| 1 | /* GDB routines for manipulating the minimal symbol tables. |
| 2 | Copyright (C) 1992-2018 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 "symbol.h" |
| 54 | #include <algorithm> |
| 55 | #include "safe-ctype.h" |
| 56 | |
| 57 | /* See minsyms.h. */ |
| 58 | |
| 59 | bool |
| 60 | msymbol_is_function (struct objfile *objfile, minimal_symbol *minsym, |
| 61 | CORE_ADDR *func_address_p) |
| 62 | { |
| 63 | CORE_ADDR msym_addr = MSYMBOL_VALUE_ADDRESS (objfile, minsym); |
| 64 | |
| 65 | switch (minsym->type) |
| 66 | { |
| 67 | case mst_slot_got_plt: |
| 68 | case mst_data: |
| 69 | case mst_bss: |
| 70 | case mst_abs: |
| 71 | case mst_file_data: |
| 72 | case mst_file_bss: |
| 73 | case mst_data_gnu_ifunc: |
| 74 | { |
| 75 | struct gdbarch *gdbarch = get_objfile_arch (objfile); |
| 76 | CORE_ADDR pc = gdbarch_convert_from_func_ptr_addr (gdbarch, msym_addr, |
| 77 | target_stack); |
| 78 | if (pc != msym_addr) |
| 79 | { |
| 80 | if (func_address_p != NULL) |
| 81 | *func_address_p = pc; |
| 82 | return true; |
| 83 | } |
| 84 | return false; |
| 85 | } |
| 86 | default: |
| 87 | if (func_address_p != NULL) |
| 88 | *func_address_p = msym_addr; |
| 89 | return true; |
| 90 | } |
| 91 | } |
| 92 | |
| 93 | /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE. |
| 94 | At the end, copy them all into one newly allocated location on an objfile's |
| 95 | per-BFD storage obstack. */ |
| 96 | |
| 97 | #define BUNCH_SIZE 127 |
| 98 | |
| 99 | struct msym_bunch |
| 100 | { |
| 101 | struct msym_bunch *next; |
| 102 | struct minimal_symbol contents[BUNCH_SIZE]; |
| 103 | }; |
| 104 | |
| 105 | /* See minsyms.h. */ |
| 106 | |
| 107 | unsigned int |
| 108 | msymbol_hash_iw (const char *string) |
| 109 | { |
| 110 | unsigned int hash = 0; |
| 111 | |
| 112 | while (*string && *string != '(') |
| 113 | { |
| 114 | string = skip_spaces (string); |
| 115 | if (*string && *string != '(') |
| 116 | { |
| 117 | hash = SYMBOL_HASH_NEXT (hash, *string); |
| 118 | ++string; |
| 119 | } |
| 120 | } |
| 121 | return hash; |
| 122 | } |
| 123 | |
| 124 | /* See minsyms.h. */ |
| 125 | |
| 126 | unsigned int |
| 127 | msymbol_hash (const char *string) |
| 128 | { |
| 129 | unsigned int hash = 0; |
| 130 | |
| 131 | for (; *string; ++string) |
| 132 | hash = SYMBOL_HASH_NEXT (hash, *string); |
| 133 | return hash; |
| 134 | } |
| 135 | |
| 136 | /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE. */ |
| 137 | static void |
| 138 | add_minsym_to_hash_table (struct minimal_symbol *sym, |
| 139 | struct minimal_symbol **table) |
| 140 | { |
| 141 | if (sym->hash_next == NULL) |
| 142 | { |
| 143 | unsigned int hash |
| 144 | = msymbol_hash (MSYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE; |
| 145 | |
| 146 | sym->hash_next = table[hash]; |
| 147 | table[hash] = sym; |
| 148 | } |
| 149 | } |
| 150 | |
| 151 | /* Add the minimal symbol SYM to an objfile's minsym demangled hash table, |
| 152 | TABLE. */ |
| 153 | static void |
| 154 | add_minsym_to_demangled_hash_table (struct minimal_symbol *sym, |
| 155 | struct objfile *objfile) |
| 156 | { |
| 157 | if (sym->demangled_hash_next == NULL) |
| 158 | { |
| 159 | unsigned int hash = search_name_hash (MSYMBOL_LANGUAGE (sym), |
| 160 | MSYMBOL_SEARCH_NAME (sym)); |
| 161 | |
| 162 | auto &vec = objfile->per_bfd->demangled_hash_languages; |
| 163 | auto it = std::lower_bound (vec.begin (), vec.end (), |
| 164 | MSYMBOL_LANGUAGE (sym)); |
| 165 | if (it == vec.end () || *it != MSYMBOL_LANGUAGE (sym)) |
| 166 | vec.insert (it, MSYMBOL_LANGUAGE (sym)); |
| 167 | |
| 168 | struct minimal_symbol **table |
| 169 | = objfile->per_bfd->msymbol_demangled_hash; |
| 170 | unsigned int hash_index = hash % MINIMAL_SYMBOL_HASH_SIZE; |
| 171 | sym->demangled_hash_next = table[hash_index]; |
| 172 | table[hash_index] = sym; |
| 173 | } |
| 174 | } |
| 175 | |
| 176 | /* Worker object for lookup_minimal_symbol. Stores temporary results |
| 177 | while walking the symbol tables. */ |
| 178 | |
| 179 | struct found_minimal_symbols |
| 180 | { |
| 181 | /* External symbols are best. */ |
| 182 | bound_minimal_symbol external_symbol {}; |
| 183 | |
| 184 | /* File-local symbols are next best. */ |
| 185 | bound_minimal_symbol file_symbol {}; |
| 186 | |
| 187 | /* Symbols for shared library trampolines are next best. */ |
| 188 | bound_minimal_symbol trampoline_symbol {}; |
| 189 | |
| 190 | /* Called when a symbol name matches. Check if the minsym is a |
| 191 | better type than what we had already found, and record it in one |
| 192 | of the members fields if so. Returns true if we collected the |
| 193 | real symbol, in which case we can stop searching. */ |
| 194 | bool maybe_collect (const char *sfile, objfile *objf, |
| 195 | minimal_symbol *msymbol); |
| 196 | }; |
| 197 | |
| 198 | /* See declaration above. */ |
| 199 | |
| 200 | bool |
| 201 | found_minimal_symbols::maybe_collect (const char *sfile, |
| 202 | struct objfile *objfile, |
| 203 | minimal_symbol *msymbol) |
| 204 | { |
| 205 | switch (MSYMBOL_TYPE (msymbol)) |
| 206 | { |
| 207 | case mst_file_text: |
| 208 | case mst_file_data: |
| 209 | case mst_file_bss: |
| 210 | if (sfile == NULL |
| 211 | || filename_cmp (msymbol->filename, sfile) == 0) |
| 212 | { |
| 213 | file_symbol.minsym = msymbol; |
| 214 | file_symbol.objfile = objfile; |
| 215 | } |
| 216 | break; |
| 217 | |
| 218 | case mst_solib_trampoline: |
| 219 | |
| 220 | /* If a trampoline symbol is found, we prefer to keep |
| 221 | looking for the *real* symbol. If the actual symbol |
| 222 | is not found, then we'll use the trampoline |
| 223 | entry. */ |
| 224 | if (trampoline_symbol.minsym == NULL) |
| 225 | { |
| 226 | trampoline_symbol.minsym = msymbol; |
| 227 | trampoline_symbol.objfile = objfile; |
| 228 | } |
| 229 | break; |
| 230 | |
| 231 | case mst_unknown: |
| 232 | default: |
| 233 | external_symbol.minsym = msymbol; |
| 234 | external_symbol.objfile = objfile; |
| 235 | /* We have the real symbol. No use looking further. */ |
| 236 | return true; |
| 237 | } |
| 238 | |
| 239 | /* Keep looking. */ |
| 240 | return false; |
| 241 | } |
| 242 | |
| 243 | /* Walk the mangled name hash table, and pass each symbol whose name |
| 244 | matches LOOKUP_NAME according to NAMECMP to FOUND. */ |
| 245 | |
| 246 | static void |
| 247 | lookup_minimal_symbol_mangled (const char *lookup_name, |
| 248 | const char *sfile, |
| 249 | struct objfile *objfile, |
| 250 | struct minimal_symbol **table, |
| 251 | unsigned int hash, |
| 252 | int (*namecmp) (const char *, const char *), |
| 253 | found_minimal_symbols &found) |
| 254 | { |
| 255 | for (minimal_symbol *msymbol = table[hash]; |
| 256 | msymbol != NULL; |
| 257 | msymbol = msymbol->hash_next) |
| 258 | { |
| 259 | const char *symbol_name = MSYMBOL_LINKAGE_NAME (msymbol); |
| 260 | |
| 261 | if (namecmp (symbol_name, lookup_name) == 0 |
| 262 | && found.maybe_collect (sfile, objfile, msymbol)) |
| 263 | return; |
| 264 | } |
| 265 | } |
| 266 | |
| 267 | /* Walk the demangled name hash table, and pass each symbol whose name |
| 268 | matches LOOKUP_NAME according to MATCHER to FOUND. */ |
