1 /* rddbg.c -- Read debugging information into a generic form.
2 Copyright (C) 1995-2016 Free Software Foundation, Inc.
3 Written by Ian Lance Taylor <ian@cygnus.com>.
4
5 This file is part of GNU Binutils.
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
20 02110-1301, USA. */
21
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
34 static bfd_boolean read_section_stabs_debugging_info
35 (bfd *, asymbol **, long, void *, bfd_boolean *);
36 static bfd_boolean read_symbol_stabs_debugging_info
37 (bfd *, asymbol **, long, void *, bfd_boolean *);
38 static bfd_boolean read_ieee_debugging_info (bfd *, void *, bfd_boolean *);
39 static void save_stab (int, int, bfd_vma, const char *);
40 static void stab_context (void);
41 static void free_saved_stabs (void);
42
43 /* Read debugging information from a BFD. Returns a generic debugging
44 pointer. */
45
46 void *
read_debugging_info(bfd * abfd,asymbol ** syms,long symcount,bfd_boolean no_messages)47 read_debugging_info (bfd *abfd, asymbol **syms, long symcount, bfd_boolean no_messages)
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 if (! no_messages)
87 non_fatal (_("%s: no recognized debugging information"),
88 bfd_get_filename (abfd));
89 return NULL;
90 }
91
92 return dhandle;
93 }
94
95 /* Read stabs in sections debugging information from a BFD. */
96
97 static bfd_boolean
read_section_stabs_debugging_info(bfd * abfd,asymbol ** syms,long symcount,void * dhandle,bfd_boolean * pfound)98 read_section_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount,
99 void *dhandle, bfd_boolean *pfound)
100 {
101 static struct
102 {
103 const char *secname;
104 const char *strsecname;
105 }
106 names[] =
107 {
108 { ".stab", ".stabstr" },
109 { "LC_SYMTAB.stabs", "LC_SYMTAB.stabstr" },
110 { "$GDB_SYMBOLS$", "$GDB_STRINGS$" }
111 };
112 unsigned int i;
113 void *shandle;
114
115 *pfound = FALSE;
116 shandle = NULL;
117
118 for (i = 0; i < sizeof names / sizeof names[0]; i++)
119 {
120 asection *sec, *strsec;
121
122 sec = bfd_get_section_by_name (abfd, names[i].secname);
123 strsec = bfd_get_section_by_name (abfd, names[i].strsecname);
124 if (sec != NULL && strsec != NULL)
125 {
126 bfd_size_type stabsize, strsize;
127 bfd_byte *stabs, *strings;
128 bfd_byte *stab;
129 bfd_size_type stroff, next_stroff;
130
131 stabsize = bfd_section_size (abfd, sec);
132 stabs = (bfd_byte *) xmalloc (stabsize);
133 if (! bfd_get_section_contents (abfd, sec, stabs, 0, stabsize))
134 {
135 fprintf (stderr, "%s: %s: %s\n",
136 bfd_get_filename (abfd), names[i].secname,
137 bfd_errmsg (bfd_get_error ()));
138 return FALSE;
139 }
140
141 strsize = bfd_section_size (abfd, strsec);
142 strings = (bfd_byte *) xmalloc (strsize + 1);
143 if (! bfd_get_section_contents (abfd, strsec, strings, 0, strsize))
144 {
145 fprintf (stderr, "%s: %s: %s\n",
146 bfd_get_filename (abfd), names[i].strsecname,
147 bfd_errmsg (bfd_get_error ()));
148 return FALSE;
149 }
150 /* Zero terminate the strings table, just in case. */
151 strings [strsize] = 0;
152 if (shandle == NULL)
153 {
154 shandle = start_stab (dhandle, abfd, TRUE, syms, symcount);
155 if (shandle == NULL)
156 return FALSE;
157 }
158
159 *pfound = TRUE;
160
161 stroff = 0;
162 next_stroff = 0;
163 /* PR 17512: file: 078-60391-0.001:0.1. */
164 for (stab = stabs; stab <= (stabs + stabsize) - 12; stab += 12)
165 {
166 unsigned int strx;
167 int type;
168 int other ATTRIBUTE_UNUSED;
169 int desc;
170 bfd_vma value;
171
172 /* This code presumes 32 bit values. */
173
174 strx = bfd_get_32 (abfd, stab);
175 type = bfd_get_8 (abfd, stab + 4);
176 other = bfd_get_8 (abfd, stab + 5);
177 desc = bfd_get_16 (abfd, stab + 6);
178 value = bfd_get_32 (abfd, stab + 8);
179
180 if (type == 0)
181 {
182 /* Special type 0 stabs indicate the offset to the
183 next string table. */
184 stroff = next_stroff;
185 next_stroff += value;
186 }
187 else
188 {
189 size_t len;
190 char *f, *s;
191
192 if (stroff + strx >= strsize)
193 {
194 fprintf (stderr, _("%s: %s: stab entry %ld is corrupt, strx = 0x%x, type = %d\n"),
195 bfd_get_filename (abfd), names[i].secname,
196 (long) (stab - stabs) / 12, strx, type);
197 continue;
198 }
199
200 s = (char *) strings + stroff + strx;
201 f = NULL;
202
203 /* PR 17512: file: 002-87578-0.001:0.1.
