Detect invalid section indexes when we first read them.
[oota-llvm.git] / lib / Object / MachOObjectFile.cpp
index 2409314e12cbc97d04d4eadf494f42696139421f..504b3172c9d10c591f9ca374c7977188140b0e14 100644 (file)
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Object/MachO.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/Support/DataExtractor.h"
+#include "llvm/Support/Debug.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/Host.h"
+#include "llvm/Support/LEB128.h"
+#include "llvm/Support/MachO.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cctype>
 using namespace llvm;
 using namespace object;
 
-namespace llvm {
-namespace object {
-
-struct nlist_base {
-  uint32_t n_strx;
-  uint8_t n_type;
-  uint8_t n_sect;
-  uint16_t n_desc;
-};
-
-struct section_base {
-  char sectname[16];
-  char segname[16];
-};
-
-template<typename T>
-static void SwapValue(T &Value) {
-  Value = sys::SwapByteOrder(Value);
-}
-
-template<typename T>
-static void SwapStruct(T &Value);
-
-template<>
-void SwapStruct(MachO::any_relocation_info &H) {
-  SwapValue(H.r_word0);
-  SwapValue(H.r_word1);
-}
-
-template<>
-void SwapStruct(MachO::load_command &L) {
-  SwapValue(L.cmd);
-  SwapValue(L.cmdsize);
-}
-
-template<>
-void SwapStruct(nlist_base &S) {
-  SwapValue(S.n_strx);
-  SwapValue(S.n_desc);
-}
-
-template<>
-void SwapStruct(MachO::section &S) {
-  SwapValue(S.addr);
-  SwapValue(S.size);
-  SwapValue(S.offset);
-  SwapValue(S.align);
-  SwapValue(S.reloff);
-  SwapValue(S.nreloc);
-  SwapValue(S.flags);
-  SwapValue(S.reserved1);
-  SwapValue(S.reserved2);
-}
-
-template<>
-void SwapStruct(MachO::section_64 &S) {
-  SwapValue(S.addr);
-  SwapValue(S.size);
-  SwapValue(S.offset);
-  SwapValue(S.align);
-  SwapValue(S.reloff);
-  SwapValue(S.nreloc);
-  SwapValue(S.flags);
-  SwapValue(S.reserved1);
-  SwapValue(S.reserved2);
-  SwapValue(S.reserved3);
-}
-
-template<>
-void SwapStruct(MachO::nlist &S) {
-  SwapValue(S.n_strx);
-  SwapValue(S.n_desc);
-  SwapValue(S.n_value);
-}
-
-template<>
-void SwapStruct(MachO::nlist_64 &S) {
-  SwapValue(S.n_strx);
-  SwapValue(S.n_desc);
-  SwapValue(S.n_value);
-}
-
-template<>
-void SwapStruct(MachO::mach_header &H) {
-  SwapValue(H.magic);
-  SwapValue(H.cputype);
-  SwapValue(H.cpusubtype);
-  SwapValue(H.filetype);
-  SwapValue(H.ncmds);
-  SwapValue(H.sizeofcmds);
-  SwapValue(H.flags);
-}
-
-template<>
-void SwapStruct(MachO::mach_header_64 &H) {
-  SwapValue(H.magic);
-  SwapValue(H.cputype);
-  SwapValue(H.cpusubtype);
-  SwapValue(H.filetype);
-  SwapValue(H.ncmds);
-  SwapValue(H.sizeofcmds);
-  SwapValue(H.flags);
-  SwapValue(H.reserved);
-}
-
-template<>
-void SwapStruct(MachO::symtab_command &C) {
-  SwapValue(C.cmd);
-  SwapValue(C.cmdsize);
-  SwapValue(C.symoff);
-  SwapValue(C.nsyms);
-  SwapValue(C.stroff);
-  SwapValue(C.strsize);
-}
-
-template<>
-void SwapStruct(MachO::dysymtab_command &C) {
-  SwapValue(C.cmd);
-  SwapValue(C.cmdsize);
-  SwapValue(C.ilocalsym);
-  SwapValue(C.nlocalsym);
-  SwapValue(C.iextdefsym);
-  SwapValue(C.nextdefsym);
-  SwapValue(C.iundefsym);
-  SwapValue(C.nundefsym);
-  SwapValue(C.tocoff);
-  SwapValue(C.ntoc);
-  SwapValue(C.modtaboff);
-  SwapValue(C.nmodtab);
-  SwapValue(C.extrefsymoff);
-  SwapValue(C.nextrefsyms);
-  SwapValue(C.indirectsymoff);
-  SwapValue(C.nindirectsyms);
-  SwapValue(C.extreloff);
-  SwapValue(C.nextrel);
-  SwapValue(C.locreloff);
-  SwapValue(C.nlocrel);
-}
-
-template<>
-void SwapStruct(MachO::linkedit_data_command &C) {
-  SwapValue(C.cmd);
-  SwapValue(C.cmdsize);
-  SwapValue(C.dataoff);
-  SwapValue(C.datasize);
-}
-
-template<>
-void SwapStruct(MachO::segment_command &C) {
-  SwapValue(C.cmd);
-  SwapValue(C.cmdsize);
-  SwapValue(C.vmaddr);
-  SwapValue(C.vmsize);
-  SwapValue(C.fileoff);
-  SwapValue(C.filesize);
-  SwapValue(C.maxprot);
-  SwapValue(C.initprot);
-  SwapValue(C.nsects);
-  SwapValue(C.flags);
-}
-
-template<>
-void SwapStruct(MachO::segment_command_64 &C) {
-  SwapValue(C.cmd);
-  SwapValue(C.cmdsize);
-  SwapValue(C.vmaddr);
-  SwapValue(C.vmsize);
-  SwapValue(C.fileoff);
-  SwapValue(C.filesize);
-  SwapValue(C.maxprot);
-  SwapValue(C.initprot);
-  SwapValue(C.nsects);
-  SwapValue(C.flags);
-}
-
-template<>
-void SwapStruct(uint32_t &C) {
-  SwapValue(C);
-}
-
-template<>
-void SwapStruct(MachO::linker_options_command &C) {
-  SwapValue(C.cmd);
-  SwapValue(C.cmdsize);
-  SwapValue(C.count);
-}
-
-template<>
-void SwapStruct(MachO::data_in_code_entry &C) {
-  SwapValue(C.offset);
-  SwapValue(C.length);
-  SwapValue(C.kind);
-}
-
-template<typename T>
-T getStruct(const MachOObjectFile *O, const char *P) {
+namespace {
+  struct section_base {
+    char sectname[16];
+    char segname[16];
+  };
+}
+
+template <typename T>
+static T getStruct(const MachOObjectFile *O, const char *P) {
+  // Don't read before the beginning or past the end of the file
+  if (P < O->getData().begin() || P + sizeof(T) > O->getData().end())
+    report_fatal_error("Malformed MachO file.");
+
   T Cmd;
   memcpy(&Cmd, P, sizeof(T));
   if (O->isLittleEndian() != sys::IsLittleEndianHost)
-    SwapStruct(Cmd);
+    MachO::swapStruct(Cmd);
   return Cmd;
 }
 
+template <typename SegmentCmd>
+static uint32_t getSegmentLoadCommandNumSections(const SegmentCmd &S,
+                                                 uint32_t Cmdsize) {
+  const unsigned SectionSize = sizeof(SegmentCmd);
+  if (S.nsects > std::numeric_limits<uint32_t>::max() / SectionSize ||
+      S.nsects * SectionSize > Cmdsize - sizeof(S))
+    report_fatal_error(
+        "Number of sections too large for size of load command.");
+  return S.nsects;
+}
+
 static uint32_t
 getSegmentLoadCommandNumSections(const MachOObjectFile *O,
                                  const MachOObjectFile::LoadCommandInfo &L) {
+  if (O->is64Bit())
+    return getSegmentLoadCommandNumSections(O->getSegment64LoadCommand(L),
+                                            L.C.cmdsize);
+
+  return getSegmentLoadCommandNumSections(O->getSegmentLoadCommand(L),
+                                          L.C.cmdsize);
+}
+
+static bool isPageZeroSegment(const MachOObjectFile *O,
+                              const MachOObjectFile::LoadCommandInfo &L) {
   if (O->is64Bit()) {
     MachO::segment_command_64 S = O->getSegment64LoadCommand(L);
-    return S.nsects;
+    return StringRef("__PAGEZERO").equals(S.segname);
   }
   MachO::segment_command S = O->getSegmentLoadCommand(L);
-  return S.nsects;
+  return StringRef("__PAGEZERO").equals(S.segname);
 }
 
+
 static const char *
 getSectionPtr(const MachOObjectFile *O, MachOObjectFile::LoadCommandInfo L,
               unsigned Sec) {
@@ -259,10 +103,10 @@ static const char *getPtr(const MachOObjectFile *O, size_t Offset) {
   return O->getData().substr(Offset, 1).data();
 }
 
-static nlist_base
+static MachO::nlist_base
 getSymbolTableEntryBase(const MachOObjectFile *O, DataRefImpl DRI) {
   const char *P = reinterpret_cast<const char *>(DRI.p);
-  return getStruct<nlist_base>(O, P);
+  return getStruct<MachO::nlist_base>(O, P);
 }
 
 static StringRef parseSegmentOrSectionName(const char *P) {
@@ -275,18 +119,9 @@ static StringRef parseSegmentOrSectionName(const char *P) {
 
 // Helper to advance a section or symbol iterator multiple increments at a time.
 template<class T>
-static error_code advance(T &it, size_t Val) {
-  error_code ec;
-  while (Val--) {
-    it.increment(ec);
-  }
-  return ec;
-}
-
-template<class T>
-static void advanceTo(T &it, size_t Val) {
-  if (error_code ec = advance(it, Val))
-    report_fatal_error(ec.message());
+static void advance(T &it, size_t Val) {
+  while (Val--)
+    ++it;
 }
 
 static unsigned getCPUType(const MachOObjectFile *O) {
@@ -305,18 +140,16 @@ static void printRelocationTargetName(const MachOObjectFile *O,
   if (IsScattered) {
     uint32_t Val = O->getPlainRelocationSymbolNum(RE);
 
-    error_code ec;
-    for (symbol_iterator SI = O->begin_symbols(), SE = O->end_symbols();
-         SI != SE; SI.increment(ec)) {
-      if (ec) report_fatal_error(ec.message());
-
+    for (const SymbolRef &Symbol : O->symbols()) {
+      std::error_code ec;
       uint64_t Addr;
       StringRef Name;
 
-      if ((ec = SI->getAddress(Addr)))
+      if ((ec = Symbol.getAddress(Addr)))
         report_fatal_error(ec.message());
-      if (Addr != Val) continue;
-      if ((ec = SI->getName(Name)))
+      if (Addr != Val)
+        continue;
+      if ((ec = Symbol.getName(Name)))
         report_fatal_error(ec.message());
       fmt << Name;
       return;
@@ -324,17 +157,14 @@ static void printRelocationTargetName(const MachOObjectFile *O,
 
     // If we couldn't find a symbol that this relocation refers to, try
     // to find a section beginning instead.
-    for (section_iterator SI = O->begin_sections(), SE = O->end_sections();
-         SI != SE; SI.increment(ec)) {
-      if (ec) report_fatal_error(ec.message());
+    for (const SectionRef &Section : O->sections()) {
+      std::error_code ec;
 
-      uint64_t Addr;
       StringRef Name;
-
-      if ((ec = SI->getAddress(Addr)))
-        report_fatal_error(ec.message());
-      if (Addr != Val) continue;
-      if ((ec = SI->getName(Name)))
+      uint64_t Addr = Section.getAddress();
+      if (Addr != Val)
+        continue;
+      if ((ec = Section.getName(Name)))
         report_fatal_error(ec.message());
       fmt << Name;
       return;
@@ -349,13 +179,13 @@ static void printRelocationTargetName(const MachOObjectFile *O,
   uint64_t Val = O->getPlainRelocationSymbolNum(RE);
 
   if (isExtern) {
-    symbol_iterator SI = O->begin_symbols();
-    advanceTo(SI, Val);
+    symbol_iterator SI = O->symbol_begin();
+    advance(SI, Val);
     SI->getName(S);
   } else {
-    section_iterator SI = O->begin_sections();
+    section_iterator SI = O->section_begin();
     // Adjust for the fact that sections are 1-indexed.
-    advanceTo(SI, Val - 1);
+    advance(SI, Val - 1);
     SI->getName(S);
   }
 
@@ -404,11 +234,6 @@ static unsigned getPlainRelocationType(const MachOObjectFile *O,
   return RE.r_word1 & 0xf;
 }
 
-static unsigned
-getScatteredRelocationType(const MachO::any_relocation_info &RE) {
-  return (RE.r_word0 >> 24) & 0xf;
-}
-
 static uint32_t getSectionFlags(const MachOObjectFile *O,
                                 DataRefImpl Sec) {
   if (O->is64Bit()) {
@@ -419,32 +244,85 @@ static uint32_t getSectionFlags(const MachOObjectFile *O,
   return Sect.flags;
 }
 
