bfd/dwarf1.c

   1 /* DWARF 1 find nearest line (_bfd_dwarf1_find_nearest_line).
   2    Copyright 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2007
   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 3 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,
  22    MA 02110-1301, USA.  */
  23
  24 #include "sysdep.h"
  25 #include "bfd.h"
  26 #include "libiberty.h"
  27 #include "libbfd.h"
  28 #include "elf-bfd.h"
  29 #include "elf/dwarf.h"
  30
  31 /* dwarf1_debug is the starting point for all dwarf1 info.  */
  32
  33 struct dwarf1_debug
  34 {
  35   /* The bfd we are working with.  */
  36   bfd* abfd;
  37
  38   /* Pointer to the symbol table.  */
  39   asymbol** syms;
  40
  41   /* List of already parsed compilation units.  */
  42   struct dwarf1_unit* lastUnit;
  43
  44   /* The buffer for the .debug section.
  45      Zero indicates that the .debug section failed to load.  */
  46   bfd_byte *debug_section;
  47
  48   /* Pointer to the end of the .debug_info section memory buffer.  */
  49   bfd_byte *debug_section_end;
  50
  51   /* The buffer for the .line section.  */
  52   bfd_byte *line_section;
  53
  54   /* End of that buffer.  */
  55   bfd_byte *line_section_end;
  56
  57   /* The current or next unread die within the .debug section.  */
  58   bfd_byte *currentDie;
  59 };
  60
  61 /* One dwarf1_unit for each parsed compilation unit die.  */
  62
  63 struct dwarf1_unit
  64 {
  65   /* Linked starting from stash->lastUnit.  */
  66   struct dwarf1_unit* prev;
  67
  68   /* Name of the compilation unit.  */
  69   char *name;
  70
  71   /* The highest and lowest address used in the compilation unit.  */
  72   unsigned long low_pc;
  73   unsigned long high_pc;
  74
  75   /* Does this unit have a statement list?  */
  76   int has_stmt_list;
  77
  78   /* If any, the offset of the line number table in the .line section.  */
  79   unsigned long stmt_list_offset;
  80
  81   /* If non-zero, a pointer to the first child of this unit.  */
  82   bfd_byte *first_child;
  83
  84   /* How many line entries?  */
  85   unsigned long line_count;
  86
  87   /* The decoded line number table (line_count entries).  */
  88   struct linenumber* linenumber_table;
  89
  90   /* The list of functions in this unit.  */
  91   struct dwarf1_func* func_list;
  92 };
  93
  94 /* One dwarf1_func for each parsed function die.  */
  95
  96 struct dwarf1_func
  97 {
  98   /* Linked starting from aUnit->func_list.  */
  99   struct dwarf1_func* prev;
 100
 101   /* Name of function.  */
 102   char* name;
 103
 104   /* The highest and lowest address used in the compilation unit.  */
 105   unsigned long low_pc;
 106   unsigned long high_pc;
 107 };
 108
 109 /* Used to return info about a parsed die.  */
 110 struct die_info
 111 {
 112   unsigned long length;
 113   unsigned long sibling;
 114   unsigned long low_pc;
 115   unsigned long high_pc;
 116   unsigned long stmt_list_offset;
 117
 118   char* name;
 119
 120   int has_stmt_list;
 121
 122   unsigned short tag;
 123 };
 124
 125 /* Parsed line number information.  */
 126 struct linenumber
 127 {
 128   /* First address in the line.  */
 129   unsigned long addr;
 130
 131   /* The line number.  */
 132   unsigned long linenumber;
 133 };
 134
 135 /* Find the form of an attr, from the attr field.  */
 136 #define FORM_FROM_ATTR(attr)    ((attr) & 0xF)  /* Implicitly specified.  */
 137
 138 /* Return a newly allocated dwarf1_unit.  It should be cleared and
 139    then attached into the 'stash' at 'stash->lastUnit'.  */
 140
 141 static struct dwarf1_unit*
 142 alloc_dwarf1_unit (struct dwarf1_debug* stash)
 143 {
 144   bfd_size_type amt = sizeof (struct dwarf1_unit);
 145
 146   struct dwarf1_unit* x = bfd_zalloc (stash->abfd, amt);
 147   if (x)
 148     {
 149       x->prev = stash->lastUnit;
 150       stash->lastUnit = x;
 151     }
 152
 153   return x;
 154 }
 155
 156 /* Return a newly allocated dwarf1_func.  It must be cleared and
 157    attached into 'aUnit' at 'aUnit->func_list'.  */
 158
 159 static struct dwarf1_func *
 160 alloc_dwarf1_func (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit)
 161 {
 162   bfd_size_type amt = sizeof (struct dwarf1_func);
 163
 164   struct dwarf1_func* x = bfd_zalloc (stash->abfd, amt);
 165   if (x)
 166     {
 167       x->prev = aUnit->func_list;
 168       aUnit->func_list = x;
 169     }
 170
 171   return x;
 172 }
 173
 174 /* parse_die - parse a Dwarf1 die.
