[PATCH 2/57][Arm][GAS] Add support for MVE instructions: vpst, vadd, vsub and vabd
[binutils-gdb.git] / bfd / linker.c
blob9e89c84d15943deccae3664e6536bcf46c45077d
1 /* linker.c -- BFD linker routines
2 Copyright (C) 1993-2019 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. */
22 #include "sysdep.h"
23 #include "bfd.h"
24 #include "libbfd.h"
25 #include "bfdlink.h"
26 #include "genlink.h"
29 SECTION
30 Linker Functions
32 @cindex Linker
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
38 memory.
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
55 proper.
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.
63 @menu
64 @* Creating a Linker Hash Table::
65 @* Adding Symbols to the Hash Table::
66 @* Performing the Final Link::
67 @end menu
69 INODE
70 Creating a Linker Hash Table, Adding Symbols to the Hash Table, Linker Functions, Linker Functions
71 SUBSECTION
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
99 pointer to it.
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.
107 INODE
108 Adding Symbols to the Hash Table, Performing the Final Link, Creating a Linker Hash Table, Linker Functions
109 SUBSECTION
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
122 link.
124 The a.out version of this entry point is
125 <<NAME(aout,link_add_symbols)>>.
127 @menu
128 @* Differing file formats::
129 @* Adding symbols from an object file::
130 @* Adding symbols from an archive::
131 @end menu
133 INODE
134 Differing file formats, Adding symbols from an object file, Adding Symbols to the Hash Table, Adding Symbols to the Hash Table
135 SUBSUBSECTION
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
168 hash table entry.
170 INODE
171 Adding symbols from an object file, Adding symbols from an archive, Differing file formats, Adding Symbols to the Hash Table
172 SUBSUBSECTION
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.
214 INODE
215 Adding symbols from an archive, , Adding symbols from an object file, Adding Symbols to the Hash Table
216 SUBSUBSECTION
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.
262 INODE
263 Performing the Final Link, , Adding Symbols to the Hash Table, Linker Functions
264 SUBSECTION
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)>>.
288 @menu
289 @* Information provided by the linker::
290 @* Relocating the section contents::
291 @* Writing the symbol table::
292 @end menu
294 INODE
295 Information provided by the linker, Relocating the section contents, Performing the Final Link, Performing the Final Link
296 SUBSUBSECTION
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.
318 INODE
319 Relocating the section contents, Writing the symbol table, Information provided by the linker, Performing the Final Link
320 SUBSUBSECTION
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>>.
356 INODE
357 Writing the symbol table, , Relocating the section contents, Performing the Final Link
358 SUBSUBSECTION
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 *);
407 static bfd_boolean generic_link_check_archive_element
408 (bfd *, struct bfd_link_info *, struct bfd_link_hash_entry *, const char *,
409 bfd_boolean *);
410 static bfd_boolean generic_link_add_symbol_list
411 (bfd *, struct bfd_link_info *, bfd_size_type count, asymbol **);
412 static bfd_boolean generic_add_output_symbol
413 (bfd *, size_t *psymalloc, asymbol *);
414 static bfd_boolean default_data_link_order
415 (bfd *, struct bfd_link_info *, asection *, struct bfd_link_order *);
416 static bfd_boolean default_indirect_link_order
417 (bfd *, struct bfd_link_info *, asection *, struct bfd_link_order *,
418 bfd_boolean);
420 /* The link hash table structure is defined in bfdlink.h. It provides
421 a base hash table which the backend specific hash tables are built
422 upon. */
424 /* Routine to create an entry in the link hash table. */
426 struct bfd_hash_entry *
427 _bfd_link_hash_newfunc (struct bfd_hash_entry *entry,
428 struct bfd_hash_table *table,
429 const char *string)
431 /* Allocate the structure if it has not already been allocated by a
432 subclass. */
433 if (entry == NULL)
435 entry = (struct bfd_hash_entry *)
436 bfd_hash_allocate (table, sizeof (struct bfd_link_hash_entry));
437 if (entry == NULL)
438 return entry;
441 /* Call the allocation method of the superclass. */
442 entry = bfd_hash_newfunc (entry, table, string);
443 if (entry)
445 struct bfd_link_hash_entry *h = (struct bfd_link_hash_entry *) entry;
447 /* Initialize the local fields. */
448 memset ((char *) &h->root + sizeof (h->root), 0,
449 sizeof (*h) - sizeof (h->root));
452 return entry;
455 /* Initialize a link hash table. The BFD argument is the one
456 responsible for creating this table. */
458 bfd_boolean
459 _bfd_link_hash_table_init
460 (struct bfd_link_hash_table *table,
461 bfd *abfd ATTRIBUTE_UNUSED,
462 struct bfd_hash_entry *(*newfunc) (struct bfd_hash_entry *,
463 struct bfd_hash_table *,
464 const char *),
465 unsigned int entsize)
467 bfd_boolean ret;
469 BFD_ASSERT (!abfd->is_linker_output && !abfd->link.hash);
470 table->undefs = NULL;
471 table->undefs_tail = NULL;
472 table->type = bfd_link_generic_hash_table;
474 ret = bfd_hash_table_init (&table->table, newfunc, entsize);
475 if (ret)
477 /* Arrange for destruction of this hash table on closing ABFD. */
478 table->hash_table_free = _bfd_generic_link_hash_table_free;
479 abfd->link.hash = table;
480 abfd->is_linker_output = TRUE;
482 return ret;
485 /* Look up a symbol in a link hash table. If follow is TRUE, we
486 follow bfd_link_hash_indirect and bfd_link_hash_warning links to
487 the real symbol.
489 .{* Return TRUE if the symbol described by a linker hash entry H
490 . is going to be absolute. Linker-script defined symbols can be
491 . converted from absolute to section-relative ones late in the
492 . link. Use this macro to correctly determine whether the symbol
493 . will actually end up absolute in output. *}
494 .#define bfd_is_abs_symbol(H) \
495 . (((H)->type == bfd_link_hash_defined \
496 . || (H)->type == bfd_link_hash_defweak) \
497 . && bfd_is_abs_section ((H)->u.def.section) \
498 . && !(H)->rel_from_abs)
502 struct bfd_link_hash_entry *
503 bfd_link_hash_lookup (struct bfd_link_hash_table *table,
504 const char *string,
505 bfd_boolean create,
506 bfd_boolean copy,
507 bfd_boolean follow)
509 struct bfd_link_hash_entry *ret;
511 if (table == NULL || string == NULL)
512 return NULL;
514 ret = ((struct bfd_link_hash_entry *)
515 bfd_hash_lookup (&table->table, string, create, copy));
517 if (follow && ret != NULL)
519 while (ret->type == bfd_link_hash_indirect
520 || ret->type == bfd_link_hash_warning)
521 ret = ret->u.i.link;
524 return ret;
527 /* Look up a symbol in the main linker hash table if the symbol might
528 be wrapped. This should only be used for references to an
529 undefined symbol, not for definitions of a symbol. */
531 struct bfd_link_hash_entry *
532 bfd_wrapped_link_hash_lookup (bfd *abfd,
533 struct bfd_link_info *info,
534 const char *string,
535 bfd_boolean create,
536 bfd_boolean copy,
537 bfd_boolean follow)
539 bfd_size_type amt;
541 if (info->wrap_hash != NULL)
543 const char *l;
544 char prefix = '\0';
546 l = string;
547 if (*l == bfd_get_symbol_leading_char (abfd) || *l == info->wrap_char)
549 prefix = *l;
550 ++l;
553 #undef WRAP
554 #define WRAP "__wrap_"
556 if (bfd_hash_lookup (info->wrap_hash, l, FALSE, FALSE) != NULL)
558 char *n;
559 struct bfd_link_hash_entry *h;
561 /* This symbol is being wrapped. We want to replace all
562 references to SYM with references to __wrap_SYM. */
564 amt = strlen (l) + sizeof WRAP + 1;
565 n = (char *) bfd_malloc (amt);
566 if (n == NULL)
567 return NULL;
569 n[0] = prefix;
570 n[1] = '\0';
571 strcat (n, WRAP);
572 strcat (n, l);
573 h = bfd_link_hash_lookup (info->hash, n, create, TRUE, follow);
574 free (n);
575 return h;
578 #undef REAL
579 #define REAL "__real_"
581 if (*l == '_'
582 && CONST_STRNEQ (l, REAL)
583 && bfd_hash_lookup (info->wrap_hash, l + sizeof REAL - 1,
584 FALSE, FALSE) != NULL)
586 char *n;
587 struct bfd_link_hash_entry *h;
589 /* This is a reference to __real_SYM, where SYM is being
590 wrapped. We want to replace all references to __real_SYM
591 with references to SYM. */
593 amt = strlen (l + sizeof REAL - 1) + 2;
594 n = (char *) bfd_malloc (amt);
595 if (n == NULL)
596 return NULL;
598 n[0] = prefix;
599 n[1] = '\0';
600 strcat (n, l + sizeof REAL - 1);
601 h = bfd_link_hash_lookup (info->hash, n, create, TRUE, follow);
602 free (n);
603 return h;
606 #undef REAL
609 return bfd_link_hash_lookup (info->hash, string, create, copy, follow);
612 /* If H is a wrapped symbol, ie. the symbol name starts with "__wrap_"
613 and the remainder is found in wrap_hash, return the real symbol. */
615 struct bfd_link_hash_entry *
616 unwrap_hash_lookup (struct bfd_link_info *info,
617 bfd *input_bfd,
618 struct bfd_link_hash_entry *h)
620 const char *l = h->root.string;
622 if (*l == bfd_get_symbol_leading_char (input_bfd)
623 || *l == info->wrap_char)
624 ++l;
626 if (CONST_STRNEQ (l, WRAP))
628 l += sizeof WRAP - 1;
630 if (bfd_hash_lookup (info->wrap_hash, l, FALSE, FALSE) != NULL)
632 char save = 0;
633 if (l - (sizeof WRAP - 1) != h->root.string)
635 --l;
636 save = *l;
637 *(char *) l = *h->root.string;
639 h = bfd_link_hash_lookup (info->hash, l, FALSE, FALSE, FALSE);
640 if (save)
641 *(char *) l = save;
644 return h;
646 #undef WRAP
648 /* Traverse a generic link hash table. Differs from bfd_hash_traverse
649 in the treatment of warning symbols. When warning symbols are
650 created they replace the real symbol, so you don't get to see the
651 real symbol in a bfd_hash_traverse. This traversal calls func with
652 the real symbol. */
654 void
655 bfd_link_hash_traverse
656 (struct bfd_link_hash_table *htab,
657 bfd_boolean (*func) (struct bfd_link_hash_entry *, void *),
658 void *info)
660 unsigned int i;
662 htab->table.frozen = 1;
663 for (i = 0; i < htab->table.size; i++)
665 struct bfd_link_hash_entry *p;
667 p = (struct bfd_link_hash_entry *) htab->table.table[i];
668 for (; p != NULL; p = (struct bfd_link_hash_entry *) p->root.next)
669 if (!(*func) (p->type == bfd_link_hash_warning ? p->u.i.link : p, info))
670 goto out;
672 out:
673 htab->table.frozen = 0;
676 /* Add a symbol to the linker hash table undefs list. */
678 void
679 bfd_link_add_undef (struct bfd_link_hash_table *table,
680 struct bfd_link_hash_entry *h)
682 BFD_ASSERT (h->u.undef.next == NULL);
683 if (table->undefs_tail != NULL)
684 table->undefs_tail->u.undef.next = h;
685 if (table->undefs == NULL)
686 table->undefs = h;
687 table->undefs_tail = h;
690 /* The undefs list was designed so that in normal use we don't need to
691 remove entries. However, if symbols on the list are changed from
692 bfd_link_hash_undefined to either bfd_link_hash_undefweak or
693 bfd_link_hash_new for some reason, then they must be removed from the
694 list. Failure to do so might result in the linker attempting to add
695 the symbol to the list again at a later stage. */
697 void
698 bfd_link_repair_undef_list (struct bfd_link_hash_table *table)
700 struct bfd_link_hash_entry **pun;
702 pun = &table->undefs;
703 while (*pun != NULL)
705 struct bfd_link_hash_entry *h = *pun;
707 if (h->type == bfd_link_hash_new
708 || h->type == bfd_link_hash_undefweak)
710 *pun = h->u.undef.next;
711 h->u.undef.next = NULL;
712 if (h == table->undefs_tail)
714 if (pun == &table->undefs)
715 table->undefs_tail = NULL;
716 else
717 /* pun points at an u.undef.next field. Go back to
718 the start of the link_hash_entry. */
719 table->undefs_tail = (struct bfd_link_hash_entry *)
720 ((char *) pun - ((char *) &h->u.undef.next - (char *) h));
721 break;
724 else
725 pun = &h->u.undef.next;
729 /* Routine to create an entry in a generic link hash table. */
731 struct bfd_hash_entry *
732 _bfd_generic_link_hash_newfunc (struct bfd_hash_entry *entry,
733 struct bfd_hash_table *table,
734 const char *string)
736 /* Allocate the structure if it has not already been allocated by a
737 subclass. */
738 if (entry == NULL)
740 entry = (struct bfd_hash_entry *)
741 bfd_hash_allocate (table, sizeof (struct generic_link_hash_entry));
742 if (entry == NULL)
743 return entry;
746 /* Call the allocation method of the superclass. */
747 entry = _bfd_link_hash_newfunc (entry, table, string);
748 if (entry)
750 struct generic_link_hash_entry *ret;
752 /* Set local fields. */
753 ret = (struct generic_link_hash_entry *) entry;
754 ret->written = FALSE;
755 ret->sym = NULL;
758 return entry;
761 /* Create a generic link hash table. */
763 struct bfd_link_hash_table *
764 _bfd_generic_link_hash_table_create (bfd *abfd)
766 struct generic_link_hash_table *ret;
767 bfd_size_type amt = sizeof (struct generic_link_hash_table);
769 ret = (struct generic_link_hash_table *) bfd_malloc (amt);
770 if (ret == NULL)
771 return NULL;
772 if (! _bfd_link_hash_table_init (&ret->root, abfd,
773 _bfd_generic_link_hash_newfunc,
774 sizeof (struct generic_link_hash_entry)))
776 free (ret);
777 return NULL;
779 return &ret->root;
782 void
783 _bfd_generic_link_hash_table_free (bfd *obfd)
785 struct generic_link_hash_table *ret;
787 BFD_ASSERT (obfd->is_linker_output && obfd->link.hash);
788 ret = (struct generic_link_hash_table *) obfd->link.hash;
789 bfd_hash_table_free (&ret->root.table);
790 free (ret);
791 obfd->link.hash = NULL;
792 obfd->is_linker_output = FALSE;
795 /* Grab the symbols for an object file when doing a generic link. We
796 store the symbols in the outsymbols field. We need to keep them
797 around for the entire link to ensure that we only read them once.
