1 /* linker.c -- BFD linker routines
2 Copyright (C) 1993-2014 Free Software Foundation, Inc.
3 Written by Steve Chamberlain and Ian Lance Taylor, Cygnus Support
5 This file is part of BFD, the Binary File Descriptor library.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
20 MA 02110-1301, USA. */
33 The linker uses three special entry points in the BFD target
34 vector. It is not necessary to write special routines for
35 these entry points when creating a new BFD back end, since
36 generic versions are provided. However, writing them can
37 speed up linking and make it use significantly less runtime
40 The first routine creates a hash table used by the other
41 routines. The second routine adds the symbols from an object
42 file to the hash table. The third routine takes all the
43 object files and links them together to create the output
44 file. These routines are designed so that the linker proper
45 does not need to know anything about the symbols in the object
46 files that it is linking. The linker merely arranges the
47 sections as directed by the linker script and lets BFD handle
48 the details of symbols and relocs.
50 The second routine and third routines are passed a pointer to
51 a <<struct bfd_link_info>> structure (defined in
52 <<bfdlink.h>>) which holds information relevant to the link,
53 including the linker hash table (which was created by the
54 first routine) and a set of callback functions to the linker
57 The generic linker routines are in <<linker.c>>, and use the
58 header file <<genlink.h>>. As of this writing, the only back
59 ends which have implemented versions of these routines are
60 a.out (in <<aoutx.h>>) and ECOFF (in <<ecoff.c>>). The a.out
61 routines are used as examples throughout this section.
64 @* Creating a Linker Hash Table::
65 @* Adding Symbols to the Hash Table::
66 @* Performing the Final Link::
70 Creating a Linker Hash Table, Adding Symbols to the Hash Table, Linker Functions, Linker Functions
72 Creating a linker hash table
74 @cindex _bfd_link_hash_table_create in target vector
75 @cindex target vector (_bfd_link_hash_table_create)
76 The linker routines must create a hash table, which must be
77 derived from <<struct bfd_link_hash_table>> described in
78 <<bfdlink.c>>. @xref{Hash Tables}, for information on how to
79 create a derived hash table. This entry point is called using
80 the target vector of the linker output file.
82 The <<_bfd_link_hash_table_create>> entry point must allocate
83 and initialize an instance of the desired hash table. If the
84 back end does not require any additional information to be
85 stored with the entries in the hash table, the entry point may
86 simply create a <<struct bfd_link_hash_table>>. Most likely,
87 however, some additional information will be needed.
89 For example, with each entry in the hash table the a.out
90 linker keeps the index the symbol has in the final output file
91 (this index number is used so that when doing a relocatable
92 link the symbol index used in the output file can be quickly
93 filled in when copying over a reloc). The a.out linker code
94 defines the required structures and functions for a hash table
95 derived from <<struct bfd_link_hash_table>>. The a.out linker
96 hash table is created by the function
97 <<NAME(aout,link_hash_table_create)>>; it simply allocates
98 space for the hash table, initializes it, and returns a
101 When writing the linker routines for a new back end, you will
102 generally not know exactly which fields will be required until
103 you have finished. You should simply create a new hash table
104 which defines no additional fields, and then simply add fields
105 as they become necessary.
108 Adding Symbols to the Hash Table, Performing the Final Link, Creating a Linker Hash Table, Linker Functions
110 Adding symbols to the hash table
112 @cindex _bfd_link_add_symbols in target vector
113 @cindex target vector (_bfd_link_add_symbols)
114 The linker proper will call the <<_bfd_link_add_symbols>>
115 entry point for each object file or archive which is to be
116 linked (typically these are the files named on the command
117 line, but some may also come from the linker script). The
118 entry point is responsible for examining the file. For an
119 object file, BFD must add any relevant symbol information to
120 the hash table. For an archive, BFD must determine which
121 elements of the archive should be used and adding them to the
124 The a.out version of this entry point is
125 <<NAME(aout,link_add_symbols)>>.
128 @* Differing file formats::
129 @* Adding symbols from an object file::
130 @* Adding symbols from an archive::
134 Differing file formats, Adding symbols from an object file, Adding Symbols to the Hash Table, Adding Symbols to the Hash Table
136 Differing file formats
138 Normally all the files involved in a link will be of the same
139 format, but it is also possible to link together different
140 format object files, and the back end must support that. The
141 <<_bfd_link_add_symbols>> entry point is called via the target
142 vector of the file to be added. This has an important
143 consequence: the function may not assume that the hash table
144 is the type created by the corresponding
145 <<_bfd_link_hash_table_create>> vector. All the
146 <<_bfd_link_add_symbols>> function can assume about the hash
147 table is that it is derived from <<struct
148 bfd_link_hash_table>>.
150 Sometimes the <<_bfd_link_add_symbols>> function must store
151 some information in the hash table entry to be used by the
152 <<_bfd_final_link>> function. In such a case the output bfd
153 xvec must be checked to make sure that the hash table was
154 created by an object file of the same format.
156 The <<_bfd_final_link>> routine must be prepared to handle a
157 hash entry without any extra information added by the
158 <<_bfd_link_add_symbols>> function. A hash entry without
159 extra information will also occur when the linker script
160 directs the linker to create a symbol. Note that, regardless
161 of how a hash table entry is added, all the fields will be
162 initialized to some sort of null value by the hash table entry
163 initialization function.
165 See <<ecoff_link_add_externals>> for an example of how to
166 check the output bfd before saving information (in this
167 case, the ECOFF external symbol debugging information) in a
171 Adding symbols from an object file, Adding symbols from an archive, Differing file formats, Adding Symbols to the Hash Table
173 Adding symbols from an object file
175 When the <<_bfd_link_add_symbols>> routine is passed an object
176 file, it must add all externally visible symbols in that
177 object file to the hash table. The actual work of adding the
178 symbol to the hash table is normally handled by the function
179 <<_bfd_generic_link_add_one_symbol>>. The
180 <<_bfd_link_add_symbols>> routine is responsible for reading
181 all the symbols from the object file and passing the correct
182 information to <<_bfd_generic_link_add_one_symbol>>.
184 The <<_bfd_link_add_symbols>> routine should not use
185 <<bfd_canonicalize_symtab>> to read the symbols. The point of
186 providing this routine is to avoid the overhead of converting
187 the symbols into generic <<asymbol>> structures.
189 @findex _bfd_generic_link_add_one_symbol
190 <<_bfd_generic_link_add_one_symbol>> handles the details of
191 combining common symbols, warning about multiple definitions,
192 and so forth. It takes arguments which describe the symbol to
193 add, notably symbol flags, a section, and an offset. The
194 symbol flags include such things as <<BSF_WEAK>> or
195 <<BSF_INDIRECT>>. The section is a section in the object
196 file, or something like <<bfd_und_section_ptr>> for an undefined
197 symbol or <<bfd_com_section_ptr>> for a common symbol.
199 If the <<_bfd_final_link>> routine is also going to need to
200 read the symbol information, the <<_bfd_link_add_symbols>>
201 routine should save it somewhere attached to the object file
202 BFD. However, the information should only be saved if the
203 <<keep_memory>> field of the <<info>> argument is TRUE, so
204 that the <<-no-keep-memory>> linker switch is effective.
206 The a.out function which adds symbols from an object file is
207 <<aout_link_add_object_symbols>>, and most of the interesting
208 work is in <<aout_link_add_symbols>>. The latter saves
209 pointers to the hash tables entries created by
210 <<_bfd_generic_link_add_one_symbol>> indexed by symbol number,
211 so that the <<_bfd_final_link>> routine does not have to call
212 the hash table lookup routine to locate the entry.
215 Adding symbols from an archive, , Adding symbols from an object file, Adding Symbols to the Hash Table
217 Adding symbols from an archive
219 When the <<_bfd_link_add_symbols>> routine is passed an
220 archive, it must look through the symbols defined by the
221 archive and decide which elements of the archive should be
222 included in the link. For each such element it must call the
223 <<add_archive_element>> linker callback, and it must add the
224 symbols from the object file to the linker hash table. (The
225 callback may in fact indicate that a replacement BFD should be
226 used, in which case the symbols from that BFD should be added
227 to the linker hash table instead.)
229 @findex _bfd_generic_link_add_archive_symbols
230 In most cases the work of looking through the symbols in the
231 archive should be done by the
232 <<_bfd_generic_link_add_archive_symbols>> function.
233 <<_bfd_generic_link_add_archive_symbols>> is passed a function
234 to call to make the final decision about adding an archive
235 element to the link and to do the actual work of adding the
236 symbols to the linker hash table. If the element is to
237 be included, the <<add_archive_element>> linker callback
238 routine must be called with the element as an argument, and
239 the element's symbols must be added to the linker hash table
240 just as though the element had itself been passed to the
241 <<_bfd_link_add_symbols>> function.
243 When the a.out <<_bfd_link_add_symbols>> function receives an
244 archive, it calls <<_bfd_generic_link_add_archive_symbols>>
245 passing <<aout_link_check_archive_element>> as the function
246 argument. <<aout_link_check_archive_element>> calls
247 <<aout_link_check_ar_symbols>>. If the latter decides to add
248 the element (an element is only added if it provides a real,
249 non-common, definition for a previously undefined or common
250 symbol) it calls the <<add_archive_element>> callback and then
251 <<aout_link_check_archive_element>> calls
252 <<aout_link_add_symbols>> to actually add the symbols to the
253 linker hash table - possibly those of a substitute BFD, if the
254 <<add_archive_element>> callback avails itself of that option.
256 The ECOFF back end is unusual in that it does not normally
257 call <<_bfd_generic_link_add_archive_symbols>>, because ECOFF
258 archives already contain a hash table of symbols. The ECOFF
259 back end searches the archive itself to avoid the overhead of
260 creating a new hash table.
263 Performing the Final Link, , Adding Symbols to the Hash Table, Linker Functions
265 Performing the final link
267 @cindex _bfd_link_final_link in target vector
268 @cindex target vector (_bfd_final_link)
269 When all the input files have been processed, the linker calls
270 the <<_bfd_final_link>> entry point of the output BFD. This
271 routine is responsible for producing the final output file,
272 which has several aspects. It must relocate the contents of
273 the input sections and copy the data into the output sections.
274 It must build an output symbol table including any local
275 symbols from the input files and the global symbols from the
276 hash table. When producing relocatable output, it must
277 modify the input relocs and write them into the output file.
278 There may also be object format dependent work to be done.
280 The linker will also call the <<write_object_contents>> entry
281 point when the BFD is closed. The two entry points must work
282 together in order to produce the correct output file.
284 The details of how this works are inevitably dependent upon
285 the specific object file format. The a.out
286 <<_bfd_final_link>> routine is <<NAME(aout,final_link)>>.
289 @* Information provided by the linker::
290 @* Relocating the section contents::
291 @* Writing the symbol table::
295 Information provided by the linker, Relocating the section contents, Performing the Final Link, Performing the Final Link
297 Information provided by the linker
299 Before the linker calls the <<_bfd_final_link>> entry point,
300 it sets up some data structures for the function to use.
302 The <<input_bfds>> field of the <<bfd_link_info>> structure
303 will point to a list of all the input files included in the
304 link. These files are linked through the <<link.next>> field
305 of the <<bfd>> structure.
307 Each section in the output file will have a list of
308 <<link_order>> structures attached to the <<map_head.link_order>>
309 field (the <<link_order>> structure is defined in
310 <<bfdlink.h>>). These structures describe how to create the
311 contents of the output section in terms of the contents of
312 various input sections, fill constants, and, eventually, other
313 types of information. They also describe relocs that must be
314 created by the BFD backend, but do not correspond to any input
315 file; this is used to support -Ur, which builds constructors
316 while generating a relocatable object file.
