vendor/clang/clang-release_39-r276489

4 files changed, 551 insertions, 26 deletions

diff --git a/lib/Tooling/Core/CMakeLists.txt b/lib/Tooling/Core/CMakeLists.txt
index b88e1f8333a2..f6348cbf80ed 100644
--- a/lib/Tooling/Core/CMakeLists.txt
+++ b/lib/Tooling/Core/CMakeLists.txt
@@ -3,6 +3,7 @@ set(LLVM_LINK_COMPONENTS support)
 add_clang_library(clangToolingCore
   Lookup.cpp
   Replacement.cpp
+  QualTypeNames.cpp
 
   LINK_LIBS
   clangAST
diff --git a/lib/Tooling/Core/Makefile b/lib/Tooling/Core/Makefile
deleted file mode 100644
index 366466c192e4..000000000000
--- a/lib/Tooling/Core/Makefile
+++ /dev/null
@@ -1,13 +0,0 @@
-##===- clang/lib/Tooling/Core/Makefile ---------------------*- Makefile -*-===##
-#
-#                     The LLVM Compiler Infrastructure
-#
-# This file is distributed under the University of Illinois Open Source
-# License. See LICENSE.TXT for details.
-#
-##===----------------------------------------------------------------------===##
-
-CLANG_LEVEL := ../../..
-LIBRARYNAME := clangToolingCore
-
-include $(CLANG_LEVEL)/Makefile
diff --git a/lib/Tooling/Core/QualTypeNames.cpp b/lib/Tooling/Core/QualTypeNames.cpp
new file mode 100644
index 000000000000..619dae1ee106
--- /dev/null
+++ b/lib/Tooling/Core/QualTypeNames.cpp
@@ -0,0 +1,479 @@
+//===------- QualTypeNames.cpp - Generate Complete QualType Names ---------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Tooling/Core/QualTypeNames.h"
+#include "clang/AST/DeclTemplate.h"
+#include "clang/AST/DeclarationName.h"
+#include "clang/AST/GlobalDecl.h"
+#include "clang/AST/Mangle.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/StringRef.h"
+
+#include <stdio.h>
+#include <memory>
+
+namespace clang {
+
+namespace TypeName {
+/// \brief Generates a QualType that can be used to name the same type
+/// if used at the end of the current translation unit. This ignores
+/// issues such as type shadowing.
+///
+/// \param[in] QT - the type for which the fully qualified type will be
+/// returned.
+/// \param[in] Ctx - the ASTContext to be used.
+/// \param[in] WithGlobalNsPrefix - Indicate whether the global namespace
+/// specifier "::" should be prepended or not.
+static QualType getFullyQualifiedType(QualType QT, const ASTContext &Ctx,
+                                      bool WithGlobalNsPrefix);
+
+/// \brief Create a NestedNameSpecifier for Namesp and its enclosing
+/// scopes.
+///
+/// \param[in] Ctx - the AST Context to be used.
+/// \param[in] Namesp - the NamespaceDecl for which a NestedNameSpecifier
+/// is requested.
+/// \param[in] WithGlobalNsPrefix - Indicate whether the global namespace
+/// specifier "::" should be prepended or not.
+static NestedNameSpecifier *createNestedNameSpecifier(
+    const ASTContext &Ctx,
+    const NamespaceDecl *Namesp,
+    bool WithGlobalNsPrefix);
+
+/// \brief Create a NestedNameSpecifier for TagDecl and its enclosing
+/// scopes.
+///
+/// \param[in] Ctx - the AST Context to be used.
+/// \param[in] TD - the TagDecl for which a NestedNameSpecifier is
+/// requested.
+/// \param[in] FullyQualify - Convert all template arguments into fully
+/// qualified names.
+/// \param[in] WithGlobalNsPrefix - Indicate whether the global namespace
+/// specifier "::" should be prepended or not.
