1/* GDB routines for manipulating the minimal symbol tables. 2 Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 3 2002, 2003, 2004, 2007 Free Software Foundation, Inc. 4 Contributed by Cygnus Support, using pieces from other GDB modules. 5 6 This file is part of GDB. 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 11 (at your option) any later version. 12 13 This program is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU 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, see <http://www.gnu.org/licenses/>. */ 20 21 22/* This file contains support routines for creating, manipulating, and 23 destroying minimal symbol tables. 24 25 Minimal symbol tables are used to hold some very basic information about 26 all defined global symbols (text, data, bss, abs, etc). The only two 27 required pieces of information are the symbol's name and the address 28 associated with that symbol. 29 30 In many cases, even if a file was compiled with no special options for 31 debugging at all, as long as was not stripped it will contain sufficient 32 information to build useful minimal symbol tables using this structure. 33 34 Even when a file contains enough debugging information to build a full 35 symbol table, these minimal symbols are still useful for quickly mapping 36 between names and addresses, and vice versa. They are also sometimes used 37 to figure out what full symbol table entries need to be read in. */ 38 39 40#include "defs.h" 41#include <ctype.h> 42#include "gdb_string.h" 43#include "symtab.h" 44#include "bfd.h" 45#include "symfile.h" 46#include "objfiles.h" 47#include "demangle.h" 48#include "value.h" 49#include "cp-abi.h" 50 51/* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE. 52 At the end, copy them all into one newly allocated location on an objfile's 53 symbol obstack. */ 54 55#define BUNCH_SIZE 127 56 57struct msym_bunch 58 { 59 struct msym_bunch *next; 60 struct minimal_symbol contents[BUNCH_SIZE]; 61 }; 62 63/* Bunch currently being filled up. 64 The next field points to chain of filled bunches. */ 65 66static struct msym_bunch *msym_bunch; 67 68/* Number of slots filled in current bunch. */ 69 70static int msym_bunch_index; 71 72/* Total number of minimal symbols recorded so far for the objfile. */ 73 74static int msym_count; 75 76/* Compute a hash code based using the same criteria as `strcmp_iw'. */ 77 78unsigned int 79msymbol_hash_iw (const char *string) 80{ 81 unsigned int hash = 0; 82 while (*string && *string != '(') 83 { 84 while (isspace (*string)) 85 ++string; 86 if (*string && *string != '(') 87 { 88 hash = hash * 67 + *string - 113; 89 ++string; 90 } 91 } 92 return hash; 93} 94 95/* Compute a hash code for a string. */ 96 97unsigned int 98msymbol_hash (const char *string) 99{ 100 unsigned int hash = 0; 101 for (; *string; ++string) 102 hash = hash * 67 + *string - 113; 103 return hash; 104} 105 106/* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */ 107void 108add_minsym_to_hash_table (struct minimal_symbol *sym, 109 struct minimal_symbol **table) 110{ 111 if (sym->hash_next == NULL) 112 { 113 unsigned int hash 114 = msymbol_hash (SYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE; 115 sym->hash_next = table[hash]; 116 table[hash] = sym; 117 } 118} 119 120/* Add the minimal symbol SYM to an objfile's minsym demangled hash table, 121 TABLE. */ 122static void 123add_minsym_to_demangled_hash_table (struct minimal_symbol *sym, 124 struct minimal_symbol **table) 125{ 126 if (sym->demangled_hash_next == NULL) 127 { 128 unsigned int hash = msymbol_hash_iw (SYMBOL_DEMANGLED_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE; 129 sym->demangled_hash_next = table[hash]; 130 table[hash] = sym; 131 } 132} 133 134 135/* Look through all the current minimal symbol tables and find the 136 first minimal symbol that matches NAME. If OBJF is non-NULL, limit 137 the search to that objfile. If SFILE is non-NULL, the only file-scope 138 symbols considered will be from that source file (global symbols are 139 still preferred). Returns a pointer to the minimal symbol that 140 matches, or NULL if no match is found. 141 142 Note: One instance where there may be duplicate minimal symbols with 143 the same name is when the symbol tables for a shared library and the 144 symbol tables for an executable contain global symbols with the same 145 names (the dynamic linker deals with the duplication). 