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[binutils-gdb.git] / bfd / elflink.h
1 /* ELF linker support.
2 Copyright 1995, 1996 Free Software Foundation, Inc.
3
4 This file is part of BFD, the Binary File Descriptor library.
5
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.
10
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.
15
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. */
19
20 /* ELF linker code. */
21
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));
32
33 /* This struct is used to pass information to routines called via
34 elf_link_hash_traverse which must return failure. */
35
36 struct elf_info_failed
37 {
38 boolean failed;
39 struct bfd_link_info *info;
40 };
41
42 /* Given an ELF BFD, add symbols to the global hash table as
43 appropriate. */
44
45 boolean
46 elf_bfd_link_add_symbols (abfd, info)
47 bfd *abfd;
48 struct bfd_link_info *info;
49 {
50 switch (bfd_get_format (abfd))
51 {
52 case bfd_object:
53 return elf_link_add_object_symbols (abfd, info);
54 case bfd_archive:
55 return elf_link_add_archive_symbols (abfd, info);
56 default:
57 bfd_set_error (bfd_error_wrong_format);
58 return false;
59 }
60 }
61
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.
77
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
82 object file.
83
84 Unfortunately, we do have to make multiple passes over the symbol
85 table until nothing further is resolved. */
86
87 static boolean
88 elf_link_add_archive_symbols (abfd, info)
89 bfd *abfd;
90 struct bfd_link_info *info;
91 {
92 symindex c;
93 boolean *defined = NULL;
94 boolean *included = NULL;
95 carsym *symdefs;
96 boolean loop;
97
98 if (! bfd_has_map (abfd))
99 {
100 /* An empty archive is a special case. */
101 if (bfd_openr_next_archived_file (abfd, (bfd *) NULL) == NULL)
102 return true;
103 bfd_set_error (bfd_error_no_armap);
104 return false;
105 }
106
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;
111 if (c == 0)
112 return true;
113 defined = (boolean *) bfd_malloc (c * sizeof (boolean));
114 included = (boolean *) bfd_malloc (c * sizeof (boolean));
115 if (defined == (boolean *) NULL || included == (boolean *) NULL)
116 goto error_return;
117 memset (defined, 0, c * sizeof (boolean));
118 memset (included, 0, c * sizeof (boolean));
119
120 symdefs = bfd_ardata (abfd)->symdefs;
121
122 do
123 {
124 file_ptr last;
125 symindex i;
126 carsym *symdef;
127 carsym *symdefend;
128
129 loop = false;
130 last = -1;
131
132 symdef = symdefs;
133 symdefend = symdef + c;
134 for (i = 0; symdef < symdefend; symdef++, i++)
135 {
136 struct elf_link_hash_entry *h;
137 bfd *element;
138 struct bfd_link_hash_entry *undefs_tail;
139 symindex mark;
140
141 if (defined[i] || included[i])
142 continue;
143 if (symdef->file_offset == last)
144 {
145 included[i] = true;
146 continue;
147 }
148
149 h = elf_link_hash_lookup (elf_hash_table (info), symdef->name,
150 false, false, false);
151 if (h == (struct elf_link_hash_entry *) NULL)
152 continue;
153 if (h->root.type != bfd_link_hash_undefined)
154 {
155 if (h->root.type != bfd_link_hash_undefweak)
156 defined[i] = true;
157 continue;
158 }
159
160 /* We need to include this archive member. */
161
162 element = _bfd_get_elt_at_filepos (abfd, symdef->file_offset);
163 if (element == (bfd *) NULL)
164 goto error_return;
165
166 if (! bfd_check_format (element, bfd_object))
167 goto error_return;
168
169 /* Doublecheck that we have not included this object
170 already--it should be impossible, but there may be
171 something wrong with the archive. */
172 if (element->archive_pass != 0)
173 {
174 bfd_set_error (bfd_error_bad_value);
175 goto error_return;
176 }
177 element->archive_pass = 1;
178
179 undefs_tail = info->hash->undefs_tail;
180
181 if (! (*info->callbacks->add_archive_element) (info, element,
182 symdef->name))
183 goto error_return;
184 if (! elf_link_add_object_symbols (element, info))
185 goto error_return;
186
187 /* If there are any new undefined symbols, we need to make
188 another pass through the archive in order to see whether
189 they can be defined. FIXME: This isn't perfect, because
190 common symbols wind up on undefs_tail and because an
191 undefined symbol which is defined later on in this pass
192 does not require another pass. This isn't a bug, but it
193 does make the code less efficient than it could be. */
194 if (undefs_tail != info->hash->undefs_tail)
195 loop = true;
196
197 /* Look backward to mark all symbols from this object file
198 which we have already seen in this pass. */
199 mark = i;
200 do
201 {
202 included[mark] = true;
203 if (mark == 0)
204 break;
205 --mark;
206 }
207 while (symdefs[mark].file_offset == symdef->file_offset);
208
209 /* We mark subsequent symbols from this object file as we go
210 on through the loop. */
211 last = symdef->file_offset;
212 }
213 }
214 while (loop);
215
216 free (defined);
217 free (included);
218
219 return true;
220
221 error_return:
222 if (defined != (boolean *) NULL)
223 free (defined);
224 if (included != (boolean *) NULL)
225 free (included);
226 return false;
227 }
228
229 /* Add symbols from an ELF object file to the linker hash table. */
230
231 static boolean
232 elf_link_add_object_symbols (abfd, info)
233 bfd *abfd;
234 struct bfd_link_info *info;
235 {
236 boolean (*add_symbol_hook) PARAMS ((bfd *, struct bfd_link_info *,
237 const Elf_Internal_Sym *,
238 const char **, flagword *,
239 asection **, bfd_vma *));
240 boolean (*check_relocs) PARAMS ((bfd *, struct bfd_link_info *,
241 asection *, const Elf_Internal_Rela *));
242 boolean collect;
243 Elf_Internal_Shdr *hdr;
244 size_t symcount;
245 size_t extsymcount;
246 size_t extsymoff;
247 Elf_External_Sym *buf = NULL;
248 struct elf_link_hash_entry **sym_hash;
249 boolean dynamic;
250 Elf_External_Dyn *dynbuf = NULL;
251 struct elf_link_hash_entry *weaks;
252 Elf_External_Sym *esym;
253 Elf_External_Sym *esymend;
254
255 add_symbol_hook = get_elf_backend_data (abfd)->elf_add_symbol_hook;
256 collect = get_elf_backend_data (abfd)->collect;
257
258 /* As a GNU extension, any input sections which are named
259 .gnu.warning.SYMBOL are treated as warning symbols for the given
260 symbol. This differs from .gnu.warning sections, which generate
261 warnings when they are included in an output file. */
262 if (! info->shared)
263 {
264 asection *s;
265
266 for (s = abfd->sections; s != NULL; s = s->next)
267 {
268 const char *name;
269
270 name = bfd_get_section_name (abfd, s);
271 if (strncmp (name, ".gnu.warning.", sizeof ".gnu.warning." - 1) == 0)
272 {
273 char *msg;
274 bfd_size_type sz;
275
276 sz = bfd_section_size (abfd, s);
277 msg = (char *) bfd_alloc (abfd, sz);
278 if (msg == NULL)
279 goto error_return;
280
281 if (! bfd_get_section_contents (abfd, s, msg, (file_ptr) 0, sz))
282 goto error_return;
283
284 if (! (_bfd_generic_link_add_one_symbol
285 (info, abfd,
286 name + sizeof ".gnu.warning." - 1,
287 BSF_WARNING, s, (bfd_vma) 0, msg, false, collect,
288 (struct bfd_link_hash_entry **) NULL)))
289 goto error_return;
290
291 if (! info->relocateable)
292 {
293 /* Clobber the section size so that the warning does
294 not get copied into the output file. */
295 s->_raw_size = 0;
296 }
297 }
298 }
299 }
300
301 /* A stripped shared library might only have a dynamic symbol table,
302 not a regular symbol table. In that case we can still go ahead
303 and link using the dynamic symbol table. */
304 if (elf_onesymtab (abfd) == 0
305 && elf_dynsymtab (abfd) != 0)
306 {
307 elf_onesymtab (abfd) = elf_dynsymtab (abfd);
308 elf_tdata (abfd)->symtab_hdr = elf_tdata (abfd)->dynsymtab_hdr;
309 }
310
311 hdr = &elf_tdata (abfd)->symtab_hdr;
312 symcount = hdr->sh_size / sizeof (Elf_External_Sym);
313
314 /* The sh_info field of the symtab header tells us where the
315 external symbols start. We don't care about the local symbols at
316 this point. */
317 if (elf_bad_symtab (abfd))
318 {
319 extsymcount = symcount;
320 extsymoff = 0;
321 }
322 else
323 {
324 extsymcount = symcount - hdr->sh_info;
325 extsymoff = hdr->sh_info;
326 }
327
328 buf = ((Elf_External_Sym *)
329 bfd_malloc (extsymcount * sizeof (Elf_External_Sym)));
330 if (buf == NULL && extsymcount != 0)
331 goto error_return;
332
333 /* We store a pointer to the hash table entry for each external
334 symbol. */
335 sym_hash = ((struct elf_link_hash_entry **)
336 bfd_alloc (abfd,
337 extsymcount * sizeof (struct elf_link_hash_entry *)));
338 if (sym_hash == NULL)
339 goto error_return;
340 elf_sym_hashes (abfd) = sym_hash;
341
342 if (elf_elfheader (abfd)->e_type != ET_DYN)
343 {
344 dynamic = false;
345
346 /* If we are creating a shared library, create all the dynamic
347 sections immediately. We need to attach them to something,
348 so we attach them to this BFD, provided it is the right
349 format. FIXME: If there are no input BFD's of the same
350 format as the output, we can't make a shared library. */
351 if (info->shared
352 && ! elf_hash_table (info)->dynamic_sections_created
353 && abfd->xvec == info->hash->creator)
354 {
355 if (! elf_link_create_dynamic_sections (abfd, info))
356 goto error_return;
357 }
358 }
359 else
360 {
361 asection *s;
362 boolean add_needed;
363 const char *name;
364 bfd_size_type oldsize;
365 bfd_size_type strindex;
366
367 dynamic = true;
368
369 /* You can't use -r against a dynamic object. Also, there's no
370 hope of using a dynamic object which does not exactly match
371 the format of the output file. */
372 if (info->relocateable
373 || info->hash->creator != abfd->xvec)
374 {
375 bfd_set_error (bfd_error_invalid_operation);
376 goto error_return;
377 }
378
379 /* Find the name to use in a DT_NEEDED entry that refers to this
380 object. If the object has a DT_SONAME entry, we use it.
