lib/ExecutionEngine/JITLink/MachO_x86_64.cpp

   1 //===---- MachO_x86_64.cpp -JIT linker implementation for MachO/x86-64 ----===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // MachO/x86-64 jit-link implementation.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "llvm/ExecutionEngine/JITLink/MachO_x86_64.h"
  14
  15 #include "BasicGOTAndStubsBuilder.h"
  16 #include "MachOAtomGraphBuilder.h"
  17
  18 #define DEBUG_TYPE "jitlink"
  19
  20 using namespace llvm;
  21 using namespace llvm::jitlink;
  22 using namespace llvm::jitlink::MachO_x86_64_Edges;
  23
  24 namespace {
  25
  26 class MachOAtomGraphBuilder_x86_64 : public MachOAtomGraphBuilder {
  27 public:
  28   MachOAtomGraphBuilder_x86_64(const object::MachOObjectFile &Obj)
  29       : MachOAtomGraphBuilder(Obj),
  30         NumSymbols(Obj.getSymtabLoadCommand().nsyms) {
  31     addCustomAtomizer("__eh_frame", [this](MachOSection &EHFrameSection) {
  32       return addEHFrame(getGraph(), EHFrameSection.getGenericSection(),
  33                         EHFrameSection.getContent(),
  34                         EHFrameSection.getAddress(), NegDelta32, Delta64);
  35     });
  36   }
  37
  38 private:
  39   static Expected<MachOX86RelocationKind>
  40   getRelocationKind(const MachO::relocation_info &RI) {
  41     switch (RI.r_type) {
  42     case MachO::X86_64_RELOC_UNSIGNED:
  43       if (!RI.r_pcrel) {
  44         if (RI.r_length == 3)
  45           return RI.r_extern ? Pointer64 : Pointer64Anon;
  46         else if (RI.r_extern && RI.r_length == 2)
  47           return Pointer32;
  48       }
  49       break;
  50     case MachO::X86_64_RELOC_SIGNED:
  51       if (RI.r_pcrel && RI.r_length == 2)
  52         return RI.r_extern ? PCRel32 : PCRel32Anon;
  53       break;
  54     case MachO::X86_64_RELOC_BRANCH:
  55       if (RI.r_pcrel && RI.r_extern && RI.r_length == 2)
  56         return Branch32;
  57       break;
  58     case MachO::X86_64_RELOC_GOT_LOAD:
  59       if (RI.r_pcrel && RI.r_extern && RI.r_length == 2)
  60         return PCRel32GOTLoad;
  61       break;
  62     case MachO::X86_64_RELOC_GOT:
  63       if (RI.r_pcrel && RI.r_extern && RI.r_length == 2)
  64         return PCRel32GOT;
  65       break;
  66     case MachO::X86_64_RELOC_SUBTRACTOR:
  67       // SUBTRACTOR must be non-pc-rel, extern, with length 2 or 3.
  68       // Initially represent SUBTRACTOR relocations with 'Delta<W>'. They may
  69       // be turned into NegDelta<W> by parsePairRelocation.
