path: root/lib/Object/ELFObjectFile.cpp

//===- 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.
//
//===----------------------------------------------------------------------===//
//
// This file defines the ELFObjectFile class.
//
//===----------------------------------------------------------------------===//

#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/ADT/Triple.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MemoryBuffer.h"
#include <limits>
#include <utility>

using namespace llvm;
using namespace object;

// Templates to choose Elf_Addr and Elf_Off depending on is64Bits.
namespace {
template<support::endianness target_endianness>
struct ELFDataTypeTypedefHelperCommon {
  typedef support::detail::packed_endian_specific_integral
    <uint16_t, target_endianness, support::aligned> Elf_Half;
  typedef support::detail::packed_endian_specific_integral
    <uint32_t, target_endianness, support::aligned> Elf_Word;
  typedef support::detail::packed_endian_specific_integral
    <int32_t, target_endianness, support::aligned> Elf_Sword;
  typedef support::detail::packed_endian_specific_integral
    <uint64_t, target_endianness, support::aligned> Elf_Xword;
  typedef support::detail::packed_endian_specific_integral
    <int64_t, target_endianness, support::aligned> Elf_Sxword;
};
}

namespace {
template<support::endianness target_endianness, bool is64Bits>
struct ELFDataTypeTypedefHelper;

/// ELF 32bit types.
template<support::endianness target_endianness>
struct ELFDataTypeTypedefHelper<target_endianness, false>
  : ELFDataTypeTypedefHelperCommon<target_endianness> {
  typedef support::detail::packed_endian_specific_integral
    <uint32_t, target_endianness, support::aligned> Elf_Addr;
  typedef support::detail::packed_endian_specific_integral
    <uint32_t, target_endianness, support::aligned> Elf_Off;
};

/// ELF 64bit types.
template<support::endianness target_endianness>
struct ELFDataTypeTypedefHelper<target_endianness, true>
  : ELFDataTypeTypedefHelperCommon<target_endianness>{
  typedef support::detail::packed_endian_specific_integral
    <uint64_t, target_endianness, support::aligned> Elf_Addr;
  typedef support::detail::packed_endian_specific_integral
    <uint64_t, target_endianness, support::aligned> Elf_Off;
};
}

// I really don't like doing this, but the alternative is copypasta.
#define LLVM_ELF_IMPORT_TYPES(target_endianness, is64Bits) \
typedef typename \
  ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Addr Elf_Addr; \
typedef typename \
  ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Off Elf_Off; \
typedef typename \
  ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Half Elf_Half; \
typedef typename \
  ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Word Elf_Word; \
typedef typename \
  ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Sword Elf_Sword; \
typedef typename \
  ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Xword Elf_Xword; \
typedef typename \
  ELFDataTypeTypedefHelper<target_endianness, is64Bits>::Elf_Sxword Elf_Sxword;

  // Section header.
namespace {
template<support::endianness target_endianness, bool is64Bits>
struct Elf_Shdr_Base;

template<support::endianness target_endianness>
struct Elf_Shdr_Base<target_endianness, false> {
  LLVM_ELF_IMPORT_TYPES(target_endianness, false)
  Elf_Word sh_name;     // Section name (index into string table)
  Elf_Word sh_type;     // Section type (SHT_*)
  Elf_Word sh_flags;    // Section flags (SHF_*)
  Elf_Addr sh_addr;     // Address where section is to be loaded
  Elf_Off  sh_offset;   // File offset of section data, in bytes
  Elf_Word sh_size;     // Size of section, in bytes
  Elf_Word sh_link;     // Section type-specific header table index link
  Elf_Word sh_info;     // Section type-specific extra information
  Elf_Word sh_addralign;// Section address alignment
  Elf_Word sh_entsize;  // Size of records contained within the section
};

template<support::endianness target_endianness>
struct Elf_Shdr_Base<target_endianness, true> {
  LLVM_ELF_IMPORT_TYPES(target_endianness, true)
  Elf_Word  sh_name;     // Section name (index into string table)
  Elf_Word  sh_type;     // Section type (SHT_*)
  Elf_Xword sh_flags;    // Section flags (SHF_*)
  Elf_Addr  sh_addr;     // Address where section is to be loaded
  Elf_Off   sh_offset;   // File offset of section data, in bytes
  Elf_Xword sh_size;     // Size of section, in bytes
  Elf_Word  sh_link;     // Section type-specific header table index link
  Elf_Word  sh_info;     // Section type-specific extra information
  Elf_Xword sh_addralign;// Section address alignment