lib/AST/Mangle.cpp - llvm-project/clang - Git at Google

 //===--- Mangle.cpp - Mangle C++ Names --------------------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // Implements generic name mangling support for blocks and Objective-C.
 //
 //===----------------------------------------------------------------------===//
 #include "clang/AST/Attr.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/Decl.h"
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/DeclObjC.h"
 #include "clang/AST/DeclTemplate.h"
 #include "clang/AST/ExprCXX.h"
 #include "clang/AST/Mangle.h"
 #include "clang/AST/VTableBuilder.h"
 #include "clang/Basic/ABI.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/TargetInfo.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/Mangler.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"

 using namespace clang;

 // FIXME: For blocks we currently mimic GCC's mangling scheme, which leaves
 // much to be desired. Come up with a better mangling scheme.

 static void mangleFunctionBlock(MangleContext &Context,
                                 StringRef Outer,
                                 const BlockDecl *BD,
                                 raw_ostream &Out) {
   unsigned discriminator = Context.getBlockId(BD, true);
   if (discriminator == 0)
     Out << "__" << Outer << "_block_invoke";
   else
     Out << "__" << Outer << "_block_invoke_" << discriminator+1;
 }

 void MangleContext::anchor() { }

 enum CCMangling {
   CCM_Other,
   CCM_Fast,
   CCM_RegCall,
   CCM_Vector,
   CCM_Std,
   CCM_WasmMainArgcArgv
 };

 static bool isExternC(const NamedDecl *ND) {
   if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
     return FD->isExternC();
   if (const VarDecl *VD = dyn_cast<VarDecl>(ND))
     return VD->isExternC();
   return false;
 }

 static CCMangling getCallingConvMangling(const ASTContext &Context,
                                          const NamedDecl *ND) {
   const TargetInfo &TI = Context.getTargetInfo();
   const llvm::Triple &Triple = TI.getTriple();

   // On wasm, the argc/argv form of "main" is renamed so that the startup code
   // can call it with the correct function signature.
   // On Emscripten, users may be exporting "main" and expecting to call it
   // themselves, so we can't mangle it.
   if (Triple.isWasm() && !Triple.isOSEmscripten())
     if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
       if (FD->isMain() && FD->hasPrototype() && FD->param_size() == 2)
         return CCM_WasmMainArgcArgv;

   if (!Triple.isOSWindows() || !Triple.isX86())
     return CCM_Other;

   if (Context.getLangOpts().CPlusPlus && !isExternC(ND) &&
       TI.getCXXABI() == TargetCXXABI::Microsoft)
     return CCM_Other;

   const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND);
   if (!FD)
     return CCM_Other;
   QualType T = FD->getType();

   const FunctionType *FT = T->castAs<FunctionType>();

   CallingConv CC = FT->getCallConv();
   switch (CC) {
   default:
     return CCM_Other;
   case CC_X86FastCall:
     return CCM_Fast;
   case CC_X86StdCall:
     return CCM_Std;
   case CC_X86VectorCall:
     return CCM_Vector;
   }
 }

 bool MangleContext::shouldMangleDeclName(const NamedDecl *D) {
   const ASTContext &ASTContext = getASTContext();

   CCMangling CC = getCallingConvMangling(ASTContext, D);
   if (CC != CCM_Other)
     return true;

   // If the declaration has an owning module for linkage purposes that needs to
   // be mangled, we must mangle its name.
   if (!D->hasExternalFormalLinkage() && D->getOwningModuleForLinkage())
     return true;

   // In C, functions with no attributes never need to be mangled. Fastpath them.
   if (!getASTContext().getLangOpts().CPlusPlus && !D->hasAttrs())
     return false;

   // Any decl can be declared with __asm("foo") on it, and this takes precedence
   // over all other naming in the .o file.
   if (D->hasAttr<AsmLabelAttr>())
     return true;

   // Declarations that don't have identifier names always need to be mangled.
   if (isa<MSGuidDecl>(D))
     return true;

   return shouldMangleCXXName(D);
 }

 void MangleContext::mangleName(GlobalDecl GD, raw_ostream &Out) {
   const NamedDecl *D = cast<NamedDecl>(GD.getDecl());
   // Any decl can be declared with __asm("foo") on it, and this takes precedence
   // over all other naming in the .o file.
   if (const AsmLabelAttr *ALA = D->getAttr<AsmLabelAttr>()) {
     // If we have an asm name, then we use it as the mangling.

     // If the label isn't literal, or if this is an alias for an LLVM intrinsic,
     // do not add a "\01" prefix.
     if (!ALA->getIsLiteralLabel() || ALA->getLabel().startswith("llvm.")) {
       Out << ALA->getLabel();
       return;
     }

     // Adding the prefix can cause problems when one file has a "foo" and
     // another has a "\01foo". That is known to happen on ELF with the
     // tricks normally used for producing aliases (PR9177). Fortunately the
     // llvm mangler on ELF is a nop, so we can just avoid adding the \01
     // marker.
     char GlobalPrefix =
         getASTContext().getTargetInfo().getDataLayout().getGlobalPrefix();
     if (GlobalPrefix)
       Out << '\01'; // LLVM IR Marker for __asm("foo")

