MachO_arm64.cpp revision 360784 
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 "BasicGOTAndStubsBuilder.h"
16#include "MachOLinkGraphBuilder.h"
17
18#define DEBUG_TYPE "jitlink"
19
20using namespace llvm;
21using namespace llvm::jitlink;
22using namespace llvm::jitlink::MachO_arm64_Edges;
23
24namespace {
25
26class MachOLinkGraphBuilder_arm64 : public MachOLinkGraphBuilder {
27public:
28  MachOLinkGraphBuilder_arm64(const object::MachOObjectFile &Obj)
29      : MachOLinkGraphBuilder(Obj),
30        NumSymbols(Obj.getSymtabLoadCommand().nsyms) {}
31
32private:
33  static Expected<MachOARM64RelocationKind>
34  getRelocationKind(const MachO::relocation_info &RI) {
35    switch (RI.r_type) {
36    case MachO::ARM64_RELOC_UNSIGNED:
37      if (!RI.r_pcrel) {
38        if (RI.r_length == 3)
39          return RI.r_extern ? Pointer64 : Pointer64Anon;
40        else if (RI.r_length == 2)
41          return Pointer32;
42      }
43      break;
44    case MachO::ARM64_RELOC_SUBTRACTOR:
45      // SUBTRACTOR must be non-pc-rel, extern, with length 2 or 3.
46      // Initially represent SUBTRACTOR relocations with 'Delta<W>'.
47      // They may be turned into NegDelta<W> by parsePairRelocation.
48      if (!RI.r_pcrel && RI.r_extern) {
49        if (RI.r_length == 2)
50          return Delta32;
51        else if (RI.r_length == 3)
52          return Delta64;
53      }
54      break;
55    case MachO::ARM64_RELOC_BRANCH26:
56      if (RI.r_pcrel && RI.r_extern && RI.r_length == 2)
57        return Branch26;
58      break;
59    case MachO::ARM64_RELOC_PAGE21:
60      if (RI.r_pcrel && RI.r_extern && RI.r_length == 2)
61        return Page21;
62      break;
63    case MachO::ARM64_RELOC_PAGEOFF12:
64      if (!RI.r_pcrel && RI.r_extern && RI.r_length == 2)
65        return PageOffset12;
66      break;
67    case MachO::ARM64_RELOC_GOT_LOAD_PAGE21:
68      if (RI.r_pcrel && RI.r_extern && RI.r_length == 2)
69        return GOTPage21;
70      break;
71    case MachO::ARM64_RELOC_GOT_LOAD_PAGEOFF12:
72      if (!RI.r_pcrel && RI.r_extern && RI.r_length == 2)
73        return GOTPageOffset12;
74      break;
75    case MachO::ARM64_RELOC_POINTER_TO_GOT:
76      if (RI.r_pcrel && RI.r_extern && RI.r_length == 2)
77        return PointerToGOT;
78      break;
79    case MachO::ARM64_RELOC_ADDEND:
80      if (!RI.r_pcrel && !RI.r_extern && RI.r_length == 2)
81        return PairedAddend;
82      break;
83    }
84
85    return make_error<JITLinkError>(
86        "Unsupported arm64 relocation: address=" +
87        formatv("{0:x8}", RI.r_address) +
88        ", symbolnum=" + formatv("{0:x6}", RI.r_symbolnum) +
89        ", kind=" + formatv("{0:x1}", RI.r_type) +
90        ", pc_rel=" + (RI.r_pcrel ? "true" : "false") +
91        ", extern=" + (RI.r_extern ? "true" : "false") +
92        ", length=" + formatv("{0:d}", RI.r_length));
93  }
94
95  MachO::relocation_info
96  getRelocationInfo(const object::relocation_iterator RelItr) {
97    MachO::any_relocation_info ARI =
98        getObject().getRelocation(RelItr->getRawDataRefImpl());
99    MachO::relocation_info RI;
100    memcpy(&RI, &ARI, sizeof(MachO::relocation_info));
101    return RI;
102  }
103
104  using PairRelocInfo =
105      std::tuple<MachOARM64RelocationKind, Symbol *, uint64_t>;
106
107  // Parses paired SUBTRACTOR/UNSIGNED relocations and, on success,
108  // returns the edge kind and addend to be used.