| 269 | |
| 270 | static void |
| 271 | lookup_minimal_symbol_demangled (const lookup_name_info &lookup_name, |
| 272 | const char *sfile, |
| 273 | struct objfile *objfile, |
| 274 | struct minimal_symbol **table, |
| 275 | unsigned int hash, |
| 276 | symbol_name_matcher_ftype *matcher, |
| 277 | found_minimal_symbols &found) |
| 278 | { |
| 279 | for (minimal_symbol *msymbol = table[hash]; |
| 280 | msymbol != NULL; |
| 281 | msymbol = msymbol->demangled_hash_next) |
| 282 | { |
| 283 | const char *symbol_name = MSYMBOL_SEARCH_NAME (msymbol); |
| 284 | |
| 285 | if (matcher (symbol_name, lookup_name, NULL) |
| 286 | && found.maybe_collect (sfile, objfile, msymbol)) |
| 287 | return; |
| 288 | } |
| 289 | } |
| 290 | |
| 291 | /* Look through all the current minimal symbol tables and find the |
| 292 | first minimal symbol that matches NAME. If OBJF is non-NULL, limit |
| 293 | the search to that objfile. If SFILE is non-NULL, the only file-scope |
| 294 | symbols considered will be from that source file (global symbols are |
| 295 | still preferred). Returns a pointer to the minimal symbol that |
| 296 | matches, or NULL if no match is found. |
| 297 | |
| 298 | Note: One instance where there may be duplicate minimal symbols with |
| 299 | the same name is when the symbol tables for a shared library and the |
| 300 | symbol tables for an executable contain global symbols with the same |
| 301 | names (the dynamic linker deals with the duplication). |
| 302 | |
| 303 | It's also possible to have minimal symbols with different mangled |
| 304 | names, but identical demangled names. For example, the GNU C++ v3 |
| 305 | ABI requires the generation of two (or perhaps three) copies of |
| 306 | constructor functions --- "in-charge", "not-in-charge", and |
| 307 | "allocate" copies; destructors may be duplicated as well. |
| 308 | Obviously, there must be distinct mangled names for each of these, |
| 309 | but the demangled names are all the same: S::S or S::~S. */ |
| 310 | |
| 311 | struct bound_minimal_symbol |
| 312 | lookup_minimal_symbol (const char *name, const char *sfile, |
| 313 | struct objfile *objf) |
| 314 | { |
| 315 | struct objfile *objfile; |
| 316 | found_minimal_symbols found; |
| 317 | |
| 318 | unsigned int mangled_hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE; |
| 319 | |
| 320 | auto *mangled_cmp |
| 321 | = (case_sensitivity == case_sensitive_on |
| 322 | ? strcmp |
| 323 | : strcasecmp); |
| 324 | |
| 325 | if (sfile != NULL) |
| 326 | sfile = lbasename (sfile); |
| 327 | |
| 328 | lookup_name_info lookup_name (name, symbol_name_match_type::FULL); |
| 329 | |
| 330 | for (objfile = object_files; |
| 331 | objfile != NULL && found.external_symbol.minsym == NULL; |
| 332 | objfile = objfile->next) |
| 333 | { |
| 334 | if (objf == NULL || objf == objfile |
| 335 | || objf == objfile->separate_debug_objfile_backlink) |
| 336 | { |
| 337 | if (symbol_lookup_debug) |
| 338 | { |
| 339 | fprintf_unfiltered (gdb_stdlog, |
| 340 | "lookup_minimal_symbol (%s, %s, %s)\n", |
| 341 | name, sfile != NULL ? sfile : "NULL", |
| 342 | objfile_debug_name (objfile)); |
| 343 | } |
| 344 | |
| 345 | /* Do two passes: the first over the ordinary hash table, |
| 346 | and the second over the demangled hash table. */ |
| 347 | lookup_minimal_symbol_mangled (name, sfile, objfile, |
| 348 | objfile->per_bfd->msymbol_hash, |
| 349 | mangled_hash, mangled_cmp, found); |
| 350 | |
| 351 | /* If not found, try the demangled hash table. */ |
| 352 | if (found.external_symbol.minsym == NULL) |
| 353 | { |
| 354 | /* Once for each language in the demangled hash names |
| 355 | table (usually just zero or one languages). */ |
| 356 | for (auto lang : objfile->per_bfd->demangled_hash_languages) |
| 357 | { |
| 358 | unsigned int hash |
| 359 | = (lookup_name.search_name_hash (lang) |
| 360 | % MINIMAL_SYMBOL_HASH_SIZE); |
| 361 | |
| 362 | symbol_name_matcher_ftype *match |
| 363 | = get_symbol_name_matcher (language_def (lang), |
| 364 | lookup_name); |
| 365 | struct minimal_symbol **msymbol_demangled_hash |
| 366 | = objfile->per_bfd->msymbol_demangled_hash; |
| 367 | |
| 368 | lookup_minimal_symbol_demangled (lookup_name, sfile, objfile, |
| 369 | msymbol_demangled_hash, |
| 370 | hash, match, found); |
| 371 | |
| 372 | if (found.external_symbol.minsym != NULL) |
| 373 | break; |
| 374 | } |
| 375 | } |
| 376 | } |
| 377 | } |
| 378 | |
| 379 | /* External symbols are best. */ |
| 380 | if (found.external_symbol.minsym != NULL) |
| 381 | { |
| 382 | if (symbol_lookup_debug) |
| 383 | { |
| 384 | minimal_symbol *minsym = found.external_symbol.minsym; |
| 385 | |
| 386 | fprintf_unfiltered (gdb_stdlog, |
| 387 | "lookup_minimal_symbol (...) = %s (external)\n", |
| 388 | host_address_to_string (minsym)); |
| 389 | } |
| 390 | return found.external_symbol; |
| 391 | } |
| 392 | |
| 393 | /* File-local symbols are next best. */ |
| 394 | if (found.file_symbol.minsym != NULL) |
| 395 | { |
| 396 | if (symbol_lookup_debug) |
| 397 | { |
| 398 | minimal_symbol *minsym = found.file_symbol.minsym; |
| 399 | |
| 400 | fprintf_unfiltered (gdb_stdlog, |
| 401 | "lookup_minimal_symbol (...) = %s (file-local)\n", |
| 402 | host_address_to_string (minsym)); |
| 403 | } |
| 404 | return found.file_symbol; |
| 405 | } |
| 406 | |
| 407 | /* Symbols for shared library trampolines are next best. */ |
| 408 | if (found.trampoline_symbol.minsym != NULL) |
| 409 | { |
| 410 | if (symbol_lookup_debug) |
| 411 | { |
| 412 | minimal_symbol *minsym = found.trampoline_symbol.minsym; |
| 413 | |
| 414 | fprintf_unfiltered (gdb_stdlog, |
| 415 | "lookup_minimal_symbol (...) = %s (trampoline)\n", |
| 416 | host_address_to_string (minsym)); |
| 417 | } |
| 418 | |
| 419 | return found.trampoline_symbol; |
| 420 | } |
| 421 | |
| 422 | /* Not found. */ |
| 423 | if (symbol_lookup_debug) |
| 424 | fprintf_unfiltered (gdb_stdlog, "lookup_minimal_symbol (...) = NULL\n"); |
| 425 | return {}; |
| 426 | } |
| 427 | |
| 428 | /* See minsyms.h. */ |
| 429 | |
| 430 | struct bound_minimal_symbol |
| 431 | lookup_bound_minimal_symbol (const char *name) |
| 432 | { |
| 433 | return lookup_minimal_symbol (name, NULL, NULL); |
| 434 | } |
| 435 | |
| 436 | /* See common/symbol.h. */ |
| 437 | |
| 438 | int |
| 439 | find_minimal_symbol_address (const char *name, CORE_ADDR *addr, |
| 440 | struct objfile *objfile) |
| 441 | { |
| 442 | struct bound_minimal_symbol sym |
| 443 | = lookup_minimal_symbol (name, NULL, objfile); |
| 444 | |
| 445 | if (sym.minsym != NULL) |
| 446 | *addr = BMSYMBOL_VALUE_ADDRESS (sym); |
| 447 | |
| 448 | return sym.minsym == NULL; |
| 449 | } |
| 450 | |
| 451 | /* Get the lookup name form best suitable for linkage name |
| 452 | matching. */ |
| 453 | |
| 454 | static const char * |
| 455 | linkage_name_str (const lookup_name_info &lookup_name) |
| 456 | { |
| 457 | /* Unlike most languages (including C++), Ada uses the |
| 458 | encoded/linkage name as the search name recorded in symbols. So |
| 459 | if debugging in Ada mode, prefer the Ada-encoded name. This also |