798 If we read them multiple times, we might wind up with relocs and
799 the hash table pointing to different instances of the symbol
800 structure. */
802 bfd_boolean
803 bfd_generic_link_read_symbols (bfd *abfd)
805 if (bfd_get_outsymbols (abfd) == NULL)
807 long symsize;
808 long symcount;
810 symsize = bfd_get_symtab_upper_bound (abfd);
811 if (symsize < 0)
812 return FALSE;
813 bfd_get_outsymbols (abfd) = (struct bfd_symbol **) bfd_alloc (abfd,
814 symsize);
815 if (bfd_get_outsymbols (abfd) == NULL && symsize != 0)
816 return FALSE;
817 symcount = bfd_canonicalize_symtab (abfd, bfd_get_outsymbols (abfd));
818 if (symcount < 0)
819 return FALSE;
820 bfd_get_symcount (abfd) = symcount;
823 return TRUE;
826 /* Indicate that we are only retrieving symbol values from this
827 section. We want the symbols to act as though the values in the
828 file are absolute. */
830 void
831 _bfd_generic_link_just_syms (asection *sec,
832 struct bfd_link_info *info ATTRIBUTE_UNUSED)
834 sec->sec_info_type = SEC_INFO_TYPE_JUST_SYMS;
835 sec->output_section = bfd_abs_section_ptr;
836 sec->output_offset = sec->vma;
839 /* Copy the symbol type and other attributes for a linker script
840 assignment from HSRC to HDEST.
841 The default implementation does nothing. */
842 void
843 _bfd_generic_copy_link_hash_symbol_type (bfd *abfd ATTRIBUTE_UNUSED,
844 struct bfd_link_hash_entry *hdest ATTRIBUTE_UNUSED,
845 struct bfd_link_hash_entry *hsrc ATTRIBUTE_UNUSED)
849 /* Generic function to add symbols from an object file to the
850 global hash table. */
852 bfd_boolean
853 _bfd_generic_link_add_symbols (bfd *abfd, struct bfd_link_info *info)
855 bfd_boolean ret;
857 switch (bfd_get_format (abfd))
859 case bfd_object:
860 ret = generic_link_add_object_symbols (abfd, info);
861 break;
862 case bfd_archive:
863 ret = (_bfd_generic_link_add_archive_symbols
864 (abfd, info, generic_link_check_archive_element));
865 break;
866 default:
867 bfd_set_error (bfd_error_wrong_format);
868 ret = FALSE;
871 return ret;
874 /* Add symbols from an object file to the global hash table. */
876 static bfd_boolean
877 generic_link_add_object_symbols (bfd *abfd,
878 struct bfd_link_info *info)
880 bfd_size_type symcount;
881 struct bfd_symbol **outsyms;
883 if (!bfd_generic_link_read_symbols (abfd))
884 return FALSE;
885 symcount = _bfd_generic_link_get_symcount (abfd);
886 outsyms = _bfd_generic_link_get_symbols (abfd);
887 return generic_link_add_symbol_list (abfd, info, symcount, outsyms);
890 /* Generic function to add symbols from an archive file to the global
891 hash file. This function presumes that the archive symbol table
892 has already been read in (this is normally done by the
893 bfd_check_format entry point). It looks through the archive symbol
894 table for symbols that are undefined or common in the linker global
895 symbol hash table. When one is found, the CHECKFN argument is used
896 to see if an object file should be included. This allows targets
897 to customize common symbol behaviour. CHECKFN should set *PNEEDED
898 to TRUE if the object file should be included, and must also call
899 the bfd_link_info add_archive_element callback function and handle
900 adding the symbols to the global hash table. CHECKFN must notice
901 if the callback indicates a substitute BFD, and arrange to add
902 those symbols instead if it does so. CHECKFN should only return
903 FALSE if some sort of error occurs. */
905 bfd_boolean
906 _bfd_generic_link_add_archive_symbols
907 (bfd *abfd,
908 struct bfd_link_info *info,
909 bfd_boolean (*checkfn) (bfd *, struct bfd_link_info *,
910 struct bfd_link_hash_entry *, const char *,
911 bfd_boolean *))
913 bfd_boolean loop;
914 bfd_size_type amt;
915 unsigned char *included;
917 if (! bfd_has_map (abfd))
919 /* An empty archive is a special case. */
920 if (bfd_openr_next_archived_file (abfd, NULL) == NULL)
921 return TRUE;
922 bfd_set_error (bfd_error_no_armap);
923 return FALSE;
926 amt = bfd_ardata (abfd)->symdef_count;
927 if (amt == 0)
928 return TRUE;
929 amt *= sizeof (*included);
930 included = (unsigned char *) bfd_zmalloc (amt);
931 if (included == NULL)
932 return FALSE;
936 carsym *arsyms;
937 carsym *arsym_end;
938 carsym *arsym;
939 unsigned int indx;
940 file_ptr last_ar_offset = -1;
941 bfd_boolean needed = FALSE;
942 bfd *element = NULL;
944 loop = FALSE;
945 arsyms = bfd_ardata (abfd)->symdefs;
946 arsym_end = arsyms + bfd_ardata (abfd)->symdef_count;
947 for (arsym = arsyms, indx = 0; arsym < arsym_end; arsym++, indx++)
949 struct bfd_link_hash_entry *h;
950 struct bfd_link_hash_entry *undefs_tail;
952 if (included[indx])
953 continue;
954 if (needed && arsym->file_offset == last_ar_offset)
956 included[indx] = 1;
957 continue;
960 if (arsym->name == NULL)
961 goto error_return;
963 h = bfd_link_hash_lookup (info->hash, arsym->name,
964 FALSE, FALSE, TRUE);
966 if (h == NULL
967 && info->pei386_auto_import
968 && CONST_STRNEQ (arsym->name, "__imp_"))
969 h = bfd_link_hash_lookup (info->hash, arsym->name + 6,
970 FALSE, FALSE, TRUE);
971 if (h == NULL)
972 continue;
974 if (h->type != bfd_link_hash_undefined
975 && h->type != bfd_link_hash_common)
977 if (h->type != bfd_link_hash_undefweak)
978 /* Symbol must be defined. Don't check it again. */
979 included[indx] = 1;
980 continue;
983 if (last_ar_offset != arsym->file_offset)
985 last_ar_offset = arsym->file_offset;
986 element = _bfd_get_elt_at_filepos (abfd, last_ar_offset);
987 if (element == NULL
988 || !bfd_check_format (element, bfd_object))
989 goto error_return;
992 undefs_tail = info->hash->undefs_tail;
994 /* CHECKFN will see if this element should be included, and
995 go ahead and include it if appropriate. */
996 if (! (*checkfn) (element, info, h, arsym->name, &needed))
997 goto error_return;
999 if (needed)
1001 unsigned int mark;
1003 /* Look backward to mark all symbols from this object file
1004 which we have already seen in this pass. */
1005 mark = indx;
1008 included[mark] = 1;
1009 if (mark == 0)
1010 break;
1011 --mark;
1013 while (arsyms[mark].file_offset == last_ar_offset);
1015 if (undefs_tail != info->hash->undefs_tail)
1016 loop = TRUE;
1019 } while (loop);
1021 free (included);
1022 return TRUE;
1024 error_return:
1025 free (included);
1026 return FALSE;
1029 /* See if we should include an archive element. */
1031 static bfd_boolean
1032 generic_link_check_archive_element (bfd *abfd,
1033 struct bfd_link_info *info,
1034 struct bfd_link_hash_entry *h,
1035 const char *name ATTRIBUTE_UNUSED,
1036 bfd_boolean *pneeded)
1038 asymbol **pp, **ppend;
1040 *pneeded = FALSE;
1042 if (!bfd_generic_link_read_symbols (abfd))
1043 return FALSE;
1045 pp = _bfd_generic_link_get_symbols (abfd);
1046 ppend = pp + _bfd_generic_link_get_symcount (abfd);
1047 for (; pp < ppend; pp++)
1049 asymbol *p;
1051 p = *pp;
1053 /* We are only interested in globally visible symbols. */
1054 if (! bfd_is_com_section (p->section)
1055 && (p->flags & (BSF_GLOBAL | BSF_INDIRECT | BSF_WEAK)) == 0)
1056 continue;
1058 /* We are only interested if we know something about this
1059 symbol, and it is undefined or common. An undefined weak
1060 symbol (type bfd_link_hash_undefweak) is not considered to be
1061 a reference when pulling files out of an archive. See the
1062 SVR4 ABI, p. 4-27. */
1063 h = bfd_link_hash_lookup (info->hash, bfd_asymbol_name (p), FALSE,
1064 FALSE, TRUE);
1065 if (h == NULL
1066 || (h->type != bfd_link_hash_undefined
1067 && h->type != bfd_link_hash_common))
1068 continue;
1070 /* P is a symbol we are looking for. */
1072 if (! bfd_is_com_section (p->section)
1073 || (h->type == bfd_link_hash_undefined
1074 && h->u.undef.abfd == NULL))
1076 /* P is not a common symbol, or an undefined reference was
1077 created from outside BFD such as from a linker -u option.
