xref: /freebsd/contrib/llvm-project/llvm/lib/ExecutionEngine/JITLink/MachO_arm64.cpp (revision b64c5a0ace59af62eff52bfe110a521dc73c937b)
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 #include "llvm/ExecutionEngine/JITLink/DWARFRecordSectionSplitter.h"
15 #include "llvm/ExecutionEngine/JITLink/aarch64.h"
16 
17 #include "DefineExternalSectionStartAndEndSymbols.h"
18 #include "MachOLinkGraphBuilder.h"
19 
20 #define DEBUG_TYPE "jitlink"
21 
22 using namespace llvm;
23 using namespace llvm::jitlink;
24 
25 namespace {
26 
27 class MachOLinkGraphBuilder_arm64 : public MachOLinkGraphBuilder {
28 public:
29   MachOLinkGraphBuilder_arm64(const object::MachOObjectFile &Obj,
30                               SubtargetFeatures Features)
31       : MachOLinkGraphBuilder(Obj, Triple("arm64-apple-darwin"),
32                               std::move(Features), aarch64::getEdgeKindName),
33         NumSymbols(Obj.getSymtabLoadCommand().nsyms) {}
34 
35 private:
36   enum MachOARM64RelocationKind : Edge::Kind {
37     MachOBranch26 = Edge::FirstRelocation,
38     MachOPointer32,
39     MachOPointer64,
40     MachOPointer64Anon,
41     MachOPage21,
42     MachOPageOffset12,
43     MachOGOTPage21,
44     MachOGOTPageOffset12,
45     MachOTLVPage21,
46     MachOTLVPageOffset12,
47     MachOPointerToGOT,
48     MachOPairedAddend,
49     MachOLDRLiteral19,
50     MachODelta32,
51     MachODelta64,
52     MachONegDelta32,
53     MachONegDelta64,
54   };
55 
56   static Expected<MachOARM64RelocationKind>
57   getRelocationKind(const MachO::relocation_info &RI) {
58     switch (RI.r_type) {
59     case MachO::ARM64_RELOC_UNSIGNED:
60       if (!RI.r_pcrel) {
61         if (RI.r_length == 3)
62           return RI.r_extern ? MachOPointer64 : MachOPointer64Anon;
63         else if (RI.r_length == 2)
64           return MachOPointer32;
65       }
66       break;
67     case MachO::ARM64_RELOC_SUBTRACTOR:
68       // SUBTRACTOR must be non-pc-rel, extern, with length 2 or 3.
69       // Initially represent SUBTRACTOR relocations with 'Delta<W>'.
70       // They may be turned into NegDelta<W> by parsePairRelocation.
71       if (!RI.r_pcrel && RI.r_extern) {
72         if (RI.r_length == 2)
73           return MachODelta32;
74         else if (RI.r_length == 3)
75           return MachODelta64;
76       }
77       break;
78     case MachO::ARM64_RELOC_BRANCH26:
79       if (RI.r_pcrel && RI.r_extern && RI.r_length == 2)
80         return MachOBranch26;
81       break;
82     case MachO::ARM64_RELOC_PAGE21:
83       if (RI.r_pcrel && RI.r_extern && RI.r_length == 2)
84         return MachOPage21;
85       break;
86     case MachO::ARM64_RELOC_PAGEOFF12:
87       if (!RI.r_pcrel && RI.r_extern && RI.r_length == 2)
88         return MachOPageOffset12;
89       break;
90     case MachO::ARM64_RELOC_GOT_LOAD_PAGE21:
91       if (RI.r_pcrel && RI.r_extern && RI.r_length == 2)
92         return MachOGOTPage21;
93       break;
94     case MachO::ARM64_RELOC_GOT_LOAD_PAGEOFF12:
95       if (!RI.r_pcrel && RI.r_extern && RI.r_length == 2)
96         return MachOGOTPageOffset12;
97       break;
98     case MachO::ARM64_RELOC_POINTER_TO_GOT:
99       if (RI.r_pcrel && RI.r_extern && RI.r_length == 2)
100         return MachOPointerToGOT;
101       break;
102     case MachO::ARM64_RELOC_ADDEND:
103       if (!RI.r_pcrel && !RI.r_extern && RI.r_length == 2)
104         return MachOPairedAddend;
105       break;
106     case MachO::ARM64_RELOC_TLVP_LOAD_PAGE21:
107       if (RI.r_pcrel && RI.r_extern && RI.r_length == 2)
108         return MachOTLVPage21;
109       break;
110     case MachO::ARM64_RELOC_TLVP_LOAD_PAGEOFF12:
111       if (!RI.r_pcrel && RI.r_extern && RI.r_length == 2)
112         return MachOTLVPageOffset12;
113       break;
114     }
115 
116     return make_error<JITLinkError>(
117         "Unsupported arm64 relocation: address=" +
118         formatv("{0:x8}", RI.r_address) +
119         ", symbolnum=" + formatv("{0:x6}", RI.r_symbolnum) +
120         ", kind=" + formatv("{0:x1}", RI.r_type) +
121         ", pc_rel=" + (RI.r_pcrel ? "true" : "false") +
122         ", extern=" + (RI.r_extern ? "true" : "false") +
123         ", length=" + formatv("{0:d}", RI.r_length));
124   }
125 
126   using PairRelocInfo = std::tuple<Edge::Kind, Symbol *, uint64_t>;
127 
128   // Parses paired SUBTRACTOR/UNSIGNED relocations and, on success,
129   // returns the edge kind and addend to be used.
