1 /* Plugin control for the GNU linker.
2 Copyright 2010, 2011 Free Software Foundation, Inc.
4 This file is part of the GNU Binutils.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
19 MA 02110-1301, USA. */
22 #include "libiberty.h"
33 #include "plugin-api.h"
35 #if !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)
39 /* The suffix to append to the name of the real (claimed) object file
40 when generating a dummy BFD to hold the IR symbols sent from the
42 #define IRONLY_SUFFIX ".ironly\004"
44 /* This is sizeof an array of chars, not sizeof a const char *. We
45 also have to avoid inadvertently counting the trailing NUL. */
46 #define IRONLY_SUFFIX_LEN (sizeof (IRONLY_SUFFIX) - 1)
48 /* Stores a single argument passed to a plugin. */
49 typedef struct plugin_arg
51 struct plugin_arg *next;
55 /* Holds all details of a single plugin. */
58 /* Next on the list of plugins, or NULL at end of chain. */
60 /* The argument string given to --plugin. */
62 /* The shared library handle returned by dlopen. */
64 /* The list of argument string given to --plugin-opt. */
66 /* Number of args in the list, for convenience. */
68 /* The plugin's event handlers. */
69 ld_plugin_claim_file_handler claim_file_handler;
70 ld_plugin_all_symbols_read_handler all_symbols_read_handler;
71 ld_plugin_cleanup_handler cleanup_handler;
72 /* TRUE if the cleanup handlers have been called. */
73 bfd_boolean cleanup_done;
76 /* The master list of all plugins. */
77 static plugin_t *plugins_list = NULL;
79 /* We keep a tail pointer for easy linking on the end. */
80 static plugin_t **plugins_tail_chain_ptr = &plugins_list;
82 /* The last plugin added to the list, for receiving args. */
83 static plugin_t *last_plugin = NULL;
85 /* The tail of the arg chain of the last plugin added to the list. */
86 static plugin_arg_t **last_plugin_args_tail_chain_ptr = NULL;
88 /* The plugin which is currently having a callback executed. */
89 static plugin_t *called_plugin = NULL;
91 /* Last plugin to cause an error, if any. */
92 static const char *error_plugin = NULL;
94 /* A hash table that records symbols referenced by non-IR files. Used
95 at get_symbols time to determine whether any prevailing defs from
96 IR files are referenced only from other IR files, so tthat we can
97 we can distinguish the LDPR_PREVAILING_DEF and LDPR_PREVAILING_DEF_IRONLY
98 cases when establishing symbol resolutions. */
99 static struct bfd_hash_table *non_ironly_hash = NULL;
101 /* Set at all symbols read time, to avoid recursively offering the plugin
102 its own newly-added input files and libs to claim. */
103 static bfd_boolean no_more_claiming = FALSE;
105 /* If the --allow-multiple-definition command-line option is active, we
106 have to disable it so that BFD always calls our hook, and simulate the
107 effect (when not resolving IR vs. real symbols) ourselves by ensuring
108 TRUE is returned from the hook. */
109 static bfd_boolean plugin_cached_allow_multiple_defs = FALSE;
111 /* List of tags to set in the constant leading part of the tv array. */
112 static const enum ld_plugin_tag tv_header_tags[] =
119 LDPT_REGISTER_CLAIM_FILE_HOOK,
120 LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK,
121 LDPT_REGISTER_CLEANUP_HOOK,
124 LDPT_RELEASE_INPUT_FILE,
127 LDPT_ADD_INPUT_LIBRARY,
128 LDPT_SET_EXTRA_LIBRARY_PATH
131 /* How many entries in the constant leading part of the tv array. */
132 static const size_t tv_header_size = ARRAY_SIZE (tv_header_tags);
134 #if !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)
136 #define RTLD_NOW 0 /* Dummy value. */
139 dlopen (const char *file, int mode ATTRIBUTE_UNUSED)
141 return LoadLibrary (file);
145 dlsym (void *handle, const char *name)
147 return GetProcAddress (handle, name);
151 dlclose (void *handle)
153 FreeLibrary (handle);
157 #endif /* !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H) */
