bfd/dwarf1.c

   1 /* DWARF 1 find nearest line (_bfd_dwarf1_find_nearest_line).
   2    Copyright 1998, 1999, 2000, 2001, 2002, 2004, 2005
   3    Free Software Foundation, Inc.
   4
   5    Written by Gavin Romig-Koch of Cygnus Solutions (gavin@cygnus.com).
   6
   7    This file is part of BFD.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 2 of the License, or (at
  12    your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful, but
  15    WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17    General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program; if not, write to the Free Software
  21    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */
  22
  23 #include "bfd.h"
  24 #include "sysdep.h"
  25 #include "libiberty.h"
  26 #include "libbfd.h"
  27 #include "elf-bfd.h"
  28 #include "elf/dwarf.h"
  29
  30 /* dwarf1_debug is the starting point for all dwarf1 info.  */
  31
  32 struct dwarf1_debug
  33 {
  34   /* The bfd we are working with.  */
  35   bfd* abfd;
  36
  37   /* List of already parsed compilation units.  */
  38   struct dwarf1_unit* lastUnit;
  39
  40   /* The buffer for the .debug section.
  41      Zero indicates that the .debug section failed to load.  */
  42   char* debug_section;
  43
  44   /* Pointer to the end of the .debug_info section memory buffer.  */
  45   char* debug_section_end;
  46
  47   /* The buffer for the .line section.  */
  48   char* line_section;
  49
  50   /* End of that buffer.  */
  51   char* line_section_end;
  52
  53   /* The current or next unread die within the .debug section.  */
  54   char* currentDie;
  55 };
  56
  57 /* One dwarf1_unit for each parsed compilation unit die.  */
  58
  59 struct dwarf1_unit
  60 {
  61   /* Linked starting from stash->lastUnit.  */
  62   struct dwarf1_unit* prev;
  63
  64   /* Name of the compilation unit.  */
  65   char* name;
  66
  67   /* The highest and lowest address used in the compilation unit.  */
  68   unsigned long low_pc;
  69   unsigned long high_pc;
  70
  71   /* Does this unit have a statement list?  */
  72   int has_stmt_list;
  73
  74   /* If any, the offset of the line number table in the .line section.  */
  75   unsigned long stmt_list_offset;
  76
  77   /* If non-zero, a pointer to the first child of this unit.  */
  78   char* first_child;
  79
  80   /* How many line entries?  */
  81   unsigned long line_count;
  82
  83   /* The decoded line number table (line_count entries).  */
  84   struct linenumber* linenumber_table;
  85
  86   /* The list of functions in this unit.  */
  87   struct dwarf1_func* func_list;
  88 };
  89
  90 /* One dwarf1_func for each parsed function die.  */
  91
  92 struct dwarf1_func
  93 {
  94   /* Linked starting from aUnit->func_list.  */
  95   struct dwarf1_func* prev;
  96
  97   /* Name of function.  */
  98   char* name;
  99
 100   /* The highest and lowest address used in the compilation unit.  */
 101   unsigned long low_pc;
 102   unsigned long high_pc;
 103 };
 104
 105 /* Used to return info about a parsed die.  */
 106 struct die_info
 107 {
 108   unsigned long length;
 109   unsigned long sibling;
 110   unsigned long low_pc;
 111   unsigned long high_pc;
 112   unsigned long stmt_list_offset;
 113
 114   char* name;
 115
 116   int has_stmt_list;
 117
 118   unsigned short tag;
 119 };
 120
 121 /* Parsed line number information.  */
 122 struct linenumber
 123 {
 124   /* First address in the line.  */
 125   unsigned long addr;
 126
