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>
6 This file is part of GLD, the Gnu Linker.
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.
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.
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. */
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. */
29 #include "libiberty.h"
39 /* We keep an instance of this structure for each reference to a
40 symbol from a given object. */
43 /* The next reference. */
44 struct cref_ref *next;
47 /* True if the symbol is defined. */
49 /* True if the symbol is common. */
50 unsigned int common : 1;
51 /* True if the symbol is undefined. */
52 unsigned int undef : 1;
55 /* We keep a hash table of symbols. Each entry looks like this. */
57 struct cref_hash_entry {
58 struct bfd_hash_entry root;
59 /* The demangled name. */
61 /* References to and definitions of this symbol. */
62 struct cref_ref *refs;
65 /* This is what the hash table looks like. */
67 struct cref_hash_table {
68 struct bfd_hash_table root;
71 /* Forward declarations. */
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 *);
80 /* Look up an entry in the cref hash table. */
82 #define cref_hash_lookup(table, string, create, copy) \
83 ((struct cref_hash_entry *) \
84 bfd_hash_lookup (&(table)->root, (string), (create), (copy)))
86 /* Traverse the cref hash table. */
88 #define cref_hash_traverse(table, func, info) \
91 (bfd_boolean (*) (struct bfd_hash_entry *, void *)) (func), \
94 /* The cref hash table. */
96 static struct cref_hash_table cref_table;
98 /* Whether the cref hash table has been initialized. */
100 static bfd_boolean cref_initialized;
102 /* The number of symbols seen so far. */
104 static size_t cref_symcount;
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;
116 /* Create an entry in a cref hash table. */
118 static struct bfd_hash_entry *
119 cref_hash_newfunc (struct bfd_hash_entry *entry,
120 struct bfd_hash_table *table,
123 struct cref_hash_entry *ret = (struct cref_hash_entry *) entry;
125 /* Allocate the structure if it has not already been allocated by a
128 ret = ((struct cref_hash_entry *)
129 bfd_hash_allocate (table, sizeof (struct cref_hash_entry)));
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));
138 /* Set local fields. */
139 ret->demangled = NULL;
142 /* Keep a count of the number of entries created in the hash
150 /* Add a symbol to the cref hash table. This is called for every
151 global symbol that is seen during the link. */
154 add_cref (const char *name,
157 bfd_vma value ATTRIBUTE_UNUSED)
159 struct cref_hash_entry *h;
162 if (! cref_initialized)
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;
170 h = cref_hash_lookup (&cref_table, name, TRUE, FALSE);
172 einfo (_("%X%P: cref_hash_lookup failed: %E\n"));
174 for (r = h->refs; r != NULL; r = r->next)
180 r = bfd_hash_allocate (&cref_table.root, sizeof *r);
182 einfo (_("%X%P: cref alloc failed: %E\n"));
191 if (bfd_is_und_section (section))
193 else if (bfd_is_com_section (section))
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. */
204 handle_asneeded_cref (bfd *abfd ATTRIBUTE_UNUSED,
205 enum notice_asneeded_action act)
209 if (!cref_initialized)
212 if (act == notice_as_needed)
214 char *old_ent, *old_ref;
216 for (i = 0; i < cref_table.root.size; i++)
218 struct bfd_hash_entry *p;
219 struct cref_hash_entry *c;
222 for (p = cref_table.root.table[i]; p != NULL; p = p->next)
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);
231 tabsize = cref_table.root.size * sizeof (struct bfd_hash_entry *);
232 old_tab = xmalloc (tabsize + entsize + refsize);
234 alloc_mark = bfd_hash_allocate (&cref_table.root, 1);
235 if (alloc_mark == NULL)