| 460 | makes Ada's verbatim match syntax ("<...>") work, because |
| 461 | "lookup_name.name()" includes the "<>"s, while |
| 462 | "lookup_name.ada().lookup_name()" is the encoded name with "<>"s |
| 463 | stripped. */ |
| 464 | if (current_language->la_language == language_ada) |
| 465 | return lookup_name.ada ().lookup_name ().c_str (); |
| 466 | |
| 467 | return lookup_name.name ().c_str (); |
| 468 | } |
| 469 | |
| 470 | /* See minsyms.h. */ |
| 471 | |
| 472 | void |
| 473 | iterate_over_minimal_symbols |
| 474 | (struct objfile *objf, const lookup_name_info &lookup_name, |
| 475 | gdb::function_view<bool (struct minimal_symbol *)> callback) |
| 476 | { |
| 477 | /* The first pass is over the ordinary hash table. */ |
| 478 | { |
| 479 | const char *name = linkage_name_str (lookup_name); |
| 480 | unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE; |
| 481 | auto *mangled_cmp |
| 482 | = (case_sensitivity == case_sensitive_on |
| 483 | ? strcmp |
| 484 | : strcasecmp); |
| 485 | |
| 486 | for (minimal_symbol *iter = objf->per_bfd->msymbol_hash[hash]; |
| 487 | iter != NULL; |
| 488 | iter = iter->hash_next) |
| 489 | { |
| 490 | if (mangled_cmp (MSYMBOL_LINKAGE_NAME (iter), name) == 0) |
| 491 | if (callback (iter)) |
| 492 | return; |
| 493 | } |
| 494 | } |
| 495 | |
| 496 | /* The second pass is over the demangled table. Once for each |
| 497 | language in the demangled hash names table (usually just zero or |
| 498 | one). */ |
| 499 | for (auto lang : objf->per_bfd->demangled_hash_languages) |
| 500 | { |
| 501 | const language_defn *lang_def = language_def (lang); |
| 502 | symbol_name_matcher_ftype *name_match |
| 503 | = get_symbol_name_matcher (lang_def, lookup_name); |
| 504 | |
| 505 | unsigned int hash |
| 506 | = lookup_name.search_name_hash (lang) % MINIMAL_SYMBOL_HASH_SIZE; |
| 507 | for (minimal_symbol *iter = objf->per_bfd->msymbol_demangled_hash[hash]; |
| 508 | iter != NULL; |
| 509 | iter = iter->demangled_hash_next) |
| 510 | if (name_match (MSYMBOL_SEARCH_NAME (iter), lookup_name, NULL)) |
| 511 | if (callback (iter)) |
| 512 | return; |
| 513 | } |
| 514 | } |
| 515 | |
| 516 | /* See minsyms.h. */ |
| 517 | |
| 518 | struct bound_minimal_symbol |
| 519 | lookup_minimal_symbol_text (const char *name, struct objfile *objf) |
| 520 | { |
| 521 | struct objfile *objfile; |
| 522 | struct minimal_symbol *msymbol; |
| 523 | struct bound_minimal_symbol found_symbol = { NULL, NULL }; |
| 524 | struct bound_minimal_symbol found_file_symbol = { NULL, NULL }; |
| 525 | |
| 526 | unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE; |
| 527 | |
| 528 | for (objfile = object_files; |
| 529 | objfile != NULL && found_symbol.minsym == NULL; |
| 530 | objfile = objfile->next) |
| 531 | { |
| 532 | if (objf == NULL || objf == objfile |
| 533 | || objf == objfile->separate_debug_objfile_backlink) |
| 534 | { |
| 535 | for (msymbol = objfile->per_bfd->msymbol_hash[hash]; |
| 536 | msymbol != NULL && found_symbol.minsym == NULL; |
| 537 | msymbol = msymbol->hash_next) |
| 538 | { |
| 539 | if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 && |
| 540 | (MSYMBOL_TYPE (msymbol) == mst_text |
| 541 | || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc |
| 542 | || MSYMBOL_TYPE (msymbol) == mst_file_text)) |
| 543 | { |
| 544 | switch (MSYMBOL_TYPE (msymbol)) |
| 545 | { |
| 546 | case mst_file_text: |
| 547 | found_file_symbol.minsym = msymbol; |
| 548 | found_file_symbol.objfile = objfile; |
| 549 | break; |
| 550 | default: |
| 551 | found_symbol.minsym = msymbol; |
| 552 | found_symbol.objfile = objfile; |
| 553 | break; |
| 554 | } |
| 555 | } |
| 556 | } |
| 557 | } |
| 558 | } |
| 559 | /* External symbols are best. */ |
| 560 | if (found_symbol.minsym) |
| 561 | return found_symbol; |
| 562 | |
| 563 | /* File-local symbols are next best. */ |
| 564 | return found_file_symbol; |
| 565 | } |
| 566 | |
| 567 | /* See minsyms.h. */ |
| 568 | |
| 569 | struct minimal_symbol * |
| 570 | lookup_minimal_symbol_by_pc_name (CORE_ADDR pc, const char *name, |
| 571 | struct objfile *objf) |
| 572 | { |
| 573 | struct objfile *objfile; |
| 574 | struct minimal_symbol *msymbol; |
| 575 | |
| 576 | unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE; |
| 577 | |
| 578 | for (objfile = object_files; |
| 579 | objfile != NULL; |
| 580 | objfile = objfile->next) |
| 581 | { |
| 582 | if (objf == NULL || objf == objfile |
| 583 | || objf == objfile->separate_debug_objfile_backlink) |
| 584 | { |
| 585 | for (msymbol = objfile->per_bfd->msymbol_hash[hash]; |
| 586 | msymbol != NULL; |
| 587 | msymbol = msymbol->hash_next) |
| 588 | { |
| 589 | if (MSYMBOL_VALUE_ADDRESS (objfile, msymbol) == pc |
| 590 | && strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0) |
| 591 | return msymbol; |
| 592 | } |
| 593 | } |
| 594 | } |
| 595 | |
| 596 | return NULL; |
| 597 | } |
| 598 | |
| 599 | /* See minsyms.h. */ |
| 600 | |
| 601 | struct bound_minimal_symbol |
| 602 | lookup_minimal_symbol_solib_trampoline (const char *name, |
| 603 | struct objfile *objf) |
| 604 | { |
| 605 | struct objfile *objfile; |
| 606 | struct minimal_symbol *msymbol; |
| 607 | struct bound_minimal_symbol found_symbol = { NULL, NULL }; |
| 608 | |
| 609 | unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE; |
| 610 | |
| 611 | for (objfile = object_files; |
| 612 | objfile != NULL; |
| 613 | objfile = objfile->next) |
| 614 | { |
| 615 | if (objf == NULL || objf == objfile |
| 616 | || objf == objfile->separate_debug_objfile_backlink) |
| 617 | { |
| 618 | for (msymbol = objfile->per_bfd->msymbol_hash[hash]; |
| 619 | msymbol != NULL; |
| 620 | msymbol = msymbol->hash_next) |
| 621 | { |
| 622 | if (strcmp (MSYMBOL_LINKAGE_NAME (msymbol), name) == 0 && |
| 623 | MSYMBOL_TYPE (msymbol) == mst_solib_trampoline) |
| 624 | { |
| 625 | found_symbol.objfile = objfile; |
| 626 | found_symbol.minsym = msymbol; |
| 627 | return found_symbol; |
| 628 | } |
| 629 | } |
| 630 | } |
| 631 | } |
| 632 | |
| 633 | return found_symbol; |
| 634 | } |
| 635 | |
| 636 | /* A helper function that makes *PC section-relative. This searches |
| 637 | the sections of OBJFILE and if *PC is in a section, it subtracts |
| 638 | the section offset and returns true. Otherwise it returns |
| 639 | false. */ |
| 640 | |
| 641 | static int |
| 642 | frob_address (struct objfile *objfile, CORE_ADDR *pc) |
| 643 | { |
| 644 | struct obj_section *iter; |
| 645 | |
| 646 | ALL_OBJFILE_OSECTIONS (objfile, iter) |
| 647 | { |
| 648 | if (*pc >= obj_section_addr (iter) && *pc < obj_section_endaddr (iter)) |
| 649 | { |
| 650 | *pc -= obj_section_offset (iter); |
| 651 | return 1; |
| 652 | } |
| 653 | } |
| 654 | |
| 655 | return 0; |
| 656 | } |
| 657 | |
| 658 | /* Search through the minimal symbol table for each objfile and find |
| 659 | the symbol whose address is the largest address that is still less |
| 660 | than or equal to PC, and matches SECTION (which is not NULL). |
| 661 | Returns a pointer to the minimal symbol if such a symbol is found, |
| 662 | or NULL if PC is not in a suitable range. |
