 }
 
 std::unique_ptr<ASTConsumer> clang::CreateASTDeclNodeLister() {
-  return llvm::make_unique<ASTDeclNodeLister>(nullptr);
+  return std::make_unique<ASTDeclNodeLister>(nullptr);
 }
 
 //===----------------------------------------------------------------------===//
@@ -193,5 +193,5 @@ void ASTViewer::HandleTopLevelSingleDecl(Decl *D) {
 }
 
 std::unique_ptr<ASTConsumer> clang::CreateASTViewer() {
-  return llvm::make_unique<ASTViewer>();
+  return std::make_unique<ASTViewer>();
 }
diff --git a/lib/Frontend/ASTUnit.cpp b/lib/Frontend/ASTUnit.cpp
index 7445a94cfe591..f5e291b7fe17e 100644
--- a/lib/Frontend/ASTUnit.cpp
+++ b/lib/Frontend/ASTUnit.cpp
@@ -30,6 +30,7 @@
 #include "clang/Basic/IdentifierTable.h"
 #include "clang/Basic/LLVM.h"
 #include "clang/Basic/LangOptions.h"
+#include "clang/Basic/LangStandard.h"
 #include "clang/Basic/Module.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/SourceManager.h"
@@ -83,8 +84,8 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/FileSystem.h"
+#include "llvm/Support/FileUtilities.h"
 #include "llvm/Support/MemoryBuffer.h"
-#include "llvm/Support/Mutex.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/raw_ostream.h"
@@ -95,6 +96,7 @@
 #include <cstdio>
 #include <cstdlib>
 #include <memory>
+#include <mutex>
 #include <string>
 #include <tuple>
 #include <utility>
@@ -435,7 +437,6 @@ void ASTUnit::CacheCodeCompletionResults() {
           | (1LL << CodeCompletionContext::CCC_UnionTag)
           | (1LL << CodeCompletionContext::CCC_ClassOrStructTag)
           | (1LL << CodeCompletionContext::CCC_Type)
-          | (1LL << CodeCompletionContext::CCC_Symbol)
           | (1LL << CodeCompletionContext::CCC_SymbolOrNewName)
           | (1LL << CodeCompletionContext::CCC_ParenthesizedExpression);
 
@@ -819,7 +820,7 @@ std::unique_ptr<ASTUnit> ASTUnit::LoadFromASTFile(
       /*isysroot=*/"",
       /*DisableValidation=*/disableValid, AllowPCHWithCompilerErrors);
 
-  AST->Reader->setListener(llvm::make_unique<ASTInfoCollector>(
+  AST->Reader->setListener(std::make_unique<ASTInfoCollector>(
       *AST->PP, AST->Ctx.get(), *AST->HSOpts, *AST->PPOpts, *AST->LangOpts,
       AST->TargetOpts, AST->Target, Counter));
 
@@ -999,9 +1000,9 @@ public:
   std::unique_ptr<ASTConsumer> CreateASTConsumer(CompilerInstance &CI,
                                                  StringRef InFile) override {
     CI.getPreprocessor().addPPCallbacks(
-        llvm::make_unique<MacroDefinitionTrackerPPCallbacks>(
+        std::make_unique<MacroDefinitionTrackerPPCallbacks>(
                                            Unit.getCurrentTopLevelHashValue()));
-    return llvm::make_unique<TopLevelDeclTrackerConsumer>(
+    return std::make_unique<TopLevelDeclTrackerConsumer>(
         Unit, Unit.getCurrentTopLevelHashValue());
   }
 
@@ -1049,7 +1050,7 @@ public:
   }
 
   std::unique_ptr<PPCallbacks> createPPCallbacks() override {
-    return llvm::make_unique<MacroDefinitionTrackerPPCallbacks>(Hash);
+    return std::make_unique<MacroDefinitionTrackerPPCallbacks>(Hash);
   }
 
 private:
@@ -1154,7 +1155,7 @@ bool ASTUnit::Parse(std::shared_ptr<PCHContainerOperations> PCHContainerOps,
              InputKind::Source &&
          "FIXME: AST inputs not yet supported here!");
   assert(Clang->getFrontendOpts().Inputs[0].getKind().getLanguage() !=
-             InputKind::LLVM_IR &&
+             Language::LLVM_IR &&
          "IR inputs not support here!");
 
   // Configure the various subsystems.
@@ -1587,7 +1588,7 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocationAction(
              InputKind::Source &&
          "FIXME: AST inputs not yet supported here!");
   assert(Clang->getFrontendOpts().Inputs[0].getKind().getLanguage() !=
-             InputKind::LLVM_IR &&
+             Language::LLVM_IR &&
          "IR inputs not support here!");
 
   // Configure the various subsystems.
@@ -1624,15 +1625,15 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocationAction(
 
   if (Persistent && !TrackerAct) {
     Clang->getPreprocessor().addPPCallbacks(
-        llvm::make_unique<MacroDefinitionTrackerPPCallbacks>(
+        std::make_unique<MacroDefinitionTrackerPPCallbacks>(
                                            AST->getCurrentTopLevelHashValue()));
     std::vector<std::unique_ptr<ASTConsumer>> Consumers;
     if (Clang->hasASTConsumer())
       Consumers.push_back(Clang->takeASTConsumer());
-    Consumers.push_back(llvm::make_unique<TopLevelDeclTrackerConsumer>(
+    Consumers.push_back(std::make_unique<TopLevelDeclTrackerConsumer>(
         *AST, AST->getCurrentTopLevelHashValue()));
     Clang->setASTConsumer(
-        llvm::make_unique<MultiplexConsumer>(std::move(Consumers)));
+        std::make_unique<MultiplexConsumer>(std::move(Consumers)));
   }
   if (llvm::Error Err = Act->Execute()) {
     consumeError(std::move(Err)); // FIXME this drops errors on the floor.
@@ -1735,6 +1736,7 @@ ASTUnit *ASTUnit::LoadFromCommandLine(
     bool CacheCodeCompletionResults, bool IncludeBriefCommentsInCodeCompletion,
     bool AllowPCHWithCompilerErrors, SkipFunctionBodiesScope SkipFunctionBodies,
     bool SingleFileParse, bool UserFilesAreVolatile, bool ForSerialization,
+    bool RetainExcludedConditionalBlocks,
     llvm::Optional<StringRef> ModuleFormat, std::unique_ptr<ASTUnit> *ErrAST,
     IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) {
   assert(Diags.get() && "no DiagnosticsEngine was provided");
@@ -1762,6 +1764,7 @@ ASTUnit *ASTUnit::LoadFromCommandLine(
   PPOpts.RemappedFilesKeepOriginalName = RemappedFilesKeepOriginalName;
   PPOpts.AllowPCHWithCompilerErrors = AllowPCHWithCompilerErrors;
   PPOpts.SingleFileParseMode = SingleFileParse;
+  PPOpts.RetainExcludedConditionalBlocks = RetainExcludedConditionalBlocks;
 
   // Override the resources path.
   CI->getHeaderSearchOpts().ResourceDir = ResourceFilesPath;
@@ -2211,7 +2214,7 @@ void ASTUnit::CodeComplete(
              InputKind::Source &&
          "FIXME: AST inputs not yet supported here!");
   assert(Clang->getFrontendOpts().Inputs[0].getKind().getLanguage() !=
-             InputKind::LLVM_IR &&
+             Language::LLVM_IR &&
          "IR inputs not support here!");
 
   // Use the source and file managers that we were given.
@@ -2299,26 +2302,19 @@ bool ASTUnit::Save(StringRef File) {
   SmallString<128> TempPath;
   TempPath = File;
   TempPath += "-%%%%%%%%";
-  int fd;
-  if (llvm::sys::fs::createUniqueFile(TempPath, fd, TempPath))
-    return true;
-
   // FIXME: Can we somehow regenerate the stat cache here, or do we need to
   // unconditionally create a stat cache when we parse the file?
-  llvm::raw_fd_ostream Out(fd, /*shouldClose=*/true);
-
-  serialize(Out);
-  Out.close();
-  if (Out.has_error()) {
-    Out.clear_error();
-    return true;
-  }
 
-  if (llvm::sys::fs::rename(TempPath, File)) {
-    llvm::sys::fs::remove(TempPath);
+  if (llvm::Error Err = llvm::writeFileAtomically(
+          TempPath, File, [this](llvm::raw_ostream &Out) {
+            return serialize(Out) ? llvm::make_error<llvm::StringError>(
+                                        "ASTUnit serialization failed",
+                                        llvm::inconvertibleErrorCode())
+                                  : llvm::Error::success();
+          })) {
+    consumeError(std::move(Err));
     return true;
   }
-
   return false;
 }
 
@@ -2369,13 +2365,13 @@ void ASTUnit::TranslateStoredDiagnostics(
     // Rebuild the StoredDiagnostic.
     if (SD.Filename.empty())
       continue;
-    const FileEntry *FE = FileMgr.getFile(SD.Filename);
+    auto FE = FileMgr.getFile(SD.Filename);
     if (!FE)
       continue;
     SourceLocation FileLoc;
     auto ItFileID = PreambleSrcLocCache.find(SD.Filename);
     if (ItFileID == PreambleSrcLocCache.end()) {
-      FileID FID = SrcMgr.translateFile(FE);
+      FileID FID = SrcMgr.translateFile(*FE);
       FileLoc = SrcMgr.getLocForStartOfFile(FID);
       PreambleSrcLocCache[SD.Filename] = FileLoc;
     } else {
@@ -2668,17 +2664,17 @@ bool ASTUnit::isModuleFile() const {
 InputKind ASTUnit::getInputKind() const {
   auto &LangOpts = getLangOpts();
 
-  InputKind::Language Lang;
+  Language Lang;
   if (LangOpts.OpenCL)
-    Lang = InputKind::OpenCL;
+    Lang = Language::OpenCL;
   else if (LangOpts.CUDA)
-    Lang = InputKind::CUDA;
+    Lang = Language::CUDA;
   else if (LangOpts.RenderScript)
-    Lang = InputKind::RenderScript;
+    Lang = Language::RenderScript;
   else if (LangOpts.CPlusPlus)
-    Lang = LangOpts.ObjC ? InputKind::ObjCXX : InputKind::CXX;
+    Lang = LangOpts.ObjC ? Language::ObjCXX : Language::CXX;
   else
-    Lang = LangOpts.ObjC ? InputKind::ObjC : InputKind::C;
+    Lang = LangOpts.ObjC ? Language::ObjC : Language::C;
 
   InputKind::Format Fmt = InputKind::Source;
   if (LangOpts.getCompilingModule() == LangOptions::CMK_ModuleMap)
@@ -2692,20 +2688,20 @@ InputKind ASTUnit::getInputKind() const {
 
 #ifndef NDEBUG
 ASTUnit::ConcurrencyState::ConcurrencyState() {
-  Mutex = new llvm::sys::MutexImpl(/*recursive=*/true);
+  Mutex = new std::recursive_mutex;
 }
 
 ASTUnit::ConcurrencyState::~ConcurrencyState() {
-  delete static_cast<llvm::sys::MutexImpl *>(Mutex);
+  delete static_cast<std::recursive_mutex *>(Mutex);
 }
 
 void ASTUnit::ConcurrencyState::start() {
-  bool acquired = static_cast<llvm::sys::MutexImpl *>(Mutex)->tryacquire();
+  bool acquired = static_cast<std::recursive_mutex *>(Mutex)->try_lock();
   assert(acquired && "Concurrent access to ASTUnit!");
 }
 
 void ASTUnit::ConcurrencyState::finish() {
-  static_cast<llvm::sys::MutexImpl *>(Mutex)->release();
+  static_cast<std::recursive_mutex *>(Mutex)->unlock();
 }
 
 #else // NDEBUG
diff --git a/lib/Frontend/ChainedIncludesSource.cpp b/lib/Frontend/ChainedIncludesSource.cpp
index 48154ecf47423..29fee7246d14c 100644
--- a/lib/Frontend/ChainedIncludesSource.cpp
+++ b/lib/Frontend/ChainedIncludesSource.cpp
@@ -158,7 +158,7 @@ IntrusiveRefCntPtr<ExternalSemaSource> clang::createChainedIncludesSource(
 
     auto Buffer = std::make_shared<PCHBuffer>();
     ArrayRef<std::shared_ptr<ModuleFileExtension>> Extensions;
-    auto consumer = llvm::make_unique<PCHGenerator>(
+    auto consumer = std::make_unique<PCHGenerator>(
         Clang->getPreprocessor(), Clang->getModuleCache(), "-", /*isysroot=*/"",
         Buffer, Extensions, /*AllowASTWithErrors=*/true);
     Clang->getASTContext().setASTMutationListener(
diff --git a/lib/Frontend/CompilerInstance.cpp b/lib/Frontend/CompilerInstance.cpp
index cf0267549e750..c409c07ff133a 100644
--- a/lib/Frontend/CompilerInstance.cpp
+++ b/lib/Frontend/CompilerInstance.cpp
@@ -13,6 +13,7 @@
 #include "clang/Basic/CharInfo.h"
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/FileManager.h"
+#include "clang/Basic/LangStandard.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/Stack.h"
 #include "clang/Basic/TargetInfo.h"
@@ -49,8 +50,6 @@
 #include "llvm/Support/TimeProfiler.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/raw_ostream.h"
-#include <sys/stat.h>
-#include <system_error>
 #include <time.h>
 #include <utility>
 
@@ -85,6 +84,16 @@ void CompilerInstance::setDiagnostics(DiagnosticsEngine *Value) {
   Diagnostics = Value;
 }
 
+void CompilerInstance::setVerboseOutputStream(raw_ostream &Value) {
+  OwnedVerboseOutputStream.release();
+  VerboseOutputStream = &Value;
+}
+
+void CompilerInstance::setVerboseOutputStream(std::unique_ptr<raw_ostream> Value) {
+  OwnedVerboseOutputStream.swap(Value);
+  VerboseOutputStream = OwnedVerboseOutputStream.get();
+}
+
 void CompilerInstance::setTarget(TargetInfo *Value) { Target = Value; }
 void CompilerInstance::setAuxTarget(TargetInfo *Value) { AuxTarget = Value; }
 
@@ -161,7 +170,7 @@ static void collectIncludePCH(CompilerInstance &CI,
 
   StringRef PCHInclude = PPOpts.ImplicitPCHInclude;
   FileManager &FileMgr = CI.getFileManager();
-  const DirectoryEntry *PCHDir = FileMgr.getDirectory(PCHInclude);
+  auto PCHDir = FileMgr.getDirectory(PCHInclude);
   if (!PCHDir) {
     MDC->addFile(PCHInclude);
     return;
@@ -169,7 +178,7 @@ static void collectIncludePCH(CompilerInstance &CI,
 
   std::error_code EC;
   SmallString<128> DirNative;
-  llvm::sys::path::native(PCHDir->getName(), DirNative);
+  llvm::sys::path::native((*PCHDir)->getName(), DirNative);
   llvm::vfs::FileSystem &FS = FileMgr.getVirtualFileSystem();
   SimpleASTReaderListener Validator(CI.getPreprocessor());
   for (llvm::vfs::directory_iterator Dir = FS.dir_begin(DirNative, EC), DirEnd;
@@ -214,9 +223,9 @@ static void SetUpDiagnosticLog(DiagnosticOptions *DiagOpts,
   raw_ostream *OS = &llvm::errs();
   if (DiagOpts->DiagnosticLogFile != "-") {
     // Create the output stream.
-    auto FileOS = llvm::make_unique<llvm::raw_fd_ostream>(
+    auto FileOS = std::make_unique<llvm::raw_fd_ostream>(
         DiagOpts->DiagnosticLogFile, EC,
-        llvm::sys::fs::F_Append | llvm::sys::fs::F_Text);
+        llvm::sys::fs::OF_Append | llvm::sys::fs::OF_Text);
     if (EC) {
       Diags.Report(diag::warn_fe_cc_log_diagnostics_failure)
           << DiagOpts->DiagnosticLogFile << EC.message();
@@ -228,7 +237,7 @@ static void SetUpDiagnosticLog(DiagnosticOptions *DiagOpts,
   }
 
   // Chain in the diagnostic client which will log the diagnostics.
-  auto Logger = llvm::make_unique<LogDiagnosticPrinter>(*OS, DiagOpts,
+  auto Logger = std::make_unique<LogDiagnosticPrinter>(*OS, DiagOpts,
                                                         std::move(StreamOwner));
   if (CodeGenOpts)
     Logger->setDwarfDebugFlags(CodeGenOpts->DwarfDebugFlags);
@@ -342,7 +351,7 @@ static void InitializeFileRemapping(DiagnosticsEngine &Diags,
   // 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);
+    auto ToFile = FileMgr.getFile(RF.second);
     if (!ToFile) {
       Diags.Report(diag::err_fe_remap_missing_to_file) << RF.first << RF.second;
       continue;
@@ -350,7 +359,7 @@ static void InitializeFileRemapping(DiagnosticsEngine &Diags,
 
     // Create the file entry for the file that we're mapping from.
     const FileEntry *FromFile =
-        FileMgr.getVirtualFile(RF.first, ToFile->getSize(), 0);
+        FileMgr.getVirtualFile(RF.first, (*ToFile)->getSize(), 0);
     if (!FromFile) {
       Diags.Report(diag::err_fe_remap_missing_from_file) << RF.first;
       continue;
@@ -358,7 +367,7 @@ static void InitializeFileRemapping(DiagnosticsEngine &Diags,
 
     // Override the contents of the "from" file with the contents of
     // the "to" file.
-    SourceMgr.overrideFileContents(FromFile, ToFile);
+    SourceMgr.overrideFileContents(FromFile, *ToFile);
   }
 
   SourceMgr.setOverridenFilesKeepOriginalName(
@@ -509,7 +518,8 @@ IntrusiveRefCntPtr<ASTReader> CompilerInstance::createPCHExternalASTSource(
       PP, ModuleCache, &Context, PCHContainerRdr, Extensions,
       Sysroot.empty() ? "" : Sysroot.data(), DisablePCHValidation,
       AllowPCHWithCompilerErrors, /*AllowConfigurationMismatch*/ false,
-      HSOpts.ModulesValidateSystemHeaders, UseGlobalModuleIndex));
+      HSOpts.ModulesValidateSystemHeaders, HSOpts.ValidateASTInputFilesContent,
+      UseGlobalModuleIndex));
 
   // We need the external source to be set up before we read the AST, because
   // eagerly-deserialized declarations may use it.
@@ -558,7 +568,7 @@ static bool EnableCodeCompletion(Preprocessor &PP,
                                  unsigned Column) {
   // Tell the source manager to chop off the given file at a specific
   // line and column.
-  const FileEntry *Entry = PP.getFileManager().getFile(Filename);
+  auto Entry = PP.getFileManager().getFile(Filename);
   if (!Entry) {
     PP.getDiagnostics().Report(diag::err_fe_invalid_code_complete_file)
       << Filename;
@@ -566,7 +576,7 @@ static bool EnableCodeCompletion(Preprocessor &PP,
   }
 
   // Truncate the named file at the given line/column.
-  PP.SetCodeCompletionPoint(Entry, Line, Column);
+  PP.SetCodeCompletionPoint(*Entry, Line, Column);
   return false;
 }
 
@@ -666,7 +676,7 @@ CompilerInstance::createDefaultOutputFile(bool Binary, StringRef InFile,
 }
 
 std::unique_ptr<raw_pwrite_stream> CompilerInstance::createNullOutputFile() {
-  return llvm::make_unique<llvm::raw_null_ostream>();
+  return std::make_unique<llvm::raw_null_ostream>();
 }
 
 std::unique_ptr<raw_pwrite_stream>
@@ -775,7 +785,7 @@ std::unique_ptr<llvm::raw_pwrite_stream> CompilerInstance::createOutputFile(
     OSFile = OutFile;
     OS.reset(new llvm::raw_fd_ostream(
         OSFile, Error,
-        (Binary ? llvm::sys::fs::F_None : llvm::sys::fs::F_Text)));
+        (Binary ? llvm::sys::fs::OF_None : llvm::sys::fs::OF_Text)));
     if (Error)
       return nullptr;
   }
@@ -792,7 +802,7 @@ std::unique_ptr<llvm::raw_pwrite_stream> CompilerInstance::createOutputFile(
   if (!Binary || OS->supportsSeeking())
     return std::move(OS);
 
