Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
//===-- llvm-rtdyld.cpp - MCJIT Testing Tool ------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This is a testing tool for use with the MC-JIT LLVM components.
//
//===----------------------------------------------------------------------===//

#include "llvm/ADT/StringMap.h"
#include "llvm/DebugInfo/DIContext.h"
#include "llvm/DebugInfo/DWARF/DWARFContext.h"
#include "llvm/ExecutionEngine/RTDyldMemoryManager.h"
#include "llvm/ExecutionEngine/RuntimeDyld.h"
#include "llvm/ExecutionEngine/RuntimeDyldChecker.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDisassembler/MCDisassembler.h"
#include "llvm/MC/MCInstPrinter.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCTargetOptions.h"
#include "llvm/Object/SymbolSize.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/DynamicLibrary.h"
#include "llvm/Support/InitLLVM.h"
#include "llvm/Support/MSVCErrorWorkarounds.h"
#include "llvm/Support/Memory.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Support/Timer.h"
#include "llvm/Support/raw_ostream.h"

#include <future>
#include <list>

using namespace llvm;
using namespace llvm::object;

static cl::list<std::string>
InputFileList(cl::Positional, cl::ZeroOrMore,
              cl::desc("<input files>"));

enum ActionType {
  AC_Execute,
  AC_PrintObjectLineInfo,
  AC_PrintLineInfo,
  AC_PrintDebugLineInfo,
  AC_Verify
};

static cl::opt<ActionType>
Action(cl::desc("Action to perform:"),
       cl::init(AC_Execute),
       cl::values(clEnumValN(AC_Execute, "execute",
                             "Load, link, and execute the inputs."),
                  clEnumValN(AC_PrintLineInfo, "printline",
                             "Load, link, and print line information for each function."),
                  clEnumValN(AC_PrintDebugLineInfo, "printdebugline",
                             "Load, link, and print line information for each function using the debug object"),
                  clEnumValN(AC_PrintObjectLineInfo, "printobjline",
                             "Like -printlineinfo but does not load the object first"),
                  clEnumValN(AC_Verify, "verify",
                             "Load, link and verify the resulting memory image.")));

static cl::opt<std::string>
EntryPoint("entry",
           cl::desc("Function to call as entry point."),
           cl::init("_main"));

static cl::list<std::string>
Dylibs("dylib",
       cl::desc("Add library."),
       cl::ZeroOrMore);

static cl::list<std::string> InputArgv("args", cl::Positional,
                                       cl::desc("<program arguments>..."),
                                       cl::ZeroOrMore, cl::PositionalEatsArgs);

static cl::opt<std::string>
TripleName("triple", cl::desc("Target triple for disassembler"));

static cl::opt<std::string>
MCPU("mcpu",
     cl::desc("Target a specific cpu type (-mcpu=help for details)"),
     cl::value_desc("cpu-name"),
     cl::init(""));

static cl::list<std::string>
CheckFiles("check",
           cl::desc("File containing RuntimeDyld verifier checks."),
           cl::ZeroOrMore);

static cl::opt<uint64_t>
    PreallocMemory("preallocate",
                   cl::desc("Allocate memory upfront rather than on-demand"),
                   cl::init(0));

static cl::opt<uint64_t> TargetAddrStart(
    "target-addr-start",
    cl::desc("For -verify only: start of phony target address "
             "range."),
    cl::init(4096), // Start at "page 1" - no allocating at "null".
    cl::Hidden);

static cl::opt<uint64_t> TargetAddrEnd(
    "target-addr-end",
    cl::desc("For -verify only: end of phony target address range."),
    cl::init(~0ULL), cl::Hidden);

static cl::opt<uint64_t> TargetSectionSep(
    "target-section-sep",
    cl::desc("For -verify only: Separation between sections in "
             "phony target address space."),
    cl::init(0), cl::Hidden);

static cl::list<std::string>
SpecificSectionMappings("map-section",
                        cl::desc("For -verify only: Map a section to a "
                                 "specific address."),
                        cl::ZeroOrMore,
                        cl::Hidden);

static cl::list<std::string>
DummySymbolMappings("dummy-extern",
                    cl::desc("For -verify only: Inject a symbol into the extern "
                             "symbol table."),
                    cl::ZeroOrMore,
                    cl::Hidden);

static cl::opt<bool>
PrintAllocationRequests("print-alloc-requests",
                        cl::desc("Print allocation requests made to the memory "
                                 "manager by RuntimeDyld"),
                        cl::Hidden);

static cl::opt<bool> ShowTimes("show-times",
                               cl::desc("Show times for llvm-rtdyld phases"),
                               cl::init(false));

