| 1 | /* GDB routines for manipulating the minimal symbol tables. |
| 2 | Copyright 1992, 1993, 1994, 1995 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 2 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, write to the Free Software |
| 19 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ |
| 20 | |
| 21 | |
| 22 | /* This file contains support routines for creating, manipulating, and |
| 23 | destroying minimal symbol tables. |
| 24 | |
| 25 | Minimal symbol tables are used to hold some very basic information about |
| 26 | all defined global symbols (text, data, bss, abs, etc). The only two |
| 27 | required pieces of information are the symbol's name and the address |
| 28 | associated with that symbol. |
| 29 | |
| 30 | In many cases, even if a file was compiled with no special options for |
| 31 | debugging at all, as long as was not stripped it will contain sufficient |
| 32 | information to build useful minimal symbol tables using this structure. |
| 33 | |
| 34 | Even when a file contains enough debugging information to build a full |
| 35 | symbol table, these minimal symbols are still useful for quickly mapping |
| 36 | between names and addresses, and vice versa. They are also sometimes used |
| 37 | to figure out what full symbol table entries need to be read in. */ |
| 38 | |
| 39 | |
| 40 | #include "defs.h" |
| 41 | #include <string.h> |
| 42 | #include "symtab.h" |
| 43 | #include "bfd.h" |
| 44 | #include "symfile.h" |
| 45 | #include "objfiles.h" |
| 46 | #include "demangle.h" |
| 47 | #include "gdb-stabs.h" |
| 48 | |
| 49 | /* Accumulate the minimal symbols for each objfile in bunches of BUNCH_SIZE. |
| 50 | At the end, copy them all into one newly allocated location on an objfile's |
| 51 | symbol obstack. */ |
| 52 | |
| 53 | #define BUNCH_SIZE 127 |
| 54 | |
| 55 | struct msym_bunch |
| 56 | { |
| 57 | struct msym_bunch *next; |
| 58 | struct minimal_symbol contents[BUNCH_SIZE]; |
| 59 | }; |
| 60 | |
| 61 | /* Bunch currently being filled up. |
| 62 | The next field points to chain of filled bunches. */ |
| 63 | |
| 64 | static struct msym_bunch *msym_bunch; |
| 65 | |
| 66 | /* Number of slots filled in current bunch. */ |
| 67 | |
| 68 | static int msym_bunch_index; |
| 69 | |
| 70 | /* Total number of minimal symbols recorded so far for the objfile. */ |
| 71 | |
| 72 | static int msym_count; |
| 73 | |
| 74 | /* Prototypes for local functions. */ |
| 75 | |
| 76 | static int |
| 77 | compare_minimal_symbols PARAMS ((const void *, const void *)); |
| 78 | |
| 79 | static int |
| 80 | compact_minimal_symbols PARAMS ((struct minimal_symbol *, int)); |
| 81 | |
| 82 | /* Look through all the current minimal symbol tables and find the |
| 83 | first minimal symbol that matches NAME. If OBJF is non-NULL, limit |
| 84 | the search to that objfile. If SFILE is non-NULL, limit the search |
| 85 | to that source file. Returns a pointer to the minimal symbol that |
| 86 | matches, or NULL if no match is found. |
| 87 | |
| 88 | Note: One instance where there may be duplicate minimal symbols with |
| 89 | the same name is when the symbol tables for a shared library and the |
| 90 | symbol tables for an executable contain global symbols with the same |
| 91 | names (the dynamic linker deals with the duplication). */ |
| 92 | |
| 93 | struct minimal_symbol * |
| 94 | lookup_minimal_symbol (name, sfile, objf) |
| 95 | register const char *name; |
| 96 | const char *sfile; |
| 97 | struct objfile *objf; |
| 98 | { |
| 99 | struct objfile *objfile; |
| 100 | struct minimal_symbol *msymbol; |
| 101 | struct minimal_symbol *found_symbol = NULL; |
| 102 | struct minimal_symbol *found_file_symbol = NULL; |
| 103 | struct minimal_symbol *trampoline_symbol = NULL; |
| 104 | |
| 105 | #ifdef SOFUN_ADDRESS_MAYBE_MISSING |
| 106 | if (sfile != NULL) |
