1 /* DWARF 1 find nearest line (_bfd_dwarf1_find_nearest_line). 2 Copyright (C) 1998-2016 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 aDieInfo->length = bfd_get_32 (abfd, (bfd_byte *) xptr); 193 xptr += 4; 194 if (aDieInfo->length == 0 195 || (this_die + aDieInfo->length) >= aDiePtrEnd) 196 return FALSE; 197 if (aDieInfo->length < 6) 198 { 199 /* Just padding bytes. */ 200 aDieInfo->tag = TAG_padding; 201 return TRUE; 202 } 203 204 /* Then the tag. */ 205 aDieInfo->tag = bfd_get_16 (abfd, (bfd_byte *) xptr); 206 xptr += 2; 207 208 /* Then the attributes. */ 209 while (xptr < (this_die + aDieInfo->length)) 210 { 211 unsigned short attr; 212 213 /* Parse the attribute based on its form. This section 214 must handle all dwarf1 forms, but need only handle the 215 actual attributes that we care about. */ 216 attr = bfd_get_16 (abfd, (bfd_byte *) xptr); 217 xptr += 2; 218 219 switch (FORM_FROM_ATTR (attr)) 220 { 221 case FORM_DATA2: 222 xptr += 2; 223 break; 224 case FORM_DATA4: 225 case FORM_REF: 226 if (attr == AT_sibling) 227 aDieInfo->sibling = bfd_get_32 (abfd, (bfd_byte *) xptr); 228 else if (attr == AT_stmt_list) 229 { 230 aDieInfo->stmt_list_offset = bfd_get_32 (abfd, (bfd_byte *) xptr); 231 aDieInfo->has_stmt_list = 1; 232 } 233 xptr += 4; 234 break; 235 case FORM_DATA8: 236 xptr += 8; 237 break; 238 case FORM_ADDR: 239 if (attr == AT_low_pc) 240 aDieInfo->low_pc = bfd_get_32 (abfd, (bfd_byte *) xptr); 241 else if (attr == AT_high_pc) 242 aDieInfo->high_pc = bfd_get_32 (abfd, (bfd_byte *) xptr); 243 xptr += 4; 244 break; 245 case FORM_BLOCK2: 246 xptr += 2 + bfd_get_16 (abfd, (bfd_byte *) xptr); 247 break; 248 case FORM_BLOCK4: 249 xptr += 4 + bfd_get_32 (abfd, (bfd_byte *) xptr); 250 break; 251 case FORM_STRING: 252 if (attr == AT_name) 253 aDieInfo->name = (char *) xptr; 254 xptr += strlen ((char *) xptr) + 1; 255 break; 256 } 257 } 258 259 return TRUE; 260 } 261 262 /* Parse a dwarf1 line number table for 'aUnit->stmt_list_offset' 263 into 'aUnit->linenumber_table'. Return FALSE if an error 264 occurs; TRUE otherwise. */ 265 266 static bfd_boolean 267 parse_line_table (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit) 268 { 269 bfd_byte *xptr; 270 271 /* Load the ".line" section from the bfd if we haven't already. */ 272 if (stash->line_section == 0) 273 { 274 asection *msec; 275 bfd_size_type size; 276 277 msec = bfd_get_section_by_name (stash->abfd, ".line"); 278 if (! msec) 279 return FALSE; 280 281 size = msec->rawsize ? msec->rawsize : msec->size; 282 stash->line_section 283 = bfd_simple_get_relocated_section_contents 284 (stash->abfd, msec, NULL, stash->syms); 285 286 if (! stash->line_section) 287 return FALSE; 288 289 stash->line_section_end = stash->line_section + size; 290 } 291 292 xptr = stash->line_section + aUnit->stmt_list_offset; 293 if (xptr < stash->line_section_end) 294 { 295 unsigned long eachLine; 296 bfd_byte *tblend; 297 unsigned long base; 298 bfd_size_type amt; 299 300 /* First comes the length. */ 301 tblend = bfd_get_32 (stash->abfd, (bfd_byte *) xptr) + xptr; 302 xptr += 4; 303 304 /* Then the base address for each address in the table. */ 305 base = bfd_get_32 (stash->abfd, (bfd_byte *) xptr); 306 xptr += 4; 307 308 /* How many line entrys? 