146 147 It's also possible to have minimal symbols with different mangled 148 names, but identical demangled names. For example, the GNU C++ v3 149 ABI requires the generation of two (or perhaps three) copies of 150 constructor functions --- "in-charge", "not-in-charge", and 151 "allocate" copies; destructors may be duplicated as well. 152 Obviously, there must be distinct mangled names for each of these, 153 but the demangled names are all the same: S::S or S::~S. */ 154 155struct minimal_symbol * 156lookup_minimal_symbol (const char *name, const char *sfile, 157 struct objfile *objf) 158{ 159 struct objfile *objfile; 160 struct minimal_symbol *msymbol; 161 struct minimal_symbol *found_symbol = NULL; 162 struct minimal_symbol *found_file_symbol = NULL; 163 struct minimal_symbol *trampoline_symbol = NULL; 164 165 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE; 166 unsigned int dem_hash = msymbol_hash_iw (name) % MINIMAL_SYMBOL_HASH_SIZE; 167 168#ifdef SOFUN_ADDRESS_MAYBE_MISSING 169 if (sfile != NULL) 170 { 171 char *p = strrchr (sfile, '/'); 172 if (p != NULL) 173 sfile = p + 1; 174 } 175#endif 176 177 for (objfile = object_files; 178 objfile != NULL && found_symbol == NULL; 179 objfile = objfile->next) 180 { 181 if (objf == NULL || objf == objfile) 182 { 183 /* Do two passes: the first over the ordinary hash table, 184 and the second over the demangled hash table. */ 185 int pass; 186 187 for (pass = 1; pass <= 2 && found_symbol == NULL; pass++) 188 { 189 /* Select hash list according to pass. */ 190 if (pass == 1) 191 msymbol = objfile->msymbol_hash[hash]; 192 else 193 msymbol = objfile->msymbol_demangled_hash[dem_hash]; 194 195 while (msymbol != NULL && found_symbol == NULL) 196 { 197 /* FIXME: carlton/2003-02-27: This is an unholy 198 mixture of linkage names and natural names. If 199 you want to test the linkage names with strcmp, 200 do that. If you want to test the natural names 201 with strcmp_iw, use SYMBOL_MATCHES_NATURAL_NAME. */ 202 if (strcmp (DEPRECATED_SYMBOL_NAME (msymbol), (name)) == 0 203 || (SYMBOL_DEMANGLED_NAME (msymbol) != NULL 204 && strcmp_iw (SYMBOL_DEMANGLED_NAME (msymbol), 205 (name)) == 0)) 206 { 207 switch (MSYMBOL_TYPE (msymbol)) 208 { 209 case mst_file_text: 210 case mst_file_data: 211 case mst_file_bss: 212#ifdef SOFUN_ADDRESS_MAYBE_MISSING 213 if (sfile == NULL 214 || strcmp (msymbol->filename, sfile) == 0) 215 found_file_symbol = msymbol; 216#else 217 /* We have neither the ability nor the need to 218 deal with the SFILE parameter. If we find 219 more than one symbol, just return the latest 220 one (the user can't expect useful behavior in 221 that case). */ 222 found_file_symbol = msymbol; 223#endif 224 break; 225 226 case mst_solib_trampoline: 227 228 /* If a trampoline symbol is found, we prefer to 229 keep looking for the *real* symbol. If the 230 actual symbol is not found, then we'll use the 231 trampoline entry. */ 232 if (trampoline_symbol == NULL) 233 trampoline_symbol = msymbol; 234 break; 235 236 case mst_unknown: 237 default: 238 found_symbol = msymbol; 239 break; 240 } 241 } 242 243 /* Find the next symbol on the hash chain. */ 244 if (pass == 1) 245 msymbol = msymbol->hash_next; 246 else 247 msymbol = msymbol->demangled_hash_next; 248 } 249 } 250 } 251 } 252 /* External symbols are best. */ 253 if (found_symbol) 254 return found_symbol; 255 256 /* File-local symbols are next best. */ 257 if (found_file_symbol) 258 return found_file_symbol; 259 260 /* Symbols for shared library trampolines are next best. */ 261 if (trampoline_symbol) 262 return trampoline_symbol; 263 264 return NULL; 265} 266 267/* Look through all the current minimal symbol tables and find the 268 first minimal symbol that matches NAME and has text type. If OBJF 269 is non-NULL, limit the search to that objfile. Returns a pointer 270 to the minimal symbol that matches, or NULL if no match is found. 271 272 This function only searches the mangled (linkage) names. */ 273 274struct minimal_symbol * 275lookup_minimal_symbol_text (const char *name, struct objfile *objf) 276{ 277 struct objfile *objfile; 278 struct minimal_symbol *msymbol; 279 struct minimal_symbol *found_symbol = NULL; 280 struct minimal_symbol *found_file_symbol = NULL; 281 282 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE; 283 284 for (objfile = object_files; 285 objfile != NULL && found_symbol == NULL; 286 objfile = objfile->next) 287 { 288 if (objf == NULL || objf == objfile) 289 { 290 for (msymbol = objfile->msymbol_hash[hash]; 291 msymbol != NULL && found_symbol == NULL; 292 msymbol = msymbol->hash_next) 293 { 294 if (strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0 && 295 (MSYMBOL_TYPE (msymbol) == mst_text || 296 MSYMBOL_TYPE (msymbol) == mst_file_text)) 297 { 298 switch (MSYMBOL_TYPE (msymbol)) 299 { 300 case mst_file_text: 301 found_file_symbol = msymbol; 302 break; 303 default: 304 found_symbol = msymbol; 305 break; 306 } 307 } 308 } 309 } 310 } 311 /* External symbols are best. */ 312 if (found_symbol) 313 return found_symbol; 314 315 /* File-local symbols are next best. */ 316 if (found_file_symbol) 317 return found_file_symbol; 318 319 return NULL; 320} 321 322/* Look through all the current minimal symbol tables and find the 323 first minimal symbol that matches NAME and is a solib trampoline. 324 If OBJF is non-NULL, limit the search to that objfile. Returns a 325 pointer to the minimal symbol that matches, or NULL if no match is 326 found. 327 328 This function only searches the mangled (linkage) names. */ 329 330struct minimal_symbol * 331lookup_minimal_symbol_solib_trampoline (const char *name, 332 struct objfile *objf) 333{ 334 struct objfile *objfile; 335 struct minimal_symbol *msymbol; 336 struct minimal_symbol *found_symbol = NULL; 337 338 unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE; 339 340 for (objfile = object_files; 341 objfile != NULL && found_symbol == NULL; 342 objfile = objfile->next) 343 { 344 if (objf == NULL || objf == objfile) 345 { 346 for (msymbol = objfile->msymbol_hash[hash]; 347 msymbol != NULL && found_symbol == NULL; 348 msymbol = msymbol->hash_next) 349 { 350 if (strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0 && 351 MSYMBOL_TYPE (msymbol) == mst_solib_trampoline) 352 return msymbol; 353 } 354 } 355 } 356 357 return NULL; 358} 359 360/* Search through the minimal symbol table for each objfile and find 361 the symbol whose address is the largest address that is still less 362 than or equal to PC, and matches SECTION (if non-NULL). Returns a 363 pointer to the minimal symbol if such a symbol is found, or NULL if 364 PC is not in a suitable range. Note that we need to look through 365 ALL the minimal symbol tables before deciding on the symbol that 366 comes closest to the specified PC. This is because objfiles can 367 overlap, for example objfile A has .text at 0x100 and .data at 368 0x40000 and objfile B has .text at 0x234 and .data at 0x40048. */ 369 370struct minimal_symbol * 371lookup_minimal_symbol_by_pc_section (CORE_ADDR pc, asection *section) 372{ 373 int lo; 374 int hi; 375 int new; 376 struct objfile *objfile; 377 struct minimal_symbol *msymbol; 378 struct minimal_symbol *best_symbol = NULL; 379 struct obj_section *pc_section; 380 381 /* PC has to be in a known section. This ensures that anything 382 beyond the end of the last segment doesn't appear to be part of 383 the last function in the last segment. */ 384 pc_section = find_pc_section (pc); 385 if (pc_section == NULL) 386 return NULL; 387 388 /* We can not require the symbol found to be in pc_section, because 389 e.g. IRIX 6.5 mdebug relies on this code returning an absolute 390 symbol - but find_pc_section won't return an absolute section and 391 hence the code below would skip over absolute symbols. We can 392 still take advantage of the call to find_pc_section, though - the 393 object file still must match. In case we have separate debug 394 files, search both the file and its separate debug file. There's 395 no telling which one will have the minimal symbols. */ 396 397 objfile = pc_section->objfile; 398 if (objfile->separate_debug_objfile) 399 objfile = objfile->separate_debug_objfile; 400 401 for (; objfile != NULL; objfile = objfile->separate_debug_objfile_backlink) 402 { 403 /* If this objfile has a minimal symbol table, go search it using 404 a binary search. Note that a minimal symbol table always consists 405 of at least two symbols, a "real" symbol and the terminating 406 "null symbol". If there are no real symbols, then there is no 407 minimal symbol table at all. */ 408 409 if (objfile->minimal_symbol_count > 0) 410 { 411 int best_zero_sized = -1; 412 413 msymbol = objfile->msymbols; 414 lo = 0; 415 hi = objfile->minimal_symbol_count - 1; 416 417 /* This code assumes that the minimal symbols are sorted by 418 ascending address values. If the pc value is greater than or 419 equal to the first symbol's address, then some symbol in this 420 minimal symbol table is a suitable candidate for being the 421 "best" symbol. This includes the last real symbol, for cases 422 where the pc value is larger than any address in this vector. 