  70       if (!RI.r_pcrel && RI.r_extern) {
  71         if (RI.r_length == 2)
  72           return Delta32;
  73         else if (RI.r_length == 3)
  74           return Delta64;
  75       }
  76       break;
  77     case MachO::X86_64_RELOC_SIGNED_1:
  78       if (RI.r_pcrel && RI.r_length == 2)
  79         return RI.r_extern ? PCRel32Minus1 : PCRel32Minus1Anon;
  80       break;
  81     case MachO::X86_64_RELOC_SIGNED_2:
  82       if (RI.r_pcrel && RI.r_length == 2)
  83         return RI.r_extern ? PCRel32Minus2 : PCRel32Minus2Anon;
  84       break;
  85     case MachO::X86_64_RELOC_SIGNED_4:
  86       if (RI.r_pcrel && RI.r_length == 2)
  87         return RI.r_extern ? PCRel32Minus4 : PCRel32Minus4Anon;
  88       break;
  89     case MachO::X86_64_RELOC_TLV:
  90       if (RI.r_pcrel && RI.r_extern && RI.r_length == 2)
  91         return PCRel32TLV;
  92       break;
  93     }
  94
  95     return make_error<JITLinkError>(
  96         "Unsupported x86-64 relocation: address=" +
  97         formatv("{0:x8}", RI.r_address) +
  98         ", symbolnum=" + formatv("{0:x6}", RI.r_symbolnum) +
  99         ", kind=" + formatv("{0:x1}", RI.r_type) +
 100         ", pc_rel=" + (RI.r_pcrel ? "true" : "false") +
 101         ", extern=" + (RI.r_extern ? "true" : "false") +
 102         ", length=" + formatv("{0:d}", RI.r_length));
 103   }
 104
 105   Expected<Atom &> findAtomBySymbolIndex(const MachO::relocation_info &RI) {
 106     auto &Obj = getObject();
 107     if (RI.r_symbolnum >= NumSymbols)
 108       return make_error<JITLinkError>("Symbol index out of range");
 109     auto SymI = Obj.getSymbolByIndex(RI.r_symbolnum);
 110     auto Name = SymI->getName();
 111     if (!Name)
 112       return Name.takeError();
 113     return getGraph().getAtomByName(*Name);
 114   }
 115
 116   MachO::relocation_info
 117   getRelocationInfo(const object::relocation_iterator RelItr) {
 118     MachO::any_relocation_info ARI =
 119         getObject().getRelocation(RelItr->getRawDataRefImpl());
 120     MachO::relocation_info RI;
 121     memcpy(&RI, &ARI, sizeof(MachO::relocation_info));
 122     return RI;
 123   }
 124
 125   using PairRelocInfo = std::tuple<MachOX86RelocationKind, Atom *, uint64_t>;
 126
 127   // Parses paired SUBTRACTOR/UNSIGNED relocations and, on success,
 128   // returns the edge kind and addend to be used.
 129   Expected<PairRelocInfo>
 130   parsePairRelocation(DefinedAtom &AtomToFix, Edge::Kind SubtractorKind,
 131                       const MachO::relocation_info &SubRI,
 132                       JITTargetAddress FixupAddress, const char *FixupContent,
 133                       object::relocation_iterator &UnsignedRelItr,
 134                       object::relocation_iterator &RelEnd) {
 135     using namespace support;
 136
 137     assert(((SubtractorKind == Delta32 && SubRI.r_length == 2) ||
 138             (SubtractorKind == Delta64 && SubRI.r_length == 3)) &&
 139            "Subtractor kind should match length");
 140     assert(SubRI.r_extern && "SUBTRACTOR reloc symbol should be extern");
 141     assert(!SubRI.r_pcrel && "SUBTRACTOR reloc should not be PCRel");
 142
 143     if (UnsignedRelItr == RelEnd)
 144       return make_error<JITLinkError>("x86_64 SUBTRACTOR without paired "
 145                                       "UNSIGNED relocation");
 146
 147     auto UnsignedRI = getRelocationInfo(UnsignedRelItr);
 148
 149     if (SubRI.r_address != UnsignedRI.r_address)
 150       return make_error<JITLinkError>("x86_64 SUBTRACTOR and paired UNSIGNED "
 151                                       "point to different addresses");
 152
 153     if (SubRI.r_length != UnsignedRI.r_length)
 154       return make_error<JITLinkError>("length of x86_64 SUBTRACTOR and paired "
 155                                       "UNSIGNED reloc must match");
 156
 157     auto FromAtom = findAtomBySymbolIndex(SubRI);
 158     if (!FromAtom)
 159       return FromAtom.takeError();
 160
 161     // Read the current fixup value.
 162     uint64_t FixupValue = 0;
 163     if (SubRI.r_length == 3)
 164       FixupValue = *(const little64_t *)FixupContent;
 165     else
 166       FixupValue = *(const little32_t *)FixupContent;
 167
 168     // Find 'ToAtom' using symbol number or address, depending on whether the
 169     // paired UNSIGNED relocation is extern.