381 Otherwise, if the generic linker stuck something in
382 elf_dt_needed_name, we use that. Otherwise, we just use the
383 file name. If the generic linker put a null string into
384 elf_dt_needed_name, we don't make a DT_NEEDED entry at all,
385 even if there is a DT_SONAME entry. */
386 add_needed = true;
387 name = bfd_get_filename (abfd);
388 if (elf_dt_needed_name (abfd) != NULL)
389 {
390 name = elf_dt_needed_name (abfd);
391 if (*name == '\0')
392 add_needed = false;
393 }
394 s = bfd_get_section_by_name (abfd, ".dynamic");
395 if (s != NULL)
396 {
397 Elf_External_Dyn *extdyn;
398 Elf_External_Dyn *extdynend;
399 int elfsec;
400 unsigned long link;
401
402 dynbuf = (Elf_External_Dyn *) bfd_malloc ((size_t) s->_raw_size);
403 if (dynbuf == NULL)
404 goto error_return;
405
406 if (! bfd_get_section_contents (abfd, s, (PTR) dynbuf,
407 (file_ptr) 0, s->_raw_size))
408 goto error_return;
409
410 elfsec = _bfd_elf_section_from_bfd_section (abfd, s);
411 if (elfsec == -1)
412 goto error_return;
413 link = elf_elfsections (abfd)[elfsec]->sh_link;
414
415 extdyn = dynbuf;
416 extdynend = extdyn + s->_raw_size / sizeof (Elf_External_Dyn);
417 for (; extdyn < extdynend; extdyn++)
418 {
419 Elf_Internal_Dyn dyn;
420
421 elf_swap_dyn_in (abfd, extdyn, &dyn);
422 if (add_needed && dyn.d_tag == DT_SONAME)
423 {
424 name = bfd_elf_string_from_elf_section (abfd, link,
425 dyn.d_un.d_val);
426 if (name == NULL)
427 goto error_return;
428 }
429 if (dyn.d_tag == DT_NEEDED)
430 {
431 struct bfd_link_needed_list *n, **pn;
432 char *fnm, *anm;
433
434 n = ((struct bfd_link_needed_list *)
435 bfd_alloc (abfd, sizeof (struct bfd_link_needed_list)));
436 fnm = bfd_elf_string_from_elf_section (abfd, link,
437 dyn.d_un.d_val);
438 if (n == NULL || fnm == NULL)
439 goto error_return;
440 anm = bfd_alloc (abfd, strlen (fnm) + 1);
441 if (anm == NULL)
442 goto error_return;
443 strcpy (anm, fnm);
444 n->name = anm;
445 n->by = abfd;
446 n->next = NULL;
447 for (pn = &elf_hash_table (info)->needed;
448 *pn != NULL;
449 pn = &(*pn)->next)
450 ;
451 *pn = n;
452 }
453 }
454
455 free (dynbuf);
456 dynbuf = NULL;
457 }
458
459 /* We do not want to include any of the sections in a dynamic
460 object in the output file. We hack by simply clobbering the
461 list of sections in the BFD. This could be handled more
462 cleanly by, say, a new section flag; the existing
463 SEC_NEVER_LOAD flag is not the one we want, because that one
464 still implies that the section takes up space in the output
465 file. */
466 abfd->sections = NULL;
467 abfd->section_count = 0;
468
469 /* If this is the first dynamic object found in the link, create
470 the special sections required for dynamic linking. */
471 if (! elf_hash_table (info)->dynamic_sections_created)
472 {
473 if (! elf_link_create_dynamic_sections (abfd, info))
474 goto error_return;
475 }
476
477 if (add_needed)
478 {
479 /* Add a DT_NEEDED entry for this dynamic object. */
480 oldsize = _bfd_stringtab_size (elf_hash_table (info)->dynstr);
481 strindex = _bfd_stringtab_add (elf_hash_table (info)->dynstr, name,
482 true, false);
483 if (strindex == (bfd_size_type) -1)
484 goto error_return;
485
486 if (oldsize == _bfd_stringtab_size (elf_hash_table (info)->dynstr))
487 {
488 asection *sdyn;
489 Elf_External_Dyn *dyncon, *dynconend;
490
491 /* The hash table size did not change, which means that
492 the dynamic object name was already entered. If we
493 have already included this dynamic object in the
494 link, just ignore it. There is no reason to include
495 a particular dynamic object more than once. */
496 sdyn = bfd_get_section_by_name (elf_hash_table (info)->dynobj,
497 ".dynamic");
498 BFD_ASSERT (sdyn != NULL);
499
500 dyncon = (Elf_External_Dyn *) sdyn->contents;
501 dynconend = (Elf_External_Dyn *) (sdyn->contents +
502 sdyn->_raw_size);
503 for (; dyncon < dynconend; dyncon++)
504 {
505 Elf_Internal_Dyn dyn;
506
507 elf_swap_dyn_in (elf_hash_table (info)->dynobj, dyncon,
508 &dyn);
509 if (dyn.d_tag == DT_NEEDED
510 && dyn.d_un.d_val == strindex)
511 {
512 if (buf != NULL)
513 free (buf);
514 return true;
515 }
516 }
517 }
518
519 if (! elf_add_dynamic_entry (info, DT_NEEDED, strindex))
520 goto error_return;
521 }
522 }
523
524 if (bfd_seek (abfd,
525 hdr->sh_offset + extsymoff * sizeof (Elf_External_Sym),
526 SEEK_SET) != 0
527 || (bfd_read ((PTR) buf, sizeof (Elf_External_Sym), extsymcount, abfd)
528 != extsymcount * sizeof (Elf_External_Sym)))
529 goto error_return;
530
531 weaks = NULL;
532
533 esymend = buf + extsymcount;
534 for (esym = buf; esym < esymend; esym++, sym_hash++)
535 {
536 Elf_Internal_Sym sym;
537 int bind;
538 bfd_vma value;
539 asection *sec;
540 flagword flags;
541 const char *name;
542 struct elf_link_hash_entry *h;
543 boolean definition;
544 boolean size_change_ok, type_change_ok;
545 boolean new_weakdef;
546
547 elf_swap_symbol_in (abfd, esym, &sym);
548
549 flags = BSF_NO_FLAGS;
550 sec = NULL;
551 value = sym.st_value;
552 *sym_hash = NULL;
553
554 bind = ELF_ST_BIND (sym.st_info);
555 if (bind == STB_LOCAL)
556 {
557 /* This should be impossible, since ELF requires that all
558 global symbols follow all local symbols, and that sh_info
559 point to the first global symbol. Unfortunatealy, Irix 5
560 screws this up. */
561 continue;
562 }
563 else if (bind == STB_GLOBAL)
564 {
565 if (sym.st_shndx != SHN_UNDEF
566 && sym.st_shndx != SHN_COMMON)
567 flags = BSF_GLOBAL;
568 else
569 flags = 0;
570 }
571 else if (bind == STB_WEAK)
572 flags = BSF_WEAK;
573 else
574 {
575 /* Leave it up to the processor backend. */
576 }
577
578 if (sym.st_shndx == SHN_UNDEF)
579 sec = bfd_und_section_ptr;
580 else if (sym.st_shndx > 0 && sym.st_shndx < SHN_LORESERVE)
581 {
582 sec = section_from_elf_index (abfd, sym.st_shndx);
583 if (sec != NULL)
584 value -= sec->vma;
585 else
586 sec = bfd_abs_section_ptr;
587 }
588 else if (sym.st_shndx == SHN_ABS)
589 sec = bfd_abs_section_ptr;
590 else if (sym.st_shndx == SHN_COMMON)
591 {
592 sec = bfd_com_section_ptr;
593 /* What ELF calls the size we call the value. What ELF
594 calls the value we call the alignment. */
595 value = sym.st_size;
596 }
597 else
598 {
599 /* Leave it up to the processor backend. */
600 }
601
602 name = bfd_elf_string_from_elf_section (abfd, hdr->sh_link, sym.st_name);
603 if (name == (const char *) NULL)
604 goto error_return;
605
606 if (add_symbol_hook)
607 {
608 if (! (*add_symbol_hook) (abfd, info, &sym, &name, &flags, &sec,
609 &value))
610 goto error_return;
611
612 /* The hook function sets the name to NULL if this symbol
613 should be skipped for some reason. */
614 if (name == (const char *) NULL)
615 continue;
616 }
617
618 /* Sanity check that all possibilities were handled. */
619 if (sec == (asection *) NULL)
620 {
621 bfd_set_error (bfd_error_bad_value);
622 goto error_return;
623 }
624
625 if (bfd_is_und_section (sec)
626 || bfd_is_com_section (sec))
627 definition = false;
628 else
629 definition = true;
630
631 size_change_ok = false;
632 type_change_ok = get_elf_backend_data (abfd)->type_change_ok;
633 if (info->hash->creator->flavour == bfd_target_elf_flavour)
634 {
635 /* We need to look up the symbol now in order to get some of
636 the dynamic object handling right. We pass the hash
637 table entry in to _bfd_generic_link_add_one_symbol so
638 that it does not have to look it up again. */
639 h = elf_link_hash_lookup (elf_hash_table (info), name,
640 true, false, false);
641 if (h == NULL)
642 goto error_return;
643 *sym_hash = h;
644
645 while (h->root.type == bfd_link_hash_indirect
646 || h->root.type == bfd_link_hash_warning)
647 h = (struct elf_link_hash_entry *) h->root.u.i.link;
648
649 /* It's OK to change the type if it used to be a weak
650 definition. */
651 if (h->root.type == bfd_link_hash_defweak
652 || h->root.type == bfd_link_hash_undefweak)
653 type_change_ok = true;
654
655 /* It's OK to change the size if it used to be a weak
656 definition, or if it used to be undefined, or if we will
657 be overriding an old definition. */
658 if (type_change_ok
659 || h->root.type == bfd_link_hash_undefined)
660 size_change_ok = true;
661
662 /* If we are looking at a dynamic object, and this is a
663 definition, we need to see if it has already been defined
664 by some other object. If it has, we want to use the
665 existing definition, and we do not want to report a
666 multiple symbol definition error; we do this by
667 clobbering sec to be bfd_und_section_ptr. */
668 if (dynamic && definition)
669 {
670 if (h->root.type == bfd_link_hash_defined
671 || h->root.type == bfd_link_hash_defweak
672 || (h->root.type == bfd_link_hash_common
673 && bind == STB_WEAK))
674 {
675 sec = bfd_und_section_ptr;
676 definition = false;
677 size_change_ok = true;
678 }
679 }
680
681 /* Similarly, if we are not looking at a dynamic object, and
682 we have a definition, we want to override any definition
683 we may have from a dynamic object. Symbols from regular
684 files always take precedence over symbols from dynamic
685 objects, even if they are defined after the dynamic
686 object in the link. */
687 if (! dynamic
688 && definition
689 && (h->root.type == bfd_link_hash_defined
690 || h->root.type == bfd_link_hash_defweak)
691 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0
692 && (bfd_get_flavour (h->root.u.def.section->owner)
693 == bfd_target_elf_flavour)
694 && (elf_elfheader (h->root.u.def.section->owner)->e_type
695 == ET_DYN))
696 {
697 /* Change the hash table entry to undefined, and let
698 _bfd_generic_link_add_one_symbol do the right thing
699 with the new definition. */
700 h->root.type = bfd_link_hash_undefined;
701 h->root.u.undef.abfd = h->root.u.def.section->owner;
702 size_change_ok = true;
703 }
704 }
705
706 if (! (_bfd_generic_link_add_one_symbol
707 (info, abfd, name, flags, sec, value, (const char *) NULL,
708 false, collect, (struct bfd_link_hash_entry **) sym_hash)))
709 goto error_return;
710
711 h = *sym_hash;
712 while (h->root.type == bfd_link_hash_indirect
713 || h->root.type == bfd_link_hash_warning)
714 h = (struct elf_link_hash_entry *) h->root.u.i.link;
715 *sym_hash = h;
716
717 new_weakdef = false;
718 if (dynamic
719 && definition
720 && (flags & BSF_WEAK) != 0
721 && ELF_ST_TYPE (sym.st_info) != STT_FUNC
722 && info->hash->creator->flavour == bfd_target_elf_flavour
723 && h->weakdef == NULL)
724 {
725 /* Keep a list of all weak defined non function symbols from
726 a dynamic object, using the weakdef field. Later in this
727 function we will set the weakdef field to the correct
728 value. We only put non-function symbols from dynamic
729 objects on this list, because that happens to be the only
730 time we need to know the normal symbol corresponding to a
731 weak symbol, and the information is time consuming to
732 figure out. If the weakdef field is not already NULL,
733 then this symbol was already defined by some previous
734 dynamic object, and we will be using that previous
735 definition anyhow. */
736
737 h->weakdef = weaks;
738 weaks = h;
739 new_weakdef = true;
740 }
741
742 /* Get the alignment of a common symbol. */
743 if (sym.st_shndx == SHN_COMMON
744 && h->root.type == bfd_link_hash_common)
745 h->root.u.c.p->alignment_power = bfd_log2 (sym.st_value);
746
747 if (info->hash->creator->flavour == bfd_target_elf_flavour)
748 {
749 int old_flags;
750 boolean dynsym;
751 int new_flag;
752
753 /* Remember the symbol size and type. */
754 if (sym.st_size != 0
755 && (definition || h->size == 0))
756 {
757 if (h->size != 0 && h->size != sym.st_size && ! size_change_ok)
758 (*_bfd_error_handler)
759 ("Warning: size of symbol `%s' changed from %lu to %lu in %s",
760 name, (unsigned long) h->size, (unsigned long) sym.st_size,
761 bfd_get_filename (abfd));
762
763 h->size = sym.st_size;
764 }
765 if (ELF_ST_TYPE (sym.st_info) != STT_NOTYPE
766 && (definition || h->type == STT_NOTYPE))
767 {
768 if (h->type != STT_NOTYPE
769 && h->type != ELF_ST_TYPE (sym.st_info)
770 && ! type_change_ok)
771 (*_bfd_error_handler)
772 ("Warning: type of symbol `%s' changed from %d to %d in %s",
773 name, h->type, ELF_ST_TYPE (sym.st_info),
774 bfd_get_filename (abfd));
775
776 h->type = ELF_ST_TYPE (sym.st_info);
777 }
778
779 /* Set a flag in the hash table entry indicating the type of
780 reference or definition we just found. Keep a count of
781 the number of dynamic symbols we find. A dynamic symbol
782 is one which is referenced or defined by both a regular
783 object and a shared object, or one which is referenced or
784 defined by more than one shared object. */
785 old_flags = h->elf_link_hash_flags;
786 dynsym = false;
787 if (! dynamic)
788 {
789 if (! definition)
790 new_flag = ELF_LINK_HASH_REF_REGULAR;
791 else
792 new_flag = ELF_LINK_HASH_DEF_REGULAR;
793 if (info->shared
794 || (old_flags & (ELF_LINK_HASH_DEF_DYNAMIC
795 | ELF_LINK_HASH_REF_DYNAMIC)) != 0)
796 dynsym = true;
797 }
798 else
799 {
800 if (! definition)
801 new_flag = ELF_LINK_HASH_REF_DYNAMIC;
802 else
803 new_flag = ELF_LINK_HASH_DEF_DYNAMIC;
804 if ((old_flags & new_flag) != 0
805 || (old_flags & (ELF_LINK_HASH_DEF_REGULAR
806 | ELF_LINK_HASH_REF_REGULAR)) != 0
807 || (h->weakdef != NULL
808 && (old_flags & (ELF_LINK_HASH_DEF_DYNAMIC
809 | ELF_LINK_HASH_REF_DYNAMIC)) != 0))
810 dynsym = true;
811 }
812
813 h->elf_link_hash_flags |= new_flag;
814 if (dynsym && h->dynindx == -1)
815 {
816 if (! _bfd_elf_link_record_dynamic_symbol (info, h))
817 goto error_return;
818 if (h->weakdef != NULL
819 && ! new_weakdef
820 && h->weakdef->dynindx == -1)
821 {
822 if (! _bfd_elf_link_record_dynamic_symbol (info,
823 h->weakdef))
824 goto error_return;
825 }
826 }
827 }
828 }
829
830 /* Now set the weakdefs field correctly for all the weak defined
831 symbols we found. The only way to do this is to search all the
832 symbols. Since we only need the information for non functions in
833 dynamic objects, that's the only time we actually put anything on
834 the list WEAKS. We need this information so that if a regular
835 object refers to a symbol defined weakly in a dynamic object, the
836 real symbol in the dynamic object is also put in the dynamic
837 symbols; we also must arrange for both symbols to point to the
838 same memory location. We could handle the general case of symbol
839 aliasing, but a general symbol alias can only be generated in
840 assembler code, handling it correctly would be very time
841 consuming, and other ELF linkers don't handle general aliasing
842 either. */
843 while (weaks != NULL)
844 {
845 struct elf_link_hash_entry *hlook;
846 asection *slook;
847 bfd_vma vlook;
848 struct elf_link_hash_entry **hpp;
849 struct elf_link_hash_entry **hppend;
850
851 hlook = weaks;
852 weaks = hlook->weakdef;
853 hlook->weakdef = NULL;
854
855 BFD_ASSERT (hlook->root.type == bfd_link_hash_defined
856 || hlook->root.type == bfd_link_hash_defweak
857 || hlook->root.type == bfd_link_hash_common
858 || hlook->root.type == bfd_link_hash_indirect);
859 slook = hlook->root.u.def.section;
860 vlook = hlook->root.u.def.value;
861
862 hpp = elf_sym_hashes (abfd);
863 hppend = hpp + extsymcount;
864 for (; hpp < hppend; hpp++)
865 {
866 struct elf_link_hash_entry *h;
867
868 h = *hpp;
869 if (h != NULL && h != hlook
870 && (h->root.type == bfd_link_hash_defined
871 || h->root.type == bfd_link_hash_defweak)
872 && h->root.u.def.section == slook
873 && h->root.u.def.value == vlook)
874 {
875 hlook->weakdef = h;
876
877 /* If the weak definition is in the list of dynamic
878 symbols, make sure the real definition is put there
879 as well. */
880 if (hlook->dynindx != -1
881 && h->dynindx == -1)
882 {
883 if (! _bfd_elf_link_record_dynamic_symbol (info, h))
884 goto error_return;
885 }
886
887 break;
888 }
889 }
890 }
891
892 if (buf != NULL)
893 {
894 free (buf);
895 buf = NULL;
896 }
897
898 /* If this object is the same format as the output object, and it is
899 not a shared library, then let the backend look through the
900 relocs.