309 10 = 4 (line number) + 2 (pos in line) + 4 (address in line). */ 310 aUnit->line_count = (tblend - xptr) / 10; 311 312 /* Allocate an array for the entries. */ 313 amt = sizeof (struct linenumber) * aUnit->line_count; 314 aUnit->linenumber_table = (struct linenumber *) bfd_alloc (stash->abfd, 315 amt); 316 if (!aUnit->linenumber_table) 317 return FALSE; 318 319 for (eachLine = 0; eachLine < aUnit->line_count; eachLine++) 320 { 321 /* A line number. */ 322 aUnit->linenumber_table[eachLine].linenumber 323 = bfd_get_32 (stash->abfd, (bfd_byte *) xptr); 324 xptr += 4; 325 326 /* Skip the position within the line. */ 327 xptr += 2; 328 329 /* And finally the address. */ 330 aUnit->linenumber_table[eachLine].addr 331 = base + bfd_get_32 (stash->abfd, (bfd_byte *) xptr); 332 xptr += 4; 333 } 334 } 335 336 return TRUE; 337 } 338 339 /* Parse each function die in a compilation unit 'aUnit'. 340 The first child die of 'aUnit' should be in 'aUnit->first_child', 341 the result is placed in 'aUnit->func_list'. 342 Return FALSE if error; TRUE otherwise. */ 343 344 static bfd_boolean 345 parse_functions_in_unit (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit) 346 { 347 bfd_byte *eachDie; 348 349 if (aUnit->first_child) 350 for (eachDie = aUnit->first_child; 351 eachDie < stash->debug_section_end; 352 ) 353 { 354 struct die_info eachDieInfo; 355 356 if (! parse_die (stash->abfd, &eachDieInfo, eachDie, 357 stash->debug_section_end)) 358 return FALSE; 359 360 if (eachDieInfo.tag == TAG_global_subroutine 361 || eachDieInfo.tag == TAG_subroutine 362 || eachDieInfo.tag == TAG_inlined_subroutine 363 || eachDieInfo.tag == TAG_entry_point) 364 { 365 struct dwarf1_func* aFunc = alloc_dwarf1_func (stash,aUnit); 366 if (!aFunc) 367 return FALSE; 368 369 aFunc->name = eachDieInfo.name; 370 aFunc->low_pc = eachDieInfo.low_pc; 371 aFunc->high_pc = eachDieInfo.high_pc; 372 } 373 374 /* Move to next sibling, if none, end loop */ 375 if (eachDieInfo.sibling) 376 eachDie = stash->debug_section + eachDieInfo.sibling; 377 else 378 break; 379 } 380 381 return TRUE; 382 } 383 384 /* Find the nearest line to 'addr' in 'aUnit'. 385 Return whether we found the line (or a function) without error. */ 386 387 static bfd_boolean 388 dwarf1_unit_find_nearest_line (struct dwarf1_debug* stash, 389 struct dwarf1_unit* aUnit, 390 unsigned long addr, 391 const char **filename_ptr, 392 const char **functionname_ptr, 393 unsigned int *linenumber_ptr) 394 { 395 int line_p = FALSE; 396 int func_p = FALSE; 397 398 if (aUnit->low_pc <= addr && addr < aUnit->high_pc) 399 { 400 if (aUnit->has_stmt_list) 401 { 402 unsigned long i; 403 struct dwarf1_func* eachFunc; 404 405 if (! aUnit->linenumber_table) 406 { 407 if (! parse_line_table (stash, aUnit)) 408 return FALSE; 409 } 410 411 if (! aUnit->func_list) 412 { 413 if (! parse_functions_in_unit (stash, aUnit)) 414 return FALSE; 415 } 416 417 for (i = 0; i < aUnit->line_count; i++) 418 { 419 if (aUnit->linenumber_table[i].addr <= addr 420 && addr < aUnit->linenumber_table[i+1].addr) 421 { 422 *filename_ptr = aUnit->name; 423 *linenumber_ptr = aUnit->linenumber_table[i].linenumber; 424 line_p = TRUE; 425 break; 426 } 427 } 428 429 for (eachFunc = aUnit->func_list; 430 eachFunc; 431 eachFunc = eachFunc->prev) 432 { 433 if (eachFunc->low_pc <= addr 434 && addr < eachFunc->high_pc) 435 { 436 *functionname_ptr = eachFunc->name; 437 func_p = TRUE; 438 break; 439 } 440 } 441 } 442 } 443 444 return line_p || func_p; 445 } 446 447 /* The DWARF 1 version of