binutils/rddbg.c

   1 /* rddbg.c -- Read debugging information into a generic form.
   2    Copyright 1995, 1996, 1997, 2000, 2002, 2003, 2005, 2007, 2008,
   3    2010  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 3 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
  24 /* This file reads debugging information into a generic form.  This
  25    file knows how to dig the debugging information out of an object
  26    file.  */
  27
  28 #include "sysdep.h"
  29 #include "bfd.h"
  30 #include "libiberty.h"
  31 #include "bucomm.h"
  32 #include "debug.h"
  33 #include "budbg.h"
  34
  35 static bfd_boolean read_section_stabs_debugging_info
  36   (bfd *, asymbol **, long, void *, bfd_boolean *);
  37 static bfd_boolean read_symbol_stabs_debugging_info
  38   (bfd *, asymbol **, long, void *, bfd_boolean *);
  39 static bfd_boolean read_ieee_debugging_info (bfd *, void *, bfd_boolean *);
  40 static void save_stab (int, int, bfd_vma, const char *);
  41 static void stab_context (void);
  42 static void free_saved_stabs (void);
  43
  44 /* Read debugging information from a BFD.  Returns a generic debugging
  45    pointer.  */
  46
  47 void *
  48 read_debugging_info (bfd *abfd, asymbol **syms, long symcount, bfd_boolean no_messages)
  49 {
  50   void *dhandle;
  51   bfd_boolean found;
  52
  53   dhandle = debug_init ();
  54   if (dhandle == NULL)
  55     return NULL;
  56
  57   if (! read_section_stabs_debugging_info (abfd, syms, symcount, dhandle,
  58                                            &found))
  59     return NULL;
  60
  61   if (bfd_get_flavour (abfd) == bfd_target_aout_flavour)
  62     {
  63       if (! read_symbol_stabs_debugging_info (abfd, syms, symcount, dhandle,
  64                                               &found))
  65         return NULL;
  66     }
  67
  68   if (bfd_get_flavour (abfd) == bfd_target_ieee_flavour)
  69     {
  70       if (! read_ieee_debugging_info (abfd, dhandle, &found))
  71         return NULL;
  72     }
  73
  74   /* Try reading the COFF symbols if we didn't find any stabs in COFF
  75      sections.  */
  76   if (! found
  77       && bfd_get_flavour (abfd) == bfd_target_coff_flavour
  78       && symcount > 0)
  79     {
  80       if (! parse_coff (abfd, syms, symcount, dhandle))
  81         return NULL;
  82       found = TRUE;
  83     }
  84
  85   if (! found)
  86     {
  87       if (! no_messages)
  88         non_fatal (_("%s: no recognized debugging information"),
  89                    bfd_get_filename (abfd));
  90       return NULL;
  91     }
  92
  93   return dhandle;
  94 }
  95
  96 /* Read stabs in sections debugging information from a BFD.  */
  97
  98 static bfd_boolean
  99 read_section_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount,
 100                                    void *dhandle, bfd_boolean *pfound)
 101 {
 102   static struct
 103     {
 104       const char *secname;
 105       const char *strsecname;
 106     }
 107   names[] =
 108     {
 109       { ".stab", ".stabstr" },
 110       { "LC_SYMTAB.stabs", "LC_SYMTAB.stabstr" },
 111       { "$GDB_SYMBOLS$", "$GDB_STRINGS$" }
 112     };
 113   unsigned int i;
 114   void *shandle;
 115
 116   *pfound = FALSE;
 117   shandle = NULL;
 118
 119   for (i = 0; i < sizeof names / sizeof names[0]; i++)
 120     {
 121       asection *sec, *strsec;
 122
 123       sec = bfd_get_section_by_name (abfd, names[i].secname);
 124       strsec = bfd_get_section_by_name (abfd, names[i].strsecname);
 125       if (sec != NULL && strsec != NULL)
 126         {
 127           bfd_size_type stabsize, strsize;
 128           bfd_byte *stabs, *strings;
 129           bfd_byte *stab;
 130           bfd_size_type stroff, next_stroff;
 131
 132           stabsize = bfd_section_size (abfd, sec);
 133           stabs = (bfd_byte *) xmalloc (stabsize);
 134           if (! bfd_get_section_contents (abfd, sec, stabs, 0, stabsize))
 135             {
 136               fprintf (stderr, "%s: %s: %s\n",
 137                        bfd_get_filename (abfd), names[i].secname,
 138                        bfd_errmsg (bfd_get_error ()));
 139               return FALSE;
 140             }
 141
 142           strsize = bfd_section_size (abfd, strsec);
 143           strings = (bfd_byte *) xmalloc (strsize);
 144           if (! bfd_get_section_contents (abfd, strsec, strings, 0, strsize))
 145             {
 146               fprintf (stderr, "%s: %s: %s\n",
 147                        bfd_get_filename (abfd), names[i].strsecname,
 148                        bfd_errmsg (bfd_get_error ()));
 149               return FALSE;
 150             }
 151
 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           for (stab = stabs; stab < stabs + stabsize; stab += 12)
 164             {
 165               unsigned int strx;
 166               int type;
