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//===-- Mangler.cpp - Self-contained c/asm llvm name mangler --------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Unified name mangler for assembly backends.
//
//===----------------------------------------------------------------------===//
#include "llvm/IR/Mangler.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Twine.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/TargetParser/Triple.h"
using namespace llvm;
namespace {
enum ManglerPrefixTy {
Default, ///< Emit default string before each symbol.
Private, ///< Emit "private" prefix before each symbol.
LinkerPrivate ///< Emit "linker private" prefix before each symbol.
};
}
static void getNameWithPrefixImpl(raw_ostream &OS, const Twine &GVName,
ManglerPrefixTy PrefixTy,
const DataLayout &DL, char Prefix) {
SmallString<256> TmpData;
StringRef Name = GVName.toStringRef(TmpData);
assert(!Name.empty() && "getNameWithPrefix requires non-empty name");
// No need to do anything special if the global has the special "do not
// mangle" flag in the name.
if (Name[0] == '\1') {
OS << Name.substr(1);
return;
}
if (DL.doNotMangleLeadingQuestionMark() && Name[0] == '?')
Prefix = '\0';
if (PrefixTy == Private)
OS << DL.getPrivateGlobalPrefix();
else if (PrefixTy == LinkerPrivate)
OS << DL.getLinkerPrivateGlobalPrefix();
if (Prefix != '\0')
OS << Prefix;
// If this is a simple string that doesn't need escaping, just append it.
OS << Name;
}
static void getNameWithPrefixImpl(raw_ostream &OS, const Twine &GVName,
const DataLayout &DL,
ManglerPrefixTy PrefixTy) {
char Prefix = DL.getGlobalPrefix();
return getNameWithPrefixImpl(OS, GVName, PrefixTy, DL, Prefix);
}
void Mangler::getNameWithPrefix(raw_ostream &OS, const Twine &GVName,
const DataLayout &DL) {
return getNameWithPrefixImpl(OS, GVName, DL, Default);
}
void Mangler::getNameWithPrefix(SmallVectorImpl<char> &OutName,
const Twine &GVName, const DataLayout &DL) {
raw_svector_ostream OS(OutName);
char Prefix = DL.getGlobalPrefix();
return getNameWithPrefixImpl(OS, GVName, Default, DL, Prefix);
}
static bool hasByteCountSuffix(CallingConv::ID CC) {
switch (CC) {
case CallingConv::X86_FastCall:
case CallingConv::X86_StdCall:
case CallingConv::X86_VectorCall:
return true;
default:
return false;
}
}
/// Microsoft fastcall and stdcall functions require a suffix on their name
/// indicating the number of words of arguments they take.
static void addByteCountSuffix(raw_ostream &OS, const Function *F,
const DataLayout &DL) {
// Calculate arguments size total.
unsigned ArgWords = 0;
const unsigned PtrSize = DL.getPointerSize();
for (const Argument &A : F->args()) {
// For the purposes of the byte count suffix, structs returned by pointer
// do not count as function arguments.
if (A.hasStructRetAttr())
continue;
// 'Dereference' type in case of byval or inalloca parameter attribute.
uint64_t AllocSize = A.hasPassPointeeByValueCopyAttr() ?
A.getPassPointeeByValueCopySize(DL) :
DL.getTypeAllocSize(A.getType());
// Size should be aligned to pointer size.
ArgWords += alignTo(AllocSize, PtrSize);
}
OS << '@' << ArgWords;
}
void Mangler::getNameWithPrefix(raw_ostream &OS, const GlobalValue *GV,
bool CannotUsePrivateLabel) const {
ManglerPrefixTy PrefixTy = Default;
assert(GV != nullptr && "Invalid Global Value");
if (GV->hasPrivateLinkage()) {
if (CannotUsePrivateLabel)
PrefixTy = LinkerPrivate;
else
PrefixTy = Private;
}
const DataLayout &DL = GV->getParent()->getDataLayout();
if (!GV->hasName()) {
// Get the ID for the global, assigning a new one if we haven't got one
// already.
unsigned &ID = AnonGlobalIDs[GV];
if (ID == 0)
ID = AnonGlobalIDs.size();
// Must mangle the global into a unique ID.
getNameWithPrefixImpl(OS, "__unnamed_" + Twine(ID), DL, PrefixTy);
return;
}
StringRef Name = GV->getName();
char Prefix = DL.getGlobalPrefix();
// Mangle functions with Microsoft calling conventions specially. Only do
// this mangling for x86_64 vectorcall and 32-bit x86.
const Function *MSFunc = dyn_cast_or_null<Function>(GV->getAliaseeObject());
// Don't add byte count suffixes when '\01' or '?' are in the first
// character.
if (Name.starts_with("\01") ||
(DL.doNotMangleLeadingQuestionMark() && Name.starts_with("?")))
MSFunc = nullptr;
CallingConv::ID CC =
MSFunc ? MSFunc->getCallingConv() : (unsigned)CallingConv::C;
if (!DL.hasMicrosoftFastStdCallMangling() &&
CC != CallingConv::X86_VectorCall)
MSFunc = nullptr;
if (MSFunc) {
if (CC == CallingConv::X86_FastCall)
Prefix = '@'; // fastcall functions have an @ prefix instead of _.
else if (CC == CallingConv::X86_VectorCall)
Prefix = '\0'; // vectorcall functions have no prefix.
