bfd/dwarf1.c

   1 /* DWARF 1 find nearest line (_bfd_dwarf1_find_nearest_line).
   2    Copyright 1998, 1999, 2000, 2001 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 PARAMS ((struct dwarf1_debug *));
 130 static struct dwarf1_func *alloc_dwarf1_func
 131   PARAMS ((struct dwarf1_debug *, struct dwarf1_unit *));
 132 static boolean parse_die PARAMS ((bfd *, struct die_info *, char *, char *));
 133 static boolean parse_line_table
 134   PARAMS ((struct dwarf1_debug *, struct dwarf1_unit *));
 135 static boolean parse_functions_in_unit
 136   PARAMS ((struct dwarf1_debug *, struct dwarf1_unit *));
 137 static boolean dwarf1_unit_find_nearest_line
 138   PARAMS ((struct dwarf1_debug *, struct dwarf1_unit *, unsigned long,
 139            const char **, const char **, unsigned int *));
 140
 141 /* Return a newly allocated dwarf1_unit.  It should be cleared and
 142    then attached into the 'stash' at 'stash->lastUnit'.  */
 143
 144 static struct dwarf1_unit*
 145 alloc_dwarf1_unit (stash)
 146   struct dwarf1_debug* stash;
 147 {
 148   struct dwarf1_unit* x =
 149     (struct dwarf1_unit*) bfd_zalloc (stash->abfd,
 150                                       sizeof (struct dwarf1_unit));
 151   x->prev = stash->lastUnit;
 152   stash->lastUnit = x;
 153
 154   return x;
 155 }
 156
 157 /* Return a newly allocated dwarf1_func.  It must be cleared and
 158    attached into 'aUnit' at 'aUnit->func_list'.  */
 159
 160 static struct dwarf1_func*
 161 alloc_dwarf1_func (stash, aUnit)
 162      struct dwarf1_debug* stash;
 163      struct dwarf1_unit* aUnit;
 164 {
 165   struct dwarf1_func* x =
 166     (struct dwarf1_func*) bfd_zalloc (stash->abfd,
 167                                       sizeof (struct dwarf1_func));
 168   x->prev = aUnit->func_list;
 169   aUnit->func_list = x;
 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 boolean
 182 parse_die (abfd, aDieInfo, aDiePtr, aDiePtrEnd)
 183      bfd* abfd;
 184      struct die_info* aDieInfo;
 185      char*            aDiePtr;
 186      char*            aDiePtrEnd;
 187 {
 188   char* this_die = aDiePtr;
 189   char* xptr = this_die;
 190
 191   memset (aDieInfo,0,sizeof (*aDieInfo));
 192
 193   /* First comes the length.  */
 194   aDieInfo->length = bfd_get_32 (abfd, (bfd_byte *) xptr);
 195   xptr += 4;
 196   if (aDieInfo->length == 0
 197       || (this_die + aDieInfo->length) >= aDiePtrEnd)
 198     return false;
 199   if (aDieInfo->length < 6)
 200     {
 201       /* Just padding bytes.  */
 202       aDieInfo->tag = TAG_padding;
 203       return true;
 204     }
 205
 206   /* Then the tag.  */
 207   aDieInfo->tag = bfd_get_16 (abfd, (bfd_byte *) xptr);
 208   xptr += 2;
 209
 210   /* Then the attributes.  */
 211   while (xptr < (this_die + aDieInfo->length))
 212     {
 213       unsigned short attr;
 214
 215       /* Parse the attribute based on its form.  This section
 216          must handle all dwarf1 forms, but need only handle the
 217          actual attributes that we care about.  */
 218
 219       attr = bfd_get_16 (abfd, (bfd_byte *) xptr);
 220       xptr += 2;
 221
 222       switch (FORM_FROM_ATTR (attr))
 223         {
 224         case FORM_DATA2:
 225           xptr += 2;
 226           break;
 227         case FORM_DATA4:
 228         case FORM_REF:
 229           if (attr == AT_sibling)
 230             aDieInfo->sibling = bfd_get_32 (abfd, (bfd_byte *) xptr);
 231           else if (attr == AT_stmt_list)
 232             {
 233               aDieInfo->stmt_list_offset = bfd_get_32 (abfd, (bfd_byte *) xptr);
 234               aDieInfo->has_stmt_list = 1;
 235             }
 236           xptr += 4;
 237           break;
 238         case FORM_DATA8:
