llvm/lib/ExecutionEngine/JITLink/MachO_arm64.cpp

   1 //===---- MachO_arm64.cpp - JIT linker implementation for MachO/arm64 -----===//
   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/arm64 jit-link implementation.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "llvm/ExecutionEngine/JITLink/MachO_arm64.h"
  14
  15 #include "MachOLinkGraphBuilder.h"
  16 #include "PerGraphGOTAndPLTStubsBuilder.h"
  17
  18 #define DEBUG_TYPE "jitlink"
  19
  20 using namespace llvm;
  21 using namespace llvm::jitlink;
  22 using namespace llvm::jitlink::MachO_arm64_Edges;
  23
  24 namespace {
  25
  26 class MachOLinkGraphBuilder_arm64 : public MachOLinkGraphBuilder {
  27 public:
  28   MachOLinkGraphBuilder_arm64(const object::MachOObjectFile &Obj)
  29       : MachOLinkGraphBuilder(Obj, Triple("arm64-apple-darwin"),
  30                               getMachOARM64RelocationKindName),
  31         NumSymbols(Obj.getSymtabLoadCommand().nsyms) {}
  32
  33 private:
  34   static Expected<MachOARM64RelocationKind>
  35   getRelocationKind(const MachO::relocation_info &RI) {
  36     switch (RI.r_type) {
  37     case MachO::ARM64_RELOC_UNSIGNED:
  38       if (!RI.r_pcrel) {
  39         if (RI.r_length == 3)
  40           return RI.r_extern ? Pointer64 : Pointer64Anon;
  41         else if (RI.r_length == 2)
  42           return Pointer32;
  43       }
  44       break;
  45     case MachO::ARM64_RELOC_SUBTRACTOR:
  46       // SUBTRACTOR must be non-pc-rel, extern, with length 2 or 3.
  47       // Initially represent SUBTRACTOR relocations with 'Delta<W>'.
  48       // They may be turned into NegDelta<W> by parsePairRelocation.
  49       if (!RI.r_pcrel && RI.r_extern) {
  50         if (RI.r_length == 2)
  51           return Delta32;
  52         else if (RI.r_length == 3)
  53           return Delta64;
  54       }
  55       break;
  56     case MachO::ARM64_RELOC_BRANCH26:
  57       if (RI.r_pcrel && RI.r_extern && RI.r_length == 2)
  58         return Branch26;
  59       break;
  60     case MachO::ARM64_RELOC_PAGE21:
  61       if (RI.r_pcrel && RI.r_extern && RI.r_length == 2)
  62         return Page21;
  63       break;
  64     case MachO::ARM64_RELOC_PAGEOFF12:
  65       if (!RI.r_pcrel && RI.r_extern && RI.r_length == 2)
  66         return PageOffset12;
  67       break;
  68     case MachO::ARM64_RELOC_GOT_LOAD_PAGE21:
  69       if (RI.r_pcrel && RI.r_extern && RI.r_length == 2)
  70         return GOTPage21;
  71       break;
  72     case MachO::ARM64_RELOC_GOT_LOAD_PAGEOFF12:
  73       if (!RI.r_pcrel && RI.r_extern && RI.r_length == 2)
  74         return GOTPageOffset12;
  75       break;
  76     case MachO::ARM64_RELOC_POINTER_TO_GOT:
  77       if (RI.r_pcrel && RI.r_extern && RI.r_length == 2)
  78         return PointerToGOT;
  79       break;
  80     case MachO::ARM64_RELOC_ADDEND:
  81       if (!RI.r_pcrel && !RI.r_extern && RI.r_length == 2)
  82         return PairedAddend;
  83       break;
  84     }
  85
  86     return make_error<JITLinkError>(
  87         "Unsupported arm64 relocation: address=" +
  88         formatv("{0:x8}", RI.r_address) +
  89         ", symbolnum=" + formatv("{0:x6}", RI.r_symbolnum) +
  90         ", kind=" + formatv("{0:x1}", RI.r_type) +
  91         ", pc_rel=" + (RI.r_pcrel ? "true" : "false") +
  92         ", extern=" + (RI.r_extern ? "true" : "false") +
  93         ", length=" + formatv("{0:d}", RI.r_length));
  94   }
  95
  96   using PairRelocInfo =
  97       std::tuple<MachOARM64RelocationKind, Symbol *, uint64_t>;
  98
  99   // Parses paired SUBTRACTOR/UNSIGNED relocations and, on success,
 100   // returns the edge kind and addend to be used.
