llvm-project/lld/lib/ReaderWriter/ELF/Reader.cpp

141 lines
4.3 KiB
C++

//===- lib/ReaderWriter/ELF/Reader.cpp ------------------------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief Defines the ELF Reader and all helper sub classes to consume an ELF
/// file and produces atoms out of it.
///
//===----------------------------------------------------------------------===//
#include "lld/ReaderWriter/Reader.h"
#include "Atoms.h"
#include "CreateELF.h"
#include "DynamicFile.h"
#include "File.h"
#include "lld/Core/Reference.h"
#include "lld/ReaderWriter/ELFTargetInfo.h"
#include "lld/ReaderWriter/ReaderArchive.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Object/ELF.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Memory.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/system_error.h"
#include <map>
#include <vector>
using llvm::support::endianness;
using namespace llvm::object;
namespace {
struct DynamicFileCreateELFTraits {
typedef llvm::ErrorOr<std::unique_ptr<lld::SharedLibraryFile>> result_type;
template <class ELFT>
static result_type create(const lld::ELFTargetInfo &ti,
std::unique_ptr<llvm::MemoryBuffer> mb) {
return lld::elf::DynamicFile<ELFT>::create(ti, std::move(mb));
}
};
struct ELFFileCreateELFTraits {
typedef std::unique_ptr<lld::File> result_type;
template <class ELFT>
static result_type create(const lld::ELFTargetInfo &ti,
std::unique_ptr<llvm::MemoryBuffer> mb,
lld::error_code &ec) {
return std::unique_ptr<lld::File>(
new lld::elf::ELFFile<ELFT>(ti, std::move(mb), ec));
}
};
}
namespace lld {
namespace elf {
/// \brief A reader object that will instantiate correct File by examining the
/// memory buffer for ELF class and bit width
class ELFReader : public Reader {
public:
ELFReader(const ELFTargetInfo &ti)
: lld::Reader(ti), _elfTargetInfo(ti), _readerArchive(ti, *this) {
}
error_code parseFile(std::unique_ptr<MemoryBuffer> &mb,
std::vector<std::unique_ptr<File> > &result) const {
using llvm::object::ELFType;
llvm::sys::fs::file_magic FileType =
llvm::sys::fs::identify_magic(mb->getBuffer());
std::size_t MaxAlignment =
1ULL << llvm::countTrailingZeros(uintptr_t(mb->getBufferStart()));
llvm::error_code ec;
switch (FileType) {
case llvm::sys::fs::file_magic::elf_relocatable: {
std::unique_ptr<File> f(createELF<ELFFileCreateELFTraits>(
getElfArchType(&*mb), MaxAlignment, _elfTargetInfo, std::move(mb),
ec));
if (ec)
return ec;
result.push_back(std::move(f));
break;
}
case llvm::sys::fs::file_magic::elf_shared_object: {
// If the link doesnot allow dynamic libraries to be present during the
// link, lets not parse the file and just return
if (!_elfTargetInfo.allowLinkWithDynamicLibraries())
return llvm::make_error_code(llvm::errc::executable_format_error);
auto f = createELF<DynamicFileCreateELFTraits>(
getElfArchType(&*mb), MaxAlignment, _elfTargetInfo, std::move(mb));
if (!f)
return f;
result.push_back(std::move(*f));
break;
}
case llvm::sys::fs::file_magic::archive:
ec = _readerArchive.parseFile(mb, result);
break;
default:
return llvm::make_error_code(llvm::errc::executable_format_error);
break;
}
if (ec)
return ec;
return error_code::success();
}
private:
const ELFTargetInfo &_elfTargetInfo;
ReaderArchive _readerArchive;
};
} // end namespace elf
std::unique_ptr<Reader> createReaderELF(const ELFTargetInfo &targetinfo) {
return std::unique_ptr<Reader>(new elf::ELFReader(targetinfo));
}
} // end namespace lld