1 /* DWARF 1 find nearest line (_bfd_dwarf1_find_nearest_line). 2 Copyright (C) 1998-2020 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 32 struct 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 62 struct 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 95 struct 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. */ 109 struct 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. */ 125 struct 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'. */ 139 140 static struct dwarf1_unit* 141 alloc_dwarf1_unit (struct dwarf1_debug* stash) 142 { 143 bfd_size_type 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'. */ 157 158 static struct dwarf1_func * 159 alloc_dwarf1_func (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit) 160 { 161 bfd_size_type 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. */ 179 180 static bfd_boolean 181 parse_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 == 0 197 || this_die + aDieInfo->length > aDiePtrEnd) 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 (xptr + block_len > aDiePtrEnd 262 || xptr + block_len < xptr) 263 return FALSE; 264 xptr += block_len; 265 } 266 xptr += 2; 267 break; 268 case FORM_BLOCK4: 269 if (xptr + 4 <= aDiePtrEnd) 270 { 271 block_len = bfd_get_32 (abfd, xptr); 272 if (xptr + block_len > aDiePtrEnd 273 || xptr + block_len < xptr) 274 return FALSE; 275 xptr += block_len; 276 } 277 xptr += 4; 278 break; 279 case FORM_STRING: 280 if (attr == AT_name) 281 aDieInfo->name = (char *) xptr; 282 xptr += strnlen ((char *) xptr, aDiePtrEnd - xptr) + 1; 283 break; 284 } 285 } 286 287 return TRUE; 288 } 289 290 /* Parse a dwarf1 line number table for 'aUnit->stmt_list_offset' 291 into 'aUnit->linenumber_table'. Return FALSE if an error 292 occurs; TRUE otherwise. */ 293 294 static bfd_boolean 295 parse_line_table (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit) 296 { 297 bfd_byte *xptr; 298 299 /* Load the ".line" section from the bfd if we haven't already. */ 300 if (stash->line_section == 0) 301 { 302 asection *msec; 303 bfd_size_type size; 304 305 msec = bfd_get_section_by_name (stash->abfd, ".line"); 306 if (! msec) 307 return FALSE; 308 309 size = msec->rawsize ? msec->rawsize : msec->size; 310 stash->line_section 311 = bfd_simple_get_relocated_section_contents 312 (stash->abfd, msec, NULL, stash->syms); 313 314 if (! stash->line_section) 315 return FALSE; 316 317 stash->line_section_end = stash->line_section + size; 318 } 319 320 xptr = stash->line_section + aUnit->stmt_list_offset; 321 if (xptr + 8 <= stash->line_section_end) 322 { 323 unsigned long eachLine; 324 bfd_byte *tblend; 325 unsigned long base; 326 bfd_size_type amt; 327 328 /* First comes the length. */ 329 tblend = bfd_get_32 (stash->abfd, (bfd_byte *) xptr) + xptr; 330 xptr += 4; 331 332 /* Then the base address for each address in the table. */ 333 base = bfd_get_32 (stash->abfd, (bfd_byte *) xptr); 334 xptr += 4; 335 336 /* How many line entrys? 