901
902 This is required to build global offset table entries and to
903 arrange for dynamic relocs. It is not required for the
904 particular common case of linking non PIC code, even when linking
905 against shared libraries, but unfortunately there is no way of
906 knowing whether an object file has been compiled PIC or not.
907 Looking through the relocs is not particularly time consuming.
908 The problem is that we must either (1) keep the relocs in memory,
909 which causes the linker to require additional runtime memory or
910 (2) read the relocs twice from the input file, which wastes time.
911 This would be a good case for using mmap.
912
913 I have no idea how to handle linking PIC code into a file of a
914 different format. It probably can't be done. */
915 check_relocs = get_elf_backend_data (abfd)->check_relocs;
916 if (! dynamic
917 && abfd->xvec == info->hash->creator
918 && check_relocs != NULL)
919 {
920 asection *o;
921
922 for (o = abfd->sections; o != NULL; o = o->next)
923 {
924 Elf_Internal_Rela *internal_relocs;
925 boolean ok;
926
927 if ((o->flags & SEC_RELOC) == 0
928 || o->reloc_count == 0)
929 continue;
930
931 /* I believe we can ignore the relocs for any section which
932 does not form part of the final process image, such as a
933 debugging section. */
934 if ((o->flags & SEC_ALLOC) == 0)
935 continue;
936
937 internal_relocs = elf_link_read_relocs (abfd, o, (PTR) NULL,
938 (Elf_Internal_Rela *) NULL,
939 info->keep_memory);
940 if (internal_relocs == NULL)
941 goto error_return;
942
943 ok = (*check_relocs) (abfd, info, o, internal_relocs);
944
945 if (! info->keep_memory)
946 free (internal_relocs);
947
948 if (! ok)
949 goto error_return;
950 }
951 }
952
953 return true;
954
955 error_return:
956 if (buf != NULL)
957 free (buf);
958 if (dynbuf != NULL)
959 free (dynbuf);
960 return false;
961 }
962
963 /* Create some sections which will be filled in with dynamic linking
964 information. ABFD is an input file which requires dynamic sections
965 to be created. The dynamic sections take up virtual memory space
966 when the final executable is run, so we need to create them before
967 addresses are assigned to the output sections. We work out the
968 actual contents and size of these sections later. */
969
970 boolean
971 elf_link_create_dynamic_sections (abfd, info)
972 bfd *abfd;
973 struct bfd_link_info *info;
974 {
975 flagword flags;
976 register asection *s;
977 struct elf_link_hash_entry *h;
978 struct elf_backend_data *bed;
979
980 if (elf_hash_table (info)->dynamic_sections_created)
981 return true;
982
983 /* Make sure that all dynamic sections use the same input BFD. */
984 if (elf_hash_table (info)->dynobj == NULL)
985 elf_hash_table (info)->dynobj = abfd;
986 else
987 abfd = elf_hash_table (info)->dynobj;
988
989 /* Note that we set the SEC_IN_MEMORY flag for all of these
990 sections. */
991 flags = SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS | SEC_IN_MEMORY;
992
993 /* A dynamically linked executable has a .interp section, but a
994 shared library does not. */
995 if (! info->shared)
996 {
997 s = bfd_make_section (abfd, ".interp");
998 if (s == NULL
999 || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY))
1000 return false;
1001 }
1002
1003 s = bfd_make_section (abfd, ".dynsym");
1004 if (s == NULL
1005 || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
1006 || ! bfd_set_section_alignment (abfd, s, LOG_FILE_ALIGN))
1007 return false;
1008
1009 s = bfd_make_section (abfd, ".dynstr");
1010 if (s == NULL
1011 || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY))
1012 return false;
1013
1014 /* Create a strtab to hold the dynamic symbol names. */
1015 if (elf_hash_table (info)->dynstr == NULL)
1016 {
1017 elf_hash_table (info)->dynstr = elf_stringtab_init ();
1018 if (elf_hash_table (info)->dynstr == NULL)
1019 return false;
1020 }
1021
1022 s = bfd_make_section (abfd, ".dynamic");
1023 if (s == NULL
1024 || ! bfd_set_section_flags (abfd, s, flags)
1025 || ! bfd_set_section_alignment (abfd, s, LOG_FILE_ALIGN))
1026 return false;
1027
1028 /* The special symbol _DYNAMIC is always set to the start of the
1029 .dynamic section. This call occurs before we have processed the
1030 symbols for any dynamic object, so we don't have to worry about
1031 overriding a dynamic definition. We could set _DYNAMIC in a
1032 linker script, but we only want to define it if we are, in fact,
1033 creating a .dynamic section. We don't want to define it if there
1034 is no .dynamic section, since on some ELF platforms the start up
1035 code examines it to decide how to initialize the process. */
1036 h = NULL;
1037 if (! (_bfd_generic_link_add_one_symbol
1038 (info, abfd, "_DYNAMIC", BSF_GLOBAL, s, (bfd_vma) 0,
1039 (const char *) NULL, false, get_elf_backend_data (abfd)->collect,
1040 (struct bfd_link_hash_entry **) &h)))
1041 return false;
1042 h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
1043 h->type = STT_OBJECT;
1044
1045 if (info->shared
1046 && ! _bfd_elf_link_record_dynamic_symbol (info, h))
1047 return false;
1048
1049 s = bfd_make_section (abfd, ".hash");
1050 if (s == NULL
1051 || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
1052 || ! bfd_set_section_alignment (abfd, s, LOG_FILE_ALIGN))
1053 return false;
1054
1055 /* Let the backend create the rest of the sections. This lets the
1056 backend set the right flags. The backend will normally create
1057 the .got and .plt sections. */
1058 bed = get_elf_backend_data (abfd);
1059 if (! (*bed->elf_backend_create_dynamic_sections) (abfd, info))
1060 return false;
1061
1062 elf_hash_table (info)->dynamic_sections_created = true;
1063
1064 return true;
1065 }
1066
1067 /* Add an entry to the .dynamic table. */
1068
1069 boolean
1070 elf_add_dynamic_entry (info, tag, val)
1071 struct bfd_link_info *info;
1072 bfd_vma tag;
1073 bfd_vma val;
1074 {
1075 Elf_Internal_Dyn dyn;
1076 bfd *dynobj;
1077 asection *s;
1078 size_t newsize;
1079 bfd_byte *newcontents;
1080
1081 dynobj = elf_hash_table (info)->dynobj;
1082
1083 s = bfd_get_section_by_name (dynobj, ".dynamic");
1084 BFD_ASSERT (s != NULL);
1085
1086 newsize = s->_raw_size + sizeof (Elf_External_Dyn);
1087 newcontents = (bfd_byte *) bfd_realloc (s->contents, newsize);
1088 if (newcontents == NULL)
1089 return false;
1090
1091 dyn.d_tag = tag;
1092 dyn.d_un.d_val = val;
1093 elf_swap_dyn_out (dynobj, &dyn,
1094 (Elf_External_Dyn *) (newcontents + s->_raw_size));
1095
1096 s->_raw_size = newsize;
1097 s->contents = newcontents;
1098
1099 return true;
1100 }
1101
1102 /* Read and swap the relocs for a section. They may have been cached.
1103 If the EXTERNAL_RELOCS and INTERNAL_RELOCS arguments are not NULL,
1104 they are used as buffers to read into. They are known to be large
1105 enough. If the INTERNAL_RELOCS relocs argument is NULL, the return
1106 value is allocated using either malloc or bfd_alloc, according to
1107 the KEEP_MEMORY argument. */
1108
1109 static Elf_Internal_Rela *
1110 elf_link_read_relocs (abfd, o, external_relocs, internal_relocs, keep_memory)
1111 bfd *abfd;
1112 asection *o;
1113 PTR external_relocs;
1114 Elf_Internal_Rela *internal_relocs;
1115 boolean keep_memory;
1116 {
1117 Elf_Internal_Shdr *rel_hdr;
1118 PTR alloc1 = NULL;
1119 Elf_Internal_Rela *alloc2 = NULL;
1120
1121 if (elf_section_data (o)->relocs != NULL)
1122 return elf_section_data (o)->relocs;
1123
1124 if (o->reloc_count == 0)
1125 return NULL;
1126
1127 rel_hdr = &elf_section_data (o)->rel_hdr;
1128
1129 if (internal_relocs == NULL)
1130 {
1131 size_t size;
1132
1133 size = o->reloc_count * sizeof (Elf_Internal_Rela);
1134 if (keep_memory)
1135 internal_relocs = (Elf_Internal_Rela *) bfd_alloc (abfd, size);
1136 else
1137 internal_relocs = alloc2 = (Elf_Internal_Rela *) bfd_malloc (size);
1138 if (internal_relocs == NULL)
1139 goto error_return;
1140 }
1141
1142 if (external_relocs == NULL)
1143 {
1144 alloc1 = (PTR) bfd_malloc ((size_t) rel_hdr->sh_size);
1145 if (alloc1 == NULL)
1146 goto error_return;
1147 external_relocs = alloc1;
1148 }
1149
1150 if ((bfd_seek (abfd, rel_hdr->sh_offset, SEEK_SET) != 0)
1151 || (bfd_read (external_relocs, 1, rel_hdr->sh_size, abfd)
1152 != rel_hdr->sh_size))
1153 goto error_return;
1154
1155 /* Swap in the relocs. For convenience, we always produce an
1156 Elf_Internal_Rela array; if the relocs are Rel, we set the addend
1157 to 0. */
1158 if (rel_hdr->sh_entsize == sizeof (Elf_External_Rel))
1159 {
1160 Elf_External_Rel *erel;
1161 Elf_External_Rel *erelend;
1162 Elf_Internal_Rela *irela;
1163
1164 erel = (Elf_External_Rel *) external_relocs;
1165 erelend = erel + o->reloc_count;
1166 irela = internal_relocs;
1167 for (; erel < erelend; erel++, irela++)
1168 {
1169 Elf_Internal_Rel irel;
1170
1171 elf_swap_reloc_in (abfd, erel, &irel);
1172 irela->r_offset = irel.r_offset;
1173 irela->r_info = irel.r_info;
1174 irela->r_addend = 0;
1175 }
1176 }
1177 else
1178 {
1179 Elf_External_Rela *erela;
1180 Elf_External_Rela *erelaend;
1181 Elf_Internal_Rela *irela;
1182
1183 BFD_ASSERT (rel_hdr->sh_entsize == sizeof (Elf_External_Rela));
1184
1185 erela = (Elf_External_Rela *) external_relocs;
1186 erelaend = erela + o->reloc_count;
1187 irela = internal_relocs;
1188 for (; erela < erelaend; erela++, irela++)
1189 elf_swap_reloca_in (abfd, erela, irela);
1190 }
1191
1192 /* Cache the results for next time, if we can. */
1193 if (keep_memory)
1194 elf_section_data (o)->relocs = internal_relocs;
1195
1196 if (alloc1 != NULL)
1197 free (alloc1);
1198
1199 /* Don't free alloc2, since if it was allocated we are passing it
1200 back (under the name of internal_relocs). */
1201
1202 return internal_relocs;
1203
1204 error_return:
1205 if (alloc1 != NULL)
1206 free (alloc1);
1207 if (alloc2 != NULL)
1208 free (alloc2);
1209 return NULL;
1210 }
1211
1212 /* Record an assignment to a symbol made by a linker script. We need
1213 this in case some dynamic object refers to this symbol. */
1214
1215 /*ARGSUSED*/
1216 boolean
1217 NAME(bfd_elf,record_link_assignment) (output_bfd, info, name, provide)
1218 bfd *output_bfd;
1219 struct bfd_link_info *info;
1220 const char *name;
1221 boolean provide;
1222 {
1223 struct elf_link_hash_entry *h;
1224
1225 if (info->hash->creator->flavour != bfd_target_elf_flavour)
1226 return true;
1227
1228 h = elf_link_hash_lookup (elf_hash_table (info), name, true, true, false);
1229 if (h == NULL)
1230 return false;
1231
1232 /* If this symbol is being provided by the linker script, and it is
1233 currently defined by a dynamic object, but not by a regular
1234 object, then mark it as undefined so that the generic linker will
1235 force the correct value. */
1236 if (provide
1237 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0
1238 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
1239 h->root.type = bfd_link_hash_undefined;
1240
1241 h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
