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      1 //===- MachOObjectFile.cpp - Mach-O object file binding ---------*- 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 MachOObjectFile class, which binds the MachOObject
     11 // class to the generic ObjectFile wrapper.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "llvm/Object/MachO.h"
     16 #include "llvm/ADT/STLExtras.h"
     17 #include "llvm/ADT/Triple.h"
     18 #include "llvm/Support/DataExtractor.h"
     19 #include "llvm/Support/Format.h"
     20 #include "llvm/Support/Host.h"
     21 #include "llvm/Support/MemoryBuffer.h"
     22 #include "llvm/Support/raw_ostream.h"
     23 #include <cctype>
     24 #include <cstring>
     25 #include <limits>
     26 
     27 using namespace llvm;
     28 using namespace object;
     29 
     30 namespace llvm {
     31 
     32 namespace object {
     33 
     34 struct nlist_base {
     35   uint32_t n_strx;
     36   uint8_t n_type;
     37   uint8_t n_sect;
     38   uint16_t n_desc;
     39 };
     40 
     41 struct section_base {
     42   char sectname[16];
     43   char segname[16];
     44 };
     45 
     46 template<typename T>
     47 static void SwapStruct(T &Value);
     48 
     49 template<>
     50 void SwapStruct(MachO::any_relocation_info &H) {
     51   sys::swapByteOrder(H.r_word0);
     52   sys::swapByteOrder(H.r_word1);
     53 }
     54 
     55 template<>
     56 void SwapStruct(MachO::load_command &L) {
     57   sys::swapByteOrder(L.cmd);
     58   sys::swapByteOrder(L.cmdsize);
     59 }
     60 
     61 template<>
     62 void SwapStruct(nlist_base &S) {
     63   sys::swapByteOrder(S.n_strx);
     64   sys::swapByteOrder(S.n_desc);
     65 }
     66 
     67 template<>
     68 void SwapStruct(MachO::section &S) {
     69   sys::swapByteOrder(S.addr);
     70   sys::swapByteOrder(S.size);
     71   sys::swapByteOrder(S.offset);
     72   sys::swapByteOrder(S.align);
     73   sys::swapByteOrder(S.reloff);
     74   sys::swapByteOrder(S.nreloc);
     75   sys::swapByteOrder(S.flags);
     76   sys::swapByteOrder(S.reserved1);
     77   sys::swapByteOrder(S.reserved2);
     78 }
     79 
     80 template<>
     81 void SwapStruct(MachO::section_64 &S) {
     82   sys::swapByteOrder(S.addr);
     83   sys::swapByteOrder(S.size);
     84   sys::swapByteOrder(S.offset);
     85   sys::swapByteOrder(S.align);
     86   sys::swapByteOrder(S.reloff);
     87   sys::swapByteOrder(S.nreloc);
     88   sys::swapByteOrder(S.flags);
     89   sys::swapByteOrder(S.reserved1);
     90   sys::swapByteOrder(S.reserved2);
     91   sys::swapByteOrder(S.reserved3);
     92 }
     93 
     94 template<>
     95 void SwapStruct(MachO::nlist &S) {
     96   sys::swapByteOrder(S.n_strx);
     97   sys::swapByteOrder(S.n_desc);
     98   sys::swapByteOrder(S.n_value);
     99 }
    100 
    101 template<>
    102 void SwapStruct(MachO::nlist_64 &S) {
    103   sys::swapByteOrder(S.n_strx);
    104   sys::swapByteOrder(S.n_desc);
    105   sys::swapByteOrder(S.n_value);
    106 }
    107 
    108 template<>
    109 void SwapStruct(MachO::mach_header &H) {
    110   sys::swapByteOrder(H.magic);
    111   sys::swapByteOrder(H.cputype);
    112   sys::swapByteOrder(H.cpusubtype);
    113   sys::swapByteOrder(H.filetype);
    114   sys::swapByteOrder(H.ncmds);
    115   sys::swapByteOrder(H.sizeofcmds);
    116   sys::swapByteOrder(H.flags);
    117 }
    118 
    119 template<>
    120 void SwapStruct(MachO::mach_header_64 &H) {
    121   sys::swapByteOrder(H.magic);
    122   sys::swapByteOrder(H.cputype);
    123   sys::swapByteOrder(H.cpusubtype);
    124   sys::swapByteOrder(H.filetype);
    125   sys::swapByteOrder(H.ncmds);
    126   sys::swapByteOrder(H.sizeofcmds);
    127   sys::swapByteOrder(H.flags);
    128   sys::swapByteOrder(H.reserved);
    129 }
    130 
    131 template<>
    132 void SwapStruct(MachO::symtab_command &C) {
    133   sys::swapByteOrder(C.cmd);
    134   sys::swapByteOrder(C.cmdsize);
    135   sys::swapByteOrder(C.symoff);
    136   sys::swapByteOrder(C.nsyms);
    137   sys::swapByteOrder(C.stroff);
    138   sys::swapByteOrder(C.strsize);
    139 }
    140 
    141 template<>
    142 void SwapStruct(MachO::dysymtab_command &C) {
    143   sys::swapByteOrder(C.cmd);
    144   sys::swapByteOrder(C.cmdsize);
    145   sys::swapByteOrder(C.ilocalsym);
    146   sys::swapByteOrder(C.nlocalsym);
    147   sys::swapByteOrder(C.iextdefsym);
    148   sys::swapByteOrder(C.nextdefsym);
    149   sys::swapByteOrder(C.iundefsym);
    150   sys::swapByteOrder(C.nundefsym);
    151   sys::swapByteOrder(C.tocoff);
    152   sys::swapByteOrder(C.ntoc);
    153   sys::swapByteOrder(C.modtaboff);
    154   sys::swapByteOrder(C.nmodtab);
    155   sys::swapByteOrder(C.extrefsymoff);
    156   sys::swapByteOrder(C.nextrefsyms);
    157   sys::swapByteOrder(C.indirectsymoff);
    158   sys::swapByteOrder(C.nindirectsyms);
    159   sys::swapByteOrder(C.extreloff);
    160   sys::swapByteOrder(C.nextrel);
    161   sys::swapByteOrder(C.locreloff);
    162   sys::swapByteOrder(C.nlocrel);
    163 }
    164 
    165 template<>
    166 void SwapStruct(MachO::linkedit_data_command &C) {
    167   sys::swapByteOrder(C.cmd);
    168   sys::swapByteOrder(C.cmdsize);
    169   sys::swapByteOrder(C.dataoff);
    170   sys::swapByteOrder(C.datasize);
    171 }
    172 
    173 template<>
    174 void SwapStruct(MachO::segment_command &C) {
    175   sys::swapByteOrder(C.cmd);
    176   sys::swapByteOrder(C.cmdsize);
    177   sys::swapByteOrder(C.vmaddr);
    178   sys::swapByteOrder(C.vmsize);
    179   sys::swapByteOrder(C.fileoff);
    180   sys::swapByteOrder(C.filesize);
    181   sys::swapByteOrder(C.maxprot);
    182   sys::swapByteOrder(C.initprot);
    183   sys::swapByteOrder(C.nsects);
    184   sys::swapByteOrder(C.flags);
    185 }
    186 
    187 template<>
    188 void SwapStruct(MachO::segment_command_64 &C) {
    189   sys::swapByteOrder(C.cmd);
    190   sys::swapByteOrder(C.cmdsize);
    191   sys::swapByteOrder(C.vmaddr);
    192   sys::swapByteOrder(C.vmsize);
    193   sys::swapByteOrder(C.fileoff);
    194   sys::swapByteOrder(C.filesize);
    195   sys::swapByteOrder(C.maxprot);
    196   sys::swapByteOrder(C.initprot);
    197   sys::swapByteOrder(C.nsects);
    198   sys::swapByteOrder(C.flags);
    199 }
    200 
    201 template<>
    202 void SwapStruct(uint32_t &C) {
    203   sys::swapByteOrder(C);
    204 }
    205 
    206 template<>
    207 void SwapStruct(MachO::linker_options_command &C) {
    208   sys::swapByteOrder(C.cmd);
    209   sys::swapByteOrder(C.cmdsize);
    210   sys::swapByteOrder(C.count);
    211 }
    212 
    213 template<>
    214 void SwapStruct(MachO::version_min_command&C) {
    215   sys::swapByteOrder(C.cmd);
    216   sys::swapByteOrder(C.cmdsize);
    217   sys::swapByteOrder(C.version);
    218   sys::swapByteOrder(C.reserved);
    219 }
    220 
    221 template<>
    222 void SwapStruct(MachO::dylib_command&C) {
    223   sys::swapByteOrder(C.cmd);
    224   sys::swapByteOrder(C.cmdsize);
    225   sys::swapByteOrder(C.dylib.name);
    226   sys::swapByteOrder(C.dylib.timestamp);
    227   sys::swapByteOrder(C.dylib.current_version);
    228   sys::swapByteOrder(C.dylib.compatibility_version);
    229 }
    230 
    231 template<>
    232 void SwapStruct(MachO::data_in_code_entry &C) {
    233   sys::swapByteOrder(C.offset);
    234   sys::swapByteOrder(C.length);
    235   sys::swapByteOrder(C.kind);
    236 }
    237 
    238 template<typename T>
    239 T getStruct(const MachOObjectFile *O, const char *P) {
    240   T Cmd;
    241   memcpy(&Cmd, P, sizeof(T));
    242   if (O->isLittleEndian() != sys::IsLittleEndianHost)
    243     SwapStruct(Cmd);
    244   return Cmd;
    245 }
    246 
    247 static uint32_t
    248 getSegmentLoadCommandNumSections(const MachOObjectFile *O,
    249                                  const MachOObjectFile::LoadCommandInfo &L) {
    250   if (O->is64Bit()) {
    251     MachO::segment_command_64 S = O->getSegment64LoadCommand(L);
    252     return S.nsects;
    253   }
    254   MachO::segment_command S = O->getSegmentLoadCommand(L);
    255   return S.nsects;
    256 }
    257 
    258 static const char *
    259 getSectionPtr(const MachOObjectFile *O, MachOObjectFile::LoadCommandInfo L,
    260               unsigned Sec) {
    261   uintptr_t CommandAddr = reinterpret_cast<uintptr_t>(L.Ptr);
    262 
    263   bool Is64 = O->is64Bit();
    264   unsigned SegmentLoadSize = Is64 ? sizeof(MachO::segment_command_64) :
    265                                     sizeof(MachO::segment_command);
    266   unsigned SectionSize = Is64 ? sizeof(MachO::section_64) :
    267                                 sizeof(MachO::section);
    268 
    269   uintptr_t SectionAddr = CommandAddr + SegmentLoadSize + Sec * SectionSize;
    270   return reinterpret_cast<const char*>(SectionAddr);
    271 }
    272 
    273 static const char *getPtr(const MachOObjectFile *O, size_t Offset) {
    274   return O->getData().substr(Offset, 1).data();
    275 }
    276 
    277 static nlist_base
    278 getSymbolTableEntryBase(const MachOObjectFile *O, DataRefImpl DRI) {
    279   const char *P = reinterpret_cast<const char *>(DRI.p);
    280   return getStruct<nlist_base>(O, P);
    281 }
    282 
    283 static StringRef parseSegmentOrSectionName(const char *P) {
    284   if (P[15] == 0)
    285     // Null terminated.