 127   /* The line number.  */
 128   unsigned long linenumber;
 129 };
 130
 131 /* Find the form of an attr, from the attr field.  */
 132 #define FORM_FROM_ATTR(attr)    ((attr) & 0xF)  /* Implicitly specified.  */
 133
 134 /* Return a newly allocated dwarf1_unit.  It should be cleared and
 135    then attached into the 'stash' at 'stash->lastUnit'.  */
 136
 137 static struct dwarf1_unit*
 138 alloc_dwarf1_unit (struct dwarf1_debug* stash)
 139 {
 140   bfd_size_type amt = sizeof (struct dwarf1_unit);
 141
 142   struct dwarf1_unit* x = bfd_zalloc (stash->abfd, amt);
 143   x->prev = stash->lastUnit;
 144   stash->lastUnit = x;
 145
 146   return x;
 147 }
 148
 149 /* Return a newly allocated dwarf1_func.  It must be cleared and
 150    attached into 'aUnit' at 'aUnit->func_list'.  */
 151
 152 static struct dwarf1_func *
 153 alloc_dwarf1_func (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit)
 154 {
 155   bfd_size_type amt = sizeof (struct dwarf1_func);
 156
 157   struct dwarf1_func* x = bfd_zalloc (stash->abfd, amt);
 158   x->prev = aUnit->func_list;
 159   aUnit->func_list = x;
 160
 161   return x;
 162 }
 163
 164 /* parse_die - parse a Dwarf1 die.
 165    Parse the die starting at 'aDiePtr' into 'aDieInfo'.
 166    'abfd' must be the bfd from which the section that 'aDiePtr'
 167    points to was pulled from.
 168
 169    Return FALSE if the die is invalidly formatted; TRUE otherwise.  */
 170
 171 static bfd_boolean
 172 parse_die (bfd *             abfd,
 173            struct die_info * aDieInfo,
 174            char *            aDiePtr,
 175            char *            aDiePtrEnd)
 176 {
 177   char* this_die = aDiePtr;
 178   char* xptr = this_die;
 179
 180   memset (aDieInfo, 0, sizeof (* aDieInfo));
 181
 182   /* First comes the length.  */
 183   aDieInfo->length = bfd_get_32 (abfd, (bfd_byte *) xptr);
 184   xptr += 4;
 185   if (aDieInfo->length == 0
 186       || (this_die + aDieInfo->length) >= aDiePtrEnd)
 187     return FALSE;
 188   if (aDieInfo->length < 6)
 189     {
 190       /* Just padding bytes.  */
 191       aDieInfo->tag = TAG_padding;
 192       return TRUE;
 193     }
 194
 195   /* Then the tag.  */
 196   aDieInfo->tag = bfd_get_16 (abfd, (bfd_byte *) xptr);
 197   xptr += 2;
 198
 199   /* Then the attributes.  */
 200   while (xptr < (this_die + aDieInfo->length))
 201     {
 202       unsigned short attr;
 203
 204       /* Parse the attribute based on its form.  This section
 205          must handle all dwarf1 forms, but need only handle the
 206          actual attributes that we care about.  */
 207       attr = bfd_get_16 (abfd, (bfd_byte *) xptr);
 208       xptr += 2;
 209
 210       switch (FORM_FROM_ATTR (attr))
 211         {
 212         case FORM_DATA2:
 213           xptr += 2;
 214           break;
 215         case FORM_DATA4:
 216         case FORM_REF:
 217           if (attr == AT_sibling)
 218             aDieInfo->sibling = bfd_get_32 (abfd, (bfd_byte *) xptr);
 219           else if (attr == AT_stmt_list)
 220             {
 221               aDieInfo->stmt_list_offset = bfd_get_32 (abfd, (bfd_byte *) xptr);
 222               aDieInfo->has_stmt_list = 1;
 223             }
 224           xptr += 4;
 225           break;
 226         case FORM_DATA8:
 227           xptr += 8;
 228           break;
 229         case FORM_ADDR:
 230           if (attr == AT_low_pc)
 231             aDieInfo->low_pc = bfd_get_32 (abfd, (bfd_byte *) xptr);
 232           else if (attr == AT_high_pc)
