1 //===--- MicrosoftMangle.cpp - Microsoft Visual C++ Name Mangling ---------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This provides C++ name mangling targeting the Microsoft Visual C++ ABI.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "clang/AST/Mangle.h"
14 #include "clang/AST/ASTContext.h"
15 #include "clang/AST/Attr.h"
16 #include "clang/AST/CXXInheritance.h"
17 #include "clang/AST/CharUnits.h"
18 #include "clang/AST/Decl.h"
19 #include "clang/AST/DeclCXX.h"
20 #include "clang/AST/DeclObjC.h"
21 #include "clang/AST/DeclOpenMP.h"
22 #include "clang/AST/DeclTemplate.h"
23 #include "clang/AST/Expr.h"
24 #include "clang/AST/ExprCXX.h"
25 #include "clang/AST/VTableBuilder.h"
26 #include "clang/Basic/ABI.h"
27 #include "clang/Basic/DiagnosticOptions.h"
28 #include "clang/Basic/TargetInfo.h"
29 #include "llvm/ADT/StringExtras.h"
30 #include "llvm/Support/JamCRC.h"
31 #include "llvm/Support/xxhash.h"
32 #include "llvm/Support/MD5.h"
33 #include "llvm/Support/MathExtras.h"
34 #include "llvm/Support/StringSaver.h"
35 
36 using namespace clang;
37 
38 namespace {
39 
40 struct msvc_hashing_ostream : public llvm::raw_svector_ostream {
41   raw_ostream &OS;
42   llvm::SmallString<64> Buffer;
43 
44   msvc_hashing_ostream(raw_ostream &OS)
45       : llvm::raw_svector_ostream(Buffer), OS(OS) {}
46   ~msvc_hashing_ostream() override {
47     StringRef MangledName = str();
48     bool StartsWithEscape = MangledName.startswith("\01");
49     if (StartsWithEscape)
50       MangledName = MangledName.drop_front(1);
51     if (MangledName.size() <= 4096) {
52       OS << str();
53       return;
54     }
55 
56     llvm::MD5 Hasher;
57     llvm::MD5::MD5Result Hash;
58     Hasher.update(MangledName);
59     Hasher.final(Hash);
60 
61     SmallString<32> HexString;
62     llvm::MD5::stringifyResult(Hash, HexString);
63 
64     if (StartsWithEscape)
65       OS << '\01';
66     OS << "??@" << HexString << '@';
67   }
68 };
69 
70 static const DeclContext *
71 getLambdaDefaultArgumentDeclContext(const Decl *D) {
72   if (const auto *RD = dyn_cast<CXXRecordDecl>(D))
73     if (RD->isLambda())
74       if (const auto *Parm =
75               dyn_cast_or_null<ParmVarDecl>(RD->getLambdaContextDecl()))
76         return Parm->getDeclContext();
77   return nullptr;
78 }
79 
80 /// Retrieve the declaration context that should be used when mangling
81 /// the given declaration.
82 static const DeclContext *getEffectiveDeclContext(const Decl *D) {
83   // The ABI assumes that lambda closure types that occur within
84   // default arguments live in the context of the function. However, due to
85   // the way in which Clang parses and creates function declarations, this is
86   // not the case: the lambda closure type ends up living in the context
87   // where the function itself resides, because the function declaration itself
88   // had not yet been created. Fix the context here.
89   if (const auto *LDADC = getLambdaDefaultArgumentDeclContext(D))
90     return LDADC;
91 
92   // Perform the same check for block literals.
93   if (const BlockDecl *BD = dyn_cast<BlockDecl>(D)) {
94     if (ParmVarDecl *ContextParam =
95             dyn_cast_or_null<ParmVarDecl>(BD->getBlockManglingContextDecl()))
96       return ContextParam->getDeclContext();
97   }
98 
99   const DeclContext *DC = D->getDeclContext();
100   if (isa<CapturedDecl>(DC) || isa<OMPDeclareReductionDecl>(DC) ||
101       isa<OMPDeclareMapperDecl>(DC)) {
102     return getEffectiveDeclContext(cast<Decl>(DC));
103   }
104 
105   return DC->getRedeclContext();
106 }
107 
108 static const DeclContext *getEffectiveParentContext(const DeclContext *DC) {
109   return getEffectiveDeclContext(cast<Decl>(DC));
110 }
111 
112 static const FunctionDecl *getStructor(const NamedDecl *ND) {
113   if (const auto *FTD = dyn_cast<FunctionTemplateDecl>(ND))
114     return FTD->getTemplatedDecl()->getCanonicalDecl();
115 
116   const auto *FD = cast<FunctionDecl>(ND);
117   if (const auto *FTD = FD->getPrimaryTemplate())
118     return FTD->getTemplatedDecl()->getCanonicalDecl();
119 
120   return FD->getCanonicalDecl();
121 }
122 
123 /// MicrosoftMangleContextImpl - Overrides the default MangleContext for the
124 /// Microsoft Visual C++ ABI.
125 class MicrosoftMangleContextImpl : public MicrosoftMangleContext {
126   typedef std::pair<const DeclContext *, IdentifierInfo *> DiscriminatorKeyTy;
127   llvm::DenseMap<DiscriminatorKeyTy, unsigned> Discriminator;
128   llvm::DenseMap<const NamedDecl *, unsigned> Uniquifier;
129   llvm::DenseMap<const CXXRecordDecl *, unsigned> LambdaIds;
130   llvm::DenseMap<const NamedDecl *, unsigned> SEHFilterIds;
131   llvm::DenseMap<const NamedDecl *, unsigned> SEHFinallyIds;
132   SmallString<16> AnonymousNamespaceHash;
133 
134 public:
135   MicrosoftMangleContextImpl(ASTContext &Context, DiagnosticsEngine &Diags);
136   bool shouldMangleCXXName(const NamedDecl *D) override;
137   bool shouldMangleStringLiteral(const StringLiteral *SL) override;
138   void mangleCXXName(const NamedDecl *D, raw_ostream &Out) override;
139   void mangleVirtualMemPtrThunk(const CXXMethodDecl *MD,
140                                 const MethodVFTableLocation &ML,
141                                 raw_ostream &Out) override;
142   void mangleThunk(const CXXMethodDecl *MD, const ThunkInfo &Thunk,
143                    raw_ostream &) override;
144   void mangleCXXDtorThunk(const CXXDestructorDecl *DD, CXXDtorType Type,
145                           const ThisAdjustment &ThisAdjustment,
146                           raw_ostream &) override;
147   void mangleCXXVFTable(const CXXRecordDecl *Derived,
148                         ArrayRef<const CXXRecordDecl *> BasePath,
149                         raw_ostream &Out) override;
150   void mangleCXXVBTable(const CXXRecordDecl *Derived,
151                         ArrayRef<const CXXRecordDecl *> BasePath,
152                         raw_ostream &Out) override;
153   void mangleCXXVirtualDisplacementMap(const CXXRecordDecl *SrcRD,
154                                        const CXXRecordDecl *DstRD,
155                                        raw_ostream &Out) override;
156   void mangleCXXThrowInfo(QualType T, bool IsConst, bool IsVolatile,
157                           bool IsUnaligned, uint32_t NumEntries,
158                           raw_ostream &Out) override;
159   void mangleCXXCatchableTypeArray(QualType T, uint32_t NumEntries,
160                                    raw_ostream &Out) override;
161   void mangleCXXCatchableType(QualType T, const CXXConstructorDecl *CD,
162                               CXXCtorType CT, uint32_t Size, uint32_t NVOffset,
163                               int32_t VBPtrOffset, uint32_t VBIndex,
164                               raw_ostream &Out) override;
165   void mangleCXXRTTI(QualType T, raw_ostream &Out) override;
166   void mangleCXXRTTIName(QualType T, raw_ostream &Out) override;
167   void mangleCXXRTTIBaseClassDescriptor(const CXXRecordDecl *Derived,
168                                         uint32_t NVOffset, int32_t VBPtrOffset,
169                                         uint32_t VBTableOffset, uint32_t Flags,
170                                         raw_ostream &Out) override;
171   void mangleCXXRTTIBaseClassArray(const CXXRecordDecl *Derived,
172                                    raw_ostream &Out) override;
173   void mangleCXXRTTIClassHierarchyDescriptor(const CXXRecordDecl *Derived,
174                                              raw_ostream &Out) override;
175   void
176   mangleCXXRTTICompleteObjectLocator(const CXXRecordDecl *Derived,
177                                      ArrayRef<const CXXRecordDecl *> BasePath,
178                                      raw_ostream &Out) override;
179   void mangleTypeName(QualType T, raw_ostream &) override;
180   void mangleCXXCtor(const CXXConstructorDecl *D, CXXCtorType Type,
181                      raw_ostream &) override;
182   void mangleCXXDtor(const CXXDestructorDecl *D, CXXDtorType Type,
183                      raw_ostream &) override;
184   void mangleReferenceTemporary(const VarDecl *, unsigned ManglingNumber,
185                                 raw_ostream &) override;
186   void mangleStaticGuardVariable(const VarDecl *D, raw_ostream &Out) override;
187   void mangleThreadSafeStaticGuardVariable(const VarDecl *D, unsigned GuardNum,
188                                            raw_ostream &Out) override;
189   void mangleDynamicInitializer(const VarDecl *D, raw_ostream &Out) override;
190   void mangleDynamicAtExitDestructor(const VarDecl *D,
191                                      raw_ostream &Out) override;
192   void mangleSEHFilterExpression(const NamedDecl *EnclosingDecl,
193                                  raw_ostream &Out) override;
194   void mangleSEHFinallyBlock(const NamedDecl *EnclosingDecl,
195                              raw_ostream &Out) override;
196   void mangleStringLiteral(const StringLiteral *SL, raw_ostream &Out) override;
197   bool getNextDiscriminator(const NamedDecl *ND, unsigned &disc) {
198     const DeclContext *DC = getEffectiveDeclContext(ND);
199     if (!DC->isFunctionOrMethod())
200       return false;
201 
202     // Lambda closure types are already numbered, give out a phony number so
203     // that they demangle nicely.
204     if (const auto *RD = dyn_cast<CXXRecordDecl>(ND)) {
205       if (RD->isLambda()) {
206         disc = 1;
207         return true;
208       }
209     }
210 
211     // Use the canonical number for externally visible decls.
212     if (ND->isExternallyVisible()) {
213       disc = getASTContext().getManglingNumber(ND);
214       return true;
215     }
216 
217     // Anonymous tags are already numbered.
218     if (const TagDecl *Tag = dyn_cast<TagDecl>(ND)) {
219       if (!Tag->hasNameForLinkage() &&
220           !getASTContext().getDeclaratorForUnnamedTagDecl(Tag) &&
221           !getASTContext().getTypedefNameForUnnamedTagDecl(Tag))
222         return false;
223     }
224 
225     // Make up a reasonable number for internal decls.
226     unsigned &discriminator = Uniquifier[ND];
227     if (!discriminator)
228       discriminator = ++Discriminator[std::make_pair(DC, ND->getIdentifier())];
229     disc = discriminator + 1;
230     return true;
231   }
232 
233   unsigned getLambdaId(const CXXRecordDecl *RD) {
234     assert(RD->isLambda() && "RD must be a lambda!");
235     assert(!RD->isExternallyVisible() && "RD must not be visible!");
236     assert(RD->getLambdaManglingNumber() == 0 &&
237            "RD must not have a mangling number!");
238     std::pair<llvm::DenseMap<const CXXRecordDecl *, unsigned>::iterator, bool>
239         Result = LambdaIds.insert(std::make_pair(RD, LambdaIds.size()));
240     return Result.first->second;
241   }
242 
243   /// Return a character sequence that is (somewhat) unique to the TU suitable
244   /// for mangling anonymous namespaces.
245   StringRef getAnonymousNamespaceHash() const {
246     return AnonymousNamespaceHash;
247   }
248 
249 private:
250   void mangleInitFiniStub(const VarDecl *D, char CharCode, raw_ostream &Out);
251 };
252 
253 /// MicrosoftCXXNameMangler - Manage the mangling of a single name for the
254 /// Microsoft Visual C++ ABI.
255 class MicrosoftCXXNameMangler {
256   MicrosoftMangleContextImpl &Context;
257   raw_ostream &Out;
258 
259   /// The "structor" is the top-level declaration being mangled, if
260   /// that's not a template specialization; otherwise it's the pattern
261   /// for that specialization.
262   const NamedDecl *Structor;
263   unsigned StructorType;
264 
265   typedef llvm::SmallVector<std::string, 10> BackRefVec;
266   BackRefVec NameBackReferences;
267 
268   typedef llvm::DenseMap<const void *, unsigned> ArgBackRefMap;
269   ArgBackRefMap FunArgBackReferences;
270   ArgBackRefMap TemplateArgBackReferences;
271 
272   typedef llvm::DenseMap<const void *, StringRef> TemplateArgStringMap;
273   TemplateArgStringMap TemplateArgStrings;
274   llvm::StringSaver TemplateArgStringStorage;
275   llvm::BumpPtrAllocator TemplateArgStringStorageAlloc;
276 
277   typedef std::set<std::pair<int, bool>> PassObjectSizeArgsSet;
278   PassObjectSizeArgsSet PassObjectSizeArgs;
279 
280   ASTContext &getASTContext() const { return Context.getASTContext(); }
281 
282   // FIXME: If we add support for __ptr32/64 qualifiers, then we should push
283   // this check into mangleQualifiers().
284   const bool PointersAre64Bit;
285 
286 public:
287   enum QualifierMangleMode { QMM_Drop, QMM_Mangle, QMM_Escape, QMM_Result };
288 
289   MicrosoftCXXNameMangler(MicrosoftMangleContextImpl &C, raw_ostream &Out_)
290       : Context(C), Out(Out_), Structor(nullptr), StructorType(-1),
291         TemplateArgStringStorage(TemplateArgStringStorageAlloc),
292         PointersAre64Bit(C.getASTContext().getTargetInfo().getPointerWidth(0) ==
293                          64) {}
294 
295   MicrosoftCXXNameMangler(MicrosoftMangleContextImpl &C, raw_ostream &Out_,
296                           const CXXConstructorDecl *D, CXXCtorType Type)
297       : Context(C), Out(Out_), Structor(getStructor(D)), StructorType(Type),
298         TemplateArgStringStorage(TemplateArgStringStorageAlloc),
299         PointersAre64Bit(C.getASTContext().getTargetInfo().getPointerWidth(0) ==
300                          64) {}
301 
302   MicrosoftCXXNameMangler(MicrosoftMangleContextImpl &C, raw_ostream &Out_,
303                           const CXXDestructorDecl *D, CXXDtorType Type)
304       : Context(C), Out(Out_), Structor(getStructor(D)), StructorType(Type),
305         TemplateArgStringStorage(TemplateArgStringStorageAlloc),
306         PointersAre64Bit(C.getASTContext().getTargetInfo().getPointerWidth(0) ==
307                          64) {}
308 
309   raw_ostream &getStream() const { return Out; }
310 
311   void mangle(const NamedDecl *D, StringRef Prefix = "?");
312   void mangleName(const NamedDecl *ND);
313   void mangleFunctionEncoding(const FunctionDecl *FD, bool ShouldMangle);
314   void mangleVariableEncoding(const VarDecl *VD);
315   void mangleMemberDataPointer(const CXXRecordDecl *RD, const ValueDecl *VD);
316   void mangleMemberFunctionPointer(const CXXRecordDecl *RD,
317                                    const CXXMethodDecl *MD);
318   void mangleVirtualMemPtrThunk(const CXXMethodDecl *MD,
319                                 const MethodVFTableLocation &ML);
320   void mangleNumber(int64_t Number);
321   void mangleTagTypeKind(TagTypeKind TK);
322   void mangleArtificialTagType(TagTypeKind TK, StringRef UnqualifiedName,
323                               ArrayRef<StringRef> NestedNames = None);
324   void mangleAddressSpaceType(QualType T, Qualifiers Quals, SourceRange Range);
325   void mangleType(QualType T, SourceRange Range,
326                   QualifierMangleMode QMM = QMM_Mangle);
327   void mangleFunctionType(const FunctionType *T,
328                           const FunctionDecl *D = nullptr,
329                           bool ForceThisQuals = false,
330                           bool MangleExceptionSpec = true);
331   void mangleNestedName(const NamedDecl *ND);
332 
333 private:
334   bool isStructorDecl(const NamedDecl *ND) const {
335     return ND == Structor || getStructor(ND) == Structor;
336   }
337 
338   void mangleUnqualifiedName(const NamedDecl *ND) {
339     mangleUnqualifiedName(ND, ND->getDeclName());
340   }
341   void mangleUnqualifiedName(const NamedDecl *ND, DeclarationName Name);
342   void mangleSourceName(StringRef Name);
343   void mangleOperatorName(OverloadedOperatorKind OO, SourceLocation Loc);
344   void mangleCXXDtorType(CXXDtorType T);
345   void mangleQualifiers(Qualifiers Quals, bool IsMember);
346   void mangleRefQualifier(RefQualifierKind RefQualifier);
347   void manglePointerCVQualifiers(Qualifiers Quals);
348   void manglePointerExtQualifiers(Qualifiers Quals, QualType PointeeType);
349 
350   void mangleUnscopedTemplateName(const TemplateDecl *ND);
351   void
352   mangleTemplateInstantiationName(const TemplateDecl *TD,
353                                   const TemplateArgumentList &TemplateArgs);
354   void mangleObjCMethodName(const ObjCMethodDecl *MD);
355 
356   void mangleFunctionArgumentType(QualType T, SourceRange Range);
357   void manglePassObjectSizeArg(const PassObjectSizeAttr *POSA);
358 
359   bool isArtificialTagType(QualType T) const;
360 
361   // Declare manglers for every type class.
362 #define ABSTRACT_TYPE(CLASS, PARENT)
363 #define NON_CANONICAL_TYPE(CLASS, PARENT)
364 #define TYPE(CLASS, PARENT) void mangleType(const CLASS##Type *T, \
365                                             Qualifiers Quals, \
366                                             SourceRange Range);
367 #include "clang/AST/TypeNodes.def"
368 #undef ABSTRACT_TYPE
369 #undef NON_CANONICAL_TYPE
370 #undef TYPE
371 
372   void mangleType(const TagDecl *TD);
373   void mangleDecayedArrayType(const ArrayType *T);
374   void mangleArrayType(const ArrayType *T);
375   void mangleFunctionClass(const FunctionDecl *FD);
376   void mangleCallingConvention(CallingConv CC);
377   void mangleCallingConvention(const FunctionType *T);
378   void mangleIntegerLiteral(const llvm::APSInt &Number, bool IsBoolean);
379   void mangleExpression(const Expr *E);
380   void mangleThrowSpecification(const FunctionProtoType *T);
381 
382   void mangleTemplateArgs(const TemplateDecl *TD,
383                           const TemplateArgumentList &TemplateArgs);
384   void mangleTemplateArg(const TemplateDecl *TD, const TemplateArgument &TA,
385                          const NamedDecl *Parm);
386 
387   void mangleObjCProtocol(const ObjCProtocolDecl *PD);
388   void mangleObjCLifetime(const QualType T, Qualifiers Quals,
389                           SourceRange Range);
390   void mangleObjCKindOfType(const ObjCObjectType *T, Qualifiers Quals,
391                             SourceRange Range);
392 };
393 }
394 
395 MicrosoftMangleContextImpl::MicrosoftMangleContextImpl(ASTContext &Context,
396                                                        DiagnosticsEngine &Diags)
397     : MicrosoftMangleContext(Context, Diags) {
398   // To mangle anonymous namespaces, hash the path to the main source file. The
399   // path should be whatever (probably relative) path was passed on the command
400   // line. The goal is for the compiler to produce the same output regardless of
401   // working directory, so use the uncanonicalized relative path.
402   //
403   // It's important to make the mangled names unique because, when CodeView
404   // debug info is in use, the debugger uses mangled type names to distinguish
405   // between otherwise identically named types in anonymous namespaces.
406   //
407   // These symbols are always internal, so there is no need for the hash to
408   // match what MSVC produces. For the same reason, clang is free to change the
409   // hash at any time without breaking compatibility with old versions of clang.
