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c906108c SS |
1 | /* GDB routines for manipulating the minimal symbol tables. |
2 | Copyright 1992, 93, 94, 96, 97, 1998 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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 "gdb_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 | ||
198 | #ifdef SOFUN_ADDRESS_MAYBE_MISSING | |
199 | if (sfile != NULL) | |
200 | { | |
201 | char *p = strrchr (sfile, '/'); | |
202 | if (p != NULL) | |
203 | sfile = p + 1; | |
204 | } | |
205 | #endif | |
206 | ||
207 | for (objfile = object_files; | |
208 | objfile != NULL && found_symbol == NULL; | |
209 | objfile = objfile -> next) | |
210 | { | |
211 | if (objf == NULL || objf == objfile) | |
212 | { | |
213 | for (msymbol = objfile -> msymbols; | |
214 | msymbol != NULL && SYMBOL_NAME (msymbol) != NULL && | |
215 | found_symbol == NULL; | |
216 | msymbol++) | |
217 | { | |
218 | if (SYMBOL_MATCHES_NAME (msymbol, name) && | |
219 | (MSYMBOL_TYPE (msymbol) == mst_text || | |
220 | MSYMBOL_TYPE (msymbol) == mst_file_text)) | |
221 | { | |
222 | switch (MSYMBOL_TYPE (msymbol)) | |
223 | { | |
224 | case mst_file_text: | |
225 | #ifdef SOFUN_ADDRESS_MAYBE_MISSING | |
226 | if (sfile == NULL || STREQ (msymbol->filename, sfile)) | |
227 | found_file_symbol = msymbol; | |
228 | #else | |
229 | /* We have neither the ability nor the need to | |
230 | deal with the SFILE parameter. If we find | |
231 | more than one symbol, just return the latest | |
232 | one (the user can't expect useful behavior in | |
233 | that case). */ | |
234 | found_file_symbol = msymbol; | |
235 | #endif | |
236 | break; | |
237 | default: | |
238 | found_symbol = msymbol; | |
239 | break; | |
240 | } | |
241 | } | |
242 | } | |
243 | } | |
244 | } | |
245 | /* External symbols are best. */ | |
246 | if (found_symbol) | |
247 | return found_symbol; | |
248 | ||
249 | /* File-local symbols are next best. */ | |
250 | if (found_file_symbol) | |
251 | return found_file_symbol; | |
252 | ||
253 | return NULL; | |
254 | } | |
255 | ||
256 | /* Look through all the current minimal symbol tables and find the | |
257 | first minimal symbol that matches NAME and of solib trampoline type. | |
258 | If OBJF is non-NULL, limit | |
259 | the search to that objfile. If SFILE is non-NULL, limit the search | |
260 | to that source file. Returns a pointer to the minimal symbol that | |
261 | matches, or NULL if no match is found. | |
262 | */ | |
263 | ||
264 | struct minimal_symbol * | |
265 | lookup_minimal_symbol_solib_trampoline (name, sfile, objf) | |
266 | register const char *name; | |
267 | const char *sfile; | |
268 | struct objfile *objf; | |
269 | { | |
270 | struct objfile *objfile; | |
271 | struct minimal_symbol *msymbol; | |
272 | struct minimal_symbol *found_symbol = NULL; | |
273 | ||
274 | #ifdef SOFUN_ADDRESS_MAYBE_MISSING | |
275 | if (sfile != NULL) | |
276 | { | |
277 | char *p = strrchr (sfile, '/'); | |
278 | if (p != NULL) | |
279 | sfile = p + 1; | |
280 | } | |
281 | #endif | |
282 | ||
283 | for (objfile = object_files; | |
284 | objfile != NULL && found_symbol == NULL; | |
285 | objfile = objfile -> next) | |
286 | { | |
287 | if (objf == NULL || objf == objfile) | |
288 | { | |
289 | for (msymbol = objfile -> msymbols; | |
290 | msymbol != NULL && SYMBOL_NAME (msymbol) != NULL && | |
291 | found_symbol == NULL; | |
292 | msymbol++) | |
293 | { | |
294 | if (SYMBOL_MATCHES_NAME (msymbol, name) && | |
295 | MSYMBOL_TYPE (msymbol) == mst_solib_trampoline) | |