 233             aDieInfo->high_pc = bfd_get_32 (abfd, (bfd_byte *) xptr);
 234           xptr += 4;
 235           break;
 236         case FORM_BLOCK2:
 237           xptr += 2 + bfd_get_16 (abfd, (bfd_byte *) xptr);
 238           break;
 239         case FORM_BLOCK4:
 240           xptr += 4 + bfd_get_32 (abfd, (bfd_byte *) xptr);
 241           break;
 242         case FORM_STRING:
 243           if (attr == AT_name)
 244             aDieInfo->name = xptr;
 245           xptr += strlen (xptr) + 1;
 246           break;
 247         }
 248     }
 249
 250   return TRUE;
 251 }
 252
 253 /* Parse a dwarf1 line number table for 'aUnit->stmt_list_offset'
 254    into 'aUnit->linenumber_table'.  Return FALSE if an error
 255    occurs; TRUE otherwise.  */
 256
 257 static bfd_boolean
 258 parse_line_table (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit)
 259 {
 260   char* xptr;
 261
 262   /* Load the ".line" section from the bfd if we haven't already.  */
 263   if (stash->line_section == 0)
 264     {
 265       asection *msec;
 266       bfd_size_type size;
 267
 268       msec = bfd_get_section_by_name (stash->abfd, ".line");
 269       if (! msec)
 270         return FALSE;
 271
 272       size = msec->rawsize ? msec->rawsize : msec->size;
 273       stash->line_section = bfd_alloc (stash->abfd, size);
 274
 275       if (! stash->line_section)
 276         return FALSE;
 277
 278       if (! bfd_get_section_contents (stash->abfd, msec, stash->line_section,
 279                                       0, size))
 280         {
 281           stash->line_section = 0;
 282           return FALSE;
 283         }
 284
 285       stash->line_section_end = stash->line_section + size;
 286     }
 287
 288   xptr = stash->line_section + aUnit->stmt_list_offset;
 289   if (xptr < stash->line_section_end)
 290     {
 291       unsigned long eachLine;
 292       char *tblend;
 293       unsigned long base;
 294       bfd_size_type amt;
 295
 296       /* First comes the length.  */
 297       tblend = bfd_get_32 (stash->abfd, (bfd_byte *) xptr) + xptr;
 298       xptr += 4;
 299
 300       /* Then the base address for each address in the table.  */
 301       base = bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
 302       xptr += 4;
 303
 304       /* How many line entrys?
 305          10 = 4 (line number) + 2 (pos in line) + 4 (address in line).  */
 306       aUnit->line_count = (tblend - xptr) / 10;
 307
 308       /* Allocate an array for the entries.  */
 309       amt = sizeof (struct linenumber) * aUnit->line_count;
 310       aUnit->linenumber_table = bfd_alloc (stash->abfd, amt);
 311
 312       for (eachLine = 0; eachLine < aUnit->line_count; eachLine++)
 313         {
 314           /* A line number.  */
 315           aUnit->linenumber_table[eachLine].linenumber
 316             = bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
 317           xptr += 4;
 318
 319           /* Skip the position within the line.  */
 320           xptr += 2;
 321
 322           /* And finally the address.  */
 323           aUnit->linenumber_table[eachLine].addr
 324             = base + bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
 325           xptr += 4;
 326         }
 327     }
 328
 329   return TRUE;
 330 }
 331
 332 /* Parse each function die in a compilation unit 'aUnit'.
 333    The first child die of 'aUnit' should be in 'aUnit->first_child',
 334    the result is placed in 'aUnit->func_list'.