319 Relocating the section contents, Writing the symbol table, Information provided by the linker, Performing the Final Link
321 Relocating the section contents
323 The <<_bfd_final_link>> function should look through the
324 <<link_order>> structures attached to each section of the
325 output file. Each <<link_order>> structure should either be
326 handled specially, or it should be passed to the function
327 <<_bfd_default_link_order>> which will do the right thing
328 (<<_bfd_default_link_order>> is defined in <<linker.c>>).
330 For efficiency, a <<link_order>> of type
331 <<bfd_indirect_link_order>> whose associated section belongs
332 to a BFD of the same format as the output BFD must be handled
333 specially. This type of <<link_order>> describes part of an
334 output section in terms of a section belonging to one of the
335 input files. The <<_bfd_final_link>> function should read the
336 contents of the section and any associated relocs, apply the
337 relocs to the section contents, and write out the modified
338 section contents. If performing a relocatable link, the
339 relocs themselves must also be modified and written out.
341 @findex _bfd_relocate_contents
342 @findex _bfd_final_link_relocate
343 The functions <<_bfd_relocate_contents>> and
344 <<_bfd_final_link_relocate>> provide some general support for
345 performing the actual relocations, notably overflow checking.
346 Their arguments include information about the symbol the
347 relocation is against and a <<reloc_howto_type>> argument
348 which describes the relocation to perform. These functions
349 are defined in <<reloc.c>>.
351 The a.out function which handles reading, relocating, and
352 writing section contents is <<aout_link_input_section>>. The
353 actual relocation is done in <<aout_link_input_section_std>>
354 and <<aout_link_input_section_ext>>.
357 Writing the symbol table, , Relocating the section contents, Performing the Final Link
359 Writing the symbol table
361 The <<_bfd_final_link>> function must gather all the symbols
362 in the input files and write them out. It must also write out
363 all the symbols in the global hash table. This must be
364 controlled by the <<strip>> and <<discard>> fields of the
365 <<bfd_link_info>> structure.
367 The local symbols of the input files will not have been
368 entered into the linker hash table. The <<_bfd_final_link>>
369 routine must consider each input file and include the symbols
370 in the output file. It may be convenient to do this when
371 looking through the <<link_order>> structures, or it may be
372 done by stepping through the <<input_bfds>> list.
374 The <<_bfd_final_link>> routine must also traverse the global
375 hash table to gather all the externally visible symbols. It
376 is possible that most of the externally visible symbols may be
377 written out when considering the symbols of each input file,
378 but it is still necessary to traverse the hash table since the
379 linker script may have defined some symbols that are not in
380 any of the input files.
382 The <<strip>> field of the <<bfd_link_info>> structure
383 controls which symbols are written out. The possible values
384 are listed in <<bfdlink.h>>. If the value is <<strip_some>>,
385 then the <<keep_hash>> field of the <<bfd_link_info>>
386 structure is a hash table of symbols to keep; each symbol
387 should be looked up in this hash table, and only symbols which
388 are present should be included in the output file.
390 If the <<strip>> field of the <<bfd_link_info>> structure
391 permits local symbols to be written out, the <<discard>> field
392 is used to further controls which local symbols are included
393 in the output file. If the value is <<discard_l>>, then all
394 local symbols which begin with a certain prefix are discarded;
395 this is controlled by the <<bfd_is_local_label_name>> entry point.
397 The a.out backend handles symbols by calling
398 <<aout_link_write_symbols>> on each input BFD and then
399 traversing the global hash table with the function
400 <<aout_link_write_other_symbol>>. It builds a string table
401 while writing out the symbols, which is written to the output
402 file at the end of <<NAME(aout,final_link)>>.
405 static bfd_boolean generic_link_add_object_symbols
406 (bfd *, struct bfd_link_info *, bfd_boolean collect);
407 static bfd_boolean generic_link_add_symbols
408 (bfd *, struct bfd_link_info *, bfd_boolean);
409 static bfd_boolean generic_link_check_archive_element_no_collect
410 (bfd *, struct bfd_link_info *, struct bfd_link_hash_entry *, const char *,
412 static bfd_boolean generic_link_check_archive_element_collect
413 (bfd *, struct bfd_link_info *, struct bfd_link_hash_entry *, const char *,
415 static bfd_boolean generic_link_check_archive_element
416 (bfd *, struct bfd_link_info *, struct bfd_link_hash_entry *, const char *,
417 bfd_boolean *, bfd_boolean);
418 static bfd_boolean generic_link_add_symbol_list
419 (bfd *, struct bfd_link_info *, bfd_size_type count, asymbol **,
421 static bfd_boolean generic_add_output_symbol
422 (bfd *, size_t *psymalloc, asymbol *);
423 static bfd_boolean default_data_link_order
424 (bfd *, struct bfd_link_info *, asection *, struct bfd_link_order *);
425 static bfd_boolean default_indirect_link_order
426 (bfd *, struct bfd_link_info *, asection *, struct bfd_link_order *,
429 /* The link hash table structure is defined in bfdlink.h. It provides
430 a base hash table which the backend specific hash tables are built
433 /* Routine to create an entry in the link hash table. */
435 struct bfd_hash_entry *
436 _bfd_link_hash_newfunc (struct bfd_hash_entry *entry,
437 struct bfd_hash_table *table,
440 /* Allocate the structure if it has not already been allocated by a
444 entry = (struct bfd_hash_entry *)
445 bfd_hash_allocate (table, sizeof (struct bfd_link_hash_entry));
450 /* Call the allocation method of the superclass. */
451 entry = bfd_hash_newfunc (entry, table, string);
454 struct bfd_link_hash_entry *h = (struct bfd_link_hash_entry *) entry;
456 /* Initialize the local fields. */
457 memset ((char *) &h->root + sizeof (h->root), 0,
458 sizeof (*h) - sizeof (h->root));
464 /* Initialize a link hash table. The BFD argument is the one
465 responsible for creating this table. */
468 _bfd_link_hash_table_init
469 (struct bfd_link_hash_table *table,
470 bfd *abfd ATTRIBUTE_UNUSED,
471 struct bfd_hash_entry *(*newfunc) (struct bfd_hash_entry *,
472 struct bfd_hash_table *,
474 unsigned int entsize)
478 BFD_ASSERT (!abfd->is_linker_output && !abfd->link.hash);
479 table->undefs = NULL;
480 table->undefs_tail = NULL;
481 table->type = bfd_link_generic_hash_table;
483 ret = bfd_hash_table_init (&table->table, newfunc, entsize);
486 /* Arrange for destruction of this hash table on closing ABFD. */
487 table->hash_table_free = _bfd_generic_link_hash_table_free;
488 abfd->link.hash = table;
489 abfd->is_linker_output = TRUE;
494 /* Look up a symbol in a link hash table. If follow is TRUE, we
495 follow bfd_link_hash_indirect and bfd_link_hash_warning links to
498 struct bfd_link_hash_entry *
499 bfd_link_hash_lookup (struct bfd_link_hash_table *table,
505 struct bfd_link_hash_entry *ret;
507 ret = ((struct bfd_link_hash_entry *)
508 bfd_hash_lookup (&table->table, string, create, copy));
510 if (follow && ret != NULL)
512 while (ret->type == bfd_link_hash_indirect
513 || ret->type == bfd_link_hash_warning)
520 /* Look up a symbol in the main linker hash table if the symbol might
521 be wrapped. This should only be used for references to an
522 undefined symbol, not for definitions of a symbol. */
524 struct bfd_link_hash_entry *
525 bfd_wrapped_link_hash_lookup (bfd *abfd,
526 struct bfd_link_info *info,
534 if (info->wrap_hash != NULL)
540 if (*l == bfd_get_symbol_leading_char (abfd) || *l == info->wrap_char)
547 #define WRAP "__wrap_"
549 if (bfd_hash_lookup (info->wrap_hash, l, FALSE, FALSE) != NULL)
552 struct bfd_link_hash_entry *h;
554 /* This symbol is being wrapped. We want to replace all
555 references to SYM with references to __wrap_SYM. */
557 amt = strlen (l) + sizeof WRAP + 1;
558 n = (char *) bfd_malloc (amt);
566 h = bfd_link_hash_lookup (info->hash, n, create, TRUE, follow);
572 #define REAL "__real_"
575 && CONST_STRNEQ (l, REAL)
576 && bfd_hash_lookup (info->wrap_hash, l + sizeof REAL - 1,
577 FALSE, FALSE) != NULL)
580 struct bfd_link_hash_entry *h;
582 /* This is a reference to __real_SYM, where SYM is being
583 wrapped. We want to replace all references to __real_SYM
584 with references to SYM. */
586 amt = strlen (l + sizeof REAL - 1) + 2;
587 n = (char *) bfd_malloc (amt);
593 strcat (n, l + sizeof REAL - 1);
594 h = bfd_link_hash_lookup (info->hash, n, create, TRUE, follow);
602 return bfd_link_hash_lookup (info->hash, string, create, copy, follow);
605 /* If H is a wrapped symbol, ie. the symbol name starts with "__wrap_"
606 and the remainder is found in wrap_hash, return the real symbol. */
608 struct bfd_link_hash_entry *
609 unwrap_hash_lookup (struct bfd_link_info *info,
611 struct bfd_link_hash_entry *h)
613 const char *l = h->root.string;
615 if (*l == bfd_get_symbol_leading_char (input_bfd)
616 || *l == info->wrap_char)
619 if (CONST_STRNEQ (l, WRAP))
621 l += sizeof WRAP - 1;
623 if (bfd_hash_lookup (info->wrap_hash, l, FALSE, FALSE) != NULL)
626 if (l - (sizeof WRAP - 1) != h->root.string)
630 *(char *) l = *h->root.string;
632 h = bfd_link_hash_lookup (info->hash, l, FALSE, FALSE, FALSE);
641 /* Traverse a generic link hash table. Differs from bfd_hash_traverse
642 in the treatment of warning symbols. When warning symbols are
643 created they replace the real symbol, so you don't get to see the
644 real symbol in a bfd_hash_travere. This traversal calls func with
648 bfd_link_hash_traverse
649 (struct bfd_link_hash_table *htab,
650 bfd_boolean (*func) (struct bfd_link_hash_entry *, void *),
655 htab->table.frozen = 1;
656 for (i = 0; i < htab->table.size; i++)
658 struct bfd_link_hash_entry *p;
660 p = (struct bfd_link_hash_entry *) htab->table.table[i];
661 for (; p != NULL; p = (struct bfd_link_hash_entry *) p->root.next)
662 if (!(*func) (p->type == bfd_link_hash_warning ? p->u.i.link : p, info))
666 htab->table.frozen = 0;
669 /* Add a symbol to the linker hash table undefs list. */
672 bfd_link_add_undef (struct bfd_link_hash_table *table,
673 struct bfd_link_hash_entry *h)
675 BFD_ASSERT (h->u.undef.next == NULL);
676 if (table->undefs_tail != NULL)
677 table->undefs_tail->u.undef.next = h;
678 if (table->undefs == NULL)
680 table->undefs_tail = h;
683 /* The undefs list was designed so that in normal use we don't need to
684 remove entries. However, if symbols on the list are changed from
685 bfd_link_hash_undefined to either bfd_link_hash_undefweak or
686 bfd_link_hash_new for some reason, then they must be removed from the
687 list. Failure to do so might result in the linker attempting to add
688 the symbol to the list again at a later stage. */
691 bfd_link_repair_undef_list (struct bfd_link_hash_table *table)
693 struct bfd_link_hash_entry **pun;
695 pun = &table->undefs;
698 struct bfd_link_hash_entry *h = *pun;
700 if (h->type == bfd_link_hash_new
701 || h->type == bfd_link_hash_undefweak)
703 *pun = h->u.undef.next;
704 h->u.undef.next = NULL;
705 if (h == table->undefs_tail)
707 if (pun == &table->undefs)
708 table->undefs_tail = NULL;
710 /* pun points at an u.undef.next field. Go back to
711 the start of the link_hash_entry. */
712 table->undefs_tail = (struct bfd_link_hash_entry *)
713 ((char *) pun - ((char *) &h->u.undef.next - (char *) h));
718 pun = &h->u.undef.next;
722 /* Routine to create an entry in a generic link hash table. */
724 struct bfd_hash_entry *
725 _bfd_generic_link_hash_newfunc (struct bfd_hash_entry *entry,
726 struct bfd_hash_table *table,
729 /* Allocate the structure if it has not already been allocated by a
733 entry = (struct bfd_hash_entry *)
734 bfd_hash_allocate (table, sizeof (struct generic_link_hash_entry));
739 /* Call the allocation method of the superclass. */
740 entry = _bfd_link_hash_newfunc (entry, table, string);
743 struct generic_link_hash_entry *ret;
745 /* Set local fields. */
746 ret = (struct generic_link_hash_entry *) entry;
747 ret->written = FALSE;
754 /* Create a generic link hash table. */
756 struct bfd_link_hash_table *
757 _bfd_generic_link_hash_table_create (bfd *abfd)
759 struct generic_link_hash_table *ret;
760 bfd_size_type amt = sizeof (struct generic_link_hash_table);
762 ret = (struct generic_link_hash_table *) bfd_malloc (amt);
765 if (! _bfd_link_hash_table_init (&ret->root, abfd,
766 _bfd_generic_link_hash_newfunc,
767 sizeof (struct generic_link_hash_entry)))
776 _bfd_generic_link_hash_table_free (bfd *obfd)
778 struct generic_link_hash_table *ret;
780 BFD_ASSERT (obfd->is_linker_output && obfd->link.hash);
781 ret = (struct generic_link_hash_table *) obfd->link.hash;
782 bfd_hash_table_free (&ret->root.table);
784 obfd->link.hash = NULL;
785 obfd->is_linker_output = FALSE;
788 /* Grab the symbols for an object file when doing a generic link. We
789 store the symbols in the outsymbols field. We need to keep them
790 around for the entire link to ensure that we only read them once.