296 | return msymbol; | |
297 | } | |
298 | } | |
299 | } | |
300 | ||
301 | return NULL; | |
302 | } | |
303 | ||
304 | ||
305 | /* Search through the minimal symbol table for each objfile and find | |
306 | the symbol whose address is the largest address that is still less | |
307 | than or equal to PC, and matches SECTION (if non-null). Returns a | |
308 | pointer to the minimal symbol if such a symbol is found, or NULL if | |
309 | PC is not in a suitable range. Note that we need to look through | |
310 | ALL the minimal symbol tables before deciding on the symbol that | |
311 | comes closest to the specified PC. This is because objfiles can | |
312 | overlap, for example objfile A has .text at 0x100 and .data at | |
313 | 0x40000 and objfile B has .text at 0x234 and .data at 0x40048. */ | |
314 | ||
315 | struct minimal_symbol * | |
316 | lookup_minimal_symbol_by_pc_section (pc, section) | |
317 | CORE_ADDR pc; | |
318 | asection *section; | |
319 | { | |
320 | int lo; | |
321 | int hi; | |
322 | int new; | |
323 | struct objfile *objfile; | |
324 | struct minimal_symbol *msymbol; | |
325 | struct minimal_symbol *best_symbol = NULL; | |
326 | ||
327 | /* pc has to be in a known section. This ensures that anything beyond | |
328 | the end of the last segment doesn't appear to be part of the last | |
329 | function in the last segment. */ | |
330 | if (find_pc_section (pc) == NULL) | |
331 | return NULL; | |
332 | ||
333 | for (objfile = object_files; | |
334 | objfile != NULL; | |
335 | objfile = objfile -> next) | |
336 | { | |
337 | /* If this objfile has a minimal symbol table, go search it using | |
338 | a binary search. Note that a minimal symbol table always consists | |
339 | of at least two symbols, a "real" symbol and the terminating | |
340 | "null symbol". If there are no real symbols, then there is no | |
341 | minimal symbol table at all. */ | |
342 | ||
343 | if ((msymbol = objfile -> msymbols) != NULL) | |
344 | { | |
345 | lo = 0; | |
346 | hi = objfile -> minimal_symbol_count - 1; | |
347 | ||
348 | /* This code assumes that the minimal symbols are sorted by | |
349 | ascending address values. If the pc value is greater than or | |
350 | equal to the first symbol's address, then some symbol in this | |
351 | minimal symbol table is a suitable candidate for being the | |
352 | "best" symbol. This includes the last real symbol, for cases | |
353 | where the pc value is larger than any address in this vector. | |
354 | ||
355 | By iterating until the address associated with the current | |
356 | hi index (the endpoint of the test interval) is less than | |
357 | or equal to the desired pc value, we accomplish two things: | |
358 | (1) the case where the pc value is larger than any minimal | |
359 | symbol address is trivially solved, (2) the address associated | |
360 | with the hi index is always the one we want when the interation | |
361 | terminates. In essence, we are iterating the test interval | |
362 | down until the pc value is pushed out of it from the high end. | |
363 | ||
364 | Warning: this code is trickier than it would appear at first. */ | |
365 | ||
366 | /* Should also require that pc is <= end of objfile. FIXME! */ | |
367 | if (pc >= SYMBOL_VALUE_ADDRESS (&msymbol[lo])) | |
368 | { | |
369 | while (SYMBOL_VALUE_ADDRESS (&msymbol[hi]) > pc) | |
370 | { | |
371 | /* pc is still strictly less than highest address */ | |
372 | /* Note "new" will always be >= lo */ | |
373 | new = (lo + hi) / 2; | |
