diff clang/lib/AST/MicrosoftMangle.cpp @ 150:1d019706d866

LLVM10
author anatofuz
date Thu, 13 Feb 2020 15:10:13 +0900
parents
children e8a9b4f4d755 0572611fdcc8
line wrap: on
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/lib/AST/MicrosoftMangle.cpp	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,3543 @@
+//===--- MicrosoftMangle.cpp - Microsoft Visual C++ Name Mangling ---------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This provides C++ name mangling targeting the Microsoft Visual C++ ABI.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/AST/Mangle.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Attr.h"
+#include "clang/AST/CXXInheritance.h"
+#include "clang/AST/CharUnits.h"
+#include "clang/AST/Decl.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/DeclObjC.h"
+#include "clang/AST/DeclOpenMP.h"
+#include "clang/AST/DeclTemplate.h"
+#include "clang/AST/Expr.h"
+#include "clang/AST/ExprCXX.h"
+#include "clang/AST/VTableBuilder.h"
+#include "clang/Basic/ABI.h"
+#include "clang/Basic/DiagnosticOptions.h"
+#include "clang/Basic/TargetInfo.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/CRC.h"
+#include "llvm/Support/MD5.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/StringSaver.h"
+#include "llvm/Support/xxhash.h"
+
+using namespace clang;
+
+namespace {
+
+struct msvc_hashing_ostream : public llvm::raw_svector_ostream {
+  raw_ostream &OS;
+  llvm::SmallString<64> Buffer;
+
+  msvc_hashing_ostream(raw_ostream &OS)
+      : llvm::raw_svector_ostream(Buffer), OS(OS) {}
+  ~msvc_hashing_ostream() override {
+    StringRef MangledName = str();
+    bool StartsWithEscape = MangledName.startswith("\01");
+    if (StartsWithEscape)
+      MangledName = MangledName.drop_front(1);
+    if (MangledName.size() <= 4096) {
+      OS << str();
+      return;
+    }
+
+    llvm::MD5 Hasher;
+    llvm::MD5::MD5Result Hash;
+    Hasher.update(MangledName);
+    Hasher.final(Hash);
+
+    SmallString<32> HexString;
+    llvm::MD5::stringifyResult(Hash, HexString);
+
+    if (StartsWithEscape)
+      OS << '\01';
+    OS << "??@" << HexString << '@';
+  }
+};
+
+static const DeclContext *
+getLambdaDefaultArgumentDeclContext(const Decl *D) {
+  if (const auto *RD = dyn_cast<CXXRecordDecl>(D))
+    if (RD->isLambda())
+      if (const auto *Parm =
+              dyn_cast_or_null<ParmVarDecl>(RD->getLambdaContextDecl()))
+        return Parm->getDeclContext();
+  return nullptr;
+}
+
+/// Retrieve the declaration context that should be used when mangling
+/// the given declaration.
+static const DeclContext *getEffectiveDeclContext(const Decl *D) {
+  // The ABI assumes that lambda closure types that occur within
+  // default arguments live in the context of the function. However, due to
+  // the way in which Clang parses and creates function declarations, this is
+  // not the case: the lambda closure type ends up living in the context
+  // where the function itself resides, because the function declaration itself
+  // had not yet been created. Fix the context here.
+  if (const auto *LDADC = getLambdaDefaultArgumentDeclContext(D))
+    return LDADC;
+
+  // Perform the same check for block literals.
+  if (const BlockDecl *BD = dyn_cast<BlockDecl>(D)) {
+    if (ParmVarDecl *ContextParam =
+            dyn_cast_or_null<ParmVarDecl>(BD->getBlockManglingContextDecl()))
+      return ContextParam->getDeclContext();
+  }
+
+  const DeclContext *DC = D->getDeclContext();
+  if (isa<CapturedDecl>(DC) || isa<OMPDeclareReductionDecl>(DC) ||
+      isa<OMPDeclareMapperDecl>(DC)) {
+    return getEffectiveDeclContext(cast<Decl>(DC));
+  }
+
+  return DC->getRedeclContext();
+}
+
+static const DeclContext *getEffectiveParentContext(const DeclContext *DC) {
+  return getEffectiveDeclContext(cast<Decl>(DC));
+}
+
+static const FunctionDecl *getStructor(const NamedDecl *ND) {
+  if (const auto *FTD = dyn_cast<FunctionTemplateDecl>(ND))
+    return FTD->getTemplatedDecl()->getCanonicalDecl();
+
+  const auto *FD = cast<FunctionDecl>(ND);
+  if (const auto *FTD = FD->getPrimaryTemplate())
+    return FTD->getTemplatedDecl()->getCanonicalDecl();
+
+  return FD->getCanonicalDecl();
+}
+
+/// MicrosoftMangleContextImpl - Overrides the default MangleContext for the
+/// Microsoft Visual C++ ABI.
+class MicrosoftMangleContextImpl : public MicrosoftMangleContext {
+  typedef std::pair<const DeclContext *, IdentifierInfo *> DiscriminatorKeyTy;
+  llvm::DenseMap<DiscriminatorKeyTy, unsigned> Discriminator;
+  llvm::DenseMap<const NamedDecl *, unsigned> Uniquifier;
+  llvm::DenseMap<const CXXRecordDecl *, unsigned> LambdaIds;
+  llvm::DenseMap<const NamedDecl *, unsigned> SEHFilterIds;
+  llvm::DenseMap<const NamedDecl *, unsigned> SEHFinallyIds;
+  SmallString<16> AnonymousNamespaceHash;
+
+public:
+  MicrosoftMangleContextImpl(ASTContext &Context, DiagnosticsEngine &Diags);
+  bool shouldMangleCXXName(const NamedDecl *D) override;
+  bool shouldMangleStringLiteral(const StringLiteral *SL) override;
+  void mangleCXXName(const NamedDecl *D, raw_ostream &Out) override;
+  void mangleVirtualMemPtrThunk(const CXXMethodDecl *MD,
+                                const MethodVFTableLocation &ML,
+                                raw_ostream &Out) override;
+  void mangleThunk(const CXXMethodDecl *MD, const ThunkInfo &Thunk,
+                   raw_ostream &) override;
+  void mangleCXXDtorThunk(const CXXDestructorDecl *DD, CXXDtorType Type,
+                          const ThisAdjustment &ThisAdjustment,
+                          raw_ostream &) override;
+  void mangleCXXVFTable(const CXXRecordDecl *Derived,
+                        ArrayRef<const CXXRecordDecl *> BasePath,
+                        raw_ostream &Out) override;
+  void mangleCXXVBTable(const CXXRecordDecl *Derived,
+                        ArrayRef<const CXXRecordDecl *> BasePath,
+                        raw_ostream &Out) override;
+  void mangleCXXVirtualDisplacementMap(const CXXRecordDecl *SrcRD,
+                                       const CXXRecordDecl *DstRD,
+                                       raw_ostream &Out) override;
+  void mangleCXXThrowInfo(QualType T, bool IsConst, bool IsVolatile,
+                          bool IsUnaligned, uint32_t NumEntries,
+                          raw_ostream &Out) override;
+  void mangleCXXCatchableTypeArray(QualType T, uint32_t NumEntries,
+                                   raw_ostream &Out) override;
+  void mangleCXXCatchableType(QualType T, const CXXConstructorDecl *CD,
+                              CXXCtorType CT, uint32_t Size, uint32_t NVOffset,
+                              int32_t VBPtrOffset, uint32_t VBIndex,
+                              raw_ostream &Out) override;
+  void mangleCXXRTTI(QualType T, raw_ostream &Out) override;
+  void mangleCXXRTTIName(QualType T, raw_ostream &Out) override;
+  void mangleCXXRTTIBaseClassDescriptor(const CXXRecordDecl *Derived,
+                                        uint32_t NVOffset, int32_t VBPtrOffset,
+                                        uint32_t VBTableOffset, uint32_t Flags,
+                                        raw_ostream &Out) override;
+  void mangleCXXRTTIBaseClassArray(const CXXRecordDecl *Derived,
+                                   raw_ostream &Out) override;
+  void mangleCXXRTTIClassHierarchyDescriptor(const CXXRecordDecl *Derived,
+                                             raw_ostream &Out) override;
+  void
+  mangleCXXRTTICompleteObjectLocator(const CXXRecordDecl *Derived,
+                                     ArrayRef<const CXXRecordDecl *> BasePath,
+                                     raw_ostream &Out) override;
+  void mangleTypeName(QualType T, raw_ostream &) override;
+  void mangleCXXCtor(const CXXConstructorDecl *D, CXXCtorType Type,
+                     raw_ostream &) override;
+  void mangleCXXDtor(const CXXDestructorDecl *D, CXXDtorType Type,
+                     raw_ostream &) override;
+  void mangleReferenceTemporary(const VarDecl *, unsigned ManglingNumber,
+                                raw_ostream &) override;
+  void mangleStaticGuardVariable(const VarDecl *D, raw_ostream &Out) override;
+  void mangleThreadSafeStaticGuardVariable(const VarDecl *D, unsigned GuardNum,
+                                           raw_ostream &Out) override;
+  void mangleDynamicInitializer(const VarDecl *D, raw_ostream &Out) override;
+  void mangleDynamicAtExitDestructor(const VarDecl *D,
+                                     raw_ostream &Out) override;
+  void mangleSEHFilterExpression(const NamedDecl *EnclosingDecl,
+                                 raw_ostream &Out) override;
+  void mangleSEHFinallyBlock(const NamedDecl *EnclosingDecl,
+                             raw_ostream &Out) override;
+  void mangleStringLiteral(const StringLiteral *SL, raw_ostream &Out) override;
+  bool getNextDiscriminator(const NamedDecl *ND, unsigned &disc) {
+    const DeclContext *DC = getEffectiveDeclContext(ND);
+    if (!DC->isFunctionOrMethod())
+      return false;
+
+    // Lambda closure types are already numbered, give out a phony number so
+    // that they demangle nicely.
+    if (const auto *RD = dyn_cast<CXXRecordDecl>(ND)) {
+      if (RD->isLambda()) {
+        disc = 1;
+        return true;
+      }
+    }
+
+    // Use the canonical number for externally visible decls.
+    if (ND->isExternallyVisible()) {
+      disc = getASTContext().getManglingNumber(ND);
+      return true;
+    }
+
+    // Anonymous tags are already numbered.
+    if (const TagDecl *Tag = dyn_cast<TagDecl>(ND)) {
+      if (!Tag->hasNameForLinkage() &&
+          !getASTContext().getDeclaratorForUnnamedTagDecl(Tag) &&
+          !getASTContext().getTypedefNameForUnnamedTagDecl(Tag))
+        return false;
+    }
+
+    // Make up a reasonable number for internal decls.
+    unsigned &discriminator = Uniquifier[ND];
+    if (!discriminator)
+      discriminator = ++Discriminator[std::make_pair(DC, ND->getIdentifier())];
+    disc = discriminator + 1;
+    return true;
+  }
+
+  unsigned getLambdaId(const CXXRecordDecl *RD) {
+    assert(RD->isLambda() && "RD must be a lambda!");
+    assert(!RD->isExternallyVisible() && "RD must not be visible!");
+    assert(RD->getLambdaManglingNumber() == 0 &&
+           "RD must not have a mangling number!");
+    std::pair<llvm::DenseMap<const CXXRecordDecl *, unsigned>::iterator, bool>
+        Result = LambdaIds.insert(std::make_pair(RD, LambdaIds.size()));
+    return Result.first->second;
+  }
+
+  /// Return a character sequence that is (somewhat) unique to the TU suitable
+  /// for mangling anonymous namespaces.
+  StringRef getAnonymousNamespaceHash() const {
+    return AnonymousNamespaceHash;
+  }
+
+private:
+  void mangleInitFiniStub(const VarDecl *D, char CharCode, raw_ostream &Out);
+};
+
+/// MicrosoftCXXNameMangler - Manage the mangling of a single name for the
+/// Microsoft Visual C++ ABI.
+class MicrosoftCXXNameMangler {
+  MicrosoftMangleContextImpl &Context;
+  raw_ostream &Out;
+
+  /// The "structor" is the top-level declaration being mangled, if
+  /// that's not a template specialization; otherwise it's the pattern
+  /// for that specialization.
+  const NamedDecl *Structor;
+  unsigned StructorType;
+
+  typedef llvm::SmallVector<std::string, 10> BackRefVec;
+  BackRefVec NameBackReferences;
+
+  typedef llvm::DenseMap<const void *, unsigned> ArgBackRefMap;
+  ArgBackRefMap FunArgBackReferences;
+  ArgBackRefMap TemplateArgBackReferences;
+
+  typedef llvm::DenseMap<const void *, StringRef> TemplateArgStringMap;
+  TemplateArgStringMap TemplateArgStrings;
+  llvm::StringSaver TemplateArgStringStorage;
+  llvm::BumpPtrAllocator TemplateArgStringStorageAlloc;
+
+  typedef std::set<std::pair<int, bool>> PassObjectSizeArgsSet;
+  PassObjectSizeArgsSet PassObjectSizeArgs;
+
+  ASTContext &getASTContext() const { return Context.getASTContext(); }
+
+  const bool PointersAre64Bit;
+
+public:
+  enum QualifierMangleMode { QMM_Drop, QMM_Mangle, QMM_Escape, QMM_Result };
+
+  MicrosoftCXXNameMangler(MicrosoftMangleContextImpl &C, raw_ostream &Out_)
+      : Context(C), Out(Out_), Structor(nullptr), StructorType(-1),
+        TemplateArgStringStorage(TemplateArgStringStorageAlloc),
+        PointersAre64Bit(C.getASTContext().getTargetInfo().getPointerWidth(0) ==
+                         64) {}
+
+  MicrosoftCXXNameMangler(MicrosoftMangleContextImpl &C, raw_ostream &Out_,
+                          const CXXConstructorDecl *D, CXXCtorType Type)
+      : Context(C), Out(Out_), Structor(getStructor(D)), StructorType(Type),
+        TemplateArgStringStorage(TemplateArgStringStorageAlloc),
+        PointersAre64Bit(C.getASTContext().getTargetInfo().getPointerWidth(0) ==
+                         64) {}
+
+  MicrosoftCXXNameMangler(MicrosoftMangleContextImpl &C, raw_ostream &Out_,
+                          const CXXDestructorDecl *D, CXXDtorType Type)
+      : Context(C), Out(Out_), Structor(getStructor(D)), StructorType(Type),
+        TemplateArgStringStorage(TemplateArgStringStorageAlloc),
+        PointersAre64Bit(C.getASTContext().getTargetInfo().getPointerWidth(0) ==
+                         64) {}
+
+  raw_ostream &getStream() const { return Out; }
+
+  void mangle(const NamedDecl *D, StringRef Prefix = "?");
+  void mangleName(const NamedDecl *ND);
+  void mangleFunctionEncoding(const FunctionDecl *FD, bool ShouldMangle);
+  void mangleVariableEncoding(const VarDecl *VD);
+  void mangleMemberDataPointer(const CXXRecordDecl *RD, const ValueDecl *VD);
+  void mangleMemberFunctionPointer(const CXXRecordDecl *RD,
+                                   const CXXMethodDecl *MD);
+  void mangleVirtualMemPtrThunk(const CXXMethodDecl *MD,
+                                const MethodVFTableLocation &ML);
+  void mangleNumber(int64_t Number);
+  void mangleTagTypeKind(TagTypeKind TK);
+  void mangleArtificialTagType(TagTypeKind TK, StringRef UnqualifiedName,
+                              ArrayRef<StringRef> NestedNames = None);
+  void mangleAddressSpaceType(QualType T, Qualifiers Quals, SourceRange Range);
+  void mangleType(QualType T, SourceRange Range,
+                  QualifierMangleMode QMM = QMM_Mangle);
+  void mangleFunctionType(const FunctionType *T,
+                          const FunctionDecl *D = nullptr,
+                          bool ForceThisQuals = false,
+                          bool MangleExceptionSpec = true);
+  void mangleNestedName(const NamedDecl *ND);
+
+private:
+  bool isStructorDecl(const NamedDecl *ND) const {
+    return ND == Structor || getStructor(ND) == Structor;
+  }
+
+  bool is64BitPointer(Qualifiers Quals) const {
+    LangAS AddrSpace = Quals.getAddressSpace();
+    return AddrSpace == LangAS::ptr64 ||
+           (PointersAre64Bit && !(AddrSpace == LangAS::ptr32_sptr ||
+                                  AddrSpace == LangAS::ptr32_uptr));
+  }
+
+  void mangleUnqualifiedName(const NamedDecl *ND) {
+    mangleUnqualifiedName(ND, ND->getDeclName());
+  }
+  void mangleUnqualifiedName(const NamedDecl *ND, DeclarationName Name);
+  void mangleSourceName(StringRef Name);
+  void mangleOperatorName(OverloadedOperatorKind OO, SourceLocation Loc);
+  void mangleCXXDtorType(CXXDtorType T);
+  void mangleQualifiers(Qualifiers Quals, bool IsMember);
+  void mangleRefQualifier(RefQualifierKind RefQualifier);
+  void manglePointerCVQualifiers(Qualifiers Quals);
+  void manglePointerExtQualifiers(Qualifiers Quals, QualType PointeeType);
+
+  void mangleUnscopedTemplateName(const TemplateDecl *ND);
+  void
+  mangleTemplateInstantiationName(const TemplateDecl *TD,
+                                  const TemplateArgumentList &TemplateArgs);
+  void mangleObjCMethodName(const ObjCMethodDecl *MD);
+
+  void mangleFunctionArgumentType(QualType T, SourceRange Range);
+  void manglePassObjectSizeArg(const PassObjectSizeAttr *POSA);
+
+  bool isArtificialTagType(QualType T) const;
+
+  // Declare manglers for every type class.
+#define ABSTRACT_TYPE(CLASS, PARENT)
+#define NON_CANONICAL_TYPE(CLASS, PARENT)
+#define TYPE(CLASS, PARENT) void mangleType(const CLASS##Type *T, \
+                                            Qualifiers Quals, \
+                                            SourceRange Range);
+#include "clang/AST/TypeNodes.inc"
+#undef ABSTRACT_TYPE
+#undef NON_CANONICAL_TYPE
+#undef TYPE
+
+  void mangleType(const TagDecl *TD);
+  void mangleDecayedArrayType(const ArrayType *T);
+  void mangleArrayType(const ArrayType *T);
+  void mangleFunctionClass(const FunctionDecl *FD);
+  void mangleCallingConvention(CallingConv CC);
+  void mangleCallingConvention(const FunctionType *T);
+  void mangleIntegerLiteral(const llvm::APSInt &Number, bool IsBoolean);
+  void mangleExpression(const Expr *E);
+  void mangleThrowSpecification(const FunctionProtoType *T);
+
+  void mangleTemplateArgs(const TemplateDecl *TD,
+                          const TemplateArgumentList &TemplateArgs);
+  void mangleTemplateArg(const TemplateDecl *TD, const TemplateArgument &TA,
+                         const NamedDecl *Parm);
+
+  void mangleObjCProtocol(const ObjCProtocolDecl *PD);
+  void mangleObjCLifetime(const QualType T, Qualifiers Quals,
+                          SourceRange Range);
+  void mangleObjCKindOfType(const ObjCObjectType *T, Qualifiers Quals,
+                            SourceRange Range);
+};
+}
+
+MicrosoftMangleContextImpl::MicrosoftMangleContextImpl(ASTContext &Context,
+                                                       DiagnosticsEngine &Diags)
+    : MicrosoftMangleContext(Context, Diags) {
+  // To mangle anonymous namespaces, hash the path to the main source file. The
+  // path should be whatever (probably relative) path was passed on the command
+  // line. The goal is for the compiler to produce the same output regardless of
+  // working directory, so use the uncanonicalized relative path.
