x
[deliverable/binutils-gdb.git] / bfd / elflink.h
1 /* ELF linker support.
2 Copyright 1995 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 *) malloc (c * sizeof (boolean));
114 included = (boolean *) malloc (c * sizeof (boolean));
115 if (defined == (boolean *) NULL || included == (boolean *) NULL)
116 {
117 bfd_set_error (bfd_error_no_memory);
118 goto error_return;
119 }
120 memset (defined, 0, c * sizeof (boolean));
121 memset (included, 0, c * sizeof (boolean));
122
123 symdefs = bfd_ardata (abfd)->symdefs;
124
125 do
126 {
127 file_ptr last;
128 symindex i;
129 carsym *symdef;
130 carsym *symdefend;
131
132 loop = false;
133 last = -1;
134
135 symdef = symdefs;
136 symdefend = symdef + c;
137 for (i = 0; symdef < symdefend; symdef++, i++)
138 {
139 struct elf_link_hash_entry *h;
140 bfd *element;
141 struct bfd_link_hash_entry *undefs_tail;
142 symindex mark;
143
144 if (defined[i] || included[i])
145 continue;
146 if (symdef->file_offset == last)
147 {
148 included[i] = true;
149 continue;
150 }
151
152 h = elf_link_hash_lookup (elf_hash_table (info), symdef->name,
153 false, false, false);
154 if (h == (struct elf_link_hash_entry *) NULL)
155 continue;
156 if (h->root.type != bfd_link_hash_undefined)
157 {
158 if (h->root.type != bfd_link_hash_undefweak)
159 defined[i] = true;
160 continue;
161 }
162
163 /* We need to include this archive member. */
164
165 element = _bfd_get_elt_at_filepos (abfd, symdef->file_offset);
166 if (element == (bfd *) NULL)
167 goto error_return;
168
169 if (! bfd_check_format (element, bfd_object))
170 goto error_return;
171
172 /* Doublecheck that we have not included this object
173 already--it should be impossible, but there may be
174 something wrong with the archive. */
175 if (element->archive_pass != 0)
176 {
177 bfd_set_error (bfd_error_bad_value);
178 goto error_return;
179 }
180 element->archive_pass = 1;
181
182 undefs_tail = info->hash->undefs_tail;
183
184 if (! (*info->callbacks->add_archive_element) (info, element,
185 symdef->name))
186 goto error_return;
187 if (! elf_link_add_object_symbols (element, info))
188 goto error_return;
189
190 /* If there are any new undefined symbols, we need to make
191 another pass through the archive in order to see whether
192 they can be defined. FIXME: This isn't perfect, because
193 common symbols wind up on undefs_tail and because an
194 undefined symbol which is defined later on in this pass
195 does not require another pass. This isn't a bug, but it
196 does make the code less efficient than it could be. */
197 if (undefs_tail != info->hash->undefs_tail)
198 loop = true;
199
200 /* Look backward to mark all symbols from this object file
201 which we have already seen in this pass. */
202 mark = i;
203 do
204 {
205 included[mark] = true;
206 if (mark == 0)
207 break;
208 --mark;
209 }
210 while (symdefs[mark].file_offset == symdef->file_offset);
211
212 /* We mark subsequent symbols from this object file as we go
213 on through the loop. */
214 last = symdef->file_offset;
215 }
216 }
217 while (loop);
218
219 free (defined);
220 free (included);
221
222 return true;
223
224 error_return:
225 if (defined != (boolean *) NULL)
226 free (defined);
227 if (included != (boolean *) NULL)
228 free (included);
229 return false;
230 }
231
232 /* Add symbols from an ELF object file to the linker hash table. */
233
234 static boolean
235 elf_link_add_object_symbols (abfd, info)
236 bfd *abfd;
237 struct bfd_link_info *info;
238 {
239 boolean (*add_symbol_hook) PARAMS ((bfd *, struct bfd_link_info *,
240 const Elf_Internal_Sym *,
241 const char **, flagword *,
242 asection **, bfd_vma *));
243 boolean (*check_relocs) PARAMS ((bfd *, struct bfd_link_info *,
244 asection *, const Elf_Internal_Rela *));
245 boolean collect;
246 Elf_Internal_Shdr *hdr;
247 size_t symcount;
248 size_t extsymcount;
249 size_t extsymoff;
250 Elf_External_Sym *buf = NULL;
251 struct elf_link_hash_entry **sym_hash;
252 boolean dynamic;
253 Elf_External_Dyn *dynbuf = NULL;
254 struct elf_link_hash_entry *weaks;
255 Elf_External_Sym *esym;
256 Elf_External_Sym *esymend;
257
258 add_symbol_hook = get_elf_backend_data (abfd)->elf_add_symbol_hook;
259 collect = get_elf_backend_data (abfd)->collect;
260
261 /* As a GNU extension, any input sections which are named
262 .gnu.warning.SYMBOL are treated as warning symbols for the given
263 symbol. This differs from .gnu.warning sections, which generate
264 warnings when they are included in an output file. */
265 if (! info->shared)
266 {
267 asection *s;
268
269 for (s = abfd->sections; s != NULL; s = s->next)
270 {
271 const char *name;
272
273 name = bfd_get_section_name (abfd, s);
274 if (strncmp (name, ".gnu.warning.", sizeof ".gnu.warning." - 1) == 0)
275 {
276 char *msg;
277 bfd_size_type sz;
278
279 sz = bfd_section_size (abfd, s);
280 msg = (char *) bfd_alloc (abfd, sz);
281 if (msg == NULL)
282 {
283 bfd_set_error (bfd_error_no_memory);
284 goto error_return;
285 }
286
287 if (! bfd_get_section_contents (abfd, s, msg, (file_ptr) 0, sz))
288 goto error_return;
289
290 if (! (_bfd_generic_link_add_one_symbol
291 (info, abfd,
292 name + sizeof ".gnu.warning." - 1,
293 BSF_WARNING, s, (bfd_vma) 0, msg, false, collect,
294 (struct bfd_link_hash_entry **) NULL)))
295 goto error_return;
296
297 if (! info->relocateable)
298 {
299 /* Clobber the section size so that the warning does
300 not get copied into the output file. */
301 s->_raw_size = 0;
302 }
303 }
304 }
305 }
306
307 /* A stripped shared library might only have a dynamic symbol table,
308 not a regular symbol table. In that case we can still go ahead
309 and link using the dynamic symbol table. */
310 if (elf_onesymtab (abfd) == 0
311 && elf_dynsymtab (abfd) != 0)
312 {
313 elf_onesymtab (abfd) = elf_dynsymtab (abfd);
314 elf_tdata (abfd)->symtab_hdr = elf_tdata (abfd)->dynsymtab_hdr;
315 }
316
317 hdr = &elf_tdata (abfd)->symtab_hdr;
318 symcount = hdr->sh_size / sizeof (Elf_External_Sym);
319
320 /* The sh_info field of the symtab header tells us where the
321 external symbols start. We don't care about the local symbols at
322 this point. */
323 if (elf_bad_symtab (abfd))
324 {
325 extsymcount = symcount;
326 extsymoff = 0;
327 }
328 else
329 {
330 extsymcount = symcount - hdr->sh_info;
331 extsymoff = hdr->sh_info;
332 }
333
334 buf = (Elf_External_Sym *) malloc (extsymcount * sizeof (Elf_External_Sym));
335 if (buf == NULL && extsymcount != 0)
336 {
337 bfd_set_error (bfd_error_no_memory);
338 goto error_return;
339 }
340
341 /* We store a pointer to the hash table entry for each external
342 symbol. */
343 sym_hash = ((struct elf_link_hash_entry **)
344 bfd_alloc (abfd,
345 extsymcount * sizeof (struct elf_link_hash_entry *)));
346 if (sym_hash == NULL)
347 {
348 bfd_set_error (bfd_error_no_memory);
349 goto error_return;
350 }
351 elf_sym_hashes (abfd) = sym_hash;
352
353 if (elf_elfheader (abfd)->e_type != ET_DYN)
354 {
355 dynamic = false;
356
357 /* If we are creating a shared library, create all the dynamic
358 sections immediately. We need to attach them to something,
359 so we attach them to this BFD, provided it is the right
360 format. FIXME: If there are no input BFD's of the same
361 format as the output, we can't make a shared library. */
362 if (info->shared
363 && ! elf_hash_table (info)->dynamic_sections_created
364 && abfd->xvec == info->hash->creator)
365 {
366 if (! elf_link_create_dynamic_sections (abfd, info))
367 goto error_return;
368 }
369 }
370 else
371 {
372 asection *s;
373 boolean add_needed;
374 const char *name;
375 bfd_size_type oldsize;
376 bfd_size_type strindex;
377
378 dynamic = true;
379
380 /* You can't use -r against a dynamic object. Also, there's no
381 hope of using a dynamic object which does not exactly match
382 the format of the output file. */
383 if (info->relocateable
384 || info->hash->creator != abfd->xvec)
385 {
386 bfd_set_error (bfd_error_invalid_operation);
387 goto error_return;
388 }
389
390 /* Find the name to use in a DT_NEEDED entry that refers to this
391 object. If the object has a DT_SONAME entry, we use it.
392 Otherwise, if the generic linker stuck something in
393 elf_dt_needed_name, we use that. Otherwise, we just use the
394 file name. If the generic linker put a null string into
395 elf_dt_needed_name, we don't make a DT_NEEDED entry at all,
396 even if there is a DT_SONAME entry. */
397 add_needed = true;
398 name = bfd_get_filename (abfd);
399 if (elf_dt_needed_name (abfd) != NULL)
400 {
401 name = elf_dt_needed_name (abfd);
402 if (*name == '\0')
403 add_needed = false;
404 }
405 s = bfd_get_section_by_name (abfd, ".dynamic");
406 if (s != NULL)
407 {
408 Elf_External_Dyn *extdyn;
409 Elf_External_Dyn *extdynend;
410 int elfsec;
411 unsigned long link;
412
413 dynbuf = (Elf_External_Dyn *) malloc ((size_t) s->_raw_size);
414 if (dynbuf == NULL)
415 {
416 bfd_set_error (bfd_error_no_memory);
417 goto error_return;
418 }
419
420 if (! bfd_get_section_contents (abfd, s, (PTR) dynbuf,
421 (file_ptr) 0, s->_raw_size))
422 goto error_return;
423
424 elfsec = _bfd_elf_section_from_bfd_section (abfd, s);
425 if (elfsec == -1)
426 goto error_return;
427 link = elf_elfsections (abfd)[elfsec]->sh_link;
428
429 extdyn = dynbuf;
430 extdynend = extdyn + s->_raw_size / sizeof (Elf_External_Dyn);
431 for (; extdyn < extdynend; extdyn++)
432 {
433 Elf_Internal_Dyn dyn;
434
435 elf_swap_dyn_in (abfd, extdyn, &dyn);
436 if (add_needed && dyn.d_tag == DT_SONAME)
437 {
438 name = bfd_elf_string_from_elf_section (abfd, link,
439 dyn.d_un.d_val);
440 if (name == NULL)
441 goto error_return;
442 }
443 if (dyn.d_tag == DT_NEEDED)
444 {
445 struct bfd_elf_link_needed_list *n, **pn;
446 char *fnm, *anm;
447
448 n = (struct bfd_elf_link_needed_list *)
449 bfd_alloc (abfd,
450 sizeof (struct bfd_elf_link_needed_list));
451 fnm = bfd_elf_string_from_elf_section (abfd, link,
452 dyn.d_un.d_val);
453 if (n == NULL || fnm == NULL)
454 goto error_return;
455 anm = bfd_alloc (abfd, strlen (fnm) + 1);
456 if (anm == NULL)
457 goto error_return;
458 strcpy (anm, fnm);
459 n->name = anm;
460 n->by = abfd;
461 n->next = NULL;
462 for (pn = &elf_hash_table (info)->needed;
463 *pn != NULL;
464 pn = &(*pn)->next)
465 ;
466 *pn = n;
467 }
468 }
469
470 free (dynbuf);
471 dynbuf = NULL;
472 }
473
474 /* We do not want to include any of the sections in a dynamic
475 object in the output file. We hack by simply clobbering the
476 list of sections in the BFD. This could be handled more
477 cleanly by, say, a new section flag; the existing
478 SEC_NEVER_LOAD flag is not the one we want, because that one
479 still implies that the section takes up space in the output
480 file. */
481 abfd->sections = NULL;
482
483 /* If this is the first dynamic object found in the link, create
484 the special sections required for dynamic linking. */
485 if (! elf_hash_table (info)->dynamic_sections_created)
486 {
487 if (! elf_link_create_dynamic_sections (abfd, info))
488 goto error_return;
489 }
490
491 if (add_needed)
492 {
493 /* Add a DT_NEEDED entry for this dynamic object. */
494 oldsize = _bfd_stringtab_size (elf_hash_table (info)->dynstr);
495 strindex = _bfd_stringtab_add (elf_hash_table (info)->dynstr, name,
496 true, false);
497 if (strindex == (bfd_size_type) -1)
498 goto error_return;
499
500 if (oldsize == _bfd_stringtab_size (elf_hash_table (info)->dynstr))
501 {
502 asection *sdyn;
503 Elf_External_Dyn *dyncon, *dynconend;
504
505 /* The hash table size did not change, which means that
506 the dynamic object name was already entered. If we
507 have already included this dynamic object in the
508 link, just ignore it. There is no reason to include
509 a particular dynamic object more than once. */
510 sdyn = bfd_get_section_by_name (elf_hash_table (info)->dynobj,
511 ".dynamic");
512 BFD_ASSERT (sdyn != NULL);
513
514 dyncon = (Elf_External_Dyn *) sdyn->contents;
515 dynconend = (Elf_External_Dyn *) (sdyn->contents +
516 sdyn->_raw_size);
517 for (; dyncon < dynconend; dyncon++)
518 {
519 Elf_Internal_Dyn dyn;
520
521 elf_swap_dyn_in (elf_hash_table (info)->dynobj, dyncon,
522 &dyn);
