binutils/rddbg.c

   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
  33 static bfd_boolean read_section_stabs_debugging_info
  34   (bfd *, asymbol **, long, void *, bfd_boolean *);
  35 static bfd_boolean read_symbol_stabs_debugging_info
  36   (bfd *, asymbol **, long, void *, bfd_boolean *);
  37 static bfd_boolean read_ieee_debugging_info (bfd *, void *, bfd_boolean *);
  38 static void save_stab (int, int, bfd_vma, const char *);
  39 static void stab_context (void);
  40 static void free_saved_stabs (void);
  41
  42 /* Read debugging information from a BFD.  Returns a generic debugging
  43    pointer.  */
  44
  45 void *
  46 read_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
  95 static bfd_boolean
  96 read_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
 258 static bfd_boolean
 259 read_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
 334 static bfd_boolean
 335 read_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 \f
 363 /* Record stabs strings, so that we can give some context for errors.  */
 364
 365 #define SAVE_STABS_COUNT (16)
 366
 367 struct saved_stab
 368 {
 369   int type;
 370   int desc;
 371   bfd_vma value;
 372   char *string;
 373 };
 374
 375 static struct saved_stab saved_stabs[SAVE_STABS_COUNT];
 376 static int saved_stabs_index;
 377
 378 /* Save a stabs string.  */
 379
 380 static void
 381 save_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
 394 static void
 395 stab_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
 432 static void
 433 free_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 }