791 If we read them multiple times, we might wind up with relocs and
792 the hash table pointing to different instances of the symbol
796 bfd_generic_link_read_symbols (bfd *abfd)
798 if (bfd_get_outsymbols (abfd) == NULL)
803 symsize = bfd_get_symtab_upper_bound (abfd);
806 bfd_get_outsymbols (abfd) = (struct bfd_symbol **) bfd_alloc (abfd,
808 if (bfd_get_outsymbols (abfd) == NULL && symsize != 0)
810 symcount = bfd_canonicalize_symtab (abfd, bfd_get_outsymbols (abfd));
813 bfd_get_symcount (abfd) = symcount;
819 /* Generic function to add symbols to from an object file to the
820 global hash table. This version does not automatically collect
821 constructors by name. */
824 _bfd_generic_link_add_symbols (bfd *abfd, struct bfd_link_info *info)
826 return generic_link_add_symbols (abfd, info, FALSE);
829 /* Generic function to add symbols from an object file to the global
830 hash table. This version automatically collects constructors by
831 name, as the collect2 program does. It should be used for any
832 target which does not provide some other mechanism for setting up
833 constructors and destructors; these are approximately those targets
834 for which gcc uses collect2 and do not support stabs. */
837 _bfd_generic_link_add_symbols_collect (bfd *abfd, struct bfd_link_info *info)
839 return generic_link_add_symbols (abfd, info, TRUE);
842 /* Indicate that we are only retrieving symbol values from this
843 section. We want the symbols to act as though the values in the
844 file are absolute. */
847 _bfd_generic_link_just_syms (asection *sec,
848 struct bfd_link_info *info ATTRIBUTE_UNUSED)
850 sec->sec_info_type = SEC_INFO_TYPE_JUST_SYMS;
851 sec->output_section = bfd_abs_section_ptr;
852 sec->output_offset = sec->vma;
855 /* Copy the symbol type and other attributes for a linker script
856 assignment from HSRC to HDEST.
857 The default implementation does nothing. */
859 _bfd_generic_copy_link_hash_symbol_type (bfd *abfd ATTRIBUTE_UNUSED,
860 struct bfd_link_hash_entry *hdest ATTRIBUTE_UNUSED,
861 struct bfd_link_hash_entry *hsrc ATTRIBUTE_UNUSED)
865 /* Add symbols from an object file to the global hash table. */
868 generic_link_add_symbols (bfd *abfd,
869 struct bfd_link_info *info,
874 switch (bfd_get_format (abfd))
877 ret = generic_link_add_object_symbols (abfd, info, collect);
880 ret = (_bfd_generic_link_add_archive_symbols
883 ? generic_link_check_archive_element_collect
884 : generic_link_check_archive_element_no_collect)));
887 bfd_set_error (bfd_error_wrong_format);
894 /* Add symbols from an object file to the global hash table. */
897 generic_link_add_object_symbols (bfd *abfd,
898 struct bfd_link_info *info,
901 bfd_size_type symcount;
902 struct bfd_symbol **outsyms;
904 if (!bfd_generic_link_read_symbols (abfd))
906 symcount = _bfd_generic_link_get_symcount (abfd);
907 outsyms = _bfd_generic_link_get_symbols (abfd);
908 return generic_link_add_symbol_list (abfd, info, symcount, outsyms, collect);
911 /* Generic function to add symbols from an archive file to the global
912 hash file. This function presumes that the archive symbol table
913 has already been read in (this is normally done by the
914 bfd_check_format entry point). It looks through the archive symbol
915 table for symbols that are undefined or common in the linker global
916 symbol hash table. When one is found, the CHECKFN argument is used
917 to see if an object file should be included. This allows targets
918 to customize common symbol behaviour. CHECKFN should set *PNEEDED
919 to TRUE if the object file should be included, and must also call
920 the bfd_link_info add_archive_element callback function and handle
921 adding the symbols to the global hash table. CHECKFN must notice
922 if the callback indicates a substitute BFD, and arrange to add
923 those symbols instead if it does so. CHECKFN should only return
924 FALSE if some sort of error occurs. */
927 _bfd_generic_link_add_archive_symbols
929 struct bfd_link_info *info,
930 bfd_boolean (*checkfn) (bfd *, struct bfd_link_info *,
931 struct bfd_link_hash_entry *, const char *,
936 unsigned char *included;
938 if (! bfd_has_map (abfd))
940 /* An empty archive is a special case. */
941 if (bfd_openr_next_archived_file (abfd, NULL) == NULL)
943 bfd_set_error (bfd_error_no_armap);
947 amt = bfd_ardata (abfd)->symdef_count;
950 amt *= sizeof (*included);
951 included = (unsigned char *) bfd_zmalloc (amt);
952 if (included == NULL)
961 file_ptr last_ar_offset = -1;
962 bfd_boolean needed = FALSE;
966 arsyms = bfd_ardata (abfd)->symdefs;
967 arsym_end = arsyms + bfd_ardata (abfd)->symdef_count;
968 for (arsym = arsyms, indx = 0; arsym < arsym_end; arsym++, indx++)
970 struct bfd_link_hash_entry *h;
971 struct bfd_link_hash_entry *undefs_tail;
975 if (needed && arsym->file_offset == last_ar_offset)
981 h = bfd_link_hash_lookup (info->hash, arsym->name,
985 && info->pei386_auto_import
986 && CONST_STRNEQ (arsym->name, "__imp_"))
987 h = bfd_link_hash_lookup (info->hash, arsym->name + 6,
992 if (h->type != bfd_link_hash_undefined
993 && h->type != bfd_link_hash_common)
995 if (h->type != bfd_link_hash_undefweak)
996 /* Symbol must be defined. Don't check it again. */
1001 if (last_ar_offset != arsym->file_offset)
1003 last_ar_offset = arsym->file_offset;
1004 element = _bfd_get_elt_at_filepos (abfd, last_ar_offset);
1006 || !bfd_check_format (element, bfd_object))
1010 undefs_tail = info->hash->undefs_tail;
1012 /* CHECKFN will see if this element should be included, and
1013 go ahead and include it if appropriate. */
1014 if (! (*checkfn) (element, info, h, arsym->name, &needed))
1021 /* Look backward to mark all symbols from this object file
1022 which we have already seen in this pass. */
1031 while (arsyms[mark].file_offset == last_ar_offset);
1033 if (undefs_tail != info->hash->undefs_tail)
1047 /* See if we should include an archive element. This version is used
1048 when we do not want to automatically collect constructors based on
1049 the symbol name, presumably because we have some other mechanism
1050 for finding them. */
1053 generic_link_check_archive_element_no_collect (bfd *abfd,
1054 struct bfd_link_info *info,
1055 struct bfd_link_hash_entry *h,
1057 bfd_boolean *pneeded)
1059 return generic_link_check_archive_element (abfd, info, h, name, pneeded,
1063 /* See if we should include an archive element. This version is used
1064 when we want to automatically collect constructors based on the
1065 symbol name, as collect2 does. */
1068 generic_link_check_archive_element_collect (bfd *abfd,
1069 struct bfd_link_info *info,
1070 struct bfd_link_hash_entry *h,
1072 bfd_boolean *pneeded)
1074 return generic_link_check_archive_element (abfd, info, h, name, pneeded,
1078 /* See if we should include an archive element. Optionally collect
1082 generic_link_check_archive_element (bfd *abfd,
1083 struct bfd_link_info *info,
1084 struct bfd_link_hash_entry *h,
1085 const char *name ATTRIBUTE_UNUSED,
1086 bfd_boolean *pneeded,
1087 bfd_boolean collect)
1089 asymbol **pp, **ppend;
1093 if (!bfd_generic_link_read_symbols (abfd))
1096 pp = _bfd_generic_link_get_symbols (abfd);
1097 ppend = pp + _bfd_generic_link_get_symcount (abfd);
1098 for (; pp < ppend; pp++)
1104 /* We are only interested in globally visible symbols. */
1105 if (! bfd_is_com_section (p->section)
1106 && (p->flags & (BSF_GLOBAL | BSF_INDIRECT | BSF_WEAK)) == 0)
1109 /* We are only interested if we know something about this
1110 symbol, and it is undefined or common. An undefined weak
1111 symbol (type bfd_link_hash_undefweak) is not considered to be
1112 a reference when pulling files out of an archive. See the
1113 SVR4 ABI, p. 4-27. */
1114 h = bfd_link_hash_lookup (info->hash, bfd_asymbol_name (p), FALSE,
1117 || (h->type != bfd_link_hash_undefined
1118 && h->type != bfd_link_hash_common))
1121 /* P is a symbol we are looking for. */
1123 if (! bfd_is_com_section (p->section))
1125 bfd_size_type symcount;
1129 /* This object file defines this symbol, so pull it in. */
1130 if (!(*info->callbacks
1131 ->add_archive_element) (info, abfd, bfd_asymbol_name (p),
1134 /* Potentially, the add_archive_element hook may have set a
1135 substitute BFD for us. */
1137 && !bfd_generic_link_read_symbols (abfd))
1139 symcount = _bfd_generic_link_get_symcount (abfd);
1140 symbols = _bfd_generic_link_get_symbols (abfd);
1141 if (! generic_link_add_symbol_list (abfd, info, symcount,
1148 /* P is a common symbol. */
1150 if (h->type == bfd_link_hash_undefined)
1156 symbfd = h->u.undef.abfd;
1159 /* This symbol was created as undefined from outside
1160 BFD. We assume that we should link in the object
1161 file. This is for the -u option in the linker. */
1162 if (!(*info->callbacks
1163 ->add_archive_element) (info, abfd, bfd_asymbol_name (p),
