2 Copyright 1995 Free Software Foundation, Inc.
4 This file is part of BFD, the Binary File Descriptor library.
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 2 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
20 /* ELF linker code. */
22 static boolean elf_link_add_object_symbols
23 PARAMS ((bfd *, struct bfd_link_info *));
24 static boolean elf_link_add_archive_symbols
25 PARAMS ((bfd *, struct bfd_link_info *));
26 static Elf_Internal_Rela *elf_link_read_relocs
27 PARAMS ((bfd *, asection *, PTR, Elf_Internal_Rela *, boolean));
28 static boolean elf_export_symbol
29 PARAMS ((struct elf_link_hash_entry *, PTR));
30 static boolean elf_adjust_dynamic_symbol
31 PARAMS ((struct elf_link_hash_entry *, PTR));
33 /* This struct is used to pass information to routines called via
34 elf_link_hash_traverse which must return failure. */
36 struct elf_info_failed
39 struct bfd_link_info *info;
42 /* Given an ELF BFD, add symbols to the global hash table as
46 elf_bfd_link_add_symbols (abfd, info)
48 struct bfd_link_info *info;
50 switch (bfd_get_format (abfd))
53 return elf_link_add_object_symbols (abfd, info);
55 return elf_link_add_archive_symbols (abfd, info);
57 bfd_set_error (bfd_error_wrong_format);
62 /* Add symbols from an ELF archive file to the linker hash table. We
63 don't use _bfd_generic_link_add_archive_symbols because of a
64 problem which arises on UnixWare. The UnixWare libc.so is an
65 archive which includes an entry libc.so.1 which defines a bunch of
66 symbols. The libc.so archive also includes a number of other
67 object files, which also define symbols, some of which are the same
68 as those defined in libc.so.1. Correct linking requires that we
69 consider each object file in turn, and include it if it defines any
70 symbols we need. _bfd_generic_link_add_archive_symbols does not do
71 this; it looks through the list of undefined symbols, and includes
72 any object file which defines them. When this algorithm is used on
73 UnixWare, it winds up pulling in libc.so.1 early and defining a
74 bunch of symbols. This means that some of the other objects in the
75 archive are not included in the link, which is incorrect since they
76 precede libc.so.1 in the archive.
78 Fortunately, ELF archive handling is simpler than that done by
79 _bfd_generic_link_add_archive_symbols, which has to allow for a.out
80 oddities. In ELF, if we find a symbol in the archive map, and the
81 symbol is currently undefined, we know that we must pull in that
84 Unfortunately, we do have to make multiple passes over the symbol
85 table until nothing further is resolved. */
88 elf_link_add_archive_symbols (abfd, info)
90 struct bfd_link_info *info;
93 boolean *defined = NULL;
94 boolean *included = NULL;
98 if (! bfd_has_map (abfd))
100 /* An empty archive is a special case. */
101 if (bfd_openr_next_archived_file (abfd, (bfd *) NULL) == NULL)
103 bfd_set_error (bfd_error_no_armap);
107 /* Keep track of all symbols we know to be already defined, and all
108 files we know to be already included. This is to speed up the
109 second and subsequent passes. */
110 c = bfd_ardata (abfd)->symdef_count;
113 defined = (boolean *) malloc (c * sizeof (boolean));
114 included = (boolean *) malloc (c * sizeof (boolean));
115 if (defined == (boolean *) NULL || included == (boolean *) NULL)
117 bfd_set_error (bfd_error_no_memory);
120 memset (defined, 0, c * sizeof (boolean));
121 memset (included, 0, c * sizeof (boolean));
123 symdefs = bfd_ardata (abfd)->symdefs;
136 symdefend = symdef + c;
137 for (i = 0; symdef < symdefend; symdef++, i++)
139 struct elf_link_hash_entry *h;
141 struct bfd_link_hash_entry *undefs_tail;
144 if (defined[i] || included[i])
146 if (symdef->file_offset == last)
152 h = elf_link_hash_lookup (elf_hash_table (info), symdef->name,
153 false, false, false);
154 if (h == (struct elf_link_hash_entry *) NULL)
156 if (h->root.type != bfd_link_hash_undefined)
158 if (h->root.type != bfd_link_hash_undefweak)
163 /* We need to include this archive member. */
165 element = _bfd_get_elt_at_filepos (abfd, symdef->file_offset);
166 if (element == (bfd *) NULL)
169 if (! bfd_check_format (element, bfd_object))
172 /* Doublecheck that we have not included this object
173 already--it should be impossible, but there may be
174 something wrong with the archive. */
175 if (element->archive_pass != 0)
177 bfd_set_error (bfd_error_bad_value);
180 element->archive_pass = 1;
182 undefs_tail = info->hash->undefs_tail;
184 if (! (*info->callbacks->add_archive_element) (info, element,
187 if (! elf_link_add_object_symbols (element, info))
190 /* If there are any new undefined symbols, we need to make
191 another pass through the archive in order to see whether
192 they can be defined. FIXME: This isn't perfect, because
193 common symbols wind up on undefs_tail and because an
194 undefined symbol which is defined later on in this pass
195 does not require another pass. This isn't a bug, but it
196 does make the code less efficient than it could be. */
197 if (undefs_tail != info->hash->undefs_tail)
200 /* Look backward to mark all symbols from this object file
201 which we have already seen in this pass. */
205 included[mark] = true;
210 while (symdefs[mark].file_offset == symdef->file_offset);
212 /* We mark subsequent symbols from this object file as we go
213 on through the loop. */
214 last = symdef->file_offset;
225 if (defined != (boolean *) NULL)
227 if (included != (boolean *) NULL)
232 /* Add symbols from an ELF object file to the linker hash table. */
235 elf_link_add_object_symbols (abfd, info)
237 struct bfd_link_info *info;
239 boolean (*add_symbol_hook) PARAMS ((bfd *, struct bfd_link_info *,
240 const Elf_Internal_Sym *,
241 const char **, flagword *,
242 asection **, bfd_vma *));
243 boolean (*check_relocs) PARAMS ((bfd *, struct bfd_link_info *,
244 asection *, const Elf_Internal_Rela *));
246 Elf_Internal_Shdr *hdr;
250 Elf_External_Sym *buf = NULL;
251 struct elf_link_hash_entry **sym_hash;
253 Elf_External_Dyn *dynbuf = NULL;
254 struct elf_link_hash_entry *weaks;
255 Elf_External_Sym *esym;
256 Elf_External_Sym *esymend;
258 add_symbol_hook = get_elf_backend_data (abfd)->elf_add_symbol_hook;
259 collect = get_elf_backend_data (abfd)->collect;
261 /* As a GNU extension, any input sections which are named
262 .gnu.warning.SYMBOL are treated as warning symbols for the given
263 symbol. This differs from .gnu.warning sections, which generate
264 warnings when they are included in an output file. */
269 for (s = abfd->sections; s != NULL; s = s->next)
273 name = bfd_get_section_name (abfd, s);
274 if (strncmp (name, ".gnu.warning.", sizeof ".gnu.warning." - 1) == 0)
279 sz = bfd_section_size (abfd, s);
280 msg = (char *) bfd_alloc (abfd, sz);
283 bfd_set_error (bfd_error_no_memory);
287 if (! bfd_get_section_contents (abfd, s, msg, (file_ptr) 0, sz))
290 if (! (_bfd_generic_link_add_one_symbol
292 name + sizeof ".gnu.warning." - 1,
293 BSF_WARNING, s, (bfd_vma) 0, msg, false, collect,
294 (struct bfd_link_hash_entry **) NULL)))
297 if (! info->relocateable)
299 /* Clobber the section size so that the warning does
300 not get copied into the output file. */
307 /* A stripped shared library might only have a dynamic symbol table,
308 not a regular symbol table. In that case we can still go ahead
309 and link using the dynamic symbol table. */
310 if (elf_onesymtab (abfd) == 0
311 && elf_dynsymtab (abfd) != 0)
313 elf_onesymtab (abfd) = elf_dynsymtab (abfd);
314 elf_tdata (abfd)->symtab_hdr = elf_tdata (abfd)->dynsymtab_hdr;
317 hdr = &elf_tdata (abfd)->symtab_hdr;
318 symcount = hdr->sh_size / sizeof (Elf_External_Sym);
320 /* The sh_info field of the symtab header tells us where the
321 external symbols start. We don't care about the local symbols at
323 if (elf_bad_symtab (abfd))
325 extsymcount = symcount;
330 extsymcount = symcount - hdr->sh_info;
331 extsymoff = hdr->sh_info;
334 buf = (Elf_External_Sym *) malloc (extsymcount * sizeof (Elf_External_Sym));
335 if (buf == NULL && extsymcount != 0)
337 bfd_set_error (bfd_error_no_memory);
341 /* We store a pointer to the hash table entry for each external
343 sym_hash = ((struct elf_link_hash_entry **)
345 extsymcount * sizeof (struct elf_link_hash_entry *)));
346 if (sym_hash == NULL)
348 bfd_set_error (bfd_error_no_memory);
351 elf_sym_hashes (abfd) = sym_hash;
353 if (elf_elfheader (abfd)->e_type != ET_DYN)
357 /* If we are creating a shared library, create all the dynamic
358 sections immediately. We need to attach them to something,
359 so we attach them to this BFD, provided it is the right
360 format. FIXME: If there are no input BFD's of the same
361 format as the output, we can't make a shared library. */
363 && ! elf_hash_table (info)->dynamic_sections_created
364 && abfd->xvec == info->hash->creator)
366 if (! elf_link_create_dynamic_sections (abfd, info))
375 bfd_size_type oldsize;
376 bfd_size_type strindex;
380 /* You can't use -r against a dynamic object. Also, there's no
381 hope of using a dynamic object which does not exactly match
382 the format of the output file. */
383 if (info->relocateable
384 || info->hash->creator != abfd->xvec)
386 bfd_set_error (bfd_error_invalid_operation);
390 /* Find the name to use in a DT_NEEDED entry that refers to this
391 object. If the object has a DT_SONAME entry, we use it.
