dwarf1.c revision 1.1.1.7
1/* DWARF 1 find nearest line (_bfd_dwarf1_find_nearest_line). 2 Copyright (C) 1998-2022 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 3 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., 51 Franklin Street - Fifth Floor, Boston, 21 MA 02110-1301, USA. */ 22 23#include "sysdep.h" 24#include "bfd.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 32struct dwarf1_debug 33{ 34 /* The bfd we are working with. */ 35 bfd* abfd; 36 37 /* Pointer to the symbol table. */ 38 asymbol** syms; 39 40 /* List of already parsed compilation units. */ 41 struct dwarf1_unit* lastUnit; 42 43 /* The buffer for the .debug section. 44 Zero indicates that the .debug section failed to load. */ 45 bfd_byte *debug_section; 46 47 /* Pointer to the end of the .debug_info section memory buffer. */ 48 bfd_byte *debug_section_end; 49 50 /* The buffer for the .line section. */ 51 bfd_byte *line_section; 52 53 /* End of that buffer. */ 54 bfd_byte *line_section_end; 55 56 /* The current or next unread die within the .debug section. */ 57 bfd_byte *currentDie; 58}; 59 60/* One dwarf1_unit for each parsed compilation unit die. */ 61 62struct dwarf1_unit 63{ 64 /* Linked starting from stash->lastUnit. */ 65 struct dwarf1_unit* prev; 66 67 /* Name of the compilation unit. */ 68 char *name; 69 70 /* The highest and lowest address used in the compilation unit. */ 71 unsigned long low_pc; 72 unsigned long high_pc; 73 74 /* Does this unit have a statement list? */ 75 int has_stmt_list; 76 77 /* If any, the offset of the line number table in the .line section. */ 78 unsigned long stmt_list_offset; 79 80 /* If non-zero, a pointer to the first child of this unit. */ 81 bfd_byte *first_child; 82 83 /* How many line entries? */ 84 unsigned long line_count; 85 86 /* The decoded line number table (line_count entries). */ 87 struct linenumber* linenumber_table; 88 89 /* The list of functions in this unit. */ 90 struct dwarf1_func* func_list; 91}; 92 93/* One dwarf1_func for each parsed function die. */ 94 95struct dwarf1_func 96{ 97 /* Linked starting from aUnit->func_list. */ 98 struct dwarf1_func* prev; 99 100 /* Name of function. */ 101 char* name; 102 103 /* The highest and lowest address used in the compilation unit. */ 104 unsigned long low_pc; 105 unsigned long high_pc; 106}; 107 108/* Used to return info about a parsed die. */ 109struct die_info 110{ 111 unsigned long length; 112 unsigned long sibling; 113 unsigned long low_pc; 114 unsigned long high_pc; 115 unsigned long stmt_list_offset; 116 117 char* name; 118 119 int has_stmt_list; 120 121 unsigned short tag; 122}; 123 124/* Parsed line number information. */ 125struct linenumber 126{ 127 /* First address in the line. */ 128 unsigned long addr; 129 130 /* The line number. */ 131 unsigned long linenumber; 132}; 133 134/* Find the form of an attr, from the attr field. */ 135#define FORM_FROM_ATTR(attr) ((attr) & 0xF) /* Implicitly specified. */ 136 137/* Return a newly allocated dwarf1_unit. It should be cleared and 138 then attached into the 'stash' at 'stash->lastUnit'. */ 139 140static struct dwarf1_unit* 141alloc_dwarf1_unit (struct dwarf1_debug* stash) 142{ 143 size_t amt = sizeof (struct dwarf1_unit); 144 145 struct dwarf1_unit* x = (struct dwarf1_unit *) bfd_zalloc (stash->abfd, amt); 146 if (x) 147 { 148 x->prev = stash->lastUnit; 149 stash->lastUnit = x; 150 } 151 152 return x; 153} 154 155/* Return a newly allocated dwarf1_func. It must be cleared and 156 attached into 'aUnit' at 'aUnit->func_list'. */ 157 158static struct dwarf1_func * 159alloc_dwarf1_func (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit) 160{ 161 size_t amt = sizeof (struct dwarf1_func); 162 163 struct dwarf1_func* x = (struct dwarf1_func *) bfd_zalloc (stash->abfd, amt); 164 if (x) 165 { 166 x->prev = aUnit->func_list; 167 aUnit->func_list = x; 168 } 169 170 return x; 171} 172 173/* parse_die - parse a Dwarf1 die. 174 Parse the die starting at 'aDiePtr' into 'aDieInfo'. 