find_nearest line. 448 Return TRUE if the line is found without error. */ 449 450 bfd_boolean 451 _bfd_dwarf1_find_nearest_line (bfd *abfd, 452 asymbol **symbols, 453 asection *section, 454 bfd_vma offset, 455 const char **filename_ptr, 456 const char **functionname_ptr, 457 unsigned int *linenumber_ptr) 458 { 459 struct dwarf1_debug *stash = elf_tdata (abfd)->dwarf1_find_line_info; 460 461 struct dwarf1_unit* eachUnit; 462 463 /* What address are we looking for? */ 464 unsigned long addr = (unsigned long)(offset + section->vma); 465 466 *filename_ptr = NULL; 467 *functionname_ptr = NULL; 468 *linenumber_ptr = 0; 469 470 if (! stash) 471 { 472 asection *msec; 473 bfd_size_type size = sizeof (struct dwarf1_debug); 474 475 stash = elf_tdata (abfd)->dwarf1_find_line_info 476 = (struct dwarf1_debug *) bfd_zalloc (abfd, size); 477 478 if (! stash) 479 return FALSE; 480 481 msec = bfd_get_section_by_name (abfd, ".debug"); 482 if (! msec) 483 /* No dwarf1 info. Note that at this point the stash 484 has been allocated, but contains zeros, this lets 485 future calls to this function fail quicker. */ 486 return FALSE; 487 488 size = msec->rawsize ? msec->rawsize : msec->size; 489 stash->debug_section 490 = bfd_simple_get_relocated_section_contents (abfd, msec, NULL, 491 symbols); 492 493 if (! stash->debug_section) 494 return FALSE; 495 496 stash->debug_section_end = stash->debug_section + size; 497 stash->currentDie = stash->debug_section; 498 stash->abfd = abfd; 499 stash->syms = symbols; 500 } 501 502 /* A null debug_section indicates that there was no dwarf1 info 503 or that an error occured while setting up the stash. */ 504 505 if (! stash->debug_section) 506 return FALSE; 507 508 /* Look at the previously parsed units to see if any contain 509 the addr. */ 510 for (eachUnit = stash->lastUnit; eachUnit; eachUnit = eachUnit->prev) 511 if (eachUnit->low_pc <= addr && addr < eachUnit->high_pc) 512 return dwarf1_unit_find_nearest_line (stash, eachUnit, addr, 513 filename_ptr, 514 functionname_ptr, 515 linenumber_ptr); 516 517 while (stash->currentDie < stash->debug_section_end) 518 { 519 struct die_info aDieInfo; 520 521 if (! parse_die (stash->abfd, &aDieInfo, stash->currentDie, 522 stash->debug_section_end)) 523 return FALSE; 524 525 if (aDieInfo.tag == TAG_compile_unit) 526 { 527 struct dwarf1_unit* aUnit 528 = alloc_dwarf1_unit (stash); 529 if (!aUnit) 530 return FALSE; 531 532 aUnit->name = aDieInfo.name; 533 aUnit->low_pc = aDieInfo.low_pc; 534 aUnit->high_pc = aDieInfo.high_pc; 535 aUnit->has_stmt_list = aDieInfo.has_stmt_list; 536 aUnit->stmt_list_offset = aDieInfo.stmt_list_offset; 537 538 /* A die has a child if it's followed by a die that is 539 not it's sibling. */ 540 if (aDieInfo.sibling 541 && stash->currentDie + aDieInfo.length 542 < stash->debug_section_end 543 && stash->currentDie + aDieInfo.length 544 != stash->debug_section + aDieInfo.sibling) 545 aUnit->first_child = stash->currentDie + aDieInfo.length; 546 else 547 aUnit->first_child = 0; 548 549 if (aUnit->low_pc <= addr && addr < aUnit->high_pc) 550 return dwarf1_unit_find_nearest_line (stash, aUnit, addr, 551 filename_ptr, 552 functionname_ptr, 553 linenumber_ptr); 554 } 555 556 if (aDieInfo.sibling != 0) 557 stash->currentDie = stash->debug_section + aDieInfo.sibling; 558 else 559 stash->currentDie += aDieInfo.length; 560 } 561 562 return FALSE; 563 } 564