392 Otherwise, if the generic linker stuck something in
393 elf_dt_needed_name, we use that. Otherwise, we just use the
394 file name. If the generic linker put a null string into
395 elf_dt_needed_name, we don't make a DT_NEEDED entry at all,
396 even if there is a DT_SONAME entry. */
398 name = bfd_get_filename (abfd);
399 if (elf_dt_needed_name (abfd) != NULL)
401 name = elf_dt_needed_name (abfd);
405 s = bfd_get_section_by_name (abfd, ".dynamic");
408 Elf_External_Dyn *extdyn;
409 Elf_External_Dyn *extdynend;
413 dynbuf = (Elf_External_Dyn *) malloc ((size_t) s->_raw_size);
416 bfd_set_error (bfd_error_no_memory);
420 if (! bfd_get_section_contents (abfd, s, (PTR) dynbuf,
421 (file_ptr) 0, s->_raw_size))
424 elfsec = _bfd_elf_section_from_bfd_section (abfd, s);
427 link = elf_elfsections (abfd)[elfsec]->sh_link;
430 extdynend = extdyn + s->_raw_size / sizeof (Elf_External_Dyn);
431 for (; extdyn < extdynend; extdyn++)
433 Elf_Internal_Dyn dyn;
435 elf_swap_dyn_in (abfd, extdyn, &dyn);
436 if (add_needed && dyn.d_tag == DT_SONAME)
438 name = bfd_elf_string_from_elf_section (abfd, link,
443 if (dyn.d_tag == DT_NEEDED)
445 struct bfd_link_needed_list *n, **pn;
448 n = ((struct bfd_link_needed_list *)
449 bfd_alloc (abfd, sizeof (struct bfd_link_needed_list)));
450 fnm = bfd_elf_string_from_elf_section (abfd, link,
452 if (n == NULL || fnm == NULL)
454 anm = bfd_alloc (abfd, strlen (fnm) + 1);
461 for (pn = &elf_hash_table (info)->needed;
473 /* We do not want to include any of the sections in a dynamic
474 object in the output file. We hack by simply clobbering the
475 list of sections in the BFD. This could be handled more
476 cleanly by, say, a new section flag; the existing
477 SEC_NEVER_LOAD flag is not the one we want, because that one
478 still implies that the section takes up space in the output
480 abfd->sections = NULL;
482 /* If this is the first dynamic object found in the link, create
483 the special sections required for dynamic linking. */
484 if (! elf_hash_table (info)->dynamic_sections_created)
486 if (! elf_link_create_dynamic_sections (abfd, info))
492 /* Add a DT_NEEDED entry for this dynamic object. */
493 oldsize = _bfd_stringtab_size (elf_hash_table (info)->dynstr);
494 strindex = _bfd_stringtab_add (elf_hash_table (info)->dynstr, name,
496 if (strindex == (bfd_size_type) -1)
499 if (oldsize == _bfd_stringtab_size (elf_hash_table (info)->dynstr))
502 Elf_External_Dyn *dyncon, *dynconend;
504 /* The hash table size did not change, which means that
505 the dynamic object name was already entered. If we
506 have already included this dynamic object in the
507 link, just ignore it. There is no reason to include
508 a particular dynamic object more than once. */
509 sdyn = bfd_get_section_by_name (elf_hash_table (info)->dynobj,
511 BFD_ASSERT (sdyn != NULL);
513 dyncon = (Elf_External_Dyn *) sdyn->contents;
514 dynconend = (Elf_External_Dyn *) (sdyn->contents +
516 for (; dyncon < dynconend; dyncon++)
518 Elf_Internal_Dyn dyn;
520 elf_swap_dyn_in (elf_hash_table (info)->dynobj, dyncon,
522 if (dyn.d_tag == DT_NEEDED
523 && dyn.d_un.d_val == strindex)
532 if (! elf_add_dynamic_entry (info, DT_NEEDED, strindex))
538 hdr->sh_offset + extsymoff * sizeof (Elf_External_Sym),
540 || (bfd_read ((PTR) buf, sizeof (Elf_External_Sym), extsymcount, abfd)
541 != extsymcount * sizeof (Elf_External_Sym)))
546 esymend = buf + extsymcount;
547 for (esym = buf; esym < esymend; esym++, sym_hash++)
549 Elf_Internal_Sym sym;
555 struct elf_link_hash_entry *h;
557 boolean size_change_ok, type_change_ok;
560 elf_swap_symbol_in (abfd, esym, &sym);
562 flags = BSF_NO_FLAGS;
564 value = sym.st_value;
567 bind = ELF_ST_BIND (sym.st_info);
568 if (bind == STB_LOCAL)
570 /* This should be impossible, since ELF requires that all
571 global symbols follow all local symbols, and that sh_info
572 point to the first global symbol. Unfortunatealy, Irix 5
576 else if (bind == STB_GLOBAL)
578 if (sym.st_shndx != SHN_UNDEF
579 && sym.st_shndx != SHN_COMMON)
584 else if (bind == STB_WEAK)
588 /* Leave it up to the processor backend. */
591 if (sym.st_shndx == SHN_UNDEF)
592 sec = bfd_und_section_ptr;
593 else if (sym.st_shndx > 0 && sym.st_shndx < SHN_LORESERVE)
595 sec = section_from_elf_index (abfd, sym.st_shndx);
599 sec = bfd_abs_section_ptr;
601 else if (sym.st_shndx == SHN_ABS)
602 sec = bfd_abs_section_ptr;
603 else if (sym.st_shndx == SHN_COMMON)
605 sec = bfd_com_section_ptr;
606 /* What ELF calls the size we call the value. What ELF
607 calls the value we call the alignment. */
612 /* Leave it up to the processor backend. */
615 name = bfd_elf_string_from_elf_section (abfd, hdr->sh_link, sym.st_name);
616 if (name == (const char *) NULL)
621 if (! (*add_symbol_hook) (abfd, info, &sym, &name, &flags, &sec,
625 /* The hook function sets the name to NULL if this symbol
626 should be skipped for some reason. */
627 if (name == (const char *) NULL)
631 /* Sanity check that all possibilities were handled. */
632 if (sec == (asection *) NULL)
634 bfd_set_error (bfd_error_bad_value);
638 if (bfd_is_und_section (sec)
639 || bfd_is_com_section (sec))
644 size_change_ok = false;
645 type_change_ok = false;
646 if (info->hash->creator->flavour == bfd_target_elf_flavour)
648 /* We need to look up the symbol now in order to get some of
649 the dynamic object handling right. We pass the hash
650 table entry in to _bfd_generic_link_add_one_symbol so
651 that it does not have to look it up again. */
652 h = elf_link_hash_lookup (elf_hash_table (info), name,
658 while (h->root.type == bfd_link_hash_indirect
659 || h->root.type == bfd_link_hash_warning)
660 h = (struct elf_link_hash_entry *) h->root.u.i.link;
662 /* It's OK to change the type if it used to be a weak
664 type_change_ok = (h->root.type == bfd_link_hash_defweak
665 || h->root.type == bfd_link_hash_undefweak);
667 /* It's OK to change the size if it used to be a weak
668 definition, or if it used to be undefined, or if we will
669 be overriding an old definition.
671 size_change_ok = (type_change_ok
672 || h->root.type == bfd_link_hash_undefined);
674 /* If we are looking at a dynamic object, and this is a
675 definition, we need to see if it has already been defined
676 by some other object. If it has, we want to use the
677 existing definition, and we do not want to report a
678 multiple symbol definition error; we do this by
679 clobbering sec to be bfd_und_section_ptr. */
680 if (dynamic && definition)
682 if (h->root.type == bfd_link_hash_defined
683 || h->root.type == bfd_link_hash_defweak
684 || (h->root.type == bfd_link_hash_common
685 && bind == STB_WEAK))
687 sec = bfd_und_section_ptr;
689 size_change_ok = true;
693 /* Similarly, if we are not looking at a dynamic object, and
694 we have a definition, we want to override any definition
695 we may have from a dynamic object. Symbols from regular
696 files always take precedence over symbols from dynamic
697 objects, even if they are defined after the dynamic
698 object in the link. */
701 && (h->root.type == bfd_link_hash_defined
702 || h->root.type == bfd_link_hash_defweak)
703 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0
704 && (bfd_get_flavour (h->root.u.def.section->owner)
705 == bfd_target_elf_flavour)
706 && (elf_elfheader (h->root.u.def.section->owner)->e_type
709 /* Change the hash table entry to undefined, and let
710 _bfd_generic_link_add_one_symbol do the right thing
711 with the new definition. */
712 h->root.type = bfd_link_hash_undefined;
713 h->root.u.undef.abfd = h->root.u.def.section->owner;
714 size_change_ok = true;
718 if (! (_bfd_generic_link_add_one_symbol
719 (info, abfd, name, flags, sec, value, (const char *) NULL,
720 false, collect, (struct bfd_link_hash_entry **) sym_hash)))
724 while (h->root.type == bfd_link_hash_indirect
725 || h->root.type == bfd_link_hash_warning)
726 h = (struct elf_link_hash_entry *) h->root.u.i.link;
732 && (flags & BSF_WEAK) != 0
733 && ELF_ST_TYPE (sym.st_info) != STT_FUNC
734 && info->hash->creator->flavour == bfd_target_elf_flavour
735 && h->weakdef == NULL)
737 /* Keep a list of all weak defined non function symbols from
738 a dynamic object, using the weakdef field. Later in this
739 function we will set the weakdef field to the correct
740 value. We only put non-function symbols from dynamic
741 objects on this list, because that happens to be the only
742 time we need to know the normal symbol corresponding to a
743 weak symbol, and the information is time consuming to
744 figure out. If the weakdef field is not already NULL,
745 then this symbol was already defined by some previous
746 dynamic object, and we will be using that previous
747 definition anyhow. */
754 /* Get the alignment of a common symbol. */
755 if (sym.st_shndx == SHN_COMMON
756 && h->root.type == bfd_link_hash_common)
757 h->root.u.c.p->alignment_power = bfd_log2 (sym.st_value);
759 if (info->hash->creator->flavour == bfd_target_elf_flavour)
765 /* Remember the symbol size and type. */
767 && (definition || h->size == 0))
769 if (h->size != 0 && h->size != sym.st_size && ! size_change_ok)
770 (*_bfd_error_handler)
771 ("Warning: size of symbol `%s' changed from %lu to %lu in %s",
772 name, (unsigned long) h->size, (unsigned long) sym.st_size,
773 bfd_get_filename (abfd));
775 h->size = sym.st_size;
777 if (ELF_ST_TYPE (sym.st_info) != STT_NOTYPE
778 && (definition || h->type == STT_NOTYPE))
780 if (h->type != STT_NOTYPE
781 && h->type != ELF_ST_TYPE (sym.st_info)
783 (*_bfd_error_handler)
784 ("Warning: type of symbol `%s' changed from %d to %d in %s",
785 name, h->type, ELF_ST_TYPE (sym.st_info),
786 bfd_get_filename (abfd));
788 h->type = ELF_ST_TYPE (sym.st_info);
791 /* Set a flag in the hash table entry indicating the type of
792 reference or definition we just found. Keep a count of
793 the number of dynamic symbols we find. A dynamic symbol
794 is one which is referenced or defined by both a regular
795 object and a shared object, or one which is referenced or
796 defined by more than one shared object. */
797 old_flags = h->elf_link_hash_flags;
802 new_flag = ELF_LINK_HASH_REF_REGULAR;
804 new_flag = ELF_LINK_HASH_DEF_REGULAR;
806 || (old_flags & (ELF_LINK_HASH_DEF_DYNAMIC
807 | ELF_LINK_HASH_REF_DYNAMIC)) != 0)
813 new_flag = ELF_LINK_HASH_REF_DYNAMIC;
815 new_flag = ELF_LINK_HASH_DEF_DYNAMIC;
816 if ((old_flags & new_flag) != 0
817 || (old_flags & (ELF_LINK_HASH_DEF_REGULAR
818 | ELF_LINK_HASH_REF_REGULAR)) != 0
819 || (h->weakdef != NULL
820 && (old_flags & (ELF_LINK_HASH_DEF_DYNAMIC
821 | ELF_LINK_HASH_REF_DYNAMIC)) != 0))
825 h->elf_link_hash_flags |= new_flag;
826 if (dynsym && h->dynindx == -1)
828 if (! _bfd_elf_link_record_dynamic_symbol (info, h))
830 if (h->weakdef != NULL
832 && h->weakdef->dynindx == -1)
834 if (! _bfd_elf_link_record_dynamic_symbol (info,
842 /* Now set the weakdefs field correctly for all the weak defined
843 symbols we found. The only way to do this is to search all the
844 symbols. Since we only need the information for non functions in
845 dynamic objects, that's the only time we actually put anything on
846 the list WEAKS. We need this information so that if a regular
847 object refers to a symbol defined weakly in a dynamic object, the
848 real symbol in the dynamic object is also put in the dynamic
849 symbols; we also must arrange for both symbols to point to the
850 same memory location. We could handle the general case of symbol
851 aliasing, but a general symbol alias can only be generated in
852 assembler code, handling it correctly would be very time
853 consuming, and other ELF linkers don't handle general aliasing
855 while (weaks != NULL)
857 struct elf_link_hash_entry *hlook;
860 struct elf_link_hash_entry **hpp;
861 struct elf_link_hash_entry **hppend;
864 weaks = hlook->weakdef;
865 hlook->weakdef = NULL;
867 BFD_ASSERT (hlook->root.type == bfd_link_hash_defined
868 || hlook->root.type == bfd_link_hash_defweak
869 || hlook->root.type == bfd_link_hash_common
870 || hlook->root.type == bfd_link_hash_indirect);
871 slook = hlook->root.u.def.section;
872 vlook = hlook->root.u.def.value;
874 hpp = elf_sym_hashes (abfd);
875 hppend = hpp + extsymcount;
876 for (; hpp < hppend; hpp++)
878 struct elf_link_hash_entry *h;
881 if (h != NULL && h != hlook
882 && (h->root.type == bfd_link_hash_defined
883 || h->root.type == bfd_link_hash_defweak)
884 && h->root.u.def.section == slook
885 && h->root.u.def.value == vlook)
889 /* If the weak definition is in the list of dynamic
890 symbols, make sure the real definition is put there
892 if (hlook->dynindx != -1
895 if (! _bfd_elf_link_record_dynamic_symbol (info, h))
910 /* If this object is the same format as the output object, and it is
911 not a shared library, then let the backend look through the
914 This is required to build global offset table entries and to
915 arrange for dynamic relocs. It is not required for the
916 particular common case of linking non PIC code, even when linking
917 against shared libraries, but unfortunately there is no way of
918 knowing whether an object file has been compiled PIC or not.