423 424 By iterating until the address associated with the current 425 hi index (the endpoint of the test interval) is less than 426 or equal to the desired pc value, we accomplish two things: 427 (1) the case where the pc value is larger than any minimal 428 symbol address is trivially solved, (2) the address associated 429 with the hi index is always the one we want when the interation 430 terminates. In essence, we are iterating the test interval 431 down until the pc value is pushed out of it from the high end. 432 433 Warning: this code is trickier than it would appear at first. */ 434 435 /* Should also require that pc is <= end of objfile. FIXME! */ 436 if (pc >= SYMBOL_VALUE_ADDRESS (&msymbol[lo])) 437 { 438 while (SYMBOL_VALUE_ADDRESS (&msymbol[hi]) > pc) 439 { 440 /* pc is still strictly less than highest address */ 441 /* Note "new" will always be >= lo */ 442 new = (lo + hi) / 2; 443 if ((SYMBOL_VALUE_ADDRESS (&msymbol[new]) >= pc) || 444 (lo == new)) 445 { 446 hi = new; 447 } 448 else 449 { 450 lo = new; 451 } 452 } 453 454 /* If we have multiple symbols at the same address, we want 455 hi to point to the last one. That way we can find the 456 right symbol if it has an index greater than hi. */ 457 while (hi < objfile->minimal_symbol_count - 1 458 && (SYMBOL_VALUE_ADDRESS (&msymbol[hi]) 459 == SYMBOL_VALUE_ADDRESS (&msymbol[hi + 1]))) 460 hi++; 461 462 /* Skip various undesirable symbols. */ 463 while (hi >= 0) 464 { 465 /* Skip any absolute symbols. This is apparently 466 what adb and dbx do, and is needed for the CM-5. 467 There are two known possible problems: (1) on 468 ELF, apparently end, edata, etc. are absolute. 469 Not sure ignoring them here is a big deal, but if 470 we want to use them, the fix would go in 471 elfread.c. (2) I think shared library entry 472 points on the NeXT are absolute. If we want 473 special handling for this it probably should be 474 triggered by a special mst_abs_or_lib or some 475 such. */ 476 477 if (msymbol[hi].type == mst_abs) 478 { 479 hi--; 480 continue; 481 } 482 483 /* If SECTION was specified, skip any symbol from 484 wrong section. */ 485 if (section 486 /* Some types of debug info, such as COFF, 487 don't fill the bfd_section member, so don't 488 throw away symbols on those platforms. */ 489 && SYMBOL_BFD_SECTION (&msymbol[hi]) != NULL 490 && (!matching_bfd_sections 491 (SYMBOL_BFD_SECTION (&msymbol[hi]), section))) 492 { 493 hi--; 494 continue; 495 } 496 497 /* If the minimal symbol has a zero size, save it 498 but keep scanning backwards looking for one with 499 a non-zero size. A zero size may mean that the 500 symbol isn't an object or function (e.g. a 501 label), or it may just mean that the size was not 502 specified. */ 503 if (MSYMBOL_SIZE (&msymbol[hi]) == 0 504 && best_zero_sized == -1) 505 { 506 best_zero_sized = hi; 507 hi--; 508 continue; 509 } 510 511 /* If we are past the end of the current symbol, try 512 the previous symbol if it has a larger overlapping 513 size. This happens on i686-pc-linux-gnu with glibc; 514 the nocancel variants of system calls are inside 515 the cancellable variants, but both have sizes. */ 516 if (hi > 0 517 && MSYMBOL_SIZE (&msymbol[hi]) != 0 518 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi]) 519 + MSYMBOL_SIZE (&msymbol[hi])) 520 && pc < (SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1]) 521 + MSYMBOL_SIZE (&msymbol[hi - 1]))) 522 { 523 hi--; 524 continue; 525 } 526 527 /* Otherwise, this symbol must be as good as we're going 528 to get. */ 529 break; 530 } 531 532 /* If HI has a zero size, and best_zero_sized is set, 533 then we had two or more zero-sized symbols; prefer 534 the first one we found (which may have a higher 535 address). Also, if we ran off the end, be sure 536 to back up. */ 537 if (best_zero_sized != -1 538 && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0)) 539 hi = best_zero_sized; 540 541 /* If the minimal symbol has a non-zero size, and this 542 PC appears to be outside the symbol's contents, then 543 refuse to use this symbol. If we found a zero-sized 544 symbol with an address greater than this symbol's, 545 use that instead. We assume that if symbols have 546 specified sizes, they do not overlap. */ 547 548 if (hi >= 0 549 && MSYMBOL_SIZE (&msymbol[hi]) != 0 550 && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi]) 551 + MSYMBOL_SIZE (&msymbol[hi]))) 552 { 553 if (best_zero_sized != -1) 554 hi = best_zero_sized; 555 else 556 /* Go on to the next object file. */ 557 continue; 