[RuntimeDyld] Handle endiannes differences between the host and target while
[oota-llvm.git] / lib / ExecutionEngine / RuntimeDyld / RuntimeDyldMachO.cpp
index 1318b4454255224b8dc73c77f7f326018cd139db..e07c5dfeee5a674673f71e0dd943e552cbfe830e 100644 (file)
 //
 //===----------------------------------------------------------------------===//
 
-#define DEBUG_TYPE "dyld"
-#include "llvm/ADT/OwningPtr.h"
-#include "llvm/ADT/StringRef.h"
-#include "llvm/ADT/STLExtras.h"
 #include "RuntimeDyldMachO.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/StringRef.h"
+#include "ObjectImageCommon.h"
+#include "JITRegistrar.h"
 using namespace llvm;
 using namespace llvm::object;
 
+#define DEBUG_TYPE "dyld"
+
 namespace llvm {
 
-void RuntimeDyldMachO::resolveRelocation(uint8_t *LocalAddress,
-                                         uint64_t FinalAddress,
-                                         uint64_t Value,
-                                         uint32_t Type,
-                                         int64_t Addend) {
-  bool isPCRel = (Type >> 24) & 1;
-  unsigned MachoType = (Type >> 28) & 0xf;
-  unsigned Size = 1 << ((Type >> 25) & 3);
-
-  DEBUG(dbgs() << "resolveRelocation LocalAddress: " << format("%p", LocalAddress)
-        << " FinalAddress: " << format("%p", FinalAddress)
-        << " Value: " << format("%p", Value)
-        << " Addend: " << Addend
-        << " isPCRel: " << isPCRel
-        << " MachoType: " << MachoType
-        << " Size: " << Size
-        << "\n");
+class MachOObjectImage : public ObjectImageCommon {
+private:
+  typedef SmallVector<uint64_t, 1> SectionAddrList;
+  SectionAddrList OldSectionAddrList;
+
+protected:
+  bool is64;
+  bool Registered;
+
+private:
+  void initOldAddress() {
+    MachOObjectFile *objf = static_cast<MachOObjectFile *>(ObjFile.get());
+    // Unfortunately we need to do this, since there's information encoded
+    // in the original addr of the section that we could not otherwise
+    // recover. The reason for this is that symbols do not actually store
+    // their file offset, but only their vmaddr. This means that in order
+    // to locate the symbol correctly in the object file, we need to know
+    // where the original start of the section was (including any padding,
+    // etc).
+    for (section_iterator i = objf->section_begin(), e = objf->section_end();
+         i != e; ++i) {
+      uint64_t Addr;
+      i->getAddress(Addr);
+      OldSectionAddrList[i->getRawDataRefImpl().d.a] = Addr;
+    }
+  }
+
+public:
+  MachOObjectImage(ObjectBuffer *Input, bool is64)
+      : ObjectImageCommon(Input),
+        OldSectionAddrList(ObjFile->section_end()->getRawDataRefImpl().d.a, 0),
+        is64(is64), Registered(false) {
+    initOldAddress();
+  }
+
+  MachOObjectImage(std::unique_ptr<object::ObjectFile> Input, bool is64)
+      : ObjectImageCommon(std::move(Input)),
+        OldSectionAddrList(ObjFile->section_end()->getRawDataRefImpl().d.a, 0),
+        is64(is64), Registered(false) {
+    initOldAddress();
+  }
+
+  virtual ~MachOObjectImage() {
+    if (Registered)
+      deregisterWithDebugger();
+  }
+
+  // Subclasses can override these methods to update the image with loaded
+  // addresses for sections and common symbols
+  virtual void updateSectionAddress(const SectionRef &Sec, uint64_t Addr) {
+    MachOObjectFile *objf = static_cast<MachOObjectFile *>(ObjFile.get());
+    char *data =
+        const_cast<char *>(objf->getSectionPointer(Sec.getRawDataRefImpl()));
+
+    uint64_t oldAddr = OldSectionAddrList[Sec.getRawDataRefImpl().d.a];
+
+    if (is64) {
+      ((MachO::section_64 *)data)->addr = Addr;
+    } else {
+      ((MachO::section *)data)->addr = Addr;
+    }
+
+    for (symbol_iterator i = objf->symbol_begin(), e = objf->symbol_end();
+         i != e; ++i) {
+      section_iterator symSec(objf->section_end());
+      (*i).getSection(symSec);
+      if (*symSec == Sec) {
+        uint64_t symAddr;
+        (*i).getAddress(symAddr);
+        updateSymbolAddress(*i, symAddr + Addr - oldAddr);
+      }
+    }
+  }
+
+  uint64_t getOldSectionAddr(const SectionRef &Sec) const {
+    return OldSectionAddrList[Sec.getRawDataRefImpl().d.a];
+  }
+
+  virtual void updateSymbolAddress(const SymbolRef &Sym, uint64_t Addr) {
+    char *data = const_cast<char *>(
+        reinterpret_cast<const char *>(Sym.getRawDataRefImpl().p));
+    if (is64)
+      ((MachO::nlist_64 *)data)->n_value = Addr;
+    else
+      ((MachO::nlist *)data)->n_value = Addr;
+  }
+
+  virtual void registerWithDebugger() {
+    JITRegistrar::getGDBRegistrar().registerObject(*Buffer);
+    Registered = true;
+  }
+
+  virtual void deregisterWithDebugger() {
+    JITRegistrar::getGDBRegistrar().deregisterObject(*Buffer);
+  }
+};
+
+static uint32_t readMachOMagic(const char *InputBuffer, unsigned BufferSize) {
+  if (BufferSize < 4)
+    return 0;
+  StringRef Magic(InputBuffer, 4);
+  if (Magic == "\xFE\xED\xFA\xCE" || Magic == "\xCE\xFA\xED\xFE")
+    return 0xFEEDFACE;
+  else if (Magic == "\xFE\xED\xFA\xCF" || Magic == "\xCF\xFA\xED\xFE")
+    return 0xFEEDFACF;
+  // else
+  return 0;
+}
+
+ObjectImage *RuntimeDyldMachO::createObjectImage(ObjectBuffer *Buffer) {
+  uint32_t magic = readMachOMagic(Buffer->getBufferStart(),
+                                  Buffer->getBufferSize());
+  bool is64 = (magic == MachO::MH_MAGIC_64);
+  assert((magic == MachO::MH_MAGIC_64 || magic == MachO::MH_MAGIC) &&
+         "Unrecognized Macho Magic");
+  return new MachOObjectImage(Buffer, is64);
+}
+
+ObjectImage *RuntimeDyldMachO::createObjectImageFromFile(
+    std::unique_ptr<object::ObjectFile> ObjFile) {
+  if (!ObjFile)
+    return nullptr;
+
+  MemoryBuffer *Buffer =
+      MemoryBuffer::getMemBuffer(ObjFile->getData(), "", false);
+
+  uint32_t magic = readMachOMagic(Buffer->getBufferStart(),
+                                  Buffer->getBufferSize());
+  bool is64 = (magic == MachO::MH_MAGIC_64);
+  assert((magic == MachO::MH_MAGIC_64 || magic == MachO::MH_MAGIC) &&
+         "Unrecognized Macho Magic");
+  return new MachOObjectImage(std::move(ObjFile), is64);
+}
+
+static unsigned char *processFDE(unsigned char *P, intptr_t DeltaForText,
+                                 intptr_t DeltaForEH) {
+  DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
+               << ", Delta for EH: " << DeltaForEH << "\n");
+  uint32_t Length = *((uint32_t *)P);
+  P += 4;
+  unsigned char *Ret = P + Length;
+  uint32_t Offset = *((uint32_t *)P);