130   Expected<PairRelocInfo>
131   parsePairRelocation(Block &BlockToFix, Edge::Kind SubtractorKind,
132                       const MachO::relocation_info &SubRI,
133                       orc::ExecutorAddr FixupAddress, const char *FixupContent,
134                       object::relocation_iterator &UnsignedRelItr,
135                       object::relocation_iterator &RelEnd) {
136     using namespace support;
137 
138     assert(((SubtractorKind == MachODelta32 && SubRI.r_length == 2) ||
139             (SubtractorKind == MachODelta64 && SubRI.r_length == 3)) &&
140            "Subtractor kind should match length");
141     assert(SubRI.r_extern && "SUBTRACTOR reloc symbol should be extern");
142     assert(!SubRI.r_pcrel && "SUBTRACTOR reloc should not be PCRel");
143 
144     if (UnsignedRelItr == RelEnd)
145       return make_error<JITLinkError>("arm64 SUBTRACTOR without paired "
146                                       "UNSIGNED relocation");
147 
148     auto UnsignedRI = getRelocationInfo(UnsignedRelItr);
149 
150     if (SubRI.r_address != UnsignedRI.r_address)
151       return make_error<JITLinkError>("arm64 SUBTRACTOR and paired UNSIGNED "
152                                       "point to different addresses");
153 
154     if (SubRI.r_length != UnsignedRI.r_length)
155       return make_error<JITLinkError>("length of arm64 SUBTRACTOR and paired "
156                                       "UNSIGNED reloc must match");
157 
158     Symbol *FromSymbol;
159     if (auto FromSymbolOrErr = findSymbolByIndex(SubRI.r_symbolnum))
160       FromSymbol = FromSymbolOrErr->GraphSymbol;
161     else
162       return FromSymbolOrErr.takeError();
163 
164     // Read the current fixup value.
165     uint64_t FixupValue = 0;
166     if (SubRI.r_length == 3)
167       FixupValue = *(const little64_t *)FixupContent;
168     else
169       FixupValue = *(const little32_t *)FixupContent;
170 
171     // Find 'ToSymbol' using symbol number or address, depending on whether the
172     // paired UNSIGNED relocation is extern.
173     Symbol *ToSymbol = nullptr;
174     if (UnsignedRI.r_extern) {
175       // Find target symbol by symbol index.
176       if (auto ToSymbolOrErr = findSymbolByIndex(UnsignedRI.r_symbolnum))
177         ToSymbol = ToSymbolOrErr->GraphSymbol;
178       else
179         return ToSymbolOrErr.takeError();
180     } else {
181       auto ToSymbolSec = findSectionByIndex(UnsignedRI.r_symbolnum - 1);
182       if (!ToSymbolSec)
183         return ToSymbolSec.takeError();
184       ToSymbol = getSymbolByAddress(*ToSymbolSec, ToSymbolSec->Address);
185       assert(ToSymbol && "No symbol for section");
186       FixupValue -= ToSymbol->getAddress().getValue();
187     }
188 
189     Edge::Kind DeltaKind;
190     Symbol *TargetSymbol;
191     uint64_t Addend;
192 
193     bool FixingFromSymbol = true;
194     if (&BlockToFix == &FromSymbol->getAddressable()) {
195       if (LLVM_UNLIKELY(&BlockToFix == &ToSymbol->getAddressable())) {
196         // From and To are symbols in the same block. Decide direction by offset
197         // instead.