410   // The generated names are intended to look similar to what MSVC generates,
411   // which are something like "?A0x01234567@".
412   SourceManager &SM = Context.getSourceManager();
413   if (const FileEntry *FE = SM.getFileEntryForID(SM.getMainFileID())) {
414     // Truncate the hash so we get 8 characters of hexadecimal.
415     uint32_t TruncatedHash = uint32_t(xxHash64(FE->getName()));
416     AnonymousNamespaceHash = llvm::utohexstr(TruncatedHash);
417   } else {
418     // If we don't have a path to the main file, we'll just use 0.
419     AnonymousNamespaceHash = "0";
420   }
421 }
422 
423 bool MicrosoftMangleContextImpl::shouldMangleCXXName(const NamedDecl *D) {
424   if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
425     LanguageLinkage L = FD->getLanguageLinkage();
426     // Overloadable functions need mangling.
427     if (FD->hasAttr<OverloadableAttr>())
428       return true;
429 
430     // The ABI expects that we would never mangle "typical" user-defined entry
431     // points regardless of visibility or freestanding-ness.
432     //
433     // N.B. This is distinct from asking about "main".  "main" has a lot of
434     // special rules associated with it in the standard while these
435     // user-defined entry points are outside of the purview of the standard.
436     // For example, there can be only one definition for "main" in a standards
437     // compliant program; however nothing forbids the existence of wmain and
438     // WinMain in the same translation unit.
439     if (FD->isMSVCRTEntryPoint())
440       return false;
441 
442     // C++ functions and those whose names are not a simple identifier need
443     // mangling.
444     if (!FD->getDeclName().isIdentifier() || L == CXXLanguageLinkage)
445       return true;
446 
447     // C functions are not mangled.
448     if (L == CLanguageLinkage)
449       return false;
450   }
451 
452   // Otherwise, no mangling is done outside C++ mode.
453   if (!getASTContext().getLangOpts().CPlusPlus)
454     return false;
455 
456   const VarDecl *VD = dyn_cast<VarDecl>(D);
457   if (VD && !isa<DecompositionDecl>(D)) {
458     // C variables are not mangled.
459     if (VD->isExternC())
460       return false;
461 
462     // Variables at global scope with non-internal linkage are not mangled.
463     const DeclContext *DC = getEffectiveDeclContext(D);
464     // Check for extern variable declared locally.
465     if (DC->isFunctionOrMethod() && D->hasLinkage())
466       while (!DC->isNamespace() && !DC->isTranslationUnit())
467         DC = getEffectiveParentContext(DC);
468 
469     if (DC->isTranslationUnit() && D->getFormalLinkage() == InternalLinkage &&
470         !isa<VarTemplateSpecializationDecl>(D) &&
471         D->getIdentifier() != nullptr)
472       return false;
473   }
474 
475   return true;
476 }
477 
478 bool
479 MicrosoftMangleContextImpl::shouldMangleStringLiteral(const StringLiteral *SL) {
480   return true;
481 }
482 
483 void MicrosoftCXXNameMangler::mangle(const NamedDecl *D, StringRef Prefix) {
484   // MSVC doesn't mangle C++ names the same way it mangles extern "C" names.
485   // Therefore it's really important that we don't decorate the
486   // name with leading underscores or leading/trailing at signs. So, by
487   // default, we emit an asm marker at the start so we get the name right.
488   // Callers can override this with a custom prefix.
489 
490   // <mangled-name> ::= ? <name> <type-encoding>
491   Out << Prefix;
492   mangleName(D);
493   if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
494     mangleFunctionEncoding(FD, Context.shouldMangleDeclName(FD));
495   else if (const VarDecl *VD = dyn_cast<VarDecl>(D))
496     mangleVariableEncoding(VD);
497   else
498     llvm_unreachable("Tried to mangle unexpected NamedDecl!");
499 }
500 
501 void MicrosoftCXXNameMangler::mangleFunctionEncoding(const FunctionDecl *FD,
502                                                      bool ShouldMangle) {
503   // <type-encoding> ::= <function-class> <function-type>
504 
505   // Since MSVC operates on the type as written and not the canonical type, it
506   // actually matters which decl we have here.  MSVC appears to choose the
507   // first, since it is most likely to be the declaration in a header file.
508   FD = FD->getFirstDecl();
509 
510   // We should never ever see a FunctionNoProtoType at this point.
511   // We don't even know how to mangle their types anyway :).
512   const FunctionProtoType *FT = FD->getType()->castAs<FunctionProtoType>();
513 
514   // extern "C" functions can hold entities that must be mangled.
515   // As it stands, these functions still need to get expressed in the full
516   // external name.  They have their class and type omitted, replaced with '9'.
517   if (ShouldMangle) {
518     // We would like to mangle all extern "C" functions using this additional
519     // component but this would break compatibility with MSVC's behavior.
520     // Instead, do this when we know that compatibility isn't important (in
521     // other words, when it is an overloaded extern "C" function).
522     if (FD->isExternC() && FD->hasAttr<OverloadableAttr>())
523       Out << "$$J0";
524 
525     mangleFunctionClass(FD);
526 
527     mangleFunctionType(FT, FD, false, false);
528   } else {
529     Out << '9';
530   }
531 }
532 
533 void MicrosoftCXXNameMangler::mangleVariableEncoding(const VarDecl *VD) {
534   // <type-encoding> ::= <storage-class> <variable-type>
535   // <storage-class> ::= 0  # private static member
536   //                 ::= 1  # protected static member
537   //                 ::= 2  # public static member
538   //                 ::= 3  # global
539   //                 ::= 4  # static local
540 
541   // The first character in the encoding (after the name) is the storage class.
542   if (VD->isStaticDataMember()) {
543     // If it's a static member, it also encodes the access level.
544     switch (VD->getAccess()) {
545       default:
546       case AS_private: Out << '0'; break;
547       case AS_protected: Out << '1'; break;
548       case AS_public: Out << '2'; break;
549     }
550   }
551   else if (!VD->isStaticLocal())
552     Out << '3';
553   else
554     Out << '4';
555   // Now mangle the type.
556   // <variable-type> ::= <type> <cvr-qualifiers>
557   //                 ::= <type> <pointee-cvr-qualifiers> # pointers, references
558   // Pointers and references are odd. The type of 'int * const foo;' gets
559   // mangled as 'QAHA' instead of 'PAHB', for example.
560   SourceRange SR = VD->getSourceRange();
561   QualType Ty = VD->getType();
562   if (Ty->isPointerType() || Ty->isReferenceType() ||
563       Ty->isMemberPointerType()) {
564     mangleType(Ty, SR, QMM_Drop);
565     manglePointerExtQualifiers(
566         Ty.getDesugaredType(getASTContext()).getLocalQualifiers(), QualType());
567     if (const MemberPointerType *MPT = Ty->getAs<MemberPointerType>()) {
568       mangleQualifiers(MPT->getPointeeType().getQualifiers(), true);
569       // Member pointers are suffixed with a back reference to the member
570       // pointer's class name.
571       mangleName(MPT->getClass()->getAsCXXRecordDecl());
572     } else
573       mangleQualifiers(Ty->getPointeeType().getQualifiers(), false);
574   } else if (const ArrayType *AT = getASTContext().getAsArrayType(Ty)) {
575     // Global arrays are funny, too.
576     mangleDecayedArrayType(AT);
577     if (AT->getElementType()->isArrayType())
578       Out << 'A';
579     else
580       mangleQualifiers(Ty.getQualifiers(), false);
581   } else {
582     mangleType(Ty, SR, QMM_Drop);
583     mangleQualifiers(Ty.getQualifiers(), false);
584   }
585 }
586 
587 void MicrosoftCXXNameMangler::mangleMemberDataPointer(const CXXRecordDecl *RD,
588                                                       const ValueDecl *VD) {
589   // <member-data-pointer> ::= <integer-literal>
590   //                       ::= $F <number> <number>
591   //                       ::= $G <number> <number> <number>
592 
593   int64_t FieldOffset;
594   int64_t VBTableOffset;
595   MSInheritanceAttr::Spelling IM = RD->getMSInheritanceModel();
596   if (VD) {
597     FieldOffset = getASTContext().getFieldOffset(VD);
598     assert(FieldOffset % getASTContext().getCharWidth() == 0 &&
599            "cannot take address of bitfield");
600     FieldOffset /= getASTContext().getCharWidth();
601 
602     VBTableOffset = 0;
603 
604     if (IM == MSInheritanceAttr::Keyword_virtual_inheritance)
605       FieldOffset -= getASTContext().getOffsetOfBaseWithVBPtr(RD).getQuantity();
606   } else {
607     FieldOffset = RD->nullFieldOffsetIsZero() ? 0 : -1;
608 
609     VBTableOffset = -1;
610   }
611 
612   char Code = '\0';
613   switch (IM) {
614   case MSInheritanceAttr::Keyword_single_inheritance:      Code = '0'; break;
615   case MSInheritanceAttr::Keyword_multiple_inheritance:    Code = '0'; break;
616   case MSInheritanceAttr::Keyword_virtual_inheritance:     Code = 'F'; break;
617   case MSInheritanceAttr::Keyword_unspecified_inheritance: Code = 'G'; break;
618   }
619 
620   Out << '$' << Code;
621 
622   mangleNumber(FieldOffset);
623 
624   // The C++ standard doesn't allow base-to-derived member pointer conversions
625   // in template parameter contexts, so the vbptr offset of data member pointers
626   // is always zero.
627   if (MSInheritanceAttr::hasVBPtrOffsetField(IM))
628     mangleNumber(0);
629   if (MSInheritanceAttr::hasVBTableOffsetField(IM))
630     mangleNumber(VBTableOffset);
631 }
632 
633 void
634 MicrosoftCXXNameMangler::mangleMemberFunctionPointer(const CXXRecordDecl *RD,
635                                                      const CXXMethodDecl *MD) {
636   // <member-function-pointer> ::= $1? <name>
637   //                           ::= $H? <name> <number>
638   //                           ::= $I? <name> <number> <number>
639   //                           ::= $J? <name> <number> <number> <number>
640 
641   MSInheritanceAttr::Spelling IM = RD->getMSInheritanceModel();
642 
643   char Code = '\0';
644   switch (IM) {
645   case MSInheritanceAttr::Keyword_single_inheritance:      Code = '1'; break;
646   case MSInheritanceAttr::Keyword_multiple_inheritance:    Code = 'H'; break;
647   case MSInheritanceAttr::Keyword_virtual_inheritance:     Code = 'I'; break;
648   case MSInheritanceAttr::Keyword_unspecified_inheritance: Code = 'J'; break;
649   }
650 
651   // If non-virtual, mangle the name.  If virtual, mangle as a virtual memptr
652   // thunk.
653   uint64_t NVOffset = 0;
654   uint64_t VBTableOffset = 0;
655   uint64_t VBPtrOffset = 0;
656   if (MD) {
657     Out << '$' << Code << '?';
658     if (MD->isVirtual()) {
659       MicrosoftVTableContext *VTContext =
660           cast<MicrosoftVTableContext>(getASTContext().getVTableContext());
661       MethodVFTableLocation ML =
662           VTContext->getMethodVFTableLocation(GlobalDecl(MD));
663       mangleVirtualMemPtrThunk(MD, ML);
664       NVOffset = ML.VFPtrOffset.getQuantity();
665       VBTableOffset = ML.VBTableIndex * 4;
666       if (ML.VBase) {
667         const ASTRecordLayout &Layout = getASTContext().getASTRecordLayout(RD);
668         VBPtrOffset = Layout.getVBPtrOffset().getQuantity();
669       }
670     } else {
671       mangleName(MD);
672       mangleFunctionEncoding(MD, /*ShouldMangle=*/true);
673     }
674 
675     if (VBTableOffset == 0 &&
676         IM == MSInheritanceAttr::Keyword_virtual_inheritance)
677       NVOffset -= getASTContext().getOffsetOfBaseWithVBPtr(RD).getQuantity();
678   } else {
679     // Null single inheritance member functions are encoded as a simple nullptr.
680     if (IM == MSInheritanceAttr::Keyword_single_inheritance) {
681       Out << "$0A@";
682       return;
683     }
684     if (IM == MSInheritanceAttr::Keyword_unspecified_inheritance)
685       VBTableOffset = -1;
686     Out << '$' << Code;
687   }
688 
689   if (MSInheritanceAttr::hasNVOffsetField(/*IsMemberFunction=*/true, IM))
690     mangleNumber(static_cast<uint32_t>(NVOffset));
691   if (MSInheritanceAttr::hasVBPtrOffsetField(IM))
692     mangleNumber(VBPtrOffset);
693   if (MSInheritanceAttr::hasVBTableOffsetField(IM))
694     mangleNumber(VBTableOffset);
695 }
696 
697 void MicrosoftCXXNameMangler::mangleVirtualMemPtrThunk(
698     const CXXMethodDecl *MD, const MethodVFTableLocation &ML) {
699   // Get the vftable offset.
700   CharUnits PointerWidth = getASTContext().toCharUnitsFromBits(
701       getASTContext().getTargetInfo().getPointerWidth(0));
702   uint64_t OffsetInVFTable = ML.Index * PointerWidth.getQuantity();
703 
704   Out << "?_9";
705   mangleName(MD->getParent());
706   Out << "$B";
707   mangleNumber(OffsetInVFTable);
708   Out << 'A';
709   mangleCallingConvention(MD->getType()->getAs<FunctionProtoType>());
710 }
711 
712 void MicrosoftCXXNameMangler::mangleName(const NamedDecl *ND) {
713   // <name> ::= <unscoped-name> {[<named-scope>]+ | [<nested-name>]}? @
714 
715   // Always start with the unqualified name.
716   mangleUnqualifiedName(ND);
717 
718   mangleNestedName(ND);
719 
720   // Terminate the whole name with an '@'.
721   Out << '@';
722 }
723 
724 void MicrosoftCXXNameMangler::mangleNumber(int64_t Number) {
725   // <non-negative integer> ::= A@              # when Number == 0
726   //                        ::= <decimal digit> # when 1 <= Number <= 10
727   //                        ::= <hex digit>+ @  # when Number >= 10
728   //
729   // <number>               ::= [?] <non-negative integer>
730 
731   uint64_t Value = static_cast<uint64_t>(Number);
732   if (Number < 0) {
733     Value = -Value;
734     Out << '?';
735   }
736 
737   if (Value == 0)
738     Out << "A@";
739   else if (Value >= 1 && Value <= 10)
740     Out << (Value - 1);
741   else {
742     // Numbers that are not encoded as decimal digits are represented as nibbles
743     // in the range of ASCII characters 'A' to 'P'.
744     // The number 0x123450 would be encoded as 'BCDEFA'
745     char EncodedNumberBuffer[sizeof(uint64_t) * 2];
746     MutableArrayRef<char> BufferRef(EncodedNumberBuffer);
747     MutableArrayRef<char>::reverse_iterator I = BufferRef.rbegin();
748     for (; Value != 0; Value >>= 4)
749       *I++ = 'A' + (Value & 0xf);
750     Out.write(I.base(), I - BufferRef.rbegin());
751     Out << '@';
752   }
753 }
754 
755 static const TemplateDecl *
756 isTemplate(const NamedDecl *ND, const TemplateArgumentList *&TemplateArgs) {
757   // Check if we have a function template.
758   if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
759     if (const TemplateDecl *TD = FD->getPrimaryTemplate()) {
760       TemplateArgs = FD->getTemplateSpecializationArgs();
761       return TD;
762     }
763   }
764 
765   // Check if we have a class template.
766   if (const ClassTemplateSpecializationDecl *Spec =
767           dyn_cast<ClassTemplateSpecializationDecl>(ND)) {
768     TemplateArgs = &Spec->getTemplateArgs();
769     return Spec->getSpecializedTemplate();
770   }
771 
772   // Check if we have a variable template.
773   if (const VarTemplateSpecializationDecl *Spec =
774           dyn_cast<VarTemplateSpecializationDecl>(ND)) {
775     TemplateArgs = &Spec->getTemplateArgs();
776     return Spec->getSpecializedTemplate();
777   }
778 
779   return nullptr;
780 }
781 
782 void MicrosoftCXXNameMangler::mangleUnqualifiedName(const NamedDecl *ND,
783                                                     DeclarationName Name) {
784   //  <unqualified-name> ::= <operator-name>
785   //                     ::= <ctor-dtor-name>
786   //                     ::= <source-name>
787   //                     ::= <template-name>
788 
789   // Check if we have a template.
790   const TemplateArgumentList *TemplateArgs = nullptr;
791   if (const TemplateDecl *TD = isTemplate(ND, TemplateArgs)) {
792     // Function templates aren't considered for name back referencing.  This
793     // makes sense since function templates aren't likely to occur multiple
794     // times in a symbol.
795     if (isa<FunctionTemplateDecl>(TD)) {
796       mangleTemplateInstantiationName(TD, *TemplateArgs);
797       Out << '@';
798       return;
799     }
800 
801     // Here comes the tricky thing: if we need to mangle something like
802     //   void foo(A::X<Y>, B::X<Y>),
803     // the X<Y> part is aliased. However, if you need to mangle
804     //   void foo(A::X<A::Y>, A::X<B::Y>),
805     // the A::X<> part is not aliased.
806     // That is, from the mangler's perspective we have a structure like this:
807     //   namespace[s] -> type[ -> template-parameters]
808     // but from the Clang perspective we have
809     //   type [ -> template-parameters]
810     //      \-> namespace[s]
811     // What we do is we create a new mangler, mangle the same type (without
812     // a namespace suffix) to a string using the extra mangler and then use
813     // the mangled type name as a key to check the mangling of different types
814     // for aliasing.
815 
816     // It's important to key cache reads off ND, not TD -- the same TD can
817     // be used with different TemplateArgs, but ND uniquely identifies
818     // TD / TemplateArg pairs.
819     ArgBackRefMap::iterator Found = TemplateArgBackReferences.find(ND);
820     if (Found == TemplateArgBackReferences.end()) {
821 
822       TemplateArgStringMap::iterator Found = TemplateArgStrings.find(ND);
823       if (Found == TemplateArgStrings.end()) {
824         // Mangle full template name into temporary buffer.
825         llvm::SmallString<64> TemplateMangling;
826         llvm::raw_svector_ostream Stream(TemplateMangling);
827         MicrosoftCXXNameMangler Extra(Context, Stream);
828         Extra.mangleTemplateInstantiationName(TD, *TemplateArgs);
829 
830         // Use the string backref vector to possibly get a back reference.
831         mangleSourceName(TemplateMangling);
832 
833         // Memoize back reference for this type if one exist, else memoize
834         // the mangling itself.
835         BackRefVec::iterator StringFound =
836             llvm::find(NameBackReferences, TemplateMangling);
837         if (StringFound != NameBackReferences.end()) {
838           TemplateArgBackReferences[ND] =
839               StringFound - NameBackReferences.begin();
840         } else {
841           TemplateArgStrings[ND] =
842               TemplateArgStringStorage.save(TemplateMangling.str());
843         }
844       } else {
845         Out << Found->second; // Outputs a StringRef.
846       }
847     } else {
848       Out << Found->second; // Outputs a back reference (an int).
849     }
850     return;
851   }
852 
853   switch (Name.getNameKind()) {
854     case DeclarationName::Identifier: {
855       if (const IdentifierInfo *II = Name.getAsIdentifierInfo()) {
856         mangleSourceName(II->getName());
857         break;
858       }
859 
860       // Otherwise, an anonymous entity.  We must have a declaration.
861       assert(ND && "mangling empty name without declaration");
862 
863       if (const NamespaceDecl *NS = dyn_cast<NamespaceDecl>(ND)) {
864         if (NS->isAnonymousNamespace()) {
865           Out << "?A0x" << Context.getAnonymousNamespaceHash() << '@';
866           break;
867         }
868       }
869 
870       if (const DecompositionDecl *DD = dyn_cast<DecompositionDecl>(ND)) {
871         // Decomposition declarations are considered anonymous, and get
872         // numbered with a $S prefix.
