aboutsummaryrefslogtreecommitdiff
path: root/gas/stabs.c
blob: 3b56a4872d14b7a0a96d24783d8c49f84df7bdfd (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
699
700
701
702
703
704
705
706
707
708
709
710
711
/* Generic stabs parsing for gas.
   Copyright (C) 1989-2016 Free Software Foundation, Inc.

   This file is part of GAS, the GNU Assembler.

   GAS 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,
   or (at your option) any later version.

   GAS 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 GAS; see the file COPYING.  If not, write to the Free
   Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
   02110-1301, USA.  */

#include "as.h"
#include "filenames.h"
#include "obstack.h"
#include "subsegs.h"
#include "ecoff.h"

/* We need this, despite the apparent object format dependency, since
   it defines stab types, which all object formats can use now.  */

#include "aout/stab_gnu.h"

/* Holds whether the assembler is generating stabs line debugging
   information or not.  Potentially used by md_cleanup function.  */

int outputting_stabs_line_debug = 0;

static void s_stab_generic (int, const char *, const char *);
static void generate_asm_file (int, char *);

/* Allow backends to override the names used for the stab sections.  */
#ifndef STAB_SECTION_NAME
#define STAB_SECTION_NAME ".stab"
#endif

#ifndef STAB_STRING_SECTION_NAME
#define STAB_STRING_SECTION_NAME ".stabstr"
#endif

/* Non-zero if we're in the middle of a .func function, in which case
   stabs_generate_asm_lineno emits function relative line number stabs.
   Otherwise it emits line number stabs with absolute addresses.  Note that
   both cases only apply to assembler code assembled with -gstabs.  */
static int in_dot_func_p;

/* Label at start of current function if in_dot_func_p != 0.  */
static const char *current_function_label;

/*
 * Handle .stabX directives, which used to be open-coded.
 * So much creeping featurism overloaded the semantics that we decided
 * to put all .stabX thinking in one place. Here.
 *
 * We try to make any .stabX directive legal. Other people's AS will often
 * do assembly-time consistency checks: eg assigning meaning to n_type bits
 * and "protecting" you from setting them to certain values. (They also zero
 * certain bits before emitting symbols. Tut tut.)
 *
 * If an expression is not absolute we either gripe or use the relocation
 * information. Other people's assemblers silently forget information they
 * don't need and invent information they need that you didn't supply.
 */

/*
 * Build a string dictionary entry for a .stabX symbol.
 * The symbol is added to the .<secname>str section.
 */

#ifndef SEPARATE_STAB_SECTIONS
#define SEPARATE_STAB_SECTIONS 0
#endif

unsigned int
get_stab_string_offset (const char *string, const char *stabstr_secname)
{
  unsigned int length;
  unsigned int retval;
  segT save_seg;
  subsegT save_subseg;
  segT seg;
  char *p;

  if (! SEPARATE_STAB_SECTIONS)
    abort ();

  length = strlen (string);

  save_seg = now_seg;
  save_subseg = now_subseg;

  /* Create the stab string section.  */
  seg = subseg_new (stabstr_secname, 0);

  retval = seg_info (seg)->stabu.stab_string_size;
  if (retval <= 0)
    {
      /* Make sure the first string is empty.  */
      p = frag_more (1);
      *p = 0;
      retval = seg_info (seg)->stabu.stab_string_size = 1;
      bfd_set_section_flags (stdoutput, seg, SEC_READONLY | SEC_DEBUGGING);
      if (seg->name == stabstr_secname)
	seg->name = xstrdup (stabstr_secname);
    }

  if (length > 0)
    {				/* Ordinary case.  */
      p = frag_more (length + 1);
      strcpy (p, string);

      seg_info (seg)->stabu.stab_string_size += length + 1;
    }
  else
    retval = 0;

  subseg_set (save_seg, save_subseg);

  return retval;
}

#ifdef AOUT_STABS
#ifndef OBJ_PROCESS_STAB
#define OBJ_PROCESS_STAB(SEG,W,S,T,O,D)	aout_process_stab(W,S,T,O,D)
#endif

