llvm.org GIT mirror llvm / bfd9349 lib / DebugInfo / DWARF / DWARFDebugLine.cpp
bfd9349

Tree @bfd9349 (Download .tar.gz)

DWARFDebugLine.cpp @bfd9349raw · history · blame

   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
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
//===- DWARFDebugLine.cpp -------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//

#include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
#include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/WithColor.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <cinttypes>
#include <cstdint>
#include <cstdio>
#include <utility>

using namespace llvm;
using namespace dwarf;

using FileLineInfoKind = DILineInfoSpecifier::FileLineInfoKind;

namespace {

struct ContentDescriptor {
  dwarf::LineNumberEntryFormat Type;
  dwarf::Form Form;
};

using ContentDescriptors = SmallVector<ContentDescriptor, 4>;

} // end anonmyous namespace

void DWARFDebugLine::ContentTypeTracker::trackContentType(
    dwarf::LineNumberEntryFormat ContentType) {
  switch (ContentType) {
  case dwarf::DW_LNCT_timestamp:
    HasModTime = true;
    break;
  case dwarf::DW_LNCT_size:
    HasLength = true;
    break;
  case dwarf::DW_LNCT_MD5:
    HasMD5 = true;
    break;
  case dwarf::DW_LNCT_LLVM_source:
    HasSource = true;
    break;
  default:
    // We only care about values we consider optional, and new values may be
    // added in the vendor extension range, so we do not match exhaustively.
    break;
  }
}

DWARFDebugLine::Prologue::Prologue() { clear(); }

bool DWARFDebugLine::Prologue::hasFileAtIndex(uint64_t FileIndex) const {
  uint16_t DwarfVersion = getVersion();
  assert(DwarfVersion != 0 &&
         "line table prologue has no dwarf version information");
  if (DwarfVersion >= 5)
    return FileIndex < FileNames.size();
  return FileIndex != 0 && FileIndex <= FileNames.size();
}

const llvm::DWARFDebugLine::FileNameEntry &
DWARFDebugLine::Prologue::getFileNameEntry(uint64_t Index) const {
  uint16_t DwarfVersion = getVersion();
  assert(DwarfVersion != 0 &&
         "line table prologue has no dwarf version information");
  // In DWARF v5 the file names are 0-indexed.
  if (DwarfVersion >= 5)
    return FileNames[Index];
  return FileNames[Index - 1];
}

void DWARFDebugLine::Prologue::clear() {
  TotalLength = PrologueLength = 0;
  SegSelectorSize = 0;
  MinInstLength = MaxOpsPerInst = DefaultIsStmt = LineBase = LineRange = 0;
  OpcodeBase = 0;
  FormParams = dwarf::FormParams({0, 0, DWARF32});
  ContentTypes = ContentTypeTracker();
  StandardOpcodeLengths.clear();
  IncludeDirectories.clear();
  FileNames.clear();
}

void DWARFDebugLine::Prologue::dump(raw_ostream &OS,
                                    DIDumpOptions DumpOptions) const {
  OS << "Line table prologue:\n"
     << format("    total_length: 0x%8.8" PRIx64 "\n", TotalLength)
     << format("         version: %u\n", getVersion());
  if (getVersion() >= 5)
    OS << format("    address_size: %u\n", getAddressSize())
       << format(" seg_select_size: %u\n", SegSelectorSize);
  OS << format(" prologue_length: 0x%8.8" PRIx64 "\n", PrologueLength)
     << format(" min_inst_length: %u\n", MinInstLength)
     << format(getVersion() >= 4 ? "max_ops_per_inst: %u\n" : "", MaxOpsPerInst)
     << format(" default_is_stmt: %u\n", DefaultIsStmt)
     << format("       line_base: %i\n", LineBase)
     << format("      line_range: %u\n", LineRange)
     << format("     opcode_base: %u\n", OpcodeBase);

  for (uint32_t I = 0; I != StandardOpcodeLengths.size(); ++I)
    OS << format("standard_opcode_lengths[%s] = %u\n",
                 LNStandardString(I + 1).data(), StandardOpcodeLengths[I]);

  if (!IncludeDirectories.empty()) {
    // DWARF v5 starts directory indexes at 0.
    uint32_t DirBase = getVersion() >= 5 ? 0 : 1;
    for (uint32_t I = 0; I != IncludeDirectories.size(); ++I) {
      OS << format("include_directories[%3u] = ", I + DirBase);
      IncludeDirectories[I].dump(OS, DumpOptions);
      OS << '\n';
    }
  }

  if (!FileNames.empty()) {
    // DWARF v5 starts file indexes at 0.
    uint32_t FileBase = getVersion() >= 5 ? 0 : 1;
    for (uint32_t I = 0; I != FileNames.size(); ++I) {
      const FileNameEntry &FileEntry = FileNames[I];
      OS <<   format("file_names[%3u]:\n", I + FileBase);
      OS <<          "           name: ";
      FileEntry.Name.dump(OS, DumpOptions);
      OS << '\n'
         <<   format("      dir_index: %" PRIu64 "\n", FileEntry.DirIdx);
      if (ContentTypes.HasMD5)
        OS <<        "   md5_checksum: " << FileEntry.Checksum.digest() << '\n';
      if (ContentTypes.HasModTime)
        OS << format("       mod_time: 0x%8.8" PRIx64 "\n", FileEntry.ModTime);
      if (ContentTypes.HasLength)
        OS << format("         length: 0x%8.8" PRIx64 "\n", FileEntry.Length);
      if (ContentTypes.HasSource) {
        OS <<        "         source: ";
        FileEntry.Source.dump(OS, DumpOptions);
        OS << '\n';
      }
    }
  }
}

