[MCJIT] Remove the local symbol table from RuntimeDlyd - it's not needed.
[oota-llvm.git] / lib / ExecutionEngine / RuntimeDyld / RuntimeDyldMachO.cpp
index 66ee50ebe9e35881887755a0ba592cecf814c454..7d4dea630d0741c8cc2f25a110b653b3ac239ab0 100644 (file)
 //
 //===----------------------------------------------------------------------===//
 
-#define DEBUG_TYPE "dyld"
 #include "RuntimeDyldMachO.h"
-#include "llvm/ADT/OwningPtr.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringRef.h"
+
+#include "Targets/RuntimeDyldMachOARM.h"
+#include "Targets/RuntimeDyldMachOAArch64.h"
+#include "Targets/RuntimeDyldMachOI386.h"
+#include "Targets/RuntimeDyldMachOX86_64.h"
+
 using namespace llvm;
 using namespace llvm::object;
 
+#define DEBUG_TYPE "dyld"
+
+namespace {
+
+class LoadedMachOObjectInfo : public RuntimeDyld::LoadedObjectInfo {
+public:
+  LoadedMachOObjectInfo(RuntimeDyldImpl &RTDyld, unsigned BeginIdx,
+                        unsigned EndIdx)
+    : RuntimeDyld::LoadedObjectInfo(RTDyld, BeginIdx, EndIdx) {}
+
+  OwningBinary<ObjectFile>
+  getObjectForDebug(const ObjectFile &Obj) const override {
+    return OwningBinary<ObjectFile>();
+  }
+};
+
+}
+
 namespace llvm {
 
-static unsigned char *processFDE(unsigned char *P, intptr_t DeltaForText, intptr_t DeltaForEH) {
-  uint32_t Length = *((uint32_t*)P);
+int64_t RuntimeDyldMachO::memcpyAddend(const RelocationEntry &RE) const {
+  unsigned NumBytes = 1 << RE.Size;
+  uint8_t *Src = Sections[RE.SectionID].Address + RE.Offset;
+
+  return static_cast<int64_t>(readBytesUnaligned(Src, NumBytes));
+}
+
+RelocationValueRef RuntimeDyldMachO::getRelocationValueRef(
+    const ObjectFile &BaseTObj, const relocation_iterator &RI,
+    const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID) {
+
+  const MachOObjectFile &Obj =
+      static_cast<const MachOObjectFile &>(BaseTObj);
+  MachO::any_relocation_info RelInfo =
+      Obj.getRelocation(RI->getRawDataRefImpl());
+  RelocationValueRef Value;
+
+  bool IsExternal = Obj.getPlainRelocationExternal(RelInfo);
+  if (IsExternal) {
+    symbol_iterator Symbol = RI->getSymbol();
+    StringRef TargetName;
+    Symbol->getName(TargetName);
+    SymbolTableMap::const_iterator SI =
+      GlobalSymbolTable.find(TargetName.data());
+    if (SI != GlobalSymbolTable.end()) {
+      Value.SectionID = SI->second.first;
+      Value.Offset = SI->second.second + RE.Addend;
+    } else {
+      Value.SymbolName = TargetName.data();
+      Value.Offset = RE.Addend;
+    }
+  } else {
+    SectionRef Sec = Obj.getRelocationSection(RelInfo);
+    bool IsCode = Sec.isText();
+    Value.SectionID = findOrEmitSection(Obj, Sec, IsCode, ObjSectionToID);
+    uint64_t Addr = Sec.getAddress();
+    Value.Offset = RE.Addend - Addr;
+  }
+
+  return Value;
+}
+
+void RuntimeDyldMachO::makeValueAddendPCRel(RelocationValueRef &Value,
+                                            const ObjectFile &BaseTObj,
+                                            const relocation_iterator &RI,
+                                            unsigned OffsetToNextPC) {
+  const MachOObjectFile &Obj =
+      static_cast<const MachOObjectFile &>(BaseTObj);
+  MachO::any_relocation_info RelInfo =
+      Obj.getRelocation(RI->getRawDataRefImpl());
+
+  bool IsPCRel = Obj.getAnyRelocationPCRel(RelInfo);
+  if (IsPCRel) {
+    uint64_t RelocAddr = 0;
+    RI->getAddress(RelocAddr);
+    Value.Offset += RelocAddr + OffsetToNextPC;
+  }
+}
+
+void RuntimeDyldMachO::dumpRelocationToResolve(const RelocationEntry &RE,
+                                               uint64_t Value) const {
+  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("0x%016" PRIx64, FinalAddress)
+         << " Value: " << format("0x%016" PRIx64, Value) << " Addend: " << RE.Addend
+         << " isPCRel: " << RE.IsPCRel << " MachoType: " << RE.RelType
+         << " Size: " << (1 << RE.Size) << "\n";
+}
+
+section_iterator
+RuntimeDyldMachO::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 = SI->getAddress();
+    uint64_t SSize = SI->getSize();
+    if ((Addr >= SAddr) && (Addr < SAddr + SSize))
+      return SI;
+  }
+
+  return SE;
+}
+
+
+// Populate __pointers section.
+void RuntimeDyldMachO::populateIndirectSymbolPointersSection(
+                                                    const MachOObjectFile &Obj,
+                                                    const SectionRef &PTSection,
+                                                    unsigned PTSectionID) {
+  assert(!Obj.is64Bit() &&
+         "Pointer table 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 pointer table section "
+               << Sections[PTSectionID].Name
+               << ", 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;
+  }
+}
+
+bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile &Obj) const {
+  return Obj.isMachO();
+}
+
+template <typename Impl>
+void RuntimeDyldMachOCRTPBase<Impl>::finalizeLoad(const ObjectFile &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
+      impl().finalizeSection(ObjImg, i->second, Section);
+  }
+  UnregisteredEHFrameSections.push_back(
+    EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
+}
+
+template <typename Impl>
+unsigned char *RuntimeDyldMachOCRTPBase<Impl>::processFDE(unsigned char *P,
+                                                          int64_t DeltaForText,
+                                                          int64_t DeltaForEH) {
+  typedef typename Impl::TargetPtrT TargetPtrT;
+
+  DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
+               << ", Delta for EH: " << DeltaForEH << "\n");
+  uint32_t Length = readBytesUnaligned(P, 4);
   P += 4;
   unsigned char *Ret = P + Length;
-  uint32_t Offset = *((uint32_t*)P);
+  uint32_t Offset = readBytesUnaligned(P, 4);
   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);
+  TargetPtrT FDELocation = readBytesUnaligned(P, sizeof(TargetPtrT));
+  TargetPtrT NewLocation = FDELocation - DeltaForText;
+  writeBytesUnaligned(NewLocation, P, sizeof(TargetPtrT));
+
+  P += sizeof(TargetPtrT);
 