/* Here instead of obj-aout.c because other formats use it too.  */
void
aout_process_stab (what, string, type, other, desc)
     int what;
     const char *string;
     int type, other, desc;
{
  /* Put the stab information in the symbol table.  */
  symbolS *symbol;

  /* Create the symbol now, but only insert it into the symbol chain
     after any symbols mentioned in the value expression get into the
     symbol chain.  This is to avoid "continuation symbols" (where one
     ends in "\" and the debug info is continued in the next .stabs
     directive) from being separated by other random symbols.  */
  symbol = symbol_create (string, undefined_section, 0,
			  &zero_address_frag);
  if (what == 's' || what == 'n')
    {
      /* Pick up the value from the input line.  */
      pseudo_set (symbol);
    }
  else
    {
      /* .stabd sets the name to NULL.  Why?  */
      S_SET_NAME (symbol, NULL);
      symbol_set_frag (symbol, frag_now);
      S_SET_VALUE (symbol, (valueT) frag_now_fix ());
    }

  symbol_append (symbol, symbol_lastP, &symbol_rootP, &symbol_lastP);

  symbol_get_bfdsym (symbol)->flags |= BSF_DEBUGGING;

  S_SET_TYPE (symbol, type);
  S_SET_OTHER (symbol, other);
  S_SET_DESC (symbol, desc);
}
#endif

/* This can handle different kinds of stabs (s,n,d) and different
   kinds of stab sections.  */

static void
s_stab_generic (int          what,
		const char * stab_secname,
	       	const char * stabstr_secname)
{
  long longint;
  const char *string;
  char *saved_string_obstack_end;
  int type;
  int other;
  int desc;

  /* The general format is:
     .stabs "STRING",TYPE,OTHER,DESC,VALUE
     .stabn TYPE,OTHER,DESC,VALUE
     .stabd TYPE,OTHER,DESC
     At this point input_line_pointer points after the pseudo-op and
     any trailing whitespace.  The argument what is one of 's', 'n' or
     'd' indicating which type of .stab this is.  */

  if (what != 's')
    {
      string = "";
      saved_string_obstack_end = 0;
    }
  else
    {
      int length;

      string = demand_copy_C_string (&length);
      /* FIXME: We should probably find some other temporary storage
	 for string, rather than leaking memory if someone else
	 happens to use the notes obstack.  */
      saved_string_obstack_end = notes.next_free;
      SKIP_WHITESPACE ();
      if (*input_line_pointer == ',')
	input_line_pointer++;
      else
	{
	  as_warn (_(".stab%c: missing comma"), what);
	  ignore_rest_of_line ();
	  return;
	}
    }

  if (get_absolute_expression_and_terminator (&longint) != ',')
    {
      as_warn (_(".stab%c: missing comma"), what);
      ignore_rest_of_line ();
      return;
    }
  type = longint;

  if (get_absolute_expression_and_terminator (&longint) != ',')
    {
      as_warn (_(".stab%c: missing comma"), what);
      ignore_rest_of_line ();
      return;
    }
  other = longint;

  desc = get_absolute_expression ();

  if ((desc > 0xffff) || (desc < -0x8000))
    /* This could happen for example with a source file with a huge
       number of lines.  The only cure is to use a different debug
       format, probably DWARF.  */
    as_warn (_(".stab%c: description field '%x' too big, try a different debug format"),
	     what, desc);

  if (what == 's' || what == 'n')
    {
      if (*input_line_pointer != ',')
	{
	  as_warn (_(".stab%c: missing comma"), what);
	  ignore_rest_of_line ();
	  return;
	}
      input_line_pointer++;
      SKIP_WHITESPACE ();
    }

#ifdef TC_PPC
#ifdef OBJ_ELF
  /* Solaris on PowerPC has decided that .stabd can take 4 arguments, so if we were
     given 4 arguments, make it a .stabn */
  else if (what == 'd')
    {
      char *save_location = input_line_pointer;

