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
 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
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
/* Support routines for building symbol tables in GDB's internal format.
   Copyright (C) 1986-2020 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "buildsym-legacy.h"
#include "bfd.h"
#include "gdb_obstack.h"
#include "symtab.h"
#include "symfile.h"
#include "objfiles.h"
#include "gdbtypes.h"
#include "complaints.h"
#include "expression.h"		/* For "enum exp_opcode" used by...  */
#include "filenames.h"		/* For DOSish file names.  */
#include "macrotab.h"
#include "demangle.h"		/* Needed by SYMBOL_INIT_DEMANGLED_NAME.  */
#include "block.h"
#include "cp-support.h"
#include "dictionary.h"
#include "addrmap.h"
#include <algorithm>

/* For cleanup_undefined_stabs_types and finish_global_stabs (somewhat
   questionable--see comment where we call them).  */

#include "stabsread.h"

/* List of blocks already made (lexical contexts already closed).
   This is used at the end to make the blockvector.  */

struct pending_block
  {
    struct pending_block *next;
    struct block *block;
  };

/* Initial sizes of data structures.  These are realloc'd larger if
   needed, and realloc'd down to the size actually used, when
   completed.  */

#define	INITIAL_LINE_VECTOR_LENGTH	1000


buildsym_compunit::buildsym_compunit (struct objfile *objfile_,
				      const char *name,
				      const char *comp_dir_,
				      enum language language_,
				      CORE_ADDR last_addr)
  : m_objfile (objfile_),
    m_last_source_file (name == nullptr ? nullptr : xstrdup (name)),
    m_comp_dir (comp_dir_ == nullptr ? nullptr : xstrdup (comp_dir_)),
    m_language (language_),
    m_last_source_start_addr (last_addr)
{
  /* Allocate the compunit symtab now.  The caller needs it to allocate
     non-primary symtabs.  It is also needed by get_macro_table.  */
  m_compunit_symtab = allocate_compunit_symtab (m_objfile, name);

  /* Build the subfile for NAME (the main source file) so that we can record
     a pointer to it for later.
     IMPORTANT: Do not allocate a struct symtab for NAME here.
     It can happen that the debug info provides a different path to NAME than
     DIRNAME,NAME.  We cope with this in watch_main_source_file_lossage but
     that only works if the main_subfile doesn't have a symtab yet.  */
  start_subfile (name);
  /* Save this so that we don't have to go looking for it at the end
     of the subfiles list.  */
  m_main_subfile = m_current_subfile;
}

buildsym_compunit::~buildsym_compunit ()
{
  struct subfile *subfile, *nextsub;

  if (m_pending_macros != nullptr)
    free_macro_table (m_pending_macros);

  for (subfile = m_subfiles;
       subfile != NULL;
       subfile = nextsub)
    {
      nextsub = subfile->next;
      xfree (subfile->name);
      xfree (subfile->line_vector);
      xfree (subfile);
    }

  struct pending *next, *next1;

  for (next = m_file_symbols; next != NULL; next = next1)
    {
      next1 = next->next;
      xfree ((void *) next);
    }

  for (next = m_global_symbols; next != NULL; next = next1)
    {
      next1 = next->next;
      xfree ((void *) next);
    }
}

struct macro_table *
buildsym_compunit::get_macro_table ()
{
  if (m_pending_macros == nullptr)
    m_pending_macros = new_macro_table (&m_objfile->per_bfd->storage_obstack,
					&m_objfile->per_bfd->string_cache,
					m_compunit_symtab);
  return m_pending_macros;
}

/* Maintain the lists of symbols and blocks.  */

/* Add a symbol to one of the lists of symbols.  */

void
add_symbol_to_list (struct symbol *symbol, struct pending **listhead)
{
  struct pending *link;

  /* If this is an alias for another symbol, don't add it.  */
  if (symbol->linkage_name () && symbol->linkage_name ()[0] == '#')
    return;

  /* We keep PENDINGSIZE symbols in each link of the list.  If we
     don't have a link with room in it, add a new link.  */
  if (*listhead == NULL || (*listhead)->nsyms == PENDINGSIZE)
    {
      link = XNEW (struct pending);
      link->next = *listhead;
      *listhead = link;
      link->nsyms = 0;
    }

  (*listhead)->symbol[(*listhead)->nsyms++] = symbol;
}

/* Find a symbol named NAME on a LIST.  NAME need not be
   '\0'-terminated; LENGTH is the length of the name.  */

struct symbol *
find_symbol_in_list (struct pending *list, char *name, int length)
{
  int j;
  const char *pp;

  while (list != NULL)
    {
      for (j = list->nsyms; --j >= 0;)
	{
	  pp = list->symbol[j]->linkage_name ();
	  if (*pp == *name && strncmp (pp, name, length) == 0
	      && pp[length] == '\0')
	    {
	      return (list->symbol[j]);
	    }
	}
      list = list->next;
    }
  return (NULL);
}