    286     return P;
    287   // Not null terminated, so this is a 16 char string.
    288   return StringRef(P, 16);
    289 }
    290 
    291 // Helper to advance a section or symbol iterator multiple increments at a time.
    292 template<class T>
    293 static void advance(T &it, size_t Val) {
    294   while (Val--)
    295     ++it;
    296 }
    297 
    298 static unsigned getCPUType(const MachOObjectFile *O) {
    299   return O->getHeader().cputype;
    300 }
    301 
    302 static void printRelocationTargetName(const MachOObjectFile *O,
    303                                       const MachO::any_relocation_info &RE,
    304                                       raw_string_ostream &fmt) {
    305   bool IsScattered = O->isRelocationScattered(RE);
    306 
    307   // Target of a scattered relocation is an address.  In the interest of
    308   // generating pretty output, scan through the symbol table looking for a
    309   // symbol that aligns with that address.  If we find one, print it.
    310   // Otherwise, we just print the hex address of the target.
    311   if (IsScattered) {
    312     uint32_t Val = O->getPlainRelocationSymbolNum(RE);
    313 
    314     for (const SymbolRef &Symbol : O->symbols()) {
    315       std::error_code ec;
    316       uint64_t Addr;
    317       StringRef Name;
    318 
    319       if ((ec = Symbol.getAddress(Addr)))
    320         report_fatal_error(ec.message());
    321       if (Addr != Val)
    322         continue;
    323       if ((ec = Symbol.getName(Name)))
    324         report_fatal_error(ec.message());
    325       fmt << Name;
    326       return;
    327     }
    328 
    329     // If we couldn't find a symbol that this relocation refers to, try
    330     // to find a section beginning instead.
    331     for (const SectionRef &Section : O->sections()) {
    332       std::error_code ec;
    333       uint64_t Addr;
    334       StringRef Name;
    335 
    336       if ((ec = Section.getAddress(Addr)))
    337         report_fatal_error(ec.message());
    338       if (Addr != Val)
    339         continue;
    340       if ((ec = Section.getName(Name)))
    341         report_fatal_error(ec.message());
    342       fmt << Name;
    343       return;
    344     }
    345 
    346     fmt << format("0x%x", Val);
    347     return;
    348   }
    349 
    350   StringRef S;
    351   bool isExtern = O->getPlainRelocationExternal(RE);
    352   uint64_t Val = O->getPlainRelocationSymbolNum(RE);
    353 
    354   if (isExtern) {
    355     symbol_iterator SI = O->symbol_begin();
    356     advance(SI, Val);
    357     SI->getName(S);
    358   } else {
    359     section_iterator SI = O->section_begin();
    360     // Adjust for the fact that sections are 1-indexed.
    361     advance(SI, Val - 1);
    362     SI->getName(S);
    363   }
    364 
    365   fmt << S;
    366 }
    367 
    368 static uint32_t
    369 getPlainRelocationAddress(const MachO::any_relocation_info &RE) {
    370   return RE.r_word0;
    371 }
    372 
    373 static unsigned
    374 getScatteredRelocationAddress(const MachO::any_relocation_info &RE) {
    375   return RE.r_word0 & 0xffffff;
    376 }
    377 
    378 static bool getPlainRelocationPCRel(const MachOObjectFile *O,
    379                                     const MachO::any_relocation_info &RE) {
    380   if (O->isLittleEndian())
    381     return (RE.r_word1 >> 24) & 1;
    382   return (RE.r_word1 >> 7) & 1;
    383 }
    384 
    385 static bool
    386 getScatteredRelocationPCRel(const MachOObjectFile *O,
    387                             const MachO::any_relocation_info &RE) {
    388   return (RE.r_word0 >> 30) & 1;
    389 }
    390 
    391 static unsigned getPlainRelocationLength(const MachOObjectFile *O,
    392                                          const MachO::any_relocation_info &RE) {
    393   if (O->isLittleEndian())
    394     return (RE.r_word1 >> 25) & 3;
    395   return (RE.r_word1 >> 5) & 3;
    396 }
    397 
    398 static unsigned
    399 getScatteredRelocationLength(const MachO::any_relocation_info &RE) {
    400   return (RE.r_word0 >> 28) & 3;
    401 }
    402 
    403 static unsigned getPlainRelocationType(const MachOObjectFile *O,
    404                                        const MachO::any_relocation_info &RE) {
    405   if (O->isLittleEndian())
    406     return RE.r_word1 >> 28;
    407   return RE.r_word1 & 0xf;
    408 }
    409 
    410 static unsigned
    411 getScatteredRelocationType(const MachO::any_relocation_info &RE) {
    412   return (RE.r_word0 >> 24) & 0xf;
    413 }
    414 
    415 static uint32_t getSectionFlags(const MachOObjectFile *O,
    416                                 DataRefImpl Sec) {
    417   if (O->is64Bit()) {
    418     MachO::section_64 Sect = O->getSection64(Sec);
    419     return Sect.flags;
    420   }
    421   MachO::section Sect = O->getSection(Sec);
    422   return Sect.flags;
    423 }
    424 
    425 MachOObjectFile::MachOObjectFile(std::unique_ptr<MemoryBuffer> Object,
    426                                  bool IsLittleEndian, bool Is64bits,
    427                                  std::error_code &EC)
    428     : ObjectFile(getMachOType(IsLittleEndian, Is64bits), std::move(Object)),
    429       SymtabLoadCmd(nullptr), DysymtabLoadCmd(nullptr),
    430       DataInCodeLoadCmd(nullptr) {
    431   uint32_t LoadCommandCount = this->getHeader().ncmds;
    432   MachO::LoadCommandType SegmentLoadType = is64Bit() ?
    433     MachO::LC_SEGMENT_64 : MachO::LC_SEGMENT;
    434 
    435   MachOObjectFile::LoadCommandInfo Load = getFirstLoadCommandInfo();
    436   for (unsigned I = 0; ; ++I) {
    437     if (Load.C.cmd == MachO::LC_SYMTAB) {
    438       assert(!SymtabLoadCmd && "Multiple symbol tables");
    439       SymtabLoadCmd = Load.Ptr;
    440     } else if (Load.C.cmd == MachO::LC_DYSYMTAB) {
    441       assert(!DysymtabLoadCmd && "Multiple dynamic symbol tables");
    442       DysymtabLoadCmd = Load.Ptr;
    443     } else if (Load.C.cmd == MachO::LC_DATA_IN_CODE) {
    444       assert(!DataInCodeLoadCmd && "Multiple data in code tables");
    445       DataInCodeLoadCmd = Load.Ptr;
    446     } else if (Load.C.cmd == SegmentLoadType) {
    447       uint32_t NumSections = getSegmentLoadCommandNumSections(this, Load);
    448       for (unsigned J = 0; J < NumSections; ++J) {
    449         const char *Sec = getSectionPtr(this, Load, J);
    450         Sections.push_back(Sec);
    451       }
    452     } else if (Load.C.cmd == MachO::LC_LOAD_DYLIB ||
    453                Load.C.cmd == MachO::LC_LOAD_WEAK_DYLIB ||
    454                Load.C.cmd == MachO::LC_LAZY_LOAD_DYLIB ||
    455                Load.C.cmd == MachO::LC_REEXPORT_DYLIB ||
    456                Load.C.cmd == MachO::LC_LOAD_UPWARD_DYLIB) {
    457       Libraries.push_back(Load.Ptr);
    458     }
    459 
    460     if (I == LoadCommandCount - 1)
    461       break;
    462     else
    463       Load = getNextLoadCommandInfo(Load);
    464   }
    465 }
    466 
    467 void MachOObjectFile::moveSymbolNext(DataRefImpl &Symb) const {
    468   unsigned SymbolTableEntrySize = is64Bit() ?
    469     sizeof(MachO::nlist_64) :
    470     sizeof(MachO::nlist);
    471   Symb.p += SymbolTableEntrySize;
    472 }
    473 
    474 std::error_code MachOObjectFile::getSymbolName(DataRefImpl Symb,
    475                                                StringRef &Res) const {
    476   StringRef StringTable = getStringTableData();
    477   nlist_base Entry = getSymbolTableEntryBase(this, Symb);
    478   const char *Start = &StringTable.data()[Entry.n_strx];
    479   Res = StringRef(Start);
    480   return object_error::success;
    481 }
    482 
    483 // getIndirectName() returns the name of the alias'ed symbol who's string table
    484 // index is in the n_value field.
