summaryrefslogtreecommitdiff
path: root/libdw/dwarf_getsrclines.c
blob: fe0e67d6a00142b9d2bbe87ac3f745ea02def5c5 (plain)
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
/* Return line number information of CU.
   Copyright (C) 2004-2009 Red Hat, Inc.
   This file is part of Red Hat elfutils.
   Written by Ulrich Drepper <drepper@redhat.com>, 2004.

   Red Hat elfutils 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; version 2 of the License.

   Red Hat elfutils 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 Red Hat elfutils; if not, write to the Free Software Foundation,
   Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.

   In addition, as a special exception, Red Hat, Inc. gives You the
   additional right to link the code of Red Hat elfutils with code licensed
   under any Open Source Initiative certified open source license
   (http://www.opensource.org/licenses/index.php) which requires the
   distribution of source code with any binary distribution and to
   distribute linked combinations of the two.  Non-GPL Code permitted under
   this exception must only link to the code of Red Hat elfutils through
   those well defined interfaces identified in the file named EXCEPTION
   found in the source code files (the "Approved Interfaces").  The files
   of Non-GPL Code may instantiate templates or use macros or inline
   functions from the Approved Interfaces without causing the resulting
   work to be covered by the GNU General Public License.  Only Red Hat,
   Inc. may make changes or additions to the list of Approved Interfaces.
   Red Hat's grant of this exception is conditioned upon your not adding
   any new exceptions.  If you wish to add a new Approved Interface or
   exception, please contact Red Hat.  You must obey the GNU General Public
   License in all respects for all of the Red Hat elfutils code and other
   code used in conjunction with Red Hat elfutils except the Non-GPL Code
   covered by this exception.  If you modify this file, you may extend this
   exception to your version of the file, but you are not obligated to do
   so.  If you do not wish to provide this exception without modification,
   you must delete this exception statement from your version and license
   this file solely under the GPL without exception.

   Red Hat elfutils is an included package of the Open Invention Network.
   An included package of the Open Invention Network is a package for which
   Open Invention Network licensees cross-license their patents.  No patent
   license is granted, either expressly or impliedly, by designation as an
   included package.  Should you wish to participate in the Open Invention
   Network licensing program, please visit www.openinventionnetwork.com
   <http://www.openinventionnetwork.com>.  */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include "dwarf.h"
#include "libdwP.h"


struct filelist
{
  Dwarf_Fileinfo info;
  struct filelist *next;
};

struct linelist
{
  Dwarf_Line line;
  struct linelist *next;
};


/* Compare by Dwarf_Line.addr, given pointers into an array of pointers.  */
static int
compare_lines (const void *a, const void *b)
{
  Dwarf_Line *const *p1 = a;
  Dwarf_Line *const *p2 = b;

  if ((*p1)->addr == (*p2)->addr)
    /* An end_sequence marker precedes a normal record at the same address.  */
    return (*p2)->end_sequence - (*p1)->end_sequence;

  return (*p1)->addr - (*p2)->addr;
}


/* Adds a new line to the matrix.  We cannot define a function because
   we want to use alloca.  */
#define NEW_LINE(end_seq) \
  do {									      \
    /* Add the new line.  */						      \
    new_line = (struct linelist *) alloca (sizeof (struct linelist));	      \
									      \
    /* Set the line information.  */					      \
    new_line->line.addr = address;					      \
    new_line->line.file = file;						      \
    new_line->line.line = line;						      \
    new_line->line.column = column;					      \
    new_line->line.is_stmt = is_stmt;					      \
    new_line->line.basic_block = basic_block;				      \
    new_line->line.end_sequence = end_seq;				      \
    new_line->line.prologue_end = prologue_end;				      \
    new_line->line.epilogue_begin = epilogue_begin;			      \
									      \
    new_line->next = linelist;						      \
    linelist = new_line;						      \
    ++nlinelist;							      \
  } while (0)


int
dwarf_getsrclines (Dwarf_Die *cudie, Dwarf_Lines **lines, size_t *nlines)
{
  if (unlikely (cudie == NULL
		|| INTUSE(dwarf_tag) (cudie) != DW_TAG_compile_unit))
    return -1;

  int res = -1;

  /* Get the information if it is not already known.  */
  struct Dwarf_CU *const cu = cudie->cu;
  if (cu->lines == NULL)
    {
      /* Failsafe mode: no data found.  */
      cu->lines = (void *) -1l;
      cu->files = (void *) -1l;