+static NestedNameSpecifier *createNestedNameSpecifier(
+    const ASTContext &Ctx, const TypeDecl *TD,
+    bool FullyQualify, bool WithGlobalNsPrefix);
+
+static NestedNameSpecifier *createNestedNameSpecifierForScopeOf(
+    const ASTContext &Ctx, const Decl *decl,
+    bool FullyQualified, bool WithGlobalNsPrefix);
+
+static NestedNameSpecifier *getFullyQualifiedNestedNameSpecifier(
+    const ASTContext &Ctx, NestedNameSpecifier *scope, bool WithGlobalNsPrefix);
+
+static bool getFullyQualifiedTemplateName(const ASTContext &Ctx,
+                                          TemplateName &TName,
+                                          bool WithGlobalNsPrefix) {
+  bool Changed = false;
+  NestedNameSpecifier *NNS = nullptr;
+
+  TemplateDecl *ArgTDecl = TName.getAsTemplateDecl();
+  // ArgTDecl won't be NULL because we asserted that this isn't a
+  // dependent context very early in the call chain.
+  assert(ArgTDecl != nullptr);
+  QualifiedTemplateName *QTName = TName.getAsQualifiedTemplateName();
+
+  if (QTName && !QTName->hasTemplateKeyword()) {
+    NNS = QTName->getQualifier();
+    NestedNameSpecifier *QNNS = getFullyQualifiedNestedNameSpecifier(
+        Ctx, NNS, WithGlobalNsPrefix);
+    if (QNNS != NNS) {
+      Changed = true;
+      NNS = QNNS;
+    } else {
+      NNS = nullptr;
+    }
+  } else {
+    NNS = createNestedNameSpecifierForScopeOf(
+        Ctx, ArgTDecl, true, WithGlobalNsPrefix);
+  }
+  if (NNS) {
+    TName = Ctx.getQualifiedTemplateName(NNS,
+                                         /*TemplateKeyword=*/false, ArgTDecl);
+    Changed = true;
+  }
+  return Changed;
+}
+
+static bool getFullyQualifiedTemplateArgument(const ASTContext &Ctx,
+                                              TemplateArgument &Arg,
+                                              bool WithGlobalNsPrefix) {
+  bool Changed = false;
+
+  // Note: we do not handle TemplateArgument::Expression, to replace it
+  // we need the information for the template instance decl.
+
+  if (Arg.getKind() == TemplateArgument::Template) {
+    TemplateName TName = Arg.getAsTemplate();
+    Changed = getFullyQualifiedTemplateName(Ctx, TName, WithGlobalNsPrefix);
+    if (Changed) {
+      Arg = TemplateArgument(TName);
+    }
+  } else if (Arg.getKind() == TemplateArgument::Type) {
+    QualType SubTy = Arg.getAsType();
+    // Check if the type needs more desugaring and recurse.
+    QualType QTFQ = getFullyQualifiedType(SubTy, Ctx, WithGlobalNsPrefix);
+    if (QTFQ != SubTy) {
+      Arg = TemplateArgument(QTFQ);
+      Changed = true;
+    }
+  }
+  return Changed;
+}
+
+static const Type *getFullyQualifiedTemplateType(const ASTContext &Ctx,
+                                                 const Type *TypePtr,
+                                                 bool WithGlobalNsPrefix) {
+  // DependentTemplateTypes exist within template declarations and
+  // definitions. Therefore we shouldn't encounter them at the end of
+  // a translation unit. If we do, the caller has made an error.
+  assert(!isa<DependentTemplateSpecializationType>(TypePtr));
+  // In case of template specializations, iterate over the arguments
+  // and fully qualify them as well.
+  if (const auto *TST = dyn_cast<const TemplateSpecializationType>(TypePtr)) {
+    bool MightHaveChanged = false;
+    SmallVector<TemplateArgument, 4> FQArgs;
+    for (TemplateSpecializationType::iterator I = TST->begin(), E = TST->end();
+         I != E; ++I) {
+      // Cheap to copy and potentially modified by
+      // getFullyQualifedTemplateArgument.
+      TemplateArgument Arg(*I);
+      MightHaveChanged |= getFullyQualifiedTemplateArgument(
+          Ctx, Arg, WithGlobalNsPrefix);
+      FQArgs.push_back(Arg);
+    }
+
+    // If a fully qualified arg is different from the unqualified arg,
+    // allocate new type in the AST.
+    if (MightHaveChanged) {
+      QualType QT = Ctx.getTemplateSpecializationType(
+          TST->getTemplateName(), FQArgs,
+          TST->getCanonicalTypeInternal());
+      // getTemplateSpecializationType returns a fully qualified
+      // version of the specialization itself, so no need to qualify
+      // it.