| 663 | Note that we need to look through ALL the minimal symbol tables |
| 664 | before deciding on the symbol that comes closest to the specified PC. |
| 665 | This is because objfiles can overlap, for example objfile A has .text |
| 666 | at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and |
| 667 | .data at 0x40048. |
| 668 | |
| 669 | If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when |
| 670 | there are text and trampoline symbols at the same address. |
| 671 | Otherwise prefer mst_text symbols. */ |
| 672 | |
| 673 | bound_minimal_symbol |
| 674 | lookup_minimal_symbol_by_pc_section (CORE_ADDR pc_in, struct obj_section *section, |
| 675 | lookup_msym_prefer prefer) |
| 676 | { |
| 677 | int lo; |
| 678 | int hi; |
| 679 | int newobj; |
| 680 | struct objfile *objfile; |
| 681 | struct minimal_symbol *msymbol; |
| 682 | struct minimal_symbol *best_symbol = NULL; |
| 683 | struct objfile *best_objfile = NULL; |
| 684 | struct bound_minimal_symbol result; |
| 685 | enum minimal_symbol_type want_type; |
| 686 | |
| 687 | if (section == NULL) |
| 688 | { |
| 689 | section = find_pc_section (pc_in); |
| 690 | if (section == NULL) |
| 691 | return {}; |
| 692 | } |
| 693 | |
| 694 | switch (prefer) |
| 695 | { |
| 696 | case lookup_msym_prefer::TEXT: |
| 697 | want_type = mst_text; |
| 698 | break; |
| 699 | case lookup_msym_prefer::TRAMPOLINE: |
| 700 | want_type = mst_solib_trampoline; |
| 701 | break; |
| 702 | case lookup_msym_prefer::GNU_IFUNC: |
| 703 | want_type = mst_text_gnu_ifunc; |
| 704 | break; |
| 705 | } |
| 706 | |
| 707 | /* We can not require the symbol found to be in section, because |
| 708 | e.g. IRIX 6.5 mdebug relies on this code returning an absolute |
| 709 | symbol - but find_pc_section won't return an absolute section and |
| 710 | hence the code below would skip over absolute symbols. We can |
| 711 | still take advantage of the call to find_pc_section, though - the |
| 712 | object file still must match. In case we have separate debug |
| 713 | files, search both the file and its separate debug file. There's |
| 714 | no telling which one will have the minimal symbols. */ |
| 715 | |
| 716 | gdb_assert (section != NULL); |
| 717 | |
| 718 | for (objfile = section->objfile; |
| 719 | objfile != NULL; |
| 720 | objfile = objfile_separate_debug_iterate (section->objfile, objfile)) |
| 721 | { |
| 722 | CORE_ADDR pc = pc_in; |
| 723 | |
| 724 | /* If this objfile has a minimal symbol table, go search it using |
| 725 | a binary search. Note that a minimal symbol table always consists |
| 726 | of at least two symbols, a "real" symbol and the terminating |
| 727 | "null symbol". If there are no real symbols, then there is no |
| 728 | minimal symbol table at all. */ |
| 729 | |
| 730 | if (objfile->per_bfd->minimal_symbol_count > 0) |
| 731 | { |
| 732 | int best_zero_sized = -1; |
| 733 | |
| 734 | msymbol = objfile->per_bfd->msymbols; |
| 735 | lo = 0; |
| 736 | hi = objfile->per_bfd->minimal_symbol_count - 1; |
| 737 | |
| 738 | /* This code assumes that the minimal symbols are sorted by |
| 739 | ascending address values. If the pc value is greater than or |
| 740 | equal to the first symbol's address, then some symbol in this |
| 741 | minimal symbol table is a suitable candidate for being the |
| 742 | "best" symbol. This includes the last real symbol, for cases |
| 743 | where the pc value is larger than any address in this vector. |
| 744 | |
| 745 | By iterating until the address associated with the current |
| 746 | hi index (the endpoint of the test interval) is less than |
| 747 | or equal to the desired pc value, we accomplish two things: |
| 748 | (1) the case where the pc value is larger than any minimal |
| 749 | symbol address is trivially solved, (2) the address associated |
| 750 | with the hi index is always the one we want when the interation |
| 751 | terminates. In essence, we are iterating the test interval |
| 752 | down until the pc value is pushed out of it from the high end. |
| 753 | |
| 754 | Warning: this code is trickier than it would appear at first. */ |
| 755 | |
| 756 | if (frob_address (objfile, &pc) |
| 757 | && pc >= MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[lo])) |
| 758 | { |
| 759 | while (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) > pc) |
| 760 | { |
| 761 | /* pc is still strictly less than highest address. */ |
| 762 | /* Note "new" will always be >= lo. */ |
| 763 | newobj = (lo + hi) / 2; |
| 764 | if ((MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[newobj]) >= pc) |
| 765 | || (lo == newobj)) |
| 766 | { |
| 767 | hi = newobj; |
| 768 | } |
| 769 | else |
| 770 | { |
| 771 | lo = newobj; |
| 772 | } |
| 773 | } |
| 774 | |
| 775 | /* If we have multiple symbols at the same address, we want |
| 776 | hi to point to the last one. That way we can find the |
| 777 | right symbol if it has an index greater than hi. */ |
| 778 | while (hi < objfile->per_bfd->minimal_symbol_count - 1 |
| 779 | && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) |
| 780 | == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi + 1]))) |
| 781 | hi++; |
| 782 | |
| 783 | /* Skip various undesirable symbols. */ |
| 784 | while (hi >= 0) |
| 785 | { |
| 786 | /* Skip any absolute symbols. This is apparently |
| 787 | what adb and dbx do, and is needed for the CM-5. |
| 788 | There are two known possible problems: (1) on |
| 789 | ELF, apparently end, edata, etc. are absolute. |
| 790 | Not sure ignoring them here is a big deal, but if |
| 791 | we want to use them, the fix would go in |
| 792 | elfread.c. (2) I think shared library entry |
| 793 | points on the NeXT are absolute. If we want |
| 794 | special handling for this it probably should be |
| 795 | triggered by a special mst_abs_or_lib or some |
| 796 | such. */ |
| 797 | |
| 798 | if (MSYMBOL_TYPE (&msymbol[hi]) == mst_abs) |
| 799 | { |
| 800 | hi--; |
| 801 | continue; |
| 802 | } |
| 803 | |
| 804 | /* If SECTION was specified, skip any symbol from |
| 805 | wrong section. */ |
| 806 | if (section |
| 807 | /* Some types of debug info, such as COFF, |
| 808 | don't fill the bfd_section member, so don't |
| 809 | throw away symbols on those platforms. */ |
| 810 | && MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]) != NULL |
| 811 | && (!matching_obj_sections |
| 812 | (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]), |
| 813 | section))) |
| 814 | { |
| 815 | hi--; |
| 816 | continue; |
| 817 | } |
| 818 | |
| 819 | /* If we are looking for a trampoline and this is a |
| 820 | text symbol, or the other way around, check the |
| 821 | preceding symbol too. If they are otherwise |
| 822 | identical prefer that one. */ |
| 823 | if (hi > 0 |
| 824 | && MSYMBOL_TYPE (&msymbol[hi]) != want_type |
| 825 | && MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type |
| 826 | && (MSYMBOL_SIZE (&msymbol[hi]) |
| 827 | == MSYMBOL_SIZE (&msymbol[hi - 1])) |
| 828 | && (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) |
| 829 | == MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1])) |