      /* The die must have a statement list associated.  */
      Dwarf_Attribute stmt_list_mem;
      Dwarf_Attribute *stmt_list = INTUSE(dwarf_attr) (cudie, DW_AT_stmt_list,
						       &stmt_list_mem);

      /* Get the offset into the .debug_line section.  NB: this call
	 also checks whether the previous dwarf_attr call failed.  */
      Dwarf_Word offset;
      if (INTUSE(dwarf_formudata) (stmt_list, &offset) != 0)
	goto out;

      Dwarf *dbg = cu->dbg;
      if (dbg->sectiondata[IDX_debug_line] == NULL)
	{
	  __libdw_seterrno (DWARF_E_NO_DEBUG_LINE);
	  goto out;
	}
      const uint8_t *linep = dbg->sectiondata[IDX_debug_line]->d_buf + offset;
      const uint8_t *lineendp = (dbg->sectiondata[IDX_debug_line]->d_buf
				 + dbg->sectiondata[IDX_debug_line]->d_size);

      /* Get the compilation directory.  */
      Dwarf_Attribute compdir_attr_mem;
      Dwarf_Attribute *compdir_attr = INTUSE(dwarf_attr) (cudie,
							  DW_AT_comp_dir,
							  &compdir_attr_mem);
      const char *comp_dir = INTUSE(dwarf_formstring) (compdir_attr);

      if (unlikely (linep + 4 > lineendp))
	{
	invalid_data:
	  __libdw_seterrno (DWARF_E_INVALID_DEBUG_LINE);
	  goto out;
	}
      Dwarf_Word unit_length = read_4ubyte_unaligned_inc (dbg, linep);
      unsigned int length = 4;
      if (unlikely (unit_length == DWARF3_LENGTH_64_BIT))
	{
	  if (unlikely (linep + 8 > lineendp))
	    goto invalid_data;
	  unit_length = read_8ubyte_unaligned_inc (dbg, linep);
	  length = 8;
	}

      /* Check whether we have enough room in the section.  */
      if (unit_length < 2 + length + 5 * 1
	  || unlikely (linep + unit_length > lineendp))
	goto invalid_data;
      lineendp = linep + unit_length;

      /* The next element of the header is the version identifier.  */
      uint_fast16_t version = read_2ubyte_unaligned_inc (dbg, linep);
      if (unlikely (version > DWARF_VERSION))
	{
	  __libdw_seterrno (DWARF_E_VERSION);
	  goto out;
	}

      /* Next comes the header length.  */
      Dwarf_Word header_length;
      if (length == 4)
	header_length = read_4ubyte_unaligned_inc (dbg, linep);
      else
	header_length = read_8ubyte_unaligned_inc (dbg, linep);
      const unsigned char *header_start = linep;

      /* Next the minimum instruction length.  */
      uint_fast8_t minimum_instr_len = *linep++;

        /* Then the flag determining the default value of the is_stmt
	   register.  */
      uint_fast8_t default_is_stmt = *linep++;

      /* Now the line base.  */
      int_fast8_t line_base = *((int_fast8_t *) linep);
      ++linep;

      /* And the line range.  */
      uint_fast8_t line_range = *linep++;

      /* The opcode base.  */
      uint_fast8_t opcode_base = *linep++;

      /* Remember array with the standard opcode length (-1 to account for
	 the opcode with value zero not being mentioned).  */
      const uint8_t *standard_opcode_lengths = linep - 1;
      linep += opcode_base - 1;
      if (unlikely (linep >= lineendp))
	goto invalid_data;

      /* First comes the list of directories.  Add the compilation
	 directory first since the index zero is used for it.  */
      struct dirlist
      {
	const char *dir;
	size_t len;
	struct dirlist *next;
      } comp_dir_elem =
	{
	  .dir = comp_dir,
	  .len = comp_dir ? strlen (comp_dir) : 0,
	  .next = NULL
	};
      struct dirlist *dirlist = &comp_dir_elem;
      unsigned int ndirlist = 1;

      // XXX Directly construct array to conserve memory?
      while (*linep != 0)
	{
	  struct dirlist *new_dir =
	    (struct dirlist *) alloca (sizeof (*new_dir));

	  new_dir->dir = (char *) linep;
	  uint8_t *endp = memchr (linep, '\0', lineendp - linep);
	  if (endp == NULL)
	    goto invalid_data;
	  new_dir->len = endp - linep;
	  new_dir->next = dirlist;
	  dirlist = new_dir;
	  ++ndirlist;
	  linep = endp + 1;
	}
      /* Skip the final NUL byte.  */
      ++linep;