 175    Parse the die starting at 'aDiePtr' into 'aDieInfo'.
 176    'abfd' must be the bfd from which the section that 'aDiePtr'
 177    points to was pulled from.
 178
 179    Return FALSE if the die is invalidly formatted; TRUE otherwise.  */
 180
 181 static bfd_boolean
 182 parse_die (bfd *             abfd,
 183            struct die_info * aDieInfo,
 184            bfd_byte *        aDiePtr,
 185            bfd_byte *        aDiePtrEnd)
 186 {
 187   bfd_byte *this_die = aDiePtr;
 188   bfd_byte *xptr = this_die;
 189
 190   memset (aDieInfo, 0, sizeof (* aDieInfo));
 191
 192   /* First comes the length.  */
 193   aDieInfo->length = bfd_get_32 (abfd, (bfd_byte *) xptr);
 194   xptr += 4;
 195   if (aDieInfo->length == 0
 196       || (this_die + aDieInfo->length) >= aDiePtrEnd)
 197     return FALSE;
 198   if (aDieInfo->length < 6)
 199     {
 200       /* Just padding bytes.  */
 201       aDieInfo->tag = TAG_padding;
 202       return TRUE;
 203     }
 204
 205   /* Then the tag.  */
 206   aDieInfo->tag = bfd_get_16 (abfd, (bfd_byte *) xptr);
 207   xptr += 2;
 208
 209   /* Then the attributes.  */
 210   while (xptr < (this_die + aDieInfo->length))
 211     {
 212       unsigned short attr;
 213
 214       /* Parse the attribute based on its form.  This section
 215          must handle all dwarf1 forms, but need only handle the
 216          actual attributes that we care about.  */
 217       attr = bfd_get_16 (abfd, (bfd_byte *) xptr);
 218       xptr += 2;
 219
 220       switch (FORM_FROM_ATTR (attr))
 221         {
 222         case FORM_DATA2:
 223           xptr += 2;
 224           break;
 225         case FORM_DATA4:
 226         case FORM_REF:
 227           if (attr == AT_sibling)
 228             aDieInfo->sibling = bfd_get_32 (abfd, (bfd_byte *) xptr);
 229           else if (attr == AT_stmt_list)
 230             {
 231               aDieInfo->stmt_list_offset = bfd_get_32 (abfd, (bfd_byte *) xptr);
 232               aDieInfo->has_stmt_list = 1;
 233             }
 234           xptr += 4;
 235           break;
 236         case FORM_DATA8:
 237           xptr += 8;
 238           break;
 239         case FORM_ADDR:
 240           if (attr == AT_low_pc)
 241             aDieInfo->low_pc = bfd_get_32 (abfd, (bfd_byte *) xptr);
 242           else if (attr == AT_high_pc)
 243             aDieInfo->high_pc = bfd_get_32 (abfd, (bfd_byte *) xptr);
 244           xptr += 4;
 245           break;
 246         case FORM_BLOCK2:
 247           xptr += 2 + bfd_get_16 (abfd, (bfd_byte *) xptr);
 248           break;
 249         case FORM_BLOCK4:
 250           xptr += 4 + bfd_get_32 (abfd, (bfd_byte *) xptr);
 251           break;
 252         case FORM_STRING:
 253           if (attr == AT_name)
 254             aDieInfo->name = (char *)xptr;
 255           xptr += strlen (aDieInfo->name) + 1;
 256           break;