+  if (Offset == 0) // is a CIE
+    return Ret;
+
+  P += 4;
+  intptr_t FDELocation = *((intptr_t *)P);
+  intptr_t NewLocation = FDELocation - DeltaForText;
+  *((intptr_t *)P) = NewLocation;
+  P += sizeof(intptr_t);
+
+  // Skip the FDE address range
+  P += sizeof(intptr_t);
+
+  uint8_t Augmentationsize = *P;
+  P += 1;
+  if (Augmentationsize != 0) {
+    intptr_t LSDA = *((intptr_t *)P);
+    intptr_t NewLSDA = LSDA - DeltaForEH;
+    *((intptr_t *)P) = NewLSDA;
+  }
+
+  return Ret;
+}
+
+static intptr_t computeDelta(SectionEntry *A, SectionEntry *B) {
+  intptr_t ObjDistance = A->ObjAddress - B->ObjAddress;
+  intptr_t MemDistance = A->LoadAddress - B->LoadAddress;
+  return ObjDistance - MemDistance;
+}
+
+void RuntimeDyldMachO::registerEHFrames() {
+
+  if (!MemMgr)
+    return;
+  for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
+    EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
+    if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
+        SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
+      continue;
+    SectionEntry *Text = &Sections[SectionInfo.TextSID];
+    SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
+    SectionEntry *ExceptTab = nullptr;
+    if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
+      ExceptTab = &Sections[SectionInfo.ExceptTabSID];
+
+    intptr_t DeltaForText = computeDelta(Text, EHFrame);
+    intptr_t DeltaForEH = 0;
+    if (ExceptTab)
+      DeltaForEH = computeDelta(ExceptTab, EHFrame);
+
+    unsigned char *P = EHFrame->Address;
+    unsigned char *End = P + EHFrame->Size;
+    do {
+      P = processFDE(P, DeltaForText, DeltaForEH);
+    } while (P != End);
+
+    MemMgr->registerEHFrames(EHFrame->Address, EHFrame->LoadAddress,
+                             EHFrame->Size);
+  }
+  UnregisteredEHFrameSections.clear();
+}
+
+void RuntimeDyldMachO::finalizeLoad(ObjectImage &ObjImg,
+                                    ObjSectionToIDMap &SectionMap) {
+  unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
+  unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
+  unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
+  ObjSectionToIDMap::iterator i, e;
+  for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) {
+    const SectionRef &Section = i->first;
+    StringRef Name;
+    Section.getName(Name);
+    if (Name == "__eh_frame")
+      EHFrameSID = i->second;
+    else if (Name == "__text")
+      TextSID = i->second;
+    else if (Name == "__gcc_except_tab")
+      ExceptTabSID = i->second;
+    else if (Name == "__jump_table")
+      populateJumpTable(cast<MachOObjectFile>(*ObjImg.getObjectFile()),
+                        Section, i->second);
+    else if (Name == "__pointers")
+      populatePointersSection(cast<MachOObjectFile>(*ObjImg.getObjectFile()),
+                              Section, i->second);
+  }
+  UnregisteredEHFrameSections.push_back(
+      EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
+}
+
+// The target location for the relocation is described by RE.SectionID and
+// RE.Offset.  RE.SectionID can be used to find the SectionEntry.  Each
+// SectionEntry has three members describing its location.
+// SectionEntry::Address is the address at which the section has been loaded
+// into memory in the current (host) process.  SectionEntry::LoadAddress is the
+// address that the section will have in the target process.
+// SectionEntry::ObjAddress is the address of the bits for this section in the
+// original emitted object image (also in the current address space).
+//
+// Relocations will be applied as if the section were loaded at
+// SectionEntry::LoadAddress, but they will be applied at an address based
+// on SectionEntry::Address.  SectionEntry::ObjAddress will be used to refer to
+// Target memory contents if they are required for value calculations.
+//
+// The Value parameter here is the load address of the symbol for the
+// relocation to be applied.  For relocations which refer to symbols in the
+// current object Value will be the LoadAddress of the section in which
+// the symbol resides (RE.Addend provides additional information about the
+// symbol location).  For external symbols, Value will be the address of the
+// symbol in the target address space.
+void RuntimeDyldMachO::resolveRelocation(const RelocationEntry &RE,
+                                         uint64_t Value) {
+  DEBUG (
+    const SectionEntry &Section = Sections[RE.SectionID];
+    uint8_t* LocalAddress = Section.Address + RE.Offset;
+    uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
+
+    dbgs() << "resolveRelocation Section: " << RE.SectionID
+           << " LocalAddress: " << format("%p", LocalAddress)
+           << " FinalAddress: " << format("%p", FinalAddress)
+           << " Value: " << format("%p", Value)
+           << " Addend: " << RE.Addend
+           << " isPCRel: " << RE.IsPCRel
+           << " MachoType: " << RE.RelType
+           << " Size: " << (1 << RE.Size) << "\n";
+  );
 
   // This just dispatches to the proper target specific routine.
   switch (Arch) {
-  default: llvm_unreachable("Unsupported CPU type!");
+  default:
+    llvm_unreachable("Unsupported CPU type!");
   case Triple::x86_64:
-    resolveX86_64Relocation(LocalAddress,
-                            FinalAddress,
-                            (uintptr_t)Value,
-                            isPCRel,
-                            MachoType,
-                            Size,
-                            Addend);
+    resolveX86_64Relocation(RE, Value);
     break;
   case Triple::x86:
-    resolveI386Relocation(LocalAddress,
-                                 FinalAddress,
-                                 (uintptr_t)Value,
-                                 isPCRel,
-                                 Type,
-                                 Size,
-                                 Addend);
+    resolveI386Relocation(RE, Value);
     break;
-  case Triple::arm:    // Fall through.
+  case Triple::arm: // Fall through.
   case Triple::thumb:
-    resolveARMRelocation(LocalAddress,
-                         FinalAddress,
-                         (uintptr_t)Value,
-                         isPCRel,
-                         MachoType,
-                         Size,
-                         Addend);
+    resolveARMRelocation(RE, Value);
+    break;
+  case Triple::aarch64:
+  case Triple::arm64:
+    resolveAArch64Relocation(RE, Value);
     break;
   }
 }
 