109  Expected<PairRelocInfo>
110  parsePairRelocation(Block &BlockToFix, Edge::Kind SubtractorKind,
111                      const MachO::relocation_info &SubRI,
112                      JITTargetAddress FixupAddress, const char *FixupContent,
113                      object::relocation_iterator &UnsignedRelItr,
114                      object::relocation_iterator &RelEnd) {
115    using namespace support;
116
117    assert(((SubtractorKind == Delta32 && SubRI.r_length == 2) ||
118            (SubtractorKind == Delta64 && SubRI.r_length == 3)) &&
119           "Subtractor kind should match length");
120    assert(SubRI.r_extern && "SUBTRACTOR reloc symbol should be extern");
121    assert(!SubRI.r_pcrel && "SUBTRACTOR reloc should not be PCRel");
122
123    if (UnsignedRelItr == RelEnd)
124      return make_error<JITLinkError>("arm64 SUBTRACTOR without paired "
125                                      "UNSIGNED relocation");
126
127    auto UnsignedRI = getRelocationInfo(UnsignedRelItr);
128
129    if (SubRI.r_address != UnsignedRI.r_address)
130      return make_error<JITLinkError>("arm64 SUBTRACTOR and paired UNSIGNED "
131                                      "point to different addresses");
132
133    if (SubRI.r_length != UnsignedRI.r_length)
134      return make_error<JITLinkError>("length of arm64 SUBTRACTOR and paired "
135                                      "UNSIGNED reloc must match");
136
137    Symbol *FromSymbol;
138    if (auto FromSymbolOrErr = findSymbolByIndex(SubRI.r_symbolnum))
139      FromSymbol = FromSymbolOrErr->GraphSymbol;
140    else
141      return FromSymbolOrErr.takeError();
142
143    // Read the current fixup value.
144    uint64_t FixupValue = 0;
145    if (SubRI.r_length == 3)
146      FixupValue = *(const little64_t *)FixupContent;
147    else
148      FixupValue = *(const little32_t *)FixupContent;
149
150    // Find 'ToSymbol' using symbol number or address, depending on whether the
151    // paired UNSIGNED relocation is extern.
152    Symbol *ToSymbol = nullptr;
153    if (UnsignedRI.r_extern) {
154      // Find target symbol by symbol index.
155      if (auto ToSymbolOrErr = findSymbolByIndex(UnsignedRI.r_symbolnum))
156        ToSymbol = ToSymbolOrErr->GraphSymbol;
157      else
158        return ToSymbolOrErr.takeError();
159    } else {
160      if (auto ToSymbolOrErr = findSymbolByAddress(FixupValue))
161        ToSymbol = &*ToSymbolOrErr;
162      else
163        return ToSymbolOrErr.takeError();
164      FixupValue -= ToSymbol->getAddress();
165    }
166
167    MachOARM64RelocationKind DeltaKind;
168    Symbol *TargetSymbol;
169    uint64_t Addend;
170    if (&BlockToFix == &FromSymbol->getAddressable()) {
171      TargetSymbol = ToSymbol;
172      DeltaKind = (SubRI.r_length == 3) ? Delta64 : Delta32;
173      Addend = FixupValue + (FixupAddress - FromSymbol->getAddress());
174      // FIXME: handle extern 'from'.
175    } else if (&BlockToFix == &ToSymbol->getAddressable()) {
176      TargetSymbol = &*FromSymbol;
177      DeltaKind = (SubRI.r_length == 3) ? NegDelta64 : NegDelta32;
178      Addend = FixupValue - (FixupAddress - ToSymbol->getAddress());
179    } else {
180      // BlockToFix was neither FromSymbol nor ToSymbol.
181      return make_error<JITLinkError>("SUBTRACTOR relocation must fix up "
182                                      "either 'A' or 'B' (or a symbol in one "
183                                      "of their alt-entry groups)");
184    }
185
186    return PairRelocInfo(DeltaKind, TargetSymbol, Addend);
187  }
188
189  Error addRelocations() override {
190    using namespace support;
191    auto &Obj = getObject();
192
193    for (auto &S : Obj.sections()) {
194
195      JITTargetAddress SectionAddress = S.getAddress();
196
197      for (auto RelItr = S.relocation_begin(), RelEnd = S.relocation_end();
198           RelItr != RelEnd; ++RelItr) {
199
200        MachO::relocation_info RI = getRelocationInfo(RelItr);
201
202        // Sanity check the relocation kind.