 257         }
 258     }
 259
 260   return TRUE;
 261 }
 262
 263 /* Parse a dwarf1 line number table for 'aUnit->stmt_list_offset'
 264    into 'aUnit->linenumber_table'.  Return FALSE if an error
 265    occurs; TRUE otherwise.  */
 266
 267 static bfd_boolean
 268 parse_line_table (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit)
 269 {
 270   bfd_byte *xptr;
 271
 272   /* Load the ".line" section from the bfd if we haven't already.  */
 273   if (stash->line_section == 0)
 274     {
 275       asection *msec;
 276       bfd_size_type size;
 277
 278       msec = bfd_get_section_by_name (stash->abfd, ".line");
 279       if (! msec)
 280         return FALSE;
 281
 282       size = msec->rawsize ? msec->rawsize : msec->size;
 283       stash->line_section
 284         = bfd_simple_get_relocated_section_contents
 285         (stash->abfd, msec, NULL, stash->syms);
 286
 287       if (! stash->line_section)
 288         return FALSE;
 289
 290       stash->line_section_end = stash->line_section + size;
 291     }
 292
 293   xptr = stash->line_section + aUnit->stmt_list_offset;
 294   if (xptr < stash->line_section_end)
 295     {
 296       unsigned long eachLine;
 297       bfd_byte *tblend;
 298       unsigned long base;
 299       bfd_size_type amt;
 300
 301       /* First comes the length.  */
 302       tblend = bfd_get_32 (stash->abfd, (bfd_byte *) xptr) + xptr;
 303       xptr += 4;
 304
 305       /* Then the base address for each address in the table.  */
 306       base = bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
 307       xptr += 4;
 308
 309       /* How many line entrys?
 310          10 = 4 (line number) + 2 (pos in line) + 4 (address in line).  */
 311       aUnit->line_count = (tblend - xptr) / 10;
 312
 313       /* Allocate an array for the entries.  */
 314       amt = sizeof (struct linenumber) * aUnit->line_count;
 315       aUnit->linenumber_table = bfd_alloc (stash->abfd, amt);
 316       if (!aUnit->linenumber_table)
 317         return FALSE;
 318
 319       for (eachLine = 0; eachLine < aUnit->line_count; eachLine++)
 320         {
 321           /* A line number.  */
 322           aUnit->linenumber_table[eachLine].linenumber
 323             = bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
 324           xptr += 4;
 325
 326           /* Skip the position within the line.  */
 327           xptr += 2;
 328
 329           /* And finally the address.  */
 330           aUnit->linenumber_table[eachLine].addr
 331             = base + bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
 332           xptr += 4;
 333         }
 334     }
 335
 336   return TRUE;
 337 }
 338
 339 /* Parse each function die in a compilation unit 'aUnit'.
 340    The first child die of 'aUnit' should be in 'aUnit->first_child',
 341    the result is placed in 'aUnit->func_list'.