// Parse v2-v4 directory and file tables.
static void
parseV2DirFileTables(const DWARFDataExtractor &DebugLineData,
                     uint32_t *OffsetPtr, uint64_t EndPrologueOffset,
                     DWARFDebugLine::ContentTypeTracker &ContentTypes,
                     std::vector<DWARFFormValue> &IncludeDirectories,
                     std::vector<DWARFDebugLine::FileNameEntry> &FileNames) {
  while (*OffsetPtr < EndPrologueOffset) {
    StringRef S = DebugLineData.getCStrRef(OffsetPtr);
    if (S.empty())
      break;
    DWARFFormValue Dir =
        DWARFFormValue::createFromPValue(dwarf::DW_FORM_string, S.data());
    IncludeDirectories.push_back(Dir);
  }

  while (*OffsetPtr < EndPrologueOffset) {
    StringRef Name = DebugLineData.getCStrRef(OffsetPtr);
    if (Name.empty())
      break;
    DWARFDebugLine::FileNameEntry FileEntry;
    FileEntry.Name =
        DWARFFormValue::createFromPValue(dwarf::DW_FORM_string, Name.data());
    FileEntry.DirIdx = DebugLineData.getULEB128(OffsetPtr);
    FileEntry.ModTime = DebugLineData.getULEB128(OffsetPtr);
    FileEntry.Length = DebugLineData.getULEB128(OffsetPtr);
    FileNames.push_back(FileEntry);
  }

  ContentTypes.HasModTime = true;
  ContentTypes.HasLength = true;
}

// Parse v5 directory/file entry content descriptions.
// Returns the descriptors, or an empty vector if we did not find a path or
// ran off the end of the prologue.
static ContentDescriptors
parseV5EntryFormat(const DWARFDataExtractor &DebugLineData, uint32_t
    *OffsetPtr, uint64_t EndPrologueOffset, DWARFDebugLine::ContentTypeTracker
    *ContentTypes) {
  ContentDescriptors Descriptors;
  int FormatCount = DebugLineData.getU8(OffsetPtr);
  bool HasPath = false;
  for (int I = 0; I != FormatCount; ++I) {
    if (*OffsetPtr >= EndPrologueOffset)
      return ContentDescriptors();
    ContentDescriptor Descriptor;
    Descriptor.Type =
      dwarf::LineNumberEntryFormat(DebugLineData.getULEB128(OffsetPtr));
    Descriptor.Form = dwarf::Form(DebugLineData.getULEB128(OffsetPtr));
    if (Descriptor.Type == dwarf::DW_LNCT_path)
      HasPath = true;
    if (ContentTypes)
      ContentTypes->trackContentType(Descriptor.Type);
    Descriptors.push_back(Descriptor);
  }
  return HasPath ? Descriptors : ContentDescriptors();
}

static bool
parseV5DirFileTables(const DWARFDataExtractor &DebugLineData,
                     uint32_t *OffsetPtr, uint64_t EndPrologueOffset,
                     const dwarf::FormParams &FormParams,
                     const DWARFContext &Ctx, const DWARFUnit *U,
                     DWARFDebugLine::ContentTypeTracker &ContentTypes,
                     std::vector<DWARFFormValue> &IncludeDirectories,
                     std::vector<DWARFDebugLine::FileNameEntry> &FileNames) {
  // Get the directory entry description.
  ContentDescriptors DirDescriptors =
      parseV5EntryFormat(DebugLineData, OffsetPtr, EndPrologueOffset, nullptr);
  if (DirDescriptors.empty())
    return false;

  // Get the directory entries, according to the format described above.
  int DirEntryCount = DebugLineData.getU8(OffsetPtr);
  for (int I = 0; I != DirEntryCount; ++I) {
    if (*OffsetPtr >= EndPrologueOffset)
      return false;
    for (auto Descriptor : DirDescriptors) {
      DWARFFormValue Value(Descriptor.Form);
      switch (Descriptor.Type) {
      case DW_LNCT_path:
        if (!Value.extractValue(DebugLineData, OffsetPtr, FormParams, &Ctx, U))
          return false;
        IncludeDirectories.push_back(Value);
        break;
      default:
        if (!Value.skipValue(DebugLineData, OffsetPtr, FormParams))
          return false;
      }
    }
  }

  // Get the file entry description.
  ContentDescriptors FileDescriptors =
      parseV5EntryFormat(DebugLineData, OffsetPtr, EndPrologueOffset,
          &ContentTypes);
  if (FileDescriptors.empty())
    return false;

  // Get the file entries, according to the format described above.
  int FileEntryCount = DebugLineData.getU8(OffsetPtr);
  for (int I = 0; I != FileEntryCount; ++I) {
    if (*OffsetPtr >= EndPrologueOffset)
      return false;
    DWARFDebugLine::FileNameEntry FileEntry;
    for (auto Descriptor : FileDescriptors) {
      DWARFFormValue Value(Descriptor.Form);
      if (!Value.extractValue(DebugLineData, OffsetPtr, FormParams, &Ctx, U))
        return false;
      switch (Descriptor.Type) {
      case DW_LNCT_path:
        FileEntry.Name = Value;
        break;
      case DW_LNCT_LLVM_source:
        FileEntry.Source = Value;
        break;
      case DW_LNCT_directory_index:
        FileEntry.DirIdx = Value.getAsUnsignedConstant().getValue();
        break;
      case DW_LNCT_timestamp:
        FileEntry.ModTime = Value.getAsUnsignedConstant().getValue();
        break;
      case DW_LNCT_size:
        FileEntry.Length = Value.getAsUnsignedConstant().getValue();
        break;
      case DW_LNCT_MD5:
        assert(Value.getAsBlock().getValue().size() == 16);
        std::uninitialized_copy_n(Value.getAsBlock().getValue().begin(), 16,
                                  FileEntry.Checksum.Bytes.begin());
        break;
      default:
        break;
      }
    }
    FileNames.push_back(FileEntry);
  }
  return true;
}