-bool RuntimeDyldMachO::
-resolveI386Relocation(uint8_t *LocalAddress,
-                      uint64_t FinalAddress,
-                      uint64_t Value,
-                      bool isPCRel,
-                      unsigned Type,
-                      unsigned Size,
-                      int64_t Addend) {
-  if (isPCRel)
-    Value -= FinalAddress + 4; // see resolveX86_64Relocation
-
-  switch (Type) {
-  default:
-    llvm_unreachable("Invalid relocation type!");
-  case macho::RIT_Vanilla: {
-    uint8_t *p = LocalAddress;
-    uint64_t ValueToWrite = Value + Addend;
-    for (unsigned i = 0; i < Size; ++i) {
-      *p++ = (uint8_t)(ValueToWrite & 0xff);
-      ValueToWrite >>= 8;
-    }
+bool RuntimeDyldMachO::resolveI386Relocation(const RelocationEntry &RE,
+                                             uint64_t Value) {
+  const SectionEntry &Section = Sections[RE.SectionID];
+  uint8_t* LocalAddress = Section.Address + RE.Offset;
+
+  if (RE.IsPCRel) {
+    uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
+    Value -= FinalAddress + 4; // see MachOX86_64::resolveRelocation.
   }
-  case macho::RIT_Difference:
-  case macho::RIT_Generic_LocalDifference:
-  case macho::RIT_Generic_PreboundLazyPointer:
-    return Error("Relocation type not implemented yet!");
+
+  switch (RE.RelType) {
+    default:
+      llvm_unreachable("Invalid relocation type!");
+    case MachO::GENERIC_RELOC_VANILLA:
+      return applyRelocationValue(LocalAddress, Value + RE.Addend,
+                                  1 << RE.Size);
+    case MachO::GENERIC_RELOC_SECTDIFF:
+    case MachO::GENERIC_RELOC_LOCAL_SECTDIFF: {
+      uint64_t SectionABase = Sections[RE.Sections.SectionA].LoadAddress;
+      uint64_t SectionBBase = Sections[RE.Sections.SectionB].LoadAddress;
+      assert((Value == SectionABase || Value == SectionBBase) &&
+             "Unexpected SECTDIFF relocation value.");
+      Value = SectionABase - SectionBBase + RE.Addend;
+      return applyRelocationValue(LocalAddress, Value, 1 << RE.Size);
+    }
+    case MachO::GENERIC_RELOC_PB_LA_PTR:
+      return Error("Relocation type not implemented yet!");
   }
 }
 
-bool RuntimeDyldMachO::
-resolveX86_64Relocation(uint8_t *LocalAddress,
-                        uint64_t FinalAddress,
-                        uint64_t Value,
-                        bool isPCRel,
-                        unsigned Type,
-                        unsigned Size,
-                        int64_t Addend) {
+bool RuntimeDyldMachO::resolveX86_64Relocation(const RelocationEntry &RE,
+                                               uint64_t Value) {
+  const SectionEntry &Section = Sections[RE.SectionID];
+  uint8_t* LocalAddress = Section.Address + RE.Offset;
+
   // If the relocation is PC-relative, the value to be encoded is the
   // pointer difference.
-  if (isPCRel)
+  if (RE.IsPCRel) {
     // FIXME: It seems this value needs to be adjusted by 4 for an effective PC
     // address. Is that expected? Only for branches, perhaps?
-    Value -= FinalAddress + 4;
+    uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
+    Value -= FinalAddress + 4; // see MachOX86_64::resolveRelocation.
+  }
 
-  switch(Type) {
+  switch (RE.RelType) {
   default:
     llvm_unreachable("Invalid relocation type!");
-  case macho::RIT_X86_64_Signed1:
-  case macho::RIT_X86_64_Signed2:
-  case macho::RIT_X86_64_Signed4:
-  case macho::RIT_X86_64_Signed:
-  case macho::RIT_X86_64_Unsigned:
-  case macho::RIT_X86_64_Branch: {
-    Value += Addend;
-    // Mask in the target value a byte at a time (we don't have an alignment
-    // guarantee for the target address, so this is safest).
-    uint8_t *p = (uint8_t*)LocalAddress;
-    for (unsigned i = 0; i < Size; ++i) {
-      *p++ = (uint8_t)Value;
-      Value >>= 8;
-    }
-    return false;
-  }
-  case macho::RIT_X86_64_GOTLoad:
-  case macho::RIT_X86_64_GOT:
-  case macho::RIT_X86_64_Subtractor:
-  case macho::RIT_X86_64_TLV:
+  case MachO::X86_64_RELOC_SIGNED_1:
+  case MachO::X86_64_RELOC_SIGNED_2:
+  case MachO::X86_64_RELOC_SIGNED_4:
+  case MachO::X86_64_RELOC_SIGNED:
+  case MachO::X86_64_RELOC_UNSIGNED:
+  case MachO::X86_64_RELOC_BRANCH:
+    return applyRelocationValue(LocalAddress, Value + RE.Addend, 1 << RE.Size);
+  case MachO::X86_64_RELOC_GOT_LOAD:
+  case MachO::X86_64_RELOC_GOT:
+  case MachO::X86_64_RELOC_SUBTRACTOR:
+  case MachO::X86_64_RELOC_TLV:
     return Error("Relocation type not implemented yet!");
   }
 }
 
-bool RuntimeDyldMachO::
-resolveARMRelocation(uint8_t *LocalAddress,
-                     uint64_t FinalAddress,
-                     uint64_t Value,
-                     bool isPCRel,
-                     unsigned Type,
-                     unsigned Size,
-                     int64_t Addend) {
+bool RuntimeDyldMachO::resolveARMRelocation(const RelocationEntry &RE,
+                                            uint64_t Value) {
+  const SectionEntry &Section = Sections[RE.SectionID];
+  uint8_t* LocalAddress = Section.Address + RE.Offset;
+
   // If the relocation is PC-relative, the value to be encoded is the
   // pointer difference.
-  if (isPCRel) {
+  if (RE.IsPCRel) {
+    uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
     Value -= FinalAddress;
     // ARM PCRel relocations have an effective-PC offset of two instructions
     // (four bytes in Thumb mode, 8 bytes in ARM mode).
@@ -162,132 +389,593 @@ resolveARMRelocation(uint8_t *LocalAddress,
     Value -= 8;
   }
 