+  //
+  // It's important to make the mangled names unique because, when CodeView
+  // debug info is in use, the debugger uses mangled type names to distinguish
+  // between otherwise identically named types in anonymous namespaces.
+  //
+  // These symbols are always internal, so there is no need for the hash to
+  // match what MSVC produces. For the same reason, clang is free to change the
+  // hash at any time without breaking compatibility with old versions of clang.
+  // The generated names are intended to look similar to what MSVC generates,
+  // which are something like "?A0x01234567@".
+  SourceManager &SM = Context.getSourceManager();
+  if (const FileEntry *FE = SM.getFileEntryForID(SM.getMainFileID())) {
+    // Truncate the hash so we get 8 characters of hexadecimal.
+    uint32_t TruncatedHash = uint32_t(xxHash64(FE->getName()));
+    AnonymousNamespaceHash = llvm::utohexstr(TruncatedHash);
+  } else {
+    // If we don't have a path to the main file, we'll just use 0.
+    AnonymousNamespaceHash = "0";
+  }
+}
+
+bool MicrosoftMangleContextImpl::shouldMangleCXXName(const NamedDecl *D) {
+  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
+    LanguageLinkage L = FD->getLanguageLinkage();
+    // Overloadable functions need mangling.
+    if (FD->hasAttr<OverloadableAttr>())
+      return true;
+
+    // The ABI expects that we would never mangle "typical" user-defined entry
+    // points regardless of visibility or freestanding-ness.
+    //
+    // N.B. This is distinct from asking about "main".  "main" has a lot of
+    // special rules associated with it in the standard while these
+    // user-defined entry points are outside of the purview of the standard.
+    // For example, there can be only one definition for "main" in a standards
+    // compliant program; however nothing forbids the existence of wmain and
+    // WinMain in the same translation unit.
+    if (FD->isMSVCRTEntryPoint())
+      return false;
+
+    // C++ functions and those whose names are not a simple identifier need
+    // mangling.
+    if (!FD->getDeclName().isIdentifier() || L == CXXLanguageLinkage)
+      return true;
+
+    // C functions are not mangled.
+    if (L == CLanguageLinkage)
+      return false;
+  }
+
+  // Otherwise, no mangling is done outside C++ mode.
+  if (!getASTContext().getLangOpts().CPlusPlus)
+    return false;
+
+  const VarDecl *VD = dyn_cast<VarDecl>(D);
+  if (VD && !isa<DecompositionDecl>(D)) {
+    // C variables are not mangled.
+    if (VD->isExternC())
+      return false;
+
+    // Variables at global scope with non-internal linkage are not mangled.
+    const DeclContext *DC = getEffectiveDeclContext(D);
+    // Check for extern variable declared locally.
+    if (DC->isFunctionOrMethod() && D->hasLinkage())
+      while (!DC->isNamespace() && !DC->isTranslationUnit())
+        DC = getEffectiveParentContext(DC);
+
+    if (DC->isTranslationUnit() && D->getFormalLinkage() == InternalLinkage &&
+        !isa<VarTemplateSpecializationDecl>(D) &&
+        D->getIdentifier() != nullptr)
+      return false;
+  }
+
+  return true;
+}
+
+bool
+MicrosoftMangleContextImpl::shouldMangleStringLiteral(const StringLiteral *SL) {
+  return true;
+}
+
+void MicrosoftCXXNameMangler::mangle(const NamedDecl *D, StringRef Prefix) {
+  // MSVC doesn't mangle C++ names the same way it mangles extern "C" names.
+  // Therefore it's really important that we don't decorate the
+  // name with leading underscores or leading/trailing at signs. So, by
+  // default, we emit an asm marker at the start so we get the name right.
+  // Callers can override this with a custom prefix.
+
+  // <mangled-name> ::= ? <name> <type-encoding>
+  Out << Prefix;
+  mangleName(D);
+  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
+    mangleFunctionEncoding(FD, Context.shouldMangleDeclName(FD));
+  else if (const VarDecl *VD = dyn_cast<VarDecl>(D))
+    mangleVariableEncoding(VD);
+  else
+    llvm_unreachable("Tried to mangle unexpected NamedDecl!");
+}
+
+void MicrosoftCXXNameMangler::mangleFunctionEncoding(const FunctionDecl *FD,
+                                                     bool ShouldMangle) {
+  // <type-encoding> ::= <function-class> <function-type>
+
+  // Since MSVC operates on the type as written and not the canonical type, it
+  // actually matters which decl we have here.  MSVC appears to choose the
+  // first, since it is most likely to be the declaration in a header file.
+  FD = FD->getFirstDecl();
+
+  // We should never ever see a FunctionNoProtoType at this point.
+  // We don't even know how to mangle their types anyway :).
+  const FunctionProtoType *FT = FD->getType()->castAs<FunctionProtoType>();
+
+  // extern "C" functions can hold entities that must be mangled.
+  // As it stands, these functions still need to get expressed in the full
+  // external name.  They have their class and type omitted, replaced with '9'.
+  if (ShouldMangle) {
+    // We would like to mangle all extern "C" functions using this additional
+    // component but this would break compatibility with MSVC's behavior.
+    // Instead, do this when we know that compatibility isn't important (in
+    // other words, when it is an overloaded extern "C" function).
+    if (FD->isExternC() && FD->hasAttr<OverloadableAttr>())
+      Out << "$$J0";
+
+    mangleFunctionClass(FD);
+
+    mangleFunctionType(FT, FD, false, false);
+  } else {
+    Out << '9';
+  }
+}
+
+void MicrosoftCXXNameMangler::mangleVariableEncoding(const VarDecl *VD) {
+  // <type-encoding> ::= <storage-class> <variable-type>
+  // <storage-class> ::= 0  # private static member
+  //                 ::= 1  # protected static member
+  //                 ::= 2  # public static member
+  //                 ::= 3  # global
+  //                 ::= 4  # static local
+
+  // The first character in the encoding (after the name) is the storage class.
+  if (VD->isStaticDataMember()) {
+    // If it's a static member, it also encodes the access level.
+    switch (VD->getAccess()) {
+      default:
+      case AS_private: Out << '0'; break;
+      case AS_protected: Out << '1'; break;
+      case AS_public: Out << '2'; break;
+    }
+  }
+  else if (!VD->isStaticLocal())
+    Out << '3';
+  else
+    Out << '4';
+  // Now mangle the type.
+  // <variable-type> ::= <type> <cvr-qualifiers>
+  //                 ::= <type> <pointee-cvr-qualifiers> # pointers, references
+  // Pointers and references are odd. The type of 'int * const foo;' gets
+  // mangled as 'QAHA' instead of 'PAHB', for example.
+  SourceRange SR = VD->getSourceRange();
+  QualType Ty = VD->getType();
+  if (Ty->isPointerType() || Ty->isReferenceType() ||
+      Ty->isMemberPointerType()) {
+    mangleType(Ty, SR, QMM_Drop);
+    manglePointerExtQualifiers(
+        Ty.getDesugaredType(getASTContext()).getLocalQualifiers(), QualType());
+    if (const MemberPointerType *MPT = Ty->getAs<MemberPointerType>()) {
+      mangleQualifiers(MPT->getPointeeType().getQualifiers(), true);
+      // Member pointers are suffixed with a back reference to the member
+      // pointer's class name.
+      mangleName(MPT->getClass()->getAsCXXRecordDecl());
+    } else
+      mangleQualifiers(Ty->getPointeeType().getQualifiers(), false);
+  } else if (const ArrayType *AT = getASTContext().getAsArrayType(Ty)) {
+    // Global arrays are funny, too.
+    mangleDecayedArrayType(AT);
+    if (AT->getElementType()->isArrayType())
+      Out << 'A';
+    else
+      mangleQualifiers(Ty.getQualifiers(), false);
+  } else {
+    mangleType(Ty, SR, QMM_Drop);
+    mangleQualifiers(Ty.getQualifiers(), false);
+  }
+}
+
+void MicrosoftCXXNameMangler::mangleMemberDataPointer(const CXXRecordDecl *RD,
+                                                      const ValueDecl *VD) {
+  // <member-data-pointer> ::= <integer-literal>
+  //                       ::= $F <number> <number>
+  //                       ::= $G <number> <number> <number>
+
+  int64_t FieldOffset;
+  int64_t VBTableOffset;
+  MSInheritanceModel IM = RD->getMSInheritanceModel();
+  if (VD) {
+    FieldOffset = getASTContext().getFieldOffset(VD);
+    assert(FieldOffset % getASTContext().getCharWidth() == 0 &&
+           "cannot take address of bitfield");
+    FieldOffset /= getASTContext().getCharWidth();
+
+    VBTableOffset = 0;
+
+    if (IM == MSInheritanceModel::Virtual)
+      FieldOffset -= getASTContext().getOffsetOfBaseWithVBPtr(RD).getQuantity();
+  } else {
+    FieldOffset = RD->nullFieldOffsetIsZero() ? 0 : -1;
+
+    VBTableOffset = -1;
+  }
+
+  char Code = '\0';
+  switch (IM) {
+  case MSInheritanceModel::Single:      Code = '0'; break;
+  case MSInheritanceModel::Multiple:    Code = '0'; break;
+  case MSInheritanceModel::Virtual:     Code = 'F'; break;
+  case MSInheritanceModel::Unspecified: Code = 'G'; break;
+  }
+
+  Out << '$' << Code;
+
+  mangleNumber(FieldOffset);
+
+  // The C++ standard doesn't allow base-to-derived member pointer conversions
+  // in template parameter contexts, so the vbptr offset of data member pointers
+  // is always zero.
+  if (inheritanceModelHasVBPtrOffsetField(IM))
+    mangleNumber(0);
+  if (inheritanceModelHasVBTableOffsetField(IM))
+    mangleNumber(VBTableOffset);
+}
+
+void
+MicrosoftCXXNameMangler::mangleMemberFunctionPointer(const CXXRecordDecl *RD,
+                                                     const CXXMethodDecl *MD) {
+  // <member-function-pointer> ::= $1? <name>
+  //                           ::= $H? <name> <number>
+  //                           ::= $I? <name> <number> <number>
+  //                           ::= $J? <name> <number> <number> <number>
+
+  MSInheritanceModel IM = RD->getMSInheritanceModel();
+
+  char Code = '\0';
+  switch (IM) {
+  case MSInheritanceModel::Single:      Code = '1'; break;
+  case MSInheritanceModel::Multiple:    Code = 'H'; break;
+  case MSInheritanceModel::Virtual:     Code = 'I'; break;
+  case MSInheritanceModel::Unspecified: Code = 'J'; break;
+  }
+
+  // If non-virtual, mangle the name.  If virtual, mangle as a virtual memptr
+  // thunk.
+  uint64_t NVOffset = 0;
+  uint64_t VBTableOffset = 0;
+  uint64_t VBPtrOffset = 0;
+  if (MD) {
+    Out << '$' << Code << '?';
+    if (MD->isVirtual()) {
+      MicrosoftVTableContext *VTContext =
+          cast<MicrosoftVTableContext>(getASTContext().getVTableContext());
+      MethodVFTableLocation ML =
+          VTContext->getMethodVFTableLocation(GlobalDecl(MD));
+      mangleVirtualMemPtrThunk(MD, ML);
+      NVOffset = ML.VFPtrOffset.getQuantity();
+      VBTableOffset = ML.VBTableIndex * 4;
+      if (ML.VBase) {
+        const ASTRecordLayout &Layout = getASTContext().getASTRecordLayout(RD);
+        VBPtrOffset = Layout.getVBPtrOffset().getQuantity();
+      }
+    } else {
+      mangleName(MD);
+      mangleFunctionEncoding(MD, /*ShouldMangle=*/true);
+    }
+
+    if (VBTableOffset == 0 && IM == MSInheritanceModel::Virtual)
+      NVOffset -= getASTContext().getOffsetOfBaseWithVBPtr(RD).getQuantity();
+  } else {
+    // Null single inheritance member functions are encoded as a simple nullptr.
+    if (IM == MSInheritanceModel::Single) {
+      Out << "$0A@";
+      return;
+    }
+    if (IM == MSInheritanceModel::Unspecified)
+      VBTableOffset = -1;
+    Out << '$' << Code;
+  }
+
+  if (inheritanceModelHasNVOffsetField(/*IsMemberFunction=*/true, IM))
+    mangleNumber(static_cast<uint32_t>(NVOffset));
+  if (inheritanceModelHasVBPtrOffsetField(IM))
+    mangleNumber(VBPtrOffset);
+  if (inheritanceModelHasVBTableOffsetField(IM))
+    mangleNumber(VBTableOffset);
+}
+
+void MicrosoftCXXNameMangler::mangleVirtualMemPtrThunk(
+    const CXXMethodDecl *MD, const MethodVFTableLocation &ML) {
+  // Get the vftable offset.
+  CharUnits PointerWidth = getASTContext().toCharUnitsFromBits(
+      getASTContext().getTargetInfo().getPointerWidth(0));
+  uint64_t OffsetInVFTable = ML.Index * PointerWidth.getQuantity();
+
+  Out << "?_9";
+  mangleName(MD->getParent());
+  Out << "$B";
+  mangleNumber(OffsetInVFTable);
+  Out << 'A';
+  mangleCallingConvention(MD->getType()->castAs<FunctionProtoType>());
+}
+
+void MicrosoftCXXNameMangler::mangleName(const NamedDecl *ND) {
+  // <name> ::= <unscoped-name> {[<named-scope>]+ | [<nested-name>]}? @
+
+  // Always start with the unqualified name.
+  mangleUnqualifiedName(ND);
+
+  mangleNestedName(ND);
+
+  // Terminate the whole name with an '@'.
+  Out << '@';
+}
+
+void MicrosoftCXXNameMangler::mangleNumber(int64_t Number) {
+  // <non-negative integer> ::= A@              # when Number == 0
+  //                        ::= <decimal digit> # when 1 <= Number <= 10
+  //                        ::= <hex digit>+ @  # when Number >= 10
+  //
+  // <number>               ::= [?] <non-negative integer>
+
+  uint64_t Value = static_cast<uint64_t>(Number);
+  if (Number < 0) {
+    Value = -Value;
+    Out << '?';
+  }
+
+  if (Value == 0)
+    Out << "A@";
+  else if (Value >= 1 && Value <= 10)
+    Out << (Value - 1);
+  else {
+    // Numbers that are not encoded as decimal digits are represented as nibbles
+    // in the range of ASCII characters 'A' to 'P'.
+    // The number 0x123450 would be encoded as 'BCDEFA'
+    char EncodedNumberBuffer[sizeof(uint64_t) * 2];
+    MutableArrayRef<char> BufferRef(EncodedNumberBuffer);
+    MutableArrayRef<char>::reverse_iterator I = BufferRef.rbegin();
+    for (; Value != 0; Value >>= 4)
+      *I++ = 'A' + (Value & 0xf);
+    Out.write(I.base(), I - BufferRef.rbegin());
+    Out << '@';
+  }
+}
+
+static const TemplateDecl *
+isTemplate(const NamedDecl *ND, const TemplateArgumentList *&TemplateArgs) {
+  // Check if we have a function template.
+  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
+    if (const TemplateDecl *TD = FD->getPrimaryTemplate()) {
+      TemplateArgs = FD->getTemplateSpecializationArgs();
+      return TD;
+    }
+  }
+
+  // Check if we have a class template.
+  if (const ClassTemplateSpecializationDecl *Spec =
+          dyn_cast<ClassTemplateSpecializationDecl>(ND)) {
+    TemplateArgs = &Spec->getTemplateArgs();
+    return Spec->getSpecializedTemplate();
+  }
+
+  // Check if we have a variable template.
+  if (const VarTemplateSpecializationDecl *Spec =
+          dyn_cast<VarTemplateSpecializationDecl>(ND)) {
+    TemplateArgs = &Spec->getTemplateArgs();
+    return Spec->getSpecializedTemplate();
+  }
+
+  return nullptr;
+}
+
+void MicrosoftCXXNameMangler::mangleUnqualifiedName(const NamedDecl *ND,
+                                                    DeclarationName Name) {
+  //  <unqualified-name> ::= <operator-name>
+  //                     ::= <ctor-dtor-name>
+  //                     ::= <source-name>
+  //                     ::= <template-name>
+
+  // Check if we have a template.
+  const TemplateArgumentList *TemplateArgs = nullptr;
+  if (const TemplateDecl *TD = isTemplate(ND, TemplateArgs)) {
+    // Function templates aren't considered for name back referencing.  This
+    // makes sense since function templates aren't likely to occur multiple
+    // times in a symbol.
+    if (isa<FunctionTemplateDecl>(TD)) {
+      mangleTemplateInstantiationName(TD, *TemplateArgs);
+      Out << '@';
+      return;
+    }
+
+    // Here comes the tricky thing: if we need to mangle something like
+    //   void foo(A::X<Y>, B::X<Y>),
+    // the X<Y> part is aliased. However, if you need to mangle
+    //   void foo(A::X<A::Y>, A::X<B::Y>),
+    // the A::X<> part is not aliased.
+    // That is, from the mangler's perspective we have a structure like this:
+    //   namespace[s] -> type[ -> template-parameters]
+    // but from the Clang perspective we have
+    //   type [ -> template-parameters]
+    //      \-> namespace[s]
+    // What we do is we create a new mangler, mangle the same type (without
+    // a namespace suffix) to a string using the extra mangler and then use
+    // the mangled type name as a key to check the mangling of different types
+    // for aliasing.
+
+    // It's important to key cache reads off ND, not TD -- the same TD can
+    // be used with different TemplateArgs, but ND uniquely identifies
+    // TD / TemplateArg pairs.
+    ArgBackRefMap::iterator Found = TemplateArgBackReferences.find(ND);
+    if (Found == TemplateArgBackReferences.end()) {
+
+      TemplateArgStringMap::iterator Found = TemplateArgStrings.find(ND);
+      if (Found == TemplateArgStrings.end()) {
+        // Mangle full template name into temporary buffer.