-  auto B = llvm::make_unique<llvm::buffer_ostream>(*OS);
+  auto B = std::make_unique<llvm::buffer_ostream>(*OS);
   assert(!NonSeekStream);
   NonSeekStream = std::move(OS);
   return std::move(B);
@@ -830,32 +840,39 @@ bool CompilerInstance::InitializeSourceManager(
 
   // Figure out where to get and map in the main file.
   if (InputFile != "-") {
-    const FileEntry *File = FileMgr.getFile(InputFile, /*OpenFile=*/true);
-    if (!File) {
+    auto FileOrErr = FileMgr.getFileRef(InputFile, /*OpenFile=*/true);
+    if (!FileOrErr) {
+      // FIXME: include the error in the diagnostic.
+      consumeError(FileOrErr.takeError());
       Diags.Report(diag::err_fe_error_reading) << InputFile;
       return false;
     }
+    FileEntryRef File = *FileOrErr;
 
     // The natural SourceManager infrastructure can't currently handle named
     // pipes, but we would at least like to accept them for the main
     // file. Detect them here, read them with the volatile flag so FileMgr will
     // pick up the correct size, and simply override their contents as we do for
     // STDIN.
-    if (File->isNamedPipe()) {
-      auto MB = FileMgr.getBufferForFile(File, /*isVolatile=*/true);
+    if (File.getFileEntry().isNamedPipe()) {
+      auto MB =
+          FileMgr.getBufferForFile(&File.getFileEntry(), /*isVolatile=*/true);
       if (MB) {
         // Create a new virtual file that will have the correct size.
-        File = FileMgr.getVirtualFile(InputFile, (*MB)->getBufferSize(), 0);
-        SourceMgr.overrideFileContents(File, std::move(*MB));
+        const FileEntry *FE =
+            FileMgr.getVirtualFile(InputFile, (*MB)->getBufferSize(), 0);
+        SourceMgr.overrideFileContents(FE, std::move(*MB));
+        SourceMgr.setMainFileID(
+            SourceMgr.createFileID(FE, SourceLocation(), Kind));
       } else {
         Diags.Report(diag::err_cannot_open_file) << InputFile
                                                  << MB.getError().message();
         return false;
       }
+    } else {
+      SourceMgr.setMainFileID(
+          SourceMgr.createFileID(File, SourceLocation(), Kind));
     }
-
-    SourceMgr.setMainFileID(
-        SourceMgr.createFileID(File, SourceLocation(), Kind));
   } else {
     llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> SBOrErr =
         llvm::MemoryBuffer::getSTDIN();
@@ -884,9 +901,12 @@ bool CompilerInstance::ExecuteAction(FrontendAction &Act) {
   assert(!getFrontendOpts().ShowHelp && "Client must handle '-help'!");
   assert(!getFrontendOpts().ShowVersion && "Client must handle '-version'!");
 
-  // FIXME: Take this as an argument, once all the APIs we used have moved to
-  // taking it as an input instead of hard-coding llvm::errs.
-  raw_ostream &OS = llvm::errs();
+  // Mark this point as the bottom of the stack if we don't have somewhere
+  // better. We generally expect frontend actions to be invoked with (nearly)
+  // DesiredStackSpace available.
+  noteBottomOfStack();
+
+  raw_ostream &OS = getVerboseOutputStream();
 
   if (!Act.PrepareToExecute(*this))
     return false;
@@ -986,8 +1006,8 @@ bool CompilerInstance::ExecuteAction(FrontendAction &Act) {
   StringRef StatsFile = getFrontendOpts().StatsFile;
   if (!StatsFile.empty()) {
     std::error_code EC;
-    auto StatS = llvm::make_unique<llvm::raw_fd_ostream>(StatsFile, EC,
-                                                         llvm::sys::fs::F_Text);
+    auto StatS = std::make_unique<llvm::raw_fd_ostream>(
+        StatsFile, EC, llvm::sys::fs::OF_Text);
     if (EC) {
       getDiagnostics().Report(diag::warn_fe_unable_to_open_stats_file)
           << StatsFile << EC.message();
@@ -1001,14 +1021,14 @@ bool CompilerInstance::ExecuteAction(FrontendAction &Act) {
 
 /// Determine the appropriate source input kind based on language
 /// options.
-static InputKind::Language getLanguageFromOptions(const LangOptions &LangOpts) {
+static Language getLanguageFromOptions(const LangOptions &LangOpts) {
   if (LangOpts.OpenCL)
-    return InputKind::OpenCL;
+    return Language::OpenCL;
   if (LangOpts.CUDA)
-    return InputKind::CUDA;
+    return Language::CUDA;
   if (LangOpts.ObjC)
-    return LangOpts.CPlusPlus ? InputKind::ObjCXX : InputKind::ObjC;
-  return LangOpts.CPlusPlus ? InputKind::CXX : InputKind::C;
+    return LangOpts.CPlusPlus ? Language::ObjCXX : Language::ObjC;
+  return LangOpts.CPlusPlus ? Language::CXX : Language::C;
 }
 
 /// Compile a module file for the given module, using the options
@@ -1154,7 +1174,9 @@ static const FileEntry *getPublicModuleMap(const FileEntry *File,
     llvm::sys::path::append(PublicFilename, "module.modulemap");
   else
     return nullptr;
-  return FileMgr.getFile(PublicFilename);
+  if (auto FE = FileMgr.getFile(PublicFilename))
+    return *FE;
+  return nullptr;
 }
 
 /// Compile a module file for the given module, using the options
@@ -1367,22 +1389,22 @@ static void checkConfigMacro(Preprocessor &PP, StringRef ConfigMacro,
 /// Write a new timestamp file with the given path.
 static void writeTimestampFile(StringRef TimestampFile) {
   std::error_code EC;
-  llvm::raw_fd_ostream Out(TimestampFile.str(), EC, llvm::sys::fs::F_None);
+  llvm::raw_fd_ostream Out(TimestampFile.str(), EC, llvm::sys::fs::OF_None);
 }
 
 /// Prune the module cache of modules that haven't been accessed in
 /// a long time.
 static void pruneModuleCache(const HeaderSearchOptions &HSOpts) {
-  struct stat StatBuf;
+  llvm::sys::fs::file_status StatBuf;
   llvm::SmallString<128> TimestampFile;
   TimestampFile = HSOpts.ModuleCachePath;
   assert(!TimestampFile.empty());
   llvm::sys::path::append(TimestampFile, "modules.timestamp");
 
   // Try to stat() the timestamp file.
-  if (::stat(TimestampFile.c_str(), &StatBuf)) {
+  if (std::error_code EC = llvm::sys::fs::status(TimestampFile, StatBuf)) {
     // If the timestamp file wasn't there, create one now.
-    if (errno == ENOENT) {
+    if (EC == std::errc::no_such_file_or_directory) {
       writeTimestampFile(TimestampFile);
     }
     return;
@@ -1390,7 +1412,8 @@ 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 TimeStampModTime =
+      llvm::sys::toTimeT(StatBuf.getLastModificationTime());
   time_t CurrentTime = time(nullptr);
   if (CurrentTime - TimeStampModTime <= time_t(HSOpts.ModuleCachePruneInterval))
     return;
@@ -1422,11 +1445,11 @@ static void pruneModuleCache(const HeaderSearchOptions &HSOpts) {
 
       // Look at this file. If we can't stat it, there's nothing interesting
       // there.
-      if (::stat(File->path().c_str(), &StatBuf))
+      if (llvm::sys::fs::status(File->path(), StatBuf))
         continue;
 
       // If the file has been used recently enough, leave it there.
-      time_t FileAccessTime = StatBuf.st_atime;
+      time_t FileAccessTime = llvm::sys::toTimeT(StatBuf.getLastAccessedTime());
       if (CurrentTime - FileAccessTime <=
               time_t(HSOpts.ModuleCachePruneAfter)) {
         continue;
@@ -1467,7 +1490,7 @@ void CompilerInstance::createModuleManager() {
     const PreprocessorOptions &PPOpts = getPreprocessorOpts();
     std::unique_ptr<llvm::Timer> ReadTimer;
     if (FrontendTimerGroup)
-      ReadTimer = llvm::make_unique<llvm::Timer>("reading_modules",
+      ReadTimer = std::make_unique<llvm::Timer>("reading_modules",
                                                  "Reading modules",
                                                  *FrontendTimerGroup);
     ModuleManager = new ASTReader(
@@ -1477,6 +1500,7 @@ void CompilerInstance::createModuleManager() {
         /*AllowASTWithCompilerErrors=*/false,
         /*AllowConfigurationMismatch=*/false,
         HSOpts.ModulesValidateSystemHeaders,
+        HSOpts.ValidateASTInputFilesContent,
         getFrontendOpts().UseGlobalModuleIndex, std::move(ReadTimer));
     if (hasASTConsumer()) {
       ModuleManager->setDeserializationListener(
@@ -1562,7 +1586,7 @@ bool CompilerInstance::loadModuleFile(StringRef FileName) {
                                           SourceLocation())
         <= DiagnosticsEngine::Warning;
 
-  auto Listener = llvm::make_unique<ReadModuleNames>(*this);
+  auto Listener = std::make_unique<ReadModuleNames>(*this);
   auto &ListenerRef = *Listener;
   ASTReader::ListenerScope ReadModuleNamesListener(*ModuleManager,
                                                    std::move(Listener));
@@ -1718,8 +1742,9 @@ CompilerInstance::loadModule(SourceLocation ImportLoc,
       if (Source != ModuleCache && !Module) {
         Module = PP->getHeaderSearchInfo().lookupModule(ModuleName, true,
                                                         !IsInclusionDirective);
+        auto ModuleFile = FileMgr->getFile(ModuleFileName);
         if (!Module || !Module->getASTFile() ||
-            FileMgr->getFile(ModuleFileName) != Module->getASTFile()) {
+            !ModuleFile || (*ModuleFile != Module->getASTFile())) {
           // Error out if Module does not refer to the file in the prebuilt
           // module path.
           getDiagnostics().Report(ModuleNameLoc, diag::err_module_prebuilt)
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 8a9844096f081..665695ec3b18f 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -18,6 +18,7 @@
 #include "clang/Basic/FileSystemOptions.h"
 #include "clang/Basic/LLVM.h"
 #include "clang/Basic/LangOptions.h"
+#include "clang/Basic/LangStandard.h"
 #include "clang/Basic/ObjCRuntime.h"
 #include "clang/Basic/Sanitizers.h"
 #include "clang/Basic/SourceLocation.h"
@@ -34,7 +35,6 @@
 #include "clang/Frontend/FrontendDiagnostic.h"
 #include "clang/Frontend/FrontendOptions.h"
 #include "clang/Frontend/FrontendPluginRegistry.h"
-#include "clang/Frontend/LangStandard.h"
 #include "clang/Frontend/MigratorOptions.h"
 #include "clang/Frontend/PreprocessorOutputOptions.h"
 #include "clang/Frontend/Utils.h"
@@ -122,7 +122,7 @@ CompilerInvocationBase::~CompilerInvocationBase() = default;
 static unsigned getOptimizationLevel(ArgList &Args, InputKind IK,
                                      DiagnosticsEngine &Diags) {
   unsigned DefaultOpt = llvm::CodeGenOpt::None;
-  if (IK.getLanguage() == InputKind::OpenCL && !Args.hasArg(OPT_cl_opt_disable))
+  if (IK.getLanguage() == Language::OpenCL && !Args.hasArg(OPT_cl_opt_disable))
     DefaultOpt = llvm::CodeGenOpt::Default;
 
   if (Arg *A = Args.getLastArg(options::OPT_O_Group)) {
@@ -303,7 +303,7 @@ static bool ParseAnalyzerArgs(AnalyzerOptions &Opts, ArgList &Args,
         .Case("true", true)
         .Case("false", false)
         .Default(false);
-  Opts.DisableAllChecks = Args.hasArg(OPT_analyzer_disable_all_checks);
+  Opts.DisableAllCheckers = Args.hasArg(OPT_analyzer_disable_all_checks);
 
   Opts.visualizeExplodedGraphWithGraphViz =
     Args.hasArg(OPT_analyzer_viz_egraph_graphviz);
@@ -324,18 +324,18 @@ static bool ParseAnalyzerArgs(AnalyzerOptions &Opts, ArgList &Args,
       getLastArgIntValue(Args, OPT_analyzer_inline_max_stack_depth,
                          Opts.InlineMaxStackDepth, Diags);
 
-  Opts.CheckersControlList.clear();
+  Opts.CheckersAndPackages.clear();
   for (const Arg *A :
        Args.filtered(OPT_analyzer_checker, OPT_analyzer_disable_checker)) {
     A->claim();
-    bool enable = (A->getOption().getID() == OPT_analyzer_checker);
+    bool IsEnabled = A->getOption().getID() == OPT_analyzer_checker;
     // We can have a list of comma separated checker names, e.g:
     // '-analyzer-checker=cocoa,unix'
-    StringRef checkerList = A->getValue();
-    SmallVector<StringRef, 4> checkers;
-    checkerList.split(checkers, ",");
-    for (auto checker : checkers)
-      Opts.CheckersControlList.emplace_back(checker, enable);
+    StringRef CheckerAndPackageList = A->getValue();
+    SmallVector<StringRef, 16> CheckersAndPackages;
+    CheckerAndPackageList.split(CheckersAndPackages, ",");
+    for (const StringRef CheckerOrPackage : CheckersAndPackages)
+      Opts.CheckersAndPackages.emplace_back(CheckerOrPackage, IsEnabled);
   }
 
   // Go through the analyzer configuration options.
@@ -464,6 +464,35 @@ static void parseAnalyzerConfigs(AnalyzerOptions &AnOpts,
 
   // At this point, AnalyzerOptions is configured. Let's validate some options.
 
+  // FIXME: Here we try to validate the silenced checkers or packages are valid.
+  // The current approach only validates the registered checkers which does not
+  // contain the runtime enabled checkers and optimally we would validate both.
+  if (!AnOpts.RawSilencedCheckersAndPackages.empty()) {
+    std::vector<StringRef> Checkers =
+        AnOpts.getRegisteredCheckers(/*IncludeExperimental=*/true);
+    std::vector<StringRef> Packages =
+        AnOpts.getRegisteredPackages(/*IncludeExperimental=*/true);
+
+    SmallVector<StringRef, 16> CheckersAndPackages;
+    AnOpts.RawSilencedCheckersAndPackages.split(CheckersAndPackages, ";");
+
+    for (const StringRef CheckerOrPackage : CheckersAndPackages) {
+      if (Diags) {
+        bool IsChecker = CheckerOrPackage.contains('.');
+        bool IsValidName =
+            IsChecker
+                ? llvm::find(Checkers, CheckerOrPackage) != Checkers.end()
+                : llvm::find(Packages, CheckerOrPackage) != Packages.end();
+
+        if (!IsValidName)
+          Diags->Report(diag::err_unknown_analyzer_checker_or_package)
+              << CheckerOrPackage;
+      }
+
+      AnOpts.SilencedCheckersAndPackages.emplace_back(CheckerOrPackage);
+    }
+  }
+
   if (!Diags)
     return;
 
@@ -729,6 +758,8 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.CodeViewGHash = Args.hasArg(OPT_gcodeview_ghash);
   Opts.MacroDebugInfo = Args.hasArg(OPT_debug_info_macro);
   Opts.WholeProgramVTables = Args.hasArg(OPT_fwhole_program_vtables);
+  Opts.VirtualFunctionElimination =
+      Args.hasArg(OPT_fvirtual_function_elimination);
   Opts.LTOVisibilityPublicStd = Args.hasArg(OPT_flto_visibility_public_std);
   Opts.SplitDwarfFile = Args.getLastArgValue(OPT_split_dwarf_file);
   Opts.SplitDwarfOutput = Args.getLastArgValue(OPT_split_dwarf_output);
@@ -748,10 +779,14 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.DisableLLVMPasses = Args.hasArg(OPT_disable_llvm_passes);
   Opts.DisableLifetimeMarkers = Args.hasArg(OPT_disable_lifetimemarkers);
 
+  const llvm::Triple::ArchType DebugEntryValueArchs[] = {
+      llvm::Triple::x86, llvm::Triple::x86_64, llvm::Triple::aarch64,
+      llvm::Triple::arm, llvm::Triple::armeb};
+
   llvm::Triple T(TargetOpts.Triple);
-  llvm::Triple::ArchType Arch = T.getArch();
   if (Opts.OptimizationLevel > 0 &&
-      (Arch == llvm::Triple::x86 || Arch == llvm::Triple::x86_64))
+      Opts.getDebugInfo() >= codegenoptions::LimitedDebugInfo &&
+      llvm::is_contained(DebugEntryValueArchs, T.getArch()))
     Opts.EnableDebugEntryValues = Args.hasArg(OPT_femit_debug_entry_values);
 
   Opts.DisableO0ImplyOptNone = Args.hasArg(OPT_disable_O0_optnone);
@@ -823,8 +858,32 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.CXXCtorDtorAliases = Args.hasArg(OPT_mconstructor_aliases);
   Opts.CodeModel = TargetOpts.CodeModel;
   Opts.DebugPass = Args.getLastArgValue(OPT_mdebug_pass);
-  Opts.DisableFPElim =
-      (Args.hasArg(OPT_mdisable_fp_elim) || Args.hasArg(OPT_pg));
+
+  // Handle -mframe-pointer option.
+  if (Arg *A = Args.getLastArg(OPT_mframe_pointer_EQ)) {
+    CodeGenOptions::FramePointerKind FP;
+    StringRef Name = A->getValue();
+    bool ValidFP = true;
+    if (Name == "none")
+      FP = CodeGenOptions::FramePointerKind::None;
+    else if (Name == "non-leaf")
+      FP = CodeGenOptions::FramePointerKind::NonLeaf;
+    else if (Name == "all")
+      FP = CodeGenOptions::FramePointerKind::All;
+    else {
+      Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) << Name;
+      Success = false;
+      ValidFP = false;
+    }
+    if (ValidFP)
+      Opts.setFramePointer(FP);
+  }
+
+  // -pg may override -mframe-pointer
+  // TODO: This should be merged into getFramePointerKind in Clang.cpp.
+  if (Args.hasArg(OPT_pg))
+    Opts.setFramePointer(CodeGenOptions::FramePointerKind::All);
+
   Opts.DisableFree = Args.hasArg(OPT_disable_free);
   Opts.DiscardValueNames = Args.hasArg(OPT_discard_value_names);
   Opts.DisableTailCalls = Args.hasArg(OPT_mdisable_tail_calls);
@@ -864,6 +923,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.NumRegisterParameters = getLastArgIntValue(Args, OPT_mregparm, 0, Diags);
   Opts.NoExecStack = Args.hasArg(OPT_mno_exec_stack);
   Opts.FatalWarnings = Args.hasArg(OPT_massembler_fatal_warnings);
+  Opts.NoWarn = Args.hasArg(OPT_massembler_no_warn);
   Opts.EnableSegmentedStacks = Args.hasArg(OPT_split_stacks);
   Opts.RelaxAll = Args.hasArg(OPT_mrelax_all);
   Opts.IncrementalLinkerCompatible =
@@ -871,7 +931,6 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.PIECopyRelocations =
       Args.hasArg(OPT_mpie_copy_relocations);
   Opts.NoPLT = Args.hasArg(OPT_fno_plt);
-  Opts.OmitLeafFramePointer = Args.hasArg(OPT_momit_leaf_frame_pointer);
   Opts.SaveTempLabels = Args.hasArg(OPT_msave_temp_labels);
   Opts.NoDwarfDirectoryAsm = Args.hasArg(OPT_fno_dwarf_directory_asm);
   Opts.SoftFloat = Args.hasArg(OPT_msoft_float);
@@ -921,7 +980,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.LTOUnit = Args.hasFlag(OPT_flto_unit, OPT_fno_lto_unit, false);
   Opts.EnableSplitLTOUnit = Args.hasArg(OPT_fsplit_lto_unit);
   if (Arg *A = Args.getLastArg(OPT_fthinlto_index_EQ)) {
-    if (IK.getLanguage() != InputKind::LLVM_IR)
+    if (IK.getLanguage() != Language::LLVM_IR)
       Diags.Report(diag::err_drv_argument_only_allowed_with)
           << A->getAsString(Args) << "-x ir";
     Opts.ThinLTOIndexFile = Args.getLastArgValue(OPT_fthinlto_index_EQ);
@@ -1115,6 +1174,8 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.SanitizeCfiCrossDso = Args.hasArg(OPT_fsanitize_cfi_cross_dso);
   Opts.SanitizeCfiICallGeneralizePointers =
       Args.hasArg(OPT_fsanitize_cfi_icall_generalize_pointers);
+  Opts.SanitizeCfiCanonicalJumpTables =
+      Args.hasArg(OPT_fsanitize_cfi_canonical_jump_tables);
   Opts.SanitizeStats = Args.hasArg(OPT_fsanitize_stats);
   if (Arg *A = Args.getLastArg(
           OPT_fsanitize_address_poison_custom_array_cookie,
@@ -1262,7 +1323,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
 
   if (Opts.DiagnosticsWithHotness && !UsingProfile &&
       // An IR file will contain PGO as metadata
-      IK.getLanguage() != InputKind::LLVM_IR)
+      IK.getLanguage() != Language::LLVM_IR)
     Diags.Report(diag::warn_drv_diagnostics_hotness_requires_pgo)
         << "-fdiagnostics-show-hotness";
 