    485 std::error_code MachOObjectFile::getIndirectName(DataRefImpl Symb,
    486                                                  StringRef &Res) const {
    487   StringRef StringTable = getStringTableData();
    488   uint64_t NValue;
    489   if (is64Bit()) {
    490     MachO::nlist_64 Entry = getSymbol64TableEntry(Symb);
    491     NValue = Entry.n_value;
    492     if ((Entry.n_type & MachO::N_TYPE) != MachO::N_INDR)
    493       return object_error::parse_failed;
    494   } else {
    495     MachO::nlist Entry = getSymbolTableEntry(Symb);
    496     NValue = Entry.n_value;
    497     if ((Entry.n_type & MachO::N_TYPE) != MachO::N_INDR)
    498       return object_error::parse_failed;
    499   }
    500   if (NValue >= StringTable.size())
    501     return object_error::parse_failed;
    502   const char *Start = &StringTable.data()[NValue];
    503   Res = StringRef(Start);
    504   return object_error::success;
    505 }
    506 
    507 std::error_code MachOObjectFile::getSymbolAddress(DataRefImpl Symb,
    508                                                   uint64_t &Res) const {
    509   if (is64Bit()) {
    510     MachO::nlist_64 Entry = getSymbol64TableEntry(Symb);
    511     if ((Entry.n_type & MachO::N_TYPE) == MachO::N_UNDF &&
    512         Entry.n_value == 0)
    513       Res = UnknownAddressOrSize;
    514     else
    515       Res = Entry.n_value;
    516   } else {
    517     MachO::nlist Entry = getSymbolTableEntry(Symb);
    518     if ((Entry.n_type & MachO::N_TYPE) == MachO::N_UNDF &&
    519         Entry.n_value == 0)
    520       Res = UnknownAddressOrSize;
    521     else
    522       Res = Entry.n_value;
    523   }
    524   return object_error::success;
    525 }
    526 
    527 std::error_code MachOObjectFile::getSymbolAlignment(DataRefImpl DRI,
    528                                                     uint32_t &Result) const {
    529   uint32_t flags = getSymbolFlags(DRI);
    530   if (flags & SymbolRef::SF_Common) {
    531     nlist_base Entry = getSymbolTableEntryBase(this, DRI);
    532     Result = 1 << MachO::GET_COMM_ALIGN(Entry.n_desc);
    533   } else {
    534     Result = 0;
    535   }
    536   return object_error::success;
    537 }
    538 
    539 std::error_code MachOObjectFile::getSymbolSize(DataRefImpl DRI,
    540                                                uint64_t &Result) const {
    541   uint64_t BeginOffset;
    542   uint64_t EndOffset = 0;
    543   uint8_t SectionIndex;
    544 
    545   nlist_base Entry = getSymbolTableEntryBase(this, DRI);
    546   uint64_t Value;
    547   getSymbolAddress(DRI, Value);
    548   if (Value == UnknownAddressOrSize) {
    549     Result = UnknownAddressOrSize;
    550     return object_error::success;
    551   }
    552 
    553   BeginOffset = Value;
    554 
    555   SectionIndex = Entry.n_sect;
    556   if (!SectionIndex) {
    557     uint32_t flags = getSymbolFlags(DRI);
    558     if (flags & SymbolRef::SF_Common)
    559       Result = Value;
    560     else
    561       Result = UnknownAddressOrSize;
    562     return object_error::success;
    563   }
    564   // Unfortunately symbols are unsorted so we need to touch all
    565   // symbols from load command
    566   for (const SymbolRef &Symbol : symbols()) {
    567     DataRefImpl DRI = Symbol.getRawDataRefImpl();
    568     Entry = getSymbolTableEntryBase(this, DRI);
    569     getSymbolAddress(DRI, Value);
    570     if (Value == UnknownAddressOrSize)
    571       continue;
    572     if (Entry.n_sect == SectionIndex && Value > BeginOffset)
    573       if (!EndOffset || Value < EndOffset)
    574         EndOffset = Value;
    575   }
    576   if (!EndOffset) {
    577     uint64_t Size;
    578     DataRefImpl Sec;
    579     Sec.d.a = SectionIndex-1;
    580     getSectionSize(Sec, Size);
    581     getSectionAddress(Sec, EndOffset);
    582     EndOffset += Size;
    583   }
    584   Result = EndOffset - BeginOffset;
    585   return object_error::success;
    586 }
    587 
    588 std::error_code MachOObjectFile::getSymbolType(DataRefImpl Symb,
    589                                                SymbolRef::Type &Res) const {
    590   nlist_base Entry = getSymbolTableEntryBase(this, Symb);
    591   uint8_t n_type = Entry.n_type;
    592 
    593   Res = SymbolRef::ST_Other;
    594 
    595   // If this is a STAB debugging symbol, we can do nothing more.
    596   if (n_type & MachO::N_STAB) {
    597     Res = SymbolRef::ST_Debug;
    598     return object_error::success;
    599   }
    600 
    601   switch (n_type & MachO::N_TYPE) {
    602     case MachO::N_UNDF :
    603       Res = SymbolRef::ST_Unknown;
    604       break;
    605     case MachO::N_SECT :
    606       Res = SymbolRef::ST_Function;
    607       break;
    608   }
    609   return object_error::success;
    610 }
    611 
    612 uint32_t MachOObjectFile::getSymbolFlags(DataRefImpl DRI) const {
    613   nlist_base Entry = getSymbolTableEntryBase(this, DRI);
    614 
    615   uint8_t MachOType = Entry.n_type;
    616   uint16_t MachOFlags = Entry.n_desc;
    617 
    618   uint32_t Result = SymbolRef::SF_None;
    619 
    620   if ((MachOType & MachO::N_TYPE) == MachO::N_UNDF)
    621     Result |= SymbolRef::SF_Undefined;
    622 
    623   if ((MachOType & MachO::N_TYPE) == MachO::N_INDR)
    624     Result |= SymbolRef::SF_Indirect;
    625 
    626   if (MachOType & MachO::N_STAB)
    627     Result |= SymbolRef::SF_FormatSpecific;
    628 
    629   if (MachOType & MachO::N_EXT) {
    630     Result |= SymbolRef::SF_Global;
    631     if ((MachOType & MachO::N_TYPE) == MachO::N_UNDF) {
    632       uint64_t Value;
    633       getSymbolAddress(DRI, Value);
    634       if (Value && Value != UnknownAddressOrSize)
    635         Result |= SymbolRef::SF_Common;
    636     }
    637   }
    638 
    639   if (MachOFlags & (MachO::N_WEAK_REF | MachO::N_WEAK_DEF))
    640     Result |= SymbolRef::SF_Weak;
    641 
    642   if ((MachOType & MachO::N_TYPE) == MachO::N_ABS)
    643     Result |= SymbolRef::SF_Absolute;
    644 
    645   return Result;
    646 }
    647 
    648 std::error_code MachOObjectFile::getSymbolSection(DataRefImpl Symb,
    649                                                   section_iterator &Res) const {
    650   nlist_base Entry = getSymbolTableEntryBase(this, Symb);
    651   uint8_t index = Entry.n_sect;
    652 
    653   if (index == 0) {
    654     Res = section_end();
    655   } else {
    656     DataRefImpl DRI;
    657     DRI.d.a = index - 1;
    658     Res = section_iterator(SectionRef(DRI, this));
    659   }
    660 
    661   return object_error::success;
    662 }
    663 
    664 void MachOObjectFile::moveSectionNext(DataRefImpl &Sec) const {
    665   Sec.d.a++;
    666 }
    667 
    668 std::error_code MachOObjectFile::getSectionName(DataRefImpl Sec,
    669                                                 StringRef &Result) const {
    670   ArrayRef<char> Raw = getSectionRawName(Sec);
    671   Result = parseSegmentOrSectionName(Raw.data());
    672   return object_error::success;
    673 }
    674 
    675 std::error_code MachOObjectFile::getSectionAddress(DataRefImpl Sec,
    676                                                    uint64_t &Res) const {
    677   if (is64Bit()) {
    678     MachO::section_64 Sect = getSection64(Sec);
    679     Res = Sect.addr;
    680   } else {
    681     MachO::section Sect = getSection(Sec);
    682     Res = Sect.addr;
    683   }
    684   return object_error::success;
    685 }
    686 
    687 std::error_code MachOObjectFile::getSectionSize(DataRefImpl Sec,
    688                                                 uint64_t &Res) const {
    689   if (is64Bit()) {
    690     MachO::section_64 Sect = getSection64(Sec);
    691     Res = Sect.size;
    692   } else {
    693     MachO::section Sect = getSection(Sec);
    694     Res = Sect.size;
    695   }
    696 
    697   return object_error::success;
    698 }
    699 
    700 std::error_code MachOObjectFile::getSectionContents(DataRefImpl Sec,
    701                                                     StringRef &Res) const {
    702   uint32_t Offset;
    703   uint64_t Size;
    704 
    705   if (is64Bit()) {
    706     MachO::section_64 Sect = getSection64(Sec);
    707     Offset = Sect.offset;
    708     Size = Sect.size;
    709   } else {
    710     MachO::section Sect = getSection(Sec);
    711     Offset = Sect.offset;
    712     Size = Sect.size;
    713   }
    714 
    715   Res = this->getData().substr(Offset, Size);
    716   return object_error::success;
    717 }
    718 
    719 std::error_code MachOObjectFile::getSectionAlignment(DataRefImpl Sec,
    720                                                      uint64_t &Res) const {
    721   uint32_t Align;
    722   if (is64Bit()) {
    723     MachO::section_64 Sect = getSection64(Sec);
    724     Align = Sect.align;
    725   } else {
    726     MachO::section Sect = getSection(Sec);
    727     Align = Sect.align;
    728   }
    729 
    730   Res = uint64_t(1) << Align;
    731   return object_error::success;
    732 }
    733 
    734 std::error_code MachOObjectFile::isSectionText(DataRefImpl Sec,
    735                                                bool &Res) const {
    736   uint32_t Flags = getSectionFlags(this, Sec);
    737   Res = Flags & MachO::S_ATTR_PURE_INSTRUCTIONS;
    738   return object_error::success;
    739 }
    740 
    741 std::error_code MachOObjectFile::isSectionData(DataRefImpl Sec,
    742                                                bool &Result) const {
    743   uint32_t Flags = getSectionFlags(this, Sec);
    744   unsigned SectionType = Flags & MachO::SECTION_TYPE;
    745   Result = !(Flags & MachO::S_ATTR_PURE_INSTRUCTIONS) &&
    746            !(SectionType == MachO::S_ZEROFILL ||
    747              SectionType == MachO::S_GB_ZEROFILL);
    748   return object_error::success;
    749 }
    750 
    751 std::error_code MachOObjectFile::isSectionBSS(DataRefImpl Sec,
    752                                               bool &Result) const {
    753   uint32_t Flags = getSectionFlags(this, Sec);
    754   unsigned SectionType = Flags & MachO::SECTION_TYPE;
    755   Result = !(Flags & MachO::S_ATTR_PURE_INSTRUCTIONS) &&
    756            (SectionType == MachO::S_ZEROFILL ||
    757             SectionType == MachO::S_GB_ZEROFILL);
    758   return object_error::success;
    759 }
    760 
    761 std::error_code
    762 MachOObjectFile::isSectionRequiredForExecution(DataRefImpl Sec,
    763                                                bool &Result) const {
    764   // FIXME: Unimplemented.
    765   Result = true;
    766   return object_error::success;
    767 }
    768 
    769 std::error_code MachOObjectFile::isSectionVirtual(DataRefImpl Sec,
    770                                                   bool &Result) const {
    771   // FIXME: Unimplemented.
    772   Result = false;
    773   return object_error::success;
    774 }
    775 
    776 std::error_code MachOObjectFile::isSectionZeroInit(DataRefImpl Sec,
    777                                                    bool &Res) const {
    778   uint32_t Flags = getSectionFlags(this, Sec);
    779   unsigned SectionType = Flags & MachO::SECTION_TYPE;
    780   Res = SectionType == MachO::S_ZEROFILL ||
    781     SectionType == MachO::S_GB_ZEROFILL;
    782   return object_error::success;
    783 }
    784 
    785 std::error_code MachOObjectFile::isSectionReadOnlyData(DataRefImpl Sec,
    786                                                        bool &Result) const {
    787   // Consider using the code from isSectionText to look for __const sections.