Error DWARFDebugLine::Prologue::parse(const DWARFDataExtractor &DebugLineData,
                                      uint32_t *OffsetPtr,
                                      const DWARFContext &Ctx,
                                      const DWARFUnit *U) {
  const uint64_t PrologueOffset = *OffsetPtr;

  clear();
  TotalLength = DebugLineData.getRelocatedValue(4, OffsetPtr);
  if (TotalLength == UINT32_MAX) {
    FormParams.Format = dwarf::DWARF64;
    TotalLength = DebugLineData.getU64(OffsetPtr);
  } else if (TotalLength >= 0xfffffff0) {
    return createStringError(errc::invalid_argument,
        "parsing line table prologue at offset 0x%8.8" PRIx64
        " unsupported reserved unit length found of value 0x%8.8" PRIx64,
        PrologueOffset, TotalLength);
  }
  FormParams.Version = DebugLineData.getU16(OffsetPtr);
  if (getVersion() < 2)
    return createStringError(errc::not_supported,
                       "parsing line table prologue at offset 0x%8.8" PRIx64
                       " found unsupported version 0x%2.2" PRIx16,
                       PrologueOffset, getVersion());

  if (getVersion() >= 5) {
    FormParams.AddrSize = DebugLineData.getU8(OffsetPtr);
    assert((DebugLineData.getAddressSize() == 0 ||
            DebugLineData.getAddressSize() == getAddressSize()) &&
           "Line table header and data extractor disagree");
    SegSelectorSize = DebugLineData.getU8(OffsetPtr);
  }

  PrologueLength =
      DebugLineData.getRelocatedValue(sizeofPrologueLength(), OffsetPtr);
  const uint64_t EndPrologueOffset = PrologueLength + *OffsetPtr;
  MinInstLength = DebugLineData.getU8(OffsetPtr);
  if (getVersion() >= 4)
    MaxOpsPerInst = DebugLineData.getU8(OffsetPtr);
  DefaultIsStmt = DebugLineData.getU8(OffsetPtr);
  LineBase = DebugLineData.getU8(OffsetPtr);
  LineRange = DebugLineData.getU8(OffsetPtr);
  OpcodeBase = DebugLineData.getU8(OffsetPtr);

  StandardOpcodeLengths.reserve(OpcodeBase - 1);
  for (uint32_t I = 1; I < OpcodeBase; ++I) {
    uint8_t OpLen = DebugLineData.getU8(OffsetPtr);
    StandardOpcodeLengths.push_back(OpLen);
  }

  if (getVersion() >= 5) {
    if (!parseV5DirFileTables(DebugLineData, OffsetPtr, EndPrologueOffset,
                              FormParams, Ctx, U, ContentTypes,
                              IncludeDirectories, FileNames)) {
      return createStringError(errc::invalid_argument,
          "parsing line table prologue at 0x%8.8" PRIx64
          " found an invalid directory or file table description at"
          " 0x%8.8" PRIx64,
          PrologueOffset, (uint64_t)*OffsetPtr);
    }
  } else
    parseV2DirFileTables(DebugLineData, OffsetPtr, EndPrologueOffset,
                         ContentTypes, IncludeDirectories, FileNames);

  if (*OffsetPtr != EndPrologueOffset)
    return createStringError(errc::invalid_argument,
                       "parsing line table prologue at 0x%8.8" PRIx64
                       " should have ended at 0x%8.8" PRIx64
                       " but it ended at 0x%8.8" PRIx64,
                       PrologueOffset, EndPrologueOffset, (uint64_t)*OffsetPtr);
  return Error::success();
}

DWARFDebugLine::Row::Row(bool DefaultIsStmt) { reset(DefaultIsStmt); }

void DWARFDebugLine::Row::postAppend() {
  Discriminator = 0;
  BasicBlock = false;
  PrologueEnd = false;
  EpilogueBegin = false;
}

void DWARFDebugLine::Row::reset(bool DefaultIsStmt) {
  Address.Address = 0;
  Address.SectionIndex = object::SectionedAddress::UndefSection;
  Line = 1;
  Column = 0;
  File = 1;
  Isa = 0;
  Discriminator = 0;
  IsStmt = DefaultIsStmt;
  BasicBlock = false;
  EndSequence = false;
  PrologueEnd = false;
  EpilogueBegin = false;
}

void DWARFDebugLine::Row::dumpTableHeader(raw_ostream &OS) {
  OS << "Address            Line   Column File   ISA Discriminator Flags\n"
     << "------------------ ------ ------ ------ --- ------------- "
        "-------------\n";
}

void DWARFDebugLine::Row::dump(raw_ostream &OS) const {
  OS << format("0x%16.16" PRIx64 " %6u %6u", Address.Address, Line, Column)
     << format(" %6u %3u %13u ", File, Isa, Discriminator)
     << (IsStmt ? " is_stmt" : "") << (BasicBlock ? " basic_block" : "")
     << (PrologueEnd ? " prologue_end" : "")
     << (EpilogueBegin ? " epilogue_begin" : "")
     << (EndSequence ? " end_sequence" : "") << '\n';
}

DWARFDebugLine::Sequence::Sequence() { reset(); }

void DWARFDebugLine::Sequence::reset() {
  LowPC = 0;
  HighPC = 0;
  SectionIndex = object::SectionedAddress::UndefSection;
  FirstRowIndex = 0;
  LastRowIndex = 0;
  Empty = true;
}

DWARFDebugLine::LineTable::LineTable() { clear(); }

void DWARFDebugLine::LineTable::dump(raw_ostream &OS,
                                     DIDumpOptions DumpOptions) const {
  Prologue.dump(OS, DumpOptions);
  OS << '\n';

  if (!Rows.empty()) {
    Row::dumpTableHeader(OS);
    for (const Row &R : Rows) {
      R.dump(OS);
    }
  }
}

void DWARFDebugLine::LineTable::clear() {
  Prologue.clear();
  Rows.clear();
  Sequences.clear();
}