@@ -1675,23 +1736,30 @@ static InputKind ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
       Opts.ProgramAction = frontend::GenerateHeaderModule; break;
     case OPT_emit_pch:
       Opts.ProgramAction = frontend::GeneratePCH; break;
-    case OPT_emit_iterface_stubs: {
-      llvm::Optional<frontend::ActionKind> ProgramAction =
-          llvm::StringSwitch<llvm::Optional<frontend::ActionKind>>(
-              Args.hasArg(OPT_iterface_stub_version_EQ)
-                  ? Args.getLastArgValue(OPT_iterface_stub_version_EQ)
-                  : "")
-              .Case("experimental-yaml-elf-v1",
-                    frontend::GenerateInterfaceYAMLExpV1)
-              .Case("experimental-tapi-elf-v1",
-                    frontend::GenerateInterfaceTBEExpV1)
-              .Default(llvm::None);
-      if (!ProgramAction)
+    case OPT_emit_interface_stubs: {
+      StringRef ArgStr =
+          Args.hasArg(OPT_interface_stub_version_EQ)
+              ? Args.getLastArgValue(OPT_interface_stub_version_EQ)
+              : "experimental-ifs-v1";
+      if (ArgStr == "experimental-yaml-elf-v1" ||
+          ArgStr == "experimental-tapi-elf-v1") {
+        std::string ErrorMessage =
+            "Invalid interface stub format: " + ArgStr.str() +
+            " is deprecated.";
+        Diags.Report(diag::err_drv_invalid_value)
+            << "Must specify a valid interface stub format type, ie: "
+               "-interface-stub-version=experimental-ifs-v1"
+            << ErrorMessage;
+      } else if (ArgStr != "experimental-ifs-v1") {
+        std::string ErrorMessage =
+            "Invalid interface stub format: " + ArgStr.str() + ".";
         Diags.Report(diag::err_drv_invalid_value)
-            << "Must specify a valid interface stub format type using "
-            << "-interface-stub-version=<experimental-tapi-elf-v1 | "
-               "experimental-yaml-elf-v1>";
-      Opts.ProgramAction = *ProgramAction;
+            << "Must specify a valid interface stub format type, ie: "
+               "-interface-stub-version=experimental-ifs-v1"
+            << ErrorMessage;
+      } else {
+        Opts.ProgramAction = frontend::GenerateInterfaceIfsExpV1;
+      }
       break;
     }
     case OPT_init_only:
@@ -1773,6 +1841,8 @@ static InputKind ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
   Opts.ShowTimers = Args.hasArg(OPT_ftime_report);
   Opts.PrintSupportedCPUs = Args.hasArg(OPT_print_supported_cpus);
   Opts.TimeTrace = Args.hasArg(OPT_ftime_trace);
+  Opts.TimeTraceGranularity = getLastArgIntValue(
+      Args, OPT_ftime_trace_granularity_EQ, Opts.TimeTraceGranularity, Diags);
   Opts.ShowVersion = Args.hasArg(OPT_version);
   Opts.ASTMergeFiles = Args.getAllArgValues(OPT_ast_merge);
   Opts.LLVMArgs = Args.getAllArgValues(OPT_mllvm);
@@ -1877,7 +1947,7 @@ static InputKind ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
       << "ARC migration" << "ObjC migration";
   }
 
-  InputKind DashX(InputKind::Unknown);
+  InputKind DashX(Language::Unknown);
   if (const Arg *A = Args.getLastArg(OPT_x)) {
     StringRef XValue = A->getValue();
 
@@ -1890,33 +1960,33 @@ static InputKind ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
 
     // Principal languages.
     DashX = llvm::StringSwitch<InputKind>(XValue)
-                .Case("c", InputKind::C)
-                .Case("cl", InputKind::OpenCL)
-                .Case("cuda", InputKind::CUDA)
-                .Case("hip", InputKind::HIP)
-                .Case("c++", InputKind::CXX)
-                .Case("objective-c", InputKind::ObjC)
-                .Case("objective-c++", InputKind::ObjCXX)
-                .Case("renderscript", InputKind::RenderScript)
-                .Default(InputKind::Unknown);
+                .Case("c", Language::C)
+                .Case("cl", Language::OpenCL)
+                .Case("cuda", Language::CUDA)
+                .Case("hip", Language::HIP)
+                .Case("c++", Language::CXX)
+                .Case("objective-c", Language::ObjC)
+                .Case("objective-c++", Language::ObjCXX)
+                .Case("renderscript", Language::RenderScript)
+                .Default(Language::Unknown);
 
     // "objc[++]-cpp-output" is an acceptable synonym for
     // "objective-c[++]-cpp-output".
     if (DashX.isUnknown() && Preprocessed && !IsHeaderFile && !ModuleMap)
       DashX = llvm::StringSwitch<InputKind>(XValue)
-                  .Case("objc", InputKind::ObjC)
-                  .Case("objc++", InputKind::ObjCXX)
-                  .Default(InputKind::Unknown);
+                  .Case("objc", Language::ObjC)
+                  .Case("objc++", Language::ObjCXX)
+                  .Default(Language::Unknown);
 
     // Some special cases cannot be combined with suffixes.
     if (DashX.isUnknown() && !Preprocessed && !ModuleMap && !IsHeaderFile)
       DashX = llvm::StringSwitch<InputKind>(XValue)
-                  .Case("cpp-output", InputKind(InputKind::C).getPreprocessed())
-                  .Case("assembler-with-cpp", InputKind::Asm)
+                  .Case("cpp-output", InputKind(Language::C).getPreprocessed())
+                  .Case("assembler-with-cpp", Language::Asm)
                   .Cases("ast", "pcm",
-                         InputKind(InputKind::Unknown, InputKind::Precompiled))
-                  .Case("ir", InputKind::LLVM_IR)
-                  .Default(InputKind::Unknown);
+                         InputKind(Language::Unknown, InputKind::Precompiled))
+                  .Case("ir", Language::LLVM_IR)
+                  .Default(Language::Unknown);
 
     if (DashX.isUnknown())
       Diags.Report(diag::err_drv_invalid_value)
@@ -1940,7 +2010,7 @@ static InputKind ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
         StringRef(Inputs[i]).rsplit('.').second);
       // FIXME: Warn on this?
       if (IK.isUnknown())
-        IK = InputKind::C;
+        IK = Language::C;
       // FIXME: Remove this hack.
       if (i == 0)
         DashX = IK;
@@ -1997,6 +2067,7 @@ static void ParseHeaderSearchArgs(HeaderSearchOptions &Opts, ArgList &Args,
     Opts.AddPrebuiltModulePath(A->getValue());
   Opts.DisableModuleHash = Args.hasArg(OPT_fdisable_module_hash);
   Opts.ModulesHashContent = Args.hasArg(OPT_fmodules_hash_content);
+  Opts.ModulesStrictContextHash = Args.hasArg(OPT_fmodules_strict_context_hash);
   Opts.ModulesValidateDiagnosticOptions =
       !Args.hasArg(OPT_fmodules_disable_diagnostic_validation);
   Opts.ImplicitModuleMaps = Args.hasArg(OPT_fimplicit_module_maps);
@@ -2011,6 +2082,8 @@ static void ParseHeaderSearchArgs(HeaderSearchOptions &Opts, ArgList &Args,
       getLastArgUInt64Value(Args, OPT_fbuild_session_timestamp, 0);
   Opts.ModulesValidateSystemHeaders =
       Args.hasArg(OPT_fmodules_validate_system_headers);
+  Opts.ValidateASTInputFilesContent =
+      Args.hasArg(OPT_fvalidate_ast_input_files_content);
   if (const Arg *A = Args.getLastArg(OPT_fmodule_format_EQ))
     Opts.ModuleFormat = A->getValue();
 
@@ -2114,7 +2187,7 @@ void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK,
   // FIXME: Perhaps a better model would be for a single source file to have
   // multiple language standards (C / C++ std, ObjC std, OpenCL std, OpenMP std)
   // simultaneously active?
-  if (IK.getLanguage() == InputKind::Asm) {
+  if (IK.getLanguage() == Language::Asm) {
     Opts.AsmPreprocessor = 1;
   } else if (IK.isObjectiveC()) {
     Opts.ObjC = 1;
@@ -2123,17 +2196,17 @@ void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK,
   if (LangStd == LangStandard::lang_unspecified) {
     // Based on the base language, pick one.
     switch (IK.getLanguage()) {
-    case InputKind::Unknown:
-    case InputKind::LLVM_IR:
+    case Language::Unknown:
+    case Language::LLVM_IR:
       llvm_unreachable("Invalid input kind!");
-    case InputKind::OpenCL:
+    case Language::OpenCL:
       LangStd = LangStandard::lang_opencl10;
       break;
-    case InputKind::CUDA:
+    case Language::CUDA:
       LangStd = LangStandard::lang_cuda;
       break;
-    case InputKind::Asm:
-    case InputKind::C:
+    case Language::Asm:
+    case Language::C:
 #if defined(CLANG_DEFAULT_STD_C)
       LangStd = CLANG_DEFAULT_STD_C;
 #else
@@ -2144,25 +2217,25 @@ void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK,
         LangStd = LangStandard::lang_gnu11;
 #endif
       break;
-    case InputKind::ObjC:
+    case Language::ObjC:
 #if defined(CLANG_DEFAULT_STD_C)
       LangStd = CLANG_DEFAULT_STD_C;
 #else
       LangStd = LangStandard::lang_gnu11;
 #endif
       break;
-    case InputKind::CXX:
-    case InputKind::ObjCXX:
+    case Language::CXX:
+    case Language::ObjCXX:
 #if defined(CLANG_DEFAULT_STD_CXX)
       LangStd = CLANG_DEFAULT_STD_CXX;
 #else
       LangStd = LangStandard::lang_gnucxx14;
 #endif
       break;
-    case InputKind::RenderScript:
+    case Language::RenderScript:
       LangStd = LangStandard::lang_c99;
       break;
-    case InputKind::HIP:
+    case Language::HIP:
       LangStd = LangStandard::lang_hip;
       break;
     }
@@ -2182,6 +2255,7 @@ void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK,
   Opts.Digraphs = Std.hasDigraphs();
   Opts.GNUMode = Std.isGNUMode();
   Opts.GNUInline = !Opts.C99 && !Opts.CPlusPlus;
+  Opts.GNUCVersion = 0;
   Opts.HexFloats = Std.hasHexFloats();
   Opts.ImplicitInt = Std.hasImplicitInt();
 
@@ -2202,7 +2276,7 @@ void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK,
   if (Opts.OpenCL) {
     Opts.AltiVec = 0;
     Opts.ZVector = 0;
-    Opts.LaxVectorConversions = 0;
+    Opts.setLaxVectorConversions(LangOptions::LaxVectorConversionKind::None);
     Opts.setDefaultFPContractMode(LangOptions::FPC_On);
     Opts.NativeHalfType = 1;
     Opts.NativeHalfArgsAndReturns = 1;
@@ -2219,13 +2293,13 @@ void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK,
     }
   }
 
-  Opts.HIP = IK.getLanguage() == InputKind::HIP;
-  Opts.CUDA = IK.getLanguage() == InputKind::CUDA || Opts.HIP;
+  Opts.HIP = IK.getLanguage() == Language::HIP;
+  Opts.CUDA = IK.getLanguage() == Language::CUDA || Opts.HIP;
   if (Opts.CUDA)
     // Set default FP_CONTRACT to FAST.
     Opts.setDefaultFPContractMode(LangOptions::FPC_Fast);
 
-  Opts.RenderScript = IK.getLanguage() == InputKind::RenderScript;
+  Opts.RenderScript = IK.getLanguage() == Language::RenderScript;
   if (Opts.RenderScript) {
     Opts.NativeHalfType = 1;
     Opts.NativeHalfArgsAndReturns = 1;
@@ -2273,32 +2347,31 @@ static Visibility parseVisibility(Arg *arg, ArgList &args,
 static bool IsInputCompatibleWithStandard(InputKind IK,
                                           const LangStandard &S) {
   switch (IK.getLanguage()) {
-  case InputKind::Unknown:
-  case InputKind::LLVM_IR:
+  case Language::Unknown:
+  case Language::LLVM_IR:
     llvm_unreachable("should not parse language flags for this input");
 
-  case InputKind::C:
-  case InputKind::ObjC:
-  case InputKind::RenderScript:
-    return S.getLanguage() == InputKind::C;
+  case Language::C:
+  case Language::ObjC:
+  case Language::RenderScript:
+    return S.getLanguage() == Language::C;
 
-  case InputKind::OpenCL:
-    return S.getLanguage() == InputKind::OpenCL;
+  case Language::OpenCL:
+    return S.getLanguage() == Language::OpenCL;
 
-  case InputKind::CXX:
-  case InputKind::ObjCXX:
-    return S.getLanguage() == InputKind::CXX;
+  case Language::CXX:
+  case Language::ObjCXX:
+    return S.getLanguage() == Language::CXX;
 
-  case InputKind::CUDA:
+  case Language::CUDA:
     // FIXME: What -std= values should be permitted for CUDA compilations?
-    return S.getLanguage() == InputKind::CUDA ||
-           S.getLanguage() == InputKind::CXX;
+    return S.getLanguage() == Language::CUDA ||
+           S.getLanguage() == Language::CXX;
 
-  case InputKind::HIP:
-    return S.getLanguage() == InputKind::CXX ||
-           S.getLanguage() == InputKind::HIP;
+  case Language::HIP:
+    return S.getLanguage() == Language::CXX || S.getLanguage() == Language::HIP;
 
-  case InputKind::Asm:
+  case Language::Asm:
     // Accept (and ignore) all -std= values.
     // FIXME: The -std= value is not ignored; it affects the tokenization
     // and preprocessing rules if we're preprocessing this asm input.
@@ -2311,29 +2384,29 @@ static bool IsInputCompatibleWithStandard(InputKind IK,
 /// Get language name for given input kind.
 static const StringRef GetInputKindName(InputKind IK) {
   switch (IK.getLanguage()) {
-  case InputKind::C:
+  case Language::C:
     return "C";
-  case InputKind::ObjC:
+  case Language::ObjC:
     return "Objective-C";
-  case InputKind::CXX:
+  case Language::CXX:
     return "C++";
-  case InputKind::ObjCXX:
+  case Language::ObjCXX:
     return "Objective-C++";
-  case InputKind::OpenCL:
+  case Language::OpenCL:
     return "OpenCL";
-  case InputKind::CUDA:
+  case Language::CUDA:
     return "CUDA";
-  case InputKind::RenderScript:
+  case Language::RenderScript:
     return "RenderScript";
-  case InputKind::HIP:
+  case Language::HIP:
     return "HIP";
 
-  case InputKind::Asm:
+  case Language::Asm:
     return "Asm";
-  case InputKind::LLVM_IR:
+  case Language::LLVM_IR:
     return "LLVM IR";
 
-  case InputKind::Unknown:
+  case Language::Unknown:
     break;
   }
   llvm_unreachable("unknown input language");
@@ -2346,13 +2419,7 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
   // FIXME: Cleanup per-file based stuff.
   LangStandard::Kind LangStd = LangStandard::lang_unspecified;
   if (const Arg *A = Args.getLastArg(OPT_std_EQ)) {
-    LangStd = llvm::StringSwitch<LangStandard::Kind>(A->getValue())
-#define LANGSTANDARD(id, name, lang, desc, features) \
-      .Case(name, LangStandard::lang_##id)
-#define LANGSTANDARD_ALIAS(id, alias) \
-      .Case(alias, LangStandard::lang_##id)
-#include "clang/Frontend/LangStandards.def"
-      .Default(LangStandard::lang_unspecified);
+    LangStd = LangStandard::getLangKind(A->getValue());
     if (LangStd == LangStandard::lang_unspecified) {
       Diags.Report(diag::err_drv_invalid_value)
         << A->getAsString(Args) << A->getValue();
@@ -2370,13 +2437,13 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
 #define LANGSTANDARD_ALIAS(id, alias) \
           if (KindValue == LangStandard::lang_##id) ++NumAliases;
 #define LANGSTANDARD_ALIAS_DEPR(id, alias)
-#include "clang/Frontend/LangStandards.def"
+#include "clang/Basic/LangStandards.def"
           Diag << NumAliases;
 #define LANGSTANDARD(id, name, lang, desc, features)
 #define LANGSTANDARD_ALIAS(id, alias) \
           if (KindValue == LangStandard::lang_##id) Diag << alias;
 #define LANGSTANDARD_ALIAS_DEPR(id, alias)
-#include "clang/Frontend/LangStandards.def"
+#include "clang/Basic/LangStandards.def"
         }
       }
     } else {
@@ -2408,7 +2475,7 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
         .Cases("cl1.1", "CL1.1", LangStandard::lang_opencl11)
         .Cases("cl1.2", "CL1.2", LangStandard::lang_opencl12)
         .Cases("cl2.0", "CL2.0", LangStandard::lang_opencl20)
-        .Case("c++", LangStandard::lang_openclcpp)
+        .Cases("clc++", "CLC++", LangStandard::lang_openclcpp)
         .Default(LangStandard::lang_unspecified);
 
     if (OpenCLLangStd == LangStandard::lang_unspecified) {
@@ -2461,6 +2528,7 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
     Opts.CUDADeviceApproxTranscendentals = 1;
 
   Opts.GPURelocatableDeviceCode = Args.hasArg(OPT_fgpu_rdc);
+  Opts.HIPUseNewLaunchAPI = Args.hasArg(OPT_fhip_new_launch_api);
 
   if (Opts.ObjC) {
     if (Arg *arg = Args.getLastArg(OPT_fobjc_runtime_EQ)) {
@@ -2512,6 +2580,21 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
         (Opts.ObjCRuntime.getKind() == ObjCRuntime::FragileMacOSX);
   }
 
+  if (Arg *A = Args.getLastArg(options::OPT_fgnuc_version_EQ)) {
+    // Check that the version has 1 to 3 components and the minor and patch
+    // versions fit in two decimal digits.
+    VersionTuple GNUCVer;
+    bool Invalid = GNUCVer.tryParse(A->getValue());
+    unsigned Major = GNUCVer.getMajor();
+    unsigned Minor = GNUCVer.getMinor().getValueOr(0);
+    unsigned Patch = GNUCVer.getSubminor().getValueOr(0);
+    if (Invalid || GNUCVer.getBuild() || Minor >= 100 || Patch >= 100) {
+      Diags.Report(diag::err_drv_invalid_value)
+          << A->getAsString(Args) << A->getValue();
+    }
+    Opts.GNUCVersion = Major * 100 * 100 + Minor * 100 + Patch;
+  }
+
   if (Args.hasArg(OPT_fgnu89_inline)) {
     if (Opts.CPlusPlus)
       Diags.Report(diag::err_drv_argument_not_allowed_with)
@@ -2611,8 +2694,18 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
   Opts.WritableStrings = Args.hasArg(OPT_fwritable_strings);
   Opts.ConstStrings = Args.hasFlag(OPT_fconst_strings, OPT_fno_const_strings,
                                    Opts.ConstStrings);
-  if (Args.hasArg(OPT_fno_lax_vector_conversions))
-    Opts.LaxVectorConversions = 0;
+  if (Arg *A = Args.getLastArg(OPT_flax_vector_conversions_EQ)) {
+    using LaxKind = LangOptions::LaxVectorConversionKind;
+    if (auto Kind = llvm::StringSwitch<Optional<LaxKind>>(A->getValue())
+                        .Case("none", LaxKind::None)
+                        .Case("integer", LaxKind::Integer)
+                        .Case("all", LaxKind::All)
+                        .Default(llvm::None))
+      Opts.setLaxVectorConversions(*Kind);
+    else
+      Diags.Report(diag::err_drv_invalid_value)
+          << A->getAsString(Args) << A->getValue();
+  }
   if (Args.hasArg(OPT_fno_threadsafe_statics))
     Opts.ThreadsafeStatics = 0;
   Opts.Exceptions = Args.hasArg(OPT_fexceptions);
@@ -2630,9 +2723,9 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
       Opts.FixedPoint;
 