919 Looking through the relocs is not particularly time consuming.
920 The problem is that we must either (1) keep the relocs in memory,
921 which causes the linker to require additional runtime memory or
922 (2) read the relocs twice from the input file, which wastes time.
923 This would be a good case for using mmap.
925 I have no idea how to handle linking PIC code into a file of a
926 different format. It probably can't be done. */
927 check_relocs = get_elf_backend_data (abfd)->check_relocs;
929 && abfd->xvec == info->hash->creator
930 && check_relocs != NULL)
934 for (o = abfd->sections; o != NULL; o = o->next)
936 Elf_Internal_Rela *internal_relocs;
939 if ((o->flags & SEC_RELOC) == 0
940 || o->reloc_count == 0)
943 /* I believe we can ignore the relocs for any section which
944 does not form part of the final process image, such as a
945 debugging section. */
946 if ((o->flags & SEC_ALLOC) == 0)
949 internal_relocs = elf_link_read_relocs (abfd, o, (PTR) NULL,
950 (Elf_Internal_Rela *) NULL,
952 if (internal_relocs == NULL)
955 ok = (*check_relocs) (abfd, info, o, internal_relocs);
957 if (! info->keep_memory)
958 free (internal_relocs);
975 /* Create some sections which will be filled in with dynamic linking
976 information. ABFD is an input file which requires dynamic sections
977 to be created. The dynamic sections take up virtual memory space
978 when the final executable is run, so we need to create them before
979 addresses are assigned to the output sections. We work out the
980 actual contents and size of these sections later. */
983 elf_link_create_dynamic_sections (abfd, info)
985 struct bfd_link_info *info;
988 register asection *s;
989 struct elf_link_hash_entry *h;
990 struct elf_backend_data *bed;
992 if (elf_hash_table (info)->dynamic_sections_created)
995 /* Make sure that all dynamic sections use the same input BFD. */
996 if (elf_hash_table (info)->dynobj == NULL)
997 elf_hash_table (info)->dynobj = abfd;
999 abfd = elf_hash_table (info)->dynobj;
1001 /* Note that we set the SEC_IN_MEMORY flag for all of these
1003 flags = SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS | SEC_IN_MEMORY;
1005 /* A dynamically linked executable has a .interp section, but a
1006 shared library does not. */
1009 s = bfd_make_section (abfd, ".interp");
1011 || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY))
1015 s = bfd_make_section (abfd, ".dynsym");
1017 || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
1018 || ! bfd_set_section_alignment (abfd, s, LOG_FILE_ALIGN))
1021 s = bfd_make_section (abfd, ".dynstr");
1023 || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY))
1026 /* Create a strtab to hold the dynamic symbol names. */
1027 if (elf_hash_table (info)->dynstr == NULL)
1029 elf_hash_table (info)->dynstr = elf_stringtab_init ();
1030 if (elf_hash_table (info)->dynstr == NULL)
1034 s = bfd_make_section (abfd, ".dynamic");
1036 || ! bfd_set_section_flags (abfd, s, flags)
1037 || ! bfd_set_section_alignment (abfd, s, LOG_FILE_ALIGN))
1040 /* The special symbol _DYNAMIC is always set to the start of the
1041 .dynamic section. This call occurs before we have processed the
1042 symbols for any dynamic object, so we don't have to worry about
1043 overriding a dynamic definition. We could set _DYNAMIC in a
1044 linker script, but we only want to define it if we are, in fact,
1045 creating a .dynamic section. We don't want to define it if there
1046 is no .dynamic section, since on some ELF platforms the start up
1047 code examines it to decide how to initialize the process. */
1049 if (! (_bfd_generic_link_add_one_symbol
1050 (info, abfd, "_DYNAMIC", BSF_GLOBAL, s, (bfd_vma) 0,
1051 (const char *) NULL, false, get_elf_backend_data (abfd)->collect,
1052 (struct bfd_link_hash_entry **) &h)))
1054 h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
1055 h->type = STT_OBJECT;
1058 && ! _bfd_elf_link_record_dynamic_symbol (info, h))
1061 s = bfd_make_section (abfd, ".hash");
1063 || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
1064 || ! bfd_set_section_alignment (abfd, s, LOG_FILE_ALIGN))
1067 /* Let the backend create the rest of the sections. This lets the
1068 backend set the right flags. The backend will normally create
1069 the .got and .plt sections. */
1070 bed = get_elf_backend_data (abfd);
1071 if (! (*bed->elf_backend_create_dynamic_sections) (abfd, info))
1074 elf_hash_table (info)->dynamic_sections_created = true;
1079 /* Add an entry to the .dynamic table. */
1082 elf_add_dynamic_entry (info, tag, val)
1083 struct bfd_link_info *info;
1087 Elf_Internal_Dyn dyn;
1091 bfd_byte *newcontents;
1093 dynobj = elf_hash_table (info)->dynobj;
1095 s = bfd_get_section_by_name (dynobj, ".dynamic");
1096 BFD_ASSERT (s != NULL);
1098 newsize = s->_raw_size + sizeof (Elf_External_Dyn);
1099 if (s->contents == NULL)
1100 newcontents = (bfd_byte *) malloc (newsize);
1102 newcontents = (bfd_byte *) realloc (s->contents, newsize);
1103 if (newcontents == NULL)
1105 bfd_set_error (bfd_error_no_memory);
1110 dyn.d_un.d_val = val;
1111 elf_swap_dyn_out (dynobj, &dyn,
1112 (Elf_External_Dyn *) (newcontents + s->_raw_size));
1114 s->_raw_size = newsize;
1115 s->contents = newcontents;
1120 /* Read and swap the relocs for a section. They may have been cached.
1121 If the EXTERNAL_RELOCS and INTERNAL_RELOCS arguments are not NULL,
1122 they are used as buffers to read into. They are known to be large
1123 enough. If the INTERNAL_RELOCS relocs argument is NULL, the return
1124 value is allocated using either malloc or bfd_alloc, according to
1125 the KEEP_MEMORY argument. */
1127 static Elf_Internal_Rela *
1128 elf_link_read_relocs (abfd, o, external_relocs, internal_relocs, keep_memory)
1131 PTR external_relocs;
1132 Elf_Internal_Rela *internal_relocs;
1133 boolean keep_memory;
1135 Elf_Internal_Shdr *rel_hdr;
1137 Elf_Internal_Rela *alloc2 = NULL;
1139 if (elf_section_data (o)->relocs != NULL)
1140 return elf_section_data (o)->relocs;
1142 if (o->reloc_count == 0)
1145 rel_hdr = &elf_section_data (o)->rel_hdr;
1147 if (internal_relocs == NULL)
1151 size = o->reloc_count * sizeof (Elf_Internal_Rela);
1153 internal_relocs = (Elf_Internal_Rela *) bfd_alloc (abfd, size);
1155 internal_relocs = alloc2 = (Elf_Internal_Rela *) malloc (size);
1156 if (internal_relocs == NULL)
1158 bfd_set_error (bfd_error_no_memory);
1163 if (external_relocs == NULL)
1165 alloc1 = (PTR) malloc ((size_t) rel_hdr->sh_size);
1168 bfd_set_error (bfd_error_no_memory);
1171 external_relocs = alloc1;
1174 if ((bfd_seek (abfd, rel_hdr->sh_offset, SEEK_SET) != 0)
1175 || (bfd_read (external_relocs, 1, rel_hdr->sh_size, abfd)
1176 != rel_hdr->sh_size))
1179 /* Swap in the relocs. For convenience, we always produce an
1180 Elf_Internal_Rela array; if the relocs are Rel, we set the addend
1182 if (rel_hdr->sh_entsize == sizeof (Elf_External_Rel))
1184 Elf_External_Rel *erel;
1185 Elf_External_Rel *erelend;
1186 Elf_Internal_Rela *irela;
1188 erel = (Elf_External_Rel *) external_relocs;
1189 erelend = erel + o->reloc_count;
1190 irela = internal_relocs;
1191 for (; erel < erelend; erel++, irela++)
1193 Elf_Internal_Rel irel;
1195 elf_swap_reloc_in (abfd, erel, &irel);
1196 irela->r_offset = irel.r_offset;
1197 irela->r_info = irel.r_info;
1198 irela->r_addend = 0;
1203 Elf_External_Rela *erela;
1204 Elf_External_Rela *erelaend;
1205 Elf_Internal_Rela *irela;
1207 BFD_ASSERT (rel_hdr->sh_entsize == sizeof (Elf_External_Rela));
1209 erela = (Elf_External_Rela *) external_relocs;
1210 erelaend = erela + o->reloc_count;
1211 irela = internal_relocs;
1212 for (; erela < erelaend; erela++, irela++)
1213 elf_swap_reloca_in (abfd, erela, irela);
1216 /* Cache the results for next time, if we can. */
1218 elf_section_data (o)->relocs = internal_relocs;
1223 /* Don't free alloc2, since if it was allocated we are passing it
1224 back (under the name of internal_relocs). */
1226 return internal_relocs;
1236 /* Record an assignment to a symbol made by a linker script. We need
1237 this in case some dynamic object refers to this symbol. */
1241 NAME(bfd_elf,record_link_assignment) (output_bfd, info, name, provide)
1243 struct bfd_link_info *info;
1247 struct elf_link_hash_entry *h;
1249 if (info->hash->creator->flavour != bfd_target_elf_flavour)
1252 h = elf_link_hash_lookup (elf_hash_table (info), name, true, true, false);
1256 /* If this symbol is being provided by the linker script, and it is
1257 currently defined by a dynamic object, but not by a regular
1258 object, then mark it as undefined so that the generic linker will
1259 force the correct value. */
