Return ErrorOr from getSymbolAddress.
[oota-llvm.git] / lib / Object / MachOObjectFile.cpp
index 4919114d2349752607514bc2fbe5c070ee31de3d..96718335967bb70b8dca85fbd2802427de56151c 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 SwapStruct(T &Value);
-
-template<>
-void SwapStruct(MachO::any_relocation_info &H) {
-  sys::swapByteOrder(H.r_word0);
-  sys::swapByteOrder(H.r_word1);
-}
-
-template<>
-void SwapStruct(MachO::load_command &L) {
-  sys::swapByteOrder(L.cmd);
-  sys::swapByteOrder(L.cmdsize);
-}
-
-template<>
-void SwapStruct(nlist_base &S) {
-  sys::swapByteOrder(S.n_strx);
-  sys::swapByteOrder(S.n_desc);
-}
-
-template<>
-void SwapStruct(MachO::section &S) {
-  sys::swapByteOrder(S.addr);
-  sys::swapByteOrder(S.size);
-  sys::swapByteOrder(S.offset);
-  sys::swapByteOrder(S.align);
-  sys::swapByteOrder(S.reloff);
-  sys::swapByteOrder(S.nreloc);
-  sys::swapByteOrder(S.flags);
-  sys::swapByteOrder(S.reserved1);
-  sys::swapByteOrder(S.reserved2);
-}
-
-template<>
-void SwapStruct(MachO::section_64 &S) {
-  sys::swapByteOrder(S.addr);
-  sys::swapByteOrder(S.size);
-  sys::swapByteOrder(S.offset);
-  sys::swapByteOrder(S.align);
-  sys::swapByteOrder(S.reloff);
-  sys::swapByteOrder(S.nreloc);
-  sys::swapByteOrder(S.flags);
-  sys::swapByteOrder(S.reserved1);
-  sys::swapByteOrder(S.reserved2);
-  sys::swapByteOrder(S.reserved3);
-}
-
-template<>
-void SwapStruct(MachO::nlist &S) {
-  sys::swapByteOrder(S.n_strx);
-  sys::swapByteOrder(S.n_desc);
-  sys::swapByteOrder(S.n_value);
-}
-
-template<>
-void SwapStruct(MachO::nlist_64 &S) {
-  sys::swapByteOrder(S.n_strx);
-  sys::swapByteOrder(S.n_desc);
-  sys::swapByteOrder(S.n_value);
-}
-
-template<>
-void SwapStruct(MachO::mach_header &H) {
-  sys::swapByteOrder(H.magic);
-  sys::swapByteOrder(H.cputype);
-  sys::swapByteOrder(H.cpusubtype);
-  sys::swapByteOrder(H.filetype);
-  sys::swapByteOrder(H.ncmds);
-  sys::swapByteOrder(H.sizeofcmds);
-  sys::swapByteOrder(H.flags);
-}
-
-template<>
-void SwapStruct(MachO::mach_header_64 &H) {
-  sys::swapByteOrder(H.magic);
-  sys::swapByteOrder(H.cputype);
-  sys::swapByteOrder(H.cpusubtype);
-  sys::swapByteOrder(H.filetype);
-  sys::swapByteOrder(H.ncmds);
-  sys::swapByteOrder(H.sizeofcmds);
-  sys::swapByteOrder(H.flags);
-  sys::swapByteOrder(H.reserved);
-}
-
-template<>
-void SwapStruct(MachO::symtab_command &C) {
-  sys::swapByteOrder(C.cmd);
-  sys::swapByteOrder(C.cmdsize);
-  sys::swapByteOrder(C.symoff);
-  sys::swapByteOrder(C.nsyms);
-  sys::swapByteOrder(C.stroff);
-  sys::swapByteOrder(C.strsize);
-}
-
-template<>
-void SwapStruct(MachO::dysymtab_command &C) {
-  sys::swapByteOrder(C.cmd);
-  sys::swapByteOrder(C.cmdsize);
-  sys::swapByteOrder(C.ilocalsym);
-  sys::swapByteOrder(C.nlocalsym);
-  sys::swapByteOrder(C.iextdefsym);
-  sys::swapByteOrder(C.nextdefsym);
-  sys::swapByteOrder(C.iundefsym);
-  sys::swapByteOrder(C.nundefsym);
-  sys::swapByteOrder(C.tocoff);
-  sys::swapByteOrder(C.ntoc);
-  sys::swapByteOrder(C.modtaboff);
-  sys::swapByteOrder(C.nmodtab);
-  sys::swapByteOrder(C.extrefsymoff);
-  sys::swapByteOrder(C.nextrefsyms);
-  sys::swapByteOrder(C.indirectsymoff);
-  sys::swapByteOrder(C.nindirectsyms);
-  sys::swapByteOrder(C.extreloff);
-  sys::swapByteOrder(C.nextrel);
-  sys::swapByteOrder(C.locreloff);
-  sys::swapByteOrder(C.nlocrel);
-}
-
-template<>
-void SwapStruct(MachO::linkedit_data_command &C) {
-  sys::swapByteOrder(C.cmd);
-  sys::swapByteOrder(C.cmdsize);
-  sys::swapByteOrder(C.dataoff);
-  sys::swapByteOrder(C.datasize);
-}
-
-template<>
-void SwapStruct(MachO::segment_command &C) {
-  sys::swapByteOrder(C.cmd);
-  sys::swapByteOrder(C.cmdsize);
-  sys::swapByteOrder(C.vmaddr);
-  sys::swapByteOrder(C.vmsize);
-  sys::swapByteOrder(C.fileoff);
-  sys::swapByteOrder(C.filesize);
-  sys::swapByteOrder(C.maxprot);
-  sys::swapByteOrder(C.initprot);
-  sys::swapByteOrder(C.nsects);
-  sys::swapByteOrder(C.flags);
-}
-
-template<>
-void SwapStruct(MachO::segment_command_64 &C) {
-  sys::swapByteOrder(C.cmd);
-  sys::swapByteOrder(C.cmdsize);
-  sys::swapByteOrder(C.vmaddr);
-  sys::swapByteOrder(C.vmsize);
-  sys::swapByteOrder(C.fileoff);
-  sys::swapByteOrder(C.filesize);
-  sys::swapByteOrder(C.maxprot);
-  sys::swapByteOrder(C.initprot);
-  sys::swapByteOrder(C.nsects);
-  sys::swapByteOrder(C.flags);
-}
-
-template<>
-void SwapStruct(uint32_t &C) {
-  sys::swapByteOrder(C);
-}
-
-template<>
-void SwapStruct(MachO::linker_options_command &C) {
-  sys::swapByteOrder(C.cmd);
-  sys::swapByteOrder(C.cmdsize);
-  sys::swapByteOrder(C.count);
-}
-
-template<>
-void SwapStruct(MachO::version_min_command&C) {
-  sys::swapByteOrder(C.cmd);
-  sys::swapByteOrder(C.cmdsize);
-  sys::swapByteOrder(C.version);
-  sys::swapByteOrder(C.reserved);
-}
-
-template<>
-void SwapStruct(MachO::dylib_command&C) {
-  sys::swapByteOrder(C.cmd);
-  sys::swapByteOrder(C.cmdsize);
-  sys::swapByteOrder(C.dylib.name);
-  sys::swapByteOrder(C.dylib.timestamp);
-  sys::swapByteOrder(C.dylib.current_version);
-  sys::swapByteOrder(C.dylib.compatibility_version);
-}
-
-template<>
-void SwapStruct(MachO::data_in_code_entry &C) {
-  sys::swapByteOrder(C.offset);
-  sys::swapByteOrder(C.length);
-  sys::swapByteOrder(C.kind);
-}
-
-template<typename T>
-T getStruct(const MachOObjectFile *O, const char *P) {
+namespace {
+  struct section_base {
+    char sectname[16];
+    char segname[16];
+  };
+}
+
+// FIXME: Replace all uses of this function with getStructOrErr.
+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;
 }
 