 239           xptr += 8;
 240           break;
 241         case FORM_ADDR:
 242           if (attr == AT_low_pc)
 243             aDieInfo->low_pc = bfd_get_32 (abfd, (bfd_byte *) xptr);
 244           else if (attr == AT_high_pc)
 245             aDieInfo->high_pc = bfd_get_32 (abfd, (bfd_byte *) xptr);
 246           xptr += 4;
 247           break;
 248         case FORM_BLOCK2:
 249           xptr += 2 + bfd_get_16 (abfd, (bfd_byte *) xptr);
 250           break;
 251         case FORM_BLOCK4:
 252           xptr += 4 + bfd_get_32 (abfd, (bfd_byte *) xptr);
 253           break;
 254         case FORM_STRING:
 255           if (attr == AT_name)
 256             aDieInfo->name = xptr;
 257           xptr += strlen (xptr) + 1;
 258           break;
 259         }
 260     }
 261
 262   return true;
 263 }
 264
 265 /* Parse a dwarf1 line number table for 'aUnit->stmt_list_offset'
 266    into 'aUnit->linenumber_table'.  Return false if an error
 267    occurs; true otherwise.  */
 268
 269 static boolean
 270 parse_line_table (stash, aUnit)
 271   struct dwarf1_debug* stash;
 272   struct dwarf1_unit* aUnit;
 273 {
 274   char* xptr;
 275
 276   /* Load the ".line" section from the bfd if we haven't already.  */
 277   if (stash->line_section == 0)
 278     {
 279       asection *msec;
 280       unsigned long size;
 281
 282       msec = bfd_get_section_by_name (stash->abfd, ".line");
 283       if (! msec)
 284         return false;
 285
 286       size = bfd_get_section_size_before_reloc (msec);
 287       stash->line_section = (char *) bfd_alloc (stash->abfd, size);
 288
 289       if (! stash->line_section)
 290         return false;
 291
 292       if (! bfd_get_section_contents (stash->abfd, msec, stash->line_section, 0, size))
 293         {
 294           stash->line_section = 0;
 295           return false;
 296         }
 297
 298       stash->line_section_end = stash->line_section + size;
 299     }
 300
 301   xptr = stash->line_section + aUnit->stmt_list_offset;
 302   if (xptr < stash->line_section_end)
 303     {
 304       unsigned long eachLine;
 305
 306       char* tblend;
 307       unsigned long base;
 308
 309       /* First comes the length.  */
 310       tblend = bfd_get_32 (stash->abfd, (bfd_byte *) xptr) + xptr;
 311       xptr += 4;
 312
 313       /* Then the base address for each address in the table.  */
 314       base = bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
 315       xptr += 4;
 316
 317       /* How many line entrys?
 318          10 = 4 (line number) + 2 (pos in line) + 4 (address in line) */
 319       aUnit->line_count = (tblend - xptr) / 10;
 320
 321       /* Allocate an array for the entries.  */
 322       aUnit->linenumber_table = (struct linenumber *)
 323         bfd_alloc (stash->abfd,
 324                    sizeof (struct linenumber) * aUnit->line_count);
 325
 326       for (eachLine = 0; eachLine < aUnit->line_count; eachLine++)
 327         {
 328           /* A line number.  */
 329           aUnit->linenumber_table[eachLine].linenumber
 330             = bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
 331           xptr += 4;
 332
 333           /* Skip the position within the line.  */
 334           xptr += 2;
 335
 336           /* And finally the address.  */
 337           aUnit->linenumber_table[eachLine].addr
 338             = base + bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
 339           xptr += 4;
 340         }
 341     }
 342
 343   return true;
 344 }
 345
 346 /* Parse each function die in a compilation unit 'aUnit'.
 347    The first child die of 'aUnit' should be in 'aUnit->first_child',
 348    the result is placed in 'aUnit->func_list'.