 101   Expected<PairRelocInfo>
 102   parsePairRelocation(Block &BlockToFix, Edge::Kind SubtractorKind,
 103                       const MachO::relocation_info &SubRI,
 104                       JITTargetAddress FixupAddress, const char *FixupContent,
 105                       object::relocation_iterator &UnsignedRelItr,
 106                       object::relocation_iterator &RelEnd) {
 107     using namespace support;
 108
 109     assert(((SubtractorKind == Delta32 && SubRI.r_length == 2) ||
 110             (SubtractorKind == Delta64 && SubRI.r_length == 3)) &&
 111            "Subtractor kind should match length");
 112     assert(SubRI.r_extern && "SUBTRACTOR reloc symbol should be extern");
 113     assert(!SubRI.r_pcrel && "SUBTRACTOR reloc should not be PCRel");
 114
 115     if (UnsignedRelItr == RelEnd)
 116       return make_error<JITLinkError>("arm64 SUBTRACTOR without paired "
 117                                       "UNSIGNED relocation");
 118
 119     auto UnsignedRI = getRelocationInfo(UnsignedRelItr);
 120
 121     if (SubRI.r_address != UnsignedRI.r_address)
 122       return make_error<JITLinkError>("arm64 SUBTRACTOR and paired UNSIGNED "
 123                                       "point to different addresses");
 124
 125     if (SubRI.r_length != UnsignedRI.r_length)
 126       return make_error<JITLinkError>("length of arm64 SUBTRACTOR and paired "
 127                                       "UNSIGNED reloc must match");
 128
 129     Symbol *FromSymbol;
 130     if (auto FromSymbolOrErr = findSymbolByIndex(SubRI.r_symbolnum))
 131       FromSymbol = FromSymbolOrErr->GraphSymbol;
 132     else
 133       return FromSymbolOrErr.takeError();
 134
 135     // Read the current fixup value.
 136     uint64_t FixupValue = 0;
 137     if (SubRI.r_length == 3)
 138       FixupValue = *(const little64_t *)FixupContent;
 139     else
 140       FixupValue = *(const little32_t *)FixupContent;
 141
 142     // Find 'ToSymbol' using symbol number or address, depending on whether the
 143     // paired UNSIGNED relocation is extern.
 144     Symbol *ToSymbol = nullptr;
 145     if (UnsignedRI.r_extern) {
 146       // Find target symbol by symbol index.
 147       if (auto ToSymbolOrErr = findSymbolByIndex(UnsignedRI.r_symbolnum))
 148         ToSymbol = ToSymbolOrErr->GraphSymbol;
 149       else
 150         return ToSymbolOrErr.takeError();
 151     } else {
 152       auto ToSymbolSec = findSectionByIndex(UnsignedRI.r_symbolnum - 1);
 153       if (!ToSymbolSec)
 154         return ToSymbolSec.takeError();
 155       ToSymbol = getSymbolByAddress(ToSymbolSec->Address);
 156       assert(ToSymbol && "No symbol for section");
 157       FixupValue -= ToSymbol->getAddress();
 158     }
 159
 160     MachOARM64RelocationKind DeltaKind;
 161     Symbol *TargetSymbol;
 162     uint64_t Addend;
 163     if (&BlockToFix == &FromSymbol->getAddressable()) {
 164       TargetSymbol = ToSymbol;
 165       DeltaKind = (SubRI.r_length == 3) ? Delta64 : Delta32;
 166       Addend = FixupValue + (FixupAddress - FromSymbol->getAddress());
 167       // FIXME: handle extern 'from'.
 168     } else if (&BlockToFix == &ToSymbol->getAddressable()) {
 169       TargetSymbol = &*FromSymbol;
 170       DeltaKind = (SubRI.r_length == 3) ? NegDelta64 : NegDelta32;
 171       Addend = FixupValue - (FixupAddress - ToSymbol->getAddress());
 172     } else {
 173       // BlockToFix was neither FromSymbol nor ToSymbol.