-static uint32_t
-getSegmentLoadCommandNumSections(const MachOObjectFile *O,
-                                 const MachOObjectFile::LoadCommandInfo &L) {
-  if (O->is64Bit()) {
-    MachO::segment_command_64 S = O->getSegment64LoadCommand(L);
-    return S.nsects;
-  }
-  MachO::segment_command S = O->getSegmentLoadCommand(L);
-  return S.nsects;
+template <typename T>
+static ErrorOr<T> getStructOrErr(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())
+    return object_error::parse_failed;
+
+  T Cmd;
+  memcpy(&Cmd, P, sizeof(T));
+  if (O->isLittleEndian() != sys::IsLittleEndianHost)
+    MachO::swapStruct(Cmd);
+  return Cmd;
 }
 
 static const char *
@@ -274,10 +84,10 @@ 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) {
@@ -299,72 +109,6 @@ static unsigned getCPUType(const MachOObjectFile *O) {
   return O->getHeader().cputype;
 }
 
-static void printRelocationTargetName(const MachOObjectFile *O,
-                                      const MachO::any_relocation_info &RE,
-                                      raw_string_ostream &fmt) {
-  bool IsScattered = O->isRelocationScattered(RE);
-
-  // Target of a scattered relocation is an address.  In the interest of
-  // generating pretty output, scan through the symbol table looking for a
-  // symbol that aligns with that address.  If we find one, print it.
-  // Otherwise, we just print the hex address of the target.
-  if (IsScattered) {
-    uint32_t Val = O->getPlainRelocationSymbolNum(RE);
-
-    for (const SymbolRef &Symbol : O->symbols()) {
-      std::error_code ec;
-      uint64_t Addr;
-      StringRef Name;
-
-      if ((ec = Symbol.getAddress(Addr)))
-        report_fatal_error(ec.message());
-      if (Addr != Val)
-        continue;
-      if ((ec = Symbol.getName(Name)))
-        report_fatal_error(ec.message());
-      fmt << Name;
-      return;
-    }
-
-    // If we couldn't find a symbol that this relocation refers to, try
-    // to find a section beginning instead.
-    for (const SectionRef &Section : O->sections()) {
-      std::error_code ec;
-      uint64_t Addr;
-      StringRef Name;
-
-      if ((ec = Section.getAddress(Addr)))
-        report_fatal_error(ec.message());
-      if (Addr != Val)
-        continue;
-      if ((ec = Section.getName(Name)))
-        report_fatal_error(ec.message());
-      fmt << Name;
-      return;
-    }
-
-    fmt << format("0x%x", Val);
-    return;
-  }
-
-  StringRef S;
-  bool isExtern = O->getPlainRelocationExternal(RE);
-  uint64_t Val = O->getPlainRelocationSymbolNum(RE);
-
-  if (isExtern) {
-    symbol_iterator SI = O->symbol_begin();
-    advance(SI, Val);
-    SI->getName(S);
-  } else {
-    section_iterator SI = O->section_begin();
-    // Adjust for the fact that sections are 1-indexed.
-    advance(SI, Val - 1);
-    SI->getName(S);
-  }
-
-  fmt << S;
-}
-
 static uint32_t
 getPlainRelocationAddress(const MachO::any_relocation_info &RE) {
   return RE.r_word0;
@@ -407,11 +151,6 @@ 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()) {
@@ -422,33 +161,146 @@ static uint32_t getSectionFlags(const MachOObjectFile *O,
   return Sect.flags;
 }
 