-MachOObjectFile::MachOObjectFile(MemoryBuffer *Object, bool IsLittleEndian,
-                                 bool Is64bits, error_code &EC,
-                                 bool BufferOwned)
-    : ObjectFile(getMachOType(IsLittleEndian, Is64bits), Object, BufferOwned),
-      SymtabLoadCmd(NULL), DysymtabLoadCmd(NULL), DataInCodeLoadCmd(NULL) {
+MachOObjectFile::MachOObjectFile(MemoryBufferRef Object, bool IsLittleEndian,
+                                 bool Is64bits, std::error_code &EC)
+    : ObjectFile(getMachOType(IsLittleEndian, Is64bits), Object),
+      SymtabLoadCmd(nullptr), DysymtabLoadCmd(nullptr),
+      DataInCodeLoadCmd(nullptr), LinkOptHintsLoadCmd(nullptr),
+      DyldInfoLoadCmd(nullptr), UuidLoadCmd(nullptr),
+      HasPageZeroSegment(false) {
   uint32_t LoadCommandCount = this->getHeader().ncmds;
+  if (LoadCommandCount == 0)
+    return;
+
   MachO::LoadCommandType SegmentLoadType = is64Bit() ?
     MachO::LC_SEGMENT_64 : MachO::LC_SEGMENT;
 
   MachOObjectFile::LoadCommandInfo Load = getFirstLoadCommandInfo();
   for (unsigned I = 0; ; ++I) {
     if (Load.C.cmd == MachO::LC_SYMTAB) {
-      assert(!SymtabLoadCmd && "Multiple symbol tables");
+      // Multiple symbol tables
+      if (SymtabLoadCmd) {
+        EC = object_error::parse_failed;
+        return;
+      }
       SymtabLoadCmd = Load.Ptr;
     } else if (Load.C.cmd == MachO::LC_DYSYMTAB) {
-      assert(!DysymtabLoadCmd && "Multiple dynamic symbol tables");
+      // Multiple dynamic symbol tables
+      if (DysymtabLoadCmd) {
+        EC = object_error::parse_failed;
+        return;
+      }
       DysymtabLoadCmd = Load.Ptr;
     } else if (Load.C.cmd == MachO::LC_DATA_IN_CODE) {
-      assert(!DataInCodeLoadCmd && "Multiple data in code tables");
+      // Multiple data in code tables
+      if (DataInCodeLoadCmd) {
+        EC = object_error::parse_failed;
+        return;
+      }
       DataInCodeLoadCmd = Load.Ptr;
+    } else if (Load.C.cmd == MachO::LC_LINKER_OPTIMIZATION_HINT) {
+      // Multiple linker optimization hint tables
+      if (LinkOptHintsLoadCmd) {
+        EC = object_error::parse_failed;
+        return;
+      }
+      LinkOptHintsLoadCmd = Load.Ptr;
+    } else if (Load.C.cmd == MachO::LC_DYLD_INFO || 
+               Load.C.cmd == MachO::LC_DYLD_INFO_ONLY) {
+      // Multiple dyldinfo load commands
+      if (DyldInfoLoadCmd) {
+        EC = object_error::parse_failed;
+        return;
+      }
+      DyldInfoLoadCmd = Load.Ptr;
+    } else if (Load.C.cmd == MachO::LC_UUID) {
+      // Multiple UUID load commands
+      if (UuidLoadCmd) {
+        EC = object_error::parse_failed;
+        return;
+      }
+      UuidLoadCmd = Load.Ptr;
     } else if (Load.C.cmd == SegmentLoadType) {
+      const unsigned SegmentLoadSize = this->is64Bit()
+                                           ? sizeof(MachO::segment_command_64)
+                                           : sizeof(MachO::segment_command);
+      if (Load.C.cmdsize < SegmentLoadSize)
+        report_fatal_error("Segment load command size is too small.");
+
       uint32_t NumSections = getSegmentLoadCommandNumSections(this, Load);
       for (unsigned J = 0; J < NumSections; ++J) {
         const char *Sec = getSectionPtr(this, Load, J);
         Sections.push_back(Sec);
       }
+      if (isPageZeroSegment(this, Load))
+        HasPageZeroSegment = true;
+    } else if (Load.C.cmd == MachO::LC_LOAD_DYLIB ||
+               Load.C.cmd == MachO::LC_LOAD_WEAK_DYLIB ||
+               Load.C.cmd == MachO::LC_LAZY_LOAD_DYLIB ||
+               Load.C.cmd == MachO::LC_REEXPORT_DYLIB ||
+               Load.C.cmd == MachO::LC_LOAD_UPWARD_DYLIB) {
+      Libraries.push_back(Load.Ptr);
     }
 
     if (I == LoadCommandCount - 1)
@@ -454,66 +332,80 @@ MachOObjectFile::MachOObjectFile(MemoryBuffer *Object, bool IsLittleEndian,
   }
 }
 
-error_code MachOObjectFile::getSymbolNext(DataRefImpl Symb,
-                                          SymbolRef &Res) const {
+void MachOObjectFile::moveSymbolNext(DataRefImpl &Symb) const {
   unsigned SymbolTableEntrySize = is64Bit() ?
     sizeof(MachO::nlist_64) :
     sizeof(MachO::nlist);
   Symb.p += SymbolTableEntrySize;
-  Res = SymbolRef(Symb, this);
-  return object_error::success;
 }
 
-error_code MachOObjectFile::getSymbolName(DataRefImpl Symb,
-                                          StringRef &Res) const {
+std::error_code MachOObjectFile::getSymbolName(DataRefImpl Symb,
+                                               StringRef &Res) const {
   StringRef StringTable = getStringTableData();
-  nlist_base Entry = getSymbolTableEntryBase(this, Symb);
+  MachO::nlist_base Entry = getSymbolTableEntryBase(this, Symb);
   const char *Start = &StringTable.data()[Entry.n_strx];
+  if (Start < getData().begin() || Start >= getData().end())
+    report_fatal_error(
+        "Symbol name entry points before beginning or past end of file.");
   Res = StringRef(Start);
   return object_error::success;
 }
 
-error_code MachOObjectFile::getSymbolAddress(DataRefImpl Symb,
-                                             uint64_t &Res) const {
+unsigned MachOObjectFile::getSectionType(SectionRef Sec) const {
+  DataRefImpl DRI = Sec.getRawDataRefImpl();
+  uint32_t Flags = getSectionFlags(this, DRI);
+  return Flags & MachO::SECTION_TYPE;
+}
+
+// getIndirectName() returns the name of the alias'ed symbol who's string table
+// index is in the n_value field.
+std::error_code MachOObjectFile::getIndirectName(DataRefImpl Symb,
+                                                 StringRef &Res) const {
+  StringRef StringTable = getStringTableData();
+  uint64_t NValue;
   if (is64Bit()) {
     MachO::nlist_64 Entry = getSymbol64TableEntry(Symb);
-    Res = Entry.n_value;
+    NValue = Entry.n_value;
+    if ((Entry.n_type & MachO::N_TYPE) != MachO::N_INDR)
+      return object_error::parse_failed;
   } else {
     MachO::nlist Entry = getSymbolTableEntry(Symb);
-    Res = Entry.n_value;
+    NValue = Entry.n_value;
+    if ((Entry.n_type & MachO::N_TYPE) != MachO::N_INDR)
+      return object_error::parse_failed;
   }
+  if (NValue >= StringTable.size())
+    return object_error::parse_failed;
+  const char *Start = &StringTable.data()[NValue];
+  Res = StringRef(Start);
   return object_error::success;
 }
 
-error_code
-MachOObjectFile::getSymbolFileOffset(DataRefImpl Symb,
-                                     uint64_t &Res) const {
-  nlist_base Entry = getSymbolTableEntryBase(this, Symb);
-  getSymbolAddress(Symb, Res);
-  if (Entry.n_sect) {
-    uint64_t Delta;
-    DataRefImpl SecRel;
-    SecRel.d.a = Entry.n_sect-1;
-    if (is64Bit()) {
-      MachO::section_64 Sec = getSection64(SecRel);
-      Delta = Sec.offset - Sec.addr;
-    } else {
-      MachO::section Sec = getSection(SecRel);
-      Delta = Sec.offset - Sec.addr;
-    }
-
-    Res += Delta;
+std::error_code MachOObjectFile::getSymbolAddress(DataRefImpl Symb,
+                                                  uint64_t &Res) const {
+  if (is64Bit()) {
+    MachO::nlist_64 Entry = getSymbol64TableEntry(Symb);
+    if ((Entry.n_type & MachO::N_TYPE) == MachO::N_UNDF &&
+        Entry.n_value == 0)
+      Res = UnknownAddressOrSize;
+    else
+      Res = Entry.n_value;
+  } else {
+    MachO::nlist Entry = getSymbolTableEntry(Symb);
+    if ((Entry.n_type & MachO::N_TYPE) == MachO::N_UNDF &&
+        Entry.n_value == 0)
+      Res = UnknownAddressOrSize;
+    else
+      Res = Entry.n_value;
   }
-
   return object_error::success;
 }
 
-error_code MachOObjectFile::getSymbolAlignment(DataRefImpl DRI,
-                                               uint32_t &Result) const {
-  uint32_t flags;
-  this->getSymbolFlags(DRI, flags);
+std::error_code MachOObjectFile::getSymbolAlignment(DataRefImpl DRI,
+                                                    uint32_t &Result) const {
+  uint32_t flags = getSymbolFlags(DRI);
   if (flags & SymbolRef::SF_Common) {
-    nlist_base Entry = getSymbolTableEntryBase(this, DRI);
+    MachO::nlist_base Entry = getSymbolTableEntryBase(this, DRI);
     Result = 1 << MachO::GET_COMM_ALIGN(Entry.n_desc);
   } else {
     Result = 0;
@@ -521,22 +413,25 @@ error_code MachOObjectFile::getSymbolAlignment(DataRefImpl DRI,
   return object_error::success;
 }
 
-error_code MachOObjectFile::getSymbolSize(DataRefImpl DRI,
-                                          uint64_t &Result) const {
+std::error_code MachOObjectFile::getSymbolSize(DataRefImpl DRI,
+                                               uint64_t &Result) const {
   uint64_t BeginOffset;
   uint64_t EndOffset = 0;
   uint8_t SectionIndex;
 
-  nlist_base Entry = getSymbolTableEntryBase(this, DRI);
+  MachO::nlist_base Entry = getSymbolTableEntryBase(this, DRI);
   uint64_t Value;
   getSymbolAddress(DRI, Value);
+  if (Value == UnknownAddressOrSize) {
+    Result = UnknownAddressOrSize;
+    return object_error::success;
+  }
 
   BeginOffset = Value;
 
   SectionIndex = Entry.n_sect;
   if (!SectionIndex) {
-    uint32_t flags = SymbolRef::SF_None;
-    this->getSymbolFlags(DRI, flags);
+    uint32_t flags = getSymbolFlags(DRI);
     if (flags & SymbolRef::SF_Common)
       Result = Value;
     else
@@ -545,31 +440,30 @@ error_code MachOObjectFile::getSymbolSize(DataRefImpl DRI,
   }
   // Unfortunately symbols are unsorted so we need to touch all
   // symbols from load command
-  error_code ec;
-  for (symbol_iterator I = begin_symbols(), E = end_symbols(); I != E;
-       I.increment(ec)) {
-    DataRefImpl DRI = I->getRawDataRefImpl();
+  for (const SymbolRef &Symbol : symbols()) {
+    DataRefImpl DRI = Symbol.getRawDataRefImpl();
     Entry = getSymbolTableEntryBase(this, DRI);
     getSymbolAddress(DRI, Value);
+    if (Value == UnknownAddressOrSize)
+      continue;
     if (Entry.n_sect == SectionIndex && Value > BeginOffset)
       if (!EndOffset || Value < EndOffset)
         EndOffset = Value;
   }
   if (!EndOffset) {
-    uint64_t Size;
     DataRefImpl Sec;
     Sec.d.a = SectionIndex-1;
-    getSectionSize(Sec, Size);
-    getSectionAddress(Sec, EndOffset);
+    uint64_t Size = getSectionSize(Sec);
+    EndOffset = getSectionAddress(Sec);
     EndOffset += Size;
   }
   Result = EndOffset - BeginOffset;
   return object_error::success;
 }
 
-error_code MachOObjectFile::getSymbolType(DataRefImpl Symb,
-                                          SymbolRef::Type &Res) const {
-  nlist_base Entry = getSymbolTableEntryBase(this, Symb);
+std::error_code MachOObjectFile::getSymbolType(DataRefImpl Symb,
+                                               SymbolRef::Type &Res) const {
+  MachO::nlist_base Entry = getSymbolTableEntryBase(this, Symb);
   uint8_t n_type = Entry.n_type;
 
   Res = SymbolRef::ST_Other;
@@ -591,19 +485,20 @@ error_code MachOObjectFile::getSymbolType(DataRefImpl Symb,
   return object_error::success;
 }
 
-error_code MachOObjectFile::getSymbolFlags(DataRefImpl DRI,
-                                           uint32_t &Result) const {
-  nlist_base Entry = getSymbolTableEntryBase(this, DRI);
+uint32_t MachOObjectFile::getSymbolFlags(DataRefImpl DRI) const {
+  MachO::nlist_base Entry = getSymbolTableEntryBase(this, DRI);
 
   uint8_t MachOType = Entry.n_type;
   uint16_t MachOFlags = Entry.n_desc;
 
-  // TODO: Correctly set SF_ThreadLocal
-  Result = SymbolRef::SF_None;
+  uint32_t Result = SymbolRef::SF_None;
 
   if ((MachOType & MachO::N_TYPE) == MachO::N_UNDF)
     Result |= SymbolRef::SF_Undefined;
 
+  if ((MachOType & MachO::N_TYPE) == MachO::N_INDR)
+    Result |= SymbolRef::SF_Indirect;
+
   if (MachOType & MachO::N_STAB)
     Result |= SymbolRef::SF_FormatSpecific;
 