/* Record BLOCK on the list of all blocks in the file.  Put it after
   OPBLOCK, or at the beginning if opblock is NULL.  This puts the
   block in the list after all its subblocks.  */

void
buildsym_compunit::record_pending_block (struct block *block,
					 struct pending_block *opblock)
{
  struct pending_block *pblock;

  pblock = XOBNEW (&m_pending_block_obstack, struct pending_block);
  pblock->block = block;
  if (opblock)
    {
      pblock->next = opblock->next;
      opblock->next = pblock;
    }
  else
    {
      pblock->next = m_pending_blocks;
      m_pending_blocks = pblock;
    }
}

/* Take one of the lists of symbols and make a block from it.  Keep
   the order the symbols have in the list (reversed from the input
   file).  Put the block on the list of pending blocks.  */

struct block *
buildsym_compunit::finish_block_internal
    (struct symbol *symbol,
     struct pending **listhead,
     struct pending_block *old_blocks,
     const struct dynamic_prop *static_link,
     CORE_ADDR start, CORE_ADDR end,
     int is_global, int expandable)
{
  struct gdbarch *gdbarch = m_objfile->arch ();
  struct pending *next, *next1;
  struct block *block;
  struct pending_block *pblock;
  struct pending_block *opblock;

  block = (is_global
	   ? allocate_global_block (&m_objfile->objfile_obstack)
	   : allocate_block (&m_objfile->objfile_obstack));

  if (symbol)
    {
      BLOCK_MULTIDICT (block)
	= mdict_create_linear (&m_objfile->objfile_obstack, *listhead);
    }
  else
    {
      if (expandable)
	{
	  BLOCK_MULTIDICT (block) = mdict_create_hashed_expandable (m_language);
	  mdict_add_pending (BLOCK_MULTIDICT (block), *listhead);
	}
      else
	{
	  BLOCK_MULTIDICT (block) =
	    mdict_create_hashed (&m_objfile->objfile_obstack, *listhead);
	}
    }

  BLOCK_START (block) = start;
  BLOCK_END (block) = end;

  /* Put the block in as the value of the symbol that names it.  */

  if (symbol)
    {
      struct type *ftype = SYMBOL_TYPE (symbol);
      struct mdict_iterator miter;
      SYMBOL_BLOCK_VALUE (symbol) = block;
      BLOCK_FUNCTION (block) = symbol;

      if (ftype->num_fields () <= 0)
	{
	  /* No parameter type information is recorded with the
	     function's type.  Set that from the type of the
	     parameter symbols.  */
	  int nparams = 0, iparams;
	  struct symbol *sym;

	  /* Here we want to directly access the dictionary, because
	     we haven't fully initialized the block yet.  */
	  ALL_DICT_SYMBOLS (BLOCK_MULTIDICT (block), miter, sym)
	    {
	      if (SYMBOL_IS_ARGUMENT (sym))
		nparams++;
	    }
	  if (nparams > 0)
	    {
	      ftype->set_num_fields (nparams);
	      ftype->set_fields
		((struct field *)
		 TYPE_ALLOC (ftype, nparams * sizeof (struct field)));

	      iparams = 0;
	      /* Here we want to directly access the dictionary, because
		 we haven't fully initialized the block yet.  */
	      ALL_DICT_SYMBOLS (BLOCK_MULTIDICT (block), miter, sym)
		{
		  if (iparams == nparams)
		    break;

		  if (SYMBOL_IS_ARGUMENT (sym))
		    {
		      ftype->field (iparams).set_type (SYMBOL_TYPE (sym));
		      TYPE_FIELD_ARTIFICIAL (ftype, iparams) = 0;
		      iparams++;
		    }
		}
	    }
	}
    }
  else
    {
      BLOCK_FUNCTION (block) = NULL;
    }

  if (static_link != NULL)
    objfile_register_static_link (m_objfile, block, static_link);

  /* Now free the links of the list, and empty the list.  */

  for (next = *listhead; next; next = next1)
    {
      next1 = next->next;
      xfree (next);
    }
  *listhead = NULL;

  /* Check to be sure that the blocks have an end address that is
     greater than starting address.  */

  if (BLOCK_END (block) < BLOCK_START (block))
    {
      if (symbol)
	{
	  complaint (_("block end address less than block "
		       "start address in %s (patched it)"),
		     symbol->print_name ());
	}
      else
	{
	  complaint (_("block end address %s less than block "
		       "start address %s (patched it)"),
		     paddress (gdbarch, BLOCK_END (block)),
		     paddress (gdbarch, BLOCK_START (block)));
	}
      /* Better than nothing.  */
      BLOCK_END (block) = BLOCK_START (block);
    }

  /* Install this block as the superblock of all blocks made since the
     start of this scope that don't have superblocks yet.  */

  opblock = NULL;
  for (pblock = m_pending_blocks;
       pblock && pblock != old_blocks; 
       pblock = pblock->next)
    {
      if (BLOCK_SUPERBLOCK (pblock->block) == NULL)
	{
	  /* Check to be sure the blocks are nested as we receive
	     them.  If the compiler/assembler/linker work, this just
	     burns a small amount of time.