-MachOObjectFile::MachOObjectFile(std::unique_ptr<MemoryBuffer> Object,
-                                 bool IsLittleEndian, bool Is64bits,
-                                 std::error_code &EC)
-    : ObjectFile(getMachOType(IsLittleEndian, Is64bits), std::move(Object)),
+static ErrorOr<MachOObjectFile::LoadCommandInfo>
+getLoadCommandInfo(const MachOObjectFile *Obj, const char *Ptr) {
+  auto CmdOrErr = getStructOrErr<MachO::load_command>(Obj, Ptr);
+  if (!CmdOrErr)
+    return CmdOrErr.getError();
+  if (CmdOrErr->cmdsize < 8)
+    return object_error::macho_small_load_command;
+  MachOObjectFile::LoadCommandInfo Load;
+  Load.Ptr = Ptr;
+  Load.C = CmdOrErr.get();
+  return Load;
+}
+
+static ErrorOr<MachOObjectFile::LoadCommandInfo>
+getFirstLoadCommandInfo(const MachOObjectFile *Obj) {
+  unsigned HeaderSize = Obj->is64Bit() ? sizeof(MachO::mach_header_64)
+                                       : sizeof(MachO::mach_header);
+  return getLoadCommandInfo(Obj, getPtr(Obj, HeaderSize));
+}
+
+static ErrorOr<MachOObjectFile::LoadCommandInfo>
+getNextLoadCommandInfo(const MachOObjectFile *Obj,
+                       const MachOObjectFile::LoadCommandInfo &L) {
+  return getLoadCommandInfo(Obj, L.Ptr + L.C.cmdsize);
+}
+
+template <typename T>
+static void parseHeader(const MachOObjectFile *Obj, T &Header,
+                        std::error_code &EC) {
+  auto HeaderOrErr = getStructOrErr<T>(Obj, getPtr(Obj, 0));
+  if (HeaderOrErr)
+    Header = HeaderOrErr.get();
+  else
+    EC = HeaderOrErr.getError();
+}
+
+// Parses LC_SEGMENT or LC_SEGMENT_64 load command, adds addresses of all
+// sections to \param Sections, and optionally sets
+// \param IsPageZeroSegment to true.
+template <typename SegmentCmd>
+static std::error_code parseSegmentLoadCommand(
+    const MachOObjectFile *Obj, const MachOObjectFile::LoadCommandInfo &Load,
+    SmallVectorImpl<const char *> &Sections, bool &IsPageZeroSegment) {
+  const unsigned SegmentLoadSize = sizeof(SegmentCmd);
+  if (Load.C.cmdsize < SegmentLoadSize)
+    return object_error::macho_load_segment_too_small;
+  auto SegOrErr = getStructOrErr<SegmentCmd>(Obj, Load.Ptr);
+  if (!SegOrErr)
+    return SegOrErr.getError();
+  SegmentCmd S = SegOrErr.get();
+  const unsigned SectionSize =
+      Obj->is64Bit() ? sizeof(MachO::section_64) : sizeof(MachO::section);
+  if (S.nsects > std::numeric_limits<uint32_t>::max() / SectionSize ||
+      S.nsects * SectionSize > Load.C.cmdsize - SegmentLoadSize)
+    return object_error::macho_load_segment_too_many_sections;
+  for (unsigned J = 0; J < S.nsects; ++J) {
+    const char *Sec = getSectionPtr(Obj, Load, J);
+    Sections.push_back(Sec);
+  }
+  IsPageZeroSegment |= StringRef("__PAGEZERO").equals(S.segname);
+  return std::error_code();
+}
+
+MachOObjectFile::MachOObjectFile(MemoryBufferRef Object, bool IsLittleEndian,
+                                 bool Is64bits, std::error_code &EC)
+    : ObjectFile(getMachOType(IsLittleEndian, Is64bits), Object),
       SymtabLoadCmd(nullptr), DysymtabLoadCmd(nullptr),
-      DataInCodeLoadCmd(nullptr) {
-  uint32_t LoadCommandCount = this->getHeader().ncmds;
-  MachO::LoadCommandType SegmentLoadType = is64Bit() ?
-    MachO::LC_SEGMENT_64 : MachO::LC_SEGMENT;
+      DataInCodeLoadCmd(nullptr), LinkOptHintsLoadCmd(nullptr),
+      DyldInfoLoadCmd(nullptr), UuidLoadCmd(nullptr),
+      HasPageZeroSegment(false) {
+  if (is64Bit())
+    parseHeader(this, Header64, EC);
+  else
+    parseHeader(this, Header, EC);
+  if (EC)
+    return;
 
-  MachOObjectFile::LoadCommandInfo Load = getFirstLoadCommandInfo();
-  for (unsigned I = 0; ; ++I) {
+  uint32_t LoadCommandCount = getHeader().ncmds;
+  if (LoadCommandCount == 0)
+    return;
+
+  auto LoadOrErr = getFirstLoadCommandInfo(this);
+  if (!LoadOrErr) {
+    EC = LoadOrErr.getError();
+    return;
+  }
+  LoadCommandInfo Load = LoadOrErr.get();
+  for (unsigned I = 0; I < LoadCommandCount; ++I) {
+    LoadCommands.push_back(Load);
     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 == SegmentLoadType) {
-      uint32_t NumSections = getSegmentLoadCommandNumSections(this, Load);
-      for (unsigned J = 0; J < NumSections; ++J) {
-        const char *Sec = getSectionPtr(this, Load, J);
-        Sections.push_back(Sec);
+    } 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 == MachO::LC_SEGMENT_64) {
+      if ((EC = parseSegmentLoadCommand<MachO::segment_command_64>(
+               this, Load, Sections, HasPageZeroSegment)))
+        return;
+    } else if (Load.C.cmd == MachO::LC_SEGMENT) {
+      if ((EC = parseSegmentLoadCommand<MachO::segment_command>(
+               this, Load, Sections, HasPageZeroSegment)))
+        return;
     } 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 ||
@@ -456,12 +308,16 @@ MachOObjectFile::MachOObjectFile(std::unique_ptr<MemoryBuffer> Object,
                Load.C.cmd == MachO::LC_LOAD_UPWARD_DYLIB) {
       Libraries.push_back(Load.Ptr);
     }
-
-    if (I == LoadCommandCount - 1)
-      break;
-    else
-      Load = getNextLoadCommandInfo(Load);
+    if (I < LoadCommandCount - 1) {
+      auto LoadOrErr = getNextLoadCommandInfo(this, Load);
+      if (!LoadOrErr) {
+        EC = LoadOrErr.getError();
+        return;
+      }
+      Load = LoadOrErr.get();
+    }
   }
+  assert(LoadCommands.size() == LoadCommandCount);
 }
 
 void MachOObjectFile::moveSymbolNext(DataRefImpl &Symb) const {
@@ -471,13 +327,29 @@ void MachOObjectFile::moveSymbolNext(DataRefImpl &Symb) const {
   Symb.p += SymbolTableEntrySize;
 }
 
-std::error_code MachOObjectFile::getSymbolName(DataRefImpl Symb,
-                                               StringRef &Res) const {
+ErrorOr<StringRef> MachOObjectFile::getSymbolName(DataRefImpl Symb) 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];
-  Res = StringRef(Start);
-  return object_error::success;
+  if (Start < getData().begin() || Start >= getData().end())
+    report_fatal_error(
+        "Symbol name entry points before beginning or past end of file.");
+  return StringRef(Start);
+}
+
+unsigned MachOObjectFile::getSectionType(SectionRef Sec) const {
+  DataRefImpl DRI = Sec.getRawDataRefImpl();
+  uint32_t Flags = getSectionFlags(this, DRI);
+  return Flags & MachO::SECTION_TYPE;
+}
+
+uint64_t MachOObjectFile::getNValue(DataRefImpl Sym) const {
+  if (is64Bit()) {
+    MachO::nlist_64 Entry = getSymbol64TableEntry(Sym);
+    return Entry.n_value;
+  }
+  MachO::nlist Entry = getSymbolTableEntry(Sym);
+  return Entry.n_value;
 }
 