 174       return make_error<JITLinkError>("SUBTRACTOR relocation must fix up "
 175                                       "either 'A' or 'B' (or a symbol in one "
 176                                       "of their alt-entry groups)");
 177     }
 178
 179     return PairRelocInfo(DeltaKind, TargetSymbol, Addend);
 180   }
 181
 182   Error addRelocations() override {
 183     using namespace support;
 184     auto &Obj = getObject();
 185
 186     LLVM_DEBUG(dbgs() << "Processing relocations:\n");
 187
 188     for (auto &S : Obj.sections()) {
 189
 190       JITTargetAddress SectionAddress = S.getAddress();
 191
 192       // Skip relocations virtual sections.
 193       if (S.isVirtual()) {
 194         if (S.relocation_begin() != S.relocation_end())
 195           return make_error<JITLinkError>("Virtual section contains "
 196                                           "relocations");
 197         continue;
 198       }
 199
 200       // Skip relocations for debug symbols.
 201       {
 202         auto &NSec =
 203             getSectionByIndex(Obj.getSectionIndex(S.getRawDataRefImpl()));
 204         if (!NSec.GraphSection) {
 205           LLVM_DEBUG({
 206             dbgs() << "  Skipping relocations for MachO section "
 207                    << NSec.SegName << "/" << NSec.SectName
 208                    << " which has no associated graph section\n";
 209           });
 210           continue;
 211         }
 212       }
 213
 214       for (auto RelItr = S.relocation_begin(), RelEnd = S.relocation_end();
 215            RelItr != RelEnd; ++RelItr) {
 216
 217         MachO::relocation_info RI = getRelocationInfo(RelItr);
 218
 219         // Sanity check the relocation kind.
 220         auto Kind = getRelocationKind(RI);
 221         if (!Kind)
 222           return Kind.takeError();
 223
 224         // Find the address of the value to fix up.
 225         JITTargetAddress FixupAddress = SectionAddress + (uint32_t)RI.r_address;
 226
 227         LLVM_DEBUG({
 228           auto &NSec =
 229               getSectionByIndex(Obj.getSectionIndex(S.getRawDataRefImpl()));
 230           dbgs() << "  " << NSec.SectName << " + "
 231                  << formatv("{0:x8}", RI.r_address) << ":\n";
 232         });
 233
 234         // Find the block that the fixup points to.
 235         Block *BlockToFix = nullptr;
 236         {
 237           auto SymbolToFixOrErr = findSymbolByAddress(FixupAddress);
 238           if (!SymbolToFixOrErr)
 239             return SymbolToFixOrErr.takeError();
 240           BlockToFix = &SymbolToFixOrErr->getBlock();
 241         }
 242
 243         if (FixupAddress + static_cast<JITTargetAddress>(1ULL << RI.r_length) >
 244             BlockToFix->getAddress() + BlockToFix->getContent().size())
 245           return make_error<JITLinkError>(
 246               "Relocation content extends past end of fixup block");
 247
 248         // Get a pointer to the fixup content.
 249         const char *FixupContent = BlockToFix->getContent().data() +
 250                                    (FixupAddress - BlockToFix->getAddress());
 251
 252         // The target symbol and addend will be populated by the switch below.
 253         Symbol *TargetSymbol = nullptr;
 254         uint64_t Addend = 0;
 255
 256         if (*Kind == PairedAddend) {
 257           // If this is an Addend relocation then process it and move to the
 258           // paired reloc.
 259
 260           Addend = SignExtend64(RI.r_symbolnum, 24);
 261
 262           if (RelItr == RelEnd)
 263             return make_error<JITLinkError>("Unpaired Addend reloc at " +
 264                                             formatv("{0:x16}", FixupAddress));
 265           ++RelItr;
 266           RI = getRelocationInfo(RelItr);
 267
 268           Kind = getRelocationKind(RI);
 269           if (!Kind)
 270             return Kind.takeError();
 271
 272           if (*Kind != Branch26 && *Kind != Page21 && *Kind != PageOffset12)
 273             return make_error<JITLinkError>(
 274                 "Invalid relocation pair: Addend + " +
 275                 StringRef(getMachOARM64RelocationKindName(*Kind)));
 276
 277           LLVM_DEBUG({
 278             dbgs() << "    Addend: value = " << formatv("{0:x6}", Addend)
 279                    << ", pair is " << getMachOARM64RelocationKindName(*Kind)
 280                    << "\n";
 281           });
 282
 283           // Find the address of the value to fix up.