 167               int other ATTRIBUTE_UNUSED;
 168               int desc;
 169               bfd_vma value;
 170
 171               /* This code presumes 32 bit values.  */
 172
 173               strx = bfd_get_32 (abfd, stab);
 174               type = bfd_get_8 (abfd, stab + 4);
 175               other = bfd_get_8 (abfd, stab + 5);
 176               desc = bfd_get_16 (abfd, stab + 6);
 177               value = bfd_get_32 (abfd, stab + 8);
 178
 179               if (type == 0)
 180                 {
 181                   /* Special type 0 stabs indicate the offset to the
 182                      next string table.  */
 183                   stroff = next_stroff;
 184                   next_stroff += value;
 185                 }
 186               else
 187                 {
 188                   char *f, *s;
 189
 190                   f = NULL;
 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
 202                   while (s[strlen (s) - 1] == '\\'
 203                          && stab + 12 < stabs + stabsize)
 204                     {
 205                       char *p;
 206
 207                       stab += 12;
 208                       p = s + strlen (s) - 1;
 209                       *p = '\0';
 210                       s = concat (s,
 211                                   ((char *) strings
 212                                    + stroff
 213                                    + bfd_get_32 (abfd, stab)),
 214                                   (const char *) NULL);
 215
 216                       /* We have to restore the backslash, because, if
 217                          the linker is hashing stabs strings, we may
 218                          see the same string more than once.  */
 219                       *p = '\\';
 220
 221                       if (f != NULL)
 222                         free (f);
 223                       f = s;
 224                     }
 225
 226                   save_stab (type, desc, value, s);
 227
 228                   if (! parse_stab (dhandle, shandle, type, desc, value, s))
 229                     {
 230                       stab_context ();
 231                       free_saved_stabs ();
 232                       return FALSE;
 233                     }
 234
 235                   /* Don't free f, since I think the stabs code
 236                      expects strings to hang around.  This should be
 237                      straightened out.  FIXME.  */
 238                 }
 239             }
 240
 241           free_saved_stabs ();
 242           free (stabs);
 243
 244           /* Don't free strings, since I think the stabs code expects
 245              the strings to hang around.  This should be straightened
 246              out.  FIXME.  */
 247         }
 248     }
 249
 250   if (shandle != NULL)
 251     {
 252       if (! finish_stab (dhandle, shandle))
 253         return FALSE;
 254     }
 255
 256   return TRUE;
 257 }
 258
 259 /* Read stabs in the symbol table.  */
 260
 261 static bfd_boolean
 262 read_symbol_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount,
 263                                   void *dhandle, bfd_boolean *pfound)
 264 {
 265   void *shandle;
 266   asymbol **ps, **symend;
 267
 268   shandle = NULL;
 269   symend = syms + symcount;
 270   for (ps = syms; ps < symend; ps++)
 271     {
 272       symbol_info i;
 273
 274       bfd_get_symbol_info (abfd, *ps, &i);
 275
 276       if (i.type == '-')
 277         {
 278           const char *s;
 279           char *f;
 280
 281           if (shandle == NULL)
 282             {
 283               shandle = start_stab (dhandle, abfd, FALSE, syms, symcount);
 284               if (shandle == NULL)
 285                 return FALSE;
 286             }
 287
 288           *pfound = TRUE;
 289
 290           s = i.name;
 291           f = NULL;
 292           while (s[strlen (s) - 1] == '\\'
 293                  && ps + 1 < symend)
 294             {
 295               char *sc, *n;
 296
 297               ++ps;
 298               sc = xstrdup (s);
 299               sc[strlen (sc) - 1] = '\0';
 300               n = concat (sc, bfd_asymbol_name (*ps), (const char *) NULL);
 301               free (sc);
 302               if (f != NULL)
 303                 free (f);
 304               f = n;
 305               s = n;
 306             }
 307
 308           save_stab (i.stab_type, i.stab_desc, i.value, s);
 309
 310           if (! parse_stab (dhandle, shandle, i.stab_type, i.stab_desc,
 311                             i.value, s))
 312             {
 313               stab_context ();
 314               free_saved_stabs ();
 315               return FALSE;
 316             }
 317
 318           /* Don't free f, since I think the stabs code expects
 319              strings to hang around.  This should be straightened out.