     Out << ALA->getLabel();
     return;
   }

   if (auto *GD = dyn_cast<MSGuidDecl>(D))
     return mangleMSGuidDecl(GD, Out);

   const ASTContext &ASTContext = getASTContext();
   CCMangling CC = getCallingConvMangling(ASTContext, D);

   if (CC == CCM_WasmMainArgcArgv) {
     Out << "__main_argc_argv";
     return;
   }

   bool MCXX = shouldMangleCXXName(D);
   const TargetInfo &TI = Context.getTargetInfo();
   if (CC == CCM_Other || (MCXX && TI.getCXXABI() == TargetCXXABI::Microsoft)) {
     if (const ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(D))
       mangleObjCMethodName(OMD, Out);
     else
       mangleCXXName(GD, Out);
     return;
   }

   Out << '\01';
   if (CC == CCM_Std)
     Out << '_';
   else if (CC == CCM_Fast)
     Out << '@';
   else if (CC == CCM_RegCall)
     Out << "__regcall3__";

   if (!MCXX)
     Out << D->getIdentifier()->getName();
   else if (const ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(D))
     mangleObjCMethodName(OMD, Out);
   else
     mangleCXXName(GD, Out);

   const FunctionDecl *FD = cast<FunctionDecl>(D);
   const FunctionType *FT = FD->getType()->castAs<FunctionType>();
   const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT);
   if (CC == CCM_Vector)
     Out << '@';
   Out << '@';
   if (!Proto) {
     Out << '0';
     return;
   }
   assert(!Proto->isVariadic());
   unsigned ArgWords = 0;
   if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD))
     if (!MD->isStatic())
       ++ArgWords;
   for (const auto &AT : Proto->param_types())
     // Size should be aligned to pointer size.
     ArgWords +=
         llvm::alignTo(ASTContext.getTypeSize(AT), TI.getPointerWidth(0)) /
         TI.getPointerWidth(0);
   Out << ((TI.getPointerWidth(0) / 8) * ArgWords);
 }

 void MangleContext::mangleMSGuidDecl(const MSGuidDecl *GD, raw_ostream &Out) {
   // For now, follow the MSVC naming convention for GUID objects on all
   // targets.
   MSGuidDecl::Parts P = GD->getParts();
   Out << llvm::format("_GUID_%08" PRIx32 "_%04" PRIx32 "_%04" PRIx32 "_",
                       P.Part1, P.Part2, P.Part3);
   unsigned I = 0;
   for (uint8_t C : P.Part4And5) {
     Out << llvm::format("%02" PRIx8, C);
     if (++I == 2)
       Out << "_";
   }
 }

 void MangleContext::mangleGlobalBlock(const BlockDecl *BD,
                                       const NamedDecl *ID,
                                       raw_ostream &Out) {
   unsigned discriminator = getBlockId(BD, false);
   if (ID) {
     if (shouldMangleDeclName(ID))
       mangleName(ID, Out);
     else {
       Out << ID->getIdentifier()->getName();
     }
   }
   if (discriminator == 0)
     Out << "_block_invoke";
   else
     Out << "_block_invoke_" << discriminator+1;
 }

 void MangleContext::mangleCtorBlock(const CXXConstructorDecl *CD,
                                     CXXCtorType CT, const BlockDecl *BD,
                                     raw_ostream &ResStream) {
   SmallString<64> Buffer;
   llvm::raw_svector_ostream Out(Buffer);
   mangleName(GlobalDecl(CD, CT), Out);
   mangleFunctionBlock(*this, Buffer, BD, ResStream);
 }

 void MangleContext::mangleDtorBlock(const CXXDestructorDecl *DD,
                                     CXXDtorType DT, const BlockDecl *BD,
                                     raw_ostream &ResStream) {
   SmallString<64> Buffer;
   llvm::raw_svector_ostream Out(Buffer);
   mangleName(GlobalDecl(DD, DT), Out);
   mangleFunctionBlock(*this, Buffer, BD, ResStream);
 }

 void MangleContext::mangleBlock(const DeclContext *DC, const BlockDecl *BD,
                                 raw_ostream &Out) {
   assert(!isa<CXXConstructorDecl>(DC) && !isa<CXXDestructorDecl>(DC));

   SmallString<64> Buffer;
   llvm::raw_svector_ostream Stream(Buffer);
   if (const ObjCMethodDecl *Method = dyn_cast<ObjCMethodDecl>(DC)) {
     mangleObjCMethodName(Method, Stream);
   } else {
     assert((isa<NamedDecl>(DC) || isa<BlockDecl>(DC)) &&
            "expected a NamedDecl or BlockDecl");
     if (isa<BlockDecl>(DC))
       for (; DC && isa<BlockDecl>(DC); DC = DC->getParent())
         (void) getBlockId(cast<BlockDecl>(DC), true);
     assert((isa<TranslationUnitDecl>(DC) || isa<NamedDecl>(DC)) &&
            "expected a TranslationUnitDecl or a NamedDecl");
     if (const auto *CD = dyn_cast<CXXConstructorDecl>(DC))
       mangleCtorBlock(CD, /*CT*/ Ctor_Complete, BD, Out);
     else if (const auto *DD = dyn_cast<CXXDestructorDecl>(DC))
       mangleDtorBlock(DD, /*DT*/ Dtor_Complete, BD, Out);
     else if (auto ND = dyn_cast<NamedDecl>(DC)) {
       if (!shouldMangleDeclName(ND) && ND->getIdentifier())
         Stream << ND->getIdentifier()->getName();
       else {
         // FIXME: We were doing a mangleUnqualifiedName() before, but that's
         // a private member of a class that will soon itself be private to the
         // Itanium C++ ABI object. What should we do now? Right now, I'm just
         // calling the mangleName() method on the MangleContext; is there a
         // better way?
         mangleName(ND, Stream);
       }
     }
   }
   mangleFunctionBlock(*this, Buffer, BD, Out);
 }