      /* Rearrange the list in array form.  */
      struct dirlist **dirarray
	= (struct dirlist **) alloca (ndirlist * sizeof (*dirarray));
      for (unsigned int n = ndirlist; n-- > 0; dirlist = dirlist->next)
	dirarray[n] = dirlist;

      /* Now read the files.  */
      struct filelist null_file =
	{
	  .info =
	  {
	    .name = "???",
	    .mtime = 0,
	    .length = 0
	  },
	  .next = NULL
	};
      struct filelist *filelist = &null_file;
      unsigned int nfilelist = 1;

      if (unlikely (linep >= lineendp))
	goto invalid_data;
      while (*linep != 0)
	{
	  struct filelist *new_file =
	    (struct filelist *) alloca (sizeof (*new_file));

	  /* First comes the file name.  */
	  char *fname = (char *) linep;
	  uint8_t *endp = memchr (fname, '\0', lineendp - linep);
	  if (endp == NULL)
	    goto invalid_data;
	  size_t fnamelen = endp - (uint8_t *) fname;
	  linep = endp + 1;

	  /* Then the index.  */
	  Dwarf_Word diridx;
	  get_uleb128 (diridx, linep);
	  if (unlikely (diridx >= ndirlist))
	    {
	      __libdw_seterrno (DWARF_E_INVALID_DIR_IDX);
	      goto out;
	    }

	  if (*fname == '/')
	    /* It's an absolute path.  */
	    new_file->info.name = fname;
	  else
	    {
	      new_file->info.name = libdw_alloc (dbg, char, 1,
						 dirarray[diridx]->len + 1
						 + fnamelen + 1);
              char *cp = new_file->info.name;

              if (dirarray[diridx]->dir != NULL)
		{
		  /* This value could be NULL in case the DW_AT_comp_dir
		     was not present.  We cannot do much in this case.
		     The easiest thing is to convert the path in an
                   absolute path.  */
		  cp = stpcpy (cp, dirarray[diridx]->dir);
		}
              *cp++ = '/';
              strcpy (cp, fname);
	      assert (strlen (new_file->info.name)
		      < dirarray[diridx]->len + 1 + fnamelen + 1);
            }

	  /* Next comes the modification time.  */
	  get_uleb128 (new_file->info.mtime, linep);

	  /* Finally the length of the file.  */
	  get_uleb128 (new_file->info.length, linep);

	  new_file->next = filelist;
	  filelist = new_file;
	  ++nfilelist;
	}
      /* Skip the final NUL byte.  */
      ++linep;

      /* Consistency check.  */
      if (unlikely (linep != header_start + header_length))
	{
	  __libdw_seterrno (DWARF_E_INVALID_DWARF);
	  goto out;
	}

        /* We are about to process the statement program.  Initialize the
	   state machine registers (see 6.2.2 in the v2.1 specification).  */
      Dwarf_Word address = 0;
      size_t file = 1;
      size_t line = 1;
      size_t column = 0;
      uint_fast8_t is_stmt = default_is_stmt;
      int basic_block = 0;
      int prologue_end = 0;
      int epilogue_begin = 0;

        /* Process the instructions.  */
      struct linelist *linelist = NULL;
      unsigned int nlinelist = 0;
      while (linep < lineendp)
	{
	  struct linelist *new_line;
	  unsigned int opcode;
	  unsigned int u128;
	  int s128;

	  /* Read the opcode.  */
	  opcode = *linep++;

	  /* Is this a special opcode?  */
	  if (likely (opcode >= opcode_base))
	    {
	      /* Yes.  Handling this is quite easy since the opcode value
		 is computed with

		 opcode = (desired line increment - line_base)
		           + (line_range * address advance) + opcode_base
	      */
	      int line_increment = (line_base
				    + (opcode - opcode_base) % line_range);
	      unsigned int address_increment = (minimum_instr_len
						* ((opcode - opcode_base)
						   / line_range));

	      /* Perform the increments.  */
	      line += line_increment;
	      address += address_increment;

	      /* Add a new line with the current state machine values.  */
	      NEW_LINE (0);

	      /* Reset the flags.  */
	      basic_block = 0;
	      prologue_end = 0;
	      epilogue_begin = 0;
	    }
	  else if (opcode == 0)
	    {
	      /* This an extended opcode.  */
	      if (unlikely (linep + 2 > lineendp))
		goto invalid_data;

	      /* The length.  */
	      unsigned int len = *linep++;

	      if (unlikely (linep + len > lineendp))
		goto invalid_data;

