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llvm-project/clang/lib/AST/Mangle.cpp

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//===--- 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/Format.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;
// C functions with internal linkage have to be mangled with option
// -funique-internal-linkage-names.
if (!getASTContext().getLangOpts().CPlusPlus &&
isUniqueInternalLinkageDecl(D))
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 ASTContext &ASTContext = getASTContext();
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.
StringRef UserLabelPrefix =
getASTContext().getTargetInfo().getUserLabelPrefix();
#ifndef NDEBUG
char GlobalPrefix =
llvm::DataLayout(getASTContext().getTargetInfo().getDataLayoutString())
.getGlobalPrefix();
assert((UserLabelPrefix.empty() && !GlobalPrefix) ||
(UserLabelPrefix.size() == 1 && UserLabelPrefix[0] == GlobalPrefix));
#endif
if (!UserLabelPrefix.empty())
Out << '\01'; // LLVM IR Marker for __asm("foo")
Out << ALA->getLabel();
return;
}
if (auto *GD = dyn_cast<MSGuidDecl>(D))
return mangleMSGuidDecl(GD, Out);
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))
mangleObjCMethodNameAsSourceName(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))
mangleObjCMethodNameAsSourceName(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)) {
mangleObjCMethodNameAsSourceName(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::mangleObjCMethodName(const ObjCMethodDecl *MD,
raw_ostream &OS,
bool includePrefixByte,
bool includeCategoryNamespace) {
if (getASTContext().getLangOpts().ObjCRuntime.isGNUFamily()) {
// This is the mangling we've always used on the GNU runtimes, but it
// has obvious collisions in the face of underscores within class
// names, category names, and selectors; maybe we should improve it.
OS << (MD->isClassMethod() ? "_c_" : "_i_")
<< MD->getClassInterface()->getName() << '_';
if (includeCategoryNamespace) {
if (auto category = MD->getCategory())
OS << category->getName();
}
OS << '_';
auto selector = MD->getSelector();
for (unsigned slotIndex = 0,
numArgs = selector.getNumArgs(),
slotEnd = std::max(numArgs, 1U);
slotIndex != slotEnd; ++slotIndex) {
if (auto name = selector.getIdentifierInfoForSlot(slotIndex))
OS << name->getName();
// Replace all the positions that would've been ':' with '_'.
// That's after each slot except that a unary selector doesn't
// end in ':'.
if (numArgs)
OS << '_';
}
return;
}
// \01+[ContainerName(CategoryName) SelectorName]
if (includePrefixByte) {
OS << '\01';
}
OS << (MD->isInstanceMethod() ? '-' : '+') << '[';
if (const auto *CID = MD->getCategory()) {
OS << CID->getClassInterface()->getName();
if (includeCategoryNamespace) {
OS << '(' << *CID << ')';
}
} else if (const auto *CD =
dyn_cast<ObjCContainerDecl>(MD->getDeclContext())) {
OS << CD->getName();
} else {
llvm_unreachable("Unexpected ObjC method decl context");
}
OS << ' ';
MD->getSelector().print(OS);
OS << ']';
}
void MangleContext::mangleObjCMethodNameAsSourceName(const ObjCMethodDecl *MD,
raw_ostream &Out) {
SmallString<64> Name;
llvm::raw_svector_ostream OS(Name);
mangleObjCMethodName(MD, OS, /*includePrefixByte=*/false,
/*includeCategoryNamespace=*/true);
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().getDataLayoutString()) {}
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->mangleObjCMethodName(MD, OS, /*includePrefixByte=*/false,
/*includeCategoryNamespace=*/true);
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);
}
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