 void MangleContext::mangleObjCMethodNameWithoutSize(const ObjCMethodDecl *MD,
                                                     raw_ostream &OS) {
   const ObjCContainerDecl *CD =
   dyn_cast<ObjCContainerDecl>(MD->getDeclContext());
   assert (CD && "Missing container decl in GetNameForMethod");
   OS << (MD->isInstanceMethod() ? '-' : '+') << '[';
   if (const ObjCCategoryImplDecl *CID = dyn_cast<ObjCCategoryImplDecl>(CD)) {
     OS << CID->getClassInterface()->getName();
     OS << '(' << *CID << ')';
   } else {
     OS << CD->getName();
   }
   OS << ' ';
   MD->getSelector().print(OS);
   OS << ']';
 }

 void MangleContext::mangleObjCMethodName(const ObjCMethodDecl *MD,
                                          raw_ostream &Out) {
   SmallString<64> Name;
   llvm::raw_svector_ostream OS(Name);

   mangleObjCMethodNameWithoutSize(MD, OS);
   Out << OS.str().size() << OS.str();
 }

 class ASTNameGenerator::Implementation {
   std::unique_ptr<MangleContext> MC;
   llvm::DataLayout DL;

 public:
   explicit Implementation(ASTContext &Ctx)
       : MC(Ctx.createMangleContext()), DL(Ctx.getTargetInfo().getDataLayout()) {
   }

   bool writeName(const Decl *D, raw_ostream &OS) {
     // First apply frontend mangling.
     SmallString<128> FrontendBuf;
     llvm::raw_svector_ostream FrontendBufOS(FrontendBuf);
     if (auto *FD = dyn_cast<FunctionDecl>(D)) {
       if (FD->isDependentContext())
         return true;
       if (writeFuncOrVarName(FD, FrontendBufOS))
         return true;
     } else if (auto *VD = dyn_cast<VarDecl>(D)) {
       if (writeFuncOrVarName(VD, FrontendBufOS))
         return true;
     } else if (auto *MD = dyn_cast<ObjCMethodDecl>(D)) {
       MC->mangleObjCMethodNameWithoutSize(MD, OS);
       return false;
     } else if (auto *ID = dyn_cast<ObjCInterfaceDecl>(D)) {
       writeObjCClassName(ID, FrontendBufOS);
     } else {
       return true;
     }

     // Now apply backend mangling.
     llvm::Mangler::getNameWithPrefix(OS, FrontendBufOS.str(), DL);
     return false;
   }

   std::string getName(const Decl *D) {
     std::string Name;
     {
       llvm::raw_string_ostream OS(Name);
       writeName(D, OS);
     }
     return Name;
   }

   enum ObjCKind {
     ObjCClass,
     ObjCMetaclass,
   };

   static StringRef getClassSymbolPrefix(ObjCKind Kind,
                                         const ASTContext &Context) {
     if (Context.getLangOpts().ObjCRuntime.isGNUFamily())
       return Kind == ObjCMetaclass ? "_OBJC_METACLASS_" : "_OBJC_CLASS_";
     return Kind == ObjCMetaclass ? "OBJC_METACLASS_$_" : "OBJC_CLASS_$_";
   }

   std::vector<std::string> getAllManglings(const ObjCContainerDecl *OCD) {
     StringRef ClassName;
     if (const auto *OID = dyn_cast<ObjCInterfaceDecl>(OCD))
       ClassName = OID->getObjCRuntimeNameAsString();
     else if (const auto *OID = dyn_cast<ObjCImplementationDecl>(OCD))
       ClassName = OID->getObjCRuntimeNameAsString();

     if (ClassName.empty())
       return {};

     auto Mangle = [&](ObjCKind Kind, StringRef ClassName) -> std::string {
       SmallString<40> Mangled;
       auto Prefix = getClassSymbolPrefix(Kind, OCD->getASTContext());
       llvm::Mangler::getNameWithPrefix(Mangled, Prefix + ClassName, DL);
       return std::string(Mangled.str());
     };

     return {
         Mangle(ObjCClass, ClassName),
         Mangle(ObjCMetaclass, ClassName),
     };
   }

   std::vector<std::string> getAllManglings(const Decl *D) {
     if (const auto *OCD = dyn_cast<ObjCContainerDecl>(D))
       return getAllManglings(OCD);

     if (!(isa<CXXRecordDecl>(D) || isa<CXXMethodDecl>(D)))
       return {};

     const NamedDecl *ND = cast<NamedDecl>(D);