@@ -612,83 +507,69 @@ error_code MachOObjectFile::getSymbolFlags(DataRefImpl DRI,
     if ((MachOType & MachO::N_TYPE) == MachO::N_UNDF) {
       uint64_t Value;
       getSymbolAddress(DRI, Value);
-      if (Value)
+      if (Value && Value != UnknownAddressOrSize)
         Result |= SymbolRef::SF_Common;
     }
+
+    if (!(MachOType & MachO::N_PEXT))
+      Result |= SymbolRef::SF_Exported;
   }
 
   if (MachOFlags & (MachO::N_WEAK_REF | MachO::N_WEAK_DEF))
     Result |= SymbolRef::SF_Weak;
 
+  if (MachOFlags & (MachO::N_ARM_THUMB_DEF))
+    Result |= SymbolRef::SF_Thumb;
+
   if ((MachOType & MachO::N_TYPE) == MachO::N_ABS)
     Result |= SymbolRef::SF_Absolute;
 
-  return object_error::success;
+  return Result;
 }
 
-error_code
-MachOObjectFile::getSymbolSection(DataRefImpl Symb,
-                                  section_iterator &Res) const {
-  nlist_base Entry = getSymbolTableEntryBase(this, Symb);
+std::error_code MachOObjectFile::getSymbolSection(DataRefImpl Symb,
+                                                  section_iterator &Res) const {
+  MachO::nlist_base Entry = getSymbolTableEntryBase(this, Symb);
   uint8_t index = Entry.n_sect;
 
   if (index == 0) {
-    Res = end_sections();
+    Res = section_end();
   } else {
     DataRefImpl DRI;
     DRI.d.a = index - 1;
+    if (DRI.d.a >= Sections.size())
+      report_fatal_error("getSymbolSection: Invalid section index.");
     Res = section_iterator(SectionRef(DRI, this));
   }
 
   return object_error::success;
 }
 
-error_code MachOObjectFile::getSymbolValue(DataRefImpl Symb,
-                                           uint64_t &Val) const {
-  report_fatal_error("getSymbolValue unimplemented in MachOObjectFile");
-}
-
-error_code MachOObjectFile::getSectionNext(DataRefImpl Sec,
-                                           SectionRef &Res) const {
+void MachOObjectFile::moveSectionNext(DataRefImpl &Sec) const {
   Sec.d.a++;
-  Res = SectionRef(Sec, this);
-  return object_error::success;
 }
 
-error_code
-MachOObjectFile::getSectionName(DataRefImpl Sec, StringRef &Result) const {
+std::error_code MachOObjectFile::getSectionName(DataRefImpl Sec,
+                                                StringRef &Result) const {
   ArrayRef<char> Raw = getSectionRawName(Sec);
   Result = parseSegmentOrSectionName(Raw.data());
   return object_error::success;
 }
 
-error_code
-MachOObjectFile::getSectionAddress(DataRefImpl Sec, uint64_t &Res) const {
-  if (is64Bit()) {
-    MachO::section_64 Sect = getSection64(Sec);
-    Res = Sect.addr;
-  } else {
-    MachO::section Sect = getSection(Sec);
-    Res = Sect.addr;
-  }
-  return object_error::success;
+uint64_t MachOObjectFile::getSectionAddress(DataRefImpl Sec) const {
+  if (is64Bit())
+    return getSection64(Sec).addr;
+  return getSection(Sec).addr;
 }
 
-error_code
-MachOObjectFile::getSectionSize(DataRefImpl Sec, uint64_t &Res) const {
-  if (is64Bit()) {
-    MachO::section_64 Sect = getSection64(Sec);
-    Res = Sect.size;
-  } else {
-    MachO::section Sect = getSection(Sec);
-    Res = Sect.size;
-  }
-
-  return object_error::success;
+uint64_t MachOObjectFile::getSectionSize(DataRefImpl Sec) const {
+  if (is64Bit())
+    return getSection64(Sec).size;
+  return getSection(Sec).size;
 }
 
-error_code
-MachOObjectFile::getSectionContents(DataRefImpl Sec, StringRef &Res) const {
+std::error_code MachOObjectFile::getSectionContents(DataRefImpl Sec,
+                                                    StringRef &Res) const {
   uint32_t Offset;
   uint64_t Size;
 
@@ -706,8 +587,7 @@ MachOObjectFile::getSectionContents(DataRefImpl Sec, StringRef &Res) const {
   return object_error::success;
 }
 
-error_code
-MachOObjectFile::getSectionAlignment(DataRefImpl Sec, uint64_t &Res) const {
+uint64_t MachOObjectFile::getSectionAlignment(DataRefImpl Sec) const {
   uint32_t Align;
   if (is64Bit()) {
     MachO::section_64 Sect = getSection64(Sec);
@@ -717,139 +597,95 @@ MachOObjectFile::getSectionAlignment(DataRefImpl Sec, uint64_t &Res) const {
     Align = Sect.align;
   }
 
-  Res = uint64_t(1) << Align;
-  return object_error::success;
+  return uint64_t(1) << Align;
 }
 
-error_code
-MachOObjectFile::isSectionText(DataRefImpl Sec, bool &Res) const {
+bool MachOObjectFile::isSectionText(DataRefImpl Sec) const {
   uint32_t Flags = getSectionFlags(this, Sec);
-  Res = Flags & MachO::S_ATTR_PURE_INSTRUCTIONS;
-  return object_error::success;
-}
-
-error_code MachOObjectFile::isSectionData(DataRefImpl DRI, bool &Result) const {
-  // FIXME: Unimplemented.
-  Result = false;
-  return object_error::success;
-}
-
-error_code MachOObjectFile::isSectionBSS(DataRefImpl DRI, bool &Result) const {
-  // FIXME: Unimplemented.
-  Result = false;
-  return object_error::success;
+  return Flags & MachO::S_ATTR_PURE_INSTRUCTIONS;
 }
 
-error_code
-MachOObjectFile::isSectionRequiredForExecution(DataRefImpl Sec,
-                                               bool &Result) const {
-  // FIXME: Unimplemented.
-  Result = true;
-  return object_error::success;
-}
-
-error_code MachOObjectFile::isSectionVirtual(DataRefImpl Sec,
-                                             bool &Result) const {
-  // FIXME: Unimplemented.
-  Result = false;
-  return object_error::success;
+bool MachOObjectFile::isSectionData(DataRefImpl Sec) const {
+  uint32_t Flags = getSectionFlags(this, Sec);
+  unsigned SectionType = Flags & MachO::SECTION_TYPE;
+  return !(Flags & MachO::S_ATTR_PURE_INSTRUCTIONS) &&
+         !(SectionType == MachO::S_ZEROFILL ||
+           SectionType == MachO::S_GB_ZEROFILL);
 }
 
-error_code
-MachOObjectFile::isSectionZeroInit(DataRefImpl Sec, bool &Res) const {
+bool MachOObjectFile::isSectionBSS(DataRefImpl Sec) const {
   uint32_t Flags = getSectionFlags(this, Sec);
   unsigned SectionType = Flags & MachO::SECTION_TYPE;
-  Res = SectionType == MachO::S_ZEROFILL ||
-    SectionType == MachO::S_GB_ZEROFILL;
-  return object_error::success;
+  return !(Flags & MachO::S_ATTR_PURE_INSTRUCTIONS) &&
+         (SectionType == MachO::S_ZEROFILL ||
+          SectionType == MachO::S_GB_ZEROFILL);
 }
 
-error_code MachOObjectFile::isSectionReadOnlyData(DataRefImpl Sec,
-                                                  bool &Result) const {
-  // Consider using the code from isSectionText to look for __const sections.
-  // Alternately, emit S_ATTR_PURE_INSTRUCTIONS and/or S_ATTR_SOME_INSTRUCTIONS
-  // to use section attributes to distinguish code from data.
-
+bool MachOObjectFile::isSectionVirtual(DataRefImpl Sec) const {
   // FIXME: Unimplemented.
-  Result = false;
-  return object_error::success;
+  return false;
 }
 
-error_code
-MachOObjectFile::sectionContainsSymbol(DataRefImpl Sec, DataRefImpl Symb,
-                                       bool &Result) const {
+bool MachOObjectFile::sectionContainsSymbol(DataRefImpl Sec,
+                                            DataRefImpl Symb) const {
   SymbolRef::Type ST;
   this->getSymbolType(Symb, ST);
-  if (ST == SymbolRef::ST_Unknown) {
-    Result = false;
-    return object_error::success;
-  }
+  if (ST == SymbolRef::ST_Unknown)
+    return false;
 
-  uint64_t SectBegin, SectEnd;
-  getSectionAddress(Sec, SectBegin);
-  getSectionSize(Sec, SectEnd);
+  uint64_t SectBegin = getSectionAddress(Sec);
+  uint64_t SectEnd = getSectionSize(Sec);
   SectEnd += SectBegin;
 
   uint64_t SymAddr;
   getSymbolAddress(Symb, SymAddr);
-  Result = (SymAddr >= SectBegin) && (SymAddr < SectEnd);
-
-  return object_error::success;
+  return (SymAddr >= SectBegin) && (SymAddr < SectEnd);
 }
 
 relocation_iterator MachOObjectFile::section_rel_begin(DataRefImpl Sec) const {
-  uint32_t Offset;
-  if (is64Bit()) {
-    MachO::section_64 Sect = getSection64(Sec);
-    Offset = Sect.reloff;
-  } else {
-    MachO::section Sect = getSection(Sec);
-    Offset = Sect.reloff;
-  }
-
   DataRefImpl Ret;
-  Ret.p = reinterpret_cast<uintptr_t>(getPtr(this, Offset));
+  Ret.d.a = Sec.d.a;
+  Ret.d.b = 0;
   return relocation_iterator(RelocationRef(Ret, this));
 }
 
 relocation_iterator
 MachOObjectFile::section_rel_end(DataRefImpl Sec) const {
-  uint32_t Offset;
   uint32_t Num;
   if (is64Bit()) {
     MachO::section_64 Sect = getSection64(Sec);
-    Offset = Sect.reloff;
     Num = Sect.nreloc;
   } else {
     MachO::section Sect = getSection(Sec);
-    Offset = Sect.reloff;
     Num = Sect.nreloc;
   }
 
-  const MachO::any_relocation_info *P =
-    reinterpret_cast<const MachO::any_relocation_info *>(getPtr(this, Offset));
-
   DataRefImpl Ret;
-  Ret.p = reinterpret_cast<uintptr_t>(P + Num);
+  Ret.d.a = Sec.d.a;
+  Ret.d.b = Num;
   return relocation_iterator(RelocationRef(Ret, this));
 }
 
-error_code MachOObjectFile::getRelocationNext(DataRefImpl Rel,
-                                              RelocationRef &Res) const {
-  const MachO::any_relocation_info *P =
-    reinterpret_cast<const MachO::any_relocation_info *>(Rel.p);
-  Rel.p = reinterpret_cast<uintptr_t>(P + 1);
-  Res = RelocationRef(Rel, this);
-  return object_error::success;
+void MachOObjectFile::moveRelocationNext(DataRefImpl &Rel) const {
+  ++Rel.d.b;
 }
 
-error_code
-MachOObjectFile::getRelocationAddress(DataRefImpl Rel, uint64_t &Res) const {
-  report_fatal_error("getRelocationAddress not implemented in MachOObjectFile");
+std::error_code MachOObjectFile::getRelocationAddress(DataRefImpl Rel,
+                                                      uint64_t &Res) const {
+  uint64_t Offset;
+  getRelocationOffset(Rel, Offset);
+
+  DataRefImpl Sec;
+  Sec.d.a = Rel.d.a;
+  uint64_t SecAddress = getSectionAddress(Sec);
+  Res = SecAddress + Offset;
+  return object_error::success;
 }
 
-error_code MachOObjectFile::getRelocationOffset(DataRefImpl Rel,
-                                                uint64_t &Res) const {
+std::error_code MachOObjectFile::getRelocationOffset(DataRefImpl Rel,
+                                                     uint64_t &Res) const {
+  assert(getHeader().filetype == MachO::MH_OBJECT &&
+         "Only implemented for MH_OBJECT");
   MachO::any_relocation_info RE = getRelocation(Rel);
   Res = getAnyRelocationAddress(RE);
   return object_error::success;
@@ -858,10 +694,13 @@ error_code MachOObjectFile::getRelocationOffset(DataRefImpl Rel,
 symbol_iterator
 MachOObjectFile::getRelocationSymbol(DataRefImpl Rel) const {
   MachO::any_relocation_info RE = getRelocation(Rel);
+  if (isRelocationScattered(RE))
+    return symbol_end();
+
   uint32_t SymbolIdx = getPlainRelocationSymbolNum(RE);
   bool isExtern = getPlainRelocationExternal(RE);
   if (!isExtern)
-    return end_symbols();
+    return symbol_end();
 
   MachO::symtab_command S = getSymtabLoadCommand();
   unsigned SymbolTableEntrySize = is64Bit() ?
@@ -873,14 +712,19 @@ MachOObjectFile::getRelocationSymbol(DataRefImpl Rel) const {
   return symbol_iterator(SymbolRef(Sym, this));
 }
 