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;
246 for (i = 0; i < cref_table.root.size; i++)
248 struct bfd_hash_entry *p;
249 struct cref_hash_entry *c;
252 for (p = cref_table.root.table[i]; p != NULL; p = p->next)
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)
259 memcpy (old_ref, r, sizeof (struct cref_hash_entry));
260 old_ref = (char *) old_ref + sizeof (struct cref_hash_entry);
267 if (act == notice_not_needed)
269 char *old_ent, *old_ref;
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;
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;
288 for (i = 0; i < cref_table.root.size; i++)
290 struct bfd_hash_entry *p;
291 struct cref_hash_entry *c;
294 for (p = cref_table.root.table[i]; p != NULL; p = p->next)
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)
301 memcpy (r, old_ref, sizeof (struct cref_hash_entry));
302 old_ref = (char *) old_ref + sizeof (struct cref_hash_entry);
307 objalloc_free_block ((struct objalloc *) cref_table.root.memory,
310 else if (act != notice_needed)
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
323 cref_fill_array (struct cref_hash_entry *h, void *data)
325 struct cref_hash_entry ***pph = data;
327 ASSERT (h->demangled == NULL);
328 h->demangled = bfd_demangle (output_bfd, h->root.string,
329 DMGL_ANSI | DMGL_PARAMS);
338 /* Sort an array of cref hash table entries by name. */
341 cref_sort_array (const void *a1, const void *a2)
343 const struct cref_hash_entry * const *p1 = a1;
344 const struct cref_hash_entry * const *p2 = a2;
346 return strcmp ((*p1)->demangled, (*p2)->demangled);
349 /* Write out the cref table. */
354 output_cref (FILE *fp)
357 struct cref_hash_entry **csyms, **csym_fill, **csym, **csym_end;
360 fprintf (fp, _("\nCross Reference Table\n\n"));
362 fprintf (fp, "%s", msg);
364 while (len < FILECOL)
369 fprintf (fp, _("File\n"));
371 if (! cref_initialized)
373 fprintf (fp, _("No symbols\n"));
377 csyms = xmalloc (cref_symcount * sizeof (*csyms));
380 cref_hash_traverse (&cref_table, cref_fill_array, &csym_fill);
381 ASSERT ((size_t) (csym_fill - csyms) == cref_symcount);
383 qsort (csyms, cref_symcount, sizeof (*csyms), cref_sort_array);
385 csym_end = csyms + cref_symcount;
386 for (csym = csyms; csym < csym_end; csym++)
387 output_one_cref (fp, *csym);
390 /* Output one entry in the cross reference table. */
393 output_one_cref (FILE *fp, struct cref_hash_entry *h)
396 struct bfd_link_hash_entry *hl;
399 hl = bfd_link_hash_lookup (link_info.hash, h->root.string, FALSE,
402 einfo ("%P: symbol `%T' missing from main hash table\n",
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)
410 if (hl->u.def.section->output_section == NULL)
412 if (hl->u.def.section->owner != NULL
413 && (hl->u.def.section->owner->flags & DYNAMIC) != 0)
415 for (r = h->refs; r != NULL; r = r->next)
416 if ((r->abfd->flags & DYNAMIC) == 0)
424 fprintf (fp, "%s ", h->demangled);
425 len = strlen (h->demangled) + 1;
427 for (r = h->refs; r != NULL; r = r->next)
431 while (len < FILECOL)
436 lfinfo (fp, "%B\n", r->abfd);
441 for (r = h->refs; r != NULL; r = r->next)
445 while (len < FILECOL)
450 lfinfo (fp, "%B\n", r->abfd);
458 /* Check for prohibited cross references. */
461 check_nocrossrefs (void)
463 if (! cref_initialized)
466 cref_hash_traverse (&cref_table, check_nocrossref, NULL);
468 lang_for_each_file (check_local_sym_xref);
471 /* Check for prohibited cross references to local and section symbols. */
474 check_local_sym_xref (lang_input_statement_type *statement)
477 lang_input_statement_type *li;
478 asymbol **asymbols, **syms;
480 abfd = statement->the_bfd;
485 if (li != NULL && li->asymbols != NULL)
486 asymbols = li->asymbols;
492 symsize = bfd_get_symtab_upper_bound (abfd);