204 It is possible to craft a file where, without the 'strlen (s) > 0',
205 an attempt to read the byte before 'strings' would occur. */
206 while ((len = strlen (s)) > 0
207 && s[len - 1] == '\\'
208 && stab + 12 < stabs + stabsize)
209 {
210 char *p;
211
212 stab += 12;
213 p = s + len - 1;
214 *p = '\0';
215 strx = stroff + bfd_get_32 (abfd, stab);
216 if (strx >= strsize)
217 {
218 fprintf (stderr, _("%s: %s: stab entry %ld is corrupt\n"),
219 bfd_get_filename (abfd), names[i].secname,
220 (long) (stab - stabs) / 12);
221 break;
222 }
223 else
224 s = concat (s, (char *) strings + strx,
225 (const char *) NULL);
226
227 /* We have to restore the backslash, because, if
228 the linker is hashing stabs strings, we may
229 see the same string more than once. */
230 *p = '\\';
231
232 if (f != NULL)
233 free (f);
234 f = s;
235 }
236
237 save_stab (type, desc, value, s);
238
239 if (! parse_stab (dhandle, shandle, type, desc, value, s))
240 {
241 stab_context ();
242 free_saved_stabs ();
243 return FALSE;
244 }
245
246 /* Don't free f, since I think the stabs code
247 expects strings to hang around. This should be
248 straightened out. FIXME. */
249 }
250 }
251
252 free_saved_stabs ();
253 free (stabs);
254
255 /* Don't free strings, since I think the stabs code expects
256 the strings to hang around. This should be straightened
257 out. FIXME. */
258 }
259 }
260
261 if (shandle != NULL)
262 {
263 if (! finish_stab (dhandle, shandle))
264 return FALSE;
265 }
266
267 return TRUE;
268 }
269
270 /* Read stabs in the symbol table. */
271
272 static bfd_boolean
read_symbol_stabs_debugging_info(bfd * abfd,asymbol ** syms,long symcount,void * dhandle,bfd_boolean * pfound)273 read_symbol_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount,
274 void *dhandle, bfd_boolean *pfound)
275 {
276 void *shandle;
277 asymbol **ps, **symend;
278
279 shandle = NULL;
280 symend = syms + symcount;
281 for (ps = syms; ps < symend; ps++)
282 {
283 symbol_info i;
284
285 bfd_get_symbol_info (abfd, *ps, &i);
286
287 if (i.type == '-')
288 {
289 const char *s;
290 char *f;
291
292 if (shandle == NULL)
293 {
294 shandle = start_stab (dhandle, abfd, FALSE, syms, symcount);
295 if (shandle == NULL)
296 return FALSE;
297 }
298
299 *pfound = TRUE;
300
301 s = i.name;
302 f = NULL;
303 while (s[strlen (s) - 1] == '\\'
304 && ps + 1 < symend)
305 {
306 char *sc, *n;
307
308 ++ps;
309 sc = xstrdup (s);
310 sc[strlen (sc) - 1] = '\0';
311 n = concat (sc, bfd_asymbol_name (*ps), (const char *) NULL);
312 free (sc);
313 if (f != NULL)
314 free (f);
315 f = n;
316 s = n;
317 }
318
319 save_stab (i.stab_type, i.stab_desc, i.value, s);
320
321 if (! parse_stab (dhandle, shandle, i.stab_type, i.stab_desc,
322 i.value, s))
323 {
324 stab_context ();
325 free_saved_stabs ();
326 return FALSE;
327 }
328
329 /* Don't free f, since I think the stabs code expects
330 strings to hang around. This should be straightened out.