1078 This object file defines the symbol, so pull it in. */
1079 *pneeded = TRUE;
1080 if (!(*info->callbacks
1081 ->add_archive_element) (info, abfd, bfd_asymbol_name (p),
1082 &abfd))
1083 return FALSE;
1084 /* Potentially, the add_archive_element hook may have set a
1085 substitute BFD for us. */
1086 return bfd_link_add_symbols (abfd, info);
1089 /* P is a common symbol. */
1091 if (h->type == bfd_link_hash_undefined)
1093 bfd *symbfd;
1094 bfd_vma size;
1095 unsigned int power;
1097 /* Turn the symbol into a common symbol but do not link in
1098 the object file. This is how a.out works. Object
1099 formats that require different semantics must implement
1100 this function differently. This symbol is already on the
1101 undefs list. We add the section to a common section
1102 attached to symbfd to ensure that it is in a BFD which
1103 will be linked in. */
1104 symbfd = h->u.undef.abfd;
1105 h->type = bfd_link_hash_common;
1106 h->u.c.p = (struct bfd_link_hash_common_entry *)
1107 bfd_hash_allocate (&info->hash->table,
1108 sizeof (struct bfd_link_hash_common_entry));
1109 if (h->u.c.p == NULL)
1110 return FALSE;
1112 size = bfd_asymbol_value (p);
1113 h->u.c.size = size;
1115 power = bfd_log2 (size);
1116 if (power > 4)
1117 power = 4;
1118 h->u.c.p->alignment_power = power;
1120 if (p->section == bfd_com_section_ptr)
1121 h->u.c.p->section = bfd_make_section_old_way (symbfd, "COMMON");
1122 else
1123 h->u.c.p->section = bfd_make_section_old_way (symbfd,
1124 p->section->name);
1125 h->u.c.p->section->flags |= SEC_ALLOC;
1127 else
1129 /* Adjust the size of the common symbol if necessary. This
1130 is how a.out works. Object formats that require
1131 different semantics must implement this function
1132 differently. */
1133 if (bfd_asymbol_value (p) > h->u.c.size)
1134 h->u.c.size = bfd_asymbol_value (p);
1138 /* This archive element is not needed. */
1139 return TRUE;
1142 /* Add the symbols from an object file to the global hash table. ABFD
1143 is the object file. INFO is the linker information. SYMBOL_COUNT
1144 is the number of symbols. SYMBOLS is the list of symbols. */
1146 static bfd_boolean
1147 generic_link_add_symbol_list (bfd *abfd,
1148 struct bfd_link_info *info,
1149 bfd_size_type symbol_count,
1150 asymbol **symbols)
1152 asymbol **pp, **ppend;
1154 pp = symbols;
1155 ppend = symbols + symbol_count;
1156 for (; pp < ppend; pp++)
1158 asymbol *p;
1160 p = *pp;
1162 if ((p->flags & (BSF_INDIRECT
1163 | BSF_WARNING
1164 | BSF_GLOBAL
1165 | BSF_CONSTRUCTOR
1166 | BSF_WEAK)) != 0
1167 || bfd_is_und_section (bfd_get_section (p))
1168 || bfd_is_com_section (bfd_get_section (p))
1169 || bfd_is_ind_section (bfd_get_section (p)))
1171 const char *name;
1172 const char *string;
1173 struct generic_link_hash_entry *h;
1174 struct bfd_link_hash_entry *bh;
1176 string = name = bfd_asymbol_name (p);
1177 if (((p->flags & BSF_INDIRECT) != 0
1178 || bfd_is_ind_section (p->section))
1179 && pp + 1 < ppend)
1181 pp++;
1182 string = bfd_asymbol_name (*pp);
1184 else if ((p->flags & BSF_WARNING) != 0
1185 && pp + 1 < ppend)
1187 /* The name of P is actually the warning string, and the
1188 next symbol is the one to warn about. */
1189 pp++;
1190 name = bfd_asymbol_name (*pp);
1193 bh = NULL;
1194 if (! (_bfd_generic_link_add_one_symbol
1195 (info, abfd, name, p->flags, bfd_get_section (p),
1196 p->value, string, FALSE, FALSE, &bh)))
1197 return FALSE;
1198 h = (struct generic_link_hash_entry *) bh;
1200 /* If this is a constructor symbol, and the linker didn't do
1201 anything with it, then we want to just pass the symbol
1202 through to the output file. This will happen when
1203 linking with -r. */
1204 if ((p->flags & BSF_CONSTRUCTOR) != 0
1205 && (h == NULL || h->root.type == bfd_link_hash_new))
1207 p->udata.p = NULL;
1208 continue;
1211 /* Save the BFD symbol so that we don't lose any backend
1212 specific information that may be attached to it. We only
1213 want this one if it gives more information than the
1214 existing one; we don't want to replace a defined symbol
1215 with an undefined one. This routine may be called with a
1216 hash table other than the generic hash table, so we only
1217 do this if we are certain that the hash table is a
1218 generic one. */
1219 if (info->output_bfd->xvec == abfd->xvec)
1221 if (h->sym == NULL
1222 || (! bfd_is_und_section (bfd_get_section (p))
1223 && (! bfd_is_com_section (bfd_get_section (p))
1224 || bfd_is_und_section (bfd_get_section (h->sym)))))
1226 h->sym = p;
1227 /* BSF_OLD_COMMON is a hack to support COFF reloc
1228 reading, and it should go away when the COFF
1229 linker is switched to the new version. */
1230 if (bfd_is_com_section (bfd_get_section (p)))
1231 p->flags |= BSF_OLD_COMMON;
1235 /* Store a back pointer from the symbol to the hash
1236 table entry for the benefit of relaxation code until
1237 it gets rewritten to not use asymbol structures.
1238 Setting this is also used to check whether these
1239 symbols were set up by the generic linker. */
1240 p->udata.p = h;
1244 return TRUE;
1247 /* We use a state table to deal with adding symbols from an object
1248 file. The first index into the state table describes the symbol
1249 from the object file. The second index into the state table is the
1250 type of the symbol in the hash table. */
1252 /* The symbol from the object file is turned into one of these row
1253 values. */
1255 enum link_row
1257 UNDEF_ROW, /* Undefined. */
1258 UNDEFW_ROW, /* Weak undefined. */
1259 DEF_ROW, /* Defined. */
1260 DEFW_ROW, /* Weak defined. */
1261 COMMON_ROW, /* Common. */
1262 INDR_ROW, /* Indirect. */
1263 WARN_ROW, /* Warning. */
1264 SET_ROW /* Member of set. */
1267 /* apparently needed for Hitachi 3050R(HI-UX/WE2)? */
1268 #undef FAIL
1270 /* The actions to take in the state table. */
1272 enum link_action
1274 FAIL, /* Abort. */
1275 UND, /* Mark symbol undefined. */
1276 WEAK, /* Mark symbol weak undefined. */
1277 DEF, /* Mark symbol defined. */
1278 DEFW, /* Mark symbol weak defined. */
1279 COM, /* Mark symbol common. */
1280 REF, /* Mark defined symbol referenced. */
1281 CREF, /* Possibly warn about common reference to defined symbol. */
1282 CDEF, /* Define existing common symbol. */
1283 NOACT, /* No action. */
1284 BIG, /* Mark symbol common using largest size. */
1285 MDEF, /* Multiple definition error. */
1286 MIND, /* Multiple indirect symbols. */
1287 IND, /* Make indirect symbol. */
1288 CIND, /* Make indirect symbol from existing common symbol. */
1289 SET, /* Add value to set. */
1290 MWARN, /* Make warning symbol. */
1291 WARN, /* Warn if referenced, else MWARN. */
1292 CYCLE, /* Repeat with symbol pointed to. */
1293 REFC, /* Mark indirect symbol referenced and then CYCLE. */
1294 WARNC /* Issue warning and then CYCLE. */
1297 /* The state table itself. The first index is a link_row and the
1298 second index is a bfd_link_hash_type. */
1300 static const enum link_action link_action[8][8] =
1302 /* current\prev new undef undefw def defw com indr warn */
1303 /* UNDEF_ROW */ {UND, NOACT, UND, REF, REF, NOACT, REFC, WARNC },
1304 /* UNDEFW_ROW */ {WEAK, NOACT, NOACT, REF, REF, NOACT, REFC, WARNC },
1305 /* DEF_ROW */ {DEF, DEF, DEF, MDEF, DEF, CDEF, MDEF, CYCLE },
1306 /* DEFW_ROW */ {DEFW, DEFW, DEFW, NOACT, NOACT, NOACT, NOACT, CYCLE },
1307 /* COMMON_ROW */ {COM, COM, COM, CREF, COM, BIG, REFC, WARNC },
1308 /* INDR_ROW */ {IND, IND, IND, MDEF, IND, CIND, MIND, CYCLE },
1309 /* WARN_ROW */ {MWARN, WARN, WARN, WARN, WARN, WARN, WARN, NOACT },
1310 /* SET_ROW */ {SET, SET, SET, SET, SET, SET, CYCLE, CYCLE }
1313 /* Most of the entries in the LINK_ACTION table are straightforward,
1314 but a few are somewhat subtle.
1316 A reference to an indirect symbol (UNDEF_ROW/indr or
1317 UNDEFW_ROW/indr) is counted as a reference both to the indirect
1318 symbol and to the symbol the indirect symbol points to.
1320 A reference to a warning symbol (UNDEF_ROW/warn or UNDEFW_ROW/warn)
1321 causes the warning to be issued.
1323 A common definition of an indirect symbol (COMMON_ROW/indr) is
1324 treated as a multiple definition error. Likewise for an indirect
1325 definition of a common symbol (INDR_ROW/com).
1327 An indirect definition of a warning (INDR_ROW/warn) does not cause
1328 the warning to be issued.
1330 If a warning is created for an indirect symbol (WARN_ROW/indr) no
1331 warning is created for the symbol the indirect symbol points to.
1333 Adding an entry to a set does not count as a reference to a set,
1334 and no warning is issued (SET_ROW/warn). */
1336 /* Return the BFD in which a hash entry has been defined, if known. */
1338 static bfd *
1339 hash_entry_bfd (struct bfd_link_hash_entry *h)
1341 while (h->type == bfd_link_hash_warning)
1342 h = h->u.i.link;
1343 switch (h->type)
1345 default:
1346 return NULL;
1347 case bfd_link_hash_undefined:
1348 case bfd_link_hash_undefweak:
1349 return h->u.undef.abfd;
1350 case bfd_link_hash_defined:
1351 case bfd_link_hash_defweak:
1352 return h->u.def.section->owner;
1353 case bfd_link_hash_common:
1354 return h->u.c.p->section->owner;
1356 /*NOTREACHED*/
1359 /* Add a symbol to the global hash table.
1360 ABFD is the BFD the symbol comes from.
1361 NAME is the name of the symbol.
1362 FLAGS is the BSF_* bits associated with the symbol.
1363 SECTION is the section in which the symbol is defined; this may be
1364 bfd_und_section_ptr or bfd_com_section_ptr.
1365 VALUE is the value of the symbol, relative to the section.
1366 STRING is used for either an indirect symbol, in which case it is
1367 the name of the symbol to indirect to, or a warning symbol, in
1368 which case it is the warning string.
1369 COPY is TRUE if NAME or STRING must be copied into locally
1370 allocated memory if they need to be saved.
1371 COLLECT is TRUE if we should automatically collect gcc constructor
1372 or destructor names as collect2 does.
1373 HASHP, if not NULL, is a place to store the created hash table
1374 entry; if *HASHP is not NULL, the caller has already looked up
1375 the hash table entry, and stored it in *HASHP. */
1377 bfd_boolean
1378 _bfd_generic_link_add_one_symbol (struct bfd_link_info *info,
1379 bfd *abfd,
1380 const char *name,
1381 flagword flags,
1382 asection *section,
1383 bfd_vma value,
1384 const char *string,
1385 bfd_boolean copy,
1386 bfd_boolean collect,
1387 struct bfd_link_hash_entry **hashp)
1389 enum link_row row;
1390 struct bfd_link_hash_entry *h;
1391 struct bfd_link_hash_entry *inh = NULL;
1392 bfd_boolean cycle;
1394 BFD_ASSERT (section != NULL);
1396 if (bfd_is_ind_section (section)
1397 || (flags & BSF_INDIRECT) != 0)
1399 row = INDR_ROW;
1400 /* Create the indirect symbol here. This is for the benefit of
1401 the plugin "notice" function.