    788   // Alternately, emit S_ATTR_PURE_INSTRUCTIONS and/or S_ATTR_SOME_INSTRUCTIONS
    789   // to use section attributes to distinguish code from data.
    790 
    791   // FIXME: Unimplemented.
    792   Result = false;
    793   return object_error::success;
    794 }
    795 
    796 std::error_code MachOObjectFile::sectionContainsSymbol(DataRefImpl Sec,
    797                                                        DataRefImpl Symb,
    798                                                        bool &Result) const {
    799   SymbolRef::Type ST;
    800   this->getSymbolType(Symb, ST);
    801   if (ST == SymbolRef::ST_Unknown) {
    802     Result = false;
    803     return object_error::success;
    804   }
    805 
    806   uint64_t SectBegin, SectEnd;
    807   getSectionAddress(Sec, SectBegin);
    808   getSectionSize(Sec, SectEnd);
    809   SectEnd += SectBegin;
    810 
    811   uint64_t SymAddr;
    812   getSymbolAddress(Symb, SymAddr);
    813   Result = (SymAddr >= SectBegin) && (SymAddr < SectEnd);
    814 
    815   return object_error::success;
    816 }
    817 
    818 relocation_iterator MachOObjectFile::section_rel_begin(DataRefImpl Sec) const {
    819   DataRefImpl Ret;
    820   Ret.d.a = Sec.d.a;
    821   Ret.d.b = 0;
    822   return relocation_iterator(RelocationRef(Ret, this));
    823 }
    824 
    825 relocation_iterator
    826 MachOObjectFile::section_rel_end(DataRefImpl Sec) const {
    827   uint32_t Num;
    828   if (is64Bit()) {
    829     MachO::section_64 Sect = getSection64(Sec);
    830     Num = Sect.nreloc;
    831   } else {
    832     MachO::section Sect = getSection(Sec);
    833     Num = Sect.nreloc;
    834   }
    835 
    836   DataRefImpl Ret;
    837   Ret.d.a = Sec.d.a;
    838   Ret.d.b = Num;
    839   return relocation_iterator(RelocationRef(Ret, this));
    840 }
    841 
    842 void MachOObjectFile::moveRelocationNext(DataRefImpl &Rel) const {
    843   ++Rel.d.b;
    844 }
    845 
    846 std::error_code MachOObjectFile::getRelocationAddress(DataRefImpl Rel,
    847                                                       uint64_t &Res) const {
    848   uint64_t Offset;
    849   getRelocationOffset(Rel, Offset);
    850 
    851   DataRefImpl Sec;
    852   Sec.d.a = Rel.d.a;
    853   uint64_t SecAddress;
    854   getSectionAddress(Sec, SecAddress);
    855   Res = SecAddress + Offset;
    856   return object_error::success;
    857 }
    858 
    859 std::error_code MachOObjectFile::getRelocationOffset(DataRefImpl Rel,
    860                                                      uint64_t &Res) const {
    861   assert(getHeader().filetype == MachO::MH_OBJECT &&
    862          "Only implemented for MH_OBJECT");
    863   MachO::any_relocation_info RE = getRelocation(Rel);
    864   Res = getAnyRelocationAddress(RE);
    865   return object_error::success;
    866 }
    867 
    868 symbol_iterator
    869 MachOObjectFile::getRelocationSymbol(DataRefImpl Rel) const {
    870   MachO::any_relocation_info RE = getRelocation(Rel);
    871   if (isRelocationScattered(RE))
    872     return symbol_end();
    873 
    874   uint32_t SymbolIdx = getPlainRelocationSymbolNum(RE);
    875   bool isExtern = getPlainRelocationExternal(RE);
    876   if (!isExtern)
    877     return symbol_end();
    878 
    879   MachO::symtab_command S = getSymtabLoadCommand();
    880   unsigned SymbolTableEntrySize = is64Bit() ?
    881     sizeof(MachO::nlist_64) :
    882     sizeof(MachO::nlist);
    883   uint64_t Offset = S.symoff + SymbolIdx * SymbolTableEntrySize;
    884   DataRefImpl Sym;
    885   Sym.p = reinterpret_cast<uintptr_t>(getPtr(this, Offset));
    886   return symbol_iterator(SymbolRef(Sym, this));
    887 }
    888 
    889 std::error_code MachOObjectFile::getRelocationType(DataRefImpl Rel,
    890                                                    uint64_t &Res) const {
    891   MachO::any_relocation_info RE = getRelocation(Rel);
    892   Res = getAnyRelocationType(RE);
    893   return object_error::success;
    894 }
    895 
    896 std::error_code
    897 MachOObjectFile::getRelocationTypeName(DataRefImpl Rel,
    898                                        SmallVectorImpl<char> &Result) const {
    899   StringRef res;
    900   uint64_t RType;
    901   getRelocationType(Rel, RType);
    902 
    903   unsigned Arch = this->getArch();
    904 
    905   switch (Arch) {
    906     case Triple::x86: {
    907       static const char *const Table[] =  {
    908         "GENERIC_RELOC_VANILLA",
    909         "GENERIC_RELOC_PAIR",
    910         "GENERIC_RELOC_SECTDIFF",
    911         "GENERIC_RELOC_PB_LA_PTR",
    912         "GENERIC_RELOC_LOCAL_SECTDIFF",
    913         "GENERIC_RELOC_TLV" };
    914 
    915       if (RType > 5)
    916         res = "Unknown";
    917       else
    918         res = Table[RType];
    919       break;
    920     }
    921     case Triple::x86_64: {
    922       static const char *const Table[] =  {
    923         "X86_64_RELOC_UNSIGNED",
    924         "X86_64_RELOC_SIGNED",
    925         "X86_64_RELOC_BRANCH",
    926         "X86_64_RELOC_GOT_LOAD",
    927         "X86_64_RELOC_GOT",
    928         "X86_64_RELOC_SUBTRACTOR",
    929         "X86_64_RELOC_SIGNED_1",
    930         "X86_64_RELOC_SIGNED_2",
    931         "X86_64_RELOC_SIGNED_4",
    932         "X86_64_RELOC_TLV" };
    933 
    934       if (RType > 9)
    935         res = "Unknown";
    936       else
    937         res = Table[RType];
    938       break;
    939     }
    940     case Triple::arm: {
    941       static const char *const Table[] =  {
    942         "ARM_RELOC_VANILLA",
    943         "ARM_RELOC_PAIR",
    944         "ARM_RELOC_SECTDIFF",
    945         "ARM_RELOC_LOCAL_SECTDIFF",
    946         "ARM_RELOC_PB_LA_PTR",
    947         "ARM_RELOC_BR24",
    948         "ARM_THUMB_RELOC_BR22",
    949         "ARM_THUMB_32BIT_BRANCH",
    950         "ARM_RELOC_HALF",
    951         "ARM_RELOC_HALF_SECTDIFF" };
    952 
    953       if (RType > 9)
    954         res = "Unknown";
    955       else
    956         res = Table[RType];
    957       break;
    958     }
    959     case Triple::arm64:
    960     case Triple::aarch64: {
    961       static const char *const Table[] = {
    962         "ARM64_RELOC_UNSIGNED",           "ARM64_RELOC_SUBTRACTOR",
    963         "ARM64_RELOC_BRANCH26",           "ARM64_RELOC_PAGE21",
    964         "ARM64_RELOC_PAGEOFF12",          "ARM64_RELOC_GOT_LOAD_PAGE21",
    965         "ARM64_RELOC_GOT_LOAD_PAGEOFF12", "ARM64_RELOC_POINTER_TO_GOT",
    966         "ARM64_RELOC_TLVP_LOAD_PAGE21",   "ARM64_RELOC_TLVP_LOAD_PAGEOFF12",
    967         "ARM64_RELOC_ADDEND"
    968       };
    969 
    970       if (RType >= array_lengthof(Table))
    971         res = "Unknown";
    972       else
    973         res = Table[RType];
    974       break;
    975     }
    976     case Triple::ppc: {
    977       static const char *const Table[] =  {
    978         "PPC_RELOC_VANILLA",
    979         "PPC_RELOC_PAIR",
    980         "PPC_RELOC_BR14",
    981         "PPC_RELOC_BR24",
    982         "PPC_RELOC_HI16",
    983         "PPC_RELOC_LO16",
    984         "PPC_RELOC_HA16",
    985         "PPC_RELOC_LO14",
    986         "PPC_RELOC_SECTDIFF",
    987         "PPC_RELOC_PB_LA_PTR",
    988         "PPC_RELOC_HI16_SECTDIFF",
    989         "PPC_RELOC_LO16_SECTDIFF",
    990         "PPC_RELOC_HA16_SECTDIFF",
    991         "PPC_RELOC_JBSR",
    992         "PPC_RELOC_LO14_SECTDIFF",
    993         "PPC_RELOC_LOCAL_SECTDIFF" };
    994 
    995       if (RType > 15)
    996         res = "Unknown";
    997       else
    998         res = Table[RType];
    999       break;
   1000     }
   1001     case Triple::UnknownArch:
   1002       res = "Unknown";
   1003       break;
   1004   }
   1005   Result.append(res.begin(), res.end());
   1006   return object_error::success;
   1007 }
   1008 
   1009 std::error_code
   1010 MachOObjectFile::getRelocationValueString(DataRefImpl Rel,
   1011                                           SmallVectorImpl<char> &Result) const {
   1012   MachO::any_relocation_info RE = getRelocation(Rel);
   1013 
   1014   unsigned Arch = this->getArch();
   1015 
   1016   std::string fmtbuf;
   1017   raw_string_ostream fmt(fmtbuf);
   1018   unsigned Type = this->getAnyRelocationType(RE);
   1019   bool IsPCRel = this->getAnyRelocationPCRel(RE);
   1020 
   1021   // Determine any addends that should be displayed with the relocation.
   1022   // These require decoding the relocation type, which is triple-specific.
   1023 
   1024   // X86_64 has entirely custom relocation types.
   1025   if (Arch == Triple::x86_64) {
   1026     bool isPCRel = getAnyRelocationPCRel(RE);
   1027 
   1028     switch (Type) {
   1029       case MachO::X86_64_RELOC_GOT_LOAD:
   1030       case MachO::X86_64_RELOC_GOT: {
   1031         printRelocationTargetName(this, RE, fmt);
   1032         fmt << "@GOT";
   1033         if (isPCRel) fmt << "PCREL";
   1034         break;
   1035       }
   1036       case MachO::X86_64_RELOC_SUBTRACTOR: {
   1037         DataRefImpl RelNext = Rel;
   1038         moveRelocationNext(RelNext);
   1039         MachO::any_relocation_info RENext = getRelocation(RelNext);
   1040 
   1041         // X86_64_RELOC_SUBTRACTOR must be followed by a relocation of type
   1042         // X86_64_RELOC_UNSIGNED.