203        auto Kind = getRelocationKind(RI);
204        if (!Kind)
205          return Kind.takeError();
206
207        // Find the address of the value to fix up.
208        JITTargetAddress FixupAddress = SectionAddress + (uint32_t)RI.r_address;
209
210        LLVM_DEBUG({
211          dbgs() << "Processing " << getMachOARM64RelocationKindName(*Kind)
212                 << " relocation at " << format("0x%016" PRIx64, FixupAddress)
213                 << "\n";
214        });
215
216        // Find the block that the fixup points to.
217        Block *BlockToFix = nullptr;
218        {
219          auto SymbolToFixOrErr = findSymbolByAddress(FixupAddress);
220          if (!SymbolToFixOrErr)
221            return SymbolToFixOrErr.takeError();
222          BlockToFix = &SymbolToFixOrErr->getBlock();
223        }
224
225        if (FixupAddress + static_cast<JITTargetAddress>(1ULL << RI.r_length) >
226            BlockToFix->getAddress() + BlockToFix->getContent().size())
227          return make_error<JITLinkError>(
228              "Relocation content extends past end of fixup block");
229
230        // Get a pointer to the fixup content.
231        const char *FixupContent = BlockToFix->getContent().data() +
232                                   (FixupAddress - BlockToFix->getAddress());
233
234        // The target symbol and addend will be populated by the switch below.
235        Symbol *TargetSymbol = nullptr;
236        uint64_t Addend = 0;
237
238        if (*Kind == PairedAddend) {
239          // If this is an Addend relocation then process it and move to the
240          // paired reloc.
241
242          Addend = RI.r_symbolnum;
243
244          if (RelItr == RelEnd)
245            return make_error<JITLinkError>("Unpaired Addend reloc at " +
246                                            formatv("{0:x16}", FixupAddress));
247          ++RelItr;
248          RI = getRelocationInfo(RelItr);
249
250          Kind = getRelocationKind(RI);
251          if (!Kind)
252            return Kind.takeError();
253
254          if (*Kind != Branch26 && *Kind != Page21 && *Kind != PageOffset12)
255            return make_error<JITLinkError>(
256                "Invalid relocation pair: Addend + " +
257                getMachOARM64RelocationKindName(*Kind));
258          else
259            LLVM_DEBUG({
260              dbgs() << "  pair is " << getMachOARM64RelocationKindName(*Kind)
261                     << "`\n";
262            });
263
264          // Find the address of the value to fix up.
265          JITTargetAddress PairedFixupAddress =
266              SectionAddress + (uint32_t)RI.r_address;
267          if (PairedFixupAddress != FixupAddress)
268            return make_error<JITLinkError>("Paired relocation points at "
269                                            "different target");
270        }
271
272        switch (*Kind) {
273        case Branch26: {
274          if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
275            TargetSymbol = TargetSymbolOrErr->GraphSymbol;
276          else
277            return TargetSymbolOrErr.takeError();
278          uint32_t Instr = *(const ulittle32_t *)FixupContent;
279          if ((Instr & 0x7fffffff) != 0x14000000)
280            return make_error<JITLinkError>("BRANCH26 target is not a B or BL "
281                                            "instruction with a zero addend");
282          break;
283        }
284        case Pointer32:
285          if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
286            TargetSymbol = TargetSymbolOrErr->GraphSymbol;
287          else
288            return TargetSymbolOrErr.takeError();
289          Addend = *(const ulittle32_t *)FixupContent;
290          break;
291        case Pointer64:
292          if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
293            TargetSymbol = TargetSymbolOrErr->GraphSymbol;
294          else
295            return TargetSymbolOrErr.takeError();
296          Addend = *(const ulittle64_t *)FixupContent;
297          break;
298        case Pointer64Anon: {
299          JITTargetAddress TargetAddress = *(const ulittle64_t *)FixupContent;