-  switch(Type) {
+  switch (RE.RelType) {
   default:
     llvm_unreachable("Invalid relocation type!");
-  case macho::RIT_Vanilla: {
-    // Mask in the target value a byte at a time (we don't have an alignment
-    // guarantee for the target address, so this is safest).
-    uint8_t *p = (uint8_t*)LocalAddress;
-    for (unsigned i = 0; i < Size; ++i) {
-      *p++ = (uint8_t)Value;
-      Value >>= 8;
-    }
-    break;
-  }
-  case macho::RIT_ARM_Branch24Bit: {
+  case MachO::ARM_RELOC_VANILLA:
+    return applyRelocationValue(LocalAddress, Value, 1 << RE.Size);
+  case MachO::ARM_RELOC_BR24: {
     // Mask the value into the target address. We know instructions are
     // 32-bit aligned, so we can do it all at once.
-    uint32_t *p = (uint32_t*)LocalAddress;
+    uint32_t *p = (uint32_t *)LocalAddress;
     // The low two bits of the value are not encoded.
     Value >>= 2;
     // Mask the value to 24 bits.
-    Value &= 0xffffff;
+    uint64_t FinalValue = Value & 0xffffff;
+    // Check for overflow.
+    if (Value != FinalValue)
+      return Error("ARM BR24 relocation out of range.");
     // FIXME: If the destination is a Thumb function (and the instruction
     // is a non-predicated BL instruction), we need to change it to a BLX
     // instruction instead.
 
     // Insert the value into the instruction.
-    *p = (*p & ~0xffffff) | Value;
+    *p = (*p & ~0xffffff) | FinalValue;
+    break;
+  }
+  case MachO::ARM_THUMB_RELOC_BR22:
+  case MachO::ARM_THUMB_32BIT_BRANCH:
+  case MachO::ARM_RELOC_HALF:
+  case MachO::ARM_RELOC_HALF_SECTDIFF:
+  case MachO::ARM_RELOC_PAIR:
+  case MachO::ARM_RELOC_SECTDIFF:
+  case MachO::ARM_RELOC_LOCAL_SECTDIFF:
+  case MachO::ARM_RELOC_PB_LA_PTR:
+    return Error("Relocation type not implemented yet!");
+  }
+  return false;
+}
+
+bool RuntimeDyldMachO::resolveAArch64Relocation(const RelocationEntry &RE,
+                                                uint64_t Value) {
+  const SectionEntry &Section = Sections[RE.SectionID];
+  uint8_t* LocalAddress = Section.Address + RE.Offset;
+
+  switch (RE.RelType) {
+  default:
+    llvm_unreachable("Invalid relocation type!");
+  case MachO::ARM64_RELOC_UNSIGNED: {
+    assert(!RE.IsPCRel && "PCRel and ARM64_RELOC_UNSIGNED not supported");
+    // Mask in the target value a byte at a time (we don't have an alignment
+    // guarantee for the target address, so this is safest).
+    if (RE.Size < 2)
+      llvm_unreachable("Invalid size for ARM64_RELOC_UNSIGNED");
+
+    applyRelocationValue(LocalAddress, Value + RE.Addend, 1 << RE.Size);
+    break;
+  }
+  case MachO::ARM64_RELOC_BRANCH26: {
+    assert(RE.IsPCRel && "not PCRel and ARM64_RELOC_BRANCH26 not supported");
+    // Mask the value into the target address. We know instructions are
+    // 32-bit aligned, so we can do it all at once.
+    uint32_t *p = (uint32_t*)LocalAddress;
+    // Check if the addend is encoded in the instruction.
+    uint32_t EncodedAddend = *p & 0x03FFFFFF;
+    if (EncodedAddend != 0 ) {
+      if (RE.Addend == 0)
+        llvm_unreachable("branch26 instruction has embedded addend.");
+      else
+        llvm_unreachable("branch26 instruction has embedded addend and" \
+                         "ARM64_RELOC_ADDEND.");
+    }
+    // Check if branch is in range.
+    uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
+    uint64_t PCRelVal = Value - FinalAddress + RE.Addend;
+    assert(isInt<26>(PCRelVal) && "Branch target out of range!");
+    // Insert the value into the instruction.
+    *p = (*p & 0xFC000000) | ((uint32_t)(PCRelVal >> 2) & 0x03FFFFFF);
+    break;
+  }
+  case MachO::ARM64_RELOC_GOT_LOAD_PAGE21:
+  case MachO::ARM64_RELOC_PAGE21: {
+    assert(RE.IsPCRel && "not PCRel and ARM64_RELOC_PAGE21 not supported");
+    // Mask the value into the target address. We know instructions are
+    // 32-bit aligned, so we can do it all at once.
+    uint32_t *p = (uint32_t*)LocalAddress;
+    // Check if the addend is encoded in the instruction.
+    uint32_t EncodedAddend = ((*p & 0x60000000) >> 29) |
+                             ((*p & 0x01FFFFE0) >> 3);
+    if (EncodedAddend != 0) {
+      if (RE.Addend == 0)
+        llvm_unreachable("adrp instruction has embedded addend.");
+      else
+        llvm_unreachable("adrp instruction has embedded addend and" \
+                         "ARM64_RELOC_ADDEND.");
+    }
+    // Adjust for PC-relative relocation and offset.
+    uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
+    uint64_t PCRelVal = ((Value + RE.Addend) & (-4096)) -
+                         (FinalAddress & (-4096));
+    // Check that the value fits into 21 bits (+ 12 lower bits).
+    assert(isInt<33>(PCRelVal) && "Invalid page reloc value!");
+    // Insert the value into the instruction.
+    uint32_t ImmLoValue = (uint32_t)(PCRelVal << 17) & 0x60000000;
+    uint32_t ImmHiValue = (uint32_t)(PCRelVal >>  9) & 0x00FFFFE0;
+    *p = (*p & 0x9F00001F) | ImmHiValue | ImmLoValue;
+    break;
+  }
+  case MachO::ARM64_RELOC_GOT_LOAD_PAGEOFF12:
+  case MachO::ARM64_RELOC_PAGEOFF12: {
+    assert(!RE.IsPCRel && "PCRel and ARM64_RELOC_PAGEOFF21 not supported");
+    // Mask the value into the target address. We know instructions are
+    // 32-bit aligned, so we can do it all at once.
+    uint32_t *p = (uint32_t*)LocalAddress;
+    // Check if the addend is encoded in the instruction.
+    uint32_t EncodedAddend = *p & 0x003FFC00;
+    if (EncodedAddend != 0) {
+      if (RE.Addend == 0)
+        llvm_unreachable("adrp instruction has embedded addend.");
+      else
+        llvm_unreachable("adrp instruction has embedded addend and" \
+                         "ARM64_RELOC_ADDEND.");
+    }
+    // Add the offset from the symbol.
+    Value += RE.Addend;
+    // Mask out the page address and only use the lower 12 bits.
+    Value &= 0xFFF;
+    // Check which instruction we are updating to obtain the implicit shift
+    // factor from LDR/STR instructions.
+    if (*p & 0x08000000) {
+      uint32_t ImplicitShift = ((*p >> 30) & 0x3);
+      switch (ImplicitShift) {
+      case 0:
+        // Check if this a vector op.
+        if ((*p & 0x04800000) == 0x04800000) {
+          ImplicitShift = 4;
+          assert(((Value & 0xF) == 0) &&
+                 "128-bit LDR/STR not 16-byte aligned.");
+        }
+        break;
+      case 1:
+        assert(((Value & 0x1) == 0) && "16-bit LDR/STR not 2-byte aligned.");
+      case 2:
+        assert(((Value & 0x3) == 0) && "32-bit LDR/STR not 4-byte aligned.");
+      case 3:
+        assert(((Value & 0x7) == 0) && "64-bit LDR/STR not 8-byte aligned.");
+      }
+      // Compensate for implicit shift.
+      Value >>= ImplicitShift;
+    }
+    // Insert the value into the instruction.
+    *p = (*p & 0xFFC003FF) | ((uint32_t)(Value << 10) & 0x003FFC00);
     break;
   }
-  case macho::RIT_ARM_ThumbBranch22Bit:
-  case macho::RIT_ARM_ThumbBranch32Bit:
-  case macho::RIT_ARM_Half:
-  case macho::RIT_ARM_HalfDifference:
-  case macho::RIT_Pair:
-  case macho::RIT_Difference:
-  case macho::RIT_ARM_LocalDifference:
-  case macho::RIT_ARM_PreboundLazyPointer:
+  case MachO::ARM64_RELOC_SUBTRACTOR:
+  case MachO::ARM64_RELOC_POINTER_TO_GOT:
+  case MachO::ARM64_RELOC_TLVP_LOAD_PAGE21:
+  case MachO::ARM64_RELOC_TLVP_LOAD_PAGEOFF12:
+    llvm_unreachable("Relocation type not implemented yet!");
     return Error("Relocation type not implemented yet!");
+  case MachO::ARM64_RELOC_ADDEND:
+    llvm_unreachable("ARM64_RELOC_ADDEND should have been handeled by " \
+                     "processRelocationRef!");
   }
   return false;
 }
 
