| 1 | /* GDB routines for manipulating the minimal symbol tables. |
| 2 | Copyright (C) 1992-2020 Free Software Foundation, Inc. |
| 3 | Contributed by Cygnus Support, using pieces from other GDB modules. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 3 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | |
| 21 | /* This file contains support routines for creating, manipulating, and |
| 22 | destroying minimal symbol tables. |
| 23 | |
| 24 | Minimal symbol tables are used to hold some very basic information about |
| 25 | all defined global symbols (text, data, bss, abs, etc). The only two |
| 26 | required pieces of information are the symbol's name and the address |
| 27 | associated with that symbol. |
| 28 | |
| 29 | In many cases, even if a file was compiled with no special options for |
| 30 | debugging at all, as long as was not stripped it will contain sufficient |
| 31 | information to build useful minimal symbol tables using this structure. |
| 32 | |
| 33 | Even when a file contains enough debugging information to build a full |
| 34 | symbol table, these minimal symbols are still useful for quickly mapping |
| 35 | between names and addresses, and vice versa. They are also sometimes used |
| 36 | to figure out what full symbol table entries need to be read in. */ |
| 37 | |
| 38 | |
| 39 | #include "defs.h" |
| 40 | #include <ctype.h> |
| 41 | #include "symtab.h" |
| 42 | #include "bfd.h" |
| 43 | #include "filenames.h" |
| 44 | #include "symfile.h" |
| 45 | #include "objfiles.h" |
| 46 | #include "demangle.h" |
| 47 | #include "value.h" |
| 48 | #include "cp-abi.h" |
| 49 | #include "target.h" |
| 50 | #include "cp-support.h" |
| 51 | #include "language.h" |
| 52 | #include "cli/cli-utils.h" |
| 53 | #include "gdbsupport/symbol.h" |
| 54 | #include <algorithm> |
| 55 | #include "safe-ctype.h" |
| 56 | #include "gdbsupport/parallel-for.h" |
| 57 | |
| 58 | #if CXX_STD_THREAD |
| 59 | #include <mutex> |
| 60 | #endif |
| 61 | |
| 62 | /* See minsyms.h. */ |
| 63 | |
| 64 | bool |
| 65 | msymbol_is_function (struct objfile *objfile, minimal_symbol *minsym, |
| 66 | CORE_ADDR *func_address_p) |
| 67 | { |
| 68 | CORE_ADDR msym_addr = MSYMBOL_VALUE_ADDRESS (objfile, minsym); |
| 69 | |
| 70 | switch (minsym->type) |
| 71 | { |
| 72 | case mst_slot_got_plt: |
| 73 | case mst_data: |
| 74 | case mst_bss: |
| 75 | case mst_abs: |
| 76 | case mst_file_data: |
| 77 | case mst_file_bss: |
| 78 | case mst_data_gnu_ifunc: |
| 79 | { |
| 80 | struct gdbarch *gdbarch = get_objfile_arch (objfile); |
| 81 | CORE_ADDR pc |
| 82 | = gdbarch_convert_from_func_ptr_addr (gdbarch, msym_addr, |
| 83 | current_top_target ()); |
| 84 | if (pc != msym_addr) |
| 85 | { |
| 86 | if (func_address_p != NULL) |
| 87 | *func_address_p = pc; |
| 88 | return true; |
| 89 | } |
| 90 | return false; |
| 91 | } |
| 92 | default: |
| 93 | if (func_address_p != NULL) |
| 94 | *func_address_p = msym_addr; |
| 95 | return true; |
| 96 | } |
| 97 | } |
| 98 | |
| 99 | /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE. |
| 100 | At the end, copy them all into one newly allocated array. */ |
| 101 | |
| 102 | #define BUNCH_SIZE 127 |
| 103 | |
| 104 | struct msym_bunch |
| 105 | { |
| 106 | struct msym_bunch *next; |
| 107 | struct minimal_symbol contents[BUNCH_SIZE]; |
| 108 | }; |
| 109 | |
| 110 | /* See minsyms.h. */ |
| 111 | |
| 112 | unsigned int |
| 113 | msymbol_hash_iw (const char *string) |
| 114 | { |
| 115 | unsigned int hash = 0; |
| 116 | |
| 117 | while (*string && *string != '(') |
| 118 | { |
| 119 | string = skip_spaces (string); |
| 120 | if (*string && *string != '(') |
| 121 | { |
| 122 | hash = SYMBOL_HASH_NEXT (hash, *string); |
| 123 | ++string; |
| 124 | } |
| 125 | } |
| 126 | return hash; |
| 127 | } |
| 128 | |
| 129 | /* See minsyms.h. */ |
| 130 | |
| 131 | unsigned int |
| 132 | msymbol_hash (const char *string) |
| 133 | { |
| 134 | unsigned int hash = 0; |
| 135 | |
| 136 | for (; *string; ++string) |
| 137 | hash = SYMBOL_HASH_NEXT (hash, *string); |
| 138 | return hash; |
| 139 | } |
| 140 | |
| 141 | /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */ |
| 142 | static void |
| 143 | add_minsym_to_hash_table (struct minimal_symbol *sym, |
| 144 | struct minimal_symbol **table, |
| 145 | unsigned int hash_value) |
| 146 | { |
| 147 | if (sym->hash_next == NULL) |
| 148 | { |
| 149 | unsigned int hash = hash_value % MINIMAL_SYMBOL_HASH_SIZE; |
| 150 | |
| 151 | sym->hash_next = table[hash]; |
| 152 | table[hash] = sym; |
| 153 | } |
| 154 | } |
| 155 | |
| 156 | /* Add the minimal symbol SYM to an objfile's minsym demangled hash table, |
| 157 | TABLE. */ |
| 158 | static void |
| 159 | add_minsym_to_demangled_hash_table (struct minimal_symbol *sym, |
| 160 | struct objfile *objfile, |
| 161 | unsigned int hash_value) |
| 162 | { |
| 163 | if (sym->demangled_hash_next == NULL) |
| 164 | { |
| 165 | objfile->per_bfd->demangled_hash_languages.set (sym->language ()); |
| 166 | |
| 167 | struct minimal_symbol **table |
| 168 | = objfile->per_bfd->msymbol_demangled_hash; |
| 169 | unsigned int hash_index = hash_value % MINIMAL_SYMBOL_HASH_SIZE; |
| 170 | sym->demangled_hash_next = table[hash_index]; |
| 171 | table[hash_index] = sym; |
| 172 | } |
| 173 | } |
| 174 | |
| 175 | /* Worker object for lookup_minimal_symbol. Stores temporary results |
| 176 | while walking the symbol tables. */ |
| 177 | |
| 178 | struct found_minimal_symbols |
| 179 | { |
| 180 | /* External symbols are best. */ |
| 181 | bound_minimal_symbol external_symbol {}; |
| 182 | |
| 183 | /* File-local symbols are next best. */ |
| 184 | bound_minimal_symbol file_symbol {}; |
| 185 | |
| 186 | /* Symbols for shared library trampolines are next best. */ |
| 187 | bound_minimal_symbol trampoline_symbol {}; |
| 188 | |
| 189 | /* Called when a symbol name matches. Check if the minsym is a |
| 190 | better type than what we had already found, and record it in one |
| 191 | of the members fields if so. Returns true if we collected the |
| 192 | real symbol, in which case we can stop searching. */ |
| 193 | bool maybe_collect (const char *sfile, objfile *objf, |
| 194 | minimal_symbol *msymbol); |
| 195 | }; |
| 196 | |
| 197 | /* See declaration above. */ |
| 198 | |
| 199 | bool |
| 200 | found_minimal_symbols::maybe_collect (const char *sfile, |
| 201 | struct objfile *objfile, |
| 202 | minimal_symbol *msymbol) |
| 203 | { |
| 204 | switch (MSYMBOL_TYPE (msymbol)) |
| 205 | { |
| 206 | case mst_file_text: |
| 207 | case mst_file_data: |
| 208 | case mst_file_bss: |
| 209 | if (sfile == NULL |
| 210 | || filename_cmp (msymbol->filename, sfile) == 0) |
| 211 | { |
| 212 | file_symbol.minsym = msymbol; |
| 213 | file_symbol.objfile = objfile; |
| 214 | } |
| 215 | break; |
| 216 | |
| 217 | case mst_solib_trampoline: |
| 218 | |
| 219 | /* If a trampoline symbol is found, we prefer to keep |
| 220 | looking for the *real* symbol. If the actual symbol |
| 221 | is not found, then we'll use the trampoline |
| 222 | entry. */ |
| 223 | if (trampoline_symbol.minsym == NULL) |
| 224 | { |
| 225 | trampoline_symbol.minsym = msymbol; |
| 226 | trampoline_symbol.objfile = objfile; |
| 227 | } |
| 228 | break; |
| 229 | |
| 230 | case mst_unknown: |
| 231 | default: |
