rddbg.c revision 302408 
1/* rddbg.c -- Read debugging information into a generic form.
2   Copyright 1995, 1996, 1997, 2000, 2002, 2003, 2005, 2007
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 "sysdep.h"
28#include "bfd.h"
29#include "libiberty.h"
30#include "bucomm.h"
31#include "debug.h"
32#include "budbg.h"
33
34static bfd_boolean read_section_stabs_debugging_info
35  (bfd *, asymbol **, long, void *, bfd_boolean *);
36static bfd_boolean read_symbol_stabs_debugging_info
37  (bfd *, asymbol **, long, void *, bfd_boolean *);
38static bfd_boolean read_ieee_debugging_info (bfd *, void *, bfd_boolean *);
39static void save_stab (int, int, bfd_vma, const char *);
40static void stab_context (void);
41static void free_saved_stabs (void);
42
43/* Read debugging information from a BFD.  Returns a generic debugging
44   pointer.  */
45
46void *
47read_debugging_info (bfd *abfd, asymbol **syms, long symcount)
48{
49  void *dhandle;
50  bfd_boolean found;
51
52  dhandle = debug_init ();
53  if (dhandle == NULL)
54    return NULL;
55
56  if (! read_section_stabs_debugging_info (abfd, syms, symcount, dhandle,
57					   &found))
58    return NULL;
59
60  if (bfd_get_flavour (abfd) == bfd_target_aout_flavour)
61    {
62      if (! read_symbol_stabs_debugging_info (abfd, syms, symcount, dhandle,
63					      &found))
64	return NULL;
65    }
66
67  if (bfd_get_flavour (abfd) == bfd_target_ieee_flavour)
68    {
69      if (! read_ieee_debugging_info (abfd, dhandle, &found))
70	return NULL;
71    }
72
73  /* Try reading the COFF symbols if we didn't find any stabs in COFF
74     sections.  */
75  if (! found
76      && bfd_get_flavour (abfd) == bfd_target_coff_flavour
77      && symcount > 0)
78    {
79      if (! parse_coff (abfd, syms, symcount, dhandle))
80	return NULL;
81      found = TRUE;
82    }
83
84  if (! found)
85    {
86      non_fatal (_("%s: no recognized debugging information"),
87		 bfd_get_filename (abfd));
88      return NULL;
89    }
90
91  return dhandle;
92}
93
94/* Read stabs in sections debugging information from a BFD.  */
95
96static bfd_boolean
97read_section_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount,
98				   void *dhandle, bfd_boolean *pfound)
99{
100  static struct
101    {
102      const char *secname;
103      const char *strsecname;
104    }
105  names[] =
106    {
107      { ".stab", ".stabstr" },
108      { "LC_SYMTAB.stabs", "LC_SYMTAB.stabstr" },
109      { "$GDB_SYMBOLS$", "$GDB_STRINGS$" }
110    };
111  unsigned int i;
112  void *shandle;
113
114  *pfound = FALSE;
115  shandle = NULL;
116
117  for (i = 0; i < sizeof names / sizeof names[0]; i++)
118    {
119      asection *sec, *strsec;
120
121      sec = bfd_get_section_by_name (abfd, names[i].secname);
122      strsec = bfd_get_section_by_name (abfd, names[i].strsecname);
123      if (sec != NULL && strsec != NULL)
124	{
125	  bfd_size_type stabsize, strsize;
126	  bfd_byte *stabs, *strings;
127	  bfd_byte *stab;
128	  bfd_size_type stroff, next_stroff;
129
130	  stabsize = bfd_section_size (abfd, sec);
131	  stabs = (bfd_byte *) xmalloc (stabsize);
132	  if (! bfd_get_section_contents (abfd, sec, stabs, 0, stabsize))
133	    {
134	      fprintf (stderr, "%s: %s: %s\n",
135		       bfd_get_filename (abfd), names[i].secname,
136		       bfd_errmsg (bfd_get_error ()));
137	      return FALSE;
138	    }
139
140	  strsize = bfd_section_size (abfd, strsec);
141	  strings = (bfd_byte *) xmalloc (strsize);
142	  if (! bfd_get_section_contents (abfd, strsec, strings, 0, strsize))
143	    {
144	      fprintf (stderr, "%s: %s: %s\n",
145		       bfd_get_filename (abfd), names[i].strsecname,
146		       bfd_errmsg (bfd_get_error ()));
147	      return FALSE;
148	    }
149
150	  if (shandle == NULL)
151	    {
152	      shandle = start_stab (dhandle, abfd, TRUE, syms, symcount);
153	      if (shandle == NULL)
154		return FALSE;
155	    }
156
157	  *pfound = TRUE;
158
159	  stroff = 0;
