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"
17 #include "llvm/Target/TargetLowering.h"
20 using namespace dwarf;
22 const MCExpr *X86_64MachoTargetObjectFile::getTTypeGlobalReference(
23 const GlobalValue *GV, unsigned Encoding, Mangler &Mang,
24 const TargetMachine &TM, MachineModuleInfo *MMI,
25 MCStreamer &Streamer) const {
27 // On Darwin/X86-64, we can reference dwarf symbols with foo@GOTPCREL+4, which
28 // is an indirect pc-relative reference.
29 if (Encoding & (DW_EH_PE_indirect | DW_EH_PE_pcrel)) {
30 const MCSymbol *Sym = TM.getSymbol(GV, Mang);
32 MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_GOTPCREL, getContext());
33 const MCExpr *Four = MCConstantExpr::Create(4, getContext());
34 return MCBinaryExpr::CreateAdd(Res, Four, getContext());
37 return TargetLoweringObjectFileMachO::getTTypeGlobalReference(
38 GV, Encoding, Mang, TM, MMI, Streamer);
41 MCSymbol *X86_64MachoTargetObjectFile::getCFIPersonalitySymbol(
42 const GlobalValue *GV, Mangler &Mang, const TargetMachine &TM,
43 MachineModuleInfo *MMI) const {
44 return TM.getSymbol(GV, Mang);
48 X86LinuxTargetObjectFile::Initialize(MCContext &Ctx, const TargetMachine &TM) {
49 TargetLoweringObjectFileELF::Initialize(Ctx, TM);
50 InitializeELF(TM.Options.UseInitArray);
54 X86LinuxTargetObjectFile::getDebugThreadLocalSymbol(
55 const MCSymbol *Sym) const {
56 return MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_DTPOFF, getContext());
59 const MCExpr *X86WindowsTargetObjectFile::getExecutableRelativeSymbol(
60 const ConstantExpr *CE, Mangler &Mang, const TargetMachine &TM) const {
61 // We are looking for the difference of two symbols, need a subtraction
63 const SubOperator *Sub = dyn_cast<SubOperator>(CE);
67 // Symbols must first be numbers before we can subtract them, we need to see a
68 // ptrtoint on both subtraction operands.
69 const PtrToIntOperator *SubLHS =
70 dyn_cast<PtrToIntOperator>(Sub->getOperand(0));
71 const PtrToIntOperator *SubRHS =
72 dyn_cast<PtrToIntOperator>(Sub->getOperand(1));
73 if (!SubLHS || !SubRHS)
76 // Our symbols should exist in address space zero, cowardly no-op if
78 if (SubLHS->getPointerAddressSpace() != 0 ||
79 SubRHS->getPointerAddressSpace() != 0)
82 // Both ptrtoint instructions must wrap global variables:
83 // - Only global variables are eligible for image relative relocations.
84 // - The subtrahend refers to the special symbol __ImageBase, a global.
85 const GlobalVariable *GVLHS =
86 dyn_cast<GlobalVariable>(SubLHS->getPointerOperand());
87 const GlobalVariable *GVRHS =
88 dyn_cast<GlobalVariable>(SubRHS->getPointerOperand());
92 // We expect __ImageBase to be a global variable without a section, externally
95 // It should look something like this: @__ImageBase = external constant i8
96 if (GVRHS->isThreadLocal() || GVRHS->getName() != "__ImageBase" ||
97 !GVRHS->hasExternalLinkage() || GVRHS->hasInitializer() ||
101 // An image-relative, thread-local, symbol makes no sense.
102 if (GVLHS->isThreadLocal())
105 return MCSymbolRefExpr::Create(TM.getSymbol(GVLHS, Mang),
106 MCSymbolRefExpr::VK_COFF_IMGREL32,