| 830 | && (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]) |
| 831 | == MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi - 1]))) |
| 832 | { |
| 833 | hi--; |
| 834 | continue; |
| 835 | } |
| 836 | |
| 837 | /* If the minimal symbol has a zero size, save it |
| 838 | but keep scanning backwards looking for one with |
| 839 | a non-zero size. A zero size may mean that the |
| 840 | symbol isn't an object or function (e.g. a |
| 841 | label), or it may just mean that the size was not |
| 842 | specified. */ |
| 843 | if (MSYMBOL_SIZE (&msymbol[hi]) == 0) |
| 844 | { |
| 845 | if (best_zero_sized == -1) |
| 846 | best_zero_sized = hi; |
| 847 | hi--; |
| 848 | continue; |
| 849 | } |
| 850 | |
| 851 | /* If we are past the end of the current symbol, try |
| 852 | the previous symbol if it has a larger overlapping |
| 853 | size. This happens on i686-pc-linux-gnu with glibc; |
| 854 | the nocancel variants of system calls are inside |
| 855 | the cancellable variants, but both have sizes. */ |
| 856 | if (hi > 0 |
| 857 | && MSYMBOL_SIZE (&msymbol[hi]) != 0 |
| 858 | && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) |
| 859 | + MSYMBOL_SIZE (&msymbol[hi])) |
| 860 | && pc < (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1]) |
| 861 | + MSYMBOL_SIZE (&msymbol[hi - 1]))) |
| 862 | { |
| 863 | hi--; |
| 864 | continue; |
| 865 | } |
| 866 | |
| 867 | /* Otherwise, this symbol must be as good as we're going |
| 868 | to get. */ |
| 869 | break; |
| 870 | } |
| 871 | |
| 872 | /* If HI has a zero size, and best_zero_sized is set, |
| 873 | then we had two or more zero-sized symbols; prefer |
| 874 | the first one we found (which may have a higher |
| 875 | address). Also, if we ran off the end, be sure |
| 876 | to back up. */ |
| 877 | if (best_zero_sized != -1 |
| 878 | && (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0)) |
| 879 | hi = best_zero_sized; |
| 880 | |
| 881 | /* If the minimal symbol has a non-zero size, and this |
| 882 | PC appears to be outside the symbol's contents, then |
| 883 | refuse to use this symbol. If we found a zero-sized |
| 884 | symbol with an address greater than this symbol's, |
| 885 | use that instead. We assume that if symbols have |
| 886 | specified sizes, they do not overlap. */ |
| 887 | |
| 888 | if (hi >= 0 |
| 889 | && MSYMBOL_SIZE (&msymbol[hi]) != 0 |
| 890 | && pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) |
| 891 | + MSYMBOL_SIZE (&msymbol[hi]))) |
| 892 | { |
| 893 | if (best_zero_sized != -1) |
| 894 | hi = best_zero_sized; |
| 895 | else |
| 896 | /* Go on to the next object file. */ |
| 897 | continue; |
| 898 | } |
| 899 | |
| 900 | /* The minimal symbol indexed by hi now is the best one in this |
| 901 | objfile's minimal symbol table. See if it is the best one |
| 902 | overall. */ |
| 903 | |
| 904 | if (hi >= 0 |
| 905 | && ((best_symbol == NULL) || |
| 906 | (MSYMBOL_VALUE_RAW_ADDRESS (best_symbol) < |
| 907 | MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])))) |
| 908 | { |
| 909 | best_symbol = &msymbol[hi]; |
| 910 | best_objfile = objfile; |
| 911 | } |
| 912 | } |
| 913 | } |
| 914 | } |
| 915 | |
| 916 | result.minsym = best_symbol; |
| 917 | result.objfile = best_objfile; |
| 918 | return result; |
| 919 | } |
| 920 | |
| 921 | /* See minsyms.h. */ |
| 922 | |
| 923 | struct bound_minimal_symbol |
| 924 | lookup_minimal_symbol_by_pc (CORE_ADDR pc) |
| 925 | { |
| 926 | return lookup_minimal_symbol_by_pc_section (pc, NULL); |
| 927 | } |
| 928 | |
| 929 | /* Return non-zero iff PC is in an STT_GNU_IFUNC function resolver. */ |
| 930 | |
| 931 | int |
| 932 | in_gnu_ifunc_stub (CORE_ADDR pc) |
| 933 | { |
| 934 | bound_minimal_symbol msymbol |
| 935 | = lookup_minimal_symbol_by_pc_section (pc, NULL, |
| 936 | lookup_msym_prefer::GNU_IFUNC); |
| 937 | return msymbol.minsym && MSYMBOL_TYPE (msymbol.minsym) == mst_text_gnu_ifunc; |
| 938 | } |
| 939 | |
| 940 | /* See elf_gnu_ifunc_resolve_addr for its real implementation. */ |
| 941 | |
| 942 | static CORE_ADDR |
| 943 | stub_gnu_ifunc_resolve_addr (struct gdbarch *gdbarch, CORE_ADDR pc) |
| 944 | { |
| 945 | error (_("GDB cannot resolve STT_GNU_IFUNC symbol at address %s without " |
| 946 | "the ELF support compiled in."), |
| 947 | paddress (gdbarch, pc)); |
| 948 | } |
| 949 | |
| 950 | /* See elf_gnu_ifunc_resolve_name for its real implementation. */ |
| 951 | |
| 952 | static int |
| 953 | stub_gnu_ifunc_resolve_name (const char *function_name, |
| 954 | CORE_ADDR *function_address_p) |
| 955 | { |
| 956 | error (_("GDB cannot resolve STT_GNU_IFUNC symbol \"%s\" without " |
| 957 | "the ELF support compiled in."), |
| 958 | function_name); |
| 959 | } |
| 960 | |
| 961 | /* See elf_gnu_ifunc_resolver_stop for its real implementation. */ |
| 962 | |
| 963 | static void |
| 964 | stub_gnu_ifunc_resolver_stop (struct breakpoint *b) |
| 965 | { |
| 966 | internal_error (__FILE__, __LINE__, |
| 967 | _("elf_gnu_ifunc_resolver_stop cannot be reached.")); |
| 968 | } |
| 969 | |
| 970 | /* See elf_gnu_ifunc_resolver_return_stop for its real implementation. */ |
| 971 | |
| 972 | static void |
| 973 | stub_gnu_ifunc_resolver_return_stop (struct breakpoint *b) |
| 974 | { |
| 975 | internal_error (__FILE__, __LINE__, |
| 976 | _("elf_gnu_ifunc_resolver_return_stop cannot be reached.")); |
| 977 | } |
| 978 | |
| 979 | /* See elf_gnu_ifunc_fns for its real implementation. */ |
| 980 | |
| 981 | static const struct gnu_ifunc_fns stub_gnu_ifunc_fns = |
| 982 | { |
| 983 | stub_gnu_ifunc_resolve_addr, |
| 984 | stub_gnu_ifunc_resolve_name, |
| 985 | stub_gnu_ifunc_resolver_stop, |
| 986 | stub_gnu_ifunc_resolver_return_stop, |
| 987 | }; |
| 988 | |
| 989 | /* A placeholder for &elf_gnu_ifunc_fns. */ |
| 990 | |
| 991 | const struct gnu_ifunc_fns *gnu_ifunc_fns_p = &stub_gnu_ifunc_fns; |
| 992 | |
| 993 | \f |
| 994 | |
| 995 | /* Return leading symbol character for a BFD. If BFD is NULL, |
| 996 | return the leading symbol character from the main objfile. */ |
| 997 | |
| 998 | static int |
| 999 | get_symbol_leading_char (bfd *abfd) |
| 1000 | { |
| 1001 | if (abfd != NULL) |
| 1002 | return bfd_get_symbol_leading_char (abfd); |
| 1003 | if (symfile_objfile != NULL && symfile_objfile->obfd != NULL) |
| 1004 | return bfd_get_symbol_leading_char (symfile_objfile->obfd); |
| 1005 | return 0; |
| 1006 | } |
| 1007 | |
| 1008 | /* See minsyms.h. */ |
| 1009 | |
| 1010 | minimal_symbol_reader::minimal_symbol_reader (struct objfile *obj) |
| 1011 | : m_objfile (obj), |
| 1012 | m_msym_bunch (NULL), |
| 1013 | /* Note that presetting m_msym_bunch_index to BUNCH_SIZE causes the |
| 1014 | first call to save a minimal symbol to allocate the memory for |
| 1015 | the first bunch. */ |
| 1016 | m_msym_bunch_index (BUNCH_SIZE), |
| 1017 | m_msym_count (0) |
| 1018 | { |
| 1019 | } |
| 1020 | |
| 1021 | /* Discard the currently collected minimal symbols, if any. If we wish |
| 1022 | to save them for later use, we must have already copied them somewhere |
| 1023 | else before calling this function. |
| 1024 | |
| 1025 | FIXME: We could allocate the minimal symbol bunches on their own |
