llvm-project/lld/lib/ReaderWriter/ELF/X86/X86TargetHandler.cpp

73 lines
2.4 KiB
C++

//===- lib/ReaderWriter/ELF/X86/X86TargetHandler.cpp ----------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "X86TargetHandler.h"
#include "X86TargetInfo.h"
using namespace lld;
using namespace elf;
using namespace llvm::ELF;
namespace {
/// \brief R_386_32 - word32: S + A
int reloc32(uint8_t *location, uint64_t P, uint64_t S, uint64_t A) {
int32_t result = (uint32_t)(S + A);
*reinterpret_cast<llvm::support::ulittle32_t *>(location) = result |
(uint32_t)*reinterpret_cast<llvm::support::ulittle32_t *>(location);
return 0;
}
/// \brief R_386_PC32 - word32: S + A - P
int relocPC32(uint8_t *location, uint64_t P, uint64_t S, uint64_t A) {
uint32_t result = (uint32_t)((S + A) - P);
*reinterpret_cast<llvm::support::ulittle32_t *>(location) = result +
(uint32_t)*reinterpret_cast<llvm::support::ulittle32_t *>(location);
return 0;
}
} // end anon namespace
ErrorOr<void> 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();
switch (ref.kind()) {
case R_386_32:
reloc32(location, relocVAddress, targetVAddress, ref.addend());
break;
case R_386_PC32:
relocPC32(location, relocVAddress, targetVAddress, ref.addend());
break;
case lld::Reference::kindLayoutAfter:
case lld::Reference::kindLayoutBefore:
case lld::Reference::kindInGroup:
break;
default : {
std::string str;
llvm::raw_string_ostream s(str);
auto name = _targetInfo.stringFromRelocKind(ref.kind());
s << "Unhandled relocation: "
<< (name ? *name : "<unknown>" ) << " (" << ref.kind() << ")";
s.flush();
llvm_unreachable(str.c_str());
}
}
return error_code::success();
}
X86TargetHandler::X86TargetHandler(X86TargetInfo &targetInfo)
: DefaultTargetHandler(targetInfo), _relocationHandler(targetInfo),
_targetLayout(targetInfo) {
}