     ASTContext &Ctx = ND->getASTContext();
     std::unique_ptr<MangleContext> M(Ctx.createMangleContext());

     std::vector<std::string> Manglings;

     auto hasDefaultCXXMethodCC = [](ASTContext &C, const CXXMethodDecl *MD) {
       auto DefaultCC = C.getDefaultCallingConvention(/*IsVariadic=*/false,
                                                      /*IsCXXMethod=*/true);
       auto CC = MD->getType()->castAs<FunctionProtoType>()->getCallConv();
       return CC == DefaultCC;
     };

     if (const auto *CD = dyn_cast_or_null<CXXConstructorDecl>(ND)) {
       Manglings.emplace_back(getMangledStructor(CD, Ctor_Base));

       if (Ctx.getTargetInfo().getCXXABI().isItaniumFamily())
         if (!CD->getParent()->isAbstract())
           Manglings.emplace_back(getMangledStructor(CD, Ctor_Complete));

       if (Ctx.getTargetInfo().getCXXABI().isMicrosoft())
         if (CD->hasAttr<DLLExportAttr>() && CD->isDefaultConstructor())
           if (!(hasDefaultCXXMethodCC(Ctx, CD) && CD->getNumParams() == 0))
             Manglings.emplace_back(getMangledStructor(CD, Ctor_DefaultClosure));
     } else if (const auto *DD = dyn_cast_or_null<CXXDestructorDecl>(ND)) {
       Manglings.emplace_back(getMangledStructor(DD, Dtor_Base));
       if (Ctx.getTargetInfo().getCXXABI().isItaniumFamily()) {
         Manglings.emplace_back(getMangledStructor(DD, Dtor_Complete));
         if (DD->isVirtual())
           Manglings.emplace_back(getMangledStructor(DD, Dtor_Deleting));
       }
     } else if (const auto *MD = dyn_cast_or_null<CXXMethodDecl>(ND)) {
       Manglings.emplace_back(getName(ND));
       if (MD->isVirtual())
         if (const auto *TIV = Ctx.getVTableContext()->getThunkInfo(MD))
           for (const auto &T : *TIV)
             Manglings.emplace_back(getMangledThunk(MD, T));
     }

     return Manglings;
   }

 private:
   bool writeFuncOrVarName(const NamedDecl *D, raw_ostream &OS) {
     if (MC->shouldMangleDeclName(D)) {
       GlobalDecl GD;
       if (const auto *CtorD = dyn_cast<CXXConstructorDecl>(D))
         GD = GlobalDecl(CtorD, Ctor_Complete);
       else if (const auto *DtorD = dyn_cast<CXXDestructorDecl>(D))
         GD = GlobalDecl(DtorD, Dtor_Complete);
       else if (D->hasAttr<CUDAGlobalAttr>())
         GD = GlobalDecl(cast<FunctionDecl>(D));
       else
         GD = GlobalDecl(D);
       MC->mangleName(GD, OS);
       return false;
     } else {
       IdentifierInfo *II = D->getIdentifier();
       if (!II)
         return true;
       OS << II->getName();
       return false;
     }
   }

   void writeObjCClassName(const ObjCInterfaceDecl *D, raw_ostream &OS) {
     OS << getClassSymbolPrefix(ObjCClass, D->getASTContext());
     OS << D->getObjCRuntimeNameAsString();
   }

   std::string getMangledStructor(const NamedDecl *ND, unsigned StructorType) {
     std::string FrontendBuf;
     llvm::raw_string_ostream FOS(FrontendBuf);

     GlobalDecl GD;
     if (const auto *CD = dyn_cast_or_null<CXXConstructorDecl>(ND))
       GD = GlobalDecl(CD, static_cast<CXXCtorType>(StructorType));
     else if (const auto *DD = dyn_cast_or_null<CXXDestructorDecl>(ND))
       GD = GlobalDecl(DD, static_cast<CXXDtorType>(StructorType));
     MC->mangleName(GD, FOS);

     std::string BackendBuf;
     llvm::raw_string_ostream BOS(BackendBuf);

     llvm::Mangler::getNameWithPrefix(BOS, FOS.str(), DL);

     return BOS.str();
   }

   std::string getMangledThunk(const CXXMethodDecl *MD, const ThunkInfo &T) {
     std::string FrontendBuf;
     llvm::raw_string_ostream FOS(FrontendBuf);

     MC->mangleThunk(MD, T, FOS);

     std::string BackendBuf;
     llvm::raw_string_ostream BOS(BackendBuf);

     llvm::Mangler::getNameWithPrefix(BOS, FOS.str(), DL);

     return BOS.str();
   }
 };

 ASTNameGenerator::ASTNameGenerator(ASTContext &Ctx)
     : Impl(std::make_unique<Implementation>(Ctx)) {}