 349    Return false if error; true otherwise.  */
 350
 351 static boolean
 352 parse_functions_in_unit (stash, aUnit)
 353      struct dwarf1_debug* stash;
 354      struct dwarf1_unit* aUnit;
 355 {
 356   char* eachDie;
 357
 358   if (aUnit->first_child)
 359     for (eachDie = aUnit->first_child;
 360          eachDie < stash->debug_section_end;
 361          )
 362       {
 363         struct die_info eachDieInfo;
 364
 365         if (! parse_die (stash->abfd, &eachDieInfo, eachDie,
 366                          stash->debug_section_end))
 367           return false;
 368
 369         if (eachDieInfo.tag == TAG_global_subroutine
 370             || eachDieInfo.tag == TAG_subroutine
 371             || eachDieInfo.tag == TAG_inlined_subroutine
 372             || eachDieInfo.tag == TAG_entry_point)
 373           {
 374             struct dwarf1_func* aFunc = alloc_dwarf1_func (stash,aUnit);
 375
 376             aFunc->name = eachDieInfo.name;
 377             aFunc->low_pc = eachDieInfo.low_pc;
 378             aFunc->high_pc = eachDieInfo.high_pc;
 379           }
 380
 381         /* Move to next sibling, if none, end loop */
 382         if (eachDieInfo.sibling)
 383           eachDie = stash->debug_section + eachDieInfo.sibling;
 384         else
 385           break;
 386       }
 387
 388   return true;
 389 }
 390
 391 /* Find the nearest line to 'addr' in 'aUnit'.
 392    Return whether we found the line (or a function) without error.  */
 393
 394 static boolean
 395 dwarf1_unit_find_nearest_line (stash, aUnit, addr,
 396                        filename_ptr, functionname_ptr,
 397                        linenumber_ptr)
 398   struct dwarf1_debug* stash;
 399   struct dwarf1_unit* aUnit;
 400   unsigned long addr;
 401   const char **filename_ptr;
 402   const char **functionname_ptr;
 403   unsigned int *linenumber_ptr;
 404 {
 405   int line_p = false;
 406   int func_p = false;
 407
 408   if (aUnit->low_pc <= addr && addr < aUnit->high_pc)
 409     {
 410       if (aUnit->has_stmt_list)
 411         {
 412           unsigned long i;
 413           struct dwarf1_func* eachFunc;
 414
 415           if (! aUnit->linenumber_table)
 416             {
 417               if (! parse_line_table (stash, aUnit))
 418                 return false;
 419             }
 420
 421           if (! aUnit->func_list)
 422             {
 423               if (! parse_functions_in_unit (stash, aUnit))
 424                 return false;
 425             }
 426
 427           for (i = 0; i < aUnit->line_count; i++)
 428             {
 429               if (aUnit->linenumber_table[i].addr <= addr
 430                   && addr < aUnit->linenumber_table[i+1].addr)
 431                 {
 432                   *filename_ptr = aUnit->name;
 433                   *linenumber_ptr = aUnit->linenumber_table[i].linenumber;
 434                   line_p = true;
 435                   break;
 436                 }
 437             }
 438
 439           for (eachFunc = aUnit->func_list;
 440                eachFunc;
 441                eachFunc = eachFunc->prev)
 442             {
 443               if (eachFunc->low_pc <= addr
 444                   && addr < eachFunc->high_pc)
 445                 {
 446                   *functionname_ptr = eachFunc->name;
 447                   func_p = true;
 448                   break;
 449                 }
 450             }
 451         }
 452     }
 453
 454   return line_p || func_p;
 455 }
 456
 457 /* The DWARF 1 version of find_nearest line.