175 'abfd' must be the bfd from which the section that 'aDiePtr' 176 points to was pulled from. 177 178 Return FALSE if the die is invalidly formatted; TRUE otherwise. */ 179 180static bool 181parse_die (bfd * abfd, 182 struct die_info * aDieInfo, 183 bfd_byte * aDiePtr, 184 bfd_byte * aDiePtrEnd) 185{ 186 bfd_byte *this_die = aDiePtr; 187 bfd_byte *xptr = this_die; 188 189 memset (aDieInfo, 0, sizeof (* aDieInfo)); 190 191 /* First comes the length. */ 192 if (xptr + 4 > aDiePtrEnd) 193 return false; 194 aDieInfo->length = bfd_get_32 (abfd, xptr); 195 xptr += 4; 196 if (aDieInfo->length <= 4 197 || (size_t) (aDiePtrEnd - this_die) < aDieInfo->length) 198 return false; 199 aDiePtrEnd = this_die + aDieInfo->length; 200 if (aDieInfo->length < 6) 201 { 202 /* Just padding bytes. */ 203 aDieInfo->tag = TAG_padding; 204 return true; 205 } 206 207 /* Then the tag. */ 208 if (xptr + 2 > aDiePtrEnd) 209 return false; 210 aDieInfo->tag = bfd_get_16 (abfd, xptr); 211 xptr += 2; 212 213 /* Then the attributes. */ 214 while (xptr + 2 <= aDiePtrEnd) 215 { 216 unsigned int block_len; 217 unsigned short attr; 218 219 /* Parse the attribute based on its form. This section 220 must handle all dwarf1 forms, but need only handle the 221 actual attributes that we care about. */ 222 attr = bfd_get_16 (abfd, xptr); 223 xptr += 2; 224 225 switch (FORM_FROM_ATTR (attr)) 226 { 227 case FORM_DATA2: 228 xptr += 2; 229 break; 230 case FORM_DATA4: 231 case FORM_REF: 232 if (xptr + 4 <= aDiePtrEnd) 233 { 234 if (attr == AT_sibling) 235 aDieInfo->sibling = bfd_get_32 (abfd, xptr); 236 else if (attr == AT_stmt_list) 237 { 238 aDieInfo->stmt_list_offset = bfd_get_32 (abfd, xptr); 239 aDieInfo->has_stmt_list = 1; 240 } 241 } 242 xptr += 4; 243 break; 244 case FORM_DATA8: 245 xptr += 8; 246 break; 247 case FORM_ADDR: 248 if (xptr + 4 <= aDiePtrEnd) 249 { 250 if (attr == AT_low_pc) 251 aDieInfo->low_pc = bfd_get_32 (abfd, xptr); 252 else if (attr == AT_high_pc) 253 aDieInfo->high_pc = bfd_get_32 (abfd, xptr); 254 } 255 xptr += 4; 256 break; 257 case FORM_BLOCK2: 258 if (xptr + 2 <= aDiePtrEnd) 259 { 260 block_len = bfd_get_16 (abfd, xptr); 261 if ((size_t) (aDiePtrEnd - xptr) < block_len) 262 return false; 263 xptr += block_len; 264 } 265 xptr += 2; 266 break; 267 case FORM_BLOCK4: 268 if (xptr + 4 <= aDiePtrEnd) 269 { 270 block_len = bfd_get_32 (abfd, xptr); 271 if ((size_t) (aDiePtrEnd - xptr) < block_len) 272 return false; 273 xptr += block_len; 274 } 275 xptr += 4; 276 break; 277 case FORM_STRING: 278 if (attr == AT_name) 279 aDieInfo->name = (char *) xptr; 280 xptr += strnlen ((char *) xptr, aDiePtrEnd - xptr) + 1; 281 break; 282 } 283 } 284 285 return true; 286} 287 288/* Parse a dwarf1 line number table for 'aUnit->stmt_list_offset' 289 into 'aUnit->linenumber_table'. Return FALSE if an error 290 occurs; TRUE otherwise. */ 291 292static bool 293parse_line_table (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit) 294{ 295 bfd_byte *xptr; 296 297 /* Load the ".line" section from the bfd if we haven't already. */ 298 if (stash->line_section == 0) 299 { 300 asection *msec; 301 bfd_size_type size; 302 303 msec = bfd_get_section_by_name (stash->abfd, ".line"); 304 if (! msec) 305 return false; 306 307 size = msec->rawsize ? msec->rawsize : msec->size; 308 stash->line_section 309 = bfd_simple_get_relocated_section_contents 310 (stash->abfd, msec, NULL, stash->syms); 311 312 if (! stash->line_section) 313 return false; 314 315 stash->line_section_end = stash->line_section + size; 316 } 317 318 xptr = stash->line_section + aUnit->stmt_list_offset; 319 if (xptr + 8 <= stash->line_section_end) 320 { 321 unsigned long eachLine; 322 bfd_byte *tblend; 323 unsigned long base; 324 bfd_size_type amt; 325 326 /* First comes the length. */ 327 tblend = bfd_get_32 (stash->abfd, (bfd_byte *) xptr) + xptr; 328 xptr += 4; 329 330 /* Then the base address for each address in the table. */ 331 base = bfd_get_32 (stash->abfd, (bfd_byte *) xptr); 332 xptr += 4; 333 334 /* How many line entrys? 