 ASTNameGenerator::~ASTNameGenerator() {}

 bool ASTNameGenerator::writeName(const Decl *D, raw_ostream &OS) {
   return Impl->writeName(D, OS);
 }

 std::string ASTNameGenerator::getName(const Decl *D) {
   return Impl->getName(D);
 }

 std::vector<std::string> ASTNameGenerator::getAllManglings(const Decl *D) {
   return Impl->getAllManglings(D);
 }
	//===--- Mangle.cpp - Mangle C++ Names --------------------------- C++ --===//
	//
	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
	// See https://llvm.org/LICENSE.txt for license information.
	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
	//
	//===----------------------------------------------------------------------===//
	//
	// Implements generic name mangling support for blocks and Objective-C.
	//
	//===----------------------------------------------------------------------===//
	#include "clang/AST/Attr.h"
	#include "clang/AST/ASTContext.h"
	#include "clang/AST/Decl.h"
	#include "clang/AST/DeclCXX.h"
	#include "clang/AST/DeclObjC.h"
	#include "clang/AST/DeclTemplate.h"
	#include "clang/AST/ExprCXX.h"
	#include "clang/AST/Mangle.h"
	#include "clang/AST/VTableBuilder.h"
	#include "clang/Basic/ABI.h"
	#include "clang/Basic/SourceManager.h"
	#include "clang/Basic/TargetInfo.h"
	#include "llvm/ADT/StringExtras.h"
	#include "llvm/IR/DataLayout.h"
	#include "llvm/IR/Mangler.h"
	#include "llvm/Support/ErrorHandling.h"
	#include "llvm/Support/raw_ostream.h"

	using namespace clang;

	// FIXME: For blocks we currently mimic GCC's mangling scheme, which leaves
	// much to be desired. Come up with a better mangling scheme.

	static void mangleFunctionBlock(MangleContext &Context,
	StringRef Outer,
	const BlockDecl *BD,
	raw_ostream &Out) {
	unsigned discriminator = Context.getBlockId(BD, true);
	if (discriminator == 0)
	Out << "__" << Outer << "_block_invoke";
	else
	Out << "__" << Outer << "_block_invoke_" << discriminator+1;
	}

	void MangleContext::anchor() { }

	enum CCMangling {
	CCM_Other,
	CCM_Fast,
	CCM_RegCall,
	CCM_Vector,
	CCM_Std,
	CCM_WasmMainArgcArgv
	};

	static bool isExternC(const NamedDecl *ND) {
	if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
	return FD->isExternC();
	if (const VarDecl *VD = dyn_cast<VarDecl>(ND))
	return VD->isExternC();
	return false;
	}

	static CCMangling getCallingConvMangling(const ASTContext &Context,
	const NamedDecl *ND) {
	const TargetInfo &TI = Context.getTargetInfo();
	const llvm::Triple &Triple = TI.getTriple();

	// On wasm, the argc/argv form of "main" is renamed so that the startup code
	// can call it with the correct function signature.
	// On Emscripten, users may be exporting "main" and expecting to call it
	// themselves, so we can't mangle it.
	if (Triple.isWasm() && !Triple.isOSEmscripten())
	if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
	if (FD->isMain() && FD->hasPrototype() && FD->param_size() == 2)
	return CCM_WasmMainArgcArgv;

	if (!Triple.isOSWindows() \|\| !Triple.isX86())
	return CCM_Other;

	if (Context.getLangOpts().CPlusPlus && !isExternC(ND) &&
	TI.getCXXABI() == TargetCXXABI::Microsoft)
	return CCM_Other;

	const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND);
	if (!FD)
	return CCM_Other;
	QualType T = FD->getType();

	const FunctionType *FT = T->castAs<FunctionType>();

	CallingConv CC = FT->getCallConv();
	switch (CC) {
	default:
	return CCM_Other;
	case CC_X86FastCall:
	return CCM_Fast;
	case CC_X86StdCall:
	return CCM_Std;
	case CC_X86VectorCall:
	return CCM_Vector;
	}
	}

	bool MangleContext::shouldMangleDeclName(const NamedDecl *D) {
	const ASTContext &ASTContext = getASTContext();

	CCMangling CC = getCallingConvMangling(ASTContext, D);
	if (CC != CCM_Other)
	return true;

	// If the declaration has an owning module for linkage purposes that needs to
	// be mangled, we must mangle its name.
	if (!D->hasExternalFormalLinkage() && D->getOwningModuleForLinkage())
	return true;

	// In C, functions with no attributes never need to be mangled. Fastpath them.
	if (!getASTContext().getLangOpts().CPlusPlus && !D->hasAttrs())
	return false;

	// Any decl can be declared with __asm("foo") on it, and this takes precedence
	// over all other naming in the .o file.
	if (D->hasAttr<AsmLabelAttr>())
	return true;

	// Declarations that don't have identifier names always need to be mangled.
	if (isa<MSGuidDecl>(D))
	return true;

	return shouldMangleCXXName(D);
	}

	void MangleContext::mangleName(GlobalDecl GD, raw_ostream &Out) {
	const NamedDecl *D = cast<NamedDecl>(GD.getDecl());
	// Any decl can be declared with __asm("foo") on it, and this takes precedence
	// over all other naming in the .o file.
	if (const AsmLabelAttr *ALA = D->getAttr<AsmLabelAttr>()) {
	// If we have an asm name, then we use it as the mangling.