-error_code MachOObjectFile::getRelocationType(DataRefImpl Rel,
-                                              uint64_t &Res) const {
+section_iterator
+MachOObjectFile::getRelocationSection(DataRefImpl Rel) const {
+  return section_iterator(getAnyRelocationSection(getRelocation(Rel)));
+}
+
+std::error_code MachOObjectFile::getRelocationType(DataRefImpl Rel,
+                                                   uint64_t &Res) const {
   MachO::any_relocation_info RE = getRelocation(Rel);
   Res = getAnyRelocationType(RE);
   return object_error::success;
 }
 
-error_code
+std::error_code
 MachOObjectFile::getRelocationTypeName(DataRefImpl Rel,
                                        SmallVectorImpl<char> &Result) const {
   StringRef res;
@@ -943,6 +787,22 @@ MachOObjectFile::getRelocationTypeName(DataRefImpl Rel,
         res = Table[RType];
       break;
     }
+    case Triple::aarch64: {
+      static const char *const Table[] = {
+        "ARM64_RELOC_UNSIGNED",           "ARM64_RELOC_SUBTRACTOR",
+        "ARM64_RELOC_BRANCH26",           "ARM64_RELOC_PAGE21",
+        "ARM64_RELOC_PAGEOFF12",          "ARM64_RELOC_GOT_LOAD_PAGE21",
+        "ARM64_RELOC_GOT_LOAD_PAGEOFF12", "ARM64_RELOC_POINTER_TO_GOT",
+        "ARM64_RELOC_TLVP_LOAD_PAGE21",   "ARM64_RELOC_TLVP_LOAD_PAGEOFF12",
+        "ARM64_RELOC_ADDEND"
+      };
+
+      if (RType >= array_lengthof(Table))
+        res = "Unknown";
+      else
+        res = Table[RType];
+      break;
+    }
     case Triple::ppc: {
       static const char *const Table[] =  {
         "PPC_RELOC_VANILLA",
@@ -976,7 +836,7 @@ MachOObjectFile::getRelocationTypeName(DataRefImpl Rel,
   return object_error::success;
 }
 
-error_code
+std::error_code
 MachOObjectFile::getRelocationValueString(DataRefImpl Rel,
                                           SmallVectorImpl<char> &Result) const {
   MachO::any_relocation_info RE = getRelocation(Rel);
@@ -1005,7 +865,7 @@ MachOObjectFile::getRelocationValueString(DataRefImpl Rel,
       }
       case MachO::X86_64_RELOC_SUBTRACTOR: {
         DataRefImpl RelNext = Rel;
-        RelNext.d.a++;
+        moveRelocationNext(RelNext);
         MachO::any_relocation_info RENext = getRelocation(RelNext);
 
         // X86_64_RELOC_SUBTRACTOR must be followed by a relocation of type
@@ -1053,7 +913,7 @@ MachOObjectFile::getRelocationValueString(DataRefImpl Rel,
         return object_error::success;
       case MachO::GENERIC_RELOC_SECTDIFF: {
         DataRefImpl RelNext = Rel;
-        RelNext.d.a++;
+        moveRelocationNext(RelNext);
         MachO::any_relocation_info RENext = getRelocation(RelNext);
 
         // X86 sect diff's must be followed by a relocation of type
@@ -1075,7 +935,7 @@ MachOObjectFile::getRelocationValueString(DataRefImpl Rel,
       switch (Type) {
         case MachO::GENERIC_RELOC_LOCAL_SECTDIFF: {
           DataRefImpl RelNext = Rel;
-          RelNext.d.a++;
+          moveRelocationNext(RelNext);
           MachO::any_relocation_info RENext = getRelocation(RelNext);
 
           // X86 sect diff's must be followed by a relocation of type
@@ -1114,7 +974,7 @@ MachOObjectFile::getRelocationValueString(DataRefImpl Rel,
           printRelocationTargetName(this, RE, fmt);
 
           DataRefImpl RelNext = Rel;
-          RelNext.d.a++;
+          moveRelocationNext(RelNext);
           MachO::any_relocation_info RENext = getRelocation(RelNext);
 
           // ARM half relocs must be followed by a relocation of type
@@ -1152,8 +1012,8 @@ MachOObjectFile::getRelocationValueString(DataRefImpl Rel,
   return object_error::success;
 }
 
-error_code
-MachOObjectFile::getRelocationHidden(DataRefImpl Rel, bool &Result) const {
+std::error_code MachOObjectFile::getRelocationHidden(DataRefImpl Rel,
+                                                     bool &Result) const {
   unsigned Arch = getArch();
   uint64_t Type;
   getRelocationType(Rel, Type);
@@ -1180,30 +1040,192 @@ MachOObjectFile::getRelocationHidden(DataRefImpl Rel, bool &Result) const {
   return object_error::success;
 }
 
-error_code MachOObjectFile::getLibraryNext(DataRefImpl LibData,
-                                           LibraryRef &Res) const {
-  report_fatal_error("Needed libraries unimplemented in MachOObjectFile");
-}
+//
+// guessLibraryShortName() is passed a name of a dynamic library and returns a
+// guess on what the short name is.  Then name is returned as a substring of the
+// StringRef Name passed in.  The name of the dynamic library is recognized as
+// a framework if it has one of the two following forms:
+//      Foo.framework/Versions/A/Foo
+//      Foo.framework/Foo
+// Where A and Foo can be any string.  And may contain a trailing suffix
+// starting with an underbar.  If the Name is recognized as a framework then
+// isFramework is set to true else it is set to false.  If the Name has a
+// suffix then Suffix is set to the substring in Name that contains the suffix
+// else it is set to a NULL StringRef.
+//
+// The Name of the dynamic library is recognized as a library name if it has
+// one of the two following forms:
+//      libFoo.A.dylib
+//      libFoo.dylib
+// The library may have a suffix trailing the name Foo of the form:
+//      libFoo_profile.A.dylib
+//      libFoo_profile.dylib
+//
+// The Name of the dynamic library is also recognized as a library name if it
+// has the following form:
+//      Foo.qtx
+//
+// If the Name of the dynamic library is none of the forms above then a NULL
+// StringRef is returned.
+//
+StringRef MachOObjectFile::guessLibraryShortName(StringRef Name,
+                                                 bool &isFramework,
+                                                 StringRef &Suffix) {
+  StringRef Foo, F, DotFramework, V, Dylib, Lib, Dot, Qtx;
+  size_t a, b, c, d, Idx;
+
+  isFramework = false;
+  Suffix = StringRef();
+
+  // Pull off the last component and make Foo point to it
+  a = Name.rfind('/');
+  if (a == Name.npos || a == 0)
+    goto guess_library;
+  Foo = Name.slice(a+1, Name.npos);
+
+  // Look for a suffix starting with a '_'
+  Idx = Foo.rfind('_');
+  if (Idx != Foo.npos && Foo.size() >= 2) {
+    Suffix = Foo.slice(Idx, Foo.npos);
+    Foo = Foo.slice(0, Idx);
+  }
+
+  // First look for the form Foo.framework/Foo
+  b = Name.rfind('/', a);
+  if (b == Name.npos)
+    Idx = 0;
+  else
+    Idx = b+1;
+  F = Name.slice(Idx, Idx + Foo.size());
+  DotFramework = Name.slice(Idx + Foo.size(),
+                            Idx + Foo.size() + sizeof(".framework/")-1);
+  if (F == Foo && DotFramework == ".framework/") {
+    isFramework = true;
+    return Foo;
+  }
+
+  // Next look for the form Foo.framework/Versions/A/Foo
+  if (b == Name.npos)
+    goto guess_library;
+  c =  Name.rfind('/', b);
+  if (c == Name.npos || c == 0)
+    goto guess_library;
+  V = Name.slice(c+1, Name.npos);
+  if (!V.startswith("Versions/"))
+    goto guess_library;
+  d =  Name.rfind('/', c);
+  if (d == Name.npos)
+    Idx = 0;
+  else
+    Idx = d+1;
+  F = Name.slice(Idx, Idx + Foo.size());
+  DotFramework = Name.slice(Idx + Foo.size(),
+                            Idx + Foo.size() + sizeof(".framework/")-1);
+  if (F == Foo && DotFramework == ".framework/") {
+    isFramework = true;
+    return Foo;
+  }
+
+guess_library:
+  // pull off the suffix after the "." and make a point to it
+  a = Name.rfind('.');
+  if (a == Name.npos || a == 0)
+    return StringRef();
+  Dylib = Name.slice(a, Name.npos);
+  if (Dylib != ".dylib")
+    goto guess_qtx;
+
+  // First pull off the version letter for the form Foo.A.dylib if any.
+  if (a >= 3) {
+    Dot = Name.slice(a-2, a-1);
+    if (Dot == ".")
+      a = a - 2;
+  }
 
-error_code MachOObjectFile::getLibraryPath(DataRefImpl LibData,
-                                           StringRef &Res) const {
-  report_fatal_error("Needed libraries unimplemented in MachOObjectFile");
+  b = Name.rfind('/', a);
+  if (b == Name.npos)
+    b = 0;
+  else
+    b = b+1;
+  // ignore any suffix after an underbar like Foo_profile.A.dylib
+  Idx = Name.find('_', b);
+  if (Idx != Name.npos && Idx != b) {
+    Lib = Name.slice(b, Idx);
+    Suffix = Name.slice(Idx, a);
+  }
+  else
+    Lib = Name.slice(b, a);
+  // There are incorrect library names of the form:
+  // libATS.A_profile.dylib so check for these.
+  if (Lib.size() >= 3) {
+    Dot = Lib.slice(Lib.size()-2, Lib.size()-1);
+    if (Dot == ".")
+      Lib = Lib.slice(0, Lib.size()-2);
+  }
+  return Lib;
+
+guess_qtx:
+  Qtx = Name.slice(a, Name.npos);
+  if (Qtx != ".qtx")
+    return StringRef();
+  b = Name.rfind('/', a);
+  if (b == Name.npos)
+    Lib = Name.slice(0, a);
+  else
+    Lib = Name.slice(b+1, a);
+  // There are library names of the form: QT.A.qtx so check for these.
+  if (Lib.size() >= 3) {
+    Dot = Lib.slice(Lib.size()-2, Lib.size()-1);
+    if (Dot == ".")
+      Lib = Lib.slice(0, Lib.size()-2);
+  }
+  return Lib;
 }
 
-symbol_iterator MachOObjectFile::begin_symbols() const {
-  DataRefImpl DRI;
-  if (!SymtabLoadCmd)
-    return symbol_iterator(SymbolRef(DRI, this));
+// getLibraryShortNameByIndex() is used to get the short name of the library
+// for an undefined symbol in a linked Mach-O binary that was linked with the
+// normal two-level namespace default (that is MH_TWOLEVEL in the header).
+// It is passed the index (0 - based) of the library as translated from
+// GET_LIBRARY_ORDINAL (1 - based).
+std::error_code MachOObjectFile::getLibraryShortNameByIndex(unsigned Index,
+                                                         StringRef &Res) const {
+  if (Index >= Libraries.size())
+    return object_error::parse_failed;
 
-  MachO::symtab_command Symtab = getSymtabLoadCommand();
-  DRI.p = reinterpret_cast<uintptr_t>(getPtr(this, Symtab.symoff));
-  return symbol_iterator(SymbolRef(DRI, this));
+  // If the cache of LibrariesShortNames is not built up do that first for
+  // all the Libraries.
+  if (LibrariesShortNames.size() == 0) {
+    for (unsigned i = 0; i < Libraries.size(); i++) {
+      MachO::dylib_command D =
+        getStruct<MachO::dylib_command>(this, Libraries[i]);
+      if (D.dylib.name >= D.cmdsize)
+        return object_error::parse_failed;
+      const char *P = (const char *)(Libraries[i]) + D.dylib.name;
+      StringRef Name = StringRef(P);
+      if (D.dylib.name+Name.size() >= D.cmdsize)
+        return object_error::parse_failed;
+      StringRef Suffix;
+      bool isFramework;
+      StringRef shortName = guessLibraryShortName(Name, isFramework, Suffix);
+      if (shortName.empty())
+        LibrariesShortNames.push_back(Name);
+      else
+        LibrariesShortNames.push_back(shortName);
+    }
+  }
+
+  Res = LibrariesShortNames[Index];
+  return object_error::success;
+}
+
+basic_symbol_iterator MachOObjectFile::symbol_begin_impl() const {
+  return getSymbolByIndex(0);
 }
 
-symbol_iterator MachOObjectFile::end_symbols() const {
+basic_symbol_iterator MachOObjectFile::symbol_end_impl() const {
   DataRefImpl DRI;
   if (!SymtabLoadCmd)
-    return symbol_iterator(SymbolRef(DRI, this));
+    return basic_symbol_iterator(SymbolRef(DRI, this));
 
   MachO::symtab_command Symtab = getSymtabLoadCommand();
   unsigned SymbolTableEntrySize = is64Bit() ?
@@ -1212,40 +1234,35 @@ symbol_iterator MachOObjectFile::end_symbols() const {
   unsigned Offset = Symtab.symoff +
     Symtab.nsyms * SymbolTableEntrySize;
   DRI.p = reinterpret_cast<uintptr_t>(getPtr(this, Offset));
-  return symbol_iterator(SymbolRef(DRI, this));
+  return basic_symbol_iterator(SymbolRef(DRI, this));
 }
 
-symbol_iterator MachOObjectFile::begin_dynamic_symbols() const {
-  // TODO: implement
-  report_fatal_error("Dynamic symbols unimplemented in MachOObjectFile");
-}
+basic_symbol_iterator MachOObjectFile::getSymbolByIndex(unsigned Index) const {
+  DataRefImpl DRI;
+  if (!SymtabLoadCmd)
+    return basic_symbol_iterator(SymbolRef(DRI, this));
 