523 if (dyn.d_tag == DT_NEEDED
524 && dyn.d_un.d_val == strindex)
525 {
526 if (buf != NULL)
527 free (buf);
528 return true;
529 }
530 }
531 }
532
533 if (! elf_add_dynamic_entry (info, DT_NEEDED, strindex))
534 goto error_return;
535 }
536 }
537
538 if (bfd_seek (abfd,
539 hdr->sh_offset + extsymoff * sizeof (Elf_External_Sym),
540 SEEK_SET) != 0
541 || (bfd_read ((PTR) buf, sizeof (Elf_External_Sym), extsymcount, abfd)
542 != extsymcount * sizeof (Elf_External_Sym)))
543 goto error_return;
544
545 weaks = NULL;
546
547 esymend = buf + extsymcount;
548 for (esym = buf; esym < esymend; esym++, sym_hash++)
549 {
550 Elf_Internal_Sym sym;
551 int bind;
552 bfd_vma value;
553 asection *sec;
554 flagword flags;
555 const char *name;
556 struct elf_link_hash_entry *h;
557 boolean definition;
558 boolean wasweak;
559 boolean new_weakdef;
560
561 elf_swap_symbol_in (abfd, esym, &sym);
562
563 flags = BSF_NO_FLAGS;
564 sec = NULL;
565 value = sym.st_value;
566 *sym_hash = NULL;
567
568 bind = ELF_ST_BIND (sym.st_info);
569 if (bind == STB_LOCAL)
570 {
571 /* This should be impossible, since ELF requires that all
572 global symbols follow all local symbols, and that sh_info
573 point to the first global symbol. Unfortunatealy, Irix 5
574 screws this up. */
575 continue;
576 }
577 else if (bind == STB_GLOBAL)
578 {
579 if (sym.st_shndx != SHN_UNDEF
580 && sym.st_shndx != SHN_COMMON)
581 flags = BSF_GLOBAL;
582 else
583 flags = 0;
584 }
585 else if (bind == STB_WEAK)
586 flags = BSF_WEAK;
587 else
588 {
589 /* Leave it up to the processor backend. */
590 }
591
592 if (sym.st_shndx == SHN_UNDEF)
593 sec = bfd_und_section_ptr;
594 else if (sym.st_shndx > 0 && sym.st_shndx < SHN_LORESERVE)
595 {
596 sec = section_from_elf_index (abfd, sym.st_shndx);
597 if (sec != NULL)
598 value -= sec->vma;
599 else
600 sec = bfd_abs_section_ptr;
601 }
602 else if (sym.st_shndx == SHN_ABS)
603 sec = bfd_abs_section_ptr;
604 else if (sym.st_shndx == SHN_COMMON)
605 {
606 sec = bfd_com_section_ptr;
607 /* What ELF calls the size we call the value. What ELF
608 calls the value we call the alignment. */
609 value = sym.st_size;
610 }
611 else
612 {
613 /* Leave it up to the processor backend. */
614 }
615
616 name = bfd_elf_string_from_elf_section (abfd, hdr->sh_link, sym.st_name);
617 if (name == (const char *) NULL)
618 goto error_return;
619
620 if (add_symbol_hook)
621 {
622 if (! (*add_symbol_hook) (abfd, info, &sym, &name, &flags, &sec,
623 &value))
624 goto error_return;
625
626 /* The hook function sets the name to NULL if this symbol
627 should be skipped for some reason. */
628 if (name == (const char *) NULL)
629 continue;
630 }
631
632 /* Sanity check that all possibilities were handled. */
633 if (sec == (asection *) NULL)
634 {
635 bfd_set_error (bfd_error_bad_value);
636 goto error_return;
637 }
638
639 if (bfd_is_und_section (sec)
640 || bfd_is_com_section (sec))
641 definition = false;
642 else
643 definition = true;
644
645 wasweak = false;
646 if (info->hash->creator->flavour == bfd_target_elf_flavour)
647 {
648 /* We need to look up the symbol now in order to get some of
649 the dynamic object handling right. We pass the hash
650 table entry in to _bfd_generic_link_add_one_symbol so
651 that it does not have to look it up again. */
652 h = elf_link_hash_lookup (elf_hash_table (info), name,
653 true, false, false);
654 if (h == NULL)
655 goto error_return;
656 *sym_hash = h;
657
658 while (h->root.type == bfd_link_hash_indirect
659 || h->root.type == bfd_link_hash_warning)
660 h = (struct elf_link_hash_entry *) h->root.u.i.link;
661
662 /* Remember whether this used to be a weak definition. */
663 wasweak = (h->root.type == bfd_link_hash_defweak
664 || h->root.type == bfd_link_hash_undefweak);
665
666 /* If we are looking at a dynamic object, and this is a
667 definition, we need to see if it has already been defined
668 by some other object. If it has, we want to use the
669 existing definition, and we do not want to report a
670 multiple symbol definition error; we do this by
671 clobbering sec to be bfd_und_section_ptr. */
672 if (dynamic && definition)
673 {
674 if (h->root.type == bfd_link_hash_defined
675 || h->root.type == bfd_link_hash_defweak
676 || (h->root.type == bfd_link_hash_common
677 && bind == STB_WEAK))
678 {
679 sec = bfd_und_section_ptr;
680 definition = false;
681 }
682 }
683
684 /* Similarly, if we are not looking at a dynamic object, and
685 we have a definition, we want to override any definition
686 we may have from a dynamic object. Symbols from regular
687 files always take precedence over symbols from dynamic
688 objects, even if they are defined after the dynamic
689 object in the link. */
690 if (! dynamic
691 && definition
692 && (h->root.type == bfd_link_hash_defined
693 || h->root.type == bfd_link_hash_defweak)
694 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0
695 && (bfd_get_flavour (h->root.u.def.section->owner)
696 == bfd_target_elf_flavour)
697 && (elf_elfheader (h->root.u.def.section->owner)->e_type
698 == ET_DYN))
699 {
700 /* Change the hash table entry to undefined, and let
701 _bfd_generic_link_add_one_symbol do the right thing
702 with the new definition. */
703 h->root.type = bfd_link_hash_undefined;
704 h->root.u.undef.abfd = h->root.u.def.section->owner;
705 }
706 }
707
708 if (! (_bfd_generic_link_add_one_symbol
709 (info, abfd, name, flags, sec, value, (const char *) NULL,
710 false, collect, (struct bfd_link_hash_entry **) sym_hash)))
711 goto error_return;
712
713 h = *sym_hash;
714 while (h->root.type == bfd_link_hash_indirect
715 || h->root.type == bfd_link_hash_warning)
716 h = (struct elf_link_hash_entry *) h->root.u.i.link;
717 *sym_hash = h;
718
719 new_weakdef = false;
720 if (dynamic
721 && definition
722 && (flags & BSF_WEAK) != 0
723 && ELF_ST_TYPE (sym.st_info) != STT_FUNC
724 && info->hash->creator->flavour == bfd_target_elf_flavour
725 && h->weakdef == NULL)
726 {
727 /* Keep a list of all weak defined non function symbols from
728 a dynamic object, using the weakdef field. Later in this
729 function we will set the weakdef field to the correct
730 value. We only put non-function symbols from dynamic
731 objects on this list, because that happens to be the only
732 time we need to know the normal symbol corresponding to a
733 weak symbol, and the information is time consuming to
734 figure out. If the weakdef field is not already NULL,
735 then this symbol was already defined by some previous
736 dynamic object, and we will be using that previous
737 definition anyhow. */
738
739 h->weakdef = weaks;
740 weaks = h;
741 new_weakdef = true;
742 }
743
744 /* Get the alignment of a common symbol. */
745 if (sym.st_shndx == SHN_COMMON
746 && h->root.type == bfd_link_hash_common)
747 h->root.u.c.p->alignment_power = bfd_log2 (sym.st_value);
748
749 if (info->hash->creator->flavour == bfd_target_elf_flavour)
750 {
751 int old_flags;
752 boolean dynsym;
753 int new_flag;
754
755 /* Remember the symbol size and type. */
756 if (sym.st_size != 0
757 && (definition || h->size == 0))
758 {
759 if (h->size != 0 && h->size != sym.st_size && ! wasweak)
760 (*_bfd_error_handler)
761 ("Warning: size of symbol `%s' changed from %lu to %lu in %s",
762 name, (unsigned long) h->size, (unsigned long) sym.st_size,
763 bfd_get_filename (abfd));
764
765 h->size = sym.st_size;
766 }
767 if (ELF_ST_TYPE (sym.st_info) != STT_NOTYPE
768 && (definition || h->type == STT_NOTYPE))
769 {
770 if (h->type != STT_NOTYPE
771 && h->type != ELF_ST_TYPE (sym.st_info)
772 && ! wasweak)
773 (*_bfd_error_handler)
774 ("Warning: type of symbol `%s' changed from %d to %d in %s",
775 name, h->type, ELF_ST_TYPE (sym.st_info),
776 bfd_get_filename (abfd));
777
778 h->type = ELF_ST_TYPE (sym.st_info);
779 }
780
781 /* Set a flag in the hash table entry indicating the type of
782 reference or definition we just found. Keep a count of
783 the number of dynamic symbols we find. A dynamic symbol
784 is one which is referenced or defined by both a regular
785 object and a shared object, or one which is referenced or
786 defined by more than one shared object. */
787 old_flags = h->elf_link_hash_flags;
788 dynsym = false;
789 if (! dynamic)
790 {
791 if (! definition)
792 new_flag = ELF_LINK_HASH_REF_REGULAR;
793 else
794 new_flag = ELF_LINK_HASH_DEF_REGULAR;
795 if (info->shared
796 || (old_flags & (ELF_LINK_HASH_DEF_DYNAMIC
797 | ELF_LINK_HASH_REF_DYNAMIC)) != 0)
798 dynsym = true;
799 }
800 else
801 {
802 if (! definition)
803 new_flag = ELF_LINK_HASH_REF_DYNAMIC;
804 else
805 new_flag = ELF_LINK_HASH_DEF_DYNAMIC;
806 if ((old_flags & new_flag) != 0
807 || (old_flags & (ELF_LINK_HASH_DEF_REGULAR
808 | ELF_LINK_HASH_REF_REGULAR)) != 0
809 || (h->weakdef != NULL
810 && (old_flags & (ELF_LINK_HASH_DEF_DYNAMIC
811 | ELF_LINK_HASH_REF_DYNAMIC)) != 0))
812 dynsym = true;
813 }
814
815 h->elf_link_hash_flags |= new_flag;
816 if (dynsym && h->dynindx == -1)
817 {
818 if (! _bfd_elf_link_record_dynamic_symbol (info, h))
819 goto error_return;
820 if (h->weakdef != NULL
821 && ! new_weakdef
822 && h->weakdef->dynindx == -1)
823 {
824 if (! _bfd_elf_link_record_dynamic_symbol (info,
825 h->weakdef))
826 goto error_return;
827 }
828 }
829 }
830 }
831
832 /* Now set the weakdefs field correctly for all the weak defined
833 symbols we found. The only way to do this is to search all the
834 symbols. Since we only need the information for non functions in
835 dynamic objects, that's the only time we actually put anything on
836 the list WEAKS. We need this information so that if a regular
837 object refers to a symbol defined weakly in a dynamic object, the
838 real symbol in the dynamic object is also put in the dynamic
839 symbols; we also must arrange for both symbols to point to the
840 same memory location. We could handle the general case of symbol
841 aliasing, but a general symbol alias can only be generated in
842 assembler code, handling it correctly would be very time
843 consuming, and other ELF linkers don't handle general aliasing
844 either. */
845 while (weaks != NULL)
846 {
847 struct elf_link_hash_entry *hlook;
848 asection *slook;
849 bfd_vma vlook;
850 struct elf_link_hash_entry **hpp;
851 struct elf_link_hash_entry **hppend;
852
853 hlook = weaks;
854 weaks = hlook->weakdef;
855 hlook->weakdef = NULL;
856
857 BFD_ASSERT (hlook->root.type == bfd_link_hash_defined
858 || hlook->root.type == bfd_link_hash_defweak
859 || hlook->root.type == bfd_link_hash_common
860 || hlook->root.type == bfd_link_hash_indirect);
861 slook = hlook->root.u.def.section;
862 vlook = hlook->root.u.def.value;
863
864 hpp = elf_sym_hashes (abfd);
865 hppend = hpp + extsymcount;
866 for (; hpp < hppend; hpp++)
867 {
868 struct elf_link_hash_entry *h;
869
870 h = *hpp;
871 if (h != NULL && h != hlook
872 && (h->root.type == bfd_link_hash_defined
873 || h->root.type == bfd_link_hash_defweak)
874 && h->root.u.def.section == slook
875 && h->root.u.def.value == vlook)
876 {
877 hlook->weakdef = h;
878
879 /* If the weak definition is in the list of dynamic
880 symbols, make sure the real definition is put there
881 as well. */
882 if (hlook->dynindx != -1
883 && h->dynindx == -1)
884 {
885 if (! _bfd_elf_link_record_dynamic_symbol (info, h))
886 goto error_return;
887 }
888
889 break;
890 }
891 }
892 }
893
894 if (buf != NULL)
895 {
896 free (buf);
897 buf = NULL;
898 }
899
900 /* If this object is the same format as the output object, and it is
901 not a shared library, then let the backend look through the
902 relocs.
903
904 This is required to build global offset table entries and to
905 arrange for dynamic relocs. It is not required for the
906 particular common case of linking non PIC code, even when linking
907 against shared libraries, but unfortunately there is no way of
908 knowing whether an object file has been compiled PIC or not.
909 Looking through the relocs is not particularly time consuming.
910 The problem is that we must either (1) keep the relocs in memory,
911 which causes the linker to require additional runtime memory or
912 (2) read the relocs twice from the input file, which wastes time.