   // Handle exception personalities
-  Arg *A = Args.getLastArg(options::OPT_fsjlj_exceptions,
-                           options::OPT_fseh_exceptions,
-                           options::OPT_fdwarf_exceptions);
+  Arg *A = Args.getLastArg(
+      options::OPT_fsjlj_exceptions, options::OPT_fseh_exceptions,
+      options::OPT_fdwarf_exceptions, options::OPT_fwasm_exceptions);
   if (A) {
     const Option &Opt = A->getOption();
     llvm::Triple T(TargetOpts.Triple);
@@ -2643,6 +2736,7 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
     Opts.SjLjExceptions = Opt.matches(options::OPT_fsjlj_exceptions);
     Opts.SEHExceptions = Opt.matches(options::OPT_fseh_exceptions);
     Opts.DWARFExceptions = Opt.matches(options::OPT_fdwarf_exceptions);
+    Opts.WasmExceptions = Opt.matches(options::OPT_fwasm_exceptions);
   }
 
   Opts.ExternCNoUnwind = Args.hasArg(OPT_fexternc_nounwind);
@@ -2727,6 +2821,10 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
       getLastArgIntValue(Args, OPT_fconstexpr_depth, 512, Diags);
   Opts.ConstexprStepLimit =
       getLastArgIntValue(Args, OPT_fconstexpr_steps, 1048576, Diags);
+  Opts.EnableNewConstInterp =
+      Args.hasArg(OPT_fexperimental_new_constant_interpreter);
+  Opts.ForceNewConstInterp =
+      Args.hasArg(OPT_fforce_experimental_new_constant_interpreter);
   Opts.BracketDepth = getLastArgIntValue(Args, OPT_fbracket_depth, 256, Diags);
   Opts.DelayedTemplateParsing = Args.hasArg(OPT_fdelayed_template_parsing);
   Opts.NumLargeByValueCopy =
@@ -2876,8 +2974,8 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
     }
   }
 
-  // Check if -fopenmp is specified.
-  Opts.OpenMP = Args.hasArg(options::OPT_fopenmp) ? 1 : 0;
+  // Check if -fopenmp is specified and set default version to 4.5.
+  Opts.OpenMP = Args.hasArg(options::OPT_fopenmp) ? 45 : 0;
   // Check if -fopenmp-simd is specified.
   bool IsSimdSpecified =
       Args.hasFlag(options::OPT_fopenmp_simd, options::OPT_fno_openmp_simd,
@@ -3108,6 +3206,8 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
         Opts.setClangABICompat(LangOptions::ClangABI::Ver6);
       else if (Major <= 7)
         Opts.setClangABICompat(LangOptions::ClangABI::Ver7);
+      else if (Major <= 9)
+        Opts.setClangABICompat(LangOptions::ClangABI::Ver9);
     } else if (Ver != "latest") {
       Diags.Report(diag::err_drv_invalid_value)
           << A->getAsString(Args) << A->getValue();
@@ -3136,8 +3236,7 @@ static bool isStrictlyPreprocessorAction(frontend::ActionKind Action) {
   case frontend::GenerateModuleInterface:
   case frontend::GenerateHeaderModule:
   case frontend::GeneratePCH:
-  case frontend::GenerateInterfaceYAMLExpV1:
-  case frontend::GenerateInterfaceTBEExpV1:
+  case frontend::GenerateInterfaceIfsExpV1:
   case frontend::ParseSyntaxOnly:
   case frontend::ModuleFileInfo:
   case frontend::VerifyPCH:
@@ -3253,6 +3352,8 @@ static void ParsePreprocessorArgs(PreprocessorOptions &Opts, ArgList &Args,
   // "editor placeholder in source file" error in PP only mode.
   if (isStrictlyPreprocessorAction(Action))
     Opts.LexEditorPlaceholders = false;
+
+  Opts.SetUpStaticAnalyzer = Args.hasArg(OPT_setup_static_analyzer);
 }
 
 static void ParsePreprocessorOutputArgs(PreprocessorOutputOptions &Opts,
@@ -3315,18 +3416,16 @@ static void ParseTargetArgs(TargetOptions &Opts, ArgList &Args,
 }
 
 bool CompilerInvocation::CreateFromArgs(CompilerInvocation &Res,
-                                        const char *const *ArgBegin,
-                                        const char *const *ArgEnd,
+                                        ArrayRef<const char *> CommandLineArgs,
                                         DiagnosticsEngine &Diags) {
   bool Success = true;
 
   // Parse the arguments.
-  std::unique_ptr<OptTable> Opts = createDriverOptTable();
+  const OptTable &Opts = getDriverOptTable();
   const unsigned IncludedFlagsBitmask = options::CC1Option;
   unsigned MissingArgIndex, MissingArgCount;
-  InputArgList Args =
-      Opts->ParseArgs(llvm::makeArrayRef(ArgBegin, ArgEnd), MissingArgIndex,
-                      MissingArgCount, IncludedFlagsBitmask);
+  InputArgList Args = Opts.ParseArgs(CommandLineArgs, MissingArgIndex,
+                                     MissingArgCount, IncludedFlagsBitmask);
   LangOptions &LangOpts = *Res.getLangOpts();
 
   // Check for missing argument error.
@@ -3340,7 +3439,7 @@ bool CompilerInvocation::CreateFromArgs(CompilerInvocation &Res,
   for (const auto *A : Args.filtered(OPT_UNKNOWN)) {
     auto ArgString = A->getAsString(Args);
     std::string Nearest;
-    if (Opts->findNearest(ArgString, Nearest, IncludedFlagsBitmask) > 1)
+    if (Opts.findNearest(ArgString, Nearest, IncludedFlagsBitmask) > 1)
       Diags.Report(diag::err_drv_unknown_argument) << ArgString;
     else
       Diags.Report(diag::err_drv_unknown_argument_with_suggestion)
@@ -3351,6 +3450,11 @@ bool CompilerInvocation::CreateFromArgs(CompilerInvocation &Res,
   Success &= ParseAnalyzerArgs(*Res.getAnalyzerOpts(), Args, Diags);
   Success &= ParseMigratorArgs(Res.getMigratorOpts(), Args);
   ParseDependencyOutputArgs(Res.getDependencyOutputOpts(), Args);
+  if (!Res.getDependencyOutputOpts().OutputFile.empty() &&
+      Res.getDependencyOutputOpts().Targets.empty()) {
+    Diags.Report(diag::err_fe_dependency_file_requires_MT);
+    Success = false;
+  }
   Success &=
       ParseDiagnosticArgs(Res.getDiagnosticOpts(), Args, &Diags,
                           false /*DefaultDiagColor*/, false /*DefaultShowOpt*/);
@@ -3366,7 +3470,7 @@ bool CompilerInvocation::CreateFromArgs(CompilerInvocation &Res,
                         Res.getFileSystemOpts().WorkingDir);
   llvm::Triple T(Res.getTargetOpts().Triple);
   if (DashX.getFormat() == InputKind::Precompiled ||
-      DashX.getLanguage() == InputKind::LLVM_IR) {
+      DashX.getLanguage() == Language::LLVM_IR) {
     // ObjCAAutoRefCount and Sanitize LangOpts are used to setup the
     // PassManager in BackendUtil.cpp. They need to be initializd no matter
     // what the input type is.
@@ -3380,7 +3484,7 @@ bool CompilerInvocation::CreateFromArgs(CompilerInvocation &Res,
                         Diags, LangOpts.Sanitize);
   } else {
     // Other LangOpts are only initialized when the input is not AST or LLVM IR.
-    // FIXME: Should we really be calling this for an InputKind::Asm input?
+    // FIXME: Should we really be calling this for an Language::Asm input?
     ParseLangArgs(LangOpts, Args, DashX, Res.getTargetOpts(),
                   Res.getPreprocessorOpts(), Diags);
     if (Res.getFrontendOpts().ProgramAction == frontend::RewriteObjC)
@@ -3393,6 +3497,9 @@ bool CompilerInvocation::CreateFromArgs(CompilerInvocation &Res,
     }
   }
 
+  if (Diags.isIgnored(diag::warn_profile_data_misexpect, SourceLocation()))
+    Res.FrontendOpts.LLVMArgs.push_back("-pgo-warn-misexpect");
+
   LangOpts.FunctionAlignment =
       getLastArgIntValue(Args, OPT_function_alignment, 0, Diags);
 
@@ -3440,6 +3547,7 @@ std::string CompilerInvocation::getModuleHash() const {
   using llvm::hash_code;
   using llvm::hash_value;
   using llvm::hash_combine;
+  using llvm::hash_combine_range;
 
   // Start the signature with the compiler version.
   // FIXME: We'd rather use something more cryptographically sound than
@@ -3494,6 +3602,24 @@ std::string CompilerInvocation::getModuleHash() const {
                       hsOpts.ModulesValidateDiagnosticOptions);
   code = hash_combine(code, hsOpts.ResourceDir);
 
+  if (hsOpts.ModulesStrictContextHash) {
+    hash_code SHPC = hash_combine_range(hsOpts.SystemHeaderPrefixes.begin(),
+                                        hsOpts.SystemHeaderPrefixes.end());
+    hash_code UEC = hash_combine_range(hsOpts.UserEntries.begin(),
+                                       hsOpts.UserEntries.end());
+    code = hash_combine(code, hsOpts.SystemHeaderPrefixes.size(), SHPC,
+                        hsOpts.UserEntries.size(), UEC);
+
+    const DiagnosticOptions &diagOpts = getDiagnosticOpts();
+    #define DIAGOPT(Name, Bits, Default) \
+      code = hash_combine(code, diagOpts.Name);
+    #define ENUM_DIAGOPT(Name, Type, Bits, Default) \
+      code = hash_combine(code, diagOpts.get##Name());
+    #include "clang/Basic/DiagnosticOptions.def"
+    #undef DIAGOPT
+    #undef ENUM_DIAGOPT
+  }
+
   // Extend the signature with the user build path.
   code = hash_combine(code, hsOpts.ModuleUserBuildPath);
 
diff --git a/lib/Frontend/CreateInvocationFromCommandLine.cpp b/lib/Frontend/CreateInvocationFromCommandLine.cpp
index b62416ffd9e7a..ab62b633cda38 100644
--- a/lib/Frontend/CreateInvocationFromCommandLine.cpp
+++ b/lib/Frontend/CreateInvocationFromCommandLine.cpp
@@ -24,14 +24,9 @@
 using namespace clang;
 using namespace llvm::opt;
 
-/// createInvocationFromCommandLine - Construct a compiler invocation object for
-/// a command line argument vector.
-///
-/// \return A CompilerInvocation, or 0 if none was built for the given
-/// argument vector.
 std::unique_ptr<CompilerInvocation> clang::createInvocationFromCommandLine(
     ArrayRef<const char *> ArgList, IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
-    IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) {
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS, bool ShouldRecoverOnErorrs) {
   if (!Diags.get()) {
     // No diagnostics engine was provided, so create our own diagnostics object
     // with the default options.
@@ -94,12 +89,9 @@ std::unique_ptr<CompilerInvocation> clang::createInvocationFromCommandLine(
   }
 
   const ArgStringList &CCArgs = Cmd.getArguments();
-  auto CI = llvm::make_unique<CompilerInvocation>();
-  if (!CompilerInvocation::CreateFromArgs(*CI,
-                                     const_cast<const char **>(CCArgs.data()),
-                                     const_cast<const char **>(CCArgs.data()) +
-                                     CCArgs.size(),
-                                     *Diags))
+  auto CI = std::make_unique<CompilerInvocation>();
+  if (!CompilerInvocation::CreateFromArgs(*CI, CCArgs, *Diags) &&
+      !ShouldRecoverOnErorrs)
     return nullptr;
   return CI;
 }
diff --git a/lib/Frontend/DependencyFile.cpp b/lib/Frontend/DependencyFile.cpp
index 375eb91ae3666..4bb0167bd5976 100644
--- a/lib/Frontend/DependencyFile.cpp
+++ b/lib/Frontend/DependencyFile.cpp
@@ -46,20 +46,20 @@ struct DepCollectorPPCallbacks : public PPCallbacks {
     // 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)
+    Optional<FileEntryRef> File =
+        SM.getFileEntryRefForID(SM.getFileID(SM.getExpansionLoc(Loc)));
+    if (!File)
       return;
 
     StringRef Filename =
-        llvm::sys::path::remove_leading_dotslash(FE->getName());
+        llvm::sys::path::remove_leading_dotslash(File->getName());
 
     DepCollector.maybeAddDependency(Filename, /*FromModule*/false,
                                     isSystem(FileType),
                                     /*IsModuleFile*/false, /*IsMissing*/false);
   }
 
-  void FileSkipped(const FileEntry &SkippedFile, const Token &FilenameTok,
+  void FileSkipped(const FileEntryRef &SkippedFile, const Token &FilenameTok,
                    SrcMgr::CharacteristicKind FileType) override {
     StringRef Filename =
         llvm::sys::path::remove_leading_dotslash(SkippedFile.getName());
@@ -83,7 +83,7 @@ struct DepCollectorPPCallbacks : public PPCallbacks {
   }
 
   void HasInclude(SourceLocation Loc, StringRef SpelledFilename, bool IsAngled,
-                  const FileEntry *File,
+                  Optional<FileEntryRef> File,
                   SrcMgr::CharacteristicKind FileType) override {
     if (!File)
       return;
@@ -168,13 +168,13 @@ bool DependencyCollector::sawDependency(StringRef Filename, bool FromModule,
 
 DependencyCollector::~DependencyCollector() { }
 void DependencyCollector::attachToPreprocessor(Preprocessor &PP) {
-  PP.addPPCallbacks(llvm::make_unique<DepCollectorPPCallbacks>(
+  PP.addPPCallbacks(std::make_unique<DepCollectorPPCallbacks>(
       *this, PP.getSourceManager(), PP.getDiagnostics()));
   PP.getHeaderSearchInfo().getModuleMap().addModuleMapCallbacks(
-      llvm::make_unique<DepCollectorMMCallbacks>(*this));
+      std::make_unique<DepCollectorMMCallbacks>(*this));
 }
 void DependencyCollector::attachToASTReader(ASTReader &R) {
-  R.addListener(llvm::make_unique<DepCollectorASTListener>(*this));
+  R.addListener(std::make_unique<DepCollectorASTListener>(*this));
 }
 
 DependencyFileGenerator::DependencyFileGenerator(
@@ -192,11 +192,6 @@ DependencyFileGenerator::DependencyFileGenerator(
 }
 
 void DependencyFileGenerator::attachToPreprocessor(Preprocessor &PP) {
-  if (Targets.empty()) {
-    PP.getDiagnostics().Report(diag::err_fe_dependency_file_requires_MT);
-    return;
-  }
-
   // Disable the "file not found" diagnostic if the -MG option was given.
   if (AddMissingHeaderDeps)
     PP.SetSuppressIncludeNotFoundError(true);
@@ -316,7 +311,7 @@ void DependencyFileGenerator::outputDependencyFile(DiagnosticsEngine &Diags) {
   }
 
   std::error_code EC;
-  llvm::raw_fd_ostream OS(OutputFile, EC, llvm::sys::fs::F_Text);
+  llvm::raw_fd_ostream OS(OutputFile, EC, llvm::sys::fs::OF_Text);
   if (EC) {
     Diags.Report(diag::err_fe_error_opening) << OutputFile << EC.message();
     return;
diff --git a/lib/Frontend/DependencyGraph.cpp b/lib/Frontend/DependencyGraph.cpp
index 90624323a000a..ccf7a2785510b 100644
--- a/lib/Frontend/DependencyGraph.cpp
+++ b/lib/Frontend/DependencyGraph.cpp
@@ -61,7 +61,7 @@ public:
 
 void clang::AttachDependencyGraphGen(Preprocessor &PP, StringRef OutputFile,
                                      StringRef SysRoot) {
-  PP.addPPCallbacks(llvm::make_unique<DependencyGraphCallback>(&PP, OutputFile,
+  PP.addPPCallbacks(std::make_unique<DependencyGraphCallback>(&PP, OutputFile,
                                                                SysRoot));
 }
 
@@ -100,7 +100,7 @@ DependencyGraphCallback::writeNodeReference(raw_ostream &OS,
 
 void DependencyGraphCallback::OutputGraphFile() {
   std::error_code EC;
-  llvm::raw_fd_ostream OS(OutputFile, EC, llvm::sys::fs::F_Text);
+  llvm::raw_fd_ostream OS(OutputFile, EC, llvm::sys::fs::OF_Text);
   if (EC) {
     PP->getDiagnostics().Report(diag::err_fe_error_opening) << OutputFile
                                                             << EC.message();
diff --git a/lib/Frontend/FrontendAction.cpp b/lib/Frontend/FrontendAction.cpp
index d724bbce3749e..b3b7976f8f3e3 100644
--- a/lib/Frontend/FrontendAction.cpp
+++ b/lib/Frontend/FrontendAction.cpp
@@ -10,6 +10,7 @@
 #include "clang/AST/ASTConsumer.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/DeclGroup.h"
+#include "clang/Basic/LangStandard.h"
 #include "clang/Frontend/ASTUnit.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/FrontendDiagnostic.h"
@@ -215,7 +216,7 @@ FrontendAction::CreateWrappedASTConsumer(CompilerInstance &CI,
     Consumers.push_back(std::move(C));
   }
 
-  return llvm::make_unique<MultiplexConsumer>(std::move(Consumers));
+  return std::make_unique<MultiplexConsumer>(std::move(Consumers));
 }
 
 /// For preprocessed files, if the first line is the linemarker and specifies
@@ -370,7 +371,7 @@ static std::error_code collectModuleHeaderIncludes(
                .Default(false))
         continue;
 
-      const FileEntry *Header = FileMgr.getFile(Dir->path());
+      auto Header = FileMgr.getFile(Dir->path());
       // FIXME: This shouldn't happen unless there is a file system race. Is
       // that worth diagnosing?
       if (!Header)
@@ -378,7 +379,7 @@ static std::error_code collectModuleHeaderIncludes(
 
       // If this header is marked 'unavailable' in this module, don't include
       // it.
-      if (ModMap.isHeaderUnavailableInModule(Header, Module))
+      if (ModMap.isHeaderUnavailableInModule(*Header, Module))
         continue;
 
       // Compute the relative path from the directory to this file.
@@ -392,7 +393,7 @@ static std::error_code collectModuleHeaderIncludes(
         llvm::sys::path::append(RelativeHeader, *It);
 
       // Include this header as part of the umbrella directory.
-      Module->addTopHeader(Header);
+      Module->addTopHeader(*Header);
       addHeaderInclude(RelativeHeader, Includes, LangOpts, Module->IsExternC);
     }
 
@@ -481,7 +482,7 @@ static Module *prepareToBuildModule(CompilerInstance &CI,
   // the module map, rather than adding it after the fact.
   StringRef OriginalModuleMapName = CI.getFrontendOpts().OriginalModuleMap;
   if (!OriginalModuleMapName.empty()) {
-    auto *OriginalModuleMap =
+    auto OriginalModuleMap =
         CI.getFileManager().getFile(OriginalModuleMapName,
                                     /*openFile*/ true);
     if (!OriginalModuleMap) {
@@ -489,11 +490,11 @@ static Module *prepareToBuildModule(CompilerInstance &CI,
         << OriginalModuleMapName;
       return nullptr;
     }
-    if (OriginalModuleMap != CI.getSourceManager().getFileEntryForID(
+    if (*OriginalModuleMap != CI.getSourceManager().getFileEntryForID(
                                  CI.getSourceManager().getMainFileID())) {
       M->IsInferred = true;
       CI.getPreprocessor().getHeaderSearchInfo().getModuleMap()
-        .setInferredModuleAllowedBy(M, OriginalModuleMap);
+        .setInferredModuleAllowedBy(M, *OriginalModuleMap);
     }
   }
 