374 | if ((SYMBOL_VALUE_ADDRESS (&msymbol[new]) >= pc) || | |
375 | (lo == new)) | |
376 | { | |
377 | hi = new; | |
378 | } | |
379 | else | |
380 | { | |
381 | lo = new; | |
382 | } | |
383 | } | |
384 | ||
385 | /* If we have multiple symbols at the same address, we want | |
386 | hi to point to the last one. That way we can find the | |
387 | right symbol if it has an index greater than hi. */ | |
388 | while (hi < objfile -> minimal_symbol_count - 1 | |
389 | && (SYMBOL_VALUE_ADDRESS (&msymbol[hi]) | |
390 | == SYMBOL_VALUE_ADDRESS (&msymbol[hi+1]))) | |
391 | hi++; | |
392 | ||
393 | /* The minimal symbol indexed by hi now is the best one in this | |
394 | objfile's minimal symbol table. See if it is the best one | |
395 | overall. */ | |
396 | ||
397 | /* Skip any absolute symbols. This is apparently what adb | |
398 | and dbx do, and is needed for the CM-5. There are two | |
399 | known possible problems: (1) on ELF, apparently end, edata, | |
400 | etc. are absolute. Not sure ignoring them here is a big | |
401 | deal, but if we want to use them, the fix would go in | |
402 | elfread.c. (2) I think shared library entry points on the | |
403 | NeXT are absolute. If we want special handling for this | |
404 | it probably should be triggered by a special | |
405 | mst_abs_or_lib or some such. */ | |
406 | while (hi >= 0 | |
407 | && msymbol[hi].type == mst_abs) | |
408 | --hi; | |
409 | ||
410 | /* If "section" specified, skip any symbol from wrong section */ | |
411 | /* This is the new code that distinguishes it from the old function */ | |
412 | if (section) | |
413 | while (hi >= 0 | |
414 | && SYMBOL_BFD_SECTION (&msymbol[hi]) != section) | |
415 | --hi; | |
416 | ||
417 | if (hi >= 0 | |
418 | && ((best_symbol == NULL) || | |
419 | (SYMBOL_VALUE_ADDRESS (best_symbol) < | |
420 | SYMBOL_VALUE_ADDRESS (&msymbol[hi])))) | |
421 | { | |
422 | best_symbol = &msymbol[hi]; | |
423 | } | |
424 | } | |
425 | } | |
426 | } | |
427 | return (best_symbol); | |
428 | } | |
429 | ||
430 | /* Backward compatibility: search through the minimal symbol table | |
431 | for a matching PC (no section given) */ | |
432 | ||
433 | struct minimal_symbol * | |
434 | lookup_minimal_symbol_by_pc (pc) | |
435 | CORE_ADDR pc; | |
436 | { | |
437 | return lookup_minimal_symbol_by_pc_section (pc, find_pc_mapped_section (pc)); | |
438 | } | |
439 | ||
440 | #ifdef SOFUN_ADDRESS_MAYBE_MISSING | |
441 | CORE_ADDR | |
442 | find_stab_function_addr (namestring, pst, objfile) | |
443 | char *namestring; | |
444 | struct partial_symtab *pst; | |
445 | struct objfile *objfile; | |
446 | { | |
447 | struct minimal_symbol *msym; | |
448 | char *p; | |
449 | int n; | |
450 | ||
451 | p = strchr (namestring, ':'); | |
452 | if (p == NULL) | |
453 | p = namestring; | |
454 | n = p - namestring; | |
455 | p = alloca (n + 2); | |
456 | strncpy (p, namestring, n); | |
457 | p[n] = 0; | |
458 | ||
459 | msym = lookup_minimal_symbol (p, pst->filename, objfile); | |
460 | if (msym == NULL) | |
461 | { | |
462 | /* Sun Fortran appends an underscore to the minimal symbol name, | |
463 | try again with an appended underscore if the minimal symbol | |
464 | was not found. */ | |
465 | p[n] = '_'; | |
466 | p[n + 1] = 0; | |
467 | msym = lookup_minimal_symbol (p, pst->filename, objfile); | |
468 | } | |
469 | return msym == NULL ? 0 : SYMBOL_VALUE_ADDRESS (msym); | |
470 | } | |
471 | #endif /* SOFUN_ADDRESS_MAYBE_MISSING */ | |
472 | ||
473 | \f | |
474 | /* Return leading symbol character for a BFD. If BFD is NULL, | |