 284           JITTargetAddress PairedFixupAddress =
 285               SectionAddress + (uint32_t)RI.r_address;
 286           if (PairedFixupAddress != FixupAddress)
 287             return make_error<JITLinkError>("Paired relocation points at "
 288                                             "different target");
 289         }
 290
 291         switch (*Kind) {
 292         case Branch26: {
 293           if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
 294             TargetSymbol = TargetSymbolOrErr->GraphSymbol;
 295           else
 296             return TargetSymbolOrErr.takeError();
 297           uint32_t Instr = *(const ulittle32_t *)FixupContent;
 298           if ((Instr & 0x7fffffff) != 0x14000000)
 299             return make_error<JITLinkError>("BRANCH26 target is not a B or BL "
 300                                             "instruction with a zero addend");
 301           break;
 302         }
 303         case Pointer32:
 304           if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
 305             TargetSymbol = TargetSymbolOrErr->GraphSymbol;
 306           else
 307             return TargetSymbolOrErr.takeError();
 308           Addend = *(const ulittle32_t *)FixupContent;
 309           break;
 310         case Pointer64:
 311           if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
 312             TargetSymbol = TargetSymbolOrErr->GraphSymbol;
 313           else
 314             return TargetSymbolOrErr.takeError();
 315           Addend = *(const ulittle64_t *)FixupContent;
 316           break;
 317         case Pointer64Anon: {
 318           JITTargetAddress TargetAddress = *(const ulittle64_t *)FixupContent;
 319           if (auto TargetSymbolOrErr = findSymbolByAddress(TargetAddress))
 320             TargetSymbol = &*TargetSymbolOrErr;
 321           else
 322             return TargetSymbolOrErr.takeError();
 323           Addend = TargetAddress - TargetSymbol->getAddress();
 324           break;
 325         }
 326         case Page21:
 327         case GOTPage21: {
 328           if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
 329             TargetSymbol = TargetSymbolOrErr->GraphSymbol;
 330           else
 331             return TargetSymbolOrErr.takeError();
 332           uint32_t Instr = *(const ulittle32_t *)FixupContent;
 333           if ((Instr & 0xffffffe0) != 0x90000000)
 334             return make_error<JITLinkError>("PAGE21/GOTPAGE21 target is not an "
 335                                             "ADRP instruction with a zero "
 336                                             "addend");
 337           break;
 338         }
 339         case PageOffset12: {
 340           if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
 341             TargetSymbol = TargetSymbolOrErr->GraphSymbol;
 342           else
 343             return TargetSymbolOrErr.takeError();
 344           uint32_t Instr = *(const ulittle32_t *)FixupContent;
 345           uint32_t EncodedAddend = (Instr & 0x003FFC00) >> 10;
 346           if (EncodedAddend != 0)
 347             return make_error<JITLinkError>("GOTPAGEOFF12 target has non-zero "
 348                                             "encoded addend");
 349           break;
 350         }
 351         case GOTPageOffset12: {
 352           if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
 353             TargetSymbol = TargetSymbolOrErr->GraphSymbol;
 354           else
 355             return TargetSymbolOrErr.takeError();
 356           uint32_t Instr = *(const ulittle32_t *)FixupContent;
 357           if ((Instr & 0xfffffc00) != 0xf9400000)
 358             return make_error<JITLinkError>("GOTPAGEOFF12 target is not an LDR "
 359                                             "immediate instruction with a zero "
 360                                             "addend");
 361           break;
 362         }
 363         case PointerToGOT:
 364           if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
 365             TargetSymbol = TargetSymbolOrErr->GraphSymbol;
 366           else
 367             return TargetSymbolOrErr.takeError();
 368           break;
 369         case Delta32:
 370         case Delta64: {
 371           // We use Delta32/Delta64 to represent SUBTRACTOR relocations.