@@ -674,8 +675,8 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
   // Set up embedding for any specified files. Do this before we load any
   // source files, including the primary module map for the compilation.
   for (const auto &F : CI.getFrontendOpts().ModulesEmbedFiles) {
-    if (const auto *FE = CI.getFileManager().getFile(F, /*openFile*/true))
-      CI.getSourceManager().setFileIsTransient(FE);
+    if (auto FE = CI.getFileManager().getFile(F, /*openFile*/true))
+      CI.getSourceManager().setFileIsTransient(*FE);
     else
       CI.getDiagnostics().Report(diag::err_modules_embed_file_not_found) << F;
   }
@@ -683,7 +684,7 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
     CI.getSourceManager().setAllFilesAreTransient(true);
 
   // IR files bypass the rest of initialization.
-  if (Input.getKind().getLanguage() == InputKind::LLVM_IR) {
+  if (Input.getKind().getLanguage() == Language::LLVM_IR) {
     assert(hasIRSupport() &&
            "This action does not have IR file support!");
 
@@ -709,10 +710,10 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
     PreprocessorOptions &PPOpts = CI.getPreprocessorOpts();
     StringRef PCHInclude = PPOpts.ImplicitPCHInclude;
     std::string SpecificModuleCachePath = CI.getSpecificModuleCachePath();
-    if (const DirectoryEntry *PCHDir = FileMgr.getDirectory(PCHInclude)) {
+    if (auto PCHDir = FileMgr.getDirectory(PCHInclude)) {
       std::error_code EC;
       SmallString<128> DirNative;
-      llvm::sys::path::native(PCHDir->getName(), DirNative);
+      llvm::sys::path::native((*PCHDir)->getName(), DirNative);
       bool Found = false;
       llvm::vfs::FileSystem &FS = FileMgr.getVirtualFileSystem();
       for (llvm::vfs::directory_iterator Dir = FS.dir_begin(DirNative, EC),
@@ -792,9 +793,9 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
 
   // If we were asked to load any module map files, do so now.
   for (const auto &Filename : CI.getFrontendOpts().ModuleMapFiles) {
-    if (auto *File = CI.getFileManager().getFile(Filename))
+    if (auto File = CI.getFileManager().getFile(Filename))
       CI.getPreprocessor().getHeaderSearchInfo().loadModuleMapFile(
-          File, /*IsSystem*/false);
+          *File, /*IsSystem*/false);
     else
       CI.getDiagnostics().Report(diag::err_module_map_not_found) << Filename;
   }
diff --git a/lib/Frontend/FrontendActions.cpp b/lib/Frontend/FrontendActions.cpp
index e37afae5332a0..4d47c768ad3c2 100644
--- a/lib/Frontend/FrontendActions.cpp
+++ b/lib/Frontend/FrontendActions.cpp
@@ -9,6 +9,7 @@
 #include "clang/Frontend/FrontendActions.h"
 #include "clang/AST/ASTConsumer.h"
 #include "clang/Basic/FileManager.h"
+#include "clang/Basic/LangStandard.h"
 #include "clang/Frontend/ASTConsumers.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/FrontendDiagnostic.h"
@@ -54,7 +55,7 @@ void EnsureSemaIsCreated(CompilerInstance &CI, FrontendAction &Action) {
 
 std::unique_ptr<ASTConsumer>
 InitOnlyAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
-  return llvm::make_unique<ASTConsumer>();
+  return std::make_unique<ASTConsumer>();
 }
 
 void InitOnlyAction::ExecuteAction() {
@@ -108,7 +109,7 @@ GeneratePCHAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
   const auto &FrontendOpts = CI.getFrontendOpts();
   auto Buffer = std::make_shared<PCHBuffer>();
   std::vector<std::unique_ptr<ASTConsumer>> Consumers;
-  Consumers.push_back(llvm::make_unique<PCHGenerator>(
+  Consumers.push_back(std::make_unique<PCHGenerator>(
       CI.getPreprocessor(), CI.getModuleCache(), OutputFile, Sysroot, Buffer,
       FrontendOpts.ModuleFileExtensions,
       CI.getPreprocessorOpts().AllowPCHWithCompilerErrors,
@@ -116,7 +117,7 @@ GeneratePCHAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
   Consumers.push_back(CI.getPCHContainerWriter().CreatePCHContainerGenerator(
       CI, InFile, OutputFile, std::move(OS), Buffer));
 
-  return llvm::make_unique<MultiplexConsumer>(std::move(Consumers));
+  return std::make_unique<MultiplexConsumer>(std::move(Consumers));
 }
 
 bool GeneratePCHAction::ComputeASTConsumerArguments(CompilerInstance &CI,
@@ -171,7 +172,7 @@ GenerateModuleAction::CreateASTConsumer(CompilerInstance &CI,
   auto Buffer = std::make_shared<PCHBuffer>();
   std::vector<std::unique_ptr<ASTConsumer>> Consumers;
 
-  Consumers.push_back(llvm::make_unique<PCHGenerator>(
+  Consumers.push_back(std::make_unique<PCHGenerator>(
       CI.getPreprocessor(), CI.getModuleCache(), OutputFile, Sysroot, Buffer,
       CI.getFrontendOpts().ModuleFileExtensions,
       /*AllowASTWithErrors=*/false,
@@ -181,7 +182,7 @@ GenerateModuleAction::CreateASTConsumer(CompilerInstance &CI,
       +CI.getFrontendOpts().BuildingImplicitModule));
   Consumers.push_back(CI.getPCHContainerWriter().CreatePCHContainerGenerator(
       CI, InFile, OutputFile, std::move(OS), Buffer));
-  return llvm::make_unique<MultiplexConsumer>(std::move(Consumers));
+  return std::make_unique<MultiplexConsumer>(std::move(Consumers));
 }
 
 bool GenerateModuleFromModuleMapAction::BeginSourceFileAction(
@@ -286,15 +287,15 @@ bool GenerateHeaderModuleAction::BeginSourceFileAction(
   SmallVector<Module::Header, 16> Headers;
   for (StringRef Name : ModuleHeaders) {
     const DirectoryLookup *CurDir = nullptr;
-    const FileEntry *FE = HS.LookupFile(
-        Name, SourceLocation(), /*Angled*/ false, nullptr, CurDir,
-        None, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr);
+    Optional<FileEntryRef> FE = HS.LookupFile(
+        Name, SourceLocation(), /*Angled*/ false, nullptr, CurDir, None,
+        nullptr, nullptr, nullptr, nullptr, nullptr, nullptr);
     if (!FE) {
       CI.getDiagnostics().Report(diag::err_module_header_file_not_found)
         << Name;
       continue;
     }
-    Headers.push_back({Name, FE});
+    Headers.push_back({Name, &FE->getFileEntry()});
   }
   HS.getModuleMap().createHeaderModule(CI.getLangOpts().CurrentModule, Headers);
 
@@ -312,18 +313,18 @@ SyntaxOnlyAction::~SyntaxOnlyAction() {
 
 std::unique_ptr<ASTConsumer>
 SyntaxOnlyAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
-  return llvm::make_unique<ASTConsumer>();
+  return std::make_unique<ASTConsumer>();
 }
 
 std::unique_ptr<ASTConsumer>
 DumpModuleInfoAction::CreateASTConsumer(CompilerInstance &CI,
                                         StringRef InFile) {
-  return llvm::make_unique<ASTConsumer>();
+  return std::make_unique<ASTConsumer>();
 }
 
 std::unique_ptr<ASTConsumer>
 VerifyPCHAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
-  return llvm::make_unique<ASTConsumer>();
+  return std::make_unique<ASTConsumer>();
 }
 
 void VerifyPCHAction::ExecuteAction() {
@@ -414,8 +415,14 @@ private:
       return "DeclaringSpecialMember";
     case CodeSynthesisContext::DefiningSynthesizedFunction:
       return "DefiningSynthesizedFunction";
+    case CodeSynthesisContext::RewritingOperatorAsSpaceship:
+      return "RewritingOperatorAsSpaceship";
     case CodeSynthesisContext::Memoization:
       return "Memoization";
+    case CodeSynthesisContext::ConstraintsCheck:
+      return "ConstraintsCheck";
+    case CodeSynthesisContext::ConstraintSubstitution:
+      return "ConstraintSubstitution";
     }
     return "";
   }
@@ -465,7 +472,7 @@ private:
 
 std::unique_ptr<ASTConsumer>
 TemplightDumpAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
-  return llvm::make_unique<ASTConsumer>();
+  return std::make_unique<ASTConsumer>();
 }
 
 void TemplightDumpAction::ExecuteAction() {
@@ -478,7 +485,7 @@ void TemplightDumpAction::ExecuteAction() {
   EnsureSemaIsCreated(CI, *this);
 
   CI.getSema().TemplateInstCallbacks.push_back(
-      llvm::make_unique<DefaultTemplateInstCallback>());
+      std::make_unique<DefaultTemplateInstCallback>());
   ASTFrontendAction::ExecuteAction();
 }
 
@@ -695,7 +702,7 @@ void DumpModuleInfoAction::ExecuteAction() {
   if (!OutputFileName.empty() && OutputFileName != "-") {
     std::error_code EC;
     OutFile.reset(new llvm::raw_fd_ostream(OutputFileName.str(), EC,
-                                           llvm::sys::fs::F_Text));
+                                           llvm::sys::fs::OF_Text));
   }
   llvm::raw_ostream &Out = OutFile.get()? *OutFile.get() : llvm::outs();
 
@@ -832,19 +839,19 @@ void PrintPreprocessedAction::ExecuteAction() {
 
 void PrintPreambleAction::ExecuteAction() {
   switch (getCurrentFileKind().getLanguage()) {
-  case InputKind::C:
-  case InputKind::CXX:
-  case InputKind::ObjC:
-  case InputKind::ObjCXX:
-  case InputKind::OpenCL:
-  case InputKind::CUDA:
-  case InputKind::HIP:
+  case Language::C:
+  case Language::CXX:
+  case Language::ObjC:
+  case Language::ObjCXX:
+  case Language::OpenCL:
+  case Language::CUDA:
+  case Language::HIP:
     break;
 
-  case InputKind::Unknown:
-  case InputKind::Asm:
-  case InputKind::LLVM_IR:
-  case InputKind::RenderScript:
+  case Language::Unknown:
+  case Language::Asm:
+  case Language::LLVM_IR:
+  case Language::RenderScript:
     // We can't do anything with these.
     return;
   }
@@ -927,7 +934,7 @@ void PrintDependencyDirectivesSourceMinimizerAction::ExecuteAction() {
     // 'expected' comments.
     if (CI.getDiagnosticOpts().VerifyDiagnostics) {
       // Make sure we don't emit new diagnostics!
-      CI.getDiagnostics().setSuppressAllDiagnostics();
+      CI.getDiagnostics().setSuppressAllDiagnostics(true);
       Preprocessor &PP = getCompilerInstance().getPreprocessor();
       PP.EnterMainSourceFile();
       Token Tok;
diff --git a/lib/Frontend/FrontendOptions.cpp b/lib/Frontend/FrontendOptions.cpp
index 6ccb2c3956040..5c1fbf889c23b 100644
--- a/lib/Frontend/FrontendOptions.cpp
+++ b/lib/Frontend/FrontendOptions.cpp
@@ -7,28 +7,29 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Frontend/FrontendOptions.h"
+#include "clang/Basic/LangStandard.h"
 #include "llvm/ADT/StringSwitch.h"
 
 using namespace clang;
 
 InputKind FrontendOptions::getInputKindForExtension(StringRef Extension) {
   return llvm::StringSwitch<InputKind>(Extension)
-    .Cases("ast", "pcm", InputKind(InputKind::Unknown, InputKind::Precompiled))
-    .Case("c", InputKind::C)
-    .Cases("S", "s", InputKind::Asm)
-    .Case("i", InputKind(InputKind::C).getPreprocessed())
-    .Case("ii", InputKind(InputKind::CXX).getPreprocessed())
-    .Case("cui", InputKind(InputKind::CUDA).getPreprocessed())
-    .Case("m", InputKind::ObjC)
-    .Case("mi", InputKind(InputKind::ObjC).getPreprocessed())
-    .Cases("mm", "M", InputKind::ObjCXX)
-    .Case("mii", InputKind(InputKind::ObjCXX).getPreprocessed())
-    .Cases("C", "cc", "cp", InputKind::CXX)
-    .Cases("cpp", "CPP", "c++", "cxx", "hpp", InputKind::CXX)
-    .Case("cppm", InputKind::CXX)
-    .Case("iim", InputKind(InputKind::CXX).getPreprocessed())
-    .Case("cl", InputKind::OpenCL)
-    .Case("cu", InputKind::CUDA)
-    .Cases("ll", "bc", InputKind::LLVM_IR)
-    .Default(InputKind::Unknown);
+      .Cases("ast", "pcm", InputKind(Language::Unknown, InputKind::Precompiled))
+      .Case("c", Language::C)
+      .Cases("S", "s", Language::Asm)
+      .Case("i", InputKind(Language::C).getPreprocessed())
+      .Case("ii", InputKind(Language::CXX).getPreprocessed())
+      .Case("cui", InputKind(Language::CUDA).getPreprocessed())
+      .Case("m", Language::ObjC)
+      .Case("mi", InputKind(Language::ObjC).getPreprocessed())
+      .Cases("mm", "M", Language::ObjCXX)
+      .Case("mii", InputKind(Language::ObjCXX).getPreprocessed())
+      .Cases("C", "cc", "cp", Language::CXX)
+      .Cases("cpp", "CPP", "c++", "cxx", "hpp", Language::CXX)
+      .Case("cppm", Language::CXX)
+      .Case("iim", InputKind(Language::CXX).getPreprocessed())
+      .Case("cl", Language::OpenCL)
+      .Case("cu", Language::CUDA)
+      .Cases("ll", "bc", Language::LLVM_IR)
+      .Default(Language::Unknown);
 }
diff --git a/lib/Frontend/HeaderIncludeGen.cpp b/lib/Frontend/HeaderIncludeGen.cpp
index d60f5333bf5bf..5f91157816b03 100644
--- a/lib/Frontend/HeaderIncludeGen.cpp
+++ b/lib/Frontend/HeaderIncludeGen.cpp
@@ -100,7 +100,8 @@ void clang::AttachHeaderIncludeGen(Preprocessor &PP,
   if (!OutputPath.empty()) {
     std::error_code EC;
     llvm::raw_fd_ostream *OS = new llvm::raw_fd_ostream(
-        OutputPath.str(), EC, llvm::sys::fs::F_Append | llvm::sys::fs::F_Text);
+        OutputPath.str(), EC,
+        llvm::sys::fs::OF_Append | llvm::sys::fs::OF_Text);
     if (EC) {
       PP.getDiagnostics().Report(clang::diag::warn_fe_cc_print_header_failure)
           << EC.message();
@@ -119,7 +120,7 @@ void clang::AttachHeaderIncludeGen(Preprocessor &PP,
   // the GNU way to generate rules is -M / -MM / -MD / -MMD.
   for (const auto &Header : DepOpts.ExtraDeps)
     PrintHeaderInfo(OutputFile, Header, ShowDepth, 2, MSStyle);
-  PP.addPPCallbacks(llvm::make_unique<HeaderIncludesCallback>(
+  PP.addPPCallbacks(std::make_unique<HeaderIncludesCallback>(
       &PP, ShowAllHeaders, OutputFile, DepOpts, OwnsOutputFile, ShowDepth,
       MSStyle));
 }
diff --git a/lib/Frontend/InitHeaderSearch.cpp b/lib/Frontend/InitHeaderSearch.cpp
index d65d13489dc42..5d877ee9c0d73 100644
--- a/lib/Frontend/InitHeaderSearch.cpp
+++ b/lib/Frontend/InitHeaderSearch.cpp
@@ -137,6 +137,13 @@ bool InitHeaderSearch::AddUnmappedPath(const Twine &Path, IncludeDirGroup Group,
   SmallString<256> MappedPathStorage;
   StringRef MappedPathStr = Path.toStringRef(MappedPathStorage);
 
+  // If use system headers while cross-compiling, emit the warning.
+  if (HasSysroot && (MappedPathStr.startswith("/usr/include") ||
+                     MappedPathStr.startswith("/usr/local/include"))) {
+    Headers.getDiags().Report(diag::warn_poison_system_directories)
+        << MappedPathStr;
+  }
+
   // Compute the DirectoryLookup type.
   SrcMgr::CharacteristicKind Type;
   if (Group == Quoted || Group == Angled || Group == IndexHeaderMap) {
@@ -148,17 +155,17 @@ bool InitHeaderSearch::AddUnmappedPath(const Twine &Path, IncludeDirGroup Group,
   }
 
   // If the directory exists, add it.
-  if (const DirectoryEntry *DE = FM.getDirectory(MappedPathStr)) {
+  if (auto DE = FM.getOptionalDirectoryRef(MappedPathStr)) {
     IncludePath.push_back(
-      std::make_pair(Group, DirectoryLookup(DE, Type, isFramework)));
+      std::make_pair(Group, DirectoryLookup(*DE, Type, isFramework)));
     return true;
   }
 
   // Check to see if this is an apple-style headermap (which are not allowed to
   // be frameworks).
   if (!isFramework) {
-    if (const FileEntry *FE = FM.getFile(MappedPathStr)) {
-      if (const HeaderMap *HM = Headers.CreateHeaderMap(FE)) {
+    if (auto FE = FM.getFile(MappedPathStr)) {
+      if (const HeaderMap *HM = Headers.CreateHeaderMap(*FE)) {
         // It is a headermap, add it to the search path.
         IncludePath.push_back(
           std::make_pair(Group,
@@ -636,8 +643,8 @@ void clang::ApplyHeaderSearchOptions(HeaderSearch &HS,
     // Set up the builtin include directory in the module map.
     SmallString<128> P = StringRef(HSOpts.ResourceDir);
     llvm::sys::path::append(P, "include");
-    if (const DirectoryEntry *Dir = HS.getFileMgr().getDirectory(P))
-      HS.getModuleMap().setBuiltinIncludeDir(Dir);
+    if (auto Dir = HS.getFileMgr().getDirectory(P))
+      HS.getModuleMap().setBuiltinIncludeDir(*Dir);
   }
 
   Init.Realize(Lang);
diff --git a/lib/Frontend/InitPreprocessor.cpp b/lib/Frontend/InitPreprocessor.cpp
index 3906e2ae1b985..c27c33c530f68 100644
--- a/lib/Frontend/InitPreprocessor.cpp
+++ b/lib/Frontend/InitPreprocessor.cpp
@@ -24,6 +24,7 @@
 #include "clang/Lex/PreprocessorOptions.h"
 #include "clang/Serialization/ASTReader.h"
 #include "llvm/ADT/APFloat.h"
+#include "llvm/IR/DataLayout.h"
 using namespace clang;
 
 static bool MacroBodyEndsInBackslash(StringRef MacroBody) {
@@ -437,17 +438,17 @@ static void InitializeStandardPredefinedMacros(const TargetInfo &TI,
       default:
         llvm_unreachable("Unsupported OpenCL version");
       }
-      Builder.defineMacro("CL_VERSION_1_0", "100");
-      Builder.defineMacro("CL_VERSION_1_1", "110");
-      Builder.defineMacro("CL_VERSION_1_2", "120");
-      Builder.defineMacro("CL_VERSION_2_0", "200");
+    }
+    Builder.defineMacro("CL_VERSION_1_0", "100");
+    Builder.defineMacro("CL_VERSION_1_1", "110");
+    Builder.defineMacro("CL_VERSION_1_2", "120");
+    Builder.defineMacro("CL_VERSION_2_0", "200");
 
-      if (TI.isLittleEndian())
-        Builder.defineMacro("__ENDIAN_LITTLE__");
+    if (TI.isLittleEndian())
+      Builder.defineMacro("__ENDIAN_LITTLE__");
 