1261 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0
1262 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
1263 h->root.type = bfd_link_hash_undefined;
1265 h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
1266 h->type = STT_OBJECT;
1268 if (((h->elf_link_hash_flags & (ELF_LINK_HASH_DEF_DYNAMIC
1269 | ELF_LINK_HASH_REF_DYNAMIC)) != 0
1271 && h->dynindx == -1)
1273 if (! _bfd_elf_link_record_dynamic_symbol (info, h))
1276 /* If this is a weak defined symbol, and we know a corresponding
1277 real symbol from the same dynamic object, make sure the real
1278 symbol is also made into a dynamic symbol. */
1279 if (h->weakdef != NULL
1280 && h->weakdef->dynindx == -1)
1282 if (! _bfd_elf_link_record_dynamic_symbol (info, h->weakdef))
1290 /* Array used to determine the number of hash table buckets to use
1291 based on the number of symbols there are. If there are fewer than
1292 3 symbols we use 1 bucket, fewer than 17 symbols we use 3 buckets,
1293 fewer than 37 we use 17 buckets, and so forth. We never use more
1294 than 521 buckets. */
1296 static const size_t elf_buckets[] =
1298 1, 3, 17, 37, 67, 97, 131, 197, 263, 521, 0
1301 /* Set up the sizes and contents of the ELF dynamic sections. This is
1302 called by the ELF linker emulation before_allocation routine. We
1303 must set the sizes of the sections before the linker sets the
1304 addresses of the various sections. */
1307 NAME(bfd_elf,size_dynamic_sections) (output_bfd, soname, rpath,
1308 export_dynamic, info, sinterpptr)
1312 boolean export_dynamic;
1313 struct bfd_link_info *info;
1314 asection **sinterpptr;
1317 struct elf_backend_data *bed;
1321 if (info->hash->creator->flavour != bfd_target_elf_flavour)
1324 dynobj = elf_hash_table (info)->dynobj;
1326 /* If there were no dynamic objects in the link, there is nothing to
1331 /* If we are supposed to export all symbols into the dynamic symbol
1332 table (this is not the normal case), then do so. */
1335 struct elf_info_failed eif;
1339 elf_link_hash_traverse (elf_hash_table (info), elf_export_symbol,
1345 if (elf_hash_table (info)->dynamic_sections_created)
1347 struct elf_info_failed eif;
1348 bfd_size_type strsize;
1350 *sinterpptr = bfd_get_section_by_name (dynobj, ".interp");
1351 BFD_ASSERT (*sinterpptr != NULL || info->shared);
1357 indx = _bfd_stringtab_add (elf_hash_table (info)->dynstr, soname,
1359 if (indx == (bfd_size_type) -1
1360 || ! elf_add_dynamic_entry (info, DT_SONAME, indx))
1366 if (! elf_add_dynamic_entry (info, DT_SYMBOLIC, 0))
1374 indx = _bfd_stringtab_add (elf_hash_table (info)->dynstr, rpath,
1376 if (indx == (bfd_size_type) -1
1377 || ! elf_add_dynamic_entry (info, DT_RPATH, indx))
1381 /* Find all symbols which were defined in a dynamic object and make
1382 the backend pick a reasonable value for them. */
1385 elf_link_hash_traverse (elf_hash_table (info),
1386 elf_adjust_dynamic_symbol,
1391 /* Add some entries to the .dynamic section. We fill in some of the
1392 values later, in elf_bfd_final_link, but we must add the entries
1393 now so that we know the final size of the .dynamic section. */
1394 if (elf_link_hash_lookup (elf_hash_table (info), "_init", false,
1395 false, false) != NULL)
1397 if (! elf_add_dynamic_entry (info, DT_INIT, 0))
1400 if (elf_link_hash_lookup (elf_hash_table (info), "_fini", false,
1401 false, false) != NULL)
1403 if (! elf_add_dynamic_entry (info, DT_FINI, 0))
1406 strsize = _bfd_stringtab_size (elf_hash_table (info)->dynstr);
1407 if (! elf_add_dynamic_entry (info, DT_HASH, 0)
1408 || ! elf_add_dynamic_entry (info, DT_STRTAB, 0)
1409 || ! elf_add_dynamic_entry (info, DT_SYMTAB, 0)
1410 || ! elf_add_dynamic_entry (info, DT_STRSZ, strsize)
1411 || ! elf_add_dynamic_entry (info, DT_SYMENT,
1412 sizeof (Elf_External_Sym)))
1416 /* The backend must work out the sizes of all the other dynamic
1418 bed = get_elf_backend_data (output_bfd);
1419 if (! (*bed->elf_backend_size_dynamic_sections) (output_bfd, info))
1422 if (elf_hash_table (info)->dynamic_sections_created)
1427 size_t bucketcount = 0;
1428 Elf_Internal_Sym isym;
1430 /* Set the size of the .dynsym and .hash sections. We counted
1431 the number of dynamic symbols in elf_link_add_object_symbols.
1432 We will build the contents of .dynsym and .hash when we build
1433 the final symbol table, because until then we do not know the
1434 correct value to give the symbols. We built the .dynstr
1435 section as we went along in elf_link_add_object_symbols. */
1436 dynsymcount = elf_hash_table (info)->dynsymcount;
1437 s = bfd_get_section_by_name (dynobj, ".dynsym");
1438 BFD_ASSERT (s != NULL);
1439 s->_raw_size = dynsymcount * sizeof (Elf_External_Sym);
1440 s->contents = (bfd_byte *) bfd_alloc (output_bfd, s->_raw_size);
1441 if (s->contents == NULL && s->_raw_size != 0)
1443 bfd_set_error (bfd_error_no_memory);
1447 /* The first entry in .dynsym is a dummy symbol. */
1454 elf_swap_symbol_out (output_bfd, &isym,
1455 (PTR) (Elf_External_Sym *) s->contents);
1457 for (i = 0; elf_buckets[i] != 0; i++)
1459 bucketcount = elf_buckets[i];
1460 if (dynsymcount < elf_buckets[i + 1])
1464 s = bfd_get_section_by_name (dynobj, ".hash");
1465 BFD_ASSERT (s != NULL);
1466 s->_raw_size = (2 + bucketcount + dynsymcount) * (ARCH_SIZE / 8);
1467 s->contents = (bfd_byte *) bfd_alloc (output_bfd, s->_raw_size);
1468 if (s->contents == NULL)
1470 bfd_set_error (bfd_error_no_memory);
1473 memset (s->contents, 0, (size_t) s->_raw_size);
1475 put_word (output_bfd, bucketcount, s->contents);
1476 put_word (output_bfd, dynsymcount, s->contents + (ARCH_SIZE / 8));
1478 elf_hash_table (info)->bucketcount = bucketcount;
1480 s = bfd_get_section_by_name (dynobj, ".dynstr");
1481 BFD_ASSERT (s != NULL);
1482 s->_raw_size = _bfd_stringtab_size (elf_hash_table (info)->dynstr);
1484 if (! elf_add_dynamic_entry (info, DT_NULL, 0))
1491 /* This routine is used to export all defined symbols into the dynamic
1492 symbol table. It is called via elf_link_hash_traverse. */
1495 elf_export_symbol (h, data)
1496 struct elf_link_hash_entry *h;
1499 struct elf_info_failed *eif = (struct elf_info_failed *) data;
1501 if (h->dynindx == -1
1502 && (h->elf_link_hash_flags
1503 & (ELF_LINK_HASH_DEF_REGULAR | ELF_LINK_HASH_REF_REGULAR)) != 0)
1505 if (! _bfd_elf_link_record_dynamic_symbol (eif->info, h))
1515 /* Make the backend pick a good value for a dynamic symbol. This is
1516 called via elf_link_hash_traverse, and also calls itself
1520 elf_adjust_dynamic_symbol (h, data)
1521 struct elf_link_hash_entry *h;
1524 struct elf_info_failed *eif = (struct elf_info_failed *) data;
1526 struct elf_backend_data *bed;
1528 /* If -Bsymbolic was used (which means to bind references to global
1529 symbols to the definition within the shared object), and this
1530 symbol was defined in a regular object, then it actually doesn't
1531 need a PLT entry. */
1532 if ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) != 0
1533 && eif->info->shared
1534 && eif->info->symbolic
1535 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0)
1536 h->elf_link_hash_flags &=~ ELF_LINK_HASH_NEEDS_PLT;
1538 /* If this symbol does not require a PLT entry, and it is not
1539 defined by a dynamic object, or is not referenced by a regular
1540 object, ignore it. We do have to handle a weak defined symbol,
1541 even if no regular object refers to it, if we decided to add it
1542 to the dynamic symbol table. FIXME: Do we normally need to worry
1543 about symbols which are defined by one dynamic object and
1544 referenced by another one? */
1545 if ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) == 0
1546 && ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0
1547 || (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) == 0
1548 || ((h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) == 0
1549 && (h->weakdef == NULL || h->weakdef->dynindx == -1))))
1552 /* If we've already adjusted this symbol, don't do it again. This
1553 can happen via a recursive call. */
1554 if ((h->elf_link_hash_flags & ELF_LINK_HASH_DYNAMIC_ADJUSTED) != 0)
1557 /* Don't look at this symbol again. Note that we must set this
1558 after checking the above conditions, because we may look at a
1559 symbol once, decide not to do anything, and then get called
1560 recursively later after REF_REGULAR is set below. */
1561 h->elf_link_hash_flags |= ELF_LINK_HASH_DYNAMIC_ADJUSTED;
1563 /* If this is a weak definition, and we know a real definition, and
1564 the real symbol is not itself defined by a regular object file,
1565 then get a good value for the real definition. We handle the
1566 real symbol first, for the convenience of the backend routine.