 372           // parsePairRelocation handles the paired reloc, and returns the
 373           // edge kind to be used (either Delta32/Delta64, or
 374           // NegDelta32/NegDelta64, depending on the direction of the
 375           // subtraction) along with the addend.
 376           auto PairInfo =
 377               parsePairRelocation(*BlockToFix, *Kind, RI, FixupAddress,
 378                                   FixupContent, ++RelItr, RelEnd);
 379           if (!PairInfo)
 380             return PairInfo.takeError();
 381           std::tie(*Kind, TargetSymbol, Addend) = *PairInfo;
 382           assert(TargetSymbol && "No target symbol from parsePairRelocation?");
 383           break;
 384         }
 385         default:
 386           llvm_unreachable("Special relocation kind should not appear in "
 387                            "mach-o file");
 388         }
 389
 390         LLVM_DEBUG({
 391           dbgs() << "    ";
 392           Edge GE(*Kind, FixupAddress - BlockToFix->getAddress(), *TargetSymbol,
 393                   Addend);
 394           printEdge(dbgs(), *BlockToFix, GE,
 395                     getMachOARM64RelocationKindName(*Kind));
 396           dbgs() << "\n";
 397         });
 398         BlockToFix->addEdge(*Kind, FixupAddress - BlockToFix->getAddress(),
 399                             *TargetSymbol, Addend);
 400       }
 401     }
 402     return Error::success();
 403   }
 404
 405   unsigned NumSymbols = 0;
 406 };
 407
 408 class PerGraphGOTAndPLTStubsBuilder_MachO_arm64
 409     : public PerGraphGOTAndPLTStubsBuilder<
 410           PerGraphGOTAndPLTStubsBuilder_MachO_arm64> {
 411 public:
 412   using PerGraphGOTAndPLTStubsBuilder<
 413       PerGraphGOTAndPLTStubsBuilder_MachO_arm64>::PerGraphGOTAndPLTStubsBuilder;
 414
 415   bool isGOTEdgeToFix(Edge &E) const {
 416     return E.getKind() == GOTPage21 || E.getKind() == GOTPageOffset12 ||
 417            E.getKind() == PointerToGOT;
 418   }
 419
 420   Symbol &createGOTEntry(Symbol &Target) {
 421     auto &GOTEntryBlock = G.createContentBlock(
 422         getGOTSection(), getGOTEntryBlockContent(), 0, 8, 0);
 423     GOTEntryBlock.addEdge(Pointer64, 0, Target, 0);
 424     return G.addAnonymousSymbol(GOTEntryBlock, 0, 8, false, false);
 425   }
 426
 427   void fixGOTEdge(Edge &E, Symbol &GOTEntry) {
 428     if (E.getKind() == GOTPage21 || E.getKind() == GOTPageOffset12) {
 429       // Update the target, but leave the edge addend as-is.
 430       E.setTarget(GOTEntry);
 431     } else if (E.getKind() == PointerToGOT) {
 432       E.setTarget(GOTEntry);
 433       E.setKind(Delta32);
 434     } else
 435       llvm_unreachable("Not a GOT edge?");
 436   }
 437
 438   bool isExternalBranchEdge(Edge &E) {
 439     return E.getKind() == Branch26 && !E.getTarget().isDefined();
 440   }
 441
 442   Symbol &createPLTStub(Symbol &Target) {
 443     auto &StubContentBlock =
 444         G.createContentBlock(getStubsSection(), getStubBlockContent(), 0, 1, 0);
 445     // Re-use GOT entries for stub targets.
