binutils/rddbg.c

   1 /* rddbg.c -- Read debugging information into a generic form.
   2    Copyright (C) 1995-2014 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 *
  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
  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);
 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
 151           if (shandle == NULL)
 152             {
 153               shandle = start_stab (dhandle, abfd, TRUE, syms, symcount);
 154               if (shandle == NULL)
 155                 return FALSE;
 156             }
 157
 158           *pfound = TRUE;
 159
 160           stroff = 0;
 161           next_stroff = 0;
 162           for (stab = stabs; stab < stabs + stabsize; stab += 12)
 163             {
 164               unsigned int strx;
 165               int type;
 166               int other ATTRIBUTE_UNUSED;
 167               int desc;
 168               bfd_vma value;
 169
 170               /* This code presumes 32 bit values.  */
 171
 172               strx = bfd_get_32 (abfd, stab);
 173               type = bfd_get_8 (abfd, stab + 4);
 174               other = bfd_get_8 (abfd, stab + 5);
 175               desc = bfd_get_16 (abfd, stab + 6);
 176               value = bfd_get_32 (abfd, stab + 8);
 177
 178               if (type == 0)
 179                 {
 180                   /* Special type 0 stabs indicate the offset to the
 181                      next string table.  */
 182                   stroff = next_stroff;
 183                   next_stroff += value;
 184                 }
 185               else
 186                 {
 187                   char *f, *s;
 188
 189                   f = NULL;
 190
 191                   if (stroff + strx > strsize)
 192                     {
 193                       fprintf (stderr, "%s: %s: stab entry %ld is corrupt, strx = 0x%x, type = %d\n",
 194                                bfd_get_filename (abfd), names[i].secname,
 195                                (long) (stab - stabs) / 12, strx, type);
 196                       continue;
 197                     }
 198
 199                   s = (char *) strings + stroff + strx;
 200
 201                   while (s[strlen (s) - 1] == '\\'
 202                          && stab + 12 < stabs + stabsize)
 203                     {
 204                       char *p;
 205
 206                       stab += 12;
 207                       p = s + strlen (s) - 1;
 208                       *p = '\0';
 209                       s = concat (s,
 210                                   ((char *) strings
 211                                    + stroff
 212                                    + bfd_get_32 (abfd, stab)),
 213                                   (const char *) NULL);
 214
 215                       /* We have to restore the backslash, because, if
 216                          the linker is hashing stabs strings, we may
 217                          see the same string more than once.  */
 218                       *p = '\\';
 219
 220                       if (f != NULL)
 221                         free (f);
 222                       f = s;
 223                     }
 224
 225                   save_stab (type, desc, value, s);
 226
 227                   if (! parse_stab (dhandle, shandle, type, desc, value, s))
 228                     {
 229                       stab_context ();
 230                       free_saved_stabs ();
 231                       return FALSE;
 232                     }
 233
 234                   /* Don't free f, since I think the stabs code
 235                      expects strings to hang around.  This should be
 236                      straightened out.  FIXME.  */
 237                 }
 238             }
 239
 240           free_saved_stabs ();
 241           free (stabs);
 242
 243           /* Don't free strings, since I think the stabs code expects
 244              the strings to hang around.  This should be straightened
 245              out.  FIXME.  */
 246         }
 247     }
 248
 249   if (shandle != NULL)
 250     {
 251       if (! finish_stab (dhandle, shandle))
 252         return FALSE;
 253     }
 254
 255   return TRUE;
 256 }
 257
 258 /* Read stabs in the symbol table.  */
 259
 260 static bfd_boolean
 261 read_symbol_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount,
 262                                   void *dhandle, bfd_boolean *pfound)
 263 {
 264   void *shandle;
 265   asymbol **ps, **symend;
 266
 267   shandle = NULL;
 268   symend = syms + symcount;
 269   for (ps = syms; ps < symend; ps++)
 270     {
 271       symbol_info i;
 272
 273       bfd_get_symbol_info (abfd, *ps, &i);
 274
 275       if (i.type == '-')
 276         {
 277           const char *s;
 278           char *f;
 279
 280           if (shandle == NULL)
 281             {
 282               shandle = start_stab (dhandle, abfd, FALSE, syms, symcount);
 283               if (shandle == NULL)
 284                 return FALSE;
 285             }
 286
 287           *pfound = TRUE;
 288
 289           s = i.name;
 290           f = NULL;
 291           while (s[strlen (s) - 1] == '\\'
 292                  && ps + 1 < symend)
 293             {
 294               char *sc, *n;
 295
 296               ++ps;
 297               sc = xstrdup (s);
 298               sc[strlen (sc) - 1] = '\0';
 299               n = concat (sc, bfd_asymbol_name (*ps), (const char *) NULL);
 300               free (sc);
 301               if (f != NULL)
 302                 free (f);
 303               f = n;
 304               s = n;
 305             }
 306
 307           save_stab (i.stab_type, i.stab_desc, i.value, s);
 308
 309           if (! parse_stab (dhandle, shandle, i.stab_type, i.stab_desc,
 310                             i.value, s))
 311             {
 312               stab_context ();
 313               free_saved_stabs ();
 314               return FALSE;
 315             }
 316
 317           /* Don't free f, since I think the stabs code expects
 318              strings to hang around.  This should be straightened out.