 342    Return FALSE if error; TRUE otherwise.  */
 343
 344 static bfd_boolean
 345 parse_functions_in_unit (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit)
 346 {
 347   bfd_byte *eachDie;
 348
 349   if (aUnit->first_child)
 350     for (eachDie = aUnit->first_child;
 351          eachDie < stash->debug_section_end;
 352          )
 353       {
 354         struct die_info eachDieInfo;
 355
 356         if (! parse_die (stash->abfd, &eachDieInfo, eachDie,
 357                          stash->debug_section_end))
 358           return FALSE;
 359
 360         if (eachDieInfo.tag == TAG_global_subroutine
 361             || eachDieInfo.tag == TAG_subroutine
 362             || eachDieInfo.tag == TAG_inlined_subroutine
 363             || eachDieInfo.tag == TAG_entry_point)
 364           {
 365             struct dwarf1_func* aFunc = alloc_dwarf1_func (stash,aUnit);
 366             if (!aFunc)
 367               return FALSE;
 368
 369             aFunc->name = eachDieInfo.name;
 370             aFunc->low_pc = eachDieInfo.low_pc;
 371             aFunc->high_pc = eachDieInfo.high_pc;
 372           }
 373
 374         /* Move to next sibling, if none, end loop */
 375         if (eachDieInfo.sibling)
 376           eachDie = stash->debug_section + eachDieInfo.sibling;
 377         else
 378           break;
 379       }
 380
 381   return TRUE;
 382 }
 383
 384 /* Find the nearest line to 'addr' in 'aUnit'.
 385    Return whether we found the line (or a function) without error.  */
 386
 387 static bfd_boolean
 388 dwarf1_unit_find_nearest_line (struct dwarf1_debug* stash,
 389                                struct dwarf1_unit* aUnit,
 390                                unsigned long addr,
 391                                const char **filename_ptr,
 392                                const char **functionname_ptr,
 393                                unsigned int *linenumber_ptr)
 394 {
 395   int line_p = FALSE;
 396   int func_p = FALSE;
 397
 398   if (aUnit->low_pc <= addr && addr < aUnit->high_pc)
 399     {
 400       if (aUnit->has_stmt_list)
 401         {
 402           unsigned long i;
 403           struct dwarf1_func* eachFunc;
 404
 405           if (! aUnit->linenumber_table)
 406             {
 407               if (! parse_line_table (stash, aUnit))
 408                 return FALSE;
 409             }
 410
 411           if (! aUnit->func_list)
 412             {
 413               if (! parse_functions_in_unit (stash, aUnit))
 414                 return FALSE;
 415             }
 416
 417           for (i = 0; i < aUnit->line_count; i++)
 418             {
 419               if (aUnit->linenumber_table[i].addr <= addr
 420                   && addr < aUnit->linenumber_table[i+1].addr)
 421                 {
 422                   *filename_ptr = aUnit->name;
 423                   *linenumber_ptr = aUnit->linenumber_table[i].linenumber;
 424                   line_p = TRUE;
 425                   break;
 426                 }
 427             }
 428
 429           for (eachFunc = aUnit->func_list;
 430                eachFunc;
 431                eachFunc = eachFunc->prev)
 432             {
 433               if (eachFunc->low_pc <= addr
 434                   && addr < eachFunc->high_pc)
 435                 {
 436                   *functionname_ptr = eachFunc->name;
 437                   func_p = TRUE;
 438                   break;
 439                 }
 440             }
 441         }
 442     }
 443
 444   return line_p || func_p;
 445 }
 446
 447 /* The DWARF 1 version of find_nearest line.