| 107 | { |
| 108 | char *p = strrchr (sfile, '/'); |
| 109 | if (p != NULL) |
| 110 | sfile = p + 1; |
| 111 | } |
| 112 | #endif |
| 113 | |
| 114 | for (objfile = object_files; |
| 115 | objfile != NULL && found_symbol == NULL; |
| 116 | objfile = objfile -> next) |
| 117 | { |
| 118 | if (objf == NULL || objf == objfile) |
| 119 | { |
| 120 | for (msymbol = objfile -> msymbols; |
| 121 | msymbol != NULL && SYMBOL_NAME (msymbol) != NULL && |
| 122 | found_symbol == NULL; |
| 123 | msymbol++) |
| 124 | { |
| 125 | if (SYMBOL_MATCHES_NAME (msymbol, name)) |
| 126 | { |
| 127 | switch (MSYMBOL_TYPE (msymbol)) |
| 128 | { |
| 129 | case mst_file_text: |
| 130 | case mst_file_data: |
| 131 | case mst_file_bss: |
| 132 | #ifdef SOFUN_ADDRESS_MAYBE_MISSING |
| 133 | if (sfile == NULL || STREQ (msymbol->filename, sfile)) |
| 134 | found_file_symbol = msymbol; |
| 135 | #else |
| 136 | /* We have neither the ability nor the need to |
| 137 | deal with the SFILE parameter. If we find |
| 138 | more than one symbol, just return the latest |
| 139 | one (the user can't expect useful behavior in |
| 140 | that case). */ |
| 141 | found_file_symbol = msymbol; |
| 142 | #endif |
| 143 | break; |
| 144 | |
| 145 | case mst_solib_trampoline: |
| 146 | |
| 147 | /* If a trampoline symbol is found, we prefer to |
| 148 | keep looking for the *real* symbol. If the |
| 149 | actual symbol is not found, then we'll use the |
| 150 | trampoline entry. */ |
| 151 | if (trampoline_symbol == NULL) |
| 152 | trampoline_symbol = msymbol; |
| 153 | break; |
| 154 | |
| 155 | case mst_unknown: |
| 156 | default: |
| 157 | found_symbol = msymbol; |
| 158 | break; |
| 159 | } |
| 160 | } |
| 161 | } |
| 162 | } |
| 163 | } |
| 164 | /* External symbols are best. */ |
| 165 | if (found_symbol) |
| 166 | return found_symbol; |
| 167 | |
| 168 | /* File-local symbols are next best. */ |
| 169 | if (found_file_symbol) |
| 170 | return found_file_symbol; |
| 171 | |
| 172 | /* Symbols for shared library trampolines are next best. */ |
| 173 | if (trampoline_symbol) |
| 174 | return trampoline_symbol; |
| 175 | |
| 176 | return NULL; |
| 177 | } |
| 178 | |
| 179 | /* Look through all the current minimal symbol tables and find the |
| 180 | first minimal symbol that matches NAME and of text type. |
| 181 | If OBJF is non-NULL, limit |
| 182 | the search to that objfile. If SFILE is non-NULL, limit the search |
| 183 | to that source file. Returns a pointer to the minimal symbol that |
| 184 | matches, or NULL if no match is found. |
| 185 | */ |
| 186 | |
| 187 | struct minimal_symbol * |
| 188 | lookup_minimal_symbol_text (name, sfile, objf) |
| 189 | register const char *name; |
| 190 | const char *sfile; |
| 191 | struct objfile *objf; |
| 192 | { |
| 193 | struct objfile *objfile; |
| 194 | struct minimal_symbol *msymbol; |
| 195 | struct minimal_symbol *found_symbol = NULL; |
| 196 | struct minimal_symbol *found_file_symbol = NULL; |
| 197 | struct minimal_symbol *trampoline_symbol = NULL; |
| 198 | |
| 199 | #ifdef SOFUN_ADDRESS_MAYBE_MISSING |
| 200 | if (sfile != NULL) |
| 201 | { |
| 202 | char *p = strrchr (sfile, '/'); |
| 203 | if (p != NULL) |
| 204 | sfile = p + 1; |
| 205 | } |
| 206 | #endif |
| 207 | |
| 208 | for (objfile = object_files; |
| 209 | objfile != NULL && found_symbol == NULL; |
| 210 | objfile = objfile -> next) |
| 211 | { |
| 212 | if (objf == NULL || objf == objfile) |
| 213 | { |
| 214 | for (msymbol = objfile -> msymbols; |
| 215 | msymbol != NULL && SYMBOL_NAME (msymbol) != NULL && |
| 216 | found_symbol == NULL; |
| 217 | msymbol++) |
| 218 | { |
| 219 | if (SYMBOL_MATCHES_NAME (msymbol, name) && |
| 220 | (MSYMBOL_TYPE (msymbol) == mst_text || |
| 221 | MSYMBOL_TYPE (msymbol) == mst_file_text)) |
| 222 | { |
| 223 | switch (MSYMBOL_TYPE (msymbol)) |
| 224 | { |