	// If the label isn't literal, or if this is an alias for an LLVM intrinsic,
	// do not add a "\01" prefix.
	if (!ALA->getIsLiteralLabel() \|\| ALA->getLabel().startswith("llvm.")) {
	Out << ALA->getLabel();
	return;
	}

	// Adding the prefix can cause problems when one file has a "foo" and
	// another has a "\01foo". That is known to happen on ELF with the
	// tricks normally used for producing aliases (PR9177). Fortunately the
	// llvm mangler on ELF is a nop, so we can just avoid adding the \01
	// marker.
	char GlobalPrefix =
	getASTContext().getTargetInfo().getDataLayout().getGlobalPrefix();
	if (GlobalPrefix)
	Out << '\01'; // LLVM IR Marker for __asm("foo")

	Out << ALA->getLabel();
	return;
	}

	if (auto *GD = dyn_cast<MSGuidDecl>(D))
	return mangleMSGuidDecl(GD, Out);

	const ASTContext &ASTContext = getASTContext();
	CCMangling CC = getCallingConvMangling(ASTContext, D);

	if (CC == CCM_WasmMainArgcArgv) {
	Out << "__main_argc_argv";
	return;
	}

	bool MCXX = shouldMangleCXXName(D);
	const TargetInfo &TI = Context.getTargetInfo();
	if (CC == CCM_Other \|\| (MCXX && TI.getCXXABI() == TargetCXXABI::Microsoft)) {
	if (const ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(D))
	mangleObjCMethodName(OMD, Out);
	else
	mangleCXXName(GD, Out);
	return;
	}

	Out << '\01';
	if (CC == CCM_Std)
	Out << '_';
	else if (CC == CCM_Fast)
	Out << '@';
	else if (CC == CCM_RegCall)
	Out << "__regcall3__";

	if (!MCXX)
	Out << D->getIdentifier()->getName();
	else if (const ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(D))
	mangleObjCMethodName(OMD, Out);
	else
	mangleCXXName(GD, Out);

	const FunctionDecl *FD = cast<FunctionDecl>(D);
	const FunctionType *FT = FD->getType()->castAs<FunctionType>();
	const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT);
	if (CC == CCM_Vector)
	Out << '@';
	Out << '@';
	if (!Proto) {
	Out << '0';
	return;
	}
	assert(!Proto->isVariadic());
	unsigned ArgWords = 0;
	if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD))
	if (!MD->isStatic())
	++ArgWords;
	for (const auto &AT : Proto->param_types())
	// Size should be aligned to pointer size.
	ArgWords +=
	llvm::alignTo(ASTContext.getTypeSize(AT), TI.getPointerWidth(0)) /
	TI.getPointerWidth(0);
	Out << ((TI.getPointerWidth(0) / 8) * ArgWords);
	}

	void MangleContext::mangleMSGuidDecl(const MSGuidDecl *GD, raw_ostream &Out) {
	// For now, follow the MSVC naming convention for GUID objects on all
	// targets.
	MSGuidDecl::Parts P = GD->getParts();
	Out << llvm::format("_GUID_%08" PRIx32 "_%04" PRIx32 "_%04" PRIx32 "_",
	P.Part1, P.Part2, P.Part3);
	unsigned I = 0;
	for (uint8_t C : P.Part4And5) {
	Out << llvm::format("%02" PRIx8, C);
	if (++I == 2)
	Out << "_";
	}
	}

	void MangleContext::mangleGlobalBlock(const BlockDecl *BD,
	const NamedDecl *ID,
	raw_ostream &Out) {
	unsigned discriminator = getBlockId(BD, false);
	if (ID) {
	if (shouldMangleDeclName(ID))
	mangleName(ID, Out);
	else {
	Out << ID->getIdentifier()->getName();
	}
	}
	if (discriminator == 0)
	Out << "_block_invoke";
	else
	Out << "_block_invoke_" << discriminator+1;
	}

	void MangleContext::mangleCtorBlock(const CXXConstructorDecl *CD,
	CXXCtorType CT, const BlockDecl *BD,
	raw_ostream &ResStream) {
	SmallString<64> Buffer;
	llvm::raw_svector_ostream Out(Buffer);
	mangleName(GlobalDecl(CD, CT), Out);
	mangleFunctionBlock(*this, Buffer, BD, ResStream);
	}

	void MangleContext::mangleDtorBlock(const CXXDestructorDecl *DD,
	CXXDtorType DT, const BlockDecl *BD,
	raw_ostream &ResStream) {
	SmallString<64> Buffer;
	llvm::raw_svector_ostream Out(Buffer);
	mangleName(GlobalDecl(DD, DT), Out);
	mangleFunctionBlock(*this, Buffer, BD, ResStream);
	}

	void MangleContext::mangleBlock(const DeclContext DC, const BlockDecl BD,
	raw_ostream &Out) {
	assert(!isa<CXXConstructorDecl>(DC) && !isa<CXXDestructorDecl>(DC));