873         llvm::SmallString<64> Name("$S");
874         // Get a unique id for the anonymous struct.
875         Name += llvm::utostr(Context.getAnonymousStructId(DD) + 1);
876         mangleSourceName(Name);
877         break;
878       }
879 
880       if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
881         // We must have an anonymous union or struct declaration.
882         const CXXRecordDecl *RD = VD->getType()->getAsCXXRecordDecl();
883         assert(RD && "expected variable decl to have a record type");
884         // Anonymous types with no tag or typedef get the name of their
885         // declarator mangled in.  If they have no declarator, number them with
886         // a $S prefix.
887         llvm::SmallString<64> Name("$S");
888         // Get a unique id for the anonymous struct.
889         Name += llvm::utostr(Context.getAnonymousStructId(RD) + 1);
890         mangleSourceName(Name.str());
891         break;
892       }
893 
894       // We must have an anonymous struct.
895       const TagDecl *TD = cast<TagDecl>(ND);
896       if (const TypedefNameDecl *D = TD->getTypedefNameForAnonDecl()) {
897         assert(TD->getDeclContext() == D->getDeclContext() &&
898                "Typedef should not be in another decl context!");
899         assert(D->getDeclName().getAsIdentifierInfo() &&
900                "Typedef was not named!");
901         mangleSourceName(D->getDeclName().getAsIdentifierInfo()->getName());
902         break;
903       }
904 
905       if (const CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(TD)) {
906         if (Record->isLambda()) {
907           llvm::SmallString<10> Name("<lambda_");
908 
909           Decl *LambdaContextDecl = Record->getLambdaContextDecl();
910           unsigned LambdaManglingNumber = Record->getLambdaManglingNumber();
911           unsigned LambdaId;
912           const ParmVarDecl *Parm =
913               dyn_cast_or_null<ParmVarDecl>(LambdaContextDecl);
914           const FunctionDecl *Func =
915               Parm ? dyn_cast<FunctionDecl>(Parm->getDeclContext()) : nullptr;
916 
917           if (Func) {
918             unsigned DefaultArgNo =
919                 Func->getNumParams() - Parm->getFunctionScopeIndex();
920             Name += llvm::utostr(DefaultArgNo);
921             Name += "_";
922           }
923 
924           if (LambdaManglingNumber)
925             LambdaId = LambdaManglingNumber;
926           else
927             LambdaId = Context.getLambdaId(Record);
928 
929           Name += llvm::utostr(LambdaId);
930           Name += ">";
931 
932           mangleSourceName(Name);
933 
934           // If the context of a closure type is an initializer for a class
935           // member (static or nonstatic), it is encoded in a qualified name.
936           if (LambdaManglingNumber && LambdaContextDecl) {
937             if ((isa<VarDecl>(LambdaContextDecl) ||
938                  isa<FieldDecl>(LambdaContextDecl)) &&
939                 LambdaContextDecl->getDeclContext()->isRecord()) {
940               mangleUnqualifiedName(cast<NamedDecl>(LambdaContextDecl));
941             }
942           }
943           break;
944         }
945       }
946 
947       llvm::SmallString<64> Name;
948       if (DeclaratorDecl *DD =
949               Context.getASTContext().getDeclaratorForUnnamedTagDecl(TD)) {
950         // Anonymous types without a name for linkage purposes have their
951         // declarator mangled in if they have one.
952         Name += "<unnamed-type-";
953         Name += DD->getName();
954       } else if (TypedefNameDecl *TND =
955                      Context.getASTContext().getTypedefNameForUnnamedTagDecl(
956                          TD)) {
957         // Anonymous types without a name for linkage purposes have their
958         // associate typedef mangled in if they have one.
959         Name += "<unnamed-type-";
960         Name += TND->getName();
961       } else if (isa<EnumDecl>(TD) &&
962                  cast<EnumDecl>(TD)->enumerator_begin() !=
963                      cast<EnumDecl>(TD)->enumerator_end()) {
964         // Anonymous non-empty enums mangle in the first enumerator.
965         auto *ED = cast<EnumDecl>(TD);
966         Name += "<unnamed-enum-";
967         Name += ED->enumerator_begin()->getName();
968       } else {
969         // Otherwise, number the types using a $S prefix.
970         Name += "<unnamed-type-$S";
971         Name += llvm::utostr(Context.getAnonymousStructId(TD) + 1);
972       }
973       Name += ">";
974       mangleSourceName(Name.str());
975       break;
976     }
977 
978     case DeclarationName::ObjCZeroArgSelector:
979     case DeclarationName::ObjCOneArgSelector:
980     case DeclarationName::ObjCMultiArgSelector: {
981       // This is reachable only when constructing an outlined SEH finally
982       // block.  Nothing depends on this mangling and it's used only with
983       // functinos with internal linkage.
984       llvm::SmallString<64> Name;
985       mangleSourceName(Name.str());
986       break;
987     }
988 
989     case DeclarationName::CXXConstructorName:
990       if (isStructorDecl(ND)) {
991         if (StructorType == Ctor_CopyingClosure) {
992           Out << "?_O";
993           return;
994         }
995         if (StructorType == Ctor_DefaultClosure) {
996           Out << "?_F";
997           return;
998         }
999       }
1000       Out << "?0";
1001       return;
1002 
1003     case DeclarationName::CXXDestructorName:
1004       if (isStructorDecl(ND))
1005         // If the named decl is the C++ destructor we're mangling,
1006         // use the type we were given.
1007         mangleCXXDtorType(static_cast<CXXDtorType>(StructorType));
1008       else
1009         // Otherwise, use the base destructor name. This is relevant if a
1010         // class with a destructor is declared within a destructor.
1011         mangleCXXDtorType(Dtor_Base);
1012       break;
1013 
1014     case DeclarationName::CXXConversionFunctionName:
1015       // <operator-name> ::= ?B # (cast)
1016       // The target type is encoded as the return type.
1017       Out << "?B";
1018       break;
1019 
1020     case DeclarationName::CXXOperatorName:
1021       mangleOperatorName(Name.getCXXOverloadedOperator(), ND->getLocation());
1022       break;
1023 
1024     case DeclarationName::CXXLiteralOperatorName: {
1025       Out << "?__K";
1026       mangleSourceName(Name.getCXXLiteralIdentifier()->getName());
1027       break;
1028     }
1029 
1030     case DeclarationName::CXXDeductionGuideName:
1031       llvm_unreachable("Can't mangle a deduction guide name!");
1032 
1033     case DeclarationName::CXXUsingDirective:
1034       llvm_unreachable("Can't mangle a using directive name!");
1035   }
1036 }
1037 
1038 // <postfix> ::= <unqualified-name> [<postfix>]
1039 //           ::= <substitution> [<postfix>]
1040 void MicrosoftCXXNameMangler::mangleNestedName(const NamedDecl *ND) {
1041   const DeclContext *DC = getEffectiveDeclContext(ND);
1042   while (!DC->isTranslationUnit()) {
1043     if (isa<TagDecl>(ND) || isa<VarDecl>(ND)) {
1044       unsigned Disc;
1045       if (Context.getNextDiscriminator(ND, Disc)) {
1046         Out << '?';
1047         mangleNumber(Disc);
1048         Out << '?';
1049       }
1050     }
1051 
1052     if (const BlockDecl *BD = dyn_cast<BlockDecl>(DC)) {
1053       auto Discriminate =
1054           [](StringRef Name, const unsigned Discriminator,
1055              const unsigned ParameterDiscriminator) -> std::string {
1056         std::string Buffer;
1057         llvm::raw_string_ostream Stream(Buffer);
1058         Stream << Name;
1059         if (Discriminator)
1060           Stream << '_' << Discriminator;
1061         if (ParameterDiscriminator)
1062           Stream << '_' << ParameterDiscriminator;
1063         return Stream.str();
1064       };
1065 
1066       unsigned Discriminator = BD->getBlockManglingNumber();
1067       if (!Discriminator)
1068         Discriminator = Context.getBlockId(BD, /*Local=*/false);
1069 
1070       // Mangle the parameter position as a discriminator to deal with unnamed
1071       // parameters.  Rather than mangling the unqualified parameter name,
1072       // always use the position to give a uniform mangling.
1073       unsigned ParameterDiscriminator = 0;
1074       if (const auto *MC = BD->getBlockManglingContextDecl())
1075         if (const auto *P = dyn_cast<ParmVarDecl>(MC))
1076           if (const auto *F = dyn_cast<FunctionDecl>(P->getDeclContext()))
1077             ParameterDiscriminator =
1078                 F->getNumParams() - P->getFunctionScopeIndex();
1079 
1080       DC = getEffectiveDeclContext(BD);
1081 
1082       Out << '?';
1083       mangleSourceName(Discriminate("_block_invoke", Discriminator,
1084                                     ParameterDiscriminator));
1085       // If we have a block mangling context, encode that now.  This allows us
1086       // to discriminate between named static data initializers in the same
1087       // scope.  This is handled differently from parameters, which use
1088       // positions to discriminate between multiple instances.
1089       if (const auto *MC = BD->getBlockManglingContextDecl())
1090         if (!isa<ParmVarDecl>(MC))
1091           if (const auto *ND = dyn_cast<NamedDecl>(MC))
1092             mangleUnqualifiedName(ND);
1093       // MS ABI and Itanium manglings are in inverted scopes.  In the case of a
1094       // RecordDecl, mangle the entire scope hierarchy at this point rather than
1095       // just the unqualified name to get the ordering correct.
1096       if (const auto *RD = dyn_cast<RecordDecl>(DC))
1097         mangleName(RD);
1098       else
1099         Out << '@';
1100       // void __cdecl
1101       Out << "YAX";
1102       // struct __block_literal *
1103       Out << 'P';
1104       // __ptr64
1105       if (PointersAre64Bit)
1106         Out << 'E';
1107       Out << 'A';
1108       mangleArtificialTagType(TTK_Struct,
1109                              Discriminate("__block_literal", Discriminator,
1110                                           ParameterDiscriminator));
1111       Out << "@Z";
1112 
1113       // If the effective context was a Record, we have fully mangled the
1114       // qualified name and do not need to continue.
1115       if (isa<RecordDecl>(DC))
1116         break;
1117       continue;
1118     } else if (const ObjCMethodDecl *Method = dyn_cast<ObjCMethodDecl>(DC)) {
1119       mangleObjCMethodName(Method);
1120     } else if (isa<NamedDecl>(DC)) {
1121       ND = cast<NamedDecl>(DC);
1122       if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
1123         mangle(FD, "?");
1124         break;
1125       } else {
1126         mangleUnqualifiedName(ND);
1127         // Lambdas in default arguments conceptually belong to the function the
1128         // parameter corresponds to.
1129         if (const auto *LDADC = getLambdaDefaultArgumentDeclContext(ND)) {
1130           DC = LDADC;
1131           continue;
1132         }
1133       }
1134     }
1135     DC = DC->getParent();
1136   }
1137 }
1138 
1139 void MicrosoftCXXNameMangler::mangleCXXDtorType(CXXDtorType T) {
1140   // Microsoft uses the names on the case labels for these dtor variants.  Clang
1141   // uses the Itanium terminology internally.  Everything in this ABI delegates
1142   // towards the base dtor.
1143   switch (T) {
1144   // <operator-name> ::= ?1  # destructor
1145   case Dtor_Base: Out << "?1"; return;
1146   // <operator-name> ::= ?_D # vbase destructor
1147   case Dtor_Complete: Out << "?_D"; return;
1148   // <operator-name> ::= ?_G # scalar deleting destructor
1149   case Dtor_Deleting: Out << "?_G"; return;
1150   // <operator-name> ::= ?_E # vector deleting destructor
1151   // FIXME: Add a vector deleting dtor type.  It goes in the vtable, so we need
1152   // it.
1153   case Dtor_Comdat:
1154     llvm_unreachable("not expecting a COMDAT");
1155   }
1156   llvm_unreachable("Unsupported dtor type?");
1157 }
1158 
1159 void MicrosoftCXXNameMangler::mangleOperatorName(OverloadedOperatorKind OO,
1160                                                  SourceLocation Loc) {
1161   switch (OO) {
1162   //                     ?0 # constructor
1163   //                     ?1 # destructor
1164   // <operator-name> ::= ?2 # new
1165   case OO_New: Out << "?2"; break;
1166   // <operator-name> ::= ?3 # delete
1167   case OO_Delete: Out << "?3"; break;
1168   // <operator-name> ::= ?4 # =
1169   case OO_Equal: Out << "?4"; break;
1170   // <operator-name> ::= ?5 # >>
1171   case OO_GreaterGreater: Out << "?5"; break;
1172   // <operator-name> ::= ?6 # <<
1173   case OO_LessLess: Out << "?6"; break;
1174   // <operator-name> ::= ?7 # !
1175   case OO_Exclaim: Out << "?7"; break;
1176   // <operator-name> ::= ?8 # ==
1177   case OO_EqualEqual: Out << "?8"; break;
1178   // <operator-name> ::= ?9 # !=
1179   case OO_ExclaimEqual: Out << "?9"; break;
1180   // <operator-name> ::= ?A # []
1181   case OO_Subscript: Out << "?A"; break;
1182   //                     ?B # conversion
1183   // <operator-name> ::= ?C # ->
1184   case OO_Arrow: Out << "?C"; break;
1185   // <operator-name> ::= ?D # *
1186   case OO_Star: Out << "?D"; break;
1187   // <operator-name> ::= ?E # ++
1188   case OO_PlusPlus: Out << "?E"; break;
1189   // <operator-name> ::= ?F # --
1190   case OO_MinusMinus: Out << "?F"; break;
1191   // <operator-name> ::= ?G # -
1192   case OO_Minus: Out << "?G"; break;
1193   // <operator-name> ::= ?H # +
1194   case OO_Plus: Out << "?H"; break;
1195   // <operator-name> ::= ?I # &
1196   case OO_Amp: Out << "?I"; break;
1197   // <operator-name> ::= ?J # ->*
1198   case OO_ArrowStar: Out << "?J"; break;
1199   // <operator-name> ::= ?K # /
1200   case OO_Slash: Out << "?K"; break;
1201   // <operator-name> ::= ?L # %
1202   case OO_Percent: Out << "?L"; break;
1203   // <operator-name> ::= ?M # <
1204   case OO_Less: Out << "?M"; break;
1205   // <operator-name> ::= ?N # <=
1206   case OO_LessEqual: Out << "?N"; break;
1207   // <operator-name> ::= ?O # >
1208   case OO_Greater: Out << "?O"; break;
1209   // <operator-name> ::= ?P # >=
1210   case OO_GreaterEqual: Out << "?P"; break;
1211   // <operator-name> ::= ?Q # ,
1212   case OO_Comma: Out << "?Q"; break;
1213   // <operator-name> ::= ?R # ()
1214   case OO_Call: Out << "?R"; break;
1215   // <operator-name> ::= ?S # ~
1216   case OO_Tilde: Out << "?S"; break;
1217   // <operator-name> ::= ?T # ^
1218   case OO_Caret: Out << "?T"; break;
1219   // <operator-name> ::= ?U # |
1220   case OO_Pipe: Out << "?U"; break;
1221   // <operator-name> ::= ?V # &&
1222   case OO_AmpAmp: Out << "?V"; break;
1223   // <operator-name> ::= ?W # ||
1224   case OO_PipePipe: Out << "?W"; break;
1225   // <operator-name> ::= ?X # *=
1226   case OO_StarEqual: Out << "?X"; break;
1227   // <operator-name> ::= ?Y # +=
1228   case OO_PlusEqual: Out << "?Y"; break;
1229   // <operator-name> ::= ?Z # -=
1230   case OO_MinusEqual: Out << "?Z"; break;
1231   // <operator-name> ::= ?_0 # /=
1232   case OO_SlashEqual: Out << "?_0"; break;
1233   // <operator-name> ::= ?_1 # %=
1234   case OO_PercentEqual: Out << "?_1"; break;
1235   // <operator-name> ::= ?_2 # >>=
1236   case OO_GreaterGreaterEqual: Out << "?_2"; break;
1237   // <operator-name> ::= ?_3 # <<=
1238   case OO_LessLessEqual: Out << "?_3"; break;
1239   // <operator-name> ::= ?_4 # &=
1240   case OO_AmpEqual: Out << "?_4"; break;
1241   // <operator-name> ::= ?_5 # |=
1242   case OO_PipeEqual: Out << "?_5"; break;
1243   // <operator-name> ::= ?_6 # ^=
1244   case OO_CaretEqual: Out << "?_6"; break;
1245   //                     ?_7 # vftable
1246   //                     ?_8 # vbtable
1247   //                     ?_9 # vcall
1248   //                     ?_A # typeof
1249   //                     ?_B # local static guard
1250   //                     ?_C # string
1251   //                     ?_D # vbase destructor
1252   //                     ?_E # vector deleting destructor
1253   //                     ?_F # default constructor closure
1254   //                     ?_G # scalar deleting destructor
1255   //                     ?_H # vector constructor iterator
1256   //                     ?_I # vector destructor iterator
1257   //                     ?_J # vector vbase constructor iterator
1258   //                     ?_K # virtual displacement map
1259   //                     ?_L # eh vector constructor iterator
1260   //                     ?_M # eh vector destructor iterator
1261   //                     ?_N # eh vector vbase constructor iterator
1262   //                     ?_O # copy constructor closure
1263   //                     ?_P<name> # udt returning <name>
1264   //                     ?_Q # <unknown>
1265   //                     ?_R0 # RTTI Type Descriptor
1266   //                     ?_R1 # RTTI Base Class Descriptor at (a,b,c,d)
1267   //                     ?_R2 # RTTI Base Class Array
1268   //                     ?_R3 # RTTI Class Hierarchy Descriptor
1269   //                     ?_R4 # RTTI Complete Object Locator
1270   //                     ?_S # local vftable
1271   //                     ?_T # local vftable constructor closure
1272   // <operator-name> ::= ?_U # new[]
1273   case OO_Array_New: Out << "?_U"; break;
1274   // <operator-name> ::= ?_V # delete[]
1275   case OO_Array_Delete: Out << "?_V"; break;
1276   // <operator-name> ::= ?__L # co_await
1277   case OO_Coawait: Out << "?__L"; break;
1278   // <operator-name> ::= ?__M # <=>
1279   case OO_Spaceship: Out << "?__M"; break;
1280 
1281   case OO_Conditional: {
1282     DiagnosticsEngine &Diags = Context.getDiags();
1283     unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
1284       "cannot mangle this conditional operator yet");
1285     Diags.Report(Loc, DiagID);
1286     break;
1287   }
1288 
1289   case OO_None:
1290   case NUM_OVERLOADED_OPERATORS:
1291     llvm_unreachable("Not an overloaded operator");
1292   }
1293 }
1294 
1295 void MicrosoftCXXNameMangler::mangleSourceName(StringRef Name) {
1296   // <source name> ::= <identifier> @
1297   BackRefVec::iterator Found = llvm::find(NameBackReferences, Name);
1298   if (Found == NameBackReferences.end()) {
1299     if (NameBackReferences.size() < 10)
1300       NameBackReferences.push_back(Name);
1301     Out << Name << '@';
1302   } else {
1303     Out << (Found - NameBackReferences.begin());
1304   }
1305 }
1306 
1307 void MicrosoftCXXNameMangler::mangleObjCMethodName(const ObjCMethodDecl *MD) {
1308   Context.mangleObjCMethodName(MD, Out);
1309 }
1310 
1311 void MicrosoftCXXNameMangler::mangleTemplateInstantiationName(
1312     const TemplateDecl *TD, const TemplateArgumentList &TemplateArgs) {
1313   // <template-name> ::= <unscoped-template-name> <template-args>
1314   //                 ::= <substitution>
1315   // Always start with the unqualified name.
1316 
1317   // Templates have their own context for back references.