| 225 | case mst_file_text: |
| 226 | #ifdef SOFUN_ADDRESS_MAYBE_MISSING |
| 227 | if (sfile == NULL || STREQ (msymbol->filename, sfile)) |
| 228 | found_file_symbol = msymbol; |
| 229 | #else |
| 230 | /* We have neither the ability nor the need to |
| 231 | deal with the SFILE parameter. If we find |
| 232 | more than one symbol, just return the latest |
| 233 | one (the user can't expect useful behavior in |
| 234 | that case). */ |
| 235 | found_file_symbol = msymbol; |
| 236 | #endif |
| 237 | break; |
| 238 | default: |
| 239 | found_symbol = msymbol; |
| 240 | break; |
| 241 | } |
| 242 | } |
| 243 | } |
| 244 | } |
| 245 | } |
| 246 | /* External symbols are best. */ |
| 247 | if (found_symbol) |
| 248 | return found_symbol; |
| 249 | |
| 250 | /* File-local symbols are next best. */ |
| 251 | if (found_file_symbol) |
| 252 | return found_file_symbol; |
| 253 | |
| 254 | return NULL; |
| 255 | } |
| 256 | |
| 257 | |
| 258 | /* Search through the minimal symbol table for each objfile and find the |
| 259 | symbol whose address is the largest address that is still less than or |
| 260 | equal to PC. Returns a pointer to the minimal symbol if such a symbol |
| 261 | is found, or NULL if PC is not in a suitable range. Note that we need |
| 262 | to look through ALL the minimal symbol tables before deciding on the |
| 263 | symbol that comes closest to the specified PC. This is because objfiles |
| 264 | can overlap, for example objfile A has .text at 0x100 and .data at 0x40000 |
| 265 | and objfile B has .text at 0x234 and .data at 0x40048. */ |
| 266 | |
| 267 | struct minimal_symbol * |
| 268 | lookup_minimal_symbol_by_pc (pc) |
| 269 | register CORE_ADDR pc; |
| 270 | { |
| 271 | register int lo; |
| 272 | register int hi; |
| 273 | register int new; |
| 274 | register struct objfile *objfile; |
| 275 | register struct minimal_symbol *msymbol; |
| 276 | register struct minimal_symbol *best_symbol = NULL; |
| 277 | |
| 278 | for (objfile = object_files; |
| 279 | objfile != NULL; |
| 280 | objfile = objfile -> next) |
| 281 | { |
| 282 | /* If this objfile has a minimal symbol table, go search it using |
| 283 | a binary search. Note that a minimal symbol table always consists |
| 284 | of at least two symbols, a "real" symbol and the terminating |
| 285 | "null symbol". If there are no real symbols, then there is no |
| 286 | minimal symbol table at all. */ |
| 287 | |
| 288 | if ((msymbol = objfile -> msymbols) != NULL) |
| 289 | { |
| 290 | lo = 0; |
| 291 | hi = objfile -> minimal_symbol_count - 1; |
| 292 | |
| 293 | /* This code assumes that the minimal symbols are sorted by |
| 294 | ascending address values. If the pc value is greater than or |
| 295 | equal to the first symbol's address, then some symbol in this |
| 296 | minimal symbol table is a suitable candidate for being the |
| 297 | "best" symbol. This includes the last real symbol, for cases |
| 298 | where the pc value is larger than any address in this vector. |
| 299 | |
| 300 | By iterating until the address associated with the current |
| 301 | hi index (the endpoint of the test interval) is less than |
| 302 | or equal to the desired pc value, we accomplish two things: |
| 303 | (1) the case where the pc value is larger than any minimal |
| 304 | symbol address is trivially solved, (2) the address associated |
| 305 | with the hi index is always the one we want when the interation |
| 306 | terminates. In essence, we are iterating the test interval |
| 307 | down until the pc value is pushed out of it from the high end. |
| 308 | |
| 309 | Warning: this code is trickier than it would appear at first. */ |
| 310 | |
| 311 | /* Should also requires that pc is <= end of objfile. FIXME! */ |
| 312 | if (pc >= SYMBOL_VALUE_ADDRESS (&msymbol[lo])) |
| 313 | { |
| 314 | while (SYMBOL_VALUE_ADDRESS (&msymbol[hi]) > pc) |