 458    Return true if the line is found without error.  */
 459
 460 boolean
 461 _bfd_dwarf1_find_nearest_line (abfd, section, symbols, offset,
 462                               filename_ptr, functionname_ptr, linenumber_ptr)
 463      bfd *abfd;
 464      asection *section;
 465      asymbol **symbols ATTRIBUTE_UNUSED;
 466      bfd_vma offset;
 467      const char **filename_ptr;
 468      const char **functionname_ptr;
 469      unsigned int *linenumber_ptr;
 470 {
 471   struct dwarf1_debug *stash = elf_tdata (abfd)->dwarf1_find_line_info;
 472
 473   struct dwarf1_unit* eachUnit;
 474
 475   /* What address are we looking for? */
 476   unsigned long addr = (unsigned long)(offset + section->vma);
 477
 478   *filename_ptr = NULL;
 479   *functionname_ptr = NULL;
 480   *linenumber_ptr = 0;
 481
 482   if (! stash)
 483     {
 484       asection *msec;
 485       unsigned long size;
 486
 487       stash = elf_tdata (abfd)->dwarf1_find_line_info =
 488         (struct dwarf1_debug*) bfd_zalloc (abfd, sizeof (struct dwarf1_debug));
 489
 490       if (! stash)
 491         return false;
 492
 493       msec = bfd_get_section_by_name (abfd, ".debug");
 494       if (! msec)
 495         {
 496           /* No dwarf1 info.  Note that at this point the stash
 497              has been allocated, but contains zeros, this lets
 498              future calls to this function fail quicker.  */
 499           return false;
 500         }
 501
 502       size = bfd_get_section_size_before_reloc (msec);
 503       stash->debug_section = (char *) bfd_alloc (abfd, size);
 504
 505       if (! stash->debug_section)
 506         return false;
 507
 508       if (! bfd_get_section_contents (abfd, msec, stash->debug_section, 0, size))
 509         {
 510           stash->debug_section = 0;
 511           return false;
 512         }
 513
 514       stash->debug_section_end = stash->debug_section + size;
 515       stash->currentDie = stash->debug_section;
 516       stash->abfd = abfd;
 517     }
 518
 519   /* A null debug_section indicates that there was no dwarf1 info
 520      or that an error occured while setting up the stash.  */
 521
 522   if (! stash->debug_section)
 523     return false;
 524
 525   /* Look at the previously parsed units to see if any contain
 526      the addr.  */
 527   for (eachUnit = stash->lastUnit; eachUnit; eachUnit = eachUnit->prev)
 528     {
 529       if (eachUnit->low_pc <= addr && addr < eachUnit->high_pc)
 530         return dwarf1_unit_find_nearest_line (stash, eachUnit, addr,
 531                                               filename_ptr,
 532                                               functionname_ptr,
 533                                               linenumber_ptr);
 534     }
 535
 536   while (stash->currentDie < stash->debug_section_end)
 537     {
 538       struct die_info aDieInfo;
 539
 540       if (! parse_die (stash->abfd, &aDieInfo, stash->currentDie,
 541                        stash->debug_section_end))
 542         return false;
 543
 544       if (aDieInfo.tag == TAG_compile_unit)
 545         {
 546           struct dwarf1_unit* aUnit
 547             = alloc_dwarf1_unit (stash);
 548
 549           aUnit->name = aDieInfo.name;
 550           aUnit->low_pc = aDieInfo.low_pc;
 551           aUnit->high_pc = aDieInfo.high_pc;
 552           aUnit->has_stmt_list = aDieInfo.has_stmt_list;
 553           aUnit->stmt_list_offset = aDieInfo.stmt_list_offset;
 554
 555           /* A die has a child if it's followed by a die that is
 556              not it's sibling.  */
 557           if (aDieInfo.sibling
 558               && stash->currentDie + aDieInfo.length
 559                     < stash->debug_section_end
 560               && stash->currentDie + aDieInfo.length
 561                     != stash->debug_section + aDieInfo.sibling)
 562             aUnit->first_child = stash->currentDie + aDieInfo.length;
 563           else
 564             aUnit->first_child = 0;
 565
 566           if (aUnit->low_pc <= addr && addr < aUnit->high_pc)
 567             return dwarf1_unit_find_nearest_line (stash, aUnit, addr,
 568                                                   filename_ptr,
 569                                                   functionname_ptr,
 570                                                   linenumber_ptr);
 571         }
 572
 573       if (aDieInfo.sibling != 0)
 574         stash->currentDie = stash->debug_section + aDieInfo.sibling;
 575       else
 576         stash->currentDie += aDieInfo.length;
 577     }
 578
 579   return false;
 580 }
 581
 582 /* EOF */