mirror of
https://github.com/c64scene-ar/llvm-6502.git
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Summary: The generic ELF TargetObjectFile defaults to .ctors, but Linux's defaults to .init_array by calling InitializeELF with the value of UseInitArray from TargetMachine. Make NaCl's behavior match. Reviewers: jvoung Differential Revision: http://reviews.llvm.org/D8240 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231934 91177308-0d34-0410-b5e6-96231b3b80d8
184 lines
6.8 KiB
C++
184 lines
6.8 KiB
C++
//===-- X86TargetObjectFile.cpp - X86 Object Info -------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "X86TargetObjectFile.h"
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#include "llvm/ADT/StringExtras.h"
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#include "llvm/IR/Mangler.h"
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#include "llvm/IR/Operator.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCSectionCOFF.h"
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#include "llvm/MC/MCSectionELF.h"
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#include "llvm/MC/MCValue.h"
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#include "llvm/Support/Dwarf.h"
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#include "llvm/Target/TargetLowering.h"
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using namespace llvm;
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using namespace dwarf;
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const MCExpr *X86_64MachoTargetObjectFile::getTTypeGlobalReference(
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const GlobalValue *GV, unsigned Encoding, Mangler &Mang,
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const TargetMachine &TM, MachineModuleInfo *MMI,
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MCStreamer &Streamer) const {
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// On Darwin/X86-64, we can reference dwarf symbols with foo@GOTPCREL+4, which
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// is an indirect pc-relative reference.
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if ((Encoding & DW_EH_PE_indirect) && (Encoding & DW_EH_PE_pcrel)) {
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const MCSymbol *Sym = TM.getSymbol(GV, Mang);
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const MCExpr *Res =
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MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_GOTPCREL, getContext());
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const MCExpr *Four = MCConstantExpr::Create(4, getContext());
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return MCBinaryExpr::CreateAdd(Res, Four, getContext());
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}
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return TargetLoweringObjectFileMachO::getTTypeGlobalReference(
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GV, Encoding, Mang, TM, MMI, Streamer);
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}
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MCSymbol *X86_64MachoTargetObjectFile::getCFIPersonalitySymbol(
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const GlobalValue *GV, Mangler &Mang, const TargetMachine &TM,
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MachineModuleInfo *MMI) const {
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return TM.getSymbol(GV, Mang);
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}
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const MCExpr *X86_64MachoTargetObjectFile::getIndirectSymViaGOTPCRel(
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const MCSymbol *Sym, const MCValue &MV, int64_t Offset,
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MachineModuleInfo *MMI, MCStreamer &Streamer) const {
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// On Darwin/X86-64, we need to use foo@GOTPCREL+4 to access the got entry
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// from a data section. In case there's an additional offset, then use
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// foo@GOTPCREL+4+<offset>.
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unsigned FinalOff = Offset+MV.getConstant()+4;
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const MCExpr *Res =
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MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_GOTPCREL, getContext());
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const MCExpr *Off = MCConstantExpr::Create(FinalOff, getContext());
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return MCBinaryExpr::CreateAdd(Res, Off, getContext());
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}
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const MCExpr *X86ELFTargetObjectFile::getDebugThreadLocalSymbol(
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const MCSymbol *Sym) const {
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return MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_DTPOFF, getContext());
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}
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void
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X86LinuxNaClTargetObjectFile::Initialize(MCContext &Ctx,
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const TargetMachine &TM) {
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TargetLoweringObjectFileELF::Initialize(Ctx, TM);
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InitializeELF(TM.Options.UseInitArray);
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}
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const MCExpr *X86WindowsTargetObjectFile::getExecutableRelativeSymbol(
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const ConstantExpr *CE, Mangler &Mang, const TargetMachine &TM) const {
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// We are looking for the difference of two symbols, need a subtraction
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// operation.
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const SubOperator *Sub = dyn_cast<SubOperator>(CE);
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if (!Sub)
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return nullptr;
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// Symbols must first be numbers before we can subtract them, we need to see a
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// ptrtoint on both subtraction operands.