475 | return the leading symbol character from the main objfile. */ | |
476 | ||
477 | static int get_symbol_leading_char PARAMS ((bfd *)); | |
478 | ||
479 | static int | |
480 | get_symbol_leading_char (abfd) | |
481 | bfd * abfd; | |
482 | { | |
483 | if (abfd != NULL) | |
484 | return bfd_get_symbol_leading_char (abfd); | |
485 | if (symfile_objfile != NULL && symfile_objfile->obfd != NULL) | |
486 | return bfd_get_symbol_leading_char (symfile_objfile->obfd); | |
487 | return 0; | |
488 | } | |
489 | ||
490 | /* Prepare to start collecting minimal symbols. Note that presetting | |
491 | msym_bunch_index to BUNCH_SIZE causes the first call to save a minimal | |
492 | symbol to allocate the memory for the first bunch. */ | |
493 | ||
494 | void | |
495 | init_minimal_symbol_collection () | |
496 | { | |
497 | msym_count = 0; | |
498 | msym_bunch = NULL; | |
499 | msym_bunch_index = BUNCH_SIZE; | |
500 | } | |
501 | ||
502 | void | |
503 | prim_record_minimal_symbol (name, address, ms_type, objfile) | |
504 | const char *name; | |
505 | CORE_ADDR address; | |
506 | enum minimal_symbol_type ms_type; | |
507 | struct objfile *objfile; | |
508 | { | |
509 | int section; | |
510 | ||
511 | switch (ms_type) | |
512 | { | |
513 | case mst_text: | |
514 | case mst_file_text: | |
515 | case mst_solib_trampoline: | |
516 | section = SECT_OFF_TEXT; | |
517 | break; | |
518 | case mst_data: | |
519 | case mst_file_data: | |
520 | section = SECT_OFF_DATA; | |
521 | break; | |
522 | case mst_bss: | |
523 | case mst_file_bss: | |
524 | section = SECT_OFF_BSS; | |
525 | break; | |
526 | default: | |
527 | section = -1; | |
528 | } | |
529 | ||
530 | prim_record_minimal_symbol_and_info (name, address, ms_type, | |
531 | NULL, section, NULL, objfile); | |
532 | } | |
533 | ||
534 | /* Record a minimal symbol in the msym bunches. Returns the symbol | |
535 | newly created. */ | |
536 | ||
537 | struct minimal_symbol * | |
538 | prim_record_minimal_symbol_and_info (name, address, ms_type, info, section, | |
539 | bfd_section, objfile) | |
540 | const char *name; | |
541 | CORE_ADDR address; | |
542 | enum minimal_symbol_type ms_type; | |
543 | char *info; | |
544 | int section; | |
545 | asection *bfd_section; | |
546 | struct objfile *objfile; | |
547 | { | |
548 | register struct msym_bunch *new; | |
549 | register struct minimal_symbol *msymbol; | |
550 | ||
551 | if (ms_type == mst_file_text) | |
552 | { | |
553 | /* Don't put gcc_compiled, __gnu_compiled_cplus, and friends into | |
554 | the minimal symbols, because if there is also another symbol | |
555 | at the same address (e.g. the first function of the file), | |
556 | lookup_minimal_symbol_by_pc would have no way of getting the | |
557 | right one. */ | |
558 | if (name[0] == 'g' | |
559 | && (strcmp (name, GCC_COMPILED_FLAG_SYMBOL) == 0 | |
560 | || strcmp (name, GCC2_COMPILED_FLAG_SYMBOL) == 0)) | |
561 | return (NULL); | |
562 | ||
563 | { | |
564 | const char *tempstring = name; | |
565 | if (tempstring[0] == get_symbol_leading_char (objfile->obfd)) | |
566 | ++tempstring; | |
567 | if (STREQN (tempstring, "__gnu_compiled", 14)) | |
568 | return (NULL); | |
569 | } | |
570 | } | |
571 | ||
572 | if (msym_bunch_index == BUNCH_SIZE) | |
573 | { | |
574 | new = (struct msym_bunch *) xmalloc (sizeof (struct msym_bunch)); | |
575 | msym_bunch_index = 0; | |
576 | new -> next = msym_bunch; | |
577 | msym_bunch = new; | |
578 | } | |
579 | msymbol = &msym_bunch -> contents[msym_bunch_index]; | |