 // getIndirectName() returns the name of the alias'ed symbol who's string table
@@ -485,132 +357,61 @@ std::error_code MachOObjectFile::getSymbolName(DataRefImpl Symb,
 std::error_code MachOObjectFile::getIndirectName(DataRefImpl Symb,
                                                  StringRef &Res) const {
   StringRef StringTable = getStringTableData();
-  uint64_t NValue;
-  if (is64Bit()) {
-    MachO::nlist_64 Entry = getSymbol64TableEntry(Symb);
-    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);
-    NValue = Entry.n_value;
-    if ((Entry.n_type & MachO::N_TYPE) != MachO::N_INDR)
-      return object_error::parse_failed;
-  }
+  MachO::nlist_base Entry = getSymbolTableEntryBase(this, Symb);
+  if ((Entry.n_type & MachO::N_TYPE) != MachO::N_INDR)
+    return object_error::parse_failed;
+  uint64_t NValue = getNValue(Symb);
   if (NValue >= StringTable.size())
     return object_error::parse_failed;
   const char *Start = &StringTable.data()[NValue];
   Res = StringRef(Start);
-  return object_error::success;
+  return std::error_code();
 }
 
-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;
+uint64_t MachOObjectFile::getSymbolValue(DataRefImpl Sym) const {
+  uint64_t NValue = getNValue(Sym);
+  MachO::nlist_base Entry = getSymbolTableEntryBase(this, Sym);
+  if ((Entry.n_type & MachO::N_TYPE) == MachO::N_UNDF && NValue == 0)
+    return UnknownAddress;
+  return NValue;
+}
+
+ErrorOr<uint64_t> MachOObjectFile::getSymbolAddress(DataRefImpl Sym) const {
+  return getSymbolValue(Sym);
 }
 
-std::error_code MachOObjectFile::getSymbolAlignment(DataRefImpl DRI,
-                                                    uint32_t &Result) const {
+uint32_t MachOObjectFile::getSymbolAlignment(DataRefImpl DRI) const {
   uint32_t flags = getSymbolFlags(DRI);
   if (flags & SymbolRef::SF_Common) {
-    nlist_base Entry = getSymbolTableEntryBase(this, DRI);
-    Result = 1 << MachO::GET_COMM_ALIGN(Entry.n_desc);
-  } else {
-    Result = 0;
+    MachO::nlist_base Entry = getSymbolTableEntryBase(this, DRI);
+    return 1 << MachO::GET_COMM_ALIGN(Entry.n_desc);
   }
-  return object_error::success;
+  return 0;
 }
 
-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);
-  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 = getSymbolFlags(DRI);
-    if (flags & SymbolRef::SF_Common)
-      Result = Value;
-    else
-      Result = UnknownAddressOrSize;
-    return object_error::success;
-  }
-  // Unfortunately symbols are unsorted so we need to touch all
-  // symbols from load command
-  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);
-    EndOffset += Size;
-  }
-  Result = EndOffset - BeginOffset;
-  return object_error::success;
+uint64_t MachOObjectFile::getCommonSymbolSizeImpl(DataRefImpl DRI) const {
+  return getSymbolValue(DRI);
 }
 
-std::error_code MachOObjectFile::getSymbolType(DataRefImpl Symb,
-                                               SymbolRef::Type &Res) const {
-  nlist_base Entry = getSymbolTableEntryBase(this, Symb);
+SymbolRef::Type MachOObjectFile::getSymbolType(DataRefImpl Symb) const {
+  MachO::nlist_base Entry = getSymbolTableEntryBase(this, Symb);
   uint8_t n_type = Entry.n_type;
 
-  Res = SymbolRef::ST_Other;
-
   // If this is a STAB debugging symbol, we can do nothing more.
-  if (n_type & MachO::N_STAB) {
-    Res = SymbolRef::ST_Debug;
-    return object_error::success;
-  }
+  if (n_type & MachO::N_STAB)
+    return SymbolRef::ST_Debug;
 
   switch (n_type & MachO::N_TYPE) {
     case MachO::N_UNDF :
-      Res = SymbolRef::ST_Unknown;
-      break;
+      return SymbolRef::ST_Unknown;
     case MachO::N_SECT :
-      Res = SymbolRef::ST_Function;
-      break;
+      return SymbolRef::ST_Function;
   }
-  return object_error::success;
+  return SymbolRef::ST_Other;
 }
 
 uint32_t MachOObjectFile::getSymbolFlags(DataRefImpl DRI) const {
-  nlist_base Entry = getSymbolTableEntryBase(this, DRI);
+  MachO::nlist_base Entry = getSymbolTableEntryBase(this, DRI);
 
   uint8_t MachOType = Entry.n_type;
   uint16_t MachOFlags = Entry.n_desc;
@@ -629,16 +430,21 @@ uint32_t MachOObjectFile::getSymbolFlags(DataRefImpl DRI) const {
   if (MachOType & MachO::N_EXT) {
     Result |= SymbolRef::SF_Global;
     if ((MachOType & MachO::N_TYPE) == MachO::N_UNDF) {
-      uint64_t Value;
-      getSymbolAddress(DRI, Value);
-      if (Value && Value != UnknownAddressOrSize)
+      uint64_t Value = getSymbolValue(DRI);
+      if (Value && Value != UnknownAddress)
         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;
 
@@ -647,7 +453,7 @@ uint32_t MachOObjectFile::getSymbolFlags(DataRefImpl DRI) const {
 
 std::error_code MachOObjectFile::getSymbolSection(DataRefImpl Symb,
                                                   section_iterator &Res) const {
-  nlist_base Entry = getSymbolTableEntryBase(this, Symb);
+  MachO::nlist_base Entry = getSymbolTableEntryBase(this, Symb);
   uint8_t index = Entry.n_sect;
 
   if (index == 0) {
@@ -655,10 +461,18 @@ std::error_code MachOObjectFile::getSymbolSection(DataRefImpl Symb,
   } 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;
+  return std::error_code();
+}
+
+unsigned MachOObjectFile::getSymbolSectionID(SymbolRef Sym) const {
+  MachO::nlist_base Entry =
+      getSymbolTableEntryBase(this, Sym.getRawDataRefImpl());
+  return Entry.n_sect - 1;
 }
 
 void MachOObjectFile::moveSectionNext(DataRefImpl &Sec) const {
@@ -669,32 +483,19 @@ std::error_code MachOObjectFile::getSectionName(DataRefImpl Sec,
                                                 StringRef &Result) const {
   ArrayRef<char> Raw = getSectionRawName(Sec);
   Result = parseSegmentOrSectionName(Raw.data());
-  return object_error::success;
+  return std::error_code();
 }
 
-std::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;
 }
 
-std::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;
 }
 
 std::error_code MachOObjectFile::getSectionContents(DataRefImpl Sec,
@@ -713,11 +514,10 @@ std::error_code MachOObjectFile::getSectionContents(DataRefImpl Sec,
   }
 