337 10 = 4 (line number) + 2 (pos in line) + 4 (address in line). */ 338 aUnit->line_count = (tblend - xptr) / 10; 339 340 /* Allocate an array for the entries. */ 341 amt = sizeof (struct linenumber) * aUnit->line_count; 342 aUnit->linenumber_table = (struct linenumber *) bfd_alloc (stash->abfd, 343 amt); 344 if (!aUnit->linenumber_table) 345 return FALSE; 346 347 for (eachLine = 0; eachLine < aUnit->line_count; eachLine++) 348 { 349 if (xptr + 10 > stash->line_section_end) 350 { 351 aUnit->line_count = eachLine; 352 break; 353 } 354 /* A line number. */ 355 aUnit->linenumber_table[eachLine].linenumber 356 = bfd_get_32 (stash->abfd, (bfd_byte *) xptr); 357 xptr += 4; 358 359 /* Skip the position within the line. */ 360 xptr += 2; 361 362 /* And finally the address. */ 363 aUnit->linenumber_table[eachLine].addr 364 = base + bfd_get_32 (stash->abfd, (bfd_byte *) xptr); 365 xptr += 4; 366 } 367 } 368 369 return TRUE; 370 } 371 372 /* Parse each function die in a compilation unit 'aUnit'. 373 The first child die of 'aUnit' should be in 'aUnit->first_child', 374 the result is placed in 'aUnit->func_list'. 375 Return FALSE if error; TRUE otherwise. */ 376 377 static bfd_boolean 378 parse_functions_in_unit (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit) 379 { 380 bfd_byte *eachDie; 381 382 if (aUnit->first_child) 383 for (eachDie = aUnit->first_child; 384 eachDie < stash->debug_section_end; 385 ) 386 { 387 struct die_info eachDieInfo; 388 389 if (! parse_die (stash->abfd, &eachDieInfo, eachDie, 390 stash->debug_section_end)) 391 return FALSE; 392 393 if (eachDieInfo.tag == TAG_global_subroutine 394 || eachDieInfo.tag == TAG_subroutine 395 || eachDieInfo.tag == TAG_inlined_subroutine 396 || eachDieInfo.tag == TAG_entry_point) 397 { 398 struct dwarf1_func* aFunc = alloc_dwarf1_func (stash,aUnit); 399 if (!aFunc) 400 return FALSE; 401 402 aFunc->name = eachDieInfo.name; 403 aFunc->low_pc = eachDieInfo.low_pc; 404 aFunc->high_pc = eachDieInfo.high_pc; 405 } 406 407 /* Move to next sibling, if none, end loop */ 408 if (eachDieInfo.sibling) 409 eachDie = stash->debug_section + eachDieInfo.sibling; 410 else 411 break; 412 } 413 414 return TRUE; 415 } 416 417 /* Find the nearest line to 'addr' in 'aUnit'. 418 Return whether we found the line (or a function) without error. */ 419 420 static bfd_boolean 421 dwarf1_unit_find_nearest_line (struct dwarf1_debug* stash, 422 struct dwarf1_unit* aUnit, 423 unsigned long addr, 424 const char **filename_ptr, 425 const char **functionname_ptr, 426 unsigned int *linenumber_ptr) 427 { 428 int line_p = FALSE; 429 int func_p = FALSE; 430 431 if (aUnit->low_pc <= addr && addr < aUnit->high_pc) 432 { 433 if (aUnit->has_stmt_list) 434 { 435 unsigned long i; 436 struct dwarf1_func* eachFunc; 437 438 if (! aUnit->linenumber_table) 439 { 440 if (! parse_line_table (stash, aUnit)) 441 return FALSE; 442 } 443 444 if (! aUnit->func_list) 445 { 446 if (! parse_functions_in_unit (stash, aUnit)) 447 return FALSE; 448 } 449 450 for (i = 0; i < aUnit->line_count; i++) 451 { 452 if (aUnit->linenumber_table[i].addr <= addr 453 && addr < aUnit->linenumber_table[i+1].addr) 454 { 455 *filename_ptr = aUnit->name; 456 *linenumber_ptr = aUnit->linenumber_table[i].linenumber; 457 line_p = TRUE; 458 break; 459 } 460 } 461 462 for (eachFunc = aUnit->func_list; 463 eachFunc; 464 eachFunc = eachFunc->prev) 465 { 466 if (eachFunc->low_pc <= addr 467 && addr < eachFunc->high_pc) 468 { 469 *functionname_ptr = eachFunc->name; 470 func_p = TRUE; 471 break; 472 } 473 } 474 } 475 } 476 477 return line_p || func_p; 478 } 479 480 /* The DWARF 1 version of find_nearest line. 481 Return TRUE if the line is found without