bfd/dwarf1.c

   1 /* DWARF 1 find nearest line (_bfd_dwarf1_find_nearest_line).
   2    Copyright 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
   3
   4 Written by Gavin Romig-Koch of Cygnus Solutions (gavin@cygnus.com).
   5
   6 This file is part of BFD.
   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 (at
  11 your option) any later version.
  12
  13 This program is distributed in the hope that it will be useful, but
  14 WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  21
  22 #include "bfd.h"
  23 #include "sysdep.h"
  24 #include "libiberty.h"
  25 #include "libbfd.h"
  26 #include "elf-bfd.h"
  27 #include "elf/dwarf.h"
  28
  29 /* dwarf1_debug is the starting point for all dwarf1 info.  */
  30
  31 struct dwarf1_debug {
  32
  33   /* The bfd we are working with.  */
  34   bfd* abfd;
  35
  36   /* List of already parsed compilation units.  */
  37   struct dwarf1_unit* lastUnit;
  38
  39   /* The buffer for the .debug section.
  40      Zero indicates that the .debug section failed to load.  */
  41   char* debug_section;
  42
  43   /* Pointer to the end of the .debug_info section memory buffer.  */
  44   char* debug_section_end;
  45
  46   /* The buffer for the .line section.  */
  47   char* line_section;
  48
  49   /* End of that buffer.  */
  50   char* line_section_end;
  51
  52   /* The current or next unread die within the .debug section.  */
  53   char* currentDie;
  54 };
  55
  56 /* One dwarf1_unit for each parsed compilation unit die.  */
  57
  58 struct dwarf1_unit {
  59   /* Linked starting from stash->lastUnit.  */
  60   struct dwarf1_unit* prev;
  61
  62   /* Name of the compilation unit.  */
  63   char* name;
  64
  65   /* The highest and lowest address used in the compilation unit.  */
  66   unsigned long low_pc;
  67   unsigned long high_pc;
  68
  69   /* Does this unit have a statement list? */
  70   int has_stmt_list;
  71
  72   /* If any, the offset of the line number table in the .line section.  */
  73   unsigned long stmt_list_offset;
  74
  75   /* If non-zero, a pointer to the first child of this unit.  */
  76   char* first_child;
  77
  78   /* How many line entries? */
  79   unsigned long line_count;
  80
  81   /* The decoded line number table (line_count entries).  */
  82   struct linenumber* linenumber_table;
  83
  84   /* The list of functions in this unit.  */
  85   struct dwarf1_func* func_list;
  86 };
  87
  88 /* One dwarf1_func for each parsed function die.  */
  89
  90 struct dwarf1_func {
  91   /* Linked starting from aUnit->func_list.  */
  92   struct dwarf1_func* prev;
  93
  94   /* Name of function.  */
  95   char* name;
  96
  97   /* The highest and lowest address used in the compilation unit.  */
  98   unsigned long low_pc;
  99   unsigned long high_pc;
 100 };
 101
 102 /* Used to return info about a parsed die.  */
 103 struct die_info {
 104   unsigned long length;
 105   unsigned long sibling;
 106   unsigned long low_pc;
 107   unsigned long high_pc;
 108   unsigned long stmt_list_offset;
 109
 110   char* name;
 111
 112   int has_stmt_list;
 113
 114   unsigned short tag;
 115 };
 116
 117 /* Parsed line number information.  */
 118 struct linenumber {
 119   /* First address in the line.  */
 120   unsigned long addr;
 121
 122   /* The line number.  */
 123   unsigned long linenumber;
 124 };
 125
 126 /* Find the form of an attr, from the attr field.  */
 127 #define FORM_FROM_ATTR(attr)    ((attr) & 0xF)  /* Implicitly specified */
 128
 129 static struct dwarf1_unit *alloc_dwarf1_unit
 130   PARAMS ((struct dwarf1_debug *));
 131 static struct dwarf1_func *alloc_dwarf1_func
 132   PARAMS ((struct dwarf1_debug *, struct dwarf1_unit *));