 446     auto &GOTEntrySymbol = getGOTEntry(Target);
 447     StubContentBlock.addEdge(LDRLiteral19, 0, GOTEntrySymbol, 0);
 448     return G.addAnonymousSymbol(StubContentBlock, 0, 8, true, false);
 449   }
 450
 451   void fixPLTEdge(Edge &E, Symbol &Stub) {
 452     assert(E.getKind() == Branch26 && "Not a Branch32 edge?");
 453     assert(E.getAddend() == 0 && "Branch32 edge has non-zero addend?");
 454     E.setTarget(Stub);
 455   }
 456
 457 private:
 458   Section &getGOTSection() {
 459     if (!GOTSection)
 460       GOTSection = &G.createSection("$__GOT", sys::Memory::MF_READ);
 461     return *GOTSection;
 462   }
 463
 464   Section &getStubsSection() {
 465     if (!StubsSection) {
 466       auto StubsProt = static_cast<sys::Memory::ProtectionFlags>(
 467           sys::Memory::MF_READ | sys::Memory::MF_EXEC);
 468       StubsSection = &G.createSection("$__STUBS", StubsProt);
 469     }
 470     return *StubsSection;
 471   }
 472
 473   ArrayRef<char> getGOTEntryBlockContent() {
 474     return {reinterpret_cast<const char *>(NullGOTEntryContent),
 475             sizeof(NullGOTEntryContent)};
 476   }
 477
 478   ArrayRef<char> getStubBlockContent() {
 479     return {reinterpret_cast<const char *>(StubContent), sizeof(StubContent)};
 480   }
 481
 482   static const uint8_t NullGOTEntryContent[8];
 483   static const uint8_t StubContent[8];
 484   Section *GOTSection = nullptr;
 485   Section *StubsSection = nullptr;
 486 };
 487
 488 const uint8_t
 489     PerGraphGOTAndPLTStubsBuilder_MachO_arm64::NullGOTEntryContent[8] = {
 490         0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
 491 const uint8_t PerGraphGOTAndPLTStubsBuilder_MachO_arm64::StubContent[8] = {
 492     0x10, 0x00, 0x00, 0x58, // LDR x16, <literal>
 493     0x00, 0x02, 0x1f, 0xd6  // BR  x16
 494 };
 495
 496 } // namespace
 497
 498 namespace llvm {
 499 namespace jitlink {
 500
 501 class MachOJITLinker_arm64 : public JITLinker<MachOJITLinker_arm64> {
 502   friend class JITLinker<MachOJITLinker_arm64>;
 503
 504 public:
 505   MachOJITLinker_arm64(std::unique_ptr<JITLinkContext> Ctx,
 506                        std::unique_ptr<LinkGraph> G,
 507                        PassConfiguration PassConfig)
 508       : JITLinker(std::move(Ctx), std::move(G), std::move(PassConfig)) {}
 509
 510 private:
 511
 512   static unsigned getPageOffset12Shift(uint32_t Instr) {
 513     constexpr uint32_t LoadStoreImm12Mask = 0x3b000000;
 514     constexpr uint32_t Vec128Mask = 0x04800000;
 515
 516     if ((Instr & LoadStoreImm12Mask) == 0x39000000) {
 517       uint32_t ImplicitShift = Instr >> 30;
 518       if (ImplicitShift == 0)
 519         if ((Instr & Vec128Mask) == Vec128Mask)
 520           ImplicitShift = 4;
 521
 522       return ImplicitShift;
 523     }
 524
 525     return 0;
 526   }
 527
 528   Error applyFixup(LinkGraph &G, Block &B, const Edge &E) const {
 529     using namespace support;
 530
 531     char *BlockWorkingMem = B.getAlreadyMutableContent().data();
 532     char *FixupPtr = BlockWorkingMem + E.getOffset();
 533     JITTargetAddress FixupAddress = B.getAddress() + E.getOffset();
 534
 535     switch (E.getKind()) {
 536     case Branch26: {
 537       assert((FixupAddress & 0x3) == 0 && "Branch-inst is not 32-bit aligned");
 538
 539       int64_t Value = E.getTarget().getAddress() - FixupAddress + E.getAddend();
 540
 541       if (static_cast<uint64_t>(Value) & 0x3)
 542         return make_error<JITLinkError>("Branch26 target is not 32-bit "
 543                                         "aligned");
 544
 545       if (Value < -(1 << 27) || Value > ((1 << 27) - 1))
