1/* rddbg.c -- Read debugging information into a generic form.
2   Copyright 1995, 1996, 1997, 2000, 2002, 2003, 2005
3   Free Software Foundation, Inc.
4   Written by Ian Lance Taylor <ian@cygnus.com>.
5
6   This file is part of GNU Binutils.
7
8   This program is free software; you can redistribute it and/or modify
9   it under the terms of the GNU General Public License as published by
10   the Free Software Foundation; either version 2 of the License, or
11   (at your option) any later version.
12
13   This program is distributed in the hope that it will be useful,
14   but WITHOUT ANY WARRANTY; without even the implied warranty of
15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16   GNU General Public License for more details.
17
18   You should have received a copy of the GNU General Public License
19   along with this program; if not, write to the Free Software
20   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
21   02110-1301, USA.  */
22
23/* This file reads debugging information into a generic form.  This
24   file knows how to dig the debugging information out of an object
25   file.  */
26
27#include "bfd.h"
28#include "bucomm.h"
29#include "libiberty.h"
30#include "debug.h"
31#include "budbg.h"
32
33static bfd_boolean read_section_stabs_debugging_info
34  (bfd *, asymbol **, long, void *, bfd_boolean *);
35static bfd_boolean read_symbol_stabs_debugging_info
36  (bfd *, asymbol **, long, void *, bfd_boolean *);
37static bfd_boolean read_ieee_debugging_info (bfd *, void *, bfd_boolean *);
38static void save_stab (int, int, bfd_vma, const char *);
39static void stab_context (void);
40static void free_saved_stabs (void);
41
42/* Read debugging information from a BFD.  Returns a generic debugging
43   pointer.  */
44
45void *
46read_debugging_info (bfd *abfd, asymbol **syms, long symcount)
47{
48  void *dhandle;
49  bfd_boolean found;
50
51  dhandle = debug_init ();
52  if (dhandle == NULL)
53    return NULL;
54
55  if (! read_section_stabs_debugging_info (abfd, syms, symcount, dhandle,
56					   &found))
57    return NULL;
58
59  if (bfd_get_flavour (abfd) == bfd_target_aout_flavour)
60    {
61      if (! read_symbol_stabs_debugging_info (abfd, syms, symcount, dhandle,
62					      &found))
63	return NULL;
64    }
65
66  if (bfd_get_flavour (abfd) == bfd_target_ieee_flavour)
67    {
68      if (! read_ieee_debugging_info (abfd, dhandle, &found))
69	return NULL;
70    }
71
72  /* Try reading the COFF symbols if we didn't find any stabs in COFF
73     sections.  */
74  if (! found
75      && bfd_get_flavour (abfd) == bfd_target_coff_flavour
76      && symcount > 0)
77    {
78      if (! parse_coff (abfd, syms, symcount, dhandle))
79	return NULL;
80      found = TRUE;
81    }
82
83  if (! found)
84    {
85      non_fatal (_("%s: no recognized debugging information"),
86		 bfd_get_filename (abfd));
87      return NULL;
88    }
89
90  return dhandle;
91}
92
93/* Read stabs in sections debugging information from a BFD.  */
94
95static bfd_boolean
96read_section_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount,
97				   void *dhandle, bfd_boolean *pfound)
98{
99  static struct
100    {
101      const char *secname;
102      const char *strsecname;
103    }
104  names[] =
105    {
106      { ".stab", ".stabstr" },
107      { "LC_SYMTAB.stabs", "LC_SYMTAB.stabstr" },
108      { "$GDB_SYMBOLS$", "$GDB_STRINGS$" }
109    };
110  unsigned int i;
111  void *shandle;
112
113  *pfound = FALSE;
114  shandle = NULL;
115
116  for (i = 0; i < sizeof names / sizeof names[0]; i++)
117    {
118      asection *sec, *strsec;
119
120      sec = bfd_get_section_by_name (abfd, names[i].secname);
121      strsec = bfd_get_section_by_name (abfd, names[i].strsecname);
122      if (sec != NULL && strsec != NULL)
123	{
124	  bfd_size_type stabsize, strsize;
125	  bfd_byte *stabs, *strings;
126	  bfd_byte *stab;
127	  bfd_size_type stroff, next_stroff;
128
129	  stabsize = bfd_section_size (abfd, sec);
130	  stabs = (bfd_byte *) xmalloc (stabsize);
131	  if (! bfd_get_section_contents (abfd, sec, stabs, 0, stabsize))
132	    {
133	      fprintf (stderr, "%s: %s: %s\n",
134		       bfd_get_filename (abfd), names[i].secname,
135		       bfd_errmsg (bfd_get_error ()));
136	      return FALSE;
137	    }
138
139	  strsize = bfd_section_size (abfd, strsec);
140	  strings = (bfd_byte *) xmalloc (strsize);
