llvm-project/llvm/lib/IR/Mangler.cpp

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//===-- Mangler.cpp - Self-contained c/asm llvm name mangler --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Unified name mangler for assembly backends.
//
//===----------------------------------------------------------------------===//
#include "llvm/IR/Mangler.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Twine.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
static void getNameWithPrefixx(raw_ostream &OS, const Twine &GVName,
Mangler::ManglerPrefixTy PrefixTy,
const DataLayout &DL, bool UseAt) {
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 (PrefixTy == Mangler::Private)
OS << DL.getPrivateGlobalPrefix();
else if (PrefixTy == Mangler::LinkerPrivate)
OS << DL.getLinkerPrivateGlobalPrefix();
if (UseAt) {
OS << '@';
} else {
char Prefix = DL.getGlobalPrefix();
if (Prefix != '\0')
OS << Prefix;
}
// If this is a simple string that doesn't need escaping, just append it.
OS << Name;
}
void Mangler::getNameWithPrefix(raw_ostream &OS, const Twine &GVName,
ManglerPrefixTy PrefixTy) const {
return getNameWithPrefixx(OS, GVName, PrefixTy, *DL, false);
}
void Mangler::getNameWithPrefix(SmallVectorImpl<char> &OutName,
const Twine &GVName,
ManglerPrefixTy PrefixTy) const {
raw_svector_ostream OS(OutName);
return getNameWithPrefix(OS, GVName, PrefixTy);
}
/// AddFastCallStdCallSuffix - Microsoft fastcall and stdcall functions require
/// a suffix on their name indicating the number of words of arguments they
/// take.
static void AddFastCallStdCallSuffix(raw_ostream &OS, const Function *F,
const DataLayout &TD) {
// Calculate arguments size total.
unsigned ArgWords = 0;
for (Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end();
AI != AE; ++AI) {
// Skip arguments in registers to handle typical fastcall lowering.
if (F->getAttributes().hasAttribute(AI->getArgNo() + 1, Attribute::InReg))
continue;
Type *Ty = AI->getType();
// 'Dereference' type in case of byval or inalloca parameter attribute.
if (AI->hasByValOrInAllocaAttr())
Ty = cast<PointerType>(Ty)->getElementType();
// Size should be aligned to DWORD boundary
ArgWords += ((TD.getTypeAllocSize(Ty) + 3)/4)*4;
}
OS << '@' << ArgWords;
}
void Mangler::getNameWithPrefix(raw_ostream &OS, const GlobalValue *GV,
bool CannotUsePrivateLabel) const {
ManglerPrefixTy PrefixTy = Mangler::Default;
if (GV->hasPrivateLinkage()) {
if (CannotUsePrivateLabel)
PrefixTy = Mangler::LinkerPrivate;
else
PrefixTy = Mangler::Private;
}
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 = NextAnonGlobalID++;
// Must mangle the global into a unique ID.
getNameWithPrefix(OS, "__unnamed_" + Twine(ID), PrefixTy);
return;
}
StringRef Name = GV->getName();
bool UseAt = false;
const Function *MSFunc = nullptr;
CallingConv::ID CC;
if (Name[0] != '\1' && DL->hasMicrosoftFastStdCallMangling()) {
if ((MSFunc = dyn_cast<Function>(GV))) {
CC = MSFunc->getCallingConv();
// fastcall functions need to start with @ instead of _.
if (CC == CallingConv::X86_FastCall)
UseAt = true;
}
}
getNameWithPrefixx(OS, Name, PrefixTy, *DL, UseAt);
if (!MSFunc)
return;
// If we are supposed to add a microsoft-style suffix for stdcall/fastcall,
// add it.
// fastcall and stdcall functions usually need @42 at the end to specify
// the argument info.
FunctionType *FT = MSFunc->getFunctionType();
if ((CC == CallingConv::X86_FastCall || CC == CallingConv::X86_StdCall) &&
// "Pure" variadic functions do not receive @0 suffix.
(!FT->isVarArg() || FT->getNumParams() == 0 ||
(FT->getNumParams() == 1 && MSFunc->hasStructRetAttr())))
AddFastCallStdCallSuffix(OS, MSFunc, *DL);
}
void Mangler::getNameWithPrefix(SmallVectorImpl<char> &OutName,
const GlobalValue *GV,
bool CannotUsePrivateLabel) const {
raw_svector_ostream OS(OutName);
getNameWithPrefix(OS, GV, CannotUsePrivateLabel);
}