| 1026 | obstack and then simply blow the obstack away when we are done with |
| 1027 | it. Is it worth the extra trouble though? */ |
| 1028 | |
| 1029 | minimal_symbol_reader::~minimal_symbol_reader () |
| 1030 | { |
| 1031 | struct msym_bunch *next; |
| 1032 | |
| 1033 | while (m_msym_bunch != NULL) |
| 1034 | { |
| 1035 | next = m_msym_bunch->next; |
| 1036 | xfree (m_msym_bunch); |
| 1037 | m_msym_bunch = next; |
| 1038 | } |
| 1039 | } |
| 1040 | |
| 1041 | /* See minsyms.h. */ |
| 1042 | |
| 1043 | void |
| 1044 | minimal_symbol_reader::record (const char *name, CORE_ADDR address, |
| 1045 | enum minimal_symbol_type ms_type) |
| 1046 | { |
| 1047 | int section; |
| 1048 | |
| 1049 | switch (ms_type) |
| 1050 | { |
| 1051 | case mst_text: |
| 1052 | case mst_text_gnu_ifunc: |
| 1053 | case mst_file_text: |
| 1054 | case mst_solib_trampoline: |
| 1055 | section = SECT_OFF_TEXT (m_objfile); |
| 1056 | break; |
| 1057 | case mst_data: |
| 1058 | case mst_data_gnu_ifunc: |
| 1059 | case mst_file_data: |
| 1060 | section = SECT_OFF_DATA (m_objfile); |
| 1061 | break; |
| 1062 | case mst_bss: |
| 1063 | case mst_file_bss: |
| 1064 | section = SECT_OFF_BSS (m_objfile); |
| 1065 | break; |
| 1066 | default: |
| 1067 | section = -1; |
| 1068 | } |
| 1069 | |
| 1070 | record_with_info (name, address, ms_type, section); |
| 1071 | } |
| 1072 | |
| 1073 | /* See minsyms.h. */ |
| 1074 | |
| 1075 | struct minimal_symbol * |
| 1076 | minimal_symbol_reader::record_full (const char *name, int name_len, |
| 1077 | bool copy_name, CORE_ADDR address, |
| 1078 | enum minimal_symbol_type ms_type, |
| 1079 | int section) |
| 1080 | { |
| 1081 | struct msym_bunch *newobj; |
| 1082 | struct minimal_symbol *msymbol; |
| 1083 | |
| 1084 | /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into |
| 1085 | the minimal symbols, because if there is also another symbol |
| 1086 | at the same address (e.g. the first function of the file), |
| 1087 | lookup_minimal_symbol_by_pc would have no way of getting the |
| 1088 | right one. */ |
| 1089 | if (ms_type == mst_file_text && name[0] == 'g' |
| 1090 | && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0 |
| 1091 | || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0)) |
| 1092 | return (NULL); |
| 1093 | |
| 1094 | /* It's safe to strip the leading char here once, since the name |
| 1095 | is also stored stripped in the minimal symbol table. */ |
| 1096 | if (name[0] == get_symbol_leading_char (m_objfile->obfd)) |
| 1097 | { |
| 1098 | ++name; |
| 1099 | --name_len; |
| 1100 | } |
| 1101 | |
| 1102 | if (ms_type == mst_file_text && startswith (name, "__gnu_compiled")) |
| 1103 | return (NULL); |
| 1104 | |
| 1105 | if (m_msym_bunch_index == BUNCH_SIZE) |
| 1106 | { |
| 1107 | newobj = XCNEW (struct msym_bunch); |
| 1108 | m_msym_bunch_index = 0; |
| 1109 | newobj->next = m_msym_bunch; |
| 1110 | m_msym_bunch = newobj; |
| 1111 | } |
| 1112 | msymbol = &m_msym_bunch->contents[m_msym_bunch_index]; |
| 1113 | MSYMBOL_SET_LANGUAGE (msymbol, language_auto, |
| 1114 | &m_objfile->per_bfd->storage_obstack); |
| 1115 | MSYMBOL_SET_NAMES (msymbol, name, name_len, copy_name, m_objfile); |
| 1116 | |
| 1117 | SET_MSYMBOL_VALUE_ADDRESS (msymbol, address); |
| 1118 | MSYMBOL_SECTION (msymbol) = section; |
| 1119 | |
| 1120 | MSYMBOL_TYPE (msymbol) = ms_type; |
| 1121 | MSYMBOL_TARGET_FLAG_1 (msymbol) = 0; |
| 1122 | MSYMBOL_TARGET_FLAG_2 (msymbol) = 0; |
| 1123 | /* Do not use the SET_MSYMBOL_SIZE macro to initialize the size, |
| 1124 | as it would also set the has_size flag. */ |
| 1125 | msymbol->size = 0; |
| 1126 | |
| 1127 | /* The hash pointers must be cleared! If they're not, |
| 1128 | add_minsym_to_hash_table will NOT add this msymbol to the hash table. */ |
| 1129 | msymbol->hash_next = NULL; |
| 1130 | msymbol->demangled_hash_next = NULL; |
| 1131 | |
| 1132 | /* If we already read minimal symbols for this objfile, then don't |
| 1133 | ever allocate a new one. */ |
| 1134 | if (!m_objfile->per_bfd->minsyms_read) |
| 1135 | { |
| 1136 | m_msym_bunch_index++; |
| 1137 | m_objfile->per_bfd->n_minsyms++; |
| 1138 | } |
| 1139 | m_msym_count++; |
| 1140 | return msymbol; |
| 1141 | } |
| 1142 | |
| 1143 | /* Compare two minimal symbols by address and return a signed result based |
| 1144 | on unsigned comparisons, so that we sort into unsigned numeric order. |
| 1145 | Within groups with the same address, sort by name. */ |
| 1146 | |
| 1147 | static int |
| 1148 | compare_minimal_symbols (const void *fn1p, const void *fn2p) |
| 1149 | { |
| 1150 | const struct minimal_symbol *fn1; |
| 1151 | const struct minimal_symbol *fn2; |
| 1152 | |
| 1153 | fn1 = (const struct minimal_symbol *) fn1p; |
| 1154 | fn2 = (const struct minimal_symbol *) fn2p; |
| 1155 | |
| 1156 | if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) < MSYMBOL_VALUE_RAW_ADDRESS (fn2)) |
| 1157 | { |
| 1158 | return (-1); /* addr 1 is less than addr 2. */ |
| 1159 | } |
| 1160 | else if (MSYMBOL_VALUE_RAW_ADDRESS (fn1) > MSYMBOL_VALUE_RAW_ADDRESS (fn2)) |
| 1161 | { |
| 1162 | return (1); /* addr 1 is greater than addr 2. */ |
| 1163 | } |
| 1164 | else |
| 1165 | /* addrs are equal: sort by name */ |
| 1166 | { |
| 1167 | const char *name1 = MSYMBOL_LINKAGE_NAME (fn1); |
| 1168 | const char *name2 = MSYMBOL_LINKAGE_NAME (fn2); |
| 1169 | |
| 1170 | if (name1 && name2) /* both have names */ |
| 1171 | return strcmp (name1, name2); |
| 1172 | else if (name2) |
| 1173 | return 1; /* fn1 has no name, so it is "less". */ |
| 1174 | else if (name1) /* fn2 has no name, so it is "less". */ |
| 1175 | return -1; |
| 1176 | else |
| 1177 | return (0); /* Neither has a name, so they're equal. */ |
| 1178 | } |
| 1179 | } |
| 1180 | |
| 1181 | /* Compact duplicate entries out of a minimal symbol table by walking |
| 1182 | through the table and compacting out entries with duplicate addresses |
| 1183 | and matching names. Return the number of entries remaining. |
| 1184 | |
| 1185 | On entry, the table resides between msymbol[0] and msymbol[mcount]. |
| 1186 | On exit, it resides between msymbol[0] and msymbol[result_count]. |
| 1187 | |
| 1188 | When files contain multiple sources of symbol information, it is |
| 1189 | possible for the minimal symbol table to contain many duplicate entries. |
| 1190 | As an example, SVR4 systems use ELF formatted object files, which |
| 1191 | usually contain at least two different types of symbol tables (a |
| 1192 | standard ELF one and a smaller dynamic linking table), as well as |
| 1193 | DWARF debugging information for files compiled with -g. |
| 1194 | |
| 1195 | Without compacting, the minimal symbol table for gdb itself contains |
| 1196 | over a 1000 duplicates, about a third of the total table size. Aside |
| 1197 | from the potential trap of not noticing that two successive entries |
| 1198 | identify the same location, this duplication impacts the time required |
| 1199 | to linearly scan the table, which is done in a number of places. So we |
| 1200 | just do one linear scan here and toss out the duplicates. |