913 This would be a good case for using mmap.
914
915 I have no idea how to handle linking PIC code into a file of a
916 different format. It probably can't be done. */
917 check_relocs = get_elf_backend_data (abfd)->check_relocs;
918 if (! dynamic
919 && abfd->xvec == info->hash->creator
920 && check_relocs != NULL)
921 {
922 asection *o;
923
924 for (o = abfd->sections; o != NULL; o = o->next)
925 {
926 Elf_Internal_Rela *internal_relocs;
927 boolean ok;
928
929 if ((o->flags & SEC_RELOC) == 0
930 || o->reloc_count == 0)
931 continue;
932
933 /* I believe we can ignore the relocs for any section which
934 does not form part of the final process image, such as a
935 debugging section. */
936 if ((o->flags & SEC_ALLOC) == 0)
937 continue;
938
939 internal_relocs = elf_link_read_relocs (abfd, o, (PTR) NULL,
940 (Elf_Internal_Rela *) NULL,
941 info->keep_memory);
942 if (internal_relocs == NULL)
943 goto error_return;
944
945 ok = (*check_relocs) (abfd, info, o, internal_relocs);
946
947 if (! info->keep_memory)
948 free (internal_relocs);
949
950 if (! ok)
951 goto error_return;
952 }
953 }
954
955 return true;
956
957 error_return:
958 if (buf != NULL)
959 free (buf);
960 if (dynbuf != NULL)
961 free (dynbuf);
962 return false;
963 }
964
965 /* Create some sections which will be filled in with dynamic linking
966 information. ABFD is an input file which requires dynamic sections
967 to be created. The dynamic sections take up virtual memory space
968 when the final executable is run, so we need to create them before
969 addresses are assigned to the output sections. We work out the
970 actual contents and size of these sections later. */
971
972 boolean
973 elf_link_create_dynamic_sections (abfd, info)
974 bfd *abfd;
975 struct bfd_link_info *info;
976 {
977 flagword flags;
978 register asection *s;
979 struct elf_link_hash_entry *h;
980 struct elf_backend_data *bed;
981
982 if (elf_hash_table (info)->dynamic_sections_created)
983 return true;
984
985 /* Make sure that all dynamic sections use the same input BFD. */
986 if (elf_hash_table (info)->dynobj == NULL)
987 elf_hash_table (info)->dynobj = abfd;
988 else
989 abfd = elf_hash_table (info)->dynobj;
990
991 /* Note that we set the SEC_IN_MEMORY flag for all of these
992 sections. */
993 flags = SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS | SEC_IN_MEMORY;
994
995 /* A dynamically linked executable has a .interp section, but a
996 shared library does not. */
997 if (! info->shared)
998 {
999 s = bfd_make_section (abfd, ".interp");
1000 if (s == NULL
1001 || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY))
1002 return false;
1003 }
1004
1005 s = bfd_make_section (abfd, ".dynsym");
1006 if (s == NULL
1007 || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
1008 || ! bfd_set_section_alignment (abfd, s, LOG_FILE_ALIGN))
1009 return false;
1010
1011 s = bfd_make_section (abfd, ".dynstr");
1012 if (s == NULL
1013 || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY))
1014 return false;
1015
1016 /* Create a strtab to hold the dynamic symbol names. */
1017 if (elf_hash_table (info)->dynstr == NULL)
1018 {
1019 elf_hash_table (info)->dynstr = elf_stringtab_init ();
1020 if (elf_hash_table (info)->dynstr == NULL)
1021 return false;
1022 }
1023
1024 s = bfd_make_section (abfd, ".dynamic");
1025 if (s == NULL
1026 || ! bfd_set_section_flags (abfd, s, flags)
1027 || ! bfd_set_section_alignment (abfd, s, LOG_FILE_ALIGN))
1028 return false;
1029
1030 /* The special symbol _DYNAMIC is always set to the start of the
1031 .dynamic section. This call occurs before we have processed the
1032 symbols for any dynamic object, so we don't have to worry about
1033 overriding a dynamic definition. We could set _DYNAMIC in a
1034 linker script, but we only want to define it if we are, in fact,
1035 creating a .dynamic section. We don't want to define it if there
1036 is no .dynamic section, since on some ELF platforms the start up
1037 code examines it to decide how to initialize the process. */
1038 h = NULL;
1039 if (! (_bfd_generic_link_add_one_symbol
1040 (info, abfd, "_DYNAMIC", BSF_GLOBAL, s, (bfd_vma) 0,
1041 (const char *) NULL, false, get_elf_backend_data (abfd)->collect,
1042 (struct bfd_link_hash_entry **) &h)))
1043 return false;
1044 h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
1045 h->type = STT_OBJECT;
1046
1047 if (info->shared
1048 && ! _bfd_elf_link_record_dynamic_symbol (info, h))
1049 return false;
1050
1051 s = bfd_make_section (abfd, ".hash");
1052 if (s == NULL
1053 || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY)
1054 || ! bfd_set_section_alignment (abfd, s, LOG_FILE_ALIGN))
1055 return false;
1056
1057 /* Let the backend create the rest of the sections. This lets the
1058 backend set the right flags. The backend will normally create
1059 the .got and .plt sections. */
1060 bed = get_elf_backend_data (abfd);
1061 if (! (*bed->elf_backend_create_dynamic_sections) (abfd, info))
1062 return false;
1063
1064 elf_hash_table (info)->dynamic_sections_created = true;
1065
1066 return true;
1067 }
1068
1069 /* Add an entry to the .dynamic table. */
1070
1071 boolean
1072 elf_add_dynamic_entry (info, tag, val)
1073 struct bfd_link_info *info;
1074 bfd_vma tag;
1075 bfd_vma val;
1076 {
1077 Elf_Internal_Dyn dyn;
1078 bfd *dynobj;
1079 asection *s;
1080 size_t newsize;
1081 bfd_byte *newcontents;
1082
1083 dynobj = elf_hash_table (info)->dynobj;
1084
1085 s = bfd_get_section_by_name (dynobj, ".dynamic");
1086 BFD_ASSERT (s != NULL);
1087
1088 newsize = s->_raw_size + sizeof (Elf_External_Dyn);
1089 if (s->contents == NULL)
1090 newcontents = (bfd_byte *) malloc (newsize);
1091 else
1092 newcontents = (bfd_byte *) realloc (s->contents, newsize);
1093 if (newcontents == NULL)
1094 {
1095 bfd_set_error (bfd_error_no_memory);
1096 return false;
1097 }
1098
1099 dyn.d_tag = tag;
1100 dyn.d_un.d_val = val;
1101 elf_swap_dyn_out (dynobj, &dyn,
1102 (Elf_External_Dyn *) (newcontents + s->_raw_size));
1103
1104 s->_raw_size = newsize;
1105 s->contents = newcontents;
1106
1107 return true;
1108 }
1109
1110 /* Read and swap the relocs for a section. They may have been cached.
1111 If the EXTERNAL_RELOCS and INTERNAL_RELOCS arguments are not NULL,
1112 they are used as buffers to read into. They are known to be large
1113 enough. If the INTERNAL_RELOCS relocs argument is NULL, the return
1114 value is allocated using either malloc or bfd_alloc, according to
1115 the KEEP_MEMORY argument. */
1116
1117 static Elf_Internal_Rela *
1118 elf_link_read_relocs (abfd, o, external_relocs, internal_relocs, keep_memory)
1119 bfd *abfd;
1120 asection *o;
1121 PTR external_relocs;
1122 Elf_Internal_Rela *internal_relocs;
1123 boolean keep_memory;
1124 {
1125 Elf_Internal_Shdr *rel_hdr;
1126 PTR alloc1 = NULL;
1127 Elf_Internal_Rela *alloc2 = NULL;
1128
1129 if (elf_section_data (o)->relocs != NULL)
1130 return elf_section_data (o)->relocs;
1131
1132 if (o->reloc_count == 0)
1133 return NULL;
1134
1135 rel_hdr = &elf_section_data (o)->rel_hdr;
1136
1137 if (internal_relocs == NULL)
1138 {
1139 size_t size;
1140
1141 size = o->reloc_count * sizeof (Elf_Internal_Rela);
1142 if (keep_memory)
1143 internal_relocs = (Elf_Internal_Rela *) bfd_alloc (abfd, size);
1144 else
1145 internal_relocs = alloc2 = (Elf_Internal_Rela *) malloc (size);
1146 if (internal_relocs == NULL)
1147 {
1148 bfd_set_error (bfd_error_no_memory);
1149 goto error_return;
1150 }
1151 }
1152
1153 if (external_relocs == NULL)
1154 {
1155 alloc1 = (PTR) malloc ((size_t) rel_hdr->sh_size);
1156 if (alloc1 == NULL)
1157 {
1158 bfd_set_error (bfd_error_no_memory);
1159 goto error_return;
1160 }
1161 external_relocs = alloc1;
1162 }
1163
1164 if ((bfd_seek (abfd, rel_hdr->sh_offset, SEEK_SET) != 0)
1165 || (bfd_read (external_relocs, 1, rel_hdr->sh_size, abfd)
1166 != rel_hdr->sh_size))
1167 goto error_return;
1168
1169 /* Swap in the relocs. For convenience, we always produce an
1170 Elf_Internal_Rela array; if the relocs are Rel, we set the addend
1171 to 0. */
1172 if (rel_hdr->sh_entsize == sizeof (Elf_External_Rel))
1173 {
1174 Elf_External_Rel *erel;
1175 Elf_External_Rel *erelend;
1176 Elf_Internal_Rela *irela;
1177
1178 erel = (Elf_External_Rel *) external_relocs;
1179 erelend = erel + o->reloc_count;
1180 irela = internal_relocs;
1181 for (; erel < erelend; erel++, irela++)
1182 {
1183 Elf_Internal_Rel irel;
1184
1185 elf_swap_reloc_in (abfd, erel, &irel);
1186 irela->r_offset = irel.r_offset;
1187 irela->r_info = irel.r_info;
1188 irela->r_addend = 0;
1189 }
1190 }
1191 else
1192 {
1193 Elf_External_Rela *erela;
1194 Elf_External_Rela *erelaend;
1195 Elf_Internal_Rela *irela;
1196
1197 BFD_ASSERT (rel_hdr->sh_entsize == sizeof (Elf_External_Rela));
1198
1199 erela = (Elf_External_Rela *) external_relocs;
1200 erelaend = erela + o->reloc_count;
1201 irela = internal_relocs;
1202 for (; erela < erelaend; erela++, irela++)
1203 elf_swap_reloca_in (abfd, erela, irela);
1204 }
1205
1206 /* Cache the results for next time, if we can. */
1207 if (keep_memory)
1208 elf_section_data (o)->relocs = internal_relocs;
1209
1210 if (alloc1 != NULL)
1211 free (alloc1);
1212
1213 /* Don't free alloc2, since if it was allocated we are passing it
1214 back (under the name of internal_relocs). */
1215
1216 return internal_relocs;
1217
1218 error_return:
1219 if (alloc1 != NULL)
1220 free (alloc1);
1221 if (alloc2 != NULL)
1222 free (alloc2);
1223 return NULL;
1224 }
1225
1226 /* Record an assignment to a symbol made by a linker script. We need
1227 this in case some dynamic object refers to this symbol. */
1228
1229 /*ARGSUSED*/
1230 boolean
1231 NAME(bfd_elf,record_link_assignment) (output_bfd, info, name, provide)
1232 bfd *output_bfd;
1233 struct bfd_link_info *info;
1234 const char *name;
1235 boolean provide;
1236 {
1237 struct elf_link_hash_entry *h;
1238
1239 if (info->hash->creator->flavour != bfd_target_elf_flavour)
1240 return true;
1241
1242 h = elf_link_hash_lookup (elf_hash_table (info), name, true, true, false);
1243 if (h == NULL)
1244 return false;
1245
1246 /* If this symbol is being provided by the linker script, and it is
1247 currently defined by a dynamic object, but not by a regular
1248 object, then mark it as undefined so that the generic linker will
1249 force the correct value. */
1250 if (provide
1251 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0
1252 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
1253 h->root.type = bfd_link_hash_undefined;
1254
1255 h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR;
1256 h->type = STT_OBJECT;
1257
1258 if (((h->elf_link_hash_flags & (ELF_LINK_HASH_DEF_DYNAMIC
1259 | ELF_LINK_HASH_REF_DYNAMIC)) != 0
1260 || info->shared)
1261 && h->dynindx == -1)
1262 {
1263 if (! _bfd_elf_link_record_dynamic_symbol (info, h))
1264 return false;
1265
1266 /* If this is a weak defined symbol, and we know a corresponding
1267 real symbol from the same dynamic object, make sure the real
1268 symbol is also made into a dynamic symbol. */
1269 if (h->weakdef != NULL
1270 && h->weakdef->dynindx == -1)
1271 {
1272 if (! _bfd_elf_link_record_dynamic_symbol (info, h->weakdef))
1273 return false;
1274 }
1275 }
1276
1277 return true;
1278 }
1279
1280 /* Array used to determine the number of hash table buckets to use
1281 based on the number of symbols there are. If there are fewer than
1282 3 symbols we use 1 bucket, fewer than 17 symbols we use 3 buckets,
1283 fewer than 37 we use 17 buckets, and so forth. We never use more
1284 than 521 buckets. */
1285
1286 static const size_t elf_buckets[] =
1287 {
1288 1, 3, 17, 37, 67, 97, 131, 197, 263, 521, 0
1289 };
1290
1291 /* Set up the sizes and contents of the ELF dynamic sections. This is
1292 called by the ELF linker emulation before_allocation routine. We
1293 must set the sizes of the sections before the linker sets the
1294 addresses of the various sections. */
1295
1296 boolean
1297 NAME(bfd_elf,size_dynamic_sections) (output_bfd, soname, rpath,
1298 export_dynamic, info, sinterpptr)
1299 bfd *output_bfd;
1300 const char *soname;
1301 const char *rpath;
1302 boolean export_dynamic;
1303 struct bfd_link_info *info;
1304 asection **sinterpptr;
1305 {
1306 bfd *dynobj;
1307 struct elf_backend_data *bed;
1308
1309 *sinterpptr = NULL;
1310
1311 if (info->hash->creator->flavour != bfd_target_elf_flavour)
1312 return true;
1313
1314 dynobj = elf_hash_table (info)->dynobj;
1315
1316 /* If there were no dynamic objects in the link, there is nothing to
1317 do here. */
1318 if (dynobj == NULL)
1319 return true;
1320
1321 /* If we are supposed to export all symbols into the dynamic symbol
1322 table (this is not the normal case), then do so. */
1323 if (export_dynamic)
1324 {
1325 struct elf_info_failed eif;
1326
1327 eif.failed = false;
1328 eif.info = info;
1329 elf_link_hash_traverse (elf_hash_table (info), elf_export_symbol,
1330 (PTR) &eif);
1331 if (eif.failed)
1332 return false;
1333 }
1334
1335 if (elf_hash_table (info)->dynamic_sections_created)
1336 {
1337 struct elf_info_failed eif;
1338 bfd_size_type strsize;
1339
1340 *sinterpptr = bfd_get_section_by_name (dynobj, ".interp");
1341 BFD_ASSERT (*sinterpptr != NULL || info->shared);
1342
1343 if (soname != NULL)
1344 {
1345 bfd_size_type indx;
1346
1347 indx = _bfd_stringtab_add (elf_hash_table (info)->dynstr, soname,
1348 true, true);
1349 if (indx == (bfd_size_type) -1
1350 || ! elf_add_dynamic_entry (info, DT_SONAME, indx))
1351 return false;
1352 }
1353
1354 if (info->symbolic)
1355 {
1356 if (! elf_add_dynamic_entry (info, DT_SYMBOLIC, 0))
1357 return false;
1358 }
1359
1360 if (rpath != NULL)
1361 {
1362 bfd_size_type indx;
1363
1364 indx = _bfd_stringtab_add (elf_hash_table (info)->dynstr, rpath,
1365 true, true);
1366 if (indx == (bfd_size_type) -1
1367 || ! elf_add_dynamic_entry (info, DT_RPATH, indx))
1368 return false;
1369 }
1370
1371 /* Find all symbols which were defined in a dynamic object and make
1372 the backend pick a reasonable value for them. */
1373 eif.failed = false;
1374 eif.info = info;
1375 elf_link_hash_traverse (elf_hash_table (info),
1376 elf_adjust_dynamic_symbol,
1377 (PTR) &eif);
1378 if (eif.failed)
1379 return false;
1380
1381 /* Add some entries to the .dynamic section. We fill in some of the
1382 values later, in elf_bfd_final_link, but we must add the entries
1383 now so that we know the final size of the .dynamic section. */
1384 if (elf_link_hash_lookup (elf_hash_table (info), "_init", false,
1385 false, false) != NULL)
1386 {
1387 if (! elf_add_dynamic_entry (info, DT_INIT, 0))
1388 return false;
1389 }
1390 if (elf_link_hash_lookup (elf_hash_table (info), "_fini", false,
1391 false, false) != NULL)
1392 {
1393 if (! elf_add_dynamic_entry (info, DT_FINI, 0))
1394 return false;
1395 }
1396 strsize = _bfd_stringtab_size (elf_hash_table (info)->dynstr);
1397 if (! elf_add_dynamic_entry (info, DT_HASH, 0)
1398 || ! elf_add_dynamic_entry (info, DT_STRTAB, 0)
1399 || ! elf_add_dynamic_entry (info, DT_SYMTAB, 0)
1400 || ! elf_add_dynamic_entry (info, DT_STRSZ, strsize)
1401 || ! elf_add_dynamic_entry (info, DT_SYMENT,
1402 sizeof (Elf_External_Sym)))
1403 return false;
1404 }
1405
1406 /* The backend must work out the sizes of all the other dynamic
1407 sections. */
1408 bed = get_elf_backend_data (output_bfd);
1409 if (! (*bed->elf_backend_size_dynamic_sections) (output_bfd, info))
1410 return false;
1411
1412 if (elf_hash_table (info)->dynamic_sections_created)
1413 {
1414 size_t dynsymcount;
1415 asection *s;
1416 size_t i;
1417 size_t bucketcount = 0;
1418 Elf_Internal_Sym isym;
1419
1420 /* Set the size of the .dynsym and .hash sections. We counted
1421 the number of dynamic symbols in elf_link_add_object_symbols.