| 315 | { |
| 316 | /* pc is still strictly less than highest address */ |
| 317 | /* Note "new" will always be >= lo */ |
| 318 | new = (lo + hi) / 2; |
| 319 | if ((SYMBOL_VALUE_ADDRESS (&msymbol[new]) >= pc) || |
| 320 | (lo == new)) |
| 321 | { |
| 322 | hi = new; |
| 323 | } |
| 324 | else |
| 325 | { |
| 326 | lo = new; |
| 327 | } |
| 328 | } |
| 329 | /* The minimal symbol indexed by hi now is the best one in this |
| 330 | objfile's minimal symbol table. See if it is the best one |
| 331 | overall. */ |
| 332 | |
| 333 | /* Skip any absolute symbols. This is apparently what adb |
| 334 | and dbx do, and is needed for the CM-5. There are two |
| 335 | known possible problems: (1) on ELF, apparently end, edata, |
| 336 | etc. are absolute. Not sure ignoring them here is a big |
| 337 | deal, but if we want to use them, the fix would go in |
| 338 | elfread.c. (2) I think shared library entry points on the |
| 339 | NeXT are absolute. If we want special handling for this |
| 340 | it probably should be triggered by a special |
| 341 | mst_abs_or_lib or some such. */ |
| 342 | while (hi >= 0 |
| 343 | && msymbol[hi].type == mst_abs) |
| 344 | --hi; |
| 345 | |
| 346 | if (hi >= 0 |
| 347 | && ((best_symbol == NULL) || |
| 348 | (SYMBOL_VALUE_ADDRESS (best_symbol) < |
| 349 | SYMBOL_VALUE_ADDRESS (&msymbol[hi])))) |
| 350 | { |
| 351 | best_symbol = &msymbol[hi]; |
| 352 | } |
| 353 | } |
| 354 | } |
| 355 | } |
| 356 | return (best_symbol); |
| 357 | } |
| 358 | |
| 359 | #ifdef SOFUN_ADDRESS_MAYBE_MISSING |
| 360 | CORE_ADDR |
| 361 | find_stab_function_addr (namestring, pst, objfile) |
| 362 | char *namestring; |
| 363 | struct partial_symtab *pst; |
| 364 | struct objfile *objfile; |
| 365 | { |
| 366 | struct minimal_symbol *msym; |
| 367 | char *p; |
| 368 | int n; |
| 369 | |
| 370 | p = strchr (namestring, ':'); |
| 371 | if (p == NULL) |
| 372 | p = namestring; |
| 373 | n = p - namestring; |
| 374 | p = alloca (n + 1); |
| 375 | strncpy (p, namestring, n); |
| 376 | p[n] = 0; |
| 377 | |
| 378 | msym = lookup_minimal_symbol (p, pst->filename, objfile); |
| 379 | return msym == NULL ? 0 : SYMBOL_VALUE_ADDRESS (msym); |
| 380 | } |
| 381 | #endif /* SOFUN_ADDRESS_MAYBE_MISSING */ |
| 382 | |
| 383 | \f |
| 384 | /* Return leading symbol character for a BFD. If BFD is NULL, |
| 385 | return the leading symbol character from the main objfile. */ |
| 386 | |
| 387 | static int get_symbol_leading_char PARAMS ((bfd *)); |
| 388 | |
| 389 | static int |
| 390 | get_symbol_leading_char (abfd) |
| 391 | bfd * abfd; |
| 392 | { |
| 393 | if (abfd != NULL) |
| 394 | return bfd_get_symbol_leading_char (abfd); |
| 395 | if (symfile_objfile != NULL && symfile_objfile->obfd != NULL) |
| 396 | return bfd_get_symbol_leading_char (symfile_objfile->obfd); |
| 397 | return 0; |
| 398 | } |
| 399 | |
| 400 | /* Prepare to start collecting minimal symbols. Note that presetting |
| 401 | msym_bunch_index to BUNCH_SIZE causes the first call to save a minimal |
| 402 | symbol to allocate the memory for the first bunch. */ |
| 403 | |
| 404 | void |
| 405 | init_minimal_symbol_collection () |
| 406 | { |
| 407 | msym_count = 0; |
| 408 | msym_bunch = NULL; |
| 409 | msym_bunch_index = BUNCH_SIZE; |
| 410 | } |
| 411 | |
| 412 | void |
| 413 | prim_record_minimal_symbol (name, address, ms_type, objfile) |
| 414 | const char *name; |
| 415 | CORE_ADDR address; |
| 416 | enum minimal_symbol_type ms_type; |
| 417 | struct objfile *objfile; |
| 418 | { |
| 419 | int section; |
| 420 | |
| 421 | switch (ms_type) |
| 422 | { |
| 423 | case mst_text: |
| 424 | case mst_file_text: |
| 425 | case mst_solib_trampoline: |
| 426 | section = SECT_OFF_TEXT; |
| 427 | break; |
| 428 | case mst_data: |
| 429 | case mst_file_data: |
| 430 | section = SECT_OFF_DATA; |
| 431 | break; |