DWARFDebugLine::ParsingState::ParsingState(struct LineTable *LT)
    : LineTable(LT) {
  resetRowAndSequence();
}

void DWARFDebugLine::ParsingState::resetRowAndSequence() {
  Row.reset(LineTable->Prologue.DefaultIsStmt);
  Sequence.reset();
}

void DWARFDebugLine::ParsingState::appendRowToMatrix() {
  unsigned RowNumber = LineTable->Rows.size();
  if (Sequence.Empty) {
    // Record the beginning of instruction sequence.
    Sequence.Empty = false;
    Sequence.LowPC = Row.Address.Address;
    Sequence.FirstRowIndex = RowNumber;
  }
  LineTable->appendRow(Row);
  if (Row.EndSequence) {
    // Record the end of instruction sequence.
    Sequence.HighPC = Row.Address.Address;
    Sequence.LastRowIndex = RowNumber + 1;
    Sequence.SectionIndex = Row.Address.SectionIndex;
    if (Sequence.isValid())
      LineTable->appendSequence(Sequence);
    Sequence.reset();
  }
  Row.postAppend();
}

const DWARFDebugLine::LineTable *
DWARFDebugLine::getLineTable(uint32_t Offset) const {
  LineTableConstIter Pos = LineTableMap.find(Offset);
  if (Pos != LineTableMap.end())
    return &Pos->second;
  return nullptr;
}

Expected<const DWARFDebugLine::LineTable *> DWARFDebugLine::getOrParseLineTable(
    DWARFDataExtractor &DebugLineData, uint32_t Offset, const DWARFContext &Ctx,
    const DWARFUnit *U, std::function<void(Error)> RecoverableErrorCallback) {
  if (!DebugLineData.isValidOffset(Offset))
    return createStringError(errc::invalid_argument, "offset 0x%8.8" PRIx32
                       " is not a valid debug line section offset",
                       Offset);

  std::pair<LineTableIter, bool> Pos =
      LineTableMap.insert(LineTableMapTy::value_type(Offset, LineTable()));
  LineTable *LT = &Pos.first->second;
  if (Pos.second) {
    if (Error Err =
            LT->parse(DebugLineData, &Offset, Ctx, U, RecoverableErrorCallback))
      return std::move(Err);
    return LT;
  }
  return LT;
}

Error DWARFDebugLine::LineTable::parse(
    DWARFDataExtractor &DebugLineData, uint32_t *OffsetPtr,
    const DWARFContext &Ctx, const DWARFUnit *U,
    std::function<void(Error)> RecoverableErrorCallback, raw_ostream *OS) {
  const uint32_t DebugLineOffset = *OffsetPtr;

  clear();

  Error PrologueErr = Prologue.parse(DebugLineData, OffsetPtr, Ctx, U);

  if (OS) {
    // The presence of OS signals verbose dumping.
    DIDumpOptions DumpOptions;
    DumpOptions.Verbose = true;
    Prologue.dump(*OS, DumpOptions);
  }

  if (PrologueErr)
    return PrologueErr;

  const uint32_t EndOffset =
      DebugLineOffset + Prologue.TotalLength + Prologue.sizeofTotalLength();

  // See if we should tell the data extractor the address size.
  if (DebugLineData.getAddressSize() == 0)
    DebugLineData.setAddressSize(Prologue.getAddressSize());
  else
    assert(Prologue.getAddressSize() == 0 ||
           Prologue.getAddressSize() == DebugLineData.getAddressSize());

  ParsingState State(this);

  while (*OffsetPtr < EndOffset) {
    if (OS)
      *OS << format("0x%08.08" PRIx32 ": ", *OffsetPtr);

    uint8_t Opcode = DebugLineData.getU8(OffsetPtr);

    if (OS)
      *OS << format("%02.02" PRIx8 " ", Opcode);

    if (Opcode == 0) {
      // Extended Opcodes always start with a zero opcode followed by
      // a uleb128 length so you can skip ones you don't know about
      uint64_t Len = DebugLineData.getULEB128(OffsetPtr);
      uint32_t ExtOffset = *OffsetPtr;

      // Tolerate zero-length; assume length is correct and soldier on.
      if (Len == 0) {
        if (OS)
          *OS << "Badly formed extended line op (length 0)\n";
        continue;
      }

      uint8_t SubOpcode = DebugLineData.getU8(OffsetPtr);
      if (OS)
        *OS << LNExtendedString(SubOpcode);
      switch (SubOpcode) {
      case DW_LNE_end_sequence:
        // Set the end_sequence register of the state machine to true and
        // append a row to the matrix using the current values of the
        // state-machine registers. Then reset the registers to the initial
        // values specified above. Every statement program sequence must end
        // with a DW_LNE_end_sequence instruction which creates a row whose
        // address is that of the byte after the last target machine instruction
        // of the sequence.
        State.Row.EndSequence = true;
        State.appendRowToMatrix();
        if (OS) {
          *OS << "\n";
          OS->indent(12);
          State.Row.dump(*OS);
        }
        State.resetRowAndSequence();
        break;