1318   ArgBackRefMap OuterFunArgsContext;
1319   ArgBackRefMap OuterTemplateArgsContext;
1320   BackRefVec OuterTemplateContext;
1321   PassObjectSizeArgsSet OuterPassObjectSizeArgs;
1322   NameBackReferences.swap(OuterTemplateContext);
1323   FunArgBackReferences.swap(OuterFunArgsContext);
1324   TemplateArgBackReferences.swap(OuterTemplateArgsContext);
1325   PassObjectSizeArgs.swap(OuterPassObjectSizeArgs);
1326 
1327   mangleUnscopedTemplateName(TD);
1328   mangleTemplateArgs(TD, TemplateArgs);
1329 
1330   // Restore the previous back reference contexts.
1331   NameBackReferences.swap(OuterTemplateContext);
1332   FunArgBackReferences.swap(OuterFunArgsContext);
1333   TemplateArgBackReferences.swap(OuterTemplateArgsContext);
1334   PassObjectSizeArgs.swap(OuterPassObjectSizeArgs);
1335 }
1336 
1337 void
1338 MicrosoftCXXNameMangler::mangleUnscopedTemplateName(const TemplateDecl *TD) {
1339   // <unscoped-template-name> ::= ?$ <unqualified-name>
1340   Out << "?$";
1341   mangleUnqualifiedName(TD);
1342 }
1343 
1344 void MicrosoftCXXNameMangler::mangleIntegerLiteral(const llvm::APSInt &Value,
1345                                                    bool IsBoolean) {
1346   // <integer-literal> ::= $0 <number>
1347   Out << "$0";
1348   // Make sure booleans are encoded as 0/1.
1349   if (IsBoolean && Value.getBoolValue())
1350     mangleNumber(1);
1351   else if (Value.isSigned())
1352     mangleNumber(Value.getSExtValue());
1353   else
1354     mangleNumber(Value.getZExtValue());
1355 }
1356 
1357 void MicrosoftCXXNameMangler::mangleExpression(const Expr *E) {
1358   // See if this is a constant expression.
1359   llvm::APSInt Value;
1360   if (E->isIntegerConstantExpr(Value, Context.getASTContext())) {
1361     mangleIntegerLiteral(Value, E->getType()->isBooleanType());
1362     return;
1363   }
1364 
1365   // Look through no-op casts like template parameter substitutions.
1366   E = E->IgnoreParenNoopCasts(Context.getASTContext());
1367 
1368   const CXXUuidofExpr *UE = nullptr;
1369   if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
1370     if (UO->getOpcode() == UO_AddrOf)
1371       UE = dyn_cast<CXXUuidofExpr>(UO->getSubExpr());
1372   } else
1373     UE = dyn_cast<CXXUuidofExpr>(E);
1374 
1375   if (UE) {
1376     // If we had to peek through an address-of operator, treat this like we are
1377     // dealing with a pointer type.  Otherwise, treat it like a const reference.
1378     //
1379     // N.B. This matches up with the handling of TemplateArgument::Declaration
1380     // in mangleTemplateArg
1381     if (UE == E)
1382       Out << "$E?";
1383     else
1384       Out << "$1?";
1385 
1386     // This CXXUuidofExpr is mangled as-if it were actually a VarDecl from
1387     // const __s_GUID _GUID_{lower case UUID with underscores}
1388     StringRef Uuid = UE->getUuidStr();
1389     std::string Name = "_GUID_" + Uuid.lower();
1390     std::replace(Name.begin(), Name.end(), '-', '_');
1391 
1392     mangleSourceName(Name);
1393     // Terminate the whole name with an '@'.
1394     Out << '@';
1395     // It's a global variable.
1396     Out << '3';
1397     // It's a struct called __s_GUID.
1398     mangleArtificialTagType(TTK_Struct, "__s_GUID");
1399     // It's const.
1400     Out << 'B';
1401     return;
1402   }
1403 
1404   // As bad as this diagnostic is, it's better than crashing.
1405   DiagnosticsEngine &Diags = Context.getDiags();
1406   unsigned DiagID = Diags.getCustomDiagID(
1407       DiagnosticsEngine::Error, "cannot yet mangle expression type %0");
1408   Diags.Report(E->getExprLoc(), DiagID) << E->getStmtClassName()
1409                                         << E->getSourceRange();
1410 }
1411 
1412 void MicrosoftCXXNameMangler::mangleTemplateArgs(
1413     const TemplateDecl *TD, const TemplateArgumentList &TemplateArgs) {
1414   // <template-args> ::= <template-arg>+
1415   const TemplateParameterList *TPL = TD->getTemplateParameters();
1416   assert(TPL->size() == TemplateArgs.size() &&
1417          "size mismatch between args and parms!");
1418 
1419   for (size_t i = 0; i < TemplateArgs.size(); ++i) {
1420     const TemplateArgument &TA = TemplateArgs[i];
1421 
1422     // Separate consecutive packs by $$Z.
1423     if (i > 0 && TA.getKind() == TemplateArgument::Pack &&
1424         TemplateArgs[i - 1].getKind() == TemplateArgument::Pack)
1425       Out << "$$Z";
1426 
1427     mangleTemplateArg(TD, TA, TPL->getParam(i));
1428   }
1429 }
1430 
1431 void MicrosoftCXXNameMangler::mangleTemplateArg(const TemplateDecl *TD,
1432                                                 const TemplateArgument &TA,
1433                                                 const NamedDecl *Parm) {
1434   // <template-arg> ::= <type>
1435   //                ::= <integer-literal>
1436   //                ::= <member-data-pointer>
1437   //                ::= <member-function-pointer>
1438   //                ::= $E? <name> <type-encoding>
1439   //                ::= $1? <name> <type-encoding>
1440   //                ::= $0A@
1441   //                ::= <template-args>
1442 
1443   switch (TA.getKind()) {
1444   case TemplateArgument::Null:
1445     llvm_unreachable("Can't mangle null template arguments!");
1446   case TemplateArgument::TemplateExpansion:
1447     llvm_unreachable("Can't mangle template expansion arguments!");
1448   case TemplateArgument::Type: {
1449     QualType T = TA.getAsType();
1450     mangleType(T, SourceRange(), QMM_Escape);
1451     break;
1452   }
1453   case TemplateArgument::Declaration: {
1454     const NamedDecl *ND = TA.getAsDecl();
1455     if (isa<FieldDecl>(ND) || isa<IndirectFieldDecl>(ND)) {
1456       mangleMemberDataPointer(cast<CXXRecordDecl>(ND->getDeclContext())
1457                                   ->getMostRecentNonInjectedDecl(),
1458                               cast<ValueDecl>(ND));
1459     } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
1460       const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
1461       if (MD && MD->isInstance()) {
1462         mangleMemberFunctionPointer(
1463             MD->getParent()->getMostRecentNonInjectedDecl(), MD);
1464       } else {
1465         Out << "$1?";
1466         mangleName(FD);
1467         mangleFunctionEncoding(FD, /*ShouldMangle=*/true);
1468       }
1469     } else {
1470       mangle(ND, TA.getParamTypeForDecl()->isReferenceType() ? "$E?" : "$1?");
1471     }
1472     break;
1473   }
1474   case TemplateArgument::Integral:
1475     mangleIntegerLiteral(TA.getAsIntegral(),
1476                          TA.getIntegralType()->isBooleanType());
1477     break;
1478   case TemplateArgument::NullPtr: {
1479     QualType T = TA.getNullPtrType();
1480     if (const MemberPointerType *MPT = T->getAs<MemberPointerType>()) {
1481       const CXXRecordDecl *RD = MPT->getMostRecentCXXRecordDecl();
1482       if (MPT->isMemberFunctionPointerType() &&
1483           !isa<FunctionTemplateDecl>(TD)) {
1484         mangleMemberFunctionPointer(RD, nullptr);
1485         return;
1486       }
1487       if (MPT->isMemberDataPointer()) {
1488         if (!isa<FunctionTemplateDecl>(TD)) {
1489           mangleMemberDataPointer(RD, nullptr);
1490           return;
1491         }
1492         // nullptr data pointers are always represented with a single field
1493         // which is initialized with either 0 or -1.  Why -1?  Well, we need to
1494         // distinguish the case where the data member is at offset zero in the
1495         // record.
1496         // However, we are free to use 0 *if* we would use multiple fields for
1497         // non-nullptr member pointers.
1498         if (!RD->nullFieldOffsetIsZero()) {
1499           mangleIntegerLiteral(llvm::APSInt::get(-1), /*IsBoolean=*/false);
1500           return;
1501         }
1502       }
1503     }
1504     mangleIntegerLiteral(llvm::APSInt::getUnsigned(0), /*IsBoolean=*/false);
1505     break;
1506   }
1507   case TemplateArgument::Expression:
1508     mangleExpression(TA.getAsExpr());
1509     break;
1510   case TemplateArgument::Pack: {
1511     ArrayRef<TemplateArgument> TemplateArgs = TA.getPackAsArray();
1512     if (TemplateArgs.empty()) {
1513       if (isa<TemplateTypeParmDecl>(Parm) ||
1514           isa<TemplateTemplateParmDecl>(Parm))
1515         // MSVC 2015 changed the mangling for empty expanded template packs,
1516         // use the old mangling for link compatibility for old versions.
1517         Out << (Context.getASTContext().getLangOpts().isCompatibleWithMSVC(
1518                     LangOptions::MSVC2015)
1519                     ? "$$V"
1520                     : "$$$V");
1521       else if (isa<NonTypeTemplateParmDecl>(Parm))
1522         Out << "$S";
1523       else
1524         llvm_unreachable("unexpected template parameter decl!");
1525     } else {
1526       for (const TemplateArgument &PA : TemplateArgs)
1527         mangleTemplateArg(TD, PA, Parm);
1528     }
1529     break;
1530   }
1531   case TemplateArgument::Template: {
1532     const NamedDecl *ND =
1533         TA.getAsTemplate().getAsTemplateDecl()->getTemplatedDecl();
1534     if (const auto *TD = dyn_cast<TagDecl>(ND)) {
1535       mangleType(TD);
1536     } else if (isa<TypeAliasDecl>(ND)) {
1537       Out << "$$Y";
1538       mangleName(ND);
1539     } else {
1540       llvm_unreachable("unexpected template template NamedDecl!");
1541     }
1542     break;
1543   }
1544   }
1545 }
1546 
1547 void MicrosoftCXXNameMangler::mangleObjCProtocol(const ObjCProtocolDecl *PD) {
1548   llvm::SmallString<64> TemplateMangling;
1549   llvm::raw_svector_ostream Stream(TemplateMangling);
1550   MicrosoftCXXNameMangler Extra(Context, Stream);
1551 
1552   Stream << "?$";
1553   Extra.mangleSourceName("Protocol");
1554   Extra.mangleArtificialTagType(TTK_Struct, PD->getName());
1555 
1556   mangleArtificialTagType(TTK_Struct, TemplateMangling, {"__ObjC"});
1557 }
1558 
1559 void MicrosoftCXXNameMangler::mangleObjCLifetime(const QualType Type,
1560                                                  Qualifiers Quals,
1561                                                  SourceRange Range) {
1562   llvm::SmallString<64> TemplateMangling;
1563   llvm::raw_svector_ostream Stream(TemplateMangling);
1564   MicrosoftCXXNameMangler Extra(Context, Stream);
1565 
1566   Stream << "?$";
1567   switch (Quals.getObjCLifetime()) {
1568   case Qualifiers::OCL_None:
1569   case Qualifiers::OCL_ExplicitNone:
1570     break;
1571   case Qualifiers::OCL_Autoreleasing:
1572     Extra.mangleSourceName("Autoreleasing");
1573     break;
1574   case Qualifiers::OCL_Strong:
1575     Extra.mangleSourceName("Strong");
1576     break;
1577   case Qualifiers::OCL_Weak:
1578     Extra.mangleSourceName("Weak");
1579     break;
1580   }
1581   Extra.manglePointerCVQualifiers(Quals);
1582   Extra.manglePointerExtQualifiers(Quals, Type);
1583   Extra.mangleType(Type, Range);
1584 
1585   mangleArtificialTagType(TTK_Struct, TemplateMangling, {"__ObjC"});
1586 }
1587 
1588 void MicrosoftCXXNameMangler::mangleObjCKindOfType(const ObjCObjectType *T,
1589                                                    Qualifiers Quals,
1590                                                    SourceRange Range) {
1591   llvm::SmallString<64> TemplateMangling;
1592   llvm::raw_svector_ostream Stream(TemplateMangling);
1593   MicrosoftCXXNameMangler Extra(Context, Stream);
1594 
1595   Stream << "?$";
1596   Extra.mangleSourceName("KindOf");
1597   Extra.mangleType(QualType(T, 0)
1598                        .stripObjCKindOfType(getASTContext())
1599                        ->getAs<ObjCObjectType>(),
1600                    Quals, Range);
1601 
1602   mangleArtificialTagType(TTK_Struct, TemplateMangling, {"__ObjC"});
1603 }
1604 
1605 void MicrosoftCXXNameMangler::mangleQualifiers(Qualifiers Quals,
1606                                                bool IsMember) {
1607   // <cvr-qualifiers> ::= [E] [F] [I] <base-cvr-qualifiers>
1608   // 'E' means __ptr64 (32-bit only); 'F' means __unaligned (32/64-bit only);
1609   // 'I' means __restrict (32/64-bit).
1610   // Note that the MSVC __restrict keyword isn't the same as the C99 restrict
1611   // keyword!
1612   // <base-cvr-qualifiers> ::= A  # near
1613   //                       ::= B  # near const
1614   //                       ::= C  # near volatile
1615   //                       ::= D  # near const volatile
1616   //                       ::= E  # far (16-bit)
1617   //                       ::= F  # far const (16-bit)
1618   //                       ::= G  # far volatile (16-bit)
1619   //                       ::= H  # far const volatile (16-bit)
1620   //                       ::= I  # huge (16-bit)
1621   //                       ::= J  # huge const (16-bit)
1622   //                       ::= K  # huge volatile (16-bit)
1623   //                       ::= L  # huge const volatile (16-bit)
1624   //                       ::= M <basis> # based
1625   //                       ::= N <basis> # based const
1626   //                       ::= O <basis> # based volatile
1627   //                       ::= P <basis> # based const volatile
1628   //                       ::= Q  # near member
1629   //                       ::= R  # near const member
1630   //                       ::= S  # near volatile member
1631   //                       ::= T  # near const volatile member
1632   //                       ::= U  # far member (16-bit)
1633   //                       ::= V  # far const member (16-bit)
1634   //                       ::= W  # far volatile member (16-bit)
1635   //                       ::= X  # far const volatile member (16-bit)
1636   //                       ::= Y  # huge member (16-bit)
1637   //                       ::= Z  # huge const member (16-bit)
1638   //                       ::= 0  # huge volatile member (16-bit)
1639   //                       ::= 1  # huge const volatile member (16-bit)
1640   //                       ::= 2 <basis> # based member
1641   //                       ::= 3 <basis> # based const member
1642   //                       ::= 4 <basis> # based volatile member
1643   //                       ::= 5 <basis> # based const volatile member
1644   //                       ::= 6  # near function (pointers only)
1645   //                       ::= 7  # far function (pointers only)
1646   //                       ::= 8  # near method (pointers only)
1647   //                       ::= 9  # far method (pointers only)
1648   //                       ::= _A <basis> # based function (pointers only)
1649   //                       ::= _B <basis> # based function (far?) (pointers only)
1650   //                       ::= _C <basis> # based method (pointers only)
1651   //                       ::= _D <basis> # based method (far?) (pointers only)
1652   //                       ::= _E # block (Clang)
1653   // <basis> ::= 0 # __based(void)
1654   //         ::= 1 # __based(segment)?
1655   //         ::= 2 <name> # __based(name)
1656   //         ::= 3 # ?
1657   //         ::= 4 # ?
1658   //         ::= 5 # not really based
1659   bool HasConst = Quals.hasConst(),
1660        HasVolatile = Quals.hasVolatile();
1661 
1662   if (!IsMember) {
1663     if (HasConst && HasVolatile) {
1664       Out << 'D';
1665     } else if (HasVolatile) {
1666       Out << 'C';
1667     } else if (HasConst) {
1668       Out << 'B';
1669     } else {
1670       Out << 'A';
1671     }
1672   } else {
1673     if (HasConst && HasVolatile) {
1674       Out << 'T';
1675     } else if (HasVolatile) {
1676       Out << 'S';
1677     } else if (HasConst) {
1678       Out << 'R';
1679     } else {
1680       Out << 'Q';
1681     }
1682   }
1683 
1684   // FIXME: For now, just drop all extension qualifiers on the floor.
1685 }
1686 
1687 void
1688 MicrosoftCXXNameMangler::mangleRefQualifier(RefQualifierKind RefQualifier) {
1689   // <ref-qualifier> ::= G                # lvalue reference
1690   //                 ::= H                # rvalue-reference
1691   switch (RefQualifier) {
1692   case RQ_None:
1693     break;
1694 
1695   case RQ_LValue:
1696     Out << 'G';
1697     break;
1698 
1699   case RQ_RValue:
1700     Out << 'H';
1701     break;
1702   }
1703 }
1704 
1705 void MicrosoftCXXNameMangler::manglePointerExtQualifiers(Qualifiers Quals,
1706                                                          QualType PointeeType) {
1707   if (PointersAre64Bit &&
1708       (PointeeType.isNull() || !PointeeType->isFunctionType()))
1709     Out << 'E';
1710 
1711   if (Quals.hasRestrict())
1712     Out << 'I';
1713 
1714   if (Quals.hasUnaligned() ||
1715       (!PointeeType.isNull() && PointeeType.getLocalQualifiers().hasUnaligned()))
1716     Out << 'F';
1717 }
1718 
1719 void MicrosoftCXXNameMangler::manglePointerCVQualifiers(Qualifiers Quals) {
1720   // <pointer-cv-qualifiers> ::= P  # no qualifiers
1721   //                         ::= Q  # const
1722   //                         ::= R  # volatile
1723   //                         ::= S  # const volatile
1724   bool HasConst = Quals.hasConst(),
1725        HasVolatile = Quals.hasVolatile();
1726 
1727   if (HasConst && HasVolatile) {
1728     Out << 'S';
1729   } else if (HasVolatile) {
1730     Out << 'R';
1731   } else if (HasConst) {
1732     Out << 'Q';
1733   } else {
1734     Out << 'P';
1735   }
1736 }
1737 
1738 void MicrosoftCXXNameMangler::mangleFunctionArgumentType(QualType T,
1739                                                          SourceRange Range) {
1740   // MSVC will backreference two canonically equivalent types that have slightly
1741   // different manglings when mangled alone.
1742 
1743   // Decayed types do not match up with non-decayed versions of the same type.
1744   //
1745   // e.g.
1746   // void (*x)(void) will not form a backreference with void x(void)
1747   void *TypePtr;
1748   if (const auto *DT = T->getAs<DecayedType>()) {
1749     QualType OriginalType = DT->getOriginalType();
1750     // All decayed ArrayTypes should be treated identically; as-if they were
1751     // a decayed IncompleteArrayType.
1752     if (const auto *AT = getASTContext().getAsArrayType(OriginalType))
1753       OriginalType = getASTContext().getIncompleteArrayType(
1754           AT->getElementType(), AT->getSizeModifier(),
1755           AT->getIndexTypeCVRQualifiers());
1756 
1757     TypePtr = OriginalType.getCanonicalType().getAsOpaquePtr();
1758     // If the original parameter was textually written as an array,
1759     // instead treat the decayed parameter like it's const.
1760     //
1761     // e.g.
1762     // int [] -> int * const
1763     if (OriginalType->isArrayType())
1764       T = T.withConst();
1765   } else {
1766     TypePtr = T.getCanonicalType().getAsOpaquePtr();
1767   }
1768 
1769   ArgBackRefMap::iterator Found = FunArgBackReferences.find(TypePtr);
1770 
1771   if (Found == FunArgBackReferences.end()) {
1772     size_t OutSizeBefore = Out.tell();
1773 
1774     mangleType(T, Range, QMM_Drop);
1775 
1776     // See if it's worth creating a back reference.