| 232 | external_symbol.minsym = msymbol; |
| 233 | external_symbol.objfile = objfile; |
| 234 | /* We have the real symbol. No use looking further. */ |
| 235 | return true; |
| 236 | } |
| 237 | |
| 238 | /* Keep looking. */ |
| 239 | return false; |
| 240 | } |
| 241 | |
| 242 | /* Walk the mangled name hash table, and pass each symbol whose name |
| 243 | matches LOOKUP_NAME according to NAMECMP to FOUND. */ |
| 244 | |
| 245 | static void |
| 246 | lookup_minimal_symbol_mangled (const char *lookup_name, |
| 247 | const char *sfile, |
| 248 | struct objfile *objfile, |
| 249 | struct minimal_symbol **table, |
| 250 | unsigned int hash, |
| 251 | int (*namecmp) (const char *, const char *), |
| 252 | found_minimal_symbols &found) |
| 253 | { |
| 254 | for (minimal_symbol *msymbol = table[hash]; |
| 255 | msymbol != NULL; |
| 256 | msymbol = msymbol->hash_next) |
| 257 | { |
| 258 | const char *symbol_name = msymbol->linkage_name (); |
| 259 | |
| 260 | if (namecmp (symbol_name, lookup_name) == 0 |
| 261 | && found.maybe_collect (sfile, objfile, msymbol)) |
| 262 | return; |
| 263 | } |
| 264 | } |
| 265 | |
| 266 | /* Walk the demangled name hash table, and pass each symbol whose name |
| 267 | matches LOOKUP_NAME according to MATCHER to FOUND. */ |
| 268 | |
| 269 | static void |
| 270 | lookup_minimal_symbol_demangled (const lookup_name_info &lookup_name, |
| 271 | const char *sfile, |
| 272 | struct objfile *objfile, |
| 273 | struct minimal_symbol **table, |
| 274 | unsigned int hash, |
| 275 | symbol_name_matcher_ftype *matcher, |
| 276 | found_minimal_symbols &found) |
| 277 | { |
| 278 | for (minimal_symbol *msymbol = table[hash]; |
| 279 | msymbol != NULL; |
| 280 | msymbol = msymbol->demangled_hash_next) |
| 281 | { |
| 282 | const char *symbol_name = msymbol->search_name (); |
| 283 | |
| 284 | if (matcher (symbol_name, lookup_name, NULL) |
| 285 | && found.maybe_collect (sfile, objfile, msymbol)) |
| 286 | return; |
| 287 | } |
| 288 | } |
| 289 | |
| 290 | /* Look through all the current minimal symbol tables and find the |
| 291 | first minimal symbol that matches NAME. If OBJF is non-NULL, limit |
| 292 | the search to that objfile. If SFILE is non-NULL, the only file-scope |
| 293 | symbols considered will be from that source file (global symbols are |
| 294 | still preferred). Returns a pointer to the minimal symbol that |
| 295 | matches, or NULL if no match is found. |
| 296 | |
| 297 | Note: One instance where there may be duplicate minimal symbols with |
| 298 | the same name is when the symbol tables for a shared library and the |
| 299 | symbol tables for an executable contain global symbols with the same |
| 300 | names (the dynamic linker deals with the duplication). |
| 301 | |
| 302 | It's also possible to have minimal symbols with different mangled |
| 303 | names, but identical demangled names. For example, the GNU C++ v3 |
| 304 | ABI requires the generation of two (or perhaps three) copies of |
| 305 | constructor functions --- "in-charge", "not-in-charge", and |
| 306 | "allocate" copies; destructors may be duplicated as well. |
| 307 | Obviously, there must be distinct mangled names for each of these, |
| 308 | but the demangled names are all the same: S::S or S::~S. */ |
| 309 | |
| 310 | struct bound_minimal_symbol |
| 311 | lookup_minimal_symbol (const char *name, const char *sfile, |
| 312 | struct objfile *objf) |
| 313 | { |
| 314 | found_minimal_symbols found; |
| 315 | |
| 316 | unsigned int mangled_hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE; |
| 317 | |
| 318 | auto *mangled_cmp |
| 319 | = (case_sensitivity == case_sensitive_on |
| 320 | ? strcmp |
| 321 | : strcasecmp); |
| 322 | |
| 323 | if (sfile != NULL) |
| 324 | sfile = lbasename (sfile); |
| 325 | |
| 326 | lookup_name_info lookup_name (name, symbol_name_match_type::FULL); |
| 327 | |
| 328 | for (objfile *objfile : current_program_space->objfiles ()) |
| 329 | { |
| 330 | if (found.external_symbol.minsym != NULL) |
| 331 | break; |
| 332 | |
| 333 | if (objf == NULL || objf == objfile |
| 334 | || objf == objfile->separate_debug_objfile_backlink) |
| 335 | { |
| 336 | if (symbol_lookup_debug) |
| 337 | { |
| 338 | fprintf_unfiltered (gdb_stdlog, |
| 339 | "lookup_minimal_symbol (%s, %s, %s)\n", |
| 340 | name, sfile != NULL ? sfile : "NULL", |
| 341 | objfile_debug_name (objfile)); |
| 342 | } |
| 343 | |
| 344 | /* Do two passes: the first over the ordinary hash table, |
| 345 | and the second over the demangled hash table. */ |
| 346 | lookup_minimal_symbol_mangled (name, sfile, objfile, |
| 347 | objfile->per_bfd->msymbol_hash, |
| 348 | mangled_hash, mangled_cmp, found); |
| 349 | |
| 350 | /* If not found, try the demangled hash table. */ |
| 351 | if (found.external_symbol.minsym == NULL) |
| 352 | { |
| 353 | /* Once for each language in the demangled hash names |
| 354 | table (usually just zero or one languages). */ |
| 355 | for (unsigned iter = 0; iter < nr_languages; ++iter) |
| 356 | { |
| 357 | if (!objfile->per_bfd->demangled_hash_languages.test (iter)) |
| 358 | continue; |
| 359 | enum language lang = (enum language) iter; |
| 360 | |
| 361 | unsigned int hash |
| 362 | = (lookup_name.search_name_hash (lang) |
| 363 | % MINIMAL_SYMBOL_HASH_SIZE); |
| 364 | |
| 365 | symbol_name_matcher_ftype *match |
| 366 | = get_symbol_name_matcher (language_def (lang), |
| 367 | lookup_name); |
| 368 | struct minimal_symbol **msymbol_demangled_hash |
| 369 | = objfile->per_bfd->msymbol_demangled_hash; |
| 370 | |
| 371 | lookup_minimal_symbol_demangled (lookup_name, sfile, objfile, |
| 372 | msymbol_demangled_hash, |
| 373 | hash, match, found); |
| 374 | |
| 375 | if (found.external_symbol.minsym != NULL) |
| 376 | break; |
| 377 | } |
| 378 | } |
| 379 | } |
| 380 | } |
| 381 | |
| 382 | /* External symbols are best. */ |
| 383 | if (found.external_symbol.minsym != NULL) |
| 384 | { |
| 385 | if (symbol_lookup_debug) |
| 386 | { |
| 387 | minimal_symbol *minsym = found.external_symbol.minsym; |
| 388 | |
| 389 | fprintf_unfiltered (gdb_stdlog, |
| 390 | "lookup_minimal_symbol (...) = %s (external)\n", |
| 391 | host_address_to_string (minsym)); |
| 392 | } |
| 393 | return found.external_symbol; |
| 394 | } |
| 395 | |
| 396 | /* File-local symbols are next best. */ |
| 397 | if (found.file_symbol.minsym != NULL) |
| 398 | { |
| 399 | if (symbol_lookup_debug) |
| 400 | { |
| 401 | minimal_symbol *minsym = found.file_symbol.minsym; |
| 402 | |
| 403 | fprintf_unfiltered (gdb_stdlog, |
| 404 | "lookup_minimal_symbol (...) = %s (file-local)\n", |
| 405 | host_address_to_string (minsym)); |
| 406 | } |
| 407 | return found.file_symbol; |
| 408 | } |
| 409 | |
| 410 | /* Symbols for shared library trampolines are next best. */ |
| 411 | if (found.trampoline_symbol.minsym != NULL) |
| 412 | { |
| 413 | if (symbol_lookup_debug) |
| 414 | { |
| 415 | minimal_symbol *minsym = found.trampoline_symbol.minsym; |
| 416 | |
| 417 | fprintf_unfiltered (gdb_stdlog, |
| 418 | "lookup_minimal_symbol (...) = %s (trampoline)\n", |
| 419 | host_address_to_string (minsym)); |
| 420 | } |
| 421 | |
| 422 | return found.trampoline_symbol; |
| 423 | } |
| 424 | |
| 425 | /* Not found. */ |
| 426 | if (symbol_lookup_debug) |