      case DW_LNE_set_address:
        // Takes a single relocatable address as an operand. The size of the
        // operand is the size appropriate to hold an address on the target
        // machine. Set the address register to the value given by the
        // relocatable address. All of the other statement program opcodes
        // that affect the address register add a delta to it. This instruction
        // stores a relocatable value into it instead.
        //
        // Make sure the extractor knows the address size.  If not, infer it
        // from the size of the operand.
        if (DebugLineData.getAddressSize() == 0)
          DebugLineData.setAddressSize(Len - 1);
        else if (DebugLineData.getAddressSize() != Len - 1) {
          return createStringError(errc::invalid_argument,
                             "mismatching address size at offset 0x%8.8" PRIx32
                             " expected 0x%2.2" PRIx8 " found 0x%2.2" PRIx64,
                             ExtOffset, DebugLineData.getAddressSize(),
                             Len - 1);
        }
        State.Row.Address.Address = DebugLineData.getRelocatedAddress(
            OffsetPtr, &State.Row.Address.SectionIndex);
        if (OS)
          *OS << format(" (0x%16.16" PRIx64 ")", State.Row.Address.Address);
        break;

      case DW_LNE_define_file:
        // Takes 4 arguments. The first is a null terminated string containing
        // a source file name. The second is an unsigned LEB128 number
        // representing the directory index of the directory in which the file
        // was found. The third is an unsigned LEB128 number representing the
        // time of last modification of the file. The fourth is an unsigned
        // LEB128 number representing the length in bytes of the file. The time
        // and length fields may contain LEB128(0) if the information is not
        // available.
        //
        // The directory index represents an entry in the include_directories
        // section of the statement program prologue. The index is LEB128(0)
        // if the file was found in the current directory of the compilation,
        // LEB128(1) if it was found in the first directory in the
        // include_directories section, and so on. The directory index is
        // ignored for file names that represent full path names.
        //
        // The files are numbered, starting at 1, in the order in which they
        // appear; the names in the prologue come before names defined by
        // the DW_LNE_define_file instruction. These numbers are used in the
        // the file register of the state machine.
        {
          FileNameEntry FileEntry;
          const char *Name = DebugLineData.getCStr(OffsetPtr);
          FileEntry.Name =
              DWARFFormValue::createFromPValue(dwarf::DW_FORM_string, Name);
          FileEntry.DirIdx = DebugLineData.getULEB128(OffsetPtr);
          FileEntry.ModTime = DebugLineData.getULEB128(OffsetPtr);
          FileEntry.Length = DebugLineData.getULEB128(OffsetPtr);
          Prologue.FileNames.push_back(FileEntry);
          if (OS)
            *OS << " (" << Name << ", dir=" << FileEntry.DirIdx << ", mod_time="
                << format("(0x%16.16" PRIx64 ")", FileEntry.ModTime)
                << ", length=" << FileEntry.Length << ")";
        }
        break;

      case DW_LNE_set_discriminator:
        State.Row.Discriminator = DebugLineData.getULEB128(OffsetPtr);
        if (OS)
          *OS << " (" << State.Row.Discriminator << ")";
        break;

      default:
        if (OS)
          *OS << format("Unrecognized extended op 0x%02.02" PRIx8, SubOpcode)
              << format(" length %" PRIx64, Len);
        // Len doesn't include the zero opcode byte or the length itself, but
        // it does include the sub_opcode, so we have to adjust for that.
        (*OffsetPtr) += Len - 1;
        break;
      }
      // Make sure the stated and parsed lengths are the same.
      // Otherwise we have an unparseable line-number program.
      if (*OffsetPtr - ExtOffset != Len)
        return createStringError(errc::illegal_byte_sequence,
                           "unexpected line op length at offset 0x%8.8" PRIx32
                           " expected 0x%2.2" PRIx64 " found 0x%2.2" PRIx32,
                           ExtOffset, Len, *OffsetPtr - ExtOffset);
    } else if (Opcode < Prologue.OpcodeBase) {
      if (OS)
        *OS << LNStandardString(Opcode);
      switch (Opcode) {
      // Standard Opcodes
      case DW_LNS_copy:
        // Takes no arguments. Append a row to the matrix using the
        // current values of the state-machine registers.
        if (OS) {
          *OS << "\n";
          OS->indent(12);
          State.Row.dump(*OS);
          *OS << "\n";
        }
        State.appendRowToMatrix();
        break;

      case DW_LNS_advance_pc:
        // Takes a single unsigned LEB128 operand, multiplies it by the
        // min_inst_length field of the prologue, and adds the
        // result to the address register of the state machine.
        {
          uint64_t AddrOffset =
              DebugLineData.getULEB128(OffsetPtr) * Prologue.MinInstLength;
          State.Row.Address.Address += AddrOffset;
          if (OS)
            *OS << " (" << AddrOffset << ")";
        }
        break;

      case DW_LNS_advance_line:
        // Takes a single signed LEB128 operand and adds that value to
        // the line register of the state machine.
        State.Row.Line += DebugLineData.getSLEB128(OffsetPtr);
        if (OS)
          *OS << " (" << State.Row.Line << ")";
        break;

      case DW_LNS_set_file:
        // Takes a single unsigned LEB128 operand and stores it in the file
        // register of the state machine.
        State.Row.File = DebugLineData.getULEB128(OffsetPtr);
        if (OS)
          *OS << " (" << State.Row.File << ")";
        break;

      case DW_LNS_set_column:
        // Takes a single unsigned LEB128 operand and stores it in the
        // column register of the state machine.
        State.Row.Column = DebugLineData.getULEB128(OffsetPtr);
        if (OS)
          *OS << " (" << State.Row.Column << ")";
        break;

      case DW_LNS_negate_stmt:
        // Takes no arguments. Set the is_stmt register of the state
        // machine to the logical negation of its current value.
        State.Row.IsStmt = !State.Row.IsStmt;
        break;

      case DW_LNS_set_basic_block:
        // Takes no arguments. Set the basic_block register of the
        // state machine to true
        State.Row.BasicBlock = true;
        break;

