llvm/lib/Object/ELFObjectFile.cpp
Rafael Espindola 548f2b6e8f Don't own the buffer in object::Binary.
Owning the buffer is somewhat inflexible. Some Binaries have sub Binaries
(like Archive) and we had to create dummy buffers just to handle that. It is
also a bad fit for IRObjectFile where the Module wants to own the buffer too.

Keeping this ownership would make supporting IR inside native objects
particularly painful.

This patch focuses in lib/Object. If something elsewhere used to own an Binary,
now it also owns a MemoryBuffer.

This patch introduces a few new types.

* MemoryBufferRef. This is just a pair of StringRefs for the data and name.
  This is to MemoryBuffer as StringRef is to std::string.
* OwningBinary. A combination of Binary and a MemoryBuffer. This is needed
  for convenience functions that take a filename and return both the
  buffer and the Binary using that buffer.

The C api now uses OwningBinary to avoid any change in semantics. I will start
a new thread to see if we want to change it and how.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216002 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-19 18:44:46 +00:00

82 lines
2.7 KiB
C++

//===- ELFObjectFile.cpp - ELF object file implementation -------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Part of the ELFObjectFile class implementation.
//
//===----------------------------------------------------------------------===//
#include "llvm/Object/ELFObjectFile.h"
#include "llvm/Support/MathExtras.h"
namespace llvm {
using namespace object;
ELFObjectFileBase::ELFObjectFileBase(unsigned int Type, MemoryBufferRef Source)
: ObjectFile(Type, Source) {}
ErrorOr<std::unique_ptr<ObjectFile>>
ObjectFile::createELFObjectFile(MemoryBufferRef Obj) {
std::pair<unsigned char, unsigned char> Ident =
getElfArchType(Obj.getBuffer());
std::size_t MaxAlignment =
1ULL << countTrailingZeros(uintptr_t(Obj.getBufferStart()));
std::error_code EC;
std::unique_ptr<ObjectFile> R;
if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2LSB)
#if !LLVM_IS_UNALIGNED_ACCESS_FAST
if (MaxAlignment >= 4)
R.reset(new ELFObjectFile<ELFType<support::little, 4, false>>(Obj, EC));
else
#endif
if (MaxAlignment >= 2)
R.reset(new ELFObjectFile<ELFType<support::little, 2, false>>(Obj, EC));
else
return object_error::parse_failed;
else if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2MSB)
#if !LLVM_IS_UNALIGNED_ACCESS_FAST
if (MaxAlignment >= 4)
R.reset(new ELFObjectFile<ELFType<support::big, 4, false>>(Obj, EC));
else
#endif
if (MaxAlignment >= 2)
R.reset(new ELFObjectFile<ELFType<support::big, 2, false>>(Obj, EC));
else
return object_error::parse_failed;
else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2MSB)
#if !LLVM_IS_UNALIGNED_ACCESS_FAST
if (MaxAlignment >= 8)
R.reset(new ELFObjectFile<ELFType<support::big, 8, true>>(Obj, EC));
else
#endif
if (MaxAlignment >= 2)
R.reset(new ELFObjectFile<ELFType<support::big, 2, true>>(Obj, EC));
else
return object_error::parse_failed;
else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2LSB) {
#if !LLVM_IS_UNALIGNED_ACCESS_FAST
if (MaxAlignment >= 8)
R.reset(new ELFObjectFile<ELFType<support::little, 8, true>>(Obj, EC));
else
#endif
if (MaxAlignment >= 2)
R.reset(new ELFObjectFile<ELFType<support::little, 2, true>>(Obj, EC));
else
return object_error::parse_failed;
}
else
llvm_unreachable("Buffer is not an ELF object file!");
if (EC)
return EC;
return std::move(R);
}
} // end namespace llvm