 335    Return FALSE if error; TRUE otherwise.  */
 336
 337 static bfd_boolean
 338 parse_functions_in_unit (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit)
 339 {
 340   char* eachDie;
 341
 342   if (aUnit->first_child)
 343     for (eachDie = aUnit->first_child;
 344          eachDie < stash->debug_section_end;
 345          )
 346       {
 347         struct die_info eachDieInfo;
 348
 349         if (! parse_die (stash->abfd, &eachDieInfo, eachDie,
 350                          stash->debug_section_end))
 351           return FALSE;
 352
 353         if (eachDieInfo.tag == TAG_global_subroutine
 354             || eachDieInfo.tag == TAG_subroutine
 355             || eachDieInfo.tag == TAG_inlined_subroutine
 356             || eachDieInfo.tag == TAG_entry_point)
 357           {
 358             struct dwarf1_func* aFunc = alloc_dwarf1_func (stash,aUnit);
 359
 360             aFunc->name = eachDieInfo.name;
 361             aFunc->low_pc = eachDieInfo.low_pc;
 362             aFunc->high_pc = eachDieInfo.high_pc;
 363           }
 364
 365         /* Move to next sibling, if none, end loop */
 366         if (eachDieInfo.sibling)
 367           eachDie = stash->debug_section + eachDieInfo.sibling;
 368         else
 369           break;
 370       }
 371
 372   return TRUE;
 373 }
 374
 375 /* Find the nearest line to 'addr' in 'aUnit'.
 376    Return whether we found the line (or a function) without error.  */
 377
 378 static bfd_boolean
 379 dwarf1_unit_find_nearest_line (struct dwarf1_debug* stash,
 380                                struct dwarf1_unit* aUnit,
 381                                unsigned long addr,
 382                                const char **filename_ptr,
 383                                const char **functionname_ptr,
 384                                unsigned int *linenumber_ptr)
 385 {
 386   int line_p = FALSE;
 387   int func_p = FALSE;
 388
 389   if (aUnit->low_pc <= addr && addr < aUnit->high_pc)
 390     {
 391       if (aUnit->has_stmt_list)
 392         {
 393           unsigned long i;
 394           struct dwarf1_func* eachFunc;
 395
 396           if (! aUnit->linenumber_table)
 397             {
 398               if (! parse_line_table (stash, aUnit))
 399                 return FALSE;
 400             }
 401
 402           if (! aUnit->func_list)
 403             {
 404               if (! parse_functions_in_unit (stash, aUnit))
 405                 return FALSE;
 406             }
 407
 408           for (i = 0; i < aUnit->line_count; i++)
 409             {
 410               if (aUnit->linenumber_table[i].addr <= addr
 411                   && addr < aUnit->linenumber_table[i+1].addr)
 412                 {
 413                   *filename_ptr = aUnit->name;
 414                   *linenumber_ptr = aUnit->linenumber_table[i].linenumber;
 415                   line_p = TRUE;
 416                   break;
 417                 }
 418             }
 419
 420           for (eachFunc = aUnit->func_list;
 421                eachFunc;
 422                eachFunc = eachFunc->prev)
 423             {
 424               if (eachFunc->low_pc <= addr
 425                   && addr < eachFunc->high_pc)
 426                 {
 427                   *functionname_ptr = eachFunc->name;
 428                   func_p = TRUE;
 429                   break;
 430                 }
 431             }
 432         }
 433     }
 434
 435   return line_p || func_p;
 436 }
 437
 438 /* The DWARF 1 version of find_nearest line.