-symbol_iterator MachOObjectFile::end_dynamic_symbols() const {
-  // TODO: implement
-  report_fatal_error("Dynamic symbols unimplemented in MachOObjectFile");
+  MachO::symtab_command Symtab = getSymtabLoadCommand();
+  if (Index >= Symtab.nsyms)
+    report_fatal_error("Requested symbol index is out of range.");
+  unsigned SymbolTableEntrySize =
+    is64Bit() ? sizeof(MachO::nlist_64) : sizeof(MachO::nlist);
+  DRI.p = reinterpret_cast<uintptr_t>(getPtr(this, Symtab.symoff));
+  DRI.p += Index * SymbolTableEntrySize;
+  return basic_symbol_iterator(SymbolRef(DRI, this));
 }
 
-section_iterator MachOObjectFile::begin_sections() const {
+section_iterator MachOObjectFile::section_begin() const {
   DataRefImpl DRI;
   return section_iterator(SectionRef(DRI, this));
 }
 
-section_iterator MachOObjectFile::end_sections() const {
+section_iterator MachOObjectFile::section_end() const {
   DataRefImpl DRI;
   DRI.d.a = Sections.size();
   return section_iterator(SectionRef(DRI, this));
 }
 
-library_iterator MachOObjectFile::begin_libraries_needed() const {
-  // TODO: implement
-  report_fatal_error("Needed libraries unimplemented in MachOObjectFile");
-}
-
-library_iterator MachOObjectFile::end_libraries_needed() const {
-  // TODO: implement
-  report_fatal_error("Needed libraries unimplemented in MachOObjectFile");
-}
-
 uint8_t MachOObjectFile::getBytesInAddress() const {
   return is64Bit() ? 8 : 4;
 }
@@ -1261,20 +1278,15 @@ StringRef MachOObjectFile::getFileFormatName() const {
     case llvm::MachO::CPU_TYPE_POWERPC:
       return "Mach-O 32-bit ppc";
     default:
-      assert((CPUType & llvm::MachO::CPU_ARCH_ABI64) == 0 &&
-             "64-bit object file when we're not 64-bit?");
       return "Mach-O 32-bit unknown";
     }
   }
 
-  // Make sure the cpu type has the correct mask.
-  assert((CPUType & llvm::MachO::CPU_ARCH_ABI64)
-         == llvm::MachO::CPU_ARCH_ABI64 &&
-         "32-bit object file when we're 64-bit?");
-
   switch (CPUType) {
   case llvm::MachO::CPU_TYPE_X86_64:
     return "Mach-O 64-bit x86-64";
+  case llvm::MachO::CPU_TYPE_ARM64:
+    return "Mach-O arm64";
   case llvm::MachO::CPU_TYPE_POWERPC64:
     return "Mach-O 64-bit ppc64";
   default:
@@ -1290,6 +1302,8 @@ Triple::ArchType MachOObjectFile::getArch(uint32_t CPUType) {
     return Triple::x86_64;
   case llvm::MachO::CPU_TYPE_ARM:
     return Triple::arm;
+  case llvm::MachO::CPU_TYPE_ARM64:
+    return Triple::aarch64;
   case llvm::MachO::CPU_TYPE_POWERPC:
     return Triple::ppc;
   case llvm::MachO::CPU_TYPE_POWERPC64:
@@ -1299,13 +1313,181 @@ Triple::ArchType MachOObjectFile::getArch(uint32_t CPUType) {
   }
 }
 
+Triple MachOObjectFile::getArch(uint32_t CPUType, uint32_t CPUSubType,
+                                const char **McpuDefault) {
+  if (McpuDefault)
+    *McpuDefault = nullptr;
+
+  switch (CPUType) {
+  case MachO::CPU_TYPE_I386:
+    switch (CPUSubType & ~MachO::CPU_SUBTYPE_MASK) {
+    case MachO::CPU_SUBTYPE_I386_ALL:
+      return Triple("i386-apple-darwin");
+    default:
+      return Triple();
+    }
+  case MachO::CPU_TYPE_X86_64:
+    switch (CPUSubType & ~MachO::CPU_SUBTYPE_MASK) {
+    case MachO::CPU_SUBTYPE_X86_64_ALL:
+      return Triple("x86_64-apple-darwin");
+    case MachO::CPU_SUBTYPE_X86_64_H:
+      return Triple("x86_64h-apple-darwin");
+    default:
+      return Triple();
+    }
+  case MachO::CPU_TYPE_ARM:
+    switch (CPUSubType & ~MachO::CPU_SUBTYPE_MASK) {
+    case MachO::CPU_SUBTYPE_ARM_V4T:
+      return Triple("armv4t-apple-darwin");
+    case MachO::CPU_SUBTYPE_ARM_V5TEJ:
+      return Triple("armv5e-apple-darwin");
+    case MachO::CPU_SUBTYPE_ARM_XSCALE:
+      return Triple("xscale-apple-darwin");
+    case MachO::CPU_SUBTYPE_ARM_V6:
+      return Triple("armv6-apple-darwin");
+    case MachO::CPU_SUBTYPE_ARM_V6M:
+      if (McpuDefault)
+        *McpuDefault = "cortex-m0";
+      return Triple("armv6m-apple-darwin");
+    case MachO::CPU_SUBTYPE_ARM_V7:
+      return Triple("armv7-apple-darwin");
+    case MachO::CPU_SUBTYPE_ARM_V7EM:
+      if (McpuDefault)
+        *McpuDefault = "cortex-m4";
+      return Triple("armv7em-apple-darwin");
+    case MachO::CPU_SUBTYPE_ARM_V7K:
+      return Triple("armv7k-apple-darwin");
+    case MachO::CPU_SUBTYPE_ARM_V7M:
+      if (McpuDefault)
+        *McpuDefault = "cortex-m3";
+      return Triple("armv7m-apple-darwin");
+    case MachO::CPU_SUBTYPE_ARM_V7S:
+      return Triple("armv7s-apple-darwin");
+    default:
+      return Triple();
+    }
+  case MachO::CPU_TYPE_ARM64:
+    switch (CPUSubType & ~MachO::CPU_SUBTYPE_MASK) {
+    case MachO::CPU_SUBTYPE_ARM64_ALL:
+      return Triple("arm64-apple-darwin");
+    default:
+      return Triple();
+    }
+  case MachO::CPU_TYPE_POWERPC:
+    switch (CPUSubType & ~MachO::CPU_SUBTYPE_MASK) {
+    case MachO::CPU_SUBTYPE_POWERPC_ALL:
+      return Triple("ppc-apple-darwin");
+    default:
+      return Triple();
+    }
+  case MachO::CPU_TYPE_POWERPC64:
+    switch (CPUSubType & ~MachO::CPU_SUBTYPE_MASK) {
+    case MachO::CPU_SUBTYPE_POWERPC_ALL:
+      return Triple("ppc64-apple-darwin");
+    default:
+      return Triple();
+    }
+  default:
+    return Triple();
+  }
+}
+
+Triple MachOObjectFile::getThumbArch(uint32_t CPUType, uint32_t CPUSubType,
+                                     const char **McpuDefault) {
+  if (McpuDefault)
+    *McpuDefault = nullptr;
+
+  switch (CPUType) {
+  case MachO::CPU_TYPE_ARM:
+    switch (CPUSubType & ~MachO::CPU_SUBTYPE_MASK) {
+    case MachO::CPU_SUBTYPE_ARM_V4T:
+      return Triple("thumbv4t-apple-darwin");
+    case MachO::CPU_SUBTYPE_ARM_V5TEJ:
+      return Triple("thumbv5e-apple-darwin");
+    case MachO::CPU_SUBTYPE_ARM_XSCALE:
+      return Triple("xscale-apple-darwin");
+    case MachO::CPU_SUBTYPE_ARM_V6:
+      return Triple("thumbv6-apple-darwin");
+    case MachO::CPU_SUBTYPE_ARM_V6M:
+      if (McpuDefault)
+        *McpuDefault = "cortex-m0";
+      return Triple("thumbv6m-apple-darwin");
+    case MachO::CPU_SUBTYPE_ARM_V7:
+      return Triple("thumbv7-apple-darwin");
+    case MachO::CPU_SUBTYPE_ARM_V7EM:
+      if (McpuDefault)
+        *McpuDefault = "cortex-m4";
+      return Triple("thumbv7em-apple-darwin");
+    case MachO::CPU_SUBTYPE_ARM_V7K:
+      return Triple("thumbv7k-apple-darwin");
+    case MachO::CPU_SUBTYPE_ARM_V7M:
+      if (McpuDefault)
+        *McpuDefault = "cortex-m3";
+      return Triple("thumbv7m-apple-darwin");
+    case MachO::CPU_SUBTYPE_ARM_V7S:
+      return Triple("thumbv7s-apple-darwin");
+    default:
+      return Triple();
+    }
+  default:
+    return Triple();
+  }
+}
+
+Triple MachOObjectFile::getArch(uint32_t CPUType, uint32_t CPUSubType,
+                                const char **McpuDefault,
+                               Triple *ThumbTriple) {
+  Triple T = MachOObjectFile::getArch(CPUType, CPUSubType, McpuDefault);
+  *ThumbTriple = MachOObjectFile::getThumbArch(CPUType, CPUSubType,
+                                               McpuDefault);
+  return T;
+}
+
+Triple MachOObjectFile::getHostArch() {
+  return Triple(sys::getDefaultTargetTriple());
+}
+
+bool MachOObjectFile::isValidArch(StringRef ArchFlag) {
+  return StringSwitch<bool>(ArchFlag)
+      .Case("i386", true)
+      .Case("x86_64", true)
+      .Case("x86_64h", true)
+      .Case("armv4t", true)
+      .Case("arm", true)
+      .Case("armv5e", true)
+      .Case("armv6", true)
+      .Case("armv6m", true)
+      .Case("armv7em", true)
+      .Case("armv7k", true)
+      .Case("armv7m", true)
+      .Case("armv7s", true)
+      .Case("arm64", true)
+      .Case("ppc", true)
+      .Case("ppc64", true)
+      .Default(false);
+}
+
 unsigned MachOObjectFile::getArch() const {
   return getArch(getCPUType(this));
 }
 
-StringRef MachOObjectFile::getLoadName() const {
-  // TODO: Implement
-  report_fatal_error("get_load_name() unimplemented in MachOObjectFile");
+Triple MachOObjectFile::getArch(const char **McpuDefault,
+                                Triple *ThumbTriple) const {
+  Triple T;
+  if (is64Bit()) {
+    MachO::mach_header_64 H_64;
+    H_64 = getHeader64();
+    T = MachOObjectFile::getArch(H_64.cputype, H_64.cpusubtype, McpuDefault);
+    *ThumbTriple = MachOObjectFile::getThumbArch(H_64.cputype, H_64.cpusubtype,
+                                                 McpuDefault);
+  } else {
+    MachO::mach_header H;
+    H = getHeader();
+    T = MachOObjectFile::getArch(H.cputype, H.cpusubtype, McpuDefault);
+    *ThumbTriple = MachOObjectFile::getThumbArch(H.cputype, H.cpusubtype,
+                                                 McpuDefault);
+  }
+  return T;
 }
 
 relocation_iterator MachOObjectFile::section_rel_begin(unsigned Index) const {
@@ -1341,6 +1523,623 @@ dice_iterator MachOObjectFile::end_dices() const {
   return dice_iterator(DiceRef(DRI, this));
 }
 