      case DW_LNS_const_add_pc:
        // Takes no arguments. Add to the address register of the state
        // machine the address increment value corresponding to special
        // opcode 255. The motivation for DW_LNS_const_add_pc is this:
        // when the statement program needs to advance the address by a
        // small amount, it can use a single special opcode, which occupies
        // a single byte. When it needs to advance the address by up to
        // twice the range of the last special opcode, it can use
        // DW_LNS_const_add_pc followed by a special opcode, for a total
        // of two bytes. Only if it needs to advance the address by more
        // than twice that range will it need to use both DW_LNS_advance_pc
        // and a special opcode, requiring three or more bytes.
        {
          uint8_t AdjustOpcode = 255 - Prologue.OpcodeBase;
          uint64_t AddrOffset =
              (AdjustOpcode / Prologue.LineRange) * Prologue.MinInstLength;
          State.Row.Address.Address += AddrOffset;
          if (OS)
            *OS
                << format(" (0x%16.16" PRIx64 ")", AddrOffset);
        }
        break;

      case DW_LNS_fixed_advance_pc:
        // Takes a single uhalf operand. Add to the address register of
        // the state machine the value of the (unencoded) operand. This
        // is the only extended opcode that takes an argument that is not
        // a variable length number. The motivation for DW_LNS_fixed_advance_pc
        // is this: existing assemblers cannot emit DW_LNS_advance_pc or
        // special opcodes because they cannot encode LEB128 numbers or
        // judge when the computation of a special opcode overflows and
        // requires the use of DW_LNS_advance_pc. Such assemblers, however,
        // can use DW_LNS_fixed_advance_pc instead, sacrificing compression.
        {
          uint16_t PCOffset = DebugLineData.getRelocatedValue(2, OffsetPtr);
          State.Row.Address.Address += PCOffset;
          if (OS)
            *OS
                << format(" (0x%4.4" PRIx16 ")", PCOffset);
        }
        break;

      case DW_LNS_set_prologue_end:
        // Takes no arguments. Set the prologue_end register of the
        // state machine to true
        State.Row.PrologueEnd = true;
        break;

      case DW_LNS_set_epilogue_begin:
        // Takes no arguments. Set the basic_block register of the
        // state machine to true
        State.Row.EpilogueBegin = true;
        break;

      case DW_LNS_set_isa:
        // Takes a single unsigned LEB128 operand and stores it in the
        // column register of the state machine.
        State.Row.Isa = DebugLineData.getULEB128(OffsetPtr);
        if (OS)
          *OS << " (" << State.Row.Isa << ")";
        break;

      default:
        // Handle any unknown standard opcodes here. We know the lengths
        // of such opcodes because they are specified in the prologue
        // as a multiple of LEB128 operands for each opcode.
        {
          assert(Opcode - 1U < Prologue.StandardOpcodeLengths.size());
          uint8_t OpcodeLength = Prologue.StandardOpcodeLengths[Opcode - 1];
          for (uint8_t I = 0; I < OpcodeLength; ++I) {
            uint64_t Value = DebugLineData.getULEB128(OffsetPtr);
            if (OS)
              *OS << format("Skipping ULEB128 value: 0x%16.16" PRIx64 ")\n",
                            Value);
          }
        }
        break;
      }
    } else {
      // Special Opcodes

      // A special opcode value is chosen based on the amount that needs
      // to be added to the line and address registers. The maximum line
      // increment for a special opcode is the value of the line_base
      // field in the header, plus the value of the line_range field,
      // minus 1 (line base + line range - 1). If the desired line
      // increment is greater than the maximum line increment, a standard
      // opcode must be used instead of a special opcode. The "address
      // advance" is calculated by dividing the desired address increment
      // by the minimum_instruction_length field from the header. The
      // special opcode is then calculated using the following formula:
      //
      //  opcode = (desired line increment - line_base) +
      //           (line_range * address advance) + opcode_base
      //
      // If the resulting opcode is greater than 255, a standard opcode
      // must be used instead.
      //
      // To decode a special opcode, subtract the opcode_base from the
      // opcode itself to give the adjusted opcode. The amount to
      // increment the address register is the result of the adjusted
      // opcode divided by the line_range multiplied by the
      // minimum_instruction_length field from the header. That is:
      //
      //  address increment = (adjusted opcode / line_range) *
      //                      minimum_instruction_length
      //
      // The amount to increment the line register is the line_base plus
      // the result of the adjusted opcode modulo the line_range. That is:
      //
      // line increment = line_base + (adjusted opcode % line_range)

      uint8_t AdjustOpcode = Opcode - Prologue.OpcodeBase;
      uint64_t AddrOffset =
          (AdjustOpcode / Prologue.LineRange) * Prologue.MinInstLength;
      int32_t LineOffset =
          Prologue.LineBase + (AdjustOpcode % Prologue.LineRange);
      State.Row.Line += LineOffset;
      State.Row.Address.Address += AddrOffset;

      if (OS) {
        *OS << "address += " << AddrOffset << ",  line += " << LineOffset
            << "\n";
        OS->indent(12);
        State.Row.dump(*OS);
      }

      State.appendRowToMatrix();
    }
    if(OS)
      *OS << "\n";
  }

  if (!State.Sequence.Empty)
    RecoverableErrorCallback(
        createStringError(errc::illegal_byte_sequence,
                    "last sequence in debug line table is not terminated!"));