 319              FIXME.  */
 320         }
 321     }
 322
 323   free_saved_stabs ();
 324
 325   if (shandle != NULL)
 326     {
 327       if (! finish_stab (dhandle, shandle))
 328         return FALSE;
 329     }
 330
 331   return TRUE;
 332 }
 333
 334 /* Read IEEE debugging information.  */
 335
 336 static bfd_boolean
 337 read_ieee_debugging_info (bfd *abfd, void *dhandle, bfd_boolean *pfound)
 338 {
 339   asection *dsec;
 340   bfd_size_type size;
 341   bfd_byte *contents;
 342
 343   /* The BFD backend puts the debugging information into a section
 344      named .debug.  */
 345
 346   dsec = bfd_get_section_by_name (abfd, ".debug");
 347   if (dsec == NULL)
 348     return TRUE;
 349
 350   size = bfd_section_size (abfd, dsec);
 351   contents = (bfd_byte *) xmalloc (size);
 352   if (! bfd_get_section_contents (abfd, dsec, contents, 0, size))
 353     return FALSE;
 354
 355   if (! parse_ieee (dhandle, abfd, contents, size))
 356     return FALSE;
 357
 358   free (contents);
 359
 360   *pfound = TRUE;
 361
 362   return TRUE;
 363 }
 364 \f
 365 /* Record stabs strings, so that we can give some context for errors.  */
 366
 367 #define SAVE_STABS_COUNT (16)
 368
 369 struct saved_stab
 370 {
 371   int type;
 372   int desc;
 373   bfd_vma value;
 374   char *string;
 375 };
 376
 377 static struct saved_stab saved_stabs[SAVE_STABS_COUNT];
 378 static int saved_stabs_index;
 379
 380 /* Save a stabs string.  */
 381
 382 static void
 383 save_stab (int type, int desc, bfd_vma value, const char *string)
 384 {
 385   if (saved_stabs[saved_stabs_index].string != NULL)
 386     free (saved_stabs[saved_stabs_index].string);
 387   saved_stabs[saved_stabs_index].type = type;
 388   saved_stabs[saved_stabs_index].desc = desc;
 389   saved_stabs[saved_stabs_index].value = value;
 390   saved_stabs[saved_stabs_index].string = xstrdup (string);
 391   saved_stabs_index = (saved_stabs_index + 1) % SAVE_STABS_COUNT;
 392 }
 393
 394 /* Provide context for an error.  */
 395
 396 static void
 397 stab_context (void)
 398 {
 399   int i;
 400
 401   fprintf (stderr, _("Last stabs entries before error:\n"));
 402   fprintf (stderr, "n_type n_desc n_value  string\n");
 403
 404   i = saved_stabs_index;
 405   do
 406     {
 407       struct saved_stab *stabp;
 408
 409       stabp = saved_stabs + i;
 410       if (stabp->string != NULL)
 411         {
 412           const char *s;
 413
 414           s = bfd_get_stab_name (stabp->type);
 415           if (s != NULL)
 416             fprintf (stderr, "%-6s", s);
 417           else if (stabp->type == 0)
 418             fprintf (stderr, "HdrSym");
 419           else
 420             fprintf (stderr, "%-6d", stabp->type);
 421           fprintf (stderr, " %-6d ", stabp->desc);
 422           fprintf_vma (stderr, stabp->value);
 423           if (stabp->type != 0)
 424             fprintf (stderr, " %s", stabp->string);
 425           fprintf (stderr, "\n");
 426         }
 427       i = (i + 1) % SAVE_STABS_COUNT;
 428     }
 429   while (i != saved_stabs_index);
 430 }
 431
 432 /* Free the saved stab strings.  */
 433
 434 static void
 435 free_saved_stabs (void)
 436 {
 437   int i;
 438
 439   for (i = 0; i < SAVE_STABS_COUNT; i++)
 440     {
 441       if (saved_stabs[i].string != NULL)
 442         {
 443           free (saved_stabs[i].string);
 444           saved_stabs[i].string = NULL;
 445         }
 446     }
 447
 448   saved_stabs_index = 0;
 449 }