1 //===-- X86TargetObjectFile.cpp - X86 Object Info -------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "X86TargetObjectFile.h"
11 #include "llvm/IR/Mangler.h"
12 #include "llvm/IR/Operator.h"
13 #include "llvm/MC/MCContext.h"
14 #include "llvm/MC/MCExpr.h"
15 #include "llvm/MC/MCSectionELF.h"
16 #include "llvm/Support/Dwarf.h"
19 using namespace dwarf;
21 const MCExpr *X86_64MachoTargetObjectFile::getTTypeGlobalReference(
22 const GlobalValue *GV, unsigned Encoding, Mangler &Mang,
23 MachineModuleInfo *MMI, MCStreamer &Streamer) const {
25 // On Darwin/X86-64, we can reference dwarf symbols with foo@GOTPCREL+4, which
26 // is an indirect pc-relative reference.
27 if (Encoding & (DW_EH_PE_indirect | DW_EH_PE_pcrel)) {
28 const MCSymbol *Sym = getSymbol(GV, Mang);
30 MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_GOTPCREL, getContext());
31 const MCExpr *Four = MCConstantExpr::Create(4, getContext());
32 return MCBinaryExpr::CreateAdd(Res, Four, getContext());
35 return TargetLoweringObjectFileMachO::getTTypeGlobalReference(
36 GV, Encoding, Mang, MMI, Streamer);
39 MCSymbol *X86_64MachoTargetObjectFile::
40 getCFIPersonalitySymbol(const GlobalValue *GV, Mangler &Mang,
41 MachineModuleInfo *MMI) const {
42 return getSymbol(GV, Mang);
46 X86LinuxTargetObjectFile::Initialize(MCContext &Ctx, const TargetMachine &TM) {
47 TargetLoweringObjectFileELF::Initialize(Ctx, TM);
48 InitializeELF(TM.Options.UseInitArray);
52 X86LinuxTargetObjectFile::getDebugThreadLocalSymbol(
53 const MCSymbol *Sym) const {
54 return MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_DTPOFF, getContext());
58 X86WindowsTargetObjectFile::getExecutableRelativeSymbol(const ConstantExpr *CE,
59 Mangler &Mang) const {
60 // We are looking for the difference of two symbols, need a subtraction
62 const SubOperator *Sub = dyn_cast<SubOperator>(CE);
66 // Symbols must first be numbers before we can subtract them, we need to see a
67 // ptrtoint on both subtraction operands.
68 const PtrToIntOperator *SubLHS =
69 dyn_cast<PtrToIntOperator>(Sub->getOperand(0));
70 const PtrToIntOperator *SubRHS =
71 dyn_cast<PtrToIntOperator>(Sub->getOperand(1));
72 if (!SubLHS || !SubRHS)
75 // Our symbols should exist in address space zero, cowardly no-op if
77 if (SubLHS->getPointerAddressSpace() != 0 ||
78 SubRHS->getPointerAddressSpace() != 0)
81 // Both ptrtoint instructions must wrap global variables:
82 // - Only global variables are eligible for image relative relocations.
83 // - The subtrahend refers to the special symbol __ImageBase, a global.
84 const GlobalVariable *GVLHS =
85 dyn_cast<GlobalVariable>(SubLHS->getPointerOperand());
86 const GlobalVariable *GVRHS =
87 dyn_cast<GlobalVariable>(SubRHS->getPointerOperand());
91 // We expect __ImageBase to be a global variable without a section, externally
94 // It should look something like this: @__ImageBase = external constant i8
95 if (GVRHS->isThreadLocal() || GVRHS->getName() != "__ImageBase" ||
96 !GVRHS->hasExternalLinkage() || GVRHS->hasInitializer() ||
100 // An image-relative, thread-local, symbol makes no sense.
101 if (GVLHS->isThreadLocal())
104 return MCSymbolRefExpr::Create(
105 getSymbol(GVLHS, Mang), MCSymbolRefExpr::VK_COFF_IMGREL32, getContext());