+ExportEntry::ExportEntry(ArrayRef<uint8_t> T) 
+  : Trie(T), Malformed(false), Done(false) { }
+
+void ExportEntry::moveToFirst() {
+  pushNode(0);
+  pushDownUntilBottom();
+}
+
+void ExportEntry::moveToEnd() {
+  Stack.clear();
+  Done = true;
+}
+
+bool ExportEntry::operator==(const ExportEntry &Other) const {
+  // Common case, one at end, other iterating from begin. 
+  if (Done || Other.Done)
+    return (Done == Other.Done);
+  // Not equal if different stack sizes.
+  if (Stack.size() != Other.Stack.size())
+    return false;
+  // Not equal if different cumulative strings.
+  if (!CumulativeString.equals(Other.CumulativeString))
+    return false;
+  // Equal if all nodes in both stacks match.
+  for (unsigned i=0; i < Stack.size(); ++i) {
+    if (Stack[i].Start != Other.Stack[i].Start)
+      return false;
+  }
+  return true;  
+}
+
+uint64_t ExportEntry::readULEB128(const uint8_t *&Ptr) {
+  unsigned Count;
+  uint64_t Result = decodeULEB128(Ptr, &Count);
+  Ptr += Count;
+  if (Ptr > Trie.end()) {
+    Ptr = Trie.end();
+    Malformed = true;
+  }
+  return Result;
+}
+
+StringRef ExportEntry::name() const {
+  return CumulativeString;
+}
+
+uint64_t ExportEntry::flags() const {
+  return Stack.back().Flags;
+}
+
+uint64_t ExportEntry::address() const {
+  return Stack.back().Address;
+}
+
+uint64_t ExportEntry::other() const {
+  return Stack.back().Other;
+}
+
+StringRef ExportEntry::otherName() const {
+  const char* ImportName = Stack.back().ImportName;
+  if (ImportName)
+    return StringRef(ImportName);
+  return StringRef();
+}
+
+uint32_t ExportEntry::nodeOffset() const {
+  return Stack.back().Start - Trie.begin();
+}
+
+ExportEntry::NodeState::NodeState(const uint8_t *Ptr) 
+  : Start(Ptr), Current(Ptr), Flags(0), Address(0), Other(0), 
+    ImportName(nullptr), ChildCount(0), NextChildIndex(0),  
+    ParentStringLength(0), IsExportNode(false) {
+}
+
+void ExportEntry::pushNode(uint64_t offset) {
+  const uint8_t *Ptr = Trie.begin() + offset;
+  NodeState State(Ptr);
+  uint64_t ExportInfoSize = readULEB128(State.Current);
+  State.IsExportNode = (ExportInfoSize != 0);
+  const uint8_t* Children = State.Current + ExportInfoSize;
+  if (State.IsExportNode) {
+    State.Flags = readULEB128(State.Current);
+    if (State.Flags & MachO::EXPORT_SYMBOL_FLAGS_REEXPORT) {
+      State.Address = 0;
+      State.Other = readULEB128(State.Current); // dylib ordinal
+      State.ImportName = reinterpret_cast<const char*>(State.Current);
+    } else {
+      State.Address = readULEB128(State.Current);
+      if (State.Flags & MachO::EXPORT_SYMBOL_FLAGS_STUB_AND_RESOLVER)
+        State.Other = readULEB128(State.Current); 
+    }
+  }
+  State.ChildCount = *Children;
+  State.Current = Children + 1;
+  State.NextChildIndex = 0;
+  State.ParentStringLength = CumulativeString.size();
+  Stack.push_back(State);
+}
+
+void ExportEntry::pushDownUntilBottom() {
+  while (Stack.back().NextChildIndex < Stack.back().ChildCount) {
+    NodeState &Top = Stack.back();
+    CumulativeString.resize(Top.ParentStringLength);
+    for (;*Top.Current != 0; Top.Current++) {
+      char C = *Top.Current;
+      CumulativeString.push_back(C);
+    }
+    Top.Current += 1;
+    uint64_t childNodeIndex = readULEB128(Top.Current);
+    Top.NextChildIndex += 1;
+    pushNode(childNodeIndex);
+  }
+  if (!Stack.back().IsExportNode) {
+    Malformed = true;
+    moveToEnd();
+  }
+}
+
+// We have a trie data structure and need a way to walk it that is compatible
+// with the C++ iterator model. The solution is a non-recursive depth first
+// traversal where the iterator contains a stack of parent nodes along with a
+// string that is the accumulation of all edge strings along the parent chain
+// to this point.
+//
+// There is one "export" node for each exported symbol.  But because some
+// symbols may be a prefix of another symbol (e.g. _dup and _dup2), an export
+// node may have child nodes too.  
+//
+// The algorithm for moveNext() is to keep moving down the leftmost unvisited
+// child until hitting a node with no children (which is an export node or
+// else the trie is malformed). On the way down, each node is pushed on the
+// stack ivar.  If there is no more ways down, it pops up one and tries to go
+// down a sibling path until a childless node is reached.
+void ExportEntry::moveNext() {
+  if (Stack.empty() || !Stack.back().IsExportNode) {
+    Malformed = true;
+    moveToEnd();
+    return;
+  }
+
+  Stack.pop_back();
+  while (!Stack.empty()) {
+    NodeState &Top = Stack.back();
+    if (Top.NextChildIndex < Top.ChildCount) {
+      pushDownUntilBottom();
+      // Now at the next export node.
+      return;
+    } else {
+      if (Top.IsExportNode) {
+        // This node has no children but is itself an export node.
+        CumulativeString.resize(Top.ParentStringLength);
+        return;
+      }
+      Stack.pop_back();
+    }
+  }
+  Done = true;
+}
+
+iterator_range<export_iterator> 
+MachOObjectFile::exports(ArrayRef<uint8_t> Trie) {
+  ExportEntry Start(Trie);
+  if (Trie.size() == 0)
+    Start.moveToEnd();
+  else
+    Start.moveToFirst();
+
+  ExportEntry Finish(Trie);
+  Finish.moveToEnd();
+
+  return iterator_range<export_iterator>(export_iterator(Start), 
+                                         export_iterator(Finish));
+}
+
+iterator_range<export_iterator> MachOObjectFile::exports() const {
+  return exports(getDyldInfoExportsTrie());
+}
+
+
+MachORebaseEntry::MachORebaseEntry(ArrayRef<uint8_t> Bytes, bool is64Bit)
+    : Opcodes(Bytes), Ptr(Bytes.begin()), SegmentOffset(0), SegmentIndex(0),
+      RemainingLoopCount(0), AdvanceAmount(0), RebaseType(0),
+      PointerSize(is64Bit ? 8 : 4), Malformed(false), Done(false) {}
+
+void MachORebaseEntry::moveToFirst() {
+  Ptr = Opcodes.begin();
+  moveNext();
+}
+
+void MachORebaseEntry::moveToEnd() {
+  Ptr = Opcodes.end();
+  RemainingLoopCount = 0;
+  Done = true;
+}
+
+void MachORebaseEntry::moveNext() {
+  // If in the middle of some loop, move to next rebasing in loop.
+  SegmentOffset += AdvanceAmount;
+  if (RemainingLoopCount) {
+    --RemainingLoopCount;
+    return;
+  }
+  if (Ptr == Opcodes.end()) {
+    Done = true;
+    return;
+  }
+  bool More = true;
+  while (More && !Malformed) {
+    // Parse next opcode and set up next loop.
+    uint8_t Byte = *Ptr++;
+    uint8_t ImmValue = Byte & MachO::REBASE_IMMEDIATE_MASK;
+    uint8_t Opcode = Byte & MachO::REBASE_OPCODE_MASK;
+    switch (Opcode) {
+    case MachO::REBASE_OPCODE_DONE:
+      More = false;
+      Done = true;
+      moveToEnd();
+      DEBUG_WITH_TYPE("mach-o-rebase", llvm::dbgs() << "REBASE_OPCODE_DONE\n");
+      break;
+    case MachO::REBASE_OPCODE_SET_TYPE_IMM:
+      RebaseType = ImmValue;
+      DEBUG_WITH_TYPE(
+          "mach-o-rebase",
+          llvm::dbgs() << "REBASE_OPCODE_SET_TYPE_IMM: "
+                       << "RebaseType=" << (int) RebaseType << "\n");
+      break;
+    case MachO::REBASE_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB:
+      SegmentIndex = ImmValue;
+      SegmentOffset = readULEB128();
+      DEBUG_WITH_TYPE(
+          "mach-o-rebase",
+          llvm::dbgs() << "REBASE_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB: "
+                       << "SegmentIndex=" << SegmentIndex << ", "
+                       << format("SegmentOffset=0x%06X", SegmentOffset)
+                       << "\n");
+      break;
+    case MachO::REBASE_OPCODE_ADD_ADDR_ULEB:
+      SegmentOffset += readULEB128();
+      DEBUG_WITH_TYPE("mach-o-rebase",
+                      llvm::dbgs() << "REBASE_OPCODE_ADD_ADDR_ULEB: "
+                                   << format("SegmentOffset=0x%06X",
+                                             SegmentOffset) << "\n");
+      break;
+    case MachO::REBASE_OPCODE_ADD_ADDR_IMM_SCALED:
+      SegmentOffset += ImmValue * PointerSize;
+      DEBUG_WITH_TYPE("mach-o-rebase",
+                      llvm::dbgs() << "REBASE_OPCODE_ADD_ADDR_IMM_SCALED: "
+                                   << format("SegmentOffset=0x%06X",
+                                             SegmentOffset) << "\n");
+      break;
+    case MachO::REBASE_OPCODE_DO_REBASE_IMM_TIMES:
+      AdvanceAmount = PointerSize;
+      RemainingLoopCount = ImmValue - 1;
+      DEBUG_WITH_TYPE(
+          "mach-o-rebase",
+          llvm::dbgs() << "REBASE_OPCODE_DO_REBASE_IMM_TIMES: "
+                       << format("SegmentOffset=0x%06X", SegmentOffset)
+                       << ", AdvanceAmount=" << AdvanceAmount
+                       << ", RemainingLoopCount=" << RemainingLoopCount
+                       << "\n");
+      return;
+    case MachO::REBASE_OPCODE_DO_REBASE_ULEB_TIMES:
+      AdvanceAmount = PointerSize;
+      RemainingLoopCount = readULEB128() - 1;
+      DEBUG_WITH_TYPE(
+          "mach-o-rebase",
+          llvm::dbgs() << "REBASE_OPCODE_DO_REBASE_ULEB_TIMES: "
+                       << format("SegmentOffset=0x%06X", SegmentOffset)
+                       << ", AdvanceAmount=" << AdvanceAmount
+                       << ", RemainingLoopCount=" << RemainingLoopCount
+                       << "\n");
+      return;
+    case MachO::REBASE_OPCODE_DO_REBASE_ADD_ADDR_ULEB:
+      AdvanceAmount = readULEB128() + PointerSize;
+      RemainingLoopCount = 0;
+      DEBUG_WITH_TYPE(
+          "mach-o-rebase",
+          llvm::dbgs() << "REBASE_OPCODE_DO_REBASE_ADD_ADDR_ULEB: "
+                       << format("SegmentOffset=0x%06X", SegmentOffset)
+                       << ", AdvanceAmount=" << AdvanceAmount
+                       << ", RemainingLoopCount=" << RemainingLoopCount
+                       << "\n");
+      return;
+    case MachO::REBASE_OPCODE_DO_REBASE_ULEB_TIMES_SKIPPING_ULEB:
+      RemainingLoopCount = readULEB128() - 1;
+      AdvanceAmount = readULEB128() + PointerSize;
+      DEBUG_WITH_TYPE(
+          "mach-o-rebase",
+          llvm::dbgs() << "REBASE_OPCODE_DO_REBASE_ULEB_TIMES_SKIPPING_ULEB: "
+                       << format("SegmentOffset=0x%06X", SegmentOffset)
+                       << ", AdvanceAmount=" << AdvanceAmount
+                       << ", RemainingLoopCount=" << RemainingLoopCount
+                       << "\n");
+      return;
+    default:
+      Malformed = true;
+    }
+  }
+}
+
+uint64_t MachORebaseEntry::readULEB128() {
+  unsigned Count;
+  uint64_t Result = decodeULEB128(Ptr, &Count);
+  Ptr += Count;
+  if (Ptr > Opcodes.end()) {
+    Ptr = Opcodes.end();
+    Malformed = true;
+  }
+  return Result;
+}
+
+uint32_t MachORebaseEntry::segmentIndex() const { return SegmentIndex; }
+
+uint64_t MachORebaseEntry::segmentOffset() const { return SegmentOffset; }
+
+StringRef MachORebaseEntry::typeName() const {
+  switch (RebaseType) {
+  case MachO::REBASE_TYPE_POINTER:
+    return "pointer";
+  case MachO::REBASE_TYPE_TEXT_ABSOLUTE32:
+    return "text abs32";
+  case MachO::REBASE_TYPE_TEXT_PCREL32:
+    return "text rel32";
+  }
+  return "unknown";
+}
+
+bool MachORebaseEntry::operator==(const MachORebaseEntry &Other) const {
+  assert(Opcodes == Other.Opcodes && "compare iterators of different files");
+  return (Ptr == Other.Ptr) &&
+         (RemainingLoopCount == Other.RemainingLoopCount) &&
+         (Done == Other.Done);
+}
+
+iterator_range<rebase_iterator>
+MachOObjectFile::rebaseTable(ArrayRef<uint8_t> Opcodes, bool is64) {
+  MachORebaseEntry Start(Opcodes, is64);
+  Start.moveToFirst();
+
+  MachORebaseEntry Finish(Opcodes, is64);
+  Finish.moveToEnd();
+
+  return iterator_range<rebase_iterator>(rebase_iterator(Start),
+                                         rebase_iterator(Finish));
+}
+
+iterator_range<rebase_iterator> MachOObjectFile::rebaseTable() const {
+  return rebaseTable(getDyldInfoRebaseOpcodes(), is64Bit());
+}
+
+
+MachOBindEntry::MachOBindEntry(ArrayRef<uint8_t> Bytes, bool is64Bit,
+                               Kind BK)
+    : Opcodes(Bytes), Ptr(Bytes.begin()), SegmentOffset(0), SegmentIndex(0),
+      Ordinal(0), Flags(0), Addend(0), RemainingLoopCount(0), AdvanceAmount(0),
+      BindType(0), PointerSize(is64Bit ? 8 : 4),
+      TableKind(BK), Malformed(false), Done(false) {}
+
+void MachOBindEntry::moveToFirst() {
+  Ptr = Opcodes.begin();
+  moveNext();
+}
+
+void MachOBindEntry::moveToEnd() {
+  Ptr = Opcodes.end();
+  RemainingLoopCount = 0;
+  Done = true;
+}
+
+void MachOBindEntry::moveNext() {
+  // If in the middle of some loop, move to next binding in loop.
+  SegmentOffset += AdvanceAmount;
+  if (RemainingLoopCount) {
+    --RemainingLoopCount;
+    return;
+  }
+  if (Ptr == Opcodes.end()) {
+    Done = true;
+    return;
+  }
+  bool More = true;
+  while (More && !Malformed) {
+    // Parse next opcode and set up next loop.
+    uint8_t Byte = *Ptr++;
+    uint8_t ImmValue = Byte & MachO::BIND_IMMEDIATE_MASK;
+    uint8_t Opcode = Byte & MachO::BIND_OPCODE_MASK;
+    int8_t SignExtended;
+    const uint8_t *SymStart;
+    switch (Opcode) {
+    case MachO::BIND_OPCODE_DONE:
+      if (TableKind == Kind::Lazy) {
+        // Lazying bindings have a DONE opcode between entries.  Need to ignore
+        // it to advance to next entry.  But need not if this is last entry.
+        bool NotLastEntry = false;
+        for (const uint8_t *P = Ptr; P < Opcodes.end(); ++P) {
+          if (*P) {
+            NotLastEntry = true;
+          }
+        }
+        if (NotLastEntry)
+          break;
+      }
+      More = false;
+      Done = true;
+      moveToEnd();
+      DEBUG_WITH_TYPE("mach-o-bind", llvm::dbgs() << "BIND_OPCODE_DONE\n");
+      break;
+    case MachO::BIND_OPCODE_SET_DYLIB_ORDINAL_IMM:
+      Ordinal = ImmValue;
+      DEBUG_WITH_TYPE(
+          "mach-o-bind",
+          llvm::dbgs() << "BIND_OPCODE_SET_DYLIB_ORDINAL_IMM: "
+                       << "Ordinal=" << Ordinal << "\n");
+      break;
+    case MachO::BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB:
+      Ordinal = readULEB128();
+      DEBUG_WITH_TYPE(
+          "mach-o-bind",
+          llvm::dbgs() << "BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB: "
+                       << "Ordinal=" << Ordinal << "\n");
+      break;
+    case MachO::BIND_OPCODE_SET_DYLIB_SPECIAL_IMM:
+      if (ImmValue) {
+        SignExtended = MachO::BIND_OPCODE_MASK | ImmValue;
+        Ordinal = SignExtended;
+      } else
+        Ordinal = 0;
+      DEBUG_WITH_TYPE(
+          "mach-o-bind",
+          llvm::dbgs() << "BIND_OPCODE_SET_DYLIB_SPECIAL_IMM: "
+                       << "Ordinal=" << Ordinal << "\n");
+      break;
+    case MachO::BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM:
+      Flags = ImmValue;
+      SymStart = Ptr;
+      while (*Ptr) {
+        ++Ptr;
+      }
+      SymbolName = StringRef(reinterpret_cast<const char*>(SymStart),
+                             Ptr-SymStart);
+      ++Ptr;
+      DEBUG_WITH_TYPE(
+          "mach-o-bind",
+          llvm::dbgs() << "BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM: "
+                       << "SymbolName=" << SymbolName << "\n");
+      if (TableKind == Kind::Weak) {
+        if (ImmValue & MachO::BIND_SYMBOL_FLAGS_NON_WEAK_DEFINITION)
+          return;
+      }
+      break;
+    case MachO::BIND_OPCODE_SET_TYPE_IMM:
+      BindType = ImmValue;
+      DEBUG_WITH_TYPE(
+          "mach-o-bind",
+          llvm::dbgs() << "BIND_OPCODE_SET_TYPE_IMM: "
+                       << "BindType=" << (int)BindType << "\n");
+      break;
+    case MachO::BIND_OPCODE_SET_ADDEND_SLEB:
+      Addend = readSLEB128();
+      if (TableKind == Kind::Lazy)
+        Malformed = true;
+      DEBUG_WITH_TYPE(
+          "mach-o-bind",
+          llvm::dbgs() << "BIND_OPCODE_SET_ADDEND_SLEB: "
+                       << "Addend=" << Addend << "\n");
+      break;
+    case MachO::BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB:
+      SegmentIndex = ImmValue;
+      SegmentOffset = readULEB128();
+      DEBUG_WITH_TYPE(
+          "mach-o-bind",
+          llvm::dbgs() << "BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB: "
+                       << "SegmentIndex=" << SegmentIndex << ", "
+                       << format("SegmentOffset=0x%06X", SegmentOffset)
+                       << "\n");
+      break;
+    case MachO::BIND_OPCODE_ADD_ADDR_ULEB:
+      SegmentOffset += readULEB128();
+      DEBUG_WITH_TYPE("mach-o-bind",
+                      llvm::dbgs() << "BIND_OPCODE_ADD_ADDR_ULEB: "
+                                   << format("SegmentOffset=0x%06X",
+                                             SegmentOffset) << "\n");
+      break;
+    case MachO::BIND_OPCODE_DO_BIND:
+      AdvanceAmount = PointerSize;
+      RemainingLoopCount = 0;
+      DEBUG_WITH_TYPE("mach-o-bind",
+                      llvm::dbgs() << "BIND_OPCODE_DO_BIND: "
+                                   << format("SegmentOffset=0x%06X",
+                                             SegmentOffset) << "\n");
+      return;
+     case MachO::BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB:
+      AdvanceAmount = readULEB128() + PointerSize;
+      RemainingLoopCount = 0;
+      if (TableKind == Kind::Lazy)
+        Malformed = true;
+      DEBUG_WITH_TYPE(
+          "mach-o-bind",
+          llvm::dbgs() << "BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB: "
+                       << format("SegmentOffset=0x%06X", SegmentOffset)
+                       << ", AdvanceAmount=" << AdvanceAmount
+                       << ", RemainingLoopCount=" << RemainingLoopCount
+                       << "\n");
+      return;
+    case MachO::BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED:
+      AdvanceAmount = ImmValue * PointerSize + PointerSize;
+      RemainingLoopCount = 0;
+      if (TableKind == Kind::Lazy)
+        Malformed = true;
+      DEBUG_WITH_TYPE("mach-o-bind",
+                      llvm::dbgs()
+                      << "BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED: "
+                      << format("SegmentOffset=0x%06X",
+                                             SegmentOffset) << "\n");
+      return;
+    case MachO::BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB:
+      RemainingLoopCount = readULEB128() - 1;
+      AdvanceAmount = readULEB128() + PointerSize;
+      if (TableKind == Kind::Lazy)
+        Malformed = true;
+      DEBUG_WITH_TYPE(
+          "mach-o-bind",
+          llvm::dbgs() << "BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB: "
+                       << format("SegmentOffset=0x%06X", SegmentOffset)
+                       << ", AdvanceAmount=" << AdvanceAmount
+                       << ", RemainingLoopCount=" << RemainingLoopCount
+                       << "\n");
+      return;
+    default:
+      Malformed = true;
+    }
+  }
+}
+
+uint64_t MachOBindEntry::readULEB128() {
+  unsigned Count;
+  uint64_t Result = decodeULEB128(Ptr, &Count);
+  Ptr += Count;
+  if (Ptr > Opcodes.end()) {
+    Ptr = Opcodes.end();
+    Malformed = true;
+  }
+  return Result;
+}
+
+int64_t MachOBindEntry::readSLEB128() {
+  unsigned Count;
+  int64_t Result = decodeSLEB128(Ptr, &Count);
+  Ptr += Count;
+  if (Ptr > Opcodes.end()) {
+    Ptr = Opcodes.end();
+    Malformed = true;
+  }
+  return Result;
+}
+
+
+uint32_t MachOBindEntry::segmentIndex() const { return SegmentIndex; }
+
+uint64_t MachOBindEntry::segmentOffset() const { return SegmentOffset; }
+
+StringRef MachOBindEntry::typeName() const {
+  switch (BindType) {
+  case MachO::BIND_TYPE_POINTER:
+    return "pointer";
+  case MachO::BIND_TYPE_TEXT_ABSOLUTE32:
+    return "text abs32";
+  case MachO::BIND_TYPE_TEXT_PCREL32:
+    return "text rel32";
+  }
+  return "unknown";
+}
+
+StringRef MachOBindEntry::symbolName() const { return SymbolName; }
+
+int64_t MachOBindEntry::addend() const { return Addend; }
+
+uint32_t MachOBindEntry::flags() const { return Flags; }
+
+int MachOBindEntry::ordinal() const { return Ordinal; }
+
+bool MachOBindEntry::operator==(const MachOBindEntry &Other) const {
+  assert(Opcodes == Other.Opcodes && "compare iterators of different files");
+  return (Ptr == Other.Ptr) &&
+         (RemainingLoopCount == Other.RemainingLoopCount) &&
+         (Done == Other.Done);
+}
+
+iterator_range<bind_iterator>
+MachOObjectFile::bindTable(ArrayRef<uint8_t> Opcodes, bool is64,
+                           MachOBindEntry::Kind BKind) {
+  MachOBindEntry Start(Opcodes, is64, BKind);
+  Start.moveToFirst();
+
+  MachOBindEntry Finish(Opcodes, is64, BKind);
+  Finish.moveToEnd();
+
+  return iterator_range<bind_iterator>(bind_iterator(Start),
+                                       bind_iterator(Finish));
+}
+
+iterator_range<bind_iterator> MachOObjectFile::bindTable() const {
+  return bindTable(getDyldInfoBindOpcodes(), is64Bit(),
+                   MachOBindEntry::Kind::Regular);
+}
+
+iterator_range<bind_iterator> MachOObjectFile::lazyBindTable() const {
+  return bindTable(getDyldInfoLazyBindOpcodes(), is64Bit(),
+                   MachOBindEntry::Kind::Lazy);
+}
+
+iterator_range<bind_iterator> MachOObjectFile::weakBindTable() const {
+  return bindTable(getDyldInfoWeakBindOpcodes(), is64Bit(),
+                   MachOBindEntry::Kind::Weak);
+}
+
 StringRef
 MachOObjectFile::getSectionFinalSegmentName(DataRefImpl Sec) const {
   ArrayRef<char> Raw = getSectionRawFinalSegmentName(Sec);
@@ -1349,16 +2148,18 @@ MachOObjectFile::getSectionFinalSegmentName(DataRefImpl Sec) const {
 