1777     // Only types longer than 1 character are considered
1778     // and only 10 back references slots are available:
1779     bool LongerThanOneChar = (Out.tell() - OutSizeBefore > 1);
1780     if (LongerThanOneChar && FunArgBackReferences.size() < 10) {
1781       size_t Size = FunArgBackReferences.size();
1782       FunArgBackReferences[TypePtr] = Size;
1783     }
1784   } else {
1785     Out << Found->second;
1786   }
1787 }
1788 
1789 void MicrosoftCXXNameMangler::manglePassObjectSizeArg(
1790     const PassObjectSizeAttr *POSA) {
1791   int Type = POSA->getType();
1792   bool Dynamic = POSA->isDynamic();
1793 
1794   auto Iter = PassObjectSizeArgs.insert({Type, Dynamic}).first;
1795   auto *TypePtr = (const void *)&*Iter;
1796   ArgBackRefMap::iterator Found = FunArgBackReferences.find(TypePtr);
1797 
1798   if (Found == FunArgBackReferences.end()) {
1799     std::string Name =
1800         Dynamic ? "__pass_dynamic_object_size" : "__pass_object_size";
1801     mangleArtificialTagType(TTK_Enum, Name + llvm::utostr(Type), {"__clang"});
1802 
1803     if (FunArgBackReferences.size() < 10) {
1804       size_t Size = FunArgBackReferences.size();
1805       FunArgBackReferences[TypePtr] = Size;
1806     }
1807   } else {
1808     Out << Found->second;
1809   }
1810 }
1811 
1812 void MicrosoftCXXNameMangler::mangleAddressSpaceType(QualType T,
1813                                                      Qualifiers Quals,
1814                                                      SourceRange Range) {
1815   // Address space is mangled as an unqualified templated type in the __clang
1816   // namespace. The demangled version of this is:
1817   // In the case of a language specific address space:
1818   // __clang::struct _AS[language_addr_space]<Type>
1819   // where:
1820   //  <language_addr_space> ::= <OpenCL-addrspace> | <CUDA-addrspace>
1821   //    <OpenCL-addrspace> ::= "CL" [ "global" | "local" | "constant" |
1822   //                                "private"| "generic" ]
1823   //    <CUDA-addrspace> ::= "CU" [ "device" | "constant" | "shared" ]
1824   //    Note that the above were chosen to match the Itanium mangling for this.
1825   //
1826   // In the case of a non-language specific address space:
1827   //  __clang::struct _AS<TargetAS, Type>
1828   assert(Quals.hasAddressSpace() && "Not valid without address space");
1829   llvm::SmallString<32> ASMangling;
1830   llvm::raw_svector_ostream Stream(ASMangling);
1831   MicrosoftCXXNameMangler Extra(Context, Stream);
1832   Stream << "?$";
1833 
1834   LangAS AS = Quals.getAddressSpace();
1835   if (Context.getASTContext().addressSpaceMapManglingFor(AS)) {
1836     unsigned TargetAS = Context.getASTContext().getTargetAddressSpace(AS);
1837     Extra.mangleSourceName("_AS");
1838     Extra.mangleIntegerLiteral(llvm::APSInt::getUnsigned(TargetAS),
1839                                /*IsBoolean*/ false);
1840   } else {
1841     switch (AS) {
1842     default:
1843       llvm_unreachable("Not a language specific address space");
1844     case LangAS::opencl_global:
1845       Extra.mangleSourceName("_ASCLglobal");
1846       break;
1847     case LangAS::opencl_local:
1848       Extra.mangleSourceName("_ASCLlocal");
1849       break;
1850     case LangAS::opencl_constant:
1851       Extra.mangleSourceName("_ASCLconstant");
1852       break;
1853     case LangAS::opencl_private:
1854       Extra.mangleSourceName("_ASCLprivate");
1855       break;
1856     case LangAS::opencl_generic:
1857       Extra.mangleSourceName("_ASCLgeneric");
1858       break;
1859     case LangAS::cuda_device:
1860       Extra.mangleSourceName("_ASCUdevice");
1861       break;
1862     case LangAS::cuda_constant:
1863       Extra.mangleSourceName("_ASCUconstant");
1864       break;
1865     case LangAS::cuda_shared:
1866       Extra.mangleSourceName("_ASCUshared");
1867       break;
1868     }
1869   }
1870 
1871   Extra.mangleType(T, Range, QMM_Escape);
1872   mangleQualifiers(Qualifiers(), false);
1873   mangleArtificialTagType(TTK_Struct, ASMangling, {"__clang"});
1874 }
1875 
1876 void MicrosoftCXXNameMangler::mangleType(QualType T, SourceRange Range,
1877                                          QualifierMangleMode QMM) {
1878   // Don't use the canonical types.  MSVC includes things like 'const' on
1879   // pointer arguments to function pointers that canonicalization strips away.
1880   T = T.getDesugaredType(getASTContext());
1881   Qualifiers Quals = T.getLocalQualifiers();
1882 
1883   if (const ArrayType *AT = getASTContext().getAsArrayType(T)) {
1884     // If there were any Quals, getAsArrayType() pushed them onto the array
1885     // element type.
1886     if (QMM == QMM_Mangle)
1887       Out << 'A';
1888     else if (QMM == QMM_Escape || QMM == QMM_Result)
1889       Out << "$$B";
1890     mangleArrayType(AT);
1891     return;
1892   }
1893 
1894   bool IsPointer = T->isAnyPointerType() || T->isMemberPointerType() ||
1895                    T->isReferenceType() || T->isBlockPointerType();
1896 
1897   switch (QMM) {
1898   case QMM_Drop:
1899     if (Quals.hasObjCLifetime())
1900       Quals = Quals.withoutObjCLifetime();
1901     break;
1902   case QMM_Mangle:
1903     if (const FunctionType *FT = dyn_cast<FunctionType>(T)) {
1904       Out << '6';
1905       mangleFunctionType(FT);
1906       return;
1907     }
1908     mangleQualifiers(Quals, false);
1909     break;
1910   case QMM_Escape:
1911     if (!IsPointer && Quals) {
1912       Out << "$$C";
1913       mangleQualifiers(Quals, false);
1914     }
1915     break;
1916   case QMM_Result:
1917     // Presence of __unaligned qualifier shouldn't affect mangling here.
1918     Quals.removeUnaligned();
1919     if (Quals.hasObjCLifetime())
1920       Quals = Quals.withoutObjCLifetime();
1921     if ((!IsPointer && Quals) || isa<TagType>(T) || isArtificialTagType(T)) {
1922       Out << '?';
1923       mangleQualifiers(Quals, false);
1924     }
1925     break;
1926   }
1927 
1928   const Type *ty = T.getTypePtr();
1929 
1930   switch (ty->getTypeClass()) {
1931 #define ABSTRACT_TYPE(CLASS, PARENT)
1932 #define NON_CANONICAL_TYPE(CLASS, PARENT) \
1933   case Type::CLASS: \
1934     llvm_unreachable("can't mangle non-canonical type " #CLASS "Type"); \
1935     return;
1936 #define TYPE(CLASS, PARENT) \
1937   case Type::CLASS: \
1938     mangleType(cast<CLASS##Type>(ty), Quals, Range); \
1939     break;
1940 #include "clang/AST/TypeNodes.def"
1941 #undef ABSTRACT_TYPE
1942 #undef NON_CANONICAL_TYPE
1943 #undef TYPE
1944   }
1945 }
1946 
1947 void MicrosoftCXXNameMangler::mangleType(const BuiltinType *T, Qualifiers,
1948                                          SourceRange Range) {
1949   //  <type>         ::= <builtin-type>
1950   //  <builtin-type> ::= X  # void
1951   //                 ::= C  # signed char
1952   //                 ::= D  # char
1953   //                 ::= E  # unsigned char
1954   //                 ::= F  # short
1955   //                 ::= G  # unsigned short (or wchar_t if it's not a builtin)
1956   //                 ::= H  # int
1957   //                 ::= I  # unsigned int
1958   //                 ::= J  # long
1959   //                 ::= K  # unsigned long
1960   //                     L  # <none>
1961   //                 ::= M  # float
1962   //                 ::= N  # double
1963   //                 ::= O  # long double (__float80 is mangled differently)
1964   //                 ::= _J # long long, __int64
1965   //                 ::= _K # unsigned long long, __int64
1966   //                 ::= _L # __int128
1967   //                 ::= _M # unsigned __int128
1968   //                 ::= _N # bool
1969   //                     _O # <array in parameter>
1970   //                 ::= _Q # char8_t
1971   //                 ::= _S # char16_t
1972   //                 ::= _T # __float80 (Intel)
1973   //                 ::= _U # char32_t
1974   //                 ::= _W # wchar_t
1975   //                 ::= _Z # __float80 (Digital Mars)
1976   switch (T->getKind()) {
1977   case BuiltinType::Void:
1978     Out << 'X';
1979     break;
1980   case BuiltinType::SChar:
1981     Out << 'C';
1982     break;
1983   case BuiltinType::Char_U:
1984   case BuiltinType::Char_S:
1985     Out << 'D';
1986     break;
1987   case BuiltinType::UChar:
1988     Out << 'E';
1989     break;
1990   case BuiltinType::Short:
1991     Out << 'F';
1992     break;
1993   case BuiltinType::UShort:
1994     Out << 'G';
1995     break;
1996   case BuiltinType::Int:
1997     Out << 'H';
1998     break;
1999   case BuiltinType::UInt:
2000     Out << 'I';
2001     break;
2002   case BuiltinType::Long:
2003     Out << 'J';
2004     break;
2005   case BuiltinType::ULong:
2006     Out << 'K';
2007     break;
2008   case BuiltinType::Float:
2009     Out << 'M';
2010     break;
2011   case BuiltinType::Double:
2012     Out << 'N';
2013     break;
2014   // TODO: Determine size and mangle accordingly
2015   case BuiltinType::LongDouble:
2016     Out << 'O';
2017     break;
2018   case BuiltinType::LongLong:
2019     Out << "_J";
2020     break;
2021   case BuiltinType::ULongLong:
2022     Out << "_K";
2023     break;
2024   case BuiltinType::Int128:
2025     Out << "_L";
2026     break;
2027   case BuiltinType::UInt128:
2028     Out << "_M";
2029     break;
2030   case BuiltinType::Bool:
2031     Out << "_N";
2032     break;
2033   case BuiltinType::Char8:
2034     Out << "_Q";
2035     break;
2036   case BuiltinType::Char16:
2037     Out << "_S";
2038     break;
2039   case BuiltinType::Char32:
2040     Out << "_U";
2041     break;
2042   case BuiltinType::WChar_S:
2043   case BuiltinType::WChar_U:
2044     Out << "_W";
2045     break;
2046 
2047 #define BUILTIN_TYPE(Id, SingletonId)
2048 #define PLACEHOLDER_TYPE(Id, SingletonId) \
2049   case BuiltinType::Id:
2050 #include "clang/AST/BuiltinTypes.def"
2051   case BuiltinType::Dependent:
2052     llvm_unreachable("placeholder types shouldn't get to name mangling");
2053 
2054   case BuiltinType::ObjCId:
2055     mangleArtificialTagType(TTK_Struct, "objc_object");
2056     break;
2057   case BuiltinType::ObjCClass:
2058     mangleArtificialTagType(TTK_Struct, "objc_class");
2059     break;
2060   case BuiltinType::ObjCSel:
2061     mangleArtificialTagType(TTK_Struct, "objc_selector");
2062     break;
2063 
2064 #define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
2065   case BuiltinType::Id: \
2066     Out << "PAUocl_" #ImgType "_" #Suffix "@@"; \
2067     break;
2068 #include "clang/Basic/OpenCLImageTypes.def"
2069   case BuiltinType::OCLSampler:
2070     Out << "PA";
2071     mangleArtificialTagType(TTK_Struct, "ocl_sampler");
2072     break;
2073   case BuiltinType::OCLEvent:
2074     Out << "PA";
2075     mangleArtificialTagType(TTK_Struct, "ocl_event");
2076     break;
2077   case BuiltinType::OCLClkEvent:
2078     Out << "PA";
2079     mangleArtificialTagType(TTK_Struct, "ocl_clkevent");
2080     break;
2081   case BuiltinType::OCLQueue:
2082     Out << "PA";
2083     mangleArtificialTagType(TTK_Struct, "ocl_queue");
2084     break;
2085   case BuiltinType::OCLReserveID:
2086     Out << "PA";
2087     mangleArtificialTagType(TTK_Struct, "ocl_reserveid");
2088     break;
2089 #define EXT_OPAQUE_TYPE(ExtType, Id, Ext) \
2090   case BuiltinType::Id: \
2091     mangleArtificialTagType(TTK_Struct, "ocl_" #ExtType); \
2092     break;
2093 #include "clang/Basic/OpenCLExtensionTypes.def"
2094 
2095   case BuiltinType::NullPtr:
2096     Out << "$$T";
2097     break;
2098 
2099   case BuiltinType::Float16:
2100     mangleArtificialTagType(TTK_Struct, "_Float16", {"__clang"});
2101     break;
2102 
2103   case BuiltinType::Half:
2104     mangleArtificialTagType(TTK_Struct, "_Half", {"__clang"});
2105     break;
2106 
2107 #define SVE_TYPE(Name, Id, SingletonId) \
2108   case BuiltinType::Id:
2109 #include "clang/Basic/AArch64SVEACLETypes.def"
2110   case BuiltinType::ShortAccum:
2111   case BuiltinType::Accum:
2112   case BuiltinType::LongAccum:
2113   case BuiltinType::UShortAccum:
2114   case BuiltinType::UAccum:
2115   case BuiltinType::ULongAccum:
2116   case BuiltinType::ShortFract:
2117   case BuiltinType::Fract:
2118   case BuiltinType::LongFract:
2119   case BuiltinType::UShortFract:
2120   case BuiltinType::UFract:
2121   case BuiltinType::ULongFract:
2122   case BuiltinType::SatShortAccum:
2123   case BuiltinType::SatAccum:
2124   case BuiltinType::SatLongAccum:
2125   case BuiltinType::SatUShortAccum:
2126   case BuiltinType::SatUAccum:
2127   case BuiltinType::SatULongAccum:
2128   case BuiltinType::SatShortFract:
2129   case BuiltinType::SatFract:
2130   case BuiltinType::SatLongFract:
2131   case BuiltinType::SatUShortFract:
2132   case BuiltinType::SatUFract:
2133   case BuiltinType::SatULongFract:
2134   case BuiltinType::Float128: {
2135     DiagnosticsEngine &Diags = Context.getDiags();
2136     unsigned DiagID = Diags.getCustomDiagID(
2137         DiagnosticsEngine::Error, "cannot mangle this built-in %0 type yet");
2138     Diags.Report(Range.getBegin(), DiagID)
2139         << T->getName(Context.getASTContext().getPrintingPolicy()) << Range;
2140     break;
2141   }
2142   }
2143 }
2144 
2145 // <type>          ::= <function-type>
2146 void MicrosoftCXXNameMangler::mangleType(const FunctionProtoType *T, Qualifiers,
2147                                          SourceRange) {
2148   // Structors only appear in decls, so at this point we know it's not a
2149   // structor type.
2150   // FIXME: This may not be lambda-friendly.
2151   if (T->getMethodQuals() || T->getRefQualifier() != RQ_None) {
2152     Out << "$$A8@@";
2153     mangleFunctionType(T, /*D=*/nullptr, /*ForceThisQuals=*/true);
2154   } else {
2155     Out << "$$A6";
2156     mangleFunctionType(T);
2157   }
2158 }
2159 void MicrosoftCXXNameMangler::mangleType(const FunctionNoProtoType *T,
2160                                          Qualifiers, SourceRange) {
2161   Out << "$$A6";
2162   mangleFunctionType(T);
2163 }
2164 
2165 void MicrosoftCXXNameMangler::mangleFunctionType(const FunctionType *T,
2166                                                  const FunctionDecl *D,
2167                                                  bool ForceThisQuals,
2168                                                  bool MangleExceptionSpec) {
2169   // <function-type> ::= <this-cvr-qualifiers> <calling-convention>
2170   //                     <return-type> <argument-list> <throw-spec>
2171   const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(T);
2172 
2173   SourceRange Range;
2174   if (D) Range = D->getSourceRange();
2175 
2176   bool IsInLambda = false;
2177   bool IsStructor = false, HasThisQuals = ForceThisQuals, IsCtorClosure = false;
2178   CallingConv CC = T->getCallConv();
2179   if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(D)) {
2180     if (MD->getParent()->isLambda())
2181       IsInLambda = true;
2182     if (MD->isInstance())
2183       HasThisQuals = true;
2184     if (isa<CXXDestructorDecl>(MD)) {
2185       IsStructor = true;
2186     } else if (isa<CXXConstructorDecl>(MD)) {
2187       IsStructor = true;
2188       IsCtorClosure = (StructorType == Ctor_CopyingClosure ||
2189                        StructorType == Ctor_DefaultClosure) &&
2190                       isStructorDecl(MD);
2191       if (IsCtorClosure)
2192         CC = getASTContext().getDefaultCallingConvention(
2193             /*IsVariadic=*/false, /*IsCXXMethod=*/true);
2194     }
2195   }
2196 
2197   // If this is a C++ instance method, mangle the CVR qualifiers for the
2198   // this pointer.
2199   if (HasThisQuals) {
2200     Qualifiers Quals = Proto->getMethodQuals();
2201     manglePointerExtQualifiers(Quals, /*PointeeType=*/QualType());
2202     mangleRefQualifier(Proto->getRefQualifier());
2203     mangleQualifiers(Quals, /*IsMember=*/false);
2204   }
2205 
2206   mangleCallingConvention(CC);
2207 
2208   // <return-type> ::= <type>
2209   //               ::= @ # structors (they have no declared return type)
2210   if (IsStructor) {
2211     if (isa<CXXDestructorDecl>(D) && isStructorDecl(D)) {
2212       // The scalar deleting destructor takes an extra int argument which is not
2213       // reflected in the AST.
2214       if (StructorType == Dtor_Deleting) {
2215         Out << (PointersAre64Bit ? "PEAXI@Z" : "PAXI@Z");
2216         return;
2217       }
2218       // The vbase destructor returns void which is not reflected in the AST.
2219       if (StructorType == Dtor_Complete) {
2220         Out << "XXZ";
2221         return;
2222       }
2223     }
2224     if (IsCtorClosure) {
2225       // Default constructor closure and copy constructor closure both return
2226       // void.
2227       Out << 'X';
2228 
2229       if (StructorType == Ctor_DefaultClosure) {
2230         // Default constructor closure always has no arguments.
2231         Out << 'X';
2232       } else if (StructorType == Ctor_CopyingClosure) {
2233         // Copy constructor closure always takes an unqualified reference.
2234         mangleFunctionArgumentType(getASTContext().getLValueReferenceType(
2235                                        Proto->getParamType(0)
2236                                            ->getAs<LValueReferenceType>()
2237                                            ->getPointeeType(),
2238                                        /*SpelledAsLValue=*/true),
2239                                    Range);
2240         Out << '@';
2241       } else {
2242         llvm_unreachable("unexpected constructor closure!");
2243       }
2244       Out << 'Z';
2245       return;
2246     }
2247     Out << '@';
2248   } else {
2249     QualType ResultType = T->getReturnType();
2250     if (const auto *AT =
2251             dyn_cast_or_null<AutoType>(ResultType->getContainedAutoType())) {
2252       Out << '?';
2253       mangleQualifiers(ResultType.getLocalQualifiers(), /*IsMember=*/false);
2254       Out << '?';
2255       assert(AT->getKeyword() != AutoTypeKeyword::GNUAutoType &&
2256              "shouldn't need to mangle __auto_type!");
2257       mangleSourceName(AT->isDecltypeAuto() ? "<decltype-auto>" : "<auto>");
2258       Out << '@';
2259     } else if (IsInLambda) {
2260       Out << '@';
2261     } else {
2262       if (ResultType->isVoidType())
2263         ResultType = ResultType.getUnqualifiedType();
2264       mangleType(ResultType, Range, QMM_Result);
2265     }
2266   }
2267 
2268   // <argument-list> ::= X # void
2269   //                 ::= <type>+ @
2270   //                 ::= <type>* Z # varargs
2271   if (!Proto) {
2272     // Function types without prototypes can arise when mangling a function type
2273     // within an overloadable function in C. We mangle these as the absence of
2274     // any parameter types (not even an empty parameter list).
