* doc/binutils.texi (objdump): Document support for disassembling the 440 PowerPC...
[binutils.git] / bfd / linker.c
blobb9aaf008b378115e20415c60f89e9517dc64fe71
1 /* linker.c -- BFD linker routines
2 Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
3 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
4 Written by Steve Chamberlain and Ian Lance Taylor, Cygnus Support
6 This file is part of BFD, the Binary File Descriptor library.
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */
22 #include "bfd.h"
23 #include "sysdep.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 <<creator>>
153 field of the hash table must be checked to make sure that the
154 hash table was 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 <<creator>> field 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.
226 @findex _bfd_generic_link_add_archive_symbols
227 In most cases the work of looking through the symbols in the
228 archive should be done by the
229 <<_bfd_generic_link_add_archive_symbols>> function. This
230 function builds a hash table from the archive symbol table and
231 looks through the list of undefined symbols to see which
232 elements should be included.
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.
238 The function passed to
239 <<_bfd_generic_link_add_archive_symbols>> must read the
240 symbols of the archive element and decide whether the archive
241 element should be included in the link. If the element is to
242 be included, the <<add_archive_element>> linker callback
243 routine must be called with the element as an argument, and
244 the elements symbols must be added to the linker hash table
245 just as though the element had itself been passed to the
246 <<_bfd_link_add_symbols>> function.
248 When the a.out <<_bfd_link_add_symbols>> function receives an
249 archive, it calls <<_bfd_generic_link_add_archive_symbols>>
250 passing <<aout_link_check_archive_element>> as the function
251 argument. <<aout_link_check_archive_element>> calls
252 <<aout_link_check_ar_symbols>>. If the latter decides to add
253 the element (an element is only added if it provides a real,
254 non-common, definition for a previously undefined or common
255 symbol) it calls the <<add_archive_element>> callback and then
256 <<aout_link_check_archive_element>> calls
257 <<aout_link_add_symbols>> to actually add the symbols to the
258 linker hash table.
260 The ECOFF back end is unusual in that it does not normally
261 call <<_bfd_generic_link_add_archive_symbols>>, because ECOFF
262 archives already contain a hash table of symbols. The ECOFF
263 back end searches the archive itself to avoid the overhead of
264 creating a new hash table.
266 INODE
267 Performing the Final Link, , Adding Symbols to the Hash Table, Linker Functions
268 SUBSECTION
269 Performing the final link
271 @cindex _bfd_link_final_link in target vector
272 @cindex target vector (_bfd_final_link)
273 When all the input files have been processed, the linker calls
274 the <<_bfd_final_link>> entry point of the output BFD. This
275 routine is responsible for producing the final output file,
276 which has several aspects. It must relocate the contents of
277 the input sections and copy the data into the output sections.
278 It must build an output symbol table including any local
279 symbols from the input files and the global symbols from the
280 hash table. When producing relocatable output, it must
281 modify the input relocs and write them into the output file.
282 There may also be object format dependent work to be done.
284 The linker will also call the <<write_object_contents>> entry
285 point when the BFD is closed. The two entry points must work
286 together in order to produce the correct output file.
288 The details of how this works are inevitably dependent upon
289 the specific object file format. The a.out
290 <<_bfd_final_link>> routine is <<NAME(aout,final_link)>>.
292 @menu
293 @* Information provided by the linker::
294 @* Relocating the section contents::
295 @* Writing the symbol table::
296 @end menu
298 INODE
299 Information provided by the linker, Relocating the section contents, Performing the Final Link, Performing the Final Link
300 SUBSUBSECTION
301 Information provided by the linker
303 Before the linker calls the <<_bfd_final_link>> entry point,
304 it sets up some data structures for the function to use.
306 The <<input_bfds>> field of the <<bfd_link_info>> structure
307 will point to a list of all the input files included in the
308 link. These files are linked through the <<link_next>> field
309 of the <<bfd>> structure.
311 Each section in the output file will have a list of
312 <<link_order>> structures attached to the <<map_head.link_order>>
313 field (the <<link_order>> structure is defined in
314 <<bfdlink.h>>). These structures describe how to create the
315 contents of the output section in terms of the contents of
316 various input sections, fill constants, and, eventually, other
317 types of information. They also describe relocs that must be
318 created by the BFD backend, but do not correspond to any input
319 file; this is used to support -Ur, which builds constructors
320 while generating a relocatable object file.
322 INODE
323 Relocating the section contents, Writing the symbol table, Information provided by the linker, Performing the Final Link
324 SUBSUBSECTION
325 Relocating the section contents
327 The <<_bfd_final_link>> function should look through the
328 <<link_order>> structures attached to each section of the
329 output file. Each <<link_order>> structure should either be
330 handled specially, or it should be passed to the function
331 <<_bfd_default_link_order>> which will do the right thing
332 (<<_bfd_default_link_order>> is defined in <<linker.c>>).