| 432 | case mst_bss: |
| 433 | case mst_file_bss: |
| 434 | section = SECT_OFF_BSS; |
| 435 | break; |
| 436 | default: |
| 437 | section = -1; |
| 438 | } |
| 439 | |
| 440 | prim_record_minimal_symbol_and_info (name, address, ms_type, |
| 441 | NULL, section, objfile); |
| 442 | } |
| 443 | |
| 444 | /* Record a minimal symbol in the msym bunches. Returns the symbol |
| 445 | newly created. */ |
| 446 | struct minimal_symbol * |
| 447 | prim_record_minimal_symbol_and_info (name, address, ms_type, info, section, |
| 448 | objfile) |
| 449 | const char *name; |
| 450 | CORE_ADDR address; |
| 451 | enum minimal_symbol_type ms_type; |
| 452 | char *info; |
| 453 | int section; |
| 454 | struct objfile *objfile; |
| 455 | { |
| 456 | register struct msym_bunch *new; |
| 457 | register struct minimal_symbol *msymbol; |
| 458 | |
| 459 | if (ms_type == mst_file_text) |
| 460 | { |
| 461 | /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into |
| 462 | the minimal symbols, because if there is also another symbol |
| 463 | at the same address (e.g. the first function of the file), |
| 464 | lookup_minimal_symbol_by_pc would have no way of getting the |
| 465 | right one. */ |
| 466 | if (name[0] == 'g' |
| 467 | && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0 |
| 468 | || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0)) |
| 469 | return; |
| 470 | |
| 471 | { |
| 472 | const char *tempstring = name; |
| 473 | if (tempstring[0] == get_symbol_leading_char (objfile->obfd)) |
| 474 | ++tempstring; |
| 475 | if (STREQN (tempstring, "__gnu_compiled", 14)) |
| 476 | return; |
| 477 | } |
| 478 | } |
| 479 | |
| 480 | if (msym_bunch_index == BUNCH_SIZE) |
| 481 | { |
| 482 | new = (struct msym_bunch *) xmalloc (sizeof (struct msym_bunch)); |
| 483 | msym_bunch_index = 0; |
| 484 | new -> next = msym_bunch; |
| 485 | msym_bunch = new; |
| 486 | } |
| 487 | msymbol = &msym_bunch -> contents[msym_bunch_index]; |
| 488 | SYMBOL_NAME (msymbol) = (char *) name; |
| 489 | SYMBOL_INIT_LANGUAGE_SPECIFIC (msymbol, language_unknown); |
| 490 | SYMBOL_VALUE_ADDRESS (msymbol) = address; |
| 491 | SYMBOL_SECTION (msymbol) = section; |
| 492 | |
| 493 | MSYMBOL_TYPE (msymbol) = ms_type; |
| 494 | /* FIXME: This info, if it remains, needs its own field. */ |
| 495 | MSYMBOL_INFO (msymbol) = info; /* FIXME! */ |
| 496 | msym_bunch_index++; |
| 497 | msym_count++; |
| 498 | return msymbol; |
| 499 | } |
| 500 | |
| 501 | /* Compare two minimal symbols by address and return a signed result based |
| 502 | on unsigned comparisons, so that we sort into unsigned numeric order. */ |
| 503 | |
| 504 | static int |
| 505 | compare_minimal_symbols (fn1p, fn2p) |
| 506 | const PTR fn1p; |
| 507 | const PTR fn2p; |
| 508 | { |
| 509 | register const struct minimal_symbol *fn1; |
| 510 | register const struct minimal_symbol *fn2; |
| 511 | |
| 512 | fn1 = (const struct minimal_symbol *) fn1p; |
| 513 | fn2 = (const struct minimal_symbol *) fn2p; |
| 514 | |
| 515 | if (SYMBOL_VALUE_ADDRESS (fn1) < SYMBOL_VALUE_ADDRESS (fn2)) |
| 516 | { |
| 517 | return (-1); |
| 518 | } |
| 519 | else if (SYMBOL_VALUE_ADDRESS (fn1) > SYMBOL_VALUE_ADDRESS (fn2)) |
| 520 | { |
| 521 | return (1); |
| 522 | } |
| 523 | else |
| 524 | { |
| 525 | return (0); |
| 526 | } |
| 527 | } |
| 528 | |
| 529 | /* Discard the currently collected minimal symbols, if any. If we wish |
| 530 | to save them for later use, we must have already copied them somewhere |
| 531 | else before calling this function. |
| 532 | |
| 533 | FIXME: We could allocate the minimal symbol bunches on their own |
| 534 | obstack and then simply blow the obstack away when we are done with |
| 535 | it. Is it worth the extra trouble though? */ |
| 536 | |
| 537 | /* ARGSUSED */ |
| 538 | void |
| 539 | discard_minimal_symbols (foo) |
| 540 | int foo; |
