diff options
Diffstat (limited to 'contrib/llvm/lib/Target/X86/X86TargetObjectFile.cpp')
| -rw-r--r-- | contrib/llvm/lib/Target/X86/X86TargetObjectFile.cpp | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Target/X86/X86TargetObjectFile.cpp b/contrib/llvm/lib/Target/X86/X86TargetObjectFile.cpp new file mode 100644 index 000000000000..6f900ea351ef --- /dev/null +++ b/contrib/llvm/lib/Target/X86/X86TargetObjectFile.cpp @@ -0,0 +1,175 @@ +//===-- 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/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::getExecutableRelativeSymbol( + const ConstantExpr *CE, Mangler &Mang, const TargetMachine &TM) const { + // We are looking for the difference of two symbols, need a subtraction + // operation. + const SubOperator *Sub = dyn_cast<SubOperator>(CE); + if (!Sub) + return nullptr; + + // Symbols must first be numbers before we can subtract them, we need to see a + // ptrtoint on both subtraction operands. + const PtrToIntOperator *SubLHS = + dyn_cast<PtrToIntOperator>(Sub->getOperand(0)); + const PtrToIntOperator *SubRHS = + dyn_cast<PtrToIntOperator>(Sub->getOperand(1)); + if (!SubLHS || !SubRHS) + return nullptr; + + // Our symbols should exist in address space zero, cowardly no-op if + // otherwise. + if (SubLHS->getPointerAddressSpace() != 0 || + SubRHS->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. + const auto *GOLHS = dyn_cast<GlobalObject>(SubLHS->getPointerOperand()); + const auto *GVRHS = dyn_cast<GlobalVariable>(SubRHS->getPointerOperand()); + if (!GOLHS || !GVRHS) + return nullptr; + + // We expect __ImageBase to be a global variable without a section, externally + // defined. + // + // It should look something like this: @__ImageBase = external constant i8 + if (GVRHS->isThreadLocal() || GVRHS->getName() != "__ImageBase" || + !GVRHS->hasExternalLinkage() || GVRHS->hasInitializer() || + GVRHS->hasSection()) + return nullptr; + + // An image-relative, thread-local, symbol makes no sense. + if (GOLHS->isThreadLocal()) + return nullptr; + + return MCSymbolRefExpr::create(TM.getSymbol(GOLHS, 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(SectionKind Kind, + const Constant *C) 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() || Kind.isMergeableConst8()) + COMDATSymName = "__real@" + scalarConstantToHexString(C); + else if (Kind.isMergeableConst16()) + COMDATSymName = "__xmm@" + scalarConstantToHexString(C); + + if (!COMDATSymName.empty()) + return getContext().getCOFFSection(".rdata", Characteristics, Kind, + COMDATSymName, + COFF::IMAGE_COMDAT_SELECT_ANY); + } + + return TargetLoweringObjectFile::getSectionForConstant(Kind, C); +} |