-      if (LangOpts.FastRelaxedMath)
-        Builder.defineMacro("__FAST_RELAXED_MATH__");
-    }
+    if (LangOpts.FastRelaxedMath)
+      Builder.defineMacro("__FAST_RELAXED_MATH__");
   }
   // Not "standard" per se, but available even with the -undef flag.
   if (LangOpts.AsmPreprocessor)
@@ -480,6 +481,7 @@ static void InitializeCPlusPlusFeatureTestMacros(const LangOptions &LangOpts,
     Builder.defineMacro("__cpp_user_defined_literals", "200809L");
     Builder.defineMacro("__cpp_lambdas", "200907L");
     Builder.defineMacro("__cpp_constexpr",
+                        LangOpts.CPlusPlus2a ? "201907L" :
                         LangOpts.CPlusPlus17 ? "201603L" :
                         LangOpts.CPlusPlus14 ? "201304L" : "200704");
     Builder.defineMacro("__cpp_range_based_for",
@@ -540,8 +542,11 @@ static void InitializeCPlusPlusFeatureTestMacros(const LangOptions &LangOpts,
     Builder.defineMacro("__cpp_template_template_args", "201611L");
 
   // C++20 features.
-  if (LangOpts.CPlusPlus2a)
+  if (LangOpts.CPlusPlus2a) {
     Builder.defineMacro("__cpp_conditional_explicit", "201806L");
+    Builder.defineMacro("__cpp_constexpr_dynamic_alloc", "201907L");
+    Builder.defineMacro("__cpp_constinit", "201907L");
+  }
   if (LangOpts.Char8)
     Builder.defineMacro("__cpp_char8_t", "201811L");
   Builder.defineMacro("__cpp_impl_destroying_delete", "201806L");
@@ -556,6 +561,7 @@ static void InitializeCPlusPlusFeatureTestMacros(const LangOptions &LangOpts,
 static void InitializePredefinedMacros(const TargetInfo &TI,
                                        const LangOptions &LangOpts,
                                        const FrontendOptions &FEOpts,
+                                       const PreprocessorOptions &PPOpts,
                                        MacroBuilder &Builder) {
   // Compiler version introspection macros.
   Builder.defineMacro("__llvm__");  // LLVM Backend
@@ -570,13 +576,22 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
   Builder.defineMacro("__clang_version__",
                       "\"" CLANG_VERSION_STRING " "
                       + getClangFullRepositoryVersion() + "\"");
-  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");
-    Builder.defineMacro("__GNUC_PATCHLEVEL__", "1");
-    Builder.defineMacro("__GNUC__", "4");
+
+  if (LangOpts.GNUCVersion != 0) {
+    // Major, minor, patch, are given two decimal places each, so 4.2.1 becomes
+    // 40201.
+    unsigned GNUCMajor = LangOpts.GNUCVersion / 100 / 100;
+    unsigned GNUCMinor = LangOpts.GNUCVersion / 100 % 100;
+    unsigned GNUCPatch = LangOpts.GNUCVersion % 100;
+    Builder.defineMacro("__GNUC__", Twine(GNUCMajor));
+    Builder.defineMacro("__GNUC_MINOR__", Twine(GNUCMinor));
+    Builder.defineMacro("__GNUC_PATCHLEVEL__", Twine(GNUCPatch));
     Builder.defineMacro("__GXX_ABI_VERSION", "1002");
+
+    if (LangOpts.CPlusPlus) {
+      Builder.defineMacro("__GNUG__", Twine(GNUCMajor));
+      Builder.defineMacro("__GXX_WEAK__");
+    }
   }
 
   // Define macros for the C11 / C++11 memory orderings
@@ -615,7 +630,7 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
   if (!LangOpts.GNUMode && !LangOpts.MSVCCompat)
     Builder.defineMacro("__STRICT_ANSI__");
 
-  if (!LangOpts.MSVCCompat && LangOpts.CPlusPlus11)
+  if (LangOpts.GNUCVersion && LangOpts.CPlusPlus11)
     Builder.defineMacro("__GXX_EXPERIMENTAL_CXX0X__");
 
   if (LangOpts.ObjC) {
@@ -695,7 +710,7 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
 
   if (!LangOpts.MSVCCompat && LangOpts.Exceptions)
     Builder.defineMacro("__EXCEPTIONS");
-  if (!LangOpts.MSVCCompat && LangOpts.RTTI)
+  if (LangOpts.GNUCVersion && LangOpts.RTTI)
     Builder.defineMacro("__GXX_RTTI");
 
   if (LangOpts.SjLjExceptions)
@@ -709,11 +724,8 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
   if (LangOpts.Deprecated)
     Builder.defineMacro("__DEPRECATED");
 
-  if (!LangOpts.MSVCCompat && LangOpts.CPlusPlus) {
-    Builder.defineMacro("__GNUG__", "4");
-    Builder.defineMacro("__GXX_WEAK__");
+  if (!LangOpts.MSVCCompat && LangOpts.CPlusPlus)
     Builder.defineMacro("__private_extern__", "extern");
-  }
 
   if (LangOpts.MicrosoftExt) {
     if (LangOpts.WChar) {
@@ -923,7 +935,7 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
   else
     Builder.defineMacro("__FINITE_MATH_ONLY__", "0");
 
-  if (!LangOpts.MSVCCompat) {
+  if (LangOpts.GNUCVersion) {
     if (LangOpts.GNUInline || LangOpts.CPlusPlus)
       Builder.defineMacro("__GNUC_GNU_INLINE__");
     else
@@ -960,7 +972,7 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
 #undef DEFINE_LOCK_FREE_MACRO
   };
   addLockFreeMacros("__CLANG_ATOMIC_");
-  if (!LangOpts.MSVCCompat)
+  if (LangOpts.GNUCVersion)
     addLockFreeMacros("__GCC_ATOMIC_");
 
   if (LangOpts.NoInlineDefine)
@@ -987,8 +999,7 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
   else if (LangOpts.getStackProtector() == LangOptions::SSPReq)
     Builder.defineMacro("__SSP_ALL__", "3");
 
-  // Define a macro that exists only when using the static analyzer.
-  if (FEOpts.ProgramAction == frontend::RunAnalysis)
+  if (PPOpts.SetUpStaticAnalyzer)
     Builder.defineMacro("__clang_analyzer__");
 
   if (LangOpts.FastRelaxedMath)
@@ -1032,15 +1043,18 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
     switch (LangOpts.OpenMP) {
     case 0:
       break;
+    case 31:
+      Builder.defineMacro("_OPENMP", "201107");
+      break;
     case 40:
       Builder.defineMacro("_OPENMP", "201307");
       break;
-    case 45:
-      Builder.defineMacro("_OPENMP", "201511");
+    case 50:
+      Builder.defineMacro("_OPENMP", "201811");
       break;
     default:
-      // Default version is OpenMP 3.1
-      Builder.defineMacro("_OPENMP", "201107");
+      // Default version is OpenMP 4.5
+      Builder.defineMacro("_OPENMP", "201511");
       break;
     }
   }
@@ -1112,9 +1126,10 @@ void clang::InitializePreprocessor(
     // macros. This is not the right way to handle this.
     if ((LangOpts.CUDA || LangOpts.OpenMPIsDevice) && PP.getAuxTargetInfo())
       InitializePredefinedMacros(*PP.getAuxTargetInfo(), LangOpts, FEOpts,
-                                 Builder);
+                                 PP.getPreprocessorOpts(), Builder);
 
-    InitializePredefinedMacros(PP.getTargetInfo(), LangOpts, FEOpts, Builder);
+    InitializePredefinedMacros(PP.getTargetInfo(), LangOpts, FEOpts,
+                               PP.getPreprocessorOpts(), Builder);
 
     // Install definitions to make Objective-C++ ARC work well with various
     // C++ Standard Library implementations.
diff --git a/lib/Frontend/InterfaceStubFunctionsConsumer.cpp b/lib/Frontend/InterfaceStubFunctionsConsumer.cpp
index fbba9ae4d6a73..0b28b78de3b13 100644
--- a/lib/Frontend/InterfaceStubFunctionsConsumer.cpp
+++ b/lib/Frontend/InterfaceStubFunctionsConsumer.cpp
@@ -15,6 +15,7 @@
 
 using namespace clang;
 
+namespace {
 class InterfaceStubFunctionsConsumer : public ASTConsumer {
   CompilerInstance &Instance;
   StringRef InFile;
@@ -176,6 +177,10 @@ class InterfaceStubFunctionsConsumer : public ASTConsumer {
       HandleTemplateSpecializations(*cast<FunctionTemplateDecl>(ND), Symbols,
                                     RDO);
       return true;
+    case Decl::Kind::Record:
+    case Decl::Kind::Typedef:
+    case Decl::Kind::Enum:
+    case Decl::Kind::EnumConstant:
     case Decl::Kind::TemplateTypeParm:
       return true;
     case Decl::Kind::Var:
@@ -246,92 +251,27 @@ public:
     for (const NamedDecl *ND : v.NamedDecls)
       HandleNamedDecl(ND, Symbols, FromTU);
 
-    auto writeIfoYaml = [this](const llvm::Triple &T,
-                               const MangledSymbols &Symbols,
-                               const ASTContext &context, StringRef Format,
-                               raw_ostream &OS) -> void {
-      OS << "--- !" << Format << "\n";
-      OS << "FileHeader:\n";
-      OS << "  Class:           ELFCLASS";
-      OS << (T.isArch64Bit() ? "64" : "32");
-      OS << "\n";
-      OS << "  Data:            ELFDATA2";
-      OS << (T.isLittleEndian() ? "LSB" : "MSB");
-      OS << "\n";
-      OS << "  Type:            ET_REL\n";
-      OS << "  Machine:         "
-         << llvm::StringSwitch<llvm::StringRef>(T.getArchName())
-                .Case("x86_64", "EM_X86_64")
-                .Case("i386", "EM_386")
-                .Case("i686", "EM_386")
-                .Case("aarch64", "EM_AARCH64")
-                .Case("amdgcn", "EM_AMDGPU")
-                .Case("r600", "EM_AMDGPU")
-                .Case("arm", "EM_ARM")
-                .Case("thumb", "EM_ARM")
-                .Case("avr", "EM_AVR")
-                .Case("mips", "EM_MIPS")
-                .Case("mipsel", "EM_MIPS")
-                .Case("mips64", "EM_MIPS")
-                .Case("mips64el", "EM_MIPS")
-                .Case("msp430", "EM_MSP430")
-                .Case("ppc", "EM_PPC")
-                .Case("ppc64", "EM_PPC64")
-                .Case("ppc64le", "EM_PPC64")
-                .Case("x86", T.isOSIAMCU() ? "EM_IAMCU" : "EM_386")
-                .Case("x86_64", "EM_X86_64")
-                .Default("EM_NONE")
-         << "\nSymbols:\n";
-      for (const auto &E : Symbols) {
-        const MangledSymbol &Symbol = E.second;
-        for (auto Name : Symbol.Names) {
-          OS << "  - Name:            "
-             << (Symbol.ParentName.empty() || Instance.getLangOpts().CPlusPlus
-                     ? ""
-                     : (Symbol.ParentName + "."))
-             << Name << "\n"
-             << "    Type:            STT_";
-          switch (Symbol.Type) {
-          default:
-          case llvm::ELF::STT_NOTYPE:
-            OS << "NOTYPE";
-            break;
-          case llvm::ELF::STT_OBJECT:
-            OS << "OBJECT";
-            break;
-          case llvm::ELF::STT_FUNC:
-            OS << "FUNC";
-            break;
-          }
-          OS << "\n    Binding:         STB_"
-             << ((Symbol.Binding == llvm::ELF::STB_WEAK) ? "WEAK" : "GLOBAL")
-             << "\n";
-        }
-      }
-      OS << "...\n";
-      OS.flush();
-    };
-
-    auto writeIfoElfAbiYaml =
+    auto writeIfsV1 =
         [this](const llvm::Triple &T, const MangledSymbols &Symbols,
                const ASTContext &context, StringRef Format,
                raw_ostream &OS) -> void {
       OS << "--- !" << Format << "\n";
-      OS << "TbeVersion: 1.0\n";
-      OS << "Arch: " << T.getArchName() << "\n";
+      OS << "IfsVersion: 1.0\n";
+      OS << "Triple: " << T.str() << "\n";
+      OS << "ObjectFileFormat: " << "ELF" << "\n"; // TODO: For now, just ELF.
       OS << "Symbols:\n";
       for (const auto &E : Symbols) {
         const MangledSymbol &Symbol = E.second;
         for (auto Name : Symbol.Names) {
-          OS << "  "
+          OS << "  \""
              << (Symbol.ParentName.empty() || Instance.getLangOpts().CPlusPlus
                      ? ""
                      : (Symbol.ParentName + "."))
-             << Name << ": { Type: ";
+             << Name << "\" : { Type: ";
           switch (Symbol.Type) {
           default:
             llvm_unreachable(
-                "clang -emit-iterface-stubs: Unexpected symbol type.");
+                "clang -emit-interface-stubs: Unexpected symbol type.");
           case llvm::ELF::STT_NOTYPE:
             OS << "NoType";
             break;
@@ -354,25 +294,15 @@ public:
       OS.flush();
     };
 
-    if (Format == "experimental-yaml-elf-v1")
-      writeIfoYaml(Instance.getTarget().getTriple(), Symbols, context, Format,
-                   *OS);
-    else
-      writeIfoElfAbiYaml(Instance.getTarget().getTriple(), Symbols, context,
-                         Format, *OS);
+    assert(Format == "experimental-ifs-v1" && "Unexpected IFS Format.");
+    writeIfsV1(Instance.getTarget().getTriple(), Symbols, context, Format, *OS);
   }
 };
+} // namespace
 
 std::unique_ptr<ASTConsumer>
-GenerateInterfaceYAMLExpV1Action::CreateASTConsumer(CompilerInstance &CI,
-                                                    StringRef InFile) {
-  return llvm::make_unique<InterfaceStubFunctionsConsumer>(
-      CI, InFile, "experimental-yaml-elf-v1");
-}
-
-std::unique_ptr<ASTConsumer>
-GenerateInterfaceTBEExpV1Action::CreateASTConsumer(CompilerInstance &CI,
+GenerateInterfaceIfsExpV1Action::CreateASTConsumer(CompilerInstance &CI,
                                                    StringRef InFile) {
-  return llvm::make_unique<InterfaceStubFunctionsConsumer>(
-      CI, InFile, "experimental-tapi-elf-v1");
+  return std::make_unique<InterfaceStubFunctionsConsumer>(
+      CI, InFile, "experimental-ifs-v1");
 }
diff --git a/lib/Frontend/LangStandards.cpp b/lib/Frontend/LangStandards.cpp
deleted file mode 100644
index 05087eb41f01d..0000000000000
--- a/lib/Frontend/LangStandards.cpp
+++ /dev/null
@@ -1,42 +0,0 @@
-//===--- LangStandards.cpp - Language Standard Definitions ----------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#include "clang/Frontend/LangStandard.h"
-#include "llvm/ADT/StringSwitch.h"
-#include "llvm/Support/ErrorHandling.h"
-using namespace clang;
-using namespace clang::frontend;
-
-#define LANGSTANDARD(id, name, lang, desc, features) \
-static const LangStandard Lang_##id = { name, desc, features, InputKind::lang };
-#include "clang/Frontend/LangStandards.def"
-
-const LangStandard &LangStandard::getLangStandardForKind(Kind K) {
-  switch (K) {
-  case lang_unspecified:
-    llvm::report_fatal_error("getLangStandardForKind() on unspecified kind");
-#define LANGSTANDARD(id, name, lang, desc, features) \
-    case lang_##id: return Lang_##id;
-#include "clang/Frontend/LangStandards.def"
-  }
-  llvm_unreachable("Invalid language kind!");
-}
-
-const LangStandard *LangStandard::getLangStandardForName(StringRef Name) {
-  Kind K = llvm::StringSwitch<Kind>(Name)
-#define LANGSTANDARD(id, name, lang, desc, features) \
-    .Case(name, lang_##id)
-#include "clang/Frontend/LangStandards.def"
-    .Default(lang_unspecified);
-  if (K == lang_unspecified)
-    return nullptr;
-
-  return &getLangStandardForKind(K);
-}
-
-
diff --git a/lib/Frontend/ModuleDependencyCollector.cpp b/lib/Frontend/ModuleDependencyCollector.cpp
index c1d8c0d9eb24c..fd22433d31bdf 100644
--- a/lib/Frontend/ModuleDependencyCollector.cpp
+++ b/lib/Frontend/ModuleDependencyCollector.cpp
@@ -99,14 +99,14 @@ struct ModuleDependencyMMCallbacks : public ModuleMapCallbacks {
 }
 
 void ModuleDependencyCollector::attachToASTReader(ASTReader &R) {
-  R.addListener(llvm::make_unique<ModuleDependencyListener>(*this));
+  R.addListener(std::make_unique<ModuleDependencyListener>(*this));
 }
 
 void ModuleDependencyCollector::attachToPreprocessor(Preprocessor &PP) {
-  PP.addPPCallbacks(llvm::make_unique<ModuleDependencyPPCallbacks>(
+  PP.addPPCallbacks(std::make_unique<ModuleDependencyPPCallbacks>(
       *this, PP.getSourceManager()));
   PP.getHeaderSearchInfo().getModuleMap().addModuleMapCallbacks(
-      llvm::make_unique<ModuleDependencyMMCallbacks>(*this));
+      std::make_unique<ModuleDependencyMMCallbacks>(*this));
 }
 
 static bool isCaseSensitivePath(StringRef Path) {
@@ -148,7 +148,7 @@ void ModuleDependencyCollector::writeFileMap() {
   std::error_code EC;
   SmallString<256> YAMLPath = VFSDir;
   llvm::sys::path::append(YAMLPath, "vfs.yaml");
-  llvm::raw_fd_ostream OS(YAMLPath, EC, llvm::sys::fs::F_Text);
+  llvm::raw_fd_ostream OS(YAMLPath, EC, llvm::sys::fs::OF_Text);
   if (EC) {
     HasErrors = true;
     return;
diff --git a/lib/Frontend/MultiplexConsumer.cpp b/lib/Frontend/MultiplexConsumer.cpp
index ed7028769d349..04e896296c95c 100644
--- a/lib/Frontend/MultiplexConsumer.cpp
+++ b/lib/Frontend/MultiplexConsumer.cpp
@@ -249,11 +249,11 @@ MultiplexConsumer::MultiplexConsumer(
   }
   if (!mutationListeners.empty()) {
     MutationListener =
-        llvm::make_unique<MultiplexASTMutationListener>(mutationListeners);
+        std::make_unique<MultiplexASTMutationListener>(mutationListeners);
   }
   if (!serializationListeners.empty()) {
     DeserializationListener =
-        llvm::make_unique<MultiplexASTDeserializationListener>(
+        std::make_unique<MultiplexASTDeserializationListener>(
             serializationListeners);
   }
 }
diff --git a/lib/Frontend/PrecompiledPreamble.cpp b/lib/Frontend/PrecompiledPreamble.cpp
index 276a9676eaa97..ced32c670288e 100644
--- a/lib/Frontend/PrecompiledPreamble.cpp
+++ b/lib/Frontend/PrecompiledPreamble.cpp
@@ -12,6 +12,7 @@
 
 #include "clang/Frontend/PrecompiledPreamble.h"
 #include "clang/AST/DeclObjC.h"
+#include "clang/Basic/LangStandard.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/CompilerInvocation.h"
@@ -26,11 +27,10 @@
 #include "llvm/Config/llvm-config.h"
 #include "llvm/Support/CrashRecoveryContext.h"
 #include "llvm/Support/FileSystem.h"
-#include "llvm/Support/Mutex.h"
-#include "llvm/Support/MutexGuard.h"
 #include "llvm/Support/Process.h"
 #include "llvm/Support/VirtualFileSystem.h"
 #include <limits>
+#include <mutex>
 #include <utility>
 
 using namespace clang;
@@ -95,7 +95,7 @@ public:
   void removeFile(StringRef File);
 
 private:
-  llvm::sys::SmartMutex<false> Mutex;
+  std::mutex Mutex;
   llvm::StringSet<> Files;
 };
 