 170     Atom *ToAtom = nullptr;
 171     if (UnsignedRI.r_extern) {
 172       // Find target atom by symbol index.
 173       if (auto ToAtomOrErr = findAtomBySymbolIndex(UnsignedRI))
 174         ToAtom = &*ToAtomOrErr;
 175       else
 176         return ToAtomOrErr.takeError();
 177     } else {
 178       if (auto ToAtomOrErr = getGraph().findAtomByAddress(FixupValue))
 179         ToAtom = &*ToAtomOrErr;
 180       else
 181         return ToAtomOrErr.takeError();
 182       FixupValue -= ToAtom->getAddress();
 183     }
 184
 185     MachOX86RelocationKind DeltaKind;
 186     Atom *TargetAtom;
 187     uint64_t Addend;
 188     if (areLayoutLocked(AtomToFix, *FromAtom)) {
 189       TargetAtom = ToAtom;
 190       DeltaKind = (SubRI.r_length == 3) ? Delta64 : Delta32;
 191       Addend = FixupValue + (FixupAddress - FromAtom->getAddress());
 192       // FIXME: handle extern 'from'.
 193     } else if (areLayoutLocked(AtomToFix, *ToAtom)) {
 194       TargetAtom = &*FromAtom;
 195       DeltaKind = (SubRI.r_length == 3) ? NegDelta64 : NegDelta32;
 196       Addend = FixupValue - (FixupAddress - ToAtom->getAddress());
 197     } else {
 198       // AtomToFix was neither FromAtom nor ToAtom.
 199       return make_error<JITLinkError>("SUBTRACTOR relocation must fix up "
 200                                       "either 'A' or 'B' (or an atom in one "
 201                                       "of their alt-entry groups)");
 202     }
 203
 204     return PairRelocInfo(DeltaKind, TargetAtom, Addend);
 205   }
 206
 207   Error addRelocations() override {
 208     using namespace support;
 209     auto &G = getGraph();
 210     auto &Obj = getObject();
 211
 212     for (auto &S : Obj.sections()) {
 213
 214       JITTargetAddress SectionAddress = S.getAddress();
 215
 216       for (auto RelItr = S.relocation_begin(), RelEnd = S.relocation_end();
 217            RelItr != RelEnd; ++RelItr) {
 218
 219         MachO::relocation_info RI = getRelocationInfo(RelItr);
 220
 221         // Sanity check the relocation kind.
 222         auto Kind = getRelocationKind(RI);
 223         if (!Kind)
 224           return Kind.takeError();
 225
 226         // Find the address of the value to fix up.
 227         JITTargetAddress FixupAddress = SectionAddress + (uint32_t)RI.r_address;
 228
 229         LLVM_DEBUG({
 230           dbgs() << "Processing relocation at "
 231                  << format("0x%016" PRIx64, FixupAddress) << "\n";
 232         });
 233
 234         // Find the atom that the fixup points to.
 235         DefinedAtom *AtomToFix = nullptr;
 236         {
 237           auto AtomToFixOrErr = G.findAtomByAddress(FixupAddress);
 238           if (!AtomToFixOrErr)
 239             return AtomToFixOrErr.takeError();
 240           AtomToFix = &*AtomToFixOrErr;
 241         }
 242
 243         if (FixupAddress + static_cast<JITTargetAddress>(1ULL << RI.r_length) >
 244             AtomToFix->getAddress() + AtomToFix->getContent().size())
 245           return make_error<JITLinkError>(
 246               "Relocation content extends past end of fixup atom");
 247
 248         // Get a pointer to the fixup content.
 249         const char *FixupContent = AtomToFix->getContent().data() +
 250                                    (FixupAddress - AtomToFix->getAddress());
 251
 252         // The target atom and addend will be populated by the switch below.