159 /* Helper function for exiting with error status. */
161 set_plugin_error (const char *plugin)
163 error_plugin = plugin;
167 /* Test if an error occurred. */
169 plugin_error_p (void)
171 return error_plugin != NULL;
174 /* Return name of plugin which caused an error if any. */
176 plugin_error_plugin (void)
178 return error_plugin ? error_plugin : _("<no plugin>");
181 /* Handle -plugin arg: find and load plugin, or return error. */
183 plugin_opt_plugin (const char *plugin)
187 newplug = xmalloc (sizeof *newplug);
188 memset (newplug, 0, sizeof *newplug);
189 newplug->name = plugin;
190 newplug->dlhandle = dlopen (plugin, RTLD_NOW);
191 if (!newplug->dlhandle)
192 return set_plugin_error (plugin);
194 /* Chain on end, so when we run list it is in command-line order. */
195 *plugins_tail_chain_ptr = newplug;
196 plugins_tail_chain_ptr = &newplug->next;
198 /* Record it as current plugin for receiving args. */
199 last_plugin = newplug;
200 last_plugin_args_tail_chain_ptr = &newplug->args;
204 /* Accumulate option arguments for last-loaded plugin, or return
207 plugin_opt_plugin_arg (const char *arg)
209 plugin_arg_t *newarg;
212 return set_plugin_error (_("<no plugin>"));
214 newarg = xmalloc (sizeof *newarg);
218 /* Chain on end to preserve command-line order. */
219 *last_plugin_args_tail_chain_ptr = newarg;
220 last_plugin_args_tail_chain_ptr = &newarg->next;
221 last_plugin->n_args++;
225 /* Create a dummy BFD. */
227 plugin_get_ir_dummy_bfd (const char *name, bfd *srctemplate)
232 bfd_use_reserved_id = 1;
233 abfd = bfd_create (concat (name, IRONLY_SUFFIX, (const char *)NULL),
235 bfd_set_arch_info (abfd, bfd_get_arch_info (srctemplate));
236 bfd_make_writable (abfd);
237 bfd_copy_private_bfd_data (srctemplate, abfd);
238 bfd_set_gp_size (abfd, bfd_get_gp_size (abfd));
239 /* Create a minimal set of sections to own the symbols. */
240 sec = bfd_make_section_old_way (abfd, ".text");
241 bfd_set_section_flags (abfd, sec,
242 (SEC_CODE | SEC_HAS_CONTENTS | SEC_READONLY
243 | SEC_ALLOC | SEC_LOAD | SEC_KEEP));
244 sec->output_section = sec;
245 sec->output_offset = 0;
249 /* Check if the BFD passed in is an IR dummy object file. */
251 is_ir_dummy_bfd (const bfd *abfd)
257 namlen = strlen (abfd->filename);
258 if (namlen < IRONLY_SUFFIX_LEN)
260 return !strcmp (abfd->filename + namlen - IRONLY_SUFFIX_LEN, IRONLY_SUFFIX);
263 /* Helpers to convert between BFD and GOLD symbol formats. */
264 static enum ld_plugin_status
265 asymbol_from_plugin_symbol (bfd *abfd, asymbol *asym,
266 const struct ld_plugin_symbol *ldsym)
268 flagword flags = BSF_NO_FLAGS;
269 struct bfd_section *section;
271 asym->the_bfd = abfd;
272 asym->name = (ldsym->version
273 ? concat (ldsym->name, "@", ldsym->version, NULL)
283 section = bfd_get_section_by_name (abfd, ".text");
290 section = bfd_und_section_ptr;
295 section = bfd_com_section_ptr;
296 asym->value = ldsym->size;
297 /* For ELF targets, set alignment of common symbol to 1. */
298 if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
299 ((elf_symbol_type *) asym)->internal_elf_sym.st_value = 1;
306 asym->section = section;
308 /* Visibility only applies on ELF targets. */
309 if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
311 elf_symbol_type *elfsym = elf_symbol_from (abfd, asym);
312 unsigned char visibility;
315 einfo (_("%P%F: %s: non-ELF symbol in ELF BFD!\n"), asym->name);
316 switch (ldsym->visibility)
319 einfo (_("%P%F: unknown ELF symbol visibility: %d!\n"),
322 visibility = STV_DEFAULT;
325 visibility = STV_PROTECTED;
328 visibility = STV_INTERNAL;
331 visibility = STV_HIDDEN;
334 elfsym->internal_elf_sym.st_other
335 = (visibility | (elfsym->internal_elf_sym.st_other
336 & ~ELF_ST_VISIBILITY (-1)));
342 /* Register a claim-file handler. */
343 static enum ld_plugin_status
344 register_claim_file (ld_plugin_claim_file_handler handler)