   // Skip the FDE address range
-  P += sizeof(intptr_t);
+  P += sizeof(TargetPtrT);
 
   uint8_t Augmentationsize = *P;
   P += 1;
   if (Augmentationsize != 0) {
-    intptr_t LSDA = *((intptr_t*)P);
-    intptr_t NewLSDA = LSDA - DeltaForEH;
-    *((intptr_t*)P) = NewLSDA;
+    TargetPtrT LSDA = readBytesUnaligned(P, sizeof(TargetPtrT));
+    TargetPtrT NewLSDA = LSDA - DeltaForEH;
+    writeBytesUnaligned(NewLSDA, P, sizeof(TargetPtrT));
   }
 
   return Ret;
 }
 
-static intptr_t computeDelta(SectionEntry *A, SectionEntry *B) {
-  intptr_t ObjDistance = A->ObjAddress  - B->ObjAddress;
-  intptr_t MemDistance = A->LoadAddress - B->LoadAddress;
+static int64_t computeDelta(SectionEntry *A, SectionEntry *B) {
+  int64_t ObjDistance = A->ObjAddress - B->ObjAddress;
+  int64_t MemDistance = A->LoadAddress - B->LoadAddress;
   return ObjDistance - MemDistance;
 }
 
-void RuntimeDyldMachO::registerEHFrames() {
+template <typename Impl>
+void RuntimeDyldMachOCRTPBase<Impl>::registerEHFrames() {
 
   if (!MemMgr)
     return;
@@ -66,393 +256,46 @@ void RuntimeDyldMachO::registerEHFrames() {
       continue;
     SectionEntry *Text = &Sections[SectionInfo.TextSID];
     SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
-    SectionEntry *ExceptTab = NULL;
+    SectionEntry *ExceptTab = nullptr;
     if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
       ExceptTab = &Sections[SectionInfo.ExceptTabSID];
 
-    intptr_t DeltaForText = computeDelta(Text, EHFrame);
-    intptr_t DeltaForEH = 0;
+    int64_t DeltaForText = computeDelta(Text, EHFrame);
+    int64_t DeltaForEH = 0;
     if (ExceptTab)
       DeltaForEH = computeDelta(ExceptTab, EHFrame);
 
     unsigned char *P = EHFrame->Address;
     unsigned char *End = P + EHFrame->Size;
-    do  {
+    do {
       P = processFDE(P, DeltaForText, DeltaForEH);
-    } while(P != End);
+    } while (P != End);
 
