bfd/
[deliverable/binutils-gdb.git] / ld / ldcref.c
1 /* ldcref.c -- output a cross reference table
2 Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2006,
3 2007 Free Software Foundation, Inc.
4 Written by Ian Lance Taylor <ian@cygnus.com>
5
6 This file is part of GLD, the Gnu Linker.
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */
21
22 /* This file holds routines that manage the cross reference table.
23 The table is used to generate cross reference reports. It is also
24 used to implement the NOCROSSREFS command in the linker script. */
25
26 #include "sysdep.h"
27 #include "bfd.h"
28 #include "bfdlink.h"
29 #include "libiberty.h"
30 #include "demangle.h"
31 #include "objalloc.h"
32
33 #include "ld.h"
34 #include "ldmain.h"
35 #include "ldmisc.h"
36 #include "ldexp.h"
37 #include "ldlang.h"
38
39 /* We keep an instance of this structure for each reference to a
40 symbol from a given object. */
41
42 struct cref_ref {
43 /* The next reference. */
44 struct cref_ref *next;
45 /* The object. */
46 bfd *abfd;
47 /* True if the symbol is defined. */
48 unsigned int def : 1;
49 /* True if the symbol is common. */
50 unsigned int common : 1;
51 /* True if the symbol is undefined. */
52 unsigned int undef : 1;
53 };
54
55 /* We keep a hash table of symbols. Each entry looks like this. */
56
57 struct cref_hash_entry {
58 struct bfd_hash_entry root;
59 /* The demangled name. */
60 char *demangled;
61 /* References to and definitions of this symbol. */
62 struct cref_ref *refs;
63 };
64
65 /* This is what the hash table looks like. */
66
67 struct cref_hash_table {
68 struct bfd_hash_table root;
69 };
70
71 /* Forward declarations. */
72
73 static void output_one_cref (FILE *, struct cref_hash_entry *);
74 static void check_local_sym_xref (lang_input_statement_type *);
75 static bfd_boolean check_nocrossref (struct cref_hash_entry *, void *);
76 static void check_refs (const char *, bfd_boolean, asection *, bfd *,
77 struct lang_nocrossrefs *);
78 static void check_reloc_refs (bfd *, asection *, void *);
79
80 /* Look up an entry in the cref hash table. */
81
82 #define cref_hash_lookup(table, string, create, copy) \
83 ((struct cref_hash_entry *) \
84 bfd_hash_lookup (&(table)->root, (string), (create), (copy)))
85
86 /* Traverse the cref hash table. */
87
88 #define cref_hash_traverse(table, func, info) \
89 (bfd_hash_traverse \
90 (&(table)->root, \
91 (bfd_boolean (*) (struct bfd_hash_entry *, void *)) (func), \
92 (info)))
93
94 /* The cref hash table. */
95
96 static struct cref_hash_table cref_table;
97
98 /* Whether the cref hash table has been initialized. */
99
100 static bfd_boolean cref_initialized;
101
102 /* The number of symbols seen so far. */
103
104 static size_t cref_symcount;
105
106 /* Used to take a snapshot of the cref hash table when starting to
107 add syms from an as-needed library. */
108 static struct bfd_hash_entry **old_table;
109 static unsigned int old_size;
110 static unsigned int old_count;
111 static void *old_tab;
112 static void *alloc_mark;
113 static size_t tabsize, entsize, refsize;
114 static size_t old_symcount;
115
116 /* Create an entry in a cref hash table. */
117
118 static struct bfd_hash_entry *
119 cref_hash_newfunc (struct bfd_hash_entry *entry,
120 struct bfd_hash_table *table,
121 const char *string)
122 {
123 struct cref_hash_entry *ret = (struct cref_hash_entry *) entry;