346 ASSERT (called_plugin);
347 called_plugin->claim_file_handler = handler;
351 /* Register an all-symbols-read handler. */
352 static enum ld_plugin_status
353 register_all_symbols_read (ld_plugin_all_symbols_read_handler handler)
355 ASSERT (called_plugin);
356 called_plugin->all_symbols_read_handler = handler;
360 /* Register a cleanup handler. */
361 static enum ld_plugin_status
362 register_cleanup (ld_plugin_cleanup_handler handler)
364 ASSERT (called_plugin);
365 called_plugin->cleanup_handler = handler;
369 /* Add symbols from a plugin-claimed input file. */
370 static enum ld_plugin_status
371 add_symbols (void *handle, int nsyms, const struct ld_plugin_symbol *syms)
376 ASSERT (called_plugin);
377 symptrs = xmalloc (nsyms * sizeof *symptrs);
378 for (n = 0; n < nsyms; n++)
380 enum ld_plugin_status rv;
381 asymbol *bfdsym = bfd_make_empty_symbol (abfd);
383 rv = asymbol_from_plugin_symbol (abfd, bfdsym, syms + n);
387 bfd_set_symtab (abfd, symptrs, nsyms);
391 /* Get the input file information with an open (possibly re-opened)
393 static enum ld_plugin_status
394 get_input_file (const void *handle, struct ld_plugin_input_file *file)
396 ASSERT (called_plugin);
402 /* Release the input file. */
403 static enum ld_plugin_status
404 release_input_file (const void *handle)
406 ASSERT (called_plugin);
411 /* Return TRUE if a defined symbol might be reachable from outside the
412 universe of claimed objects. */
413 static inline bfd_boolean
414 is_visible_from_outside (struct ld_plugin_symbol *lsym, asection *section,
415 struct bfd_link_hash_entry *blhe)
417 /* Section's owner may be NULL if it is the absolute
418 section, fortunately is_ir_dummy_bfd handles that. */
419 if (!is_ir_dummy_bfd (section->owner))
421 if (link_info.relocatable)
423 if (link_info.export_dynamic || link_info.shared)
425 /* Only ELF symbols really have visibility. */
426 if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour)
428 struct elf_link_hash_entry *el = (struct elf_link_hash_entry *)blhe;
429 int vis = ELF_ST_VISIBILITY (el->other);
430 return vis == STV_DEFAULT || vis == STV_PROTECTED;
432 /* On non-ELF targets, we can safely make inferences by considering
433 what visibility the plugin would have liked to apply when it first
434 sent us the symbol. During ELF symbol processing, visibility only
435 ever becomes more restrictive, not less, when symbols are merged,
436 so this is a conservative estimate; it may give false positives,
437 declaring something visible from outside when it in fact would
438 not have been, but this will only lead to missed optimisation
439 opportunities during LTRANS at worst; it will not give false
440 negatives, which can lead to the disastrous conclusion that the
441 related symbol is IRONLY. (See GCC PR46319 for an example.) */
442 return (lsym->visibility == LDPV_DEFAULT
443 || lsym->visibility == LDPV_PROTECTED);
448 /* Get the symbol resolution info for a plugin-claimed input file. */
449 static enum ld_plugin_status
450 get_symbols (const void *handle, int nsyms, struct ld_plugin_symbol *syms)
452 const bfd *abfd = handle;
454 ASSERT (called_plugin);
455 for (n = 0; n < nsyms; n++)
457 struct bfd_link_hash_entry *blhe;
461 blhe = bfd_link_hash_lookup (link_info.hash, syms[n].name,
465 syms[n].resolution = LDPR_UNKNOWN;
469 /* Determine resolution from blhe type and symbol's original type. */
470 if (blhe->type == bfd_link_hash_undefined
471 || blhe->type == bfd_link_hash_undefweak)
473 syms[n].resolution = LDPR_UNDEF;
476 if (blhe->type != bfd_link_hash_defined
477 && blhe->type != bfd_link_hash_defweak
478 && blhe->type != bfd_link_hash_common)
480 /* We should not have a new, indirect or warning symbol here. */
481 einfo ("%P%F: %s: plugin symbol table corrupt (sym type %d)\n",
482 called_plugin->name, blhe->type);
485 /* Find out which section owns the symbol. Since it's not undef,