300          if (auto TargetSymbolOrErr = findSymbolByAddress(TargetAddress))
301            TargetSymbol = &*TargetSymbolOrErr;
302          else
303            return TargetSymbolOrErr.takeError();
304          Addend = TargetAddress - TargetSymbol->getAddress();
305          break;
306        }
307        case Page21:
308        case GOTPage21: {
309          if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
310            TargetSymbol = TargetSymbolOrErr->GraphSymbol;
311          else
312            return TargetSymbolOrErr.takeError();
313          uint32_t Instr = *(const ulittle32_t *)FixupContent;
314          if ((Instr & 0xffffffe0) != 0x90000000)
315            return make_error<JITLinkError>("PAGE21/GOTPAGE21 target is not an "
316                                            "ADRP instruction with a zero "
317                                            "addend");
318          break;
319        }
320        case PageOffset12: {
321          if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
322            TargetSymbol = TargetSymbolOrErr->GraphSymbol;
323          else
324            return TargetSymbolOrErr.takeError();
325          break;
326        }
327        case GOTPageOffset12: {
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 & 0xfffffc00) != 0xf9400000)
334            return make_error<JITLinkError>("GOTPAGEOFF12 target is not an LDR "
335                                            "immediate instruction with a zero "
336                                            "addend");
337          break;
338        }
339        case PointerToGOT:
340          if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
341            TargetSymbol = TargetSymbolOrErr->GraphSymbol;
342          else
343            return TargetSymbolOrErr.takeError();
344          break;
345        case Delta32:
346        case Delta64: {
347          // We use Delta32/Delta64 to represent SUBTRACTOR relocations.
348          // parsePairRelocation handles the paired reloc, and returns the
349          // edge kind to be used (either Delta32/Delta64, or
350          // NegDelta32/NegDelta64, depending on the direction of the
351          // subtraction) along with the addend.
352          auto PairInfo =
353              parsePairRelocation(*BlockToFix, *Kind, RI, FixupAddress,
354                                  FixupContent, ++RelItr, RelEnd);
355          if (!PairInfo)
356            return PairInfo.takeError();
357          std::tie(*Kind, TargetSymbol, Addend) = *PairInfo;
358          assert(TargetSymbol && "No target symbol from parsePairRelocation?");
359          break;
360        }
361        default:
362          llvm_unreachable("Special relocation kind should not appear in "
363                           "mach-o file");
364        }
365
366        LLVM_DEBUG({
367          Edge GE(*Kind, FixupAddress - BlockToFix->getAddress(), *TargetSymbol,
368                  Addend);
369          printEdge(dbgs(), *BlockToFix, GE,
370                    getMachOARM64RelocationKindName(*Kind));
371          dbgs() << "\n";
372        });
373        BlockToFix->addEdge(*Kind, FixupAddress - BlockToFix->getAddress(),
374                            *TargetSymbol, Addend);
375      }
376    }
377    return Error::success();
378  }
379
380  unsigned NumSymbols = 0;
381};
382
383class MachO_arm64_GOTAndStubsBuilder
384    : public BasicGOTAndStubsBuilder<MachO_arm64_GOTAndStubsBuilder> {
385public:
386  MachO_arm64_GOTAndStubsBuilder(LinkGraph &G)
387      : BasicGOTAndStubsBuilder<MachO_arm64_GOTAndStubsBuilder>(G) {}
388
389  bool isGOTEdge(Edge &E) const {
390    return E.getKind() == GOTPage21 || E.getKind() == GOTPageOffset12 ||
391           E.getKind() == PointerToGOT;
392  }
393
394  Symbol &createGOTEntry(Symbol &Target) {
395    auto &GOTEntryBlock = G.createContentBlock(
396        getGOTSection(), getGOTEntryBlockContent(), 0, 8, 0);
397    GOTEntryBlock.addEdge(Pointer64, 0, Target, 0);
398    return G.addAnonymousSymbol(GOTEntryBlock, 0, 8, false, false);
399  }
400
401  void fixGOTEdge(Edge &E, Symbol &GOTEntry) {
402    if (E.getKind() == GOTPage21 || E.getKind() == GOTPageOffset12) {
403      // Update the target, but leave the edge addend as-is.