1402 STRING is the name of the symbol we want to indirect to. */
1403 inh = bfd_wrapped_link_hash_lookup (abfd, info, string, TRUE,
1404 copy, FALSE);
1405 if (inh == NULL)
1406 return FALSE;
1408 else if ((flags & BSF_WARNING) != 0)
1409 row = WARN_ROW;
1410 else if ((flags & BSF_CONSTRUCTOR) != 0)
1411 row = SET_ROW;
1412 else if (bfd_is_und_section (section))
1414 if ((flags & BSF_WEAK) != 0)
1415 row = UNDEFW_ROW;
1416 else
1417 row = UNDEF_ROW;
1419 else if ((flags & BSF_WEAK) != 0)
1420 row = DEFW_ROW;
1421 else if (bfd_is_com_section (section))
1423 row = COMMON_ROW;
1424 if (!bfd_link_relocatable (info)
1425 && name[0] == '_'
1426 && name[1] == '_'
1427 && strcmp (name + (name[2] == '_'), "__gnu_lto_slim") == 0)
1428 _bfd_error_handler
1429 (_("%pB: plugin needed to handle lto object"), abfd);
1431 else
1432 row = DEF_ROW;
1434 if (hashp != NULL && *hashp != NULL)
1435 h = *hashp;
1436 else
1438 if (row == UNDEF_ROW || row == UNDEFW_ROW)
1439 h = bfd_wrapped_link_hash_lookup (abfd, info, name, TRUE, copy, FALSE);
1440 else
1441 h = bfd_link_hash_lookup (info->hash, name, TRUE, copy, FALSE);
1442 if (h == NULL)
1444 if (hashp != NULL)
1445 *hashp = NULL;
1446 return FALSE;
1450 if (info->notice_all
1451 || (info->notice_hash != NULL
1452 && bfd_hash_lookup (info->notice_hash, name, FALSE, FALSE) != NULL))
1454 if (! (*info->callbacks->notice) (info, h, inh,
1455 abfd, section, value, flags))
1456 return FALSE;
1459 if (hashp != NULL)
1460 *hashp = h;
1464 enum link_action action;
1465 int prev;
1467 prev = h->type;
1468 /* Treat symbols defined by early linker script pass as undefined. */
1469 if (h->ldscript_def)
1470 prev = bfd_link_hash_undefined;
1471 cycle = FALSE;
1472 action = link_action[(int) row][prev];
1473 switch (action)
1475 case FAIL:
1476 abort ();
1478 case NOACT:
1479 /* Do nothing. */
1480 break;
1482 case UND:
1483 /* Make a new undefined symbol. */
1484 h->type = bfd_link_hash_undefined;
1485 h->u.undef.abfd = abfd;
1486 bfd_link_add_undef (info->hash, h);
1487 break;
1489 case WEAK:
1490 /* Make a new weak undefined symbol. */
1491 h->type = bfd_link_hash_undefweak;
1492 h->u.undef.abfd = abfd;
1493 break;
1495 case CDEF:
1496 /* We have found a definition for a symbol which was
1497 previously common. */
1498 BFD_ASSERT (h->type == bfd_link_hash_common);
1499 (*info->callbacks->multiple_common) (info, h, abfd,
1500 bfd_link_hash_defined, 0);
1501 /* Fall through. */
1502 case DEF:
1503 case DEFW:
1505 enum bfd_link_hash_type oldtype;
1507 /* Define a symbol. */
1508 oldtype = h->type;
1509 if (action == DEFW)
1510 h->type = bfd_link_hash_defweak;
1511 else
1512 h->type = bfd_link_hash_defined;
1513 h->u.def.section = section;
1514 h->u.def.value = value;
1515 h->linker_def = 0;
1516 h->ldscript_def = 0;
1518 /* If we have been asked to, we act like collect2 and
1519 identify all functions that might be global
1520 constructors and destructors and pass them up in a
1521 callback. We only do this for certain object file
1522 types, since many object file types can handle this
1523 automatically. */
1524 if (collect && name[0] == '_')
1526 const char *s;
1528 /* A constructor or destructor name starts like this:
1529 _+GLOBAL_[_.$][ID][_.$] where the first [_.$] and
1530 the second are the same character (we accept any
1531 character there, in case a new object file format
1532 comes along with even worse naming restrictions). */
1534 #define CONS_PREFIX "GLOBAL_"
1535 #define CONS_PREFIX_LEN (sizeof CONS_PREFIX - 1)
1537 s = name + 1;
1538 while (*s == '_')
1539 ++s;
1540 if (s[0] == 'G' && CONST_STRNEQ (s, CONS_PREFIX))
1542 char c;
1544 c = s[CONS_PREFIX_LEN + 1];
1545 if ((c == 'I' || c == 'D')
1546 && s[CONS_PREFIX_LEN] == s[CONS_PREFIX_LEN + 2])
1548 /* If this is a definition of a symbol which
1549 was previously weakly defined, we are in
1550 trouble. We have already added a
1551 constructor entry for the weak defined
1552 symbol, and now we are trying to add one
1553 for the new symbol. Fortunately, this case
1554 should never arise in practice. */
1555 if (oldtype == bfd_link_hash_defweak)
1556 abort ();
1558 (*info->callbacks->constructor) (info, c == 'I',
1559 h->root.string, abfd,
1560 section, value);
1566 break;
1568 case COM:
1569 /* We have found a common definition for a symbol. */
1570 if (h->type == bfd_link_hash_new)
1571 bfd_link_add_undef (info->hash, h);
1572 h->type = bfd_link_hash_common;
1573 h->u.c.p = (struct bfd_link_hash_common_entry *)
1574 bfd_hash_allocate (&info->hash->table,
1575 sizeof (struct bfd_link_hash_common_entry));
1576 if (h->u.c.p == NULL)
1577 return FALSE;
1579 h->u.c.size = value;
1581 /* Select a default alignment based on the size. This may
1582 be overridden by the caller. */
1584 unsigned int power;
1586 power = bfd_log2 (value);
1587 if (power > 4)
1588 power = 4;
1589 h->u.c.p->alignment_power = power;
1592 /* The section of a common symbol is only used if the common
1593 symbol is actually allocated. It basically provides a
1594 hook for the linker script to decide which output section
1595 the common symbols should be put in. In most cases, the
1596 section of a common symbol will be bfd_com_section_ptr,
1597 the code here will choose a common symbol section named
1598 "COMMON", and the linker script will contain *(COMMON) in
1599 the appropriate place. A few targets use separate common
1600 sections for small symbols, and they require special
1601 handling. */
1602 if (section == bfd_com_section_ptr)
1604 h->u.c.p->section = bfd_make_section_old_way (abfd, "COMMON");
1605 h->u.c.p->section->flags |= SEC_ALLOC;
1607 else if (section->owner != abfd)
1609 h->u.c.p->section = bfd_make_section_old_way (abfd,
1610 section->name);
1611 h->u.c.p->section->flags |= SEC_ALLOC;
1613 else
1614 h->u.c.p->section = section;
1615 h->linker_def = 0;
1616 h->ldscript_def = 0;
1617 break;
1619 case REF:
1620 /* A reference to a defined symbol. */
1621 if (h->u.undef.next == NULL && info->hash->undefs_tail != h)
1622 h->u.undef.next = h;
1623 break;
1625 case BIG:
1626 /* We have found a common definition for a symbol which
1627 already had a common definition. Use the maximum of the
1628 two sizes, and use the section required by the larger symbol. */
1629 BFD_ASSERT (h->type == bfd_link_hash_common);
1630 (*info->callbacks->multiple_common) (info, h, abfd,
1631 bfd_link_hash_common, value);
1632 if (value > h->u.c.size)
1634 unsigned int power;
1636 h->u.c.size = value;
1638 /* Select a default alignment based on the size. This may
1639 be overridden by the caller. */
1640 power = bfd_log2 (value);
1641 if (power > 4)
1642 power = 4;
1643 h->u.c.p->alignment_power = power;
1645 /* Some systems have special treatment for small commons,
1646 hence we want to select the section used by the larger
1647 symbol. This makes sure the symbol does not go in a
1648 small common section if it is now too large. */
1649 if (section == bfd_com_section_ptr)
1651 h->u.c.p->section
1652 = bfd_make_section_old_way (abfd, "COMMON");
1653 h->u.c.p->section->flags |= SEC_ALLOC;
1655 else if (section->owner != abfd)
1657 h->u.c.p->section
1658 = bfd_make_section_old_way (abfd, section->name);
1659 h->u.c.p->section->flags |= SEC_ALLOC;
1661 else
1662 h->u.c.p->section = section;
1664 break;
1666 case CREF:
1667 /* We have found a common definition for a symbol which
1668 was already defined. */
1669 (*info->callbacks->multiple_common) (info, h, abfd,
1670 bfd_link_hash_common, value);
1671 break;
1673 case MIND:
1674 /* Multiple indirect symbols. This is OK if they both point
1675 to the same symbol. */
1676 if (strcmp (h->u.i.link->root.string, string) == 0)
1677 break;
1678 /* Fall through. */
1679 case MDEF:
1680 /* Handle a multiple definition. */
1681 (*info->callbacks->multiple_definition) (info, h,
1682 abfd, section, value);
1683 break;
1685 case CIND:
1686 /* Create an indirect symbol from an existing common symbol. */
1687 BFD_ASSERT (h->type == bfd_link_hash_common);
1688 (*info->callbacks->multiple_common) (info, h, abfd,
1689 bfd_link_hash_indirect, 0);
1690 /* Fall through. */
1691 case IND:
1692 if (inh->type == bfd_link_hash_indirect
1693 && inh->u.i.link == h)
1695 _bfd_error_handler
1696 /* xgettext:c-format */
1697 (_("%pB: indirect symbol `%s' to `%s' is a loop"),
1698 abfd, name, string);
1699 bfd_set_error (bfd_error_invalid_operation);
1700 return FALSE;
1702 if (inh->type == bfd_link_hash_new)
1704 inh->type = bfd_link_hash_undefined;
1705 inh->u.undef.abfd = abfd;
1706 bfd_link_add_undef (info->hash, inh);
1709 /* If the indirect symbol has been referenced, we need to
1710 push the reference down to the symbol we are referencing. */
1711 if (h->type != bfd_link_hash_new)
1713 /* ??? If inh->type == bfd_link_hash_undefweak this
1714 converts inh to bfd_link_hash_undefined. */
1715 row = UNDEF_ROW;
1716 cycle = TRUE;
1719 h->type = bfd_link_hash_indirect;
1720 h->u.i.link = inh;
1721 /* Not setting h = h->u.i.link here means that when cycle is
1722 set above we'll always go to REFC, and then cycle again
1723 to the indirected symbol. This means that any successful
1724 change of an existing symbol to indirect counts as a
1725 reference. ??? That may not be correct when the existing
1726 symbol was defweak. */
1727 break;
1729 case SET:
1730 /* Add an entry to a set. */
1731 (*info->callbacks->add_to_set) (info, h, BFD_RELOC_CTOR,
1732 abfd, section, value);
1733 break;
1735 case WARNC:
1736 /* Issue a warning and cycle, except when the reference is
1737 in LTO IR. */
1738 if (h->u.i.warning != NULL
1739 && (abfd->flags & BFD_PLUGIN) == 0)
1741 (*info->callbacks->warning) (info, h->u.i.warning,
1742 h->root.string, abfd, NULL, 0);
1743 /* Only issue a warning once. */
1744 h->u.i.warning = NULL;
1746 /* Fall through. */
1747 case CYCLE:
1748 /* Try again with the referenced symbol. */
1749 h = h->u.i.link;
1750 cycle = TRUE;
1751 break;
1753 case REFC:
1754 /* A reference to an indirect symbol. */
1755 if (h->u.undef.next == NULL && info->hash->undefs_tail != h)
1756 h->u.undef.next = h;
1757 h = h->u.i.link;
1758 cycle = TRUE;
1759 break;
1761 case WARN:
1762 /* Warn if this symbol has been referenced already from non-IR,
1763 otherwise add a warning. */
1764 if ((!info->lto_plugin_active
1765 && (h->u.undef.next != NULL || info->hash->undefs_tail == h))
1766 || h->non_ir_ref_regular
1767 || h->non_ir_ref_dynamic)
1769 (*info->callbacks->warning) (info, string, h->root.string,
1770 hash_entry_bfd (h), NULL, 0);
1771 break;
1773 /* Fall through. */
1774 case MWARN:
1775 /* Make a warning symbol. */
1777 struct bfd_link_hash_entry *sub;
1779 /* STRING is the warning to give. */
1780 sub = ((struct bfd_link_hash_entry *)
1781 ((*info->hash->table.newfunc)
1782 (NULL, &info->hash->table, h->root.string)));
1783 if (sub == NULL)
1784 return FALSE;
1785 *sub = *h;
1786 sub->type = bfd_link_hash_warning;
1787 sub->u.i.link = h;
1788 if (! copy)
1789 sub->u.i.warning = string;
1790 else
1792 char *w;
1793 size_t len = strlen (string) + 1;
1795 w = (char *) bfd_hash_allocate (&info->hash->table, len);
1796 if (w == NULL)
1797 return FALSE;
1798 memcpy (w, string, len);
1799 sub->u.i.warning = w;
1802 bfd_hash_replace (&info->hash->table,
1803 (struct bfd_hash_entry *) h,
1804 (struct bfd_hash_entry *) sub);
1805 if (hashp != NULL)
1806 *hashp = sub;
1808 break;
1811 while (cycle);
1813 return TRUE;
1816 /* Generic final link routine. */
1818 bfd_boolean
1819 _bfd_generic_final_link (bfd *abfd, struct bfd_link_info *info)
1821 bfd *sub;
1822 asection *o;
1823 struct bfd_link_order *p;
1824 size_t outsymalloc;
1825 struct generic_write_global_symbol_info wginfo;
1827 bfd_get_outsymbols (abfd) = NULL;
1828 bfd_get_symcount (abfd) = 0;
1829 outsymalloc = 0;
1831 /* Mark all sections which will be included in the output file. */
1832 for (o = abfd->sections; o != NULL; o = o->next)
1833 for (p = o->map_head.link_order; p != NULL; p = p->next)
1834 if (p->type == bfd_indirect_link_order)