	     Skip blocks which correspond to a function; they're not
	     physically nested inside this other blocks, only
	     lexically nested.  */
	  if (BLOCK_FUNCTION (pblock->block) == NULL
	      && (BLOCK_START (pblock->block) < BLOCK_START (block)
		  || BLOCK_END (pblock->block) > BLOCK_END (block)))
	    {
	      if (symbol)
		{
		  complaint (_("inner block not inside outer block in %s"),
			     symbol->print_name ());
		}
	      else
		{
		  complaint (_("inner block (%s-%s) not "
			       "inside outer block (%s-%s)"),
			     paddress (gdbarch, BLOCK_START (pblock->block)),
			     paddress (gdbarch, BLOCK_END (pblock->block)),
			     paddress (gdbarch, BLOCK_START (block)),
			     paddress (gdbarch, BLOCK_END (block)));
		}
	      if (BLOCK_START (pblock->block) < BLOCK_START (block))
		BLOCK_START (pblock->block) = BLOCK_START (block);
	      if (BLOCK_END (pblock->block) > BLOCK_END (block))
		BLOCK_END (pblock->block) = BLOCK_END (block);
	    }
	  BLOCK_SUPERBLOCK (pblock->block) = block;
	}
      opblock = pblock;
    }

  block_set_using (block,
		   (is_global
		    ? m_global_using_directives
		    : m_local_using_directives),
		   &m_objfile->objfile_obstack);
  if (is_global)
    m_global_using_directives = NULL;
  else
    m_local_using_directives = NULL;

  record_pending_block (block, opblock);

  return block;
}

struct block *
buildsym_compunit::finish_block (struct symbol *symbol,
				 struct pending_block *old_blocks,
				 const struct dynamic_prop *static_link,
				 CORE_ADDR start, CORE_ADDR end)
{
  return finish_block_internal (symbol, &m_local_symbols,
				old_blocks, static_link, start, end, 0, 0);
}

/* Record that the range of addresses from START to END_INCLUSIVE
   (inclusive, like it says) belongs to BLOCK.  BLOCK's start and end
   addresses must be set already.  You must apply this function to all
   BLOCK's children before applying it to BLOCK.

   If a call to this function complicates the picture beyond that
   already provided by BLOCK_START and BLOCK_END, then we create an
   address map for the block.  */
void
buildsym_compunit::record_block_range (struct block *block,
				       CORE_ADDR start,
				       CORE_ADDR end_inclusive)
{
  /* If this is any different from the range recorded in the block's
     own BLOCK_START and BLOCK_END, then note that the address map has
     become interesting.  Note that even if this block doesn't have
     any "interesting" ranges, some later block might, so we still
     need to record this block in the addrmap.  */
  if (start != BLOCK_START (block)
      || end_inclusive + 1 != BLOCK_END (block))
    m_pending_addrmap_interesting = true;

  if (m_pending_addrmap == nullptr)
    m_pending_addrmap = addrmap_create_mutable (&m_pending_addrmap_obstack);

  addrmap_set_empty (m_pending_addrmap, start, end_inclusive, block);
}

struct blockvector *
buildsym_compunit::make_blockvector ()
{
  struct pending_block *next;
  struct blockvector *blockvector;
  int i;

  /* Count the length of the list of blocks.  */

  for (next = m_pending_blocks, i = 0; next; next = next->next, i++)
    {
    }

  blockvector = (struct blockvector *)
    obstack_alloc (&m_objfile->objfile_obstack,
		   (sizeof (struct blockvector)
		    + (i - 1) * sizeof (struct block *)));

  /* Copy the blocks into the blockvector.  This is done in reverse
     order, which happens to put the blocks into the proper order
     (ascending starting address).  finish_block has hair to insert
     each block into the list after its subblocks in order to make
     sure this is true.  */

  BLOCKVECTOR_NBLOCKS (blockvector) = i;
  for (next = m_pending_blocks; next; next = next->next)
    {
      BLOCKVECTOR_BLOCK (blockvector, --i) = next->block;
    }

  free_pending_blocks ();

  /* If we needed an address map for this symtab, record it in the
     blockvector.  */
  if (m_pending_addrmap != nullptr && m_pending_addrmap_interesting)
    BLOCKVECTOR_MAP (blockvector)
      = addrmap_create_fixed (m_pending_addrmap, &m_objfile->objfile_obstack);
  else
    BLOCKVECTOR_MAP (blockvector) = 0;

  /* Some compilers output blocks in the wrong order, but we depend on
     their being in the right order so we can binary search.  Check the
     order and moan about it.
     Note: Remember that the first two blocks are the global and static
     blocks.  We could special case that fact and begin checking at block 2.
     To avoid making that assumption we do not.  */
  if (BLOCKVECTOR_NBLOCKS (blockvector) > 1)
    {
      for (i = 1; i < BLOCKVECTOR_NBLOCKS (blockvector); i++)
	{
	  if (BLOCK_START (BLOCKVECTOR_BLOCK (blockvector, i - 1))
	      > BLOCK_START (BLOCKVECTOR_BLOCK (blockvector, i)))
	    {
	      CORE_ADDR start
		= BLOCK_START (BLOCKVECTOR_BLOCK (blockvector, i));

	      complaint (_("block at %s out of order"),
			 hex_string ((LONGEST) start));
	    }
	}
    }

  return (blockvector);
}

/* Start recording information about source code that came from an
   included (or otherwise merged-in) source file with a different
   name.  NAME is the name of the file (cannot be NULL).  */

void
buildsym_compunit::start_subfile (const char *name)
{
  const char *subfile_dirname;
  struct subfile *subfile;

  subfile_dirname = m_comp_dir.get ();