1166 /* Potentially, the add_archive_element hook may have set a
1167 substitute BFD for us. But no symbols are going to get
1168 registered by anything we're returning to from here. */
1173 /* Turn the symbol into a common symbol but do not link in
1174 the object file. This is how a.out works. Object
1175 formats that require different semantics must implement
1176 this function differently. This symbol is already on the
1177 undefs list. We add the section to a common section
1178 attached to symbfd to ensure that it is in a BFD which
1179 will be linked in. */
1180 h->type = bfd_link_hash_common;
1181 h->u.c.p = (struct bfd_link_hash_common_entry *)
1182 bfd_hash_allocate (&info->hash->table,
1183 sizeof (struct bfd_link_hash_common_entry));
1184 if (h->u.c.p == NULL)
1187 size = bfd_asymbol_value (p);
1190 power = bfd_log2 (size);
1193 h->u.c.p->alignment_power = power;
1195 if (p->section == bfd_com_section_ptr)
1196 h->u.c.p->section = bfd_make_section_old_way (symbfd, "COMMON");
1198 h->u.c.p->section = bfd_make_section_old_way (symbfd,
1200 h->u.c.p->section->flags |= SEC_ALLOC;
1204 /* Adjust the size of the common symbol if necessary. This
1205 is how a.out works. Object formats that require
1206 different semantics must implement this function
1208 if (bfd_asymbol_value (p) > h->u.c.size)
1209 h->u.c.size = bfd_asymbol_value (p);
1213 /* This archive element is not needed. */
1217 /* Add the symbols from an object file to the global hash table. ABFD
1218 is the object file. INFO is the linker information. SYMBOL_COUNT
1219 is the number of symbols. SYMBOLS is the list of symbols. COLLECT
1220 is TRUE if constructors should be automatically collected by name
1221 as is done by collect2. */
1224 generic_link_add_symbol_list (bfd *abfd,
1225 struct bfd_link_info *info,
1226 bfd_size_type symbol_count,
1228 bfd_boolean collect)
1230 asymbol **pp, **ppend;
1233 ppend = symbols + symbol_count;
1234 for (; pp < ppend; pp++)
1240 if ((p->flags & (BSF_INDIRECT
1245 || bfd_is_und_section (bfd_get_section (p))
1246 || bfd_is_com_section (bfd_get_section (p))
1247 || bfd_is_ind_section (bfd_get_section (p)))
1251 struct generic_link_hash_entry *h;
1252 struct bfd_link_hash_entry *bh;
1254 string = name = bfd_asymbol_name (p);
1255 if (((p->flags & BSF_INDIRECT) != 0
1256 || bfd_is_ind_section (p->section))
1260 string = bfd_asymbol_name (*pp);
1262 else if ((p->flags & BSF_WARNING) != 0
1265 /* The name of P is actually the warning string, and the
1266 next symbol is the one to warn about. */
1268 name = bfd_asymbol_name (*pp);
1272 if (! (_bfd_generic_link_add_one_symbol
1273 (info, abfd, name, p->flags, bfd_get_section (p),
1274 p->value, string, FALSE, collect, &bh)))
1276 h = (struct generic_link_hash_entry *) bh;
1278 /* If this is a constructor symbol, and the linker didn't do
1279 anything with it, then we want to just pass the symbol
1280 through to the output file. This will happen when
1282 if ((p->flags & BSF_CONSTRUCTOR) != 0
1283 && (h == NULL || h->root.type == bfd_link_hash_new))
1289 /* Save the BFD symbol so that we don't lose any backend
1290 specific information that may be attached to it. We only
1291 want this one if it gives more information than the
1292 existing one; we don't want to replace a defined symbol
1293 with an undefined one. This routine may be called with a
1294 hash table other than the generic hash table, so we only
1295 do this if we are certain that the hash table is a
1297 if (info->output_bfd->xvec == abfd->xvec)
1300 || (! bfd_is_und_section (bfd_get_section (p))
1301 && (! bfd_is_com_section (bfd_get_section (p))
1302 || bfd_is_und_section (bfd_get_section (h->sym)))))
1305 /* BSF_OLD_COMMON is a hack to support COFF reloc
1306 reading, and it should go away when the COFF
1307 linker is switched to the new version. */
1308 if (bfd_is_com_section (bfd_get_section (p)))
1309 p->flags |= BSF_OLD_COMMON;
1313 /* Store a back pointer from the symbol to the hash
1314 table entry for the benefit of relaxation code until
1315 it gets rewritten to not use asymbol structures.
1316 Setting this is also used to check whether these
1317 symbols were set up by the generic linker. */
1325 /* We use a state table to deal with adding symbols from an object
1326 file. The first index into the state table describes the symbol
1327 from the object file. The second index into the state table is the
1328 type of the symbol in the hash table. */
1330 /* The symbol from the object file is turned into one of these row
1335 UNDEF_ROW, /* Undefined. */
1336 UNDEFW_ROW, /* Weak undefined. */
1337 DEF_ROW, /* Defined. */
1338 DEFW_ROW, /* Weak defined. */
1339 COMMON_ROW, /* Common. */
1340 INDR_ROW, /* Indirect. */
1341 WARN_ROW, /* Warning. */
1342 SET_ROW /* Member of set. */
1345 /* apparently needed for Hitachi 3050R(HI-UX/WE2)? */
1348 /* The actions to take in the state table. */
1353 UND, /* Mark symbol undefined. */
1354 WEAK, /* Mark symbol weak undefined. */
1355 DEF, /* Mark symbol defined. */
1356 DEFW, /* Mark symbol weak defined. */
1357 COM, /* Mark symbol common. */
1358 REF, /* Mark defined symbol referenced. */
1359 CREF, /* Possibly warn about common reference to defined symbol. */
1360 CDEF, /* Define existing common symbol. */
1361 NOACT, /* No action. */
1362 BIG, /* Mark symbol common using largest size. */
1363 MDEF, /* Multiple definition error. */
1364 MIND, /* Multiple indirect symbols. */
1365 IND, /* Make indirect symbol. */
1366 CIND, /* Make indirect symbol from existing common symbol. */
1367 SET, /* Add value to set. */
1368 MWARN, /* Make warning symbol. */
1369 WARN, /* Issue warning. */
1370 CWARN, /* Warn if referenced, else MWARN. */
1371 CYCLE, /* Repeat with symbol pointed to. */
1372 REFC, /* Mark indirect symbol referenced and then CYCLE. */
1373 WARNC /* Issue warning and then CYCLE. */
1376 /* The state table itself. The first index is a link_row and the
1377 second index is a bfd_link_hash_type. */
1379 static const enum link_action link_action[8][8] =
1381 /* current\prev new undef undefw def defw com indr warn */
1382 /* UNDEF_ROW */ {UND, NOACT, UND, REF, REF, NOACT, REFC, WARNC },
1383 /* UNDEFW_ROW */ {WEAK, NOACT, NOACT, REF, REF, NOACT, REFC, WARNC },
1384 /* DEF_ROW */ {DEF, DEF, DEF, MDEF, DEF, CDEF, MDEF, CYCLE },
1385 /* DEFW_ROW */ {DEFW, DEFW, DEFW, NOACT, NOACT, NOACT, NOACT, CYCLE },
1386 /* COMMON_ROW */ {COM, COM, COM, CREF, COM, BIG, REFC, WARNC },
1387 /* INDR_ROW */ {IND, IND, IND, MDEF, IND, CIND, MIND, CYCLE },
1388 /* WARN_ROW */ {MWARN, WARN, WARN, CWARN, CWARN, WARN, CWARN, NOACT },
1389 /* SET_ROW */ {SET, SET, SET, SET, SET, SET, CYCLE, CYCLE }
1392 /* Most of the entries in the LINK_ACTION table are straightforward,
1393 but a few are somewhat subtle.
1395 A reference to an indirect symbol (UNDEF_ROW/indr or
1396 UNDEFW_ROW/indr) is counted as a reference both to the indirect
1397 symbol and to the symbol the indirect symbol points to.
1399 A reference to a warning symbol (UNDEF_ROW/warn or UNDEFW_ROW/warn)
1400 causes the warning to be issued.
1402 A common definition of an indirect symbol (COMMON_ROW/indr) is
1403 treated as a multiple definition error. Likewise for an indirect
1404 definition of a common symbol (INDR_ROW/com).
1406 An indirect definition of a warning (INDR_ROW/warn) does not cause
1407 the warning to be issued.
1409 If a warning is created for an indirect symbol (WARN_ROW/indr) no
1410 warning is created for the symbol the indirect symbol points to.
1412 Adding an entry to a set does not count as a reference to a set,
1413 and no warning is issued (SET_ROW/warn). */
1415 /* Return the BFD in which a hash entry has been defined, if known. */
1418 hash_entry_bfd (struct bfd_link_hash_entry *h)
1420 while (h->type == bfd_link_hash_warning)
1426 case bfd_link_hash_undefined:
1427 case bfd_link_hash_undefweak:
1428 return h->u.undef.abfd;
1429 case bfd_link_hash_defined:
1430 case bfd_link_hash_defweak:
1431 return h->u.def.section->owner;
1432 case bfd_link_hash_common:
1433 return h->u.c.p->section->owner;
1438 /* Add a symbol to the global hash table.
1439 ABFD is the BFD the symbol comes from.
1440 NAME is the name of the symbol.
1441 FLAGS is the BSF_* bits associated with the symbol.
1442 SECTION is the section in which the symbol is defined; this may be
1443 bfd_und_section_ptr or bfd_com_section_ptr.
1444 VALUE is the value of the symbol, relative to the section.
1445 STRING is used for either an indirect symbol, in which case it is
1446 the name of the symbol to indirect to, or a warning symbol, in
1447 which case it is the warning string.
1448 COPY is TRUE if NAME or STRING must be copied into locally
1449 allocated memory if they need to be saved.
1450 COLLECT is TRUE if we should automatically collect gcc constructor
1451 or destructor names as collect2 does.
