llvm-project/llvm/lib/Target/X86/X86ELFWriterInfo.cpp

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//===-- X86ELFWriterInfo.cpp - ELF Writer Info for the X86 backend --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements ELF writer information for the X86 backend.
//
//===----------------------------------------------------------------------===//
#include "X86ELFWriterInfo.h"
#include "X86Relocations.h"
#include "llvm/Function.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetMachine.h"
using namespace llvm;
//===----------------------------------------------------------------------===//
// Implementation of the X86ELFWriterInfo class
//===----------------------------------------------------------------------===//
X86ELFWriterInfo::X86ELFWriterInfo(bool is64Bit_, bool isLittleEndian_)
: TargetELFWriterInfo(is64Bit_, isLittleEndian_) {
EMachine = is64Bit ? EM_X86_64 : EM_386;
}
X86ELFWriterInfo::~X86ELFWriterInfo() {}
unsigned X86ELFWriterInfo::getRelocationType(unsigned MachineRelTy) const {
if (is64Bit) {
switch(MachineRelTy) {
case X86::reloc_pcrel_word:
return ELF::R_X86_64_PC32;
case X86::reloc_absolute_word:
return ELF::R_X86_64_32;
case X86::reloc_absolute_word_sext:
return ELF::R_X86_64_32S;
case X86::reloc_absolute_dword:
return ELF::R_X86_64_64;
case X86::reloc_picrel_word:
default:
llvm_unreachable("unknown x86_64 machine relocation type");
}
} else {
switch(MachineRelTy) {
case X86::reloc_pcrel_word:
return ELF::R_386_PC32;
case X86::reloc_absolute_word:
return ELF::R_386_32;
case X86::reloc_absolute_word_sext:
case X86::reloc_absolute_dword:
case X86::reloc_picrel_word:
default:
llvm_unreachable("unknown x86 machine relocation type");
}
}
return 0;
}
long int X86ELFWriterInfo::getDefaultAddendForRelTy(unsigned RelTy,
long int Modifier) const {
if (is64Bit) {
switch(RelTy) {
case ELF::R_X86_64_PC32: return Modifier - 4;
case ELF::R_X86_64_32:
case ELF::R_X86_64_32S:
case ELF::R_X86_64_64:
return Modifier;
default:
llvm_unreachable("unknown x86_64 relocation type");
}
} else {
switch(RelTy) {
case ELF::R_386_PC32: return Modifier - 4;
case ELF::R_386_32: return Modifier;
default:
llvm_unreachable("unknown x86 relocation type");
}
}
return 0;
}
unsigned X86ELFWriterInfo::getRelocationTySize(unsigned RelTy) const {
if (is64Bit) {
switch(RelTy) {
case ELF::R_X86_64_PC32:
case ELF::R_X86_64_32:
case ELF::R_X86_64_32S:
return 32;
case ELF::R_X86_64_64:
return 64;
default:
llvm_unreachable("unknown x86_64 relocation type");
}
} else {
switch(RelTy) {
case ELF::R_386_PC32:
case ELF::R_386_32:
return 32;
default:
llvm_unreachable("unknown x86 relocation type");
}
}
return 0;
}
bool X86ELFWriterInfo::isPCRelativeRel(unsigned RelTy) const {
if (is64Bit) {
switch(RelTy) {
case ELF::R_X86_64_PC32:
return true;
case ELF::R_X86_64_32:
case ELF::R_X86_64_32S:
case ELF::R_X86_64_64:
return false;
default:
llvm_unreachable("unknown x86_64 relocation type");
}
} else {
switch(RelTy) {
case ELF::R_386_PC32:
return true;
case ELF::R_386_32:
return false;
default:
llvm_unreachable("unknown x86 relocation type");
}
}
return 0;
}
unsigned X86ELFWriterInfo::getAbsoluteLabelMachineRelTy() const {
return is64Bit ?
X86::reloc_absolute_dword : X86::reloc_absolute_word;
}
long int X86ELFWriterInfo::computeRelocation(unsigned SymOffset,
unsigned RelOffset,
unsigned RelTy) const {
if (RelTy == ELF::R_X86_64_PC32 || RelTy == ELF::R_386_PC32)
return SymOffset - (RelOffset + 4);
else
assert(0 && "computeRelocation unknown for this relocation type");
return 0;
}