1422 We will build the contents of .dynsym and .hash when we build
1423 the final symbol table, because until then we do not know the
1424 correct value to give the symbols. We built the .dynstr
1425 section as we went along in elf_link_add_object_symbols. */
1426 dynsymcount = elf_hash_table (info)->dynsymcount;
1427 s = bfd_get_section_by_name (dynobj, ".dynsym");
1428 BFD_ASSERT (s != NULL);
1429 s->_raw_size = dynsymcount * sizeof (Elf_External_Sym);
1430 s->contents = (bfd_byte *) bfd_alloc (output_bfd, s->_raw_size);
1431 if (s->contents == NULL && s->_raw_size != 0)
1432 {
1433 bfd_set_error (bfd_error_no_memory);
1434 return false;
1435 }
1436
1437 /* The first entry in .dynsym is a dummy symbol. */
1438 isym.st_value = 0;
1439 isym.st_size = 0;
1440 isym.st_name = 0;
1441 isym.st_info = 0;
1442 isym.st_other = 0;
1443 isym.st_shndx = 0;
1444 elf_swap_symbol_out (output_bfd, &isym,
1445 (PTR) (Elf_External_Sym *) s->contents);
1446
1447 for (i = 0; elf_buckets[i] != 0; i++)
1448 {
1449 bucketcount = elf_buckets[i];
1450 if (dynsymcount < elf_buckets[i + 1])
1451 break;
1452 }
1453
1454 s = bfd_get_section_by_name (dynobj, ".hash");
1455 BFD_ASSERT (s != NULL);
1456 s->_raw_size = (2 + bucketcount + dynsymcount) * (ARCH_SIZE / 8);
1457 s->contents = (bfd_byte *) bfd_alloc (output_bfd, s->_raw_size);
1458 if (s->contents == NULL)
1459 {
1460 bfd_set_error (bfd_error_no_memory);
1461 return false;
1462 }
1463 memset (s->contents, 0, (size_t) s->_raw_size);
1464
1465 put_word (output_bfd, bucketcount, s->contents);
1466 put_word (output_bfd, dynsymcount, s->contents + (ARCH_SIZE / 8));
1467
1468 elf_hash_table (info)->bucketcount = bucketcount;
1469
1470 s = bfd_get_section_by_name (dynobj, ".dynstr");
1471 BFD_ASSERT (s != NULL);
1472 s->_raw_size = _bfd_stringtab_size (elf_hash_table (info)->dynstr);
1473
1474 if (! elf_add_dynamic_entry (info, DT_NULL, 0))
1475 return false;
1476 }
1477
1478 return true;
1479 }
1480
1481 /* This routine is used to export all defined symbols into the dynamic
1482 symbol table. It is called via elf_link_hash_traverse. */
1483
1484 static boolean
1485 elf_export_symbol (h, data)
1486 struct elf_link_hash_entry *h;
1487 PTR data;
1488 {
1489 struct elf_info_failed *eif = (struct elf_info_failed *) data;
1490
1491 if (h->dynindx == -1
1492 && (h->elf_link_hash_flags
1493 & (ELF_LINK_HASH_DEF_REGULAR | ELF_LINK_HASH_REF_REGULAR)) != 0)
1494 {
1495 if (! _bfd_elf_link_record_dynamic_symbol (eif->info, h))
1496 {
1497 eif->failed = true;
1498 return false;
1499 }
1500 }
1501
1502 return true;
1503 }
1504
1505 /* Make the backend pick a good value for a dynamic symbol. This is
1506 called via elf_link_hash_traverse, and also calls itself
1507 recursively. */
1508
1509 static boolean
1510 elf_adjust_dynamic_symbol (h, data)
1511 struct elf_link_hash_entry *h;
1512 PTR data;
1513 {
1514 struct elf_info_failed *eif = (struct elf_info_failed *) data;
1515 bfd *dynobj;
1516 struct elf_backend_data *bed;
1517
1518 /* If -Bsymbolic was used (which means to bind references to global
1519 symbols to the definition within the shared object), and this
1520 symbol was defined in a regular object, then it actually doesn't
1521 need a PLT entry. */
1522 if ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) != 0
1523 && eif->info->shared
1524 && eif->info->symbolic
1525 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0)
1526 h->elf_link_hash_flags &=~ ELF_LINK_HASH_NEEDS_PLT;
1527
1528 /* If this symbol does not require a PLT entry, and it is not
1529 defined by a dynamic object, or is not referenced by a regular
1530 object, ignore it. We do have to handle a weak defined symbol,
1531 even if no regular object refers to it, if we decided to add it
1532 to the dynamic symbol table. FIXME: Do we normally need to worry
1533 about symbols which are defined by one dynamic object and
1534 referenced by another one? */
1535 if ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) == 0
1536 && ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0
1537 || (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) == 0
1538 || ((h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) == 0
1539 && (h->weakdef == NULL || h->weakdef->dynindx == -1))))
1540 return true;
1541
1542 /* If we've already adjusted this symbol, don't do it again. This
1543 can happen via a recursive call. */
1544 if ((h->elf_link_hash_flags & ELF_LINK_HASH_DYNAMIC_ADJUSTED) != 0)
1545 return true;
1546
1547 /* Don't look at this symbol again. Note that we must set this
1548 after checking the above conditions, because we may look at a
1549 symbol once, decide not to do anything, and then get called
1550 recursively later after REF_REGULAR is set below. */
1551 h->elf_link_hash_flags |= ELF_LINK_HASH_DYNAMIC_ADJUSTED;
1552
1553 /* If this is a weak definition, and we know a real definition, and
1554 the real symbol is not itself defined by a regular object file,
1555 then get a good value for the real definition. We handle the
1556 real symbol first, for the convenience of the backend routine.
1557
1558 Note that there is a confusing case here. If the real definition
1559 is defined by a regular object file, we don't get the real symbol
1560 from the dynamic object, but we do get the weak symbol. If the
1561 processor backend uses a COPY reloc, then if some routine in the
1562 dynamic object changes the real symbol, we will not see that
1563 change in the corresponding weak symbol. This is the way other
1564 ELF linkers work as well, and seems to be a result of the shared
1565 library model.