1452 HASHP, if not NULL, is a place to store the created hash table
1453 entry; if *HASHP is not NULL, the caller has already looked up
1454 the hash table entry, and stored it in *HASHP. */
1457 _bfd_generic_link_add_one_symbol (struct bfd_link_info *info,
1465 bfd_boolean collect,
1466 struct bfd_link_hash_entry **hashp)
1469 struct bfd_link_hash_entry *h;
1472 BFD_ASSERT (section != NULL);
1474 if (bfd_is_ind_section (section)
1475 || (flags & BSF_INDIRECT) != 0)
1477 else if ((flags & BSF_WARNING) != 0)
1479 else if ((flags & BSF_CONSTRUCTOR) != 0)
1481 else if (bfd_is_und_section (section))
1483 if ((flags & BSF_WEAK) != 0)
1488 else if ((flags & BSF_WEAK) != 0)
1490 else if (bfd_is_com_section (section))
1493 if (strcmp (name, "__gnu_lto_slim") == 0)
1494 (*_bfd_error_handler)
1495 (_("%s: plugin needed to handle lto object"),
1496 bfd_get_filename (abfd));
1501 if (hashp != NULL && *hashp != NULL)
1505 if (row == UNDEF_ROW || row == UNDEFW_ROW)
1506 h = bfd_wrapped_link_hash_lookup (abfd, info, name, TRUE, copy, FALSE);
1508 h = bfd_link_hash_lookup (info->hash, name, TRUE, copy, FALSE);
1517 if (info->notice_all
1518 || (info->notice_hash != NULL
1519 && bfd_hash_lookup (info->notice_hash, name, FALSE, FALSE) != NULL))
1521 if (! (*info->callbacks->notice) (info, h,
1522 abfd, section, value, flags, string))
1531 enum link_action action;
1534 action = link_action[(int) row][(int) h->type];
1545 /* Make a new undefined symbol. */
1546 h->type = bfd_link_hash_undefined;
1547 h->u.undef.abfd = abfd;
1548 bfd_link_add_undef (info->hash, h);
1552 /* Make a new weak undefined symbol. */
1553 h->type = bfd_link_hash_undefweak;
1554 h->u.undef.abfd = abfd;
1558 /* We have found a definition for a symbol which was
1559 previously common. */
1560 BFD_ASSERT (h->type == bfd_link_hash_common);
1561 if (! ((*info->callbacks->multiple_common)
1562 (info, h, abfd, bfd_link_hash_defined, 0)))
1568 enum bfd_link_hash_type oldtype;
1570 /* Define a symbol. */
1573 h->type = bfd_link_hash_defweak;
1575 h->type = bfd_link_hash_defined;
1576 h->u.def.section = section;
1577 h->u.def.value = value;
1579 /* If we have been asked to, we act like collect2 and
1580 identify all functions that might be global
1581 constructors and destructors and pass them up in a
1582 callback. We only do this for certain object file
1583 types, since many object file types can handle this
1585 if (collect && name[0] == '_')
1589 /* A constructor or destructor name starts like this:
1590 _+GLOBAL_[_.$][ID][_.$] where the first [_.$] and
1591 the second are the same character (we accept any
1592 character there, in case a new object file format
1593 comes along with even worse naming restrictions). */
1595 #define CONS_PREFIX "GLOBAL_"
1596 #define CONS_PREFIX_LEN (sizeof CONS_PREFIX - 1)
1601 if (s[0] == 'G' && CONST_STRNEQ (s, CONS_PREFIX))
1605 c = s[CONS_PREFIX_LEN + 1];
1606 if ((c == 'I' || c == 'D')
1607 && s[CONS_PREFIX_LEN] == s[CONS_PREFIX_LEN + 2])
1609 /* If this is a definition of a symbol which
1610 was previously weakly defined, we are in
1611 trouble. We have already added a
1612 constructor entry for the weak defined
1613 symbol, and now we are trying to add one
1614 for the new symbol. Fortunately, this case
1615 should never arise in practice. */
1616 if (oldtype == bfd_link_hash_defweak)
1619 if (! ((*info->callbacks->constructor)
1621 h->root.string, abfd, section, value)))
1631 /* We have found a common definition for a symbol. */
1632 if (h->type == bfd_link_hash_new)
1633 bfd_link_add_undef (info->hash, h);
1634 h->type = bfd_link_hash_common;
1635 h->u.c.p = (struct bfd_link_hash_common_entry *)
1636 bfd_hash_allocate (&info->hash->table,
1637 sizeof (struct bfd_link_hash_common_entry));
1638 if (h->u.c.p == NULL)
1641 h->u.c.size = value;
1643 /* Select a default alignment based on the size. This may
1644 be overridden by the caller. */
1648 power = bfd_log2 (value);
1651 h->u.c.p->alignment_power = power;
1654 /* The section of a common symbol is only used if the common
1655 symbol is actually allocated. It basically provides a
1656 hook for the linker script to decide which output section
1657 the common symbols should be put in. In most cases, the
1658 section of a common symbol will be bfd_com_section_ptr,
1659 the code here will choose a common symbol section named
1660 "COMMON", and the linker script will contain *(COMMON) in
1661 the appropriate place. A few targets use separate common
1662 sections for small symbols, and they require special
1664 if (section == bfd_com_section_ptr)
1666 h->u.c.p->section = bfd_make_section_old_way (abfd, "COMMON");
1667 h->u.c.p->section->flags |= SEC_ALLOC;
1669 else if (section->owner != abfd)
1671 h->u.c.p->section = bfd_make_section_old_way (abfd,
1673 h->u.c.p->section->flags |= SEC_ALLOC;
1676 h->u.c.p->section = section;
1680 /* A reference to a defined symbol. */
1681 if (h->u.undef.next == NULL && info->hash->undefs_tail != h)
1682 h->u.undef.next = h;
1686 /* We have found a common definition for a symbol which
1687 already had a common definition. Use the maximum of the
1688 two sizes, and use the section required by the larger symbol. */
1689 BFD_ASSERT (h->type == bfd_link_hash_common);
1690 if (! ((*info->callbacks->multiple_common)
1691 (info, h, abfd, bfd_link_hash_common, value)))
1693 if (value > h->u.c.size)
1697 h->u.c.size = value;
1699 /* Select a default alignment based on the size. This may
1700 be overridden by the caller. */
1701 power = bfd_log2 (value);
1704 h->u.c.p->alignment_power = power;
1706 /* Some systems have special treatment for small commons,
1707 hence we want to select the section used by the larger
1708 symbol. This makes sure the symbol does not go in a
1709 small common section if it is now too large. */
1710 if (section == bfd_com_section_ptr)
1713 = bfd_make_section_old_way (abfd, "COMMON");
1714 h->u.c.p->section->flags |= SEC_ALLOC;
1716 else if (section->owner != abfd)
1719 = bfd_make_section_old_way (abfd, section->name);
1720 h->u.c.p->section->flags |= SEC_ALLOC;
1723 h->u.c.p->section = section;
1728 /* We have found a common definition for a symbol which
1729 was already defined. */
1730 if (! ((*info->callbacks->multiple_common)
1731 (info, h, abfd, bfd_link_hash_common, value)))
1736 /* Multiple indirect symbols. This is OK if they both point
1737 to the same symbol. */
1738 if (strcmp (h->u.i.link->root.string, string) == 0)
1742 /* Handle a multiple definition. */
1743 if (! ((*info->callbacks->multiple_definition)
1744 (info, h, abfd, section, value)))
1749 /* Create an indirect symbol from an existing common symbol. */
1750 BFD_ASSERT (h->type == bfd_link_hash_common);
1751 if (! ((*info->callbacks->multiple_common)
1752 (info, h, abfd, bfd_link_hash_indirect, 0)))
1756 /* Create an indirect symbol. */
1758 struct bfd_link_hash_entry *inh;
1760 /* STRING is the name of the symbol we want to indirect
1762 inh = bfd_wrapped_link_hash_lookup (abfd, info, string, TRUE,
1766 if (inh->type == bfd_link_hash_indirect
1767 && inh->u.i.link == h)
1769 (*_bfd_error_handler)
1770 (_("%B: indirect symbol `%s' to `%s' is a loop"),
1771 abfd, name, string);
1772 bfd_set_error (bfd_error_invalid_operation);
1775 if (inh->type == bfd_link_hash_new)
1777 inh->type = bfd_link_hash_undefined;
1778 inh->u.undef.abfd = abfd;
1779 bfd_link_add_undef (info->hash, inh);
1782 /* If the indirect symbol has been referenced, we need to
1783 push the reference down to the symbol we are
1785 if (h->type != bfd_link_hash_new)
1791 h->type = bfd_link_hash_indirect;
1797 /* Add an entry to a set. */
1798 if (! (*info->callbacks->add_to_set) (info, h, BFD_RELOC_CTOR,
1799 abfd, section, value))
1804 /* Issue a warning and cycle. */
1805 if (h->u.i.warning != NULL)
1807 if (! (*info->callbacks->warning) (info, h->u.i.warning,
1808 h->root.string, abfd,
1811 /* Only issue a warning once. */
1812 h->u.i.warning = NULL;
1816 /* Try again with the referenced symbol. */
1822 /* A reference to an indirect symbol. */
1823 if (h->u.undef.next == NULL && info->hash->undefs_tail != h)
1824 h->u.undef.next = h;
1830 /* Issue a warning. */
1831 if (! (*info->callbacks->warning) (info, string, h->root.string,
1832 hash_entry_bfd (h), NULL, 0))
1837 /* Warn if this symbol has been referenced already,
1838 otherwise add a warning. A symbol has been referenced if
1839 the u.undef.next field is not NULL, or it is the tail of the
1840 undefined symbol list. The REF case above helps to
1842 if (h->u.undef.next != NULL || info->hash->undefs_tail == h)
1844 if (! (*info->callbacks->warning) (info, string, h->root.string,
1845 hash_entry_bfd (h), NULL, 0))
1851 /* Make a warning symbol. */
1853 struct bfd_link_hash_entry *sub;
1855 /* STRING is the warning to give. */
1856 sub = ((struct bfd_link_hash_entry *)
1857 ((*info->hash->table.newfunc)
1858 (NULL, &info->hash->table, h->root.string)));
1862 sub->type = bfd_link_hash_warning;
1865 sub->u.i.warning = string;
1869 size_t len = strlen (string) + 1;
1871 w = (char *) bfd_hash_allocate (&info->hash->table, len);
1874 memcpy (w, string, len);
1875 sub->u.i.warning = w;
1878 bfd_hash_replace (&info->hash->table,
1879 (struct bfd_hash_entry *) h,
1880 (struct bfd_hash_entry *) sub);
1892 /* Generic final link routine. */
1895 _bfd_generic_final_link (bfd *abfd, struct bfd_link_info *info)
1899 struct bfd_link_order *p;
1901 struct generic_write_global_symbol_info wginfo;
1903 bfd_get_outsymbols (abfd) = NULL;
1904 bfd_get_symcount (abfd) = 0;
1907 /* Mark all sections which will be included in the output file. */
1908 for (o = abfd->sections; o != NULL; o = o->next)
1909 for (p = o->map_head.link_order; p != NULL; p = p->next)
1910 if (p->type == bfd_indirect_link_order)
1911 p->u.indirect.section->linker_mark = TRUE;
1913 /* Build the output symbol table. */
1914 for (sub = info->input_bfds; sub != NULL; sub = sub->link.next)
1915 if (! _bfd_generic_link_output_symbols (abfd, sub, info, &outsymalloc))
1918 /* Accumulate the global symbols. */
1920 wginfo.output_bfd = abfd;
1921 wginfo.psymalloc = &outsymalloc;
1922 _bfd_generic_link_hash_traverse (_bfd_generic_hash_table (info),
1923 _bfd_generic_link_write_global_symbol,
1926 /* Make sure we have a trailing NULL pointer on OUTSYMBOLS. We
1927 shouldn't really need one, since we have SYMCOUNT, but some old
1928 code still expects one. */
1929 if (! generic_add_output_symbol (abfd, &outsymalloc, NULL))
1932 if (info->relocatable)
1934 /* Allocate space for the output relocs for each section. */