 448    Return TRUE if the line is found without error.  */
 449
 450 bfd_boolean
 451 _bfd_dwarf1_find_nearest_line (bfd *abfd,
 452                                asection *section,
 453                                asymbol **symbols,
 454                                bfd_vma offset,
 455                                const char **filename_ptr,
 456                                const char **functionname_ptr,
 457                                unsigned int *linenumber_ptr)
 458 {
 459   struct dwarf1_debug *stash = elf_tdata (abfd)->dwarf1_find_line_info;
 460
 461   struct dwarf1_unit* eachUnit;
 462
 463   /* What address are we looking for? */
 464   unsigned long addr = (unsigned long)(offset + section->vma);
 465
 466   *filename_ptr = NULL;
 467   *functionname_ptr = NULL;
 468   *linenumber_ptr = 0;
 469
 470   if (! stash)
 471     {
 472       asection *msec;
 473       bfd_size_type size = sizeof (struct dwarf1_debug);
 474
 475       stash = elf_tdata (abfd)->dwarf1_find_line_info
 476         = bfd_zalloc (abfd, size);
 477
 478       if (! stash)
 479         return FALSE;
 480
 481       msec = bfd_get_section_by_name (abfd, ".debug");
 482       if (! msec)
 483         /* No dwarf1 info.  Note that at this point the stash
 484            has been allocated, but contains zeros, this lets
 485            future calls to this function fail quicker.  */
 486         return FALSE;
 487
 488       size = msec->rawsize ? msec->rawsize : msec->size;
 489       stash->debug_section
 490         = bfd_simple_get_relocated_section_contents (abfd, msec, NULL,
 491                                                      symbols);
 492
 493       if (! stash->debug_section)
 494         return FALSE;
 495
 496       stash->debug_section_end = stash->debug_section + size;
 497       stash->currentDie = stash->debug_section;
 498       stash->abfd = abfd;
 499       stash->syms = symbols;
 500     }
 501
 502   /* A null debug_section indicates that there was no dwarf1 info
 503      or that an error occured while setting up the stash.  */
 504
 505   if (! stash->debug_section)
 506     return FALSE;
 507
 508   /* Look at the previously parsed units to see if any contain
 509      the addr.  */
 510   for (eachUnit = stash->lastUnit; eachUnit; eachUnit = eachUnit->prev)
 511     if (eachUnit->low_pc <= addr && addr < eachUnit->high_pc)
 512       return dwarf1_unit_find_nearest_line (stash, eachUnit, addr,
 513                                             filename_ptr,
 514                                             functionname_ptr,
 515                                             linenumber_ptr);
 516
 517   while (stash->currentDie < stash->debug_section_end)
 518     {
 519       struct die_info aDieInfo;
 520
 521       if (! parse_die (stash->abfd, &aDieInfo, stash->currentDie,
 522                        stash->debug_section_end))
 523         return FALSE;
 524
 525       if (aDieInfo.tag == TAG_compile_unit)
 526         {
 527           struct dwarf1_unit* aUnit
 528             = alloc_dwarf1_unit (stash);
 529           if (!aUnit)
 530             return FALSE;
 531
 532           aUnit->name = aDieInfo.name;
 533           aUnit->low_pc = aDieInfo.low_pc;
 534           aUnit->high_pc = aDieInfo.high_pc;
 535           aUnit->has_stmt_list = aDieInfo.has_stmt_list;
 536           aUnit->stmt_list_offset = aDieInfo.stmt_list_offset;
 537
 538           /* A die has a child if it's followed by a die that is
 539              not it's sibling.  */
 540           if (aDieInfo.sibling
 541               && stash->currentDie + aDieInfo.length
 542                     < stash->debug_section_end
 543               && stash->currentDie + aDieInfo.length
 544                     != stash->debug_section + aDieInfo.sibling)
 545             aUnit->first_child = stash->currentDie + aDieInfo.length;
 546           else
 547             aUnit->first_child = 0;
 548
 549           if (aUnit->low_pc <= addr && addr < aUnit->high_pc)
 550             return dwarf1_unit_find_nearest_line (stash, aUnit, addr,
 551                                                   filename_ptr,
 552                                                   functionname_ptr,
 553                                                   linenumber_ptr);
 554         }
 555
 556       if (aDieInfo.sibling != 0)
 557         stash->currentDie = stash->debug_section + aDieInfo.sibling;
 558       else
 559         stash->currentDie += aDieInfo.length;
 560     }
 561
 562   return FALSE;
 563 }