ExitOnError ExitOnErr;

struct RTDyldTimers {
  TimerGroup RTDyldTG{"llvm-rtdyld timers", "timers for llvm-rtdyld phases"};
  Timer LoadObjectsTimer{"load", "time to load/add object files", RTDyldTG};
  Timer LinkTimer{"link", "time to link object files", RTDyldTG};
  Timer RunTimer{"run", "time to execute jitlink'd code", RTDyldTG};
};

std::unique_ptr<RTDyldTimers> Timers;

/* *** */

using SectionIDMap = StringMap<unsigned>;
using FileToSectionIDMap = StringMap<SectionIDMap>;

void dumpFileToSectionIDMap(const FileToSectionIDMap &FileToSecIDMap) {
  for (const auto &KV : FileToSecIDMap) {
    llvm::dbgs() << "In " << KV.first() << "\n";
    for (auto &KV2 : KV.second)
      llvm::dbgs() << "  \"" << KV2.first() << "\" -> " << KV2.second << "\n";
  }
}

Expected<unsigned> getSectionId(const FileToSectionIDMap &FileToSecIDMap,
                                StringRef FileName, StringRef SectionName) {
  auto I = FileToSecIDMap.find(FileName);
  if (I == FileToSecIDMap.end())
    return make_error<StringError>("No file named " + FileName,
                                   inconvertibleErrorCode());
  auto &SectionIDs = I->second;
  auto J = SectionIDs.find(SectionName);
  if (J == SectionIDs.end())
    return make_error<StringError>("No section named \"" + SectionName +
                                   "\" in file " + FileName,
                                   inconvertibleErrorCode());
  return J->second;
}

// A trivial memory manager that doesn't do anything fancy, just uses the
// support library allocation routines directly.
class TrivialMemoryManager : public RTDyldMemoryManager {
public:
  struct SectionInfo {
    SectionInfo(StringRef Name, sys::MemoryBlock MB, unsigned SectionID)
        : Name(std::string(Name)), MB(std::move(MB)), SectionID(SectionID) {}
    std::string Name;
    sys::MemoryBlock MB;
    unsigned SectionID = ~0U;
  };

  SmallVector<SectionInfo, 16> FunctionMemory;
  SmallVector<SectionInfo, 16> DataMemory;

  uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment,
                               unsigned SectionID,
                               StringRef SectionName) override;
  uint8_t *allocateDataSection(uintptr_t Size, unsigned Alignment,
                               unsigned SectionID, StringRef SectionName,
                               bool IsReadOnly) override;

  /// If non null, records subsequent Name -> SectionID mappings.
  void setSectionIDsMap(SectionIDMap *SecIDMap) {
    this->SecIDMap = SecIDMap;
  }

  void *getPointerToNamedFunction(const std::string &Name,
                                  bool AbortOnFailure = true) override {
    return nullptr;
  }

  bool finalizeMemory(std::string *ErrMsg) override { return false; }

  void addDummySymbol(const std::string &Name, uint64_t Addr) {
    DummyExterns[Name] = Addr;
  }

  JITSymbol findSymbol(const std::string &Name) override {
    auto I = DummyExterns.find(Name);

    if (I != DummyExterns.end())
      return JITSymbol(I->second, JITSymbolFlags::Exported);

    if (auto Sym = RTDyldMemoryManager::findSymbol(Name))
      return Sym;
    else if (auto Err = Sym.takeError())
      ExitOnErr(std::move(Err));
    else
      ExitOnErr(make_error<StringError>("Could not find definition for \"" +
                                            Name + "\"",
                                        inconvertibleErrorCode()));
    llvm_unreachable("Should have returned or exited by now");
  }

  void registerEHFrames(uint8_t *Addr, uint64_t LoadAddr,
                        size_t Size) override {}
  void deregisterEHFrames() override {}

  void preallocateSlab(uint64_t Size) {
    std::error_code EC;
    sys::MemoryBlock MB =
      sys::Memory::allocateMappedMemory(Size, nullptr,
                                        sys::Memory::MF_READ |
                                        sys::Memory::MF_WRITE,
                                        EC);
    if (!MB.base())
      report_fatal_error("Can't allocate enough memory: " + EC.message());