 ArrayRef<char>
 MachOObjectFile::getSectionRawName(DataRefImpl Sec) const {
+  assert(Sec.d.a < Sections.size() && "Should have detected this earlier");
   const section_base *Base =
     reinterpret_cast<const section_base *>(Sections[Sec.d.a]);
-  return ArrayRef<char>(Base->sectname);
+  return makeArrayRef(Base->sectname);
 }
 
 ArrayRef<char>
 MachOObjectFile::getSectionRawFinalSegmentName(DataRefImpl Sec) const {
+  assert(Sec.d.a < Sections.size() && "Should have detected this earlier");
   const section_base *Base =
     reinterpret_cast<const section_base *>(Sections[Sec.d.a]);
-  return ArrayRef<char>(Base->segname);
+  return makeArrayRef(Base->segname);
 }
 
 bool
@@ -1393,6 +2194,11 @@ uint32_t MachOObjectFile::getScatteredRelocationValue(
   return RE.r_word1;
 }
 
+uint32_t MachOObjectFile::getScatteredRelocationType(
+    const MachO::any_relocation_info &RE) const {
+  return (RE.r_word0 >> 24) & 0xf;
+}
+
 unsigned MachOObjectFile::getAnyRelocationAddress(
     const MachO::any_relocation_info &RE) const {
   if (isRelocationScattered(RE))
@@ -1423,10 +2229,10 @@ MachOObjectFile::getAnyRelocationType(
 }
 
 SectionRef
-MachOObjectFile::getRelocationSection(
+MachOObjectFile::getAnyRelocationSection(
                                    const MachO::any_relocation_info &RE) const {
   if (isRelocationScattered(RE) || getPlainRelocationExternal(RE))
-    return *end_sections();
+    return *section_end();
   unsigned SecNum = getPlainRelocationSymbolNum(RE) - 1;
   DataRefImpl DRI;
   DRI.d.a = SecNum;
@@ -1441,6 +2247,8 @@ MachOObjectFile::getFirstLoadCommandInfo() const {
                                     sizeof(MachO::mach_header);
   Load.Ptr = getPtr(this, HeaderSize);
   Load.C = getStruct<MachO::load_command>(this, Load.Ptr);
+  if (Load.C.cmdsize < 8)
+    report_fatal_error("Load command with size < 8 bytes.");
   return Load;
 }
 
@@ -1449,14 +2257,22 @@ MachOObjectFile::getNextLoadCommandInfo(const LoadCommandInfo &L) const {
   MachOObjectFile::LoadCommandInfo Next;
   Next.Ptr = L.Ptr + L.C.cmdsize;
   Next.C = getStruct<MachO::load_command>(this, Next.Ptr);
+  if (Next.C.cmdsize < 8)
+    report_fatal_error("Load command with size < 8 bytes.");
   return Next;
 }
 
 MachO::section MachOObjectFile::getSection(DataRefImpl DRI) const {
+  // TODO: What if Sections.size() == 0?
+  if (DRI.d.a >= Sections.size())
+    report_fatal_error("getSection: Invalid section index.");
   return getStruct<MachO::section>(this, Sections[DRI.d.a]);
 }
 
 MachO::section_64 MachOObjectFile::getSection64(DataRefImpl DRI) const {
+  // TODO: What if Sections.size() == 0?
+  if (DRI.d.a >= Sections.size())
+    report_fatal_error("getSection64: Invalid section index.");
   return getStruct<MachO::section_64>(this, Sections[DRI.d.a]);
 }
 
@@ -1499,15 +2315,113 @@ MachOObjectFile::getSegment64LoadCommand(const LoadCommandInfo &L) const {
   return getStruct<MachO::segment_command_64>(this, L.Ptr);
 }
 