160	  next_stroff = 0;
161	  for (stab = stabs; stab < stabs + stabsize; stab += 12)
162	    {
163	      unsigned int strx;
164	      int type;
165	      int other;
166	      int desc;
167	      bfd_vma value;
168
169	      /* This code presumes 32 bit values.  */
170
171	      strx = bfd_get_32 (abfd, stab);
172	      type = bfd_get_8 (abfd, stab + 4);
173	      other = bfd_get_8 (abfd, stab + 5);
174	      desc = bfd_get_16 (abfd, stab + 6);
175	      value = bfd_get_32 (abfd, stab + 8);
176
177	      if (type == 0)
178		{
179		  /* Special type 0 stabs indicate the offset to the
180		     next string table.  */
181		  stroff = next_stroff;
182		  next_stroff += value;
183		}
184	      else
185		{
186		  char *f, *s;
187
188		  f = NULL;
189
190		  if (stroff + strx > strsize)
191		    {
192		      fprintf (stderr, "%s: %s: stab entry %ld is corrupt, strx = 0x%x, type = %d\n",
193			       bfd_get_filename (abfd), names[i].secname,
194			       (long) (stab - stabs) / 12, strx, type);
195		      continue;
196		    }
197
198		  s = (char *) strings + stroff + strx;
199
200		  while (s[strlen (s) - 1] == '\\'
201			 && stab + 12 < stabs + stabsize)
202		    {
203		      char *p;
204
205		      stab += 12;
206		      p = s + strlen (s) - 1;
207		      *p = '\0';
208		      s = concat (s,
209				  ((char *) strings
210				   + stroff
211				   + bfd_get_32 (abfd, stab)),
212				  (const char *) NULL);
213
214		      /* We have to restore the backslash, because, if
215			 the linker is hashing stabs strings, we may
216			 see the same string more than once.  */
217		      *p = '\\';
218
219		      if (f != NULL)
220			free (f);
221		      f = s;
222		    }
223
224		  save_stab (type, desc, value, s);
225
226		  if (! parse_stab (dhandle, shandle, type, desc, value, s))
227		    {
228		      stab_context ();
229		      free_saved_stabs ();
230		      return FALSE;
231		    }
232
233		  /* Don't free f, since I think the stabs code
234		     expects strings to hang around.  This should be
235		     straightened out.  FIXME.  */
236		}
237	    }
238
239	  free_saved_stabs ();
240	  free (stabs);
241
242	  /* Don't free strings, since I think the stabs code expects
243	     the strings to hang around.  This should be straightened
244	     out.  FIXME.  */
245	}
246    }
247
248  if (shandle != NULL)
249    {
250      if (! finish_stab (dhandle, shandle))
251	return FALSE;
252    }
253
254  return TRUE;
255}
256
257/* Read stabs in the symbol table.  */
258
259static bfd_boolean
260read_symbol_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount,
261				  void *dhandle, bfd_boolean *pfound)
262{
263  void *shandle;
264  asymbol **ps, **symend;
265
266  shandle = NULL;
267  symend = syms + symcount;
268  for (ps = syms; ps < symend; ps++)
269    {
270      symbol_info i;
271
272      bfd_get_symbol_info (abfd, *ps, &i);
273
274      if (i.type == '-')
275	{
276	  const char *s;
277	  char *f;
278
279	  if (shandle == NULL)
280	    {
281	      shandle = start_stab (dhandle, abfd, FALSE, syms, symcount);
282	      if (shandle == NULL)
283		return FALSE;
284	    }
285
286	  *pfound = TRUE;
287
288	  s = i.name;
289	  f = NULL;
290	  while (s[strlen (s) - 1] == '\\'
291		 && ps + 1 < symend)
292	    {
293	      char *sc, *n;
294
295	      ++ps;
296	      sc = xstrdup (s);
297	      sc[strlen (sc) - 1] = '\0';
298	      n = concat (sc, bfd_asymbol_name (*ps), (const char *) NULL);
299	      free (sc);
300	      if (f != NULL)
301		free (f);
302	      f = n;
303	      s = n;
304	    }
305
306	  save_stab (i.stab_type, i.stab_desc, i.value, s);
307
308	  if (! parse_stab (dhandle, shandle, i.stab_type, i.stab_desc,
309			    i.value, s))
310	    {
311	      stab_context ();
312	      free_saved_stabs ();
313	      return FALSE;
314	    }
315
316	  /* Don't free f, since I think the stabs code expects
317	     strings to hang around.  This should be straightened out.
