bfd/dwarf1.c

   1 /* DWARF 1 find nearest line (_bfd_dwarf1_find_nearest_line).
   2    Copyright 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2007, 2008, 2009, 2010
   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 = (struct dwarf1_unit *) 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 = (struct dwarf1_func *) 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 ((char *) xptr) + 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 = (struct linenumber *) bfd_alloc (stash->abfd,
 316                                                                  amt);
 317       if (!aUnit->linenumber_table)
 318         return FALSE;
 319
 320       for (eachLine = 0; eachLine < aUnit->line_count; eachLine++)
 321         {
 322           /* A line number.  */
 323           aUnit->linenumber_table[eachLine].linenumber
 324             = bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
 325           xptr += 4;
 326
 327           /* Skip the position within the line.  */
 328           xptr += 2;
 329
 330           /* And finally the address.  */
 331           aUnit->linenumber_table[eachLine].addr
 332             = base + bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
 333           xptr += 4;
 334         }
 335     }
 336
 337   return TRUE;
 338 }
 339
 340 /* Parse each function die in a compilation unit 'aUnit'.
 341    The first child die of 'aUnit' should be in 'aUnit->first_child',
 342    the result is placed in 'aUnit->func_list'.
 343    Return FALSE if error; TRUE otherwise.  */
 344
 345 static bfd_boolean
 346 parse_functions_in_unit (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit)
 347 {
 348   bfd_byte *eachDie;
 349
 350   if (aUnit->first_child)
 351     for (eachDie = aUnit->first_child;
 352          eachDie < stash->debug_section_end;
 353          )
 354       {
 355         struct die_info eachDieInfo;
 356
 357         if (! parse_die (stash->abfd, &eachDieInfo, eachDie,
 358                          stash->debug_section_end))
 359           return FALSE;
 360
 361         if (eachDieInfo.tag == TAG_global_subroutine
 362             || eachDieInfo.tag == TAG_subroutine
 363             || eachDieInfo.tag == TAG_inlined_subroutine
 364             || eachDieInfo.tag == TAG_entry_point)
 365           {
 366             struct dwarf1_func* aFunc = alloc_dwarf1_func (stash,aUnit);
 367             if (!aFunc)
 368               return FALSE;
 369
 370             aFunc->name = eachDieInfo.name;
 371             aFunc->low_pc = eachDieInfo.low_pc;
 372             aFunc->high_pc = eachDieInfo.high_pc;
 373           }
 374
 375         /* Move to next sibling, if none, end loop */
 376         if (eachDieInfo.sibling)
 377           eachDie = stash->debug_section + eachDieInfo.sibling;
 378         else
 379           break;
 380       }
 381
 382   return TRUE;
 383 }
 384
 385 /* Find the nearest line to 'addr' in 'aUnit'.
 386    Return whether we found the line (or a function) without error.  */
 387
 388 static bfd_boolean
 389 dwarf1_unit_find_nearest_line (struct dwarf1_debug* stash,
 390                                struct dwarf1_unit* aUnit,
 391                                unsigned long addr,
 392                                const char **filename_ptr,
 393                                const char **functionname_ptr,
 394                                unsigned int *linenumber_ptr)
 395 {
 396   int line_p = FALSE;
 397   int func_p = FALSE;
 398
 399   if (aUnit->low_pc <= addr && addr < aUnit->high_pc)
 400     {
 401       if (aUnit->has_stmt_list)
 402         {
 403           unsigned long i;
 404           struct dwarf1_func* eachFunc;
 405
 406           if (! aUnit->linenumber_table)
 407             {
 408               if (! parse_line_table (stash, aUnit))
 409                 return FALSE;
 410             }
 411
 412           if (! aUnit->func_list)
 413             {
 414               if (! parse_functions_in_unit (stash, aUnit))
 415                 return FALSE;
 416             }
 417
 418           for (i = 0; i < aUnit->line_count; i++)
 419             {
 420               if (aUnit->linenumber_table[i].addr <= addr
 421                   && addr < aUnit->linenumber_table[i+1].addr)
 422                 {
 423                   *filename_ptr = aUnit->name;
 424                   *linenumber_ptr = aUnit->linenumber_table[i].linenumber;
 425                   line_p = TRUE;
 426                   break;
 427                 }
 428             }
 429
 430           for (eachFunc = aUnit->func_list;
 431                eachFunc;
 432                eachFunc = eachFunc->prev)
 433             {
 434               if (eachFunc->low_pc <= addr
 435                   && addr < eachFunc->high_pc)
 436                 {
 437                   *functionname_ptr = eachFunc->name;
 438                   func_p = TRUE;
 439                   break;
 440                 }
 441             }
 442         }
 443     }
 444
 445   return line_p || func_p;
 446 }
 447
 448 /* The DWARF 1 version of find_nearest line.