   Res = this->getData().substr(Offset, Size);
-  return object_error::success;
+  return std::error_code();
 }
 
-std::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);
@@ -727,92 +527,37 @@ std::error_code MachOObjectFile::getSectionAlignment(DataRefImpl Sec,
     Align = Sect.align;
   }
 
-  Res = uint64_t(1) << Align;
-  return object_error::success;
+  return uint64_t(1) << Align;
 }
 
-std::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;
+  return Flags & MachO::S_ATTR_PURE_INSTRUCTIONS;
 }
 
-std::error_code MachOObjectFile::isSectionData(DataRefImpl Sec,
-                                               bool &Result) const {
+bool MachOObjectFile::isSectionData(DataRefImpl Sec) const {
   uint32_t Flags = getSectionFlags(this, Sec);
   unsigned SectionType = Flags & MachO::SECTION_TYPE;
-  Result = !(Flags & MachO::S_ATTR_PURE_INSTRUCTIONS) &&
-           !(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);
 }
 
-std::error_code MachOObjectFile::isSectionBSS(DataRefImpl Sec,
-                                              bool &Result) const {
+bool MachOObjectFile::isSectionBSS(DataRefImpl Sec) const {
   uint32_t Flags = getSectionFlags(this, Sec);
   unsigned SectionType = Flags & MachO::SECTION_TYPE;
-  Result = !(Flags & MachO::S_ATTR_PURE_INSTRUCTIONS) &&
-           (SectionType == MachO::S_ZEROFILL ||
-            SectionType == MachO::S_GB_ZEROFILL);
-  return object_error::success;
-}
-
-std::error_code
-MachOObjectFile::isSectionRequiredForExecution(DataRefImpl Sec,
-                                               bool &Result) const {
-  // FIXME: Unimplemented.
-  Result = true;
-  return object_error::success;
+  return !(Flags & MachO::S_ATTR_PURE_INSTRUCTIONS) &&
+         (SectionType == MachO::S_ZEROFILL ||
+          SectionType == MachO::S_GB_ZEROFILL);
 }
 
-std::error_code MachOObjectFile::isSectionVirtual(DataRefImpl Sec,
-                                                  bool &Result) const {
-  // FIXME: Unimplemented.
-  Result = false;
-  return object_error::success;
-}
-
-std::error_code MachOObjectFile::isSectionZeroInit(DataRefImpl Sec,
-                                                   bool &Res) 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;
+unsigned MachOObjectFile::getSectionID(SectionRef Sec) const {
+  return Sec.getRawDataRefImpl().d.a;
 }
 
-std::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;
-}
-
-std::error_code MachOObjectFile::sectionContainsSymbol(DataRefImpl Sec,
-                                                       DataRefImpl Symb,
-                                                       bool &Result) const {
-  SymbolRef::Type ST;
-  this->getSymbolType(Symb, ST);
-  if (ST == SymbolRef::ST_Unknown) {
-    Result = false;
-    return object_error::success;
-  }
-
-  uint64_t SectBegin, SectEnd;
-  getSectionAddress(Sec, SectBegin);
-  getSectionSize(Sec, SectEnd);
-  SectEnd += SectBegin;
-
-  uint64_t SymAddr;
-  getSymbolAddress(Symb, SymAddr);
-  Result = (SymAddr >= SectBegin) && (SymAddr < SectEnd);
-
-  return object_error::success;
+  return false;
 }
 
 relocation_iterator MachOObjectFile::section_rel_begin(DataRefImpl Sec) const {
@@ -843,26 +588,20 @@ void MachOObjectFile::moveRelocationNext(DataRefImpl &Rel) const {
   ++Rel.d.b;
 }
 
-std::error_code MachOObjectFile::getRelocationAddress(DataRefImpl Rel,
-                                                      uint64_t &Res) const {
-  uint64_t Offset;
-  getRelocationOffset(Rel, Offset);
+ErrorOr<uint64_t> MachOObjectFile::getRelocationAddress(DataRefImpl Rel) const {
+  uint64_t Offset = getRelocationOffset(Rel);
 
   DataRefImpl Sec;
   Sec.d.a = Rel.d.a;
-  uint64_t SecAddress;
-  getSectionAddress(Sec, SecAddress);
-  Res = SecAddress + Offset;
-  return object_error::success;
+  uint64_t SecAddress = getSectionAddress(Sec);
+  return SecAddress + Offset;
 }
 
-std::error_code MachOObjectFile::getRelocationOffset(DataRefImpl Rel,
-                                                     uint64_t &Res) const {
+uint64_t MachOObjectFile::getRelocationOffset(DataRefImpl Rel) 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;
+  return getAnyRelocationAddress(RE);
 }
 
 symbol_iterator
@@ -886,19 +625,20 @@ MachOObjectFile::getRelocationSymbol(DataRefImpl Rel) const {
   return symbol_iterator(SymbolRef(Sym, this));
 }
 
-std::error_code MachOObjectFile::getRelocationType(DataRefImpl Rel,
-                                                   uint64_t &Res) const {
+section_iterator
+MachOObjectFile::getRelocationSection(DataRefImpl Rel) const {
+  return section_iterator(getAnyRelocationSection(getRelocation(Rel)));
+}
+
+uint64_t MachOObjectFile::getRelocationType(DataRefImpl Rel) const {
   MachO::any_relocation_info RE = getRelocation(Rel);
-  Res = getAnyRelocationType(RE);
-  return object_error::success;
+  return getAnyRelocationType(RE);
 }
 
-std::error_code
-MachOObjectFile::getRelocationTypeName(DataRefImpl Rel,
-                                       SmallVectorImpl<char> &Result) const {
+void MachOObjectFile::getRelocationTypeName(
+    DataRefImpl Rel, SmallVectorImpl<char> &Result) const {
   StringRef res;
-  uint64_t RType;
-  getRelocationType(Rel, RType);
+  uint64_t RType = getRelocationType(Rel);
 
   unsigned Arch = this->getArch();
 
@@ -956,7 +696,6 @@ MachOObjectFile::getRelocationTypeName(DataRefImpl Rel,
         res = Table[RType];
       break;
     }
-    case Triple::arm64:
     case Triple::aarch64: {
       static const char *const Table[] = {
         "ARM64_RELOC_UNSIGNED",           "ARM64_RELOC_SUBTRACTOR",
@@ -1003,221 +742,11 @@ MachOObjectFile::getRelocationTypeName(DataRefImpl Rel,
       break;
   }
   Result.append(res.begin(), res.end());
-  return object_error::success;
 }
 