  /* See if this subfile is already registered.  */

  for (subfile = m_subfiles; subfile; subfile = subfile->next)
    {
      char *subfile_name;

      /* If NAME is an absolute path, and this subfile is not, then
	 attempt to create an absolute path to compare.  */
      if (IS_ABSOLUTE_PATH (name)
	  && !IS_ABSOLUTE_PATH (subfile->name)
	  && subfile_dirname != NULL)
	subfile_name = concat (subfile_dirname, SLASH_STRING,
			       subfile->name, (char *) NULL);
      else
	subfile_name = subfile->name;

      if (FILENAME_CMP (subfile_name, name) == 0)
	{
	  m_current_subfile = subfile;
	  if (subfile_name != subfile->name)
	    xfree (subfile_name);
	  return;
	}
      if (subfile_name != subfile->name)
	xfree (subfile_name);
    }

  /* This subfile is not known.  Add an entry for it.  */

  subfile = XNEW (struct subfile);
  memset (subfile, 0, sizeof (struct subfile));
  subfile->buildsym_compunit = this;

  subfile->next = m_subfiles;
  m_subfiles = subfile;

  m_current_subfile = subfile;

  subfile->name = xstrdup (name);

  /* Initialize line-number recording for this subfile.  */
  subfile->line_vector = NULL;

  /* Default the source language to whatever can be deduced from the
     filename.  If nothing can be deduced (such as for a C/C++ include
     file with a ".h" extension), then inherit whatever language the
     previous subfile had.  This kludgery is necessary because there
     is no standard way in some object formats to record the source
     language.  Also, when symtabs are allocated we try to deduce a
     language then as well, but it is too late for us to use that
     information while reading symbols, since symtabs aren't allocated
     until after all the symbols have been processed for a given
     source file.  */

  subfile->language = deduce_language_from_filename (subfile->name);
  if (subfile->language == language_unknown
      && subfile->next != NULL)
    {
      subfile->language = subfile->next->language;
    }

  /* If the filename of this subfile ends in .C, then change the
     language of any pending subfiles from C to C++.  We also accept
     any other C++ suffixes accepted by deduce_language_from_filename.  */
  /* Likewise for f2c.  */

  if (subfile->name)
    {
      struct subfile *s;
      enum language sublang = deduce_language_from_filename (subfile->name);

      if (sublang == language_cplus || sublang == language_fortran)
	for (s = m_subfiles; s != NULL; s = s->next)
	  if (s->language == language_c)
	    s->language = sublang;
    }

  /* And patch up this file if necessary.  */
  if (subfile->language == language_c
      && subfile->next != NULL
      && (subfile->next->language == language_cplus
	  || subfile->next->language == language_fortran))
    {
      subfile->language = subfile->next->language;
    }
}

/* For stabs readers, the first N_SO symbol is assumed to be the
   source file name, and the subfile struct is initialized using that
   assumption.  If another N_SO symbol is later seen, immediately
   following the first one, then the first one is assumed to be the
   directory name and the second one is really the source file name.

   So we have to patch up the subfile struct by moving the old name
   value to dirname and remembering the new name.  Some sanity
   checking is performed to ensure that the state of the subfile
   struct is reasonable and that the old name we are assuming to be a
   directory name actually is (by checking for a trailing '/').  */

void
buildsym_compunit::patch_subfile_names (struct subfile *subfile,
					const char *name)
{
  if (subfile != NULL
      && m_comp_dir == NULL
      && subfile->name != NULL
      && IS_DIR_SEPARATOR (subfile->name[strlen (subfile->name) - 1]))
    {
      m_comp_dir.reset (subfile->name);
      subfile->name = xstrdup (name);
      set_last_source_file (name);

      /* Default the source language to whatever can be deduced from
         the filename.  If nothing can be deduced (such as for a C/C++
         include file with a ".h" extension), then inherit whatever
         language the previous subfile had.  This kludgery is
         necessary because there is no standard way in some object
         formats to record the source language.  Also, when symtabs
         are allocated we try to deduce a language then as well, but
         it is too late for us to use that information while reading
         symbols, since symtabs aren't allocated until after all the
         symbols have been processed for a given source file.  */

      subfile->language = deduce_language_from_filename (subfile->name);
      if (subfile->language == language_unknown
	  && subfile->next != NULL)
	{
	  subfile->language = subfile->next->language;
	}
    }
}