318	     FIXME.  */
319	}
320    }
321
322  free_saved_stabs ();
323
324  if (shandle != NULL)
325    {
326      if (! finish_stab (dhandle, shandle))
327	return FALSE;
328    }
329
330  return TRUE;
331}
332
333/* Read IEEE debugging information.  */
334
335static bfd_boolean
336read_ieee_debugging_info (bfd *abfd, void *dhandle, bfd_boolean *pfound)
337{
338  asection *dsec;
339  bfd_size_type size;
340  bfd_byte *contents;
341
342  /* The BFD backend puts the debugging information into a section
343     named .debug.  */
344
345  dsec = bfd_get_section_by_name (abfd, ".debug");
346  if (dsec == NULL)
347    return TRUE;
348
349  size = bfd_section_size (abfd, dsec);
350  contents = (bfd_byte *) xmalloc (size);
351  if (! bfd_get_section_contents (abfd, dsec, contents, 0, size))
352    return FALSE;
353
354  if (! parse_ieee (dhandle, abfd, contents, size))
355    return FALSE;
356
357  free (contents);
358
359  *pfound = TRUE;
360
361  return TRUE;
362}
363
364/* Record stabs strings, so that we can give some context for errors.  */
365
366#define SAVE_STABS_COUNT (16)
367
368struct saved_stab
369{
370  int type;
371  int desc;
372  bfd_vma value;
373  char *string;
374};
375
376static struct saved_stab saved_stabs[SAVE_STABS_COUNT];
377static int saved_stabs_index;
378
379/* Save a stabs string.  */
380
381static void
382save_stab (int type, int desc, bfd_vma value, const char *string)
383{
384  if (saved_stabs[saved_stabs_index].string != NULL)
385    free (saved_stabs[saved_stabs_index].string);
386  saved_stabs[saved_stabs_index].type = type;
387  saved_stabs[saved_stabs_index].desc = desc;
388  saved_stabs[saved_stabs_index].value = value;
389  saved_stabs[saved_stabs_index].string = xstrdup (string);
390  saved_stabs_index = (saved_stabs_index + 1) % SAVE_STABS_COUNT;
391}
392
393/* Provide context for an error.  */
394
395static void
396stab_context (void)
397{
398  int i;
399
400  fprintf (stderr, _("Last stabs entries before error:\n"));
401  fprintf (stderr, "n_type n_desc n_value  string\n");
402
403  i = saved_stabs_index;
404  do
405    {
406      struct saved_stab *stabp;
407
408      stabp = saved_stabs + i;
409      if (stabp->string != NULL)
410	{
411	  const char *s;
412
413	  s = bfd_get_stab_name (stabp->type);
414	  if (s != NULL)
415	    fprintf (stderr, "%-6s", s);
416	  else if (stabp->type == 0)
417	    fprintf (stderr, "HdrSym");
418	  else
419	    fprintf (stderr, "%-6d", stabp->type);
420	  fprintf (stderr, " %-6d ", stabp->desc);
421	  fprintf_vma (stderr, stabp->value);
422	  if (stabp->type != 0)
423	    fprintf (stderr, " %s", stabp->string);
424	  fprintf (stderr, "\n");
425	}
426      i = (i + 1) % SAVE_STABS_COUNT;
427    }
428  while (i != saved_stabs_index);
429}
430
431/* Free the saved stab strings.  */
432
433static void
434free_saved_stabs (void)
435{
436  int i;
437
438  for (i = 0; i < SAVE_STABS_COUNT; i++)
439    {
440      if (saved_stabs[i].string != NULL)
441	{
442	  free (saved_stabs[i].string);
443	  saved_stabs[i].string = NULL;
444	}
445    }
446
447  saved_stabs_index = 0;
448}
449