-std::error_code
-MachOObjectFile::getRelocationValueString(DataRefImpl Rel,
-                                          SmallVectorImpl<char> &Result) const {
+uint8_t MachOObjectFile::getRelocationLength(DataRefImpl Rel) const {
   MachO::any_relocation_info RE = getRelocation(Rel);
-
-  unsigned Arch = this->getArch();
-
-  std::string fmtbuf;
-  raw_string_ostream fmt(fmtbuf);
-  unsigned Type = this->getAnyRelocationType(RE);
-  bool IsPCRel = this->getAnyRelocationPCRel(RE);
-
-  // Determine any addends that should be displayed with the relocation.
-  // These require decoding the relocation type, which is triple-specific.
-
-  // X86_64 has entirely custom relocation types.
-  if (Arch == Triple::x86_64) {
-    bool isPCRel = getAnyRelocationPCRel(RE);
-
-    switch (Type) {
-      case MachO::X86_64_RELOC_GOT_LOAD:
-      case MachO::X86_64_RELOC_GOT: {
-        printRelocationTargetName(this, RE, fmt);
-        fmt << "@GOT";
-        if (isPCRel) fmt << "PCREL";
-        break;
-      }
-      case MachO::X86_64_RELOC_SUBTRACTOR: {
-        DataRefImpl RelNext = Rel;
-        moveRelocationNext(RelNext);
-        MachO::any_relocation_info RENext = getRelocation(RelNext);
-
-        // X86_64_RELOC_SUBTRACTOR must be followed by a relocation of type
-        // X86_64_RELOC_UNSIGNED.
-        // NOTE: Scattered relocations don't exist on x86_64.
-        unsigned RType = getAnyRelocationType(RENext);
-        if (RType != MachO::X86_64_RELOC_UNSIGNED)
-          report_fatal_error("Expected X86_64_RELOC_UNSIGNED after "
-                             "X86_64_RELOC_SUBTRACTOR.");
-
-        // The X86_64_RELOC_UNSIGNED contains the minuend symbol;
-        // X86_64_RELOC_SUBTRACTOR contains the subtrahend.
-        printRelocationTargetName(this, RENext, fmt);
-        fmt << "-";
-        printRelocationTargetName(this, RE, fmt);
-        break;
-      }
-      case MachO::X86_64_RELOC_TLV:
-        printRelocationTargetName(this, RE, fmt);
-        fmt << "@TLV";
-        if (isPCRel) fmt << "P";
-        break;
-      case MachO::X86_64_RELOC_SIGNED_1:
-        printRelocationTargetName(this, RE, fmt);
-        fmt << "-1";
-        break;
-      case MachO::X86_64_RELOC_SIGNED_2:
-        printRelocationTargetName(this, RE, fmt);
-        fmt << "-2";
-        break;
-      case MachO::X86_64_RELOC_SIGNED_4:
-        printRelocationTargetName(this, RE, fmt);
-        fmt << "-4";
-        break;
-      default:
-        printRelocationTargetName(this, RE, fmt);
-        break;
-    }
-  // X86 and ARM share some relocation types in common.
-  } else if (Arch == Triple::x86 || Arch == Triple::arm ||
-             Arch == Triple::ppc) {
-    // Generic relocation types...
-    switch (Type) {
-      case MachO::GENERIC_RELOC_PAIR: // prints no info
-        return object_error::success;
-      case MachO::GENERIC_RELOC_SECTDIFF: {
-        DataRefImpl RelNext = Rel;
-        moveRelocationNext(RelNext);
-        MachO::any_relocation_info RENext = getRelocation(RelNext);
-
-        // X86 sect diff's must be followed by a relocation of type
-        // GENERIC_RELOC_PAIR.
-        unsigned RType = getAnyRelocationType(RENext);
-
-        if (RType != MachO::GENERIC_RELOC_PAIR)
-          report_fatal_error("Expected GENERIC_RELOC_PAIR after "
-                             "GENERIC_RELOC_SECTDIFF.");
-
-        printRelocationTargetName(this, RE, fmt);
-        fmt << "-";
-        printRelocationTargetName(this, RENext, fmt);
-        break;
-      }
-    }
-
-    if (Arch == Triple::x86 || Arch == Triple::ppc) {
-      switch (Type) {
-        case MachO::GENERIC_RELOC_LOCAL_SECTDIFF: {
-          DataRefImpl RelNext = Rel;
-          moveRelocationNext(RelNext);
-          MachO::any_relocation_info RENext = getRelocation(RelNext);
-
-          // X86 sect diff's must be followed by a relocation of type
-          // GENERIC_RELOC_PAIR.
-          unsigned RType = getAnyRelocationType(RENext);
-          if (RType != MachO::GENERIC_RELOC_PAIR)
-            report_fatal_error("Expected GENERIC_RELOC_PAIR after "
-                               "GENERIC_RELOC_LOCAL_SECTDIFF.");
-
-          printRelocationTargetName(this, RE, fmt);
-          fmt << "-";
-          printRelocationTargetName(this, RENext, fmt);
-          break;
-        }
-        case MachO::GENERIC_RELOC_TLV: {
-          printRelocationTargetName(this, RE, fmt);
-          fmt << "@TLV";
-          if (IsPCRel) fmt << "P";
-          break;
-        }
-        default:
-          printRelocationTargetName(this, RE, fmt);
-      }
-    } else { // ARM-specific relocations
-      switch (Type) {
-        case MachO::ARM_RELOC_HALF:
-        case MachO::ARM_RELOC_HALF_SECTDIFF: {
-          // Half relocations steal a bit from the length field to encode
-          // whether this is an upper16 or a lower16 relocation.
-          bool isUpper = getAnyRelocationLength(RE) >> 1;
-
-          if (isUpper)
-            fmt << ":upper16:(";
-          else
-            fmt << ":lower16:(";
-          printRelocationTargetName(this, RE, fmt);
-
-          DataRefImpl RelNext = Rel;
-          moveRelocationNext(RelNext);
-          MachO::any_relocation_info RENext = getRelocation(RelNext);
-
-          // ARM half relocs must be followed by a relocation of type
-          // ARM_RELOC_PAIR.
-          unsigned RType = getAnyRelocationType(RENext);
-          if (RType != MachO::ARM_RELOC_PAIR)
-            report_fatal_error("Expected ARM_RELOC_PAIR after "
-                               "ARM_RELOC_HALF");
-
-          // NOTE: The half of the target virtual address is stashed in the
-          // address field of the secondary relocation, but we can't reverse
-          // engineer the constant offset from it without decoding the movw/movt
-          // instruction to find the other half in its immediate field.
-
-          // ARM_RELOC_HALF_SECTDIFF encodes the second section in the
-          // symbol/section pointer of the follow-on relocation.
-          if (Type == MachO::ARM_RELOC_HALF_SECTDIFF) {
-            fmt << "-";
-            printRelocationTargetName(this, RENext, fmt);
-          }
-
-          fmt << ")";
-          break;
-        }
-        default: {
-          printRelocationTargetName(this, RE, fmt);
-        }
-      }
-    }
-  } else
-    printRelocationTargetName(this, RE, fmt);
-
-  fmt.flush();
-  Result.append(fmtbuf.begin(), fmtbuf.end());
-  return object_error::success;
-}
-
-std::error_code MachOObjectFile::getRelocationHidden(DataRefImpl Rel,
-                                                     bool &Result) const {
-  unsigned Arch = getArch();
-  uint64_t Type;
-  getRelocationType(Rel, Type);
-
-  Result = false;
-
-  // On arches that use the generic relocations, GENERIC_RELOC_PAIR
-  // is always hidden.
-  if (Arch == Triple::x86 || Arch == Triple::arm || Arch == Triple::ppc) {
-    if (Type == MachO::GENERIC_RELOC_PAIR) Result = true;
-  } else if (Arch == Triple::x86_64) {
-    // On x86_64, X86_64_RELOC_UNSIGNED is hidden only when it follows
-    // an X86_64_RELOC_SUBTRACTOR.
-    if (Type == MachO::X86_64_RELOC_UNSIGNED && Rel.d.a > 0) {
-      DataRefImpl RelPrev = Rel;
-      RelPrev.d.a--;
-      uint64_t PrevType;
-      getRelocationType(RelPrev, PrevType);
-      if (PrevType == MachO::X86_64_RELOC_SUBTRACTOR)
-        Result = true;
-    }
-  }
-
-  return object_error::success;
-}
-
-std::error_code MachOObjectFile::getLibraryNext(DataRefImpl LibData,
-                                                LibraryRef &Res) const {
-  report_fatal_error("Needed libraries unimplemented in MachOObjectFile");
-}
-
-std::error_code MachOObjectFile::getLibraryPath(DataRefImpl LibData,
-                                                StringRef &Res) const {
-  report_fatal_error("Needed libraries unimplemented in MachOObjectFile");
+  return getAnyRelocationLength(RE);
 }
 
