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//===- 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 "ELFReader.h"
#include <map>
#include <vector>
using llvm::support::endianness;
using namespace llvm::object;
namespace lld {
namespace {
struct DynamicFileCreateELFTraits {
typedef llvm::ErrorOr<std::unique_ptr<lld::SharedLibraryFile>> result_type;
template <class ELFT>
static result_type create(std::unique_ptr<llvm::MemoryBuffer> mb,
bool useUndefines) {
return lld::elf::DynamicFile<ELFT>::create(std::move(mb), useUndefines);
}
};
struct ELFFileCreateELFTraits {
typedef llvm::ErrorOr<std::unique_ptr<lld::File>> result_type;
template <class ELFT>
static result_type create(std::unique_ptr<llvm::MemoryBuffer> mb,
bool atomizeStrings) {
return lld::elf::ELFFile<ELFT>::create(std::move(mb), atomizeStrings);
}
};
class ELFObjectReader : public Reader {
public:
ELFObjectReader(bool atomizeStrings) : _atomizeStrings(atomizeStrings) {}
virtual bool canParse(file_magic magic, StringRef,
const MemoryBuffer &) const override {
return (magic == llvm::sys::fs::file_magic::elf_relocatable);
}
virtual error_code
parseFile(std::unique_ptr<MemoryBuffer> &mb, const class Registry &,
std::vector<std::unique_ptr<File>> &result) const override {
error_code ec;
std::size_t maxAlignment =
1ULL << llvm::countTrailingZeros(uintptr_t(mb->getBufferStart()));
auto f = createELF<ELFFileCreateELFTraits>(
getElfArchType(&*mb), maxAlignment, std::move(mb), _atomizeStrings);
if (error_code ec = f.getError())
return ec;
result.push_back(std::move(*f));
return error_code::success();
}
private:
bool _atomizeStrings;
};
class ELFDSOReader : public Reader {
public:
ELFDSOReader(bool useUndefines) : _useUndefines(useUndefines) {}
virtual bool canParse(file_magic magic, StringRef,
const MemoryBuffer &) const override {
return (magic == llvm::sys::fs::file_magic::elf_shared_object);
}
virtual error_code
parseFile(std::unique_ptr<MemoryBuffer> &mb, const class Registry &,
std::vector<std::unique_ptr<File>> &result) const override {
std::size_t maxAlignment =
1ULL << llvm::countTrailingZeros(uintptr_t(mb->getBufferStart()));
auto f = createELF<DynamicFileCreateELFTraits>(
getElfArchType(&*mb), maxAlignment, std::move(mb), _useUndefines);
if (error_code ec = f.getError())
return ec;
result.push_back(std::move(*f));
return error_code::success();
}
private:
bool _useUndefines;
};
} // anonymous
// This dynamic registration of a handler causes support for all ELF
// architectures to be pulled into the linker. If we want to support making a
// linker that only supports one ELF architecture, we'd need to change this
// to have a different registration method for each architecture.
void Registry::addSupportELFObjects(bool atomizeStrings,
TargetHandlerBase *handler) {
// Tell registry about the ELF object file parser.
add(std::move(handler->getObjReader(atomizeStrings)));
// Tell registry about the relocation name to number mapping for this arch.
handler->registerRelocationNames(*this);
}
void Registry::addSupportELFDynamicSharedObjects(bool useShlibUndefines,
TargetHandlerBase *handler) {
// Tell registry about the ELF dynamic shared library file parser.
add(handler->getDSOReader(useShlibUndefines));
}
} // end namespace lld
|