141	  if (! bfd_get_section_contents (abfd, strsec, strings, 0, strsize))
142	    {
143	      fprintf (stderr, "%s: %s: %s\n",
144		       bfd_get_filename (abfd), names[i].strsecname,
145		       bfd_errmsg (bfd_get_error ()));
146	      return FALSE;
147	    }
148
149	  if (shandle == NULL)
150	    {
151	      shandle = start_stab (dhandle, abfd, TRUE, syms, symcount);
152	      if (shandle == NULL)
153		return FALSE;
154	    }
155
156	  *pfound = TRUE;
157
158	  stroff = 0;
159	  next_stroff = 0;
160	  for (stab = stabs; stab < stabs + stabsize; stab += 12)
161	    {
162	      unsigned int strx;
163	      int type;
164	      int other;
165	      int desc;
166	      bfd_vma value;
167
168	      /* This code presumes 32 bit values.  */
169
170	      strx = bfd_get_32 (abfd, stab);
171	      type = bfd_get_8 (abfd, stab + 4);
172	      other = bfd_get_8 (abfd, stab + 5);
173	      desc = bfd_get_16 (abfd, stab + 6);
174	      value = bfd_get_32 (abfd, stab + 8);
175
176	      if (type == 0)
177		{
178		  /* Special type 0 stabs indicate the offset to the
179		     next string table.  */
180		  stroff = next_stroff;
181		  next_stroff += value;
182		}
183	      else
184		{
185		  char *f, *s;
186
187		  f = NULL;
188
189		  if (stroff + strx > strsize)
190		    {
191		      fprintf (stderr, "%s: %s: stab entry %ld is corrupt, strx = 0x%x, type = %d\n",
192			       bfd_get_filename (abfd), names[i].secname,
193			       (long) (stab - stabs) / 12, strx, type);
194		      continue;
195		    }
196
197		  s = (char *) strings + stroff + strx;
198
199		  while (s[strlen (s) - 1] == '\\'
200			 && stab + 12 < stabs + stabsize)
201		    {
202		      char *p;
203
204		      stab += 12;
205		      p = s + strlen (s) - 1;
206		      *p = '\0';
207		      s = concat (s,
208				  ((char *) strings
209				   + stroff
210				   + bfd_get_32 (abfd, stab)),
211				  (const char *) NULL);
212
213		      /* We have to restore the backslash, because, if
214			 the linker is hashing stabs strings, we may
215			 see the same string more than once.  */
216		      *p = '\\';
217
218		      if (f != NULL)
219			free (f);
220		      f = s;
221		    }
222
223		  save_stab (type, desc, value, s);
224
225		  if (! parse_stab (dhandle, shandle, type, desc, value, s))
226		    {
227		      stab_context ();
228		      free_saved_stabs ();
229		      return FALSE;
230		    }
231
232		  /* Don't free f, since I think the stabs code
233		     expects strings to hang around.  This should be
234		     straightened out.  FIXME.  */
235		}
236	    }
237
238	  free_saved_stabs ();
239	  free (stabs);
240
241	  /* Don't free strings, since I think the stabs code expects
242	     the strings to hang around.  This should be straightened
243	     out.  FIXME.  */
244	}
245    }
246
247  if (shandle != NULL)
248    {
249      if (! finish_stab (dhandle, shandle))
250	return FALSE;
251    }
252
253  return TRUE;
254}
255
256/* Read stabs in the symbol table.  */
257
258static bfd_boolean
259read_symbol_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount,
260				  void *dhandle, bfd_boolean *pfound)
261{
262  void *shandle;
263  asymbol **ps, **symend;
264
265  shandle = NULL;
266  symend = syms + symcount;
267  for (ps = syms; ps < symend; ps++)
268    {
269      symbol_info i;
270
271      bfd_get_symbol_info (abfd, *ps, &i);
272
273      if (i.type == '-')
274	{
275	  const char *s;
276	  char *f;
277
278	  if (shandle == NULL)
279	    {
280	      shandle = start_stab (dhandle, abfd, FALSE, syms, symcount);
281	      if (shandle == NULL)
282		return FALSE;
283	    }
284
285	  *pfound = TRUE;
286
287	  s = i.name;
288	  f = NULL;
289	  while (s[strlen (s) - 1] == '\\'
290		 && ps + 1 < symend)
291	    {
292	      char *sc, *n;
293
294	      ++ps;
295	      sc = xstrdup (s);
296	      sc[strlen (sc) - 1] = '\0';
297	      n = concat (sc, bfd_asymbol_name (*ps), (const char *) NULL);
298	      free (sc);
299	      if (f != NULL)
300		free (f);
301	      f = n;
302	      s = n;
303	    }
304
305	  save_stab (i.stab_type, i.stab_desc, i.value, s);
306
307	  if (! parse_stab (dhandle, shandle, i.stab_type, i.stab_desc,
308			    i.value, s))
309	    {
310	      stab_context ();
311	      free_saved_stabs ();
312	      return FALSE;
313	    }
314
315	  /* Don't free f, since I think the stabs code expects
316	     strings to hang around.  This should be straightened out.