      SKIP_WHITESPACE ();
      if (*input_line_pointer == ',')
	{
	  input_line_pointer++;
	  what = 'n';
	}
      else
	input_line_pointer = save_location;
    }
#endif /* OBJ_ELF */
#endif /* TC_PPC */

#ifndef NO_LISTING
  if (listing)
    {
      switch (type)
	{
	case N_SLINE:
	  listing_source_line ((unsigned int) desc);
	  break;
	case N_SO:
	case N_SOL:
	  listing_source_file (string);
	  break;
	}
    }
#endif /* ! NO_LISTING */

  /* We have now gathered the type, other, and desc information.  For
     .stabs or .stabn, input_line_pointer is now pointing at the
     value.  */

  if (SEPARATE_STAB_SECTIONS)
    /* Output the stab information in a separate section.  This is used
       at least for COFF and ELF.  */
    {
      segT saved_seg = now_seg;
      subsegT saved_subseg = now_subseg;
      fragS *saved_frag = frag_now;
      valueT dot;
      segT seg;
      unsigned int stroff;
      char *p;

      static segT cached_sec;
      static char *cached_secname;

      dot = frag_now_fix ();

#ifdef md_flush_pending_output
      md_flush_pending_output ();
#endif

      if (cached_secname && !strcmp (cached_secname, stab_secname))
	{
	  seg = cached_sec;
	  subseg_set (seg, 0);
	}
      else
	{
	  seg = subseg_new (stab_secname, 0);
	  if (cached_secname)
	    free (cached_secname);
	  cached_secname = xstrdup (stab_secname);
	  cached_sec = seg;
	}

      if (! seg_info (seg)->hadone)
	{
	  bfd_set_section_flags (stdoutput, seg,
				 SEC_READONLY | SEC_RELOC | SEC_DEBUGGING);
#ifdef INIT_STAB_SECTION
	  INIT_STAB_SECTION (seg);
#endif
	  seg_info (seg)->hadone = 1;
	}

      stroff = get_stab_string_offset (string, stabstr_secname);
      if (what == 's')
	{
	  /* Release the string, if nobody else has used the obstack.  */
	  if (saved_string_obstack_end == notes.next_free)
	    obstack_free (&notes, string);
	}

      /* At least for now, stabs in a special stab section are always
	 output as 12 byte blocks of information.  */
      p = frag_more (8);
      md_number_to_chars (p, (valueT) stroff, 4);
      md_number_to_chars (p + 4, (valueT) type, 1);
      md_number_to_chars (p + 5, (valueT) other, 1);
      md_number_to_chars (p + 6, (valueT) desc, 2);

      if (what == 's' || what == 'n')
	{
	  /* Pick up the value from the input line.  */
	  cons (4);
	  input_line_pointer--;
	}
      else
	{
	  symbolS *symbol;
	  expressionS exp;

	  /* Arrange for a value representing the current location.  */
	  symbol = symbol_temp_new (saved_seg, dot, saved_frag);

	  exp.X_op = O_symbol;
	  exp.X_add_symbol = symbol;
	  exp.X_add_number = 0;

	  emit_expr (&exp, 4);
	}

#ifdef OBJ_PROCESS_STAB
      OBJ_PROCESS_STAB (seg, what, string, type, other, desc);
#endif

      subseg_set (saved_seg, saved_subseg);
    }
  else
    {
#ifdef OBJ_PROCESS_STAB
      OBJ_PROCESS_STAB (0, what, string, type, other, desc);
#else
      abort ();
#endif
    }

  demand_empty_rest_of_line ();
}

/* Regular stab directive.  */

void
s_stab (int what)
{
  s_stab_generic (what, STAB_SECTION_NAME, STAB_STRING_SECTION_NAME);
}

/* "Extended stabs", used in Solaris only now.  */

void
s_xstab (int what)
{
  int length;
  char *stab_secname, *stabstr_secname;
  static char *saved_secname, *saved_strsecname;