 546         return makeTargetOutOfRangeError(G, B, E);
 547
 548       uint32_t RawInstr = *(little32_t *)FixupPtr;
 549       assert((RawInstr & 0x7fffffff) == 0x14000000 &&
 550              "RawInstr isn't a B or BR immediate instruction");
 551       uint32_t Imm = (static_cast<uint32_t>(Value) & ((1 << 28) - 1)) >> 2;
 552       uint32_t FixedInstr = RawInstr | Imm;
 553       *(little32_t *)FixupPtr = FixedInstr;
 554       break;
 555     }
 556     case Pointer32: {
 557       uint64_t Value = E.getTarget().getAddress() + E.getAddend();
 558       if (Value > std::numeric_limits<uint32_t>::max())
 559         return makeTargetOutOfRangeError(G, B, E);
 560       *(ulittle32_t *)FixupPtr = Value;
 561       break;
 562     }
 563     case Pointer64:
 564     case Pointer64Anon: {
 565       uint64_t Value = E.getTarget().getAddress() + E.getAddend();
 566       *(ulittle64_t *)FixupPtr = Value;
 567       break;
 568     }
 569     case Page21:
 570     case GOTPage21: {
 571       assert((E.getKind() != GOTPage21 || E.getAddend() == 0) &&
 572              "GOTPAGE21 with non-zero addend");
 573       uint64_t TargetPage =
 574           (E.getTarget().getAddress() + E.getAddend()) &
 575             ~static_cast<uint64_t>(4096 - 1);
 576       uint64_t PCPage = FixupAddress & ~static_cast<uint64_t>(4096 - 1);
 577
 578       int64_t PageDelta = TargetPage - PCPage;
 579       if (PageDelta < -(1 << 30) || PageDelta > ((1 << 30) - 1))
 580         return makeTargetOutOfRangeError(G, B, E);
 581
 582       uint32_t RawInstr = *(ulittle32_t *)FixupPtr;
 583       assert((RawInstr & 0xffffffe0) == 0x90000000 &&
 584              "RawInstr isn't an ADRP instruction");
 585       uint32_t ImmLo = (static_cast<uint64_t>(PageDelta) >> 12) & 0x3;
 586       uint32_t ImmHi = (static_cast<uint64_t>(PageDelta) >> 14) & 0x7ffff;
 587       uint32_t FixedInstr = RawInstr | (ImmLo << 29) | (ImmHi << 5);
 588       *(ulittle32_t *)FixupPtr = FixedInstr;
 589       break;
 590     }
 591     case PageOffset12: {
 592       uint64_t TargetOffset =
 593         (E.getTarget().getAddress() + E.getAddend()) & 0xfff;
 594
 595       uint32_t RawInstr = *(ulittle32_t *)FixupPtr;
 596       unsigned ImmShift = getPageOffset12Shift(RawInstr);
 597
 598       if (TargetOffset & ((1 << ImmShift) - 1))
 599         return make_error<JITLinkError>("PAGEOFF12 target is not aligned");
 600
 601       uint32_t EncodedImm = (TargetOffset >> ImmShift) << 10;
 602       uint32_t FixedInstr = RawInstr | EncodedImm;
 603       *(ulittle32_t *)FixupPtr = FixedInstr;
 604       break;
 605     }
 606     case GOTPageOffset12: {
 607       assert(E.getAddend() == 0 && "GOTPAGEOF12 with non-zero addend");
 608
 609       uint32_t RawInstr = *(ulittle32_t *)FixupPtr;
 610       assert((RawInstr & 0xfffffc00) == 0xf9400000 &&
 611              "RawInstr isn't a 64-bit LDR immediate");
 612
 613       uint32_t TargetOffset = E.getTarget().getAddress() & 0xfff;
 614       assert((TargetOffset & 0x7) == 0 && "GOT entry is not 8-byte aligned");
 615       uint32_t EncodedImm = (TargetOffset >> 3) << 10;
 616       uint32_t FixedInstr = RawInstr | EncodedImm;
 617       *(ulittle32_t *)FixupPtr = FixedInstr;
 618       break;
 619     }
 620     case LDRLiteral19: {
 621       assert((FixupAddress & 0x3) == 0 && "LDR is not 32-bit aligned");
 622       assert(E.getAddend() == 0 && "LDRLiteral19 with non-zero addend");
 623       uint32_t RawInstr = *(ulittle32_t *)FixupPtr;
 624       assert(RawInstr == 0x58000010 && "RawInstr isn't a 64-bit LDR literal");
 625       int64_t Delta = E.getTarget().getAddress() - FixupAddress;
 626       if (Delta & 0x3)
