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 SwapStruct(T &Value);
27 
28 template<>
29 void SwapStruct(MachO::fat_header &H) {
30   sys::swapByteOrder(H.magic);
31   sys::swapByteOrder(H.nfat_arch);
32 }
33 
34 template<>
35 void SwapStruct(MachO::fat_arch &H) {
36   sys::swapByteOrder(H.cputype);
37   sys::swapByteOrder(H.cpusubtype);
38   sys::swapByteOrder(H.offset);
39   sys::swapByteOrder(H.size);
40   sys::swapByteOrder(H.align);
41 }
42 
43 template<typename T>
44 static T getUniversalBinaryStruct(const char *Ptr) {
45   T Res;
46   memcpy(&Res, Ptr, sizeof(T));
47   // Universal binary headers have big-endian byte order.
48   if (sys::IsLittleEndianHost)
49     SwapStruct(Res);
50   return Res;
51 }
52 
53 MachOUniversalBinary::ObjectForArch::ObjectForArch(
54     const MachOUniversalBinary *Parent, uint32_t Index)
55     : Parent(Parent), Index(Index) {
56   if (!Parent || Index >= Parent->getNumberOfObjects()) {
57     clear();
58   } else {
59     // Parse object header.
60     StringRef ParentData = Parent->getData();
61     const char *HeaderPos = ParentData.begin() + sizeof(MachO::fat_header) +
62                             Index * sizeof(MachO::fat_arch);
63     Header = getUniversalBinaryStruct<MachO::fat_arch>(HeaderPos);
64     if (ParentData.size() < Header.offset + Header.size) {
65       clear();
66     }
67   }
68 }
69 
70 ErrorOr<std::unique_ptr<ObjectFile>>
71 MachOUniversalBinary::ObjectForArch::getAsObjectFile() const {
72   if (Parent) {
73     StringRef ParentData = Parent->getData();
74     StringRef ObjectData = ParentData.substr(Header.offset, Header.size);
75     std::string ObjectName = Parent->getFileName().str();
76     std::unique_ptr<MemoryBuffer> ObjBuffer(
77         MemoryBuffer::getMemBuffer(ObjectData, ObjectName, false));
78     return ObjectFile::createMachOObjectFile(ObjBuffer);
79   }
80   return object_error::parse_failed;
81 }
82 
83 std::error_code MachOUniversalBinary::ObjectForArch::getAsArchive(
84     std::unique_ptr<Archive> &Result) const {
85   if (Parent) {
86     StringRef ParentData = Parent->getData();
87     StringRef ObjectData = ParentData.substr(Header.offset, Header.size);
88     std::string ObjectName = Parent->getFileName().str();
89     std::unique_ptr<MemoryBuffer> ObjBuffer(
90         MemoryBuffer::getMemBuffer(ObjectData, ObjectName, false));
91     ErrorOr<std::unique_ptr<Archive>> Obj =
92         Archive::create(std::move(ObjBuffer));
93     if (std::error_code EC = Obj.getError())
94       return EC;
95     Result = std::move(Obj.get());
96     return object_error::success;
97   }
98   return object_error::parse_failed;
99 }
100 
101 void MachOUniversalBinary::anchor() { }
102 
103 ErrorOr<MachOUniversalBinary *>
104 MachOUniversalBinary::create(std::unique_ptr<MemoryBuffer> Source) {
105   std::error_code EC;
106   std::unique_ptr<MachOUniversalBinary> Ret(
107       new MachOUniversalBinary(std::move(Source), EC));
108   if (EC)
109     return EC;
110   return Ret.release();
111 }
112 
113 MachOUniversalBinary::MachOUniversalBinary(std::unique_ptr<MemoryBuffer> Source,
114                                            std::error_code &ec)
115     : Binary(Binary::ID_MachOUniversalBinary, std::move(Source)),
116       NumberOfObjects(0) {
117   if (Data->getBufferSize() < sizeof(MachO::fat_header)) {
118     ec = object_error::invalid_file_type;
119     return;
120   }
121   // Check for magic value and sufficient header size.
122   StringRef Buf = getData();
123   MachO::fat_header H= getUniversalBinaryStruct<MachO::fat_header>(Buf.begin());
124   NumberOfObjects = H.nfat_arch;
125   uint32_t MinSize = sizeof(MachO::fat_header) +
126                      sizeof(MachO::fat_arch) * NumberOfObjects;
127   if (H.magic != MachO::FAT_MAGIC || Buf.size() < MinSize) {
128     ec = object_error::parse_failed;
129     return;
130   }
131   ec = object_error::success;
132 }
133 
134 static bool getCTMForArch(Triple::ArchType Arch, MachO::CPUType &CTM) {
135   switch (Arch) {
136     case Triple::x86:    CTM = MachO::CPU_TYPE_I386; return true;
137     case Triple::x86_64: CTM = MachO::CPU_TYPE_X86_64; return true;
138     case Triple::arm:    CTM = MachO::CPU_TYPE_ARM; return true;
139     case Triple::sparc:  CTM = MachO::CPU_TYPE_SPARC; return true;
140     case Triple::ppc:    CTM = MachO::CPU_TYPE_POWERPC; return true;
141     case Triple::ppc64:  CTM = MachO::CPU_TYPE_POWERPC64; return true;
142     default: return false;
143   }
144 }
145 
146 ErrorOr<std::unique_ptr<ObjectFile>>
147 MachOUniversalBinary::getObjectForArch(Triple::ArchType Arch) const {
148   MachO::CPUType CTM;
149   if (!getCTMForArch(Arch, CTM))
150     return object_error::arch_not_found;
151   for (object_iterator I = begin_objects(), E = end_objects(); I != E; ++I) {
152     if (I->getCPUType() == static_cast<uint32_t>(CTM))
153       return I->getAsObjectFile();
154   }
155   return object_error::arch_not_found;
156 }
157