| 427 | fprintf_unfiltered (gdb_stdlog, "lookup_minimal_symbol (...) = NULL\n"); |
| 428 | return {}; |
| 429 | } |
| 430 | |
| 431 | /* See minsyms.h. */ |
| 432 | |
| 433 | struct bound_minimal_symbol |
| 434 | lookup_bound_minimal_symbol (const char *name) |
| 435 | { |
| 436 | return lookup_minimal_symbol (name, NULL, NULL); |
| 437 | } |
| 438 | |
| 439 | /* See gdbsupport/symbol.h. */ |
| 440 | |
| 441 | int |
| 442 | find_minimal_symbol_address (const char *name, CORE_ADDR *addr, |
| 443 | struct objfile *objfile) |
| 444 | { |
| 445 | struct bound_minimal_symbol sym |
| 446 | = lookup_minimal_symbol (name, NULL, objfile); |
| 447 | |
| 448 | if (sym.minsym != NULL) |
| 449 | *addr = BMSYMBOL_VALUE_ADDRESS (sym); |
| 450 | |
| 451 | return sym.minsym == NULL; |
| 452 | } |
| 453 | |
| 454 | /* Get the lookup name form best suitable for linkage name |
| 455 | matching. */ |
| 456 | |
| 457 | static const char * |
| 458 | linkage_name_str (const lookup_name_info &lookup_name) |
| 459 | { |
| 460 | /* Unlike most languages (including C++), Ada uses the |
| 461 | encoded/linkage name as the search name recorded in symbols. So |
| 462 | if debugging in Ada mode, prefer the Ada-encoded name. This also |
| 463 | makes Ada's verbatim match syntax ("<...>") work, because |
| 464 | "lookup_name.name()" includes the "<>"s, while |
| 465 | "lookup_name.ada().lookup_name()" is the encoded name with "<>"s |
| 466 | stripped. */ |
| 467 | if (current_language->la_language == language_ada) |
| 468 | return lookup_name.ada ().lookup_name ().c_str (); |
| 469 | |
| 470 | return lookup_name.name ().c_str (); |
| 471 | } |
| 472 | |
| 473 | /* See minsyms.h. */ |
| 474 | |
| 475 | void |
| 476 | iterate_over_minimal_symbols |
| 477 | (struct objfile *objf, const lookup_name_info &lookup_name, |
| 478 | gdb::function_view<bool (struct minimal_symbol *)> callback) |
| 479 | { |
| 480 | /* The first pass is over the ordinary hash table. */ |
| 481 | { |
| 482 | const char *name = linkage_name_str (lookup_name); |
| 483 | unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE; |
| 484 | auto *mangled_cmp |
| 485 | = (case_sensitivity == case_sensitive_on |
| 486 | ? strcmp |
| 487 | : strcasecmp); |
| 488 | |
| 489 | for (minimal_symbol *iter = objf->per_bfd->msymbol_hash[hash]; |
| 490 | iter != NULL; |
| 491 | iter = iter->hash_next) |
| 492 | { |
| 493 | if (mangled_cmp (iter->linkage_name (), name) == 0) |
| 494 | if (callback (iter)) |
| 495 | return; |
| 496 | } |
| 497 | } |
| 498 | |
| 499 | /* The second pass is over the demangled table. Once for each |
| 500 | language in the demangled hash names table (usually just zero or |
| 501 | one). */ |
| 502 | for (unsigned liter = 0; liter < nr_languages; ++liter) |
| 503 | { |
| 504 | if (!objf->per_bfd->demangled_hash_languages.test (liter)) |
| 505 | continue; |
| 506 | |
| 507 | enum language lang = (enum language) liter; |
| 508 | const language_defn *lang_def = language_def (lang); |
| 509 | symbol_name_matcher_ftype *name_match |
| 510 | = get_symbol_name_matcher (lang_def, lookup_name); |
| 511 | |
| 512 | unsigned int hash |
| 513 | = lookup_name.search_name_hash (lang) % MINIMAL_SYMBOL_HASH_SIZE; |
| 514 | for (minimal_symbol *iter = objf->per_bfd->msymbol_demangled_hash[hash]; |
| 515 | iter != NULL; |
| 516 | iter = iter->demangled_hash_next) |
| 517 | if (name_match (iter->search_name (), lookup_name, NULL)) |
| 518 | if (callback (iter)) |
| 519 | return; |
| 520 | } |
| 521 | } |
| 522 | |
| 523 | /* See minsyms.h. */ |
| 524 | |
| 525 | bound_minimal_symbol |
| 526 | lookup_minimal_symbol_linkage (const char *name, struct objfile *objf) |
| 527 | { |
| 528 | unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE; |
| 529 | |
| 530 | for (objfile *objfile : objf->separate_debug_objfiles ()) |
| 531 | { |
| 532 | for (minimal_symbol *msymbol = objfile->per_bfd->msymbol_hash[hash]; |
| 533 | msymbol != NULL; |
| 534 | msymbol = msymbol->hash_next) |
| 535 | { |
| 536 | if (strcmp (msymbol->linkage_name (), name) == 0 |
| 537 | && (MSYMBOL_TYPE (msymbol) == mst_data |
| 538 | || MSYMBOL_TYPE (msymbol) == mst_bss)) |
| 539 | return {msymbol, objfile}; |
| 540 | } |
| 541 | } |
| 542 | |
| 543 | return {}; |
| 544 | } |
| 545 | |
| 546 | /* See minsyms.h. */ |
| 547 | |
| 548 | struct bound_minimal_symbol |
| 549 | lookup_minimal_symbol_text (const char *name, struct objfile *objf) |
| 550 | { |
| 551 | struct minimal_symbol *msymbol; |
| 552 | struct bound_minimal_symbol found_symbol = { NULL, NULL }; |
| 553 | struct bound_minimal_symbol found_file_symbol = { NULL, NULL }; |
| 554 | |
| 555 | unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE; |
| 556 | |
| 557 | for (objfile *objfile : current_program_space->objfiles ()) |
| 558 | { |
| 559 | if (found_symbol.minsym != NULL) |
| 560 | break; |
| 561 | |
| 562 | if (objf == NULL || objf == objfile |
| 563 | || objf == objfile->separate_debug_objfile_backlink) |
| 564 | { |
| 565 | for (msymbol = objfile->per_bfd->msymbol_hash[hash]; |
| 566 | msymbol != NULL && found_symbol.minsym == NULL; |
| 567 | msymbol = msymbol->hash_next) |
| 568 | { |
| 569 | if (strcmp (msymbol->linkage_name (), name) == 0 && |
| 570 | (MSYMBOL_TYPE (msymbol) == mst_text |
| 571 | || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc |
| 572 | || MSYMBOL_TYPE (msymbol) == mst_file_text)) |
| 573 | { |
| 574 | switch (MSYMBOL_TYPE (msymbol)) |
| 575 | { |
| 576 | case mst_file_text: |
| 577 | found_file_symbol.minsym = msymbol; |
| 578 | found_file_symbol.objfile = objfile; |
| 579 | break; |
| 580 | default: |
| 581 | found_symbol.minsym = msymbol; |
| 582 | found_symbol.objfile = objfile; |
| 583 | break; |
| 584 | } |
| 585 | } |
| 586 | } |
| 587 | } |
| 588 | } |
| 589 | /* External symbols are best. */ |
| 590 | if (found_symbol.minsym) |
| 591 | return found_symbol; |
| 592 | |
| 593 | /* File-local symbols are next best. */ |
| 594 | return found_file_symbol; |
| 595 | } |
| 596 | |
| 597 | /* See minsyms.h. */ |
| 598 | |
| 599 | struct minimal_symbol * |
| 600 | lookup_minimal_symbol_by_pc_name (CORE_ADDR pc, const char *name, |
| 601 | struct objfile *objf) |
| 602 | { |
| 603 | struct minimal_symbol *msymbol; |
| 604 | |
| 605 | unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE; |
| 606 | |
| 607 | for (objfile *objfile : current_program_space->objfiles ()) |
| 608 | { |
| 609 | if (objf == NULL || objf == objfile |
| 610 | || objf == objfile->separate_debug_objfile_backlink) |
| 611 | { |
| 612 | for (msymbol = objfile->per_bfd->msymbol_hash[hash]; |
| 613 | msymbol != NULL; |
| 614 | msymbol = msymbol->hash_next) |
| 615 | { |
| 616 | if (MSYMBOL_VALUE_ADDRESS (objfile, msymbol) == pc |
| 617 | && strcmp (msymbol->linkage_name (), name) == 0) |
| 618 | return msymbol; |
| 619 | } |
| 620 | } |
| 621 | } |
| 622 | |
| 623 | return NULL; |
| 624 | } |
| 625 | |
| 626 | /* A helper function that makes *PC section-relative. This searches |
| 627 | the sections of OBJFILE and if *PC is in a section, it subtracts |
| 628 | the section offset and returns true. Otherwise it returns |
| 629 | false. */ |
| 630 | |
| 631 | static int |
| 632 | frob_address (struct objfile *objfile, CORE_ADDR *pc) |
| 633 | { |
| 634 | struct obj_section *iter; |
| 635 | |