580 | SYMBOL_NAME (msymbol) = obsavestring ((char *) name, strlen (name), | |
581 | &objfile->symbol_obstack); | |
582 | SYMBOL_INIT_LANGUAGE_SPECIFIC (msymbol, language_unknown); | |
583 | SYMBOL_VALUE_ADDRESS (msymbol) = address; | |
584 | SYMBOL_SECTION (msymbol) = section; | |
585 | SYMBOL_BFD_SECTION (msymbol) = bfd_section; | |
586 | ||
587 | MSYMBOL_TYPE (msymbol) = ms_type; | |
588 | /* FIXME: This info, if it remains, needs its own field. */ | |
589 | MSYMBOL_INFO (msymbol) = info; /* FIXME! */ | |
590 | msym_bunch_index++; | |
591 | msym_count++; | |
592 | OBJSTAT (objfile, n_minsyms++); | |
593 | return msymbol; | |
594 | } | |
595 | ||
596 | /* Compare two minimal symbols by address and return a signed result based | |
597 | on unsigned comparisons, so that we sort into unsigned numeric order. | |
598 | Within groups with the same address, sort by name. */ | |
599 | ||
600 | static int | |
601 | compare_minimal_symbols (fn1p, fn2p) | |
602 | const PTR fn1p; | |
603 | const PTR fn2p; | |
604 | { | |
605 | register const struct minimal_symbol *fn1; | |
606 | register const struct minimal_symbol *fn2; | |
607 | ||
608 | fn1 = (const struct minimal_symbol *) fn1p; | |
609 | fn2 = (const struct minimal_symbol *) fn2p; | |
610 | ||
611 | if (SYMBOL_VALUE_ADDRESS (fn1) < SYMBOL_VALUE_ADDRESS (fn2)) | |
612 | { | |
613 | return (-1); /* addr 1 is less than addr 2 */ | |
614 | } | |
615 | else if (SYMBOL_VALUE_ADDRESS (fn1) > SYMBOL_VALUE_ADDRESS (fn2)) | |
616 | { | |
617 | return (1); /* addr 1 is greater than addr 2 */ | |
618 | } | |
619 | else /* addrs are equal: sort by name */ | |
620 | { | |
621 | char *name1 = SYMBOL_NAME (fn1); | |
622 | char *name2 = SYMBOL_NAME (fn2); | |
623 | ||
624 | if (name1 && name2) /* both have names */ | |
625 | return strcmp (name1, name2); | |
626 | else if (name2) | |
627 | return 1; /* fn1 has no name, so it is "less" */ | |
628 | else if (name1) /* fn2 has no name, so it is "less" */ | |
629 | return -1; | |
630 | else | |
631 | return (0); /* neither has a name, so they're equal. */ | |
632 | } | |
633 | } | |
634 | ||
635 | /* Discard the currently collected minimal symbols, if any. If we wish | |
636 | to save them for later use, we must have already copied them somewhere | |
637 | else before calling this function. | |
638 | ||
639 | FIXME: We could allocate the minimal symbol bunches on their own | |
640 | obstack and then simply blow the obstack away when we are done with | |
641 | it. Is it worth the extra trouble though? */ | |
642 | ||
643 | /* ARGSUSED */ | |
644 | void | |
645 | discard_minimal_symbols (foo) | |
646 | int foo; | |
647 | { | |
648 | register struct msym_bunch *next; | |
649 | ||
650 | while (msym_bunch != NULL) | |
651 | { | |
652 | next = msym_bunch -> next; | |
653 | free ((PTR)msym_bunch); | |
654 | msym_bunch = next; | |
655 | } | |
656 | } | |
657 | ||
658 | /* Compact duplicate entries out of a minimal symbol table by walking | |
659 | through the table and compacting out entries with duplicate addresses | |
660 | and matching names. Return the number of entries remaining. | |
661 | ||
662 | On entry, the table resides between msymbol[0] and msymbol[mcount]. | |
663 | On exit, it resides between msymbol[0] and msymbol[result_count]. | |
664 | ||
665 | When files contain multiple sources of symbol information, it is | |
666 | possible for the minimal symbol table to contain many duplicate entries. | |
667 | As an example, SVR4 systems use ELF formatted object files, which | |