124
125 /* Allocate the structure if it has not already been allocated by a
126 subclass. */
127 if (ret == NULL)
128 ret = ((struct cref_hash_entry *)
129 bfd_hash_allocate (table, sizeof (struct cref_hash_entry)));
130 if (ret == NULL)
131 return NULL;
132
133 /* Call the allocation method of the superclass. */
134 ret = ((struct cref_hash_entry *)
135 bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));
136 if (ret != NULL)
137 {
138 /* Set local fields. */
139 ret->demangled = NULL;
140 ret->refs = NULL;
141
142 /* Keep a count of the number of entries created in the hash
143 table. */
144 ++cref_symcount;
145 }
146
147 return &ret->root;
148 }
149
150 /* Add a symbol to the cref hash table. This is called for every
151 global symbol that is seen during the link. */
152
153 void
154 add_cref (const char *name,
155 bfd *abfd,
156 asection *section,
157 bfd_vma value ATTRIBUTE_UNUSED)
158 {
159 struct cref_hash_entry *h;
160 struct cref_ref *r;
161
162 if (! cref_initialized)
163 {
164 if (!bfd_hash_table_init (&cref_table.root, cref_hash_newfunc,
165 sizeof (struct cref_hash_entry)))
166 einfo (_("%X%P: bfd_hash_table_init of cref table failed: %E\n"));
167 cref_initialized = TRUE;
168 }
169
170 h = cref_hash_lookup (&cref_table, name, TRUE, FALSE);
171 if (h == NULL)
172 einfo (_("%X%P: cref_hash_lookup failed: %E\n"));
173
174 for (r = h->refs; r != NULL; r = r->next)
175 if (r->abfd == abfd)
176 break;
177
178 if (r == NULL)
179 {
180 r = bfd_hash_allocate (&cref_table.root, sizeof *r);
181 if (r == NULL)
182 einfo (_("%X%P: cref alloc failed: %E\n"));
183 r->next = h->refs;
184 h->refs = r;
185 r->abfd = abfd;
186 r->def = FALSE;
187 r->common = FALSE;
188 r->undef = FALSE;
189 }
190
191 if (bfd_is_und_section (section))
192 r->undef = TRUE;
193 else if (bfd_is_com_section (section))
194 r->common = TRUE;
195 else
196 r->def = TRUE;
197 }
198
199 /* Called before loading an as-needed library to take a snapshot of
200 the cref hash table, and after we have loaded or found that the
201 library was not needed. */
202
203 bfd_boolean
204 handle_asneeded_cref (bfd *abfd ATTRIBUTE_UNUSED,
205 enum notice_asneeded_action act)
206 {
207 unsigned int i;
208
209 if (!cref_initialized)
210 return TRUE;
211
212 if (act == notice_as_needed)
213 {
214 char *old_ent, *old_ref;
215
216 for (i = 0; i < cref_table.root.size; i++)
217 {
218 struct bfd_hash_entry *p;
219 struct cref_hash_entry *c;
220 struct cref_ref *r;
221
222 for (p = cref_table.root.table[i]; p != NULL; p = p->next)
223 {
224 entsize += cref_table.root.entsize;
225 c = (struct cref_hash_entry *) p;
226 for (r = c->refs; r != NULL; r = r->next)
227 refsize += sizeof (struct cref_hash_entry);
228 }
229 }
230
231 tabsize = cref_table.root.size * sizeof (struct bfd_hash_entry *);
232 old_tab = xmalloc (tabsize + entsize + refsize);
233
234 alloc_mark = bfd_hash_allocate (&cref_table.root, 1);
235 if (alloc_mark == NULL)
236 return FALSE;
237
238 memcpy (old_tab, cref_table.root.table, tabsize);
239 old_ent = (char *) old_tab + tabsize;
240 old_ref = (char *) old_ent + entsize;
241 old_table = cref_table.root.table;
242 old_size = cref_table.root.size;
243 old_count = cref_table.root.count;
244 old_symcount = cref_symcount;
245
246 for (i = 0; i < cref_table.root.size; i++)
247 {
248 struct bfd_hash_entry *p;