| 636 | ALL_OBJFILE_OSECTIONS (objfile, iter) |
| 637 | { |
| 638 | if (*pc >= obj_section_addr (iter) && *pc < obj_section_endaddr (iter)) |
| 639 | { |
| 640 | *pc -= obj_section_offset (iter); |
| 641 | return 1; |
| 642 | } |
| 643 | } |
| 644 | |
| 645 | return 0; |
| 646 | } |
| 647 | |
| 648 | /* Helper for lookup_minimal_symbol_by_pc_section. Convert a |
| 649 | lookup_msym_prefer to a minimal_symbol_type. */ |
| 650 | |
| 651 | static minimal_symbol_type |
| 652 | msym_prefer_to_msym_type (lookup_msym_prefer prefer) |
| 653 | { |
| 654 | switch (prefer) |
| 655 | { |
| 656 | case lookup_msym_prefer::TEXT: |
| 657 | return mst_text; |
| 658 | case lookup_msym_prefer::TRAMPOLINE: |
| 659 | return mst_solib_trampoline; |
| 660 | case lookup_msym_prefer::GNU_IFUNC: |
| 661 | return mst_text_gnu_ifunc; |
| 662 | } |
| 663 | |
| 664 | /* Assert here instead of in a default switch case above so that |
| 665 | -Wswitch warns if a new enumerator is added. */ |
| 666 | gdb_assert_not_reached ("unhandled lookup_msym_prefer"); |
| 667 | } |
| 668 | |
| 669 | /* Search through the minimal symbol table for each objfile and find |
| 670 | the symbol whose address is the largest address that is still less |
| 671 | than or equal to PC, and matches SECTION (which is not NULL). |
| 672 | Returns a pointer to the minimal symbol if such a symbol is found, |
| 673 | or NULL if PC is not in a suitable range. |
| 674 | Note that we need to look through ALL the minimal symbol tables |
| 675 | before deciding on the symbol that comes closest to the specified PC. |
| 676 | This is because objfiles can overlap, for example objfile A has .text |
| 677 | at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and |
| 678 | .data at 0x40048. |
| 679 | |
| 680 | If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when |
| 681 | there are text and trampoline symbols at the same address. |
| 682 | Otherwise prefer mst_text symbols. */ |
| 683 | |
| 684 | bound_minimal_symbol |
| 685 | lookup_minimal_symbol_by_pc_section (CORE_ADDR pc_in, struct obj_section *section, |
| 686 | lookup_msym_prefer prefer) |
| 687 | { |
| 688 | int lo; |
| 689 | int hi; |
| 690 | int newobj; |
| 691 | struct minimal_symbol *msymbol; |
| 692 | struct minimal_symbol *best_symbol = NULL; |
| 693 | struct objfile *best_objfile = NULL; |
| 694 | struct bound_minimal_symbol result; |
| 695 | |
| 696 | if (section == NULL) |
| 697 | { |
| 698 | section = find_pc_section (pc_in); |
| 699 | if (section == NULL) |
| 700 | return {}; |
| 701 | } |
| 702 | |
| 703 | minimal_symbol_type want_type = msym_prefer_to_msym_type (prefer); |
| 704 | |
| 705 | /* We can not require the symbol found to be in section, because |
| 706 | e.g. IRIX 6.5 mdebug relies on this code returning an absolute |
| 707 | symbol - but find_pc_section won't return an absolute section and |
| 708 | hence the code below would skip over absolute symbols. We can |
| 709 | still take advantage of the call to find_pc_section, though - the |
| 710 | object file still must match. In case we have separate debug |
| 711 | files, search both the file and its separate debug file. There's |
| 712 | no telling which one will have the minimal symbols. */ |
| 713 | |
| 714 | gdb_assert (section != NULL); |
| 715 | |
| 716 | for (objfile *objfile : section->objfile->separate_debug_objfiles ()) |
| 717 | { |
| 718 | CORE_ADDR pc = pc_in; |
| 719 | |
| 720 | /* If this objfile has a minimal symbol table, go search it |
| 721 | using a binary search. */ |
| 722 | |
| 723 | if (objfile->per_bfd->minimal_symbol_count > 0) |
| 724 | { |
| 725 | int best_zero_sized = -1; |
| 726 | |
| 727 | msymbol = objfile->per_bfd->msymbols.get (); |
| 728 | lo = 0; |
| 729 | hi = objfile->per_bfd->minimal_symbol_count - 1; |
| 730 | |
| 731 | /* This code assumes that the minimal symbols are sorted by |
| 732 | ascending address values. If the pc value is greater than or |
| 733 | equal to the first symbol's address, then some symbol in this |
| 734 | minimal symbol table is a suitable candidate for being the |
| 735 | "best" symbol. This includes the last real symbol, for cases |
| 736 | where the pc value is larger than any address in this vector. |
| 737 | |
| 738 | By iterating until the address associated with the current |
| 739 | hi index (the endpoint of the test interval) is less than |
| 740 | or equal to the desired pc value, we accomplish two things: |
| 741 | (1) the case where the pc value is larger than any minimal |
| 742 | symbol address is trivially solved, (2) the address associated |
| 743 | with the hi index is always the one we want when the iteration |
| 744 | terminates. In essence, we are iterating the test interval |
| 745 | down until the pc value is pushed out of it from the high end. |
| 746 | |
| 747 | Warning: this code is trickier than it would appear at first. */ |
| 748 | |
| 749 | if (frob_address (objfile, &pc) |
| 750 | && pc >= MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[lo])) |
| 751 | { |
| 752 | while (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) > pc) |
| 753 | { |
| 754 | /* pc is still strictly less than highest address. */ |
| 755 | /* Note "new" will always be >= lo. */ |
| 756 | newobj = (lo + hi) / 2; |
| 757 | if ((MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[newobj]) >= pc) |
| 758 | || (lo == newobj)) |
| 759 | { |
| 760 | hi = newobj; |
| 761 | } |
| 762 | else |
| 763 | { |
| 764 | lo = newobj; |
| 765 | } |
| 766 | } |
| 767 | |
| 768 | /* If we have multiple symbols at the same address, we want |
| 769 | hi to point to the last one. That way we can find the |
| 770 | right symbol if it has an index greater than hi. */ |
| 771 | while (hi < objfile->per_bfd->minimal_symbol_count - 1 |
| 772 | && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) |
| 773 | == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi + 1]))) |
| 774 | hi++; |
| 775 | |
| 776 | /* Skip various undesirable symbols. */ |
| 777 | while (hi >= 0) |
| 778 | { |
| 779 | /* Skip any absolute symbols. This is apparently |
| 780 | what adb and dbx do, and is needed for the CM-5. |
| 781 | There are two known possible problems: (1) on |
| 782 | ELF, apparently end, edata, etc. are absolute. |
| 783 | Not sure ignoring them here is a big deal, but if |
| 784 | we want to use them, the fix would go in |
| 785 | elfread.c. (2) I think shared library entry |
| 786 | points on the NeXT are absolute. If we want |
| 787 | special handling for this it probably should be |
| 788 | triggered by a special mst_abs_or_lib or some |
| 789 | such. */ |
| 790 | |
| 791 | if (MSYMBOL_TYPE (&msymbol[hi]) == mst_abs) |
| 792 | { |
| 793 | hi--; |
| 794 | continue; |
| 795 | } |
| 796 | |
| 797 | /* If SECTION was specified, skip any symbol from |
| 798 | wrong section. */ |
| 799 | if (section |
| 800 | /* Some types of debug info, such as COFF, |
| 801 | don't fill the bfd_section member, so don't |
| 802 | throw away symbols on those platforms. */ |
| 803 | && MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]) != NULL |
| 804 | && (!matching_obj_sections |
| 805 | (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]), |
| 806 | section))) |
| 807 | { |
| 808 | hi--; |
| 809 | continue; |
| 810 | } |
| 811 | |