| 541 | { |
| 542 | register struct msym_bunch *next; |
| 543 | |
| 544 | while (msym_bunch != NULL) |
| 545 | { |
| 546 | next = msym_bunch -> next; |
| 547 | free ((PTR)msym_bunch); |
| 548 | msym_bunch = next; |
| 549 | } |
| 550 | } |
| 551 | |
| 552 | /* Compact duplicate entries out of a minimal symbol table by walking |
| 553 | through the table and compacting out entries with duplicate addresses |
| 554 | and matching names. Return the number of entries remaining. |
| 555 | |
| 556 | On entry, the table resides between msymbol[0] and msymbol[mcount]. |
| 557 | On exit, it resides between msymbol[0] and msymbol[result_count]. |
| 558 | |
| 559 | When files contain multiple sources of symbol information, it is |
| 560 | possible for the minimal symbol table to contain many duplicate entries. |
| 561 | As an example, SVR4 systems use ELF formatted object files, which |
| 562 | usually contain at least two different types of symbol tables (a |
| 563 | standard ELF one and a smaller dynamic linking table), as well as |
| 564 | DWARF debugging information for files compiled with -g. |
| 565 | |
| 566 | Without compacting, the minimal symbol table for gdb itself contains |
| 567 | over a 1000 duplicates, about a third of the total table size. Aside |
| 568 | from the potential trap of not noticing that two successive entries |
| 569 | identify the same location, this duplication impacts the time required |
| 570 | to linearly scan the table, which is done in a number of places. So we |
| 571 | just do one linear scan here and toss out the duplicates. |
| 572 | |
| 573 | Note that we are not concerned here about recovering the space that |
| 574 | is potentially freed up, because the strings themselves are allocated |
| 575 | on the symbol_obstack, and will get automatically freed when the symbol |
| 576 | table is freed. The caller can free up the unused minimal symbols at |
| 577 | the end of the compacted region if their allocation strategy allows it. |
| 578 | |
| 579 | Also note we only go up to the next to last entry within the loop |
| 580 | and then copy the last entry explicitly after the loop terminates. |
| 581 | |
| 582 | Since the different sources of information for each symbol may |
| 583 | have different levels of "completeness", we may have duplicates |
| 584 | that have one entry with type "mst_unknown" and the other with a |
| 585 | known type. So if the one we are leaving alone has type mst_unknown, |
| 586 | overwrite its type with the type from the one we are compacting out. */ |
| 587 | |
| 588 | static int |
| 589 | compact_minimal_symbols (msymbol, mcount) |
| 590 | struct minimal_symbol *msymbol; |
| 591 | int mcount; |
| 592 | { |
| 593 | struct minimal_symbol *copyfrom; |
| 594 | struct minimal_symbol *copyto; |
| 595 | |
| 596 | if (mcount > 0) |
| 597 | { |
| 598 | copyfrom = copyto = msymbol; |
| 599 | while (copyfrom < msymbol + mcount - 1) |
| 600 | { |
| 601 | if (SYMBOL_VALUE_ADDRESS (copyfrom) == |
| 602 | SYMBOL_VALUE_ADDRESS ((copyfrom + 1)) && |
| 603 | (STREQ (SYMBOL_NAME (copyfrom), SYMBOL_NAME ((copyfrom + 1))))) |
| 604 | { |
| 605 | if (MSYMBOL_TYPE((copyfrom + 1)) == mst_unknown) |
| 606 | { |
| 607 | MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom); |
| 608 | } |
| 609 | copyfrom++; |
| 610 | } |
| 611 | else |
| 612 | { |
| 613 | *copyto++ = *copyfrom++; |
| 614 | } |
| 615 | } |
| 616 | *copyto++ = *copyfrom++; |
| 617 | mcount = copyto - msymbol; |
| 618 | } |
| 619 | return (mcount); |
| 620 | } |
| 621 | |
| 622 | /* Add the minimal symbols in the existing bunches to the objfile's official |
| 623 | minimal symbol table. In most cases there is no minimal symbol table yet |
| 624 | for this objfile, and the existing bunches are used to create one. Once |
| 625 | in a while (for shared libraries for example), we add symbols (e.g. common |