249 struct cref_hash_entry *c;
250 struct cref_ref *r;
251
252 for (p = cref_table.root.table[i]; p != NULL; p = p->next)
253 {
254 memcpy (old_ent, p, cref_table.root.entsize);
255 old_ent = (char *) old_ent + cref_table.root.entsize;
256 c = (struct cref_hash_entry *) p;
257 for (r = c->refs; r != NULL; r = r->next)
258 {
259 memcpy (old_ref, r, sizeof (struct cref_hash_entry));
260 old_ref = (char *) old_ref + sizeof (struct cref_hash_entry);
261 }
262 }
263 }
264 return TRUE;
265 }
266
267 if (act == notice_not_needed)
268 {
269 char *old_ent, *old_ref;
270
271 if (old_tab == NULL)
272 {
273 /* The only way old_tab can be NULL is if the cref hash table
274 had not been initialised when notice_as_needed. */
275 bfd_hash_table_free (&cref_table.root);
276 cref_initialized = FALSE;
277 return TRUE;
278 }
279
280 old_ent = (char *) old_tab + tabsize;
281 old_ref = (char *) old_ent + entsize;
282 cref_table.root.table = old_table;
283 cref_table.root.size = old_size;
284 cref_table.root.count = old_count;
285 memcpy (cref_table.root.table, old_tab, tabsize);
286 cref_symcount = old_symcount;
287
288 for (i = 0; i < cref_table.root.size; i++)
289 {
290 struct bfd_hash_entry *p;
291 struct cref_hash_entry *c;
292 struct cref_ref *r;
293
294 for (p = cref_table.root.table[i]; p != NULL; p = p->next)
295 {
296 memcpy (p, old_ent, cref_table.root.entsize);
297 old_ent = (char *) old_ent + cref_table.root.entsize;
298 c = (struct cref_hash_entry *) p;
299 for (r = c->refs; r != NULL; r = r->next)
300 {
301 memcpy (r, old_ref, sizeof (struct cref_hash_entry));
302 old_ref = (char *) old_ref + sizeof (struct cref_hash_entry);
303 }
304 }
305 }
306
307 objalloc_free_block ((struct objalloc *) cref_table.root.memory,
308 alloc_mark);
309 }
310 else if (act != notice_needed)
311 return FALSE;
312
313 free (old_tab);
314 old_tab = NULL;
315 return TRUE;
316 }
317
318 /* Copy the addresses of the hash table entries into an array. This
319 is called via cref_hash_traverse. We also fill in the demangled
320 name. */
321
322 static bfd_boolean
323 cref_fill_array (struct cref_hash_entry *h, void *data)
324 {
325 struct cref_hash_entry ***pph = data;
326
327 ASSERT (h->demangled == NULL);
328 h->demangled = bfd_demangle (output_bfd, h->root.string,
329 DMGL_ANSI | DMGL_PARAMS);
330
331 **pph = h;
332
333 ++*pph;
334
335 return TRUE;
336 }
337
338 /* Sort an array of cref hash table entries by name. */
339
340 static int
341 cref_sort_array (const void *a1, const void *a2)
342 {
343 const struct cref_hash_entry * const *p1 = a1;
344 const struct cref_hash_entry * const *p2 = a2;
345
346 return strcmp ((*p1)->demangled, (*p2)->demangled);
347 }
348
349 /* Write out the cref table. */
350
351 #define FILECOL (50)
352
353 void
354 output_cref (FILE *fp)
355 {
356 int len;
357 struct cref_hash_entry **csyms, **csym_fill, **csym, **csym_end;
358 const char *msg;
359
360 fprintf (fp, _("\nCross Reference Table\n\n"));
361 msg = _("Symbol");
362 fprintf (fp, "%s", msg);
363 len = strlen (msg);
364 while (len < FILECOL)
365 {
366 putc (' ', fp);
367 ++len;
368 }
369 fprintf (fp, _("File\n"));
370
371 if (! cref_initialized)
372 {
373 fprintf (fp, _("No symbols\n"));
374 return;
375 }
376
377 csyms = xmalloc (cref_symcount * sizeof (*csyms));
378
379 csym_fill = csyms;
380 cref_hash_traverse (&cref_table, cref_fill_array, &csym_fill);