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);
501 li->asymbols = asymbols;
502 li->symbol_count = symbol_count;
506 for (syms = asymbols; *syms; ++syms)
508 asymbol *sym = *syms;
509 if (sym->flags & (BSF_GLOBAL | BSF_WARNING | BSF_INDIRECT | BSF_FILE))
511 if ((sym->flags & (BSF_LOCAL | BSF_SECTION_SYM)) != 0
512 && sym->section->output_section != NULL)
514 const char *outsecname, *symname;
515 struct lang_nocrossrefs *ncrs;
516 struct lang_nocrossref *ncr;
518 outsecname = sym->section->output_section->name;
520 if ((sym->flags & BSF_SECTION_SYM) == 0)
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);
533 /* Check one symbol to see if it is a prohibited cross reference. */
536 check_nocrossref (struct cref_hash_entry *h, void *ignore ATTRIBUTE_UNUSED)
538 struct bfd_link_hash_entry *hl;
540 const char *defsecname;
541 struct lang_nocrossrefs *ncrs;
542 struct lang_nocrossref *ncr;
543 struct cref_ref *ref;
545 hl = bfd_link_hash_lookup (link_info.hash, h->root.string, FALSE,
549 einfo (_("%P: symbol `%T' missing from main hash table\n"),
554 if (hl->type != bfd_link_hash_defined
555 && hl->type != bfd_link_hash_defweak)
558 defsec = hl->u.def.section->output_section;
561 defsecname = bfd_get_section_name (defsec->owner, defsec);
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,
573 /* The struct is used to pass information from check_refs to
574 check_reloc_refs through bfd_map_over_sections. */
576 struct check_refs_info {
577 const char *sym_name;
579 struct lang_nocrossrefs *ncrs;
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. */
590 check_refs (const char *name,
594 struct lang_nocrossrefs *ncrs)
596 lang_input_statement_type *li;
598 struct check_refs_info info;
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. */
607 if (li != NULL && li->asymbols != NULL)
608 asymbols = li->asymbols;
614 symsize = bfd_get_symtab_upper_bound (abfd);
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);
623 li->asymbols = asymbols;
624 li->symbol_count = symbol_count;
628 info.sym_name = name;
629 info.global = global;
632 info.asymbols = asymbols;
633 bfd_map_over_sections (abfd, check_reloc_refs, &info);
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. */
646 check_reloc_refs (bfd *abfd, asection *sec, void *iarg)
648 struct check_refs_info *info = iarg;
650 const char *outsecname;
652 const char *outdefsecname;
653 struct lang_nocrossref *ncr;
661 outsec = sec->output_section;
662 outsecname = bfd_get_section_name (outsec->owner, outsec);
664 outdefsec = info->defsec->output_section;
665 outdefsecname = bfd_get_section_name (outdefsec->owner, outdefsec);
667 /* The section where the symbol is defined is permitted. */
668 if (strcmp (outsecname, outdefsecname) == 0)
671 for (ncr = info->ncrs->list; ncr != NULL; ncr = ncr->next)
672 if (strcmp (outsecname, ncr->name) == 0)
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
686 symname = info->sym_name;
687 global = info->global;
689 relsize = bfd_get_reloc_upper_bound (abfd, sec);
691 einfo (_("%B%F: could not read relocs: %E\n"), abfd);
695 relpp = xmalloc (relsize);
696 relcount = bfd_canonicalize_reloc (abfd, sec, relpp, info->asymbols);
698 einfo (_("%B%F: could not read relocs: %E\n"), abfd);
702 for (; p < pend && *p != NULL; p++)
706 if (q->sym_ptr_ptr != NULL
707 && *q->sym_ptr_ptr != NULL
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
714 && ((*q->sym_ptr_ptr)->flags & (BSF_LOCAL
715 | BSF_SECTION_SYM)) != 0
716 && bfd_get_section (*q->sym_ptr_ptr) == info->defsec))
718 ? strcmp (bfd_asymbol_name (*q->sym_ptr_ptr), symname) == 0
719 : ((*q->sym_ptr_ptr)->flags & BSF_SECTION_SYM) != 0))
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);