@@ -105,20 +105,20 @@ TemporaryFiles &TemporaryFiles::getInstance() {
 }
 
 TemporaryFiles::~TemporaryFiles() {
-  llvm::MutexGuard Guard(Mutex);
+  std::lock_guard<std::mutex> Guard(Mutex);
   for (const auto &File : Files)
     llvm::sys::fs::remove(File.getKey());
 }
 
 void TemporaryFiles::addFile(StringRef File) {
-  llvm::MutexGuard Guard(Mutex);
+  std::lock_guard<std::mutex> Guard(Mutex);
   auto IsInserted = Files.insert(File).second;
   (void)IsInserted;
   assert(IsInserted && "File has already been added");
 }
 
 void TemporaryFiles::removeFile(StringRef File) {
-  llvm::MutexGuard Guard(Mutex);
+  std::lock_guard<std::mutex> Guard(Mutex);
   auto WasPresent = Files.erase(File);
   (void)WasPresent;
   assert(WasPresent && "File was not tracked");
@@ -202,7 +202,7 @@ PrecompilePreambleAction::CreateASTConsumer(CompilerInstance &CI,
 
   std::unique_ptr<llvm::raw_ostream> OS;
   if (InMemStorage) {
-    OS = llvm::make_unique<llvm::raw_string_ostream>(*InMemStorage);
+    OS = std::make_unique<llvm::raw_string_ostream>(*InMemStorage);
   } else {
     std::string OutputFile;
     OS = GeneratePCHAction::CreateOutputFile(CI, InFile, OutputFile);
@@ -213,7 +213,7 @@ PrecompilePreambleAction::CreateASTConsumer(CompilerInstance &CI,
   if (!CI.getFrontendOpts().RelocatablePCH)
     Sysroot.clear();
 
-  return llvm::make_unique<PrecompilePreambleConsumer>(
+  return std::make_unique<PrecompilePreambleConsumer>(
       *this, CI.getPreprocessor(), CI.getModuleCache(), Sysroot, std::move(OS));
 }
 
@@ -303,7 +303,7 @@ llvm::ErrorOr<PrecompiledPreamble> PrecompiledPreamble::Build(
       Clang->getFrontendOpts().Inputs[0].getKind().getFormat() !=
           InputKind::Source ||
       Clang->getFrontendOpts().Inputs[0].getKind().getLanguage() ==
-          InputKind::LLVM_IR) {
+          Language::LLVM_IR) {
     return BuildPreambleError::BadInputs;
   }
 
@@ -369,9 +369,11 @@ llvm::ErrorOr<PrecompiledPreamble> PrecompiledPreamble::Build(
 
   SourceManager &SourceMgr = Clang->getSourceManager();
   for (auto &Filename : PreambleDepCollector->getDependencies()) {
-    const FileEntry *File = Clang->getFileManager().getFile(Filename);
-    if (!File || File == SourceMgr.getFileEntryForID(SourceMgr.getMainFileID()))
+    auto FileOrErr = Clang->getFileManager().getFile(Filename);
+    if (!FileOrErr ||
+        *FileOrErr == SourceMgr.getFileEntryForID(SourceMgr.getMainFileID()))
       continue;
+    auto File = *FileOrErr;
     if (time_t ModTime = File->getModificationTime()) {
       FilesInPreamble[File->getName()] =
           PrecompiledPreamble::PreambleFileHash::createForFile(File->getSize(),
diff --git a/lib/Frontend/PrintPreprocessedOutput.cpp b/lib/Frontend/PrintPreprocessedOutput.cpp
index 732edacffbe3d..24ea1ccba207f 100644
--- a/lib/Frontend/PrintPreprocessedOutput.cpp
+++ b/lib/Frontend/PrintPreprocessedOutput.cpp
@@ -675,7 +675,7 @@ struct UnknownPragmaHandler : public PragmaHandler {
     if (ShouldExpandTokens) {
       // The first token does not have expanded macros. Expand them, if
       // required.
-      auto Toks = llvm::make_unique<Token[]>(1);
+      auto Toks = std::make_unique<Token[]>(1);
       Toks[0] = PragmaTok;
       PP.EnterTokenStream(std::move(Toks), /*NumToks=*/1,
                           /*DisableMacroExpansion=*/false,
diff --git a/lib/Frontend/Rewrite/FixItRewriter.cpp b/lib/Frontend/Rewrite/FixItRewriter.cpp
index 667b9f0469f7e..0217b3385a518 100644
--- a/lib/Frontend/Rewrite/FixItRewriter.cpp
+++ b/lib/Frontend/Rewrite/FixItRewriter.cpp
@@ -101,7 +101,7 @@ bool FixItRewriter::WriteFixedFiles(
     if (fd != -1) {
       OS.reset(new llvm::raw_fd_ostream(fd, /*shouldClose=*/true));
     } else {
-      OS.reset(new llvm::raw_fd_ostream(Filename, EC, llvm::sys::fs::F_None));
+      OS.reset(new llvm::raw_fd_ostream(Filename, EC, llvm::sys::fs::OF_None));
     }
     if (EC) {
       Diags.Report(clang::diag::err_fe_unable_to_open_output) << Filename
diff --git a/lib/Frontend/Rewrite/FrontendActions.cpp b/lib/Frontend/Rewrite/FrontendActions.cpp
index 0f1a0584c72b5..549b86edebcd6 100644
--- a/lib/Frontend/Rewrite/FrontendActions.cpp
+++ b/lib/Frontend/Rewrite/FrontendActions.cpp
@@ -9,6 +9,7 @@
 #include "clang/Rewrite/Frontend/FrontendActions.h"
 #include "clang/AST/ASTConsumer.h"
 #include "clang/Basic/CharInfo.h"
+#include "clang/Basic/LangStandard.h"
 #include "clang/Config/config.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/FrontendActions.h"
@@ -49,7 +50,7 @@ FixItAction::~FixItAction() {}
 
 std::unique_ptr<ASTConsumer>
 FixItAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
-  return llvm::make_unique<ASTConsumer>();
+  return std::make_unique<ASTConsumer>();
 }
 
 namespace {
@@ -211,16 +212,16 @@ public:
 
   void visitModuleFile(StringRef Filename,
                        serialization::ModuleKind Kind) override {
-    auto *File = CI.getFileManager().getFile(Filename);
+    auto File = CI.getFileManager().getFile(Filename);
     assert(File && "missing file for loaded module?");
 
     // Only rewrite each module file once.
-    if (!Rewritten.insert(File).second)
+    if (!Rewritten.insert(*File).second)
       return;
 
     serialization::ModuleFile *MF =
-        CI.getModuleManager()->getModuleManager().lookup(File);
-    assert(File && "missing module file for loaded module?");
+        CI.getModuleManager()->getModuleManager().lookup(*File);
+    assert(MF && "missing module file for loaded module?");
 
     // Not interested in PCH / preambles.
     if (!MF->isModule())
@@ -250,7 +251,7 @@ public:
     Instance.getFrontendOpts().DisableFree = false;
     Instance.getFrontendOpts().Inputs.clear();
     Instance.getFrontendOpts().Inputs.emplace_back(
-        Filename, InputKind(InputKind::Unknown, InputKind::Precompiled));
+        Filename, InputKind(Language::Unknown, InputKind::Precompiled));
     Instance.getFrontendOpts().ModuleFiles.clear();
     Instance.getFrontendOpts().ModuleMapFiles.clear();
     // Don't recursively rewrite imports. We handle them all at the top level.
@@ -294,7 +295,7 @@ bool RewriteIncludesAction::BeginSourceFileAction(CompilerInstance &CI) {
   if (CI.getPreprocessorOutputOpts().RewriteImports) {
     CI.createModuleManager();
     CI.getModuleManager()->addListener(
-        llvm::make_unique<RewriteImportsListener>(CI, OutputStream));
+        std::make_unique<RewriteImportsListener>(CI, OutputStream));
   }
 
   return true;
diff --git a/lib/Frontend/Rewrite/HTMLPrint.cpp b/lib/Frontend/Rewrite/HTMLPrint.cpp
index a5b36bc7856cd..982e56cebbca0 100644
--- a/lib/Frontend/Rewrite/HTMLPrint.cpp
+++ b/lib/Frontend/Rewrite/HTMLPrint.cpp
@@ -48,7 +48,7 @@ namespace {
 std::unique_ptr<ASTConsumer>
 clang::CreateHTMLPrinter(std::unique_ptr<raw_ostream> OS, Preprocessor &PP,
                          bool SyntaxHighlight, bool HighlightMacros) {
-  return llvm::make_unique<HTMLPrinter>(std::move(OS), PP, SyntaxHighlight,
+  return std::make_unique<HTMLPrinter>(std::move(OS), PP, SyntaxHighlight,
                                         HighlightMacros);
 }
 
diff --git a/lib/Frontend/Rewrite/InclusionRewriter.cpp b/lib/Frontend/Rewrite/InclusionRewriter.cpp
index cb4e773aca87a..dcf645f67f2f3 100644
--- a/lib/Frontend/Rewrite/InclusionRewriter.cpp
+++ b/lib/Frontend/Rewrite/InclusionRewriter.cpp
@@ -49,6 +49,8 @@ class InclusionRewriter : public PPCallbacks {
   std::map<unsigned, const Module *> ModuleIncludes;
   /// Tracks where inclusions that enter modules (in a module build) are found.
   std::map<unsigned, const Module *> ModuleEntryIncludes;
+  /// Tracks where #if and #elif directives get evaluated and whether to true.
+  std::map<unsigned, bool> IfConditions;
   /// Used transitively for building up the FileIncludes mapping over the
   /// various \c PPCallbacks callbacks.
   SourceLocation LastInclusionLocation;
@@ -70,7 +72,7 @@ private:
   void FileChanged(SourceLocation Loc, FileChangeReason Reason,
                    SrcMgr::CharacteristicKind FileType,
                    FileID PrevFID) override;
-  void FileSkipped(const FileEntry &SkippedFile, const Token &FilenameTok,
+  void FileSkipped(const FileEntryRef &SkippedFile, const Token &FilenameTok,
                    SrcMgr::CharacteristicKind FileType) override;
   void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
                           StringRef FileName, bool IsAngled,
@@ -78,6 +80,10 @@ private:
                           StringRef SearchPath, StringRef RelativePath,
                           const Module *Imported,
                           SrcMgr::CharacteristicKind FileType) override;
+  void If(SourceLocation Loc, SourceRange ConditionRange,
+          ConditionValueKind ConditionValue) override;
+  void Elif(SourceLocation Loc, SourceRange ConditionRange,
+            ConditionValueKind ConditionValue, SourceLocation IfLoc) override;
   void WriteLineInfo(StringRef Filename, int Line,
                      SrcMgr::CharacteristicKind FileType,
                      StringRef Extra = StringRef());
@@ -89,12 +95,10 @@ private:
   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 IncludedFile *FindIncludeAtLocation(SourceLocation Loc) const;
   const Module *FindModuleAtLocation(SourceLocation Loc) const;
   const Module *FindEnteredModule(SourceLocation Loc) const;
+  bool IsIfAtLocationTrue(SourceLocation Loc) const;
   StringRef NextIdentifierName(Lexer &RawLex, Token &RawToken);
 };
 
@@ -169,8 +173,8 @@ void InclusionRewriter::FileChanged(SourceLocation Loc,
 
 /// Called whenever an inclusion is skipped due to canonical header protection
 /// macros.
-void InclusionRewriter::FileSkipped(const FileEntry &/*SkippedFile*/,
-                                    const Token &/*FilenameTok*/,
+void InclusionRewriter::FileSkipped(const FileEntryRef & /*SkippedFile*/,
+                                    const Token & /*FilenameTok*/,
                                     SrcMgr::CharacteristicKind /*FileType*/) {
   assert(LastInclusionLocation.isValid() &&
          "A file, that wasn't found via an inclusion directive, was skipped");
@@ -203,6 +207,23 @@ void InclusionRewriter::InclusionDirective(SourceLocation HashLoc,
     LastInclusionLocation = HashLoc;
 }
 
+void InclusionRewriter::If(SourceLocation Loc, SourceRange ConditionRange,
+                           ConditionValueKind ConditionValue) {
+  auto P = IfConditions.insert(
+      std::make_pair(Loc.getRawEncoding(), ConditionValue == CVK_True));
+  (void)P;
+  assert(P.second && "Unexpected revisitation of the same if directive");
+}
+
+void InclusionRewriter::Elif(SourceLocation Loc, SourceRange ConditionRange,
+                             ConditionValueKind ConditionValue,
+                             SourceLocation IfLoc) {
+  auto P = IfConditions.insert(
+      std::make_pair(Loc.getRawEncoding(), ConditionValue == CVK_True));
+  (void)P;
+  assert(P.second && "Unexpected revisitation of the same elif directive");
+}
+
 /// Simple lookup for a SourceLocation (specifically one denoting the hash in
 /// an inclusion directive) in the map of inclusion information, FileChanges.
 const InclusionRewriter::IncludedFile *
@@ -233,6 +254,13 @@ InclusionRewriter::FindEnteredModule(SourceLocation Loc) const {
   return nullptr;
 }
 
+bool InclusionRewriter::IsIfAtLocationTrue(SourceLocation Loc) const {
+  const auto I = IfConditions.find(Loc.getRawEncoding());
+  if (I != IfConditions.end())
+    return I->second;
+  return false;
+}
+
 /// Detect the likely line ending style of \p FromFile by examining the first
 /// newline found within it.
 static StringRef DetectEOL(const MemoryBuffer &FromFile) {
@@ -346,80 +374,6 @@ StringRef InclusionRewriter::NextIdentifierName(Lexer &RawLex,
   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 *FileEnt = PP.getSourceManager().getFileEntryForID(FileId);
-  SmallVector<std::pair<const FileEntry *, const DirectoryEntry *>, 1>
-      Includers;
-  Includers.push_back(std::make_pair(FileEnt, FileEnt->getDir()));
-  // FIXME: Why don't we call PP.LookupFile here?
-  const FileEntry *File = PP.getHeaderSearchInfo().LookupFile(
-      Filename, SourceLocation(), isAngled, Lookup, CurDir, Includers, nullptr,
-      nullptr, nullptr, nullptr, nullptr, nullptr);
-
-  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.
 void InclusionRewriter::Process(FileID FileId,
@@ -519,53 +473,33 @@ void InclusionRewriter::Process(FileID FileId,
           case tok::pp_elif: {
             bool elif = (RawToken.getIdentifierInfo()->getPPKeywordID() ==
                          tok::pp_elif);
-            // Rewrite special builtin macros to avoid pulling in host details.
+            bool isTrue = IsIfAtLocationTrue(RawToken.getLocation());
+            OutputContentUpTo(FromFile, NextToWrite,
+                              SM.getFileOffset(HashToken.getLocation()),
+                              LocalEOL, Line, /*EnsureNewline=*/true);
             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")) {
-                  if (DirLookup)
-                    ++DirLookup;
-
-                  if (!HandleHasInclude(FileId, RawLex, DirLookup, 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),
-                                  LocalEOL, Line, false);
-                OS << '(' << (int) HasFile << ")/*";
-                OutputContentUpTo(FromFile, NextToWrite,
-                                  SM.getFileOffset(RawToken.getLocation()) +
-                                      RawToken.getLength(),
-                                  LocalEOL, Line, false);
-                OS << "*/";
-              }
-            } while (RawToken.isNot(tok::eod));
+            } while (!RawToken.is(tok::eod) && RawToken.isNot(tok::eof));
+            // We need to disable the old condition, but that is tricky.
+            // Trying to comment it out can easily lead to comment nesting.
+            // So instead make the condition harmless by making it enclose
+            // and empty block. Moreover, put it itself inside an #if 0 block
+            // to disable it from getting evaluated (e.g. __has_include_next
+            // warns if used from the primary source file).
+            OS << "#if 0 /* disabled by -frewrite-includes */" << MainEOL;
             if (elif) {
-              OutputContentUpTo(FromFile, NextToWrite,
-                                SM.getFileOffset(RawToken.getLocation()) +
-                                    RawToken.getLength(),
-                                LocalEOL, Line, /*EnsureNewline=*/ true);
-              WriteLineInfo(FileName, Line, FileType);
+              OS << "#if 0" << MainEOL;
             }
+            OutputContentUpTo(FromFile, NextToWrite,
+                              SM.getFileOffset(RawToken.getLocation()) +
+                                  RawToken.getLength(),
+                              LocalEOL, Line, /*EnsureNewline=*/true);
+            // Close the empty block and the disabling block.
+            OS << "#endif" << MainEOL;
+            OS << "#endif /* disabled by -frewrite-includes */" << MainEOL;
+            OS << (elif ? "#elif " : "#if ") << (isTrue ? "1" : "0")
+               << " /* evaluated by -frewrite-includes */" << MainEOL;
+            WriteLineInfo(FileName, Line, FileType);
             break;
           }
           case tok::pp_endif:
diff --git a/lib/Frontend/Rewrite/RewriteModernObjC.cpp b/lib/Frontend/Rewrite/RewriteModernObjC.cpp
index bd091ee033512..45495065ada64 100644
--- a/lib/Frontend/Rewrite/RewriteModernObjC.cpp
+++ b/lib/Frontend/Rewrite/RewriteModernObjC.cpp
@@ -505,7 +505,7 @@ namespace {
     /// otherwise.
     bool convertBlockPointerToFunctionPointer(QualType &T) {
       if (isTopLevelBlockPointerType(T)) {
-        const BlockPointerType *BPT = T->getAs<BlockPointerType>();
+        const auto *BPT = T->castAs<BlockPointerType>();
         T = Context->getPointerType(BPT->getPointeeType());
         return true;
       }
@@ -597,8 +597,8 @@ namespace {
 
     StringLiteral *getStringLiteral(StringRef Str) {
       QualType StrType = Context->getConstantArrayType(
-          Context->CharTy, llvm::APInt(32, Str.size() + 1), ArrayType::Normal,
-          0);
+          Context->CharTy, llvm::APInt(32, Str.size() + 1), nullptr,
+          ArrayType::Normal, 0);
       return StringLiteral::Create(*Context, Str, StringLiteral::Ascii,
                                    /*Pascal=*/false, StrType, SourceLocation());
     }
@@ -663,7 +663,7 @@ std::unique_ptr<ASTConsumer> clang::CreateModernObjCRewriter(
     const std::string &InFile, std::unique_ptr<raw_ostream> OS,
     DiagnosticsEngine &Diags, const LangOptions &LOpts,
     bool SilenceRewriteMacroWarning, bool LineInfo) {
-  return llvm::make_unique<RewriteModernObjC>(InFile, std::move(OS), Diags,
+  return std::make_unique<RewriteModernObjC>(InFile, std::move(OS), Diags,
                                               LOpts, SilenceRewriteMacroWarning,
                                               LineInfo);
 }
@@ -852,12 +852,11 @@ RewriteModernObjC::getIvarAccessString(ObjCIvarDecl *D) {
     IvarT = GetGroupRecordTypeForObjCIvarBitfield(D);
 
   if (!isa<TypedefType>(IvarT) && IvarT->isRecordType()) {
-    RecordDecl *RD = IvarT->getAs<RecordType>()->getDecl();
+    RecordDecl *RD = IvarT->castAs<RecordType>()->getDecl();
     RD = RD->getDefinition();
     if (RD && !RD->getDeclName().getAsIdentifierInfo()) {
       // decltype(((Foo_IMPL*)0)->bar) *
-      ObjCContainerDecl *CDecl =
-      dyn_cast<ObjCContainerDecl>(D->getDeclContext());
+      auto *CDecl = cast<ObjCContainerDecl>(D->getDeclContext());
       // ivar in class extensions requires special treatment.
       if (ObjCCategoryDecl *CatDecl = dyn_cast<ObjCCategoryDecl>(CDecl))
         CDecl = CatDecl->getClassInterface();
@@ -1332,6 +1331,7 @@ void RewriteModernObjC::RewriteObjCMethodDecl(const ObjCInterfaceDecl *IDecl,
 void RewriteModernObjC::RewriteImplementationDecl(Decl *OID) {
   ObjCImplementationDecl *IMD = dyn_cast<ObjCImplementationDecl>(OID);
   ObjCCategoryImplDecl *CID = dyn_cast<ObjCCategoryImplDecl>(OID);
+  assert((IMD || CID) && "Unknown implementation type");
 
   if (IMD) {
     if (IMD->getIvarRBraceLoc().isValid()) {
@@ -2103,8 +2103,7 @@ RewriteModernObjC::SynthesizeCallToFunctionDecl(FunctionDecl *FD,
     ImplicitCastExpr::Create(*Context, pToFunc, CK_FunctionToPointerDecay,
                              DRE, nullptr, VK_RValue);
 
