lib/Object/ELFObjectFile.cpp

   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 ELFObjectFileBase::ELFObjectFileBase(unsigned int Type,
  21                                      std::unique_ptr<MemoryBuffer> Source)
  22     : ObjectFile(Type, std::move(Source)) {}
  23
  24 ErrorOr<std::unique_ptr<ObjectFile>>
  25 ObjectFile::createELFObjectFile(std::unique_ptr<MemoryBuffer> &Obj) {
  26   std::pair<unsigned char, unsigned char> Ident =
  27       getElfArchType(Obj->getBuffer());
  28   std::size_t MaxAlignment =
  29     1ULL << countTrailingZeros(uintptr_t(Obj->getBufferStart()));
  30
  31   std::error_code EC;
  32   std::unique_ptr<ObjectFile> R;
  33   if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2LSB)
  34 #if !LLVM_IS_UNALIGNED_ACCESS_FAST
  35     if (MaxAlignment >= 4)
  36       R.reset(new ELFObjectFile<ELFType<support::little, 4, false>>(
  37           std::move(Obj), EC));
  38     else
  39 #endif
  40     if (MaxAlignment >= 2)
  41       R.reset(new ELFObjectFile<ELFType<support::little, 2, false>>(
  42           std::move(Obj), EC));
  43     else
  44       return object_error::parse_failed;
  45   else if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2MSB)
  46 #if !LLVM_IS_UNALIGNED_ACCESS_FAST
  47     if (MaxAlignment >= 4)
  48       R.reset(new ELFObjectFile<ELFType<support::big, 4, false>>(std::move(Obj),
  49                                                                  EC));
  50     else
  51 #endif
  52     if (MaxAlignment >= 2)
  53       R.reset(new ELFObjectFile<ELFType<support::big, 2, false>>(std::move(Obj),
  54                                                                  EC));
  55     else
  56       return object_error::parse_failed;
  57   else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2MSB)
  58 #if !LLVM_IS_UNALIGNED_ACCESS_FAST
  59     if (MaxAlignment >= 8)
  60       R.reset(new ELFObjectFile<ELFType<support::big, 8, true>>(std::move(Obj),
  61                                                                 EC));
  62     else
  63 #endif
  64     if (MaxAlignment >= 2)
  65       R.reset(new ELFObjectFile<ELFType<support::big, 2, true>>(std::move(Obj),
  66                                                                 EC));
  67     else
  68       return object_error::parse_failed;
  69   else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2LSB) {
  70 #if !LLVM_IS_UNALIGNED_ACCESS_FAST
  71     if (MaxAlignment >= 8)
  72       R.reset(new ELFObjectFile<ELFType<support::little, 8, true>>(
  73           std::move(Obj), EC));
  74     else
  75 #endif
  76     if (MaxAlignment >= 2)
  77       R.reset(new ELFObjectFile<ELFType<support::little, 2, true>>(
  78           std::move(Obj), EC));
  79     else
  80       return object_error::parse_failed;
  81   }
  82   else
  83     llvm_unreachable("Buffer is not an ELF object file!");
  84
  85   if (EC)
  86     return EC;
  87   return std::move(R);
  88 }
  89
  90 } // end namespace llvm