   1043         // NOTE: Scattered relocations don't exist on x86_64.
   1044         unsigned RType = getAnyRelocationType(RENext);
   1045         if (RType != MachO::X86_64_RELOC_UNSIGNED)
   1046           report_fatal_error("Expected X86_64_RELOC_UNSIGNED after "
   1047                              "X86_64_RELOC_SUBTRACTOR.");
   1048 
   1049         // The X86_64_RELOC_UNSIGNED contains the minuend symbol;
   1050         // X86_64_RELOC_SUBTRACTOR contains the subtrahend.
   1051         printRelocationTargetName(this, RENext, fmt);
   1052         fmt << "-";
   1053         printRelocationTargetName(this, RE, fmt);
   1054         break;
   1055       }
   1056       case MachO::X86_64_RELOC_TLV:
   1057         printRelocationTargetName(this, RE, fmt);
   1058         fmt << "@TLV";
   1059         if (isPCRel) fmt << "P";
   1060         break;
   1061       case MachO::X86_64_RELOC_SIGNED_1:
   1062         printRelocationTargetName(this, RE, fmt);
   1063         fmt << "-1";
   1064         break;
   1065       case MachO::X86_64_RELOC_SIGNED_2:
   1066         printRelocationTargetName(this, RE, fmt);
   1067         fmt << "-2";
   1068         break;
   1069       case MachO::X86_64_RELOC_SIGNED_4:
   1070         printRelocationTargetName(this, RE, fmt);
   1071         fmt << "-4";
   1072         break;
   1073       default:
   1074         printRelocationTargetName(this, RE, fmt);
   1075         break;
   1076     }
   1077   // X86 and ARM share some relocation types in common.
   1078   } else if (Arch == Triple::x86 || Arch == Triple::arm ||
   1079              Arch == Triple::ppc) {
   1080     // Generic relocation types...
   1081     switch (Type) {
   1082       case MachO::GENERIC_RELOC_PAIR: // prints no info
   1083         return object_error::success;
   1084       case MachO::GENERIC_RELOC_SECTDIFF: {
   1085         DataRefImpl RelNext = Rel;
   1086         moveRelocationNext(RelNext);
   1087         MachO::any_relocation_info RENext = getRelocation(RelNext);
   1088 
   1089         // X86 sect diff's must be followed by a relocation of type
   1090         // GENERIC_RELOC_PAIR.
   1091         unsigned RType = getAnyRelocationType(RENext);
   1092 
   1093         if (RType != MachO::GENERIC_RELOC_PAIR)
   1094           report_fatal_error("Expected GENERIC_RELOC_PAIR after "
   1095                              "GENERIC_RELOC_SECTDIFF.");
   1096 
   1097         printRelocationTargetName(this, RE, fmt);
   1098         fmt << "-";
   1099         printRelocationTargetName(this, RENext, fmt);
   1100         break;
   1101       }
   1102     }
   1103 
   1104     if (Arch == Triple::x86 || Arch == Triple::ppc) {
   1105       switch (Type) {
   1106         case MachO::GENERIC_RELOC_LOCAL_SECTDIFF: {
   1107           DataRefImpl RelNext = Rel;
   1108           moveRelocationNext(RelNext);
   1109           MachO::any_relocation_info RENext = getRelocation(RelNext);
   1110 
   1111           // X86 sect diff's must be followed by a relocation of type
   1112           // GENERIC_RELOC_PAIR.
   1113           unsigned RType = getAnyRelocationType(RENext);
   1114           if (RType != MachO::GENERIC_RELOC_PAIR)
   1115             report_fatal_error("Expected GENERIC_RELOC_PAIR after "
   1116                                "GENERIC_RELOC_LOCAL_SECTDIFF.");
   1117 
   1118           printRelocationTargetName(this, RE, fmt);
   1119           fmt << "-";
   1120           printRelocationTargetName(this, RENext, fmt);
   1121           break;
   1122         }
   1123         case MachO::GENERIC_RELOC_TLV: {
   1124           printRelocationTargetName(this, RE, fmt);
   1125           fmt << "@TLV";
   1126           if (IsPCRel) fmt << "P";
   1127           break;
   1128         }
   1129         default:
   1130           printRelocationTargetName(this, RE, fmt);
   1131       }
   1132     } else { // ARM-specific relocations
   1133       switch (Type) {
   1134         case MachO::ARM_RELOC_HALF:
   1135         case MachO::ARM_RELOC_HALF_SECTDIFF: {
   1136           // Half relocations steal a bit from the length field to encode
   1137           // whether this is an upper16 or a lower16 relocation.
   1138           bool isUpper = getAnyRelocationLength(RE) >> 1;
   1139 
   1140           if (isUpper)
   1141             fmt << ":upper16:(";
   1142           else
   1143             fmt << ":lower16:(";
   1144           printRelocationTargetName(this, RE, fmt);
   1145 
   1146           DataRefImpl RelNext = Rel;
   1147           moveRelocationNext(RelNext);
   1148           MachO::any_relocation_info RENext = getRelocation(RelNext);
   1149 
   1150           // ARM half relocs must be followed by a relocation of type
   1151           // ARM_RELOC_PAIR.
   1152           unsigned RType = getAnyRelocationType(RENext);
   1153           if (RType != MachO::ARM_RELOC_PAIR)
   1154             report_fatal_error("Expected ARM_RELOC_PAIR after "
   1155                                "ARM_RELOC_HALF");
   1156 
   1157           // NOTE: The half of the target virtual address is stashed in the
   1158           // address field of the secondary relocation, but we can't reverse
   1159           // engineer the constant offset from it without decoding the movw/movt
   1160           // instruction to find the other half in its immediate field.
   1161 
   1162           // ARM_RELOC_HALF_SECTDIFF encodes the second section in the
   1163           // symbol/section pointer of the follow-on relocation.
   1164           if (Type == MachO::ARM_RELOC_HALF_SECTDIFF) {
   1165             fmt << "-";
   1166             printRelocationTargetName(this, RENext, fmt);
   1167           }
   1168 
   1169           fmt << ")";
   1170           break;
   1171         }
   1172         default: {
   1173           printRelocationTargetName(this, RE, fmt);
   1174         }
   1175       }
   1176     }
   1177   } else
   1178     printRelocationTargetName(this, RE, fmt);
   1179 
   1180   fmt.flush();
   1181   Result.append(fmtbuf.begin(), fmtbuf.end());
   1182   return object_error::success;
   1183 }
   1184 
   1185 std::error_code MachOObjectFile::getRelocationHidden(DataRefImpl Rel,
   1186                                                      bool &Result) const {
   1187   unsigned Arch = getArch();
   1188   uint64_t Type;
   1189   getRelocationType(Rel, Type);
   1190 
   1191   Result = false;
   1192 
   1193   // On arches that use the generic relocations, GENERIC_RELOC_PAIR
   1194   // is always hidden.
   1195   if (Arch == Triple::x86 || Arch == Triple::arm || Arch == Triple::ppc) {
   1196     if (Type == MachO::GENERIC_RELOC_PAIR) Result = true;
   1197   } else if (Arch == Triple::x86_64) {
   1198     // On x86_64, X86_64_RELOC_UNSIGNED is hidden only when it follows
   1199     // an X86_64_RELOC_SUBTRACTOR.
   1200     if (Type == MachO::X86_64_RELOC_UNSIGNED && Rel.d.a > 0) {
   1201       DataRefImpl RelPrev = Rel;
   1202       RelPrev.d.a--;
   1203       uint64_t PrevType;
   1204       getRelocationType(RelPrev, PrevType);
   1205       if (PrevType == MachO::X86_64_RELOC_SUBTRACTOR)
   1206         Result = true;
   1207     }
   1208   }
   1209 
   1210   return object_error::success;
   1211 }
   1212 
   1213 std::error_code MachOObjectFile::getLibraryNext(DataRefImpl LibData,
   1214                                                 LibraryRef &Res) const {
   1215   report_fatal_error("Needed libraries unimplemented in MachOObjectFile");
   1216 }
   1217 
   1218 std::error_code MachOObjectFile::getLibraryPath(DataRefImpl LibData,
   1219                                                 StringRef &Res) const {
   1220   report_fatal_error("Needed libraries unimplemented in MachOObjectFile");
   1221 }
   1222 
   1223 //
   1224 // guessLibraryShortName() is passed a name of a dynamic library and returns a
   1225 // guess on what the short name is.  Then name is returned as a substring of the
   1226 // StringRef Name passed in.  The name of the dynamic library is recognized as
   1227 // a framework if it has one of the two following forms:
   1228 //      Foo.framework/Versions/A/Foo
   1229 //      Foo.framework/Foo
   1230 // Where A and Foo can be any string.  And may contain a trailing suffix
   1231 // starting with an underbar.  If the Name is recognized as a framework then
   1232 // isFramework is set to true else it is set to false.  If the Name has a
   1233 // suffix then Suffix is set to the substring in Name that contains the suffix
   1234 // else it is set to a NULL StringRef.
   1235 //
   1236 // The Name of the dynamic library is recognized as a library name if it has
   1237 // one of the two following forms:
   1238 //      libFoo.A.dylib
   1239 //      libFoo.dylib
   1240 // The library may have a suffix trailing the name Foo of the form:
   1241 //      libFoo_profile.A.dylib
   1242 //      libFoo_profile.dylib
   1243 //
   1244 // The Name of the dynamic library is also recognized as a library name if it
   1245 // has the following form:
   1246 //      Foo.qtx
   1247 //
   1248 // If the Name of the dynamic library is none of the forms above then a NULL
   1249 // StringRef is returned.