558 } 559 560 /* The minimal symbol indexed by hi now is the best one in this 561 objfile's minimal symbol table. See if it is the best one 562 overall. */ 563 564 if (hi >= 0 565 && ((best_symbol == NULL) || 566 (SYMBOL_VALUE_ADDRESS (best_symbol) < 567 SYMBOL_VALUE_ADDRESS (&msymbol[hi])))) 568 { 569 best_symbol = &msymbol[hi]; 570 } 571 } 572 } 573 } 574 return (best_symbol); 575} 576 577/* Backward compatibility: search through the minimal symbol table 578 for a matching PC (no section given) */ 579 580struct minimal_symbol * 581lookup_minimal_symbol_by_pc (CORE_ADDR pc) 582{ 583 /* NOTE: cagney/2004-01-27: This was using find_pc_mapped_section to 584 force the section but that (well unless you're doing overlay 585 debugging) always returns NULL making the call somewhat useless. */ 586 struct obj_section *section = find_pc_section (pc); 587 if (section == NULL) 588 return NULL; 589 return lookup_minimal_symbol_by_pc_section (pc, section->the_bfd_section); 590} 591 592 593/* Return leading symbol character for a BFD. If BFD is NULL, 594 return the leading symbol character from the main objfile. */ 595 596static int get_symbol_leading_char (bfd *); 597 598static int 599get_symbol_leading_char (bfd *abfd) 600{ 601 if (abfd != NULL) 602 return bfd_get_symbol_leading_char (abfd); 603 if (symfile_objfile != NULL && symfile_objfile->obfd != NULL) 604 return bfd_get_symbol_leading_char (symfile_objfile->obfd); 605 return 0; 606} 607 608/* Prepare to start collecting minimal symbols. Note that presetting 609 msym_bunch_index to BUNCH_SIZE causes the first call to save a minimal 610 symbol to allocate the memory for the first bunch. */ 611 612void 613init_minimal_symbol_collection (void) 614{ 615 msym_count = 0; 616 msym_bunch = NULL; 617 msym_bunch_index = BUNCH_SIZE; 618} 619 620void 621prim_record_minimal_symbol (const char *name, CORE_ADDR address, 622 enum minimal_symbol_type ms_type, 623 struct objfile *objfile) 624{ 625 int section; 626 627 switch (ms_type) 628 { 629 case mst_text: 630 case mst_file_text: 631 case mst_solib_trampoline: 632 section = SECT_OFF_TEXT (objfile); 633 break; 634 case mst_data: 635 case mst_file_data: 636 section = SECT_OFF_DATA (objfile); 637 break; 638 case mst_bss: 639 case mst_file_bss: 640 section = SECT_OFF_BSS (objfile); 641 break; 642 default: 643 section = -1; 644 } 645 646 prim_record_minimal_symbol_and_info (name, address, ms_type, 647 NULL, section, NULL, objfile); 648} 649 650/* Record a minimal symbol in the msym bunches. Returns the symbol 651 newly created. */ 652 653struct minimal_symbol * 654prim_record_minimal_symbol_and_info (const char *name, CORE_ADDR address, 655 enum minimal_symbol_type ms_type, 656 char *info, int section, 657 asection *bfd_section, 658 struct objfile *objfile) 659{ 660 struct msym_bunch *new; 661 struct minimal_symbol *msymbol; 662 663 /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into 664 the minimal symbols, because if there is also another symbol 665 at the same address (e.g. the first function of the file), 666 lookup_minimal_symbol_by_pc would have no way of getting the 667 right one. */ 668 if (ms_type == mst_file_text && name[0] == 'g' 669 && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0 670 || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0)) 671 return (NULL); 672 673 /* It's safe to strip the leading char here once, since the name 674 is also stored stripped in the minimal symbol table. */ 675 if (name[0] == get_symbol_leading_char (objfile->obfd)) 676 ++name; 677 678 if (ms_type == mst_file_text && strncmp (name, "__gnu_compiled", 14) == 0) 679 return (NULL); 680 681 if (msym_bunch_index == BUNCH_SIZE) 682 { 683 new = (struct msym_bunch *) xmalloc (sizeof (struct msym_bunch)); 684 msym_bunch_index = 0; 685 new->next = msym_bunch; 686 msym_bunch = new; 687 } 688 msymbol = &msym_bunch->contents[msym_bunch_index]; 689 SYMBOL_INIT_LANGUAGE_SPECIFIC (msymbol, language_unknown); 690 SYMBOL_LANGUAGE (msymbol) = language_auto; 691 SYMBOL_SET_NAMES (msymbol, (char *)name, strlen (name), objfile); 692 693 SYMBOL_VALUE_ADDRESS (msymbol) = address; 694 SYMBOL_SECTION (msymbol) = section; 695 SYMBOL_BFD_SECTION (msymbol) = bfd_section; 696 697 MSYMBOL_TYPE (msymbol) = ms_type; 698 /* FIXME: This info, if it remains, needs its own field. */ 699 MSYMBOL_INFO (msymbol) = info; /* FIXME! */ 700 MSYMBOL_SIZE (msymbol) = 0; 701 702 /* The hash pointers must be cleared! If they're not, 703 add_minsym_to_hash_table will NOT add this msymbol to the hash table. */ 704 msymbol->hash_next = NULL; 705 msymbol->demangled_hash_next = NULL; 706 707 msym_bunch_index++; 708 msym_count++; 709 OBJSTAT (objfile, n_minsyms++); 710 return msymbol; 711} 712 713/* Compare two minimal symbols by address and return a signed result based 714 on unsigned comparisons, so that we sort into unsigned numeric order. 