 133 static bfd_boolean parse_die
 134   PARAMS ((bfd *, struct die_info *, char *, char *));
 135 static bfd_boolean parse_line_table
 136   PARAMS ((struct dwarf1_debug *, struct dwarf1_unit *));
 137 static bfd_boolean parse_functions_in_unit
 138   PARAMS ((struct dwarf1_debug *, struct dwarf1_unit *));
 139 static bfd_boolean dwarf1_unit_find_nearest_line
 140   PARAMS ((struct dwarf1_debug *, struct dwarf1_unit *, unsigned long,
 141            const char **, const char **, unsigned int *));
 142
 143 /* Return a newly allocated dwarf1_unit.  It should be cleared and
 144    then attached into the 'stash' at 'stash->lastUnit'.  */
 145
 146 static struct dwarf1_unit*
 147 alloc_dwarf1_unit (stash)
 148   struct dwarf1_debug* stash;
 149 {
 150   bfd_size_type amt = sizeof (struct dwarf1_unit);
 151
 152   struct dwarf1_unit* x = (struct dwarf1_unit*) bfd_zalloc (stash->abfd, amt);
 153   x->prev = stash->lastUnit;
 154   stash->lastUnit = x;
 155
 156   return x;
 157 }
 158
 159 /* Return a newly allocated dwarf1_func.  It must be cleared and
 160    attached into 'aUnit' at 'aUnit->func_list'.  */
 161
 162 static struct dwarf1_func*
 163 alloc_dwarf1_func (stash, aUnit)
 164      struct dwarf1_debug* stash;
 165      struct dwarf1_unit* aUnit;
 166 {
 167   bfd_size_type amt = sizeof (struct dwarf1_func);
 168
 169   struct dwarf1_func* x = (struct dwarf1_func*) bfd_zalloc (stash->abfd, amt);
 170   x->prev = aUnit->func_list;
 171   aUnit->func_list = x;
 172
 173   return x;
 174 }
 175
 176 /* parse_die - parse a Dwarf1 die.
 177    Parse the die starting at 'aDiePtr' into 'aDieInfo'.
 178    'abfd' must be the bfd from which the section that 'aDiePtr'
 179    points to was pulled from.
 180
 181    Return FALSE if the die is invalidly formatted; TRUE otherwise.  */
 182
 183 static bfd_boolean
 184 parse_die (abfd, aDieInfo, aDiePtr, aDiePtrEnd)
 185      bfd* abfd;
 186      struct die_info* aDieInfo;
 187      char*            aDiePtr;
 188      char*            aDiePtrEnd;
 189 {
 190   char* this_die = aDiePtr;
 191   char* xptr = this_die;
 192
 193   memset (aDieInfo,0,sizeof (*aDieInfo));
 194
 195   /* First comes the length.  */
 196   aDieInfo->length = bfd_get_32 (abfd, (bfd_byte *) xptr);
 197   xptr += 4;
 198   if (aDieInfo->length == 0
 199       || (this_die + aDieInfo->length) >= aDiePtrEnd)
 200     return FALSE;
 201   if (aDieInfo->length < 6)
 202     {
 203       /* Just padding bytes.  */
 204       aDieInfo->tag = TAG_padding;
 205       return TRUE;
 206     }
 207
 208   /* Then the tag.  */
 209   aDieInfo->tag = bfd_get_16 (abfd, (bfd_byte *) xptr);
 210   xptr += 2;
 211
 212   /* Then the attributes.  */
 213   while (xptr < (this_die + aDieInfo->length))
 214     {
 215       unsigned short attr;
 216
 217       /* Parse the attribute based on its form.  This section
 218          must handle all dwarf1 forms, but need only handle the
 219          actual attributes that we care about.  */
 220
 221       attr = bfd_get_16 (abfd, (bfd_byte *) xptr);
 222       xptr += 2;
 223
 224       switch (FORM_FROM_ATTR (attr))
 225         {
 226         case FORM_DATA2:
 227           xptr += 2;
 228           break;
 229         case FORM_DATA4:
 230         case FORM_REF:
 231           if (attr == AT_sibling)
 232             aDieInfo->sibling = bfd_get_32 (abfd, (bfd_byte *) xptr);
 233           else if (attr == AT_stmt_list)
 234             {
 235               aDieInfo->stmt_list_offset = bfd_get_32 (abfd, (bfd_byte *) xptr);
 236               aDieInfo->has_stmt_list = 1;
 237             }
 238           xptr += 4;
 239           break;
 240         case FORM_DATA8:
 241           xptr += 8;
 242           break;
 243         case FORM_ADDR:
