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//===-- X86TargetObjectFile.cpp - X86 Object Info -------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "X86TargetObjectFile.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/IR/Mangler.h"
#include "llvm/IR/Operator.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCSectionCOFF.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCValue.h"
#include "llvm/Support/COFF.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Target/TargetLowering.h"
using namespace llvm;
using namespace dwarf;
const MCExpr *X86_64MachoTargetObjectFile::getTTypeGlobalReference(
const GlobalValue *GV, unsigned Encoding, Mangler &Mang,
const TargetMachine &TM, MachineModuleInfo *MMI,
MCStreamer &Streamer) const {
// On Darwin/X86-64, we can reference dwarf symbols with foo@GOTPCREL+4, which
// is an indirect pc-relative reference.
if ((Encoding & DW_EH_PE_indirect) && (Encoding & DW_EH_PE_pcrel)) {
const MCSymbol *Sym = TM.getSymbol(GV, Mang);
const MCExpr *Res =
MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_GOTPCREL, getContext());
const MCExpr *Four = MCConstantExpr::create(4, getContext());
return MCBinaryExpr::createAdd(Res, Four, getContext());
}
return TargetLoweringObjectFileMachO::getTTypeGlobalReference(
GV, Encoding, Mang, TM, MMI, Streamer);
}
MCSymbol *X86_64MachoTargetObjectFile::getCFIPersonalitySymbol(
const GlobalValue *GV, Mangler &Mang, const TargetMachine &TM,
MachineModuleInfo *MMI) const {
return TM.getSymbol(GV, Mang);
}
const MCExpr *X86_64MachoTargetObjectFile::getIndirectSymViaGOTPCRel(
const MCSymbol *Sym, const MCValue &MV, int64_t Offset,
MachineModuleInfo *MMI, MCStreamer &Streamer) const {
// On Darwin/X86-64, we need to use foo@GOTPCREL+4 to access the got entry
// from a data section. In case there's an additional offset, then use
// foo@GOTPCREL+4+<offset>.
unsigned FinalOff = Offset+MV.getConstant()+4;
const MCExpr *Res =
MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_GOTPCREL, getContext());
const MCExpr *Off = MCConstantExpr::create(FinalOff, getContext());
return MCBinaryExpr::createAdd(Res, Off, getContext());
}
const MCExpr *X86ELFTargetObjectFile::getDebugThreadLocalSymbol(
const MCSymbol *Sym) const {
return MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_DTPOFF, getContext());
}
void
X86LinuxNaClTargetObjectFile::Initialize(MCContext &Ctx,
const TargetMachine &TM) {
TargetLoweringObjectFileELF::Initialize(Ctx, TM);
InitializeELF(TM.Options.UseInitArray);
}
const MCExpr *X86WindowsTargetObjectFile::lowerRelativeReference(
const GlobalValue *LHS, const GlobalValue *RHS, Mangler &Mang,
const TargetMachine &TM) const {
// Our symbols should exist in address space zero, cowardly no-op if
// otherwise.
if (LHS->getType()->getPointerAddressSpace() != 0 ||
RHS->getType()->getPointerAddressSpace() != 0)
return nullptr;
// Both ptrtoint instructions must wrap global objects:
// - Only global variables are eligible for image relative relocations.
// - The subtrahend refers to the special symbol __ImageBase, a GlobalVariable.
// We expect __ImageBase to be a global variable without a section, externally
// defined.
//
// It should look something like this: @__ImageBase = external constant i8
if (!isa<GlobalObject>(LHS) || !isa<GlobalVariable>(RHS) ||
LHS->isThreadLocal() || RHS->isThreadLocal() ||
RHS->getName() != "__ImageBase" || !RHS->hasExternalLinkage() ||
cast<GlobalVariable>(RHS)->hasInitializer() || RHS->hasSection())
return nullptr;
return MCSymbolRefExpr::create(
TM.getSymbol(LHS, Mang), MCSymbolRefExpr::VK_COFF_IMGREL32, getContext());
}
static std::string APIntToHexString(const APInt &AI) {
unsigned Width = (AI.getBitWidth() / 8) * 2;
std::string HexString = utohexstr(AI.getLimitedValue(), /*LowerCase=*/true);
unsigned Size = HexString.size();
assert(Width >= Size && "hex string is too large!");
HexString.insert(HexString.begin(), Width - Size, '0');
return HexString;
}
static std::string scalarConstantToHexString(const Constant *C) {
Type *Ty = C->getType();
if (isa<UndefValue>(C)) {
return APIntToHexString(APInt::getNullValue(Ty->getPrimitiveSizeInBits()));
} else if (const auto *CFP = dyn_cast<ConstantFP>(C)) {
return APIntToHexString(CFP->getValueAPF().bitcastToAPInt());
} else if (const auto *CI = dyn_cast<ConstantInt>(C)) {
return APIntToHexString(CI->getValue());
} else {
unsigned NumElements;
if (isa<VectorType>(Ty))
NumElements = Ty->getVectorNumElements();
else
NumElements = Ty->getArrayNumElements();
std::string HexString;
for (int I = NumElements - 1, E = -1; I != E; --I)
HexString += scalarConstantToHexString(C->getAggregateElement(I));
return HexString;
}
}
MCSection *X86WindowsTargetObjectFile::getSectionForConstant(
const DataLayout &DL, SectionKind Kind, const Constant *C,
unsigned &Align) const {
if (Kind.isMergeableConst() && C) {
const unsigned Characteristics = COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ |
COFF::IMAGE_SCN_LNK_COMDAT;
std::string COMDATSymName;
if (Kind.isMergeableConst4()) {
if (Align <= 4) {
COMDATSymName = "__real@" + scalarConstantToHexString(C);
Align = 4;
}
} else if (Kind.isMergeableConst8()) {
if (Align <= 8) {
COMDATSymName = "__real@" + scalarConstantToHexString(C);
Align = 8;
}
} else if (Kind.isMergeableConst16()) {
if (Align <= 16) {
COMDATSymName = "__xmm@" + scalarConstantToHexString(C);
Align = 16;
}
} else if (Kind.isMergeableConst32()) {
if (Align <= 32) {
COMDATSymName = "__ymm@" + scalarConstantToHexString(C);
Align = 32;
}
}
if (!COMDATSymName.empty())
return getContext().getCOFFSection(".rdata", Characteristics, Kind,
COMDATSymName,
COFF::IMAGE_COMDAT_SELECT_ANY);
}
return TargetLoweringObjectFile::getSectionForConstant(DL, Kind, C, Align);
}
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