    PreallocSlab = MB;
    UsePreallocation = true;
    SlabSize = Size;
  }

  uint8_t *allocateFromSlab(uintptr_t Size, unsigned Alignment, bool isCode,
                            StringRef SectionName, unsigned SectionID) {
    Size = alignTo(Size, Alignment);
    if (CurrentSlabOffset + Size > SlabSize)
      report_fatal_error("Can't allocate enough memory. Tune --preallocate");

    uintptr_t OldSlabOffset = CurrentSlabOffset;
    sys::MemoryBlock MB((void *)OldSlabOffset, Size);
    if (isCode)
      FunctionMemory.push_back(SectionInfo(SectionName, MB, SectionID));
    else
      DataMemory.push_back(SectionInfo(SectionName, MB, SectionID));
    CurrentSlabOffset += Size;
    return (uint8_t*)OldSlabOffset;
  }

private:
  std::map<std::string, uint64_t> DummyExterns;
  sys::MemoryBlock PreallocSlab;
  bool UsePreallocation = false;
  uintptr_t SlabSize = 0;
  uintptr_t CurrentSlabOffset = 0;
  SectionIDMap *SecIDMap = nullptr;
};

uint8_t *TrivialMemoryManager::allocateCodeSection(uintptr_t Size,
                                                   unsigned Alignment,
                                                   unsigned SectionID,
                                                   StringRef SectionName) {
  if (PrintAllocationRequests)
    outs() << "allocateCodeSection(Size = " << Size << ", Alignment = "
           << Alignment << ", SectionName = " << SectionName << ")\n";

  if (SecIDMap)
    (*SecIDMap)[SectionName] = SectionID;

  if (UsePreallocation)
    return allocateFromSlab(Size, Alignment, true /* isCode */,
                            SectionName, SectionID);

  std::error_code EC;
  sys::MemoryBlock MB =
    sys::Memory::allocateMappedMemory(Size, nullptr,
                                      sys::Memory::MF_READ |
                                      sys::Memory::MF_WRITE,
                                      EC);
  if (!MB.base())
    report_fatal_error("MemoryManager allocation failed: " + EC.message());
  FunctionMemory.push_back(SectionInfo(SectionName, MB, SectionID));
  return (uint8_t*)MB.base();
}

uint8_t *TrivialMemoryManager::allocateDataSection(uintptr_t Size,
                                                   unsigned Alignment,
                                                   unsigned SectionID,
                                                   StringRef SectionName,
                                                   bool IsReadOnly) {
  if (PrintAllocationRequests)
    outs() << "allocateDataSection(Size = " << Size << ", Alignment = "
           << Alignment << ", SectionName = " << SectionName << ")\n";

  if (SecIDMap)
    (*SecIDMap)[SectionName] = SectionID;

  if (UsePreallocation)
    return allocateFromSlab(Size, Alignment, false /* isCode */, SectionName,
                            SectionID);

  std::error_code EC;
  sys::MemoryBlock MB =
    sys::Memory::allocateMappedMemory(Size, nullptr,
                                      sys::Memory::MF_READ |
                                      sys::Memory::MF_WRITE,
                                      EC);
  if (!MB.base())
    report_fatal_error("MemoryManager allocation failed: " + EC.message());
  DataMemory.push_back(SectionInfo(SectionName, MB, SectionID));
  return (uint8_t*)MB.base();
}

static const char *ProgramName;

static void ErrorAndExit(const Twine &Msg) {
  errs() << ProgramName << ": error: " << Msg << "\n";
  exit(1);
}

static void loadDylibs() {
  for (const std::string &Dylib : Dylibs) {
    if (!sys::fs::is_regular_file(Dylib))
      report_fatal_error("Dylib not found: '" + Dylib + "'.");
    std::string ErrMsg;
    if (sys::DynamicLibrary::LoadLibraryPermanently(Dylib.c_str(), &ErrMsg))
      report_fatal_error("Error loading '" + Dylib + "': " + ErrMsg);
  }
}

/* *** */

static int printLineInfoForInput(bool LoadObjects, bool UseDebugObj) {
  assert(LoadObjects || !UseDebugObj);

  // Load any dylibs requested on the command line.
  loadDylibs();

  // If we don't have any input files, read from stdin.
  if (!InputFileList.size())
    InputFileList.push_back("-");
  for (auto &File : InputFileList) {
    // Instantiate a dynamic linker.
    TrivialMemoryManager MemMgr;
    RuntimeDyld Dyld(MemMgr, MemMgr);

    // Load the input memory buffer.

    ErrorOr<std::unique_ptr<MemoryBuffer>> InputBuffer =
        MemoryBuffer::getFileOrSTDIN(File);
    if (std::error_code EC = InputBuffer.getError())
      ErrorAndExit("unable to read input: '" + EC.message() + "'");

    Expected<std::unique_ptr<ObjectFile>> MaybeObj(
      ObjectFile::createObjectFile((*InputBuffer)->getMemBufferRef()));

    if (!MaybeObj) {
      std::string Buf;
      raw_string_ostream OS(Buf);
      logAllUnhandledErrors(MaybeObj.takeError(), OS);
      OS.flush();
      ErrorAndExit("unable to create object file: '" + Buf + "'");
    }

    ObjectFile &Obj = **MaybeObj;