1242 h->type = STT_OBJECT;
1243
1244 if (((h->elf_link_hash_flags & (ELF_LINK_HASH_DEF_DYNAMIC
1245 | ELF_LINK_HASH_REF_DYNAMIC)) != 0
1246 || info->shared)
1247 && h->dynindx == -1)
1248 {
1249 if (! _bfd_elf_link_record_dynamic_symbol (info, h))
1250 return false;
1251
1252 /* If this is a weak defined symbol, and we know a corresponding
1253 real symbol from the same dynamic object, make sure the real
1254 symbol is also made into a dynamic symbol. */
1255 if (h->weakdef != NULL
1256 && h->weakdef->dynindx == -1)
1257 {
1258 if (! _bfd_elf_link_record_dynamic_symbol (info, h->weakdef))
1259 return false;
1260 }
1261 }
1262
1263 return true;
1264 }
1265
1266 /* Array used to determine the number of hash table buckets to use
1267 based on the number of symbols there are. If there are fewer than
1268 3 symbols we use 1 bucket, fewer than 17 symbols we use 3 buckets,
1269 fewer than 37 we use 17 buckets, and so forth. We never use more
1270 than 521 buckets. */
1271
1272 static const size_t elf_buckets[] =
1273 {
1274 1, 3, 17, 37, 67, 97, 131, 197, 263, 521, 0
1275 };
1276
1277 /* Set up the sizes and contents of the ELF dynamic sections. This is
1278 called by the ELF linker emulation before_allocation routine. We
1279 must set the sizes of the sections before the linker sets the
1280 addresses of the various sections. */
1281
1282 boolean
1283 NAME(bfd_elf,size_dynamic_sections) (output_bfd, soname, rpath,
1284 export_dynamic, info, sinterpptr)
1285 bfd *output_bfd;
1286 const char *soname;
1287 const char *rpath;
1288 boolean export_dynamic;
1289 struct bfd_link_info *info;
1290 asection **sinterpptr;
1291 {
1292 bfd *dynobj;
1293 struct elf_backend_data *bed;
1294
1295 *sinterpptr = NULL;
1296
1297 if (info->hash->creator->flavour != bfd_target_elf_flavour)
1298 return true;
1299
1300 dynobj = elf_hash_table (info)->dynobj;
1301
1302 /* If there were no dynamic objects in the link, there is nothing to
1303 do here. */
1304 if (dynobj == NULL)
1305 return true;
1306
1307 /* If we are supposed to export all symbols into the dynamic symbol
1308 table (this is not the normal case), then do so. */
1309 if (export_dynamic)
1310 {
1311 struct elf_info_failed eif;
1312
1313 eif.failed = false;
1314 eif.info = info;
1315 elf_link_hash_traverse (elf_hash_table (info), elf_export_symbol,
1316 (PTR) &eif);
1317 if (eif.failed)
1318 return false;
1319 }
1320
1321 if (elf_hash_table (info)->dynamic_sections_created)
1322 {
1323 struct elf_info_failed eif;
1324 struct elf_link_hash_entry *h;
1325 bfd_size_type strsize;
1326
1327 *sinterpptr = bfd_get_section_by_name (dynobj, ".interp");
1328 BFD_ASSERT (*sinterpptr != NULL || info->shared);
1329
1330 if (soname != NULL)
1331 {
1332 bfd_size_type indx;
1333
1334 indx = _bfd_stringtab_add (elf_hash_table (info)->dynstr, soname,
1335 true, true);
1336 if (indx == (bfd_size_type) -1
1337 || ! elf_add_dynamic_entry (info, DT_SONAME, indx))
1338 return false;
1339 }
1340
1341 if (info->symbolic)
1342 {
1343 if (! elf_add_dynamic_entry (info, DT_SYMBOLIC, 0))
1344 return false;
1345 }
1346
1347 if (rpath != NULL)
1348 {
1349 bfd_size_type indx;
1350
1351 indx = _bfd_stringtab_add (elf_hash_table (info)->dynstr, rpath,
1352 true, true);
1353 if (indx == (bfd_size_type) -1
1354 || ! elf_add_dynamic_entry (info, DT_RPATH, indx))
1355 return false;
1356 }
1357
1358 /* Find all symbols which were defined in a dynamic object and make
1359 the backend pick a reasonable value for them. */
1360 eif.failed = false;
1361 eif.info = info;
1362 elf_link_hash_traverse (elf_hash_table (info),
1363 elf_adjust_dynamic_symbol,
1364 (PTR) &eif);
1365 if (eif.failed)
1366 return false;
1367
1368 /* Add some entries to the .dynamic section. We fill in some of the
1369 values later, in elf_bfd_final_link, but we must add the entries
1370 now so that we know the final size of the .dynamic section. */
1371 h = elf_link_hash_lookup (elf_hash_table (info), "_init", false,
1372 false, false);
1373 if (h != NULL
1374 && (h->elf_link_hash_flags & (ELF_LINK_HASH_REF_REGULAR
1375 | ELF_LINK_HASH_DEF_REGULAR)) != 0)
1376 {
1377 if (! elf_add_dynamic_entry (info, DT_INIT, 0))
1378 return false;
1379 }
1380 h = elf_link_hash_lookup (elf_hash_table (info), "_fini", false,
1381 false, false);
1382 if (h != NULL
1383 && (h->elf_link_hash_flags & (ELF_LINK_HASH_REF_REGULAR
1384 | ELF_LINK_HASH_DEF_REGULAR)) != 0)
1385 {
1386 if (! elf_add_dynamic_entry (info, DT_FINI, 0))
1387 return false;
1388 }
1389 strsize = _bfd_stringtab_size (elf_hash_table (info)->dynstr);
1390 if (! elf_add_dynamic_entry (info, DT_HASH, 0)
1391 || ! elf_add_dynamic_entry (info, DT_STRTAB, 0)
1392 || ! elf_add_dynamic_entry (info, DT_SYMTAB, 0)
1393 || ! elf_add_dynamic_entry (info, DT_STRSZ, strsize)
1394 || ! elf_add_dynamic_entry (info, DT_SYMENT,
1395 sizeof (Elf_External_Sym)))
1396 return false;
1397 }
1398
1399 /* The backend must work out the sizes of all the other dynamic
1400 sections. */
1401 bed = get_elf_backend_data (output_bfd);
1402 if (! (*bed->elf_backend_size_dynamic_sections) (output_bfd, info))
1403 return false;
1404
1405 if (elf_hash_table (info)->dynamic_sections_created)
1406 {
1407 size_t dynsymcount;
1408 asection *s;
1409 size_t i;
1410 size_t bucketcount = 0;
1411 Elf_Internal_Sym isym;
1412
1413 /* Set the size of the .dynsym and .hash sections. We counted
1414 the number of dynamic symbols in elf_link_add_object_symbols.
1415 We will build the contents of .dynsym and .hash when we build
1416 the final symbol table, because until then we do not know the
1417 correct value to give the symbols. We built the .dynstr
1418 section as we went along in elf_link_add_object_symbols. */
1419 dynsymcount = elf_hash_table (info)->dynsymcount;
1420 s = bfd_get_section_by_name (dynobj, ".dynsym");
1421 BFD_ASSERT (s != NULL);
1422 s->_raw_size = dynsymcount * sizeof (Elf_External_Sym);
1423 s->contents = (bfd_byte *) bfd_alloc (output_bfd, s->_raw_size);
1424 if (s->contents == NULL && s->_raw_size != 0)
1425 return false;
1426
1427 /* The first entry in .dynsym is a dummy symbol. */
1428 isym.st_value = 0;
1429 isym.st_size = 0;
1430 isym.st_name = 0;
1431 isym.st_info = 0;
1432 isym.st_other = 0;
1433 isym.st_shndx = 0;
1434 elf_swap_symbol_out (output_bfd, &isym,
1435 (PTR) (Elf_External_Sym *) s->contents);
1436
1437 for (i = 0; elf_buckets[i] != 0; i++)
1438 {
1439 bucketcount = elf_buckets[i];
1440 if (dynsymcount < elf_buckets[i + 1])
1441 break;
1442 }
1443
1444 s = bfd_get_section_by_name (dynobj, ".hash");
1445 BFD_ASSERT (s != NULL);
1446 s->_raw_size = (2 + bucketcount + dynsymcount) * (ARCH_SIZE / 8);
1447 s->contents = (bfd_byte *) bfd_alloc (output_bfd, s->_raw_size);
1448 if (s->contents == NULL)
1449 return false;
1450 memset (s->contents, 0, (size_t) s->_raw_size);
1451
1452 put_word (output_bfd, bucketcount, s->contents);
1453 put_word (output_bfd, dynsymcount, s->contents + (ARCH_SIZE / 8));
1454
1455 elf_hash_table (info)->bucketcount = bucketcount;
1456
1457 s = bfd_get_section_by_name (dynobj, ".dynstr");
1458 BFD_ASSERT (s != NULL);
1459 s->_raw_size = _bfd_stringtab_size (elf_hash_table (info)->dynstr);
1460
1461 if (! elf_add_dynamic_entry (info, DT_NULL, 0))
1462 return false;
1463 }
1464
1465 return true;
1466 }
1467
1468 /* This routine is used to export all defined symbols into the dynamic
1469 symbol table. It is called via elf_link_hash_traverse. */
1470
1471 static boolean
1472 elf_export_symbol (h, data)
1473 struct elf_link_hash_entry *h;
1474 PTR data;
1475 {
1476 struct elf_info_failed *eif = (struct elf_info_failed *) data;
1477
1478 if (h->dynindx == -1
1479 && (h->elf_link_hash_flags
1480 & (ELF_LINK_HASH_DEF_REGULAR | ELF_LINK_HASH_REF_REGULAR)) != 0)
1481 {
1482 if (! _bfd_elf_link_record_dynamic_symbol (eif->info, h))
1483 {
1484 eif->failed = true;
1485 return false;
1486 }
1487 }
1488
1489 return true;
1490 }
1491
1492 /* Make the backend pick a good value for a dynamic symbol. This is
1493 called via elf_link_hash_traverse, and also calls itself
1494 recursively. */
1495
1496 static boolean
1497 elf_adjust_dynamic_symbol (h, data)
1498 struct elf_link_hash_entry *h;
1499 PTR data;
1500 {
1501 struct elf_info_failed *eif = (struct elf_info_failed *) data;
1502 bfd *dynobj;
1503 struct elf_backend_data *bed;
1504
1505 /* If -Bsymbolic was used (which means to bind references to global
1506 symbols to the definition within the shared object), and this
1507 symbol was defined in a regular object, then it actually doesn't
1508 need a PLT entry. */
1509 if ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) != 0
1510 && eif->info->shared
1511 && eif->info->symbolic
1512 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0)
1513 h->elf_link_hash_flags &=~ ELF_LINK_HASH_NEEDS_PLT;
1514
1515 /* If this symbol does not require a PLT entry, and it is not
1516 defined by a dynamic object, or is not referenced by a regular
1517 object, ignore it. We do have to handle a weak defined symbol,
1518 even if no regular object refers to it, if we decided to add it
1519 to the dynamic symbol table. FIXME: Do we normally need to worry
1520 about symbols which are defined by one dynamic object and
1521 referenced by another one? */
1522 if ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) == 0
1523 && ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0
1524 || (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) == 0
1525 || ((h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) == 0
1526 && (h->weakdef == NULL || h->weakdef->dynindx == -1))))
1527 return true;
1528
1529 /* If we've already adjusted this symbol, don't do it again. This
1530 can happen via a recursive call. */
1531 if ((h->elf_link_hash_flags & ELF_LINK_HASH_DYNAMIC_ADJUSTED) != 0)
1532 return true;
1533
1534 /* Don't look at this symbol again. Note that we must set this
1535 after checking the above conditions, because we may look at a
1536 symbol once, decide not to do anything, and then get called
1537 recursively later after REF_REGULAR is set below. */
1538 h->elf_link_hash_flags |= ELF_LINK_HASH_DYNAMIC_ADJUSTED;
1539
1540 /* If this is a weak definition, and we know a real definition, and
1541 the real symbol is not itself defined by a regular object file,
1542 then get a good value for the real definition. We handle the
1543 real symbol first, for the convenience of the backend routine.
1544
1545 Note that there is a confusing case here. If the real definition
1546 is defined by a regular object file, we don't get the real symbol
1547 from the dynamic object, but we do get the weak symbol. If the
1548 processor backend uses a COPY reloc, then if some routine in the
1549 dynamic object changes the real symbol, we will not see that
1550 change in the corresponding weak symbol. This is the way other
1551 ELF linkers work as well, and seems to be a result of the shared
1552 library model.