-void RuntimeDyldMachO::processRelocationRef(const ObjRelocationInfo &Rel,
-                                            const ObjectFile &Obj,
-                                            ObjSectionToIDMap &ObjSectionToID,
-                                            LocalSymbolMap &Symbols,
-                                            StubMap &Stubs) {
+void RuntimeDyldMachO::populateJumpTable(MachOObjectFile &Obj,
+                                         const SectionRef &JTSection,
+                                         unsigned JTSectionID) {
+  assert(!Obj.is64Bit() &&
+         "__jump_table section not supported in 64-bit MachO.");
+
+  MachO::dysymtab_command DySymTabCmd = Obj.getDysymtabLoadCommand();
+  MachO::section Sec32 = Obj.getSection(JTSection.getRawDataRefImpl());
+  uint32_t JTSectionSize = Sec32.size;
+  unsigned FirstIndirectSymbol = Sec32.reserved1;
+  unsigned JTEntrySize = Sec32.reserved2;
+  unsigned NumJTEntries = JTSectionSize / JTEntrySize;
+  uint8_t* JTSectionAddr = getSectionAddress(JTSectionID);
+  unsigned JTEntryOffset = 0;
+
+  assert((JTSectionSize % JTEntrySize) == 0 &&
+         "Jump-table section does not contain a whole number of stubs?");
+
+  for (unsigned i = 0; i < NumJTEntries; ++i) {
+    unsigned SymbolIndex =
+      Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
+    symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
+    StringRef IndirectSymbolName;
+    SI->getName(IndirectSymbolName);
+    uint8_t* JTEntryAddr = JTSectionAddr + JTEntryOffset;
+    createStubFunction(JTEntryAddr);
+    RelocationEntry RE(JTSectionID, JTEntryOffset + 1,
+                       MachO::GENERIC_RELOC_VANILLA, 0, true, 2);
+    addRelocationForSymbol(RE, IndirectSymbolName);
+    JTEntryOffset += JTEntrySize;
+  }
+}
+
+void RuntimeDyldMachO::populatePointersSection(MachOObjectFile &Obj,
+                                               const SectionRef &PTSection,
+                                               unsigned PTSectionID) {
+  assert(!Obj.is64Bit() &&
+         "__pointers section not supported in 64-bit MachO.");
+
+  MachO::dysymtab_command DySymTabCmd = Obj.getDysymtabLoadCommand();
+  MachO::section Sec32 = Obj.getSection(PTSection.getRawDataRefImpl());
+  uint32_t PTSectionSize = Sec32.size;
+  unsigned FirstIndirectSymbol = Sec32.reserved1;
+  const unsigned PTEntrySize = 4;
+  unsigned NumPTEntries = PTSectionSize / PTEntrySize;
+  unsigned PTEntryOffset = 0;
+
+  assert((PTSectionSize % PTEntrySize) == 0 &&
+         "Pointers section does not contain a whole number of stubs?");
+
+  DEBUG(dbgs() << "Populating __pointers, Section ID " << PTSectionID
+               << ", " << NumPTEntries << " entries, "
+               << PTEntrySize << " bytes each:\n");
+
+  for (unsigned i = 0; i < NumPTEntries; ++i) {
+    unsigned SymbolIndex =
+      Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
+    symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
+    StringRef IndirectSymbolName;
+    SI->getName(IndirectSymbolName);
+    DEBUG(dbgs() << "  " << IndirectSymbolName << ": index " << SymbolIndex
+          << ", PT offset: " << PTEntryOffset << "\n");
+    RelocationEntry RE(PTSectionID, PTEntryOffset,
+                       MachO::GENERIC_RELOC_VANILLA, 0, false, 2);
+    addRelocationForSymbol(RE, IndirectSymbolName);
+    PTEntryOffset += PTEntrySize;
+  }
+}
+
+
+section_iterator getSectionByAddress(const MachOObjectFile &Obj,
+                                     uint64_t Addr) {
+  section_iterator SI = Obj.section_begin();
+  section_iterator SE = Obj.section_end();
+
+  for (; SI != SE; ++SI) {
+    uint64_t SAddr, SSize;
+    SI->getAddress(SAddr);
+    SI->getSize(SSize);
+    if ((Addr >= SAddr) && (Addr < SAddr + SSize))
+      return SI;
+  }
+
+  return SE;
+}
+
+relocation_iterator RuntimeDyldMachO::processSECTDIFFRelocation(
+                                            unsigned SectionID,
+                                            relocation_iterator RelI,
+                                            ObjectImage &Obj,
+                                            ObjSectionToIDMap &ObjSectionToID) {
+  const MachOObjectFile *MachO =
+    static_cast<const MachOObjectFile*>(Obj.getObjectFile());
+  MachO::any_relocation_info RE =
+    MachO->getRelocation(RelI->getRawDataRefImpl());
+
+  SectionEntry &Section = Sections[SectionID];
+  uint32_t RelocType = MachO->getAnyRelocationType(RE);
+  bool IsPCRel = MachO->getAnyRelocationPCRel(RE);
+  unsigned Size = MachO->getAnyRelocationLength(RE);
+  uint64_t Offset;
+  RelI->getOffset(Offset);
+  uint8_t *LocalAddress = Section.Address + Offset;
+  unsigned NumBytes = 1 << Size;
+  int64_t Addend = 0;
+  memcpy(&Addend, LocalAddress, NumBytes);
+
+  ++RelI;
+  MachO::any_relocation_info RE2 =
+    MachO->getRelocation(RelI->getRawDataRefImpl());
+
+  uint32_t AddrA = MachO->getScatteredRelocationValue(RE);
+  section_iterator SAI = getSectionByAddress(*MachO, AddrA);
+  assert(SAI != MachO->section_end() && "Can't find section for address A");
+  uint64_t SectionABase;
+  SAI->getAddress(SectionABase);
+  uint64_t SectionAOffset = AddrA - SectionABase;
+  SectionRef SectionA = *SAI;
+  bool IsCode;
+  SectionA.isText(IsCode);
+  uint32_t SectionAID = findOrEmitSection(Obj, SectionA, IsCode,
+                                          ObjSectionToID);
+
+  uint32_t AddrB = MachO->getScatteredRelocationValue(RE2);
+  section_iterator SBI = getSectionByAddress(*MachO, AddrB);
+  assert(SBI != MachO->section_end() && "Can't find section for address B");
+  uint64_t SectionBBase;