+        llvm::SmallString<64> TemplateMangling;
+        llvm::raw_svector_ostream Stream(TemplateMangling);
+        MicrosoftCXXNameMangler Extra(Context, Stream);
+        Extra.mangleTemplateInstantiationName(TD, *TemplateArgs);
+
+        // Use the string backref vector to possibly get a back reference.
+        mangleSourceName(TemplateMangling);
+
+        // Memoize back reference for this type if one exist, else memoize
+        // the mangling itself.
+        BackRefVec::iterator StringFound =
+            llvm::find(NameBackReferences, TemplateMangling);
+        if (StringFound != NameBackReferences.end()) {
+          TemplateArgBackReferences[ND] =
+              StringFound - NameBackReferences.begin();
+        } else {
+          TemplateArgStrings[ND] =
+              TemplateArgStringStorage.save(TemplateMangling.str());
+        }
+      } else {
+        Out << Found->second << '@'; // Outputs a StringRef.
+      }
+    } else {
+      Out << Found->second; // Outputs a back reference (an int).
+    }
+    return;
+  }
+
+  switch (Name.getNameKind()) {
+    case DeclarationName::Identifier: {
+      if (const IdentifierInfo *II = Name.getAsIdentifierInfo()) {
+        mangleSourceName(II->getName());
+        break;
+      }
+
+      // Otherwise, an anonymous entity.  We must have a declaration.
+      assert(ND && "mangling empty name without declaration");
+
+      if (const NamespaceDecl *NS = dyn_cast<NamespaceDecl>(ND)) {
+        if (NS->isAnonymousNamespace()) {
+          Out << "?A0x" << Context.getAnonymousNamespaceHash() << '@';
+          break;
+        }
+      }
+
+      if (const DecompositionDecl *DD = dyn_cast<DecompositionDecl>(ND)) {
+        // Decomposition declarations are considered anonymous, and get
+        // numbered with a $S prefix.
+        llvm::SmallString<64> Name("$S");
+        // Get a unique id for the anonymous struct.
+        Name += llvm::utostr(Context.getAnonymousStructId(DD) + 1);
+        mangleSourceName(Name);
+        break;
+      }
+
+      if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
+        // We must have an anonymous union or struct declaration.
+        const CXXRecordDecl *RD = VD->getType()->getAsCXXRecordDecl();
+        assert(RD && "expected variable decl to have a record type");
+        // Anonymous types with no tag or typedef get the name of their
+        // declarator mangled in.  If they have no declarator, number them with
+        // a $S prefix.
+        llvm::SmallString<64> Name("$S");
+        // Get a unique id for the anonymous struct.
+        Name += llvm::utostr(Context.getAnonymousStructId(RD) + 1);
+        mangleSourceName(Name.str());
+        break;
+      }
+
+      // We must have an anonymous struct.
+      const TagDecl *TD = cast<TagDecl>(ND);
+      if (const TypedefNameDecl *D = TD->getTypedefNameForAnonDecl()) {
+        assert(TD->getDeclContext() == D->getDeclContext() &&
+               "Typedef should not be in another decl context!");
+        assert(D->getDeclName().getAsIdentifierInfo() &&
+               "Typedef was not named!");
+        mangleSourceName(D->getDeclName().getAsIdentifierInfo()->getName());
+        break;
+      }
+
+      if (const CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(TD)) {
+        if (Record->isLambda()) {
+          llvm::SmallString<10> Name("<lambda_");
+
+          Decl *LambdaContextDecl = Record->getLambdaContextDecl();
+          unsigned LambdaManglingNumber = Record->getLambdaManglingNumber();
+          unsigned LambdaId;
+          const ParmVarDecl *Parm =
+              dyn_cast_or_null<ParmVarDecl>(LambdaContextDecl);
+          const FunctionDecl *Func =
+              Parm ? dyn_cast<FunctionDecl>(Parm->getDeclContext()) : nullptr;
+
+          if (Func) {
+            unsigned DefaultArgNo =
+                Func->getNumParams() - Parm->getFunctionScopeIndex();
+            Name += llvm::utostr(DefaultArgNo);
+            Name += "_";
+          }
+
+          if (LambdaManglingNumber)
+            LambdaId = LambdaManglingNumber;
+          else
+            LambdaId = Context.getLambdaId(Record);
+
+          Name += llvm::utostr(LambdaId);
+          Name += ">";
+
+          mangleSourceName(Name);
+
+          // If the context of a closure type is an initializer for a class
+          // member (static or nonstatic), it is encoded in a qualified name.
+          if (LambdaManglingNumber && LambdaContextDecl) {
+            if ((isa<VarDecl>(LambdaContextDecl) ||
+                 isa<FieldDecl>(LambdaContextDecl)) &&
+                LambdaContextDecl->getDeclContext()->isRecord()) {
+              mangleUnqualifiedName(cast<NamedDecl>(LambdaContextDecl));
+            }
+          }
+          break;
+        }
+      }
+
+      llvm::SmallString<64> Name;
+      if (DeclaratorDecl *DD =
+              Context.getASTContext().getDeclaratorForUnnamedTagDecl(TD)) {
+        // Anonymous types without a name for linkage purposes have their
+        // declarator mangled in if they have one.
+        Name += "<unnamed-type-";
+        Name += DD->getName();
+      } else if (TypedefNameDecl *TND =
+                     Context.getASTContext().getTypedefNameForUnnamedTagDecl(
+                         TD)) {
+        // Anonymous types without a name for linkage purposes have their
+        // associate typedef mangled in if they have one.
+        Name += "<unnamed-type-";
+        Name += TND->getName();
+      } else if (isa<EnumDecl>(TD) &&
+                 cast<EnumDecl>(TD)->enumerator_begin() !=
+                     cast<EnumDecl>(TD)->enumerator_end()) {
+        // Anonymous non-empty enums mangle in the first enumerator.
+        auto *ED = cast<EnumDecl>(TD);
+        Name += "<unnamed-enum-";
+        Name += ED->enumerator_begin()->getName();
+      } else {
+        // Otherwise, number the types using a $S prefix.
+        Name += "<unnamed-type-$S";
+        Name += llvm::utostr(Context.getAnonymousStructId(TD) + 1);
+      }
+      Name += ">";
+      mangleSourceName(Name.str());
+      break;
+    }
+
+    case DeclarationName::ObjCZeroArgSelector:
+    case DeclarationName::ObjCOneArgSelector:
+    case DeclarationName::ObjCMultiArgSelector: {
+      // This is reachable only when constructing an outlined SEH finally
+      // block.  Nothing depends on this mangling and it's used only with
+      // functinos with internal linkage.
+      llvm::SmallString<64> Name;
+      mangleSourceName(Name.str());
+      break;
+    }
+
+    case DeclarationName::CXXConstructorName:
+      if (isStructorDecl(ND)) {
+        if (StructorType == Ctor_CopyingClosure) {
+          Out << "?_O";
+          return;
+        }
+        if (StructorType == Ctor_DefaultClosure) {
+          Out << "?_F";
+          return;
+        }
+      }
+      Out << "?0";
+      return;
+
+    case DeclarationName::CXXDestructorName:
+      if (isStructorDecl(ND))
+        // If the named decl is the C++ destructor we're mangling,
+        // use the type we were given.
+        mangleCXXDtorType(static_cast<CXXDtorType>(StructorType));
+      else
+        // Otherwise, use the base destructor name. This is relevant if a
+        // class with a destructor is declared within a destructor.
+        mangleCXXDtorType(Dtor_Base);
+      break;
+
+    case DeclarationName::CXXConversionFunctionName:
+      // <operator-name> ::= ?B # (cast)
+      // The target type is encoded as the return type.
+      Out << "?B";
+      break;
+
+    case DeclarationName::CXXOperatorName:
+      mangleOperatorName(Name.getCXXOverloadedOperator(), ND->getLocation());
+      break;
+
+    case DeclarationName::CXXLiteralOperatorName: {
+      Out << "?__K";
+      mangleSourceName(Name.getCXXLiteralIdentifier()->getName());
+      break;
+    }
+
+    case DeclarationName::CXXDeductionGuideName:
+      llvm_unreachable("Can't mangle a deduction guide name!");
+
+    case DeclarationName::CXXUsingDirective:
+      llvm_unreachable("Can't mangle a using directive name!");
+  }
+}
+
+// <postfix> ::= <unqualified-name> [<postfix>]
+//           ::= <substitution> [<postfix>]
+void MicrosoftCXXNameMangler::mangleNestedName(const NamedDecl *ND) {
+  const DeclContext *DC = getEffectiveDeclContext(ND);
+  while (!DC->isTranslationUnit()) {
+    if (isa<TagDecl>(ND) || isa<VarDecl>(ND)) {
+      unsigned Disc;
+      if (Context.getNextDiscriminator(ND, Disc)) {
+        Out << '?';
+        mangleNumber(Disc);
+        Out << '?';
+      }
+    }
+
+    if (const BlockDecl *BD = dyn_cast<BlockDecl>(DC)) {
+      auto Discriminate =
+          [](StringRef Name, const unsigned Discriminator,
+             const unsigned ParameterDiscriminator) -> std::string {
+        std::string Buffer;
+        llvm::raw_string_ostream Stream(Buffer);
+        Stream << Name;
+        if (Discriminator)
+          Stream << '_' << Discriminator;
+        if (ParameterDiscriminator)
+          Stream << '_' << ParameterDiscriminator;
+        return Stream.str();
+      };
+
+      unsigned Discriminator = BD->getBlockManglingNumber();
+      if (!Discriminator)
+        Discriminator = Context.getBlockId(BD, /*Local=*/false);
+
+      // Mangle the parameter position as a discriminator to deal with unnamed
+      // parameters.  Rather than mangling the unqualified parameter name,
+      // always use the position to give a uniform mangling.
+      unsigned ParameterDiscriminator = 0;
+      if (const auto *MC = BD->getBlockManglingContextDecl())
+        if (const auto *P = dyn_cast<ParmVarDecl>(MC))
+          if (const auto *F = dyn_cast<FunctionDecl>(P->getDeclContext()))
+            ParameterDiscriminator =
+                F->getNumParams() - P->getFunctionScopeIndex();
+
+      DC = getEffectiveDeclContext(BD);
+
+      Out << '?';
+      mangleSourceName(Discriminate("_block_invoke", Discriminator,
+                                    ParameterDiscriminator));
+      // If we have a block mangling context, encode that now.  This allows us
+      // to discriminate between named static data initializers in the same
+      // scope.  This is handled differently from parameters, which use
+      // positions to discriminate between multiple instances.
+      if (const auto *MC = BD->getBlockManglingContextDecl())
+        if (!isa<ParmVarDecl>(MC))
+          if (const auto *ND = dyn_cast<NamedDecl>(MC))
+            mangleUnqualifiedName(ND);
+      // MS ABI and Itanium manglings are in inverted scopes.  In the case of a
+      // RecordDecl, mangle the entire scope hierarchy at this point rather than
+      // just the unqualified name to get the ordering correct.
+      if (const auto *RD = dyn_cast<RecordDecl>(DC))
+        mangleName(RD);
+      else
+        Out << '@';
+      // void __cdecl
+      Out << "YAX";
+      // struct __block_literal *
+      Out << 'P';
+      // __ptr64
+      if (PointersAre64Bit)
+        Out << 'E';
+      Out << 'A';
+      mangleArtificialTagType(TTK_Struct,
+                             Discriminate("__block_literal", Discriminator,
+                                          ParameterDiscriminator));
+      Out << "@Z";
+
+      // If the effective context was a Record, we have fully mangled the
+      // qualified name and do not need to continue.
+      if (isa<RecordDecl>(DC))
+        break;
+      continue;
+    } else if (const ObjCMethodDecl *Method = dyn_cast<ObjCMethodDecl>(DC)) {
+      mangleObjCMethodName(Method);
+    } else if (isa<NamedDecl>(DC)) {
+      ND = cast<NamedDecl>(DC);
+      if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
+        mangle(FD, "?");
+        break;
+      } else {
+        mangleUnqualifiedName(ND);
+        // Lambdas in default arguments conceptually belong to the function the
+        // parameter corresponds to.
+        if (const auto *LDADC = getLambdaDefaultArgumentDeclContext(ND)) {
+          DC = LDADC;
+          continue;
+        }
+      }
+    }
+    DC = DC->getParent();
+  }
+}
+
+void MicrosoftCXXNameMangler::mangleCXXDtorType(CXXDtorType T) {
+  // Microsoft uses the names on the case labels for these dtor variants.  Clang
+  // uses the Itanium terminology internally.  Everything in this ABI delegates
+  // towards the base dtor.
+  switch (T) {
+  // <operator-name> ::= ?1  # destructor
+  case Dtor_Base: Out << "?1"; return;
+  // <operator-name> ::= ?_D # vbase destructor
+  case Dtor_Complete: Out << "?_D"; return;
+  // <operator-name> ::= ?_G # scalar deleting destructor
+  case Dtor_Deleting: Out << "?_G"; return;
+  // <operator-name> ::= ?_E # vector deleting destructor
+  // FIXME: Add a vector deleting dtor type.  It goes in the vtable, so we need
+  // it.
+  case Dtor_Comdat:
+    llvm_unreachable("not expecting a COMDAT");
+  }
+  llvm_unreachable("Unsupported dtor type?");
+}
+
+void MicrosoftCXXNameMangler::mangleOperatorName(OverloadedOperatorKind OO,
+                                                 SourceLocation Loc) {
+  switch (OO) {
+  //                     ?0 # constructor
+  //                     ?1 # destructor
+  // <operator-name> ::= ?2 # new
+  case OO_New: Out << "?2"; break;
+  // <operator-name> ::= ?3 # delete
+  case OO_Delete: Out << "?3"; break;
+  // <operator-name> ::= ?4 # =
+  case OO_Equal: Out << "?4"; break;
+  // <operator-name> ::= ?5 # >>
+  case OO_GreaterGreater: Out << "?5"; break;
+  // <operator-name> ::= ?6 # <<
+  case OO_LessLess: Out << "?6"; break;
+  // <operator-name> ::= ?7 # !
+  case OO_Exclaim: Out << "?7"; break;
+  // <operator-name> ::= ?8 # ==
+  case OO_EqualEqual: Out << "?8"; break;
+  // <operator-name> ::= ?9 # !=
+  case OO_ExclaimEqual: Out << "?9"; break;
+  // <operator-name> ::= ?A # []
+  case OO_Subscript: Out << "?A"; break;
+  //                     ?B # conversion
+  // <operator-name> ::= ?C # ->
+  case OO_Arrow: Out << "?C"; break;
+  // <operator-name> ::= ?D # *
+  case OO_Star: Out << "?D"; break;
+  // <operator-name> ::= ?E # ++
+  case OO_PlusPlus: Out << "?E"; break;
+  // <operator-name> ::= ?F # --
+  case OO_MinusMinus: Out << "?F"; break;
+  // <operator-name> ::= ?G # -
+  case OO_Minus: Out << "?G"; break;
+  // <operator-name> ::= ?H # +
+  case OO_Plus: Out << "?H"; break;
+  // <operator-name> ::= ?I # &
+  case OO_Amp: Out << "?I"; break;
+  // <operator-name> ::= ?J # ->*
+  case OO_ArrowStar: Out << "?J"; break;
+  // <operator-name> ::= ?K # /
+  case OO_Slash: Out << "?K"; break;
+  // <operator-name> ::= ?L # %
+  case OO_Percent: Out << "?L"; break;
+  // <operator-name> ::= ?M # <
+  case OO_Less: Out << "?M"; break;
+  // <operator-name> ::= ?N # <=
+  case OO_LessEqual: Out << "?N"; break;
+  // <operator-name> ::= ?O # >
+  case OO_Greater: Out << "?O"; break;
+  // <operator-name> ::= ?P # >=
+  case OO_GreaterEqual: Out << "?P"; break;
+  // <operator-name> ::= ?Q # ,
+  case OO_Comma: Out << "?Q"; break;
+  // <operator-name> ::= ?R # ()
+  case OO_Call: Out << "?R"; break;
+  // <operator-name> ::= ?S # ~
+  case OO_Tilde: Out << "?S"; break;
+  // <operator-name> ::= ?T # ^
+  case OO_Caret: Out << "?T"; break;
+  // <operator-name> ::= ?U # |
+  case OO_Pipe: Out << "?U"; break;
+  // <operator-name> ::= ?V # &&
+  case OO_AmpAmp: Out << "?V"; break;
+  // <operator-name> ::= ?W # ||
+  case OO_PipePipe: Out << "?W"; break;
+  // <operator-name> ::= ?X # *=
+  case OO_StarEqual: Out << "?X"; break;
+  // <operator-name> ::= ?Y # +=
+  case OO_PlusEqual: Out << "?Y"; break;
+  // <operator-name> ::= ?Z # -=
+  case OO_MinusEqual: Out << "?Z"; break;
+  // <operator-name> ::= ?_0 # /=
+  case OO_SlashEqual: Out << "?_0"; break;
+  // <operator-name> ::= ?_1 # %=
+  case OO_PercentEqual: Out << "?_1"; break;
+  // <operator-name> ::= ?_2 # >>=
+  case OO_GreaterGreaterEqual: Out << "?_2"; break;
+  // <operator-name> ::= ?_3 # <<=
+  case OO_LessLessEqual: Out << "?_3"; break;
+  // <operator-name> ::= ?_4 # &=
+  case OO_AmpEqual: Out << "?_4"; break;
+  // <operator-name> ::= ?_5 # |=
+  case OO_PipeEqual: Out << "?_5"; break;
+  // <operator-name> ::= ?_6 # ^=
+  case OO_CaretEqual: Out << "?_6"; break;
+  //                     ?_7 # vftable
+  //                     ?_8 # vbtable
+  //                     ?_9 # vcall
+  //                     ?_A # typeof
+  //                     ?_B # local static guard
+  //                     ?_C # string
+  //                     ?_D # vbase destructor
+  //                     ?_E # vector deleting destructor
+  //                     ?_F # default constructor closure
+  //                     ?_G # scalar deleting destructor
+  //                     ?_H # vector constructor iterator
+  //                     ?_I # vector destructor iterator
+  //                     ?_J # vector vbase constructor iterator
+  //                     ?_K # virtual displacement map
+  //                     ?_L # eh vector constructor iterator
+  //                     ?_M # eh vector destructor iterator
+  //                     ?_N # eh vector vbase constructor iterator
+  //                     ?_O # copy constructor closure
+  //                     ?_P<name> # udt returning <name>
+  //                     ?_Q # <unknown>
+  //                     ?_R0 # RTTI Type Descriptor
+  //                     ?_R1 # RTTI Base Class Descriptor at (a,b,c,d)
+  //                     ?_R2 # RTTI Base Class Array
+  //                     ?_R3 # RTTI Class Hierarchy Descriptor
+  //                     ?_R4 # RTTI Complete Object Locator
+  //                     ?_S # local vftable
+  //                     ?_T # local vftable constructor closure
+  // <operator-name> ::= ?_U # new[]
+  case OO_Array_New: Out << "?_U"; break;
+  // <operator-name> ::= ?_V # delete[]
+  case OO_Array_Delete: Out << "?_V"; break;
+  // <operator-name> ::= ?__L # co_await
+  case OO_Coawait: Out << "?__L"; break;
+  // <operator-name> ::= ?__M # <=>
+  case OO_Spaceship: Out << "?__M"; break;
+
+  case OO_Conditional: {
+    DiagnosticsEngine &Diags = Context.getDiags();
+    unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
+      "cannot mangle this conditional operator yet");
+    Diags.Report(Loc, DiagID);
+    break;
+  }
+
+  case OO_None:
+  case NUM_OVERLOADED_OPERATORS:
+    llvm_unreachable("Not an overloaded operator");
+  }
+}
+
+void MicrosoftCXXNameMangler::mangleSourceName(StringRef Name) {
+  // <source name> ::= <identifier> @
+  BackRefVec::iterator Found = llvm::find(NameBackReferences, Name);
+  if (Found == NameBackReferences.end()) {
+    if (NameBackReferences.size() < 10)
+      NameBackReferences.push_back(std::string(Name));
+    Out << Name << '@';
+  } else {
+    Out << (Found - NameBackReferences.begin());
+  }
+}
+
+void MicrosoftCXXNameMangler::mangleObjCMethodName(const ObjCMethodDecl *MD) {
+  Context.mangleObjCMethodName(MD, Out);
+}
+
+void MicrosoftCXXNameMangler::mangleTemplateInstantiationName(
+    const TemplateDecl *TD, const TemplateArgumentList &TemplateArgs) {
+  // <template-name> ::= <unscoped-template-name> <template-args>
+  //                 ::= <substitution>
+  // Always start with the unqualified name.