/* Handle the N_BINCL and N_EINCL symbol types that act like N_SOL for
   switching source files (different subfiles, as we call them) within
   one object file, but using a stack rather than in an arbitrary
   order.  */

void
buildsym_compunit::push_subfile ()
{
  gdb_assert (m_current_subfile != NULL);
  gdb_assert (m_current_subfile->name != NULL);
  m_subfile_stack.push_back (m_current_subfile->name);
}

const char *
buildsym_compunit::pop_subfile ()
{
  gdb_assert (!m_subfile_stack.empty ());
  const char *name = m_subfile_stack.back ();
  m_subfile_stack.pop_back ();
  return name;
}

/* Add a linetable entry for line number LINE and address PC to the
   line vector for SUBFILE.  */

void
buildsym_compunit::record_line (struct subfile *subfile, int line,
				CORE_ADDR pc, bool is_stmt)
{
  struct linetable_entry *e;

  /* Make sure line vector exists and is big enough.  */
  if (!subfile->line_vector)
    {
      subfile->line_vector_length = INITIAL_LINE_VECTOR_LENGTH;
      subfile->line_vector = (struct linetable *)
	xmalloc (sizeof (struct linetable)
	   + subfile->line_vector_length * sizeof (struct linetable_entry));
      subfile->line_vector->nitems = 0;
      m_have_line_numbers = true;
    }

  if (subfile->line_vector->nitems >= subfile->line_vector_length)
    {
      subfile->line_vector_length *= 2;
      subfile->line_vector = (struct linetable *)
	xrealloc ((char *) subfile->line_vector,
		  (sizeof (struct linetable)
		   + (subfile->line_vector_length
		      * sizeof (struct linetable_entry))));
    }

  /* Normally, we treat lines as unsorted.  But the end of sequence
     marker is special.  We sort line markers at the same PC by line
     number, so end of sequence markers (which have line == 0) appear
     first.  This is right if the marker ends the previous function,
     and there is no padding before the next function.  But it is
     wrong if the previous line was empty and we are now marking a
     switch to a different subfile.  We must leave the end of sequence
     marker at the end of this group of lines, not sort the empty line
     to after the marker.  The easiest way to accomplish this is to
     delete any empty lines from our table, if they are followed by
     end of sequence markers.  All we lose is the ability to set
     breakpoints at some lines which contain no instructions
     anyway.  */
  if (line == 0)
    {
      while (subfile->line_vector->nitems > 0)
	{
	  e = subfile->line_vector->item + subfile->line_vector->nitems - 1;
	  if (e->pc != pc)
	    break;
	  subfile->line_vector->nitems--;
	}
    }

  e = subfile->line_vector->item + subfile->line_vector->nitems++;
  e->line = line;
  e->is_stmt = is_stmt ? 1 : 0;
  e->pc = pc;
}


/* Subroutine of end_symtab to simplify it.  Look for a subfile that
   matches the main source file's basename.  If there is only one, and
   if the main source file doesn't have any symbol or line number
   information, then copy this file's symtab and line_vector to the
   main source file's subfile and discard the other subfile.  This can
   happen because of a compiler bug or from the user playing games
   with #line or from things like a distributed build system that
   manipulates the debug info.  This can also happen from an innocent
   symlink in the paths, we don't canonicalize paths here.  */

void
buildsym_compunit::watch_main_source_file_lossage ()
{
  struct subfile *mainsub, *subfile;

  /* Get the main source file.  */
  mainsub = m_main_subfile;

  /* If the main source file doesn't have any line number or symbol
     info, look for an alias in another subfile.  */

  if (mainsub->line_vector == NULL
      && mainsub->symtab == NULL)
    {
      const char *mainbase = lbasename (mainsub->name);
      int nr_matches = 0;
      struct subfile *prevsub;
      struct subfile *mainsub_alias = NULL;
      struct subfile *prev_mainsub_alias = NULL;

      prevsub = NULL;
      for (subfile = m_subfiles;
	   subfile != NULL;
	   subfile = subfile->next)
	{
	  if (subfile == mainsub)
	    continue;
	  if (filename_cmp (lbasename (subfile->name), mainbase) == 0)
	    {
	      ++nr_matches;
	      mainsub_alias = subfile;
	      prev_mainsub_alias = prevsub;
	    }
	  prevsub = subfile;
	}

      if (nr_matches == 1)
	{
	  gdb_assert (mainsub_alias != NULL && mainsub_alias != mainsub);

	  /* Found a match for the main source file.
	     Copy its line_vector and symtab to the main subfile
	     and then discard it.  */

	  mainsub->line_vector = mainsub_alias->line_vector;
	  mainsub->line_vector_length = mainsub_alias->line_vector_length;
	  mainsub->symtab = mainsub_alias->symtab;

	  if (prev_mainsub_alias == NULL)
	    m_subfiles = mainsub_alias->next;
	  else
	    prev_mainsub_alias->next = mainsub_alias->next;
	  xfree (mainsub_alias->name);
	  xfree (mainsub_alias);
	}
    }
}

/* Implementation of the first part of end_symtab.  It allows modifying
   STATIC_BLOCK before it gets finalized by end_symtab_from_static_block.
   If the returned value is NULL there is no blockvector created for
   this symtab (you still must call end_symtab_from_static_block).