1935 for (o = abfd->sections; o != NULL; o = o->next)
1938 for (p = o->map_head.link_order; p != NULL; p = p->next)
1940 if (p->type == bfd_section_reloc_link_order
1941 || p->type == bfd_symbol_reloc_link_order)
1943 else if (p->type == bfd_indirect_link_order)
1945 asection *input_section;
1952 input_section = p->u.indirect.section;
1953 input_bfd = input_section->owner;
1954 relsize = bfd_get_reloc_upper_bound (input_bfd,
1958 relocs = (arelent **) bfd_malloc (relsize);
1959 if (!relocs && relsize != 0)
1961 symbols = _bfd_generic_link_get_symbols (input_bfd);
1962 reloc_count = bfd_canonicalize_reloc (input_bfd,
1967 if (reloc_count < 0)
1969 BFD_ASSERT ((unsigned long) reloc_count
1970 == input_section->reloc_count);
1971 o->reloc_count += reloc_count;
1974 if (o->reloc_count > 0)
1978 amt = o->reloc_count;
1979 amt *= sizeof (arelent *);
1980 o->orelocation = (struct reloc_cache_entry **) bfd_alloc (abfd, amt);
1981 if (!o->orelocation)
1983 o->flags |= SEC_RELOC;
1984 /* Reset the count so that it can be used as an index
1985 when putting in the output relocs. */
1991 /* Handle all the link order information for the sections. */
1992 for (o = abfd->sections; o != NULL; o = o->next)
1994 for (p = o->map_head.link_order; p != NULL; p = p->next)
1998 case bfd_section_reloc_link_order:
1999 case bfd_symbol_reloc_link_order:
2000 if (! _bfd_generic_reloc_link_order (abfd, info, o, p))
2003 case bfd_indirect_link_order:
2004 if (! default_indirect_link_order (abfd, info, o, p, TRUE))
2008 if (! _bfd_default_link_order (abfd, info, o, p))
2018 /* Add an output symbol to the output BFD. */
2021 generic_add_output_symbol (bfd *output_bfd, size_t *psymalloc, asymbol *sym)
2023 if (bfd_get_symcount (output_bfd) >= *psymalloc)
2028 if (*psymalloc == 0)
2033 amt *= sizeof (asymbol *);
2034 newsyms = (asymbol **) bfd_realloc (bfd_get_outsymbols (output_bfd), amt);
2035 if (newsyms == NULL)
2037 bfd_get_outsymbols (output_bfd) = newsyms;
2040 bfd_get_outsymbols (output_bfd) [bfd_get_symcount (output_bfd)] = sym;
2042 ++ bfd_get_symcount (output_bfd);
2047 /* Handle the symbols for an input BFD. */
2050 _bfd_generic_link_output_symbols (bfd *output_bfd,
2052 struct bfd_link_info *info,
2058 if (!bfd_generic_link_read_symbols (input_bfd))
2061 /* Create a filename symbol if we are supposed to. */
2062 if (info->create_object_symbols_section != NULL)
2066 for (sec = input_bfd->sections; sec != NULL; sec = sec->next)
2068 if (sec->output_section == info->create_object_symbols_section)
2072 newsym = bfd_make_empty_symbol (input_bfd);
2075 newsym->name = input_bfd->filename;
2077 newsym->flags = BSF_LOCAL | BSF_FILE;
2078 newsym->section = sec;
2080 if (! generic_add_output_symbol (output_bfd, psymalloc,
2089 /* Adjust the values of the globally visible symbols, and write out
2091 sym_ptr = _bfd_generic_link_get_symbols (input_bfd);
2092 sym_end = sym_ptr + _bfd_generic_link_get_symcount (input_bfd);
2093 for (; sym_ptr < sym_end; sym_ptr++)
2096 struct generic_link_hash_entry *h;
2101 if ((sym->flags & (BSF_INDIRECT
2106 || bfd_is_und_section (bfd_get_section (sym))
2107 || bfd_is_com_section (bfd_get_section (sym))
2108 || bfd_is_ind_section (bfd_get_section (sym)))
2110 if (sym->udata.p != NULL)
2111 h = (struct generic_link_hash_entry *) sym->udata.p;
2112 else if ((sym->flags & BSF_CONSTRUCTOR) != 0)
2114 /* This case normally means that the main linker code
2115 deliberately ignored this constructor symbol. We
2116 should just pass it through. This will screw up if
2117 the constructor symbol is from a different,
2118 non-generic, object file format, but the case will
2119 only arise when linking with -r, which will probably
2120 fail anyhow, since there will be no way to represent
2121 the relocs in the output format being used. */
2124 else if (bfd_is_und_section (bfd_get_section (sym)))
2125 h = ((struct generic_link_hash_entry *)
2126 bfd_wrapped_link_hash_lookup (output_bfd, info,
2127 bfd_asymbol_name (sym),
2128 FALSE, FALSE, TRUE));
2130 h = _bfd_generic_link_hash_lookup (_bfd_generic_hash_table (info),
2131 bfd_asymbol_name (sym),
2132 FALSE, FALSE, TRUE);
2136 /* Force all references to this symbol to point to
2137 the same area in memory. It is possible that
2138 this routine will be called with a hash table
2139 other than a generic hash table, so we double
2141 if (info->output_bfd->xvec == input_bfd->xvec)
2144 *sym_ptr = sym = h->sym;
2147 switch (h->root.type)
2150 case bfd_link_hash_new:
2152 case bfd_link_hash_undefined:
2154 case bfd_link_hash_undefweak:
2155 sym->flags |= BSF_WEAK;
2157 case bfd_link_hash_indirect:
2158 h = (struct generic_link_hash_entry *) h->root.u.i.link;
2160 case bfd_link_hash_defined:
2161 sym->flags |= BSF_GLOBAL;
2162 sym->flags &=~ BSF_CONSTRUCTOR;
2163 sym->value = h->root.u.def.value;
2164 sym->section = h->root.u.def.section;
2166 case bfd_link_hash_defweak:
2167 sym->flags |= BSF_WEAK;
2168 sym->flags &=~ BSF_CONSTRUCTOR;
2169 sym->value = h->root.u.def.value;
2170 sym->section = h->root.u.def.section;
2172 case bfd_link_hash_common:
2173 sym->value = h->root.u.c.size;
2174 sym->flags |= BSF_GLOBAL;
2175 if (! bfd_is_com_section (sym->section))
2177 BFD_ASSERT (bfd_is_und_section (sym->section));
2178 sym->section = bfd_com_section_ptr;
2180 /* We do not set the section of the symbol to
2181 h->root.u.c.p->section. That value was saved so
2182 that we would know where to allocate the symbol
2183 if it was defined. In this case the type is
2184 still bfd_link_hash_common, so we did not define
2185 it, so we do not want to use that section. */
2191 /* This switch is straight from the old code in
2192 write_file_locals in ldsym.c. */
2193 if (info->strip == strip_all
2194 || (info->strip == strip_some
2195 && bfd_hash_lookup (info->keep_hash, bfd_asymbol_name (sym),
2196 FALSE, FALSE) == NULL))
2198 else if ((sym->flags & (BSF_GLOBAL | BSF_WEAK)) != 0)
2200 /* If this symbol is marked as occurring now, rather
2201 than at the end, output it now. This is used for
2202 COFF C_EXT FCN symbols. FIXME: There must be a
2204 if (bfd_asymbol_bfd (sym) == input_bfd
2205 && (sym->flags & BSF_NOT_AT_END) != 0)
2210 else if (bfd_is_ind_section (sym->section))
2212 else if ((sym->flags & BSF_DEBUGGING) != 0)
2214 if (info->strip == strip_none)
2219 else if (bfd_is_und_section (sym->section)
2220 || bfd_is_com_section (sym->section))
2222 else if ((sym->flags & BSF_LOCAL) != 0)
2224 if ((sym->flags & BSF_WARNING) != 0)
2228 switch (info->discard)
2234 case discard_sec_merge:
2236 if (info->relocatable
2237 || ! (sym->section->flags & SEC_MERGE))
2241 if (bfd_is_local_label (input_bfd, sym))
2252 else if ((sym->flags & BSF_CONSTRUCTOR))
2254 if (info->strip != strip_all)
2259 else if (sym->flags == 0
2260 && (sym->section->owner->flags & BFD_PLUGIN) != 0)
2261 /* LTO doesn't set symbol information. We get here with the
2262 generic linker for a symbol that was "common" but no longer
2263 needs to be global. */
2268 /* If this symbol is in a section which is not being included
2269 in the output file, then we don't want to output the
2271 if (!bfd_is_abs_section (sym->section)
2272 && bfd_section_removed_from_list (output_bfd,
2273 sym->section->output_section))
2278 if (! generic_add_output_symbol (output_bfd, psymalloc, sym))
2288 /* Set the section and value of a generic BFD symbol based on a linker
2289 hash table entry. */
2292 set_symbol_from_hash (asymbol *sym, struct bfd_link_hash_entry *h)
2299 case bfd_link_hash_new:
2300 /* This can happen when a constructor symbol is seen but we are
2301 not building constructors. */
2302 if (sym->section != NULL)
2304 BFD_ASSERT ((sym->flags & BSF_CONSTRUCTOR) != 0);
2308 sym->flags |= BSF_CONSTRUCTOR;
2309 sym->section = bfd_abs_section_ptr;
2313 case bfd_link_hash_undefined:
2314 sym->section = bfd_und_section_ptr;
2317 case bfd_link_hash_undefweak:
2318 sym->section = bfd_und_section_ptr;
2320 sym->flags |= BSF_WEAK;
2322 case bfd_link_hash_defined:
2323 sym->section = h->u.def.section;
2324 sym->value = h->u.def.value;
2326 case bfd_link_hash_defweak:
2327 sym->flags |= BSF_WEAK;
2328 sym->section = h->u.def.section;
2329 sym->value = h->u.def.value;
2331 case bfd_link_hash_common:
2332 sym->value = h->u.c.size;
2333 if (sym->section == NULL)
2334 sym->section = bfd_com_section_ptr;
2335 else if (! bfd_is_com_section (sym->section))
2337 BFD_ASSERT (bfd_is_und_section (sym->section));
2338 sym->section = bfd_com_section_ptr;
2340 /* Do not set the section; see _bfd_generic_link_output_symbols. */
2342 case bfd_link_hash_indirect:
2343 case bfd_link_hash_warning:
2344 /* FIXME: What should we do here? */
2349 /* Write out a global symbol, if it hasn't already been written out.
2350 This is called for each symbol in the hash table. */
2353 _bfd_generic_link_write_global_symbol (struct generic_link_hash_entry *h,
2356 struct generic_write_global_symbol_info *wginfo =
2357 (struct generic_write_global_symbol_info *) data;
2365 if (wginfo->info->strip == strip_all
2366 || (wginfo->info->strip == strip_some
2367 && bfd_hash_lookup (wginfo->info->keep_hash, h->root.root.string,
2368 FALSE, FALSE) == NULL))
2375 sym = bfd_make_empty_symbol (wginfo->output_bfd);
2378 sym->name = h->root.root.string;
2382 set_symbol_from_hash (sym, &h->root);
2384 sym->flags |= BSF_GLOBAL;
2386 if (! generic_add_output_symbol (wginfo->output_bfd, wginfo->psymalloc,
2389 /* FIXME: No way to return failure. */
2396 /* Create a relocation. */
2399 _bfd_generic_reloc_link_order (bfd *abfd,
2400 struct bfd_link_info *info,
2402 struct bfd_link_order *link_order)
2406 if (! info->relocatable)
2408 if (sec->orelocation == NULL)
2411 r = (arelent *) bfd_alloc (abfd, sizeof (arelent));
2415 r->address = link_order->offset;
2416 r->howto = bfd_reloc_type_lookup (abfd, link_order->u.reloc.p->reloc);
2419 bfd_set_error (bfd_error_bad_value);
2423 /* Get the symbol to use for the relocation. */
2424 if (link_order->type == bfd_section_reloc_link_order)
2425 r->sym_ptr_ptr = link_order->u.reloc.p->u.section->symbol_ptr_ptr;
2428 struct generic_link_hash_entry *h;
2430 h = ((struct generic_link_hash_entry *)
2431 bfd_wrapped_link_hash_lookup (abfd, info,
2432 link_order->u.reloc.p->u.name,
2433 FALSE, FALSE, TRUE));
2437 if (! ((*info->callbacks->unattached_reloc)
2438 (info, link_order->u.reloc.p->u.name, NULL, NULL, 0)))
2440 bfd_set_error (bfd_error_bad_value);
2443 r->sym_ptr_ptr = &h->sym;
2446 /* If this is an inplace reloc, write the addend to the object file.