   1250 //
   1251 StringRef MachOObjectFile::guessLibraryShortName(StringRef Name,
   1252                                                  bool &isFramework,
   1253                                                  StringRef &Suffix) {
   1254   StringRef Foo, F, DotFramework, V, Dylib, Lib, Dot, Qtx;
   1255   size_t a, b, c, d, Idx;
   1256 
   1257   isFramework = false;
   1258   Suffix = StringRef();
   1259 
   1260   // Pull off the last component and make Foo point to it
   1261   a = Name.rfind('/');
   1262   if (a == Name.npos || a == 0)
   1263     goto guess_library;
   1264   Foo = Name.slice(a+1, Name.npos);
   1265 
   1266   // Look for a suffix starting with a '_'
   1267   Idx = Foo.rfind('_');
   1268   if (Idx != Foo.npos && Foo.size() >= 2) {
   1269     Suffix = Foo.slice(Idx, Foo.npos);
   1270     Foo = Foo.slice(0, Idx);
   1271   }
   1272 
   1273   // First look for the form Foo.framework/Foo
   1274   b = Name.rfind('/', a);
   1275   if (b == Name.npos)
   1276     Idx = 0;
   1277   else
   1278     Idx = b+1;
   1279   F = Name.slice(Idx, Idx + Foo.size());
   1280   DotFramework = Name.slice(Idx + Foo.size(),
   1281                             Idx + Foo.size() + sizeof(".framework/")-1);
   1282   if (F == Foo && DotFramework == ".framework/") {
   1283     isFramework = true;
   1284     return Foo;
   1285   }
   1286 
   1287   // Next look for the form Foo.framework/Versions/A/Foo
   1288   if (b == Name.npos)
   1289     goto guess_library;
   1290   c =  Name.rfind('/', b);
   1291   if (c == Name.npos || c == 0)
   1292     goto guess_library;
   1293   V = Name.slice(c+1, Name.npos);
   1294   if (!V.startswith("Versions/"))
   1295     goto guess_library;
   1296   d =  Name.rfind('/', c);
   1297   if (d == Name.npos)
   1298     Idx = 0;
   1299   else
   1300     Idx = d+1;
   1301   F = Name.slice(Idx, Idx + Foo.size());
   1302   DotFramework = Name.slice(Idx + Foo.size(),
   1303                             Idx + Foo.size() + sizeof(".framework/")-1);
   1304   if (F == Foo && DotFramework == ".framework/") {
   1305     isFramework = true;
   1306     return Foo;
   1307   }
   1308 
   1309 guess_library:
   1310   // pull off the suffix after the "." and make a point to it
   1311   a = Name.rfind('.');
   1312   if (a == Name.npos || a == 0)
   1313     return StringRef();
   1314   Dylib = Name.slice(a, Name.npos);
   1315   if (Dylib != ".dylib")
   1316     goto guess_qtx;
   1317 
   1318   // First pull off the version letter for the form Foo.A.dylib if any.
   1319   if (a >= 3) {
   1320     Dot = Name.slice(a-2, a-1);
   1321     if (Dot == ".")
   1322       a = a - 2;
   1323   }
   1324 
   1325   b = Name.rfind('/', a);
   1326   if (b == Name.npos)
   1327     b = 0;
   1328   else
   1329     b = b+1;
   1330   // ignore any suffix after an underbar like Foo_profile.A.dylib
   1331   Idx = Name.find('_', b);
   1332   if (Idx != Name.npos && Idx != b) {
   1333     Lib = Name.slice(b, Idx);
   1334     Suffix = Name.slice(Idx, a);
   1335   }
   1336   else
   1337     Lib = Name.slice(b, a);
   1338   // There are incorrect library names of the form:
   1339   // libATS.A_profile.dylib so check for these.
   1340   if (Lib.size() >= 3) {
   1341     Dot = Lib.slice(Lib.size()-2, Lib.size()-1);
   1342     if (Dot == ".")
   1343       Lib = Lib.slice(0, Lib.size()-2);
   1344   }
   1345   return Lib;
   1346 
   1347 guess_qtx:
   1348   Qtx = Name.slice(a, Name.npos);
   1349   if (Qtx != ".qtx")
   1350     return StringRef();
   1351   b = Name.rfind('/', a);
   1352   if (b == Name.npos)
   1353     Lib = Name.slice(0, a);
   1354   else
   1355     Lib = Name.slice(b+1, a);
   1356   // There are library names of the form: QT.A.qtx so check for these.
   1357   if (Lib.size() >= 3) {
   1358     Dot = Lib.slice(Lib.size()-2, Lib.size()-1);
   1359     if (Dot == ".")
   1360       Lib = Lib.slice(0, Lib.size()-2);
   1361   }
   1362   return Lib;
   1363 }
   1364 
   1365 // getLibraryShortNameByIndex() is used to get the short name of the library
   1366 // for an undefined symbol in a linked Mach-O binary that was linked with the
   1367 // normal two-level namespace default (that is MH_TWOLEVEL in the header).
   1368 // It is passed the index (0 - based) of the library as translated from
   1369 // GET_LIBRARY_ORDINAL (1 - based).
   1370 std::error_code MachOObjectFile::getLibraryShortNameByIndex(unsigned Index,
   1371                                                             StringRef &Res) {
   1372   if (Index >= Libraries.size())
   1373     return object_error::parse_failed;
   1374 
   1375   MachO::dylib_command D =
   1376     getStruct<MachO::dylib_command>(this, Libraries[Index]);
   1377   if (D.dylib.name >= D.cmdsize)
   1378     return object_error::parse_failed;
   1379 
   1380   // If the cache of LibrariesShortNames is not built up do that first for
   1381   // all the Libraries.
   1382   if (LibrariesShortNames.size() == 0) {
   1383     for (unsigned i = 0; i < Libraries.size(); i++) {
   1384       MachO::dylib_command D =
   1385         getStruct<MachO::dylib_command>(this, Libraries[i]);
   1386       if (D.dylib.name >= D.cmdsize) {
   1387         LibrariesShortNames.push_back(StringRef());
   1388         continue;
   1389       }
   1390       const char *P = (const char *)(Libraries[i]) + D.dylib.name;
   1391       StringRef Name = StringRef(P);
   1392       StringRef Suffix;
   1393       bool isFramework;
   1394       StringRef shortName = guessLibraryShortName(Name, isFramework, Suffix);
   1395       if (shortName == StringRef())
   1396         LibrariesShortNames.push_back(Name);
   1397       else
   1398         LibrariesShortNames.push_back(shortName);
   1399     }
   1400   }
   1401 
   1402   Res = LibrariesShortNames[Index];
   1403   return object_error::success;
   1404 }
   1405 
   1406 basic_symbol_iterator MachOObjectFile::symbol_begin_impl() const {
   1407   return getSymbolByIndex(0);
   1408 }
   1409 
   1410 basic_symbol_iterator MachOObjectFile::symbol_end_impl() const {
   1411   DataRefImpl DRI;
   1412   if (!SymtabLoadCmd)
   1413     return basic_symbol_iterator(SymbolRef(DRI, this));
   1414 
   1415   MachO::symtab_command Symtab = getSymtabLoadCommand();
   1416   unsigned SymbolTableEntrySize = is64Bit() ?
   1417     sizeof(MachO::nlist_64) :
   1418     sizeof(MachO::nlist);
   1419   unsigned Offset = Symtab.symoff +
   1420     Symtab.nsyms * SymbolTableEntrySize;
   1421   DRI.p = reinterpret_cast<uintptr_t>(getPtr(this, Offset));
   1422   return basic_symbol_iterator(SymbolRef(DRI, this));
   1423 }
   1424 
   1425 basic_symbol_iterator MachOObjectFile::getSymbolByIndex(unsigned Index) const {
   1426   DataRefImpl DRI;
   1427   if (!SymtabLoadCmd)
   1428     return basic_symbol_iterator(SymbolRef(DRI, this));
   1429 
   1430   MachO::symtab_command Symtab = getSymtabLoadCommand();
   1431   assert(Index < Symtab.nsyms && "Requested symbol index is out of range.");
   1432   unsigned SymbolTableEntrySize =
   1433     is64Bit() ? sizeof(MachO::nlist_64) : sizeof(MachO::nlist);
   1434   DRI.p = reinterpret_cast<uintptr_t>(getPtr(this, Symtab.symoff));
   1435   DRI.p += Index * SymbolTableEntrySize;
   1436   return basic_symbol_iterator(SymbolRef(DRI, this));
   1437 }
   1438 
   1439 section_iterator MachOObjectFile::section_begin() const {
   1440   DataRefImpl DRI;
   1441   return section_iterator(SectionRef(DRI, this));
   1442 }
   1443 
   1444 section_iterator MachOObjectFile::section_end() const {
   1445   DataRefImpl DRI;
   1446   DRI.d.a = Sections.size();
   1447   return section_iterator(SectionRef(DRI, this));
   1448 }
   1449 
   1450 library_iterator MachOObjectFile::needed_library_begin() const {
   1451   // TODO: implement
   1452   report_fatal_error("Needed libraries unimplemented in MachOObjectFile");
   1453 }
   1454 
   1455 library_iterator MachOObjectFile::needed_library_end() const {
   1456   // TODO: implement
   1457   report_fatal_error("Needed libraries unimplemented in MachOObjectFile");
   1458 }
   1459 
   1460 uint8_t MachOObjectFile::getBytesInAddress() const {
   1461   return is64Bit() ? 8 : 4;
   1462 }
   1463 
   1464 StringRef MachOObjectFile::getFileFormatName() const {
   1465   unsigned CPUType = getCPUType(this);
   1466   if (!is64Bit()) {
   1467     switch (CPUType) {
   1468     case llvm::MachO::CPU_TYPE_I386:
   1469       return "Mach-O 32-bit i386";
   1470     case llvm::MachO::CPU_TYPE_ARM:
   1471       return "Mach-O arm";
   1472     case llvm::MachO::CPU_TYPE_POWERPC:
   1473       return "Mach-O 32-bit ppc";
   1474     default:
   1475       assert((CPUType & llvm::MachO::CPU_ARCH_ABI64) == 0 &&
   1476              "64-bit object file when we're not 64-bit?");
   1477       return "Mach-O 32-bit unknown";
   1478     }
   1479   }
   1480 
   1481   // Make sure the cpu type has the correct mask.