317	     FIXME.  */
318	}
319    }
320
321  free_saved_stabs ();
322
323  if (shandle != NULL)
324    {
325      if (! finish_stab (dhandle, shandle))
326	return FALSE;
327    }
328
329  return TRUE;
330}
331
332/* Read IEEE debugging information.  */
333
334static bfd_boolean
335read_ieee_debugging_info (bfd *abfd, void *dhandle, bfd_boolean *pfound)
336{
337  asection *dsec;
338  bfd_size_type size;
339  bfd_byte *contents;
340
341  /* The BFD backend puts the debugging information into a section
342     named .debug.  */
343
344  dsec = bfd_get_section_by_name (abfd, ".debug");
345  if (dsec == NULL)
346    return TRUE;
347
348  size = bfd_section_size (abfd, dsec);
349  contents = (bfd_byte *) xmalloc (size);
350  if (! bfd_get_section_contents (abfd, dsec, contents, 0, size))
351    return FALSE;
352
353  if (! parse_ieee (dhandle, abfd, contents, size))
354    return FALSE;
355
356  free (contents);
357
358  *pfound = TRUE;
359
360  return TRUE;
361}
362
363/* Record stabs strings, so that we can give some context for errors.  */
364
365#define SAVE_STABS_COUNT (16)
366
367struct saved_stab
368{
369  int type;
370  int desc;
371  bfd_vma value;
372  char *string;
373};
374
375static struct saved_stab saved_stabs[SAVE_STABS_COUNT];
376static int saved_stabs_index;
377
378/* Save a stabs string.  */
379
380static void
381save_stab (int type, int desc, bfd_vma value, const char *string)
382{
383  if (saved_stabs[saved_stabs_index].string != NULL)
384    free (saved_stabs[saved_stabs_index].string);
385  saved_stabs[saved_stabs_index].type = type;
386  saved_stabs[saved_stabs_index].desc = desc;
387  saved_stabs[saved_stabs_index].value = value;
388  saved_stabs[saved_stabs_index].string = xstrdup (string);
389  saved_stabs_index = (saved_stabs_index + 1) % SAVE_STABS_COUNT;
390}
391
392/* Provide context for an error.  */
393
394static void
395stab_context (void)
396{
397  int i;
398
399  fprintf (stderr, _("Last stabs entries before error:\n"));
400  fprintf (stderr, "n_type n_desc n_value  string\n");
401
402  i = saved_stabs_index;
403  do
404    {
405      struct saved_stab *stabp;
406
407      stabp = saved_stabs + i;
408      if (stabp->string != NULL)
409	{
410	  const char *s;
411
412	  s = bfd_get_stab_name (stabp->type);
413	  if (s != NULL)
414	    fprintf (stderr, "%-6s", s);
415	  else if (stabp->type == 0)
416	    fprintf (stderr, "HdrSym");
417	  else
418	    fprintf (stderr, "%-6d", stabp->type);
419	  fprintf (stderr, " %-6d ", stabp->desc);
420	  fprintf_vma (stderr, stabp->value);
421	  if (stabp->type != 0)
422	    fprintf (stderr, " %s", stabp->string);
423	  fprintf (stderr, "\n");
424	}
425      i = (i + 1) % SAVE_STABS_COUNT;
426    }
427  while (i != saved_stabs_index);
428}
429
430/* Free the saved stab strings.  */
431
432static void
433free_saved_stabs (void)
434{
435  int i;
436
437  for (i = 0; i < SAVE_STABS_COUNT; i++)
438    {
439      if (saved_stabs[i].string != NULL)
440	{
441	  free (saved_stabs[i].string);
442	  saved_stabs[i].string = NULL;
443	}
444    }
445
446  saved_stabs_index = 0;
447}
448