1568 Note that there is a confusing case here. If the real definition
1569 is defined by a regular object file, we don't get the real symbol
1570 from the dynamic object, but we do get the weak symbol. If the
1571 processor backend uses a COPY reloc, then if some routine in the
1572 dynamic object changes the real symbol, we will not see that
1573 change in the corresponding weak symbol. This is the way other
1574 ELF linkers work as well, and seems to be a result of the shared
1577 I will clarify this issue. Most SVR4 shared libraries define the
1578 variable _timezone and define timezone as a weak synonym. The
1579 tzset call changes _timezone. If you write
1580 extern int timezone;
1582 int main () { tzset (); printf ("%d %d\n", timezone, _timezone); }
1583 you might expect that, since timezone is a synonym for _timezone,
1584 the same number will print both times. However, if the processor
1585 backend uses a COPY reloc, then actually timezone will be copied
1586 into your process image, and, since you define _timezone
1587 yourself, _timezone will not. Thus timezone and _timezone will
1588 wind up at different memory locations. The tzset call will set
1589 _timezone, leaving timezone unchanged. */
1591 if (h->weakdef != NULL)
1593 struct elf_link_hash_entry *weakdef;
1595 BFD_ASSERT (h->root.type == bfd_link_hash_defined
1596 || h->root.type == bfd_link_hash_defweak);
1597 weakdef = h->weakdef;
1598 BFD_ASSERT (weakdef->root.type == bfd_link_hash_defined
1599 || weakdef->root.type == bfd_link_hash_defweak);
1600 BFD_ASSERT (weakdef->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC);
1601 if ((weakdef->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0)
1603 /* This symbol is defined by a regular object file, so we
1604 will not do anything special. Clear weakdef for the
1605 convenience of the processor backend. */
1610 /* There is an implicit reference by a regular object file
1611 via the weak symbol. */
1612 weakdef->elf_link_hash_flags |= ELF_LINK_HASH_REF_REGULAR;
1613 if (! elf_adjust_dynamic_symbol (weakdef, (PTR) eif))
1618 dynobj = elf_hash_table (eif->info)->dynobj;
1619 bed = get_elf_backend_data (dynobj);
1620 if (! (*bed->elf_backend_adjust_dynamic_symbol) (eif->info, h))
1629 /* Final phase of ELF linker. */
1631 /* A structure we use to avoid passing large numbers of arguments. */
1633 struct elf_final_link_info
1635 /* General link information. */
1636 struct bfd_link_info *info;
1639 /* Symbol string table. */
1640 struct bfd_strtab_hash *symstrtab;
1641 /* .dynsym section. */
1642 asection *dynsym_sec;
1643 /* .hash section. */
1645 /* Buffer large enough to hold contents of any section. */
1647 /* Buffer large enough to hold external relocs of any section. */
1648 PTR external_relocs;
1649 /* Buffer large enough to hold internal relocs of any section. */
1650 Elf_Internal_Rela *internal_relocs;
1651 /* Buffer large enough to hold external local symbols of any input
1653 Elf_External_Sym *external_syms;
1654 /* Buffer large enough to hold internal local symbols of any input
1656 Elf_Internal_Sym *internal_syms;
1657 /* Array large enough to hold a symbol index for each local symbol
1658 of any input BFD. */
1660 /* Array large enough to hold a section pointer for each local
1661 symbol of any input BFD. */
1662 asection **sections;
1663 /* Buffer to hold swapped out symbols. */
1664 Elf_External_Sym *symbuf;
1665 /* Number of swapped out symbols in buffer. */
1666 size_t symbuf_count;
1667 /* Number of symbols which fit in symbuf. */
1671 static boolean elf_link_output_sym
1672 PARAMS ((struct elf_final_link_info *, const char *,
1673 Elf_Internal_Sym *, asection *));
1674 static boolean elf_link_flush_output_syms
1675 PARAMS ((struct elf_final_link_info *));
1676 static boolean elf_link_output_extsym
1677 PARAMS ((struct elf_link_hash_entry *, PTR));
1678 static boolean elf_link_input_bfd
1679 PARAMS ((struct elf_final_link_info *, bfd *));
1680 static boolean elf_reloc_link_order
1681 PARAMS ((bfd *, struct bfd_link_info *, asection *,
1682 struct bfd_link_order *));
1684 /* This struct is used to pass information to routines called via
1685 elf_link_hash_traverse which must return failure. */
1687 struct elf_finfo_failed
1690 struct elf_final_link_info *finfo;
1693 /* Do the final step of an ELF link. */
1696 elf_bfd_final_link (abfd, info)
1698 struct bfd_link_info *info;
1702 struct elf_final_link_info finfo;
1703 register asection *o;
1704 register struct bfd_link_order *p;
1706 size_t max_contents_size;
1707 size_t max_external_reloc_size;
1708 size_t max_internal_reloc_count;
1709 size_t max_sym_count;
1711 Elf_Internal_Sym elfsym;
1713 Elf_Internal_Shdr *symtab_hdr;
1714 Elf_Internal_Shdr *symstrtab_hdr;
1715 struct elf_backend_data *bed = get_elf_backend_data (abfd);
1716 struct elf_finfo_failed eif;
1719 abfd->flags |= DYNAMIC;
1721 dynamic = elf_hash_table (info)->dynamic_sections_created;
1722 dynobj = elf_hash_table (info)->dynobj;
1725 finfo.output_bfd = abfd;
1726 finfo.symstrtab = elf_stringtab_init ();
1727 if (finfo.symstrtab == NULL)
1731 finfo.dynsym_sec = NULL;
1732 finfo.hash_sec = NULL;
1736 finfo.dynsym_sec = bfd_get_section_by_name (dynobj, ".dynsym");
1737 finfo.hash_sec = bfd_get_section_by_name (dynobj, ".hash");
1738 BFD_ASSERT (finfo.dynsym_sec != NULL && finfo.hash_sec != NULL);
1740 finfo.contents = NULL;
1741 finfo.external_relocs = NULL;
1742 finfo.internal_relocs = NULL;
1743 finfo.external_syms = NULL;
1744 finfo.internal_syms = NULL;
1745 finfo.indices = NULL;
1746 finfo.sections = NULL;
1747 finfo.symbuf = NULL;
1748 finfo.symbuf_count = 0;
1750 /* Count up the number of relocations we will output for each output
1751 section, so that we know the sizes of the reloc sections. We
1752 also figure out some maximum sizes. */
1753 max_contents_size = 0;
1754 max_external_reloc_size = 0;
1755 max_internal_reloc_count = 0;
1757 for (o = abfd->sections; o != (asection *) NULL; o = o->next)
1761 for (p = o->link_order_head; p != NULL; p = p->next)
1763 if (p->type == bfd_section_reloc_link_order
1764 || p->type == bfd_symbol_reloc_link_order)
1766 else if (p->type == bfd_indirect_link_order)
1770 sec = p->u.indirect.section;
1772 if (info->relocateable)
1773 o->reloc_count += sec->reloc_count;
1775 if (sec->_raw_size > max_contents_size)
1776 max_contents_size = sec->_raw_size;
1777 if (sec->_cooked_size > max_contents_size)
1778 max_contents_size = sec->_cooked_size;
1780 /* We are interested in just local symbols, not all
1782 if (bfd_get_flavour (sec->owner) == bfd_target_elf_flavour)
1786 if (elf_bad_symtab (sec->owner))
1787 sym_count = (elf_tdata (sec->owner)->symtab_hdr.sh_size
1788 / sizeof (Elf_External_Sym));
1790 sym_count = elf_tdata (sec->owner)->symtab_hdr.sh_info;
1792 if (sym_count > max_sym_count)
1793 max_sym_count = sym_count;
1795 if ((sec->flags & SEC_RELOC) != 0)
1799 ext_size = elf_section_data (sec)->rel_hdr.sh_size;
1800 if (ext_size > max_external_reloc_size)
1801 max_external_reloc_size = ext_size;
1802 if (sec->reloc_count > max_internal_reloc_count)
1803 max_internal_reloc_count = sec->reloc_count;
1809 if (o->reloc_count > 0)
1810 o->flags |= SEC_RELOC;
1813 /* Explicitly clear the SEC_RELOC flag. The linker tends to
1814 set it (this is probably a bug) and if it is set
1815 assign_section_numbers will create a reloc section. */
1816 o->flags &=~ SEC_RELOC;
1819 /* If the SEC_ALLOC flag is not set, force the section VMA to
1820 zero. This is done in elf_fake_sections as well, but forcing
1821 the VMA to 0 here will ensure that relocs against these
1822 sections are handled correctly. */
1823 if ((o->flags & SEC_ALLOC) == 0)
1827 /* Figure out the file positions for everything but the symbol table
1828 and the relocs. We set symcount to force assign_section_numbers
1829 to create a symbol table. */
1830 abfd->symcount = info->strip == strip_all ? 0 : 1;
1831 BFD_ASSERT (! abfd->output_has_begun);
1832 if (! _bfd_elf_compute_section_file_positions (abfd, info))
1835 /* That created the reloc sections. Set their sizes, and assign
1836 them file positions, and allocate some buffers. */
1837 for (o = abfd->sections; o != NULL; o = o->next)
1839 if ((o->flags & SEC_RELOC) != 0)
1841 Elf_Internal_Shdr *rel_hdr;
1842 register struct elf_link_hash_entry **p, **pend;
1844 rel_hdr = &elf_section_data (o)->rel_hdr;
1846 rel_hdr->sh_size = rel_hdr->sh_entsize * o->reloc_count;
1848 /* The contents field must last into write_object_contents,
1849 so we allocate it with bfd_alloc rather than malloc. */
1850 rel_hdr->contents = (PTR) bfd_alloc (abfd, rel_hdr->sh_size);
1851 if (rel_hdr->contents == NULL && rel_hdr->sh_size != 0)
1853 bfd_set_error (bfd_error_no_memory);
1857 p = ((struct elf_link_hash_entry **)
1858 malloc (o->reloc_count
1859 * sizeof (struct elf_link_hash_entry *)));
1860 if (p == NULL && o->reloc_count != 0)
1862 bfd_set_error (bfd_error_no_memory);
1865 elf_section_data (o)->rel_hashes = p;
1866 pend = p + o->reloc_count;
1867 for (; p < pend; p++)
1870 /* Use the reloc_count field as an index when outputting the
1876 _bfd_elf_assign_file_positions_for_relocs (abfd);
1878 /* We have now assigned file positions for all the sections except
1879 .symtab and .strtab. We start the .symtab section at the current
1880 file position, and write directly to it. We build the .strtab
1881 section in memory. When we add .dynsym support, we will build
1882 that in memory as well (.dynsym is smaller than .symtab). */
1884 symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
1885 /* sh_name is set in prep_headers. */
1886 symtab_hdr->sh_type = SHT_SYMTAB;
1887 symtab_hdr->sh_flags = 0;
1888 symtab_hdr->sh_addr = 0;
1889 symtab_hdr->sh_size = 0;
1890 symtab_hdr->sh_entsize = sizeof (Elf_External_Sym);
1891 /* sh_link is set in assign_section_numbers. */
1892 /* sh_info is set below. */
1893 /* sh_offset is set just below. */
1894 symtab_hdr->sh_addralign = 4; /* FIXME: system dependent? */
1896 off = elf_tdata (abfd)->next_file_pos;
1897 off = _bfd_elf_assign_file_position_for_section (symtab_hdr, off, true);
1899 /* Note that at this point elf_tdata (abfd)->next_file_pos is
1900 incorrect. We do not yet know the size of the .symtab section.
1901 We correct next_file_pos below, after we do know the size. */
1903 /* Allocate a buffer to hold swapped out symbols. This is to avoid
1904 continuously seeking to the right position in the file. */
1905 if (! info->keep_memory || max_sym_count < 20)
1906 finfo.symbuf_size = 20;
1908 finfo.symbuf_size = max_sym_count;
1909 finfo.symbuf = ((Elf_External_Sym *)
1910 malloc (finfo.symbuf_size * sizeof (Elf_External_Sym)));
1911 if (finfo.symbuf == NULL)
1913 bfd_set_error (bfd_error_no_memory);
1917 /* Start writing out the symbol table. The first symbol is always a
1919 elfsym.st_value = 0;
1922 elfsym.st_other = 0;
1923 elfsym.st_shndx = SHN_UNDEF;
1924 if (! elf_link_output_sym (&finfo, (const char *) NULL,
1925 &elfsym, bfd_und_section_ptr))
1929 /* Some standard ELF linkers do this, but we don't because it causes
1930 bootstrap comparison failures. */
1931 /* Output a file symbol for the output file as the second symbol.
1932 We output this even if we are discarding local symbols, although
1933 I'm not sure if this is correct. */
1934 elfsym.st_value = 0;
1936 elfsym.st_info = ELF_ST_INFO (STB_LOCAL, STT_FILE);
1937 elfsym.st_other = 0;
1938 elfsym.st_shndx = SHN_ABS;
1939 if (! elf_link_output_sym (&finfo, bfd_get_filename (abfd),
1940 &elfsym, bfd_abs_section_ptr))
1944 /* Output a symbol for each section. We output these even if we are
1945 discarding local symbols, since they are used for relocs. These
1946 symbols have no names. We store the index of each one in the
1947 index field of the section, so that we can find it again when
1948 outputting relocs. */
1949 elfsym.st_value = 0;
1951 elfsym.st_info = ELF_ST_INFO (STB_LOCAL, STT_SECTION);
1952 elfsym.st_other = 0;
1953 for (i = 1; i < elf_elfheader (abfd)->e_shnum; i++)
1955 o = section_from_elf_index (abfd, i);
1957 o->target_index = abfd->symcount;
1958 elfsym.st_shndx = i;
1959 if (! elf_link_output_sym (&finfo, (const char *) NULL,
1964 /* Allocate some memory to hold information read in from the input
1966 finfo.contents = (bfd_byte *) malloc (max_contents_size);
1967 finfo.external_relocs = (PTR) malloc (max_external_reloc_size);
1968 finfo.internal_relocs = ((Elf_Internal_Rela *)
1969 malloc (max_internal_reloc_count
1970 * sizeof (Elf_Internal_Rela)));
1971 finfo.external_syms = ((Elf_External_Sym *)
1972 malloc (max_sym_count * sizeof (Elf_External_Sym)));
1973 finfo.internal_syms = ((Elf_Internal_Sym *)
1974 malloc (max_sym_count * sizeof (Elf_Internal_Sym)));
1975 finfo.indices = (long *) malloc (max_sym_count * sizeof (long));
1976 finfo.sections = (asection **) malloc (max_sym_count * sizeof (asection *));
1977 if ((finfo.contents == NULL && max_contents_size != 0)
1978 || (finfo.external_relocs == NULL && max_external_reloc_size != 0)
1979 || (finfo.internal_relocs == NULL && max_internal_reloc_count != 0)
1980 || (finfo.external_syms == NULL && max_sym_count != 0)
1981 || (finfo.internal_syms == NULL && max_sym_count != 0)
1982 || (finfo.indices == NULL && max_sym_count != 0)
1983 || (finfo.sections == NULL && max_sym_count != 0))
1985 bfd_set_error (bfd_error_no_memory);
1989 /* Since ELF permits relocations to be against local symbols, we
1990 must have the local symbols available when we do the relocations.