+      return QT.getTypePtr();
+    }
+  } else if (const auto *TSTRecord = dyn_cast<const RecordType>(TypePtr)) {
+    // We are asked to fully qualify and we have a Record Type,
+    // which can point to a template instantiation with no sugar in any of
+    // its template argument, however we still need to fully qualify them.
+
+    if (const auto *TSTDecl =
+        dyn_cast<ClassTemplateSpecializationDecl>(TSTRecord->getDecl())) {
+      const TemplateArgumentList &TemplateArgs = TSTDecl->getTemplateArgs();
+
+      bool MightHaveChanged = false;
+      SmallVector<TemplateArgument, 4> FQArgs;
+      for (unsigned int I = 0, E = TemplateArgs.size(); I != E; ++I) {
+        // cheap to copy and potentially modified by
+        // getFullyQualifedTemplateArgument
+        TemplateArgument Arg(TemplateArgs[I]);
+        MightHaveChanged |= getFullyQualifiedTemplateArgument(
+            Ctx, Arg, WithGlobalNsPrefix);
+        FQArgs.push_back(Arg);
+      }
+
+      // If a fully qualified arg is different from the unqualified arg,
+      // allocate new type in the AST.
+      if (MightHaveChanged) {
+        TemplateName TN(TSTDecl->getSpecializedTemplate());
+        QualType QT = Ctx.getTemplateSpecializationType(
+            TN, FQArgs,
+            TSTRecord->getCanonicalTypeInternal());
+        // getTemplateSpecializationType returns a fully qualified
+        // version of the specialization itself, so no need to qualify
+        // it.
+        return QT.getTypePtr();
+      }
+    }
+  }
+  return TypePtr;
+}
+
+static NestedNameSpecifier *createOuterNNS(const ASTContext &Ctx, const Decl *D,
+                                           bool FullyQualify,
+                                           bool WithGlobalNsPrefix) {
+  const DeclContext *DC = D->getDeclContext();
+  if (const auto *NS = dyn_cast<NamespaceDecl>(DC)) {
+    while (NS && NS->isInline()) {
+      // Ignore inline namespace;
+      NS = dyn_cast<NamespaceDecl>(NS->getDeclContext());
+    }
+    if (NS->getDeclName()) {
+      return createNestedNameSpecifier(Ctx, NS, WithGlobalNsPrefix);
+    }
+    return nullptr;  // no starting '::', no anonymous
+  } else if (const auto *TD = dyn_cast<TagDecl>(DC)) {
+    return createNestedNameSpecifier(Ctx, TD, FullyQualify, WithGlobalNsPrefix);
+  } else if (const auto *TDD = dyn_cast<TypedefNameDecl>(DC)) {
+    return createNestedNameSpecifier(
+        Ctx, TDD, FullyQualify, WithGlobalNsPrefix);
+  } else if (WithGlobalNsPrefix && DC->isTranslationUnit()) {
+    return NestedNameSpecifier::GlobalSpecifier(Ctx);
+  }
+  return nullptr;  // no starting '::' if |WithGlobalNsPrefix| is false
+}
+
+/// \brief Return a fully qualified version of this name specifier.
+static NestedNameSpecifier *getFullyQualifiedNestedNameSpecifier(
+    const ASTContext &Ctx, NestedNameSpecifier *Scope,
+    bool WithGlobalNsPrefix) {
+  switch (Scope->getKind()) {
+    case NestedNameSpecifier::Global:
+      // Already fully qualified
+      return Scope;
+    case NestedNameSpecifier::Namespace:
+      return TypeName::createNestedNameSpecifier(
+          Ctx, Scope->getAsNamespace(), WithGlobalNsPrefix);
+    case NestedNameSpecifier::NamespaceAlias:
+      // Namespace aliases are only valid for the duration of the
+      // scope where they were introduced, and therefore are often
+      // invalid at the end of the TU.  So use the namespace name more
+      // likely to be valid at the end of the TU.
+      return TypeName::createNestedNameSpecifier(
+          Ctx,
+          Scope->getAsNamespaceAlias()->getNamespace()->getCanonicalDecl(),
+          WithGlobalNsPrefix);
+    case NestedNameSpecifier::Identifier:
+      // A function or some other construct that makes it un-namable
+      // at the end of the TU. Skip the current component of the name,
+      // but use the name of it's prefix.
