1//===- ELFObjectFile.cpp - ELF object file implementation -------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// Part of the ELFObjectFile class implementation.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Object/ELFObjectFile.h"
15#include "llvm/Support/MathExtras.h"
16
17namespace llvm {
18using namespace object;
19
20ELFObjectFileBase::ELFObjectFileBase(unsigned int Type, MemoryBufferRef Source)
21    : ObjectFile(Type, Source) {}
22
23ErrorOr<std::unique_ptr<ObjectFile>>
24ObjectFile::createELFObjectFile(MemoryBufferRef Obj) {
25  std::pair<unsigned char, unsigned char> Ident =
26      getElfArchType(Obj.getBuffer());
27  std::size_t MaxAlignment =
28      1ULL << countTrailingZeros(uintptr_t(Obj.getBufferStart()));
29
30  std::error_code EC;
31  std::unique_ptr<ObjectFile> R;
32  if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2LSB)
33#if !LLVM_IS_UNALIGNED_ACCESS_FAST
34    if (MaxAlignment >= 4)
35      R.reset(new ELFObjectFile<ELFType<support::little, 4, false>>(Obj, EC));
36    else
37#endif
38    if (MaxAlignment >= 2)
39      R.reset(new ELFObjectFile<ELFType<support::little, 2, false>>(Obj, EC));
40    else
41      return object_error::parse_failed;
42  else if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2MSB)
43#if !LLVM_IS_UNALIGNED_ACCESS_FAST
44    if (MaxAlignment >= 4)
45      R.reset(new ELFObjectFile<ELFType<support::big, 4, false>>(Obj, EC));
46    else
47#endif
48    if (MaxAlignment >= 2)
49      R.reset(new ELFObjectFile<ELFType<support::big, 2, false>>(Obj, EC));
50    else
51      return object_error::parse_failed;
52  else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2MSB)
53#if !LLVM_IS_UNALIGNED_ACCESS_FAST
54    if (MaxAlignment >= 8)
55      R.reset(new ELFObjectFile<ELFType<support::big, 8, true>>(Obj, EC));
56    else
57#endif
58    if (MaxAlignment >= 2)
59      R.reset(new ELFObjectFile<ELFType<support::big, 2, true>>(Obj, EC));
60    else
61      return object_error::parse_failed;
62  else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2LSB) {
63#if !LLVM_IS_UNALIGNED_ACCESS_FAST
64    if (MaxAlignment >= 8)
65      R.reset(new ELFObjectFile<ELFType<support::little, 8, true>>(Obj, EC));
66    else
67#endif
68    if (MaxAlignment >= 2)
69      R.reset(new ELFObjectFile<ELFType<support::little, 2, true>>(Obj, EC));
70    else
71      return object_error::parse_failed;
72  }
73  else
74    llvm_unreachable("Buffer is not an ELF object file!");
75
76  if (EC)
77    return EC;
78  return std::move(R);
79}
80
81} // end namespace llvm
82