1991 Since we would rather only read the local symbols once, and we
1992 would rather not keep them in memory, we handle all the
1993 relocations for a single input file at the same time.
1995 Unfortunately, there is no way to know the total number of local
1996 symbols until we have seen all of them, and the local symbol
1997 indices precede the global symbol indices. This means that when
1998 we are generating relocateable output, and we see a reloc against
1999 a global symbol, we can not know the symbol index until we have
2000 finished examining all the local symbols to see which ones we are
2001 going to output. To deal with this, we keep the relocations in
2002 memory, and don't output them until the end of the link. This is
2003 an unfortunate waste of memory, but I don't see a good way around
2004 it. Fortunately, it only happens when performing a relocateable
2005 link, which is not the common case. FIXME: If keep_memory is set
2006 we could write the relocs out and then read them again; I don't
2007 know how bad the memory loss will be. */
2009 for (sub = info->input_bfds; sub != NULL; sub = sub->next)
2010 sub->output_has_begun = false;
2011 for (o = abfd->sections; o != NULL; o = o->next)
2013 for (p = o->link_order_head; p != NULL; p = p->next)
2015 if (p->type == bfd_indirect_link_order
2016 && (bfd_get_flavour (p->u.indirect.section->owner)
2017 == bfd_target_elf_flavour))
2019 sub = p->u.indirect.section->owner;
2020 if (! sub->output_has_begun)
2022 if (! elf_link_input_bfd (&finfo, sub))
2024 sub->output_has_begun = true;
2027 else if (p->type == bfd_section_reloc_link_order
2028 || p->type == bfd_symbol_reloc_link_order)
2030 if (! elf_reloc_link_order (abfd, info, o, p))
2035 if (! _bfd_default_link_order (abfd, info, o, p))
2041 /* That wrote out all the local symbols. Finish up the symbol table
2042 with the global symbols. */
2044 /* The sh_info field records the index of the first non local
2046 symtab_hdr->sh_info = abfd->symcount;
2048 elf_section_data (finfo.dynsym_sec->output_section)->this_hdr.sh_info = 1;
2050 /* We get the global symbols from the hash table. */
2053 elf_link_hash_traverse (elf_hash_table (info), elf_link_output_extsym,
2058 /* Flush all symbols to the file. */
2059 if (! elf_link_flush_output_syms (&finfo))
2062 /* Now we know the size of the symtab section. */
2063 off += symtab_hdr->sh_size;
2065 /* Finish up and write out the symbol string table (.strtab)
2067 symstrtab_hdr = &elf_tdata (abfd)->strtab_hdr;
2068 /* sh_name was set in prep_headers. */
2069 symstrtab_hdr->sh_type = SHT_STRTAB;
2070 symstrtab_hdr->sh_flags = 0;
2071 symstrtab_hdr->sh_addr = 0;
2072 symstrtab_hdr->sh_size = _bfd_stringtab_size (finfo.symstrtab);
2073 symstrtab_hdr->sh_entsize = 0;
2074 symstrtab_hdr->sh_link = 0;
2075 symstrtab_hdr->sh_info = 0;
2076 /* sh_offset is set just below. */
2077 symstrtab_hdr->sh_addralign = 1;
2079 off = _bfd_elf_assign_file_position_for_section (symstrtab_hdr, off, true);
2080 elf_tdata (abfd)->next_file_pos = off;
2082 if (bfd_seek (abfd, symstrtab_hdr->sh_offset, SEEK_SET) != 0
2083 || ! _bfd_stringtab_emit (abfd, finfo.symstrtab))
2086 /* Adjust the relocs to have the correct symbol indices. */
2087 for (o = abfd->sections; o != NULL; o = o->next)
2089 struct elf_link_hash_entry **rel_hash;
2090 Elf_Internal_Shdr *rel_hdr;
2092 if ((o->flags & SEC_RELOC) == 0)
2095 rel_hash = elf_section_data (o)->rel_hashes;
2096 rel_hdr = &elf_section_data (o)->rel_hdr;
2097 for (i = 0; i < o->reloc_count; i++, rel_hash++)
2099 if (*rel_hash == NULL)
2102 BFD_ASSERT ((*rel_hash)->indx >= 0);
2104 if (rel_hdr->sh_entsize == sizeof (Elf_External_Rel))
2106 Elf_External_Rel *erel;
2107 Elf_Internal_Rel irel;
2109 erel = (Elf_External_Rel *) rel_hdr->contents + i;
2110 elf_swap_reloc_in (abfd, erel, &irel);
2111 irel.r_info = ELF_R_INFO ((*rel_hash)->indx,
2112 ELF_R_TYPE (irel.r_info));
2113 elf_swap_reloc_out (abfd, &irel, erel);
2117 Elf_External_Rela *erela;
2118 Elf_Internal_Rela irela;
2120 BFD_ASSERT (rel_hdr->sh_entsize
2121 == sizeof (Elf_External_Rela));
2123 erela = (Elf_External_Rela *) rel_hdr->contents + i;
2124 elf_swap_reloca_in (abfd, erela, &irela);
2125 irela.r_info = ELF_R_INFO ((*rel_hash)->indx,
2126 ELF_R_TYPE (irela.r_info));
2127 elf_swap_reloca_out (abfd, &irela, erela);
2131 /* Set the reloc_count field to 0 to prevent write_relocs from
2132 trying to swap the relocs out itself. */
2136 /* If we are linking against a dynamic object, or generating a
2137 shared library, finish up the dynamic linking information. */
2140 Elf_External_Dyn *dyncon, *dynconend;
2142 /* Fix up .dynamic entries. */
2143 o = bfd_get_section_by_name (dynobj, ".dynamic");
2144 BFD_ASSERT (o != NULL);
2146 dyncon = (Elf_External_Dyn *) o->contents;
2147 dynconend = (Elf_External_Dyn *) (o->contents + o->_raw_size);
2148 for (; dyncon < dynconend; dyncon++)
2150 Elf_Internal_Dyn dyn;
2154 elf_swap_dyn_in (dynobj, dyncon, &dyn);
2161 /* SVR4 linkers seem to set DT_INIT and DT_FINI based on
2162 magic _init and _fini symbols. This is pretty ugly,
2163 but we are compatible. */
2171 struct elf_link_hash_entry *h;
2173 h = elf_link_hash_lookup (elf_hash_table (info), name,
2174 false, false, true);
2176 && (h->root.type == bfd_link_hash_defined
2177 || h->root.type == bfd_link_hash_defweak))
2179 dyn.d_un.d_val = h->root.u.def.value;
2180 o = h->root.u.def.section;
2181 if (o->output_section != NULL)
2182 dyn.d_un.d_val += (o->output_section->vma
2183 + o->output_offset);
2186 /* The symbol is imported from another shared
2187 library and does not apply to this one. */
2191 elf_swap_dyn_out (dynobj, &dyn, dyncon);
2205 o = bfd_get_section_by_name (abfd, name);
2206 BFD_ASSERT (o != NULL);
2207 dyn.d_un.d_ptr = o->vma;
2208 elf_swap_dyn_out (dynobj, &dyn, dyncon);
2215 if (dyn.d_tag == DT_REL || dyn.d_tag == DT_RELSZ)
2220 for (i = 1; i < elf_elfheader (abfd)->e_shnum; i++)
2222 Elf_Internal_Shdr *hdr;
2224 hdr = elf_elfsections (abfd)[i];
2225 if (hdr->sh_type == type
2226 && (hdr->sh_flags & SHF_ALLOC) != 0)
2228 if (dyn.d_tag == DT_RELSZ || dyn.d_tag == DT_RELASZ)
2229 dyn.d_un.d_val += hdr->sh_size;
2232 if (dyn.d_un.d_val == 0
2233 || hdr->sh_addr < dyn.d_un.d_val)
2234 dyn.d_un.d_val = hdr->sh_addr;
2238 elf_swap_dyn_out (dynobj, &dyn, dyncon);
2244 /* If we have created any dynamic sections, then output them. */
2247 if (! (*bed->elf_backend_finish_dynamic_sections) (abfd, info))
2250 for (o = dynobj->sections; o != NULL; o = o->next)
2252 if ((o->flags & SEC_HAS_CONTENTS) == 0
2253 || o->_raw_size == 0)
2255 if ((o->flags & SEC_IN_MEMORY) == 0)
2257 /* At this point, we are only interested in sections
2258 created by elf_link_create_dynamic_sections. FIXME:
2259 This test is fragile. */
2262 if ((elf_section_data (o->output_section)->this_hdr.sh_type
2264 || strcmp (bfd_get_section_name (abfd, o), ".dynstr") != 0)
2266 if (! bfd_set_section_contents (abfd, o->output_section,
2267 o->contents, o->output_offset,
2275 /* The contents of the .dynstr section are actually in a
2277 off = elf_section_data (o->output_section)->this_hdr.sh_offset;
2278 if (bfd_seek (abfd, off, SEEK_SET) != 0
2279 || ! _bfd_stringtab_emit (abfd,
2280 elf_hash_table (info)->dynstr))
2286 if (finfo.symstrtab != NULL)
2287 _bfd_stringtab_free (finfo.symstrtab);
2288 if (finfo.contents != NULL)
2289 free (finfo.contents);
2290 if (finfo.external_relocs != NULL)
2291 free (finfo.external_relocs);
2292 if (finfo.internal_relocs != NULL)
2293 free (finfo.internal_relocs);
2294 if (finfo.external_syms != NULL)
2295 free (finfo.external_syms);
2296 if (finfo.internal_syms != NULL)
2297 free (finfo.internal_syms);
2298 if (finfo.indices != NULL)
2299 free (finfo.indices);
2300 if (finfo.sections != NULL)
2301 free (finfo.sections);
2302 if (finfo.symbuf != NULL)
2303 free (finfo.symbuf);
2304 for (o = abfd->sections; o != NULL; o = o->next)
2306 if ((o->flags & SEC_RELOC) != 0
2307 && elf_section_data (o)->rel_hashes != NULL)
2308 free (elf_section_data (o)->rel_hashes);
2311 elf_tdata (abfd)->linker = true;
2316 if (finfo.symstrtab != NULL)
2317 _bfd_stringtab_free (finfo.symstrtab);
2318 if (finfo.contents != NULL)
2319 free (finfo.contents);
2320 if (finfo.external_relocs != NULL)
2321 free (finfo.external_relocs);
2322 if (finfo.internal_relocs != NULL)
2323 free (finfo.internal_relocs);
2324 if (finfo.external_syms != NULL)
2325 free (finfo.external_syms);
2326 if (finfo.internal_syms != NULL)
2327 free (finfo.internal_syms);
2328 if (finfo.indices != NULL)
2329 free (finfo.indices);
2330 if (finfo.sections != NULL)
2331 free (finfo.sections);
2332 if (finfo.symbuf != NULL)
2333 free (finfo.symbuf);
2334 for (o = abfd->sections; o != NULL; o = o->next)
2336 if ((o->flags & SEC_RELOC) != 0
2337 && elf_section_data (o)->rel_hashes != NULL)
2338 free (elf_section_data (o)->rel_hashes);
2344 /* Add a symbol to the output symbol table. */
2347 elf_link_output_sym (finfo, name, elfsym, input_sec)
2348 struct elf_final_link_info *finfo;
2350 Elf_Internal_Sym *elfsym;
2351 asection *input_sec;
2353 boolean (*output_symbol_hook) PARAMS ((bfd *,
2354 struct bfd_link_info *info,
2359 output_symbol_hook = get_elf_backend_data (finfo->output_bfd)->
2360 elf_backend_link_output_symbol_hook;
2361 if (output_symbol_hook != NULL)
2363 if (! ((*output_symbol_hook)
2364 (finfo->output_bfd, finfo->info, name, elfsym, input_sec)))
2368 if (name == (const char *) NULL || *name == '\0')
2369 elfsym->st_name = 0;
2372 elfsym->st_name = (unsigned long) _bfd_stringtab_add (finfo->symstrtab,
2375 if (elfsym->st_name == (unsigned long) -1)
2379 if (finfo->symbuf_count >= finfo->symbuf_size)
2381 if (! elf_link_flush_output_syms (finfo))
2385 elf_swap_symbol_out (finfo->output_bfd, elfsym,
2386 (PTR) (finfo->symbuf + finfo->symbuf_count));
2387 ++finfo->symbuf_count;
2389 ++finfo->output_bfd->symcount;
2394 /* Flush the output symbols to the file. */
2397 elf_link_flush_output_syms (finfo)
2398 struct elf_final_link_info *finfo;
2400 Elf_Internal_Shdr *symtab;
2402 symtab = &elf_tdata (finfo->output_bfd)->symtab_hdr;