 253         Atom *TargetAtom = nullptr;
 254         uint64_t Addend = 0;
 255
 256         switch (*Kind) {
 257         case Branch32:
 258         case PCRel32:
 259         case PCRel32GOTLoad:
 260         case PCRel32GOT:
 261           if (auto TargetAtomOrErr = findAtomBySymbolIndex(RI))
 262             TargetAtom = &*TargetAtomOrErr;
 263           else
 264             return TargetAtomOrErr.takeError();
 265           Addend = *(const ulittle32_t *)FixupContent;
 266           break;
 267         case Pointer32:
 268           if (auto TargetAtomOrErr = findAtomBySymbolIndex(RI))
 269             TargetAtom = &*TargetAtomOrErr;
 270           else
 271             return TargetAtomOrErr.takeError();
 272           Addend = *(const ulittle32_t *)FixupContent;
 273           break;
 274         case Pointer64:
 275           if (auto TargetAtomOrErr = findAtomBySymbolIndex(RI))
 276             TargetAtom = &*TargetAtomOrErr;
 277           else
 278             return TargetAtomOrErr.takeError();
 279           Addend = *(const ulittle64_t *)FixupContent;
 280           break;
 281         case Pointer64Anon: {
 282           JITTargetAddress TargetAddress = *(const ulittle64_t *)FixupContent;
 283           if (auto TargetAtomOrErr = G.findAtomByAddress(TargetAddress))
 284             TargetAtom = &*TargetAtomOrErr;
 285           else
 286             return TargetAtomOrErr.takeError();
 287           Addend = TargetAddress - TargetAtom->getAddress();
 288           break;
 289         }
 290         case PCRel32Minus1:
 291         case PCRel32Minus2:
 292         case PCRel32Minus4:
 293           if (auto TargetAtomOrErr = findAtomBySymbolIndex(RI))
 294             TargetAtom = &*TargetAtomOrErr;
 295           else
 296             return TargetAtomOrErr.takeError();
 297           Addend = *(const ulittle32_t *)FixupContent +
 298                    (1 << (*Kind - PCRel32Minus1));
 299           break;
 300         case PCRel32Anon: {
 301           JITTargetAddress TargetAddress =
 302               FixupAddress + 4 + *(const ulittle32_t *)FixupContent;
 303           if (auto TargetAtomOrErr = G.findAtomByAddress(TargetAddress))
 304             TargetAtom = &*TargetAtomOrErr;
 305           else
 306             return TargetAtomOrErr.takeError();
 307           Addend = TargetAddress - TargetAtom->getAddress();
 308           break;
 309         }
 310         case PCRel32Minus1Anon:
 311         case PCRel32Minus2Anon:
 312         case PCRel32Minus4Anon: {
 313           JITTargetAddress Delta =
 314               static_cast<JITTargetAddress>(1ULL << (*Kind - PCRel32Minus1Anon));
 315           JITTargetAddress TargetAddress =
 316               FixupAddress + 4 + Delta + *(const ulittle32_t *)FixupContent;
 317           if (auto TargetAtomOrErr = G.findAtomByAddress(TargetAddress))
 318             TargetAtom = &*TargetAtomOrErr;
 319           else
 320             return TargetAtomOrErr.takeError();
 321           Addend = TargetAddress - TargetAtom->getAddress();
 322           break;
 323         }
 324         case Delta32:
 325         case Delta64: {
 326           // We use Delta32/Delta64 to represent SUBTRACTOR relocations.
 327           // parsePairRelocation handles the paired reloc, and returns the
 328           // edge kind to be used (either Delta32/Delta64, or
 329           // NegDelta32/NegDelta64, depending on the direction of the
 330           // subtraction) along with the addend.