486 it must have an owner; if it's not a common symbol, both defs
487 and weakdefs keep it in the same place. */
488 owner_sec = (blhe->type == bfd_link_hash_common)
489 ? blhe->u.c.p->section
490 : blhe->u.def.section;
492 /* We need to know if the sym is referenced from non-IR files. Or
493 even potentially-referenced, perhaps in a future final link if
494 this is a partial one, perhaps dynamically at load-time if the
495 symbol is externally visible. */
496 ironly = (!is_visible_from_outside (&syms[n], owner_sec, blhe)
497 && !bfd_hash_lookup (non_ironly_hash, syms[n].name,
499 && strcmp (syms[n].name, entry_symbol.name) != 0);
501 /* If it was originally undefined or common, then it has been
502 resolved; determine how. */
503 if (syms[n].def == LDPK_UNDEF
504 || syms[n].def == LDPK_WEAKUNDEF
505 || syms[n].def == LDPK_COMMON)
507 if (owner_sec->owner == link_info.output_bfd)
508 syms[n].resolution = LDPR_RESOLVED_EXEC;
509 else if (owner_sec->owner == abfd)
510 syms[n].resolution = (ironly
511 ? LDPR_PREVAILING_DEF_IRONLY
512 : LDPR_PREVAILING_DEF);
513 else if (is_ir_dummy_bfd (owner_sec->owner))
514 syms[n].resolution = LDPR_RESOLVED_IR;
515 else if (owner_sec->owner != NULL
516 && (owner_sec->owner->flags & DYNAMIC) != 0)
517 syms[n].resolution = LDPR_RESOLVED_DYN;
519 syms[n].resolution = LDPR_RESOLVED_EXEC;
523 /* Was originally def, or weakdef. Does it prevail? If the
524 owner is the original dummy bfd that supplied it, then this
525 is the definition that has prevailed. */
526 if (owner_sec->owner == link_info.output_bfd)
527 syms[n].resolution = LDPR_PREEMPTED_REG;
528 else if (owner_sec->owner == abfd)
530 syms[n].resolution = (ironly
531 ? LDPR_PREVAILING_DEF_IRONLY
532 : LDPR_PREVAILING_DEF);
536 /* Was originally def, weakdef, or common, but has been pre-empted. */
537 syms[n].resolution = is_ir_dummy_bfd (owner_sec->owner)
539 : LDPR_PREEMPTED_REG;
544 /* Add a new (real) input file generated by a plugin. */
545 static enum ld_plugin_status
546 add_input_file (const char *pathname)
548 ASSERT (called_plugin);
549 if (!lang_add_input_file (xstrdup (pathname), lang_input_file_is_file_enum,
555 /* Add a new (real) library required by a plugin. */
556 static enum ld_plugin_status
557 add_input_library (const char *pathname)
559 ASSERT (called_plugin);
560 if (!lang_add_input_file (xstrdup (pathname), lang_input_file_is_l_enum,
566 /* Set the extra library path to be used by libraries added via
567 add_input_library. */
568 static enum ld_plugin_status
569 set_extra_library_path (const char *path)
571 ASSERT (called_plugin);
572 ldfile_add_library_path (xstrdup (path), FALSE);
576 /* Issue a diagnostic message from a plugin. */
577 static enum ld_plugin_status
578 message (int level, const char *format, ...)
581 va_start (args, format);
586 vfinfo (stdout, format, args, FALSE);
590 vfinfo (stdout, format, args, TRUE);
597 char *newfmt = ACONCAT ((level == LDPL_FATAL
598 ? "%P%F: " : "%P%X: ",
599 format, "\n", NULL));
601 vfinfo (stderr, newfmt, args, TRUE);
611 /* Helper to size leading part of tv array and set it up. */
613 set_tv_header (struct ld_plugin_tv *tv)
618 static const unsigned int major = (unsigned)(BFD_VERSION / 100000000UL);
619 static const unsigned int minor = (unsigned)(BFD_VERSION / 1000000UL) % 100;
622 return tv_header_size;
624 for (i = 0; i < tv_header_size; i++)
626 tv[i].tv_tag = tv_header_tags[i];
627 #define TVU(x) tv[i].tv_u.tv_ ## x
628 switch (tv[i].tv_tag)
631 TVU(message) = message;
633 case LDPT_API_VERSION:
634 TVU(val) = LD_PLUGIN_API_VERSION;
636 case LDPT_GNU_LD_VERSION:
637 TVU(val) = major * 100 + minor;
639 case LDPT_LINKER_OUTPUT:
640 TVU(val) = (link_info.relocatable
642 : (link_info.shared ? LDPO_DYN : LDPO_EXEC));
644 case LDPT_OUTPUT_NAME:
645 TVU(string) = output_filename;
647 case LDPT_REGISTER_CLAIM_FILE_HOOK:
648 TVU(register_claim_file) = register_claim_file;