+
+  // Templates have their own context for back references.
+  ArgBackRefMap OuterFunArgsContext;
+  ArgBackRefMap OuterTemplateArgsContext;
+  BackRefVec OuterTemplateContext;
+  PassObjectSizeArgsSet OuterPassObjectSizeArgs;
+  NameBackReferences.swap(OuterTemplateContext);
+  FunArgBackReferences.swap(OuterFunArgsContext);
+  TemplateArgBackReferences.swap(OuterTemplateArgsContext);
+  PassObjectSizeArgs.swap(OuterPassObjectSizeArgs);
+
+  mangleUnscopedTemplateName(TD);
+  mangleTemplateArgs(TD, TemplateArgs);
+
+  // Restore the previous back reference contexts.
+  NameBackReferences.swap(OuterTemplateContext);
+  FunArgBackReferences.swap(OuterFunArgsContext);
+  TemplateArgBackReferences.swap(OuterTemplateArgsContext);
+  PassObjectSizeArgs.swap(OuterPassObjectSizeArgs);
+}
+
+void
+MicrosoftCXXNameMangler::mangleUnscopedTemplateName(const TemplateDecl *TD) {
+  // <unscoped-template-name> ::= ?$ <unqualified-name>
+  Out << "?$";
+  mangleUnqualifiedName(TD);
+}
+
+void MicrosoftCXXNameMangler::mangleIntegerLiteral(const llvm::APSInt &Value,
+                                                   bool IsBoolean) {
+  // <integer-literal> ::= $0 <number>
+  Out << "$0";
+  // Make sure booleans are encoded as 0/1.
+  if (IsBoolean && Value.getBoolValue())
+    mangleNumber(1);
+  else if (Value.isSigned())
+    mangleNumber(Value.getSExtValue());
+  else
+    mangleNumber(Value.getZExtValue());
+}
+
+void MicrosoftCXXNameMangler::mangleExpression(const Expr *E) {
+  // See if this is a constant expression.
+  llvm::APSInt Value;
+  if (E->isIntegerConstantExpr(Value, Context.getASTContext())) {
+    mangleIntegerLiteral(Value, E->getType()->isBooleanType());
+    return;
+  }
+
+  // Look through no-op casts like template parameter substitutions.
+  E = E->IgnoreParenNoopCasts(Context.getASTContext());
+
+  const CXXUuidofExpr *UE = nullptr;
+  if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
+    if (UO->getOpcode() == UO_AddrOf)
+      UE = dyn_cast<CXXUuidofExpr>(UO->getSubExpr());
+  } else
+    UE = dyn_cast<CXXUuidofExpr>(E);
+
+  if (UE) {
+    // If we had to peek through an address-of operator, treat this like we are
+    // dealing with a pointer type.  Otherwise, treat it like a const reference.
+    //
+    // N.B. This matches up with the handling of TemplateArgument::Declaration
+    // in mangleTemplateArg
+    if (UE == E)
+      Out << "$E?";
+    else
+      Out << "$1?";
+
+    // This CXXUuidofExpr is mangled as-if it were actually a VarDecl from
+    // const __s_GUID _GUID_{lower case UUID with underscores}
+    StringRef Uuid = UE->getUuidStr();
+    std::string Name = "_GUID_" + Uuid.lower();
+    std::replace(Name.begin(), Name.end(), '-', '_');
+
+    mangleSourceName(Name);
+    // Terminate the whole name with an '@'.
+    Out << '@';
+    // It's a global variable.
+    Out << '3';
+    // It's a struct called __s_GUID.
+    mangleArtificialTagType(TTK_Struct, "__s_GUID");
+    // It's const.
+    Out << 'B';
+    return;
+  }
+
+  // As bad as this diagnostic is, it's better than crashing.
+  DiagnosticsEngine &Diags = Context.getDiags();
+  unsigned DiagID = Diags.getCustomDiagID(
+      DiagnosticsEngine::Error, "cannot yet mangle expression type %0");
+  Diags.Report(E->getExprLoc(), DiagID) << E->getStmtClassName()
+                                        << E->getSourceRange();
+}
+
+void MicrosoftCXXNameMangler::mangleTemplateArgs(
+    const TemplateDecl *TD, const TemplateArgumentList &TemplateArgs) {
+  // <template-args> ::= <template-arg>+
+  const TemplateParameterList *TPL = TD->getTemplateParameters();
+  assert(TPL->size() == TemplateArgs.size() &&
+         "size mismatch between args and parms!");
+
+  for (size_t i = 0; i < TemplateArgs.size(); ++i) {
+    const TemplateArgument &TA = TemplateArgs[i];
+
+    // Separate consecutive packs by $$Z.
+    if (i > 0 && TA.getKind() == TemplateArgument::Pack &&
+        TemplateArgs[i - 1].getKind() == TemplateArgument::Pack)
+      Out << "$$Z";
+
+    mangleTemplateArg(TD, TA, TPL->getParam(i));
+  }
+}
+
+void MicrosoftCXXNameMangler::mangleTemplateArg(const TemplateDecl *TD,
+                                                const TemplateArgument &TA,
+                                                const NamedDecl *Parm) {
+  // <template-arg> ::= <type>
+  //                ::= <integer-literal>
+  //                ::= <member-data-pointer>
+  //                ::= <member-function-pointer>
+  //                ::= $E? <name> <type-encoding>
+  //                ::= $1? <name> <type-encoding>
+  //                ::= $0A@
+  //                ::= <template-args>
+
+  switch (TA.getKind()) {
+  case TemplateArgument::Null:
+    llvm_unreachable("Can't mangle null template arguments!");
+  case TemplateArgument::TemplateExpansion:
+    llvm_unreachable("Can't mangle template expansion arguments!");
+  case TemplateArgument::Type: {
+    QualType T = TA.getAsType();
+    mangleType(T, SourceRange(), QMM_Escape);
+    break;
+  }
+  case TemplateArgument::Declaration: {
+    const NamedDecl *ND = TA.getAsDecl();
+    if (isa<FieldDecl>(ND) || isa<IndirectFieldDecl>(ND)) {
+      mangleMemberDataPointer(cast<CXXRecordDecl>(ND->getDeclContext())
+                                  ->getMostRecentNonInjectedDecl(),
+                              cast<ValueDecl>(ND));
+    } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
+      const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
+      if (MD && MD->isInstance()) {
+        mangleMemberFunctionPointer(
+            MD->getParent()->getMostRecentNonInjectedDecl(), MD);
+      } else {
+        Out << "$1?";
+        mangleName(FD);
+        mangleFunctionEncoding(FD, /*ShouldMangle=*/true);
+      }
+    } else {
+      mangle(ND, TA.getParamTypeForDecl()->isReferenceType() ? "$E?" : "$1?");
+    }
+    break;
+  }
+  case TemplateArgument::Integral:
+    mangleIntegerLiteral(TA.getAsIntegral(),
+                         TA.getIntegralType()->isBooleanType());
+    break;
+  case TemplateArgument::NullPtr: {
+    QualType T = TA.getNullPtrType();
+    if (const MemberPointerType *MPT = T->getAs<MemberPointerType>()) {
+      const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
+      if (MPT->isMemberFunctionPointerType() &&
+          !isa<FunctionTemplateDecl>(TD)) {
+        mangleMemberFunctionPointer(RD, nullptr);
+        return;
+      }
+      if (MPT->isMemberDataPointer()) {
+        if (!isa<FunctionTemplateDecl>(TD)) {
+          mangleMemberDataPointer(RD, nullptr);
+          return;
+        }
+        // nullptr data pointers are always represented with a single field
+        // which is initialized with either 0 or -1.  Why -1?  Well, we need to
+        // distinguish the case where the data member is at offset zero in the
+        // record.
+        // However, we are free to use 0 *if* we would use multiple fields for
+        // non-nullptr member pointers.
+        if (!RD->nullFieldOffsetIsZero()) {
+          mangleIntegerLiteral(llvm::APSInt::get(-1), /*IsBoolean=*/false);
+          return;
+        }
+      }
+    }
+    mangleIntegerLiteral(llvm::APSInt::getUnsigned(0), /*IsBoolean=*/false);
+    break;
+  }
+  case TemplateArgument::Expression:
+    mangleExpression(TA.getAsExpr());
+    break;
+  case TemplateArgument::Pack: {
+    ArrayRef<TemplateArgument> TemplateArgs = TA.getPackAsArray();
+    if (TemplateArgs.empty()) {
+      if (isa<TemplateTypeParmDecl>(Parm) ||
+          isa<TemplateTemplateParmDecl>(Parm))
+        // MSVC 2015 changed the mangling for empty expanded template packs,
+        // use the old mangling for link compatibility for old versions.
+        Out << (Context.getASTContext().getLangOpts().isCompatibleWithMSVC(
+                    LangOptions::MSVC2015)
+                    ? "$$V"
+                    : "$$$V");
+      else if (isa<NonTypeTemplateParmDecl>(Parm))
+        Out << "$S";
+      else
+        llvm_unreachable("unexpected template parameter decl!");
+    } else {
+      for (const TemplateArgument &PA : TemplateArgs)
+        mangleTemplateArg(TD, PA, Parm);
+    }
+    break;
+  }
+  case TemplateArgument::Template: {
+    const NamedDecl *ND =
+        TA.getAsTemplate().getAsTemplateDecl()->getTemplatedDecl();
+    if (const auto *TD = dyn_cast<TagDecl>(ND)) {
+      mangleType(TD);
+    } else if (isa<TypeAliasDecl>(ND)) {
+      Out << "$$Y";
+      mangleName(ND);
+    } else {
+      llvm_unreachable("unexpected template template NamedDecl!");
+    }
+    break;
+  }
+  }
+}
+
+void MicrosoftCXXNameMangler::mangleObjCProtocol(const ObjCProtocolDecl *PD) {
+  llvm::SmallString<64> TemplateMangling;
+  llvm::raw_svector_ostream Stream(TemplateMangling);
+  MicrosoftCXXNameMangler Extra(Context, Stream);
+
+  Stream << "?$";
+  Extra.mangleSourceName("Protocol");
+  Extra.mangleArtificialTagType(TTK_Struct, PD->getName());
+
+  mangleArtificialTagType(TTK_Struct, TemplateMangling, {"__ObjC"});
+}
+
+void MicrosoftCXXNameMangler::mangleObjCLifetime(const QualType Type,
+                                                 Qualifiers Quals,
+                                                 SourceRange Range) {
+  llvm::SmallString<64> TemplateMangling;
+  llvm::raw_svector_ostream Stream(TemplateMangling);
+  MicrosoftCXXNameMangler Extra(Context, Stream);
+
+  Stream << "?$";
+  switch (Quals.getObjCLifetime()) {
+  case Qualifiers::OCL_None:
+  case Qualifiers::OCL_ExplicitNone:
+    break;
+  case Qualifiers::OCL_Autoreleasing:
+    Extra.mangleSourceName("Autoreleasing");
+    break;
+  case Qualifiers::OCL_Strong:
+    Extra.mangleSourceName("Strong");
+    break;
+  case Qualifiers::OCL_Weak:
+    Extra.mangleSourceName("Weak");
+    break;
+  }
+  Extra.manglePointerCVQualifiers(Quals);
+  Extra.manglePointerExtQualifiers(Quals, Type);
+  Extra.mangleType(Type, Range);
+
+  mangleArtificialTagType(TTK_Struct, TemplateMangling, {"__ObjC"});
+}
+
+void MicrosoftCXXNameMangler::mangleObjCKindOfType(const ObjCObjectType *T,
+                                                   Qualifiers Quals,
+                                                   SourceRange Range) {
+  llvm::SmallString<64> TemplateMangling;
+  llvm::raw_svector_ostream Stream(TemplateMangling);
+  MicrosoftCXXNameMangler Extra(Context, Stream);
+
+  Stream << "?$";
+  Extra.mangleSourceName("KindOf");
+  Extra.mangleType(QualType(T, 0)
+                       .stripObjCKindOfType(getASTContext())
+                       ->getAs<ObjCObjectType>(),
+                   Quals, Range);
+
+  mangleArtificialTagType(TTK_Struct, TemplateMangling, {"__ObjC"});
+}
+
+void MicrosoftCXXNameMangler::mangleQualifiers(Qualifiers Quals,
+                                               bool IsMember) {
+  // <cvr-qualifiers> ::= [E] [F] [I] <base-cvr-qualifiers>
+  // 'E' means __ptr64 (32-bit only); 'F' means __unaligned (32/64-bit only);
+  // 'I' means __restrict (32/64-bit).
+  // Note that the MSVC __restrict keyword isn't the same as the C99 restrict
+  // keyword!
+  // <base-cvr-qualifiers> ::= A  # near
+  //                       ::= B  # near const
+  //                       ::= C  # near volatile
+  //                       ::= D  # near const volatile
+  //                       ::= E  # far (16-bit)
+  //                       ::= F  # far const (16-bit)
+  //                       ::= G  # far volatile (16-bit)
+  //                       ::= H  # far const volatile (16-bit)
+  //                       ::= I  # huge (16-bit)
+  //                       ::= J  # huge const (16-bit)
+  //                       ::= K  # huge volatile (16-bit)
+  //                       ::= L  # huge const volatile (16-bit)
+  //                       ::= M <basis> # based
+  //                       ::= N <basis> # based const
+  //                       ::= O <basis> # based volatile
+  //                       ::= P <basis> # based const volatile
+  //                       ::= Q  # near member
+  //                       ::= R  # near const member
+  //                       ::= S  # near volatile member
+  //                       ::= T  # near const volatile member
+  //                       ::= U  # far member (16-bit)
+  //                       ::= V  # far const member (16-bit)
+  //                       ::= W  # far volatile member (16-bit)
+  //                       ::= X  # far const volatile member (16-bit)
+  //                       ::= Y  # huge member (16-bit)
+  //                       ::= Z  # huge const member (16-bit)
+  //                       ::= 0  # huge volatile member (16-bit)
+  //                       ::= 1  # huge const volatile member (16-bit)
+  //                       ::= 2 <basis> # based member
+  //                       ::= 3 <basis> # based const member
+  //                       ::= 4 <basis> # based volatile member
+  //                       ::= 5 <basis> # based const volatile member
+  //                       ::= 6  # near function (pointers only)
+  //                       ::= 7  # far function (pointers only)
+  //                       ::= 8  # near method (pointers only)
+  //                       ::= 9  # far method (pointers only)
+  //                       ::= _A <basis> # based function (pointers only)
+  //                       ::= _B <basis> # based function (far?) (pointers only)
+  //                       ::= _C <basis> # based method (pointers only)
+  //                       ::= _D <basis> # based method (far?) (pointers only)
+  //                       ::= _E # block (Clang)
+  // <basis> ::= 0 # __based(void)
+  //         ::= 1 # __based(segment)?
+  //         ::= 2 <name> # __based(name)
+  //         ::= 3 # ?
+  //         ::= 4 # ?
+  //         ::= 5 # not really based
+  bool HasConst = Quals.hasConst(),
+       HasVolatile = Quals.hasVolatile();
+
+  if (!IsMember) {
+    if (HasConst && HasVolatile) {
+      Out << 'D';
+    } else if (HasVolatile) {
+      Out << 'C';
+    } else if (HasConst) {
+      Out << 'B';
+    } else {
+      Out << 'A';
+    }
+  } else {
+    if (HasConst && HasVolatile) {
+      Out << 'T';
+    } else if (HasVolatile) {
+      Out << 'S';
+    } else if (HasConst) {
+      Out << 'R';
+    } else {
+      Out << 'Q';
+    }
+  }
+
+  // FIXME: For now, just drop all extension qualifiers on the floor.
+}
+
+void
+MicrosoftCXXNameMangler::mangleRefQualifier(RefQualifierKind RefQualifier) {
+  // <ref-qualifier> ::= G                # lvalue reference
+  //                 ::= H                # rvalue-reference
+  switch (RefQualifier) {
+  case RQ_None:
+    break;
+
+  case RQ_LValue:
+    Out << 'G';
+    break;
+
+  case RQ_RValue:
+    Out << 'H';
+    break;
+  }
+}
+
+void MicrosoftCXXNameMangler::manglePointerExtQualifiers(Qualifiers Quals,
+                                                         QualType PointeeType) {
+  // Check if this is a default 64-bit pointer or has __ptr64 qualifier.
+  bool is64Bit = PointeeType.isNull() ? PointersAre64Bit :
+      is64BitPointer(PointeeType.getQualifiers());
+  if (is64Bit && (PointeeType.isNull() || !PointeeType->isFunctionType()))
+    Out << 'E';
+
+  if (Quals.hasRestrict())
+    Out << 'I';
+
+  if (Quals.hasUnaligned() ||
+      (!PointeeType.isNull() && PointeeType.getLocalQualifiers().hasUnaligned()))
+    Out << 'F';
+}
+
+void MicrosoftCXXNameMangler::manglePointerCVQualifiers(Qualifiers Quals) {
+  // <pointer-cv-qualifiers> ::= P  # no qualifiers
+  //                         ::= Q  # const
+  //                         ::= R  # volatile
+  //                         ::= S  # const volatile
+  bool HasConst = Quals.hasConst(),
+       HasVolatile = Quals.hasVolatile();
+
+  if (HasConst && HasVolatile) {
+    Out << 'S';
+  } else if (HasVolatile) {
+    Out << 'R';
+  } else if (HasConst) {
+    Out << 'Q';
+  } else {
+    Out << 'P';
+  }
+}
+
+void MicrosoftCXXNameMangler::mangleFunctionArgumentType(QualType T,
+                                                         SourceRange Range) {
+  // MSVC will backreference two canonically equivalent types that have slightly
+  // different manglings when mangled alone.