2275     Out << '@';
2276   } else if (Proto->getNumParams() == 0 && !Proto->isVariadic()) {
2277     Out << 'X';
2278   } else {
2279     // Happens for function pointer type arguments for example.
2280     for (unsigned I = 0, E = Proto->getNumParams(); I != E; ++I) {
2281       mangleFunctionArgumentType(Proto->getParamType(I), Range);
2282       // Mangle each pass_object_size parameter as if it's a parameter of enum
2283       // type passed directly after the parameter with the pass_object_size
2284       // attribute. The aforementioned enum's name is __pass_object_size, and we
2285       // pretend it resides in a top-level namespace called __clang.
2286       //
2287       // FIXME: Is there a defined extension notation for the MS ABI, or is it
2288       // necessary to just cross our fingers and hope this type+namespace
2289       // combination doesn't conflict with anything?
2290       if (D)
2291         if (const auto *P = D->getParamDecl(I)->getAttr<PassObjectSizeAttr>())
2292           manglePassObjectSizeArg(P);
2293     }
2294     // <builtin-type>      ::= Z  # ellipsis
2295     if (Proto->isVariadic())
2296       Out << 'Z';
2297     else
2298       Out << '@';
2299   }
2300 
2301   if (MangleExceptionSpec && getASTContext().getLangOpts().CPlusPlus17 &&
2302       getASTContext().getLangOpts().isCompatibleWithMSVC(
2303           LangOptions::MSVC2017_5))
2304     mangleThrowSpecification(Proto);
2305   else
2306     Out << 'Z';
2307 }
2308 
2309 void MicrosoftCXXNameMangler::mangleFunctionClass(const FunctionDecl *FD) {
2310   // <function-class>  ::= <member-function> E? # E designates a 64-bit 'this'
2311   //                                            # pointer. in 64-bit mode *all*
2312   //                                            # 'this' pointers are 64-bit.
2313   //                   ::= <global-function>
2314   // <member-function> ::= A # private: near
2315   //                   ::= B # private: far
2316   //                   ::= C # private: static near
2317   //                   ::= D # private: static far
2318   //                   ::= E # private: virtual near
2319   //                   ::= F # private: virtual far
2320   //                   ::= I # protected: near
2321   //                   ::= J # protected: far
2322   //                   ::= K # protected: static near
2323   //                   ::= L # protected: static far
2324   //                   ::= M # protected: virtual near
2325   //                   ::= N # protected: virtual far
2326   //                   ::= Q # public: near
2327   //                   ::= R # public: far
2328   //                   ::= S # public: static near
2329   //                   ::= T # public: static far
2330   //                   ::= U # public: virtual near
2331   //                   ::= V # public: virtual far
2332   // <global-function> ::= Y # global near
2333   //                   ::= Z # global far
2334   if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
2335     bool IsVirtual = MD->isVirtual();
2336     // When mangling vbase destructor variants, ignore whether or not the
2337     // underlying destructor was defined to be virtual.
2338     if (isa<CXXDestructorDecl>(MD) && isStructorDecl(MD) &&
2339         StructorType == Dtor_Complete) {
2340       IsVirtual = false;
2341     }
2342     switch (MD->getAccess()) {
2343       case AS_none:
2344         llvm_unreachable("Unsupported access specifier");
2345       case AS_private:
2346         if (MD->isStatic())
2347           Out << 'C';
2348         else if (IsVirtual)
2349           Out << 'E';
2350         else
2351           Out << 'A';
2352         break;
2353       case AS_protected:
2354         if (MD->isStatic())
2355           Out << 'K';
2356         else if (IsVirtual)
2357           Out << 'M';
2358         else
2359           Out << 'I';
2360         break;
2361       case AS_public:
2362         if (MD->isStatic())
2363           Out << 'S';
2364         else if (IsVirtual)
2365           Out << 'U';
2366         else
2367           Out << 'Q';
2368     }
2369   } else {
2370     Out << 'Y';
2371   }
2372 }
2373 void MicrosoftCXXNameMangler::mangleCallingConvention(CallingConv CC) {
2374   // <calling-convention> ::= A # __cdecl
2375   //                      ::= B # __export __cdecl
2376   //                      ::= C # __pascal
2377   //                      ::= D # __export __pascal
2378   //                      ::= E # __thiscall
2379   //                      ::= F # __export __thiscall
2380   //                      ::= G # __stdcall
2381   //                      ::= H # __export __stdcall
2382   //                      ::= I # __fastcall
2383   //                      ::= J # __export __fastcall
2384   //                      ::= Q # __vectorcall
2385   //                      ::= w # __regcall
2386   // The 'export' calling conventions are from a bygone era
2387   // (*cough*Win16*cough*) when functions were declared for export with
2388   // that keyword. (It didn't actually export them, it just made them so
2389   // that they could be in a DLL and somebody from another module could call
2390   // them.)
2391 
2392   switch (CC) {
2393     default:
2394       llvm_unreachable("Unsupported CC for mangling");
2395     case CC_Win64:
2396     case CC_X86_64SysV:
2397     case CC_C: Out << 'A'; break;
2398     case CC_X86Pascal: Out << 'C'; break;
2399     case CC_X86ThisCall: Out << 'E'; break;
2400     case CC_X86StdCall: Out << 'G'; break;
2401     case CC_X86FastCall: Out << 'I'; break;
2402     case CC_X86VectorCall: Out << 'Q'; break;
2403     case CC_Swift: Out << 'S'; break;
2404     case CC_PreserveMost: Out << 'U'; break;
2405     case CC_X86RegCall: Out << 'w'; break;
2406   }
2407 }
2408 void MicrosoftCXXNameMangler::mangleCallingConvention(const FunctionType *T) {
2409   mangleCallingConvention(T->getCallConv());
2410 }
2411 
2412 void MicrosoftCXXNameMangler::mangleThrowSpecification(
2413                                                 const FunctionProtoType *FT) {
2414   // <throw-spec> ::= Z # (default)
2415   //              ::= _E # noexcept
2416   if (FT->canThrow())
2417     Out << 'Z';
2418   else
2419     Out << "_E";
2420 }
2421 
2422 void MicrosoftCXXNameMangler::mangleType(const UnresolvedUsingType *T,
2423                                          Qualifiers, SourceRange Range) {
2424   // Probably should be mangled as a template instantiation; need to see what
2425   // VC does first.
2426   DiagnosticsEngine &Diags = Context.getDiags();
2427   unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
2428     "cannot mangle this unresolved dependent type yet");
2429   Diags.Report(Range.getBegin(), DiagID)
2430     << Range;
2431 }
2432 
2433 // <type>        ::= <union-type> | <struct-type> | <class-type> | <enum-type>
2434 // <union-type>  ::= T <name>
2435 // <struct-type> ::= U <name>
2436 // <class-type>  ::= V <name>
2437 // <enum-type>   ::= W4 <name>
2438 void MicrosoftCXXNameMangler::mangleTagTypeKind(TagTypeKind TTK) {
2439   switch (TTK) {
2440     case TTK_Union:
2441       Out << 'T';
2442       break;
2443     case TTK_Struct:
2444     case TTK_Interface:
2445       Out << 'U';
2446       break;
2447     case TTK_Class:
2448       Out << 'V';
2449       break;
2450     case TTK_Enum:
2451       Out << "W4";
2452       break;
2453   }
2454 }
2455 void MicrosoftCXXNameMangler::mangleType(const EnumType *T, Qualifiers,
2456                                          SourceRange) {
2457   mangleType(cast<TagType>(T)->getDecl());
2458 }
2459 void MicrosoftCXXNameMangler::mangleType(const RecordType *T, Qualifiers,
2460                                          SourceRange) {
2461   mangleType(cast<TagType>(T)->getDecl());
2462 }
2463 void MicrosoftCXXNameMangler::mangleType(const TagDecl *TD) {
2464   mangleTagTypeKind(TD->getTagKind());
2465   mangleName(TD);
2466 }
2467 
2468 // If you add a call to this, consider updating isArtificialTagType() too.
2469 void MicrosoftCXXNameMangler::mangleArtificialTagType(
2470     TagTypeKind TK, StringRef UnqualifiedName,
2471     ArrayRef<StringRef> NestedNames) {
2472   // <name> ::= <unscoped-name> {[<named-scope>]+ | [<nested-name>]}? @
2473   mangleTagTypeKind(TK);
2474 
2475   // Always start with the unqualified name.
2476   mangleSourceName(UnqualifiedName);
2477 
2478   for (auto I = NestedNames.rbegin(), E = NestedNames.rend(); I != E; ++I)
2479     mangleSourceName(*I);
2480 
2481   // Terminate the whole name with an '@'.
2482   Out << '@';
2483 }
2484 
2485 // <type>       ::= <array-type>
2486 // <array-type> ::= <pointer-cvr-qualifiers> <cvr-qualifiers>
2487 //                  [Y <dimension-count> <dimension>+]
2488 //                  <element-type> # as global, E is never required
2489 // It's supposed to be the other way around, but for some strange reason, it
2490 // isn't. Today this behavior is retained for the sole purpose of backwards
2491 // compatibility.
2492 void MicrosoftCXXNameMangler::mangleDecayedArrayType(const ArrayType *T) {
2493   // This isn't a recursive mangling, so now we have to do it all in this
2494   // one call.
2495   manglePointerCVQualifiers(T->getElementType().getQualifiers());
2496   mangleType(T->getElementType(), SourceRange());
2497 }
2498 void MicrosoftCXXNameMangler::mangleType(const ConstantArrayType *T, Qualifiers,
2499                                          SourceRange) {
2500   llvm_unreachable("Should have been special cased");
2501 }
2502 void MicrosoftCXXNameMangler::mangleType(const VariableArrayType *T, Qualifiers,
2503                                          SourceRange) {
2504   llvm_unreachable("Should have been special cased");
2505 }
2506 void MicrosoftCXXNameMangler::mangleType(const DependentSizedArrayType *T,
2507                                          Qualifiers, SourceRange) {
2508   llvm_unreachable("Should have been special cased");
2509 }
2510 void MicrosoftCXXNameMangler::mangleType(const IncompleteArrayType *T,
2511                                          Qualifiers, SourceRange) {
2512   llvm_unreachable("Should have been special cased");
2513 }
2514 void MicrosoftCXXNameMangler::mangleArrayType(const ArrayType *T) {
2515   QualType ElementTy(T, 0);
2516   SmallVector<llvm::APInt, 3> Dimensions;
2517   for (;;) {
2518     if (ElementTy->isConstantArrayType()) {
2519       const ConstantArrayType *CAT =
2520           getASTContext().getAsConstantArrayType(ElementTy);
2521       Dimensions.push_back(CAT->getSize());
2522       ElementTy = CAT->getElementType();
2523     } else if (ElementTy->isIncompleteArrayType()) {
2524       const IncompleteArrayType *IAT =
2525           getASTContext().getAsIncompleteArrayType(ElementTy);
2526       Dimensions.push_back(llvm::APInt(32, 0));
2527       ElementTy = IAT->getElementType();
2528     } else if (ElementTy->isVariableArrayType()) {
2529       const VariableArrayType *VAT =
2530         getASTContext().getAsVariableArrayType(ElementTy);
2531       Dimensions.push_back(llvm::APInt(32, 0));
2532       ElementTy = VAT->getElementType();
2533     } else if (ElementTy->isDependentSizedArrayType()) {
2534       // The dependent expression has to be folded into a constant (TODO).
2535       const DependentSizedArrayType *DSAT =
2536         getASTContext().getAsDependentSizedArrayType(ElementTy);
2537       DiagnosticsEngine &Diags = Context.getDiags();
2538       unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
2539         "cannot mangle this dependent-length array yet");
2540       Diags.Report(DSAT->getSizeExpr()->getExprLoc(), DiagID)
2541         << DSAT->getBracketsRange();
2542       return;
2543     } else {
2544       break;
2545     }
2546   }
2547   Out << 'Y';
2548   // <dimension-count> ::= <number> # number of extra dimensions
2549   mangleNumber(Dimensions.size());
2550   for (const llvm::APInt &Dimension : Dimensions)
2551     mangleNumber(Dimension.getLimitedValue());
2552   mangleType(ElementTy, SourceRange(), QMM_Escape);
2553 }
2554 
2555 // <type>                   ::= <pointer-to-member-type>
2556 // <pointer-to-member-type> ::= <pointer-cvr-qualifiers> <cvr-qualifiers>
2557 //                                                          <class name> <type>
2558 void MicrosoftCXXNameMangler::mangleType(const MemberPointerType *T,
2559                                          Qualifiers Quals, SourceRange Range) {
2560   QualType PointeeType = T->getPointeeType();
2561   manglePointerCVQualifiers(Quals);
2562   manglePointerExtQualifiers(Quals, PointeeType);
2563   if (const FunctionProtoType *FPT = PointeeType->getAs<FunctionProtoType>()) {
2564     Out << '8';
2565     mangleName(T->getClass()->castAs<RecordType>()->getDecl());
2566     mangleFunctionType(FPT, nullptr, true);
2567   } else {
2568     mangleQualifiers(PointeeType.getQualifiers(), true);
2569     mangleName(T->getClass()->castAs<RecordType>()->getDecl());
2570     mangleType(PointeeType, Range, QMM_Drop);
2571   }
2572 }
2573 
2574 void MicrosoftCXXNameMangler::mangleType(const TemplateTypeParmType *T,
2575                                          Qualifiers, SourceRange Range) {
2576   DiagnosticsEngine &Diags = Context.getDiags();
2577   unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
2578     "cannot mangle this template type parameter type yet");
2579   Diags.Report(Range.getBegin(), DiagID)
2580     << Range;
2581 }
2582 
2583 void MicrosoftCXXNameMangler::mangleType(const SubstTemplateTypeParmPackType *T,
2584                                          Qualifiers, SourceRange Range) {
2585   DiagnosticsEngine &Diags = Context.getDiags();
2586   unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
2587     "cannot mangle this substituted parameter pack yet");
2588   Diags.Report(Range.getBegin(), DiagID)
2589     << Range;
2590 }
2591 
2592 // <type> ::= <pointer-type>
2593 // <pointer-type> ::= E? <pointer-cvr-qualifiers> <cvr-qualifiers> <type>
2594 //                       # the E is required for 64-bit non-static pointers
2595 void MicrosoftCXXNameMangler::mangleType(const PointerType *T, Qualifiers Quals,
2596                                          SourceRange Range) {
2597   QualType PointeeType = T->getPointeeType();
2598   manglePointerCVQualifiers(Quals);
2599   manglePointerExtQualifiers(Quals, PointeeType);
2600 
2601   if (PointeeType.getQualifiers().hasAddressSpace())
2602     mangleAddressSpaceType(PointeeType, PointeeType.getQualifiers(), Range);
2603   else
2604     mangleType(PointeeType, Range);
2605 }
2606 
2607 void MicrosoftCXXNameMangler::mangleType(const ObjCObjectPointerType *T,
2608                                          Qualifiers Quals, SourceRange Range) {
2609   QualType PointeeType = T->getPointeeType();
2610   switch (Quals.getObjCLifetime()) {
2611   case Qualifiers::OCL_None:
2612   case Qualifiers::OCL_ExplicitNone:
2613     break;
2614   case Qualifiers::OCL_Autoreleasing:
2615   case Qualifiers::OCL_Strong:
2616   case Qualifiers::OCL_Weak:
2617     return mangleObjCLifetime(PointeeType, Quals, Range);
2618   }
2619   manglePointerCVQualifiers(Quals);
2620   manglePointerExtQualifiers(Quals, PointeeType);
2621   mangleType(PointeeType, Range);
2622 }
2623 
2624 // <type> ::= <reference-type>
2625 // <reference-type> ::= A E? <cvr-qualifiers> <type>
2626 //                 # the E is required for 64-bit non-static lvalue references
2627 void MicrosoftCXXNameMangler::mangleType(const LValueReferenceType *T,
2628                                          Qualifiers Quals, SourceRange Range) {
2629   QualType PointeeType = T->getPointeeType();
2630   assert(!Quals.hasConst() && !Quals.hasVolatile() && "unexpected qualifier!");
2631   Out << 'A';
2632   manglePointerExtQualifiers(Quals, PointeeType);
2633   mangleType(PointeeType, Range);
2634 }
2635 
2636 // <type> ::= <r-value-reference-type>
2637 // <r-value-reference-type> ::= $$Q E? <cvr-qualifiers> <type>
2638 //                 # the E is required for 64-bit non-static rvalue references
2639 void MicrosoftCXXNameMangler::mangleType(const RValueReferenceType *T,
2640                                          Qualifiers Quals, SourceRange Range) {
2641   QualType PointeeType = T->getPointeeType();
2642   assert(!Quals.hasConst() && !Quals.hasVolatile() && "unexpected qualifier!");
2643   Out << "$$Q";
2644   manglePointerExtQualifiers(Quals, PointeeType);
2645   mangleType(PointeeType, Range);
2646 }
2647 
2648 void MicrosoftCXXNameMangler::mangleType(const ComplexType *T, Qualifiers,
2649                                          SourceRange Range) {
2650   QualType ElementType = T->getElementType();
2651 
2652   llvm::SmallString<64> TemplateMangling;
2653   llvm::raw_svector_ostream Stream(TemplateMangling);
2654   MicrosoftCXXNameMangler Extra(Context, Stream);
2655   Stream << "?$";
2656   Extra.mangleSourceName("_Complex");
2657   Extra.mangleType(ElementType, Range, QMM_Escape);
2658 
2659   mangleArtificialTagType(TTK_Struct, TemplateMangling, {"__clang"});
2660 }
2661 
2662 // Returns true for types that mangleArtificialTagType() gets called for with
2663 // TTK_Union, TTK_Struct, TTK_Class and where compatibility with MSVC's
2664 // mangling matters.
2665 // (It doesn't matter for Objective-C types and the like that cl.exe doesn't
2666 // support.)
2667 bool MicrosoftCXXNameMangler::isArtificialTagType(QualType T) const {
2668   const Type *ty = T.getTypePtr();
2669   switch (ty->getTypeClass()) {
2670   default:
2671     return false;
2672 
2673   case Type::Vector: {
2674     // For ABI compatibility only __m64, __m128(id), and __m256(id) matter,
2675     // but since mangleType(VectorType*) always calls mangleArtificialTagType()
2676     // just always return true (the other vector types are clang-only).
2677     return true;
2678   }
2679   }
2680 }
2681 
2682 void MicrosoftCXXNameMangler::mangleType(const VectorType *T, Qualifiers Quals,
2683                                          SourceRange Range) {
2684   const BuiltinType *ET = T->getElementType()->getAs<BuiltinType>();
2685   assert(ET && "vectors with non-builtin elements are unsupported");
2686   uint64_t Width = getASTContext().getTypeSize(T);
2687   // Pattern match exactly the typedefs in our intrinsic headers.  Anything that
2688   // doesn't match the Intel types uses a custom mangling below.
2689   size_t OutSizeBefore = Out.tell();
2690   if (!isa<ExtVectorType>(T)) {
2691     llvm::Triple::ArchType AT =
2692         getASTContext().getTargetInfo().getTriple().getArch();
2693     if (AT == llvm::Triple::x86 || AT == llvm::Triple::x86_64) {
2694       if (Width == 64 && ET->getKind() == BuiltinType::LongLong) {
2695         mangleArtificialTagType(TTK_Union, "__m64");
2696       } else if (Width >= 128) {
2697         if (ET->getKind() == BuiltinType::Float)
2698           mangleArtificialTagType(TTK_Union, "__m" + llvm::utostr(Width));
2699         else if (ET->getKind() == BuiltinType::LongLong)
2700           mangleArtificialTagType(TTK_Union, "__m" + llvm::utostr(Width) + 'i');
2701         else if (ET->getKind() == BuiltinType::Double)
2702           mangleArtificialTagType(TTK_Struct, "__m" + llvm::utostr(Width) + 'd');
2703       }
2704     }
2705   }
2706 
2707   bool IsBuiltin = Out.tell() != OutSizeBefore;
2708   if (!IsBuiltin) {
2709     // The MS ABI doesn't have a special mangling for vector types, so we define
2710     // our own mangling to handle uses of __vector_size__ on user-specified
2711     // types, and for extensions like __v4sf.