 //
@@ -1368,31 +897,26 @@ guess_qtx:
 // 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) {
+                                                         StringRef &Res) const {
   if (Index >= Libraries.size())
     return object_error::parse_failed;
 
-  MachO::dylib_command D =
-    getStruct<MachO::dylib_command>(this, Libraries[Index]);
-  if (D.dylib.name >= D.cmdsize)
-    return object_error::parse_failed;
-
   // 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) {
-        LibrariesShortNames.push_back(StringRef());
-        continue;
-      }
+      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 == StringRef())
+      if (shortName.empty())
         LibrariesShortNames.push_back(Name);
       else
         LibrariesShortNames.push_back(shortName);
@@ -1400,7 +924,7 @@ std::error_code MachOObjectFile::getLibraryShortNameByIndex(unsigned Index,
   }
 
   Res = LibrariesShortNames[Index];
-  return object_error::success;
+  return std::error_code();
 }
 
 basic_symbol_iterator MachOObjectFile::symbol_begin_impl() const {
@@ -1428,7 +952,8 @@ basic_symbol_iterator MachOObjectFile::getSymbolByIndex(unsigned Index) const {
     return basic_symbol_iterator(SymbolRef(DRI, this));
 
   MachO::symtab_command Symtab = getSymtabLoadCommand();
-  assert(Index < Symtab.nsyms && "Requested symbol index is out of range.");
+  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));
@@ -1447,16 +972,6 @@ section_iterator MachOObjectFile::section_end() const {
   return section_iterator(SectionRef(DRI, this));
 }
 
-library_iterator MachOObjectFile::needed_library_begin() const {
-  // TODO: implement
-  report_fatal_error("Needed libraries unimplemented in MachOObjectFile");
-}
-
-library_iterator MachOObjectFile::needed_library_end() const {
-  // TODO: implement
-  report_fatal_error("Needed libraries unimplemented in MachOObjectFile");
-}
-
 uint8_t MachOObjectFile::getBytesInAddress() const {
   return is64Bit() ? 8 : 4;
 }
@@ -1472,17 +987,10 @@ 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";
@@ -1504,7 +1012,7 @@ Triple::ArchType MachOObjectFile::getArch(uint32_t CPUType) {
   case llvm::MachO::CPU_TYPE_ARM:
     return Triple::arm;
   case llvm::MachO::CPU_TYPE_ARM64:
-    return Triple::arm64;
+    return Triple::aarch64;
   case llvm::MachO::CPU_TYPE_POWERPC:
     return Triple::ppc;
   case llvm::MachO::CPU_TYPE_POWERPC64:
@@ -1514,7 +1022,11 @@ Triple::ArchType MachOObjectFile::getArch(uint32_t CPUType) {
   }
 }
 
-Triple MachOObjectFile::getArch(uint32_t CPUType, uint32_t CPUSubType) {
+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) {
@@ -1538,15 +1050,25 @@ Triple MachOObjectFile::getArch(uint32_t CPUType, uint32_t CPUSubType) {
       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");
@@ -1579,50 +1101,90 @@ Triple MachOObjectFile::getArch(uint32_t CPUType, uint32_t CPUSubType) {
   }
 }
 
+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());
 }
 
-Triple MachOObjectFile::getArch(StringRef ArchFlag) {
-  if (ArchFlag == "i386")
-    return Triple("i386-apple-darwin");
-  else if (ArchFlag == "x86_64")
-    return Triple("x86_64-apple-darwin");
-  else if (ArchFlag == "x86_64h")
-    return Triple("x86_64h-apple-darwin");
-  else if (ArchFlag == "armv4t" || ArchFlag == "arm")
-    return Triple("armv4t-apple-darwin");
-  else if (ArchFlag == "armv5e")
-    return Triple("armv5e-apple-darwin");
-  else if (ArchFlag == "armv6")
-    return Triple("armv6-apple-darwin");
-  else if (ArchFlag == "armv6m")
-    return Triple("armv6m-apple-darwin");
-  else if (ArchFlag == "armv7em")
-    return Triple("armv7em-apple-darwin");
-  else if (ArchFlag == "armv7k")
-    return Triple("armv7k-apple-darwin");
-  else if (ArchFlag == "armv7k")
-    return Triple("armv7m-apple-darwin");
-  else if (ArchFlag == "armv7s")
-    return Triple("armv7s-apple-darwin");
-  else if (ArchFlag == "arm64")
-    return Triple("arm64-apple-darwin");
-  else if (ArchFlag == "ppc")
-    return Triple("ppc-apple-darwin");
-  else if (ArchFlag == "ppc64")
-    return Triple("ppc64-apple-darwin");
-  else
-    return Triple();
+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("armv7", 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 {
+  *ThumbTriple = getThumbArch(Header.cputype, Header.cpusubtype, McpuDefault);
+  return getArch(Header.cputype, Header.cpusubtype, McpuDefault);
 }
 