715 Within groups with the same address, sort by name. */ 716 717static int 718compare_minimal_symbols (const void *fn1p, const void *fn2p) 719{ 720 const struct minimal_symbol *fn1; 721 const struct minimal_symbol *fn2; 722 723 fn1 = (const struct minimal_symbol *) fn1p; 724 fn2 = (const struct minimal_symbol *) fn2p; 725 726 if (SYMBOL_VALUE_ADDRESS (fn1) < SYMBOL_VALUE_ADDRESS (fn2)) 727 { 728 return (-1); /* addr 1 is less than addr 2 */ 729 } 730 else if (SYMBOL_VALUE_ADDRESS (fn1) > SYMBOL_VALUE_ADDRESS (fn2)) 731 { 732 return (1); /* addr 1 is greater than addr 2 */ 733 } 734 else 735 /* addrs are equal: sort by name */ 736 { 737 char *name1 = SYMBOL_LINKAGE_NAME (fn1); 738 char *name2 = SYMBOL_LINKAGE_NAME (fn2); 739 740 if (name1 && name2) /* both have names */ 741 return strcmp (name1, name2); 742 else if (name2) 743 return 1; /* fn1 has no name, so it is "less" */ 744 else if (name1) /* fn2 has no name, so it is "less" */ 745 return -1; 746 else 747 return (0); /* neither has a name, so they're equal. */ 748 } 749} 750 751/* Discard the currently collected minimal symbols, if any. If we wish 752 to save them for later use, we must have already copied them somewhere 753 else before calling this function. 754 755 FIXME: We could allocate the minimal symbol bunches on their own 756 obstack and then simply blow the obstack away when we are done with 757 it. Is it worth the extra trouble though? */ 758 759static void 760do_discard_minimal_symbols_cleanup (void *arg) 761{ 762 struct msym_bunch *next; 763 764 while (msym_bunch != NULL) 765 { 766 next = msym_bunch->next; 767 xfree (msym_bunch); 768 msym_bunch = next; 769 } 770} 771 772struct cleanup * 773make_cleanup_discard_minimal_symbols (void) 774{ 775 return make_cleanup (do_discard_minimal_symbols_cleanup, 0); 776} 777 778 779 780/* Compact duplicate entries out of a minimal symbol table by walking 781 through the table and compacting out entries with duplicate addresses 782 and matching names. Return the number of entries remaining. 783 784 On entry, the table resides between msymbol[0] and msymbol[mcount]. 785 On exit, it resides between msymbol[0] and msymbol[result_count]. 786 787 When files contain multiple sources of symbol information, it is 788 possible for the minimal symbol table to contain many duplicate entries. 789 As an example, SVR4 systems use ELF formatted object files, which 790 usually contain at least two different types of symbol tables (a 791 standard ELF one and a smaller dynamic linking table), as well as 792 DWARF debugging information for files compiled with -g. 793 794 Without compacting, the minimal symbol table for gdb itself contains 795 over a 1000 duplicates, about a third of the total table size. Aside 796 from the potential trap of not noticing that two successive entries 797 identify the same location, this duplication impacts the time required 798 to linearly scan the table, which is done in a number of places. So we 799 just do one linear scan here and toss out the duplicates. 800 801 Note that we are not concerned here about recovering the space that 802 is potentially freed up, because the strings themselves are allocated 803 on the objfile_obstack, and will get automatically freed when the symbol 804 table is freed. The caller can free up the unused minimal symbols at 805 the end of the compacted region if their allocation strategy allows it. 806 807 Also note we only go up to the next to last entry within the loop 808 and then copy the last entry explicitly after the loop terminates. 