 244           if (attr == AT_low_pc)
 245             aDieInfo->low_pc = bfd_get_32 (abfd, (bfd_byte *) xptr);
 246           else if (attr == AT_high_pc)
 247             aDieInfo->high_pc = bfd_get_32 (abfd, (bfd_byte *) xptr);
 248           xptr += 4;
 249           break;
 250         case FORM_BLOCK2:
 251           xptr += 2 + bfd_get_16 (abfd, (bfd_byte *) xptr);
 252           break;
 253         case FORM_BLOCK4:
 254           xptr += 4 + bfd_get_32 (abfd, (bfd_byte *) xptr);
 255           break;
 256         case FORM_STRING:
 257           if (attr == AT_name)
 258             aDieInfo->name = xptr;
 259           xptr += strlen (xptr) + 1;
 260           break;
 261         }
 262     }
 263
 264   return TRUE;
 265 }
 266
 267 /* Parse a dwarf1 line number table for 'aUnit->stmt_list_offset'
 268    into 'aUnit->linenumber_table'.  Return FALSE if an error
 269    occurs; TRUE otherwise.  */
 270
 271 static bfd_boolean
 272 parse_line_table (stash, aUnit)
 273   struct dwarf1_debug* stash;
 274   struct dwarf1_unit* aUnit;
 275 {
 276   char* xptr;
 277
 278   /* Load the ".line" section from the bfd if we haven't already.  */
 279   if (stash->line_section == 0)
 280     {
 281       asection *msec;
 282       bfd_size_type size;
 283
 284       msec = bfd_get_section_by_name (stash->abfd, ".line");
 285       if (! msec)
 286         return FALSE;
 287
 288       size = bfd_get_section_size_before_reloc (msec);
 289       stash->line_section = (char *) bfd_alloc (stash->abfd, size);
 290
 291       if (! stash->line_section)
 292         return FALSE;
 293
 294       if (! bfd_get_section_contents (stash->abfd, msec, stash->line_section,
 295                                       (bfd_vma) 0, size))
 296         {
 297           stash->line_section = 0;
 298           return FALSE;
 299         }
 300
 301       stash->line_section_end = stash->line_section + size;
 302     }
 303
 304   xptr = stash->line_section + aUnit->stmt_list_offset;
 305   if (xptr < stash->line_section_end)
 306     {
 307       unsigned long eachLine;
 308       char *tblend;
 309       unsigned long base;
 310       bfd_size_type amt;
 311
 312       /* First comes the length.  */
 313       tblend = bfd_get_32 (stash->abfd, (bfd_byte *) xptr) + xptr;
 314       xptr += 4;
 315
 316       /* Then the base address for each address in the table.  */
 317       base = bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
 318       xptr += 4;
 319
 320       /* How many line entrys?
 321          10 = 4 (line number) + 2 (pos in line) + 4 (address in line) */
 322       aUnit->line_count = (tblend - xptr) / 10;
 323
 324       /* Allocate an array for the entries.  */
 325       amt = sizeof (struct linenumber) * aUnit->line_count;
 326       aUnit->linenumber_table = ((struct linenumber *)
 327                                  bfd_alloc (stash->abfd, amt));
 328
 329       for (eachLine = 0; eachLine < aUnit->line_count; eachLine++)
 330         {
 331           /* A line number.  */
 332           aUnit->linenumber_table[eachLine].linenumber
 333             = bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
 334           xptr += 4;
 335
 336           /* Skip the position within the line.  */
 337           xptr += 2;
 338
 339           /* And finally the address.  */
 340           aUnit->linenumber_table[eachLine].addr
 341             = base + bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
 342           xptr += 4;
 343         }
 344     }
 345
 346   return TRUE;
 347 }
 348
 349 /* Parse each function die in a compilation unit 'aUnit'.
 350    The first child die of 'aUnit' should be in 'aUnit->first_child',
 351    the result is placed in 'aUnit->func_list'.