   END_ADDR is the same as for end_symtab: the address of the end of the
   file's text.

   If EXPANDABLE is non-zero the STATIC_BLOCK dictionary is made
   expandable.

   If REQUIRED is non-zero, then a symtab is created even if it does
   not contain any symbols.  */

struct block *
buildsym_compunit::end_symtab_get_static_block (CORE_ADDR end_addr,
						int expandable, int required)
{
  /* Finish the lexical context of the last function in the file; pop
     the context stack.  */

  if (!m_context_stack.empty ())
    {
      struct context_stack cstk = pop_context ();

      /* Make a block for the local symbols within.  */
      finish_block (cstk.name, cstk.old_blocks, NULL,
		    cstk.start_addr, end_addr);

      if (!m_context_stack.empty ())
	{
	  /* This is said to happen with SCO.  The old coffread.c
	     code simply emptied the context stack, so we do the
	     same.  FIXME: Find out why it is happening.  This is not
	     believed to happen in most cases (even for coffread.c);
	     it used to be an abort().  */
	  complaint (_("Context stack not empty in end_symtab"));
	  m_context_stack.clear ();
	}
    }

  /* Reordered executables may have out of order pending blocks; if
     OBJF_REORDERED is true, then sort the pending blocks.  */

  if ((m_objfile->flags & OBJF_REORDERED) && m_pending_blocks)
    {
      struct pending_block *pb;

      std::vector<block *> barray;

      for (pb = m_pending_blocks; pb != NULL; pb = pb->next)
	barray.push_back (pb->block);

      /* Sort blocks by start address in descending order.  Blocks with the
	 same start address must remain in the original order to preserve
	 inline function caller/callee relationships.  */
      std::stable_sort (barray.begin (), barray.end (),
			[] (const block *a, const block *b)
			{
			  return BLOCK_START (a) > BLOCK_START (b);
			});

      int i = 0;
      for (pb = m_pending_blocks; pb != NULL; pb = pb->next)
	pb->block = barray[i++];
    }

  /* Cleanup any undefined types that have been left hanging around
     (this needs to be done before the finish_blocks so that
     file_symbols is still good).

     Both cleanup_undefined_stabs_types and finish_global_stabs are stabs
     specific, but harmless for other symbol readers, since on gdb
     startup or when finished reading stabs, the state is set so these
     are no-ops.  FIXME: Is this handled right in case of QUIT?  Can
     we make this cleaner?  */

  cleanup_undefined_stabs_types (m_objfile);
  finish_global_stabs (m_objfile);

  if (!required
      && m_pending_blocks == NULL
      && m_file_symbols == NULL
      && m_global_symbols == NULL
      && !m_have_line_numbers
      && m_pending_macros == NULL
      && m_global_using_directives == NULL)
    {
      /* Ignore symtabs that have no functions with real debugging info.  */
      return NULL;
    }
  else
    {
      /* Define the STATIC_BLOCK.  */
      return finish_block_internal (NULL, get_file_symbols (), NULL, NULL,
				    m_last_source_start_addr,
				    end_addr, 0, expandable);
    }
}

/* Subroutine of end_symtab_from_static_block to simplify it.
   Handle the "have blockvector" case.
   See end_symtab_from_static_block for a description of the arguments.  */

struct compunit_symtab *
buildsym_compunit::end_symtab_with_blockvector (struct block *static_block,
						int section, int expandable)
{
  struct compunit_symtab *cu = m_compunit_symtab;
  struct blockvector *blockvector;
  struct subfile *subfile;
  CORE_ADDR end_addr;

  gdb_assert (static_block != NULL);
  gdb_assert (m_subfiles != NULL);

  end_addr = BLOCK_END (static_block);

  /* Create the GLOBAL_BLOCK and build the blockvector.  */
  finish_block_internal (NULL, get_global_symbols (), NULL, NULL,
			 m_last_source_start_addr, end_addr,
			 1, expandable);
  blockvector = make_blockvector ();

  /* Read the line table if it has to be read separately.
     This is only used by xcoffread.c.  */
  if (m_objfile->sf->sym_read_linetable != NULL)
    m_objfile->sf->sym_read_linetable (m_objfile);

  /* Handle the case where the debug info specifies a different path
     for the main source file.  It can cause us to lose track of its
     line number information.  */
  watch_main_source_file_lossage ();

  /* Now create the symtab objects proper, if not already done,
     one for each subfile.  */

  for (subfile = m_subfiles;
       subfile != NULL;
       subfile = subfile->next)
    {
      int linetablesize = 0;

      if (subfile->line_vector)
	{
	  linetablesize = sizeof (struct linetable) +
	    subfile->line_vector->nitems * sizeof (struct linetable_entry);

	  const auto lte_is_less_than
	    = [] (const linetable_entry &ln1,
		  const linetable_entry &ln2) -> bool
	      {
		if (ln1.pc == ln2.pc
		    && ((ln1.line == 0) != (ln2.line == 0)))
		  return ln1.line == 0;

		return (ln1.pc < ln2.pc);
	      };