+      return getFullyQualifiedNestedNameSpecifier(
+          Ctx, Scope->getPrefix(), WithGlobalNsPrefix);
+    case NestedNameSpecifier::Super:
+    case NestedNameSpecifier::TypeSpec:
+    case NestedNameSpecifier::TypeSpecWithTemplate: {
+      const Type *Type = Scope->getAsType();
+      // Find decl context.
+      const TagDecl *TD = nullptr;
+      if (const TagType *TagDeclType = Type->getAs<TagType>()) {
+        TD = TagDeclType->getDecl();
+      } else {
+        TD = Type->getAsCXXRecordDecl();
+      }
+      if (TD) {
+        return TypeName::createNestedNameSpecifier(Ctx, TD,
+                                                   true /*FullyQualified*/,
+                                                   WithGlobalNsPrefix);
+      } else if (const auto *TDD = dyn_cast<TypedefType>(Type)) {
+        return TypeName::createNestedNameSpecifier(Ctx, TDD->getDecl(),
+                                                   true /*FullyQualified*/,
+                                                   WithGlobalNsPrefix);
+      }
+      return Scope;
+    }
+  }
+  llvm_unreachable("bad NNS kind");
+}
+
+/// \brief Create a nested name specifier for the declaring context of
+/// the type.
+static NestedNameSpecifier *createNestedNameSpecifierForScopeOf(
+    const ASTContext &Ctx, const Decl *Decl,
+    bool FullyQualified, bool WithGlobalNsPrefix) {
+  assert(Decl);
+
+  const DeclContext *DC = Decl->getDeclContext()->getRedeclContext();
+  const auto *Outer = dyn_cast_or_null<NamedDecl>(DC);
+  const auto *OuterNS = dyn_cast_or_null<NamespaceDecl>(DC);
+  if (Outer && !(OuterNS && OuterNS->isAnonymousNamespace())) {
+    if (const auto *CxxDecl = dyn_cast<CXXRecordDecl>(DC)) {
+      if (ClassTemplateDecl *ClassTempl =
+              CxxDecl->getDescribedClassTemplate()) {
+        // We are in the case of a type(def) that was declared in a
+        // class template but is *not* type dependent.  In clang, it
+        // gets attached to the class template declaration rather than
+        // any specific class template instantiation.  This result in
+        // 'odd' fully qualified typename:
+        //
+        //    vector<_Tp,_Alloc>::size_type
+        //
+        // Make the situation is 'useable' but looking a bit odd by
+        // picking a random instance as the declaring context.
+        if (ClassTempl->spec_begin() != ClassTempl->spec_end()) {
+          Decl = *(ClassTempl->spec_begin());
+          Outer = dyn_cast<NamedDecl>(Decl);
+          OuterNS = dyn_cast<NamespaceDecl>(Decl);
+        }
+      }
+    }
+
+    if (OuterNS) {
+      return createNestedNameSpecifier(Ctx, OuterNS, WithGlobalNsPrefix);
+    } else if (const auto *TD = dyn_cast<TagDecl>(Outer)) {
+      return createNestedNameSpecifier(
+          Ctx, TD, FullyQualified, WithGlobalNsPrefix);
+    } else if (dyn_cast<TranslationUnitDecl>(Outer)) {
+      // Context is the TU. Nothing needs to be done.
+      return nullptr;
+    } else {
+      // Decl's context was neither the TU, a namespace, nor a
+      // TagDecl, which means it is a type local to a scope, and not
+      // accessible at the end of the TU.
+      return nullptr;
+    }
+  } else if (WithGlobalNsPrefix && DC->isTranslationUnit()) {
+    return NestedNameSpecifier::GlobalSpecifier(Ctx);
+  }
+  return nullptr;
+}
+
+/// \brief Create a nested name specifier for the declaring context of
+/// the type.
+static NestedNameSpecifier *createNestedNameSpecifierForScopeOf(
+    const ASTContext &Ctx, const Type *TypePtr,
+    bool FullyQualified, bool WithGlobalNsPrefix) {
+  if (!TypePtr) return nullptr;
+
+  Decl *Decl = nullptr;
+  // There are probably other cases ...