 352    Return FALSE if error; TRUE otherwise.  */
 353
 354 static bfd_boolean
 355 parse_functions_in_unit (stash, aUnit)
 356      struct dwarf1_debug* stash;
 357      struct dwarf1_unit* aUnit;
 358 {
 359   char* eachDie;
 360
 361   if (aUnit->first_child)
 362     for (eachDie = aUnit->first_child;
 363          eachDie < stash->debug_section_end;
 364          )
 365       {
 366         struct die_info eachDieInfo;
 367
 368         if (! parse_die (stash->abfd, &eachDieInfo, eachDie,
 369                          stash->debug_section_end))
 370           return FALSE;
 371
 372         if (eachDieInfo.tag == TAG_global_subroutine
 373             || eachDieInfo.tag == TAG_subroutine
 374             || eachDieInfo.tag == TAG_inlined_subroutine
 375             || eachDieInfo.tag == TAG_entry_point)
 376           {
 377             struct dwarf1_func* aFunc = alloc_dwarf1_func (stash,aUnit);
 378
 379             aFunc->name = eachDieInfo.name;
 380             aFunc->low_pc = eachDieInfo.low_pc;
 381             aFunc->high_pc = eachDieInfo.high_pc;
 382           }
 383
 384         /* Move to next sibling, if none, end loop */
 385         if (eachDieInfo.sibling)
 386           eachDie = stash->debug_section + eachDieInfo.sibling;
 387         else
 388           break;
 389       }
 390
 391   return TRUE;
 392 }
 393
 394 /* Find the nearest line to 'addr' in 'aUnit'.
 395    Return whether we found the line (or a function) without error.  */
 396
 397 static bfd_boolean
 398 dwarf1_unit_find_nearest_line (stash, aUnit, addr,
 399                        filename_ptr, functionname_ptr,
 400                        linenumber_ptr)
 401   struct dwarf1_debug* stash;
 402   struct dwarf1_unit* aUnit;
 403   unsigned long addr;
 404   const char **filename_ptr;
 405   const char **functionname_ptr;
 406   unsigned int *linenumber_ptr;
 407 {
 408   int line_p = FALSE;
 409   int func_p = FALSE;
 410
 411   if (aUnit->low_pc <= addr && addr < aUnit->high_pc)
 412     {
 413       if (aUnit->has_stmt_list)
 414         {
 415           unsigned long i;
 416           struct dwarf1_func* eachFunc;
 417
 418           if (! aUnit->linenumber_table)
 419             {
 420               if (! parse_line_table (stash, aUnit))
 421                 return FALSE;
 422             }
 423
 424           if (! aUnit->func_list)
 425             {
 426               if (! parse_functions_in_unit (stash, aUnit))
 427                 return FALSE;
 428             }
 429
 430           for (i = 0; i < aUnit->line_count; i++)
 431             {
 432               if (aUnit->linenumber_table[i].addr <= addr
 433                   && addr < aUnit->linenumber_table[i+1].addr)
 434                 {
 435                   *filename_ptr = aUnit->name;
 436                   *linenumber_ptr = aUnit->linenumber_table[i].linenumber;
 437                   line_p = TRUE;
 438                   break;
 439                 }
 440             }
 441
 442           for (eachFunc = aUnit->func_list;
 443                eachFunc;
 444                eachFunc = eachFunc->prev)
 445             {
 446               if (eachFunc->low_pc <= addr
 447                   && addr < eachFunc->high_pc)
 448                 {
 449                   *functionname_ptr = eachFunc->name;
 450                   func_p = TRUE;
 451                   break;
 452                 }
 453             }
 454         }
 455     }
 456
 457   return line_p || func_p;
 458 }
 459
 460 /* The DWARF 1 version of find_nearest line.
