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 
17 namespace llvm {
18 using namespace object;
19 
20 ErrorOr<ObjectFile *>
21 ObjectFile::createELFObjectFile(std::unique_ptr<MemoryBuffer> &Obj) {
22   std::pair<unsigned char, unsigned char> Ident = getElfArchType(Obj.get());
23   std::size_t MaxAlignment =
24     1ULL << countTrailingZeros(uintptr_t(Obj->getBufferStart()));
25 
26   std::error_code EC;
27   std::unique_ptr<ObjectFile> R;
28   if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2LSB)
29 #if !LLVM_IS_UNALIGNED_ACCESS_FAST
30     if (MaxAlignment >= 4)
31       R.reset(new ELFObjectFile<ELFType<support::little, 4, false>>(
32           Obj.release(), EC));
33     else
34 #endif
35     if (MaxAlignment >= 2)
36       R.reset(new ELFObjectFile<ELFType<support::little, 2, false>>(
37           Obj.release(), EC));
38     else
39       return object_error::parse_failed;
40   else if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2MSB)
41 #if !LLVM_IS_UNALIGNED_ACCESS_FAST
42     if (MaxAlignment >= 4)
43       R.reset(new ELFObjectFile<ELFType<support::big, 4, false>>(Obj.release(),
44                                                                  EC));
45     else
46 #endif
47     if (MaxAlignment >= 2)
48       R.reset(new ELFObjectFile<ELFType<support::big, 2, false>>(Obj.release(),
49                                                                  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(
56           new ELFObjectFile<ELFType<support::big, 8, true>>(Obj.release(), EC));
57     else
58 #endif
59     if (MaxAlignment >= 2)
60       R.reset(
61           new ELFObjectFile<ELFType<support::big, 2, true>>(Obj.release(), EC));
62     else
63       return object_error::parse_failed;
64   else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2LSB) {
65 #if !LLVM_IS_UNALIGNED_ACCESS_FAST
66     if (MaxAlignment >= 8)
67       R.reset(new ELFObjectFile<ELFType<support::little, 8, true>>(
68           Obj.release(), EC));
69     else
70 #endif
71     if (MaxAlignment >= 2)
72       R.reset(new ELFObjectFile<ELFType<support::little, 2, true>>(
73           Obj.release(), EC));
74     else
75       return object_error::parse_failed;
76   }
77   else
78     llvm_unreachable("Buffer is not an ELF object file!");
79 
80   if (EC)
81     return EC;
82   return R.release();
83 }
84 
85 } // end namespace llvm
86