+
+  // Decayed types do not match up with non-decayed versions of the same type.
+  //
+  // e.g.
+  // void (*x)(void) will not form a backreference with void x(void)
+  void *TypePtr;
+  if (const auto *DT = T->getAs<DecayedType>()) {
+    QualType OriginalType = DT->getOriginalType();
+    // All decayed ArrayTypes should be treated identically; as-if they were
+    // a decayed IncompleteArrayType.
+    if (const auto *AT = getASTContext().getAsArrayType(OriginalType))
+      OriginalType = getASTContext().getIncompleteArrayType(
+          AT->getElementType(), AT->getSizeModifier(),
+          AT->getIndexTypeCVRQualifiers());
+
+    TypePtr = OriginalType.getCanonicalType().getAsOpaquePtr();
+    // If the original parameter was textually written as an array,
+    // instead treat the decayed parameter like it's const.
+    //
+    // e.g.
+    // int [] -> int * const
+    if (OriginalType->isArrayType())
+      T = T.withConst();
+  } else {
+    TypePtr = T.getCanonicalType().getAsOpaquePtr();
+  }
+
+  ArgBackRefMap::iterator Found = FunArgBackReferences.find(TypePtr);
+
+  if (Found == FunArgBackReferences.end()) {
+    size_t OutSizeBefore = Out.tell();
+
+    mangleType(T, Range, QMM_Drop);
+
+    // See if it's worth creating a back reference.
+    // Only types longer than 1 character are considered
+    // and only 10 back references slots are available:
+    bool LongerThanOneChar = (Out.tell() - OutSizeBefore > 1);
+    if (LongerThanOneChar && FunArgBackReferences.size() < 10) {
+      size_t Size = FunArgBackReferences.size();
+      FunArgBackReferences[TypePtr] = Size;
+    }
+  } else {
+    Out << Found->second;
+  }
+}
+
+void MicrosoftCXXNameMangler::manglePassObjectSizeArg(
+    const PassObjectSizeAttr *POSA) {
+  int Type = POSA->getType();
+  bool Dynamic = POSA->isDynamic();
+
+  auto Iter = PassObjectSizeArgs.insert({Type, Dynamic}).first;
+  auto *TypePtr = (const void *)&*Iter;
+  ArgBackRefMap::iterator Found = FunArgBackReferences.find(TypePtr);
+
+  if (Found == FunArgBackReferences.end()) {
+    std::string Name =
+        Dynamic ? "__pass_dynamic_object_size" : "__pass_object_size";
+    mangleArtificialTagType(TTK_Enum, Name + llvm::utostr(Type), {"__clang"});
+
+    if (FunArgBackReferences.size() < 10) {
+      size_t Size = FunArgBackReferences.size();
+      FunArgBackReferences[TypePtr] = Size;
+    }
+  } else {
+    Out << Found->second;
+  }
+}
+
+void MicrosoftCXXNameMangler::mangleAddressSpaceType(QualType T,
+                                                     Qualifiers Quals,
+                                                     SourceRange Range) {
+  // Address space is mangled as an unqualified templated type in the __clang
+  // namespace. The demangled version of this is:
+  // In the case of a language specific address space:
+  // __clang::struct _AS[language_addr_space]<Type>
+  // where:
+  //  <language_addr_space> ::= <OpenCL-addrspace> | <CUDA-addrspace>
+  //    <OpenCL-addrspace> ::= "CL" [ "global" | "local" | "constant" |
+  //                                "private"| "generic" ]
+  //    <CUDA-addrspace> ::= "CU" [ "device" | "constant" | "shared" ]
+  //    Note that the above were chosen to match the Itanium mangling for this.
+  //
+  // In the case of a non-language specific address space:
+  //  __clang::struct _AS<TargetAS, Type>
+  assert(Quals.hasAddressSpace() && "Not valid without address space");
+  llvm::SmallString<32> ASMangling;
+  llvm::raw_svector_ostream Stream(ASMangling);
+  MicrosoftCXXNameMangler Extra(Context, Stream);
+  Stream << "?$";
+
+  LangAS AS = Quals.getAddressSpace();
+  if (Context.getASTContext().addressSpaceMapManglingFor(AS)) {
+    unsigned TargetAS = Context.getASTContext().getTargetAddressSpace(AS);
+    Extra.mangleSourceName("_AS");
+    Extra.mangleIntegerLiteral(llvm::APSInt::getUnsigned(TargetAS),
+                               /*IsBoolean*/ false);
+  } else {
+    switch (AS) {
+    default:
+      llvm_unreachable("Not a language specific address space");
+    case LangAS::opencl_global:
+      Extra.mangleSourceName("_ASCLglobal");
+      break;
+    case LangAS::opencl_local:
+      Extra.mangleSourceName("_ASCLlocal");
+      break;
+    case LangAS::opencl_constant:
+      Extra.mangleSourceName("_ASCLconstant");
+      break;
+    case LangAS::opencl_private:
+      Extra.mangleSourceName("_ASCLprivate");
+      break;
+    case LangAS::opencl_generic:
+      Extra.mangleSourceName("_ASCLgeneric");
+      break;
+    case LangAS::cuda_device:
+      Extra.mangleSourceName("_ASCUdevice");
+      break;
+    case LangAS::cuda_constant:
+      Extra.mangleSourceName("_ASCUconstant");
+      break;
+    case LangAS::cuda_shared:
+      Extra.mangleSourceName("_ASCUshared");
+      break;
+    case LangAS::ptr32_sptr:
+    case LangAS::ptr32_uptr:
+    case LangAS::ptr64:
+      llvm_unreachable("don't mangle ptr address spaces with _AS");
+    }
+  }
+
+  Extra.mangleType(T, Range, QMM_Escape);
+  mangleQualifiers(Qualifiers(), false);
+  mangleArtificialTagType(TTK_Struct, ASMangling, {"__clang"});
+}
+
+void MicrosoftCXXNameMangler::mangleType(QualType T, SourceRange Range,
+                                         QualifierMangleMode QMM) {
+  // Don't use the canonical types.  MSVC includes things like 'const' on
+  // pointer arguments to function pointers that canonicalization strips away.
+  T = T.getDesugaredType(getASTContext());
+  Qualifiers Quals = T.getLocalQualifiers();
+
+  if (const ArrayType *AT = getASTContext().getAsArrayType(T)) {
+    // If there were any Quals, getAsArrayType() pushed them onto the array
+    // element type.
+    if (QMM == QMM_Mangle)
+      Out << 'A';
+    else if (QMM == QMM_Escape || QMM == QMM_Result)
+      Out << "$$B";
+    mangleArrayType(AT);
+    return;
+  }
+
+  bool IsPointer = T->isAnyPointerType() || T->isMemberPointerType() ||
+                   T->isReferenceType() || T->isBlockPointerType();
+
+  switch (QMM) {
+  case QMM_Drop:
+    if (Quals.hasObjCLifetime())
+      Quals = Quals.withoutObjCLifetime();
+    break;
+  case QMM_Mangle:
+    if (const FunctionType *FT = dyn_cast<FunctionType>(T)) {
+      Out << '6';
+      mangleFunctionType(FT);
+      return;
+    }
+    mangleQualifiers(Quals, false);
+    break;
+  case QMM_Escape:
+    if (!IsPointer && Quals) {
+      Out << "$$C";
+      mangleQualifiers(Quals, false);
+    }
+    break;
+  case QMM_Result:
+    // Presence of __unaligned qualifier shouldn't affect mangling here.
+    Quals.removeUnaligned();
+    if (Quals.hasObjCLifetime())
+      Quals = Quals.withoutObjCLifetime();
+    if ((!IsPointer && Quals) || isa<TagType>(T) || isArtificialTagType(T)) {
+      Out << '?';
+      mangleQualifiers(Quals, false);
+    }
+    break;
+  }
+
+  const Type *ty = T.getTypePtr();
+
+  switch (ty->getTypeClass()) {
+#define ABSTRACT_TYPE(CLASS, PARENT)
+#define NON_CANONICAL_TYPE(CLASS, PARENT) \
+  case Type::CLASS: \
+    llvm_unreachable("can't mangle non-canonical type " #CLASS "Type"); \
+    return;
+#define TYPE(CLASS, PARENT) \
+  case Type::CLASS: \
+    mangleType(cast<CLASS##Type>(ty), Quals, Range); \
+    break;
+#include "clang/AST/TypeNodes.inc"
+#undef ABSTRACT_TYPE
+#undef NON_CANONICAL_TYPE
+#undef TYPE
+  }
+}
+
+void MicrosoftCXXNameMangler::mangleType(const BuiltinType *T, Qualifiers,
+                                         SourceRange Range) {
+  //  <type>         ::= <builtin-type>
+  //  <builtin-type> ::= X  # void
+  //                 ::= C  # signed char
+  //                 ::= D  # char
+  //                 ::= E  # unsigned char
+  //                 ::= F  # short
+  //                 ::= G  # unsigned short (or wchar_t if it's not a builtin)
+  //                 ::= H  # int
+  //                 ::= I  # unsigned int
+  //                 ::= J  # long
+  //                 ::= K  # unsigned long
+  //                     L  # <none>
+  //                 ::= M  # float
+  //                 ::= N  # double
+  //                 ::= O  # long double (__float80 is mangled differently)
+  //                 ::= _J # long long, __int64
+  //                 ::= _K # unsigned long long, __int64
+  //                 ::= _L # __int128
+  //                 ::= _M # unsigned __int128
+  //                 ::= _N # bool
+  //                     _O # <array in parameter>
+  //                 ::= _Q # char8_t
+  //                 ::= _S # char16_t
+  //                 ::= _T # __float80 (Intel)
+  //                 ::= _U # char32_t
+  //                 ::= _W # wchar_t
+  //                 ::= _Z # __float80 (Digital Mars)
+  switch (T->getKind()) {
+  case BuiltinType::Void:
+    Out << 'X';
+    break;
+  case BuiltinType::SChar:
+    Out << 'C';
+    break;
+  case BuiltinType::Char_U:
+  case BuiltinType::Char_S:
+    Out << 'D';
+    break;
+  case BuiltinType::UChar:
+    Out << 'E';
+    break;
+  case BuiltinType::Short:
+    Out << 'F';
+    break;
+  case BuiltinType::UShort:
+    Out << 'G';
+    break;
+  case BuiltinType::Int:
+    Out << 'H';
+    break;
+  case BuiltinType::UInt:
+    Out << 'I';
+    break;
+  case BuiltinType::Long:
+    Out << 'J';
+    break;
+  case BuiltinType::ULong:
+    Out << 'K';
+    break;
+  case BuiltinType::Float:
+    Out << 'M';
+    break;
+  case BuiltinType::Double:
+    Out << 'N';
+    break;
+  // TODO: Determine size and mangle accordingly
+  case BuiltinType::LongDouble:
+    Out << 'O';
+    break;
+  case BuiltinType::LongLong:
+    Out << "_J";
+    break;
+  case BuiltinType::ULongLong:
+    Out << "_K";
+    break;
+  case BuiltinType::Int128:
+    Out << "_L";
+    break;
+  case BuiltinType::UInt128:
+    Out << "_M";
+    break;
+  case BuiltinType::Bool:
+    Out << "_N";
+    break;
+  case BuiltinType::Char8:
+    Out << "_Q";
+    break;
+  case BuiltinType::Char16:
+    Out << "_S";
+    break;
+  case BuiltinType::Char32:
+    Out << "_U";
+    break;
+  case BuiltinType::WChar_S:
+  case BuiltinType::WChar_U:
+    Out << "_W";
+    break;
+
+#define BUILTIN_TYPE(Id, SingletonId)
+#define PLACEHOLDER_TYPE(Id, SingletonId) \
+  case BuiltinType::Id:
+#include "clang/AST/BuiltinTypes.def"
+  case BuiltinType::Dependent:
+    llvm_unreachable("placeholder types shouldn't get to name mangling");
+
+  case BuiltinType::ObjCId:
+    mangleArtificialTagType(TTK_Struct, "objc_object");
+    break;
+  case BuiltinType::ObjCClass:
+    mangleArtificialTagType(TTK_Struct, "objc_class");
+    break;
+  case BuiltinType::ObjCSel:
+    mangleArtificialTagType(TTK_Struct, "objc_selector");
+    break;
+
+#define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
+  case BuiltinType::Id: \
+    Out << "PAUocl_" #ImgType "_" #Suffix "@@"; \
+    break;
+#include "clang/Basic/OpenCLImageTypes.def"
+  case BuiltinType::OCLSampler:
+    Out << "PA";
+    mangleArtificialTagType(TTK_Struct, "ocl_sampler");
+    break;
+  case BuiltinType::OCLEvent:
+    Out << "PA";
+    mangleArtificialTagType(TTK_Struct, "ocl_event");
+    break;
+  case BuiltinType::OCLClkEvent:
+    Out << "PA";
+    mangleArtificialTagType(TTK_Struct, "ocl_clkevent");
+    break;
+  case BuiltinType::OCLQueue:
+    Out << "PA";
+    mangleArtificialTagType(TTK_Struct, "ocl_queue");
+    break;
+  case BuiltinType::OCLReserveID:
+    Out << "PA";
+    mangleArtificialTagType(TTK_Struct, "ocl_reserveid");
+    break;
+#define EXT_OPAQUE_TYPE(ExtType, Id, Ext) \
+  case BuiltinType::Id: \
+    mangleArtificialTagType(TTK_Struct, "ocl_" #ExtType); \
+    break;
+#include "clang/Basic/OpenCLExtensionTypes.def"
+
+  case BuiltinType::NullPtr:
+    Out << "$$T";
+    break;
+
+  case BuiltinType::Float16:
+    mangleArtificialTagType(TTK_Struct, "_Float16", {"__clang"});
+    break;
+
+  case BuiltinType::Half:
+    mangleArtificialTagType(TTK_Struct, "_Half", {"__clang"});
+    break;
+
+#define SVE_TYPE(Name, Id, SingletonId) \
+  case BuiltinType::Id:
+#include "clang/Basic/AArch64SVEACLETypes.def"
+  case BuiltinType::ShortAccum:
+  case BuiltinType::Accum:
+  case BuiltinType::LongAccum:
+  case BuiltinType::UShortAccum:
+  case BuiltinType::UAccum:
+  case BuiltinType::ULongAccum:
+  case BuiltinType::ShortFract:
+  case BuiltinType::Fract:
+  case BuiltinType::LongFract:
+  case BuiltinType::UShortFract:
+  case BuiltinType::UFract:
+  case BuiltinType::ULongFract:
+  case BuiltinType::SatShortAccum:
+  case BuiltinType::SatAccum:
+  case BuiltinType::SatLongAccum:
+  case BuiltinType::SatUShortAccum:
+  case BuiltinType::SatUAccum:
+  case BuiltinType::SatULongAccum:
+  case BuiltinType::SatShortFract:
+  case BuiltinType::SatFract:
+  case BuiltinType::SatLongFract:
+  case BuiltinType::SatUShortFract:
+  case BuiltinType::SatUFract:
+  case BuiltinType::SatULongFract:
+  case BuiltinType::Float128: {
+    DiagnosticsEngine &Diags = Context.getDiags();
+    unsigned DiagID = Diags.getCustomDiagID(
+        DiagnosticsEngine::Error, "cannot mangle this built-in %0 type yet");
+    Diags.Report(Range.getBegin(), DiagID)
+        << T->getName(Context.getASTContext().getPrintingPolicy()) << Range;
+    break;
+  }
+  }
+}
+
+// <type>          ::= <function-type>
+void MicrosoftCXXNameMangler::mangleType(const FunctionProtoType *T, Qualifiers,
+                                         SourceRange) {
+  // Structors only appear in decls, so at this point we know it's not a
+  // structor type.
+  // FIXME: This may not be lambda-friendly.
+  if (T->getMethodQuals() || T->getRefQualifier() != RQ_None) {
+    Out << "$$A8@@";
+    mangleFunctionType(T, /*D=*/nullptr, /*ForceThisQuals=*/true);
+  } else {
+    Out << "$$A6";
+    mangleFunctionType(T);
+  }
+}
+void MicrosoftCXXNameMangler::mangleType(const FunctionNoProtoType *T,
+                                         Qualifiers, SourceRange) {
+  Out << "$$A6";
+  mangleFunctionType(T);
+}
+
+void MicrosoftCXXNameMangler::mangleFunctionType(const FunctionType *T,
+                                                 const FunctionDecl *D,
+                                                 bool ForceThisQuals,
+                                                 bool MangleExceptionSpec) {
+  // <function-type> ::= <this-cvr-qualifiers> <calling-convention>
+  //                     <return-type> <argument-list> <throw-spec>
+  const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(T);
+
+  SourceRange Range;
+  if (D) Range = D->getSourceRange();
+
+  bool IsInLambda = false;
+  bool IsStructor = false, HasThisQuals = ForceThisQuals, IsCtorClosure = false;
+  CallingConv CC = T->getCallConv();
+  if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(D)) {
+    if (MD->getParent()->isLambda())
+      IsInLambda = true;
+    if (MD->isInstance())
+      HasThisQuals = true;
+    if (isa<CXXDestructorDecl>(MD)) {
+      IsStructor = true;
+    } else if (isa<CXXConstructorDecl>(MD)) {
+      IsStructor = true;
+      IsCtorClosure = (StructorType == Ctor_CopyingClosure ||
+                       StructorType == Ctor_DefaultClosure) &&
+                      isStructorDecl(MD);
+      if (IsCtorClosure)
+        CC = getASTContext().getDefaultCallingConvention(
+            /*IsVariadic=*/false, /*IsCXXMethod=*/true);
+    }
+  }
+
+  // If this is a C++ instance method, mangle the CVR qualifiers for the
+  // this pointer.
+  if (HasThisQuals) {
+    Qualifiers Quals = Proto->getMethodQuals();
+    manglePointerExtQualifiers(Quals, /*PointeeType=*/QualType());
+    mangleRefQualifier(Proto->getRefQualifier());
+    mangleQualifiers(Quals, /*IsMember=*/false);
+  }
+
+  mangleCallingConvention(CC);
+
+  // <return-type> ::= <type>
+  //               ::= @ # structors (they have no declared return type)
+  if (IsStructor) {
+    if (isa<CXXDestructorDecl>(D) && isStructorDecl(D)) {
+      // The scalar deleting destructor takes an extra int argument which is not
+      // reflected in the AST.
+      if (StructorType == Dtor_Deleting) {
+        Out << (PointersAre64Bit ? "PEAXI@Z" : "PAXI@Z");
+        return;
+      }
+      // The vbase destructor returns void which is not reflected in the AST.