-    MemMgr->registerEHFrames(EHFrame->Address,
-                             EHFrame->LoadAddress,
+    MemMgr->registerEHFrames(EHFrame->Address, EHFrame->LoadAddress,
                              EHFrame->Size);
   }
   UnregisteredEHFrameSections.clear();
 }
 
-void RuntimeDyldMachO::finalizeLoad(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;
-  }
-  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) {
-  const SectionEntry &Section = Sections[RE.SectionID];
-  return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend,
-                           RE.IsPCRel, RE.Size);
-}
-
-void RuntimeDyldMachO::resolveRelocation(const SectionEntry &Section,
-                                         uint64_t Offset,
-                                         uint64_t Value,
-                                         uint32_t Type,
-                                         int64_t Addend,
-                                         bool isPCRel,
-                                         unsigned LogSize) {
-  uint8_t *LocalAddress = Section.Address + Offset;
-  uint64_t FinalAddress = Section.LoadAddress + Offset;
-  unsigned MachoType = Type;
-  unsigned Size = 1 << LogSize;
-
-  DEBUG(dbgs() << "resolveRelocation LocalAddress: "
-        << format("%p", LocalAddress)
-        << " FinalAddress: " << format("%p", FinalAddress)
-        << " Value: " << format("%p", Value)
-        << " Addend: " << Addend
-        << " isPCRel: " << isPCRel
-        << " MachoType: " << MachoType
-        << " Size: " << Size
-        << "\n");
-
-  // This just dispatches to the proper target specific routine.
+std::unique_ptr<RuntimeDyldMachO>
+RuntimeDyldMachO::create(Triple::ArchType Arch, RTDyldMemoryManager *MM) {
   switch (Arch) {
-  default: llvm_unreachable("Unsupported CPU type!");
-  case Triple::x86_64:
-    resolveX86_64Relocation(LocalAddress,
-                            FinalAddress,
-                            (uintptr_t)Value,
-                            isPCRel,
-                            MachoType,
-                            Size,
-                            Addend);
-    break;
-  case Triple::x86:
-    resolveI386Relocation(LocalAddress,
-                          FinalAddress,
-                          (uintptr_t)Value,
-                          isPCRel,
-                          MachoType,
-                          Size,
-                          Addend);
-    break;
-  case Triple::arm:    // Fall through.
-  case Triple::thumb:
-    resolveARMRelocation(LocalAddress,
-                         FinalAddress,
-                         (uintptr_t)Value,
-                         isPCRel,
-                         MachoType,
-                         Size,
-                         Addend);
-    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::GENERIC_RELOC_VANILLA: {
-    uint8_t *p = LocalAddress;
-    uint64_t ValueToWrite = Value + Addend;
-    for (unsigned i = 0; i < Size; ++i) {
-      *p++ = (uint8_t)(ValueToWrite & 0xff);
-      ValueToWrite >>= 8;
-    }
-    return false;
-  }
-  case MachO::GENERIC_RELOC_SECTDIFF:
-  case MachO::GENERIC_RELOC_LOCAL_SECTDIFF:
-  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) {
-  // If the relocation is PC-relative, the value to be encoded is the
-  // pointer difference.
-  if (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;
-
-  switch(Type) {
-  default:
-    llvm_unreachable("Invalid relocation type!");
-  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: {
-    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::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) {
-  // If the relocation is PC-relative, the value to be encoded is the
-  // pointer difference.
-  if (isPCRel) {
-    Value -= FinalAddress;
-    // ARM PCRel relocations have an effective-PC offset of two instructions
-    // (four bytes in Thumb mode, 8 bytes in ARM mode).
-    // FIXME: For now, assume ARM mode.
-    Value -= 8;
-  }
-
-  switch(Type) {
   default:
-    llvm_unreachable("Invalid relocation type!");
-  case MachO::ARM_RELOC_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::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;
-    // The low two bits of the value are not encoded.
-    Value >>= 2;
-    // Mask the value to 24 bits.
-    Value &= 0xffffff;
-    // 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;
+    llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
     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;
-}
-
-void RuntimeDyldMachO::processRelocationRef(unsigned SectionID,
-                                            RelocationRef RelI,
