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      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 
     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::FatHeader &H) {
     35   SwapValue(H.Magic);
     36   SwapValue(H.NumFatArch);
     37 }
     38 
     39 template<>
     40 void SwapStruct(macho::FatArchHeader &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 == 0 || Index > Parent->getNumberOfObjects()) {
     62     clear();
     63   } else {
     64     // Parse object header.
     65     StringRef ParentData = Parent->getData();
     66     const char *HeaderPos = ParentData.begin() + macho::FatHeaderSize +
     67                             Index * macho::FatArchHeaderSize;
     68     Header = getUniversalBinaryStruct<macho::FatArchHeader>(HeaderPos);
     69     if (ParentData.size() < Header.Offset + Header.Size) {
     70       clear();
     71     }
     72   }
     73 }
     74 
     75 error_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 
     93 void MachOUniversalBinary::anchor() { }
     94 
     95 MachOUniversalBinary::MachOUniversalBinary(MemoryBuffer *Source,
     96                                            error_code &ec)
     97   : Binary(Binary::ID_MachOUniversalBinary, Source),
     98     NumberOfObjects(0) {
     99   if (Source->getBufferSize() < macho::FatHeaderSize) {
    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::FatHeader H = getUniversalBinaryStruct<macho::FatHeader>(Buf.begin());
    106   NumberOfObjects = H.NumFatArch;
    107   uint32_t MinSize = macho::FatHeaderSize +
    108                      macho::FatArchHeaderSize * NumberOfObjects;
    109   if (H.Magic != macho::HM_Universal || Buf.size() < MinSize) {
    110     ec = object_error::parse_failed;
    111     return;
    112   }
    113   ec = object_error::success;
    114 }
    115 
    116 static bool getCTMForArch(Triple::ArchType Arch, mach::CPUTypeMachine &CTM) {
    117   switch (Arch) {
    118     case Triple::x86:    CTM = mach::CTM_i386; return true;
    119     case Triple::x86_64: CTM = mach::CTM_x86_64; return true;
    120     case Triple::arm:    CTM = mach::CTM_ARM; return true;
    121     case Triple::sparc:  CTM = mach::CTM_SPARC; return true;
    122     case Triple::ppc:    CTM = mach::CTM_PowerPC; return true;
    123     case Triple::ppc64:  CTM = mach::CTM_PowerPC64; return true;
    124     default: return false;
    125   }
    126 }
    127 
    128 error_code
    129 MachOUniversalBinary::getObjectForArch(Triple::ArchType Arch,
    130                                        OwningPtr<ObjectFile> &Result) const {
    131   mach::CPUTypeMachine 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