+      if (StructorType == Dtor_Complete) {
+        Out << "XXZ";
+        return;
+      }
+    }
+    if (IsCtorClosure) {
+      // Default constructor closure and copy constructor closure both return
+      // void.
+      Out << 'X';
+
+      if (StructorType == Ctor_DefaultClosure) {
+        // Default constructor closure always has no arguments.
+        Out << 'X';
+      } else if (StructorType == Ctor_CopyingClosure) {
+        // Copy constructor closure always takes an unqualified reference.
+        mangleFunctionArgumentType(getASTContext().getLValueReferenceType(
+                                       Proto->getParamType(0)
+                                           ->getAs<LValueReferenceType>()
+                                           ->getPointeeType(),
+                                       /*SpelledAsLValue=*/true),
+                                   Range);
+        Out << '@';
+      } else {
+        llvm_unreachable("unexpected constructor closure!");
+      }
+      Out << 'Z';
+      return;
+    }
+    Out << '@';
+  } else {
+    QualType ResultType = T->getReturnType();
+    if (const auto *AT =
+            dyn_cast_or_null<AutoType>(ResultType->getContainedAutoType())) {
+      Out << '?';
+      mangleQualifiers(ResultType.getLocalQualifiers(), /*IsMember=*/false);
+      Out << '?';
+      assert(AT->getKeyword() != AutoTypeKeyword::GNUAutoType &&
+             "shouldn't need to mangle __auto_type!");
+      mangleSourceName(AT->isDecltypeAuto() ? "<decltype-auto>" : "<auto>");
+      Out << '@';
+    } else if (IsInLambda) {
+      Out << '@';
+    } else {
+      if (ResultType->isVoidType())
+        ResultType = ResultType.getUnqualifiedType();
+      mangleType(ResultType, Range, QMM_Result);
+    }
+  }
+
+  // <argument-list> ::= X # void
+  //                 ::= <type>+ @
+  //                 ::= <type>* Z # varargs
+  if (!Proto) {
+    // Function types without prototypes can arise when mangling a function type
+    // within an overloadable function in C. We mangle these as the absence of
+    // any parameter types (not even an empty parameter list).
+    Out << '@';
+  } else if (Proto->getNumParams() == 0 && !Proto->isVariadic()) {
+    Out << 'X';
+  } else {
+    // Happens for function pointer type arguments for example.
+    for (unsigned I = 0, E = Proto->getNumParams(); I != E; ++I) {
+      mangleFunctionArgumentType(Proto->getParamType(I), Range);
+      // Mangle each pass_object_size parameter as if it's a parameter of enum
+      // type passed directly after the parameter with the pass_object_size
+      // attribute. The aforementioned enum's name is __pass_object_size, and we
+      // pretend it resides in a top-level namespace called __clang.
+      //
+      // FIXME: Is there a defined extension notation for the MS ABI, or is it
+      // necessary to just cross our fingers and hope this type+namespace
+      // combination doesn't conflict with anything?
+      if (D)
+        if (const auto *P = D->getParamDecl(I)->getAttr<PassObjectSizeAttr>())
+          manglePassObjectSizeArg(P);
+    }
+    // <builtin-type>      ::= Z  # ellipsis
+    if (Proto->isVariadic())
+      Out << 'Z';
+    else
+      Out << '@';
+  }
+
+  if (MangleExceptionSpec && getASTContext().getLangOpts().CPlusPlus17 &&
+      getASTContext().getLangOpts().isCompatibleWithMSVC(
+          LangOptions::MSVC2017_5))
+    mangleThrowSpecification(Proto);
+  else
+    Out << 'Z';
+}
+
+void MicrosoftCXXNameMangler::mangleFunctionClass(const FunctionDecl *FD) {
+  // <function-class>  ::= <member-function> E? # E designates a 64-bit 'this'
+  //                                            # pointer. in 64-bit mode *all*
+  //                                            # 'this' pointers are 64-bit.
+  //                   ::= <global-function>
+  // <member-function> ::= A # private: near
+  //                   ::= B # private: far
+  //                   ::= C # private: static near
+  //                   ::= D # private: static far
+  //                   ::= E # private: virtual near
+  //                   ::= F # private: virtual far
+  //                   ::= I # protected: near
+  //                   ::= J # protected: far
+  //                   ::= K # protected: static near
+  //                   ::= L # protected: static far
+  //                   ::= M # protected: virtual near
+  //                   ::= N # protected: virtual far
+  //                   ::= Q # public: near
+  //                   ::= R # public: far
+  //                   ::= S # public: static near
+  //                   ::= T # public: static far
+  //                   ::= U # public: virtual near
+  //                   ::= V # public: virtual far
+  // <global-function> ::= Y # global near
+  //                   ::= Z # global far
+  if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
+    bool IsVirtual = MD->isVirtual();
+    // When mangling vbase destructor variants, ignore whether or not the
+    // underlying destructor was defined to be virtual.
+    if (isa<CXXDestructorDecl>(MD) && isStructorDecl(MD) &&
+        StructorType == Dtor_Complete) {
+      IsVirtual = false;
+    }
+    switch (MD->getAccess()) {
+      case AS_none:
+        llvm_unreachable("Unsupported access specifier");
+      case AS_private:
+        if (MD->isStatic())
+          Out << 'C';
+        else if (IsVirtual)
+          Out << 'E';
+        else
+          Out << 'A';
+        break;
+      case AS_protected:
+        if (MD->isStatic())
+          Out << 'K';
+        else if (IsVirtual)
+          Out << 'M';
+        else
+          Out << 'I';
+        break;
+      case AS_public:
+        if (MD->isStatic())
+          Out << 'S';
+        else if (IsVirtual)
+          Out << 'U';
+        else
+          Out << 'Q';
+    }
+  } else {
+    Out << 'Y';
+  }
+}
+void MicrosoftCXXNameMangler::mangleCallingConvention(CallingConv CC) {
+  // <calling-convention> ::= A # __cdecl
+  //                      ::= B # __export __cdecl
+  //                      ::= C # __pascal
+  //                      ::= D # __export __pascal
+  //                      ::= E # __thiscall
+  //                      ::= F # __export __thiscall
+  //                      ::= G # __stdcall
+  //                      ::= H # __export __stdcall
+  //                      ::= I # __fastcall
+  //                      ::= J # __export __fastcall
+  //                      ::= Q # __vectorcall
+  //                      ::= w # __regcall
+  // The 'export' calling conventions are from a bygone era
+  // (*cough*Win16*cough*) when functions were declared for export with
+  // that keyword. (It didn't actually export them, it just made them so
+  // that they could be in a DLL and somebody from another module could call
+  // them.)
+
+  switch (CC) {
+    default:
+      llvm_unreachable("Unsupported CC for mangling");
+    case CC_Win64:
+    case CC_X86_64SysV:
+    case CC_C: Out << 'A'; break;
+    case CC_X86Pascal: Out << 'C'; break;
+    case CC_X86ThisCall: Out << 'E'; break;
+    case CC_X86StdCall: Out << 'G'; break;
+    case CC_X86FastCall: Out << 'I'; break;
+    case CC_X86VectorCall: Out << 'Q'; break;
+    case CC_Swift: Out << 'S'; break;
+    case CC_PreserveMost: Out << 'U'; break;
+    case CC_X86RegCall: Out << 'w'; break;
+  }
+}
+void MicrosoftCXXNameMangler::mangleCallingConvention(const FunctionType *T) {
+  mangleCallingConvention(T->getCallConv());
+}
+
+void MicrosoftCXXNameMangler::mangleThrowSpecification(
+                                                const FunctionProtoType *FT) {
+  // <throw-spec> ::= Z # (default)
+  //              ::= _E # noexcept
+  if (FT->canThrow())
+    Out << 'Z';
+  else
+    Out << "_E";
+}
+
+void MicrosoftCXXNameMangler::mangleType(const UnresolvedUsingType *T,
+                                         Qualifiers, SourceRange Range) {
+  // Probably should be mangled as a template instantiation; need to see what
+  // VC does first.
+  DiagnosticsEngine &Diags = Context.getDiags();
+  unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
+    "cannot mangle this unresolved dependent type yet");
+  Diags.Report(Range.getBegin(), DiagID)
+    << Range;
+}
+
+// <type>        ::= <union-type> | <struct-type> | <class-type> | <enum-type>
+// <union-type>  ::= T <name>
+// <struct-type> ::= U <name>
+// <class-type>  ::= V <name>
+// <enum-type>   ::= W4 <name>
+void MicrosoftCXXNameMangler::mangleTagTypeKind(TagTypeKind TTK) {
+  switch (TTK) {
+    case TTK_Union:
+      Out << 'T';
+      break;
+    case TTK_Struct:
+    case TTK_Interface:
+      Out << 'U';
+      break;
+    case TTK_Class:
+      Out << 'V';
+      break;
+    case TTK_Enum:
+      Out << "W4";
+      break;
+  }
+}
+void MicrosoftCXXNameMangler::mangleType(const EnumType *T, Qualifiers,
+                                         SourceRange) {
+  mangleType(cast<TagType>(T)->getDecl());
+}
+void MicrosoftCXXNameMangler::mangleType(const RecordType *T, Qualifiers,
+                                         SourceRange) {
+  mangleType(cast<TagType>(T)->getDecl());
+}
+void MicrosoftCXXNameMangler::mangleType(const TagDecl *TD) {
+  mangleTagTypeKind(TD->getTagKind());
+  mangleName(TD);
+}
+
+// If you add a call to this, consider updating isArtificialTagType() too.
+void MicrosoftCXXNameMangler::mangleArtificialTagType(
+    TagTypeKind TK, StringRef UnqualifiedName,
+    ArrayRef<StringRef> NestedNames) {
+  // <name> ::= <unscoped-name> {[<named-scope>]+ | [<nested-name>]}? @
+  mangleTagTypeKind(TK);
+
+  // Always start with the unqualified name.
+  mangleSourceName(UnqualifiedName);
+
+  for (auto I = NestedNames.rbegin(), E = NestedNames.rend(); I != E; ++I)
+    mangleSourceName(*I);
+
+  // Terminate the whole name with an '@'.
+  Out << '@';
+}
+
+// <type>       ::= <array-type>
+// <array-type> ::= <pointer-cvr-qualifiers> <cvr-qualifiers>
+//                  [Y <dimension-count> <dimension>+]
+//                  <element-type> # as global, E is never required
+// It's supposed to be the other way around, but for some strange reason, it
+// isn't. Today this behavior is retained for the sole purpose of backwards
+// compatibility.
+void MicrosoftCXXNameMangler::mangleDecayedArrayType(const ArrayType *T) {
+  // This isn't a recursive mangling, so now we have to do it all in this
+  // one call.
+  manglePointerCVQualifiers(T->getElementType().getQualifiers());
+  mangleType(T->getElementType(), SourceRange());
+}
+void MicrosoftCXXNameMangler::mangleType(const ConstantArrayType *T, Qualifiers,
+                                         SourceRange) {
+  llvm_unreachable("Should have been special cased");
+}
+void MicrosoftCXXNameMangler::mangleType(const VariableArrayType *T, Qualifiers,
+                                         SourceRange) {
+  llvm_unreachable("Should have been special cased");
+}
+void MicrosoftCXXNameMangler::mangleType(const DependentSizedArrayType *T,
+                                         Qualifiers, SourceRange) {
+  llvm_unreachable("Should have been special cased");
+}
+void MicrosoftCXXNameMangler::mangleType(const IncompleteArrayType *T,
+                                         Qualifiers, SourceRange) {
+  llvm_unreachable("Should have been special cased");
+}
+void MicrosoftCXXNameMangler::mangleArrayType(const ArrayType *T) {
+  QualType ElementTy(T, 0);
+  SmallVector<llvm::APInt, 3> Dimensions;
+  for (;;) {
+    if (ElementTy->isConstantArrayType()) {
+      const ConstantArrayType *CAT =
+          getASTContext().getAsConstantArrayType(ElementTy);
+      Dimensions.push_back(CAT->getSize());
+      ElementTy = CAT->getElementType();
+    } else if (ElementTy->isIncompleteArrayType()) {
+      const IncompleteArrayType *IAT =
+          getASTContext().getAsIncompleteArrayType(ElementTy);
+      Dimensions.push_back(llvm::APInt(32, 0));
+      ElementTy = IAT->getElementType();
+    } else if (ElementTy->isVariableArrayType()) {
+      const VariableArrayType *VAT =
+        getASTContext().getAsVariableArrayType(ElementTy);
+      Dimensions.push_back(llvm::APInt(32, 0));
+      ElementTy = VAT->getElementType();
+    } else if (ElementTy->isDependentSizedArrayType()) {
+      // The dependent expression has to be folded into a constant (TODO).
+      const DependentSizedArrayType *DSAT =
+        getASTContext().getAsDependentSizedArrayType(ElementTy);
+      DiagnosticsEngine &Diags = Context.getDiags();
+      unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
+        "cannot mangle this dependent-length array yet");
+      Diags.Report(DSAT->getSizeExpr()->getExprLoc(), DiagID)
+        << DSAT->getBracketsRange();
+      return;
+    } else {
+      break;
+    }
+  }
+  Out << 'Y';
+  // <dimension-count> ::= <number> # number of extra dimensions
+  mangleNumber(Dimensions.size());
+  for (const llvm::APInt &Dimension : Dimensions)
+    mangleNumber(Dimension.getLimitedValue());
+  mangleType(ElementTy, SourceRange(), QMM_Escape);
+}
+
+// <type>                   ::= <pointer-to-member-type>
+// <pointer-to-member-type> ::= <pointer-cvr-qualifiers> <cvr-qualifiers>
+//                                                          <class name> <type>
+void MicrosoftCXXNameMangler::mangleType(const MemberPointerType *T,
+                                         Qualifiers Quals, SourceRange Range) {
+  QualType PointeeType = T->getPointeeType();
+  manglePointerCVQualifiers(Quals);
+  manglePointerExtQualifiers(Quals, PointeeType);
+  if (const FunctionProtoType *FPT = PointeeType->getAs<FunctionProtoType>()) {
+    Out << '8';
+    mangleName(T->getClass()->castAs<RecordType>()->getDecl());
+    mangleFunctionType(FPT, nullptr, true);
+  } else {
+    mangleQualifiers(PointeeType.getQualifiers(), true);
+    mangleName(T->getClass()->castAs<RecordType>()->getDecl());
+    mangleType(PointeeType, Range, QMM_Drop);
+  }
+}
+
+void MicrosoftCXXNameMangler::mangleType(const TemplateTypeParmType *T,
+                                         Qualifiers, SourceRange Range) {
+  DiagnosticsEngine &Diags = Context.getDiags();
+  unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
+    "cannot mangle this template type parameter type yet");
+  Diags.Report(Range.getBegin(), DiagID)
+    << Range;
+}
+
+void MicrosoftCXXNameMangler::mangleType(const SubstTemplateTypeParmPackType *T,
+                                         Qualifiers, SourceRange Range) {
+  DiagnosticsEngine &Diags = Context.getDiags();
+  unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
+    "cannot mangle this substituted parameter pack yet");
+  Diags.Report(Range.getBegin(), DiagID)
+    << Range;
+}
+
+// <type> ::= <pointer-type>
+// <pointer-type> ::= E? <pointer-cvr-qualifiers> <cvr-qualifiers> <type>
+//                       # the E is required for 64-bit non-static pointers
+void MicrosoftCXXNameMangler::mangleType(const PointerType *T, Qualifiers Quals,
+                                         SourceRange Range) {
+  QualType PointeeType = T->getPointeeType();
+  manglePointerCVQualifiers(Quals);
+  manglePointerExtQualifiers(Quals, PointeeType);
+
+  // For pointer size address spaces, go down the same type mangling path as
+  // non address space types.
+  LangAS AddrSpace = PointeeType.getQualifiers().getAddressSpace();
+  if (isPtrSizeAddressSpace(AddrSpace) || AddrSpace == LangAS::Default)
+    mangleType(PointeeType, Range);
+  else
+    mangleAddressSpaceType(PointeeType, PointeeType.getQualifiers(), Range);
+}
+
+void MicrosoftCXXNameMangler::mangleType(const ObjCObjectPointerType *T,
+                                         Qualifiers Quals, SourceRange Range) {
+  QualType PointeeType = T->getPointeeType();
+  switch (Quals.getObjCLifetime()) {
+  case Qualifiers::OCL_None:
+  case Qualifiers::OCL_ExplicitNone:
+    break;
+  case Qualifiers::OCL_Autoreleasing:
+  case Qualifiers::OCL_Strong:
+  case Qualifiers::OCL_Weak:
+    return mangleObjCLifetime(PointeeType, Quals, Range);
+  }
+  manglePointerCVQualifiers(Quals);
+  manglePointerExtQualifiers(Quals, PointeeType);
+  mangleType(PointeeType, Range);
+}
+
+// <type> ::= <reference-type>
+// <reference-type> ::= A E? <cvr-qualifiers> <type>
+//                 # the E is required for 64-bit non-static lvalue references
+void MicrosoftCXXNameMangler::mangleType(const LValueReferenceType *T,
+                                         Qualifiers Quals, SourceRange Range) {
+  QualType PointeeType = T->getPointeeType();
+  assert(!Quals.hasConst() && !Quals.hasVolatile() && "unexpected qualifier!");
+  Out << 'A';
+  manglePointerExtQualifiers(Quals, PointeeType);
+  mangleType(PointeeType, Range);
+}
+
+// <type> ::= <r-value-reference-type>
+// <r-value-reference-type> ::= $$Q E? <cvr-qualifiers> <type>
+//                 # the E is required for 64-bit non-static rvalue references
+void MicrosoftCXXNameMangler::mangleType(const RValueReferenceType *T,
+                                         Qualifiers Quals, SourceRange Range) {
+  QualType PointeeType = T->getPointeeType();
+  assert(!Quals.hasConst() && !Quals.hasVolatile() && "unexpected qualifier!");
+  Out << "$$Q";
+  manglePointerExtQualifiers(Quals, PointeeType);
+  mangleType(PointeeType, Range);
+}
+
+void MicrosoftCXXNameMangler::mangleType(const ComplexType *T, Qualifiers,
+                                         SourceRange Range) {
+  QualType ElementType = T->getElementType();
+
+  llvm::SmallString<64> TemplateMangling;
+  llvm::raw_svector_ostream Stream(TemplateMangling);
+  MicrosoftCXXNameMangler Extra(Context, Stream);
+  Stream << "?$";
+  Extra.mangleSourceName("_Complex");
+  Extra.mangleType(ElementType, Range, QMM_Escape);
+
+  mangleArtificialTagType(TTK_Struct, TemplateMangling, {"__clang"});
+}
+
+// Returns true for types that mangleArtificialTagType() gets called for with
+// TTK_Union, TTK_Struct, TTK_Class and where compatibility with MSVC's
+// mangling matters.
+// (It doesn't matter for Objective-C types and the like that cl.exe doesn't
+// support.)