 439    Return TRUE if the line is found without error.  */
 440
 441 bfd_boolean
 442 _bfd_dwarf1_find_nearest_line (bfd *abfd,
 443                                asection *section,
 444                                asymbol **symbols ATTRIBUTE_UNUSED,
 445                                bfd_vma offset,
 446                                const char **filename_ptr,
 447                                const char **functionname_ptr,
 448                                unsigned int *linenumber_ptr)
 449 {
 450   struct dwarf1_debug *stash = elf_tdata (abfd)->dwarf1_find_line_info;
 451
 452   struct dwarf1_unit* eachUnit;
 453
 454   /* What address are we looking for? */
 455   unsigned long addr = (unsigned long)(offset + section->vma);
 456
 457   *filename_ptr = NULL;
 458   *functionname_ptr = NULL;
 459   *linenumber_ptr = 0;
 460
 461   if (! stash)
 462     {
 463       asection *msec;
 464       bfd_size_type size = sizeof (struct dwarf1_debug);
 465
 466       stash = elf_tdata (abfd)->dwarf1_find_line_info
 467         = bfd_zalloc (abfd, size);
 468
 469       if (! stash)
 470         return FALSE;
 471
 472       msec = bfd_get_section_by_name (abfd, ".debug");
 473       if (! msec)
 474         /* No dwarf1 info.  Note that at this point the stash
 475            has been allocated, but contains zeros, this lets
 476            future calls to this function fail quicker.  */
 477         return FALSE;
 478
 479       size = msec->rawsize ? msec->rawsize : msec->size;
 480       stash->debug_section = bfd_alloc (abfd, size);
 481
 482       if (! stash->debug_section)
 483         return FALSE;
 484
 485       if (! bfd_get_section_contents (abfd, msec, stash->debug_section,
 486                                       0, size))
 487         {
 488           stash->debug_section = 0;
 489           return FALSE;
 490         }
 491
 492       stash->debug_section_end = stash->debug_section + size;
 493       stash->currentDie = stash->debug_section;
 494       stash->abfd = abfd;
 495     }
 496
 497   /* A null debug_section indicates that there was no dwarf1 info
 498      or that an error occured while setting up the stash.  */
 499
 500   if (! stash->debug_section)
 501     return FALSE;
 502
 503   /* Look at the previously parsed units to see if any contain
 504      the addr.  */
 505   for (eachUnit = stash->lastUnit; eachUnit; eachUnit = eachUnit->prev)
 506     if (eachUnit->low_pc <= addr && addr < eachUnit->high_pc)
 507       return dwarf1_unit_find_nearest_line (stash, eachUnit, addr,
 508                                             filename_ptr,
 509                                             functionname_ptr,
 510                                             linenumber_ptr);
 511
 512   while (stash->currentDie < stash->debug_section_end)
 513     {
 514       struct die_info aDieInfo;
 515
 516       if (! parse_die (stash->abfd, &aDieInfo, stash->currentDie,
 517                        stash->debug_section_end))
 518         return FALSE;
 519
 520       if (aDieInfo.tag == TAG_compile_unit)
 521         {
 522           struct dwarf1_unit* aUnit
 523             = alloc_dwarf1_unit (stash);
 524
 525           aUnit->name = aDieInfo.name;
 526           aUnit->low_pc = aDieInfo.low_pc;
 527           aUnit->high_pc = aDieInfo.high_pc;
 528           aUnit->has_stmt_list = aDieInfo.has_stmt_list;
 529           aUnit->stmt_list_offset = aDieInfo.stmt_list_offset;
 530
 531           /* A die has a child if it's followed by a die that is
 532              not it's sibling.  */
 533           if (aDieInfo.sibling
 534               && stash->currentDie + aDieInfo.length
 535                     < stash->debug_section_end
 536               && stash->currentDie + aDieInfo.length
 537                     != stash->debug_section + aDieInfo.sibling)
 538             aUnit->first_child = stash->currentDie + aDieInfo.length;
 539           else
 540             aUnit->first_child = 0;
 541
 542           if (aUnit->low_pc <= addr && addr < aUnit->high_pc)
 543             return dwarf1_unit_find_nearest_line (stash, aUnit, addr,
 544                                                   filename_ptr,
 545                                                   functionname_ptr,
 546                                                   linenumber_ptr);
 547         }
 548
 549       if (aDieInfo.sibling != 0)
 550         stash->currentDie = stash->debug_section + aDieInfo.sibling;
 551       else
 552         stash->currentDie += aDieInfo.length;
 553     }
 554
 555   return FALSE;
 556 }