1835 p->u.indirect.section->linker_mark = TRUE;
1837 /* Build the output symbol table. */
1838 for (sub = info->input_bfds; sub != NULL; sub = sub->link.next)
1839 if (! _bfd_generic_link_output_symbols (abfd, sub, info, &outsymalloc))
1840 return FALSE;
1842 /* Accumulate the global symbols. */
1843 wginfo.info = info;
1844 wginfo.output_bfd = abfd;
1845 wginfo.psymalloc = &outsymalloc;
1846 _bfd_generic_link_hash_traverse (_bfd_generic_hash_table (info),
1847 _bfd_generic_link_write_global_symbol,
1848 &wginfo);
1850 /* Make sure we have a trailing NULL pointer on OUTSYMBOLS. We
1851 shouldn't really need one, since we have SYMCOUNT, but some old
1852 code still expects one. */
1853 if (! generic_add_output_symbol (abfd, &outsymalloc, NULL))
1854 return FALSE;
1856 if (bfd_link_relocatable (info))
1858 /* Allocate space for the output relocs for each section. */
1859 for (o = abfd->sections; o != NULL; o = o->next)
1861 o->reloc_count = 0;
1862 for (p = o->map_head.link_order; p != NULL; p = p->next)
1864 if (p->type == bfd_section_reloc_link_order
1865 || p->type == bfd_symbol_reloc_link_order)
1866 ++o->reloc_count;
1867 else if (p->type == bfd_indirect_link_order)
1869 asection *input_section;
1870 bfd *input_bfd;
1871 long relsize;
1872 arelent **relocs;
1873 asymbol **symbols;
1874 long reloc_count;
1876 input_section = p->u.indirect.section;
1877 input_bfd = input_section->owner;
1878 relsize = bfd_get_reloc_upper_bound (input_bfd,
1879 input_section);
1880 if (relsize < 0)
1881 return FALSE;
1882 relocs = (arelent **) bfd_malloc (relsize);
1883 if (!relocs && relsize != 0)
1884 return FALSE;
1885 symbols = _bfd_generic_link_get_symbols (input_bfd);
1886 reloc_count = bfd_canonicalize_reloc (input_bfd,
1887 input_section,
1888 relocs,
1889 symbols);
1890 free (relocs);
1891 if (reloc_count < 0)
1892 return FALSE;
1893 BFD_ASSERT ((unsigned long) reloc_count
1894 == input_section->reloc_count);
1895 o->reloc_count += reloc_count;
1898 if (o->reloc_count > 0)
1900 bfd_size_type amt;
1902 amt = o->reloc_count;
1903 amt *= sizeof (arelent *);
1904 o->orelocation = (struct reloc_cache_entry **) bfd_alloc (abfd, amt);
1905 if (!o->orelocation)
1906 return FALSE;
1907 o->flags |= SEC_RELOC;
1908 /* Reset the count so that it can be used as an index
1909 when putting in the output relocs. */
1910 o->reloc_count = 0;
1915 /* Handle all the link order information for the sections. */
1916 for (o = abfd->sections; o != NULL; o = o->next)
1918 for (p = o->map_head.link_order; p != NULL; p = p->next)
1920 switch (p->type)
1922 case bfd_section_reloc_link_order:
1923 case bfd_symbol_reloc_link_order:
1924 if (! _bfd_generic_reloc_link_order (abfd, info, o, p))
1925 return FALSE;
1926 break;
1927 case bfd_indirect_link_order:
1928 if (! default_indirect_link_order (abfd, info, o, p, TRUE))
1929 return FALSE;
1930 break;
1931 default:
1932 if (! _bfd_default_link_order (abfd, info, o, p))
1933 return FALSE;
1934 break;
1939 return TRUE;
1942 /* Add an output symbol to the output BFD. */
1944 static bfd_boolean
1945 generic_add_output_symbol (bfd *output_bfd, size_t *psymalloc, asymbol *sym)
1947 if (bfd_get_symcount (output_bfd) >= *psymalloc)
1949 asymbol **newsyms;
1950 bfd_size_type amt;
1952 if (*psymalloc == 0)
1953 *psymalloc = 124;
1954 else
1955 *psymalloc *= 2;
1956 amt = *psymalloc;
1957 amt *= sizeof (asymbol *);
1958 newsyms = (asymbol **) bfd_realloc (bfd_get_outsymbols (output_bfd), amt);
1959 if (newsyms == NULL)
1960 return FALSE;
1961 bfd_get_outsymbols (output_bfd) = newsyms;
1964 bfd_get_outsymbols (output_bfd) [bfd_get_symcount (output_bfd)] = sym;
1965 if (sym != NULL)
1966 ++ bfd_get_symcount (output_bfd);
1968 return TRUE;
1971 /* Handle the symbols for an input BFD. */
1973 bfd_boolean
1974 _bfd_generic_link_output_symbols (bfd *output_bfd,
1975 bfd *input_bfd,
1976 struct bfd_link_info *info,
1977 size_t *psymalloc)
1979 asymbol **sym_ptr;
1980 asymbol **sym_end;
1982 if (!bfd_generic_link_read_symbols (input_bfd))
1983 return FALSE;
1985 /* Create a filename symbol if we are supposed to. */
1986 if (info->create_object_symbols_section != NULL)
1988 asection *sec;
1990 for (sec = input_bfd->sections; sec != NULL; sec = sec->next)
1992 if (sec->output_section == info->create_object_symbols_section)
1994 asymbol *newsym;
1996 newsym = bfd_make_empty_symbol (input_bfd);
1997 if (!newsym)
1998 return FALSE;
1999 newsym->name = input_bfd->filename;
2000 newsym->value = 0;
2001 newsym->flags = BSF_LOCAL | BSF_FILE;
2002 newsym->section = sec;
2004 if (! generic_add_output_symbol (output_bfd, psymalloc,
2005 newsym))
2006 return FALSE;
2008 break;
2013 /* Adjust the values of the globally visible symbols, and write out
2014 local symbols. */
2015 sym_ptr = _bfd_generic_link_get_symbols (input_bfd);
2016 sym_end = sym_ptr + _bfd_generic_link_get_symcount (input_bfd);
2017 for (; sym_ptr < sym_end; sym_ptr++)
2019 asymbol *sym;
2020 struct generic_link_hash_entry *h;
2021 bfd_boolean output;
2023 h = NULL;
2024 sym = *sym_ptr;
2025 if ((sym->flags & (BSF_INDIRECT
2026 | BSF_WARNING
2027 | BSF_GLOBAL
2028 | BSF_CONSTRUCTOR
2029 | BSF_WEAK)) != 0
2030 || bfd_is_und_section (bfd_get_section (sym))
2031 || bfd_is_com_section (bfd_get_section (sym))
2032 || bfd_is_ind_section (bfd_get_section (sym)))
2034 if (sym->udata.p != NULL)
2035 h = (struct generic_link_hash_entry *) sym->udata.p;
2036 else if ((sym->flags & BSF_CONSTRUCTOR) != 0)
2038 /* This case normally means that the main linker code
2039 deliberately ignored this constructor symbol. We
2040 should just pass it through. This will screw up if
2041 the constructor symbol is from a different,
2042 non-generic, object file format, but the case will
2043 only arise when linking with -r, which will probably
2044 fail anyhow, since there will be no way to represent
2045 the relocs in the output format being used. */
2046 h = NULL;
2048 else if (bfd_is_und_section (bfd_get_section (sym)))
2049 h = ((struct generic_link_hash_entry *)
2050 bfd_wrapped_link_hash_lookup (output_bfd, info,
2051 bfd_asymbol_name (sym),
2052 FALSE, FALSE, TRUE));
2053 else
2054 h = _bfd_generic_link_hash_lookup (_bfd_generic_hash_table (info),
2055 bfd_asymbol_name (sym),
2056 FALSE, FALSE, TRUE);
2058 if (h != NULL)
2060 /* Force all references to this symbol to point to
2061 the same area in memory. It is possible that
2062 this routine will be called with a hash table
2063 other than a generic hash table, so we double
2064 check that. */
2065 if (info->output_bfd->xvec == input_bfd->xvec)
2067 if (h->sym != NULL)
2068 *sym_ptr = sym = h->sym;
2071 switch (h->root.type)
2073 default:
2074 case bfd_link_hash_new:
2075 abort ();
2076 case bfd_link_hash_undefined:
2077 break;
2078 case bfd_link_hash_undefweak:
2079 sym->flags |= BSF_WEAK;
2080 break;
2081 case bfd_link_hash_indirect:
2082 h = (struct generic_link_hash_entry *) h->root.u.i.link;
2083 /* fall through */
2084 case bfd_link_hash_defined:
2085 sym->flags |= BSF_GLOBAL;
2086 sym->flags &=~ (BSF_WEAK | BSF_CONSTRUCTOR);
2087 sym->value = h->root.u.def.value;
2088 sym->section = h->root.u.def.section;
2089 break;
2090 case bfd_link_hash_defweak:
2091 sym->flags |= BSF_WEAK;
2092 sym->flags &=~ BSF_CONSTRUCTOR;
2093 sym->value = h->root.u.def.value;
2094 sym->section = h->root.u.def.section;
2095 break;
2096 case bfd_link_hash_common:
2097 sym->value = h->root.u.c.size;
2098 sym->flags |= BSF_GLOBAL;
2099 if (! bfd_is_com_section (sym->section))
2101 BFD_ASSERT (bfd_is_und_section (sym->section));
2102 sym->section = bfd_com_section_ptr;
2104 /* We do not set the section of the symbol to
2105 h->root.u.c.p->section. That value was saved so
2106 that we would know where to allocate the symbol
2107 if it was defined. In this case the type is
2108 still bfd_link_hash_common, so we did not define
2109 it, so we do not want to use that section. */
2110 break;
2115 /* This switch is straight from the old code in
2116 write_file_locals in ldsym.c. */
2117 if (info->strip == strip_all
2118 || (info->strip == strip_some
2119 && bfd_hash_lookup (info->keep_hash, bfd_asymbol_name (sym),
2120 FALSE, FALSE) == NULL))
2121 output = FALSE;
2122 else if ((sym->flags & (BSF_GLOBAL | BSF_WEAK | BSF_GNU_UNIQUE)) != 0)
2124 /* If this symbol is marked as occurring now, rather
2125 than at the end, output it now. This is used for
2126 COFF C_EXT FCN symbols. FIXME: There must be a
2127 better way. */
2128 if (bfd_asymbol_bfd (sym) == input_bfd
2129 && (sym->flags & BSF_NOT_AT_END) != 0)
2130 output = TRUE;
2131 else
2132 output = FALSE;
2134 else if (bfd_is_ind_section (sym->section))
2135 output = FALSE;
2136 else if ((sym->flags & BSF_DEBUGGING) != 0)
2138 if (info->strip == strip_none)
2139 output = TRUE;
2140 else
2141 output = FALSE;
2143 else if (bfd_is_und_section (sym->section)
2144 || bfd_is_com_section (sym->section))
2145 output = FALSE;
2146 else if ((sym->flags & BSF_LOCAL) != 0)
2148 if ((sym->flags & BSF_WARNING) != 0)
2149 output = FALSE;
2150 else
2152 switch (info->discard)
2154 default:
2155 case discard_all:
2156 output = FALSE;
2157 break;
2158 case discard_sec_merge:
2159 output = TRUE;
2160 if (bfd_link_relocatable (info)
2161 || ! (sym->section->flags & SEC_MERGE))
2162 break;
2163 /* FALLTHROUGH */
2164 case discard_l:
2165 if (bfd_is_local_label (input_bfd, sym))
2166 output = FALSE;
2167 else
2168 output = TRUE;
2169 break;
2170 case discard_none:
2171 output = TRUE;
2172 break;
2176 else if ((sym->flags & BSF_CONSTRUCTOR))
2178 if (info->strip != strip_all)
2179 output = TRUE;
2180 else
2181 output = FALSE;
2183 else if (sym->flags == 0
2184 && (sym->section->owner->flags & BFD_PLUGIN) != 0)
2185 /* LTO doesn't set symbol information. We get here with the
2186 generic linker for a symbol that was "common" but no longer
2187 needs to be global. */
2188 output = FALSE;
2189 else
2190 abort ();
2192 /* If this symbol is in a section which is not being included
2193 in the output file, then we don't want to output the
2194 symbol. */
2195 if (!bfd_is_abs_section (sym->section)
2196 && bfd_section_removed_from_list (output_bfd,
2197 sym->section->output_section))
2198 output = FALSE;
2200 if (output)
2202 if (! generic_add_output_symbol (output_bfd, psymalloc, sym))
2203 return FALSE;
2204 if (h != NULL)
2205 h->written = TRUE;
2209 return TRUE;
2212 /* Set the section and value of a generic BFD symbol based on a linker
2213 hash table entry. */
2215 static void
2216 set_symbol_from_hash (asymbol *sym, struct bfd_link_hash_entry *h)
2218 switch (h->type)
2220 default:
2221 abort ();
2222 break;
2223 case bfd_link_hash_new:
2224 /* This can happen when a constructor symbol is seen but we are
2225 not building constructors. */
2226 if (sym->section != NULL)
2228 BFD_ASSERT ((sym->flags & BSF_CONSTRUCTOR) != 0);
2230 else
2232 sym->flags |= BSF_CONSTRUCTOR;
2233 sym->section = bfd_abs_section_ptr;
2234 sym->value = 0;
2236 break;
2237 case bfd_link_hash_undefined:
2238 sym->section = bfd_und_section_ptr;
2239 sym->value = 0;
2240 break;
2241 case bfd_link_hash_undefweak:
2242 sym->section = bfd_und_section_ptr;
2243 sym->value = 0;
2244 sym->flags |= BSF_WEAK;
2245 break;
2246 case bfd_link_hash_defined:
2247 sym->section = h->u.def.section;
2248 sym->value = h->u.def.value;
2249 break;
2250 case bfd_link_hash_defweak:
2251 sym->flags |= BSF_WEAK;
2252 sym->section = h->u.def.section;
2253 sym->value = h->u.def.value;
2254 break;
2255 case bfd_link_hash_common:
2256 sym->value = h->u.c.size;
2257 if (sym->section == NULL)
2258 sym->section = bfd_com_section_ptr;
2259 else if (! bfd_is_com_section (sym->section))
2261 BFD_ASSERT (bfd_is_und_section (sym->section));
2262 sym->section = bfd_com_section_ptr;
2264 /* Do not set the section; see _bfd_generic_link_output_symbols. */
2265 break;
2266 case bfd_link_hash_indirect:
2267 case bfd_link_hash_warning:
2268 /* FIXME: What should we do here? */
2269 break;
2273 /* Write out a global symbol, if it hasn't already been written out.