	      /* The sub-opcode.  */
	      opcode = *linep++;

	      switch (opcode)
		{
		case DW_LNE_end_sequence:
		  /* Add a new line with the current state machine values.
		     The is the end of the sequence.  */
		  NEW_LINE (1);

		  /* Reset the registers.  */
		  address = 0;
		  file = 1;
		  line = 1;
		  column = 0;
		  is_stmt = default_is_stmt;
		  basic_block = 0;
		  prologue_end = 0;
		  epilogue_begin = 0;
		  break;

		case DW_LNE_set_address:
		  /* The value is an address.  The size is defined as
		     apporiate for the target machine.  We use the
		     address size field from the CU header.  */
		  if (cu->address_size == 4)
		    address = read_4ubyte_unaligned_inc (dbg, linep);
		  else
		    address = read_8ubyte_unaligned_inc (dbg, linep);
		  break;

		case DW_LNE_define_file:
		  {
		    char *fname = (char *) linep;
		    uint8_t *endp = memchr (linep, '\0', lineendp - linep);
		    if (endp == NULL)
		      goto invalid_data;
		    size_t fnamelen = endp - linep;
		    linep = endp + 1;

		    unsigned int diridx;
		    get_uleb128 (diridx, linep);
		    Dwarf_Word mtime;
		    get_uleb128 (mtime, linep);
		    Dwarf_Word filelength;
		    get_uleb128 (filelength, linep);

		    struct filelist *new_file =
		      (struct filelist *) alloca (sizeof (*new_file));
		    if (fname[0] == '/')
		      new_file->info.name = fname;
		    else
		      {
			new_file->info.name =
			  libdw_alloc (dbg, char, 1, (dirarray[diridx]->len + 1
						      + fnamelen + 1));
			char *cp = new_file->info.name;

			if (dirarray[diridx]->dir != NULL)
			  /* This value could be NULL in case the
			     DW_AT_comp_dir was not present.  We
			     cannot do much in this case.  The easiest
			     thing is to convert the path in an
			     absolute path.  */
			  cp = stpcpy (cp, dirarray[diridx]->dir);
			*cp++ = '/';
			strcpy (cp, fname);
		      }

		    new_file->info.mtime = mtime;
		    new_file->info.length = filelength;
		    new_file->next = filelist;
		    filelist = new_file;
		    ++nfilelist;
		  }
		  break;

		default:
		  /* Unknown, ignore it.  */
		  linep += len - 1;
		  break;
		}
	    }
	  else if (opcode <= DW_LNS_set_epilogue_begin)
	    {
	      /* This is a known standard opcode.  */
	      switch (opcode)
		{
		case DW_LNS_copy:
		  /* Takes no argument.  */
		  if (unlikely (standard_opcode_lengths[opcode] != 0))
		    goto invalid_data;

		  /* Add a new line with the current state machine values.  */
		  NEW_LINE (0);

		  /* Reset the flags.  */
		  basic_block = 0;
		  /* XXX Whether the following two lines are necessary is
		     unclear.  I guess the current v2.1 specification has
		     a bug in that it says clearing these two registers is
		     not necessary.  */
		  prologue_end = 0;
		  epilogue_begin = 0;
		  break;

		case DW_LNS_advance_pc:
		  /* Takes one uleb128 parameter which is added to the
		     address.  */
		  if (unlikely (standard_opcode_lengths[opcode] != 1))
		    goto invalid_data;

		  get_uleb128 (u128, linep);
		  address += minimum_instr_len * u128;
		  break;

		case DW_LNS_advance_line:
		  /* Takes one sleb128 parameter which is added to the
		     line.  */
		  if (unlikely (standard_opcode_lengths[opcode] != 1))
		    goto invalid_data;

		  get_sleb128 (s128, linep);
		  line += s128;
		  break;

		case DW_LNS_set_file:
		  /* Takes one uleb128 parameter which is stored in file.  */
		  if (unlikely (standard_opcode_lengths[opcode] != 1))
		    goto invalid_data;

		  get_uleb128 (u128, linep);
		  file = u128;
		  break;

		case DW_LNS_set_column:
		  /* Takes one uleb128 parameter which is stored in column.  */
		  if (unlikely (standard_opcode_lengths[opcode] != 1))
		    goto invalid_data;

		  get_uleb128 (u128, linep);
		  column = u128;
		  break;

		case DW_LNS_negate_stmt:
		  /* Takes no argument.  */
		  if (unlikely (standard_opcode_lengths[opcode] != 0))
		    goto invalid_data;

		  is_stmt = 1 - is_stmt;
		  break;