 320              FIXME.  */
 321         }
 322     }
 323
 324   free_saved_stabs ();
 325
 326   if (shandle != NULL)
 327     {
 328       if (! finish_stab (dhandle, shandle))
 329         return FALSE;
 330     }
 331
 332   return TRUE;
 333 }
 334
 335 /* Read IEEE debugging information.  */
 336
 337 static bfd_boolean
 338 read_ieee_debugging_info (bfd *abfd, void *dhandle, bfd_boolean *pfound)
 339 {
 340   asection *dsec;
 341   bfd_size_type size;
 342   bfd_byte *contents;
 343
 344   /* The BFD backend puts the debugging information into a section
 345      named .debug.  */
 346
 347   dsec = bfd_get_section_by_name (abfd, ".debug");
 348   if (dsec == NULL)
 349     return TRUE;
 350
 351   size = bfd_section_size (abfd, dsec);
 352   contents = (bfd_byte *) xmalloc (size);
 353   if (! bfd_get_section_contents (abfd, dsec, contents, 0, size))
 354     return FALSE;
 355
 356   if (! parse_ieee (dhandle, abfd, contents, size))
 357     return FALSE;
 358
 359   free (contents);
 360
 361   *pfound = TRUE;
 362
 363   return TRUE;
 364 }
 365 \f
 366 /* Record stabs strings, so that we can give some context for errors.  */
 367
 368 #define SAVE_STABS_COUNT (16)
 369
 370 struct saved_stab
 371 {
 372   int type;
 373   int desc;
 374   bfd_vma value;
 375   char *string;
 376 };
 377
 378 static struct saved_stab saved_stabs[SAVE_STABS_COUNT];
 379 static int saved_stabs_index;
 380
 381 /* Save a stabs string.  */
 382
 383 static void
 384 save_stab (int type, int desc, bfd_vma value, const char *string)
 385 {
 386   if (saved_stabs[saved_stabs_index].string != NULL)
 387     free (saved_stabs[saved_stabs_index].string);
 388   saved_stabs[saved_stabs_index].type = type;
 389   saved_stabs[saved_stabs_index].desc = desc;
 390   saved_stabs[saved_stabs_index].value = value;
 391   saved_stabs[saved_stabs_index].string = xstrdup (string);
 392   saved_stabs_index = (saved_stabs_index + 1) % SAVE_STABS_COUNT;
 393 }
 394
 395 /* Provide context for an error.  */
 396
 397 static void
 398 stab_context (void)
 399 {
 400   int i;
 401
 402   fprintf (stderr, _("Last stabs entries before error:\n"));
 403   fprintf (stderr, "n_type n_desc n_value  string\n");
 404
 405   i = saved_stabs_index;
 406   do
 407     {
 408       struct saved_stab *stabp;
 409
 410       stabp = saved_stabs + i;
 411       if (stabp->string != NULL)
 412         {
 413           const char *s;
 414
 415           s = bfd_get_stab_name (stabp->type);
 416           if (s != NULL)
 417             fprintf (stderr, "%-6s", s);
 418           else if (stabp->type == 0)
 419             fprintf (stderr, "HdrSym");
 420           else
 421             fprintf (stderr, "%-6d", stabp->type);
 422           fprintf (stderr, " %-6d ", stabp->desc);
 423           fprintf_vma (stderr, stabp->value);
 424           if (stabp->type != 0)
 425             fprintf (stderr, " %s", stabp->string);
 426           fprintf (stderr, "\n");
 427         }
 428       i = (i + 1) % SAVE_STABS_COUNT;
 429     }
 430   while (i != saved_stabs_index);
 431 }
 432
 433 /* Free the saved stab strings.  */
 434
 435 static void
 436 free_saved_stabs (void)
 437 {
 438   int i;
 439
 440   for (i = 0; i < SAVE_STABS_COUNT; i++)
 441     {
 442       if (saved_stabs[i].string != NULL)
 443         {
 444           free (saved_stabs[i].string);
 445           saved_stabs[i].string = NULL;
 446         }
 447     }
 448
 449   saved_stabs_index = 0;
 450 }