	SmallString<64> Buffer;
	llvm::raw_svector_ostream Stream(Buffer);
	if (const ObjCMethodDecl *Method = dyn_cast<ObjCMethodDecl>(DC)) {
	mangleObjCMethodName(Method, Stream);
	} else {
	assert((isa<NamedDecl>(DC) \|\| isa<BlockDecl>(DC)) &&
	"expected a NamedDecl or BlockDecl");
	if (isa<BlockDecl>(DC))
	for (; DC && isa<BlockDecl>(DC); DC = DC->getParent())
	(void) getBlockId(cast<BlockDecl>(DC), true);
	assert((isa<TranslationUnitDecl>(DC) \|\| isa<NamedDecl>(DC)) &&
	"expected a TranslationUnitDecl or a NamedDecl");
	if (const auto *CD = dyn_cast<CXXConstructorDecl>(DC))
	mangleCtorBlock(CD, /CT/ Ctor_Complete, BD, Out);
	else if (const auto *DD = dyn_cast<CXXDestructorDecl>(DC))
	mangleDtorBlock(DD, /DT/ Dtor_Complete, BD, Out);
	else if (auto ND = dyn_cast<NamedDecl>(DC)) {
	if (!shouldMangleDeclName(ND) && ND->getIdentifier())
	Stream << ND->getIdentifier()->getName();
	else {
	// FIXME: We were doing a mangleUnqualifiedName() before, but that's
	// a private member of a class that will soon itself be private to the
	// Itanium C++ ABI object. What should we do now? Right now, I'm just
	// calling the mangleName() method on the MangleContext; is there a
	// better way?
	mangleName(ND, Stream);
	}
	}
	}
	mangleFunctionBlock(*this, Buffer, BD, Out);
	}

	void MangleContext::mangleObjCMethodNameWithoutSize(const ObjCMethodDecl *MD,
	raw_ostream &OS) {
	const ObjCContainerDecl *CD =
	dyn_cast<ObjCContainerDecl>(MD->getDeclContext());
	assert (CD && "Missing container decl in GetNameForMethod");
	OS << (MD->isInstanceMethod() ? '-' : '+') << '[';
	if (const ObjCCategoryImplDecl *CID = dyn_cast<ObjCCategoryImplDecl>(CD)) {
	OS << CID->getClassInterface()->getName();
	OS << '(' << *CID << ')';
	} else {
	OS << CD->getName();
	}
	OS << ' ';
	MD->getSelector().print(OS);
	OS << ']';
	}

	void MangleContext::mangleObjCMethodName(const ObjCMethodDecl *MD,
	raw_ostream &Out) {
	SmallString<64> Name;
	llvm::raw_svector_ostream OS(Name);

	mangleObjCMethodNameWithoutSize(MD, OS);
	Out << OS.str().size() << OS.str();
	}

	class ASTNameGenerator::Implementation {
	std::unique_ptr<MangleContext> MC;
	llvm::DataLayout DL;

	public:
	explicit Implementation(ASTContext &Ctx)
	: MC(Ctx.createMangleContext()), DL(Ctx.getTargetInfo().getDataLayout()) {
	}

	bool writeName(const Decl *D, raw_ostream &OS) {
	// First apply frontend mangling.
	SmallString<128> FrontendBuf;
	llvm::raw_svector_ostream FrontendBufOS(FrontendBuf);
	if (auto *FD = dyn_cast<FunctionDecl>(D)) {
	if (FD->isDependentContext())
	return true;
	if (writeFuncOrVarName(FD, FrontendBufOS))
	return true;
	} else if (auto *VD = dyn_cast<VarDecl>(D)) {
	if (writeFuncOrVarName(VD, FrontendBufOS))
	return true;
	} else if (auto *MD = dyn_cast<ObjCMethodDecl>(D)) {
	MC->mangleObjCMethodNameWithoutSize(MD, OS);
	return false;
	} else if (auto *ID = dyn_cast<ObjCInterfaceDecl>(D)) {
	writeObjCClassName(ID, FrontendBufOS);
	} else {
	return true;
	}

	// Now apply backend mangling.
	llvm::Mangler::getNameWithPrefix(OS, FrontendBufOS.str(), DL);
	return false;
	}

	std::string getName(const Decl *D) {
	std::string Name;
	{
	llvm::raw_string_ostream OS(Name);
	writeName(D, OS);
	}
	return Name;
	}

	enum ObjCKind {
	ObjCClass,
	ObjCMetaclass,
	};

	static StringRef getClassSymbolPrefix(ObjCKind Kind,
	const ASTContext &Context) {
	if (Context.getLangOpts().ObjCRuntime.isGNUFamily())
	return Kind == ObjCMetaclass ? "_OBJC_METACLASS_" : "_OBJC_CLASS_";
	return Kind == ObjCMetaclass ? "OBJC_METACLASS_$_" : "OBJC_CLASS_$_";
	}

	std::vector<std::string> getAllManglings(const ObjCContainerDecl *OCD) {
	StringRef ClassName;
	if (const auto *OID = dyn_cast<ObjCInterfaceDecl>(OCD))
	ClassName = OID->getObjCRuntimeNameAsString();
	else if (const auto *OID = dyn_cast<ObjCImplementationDecl>(OCD))
	ClassName = OID->getObjCRuntimeNameAsString();

	if (ClassName.empty())
	return {};

	auto Mangle = [&](ObjCKind Kind, StringRef ClassName) -> std::string {
	SmallString<40> Mangled;
	auto Prefix = getClassSymbolPrefix(Kind, OCD->getASTContext());
	llvm::Mangler::getNameWithPrefix(Mangled, Prefix + ClassName, DL);
	return std::string(Mangled.str());
	};

	return {
	Mangle(ObjCClass, ClassName),
	Mangle(ObjCMetaclass, ClassName),
	};
	}

	std::vector<std::string> getAllManglings(const Decl *D) {
	if (const auto *OCD = dyn_cast<ObjCContainerDecl>(D))
	return getAllManglings(OCD);

	if (!(isa<CXXRecordDecl>(D) \|\| isa<CXXMethodDecl>(D)))
	return {};

	const NamedDecl *ND = cast<NamedDecl>(D);