	  /* Like the pending blocks, the line table may be scrambled in
	     reordered executables.  Sort it if OBJF_REORDERED is true.  It
	     is important to preserve the order of lines at the same
	     address, as this maintains the inline function caller/callee
	     relationships, this is why std::stable_sort is used.  */
	  if (m_objfile->flags & OBJF_REORDERED)
	    std::stable_sort (subfile->line_vector->item,
			      subfile->line_vector->item
			      + subfile->line_vector->nitems,
			      lte_is_less_than);
	}

      /* Allocate a symbol table if necessary.  */
      if (subfile->symtab == NULL)
	subfile->symtab = allocate_symtab (cu, subfile->name);
      struct symtab *symtab = subfile->symtab;

      /* Fill in its components.  */

      if (subfile->line_vector)
	{
	  /* Reallocate the line table on the symbol obstack.  */
	  SYMTAB_LINETABLE (symtab) = (struct linetable *)
	    obstack_alloc (&m_objfile->objfile_obstack, linetablesize);
	  memcpy (SYMTAB_LINETABLE (symtab), subfile->line_vector,
		  linetablesize);
	}
      else
	{
	  SYMTAB_LINETABLE (symtab) = NULL;
	}

      /* Use whatever language we have been using for this
	 subfile, not the one that was deduced in allocate_symtab
	 from the filename.  We already did our own deducing when
	 we created the subfile, and we may have altered our
	 opinion of what language it is from things we found in
	 the symbols.  */
      symtab->language = subfile->language;
    }

  /* Make sure the symtab of main_subfile is the first in its list.  */
  {
    struct symtab *main_symtab, *prev_symtab;

    main_symtab = m_main_subfile->symtab;
    prev_symtab = NULL;
    for (symtab *symtab : compunit_filetabs (cu))
      {
	if (symtab == main_symtab)
	  {
	    if (prev_symtab != NULL)
	      {
		prev_symtab->next = main_symtab->next;
		main_symtab->next = COMPUNIT_FILETABS (cu);
		COMPUNIT_FILETABS (cu) = main_symtab;
	      }
	    break;
	  }
	prev_symtab = symtab;
      }
    gdb_assert (main_symtab == COMPUNIT_FILETABS (cu));
  }

  /* Fill out the compunit symtab.  */

  if (m_comp_dir != NULL)
    {
      /* Reallocate the dirname on the symbol obstack.  */
      const char *comp_dir = m_comp_dir.get ();
      COMPUNIT_DIRNAME (cu) = obstack_strdup (&m_objfile->objfile_obstack,
					      comp_dir);
    }

  /* Save the debug format string (if any) in the symtab.  */
  COMPUNIT_DEBUGFORMAT (cu) = m_debugformat;

  /* Similarly for the producer.  */
  COMPUNIT_PRODUCER (cu) = m_producer;

  COMPUNIT_BLOCKVECTOR (cu) = blockvector;
  {
    struct block *b = BLOCKVECTOR_BLOCK (blockvector, GLOBAL_BLOCK);

    set_block_compunit_symtab (b, cu);
  }

  COMPUNIT_BLOCK_LINE_SECTION (cu) = section;

  COMPUNIT_MACRO_TABLE (cu) = release_macros ();

  /* Default any symbols without a specified symtab to the primary symtab.  */
  {
    int block_i;

    /* The main source file's symtab.  */
    struct symtab *symtab = COMPUNIT_FILETABS (cu);

    for (block_i = 0; block_i < BLOCKVECTOR_NBLOCKS (blockvector); block_i++)
      {
	struct block *block = BLOCKVECTOR_BLOCK (blockvector, block_i);
	struct symbol *sym;
	struct mdict_iterator miter;

	/* Inlined functions may have symbols not in the global or
	   static symbol lists.  */
	if (BLOCK_FUNCTION (block) != NULL)
	  if (symbol_symtab (BLOCK_FUNCTION (block)) == NULL)
	    symbol_set_symtab (BLOCK_FUNCTION (block), symtab);

	/* Note that we only want to fix up symbols from the local
	   blocks, not blocks coming from included symtabs.  That is why
	   we use ALL_DICT_SYMBOLS here and not ALL_BLOCK_SYMBOLS.  */
	ALL_DICT_SYMBOLS (BLOCK_MULTIDICT (block), miter, sym)
	  if (symbol_symtab (sym) == NULL)
	    symbol_set_symtab (sym, symtab);
      }
  }

  add_compunit_symtab_to_objfile (cu);

  return cu;
}

/* Implementation of the second part of end_symtab.  Pass STATIC_BLOCK
   as value returned by end_symtab_get_static_block.

   SECTION is the same as for end_symtab: the section number
   (in objfile->section_offsets) of the blockvector and linetable.

   If EXPANDABLE is non-zero the GLOBAL_BLOCK dictionary is made
   expandable.  */

struct compunit_symtab *
buildsym_compunit::end_symtab_from_static_block (struct block *static_block,
						 int section, int expandable)
{
  struct compunit_symtab *cu;

  if (static_block == NULL)
    {
      /* Handle the "no blockvector" case.
	 When this happens there is nothing to record, so there's nothing
	 to do: memory will be freed up later.