2274 This is called for each symbol in the hash table. */
2276 bfd_boolean
2277 _bfd_generic_link_write_global_symbol (struct generic_link_hash_entry *h,
2278 void *data)
2280 struct generic_write_global_symbol_info *wginfo =
2281 (struct generic_write_global_symbol_info *) data;
2282 asymbol *sym;
2284 if (h->written)
2285 return TRUE;
2287 h->written = TRUE;
2289 if (wginfo->info->strip == strip_all
2290 || (wginfo->info->strip == strip_some
2291 && bfd_hash_lookup (wginfo->info->keep_hash, h->root.root.string,
2292 FALSE, FALSE) == NULL))
2293 return TRUE;
2295 if (h->sym != NULL)
2296 sym = h->sym;
2297 else
2299 sym = bfd_make_empty_symbol (wginfo->output_bfd);
2300 if (!sym)
2301 return FALSE;
2302 sym->name = h->root.root.string;
2303 sym->flags = 0;
2306 set_symbol_from_hash (sym, &h->root);
2308 sym->flags |= BSF_GLOBAL;
2310 if (! generic_add_output_symbol (wginfo->output_bfd, wginfo->psymalloc,
2311 sym))
2313 /* FIXME: No way to return failure. */
2314 abort ();
2317 return TRUE;
2320 /* Create a relocation. */
2322 bfd_boolean
2323 _bfd_generic_reloc_link_order (bfd *abfd,
2324 struct bfd_link_info *info,
2325 asection *sec,
2326 struct bfd_link_order *link_order)
2328 arelent *r;
2330 if (! bfd_link_relocatable (info))
2331 abort ();
2332 if (sec->orelocation == NULL)
2333 abort ();
2335 r = (arelent *) bfd_alloc (abfd, sizeof (arelent));
2336 if (r == NULL)
2337 return FALSE;
2339 r->address = link_order->offset;
2340 r->howto = bfd_reloc_type_lookup (abfd, link_order->u.reloc.p->reloc);
2341 if (r->howto == 0)
2343 bfd_set_error (bfd_error_bad_value);
2344 return FALSE;
2347 /* Get the symbol to use for the relocation. */
2348 if (link_order->type == bfd_section_reloc_link_order)
2349 r->sym_ptr_ptr = link_order->u.reloc.p->u.section->symbol_ptr_ptr;
2350 else
2352 struct generic_link_hash_entry *h;
2354 h = ((struct generic_link_hash_entry *)
2355 bfd_wrapped_link_hash_lookup (abfd, info,
2356 link_order->u.reloc.p->u.name,
2357 FALSE, FALSE, TRUE));
2358 if (h == NULL
2359 || ! h->written)
2361 (*info->callbacks->unattached_reloc)
2362 (info, link_order->u.reloc.p->u.name, NULL, NULL, 0);
2363 bfd_set_error (bfd_error_bad_value);
2364 return FALSE;
2366 r->sym_ptr_ptr = &h->sym;
2369 /* If this is an inplace reloc, write the addend to the object file.
2370 Otherwise, store it in the reloc addend. */
2371 if (! r->howto->partial_inplace)
2372 r->addend = link_order->u.reloc.p->addend;
2373 else
2375 bfd_size_type size;
2376 bfd_reloc_status_type rstat;
2377 bfd_byte *buf;
2378 bfd_boolean ok;
2379 file_ptr loc;
2381 size = bfd_get_reloc_size (r->howto);
2382 buf = (bfd_byte *) bfd_zmalloc (size);
2383 if (buf == NULL && size != 0)
2384 return FALSE;
2385 rstat = _bfd_relocate_contents (r->howto, abfd,
2386 (bfd_vma) link_order->u.reloc.p->addend,
2387 buf);
2388 switch (rstat)
2390 case bfd_reloc_ok:
2391 break;
2392 default:
2393 case bfd_reloc_outofrange:
2394 abort ();
2395 case bfd_reloc_overflow:
2396 (*info->callbacks->reloc_overflow)
2397 (info, NULL,
2398 (link_order->type == bfd_section_reloc_link_order
2399 ? bfd_section_name (abfd, link_order->u.reloc.p->u.section)
2400 : link_order->u.reloc.p->u.name),
2401 r->howto->name, link_order->u.reloc.p->addend,
2402 NULL, NULL, 0);
2403 break;
2405 loc = link_order->offset * bfd_octets_per_byte (abfd);
2406 ok = bfd_set_section_contents (abfd, sec, buf, loc, size);
2407 free (buf);
2408 if (! ok)
2409 return FALSE;
2411 r->addend = 0;
2414 sec->orelocation[sec->reloc_count] = r;
2415 ++sec->reloc_count;
2417 return TRUE;
2420 /* Allocate a new link_order for a section. */
2422 struct bfd_link_order *
2423 bfd_new_link_order (bfd *abfd, asection *section)
2425 bfd_size_type amt = sizeof (struct bfd_link_order);
2426 struct bfd_link_order *new_lo;
2428 new_lo = (struct bfd_link_order *) bfd_zalloc (abfd, amt);
2429 if (!new_lo)
2430 return NULL;
2432 new_lo->type = bfd_undefined_link_order;
2434 if (section->map_tail.link_order != NULL)
2435 section->map_tail.link_order->next = new_lo;
2436 else
2437 section->map_head.link_order = new_lo;
2438 section->map_tail.link_order = new_lo;
2440 return new_lo;
2443 /* Default link order processing routine. Note that we can not handle
2444 the reloc_link_order types here, since they depend upon the details
2445 of how the particular backends generates relocs. */
2447 bfd_boolean
2448 _bfd_default_link_order (bfd *abfd,
2449 struct bfd_link_info *info,
2450 asection *sec,
2451 struct bfd_link_order *link_order)
2453 switch (link_order->type)
2455 case bfd_undefined_link_order:
2456 case bfd_section_reloc_link_order:
2457 case bfd_symbol_reloc_link_order:
2458 default:
2459 abort ();
2460 case bfd_indirect_link_order:
2461 return default_indirect_link_order (abfd, info, sec, link_order,
2462 FALSE);
2463 case bfd_data_link_order:
2464 return default_data_link_order (abfd, info, sec, link_order);
2468 /* Default routine to handle a bfd_data_link_order. */
2470 static bfd_boolean
2471 default_data_link_order (bfd *abfd,
2472 struct bfd_link_info *info ATTRIBUTE_UNUSED,
2473 asection *sec,
2474 struct bfd_link_order *link_order)
2476 bfd_size_type size;
2477 size_t fill_size;
2478 bfd_byte *fill;
2479 file_ptr loc;
2480 bfd_boolean result;
2482 BFD_ASSERT ((sec->flags & SEC_HAS_CONTENTS) != 0);
2484 size = link_order->size;
2485 if (size == 0)
2486 return TRUE;
2488 fill = link_order->u.data.contents;
2489 fill_size = link_order->u.data.size;
2490 if (fill_size == 0)
2492 fill = abfd->arch_info->fill (size, bfd_big_endian (abfd),
2493 (sec->flags & SEC_CODE) != 0);
2494 if (fill == NULL)
2495 return FALSE;
2497 else if (fill_size < size)
2499 bfd_byte *p;
2500 fill = (bfd_byte *) bfd_malloc (size);
2501 if (fill == NULL)
2502 return FALSE;
2503 p = fill;
2504 if (fill_size == 1)
2505 memset (p, (int) link_order->u.data.contents[0], (size_t) size);
2506 else
2510 memcpy (p, link_order->u.data.contents, fill_size);
2511 p += fill_size;
2512 size -= fill_size;
2514 while (size >= fill_size);
2515 if (size != 0)
2516 memcpy (p, link_order->u.data.contents, (size_t) size);
2517 size = link_order->size;
2521 loc = link_order->offset * bfd_octets_per_byte (abfd);
2522 result = bfd_set_section_contents (abfd, sec, fill, loc, size);
2524 if (fill != link_order->u.data.contents)
2525 free (fill);
2526 return result;
2529 /* Default routine to handle a bfd_indirect_link_order. */
2531 static bfd_boolean
2532 default_indirect_link_order (bfd *output_bfd,
2533 struct bfd_link_info *info,
2534 asection *output_section,
2535 struct bfd_link_order *link_order,
2536 bfd_boolean generic_linker)
2538 asection *input_section;
2539 bfd *input_bfd;
2540 bfd_byte *contents = NULL;
2541 bfd_byte *new_contents;
2542 bfd_size_type sec_size;
2543 file_ptr loc;
2545 BFD_ASSERT ((output_section->flags & SEC_HAS_CONTENTS) != 0);
2547 input_section = link_order->u.indirect.section;
2548 input_bfd = input_section->owner;
2549 if (input_section->size == 0)
2550 return TRUE;
2552 BFD_ASSERT (input_section->output_section == output_section);
2553 BFD_ASSERT (input_section->output_offset == link_order->offset);
2554 BFD_ASSERT (input_section->size == link_order->size);
2556 if (bfd_link_relocatable (info)
2557 && input_section->reloc_count > 0
2558 && output_section->orelocation == NULL)
2560 /* Space has not been allocated for the output relocations.
2561 This can happen when we are called by a specific backend
2562 because somebody is attempting to link together different
2563 types of object files. Handling this case correctly is
2564 difficult, and sometimes impossible. */
2565 _bfd_error_handler
2566 /* xgettext:c-format */
2567 (_("attempt to do relocatable link with %s input and %s output"),
2568 bfd_get_target (input_bfd), bfd_get_target (output_bfd));
2569 bfd_set_error (bfd_error_wrong_format);
2570 return FALSE;
2573 if (! generic_linker)
2575 asymbol **sympp;
2576 asymbol **symppend;
2578 /* Get the canonical symbols. The generic linker will always
2579 have retrieved them by this point, but we are being called by
2580 a specific linker, presumably because we are linking
2581 different types of object files together. */
2582 if (!bfd_generic_link_read_symbols (input_bfd))
2583 return FALSE;
2585 /* Since we have been called by a specific linker, rather than
2586 the generic linker, the values of the symbols will not be
2587 right. They will be the values as seen in the input file,
2588 not the values of the final link. We need to fix them up
2589 before we can relocate the section. */
2590 sympp = _bfd_generic_link_get_symbols (input_bfd);
2591 symppend = sympp + _bfd_generic_link_get_symcount (input_bfd);
2592 for (; sympp < symppend; sympp++)
2594 asymbol *sym;
2595 struct bfd_link_hash_entry *h;
2597 sym = *sympp;
2599 if ((sym->flags & (BSF_INDIRECT
2600 | BSF_WARNING
2601 | BSF_GLOBAL
2602 | BSF_CONSTRUCTOR
2603 | BSF_WEAK)) != 0
2604 || bfd_is_und_section (bfd_get_section (sym))
2605 || bfd_is_com_section (bfd_get_section (sym))
2606 || bfd_is_ind_section (bfd_get_section (sym)))
2608 /* sym->udata may have been set by
2609 generic_link_add_symbol_list. */
2610 if (sym->udata.p != NULL)
2611 h = (struct bfd_link_hash_entry *) sym->udata.p;
2612 else if (bfd_is_und_section (bfd_get_section (sym)))
2613 h = bfd_wrapped_link_hash_lookup (output_bfd, info,
2614 bfd_asymbol_name (sym),
2615 FALSE, FALSE, TRUE);
2616 else
2617 h = bfd_link_hash_lookup (info->hash,
2618 bfd_asymbol_name (sym),
2619 FALSE, FALSE, TRUE);
2620 if (h != NULL)
2621 set_symbol_from_hash (sym, h);
2626 if ((output_section->flags & (SEC_GROUP | SEC_LINKER_CREATED)) == SEC_GROUP
2627 && input_section->size != 0)
2629 /* Group section contents are set by bfd_elf_set_group_contents. */
2630 if (!output_bfd->output_has_begun)
2632 /* FIXME: This hack ensures bfd_elf_set_group_contents is called. */
2633 if (!bfd_set_section_contents (output_bfd, output_section, "", 0, 1))
2634 goto error_return;
2636 new_contents = output_section->contents;
2637 BFD_ASSERT (new_contents != NULL);
2638 BFD_ASSERT (input_section->output_offset == 0);
2640 else
2642 /* Get and relocate the section contents. */
2643 sec_size = (input_section->rawsize > input_section->size
2644 ? input_section->rawsize
2645 : input_section->size);
2646 contents = (bfd_byte *) bfd_malloc (sec_size);
2647 if (contents == NULL && sec_size != 0)
2648 goto error_return;
2649 new_contents = (bfd_get_relocated_section_contents
2650 (output_bfd, info, link_order, contents,
2651 bfd_link_relocatable (info),
2652 _bfd_generic_link_get_symbols (input_bfd)));
2653 if (!new_contents)
2654 goto error_return;
2657 /* Output the section contents. */
2658 loc = input_section->output_offset * bfd_octets_per_byte (output_bfd);
2659 if (! bfd_set_section_contents (output_bfd, output_section,
2660 new_contents, loc, input_section->size))
2661 goto error_return;
2663 if (contents != NULL)
2664 free (contents);
2665 return TRUE;
2667 error_return:
2668 if (contents != NULL)
2669 free (contents);
2670 return FALSE;
2673 /* A little routine to count the number of relocs in a link_order
2674 list. */
2676 unsigned int
2677 _bfd_count_link_order_relocs (struct bfd_link_order *link_order)
2679 register unsigned int c;
2680 register struct bfd_link_order *l;
2682 c = 0;
2683 for (l = link_order; l != NULL; l = l->next)
2685 if (l->type == bfd_section_reloc_link_order
2686 || l->type == bfd_symbol_reloc_link_order)
2687 ++c;
2690 return c;
2694 FUNCTION
2695 bfd_link_split_section
2697 SYNOPSIS
2698 bfd_boolean bfd_link_split_section (bfd *abfd, asection *sec);
2700 DESCRIPTION
2701 Return nonzero if @var{sec} should be split during a
2702 reloceatable or final link.
2704 .#define bfd_link_split_section(abfd, sec) \
2705 . BFD_SEND (abfd, _bfd_link_split_section, (abfd, sec))
2710 bfd_boolean
2711 _bfd_generic_link_split_section (bfd *abfd ATTRIBUTE_UNUSED,
2712 asection *sec ATTRIBUTE_UNUSED)
2714 return FALSE;
2718 FUNCTION
2719 bfd_section_already_linked
2721 SYNOPSIS
2722 bfd_boolean bfd_section_already_linked (bfd *abfd,
2723 asection *sec,
2724 struct bfd_link_info *info);
2726 DESCRIPTION
2727 Check if @var{data} has been already linked during a reloceatable
2728 or final link. Return TRUE if it has.