2404 if (bfd_seek (finfo->output_bfd, symtab->sh_offset + symtab->sh_size,
2406 || (bfd_write ((PTR) finfo->symbuf, finfo->symbuf_count,
2407 sizeof (Elf_External_Sym), finfo->output_bfd)
2408 != finfo->symbuf_count * sizeof (Elf_External_Sym)))
2411 symtab->sh_size += finfo->symbuf_count * sizeof (Elf_External_Sym);
2413 finfo->symbuf_count = 0;
2418 /* Add an external symbol to the symbol table. This is called from
2419 the hash table traversal routine. */
2422 elf_link_output_extsym (h, data)
2423 struct elf_link_hash_entry *h;
2426 struct elf_finfo_failed *eif = (struct elf_finfo_failed *) data;
2427 struct elf_final_link_info *finfo = eif->finfo;
2429 Elf_Internal_Sym sym;
2430 asection *input_sec;
2432 /* If we are not creating a shared library, and this symbol is
2433 referenced by a shared library but is not defined anywhere, then
2434 warn that it is undefined. If we do not do this, the runtime
2435 linker will complain that the symbol is undefined when the
2436 program is run. We don't have to worry about symbols that are
2437 referenced by regular files, because we will already have issued
2438 warnings for them. */
2439 if (! finfo->info->relocateable
2440 && ! finfo->info->shared
2441 && h->root.type == bfd_link_hash_undefined
2442 && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) != 0
2443 && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) == 0)
2445 if (! ((*finfo->info->callbacks->undefined_symbol)
2446 (finfo->info, h->root.root.string, h->root.u.undef.abfd,
2447 (asection *) NULL, 0)))
2454 /* We don't want to output symbols that have never been mentioned by
2455 a regular file, or that we have been told to strip. However, if
2456 h->indx is set to -2, the symbol is used by a reloc and we must
2460 else if (((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0
2461 || (h->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) != 0)
2462 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0
2463 && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) == 0)
2465 else if (finfo->info->strip == strip_all
2466 || (finfo->info->strip == strip_some
2467 && bfd_hash_lookup (finfo->info->keep_hash,
2468 h->root.root.string,
2469 false, false) == NULL))
2474 /* If we're stripping it, and it's not a dynamic symbol, there's
2475 nothing else to do. */
2476 if (strip && h->dynindx == -1)
2480 sym.st_size = h->size;
2482 if (h->root.type == bfd_link_hash_undefweak
2483 || h->root.type == bfd_link_hash_defweak)
2484 sym.st_info = ELF_ST_INFO (STB_WEAK, h->type);
2486 sym.st_info = ELF_ST_INFO (STB_GLOBAL, h->type);
2488 switch (h->root.type)
2491 case bfd_link_hash_new:
2495 case bfd_link_hash_undefined:
2496 input_sec = bfd_und_section_ptr;
2497 sym.st_shndx = SHN_UNDEF;
2500 case bfd_link_hash_undefweak:
2501 input_sec = bfd_und_section_ptr;
2502 sym.st_shndx = SHN_UNDEF;
2505 case bfd_link_hash_defined:
2506 case bfd_link_hash_defweak:
2508 input_sec = h->root.u.def.section;
2509 if (input_sec->output_section != NULL)
2512 _bfd_elf_section_from_bfd_section (finfo->output_bfd,
2513 input_sec->output_section);
2514 if (sym.st_shndx == (unsigned short) -1)
2520 /* ELF symbols in relocateable files are section relative,
2521 but in nonrelocateable files they are virtual
2523 sym.st_value = h->root.u.def.value + input_sec->output_offset;
2524 if (! finfo->info->relocateable)
2525 sym.st_value += input_sec->output_section->vma;
2529 BFD_ASSERT ((bfd_get_flavour (input_sec->owner)
2530 == bfd_target_elf_flavour)
2531 && elf_elfheader (input_sec->owner)->e_type == ET_DYN);
2532 sym.st_shndx = SHN_UNDEF;
2533 input_sec = bfd_und_section_ptr;
2538 case bfd_link_hash_common:
2539 input_sec = bfd_com_section_ptr;
2540 sym.st_shndx = SHN_COMMON;
2541 sym.st_value = 1 << h->root.u.c.p->alignment_power;
2544 case bfd_link_hash_indirect:
2545 case bfd_link_hash_warning:
2546 return (elf_link_output_extsym
2547 ((struct elf_link_hash_entry *) h->root.u.i.link, data));
2550 /* If this symbol should be put in the .dynsym section, then put it
2551 there now. We have already know the symbol index. We also fill
2552 in the entry in the .hash section. */
2553 if (h->dynindx != -1
2554 && elf_hash_table (finfo->info)->dynamic_sections_created)
2556 struct elf_backend_data *bed;
2559 bfd_byte *bucketpos;
2562 sym.st_name = h->dynstr_index;
2564 /* Give the processor backend a chance to tweak the symbol
2565 value, and also to finish up anything that needs to be done
2567 bed = get_elf_backend_data (finfo->output_bfd);
2568 if (! ((*bed->elf_backend_finish_dynamic_symbol)
2569 (finfo->output_bfd, finfo->info, h, &sym)))
2575 elf_swap_symbol_out (finfo->output_bfd, &sym,
2576 (PTR) (((Elf_External_Sym *)
2577 finfo->dynsym_sec->contents)
2580 bucketcount = elf_hash_table (finfo->info)->bucketcount;
2581 bucket = (bfd_elf_hash ((const unsigned char *) h->root.root.string)
2583 bucketpos = ((bfd_byte *) finfo->hash_sec->contents
2584 + (bucket + 2) * (ARCH_SIZE / 8));
2585 chain = get_word (finfo->output_bfd, bucketpos);
2586 put_word (finfo->output_bfd, h->dynindx, bucketpos);
2587 put_word (finfo->output_bfd, chain,
2588 ((bfd_byte *) finfo->hash_sec->contents
2589 + (bucketcount + 2 + h->dynindx) * (ARCH_SIZE / 8)));
2592 /* If we're stripping it, then it was just a dynamic symbol, and
2593 there's nothing else to do. */
2597 h->indx = finfo->output_bfd->symcount;
2599 if (! elf_link_output_sym (finfo, h->root.root.string, &sym, input_sec))
2608 /* Link an input file into the linker output file. This function
2609 handles all the sections and relocations of the input file at once.
2610 This is so that we only have to read the local symbols once, and
2611 don't have to keep them in memory. */
2614 elf_link_input_bfd (finfo, input_bfd)
2615 struct elf_final_link_info *finfo;
2618 boolean (*relocate_section) PARAMS ((bfd *, struct bfd_link_info *,
2619 bfd *, asection *, bfd_byte *,
2620 Elf_Internal_Rela *,
2621 Elf_Internal_Sym *, asection **));
2623 Elf_Internal_Shdr *symtab_hdr;
2626 Elf_External_Sym *esym;
2627 Elf_External_Sym *esymend;
2628 Elf_Internal_Sym *isym;
2630 asection **ppsection;
2633 output_bfd = finfo->output_bfd;
2635 get_elf_backend_data (output_bfd)->elf_backend_relocate_section;
2637 /* If this is a dynamic object, we don't want to do anything here:
2638 we don't want the local symbols, and we don't want the section
2640 if (elf_elfheader (input_bfd)->e_type == ET_DYN)
2643 symtab_hdr = &elf_tdata (input_bfd)->symtab_hdr;
2644 if (elf_bad_symtab (input_bfd))
2646 locsymcount = symtab_hdr->sh_size / sizeof (Elf_External_Sym);
2651 locsymcount = symtab_hdr->sh_info;
2652 extsymoff = symtab_hdr->sh_info;
2655 /* Read the local symbols. */
2657 && (bfd_seek (input_bfd, symtab_hdr->sh_offset, SEEK_SET) != 0
2658 || (bfd_read (finfo->external_syms, sizeof (Elf_External_Sym),
2659 locsymcount, input_bfd)
2660 != locsymcount * sizeof (Elf_External_Sym))))
2663 /* Swap in the local symbols and write out the ones which we know
2664 are going into the output file. */
2665 esym = finfo->external_syms;
2666 esymend = esym + locsymcount;
2667 isym = finfo->internal_syms;
2668 pindex = finfo->indices;
2669 ppsection = finfo->sections;
2670 for (; esym < esymend; esym++, isym++, pindex++, ppsection++)
2674 Elf_Internal_Sym osym;
2676 elf_swap_symbol_in (input_bfd, esym, isym);
2679 if (elf_bad_symtab (input_bfd))
2681 if (ELF_ST_BIND (isym->st_info) != STB_LOCAL)
2688 if (isym->st_shndx == SHN_UNDEF)
2689 isec = bfd_und_section_ptr;
2690 else if (isym->st_shndx > 0 && isym->st_shndx < SHN_LORESERVE)
2691 isec = section_from_elf_index (input_bfd, isym->st_shndx);
2692 else if (isym->st_shndx == SHN_ABS)
2693 isec = bfd_abs_section_ptr;
2694 else if (isym->st_shndx == SHN_COMMON)
2695 isec = bfd_com_section_ptr;
2704 /* Don't output the first, undefined, symbol. */
2705 if (esym == finfo->external_syms)
2708 /* If we are stripping all symbols, we don't want to output this
2710 if (finfo->info->strip == strip_all)
2713 /* We never output section symbols. Instead, we use the section
2714 symbol of the corresponding section in the output file. */
2715 if (ELF_ST_TYPE (isym->st_info) == STT_SECTION)
2718 /* If we are discarding all local symbols, we don't want to
2719 output this one. If we are generating a relocateable output
2720 file, then some of the local symbols may be required by
2721 relocs; we output them below as we discover that they are
2723 if (finfo->info->discard == discard_all)
2726 /* Get the name of the symbol. */
2727 name = bfd_elf_string_from_elf_section (input_bfd, symtab_hdr->sh_link,
2732 /* See if we are discarding symbols with this name. */
2733 if ((finfo->info->strip == strip_some
2734 && (bfd_hash_lookup (finfo->info->keep_hash, name, false, false)
2736 || (finfo->info->discard == discard_l
2737 && strncmp (name, finfo->info->lprefix,
2738 finfo->info->lprefix_len) == 0))
2741 /* If we get here, we are going to output this symbol. */
2745 /* Adjust the section index for the output file. */
2746 osym.st_shndx = _bfd_elf_section_from_bfd_section (output_bfd,
2747 isec->output_section);
2748 if (osym.st_shndx == (unsigned short) -1)
2751 *pindex = output_bfd->symcount;
2753 /* ELF symbols in relocateable files are section relative, but
2754 in executable files they are virtual addresses. Note that
2755 this code assumes that all ELF sections have an associated
2756 BFD section with a reasonable value for output_offset; below
2757 we assume that they also have a reasonable value for
2758 output_section. Any special sections must be set up to meet
2759 these requirements. */
2760 osym.st_value += isec->output_offset;
2761 if (! finfo->info->relocateable)
2762 osym.st_value += isec->output_section->vma;
2764 if (! elf_link_output_sym (finfo, name, &osym, isec))
2768 /* Relocate the contents of each section. */
2769 for (o = input_bfd->sections; o != NULL; o = o->next)
2771 if ((o->flags & SEC_HAS_CONTENTS) == 0)
2774 if ((o->flags & SEC_IN_MEMORY) != 0
2775 && input_bfd == elf_hash_table (finfo->info)->dynobj)
2777 /* Section was created by elf_link_create_dynamic_sections.