+  SBI->getAddress(SectionBBase);
+  uint64_t SectionBOffset = AddrB - SectionBBase;
+  SectionRef SectionB = *SBI;
+  uint32_t SectionBID = findOrEmitSection(Obj, SectionB, IsCode,
+                                          ObjSectionToID);
+
+  if (Addend != AddrA - AddrB)
+    Error("Unexpected SECTDIFF relocation addend.");
+
+  DEBUG(dbgs() << "Found SECTDIFF: AddrA: " << AddrA << ", AddrB: " << AddrB
+               << ", Addend: " << Addend << ", SectionA ID: "
+               << SectionAID << ", SectionAOffset: " << SectionAOffset
+               << ", SectionB ID: " << SectionBID << ", SectionBOffset: "
+               << SectionBOffset << "\n");
+  RelocationEntry R(SectionID, Offset, RelocType, 0,
+                    SectionAID, SectionAOffset, SectionBID, SectionBOffset,
+                    IsPCRel, Size);
+
+  addRelocationForSection(R, SectionAID);
+  addRelocationForSection(R, SectionBID);
+
+  return ++RelI;
+}
+
+relocation_iterator RuntimeDyldMachO::processI386ScatteredVANILLA(
+                                            unsigned SectionID,
+                                            relocation_iterator RelI,
+                                            ObjectImage &Obj,
+                                            ObjSectionToIDMap &ObjSectionToID) {
+  const MachOObjectFile *MachO =
+    static_cast<const MachOObjectFile*>(Obj.getObjectFile());
+  MachO::any_relocation_info RE =
+    MachO->getRelocation(RelI->getRawDataRefImpl());
+
+  SectionEntry &Section = Sections[SectionID];
+  uint32_t RelocType = MachO->getAnyRelocationType(RE);
+  bool IsPCRel = MachO->getAnyRelocationPCRel(RE);
+  unsigned Size = MachO->getAnyRelocationLength(RE);
+  uint64_t Offset;
+  RelI->getOffset(Offset);
+  uint8_t *LocalAddress = Section.Address + Offset;
+  unsigned NumBytes = 1 << Size;
+  int64_t Addend = 0;
+  memcpy(&Addend, LocalAddress, NumBytes);
+
+  unsigned SymbolBaseAddr = MachO->getScatteredRelocationValue(RE);
+  section_iterator TargetSI = getSectionByAddress(*MachO, SymbolBaseAddr);
+  assert(TargetSI != MachO->section_end() && "Can't find section for symbol");
+  uint64_t SectionBaseAddr;
+  TargetSI->getAddress(SectionBaseAddr);
+  SectionRef TargetSection = *TargetSI;
+  bool IsCode;
+  TargetSection.isText(IsCode);
+  uint32_t TargetSectionID = findOrEmitSection(Obj, TargetSection, IsCode,
+                                               ObjSectionToID);
+
+  Addend -= SectionBaseAddr;
+  RelocationEntry R(SectionID, Offset, RelocType, Addend,
+                    IsPCRel, Size);
+
+  addRelocationForSection(R, TargetSectionID);
+
+  return ++RelI;
+}
+
+relocation_iterator RuntimeDyldMachO::processRelocationRef(
+    unsigned SectionID, relocation_iterator RelI, ObjectImage &Obj,
+    ObjSectionToIDMap &ObjSectionToID, const SymbolTableMap &Symbols,
+    StubMap &Stubs) {
+  const ObjectFile *OF = Obj.getObjectFile();
+  const MachOObjectImage &MachOObj = *static_cast<MachOObjectImage *>(&Obj);
+  const MachOObjectFile *MachO = static_cast<const MachOObjectFile *>(OF);
+  MachO::any_relocation_info RE =
+      MachO->getRelocation(RelI->getRawDataRefImpl());
+  int64_t RelocAddendValue = 0;
+  bool HasRelocAddendValue = false;
+
+  uint32_t RelType = MachO->getAnyRelocationType(RE);
+  if (Arch == Triple::arm64) {
+    // ARM64_RELOC_ADDEND provides the offset (addend) that will be used by the
+    // next relocation entry. Save the value and advance to the next relocation
+    // entry.
+    if (RelType == MachO::ARM64_RELOC_ADDEND) {
+      assert(!MachO->getPlainRelocationExternal(RE));
+      assert(!MachO->getAnyRelocationPCRel(RE));
+      assert(MachO->getAnyRelocationLength(RE) == 2);
+      uint64_t RawAddend = MachO->getPlainRelocationSymbolNum(RE);
+      // Sign-extend the 24-bit to 64-bit.
+      RelocAddendValue = RawAddend << 40;
+      RelocAddendValue >>= 40;
+      HasRelocAddendValue = true;
+
+      // Get the next entry.
+      RE = MachO->getRelocation((++RelI)->getRawDataRefImpl());
+      RelType = MachO->getAnyRelocationType(RE);
+      assert(RelType == MachO::ARM64_RELOC_BRANCH26 ||
+             RelType == MachO::ARM64_RELOC_PAGE21 ||
+             RelType == MachO::ARM64_RELOC_PAGEOFF12);
+
+    } else if (RelType == MachO::ARM64_RELOC_BRANCH26 ||
+               RelType == MachO::ARM64_RELOC_PAGE21 ||
+               RelType == MachO::ARM64_RELOC_PAGEOFF12 ||
+               RelType == MachO::ARM64_RELOC_GOT_LOAD_PAGE21 ||
+               RelType == MachO::ARM64_RELOC_GOT_LOAD_PAGEOFF12) {
+      RelocAddendValue = 0;
+      HasRelocAddendValue = true;
+    }
+  }
+
+  // FIXME: Properly handle scattered relocations.
+  //        Special case the couple of scattered relocations that we know how
+  //        to handle: SECTDIFF relocations, and scattered VANILLA relocations
+  //        on I386.
+  //        For all other scattered relocations, just bail out and hope for the
+  //        best, since the offsets computed by scattered relocations have often
+  //        been optimisticaly filled in by the compiler. This will fail
+  //        horribly where the relocations *do* need to be applied, but that was
+  //        already the case.
+  if (MachO->isRelocationScattered(RE)) {
+    if (RelType == MachO::GENERIC_RELOC_SECTDIFF ||
+        RelType == MachO::GENERIC_RELOC_LOCAL_SECTDIFF)
+      return processSECTDIFFRelocation(SectionID, RelI, Obj, ObjSectionToID);
+    else if (Arch == Triple::x86 && RelType == MachO::GENERIC_RELOC_VANILLA)
+      return processI386ScatteredVANILLA(SectionID, RelI, Obj, ObjSectionToID);
+    else
+      return ++RelI;
+  }
 