 331           auto PairInfo =
 332               parsePairRelocation(*AtomToFix, *Kind, RI, FixupAddress,
 333                                   FixupContent, ++RelItr, RelEnd);
 334           if (!PairInfo)
 335             return PairInfo.takeError();
 336           std::tie(*Kind, TargetAtom, Addend) = *PairInfo;
 337           assert(TargetAtom && "No target atom from parsePairRelocation?");
 338           break;
 339         }
 340         default:
 341           llvm_unreachable("Special relocation kind should not appear in "
 342                            "mach-o file");
 343         }
 344
 345         LLVM_DEBUG({
 346           Edge GE(*Kind, FixupAddress - AtomToFix->getAddress(), *TargetAtom,
 347                   Addend);
 348           printEdge(dbgs(), *AtomToFix, GE,
 349                     getMachOX86RelocationKindName(*Kind));
 350           dbgs() << "\n";
 351         });
 352         AtomToFix->addEdge(*Kind, FixupAddress - AtomToFix->getAddress(),
 353                            *TargetAtom, Addend);
 354       }
 355     }
 356     return Error::success();
 357   }
 358
 359   unsigned NumSymbols = 0;
 360 };
 361
 362 class MachO_x86_64_GOTAndStubsBuilder
 363     : public BasicGOTAndStubsBuilder<MachO_x86_64_GOTAndStubsBuilder> {
 364 public:
 365   MachO_x86_64_GOTAndStubsBuilder(AtomGraph &G)
 366       : BasicGOTAndStubsBuilder<MachO_x86_64_GOTAndStubsBuilder>(G) {}
 367
 368   bool isGOTEdge(Edge &E) const {
 369     return E.getKind() == PCRel32GOT || E.getKind() == PCRel32GOTLoad;
 370   }
 371
 372   DefinedAtom &createGOTEntry(Atom &Target) {
 373     auto &GOTEntryAtom = G.addAnonymousAtom(getGOTSection(), 0x0, 8);
 374     GOTEntryAtom.setContent(
 375         StringRef(reinterpret_cast<const char *>(NullGOTEntryContent), 8));
 376     GOTEntryAtom.addEdge(Pointer64, 0, Target, 0);
 377     return GOTEntryAtom;
 378   }
 379
 380   void fixGOTEdge(Edge &E, Atom &GOTEntry) {
 381     assert((E.getKind() == PCRel32GOT || E.getKind() == PCRel32GOTLoad) &&
 382            "Not a GOT edge?");
 383     E.setKind(PCRel32);
 384     E.setTarget(GOTEntry);
 385     // Leave the edge addend as-is.
 386   }
 387
 388   bool isExternalBranchEdge(Edge &E) {
 389     return E.getKind() == Branch32 && !E.getTarget().isDefined();
 390   }
 391
 392   DefinedAtom &createStub(Atom &Target) {
 393     auto &StubAtom = G.addAnonymousAtom(getStubsSection(), 0x0, 2);
 394     StubAtom.setContent(
 395         StringRef(reinterpret_cast<const char *>(StubContent), 6));
 396
 397     // Re-use GOT entries for stub targets.
 398     auto &GOTEntryAtom = getGOTEntryAtom(Target);
 399     StubAtom.addEdge(PCRel32, 2, GOTEntryAtom, 0);
 400
 401     return StubAtom;
 402   }
 403
 404   void fixExternalBranchEdge(Edge &E, Atom &Stub) {
 405     assert(E.getKind() == Branch32 && "Not a Branch32 edge?");
 406     assert(E.getAddend() == 0 && "Branch32 edge has non-zero addend?");
 407     E.setTarget(Stub);
 408   }
 409
 410 private:
 411   Section &getGOTSection() {
 412     if (!GOTSection)
 413       GOTSection = &G.createSection("$__GOT", 8, sys::Memory::MF_READ, false);
 414     return *GOTSection;
 415   }
 416
 417   Section &getStubsSection() {
 418     if (!StubsSection) {
 419       auto StubsProt = static_cast<sys::Memory::ProtectionFlags>(
 420           sys::Memory::MF_READ | sys::Memory::MF_EXEC);
 421       StubsSection = &G.createSection("$__STUBS", 8, StubsProt, false);
 422     }
 423     return *StubsSection;
 424   }
 425
 426   static const uint8_t NullGOTEntryContent[8];