  /* @@ MEMORY LEAK: This allocates a copy of the string, but in most
     cases it will be the same string, so we could release the storage
     back to the obstack it came from.  */
  stab_secname = demand_copy_C_string (&length);
  SKIP_WHITESPACE ();
  if (*input_line_pointer == ',')
    input_line_pointer++;
  else
    {
      as_bad (_("comma missing in .xstabs"));
      ignore_rest_of_line ();
      return;
    }

  /* To get the name of the stab string section, simply add "str" to
     the stab section name.  */
  if (saved_secname == 0 || strcmp (saved_secname, stab_secname))
    {
      stabstr_secname = (char *) xmalloc (strlen (stab_secname) + 4);
      strcpy (stabstr_secname, stab_secname);
      strcat (stabstr_secname, "str");
      if (saved_secname)
	{
	  free (saved_secname);
	  free (saved_strsecname);
	}
      saved_secname = stab_secname;
      saved_strsecname = stabstr_secname;
    }
  s_stab_generic (what, saved_secname, saved_strsecname);
}

#ifdef S_SET_DESC

/* Frob invented at RMS' request. Set the n_desc of a symbol.  */

void
s_desc (ignore)
     int ignore ATTRIBUTE_UNUSED;
{
  char *name;
  char c;
  char *p;
  symbolS *symbolP;
  int temp;

  c = get_symbol_name (&name);
  p = input_line_pointer;
  *p = c;
  SKIP_WHITESPACE_AFTER_NAME ();
  if (*input_line_pointer != ',')
    {
      *p = 0;
      as_bad (_("expected comma after \"%s\""), name);
      *p = c;
      ignore_rest_of_line ();
    }
  else
    {
      input_line_pointer++;
      temp = get_absolute_expression ();
      *p = 0;
      symbolP = symbol_find_or_make (name);
      *p = c;
      S_SET_DESC (symbolP, temp);
    }
  demand_empty_rest_of_line ();
}				/* s_desc() */

#endif /* defined (S_SET_DESC) */

/* Generate stabs debugging information to denote the main source file.  */

void
stabs_generate_asm_file (void)
{
  char *file;
  unsigned int lineno;

  as_where (&file, &lineno);
  if (use_gnu_debug_info_extensions)
    {
      const char *dir;
      char *dir2;

      dir = remap_debug_filename (getpwd ());
      dir2 = (char *) alloca (strlen (dir) + 2);
      sprintf (dir2, "%s%s", dir, "/");
      generate_asm_file (N_SO, dir2);
      xfree ((char *) dir);
    }
  generate_asm_file (N_SO, file);
}

/* Generate stabs debugging information to denote the source file.
   TYPE is one of N_SO, N_SOL.  */

static void
generate_asm_file (int type, char *file)
{
  static char *last_file;
  static int label_count;
  char *hold;
  char sym[30];
  char *buf;
  char *tmp = file;
  char *file_endp = file + strlen (file);
  char *bufp;

  if (last_file != NULL
      && filename_cmp (last_file, file) == 0)
    return;

  /* Rather than try to do this in some efficient fashion, we just
     generate a string and then parse it again.  That lets us use the
     existing stabs hook, which expect to see a string, rather than
     inventing new ones.  */
  hold = input_line_pointer;

  sprintf (sym, "%sF%d", FAKE_LABEL_NAME, label_count);
  ++label_count;

  /* Allocate enough space for the file name (possibly extended with
     doubled up backslashes), the symbol name, and the other characters
     that make up a stabs file directive.  */
  bufp = buf = (char *) xmalloc (2 * strlen (file) + strlen (sym) + 12);

  *bufp++ = '"';

  while (tmp < file_endp)
    {
      char *bslash = strchr (tmp, '\\');
      size_t len = (bslash) ? (size_t) (bslash - tmp + 1) : strlen (tmp);

