MachOUniversal.cpp revision 36b56886974eae4f9c5ebc96befd3e7bfe5de338 
1//===- MachOUniversal.cpp - Mach-O universal binary -------------*- 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// This file defines the MachOUniversalBinary class.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Object/MachOUniversal.h"
15#include "llvm/Object/MachO.h"
16#include "llvm/Object/ObjectFile.h"
17#include "llvm/Support/Casting.h"
18#include "llvm/Support/Host.h"
19#include "llvm/Support/MemoryBuffer.h"
20
21using namespace llvm;
22using namespace object;
23
24template<typename T>
25static void SwapValue(T &Value) {
26  Value = sys::SwapByteOrder(Value);
27}
28
29template<typename T>
30static void SwapStruct(T &Value);
31
32template<>
33void SwapStruct(MachO::fat_header &H) {
34  SwapValue(H.magic);
35  SwapValue(H.nfat_arch);
36}
37
38template<>
39void SwapStruct(MachO::fat_arch &H) {
40  SwapValue(H.cputype);
41  SwapValue(H.cpusubtype);
42  SwapValue(H.offset);
43  SwapValue(H.size);
44  SwapValue(H.align);
45}
46
47template<typename T>
48static T getUniversalBinaryStruct(const char *Ptr) {
49  T Res;
50  memcpy(&Res, Ptr, sizeof(T));
51  // Universal binary headers have big-endian byte order.
52  if (sys::IsLittleEndianHost)
53    SwapStruct(Res);
54  return Res;
55}
56
57MachOUniversalBinary::ObjectForArch::ObjectForArch(
58    const MachOUniversalBinary *Parent, uint32_t Index)
59    : Parent(Parent), Index(Index) {
60  if (Parent == 0 || Index > Parent->getNumberOfObjects()) {
61    clear();
62  } else {
63    // Parse object header.
64    StringRef ParentData = Parent->getData();
65    const char *HeaderPos = ParentData.begin() + sizeof(MachO::fat_header) +
66                            Index * sizeof(MachO::fat_arch);
67    Header = getUniversalBinaryStruct<MachO::fat_arch>(HeaderPos);
68    if (ParentData.size() < Header.offset + Header.size) {
69      clear();
70    }
71  }
72}
73
74error_code MachOUniversalBinary::ObjectForArch::getAsObjectFile(
75    std::unique_ptr<ObjectFile> &Result) const {
76  if (Parent) {
77    StringRef ParentData = Parent->getData();
78    StringRef ObjectData = ParentData.substr(Header.offset, Header.size);
79    std::string ObjectName =
80        Parent->getFileName().str() + ":" +
81        Triple::getArchTypeName(MachOObjectFile::getArch(Header.cputype));
82    MemoryBuffer *ObjBuffer = MemoryBuffer::getMemBuffer(
83        ObjectData, ObjectName, false);
84    ErrorOr<ObjectFile *> Obj = ObjectFile::createMachOObjectFile(ObjBuffer);
85    if (error_code EC = Obj.getError())
86      return EC;
87    Result.reset(Obj.get());
88    return object_error::success;
89  }
90  return object_error::parse_failed;
91}
92
93void MachOUniversalBinary::anchor() { }
94
95ErrorOr<MachOUniversalBinary *>
96MachOUniversalBinary::create(MemoryBuffer *Source) {
97  error_code EC;
98  std::unique_ptr<MachOUniversalBinary> Ret(
99      new MachOUniversalBinary(Source, EC));
100  if (EC)
101    return EC;
102  return Ret.release();
103}
104
105MachOUniversalBinary::MachOUniversalBinary(MemoryBuffer *Source,
106                                           error_code &ec)
107  : Binary(Binary::ID_MachOUniversalBinary, Source),
108    NumberOfObjects(0) {
109  if (Source->getBufferSize() < sizeof(MachO::fat_header)) {
110    ec = object_error::invalid_file_type;
111    return;
112  }
113  // Check for magic value and sufficient header size.
114  StringRef Buf = getData();
115  MachO::fat_header H= getUniversalBinaryStruct<MachO::fat_header>(Buf.begin());
116  NumberOfObjects = H.nfat_arch;
117  uint32_t MinSize = sizeof(MachO::fat_header) +
118                     sizeof(MachO::fat_arch) * NumberOfObjects;
119  if (H.magic != MachO::FAT_MAGIC || Buf.size() < MinSize) {
120    ec = object_error::parse_failed;
121    return;
122  }
123  ec = object_error::success;
124}
125
126static bool getCTMForArch(Triple::ArchType Arch, MachO::CPUType &CTM) {
127  switch (Arch) {
128    case Triple::x86:    CTM = MachO::CPU_TYPE_I386; return true;
129    case Triple::x86_64: CTM = MachO::CPU_TYPE_X86_64; return true;
130    case Triple::arm:    CTM = MachO::CPU_TYPE_ARM; return true;
131    case Triple::sparc:  CTM = MachO::CPU_TYPE_SPARC; return true;
132    case Triple::ppc:    CTM = MachO::CPU_TYPE_POWERPC; return true;
133    case Triple::ppc64:  CTM = MachO::CPU_TYPE_POWERPC64; return true;
134    default: return false;
135  }
136}
137
138error_code MachOUniversalBinary::getObjectForArch(
139    Triple::ArchType Arch, std::unique_ptr<ObjectFile> &Result) const {
140  MachO::CPUType CTM;
141  if (!getCTMForArch(Arch, CTM))
142    return object_error::arch_not_found;
143  for (object_iterator I = begin_objects(), E = end_objects(); I != E; ++I) {
144    if (I->getCPUType() == static_cast<uint32_t>(CTM))
145      return I->getAsObjectFile(Result);
146  }
147  return object_error::arch_not_found;
148}
149