+  if (const auto *TDT = dyn_cast<TypedefType>(TypePtr)) {
+    Decl = TDT->getDecl();
+  } else if (const auto *TagDeclType = dyn_cast<TagType>(TypePtr)) {
+    Decl = TagDeclType->getDecl();
+  } else if (const auto *TST = dyn_cast<TemplateSpecializationType>(TypePtr)) {
+    Decl = TST->getTemplateName().getAsTemplateDecl();
+  } else {
+    Decl = TypePtr->getAsCXXRecordDecl();
+  }
+
+  if (!Decl) return nullptr;
+
+  return createNestedNameSpecifierForScopeOf(
+      Ctx, Decl, FullyQualified, WithGlobalNsPrefix);
+}
+
+NestedNameSpecifier *createNestedNameSpecifier(const ASTContext &Ctx,
+                                               const NamespaceDecl *Namespace,
+                                               bool WithGlobalNsPrefix) {
+  while (Namespace && Namespace->isInline()) {
+    // Ignore inline namespace;
+    Namespace = dyn_cast<NamespaceDecl>(Namespace->getDeclContext());
+  }
+  if (!Namespace) return nullptr;
+
+  bool FullyQualified = true;  // doesn't matter, DeclContexts are namespaces
+  return NestedNameSpecifier::Create(
+      Ctx,
+      createOuterNNS(Ctx, Namespace, FullyQualified, WithGlobalNsPrefix),
+      Namespace);
+}
+
+NestedNameSpecifier *createNestedNameSpecifier(const ASTContext &Ctx,
+                                               const TypeDecl *TD,
+                                               bool FullyQualify,
+                                               bool WithGlobalNsPrefix) {
+  return NestedNameSpecifier::Create(
+      Ctx,
+      createOuterNNS(Ctx, TD, FullyQualify, WithGlobalNsPrefix),
+      false /*No TemplateKeyword*/,
+      TD->getTypeForDecl());
+}
+
+/// \brief Return the fully qualified type, including fully-qualified
+/// versions of any template parameters.
+QualType getFullyQualifiedType(QualType QT, const ASTContext &Ctx,
+                               bool WithGlobalNsPrefix) {
+  // In case of myType* we need to strip the pointer first, fully
+  // qualify and attach the pointer once again.
+  if (isa<PointerType>(QT.getTypePtr())) {
+    // Get the qualifiers.
+    Qualifiers Quals = QT.getQualifiers();
+    QT = getFullyQualifiedType(QT->getPointeeType(), Ctx, WithGlobalNsPrefix);
+    QT = Ctx.getPointerType(QT);
+    // Add back the qualifiers.
+    QT = Ctx.getQualifiedType(QT, Quals);
+    return QT;
+  }
+
+  // In case of myType& we need to strip the reference first, fully
+  // qualify and attach the reference once again.
+  if (isa<ReferenceType>(QT.getTypePtr())) {
+    // Get the qualifiers.
+    bool IsLValueRefTy = isa<LValueReferenceType>(QT.getTypePtr());
+    Qualifiers Quals = QT.getQualifiers();
+    QT = getFullyQualifiedType(QT->getPointeeType(), Ctx, WithGlobalNsPrefix);
+    // Add the r- or l-value reference type back to the fully
+    // qualified one.
+    if (IsLValueRefTy)
+      QT = Ctx.getLValueReferenceType(QT);
+    else
+      QT = Ctx.getRValueReferenceType(QT);
+    // Add back the qualifiers.
+    QT = Ctx.getQualifiedType(QT, Quals);
+    return QT;
+  }
+
+  // Remove the part of the type related to the type being a template
+  // parameter (we won't report it as part of the 'type name' and it
+  // is actually make the code below to be more complex (to handle
+  // those)
+  while (isa<SubstTemplateTypeParmType>(QT.getTypePtr())) {
+    // Get the qualifiers.
+    Qualifiers Quals = QT.getQualifiers();
+
+    QT = dyn_cast<SubstTemplateTypeParmType>(QT.getTypePtr())->desugar();
+
+    // Add back the qualifiers.
+    QT = Ctx.getQualifiedType(QT, Quals);
+  }
+
+  NestedNameSpecifier *Prefix = nullptr;
+  // Local qualifiers are attached to the QualType outside of the
+  // elaborated type.  Retrieve them before descending into the
+  // elaborated type.