}
getNameWithPrefixImpl(OS, Name, PrefixTy, DL, Prefix);
if (!MSFunc)
return;
// If we are supposed to add a microsoft-style suffix for stdcall, fastcall,
// or vectorcall, add it. These functions have a suffix of @N where N is the
// cumulative byte size of all of the parameters to the function in decimal.
if (CC == CallingConv::X86_VectorCall)
OS << '@'; // vectorcall functions use a double @ suffix.
FunctionType *FT = MSFunc->getFunctionType();
if (hasByteCountSuffix(CC) &&
// "Pure" variadic functions do not receive @0 suffix.
(!FT->isVarArg() || FT->getNumParams() == 0 ||
(FT->getNumParams() == 1 && MSFunc->hasStructRetAttr())))
addByteCountSuffix(OS, MSFunc, DL);
}
void Mangler::getNameWithPrefix(SmallVectorImpl<char> &OutName,
const GlobalValue *GV,
bool CannotUsePrivateLabel) const {
raw_svector_ostream OS(OutName);
getNameWithPrefix(OS, GV, CannotUsePrivateLabel);
}
// Check if the name needs quotes to be safe for the linker to interpret.
static bool canBeUnquotedInDirective(char C) {
return isAlnum(C) || C == '_' || C == '@' || C == '#';
}
static bool canBeUnquotedInDirective(StringRef Name) {
if (Name.empty())
return false;
// If any of the characters in the string is an unacceptable character, force
// quotes.
for (char C : Name) {
if (!canBeUnquotedInDirective(C))
return false;
}
return true;
}
void llvm::emitLinkerFlagsForGlobalCOFF(raw_ostream &OS, const GlobalValue *GV,
const Triple &TT, Mangler &Mangler) {
if (GV->hasDLLExportStorageClass() && !GV->isDeclaration()) {
if (TT.isWindowsMSVCEnvironment())
OS << " /EXPORT:";
else
OS << " -export:";
bool NeedQuotes = GV->hasName() && !canBeUnquotedInDirective(GV->getName());
if (NeedQuotes)
OS << "\"";
if (TT.isWindowsGNUEnvironment() || TT.isWindowsCygwinEnvironment()) {
std::string Flag;
raw_string_ostream FlagOS(Flag);
Mangler.getNameWithPrefix(FlagOS, GV, false);
FlagOS.flush();
if (Flag[0] == GV->getParent()->getDataLayout().getGlobalPrefix())
OS << Flag.substr(1);
else
OS << Flag;
} else {
Mangler.getNameWithPrefix(OS, GV, false);
}
if (TT.isWindowsArm64EC()) {
// Use EXPORTAS for mangled ARM64EC symbols.
// FIXME: During LTO, we're invoked prior to the EC lowering pass,
// so symbols are not yet mangled. Emitting the unmangled name
// typically functions correctly; the linker can resolve the export
// with the demangled alias.
if (std::optional<std::string> demangledName =
getArm64ECDemangledFunctionName(GV->getName()))
OS << ",EXPORTAS," << *demangledName;
}
if (NeedQuotes)
OS << "\"";
if (!GV->getValueType()->isFunctionTy()) {
if (TT.isWindowsMSVCEnvironment())
OS << ",DATA";
else
OS << ",data";
}
}
if (GV->hasHiddenVisibility() && !GV->isDeclaration() && TT.isOSCygMing()) {
OS << " -exclude-symbols:";
bool NeedQuotes = GV->hasName() && !canBeUnquotedInDirective(GV->getName());
if (NeedQuotes)
OS << "\"";
std::string Flag;
raw_string_ostream FlagOS(Flag);
Mangler.getNameWithPrefix(FlagOS, GV, false);
FlagOS.flush();
if (Flag[0] == GV->getParent()->getDataLayout().getGlobalPrefix())
OS << Flag.substr(1);
else
OS << Flag;
if (NeedQuotes)
OS << "\"";
}
}
void llvm::emitLinkerFlagsForUsedCOFF(raw_ostream &OS, const GlobalValue *GV,
const Triple &T, Mangler &M) {
if (!T.isWindowsMSVCEnvironment())
return;
OS << " /INCLUDE:";
bool NeedQuotes = GV->hasName() && !canBeUnquotedInDirective(GV->getName());
if (NeedQuotes)
OS << "\"";
M.getNameWithPrefix(OS, GV, false);
if (NeedQuotes)
OS << "\"";
}
std::optional<std::string> llvm::getArm64ECMangledFunctionName(StringRef Name) {
bool IsCppFn = Name[0] == '?';
if (IsCppFn && Name.find("$$h") != std::string::npos)
return std::nullopt;
if (!IsCppFn && Name[0] == '#')
return std::nullopt;
StringRef Prefix = "$$h";
size_t InsertIdx = 0;
if (IsCppFn) {
InsertIdx = Name.find("@@");
size_t ThreeAtSignsIdx = Name.find("@@@");
if (InsertIdx != std::string::npos && InsertIdx != ThreeAtSignsIdx) {
InsertIdx += 2;
} else {
InsertIdx = Name.find("@");
if (InsertIdx != std::string::npos)
InsertIdx++;
}
} else {
Prefix = "#";
}
return std::optional<std::string>(
(Name.substr(0, InsertIdx) + Prefix + Name.substr(InsertIdx)).str());
}
std::optional<std::string>
llvm::getArm64ECDemangledFunctionName(StringRef Name) {
if (Name[0] == '#')
return std::optional<std::string>(Name.substr(1));
if (Name[0] != '?')
return std::nullopt;
std::pair<StringRef, StringRef> Pair = Name.split("$$h");
if (Pair.second.empty())
return std::nullopt;
return std::optional<std::string>((Pair.first + Pair.second).str());
}