 427   static const uint8_t StubContent[6];
 428   Section *GOTSection = nullptr;
 429   Section *StubsSection = nullptr;
 430 };
 431
 432 const uint8_t MachO_x86_64_GOTAndStubsBuilder::NullGOTEntryContent[8] = {
 433     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
 434 const uint8_t MachO_x86_64_GOTAndStubsBuilder::StubContent[6] = {
 435     0xFF, 0x25, 0x00, 0x00, 0x00, 0x00};
 436 } // namespace
 437
 438 namespace llvm {
 439 namespace jitlink {
 440
 441 class MachOJITLinker_x86_64 : public JITLinker<MachOJITLinker_x86_64> {
 442   friend class JITLinker<MachOJITLinker_x86_64>;
 443
 444 public:
 445   MachOJITLinker_x86_64(std::unique_ptr<JITLinkContext> Ctx,
 446                         PassConfiguration PassConfig)
 447       : JITLinker(std::move(Ctx), std::move(PassConfig)) {}
 448
 449 private:
 450   StringRef getEdgeKindName(Edge::Kind R) const override {
 451     return getMachOX86RelocationKindName(R);
 452   }
 453
 454   Expected<std::unique_ptr<AtomGraph>>
 455   buildGraph(MemoryBufferRef ObjBuffer) override {
 456     auto MachOObj = object::ObjectFile::createMachOObjectFile(ObjBuffer);
 457     if (!MachOObj)
 458       return MachOObj.takeError();
 459     return MachOAtomGraphBuilder_x86_64(**MachOObj).buildGraph();
 460   }
 461
 462   static Error targetOutOfRangeError(const Atom &A, const Edge &E) {
 463     std::string ErrMsg;
 464     {
 465       raw_string_ostream ErrStream(ErrMsg);
 466       ErrStream << "Relocation target out of range: ";
 467       printEdge(ErrStream, A, E, getMachOX86RelocationKindName(E.getKind()));
 468       ErrStream << "\n";
 469     }
 470     return make_error<JITLinkError>(std::move(ErrMsg));
 471   }
 472
 473   Error applyFixup(DefinedAtom &A, const Edge &E, char *AtomWorkingMem) const {
 474     using namespace support;
 475
 476     char *FixupPtr = AtomWorkingMem + E.getOffset();
 477     JITTargetAddress FixupAddress = A.getAddress() + E.getOffset();
 478
 479     switch (E.getKind()) {
 480     case Branch32:
 481     case PCRel32:
 482     case PCRel32Anon: {
 483       int64_t Value =
 484           E.getTarget().getAddress() - (FixupAddress + 4) + E.getAddend();
 485       if (Value < std::numeric_limits<int32_t>::min() ||
 486           Value > std::numeric_limits<int32_t>::max())
 487         return targetOutOfRangeError(A, E);
 488       *(little32_t *)FixupPtr = Value;
 489       break;
 490     }
 491     case Pointer64:
 492     case Pointer64Anon: {
 493       uint64_t Value = E.getTarget().getAddress() + E.getAddend();
 494       *(ulittle64_t *)FixupPtr = Value;
 495       break;
 496     }
 497     case PCRel32Minus1:
 498     case PCRel32Minus2:
 499     case PCRel32Minus4: {
 500       int Delta = 4 + (1 << (E.getKind() - PCRel32Minus1));
 501       int64_t Value =
 502           E.getTarget().getAddress() - (FixupAddress + Delta) + E.getAddend();
 503       if (Value < std::numeric_limits<int32_t>::min() ||
 504           Value > std::numeric_limits<int32_t>::max())
 505         return targetOutOfRangeError(A, E);
 506       *(little32_t *)FixupPtr = Value;
 507       break;
 508     }
 509     case PCRel32Minus1Anon:
 510     case PCRel32Minus2Anon:
 511     case PCRel32Minus4Anon: {
 512       int Delta = 4 + (1 << (E.getKind() - PCRel32Minus1Anon));
 513       int64_t Value =
 514           E.getTarget().getAddress() - (FixupAddress + Delta) + E.getAddend();
 515       if (Value < std::numeric_limits<int32_t>::min() ||
 516           Value > std::numeric_limits<int32_t>::max())