    OwningBinary<ObjectFile> DebugObj;
    std::unique_ptr<RuntimeDyld::LoadedObjectInfo> LoadedObjInfo = nullptr;
    ObjectFile *SymbolObj = &Obj;
    if (LoadObjects) {
      // Load the object file
      LoadedObjInfo =
        Dyld.loadObject(Obj);

      if (Dyld.hasError())
        ErrorAndExit(Dyld.getErrorString());

      // Resolve all the relocations we can.
      Dyld.resolveRelocations();

      if (UseDebugObj) {
        DebugObj = LoadedObjInfo->getObjectForDebug(Obj);
        SymbolObj = DebugObj.getBinary();
        LoadedObjInfo.reset();
      }
    }

    std::unique_ptr<DIContext> Context =
        DWARFContext::create(*SymbolObj, LoadedObjInfo.get());

    std::vector<std::pair<SymbolRef, uint64_t>> SymAddr =
        object::computeSymbolSizes(*SymbolObj);

    // Use symbol info to iterate functions in the object.
    for (const auto &P : SymAddr) {
      object::SymbolRef Sym = P.first;
      Expected<SymbolRef::Type> TypeOrErr = Sym.getType();
      if (!TypeOrErr) {
        // TODO: Actually report errors helpfully.
        consumeError(TypeOrErr.takeError());
        continue;
      }
      SymbolRef::Type Type = *TypeOrErr;
      if (Type == object::SymbolRef::ST_Function) {
        Expected<StringRef> Name = Sym.getName();
        if (!Name) {
          // TODO: Actually report errors helpfully.
          consumeError(Name.takeError());
          continue;
        }
        Expected<uint64_t> AddrOrErr = Sym.getAddress();
        if (!AddrOrErr) {
          // TODO: Actually report errors helpfully.
          consumeError(AddrOrErr.takeError());
          continue;
        }
        uint64_t Addr = *AddrOrErr;

        object::SectionedAddress Address;

        uint64_t Size = P.second;
        // If we're not using the debug object, compute the address of the
        // symbol in memory (rather than that in the unrelocated object file)
        // and use that to query the DWARFContext.
        if (!UseDebugObj && LoadObjects) {
          auto SecOrErr = Sym.getSection();
          if (!SecOrErr) {
            // TODO: Actually report errors helpfully.
            consumeError(SecOrErr.takeError());
            continue;
          }
          object::section_iterator Sec = *SecOrErr;
          Address.SectionIndex = Sec->getIndex();
          uint64_t SectionLoadAddress =
            LoadedObjInfo->getSectionLoadAddress(*Sec);
          if (SectionLoadAddress != 0)
            Addr += SectionLoadAddress - Sec->getAddress();
        } else if (auto SecOrErr = Sym.getSection())
          Address.SectionIndex = SecOrErr.get()->getIndex();

        outs() << "Function: " << *Name << ", Size = " << Size
               << ", Addr = " << Addr << "\n";

        Address.Address = Addr;
        DILineInfoTable Lines =
            Context->getLineInfoForAddressRange(Address, Size);
        for (auto &D : Lines) {
          outs() << "  Line info @ " << D.first - Addr << ": "
                 << D.second.FileName << ", line:" << D.second.Line << "\n";
        }
      }
    }
  }

  return 0;
}

static void doPreallocation(TrivialMemoryManager &MemMgr) {
  // Allocate a slab of memory upfront, if required. This is used if
  // we want to test small code models.
  if (static_cast<intptr_t>(PreallocMemory) < 0)
    report_fatal_error("Pre-allocated bytes of memory must be a positive integer.");

  // FIXME: Limit the amount of memory that can be preallocated?
  if (PreallocMemory != 0)
    MemMgr.preallocateSlab(PreallocMemory);
}

static int executeInput() {
  // Load any dylibs requested on the command line.
  loadDylibs();

  // Instantiate a dynamic linker.
  TrivialMemoryManager MemMgr;
  doPreallocation(MemMgr);
  RuntimeDyld Dyld(MemMgr, MemMgr);

  // If we don't have any input files, read from stdin.
  if (!InputFileList.size())
    InputFileList.push_back("-");
  {
    TimeRegion TR(Timers ? &Timers->LoadObjectsTimer : nullptr);
    for (auto &File : InputFileList) {
      // Load the input memory buffer.
      ErrorOr<std::unique_ptr<MemoryBuffer>> InputBuffer =
          MemoryBuffer::getFileOrSTDIN(File);
      if (std::error_code EC = InputBuffer.getError())
        ErrorAndExit("unable to read input: '" + EC.message() + "'");
      Expected<std::unique_ptr<ObjectFile>> MaybeObj(
          ObjectFile::createObjectFile((*InputBuffer)->getMemBufferRef()));

      if (!MaybeObj) {
        std::string Buf;
        raw_string_ostream OS(Buf);
        logAllUnhandledErrors(MaybeObj.takeError(), OS);
        OS.flush();
        ErrorAndExit("unable to create object file: '" + Buf + "'");
      }