335 10 = 4 (line number) + 2 (pos in line) + 4 (address in line). */ 336 aUnit->line_count = (tblend - xptr) / 10; 337 338 /* Allocate an array for the entries. */ 339 amt = sizeof (struct linenumber) * aUnit->line_count; 340 aUnit->linenumber_table = (struct linenumber *) bfd_alloc (stash->abfd, 341 amt); 342 if (!aUnit->linenumber_table) 343 return false; 344 345 for (eachLine = 0; eachLine < aUnit->line_count; eachLine++) 346 { 347 if (xptr + 10 > stash->line_section_end) 348 { 349 aUnit->line_count = eachLine; 350 break; 351 } 352 /* A line number. */ 353 aUnit->linenumber_table[eachLine].linenumber 354 = bfd_get_32 (stash->abfd, (bfd_byte *) xptr); 355 xptr += 4; 356 357 /* Skip the position within the line. */ 358 xptr += 2; 359 360 /* And finally the address. */ 361 aUnit->linenumber_table[eachLine].addr 362 = base + bfd_get_32 (stash->abfd, (bfd_byte *) xptr); 363 xptr += 4; 364 } 365 } 366 367 return true; 368} 369 370/* Parse each function die in a compilation unit 'aUnit'. 371 The first child die of 'aUnit' should be in 'aUnit->first_child', 372 the result is placed in 'aUnit->func_list'. 373 Return FALSE if error; TRUE otherwise. */ 374 375static bool 376parse_functions_in_unit (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit) 377{ 378 bfd_byte *eachDie; 379 380 if (aUnit->first_child) 381 for (eachDie = aUnit->first_child; 382 eachDie < stash->debug_section_end; 383 ) 384 { 385 struct die_info eachDieInfo; 386 387 if (! parse_die (stash->abfd, &eachDieInfo, eachDie, 388 stash->debug_section_end)) 389 return false; 390 391 if (eachDieInfo.tag == TAG_global_subroutine 392 || eachDieInfo.tag == TAG_subroutine 393 || eachDieInfo.tag == TAG_inlined_subroutine 394 || eachDieInfo.tag == TAG_entry_point) 395 { 396 struct dwarf1_func* aFunc = alloc_dwarf1_func (stash,aUnit); 397 if (!aFunc) 398 return false; 399 400 aFunc->name = eachDieInfo.name; 401 aFunc->low_pc = eachDieInfo.low_pc; 402 aFunc->high_pc = eachDieInfo.high_pc; 403 } 404 405 /* Move to next sibling, if none, end loop */ 406 if (eachDieInfo.sibling) 407 eachDie = stash->debug_section + eachDieInfo.sibling; 408 else 409 break; 410 } 411 412 return true; 413} 414 415/* Find the nearest line to 'addr' in 'aUnit'. 416 Return whether we found the line (or a function) without error. */ 417 418static bool 419dwarf1_unit_find_nearest_line (struct dwarf1_debug* stash, 420 struct dwarf1_unit* aUnit, 421 unsigned long addr, 422 const char **filename_ptr, 423 const char **functionname_ptr, 424 unsigned int *linenumber_ptr) 425{ 426 int line_p = false; 427 int func_p = false; 428 429 if (aUnit->low_pc <= addr && addr < aUnit->high_pc) 430 { 431 if (aUnit->has_stmt_list) 432 { 433 unsigned long i; 434 struct dwarf1_func* eachFunc; 435 436 if (! aUnit->linenumber_table) 437 { 438 if (! parse_line_table (stash, aUnit)) 439 return false; 440 } 441 442 if (! aUnit->func_list) 443 { 444 if (! parse_functions_in_unit (stash, aUnit)) 445 return false; 446 } 447 448 for (i = 0; i < aUnit->line_count; i++) 449 { 450 if (aUnit->linenumber_table[i].addr <= addr 451 && addr < aUnit->linenumber_table[i+1].addr) 452 { 453 *filename_ptr = aUnit->name; 454 *linenumber_ptr = aUnit->linenumber_table[i].linenumber; 455 