| 626 | symbols) to an existing objfile. |
| 627 | |
| 628 | Because of the way minimal symbols are collected, we generally have no way |
| 629 | of knowing what source language applies to any particular minimal symbol. |
| 630 | Specifically, we have no way of knowing if the minimal symbol comes from a |
| 631 | C++ compilation unit or not. So for the sake of supporting cached |
| 632 | demangled C++ names, we have no choice but to try and demangle each new one |
| 633 | that comes in. If the demangling succeeds, then we assume it is a C++ |
| 634 | symbol and set the symbol's language and demangled name fields |
| 635 | appropriately. Note that in order to avoid unnecessary demanglings, and |
| 636 | allocating obstack space that subsequently can't be freed for the demangled |
| 637 | names, we mark all newly added symbols with language_auto. After |
| 638 | compaction of the minimal symbols, we go back and scan the entire minimal |
| 639 | symbol table looking for these new symbols. For each new symbol we attempt |
| 640 | to demangle it, and if successful, record it as a language_cplus symbol |
| 641 | and cache the demangled form on the symbol obstack. Symbols which don't |
| 642 | demangle are marked as language_unknown symbols, which inhibits future |
| 643 | attempts to demangle them if we later add more minimal symbols. */ |
| 644 | |
| 645 | void |
| 646 | install_minimal_symbols (objfile) |
| 647 | struct objfile *objfile; |
| 648 | { |
| 649 | register int bindex; |
| 650 | register int mcount; |
| 651 | register struct msym_bunch *bunch; |
| 652 | register struct minimal_symbol *msymbols; |
| 653 | int alloc_count; |
| 654 | register char leading_char; |
| 655 | |
| 656 | if (msym_count > 0) |
| 657 | { |
| 658 | /* Allocate enough space in the obstack, into which we will gather the |
| 659 | bunches of new and existing minimal symbols, sort them, and then |
| 660 | compact out the duplicate entries. Once we have a final table, |
| 661 | we will give back the excess space. */ |
| 662 | |
| 663 | alloc_count = msym_count + objfile->minimal_symbol_count + 1; |
| 664 | obstack_blank (&objfile->symbol_obstack, |
| 665 | alloc_count * sizeof (struct minimal_symbol)); |
| 666 | msymbols = (struct minimal_symbol *) |
| 667 | obstack_base (&objfile->symbol_obstack); |
| 668 | |
| 669 | /* Copy in the existing minimal symbols, if there are any. */ |
| 670 | |
| 671 | if (objfile->minimal_symbol_count) |
| 672 | memcpy ((char *)msymbols, (char *)objfile->msymbols, |
| 673 | objfile->minimal_symbol_count * sizeof (struct minimal_symbol)); |
| 674 | |
| 675 | /* Walk through the list of minimal symbol bunches, adding each symbol |
| 676 | to the new contiguous array of symbols. Note that we start with the |
| 677 | current, possibly partially filled bunch (thus we use the current |
| 678 | msym_bunch_index for the first bunch we copy over), and thereafter |
| 679 | each bunch is full. */ |
| 680 | |
| 681 | mcount = objfile->minimal_symbol_count; |
| 682 | leading_char = get_symbol_leading_char (objfile->obfd); |
| 683 | |
| 684 | for (bunch = msym_bunch; bunch != NULL; bunch = bunch -> next) |
| 685 | { |
| 686 | for (bindex = 0; bindex < msym_bunch_index; bindex++, mcount++) |
| 687 | { |
| 688 | msymbols[mcount] = bunch -> contents[bindex]; |
| 689 | SYMBOL_LANGUAGE (&msymbols[mcount]) = language_auto; |
| 690 | if (SYMBOL_NAME (&msymbols[mcount])[0] == leading_char) |
| 691 | { |
| 692 | SYMBOL_NAME(&msymbols[mcount])++; |
| 693 | } |
| 694 | } |
| 695 | msym_bunch_index = BUNCH_SIZE; |
| 696 | } |
| 697 | |
| 698 | /* Sort the minimal symbols by address. */ |
| 699 | |
| 700 | qsort (msymbols, mcount, sizeof (struct minimal_symbol), |
| 701 | compare_minimal_symbols); |
| 702 | |
| 703 | /* Compact out any duplicates, and free up whatever space we are |