| 1201 | |
| 1202 | Note that we are not concerned here about recovering the space that |
| 1203 | is potentially freed up, because the strings themselves are allocated |
| 1204 | on the storage_obstack, and will get automatically freed when the symbol |
| 1205 | table is freed. The caller can free up the unused minimal symbols at |
| 1206 | the end of the compacted region if their allocation strategy allows it. |
| 1207 | |
| 1208 | Also note we only go up to the next to last entry within the loop |
| 1209 | and then copy the last entry explicitly after the loop terminates. |
| 1210 | |
| 1211 | Since the different sources of information for each symbol may |
| 1212 | have different levels of "completeness", we may have duplicates |
| 1213 | that have one entry with type "mst_unknown" and the other with a |
| 1214 | known type. So if the one we are leaving alone has type mst_unknown, |
| 1215 | overwrite its type with the type from the one we are compacting out. */ |
| 1216 | |
| 1217 | static int |
| 1218 | compact_minimal_symbols (struct minimal_symbol *msymbol, int mcount, |
| 1219 | struct objfile *objfile) |
| 1220 | { |
| 1221 | struct minimal_symbol *copyfrom; |
| 1222 | struct minimal_symbol *copyto; |
| 1223 | |
| 1224 | if (mcount > 0) |
| 1225 | { |
| 1226 | copyfrom = copyto = msymbol; |
| 1227 | while (copyfrom < msymbol + mcount - 1) |
| 1228 | { |
| 1229 | if (MSYMBOL_VALUE_RAW_ADDRESS (copyfrom) |
| 1230 | == MSYMBOL_VALUE_RAW_ADDRESS ((copyfrom + 1)) |
| 1231 | && MSYMBOL_SECTION (copyfrom) == MSYMBOL_SECTION (copyfrom + 1) |
| 1232 | && strcmp (MSYMBOL_LINKAGE_NAME (copyfrom), |
| 1233 | MSYMBOL_LINKAGE_NAME ((copyfrom + 1))) == 0) |
| 1234 | { |
| 1235 | if (MSYMBOL_TYPE ((copyfrom + 1)) == mst_unknown) |
| 1236 | { |
| 1237 | MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom); |
| 1238 | } |
| 1239 | copyfrom++; |
| 1240 | } |
| 1241 | else |
| 1242 | *copyto++ = *copyfrom++; |
| 1243 | } |
| 1244 | *copyto++ = *copyfrom++; |
| 1245 | mcount = copyto - msymbol; |
| 1246 | } |
| 1247 | return (mcount); |
| 1248 | } |
| 1249 | |
| 1250 | /* Build (or rebuild) the minimal symbol hash tables. This is necessary |
| 1251 | after compacting or sorting the table since the entries move around |
| 1252 | thus causing the internal minimal_symbol pointers to become jumbled. */ |
| 1253 | |
| 1254 | static void |
| 1255 | build_minimal_symbol_hash_tables (struct objfile *objfile) |
| 1256 | { |
| 1257 | int i; |
| 1258 | struct minimal_symbol *msym; |
| 1259 | |
| 1260 | /* Clear the hash tables. */ |
| 1261 | for (i = 0; i < MINIMAL_SYMBOL_HASH_SIZE; i++) |
| 1262 | { |
| 1263 | objfile->per_bfd->msymbol_hash[i] = 0; |
| 1264 | objfile->per_bfd->msymbol_demangled_hash[i] = 0; |
| 1265 | } |
| 1266 | |
| 1267 | /* Now, (re)insert the actual entries. */ |
| 1268 | for ((i = objfile->per_bfd->minimal_symbol_count, |
| 1269 | msym = objfile->per_bfd->msymbols); |
| 1270 | i > 0; |
| 1271 | i--, msym++) |
| 1272 | { |
| 1273 | msym->hash_next = 0; |
| 1274 | add_minsym_to_hash_table (msym, objfile->per_bfd->msymbol_hash); |
| 1275 | |
| 1276 | msym->demangled_hash_next = 0; |
| 1277 | if (MSYMBOL_SEARCH_NAME (msym) != MSYMBOL_LINKAGE_NAME (msym)) |
| 1278 | add_minsym_to_demangled_hash_table (msym, objfile); |
| 1279 | } |
| 1280 | } |
| 1281 | |
| 1282 | /* Add the minimal symbols in the existing bunches to the objfile's official |
| 1283 | minimal symbol table. In most cases there is no minimal symbol table yet |
| 1284 | for this objfile, and the existing bunches are used to create one. Once |
| 1285 | in a while (for shared libraries for example), we add symbols (e.g. common |
| 1286 | symbols) to an existing objfile. |
| 1287 | |
| 1288 | Because of the way minimal symbols are collected, we generally have no way |
| 1289 | of knowing what source language applies to any particular minimal symbol. |
| 1290 | Specifically, we have no way of knowing if the minimal symbol comes from a |
| 1291 | C++ compilation unit or not. So for the sake of supporting cached |
| 1292 | demangled C++ names, we have no choice but to try and demangle each new one |
| 1293 | that comes in. If the demangling succeeds, then we assume it is a C++ |
| 1294 | symbol and set the symbol's language and demangled name fields |
| 1295 | appropriately. Note that in order to avoid unnecessary demanglings, and |
| 1296 | allocating obstack space that subsequently can't be freed for the demangled |
| 1297 | names, we mark all newly added symbols with language_auto. After |
| 1298 | compaction of the minimal symbols, we go back and scan the entire minimal |
| 1299 | symbol table looking for these new symbols. For each new symbol we attempt |
| 1300 | to demangle it, and if successful, record it as a language_cplus symbol |
| 1301 | and cache the demangled form on the symbol obstack. Symbols which don't |
| 1302 | demangle are marked as language_unknown symbols, which inhibits future |
| 1303 | attempts to demangle them if we later add more minimal symbols. */ |
| 1304 | |
| 1305 | void |
| 1306 | minimal_symbol_reader::install () |
| 1307 | { |
| 1308 | int bindex; |
| 1309 | int mcount; |
| 1310 | struct msym_bunch *bunch; |
| 1311 | struct minimal_symbol *msymbols; |
| 1312 | int alloc_count; |
| 1313 | |
| 1314 | if (m_objfile->per_bfd->minsyms_read) |
| 1315 | return; |
| 1316 | |
| 1317 | if (m_msym_count > 0) |
| 1318 | { |
| 1319 | if (symtab_create_debug) |
| 1320 | { |
| 1321 | fprintf_unfiltered (gdb_stdlog, |
| 1322 | "Installing %d minimal symbols of objfile %s.\n", |
| 1323 | m_msym_count, objfile_name (m_objfile)); |
| 1324 | } |
| 1325 | |
| 1326 | /* Allocate enough space in the obstack, into which we will gather the |
| 1327 | bunches of new and existing minimal symbols, sort them, and then |
| 1328 | compact out the duplicate entries. Once we have a final table, |
| 1329 | we will give back the excess space. */ |
| 1330 | |
| 1331 | alloc_count = m_msym_count + m_objfile->per_bfd->minimal_symbol_count + 1; |
| 1332 | obstack_blank (&m_objfile->per_bfd->storage_obstack, |
| 1333 | alloc_count * sizeof (struct minimal_symbol)); |
| 1334 | msymbols = (struct minimal_symbol *) |
| 1335 | obstack_base (&m_objfile->per_bfd->storage_obstack); |
| 1336 | |
| 1337 | /* Copy in the existing minimal symbols, if there are any. */ |
| 1338 | |
| 1339 | if (m_objfile->per_bfd->minimal_symbol_count) |
| 1340 | memcpy ((char *) msymbols, (char *) m_objfile->per_bfd->msymbols, |
| 1341 | m_objfile->per_bfd->minimal_symbol_count * sizeof (struct minimal_symbol)); |
| 1342 | |
| 1343 | /* Walk through the list of minimal symbol bunches, adding each symbol |
| 1344 | to the new contiguous array of symbols. Note that we start with the |
| 1345 | current, possibly partially filled bunch (thus we use the current |
| 1346 | msym_bunch_index for the first bunch we copy over), and thereafter |
| 1347 | each bunch is full. */ |
| 1348 | |
| 1349 | mcount = m_objfile->per_bfd->minimal_symbol_count; |
| 1350 | |
| 1351 | for (bunch = m_msym_bunch; bunch != NULL; bunch = bunch->next) |
| 1352 | { |