		case DW_LNS_set_basic_block:
		  /* Takes no argument.  */
		  if (unlikely (standard_opcode_lengths[opcode] != 0))
		    goto invalid_data;

		  basic_block = 1;
		  break;

		case DW_LNS_const_add_pc:
		  /* Takes no argument.  */
		  if (unlikely (standard_opcode_lengths[opcode] != 0))
		    goto invalid_data;

		  address += (minimum_instr_len
			      * ((255 - opcode_base) / line_range));
		  break;

		case DW_LNS_fixed_advance_pc:
		  /* Takes one 16 bit parameter which is added to the
		     address.  */
		  if (unlikely (standard_opcode_lengths[opcode] != 1))
		    goto invalid_data;

		  address += read_2ubyte_unaligned_inc (dbg, linep);
		  break;

		case DW_LNS_set_prologue_end:
		  /* Takes no argument.  */
		  if (unlikely (standard_opcode_lengths[opcode] != 0))
		    goto invalid_data;

		  prologue_end = 1;
		  break;

		case DW_LNS_set_epilogue_begin:
		  /* Takes no argument.  */
		  if (unlikely (standard_opcode_lengths[opcode] != 0))
		    goto invalid_data;

		  epilogue_begin = 1;
		  break;
		}
	    }
	  else
	    {
	      /* This is a new opcode the generator but not we know about.
		 Read the parameters associated with it but then discard
		 everything.  Read all the parameters for this opcode.  */
	      for (int n = standard_opcode_lengths[opcode]; n > 0; --n)
		get_uleb128 (u128, linep);

	      /* Next round, ignore this opcode.  */
	      continue;
	    }
	}

      /* Put all the files in an array.  */
      Dwarf_Files *files = libdw_alloc (dbg, Dwarf_Files,
					sizeof (Dwarf_Files)
					+ nfilelist * sizeof (Dwarf_Fileinfo)
					+ (ndirlist + 1) * sizeof (char *),
					1);
      const char **dirs = (void *) &files->info[nfilelist];

      files->nfiles = nfilelist;
      while (nfilelist-- > 0)
	{
	  files->info[nfilelist] = filelist->info;
	  filelist = filelist->next;
	}
      assert (filelist == NULL);

      /* Put all the directory strings in an array.  */
      files->ndirs = ndirlist;
      for (unsigned int i = 0; i < ndirlist; ++i)
	dirs[i] = dirarray[i]->dir;
      dirs[ndirlist] = NULL;

      /* Remember the referring CU.  */
      files->cu = cu;

      /* Make the file data structure available through the CU.  */
      cu->files = files;

      void *buf = libdw_alloc (dbg, Dwarf_Lines, (sizeof (Dwarf_Lines)
						  + (sizeof (Dwarf_Line)
						     * nlinelist)), 1);

      /* First use the buffer for the pointers, and sort the entries.
	 We'll write the pointers in the end of the buffer, and then
	 copy into the buffer from the beginning so the overlap works.  */
      assert (sizeof (Dwarf_Line) >= sizeof (Dwarf_Line *));
      Dwarf_Line **sortlines = (buf + sizeof (Dwarf_Lines)
				+ ((sizeof (Dwarf_Line)
				    - sizeof (Dwarf_Line *)) * nlinelist));

      /* The list is in LIFO order and usually they come in clumps with
	 ascending addresses.  So fill from the back to probably start with
	 runs already in order before we sort.  */
      unsigned int i = nlinelist;
      while (i-- > 0)
	{
	  sortlines[i] = &linelist->line;
	  linelist = linelist->next;
	}
      assert (linelist == NULL);

      /* Sort by ascending address.  */
      qsort (sortlines, nlinelist, sizeof sortlines[0], &compare_lines);

      /* Now that they are sorted, put them in the final array.
	 The buffers overlap, so we've clobbered the early elements
	 of SORTLINES by the time we're reading the later ones.  */
      cu->lines = buf;
      cu->lines->nlines = nlinelist;
      for (i = 0; i < nlinelist; ++i)
	{
	  cu->lines->info[i] = *sortlines[i];
	  cu->lines->info[i].files = files;
	}

      /* Success.  */
      res = 0;
    }
  else if (cu->lines != (void *) -1l)
    /* We already have the information.  */
    res = 0;

  if (likely (res == 0))
    {
      *lines = cu->lines;
      *nlines = cu->lines->nlines;
    }
 out:

  // XXX Eventually: unlocking here.

  return res;
}
INTDEF(dwarf_getsrclines)