      ObjectFile &Obj = **MaybeObj;

      // Load the object file
      Dyld.loadObject(Obj);
      if (Dyld.hasError()) {
        ErrorAndExit(Dyld.getErrorString());
      }
    }
  }

  {
    TimeRegion TR(Timers ? &Timers->LinkTimer : nullptr);
    // Resove all the relocations we can.
    // FIXME: Error out if there are unresolved relocations.
    Dyld.resolveRelocations();
  }

  // Get the address of the entry point (_main by default).
  void *MainAddress = Dyld.getSymbolLocalAddress(EntryPoint);
  if (!MainAddress)
    ErrorAndExit("no definition for '" + EntryPoint + "'");

  // Invalidate the instruction cache for each loaded function.
  for (auto &FM : MemMgr.FunctionMemory) {

    auto &FM_MB = FM.MB;

    // Make sure the memory is executable.
    // setExecutable will call InvalidateInstructionCache.
    if (auto EC = sys::Memory::protectMappedMemory(FM_MB,
                                                   sys::Memory::MF_READ |
                                                   sys::Memory::MF_EXEC))
      ErrorAndExit("unable to mark function executable: '" + EC.message() +
                   "'");
  }

  // Dispatch to _main().
  errs() << "loaded '" << EntryPoint << "' at: " << (void*)MainAddress << "\n";

  int (*Main)(int, const char**) =
    (int(*)(int,const char**)) uintptr_t(MainAddress);
  std::vector<const char *> Argv;
  // Use the name of the first input object module as argv[0] for the target.
  Argv.push_back(InputFileList[0].data());
  for (auto &Arg : InputArgv)
    Argv.push_back(Arg.data());
  Argv.push_back(nullptr);
  int Result = 0;
  {
    TimeRegion TR(Timers ? &Timers->RunTimer : nullptr);
    Result = Main(Argv.size() - 1, Argv.data());
  }

  return Result;
}

static int checkAllExpressions(RuntimeDyldChecker &Checker) {
  for (const auto& CheckerFileName : CheckFiles) {
    ErrorOr<std::unique_ptr<MemoryBuffer>> CheckerFileBuf =
        MemoryBuffer::getFileOrSTDIN(CheckerFileName);
    if (std::error_code EC = CheckerFileBuf.getError())
      ErrorAndExit("unable to read input '" + CheckerFileName + "': " +
                   EC.message());

    if (!Checker.checkAllRulesInBuffer("# rtdyld-check:",
                                       CheckerFileBuf.get().get()))
      ErrorAndExit("some checks in '" + CheckerFileName + "' failed");
  }
  return 0;
}

void applySpecificSectionMappings(RuntimeDyld &Dyld,
                                  const FileToSectionIDMap &FileToSecIDMap) {

  for (StringRef Mapping : SpecificSectionMappings) {
    size_t EqualsIdx = Mapping.find_first_of("=");
    std::string SectionIDStr = std::string(Mapping.substr(0, EqualsIdx));
    size_t ComaIdx = Mapping.find_first_of(",");

    if (ComaIdx == StringRef::npos)
      report_fatal_error("Invalid section specification '" + Mapping +
                         "'. Should be '<file name>,<section name>=<addr>'");

    std::string FileName = SectionIDStr.substr(0, ComaIdx);
    std::string SectionName = SectionIDStr.substr(ComaIdx + 1);
    unsigned SectionID =
      ExitOnErr(getSectionId(FileToSecIDMap, FileName, SectionName));

    auto* OldAddr = Dyld.getSectionContent(SectionID).data();
    std::string NewAddrStr = std::string(Mapping.substr(EqualsIdx + 1));
    uint64_t NewAddr;

    if (StringRef(NewAddrStr).getAsInteger(0, NewAddr))
      report_fatal_error("Invalid section address in mapping '" + Mapping +
                         "'.");

    Dyld.mapSectionAddress(OldAddr, NewAddr);
  }
}

// Scatter sections in all directions!
// Remaps section addresses for -verify mode. The following command line options
// can be used to customize the layout of the memory within the phony target's
// address space:
// -target-addr-start <s> -- Specify where the phony target address range starts.
// -target-addr-end   <e> -- Specify where the phony target address range ends.
// -target-section-sep <d> -- Specify how big a gap should be left between the
//                            end of one section and the start of the next.
//                            Defaults to zero. Set to something big
//                            (e.g. 1 << 32) to stress-test stubs, GOTs, etc.
//
static void remapSectionsAndSymbols(const llvm::Triple &TargetTriple,
                                    RuntimeDyld &Dyld,
                                    TrivialMemoryManager &MemMgr) {