404      E.setTarget(GOTEntry);
405    } else if (E.getKind() == PointerToGOT) {
406      E.setTarget(GOTEntry);
407      E.setKind(Delta32);
408    } else
409      llvm_unreachable("Not a GOT edge?");
410  }
411
412  bool isExternalBranchEdge(Edge &E) {
413    return E.getKind() == Branch26 && !E.getTarget().isDefined();
414  }
415
416  Symbol &createStub(Symbol &Target) {
417    auto &StubContentBlock =
418        G.createContentBlock(getStubsSection(), getStubBlockContent(), 0, 1, 0);
419    // Re-use GOT entries for stub targets.
420    auto &GOTEntrySymbol = getGOTEntrySymbol(Target);
421    StubContentBlock.addEdge(LDRLiteral19, 0, GOTEntrySymbol, 0);
422    return G.addAnonymousSymbol(StubContentBlock, 0, 8, true, false);
423  }
424
425  void fixExternalBranchEdge(Edge &E, Symbol &Stub) {
426    assert(E.getKind() == Branch26 && "Not a Branch32 edge?");
427    assert(E.getAddend() == 0 && "Branch32 edge has non-zero addend?");
428    E.setTarget(Stub);
429  }
430
431private:
432  Section &getGOTSection() {
433    if (!GOTSection)
434      GOTSection = &G.createSection("$__GOT", sys::Memory::MF_READ);
435    return *GOTSection;
436  }
437
438  Section &getStubsSection() {
439    if (!StubsSection) {
440      auto StubsProt = static_cast<sys::Memory::ProtectionFlags>(
441          sys::Memory::MF_READ | sys::Memory::MF_EXEC);
442      StubsSection = &G.createSection("$__STUBS", StubsProt);
443    }
444    return *StubsSection;
445  }
446
447  StringRef getGOTEntryBlockContent() {
448    return StringRef(reinterpret_cast<const char *>(NullGOTEntryContent),
449                     sizeof(NullGOTEntryContent));
450  }
451
452  StringRef getStubBlockContent() {
453    return StringRef(reinterpret_cast<const char *>(StubContent),
454                     sizeof(StubContent));
455  }
456
457  static const uint8_t NullGOTEntryContent[8];
458  static const uint8_t StubContent[8];
459  Section *GOTSection = nullptr;
460  Section *StubsSection = nullptr;
461};
462
463const uint8_t MachO_arm64_GOTAndStubsBuilder::NullGOTEntryContent[8] = {
464    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
465const uint8_t MachO_arm64_GOTAndStubsBuilder::StubContent[8] = {
466    0x10, 0x00, 0x00, 0x58, // LDR x16, <literal>
467    0x00, 0x02, 0x1f, 0xd6  // BR  x16
468};
469
470} // namespace
471
472namespace llvm {
473namespace jitlink {
474
475class MachOJITLinker_arm64 : public JITLinker<MachOJITLinker_arm64> {
476  friend class JITLinker<MachOJITLinker_arm64>;
477
478public:
479  MachOJITLinker_arm64(std::unique_ptr<JITLinkContext> Ctx,
480                       PassConfiguration PassConfig)
481      : JITLinker(std::move(Ctx), std::move(PassConfig)) {}
482
483private:
484  StringRef getEdgeKindName(Edge::Kind R) const override {
485    return getMachOARM64RelocationKindName(R);
486  }
487
488  Expected<std::unique_ptr<LinkGraph>>
489  buildGraph(MemoryBufferRef ObjBuffer) override {
490    auto MachOObj = object::ObjectFile::createMachOObjectFile(ObjBuffer);
491    if (!MachOObj)
492      return MachOObj.takeError();
493    return MachOLinkGraphBuilder_arm64(**MachOObj).buildGraph();
494  }
495
496  static Error targetOutOfRangeError(const Block &B, const Edge &E) {
497    std::string ErrMsg;
498    {
499      raw_string_ostream ErrStream(ErrMsg);
500      ErrStream << "Relocation target out of range: ";
501      printEdge(ErrStream, B, E, getMachOARM64RelocationKindName(E.getKind()));
502      ErrStream << "\n";
503    }
504    return make_error<JITLinkError>(std::move(ErrMsg));
505  }
506
507  static unsigned getPageOffset12Shift(uint32_t Instr) {
508    constexpr uint32_t LDRLiteralMask = 0x3ffffc00;
509
510    // Check for a GPR LDR immediate with a zero embedded literal.