2730 .#define bfd_section_already_linked(abfd, sec, info) \
2731 . BFD_SEND (abfd, _section_already_linked, (abfd, sec, info))
2736 /* Sections marked with the SEC_LINK_ONCE flag should only be linked
2737 once into the output. This routine checks each section, and
2738 arrange to discard it if a section of the same name has already
2739 been linked. This code assumes that all relevant sections have the
2740 SEC_LINK_ONCE flag set; that is, it does not depend solely upon the
2741 section name. bfd_section_already_linked is called via
2742 bfd_map_over_sections. */
2744 /* The hash table. */
2746 static struct bfd_hash_table _bfd_section_already_linked_table;
2748 /* Support routines for the hash table used by section_already_linked,
2749 initialize the table, traverse, lookup, fill in an entry and remove
2750 the table. */
2752 void
2753 bfd_section_already_linked_table_traverse
2754 (bfd_boolean (*func) (struct bfd_section_already_linked_hash_entry *,
2755 void *), void *info)
2757 bfd_hash_traverse (&_bfd_section_already_linked_table,
2758 (bfd_boolean (*) (struct bfd_hash_entry *,
2759 void *)) func,
2760 info);
2763 struct bfd_section_already_linked_hash_entry *
2764 bfd_section_already_linked_table_lookup (const char *name)
2766 return ((struct bfd_section_already_linked_hash_entry *)
2767 bfd_hash_lookup (&_bfd_section_already_linked_table, name,
2768 TRUE, FALSE));
2771 bfd_boolean
2772 bfd_section_already_linked_table_insert
2773 (struct bfd_section_already_linked_hash_entry *already_linked_list,
2774 asection *sec)
2776 struct bfd_section_already_linked *l;
2778 /* Allocate the memory from the same obstack as the hash table is
2779 kept in. */
2780 l = (struct bfd_section_already_linked *)
2781 bfd_hash_allocate (&_bfd_section_already_linked_table, sizeof *l);
2782 if (l == NULL)
2783 return FALSE;
2784 l->sec = sec;
2785 l->next = already_linked_list->entry;
2786 already_linked_list->entry = l;
2787 return TRUE;
2790 static struct bfd_hash_entry *
2791 already_linked_newfunc (struct bfd_hash_entry *entry ATTRIBUTE_UNUSED,
2792 struct bfd_hash_table *table,
2793 const char *string ATTRIBUTE_UNUSED)
2795 struct bfd_section_already_linked_hash_entry *ret =
2796 (struct bfd_section_already_linked_hash_entry *)
2797 bfd_hash_allocate (table, sizeof *ret);
2799 if (ret == NULL)
2800 return NULL;
2802 ret->entry = NULL;
2804 return &ret->root;
2807 bfd_boolean
2808 bfd_section_already_linked_table_init (void)
2810 return bfd_hash_table_init_n (&_bfd_section_already_linked_table,
2811 already_linked_newfunc,
2812 sizeof (struct bfd_section_already_linked_hash_entry),
2813 42);
2816 void
2817 bfd_section_already_linked_table_free (void)
2819 bfd_hash_table_free (&_bfd_section_already_linked_table);
2822 /* Report warnings as appropriate for duplicate section SEC.
2823 Return FALSE if we decide to keep SEC after all. */
2825 bfd_boolean
2826 _bfd_handle_already_linked (asection *sec,
2827 struct bfd_section_already_linked *l,
2828 struct bfd_link_info *info)
2830 switch (sec->flags & SEC_LINK_DUPLICATES)
2832 default:
2833 abort ();
2835 case SEC_LINK_DUPLICATES_DISCARD:
2836 /* If we found an LTO IR match for this comdat group on
2837 the first pass, replace it with the LTO output on the
2838 second pass. We can't simply choose real object
2839 files over IR because the first pass may contain a
2840 mix of LTO and normal objects and we must keep the
2841 first match, be it IR or real. */
2842 if (sec->owner->lto_output
2843 && (l->sec->owner->flags & BFD_PLUGIN) != 0)
2845 l->sec = sec;
2846 return FALSE;
2848 break;
2850 case SEC_LINK_DUPLICATES_ONE_ONLY:
2851 info->callbacks->einfo
2852 /* xgettext:c-format */
2853 (_("%pB: ignoring duplicate section `%pA'\n"),
2854 sec->owner, sec);
2855 break;
2857 case SEC_LINK_DUPLICATES_SAME_SIZE:
2858 if ((l->sec->owner->flags & BFD_PLUGIN) != 0)
2860 else if (sec->size != l->sec->size)
2861 info->callbacks->einfo
2862 /* xgettext:c-format */
2863 (_("%pB: duplicate section `%pA' has different size\n"),
2864 sec->owner, sec);
2865 break;
2867 case SEC_LINK_DUPLICATES_SAME_CONTENTS:
2868 if ((l->sec->owner->flags & BFD_PLUGIN) != 0)
2870 else if (sec->size != l->sec->size)
2871 info->callbacks->einfo
2872 /* xgettext:c-format */
2873 (_("%pB: duplicate section `%pA' has different size\n"),
2874 sec->owner, sec);
2875 else if (sec->size != 0)
2877 bfd_byte *sec_contents, *l_sec_contents = NULL;
2879 if (!bfd_malloc_and_get_section (sec->owner, sec, &sec_contents))
2880 info->callbacks->einfo
2881 /* xgettext:c-format */
2882 (_("%pB: could not read contents of section `%pA'\n"),
2883 sec->owner, sec);
2884 else if (!bfd_malloc_and_get_section (l->sec->owner, l->sec,
2885 &l_sec_contents))
2886 info->callbacks->einfo
2887 /* xgettext:c-format */
2888 (_("%pB: could not read contents of section `%pA'\n"),
2889 l->sec->owner, l->sec);
2890 else if (memcmp (sec_contents, l_sec_contents, sec->size) != 0)
2891 info->callbacks->einfo
2892 /* xgettext:c-format */
2893 (_("%pB: duplicate section `%pA' has different contents\n"),
2894 sec->owner, sec);
2896 if (sec_contents)
2897 free (sec_contents);
2898 if (l_sec_contents)
2899 free (l_sec_contents);
2901 break;
2904 /* Set the output_section field so that lang_add_section
2905 does not create a lang_input_section structure for this
2906 section. Since there might be a symbol in the section
2907 being discarded, we must retain a pointer to the section
2908 which we are really going to use. */
2909 sec->output_section = bfd_abs_section_ptr;
2910 sec->kept_section = l->sec;
2911 return TRUE;
2914 /* This is used on non-ELF inputs. */
2916 bfd_boolean
2917 _bfd_generic_section_already_linked (bfd *abfd ATTRIBUTE_UNUSED,
2918 asection *sec,
2919 struct bfd_link_info *info)
2921 const char *name;
2922 struct bfd_section_already_linked *l;
2923 struct bfd_section_already_linked_hash_entry *already_linked_list;
2925 if ((sec->flags & SEC_LINK_ONCE) == 0)
2926 return FALSE;
2928 /* The generic linker doesn't handle section groups. */
2929 if ((sec->flags & SEC_GROUP) != 0)
2930 return FALSE;
2932 /* FIXME: When doing a relocatable link, we may have trouble
2933 copying relocations in other sections that refer to local symbols
2934 in the section being discarded. Those relocations will have to
2935 be converted somehow; as of this writing I'm not sure that any of
2936 the backends handle that correctly.
2938 It is tempting to instead not discard link once sections when
2939 doing a relocatable link (technically, they should be discarded
2940 whenever we are building constructors). However, that fails,
2941 because the linker winds up combining all the link once sections
2942 into a single large link once section, which defeats the purpose
2943 of having link once sections in the first place. */
2945 name = bfd_get_section_name (abfd, sec);
2947 already_linked_list = bfd_section_already_linked_table_lookup (name);
2949 l = already_linked_list->entry;
2950 if (l != NULL)
2952 /* The section has already been linked. See if we should
2953 issue a warning. */
2954 return _bfd_handle_already_linked (sec, l, info);
2957 /* This is the first section with this name. Record it. */
2958 if (!bfd_section_already_linked_table_insert (already_linked_list, sec))
2959 info->callbacks->einfo (_("%F%P: already_linked_table: %E\n"));
2960 return FALSE;
2963 /* Choose a neighbouring section to S in OBFD that will be output, or
2964 the absolute section if ADDR is out of bounds of the neighbours. */
2966 asection *
2967 _bfd_nearby_section (bfd *obfd, asection *s, bfd_vma addr)
2969 asection *next, *prev, *best;
2971 /* Find preceding kept section. */
2972 for (prev = s->prev; prev != NULL; prev = prev->prev)
2973 if ((prev->flags & SEC_EXCLUDE) == 0
2974 && !bfd_section_removed_from_list (obfd, prev))
2975 break;
2977 /* Find following kept section. Start at prev->next because
2978 other sections may have been added after S was removed. */
2979 if (s->prev != NULL)
2980 next = s->prev->next;
2981 else
2982 next = s->owner->sections;
2983 for (; next != NULL; next = next->next)
2984 if ((next->flags & SEC_EXCLUDE) == 0
2985 && !bfd_section_removed_from_list (obfd, next))
2986 break;
2988 /* Choose better of two sections, based on flags. The idea
2989 is to choose a section that will be in the same segment
2990 as S would have been if it was kept. */
2991 best = next;
2992 if (prev == NULL)
2994 if (next == NULL)
2995 best = bfd_abs_section_ptr;
2997 else if (next == NULL)
2998 best = prev;
2999 else if (((prev->flags ^ next->flags)
3000 & (SEC_ALLOC | SEC_THREAD_LOCAL | SEC_LOAD)) != 0)
3002 if (((next->flags ^ s->flags)
3003 & (SEC_ALLOC | SEC_THREAD_LOCAL)) != 0
3004 /* We prefer to choose a loaded section. Section S
3005 doesn't have SEC_LOAD set (it being excluded, that
3006 part of the flag processing didn't happen) so we
3007 can't compare that flag to those of NEXT and PREV. */
3008 || ((prev->flags & SEC_LOAD) != 0
3009 && (next->flags & SEC_LOAD) == 0))
3010 best = prev;
3012 else if (((prev->flags ^ next->flags) & SEC_READONLY) != 0)
3014 if (((next->flags ^ s->flags) & SEC_READONLY) != 0)
3015 best = prev;
3017 else if (((prev->flags ^ next->flags) & SEC_CODE) != 0)
3019 if (((next->flags ^ s->flags) & SEC_CODE) != 0)
3020 best = prev;
3022 else
3024 /* Flags we care about are the same. Prefer the following
3025 section if that will result in a positive valued sym. */
3026 if (addr < next->vma)
3027 best = prev;
3030 return best;
3033 /* Convert symbols in excluded output sections to use a kept section. */
3035 static bfd_boolean
3036 fix_syms (struct bfd_link_hash_entry *h, void *data)
3038 bfd *obfd = (bfd *) data;
3040 if (h->type == bfd_link_hash_defined
3041 || h->type == bfd_link_hash_defweak)
3043 asection *s = h->u.def.section;
3044 if (s != NULL
3045 && s->output_section != NULL
3046 && (s->output_section->flags & SEC_EXCLUDE) != 0
3047 && bfd_section_removed_from_list (obfd, s->output_section))
3049 asection *op;
3051 h->u.def.value += s->output_offset + s->output_section->vma;
3052 op = _bfd_nearby_section (obfd, s->output_section, h->u.def.value);
3053 h->u.def.value -= op->vma;
3054 h->u.def.section = op;
3058 return TRUE;
3061 void
3062 _bfd_fix_excluded_sec_syms (bfd *obfd, struct bfd_link_info *info)
3064 bfd_link_hash_traverse (info->hash, fix_syms, obfd);
3068 FUNCTION
3069 bfd_generic_define_common_symbol
3071 SYNOPSIS
3072 bfd_boolean bfd_generic_define_common_symbol
3073 (bfd *output_bfd, struct bfd_link_info *info,
3074 struct bfd_link_hash_entry *h);
3076 DESCRIPTION
3077 Convert common symbol @var{h} into a defined symbol.
3078 Return TRUE on success and FALSE on failure.
3080 .#define bfd_define_common_symbol(output_bfd, info, h) \
3081 . BFD_SEND (output_bfd, _bfd_define_common_symbol, (output_bfd, info, h))
3085 bfd_boolean
3086 bfd_generic_define_common_symbol (bfd *output_bfd,
3087 struct bfd_link_info *info ATTRIBUTE_UNUSED,
3088 struct bfd_link_hash_entry *h)
3090 unsigned int power_of_two;
3091 bfd_vma alignment, size;
3092 asection *section;
3094 BFD_ASSERT (h != NULL && h->type == bfd_link_hash_common);
3096 size = h->u.c.size;
3097 power_of_two = h->u.c.p->alignment_power;
3098 section = h->u.c.p->section;
3100 /* Increase the size of the section to align the common symbol.
