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 
ELFObjectFileBase(unsigned int Type,MemoryBufferRef Source)20 ELFObjectFileBase::ELFObjectFileBase(unsigned int Type, MemoryBufferRef Source)
21     : ObjectFile(Type, Source) {}
22 
23 ErrorOr<std::unique_ptr<ObjectFile>>
createELFObjectFile(MemoryBufferRef Obj)24 ObjectFile::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