381 ASSERT ((size_t) (csym_fill - csyms) == cref_symcount);
382
383 qsort (csyms, cref_symcount, sizeof (*csyms), cref_sort_array);
384
385 csym_end = csyms + cref_symcount;
386 for (csym = csyms; csym < csym_end; csym++)
387 output_one_cref (fp, *csym);
388 }
389
390 /* Output one entry in the cross reference table. */
391
392 static void
393 output_one_cref (FILE *fp, struct cref_hash_entry *h)
394 {
395 int len;
396 struct bfd_link_hash_entry *hl;
397 struct cref_ref *r;
398
399 hl = bfd_link_hash_lookup (link_info.hash, h->root.string, FALSE,
400 FALSE, TRUE);
401 if (hl == NULL)
402 einfo ("%P: symbol `%T' missing from main hash table\n",
403 h->root.string);
404 else
405 {
406 /* If this symbol is defined in a dynamic object but never
407 referenced by a normal object, then don't print it. */
408 if (hl->type == bfd_link_hash_defined)
409 {
410 if (hl->u.def.section->output_section == NULL)
411 return;
412 if (hl->u.def.section->owner != NULL
413 && (hl->u.def.section->owner->flags & DYNAMIC) != 0)
414 {
415 for (r = h->refs; r != NULL; r = r->next)
416 if ((r->abfd->flags & DYNAMIC) == 0)
417 break;
418 if (r == NULL)
419 return;
420 }
421 }
422 }
423
424 fprintf (fp, "%s ", h->demangled);
425 len = strlen (h->demangled) + 1;
426
427 for (r = h->refs; r != NULL; r = r->next)
428 {
429 if (r->def)
430 {
431 while (len < FILECOL)
432 {
433 putc (' ', fp);
434 ++len;
435 }
436 lfinfo (fp, "%B\n", r->abfd);
437 len = 0;
438 }
439 }
440
441 for (r = h->refs; r != NULL; r = r->next)
442 {
443 if (! r->def)
444 {
445 while (len < FILECOL)
446 {
447 putc (' ', fp);
448 ++len;
449 }
450 lfinfo (fp, "%B\n", r->abfd);
451 len = 0;
452 }
453 }
454
455 ASSERT (len == 0);
456 }
457
458 /* Check for prohibited cross references. */
459
460 void
461 check_nocrossrefs (void)
462 {
463 if (! cref_initialized)
464 return;
465
466 cref_hash_traverse (&cref_table, check_nocrossref, NULL);
467
468 lang_for_each_file (check_local_sym_xref);
469 }
470
471 /* Check for prohibited cross references to local and section symbols. */
472
473 static void
474 check_local_sym_xref (lang_input_statement_type *statement)
475 {
476 bfd *abfd;
477 lang_input_statement_type *li;
478 asymbol **asymbols, **syms;
479
480 abfd = statement->the_bfd;
481 if (abfd == NULL)
482 return;
483
484 li = abfd->usrdata;
485 if (li != NULL && li->asymbols != NULL)
486 asymbols = li->asymbols;
487 else
488 {
489 long symsize;
490 long symbol_count;
491
492 symsize = bfd_get_symtab_upper_bound (abfd);
493 if (symsize < 0)
494 einfo (_("%B%F: could not read symbols; %E\n"), abfd);
495 asymbols = xmalloc (symsize);
496 symbol_count = bfd_canonicalize_symtab (abfd, asymbols);
497 if (symbol_count < 0)
498 einfo (_("%B%F: could not read symbols: %E\n"), abfd);
499 if (li != NULL)
500 {
501 li->asymbols = asymbols;
502 li->symbol_count = symbol_count;
503 }
504 }
505
506 for (syms = asymbols; *syms; ++syms)
507 {
508 asymbol *sym = *syms;
509 if (sym->flags & (BSF_GLOBAL | BSF_WARNING | BSF_INDIRECT | BSF_FILE))
510 continue;
511 if ((sym->flags & (BSF_LOCAL | BSF_SECTION_SYM)) != 0
512 && sym->section->output_section != NULL)
513 {
514 const char *outsecname, *symname;
515 struct lang_nocrossrefs *ncrs;
516 struct lang_nocrossref *ncr;
517
518 outsecname = sym->section->output_section->name;
519 symname = NULL;
520 if ((sym->flags & BSF_SECTION_SYM) == 0)
