MachOUniversal.cpp revision 261991 
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
16#include "llvm/Object/MachO.h"
17#include "llvm/Object/ObjectFile.h"
18#include "llvm/Support/Casting.h"
19#include "llvm/Support/Host.h"
20#include "llvm/Support/MemoryBuffer.h"
21
22using namespace llvm;
23using namespace object;
24
25template<typename T>
26static void SwapValue(T &Value) {
27  Value = sys::SwapByteOrder(Value);
28}
29
30template<typename T>
31static void SwapStruct(T &Value);
32
33template<>
34void SwapStruct(MachO::fat_header &H) {
35  SwapValue(H.magic);
36  SwapValue(H.nfat_arch);
37}
38
39template<>
40void SwapStruct(MachO::fat_arch &H) {
41  SwapValue(H.cputype);
42  SwapValue(H.cpusubtype);
43  SwapValue(H.offset);
44  SwapValue(H.size);
45  SwapValue(H.align);
46}
47
48template<typename T>
49static T getUniversalBinaryStruct(const char *Ptr) {
50  T Res;
51  memcpy(&Res, Ptr, sizeof(T));
52  // Universal binary headers have big-endian byte order.
53  if (sys::IsLittleEndianHost)
54    SwapStruct(Res);
55  return Res;
56}
57
58MachOUniversalBinary::ObjectForArch::ObjectForArch(
59    const MachOUniversalBinary *Parent, uint32_t Index)
60    : Parent(Parent), Index(Index) {
61  if (Parent == 0 || Index > Parent->getNumberOfObjects()) {
62    clear();
63  } else {
64    // Parse object header.
65    StringRef ParentData = Parent->getData();
66    const char *HeaderPos = ParentData.begin() + sizeof(MachO::fat_header) +
67                            Index * sizeof(MachO::fat_arch);
68    Header = getUniversalBinaryStruct<MachO::fat_arch>(HeaderPos);
69    if (ParentData.size() < Header.offset + Header.size) {
70      clear();
71    }
72  }
73}
74
75error_code MachOUniversalBinary::ObjectForArch::getAsObjectFile(
76    OwningPtr<ObjectFile> &Result) const {
77  if (Parent) {
78    StringRef ParentData = Parent->getData();
79    StringRef ObjectData = ParentData.substr(Header.offset, Header.size);
80    std::string ObjectName =
81        Parent->getFileName().str() + ":" +
82        Triple::getArchTypeName(MachOObjectFile::getArch(Header.cputype));
83    MemoryBuffer *ObjBuffer = MemoryBuffer::getMemBuffer(
84        ObjectData, ObjectName, false);
85    if (ObjectFile *Obj = ObjectFile::createMachOObjectFile(ObjBuffer)) {
86      Result.reset(Obj);
87      return object_error::success;
88    }
89  }
90  return object_error::parse_failed;
91}
92
93void MachOUniversalBinary::anchor() { }
94
95MachOUniversalBinary::MachOUniversalBinary(MemoryBuffer *Source,
96                                           error_code &ec)
97  : Binary(Binary::ID_MachOUniversalBinary, Source),
98    NumberOfObjects(0) {
99  if (Source->getBufferSize() < sizeof(MachO::fat_header)) {
100    ec = object_error::invalid_file_type;
101    return;
102  }
103  // Check for magic value and sufficient header size.
104  StringRef Buf = getData();
105  MachO::fat_header H= getUniversalBinaryStruct<MachO::fat_header>(Buf.begin());
106  NumberOfObjects = H.nfat_arch;
107  uint32_t MinSize = sizeof(MachO::fat_header) +
108                     sizeof(MachO::fat_arch) * NumberOfObjects;
109  if (H.magic != MachO::FAT_MAGIC || Buf.size() < MinSize) {
110    ec = object_error::parse_failed;
111    return;
112  }
113  ec = object_error::success;
114}
115
116static bool getCTMForArch(Triple::ArchType Arch, MachO::CPUType &CTM) {
117  switch (Arch) {
118    case Triple::x86:    CTM = MachO::CPU_TYPE_I386; return true;
119    case Triple::x86_64: CTM = MachO::CPU_TYPE_X86_64; return true;
120    case Triple::arm:    CTM = MachO::CPU_TYPE_ARM; return true;
121    case Triple::sparc:  CTM = MachO::CPU_TYPE_SPARC; return true;
122    case Triple::ppc:    CTM = MachO::CPU_TYPE_POWERPC; return true;
123    case Triple::ppc64:  CTM = MachO::CPU_TYPE_POWERPC64; return true;
124    default: return false;
125  }
126}
127
128error_code
129MachOUniversalBinary::getObjectForArch(Triple::ArchType Arch,
130                                       OwningPtr<ObjectFile> &Result) const {
131  MachO::CPUType CTM;
132  if (!getCTMForArch(Arch, CTM))
133    return object_error::arch_not_found;
134  for (object_iterator I = begin_objects(), E = end_objects(); I != E; ++I) {
135    if (I->getCPUType() == static_cast<uint32_t>(CTM))
136      return I->getAsObjectFile(Result);
137  }
138  return object_error::arch_not_found;
139}
140