511    // If found, the top two bits contain the shift.
512    if ((Instr & LDRLiteralMask) == 0x39400000)
513      return Instr >> 30;
514
515    // Check for a Neon LDR immediate of size 64-bit or less with a zero
516    // embedded literal. If found, the top two bits contain the shift.
517    if ((Instr & LDRLiteralMask) == 0x3d400000)
518      return Instr >> 30;
519
520    // Check for a Neon LDR immediate of size 128-bit with a zero embedded
521    // literal.
522    constexpr uint32_t SizeBitsMask = 0xc0000000;
523    if ((Instr & (LDRLiteralMask | SizeBitsMask)) == 0x3dc00000)
524      return 4;
525
526    return 0;
527  }
528
529  Error applyFixup(Block &B, const Edge &E, char *BlockWorkingMem) const {
530    using namespace support;
531
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 targetOutOfRangeError(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 targetOutOfRangeError(B, E);
560      *(ulittle32_t *)FixupPtr = Value;
561      break;
562    }
563    case Pointer64: {
564      uint64_t Value = E.getTarget().getAddress() + E.getAddend();
565      *(ulittle64_t *)FixupPtr = Value;
566      break;
567    }
568    case Page21:
569    case GOTPage21: {
570      assert(E.getAddend() == 0 && "PAGE21/GOTPAGE21 with non-zero addend");
571      uint64_t TargetPage =
572          E.getTarget().getAddress() & ~static_cast<uint64_t>(4096 - 1);
573      uint64_t PCPage = B.getAddress() & ~static_cast<uint64_t>(4096 - 1);
574
575      int64_t PageDelta = TargetPage - PCPage;
576      if (PageDelta < -(1 << 30) || PageDelta > ((1 << 30) - 1))
577        return targetOutOfRangeError(B, E);
578
579      uint32_t RawInstr = *(ulittle32_t *)FixupPtr;
580      assert((RawInstr & 0xffffffe0) == 0x90000000 &&
581             "RawInstr isn't an ADRP instruction");
582      uint32_t ImmLo = (static_cast<uint64_t>(PageDelta) >> 12) & 0x3;
583      uint32_t ImmHi = (static_cast<uint64_t>(PageDelta) >> 14) & 0x7ffff;
584      uint32_t FixedInstr = RawInstr | (ImmLo << 29) | (ImmHi << 5);
585      *(ulittle32_t *)FixupPtr = FixedInstr;
586      break;
587    }
588    case PageOffset12: {
589      assert(E.getAddend() == 0 && "PAGEOFF12 with non-zero addend");
590      uint64_t TargetOffset = E.getTarget().getAddress() & 0xfff;
591
592      uint32_t RawInstr = *(ulittle32_t *)FixupPtr;
593      unsigned ImmShift = getPageOffset12Shift(RawInstr);
594
595      if (TargetOffset & ((1 << ImmShift) - 1))
596        return make_error<JITLinkError>("PAGEOFF12 target is not aligned");
597
598      uint32_t EncodedImm = (TargetOffset >> ImmShift) << 10;
599      uint32_t FixedInstr = RawInstr | EncodedImm;
600      *(ulittle32_t *)FixupPtr = FixedInstr;
601      break;
602    }
603    case GOTPageOffset12: {
604      assert(E.getAddend() == 0 && "GOTPAGEOF12 with non-zero addend");
605
606      uint32_t RawInstr = *(ulittle32_t *)FixupPtr;
607      assert((RawInstr & 0xfffffc00) == 0xf9400000 &&
608             "RawInstr isn't a 64-bit LDR immediate");
609
610      uint32_t TargetOffset = E.getTarget().getAddress() & 0xfff;
611      assert((TargetOffset & 0x7) == 0 && "GOT entry is not 8-byte aligned");
612      uint32_t EncodedImm = (TargetOffset >> 3) << 10;
613      uint32_t FixedInstr = RawInstr | EncodedImm;
614      *(ulittle32_t *)FixupPtr = FixedInstr;
615      break;
616    }
617    case LDRLiteral19: {
618      assert((FixupAddress & 0x3) == 0 && "LDR is not 32-bit aligned");