| 1353 | for (bindex = 0; bindex < m_msym_bunch_index; bindex++, mcount++) |
| 1354 | msymbols[mcount] = bunch->contents[bindex]; |
| 1355 | m_msym_bunch_index = BUNCH_SIZE; |
| 1356 | } |
| 1357 | |
| 1358 | /* Sort the minimal symbols by address. */ |
| 1359 | |
| 1360 | qsort (msymbols, mcount, sizeof (struct minimal_symbol), |
| 1361 | compare_minimal_symbols); |
| 1362 | |
| 1363 | /* Compact out any duplicates, and free up whatever space we are |
| 1364 | no longer using. */ |
| 1365 | |
| 1366 | mcount = compact_minimal_symbols (msymbols, mcount, m_objfile); |
| 1367 | |
| 1368 | obstack_blank_fast (&m_objfile->per_bfd->storage_obstack, |
| 1369 | (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol)); |
| 1370 | msymbols = (struct minimal_symbol *) |
| 1371 | obstack_finish (&m_objfile->per_bfd->storage_obstack); |
| 1372 | |
| 1373 | /* We also terminate the minimal symbol table with a "null symbol", |
| 1374 | which is *not* included in the size of the table. This makes it |
| 1375 | easier to find the end of the table when we are handed a pointer |
| 1376 | to some symbol in the middle of it. Zero out the fields in the |
| 1377 | "null symbol" allocated at the end of the array. Note that the |
| 1378 | symbol count does *not* include this null symbol, which is why it |
| 1379 | is indexed by mcount and not mcount-1. */ |
| 1380 | |
| 1381 | memset (&msymbols[mcount], 0, sizeof (struct minimal_symbol)); |
| 1382 | |
| 1383 | /* Attach the minimal symbol table to the specified objfile. |
| 1384 | The strings themselves are also located in the storage_obstack |
| 1385 | of this objfile. */ |
| 1386 | |
| 1387 | m_objfile->per_bfd->minimal_symbol_count = mcount; |
| 1388 | m_objfile->per_bfd->msymbols = msymbols; |
| 1389 | |
| 1390 | /* Now build the hash tables; we can't do this incrementally |
| 1391 | at an earlier point since we weren't finished with the obstack |
| 1392 | yet. (And if the msymbol obstack gets moved, all the internal |
| 1393 | pointers to other msymbols need to be adjusted.) */ |
| 1394 | build_minimal_symbol_hash_tables (m_objfile); |
| 1395 | } |
| 1396 | } |
| 1397 | |
| 1398 | /* See minsyms.h. */ |
| 1399 | |
| 1400 | void |
| 1401 | terminate_minimal_symbol_table (struct objfile *objfile) |
| 1402 | { |
| 1403 | if (! objfile->per_bfd->msymbols) |
| 1404 | objfile->per_bfd->msymbols = XOBNEW (&objfile->per_bfd->storage_obstack, |
| 1405 | minimal_symbol); |
| 1406 | |
| 1407 | { |
| 1408 | struct minimal_symbol *m |
| 1409 | = &objfile->per_bfd->msymbols[objfile->per_bfd->minimal_symbol_count]; |
| 1410 | |
| 1411 | memset (m, 0, sizeof (*m)); |
| 1412 | /* Don't rely on these enumeration values being 0's. */ |
| 1413 | MSYMBOL_TYPE (m) = mst_unknown; |
| 1414 | MSYMBOL_SET_LANGUAGE (m, language_unknown, |
| 1415 | &objfile->per_bfd->storage_obstack); |
| 1416 | } |
| 1417 | } |
| 1418 | |
| 1419 | /* Check if PC is in a shared library trampoline code stub. |
| 1420 | Return minimal symbol for the trampoline entry or NULL if PC is not |
| 1421 | in a trampoline code stub. */ |
| 1422 | |
| 1423 | static struct minimal_symbol * |
| 1424 | lookup_solib_trampoline_symbol_by_pc (CORE_ADDR pc) |
| 1425 | { |
| 1426 | bound_minimal_symbol msymbol |
| 1427 | = lookup_minimal_symbol_by_pc_section (pc, NULL, |
| 1428 | lookup_msym_prefer::TRAMPOLINE); |
| 1429 | |
| 1430 | if (msymbol.minsym != NULL |
| 1431 | && MSYMBOL_TYPE (msymbol.minsym) == mst_solib_trampoline) |
| 1432 | return msymbol.minsym; |
| 1433 | return NULL; |
| 1434 | } |
| 1435 | |
| 1436 | /* If PC is in a shared library trampoline code stub, return the |
| 1437 | address of the `real' function belonging to the stub. |
| 1438 | Return 0 if PC is not in a trampoline code stub or if the real |
| 1439 | function is not found in the minimal symbol table. |
| 1440 | |
| 1441 | We may fail to find the right function if a function with the |
| 1442 | same name is defined in more than one shared library, but this |
| 1443 | is considered bad programming style. We could return 0 if we find |
| 1444 | a duplicate function in case this matters someday. */ |
| 1445 | |
| 1446 | CORE_ADDR |
| 1447 | find_solib_trampoline_target (struct frame_info *frame, CORE_ADDR pc) |
| 1448 | { |
| 1449 | struct objfile *objfile; |
| 1450 | struct minimal_symbol *msymbol; |
| 1451 | struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc); |
| 1452 | |
| 1453 | if (tsymbol != NULL) |
| 1454 | { |
| 1455 | ALL_MSYMBOLS (objfile, msymbol) |
| 1456 | { |
| 1457 | /* Also handle minimal symbols pointing to function descriptors. */ |
| 1458 | if ((MSYMBOL_TYPE (msymbol) == mst_text |
| 1459 | || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc |
| 1460 | || MSYMBOL_TYPE (msymbol) == mst_data |
| 1461 | || MSYMBOL_TYPE (msymbol) == mst_data_gnu_ifunc) |
| 1462 | && strcmp (MSYMBOL_LINKAGE_NAME (msymbol), |
| 1463 | MSYMBOL_LINKAGE_NAME (tsymbol)) == 0) |
| 1464 | { |
| 1465 | CORE_ADDR func; |
| 1466 | |
| 1467 | /* Ignore data symbols that are not function |
| 1468 | descriptors. */ |
| 1469 | if (msymbol_is_function (objfile, msymbol, &func)) |
| 1470 | return func; |
| 1471 | } |
| 1472 | } |
| 1473 | } |
| 1474 | return 0; |
| 1475 | } |
| 1476 | |
| 1477 | /* See minsyms.h. */ |
| 1478 | |
| 1479 | CORE_ADDR |
| 1480 | minimal_symbol_upper_bound (struct bound_minimal_symbol minsym) |
| 1481 | { |
| 1482 | int i; |
| 1483 | short section; |
| 1484 | struct obj_section *obj_section; |
| 1485 | CORE_ADDR result; |
| 1486 | struct minimal_symbol *msymbol; |
| 1487 | |
| 1488 | gdb_assert (minsym.minsym != NULL); |
| 1489 | |
| 1490 | /* If the minimal symbol has a size, use it. Otherwise use the |
| 1491 | lesser of the next minimal symbol in the same section, or the end |
| 1492 | of the section, as the end of the function. */ |
| 1493 | |
| 1494 | if (MSYMBOL_SIZE (minsym.minsym) != 0) |
| 1495 | return BMSYMBOL_VALUE_ADDRESS (minsym) + MSYMBOL_SIZE (minsym.minsym); |
| 1496 | |
| 1497 | /* Step over other symbols at this same address, and symbols in |
| 1498 | other sections, to find the next symbol in this section with a |
| 1499 | different address. */ |
| 1500 | |
| 1501 | msymbol = minsym.minsym; |
| 1502 | section = MSYMBOL_SECTION (msymbol); |
| 1503 | for (i = 1; MSYMBOL_LINKAGE_NAME (msymbol + i) != NULL; i++) |
| 1504 | { |
| 1505 | if ((MSYMBOL_VALUE_RAW_ADDRESS (msymbol + i) |
| 1506 | != MSYMBOL_VALUE_RAW_ADDRESS (msymbol)) |
| 1507 | && MSYMBOL_SECTION (msymbol + i) == section) |
| 1508 | break; |
| 1509 | } |
| 1510 | |
| 1511 | obj_section = MSYMBOL_OBJ_SECTION (minsym.objfile, minsym.minsym); |
| 1512 | if (MSYMBOL_LINKAGE_NAME (msymbol + i) != NULL |
| 1513 | && (MSYMBOL_VALUE_ADDRESS (minsym.objfile, msymbol + i) |
| 1514 | < obj_section_endaddr (obj_section))) |
| 1515 | result = MSYMBOL_VALUE_ADDRESS (minsym.objfile, msymbol + i); |
| 1516 | else |
| 1517 | /* We got the start address from the last msymbol in the objfile. |
| 1518 | So the end address is the end of the section. */ |
| 1519 | result = obj_section_endaddr (obj_section); |
| 1520 | |
| 1521 | return result; |
| 1522 | } |