668 | usually contain at least two different types of symbol tables (a | |
669 | standard ELF one and a smaller dynamic linking table), as well as | |
670 | DWARF debugging information for files compiled with -g. | |
671 | ||
672 | Without compacting, the minimal symbol table for gdb itself contains | |
673 | over a 1000 duplicates, about a third of the total table size. Aside | |
674 | from the potential trap of not noticing that two successive entries | |
675 | identify the same location, this duplication impacts the time required | |
676 | to linearly scan the table, which is done in a number of places. So we | |
677 | just do one linear scan here and toss out the duplicates. | |
678 | ||
679 | Note that we are not concerned here about recovering the space that | |
680 | is potentially freed up, because the strings themselves are allocated | |
681 | on the symbol_obstack, and will get automatically freed when the symbol | |
682 | table is freed. The caller can free up the unused minimal symbols at | |
683 | the end of the compacted region if their allocation strategy allows it. | |
684 | ||
685 | Also note we only go up to the next to last entry within the loop | |
686 | and then copy the last entry explicitly after the loop terminates. | |
687 | ||
688 | Since the different sources of information for each symbol may | |
689 | have different levels of "completeness", we may have duplicates | |
690 | that have one entry with type "mst_unknown" and the other with a | |
691 | known type. So if the one we are leaving alone has type mst_unknown, | |
692 | overwrite its type with the type from the one we are compacting out. */ | |
693 | ||
694 | static int | |
695 | compact_minimal_symbols (msymbol, mcount) | |
696 | struct minimal_symbol *msymbol; | |
697 | int mcount; | |
698 | { | |
699 | struct minimal_symbol *copyfrom; | |
700 | struct minimal_symbol *copyto; | |
701 | ||
702 | if (mcount > 0) | |
703 | { | |
704 | copyfrom = copyto = msymbol; | |
705 | while (copyfrom < msymbol + mcount - 1) | |
706 | { | |
707 | if (SYMBOL_VALUE_ADDRESS (copyfrom) == | |
708 | SYMBOL_VALUE_ADDRESS ((copyfrom + 1)) && | |
709 | (STREQ (SYMBOL_NAME (copyfrom), SYMBOL_NAME ((copyfrom + 1))))) | |
710 | { | |
711 | if (MSYMBOL_TYPE((copyfrom + 1)) == mst_unknown) | |
712 | { | |
713 | MSYMBOL_TYPE ((copyfrom + 1)) = MSYMBOL_TYPE (copyfrom); | |
714 | } | |
715 | copyfrom++; | |
716 | } | |
717 | else | |
718 | { | |
719 | *copyto++ = *copyfrom++; | |
720 | } | |
721 | } | |
722 | *copyto++ = *copyfrom++; | |
723 | mcount = copyto - msymbol; | |
724 | } | |
725 | return (mcount); | |
726 | } | |
727 | ||
728 | /* Add the minimal symbols in the existing bunches to the objfile's official | |
729 | minimal symbol table. In most cases there is no minimal symbol table yet | |
730 | for this objfile, and the existing bunches are used to create one. Once | |
731 | in a while (for shared libraries for example), we add symbols (e.g. common | |
732 | symbols) to an existing objfile. | |
733 | ||
734 | Because of the way minimal symbols are collected, we generally have no way | |
735 | of knowing what source language applies to any particular minimal symbol. | |
736 | Specifically, we have no way of knowing if the minimal symbol comes from a | |
737 | C++ compilation unit or not. So for the sake of supporting cached | |
738 | demangled C++ names, we have no choice but to try and demangle each new one | |
739 | that comes in. If the demangling succeeds, then we assume it is a C++ | |
740 | symbol and set the symbol's language and demangled name fields | |