-  uint32_t RelType = (uint32_t) (Rel.Type & 0xffffffffL);
   RelocationValueRef Value;
-  SectionEntry &Section = Sections[Rel.SectionID];
-  uint8_t *Target = Section.Address + Rel.Offset;
+  SectionEntry &Section = Sections[SectionID];
+
+  bool IsExtern = MachO->getPlainRelocationExternal(RE);
+  bool IsPCRel = MachO->getAnyRelocationPCRel(RE);
+  unsigned Size = MachO->getAnyRelocationLength(RE);
+  uint64_t Offset;
+  RelI->getOffset(Offset);
+  uint8_t *LocalAddress = Section.Address + Offset;
+  unsigned NumBytes = 1 << Size;
+  int64_t Addend = 0;
+  if (HasRelocAddendValue)
+    Addend = RelocAddendValue;
+  else
+    memcpy(&Addend, LocalAddress, NumBytes);
 
-  bool isExtern = (RelType >> 27) & 1;
-  if (isExtern) {
+  if (IsExtern) {
+    // Obtain the symbol name which is referenced in the relocation
+    symbol_iterator Symbol = RelI->getSymbol();
     StringRef TargetName;
-    const SymbolRef &Symbol = Rel.Symbol;
-    Symbol.getName(TargetName);
-    // First look the symbol in object file symbols.
-    LocalSymbolMap::iterator lsi = Symbols.find(TargetName.data());
+    Symbol->getName(TargetName);
+    // First search for the symbol in the local symbol table
+    SymbolTableMap::const_iterator lsi = Symbols.find(TargetName.data());
     if (lsi != Symbols.end()) {
       Value.SectionID = lsi->second.first;
-      Value.Addend = lsi->second.second;
+      Value.Addend = lsi->second.second + Addend;
     } else {
-      // Second look the symbol in global symbol table.
-      StringMap<SymbolLoc>::iterator gsi = SymbolTable.find(TargetName.data());
-      if (gsi != SymbolTable.end()) {
+      // Search for the symbol in the global symbol table
+      SymbolTableMap::const_iterator gsi =
+          GlobalSymbolTable.find(TargetName.data());
+      if (gsi != GlobalSymbolTable.end()) {
         Value.SectionID = gsi->second.first;
-        Value.Addend = gsi->second.second;
-      } else
+        Value.Addend = gsi->second.second + Addend;
+      } else {
         Value.SymbolName = TargetName.data();
+        Value.Addend = Addend;
+      }
     }
-  } else {
-    error_code err;
-    uint8_t sectionIndex = static_cast<uint8_t>(RelType & 0xFF);
-    section_iterator si = Obj.begin_sections(),
-                     se = Obj.end_sections();
-    for (uint8_t i = 1; i < sectionIndex; i++) {
-      error_code err;
-      si.increment(err);
-      if (si == se)
-        break;
-    }
-    assert(si != se && "No section containing relocation!");
-    Value.SectionID = findOrEmitSection(*si, true, ObjSectionToID);
-    Value.Addend = *(const intptr_t *)Target;
-    if (Value.Addend) {
-      // The MachO addend is offset from the current section, we need set it
-      // as offset from destination section
-      Value.Addend += Section.ObjAddress - Sections[Value.SectionID].ObjAddress;
+
+    // Addends for external, PC-rel relocations on i386 point back to the zero
+    // offset. Calculate the final offset from the relocation target instead.
+    // This allows us to use the same logic for both external and internal
+    // relocations in resolveI386RelocationRef.
+    if (Arch == Triple::x86 && IsPCRel) {
+      uint64_t RelocAddr = 0;
+      RelI->getAddress(RelocAddr);
+      Value.Addend += RelocAddr + 4;
     }
+
+  } else {
+    SectionRef Sec = MachO->getRelocationSection(RE);
+    bool IsCode = false;
+    Sec.isText(IsCode);
+    Value.SectionID = findOrEmitSection(Obj, Sec, IsCode, ObjSectionToID);
+    uint64_t Addr = MachOObj.getOldSectionAddr(Sec);
+    DEBUG(dbgs() << "\nAddr: " << Addr << "\nAddend: " << Addend);
+    Value.Addend = Addend - Addr;
+    if (IsPCRel)
+      Value.Addend += Offset + NumBytes;
   }
 
