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/ELF.h"
15#include "llvm/Support/MathExtras.h"
16
17#include <ctype.h>
18
19namespace llvm {
20
21using namespace object;
22
23// Creates an in-memory object-file by default: createELFObjectFile(Buffer)
24ObjectFile *ObjectFile::createELFObjectFile(MemoryBuffer *Object) {
25  std::pair<unsigned char, unsigned char> Ident = getElfArchType(Object);
26  error_code ec;
27
28  std::size_t MaxAlignment =
29    1ULL << CountTrailingZeros_64(uintptr_t(Object->getBufferStart()));
30
31  if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2LSB)
32#if !LLVM_IS_UNALIGNED_ACCESS_FAST
33    if (MaxAlignment >= 4)
34      return new ELFObjectFile<ELFType<support::little, 4, false> >(Object, ec);
35    else
36#endif
37    if (MaxAlignment >= 2)
38      return new ELFObjectFile<ELFType<support::little, 2, false> >(Object, ec);
39    else
40      llvm_unreachable("Invalid alignment for ELF file!");
41  else if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2MSB)
42#if !LLVM_IS_UNALIGNED_ACCESS_FAST
43    if (MaxAlignment >= 4)
44      return new ELFObjectFile<ELFType<support::big, 4, false> >(Object, ec);
45    else
46#endif
47    if (MaxAlignment >= 2)
48      return new ELFObjectFile<ELFType<support::big, 2, false> >(Object, ec);
49    else
50      llvm_unreachable("Invalid alignment for ELF file!");
51  else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2MSB)
52#if !LLVM_IS_UNALIGNED_ACCESS_FAST
53    if (MaxAlignment >= 8)
54      return new ELFObjectFile<ELFType<support::big, 8, true> >(Object, ec);
55    else
56#endif
57    if (MaxAlignment >= 2)
58      return new ELFObjectFile<ELFType<support::big, 2, true> >(Object, ec);
59    else
60      llvm_unreachable("Invalid alignment for ELF file!");
61  else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2LSB) {
62#if !LLVM_IS_UNALIGNED_ACCESS_FAST
63    if (MaxAlignment >= 8)
64      return new ELFObjectFile<ELFType<support::little, 8, true> >(Object, ec);
65    else
66#endif
67    if (MaxAlignment >= 2)
68      return new ELFObjectFile<ELFType<support::little, 2, true> >(Object, ec);
69    else
70      llvm_unreachable("Invalid alignment for ELF file!");
71  }
72
73  report_fatal_error("Buffer is not an ELF object file!");
74}
75
76} // end namespace llvm
77