3101 The alignment must be a power of two. */
3102 alignment = bfd_octets_per_byte (output_bfd) << power_of_two;
3103 BFD_ASSERT (alignment != 0 && (alignment & -alignment) == alignment);
3104 section->size += alignment - 1;
3105 section->size &= -alignment;
3107 /* Adjust the section's overall alignment if necessary. */
3108 if (power_of_two > section->alignment_power)
3109 section->alignment_power = power_of_two;
3111 /* Change the symbol from common to defined. */
3112 h->type = bfd_link_hash_defined;
3113 h->u.def.section = section;
3114 h->u.def.value = section->size;
3116 /* Increase the size of the section. */
3117 section->size += size;
3119 /* Make sure the section is allocated in memory, and make sure that
3120 it is no longer a common section. */
3121 section->flags |= SEC_ALLOC;
3122 section->flags &= ~(SEC_IS_COMMON | SEC_HAS_CONTENTS);
3123 return TRUE;
3127 FUNCTION
3128 _bfd_generic_link_hide_symbol
3130 SYNOPSIS
3131 void _bfd_generic_link_hide_symbol
3132 (bfd *output_bfd, struct bfd_link_info *info,
3133 struct bfd_link_hash_entry *h);
3135 DESCRIPTION
3136 Hide symbol @var{h}.
3137 This is an internal function. It should not be called from
3138 outside the BFD library.
3140 .#define bfd_link_hide_symbol(output_bfd, info, h) \
3141 . BFD_SEND (output_bfd, _bfd_link_hide_symbol, (output_bfd, info, h))
3145 void
3146 _bfd_generic_link_hide_symbol (bfd *output_bfd ATTRIBUTE_UNUSED,
3147 struct bfd_link_info *info ATTRIBUTE_UNUSED,
3148 struct bfd_link_hash_entry *h ATTRIBUTE_UNUSED)
3153 FUNCTION
3154 bfd_generic_define_start_stop
3156 SYNOPSIS
3157 struct bfd_link_hash_entry *bfd_generic_define_start_stop
3158 (struct bfd_link_info *info,
3159 const char *symbol, asection *sec);
3161 DESCRIPTION
3162 Define a __start, __stop, .startof. or .sizeof. symbol.
3163 Return the symbol or NULL if no such undefined symbol exists.
3165 .#define bfd_define_start_stop(output_bfd, info, symbol, sec) \
3166 . BFD_SEND (output_bfd, _bfd_define_start_stop, (info, symbol, sec))
3170 struct bfd_link_hash_entry *
3171 bfd_generic_define_start_stop (struct bfd_link_info *info,
3172 const char *symbol, asection *sec)
3174 struct bfd_link_hash_entry *h;
3176 h = bfd_link_hash_lookup (info->hash, symbol, FALSE, FALSE, TRUE);
3177 if (h != NULL
3178 && (h->type == bfd_link_hash_undefined
3179 || h->type == bfd_link_hash_undefweak))
3181 h->type = bfd_link_hash_defined;
3182 h->u.def.section = sec;
3183 h->u.def.value = 0;
3184 return h;
3186 return NULL;
3190 FUNCTION
3191 bfd_find_version_for_sym
3193 SYNOPSIS
3194 struct bfd_elf_version_tree * bfd_find_version_for_sym
3195 (struct bfd_elf_version_tree *verdefs,
3196 const char *sym_name, bfd_boolean *hide);
3198 DESCRIPTION
3199 Search an elf version script tree for symbol versioning
3200 info and export / don't-export status for a given symbol.
3201 Return non-NULL on success and NULL on failure; also sets
3202 the output @samp{hide} boolean parameter.
3206 struct bfd_elf_version_tree *
3207 bfd_find_version_for_sym (struct bfd_elf_version_tree *verdefs,
3208 const char *sym_name,
3209 bfd_boolean *hide)
3211 struct bfd_elf_version_tree *t;
3212 struct bfd_elf_version_tree *local_ver, *global_ver, *exist_ver;
3213 struct bfd_elf_version_tree *star_local_ver, *star_global_ver;
3215 local_ver = NULL;
3216 global_ver = NULL;
3217 star_local_ver = NULL;
3218 star_global_ver = NULL;
3219 exist_ver = NULL;
3220 for (t = verdefs; t != NULL; t = t->next)
3222 if (t->globals.list != NULL)
3224 struct bfd_elf_version_expr *d = NULL;
3226 while ((d = (*t->match) (&t->globals, d, sym_name)) != NULL)
3228 if (d->literal || strcmp (d->pattern, "*") != 0)
3229 global_ver = t;
3230 else
3231 star_global_ver = t;
3232 if (d->symver)
3233 exist_ver = t;
3234 d->script = 1;
3235 /* If the match is a wildcard pattern, keep looking for
3236 a more explicit, perhaps even local, match. */
3237 if (d->literal)
3238 break;
3241 if (d != NULL)
3242 break;
3245 if (t->locals.list != NULL)
3247 struct bfd_elf_version_expr *d = NULL;
3249 while ((d = (*t->match) (&t->locals, d, sym_name)) != NULL)
3251 if (d->literal || strcmp (d->pattern, "*") != 0)
3252 local_ver = t;
3253 else
3254 star_local_ver = t;
3255 /* If the match is a wildcard pattern, keep looking for
3256 a more explicit, perhaps even global, match. */
3257 if (d->literal)
3259 /* An exact match overrides a global wildcard. */
3260 global_ver = NULL;
3261 star_global_ver = NULL;
3262 break;
3266 if (d != NULL)
3267 break;
3271 if (global_ver == NULL && local_ver == NULL)
3272 global_ver = star_global_ver;
3274 if (global_ver != NULL)
3276 /* If we already have a versioned symbol that matches the
3277 node for this symbol, then we don't want to create a
3278 duplicate from the unversioned symbol. Instead hide the
3279 unversioned symbol. */
3280 *hide = exist_ver == global_ver;
3281 return global_ver;
3284 if (local_ver == NULL)
3285 local_ver = star_local_ver;
3287 if (local_ver != NULL)
3289 *hide = TRUE;
3290 return local_ver;
3293 return NULL;
3297 FUNCTION
3298 bfd_hide_sym_by_version
3300 SYNOPSIS
3301 bfd_boolean bfd_hide_sym_by_version
3302 (struct bfd_elf_version_tree *verdefs, const char *sym_name);
3304 DESCRIPTION
3305 Search an elf version script tree for symbol versioning
3306 info for a given symbol. Return TRUE if the symbol is hidden.
3310 bfd_boolean
3311 bfd_hide_sym_by_version (struct bfd_elf_version_tree *verdefs,
3312 const char *sym_name)
3314 bfd_boolean hidden = FALSE;
3315 bfd_find_version_for_sym (verdefs, sym_name, &hidden);
3316 return hidden;
3320 FUNCTION
3321 bfd_link_check_relocs
3323 SYNOPSIS
3324 bfd_boolean bfd_link_check_relocs
3325 (bfd *abfd, struct bfd_link_info *info);
3327 DESCRIPTION
3328 Checks the relocs in ABFD for validity.
3329 Does not execute the relocs.
3330 Return TRUE if everything is OK, FALSE otherwise.
3331 This is the external entry point to this code.
3334 bfd_boolean
3335 bfd_link_check_relocs (bfd *abfd, struct bfd_link_info *info)
3337 return BFD_SEND (abfd, _bfd_link_check_relocs, (abfd, info));
3341 FUNCTION
3342 _bfd_generic_link_check_relocs
3344 SYNOPSIS
3345 bfd_boolean _bfd_generic_link_check_relocs
3346 (bfd *abfd, struct bfd_link_info *info);
3348 DESCRIPTION
3349 Stub function for targets that do not implement reloc checking.
3350 Return TRUE.
3351 This is an internal function. It should not be called from
3352 outside the BFD library.
3355 bfd_boolean
3356 _bfd_generic_link_check_relocs (bfd *abfd ATTRIBUTE_UNUSED,
3357 struct bfd_link_info *info ATTRIBUTE_UNUSED)
3359 return TRUE;
3363 FUNCTION
3364 bfd_merge_private_bfd_data
3366 SYNOPSIS
3367 bfd_boolean bfd_merge_private_bfd_data
3368 (bfd *ibfd, struct bfd_link_info *info);
3370 DESCRIPTION
3371 Merge private BFD information from the BFD @var{ibfd} to the
3372 the output file BFD when linking. Return <<TRUE>> on success,
3373 <<FALSE>> on error. Possible error returns are:
3375 o <<bfd_error_no_memory>> -
3376 Not enough memory exists to create private data for @var{obfd}.
3378 .#define bfd_merge_private_bfd_data(ibfd, info) \
3379 . BFD_SEND ((info)->output_bfd, _bfd_merge_private_bfd_data, \
3380 . (ibfd, info))
3384 INTERNAL_FUNCTION
3385 _bfd_generic_verify_endian_match
3387 SYNOPSIS
3388 bfd_boolean _bfd_generic_verify_endian_match
3389 (bfd *ibfd, struct bfd_link_info *info);
3391 DESCRIPTION
3392 Can be used from / for bfd_merge_private_bfd_data to check that
3393 endianness matches between input and output file. Returns
3394 TRUE for a match, otherwise returns FALSE and emits an error.
3397 bfd_boolean
3398 _bfd_generic_verify_endian_match (bfd *ibfd, struct bfd_link_info *info)
3400 bfd *obfd = info->output_bfd;
3402 if (ibfd->xvec->byteorder != obfd->xvec->byteorder
3403 && ibfd->xvec->byteorder != BFD_ENDIAN_UNKNOWN
3404 && obfd->xvec->byteorder != BFD_ENDIAN_UNKNOWN)
3406 if (bfd_big_endian (ibfd))
3407 _bfd_error_handler (_("%pB: compiled for a big endian system "
3408 "and target is little endian"), ibfd);
3409 else
3410 _bfd_error_handler (_("%pB: compiled for a little endian system "
3411 "and target is big endian"), ibfd);
3412 bfd_set_error (bfd_error_wrong_format);
3413 return FALSE;
3416 return TRUE;
3420 _bfd_nolink_sizeof_headers (bfd *abfd ATTRIBUTE_UNUSED,
3421 struct bfd_link_info *info ATTRIBUTE_UNUSED)
3423 return 0;
3426 bfd_boolean
3427 _bfd_nolink_bfd_relax_section (bfd *abfd,
3428 asection *section ATTRIBUTE_UNUSED,
3429 struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
3430 bfd_boolean *again ATTRIBUTE_UNUSED)
3432 return _bfd_bool_bfd_false_error (abfd);
3435 bfd_byte *
3436 _bfd_nolink_bfd_get_relocated_section_contents
3437 (bfd *abfd,
3438 struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
3439 struct bfd_link_order *link_order ATTRIBUTE_UNUSED,
3440 bfd_byte *data ATTRIBUTE_UNUSED,
3441 bfd_boolean relocatable ATTRIBUTE_UNUSED,
3442 asymbol **symbols ATTRIBUTE_UNUSED)
3444 return (bfd_byte *) _bfd_ptr_bfd_null_error (abfd);
3447 bfd_boolean
3448 _bfd_nolink_bfd_lookup_section_flags
3449 (struct bfd_link_info *info ATTRIBUTE_UNUSED,
3450 struct flag_info *flaginfo ATTRIBUTE_UNUSED,
3451 asection *section)
3453 return _bfd_bool_bfd_false_error (section->owner);
3456 bfd_boolean
3457 _bfd_nolink_bfd_is_group_section (bfd *abfd,
3458 const asection *sec ATTRIBUTE_UNUSED)
3460 return _bfd_bool_bfd_false_error (abfd);
3463 bfd_boolean
3464 _bfd_nolink_bfd_discard_group (bfd *abfd, asection *sec ATTRIBUTE_UNUSED)
3466 return _bfd_bool_bfd_false_error (abfd);
3469 struct bfd_link_hash_table *
3470 _bfd_nolink_bfd_link_hash_table_create (bfd *abfd)
3472 return (struct bfd_link_hash_table *) _bfd_ptr_bfd_null_error (abfd);
3475 void
3476 _bfd_nolink_bfd_link_just_syms (asection *sec ATTRIBUTE_UNUSED,
3477 struct bfd_link_info *info ATTRIBUTE_UNUSED)
3481 void
3482 _bfd_nolink_bfd_copy_link_hash_symbol_type
3483 (bfd *abfd ATTRIBUTE_UNUSED,
3484 struct bfd_link_hash_entry *from ATTRIBUTE_UNUSED,
3485 struct bfd_link_hash_entry *to ATTRIBUTE_UNUSED)
3489 bfd_boolean
3490 _bfd_nolink_bfd_link_split_section (bfd *abfd, asection *sec ATTRIBUTE_UNUSED)
3492 return _bfd_bool_bfd_false_error (abfd);
3495 bfd_boolean
3496 _bfd_nolink_section_already_linked (bfd *abfd,
3497 asection *sec ATTRIBUTE_UNUSED,
3498 struct bfd_link_info *info ATTRIBUTE_UNUSED)
3500 return _bfd_bool_bfd_false_error (abfd);
3503 bfd_boolean
3504 _bfd_nolink_bfd_define_common_symbol
3505 (bfd *abfd,
3506 struct bfd_link_info *info ATTRIBUTE_UNUSED,
3507 struct bfd_link_hash_entry *h ATTRIBUTE_UNUSED)
3509 return _bfd_bool_bfd_false_error (abfd);
3512 struct bfd_link_hash_entry *
3513 _bfd_nolink_bfd_define_start_stop (struct bfd_link_info *info ATTRIBUTE_UNUSED,
3514 const char *name ATTRIBUTE_UNUSED,
3515 asection *sec)
3517 return (struct bfd_link_hash_entry *) _bfd_ptr_bfd_null_error (sec->owner);