 relocation_iterator MachOObjectFile::section_rel_begin(unsigned Index) const {
@@ -1658,6 +1220,639 @@ 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);
+}
+
+MachOObjectFile::load_command_iterator
+MachOObjectFile::begin_load_commands() const {
+  return LoadCommands.begin();
+}
+
+MachOObjectFile::load_command_iterator
+MachOObjectFile::end_load_commands() const {
+  return LoadCommands.end();
+}
+
+iterator_range<MachOObjectFile::load_command_iterator>
+MachOObjectFile::load_commands() const {
+  return iterator_range<load_command_iterator>(begin_load_commands(),
+                                               end_load_commands());
+}
+
 StringRef
 MachOObjectFile::getSectionFinalSegmentName(DataRefImpl Sec) const {
   ArrayRef<char> Raw = getSectionRawFinalSegmentName(Sec);
@@ -1666,16 +1861,18 @@ 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
@@ -1710,6 +1907,11 @@ 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))
@@ -1740,40 +1942,25 @@ MachOObjectFile::getAnyRelocationType(
 }
 
 SectionRef
-MachOObjectFile::getRelocationSection(
+MachOObjectFile::getAnyRelocationSection(
                                    const MachO::any_relocation_info &RE) const {
   if (isRelocationScattered(RE) || getPlainRelocationExternal(RE))
     return *section_end();
-  unsigned SecNum = getPlainRelocationSymbolNum(RE) - 1;
+  unsigned SecNum = getPlainRelocationSymbolNum(RE);
+  if (SecNum == MachO::R_ABS || SecNum > Sections.size())
+    return *section_end();
   DataRefImpl DRI;
-  DRI.d.a = SecNum;
+  DRI.d.a = SecNum - 1;
   return SectionRef(DRI, this);
 }
 
-MachOObjectFile::LoadCommandInfo
-MachOObjectFile::getFirstLoadCommandInfo() const {
-  MachOObjectFile::LoadCommandInfo Load;
-
-  unsigned HeaderSize = is64Bit() ? sizeof(MachO::mach_header_64) :
-                                    sizeof(MachO::mach_header);
-  Load.Ptr = getPtr(this, HeaderSize);
-  Load.C = getStruct<MachO::load_command>(this, Load.Ptr);
-  return Load;
-}
-
-MachOObjectFile::LoadCommandInfo
-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);
-  return Next;
-}
-
 MachO::section MachOObjectFile::getSection(DataRefImpl DRI) const {
+  assert(DRI.d.a < Sections.size() && "Should have detected this earlier");
   return getStruct<MachO::section>(this, Sections[DRI.d.a]);
 }
 
 MachO::section_64 MachOObjectFile::getSection64(DataRefImpl DRI) const {
+  assert(DRI.d.a < Sections.size() && "Should have detected this earlier");
   return getStruct<MachO::section_64>(this, Sections[DRI.d.a]);
 }
 
@@ -1816,9 +2003,9 @@ 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
@@ -1831,6 +2018,80 @@ 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 {
@@ -1857,12 +2118,13 @@ MachOObjectFile::getDice(DataRefImpl Rel) const {
   return getStruct<MachO::data_in_code_entry>(this, P);
 }
 
-MachO::mach_header MachOObjectFile::getHeader() const {
-  return getStruct<MachO::mach_header>(this, getPtr(this, 0));
+const MachO::mach_header &MachOObjectFile::getHeader() const {
+  return Header;
 }
 
-MachO::mach_header_64 MachOObjectFile::getHeader64() const {
-  return getStruct<MachO::mach_header_64>(this, getPtr(this, 0));
+const MachO::mach_header_64 &MachOObjectFile::getHeader64() const {
+  assert(is64Bit());
+  return Header64;
 }
 
 uint32_t MachOObjectFile::getIndirectSymbolTableEntry(
@@ -1880,11 +2142,47 @@ 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
@@ -1901,6 +2199,84 @@ 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);
@@ -1908,7 +2284,7 @@ StringRef MachOObjectFile::getStringTableData() const {
 
 bool MachOObjectFile::is64Bit() const {
   return getType() == getMachOType(false, true) ||
-         getType() == getMachOType(true, true);
+    getType() == getMachOType(true, true);
 }
 
 void MachOObjectFile::ReadULEB128s(uint64_t Index,
@@ -1923,30 +2299,28 @@ void MachOObjectFile::ReadULEB128s(uint64_t Index,
   }
 }
 
-const char *MachOObjectFile::getSectionPointer(DataRefImpl Rel) const {
-  return Sections[Rel.d.a];
+bool MachOObjectFile::isRelocatableObject() const {
+  return getHeader().filetype == MachO::MH_OBJECT;
 }
 
-ErrorOr<ObjectFile *>
-ObjectFile::createMachOObjectFile(std::unique_ptr<MemoryBuffer> &Buffer) {
-  StringRef Magic = Buffer->getBuffer().slice(0, 4);
+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(std::move(Buffer), false, false, EC));
+    Ret.reset(new MachOObjectFile(Buffer, false, false, EC));
   else if (Magic == "\xCE\xFA\xED\xFE")
-    Ret.reset(new MachOObjectFile(std::move(Buffer), true, false, EC));
+    Ret.reset(new MachOObjectFile(Buffer, true, false, EC));
   else if (Magic == "\xFE\xED\xFA\xCF")
-    Ret.reset(new MachOObjectFile(std::move(Buffer), false, true, EC));
+    Ret.reset(new MachOObjectFile(Buffer, false, true, EC));
   else if (Magic == "\xCF\xFA\xED\xFE")
-    Ret.reset(new MachOObjectFile(std::move(Buffer), true, true, EC));
+    Ret.reset(new MachOObjectFile(Buffer, true, true, EC));
   else
     return object_error::parse_failed;
 
   if (EC)
     return EC;
-  return Ret.release();
+  return std::move(Ret);
 }
 
-} // end namespace object
-} // end namespace llvm