521 symname = sym->name;
522 for (ncrs = nocrossref_list; ncrs != NULL; ncrs = ncrs->next)
523 for (ncr = ncrs->list; ncr != NULL; ncr = ncr->next)
524 if (strcmp (ncr->name, outsecname) == 0)
525 check_refs (symname, FALSE, sym->section, abfd, ncrs);
526 }
527 }
528
529 if (li == NULL)
530 free (asymbols);
531 }
532
533 /* Check one symbol to see if it is a prohibited cross reference. */
534
535 static bfd_boolean
536 check_nocrossref (struct cref_hash_entry *h, void *ignore ATTRIBUTE_UNUSED)
537 {
538 struct bfd_link_hash_entry *hl;
539 asection *defsec;
540 const char *defsecname;
541 struct lang_nocrossrefs *ncrs;
542 struct lang_nocrossref *ncr;
543 struct cref_ref *ref;
544
545 hl = bfd_link_hash_lookup (link_info.hash, h->root.string, FALSE,
546 FALSE, TRUE);
547 if (hl == NULL)
548 {
549 einfo (_("%P: symbol `%T' missing from main hash table\n"),
550 h->root.string);
551 return TRUE;
552 }
553
554 if (hl->type != bfd_link_hash_defined
555 && hl->type != bfd_link_hash_defweak)
556 return TRUE;
557
558 defsec = hl->u.def.section->output_section;
559 if (defsec == NULL)
560 return TRUE;
561 defsecname = bfd_get_section_name (defsec->owner, defsec);
562
563 for (ncrs = nocrossref_list; ncrs != NULL; ncrs = ncrs->next)
564 for (ncr = ncrs->list; ncr != NULL; ncr = ncr->next)
565 if (strcmp (ncr->name, defsecname) == 0)
566 for (ref = h->refs; ref != NULL; ref = ref->next)
567 check_refs (hl->root.string, TRUE, hl->u.def.section,
568 ref->abfd, ncrs);
569
570 return TRUE;
571 }
572
573 /* The struct is used to pass information from check_refs to
574 check_reloc_refs through bfd_map_over_sections. */
575
576 struct check_refs_info {
577 const char *sym_name;
578 asection *defsec;
579 struct lang_nocrossrefs *ncrs;
580 asymbol **asymbols;
581 bfd_boolean global;
582 };
583
584 /* This function is called for each symbol defined in a section which
585 prohibits cross references. We need to look through all references
586 to this symbol, and ensure that the references are not from
587 prohibited sections. */
588
589 static void
590 check_refs (const char *name,
591 bfd_boolean global,
592 asection *sec,
593 bfd *abfd,
594 struct lang_nocrossrefs *ncrs)
595 {
596 lang_input_statement_type *li;
597 asymbol **asymbols;
598 struct check_refs_info info;
599
600 /* We need to look through the relocations for this BFD, to see
601 if any of the relocations which refer to this symbol are from
602 a prohibited section. Note that we need to do this even for
603 the BFD in which the symbol is defined, since even a single
604 BFD might contain a prohibited cross reference. */
605
606 li = abfd->usrdata;
607 if (li != NULL && li->asymbols != NULL)
608 asymbols = li->asymbols;
609 else
610 {
611 long symsize;
612 long symbol_count;
613
614 symsize = bfd_get_symtab_upper_bound (abfd);
615 if (symsize < 0)
616 einfo (_("%B%F: could not read symbols; %E\n"), abfd);
617 asymbols = xmalloc (symsize);
618 symbol_count = bfd_canonicalize_symtab (abfd, asymbols);
619 if (symbol_count < 0)
620 einfo (_("%B%F: could not read symbols: %E\n"), abfd);
621 if (li != NULL)
622 {
623 li->asymbols = asymbols;
624 li->symbol_count = symbol_count;
625 }
626 }
627
628 info.sym_name = name;
629 info.global = global;
630 info.defsec = sec;
631 info.ncrs = ncrs;
632 info.asymbols = asymbols;
633 bfd_map_over_sections (abfd, check_reloc_refs, &info);