   1482   assert((CPUType & llvm::MachO::CPU_ARCH_ABI64)
   1483          == llvm::MachO::CPU_ARCH_ABI64 &&
   1484          "32-bit object file when we're 64-bit?");
   1485 
   1486   switch (CPUType) {
   1487   case llvm::MachO::CPU_TYPE_X86_64:
   1488     return "Mach-O 64-bit x86-64";
   1489   case llvm::MachO::CPU_TYPE_ARM64:
   1490     return "Mach-O arm64";
   1491   case llvm::MachO::CPU_TYPE_POWERPC64:
   1492     return "Mach-O 64-bit ppc64";
   1493   default:
   1494     return "Mach-O 64-bit unknown";
   1495   }
   1496 }
   1497 
   1498 Triple::ArchType MachOObjectFile::getArch(uint32_t CPUType) {
   1499   switch (CPUType) {
   1500   case llvm::MachO::CPU_TYPE_I386:
   1501     return Triple::x86;
   1502   case llvm::MachO::CPU_TYPE_X86_64:
   1503     return Triple::x86_64;
   1504   case llvm::MachO::CPU_TYPE_ARM:
   1505     return Triple::arm;
   1506   case llvm::MachO::CPU_TYPE_ARM64:
   1507     return Triple::arm64;
   1508   case llvm::MachO::CPU_TYPE_POWERPC:
   1509     return Triple::ppc;
   1510   case llvm::MachO::CPU_TYPE_POWERPC64:
   1511     return Triple::ppc64;
   1512   default:
   1513     return Triple::UnknownArch;
   1514   }
   1515 }
   1516 
   1517 Triple MachOObjectFile::getArch(uint32_t CPUType, uint32_t CPUSubType) {
   1518   switch (CPUType) {
   1519   case MachO::CPU_TYPE_I386:
   1520     switch (CPUSubType & ~MachO::CPU_SUBTYPE_MASK) {
   1521     case MachO::CPU_SUBTYPE_I386_ALL:
   1522       return Triple("i386-apple-darwin");
   1523     default:
   1524       return Triple();
   1525     }
   1526   case MachO::CPU_TYPE_X86_64:
   1527     switch (CPUSubType & ~MachO::CPU_SUBTYPE_MASK) {
   1528     case MachO::CPU_SUBTYPE_X86_64_ALL:
   1529       return Triple("x86_64-apple-darwin");
   1530     case MachO::CPU_SUBTYPE_X86_64_H:
   1531       return Triple("x86_64h-apple-darwin");
   1532     default:
   1533       return Triple();
   1534     }
   1535   case MachO::CPU_TYPE_ARM:
   1536     switch (CPUSubType & ~MachO::CPU_SUBTYPE_MASK) {
   1537     case MachO::CPU_SUBTYPE_ARM_V4T:
   1538       return Triple("armv4t-apple-darwin");
   1539     case MachO::CPU_SUBTYPE_ARM_V5TEJ:
   1540       return Triple("armv5e-apple-darwin");
   1541     case MachO::CPU_SUBTYPE_ARM_V6:
   1542       return Triple("armv6-apple-darwin");
   1543     case MachO::CPU_SUBTYPE_ARM_V6M:
   1544       return Triple("armv6m-apple-darwin");
   1545     case MachO::CPU_SUBTYPE_ARM_V7EM:
   1546       return Triple("armv7em-apple-darwin");
   1547     case MachO::CPU_SUBTYPE_ARM_V7K:
   1548       return Triple("armv7k-apple-darwin");
   1549     case MachO::CPU_SUBTYPE_ARM_V7M:
   1550       return Triple("armv7m-apple-darwin");
   1551     case MachO::CPU_SUBTYPE_ARM_V7S:
   1552       return Triple("armv7s-apple-darwin");
   1553     default:
   1554       return Triple();
   1555     }
   1556   case MachO::CPU_TYPE_ARM64:
   1557     switch (CPUSubType & ~MachO::CPU_SUBTYPE_MASK) {
   1558     case MachO::CPU_SUBTYPE_ARM64_ALL:
   1559       return Triple("arm64-apple-darwin");
   1560     default:
   1561       return Triple();
   1562     }
   1563   case MachO::CPU_TYPE_POWERPC:
   1564     switch (CPUSubType & ~MachO::CPU_SUBTYPE_MASK) {
   1565     case MachO::CPU_SUBTYPE_POWERPC_ALL:
   1566       return Triple("ppc-apple-darwin");
   1567     default:
   1568       return Triple();
   1569     }
   1570   case MachO::CPU_TYPE_POWERPC64:
   1571     switch (CPUSubType & ~MachO::CPU_SUBTYPE_MASK) {
   1572     case MachO::CPU_SUBTYPE_POWERPC_ALL:
   1573       return Triple("ppc64-apple-darwin");
   1574     default:
   1575       return Triple();
   1576     }
   1577   default:
   1578     return Triple();
   1579   }
   1580 }
   1581 
   1582 Triple MachOObjectFile::getHostArch() {
   1583   return Triple(sys::getDefaultTargetTriple());
   1584 }
   1585 
   1586 Triple MachOObjectFile::getArch(StringRef ArchFlag) {
   1587   if (ArchFlag == "i386")
   1588     return Triple("i386-apple-darwin");
   1589   else if (ArchFlag == "x86_64")
   1590     return Triple("x86_64-apple-darwin");
   1591   else if (ArchFlag == "x86_64h")
   1592     return Triple("x86_64h-apple-darwin");
   1593   else if (ArchFlag == "armv4t" || ArchFlag == "arm")
   1594     return Triple("armv4t-apple-darwin");
   1595   else if (ArchFlag == "armv5e")
   1596     return Triple("armv5e-apple-darwin");
   1597   else if (ArchFlag == "armv6")
   1598     return Triple("armv6-apple-darwin");
   1599   else if (ArchFlag == "armv6m")
   1600     return Triple("armv6m-apple-darwin");
   1601   else if (ArchFlag == "armv7em")
   1602     return Triple("armv7em-apple-darwin");
   1603   else if (ArchFlag == "armv7k")
   1604     return Triple("armv7k-apple-darwin");
   1605   else if (ArchFlag == "armv7k")
   1606     return Triple("armv7m-apple-darwin");
   1607   else if (ArchFlag == "armv7s")
   1608     return Triple("armv7s-apple-darwin");
   1609   else if (ArchFlag == "arm64")
   1610     return Triple("arm64-apple-darwin");
   1611   else if (ArchFlag == "ppc")
   1612     return Triple("ppc-apple-darwin");
   1613   else if (ArchFlag == "ppc64")
   1614     return Triple("ppc64-apple-darwin");
   1615   else
   1616     return Triple();
   1617 }
   1618 
   1619 unsigned MachOObjectFile::getArch() const {
   1620   return getArch(getCPUType(this));
   1621 }
   1622 
   1623 StringRef MachOObjectFile::getLoadName() const {
   1624   // TODO: Implement
   1625   report_fatal_error("get_load_name() unimplemented in MachOObjectFile");
   1626 }
   1627 
   1628 relocation_iterator MachOObjectFile::section_rel_begin(unsigned Index) const {
   1629   DataRefImpl DRI;
   1630   DRI.d.a = Index;
   1631   return section_rel_begin(DRI);
   1632 }
   1633 
   1634 relocation_iterator MachOObjectFile::section_rel_end(unsigned Index) const {
   1635   DataRefImpl DRI;
   1636   DRI.d.a = Index;
   1637   return section_rel_end(DRI);
   1638 }
   1639 
   1640 dice_iterator MachOObjectFile::begin_dices() const {
   1641   DataRefImpl DRI;
   1642   if (!DataInCodeLoadCmd)
   1643     return dice_iterator(DiceRef(DRI, this));
   1644 
   1645   MachO::linkedit_data_command DicLC = getDataInCodeLoadCommand();
   1646   DRI.p = reinterpret_cast<uintptr_t>(getPtr(this, DicLC.dataoff));
   1647   return dice_iterator(DiceRef(DRI, this));
   1648 }
   1649 
   1650 dice_iterator MachOObjectFile::end_dices() const {
   1651   DataRefImpl DRI;
   1652   if (!DataInCodeLoadCmd)
   1653     return dice_iterator(DiceRef(DRI, this));
   1654 
   1655   MachO::linkedit_data_command DicLC = getDataInCodeLoadCommand();
   1656   unsigned Offset = DicLC.dataoff + DicLC.datasize;
   1657   DRI.p = reinterpret_cast<uintptr_t>(getPtr(this, Offset));
   1658   return dice_iterator(DiceRef(DRI, this));
   1659 }
   1660 
   1661 StringRef
   1662 MachOObjectFile::getSectionFinalSegmentName(DataRefImpl Sec) const {
   1663   ArrayRef<char> Raw = getSectionRawFinalSegmentName(Sec);
   1664   return parseSegmentOrSectionName(Raw.data());
   1665 }
   1666 
   1667 ArrayRef<char>
   1668 MachOObjectFile::getSectionRawName(DataRefImpl Sec) const {
   1669   const section_base *Base =
   1670     reinterpret_cast<const section_base *>(Sections[Sec.d.a]);
   1671   return ArrayRef<char>(Base->sectname);
   1672 }
   1673 
   1674 ArrayRef<char>
   1675 MachOObjectFile::getSectionRawFinalSegmentName(DataRefImpl Sec) const {
   1676   const section_base *Base =
   1677     reinterpret_cast<const section_base *>(Sections[Sec.d.a]);
   1678   return ArrayRef<char>(Base->segname);
   1679 }
   1680 
   1681 bool
   1682 MachOObjectFile::isRelocationScattered(const MachO::any_relocation_info &RE)
   1683   const {
   1684   if (getCPUType(this) == MachO::CPU_TYPE_X86_64)
   1685     return false;
   1686   return getPlainRelocationAddress(RE) & MachO::R_SCATTERED;
   1687 }
   1688 
   1689 unsigned MachOObjectFile::getPlainRelocationSymbolNum(
   1690     const MachO::any_relocation_info &RE) const {
   1691   if (isLittleEndian())
   1692     return RE.r_word1 & 0xffffff;
   1693   return RE.r_word1 >> 8;
   1694 }
   1695 
   1696 bool MachOObjectFile::getPlainRelocationExternal(
   1697     const MachO::any_relocation_info &RE) const {
   1698   if (isLittleEndian())
   1699     return (RE.r_word1 >> 27) & 1;
   1700   return (RE.r_word1 >> 4) & 1;
   1701 }
   1702 
   1703 bool MachOObjectFile::getScatteredRelocationScattered(
   1704     const MachO::any_relocation_info &RE) const {
   1705   return RE.r_word0 >> 31;
   1706 }
   1707 
   1708 uint32_t MachOObjectFile::getScatteredRelocationValue(
   1709     const MachO::any_relocation_info &RE) const {
   1710   return RE.r_word1;
   1711 }
   1712 
   1713 unsigned MachOObjectFile::getAnyRelocationAddress(
   1714     const MachO::any_relocation_info &RE) const {
   1715   if (isRelocationScattered(RE))
   1716     return getScatteredRelocationAddress(RE);
   1717   return getPlainRelocationAddress(RE);
   1718 }
   1719 
   1720 unsigned MachOObjectFile::getAnyRelocationPCRel(
   1721     const MachO::any_relocation_info &RE) const {
   1722   if (isRelocationScattered(RE))
   1723     return getScatteredRelocationPCRel(this, RE);
   1724   return getPlainRelocationPCRel(this, RE);