1553
1554 I will clarify this issue. Most SVR4 shared libraries define the
1555 variable _timezone and define timezone as a weak synonym. The
1556 tzset call changes _timezone. If you write
1557 extern int timezone;
1558 int _timezone = 5;
1559 int main () { tzset (); printf ("%d %d\n", timezone, _timezone); }
1560 you might expect that, since timezone is a synonym for _timezone,
1561 the same number will print both times. However, if the processor
1562 backend uses a COPY reloc, then actually timezone will be copied
1563 into your process image, and, since you define _timezone
1564 yourself, _timezone will not. Thus timezone and _timezone will
1565 wind up at different memory locations. The tzset call will set
1566 _timezone, leaving timezone unchanged. */
1567
1568 if (h->weakdef != NULL)
1569 {
1570 struct elf_link_hash_entry *weakdef;
1571
1572 BFD_ASSERT (h->root.type == bfd_link_hash_defined
1573 || h->root.type == bfd_link_hash_defweak);
1574 weakdef = h->weakdef;
1575 BFD_ASSERT (weakdef->root.type == bfd_link_hash_defined
1576 || weakdef->root.type == bfd_link_hash_defweak);
1577 BFD_ASSERT (weakdef->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC);
1578 if ((weakdef->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0)
1579 {
1580 /* This symbol is defined by a regular object file, so we
1581 will not do anything special. Clear weakdef for the
1582 convenience of the processor backend. */
1583 h->weakdef = NULL;
1584 }
1585 else
1586 {
1587 /* There is an implicit reference by a regular object file
1588 via the weak symbol. */
1589 weakdef->elf_link_hash_flags |= ELF_LINK_HASH_REF_REGULAR;
1590 if (! elf_adjust_dynamic_symbol (weakdef, (PTR) eif))
1591 return false;
1592 }
1593 }
1594
1595 dynobj = elf_hash_table (eif->info)->dynobj;
1596 bed = get_elf_backend_data (dynobj);
1597 if (! (*bed->elf_backend_adjust_dynamic_symbol) (eif->info, h))
1598 {
1599 eif->failed = true;
1600 return false;
1601 }
1602
1603 return true;
1604 }
1605 \f
1606 /* Final phase of ELF linker. */
1607
1608 /* A structure we use to avoid passing large numbers of arguments. */
1609
1610 struct elf_final_link_info
1611 {
1612 /* General link information. */
1613 struct bfd_link_info *info;
1614 /* Output BFD. */
1615 bfd *output_bfd;
1616 /* Symbol string table. */
1617 struct bfd_strtab_hash *symstrtab;
1618 /* .dynsym section. */
1619 asection *dynsym_sec;
1620 /* .hash section. */
1621 asection *hash_sec;
1622 /* Buffer large enough to hold contents of any section. */
1623 bfd_byte *contents;
1624 /* Buffer large enough to hold external relocs of any section. */
1625 PTR external_relocs;
1626 /* Buffer large enough to hold internal relocs of any section. */
1627 Elf_Internal_Rela *internal_relocs;
1628 /* Buffer large enough to hold external local symbols of any input
1629 BFD. */
1630 Elf_External_Sym *external_syms;
1631 /* Buffer large enough to hold internal local symbols of any input
1632 BFD. */
1633 Elf_Internal_Sym *internal_syms;
1634 /* Array large enough to hold a symbol index for each local symbol
1635 of any input BFD. */
1636 long *indices;
1637 /* Array large enough to hold a section pointer for each local
1638 symbol of any input BFD. */
1639 asection **sections;
1640 /* Buffer to hold swapped out symbols. */
1641 Elf_External_Sym *symbuf;
1642 /* Number of swapped out symbols in buffer. */
1643 size_t symbuf_count;
1644 /* Number of symbols which fit in symbuf. */
1645 size_t symbuf_size;
1646 };
1647
1648 static boolean elf_link_output_sym
1649 PARAMS ((struct elf_final_link_info *, const char *,
1650 Elf_Internal_Sym *, asection *));
1651 static boolean elf_link_flush_output_syms
1652 PARAMS ((struct elf_final_link_info *));
1653 static boolean elf_link_output_extsym
1654 PARAMS ((struct elf_link_hash_entry *, PTR));
1655 static boolean elf_link_input_bfd
1656 PARAMS ((struct elf_final_link_info *, bfd *));
1657 static boolean elf_reloc_link_order
1658 PARAMS ((bfd *, struct bfd_link_info *, asection *,
1659 struct bfd_link_order *));
1660
1661 /* This struct is used to pass information to routines called via
1662 elf_link_hash_traverse which must return failure. */
1663
1664 struct elf_finfo_failed
1665 {
1666 boolean failed;
1667 struct elf_final_link_info *finfo;
1668 };
1669
1670 /* Do the final step of an ELF link. */
1671
1672 boolean
1673 elf_bfd_final_link (abfd, info)
1674 bfd *abfd;
1675 struct bfd_link_info *info;
1676 {
1677 boolean dynamic;
1678 bfd *dynobj;
1679 struct elf_final_link_info finfo;
1680 register asection *o;
1681 register struct bfd_link_order *p;
1682 register bfd *sub;
1683 size_t max_contents_size;
1684 size_t max_external_reloc_size;
1685 size_t max_internal_reloc_count;
1686 size_t max_sym_count;
1687 file_ptr off;
1688 Elf_Internal_Sym elfsym;
1689 unsigned int i;
1690 Elf_Internal_Shdr *symtab_hdr;
1691 Elf_Internal_Shdr *symstrtab_hdr;
1692 struct elf_backend_data *bed = get_elf_backend_data (abfd);
1693 struct elf_finfo_failed eif;
1694
1695 if (info->shared)
1696 abfd->flags |= DYNAMIC;
1697
1698 dynamic = elf_hash_table (info)->dynamic_sections_created;
1699 dynobj = elf_hash_table (info)->dynobj;
1700
1701 finfo.info = info;
1702 finfo.output_bfd = abfd;
1703 finfo.symstrtab = elf_stringtab_init ();
1704 if (finfo.symstrtab == NULL)
1705 return false;
1706 if (! dynamic)
1707 {
1708 finfo.dynsym_sec = NULL;
1709 finfo.hash_sec = NULL;
1710 }
1711 else
1712 {
1713 finfo.dynsym_sec = bfd_get_section_by_name (dynobj, ".dynsym");
1714 finfo.hash_sec = bfd_get_section_by_name (dynobj, ".hash");
1715 BFD_ASSERT (finfo.dynsym_sec != NULL && finfo.hash_sec != NULL);
1716 }
1717 finfo.contents = NULL;
1718 finfo.external_relocs = NULL;
1719 finfo.internal_relocs = NULL;
1720 finfo.external_syms = NULL;
1721 finfo.internal_syms = NULL;
1722 finfo.indices = NULL;
1723 finfo.sections = NULL;
1724 finfo.symbuf = NULL;
1725 finfo.symbuf_count = 0;
1726
1727 /* Count up the number of relocations we will output for each output
1728 section, so that we know the sizes of the reloc sections. We
1729 also figure out some maximum sizes. */
1730 max_contents_size = 0;
1731 max_external_reloc_size = 0;
1732 max_internal_reloc_count = 0;
1733 max_sym_count = 0;
1734 for (o = abfd->sections; o != (asection *) NULL; o = o->next)
1735 {
1736 o->reloc_count = 0;
1737
1738 for (p = o->link_order_head; p != NULL; p = p->next)
1739 {
1740 if (p->type == bfd_section_reloc_link_order
1741 || p->type == bfd_symbol_reloc_link_order)
1742 ++o->reloc_count;
1743 else if (p->type == bfd_indirect_link_order)
1744 {
1745 asection *sec;
1746
1747 sec = p->u.indirect.section;
1748
1749 if (info->relocateable)
1750 o->reloc_count += sec->reloc_count;
1751
1752 if (sec->_raw_size > max_contents_size)
1753 max_contents_size = sec->_raw_size;
1754 if (sec->_cooked_size > max_contents_size)
1755 max_contents_size = sec->_cooked_size;
1756
1757 /* We are interested in just local symbols, not all
1758 symbols. */
1759 if (bfd_get_flavour (sec->owner) == bfd_target_elf_flavour)
1760 {
1761 size_t sym_count;
1762
1763 if (elf_bad_symtab (sec->owner))
1764 sym_count = (elf_tdata (sec->owner)->symtab_hdr.sh_size
1765 / sizeof (Elf_External_Sym));
1766 else
1767 sym_count = elf_tdata (sec->owner)->symtab_hdr.sh_info;
1768
1769 if (sym_count > max_sym_count)
1770 max_sym_count = sym_count;
1771
1772 if ((sec->flags & SEC_RELOC) != 0)
1773 {
1774 size_t ext_size;
1775
1776 ext_size = elf_section_data (sec)->rel_hdr.sh_size;
1777 if (ext_size > max_external_reloc_size)
1778 max_external_reloc_size = ext_size;
1779 if (sec->reloc_count > max_internal_reloc_count)
1780 max_internal_reloc_count = sec->reloc_count;
1781 }
1782 }
1783 }
1784 }
1785
1786 if (o->reloc_count > 0)
1787 o->flags |= SEC_RELOC;
1788 else
1789 {
1790 /* Explicitly clear the SEC_RELOC flag. The linker tends to
1791 set it (this is probably a bug) and if it is set
1792 assign_section_numbers will create a reloc section. */
1793 o->flags &=~ SEC_RELOC;
1794 }
1795
1796 /* If the SEC_ALLOC flag is not set, force the section VMA to
1797 zero. This is done in elf_fake_sections as well, but forcing
1798 the VMA to 0 here will ensure that relocs against these
1799 sections are handled correctly. */
1800 if ((o->flags & SEC_ALLOC) == 0)
1801 o->vma = 0;
1802 }
1803
1804 /* Figure out the file positions for everything but the symbol table
1805 and the relocs. We set symcount to force assign_section_numbers
1806 to create a symbol table. */
1807 abfd->symcount = info->strip == strip_all ? 0 : 1;
1808 BFD_ASSERT (! abfd->output_has_begun);
1809 if (! _bfd_elf_compute_section_file_positions (abfd, info))
1810 goto error_return;
1811
1812 /* That created the reloc sections. Set their sizes, and assign
1813 them file positions, and allocate some buffers. */
1814 for (o = abfd->sections; o != NULL; o = o->next)
1815 {
1816 if ((o->flags & SEC_RELOC) != 0)
1817 {
1818 Elf_Internal_Shdr *rel_hdr;
1819 register struct elf_link_hash_entry **p, **pend;
1820
1821 rel_hdr = &elf_section_data (o)->rel_hdr;
1822
1823 rel_hdr->sh_size = rel_hdr->sh_entsize * o->reloc_count;
1824
1825 /* The contents field must last into write_object_contents,
1826 so we allocate it with bfd_alloc rather than malloc. */
1827 rel_hdr->contents = (PTR) bfd_alloc (abfd, rel_hdr->sh_size);
1828 if (rel_hdr->contents == NULL && rel_hdr->sh_size != 0)
1829 goto error_return;
1830
1831 p = ((struct elf_link_hash_entry **)
1832 bfd_malloc (o->reloc_count
1833 * sizeof (struct elf_link_hash_entry *)));
1834 if (p == NULL && o->reloc_count != 0)
1835 goto error_return;
1836 elf_section_data (o)->rel_hashes = p;
1837 pend = p + o->reloc_count;
1838 for (; p < pend; p++)
1839 *p = NULL;
1840
1841 /* Use the reloc_count field as an index when outputting the
1842 relocs. */
1843 o->reloc_count = 0;
1844 }
1845 }
1846
1847 _bfd_elf_assign_file_positions_for_relocs (abfd);
1848
1849 /* We have now assigned file positions for all the sections except
1850 .symtab and .strtab. We start the .symtab section at the current
1851 file position, and write directly to it. We build the .strtab
1852 section in memory. */
1853 abfd->symcount = 0;
1854 symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
1855 /* sh_name is set in prep_headers. */
1856 symtab_hdr->sh_type = SHT_SYMTAB;
1857 symtab_hdr->sh_flags = 0;
1858 symtab_hdr->sh_addr = 0;
1859 symtab_hdr->sh_size = 0;
1860 symtab_hdr->sh_entsize = sizeof (Elf_External_Sym);
1861 /* sh_link is set in assign_section_numbers. */
1862 /* sh_info is set below. */
1863 /* sh_offset is set just below. */
1864 symtab_hdr->sh_addralign = 4; /* FIXME: system dependent? */
1865
1866 off = elf_tdata (abfd)->next_file_pos;
1867 off = _bfd_elf_assign_file_position_for_section (symtab_hdr, off, true);
1868
1869 /* Note that at this point elf_tdata (abfd)->next_file_pos is
1870 incorrect. We do not yet know the size of the .symtab section.
1871 We correct next_file_pos below, after we do know the size. */
1872
1873 /* Allocate a buffer to hold swapped out symbols. This is to avoid
1874 continuously seeking to the right position in the file. */
1875 if (! info->keep_memory || max_sym_count < 20)
1876 finfo.symbuf_size = 20;
1877 else
1878 finfo.symbuf_size = max_sym_count;
1879 finfo.symbuf = ((Elf_External_Sym *)
1880 bfd_malloc (finfo.symbuf_size * sizeof (Elf_External_Sym)));
1881 if (finfo.symbuf == NULL)
1882 goto error_return;
1883
1884 /* Start writing out the symbol table. The first symbol is always a
1885 dummy symbol. */
1886 elfsym.st_value = 0;
1887 elfsym.st_size = 0;
1888 elfsym.st_info = 0;
1889 elfsym.st_other = 0;
1890 elfsym.st_shndx = SHN_UNDEF;
1891 if (! elf_link_output_sym (&finfo, (const char *) NULL,
1892 &elfsym, bfd_und_section_ptr))
1893 goto error_return;
1894
1895 #if 0
1896 /* Some standard ELF linkers do this, but we don't because it causes
1897 bootstrap comparison failures. */
1898 /* Output a file symbol for the output file as the second symbol.
1899 We output this even if we are discarding local symbols, although
1900 I'm not sure if this is correct. */
1901 elfsym.st_value = 0;
1902 elfsym.st_size = 0;
1903 elfsym.st_info = ELF_ST_INFO (STB_LOCAL, STT_FILE);
1904 elfsym.st_other = 0;
1905 elfsym.st_shndx = SHN_ABS;
1906 if (! elf_link_output_sym (&finfo, bfd_get_filename (abfd),
1907 &elfsym, bfd_abs_section_ptr))
1908 goto error_return;
1909 #endif
1910
1911 /* Output a symbol for each section. We output these even if we are
1912 discarding local symbols, since they are used for relocs. These
1913 symbols have no names. We store the index of each one in the
1914 index field of the section, so that we can find it again when
1915 outputting relocs. */
1916 elfsym.st_value = 0;
1917 elfsym.st_size = 0;
1918 elfsym.st_info = ELF_ST_INFO (STB_LOCAL, STT_SECTION);
1919 elfsym.st_other = 0;
1920 for (i = 1; i < elf_elfheader (abfd)->e_shnum; i++)
1921 {
1922 o = section_from_elf_index (abfd, i);
1923 if (o != NULL)
1924 o->target_index = abfd->symcount;
1925 elfsym.st_shndx = i;
1926 if (! elf_link_output_sym (&finfo, (const char *) NULL,
1927 &elfsym, o))
1928 goto error_return;
1929 }
1930
1931 /* Allocate some memory to hold information read in from the input
1932 files. */
1933 finfo.contents = (bfd_byte *) bfd_malloc (max_contents_size);
1934 finfo.external_relocs = (PTR) bfd_malloc (max_external_reloc_size);
1935 finfo.internal_relocs = ((Elf_Internal_Rela *)
1936 bfd_malloc (max_internal_reloc_count
1937 * sizeof (Elf_Internal_Rela)));
1938 finfo.external_syms = ((Elf_External_Sym *)
1939 bfd_malloc (max_sym_count
1940 * sizeof (Elf_External_Sym)));
1941 finfo.internal_syms = ((Elf_Internal_Sym *)
1942 bfd_malloc (max_sym_count
1943 * sizeof (Elf_Internal_Sym)));
1944 finfo.indices = (long *) bfd_malloc (max_sym_count * sizeof (long));
1945 finfo.sections = ((asection **)
1946 bfd_malloc (max_sym_count * sizeof (asection *)));
1947 if ((finfo.contents == NULL && max_contents_size != 0)
1948 || (finfo.external_relocs == NULL && max_external_reloc_size != 0)
1949 || (finfo.internal_relocs == NULL && max_internal_reloc_count != 0)
1950 || (finfo.external_syms == NULL && max_sym_count != 0)
1951 || (finfo.internal_syms == NULL && max_sym_count != 0)
1952 || (finfo.indices == NULL && max_sym_count != 0)
1953 || (finfo.sections == NULL && max_sym_count != 0))
1954 goto error_return;
1955
1956 /* Since ELF permits relocations to be against local symbols, we
1957 must have the local symbols available when we do the relocations.
1958 Since we would rather only read the local symbols once, and we
1959 would rather not keep them in memory, we handle all the
1960 relocations for a single input file at the same time.