| 812 | /* If we are looking for a trampoline and this is a |
| 813 | text symbol, or the other way around, check the |
| 814 | preceding symbol too. If they are otherwise |
| 815 | identical prefer that one. */ |
| 816 | if (hi > 0 |
| 817 | && MSYMBOL_TYPE (&msymbol[hi]) != want_type |
| 818 | && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type |
| 819 | && (MSYMBOL_SIZE (&msymbol[hi]) |
| 820 | == MSYMBOL_SIZE (&msymbol[hi - 1])) |
| 821 | && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) |
| 822 | == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1])) |
| 823 | && (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]) |
| 824 | == MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi - 1]))) |
| 825 | { |
| 826 | hi--; |
| 827 | continue; |
| 828 | } |
| 829 | |
| 830 | /* If the minimal symbol has a zero size, save it |
| 831 | but keep scanning backwards looking for one with |
| 832 | a non-zero size. A zero size may mean that the |
| 833 | symbol isn't an object or function (e.g. a |
| 834 | label), or it may just mean that the size was not |
| 835 | specified. */ |
| 836 | if (MSYMBOL_SIZE (&msymbol[hi]) == 0) |
| 837 | { |
| 838 | if (best_zero_sized == -1) |
| 839 | best_zero_sized = hi; |
| 840 | hi--; |
| 841 | continue; |
| 842 | } |
| 843 | |
| 844 | /* If we are past the end of the current symbol, try |
| 845 | the previous symbol if it has a larger overlapping |
| 846 | size. This happens on i686-pc-linux-gnu with glibc; |
| 847 | the nocancel variants of system calls are inside |
| 848 | the cancellable variants, but both have sizes. */ |
| 849 | if (hi > 0 |
| 850 | && MSYMBOL_SIZE (&msymbol[hi]) != 0 |
| 851 | && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) |
| 852 | + MSYMBOL_SIZE (&msymbol[hi])) |
| 853 | && pc < (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1]) |
| 854 | + MSYMBOL_SIZE (&msymbol[hi - 1]))) |
| 855 | { |
| 856 | hi--; |
| 857 | continue; |
| 858 | } |
| 859 | |
| 860 | /* Otherwise, this symbol must be as good as we're going |
| 861 | to get. */ |
| 862 | break; |
| 863 | } |
| 864 | |
| 865 | /* If HI has a zero size, and best_zero_sized is set, |
| 866 | then we had two or more zero-sized symbols; prefer |
| 867 | the first one we found (which may have a higher |
| 868 | address). Also, if we ran off the end, be sure |
| 869 | to back up. */ |
| 870 | if (best_zero_sized != -1 |
| 871 | && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0)) |
| 872 | hi = best_zero_sized; |
| 873 | |
| 874 | /* If the minimal symbol has a non-zero size, and this |
| 875 | PC appears to be outside the symbol's contents, then |
| 876 | refuse to use this symbol. If we found a zero-sized |
| 877 | symbol with an address greater than this symbol's, |
| 878 | use that instead. We assume that if symbols have |
| 879 | specified sizes, they do not overlap. */ |
| 880 | |
| 881 | if (hi >= 0 |
| 882 | && MSYMBOL_SIZE (&msymbol[hi]) != 0 |
| 883 | && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) |
| 884 | + MSYMBOL_SIZE (&msymbol[hi]))) |
| 885 | { |
| 886 | if (best_zero_sized != -1) |
| 887 | hi = best_zero_sized; |
| 888 | else |
| 889 | /* Go on to the next object file. */ |
| 890 | continue; |
| 891 | } |
| 892 | |
| 893 | /* The minimal symbol indexed by hi now is the best one in this |
| 894 | objfile's minimal symbol table. See if it is the best one |
| 895 | overall. */ |
| 896 | |
| 897 | if (hi >= 0 |
| 898 | && ((best_symbol == NULL) || |
| 899 | (MSYMBOL_VALUE_RAW_ADDRESS (best_symbol) < |
| 900 | MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])))) |
| 901 | { |
| 902 | best_symbol = &msymbol[hi]; |
| 903 | best_objfile = objfile; |
| 904 | } |
| 905 | } |
| 906 | } |
| 907 | } |
| 908 | |
| 909 | result.minsym = best_symbol; |
| 910 | result.objfile = best_objfile; |
| 911 | return result; |
| 912 | } |
| 913 | |
| 914 | /* See minsyms.h. */ |
| 915 | |
| 916 | struct bound_minimal_symbol |
| 917 | lookup_minimal_symbol_by_pc (CORE_ADDR pc) |
| 918 | { |
| 919 | return lookup_minimal_symbol_by_pc_section (pc, NULL); |
| 920 | } |
| 921 | |
| 922 | /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver. */ |
| 923 | |
| 924 | bool |
| 925 | in_gnu_ifunc_stub (CORE_ADDR pc) |
| 926 | { |
| 927 | bound_minimal_symbol msymbol |
| 928 | = lookup_minimal_symbol_by_pc_section (pc, NULL, |
| 929 | lookup_msym_prefer::GNU_IFUNC); |
| 930 | return msymbol.minsym && MSYMBOL_TYPE (msymbol.minsym) == mst_text_gnu_ifunc; |
| 931 | } |
| 932 | |
| 933 | /* See elf_gnu_ifunc_resolve_addr for its real implementation. */ |
| 934 | |
| 935 | static CORE_ADDR |
| 936 | stub_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc) |
| 937 | { |
| 938 | error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without " |
| 939 | "the ELF support compiled in."), |
| 940 | paddress (gdbarch, pc)); |
| 941 | } |
| 942 | |
| 943 | /* See elf_gnu_ifunc_resolve_name for its real implementation. */ |
| 944 | |
| 945 | static bool |
| 946 | stub_gnu_ifunc_resolve_name (const char *function_name, |
| 947 | CORE_ADDR *function_address_p) |
| 948 | { |
| 949 | error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without " |
| 950 | "the ELF support compiled in."), |
| 951 | function_name); |
| 952 | } |
| 953 | |
| 954 | /* See elf_gnu_ifunc_resolver_stop for its real implementation. */ |
| 955 | |
| 956 | static void |
| 957 | stub_gnu_ifunc_resolver_stop (struct breakpoint *b) |
| 958 | { |
| 959 | internal_error (__FILE__, __LINE__, |
| 960 | _("elf_gnu_ifunc_resolver_stop cannot be reached.")); |
| 961 | } |
| 962 | |
| 963 | /* See elf_gnu_ifunc_resolver_return_stop for its real implementation. */ |
| 964 | |
| 965 | static void |
| 966 | stub_gnu_ifunc_resolver_return_stop (struct breakpoint *b) |
| 967 | { |
| 968 | internal_error (__FILE__, __LINE__, |
| 969 | _("elf_gnu_ifunc_resolver_return_stop cannot be reached.")); |
| 970 | } |
| 971 | |
| 972 | /* See elf_gnu_ifunc_fns for its real implementation. */ |
| 973 | |
| 974 | static const struct gnu_ifunc_fns stub_gnu_ifunc_fns = |
| 975 | { |
| 976 | stub_gnu_ifunc_resolve_addr, |
| 977 | stub_gnu_ifunc_resolve_name, |
| 978 | stub_gnu_ifunc_resolver_stop, |
| 979 | stub_gnu_ifunc_resolver_return_stop, |
| 980 | }; |
| 981 | |
| 982 | /* A placeholder for &elf_gnu_ifunc_fns. */ |
| 983 | |
| 984 | const struct gnu_ifunc_fns *gnu_ifunc_fns_p = &stub_gnu_ifunc_fns; |
| 985 | |
| 986 | \f |
| 987 | |
| 988 | /* Return leading symbol character for a BFD. If BFD is NULL, |
| 989 | return the leading symbol character from the main objfile. */ |
| 990 | |
| 991 | static int |
| 992 | get_symbol_leading_char (bfd *abfd) |
| 993 | { |
| 994 | if (abfd != NULL) |
| 995 | return bfd_get_symbol_leading_char (abfd); |
| 996 | if (symfile_objfile != NULL && symfile_objfile->obfd != NULL) |
| 997 | return bfd_get_symbol_leading_char (symfile_objfile->obfd); |
| 998 | return 0; |
| 999 | } |
| 1000 | |
| 1001 | /* See minsyms.h. */ |
| 1002 | |
| 1003 | minimal_symbol_reader::minimal_symbol_reader (struct objfile *obj) |
| 1004 | : m_objfile (obj), |
| 1005 | m_msym_bunch (NULL), |
| 1006 | /* Note that presetting m_msym_bunch_index to BUNCH_SIZE causes the |
| 1007 | first call to save a minimal symbol to allocate the memory for |