1566
1567 I will clarify this issue. Most SVR4 shared libraries define the
1568 variable _timezone and define timezone as a weak synonym. The
1569 tzset call changes _timezone. If you write
1570 extern int timezone;
1571 int _timezone = 5;
1572 int main () { tzset (); printf ("%d %d\n", timezone, _timezone); }
1573 you might expect that, since timezone is a synonym for _timezone,
1574 the same number will print both times. However, if the processor
1575 backend uses a COPY reloc, then actually timezone will be copied
1576 into your process image, and, since you define _timezone
1577 yourself, _timezone will not. Thus timezone and _timezone will
1578 wind up at different memory locations. The tzset call will set
1579 _timezone, leaving timezone unchanged. */
1580
1581 if (h->weakdef != NULL)
1582 {
1583 struct elf_link_hash_entry *weakdef;
1584
1585 BFD_ASSERT (h->root.type == bfd_link_hash_defined
1586 || h->root.type == bfd_link_hash_defweak);
1587 weakdef = h->weakdef;
1588 BFD_ASSERT (weakdef->root.type == bfd_link_hash_defined
1589 || weakdef->root.type == bfd_link_hash_defweak);
1590 BFD_ASSERT (weakdef->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC);
1591 if ((weakdef->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0)
1592 {
1593 /* This symbol is defined by a regular object file, so we
1594 will not do anything special. Clear weakdef for the
1595 convenience of the processor backend. */
1596 h->weakdef = NULL;
1597 }
1598 else
1599 {
1600 /* There is an implicit reference by a regular object file
1601 via the weak symbol. */
1602 weakdef->elf_link_hash_flags |= ELF_LINK_HASH_REF_REGULAR;
1603 if (! elf_adjust_dynamic_symbol (weakdef, (PTR) eif))
1604 return false;
1605 }
1606 }
1607
1608 dynobj = elf_hash_table (eif->info)->dynobj;
1609 bed = get_elf_backend_data (dynobj);
1610 if (! (*bed->elf_backend_adjust_dynamic_symbol) (eif->info, h))
1611 {
1612 eif->failed = true;
1613 return false;
1614 }
1615
1616 return true;
1617 }
1618 \f
1619 /* Final phase of ELF linker. */
1620
1621 /* A structure we use to avoid passing large numbers of arguments. */
1622
1623 struct elf_final_link_info
1624 {
1625 /* General link information. */
1626 struct bfd_link_info *info;
1627 /* Output BFD. */
1628 bfd *output_bfd;
1629 /* Symbol string table. */
1630 struct bfd_strtab_hash *symstrtab;
1631 /* .dynsym section. */
1632 asection *dynsym_sec;
1633 /* .hash section. */
1634 asection *hash_sec;
1635 /* Buffer large enough to hold contents of any section. */
1636 bfd_byte *contents;
1637 /* Buffer large enough to hold external relocs of any section. */
1638 PTR external_relocs;
1639 /* Buffer large enough to hold internal relocs of any section. */
1640 Elf_Internal_Rela *internal_relocs;
1641 /* Buffer large enough to hold external local symbols of any input
1642 BFD. */
1643 Elf_External_Sym *external_syms;
1644 /* Buffer large enough to hold internal local symbols of any input
1645 BFD. */
1646 Elf_Internal_Sym *internal_syms;
1647 /* Array large enough to hold a symbol index for each local symbol
1648 of any input BFD. */
1649 long *indices;
1650 /* Array large enough to hold a section pointer for each local
1651 symbol of any input BFD. */
1652 asection **sections;
1653 /* Buffer to hold swapped out symbols. */
1654 Elf_External_Sym *symbuf;
1655 /* Number of swapped out symbols in buffer. */
1656 size_t symbuf_count;
1657 /* Number of symbols which fit in symbuf. */
1658 size_t symbuf_size;
1659 };
1660
1661 static boolean elf_link_output_sym
1662 PARAMS ((struct elf_final_link_info *, const char *,
1663 Elf_Internal_Sym *, asection *));
1664 static boolean elf_link_flush_output_syms
1665 PARAMS ((struct elf_final_link_info *));
1666 static boolean elf_link_output_extsym
1667 PARAMS ((struct elf_link_hash_entry *, PTR));
1668 static boolean elf_link_input_bfd
1669 PARAMS ((struct elf_final_link_info *, bfd *));
1670 static boolean elf_reloc_link_order
1671 PARAMS ((bfd *, struct bfd_link_info *, asection *,
1672 struct bfd_link_order *));
1673
1674 /* This struct is used to pass information to routines called via
1675 elf_link_hash_traverse which must return failure. */
1676
1677 struct elf_finfo_failed
1678 {
1679 boolean failed;
1680 struct elf_final_link_info *finfo;
1681 };
1682
1683 /* Do the final step of an ELF link. */
1684
1685 boolean
1686 elf_bfd_final_link (abfd, info)
1687 bfd *abfd;
1688 struct bfd_link_info *info;
1689 {
1690 boolean dynamic;
1691 bfd *dynobj;
1692 struct elf_final_link_info finfo;
1693 register asection *o;
1694 register struct bfd_link_order *p;
1695 register bfd *sub;
1696 size_t max_contents_size;
1697 size_t max_external_reloc_size;
1698 size_t max_internal_reloc_count;
1699 size_t max_sym_count;
1700 file_ptr off;
1701 Elf_Internal_Sym elfsym;
1702 unsigned int i;
1703 Elf_Internal_Shdr *symtab_hdr;
1704 Elf_Internal_Shdr *symstrtab_hdr;
1705 struct elf_backend_data *bed = get_elf_backend_data (abfd);
1706 struct elf_finfo_failed eif;
1707
1708 if (info->shared)
1709 abfd->flags |= DYNAMIC;
1710
1711 dynamic = elf_hash_table (info)->dynamic_sections_created;
1712 dynobj = elf_hash_table (info)->dynobj;
1713
1714 finfo.info = info;
1715 finfo.output_bfd = abfd;
1716 finfo.symstrtab = elf_stringtab_init ();
1717 if (finfo.symstrtab == NULL)
1718 return false;
1719 if (! dynamic)
1720 {
1721 finfo.dynsym_sec = NULL;
1722 finfo.hash_sec = NULL;
1723 }
1724 else
1725 {
1726 finfo.dynsym_sec = bfd_get_section_by_name (dynobj, ".dynsym");
1727 finfo.hash_sec = bfd_get_section_by_name (dynobj, ".hash");
1728 BFD_ASSERT (finfo.dynsym_sec != NULL && finfo.hash_sec != NULL);
1729 }
1730 finfo.contents = NULL;
1731 finfo.external_relocs = NULL;
1732 finfo.internal_relocs = NULL;
1733 finfo.external_syms = NULL;
1734 finfo.internal_syms = NULL;
1735 finfo.indices = NULL;
1736 finfo.sections = NULL;
1737 finfo.symbuf = NULL;
1738 finfo.symbuf_count = 0;
1739
1740 /* Count up the number of relocations we will output for each output
1741 section, so that we know the sizes of the reloc sections. We
1742 also figure out some maximum sizes. */
1743 max_contents_size = 0;
1744 max_external_reloc_size = 0;
1745 max_internal_reloc_count = 0;
1746 max_sym_count = 0;
1747 for (o = abfd->sections; o != (asection *) NULL; o = o->next)
1748 {
1749 o->reloc_count = 0;
1750
1751 for (p = o->link_order_head; p != NULL; p = p->next)
1752 {
1753 if (p->type == bfd_section_reloc_link_order
1754 || p->type == bfd_symbol_reloc_link_order)
1755 ++o->reloc_count;
1756 else if (p->type == bfd_indirect_link_order)
1757 {
1758 asection *sec;
1759
1760 sec = p->u.indirect.section;
1761
1762 if (info->relocateable)
1763 o->reloc_count += sec->reloc_count;
1764
1765 if (sec->_raw_size > max_contents_size)
1766 max_contents_size = sec->_raw_size;
1767 if (sec->_cooked_size > max_contents_size)
1768 max_contents_size = sec->_cooked_size;
1769
1770 /* We are interested in just local symbols, not all
1771 symbols. */
1772 if (bfd_get_flavour (sec->owner) == bfd_target_elf_flavour)
1773 {
1774 size_t sym_count;
1775
1776 if (elf_bad_symtab (sec->owner))
1777 sym_count = (elf_tdata (sec->owner)->symtab_hdr.sh_size
1778 / sizeof (Elf_External_Sym));
1779 else
1780 sym_count = elf_tdata (sec->owner)->symtab_hdr.sh_info;
1781
1782 if (sym_count > max_sym_count)
1783 max_sym_count = sym_count;
1784
1785 if ((sec->flags & SEC_RELOC) != 0)
1786 {
1787 size_t ext_size;
1788
1789 ext_size = elf_section_data (sec)->rel_hdr.sh_size;
1790 if (ext_size > max_external_reloc_size)
1791 max_external_reloc_size = ext_size;
1792 if (sec->reloc_count > max_internal_reloc_count)
1793 max_internal_reloc_count = sec->reloc_count;
1794 }
1795 }
1796 }
1797 }
1798
1799 if (o->reloc_count > 0)
1800 o->flags |= SEC_RELOC;
1801 else
1802 {
1803 /* Explicitly clear the SEC_RELOC flag. The linker tends to
1804 set it (this is probably a bug) and if it is set
1805 assign_section_numbers will create a reloc section. */
1806 o->flags &=~ SEC_RELOC;
1807 }
1808
1809 /* If the SEC_ALLOC flag is not set, force the section VMA to
1810 zero. This is done in elf_fake_sections as well, but forcing
1811 the VMA to 0 here will ensure that relocs against these
1812 sections are handled correctly. */
1813 if ((o->flags & SEC_ALLOC) == 0)
1814 o->vma = 0;
1815 }
1816
1817 /* Figure out the file positions for everything but the symbol table
1818 and the relocs. We set symcount to force assign_section_numbers
1819 to create a symbol table. */
1820 abfd->symcount = info->strip == strip_all ? 0 : 1;
1821 BFD_ASSERT (! abfd->output_has_begun);
1822 if (! _bfd_elf_compute_section_file_positions (abfd, info))
1823 goto error_return;
1824
1825 /* That created the reloc sections. Set their sizes, and assign
1826 them file positions, and allocate some buffers. */
1827 for (o = abfd->sections; o != NULL; o = o->next)
1828 {
1829 if ((o->flags & SEC_RELOC) != 0)
1830 {
1831 Elf_Internal_Shdr *rel_hdr;
1832 register struct elf_link_hash_entry **p, **pend;
1833
1834 rel_hdr = &elf_section_data (o)->rel_hdr;
1835
1836 rel_hdr->sh_size = rel_hdr->sh_entsize * o->reloc_count;
1837
1838 /* The contents field must last into write_object_contents,
1839 so we allocate it with bfd_alloc rather than malloc. */
1840 rel_hdr->contents = (PTR) bfd_alloc (abfd, rel_hdr->sh_size);
1841 if (rel_hdr->contents == NULL && rel_hdr->sh_size != 0)
1842 {
1843 bfd_set_error (bfd_error_no_memory);
1844 goto error_return;
1845 }
1846
1847 p = ((struct elf_link_hash_entry **)
1848 malloc (o->reloc_count
1849 * sizeof (struct elf_link_hash_entry *)));
1850 if (p == NULL && o->reloc_count != 0)
1851 {
1852 bfd_set_error (bfd_error_no_memory);
1853 goto error_return;
1854 }
1855 elf_section_data (o)->rel_hashes = p;
1856 pend = p + o->reloc_count;
1857 for (; p < pend; p++)
1858 *p = NULL;
1859
1860 /* Use the reloc_count field as an index when outputting the
1861 relocs. */
1862 o->reloc_count = 0;
1863 }
1864 }
1865
1866 _bfd_elf_assign_file_positions_for_relocs (abfd);
1867
1868 /* We have now assigned file positions for all the sections except
1869 .symtab and .strtab. We start the .symtab section at the current
1870 file position, and write directly to it. We build the .strtab
1871 section in memory. When we add .dynsym support, we will build
1872 that in memory as well (.dynsym is smaller than .symtab). */
1873 abfd->symcount = 0;
1874 symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
1875 /* sh_name is set in prep_headers. */
1876 symtab_hdr->sh_type = SHT_SYMTAB;
1877 symtab_hdr->sh_flags = 0;
1878 symtab_hdr->sh_addr = 0;
1879 symtab_hdr->sh_size = 0;
1880 symtab_hdr->sh_entsize = sizeof (Elf_External_Sym);
1881 /* sh_link is set in assign_section_numbers. */
1882 /* sh_info is set below. */
1883 /* sh_offset is set just below. */
1884 symtab_hdr->sh_addralign = 4; /* FIXME: system dependent? */
1885
1886 off = elf_tdata (abfd)->next_file_pos;
1887 off = _bfd_elf_assign_file_position_for_section (symtab_hdr, off, true);
1888
1889 /* Note that at this point elf_tdata (abfd)->next_file_pos is
1890 incorrect. We do not yet know the size of the .symtab section.
1891 We correct next_file_pos below, after we do know the size. */
1892
1893 /* Allocate a buffer to hold swapped out symbols. This is to avoid
1894 continuously seeking to the right position in the file. */
1895 if (! info->keep_memory || max_sym_count < 20)
1896 finfo.symbuf_size = 20;
1897 else
1898 finfo.symbuf_size = max_sym_count;
1899 finfo.symbuf = ((Elf_External_Sym *)
1900 malloc (finfo.symbuf_size * sizeof (Elf_External_Sym)));
1901 if (finfo.symbuf == NULL)
1902 {
1903 bfd_set_error (bfd_error_no_memory);
1904 goto error_return;
1905 }
1906
1907 /* Start writing out the symbol table. The first symbol is always a
1908 dummy symbol. */
1909 elfsym.st_value = 0;
1910 elfsym.st_size = 0;
1911 elfsym.st_info = 0;
1912 elfsym.st_other = 0;
1913 elfsym.st_shndx = SHN_UNDEF;
1914 if (! elf_link_output_sym (&finfo, (const char *) NULL,
1915 &elfsym, bfd_und_section_ptr))
1916 goto error_return;
1917
1918 #if 0
1919 /* Some standard ELF linkers do this, but we don't because it causes
1920 bootstrap comparison failures. */
1921 /* Output a file symbol for the output file as the second symbol.
1922 We output this even if we are discarding local symbols, although
1923 I'm not sure if this is correct. */
1924 elfsym.st_value = 0;
1925 elfsym.st_size = 0;
1926 elfsym.st_info = ELF_ST_INFO (STB_LOCAL, STT_FILE);
1927 elfsym.st_other = 0;
1928 elfsym.st_shndx = SHN_ABS;
1929 if (! elf_link_output_sym (&finfo, bfd_get_filename (abfd),
1930 &elfsym, bfd_abs_section_ptr))
1931 goto error_return;
1932 #endif
1933
1934 /* Output a symbol for each section. We output these even if we are
1935 discarding local symbols, since they are used for relocs. These
1936 symbols have no names. We store the index of each one in the
1937 index field of the section, so that we can find it again when
1938 outputting relocs. */
1939 elfsym.st_value = 0;
1940 elfsym.st_size = 0;
1941 elfsym.st_info = ELF_ST_INFO (STB_LOCAL, STT_SECTION);
1942 elfsym.st_other = 0;
1943 for (i = 1; i < elf_elfheader (abfd)->e_shnum; i++)
1944 {
1945 o = section_from_elf_index (abfd, i);
1946 if (o != NULL)
1947 o->target_index = abfd->symcount;
1948 elfsym.st_shndx = i;
1949 if (! elf_link_output_sym (&finfo, (const char *) NULL,
1950 &elfsym, o))
1951 goto error_return;
1952 }
1953
1954 /* Allocate some memory to hold information read in from the input
1955 files. */
1956 finfo.contents = (bfd_byte *) malloc (max_contents_size);
1957 finfo.external_relocs = (PTR) malloc (max_external_reloc_size);
1958 finfo.internal_relocs = ((Elf_Internal_Rela *)
1959 malloc (max_internal_reloc_count
1960 * sizeof (Elf_Internal_Rela)));
1961 finfo.external_syms = ((Elf_External_Sym *)
1962 malloc (max_sym_count * sizeof (Elf_External_Sym)));
1963 finfo.internal_syms = ((Elf_Internal_Sym *)
1964 malloc (max_sym_count * sizeof (Elf_Internal_Sym)));
1965 finfo.indices = (long *) malloc (max_sym_count * sizeof (long));
1966 finfo.sections = (asection **) malloc (max_sym_count * sizeof (asection *));
1967 if ((finfo.contents == NULL && max_contents_size != 0)
1968 || (finfo.external_relocs == NULL && max_external_reloc_size != 0)
1969 || (finfo.internal_relocs == NULL && max_internal_reloc_count != 0)
1970 || (finfo.external_syms == NULL && max_sym_count != 0)
1971 || (finfo.internal_syms == NULL && max_sym_count != 0)
1972 || (finfo.indices == NULL && max_sym_count != 0)
1973 || (finfo.sections == NULL && max_sym_count != 0))
1974 {
1975 bfd_set_error (bfd_error_no_memory);
1976 goto error_return;
1977 }
1978
1979 /* Since ELF permits relocations to be against local symbols, we
1980 must have the local symbols available when we do the relocations.
1981 Since we would rather only read the local symbols once, and we
1982 would rather not keep them in memory, we handle all the
1983 relocations for a single input file at the same time.