198         if (ToSymbol->getAddress() > FixupAddress)
199           FixingFromSymbol = true;
200         else if (FromSymbol->getAddress() > FixupAddress)
201           FixingFromSymbol = false;
202         else
203           FixingFromSymbol = FromSymbol->getAddress() >= ToSymbol->getAddress();
204       } else
205         FixingFromSymbol = true;
206     } else {
207       if (&BlockToFix == &ToSymbol->getAddressable())
208         FixingFromSymbol = false;
209       else {
210         // BlockToFix was neither FromSymbol nor ToSymbol.
211         return make_error<JITLinkError>("SUBTRACTOR relocation must fix up "
212                                         "either 'A' or 'B' (or a symbol in one "
213                                         "of their alt-entry groups)");
214       }
215     }
216 
217     if (FixingFromSymbol) {
218       TargetSymbol = ToSymbol;
219       DeltaKind = (SubRI.r_length == 3) ? aarch64::Delta64 : aarch64::Delta32;
220       Addend = FixupValue + (FixupAddress - FromSymbol->getAddress());
221       // FIXME: handle extern 'from'.
222     } else {
223       TargetSymbol = &*FromSymbol;
224       DeltaKind =
225           (SubRI.r_length == 3) ? aarch64::NegDelta64 : aarch64::NegDelta32;
226       Addend = FixupValue - (FixupAddress - ToSymbol->getAddress());
227     }
228 
229     return PairRelocInfo(DeltaKind, TargetSymbol, Addend);
230   }
231 
232   Error addRelocations() override {
233     using namespace support;
234     auto &Obj = getObject();
235 
236     LLVM_DEBUG(dbgs() << "Processing relocations:\n");
237 
238     for (auto &S : Obj.sections()) {
239 
240       orc::ExecutorAddr SectionAddress(S.getAddress());
241 
242       // Skip relocations virtual sections.
243       if (S.isVirtual()) {
244         if (S.relocation_begin() != S.relocation_end())
245           return make_error<JITLinkError>("Virtual section contains "
246                                           "relocations");
247         continue;
248       }
249 
250       auto NSec =
251           findSectionByIndex(Obj.getSectionIndex(S.getRawDataRefImpl()));
252       if (!NSec)
253         return NSec.takeError();
254 
255       // Skip relocations for MachO sections without corresponding graph
256       // sections.
257       {
258         if (!NSec->GraphSection) {
259           LLVM_DEBUG({
260             dbgs() << "  Skipping relocations for MachO section "
261                    << NSec->SegName << "/" << NSec->SectName
262                    << " which has no associated graph section\n";
263           });
264           continue;
265         }
266       }
267 
268       for (auto RelItr = S.relocation_begin(), RelEnd = S.relocation_end();
269            RelItr != RelEnd; ++RelItr) {
270 
271         MachO::relocation_info RI = getRelocationInfo(RelItr);
272 
273         // Validate the relocation kind.
274         auto MachORelocKind = getRelocationKind(RI);
275         if (!MachORelocKind)
276           return MachORelocKind.takeError();
277 
278         // Find the address of the value to fix up.
279         orc::ExecutorAddr FixupAddress =
280             SectionAddress + (uint32_t)RI.r_address;
281         LLVM_DEBUG({
282           dbgs() << "  " << NSec->SectName << " + "
283                  << formatv("{0:x8}", RI.r_address) << ":\n";
284         });
285 
286         // Find the block that the fixup points to.
287         Block *BlockToFix = nullptr;
288         {
289           auto SymbolToFixOrErr = findSymbolByAddress(*NSec, FixupAddress);
290           if (!SymbolToFixOrErr)
291             return SymbolToFixOrErr.takeError();
292           BlockToFix = &SymbolToFixOrErr->getBlock();
293         }
294 
295         if (FixupAddress + orc::ExecutorAddrDiff(1ULL << RI.r_length) >
296             BlockToFix->getAddress() + BlockToFix->getContent().size())
297           return make_error<JITLinkError>(
298               "Relocation content extends past end of fixup block");
299 
300         Edge::Kind Kind = Edge::Invalid;
301 
302         // Get a pointer to the fixup content.
303         const char *FixupContent = BlockToFix->getContent().data() +
304                                    (FixupAddress - BlockToFix->getAddress());
305 
306         // The target symbol and addend will be populated by the switch below.