| 1008 | the first bunch. */ |
| 1009 | m_msym_bunch_index (BUNCH_SIZE), |
| 1010 | m_msym_count (0) |
| 1011 | { |
| 1012 | } |
| 1013 | |
| 1014 | /* Discard the currently collected minimal symbols, if any. If we wish |
| 1015 | to save them for later use, we must have already copied them somewhere |
| 1016 | else before calling this function. */ |
| 1017 | |
| 1018 | minimal_symbol_reader::~minimal_symbol_reader () |
| 1019 | { |
| 1020 | struct msym_bunch *next; |
| 1021 | |
| 1022 | while (m_msym_bunch != NULL) |
| 1023 | { |
| 1024 | next = m_msym_bunch->next; |
| 1025 | xfree (m_msym_bunch); |
| 1026 | m_msym_bunch = next; |
| 1027 | } |
| 1028 | } |
| 1029 | |
| 1030 | /* See minsyms.h. */ |
| 1031 | |
| 1032 | void |
| 1033 | minimal_symbol_reader::record (const char *name, CORE_ADDR address, |
| 1034 | enum minimal_symbol_type ms_type) |
| 1035 | { |
| 1036 | int section; |
| 1037 | |
| 1038 | switch (ms_type) |
| 1039 | { |
| 1040 | case mst_text: |
| 1041 | case mst_text_gnu_ifunc: |
| 1042 | case mst_file_text: |
| 1043 | case mst_solib_trampoline: |
| 1044 | section = SECT_OFF_TEXT (m_objfile); |
| 1045 | break; |
| 1046 | case mst_data: |
| 1047 | case mst_data_gnu_ifunc: |
| 1048 | case mst_file_data: |
| 1049 | section = SECT_OFF_DATA (m_objfile); |
| 1050 | break; |
| 1051 | case mst_bss: |
| 1052 | case mst_file_bss: |
| 1053 | section = SECT_OFF_BSS (m_objfile); |
| 1054 | break; |
| 1055 | default: |
| 1056 | section = -1; |
| 1057 | } |
| 1058 | |
| 1059 | record_with_info (name, address, ms_type, section); |
| 1060 | } |
| 1061 | |
| 1062 | /* Convert an enumerator of type minimal_symbol_type to its string |
| 1063 | representation. */ |
| 1064 | |
| 1065 | static const char * |
| 1066 | mst_str (minimal_symbol_type t) |
| 1067 | { |
| 1068 | #define MST_TO_STR(x) case x: return #x; |
| 1069 | switch (t) |
| 1070 | { |
| 1071 | MST_TO_STR (mst_unknown); |
| 1072 | MST_TO_STR (mst_text); |
| 1073 | MST_TO_STR (mst_text_gnu_ifunc); |
| 1074 | MST_TO_STR (mst_slot_got_plt); |
| 1075 | MST_TO_STR (mst_data); |
| 1076 | MST_TO_STR (mst_bss); |
| 1077 | MST_TO_STR (mst_abs); |
| 1078 | MST_TO_STR (mst_solib_trampoline); |
| 1079 | MST_TO_STR (mst_file_text); |
| 1080 | MST_TO_STR (mst_file_data); |
| 1081 | MST_TO_STR (mst_file_bss); |
| 1082 | |
| 1083 | default: |
| 1084 | return "mst_???"; |
| 1085 | } |
| 1086 | #undef MST_TO_STR |
| 1087 | } |
| 1088 | |
| 1089 | /* See minsyms.h. */ |
| 1090 | |
| 1091 | struct minimal_symbol * |
| 1092 | minimal_symbol_reader::record_full (gdb::string_view name, |
| 1093 | bool copy_name, CORE_ADDR address, |
| 1094 | enum minimal_symbol_type ms_type, |
| 1095 | int section) |
| 1096 | { |
| 1097 | struct msym_bunch *newobj; |
| 1098 | struct minimal_symbol *msymbol; |
| 1099 | |
| 1100 | /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into |
| 1101 | the minimal symbols, because if there is also another symbol |
| 1102 | at the same address (e.g. the first function of the file), |
| 1103 | lookup_minimal_symbol_by_pc would have no way of getting the |
| 1104 | right one. */ |
| 1105 | if (ms_type == mst_file_text && name[0] == 'g' |
| 1106 | && (name == GCC_COMPILED_FLAG_SYMBOL |
| 1107 | || name == GCC2_COMPILED_FLAG_SYMBOL)) |
| 1108 | return (NULL); |
| 1109 | |
| 1110 | /* It's safe to strip the leading char here once, since the name |
| 1111 | is also stored stripped in the minimal symbol table. */ |
| 1112 | if (name[0] == get_symbol_leading_char (m_objfile->obfd)) |
| 1113 | name = name.substr (1); |
| 1114 | |
| 1115 | if (ms_type == mst_file_text && startswith (name, "__gnu_compiled")) |
| 1116 | return (NULL); |
| 1117 | |
| 1118 | if (symtab_create_debug >= 2) |
| 1119 | printf_unfiltered ("Recording minsym: %-21s %18s %4d %.*s\n", |
| 1120 | mst_str (ms_type), hex_string (address), section, |
| 1121 | (int) name.size (), name.data ()); |
| 1122 | |
| 1123 | if (m_msym_bunch_index == BUNCH_SIZE) |
| 1124 | { |
| 1125 | newobj = XCNEW (struct msym_bunch); |
| 1126 | m_msym_bunch_index = 0; |
| 1127 | newobj->next = m_msym_bunch; |
| 1128 | m_msym_bunch = newobj; |
| 1129 | } |
| 1130 | msymbol = &m_msym_bunch->contents[m_msym_bunch_index]; |
| 1131 | msymbol->set_language (language_auto, |
| 1132 | &m_objfile->per_bfd->storage_obstack); |
| 1133 | |
| 1134 | if (copy_name) |
| 1135 | msymbol->m_name = obstack_strndup (&m_objfile->per_bfd->storage_obstack, |
| 1136 | name.data (), name.size ()); |
| 1137 | else |
| 1138 | msymbol->m_name = name.data (); |
| 1139 | |
| 1140 | SET_MSYMBOL_VALUE_ADDRESS (msymbol, address); |
| 1141 | MSYMBOL_SECTION (msymbol) = section; |
| 1142 | |
| 1143 | MSYMBOL_TYPE (msymbol) = ms_type; |
| 1144 | |
| 1145 | /* If we already read minimal symbols for this objfile, then don't |
| 1146 | ever allocate a new one. */ |
| 1147 | if (!m_objfile->per_bfd->minsyms_read) |
| 1148 | { |
| 1149 | m_msym_bunch_index++; |
| 1150 | m_objfile->per_bfd->n_minsyms++; |
| 1151 | } |
| 1152 | m_msym_count++; |
| 1153 | return msymbol; |
| 1154 | } |
| 1155 | |
| 1156 | /* Compare two minimal symbols by address and return true if FN1's address |
| 1157 | is less than FN2's, so that we sort into unsigned numeric order. |
| 1158 | Within groups with the same address, sort by name. */ |
| 1159 | |
| 1160 | static inline bool |
| 1161 | minimal_symbol_is_less_than (const minimal_symbol &fn1, |
| 1162 | const minimal_symbol &fn2) |
| 1163 | { |
| 1164 | if (MSYMBOL_VALUE_RAW_ADDRESS (&fn1) < MSYMBOL_VALUE_RAW_ADDRESS (&fn2)) |
| 1165 | { |
| 1166 | return true; /* addr 1 is less than addr 2. */ |
| 1167 | } |
| 1168 | else if (MSYMBOL_VALUE_RAW_ADDRESS (&fn1) > MSYMBOL_VALUE_RAW_ADDRESS (&fn2)) |
| 1169 | { |
| 1170 | return false; /* addr 1 is greater than addr 2. */ |
| 1171 | } |
| 1172 | else |
| 1173 | /* addrs are equal: sort by name */ |
| 1174 | { |
| 1175 | const char *name1 = fn1.linkage_name (); |
| 1176 | const char *name2 = fn2.linkage_name (); |
| 1177 | |
| 1178 | if (name1 && name2) /* both have names */ |
| 1179 | return strcmp (name1, name2) < 0; |
| 1180 | else if (name2) |
| 1181 | return true; /* fn1 has no name, so it is "less". */ |
| 1182 | else if (name1) /* fn2 has no name, so it is "less". */ |
| 1183 | return false; |
| 1184 | else |
| 1185 | return false; /* Neither has a name, so they're equal. */ |
| 1186 | } |
| 1187 | } |
| 1188 | |
| 1189 | /* Compact duplicate entries out of a minimal symbol table by walking |
| 1190 | through the table and compacting out entries with duplicate addresses |
| 1191 | and matching names. Return the number of entries remaining. |
| 1192 | |
| 1193 | On entry, the table resides between msymbol[0] and msymbol[mcount]. |
| 1194 | On exit, it resides between msymbol[0] and msymbol[result_count]. |
| 1195 | |
| 1196 | When files contain multiple sources of symbol information, it is |
| 1197 | possible for the minimal symbol table to contain many duplicate entries. |
| 1198 | As an example, SVR4 systems use ELF formatted object files, which |
| 1199 | usually contain at least two different types of symbol tables (a |
| 1200 | standard ELF one and a smaller dynamic linking table), as well as |
| 1201 | DWARF debugging information for files compiled with -g. |
| 1202 | |