1961
1962 Unfortunately, there is no way to know the total number of local
1963 symbols until we have seen all of them, and the local symbol
1964 indices precede the global symbol indices. This means that when
1965 we are generating relocateable output, and we see a reloc against
1966 a global symbol, we can not know the symbol index until we have
1967 finished examining all the local symbols to see which ones we are
1968 going to output. To deal with this, we keep the relocations in
1969 memory, and don't output them until the end of the link. This is
1970 an unfortunate waste of memory, but I don't see a good way around
1971 it. Fortunately, it only happens when performing a relocateable
1972 link, which is not the common case. FIXME: If keep_memory is set
1973 we could write the relocs out and then read them again; I don't
1974 know how bad the memory loss will be. */
1975
1976 for (sub = info->input_bfds; sub != NULL; sub = sub->next)
1977 sub->output_has_begun = false;
1978 for (o = abfd->sections; o != NULL; o = o->next)
1979 {
1980 for (p = o->link_order_head; p != NULL; p = p->next)
1981 {
1982 if (p->type == bfd_indirect_link_order
1983 && (bfd_get_flavour (p->u.indirect.section->owner)
1984 == bfd_target_elf_flavour))
1985 {
1986 sub = p->u.indirect.section->owner;
1987 if (! sub->output_has_begun)
1988 {
1989 if (! elf_link_input_bfd (&finfo, sub))
1990 goto error_return;
1991 sub->output_has_begun = true;
1992 }
1993 }
1994 else if (p->type == bfd_section_reloc_link_order
1995 || p->type == bfd_symbol_reloc_link_order)
1996 {
1997 if (! elf_reloc_link_order (abfd, info, o, p))
1998 goto error_return;
1999 }
2000 else
2001 {
2002 if (! _bfd_default_link_order (abfd, info, o, p))
2003 goto error_return;
2004 }
2005 }
2006 }
2007
2008 /* That wrote out all the local symbols. Finish up the symbol table
2009 with the global symbols. */
2010
2011 /* The sh_info field records the index of the first non local
2012 symbol. */
2013 symtab_hdr->sh_info = abfd->symcount;
2014 if (dynamic)
2015 elf_section_data (finfo.dynsym_sec->output_section)->this_hdr.sh_info = 1;
2016
2017 /* We get the global symbols from the hash table. */
2018 eif.failed = false;
2019 eif.finfo = &finfo;
2020 elf_link_hash_traverse (elf_hash_table (info), elf_link_output_extsym,
2021 (PTR) &eif);
2022 if (eif.failed)
2023 return false;
2024
2025 /* Flush all symbols to the file. */
2026 if (! elf_link_flush_output_syms (&finfo))
2027 return false;
2028
2029 /* Now we know the size of the symtab section. */
2030 off += symtab_hdr->sh_size;
2031
2032 /* Finish up and write out the symbol string table (.strtab)
2033 section. */
2034 symstrtab_hdr = &elf_tdata (abfd)->strtab_hdr;
2035 /* sh_name was set in prep_headers. */
2036 symstrtab_hdr->sh_type = SHT_STRTAB;
2037 symstrtab_hdr->sh_flags = 0;
2038 symstrtab_hdr->sh_addr = 0;
2039 symstrtab_hdr->sh_size = _bfd_stringtab_size (finfo.symstrtab);
2040 symstrtab_hdr->sh_entsize = 0;
2041 symstrtab_hdr->sh_link = 0;
2042 symstrtab_hdr->sh_info = 0;
2043 /* sh_offset is set just below. */
2044 symstrtab_hdr->sh_addralign = 1;
2045
2046 off = _bfd_elf_assign_file_position_for_section (symstrtab_hdr, off, true);
2047 elf_tdata (abfd)->next_file_pos = off;
2048
2049 if (bfd_seek (abfd, symstrtab_hdr->sh_offset, SEEK_SET) != 0
2050 || ! _bfd_stringtab_emit (abfd, finfo.symstrtab))
2051 return false;
2052
2053 /* Adjust the relocs to have the correct symbol indices. */
2054 for (o = abfd->sections; o != NULL; o = o->next)
2055 {
2056 struct elf_link_hash_entry **rel_hash;
2057 Elf_Internal_Shdr *rel_hdr;
2058
2059 if ((o->flags & SEC_RELOC) == 0)
2060 continue;
2061
2062 rel_hash = elf_section_data (o)->rel_hashes;
2063 rel_hdr = &elf_section_data (o)->rel_hdr;
2064 for (i = 0; i < o->reloc_count; i++, rel_hash++)
2065 {
2066 if (*rel_hash == NULL)
2067 continue;
2068
2069 BFD_ASSERT ((*rel_hash)->indx >= 0);
2070
2071 if (rel_hdr->sh_entsize == sizeof (Elf_External_Rel))
2072 {
2073 Elf_External_Rel *erel;
2074 Elf_Internal_Rel irel;
2075
2076 erel = (Elf_External_Rel *) rel_hdr->contents + i;
2077 elf_swap_reloc_in (abfd, erel, &irel);
2078 irel.r_info = ELF_R_INFO ((*rel_hash)->indx,
2079 ELF_R_TYPE (irel.r_info));
2080 elf_swap_reloc_out (abfd, &irel, erel);
2081 }
2082 else
2083 {
2084 Elf_External_Rela *erela;
2085 Elf_Internal_Rela irela;
2086
2087 BFD_ASSERT (rel_hdr->sh_entsize
2088 == sizeof (Elf_External_Rela));
2089
2090 erela = (Elf_External_Rela *) rel_hdr->contents + i;
2091 elf_swap_reloca_in (abfd, erela, &irela);
2092 irela.r_info = ELF_R_INFO ((*rel_hash)->indx,
2093 ELF_R_TYPE (irela.r_info));
2094 elf_swap_reloca_out (abfd, &irela, erela);
2095 }
2096 }
2097
2098 /* Set the reloc_count field to 0 to prevent write_relocs from
2099 trying to swap the relocs out itself. */
2100 o->reloc_count = 0;
2101 }
2102
2103 /* If we are linking against a dynamic object, or generating a
2104 shared library, finish up the dynamic linking information. */
2105 if (dynamic)
2106 {
2107 Elf_External_Dyn *dyncon, *dynconend;
2108
2109 /* Fix up .dynamic entries. */
2110 o = bfd_get_section_by_name (dynobj, ".dynamic");
2111 BFD_ASSERT (o != NULL);
2112
2113 dyncon = (Elf_External_Dyn *) o->contents;
2114 dynconend = (Elf_External_Dyn *) (o->contents + o->_raw_size);
2115 for (; dyncon < dynconend; dyncon++)
2116 {
2117 Elf_Internal_Dyn dyn;
2118 const char *name;
2119 unsigned int type;
2120
2121 elf_swap_dyn_in (dynobj, dyncon, &dyn);
2122
2123 switch (dyn.d_tag)
2124 {
2125 default:
2126 break;
2127
2128 /* SVR4 linkers seem to set DT_INIT and DT_FINI based on
2129 magic _init and _fini symbols. This is pretty ugly,
2130 but we are compatible. */
2131 case DT_INIT:
2132 name = "_init";
2133 goto get_sym;
2134 case DT_FINI:
2135 name = "_fini";
2136 get_sym:
2137 {
2138 struct elf_link_hash_entry *h;
2139
2140 h = elf_link_hash_lookup (elf_hash_table (info), name,
2141 false, false, true);
2142 if (h != NULL
2143 && (h->root.type == bfd_link_hash_defined
2144 || h->root.type == bfd_link_hash_defweak))
2145 {
2146 dyn.d_un.d_val = h->root.u.def.value;
2147 o = h->root.u.def.section;
2148 if (o->output_section != NULL)
2149 dyn.d_un.d_val += (o->output_section->vma
2150 + o->output_offset);
2151 else
2152 {
2153 /* The symbol is imported from another shared
2154 library and does not apply to this one. */
2155 dyn.d_un.d_val = 0;
2156 }
2157
2158 elf_swap_dyn_out (dynobj, &dyn, dyncon);
2159 }
2160 }
2161 break;
2162
2163 case DT_HASH:
2164 name = ".hash";
2165 goto get_vma;
2166 case DT_STRTAB:
2167 name = ".dynstr";
2168 goto get_vma;
2169 case DT_SYMTAB:
2170 name = ".dynsym";
2171 get_vma:
2172 o = bfd_get_section_by_name (abfd, name);
2173 BFD_ASSERT (o != NULL);
2174 dyn.d_un.d_ptr = o->vma;
2175 elf_swap_dyn_out (dynobj, &dyn, dyncon);
2176 break;
2177
2178 case DT_REL:
2179 case DT_RELA:
2180 case DT_RELSZ:
2181 case DT_RELASZ:
2182 if (dyn.d_tag == DT_REL || dyn.d_tag == DT_RELSZ)
2183 type = SHT_REL;
2184 else
2185 type = SHT_RELA;
2186 dyn.d_un.d_val = 0;
2187 for (i = 1; i < elf_elfheader (abfd)->e_shnum; i++)
2188 {
2189 Elf_Internal_Shdr *hdr;
2190
2191 hdr = elf_elfsections (abfd)[i];
2192 if (hdr->sh_type == type
2193 && (hdr->sh_flags & SHF_ALLOC) != 0)
2194 {
2195 if (dyn.d_tag == DT_RELSZ || dyn.d_tag == DT_RELASZ)
2196 dyn.d_un.d_val += hdr->sh_size;
2197 else
2198 {
2199 if (dyn.d_un.d_val == 0
2200 || hdr->sh_addr < dyn.d_un.d_val)
2201 dyn.d_un.d_val = hdr->sh_addr;
2202 }
2203 }
2204 }
2205 elf_swap_dyn_out (dynobj, &dyn, dyncon);
2206 break;
2207 }
2208 }
2209 }
2210
2211 /* If we have created any dynamic sections, then output them. */
2212 if (dynobj != NULL)
2213 {
2214 if (! (*bed->elf_backend_finish_dynamic_sections) (abfd, info))
2215 goto error_return;
2216
2217 for (o = dynobj->sections; o != NULL; o = o->next)
2218 {
2219 if ((o->flags & SEC_HAS_CONTENTS) == 0
2220 || o->_raw_size == 0)
2221 continue;
2222 if ((o->flags & SEC_IN_MEMORY) == 0)
2223 {
2224 /* At this point, we are only interested in sections
2225 created by elf_link_create_dynamic_sections. FIXME:
2226 This test is fragile. */
2227 continue;
2228 }
2229 if ((elf_section_data (o->output_section)->this_hdr.sh_type
2230 != SHT_STRTAB)
2231 || strcmp (bfd_get_section_name (abfd, o), ".dynstr") != 0)
2232 {
2233 if (! bfd_set_section_contents (abfd, o->output_section,
2234 o->contents, o->output_offset,
2235 o->_raw_size))
2236 goto error_return;
2237 }
2238 else
2239 {
2240 file_ptr off;
2241
2242 /* The contents of the .dynstr section are actually in a
2243 stringtab. */
2244 off = elf_section_data (o->output_section)->this_hdr.sh_offset;
2245 if (bfd_seek (abfd, off, SEEK_SET) != 0
2246 || ! _bfd_stringtab_emit (abfd,
2247 elf_hash_table (info)->dynstr))
2248 goto error_return;
2249 }
2250 }
2251 }
2252
2253 if (finfo.symstrtab != NULL)
2254 _bfd_stringtab_free (finfo.symstrtab);
2255 if (finfo.contents != NULL)
2256 free (finfo.contents);
2257 if (finfo.external_relocs != NULL)
2258 free (finfo.external_relocs);
2259 if (finfo.internal_relocs != NULL)
2260 free (finfo.internal_relocs);
2261 if (finfo.external_syms != NULL)
2262 free (finfo.external_syms);
2263 if (finfo.internal_syms != NULL)
2264 free (finfo.internal_syms);
2265 if (finfo.indices != NULL)
2266 free (finfo.indices);
2267 if (finfo.sections != NULL)
2268 free (finfo.sections);
2269 if (finfo.symbuf != NULL)
2270 free (finfo.symbuf);
2271 for (o = abfd->sections; o != NULL; o = o->next)
2272 {
2273 if ((o->flags & SEC_RELOC) != 0
2274 && elf_section_data (o)->rel_hashes != NULL)
2275 free (elf_section_data (o)->rel_hashes);
2276 }
2277
2278 elf_tdata (abfd)->linker = true;
2279
2280 return true;
2281
2282 error_return:
2283 if (finfo.symstrtab != NULL)
2284 _bfd_stringtab_free (finfo.symstrtab);
2285 if (finfo.contents != NULL)
2286 free (finfo.contents);
2287 if (finfo.external_relocs != NULL)
2288 free (finfo.external_relocs);
2289 if (finfo.internal_relocs != NULL)
2290 free (finfo.internal_relocs);
2291 if (finfo.external_syms != NULL)
2292 free (finfo.external_syms);
2293 if (finfo.internal_syms != NULL)
2294 free (finfo.internal_syms);
2295 if (finfo.indices != NULL)
2296 free (finfo.indices);
2297 if (finfo.sections != NULL)
2298 free (finfo.sections);
2299 if (finfo.symbuf != NULL)
2300 free (finfo.symbuf);
2301 for (o = abfd->sections; o != NULL; o = o->next)
2302 {
2303 if ((o->flags & SEC_RELOC) != 0
2304 && elf_section_data (o)->rel_hashes != NULL)
2305 free (elf_section_data (o)->rel_hashes);
2306 }
2307
2308 return false;
2309 }
2310
2311 /* Add a symbol to the output symbol table. */
2312
2313 static boolean
2314 elf_link_output_sym (finfo, name, elfsym, input_sec)
2315 struct elf_final_link_info *finfo;
2316 const char *name;
2317 Elf_Internal_Sym *elfsym;
2318 asection *input_sec;
2319 {
2320 boolean (*output_symbol_hook) PARAMS ((bfd *,
2321 struct bfd_link_info *info,
2322 const char *,
2323 Elf_Internal_Sym *,
2324 asection *));
2325
2326 output_symbol_hook = get_elf_backend_data (finfo->output_bfd)->
2327 elf_backend_link_output_symbol_hook;
2328 if (output_symbol_hook != NULL)
2329 {
2330 if (! ((*output_symbol_hook)
2331 (finfo->output_bfd, finfo->info, name, elfsym, input_sec)))
2332 return false;
2333 }
2334
2335 if (name == (const char *) NULL || *name == '\0')
2336 elfsym->st_name = 0;
2337 else
2338 {
2339 elfsym->st_name = (unsigned long) _bfd_stringtab_add (finfo->symstrtab,
2340 name, true,
2341 false);
2342 if (elfsym->st_name == (unsigned long) -1)
2343 return false;
2344 }
2345
2346 if (finfo->symbuf_count >= finfo->symbuf_size)
2347 {
2348 if (! elf_link_flush_output_syms (finfo))
2349 return false;
2350 }
2351
2352 elf_swap_symbol_out (finfo->output_bfd, elfsym,
2353 (PTR) (finfo->symbuf + finfo->symbuf_count));
2354 ++finfo->symbuf_count;
2355
2356 ++finfo->output_bfd->symcount;
2357
2358 return true;
2359 }
2360
2361 /* Flush the output symbols to the file. */
2362
2363 static boolean
2364 elf_link_flush_output_syms (finfo)
2365 struct elf_final_link_info *finfo;
2366 {
2367 Elf_Internal_Shdr *symtab;
2368
2369 symtab = &elf_tdata (finfo->output_bfd)->symtab_hdr;
2370
2371 if (bfd_seek (finfo->output_bfd, symtab->sh_offset + symtab->sh_size,
2372 SEEK_SET) != 0
2373 || (bfd_write ((PTR) finfo->symbuf, finfo->symbuf_count,