619      assert(E.getAddend() == 0 && "LDRLiteral19 with non-zero addend");
620      uint32_t RawInstr = *(ulittle32_t *)FixupPtr;
621      assert(RawInstr == 0x58000010 && "RawInstr isn't a 64-bit LDR literal");
622      int64_t Delta = E.getTarget().getAddress() - FixupAddress;
623      if (Delta & 0x3)
624        return make_error<JITLinkError>("LDR literal target is not 32-bit "
625                                        "aligned");
626      if (Delta < -(1 << 20) || Delta > ((1 << 20) - 1))
627        return targetOutOfRangeError(B, E);
628
629      uint32_t EncodedImm = (static_cast<uint32_t>(Delta) >> 2) << 5;
630      uint32_t FixedInstr = RawInstr | EncodedImm;
631      *(ulittle32_t *)FixupPtr = FixedInstr;
632      break;
633    }
634    case Delta32:
635    case Delta64:
636    case NegDelta32:
637    case NegDelta64: {
638      int64_t Value;
639      if (E.getKind() == Delta32 || E.getKind() == Delta64)
640        Value = E.getTarget().getAddress() - FixupAddress + E.getAddend();
641      else
642        Value = FixupAddress - E.getTarget().getAddress() + E.getAddend();
643
644      if (E.getKind() == Delta32 || E.getKind() == NegDelta32) {
645        if (Value < std::numeric_limits<int32_t>::min() ||
646            Value > std::numeric_limits<int32_t>::max())
647          return targetOutOfRangeError(B, E);
648        *(little32_t *)FixupPtr = Value;
649      } else
650        *(little64_t *)FixupPtr = Value;
651      break;
652    }
653    default:
654      llvm_unreachable("Unrecognized edge kind");
655    }
656
657    return Error::success();
658  }
659
660  uint64_t NullValue = 0;
661};
662
663void jitLink_MachO_arm64(std::unique_ptr<JITLinkContext> Ctx) {
664  PassConfiguration Config;
665  Triple TT("arm64-apple-ios");
666
667  if (Ctx->shouldAddDefaultTargetPasses(TT)) {
668    // Add a mark-live pass.
669    if (auto MarkLive = Ctx->getMarkLivePass(TT))
670      Config.PrePrunePasses.push_back(std::move(MarkLive));
671    else
672      Config.PrePrunePasses.push_back(markAllSymbolsLive);
673
674    // Add an in-place GOT/Stubs pass.
675    Config.PostPrunePasses.push_back([](LinkGraph &G) -> Error {
676      MachO_arm64_GOTAndStubsBuilder(G).run();
677      return Error::success();
678    });
679  }
680
681  if (auto Err = Ctx->modifyPassConfig(TT, Config))
682    return Ctx->notifyFailed(std::move(Err));
683
684  // Construct a JITLinker and run the link function.
685  MachOJITLinker_arm64::link(std::move(Ctx), std::move(Config));
686}
687
688StringRef getMachOARM64RelocationKindName(Edge::Kind R) {
689  switch (R) {
690  case Branch26:
691    return "Branch26";
692  case Pointer64:
693    return "Pointer64";
694  case Pointer64Anon:
695    return "Pointer64Anon";
696  case Page21:
697    return "Page21";
698  case PageOffset12:
699    return "PageOffset12";
700  case GOTPage21:
701    return "GOTPage21";
702  case GOTPageOffset12:
703    return "GOTPageOffset12";
704  case PointerToGOT:
705    return "PointerToGOT";
706  case PairedAddend:
707    return "PairedAddend";
708  case LDRLiteral19:
709    return "LDRLiteral19";
710  case Delta32:
711    return "Delta32";
712  case Delta64:
713    return "Delta64";
714  case NegDelta32:
715    return "NegDelta32";
716  case NegDelta64:
717    return "NegDelta64";
718  default:
719    return getGenericEdgeKindName(static_cast<Edge::Kind>(R));
720  }
721}
722
723} // end namespace jitlink
724} // end namespace llvm
725