650 case LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK:
651 TVU(register_all_symbols_read) = register_all_symbols_read;
653 case LDPT_REGISTER_CLEANUP_HOOK:
654 TVU(register_cleanup) = register_cleanup;
656 case LDPT_ADD_SYMBOLS:
657 TVU(add_symbols) = add_symbols;
659 case LDPT_GET_INPUT_FILE:
660 TVU(get_input_file) = get_input_file;
662 case LDPT_RELEASE_INPUT_FILE:
663 TVU(release_input_file) = release_input_file;
665 case LDPT_GET_SYMBOLS:
666 TVU(get_symbols) = get_symbols;
668 case LDPT_ADD_INPUT_FILE:
669 TVU(add_input_file) = add_input_file;
671 case LDPT_ADD_INPUT_LIBRARY:
672 TVU(add_input_library) = add_input_library;
674 case LDPT_SET_EXTRA_LIBRARY_PATH:
675 TVU(set_extra_library_path) = set_extra_library_path;
678 /* Added a new entry to the array without adding
679 a new case to set up its value is a bug. */
684 return tv_header_size;
687 /* Append the per-plugin args list and trailing LDPT_NULL to tv. */
689 set_tv_plugin_args (plugin_t *plugin, struct ld_plugin_tv *tv)
691 plugin_arg_t *arg = plugin->args;
694 tv->tv_tag = LDPT_OPTION;
695 tv->tv_u.tv_string = arg->arg;
699 tv->tv_tag = LDPT_NULL;
703 /* Return true if any plugins are active this run. Only valid
704 after options have been processed. */
706 plugin_active_plugins_p (void)
708 return plugins_list != NULL;
711 /* Load up and initialise all plugins after argument parsing. */
713 plugin_load_plugins (void)
715 struct ld_plugin_tv *my_tv;
716 unsigned int max_args = 0;
717 plugin_t *curplug = plugins_list;
719 /* If there are no plugins, we need do nothing this run. */
723 /* First pass over plugins to find max # args needed so that we
724 can size and allocate the tv array. */
727 if (curplug->n_args > max_args)
728 max_args = curplug->n_args;
729 curplug = curplug->next;
732 /* Allocate tv array and initialise constant part. */
733 my_tv = xmalloc ((max_args + 1 + tv_header_size) * sizeof *my_tv);
734 set_tv_header (my_tv);
736 /* Pass over plugins again, activating them. */
737 curplug = plugins_list;
740 enum ld_plugin_status rv;
741 ld_plugin_onload onloadfn = dlsym (curplug->dlhandle, "onload");
743 onloadfn = dlsym (curplug->dlhandle, "_onload");
745 return set_plugin_error (curplug->name);
746 set_tv_plugin_args (curplug, &my_tv[tv_header_size]);
747 called_plugin = curplug;
748 rv = (*onloadfn) (my_tv);
749 called_plugin = NULL;
751 return set_plugin_error (curplug->name);
752 curplug = curplug->next;
755 /* Since plugin(s) inited ok, assume they're going to want symbol
756 resolutions, which needs us to track which symbols are referenced
757 by non-IR files using the linker's notice callback. */
758 link_info.notice_all = TRUE;
763 /* Call 'claim file' hook for all plugins. */
765 plugin_call_claim_file (const struct ld_plugin_input_file *file, int *claimed)
767 plugin_t *curplug = plugins_list;
769 if (no_more_claiming)
771 while (curplug && !*claimed)
773 if (curplug->claim_file_handler)
775 enum ld_plugin_status rv;
776 called_plugin = curplug;
777 rv = (*curplug->claim_file_handler) (file, claimed);
778 called_plugin = NULL;
780 set_plugin_error (curplug->name);
782 curplug = curplug->next;
784 return plugin_error_p () ? -1 : 0;
787 /* Call 'all symbols read' hook for all plugins. */
789 plugin_call_all_symbols_read (void)
791 plugin_t *curplug = plugins_list;
793 /* Disable any further file-claiming. */
794 no_more_claiming = TRUE;
796 /* If --allow-multiple-definition is in effect, we need to disable it,
797 as the plugin infrastructure relies on the multiple_definition
798 callback to swap out the dummy IR-only BFDs for new real ones
799 when it starts opening the files added during this callback. */
800 plugin_cached_allow_multiple_defs = link_info.allow_multiple_definition;
801 link_info.allow_multiple_definition = FALSE;
805 if (curplug->all_symbols_read_handler)
807 enum ld_plugin_status rv;