	ASTContext &Ctx = ND->getASTContext();
	std::unique_ptr<MangleContext> M(Ctx.createMangleContext());

	std::vector<std::string> Manglings;

	auto hasDefaultCXXMethodCC = [](ASTContext &C, const CXXMethodDecl *MD) {
	auto DefaultCC = C.getDefaultCallingConvention(/IsVariadic=/false,
	/IsCXXMethod=/true);
	auto CC = MD->getType()->castAs<FunctionProtoType>()->getCallConv();
	return CC == DefaultCC;
	};

	if (const auto *CD = dyn_cast_or_null<CXXConstructorDecl>(ND)) {
	Manglings.emplace_back(getMangledStructor(CD, Ctor_Base));

	if (Ctx.getTargetInfo().getCXXABI().isItaniumFamily())
	if (!CD->getParent()->isAbstract())
	Manglings.emplace_back(getMangledStructor(CD, Ctor_Complete));

	if (Ctx.getTargetInfo().getCXXABI().isMicrosoft())
	if (CD->hasAttr<DLLExportAttr>() && CD->isDefaultConstructor())
	if (!(hasDefaultCXXMethodCC(Ctx, CD) && CD->getNumParams() == 0))
	Manglings.emplace_back(getMangledStructor(CD, Ctor_DefaultClosure));
	} else if (const auto *DD = dyn_cast_or_null<CXXDestructorDecl>(ND)) {
	Manglings.emplace_back(getMangledStructor(DD, Dtor_Base));
	if (Ctx.getTargetInfo().getCXXABI().isItaniumFamily()) {
	Manglings.emplace_back(getMangledStructor(DD, Dtor_Complete));
	if (DD->isVirtual())
	Manglings.emplace_back(getMangledStructor(DD, Dtor_Deleting));
	}
	} else if (const auto *MD = dyn_cast_or_null<CXXMethodDecl>(ND)) {
	Manglings.emplace_back(getName(ND));
	if (MD->isVirtual())
	if (const auto *TIV = Ctx.getVTableContext()->getThunkInfo(MD))
	for (const auto &T : *TIV)
	Manglings.emplace_back(getMangledThunk(MD, T));
	}

	return Manglings;
	}

	private:
	bool writeFuncOrVarName(const NamedDecl *D, raw_ostream &OS) {
	if (MC->shouldMangleDeclName(D)) {
	GlobalDecl GD;
	if (const auto *CtorD = dyn_cast<CXXConstructorDecl>(D))
	GD = GlobalDecl(CtorD, Ctor_Complete);
	else if (const auto *DtorD = dyn_cast<CXXDestructorDecl>(D))
	GD = GlobalDecl(DtorD, Dtor_Complete);
	else if (D->hasAttr<CUDAGlobalAttr>())
	GD = GlobalDecl(cast<FunctionDecl>(D));
	else
	GD = GlobalDecl(D);
	MC->mangleName(GD, OS);
	return false;
	} else {
	IdentifierInfo *II = D->getIdentifier();
	if (!II)
	return true;
	OS << II->getName();
	return false;
	}
	}

	void writeObjCClassName(const ObjCInterfaceDecl *D, raw_ostream &OS) {
	OS << getClassSymbolPrefix(ObjCClass, D->getASTContext());
	OS << D->getObjCRuntimeNameAsString();
	}

	std::string getMangledStructor(const NamedDecl *ND, unsigned StructorType) {
	std::string FrontendBuf;
	llvm::raw_string_ostream FOS(FrontendBuf);

	GlobalDecl GD;
	if (const auto *CD = dyn_cast_or_null<CXXConstructorDecl>(ND))
	GD = GlobalDecl(CD, static_cast<CXXCtorType>(StructorType));
	else if (const auto *DD = dyn_cast_or_null<CXXDestructorDecl>(ND))
	GD = GlobalDecl(DD, static_cast<CXXDtorType>(StructorType));
	MC->mangleName(GD, FOS);

	std::string BackendBuf;
	llvm::raw_string_ostream BOS(BackendBuf);

	llvm::Mangler::getNameWithPrefix(BOS, FOS.str(), DL);

	return BOS.str();
	}

	std::string getMangledThunk(const CXXMethodDecl *MD, const ThunkInfo &T) {
	std::string FrontendBuf;
	llvm::raw_string_ostream FOS(FrontendBuf);

	MC->mangleThunk(MD, T, FOS);

	std::string BackendBuf;
	llvm::raw_string_ostream BOS(BackendBuf);

	llvm::Mangler::getNameWithPrefix(BOS, FOS.str(), DL);

	return BOS.str();
	}
	};

	ASTNameGenerator::ASTNameGenerator(ASTContext &Ctx)
	: Impl(std::make_unique<Implementation>(Ctx)) {}

	ASTNameGenerator::~ASTNameGenerator() {}

	bool ASTNameGenerator::writeName(const Decl *D, raw_ostream &OS) {
	return Impl->writeName(D, OS);
	}

	std::string ASTNameGenerator::getName(const Decl *D) {
	return Impl->getName(D);
	}

	std::vector<std::string> ASTNameGenerator::getAllManglings(const Decl *D) {
	return Impl->getAllManglings(D);
	}