-MachO::linker_options_command
-MachOObjectFile::getLinkerOptionsLoadCommand(const LoadCommandInfo &L) const {
-  return getStruct<MachO::linker_options_command>(this, L.Ptr);
+MachO::linker_option_command
+MachOObjectFile::getLinkerOptionLoadCommand(const LoadCommandInfo &L) const {
+  return getStruct<MachO::linker_option_command>(this, L.Ptr);
+}
+
+MachO::version_min_command
+MachOObjectFile::getVersionMinLoadCommand(const LoadCommandInfo &L) const {
+  return getStruct<MachO::version_min_command>(this, L.Ptr);
+}
+
+MachO::dylib_command
+MachOObjectFile::getDylibIDLoadCommand(const LoadCommandInfo &L) const {
+  return getStruct<MachO::dylib_command>(this, L.Ptr);
+}
+
+MachO::dyld_info_command
+MachOObjectFile::getDyldInfoLoadCommand(const LoadCommandInfo &L) const {
+  return getStruct<MachO::dyld_info_command>(this, L.Ptr);
+}
+
+MachO::dylinker_command
+MachOObjectFile::getDylinkerCommand(const LoadCommandInfo &L) const {
+  return getStruct<MachO::dylinker_command>(this, L.Ptr);
+}
+
+MachO::uuid_command
+MachOObjectFile::getUuidCommand(const LoadCommandInfo &L) const {
+  return getStruct<MachO::uuid_command>(this, L.Ptr);
+}
+
+MachO::rpath_command
+MachOObjectFile::getRpathCommand(const LoadCommandInfo &L) const {
+  return getStruct<MachO::rpath_command>(this, L.Ptr);
+}
+
+MachO::source_version_command
+MachOObjectFile::getSourceVersionCommand(const LoadCommandInfo &L) const {
+  return getStruct<MachO::source_version_command>(this, L.Ptr);
+}
+
+MachO::entry_point_command
+MachOObjectFile::getEntryPointCommand(const LoadCommandInfo &L) const {
+  return getStruct<MachO::entry_point_command>(this, L.Ptr);
+}
+
+MachO::encryption_info_command
+MachOObjectFile::getEncryptionInfoCommand(const LoadCommandInfo &L) const {
+  return getStruct<MachO::encryption_info_command>(this, L.Ptr);
+}
+
+MachO::encryption_info_command_64
+MachOObjectFile::getEncryptionInfoCommand64(const LoadCommandInfo &L) const {
+  return getStruct<MachO::encryption_info_command_64>(this, L.Ptr);
+}
+
+MachO::sub_framework_command
+MachOObjectFile::getSubFrameworkCommand(const LoadCommandInfo &L) const {
+  return getStruct<MachO::sub_framework_command>(this, L.Ptr);
+}
+
+MachO::sub_umbrella_command
+MachOObjectFile::getSubUmbrellaCommand(const LoadCommandInfo &L) const {
+  return getStruct<MachO::sub_umbrella_command>(this, L.Ptr);
+}
+
+MachO::sub_library_command
+MachOObjectFile::getSubLibraryCommand(const LoadCommandInfo &L) const {
+  return getStruct<MachO::sub_library_command>(this, L.Ptr);
+}
+
+MachO::sub_client_command
+MachOObjectFile::getSubClientCommand(const LoadCommandInfo &L) const {
+  return getStruct<MachO::sub_client_command>(this, L.Ptr);
+}
+
+MachO::routines_command
+MachOObjectFile::getRoutinesCommand(const LoadCommandInfo &L) const {
+  return getStruct<MachO::routines_command>(this, L.Ptr);
+}
+
+MachO::routines_command_64
+MachOObjectFile::getRoutinesCommand64(const LoadCommandInfo &L) const {
+  return getStruct<MachO::routines_command_64>(this, L.Ptr);
+}
+
+MachO::thread_command
+MachOObjectFile::getThreadCommand(const LoadCommandInfo &L) const {
+  return getStruct<MachO::thread_command>(this, L.Ptr);
 }
 
 MachO::any_relocation_info
 MachOObjectFile::getRelocation(DataRefImpl Rel) const {
-  const char *P = reinterpret_cast<const char *>(Rel.p);
-  return getStruct<MachO::any_relocation_info>(this, P);
+  DataRefImpl Sec;
+  Sec.d.a = Rel.d.a;
+  uint32_t Offset;
+  if (is64Bit()) {
+    MachO::section_64 Sect = getSection64(Sec);
+    Offset = Sect.reloff;
+  } else {
+    MachO::section Sect = getSection(Sec);
+    Offset = Sect.reloff;
+  }
+
+  auto P = reinterpret_cast<const MachO::any_relocation_info *>(
+      getPtr(this, Offset)) + Rel.d.b;
+  return getStruct<MachO::any_relocation_info>(
+      this, reinterpret_cast<const char *>(P));
 }
 
 MachO::data_in_code_entry
@@ -1539,11 +2453,47 @@ MachOObjectFile::getDataInCodeTableEntry(uint32_t DataOffset,
 }
 
 MachO::symtab_command MachOObjectFile::getSymtabLoadCommand() const {
-  return getStruct<MachO::symtab_command>(this, SymtabLoadCmd);
+  if (SymtabLoadCmd)
+    return getStruct<MachO::symtab_command>(this, SymtabLoadCmd);
+
+  // If there is no SymtabLoadCmd return a load command with zero'ed fields.
+  MachO::symtab_command Cmd;
+  Cmd.cmd = MachO::LC_SYMTAB;
+  Cmd.cmdsize = sizeof(MachO::symtab_command);
+  Cmd.symoff = 0;
+  Cmd.nsyms = 0;
+  Cmd.stroff = 0;
+  Cmd.strsize = 0;
+  return Cmd;
 }
 
 MachO::dysymtab_command MachOObjectFile::getDysymtabLoadCommand() const {
-  return getStruct<MachO::dysymtab_command>(this, DysymtabLoadCmd);
+  if (DysymtabLoadCmd)
+    return getStruct<MachO::dysymtab_command>(this, DysymtabLoadCmd);
+
+  // If there is no DysymtabLoadCmd return a load command with zero'ed fields.
+  MachO::dysymtab_command Cmd;
+  Cmd.cmd = MachO::LC_DYSYMTAB;
+  Cmd.cmdsize = sizeof(MachO::dysymtab_command);
+  Cmd.ilocalsym = 0;
+  Cmd.nlocalsym = 0;
+  Cmd.iextdefsym = 0;
+  Cmd.nextdefsym = 0;
+  Cmd.iundefsym = 0;
+  Cmd.nundefsym = 0;
+  Cmd.tocoff = 0;
+  Cmd.ntoc = 0;
+  Cmd.modtaboff = 0;
+  Cmd.nmodtab = 0;
+  Cmd.extrefsymoff = 0;
+  Cmd.nextrefsyms = 0;
+  Cmd.indirectsymoff = 0;
+  Cmd.nindirectsyms = 0;
+  Cmd.extreloff = 0;
+  Cmd.nextrel = 0;
+  Cmd.locreloff = 0;
+  Cmd.nlocrel = 0;
+  return Cmd;
 }
 
 MachO::linkedit_data_command
@@ -1560,6 +2510,84 @@ MachOObjectFile::getDataInCodeLoadCommand() const {
   return Cmd;
 }
 
+MachO::linkedit_data_command
+MachOObjectFile::getLinkOptHintsLoadCommand() const {
+  if (LinkOptHintsLoadCmd)
+    return getStruct<MachO::linkedit_data_command>(this, LinkOptHintsLoadCmd);
+
+  // If there is no LinkOptHintsLoadCmd return a load command with zero'ed
+  // fields.
+  MachO::linkedit_data_command Cmd;
+  Cmd.cmd = MachO::LC_LINKER_OPTIMIZATION_HINT;
+  Cmd.cmdsize = sizeof(MachO::linkedit_data_command);
+  Cmd.dataoff = 0;
+  Cmd.datasize = 0;
+  return Cmd;
+}
+
+ArrayRef<uint8_t> MachOObjectFile::getDyldInfoRebaseOpcodes() const {
+  if (!DyldInfoLoadCmd) 
+    return ArrayRef<uint8_t>();
+
+  MachO::dyld_info_command DyldInfo 
+                   = getStruct<MachO::dyld_info_command>(this, DyldInfoLoadCmd);
+  const uint8_t *Ptr = reinterpret_cast<const uint8_t*>(
+                                             getPtr(this, DyldInfo.rebase_off));
+  return ArrayRef<uint8_t>(Ptr, DyldInfo.rebase_size);
+}
+
+ArrayRef<uint8_t> MachOObjectFile::getDyldInfoBindOpcodes() const {
+  if (!DyldInfoLoadCmd) 
+    return ArrayRef<uint8_t>();
+
+  MachO::dyld_info_command DyldInfo 
+                   = getStruct<MachO::dyld_info_command>(this, DyldInfoLoadCmd);
+  const uint8_t *Ptr = reinterpret_cast<const uint8_t*>(
+                                               getPtr(this, DyldInfo.bind_off));
+  return ArrayRef<uint8_t>(Ptr, DyldInfo.bind_size);
+}
+
+ArrayRef<uint8_t> MachOObjectFile::getDyldInfoWeakBindOpcodes() const {
+  if (!DyldInfoLoadCmd) 
+    return ArrayRef<uint8_t>();
+
+  MachO::dyld_info_command DyldInfo 
+                   = getStruct<MachO::dyld_info_command>(this, DyldInfoLoadCmd);
+  const uint8_t *Ptr = reinterpret_cast<const uint8_t*>(
+                                          getPtr(this, DyldInfo.weak_bind_off));
+  return ArrayRef<uint8_t>(Ptr, DyldInfo.weak_bind_size);
+}
+
+ArrayRef<uint8_t> MachOObjectFile::getDyldInfoLazyBindOpcodes() const {
+  if (!DyldInfoLoadCmd) 
+    return ArrayRef<uint8_t>();
+
+  MachO::dyld_info_command DyldInfo 
+                   = getStruct<MachO::dyld_info_command>(this, DyldInfoLoadCmd);
+  const uint8_t *Ptr = reinterpret_cast<const uint8_t*>(
+                                          getPtr(this, DyldInfo.lazy_bind_off));
+  return ArrayRef<uint8_t>(Ptr, DyldInfo.lazy_bind_size);
+}
+
+ArrayRef<uint8_t> MachOObjectFile::getDyldInfoExportsTrie() const {
+  if (!DyldInfoLoadCmd) 
+    return ArrayRef<uint8_t>();
+
+  MachO::dyld_info_command DyldInfo 
+                   = getStruct<MachO::dyld_info_command>(this, DyldInfoLoadCmd);
+  const uint8_t *Ptr = reinterpret_cast<const uint8_t*>(
+                                             getPtr(this, DyldInfo.export_off));
+  return ArrayRef<uint8_t>(Ptr, DyldInfo.export_size);
+}
+
+ArrayRef<uint8_t> MachOObjectFile::getUuid() const {
+  if (!UuidLoadCmd)
+    return ArrayRef<uint8_t>();
+  // Returning a pointer is fine as uuid doesn't need endian swapping.
+  const char *Ptr = UuidLoadCmd + offsetof(MachO::uuid_command, uuid);
+  return ArrayRef<uint8_t>(reinterpret_cast<const uint8_t *>(Ptr), 16);
+}
+
 StringRef MachOObjectFile::getStringTableData() const {
   MachO::symtab_command S = getSymtabLoadCommand();
   return getData().substr(S.stroff, S.strsize);
@@ -1582,28 +2610,28 @@ void MachOObjectFile::ReadULEB128s(uint64_t Index,
   }
 }
 
-ErrorOr<ObjectFile *> ObjectFile::createMachOObjectFile(MemoryBuffer *Buffer,
-                                                        bool BufferOwned) {
-  StringRef Magic = Buffer->getBuffer().slice(0, 4);
-  error_code EC;
-  OwningPtr<MachOObjectFile> Ret;
+bool MachOObjectFile::isRelocatableObject() const {
+  return getHeader().filetype == MachO::MH_OBJECT;
+}
+
+ErrorOr<std::unique_ptr<MachOObjectFile>>
+ObjectFile::createMachOObjectFile(MemoryBufferRef Buffer) {
+  StringRef Magic = Buffer.getBuffer().slice(0, 4);
+  std::error_code EC;
+  std::unique_ptr<MachOObjectFile> Ret;
   if (Magic == "\xFE\xED\xFA\xCE")
-    Ret.reset(new MachOObjectFile(Buffer, false, false, EC, BufferOwned));
+    Ret.reset(new MachOObjectFile(Buffer, false, false, EC));
   else if (Magic == "\xCE\xFA\xED\xFE")
-    Ret.reset(new MachOObjectFile(Buffer, true, false, EC, BufferOwned));
+    Ret.reset(new MachOObjectFile(Buffer, true, false, EC));
   else if (Magic == "\xFE\xED\xFA\xCF")
-    Ret.reset(new MachOObjectFile(Buffer, false, true, EC, BufferOwned));
+    Ret.reset(new MachOObjectFile(Buffer, false, true, EC));
   else if (Magic == "\xCF\xFA\xED\xFE")
-    Ret.reset(new MachOObjectFile(Buffer, true, true, EC, BufferOwned));
-  else {
-    delete Buffer;
+    Ret.reset(new MachOObjectFile(Buffer, true, true, EC));
+  else
     return object_error::parse_failed;
-  }
 
   if (EC)
     return EC;
-  return Ret.take();
+  return std::move(Ret);
 }
 
-} // end namespace object
-} // end namespace llvm