 449    Return TRUE if the line is found without error.  */
 450
 451 bfd_boolean
 452 _bfd_dwarf1_find_nearest_line (bfd *abfd,
 453                                asection *section,
 454                                asymbol **symbols,
 455                                bfd_vma offset,
 456                                const char **filename_ptr,
 457                                const char **functionname_ptr,
 458                                unsigned int *linenumber_ptr)
 459 {
 460   struct dwarf1_debug *stash = elf_tdata (abfd)->dwarf1_find_line_info;
 461
 462   struct dwarf1_unit* eachUnit;
 463
 464   /* What address are we looking for? */
 465   unsigned long addr = (unsigned long)(offset + section->vma);
 466
 467   *filename_ptr = NULL;
 468   *functionname_ptr = NULL;
 469   *linenumber_ptr = 0;
 470
 471   if (! stash)
 472     {
 473       asection *msec;
 474       bfd_size_type size = sizeof (struct dwarf1_debug);
 475
 476       stash = elf_tdata (abfd)->dwarf1_find_line_info
 477         = (struct dwarf1_debug *) bfd_zalloc (abfd, size);
 478
 479       if (! stash)
 480         return FALSE;
 481
 482       msec = bfd_get_section_by_name (abfd, ".debug");
 483       if (! msec)
 484         /* No dwarf1 info.  Note that at this point the stash
 485            has been allocated, but contains zeros, this lets
 486            future calls to this function fail quicker.  */
 487         return FALSE;
 488
 489       size = msec->rawsize ? msec->rawsize : msec->size;
 490       stash->debug_section
 491         = bfd_simple_get_relocated_section_contents (abfd, msec, NULL,
 492                                                      symbols);
 493
 494       if (! stash->debug_section)
 495         return FALSE;
 496
 497       stash->debug_section_end = stash->debug_section + size;
 498       stash->currentDie = stash->debug_section;
 499       stash->abfd = abfd;
 500       stash->syms = symbols;
 501     }
 502
 503   /* A null debug_section indicates that there was no dwarf1 info
 504      or that an error occured while setting up the stash.  */
 505
 506   if (! stash->debug_section)
 507     return FALSE;
 508
 509   /* Look at the previously parsed units to see if any contain
 510      the addr.  */
 511   for (eachUnit = stash->lastUnit; eachUnit; eachUnit = eachUnit->prev)
 512     if (eachUnit->low_pc <= addr && addr < eachUnit->high_pc)
 513       return dwarf1_unit_find_nearest_line (stash, eachUnit, addr,
 514                                             filename_ptr,
 515                                             functionname_ptr,
 516                                             linenumber_ptr);
 517
 518   while (stash->currentDie < stash->debug_section_end)
 519     {
 520       struct die_info aDieInfo;
 521
 522       if (! parse_die (stash->abfd, &aDieInfo, stash->currentDie,
 523                        stash->debug_section_end))
 524         return FALSE;
 525
 526       if (aDieInfo.tag == TAG_compile_unit)
 527         {
 528           struct dwarf1_unit* aUnit
 529             = alloc_dwarf1_unit (stash);
 530           if (!aUnit)
 531             return FALSE;
 532
 533           aUnit->name = aDieInfo.name;
 534           aUnit->low_pc = aDieInfo.low_pc;
 535           aUnit->high_pc = aDieInfo.high_pc;
 536           aUnit->has_stmt_list = aDieInfo.has_stmt_list;
 537           aUnit->stmt_list_offset = aDieInfo.stmt_list_offset;
 538
 539           /* A die has a child if it's followed by a die that is
 540              not it's sibling.  */
 541           if (aDieInfo.sibling
 542               && stash->currentDie + aDieInfo.length
 543                     < stash->debug_section_end
 544               && stash->currentDie + aDieInfo.length
 545                     != stash->debug_section + aDieInfo.sibling)
 546             aUnit->first_child = stash->currentDie + aDieInfo.length;
 547           else
 548             aUnit->first_child = 0;
 549
 550           if (aUnit->low_pc <= addr && addr < aUnit->high_pc)
 551             return dwarf1_unit_find_nearest_line (stash, aUnit, addr,
 552                                                   filename_ptr,
 553                                                   functionname_ptr,
 554                                                   linenumber_ptr);
 555         }
 556
 557       if (aDieInfo.sibling != 0)
 558         stash->currentDie = stash->debug_section + aDieInfo.sibling;
 559       else
 560         stash->currentDie += aDieInfo.length;
 561     }
 562
 563   return FALSE;
 564 }