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//===-- X86ELFObjectWriter.cpp - X86 ELF Writer ---------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "MCTargetDesc/X86FixupKinds.h"
#include "MCTargetDesc/X86MCTargetDesc.h"
#include "llvm/MC/MCELFObjectWriter.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCValue.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/ErrorHandling.h"
using namespace llvm;
namespace {
class X86ELFObjectWriter : public MCELFObjectTargetWriter {
public:
X86ELFObjectWriter(bool IsELF64, uint8_t OSABI, uint16_t EMachine);
virtual ~X86ELFObjectWriter();
protected:
virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
bool IsPCRel, bool IsRelocWithSymbol,
int64_t Addend) const;
};
}
X86ELFObjectWriter::X86ELFObjectWriter(bool IsELF64, uint8_t OSABI,
uint16_t EMachine)
: MCELFObjectTargetWriter(IsELF64, OSABI, EMachine,
// Only i386 uses Rel instead of RelA.
/*HasRelocationAddend*/ EMachine != ELF::EM_386) {}
X86ELFObjectWriter::~X86ELFObjectWriter()
{}
unsigned X86ELFObjectWriter::GetRelocType(const MCValue &Target,
const MCFixup &Fixup,
bool IsPCRel,
bool IsRelocWithSymbol,
int64_t Addend) const {
// determine the type of the relocation
MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
unsigned Type;
if (getEMachine() == ELF::EM_X86_64) {
if (IsPCRel) {
switch ((unsigned)Fixup.getKind()) {
default: llvm_unreachable("invalid fixup kind!");
case FK_Data_8: Type = ELF::R_X86_64_PC64; break;
case FK_Data_4: Type = ELF::R_X86_64_PC32; break;
case FK_Data_2: Type = ELF::R_X86_64_PC16; break;
case FK_PCRel_8:
assert(Modifier == MCSymbolRefExpr::VK_None);
Type = ELF::R_X86_64_PC64;
break;
case X86::reloc_signed_4byte:
case X86::reloc_riprel_4byte_movq_load:
case X86::reloc_riprel_4byte:
case FK_PCRel_4:
switch (Modifier) {
default:
llvm_unreachable("Unimplemented");
case MCSymbolRefExpr::VK_None:
Type = ELF::R_X86_64_PC32;
break;
case MCSymbolRefExpr::VK_PLT:
Type = ELF::R_X86_64_PLT32;
break;
case MCSymbolRefExpr::VK_GOTPCREL:
Type = ELF::R_X86_64_GOTPCREL;
break;
case MCSymbolRefExpr::VK_GOTTPOFF:
Type = ELF::R_X86_64_GOTTPOFF;
break;
case MCSymbolRefExpr::VK_TLSGD:
Type = ELF::R_X86_64_TLSGD;
break;
case MCSymbolRefExpr::VK_TLSLD:
Type = ELF::R_X86_64_TLSLD;
break;
}
break;
case FK_PCRel_2:
assert(Modifier == MCSymbolRefExpr::VK_None);
Type = ELF::R_X86_64_PC16;
break;
case FK_PCRel_1:
assert(Modifier == MCSymbolRefExpr::VK_None);
Type = ELF::R_X86_64_PC8;
break;
}
} else {
switch ((unsigned)Fixup.getKind()) {
default: llvm_unreachable("invalid fixup kind!");
case FK_Data_8:
switch (Modifier) {
default:
llvm_unreachable("Unimplemented");
case MCSymbolRefExpr::VK_None:
Type = ELF::R_X86_64_64;
break;
case MCSymbolRefExpr::VK_DTPOFF:
Type = ELF::R_X86_64_DTPOFF64;
break;
}
break;
case X86::reloc_signed_4byte:
switch (Modifier) {
default:
llvm_unreachable("Unimplemented");
case MCSymbolRefExpr::VK_None:
Type = ELF::R_X86_64_32S;
break;
case MCSymbolRefExpr::VK_GOT:
Type = ELF::R_X86_64_GOT32;
break;
case MCSymbolRefExpr::VK_GOTPCREL:
Type = ELF::R_X86_64_GOTPCREL;
break;
case MCSymbolRefExpr::VK_TPOFF:
Type = ELF::R_X86_64_TPOFF32;
break;
case MCSymbolRefExpr::VK_DTPOFF:
Type = ELF::R_X86_64_DTPOFF32;
break;
}
break;
case FK_Data_4:
Type = ELF::R_X86_64_32;
break;
case FK_Data_2: Type = ELF::R_X86_64_16; break;
case FK_PCRel_1:
case FK_Data_1: Type = ELF::R_X86_64_8; break;
}
}
} else if (getEMachine() == ELF::EM_386) {
if (IsPCRel) {
switch ((unsigned)Fixup.getKind()) {
default: llvm_unreachable("invalid fixup kind!");
case X86::reloc_global_offset_table:
Type = ELF::R_386_GOTPC;
break;
case X86::reloc_signed_4byte:
case FK_PCRel_4:
case FK_Data_4:
switch (Modifier) {
default:
llvm_unreachable("Unimplemented");
case MCSymbolRefExpr::VK_None:
Type = ELF::R_386_PC32;
break;
case MCSymbolRefExpr::VK_PLT:
Type = ELF::R_386_PLT32;
break;
}
break;
}
} else {
switch ((unsigned)Fixup.getKind()) {
default: llvm_unreachable("invalid fixup kind!");
case X86::reloc_global_offset_table:
Type = ELF::R_386_GOTPC;
break;
// FIXME: Should we avoid selecting reloc_signed_4byte in 32 bit mode
// instead?
case X86::reloc_signed_4byte:
case FK_PCRel_4:
case FK_Data_4:
switch (Modifier) {
default:
llvm_unreachable("Unimplemented");
case MCSymbolRefExpr::VK_None:
Type = ELF::R_386_32;
break;
case MCSymbolRefExpr::VK_GOT:
Type = ELF::R_386_GOT32;
break;
case MCSymbolRefExpr::VK_GOTOFF:
Type = ELF::R_386_GOTOFF;
break;
case MCSymbolRefExpr::VK_TLSGD:
Type = ELF::R_386_TLS_GD;
break;
case MCSymbolRefExpr::VK_TPOFF:
Type = ELF::R_386_TLS_LE_32;
break;
case MCSymbolRefExpr::VK_INDNTPOFF:
Type = ELF::R_386_TLS_IE;
break;
case MCSymbolRefExpr::VK_NTPOFF:
Type = ELF::R_386_TLS_LE;
break;
case MCSymbolRefExpr::VK_GOTNTPOFF:
Type = ELF::R_386_TLS_GOTIE;
break;
case MCSymbolRefExpr::VK_TLSLDM:
Type = ELF::R_386_TLS_LDM;
break;
case MCSymbolRefExpr::VK_DTPOFF:
Type = ELF::R_386_TLS_LDO_32;
break;
case MCSymbolRefExpr::VK_GOTTPOFF:
Type = ELF::R_386_TLS_IE_32;
break;
}
break;
case FK_Data_2: Type = ELF::R_386_16; break;
case FK_PCRel_1:
case FK_Data_1: Type = ELF::R_386_8; break;
}
}
} else
llvm_unreachable("Unsupported ELF machine type.");
return Type;
}
MCObjectWriter *llvm::createX86ELFObjectWriter(raw_ostream &OS,
bool IsELF64,
uint8_t OSABI,
uint16_t EMachine) {
MCELFObjectTargetWriter *MOTW =
new X86ELFObjectWriter(IsELF64, OSABI, EMachine);
return createELFObjectWriter(MOTW, OS, /*IsLittleEndian=*/true);
}
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