2712 
2713     llvm::SmallString<64> TemplateMangling;
2714     llvm::raw_svector_ostream Stream(TemplateMangling);
2715     MicrosoftCXXNameMangler Extra(Context, Stream);
2716     Stream << "?$";
2717     Extra.mangleSourceName("__vector");
2718     Extra.mangleType(QualType(ET, 0), Range, QMM_Escape);
2719     Extra.mangleIntegerLiteral(llvm::APSInt::getUnsigned(T->getNumElements()),
2720                                /*IsBoolean=*/false);
2721 
2722     mangleArtificialTagType(TTK_Union, TemplateMangling, {"__clang"});
2723   }
2724 }
2725 
2726 void MicrosoftCXXNameMangler::mangleType(const ExtVectorType *T,
2727                                          Qualifiers Quals, SourceRange Range) {
2728   mangleType(static_cast<const VectorType *>(T), Quals, Range);
2729 }
2730 
2731 void MicrosoftCXXNameMangler::mangleType(const DependentVectorType *T,
2732                                          Qualifiers, SourceRange Range) {
2733   DiagnosticsEngine &Diags = Context.getDiags();
2734   unsigned DiagID = Diags.getCustomDiagID(
2735       DiagnosticsEngine::Error,
2736       "cannot mangle this dependent-sized vector type yet");
2737   Diags.Report(Range.getBegin(), DiagID) << Range;
2738 }
2739 
2740 void MicrosoftCXXNameMangler::mangleType(const DependentSizedExtVectorType *T,
2741                                          Qualifiers, SourceRange Range) {
2742   DiagnosticsEngine &Diags = Context.getDiags();
2743   unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
2744     "cannot mangle this dependent-sized extended vector type yet");
2745   Diags.Report(Range.getBegin(), DiagID)
2746     << Range;
2747 }
2748 
2749 void MicrosoftCXXNameMangler::mangleType(const DependentAddressSpaceType *T,
2750                                          Qualifiers, SourceRange Range) {
2751   DiagnosticsEngine &Diags = Context.getDiags();
2752   unsigned DiagID = Diags.getCustomDiagID(
2753       DiagnosticsEngine::Error,
2754       "cannot mangle this dependent address space type yet");
2755   Diags.Report(Range.getBegin(), DiagID) << Range;
2756 }
2757 
2758 void MicrosoftCXXNameMangler::mangleType(const ObjCInterfaceType *T, Qualifiers,
2759                                          SourceRange) {
2760   // ObjC interfaces have structs underlying them.
2761   mangleTagTypeKind(TTK_Struct);
2762   mangleName(T->getDecl());
2763 }
2764 
2765 void MicrosoftCXXNameMangler::mangleType(const ObjCObjectType *T,
2766                                          Qualifiers Quals, SourceRange Range) {
2767   if (T->isKindOfType())
2768     return mangleObjCKindOfType(T, Quals, Range);
2769 
2770   if (T->qual_empty() && !T->isSpecialized())
2771     return mangleType(T->getBaseType(), Range, QMM_Drop);
2772 
2773   ArgBackRefMap OuterFunArgsContext;
2774   ArgBackRefMap OuterTemplateArgsContext;
2775   BackRefVec OuterTemplateContext;
2776 
2777   FunArgBackReferences.swap(OuterFunArgsContext);
2778   TemplateArgBackReferences.swap(OuterTemplateArgsContext);
2779   NameBackReferences.swap(OuterTemplateContext);
2780 
2781   mangleTagTypeKind(TTK_Struct);
2782 
2783   Out << "?$";
2784   if (T->isObjCId())
2785     mangleSourceName("objc_object");
2786   else if (T->isObjCClass())
2787     mangleSourceName("objc_class");
2788   else
2789     mangleSourceName(T->getInterface()->getName());
2790 
2791   for (const auto &Q : T->quals())
2792     mangleObjCProtocol(Q);
2793 
2794   if (T->isSpecialized())
2795     for (const auto &TA : T->getTypeArgs())
2796       mangleType(TA, Range, QMM_Drop);
2797 
2798   Out << '@';
2799 
2800   Out << '@';
2801 
2802   FunArgBackReferences.swap(OuterFunArgsContext);
2803   TemplateArgBackReferences.swap(OuterTemplateArgsContext);
2804   NameBackReferences.swap(OuterTemplateContext);
2805 }
2806 
2807 void MicrosoftCXXNameMangler::mangleType(const BlockPointerType *T,
2808                                          Qualifiers Quals, SourceRange Range) {
2809   QualType PointeeType = T->getPointeeType();
2810   manglePointerCVQualifiers(Quals);
2811   manglePointerExtQualifiers(Quals, PointeeType);
2812 
2813   Out << "_E";
2814 
2815   mangleFunctionType(PointeeType->castAs<FunctionProtoType>());
2816 }
2817 
2818 void MicrosoftCXXNameMangler::mangleType(const InjectedClassNameType *,
2819                                          Qualifiers, SourceRange) {
2820   llvm_unreachable("Cannot mangle injected class name type.");
2821 }
2822 
2823 void MicrosoftCXXNameMangler::mangleType(const TemplateSpecializationType *T,
2824                                          Qualifiers, SourceRange Range) {
2825   DiagnosticsEngine &Diags = Context.getDiags();
2826   unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
2827     "cannot mangle this template specialization type yet");
2828   Diags.Report(Range.getBegin(), DiagID)
2829     << Range;
2830 }
2831 
2832 void MicrosoftCXXNameMangler::mangleType(const DependentNameType *T, Qualifiers,
2833                                          SourceRange Range) {
2834   DiagnosticsEngine &Diags = Context.getDiags();
2835   unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
2836     "cannot mangle this dependent name type yet");
2837   Diags.Report(Range.getBegin(), DiagID)
2838     << Range;
2839 }
2840 
2841 void MicrosoftCXXNameMangler::mangleType(
2842     const DependentTemplateSpecializationType *T, Qualifiers,
2843     SourceRange Range) {
2844   DiagnosticsEngine &Diags = Context.getDiags();
2845   unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
2846     "cannot mangle this dependent template specialization type yet");
2847   Diags.Report(Range.getBegin(), DiagID)
2848     << Range;
2849 }
2850 
2851 void MicrosoftCXXNameMangler::mangleType(const PackExpansionType *T, Qualifiers,
2852                                          SourceRange Range) {
2853   DiagnosticsEngine &Diags = Context.getDiags();
2854   unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
2855     "cannot mangle this pack expansion yet");
2856   Diags.Report(Range.getBegin(), DiagID)
2857     << Range;
2858 }
2859 
2860 void MicrosoftCXXNameMangler::mangleType(const TypeOfType *T, Qualifiers,
2861                                          SourceRange Range) {
2862   DiagnosticsEngine &Diags = Context.getDiags();
2863   unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
2864     "cannot mangle this typeof(type) yet");
2865   Diags.Report(Range.getBegin(), DiagID)
2866     << Range;
2867 }
2868 
2869 void MicrosoftCXXNameMangler::mangleType(const TypeOfExprType *T, Qualifiers,
2870                                          SourceRange Range) {
2871   DiagnosticsEngine &Diags = Context.getDiags();
2872   unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
2873     "cannot mangle this typeof(expression) yet");
2874   Diags.Report(Range.getBegin(), DiagID)
2875     << Range;
2876 }
2877 
2878 void MicrosoftCXXNameMangler::mangleType(const DecltypeType *T, Qualifiers,
2879                                          SourceRange Range) {
2880   DiagnosticsEngine &Diags = Context.getDiags();
2881   unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
2882     "cannot mangle this decltype() yet");
2883   Diags.Report(Range.getBegin(), DiagID)
2884     << Range;
2885 }
2886 
2887 void MicrosoftCXXNameMangler::mangleType(const UnaryTransformType *T,
2888                                          Qualifiers, SourceRange Range) {
2889   DiagnosticsEngine &Diags = Context.getDiags();
2890   unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
2891     "cannot mangle this unary transform type yet");
2892   Diags.Report(Range.getBegin(), DiagID)
2893     << Range;
2894 }
2895 
2896 void MicrosoftCXXNameMangler::mangleType(const AutoType *T, Qualifiers,
2897                                          SourceRange Range) {
2898   assert(T->getDeducedType().isNull() && "expecting a dependent type!");
2899 
2900   DiagnosticsEngine &Diags = Context.getDiags();
2901   unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
2902     "cannot mangle this 'auto' type yet");
2903   Diags.Report(Range.getBegin(), DiagID)
2904     << Range;
2905 }
2906 
2907 void MicrosoftCXXNameMangler::mangleType(
2908     const DeducedTemplateSpecializationType *T, Qualifiers, SourceRange Range) {
2909   assert(T->getDeducedType().isNull() && "expecting a dependent type!");
2910 
2911   DiagnosticsEngine &Diags = Context.getDiags();
2912   unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
2913     "cannot mangle this deduced class template specialization type yet");
2914   Diags.Report(Range.getBegin(), DiagID)
2915     << Range;
2916 }
2917 
2918 void MicrosoftCXXNameMangler::mangleType(const AtomicType *T, Qualifiers,
2919                                          SourceRange Range) {
2920   QualType ValueType = T->getValueType();
2921 
2922   llvm::SmallString<64> TemplateMangling;
2923   llvm::raw_svector_ostream Stream(TemplateMangling);
2924   MicrosoftCXXNameMangler Extra(Context, Stream);
2925   Stream << "?$";
2926   Extra.mangleSourceName("_Atomic");
2927   Extra.mangleType(ValueType, Range, QMM_Escape);
2928 
2929   mangleArtificialTagType(TTK_Struct, TemplateMangling, {"__clang"});
2930 }
2931 
2932 void MicrosoftCXXNameMangler::mangleType(const PipeType *T, Qualifiers,
2933                                          SourceRange Range) {
2934   DiagnosticsEngine &Diags = Context.getDiags();
2935   unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
2936     "cannot mangle this OpenCL pipe type yet");
2937   Diags.Report(Range.getBegin(), DiagID)
2938     << Range;
2939 }
2940 
2941 void MicrosoftMangleContextImpl::mangleCXXName(const NamedDecl *D,
2942                                                raw_ostream &Out) {
2943   assert((isa<FunctionDecl>(D) || isa<VarDecl>(D)) &&
2944          "Invalid mangleName() call, argument is not a variable or function!");
2945   assert(!isa<CXXConstructorDecl>(D) && !isa<CXXDestructorDecl>(D) &&
2946          "Invalid mangleName() call on 'structor decl!");
2947 
2948   PrettyStackTraceDecl CrashInfo(D, SourceLocation(),
2949                                  getASTContext().getSourceManager(),
2950                                  "Mangling declaration");
2951 
2952   msvc_hashing_ostream MHO(Out);
2953   MicrosoftCXXNameMangler Mangler(*this, MHO);
2954   return Mangler.mangle(D);
2955 }
2956 
2957 // <this-adjustment> ::= <no-adjustment> | <static-adjustment> |
2958 //                       <virtual-adjustment>
2959 // <no-adjustment>      ::= A # private near
2960 //                      ::= B # private far
2961 //                      ::= I # protected near
2962 //                      ::= J # protected far
2963 //                      ::= Q # public near
2964 //                      ::= R # public far
2965 // <static-adjustment>  ::= G <static-offset> # private near
2966 //                      ::= H <static-offset> # private far
2967 //                      ::= O <static-offset> # protected near
2968 //                      ::= P <static-offset> # protected far
2969 //                      ::= W <static-offset> # public near
2970 //                      ::= X <static-offset> # public far
2971 // <virtual-adjustment> ::= $0 <virtual-shift> <static-offset> # private near
2972 //                      ::= $1 <virtual-shift> <static-offset> # private far
2973 //                      ::= $2 <virtual-shift> <static-offset> # protected near
2974 //                      ::= $3 <virtual-shift> <static-offset> # protected far
2975 //                      ::= $4 <virtual-shift> <static-offset> # public near
2976 //                      ::= $5 <virtual-shift> <static-offset> # public far
2977 // <virtual-shift>      ::= <vtordisp-shift> | <vtordispex-shift>
2978 // <vtordisp-shift>     ::= <offset-to-vtordisp>
2979 // <vtordispex-shift>   ::= <offset-to-vbptr> <vbase-offset-offset>
2980 //                          <offset-to-vtordisp>
2981 static void mangleThunkThisAdjustment(AccessSpecifier AS,
2982                                       const ThisAdjustment &Adjustment,
2983                                       MicrosoftCXXNameMangler &Mangler,
2984                                       raw_ostream &Out) {
2985   if (!Adjustment.Virtual.isEmpty()) {
2986     Out << '$';
2987     char AccessSpec;
2988     switch (AS) {
2989     case AS_none:
2990       llvm_unreachable("Unsupported access specifier");
2991     case AS_private:
2992       AccessSpec = '0';
2993       break;
2994     case AS_protected:
2995       AccessSpec = '2';
2996       break;
2997     case AS_public:
2998       AccessSpec = '4';
2999     }
3000     if (Adjustment.Virtual.Microsoft.VBPtrOffset) {
3001       Out << 'R' << AccessSpec;
3002       Mangler.mangleNumber(
3003           static_cast<uint32_t>(Adjustment.Virtual.Microsoft.VBPtrOffset));
3004       Mangler.mangleNumber(
3005           static_cast<uint32_t>(Adjustment.Virtual.Microsoft.VBOffsetOffset));
3006       Mangler.mangleNumber(
3007           static_cast<uint32_t>(Adjustment.Virtual.Microsoft.VtordispOffset));
3008       Mangler.mangleNumber(static_cast<uint32_t>(Adjustment.NonVirtual));
3009     } else {
3010       Out << AccessSpec;
3011       Mangler.mangleNumber(
3012           static_cast<uint32_t>(Adjustment.Virtual.Microsoft.VtordispOffset));
3013       Mangler.mangleNumber(-static_cast<uint32_t>(Adjustment.NonVirtual));
3014     }
3015   } else if (Adjustment.NonVirtual != 0) {
3016     switch (AS) {
3017     case AS_none:
3018       llvm_unreachable("Unsupported access specifier");
3019     case AS_private:
3020       Out << 'G';
3021       break;
3022     case AS_protected:
3023       Out << 'O';
3024       break;
3025     case AS_public:
3026       Out << 'W';
3027     }
3028     Mangler.mangleNumber(-static_cast<uint32_t>(Adjustment.NonVirtual));
3029   } else {
3030     switch (AS) {
3031     case AS_none:
3032       llvm_unreachable("Unsupported access specifier");
3033     case AS_private:
3034       Out << 'A';
3035       break;
3036     case AS_protected:
3037       Out << 'I';
3038       break;
3039     case AS_public:
3040       Out << 'Q';
3041     }
3042   }
3043 }
3044 
3045 void MicrosoftMangleContextImpl::mangleVirtualMemPtrThunk(
3046     const CXXMethodDecl *MD, const MethodVFTableLocation &ML,
3047     raw_ostream &Out) {
3048   msvc_hashing_ostream MHO(Out);
3049   MicrosoftCXXNameMangler Mangler(*this, MHO);
3050   Mangler.getStream() << '?';
3051   Mangler.mangleVirtualMemPtrThunk(MD, ML);
3052 }
3053 
3054 void MicrosoftMangleContextImpl::mangleThunk(const CXXMethodDecl *MD,
3055                                              const ThunkInfo &Thunk,
3056                                              raw_ostream &Out) {
3057   msvc_hashing_ostream MHO(Out);
3058   MicrosoftCXXNameMangler Mangler(*this, MHO);
3059   Mangler.getStream() << '?';
3060   Mangler.mangleName(MD);
3061 
3062   // Usually the thunk uses the access specifier of the new method, but if this
3063   // is a covariant return thunk, then MSVC always uses the public access
3064   // specifier, and we do the same.
3065   AccessSpecifier AS = Thunk.Return.isEmpty() ? MD->getAccess() : AS_public;
3066   mangleThunkThisAdjustment(AS, Thunk.This, Mangler, MHO);
3067 
3068   if (!Thunk.Return.isEmpty())
3069     assert(Thunk.Method != nullptr &&
3070            "Thunk info should hold the overridee decl");
3071 
3072   const CXXMethodDecl *DeclForFPT = Thunk.Method ? Thunk.Method : MD;
3073   Mangler.mangleFunctionType(
3074       DeclForFPT->getType()->castAs<FunctionProtoType>(), MD);
3075 }
3076 
3077 void MicrosoftMangleContextImpl::mangleCXXDtorThunk(
3078     const CXXDestructorDecl *DD, CXXDtorType Type,
3079     const ThisAdjustment &Adjustment, raw_ostream &Out) {
3080   // FIXME: Actually, the dtor thunk should be emitted for vector deleting
3081   // dtors rather than scalar deleting dtors. Just use the vector deleting dtor
3082   // mangling manually until we support both deleting dtor types.
3083   assert(Type == Dtor_Deleting);
3084   msvc_hashing_ostream MHO(Out);
3085   MicrosoftCXXNameMangler Mangler(*this, MHO, DD, Type);
3086   Mangler.getStream() << "??_E";
3087   Mangler.mangleName(DD->getParent());
3088   mangleThunkThisAdjustment(DD->getAccess(), Adjustment, Mangler, MHO);
3089   Mangler.mangleFunctionType(DD->getType()->castAs<FunctionProtoType>(), DD);
3090 }
3091 
3092 void MicrosoftMangleContextImpl::mangleCXXVFTable(
3093     const CXXRecordDecl *Derived, ArrayRef<const CXXRecordDecl *> BasePath,
3094     raw_ostream &Out) {
3095   // <mangled-name> ::= ?_7 <class-name> <storage-class>
3096   //                    <cvr-qualifiers> [<name>] @
3097   // NOTE: <cvr-qualifiers> here is always 'B' (const). <storage-class>
3098   // is always '6' for vftables.
3099   msvc_hashing_ostream MHO(Out);
3100   MicrosoftCXXNameMangler Mangler(*this, MHO);
3101   if (Derived->hasAttr<DLLImportAttr>())
3102     Mangler.getStream() << "??_S";
3103   else
3104     Mangler.getStream() << "??_7";
3105   Mangler.mangleName(Derived);
3106   Mangler.getStream() << "6B"; // '6' for vftable, 'B' for const.
3107   for (const CXXRecordDecl *RD : BasePath)
3108     Mangler.mangleName(RD);
3109   Mangler.getStream() << '@';
3110 }
3111 
3112 void MicrosoftMangleContextImpl::mangleCXXVBTable(
3113     const CXXRecordDecl *Derived, ArrayRef<const CXXRecordDecl *> BasePath,
3114     raw_ostream &Out) {
3115   // <mangled-name> ::= ?_8 <class-name> <storage-class>
3116   //                    <cvr-qualifiers> [<name>] @
3117   // NOTE: <cvr-qualifiers> here is always 'B' (const). <storage-class>
3118   // is always '7' for vbtables.