307         Symbol *TargetSymbol = nullptr;
308         uint64_t Addend = 0;
309 
310         if (*MachORelocKind == MachOPairedAddend) {
311           // If this is an Addend relocation then process it and move to the
312           // paired reloc.
313 
314           Addend = SignExtend64(RI.r_symbolnum, 24);
315 
316           ++RelItr;
317           if (RelItr == RelEnd)
318             return make_error<JITLinkError>("Unpaired Addend reloc at " +
319                                             formatv("{0:x16}", FixupAddress));
320           RI = getRelocationInfo(RelItr);
321 
322           MachORelocKind = getRelocationKind(RI);
323           if (!MachORelocKind)
324             return MachORelocKind.takeError();
325 
326           if (*MachORelocKind != MachOBranch26 &&
327               *MachORelocKind != MachOPage21 &&
328               *MachORelocKind != MachOPageOffset12)
329             return make_error<JITLinkError>(
330                 "Invalid relocation pair: Addend + " +
331                 StringRef(getMachOARM64RelocationKindName(*MachORelocKind)));
332 
333           LLVM_DEBUG({
334             dbgs() << "    Addend: value = " << formatv("{0:x6}", Addend)
335                    << ", pair is "
336                    << getMachOARM64RelocationKindName(*MachORelocKind) << "\n";
337           });
338 
339           // Find the address of the value to fix up.
340           orc::ExecutorAddr PairedFixupAddress =
341               SectionAddress + (uint32_t)RI.r_address;
342           if (PairedFixupAddress != FixupAddress)
343             return make_error<JITLinkError>("Paired relocation points at "
344                                             "different target");
345         }
346 
347         switch (*MachORelocKind) {
348         case MachOBranch26: {
349           if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
350             TargetSymbol = TargetSymbolOrErr->GraphSymbol;
351           else
352             return TargetSymbolOrErr.takeError();
353           uint32_t Instr = *(const ulittle32_t *)FixupContent;
354           if ((Instr & 0x7fffffff) != 0x14000000)
355             return make_error<JITLinkError>("BRANCH26 target is not a B or BL "
356                                             "instruction with a zero addend");
357           Kind = aarch64::Branch26PCRel;
358           break;
359         }
360         case MachOPointer32:
361           if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
362             TargetSymbol = TargetSymbolOrErr->GraphSymbol;
363           else
364             return TargetSymbolOrErr.takeError();
365           Addend = *(const ulittle32_t *)FixupContent;
366           Kind = aarch64::Pointer32;
367           break;
368         case MachOPointer64:
369           if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
370             TargetSymbol = TargetSymbolOrErr->GraphSymbol;
371           else
372             return TargetSymbolOrErr.takeError();
373           Addend = *(const ulittle64_t *)FixupContent;
374           Kind = aarch64::Pointer64;
375           break;
376         case MachOPointer64Anon: {
377           orc::ExecutorAddr TargetAddress(*(const ulittle64_t *)FixupContent);
378           auto TargetNSec = findSectionByIndex(RI.r_symbolnum - 1);
379           if (!TargetNSec)
380             return TargetNSec.takeError();
381           if (auto TargetSymbolOrErr =
382                   findSymbolByAddress(*TargetNSec, TargetAddress))
383             TargetSymbol = &*TargetSymbolOrErr;
384           else
385             return TargetSymbolOrErr.takeError();
386           Addend = TargetAddress - TargetSymbol->getAddress();
387           Kind = aarch64::Pointer64;
388           break;
389         }
390         case MachOPage21:
391         case MachOGOTPage21:
392         case MachOTLVPage21: {
393           if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
394             TargetSymbol = TargetSymbolOrErr->GraphSymbol;
395           else
396             return TargetSymbolOrErr.takeError();
397           uint32_t Instr = *(const ulittle32_t *)FixupContent;
398           if ((Instr & 0xffffffe0) != 0x90000000)