2374 sizeof (Elf_External_Sym), finfo->output_bfd)
2375 != finfo->symbuf_count * sizeof (Elf_External_Sym)))
2376 return false;
2377
2378 symtab->sh_size += finfo->symbuf_count * sizeof (Elf_External_Sym);
2379
2380 finfo->symbuf_count = 0;
2381
2382 return true;
2383 }
2384
2385 /* Add an external symbol to the symbol table. This is called from
2386 the hash table traversal routine. */
2387
2388 static boolean
2389 elf_link_output_extsym (h, data)
2390 struct elf_link_hash_entry *h;
2391 PTR data;
2392 {
2393 struct elf_finfo_failed *eif = (struct elf_finfo_failed *) data;
2394 struct elf_final_link_info *finfo = eif->finfo;
2395 boolean strip;
2396 Elf_Internal_Sym sym;
2397 asection *input_sec;
2398
2399 /* If we are not creating a shared library, and this symbol is
2400 referenced by a shared library but is not defined anywhere, then
2401 warn that it is undefined. If we do not do this, the runtime
2402 linker will complain that the symbol is undefined when the
2403 program is run. We don't have to worry about symbols that are
2404 referenced by regular files, because we will already have issued
2405 warnings for them. */
2406 if (! finfo->info->relocateable
2407 && ! finfo->info->shared
2408 && h->root.type == bfd_link_hash_undefined
2409 && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) != 0
2410 && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) == 0)
2411 {
2412 if (! ((*finfo->info->callbacks->undefined_symbol)
2413 (finfo->info, h->root.root.string, h->root.u.undef.abfd,
2414 (asection *) NULL, 0)))
2415 {
2416 eif->failed = true;
2417 return false;
2418 }
2419 }
2420
2421 /* We don't want to output symbols that have never been mentioned by
2422 a regular file, or that we have been told to strip. However, if
2423 h->indx is set to -2, the symbol is used by a reloc and we must
2424 output it. */
2425 if (h->indx == -2)
2426 strip = false;
2427 else if (((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0
2428 || (h->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) != 0)
2429 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0
2430 && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) == 0)
2431 strip = true;
2432 else if (finfo->info->strip == strip_all
2433 || (finfo->info->strip == strip_some
2434 && bfd_hash_lookup (finfo->info->keep_hash,
2435 h->root.root.string,
2436 false, false) == NULL))
2437 strip = true;
2438 else
2439 strip = false;
2440
2441 /* If we're stripping it, and it's not a dynamic symbol, there's
2442 nothing else to do. */
2443 if (strip && h->dynindx == -1)
2444 return true;
2445
2446 sym.st_value = 0;
2447 sym.st_size = h->size;
2448 sym.st_other = 0;
2449 if (h->root.type == bfd_link_hash_undefweak
2450 || h->root.type == bfd_link_hash_defweak)
2451 sym.st_info = ELF_ST_INFO (STB_WEAK, h->type);
2452 else
2453 sym.st_info = ELF_ST_INFO (STB_GLOBAL, h->type);
2454
2455 switch (h->root.type)
2456 {
2457 default:
2458 case bfd_link_hash_new:
2459 abort ();
2460 return false;
2461
2462 case bfd_link_hash_undefined:
2463 input_sec = bfd_und_section_ptr;
2464 sym.st_shndx = SHN_UNDEF;
2465 break;
2466
2467 case bfd_link_hash_undefweak:
2468 input_sec = bfd_und_section_ptr;
2469 sym.st_shndx = SHN_UNDEF;
2470 break;
2471
2472 case bfd_link_hash_defined:
2473 case bfd_link_hash_defweak:
2474 {
2475 input_sec = h->root.u.def.section;
2476 if (input_sec->output_section != NULL)
2477 {
2478 sym.st_shndx =
2479 _bfd_elf_section_from_bfd_section (finfo->output_bfd,
2480 input_sec->output_section);
2481 if (sym.st_shndx == (unsigned short) -1)
2482 {
2483 eif->failed = true;
2484 return false;
2485 }
2486
2487 /* ELF symbols in relocateable files are section relative,
2488 but in nonrelocateable files they are virtual
2489 addresses. */
2490 sym.st_value = h->root.u.def.value + input_sec->output_offset;
2491 if (! finfo->info->relocateable)
2492 sym.st_value += input_sec->output_section->vma;
2493 }
2494 else
2495 {
2496 BFD_ASSERT ((bfd_get_flavour (input_sec->owner)
2497 == bfd_target_elf_flavour)
2498 && elf_elfheader (input_sec->owner)->e_type == ET_DYN);
2499 sym.st_shndx = SHN_UNDEF;
2500 input_sec = bfd_und_section_ptr;
2501 }
2502 }
2503 break;
2504
2505 case bfd_link_hash_common:
2506 input_sec = bfd_com_section_ptr;
2507 sym.st_shndx = SHN_COMMON;
2508 sym.st_value = 1 << h->root.u.c.p->alignment_power;
2509 break;
2510
2511 case bfd_link_hash_indirect:
2512 case bfd_link_hash_warning:
2513 /* We can't represent these symbols in ELF. A warning symbol
2514 may have come from a .gnu.warning.SYMBOL section anyhow. We
2515 just put the target symbol in the hash table. If the target
2516 symbol does not really exist, don't do anything. */
2517 if (h->root.u.i.link->type == bfd_link_hash_new)
2518 return true;
2519 return (elf_link_output_extsym
2520 ((struct elf_link_hash_entry *) h->root.u.i.link, data));
2521 }
2522
2523 /* If this symbol should be put in the .dynsym section, then put it
2524 there now. We have already know the symbol index. We also fill
2525 in the entry in the .hash section. */
2526 if (h->dynindx != -1
2527 && elf_hash_table (finfo->info)->dynamic_sections_created)
2528 {
2529 struct elf_backend_data *bed;
2530 size_t bucketcount;
2531 size_t bucket;
2532 bfd_byte *bucketpos;
2533 bfd_vma chain;
2534
2535 sym.st_name = h->dynstr_index;
2536
2537 /* Give the processor backend a chance to tweak the symbol
2538 value, and also to finish up anything that needs to be done
2539 for this symbol. */
2540 bed = get_elf_backend_data (finfo->output_bfd);
2541 if (! ((*bed->elf_backend_finish_dynamic_symbol)
2542 (finfo->output_bfd, finfo->info, h, &sym)))
2543 {
2544 eif->failed = true;
2545 return false;
2546 }
2547
2548 elf_swap_symbol_out (finfo->output_bfd, &sym,
2549 (PTR) (((Elf_External_Sym *)
2550 finfo->dynsym_sec->contents)
2551 + h->dynindx));
2552
2553 bucketcount = elf_hash_table (finfo->info)->bucketcount;
2554 bucket = (bfd_elf_hash ((const unsigned char *) h->root.root.string)
2555 % bucketcount);
2556 bucketpos = ((bfd_byte *) finfo->hash_sec->contents
2557 + (bucket + 2) * (ARCH_SIZE / 8));
2558 chain = get_word (finfo->output_bfd, bucketpos);
2559 put_word (finfo->output_bfd, h->dynindx, bucketpos);
2560 put_word (finfo->output_bfd, chain,
2561 ((bfd_byte *) finfo->hash_sec->contents
2562 + (bucketcount + 2 + h->dynindx) * (ARCH_SIZE / 8)));
2563 }
2564
2565 /* If we're stripping it, then it was just a dynamic symbol, and
2566 there's nothing else to do. */
2567 if (strip)
2568 return true;
2569
2570 h->indx = finfo->output_bfd->symcount;
2571
2572 if (! elf_link_output_sym (finfo, h->root.root.string, &sym, input_sec))
2573 {
2574 eif->failed = true;
2575 return false;
2576 }
2577
2578 return true;
2579 }
2580
2581 /* Link an input file into the linker output file. This function
2582 handles all the sections and relocations of the input file at once.
2583 This is so that we only have to read the local symbols once, and
2584 don't have to keep them in memory. */
2585
2586 static boolean
2587 elf_link_input_bfd (finfo, input_bfd)
2588 struct elf_final_link_info *finfo;
2589 bfd *input_bfd;
2590 {
2591 boolean (*relocate_section) PARAMS ((bfd *, struct bfd_link_info *,
2592 bfd *, asection *, bfd_byte *,
2593 Elf_Internal_Rela *,
2594 Elf_Internal_Sym *, asection **));
2595 bfd *output_bfd;
2596 Elf_Internal_Shdr *symtab_hdr;
2597 size_t locsymcount;
2598 size_t extsymoff;
2599 Elf_External_Sym *esym;
2600 Elf_External_Sym *esymend;
2601 Elf_Internal_Sym *isym;
2602 long *pindex;
2603 asection **ppsection;
2604 asection *o;
2605
2606 output_bfd = finfo->output_bfd;
2607 relocate_section =
2608 get_elf_backend_data (output_bfd)->elf_backend_relocate_section;
2609
2610 /* If this is a dynamic object, we don't want to do anything here:
2611 we don't want the local symbols, and we don't want the section
2612 contents. */
2613 if (elf_elfheader (input_bfd)->e_type == ET_DYN)
2614 return true;
2615
2616 symtab_hdr = &elf_tdata (input_bfd)->symtab_hdr;
2617 if (elf_bad_symtab (input_bfd))
2618 {
2619 locsymcount = symtab_hdr->sh_size / sizeof (Elf_External_Sym);
2620 extsymoff = 0;
2621 }
2622 else
2623 {
2624 locsymcount = symtab_hdr->sh_info;
2625 extsymoff = symtab_hdr->sh_info;
2626 }
2627
2628 /* Read the local symbols. */
2629 if (locsymcount > 0
2630 && (bfd_seek (input_bfd, symtab_hdr->sh_offset, SEEK_SET) != 0
2631 || (bfd_read (finfo->external_syms, sizeof (Elf_External_Sym),
2632 locsymcount, input_bfd)
2633 != locsymcount * sizeof (Elf_External_Sym))))
2634 return false;
2635
2636 /* Swap in the local symbols and write out the ones which we know
2637 are going into the output file. */
2638 esym = finfo->external_syms;
2639 esymend = esym + locsymcount;
2640 isym = finfo->internal_syms;
2641 pindex = finfo->indices;
2642 ppsection = finfo->sections;
2643 for (; esym < esymend; esym++, isym++, pindex++, ppsection++)
2644 {
2645 asection *isec;
2646 const char *name;
2647 Elf_Internal_Sym osym;
2648
2649 elf_swap_symbol_in (input_bfd, esym, isym);
2650 *pindex = -1;
2651
2652 if (elf_bad_symtab (input_bfd))
2653 {
2654 if (ELF_ST_BIND (isym->st_info) != STB_LOCAL)
2655 {
2656 *ppsection = NULL;
2657 continue;
2658 }
2659 }
2660
2661 if (isym->st_shndx == SHN_UNDEF)
2662 isec = bfd_und_section_ptr;
2663 else if (isym->st_shndx > 0 && isym->st_shndx < SHN_LORESERVE)
2664 isec = section_from_elf_index (input_bfd, isym->st_shndx);
2665 else if (isym->st_shndx == SHN_ABS)
2666 isec = bfd_abs_section_ptr;
2667 else if (isym->st_shndx == SHN_COMMON)
2668 isec = bfd_com_section_ptr;
2669 else
2670 {
2671 /* Who knows? */
2672 isec = NULL;
2673 }
2674
2675 *ppsection = isec;
2676
2677 /* Don't output the first, undefined, symbol. */
2678 if (esym == finfo->external_syms)
2679 continue;
2680
2681 /* If we are stripping all symbols, we don't want to output this
2682 one. */
2683 if (finfo->info->strip == strip_all)
2684 continue;
2685
2686 /* We never output section symbols. Instead, we use the section
2687 symbol of the corresponding section in the output file. */
2688 if (ELF_ST_TYPE (isym->st_info) == STT_SECTION)
2689 continue;
2690
2691 /* If we are discarding all local symbols, we don't want to
2692 output this one. If we are generating a relocateable output
2693 file, then some of the local symbols may be required by
2694 relocs; we output them below as we discover that they are
2695 needed. */
2696 if (finfo->info->discard == discard_all)
2697 continue;
2698
2699 /* Get the name of the symbol. */
2700 name = bfd_elf_string_from_elf_section (input_bfd, symtab_hdr->sh_link,
2701 isym->st_name);
2702 if (name == NULL)
2703 return false;
2704
2705 /* See if we are discarding symbols with this name. */
2706 if ((finfo->info->strip == strip_some
2707 && (bfd_hash_lookup (finfo->info->keep_hash, name, false, false)
2708 == NULL))
2709 || (finfo->info->discard == discard_l
2710 && strncmp (name, finfo->info->lprefix,
2711 finfo->info->lprefix_len) == 0))
2712 continue;
2713
2714 /* If we get here, we are going to output this symbol. */
2715
2716 osym = *isym;
2717
2718 /* Adjust the section index for the output file. */
2719 osym.st_shndx = _bfd_elf_section_from_bfd_section (output_bfd,
2720 isec->output_section);
2721 if (osym.st_shndx == (unsigned short) -1)
2722 return false;
2723
2724 *pindex = output_bfd->symcount;
2725
2726 /* ELF symbols in relocateable files are section relative, but
2727 in executable files they are virtual addresses. Note that
2728 this code assumes that all ELF sections have an associated
2729 BFD section with a reasonable value for output_offset; below
2730 we assume that they also have a reasonable value for
2731 output_section. Any special sections must be set up to meet
2732 these requirements. */
2733 osym.st_value += isec->output_offset;
2734 if (! finfo->info->relocateable)
2735 osym.st_value += isec->output_section->vma;
2736
2737 if (! elf_link_output_sym (finfo, name, &osym, isec))
2738 return false;
2739 }
2740
2741 /* Relocate the contents of each section. */
2742 for (o = input_bfd->sections; o != NULL; o = o->next)
2743 {
2744 if ((o->flags & SEC_HAS_CONTENTS) == 0)
2745 continue;
2746
2747 if ((o->flags & SEC_IN_MEMORY) != 0
2748 && input_bfd == elf_hash_table (finfo->info)->dynobj)
2749 {
2750 /* Section was created by elf_link_create_dynamic_sections.