+bool MicrosoftCXXNameMangler::isArtificialTagType(QualType T) const {
+  const Type *ty = T.getTypePtr();
+  switch (ty->getTypeClass()) {
+  default:
+    return false;
+
+  case Type::Vector: {
+    // For ABI compatibility only __m64, __m128(id), and __m256(id) matter,
+    // but since mangleType(VectorType*) always calls mangleArtificialTagType()
+    // just always return true (the other vector types are clang-only).
+    return true;
+  }
+  }
+}
+
+void MicrosoftCXXNameMangler::mangleType(const VectorType *T, Qualifiers Quals,
+                                         SourceRange Range) {
+  const BuiltinType *ET = T->getElementType()->getAs<BuiltinType>();
+  assert(ET && "vectors with non-builtin elements are unsupported");
+  uint64_t Width = getASTContext().getTypeSize(T);
+  // Pattern match exactly the typedefs in our intrinsic headers.  Anything that
+  // doesn't match the Intel types uses a custom mangling below.
+  size_t OutSizeBefore = Out.tell();
+  if (!isa<ExtVectorType>(T)) {
+    if (getASTContext().getTargetInfo().getTriple().isX86()) {
+      if (Width == 64 && ET->getKind() == BuiltinType::LongLong) {
+        mangleArtificialTagType(TTK_Union, "__m64");
+      } else if (Width >= 128) {
+        if (ET->getKind() == BuiltinType::Float)
+          mangleArtificialTagType(TTK_Union, "__m" + llvm::utostr(Width));
+        else if (ET->getKind() == BuiltinType::LongLong)
+          mangleArtificialTagType(TTK_Union, "__m" + llvm::utostr(Width) + 'i');
+        else if (ET->getKind() == BuiltinType::Double)
+          mangleArtificialTagType(TTK_Struct, "__m" + llvm::utostr(Width) + 'd');
+      }
+    }
+  }
+
+  bool IsBuiltin = Out.tell() != OutSizeBefore;
+  if (!IsBuiltin) {
+    // The MS ABI doesn't have a special mangling for vector types, so we define
+    // our own mangling to handle uses of __vector_size__ on user-specified
+    // types, and for extensions like __v4sf.
+
+    llvm::SmallString<64> TemplateMangling;
+    llvm::raw_svector_ostream Stream(TemplateMangling);
+    MicrosoftCXXNameMangler Extra(Context, Stream);
+    Stream << "?$";
+    Extra.mangleSourceName("__vector");
+    Extra.mangleType(QualType(ET, 0), Range, QMM_Escape);
+    Extra.mangleIntegerLiteral(llvm::APSInt::getUnsigned(T->getNumElements()),
+                               /*IsBoolean=*/false);
+
+    mangleArtificialTagType(TTK_Union, TemplateMangling, {"__clang"});
+  }
+}
+
+void MicrosoftCXXNameMangler::mangleType(const ExtVectorType *T,
+                                         Qualifiers Quals, SourceRange Range) {
+  mangleType(static_cast<const VectorType *>(T), Quals, Range);
+}
+
+void MicrosoftCXXNameMangler::mangleType(const DependentVectorType *T,
+                                         Qualifiers, SourceRange Range) {
+  DiagnosticsEngine &Diags = Context.getDiags();
+  unsigned DiagID = Diags.getCustomDiagID(
+      DiagnosticsEngine::Error,
+      "cannot mangle this dependent-sized vector type yet");
+  Diags.Report(Range.getBegin(), DiagID) << Range;
+}
+
+void MicrosoftCXXNameMangler::mangleType(const DependentSizedExtVectorType *T,
+                                         Qualifiers, SourceRange Range) {
+  DiagnosticsEngine &Diags = Context.getDiags();
+  unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
+    "cannot mangle this dependent-sized extended vector type yet");
+  Diags.Report(Range.getBegin(), DiagID)
+    << Range;
+}
+
+void MicrosoftCXXNameMangler::mangleType(const DependentAddressSpaceType *T,
+                                         Qualifiers, SourceRange Range) {
+  DiagnosticsEngine &Diags = Context.getDiags();
+  unsigned DiagID = Diags.getCustomDiagID(
+      DiagnosticsEngine::Error,
+      "cannot mangle this dependent address space type yet");
+  Diags.Report(Range.getBegin(), DiagID) << Range;
+}
+
+void MicrosoftCXXNameMangler::mangleType(const ObjCInterfaceType *T, Qualifiers,
+                                         SourceRange) {
+  // ObjC interfaces have structs underlying them.
+  mangleTagTypeKind(TTK_Struct);
+  mangleName(T->getDecl());
+}
+
+void MicrosoftCXXNameMangler::mangleType(const ObjCObjectType *T,
+                                         Qualifiers Quals, SourceRange Range) {
+  if (T->isKindOfType())
+    return mangleObjCKindOfType(T, Quals, Range);
+
+  if (T->qual_empty() && !T->isSpecialized())
+    return mangleType(T->getBaseType(), Range, QMM_Drop);
+
+  ArgBackRefMap OuterFunArgsContext;
+  ArgBackRefMap OuterTemplateArgsContext;
+  BackRefVec OuterTemplateContext;
+
+  FunArgBackReferences.swap(OuterFunArgsContext);
+  TemplateArgBackReferences.swap(OuterTemplateArgsContext);
+  NameBackReferences.swap(OuterTemplateContext);
+
+  mangleTagTypeKind(TTK_Struct);
+
+  Out << "?$";
+  if (T->isObjCId())
+    mangleSourceName("objc_object");
+  else if (T->isObjCClass())
+    mangleSourceName("objc_class");
+  else
+    mangleSourceName(T->getInterface()->getName());
+
+  for (const auto &Q : T->quals())
+    mangleObjCProtocol(Q);
+
+  if (T->isSpecialized())
+    for (const auto &TA : T->getTypeArgs())
+      mangleType(TA, Range, QMM_Drop);
+
+  Out << '@';
+
+  Out << '@';
+
+  FunArgBackReferences.swap(OuterFunArgsContext);
+  TemplateArgBackReferences.swap(OuterTemplateArgsContext);
+  NameBackReferences.swap(OuterTemplateContext);
+}
+
+void MicrosoftCXXNameMangler::mangleType(const BlockPointerType *T,
+                                         Qualifiers Quals, SourceRange Range) {
+  QualType PointeeType = T->getPointeeType();
+  manglePointerCVQualifiers(Quals);
+  manglePointerExtQualifiers(Quals, PointeeType);
+
+  Out << "_E";
+
+  mangleFunctionType(PointeeType->castAs<FunctionProtoType>());
+}
+
+void MicrosoftCXXNameMangler::mangleType(const InjectedClassNameType *,
+                                         Qualifiers, SourceRange) {
+  llvm_unreachable("Cannot mangle injected class name type.");
+}
+
+void MicrosoftCXXNameMangler::mangleType(const TemplateSpecializationType *T,
+                                         Qualifiers, SourceRange Range) {
+  DiagnosticsEngine &Diags = Context.getDiags();
+  unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
+    "cannot mangle this template specialization type yet");
+  Diags.Report(Range.getBegin(), DiagID)
+    << Range;
+}
+
+void MicrosoftCXXNameMangler::mangleType(const DependentNameType *T, Qualifiers,
+                                         SourceRange Range) {
+  DiagnosticsEngine &Diags = Context.getDiags();
+  unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
+    "cannot mangle this dependent name type yet");
+  Diags.Report(Range.getBegin(), DiagID)
+    << Range;
+}
+
+void MicrosoftCXXNameMangler::mangleType(
+    const DependentTemplateSpecializationType *T, Qualifiers,
+    SourceRange Range) {
+  DiagnosticsEngine &Diags = Context.getDiags();
+  unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
+    "cannot mangle this dependent template specialization type yet");
+  Diags.Report(Range.getBegin(), DiagID)
+    << Range;
+}
+
+void MicrosoftCXXNameMangler::mangleType(const PackExpansionType *T, Qualifiers,
+                                         SourceRange Range) {
+  DiagnosticsEngine &Diags = Context.getDiags();
+  unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
+    "cannot mangle this pack expansion yet");
+  Diags.Report(Range.getBegin(), DiagID)
+    << Range;
+}
+
+void MicrosoftCXXNameMangler::mangleType(const TypeOfType *T, Qualifiers,
+                                         SourceRange Range) {
+  DiagnosticsEngine &Diags = Context.getDiags();
+  unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
+    "cannot mangle this typeof(type) yet");
+  Diags.Report(Range.getBegin(), DiagID)
+    << Range;
+}
+
+void MicrosoftCXXNameMangler::mangleType(const TypeOfExprType *T, Qualifiers,
+                                         SourceRange Range) {
+  DiagnosticsEngine &Diags = Context.getDiags();
+  unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
+    "cannot mangle this typeof(expression) yet");
+  Diags.Report(Range.getBegin(), DiagID)
+    << Range;
+}
+
+void MicrosoftCXXNameMangler::mangleType(const DecltypeType *T, Qualifiers,
+                                         SourceRange Range) {
+  DiagnosticsEngine &Diags = Context.getDiags();
+  unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
+    "cannot mangle this decltype() yet");
+  Diags.Report(Range.getBegin(), DiagID)
+    << Range;
+}
+
+void MicrosoftCXXNameMangler::mangleType(const UnaryTransformType *T,
+                                         Qualifiers, SourceRange Range) {
+  DiagnosticsEngine &Diags = Context.getDiags();
+  unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
+    "cannot mangle this unary transform type yet");
+  Diags.Report(Range.getBegin(), DiagID)
+    << Range;
+}
+
+void MicrosoftCXXNameMangler::mangleType(const AutoType *T, Qualifiers,
+                                         SourceRange Range) {
+  assert(T->getDeducedType().isNull() && "expecting a dependent type!");
+
+  DiagnosticsEngine &Diags = Context.getDiags();
+  unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
+    "cannot mangle this 'auto' type yet");
+  Diags.Report(Range.getBegin(), DiagID)
+    << Range;
+}
+
+void MicrosoftCXXNameMangler::mangleType(
+    const DeducedTemplateSpecializationType *T, Qualifiers, SourceRange Range) {
+  assert(T->getDeducedType().isNull() && "expecting a dependent type!");
+
+  DiagnosticsEngine &Diags = Context.getDiags();
+  unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
+    "cannot mangle this deduced class template specialization type yet");
+  Diags.Report(Range.getBegin(), DiagID)
+    << Range;
+}
+
+void MicrosoftCXXNameMangler::mangleType(const AtomicType *T, Qualifiers,
+                                         SourceRange Range) {
+  QualType ValueType = T->getValueType();
+
+  llvm::SmallString<64> TemplateMangling;
+  llvm::raw_svector_ostream Stream(TemplateMangling);
+  MicrosoftCXXNameMangler Extra(Context, Stream);
+  Stream << "?$";
+  Extra.mangleSourceName("_Atomic");
+  Extra.mangleType(ValueType, Range, QMM_Escape);
+
+  mangleArtificialTagType(TTK_Struct, TemplateMangling, {"__clang"});
+}
+
+void MicrosoftCXXNameMangler::mangleType(const PipeType *T, Qualifiers,
+                                         SourceRange Range) {
+  DiagnosticsEngine &Diags = Context.getDiags();
+  unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
+    "cannot mangle this OpenCL pipe type yet");
+  Diags.Report(Range.getBegin(), DiagID)
+    << Range;
+}
+
+void MicrosoftMangleContextImpl::mangleCXXName(const NamedDecl *D,
+                                               raw_ostream &Out) {
+  assert((isa<FunctionDecl>(D) || isa<VarDecl>(D)) &&
+         "Invalid mangleName() call, argument is not a variable or function!");
+  assert(!isa<CXXConstructorDecl>(D) && !isa<CXXDestructorDecl>(D) &&
+         "Invalid mangleName() call on 'structor decl!");
+
+  PrettyStackTraceDecl CrashInfo(D, SourceLocation(),
+                                 getASTContext().getSourceManager(),
+                                 "Mangling declaration");
+
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler Mangler(*this, MHO);
+  return Mangler.mangle(D);
+}
+
+// <this-adjustment> ::= <no-adjustment> | <static-adjustment> |
+//                       <virtual-adjustment>
+// <no-adjustment>      ::= A # private near
+//                      ::= B # private far
+//                      ::= I # protected near
+//                      ::= J # protected far
+//                      ::= Q # public near
+//                      ::= R # public far
+// <static-adjustment>  ::= G <static-offset> # private near
+//                      ::= H <static-offset> # private far
+//                      ::= O <static-offset> # protected near
+//                      ::= P <static-offset> # protected far
+//                      ::= W <static-offset> # public near
+//                      ::= X <static-offset> # public far
+// <virtual-adjustment> ::= $0 <virtual-shift> <static-offset> # private near
+//                      ::= $1 <virtual-shift> <static-offset> # private far
+//                      ::= $2 <virtual-shift> <static-offset> # protected near
+//                      ::= $3 <virtual-shift> <static-offset> # protected far
+//                      ::= $4 <virtual-shift> <static-offset> # public near
+//                      ::= $5 <virtual-shift> <static-offset> # public far
+// <virtual-shift>      ::= <vtordisp-shift> | <vtordispex-shift>
+// <vtordisp-shift>     ::= <offset-to-vtordisp>
+// <vtordispex-shift>   ::= <offset-to-vbptr> <vbase-offset-offset>
+//                          <offset-to-vtordisp>
+static void mangleThunkThisAdjustment(AccessSpecifier AS,
+                                      const ThisAdjustment &Adjustment,
+                                      MicrosoftCXXNameMangler &Mangler,
+                                      raw_ostream &Out) {
+  if (!Adjustment.Virtual.isEmpty()) {
+    Out << '$';
+    char AccessSpec;
+    switch (AS) {
+    case AS_none:
+      llvm_unreachable("Unsupported access specifier");
+    case AS_private:
+      AccessSpec = '0';
+      break;
+    case AS_protected:
+      AccessSpec = '2';
+      break;
+    case AS_public:
+      AccessSpec = '4';
+    }
+    if (Adjustment.Virtual.Microsoft.VBPtrOffset) {
+      Out << 'R' << AccessSpec;
+      Mangler.mangleNumber(
+          static_cast<uint32_t>(Adjustment.Virtual.Microsoft.VBPtrOffset));
+      Mangler.mangleNumber(
+          static_cast<uint32_t>(Adjustment.Virtual.Microsoft.VBOffsetOffset));
+      Mangler.mangleNumber(
+          static_cast<uint32_t>(Adjustment.Virtual.Microsoft.VtordispOffset));
+      Mangler.mangleNumber(static_cast<uint32_t>(Adjustment.NonVirtual));
+    } else {
+      Out << AccessSpec;
+      Mangler.mangleNumber(
+          static_cast<uint32_t>(Adjustment.Virtual.Microsoft.VtordispOffset));
+      Mangler.mangleNumber(-static_cast<uint32_t>(Adjustment.NonVirtual));
+    }
+  } else if (Adjustment.NonVirtual != 0) {
+    switch (AS) {
+    case AS_none:
+      llvm_unreachable("Unsupported access specifier");
+    case AS_private:
+      Out << 'G';
+      break;
+    case AS_protected:
+      Out << 'O';
+      break;
+    case AS_public:
+      Out << 'W';
+    }
+    Mangler.mangleNumber(-static_cast<uint32_t>(Adjustment.NonVirtual));
+  } else {
+    switch (AS) {
+    case AS_none:
+      llvm_unreachable("Unsupported access specifier");
+    case AS_private:
+      Out << 'A';
+      break;
+    case AS_protected:
+      Out << 'I';
+      break;
+    case AS_public:
+      Out << 'Q';
+    }
+  }
+}
+
+void MicrosoftMangleContextImpl::mangleVirtualMemPtrThunk(
+    const CXXMethodDecl *MD, const MethodVFTableLocation &ML,
+    raw_ostream &Out) {
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler Mangler(*this, MHO);
+  Mangler.getStream() << '?';
+  Mangler.mangleVirtualMemPtrThunk(MD, ML);
+}
+
+void MicrosoftMangleContextImpl::mangleThunk(const CXXMethodDecl *MD,
+                                             const ThunkInfo &Thunk,
+                                             raw_ostream &Out) {
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler Mangler(*this, MHO);
+  Mangler.getStream() << '?';
+  Mangler.mangleName(MD);
+
+  // Usually the thunk uses the access specifier of the new method, but if this
+  // is a covariant return thunk, then MSVC always uses the public access
+  // specifier, and we do the same.
+  AccessSpecifier AS = Thunk.Return.isEmpty() ? MD->getAccess() : AS_public;
+  mangleThunkThisAdjustment(AS, Thunk.This, Mangler, MHO);
+
+  if (!Thunk.Return.isEmpty())
+    assert(Thunk.Method != nullptr &&
+           "Thunk info should hold the overridee decl");
+
+  const CXXMethodDecl *DeclForFPT = Thunk.Method ? Thunk.Method : MD;
+  Mangler.mangleFunctionType(
+      DeclForFPT->getType()->castAs<FunctionProtoType>(), MD);
+}
+
+void MicrosoftMangleContextImpl::mangleCXXDtorThunk(
+    const CXXDestructorDecl *DD, CXXDtorType Type,
+    const ThisAdjustment &Adjustment, raw_ostream &Out) {
+  // FIXME: Actually, the dtor thunk should be emitted for vector deleting
+  // dtors rather than scalar deleting dtors. Just use the vector deleting dtor
+  // mangling manually until we support both deleting dtor types.
+  assert(Type == Dtor_Deleting);
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler Mangler(*this, MHO, DD, Type);
+  Mangler.getStream() << "??_E";
+  Mangler.mangleName(DD->getParent());
+  mangleThunkThisAdjustment(DD->getAccess(), Adjustment, Mangler, MHO);
+  Mangler.mangleFunctionType(DD->getType()->castAs<FunctionProtoType>(), DD);
+}
+
+void MicrosoftMangleContextImpl::mangleCXXVFTable(
+    const CXXRecordDecl *Derived, ArrayRef<const CXXRecordDecl *> BasePath,
+    raw_ostream &Out) {
+  // <mangled-name> ::= ?_7 <class-name> <storage-class>
+  //                    <cvr-qualifiers> [<name>] @
+  // NOTE: <cvr-qualifiers> here is always 'B' (const). <storage-class>
+  // is always '6' for vftables.
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler Mangler(*this, MHO);
+  if (Derived->hasAttr<DLLImportAttr>())
+    Mangler.getStream() << "??_S";
+  else
+    Mangler.getStream() << "??_7";
+  Mangler.mangleName(Derived);
+  Mangler.getStream() << "6B"; // '6' for vftable, 'B' for const.
+  for (const CXXRecordDecl *RD : BasePath)
+    Mangler.mangleName(RD);
+  Mangler.getStream() << '@';
+}
+
+void MicrosoftMangleContextImpl::mangleCXXVBTable(
+    const CXXRecordDecl *Derived, ArrayRef<const CXXRecordDecl *> BasePath,
+    raw_ostream &Out) {
+  // <mangled-name> ::= ?_8 <class-name> <storage-class>
+  //                    <cvr-qualifiers> [<name>] @
+  // NOTE: <cvr-qualifiers> here is always 'B' (const). <storage-class>
+  // is always '7' for vbtables.