2447 Otherwise, store it in the reloc addend. */
2448 if (! r->howto->partial_inplace)
2449 r->addend = link_order->u.reloc.p->addend;
2453 bfd_reloc_status_type rstat;
2458 size = bfd_get_reloc_size (r->howto);
2459 buf = (bfd_byte *) bfd_zmalloc (size);
2462 rstat = _bfd_relocate_contents (r->howto, abfd,
2463 (bfd_vma) link_order->u.reloc.p->addend,
2470 case bfd_reloc_outofrange:
2472 case bfd_reloc_overflow:
2473 if (! ((*info->callbacks->reloc_overflow)
2475 (link_order->type == bfd_section_reloc_link_order
2476 ? bfd_section_name (abfd, link_order->u.reloc.p->u.section)
2477 : link_order->u.reloc.p->u.name),
2478 r->howto->name, link_order->u.reloc.p->addend,
2486 loc = link_order->offset * bfd_octets_per_byte (abfd);
2487 ok = bfd_set_section_contents (abfd, sec, buf, loc, size);
2495 sec->orelocation[sec->reloc_count] = r;
2501 /* Allocate a new link_order for a section. */
2503 struct bfd_link_order *
2504 bfd_new_link_order (bfd *abfd, asection *section)
2506 bfd_size_type amt = sizeof (struct bfd_link_order);
2507 struct bfd_link_order *new_lo;
2509 new_lo = (struct bfd_link_order *) bfd_zalloc (abfd, amt);
2513 new_lo->type = bfd_undefined_link_order;
2515 if (section->map_tail.link_order != NULL)
2516 section->map_tail.link_order->next = new_lo;
2518 section->map_head.link_order = new_lo;
2519 section->map_tail.link_order = new_lo;
2524 /* Default link order processing routine. Note that we can not handle
2525 the reloc_link_order types here, since they depend upon the details
2526 of how the particular backends generates relocs. */
2529 _bfd_default_link_order (bfd *abfd,
2530 struct bfd_link_info *info,
2532 struct bfd_link_order *link_order)
2534 switch (link_order->type)
2536 case bfd_undefined_link_order:
2537 case bfd_section_reloc_link_order:
2538 case bfd_symbol_reloc_link_order:
2541 case bfd_indirect_link_order:
2542 return default_indirect_link_order (abfd, info, sec, link_order,
2544 case bfd_data_link_order:
2545 return default_data_link_order (abfd, info, sec, link_order);
2549 /* Default routine to handle a bfd_data_link_order. */
2552 default_data_link_order (bfd *abfd,
2553 struct bfd_link_info *info ATTRIBUTE_UNUSED,
2555 struct bfd_link_order *link_order)
2563 BFD_ASSERT ((sec->flags & SEC_HAS_CONTENTS) != 0);
2565 size = link_order->size;
2569 fill = link_order->u.data.contents;
2570 fill_size = link_order->u.data.size;
2573 fill = abfd->arch_info->fill (size, bfd_big_endian (abfd),
2574 (sec->flags & SEC_CODE) != 0);
2578 else if (fill_size < size)
2581 fill = (bfd_byte *) bfd_malloc (size);
2586 memset (p, (int) link_order->u.data.contents[0], (size_t) size);
2591 memcpy (p, link_order->u.data.contents, fill_size);
2595 while (size >= fill_size);
2597 memcpy (p, link_order->u.data.contents, (size_t) size);
2598 size = link_order->size;
2602 loc = link_order->offset * bfd_octets_per_byte (abfd);
2603 result = bfd_set_section_contents (abfd, sec, fill, loc, size);
2605 if (fill != link_order->u.data.contents)
2610 /* Default routine to handle a bfd_indirect_link_order. */
2613 default_indirect_link_order (bfd *output_bfd,
2614 struct bfd_link_info *info,
2615 asection *output_section,
2616 struct bfd_link_order *link_order,
2617 bfd_boolean generic_linker)
2619 asection *input_section;
2621 bfd_byte *contents = NULL;
2622 bfd_byte *new_contents;
2623 bfd_size_type sec_size;
2626 BFD_ASSERT ((output_section->flags & SEC_HAS_CONTENTS) != 0);
2628 input_section = link_order->u.indirect.section;
2629 input_bfd = input_section->owner;
2630 if (input_section->size == 0)
2633 BFD_ASSERT (input_section->output_section == output_section);
2634 BFD_ASSERT (input_section->output_offset == link_order->offset);
2635 BFD_ASSERT (input_section->size == link_order->size);
2637 if (info->relocatable
2638 && input_section->reloc_count > 0
2639 && output_section->orelocation == NULL)
2641 /* Space has not been allocated for the output relocations.
2642 This can happen when we are called by a specific backend
2643 because somebody is attempting to link together different
2644 types of object files. Handling this case correctly is
2645 difficult, and sometimes impossible. */
2646 (*_bfd_error_handler)
2647 (_("Attempt to do relocatable link with %s input and %s output"),
2648 bfd_get_target (input_bfd), bfd_get_target (output_bfd));
2649 bfd_set_error (bfd_error_wrong_format);
2653 if (! generic_linker)
2658 /* Get the canonical symbols. The generic linker will always
2659 have retrieved them by this point, but we are being called by
2660 a specific linker, presumably because we are linking
2661 different types of object files together. */
2662 if (!bfd_generic_link_read_symbols (input_bfd))
2665 /* Since we have been called by a specific linker, rather than
2666 the generic linker, the values of the symbols will not be
2667 right. They will be the values as seen in the input file,
2668 not the values of the final link. We need to fix them up
2669 before we can relocate the section. */
2670 sympp = _bfd_generic_link_get_symbols (input_bfd);
2671 symppend = sympp + _bfd_generic_link_get_symcount (input_bfd);
2672 for (; sympp < symppend; sympp++)
2675 struct bfd_link_hash_entry *h;
2679 if ((sym->flags & (BSF_INDIRECT
2684 || bfd_is_und_section (bfd_get_section (sym))
2685 || bfd_is_com_section (bfd_get_section (sym))
2686 || bfd_is_ind_section (bfd_get_section (sym)))
2688 /* sym->udata may have been set by
2689 generic_link_add_symbol_list. */
2690 if (sym->udata.p != NULL)
2691 h = (struct bfd_link_hash_entry *) sym->udata.p;
2692 else if (bfd_is_und_section (bfd_get_section (sym)))
2693 h = bfd_wrapped_link_hash_lookup (output_bfd, info,
2694 bfd_asymbol_name (sym),
2695 FALSE, FALSE, TRUE);
2697 h = bfd_link_hash_lookup (info->hash,
2698 bfd_asymbol_name (sym),
2699 FALSE, FALSE, TRUE);
2701 set_symbol_from_hash (sym, h);
2706 if ((output_section->flags & (SEC_GROUP | SEC_LINKER_CREATED)) == SEC_GROUP
2707 && input_section->size != 0)
2709 /* Group section contents are set by bfd_elf_set_group_contents. */
2710 if (!output_bfd->output_has_begun)
2712 /* FIXME: This hack ensures bfd_elf_set_group_contents is called. */
2713 if (!bfd_set_section_contents (output_bfd, output_section, "", 0, 1))
2716 new_contents = output_section->contents;
2717 BFD_ASSERT (new_contents != NULL);
2718 BFD_ASSERT (input_section->output_offset == 0);
2722 /* Get and relocate the section contents. */
2723 sec_size = (input_section->rawsize > input_section->size
2724 ? input_section->rawsize
2725 : input_section->size);
2726 contents = (bfd_byte *) bfd_malloc (sec_size);
2727 if (contents == NULL && sec_size != 0)
2729 new_contents = (bfd_get_relocated_section_contents
2730 (output_bfd, info, link_order, contents,
2732 _bfd_generic_link_get_symbols (input_bfd)));
2737 /* Output the section contents. */
2738 loc = input_section->output_offset * bfd_octets_per_byte (output_bfd);
2739 if (! bfd_set_section_contents (output_bfd, output_section,
2740 new_contents, loc, input_section->size))
2743 if (contents != NULL)
2748 if (contents != NULL)
2753 /* A little routine to count the number of relocs in a link_order
2757 _bfd_count_link_order_relocs (struct bfd_link_order *link_order)
2759 register unsigned int c;
2760 register struct bfd_link_order *l;
2763 for (l = link_order; l != NULL; l = l->next)
2765 if (l->type == bfd_section_reloc_link_order
2766 || l->type == bfd_symbol_reloc_link_order)
2775 bfd_link_split_section
2778 bfd_boolean bfd_link_split_section (bfd *abfd, asection *sec);
2781 Return nonzero if @var{sec} should be split during a
2782 reloceatable or final link.
2784 .#define bfd_link_split_section(abfd, sec) \
2785 . BFD_SEND (abfd, _bfd_link_split_section, (abfd, sec))
2791 _bfd_generic_link_split_section (bfd *abfd ATTRIBUTE_UNUSED,
2792 asection *sec ATTRIBUTE_UNUSED)
2799 bfd_section_already_linked
2802 bfd_boolean bfd_section_already_linked (bfd *abfd,
2804 struct bfd_link_info *info);
2807 Check if @var{data} has been already linked during a reloceatable
2808 or final link. Return TRUE if it has.
2810 .#define bfd_section_already_linked(abfd, sec, info) \
2811 . BFD_SEND (abfd, _section_already_linked, (abfd, sec, info))
2816 /* Sections marked with the SEC_LINK_ONCE flag should only be linked
2817 once into the output. This routine checks each section, and
2818 arrange to discard it if a section of the same name has already
2819 been linked. This code assumes that all relevant sections have the
2820 SEC_LINK_ONCE flag set; that is, it does not depend solely upon the
2821 section name. bfd_section_already_linked is called via
2822 bfd_map_over_sections. */
2824 /* The hash table. */
2826 static struct bfd_hash_table _bfd_section_already_linked_table;
2828 /* Support routines for the hash table used by section_already_linked,
2829 initialize the table, traverse, lookup, fill in an entry and remove
2833 bfd_section_already_linked_table_traverse
2834 (bfd_boolean (*func) (struct bfd_section_already_linked_hash_entry *,
2835 void *), void *info)
2837 bfd_hash_traverse (&_bfd_section_already_linked_table,
2838 (bfd_boolean (*) (struct bfd_hash_entry *,
2843 struct bfd_section_already_linked_hash_entry *
2844 bfd_section_already_linked_table_lookup (const char *name)
2846 return ((struct bfd_section_already_linked_hash_entry *)
2847 bfd_hash_lookup (&_bfd_section_already_linked_table, name,
2852 bfd_section_already_linked_table_insert
2853 (struct bfd_section_already_linked_hash_entry *already_linked_list,
2856 struct bfd_section_already_linked *l;
2858 /* Allocate the memory from the same obstack as the hash table is
2860 l = (struct bfd_section_already_linked *)
2861 bfd_hash_allocate (&_bfd_section_already_linked_table, sizeof *l);
2865 l->next = already_linked_list->entry;
2866 already_linked_list->entry = l;
2870 static struct bfd_hash_entry *
2871 already_linked_newfunc (struct bfd_hash_entry *entry ATTRIBUTE_UNUSED,
2872 struct bfd_hash_table *table,
2873 const char *string ATTRIBUTE_UNUSED)
2875 struct bfd_section_already_linked_hash_entry *ret =
2876 (struct bfd_section_already_linked_hash_entry *)
2877 bfd_hash_allocate (table, sizeof *ret);
2888 bfd_section_already_linked_table_init (void)
2890 return bfd_hash_table_init_n (&_bfd_section_already_linked_table,
2891 already_linked_newfunc,
2892 sizeof (struct bfd_section_already_linked_hash_entry),
2897 bfd_section_already_linked_table_free (void)
2899 bfd_hash_table_free (&_bfd_section_already_linked_table);
2902 /* Report warnings as appropriate for duplicate section SEC.