741 | appropriately. Note that in order to avoid unnecessary demanglings, and | |
742 | allocating obstack space that subsequently can't be freed for the demangled | |
743 | names, we mark all newly added symbols with language_auto. After | |
744 | compaction of the minimal symbols, we go back and scan the entire minimal | |
745 | symbol table looking for these new symbols. For each new symbol we attempt | |
746 | to demangle it, and if successful, record it as a language_cplus symbol | |
747 | and cache the demangled form on the symbol obstack. Symbols which don't | |
748 | demangle are marked as language_unknown symbols, which inhibits future | |
749 | attempts to demangle them if we later add more minimal symbols. */ | |
750 | ||
751 | void | |
752 | install_minimal_symbols (objfile) | |
753 | struct objfile *objfile; | |
754 | { | |
755 | register int bindex; | |
756 | register int mcount; | |
757 | register struct msym_bunch *bunch; | |
758 | register struct minimal_symbol *msymbols; | |
759 | int alloc_count; | |
760 | register char leading_char; | |
761 | ||
762 | if (msym_count > 0) | |
763 | { | |
764 | /* Allocate enough space in the obstack, into which we will gather the | |
765 | bunches of new and existing minimal symbols, sort them, and then | |
766 | compact out the duplicate entries. Once we have a final table, | |
767 | we will give back the excess space. */ | |
768 | ||
769 | alloc_count = msym_count + objfile->minimal_symbol_count + 1; | |
770 | obstack_blank (&objfile->symbol_obstack, | |
771 | alloc_count * sizeof (struct minimal_symbol)); | |
772 | msymbols = (struct minimal_symbol *) | |
773 | obstack_base (&objfile->symbol_obstack); | |
774 | ||
775 | /* Copy in the existing minimal symbols, if there are any. */ | |
776 | ||
777 | if (objfile->minimal_symbol_count) | |
778 | memcpy ((char *)msymbols, (char *)objfile->msymbols, | |
779 | objfile->minimal_symbol_count * sizeof (struct minimal_symbol)); | |
780 | ||
781 | /* Walk through the list of minimal symbol bunches, adding each symbol | |
782 | to the new contiguous array of symbols. Note that we start with the | |
783 | current, possibly partially filled bunch (thus we use the current | |
784 | msym_bunch_index for the first bunch we copy over), and thereafter | |
785 | each bunch is full. */ | |
786 | ||
787 | mcount = objfile->minimal_symbol_count; | |
788 | leading_char = get_symbol_leading_char (objfile->obfd); | |
789 | ||
790 | for (bunch = msym_bunch; bunch != NULL; bunch = bunch -> next) | |
791 | { | |
792 | for (bindex = 0; bindex < msym_bunch_index; bindex++, mcount++) | |
793 | { | |
794 | msymbols[mcount] = bunch -> contents[bindex]; | |
795 | SYMBOL_LANGUAGE (&msymbols[mcount]) = language_auto; | |
796 | if (SYMBOL_NAME (&msymbols[mcount])[0] == leading_char) | |
797 | { | |
798 | SYMBOL_NAME(&msymbols[mcount])++; | |
799 | } | |
800 | } | |
801 | msym_bunch_index = BUNCH_SIZE; | |
802 | } | |
803 | ||
804 | /* Sort the minimal symbols by address. */ | |
805 | ||
806 | qsort (msymbols, mcount, sizeof (struct minimal_symbol), | |
807 | compare_minimal_symbols); | |
808 | ||
809 | /* Compact out any duplicates, and free up whatever space we are | |
810 | no longer using. */ | |
811 | ||
812 | mcount = compact_minimal_symbols (msymbols, mcount); | |
813 | ||
814 | obstack_blank (&objfile->symbol_obstack, | |
815 | (mcount + 1 - alloc_count) * sizeof (struct minimal_symbol)); | |
816 | msymbols = (struct minimal_symbol *) | |
