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/Object/Archive.h"
18 #include "llvm/Support/Casting.h"
19 #include "llvm/Support/Host.h"
20 #include "llvm/Support/MemoryBuffer.h"
21 
22 using namespace llvm;
23 using namespace object;
24 
25 template<typename T>
26 static void SwapValue(T &Value) {
27   Value = sys::SwapByteOrder(Value);
28 }
29 
30 template<typename T>
31 static void SwapStruct(T &Value);
32 
33 template<>
34 void SwapStruct(MachO::fat_header &H) {
35   SwapValue(H.magic);
36   SwapValue(H.nfat_arch);
37 }
38 
39 template<>
40 void 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 
48 template<typename T>
49 static 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 
58 MachOUniversalBinary::ObjectForArch::ObjectForArch(
59     const MachOUniversalBinary *Parent, uint32_t Index)
60     : Parent(Parent), Index(Index) {
61   if (!Parent || 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 
75 error_code MachOUniversalBinary::ObjectForArch::getAsObjectFile(
76     std::unique_ptr<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     ErrorOr<ObjectFile *> Obj = ObjectFile::createMachOObjectFile(ObjBuffer);
86     if (error_code EC = Obj.getError())
87       return EC;
88     Result.reset(Obj.get());
89     return object_error::success;
90   }
91   return object_error::parse_failed;
92 }
93 
94 error_code MachOUniversalBinary::ObjectForArch::getAsArchive(
95     std::unique_ptr<Archive> &Result) const {
96   if (Parent) {
97     StringRef ParentData = Parent->getData();
98     StringRef ObjectData = ParentData.substr(Header.offset, Header.size);
99     std::string ObjectName =
100         Parent->getFileName().str() + ":" +
101         Triple::getArchTypeName(MachOObjectFile::getArch(Header.cputype));
102     MemoryBuffer *ObjBuffer = MemoryBuffer::getMemBuffer(
103         ObjectData, ObjectName, false);
104     ErrorOr<Archive *> Obj = Archive::create(ObjBuffer);
105     if (error_code EC = Obj.getError())
106       return EC;
107     Result.reset(Obj.get());
108     return object_error::success;
109   }
110   return object_error::parse_failed;
111 }
112 
113 void MachOUniversalBinary::anchor() { }
114 
115 ErrorOr<MachOUniversalBinary *>
116 MachOUniversalBinary::create(MemoryBuffer *Source) {
117   error_code EC;
118   std::unique_ptr<MachOUniversalBinary> Ret(
119       new MachOUniversalBinary(Source, EC));
120   if (EC)
121     return EC;
122   return Ret.release();
123 }
124 
125 MachOUniversalBinary::MachOUniversalBinary(MemoryBuffer *Source,
126                                            error_code &ec)
127   : Binary(Binary::ID_MachOUniversalBinary, Source),
128     NumberOfObjects(0) {
129   if (Source->getBufferSize() < sizeof(MachO::fat_header)) {
130     ec = object_error::invalid_file_type;
131     return;
132   }
133   // Check for magic value and sufficient header size.
134   StringRef Buf = getData();
135   MachO::fat_header H= getUniversalBinaryStruct<MachO::fat_header>(Buf.begin());
136   NumberOfObjects = H.nfat_arch;
137   uint32_t MinSize = sizeof(MachO::fat_header) +
138                      sizeof(MachO::fat_arch) * NumberOfObjects;
139   if (H.magic != MachO::FAT_MAGIC || Buf.size() < MinSize) {
140     ec = object_error::parse_failed;
141     return;
142   }
143   ec = object_error::success;
144 }
145 
146 static bool getCTMForArch(Triple::ArchType Arch, MachO::CPUType &CTM) {
147   switch (Arch) {
148     case Triple::x86:    CTM = MachO::CPU_TYPE_I386; return true;
149     case Triple::x86_64: CTM = MachO::CPU_TYPE_X86_64; return true;
150     case Triple::arm:    CTM = MachO::CPU_TYPE_ARM; return true;
151     case Triple::sparc:  CTM = MachO::CPU_TYPE_SPARC; return true;
152     case Triple::ppc:    CTM = MachO::CPU_TYPE_POWERPC; return true;
153     case Triple::ppc64:  CTM = MachO::CPU_TYPE_POWERPC64; return true;
154     default: return false;
155   }
156 }
157 
158 error_code MachOUniversalBinary::getObjectForArch(
159     Triple::ArchType Arch, std::unique_ptr<ObjectFile> &Result) const {
160   MachO::CPUType CTM;
161   if (!getCTMForArch(Arch, CTM))
162     return object_error::arch_not_found;
163   for (object_iterator I = begin_objects(), E = end_objects(); I != E; ++I) {
164     if (I->getCPUType() == static_cast<uint32_t>(CTM))
165       return I->getAsObjectFile(Result);
166   }
167   return object_error::arch_not_found;
168 }
169