634
635 if (li == NULL)
636 free (asymbols);
637 }
638
639 /* This is called via bfd_map_over_sections. INFO->SYM_NAME is a symbol
640 defined in INFO->DEFSECNAME. If this section maps into any of the
641 sections listed in INFO->NCRS, other than INFO->DEFSECNAME, then we
642 look through the relocations. If any of the relocations are to
643 INFO->SYM_NAME, then we report a prohibited cross reference error. */
644
645 static void
646 check_reloc_refs (bfd *abfd, asection *sec, void *iarg)
647 {
648 struct check_refs_info *info = iarg;
649 asection *outsec;
650 const char *outsecname;
651 asection *outdefsec;
652 const char *outdefsecname;
653 struct lang_nocrossref *ncr;
654 const char *symname;
655 bfd_boolean global;
656 long relsize;
657 arelent **relpp;
658 long relcount;
659 arelent **p, **pend;
660
661 outsec = sec->output_section;
662 outsecname = bfd_get_section_name (outsec->owner, outsec);
663
664 outdefsec = info->defsec->output_section;
665 outdefsecname = bfd_get_section_name (outdefsec->owner, outdefsec);
666
667 /* The section where the symbol is defined is permitted. */
668 if (strcmp (outsecname, outdefsecname) == 0)
669 return;
670
671 for (ncr = info->ncrs->list; ncr != NULL; ncr = ncr->next)
672 if (strcmp (outsecname, ncr->name) == 0)
673 break;
674
675 if (ncr == NULL)
676 return;
677
678 /* This section is one for which cross references are prohibited.
679 Look through the relocations, and see if any of them are to
680 INFO->SYM_NAME. If INFO->SYMNAME is NULL, check for relocations
681 against the section symbol. If INFO->GLOBAL is TRUE, the
682 definition is global, check for relocations against the global
683 symbols. Otherwise check for relocations against the local and
684 section symbols. */
685
686 symname = info->sym_name;
687 global = info->global;
688
689 relsize = bfd_get_reloc_upper_bound (abfd, sec);
690 if (relsize < 0)
691 einfo (_("%B%F: could not read relocs: %E\n"), abfd);
692 if (relsize == 0)
693 return;
694
695 relpp = xmalloc (relsize);
696 relcount = bfd_canonicalize_reloc (abfd, sec, relpp, info->asymbols);
697 if (relcount < 0)
698 einfo (_("%B%F: could not read relocs: %E\n"), abfd);
699
700 p = relpp;
701 pend = p + relcount;
702 for (; p < pend && *p != NULL; p++)
703 {
704 arelent *q = *p;
705
706 if (q->sym_ptr_ptr != NULL
707 && *q->sym_ptr_ptr != NULL
708 && ((global
709 && (bfd_is_und_section (bfd_get_section (*q->sym_ptr_ptr))
710 || bfd_is_com_section (bfd_get_section (*q->sym_ptr_ptr))
711 || ((*q->sym_ptr_ptr)->flags & (BSF_GLOBAL
712 | BSF_WEAK)) != 0))
713 || (!global
714 && ((*q->sym_ptr_ptr)->flags & (BSF_LOCAL
715 | BSF_SECTION_SYM)) != 0
716 && bfd_get_section (*q->sym_ptr_ptr) == info->defsec))
717 && (symname != NULL
718 ? strcmp (bfd_asymbol_name (*q->sym_ptr_ptr), symname) == 0
719 : ((*q->sym_ptr_ptr)->flags & BSF_SECTION_SYM) != 0))
720 {
721 /* We found a reloc for the symbol. The symbol is defined
722 in OUTSECNAME. This reloc is from a section which is
723 mapped into a section from which references to OUTSECNAME
724 are prohibited. We must report an error. */
725 einfo (_("%X%C: prohibited cross reference from %s to `%T' in %s\n"),
726 abfd, sec, q->address, outsecname,
727 bfd_asymbol_name (*q->sym_ptr_ptr), outdefsecname);
728 }
729 }
730
731 free (relpp);
732 }
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