      /* Double all backslashes, since demand_copy_C_string (used by
	 s_stab to extract the part in quotes) will try to replace them as
	 escape sequences.  backslash may appear in a filespec.  */
      strncpy (bufp, tmp, len);

      tmp += len;
      bufp += len;

      if (bslash != NULL)
	*bufp++ = '\\';
    }

  sprintf (bufp, "\",%d,0,0,%s\n", type, sym);

  input_line_pointer = buf;
  s_stab ('s');
  colon (sym);

  if (last_file != NULL)
    free (last_file);
  last_file = xstrdup (file);

  free (buf);

  input_line_pointer = hold;
}

/* Generate stabs debugging information for the current line.  This is
   used to produce debugging information for an assembler file.  */

void
stabs_generate_asm_lineno (void)
{
  static int label_count;
  char *hold;
  char *file;
  unsigned int lineno;
  char *buf;
  char sym[30];
  /* Remember the last file/line and avoid duplicates.  */
  static unsigned int prev_lineno = -1;
  static char *prev_file = NULL;

  /* Rather than try to do this in some efficient fashion, we just
     generate a string and then parse it again.  That lets us use the
     existing stabs hook, which expect to see a string, rather than
     inventing new ones.  */

  hold = input_line_pointer;

  as_where (&file, &lineno);

  /* Don't emit sequences of stabs for the same line.  */
  if (prev_file == NULL)
    {
      /* First time thru.  */
      prev_file = xstrdup (file);
      prev_lineno = lineno;
    }
  else if (lineno == prev_lineno
	   && filename_cmp (file, prev_file) == 0)
    {
      /* Same file/line as last time.  */
      return;
    }
  else
    {
      /* Remember file/line for next time.  */
      prev_lineno = lineno;
      if (filename_cmp (file, prev_file) != 0)
	{
	  free (prev_file);
	  prev_file = xstrdup (file);
	}
    }

  /* Let the world know that we are in the middle of generating a
     piece of stabs line debugging information.  */
  outputting_stabs_line_debug = 1;

  generate_asm_file (N_SOL, file);

  sprintf (sym, "%sL%d", FAKE_LABEL_NAME, label_count);
  ++label_count;

  if (in_dot_func_p)
    {
      buf = (char *) alloca (100 + strlen (current_function_label));
      sprintf (buf, "%d,0,%d,%s-%s\n", N_SLINE, lineno,
	       sym, current_function_label);
    }
  else
    {
      buf = (char *) alloca (100);
      sprintf (buf, "%d,0,%d,%s\n", N_SLINE, lineno, sym);
    }
  input_line_pointer = buf;
  s_stab ('n');
  colon (sym);

  input_line_pointer = hold;
  outputting_stabs_line_debug = 0;
}

/* Emit a function stab.
   All assembler functions are assumed to have return type `void'.  */

void
stabs_generate_asm_func (const char *funcname, const char *startlabname)
{
  static int void_emitted_p;
  char *hold = input_line_pointer;
  char *buf;
  char *file;
  unsigned int lineno;

  if (! void_emitted_p)
    {
      input_line_pointer = "\"void:t1=1\",128,0,0,0";
      s_stab ('s');
      void_emitted_p = 1;
    }

  as_where (&file, &lineno);
  if (asprintf (&buf, "\"%s:F1\",%d,0,%d,%s",
		funcname, N_FUN, lineno + 1, startlabname) == -1)
    as_fatal ("%s", xstrerror (errno));
  input_line_pointer = buf;
  s_stab ('s');
  free (buf);

  input_line_pointer = hold;
  current_function_label = xstrdup (startlabname);
  in_dot_func_p = 1;
}

/* Emit a stab to record the end of a function.  */

void
stabs_generate_asm_endfunc (const char *funcname ATTRIBUTE_UNUSED,
			    const char *startlabname)
{
  static int label_count;
  char *hold = input_line_pointer;
  char *buf;
  char sym[30];

  sprintf (sym, "%sendfunc%d", FAKE_LABEL_NAME, label_count);
  ++label_count;
  colon (sym);

  if (asprintf (&buf, "\"\",%d,0,0,%s-%s", N_FUN, sym, startlabname) == -1)
    as_fatal ("%s", xstrerror (errno));
  input_line_pointer = buf;
  s_stab ('s');
  free (buf);

  input_line_pointer = hold;
  in_dot_func_p = 0;
  current_function_label = NULL;
}