2751 FIXME: This test is fragile. */
2752 continue;
2753 }
2754
2755 /* Read the contents of the section. */
2756 if (! bfd_get_section_contents (input_bfd, o, finfo->contents,
2757 (file_ptr) 0, o->_raw_size))
2758 return false;
2759
2760 if ((o->flags & SEC_RELOC) != 0)
2761 {
2762 Elf_Internal_Rela *internal_relocs;
2763
2764 /* Get the swapped relocs. */
2765 internal_relocs = elf_link_read_relocs (input_bfd, o,
2766 finfo->external_relocs,
2767 finfo->internal_relocs,
2768 false);
2769 if (internal_relocs == NULL
2770 && o->reloc_count > 0)
2771 return false;
2772
2773 /* Relocate the section by invoking a back end routine.
2774
2775 The back end routine is responsible for adjusting the
2776 section contents as necessary, and (if using Rela relocs
2777 and generating a relocateable output file) adjusting the
2778 reloc addend as necessary.
2779
2780 The back end routine does not have to worry about setting
2781 the reloc address or the reloc symbol index.
2782
2783 The back end routine is given a pointer to the swapped in
2784 internal symbols, and can access the hash table entries
2785 for the external symbols via elf_sym_hashes (input_bfd).
2786
2787 When generating relocateable output, the back end routine
2788 must handle STB_LOCAL/STT_SECTION symbols specially. The
2789 output symbol is going to be a section symbol
2790 corresponding to the output section, which will require
2791 the addend to be adjusted. */
2792
2793 if (! (*relocate_section) (output_bfd, finfo->info,
2794 input_bfd, o,
2795 finfo->contents,
2796 internal_relocs,
2797 finfo->internal_syms,
2798 finfo->sections))
2799 return false;
2800
2801 if (finfo->info->relocateable)
2802 {
2803 Elf_Internal_Rela *irela;
2804 Elf_Internal_Rela *irelaend;
2805 struct elf_link_hash_entry **rel_hash;
2806 Elf_Internal_Shdr *input_rel_hdr;
2807 Elf_Internal_Shdr *output_rel_hdr;
2808
2809 /* Adjust the reloc addresses and symbol indices. */
2810
2811 irela = internal_relocs;
2812 irelaend = irela + o->reloc_count;
2813 rel_hash = (elf_section_data (o->output_section)->rel_hashes
2814 + o->output_section->reloc_count);
2815 for (; irela < irelaend; irela++, rel_hash++)
2816 {
2817 unsigned long r_symndx;
2818 Elf_Internal_Sym *isym;
2819 asection *sec;
2820
2821 irela->r_offset += o->output_offset;
2822
2823 r_symndx = ELF_R_SYM (irela->r_info);
2824
2825 if (r_symndx == 0)
2826 continue;
2827
2828 if (r_symndx >= locsymcount
2829 || (elf_bad_symtab (input_bfd)
2830 && finfo->sections[r_symndx] == NULL))
2831 {
2832 long indx;
2833
2834 /* This is a reloc against a global symbol. We
2835 have not yet output all the local symbols, so
2836 we do not know the symbol index of any global
2837 symbol. We set the rel_hash entry for this
2838 reloc to point to the global hash table entry
2839 for this symbol. The symbol index is then
2840 set at the end of elf_bfd_final_link. */
2841 indx = r_symndx - extsymoff;
2842 *rel_hash = elf_sym_hashes (input_bfd)[indx];
2843
2844 /* Setting the index to -2 tells
2845 elf_link_output_extsym that this symbol is
2846 used by a reloc. */
2847 BFD_ASSERT ((*rel_hash)->indx < 0);
2848 (*rel_hash)->indx = -2;
2849
2850 continue;
2851 }
2852
2853 /* This is a reloc against a local symbol. */
2854
2855 *rel_hash = NULL;
2856 isym = finfo->internal_syms + r_symndx;
2857 sec = finfo->sections[r_symndx];
2858 if (ELF_ST_TYPE (isym->st_info) == STT_SECTION)
2859 {
2860 /* I suppose the backend ought to fill in the
2861 section of any STT_SECTION symbol against a
2862 processor specific section. */
2863 if (sec != NULL && bfd_is_abs_section (sec))
2864 r_symndx = 0;
2865 else if (sec == NULL || sec->owner == NULL)
2866 {
2867 bfd_set_error (bfd_error_bad_value);
2868 return false;
2869 }
2870 else
2871 {
2872 r_symndx = sec->output_section->target_index;
2873 BFD_ASSERT (r_symndx != 0);
2874 }
2875 }
2876 else
2877 {
2878 if (finfo->indices[r_symndx] == -1)
2879 {
2880 unsigned long link;
2881 const char *name;
2882 asection *osec;
2883
2884 if (finfo->info->strip == strip_all)
2885 {
2886 /* You can't do ld -r -s. */
2887 bfd_set_error (bfd_error_invalid_operation);
2888 return false;
2889 }
2890
2891 /* This symbol was skipped earlier, but
2892 since it is needed by a reloc, we
2893 must output it now. */
2894 link = symtab_hdr->sh_link;
2895 name = bfd_elf_string_from_elf_section (input_bfd,
2896 link,
2897 isym->st_name);
2898 if (name == NULL)
2899 return false;
2900
2901 osec = sec->output_section;
2902 isym->st_shndx =
2903 _bfd_elf_section_from_bfd_section (output_bfd,
2904 osec);
2905 if (isym->st_shndx == (unsigned short) -1)
2906 return false;
2907
2908 isym->st_value += sec->output_offset;
2909 if (! finfo->info->relocateable)
2910 isym->st_value += osec->vma;
2911
2912 finfo->indices[r_symndx] = output_bfd->symcount;
2913
2914 if (! elf_link_output_sym (finfo, name, isym, sec))
2915 return false;
2916 }
2917
2918 r_symndx = finfo->indices[r_symndx];
2919 }
2920
2921 irela->r_info = ELF_R_INFO (r_symndx,
2922 ELF_R_TYPE (irela->r_info));
2923 }
2924
2925 /* Swap out the relocs. */
2926 input_rel_hdr = &elf_section_data (o)->rel_hdr;
2927 output_rel_hdr = &elf_section_data (o->output_section)->rel_hdr;
2928 BFD_ASSERT (output_rel_hdr->sh_entsize
2929 == input_rel_hdr->sh_entsize);
2930 irela = internal_relocs;
2931 irelaend = irela + o->reloc_count;
2932 if (input_rel_hdr->sh_entsize == sizeof (Elf_External_Rel))
2933 {
2934 Elf_External_Rel *erel;
2935
2936 erel = ((Elf_External_Rel *) output_rel_hdr->contents
2937 + o->output_section->reloc_count);
2938 for (; irela < irelaend; irela++, erel++)
2939 {
2940 Elf_Internal_Rel irel;
2941
2942 irel.r_offset = irela->r_offset;
2943 irel.r_info = irela->r_info;
2944 BFD_ASSERT (irela->r_addend == 0);
2945 elf_swap_reloc_out (output_bfd, &irel, erel);
2946 }
2947 }
2948 else
2949 {
2950 Elf_External_Rela *erela;
2951
2952 BFD_ASSERT (input_rel_hdr->sh_entsize
2953 == sizeof (Elf_External_Rela));
2954 erela = ((Elf_External_Rela *) output_rel_hdr->contents
2955 + o->output_section->reloc_count);
2956 for (; irela < irelaend; irela++, erela++)
2957 elf_swap_reloca_out (output_bfd, irela, erela);
2958 }
2959
2960 o->output_section->reloc_count += o->reloc_count;
2961 }
2962 }
2963
2964 /* Write out the modified section contents. */
2965 if (! bfd_set_section_contents (output_bfd, o->output_section,
2966 finfo->contents, o->output_offset,
2967 (o->_cooked_size != 0
2968 ? o->_cooked_size
2969 : o->_raw_size)))
2970 return false;
2971 }
2972
2973 return true;
2974 }
2975
2976 /* Generate a reloc when linking an ELF file. This is a reloc
2977 requested by the linker, and does come from any input file. This
2978 is used to build constructor and destructor tables when linking
2979 with -Ur. */
2980
2981 static boolean
2982 elf_reloc_link_order (output_bfd, info, output_section, link_order)
2983 bfd *output_bfd;
2984 struct bfd_link_info *info;
2985 asection *output_section;
2986 struct bfd_link_order *link_order;
2987 {
2988 reloc_howto_type *howto;
2989 long indx;
2990 bfd_vma offset;
2991 bfd_vma addend;
2992 struct elf_link_hash_entry **rel_hash_ptr;
2993 Elf_Internal_Shdr *rel_hdr;
2994
2995 howto = bfd_reloc_type_lookup (output_bfd, link_order->u.reloc.p->reloc);
2996 if (howto == NULL)
2997 {
2998 bfd_set_error (bfd_error_bad_value);
2999 return false;
3000 }
3001
3002 addend = link_order->u.reloc.p->addend;
3003
3004 /* Figure out the symbol index. */
3005 rel_hash_ptr = (elf_section_data (output_section)->rel_hashes
3006 + output_section->reloc_count);
3007 if (link_order->type == bfd_section_reloc_link_order)
3008 {
3009 indx = link_order->u.reloc.p->u.section->target_index;
3010 BFD_ASSERT (indx != 0);
3011 *rel_hash_ptr = NULL;
3012 }
3013 else
3014 {
3015 struct elf_link_hash_entry *h;
3016
3017 /* Treat a reloc against a defined symbol as though it were
3018 actually against the section. */
3019 h = elf_link_hash_lookup (elf_hash_table (info),
3020 link_order->u.reloc.p->u.name,
3021 false, false, true);
3022 if (h != NULL
3023 && (h->root.type == bfd_link_hash_defined
3024 || h->root.type == bfd_link_hash_defweak))
3025 {
3026 asection *section;
3027
3028 section = h->root.u.def.section;
3029 indx = section->output_section->target_index;
3030 *rel_hash_ptr = NULL;
3031 /* It seems that we ought to add the symbol value to the
3032 addend here, but in practice it has already been added
3033 because it was passed to constructor_callback. */
3034 addend += section->output_section->vma + section->output_offset;
3035 }
3036 else if (h != NULL)
3037 {
3038 /* Setting the index to -2 tells elf_link_output_extsym that
3039 this symbol is used by a reloc. */
3040 h->indx = -2;
3041 *rel_hash_ptr = h;
3042 indx = 0;
3043 }
3044 else
3045 {
3046 if (! ((*info->callbacks->unattached_reloc)
3047 (info, link_order->u.reloc.p->u.name, (bfd *) NULL,
3048 (asection *) NULL, (bfd_vma) 0)))
3049 return false;
3050 indx = 0;
3051 }
3052 }
3053
3054 /* If this is an inplace reloc, we must write the addend into the
3055 object file. */
3056 if (howto->partial_inplace && addend != 0)
3057 {
3058 bfd_size_type size;
3059 bfd_reloc_status_type rstat;
3060 bfd_byte *buf;
3061 boolean ok;
3062
3063 size = bfd_get_reloc_size (howto);
3064 buf = (bfd_byte *) bfd_zmalloc (size);
3065 if (buf == (bfd_byte *) NULL)
3066 return false;
3067 rstat = _bfd_relocate_contents (howto, output_bfd, addend, buf);
3068 switch (rstat)
3069 {
3070 case bfd_reloc_ok:
3071 break;
3072 default:
3073 case bfd_reloc_outofrange:
3074 abort ();
3075 case bfd_reloc_overflow:
3076 if (! ((*info->callbacks->reloc_overflow)
3077 (info,
3078 (link_order->type == bfd_section_reloc_link_order
3079 ? bfd_section_name (output_bfd,
3080 link_order->u.reloc.p->u.section)
3081 : link_order->u.reloc.p->u.name),
3082 howto->name, addend, (bfd *) NULL, (asection *) NULL,
3083 (bfd_vma) 0)))
3084 {
3085 free (buf);
3086 return false;
3087 }
3088 break;
3089 }
3090 ok = bfd_set_section_contents (output_bfd, output_section, (PTR) buf,
3091 (file_ptr) link_order->offset, size);
3092 free (buf);
3093 if (! ok)
3094 return false;
3095 }
3096
3097 /* The address of a reloc is relative to the section in a
3098 relocateable file, and is a virtual address in an executable
3099 file. */
3100 offset = link_order->offset;
3101 if (! info->relocateable)
3102 offset += output_section->vma;
3103
3104 rel_hdr = &elf_section_data (output_section)->rel_hdr;
3105
3106 if (rel_hdr->sh_type == SHT_REL)
3107 {
3108 Elf_Internal_Rel irel;
3109 Elf_External_Rel *erel;
3110
3111 irel.r_offset = offset;
3112 irel.r_info = ELF_R_INFO (indx, howto->type);
3113 erel = ((Elf_External_Rel *) rel_hdr->contents
3114 + output_section->reloc_count);
3115 elf_swap_reloc_out (output_bfd, &irel, erel);
3116 }
3117 else
3118 {
3119 Elf_Internal_Rela irela;
3120 Elf_External_Rela *erela;
3121
3122 irela.r_offset = offset;
3123 irela.r_info = ELF_R_INFO (indx, howto->type);
3124 irela.r_addend = addend;
3125 erela = ((Elf_External_Rela *) rel_hdr->contents
3126 + output_section->reloc_count);
3127 elf_swap_reloca_out (output_bfd, &irela, erela);
3128 }
3129
3130 ++output_section->reloc_count;
3131
3132 return true;
3133 }
3134