2903 Return FALSE if we decide to keep SEC after all. */
2906 _bfd_handle_already_linked (asection *sec,
2907 struct bfd_section_already_linked *l,
2908 struct bfd_link_info *info)
2910 switch (sec->flags & SEC_LINK_DUPLICATES)
2915 case SEC_LINK_DUPLICATES_DISCARD:
2916 /* If we found an LTO IR match for this comdat group on
2917 the first pass, replace it with the LTO output on the
2918 second pass. We can't simply choose real object
2919 files over IR because the first pass may contain a
2920 mix of LTO and normal objects and we must keep the
2921 first match, be it IR or real. */
2922 if (info->loading_lto_outputs
2923 && (l->sec->owner->flags & BFD_PLUGIN) != 0)
2930 case SEC_LINK_DUPLICATES_ONE_ONLY:
2931 info->callbacks->einfo
2932 (_("%B: ignoring duplicate section `%A'\n"),
2936 case SEC_LINK_DUPLICATES_SAME_SIZE:
2937 if ((l->sec->owner->flags & BFD_PLUGIN) != 0)
2939 else if (sec->size != l->sec->size)
2940 info->callbacks->einfo
2941 (_("%B: duplicate section `%A' has different size\n"),
2945 case SEC_LINK_DUPLICATES_SAME_CONTENTS:
2946 if ((l->sec->owner->flags & BFD_PLUGIN) != 0)
2948 else if (sec->size != l->sec->size)
2949 info->callbacks->einfo
2950 (_("%B: duplicate section `%A' has different size\n"),
2952 else if (sec->size != 0)
2954 bfd_byte *sec_contents, *l_sec_contents = NULL;
2956 if (!bfd_malloc_and_get_section (sec->owner, sec, &sec_contents))
2957 info->callbacks->einfo
2958 (_("%B: could not read contents of section `%A'\n"),
2960 else if (!bfd_malloc_and_get_section (l->sec->owner, l->sec,
2962 info->callbacks->einfo
2963 (_("%B: could not read contents of section `%A'\n"),
2964 l->sec->owner, l->sec);
2965 else if (memcmp (sec_contents, l_sec_contents, sec->size) != 0)
2966 info->callbacks->einfo
2967 (_("%B: duplicate section `%A' has different contents\n"),
2971 free (sec_contents);
2973 free (l_sec_contents);
2978 /* Set the output_section field so that lang_add_section
2979 does not create a lang_input_section structure for this
2980 section. Since there might be a symbol in the section
2981 being discarded, we must retain a pointer to the section
2982 which we are really going to use. */
2983 sec->output_section = bfd_abs_section_ptr;
2984 sec->kept_section = l->sec;
2988 /* This is used on non-ELF inputs. */
2991 _bfd_generic_section_already_linked (bfd *abfd ATTRIBUTE_UNUSED,
2993 struct bfd_link_info *info)
2996 struct bfd_section_already_linked *l;
2997 struct bfd_section_already_linked_hash_entry *already_linked_list;
2999 if ((sec->flags & SEC_LINK_ONCE) == 0)
3002 /* The generic linker doesn't handle section groups. */
3003 if ((sec->flags & SEC_GROUP) != 0)
3006 /* FIXME: When doing a relocatable link, we may have trouble
3007 copying relocations in other sections that refer to local symbols
3008 in the section being discarded. Those relocations will have to
3009 be converted somehow; as of this writing I'm not sure that any of
3010 the backends handle that correctly.
3012 It is tempting to instead not discard link once sections when
3013 doing a relocatable link (technically, they should be discarded
3014 whenever we are building constructors). However, that fails,
3015 because the linker winds up combining all the link once sections
3016 into a single large link once section, which defeats the purpose
3017 of having link once sections in the first place. */
3019 name = bfd_get_section_name (abfd, sec);
3021 already_linked_list = bfd_section_already_linked_table_lookup (name);
3023 l = already_linked_list->entry;
3026 /* The section has already been linked. See if we should
3028 return _bfd_handle_already_linked (sec, l, info);
3031 /* This is the first section with this name. Record it. */
3032 if (!bfd_section_already_linked_table_insert (already_linked_list, sec))
3033 info->callbacks->einfo (_("%F%P: already_linked_table: %E\n"));
3037 /* Choose a neighbouring section to S in OBFD that will be output, or
3038 the absolute section if ADDR is out of bounds of the neighbours. */
3041 _bfd_nearby_section (bfd *obfd, asection *s, bfd_vma addr)
3043 asection *next, *prev, *best;
3045 /* Find preceding kept section. */
3046 for (prev = s->prev; prev != NULL; prev = prev->prev)
3047 if ((prev->flags & SEC_EXCLUDE) == 0
3048 && !bfd_section_removed_from_list (obfd, prev))
3051 /* Find following kept section. Start at prev->next because
3052 other sections may have been added after S was removed. */
3053 if (s->prev != NULL)
3054 next = s->prev->next;
3056 next = s->owner->sections;
3057 for (; next != NULL; next = next->next)
3058 if ((next->flags & SEC_EXCLUDE) == 0
3059 && !bfd_section_removed_from_list (obfd, next))
3062 /* Choose better of two sections, based on flags. The idea
3063 is to choose a section that will be in the same segment
3064 as S would have been if it was kept. */
3069 best = bfd_abs_section_ptr;
3071 else if (next == NULL)
3073 else if (((prev->flags ^ next->flags)
3074 & (SEC_ALLOC | SEC_THREAD_LOCAL | SEC_LOAD)) != 0)
3076 if (((next->flags ^ s->flags)
3077 & (SEC_ALLOC | SEC_THREAD_LOCAL)) != 0
3078 /* We prefer to choose a loaded section. Section S
3079 doesn't have SEC_LOAD set (it being excluded, that
3080 part of the flag processing didn't happen) so we
3081 can't compare that flag to those of NEXT and PREV. */
3082 || ((prev->flags & SEC_LOAD) != 0
3083 && (next->flags & SEC_LOAD) == 0))
3086 else if (((prev->flags ^ next->flags) & SEC_READONLY) != 0)
3088 if (((next->flags ^ s->flags) & SEC_READONLY) != 0)
3091 else if (((prev->flags ^ next->flags) & SEC_CODE) != 0)
3093 if (((next->flags ^ s->flags) & SEC_CODE) != 0)
3098 /* Flags we care about are the same. Prefer the following
3099 section if that will result in a positive valued sym. */
3100 if (addr < next->vma)
3107 /* Convert symbols in excluded output sections to use a kept section. */
3110 fix_syms (struct bfd_link_hash_entry *h, void *data)
3112 bfd *obfd = (bfd *) data;
3114 if (h->type == bfd_link_hash_defined
3115 || h->type == bfd_link_hash_defweak)
3117 asection *s = h->u.def.section;
3119 && s->output_section != NULL
3120 && (s->output_section->flags & SEC_EXCLUDE) != 0
3121 && bfd_section_removed_from_list (obfd, s->output_section))
3125 h->u.def.value += s->output_offset + s->output_section->vma;
3126 op = _bfd_nearby_section (obfd, s->output_section, h->u.def.value);
3127 h->u.def.value -= op->vma;
3128 h->u.def.section = op;
3136 _bfd_fix_excluded_sec_syms (bfd *obfd, struct bfd_link_info *info)
3138 bfd_link_hash_traverse (info->hash, fix_syms, obfd);
3143 bfd_generic_define_common_symbol
3146 bfd_boolean bfd_generic_define_common_symbol
3147 (bfd *output_bfd, struct bfd_link_info *info,
3148 struct bfd_link_hash_entry *h);
3151 Convert common symbol @var{h} into a defined symbol.
3152 Return TRUE on success and FALSE on failure.
3154 .#define bfd_define_common_symbol(output_bfd, info, h) \
3155 . BFD_SEND (output_bfd, _bfd_define_common_symbol, (output_bfd, info, h))
3160 bfd_generic_define_common_symbol (bfd *output_bfd,
3161 struct bfd_link_info *info ATTRIBUTE_UNUSED,
3162 struct bfd_link_hash_entry *h)
3164 unsigned int power_of_two;
3165 bfd_vma alignment, size;
3168 BFD_ASSERT (h != NULL && h->type == bfd_link_hash_common);
3171 power_of_two = h->u.c.p->alignment_power;
3172 section = h->u.c.p->section;
3174 /* Increase the size of the section to align the common symbol.
3175 The alignment must be a power of two. */
3176 alignment = bfd_octets_per_byte (output_bfd) << power_of_two;
3177 BFD_ASSERT (alignment != 0 && (alignment & -alignment) == alignment);
3178 section->size += alignment - 1;
3179 section->size &= -alignment;
3181 /* Adjust the section's overall alignment if necessary. */
3182 if (power_of_two > section->alignment_power)
3183 section->alignment_power = power_of_two;
3185 /* Change the symbol from common to defined. */
3186 h->type = bfd_link_hash_defined;
3187 h->u.def.section = section;
3188 h->u.def.value = section->size;
3190 /* Increase the size of the section. */
3191 section->size += size;
3193 /* Make sure the section is allocated in memory, and make sure that
3194 it is no longer a common section. */
3195 section->flags |= SEC_ALLOC;
3196 section->flags &= ~SEC_IS_COMMON;
3202 bfd_find_version_for_sym
3205 struct bfd_elf_version_tree * bfd_find_version_for_sym
3206 (struct bfd_elf_version_tree *verdefs,
3207 const char *sym_name, bfd_boolean *hide);
3210 Search an elf version script tree for symbol versioning
3211 info and export / don't-export status for a given symbol.
3212 Return non-NULL on success and NULL on failure; also sets
3213 the output @samp{hide} boolean parameter.
3217 struct bfd_elf_version_tree *
3218 bfd_find_version_for_sym (struct bfd_elf_version_tree *verdefs,
3219 const char *sym_name,
3222 struct bfd_elf_version_tree *t;
3223 struct bfd_elf_version_tree *local_ver, *global_ver, *exist_ver;
3224 struct bfd_elf_version_tree *star_local_ver, *star_global_ver;
3228 star_local_ver = NULL;
3229 star_global_ver = NULL;
3231 for (t = verdefs; t != NULL; t = t->next)
3233 if (t->globals.list != NULL)
3235 struct bfd_elf_version_expr *d = NULL;
3237 while ((d = (*t->match) (&t->globals, d, sym_name)) != NULL)
3239 if (d->literal || strcmp (d->pattern, "*") != 0)
3242 star_global_ver = t;
3246 /* If the match is a wildcard pattern, keep looking for
3247 a more explicit, perhaps even local, match. */
3256 if (t->locals.list != NULL)
3258 struct bfd_elf_version_expr *d = NULL;
3260 while ((d = (*t->match) (&t->locals, d, sym_name)) != NULL)
3262 if (d->literal || strcmp (d->pattern, "*") != 0)
3266 /* If the match is a wildcard pattern, keep looking for
3267 a more explicit, perhaps even global, match. */
3270 /* An exact match overrides a global wildcard. */
3272 star_global_ver = NULL;
3282 if (global_ver == NULL && local_ver == NULL)
3283 global_ver = star_global_ver;
3285 if (global_ver != NULL)
3287 /* If we already have a versioned symbol that matches the
3288 node for this symbol, then we don't want to create a
3289 duplicate from the unversioned symbol. Instead hide the
3290 unversioned symbol. */
3291 *hide = exist_ver == global_ver;
3295 if (local_ver == NULL)
3296 local_ver = star_local_ver;
3298 if (local_ver != NULL)
3309 bfd_hide_sym_by_version
3312 bfd_boolean bfd_hide_sym_by_version
3313 (struct bfd_elf_version_tree *verdefs, const char *sym_name);
3316 Search an elf version script tree for symbol versioning
3317 info for a given symbol. Return TRUE if the symbol is hidden.
3322 bfd_hide_sym_by_version (struct bfd_elf_version_tree *verdefs,
3323 const char *sym_name)
3325 bfd_boolean hidden = FALSE;
3326 bfd_find_version_for_sym (verdefs, sym_name, &hidden);