817 | obstack_finish (&objfile->symbol_obstack); | |
818 | ||
819 | /* We also terminate the minimal symbol table with a "null symbol", | |
820 | which is *not* included in the size of the table. This makes it | |
821 | easier to find the end of the table when we are handed a pointer | |
822 | to some symbol in the middle of it. Zero out the fields in the | |
823 | "null symbol" allocated at the end of the array. Note that the | |
824 | symbol count does *not* include this null symbol, which is why it | |
825 | is indexed by mcount and not mcount-1. */ | |
826 | ||
827 | SYMBOL_NAME (&msymbols[mcount]) = NULL; | |
828 | SYMBOL_VALUE_ADDRESS (&msymbols[mcount]) = 0; | |
829 | MSYMBOL_INFO (&msymbols[mcount]) = NULL; | |
830 | MSYMBOL_TYPE (&msymbols[mcount]) = mst_unknown; | |
831 | SYMBOL_INIT_LANGUAGE_SPECIFIC (&msymbols[mcount], language_unknown); | |
832 | ||
833 | /* Attach the minimal symbol table to the specified objfile. | |
834 | The strings themselves are also located in the symbol_obstack | |
835 | of this objfile. */ | |
836 | ||
837 | objfile -> minimal_symbol_count = mcount; | |
838 | objfile -> msymbols = msymbols; | |
839 | ||
840 | /* Now walk through all the minimal symbols, selecting the newly added | |
841 | ones and attempting to cache their C++ demangled names. */ | |
842 | ||
843 | for ( ; mcount-- > 0 ; msymbols++) | |
844 | { | |
845 | SYMBOL_INIT_DEMANGLED_NAME (msymbols, &objfile->symbol_obstack); | |
846 | } | |
847 | } | |
848 | } | |
849 | ||
850 | /* Sort all the minimal symbols in OBJFILE. */ | |
851 | ||
852 | void | |
853 | msymbols_sort (objfile) | |
854 | struct objfile *objfile; | |
855 | { | |
856 | qsort (objfile->msymbols, objfile->minimal_symbol_count, | |
857 | sizeof (struct minimal_symbol), compare_minimal_symbols); | |
858 | } | |
859 | ||
860 | /* Check if PC is in a shared library trampoline code stub. | |
861 | Return minimal symbol for the trampoline entry or NULL if PC is not | |
862 | in a trampoline code stub. */ | |
863 | ||
864 | struct minimal_symbol * | |
865 | lookup_solib_trampoline_symbol_by_pc (pc) | |
866 | CORE_ADDR pc; | |
867 | { | |
868 | struct minimal_symbol *msymbol = lookup_minimal_symbol_by_pc (pc); | |
869 | ||
870 | if (msymbol != NULL && MSYMBOL_TYPE (msymbol) == mst_solib_trampoline) | |
871 | return msymbol; | |
872 | return NULL; | |
873 | } | |
874 | ||
875 | /* If PC is in a shared library trampoline code stub, return the | |
876 | address of the `real' function belonging to the stub. | |
877 | Return 0 if PC is not in a trampoline code stub or if the real | |
878 | function is not found in the minimal symbol table. | |
879 | ||
880 | We may fail to find the right function if a function with the | |
881 | same name is defined in more than one shared library, but this | |
882 | is considered bad programming style. We could return 0 if we find | |
883 | a duplicate function in case this matters someday. */ | |
884 | ||
885 | CORE_ADDR | |
886 | find_solib_trampoline_target (pc) | |
887 | CORE_ADDR pc; | |
888 | { | |
889 | struct objfile *objfile; | |
890 | struct minimal_symbol *msymbol; | |
891 | struct minimal_symbol *tsymbol = lookup_solib_trampoline_symbol_by_pc (pc); | |
892 | ||
893 | if (tsymbol != NULL) | |
894 | { | |
895 | ALL_MSYMBOLS (objfile, msymbol) | |
896 | { | |
897 | if (MSYMBOL_TYPE (msymbol) == mst_text | |
898 | && STREQ (SYMBOL_NAME (msymbol), SYMBOL_NAME (tsymbol))) | |
899 | return SYMBOL_VALUE_ADDRESS (msymbol); | |
900 | } | |
901 | } | |
902 | return 0; | |
903 | } | |
904 |