808 called_plugin = curplug;
809 rv = (*curplug->all_symbols_read_handler) ();
810 called_plugin = NULL;
812 set_plugin_error (curplug->name);
814 curplug = curplug->next;
816 return plugin_error_p () ? -1 : 0;
819 /* Call 'cleanup' hook for all plugins at exit. */
821 plugin_call_cleanup (void)
823 plugin_t *curplug = plugins_list;
826 if (curplug->cleanup_handler && !curplug->cleanup_done)
828 enum ld_plugin_status rv;
829 curplug->cleanup_done = TRUE;
830 called_plugin = curplug;
831 rv = (*curplug->cleanup_handler) ();
832 called_plugin = NULL;
834 set_plugin_error (curplug->name);
835 dlclose (curplug->dlhandle);
837 curplug = curplug->next;
839 if (plugin_error_p ())
840 info_msg (_("%P: %s: error in plugin cleanup (ignored)\n"),
841 plugin_error_plugin ());
844 /* Lazily init the non_ironly hash table. */
846 init_non_ironly_hash (void)
848 if (non_ironly_hash == NULL)
851 (struct bfd_hash_table *) xmalloc (sizeof (struct bfd_hash_table));
852 if (!bfd_hash_table_init_n (non_ironly_hash,
854 sizeof (struct bfd_hash_entry),
856 einfo (_("%P%F: bfd_hash_table_init failed: %E\n"));
860 /* To determine which symbols should be resolved LDPR_PREVAILING_DEF
861 and which LDPR_PREVAILING_DEF_IRONLY, we notice all the symbols as
862 the linker adds them to the linker hash table. If we see a symbol
863 being referenced from a non-IR file, we add it to the non_ironly hash
864 table. If we can't find it there at get_symbols time, we know that
865 it was referenced only by IR files. We have to notice_all symbols,
866 because we won't necessarily know until later which ones will be
867 contributed by IR files. */
869 plugin_notice (struct bfd_link_info *info ATTRIBUTE_UNUSED,
870 const char *name, bfd *abfd,
871 asection *section, bfd_vma value ATTRIBUTE_UNUSED)
873 bfd_boolean is_ref = bfd_is_und_section (section);
874 bfd_boolean is_dummy = is_ir_dummy_bfd (abfd);
875 init_non_ironly_hash ();
876 /* We only care about refs, not defs, indicated by section pointing
877 to the undefined section (according to the bfd linker notice callback
878 interface definition). */
879 if (is_ref && !is_dummy)
881 /* This is a ref from a non-IR file, so note the ref'd symbol
882 in the non-IR-only hash. */
883 if (!bfd_hash_lookup (non_ironly_hash, name, TRUE, TRUE))
884 einfo (_("%P%X: %s: hash table failure adding symbol %s\n"),
885 abfd->filename, name);
887 else if (!is_ref && is_dummy)
889 /* No further processing since this is a def from an IR dummy BFD. */
893 /* Continue with cref/nocrossref/trace-sym processing. */
897 /* When we add new object files to the link at all symbols read time,
898 these contain the real code and symbols generated from the IR files,
899 and so duplicate all the definitions already supplied by the dummy
900 IR-only BFDs that we created at claim files time. We use the linker's
901 multiple-definitions callback hook to fix up the clash, discarding
902 the symbol from the IR-only BFD in favour of the symbol from the
903 real BFD. We return true if this was not-really-a-clash because
904 we've fixed it up, or anyway if --allow-multiple-definition was in
905 effect (before we disabled it to ensure we got called back). */
907 plugin_multiple_definition (struct bfd_link_info *info, const char *name,
908 bfd *obfd, asection *osec ATTRIBUTE_UNUSED,
909 bfd_vma oval ATTRIBUTE_UNUSED,
910 bfd *nbfd, asection *nsec, bfd_vma nval)
912 if (is_ir_dummy_bfd (obfd))
914 struct bfd_link_hash_entry *blhe
915 = bfd_link_hash_lookup (info->hash, name, FALSE, FALSE, FALSE);
917 einfo (_("%P%X: %s: can't find IR symbol '%s'\n"), nbfd->filename,
919 else if (blhe->type != bfd_link_hash_defined)
920 einfo (_("%P%x: %s: bad IR symbol type %d\n"), name, blhe->type);
921 /* Replace it with new details. */
922 blhe->u.def.section = nsec;
923 blhe->u.def.value = nval;
926 return plugin_cached_allow_multiple_defs;