| 1203 | Without compacting, the minimal symbol table for gdb itself contains |
| 1204 | over a 1000 duplicates, about a third of the total table size. Aside |
| 1205 | from the potential trap of not noticing that two successive entries |
| 1206 | identify the same location, this duplication impacts the time required |
| 1207 | to linearly scan the table, which is done in a number of places. So we |
| 1208 | just do one linear scan here and toss out the duplicates. |
| 1209 | |
| 1210 | Since the different sources of information for each symbol may |
| 1211 | have different levels of "completeness", we may have duplicates |
| 1212 | that have one entry with type "mst_unknown" and the other with a |
| 1213 | known type. So if the one we are leaving alone has type mst_unknown, |
| 1214 | overwrite its type with the type from the one we are compacting out. */ |
| 1215 | |
| 1216 | static int |
| 1217 | compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount, |
| 1218 | struct objfile *objfile) |
| 1219 | { |
| 1220 | struct minimal_symbol *copyfrom; |
| 1221 | struct minimal_symbol *copyto; |
| 1222 | |
| 1223 | if (mcount > 0) |
| 1224 | { |
| 1225 | copyfrom = copyto = msymbol; |
| 1226 | while (copyfrom < msymbol + mcount - 1) |
| 1227 | { |
| 1228 | if (MSYMBOL_VALUE_RAW_ADDRESS (copyfrom) |
| 1229 | == MSYMBOL_VALUE_RAW_ADDRESS ((copyfrom + 1)) |
| 1230 | && MSYMBOL_SECTION (copyfrom) == MSYMBOL_SECTION (copyfrom + 1) |
| 1231 | && strcmp (copyfrom->linkage_name (), |
| 1232 | (copyfrom + 1)->linkage_name ()) == 0) |
| 1233 | { |
| 1234 | if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown) |
| 1235 | { |
| 1236 | MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom); |
| 1237 | } |
| 1238 | copyfrom++; |
| 1239 | } |
| 1240 | else |
| 1241 | *copyto++ = *copyfrom++; |
| 1242 | } |
| 1243 | *copyto++ = *copyfrom++; |
| 1244 | mcount = copyto - msymbol; |
| 1245 | } |
| 1246 | return (mcount); |
| 1247 | } |
| 1248 | |
| 1249 | static void |
| 1250 | clear_minimal_symbol_hash_tables (struct objfile *objfile) |
| 1251 | { |
| 1252 | for (size_t i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++) |
| 1253 | { |
| 1254 | objfile->per_bfd->msymbol_hash[i] = 0; |
| 1255 | objfile->per_bfd->msymbol_demangled_hash[i] = 0; |
| 1256 | } |
| 1257 | } |
| 1258 | |
| 1259 | /* This struct is used to store values we compute for msymbols on the |
| 1260 | background threads but don't need to keep around long term. */ |
| 1261 | struct computed_hash_values |
| 1262 | { |
| 1263 | /* Length of the linkage_name of the symbol. */ |
| 1264 | size_t name_length; |
| 1265 | /* Hash code (using fast_hash) of the linkage_name. */ |
| 1266 | hashval_t mangled_name_hash; |
| 1267 | /* The msymbol_hash of the linkage_name. */ |
| 1268 | unsigned int minsym_hash; |
| 1269 | /* The msymbol_hash of the search_name. */ |
| 1270 | unsigned int minsym_demangled_hash; |
| 1271 | }; |
| 1272 | |
| 1273 | /* Build (or rebuild) the minimal symbol hash tables. This is necessary |
| 1274 | after compacting or sorting the table since the entries move around |
| 1275 | thus causing the internal minimal_symbol pointers to become jumbled. */ |
| 1276 | |
| 1277 | static void |
| 1278 | build_minimal_symbol_hash_tables |
| 1279 | (struct objfile *objfile, |
| 1280 | const std::vector<computed_hash_values>& hash_values) |
| 1281 | { |
| 1282 | int i; |
| 1283 | struct minimal_symbol *msym; |
| 1284 | |
| 1285 | /* (Re)insert the actual entries. */ |
| 1286 | int mcount = objfile->per_bfd->minimal_symbol_count; |
| 1287 | for ((i = 0, |
| 1288 | msym = objfile->per_bfd->msymbols.get ()); |
| 1289 | i < mcount; |
| 1290 | i++, msym++) |
| 1291 | { |
| 1292 | msym->hash_next = 0; |
| 1293 | add_minsym_to_hash_table (msym, objfile->per_bfd->msymbol_hash, |
| 1294 | hash_values[i].minsym_hash); |
| 1295 | |
| 1296 | msym->demangled_hash_next = 0; |
| 1297 | if (msym->search_name () != msym->linkage_name ()) |
| 1298 | add_minsym_to_demangled_hash_table |
| 1299 | (msym, objfile, hash_values[i].minsym_demangled_hash); |
| 1300 | } |
| 1301 | } |
| 1302 | |
| 1303 | /* Add the minimal symbols in the existing bunches to the objfile's official |
| 1304 | minimal symbol table. In most cases there is no minimal symbol table yet |
| 1305 | for this objfile, and the existing bunches are used to create one. Once |
| 1306 | in a while (for shared libraries for example), we add symbols (e.g. common |
| 1307 | symbols) to an existing objfile. */ |
| 1308 | |
| 1309 | void |
| 1310 | minimal_symbol_reader::install () |
| 1311 | { |
| 1312 | int mcount; |
| 1313 | struct msym_bunch *bunch; |
| 1314 | struct minimal_symbol *msymbols; |
| 1315 | int alloc_count; |
| 1316 | |
| 1317 | if (m_objfile->per_bfd->minsyms_read) |
| 1318 | return; |
| 1319 | |
| 1320 | if (m_msym_count > 0) |
| 1321 | { |
| 1322 | if (symtab_create_debug) |
| 1323 | { |
| 1324 | fprintf_unfiltered (gdb_stdlog, |
| 1325 | "Installing %d minimal symbols of objfile %s.\n", |
| 1326 | m_msym_count, objfile_name (m_objfile)); |
| 1327 | } |
| 1328 | |
| 1329 | /* Allocate enough space, into which we will gather the bunches |
| 1330 | of new and existing minimal symbols, sort them, and then |
| 1331 | compact out the duplicate entries. Once we have a final |
| 1332 | table, we will give back the excess space. */ |
| 1333 | |
| 1334 | alloc_count = m_msym_count + m_objfile->per_bfd->minimal_symbol_count; |
| 1335 | gdb::unique_xmalloc_ptr<minimal_symbol> |
| 1336 | msym_holder (XNEWVEC (minimal_symbol, alloc_count)); |
| 1337 | msymbols = msym_holder.get (); |
| 1338 | |
| 1339 | /* Copy in the existing minimal symbols, if there are any. */ |
| 1340 | |
| 1341 | if (m_objfile->per_bfd->minimal_symbol_count) |
| 1342 | memcpy (msymbols, m_objfile->per_bfd->msymbols.get (), |
| 1343 | m_objfile->per_bfd->minimal_symbol_count |
| 1344 | * sizeof (struct minimal_symbol)); |
| 1345 | |
| 1346 | /* Walk through the list of minimal symbol bunches, adding each symbol |
| 1347 | to the new contiguous array of symbols. Note that we start with the |
| 1348 | current, possibly partially filled bunch (thus we use the current |
| 1349 | msym_bunch_index for the first bunch we copy over), and thereafter |
| 1350 | each bunch is full. */ |
| 1351 | |
| 1352 | mcount = m_objfile->per_bfd->minimal_symbol_count; |
| 1353 | |
| 1354 | for (bunch = m_msym_bunch; bunch != NULL; bunch = bunch->next) |
| 1355 | { |
| 1356 | memcpy (&msymbols[mcount], &bunch->contents[0], |
| 1357 | m_msym_bunch_index * sizeof (struct minimal_symbol)); |
| 1358 | mcount += m_msym_bunch_index; |
| 1359 | m_msym_bunch_index = BUNCH_SIZE; |
| 1360 | } |
| 1361 | |
| 1362 | /* Sort the minimal symbols by address. */ |
| 1363 | |
| 1364 | std::sort (msymbols, msymbols + mcount, minimal_symbol_is_less_than); |
| 1365 | |
| 1366 | /* Compact out any duplicates, and free up whatever space we are |
| 1367 | no longer using. */ |
| 1368 | |
| 1369 | mcount = compact_minimal_symbols (msymbols, mcount, m_objfile); |
| 1370 | msym_holder.reset (XRESIZEVEC (struct minimal_symbol, |
| 1371 | msym_holder.release (), |
| 1372 | mcount)); |
| 1373 | |
| 1374 | /* Attach the minimal symbol table to the specified objfile. |
| 1375 | The strings themselves are also located in the storage_obstack |
