binutils/rddbg.c

   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
  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 *
  47 read_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
  96 static bfd_boolean
  97 read_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
 259 static bfd_boolean
 260 read_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
 335 static bfd_boolean
 336 read_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 \f
 364 /* Record stabs strings, so that we can give some context for errors.  */
 365
 366 #define SAVE_STABS_COUNT (16)
 367
 368 struct saved_stab
 369 {
 370   int type;
 371   int desc;
 372   bfd_vma value;
 373   char *string;
 374 };
 375
 376 static struct saved_stab saved_stabs[SAVE_STABS_COUNT];
 377 static int saved_stabs_index;
 378
 379 /* Save a stabs string.  */
 380
 381 static void
 382 save_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
 395 static void
 396 stab_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
 433 static void
 434 free_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 }