  // Set up a work list (section addr/size pairs).
  typedef std::list<const TrivialMemoryManager::SectionInfo*> WorklistT;
  WorklistT Worklist;

  for (const auto& CodeSection : MemMgr.FunctionMemory)
    Worklist.push_back(&CodeSection);
  for (const auto& DataSection : MemMgr.DataMemory)
    Worklist.push_back(&DataSection);

  // Keep an "already allocated" mapping of section target addresses to sizes.
  // Sections whose address mappings aren't specified on the command line will
  // allocated around the explicitly mapped sections while maintaining the
  // minimum separation.
  std::map<uint64_t, uint64_t> AlreadyAllocated;

  // Move the previously applied mappings (whether explicitly specified on the
  // command line, or implicitly set by RuntimeDyld) into the already-allocated
  // map.
  for (WorklistT::iterator I = Worklist.begin(), E = Worklist.end();
       I != E;) {
    WorklistT::iterator Tmp = I;
    ++I;

    auto LoadAddr = Dyld.getSectionLoadAddress((*Tmp)->SectionID);

    if (LoadAddr != static_cast<uint64_t>(
          reinterpret_cast<uintptr_t>((*Tmp)->MB.base()))) {
      // A section will have a LoadAddr of 0 if it wasn't loaded for whatever
      // reason (e.g. zero byte COFF sections). Don't include those sections in
      // the allocation map.
      if (LoadAddr != 0)
        AlreadyAllocated[LoadAddr] = (*Tmp)->MB.allocatedSize();
      Worklist.erase(Tmp);
    }
  }

  // If the -target-addr-end option wasn't explicitly passed, then set it to a
  // sensible default based on the target triple.
  if (TargetAddrEnd.getNumOccurrences() == 0) {
    if (TargetTriple.isArch16Bit())
      TargetAddrEnd = (1ULL << 16) - 1;
    else if (TargetTriple.isArch32Bit())
      TargetAddrEnd = (1ULL << 32) - 1;
    // TargetAddrEnd already has a sensible default for 64-bit systems, so
    // there's nothing to do in the 64-bit case.
  }

  // Process any elements remaining in the worklist.
  while (!Worklist.empty()) {
    auto *CurEntry = Worklist.front();
    Worklist.pop_front();

    uint64_t NextSectionAddr = TargetAddrStart;

    for (const auto &Alloc : AlreadyAllocated)
      if (NextSectionAddr + CurEntry->MB.allocatedSize() + TargetSectionSep <=
          Alloc.first)
        break;
      else
        NextSectionAddr = Alloc.first + Alloc.second + TargetSectionSep;

    Dyld.mapSectionAddress(CurEntry->MB.base(), NextSectionAddr);
    AlreadyAllocated[NextSectionAddr] = CurEntry->MB.allocatedSize();
  }

  // Add dummy symbols to the memory manager.
  for (const auto &Mapping : DummySymbolMappings) {
    size_t EqualsIdx = Mapping.find_first_of('=');

    if (EqualsIdx == StringRef::npos)
      report_fatal_error("Invalid dummy symbol specification '" + Mapping +
                         "'. Should be '<symbol name>=<addr>'");

    std::string Symbol = Mapping.substr(0, EqualsIdx);
    std::string AddrStr = Mapping.substr(EqualsIdx + 1);

    uint64_t Addr;
    if (StringRef(AddrStr).getAsInteger(0, Addr))
      report_fatal_error("Invalid symbol mapping '" + Mapping + "'.");

    MemMgr.addDummySymbol(Symbol, Addr);
  }
}

// Load and link the objects specified on the command line, but do not execute
// anything. Instead, attach a RuntimeDyldChecker instance and call it to
// verify the correctness of the linked memory.
static int linkAndVerify() {

  // Check for missing triple.
  if (TripleName == "")
    ErrorAndExit("-triple required when running in -verify mode.");

  // Look up the target and build the disassembler.
  Triple TheTriple(Triple::normalize(TripleName));
  std::string ErrorStr;
  const Target *TheTarget =
    TargetRegistry::lookupTarget("", TheTriple, ErrorStr);
  if (!TheTarget)
    ErrorAndExit("Error accessing target '" + TripleName + "': " + ErrorStr);

  TripleName = TheTriple.getTriple();

  std::unique_ptr<MCSubtargetInfo> STI(
    TheTarget->createMCSubtargetInfo(TripleName, MCPU, ""));
  if (!STI)
    ErrorAndExit("Unable to create subtarget info!");

  std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName));
  if (!MRI)
    ErrorAndExit("Unable to create target register info!");