 627         return make_error<JITLinkError>("LDR literal target is not 32-bit "
 628                                         "aligned");
 629       if (Delta < -(1 << 20) || Delta > ((1 << 20) - 1))
 630         return makeTargetOutOfRangeError(G, B, E);
 631
 632       uint32_t EncodedImm = (static_cast<uint32_t>(Delta) >> 2) << 5;
 633       uint32_t FixedInstr = RawInstr | EncodedImm;
 634       *(ulittle32_t *)FixupPtr = FixedInstr;
 635       break;
 636     }
 637     case Delta32:
 638     case Delta64:
 639     case NegDelta32:
 640     case NegDelta64: {
 641       int64_t Value;
 642       if (E.getKind() == Delta32 || E.getKind() == Delta64)
 643         Value = E.getTarget().getAddress() - FixupAddress + E.getAddend();
 644       else
 645         Value = FixupAddress - E.getTarget().getAddress() + E.getAddend();
 646
 647       if (E.getKind() == Delta32 || E.getKind() == NegDelta32) {
 648         if (Value < std::numeric_limits<int32_t>::min() ||
 649             Value > std::numeric_limits<int32_t>::max())
 650           return makeTargetOutOfRangeError(G, B, E);
 651         *(little32_t *)FixupPtr = Value;
 652       } else
 653         *(little64_t *)FixupPtr = Value;
 654       break;
 655     }
 656     default:
 657       llvm_unreachable("Unrecognized edge kind");
 658     }
 659
 660     return Error::success();
 661   }
 662
 663   uint64_t NullValue = 0;
 664 };
 665
 666 Expected<std::unique_ptr<LinkGraph>>
 667 createLinkGraphFromMachOObject_arm64(MemoryBufferRef ObjectBuffer) {
 668   auto MachOObj = object::ObjectFile::createMachOObjectFile(ObjectBuffer);
 669   if (!MachOObj)
 670     return MachOObj.takeError();
 671   return MachOLinkGraphBuilder_arm64(**MachOObj).buildGraph();
 672 }
 673
 674 void link_MachO_arm64(std::unique_ptr<LinkGraph> G,
 675                       std::unique_ptr<JITLinkContext> Ctx) {
 676
 677   PassConfiguration Config;
 678
 679   if (Ctx->shouldAddDefaultTargetPasses(G->getTargetTriple())) {
 680     // Add a mark-live pass.
 681     if (auto MarkLive = Ctx->getMarkLivePass(G->getTargetTriple()))
 682       Config.PrePrunePasses.push_back(std::move(MarkLive));
 683     else
 684       Config.PrePrunePasses.push_back(markAllSymbolsLive);
 685
 686     // Add an in-place GOT/Stubs pass.
 687     Config.PostPrunePasses.push_back(
 688         PerGraphGOTAndPLTStubsBuilder_MachO_arm64::asPass);
 689   }
 690
 691   if (auto Err = Ctx->modifyPassConfig(*G, Config))
 692     return Ctx->notifyFailed(std::move(Err));
 693
 694   // Construct a JITLinker and run the link function.
 695   MachOJITLinker_arm64::link(std::move(Ctx), std::move(G), std::move(Config));
 696 }
 697
 698 const char *getMachOARM64RelocationKindName(Edge::Kind R) {
 699   switch (R) {
 700   case Branch26:
 701     return "Branch26";
 702   case Pointer64:
 703     return "Pointer64";
 704   case Pointer64Anon:
 705     return "Pointer64Anon";
 706   case Page21:
 707     return "Page21";
 708   case PageOffset12:
 709     return "PageOffset12";
 710   case GOTPage21:
 711     return "GOTPage21";
 712   case GOTPageOffset12:
 713     return "GOTPageOffset12";
 714   case PointerToGOT:
 715     return "PointerToGOT";
 716   case PairedAddend:
 717     return "PairedAddend";
 718   case LDRLiteral19:
 719     return "LDRLiteral19";
 720   case Delta32:
 721     return "Delta32";
 722   case Delta64:
 723     return "Delta64";
 724   case NegDelta32:
 725     return "NegDelta32";
 726   case NegDelta64:
 727     return "NegDelta64";
 728   default:
 729     return getGenericEdgeKindName(static_cast<Edge::Kind>(R));
 730   }
 731 }
 732
 733 } // end namespace jitlink
 734 } // end namespace llvm