 517         return targetOutOfRangeError(A, E);
 518       *(little32_t *)FixupPtr = Value;
 519       break;
 520     }
 521     case Delta32:
 522     case Delta64:
 523     case NegDelta32:
 524     case NegDelta64: {
 525       int64_t Value;
 526       if (E.getKind() == Delta32 || E.getKind() == Delta64)
 527         Value = E.getTarget().getAddress() - FixupAddress + E.getAddend();
 528       else
 529         Value = FixupAddress - E.getTarget().getAddress() + E.getAddend();
 530
 531       if (E.getKind() == Delta32 || E.getKind() == NegDelta32) {
 532         if (Value < std::numeric_limits<int32_t>::min() ||
 533             Value > std::numeric_limits<int32_t>::max())
 534           return targetOutOfRangeError(A, E);
 535         *(little32_t *)FixupPtr = Value;
 536       } else
 537         *(little64_t *)FixupPtr = Value;
 538       break;
 539     }
 540     case Pointer32: {
 541       uint64_t Value = E.getTarget().getAddress() + E.getAddend();
 542       if (Value > std::numeric_limits<uint32_t>::max())
 543         return targetOutOfRangeError(A, E);
 544       *(ulittle32_t *)FixupPtr = Value;
 545       break;
 546     }
 547     default:
 548       llvm_unreachable("Unrecognized edge kind");
 549     }
 550
 551     return Error::success();
 552   }
 553
 554   uint64_t NullValue = 0;
 555 };
 556
 557 void jitLink_MachO_x86_64(std::unique_ptr<JITLinkContext> Ctx) {
 558   PassConfiguration Config;
 559   Triple TT("x86_64-apple-macosx");
 560
 561   if (Ctx->shouldAddDefaultTargetPasses(TT)) {
 562     // Add a mark-live pass.
 563     if (auto MarkLive = Ctx->getMarkLivePass(TT))
 564       Config.PrePrunePasses.push_back(std::move(MarkLive));
 565     else
 566       Config.PrePrunePasses.push_back(markAllAtomsLive);
 567
 568     // Add an in-place GOT/Stubs pass.
 569     Config.PostPrunePasses.push_back([](AtomGraph &G) -> Error {
 570       MachO_x86_64_GOTAndStubsBuilder(G).run();
 571       return Error::success();
 572     });
 573   }
 574
 575   if (auto Err = Ctx->modifyPassConfig(TT, Config))
 576     return Ctx->notifyFailed(std::move(Err));
 577
 578   // Construct a JITLinker and run the link function.
 579   MachOJITLinker_x86_64::link(std::move(Ctx), std::move(Config));
 580 }
 581
 582 StringRef getMachOX86RelocationKindName(Edge::Kind R) {
 583   switch (R) {
 584   case Branch32:
 585     return "Branch32";
 586   case Pointer32:
 587     return "Pointer32";
 588   case Pointer64:
 589     return "Pointer64";
 590   case Pointer64Anon:
 591     return "Pointer64Anon";
 592   case PCRel32:
 593     return "PCRel32";
 594   case PCRel32Minus1:
 595     return "PCRel32Minus1";
 596   case PCRel32Minus2:
 597     return "PCRel32Minus2";
 598   case PCRel32Minus4:
 599     return "PCRel32Minus4";
 600   case PCRel32Anon:
 601     return "PCRel32Anon";
 602   case PCRel32Minus1Anon:
 603     return "PCRel32Minus1Anon";
 604   case PCRel32Minus2Anon:
 605     return "PCRel32Minus2Anon";
 606   case PCRel32Minus4Anon:
 607     return "PCRel32Minus4Anon";
 608   case PCRel32GOTLoad:
 609     return "PCRel32GOTLoad";
 610   case PCRel32GOT:
 611     return "PCRel32GOT";
 612   case PCRel32TLV:
 613     return "PCRel32TLV";
 614   case Delta32:
 615     return "Delta32";
 616   case Delta64:
 617     return "Delta64";
 618   case NegDelta32:
 619     return "NegDelta32";
 620   case NegDelta64:
 621     return "NegDelta64";
 622   default:
 623     return getGenericEdgeKindName(static_cast<Edge::Kind>(R));
 624   }
 625 }
 626
 627 } // end namespace jitlink
 628 } // end namespace llvm