-  if (Arch == Triple::arm && RelType == macho::RIT_ARM_Branch24Bit) {
+  if (Arch == Triple::x86_64 && (RelType == MachO::X86_64_RELOC_GOT ||
+                                 RelType == MachO::X86_64_RELOC_GOT_LOAD)) {
+    assert(IsPCRel);
+    assert(Size == 2);
+
+    // FIXME: Teach the generic code above not to prematurely conflate
+    //        relocation addends and symbol offsets.
+    Value.Addend -= Addend;
+    StubMap::const_iterator i = Stubs.find(Value);
+    uint8_t *Addr;
+    if (i != Stubs.end()) {
+      Addr = Section.Address + i->second;
+    } else {
+      Stubs[Value] = Section.StubOffset;
+      uint8_t *GOTEntry = Section.Address + Section.StubOffset;
+      RelocationEntry GOTRE(SectionID, Section.StubOffset,
+                            MachO::X86_64_RELOC_UNSIGNED, Value.Addend, false,
+                            3);
+      if (Value.SymbolName)
+        addRelocationForSymbol(GOTRE, Value.SymbolName);
+      else
+        addRelocationForSection(GOTRE, Value.SectionID);
+      Section.StubOffset += 8;
+      Addr = GOTEntry;
+    }
+    RelocationEntry TargetRE(SectionID, Offset,
+                             MachO::X86_64_RELOC_UNSIGNED, Addend, true,
+                             2);
+    resolveRelocation(TargetRE, (uint64_t)Addr);
+  } else if (Arch == Triple::arm && (RelType & 0xf) == MachO::ARM_RELOC_BR24) {
     // This is an ARM branch relocation, need to use a stub function.
 
     //  Look up for existing stub.
     StubMap::const_iterator i = Stubs.find(Value);
-    if (i != Stubs.end())
-      resolveRelocation(Target, (uint64_t)Target,
-                        (uint64_t)Section.Address + i->second,
-                        RelType, 0);
-    else {
+    uint8_t *Addr;
+    if (i != Stubs.end()) {
+      Addr = Section.Address + i->second;
+    } else {
       // Create a new stub function.
       Stubs[Value] = Section.StubOffset;
-      uint8_t *StubTargetAddr = createStubFunction(Section.Address +
-                                                   Section.StubOffset);
-      AddRelocation(Value, Rel.SectionID, StubTargetAddr - Section.Address,
-                    macho::RIT_Vanilla);
-      resolveRelocation(Target, (uint64_t)Target,
-                        (uint64_t)Section.Address + Section.StubOffset,
-                        RelType, 0);
+      uint8_t *StubTargetAddr =
+          createStubFunction(Section.Address + Section.StubOffset);
+      RelocationEntry StubRE(SectionID, StubTargetAddr - Section.Address,
+                             MachO::GENERIC_RELOC_VANILLA, Value.Addend);
+      if (Value.SymbolName)
+        addRelocationForSymbol(StubRE, Value.SymbolName);
+      else
+        addRelocationForSection(StubRE, Value.SectionID);
+      Addr = Section.Address + Section.StubOffset;
       Section.StubOffset += getMaxStubSize();
     }
-  } else
-    AddRelocation(Value, Rel.SectionID, Rel.Offset, RelType);
+    RelocationEntry TargetRE(Value.SectionID, Offset, RelType, 0, IsPCRel,
+                             Size);
+    resolveRelocation(TargetRE, (uint64_t)Addr);
+  } else if (Arch == Triple::arm64 &&
+             (RelType == MachO::ARM64_RELOC_GOT_LOAD_PAGE21 ||
+              RelType == MachO::ARM64_RELOC_GOT_LOAD_PAGEOFF12)) {
+    assert(Size == 2);
+    StubMap::const_iterator i = Stubs.find(Value);
+    uint8_t *Addr;
+    if (i != Stubs.end())
+      Addr = Section.Address + i->second;
+    else {
+      // FIXME: There must be a better way to do this then to check and fix the
+      // alignment every time!!!
+      uintptr_t BaseAddress = uintptr_t(Section.Address);
+      uintptr_t StubAlignment = getStubAlignment();
+      uintptr_t StubAddress
+        = (BaseAddress + Section.StubOffset + StubAlignment - 1) &
+          -StubAlignment;
+      unsigned StubOffset = StubAddress - BaseAddress;
+      Stubs[Value] = StubOffset;
+      assert(((StubAddress % getStubAlignment()) == 0) &&
+             "GOT entry not aligned");
+      RelocationEntry GOTRE(SectionID, StubOffset, MachO::ARM64_RELOC_UNSIGNED,
+                            Value.Addend, /*IsPCRel=*/false, /*Size=*/3);
+      if (Value.SymbolName)
+        addRelocationForSymbol(GOTRE, Value.SymbolName);
+      else
+        addRelocationForSection(GOTRE, Value.SectionID);
+      Section.StubOffset = StubOffset + getMaxStubSize();
+
+      Addr = (uint8_t *)StubAddress;
+    }
+    RelocationEntry TargetRE(SectionID, Offset, RelType, /*Addend=*/0, IsPCRel,
+                             Size);
+    resolveRelocation(TargetRE, (uint64_t)Addr);
+  } else {
+
+    RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, IsPCRel, Size);
+    if (Value.SymbolName)
+      addRelocationForSymbol(RE, Value.SymbolName);
+    else
+      addRelocationForSection(RE, Value.SectionID);
+  }
+  return ++RelI;
 }
 
+bool
+RuntimeDyldMachO::isCompatibleFormat(const ObjectBuffer *InputBuffer) const {
+  uint32_t Magic = readMachOMagic(InputBuffer->getBufferStart(),
+                                  InputBuffer->getBufferSize());
+  return (Magic == 0xFEEDFACE || Magic == 0xFEEDFACF);
+}
 
-bool RuntimeDyldMachO::isCompatibleFormat(const MemoryBuffer *InputBuffer) const {
-  StringRef Magic = InputBuffer->getBuffer().slice(0, 4);
-  if (Magic == "\xFE\xED\xFA\xCE") return true;
-  if (Magic == "\xCE\xFA\xED\xFE") return true;
-  if (Magic == "\xFE\xED\xFA\xCF") return true;
-  if (Magic == "\xCF\xFA\xED\xFE") return true;
-  return false;
+bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile *Obj) const {
+  return Obj->isMachO();
 }
 
 } // end namespace llvm