399             return make_error<JITLinkError>("PAGE21/GOTPAGE21 target is not an "
400                                             "ADRP instruction with a zero "
401                                             "addend");
402 
403           if (*MachORelocKind == MachOPage21) {
404             Kind = aarch64::Page21;
405           } else if (*MachORelocKind == MachOGOTPage21) {
406             Kind = aarch64::RequestGOTAndTransformToPage21;
407           } else if (*MachORelocKind == MachOTLVPage21) {
408             Kind = aarch64::RequestTLVPAndTransformToPage21;
409           }
410           break;
411         }
412         case MachOPageOffset12: {
413           if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
414             TargetSymbol = TargetSymbolOrErr->GraphSymbol;
415           else
416             return TargetSymbolOrErr.takeError();
417           uint32_t Instr = *(const ulittle32_t *)FixupContent;
418           uint32_t EncodedAddend = (Instr & 0x003FFC00) >> 10;
419           if (EncodedAddend != 0)
420             return make_error<JITLinkError>("GOTPAGEOFF12 target has non-zero "
421                                             "encoded addend");
422           Kind = aarch64::PageOffset12;
423           break;
424         }
425         case MachOGOTPageOffset12:
426         case MachOTLVPageOffset12: {
427           if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
428             TargetSymbol = TargetSymbolOrErr->GraphSymbol;
429           else
430             return TargetSymbolOrErr.takeError();
431           uint32_t Instr = *(const ulittle32_t *)FixupContent;
432           if ((Instr & 0xfffffc00) != 0xf9400000)
433             return make_error<JITLinkError>("GOTPAGEOFF12 target is not an LDR "
434                                             "immediate instruction with a zero "
435                                             "addend");
436 
437           if (*MachORelocKind == MachOGOTPageOffset12) {
438             Kind = aarch64::RequestGOTAndTransformToPageOffset12;
439           } else if (*MachORelocKind == MachOTLVPageOffset12) {
440             Kind = aarch64::RequestTLVPAndTransformToPageOffset12;
441           }
442           break;
443         }
444         case MachOPointerToGOT:
445           if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum))
446             TargetSymbol = TargetSymbolOrErr->GraphSymbol;
447           else
448             return TargetSymbolOrErr.takeError();
449 
450           Kind = aarch64::RequestGOTAndTransformToDelta32;
451           break;
452         case MachODelta32:
453         case MachODelta64: {
454           // We use Delta32/Delta64 to represent SUBTRACTOR relocations.
455           // parsePairRelocation handles the paired reloc, and returns the
456           // edge kind to be used (either Delta32/Delta64, or
457           // NegDelta32/NegDelta64, depending on the direction of the
458           // subtraction) along with the addend.
459           auto PairInfo =
460               parsePairRelocation(*BlockToFix, *MachORelocKind, RI,
461                                   FixupAddress, FixupContent, ++RelItr, RelEnd);
462           if (!PairInfo)
463             return PairInfo.takeError();
464           std::tie(Kind, TargetSymbol, Addend) = *PairInfo;
465           assert(TargetSymbol && "No target symbol from parsePairRelocation?");
466           break;
467         }
468         default:
469           llvm_unreachable("Special relocation kind should not appear in "
470                            "mach-o file");
471         }
472 
473         LLVM_DEBUG({
474           dbgs() << "    ";
475           Edge GE(Kind, FixupAddress - BlockToFix->getAddress(), *TargetSymbol,
476                   Addend);
477           printEdge(dbgs(), *BlockToFix, GE, aarch64::getEdgeKindName(Kind));
478           dbgs() << "\n";
479         });
480         BlockToFix->addEdge(Kind, FixupAddress - BlockToFix->getAddress(),
481                             *TargetSymbol, Addend);
482       }
483     }
484     return Error::success();
485   }
486 
487   /// Return the string name of the given MachO arm64 edge kind.