1984
1985 Unfortunately, there is no way to know the total number of local
1986 symbols until we have seen all of them, and the local symbol
1987 indices precede the global symbol indices. This means that when
1988 we are generating relocateable output, and we see a reloc against
1989 a global symbol, we can not know the symbol index until we have
1990 finished examining all the local symbols to see which ones we are
1991 going to output. To deal with this, we keep the relocations in
1992 memory, and don't output them until the end of the link. This is
1993 an unfortunate waste of memory, but I don't see a good way around
1994 it. Fortunately, it only happens when performing a relocateable
1995 link, which is not the common case. FIXME: If keep_memory is set
1996 we could write the relocs out and then read them again; I don't
1997 know how bad the memory loss will be. */
1998
1999 for (sub = info->input_bfds; sub != NULL; sub = sub->next)
2000 sub->output_has_begun = false;
2001 for (o = abfd->sections; o != NULL; o = o->next)
2002 {
2003 for (p = o->link_order_head; p != NULL; p = p->next)
2004 {
2005 if (p->type == bfd_indirect_link_order
2006 && (bfd_get_flavour (p->u.indirect.section->owner)
2007 == bfd_target_elf_flavour))
2008 {
2009 sub = p->u.indirect.section->owner;
2010 if (! sub->output_has_begun)
2011 {
2012 if (! elf_link_input_bfd (&finfo, sub))
2013 goto error_return;
2014 sub->output_has_begun = true;
2015 }
2016 }
2017 else if (p->type == bfd_section_reloc_link_order
2018 || p->type == bfd_symbol_reloc_link_order)
2019 {
2020 if (! elf_reloc_link_order (abfd, info, o, p))
2021 goto error_return;
2022 }
2023 else
2024 {
2025 if (! _bfd_default_link_order (abfd, info, o, p))
2026 goto error_return;
2027 }
2028 }
2029 }
2030
2031 /* That wrote out all the local symbols. Finish up the symbol table
2032 with the global symbols. */
2033
2034 /* The sh_info field records the index of the first non local
2035 symbol. */
2036 symtab_hdr->sh_info = abfd->symcount;
2037 if (dynamic)
2038 elf_section_data (finfo.dynsym_sec->output_section)->this_hdr.sh_info = 1;
2039
2040 /* We get the global symbols from the hash table. */
2041 eif.failed = false;
2042 eif.finfo = &finfo;
2043 elf_link_hash_traverse (elf_hash_table (info), elf_link_output_extsym,
2044 (PTR) &eif);
2045 if (eif.failed)
2046 return false;
2047
2048 /* Flush all symbols to the file. */
2049 if (! elf_link_flush_output_syms (&finfo))
2050 return false;
2051
2052 /* Now we know the size of the symtab section. */
2053 off += symtab_hdr->sh_size;
2054
2055 /* Finish up and write out the symbol string table (.strtab)
2056 section. */
2057 symstrtab_hdr = &elf_tdata (abfd)->strtab_hdr;
2058 /* sh_name was set in prep_headers. */
2059 symstrtab_hdr->sh_type = SHT_STRTAB;
2060 symstrtab_hdr->sh_flags = 0;
2061 symstrtab_hdr->sh_addr = 0;
2062 symstrtab_hdr->sh_size = _bfd_stringtab_size (finfo.symstrtab);
2063 symstrtab_hdr->sh_entsize = 0;
2064 symstrtab_hdr->sh_link = 0;
2065 symstrtab_hdr->sh_info = 0;
2066 /* sh_offset is set just below. */
2067 symstrtab_hdr->sh_addralign = 1;
2068
2069 off = _bfd_elf_assign_file_position_for_section (symstrtab_hdr, off, true);
2070 elf_tdata (abfd)->next_file_pos = off;
2071
2072 if (bfd_seek (abfd, symstrtab_hdr->sh_offset, SEEK_SET) != 0
2073 || ! _bfd_stringtab_emit (abfd, finfo.symstrtab))
2074 return false;
2075
2076 /* Adjust the relocs to have the correct symbol indices. */
2077 for (o = abfd->sections; o != NULL; o = o->next)
2078 {
2079 struct elf_link_hash_entry **rel_hash;
2080 Elf_Internal_Shdr *rel_hdr;
2081
2082 if ((o->flags & SEC_RELOC) == 0)
2083 continue;
2084
2085 rel_hash = elf_section_data (o)->rel_hashes;
2086 rel_hdr = &elf_section_data (o)->rel_hdr;
2087 for (i = 0; i < o->reloc_count; i++, rel_hash++)
2088 {
2089 if (*rel_hash == NULL)
2090 continue;
2091
2092 BFD_ASSERT ((*rel_hash)->indx >= 0);
2093
2094 if (rel_hdr->sh_entsize == sizeof (Elf_External_Rel))
2095 {
2096 Elf_External_Rel *erel;
2097 Elf_Internal_Rel irel;
2098
2099 erel = (Elf_External_Rel *) rel_hdr->contents + i;
2100 elf_swap_reloc_in (abfd, erel, &irel);
2101 irel.r_info = ELF_R_INFO ((*rel_hash)->indx,
2102 ELF_R_TYPE (irel.r_info));
2103 elf_swap_reloc_out (abfd, &irel, erel);
2104 }
2105 else
2106 {
2107 Elf_External_Rela *erela;
2108 Elf_Internal_Rela irela;
2109
2110 BFD_ASSERT (rel_hdr->sh_entsize
2111 == sizeof (Elf_External_Rela));
2112
2113 erela = (Elf_External_Rela *) rel_hdr->contents + i;
2114 elf_swap_reloca_in (abfd, erela, &irela);
2115 irela.r_info = ELF_R_INFO ((*rel_hash)->indx,
2116 ELF_R_TYPE (irela.r_info));
2117 elf_swap_reloca_out (abfd, &irela, erela);
2118 }
2119 }
2120
2121 /* Set the reloc_count field to 0 to prevent write_relocs from
2122 trying to swap the relocs out itself. */
2123 o->reloc_count = 0;
2124 }
2125
2126 /* If we are linking against a dynamic object, or generating a
2127 shared library, finish up the dynamic linking information. */
2128 if (dynamic)
2129 {
2130 Elf_External_Dyn *dyncon, *dynconend;
2131
2132 /* Fix up .dynamic entries. */
2133 o = bfd_get_section_by_name (dynobj, ".dynamic");
2134 BFD_ASSERT (o != NULL);
2135
2136 dyncon = (Elf_External_Dyn *) o->contents;
2137 dynconend = (Elf_External_Dyn *) (o->contents + o->_raw_size);
2138 for (; dyncon < dynconend; dyncon++)
2139 {
2140 Elf_Internal_Dyn dyn;
2141 const char *name;
2142 unsigned int type;
2143
2144 elf_swap_dyn_in (dynobj, dyncon, &dyn);
2145
2146 switch (dyn.d_tag)
2147 {
2148 default:
2149 break;
2150
2151 /* SVR4 linkers seem to set DT_INIT and DT_FINI based on
2152 magic _init and _fini symbols. This is pretty ugly,
2153 but we are compatible. */
2154 case DT_INIT:
2155 name = "_init";
2156 goto get_sym;
2157 case DT_FINI:
2158 name = "_fini";
2159 get_sym:
2160 {
2161 struct elf_link_hash_entry *h;
2162
2163 h = elf_link_hash_lookup (elf_hash_table (info), name,
2164 false, false, true);
2165 if (h != NULL
2166 && (h->root.type == bfd_link_hash_defined
2167 || h->root.type == bfd_link_hash_defweak))
2168 {
2169 dyn.d_un.d_val = h->root.u.def.value;
2170 o = h->root.u.def.section;
2171 if (o->output_section != NULL)
2172 dyn.d_un.d_val += (o->output_section->vma
2173 + o->output_offset);
2174 else
2175 {
2176 /* The symbol is imported from another shared
2177 library and does not apply to this one. */
2178 dyn.d_un.d_val = 0;
2179 }
2180
2181 elf_swap_dyn_out (dynobj, &dyn, dyncon);
2182 }
2183 }
2184 break;
2185
2186 case DT_HASH:
2187 name = ".hash";
2188 goto get_vma;
2189 case DT_STRTAB:
2190 name = ".dynstr";
2191 goto get_vma;
2192 case DT_SYMTAB:
2193 name = ".dynsym";
2194 get_vma:
2195 o = bfd_get_section_by_name (abfd, name);
2196 BFD_ASSERT (o != NULL);
2197 dyn.d_un.d_ptr = o->vma;
2198 elf_swap_dyn_out (dynobj, &dyn, dyncon);
2199 break;
2200
2201 case DT_REL:
2202 case DT_RELA:
2203 case DT_RELSZ:
2204 case DT_RELASZ:
2205 if (dyn.d_tag == DT_REL || dyn.d_tag == DT_RELSZ)
2206 type = SHT_REL;
2207 else
2208 type = SHT_RELA;
2209 dyn.d_un.d_val = 0;
2210 for (i = 1; i < elf_elfheader (abfd)->e_shnum; i++)
2211 {
2212 Elf_Internal_Shdr *hdr;
2213
2214 hdr = elf_elfsections (abfd)[i];
2215 if (hdr->sh_type == type
2216 && (hdr->sh_flags & SHF_ALLOC) != 0)
2217 {
2218 if (dyn.d_tag == DT_RELSZ || dyn.d_tag == DT_RELASZ)
2219 dyn.d_un.d_val += hdr->sh_size;
2220 else
2221 {
2222 if (dyn.d_un.d_val == 0
2223 || hdr->sh_addr < dyn.d_un.d_val)
2224 dyn.d_un.d_val = hdr->sh_addr;
2225 }
2226 }
2227 }
2228 elf_swap_dyn_out (dynobj, &dyn, dyncon);
2229 break;
2230 }
2231 }
2232 }
2233
2234 /* If we have created any dynamic sections, then output them. */
2235 if (dynobj != NULL)
2236 {
2237 if (! (*bed->elf_backend_finish_dynamic_sections) (abfd, info))
2238 goto error_return;
2239
2240 for (o = dynobj->sections; o != NULL; o = o->next)
2241 {
2242 if ((o->flags & SEC_HAS_CONTENTS) == 0
2243 || o->_raw_size == 0)
2244 continue;
2245 if ((o->flags & SEC_IN_MEMORY) == 0)
2246 {
2247 /* At this point, we are only interested in sections
2248 created by elf_link_create_dynamic_sections. FIXME:
2249 This test is fragile. */
2250 continue;
2251 }
2252 if ((elf_section_data (o->output_section)->this_hdr.sh_type
2253 != SHT_STRTAB)
2254 || strcmp (bfd_get_section_name (abfd, o), ".dynstr") != 0)
2255 {
2256 if (! bfd_set_section_contents (abfd, o->output_section,
2257 o->contents, o->output_offset,
2258 o->_raw_size))
2259 goto error_return;
2260 }
2261 else
2262 {
2263 file_ptr off;
2264
2265 /* The contents of the .dynstr section are actually in a
2266 stringtab. */
2267 off = elf_section_data (o->output_section)->this_hdr.sh_offset;
2268 if (bfd_seek (abfd, off, SEEK_SET) != 0
2269 || ! _bfd_stringtab_emit (abfd,
2270 elf_hash_table (info)->dynstr))
2271 goto error_return;
2272 }
2273 }
2274 }
2275
2276 if (finfo.symstrtab != NULL)
2277 _bfd_stringtab_free (finfo.symstrtab);
2278 if (finfo.contents != NULL)
2279 free (finfo.contents);
2280 if (finfo.external_relocs != NULL)
2281 free (finfo.external_relocs);
2282 if (finfo.internal_relocs != NULL)
2283 free (finfo.internal_relocs);
2284 if (finfo.external_syms != NULL)
2285 free (finfo.external_syms);
2286 if (finfo.internal_syms != NULL)
2287 free (finfo.internal_syms);
2288 if (finfo.indices != NULL)
2289 free (finfo.indices);
2290 if (finfo.sections != NULL)
2291 free (finfo.sections);
2292 if (finfo.symbuf != NULL)
2293 free (finfo.symbuf);
2294 for (o = abfd->sections; o != NULL; o = o->next)
2295 {
2296 if ((o->flags & SEC_RELOC) != 0
2297 && elf_section_data (o)->rel_hashes != NULL)
2298 free (elf_section_data (o)->rel_hashes);
2299 }
2300
2301 elf_tdata (abfd)->linker = true;
2302
2303 return true;
2304
2305 error_return:
2306 if (finfo.symstrtab != NULL)
2307 _bfd_stringtab_free (finfo.symstrtab);
2308 if (finfo.contents != NULL)
2309 free (finfo.contents);
2310 if (finfo.external_relocs != NULL)
2311 free (finfo.external_relocs);
2312 if (finfo.internal_relocs != NULL)
2313 free (finfo.internal_relocs);
2314 if (finfo.external_syms != NULL)
2315 free (finfo.external_syms);
2316 if (finfo.internal_syms != NULL)
2317 free (finfo.internal_syms);
2318 if (finfo.indices != NULL)
2319 free (finfo.indices);
2320 if (finfo.sections != NULL)
2321 free (finfo.sections);
2322 if (finfo.symbuf != NULL)
2323 free (finfo.symbuf);
2324 for (o = abfd->sections; o != NULL; o = o->next)
2325 {
2326 if ((o->flags & SEC_RELOC) != 0
2327 && elf_section_data (o)->rel_hashes != NULL)
2328 free (elf_section_data (o)->rel_hashes);
2329 }
2330
2331 return false;
2332 }
2333
2334 /* Add a symbol to the output symbol table. */
2335
2336 static boolean
2337 elf_link_output_sym (finfo, name, elfsym, input_sec)
2338 struct elf_final_link_info *finfo;
2339 const char *name;
2340 Elf_Internal_Sym *elfsym;
2341 asection *input_sec;
2342 {
2343 boolean (*output_symbol_hook) PARAMS ((bfd *,
2344 struct bfd_link_info *info,
2345 const char *,
2346 Elf_Internal_Sym *,
2347 asection *));
2348
2349 output_symbol_hook = get_elf_backend_data (finfo->output_bfd)->
2350 elf_backend_link_output_symbol_hook;
2351 if (output_symbol_hook != NULL)
2352 {
2353 if (! ((*output_symbol_hook)
2354 (finfo->output_bfd, finfo->info, name, elfsym, input_sec)))
2355 return false;
2356 }
2357
2358 if (name == (const char *) NULL || *name == '\0')
2359 elfsym->st_name = 0;
2360 else
2361 {
2362 elfsym->st_name = (unsigned long) _bfd_stringtab_add (finfo->symstrtab,
2363 name, true,
2364 false);
2365 if (elfsym->st_name == (unsigned long) -1)
2366 return false;
2367 }
2368
2369 if (finfo->symbuf_count >= finfo->symbuf_size)
2370 {
2371 if (! elf_link_flush_output_syms (finfo))
2372 return false;
2373 }
2374
2375 elf_swap_symbol_out (finfo->output_bfd, elfsym,
2376 (PTR) (finfo->symbuf + finfo->symbuf_count));
2377 ++finfo->symbuf_count;
2378
2379 ++finfo->output_bfd->symcount;
2380
2381 return true;
2382 }
2383
2384 /* Flush the output symbols to the file. */
2385
2386 static boolean
2387 elf_link_flush_output_syms (finfo)
2388 struct elf_final_link_info *finfo;
2389 {
2390 Elf_Internal_Shdr *symtab;
2391
2392 symtab = &elf_tdata (finfo->output_bfd)->symtab_hdr;
2393