  // Sort all sequences so that address lookup will work faster.
  if (!Sequences.empty()) {
    llvm::sort(Sequences, Sequence::orderByHighPC);
    // Note: actually, instruction address ranges of sequences should not
    // overlap (in shared objects and executables). If they do, the address
    // lookup would still work, though, but result would be ambiguous.
    // We don't report warning in this case. For example,
    // sometimes .so compiled from multiple object files contains a few
    // rudimentary sequences for address ranges [0x0, 0xsomething).
  }

  return Error::success();
}

uint32_t DWARFDebugLine::LineTable::findRowInSeq(
    const DWARFDebugLine::Sequence &Seq,
    object::SectionedAddress Address) const {
  if (!Seq.containsPC(Address))
    return UnknownRowIndex;
  assert(Seq.SectionIndex == Address.SectionIndex);
  // In some cases, e.g. first instruction in a function, the compiler generates
  // two entries, both with the same address. We want the last one.
  //
  // In general we want a non-empty range: the last row whose address is less
  // than or equal to Address. This can be computed as upper_bound - 1.
  DWARFDebugLine::Row Row;
  Row.Address = Address;
  RowIter FirstRow = Rows.begin() + Seq.FirstRowIndex;
  RowIter LastRow = Rows.begin() + Seq.LastRowIndex;
  assert(FirstRow->Address.Address <= Row.Address.Address &&
         Row.Address.Address < LastRow[-1].Address.Address);
  RowIter RowPos = std::upper_bound(FirstRow + 1, LastRow - 1, Row,
                                    DWARFDebugLine::Row::orderByAddress) -
                   1;
  assert(Seq.SectionIndex == RowPos->Address.SectionIndex);
  return RowPos - Rows.begin();
}

uint32_t DWARFDebugLine::LineTable::lookupAddress(
    object::SectionedAddress Address) const {

  // Search for relocatable addresses
  uint32_t Result = lookupAddressImpl(Address);

  if (Result != UnknownRowIndex ||
      Address.SectionIndex == object::SectionedAddress::UndefSection)
    return Result;

  // Search for absolute addresses
  Address.SectionIndex = object::SectionedAddress::UndefSection;
  return lookupAddressImpl(Address);
}

uint32_t DWARFDebugLine::LineTable::lookupAddressImpl(
    object::SectionedAddress Address) const {
  // First, find an instruction sequence containing the given address.
  DWARFDebugLine::Sequence Sequence;
  Sequence.SectionIndex = Address.SectionIndex;
  Sequence.HighPC = Address.Address;
  SequenceIter It = llvm::upper_bound(Sequences, Sequence,
                                      DWARFDebugLine::Sequence::orderByHighPC);
  if (It == Sequences.end() || It->SectionIndex != Address.SectionIndex)
    return UnknownRowIndex;
  return findRowInSeq(*It, Address);
}

bool DWARFDebugLine::LineTable::lookupAddressRange(
    object::SectionedAddress Address, uint64_t Size,
    std::vector<uint32_t> &Result) const {

  // Search for relocatable addresses
  if (lookupAddressRangeImpl(Address, Size, Result))
    return true;

  if (Address.SectionIndex == object::SectionedAddress::UndefSection)
    return false;

  // Search for absolute addresses
  Address.SectionIndex = object::SectionedAddress::UndefSection;
  return lookupAddressRangeImpl(Address, Size, Result);
}

bool DWARFDebugLine::LineTable::lookupAddressRangeImpl(
    object::SectionedAddress Address, uint64_t Size,
    std::vector<uint32_t> &Result) const {
  if (Sequences.empty())
    return false;
  uint64_t EndAddr = Address.Address + Size;
  // First, find an instruction sequence containing the given address.
  DWARFDebugLine::Sequence Sequence;
  Sequence.SectionIndex = Address.SectionIndex;
  Sequence.HighPC = Address.Address;
  SequenceIter LastSeq = Sequences.end();
  SequenceIter SeqPos = llvm::upper_bound(
      Sequences, Sequence, DWARFDebugLine::Sequence::orderByHighPC);
  if (SeqPos == LastSeq || !SeqPos->containsPC(Address))
    return false;

  SequenceIter StartPos = SeqPos;

  // Add the rows from the first sequence to the vector, starting with the
  // index we just calculated

  while (SeqPos != LastSeq && SeqPos->LowPC < EndAddr) {
    const DWARFDebugLine::Sequence &CurSeq = *SeqPos;
    // For the first sequence, we need to find which row in the sequence is the
    // first in our range.
    uint32_t FirstRowIndex = CurSeq.FirstRowIndex;
    if (SeqPos == StartPos)
      FirstRowIndex = findRowInSeq(CurSeq, Address);

    // Figure out the last row in the range.
    uint32_t LastRowIndex =
        findRowInSeq(CurSeq, {EndAddr - 1, Address.SectionIndex});
    if (LastRowIndex == UnknownRowIndex)
      LastRowIndex = CurSeq.LastRowIndex - 1;

    assert(FirstRowIndex != UnknownRowIndex);
    assert(LastRowIndex != UnknownRowIndex);

    for (uint32_t I = FirstRowIndex; I <= LastRowIndex; ++I) {
      Result.push_back(I);
    }

    ++SeqPos;
  }

  return true;
}

Optional<StringRef> DWARFDebugLine::LineTable::getSourceByIndex(uint64_t FileIndex,
                                                                FileLineInfoKind Kind) const {
  if (Kind == FileLineInfoKind::None || !Prologue.hasFileAtIndex(FileIndex))
    return None;
  const FileNameEntry &Entry = Prologue.getFileNameEntry(FileIndex);
  if (Optional<const char *> source = Entry.Source.getAsCString())
    return StringRef(*source);
  return None;
}

static bool isPathAbsoluteOnWindowsOrPosix(const Twine &Path) {
  // Debug info can contain paths from any OS, not necessarily
  // an OS we're currently running on. Moreover different compilation units can
  // be compiled on different operating systems and linked together later.
  return sys::path::is_absolute(Path, sys::path::Style::posix) ||
         sys::path::is_absolute(Path, sys::path::Style::windows);
}

bool DWARFDebugLine::Prologue::getFileNameByIndex(uint64_t FileIndex,
                                                  StringRef CompDir,
                                                  FileLineInfoKind Kind,
                                                  std::string &Result) const {
  if (Kind == FileLineInfoKind::None || !hasFileAtIndex(FileIndex))
    return false;
  const FileNameEntry &Entry = getFileNameEntry(FileIndex);
  StringRef FileName = Entry.Name.getAsCString().getValue();
  if (Kind != FileLineInfoKind::AbsoluteFilePath ||
      isPathAbsoluteOnWindowsOrPosix(FileName)) {
    Result = FileName;
    return true;
  }