| 704 | no longer using. */ |
| 705 | |
| 706 | mcount = compact_minimal_symbols (msymbols, mcount); |
| 707 | |
| 708 | obstack_blank (&objfile->symbol_obstack, |
| 709 | (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol)); |
| 710 | msymbols = (struct minimal_symbol *) |
| 711 | obstack_finish (&objfile->symbol_obstack); |
| 712 | |
| 713 | /* We also terminate the minimal symbol table with a "null symbol", |
| 714 | which is *not* included in the size of the table. This makes it |
| 715 | easier to find the end of the table when we are handed a pointer |
| 716 | to some symbol in the middle of it. Zero out the fields in the |
| 717 | "null symbol" allocated at the end of the array. Note that the |
| 718 | symbol count does *not* include this null symbol, which is why it |
| 719 | is indexed by mcount and not mcount-1. */ |
| 720 | |
| 721 | SYMBOL_NAME (&msymbols[mcount]) = NULL; |
| 722 | SYMBOL_VALUE_ADDRESS (&msymbols[mcount]) = 0; |
| 723 | MSYMBOL_INFO (&msymbols[mcount]) = NULL; |
| 724 | MSYMBOL_TYPE (&msymbols[mcount]) = mst_unknown; |
| 725 | SYMBOL_INIT_LANGUAGE_SPECIFIC (&msymbols[mcount], language_unknown); |
| 726 | |
| 727 | /* Attach the minimal symbol table to the specified objfile. |
| 728 | The strings themselves are also located in the symbol_obstack |
| 729 | of this objfile. */ |
| 730 | |
| 731 | objfile -> minimal_symbol_count = mcount; |
| 732 | objfile -> msymbols = msymbols; |
| 733 | |
| 734 | /* Now walk through all the minimal symbols, selecting the newly added |
| 735 | ones and attempting to cache their C++ demangled names. */ |
| 736 | |
| 737 | for ( ; mcount-- > 0 ; msymbols++) |
| 738 | { |
| 739 | SYMBOL_INIT_DEMANGLED_NAME (msymbols, &objfile->symbol_obstack); |
| 740 | } |
| 741 | } |
| 742 | } |
| 743 | |
| 744 | /* Sort all the minimal symbols in OBJFILE. */ |
| 745 | |
| 746 | void |
| 747 | msymbols_sort (objfile) |
| 748 | struct objfile *objfile; |
| 749 | { |
| 750 | qsort (objfile->msymbols, objfile->minimal_symbol_count, |
| 751 | sizeof (struct minimal_symbol), compare_minimal_symbols); |
| 752 | } |
| 753 | |
| 754 | /* Check if PC is in a shared library trampoline code stub. |
| 755 | Return minimal symbol for the trampoline entry or NULL if PC is not |
| 756 | in a trampoline code stub. */ |
| 757 | |
| 758 | struct minimal_symbol * |
| 759 | lookup_solib_trampoline_symbol_by_pc (pc) |
| 760 | CORE_ADDR pc; |
| 761 | { |
| 762 | struct minimal_symbol *msymbol = lookup_minimal_symbol_by_pc (pc); |
| 763 | |
| 764 | if (msymbol != NULL && MSYMBOL_TYPE (msymbol) == mst_solib_trampoline) |
| 765 | return msymbol; |
| 766 | return NULL; |
| 767 | } |
| 768 | |
| 769 | /* If PC is in a shared library trampoline code stub, return the |
| 770 | address of the `real' function belonging to the stub. |
| 771 | Return 0 if PC is not in a trampoline code stub or if the real |
| 772 | function is not found in the minimal symbol table. |
| 773 | |
| 774 | We may fail to find the right function if a function with the |
| 775 | same name is defined in more than one shared library, but this |
| 776 | is considered bad programming style. We could return 0 if we find |
| 777 | a duplicate function in case this matters someday. */ |
| 778 | |
| 779 | CORE_ADDR |
| 780 | find_solib_trampoline_target (pc) |
| 781 | CORE_ADDR pc; |
| 782 | { |
| 783 | struct objfile *objfile; |
| 784 | struct minimal_symbol *msymbol; |
| 785 | struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc); |
| 786 | |
| 787 | if (tsymbol != NULL) |
| 788 | { |
| 789 | ALL_MSYMBOLS (objfile, msymbol) |
| 790 | { |
| 791 | if (MSYMBOL_TYPE (msymbol) == mst_text |
| 792 | && STREQ (SYMBOL_NAME (msymbol), SYMBOL_NAME (tsymbol))) |
| 793 | return SYMBOL_VALUE_ADDRESS (msymbol); |
| 794 | } |
| 795 | } |
| 796 | return 0; |
| 797 | } |
| 798 | |