331 FIXME. */
332 }
333 }
334
335 free_saved_stabs ();
336
337 if (shandle != NULL)
338 {
339 if (! finish_stab (dhandle, shandle))
340 return FALSE;
341 }
342
343 return TRUE;
344 }
345
346 /* Read IEEE debugging information. */
347
348 static bfd_boolean
read_ieee_debugging_info(bfd * abfd,void * dhandle,bfd_boolean * pfound)349 read_ieee_debugging_info (bfd *abfd, void *dhandle, bfd_boolean *pfound)
350 {
351 asection *dsec;
352 bfd_size_type size;
353 bfd_byte *contents;
354
355 /* The BFD backend puts the debugging information into a section
356 named .debug. */
357
358 dsec = bfd_get_section_by_name (abfd, ".debug");
359 if (dsec == NULL)
360 return TRUE;
361
362 size = bfd_section_size (abfd, dsec);
363 contents = (bfd_byte *) xmalloc (size);
364 if (! bfd_get_section_contents (abfd, dsec, contents, 0, size))
365 return FALSE;
366
367 if (! parse_ieee (dhandle, abfd, contents, size))
368 return FALSE;
369
370 free (contents);
371
372 *pfound = TRUE;
373
374 return TRUE;
375 }
376
377 /* Record stabs strings, so that we can give some context for errors. */
378
379 #define SAVE_STABS_COUNT (16)
380
381 struct saved_stab
382 {
383 int type;
384 int desc;
385 bfd_vma value;
386 char *string;
387 };
388
389 static struct saved_stab saved_stabs[SAVE_STABS_COUNT];
390 static int saved_stabs_index;
391
392 /* Save a stabs string. */
393
394 static void
save_stab(int type,int desc,bfd_vma value,const char * string)395 save_stab (int type, int desc, bfd_vma value, const char *string)
396 {
397 if (saved_stabs[saved_stabs_index].string != NULL)
398 free (saved_stabs[saved_stabs_index].string);
399 saved_stabs[saved_stabs_index].type = type;
400 saved_stabs[saved_stabs_index].desc = desc;
401 saved_stabs[saved_stabs_index].value = value;
402 saved_stabs[saved_stabs_index].string = xstrdup (string);
403 saved_stabs_index = (saved_stabs_index + 1) % SAVE_STABS_COUNT;
404 }
405
406 /* Provide context for an error. */
407
408 static void
stab_context(void)409 stab_context (void)
410 {
411 int i;
412
413 fprintf (stderr, _("Last stabs entries before error:\n"));
414 fprintf (stderr, "n_type n_desc n_value string\n");
415
416 i = saved_stabs_index;
417 do
418 {
419 struct saved_stab *stabp;
420
421 stabp = saved_stabs + i;
422 if (stabp->string != NULL)
423 {
424 const char *s;
425
426 s = bfd_get_stab_name (stabp->type);
427 if (s != NULL)
428 fprintf (stderr, "%-6s", s);
429 else if (stabp->type == 0)
430 fprintf (stderr, "HdrSym");
431 else
432 fprintf (stderr, "%-6d", stabp->type);
433 fprintf (stderr, " %-6d ", stabp->desc);
434 fprintf_vma (stderr, stabp->value);
435 if (stabp->type != 0)
436 fprintf (stderr, " %s", stabp->string);
437 fprintf (stderr, "\n");
438 }
439 i = (i + 1) % SAVE_STABS_COUNT;
440 }
441 while (i != saved_stabs_index);
442 }
443
444 /* Free the saved stab strings. */
445
446 static void
free_saved_stabs(void)447 free_saved_stabs (void)
448 {
449 int i;
450
451 for (i = 0; i < SAVE_STABS_COUNT; i++)
452 {
453 if (saved_stabs[i].string != NULL)
454 {
455 free (saved_stabs[i].string);
456 saved_stabs[i].string = NULL;
457 }
458 }
459
460 saved_stabs_index = 0;
461 }
462