  SmallString<16> FilePath;
  StringRef IncludeDir;
  // Be defensive about the contents of Entry.
  if (getVersion() >= 5) {
    if (Entry.DirIdx < IncludeDirectories.size())
      IncludeDir = IncludeDirectories[Entry.DirIdx].getAsCString().getValue();
  } else {
    if (0 < Entry.DirIdx && Entry.DirIdx <= IncludeDirectories.size())
      IncludeDir =
          IncludeDirectories[Entry.DirIdx - 1].getAsCString().getValue();

    // We may still need to append compilation directory of compile unit.
    // We know that FileName is not absolute, the only way to have an
    // absolute path at this point would be if IncludeDir is absolute.
    if (!CompDir.empty() && !isPathAbsoluteOnWindowsOrPosix(IncludeDir))
      sys::path::append(FilePath, CompDir);
  }

  // sys::path::append skips empty strings.
  sys::path::append(FilePath, IncludeDir, FileName);
  Result = FilePath.str();
  return true;
}

bool DWARFDebugLine::LineTable::getFileLineInfoForAddress(
    object::SectionedAddress Address, const char *CompDir,
    FileLineInfoKind Kind, DILineInfo &Result) const {
  // Get the index of row we're looking for in the line table.
  uint32_t RowIndex = lookupAddress(Address);
  if (RowIndex == -1U)
    return false;
  // Take file number and line/column from the row.
  const auto &Row = Rows[RowIndex];
  if (!getFileNameByIndex(Row.File, CompDir, Kind, Result.FileName))
    return false;
  Result.Line = Row.Line;
  Result.Column = Row.Column;
  Result.Discriminator = Row.Discriminator;
  Result.Source = getSourceByIndex(Row.File, Kind);
  return true;
}

// We want to supply the Unit associated with a .debug_line[.dwo] table when
// we dump it, if possible, but still dump the table even if there isn't a Unit.
// Therefore, collect up handles on all the Units that point into the
// line-table section.
static DWARFDebugLine::SectionParser::LineToUnitMap
buildLineToUnitMap(DWARFDebugLine::SectionParser::cu_range CUs,
                   DWARFDebugLine::SectionParser::tu_range TUs) {
  DWARFDebugLine::SectionParser::LineToUnitMap LineToUnit;
  for (const auto &CU : CUs)
    if (auto CUDIE = CU->getUnitDIE())
      if (auto StmtOffset = toSectionOffset(CUDIE.find(DW_AT_stmt_list)))
        LineToUnit.insert(std::make_pair(*StmtOffset, &*CU));
  for (const auto &TU : TUs)
    if (auto TUDIE = TU->getUnitDIE())
      if (auto StmtOffset = toSectionOffset(TUDIE.find(DW_AT_stmt_list)))
        LineToUnit.insert(std::make_pair(*StmtOffset, &*TU));
  return LineToUnit;
}

DWARFDebugLine::SectionParser::SectionParser(DWARFDataExtractor &Data,
                                             const DWARFContext &C,
                                             cu_range CUs, tu_range TUs)
    : DebugLineData(Data), Context(C) {
  LineToUnit = buildLineToUnitMap(CUs, TUs);
  if (!DebugLineData.isValidOffset(Offset))
    Done = true;
}

bool DWARFDebugLine::Prologue::totalLengthIsValid() const {
  return TotalLength == 0xffffffff || TotalLength < 0xfffffff0;
}

DWARFDebugLine::LineTable DWARFDebugLine::SectionParser::parseNext(
    function_ref<void(Error)> RecoverableErrorCallback,
    function_ref<void(Error)> UnrecoverableErrorCallback, raw_ostream *OS) {
  assert(DebugLineData.isValidOffset(Offset) &&
         "parsing should have terminated");
  DWARFUnit *U = prepareToParse(Offset);
  uint32_t OldOffset = Offset;
  LineTable LT;
  if (Error Err = LT.parse(DebugLineData, &Offset, Context, U,
                           RecoverableErrorCallback, OS))
    UnrecoverableErrorCallback(std::move(Err));
  moveToNextTable(OldOffset, LT.Prologue);
  return LT;
}

void DWARFDebugLine::SectionParser::skip(
    function_ref<void(Error)> ErrorCallback) {
  assert(DebugLineData.isValidOffset(Offset) &&
         "parsing should have terminated");
  DWARFUnit *U = prepareToParse(Offset);
  uint32_t OldOffset = Offset;
  LineTable LT;
  if (Error Err = LT.Prologue.parse(DebugLineData, &Offset, Context, U))
    ErrorCallback(std::move(Err));
  moveToNextTable(OldOffset, LT.Prologue);
}

DWARFUnit *DWARFDebugLine::SectionParser::prepareToParse(uint32_t Offset) {
  DWARFUnit *U = nullptr;
  auto It = LineToUnit.find(Offset);
  if (It != LineToUnit.end())
    U = It->second;
  DebugLineData.setAddressSize(U ? U->getAddressByteSize() : 0);
  return U;
}

void DWARFDebugLine::SectionParser::moveToNextTable(uint32_t OldOffset,
                                                    const Prologue &P) {
  // If the length field is not valid, we don't know where the next table is, so
  // cannot continue to parse. Mark the parser as done, and leave the Offset
  // value as it currently is. This will be the end of the bad length field.
  if (!P.totalLengthIsValid()) {
    Done = true;
    return;
  }

  Offset = OldOffset + P.TotalLength + P.sizeofTotalLength();
  if (!DebugLineData.isValidOffset(Offset)) {
    Done = true;
  }
}