2394 if (bfd_seek (finfo->output_bfd, symtab->sh_offset + symtab->sh_size,
2395 SEEK_SET) != 0
2396 || (bfd_write ((PTR) finfo->symbuf, finfo->symbuf_count,
2397 sizeof (Elf_External_Sym), finfo->output_bfd)
2398 != finfo->symbuf_count * sizeof (Elf_External_Sym)))
2399 return false;
2400
2401 symtab->sh_size += finfo->symbuf_count * sizeof (Elf_External_Sym);
2402
2403 finfo->symbuf_count = 0;
2404
2405 return true;
2406 }
2407
2408 /* Add an external symbol to the symbol table. This is called from
2409 the hash table traversal routine. */
2410
2411 static boolean
2412 elf_link_output_extsym (h, data)
2413 struct elf_link_hash_entry *h;
2414 PTR data;
2415 {
2416 struct elf_finfo_failed *eif = (struct elf_finfo_failed *) data;
2417 struct elf_final_link_info *finfo = eif->finfo;
2418 boolean strip;
2419 Elf_Internal_Sym sym;
2420 asection *input_sec;
2421
2422 /* If we are not creating a shared library, and this symbol is
2423 referenced by a shared library but is not defined anywhere, then
2424 warn that it is undefined. If we do not do this, the runtime
2425 linker will complain that the symbol is undefined when the
2426 program is run. We don't have to worry about symbols that are
2427 referenced by regular files, because we will already have issued
2428 warnings for them. */
2429 if (! finfo->info->relocateable
2430 && ! finfo->info->shared
2431 && h->root.type == bfd_link_hash_undefined
2432 && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) != 0
2433 && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) == 0)
2434 {
2435 if (! ((*finfo->info->callbacks->undefined_symbol)
2436 (finfo->info, h->root.root.string, h->root.u.undef.abfd,
2437 (asection *) NULL, 0)))
2438 {
2439 eif->failed = true;
2440 return false;
2441 }
2442 }
2443
2444 /* We don't want to output symbols that have never been mentioned by
2445 a regular file, or that we have been told to strip. However, if
2446 h->indx is set to -2, the symbol is used by a reloc and we must
2447 output it. */
2448 if (h->indx == -2)
2449 strip = false;
2450 else if (((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0
2451 || (h->elf_link_hash_flags & ELF_LINK_HASH_REF_DYNAMIC) != 0)
2452 && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0
2453 && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) == 0)
2454 strip = true;
2455 else if (finfo->info->strip == strip_all
2456 || (finfo->info->strip == strip_some
2457 && bfd_hash_lookup (finfo->info->keep_hash,
2458 h->root.root.string,
2459 false, false) == NULL))
2460 strip = true;
2461 else
2462 strip = false;
2463
2464 /* If we're stripping it, and it's not a dynamic symbol, there's
2465 nothing else to do. */
2466 if (strip && h->dynindx == -1)
2467 return true;
2468
2469 sym.st_value = 0;
2470 sym.st_size = h->size;
2471 sym.st_other = 0;
2472 if (h->root.type == bfd_link_hash_undefweak
2473 || h->root.type == bfd_link_hash_defweak)
2474 sym.st_info = ELF_ST_INFO (STB_WEAK, h->type);
2475 else
2476 sym.st_info = ELF_ST_INFO (STB_GLOBAL, h->type);
2477
2478 switch (h->root.type)
2479 {
2480 default:
2481 case bfd_link_hash_new:
2482 abort ();
2483 return false;
2484
2485 case bfd_link_hash_undefined:
2486 input_sec = bfd_und_section_ptr;
2487 sym.st_shndx = SHN_UNDEF;
2488 break;
2489
2490 case bfd_link_hash_undefweak:
2491 input_sec = bfd_und_section_ptr;
2492 sym.st_shndx = SHN_UNDEF;
2493 break;
2494
2495 case bfd_link_hash_defined:
2496 case bfd_link_hash_defweak:
2497 {
2498 input_sec = h->root.u.def.section;
2499 if (input_sec->output_section != NULL)
2500 {
2501 sym.st_shndx =
2502 _bfd_elf_section_from_bfd_section (finfo->output_bfd,
2503 input_sec->output_section);
2504 if (sym.st_shndx == (unsigned short) -1)
2505 {
2506 eif->failed = true;
2507 return false;
2508 }
2509
2510 /* ELF symbols in relocateable files are section relative,
2511 but in nonrelocateable files they are virtual
2512 addresses. */
2513 sym.st_value = h->root.u.def.value + input_sec->output_offset;
2514 if (! finfo->info->relocateable)
2515 sym.st_value += input_sec->output_section->vma;
2516 }
2517 else
2518 {
2519 BFD_ASSERT ((bfd_get_flavour (input_sec->owner)
2520 == bfd_target_elf_flavour)
2521 && elf_elfheader (input_sec->owner)->e_type == ET_DYN);
2522 sym.st_shndx = SHN_UNDEF;
2523 input_sec = bfd_und_section_ptr;
2524 }
2525 }
2526 break;
2527
2528 case bfd_link_hash_common:
2529 input_sec = bfd_com_section_ptr;
2530 sym.st_shndx = SHN_COMMON;
2531 sym.st_value = 1 << h->root.u.c.p->alignment_power;
2532 break;
2533
2534 case bfd_link_hash_indirect:
2535 case bfd_link_hash_warning:
2536 return (elf_link_output_extsym
2537 ((struct elf_link_hash_entry *) h->root.u.i.link, data));
2538 }
2539
2540 /* If this symbol should be put in the .dynsym section, then put it
2541 there now. We have already know the symbol index. We also fill
2542 in the entry in the .hash section. */
2543 if (h->dynindx != -1
2544 && elf_hash_table (finfo->info)->dynamic_sections_created)
2545 {
2546 struct elf_backend_data *bed;
2547 size_t bucketcount;
2548 size_t bucket;
2549 bfd_byte *bucketpos;
2550 bfd_vma chain;
2551
2552 sym.st_name = h->dynstr_index;
2553
2554 /* Give the processor backend a chance to tweak the symbol
2555 value, and also to finish up anything that needs to be done
2556 for this symbol. */
2557 bed = get_elf_backend_data (finfo->output_bfd);
2558 if (! ((*bed->elf_backend_finish_dynamic_symbol)
2559 (finfo->output_bfd, finfo->info, h, &sym)))
2560 {
2561 eif->failed = true;
2562 return false;
2563 }
2564
2565 elf_swap_symbol_out (finfo->output_bfd, &sym,
2566 (PTR) (((Elf_External_Sym *)
2567 finfo->dynsym_sec->contents)
2568 + h->dynindx));
2569
2570 bucketcount = elf_hash_table (finfo->info)->bucketcount;
2571 bucket = (bfd_elf_hash ((const unsigned char *) h->root.root.string)
2572 % bucketcount);
2573 bucketpos = ((bfd_byte *) finfo->hash_sec->contents
2574 + (bucket + 2) * (ARCH_SIZE / 8));
2575 chain = get_word (finfo->output_bfd, bucketpos);
2576 put_word (finfo->output_bfd, h->dynindx, bucketpos);
2577 put_word (finfo->output_bfd, chain,
2578 ((bfd_byte *) finfo->hash_sec->contents
2579 + (bucketcount + 2 + h->dynindx) * (ARCH_SIZE / 8)));
2580 }
2581
2582 /* If we're stripping it, then it was just a dynamic symbol, and
2583 there's nothing else to do. */
2584 if (strip)
2585 return true;
2586
2587 h->indx = finfo->output_bfd->symcount;
2588
2589 if (! elf_link_output_sym (finfo, h->root.root.string, &sym, input_sec))
2590 {
2591 eif->failed = true;
2592 return false;
2593 }
2594
2595 return true;
2596 }
2597
2598 /* Link an input file into the linker output file. This function
2599 handles all the sections and relocations of the input file at once.
2600 This is so that we only have to read the local symbols once, and
2601 don't have to keep them in memory. */
2602
2603 static boolean
2604 elf_link_input_bfd (finfo, input_bfd)
2605 struct elf_final_link_info *finfo;
2606 bfd *input_bfd;
2607 {
2608 boolean (*relocate_section) PARAMS ((bfd *, struct bfd_link_info *,
2609 bfd *, asection *, bfd_byte *,
2610 Elf_Internal_Rela *,
2611 Elf_Internal_Sym *, asection **));
2612 bfd *output_bfd;
2613 Elf_Internal_Shdr *symtab_hdr;
2614 size_t locsymcount;
2615 size_t extsymoff;
2616 Elf_External_Sym *esym;
2617 Elf_External_Sym *esymend;
2618 Elf_Internal_Sym *isym;
2619 long *pindex;
2620 asection **ppsection;
2621 asection *o;
2622
2623 output_bfd = finfo->output_bfd;
2624 relocate_section =
2625 get_elf_backend_data (output_bfd)->elf_backend_relocate_section;
2626
2627 /* If this is a dynamic object, we don't want to do anything here:
2628 we don't want the local symbols, and we don't want the section
2629 contents. */
2630 if (elf_elfheader (input_bfd)->e_type == ET_DYN)
2631 return true;
2632
2633 symtab_hdr = &elf_tdata (input_bfd)->symtab_hdr;
2634 if (elf_bad_symtab (input_bfd))
2635 {
2636 locsymcount = symtab_hdr->sh_size / sizeof (Elf_External_Sym);
2637 extsymoff = 0;
2638 }
2639 else
2640 {
2641 locsymcount = symtab_hdr->sh_info;
2642 extsymoff = symtab_hdr->sh_info;
2643 }
2644
2645 /* Read the local symbols. */
2646 if (locsymcount > 0
2647 && (bfd_seek (input_bfd, symtab_hdr->sh_offset, SEEK_SET) != 0
2648 || (bfd_read (finfo->external_syms, sizeof (Elf_External_Sym),
2649 locsymcount, input_bfd)
2650 != locsymcount * sizeof (Elf_External_Sym))))
2651 return false;
2652
2653 /* Swap in the local symbols and write out the ones which we know
2654 are going into the output file. */
2655 esym = finfo->external_syms;
2656 esymend = esym + locsymcount;
2657 isym = finfo->internal_syms;
2658 pindex = finfo->indices;
2659 ppsection = finfo->sections;
2660 for (; esym < esymend; esym++, isym++, pindex++, ppsection++)
2661 {
2662 asection *isec;
2663 const char *name;
2664 Elf_Internal_Sym osym;
2665
2666 elf_swap_symbol_in (input_bfd, esym, isym);
2667 *pindex = -1;
2668
2669 if (elf_bad_symtab (input_bfd))
2670 {
2671 if (ELF_ST_BIND (isym->st_info) != STB_LOCAL)
2672 {
2673 *ppsection = NULL;
2674 continue;
2675 }
2676 }
2677
2678 if (isym->st_shndx == SHN_UNDEF)
2679 isec = bfd_und_section_ptr;
2680 else if (isym->st_shndx > 0 && isym->st_shndx < SHN_LORESERVE)
2681 isec = section_from_elf_index (input_bfd, isym->st_shndx);
2682 else if (isym->st_shndx == SHN_ABS)
2683 isec = bfd_abs_section_ptr;
2684 else if (isym->st_shndx == SHN_COMMON)
2685 isec = bfd_com_section_ptr;
2686 else
2687 {
2688 /* Who knows? */
2689 isec = NULL;
2690 }
2691
2692 *ppsection = isec;
2693
2694 /* Don't output the first, undefined, symbol. */
2695 if (esym == finfo->external_syms)
2696 continue;
2697
2698 /* If we are stripping all symbols, we don't want to output this
2699 one. */
2700 if (finfo->info->strip == strip_all)
2701 continue;
2702
2703 /* We never output section symbols. Instead, we use the section
2704 symbol of the corresponding section in the output file. */
2705 if (ELF_ST_TYPE (isym->st_info) == STT_SECTION)
2706 continue;
2707
2708 /* If we are discarding all local symbols, we don't want to
2709 output this one. If we are generating a relocateable output
2710 file, then some of the local symbols may be required by
2711 relocs; we output them below as we discover that they are
2712 needed. */
2713 if (finfo->info->discard == discard_all)
2714 continue;
2715
2716 /* Get the name of the symbol. */
2717 name = bfd_elf_string_from_elf_section (input_bfd, symtab_hdr->sh_link,
2718 isym->st_name);
2719 if (name == NULL)
2720 return false;
2721
2722 /* See if we are discarding symbols with this name. */
2723 if ((finfo->info->strip == strip_some
2724 && (bfd_hash_lookup (finfo->info->keep_hash, name, false, false)
2725 == NULL))
2726 || (finfo->info->discard == discard_l
2727 && strncmp (name, finfo->info->lprefix,
2728 finfo->info->lprefix_len) == 0))
2729 continue;
2730
2731 /* If we get here, we are going to output this symbol. */
2732
2733 osym = *isym;
2734
2735 /* Adjust the section index for the output file. */
2736 osym.st_shndx = _bfd_elf_section_from_bfd_section (output_bfd,
2737 isec->output_section);
2738 if (osym.st_shndx == (unsigned short) -1)
2739 return false;
2740
2741 *pindex = output_bfd->symcount;
2742
2743 /* ELF symbols in relocateable files are section relative, but
2744 in executable files they are virtual addresses. Note that
2745 this code assumes that all ELF sections have an associated
2746 BFD section with a reasonable value for output_offset; below
2747 we assume that they also have a reasonable value for
2748 output_section. Any special sections must be set up to meet
2749 these requirements. */
2750 osym.st_value += isec->output_offset;
2751 if (! finfo->info->relocateable)
2752 osym.st_value += isec->output_section->vma;
2753
2754 if (! elf_link_output_sym (finfo, name, &osym, isec))
2755 return false;
2756 }
2757
2758 /* Relocate the contents of each section. */
2759 for (o = input_bfd->sections; o != NULL; o = o->next)
2760 {
2761 if ((o->flags & SEC_HAS_CONTENTS) == 0)
2762 continue;
2763
2764 if ((o->flags & SEC_IN_MEMORY) != 0
2765 && input_bfd == elf_hash_table (finfo->info)->dynobj)
2766 {
2767 /* Section was created by elf_link_create_dynamic_sections.