  MCTargetOptions MCOptions;
  std::unique_ptr<MCAsmInfo> MAI(
      TheTarget->createMCAsmInfo(*MRI, TripleName, MCOptions));
  if (!MAI)
    ErrorAndExit("Unable to create target asm info!");

  MCContext Ctx(MAI.get(), MRI.get(), nullptr);

  std::unique_ptr<MCDisassembler> Disassembler(
    TheTarget->createMCDisassembler(*STI, Ctx));
  if (!Disassembler)
    ErrorAndExit("Unable to create disassembler!");

  std::unique_ptr<MCInstrInfo> MII(TheTarget->createMCInstrInfo());

  std::unique_ptr<MCInstPrinter> InstPrinter(
      TheTarget->createMCInstPrinter(Triple(TripleName), 0, *MAI, *MII, *MRI));

  // Load any dylibs requested on the command line.
  loadDylibs();

  // Instantiate a dynamic linker.
  TrivialMemoryManager MemMgr;
  doPreallocation(MemMgr);

  struct StubID {
    unsigned SectionID;
    uint32_t Offset;
  };
  using StubInfos = StringMap<StubID>;
  using StubContainers = StringMap<StubInfos>;

  StubContainers StubMap;
  RuntimeDyld Dyld(MemMgr, MemMgr);
  Dyld.setProcessAllSections(true);

  Dyld.setNotifyStubEmitted([&StubMap](StringRef FilePath,
                                       StringRef SectionName,
                                       StringRef SymbolName, unsigned SectionID,
                                       uint32_t StubOffset) {
    std::string ContainerName =
        (sys::path::filename(FilePath) + "/" + SectionName).str();
    StubMap[ContainerName][SymbolName] = {SectionID, StubOffset};
  });

  auto GetSymbolInfo =
      [&Dyld, &MemMgr](
          StringRef Symbol) -> Expected<RuntimeDyldChecker::MemoryRegionInfo> {
    RuntimeDyldChecker::MemoryRegionInfo SymInfo;

    // First get the target address.
    if (auto InternalSymbol = Dyld.getSymbol(Symbol))
      SymInfo.setTargetAddress(InternalSymbol.getAddress());
    else {
      // Symbol not found in RuntimeDyld. Fall back to external lookup.
#ifdef _MSC_VER
      using ExpectedLookupResult =
          MSVCPExpected<JITSymbolResolver::LookupResult>;
#else
      using ExpectedLookupResult = Expected<JITSymbolResolver::LookupResult>;
#endif

      auto ResultP = std::make_shared<std::promise<ExpectedLookupResult>>();
      auto ResultF = ResultP->get_future();

      MemMgr.lookup(JITSymbolResolver::LookupSet({Symbol}),
                    [=](Expected<JITSymbolResolver::LookupResult> Result) {
                      ResultP->set_value(std::move(Result));
                    });

      auto Result = ResultF.get();
      if (!Result)
        return Result.takeError();

      auto I = Result->find(Symbol);
      assert(I != Result->end() &&
             "Expected symbol address if no error occurred");
      SymInfo.setTargetAddress(I->second.getAddress());
    }

    // Now find the symbol content if possible (otherwise leave content as a
    // default-constructed StringRef).
    if (auto *SymAddr = Dyld.getSymbolLocalAddress(Symbol)) {
      unsigned SectionID = Dyld.getSymbolSectionID(Symbol);
      if (SectionID != ~0U) {
        char *CSymAddr = static_cast<char *>(SymAddr);
        StringRef SecContent = Dyld.getSectionContent(SectionID);
        uint64_t SymSize = SecContent.size() - (CSymAddr - SecContent.data());
        SymInfo.setContent(StringRef(CSymAddr, SymSize));
      }
    }
    return SymInfo;
  };

  auto IsSymbolValid = [&Dyld, GetSymbolInfo](StringRef Symbol) {
    if (Dyld.getSymbol(Symbol))
      return true;
    auto SymInfo = GetSymbolInfo(Symbol);
    if (!SymInfo) {
      logAllUnhandledErrors(SymInfo.takeError(), errs(), "RTDyldChecker: ");
      return false;
    }
    return SymInfo->getTargetAddress() != 0;
  };

