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//===- lib/ReaderWriter/ELF/X86/X86RelocationHandler.cpp ------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "X86LinkingContext.h"
#include "X86TargetHandler.h"
#include "llvm/Support/Endian.h"
using namespace lld;
using namespace lld::elf;
using namespace llvm::support::endian;
namespace {
/// \brief R_386_32 - word32: S + A
static int reloc32(uint8_t *location, uint64_t P, uint64_t S, uint64_t A) {
int32_t result = (uint32_t)(S + A);
write32le(location, result | read32le(location));
return 0;
}
/// \brief R_386_PC32 - word32: S + A - P
static int relocPC32(uint8_t *location, uint64_t P, uint64_t S, uint64_t A) {
uint32_t result = (uint32_t)((S + A) - P);
write32le(location, result + read32le(location));
return 0;
}
}
std::error_code X86TargetRelocationHandler::applyRelocation(
ELFWriter &writer, llvm::FileOutputBuffer &buf, const lld::AtomLayout &atom,
const Reference &ref) const {
uint8_t *atomContent = buf.getBufferStart() + atom._fileOffset;
uint8_t *location = atomContent + ref.offsetInAtom();
uint64_t targetVAddress = writer.addressOfAtom(ref.target());
uint64_t relocVAddress = atom._virtualAddr + ref.offsetInAtom();
if (ref.kindNamespace() != Reference::KindNamespace::ELF)
return std::error_code();
assert(ref.kindArch() == Reference::KindArch::x86);
switch (ref.kindValue()) {
case R_386_32:
reloc32(location, relocVAddress, targetVAddress, ref.addend());
break;
case R_386_PC32:
relocPC32(location, relocVAddress, targetVAddress, ref.addend());
break;
default:
return make_unhandled_reloc_error();
}
return std::error_code();
}
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