line_p = true; 456 break; 457 } 458 } 459 460 for (eachFunc = aUnit->func_list; 461 eachFunc; 462 eachFunc = eachFunc->prev) 463 { 464 if (eachFunc->low_pc <= addr 465 && addr < eachFunc->high_pc) 466 { 467 *functionname_ptr = eachFunc->name; 468 func_p = true; 469 break; 470 } 471 } 472 } 473 } 474 475 return line_p || func_p; 476} 477 478/* The DWARF 1 version of find_nearest line. 479 Return TRUE if the line is found without error. */ 480 481bool 482_bfd_dwarf1_find_nearest_line (bfd *abfd, 483 asymbol **symbols, 484 asection *section, 485 bfd_vma offset, 486 const char **filename_ptr, 487 const char **functionname_ptr, 488 unsigned int *linenumber_ptr) 489{ 490 struct dwarf1_debug *stash = elf_tdata (abfd)->dwarf1_find_line_info; 491 492 struct dwarf1_unit* eachUnit; 493 494 /* What address are we looking for? */ 495 unsigned long addr = (unsigned long)(offset + section->vma); 496 497 *filename_ptr = NULL; 498 *functionname_ptr = NULL; 499 *linenumber_ptr = 0; 500 501 if (! stash) 502 { 503 asection *msec; 504 bfd_size_type size = sizeof (struct dwarf1_debug); 505 506 stash = elf_tdata (abfd)->dwarf1_find_line_info 507 = (struct dwarf1_debug *) bfd_zalloc (abfd, size); 508 509 if (! stash) 510 return false; 511 512 msec = bfd_get_section_by_name (abfd, ".debug"); 513 if (! msec) 514 /* No dwarf1 info. Note that at this point the stash 515 has been allocated, but contains zeros, this lets 516 future calls to this function fail quicker. */ 517 return false; 518 519 size = msec->rawsize ? msec->rawsize : msec->size; 520 stash->debug_section 521 = bfd_simple_get_relocated_section_contents (abfd, msec, NULL, 522 symbols); 523 524 if (! stash->debug_section) 525 return false; 526 527 stash->debug_section_end = stash->debug_section + size; 528 stash->currentDie = stash->debug_section; 529 stash->abfd = abfd; 530 stash->syms = symbols; 531 } 532 533 /* A null debug_section indicates that there was no dwarf1 info 534 or that an error occured while setting up the stash. */ 535 536 if (! stash->debug_section) 537 return false; 538 539 /* Look at the previously parsed units to see if any contain 540 the addr. */ 541 for (eachUnit = stash->lastUnit; eachUnit; eachUnit = eachUnit->prev) 542 if (eachUnit->low_pc <= addr && addr < eachUnit->high_pc) 543 return dwarf1_unit_find_nearest_line (stash, eachUnit, addr, 544 filename_ptr, 545 functionname_ptr, 546 linenumber_ptr); 547 548 while (stash->currentDie < stash->debug_section_end) 549 { 550 struct die_info aDieInfo; 551 552 if (! parse_die (stash->abfd, &aDieInfo, stash->currentDie, 553 stash->debug_section_end)) 554 return false; 555 556 if (aDieInfo.tag == TAG_compile_unit) 557 { 558 struct dwarf1_unit* aUnit 559 = alloc_dwarf1_unit (stash); 560 if (!aUnit) 561 return false; 562 563 aUnit->name = aDieInfo.name; 564 aUnit->low_pc = aDieInfo.low_pc; 565 aUnit->high_pc = aDieInfo.high_pc; 566 aUnit->has_stmt_list = aDieInfo.has_stmt_list; 567 aUnit->stmt_list_offset = aDieInfo.stmt_list_offset; 568 569 /* A die has a child if it's followed by a die that is 570 not it's sibling. */ 571 if (aDieInfo.sibling 572 && stash->currentDie + aDieInfo.length 573 < stash->debug_section_end 574 && stash->currentDie + aDieInfo.length 575 != stash->debug_section + aDieInfo.sibling) 576 aUnit->first_child = stash->currentDie + aDieInfo.length; 577 else 578 aUnit->first_child = 0; 579 580 if (aUnit->low_pc <= addr && addr < aUnit->high_pc) 581 return dwarf1_unit_find_nearest_line (stash, aUnit, addr, 582 filename_ptr, 583 functionname_ptr, 584 linenumber_ptr); 585 } 586 587 if (aDieInfo.sibling != 0) 588 stash->currentDie = stash->debug_section + aDieInfo.sibling; 589 else 590 stash->currentDie += aDieInfo.length; 591 } 592 593 return false; 594} 595