-                                            ObjectImage &Obj,
-                                            ObjSectionToIDMap &ObjSectionToID,
-                                            const SymbolTableMap &Symbols,
-                                            StubMap &Stubs) {
-  const ObjectFile *OF = Obj.getObjectFile();
-  const MachOObjectFile *MachO = static_cast<const MachOObjectFile*>(OF);
-  MachO::any_relocation_info RE= MachO->getRelocation(RelI.getRawDataRefImpl());
-
-  uint32_t RelType = MachO->getAnyRelocationType(RE);
-
-  // FIXME: Properly handle scattered relocations.
-  //        For now, optimistically skip these: they can often be ignored, as
-  //        the static linker will already have applied the relocation, and it
-  //        only needs to be reapplied if symbols move relative to one another.
-  //        Note: This will fail horribly where the relocations *do* need to be
-  //        applied, but that was already the case.
-  if (MachO->isRelocationScattered(RE))
-    return;
-
-  RelocationValueRef Value;
-  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;
-  uint64_t Addend = 0;
-  memcpy(&Addend, LocalAddress, NumBytes);
-
-  if (isExtern) {
-    // Obtain the symbol name which is referenced in the relocation
-    symbol_iterator Symbol = RelI.getSymbol();
-    StringRef TargetName;
-    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 + Addend;
-    } else {
-      // 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 + Addend;
-      } else {
-        Value.SymbolName = TargetName.data();
-        Value.Addend = Addend;
-      }
-    }
-  } else {
-    SectionRef Sec = MachO->getRelocationSection(RE);
-    Value.SectionID = findOrEmitSection(Obj, Sec, true, ObjSectionToID);
-    uint64_t Addr;
-    Sec.getAddress(Addr);
-    Value.Addend = Addend - Addr;
-  }
-
-  if (Arch == Triple::x86_64 && (RelType == MachO::X86_64_RELOC_GOT ||
-                                 RelType == MachO::X86_64_RELOC_GOT_LOAD)) {
-    assert(IsPCRel);
-    assert(Size == 2);
-    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 RE(SectionID, Section.StubOffset,
-                         MachO::X86_64_RELOC_UNSIGNED, 0, false, 3);
-      if (Value.SymbolName)
-        addRelocationForSymbol(RE, Value.SymbolName);
-      else
-        addRelocationForSection(RE, Value.SectionID);
-      Section.StubOffset += 8;
-      Addr = GOTEntry;
-    }
-    resolveRelocation(Section, Offset, (uint64_t)Addr,
-                      MachO::X86_64_RELOC_UNSIGNED, Value.Addend, true, 2);
-  } 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(Section, Offset,
-                        (uint64_t)Section.Address + i->second,
-                        RelType, 0, IsPCRel, Size);
-    else {
-      // Create a new stub function.
-      Stubs[Value] = Section.StubOffset;
-      uint8_t *StubTargetAddr = createStubFunction(Section.Address +
-                                                   Section.StubOffset);
-      RelocationEntry RE(SectionID, StubTargetAddr - Section.Address,
-                         MachO::GENERIC_RELOC_VANILLA, Value.Addend);
-      if (Value.SymbolName)
-        addRelocationForSymbol(RE, Value.SymbolName);
-      else
-        addRelocationForSection(RE, Value.SectionID);
-      resolveRelocation(Section, Offset,
-                        (uint64_t)Section.Address + Section.StubOffset,
-                        RelType, 0, IsPCRel, Size);
-      Section.StubOffset += getMaxStubSize();
-    }
-  } else {
-    RelocationEntry RE(SectionID, Offset, RelType, Value.Addend,
-                       IsPCRel, Size);
-    if (Value.SymbolName)
-      addRelocationForSymbol(RE, Value.SymbolName);
-    else
-      addRelocationForSection(RE, Value.SectionID);
+  case Triple::arm: return make_unique<RuntimeDyldMachOARM>(MM);
+  case Triple::aarch64: return make_unique<RuntimeDyldMachOAArch64>(MM);
+  case Triple::x86: return make_unique<RuntimeDyldMachOI386>(MM);
+  case Triple::x86_64: return make_unique<RuntimeDyldMachOX86_64>(MM);
   }
 }
 
-
-bool RuntimeDyldMachO::isCompatibleFormat(
-        const ObjectBuffer *InputBuffer) const {
-  if (InputBuffer->getBufferSize() < 4)
-    return false;
-  StringRef Magic(InputBuffer->getBufferStart(), 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;
+std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
+RuntimeDyldMachO::loadObject(const object::ObjectFile &O) {
+  unsigned SectionStartIdx, SectionEndIdx;
+  std::tie(SectionStartIdx, SectionEndIdx) = loadObjectImpl(O);
+  return llvm::make_unique<LoadedMachOObjectInfo>(*this, SectionStartIdx,
+                                                  SectionEndIdx);
 }
 
 } // end namespace llvm