daeafb4c2a
r201608 made llvm corretly handle private globals with MachO. r201622 fixed a bug in it and r201624 and r201625 were changes for using private linkage, assuming that llvm would do the right thing. They all got reverted because r201608 introduced a crash in LTO. This patch includes a fix for that. The issue was that TargetLoweringObjectFile now has to be initialized before we can mangle names of private globals. This is trivially true during the normal codegen pipeline (the asm printer does it), but LTO has to do it manually. llvm-svn: 201700
109 lines
3.9 KiB
C++
109 lines
3.9 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/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/MCSectionELF.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 | DW_EH_PE_pcrel)) {
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const MCSymbol *Sym = TM.getTargetLowering()->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.getTargetLowering()->getSymbol(GV, Mang);
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}
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void
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X86LinuxTargetObjectFile::Initialize(MCContext &Ctx, 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 *
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X86LinuxTargetObjectFile::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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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 0;
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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 0;
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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 0;
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// Both ptrtoint instructions must wrap global variables:
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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 global.
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const GlobalVariable *GVLHS =
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dyn_cast<GlobalVariable>(SubLHS->getPointerOperand());
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const GlobalVariable *GVRHS =
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dyn_cast<GlobalVariable>(SubRHS->getPointerOperand());
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if (!GVLHS || !GVRHS)
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return 0;
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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 0;
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// An image-relative, thread-local, symbol makes no sense.
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if (GVLHS->isThreadLocal())
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return 0;
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return MCSymbolRefExpr::Create(TM.getTargetLowering()->getSymbol(GVLHS, Mang),
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MCSymbolRefExpr::VK_COFF_IMGREL32,
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getContext());
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}
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