-  const FunctionType *FT = msgSendType->getAs<FunctionType>();
-
+  const auto *FT = msgSendType->castAs<FunctionType>();
   CallExpr *Exp = CallExpr::Create(
       *Context, ICE, Args, FT->getCallResultType(*Context), VK_RValue, EndLoc);
   return Exp;
@@ -2752,7 +2751,7 @@ Stmt *RewriteModernObjC::RewriteObjCArrayLiteralExpr(ObjCArrayLiteral *Exp) {
 
   // Create a call to objc_getClass("NSArray"). It will be th 1st argument.
   ObjCInterfaceDecl *Class =
-    expType->getPointeeType()->getAs<ObjCObjectType>()->getInterface();
+    expType->getPointeeType()->castAs<ObjCObjectType>()->getInterface();
 
   IdentifierInfo *clsName = Class->getIdentifier();
   ClsExprs.push_back(getStringLiteral(clsName->getName()));
@@ -2806,7 +2805,7 @@ Stmt *RewriteModernObjC::RewriteObjCArrayLiteralExpr(ObjCArrayLiteral *Exp) {
   // Don't forget the parens to enforce the proper binding.
   ParenExpr *PE = new (Context) ParenExpr(StartLoc, EndLoc, cast);
 
-  const FunctionType *FT = msgSendType->getAs<FunctionType>();
+  const FunctionType *FT = msgSendType->castAs<FunctionType>();
   CallExpr *CE = CallExpr::Create(*Context, PE, MsgExprs, FT->getReturnType(),
                                   VK_RValue, EndLoc);
   ReplaceStmt(Exp, CE);
@@ -2894,7 +2893,7 @@ Stmt *RewriteModernObjC::RewriteObjCDictionaryLiteralExpr(ObjCDictionaryLiteral
 
   // Create a call to objc_getClass("NSArray"). It will be th 1st argument.
   ObjCInterfaceDecl *Class =
-  expType->getPointeeType()->getAs<ObjCObjectType>()->getInterface();
+  expType->getPointeeType()->castAs<ObjCObjectType>()->getInterface();
 
   IdentifierInfo *clsName = Class->getIdentifier();
   ClsExprs.push_back(getStringLiteral(clsName->getName()));
@@ -2957,7 +2956,7 @@ Stmt *RewriteModernObjC::RewriteObjCDictionaryLiteralExpr(ObjCDictionaryLiteral
   // Don't forget the parens to enforce the proper binding.
   ParenExpr *PE = new (Context) ParenExpr(StartLoc, EndLoc, cast);
 
-  const FunctionType *FT = msgSendType->getAs<FunctionType>();
+  const FunctionType *FT = msgSendType->castAs<FunctionType>();
   CallExpr *CE = CallExpr::Create(*Context, PE, MsgExprs, FT->getReturnType(),
                                   VK_RValue, EndLoc);
   ReplaceStmt(Exp, CE);
@@ -3309,7 +3308,7 @@ Stmt *RewriteModernObjC::SynthMessageExpr(ObjCMessageExpr *Exp,
   case ObjCMessageExpr::Class: {
     SmallVector<Expr*, 8> ClsExprs;
     ObjCInterfaceDecl *Class
-      = Exp->getClassReceiver()->getAs<ObjCObjectType>()->getInterface();
+      = Exp->getClassReceiver()->castAs<ObjCObjectType>()->getInterface();
     IdentifierInfo *clsName = Class->getIdentifier();
     ClsExprs.push_back(getStringLiteral(clsName->getName()));
     CallExpr *Cls = SynthesizeCallToFunctionDecl(GetClassFunctionDecl, ClsExprs,
@@ -3530,7 +3529,7 @@ Stmt *RewriteModernObjC::SynthMessageExpr(ObjCMessageExpr *Exp,
   // Don't forget the parens to enforce the proper binding.
   ParenExpr *PE = new (Context) ParenExpr(StartLoc, EndLoc, cast);
 
-  const FunctionType *FT = msgSendType->getAs<FunctionType>();
+  const FunctionType *FT = msgSendType->castAs<FunctionType>();
   CallExpr *CE = CallExpr::Create(*Context, PE, MsgExprs, FT->getReturnType(),
                                   VK_RValue, EndLoc);
   Stmt *ReplacingStmt = CE;
@@ -3637,7 +3636,7 @@ bool RewriteModernObjC::RewriteObjCFieldDeclType(QualType &Type,
     return RewriteObjCFieldDeclType(ElemTy, Result);
   }
   else if (Type->isRecordType()) {
-    RecordDecl *RD = Type->getAs<RecordType>()->getDecl();
+    RecordDecl *RD = Type->castAs<RecordType>()->getDecl();
     if (RD->isCompleteDefinition()) {
       if (RD->isStruct())
         Result += "\n\tstruct ";
@@ -3660,7 +3659,7 @@ bool RewriteModernObjC::RewriteObjCFieldDeclType(QualType &Type,
     }
   }
   else if (Type->isEnumeralType()) {
-    EnumDecl *ED = Type->getAs<EnumType>()->getDecl();
+    EnumDecl *ED = Type->castAs<EnumType>()->getDecl();
     if (ED->isCompleteDefinition()) {
       Result += "\n\tenum ";
       Result += ED->getName();
@@ -3727,15 +3726,15 @@ void RewriteModernObjC::RewriteLocallyDefinedNamedAggregates(FieldDecl *fieldDec
     return;
   if (Type->isArrayType())
     Type = Context->getBaseElementType(Type);
-  ObjCContainerDecl *IDecl =
-    dyn_cast<ObjCContainerDecl>(fieldDecl->getDeclContext());
+
+  auto *IDecl = dyn_cast<ObjCContainerDecl>(fieldDecl->getDeclContext());
 
   TagDecl *TD = nullptr;
   if (Type->isRecordType()) {
-    TD = Type->getAs<RecordType>()->getDecl();
+    TD = Type->castAs<RecordType>()->getDecl();
   }
   else if (Type->isEnumeralType()) {
-    TD = Type->getAs<EnumType>()->getDecl();
+    TD = Type->castAs<EnumType>()->getDecl();
   }
 
   if (TD) {
@@ -5753,7 +5752,7 @@ void RewriteModernObjC::HandleDeclInMainFile(Decl *D) {
           }
         }
       } else if (VD->getType()->isRecordType()) {
-        RecordDecl *RD = VD->getType()->getAs<RecordType>()->getDecl();
+        RecordDecl *RD = VD->getType()->castAs<RecordType>()->getDecl();
         if (RD->isCompleteDefinition())
           RewriteRecordBody(RD);
       }
@@ -7494,7 +7493,7 @@ Stmt *RewriteModernObjC::RewriteObjCIvarRefExpr(ObjCIvarRefExpr *IV) {
         IvarT = GetGroupRecordTypeForObjCIvarBitfield(D);
 
       if (!isa<TypedefType>(IvarT) && IvarT->isRecordType()) {
-        RecordDecl *RD = IvarT->getAs<RecordType>()->getDecl();
+        RecordDecl *RD = IvarT->castAs<RecordType>()->getDecl();
         RD = RD->getDefinition();
         if (RD && !RD->getDeclName().getAsIdentifierInfo()) {
           // decltype(((Foo_IMPL*)0)->bar) *
diff --git a/lib/Frontend/Rewrite/RewriteObjC.cpp b/lib/Frontend/Rewrite/RewriteObjC.cpp
index 05078baee790c..6a22da178fbc9 100644
--- a/lib/Frontend/Rewrite/RewriteObjC.cpp
+++ b/lib/Frontend/Rewrite/RewriteObjC.cpp
@@ -416,7 +416,7 @@ namespace {
     /// otherwise.
     bool convertBlockPointerToFunctionPointer(QualType &T) {
       if (isTopLevelBlockPointerType(T)) {
-        const BlockPointerType *BPT = T->getAs<BlockPointerType>();
+        const auto *BPT = T->castAs<BlockPointerType>();
         T = Context->getPointerType(BPT->getPointeeType());
         return true;
       }
@@ -497,8 +497,8 @@ namespace {
 
     StringLiteral *getStringLiteral(StringRef Str) {
       QualType StrType = Context->getConstantArrayType(
-          Context->CharTy, llvm::APInt(32, Str.size() + 1), ArrayType::Normal,
-          0);
+          Context->CharTy, llvm::APInt(32, Str.size() + 1), nullptr,
+          ArrayType::Normal, 0);
       return StringLiteral::Create(*Context, Str, StringLiteral::Ascii,
                                    /*Pascal=*/false, StrType, SourceLocation());
     }
@@ -593,7 +593,7 @@ clang::CreateObjCRewriter(const std::string &InFile,
                           std::unique_ptr<raw_ostream> OS,
                           DiagnosticsEngine &Diags, const LangOptions &LOpts,
                           bool SilenceRewriteMacroWarning) {
-  return llvm::make_unique<RewriteObjCFragileABI>(
+  return std::make_unique<RewriteObjCFragileABI>(
       InFile, std::move(OS), Diags, LOpts, SilenceRewriteMacroWarning);
 }
 
@@ -1163,6 +1163,7 @@ void RewriteObjC::RewriteObjCMethodDecl(const ObjCInterfaceDecl *IDecl,
 void RewriteObjC::RewriteImplementationDecl(Decl *OID) {
   ObjCImplementationDecl *IMD = dyn_cast<ObjCImplementationDecl>(OID);
   ObjCCategoryImplDecl *CID = dyn_cast<ObjCCategoryImplDecl>(OID);
+  assert((IMD || CID) && "Unknown ImplementationDecl");
 
   InsertText(IMD ? IMD->getBeginLoc() : CID->getBeginLoc(), "// ");
 
@@ -2017,7 +2018,7 @@ RewriteObjC::SynthesizeCallToFunctionDecl(FunctionDecl *FD,
     ImplicitCastExpr::Create(*Context, pToFunc, CK_FunctionToPointerDecay,
                              DRE, nullptr, VK_RValue);
 
-  const FunctionType *FT = msgSendType->getAs<FunctionType>();
+  const auto *FT = msgSendType->castAs<FunctionType>();
 
   CallExpr *Exp = CallExpr::Create(
       *Context, ICE, Args, FT->getCallResultType(*Context), VK_RValue, EndLoc);
@@ -2285,7 +2286,7 @@ void RewriteObjC::RewriteBlockPointerTypeVariable(std::string& Str,
 void RewriteObjC::RewriteBlockLiteralFunctionDecl(FunctionDecl *FD) {
   SourceLocation FunLocStart = FD->getTypeSpecStartLoc();
   const FunctionType *funcType = FD->getType()->getAs<FunctionType>();
-  const FunctionProtoType *proto = dyn_cast<FunctionProtoType>(funcType);
+  const FunctionProtoType *proto = dyn_cast_or_null<FunctionProtoType>(funcType);
   if (!proto)
     return;
   QualType Type = proto->getReturnType();
@@ -2604,7 +2605,7 @@ CallExpr *RewriteObjC::SynthMsgSendStretCallExpr(FunctionDecl *MsgSendStretFlavo
   // Don't forget the parens to enforce the proper binding.
   ParenExpr *PE = new (Context) ParenExpr(SourceLocation(), SourceLocation(), cast);
 
-  const FunctionType *FT = msgSendType->getAs<FunctionType>();
+  const auto *FT = msgSendType->castAs<FunctionType>();
   CallExpr *STCE = CallExpr::Create(*Context, PE, MsgExprs, FT->getReturnType(),
                                     VK_RValue, SourceLocation());
   return STCE;
@@ -2735,8 +2736,8 @@ Stmt *RewriteObjC::SynthMessageExpr(ObjCMessageExpr *Exp,
 
   case ObjCMessageExpr::Class: {
     SmallVector<Expr*, 8> ClsExprs;
-    ObjCInterfaceDecl *Class
-      = Exp->getClassReceiver()->getAs<ObjCObjectType>()->getInterface();
+    auto *Class =
+        Exp->getClassReceiver()->castAs<ObjCObjectType>()->getInterface();
     IdentifierInfo *clsName = Class->getIdentifier();
     ClsExprs.push_back(getStringLiteral(clsName->getName()));
     CallExpr *Cls = SynthesizeCallToFunctionDecl(GetClassFunctionDecl, ClsExprs,
@@ -2957,7 +2958,7 @@ Stmt *RewriteObjC::SynthMessageExpr(ObjCMessageExpr *Exp,
   // Don't forget the parens to enforce the proper binding.
   ParenExpr *PE = new (Context) ParenExpr(StartLoc, EndLoc, cast);
 
-  const FunctionType *FT = msgSendType->getAs<FunctionType>();
+  const auto *FT = msgSendType->castAs<FunctionType>();
   CallExpr *CE = CallExpr::Create(*Context, PE, MsgExprs, FT->getReturnType(),
                                   VK_RValue, EndLoc);
   Stmt *ReplacingStmt = CE;
@@ -4849,7 +4850,7 @@ void RewriteObjC::HandleDeclInMainFile(Decl *D) {
           }
         }
       } else if (VD->getType()->isRecordType()) {
-        RecordDecl *RD = VD->getType()->getAs<RecordType>()->getDecl();
+        RecordDecl *RD = VD->getType()->castAs<RecordType>()->getDecl();
         if (RD->isCompleteDefinition())
           RewriteRecordBody(RD);
       }
diff --git a/lib/Frontend/SerializedDiagnosticPrinter.cpp b/lib/Frontend/SerializedDiagnosticPrinter.cpp
index c1434a95cc709..8042b52ddc032 100644
--- a/lib/Frontend/SerializedDiagnosticPrinter.cpp
+++ b/lib/Frontend/SerializedDiagnosticPrinter.cpp
@@ -296,7 +296,7 @@ namespace clang {
 namespace serialized_diags {
 std::unique_ptr<DiagnosticConsumer>
 create(StringRef OutputFile, DiagnosticOptions *Diags, bool MergeChildRecords) {
-  return llvm::make_unique<SDiagsWriter>(OutputFile, Diags, MergeChildRecords);
+  return std::make_unique<SDiagsWriter>(OutputFile, Diags, MergeChildRecords);
 }
 
 } // end namespace serialized_diags
@@ -743,7 +743,7 @@ DiagnosticsEngine *SDiagsWriter::getMetaDiags() {
     IntrusiveRefCntPtr<DiagnosticIDs> IDs(new DiagnosticIDs());
     auto Client =
         new TextDiagnosticPrinter(llvm::errs(), State->DiagOpts.get());
-    State->MetaDiagnostics = llvm::make_unique<DiagnosticsEngine>(
+    State->MetaDiagnostics = std::make_unique<DiagnosticsEngine>(
         IDs, State->DiagOpts.get(), Client);
   }
   return State->MetaDiagnostics.get();
@@ -780,8 +780,8 @@ void SDiagsWriter::finish() {
   }
 
   std::error_code EC;
-  auto OS = llvm::make_unique<llvm::raw_fd_ostream>(State->OutputFile.c_str(),
-                                                    EC, llvm::sys::fs::F_None);
+  auto OS = std::make_unique<llvm::raw_fd_ostream>(State->OutputFile.c_str(),
+                                                    EC, llvm::sys::fs::OF_None);
   if (EC) {
     getMetaDiags()->Report(diag::warn_fe_serialized_diag_failure)
         << State->OutputFile << EC.message();
diff --git a/lib/Frontend/TextDiagnostic.cpp b/lib/Frontend/TextDiagnostic.cpp
index d0c91286250e7..7bb6c5b74d5f6 100644
--- a/lib/Frontend/TextDiagnostic.cpp
+++ b/lib/Frontend/TextDiagnostic.cpp
@@ -683,8 +683,9 @@ void TextDiagnostic::emitDiagnosticMessage(
   if (DiagOpts->ShowColors)
     OS.resetColor();
 
-  printDiagnosticLevel(OS, Level, DiagOpts->ShowColors,
-                       DiagOpts->CLFallbackMode);
+  if (DiagOpts->ShowLevel)
+    printDiagnosticLevel(OS, Level, DiagOpts->ShowColors,
+                         DiagOpts->CLFallbackMode);
   printDiagnosticMessage(OS,
                          /*IsSupplemental*/ Level == DiagnosticsEngine::Note,
                          Message, OS.tell() - StartOfLocationInfo,
@@ -762,7 +763,7 @@ void TextDiagnostic::printDiagnosticMessage(raw_ostream &OS,
 void TextDiagnostic::emitFilename(StringRef Filename, const SourceManager &SM) {
   SmallVector<char, 128> AbsoluteFilename;
   if (DiagOpts->AbsolutePath) {
-    const DirectoryEntry *Dir = SM.getFileManager().getDirectory(
+    auto Dir = SM.getFileManager().getDirectory(
         llvm::sys::path::parent_path(Filename));
     if (Dir) {
       // We want to print a simplified absolute path, i. e. without "dots".
@@ -780,12 +781,12 @@ void TextDiagnostic::emitFilename(StringRef Filename, const SourceManager &SM) {
       // on Windows we can just use llvm::sys::path::remove_dots(), because,
       // on that system, both aforementioned paths point to the same place.
 #ifdef _WIN32
-      SmallString<4096> DirName = Dir->getName();
+      SmallString<4096> DirName = (*Dir)->getName();
       llvm::sys::fs::make_absolute(DirName);
       llvm::sys::path::native(DirName);
       llvm::sys::path::remove_dots(DirName, /* remove_dot_dot */ true);
 #else
-      StringRef DirName = SM.getFileManager().getCanonicalName(Dir);
+      StringRef DirName = SM.getFileManager().getCanonicalName(*Dir);
 #endif
       llvm::sys::path::append(AbsoluteFilename, DirName,
                               llvm::sys::path::filename(Filename));
diff --git a/lib/Frontend/VerifyDiagnosticConsumer.cpp b/lib/Frontend/VerifyDiagnosticConsumer.cpp
index a68ef03d4db14..82c2af87706eb 100644
--- a/lib/Frontend/VerifyDiagnosticConsumer.cpp
+++ b/lib/Frontend/VerifyDiagnosticConsumer.cpp
@@ -528,15 +528,16 @@ static bool ParseDirective(StringRef S, ExpectedData *ED, SourceManager &SM,
 
         // Lookup file via Preprocessor, like a #include.
         const DirectoryLookup *CurDir;
-        const FileEntry *FE =
+        Optional<FileEntryRef> File =
             PP->LookupFile(Pos, Filename, false, nullptr, nullptr, CurDir,
                            nullptr, nullptr, nullptr, nullptr, nullptr);
-        if (!FE) {
+        if (!File) {
           Diags.Report(Pos.getLocWithOffset(PH.C-PH.Begin),
                        diag::err_verify_missing_file) << Filename << KindStr;
           continue;
         }
 
+        const FileEntry *FE = &File->getFileEntry();
         if (SM.translateFile(FE).isInvalid())
           SM.createFileID(FE, Pos, SrcMgr::C_User);
 
@@ -671,7 +672,7 @@ void VerifyDiagnosticConsumer::BeginSourceFile(const LangOptions &LangOpts,
 #ifndef NDEBUG
       // Debug build tracks parsed files.
       const_cast<Preprocessor *>(PP)->addPPCallbacks(
-                      llvm::make_unique<VerifyFileTracker>(*this, *SrcManager));
+                      std::make_unique<VerifyFileTracker>(*this, *SrcManager));
 #endif
     }
   }
@@ -1116,7 +1117,7 @@ std::unique_ptr<Directive> Directive::create(bool RegexKind,
                                              bool MatchAnyLine, StringRef Text,
                                              unsigned Min, unsigned Max) {
   if (!RegexKind)
-    return llvm::make_unique<StandardDirective>(DirectiveLoc, DiagnosticLoc,
+    return std::make_unique<StandardDirective>(DirectiveLoc, DiagnosticLoc,
                                                 MatchAnyLine, Text, Min, Max);
 
   // Parse the directive into a regular expression.
@@ -1142,6 +1143,6 @@ std::unique_ptr<Directive> Directive::create(bool RegexKind,
     }
   }
 
-  return llvm::make_unique<RegexDirective>(
+  return std::make_unique<RegexDirective>(
       DirectiveLoc, DiagnosticLoc, MatchAnyLine, Text, Min, Max, RegexStr);
 }