| 1376 | of this objfile. */ |
| 1377 | |
| 1378 | if (m_objfile->per_bfd->minimal_symbol_count != 0) |
| 1379 | clear_minimal_symbol_hash_tables (m_objfile); |
| 1380 | |
| 1381 | m_objfile->per_bfd->minimal_symbol_count = mcount; |
| 1382 | m_objfile->per_bfd->msymbols = std::move (msym_holder); |
| 1383 | |
| 1384 | #if CXX_STD_THREAD |
| 1385 | /* Mutex that is used when modifying or accessing the demangled |
| 1386 | hash table. */ |
| 1387 | std::mutex demangled_mutex; |
| 1388 | #endif |
| 1389 | |
| 1390 | std::vector<computed_hash_values> hash_values (mcount); |
| 1391 | |
| 1392 | msymbols = m_objfile->per_bfd->msymbols.get (); |
| 1393 | gdb::parallel_for_each |
| 1394 | (&msymbols[0], &msymbols[mcount], |
| 1395 | [&] (minimal_symbol *start, minimal_symbol *end) |
| 1396 | { |
| 1397 | for (minimal_symbol *msym = start; msym < end; ++msym) |
| 1398 | { |
| 1399 | size_t idx = msym - msymbols; |
| 1400 | hash_values[idx].name_length = strlen (msym->linkage_name ()); |
| 1401 | if (!msym->name_set) |
| 1402 | { |
| 1403 | /* This will be freed later, by compute_and_set_names. */ |
| 1404 | char *demangled_name |
| 1405 | = symbol_find_demangled_name (msym, msym->linkage_name ()); |
| 1406 | symbol_set_demangled_name |
| 1407 | (msym, demangled_name, |
| 1408 | &m_objfile->per_bfd->storage_obstack); |
| 1409 | msym->name_set = 1; |
| 1410 | } |
| 1411 | /* This mangled_name_hash computation has to be outside of |
| 1412 | the name_set check, or compute_and_set_names below will |
| 1413 | be called with an invalid hash value. */ |
| 1414 | hash_values[idx].mangled_name_hash |
| 1415 | = fast_hash (msym->linkage_name (), |
| 1416 | hash_values[idx].name_length); |
| 1417 | hash_values[idx].minsym_hash |
| 1418 | = msymbol_hash (msym->linkage_name ()); |
| 1419 | /* We only use this hash code if the search name differs |
| 1420 | from the linkage name. See the code in |
| 1421 | build_minimal_symbol_hash_tables. */ |
| 1422 | if (msym->search_name () != msym->linkage_name ()) |
| 1423 | hash_values[idx].minsym_demangled_hash |
| 1424 | = search_name_hash (msym->language (), msym->search_name ()); |
| 1425 | } |
| 1426 | { |
| 1427 | /* To limit how long we hold the lock, we only acquire it here |
| 1428 | and not while we demangle the names above. */ |
| 1429 | #if CXX_STD_THREAD |
| 1430 | std::lock_guard<std::mutex> guard (demangled_mutex); |
| 1431 | #endif |
| 1432 | for (minimal_symbol *msym = start; msym < end; ++msym) |
| 1433 | { |
| 1434 | size_t idx = msym - msymbols; |
| 1435 | msym->compute_and_set_names |
| 1436 | (gdb::string_view (msym->linkage_name (), |
| 1437 | hash_values[idx].name_length), |
| 1438 | false, |
| 1439 | m_objfile->per_bfd, |
| 1440 | hash_values[idx].mangled_name_hash); |
| 1441 | } |
| 1442 | } |
| 1443 | }); |
| 1444 | |
| 1445 | build_minimal_symbol_hash_tables (m_objfile, hash_values); |
| 1446 | } |
| 1447 | } |
| 1448 | |
| 1449 | /* Check if PC is in a shared library trampoline code stub. |
| 1450 | Return minimal symbol for the trampoline entry or NULL if PC is not |
| 1451 | in a trampoline code stub. */ |
| 1452 | |
| 1453 | static struct minimal_symbol * |
| 1454 | lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc) |
| 1455 | { |
| 1456 | bound_minimal_symbol msymbol |
| 1457 | = lookup_minimal_symbol_by_pc_section (pc, NULL, |
| 1458 | lookup_msym_prefer::TRAMPOLINE); |
| 1459 | |
| 1460 | if (msymbol.minsym != NULL |
| 1461 | && MSYMBOL_TYPE (msymbol.minsym) == mst_solib_trampoline) |
| 1462 | return msymbol.minsym; |
| 1463 | return NULL; |
| 1464 | } |
| 1465 | |
| 1466 | /* If PC is in a shared library trampoline code stub, return the |
| 1467 | address of the `real' function belonging to the stub. |
| 1468 | Return 0 if PC is not in a trampoline code stub or if the real |
| 1469 | function is not found in the minimal symbol table. |
| 1470 | |
| 1471 | We may fail to find the right function if a function with the |
| 1472 | same name is defined in more than one shared library, but this |
| 1473 | is considered bad programming style. We could return 0 if we find |
| 1474 | a duplicate function in case this matters someday. */ |
| 1475 | |
| 1476 | CORE_ADDR |
| 1477 | find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc) |
| 1478 | { |
| 1479 | struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc); |
| 1480 | |
| 1481 | if (tsymbol != NULL) |
| 1482 | { |
| 1483 | for (objfile *objfile : current_program_space->objfiles ()) |
| 1484 | { |
| 1485 | for (minimal_symbol *msymbol : objfile->msymbols ()) |
| 1486 | { |
| 1487 | /* Also handle minimal symbols pointing to function |
| 1488 | descriptors. */ |
| 1489 | if ((MSYMBOL_TYPE (msymbol) == mst_text |
| 1490 | || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc |
| 1491 | || MSYMBOL_TYPE (msymbol) == mst_data |
| 1492 | || MSYMBOL_TYPE (msymbol) == mst_data_gnu_ifunc) |
| 1493 | && strcmp (msymbol->linkage_name (), |
| 1494 | tsymbol->linkage_name ()) == 0) |
| 1495 | { |
| 1496 | CORE_ADDR func; |
| 1497 | |
| 1498 | /* Ignore data symbols that are not function |
| 1499 | descriptors. */ |
| 1500 | if (msymbol_is_function (objfile, msymbol, &func)) |
| 1501 | return func; |
| 1502 | } |
| 1503 | } |
| 1504 | } |
| 1505 | } |
| 1506 | return 0; |
| 1507 | } |
| 1508 | |
| 1509 | /* See minsyms.h. */ |
| 1510 | |
| 1511 | CORE_ADDR |
| 1512 | minimal_symbol_upper_bound (struct bound_minimal_symbol minsym) |
| 1513 | { |
| 1514 | short section; |
| 1515 | struct obj_section *obj_section; |
| 1516 | CORE_ADDR result; |
| 1517 | struct minimal_symbol *iter, *msymbol; |
| 1518 | |
| 1519 | gdb_assert (minsym.minsym != NULL); |
| 1520 | |
| 1521 | /* If the minimal symbol has a size, use it. Otherwise use the |
| 1522 | lesser of the next minimal symbol in the same section, or the end |
| 1523 | of the section, as the end of the function. */ |
| 1524 | |
| 1525 | if (MSYMBOL_SIZE (minsym.minsym) != 0) |
| 1526 | return BMSYMBOL_VALUE_ADDRESS (minsym) + MSYMBOL_SIZE (minsym.minsym); |
| 1527 | |
| 1528 | /* Step over other symbols at this same address, and symbols in |
| 1529 | other sections, to find the next symbol in this section with a |
| 1530 | different address. */ |
| 1531 | |
| 1532 | struct minimal_symbol *past_the_end |
| 1533 | = (minsym.objfile->per_bfd->msymbols.get () |
| 1534 | + minsym.objfile->per_bfd->minimal_symbol_count); |
| 1535 | msymbol = minsym.minsym; |
| 1536 | section = MSYMBOL_SECTION (msymbol); |
| 1537 | for (iter = msymbol + 1; iter != past_the_end; ++iter) |
| 1538 | { |
| 1539 | if ((MSYMBOL_VALUE_RAW_ADDRESS (iter) |
| 1540 | != MSYMBOL_VALUE_RAW_ADDRESS (msymbol)) |
| 1541 | && MSYMBOL_SECTION (iter) == section) |
| 1542 | break; |
| 1543 | } |
| 1544 | |
| 1545 | obj_section = MSYMBOL_OBJ_SECTION (minsym.objfile, minsym.minsym); |
| 1546 | if (iter != past_the_end |
| 1547 | && (MSYMBOL_VALUE_ADDRESS (minsym.objfile, iter) |
| 1548 | < obj_section_endaddr (obj_section))) |
| 1549 | result = MSYMBOL_VALUE_ADDRESS (minsym.objfile, iter); |
| 1550 | else |
| 1551 | /* We got the start address from the last msymbol in the objfile. |
| 1552 | So the end address is the end of the section. */ |
| 1553 | result = obj_section_endaddr (obj_section); |
| 1554 | |
| 1555 | return result; |
| 1556 | } |