809 810 Since the different sources of information for each symbol may 811 have different levels of "completeness", we may have duplicates 812 that have one entry with type "mst_unknown" and the other with a 813 known type. So if the one we are leaving alone has type mst_unknown, 814 overwrite its type with the type from the one we are compacting out. */ 815 816static int 817compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount, 818 struct objfile *objfile) 819{ 820 struct minimal_symbol *copyfrom; 821 struct minimal_symbol *copyto; 822 823 if (mcount > 0) 824 { 825 copyfrom = copyto = msymbol; 826 while (copyfrom < msymbol + mcount - 1) 827 { 828 if (SYMBOL_VALUE_ADDRESS (copyfrom) 829 == SYMBOL_VALUE_ADDRESS ((copyfrom + 1)) 830 && strcmp (SYMBOL_LINKAGE_NAME (copyfrom), 831 SYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0) 832 { 833 if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown) 834 { 835 MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom); 836 } 837 copyfrom++; 838 } 839 else 840 *copyto++ = *copyfrom++; 841 } 842 *copyto++ = *copyfrom++; 843 mcount = copyto - msymbol; 844 } 845 return (mcount); 846} 847 848/* Build (or rebuild) the minimal symbol hash tables. This is necessary 849 after compacting or sorting the table since the entries move around 850 thus causing the internal minimal_symbol pointers to become jumbled. */ 851 852static void 853build_minimal_symbol_hash_tables (struct objfile *objfile) 854{ 855 int i; 856 struct minimal_symbol *msym; 857 858 /* Clear the hash tables. */ 859 for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++) 860 { 861 objfile->msymbol_hash[i] = 0; 862 objfile->msymbol_demangled_hash[i] = 0; 863 } 864 865 /* Now, (re)insert the actual entries. */ 866 for (i = objfile->minimal_symbol_count, msym = objfile->msymbols; 867 i > 0; 868 i--, msym++) 869 { 870 msym->hash_next = 0; 871 add_minsym_to_hash_table (msym, objfile->msymbol_hash); 872 873 msym->demangled_hash_next = 0; 874 if (SYMBOL_SEARCH_NAME (msym) != SYMBOL_LINKAGE_NAME (msym)) 875 add_minsym_to_demangled_hash_table (msym, 876 objfile->msymbol_demangled_hash); 877 } 878} 879 880/* Add the minimal symbols in the existing bunches to the objfile's official 881 minimal symbol table. In most cases there is no minimal symbol table yet 882 for this objfile, and the existing bunches are used to create one. Once 883 in a while (for shared libraries for example), we add symbols (e.g. common 884 symbols) to an existing objfile. 885 886 Because of the way minimal symbols are collected, we generally have no way 887 of knowing what source language applies to any particular minimal symbol. 888 Specifically, we have no way of knowing if the minimal symbol comes from a 889 C++ compilation unit or not. So for the sake of supporting cached 890 demangled C++ names, we have no choice but to try and demangle each new one 891 that comes in. If the demangling succeeds, then we assume it is a C++ 892 symbol and set the symbol's language and demangled name fields 893 appropriately. Note that in order to avoid unnecessary demanglings, and 894 allocating obstack space that subsequently can't be freed for the demangled 895 names, we mark all newly added symbols with language_auto. After 896 compaction of the minimal symbols, we go back and scan the entire minimal 897 symbol table looking for these new symbols. For each new symbol we attempt 898 to demangle it, and if successful, record it as a language_cplus symbol 899 and cache the demangled form on the symbol obstack. Symbols which don't 900 demangle are marked as language_unknown symbols, which inhibits future 901 attempts to demangle them if we later add more minimal symbols. */ 902 903void 904install_minimal_symbols (struct objfile *objfile) 905{ 906 int bindex; 907 int mcount; 908 struct msym_bunch *bunch; 909 struct minimal_symbol *msymbols; 910 int alloc_count; 911 912 if (msym_count > 0) 913 { 914 /* Allocate enough space in the obstack, into which we will gather the 915 bunches of new and existing minimal symbols, sort them, and then 916 compact out the duplicate entries. Once we have a final table, 917 we will give back the excess space. */ 918 919 alloc_count = msym_count + objfile->minimal_symbol_count + 1; 920 obstack_blank (&objfile->objfile_obstack, 921 alloc_count * sizeof (struct minimal_symbol)); 922 msymbols = (struct minimal_symbol *) 923 obstack_base (&objfile->objfile_obstack); 924 925 /* Copy in the existing minimal symbols, if there are any. */ 926 927 if (objfile->minimal_symbol_count) 928 memcpy ((char *) msymbols, (char *) objfile->msymbols, 929 objfile->minimal_symbol_count * sizeof (struct minimal_symbol)); 930 931 /* Walk through the list of minimal symbol bunches, adding each symbol 932 to the new contiguous array of symbols. Note that we start with the 933 current, possibly partially filled bunch (thus we use the current 934 msym_bunch_index for the first bunch we copy over), and thereafter 935 each bunch is full. */ 936 937 mcount = objfile->minimal_symbol_count; 938 939 for (bunch = msym_bunch; bunch != NULL; bunch = bunch->next) 940 { 941 for (bindex = 0; bindex < msym_bunch_index; bindex++, mcount++) 942 msymbols[mcount] = bunch->contents[bindex]; 943 msym_bunch_index = BUNCH_SIZE; 944 } 945 946 /* Sort the minimal symbols by address. */ 947 948 qsort (msymbols, mcount, sizeof (struct minimal_symbol), 949 compare_minimal_symbols); 950 951 /* Compact out any duplicates, and free up whatever space we are 952 no longer using. */ 953 954 mcount = compact_minimal_symbols (msymbols, mcount, objfile); 955 956 obstack_blank (&objfile->objfile_obstack, 957 (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol)); 958 msymbols = (struct minimal_symbol *) 959 obstack_finish (&objfile->objfile_obstack); 960 961 /* We also terminate the minimal symbol table with a "null symbol", 962 which is *not* included in the size of the table. This makes it 963 easier to find the end of the table when we are handed a pointer 964 to some symbol in the middle of it. Zero out the fields in the 965 "null symbol" allocated at the end of the array. Note that the 966 symbol count does *not* include this null symbol, which is why it 967 is indexed by mcount and not mcount-1. */ 968 969 SYMBOL_LINKAGE_NAME (&msymbols[mcount]) = NULL; 970 SYMBOL_VALUE_ADDRESS (&msymbols[mcount]) = 0; 971 MSYMBOL_INFO (&msymbols[mcount]) = NULL; 972 MSYMBOL_SIZE (&msymbols[mcount]) = 0; 973 MSYMBOL_TYPE (&msymbols[mcount]) = mst_unknown; 974 SYMBOL_INIT_LANGUAGE_SPECIFIC (&msymbols[mcount], language_unknown); 975 976 /* Attach the minimal symbol table to the specified objfile. 977 The strings themselves are also located in the objfile_obstack 978 of this objfile. */ 979 980 objfile->minimal_symbol_count = mcount; 981 objfile->msymbols = msymbols; 982 983 /* Try to guess the appropriate C++ ABI by looking at the names 984 of the minimal symbols in the table. */ 985 { 986 int i; 987 988 for (i = 0; i < mcount; i++) 989 { 990 /* If a symbol's name starts with _Z and was successfully 991 demangled, then we can assume we've found a GNU v3 symbol. 992 For now we set the C++ ABI globally; if the user is 993 mixing ABIs then the user will need to "set cp-abi" 994 manually. */ 995 const char *name = SYMBOL_LINKAGE_NAME (&objfile->msymbols[i]); 996 if (name[0] == '_' && name[1] == 'Z' 997 && SYMBOL_DEMANGLED_NAME (&objfile->msymbols[i]) != NULL) 998 { 999 set_cp_abi_as_auto_default ("gnu-v3"); 1000 break; 1001 } 1002 } 1003 } 1004 1005 /* Now build the hash tables; we can't do this incrementally 1006 at an earlier point since we weren't finished with the obstack 1007 yet. (And if the msymbol obstack gets moved, all the internal 1008 pointers to other msymbols need to be adjusted.) */ 1009 build_minimal_symbol_hash_tables (objfile); 1010 } 1011} 1012 1013/* Sort all the minimal symbols in OBJFILE. */ 1014 1015void 1016msymbols_sort (struct objfile *objfile) 1017{ 1018 qsort (objfile->msymbols, objfile->minimal_symbol_count, 1019 sizeof (struct minimal_symbol), compare_minimal_symbols); 1020 build_minimal_symbol_hash_tables (objfile); 1021} 1022 1023/* Check if PC is in a shared library trampoline code stub. 1024 Return minimal symbol for the trampoline entry or NULL if PC is not 1025 in a trampoline code stub. */ 1026 1027struct minimal_symbol * 1028lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc) 1029{ 1030 struct minimal_symbol *msymbol = lookup_minimal_symbol_by_pc (pc); 1031 1032 if (msymbol != NULL && MSYMBOL_TYPE (msymbol) == mst_solib_trampoline) 1033 return msymbol; 1034 return NULL; 1035} 1036 1037/* If PC is in a shared library trampoline code stub, return the 1038 address of the `real' function belonging to the stub. 1039 Return 0 if PC is not in a trampoline code stub or if the real 1040 function is not found in the minimal symbol table. 1041 1042 We may fail to find the right function if a function with the 1043 same name is defined in more than one shared library, but this 1044 is considered bad programming style. We could return 0 if we find 1045 a duplicate function in case this matters someday. */ 1046 1047CORE_ADDR 1048find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc) 1049{ 1050 struct objfile *objfile; 1051 struct minimal_symbol *msymbol; 1052 struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc); 1053 1054 if (tsymbol != NULL) 1055 { 1056 ALL_MSYMBOLS (objfile, msymbol) 1057 { 1058 if (MSYMBOL_TYPE (msymbol) == mst_text 1059 && strcmp (SYMBOL_LINKAGE_NAME (msymbol), 1060 SYMBOL_LINKAGE_NAME (tsymbol)) == 0) 1061 return SYMBOL_VALUE_ADDRESS (msymbol); 1062 } 1063 } 1064 return 0; 1065} 1066