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler Mangler(*this, MHO);
+  Mangler.getStream() << "??_8";
+  Mangler.mangleName(Derived);
+  Mangler.getStream() << "7B";  // '7' for vbtable, 'B' for const.
+  for (const CXXRecordDecl *RD : BasePath)
+    Mangler.mangleName(RD);
+  Mangler.getStream() << '@';
+}
+
+void MicrosoftMangleContextImpl::mangleCXXRTTI(QualType T, raw_ostream &Out) {
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler Mangler(*this, MHO);
+  Mangler.getStream() << "??_R0";
+  Mangler.mangleType(T, SourceRange(), MicrosoftCXXNameMangler::QMM_Result);
+  Mangler.getStream() << "@8";
+}
+
+void MicrosoftMangleContextImpl::mangleCXXRTTIName(QualType T,
+                                                   raw_ostream &Out) {
+  MicrosoftCXXNameMangler Mangler(*this, Out);
+  Mangler.getStream() << '.';
+  Mangler.mangleType(T, SourceRange(), MicrosoftCXXNameMangler::QMM_Result);
+}
+
+void MicrosoftMangleContextImpl::mangleCXXVirtualDisplacementMap(
+    const CXXRecordDecl *SrcRD, const CXXRecordDecl *DstRD, raw_ostream &Out) {
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler Mangler(*this, MHO);
+  Mangler.getStream() << "??_K";
+  Mangler.mangleName(SrcRD);
+  Mangler.getStream() << "$C";
+  Mangler.mangleName(DstRD);
+}
+
+void MicrosoftMangleContextImpl::mangleCXXThrowInfo(QualType T, bool IsConst,
+                                                    bool IsVolatile,
+                                                    bool IsUnaligned,
+                                                    uint32_t NumEntries,
+                                                    raw_ostream &Out) {
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler Mangler(*this, MHO);
+  Mangler.getStream() << "_TI";
+  if (IsConst)
+    Mangler.getStream() << 'C';
+  if (IsVolatile)
+    Mangler.getStream() << 'V';
+  if (IsUnaligned)
+    Mangler.getStream() << 'U';
+  Mangler.getStream() << NumEntries;
+  Mangler.mangleType(T, SourceRange(), MicrosoftCXXNameMangler::QMM_Result);
+}
+
+void MicrosoftMangleContextImpl::mangleCXXCatchableTypeArray(
+    QualType T, uint32_t NumEntries, raw_ostream &Out) {
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler Mangler(*this, MHO);
+  Mangler.getStream() << "_CTA";
+  Mangler.getStream() << NumEntries;
+  Mangler.mangleType(T, SourceRange(), MicrosoftCXXNameMangler::QMM_Result);
+}
+
+void MicrosoftMangleContextImpl::mangleCXXCatchableType(
+    QualType T, const CXXConstructorDecl *CD, CXXCtorType CT, uint32_t Size,
+    uint32_t NVOffset, int32_t VBPtrOffset, uint32_t VBIndex,
+    raw_ostream &Out) {
+  MicrosoftCXXNameMangler Mangler(*this, Out);
+  Mangler.getStream() << "_CT";
+
+  llvm::SmallString<64> RTTIMangling;
+  {
+    llvm::raw_svector_ostream Stream(RTTIMangling);
+    msvc_hashing_ostream MHO(Stream);
+    mangleCXXRTTI(T, MHO);
+  }
+  Mangler.getStream() << RTTIMangling;
+
+  // VS2015 and VS2017.1 omit the copy-constructor in the mangled name but
+  // both older and newer versions include it.
+  // FIXME: It is known that the Ctor is present in 2013, and in 2017.7
+  // (_MSC_VER 1914) and newer, and that it's omitted in 2015 and 2017.4
+  // (_MSC_VER 1911), but it's unknown when exactly it reappeared (1914?
+  // Or 1912, 1913 aleady?).
+  bool OmitCopyCtor = getASTContext().getLangOpts().isCompatibleWithMSVC(
+                          LangOptions::MSVC2015) &&
+                      !getASTContext().getLangOpts().isCompatibleWithMSVC(
+                          LangOptions::MSVC2017_7);
+  llvm::SmallString<64> CopyCtorMangling;
+  if (!OmitCopyCtor && CD) {
+    llvm::raw_svector_ostream Stream(CopyCtorMangling);
+    msvc_hashing_ostream MHO(Stream);
+    mangleCXXCtor(CD, CT, MHO);
+  }
+  Mangler.getStream() << CopyCtorMangling;
+
+  Mangler.getStream() << Size;
+  if (VBPtrOffset == -1) {
+    if (NVOffset) {
+      Mangler.getStream() << NVOffset;
+    }
+  } else {
+    Mangler.getStream() << NVOffset;
+    Mangler.getStream() << VBPtrOffset;
+    Mangler.getStream() << VBIndex;
+  }
+}
+
+void MicrosoftMangleContextImpl::mangleCXXRTTIBaseClassDescriptor(
+    const CXXRecordDecl *Derived, uint32_t NVOffset, int32_t VBPtrOffset,
+    uint32_t VBTableOffset, uint32_t Flags, raw_ostream &Out) {
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler Mangler(*this, MHO);
+  Mangler.getStream() << "??_R1";
+  Mangler.mangleNumber(NVOffset);
+  Mangler.mangleNumber(VBPtrOffset);
+  Mangler.mangleNumber(VBTableOffset);
+  Mangler.mangleNumber(Flags);
+  Mangler.mangleName(Derived);
+  Mangler.getStream() << "8";
+}
+
+void MicrosoftMangleContextImpl::mangleCXXRTTIBaseClassArray(
+    const CXXRecordDecl *Derived, raw_ostream &Out) {
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler Mangler(*this, MHO);
+  Mangler.getStream() << "??_R2";
+  Mangler.mangleName(Derived);
+  Mangler.getStream() << "8";
+}
+
+void MicrosoftMangleContextImpl::mangleCXXRTTIClassHierarchyDescriptor(
+    const CXXRecordDecl *Derived, raw_ostream &Out) {
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler Mangler(*this, MHO);
+  Mangler.getStream() << "??_R3";
+  Mangler.mangleName(Derived);
+  Mangler.getStream() << "8";
+}
+
+void MicrosoftMangleContextImpl::mangleCXXRTTICompleteObjectLocator(
+    const CXXRecordDecl *Derived, ArrayRef<const CXXRecordDecl *> BasePath,
+    raw_ostream &Out) {
+  // <mangled-name> ::= ?_R4 <class-name> <storage-class>
+  //                    <cvr-qualifiers> [<name>] @
+  // NOTE: <cvr-qualifiers> here is always 'B' (const). <storage-class>
+  // is always '6' for vftables.
+  llvm::SmallString<64> VFTableMangling;
+  llvm::raw_svector_ostream Stream(VFTableMangling);
+  mangleCXXVFTable(Derived, BasePath, Stream);
+
+  if (VFTableMangling.startswith("??@")) {
+    assert(VFTableMangling.endswith("@"));
+    Out << VFTableMangling << "??_R4@";
+    return;
+  }
+
+  assert(VFTableMangling.startswith("??_7") ||
+         VFTableMangling.startswith("??_S"));
+
+  Out << "??_R4" << StringRef(VFTableMangling).drop_front(4);
+}
+
+void MicrosoftMangleContextImpl::mangleSEHFilterExpression(
+    const NamedDecl *EnclosingDecl, raw_ostream &Out) {
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler Mangler(*this, MHO);
+  // The function body is in the same comdat as the function with the handler,
+  // so the numbering here doesn't have to be the same across TUs.
+  //
+  // <mangled-name> ::= ?filt$ <filter-number> @0
+  Mangler.getStream() << "?filt$" << SEHFilterIds[EnclosingDecl]++ << "@0@";
+  Mangler.mangleName(EnclosingDecl);
+}
+
+void MicrosoftMangleContextImpl::mangleSEHFinallyBlock(
+    const NamedDecl *EnclosingDecl, raw_ostream &Out) {
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler Mangler(*this, MHO);
+  // The function body is in the same comdat as the function with the handler,
+  // so the numbering here doesn't have to be the same across TUs.
+  //
+  // <mangled-name> ::= ?fin$ <filter-number> @0
+  Mangler.getStream() << "?fin$" << SEHFinallyIds[EnclosingDecl]++ << "@0@";
+  Mangler.mangleName(EnclosingDecl);
+}
+
+void MicrosoftMangleContextImpl::mangleTypeName(QualType T, raw_ostream &Out) {
+  // This is just a made up unique string for the purposes of tbaa.  undname
+  // does *not* know how to demangle it.
+  MicrosoftCXXNameMangler Mangler(*this, Out);
+  Mangler.getStream() << '?';
+  Mangler.mangleType(T, SourceRange());
+}
+
+void MicrosoftMangleContextImpl::mangleCXXCtor(const CXXConstructorDecl *D,
+                                               CXXCtorType Type,
+                                               raw_ostream &Out) {
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler mangler(*this, MHO, D, Type);
+  mangler.mangle(D);
+}
+
+void MicrosoftMangleContextImpl::mangleCXXDtor(const CXXDestructorDecl *D,
+                                               CXXDtorType Type,
+                                               raw_ostream &Out) {
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler mangler(*this, MHO, D, Type);
+  mangler.mangle(D);
+}
+
+void MicrosoftMangleContextImpl::mangleReferenceTemporary(
+    const VarDecl *VD, unsigned ManglingNumber, raw_ostream &Out) {
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler Mangler(*this, MHO);
+
+  Mangler.getStream() << "?$RT" << ManglingNumber << '@';
+  Mangler.mangle(VD, "");
+}
+
+void MicrosoftMangleContextImpl::mangleThreadSafeStaticGuardVariable(
+    const VarDecl *VD, unsigned GuardNum, raw_ostream &Out) {
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler Mangler(*this, MHO);
+
+  Mangler.getStream() << "?$TSS" << GuardNum << '@';
+  Mangler.mangleNestedName(VD);
+  Mangler.getStream() << "@4HA";
+}
+
+void MicrosoftMangleContextImpl::mangleStaticGuardVariable(const VarDecl *VD,
+                                                           raw_ostream &Out) {
+  // <guard-name> ::= ?_B <postfix> @5 <scope-depth>
+  //              ::= ?__J <postfix> @5 <scope-depth>
+  //              ::= ?$S <guard-num> @ <postfix> @4IA
+
+  // The first mangling is what MSVC uses to guard static locals in inline
+  // functions.  It uses a different mangling in external functions to support
+  // guarding more than 32 variables.  MSVC rejects inline functions with more
+  // than 32 static locals.  We don't fully implement the second mangling
+  // because those guards are not externally visible, and instead use LLVM's
+  // default renaming when creating a new guard variable.
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler Mangler(*this, MHO);
+
+  bool Visible = VD->isExternallyVisible();
+  if (Visible) {
+    Mangler.getStream() << (VD->getTLSKind() ? "??__J" : "??_B");
+  } else {
+    Mangler.getStream() << "?$S1@";
+  }
+  unsigned ScopeDepth = 0;
+  if (Visible && !getNextDiscriminator(VD, ScopeDepth))
+    // If we do not have a discriminator and are emitting a guard variable for
+    // use at global scope, then mangling the nested name will not be enough to
+    // remove ambiguities.
+    Mangler.mangle(VD, "");
+  else
+    Mangler.mangleNestedName(VD);
+  Mangler.getStream() << (Visible ? "@5" : "@4IA");
+  if (ScopeDepth)
+    Mangler.mangleNumber(ScopeDepth);
+}
+
+void MicrosoftMangleContextImpl::mangleInitFiniStub(const VarDecl *D,
+                                                    char CharCode,
+                                                    raw_ostream &Out) {
+  msvc_hashing_ostream MHO(Out);
+  MicrosoftCXXNameMangler Mangler(*this, MHO);
+  Mangler.getStream() << "??__" << CharCode;
+  if (D->isStaticDataMember()) {
+    Mangler.getStream() << '?';
+    Mangler.mangleName(D);
+    Mangler.mangleVariableEncoding(D);
+    Mangler.getStream() << "@@";
+  } else {
+    Mangler.mangleName(D);
+  }
+  // This is the function class mangling.  These stubs are global, non-variadic,
+  // cdecl functions that return void and take no args.
+  Mangler.getStream() << "YAXXZ";
+}
+
+void MicrosoftMangleContextImpl::mangleDynamicInitializer(const VarDecl *D,
+                                                          raw_ostream &Out) {
+  // <initializer-name> ::= ?__E <name> YAXXZ
+  mangleInitFiniStub(D, 'E', Out);
+}
+
+void
+MicrosoftMangleContextImpl::mangleDynamicAtExitDestructor(const VarDecl *D,
+                                                          raw_ostream &Out) {
+  // <destructor-name> ::= ?__F <name> YAXXZ
+  mangleInitFiniStub(D, 'F', Out);
+}
+
+void MicrosoftMangleContextImpl::mangleStringLiteral(const StringLiteral *SL,
+                                                     raw_ostream &Out) {
+  // <char-type> ::= 0   # char, char16_t, char32_t
+  //                     # (little endian char data in mangling)
+  //             ::= 1   # wchar_t (big endian char data in mangling)
+  //
+  // <literal-length> ::= <non-negative integer>  # the length of the literal
+  //
+  // <encoded-crc>    ::= <hex digit>+ @          # crc of the literal including
+  //                                              # trailing null bytes
+  //
+  // <encoded-string> ::= <simple character>           # uninteresting character
+  //                  ::= '?$' <hex digit> <hex digit> # these two nibbles
+  //                                                   # encode the byte for the
+  //                                                   # character
+  //                  ::= '?' [a-z]                    # \xe1 - \xfa
+  //                  ::= '?' [A-Z]                    # \xc1 - \xda
+  //                  ::= '?' [0-9]                    # [,/\:. \n\t'-]
+  //
+  // <literal> ::= '??_C@_' <char-type> <literal-length> <encoded-crc>
+  //               <encoded-string> '@'
+  MicrosoftCXXNameMangler Mangler(*this, Out);
+  Mangler.getStream() << "??_C@_";
+
+  // The actual string length might be different from that of the string literal
+  // in cases like:
+  // char foo[3] = "foobar";
+  // char bar[42] = "foobar";
+  // Where it is truncated or zero-padded to fit the array. This is the length
+  // used for mangling, and any trailing null-bytes also need to be mangled.
+  unsigned StringLength = getASTContext()
+                              .getAsConstantArrayType(SL->getType())
+                              ->getSize()
+                              .getZExtValue();
+  unsigned StringByteLength = StringLength * SL->getCharByteWidth();
+
+  // <char-type>: The "kind" of string literal is encoded into the mangled name.
+  if (SL->isWide())
+    Mangler.getStream() << '1';
+  else
+    Mangler.getStream() << '0';
+
+  // <literal-length>: The next part of the mangled name consists of the length
+  // of the string in bytes.
+  Mangler.mangleNumber(StringByteLength);
+
+  auto GetLittleEndianByte = [&SL](unsigned Index) {
+    unsigned CharByteWidth = SL->getCharByteWidth();
+    if (Index / CharByteWidth >= SL->getLength())
+      return static_cast<char>(0);
+    uint32_t CodeUnit = SL->getCodeUnit(Index / CharByteWidth);
+    unsigned OffsetInCodeUnit = Index % CharByteWidth;
+    return static_cast<char>((CodeUnit >> (8 * OffsetInCodeUnit)) & 0xff);
+  };
+
+  auto GetBigEndianByte = [&SL](unsigned Index) {
+    unsigned CharByteWidth = SL->getCharByteWidth();
+    if (Index / CharByteWidth >= SL->getLength())
+      return static_cast<char>(0);
+    uint32_t CodeUnit = SL->getCodeUnit(Index / CharByteWidth);
+    unsigned OffsetInCodeUnit = (CharByteWidth - 1) - (Index % CharByteWidth);
+    return static_cast<char>((CodeUnit >> (8 * OffsetInCodeUnit)) & 0xff);
+  };
+
+  // CRC all the bytes of the StringLiteral.
+  llvm::JamCRC JC;
+  for (unsigned I = 0, E = StringByteLength; I != E; ++I)
+    JC.update(GetLittleEndianByte(I));
+
+  // <encoded-crc>: The CRC is encoded utilizing the standard number mangling
+  // scheme.
+  Mangler.mangleNumber(JC.getCRC());
+
+  // <encoded-string>: The mangled name also contains the first 32 bytes
+  // (including null-terminator bytes) of the encoded StringLiteral.
+  // Each character is encoded by splitting them into bytes and then encoding
+  // the constituent bytes.
+  auto MangleByte = [&Mangler](char Byte) {
+    // There are five different manglings for characters:
+    // - [a-zA-Z0-9_$]: A one-to-one mapping.
+    // - ?[a-z]: The range from \xe1 to \xfa.
+    // - ?[A-Z]: The range from \xc1 to \xda.
+    // - ?[0-9]: The set of [,/\:. \n\t'-].
+    // - ?$XX: A fallback which maps nibbles.
+    if (isIdentifierBody(Byte, /*AllowDollar=*/true)) {
+      Mangler.getStream() << Byte;
+    } else if (isLetter(Byte & 0x7f)) {
+      Mangler.getStream() << '?' << static_cast<char>(Byte & 0x7f);
+    } else {
+      const char SpecialChars[] = {',', '/',  '\\', ':',  '.',
+                                   ' ', '\n', '\t', '\'', '-'};
+      const char *Pos = llvm::find(SpecialChars, Byte);
+      if (Pos != std::end(SpecialChars)) {
+        Mangler.getStream() << '?' << (Pos - std::begin(SpecialChars));
+      } else {
+        Mangler.getStream() << "?$";
+        Mangler.getStream() << static_cast<char>('A' + ((Byte >> 4) & 0xf));
+        Mangler.getStream() << static_cast<char>('A' + (Byte & 0xf));
+      }
+    }
+  };
+
+  // Enforce our 32 bytes max, except wchar_t which gets 32 chars instead.
+  unsigned MaxBytesToMangle = SL->isWide() ? 64U : 32U;
+  unsigned NumBytesToMangle = std::min(MaxBytesToMangle, StringByteLength);
+  for (unsigned I = 0; I != NumBytesToMangle; ++I) {
+    if (SL->isWide())
+      MangleByte(GetBigEndianByte(I));
+    else
+      MangleByte(GetLittleEndianByte(I));
+  }
+
+  Mangler.getStream() << '@';
+}
+
+MicrosoftMangleContext *
+MicrosoftMangleContext::create(ASTContext &Context, DiagnosticsEngine &Diags) {
+  return new MicrosoftMangleContextImpl(Context, Diags);
+}