  FileToSectionIDMap FileToSecIDMap;

  auto GetSectionInfo = [&Dyld, &FileToSecIDMap](StringRef FileName,
                                                 StringRef SectionName)
      -> Expected<RuntimeDyldChecker::MemoryRegionInfo> {
    auto SectionID = getSectionId(FileToSecIDMap, FileName, SectionName);
    if (!SectionID)
      return SectionID.takeError();
    RuntimeDyldChecker::MemoryRegionInfo SecInfo;
    SecInfo.setTargetAddress(Dyld.getSectionLoadAddress(*SectionID));
    SecInfo.setContent(Dyld.getSectionContent(*SectionID));
    return SecInfo;
  };

  auto GetStubInfo = [&Dyld, &StubMap](StringRef StubContainer,
                                       StringRef SymbolName)
      -> Expected<RuntimeDyldChecker::MemoryRegionInfo> {
    if (!StubMap.count(StubContainer))
      return make_error<StringError>("Stub container not found: " +
                                         StubContainer,
                                     inconvertibleErrorCode());
    if (!StubMap[StubContainer].count(SymbolName))
      return make_error<StringError>("Symbol name " + SymbolName +
                                         " in stub container " + StubContainer,
                                     inconvertibleErrorCode());
    auto &SI = StubMap[StubContainer][SymbolName];
    RuntimeDyldChecker::MemoryRegionInfo StubMemInfo;
    StubMemInfo.setTargetAddress(Dyld.getSectionLoadAddress(SI.SectionID) +
                                 SI.Offset);
    StubMemInfo.setContent(
        Dyld.getSectionContent(SI.SectionID).substr(SI.Offset));
    return StubMemInfo;
  };

  // We will initialize this below once we have the first object file and can
  // know the endianness.
  std::unique_ptr<RuntimeDyldChecker> Checker;

  // If we don't have any input files, read from stdin.
  if (!InputFileList.size())
    InputFileList.push_back("-");
  for (auto &InputFile : InputFileList) {
    // Load the input memory buffer.
    ErrorOr<std::unique_ptr<MemoryBuffer>> InputBuffer =
        MemoryBuffer::getFileOrSTDIN(InputFile);

    if (std::error_code EC = InputBuffer.getError())
      ErrorAndExit("unable to read input: '" + EC.message() + "'");

    Expected<std::unique_ptr<ObjectFile>> MaybeObj(
      ObjectFile::createObjectFile((*InputBuffer)->getMemBufferRef()));

    if (!MaybeObj) {
      std::string Buf;
      raw_string_ostream OS(Buf);
      logAllUnhandledErrors(MaybeObj.takeError(), OS);
      OS.flush();
      ErrorAndExit("unable to create object file: '" + Buf + "'");
    }

    ObjectFile &Obj = **MaybeObj;

    if (!Checker)
      Checker = std::make_unique<RuntimeDyldChecker>(
          IsSymbolValid, GetSymbolInfo, GetSectionInfo, GetStubInfo,
          GetStubInfo, Obj.isLittleEndian() ? support::little : support::big,
          Disassembler.get(), InstPrinter.get(), dbgs());

    auto FileName = sys::path::filename(InputFile);
    MemMgr.setSectionIDsMap(&FileToSecIDMap[FileName]);

    // Load the object file
    Dyld.loadObject(Obj);
    if (Dyld.hasError()) {
      ErrorAndExit(Dyld.getErrorString());
    }
  }

  // Re-map the section addresses into the phony target address space and add
  // dummy symbols.
  applySpecificSectionMappings(Dyld, FileToSecIDMap);
  remapSectionsAndSymbols(TheTriple, Dyld, MemMgr);

  // Resolve all the relocations we can.
  Dyld.resolveRelocations();

  // Register EH frames.
  Dyld.registerEHFrames();

  int ErrorCode = checkAllExpressions(*Checker);
  if (Dyld.hasError())
    ErrorAndExit("RTDyld reported an error applying relocations:\n  " +
                 Dyld.getErrorString());

  return ErrorCode;
}

int main(int argc, char **argv) {
  InitLLVM X(argc, argv);
  ProgramName = argv[0];

  llvm::InitializeAllTargetInfos();
  llvm::InitializeAllTargetMCs();
  llvm::InitializeAllDisassemblers();

  cl::ParseCommandLineOptions(argc, argv, "llvm MC-JIT tool\n");

  ExitOnErr.setBanner(std::string(argv[0]) + ": ");

  Timers = ShowTimes ? std::make_unique<RTDyldTimers>() : nullptr;

  int Result;
  switch (Action) {
  case AC_Execute:
    Result = executeInput();
    break;
  case AC_PrintDebugLineInfo:
    Result =
        printLineInfoForInput(/* LoadObjects */ true, /* UseDebugObj */ true);
    break;
  case AC_PrintLineInfo:
    Result =
        printLineInfoForInput(/* LoadObjects */ true, /* UseDebugObj */ false);
    break;
  case AC_PrintObjectLineInfo:
    Result =
        printLineInfoForInput(/* LoadObjects */ false, /* UseDebugObj */ false);
    break;
  case AC_Verify:
    Result = linkAndVerify();
    break;
  }
  return Result;
}