	 Note: We won't be adding a compunit to the objfile's list of
	 compunits, so there's nothing to unchain.  However, since each symtab
	 is added to the objfile's obstack we can't free that space.
	 We could do better, but this is believed to be a sufficiently rare
	 event.  */
      cu = NULL;
    }
  else
    cu = end_symtab_with_blockvector (static_block, section, expandable);

  return cu;
}

/* Finish the symbol definitions for one main source file, close off
   all the lexical contexts for that file (creating struct block's for
   them), then make the struct symtab for that file and put it in the
   list of all such.

   END_ADDR is the address of the end of the file's text.  SECTION is
   the section number (in objfile->section_offsets) of the blockvector
   and linetable.

   Note that it is possible for end_symtab() to return NULL.  In
   particular, for the DWARF case at least, it will return NULL when
   it finds a compilation unit that has exactly one DIE, a
   TAG_compile_unit DIE.  This can happen when we link in an object
   file that was compiled from an empty source file.  Returning NULL
   is probably not the correct thing to do, because then gdb will
   never know about this empty file (FIXME).

   If you need to modify STATIC_BLOCK before it is finalized you should
   call end_symtab_get_static_block and end_symtab_from_static_block
   yourself.  */

struct compunit_symtab *
buildsym_compunit::end_symtab (CORE_ADDR end_addr, int section)
{
  struct block *static_block;

  static_block = end_symtab_get_static_block (end_addr, 0, 0);
  return end_symtab_from_static_block (static_block, section, 0);
}

/* Same as end_symtab except create a symtab that can be later added to.  */

struct compunit_symtab *
buildsym_compunit::end_expandable_symtab (CORE_ADDR end_addr, int section)
{
  struct block *static_block;

  static_block = end_symtab_get_static_block (end_addr, 1, 0);
  return end_symtab_from_static_block (static_block, section, 1);
}

/* Subroutine of augment_type_symtab to simplify it.
   Attach the main source file's symtab to all symbols in PENDING_LIST that
   don't have one.  */

static void
set_missing_symtab (struct pending *pending_list,
		    struct compunit_symtab *cu)
{
  struct pending *pending;
  int i;

  for (pending = pending_list; pending != NULL; pending = pending->next)
    {
      for (i = 0; i < pending->nsyms; ++i)
	{
	  if (symbol_symtab (pending->symbol[i]) == NULL)
	    symbol_set_symtab (pending->symbol[i], COMPUNIT_FILETABS (cu));
	}
    }
}

/* Same as end_symtab, but for the case where we're adding more symbols
   to an existing symtab that is known to contain only type information.
   This is the case for DWARF4 Type Units.  */

void
buildsym_compunit::augment_type_symtab ()
{
  struct compunit_symtab *cust = m_compunit_symtab;
  const struct blockvector *blockvector = COMPUNIT_BLOCKVECTOR (cust);

  if (!m_context_stack.empty ())
    complaint (_("Context stack not empty in augment_type_symtab"));
  if (m_pending_blocks != NULL)
    complaint (_("Blocks in a type symtab"));
  if (m_pending_macros != NULL)
    complaint (_("Macro in a type symtab"));
  if (m_have_line_numbers)
    complaint (_("Line numbers recorded in a type symtab"));

  if (m_file_symbols != NULL)
    {
      struct block *block = BLOCKVECTOR_BLOCK (blockvector, STATIC_BLOCK);

      /* First mark any symbols without a specified symtab as belonging
	 to the primary symtab.  */
      set_missing_symtab (m_file_symbols, cust);

      mdict_add_pending (BLOCK_MULTIDICT (block), m_file_symbols);
    }

  if (m_global_symbols != NULL)
    {
      struct block *block = BLOCKVECTOR_BLOCK (blockvector, GLOBAL_BLOCK);

      /* First mark any symbols without a specified symtab as belonging
	 to the primary symtab.  */
      set_missing_symtab (m_global_symbols, cust);

      mdict_add_pending (BLOCK_MULTIDICT (block),
			m_global_symbols);
    }
}

/* Push a context block.  Args are an identifying nesting level
   (checkable when you pop it), and the starting PC address of this
   context.  */

struct context_stack *
buildsym_compunit::push_context (int desc, CORE_ADDR valu)
{
  m_context_stack.emplace_back ();
  struct context_stack *newobj = &m_context_stack.back ();

  newobj->depth = desc;
  newobj->locals = m_local_symbols;
  newobj->old_blocks = m_pending_blocks;
  newobj->start_addr = valu;
  newobj->local_using_directives = m_local_using_directives;
  newobj->name = NULL;

  m_local_symbols = NULL;
  m_local_using_directives = NULL;

  return newobj;
}

/* Pop a context block.  Returns the address of the context block just
   popped.  */

struct context_stack
buildsym_compunit::pop_context ()
{
  gdb_assert (!m_context_stack.empty ());
  struct context_stack result = m_context_stack.back ();
  m_context_stack.pop_back ();
  return result;
}