   1725 }
   1726 
   1727 unsigned MachOObjectFile::getAnyRelocationLength(
   1728     const MachO::any_relocation_info &RE) const {
   1729   if (isRelocationScattered(RE))
   1730     return getScatteredRelocationLength(RE);
   1731   return getPlainRelocationLength(this, RE);
   1732 }
   1733 
   1734 unsigned
   1735 MachOObjectFile::getAnyRelocationType(
   1736                                    const MachO::any_relocation_info &RE) const {
   1737   if (isRelocationScattered(RE))
   1738     return getScatteredRelocationType(RE);
   1739   return getPlainRelocationType(this, RE);
   1740 }
   1741 
   1742 SectionRef
   1743 MachOObjectFile::getRelocationSection(
   1744                                    const MachO::any_relocation_info &RE) const {
   1745   if (isRelocationScattered(RE) || getPlainRelocationExternal(RE))
   1746     return *section_end();
   1747   unsigned SecNum = getPlainRelocationSymbolNum(RE) - 1;
   1748   DataRefImpl DRI;
   1749   DRI.d.a = SecNum;
   1750   return SectionRef(DRI, this);
   1751 }
   1752 
   1753 MachOObjectFile::LoadCommandInfo
   1754 MachOObjectFile::getFirstLoadCommandInfo() const {
   1755   MachOObjectFile::LoadCommandInfo Load;
   1756 
   1757   unsigned HeaderSize = is64Bit() ? sizeof(MachO::mach_header_64) :
   1758                                     sizeof(MachO::mach_header);
   1759   Load.Ptr = getPtr(this, HeaderSize);
   1760   Load.C = getStruct<MachO::load_command>(this, Load.Ptr);
   1761   return Load;
   1762 }
   1763 
   1764 MachOObjectFile::LoadCommandInfo
   1765 MachOObjectFile::getNextLoadCommandInfo(const LoadCommandInfo &L) const {
   1766   MachOObjectFile::LoadCommandInfo Next;
   1767   Next.Ptr = L.Ptr + L.C.cmdsize;
   1768   Next.C = getStruct<MachO::load_command>(this, Next.Ptr);
   1769   return Next;
   1770 }
   1771 
   1772 MachO::section MachOObjectFile::getSection(DataRefImpl DRI) const {
   1773   return getStruct<MachO::section>(this, Sections[DRI.d.a]);
   1774 }
   1775 
   1776 MachO::section_64 MachOObjectFile::getSection64(DataRefImpl DRI) const {
   1777   return getStruct<MachO::section_64>(this, Sections[DRI.d.a]);
   1778 }
   1779 
   1780 MachO::section MachOObjectFile::getSection(const LoadCommandInfo &L,
   1781                                            unsigned Index) const {
   1782   const char *Sec = getSectionPtr(this, L, Index);
   1783   return getStruct<MachO::section>(this, Sec);
   1784 }
   1785 
   1786 MachO::section_64 MachOObjectFile::getSection64(const LoadCommandInfo &L,
   1787                                                 unsigned Index) const {
   1788   const char *Sec = getSectionPtr(this, L, Index);
   1789   return getStruct<MachO::section_64>(this, Sec);
   1790 }
   1791 
   1792 MachO::nlist
   1793 MachOObjectFile::getSymbolTableEntry(DataRefImpl DRI) const {
   1794   const char *P = reinterpret_cast<const char *>(DRI.p);
   1795   return getStruct<MachO::nlist>(this, P);
   1796 }
   1797 
   1798 MachO::nlist_64
   1799 MachOObjectFile::getSymbol64TableEntry(DataRefImpl DRI) const {
   1800   const char *P = reinterpret_cast<const char *>(DRI.p);
   1801   return getStruct<MachO::nlist_64>(this, P);
   1802 }
   1803 
   1804 MachO::linkedit_data_command
   1805 MachOObjectFile::getLinkeditDataLoadCommand(const LoadCommandInfo &L) const {
   1806   return getStruct<MachO::linkedit_data_command>(this, L.Ptr);
   1807 }
   1808 
   1809 MachO::segment_command
   1810 MachOObjectFile::getSegmentLoadCommand(const LoadCommandInfo &L) const {
   1811   return getStruct<MachO::segment_command>(this, L.Ptr);
   1812 }
   1813 
   1814 MachO::segment_command_64
   1815 MachOObjectFile::getSegment64LoadCommand(const LoadCommandInfo &L) const {
   1816   return getStruct<MachO::segment_command_64>(this, L.Ptr);
   1817 }
   1818 
   1819 MachO::linker_options_command
   1820 MachOObjectFile::getLinkerOptionsLoadCommand(const LoadCommandInfo &L) const {
   1821   return getStruct<MachO::linker_options_command>(this, L.Ptr);
   1822 }
   1823 
   1824 MachO::version_min_command
   1825 MachOObjectFile::getVersionMinLoadCommand(const LoadCommandInfo &L) const {
   1826   return getStruct<MachO::version_min_command>(this, L.Ptr);
   1827 }
   1828 
   1829 MachO::dylib_command
   1830 MachOObjectFile::getDylibIDLoadCommand(const LoadCommandInfo &L) const {
   1831   return getStruct<MachO::dylib_command>(this, L.Ptr);
   1832 }
   1833 
   1834 
   1835 MachO::any_relocation_info
   1836 MachOObjectFile::getRelocation(DataRefImpl Rel) const {
   1837   DataRefImpl Sec;
   1838   Sec.d.a = Rel.d.a;
   1839   uint32_t Offset;
   1840   if (is64Bit()) {
   1841     MachO::section_64 Sect = getSection64(Sec);
   1842     Offset = Sect.reloff;
   1843   } else {
   1844     MachO::section Sect = getSection(Sec);
   1845     Offset = Sect.reloff;
   1846   }
   1847 
   1848   auto P = reinterpret_cast<const MachO::any_relocation_info *>(
   1849       getPtr(this, Offset)) + Rel.d.b;
   1850   return getStruct<MachO::any_relocation_info>(
   1851       this, reinterpret_cast<const char *>(P));
   1852 }
   1853 
   1854 MachO::data_in_code_entry
   1855 MachOObjectFile::getDice(DataRefImpl Rel) const {
   1856   const char *P = reinterpret_cast<const char *>(Rel.p);
   1857   return getStruct<MachO::data_in_code_entry>(this, P);
   1858 }
   1859 
   1860 MachO::mach_header MachOObjectFile::getHeader() const {
   1861   return getStruct<MachO::mach_header>(this, getPtr(this, 0));
   1862 }
   1863 
   1864 MachO::mach_header_64 MachOObjectFile::getHeader64() const {
   1865   return getStruct<MachO::mach_header_64>(this, getPtr(this, 0));
   1866 }
   1867 
   1868 uint32_t MachOObjectFile::getIndirectSymbolTableEntry(
   1869                                              const MachO::dysymtab_command &DLC,
   1870                                              unsigned Index) const {
   1871   uint64_t Offset = DLC.indirectsymoff + Index * sizeof(uint32_t);
   1872   return getStruct<uint32_t>(this, getPtr(this, Offset));
   1873 }
   1874 
   1875 MachO::data_in_code_entry
   1876 MachOObjectFile::getDataInCodeTableEntry(uint32_t DataOffset,
   1877                                          unsigned Index) const {
   1878   uint64_t Offset = DataOffset + Index * sizeof(MachO::data_in_code_entry);
   1879   return getStruct<MachO::data_in_code_entry>(this, getPtr(this, Offset));
   1880 }
   1881 
   1882 MachO::symtab_command MachOObjectFile::getSymtabLoadCommand() const {
   1883   return getStruct<MachO::symtab_command>(this, SymtabLoadCmd);
   1884 }
   1885 
   1886 MachO::dysymtab_command MachOObjectFile::getDysymtabLoadCommand() const {
   1887   return getStruct<MachO::dysymtab_command>(this, DysymtabLoadCmd);
   1888 }
   1889 
   1890 MachO::linkedit_data_command
   1891 MachOObjectFile::getDataInCodeLoadCommand() const {
   1892   if (DataInCodeLoadCmd)
   1893     return getStruct<MachO::linkedit_data_command>(this, DataInCodeLoadCmd);
   1894 
   1895   // If there is no DataInCodeLoadCmd return a load command with zero'ed fields.
   1896   MachO::linkedit_data_command Cmd;
   1897   Cmd.cmd = MachO::LC_DATA_IN_CODE;
   1898   Cmd.cmdsize = sizeof(MachO::linkedit_data_command);
   1899   Cmd.dataoff = 0;
   1900   Cmd.datasize = 0;
   1901   return Cmd;
   1902 }
   1903 
   1904 StringRef MachOObjectFile::getStringTableData() const {
   1905   MachO::symtab_command S = getSymtabLoadCommand();
   1906   return getData().substr(S.stroff, S.strsize);
   1907 }
   1908 
   1909 bool MachOObjectFile::is64Bit() const {
   1910   return getType() == getMachOType(false, true) ||
   1911          getType() == getMachOType(true, true);
   1912 }
   1913 
   1914 void MachOObjectFile::ReadULEB128s(uint64_t Index,
   1915                                    SmallVectorImpl<uint64_t> &Out) const {
   1916   DataExtractor extractor(ObjectFile::getData(), true, 0);
   1917 
   1918   uint32_t offset = Index;
   1919   uint64_t data = 0;
   1920   while (uint64_t delta = extractor.getULEB128(&offset)) {
   1921     data += delta;
   1922     Out.push_back(data);
   1923   }
   1924 }
   1925 
   1926 const char *MachOObjectFile::getSectionPointer(DataRefImpl Rel) const {
   1927   return Sections[Rel.d.a];
   1928 }
   1929 
   1930 ErrorOr<ObjectFile *>
   1931 ObjectFile::createMachOObjectFile(std::unique_ptr<MemoryBuffer> &Buffer) {
   1932   StringRef Magic = Buffer->getBuffer().slice(0, 4);
   1933   std::error_code EC;
   1934   std::unique_ptr<MachOObjectFile> Ret;
   1935   if (Magic == "\xFE\xED\xFA\xCE")
   1936     Ret.reset(new MachOObjectFile(std::move(Buffer), false, false, EC));
   1937   else if (Magic == "\xCE\xFA\xED\xFE")
   1938     Ret.reset(new MachOObjectFile(std::move(Buffer), true, false, EC));
   1939   else if (Magic == "\xFE\xED\xFA\xCF")
   1940     Ret.reset(new MachOObjectFile(std::move(Buffer), false, true, EC));
   1941   else if (Magic == "\xCF\xFA\xED\xFE")
   1942     Ret.reset(new MachOObjectFile(std::move(Buffer), true, true, EC));
   1943   else
   1944     return object_error::parse_failed;
   1945 
   1946   if (EC)
   1947     return EC;
   1948   return Ret.release();
   1949 }
   1950 
   1951 } // end namespace object
   1952 } // end namespace llvm
   1953