2778 FIXME: This test is fragile. */
2782 /* Read the contents of the section. */
2783 if (! bfd_get_section_contents (input_bfd, o, finfo->contents,
2784 (file_ptr) 0, o->_raw_size))
2787 if ((o->flags & SEC_RELOC) != 0)
2789 Elf_Internal_Rela *internal_relocs;
2791 /* Get the swapped relocs. */
2792 internal_relocs = elf_link_read_relocs (input_bfd, o,
2793 finfo->external_relocs,
2794 finfo->internal_relocs,
2796 if (internal_relocs == NULL
2797 && o->reloc_count > 0)
2800 /* Relocate the section by invoking a back end routine.
2802 The back end routine is responsible for adjusting the
2803 section contents as necessary, and (if using Rela relocs
2804 and generating a relocateable output file) adjusting the
2805 reloc addend as necessary.
2807 The back end routine does not have to worry about setting
2808 the reloc address or the reloc symbol index.
2810 The back end routine is given a pointer to the swapped in
2811 internal symbols, and can access the hash table entries
2812 for the external symbols via elf_sym_hashes (input_bfd).
2814 When generating relocateable output, the back end routine
2815 must handle STB_LOCAL/STT_SECTION symbols specially. The
2816 output symbol is going to be a section symbol
2817 corresponding to the output section, which will require
2818 the addend to be adjusted. */
2820 if (! (*relocate_section) (output_bfd, finfo->info,
2824 finfo->internal_syms,
2828 if (finfo->info->relocateable)
2830 Elf_Internal_Rela *irela;
2831 Elf_Internal_Rela *irelaend;
2832 struct elf_link_hash_entry **rel_hash;
2833 Elf_Internal_Shdr *input_rel_hdr;
2834 Elf_Internal_Shdr *output_rel_hdr;
2836 /* Adjust the reloc addresses and symbol indices. */
2838 irela = internal_relocs;
2839 irelaend = irela + o->reloc_count;
2840 rel_hash = (elf_section_data (o->output_section)->rel_hashes
2841 + o->output_section->reloc_count);
2842 for (; irela < irelaend; irela++, rel_hash++)
2844 unsigned long r_symndx;
2845 Elf_Internal_Sym *isym;
2848 irela->r_offset += o->output_offset;
2850 r_symndx = ELF_R_SYM (irela->r_info);
2855 if (r_symndx >= locsymcount
2856 || (elf_bad_symtab (input_bfd)
2857 && finfo->sections[r_symndx] == NULL))
2861 /* This is a reloc against a global symbol. We
2862 have not yet output all the local symbols, so
2863 we do not know the symbol index of any global
2864 symbol. We set the rel_hash entry for this
2865 reloc to point to the global hash table entry
2866 for this symbol. The symbol index is then
2867 set at the end of elf_bfd_final_link. */
2868 indx = r_symndx - extsymoff;
2869 *rel_hash = elf_sym_hashes (input_bfd)[indx];
2871 /* Setting the index to -2 tells
2872 elf_link_output_extsym that this symbol is
2874 BFD_ASSERT ((*rel_hash)->indx < 0);
2875 (*rel_hash)->indx = -2;
2880 /* This is a reloc against a local symbol. */
2883 isym = finfo->internal_syms + r_symndx;
2884 sec = finfo->sections[r_symndx];
2885 if (ELF_ST_TYPE (isym->st_info) == STT_SECTION)
2887 /* I suppose the backend ought to fill in the
2888 section of any STT_SECTION symbol against a
2889 processor specific section. */
2890 if (sec != NULL && bfd_is_abs_section (sec))
2892 else if (sec == NULL || sec->owner == NULL)
2894 bfd_set_error (bfd_error_bad_value);
2899 r_symndx = sec->output_section->target_index;
2900 BFD_ASSERT (r_symndx != 0);
2905 if (finfo->indices[r_symndx] == -1)
2911 if (finfo->info->strip == strip_all)
2913 /* You can't do ld -r -s. */
2914 bfd_set_error (bfd_error_invalid_operation);
2918 /* This symbol was skipped earlier, but
2919 since it is needed by a reloc, we
2920 must output it now. */
2921 link = symtab_hdr->sh_link;
2922 name = bfd_elf_string_from_elf_section (input_bfd,
2928 osec = sec->output_section;
2930 _bfd_elf_section_from_bfd_section (output_bfd,
2932 if (isym->st_shndx == (unsigned short) -1)
2935 isym->st_value += sec->output_offset;
2936 if (! finfo->info->relocateable)
2937 isym->st_value += osec->vma;
2939 finfo->indices[r_symndx] = output_bfd->symcount;
2941 if (! elf_link_output_sym (finfo, name, isym, sec))
2945 r_symndx = finfo->indices[r_symndx];
2948 irela->r_info = ELF_R_INFO (r_symndx,
2949 ELF_R_TYPE (irela->r_info));
2952 /* Swap out the relocs. */
2953 input_rel_hdr = &elf_section_data (o)->rel_hdr;
2954 output_rel_hdr = &elf_section_data (o->output_section)->rel_hdr;
2955 BFD_ASSERT (output_rel_hdr->sh_entsize
2956 == input_rel_hdr->sh_entsize);
2957 irela = internal_relocs;
2958 irelaend = irela + o->reloc_count;
2959 if (input_rel_hdr->sh_entsize == sizeof (Elf_External_Rel))
2961 Elf_External_Rel *erel;
2963 erel = ((Elf_External_Rel *) output_rel_hdr->contents
2964 + o->output_section->reloc_count);
2965 for (; irela < irelaend; irela++, erel++)
2967 Elf_Internal_Rel irel;
2969 irel.r_offset = irela->r_offset;
2970 irel.r_info = irela->r_info;
2971 BFD_ASSERT (irela->r_addend == 0);
2972 elf_swap_reloc_out (output_bfd, &irel, erel);
2977 Elf_External_Rela *erela;
2979 BFD_ASSERT (input_rel_hdr->sh_entsize
2980 == sizeof (Elf_External_Rela));
2981 erela = ((Elf_External_Rela *) output_rel_hdr->contents
2982 + o->output_section->reloc_count);
2983 for (; irela < irelaend; irela++, erela++)
2984 elf_swap_reloca_out (output_bfd, irela, erela);
2987 o->output_section->reloc_count += o->reloc_count;
2991 /* Write out the modified section contents. */
2992 if (! bfd_set_section_contents (output_bfd, o->output_section,
2993 finfo->contents, o->output_offset,
2994 (o->_cooked_size != 0
3003 /* Generate a reloc when linking an ELF file. This is a reloc
3004 requested by the linker, and does come from any input file. This
3005 is used to build constructor and destructor tables when linking
3009 elf_reloc_link_order (output_bfd, info, output_section, link_order)
3011 struct bfd_link_info *info;
3012 asection *output_section;
3013 struct bfd_link_order *link_order;
3015 reloc_howto_type *howto;
3018 struct elf_link_hash_entry **rel_hash_ptr;
3019 Elf_Internal_Shdr *rel_hdr;
3021 howto = bfd_reloc_type_lookup (output_bfd, link_order->u.reloc.p->reloc);
3024 bfd_set_error (bfd_error_bad_value);
3028 /* If this is an inplace reloc, we must write the addend into the
3030 if (howto->partial_inplace
3031 && link_order->u.reloc.p->addend != 0)
3034 bfd_reloc_status_type rstat;
3038 size = bfd_get_reloc_size (howto);
3039 buf = (bfd_byte *) bfd_zmalloc (size);
3040 if (buf == (bfd_byte *) NULL)
3042 bfd_set_error (bfd_error_no_memory);
3045 rstat = _bfd_relocate_contents (howto, output_bfd,
3046 link_order->u.reloc.p->addend, buf);
3052 case bfd_reloc_outofrange:
3054 case bfd_reloc_overflow:
3055 if (! ((*info->callbacks->reloc_overflow)
3057 (link_order->type == bfd_section_reloc_link_order
3058 ? bfd_section_name (output_bfd,
3059 link_order->u.reloc.p->u.section)
3060 : link_order->u.reloc.p->u.name),
3061 howto->name, link_order->u.reloc.p->addend,
3062 (bfd *) NULL, (asection *) NULL, (bfd_vma) 0)))
3069 ok = bfd_set_section_contents (output_bfd, output_section, (PTR) buf,
3070 (file_ptr) link_order->offset, size);
3076 /* Figure out the symbol index. */
3077 rel_hash_ptr = (elf_section_data (output_section)->rel_hashes
3078 + output_section->reloc_count);
3079 if (link_order->type == bfd_section_reloc_link_order)
3081 indx = link_order->u.reloc.p->u.section->target_index;
3082 BFD_ASSERT (indx != 0);
3083 *rel_hash_ptr = NULL;
3087 struct elf_link_hash_entry *h;
3089 h = elf_link_hash_lookup (elf_hash_table (info),
3090 link_order->u.reloc.p->u.name,
3091 false, false, true);
3094 /* Setting the index to -2 tells elf_link_output_extsym that
3095 this symbol is used by a reloc. */
3102 if (! ((*info->callbacks->unattached_reloc)
3103 (info, link_order->u.reloc.p->u.name, (bfd *) NULL,
3104 (asection *) NULL, (bfd_vma) 0)))
3110 /* The address of a reloc is relative to the section in a
3111 relocateable file, and is a virtual address in an executable
3113 offset = link_order->offset;
3114 if (! info->relocateable)
3115 offset += output_section->vma;
3117 rel_hdr = &elf_section_data (output_section)->rel_hdr;
3119 if (rel_hdr->sh_type == SHT_REL)
3121 Elf_Internal_Rel irel;
3122 Elf_External_Rel *erel;
3124 irel.r_offset = offset;
3125 irel.r_info = ELF_R_INFO (indx, howto->type);
3126 erel = ((Elf_External_Rel *) rel_hdr->contents
3127 + output_section->reloc_count);
3128 elf_swap_reloc_out (output_bfd, &irel, erel);
3132 Elf_Internal_Rela irela;
3133 Elf_External_Rela *erela;
3135 irela.r_offset = offset;
3136 irela.r_info = ELF_R_INFO (indx, howto->type);
3137 irela.r_addend = link_order->u.reloc.p->addend;
3138 erela = ((Elf_External_Rela *) rel_hdr->contents
3139 + output_section->reloc_count);
3140 elf_swap_reloca_out (output_bfd, &irela, erela);
3143 ++output_section->reloc_count;