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const PtrToIntOperator *SubLHS =
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dyn_cast<PtrToIntOperator>(Sub->getOperand(0));
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const PtrToIntOperator *SubRHS =
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dyn_cast<PtrToIntOperator>(Sub->getOperand(1));
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if (!SubLHS || !SubRHS)
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return nullptr;
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// Our symbols should exist in address space zero, cowardly no-op if
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// otherwise.
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if (SubLHS->getPointerAddressSpace() != 0 ||
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SubRHS->getPointerAddressSpace() != 0)
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return nullptr;
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// Both ptrtoint instructions must wrap global objects:
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// - Only global variables are eligible for image relative relocations.
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// - The subtrahend refers to the special symbol __ImageBase, a GlobalVariable.
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const auto *GOLHS = dyn_cast<GlobalObject>(SubLHS->getPointerOperand());
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const auto *GVRHS = dyn_cast<GlobalVariable>(SubRHS->getPointerOperand());
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if (!GOLHS || !GVRHS)
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return nullptr;
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// We expect __ImageBase to be a global variable without a section, externally
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// defined.
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//
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// It should look something like this: @__ImageBase = external constant i8
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if (GVRHS->isThreadLocal() || GVRHS->getName() != "__ImageBase" ||
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!GVRHS->hasExternalLinkage() || GVRHS->hasInitializer() ||
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GVRHS->hasSection())
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return nullptr;
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// An image-relative, thread-local, symbol makes no sense.
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if (GOLHS->isThreadLocal())
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return nullptr;
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return MCSymbolRefExpr::Create(TM.getSymbol(GOLHS, Mang),
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MCSymbolRefExpr::VK_COFF_IMGREL32,
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getContext());
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}
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static std::string APIntToHexString(const APInt &AI) {
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unsigned Width = (AI.getBitWidth() / 8) * 2;
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std::string HexString = utohexstr(AI.getLimitedValue(), /*LowerCase=*/true);
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unsigned Size = HexString.size();
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assert(Width >= Size && "hex string is too large!");
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HexString.insert(HexString.begin(), Width - Size, '0');
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return HexString;
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}
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static std::string scalarConstantToHexString(const Constant *C) {
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Type *Ty = C->getType();
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APInt AI;
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if (isa<UndefValue>(C)) {
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AI = APInt(Ty->getPrimitiveSizeInBits(), /*val=*/0);
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} else if (Ty->isFloatTy() || Ty->isDoubleTy()) {
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const auto *CFP = cast<ConstantFP>(C);
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AI = CFP->getValueAPF().bitcastToAPInt();
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} else if (Ty->isIntegerTy()) {
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const auto *CI = cast<ConstantInt>(C);
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AI = CI->getValue();
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} else {
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llvm_unreachable("unexpected constant pool element type!");
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}
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return APIntToHexString(AI);
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}
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const MCSection *
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X86WindowsTargetObjectFile::getSectionForConstant(SectionKind Kind,
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const Constant *C) const {
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if (Kind.isReadOnly()) {
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if (C) {
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Type *Ty = C->getType();
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SmallString<32> COMDATSymName;
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if (Ty->isFloatTy() || Ty->isDoubleTy()) {
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COMDATSymName = "__real@";
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COMDATSymName += scalarConstantToHexString(C);
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} else if (const auto *VTy = dyn_cast<VectorType>(Ty)) {
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uint64_t NumBits = VTy->getBitWidth();
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if (NumBits == 128 || NumBits == 256) {
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COMDATSymName = NumBits == 128 ? "__xmm@" : "__ymm@";
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for (int I = VTy->getNumElements() - 1, E = -1; I != E; --I)
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COMDATSymName +=
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scalarConstantToHexString(C->getAggregateElement(I));
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}
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}
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if (!COMDATSymName.empty()) {
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unsigned Characteristics = COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
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COFF::IMAGE_SCN_MEM_READ |
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COFF::IMAGE_SCN_LNK_COMDAT;
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return getContext().getCOFFSection(".rdata", Characteristics, Kind,
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COMDATSymName,
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COFF::IMAGE_COMDAT_SELECT_ANY);
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}
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}
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}
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return TargetLoweringObjectFile::getSectionForConstant(Kind, C);
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}
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