error. */ 482 483 bfd_boolean 484 _bfd_dwarf1_find_nearest_line (bfd *abfd, 485 asymbol **symbols, 486 asection *section, 487 bfd_vma offset, 488 const char **filename_ptr, 489 const char **functionname_ptr, 490 unsigned int *linenumber_ptr) 491 { 492 struct dwarf1_debug *stash = elf_tdata (abfd)->dwarf1_find_line_info; 493 494 struct dwarf1_unit* eachUnit; 495 496 /* What address are we looking for? */ 497 unsigned long addr = (unsigned long)(offset + section->vma); 498 499 *filename_ptr = NULL; 500 *functionname_ptr = NULL; 501 *linenumber_ptr = 0; 502 503 if (! stash) 504 { 505 asection *msec; 506 bfd_size_type size = sizeof (struct dwarf1_debug); 507 508 stash = elf_tdata (abfd)->dwarf1_find_line_info 509 = (struct dwarf1_debug *) bfd_zalloc (abfd, size); 510 511 if (! stash) 512 return FALSE; 513 514 msec = bfd_get_section_by_name (abfd, ".debug"); 515 if (! msec) 516 /* No dwarf1 info. Note that at this point the stash 517 has been allocated, but contains zeros, this lets 518 future calls to this function fail quicker. */ 519 return FALSE; 520 521 size = msec->rawsize ? msec->rawsize : msec->size; 522 stash->debug_section 523 = bfd_simple_get_relocated_section_contents (abfd, msec, NULL, 524 symbols); 525 526 if (! stash->debug_section) 527 return FALSE; 528 529 stash->debug_section_end = stash->debug_section + size; 530 stash->currentDie = stash->debug_section; 531 stash->abfd = abfd; 532 stash->syms = symbols; 533 } 534 535 /* A null debug_section indicates that there was no dwarf1 info 536 or that an error occured while setting up the stash. */ 537 538 if (! stash->debug_section) 539 return FALSE; 540 541 /* Look at the previously parsed units to see if any contain 542 the addr. */ 543 for (eachUnit = stash->lastUnit; eachUnit; eachUnit = eachUnit->prev) 544 if (eachUnit->low_pc <= addr && addr < eachUnit->high_pc) 545 return dwarf1_unit_find_nearest_line (stash, eachUnit, addr, 546 filename_ptr, 547 functionname_ptr, 548 linenumber_ptr); 549 550 while (stash->currentDie < stash->debug_section_end) 551 { 552 struct die_info aDieInfo; 553 554 if (! parse_die (stash->abfd, &aDieInfo, stash->currentDie, 555 stash->debug_section_end)) 556 return FALSE; 557 558 if (aDieInfo.tag == TAG_compile_unit) 559 { 560 struct dwarf1_unit* aUnit 561 = alloc_dwarf1_unit (stash); 562 if (!aUnit) 563 return FALSE; 564 565 aUnit->name = aDieInfo.name; 566 aUnit->low_pc = aDieInfo.low_pc; 567 aUnit->high_pc = aDieInfo.high_pc; 568 aUnit->has_stmt_list = aDieInfo.has_stmt_list; 569 aUnit->stmt_list_offset = aDieInfo.stmt_list_offset; 570 571 /* A die has a child if it's followed by a die that is 572 not it's sibling. */ 573 if (aDieInfo.sibling 574 && stash->currentDie + aDieInfo.length 575 < stash->debug_section_end 576 && stash->currentDie + aDieInfo.length 577 != stash->debug_section + aDieInfo.sibling) 578 aUnit->first_child = stash->currentDie + aDieInfo.length; 579 else 580 aUnit->first_child = 0; 581 582 if (aUnit->low_pc <= addr && addr < aUnit->high_pc) 583 return dwarf1_unit_find_nearest_line (stash, aUnit, addr, 584 filename_ptr, 585 functionname_ptr, 586 linenumber_ptr); 587 } 588 589 if (aDieInfo.sibling != 0) 590 stash->currentDie = stash->debug_section + aDieInfo.sibling; 591 else 592 stash->currentDie += aDieInfo.length; 593 } 594 595 return FALSE; 596 } 597