+  Qualifiers PrefixQualifiers = QT.getLocalQualifiers();
+  QT = QualType(QT.getTypePtr(), 0);
+  ElaboratedTypeKeyword Keyword = ETK_None;
+  if (const auto *ETypeInput = dyn_cast<ElaboratedType>(QT.getTypePtr())) {
+    QT = ETypeInput->getNamedType();
+    assert(!QT.hasLocalQualifiers());
+    Keyword = ETypeInput->getKeyword();
+  }
+  // Create a nested name specifier if needed.
+  Prefix = createNestedNameSpecifierForScopeOf(Ctx, QT.getTypePtr(),
+                                               true /*FullyQualified*/,
+                                               WithGlobalNsPrefix);
+
+  // In case of template specializations iterate over the arguments and
+  // fully qualify them as well.
+  if (isa<const TemplateSpecializationType>(QT.getTypePtr()) ||
+      isa<const RecordType>(QT.getTypePtr())) {
+    // We are asked to fully qualify and we have a Record Type (which
+    // may point to a template specialization) or Template
+    // Specialization Type. We need to fully qualify their arguments.
+
+    const Type *TypePtr = getFullyQualifiedTemplateType(
+        Ctx, QT.getTypePtr(), WithGlobalNsPrefix);
+    QT = QualType(TypePtr, 0);
+  }
+  if (Prefix || Keyword != ETK_None) {
+    QT = Ctx.getElaboratedType(Keyword, Prefix, QT);
+  }
+  QT = Ctx.getQualifiedType(QT, PrefixQualifiers);
+  return QT;
+}
+
+std::string getFullyQualifiedName(QualType QT,
+                                  const ASTContext &Ctx,
+                                  bool WithGlobalNsPrefix) {
+  PrintingPolicy Policy(Ctx.getPrintingPolicy());
+  Policy.SuppressScope = false;
+  Policy.AnonymousTagLocations = false;
+  Policy.PolishForDeclaration = true;
+  Policy.SuppressUnwrittenScope = true;
+  QualType FQQT = getFullyQualifiedType(QT, Ctx, WithGlobalNsPrefix);
+  return FQQT.getAsString(Policy);
+}
+
+}  // end namespace TypeName
+}  // end namespace clang
diff --git a/lib/Tooling/Core/Replacement.cpp b/lib/Tooling/Core/Replacement.cpp
index 47bbdeb470ee..4f130709ac16 100644
--- a/lib/Tooling/Core/Replacement.cpp
+++ b/lib/Tooling/Core/Replacement.cpp
@@ -11,6 +11,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "clang/Tooling/Core/Replacement.h"
+
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/DiagnosticIDs.h"
 #include "clang/Basic/DiagnosticOptions.h"
@@ -18,7 +20,6 @@
 #include "clang/Basic/SourceManager.h"
 #include "clang/Lex/Lexer.h"
 #include "clang/Rewrite/Core/Rewriter.h"
-#include "clang/Tooling/Core/Replacement.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/raw_os_ostream.h"
@@ -57,14 +58,8 @@ bool Replacement::apply(Rewriter &Rewrite) const {
   const FileEntry *Entry = SM.getFileManager().getFile(FilePath);
   if (!Entry)
     return false;
-  FileID ID;
-  // FIXME: Use SM.translateFile directly.
-  SourceLocation Location = SM.translateFileLineCol(Entry, 1, 1);
-  ID = Location.isValid() ?
-    SM.getFileID(Location) :
-    SM.createFileID(Entry, SourceLocation(), SrcMgr::C_User);
-  // FIXME: We cannot check whether Offset + Length is in the file, as
-  // the remapping API is not public in the RewriteBuffer.