3119   msvc_hashing_ostream MHO(Out);
3120   MicrosoftCXXNameMangler Mangler(*this, MHO);
3121   Mangler.getStream() << "??_8";
3122   Mangler.mangleName(Derived);
3123   Mangler.getStream() << "7B";  // '7' for vbtable, 'B' for const.
3124   for (const CXXRecordDecl *RD : BasePath)
3125     Mangler.mangleName(RD);
3126   Mangler.getStream() << '@';
3127 }
3128 
3129 void MicrosoftMangleContextImpl::mangleCXXRTTI(QualType T, raw_ostream &Out) {
3130   msvc_hashing_ostream MHO(Out);
3131   MicrosoftCXXNameMangler Mangler(*this, MHO);
3132   Mangler.getStream() << "??_R0";
3133   Mangler.mangleType(T, SourceRange(), MicrosoftCXXNameMangler::QMM_Result);
3134   Mangler.getStream() << "@8";
3135 }
3136 
3137 void MicrosoftMangleContextImpl::mangleCXXRTTIName(QualType T,
3138                                                    raw_ostream &Out) {
3139   MicrosoftCXXNameMangler Mangler(*this, Out);
3140   Mangler.getStream() << '.';
3141   Mangler.mangleType(T, SourceRange(), MicrosoftCXXNameMangler::QMM_Result);
3142 }
3143 
3144 void MicrosoftMangleContextImpl::mangleCXXVirtualDisplacementMap(
3145     const CXXRecordDecl *SrcRD, const CXXRecordDecl *DstRD, raw_ostream &Out) {
3146   msvc_hashing_ostream MHO(Out);
3147   MicrosoftCXXNameMangler Mangler(*this, MHO);
3148   Mangler.getStream() << "??_K";
3149   Mangler.mangleName(SrcRD);
3150   Mangler.getStream() << "$C";
3151   Mangler.mangleName(DstRD);
3152 }
3153 
3154 void MicrosoftMangleContextImpl::mangleCXXThrowInfo(QualType T, bool IsConst,
3155                                                     bool IsVolatile,
3156                                                     bool IsUnaligned,
3157                                                     uint32_t NumEntries,
3158                                                     raw_ostream &Out) {
3159   msvc_hashing_ostream MHO(Out);
3160   MicrosoftCXXNameMangler Mangler(*this, MHO);
3161   Mangler.getStream() << "_TI";
3162   if (IsConst)
3163     Mangler.getStream() << 'C';
3164   if (IsVolatile)
3165     Mangler.getStream() << 'V';
3166   if (IsUnaligned)
3167     Mangler.getStream() << 'U';
3168   Mangler.getStream() << NumEntries;
3169   Mangler.mangleType(T, SourceRange(), MicrosoftCXXNameMangler::QMM_Result);
3170 }
3171 
3172 void MicrosoftMangleContextImpl::mangleCXXCatchableTypeArray(
3173     QualType T, uint32_t NumEntries, raw_ostream &Out) {
3174   msvc_hashing_ostream MHO(Out);
3175   MicrosoftCXXNameMangler Mangler(*this, MHO);
3176   Mangler.getStream() << "_CTA";
3177   Mangler.getStream() << NumEntries;
3178   Mangler.mangleType(T, SourceRange(), MicrosoftCXXNameMangler::QMM_Result);
3179 }
3180 
3181 void MicrosoftMangleContextImpl::mangleCXXCatchableType(
3182     QualType T, const CXXConstructorDecl *CD, CXXCtorType CT, uint32_t Size,
3183     uint32_t NVOffset, int32_t VBPtrOffset, uint32_t VBIndex,
3184     raw_ostream &Out) {
3185   MicrosoftCXXNameMangler Mangler(*this, Out);
3186   Mangler.getStream() << "_CT";
3187 
3188   llvm::SmallString<64> RTTIMangling;
3189   {
3190     llvm::raw_svector_ostream Stream(RTTIMangling);
3191     msvc_hashing_ostream MHO(Stream);
3192     mangleCXXRTTI(T, MHO);
3193   }
3194   Mangler.getStream() << RTTIMangling;
3195 
3196   // VS2015 and VS2017.1 omit the copy-constructor in the mangled name but
3197   // both older and newer versions include it.
3198   // FIXME: It is known that the Ctor is present in 2013, and in 2017.7
3199   // (_MSC_VER 1914) and newer, and that it's omitted in 2015 and 2017.4
3200   // (_MSC_VER 1911), but it's unknown when exactly it reappeared (1914?
3201   // Or 1912, 1913 aleady?).
3202   bool OmitCopyCtor = getASTContext().getLangOpts().isCompatibleWithMSVC(
3203                           LangOptions::MSVC2015) &&
3204                       !getASTContext().getLangOpts().isCompatibleWithMSVC(
3205                           LangOptions::MSVC2017_7);
3206   llvm::SmallString<64> CopyCtorMangling;
3207   if (!OmitCopyCtor && CD) {
3208     llvm::raw_svector_ostream Stream(CopyCtorMangling);
3209     msvc_hashing_ostream MHO(Stream);
3210     mangleCXXCtor(CD, CT, MHO);
3211   }
3212   Mangler.getStream() << CopyCtorMangling;
3213 
3214   Mangler.getStream() << Size;
3215   if (VBPtrOffset == -1) {
3216     if (NVOffset) {
3217       Mangler.getStream() << NVOffset;
3218     }
3219   } else {
3220     Mangler.getStream() << NVOffset;
3221     Mangler.getStream() << VBPtrOffset;
3222     Mangler.getStream() << VBIndex;
3223   }
3224 }
3225 
3226 void MicrosoftMangleContextImpl::mangleCXXRTTIBaseClassDescriptor(
3227     const CXXRecordDecl *Derived, uint32_t NVOffset, int32_t VBPtrOffset,
3228     uint32_t VBTableOffset, uint32_t Flags, raw_ostream &Out) {
3229   msvc_hashing_ostream MHO(Out);
3230   MicrosoftCXXNameMangler Mangler(*this, MHO);
3231   Mangler.getStream() << "??_R1";
3232   Mangler.mangleNumber(NVOffset);
3233   Mangler.mangleNumber(VBPtrOffset);
3234   Mangler.mangleNumber(VBTableOffset);
3235   Mangler.mangleNumber(Flags);
3236   Mangler.mangleName(Derived);
3237   Mangler.getStream() << "8";
3238 }
3239 
3240 void MicrosoftMangleContextImpl::mangleCXXRTTIBaseClassArray(
3241     const CXXRecordDecl *Derived, raw_ostream &Out) {
3242   msvc_hashing_ostream MHO(Out);
3243   MicrosoftCXXNameMangler Mangler(*this, MHO);
3244   Mangler.getStream() << "??_R2";
3245   Mangler.mangleName(Derived);
3246   Mangler.getStream() << "8";
3247 }
3248 
3249 void MicrosoftMangleContextImpl::mangleCXXRTTIClassHierarchyDescriptor(
3250     const CXXRecordDecl *Derived, raw_ostream &Out) {
3251   msvc_hashing_ostream MHO(Out);
3252   MicrosoftCXXNameMangler Mangler(*this, MHO);
3253   Mangler.getStream() << "??_R3";
3254   Mangler.mangleName(Derived);
3255   Mangler.getStream() << "8";
3256 }
3257 
3258 void MicrosoftMangleContextImpl::mangleCXXRTTICompleteObjectLocator(
3259     const CXXRecordDecl *Derived, ArrayRef<const CXXRecordDecl *> BasePath,
3260     raw_ostream &Out) {
3261   // <mangled-name> ::= ?_R4 <class-name> <storage-class>
3262   //                    <cvr-qualifiers> [<name>] @
3263   // NOTE: <cvr-qualifiers> here is always 'B' (const). <storage-class>
3264   // is always '6' for vftables.
3265   llvm::SmallString<64> VFTableMangling;
3266   llvm::raw_svector_ostream Stream(VFTableMangling);
3267   mangleCXXVFTable(Derived, BasePath, Stream);
3268 
3269   if (VFTableMangling.startswith("??@")) {
3270     assert(VFTableMangling.endswith("@"));
3271     Out << VFTableMangling << "??_R4@";
3272     return;
3273   }
3274 
3275   assert(VFTableMangling.startswith("??_7") ||
3276          VFTableMangling.startswith("??_S"));
3277 
3278   Out << "??_R4" << StringRef(VFTableMangling).drop_front(4);
3279 }
3280 
3281 void MicrosoftMangleContextImpl::mangleSEHFilterExpression(
3282     const NamedDecl *EnclosingDecl, raw_ostream &Out) {
3283   msvc_hashing_ostream MHO(Out);
3284   MicrosoftCXXNameMangler Mangler(*this, MHO);
3285   // The function body is in the same comdat as the function with the handler,
3286   // so the numbering here doesn't have to be the same across TUs.
3287   //
3288   // <mangled-name> ::= ?filt$ <filter-number> @0
3289   Mangler.getStream() << "?filt$" << SEHFilterIds[EnclosingDecl]++ << "@0@";
3290   Mangler.mangleName(EnclosingDecl);
3291 }
3292 
3293 void MicrosoftMangleContextImpl::mangleSEHFinallyBlock(
3294     const NamedDecl *EnclosingDecl, raw_ostream &Out) {
3295   msvc_hashing_ostream MHO(Out);
3296   MicrosoftCXXNameMangler Mangler(*this, MHO);
3297   // The function body is in the same comdat as the function with the handler,
3298   // so the numbering here doesn't have to be the same across TUs.
3299   //
3300   // <mangled-name> ::= ?fin$ <filter-number> @0
3301   Mangler.getStream() << "?fin$" << SEHFinallyIds[EnclosingDecl]++ << "@0@";
3302   Mangler.mangleName(EnclosingDecl);
3303 }
3304 
3305 void MicrosoftMangleContextImpl::mangleTypeName(QualType T, raw_ostream &Out) {
3306   // This is just a made up unique string for the purposes of tbaa.  undname
3307   // does *not* know how to demangle it.
3308   MicrosoftCXXNameMangler Mangler(*this, Out);
3309   Mangler.getStream() << '?';
3310   Mangler.mangleType(T, SourceRange());
3311 }
3312 
3313 void MicrosoftMangleContextImpl::mangleCXXCtor(const CXXConstructorDecl *D,
3314                                                CXXCtorType Type,
3315                                                raw_ostream &Out) {
3316   msvc_hashing_ostream MHO(Out);
3317   MicrosoftCXXNameMangler mangler(*this, MHO, D, Type);
3318   mangler.mangle(D);
3319 }
3320 
3321 void MicrosoftMangleContextImpl::mangleCXXDtor(const CXXDestructorDecl *D,
3322                                                CXXDtorType Type,
3323                                                raw_ostream &Out) {
3324   msvc_hashing_ostream MHO(Out);
3325   MicrosoftCXXNameMangler mangler(*this, MHO, D, Type);
3326   mangler.mangle(D);
3327 }
3328 
3329 void MicrosoftMangleContextImpl::mangleReferenceTemporary(
3330     const VarDecl *VD, unsigned ManglingNumber, raw_ostream &Out) {
3331   msvc_hashing_ostream MHO(Out);
3332   MicrosoftCXXNameMangler Mangler(*this, MHO);
3333 
3334   Mangler.getStream() << "?$RT" << ManglingNumber << '@';
3335   Mangler.mangle(VD, "");
3336 }
3337 
3338 void MicrosoftMangleContextImpl::mangleThreadSafeStaticGuardVariable(
3339     const VarDecl *VD, unsigned GuardNum, raw_ostream &Out) {
3340   msvc_hashing_ostream MHO(Out);
3341   MicrosoftCXXNameMangler Mangler(*this, MHO);
3342 
3343   Mangler.getStream() << "?$TSS" << GuardNum << '@';
3344   Mangler.mangleNestedName(VD);
3345   Mangler.getStream() << "@4HA";
3346 }
3347 
3348 void MicrosoftMangleContextImpl::mangleStaticGuardVariable(const VarDecl *VD,
3349                                                            raw_ostream &Out) {
3350   // <guard-name> ::= ?_B <postfix> @5 <scope-depth>
3351   //              ::= ?__J <postfix> @5 <scope-depth>
3352   //              ::= ?$S <guard-num> @ <postfix> @4IA
3353 
3354   // The first mangling is what MSVC uses to guard static locals in inline
3355   // functions.  It uses a different mangling in external functions to support
3356   // guarding more than 32 variables.  MSVC rejects inline functions with more
3357   // than 32 static locals.  We don't fully implement the second mangling
3358   // because those guards are not externally visible, and instead use LLVM's
3359   // default renaming when creating a new guard variable.
3360   msvc_hashing_ostream MHO(Out);
3361   MicrosoftCXXNameMangler Mangler(*this, MHO);
3362 
3363   bool Visible = VD->isExternallyVisible();
3364   if (Visible) {
3365     Mangler.getStream() << (VD->getTLSKind() ? "??__J" : "??_B");
3366   } else {
3367     Mangler.getStream() << "?$S1@";
3368   }
3369   unsigned ScopeDepth = 0;
3370   if (Visible && !getNextDiscriminator(VD, ScopeDepth))
3371     // If we do not have a discriminator and are emitting a guard variable for
3372     // use at global scope, then mangling the nested name will not be enough to
3373     // remove ambiguities.
3374     Mangler.mangle(VD, "");
3375   else
3376     Mangler.mangleNestedName(VD);
3377   Mangler.getStream() << (Visible ? "@5" : "@4IA");
3378   if (ScopeDepth)
3379     Mangler.mangleNumber(ScopeDepth);
3380 }
3381 
3382 void MicrosoftMangleContextImpl::mangleInitFiniStub(const VarDecl *D,
3383                                                     char CharCode,
3384                                                     raw_ostream &Out) {
3385   msvc_hashing_ostream MHO(Out);
3386   MicrosoftCXXNameMangler Mangler(*this, MHO);
3387   Mangler.getStream() << "??__" << CharCode;
3388   if (D->isStaticDataMember()) {
3389     Mangler.getStream() << '?';
3390     Mangler.mangleName(D);
3391     Mangler.mangleVariableEncoding(D);
3392     Mangler.getStream() << "@@";
3393   } else {
3394     Mangler.mangleName(D);
3395   }
3396   // This is the function class mangling.  These stubs are global, non-variadic,
3397   // cdecl functions that return void and take no args.
3398   Mangler.getStream() << "YAXXZ";
3399 }
3400 
3401 void MicrosoftMangleContextImpl::mangleDynamicInitializer(const VarDecl *D,
3402                                                           raw_ostream &Out) {
3403   // <initializer-name> ::= ?__E <name> YAXXZ
3404   mangleInitFiniStub(D, 'E', Out);
3405 }
3406 
3407 void
3408 MicrosoftMangleContextImpl::mangleDynamicAtExitDestructor(const VarDecl *D,
3409                                                           raw_ostream &Out) {
3410   // <destructor-name> ::= ?__F <name> YAXXZ
3411   mangleInitFiniStub(D, 'F', Out);
3412 }
3413 
3414 void MicrosoftMangleContextImpl::mangleStringLiteral(const StringLiteral *SL,
3415                                                      raw_ostream &Out) {
3416   // <char-type> ::= 0   # char, char16_t, char32_t
3417   //                     # (little endian char data in mangling)
3418   //             ::= 1   # wchar_t (big endian char data in mangling)
3419   //
3420   // <literal-length> ::= <non-negative integer>  # the length of the literal
3421   //
3422   // <encoded-crc>    ::= <hex digit>+ @          # crc of the literal including
3423   //                                              # trailing null bytes
3424   //
3425   // <encoded-string> ::= <simple character>           # uninteresting character
3426   //                  ::= '?$' <hex digit> <hex digit> # these two nibbles
3427   //                                                   # encode the byte for the
3428   //                                                   # character
3429   //                  ::= '?' [a-z]                    # \xe1 - \xfa
3430   //                  ::= '?' [A-Z]                    # \xc1 - \xda
3431   //                  ::= '?' [0-9]                    # [,/\:. \n\t'-]
3432   //
3433   // <literal> ::= '??_C@_' <char-type> <literal-length> <encoded-crc>
3434   //               <encoded-string> '@'
3435   MicrosoftCXXNameMangler Mangler(*this, Out);
3436   Mangler.getStream() << "??_C@_";
3437 
3438   // The actual string length might be different from that of the string literal
3439   // in cases like:
3440   // char foo[3] = "foobar";
3441   // char bar[42] = "foobar";
3442   // Where it is truncated or zero-padded to fit the array. This is the length
3443   // used for mangling, and any trailing null-bytes also need to be mangled.
3444   unsigned StringLength = getASTContext()
3445                               .getAsConstantArrayType(SL->getType())
3446                               ->getSize()
3447                               .getZExtValue();
3448   unsigned StringByteLength = StringLength * SL->getCharByteWidth();
3449 
3450   // <char-type>: The "kind" of string literal is encoded into the mangled name.
3451   if (SL->isWide())
3452     Mangler.getStream() << '1';
3453   else
3454     Mangler.getStream() << '0';
3455 
3456   // <literal-length>: The next part of the mangled name consists of the length
3457   // of the string in bytes.
3458   Mangler.mangleNumber(StringByteLength);
3459 
3460   auto GetLittleEndianByte = [&SL](unsigned Index) {
3461     unsigned CharByteWidth = SL->getCharByteWidth();
3462     if (Index / CharByteWidth >= SL->getLength())
3463       return static_cast<char>(0);
3464     uint32_t CodeUnit = SL->getCodeUnit(Index / CharByteWidth);
3465     unsigned OffsetInCodeUnit = Index % CharByteWidth;
3466     return static_cast<char>((CodeUnit >> (8 * OffsetInCodeUnit)) & 0xff);
3467   };
3468 
3469   auto GetBigEndianByte = [&SL](unsigned Index) {
3470     unsigned CharByteWidth = SL->getCharByteWidth();
3471     if (Index / CharByteWidth >= SL->getLength())
3472       return static_cast<char>(0);
3473     uint32_t CodeUnit = SL->getCodeUnit(Index / CharByteWidth);
3474     unsigned OffsetInCodeUnit = (CharByteWidth - 1) - (Index % CharByteWidth);
3475     return static_cast<char>((CodeUnit >> (8 * OffsetInCodeUnit)) & 0xff);
3476   };
3477 
3478   // CRC all the bytes of the StringLiteral.
3479   llvm::JamCRC JC;
3480   for (unsigned I = 0, E = StringByteLength; I != E; ++I)
3481     JC.update(GetLittleEndianByte(I));
3482 
3483   // <encoded-crc>: The CRC is encoded utilizing the standard number mangling
3484   // scheme.
3485   Mangler.mangleNumber(JC.getCRC());
3486 
3487   // <encoded-string>: The mangled name also contains the first 32 bytes
3488   // (including null-terminator bytes) of the encoded StringLiteral.
3489   // Each character is encoded by splitting them into bytes and then encoding
3490   // the constituent bytes.
3491   auto MangleByte = [&Mangler](char Byte) {
3492     // There are five different manglings for characters:
3493     // - [a-zA-Z0-9_$]: A one-to-one mapping.
3494     // - ?[a-z]: The range from \xe1 to \xfa.
3495     // - ?[A-Z]: The range from \xc1 to \xda.
3496     // - ?[0-9]: The set of [,/\:. \n\t'-].
3497     // - ?$XX: A fallback which maps nibbles.
3498     if (isIdentifierBody(Byte, /*AllowDollar=*/true)) {
3499       Mangler.getStream() << Byte;
3500     } else if (isLetter(Byte & 0x7f)) {
3501       Mangler.getStream() << '?' << static_cast<char>(Byte & 0x7f);
3502     } else {
3503       const char SpecialChars[] = {',', '/',  '\\', ':',  '.',
3504                                    ' ', '\n', '\t', '\'', '-'};
3505       const char *Pos = llvm::find(SpecialChars, Byte);
3506       if (Pos != std::end(SpecialChars)) {
3507         Mangler.getStream() << '?' << (Pos - std::begin(SpecialChars));
3508       } else {
3509         Mangler.getStream() << "?$";
3510         Mangler.getStream() << static_cast<char>('A' + ((Byte >> 4) & 0xf));
3511         Mangler.getStream() << static_cast<char>('A' + (Byte & 0xf));
3512       }
3513     }
3514   };
3515 
3516   // Enforce our 32 bytes max, except wchar_t which gets 32 chars instead.
3517   unsigned MaxBytesToMangle = SL->isWide() ? 64U : 32U;
3518   unsigned NumBytesToMangle = std::min(MaxBytesToMangle, StringByteLength);
3519   for (unsigned I = 0; I != NumBytesToMangle; ++I) {
3520     if (SL->isWide())
3521       MangleByte(GetBigEndianByte(I));
3522     else
3523       MangleByte(GetLittleEndianByte(I));
3524   }
3525 
3526   Mangler.getStream() << '@';
3527 }
3528 
3529 MicrosoftMangleContext *
3530 MicrosoftMangleContext::create(ASTContext &Context, DiagnosticsEngine &Diags) {
3531   return new MicrosoftMangleContextImpl(Context, Diags);
3532 }
3533