488   const char *getMachOARM64RelocationKindName(Edge::Kind R) {
489     switch (R) {
490     case MachOBranch26:
491       return "MachOBranch26";
492     case MachOPointer64:
493       return "MachOPointer64";
494     case MachOPointer64Anon:
495       return "MachOPointer64Anon";
496     case MachOPage21:
497       return "MachOPage21";
498     case MachOPageOffset12:
499       return "MachOPageOffset12";
500     case MachOGOTPage21:
501       return "MachOGOTPage21";
502     case MachOGOTPageOffset12:
503       return "MachOGOTPageOffset12";
504     case MachOTLVPage21:
505       return "MachOTLVPage21";
506     case MachOTLVPageOffset12:
507       return "MachOTLVPageOffset12";
508     case MachOPointerToGOT:
509       return "MachOPointerToGOT";
510     case MachOPairedAddend:
511       return "MachOPairedAddend";
512     case MachOLDRLiteral19:
513       return "MachOLDRLiteral19";
514     case MachODelta32:
515       return "MachODelta32";
516     case MachODelta64:
517       return "MachODelta64";
518     case MachONegDelta32:
519       return "MachONegDelta32";
520     case MachONegDelta64:
521       return "MachONegDelta64";
522     default:
523       return getGenericEdgeKindName(static_cast<Edge::Kind>(R));
524     }
525   }
526 
527   unsigned NumSymbols = 0;
528 };
529 
530 } // namespace
531 
532 namespace llvm {
533 namespace jitlink {
534 
535 Error buildTables_MachO_arm64(LinkGraph &G) {
536   LLVM_DEBUG(dbgs() << "Visiting edges in graph:\n");
537 
538   aarch64::GOTTableManager GOT;
539   aarch64::PLTTableManager PLT(GOT);
540   visitExistingEdges(G, GOT, PLT);
541   return Error::success();
542 }
543 
544 class MachOJITLinker_arm64 : public JITLinker<MachOJITLinker_arm64> {
545   friend class JITLinker<MachOJITLinker_arm64>;
546 
547 public:
548   MachOJITLinker_arm64(std::unique_ptr<JITLinkContext> Ctx,
549                        std::unique_ptr<LinkGraph> G,
550                        PassConfiguration PassConfig)
551       : JITLinker(std::move(Ctx), std::move(G), std::move(PassConfig)) {}
552 
553 private:
554   Error applyFixup(LinkGraph &G, Block &B, const Edge &E) const {
555     return aarch64::applyFixup(G, B, E);
556   }
557 
558   uint64_t NullValue = 0;
559 };
560 
561 Expected<std::unique_ptr<LinkGraph>>
562 createLinkGraphFromMachOObject_arm64(MemoryBufferRef ObjectBuffer) {
563   auto MachOObj = object::ObjectFile::createMachOObjectFile(ObjectBuffer);
564   if (!MachOObj)
565     return MachOObj.takeError();
566 
567   auto Features = (*MachOObj)->getFeatures();
568   if (!Features)
569     return Features.takeError();
570 
571   return MachOLinkGraphBuilder_arm64(**MachOObj, std::move(*Features))
572       .buildGraph();
573 }
574 
575 void link_MachO_arm64(std::unique_ptr<LinkGraph> G,
576                       std::unique_ptr<JITLinkContext> Ctx) {
577 
578   PassConfiguration Config;
579 
580   if (Ctx->shouldAddDefaultTargetPasses(G->getTargetTriple())) {
581     // Add a mark-live pass.
582     if (auto MarkLive = Ctx->getMarkLivePass(G->getTargetTriple()))
583       Config.PrePrunePasses.push_back(std::move(MarkLive));
584     else
585       Config.PrePrunePasses.push_back(markAllSymbolsLive);
586 
587     // Add compact unwind splitter pass.
588     Config.PrePrunePasses.push_back(
589         CompactUnwindSplitter("__LD,__compact_unwind"));
590 
591     // Add eh-frame passes.
592     // FIXME: Prune eh-frames for which compact-unwind is available once
593     // we support compact-unwind registration with libunwind.
594     Config.PrePrunePasses.push_back(createEHFrameSplitterPass_MachO_arm64());
595     Config.PrePrunePasses.push_back(createEHFrameEdgeFixerPass_MachO_arm64());
596 
597     // Resolve any external section start / end symbols.
598     Config.PostAllocationPasses.push_back(
599         createDefineExternalSectionStartAndEndSymbolsPass(
600             identifyMachOSectionStartAndEndSymbols));
601 
602     // Add an in-place GOT/Stubs pass.
603     Config.PostPrunePasses.push_back(buildTables_MachO_arm64);
604   }
605 
606   if (auto Err = Ctx->modifyPassConfig(*G, Config))
607     return Ctx->notifyFailed(std::move(Err));
608 
609   // Construct a JITLinker and run the link function.
610   MachOJITLinker_arm64::link(std::move(Ctx), std::move(G), std::move(Config));
611 }
612 
613 LinkGraphPassFunction createEHFrameSplitterPass_MachO_arm64() {
614   return DWARFRecordSectionSplitter("__TEXT,__eh_frame");
615 }
616 
617 LinkGraphPassFunction createEHFrameEdgeFixerPass_MachO_arm64() {
618   return EHFrameEdgeFixer("__TEXT,__eh_frame", aarch64::PointerSize,
619                           aarch64::Pointer32, aarch64::Pointer64,
620                           aarch64::Delta32, aarch64::Delta64,
621                           aarch64::NegDelta32);
622 }
623 
624 } // end namespace jitlink
625 } // end namespace llvm
626