+
+  FileID ID = SM.getOrCreateFileID(Entry, SrcMgr::C_User);
   const SourceLocation Start =
     SM.getLocForStartOfFile(ID).
     getLocWithOffset(ReplacementRange.getOffset());
@@ -254,7 +249,11 @@ bool applyAllReplacements(const std::vector<Replacement> &Replaces,
   return Result;
 }
 
-std::string applyAllReplacements(StringRef Code, const Replacements &Replaces) {
+llvm::Expected<std::string> applyAllReplacements(StringRef Code,
+                                                const Replacements &Replaces) {
+  if (Replaces.empty())
+    return Code.str();
+
   IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
       new vfs::InMemoryFileSystem);
   FileManager Files(FileSystemOptions(), InMemoryFileSystem);
@@ -272,7 +271,9 @@ std::string applyAllReplacements(StringRef Code, const Replacements &Replaces) {
     Replacement Replace("<stdin>", I->getOffset(), I->getLength(),
                         I->getReplacementText());
     if (!Replace.apply(Rewrite))
-      return "";
+      return llvm::make_error<llvm::StringError>(
+          "Failed to apply replacement: " + Replace.toString(),
+          llvm::inconvertibleErrorCode());
   }
   std::string Result;
   llvm::raw_string_ostream OS(Result);
@@ -281,6 +282,55 @@ std::string applyAllReplacements(StringRef Code, const Replacements &Replaces) {
   return Result;
 }
 
+// Merge and sort overlapping ranges in \p Ranges.
+static std::vector<Range> mergeAndSortRanges(std::vector<Range> Ranges) {
+  std::sort(Ranges.begin(), Ranges.end(),
+            [](const Range &LHS, const Range &RHS) {
+              if (LHS.getOffset() != RHS.getOffset())
+                return LHS.getOffset() < RHS.getOffset();
+              return LHS.getLength() < RHS.getLength();
+            });
+  std::vector<Range> Result;
+  for (const auto &R : Ranges) {
+    if (Result.empty() ||
+        Result.back().getOffset() + Result.back().getLength() < R.getOffset()) {
+      Result.push_back(R);
+    } else {
+      unsigned NewEnd =
+          std::max(Result.back().getOffset() + Result.back().getLength(),
+                   R.getOffset() + R.getLength());
+      Result[Result.size() - 1] =
+          Range(Result.back().getOffset(), NewEnd - Result.back().getOffset());
+    }
+  }
+  return Result;
+}
+
+std::vector<Range> calculateChangedRanges(const Replacements &Replaces) {
+  std::vector<Range> ChangedRanges;
+  int Shift = 0;
+  for (const Replacement &R : Replaces) {
+    unsigned Offset = R.getOffset() + Shift;
+    unsigned Length = R.getReplacementText().size();
+    Shift += Length - R.getLength();
+    ChangedRanges.push_back(Range(Offset, Length));
+  }
+  return mergeAndSortRanges(ChangedRanges);
+}
+
+std::vector<Range>
+calculateRangesAfterReplacements(const Replacements &Replaces,
+                                 const std::vector<Range> &Ranges) {
+  auto MergedRanges = mergeAndSortRanges(Ranges);
+  tooling::Replacements FakeReplaces;
+  for (const auto &R : MergedRanges)
+    FakeReplaces.insert(Replacement(Replaces.begin()->getFilePath(),
+                                    R.getOffset(), R.getLength(),
+                                    std::string(R.getLength(), ' ')));
+  tooling::Replacements NewReplaces = mergeReplacements(FakeReplaces, Replaces);
+  return calculateChangedRanges(NewReplaces);
+}
+
 namespace {
 // Represents a merged replacement, i.e. a replacement consisting of multiple
 // overlapping replacements from 'First' and 'Second' in mergeReplacements.
@@ -314,7 +364,7 @@ public:
 
   // Merges the next element 'R' into this merged element. As we always merge
   // from 'First' into 'Second' or vice versa, the MergedReplacement knows what
-  // set the next element is coming from. 
+  // set the next element is coming from.
   void merge(const Replacement &R) {
     if (MergeSecond) {
       unsigned REnd = R.getOffset() + Delta + R.getLength();
@@ -377,6 +427,15 @@ private:
 };
 } // namespace
 
+std::map<std::string, Replacements>
+groupReplacementsByFile(const Replacements &Replaces) {
+  std::map<std::string, Replacements> FileToReplaces;
+  for (const auto &Replace : Replaces) {
+    FileToReplaces[Replace.getFilePath()].insert(Replace);
+  }
+  return FileToReplaces;
+}
+
 Replacements mergeReplacements(const Replacements &First,
                                const Replacements &Second) {
   if (First.empty() || Second.empty())
@@ -416,4 +475,3 @@ Replacements mergeReplacements(const Replacements &First,
 
 } // end namespace tooling
 } // end namespace clang
-