 461    Return TRUE if the line is found without error.  */
 462
 463 bfd_boolean
 464 _bfd_dwarf1_find_nearest_line (abfd, section, symbols, offset,
 465                               filename_ptr, functionname_ptr, linenumber_ptr)
 466      bfd *abfd;
 467      asection *section;
 468      asymbol **symbols ATTRIBUTE_UNUSED;
 469      bfd_vma offset;
 470      const char **filename_ptr;
 471      const char **functionname_ptr;
 472      unsigned int *linenumber_ptr;
 473 {
 474   struct dwarf1_debug *stash = elf_tdata (abfd)->dwarf1_find_line_info;
 475
 476   struct dwarf1_unit* eachUnit;
 477
 478   /* What address are we looking for? */
 479   unsigned long addr = (unsigned long)(offset + section->vma);
 480
 481   *filename_ptr = NULL;
 482   *functionname_ptr = NULL;
 483   *linenumber_ptr = 0;
 484
 485   if (! stash)
 486     {
 487       asection *msec;
 488       bfd_size_type size = sizeof (struct dwarf1_debug);
 489
 490       stash = elf_tdata (abfd)->dwarf1_find_line_info
 491         = (struct dwarf1_debug *) bfd_zalloc (abfd, size);
 492
 493       if (! stash)
 494         return FALSE;
 495
 496       msec = bfd_get_section_by_name (abfd, ".debug");
 497       if (! msec)
 498         {
 499           /* No dwarf1 info.  Note that at this point the stash
 500              has been allocated, but contains zeros, this lets
 501              future calls to this function fail quicker.  */
 502           return FALSE;
 503         }
 504
 505       size = bfd_get_section_size_before_reloc (msec);
 506       stash->debug_section = (char *) bfd_alloc (abfd, size);
 507
 508       if (! stash->debug_section)
 509         return FALSE;
 510
 511       if (! bfd_get_section_contents (abfd, msec, stash->debug_section,
 512                                       (bfd_vma) 0, size))
 513         {
 514           stash->debug_section = 0;
 515           return FALSE;
 516         }
 517
 518       stash->debug_section_end = stash->debug_section + size;
 519       stash->currentDie = stash->debug_section;
 520       stash->abfd = abfd;
 521     }
 522
 523   /* A null debug_section indicates that there was no dwarf1 info
 524      or that an error occured while setting up the stash.  */
 525
 526   if (! stash->debug_section)
 527     return FALSE;
 528
 529   /* Look at the previously parsed units to see if any contain
 530      the addr.  */
 531   for (eachUnit = stash->lastUnit; eachUnit; eachUnit = eachUnit->prev)
 532     {
 533       if (eachUnit->low_pc <= addr && addr < eachUnit->high_pc)
 534         return dwarf1_unit_find_nearest_line (stash, eachUnit, addr,
 535                                               filename_ptr,
 536                                               functionname_ptr,
 537                                               linenumber_ptr);
 538     }
 539
 540   while (stash->currentDie < stash->debug_section_end)
 541     {
 542       struct die_info aDieInfo;
 543
 544       if (! parse_die (stash->abfd, &aDieInfo, stash->currentDie,
 545                        stash->debug_section_end))
 546         return FALSE;
 547
 548       if (aDieInfo.tag == TAG_compile_unit)
 549         {
 550           struct dwarf1_unit* aUnit
 551             = alloc_dwarf1_unit (stash);
 552
 553           aUnit->name = aDieInfo.name;
 554           aUnit->low_pc = aDieInfo.low_pc;
 555           aUnit->high_pc = aDieInfo.high_pc;
 556           aUnit->has_stmt_list = aDieInfo.has_stmt_list;
 557           aUnit->stmt_list_offset = aDieInfo.stmt_list_offset;
 558
 559           /* A die has a child if it's followed by a die that is
 560              not it's sibling.  */
 561           if (aDieInfo.sibling
 562               && stash->currentDie + aDieInfo.length
 563                     < stash->debug_section_end
 564               && stash->currentDie + aDieInfo.length
 565                     != stash->debug_section + aDieInfo.sibling)
 566             aUnit->first_child = stash->currentDie + aDieInfo.length;
 567           else
 568             aUnit->first_child = 0;
 569
 570           if (aUnit->low_pc <= addr && addr < aUnit->high_pc)
 571             return dwarf1_unit_find_nearest_line (stash, aUnit, addr,
 572                                                   filename_ptr,
 573                                                   functionname_ptr,
 574                                                   linenumber_ptr);
 575         }
 576
 577       if (aDieInfo.sibling != 0)
 578         stash->currentDie = stash->debug_section + aDieInfo.sibling;
 579       else
 580         stash->currentDie += aDieInfo.length;
 581     }
 582
 583   return FALSE;
 584 }
 585
 586 /* EOF */