2768 FIXME: This test is fragile. */
2769 continue;
2770 }
2771
2772 /* Read the contents of the section. */
2773 if (! bfd_get_section_contents (input_bfd, o, finfo->contents,
2774 (file_ptr) 0, o->_raw_size))
2775 return false;
2776
2777 if ((o->flags & SEC_RELOC) != 0)
2778 {
2779 Elf_Internal_Rela *internal_relocs;
2780
2781 /* Get the swapped relocs. */
2782 internal_relocs = elf_link_read_relocs (input_bfd, o,
2783 finfo->external_relocs,
2784 finfo->internal_relocs,
2785 false);
2786 if (internal_relocs == NULL
2787 && o->reloc_count > 0)
2788 return false;
2789
2790 /* Relocate the section by invoking a back end routine.
2791
2792 The back end routine is responsible for adjusting the
2793 section contents as necessary, and (if using Rela relocs
2794 and generating a relocateable output file) adjusting the
2795 reloc addend as necessary.
2796
2797 The back end routine does not have to worry about setting
2798 the reloc address or the reloc symbol index.
2799
2800 The back end routine is given a pointer to the swapped in
2801 internal symbols, and can access the hash table entries
2802 for the external symbols via elf_sym_hashes (input_bfd).
2803
2804 When generating relocateable output, the back end routine
2805 must handle STB_LOCAL/STT_SECTION symbols specially. The
2806 output symbol is going to be a section symbol
2807 corresponding to the output section, which will require
2808 the addend to be adjusted. */
2809
2810 if (! (*relocate_section) (output_bfd, finfo->info,
2811 input_bfd, o,
2812 finfo->contents,
2813 internal_relocs,
2814 finfo->internal_syms,
2815 finfo->sections))
2816 return false;
2817
2818 if (finfo->info->relocateable)
2819 {
2820 Elf_Internal_Rela *irela;
2821 Elf_Internal_Rela *irelaend;
2822 struct elf_link_hash_entry **rel_hash;
2823 Elf_Internal_Shdr *input_rel_hdr;
2824 Elf_Internal_Shdr *output_rel_hdr;
2825
2826 /* Adjust the reloc addresses and symbol indices. */
2827
2828 irela = internal_relocs;
2829 irelaend = irela + o->reloc_count;
2830 rel_hash = (elf_section_data (o->output_section)->rel_hashes
2831 + o->output_section->reloc_count);
2832 for (; irela < irelaend; irela++, rel_hash++)
2833 {
2834 unsigned long r_symndx;
2835 Elf_Internal_Sym *isym;
2836 asection *sec;
2837
2838 irela->r_offset += o->output_offset;
2839
2840 r_symndx = ELF_R_SYM (irela->r_info);
2841
2842 if (r_symndx == 0)
2843 continue;
2844
2845 if (r_symndx >= locsymcount
2846 || (elf_bad_symtab (input_bfd)
2847 && finfo->sections[r_symndx] == NULL))
2848 {
2849 long indx;
2850
2851 /* This is a reloc against a global symbol. We
2852 have not yet output all the local symbols, so
2853 we do not know the symbol index of any global
2854 symbol. We set the rel_hash entry for this
2855 reloc to point to the global hash table entry
2856 for this symbol. The symbol index is then
2857 set at the end of elf_bfd_final_link. */
2858 indx = r_symndx - extsymoff;
2859 *rel_hash = elf_sym_hashes (input_bfd)[indx];
2860
2861 /* Setting the index to -2 tells
2862 elf_link_output_extsym that this symbol is
2863 used by a reloc. */
2864 BFD_ASSERT ((*rel_hash)->indx < 0);
2865 (*rel_hash)->indx = -2;
2866
2867 continue;
2868 }
2869
2870 /* This is a reloc against a local symbol. */
2871
2872 *rel_hash = NULL;
2873 isym = finfo->internal_syms + r_symndx;
2874 sec = finfo->sections[r_symndx];
2875 if (ELF_ST_TYPE (isym->st_info) == STT_SECTION)
2876 {
2877 /* I suppose the backend ought to fill in the
2878 section of any STT_SECTION symbol against a
2879 processor specific section. */
2880 if (sec != NULL && bfd_is_abs_section (sec))
2881 r_symndx = 0;
2882 else if (sec == NULL || sec->owner == NULL)
2883 {
2884 bfd_set_error (bfd_error_bad_value);
2885 return false;
2886 }
2887 else
2888 {
2889 r_symndx = sec->output_section->target_index;
2890 BFD_ASSERT (r_symndx != 0);
2891 }
2892 }
2893 else
2894 {
2895 if (finfo->indices[r_symndx] == -1)
2896 {
2897 unsigned long link;
2898 const char *name;
2899 asection *osec;
2900
2901 if (finfo->info->strip == strip_all)
2902 {
2903 /* You can't do ld -r -s. */
2904 bfd_set_error (bfd_error_invalid_operation);
2905 return false;
2906 }
2907
2908 /* This symbol was skipped earlier, but
2909 since it is needed by a reloc, we
2910 must output it now. */
2911 link = symtab_hdr->sh_link;
2912 name = bfd_elf_string_from_elf_section (input_bfd,
2913 link,
2914 isym->st_name);
2915 if (name == NULL)
2916 return false;
2917
2918 osec = sec->output_section;
2919 isym->st_shndx =
2920 _bfd_elf_section_from_bfd_section (output_bfd,
2921 osec);
2922 if (isym->st_shndx == (unsigned short) -1)
2923 return false;
2924
2925 isym->st_value += sec->output_offset;
2926 if (! finfo->info->relocateable)
2927 isym->st_value += osec->vma;
2928
2929 finfo->indices[r_symndx] = output_bfd->symcount;
2930
2931 if (! elf_link_output_sym (finfo, name, isym, sec))
2932 return false;
2933 }
2934
2935 r_symndx = finfo->indices[r_symndx];
2936 }
2937
2938 irela->r_info = ELF_R_INFO (r_symndx,
2939 ELF_R_TYPE (irela->r_info));
2940 }
2941
2942 /* Swap out the relocs. */
2943 input_rel_hdr = &elf_section_data (o)->rel_hdr;
2944 output_rel_hdr = &elf_section_data (o->output_section)->rel_hdr;
2945 BFD_ASSERT (output_rel_hdr->sh_entsize
2946 == input_rel_hdr->sh_entsize);
2947 irela = internal_relocs;
2948 irelaend = irela + o->reloc_count;
2949 if (input_rel_hdr->sh_entsize == sizeof (Elf_External_Rel))
2950 {
2951 Elf_External_Rel *erel;
2952
2953 erel = ((Elf_External_Rel *) output_rel_hdr->contents
2954 + o->output_section->reloc_count);
2955 for (; irela < irelaend; irela++, erel++)
2956 {
2957 Elf_Internal_Rel irel;
2958
2959 irel.r_offset = irela->r_offset;
2960 irel.r_info = irela->r_info;
2961 BFD_ASSERT (irela->r_addend == 0);
2962 elf_swap_reloc_out (output_bfd, &irel, erel);
2963 }
2964 }
2965 else
2966 {
2967 Elf_External_Rela *erela;
2968
2969 BFD_ASSERT (input_rel_hdr->sh_entsize
2970 == sizeof (Elf_External_Rela));
2971 erela = ((Elf_External_Rela *) output_rel_hdr->contents
2972 + o->output_section->reloc_count);
2973 for (; irela < irelaend; irela++, erela++)
2974 elf_swap_reloca_out (output_bfd, irela, erela);
2975 }
2976
2977 o->output_section->reloc_count += o->reloc_count;
2978 }
2979 }
2980
2981 /* Write out the modified section contents. */
2982 if (! bfd_set_section_contents (output_bfd, o->output_section,
2983 finfo->contents, o->output_offset,
2984 (o->_cooked_size != 0
2985 ? o->_cooked_size
2986 : o->_raw_size)))
2987 return false;
2988 }
2989
2990 return true;
2991 }
2992
2993 /* Generate a reloc when linking an ELF file. This is a reloc
2994 requested by the linker, and does come from any input file. This
2995 is used to build constructor and destructor tables when linking
2996 with -Ur. */
2997
2998 static boolean
2999 elf_reloc_link_order (output_bfd, info, output_section, link_order)
3000 bfd *output_bfd;
3001 struct bfd_link_info *info;
3002 asection *output_section;
3003 struct bfd_link_order *link_order;
3004 {
3005 reloc_howto_type *howto;
3006 long indx;
3007 bfd_vma offset;
3008 struct elf_link_hash_entry **rel_hash_ptr;
3009 Elf_Internal_Shdr *rel_hdr;
3010
3011 howto = bfd_reloc_type_lookup (output_bfd, link_order->u.reloc.p->reloc);
3012 if (howto == NULL)
3013 {
3014 bfd_set_error (bfd_error_bad_value);
3015 return false;
3016 }
3017
3018 /* If this is an inplace reloc, we must write the addend into the
3019 object file. */
3020 if (howto->partial_inplace
3021 && link_order->u.reloc.p->addend != 0)
3022 {
3023 bfd_size_type size;
3024 bfd_reloc_status_type rstat;
3025 bfd_byte *buf;
3026 boolean ok;
3027
3028 size = bfd_get_reloc_size (howto);
3029 buf = (bfd_byte *) bfd_zmalloc (size);
3030 if (buf == (bfd_byte *) NULL)
3031 {
3032 bfd_set_error (bfd_error_no_memory);
3033 return false;
3034 }
3035 rstat = _bfd_relocate_contents (howto, output_bfd,
3036 link_order->u.reloc.p->addend, buf);
3037 switch (rstat)
3038 {
3039 case bfd_reloc_ok:
3040 break;
3041 default:
3042 case bfd_reloc_outofrange:
3043 abort ();
3044 case bfd_reloc_overflow:
3045 if (! ((*info->callbacks->reloc_overflow)
3046 (info,
3047 (link_order->type == bfd_section_reloc_link_order
3048 ? bfd_section_name (output_bfd,
3049 link_order->u.reloc.p->u.section)
3050 : link_order->u.reloc.p->u.name),
3051 howto->name, link_order->u.reloc.p->addend,
3052 (bfd *) NULL, (asection *) NULL, (bfd_vma) 0)))
3053 {
3054 free (buf);
3055 return false;
3056 }
3057 break;
3058 }
3059 ok = bfd_set_section_contents (output_bfd, output_section, (PTR) buf,
3060 (file_ptr) link_order->offset, size);
3061 free (buf);
3062 if (! ok)
3063 return false;
3064 }
3065
3066 /* Figure out the symbol index. */
3067 rel_hash_ptr = (elf_section_data (output_section)->rel_hashes
3068 + output_section->reloc_count);
3069 if (link_order->type == bfd_section_reloc_link_order)
3070 {
3071 indx = link_order->u.reloc.p->u.section->target_index;
3072 BFD_ASSERT (indx != 0);
3073 *rel_hash_ptr = NULL;
3074 }
3075 else
3076 {
3077 struct elf_link_hash_entry *h;
3078
3079 h = elf_link_hash_lookup (elf_hash_table (info),
3080 link_order->u.reloc.p->u.name,
3081 false, false, true);
3082 if (h != NULL)
3083 {
3084 /* Setting the index to -2 tells elf_link_output_extsym that
3085 this symbol is used by a reloc. */
3086 h->indx = -2;
3087 *rel_hash_ptr = h;
3088 indx = 0;
3089 }
3090 else
3091 {
3092 if (! ((*info->callbacks->unattached_reloc)
3093 (info, link_order->u.reloc.p->u.name, (bfd *) NULL,
3094 (asection *) NULL, (bfd_vma) 0)))
3095 return false;
3096 indx = 0;
3097 }
3098 }
3099
3100 /* The address of a reloc is relative to the section in a
3101 relocateable file, and is a virtual address in an executable
3102 file. */
3103 offset = link_order->offset;
3104 if (! info->relocateable)
3105 offset += output_section->vma;
3106
3107 rel_hdr = &elf_section_data (output_section)->rel_hdr;
3108
3109 if (rel_hdr->sh_type == SHT_REL)
3110 {
3111 Elf_Internal_Rel irel;
3112 Elf_External_Rel *erel;
3113
3114 irel.r_offset = offset;
3115 irel.r_info = ELF_R_INFO (indx, howto->type);
3116 erel = ((Elf_External_Rel *) rel_hdr->contents
3117 + output_section->reloc_count);
3118 elf_swap_reloc_out (output_bfd, &irel, erel);
3119 }
3120 else
3121 {
3122 Elf_Internal_Rela irela;
3123 Elf_External_Rela *erela;
3124
3125 irela.r_offset = offset;
3126 irela.r_info = ELF_R_INFO (indx, howto->type);
3127 irela.r_addend = link_order->u.reloc.p->addend;
3128 erela = ((Elf_External_Rela *) rel_hdr->contents
3129 + output_section->reloc_count);
3130 elf_swap_reloca_out (output_bfd, &irela, erela);
3131 }
3132
3133 ++output_section->reloc_count;
3134
3135 return true;
3136 }
3137
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