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 ErrorOr<ObjectFile *> ObjectFile::createELFObjectFile(MemoryBuffer *Obj,
  21                                                       bool BufferOwned) {
  22   std::pair<unsigned char, unsigned char> Ident = getElfArchType(Obj);
  23   std::size_t MaxAlignment =
  24     1ULL << countTrailingZeros(uintptr_t(Obj->getBufferStart()));
  25
  26   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, EC, BufferOwned));
  33     else
  34 #endif
  35     if (MaxAlignment >= 2)
  36       R.reset(new ELFObjectFile<ELFType<support::little, 2, false> >(
  37           Obj, EC, BufferOwned));
  38     else
  39       llvm_unreachable("Invalid alignment for ELF file!");
  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, EC,
  44                                                                   BufferOwned));
  45     else
  46 #endif
  47     if (MaxAlignment >= 2)
  48       R.reset(new ELFObjectFile<ELFType<support::big, 2, false> >(Obj, EC,
  49                                                                   BufferOwned));
  50     else
  51       llvm_unreachable("Invalid alignment for ELF file!");
  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                                                                  BufferOwned));
  57     else
  58 #endif
  59     if (MaxAlignment >= 2)
  60       R.reset(new ELFObjectFile<ELFType<support::big, 2, true> >(Obj, EC,
  61                                                                  BufferOwned));
  62     else
  63       llvm_unreachable("Invalid alignment for ELF file!");
  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, EC, BufferOwned));
  69     else
  70 #endif
  71     if (MaxAlignment >= 2)
  72       R.reset(new ELFObjectFile<ELFType<support::little, 2, true> >(
  73           Obj, EC, BufferOwned));
  74     else
  75       llvm_unreachable("Invalid alignment for ELF file!");
  76   }
  77   else
  78     report_fatal_error("Buffer is not an ELF object file!");
  79
  80   if (EC)
  81     return EC;
  82   return R.release();
  83 }
  84
  85 } // end namespace llvm