334 For efficiency, a <<link_order>> of type
335 <<bfd_indirect_link_order>> whose associated section belongs
336 to a BFD of the same format as the output BFD must be handled
337 specially. This type of <<link_order>> describes part of an
338 output section in terms of a section belonging to one of the
339 input files. The <<_bfd_final_link>> function should read the
340 contents of the section and any associated relocs, apply the
341 relocs to the section contents, and write out the modified
342 section contents. If performing a relocatable link, the
343 relocs themselves must also be modified and written out.
345 @findex _bfd_relocate_contents
346 @findex _bfd_final_link_relocate
347 The functions <<_bfd_relocate_contents>> and
348 <<_bfd_final_link_relocate>> provide some general support for
349 performing the actual relocations, notably overflow checking.
350 Their arguments include information about the symbol the
351 relocation is against and a <<reloc_howto_type>> argument
352 which describes the relocation to perform. These functions
353 are defined in <<reloc.c>>.
355 The a.out function which handles reading, relocating, and
356 writing section contents is <<aout_link_input_section>>. The
357 actual relocation is done in <<aout_link_input_section_std>>
358 and <<aout_link_input_section_ext>>.
360 INODE
361 Writing the symbol table, , Relocating the section contents, Performing the Final Link
362 SUBSUBSECTION
363 Writing the symbol table
365 The <<_bfd_final_link>> function must gather all the symbols
366 in the input files and write them out. It must also write out
367 all the symbols in the global hash table. This must be
368 controlled by the <<strip>> and <<discard>> fields of the
369 <<bfd_link_info>> structure.
371 The local symbols of the input files will not have been
372 entered into the linker hash table. The <<_bfd_final_link>>
373 routine must consider each input file and include the symbols
374 in the output file. It may be convenient to do this when
375 looking through the <<link_order>> structures, or it may be
376 done by stepping through the <<input_bfds>> list.
378 The <<_bfd_final_link>> routine must also traverse the global
379 hash table to gather all the externally visible symbols. It
380 is possible that most of the externally visible symbols may be
381 written out when considering the symbols of each input file,
382 but it is still necessary to traverse the hash table since the
383 linker script may have defined some symbols that are not in
384 any of the input files.
386 The <<strip>> field of the <<bfd_link_info>> structure
387 controls which symbols are written out. The possible values
388 are listed in <<bfdlink.h>>. If the value is <<strip_some>>,
389 then the <<keep_hash>> field of the <<bfd_link_info>>
390 structure is a hash table of symbols to keep; each symbol
391 should be looked up in this hash table, and only symbols which
392 are present should be included in the output file.
394 If the <<strip>> field of the <<bfd_link_info>> structure
395 permits local symbols to be written out, the <<discard>> field
396 is used to further controls which local symbols are included
397 in the output file. If the value is <<discard_l>>, then all
398 local symbols which begin with a certain prefix are discarded;
399 this is controlled by the <<bfd_is_local_label_name>> entry point.
401 The a.out backend handles symbols by calling
402 <<aout_link_write_symbols>> on each input BFD and then
403 traversing the global hash table with the function
404 <<aout_link_write_other_symbol>>. It builds a string table
405 while writing out the symbols, which is written to the output
406 file at the end of <<NAME(aout,final_link)>>.
409 static bfd_boolean generic_link_add_object_symbols
410 (bfd *, struct bfd_link_info *, bfd_boolean collect);
411 static bfd_boolean generic_link_add_symbols
412 (bfd *, struct bfd_link_info *, bfd_boolean);
413 static bfd_boolean generic_link_check_archive_element_no_collect
414 (bfd *, struct bfd_link_info *, bfd_boolean *);
415 static bfd_boolean generic_link_check_archive_element_collect
416 (bfd *, struct bfd_link_info *, bfd_boolean *);
417 static bfd_boolean generic_link_check_archive_element
418 (bfd *, struct bfd_link_info *, bfd_boolean *, bfd_boolean);
419 static bfd_boolean generic_link_add_symbol_list
420 (bfd *, struct bfd_link_info *, bfd_size_type count, asymbol **,
421 bfd_boolean);
422 static bfd_boolean generic_add_output_symbol
423 (bfd *, size_t *psymalloc, asymbol *);
424 static bfd_boolean default_data_link_order
425 (bfd *, struct bfd_link_info *, asection *, struct bfd_link_order *);
426 static bfd_boolean default_indirect_link_order
427 (bfd *, struct bfd_link_info *, asection *, struct bfd_link_order *,
428 bfd_boolean);
430 /* The link hash table structure is defined in bfdlink.h. It provides
431 a base hash table which the backend specific hash tables are built
432 upon. */
434 /* Routine to create an entry in the link hash table. */
436 struct bfd_hash_entry *
437 _bfd_link_hash_newfunc (struct bfd_hash_entry *entry,
438 struct bfd_hash_table *table,
439 const char *string)
441 /* Allocate the structure if it has not already been allocated by a
442 subclass. */
443 if (entry == NULL)
445 entry = bfd_hash_allocate (table, sizeof (struct bfd_link_hash_entry));
446 if (entry == NULL)
447 return entry;
450 /* Call the allocation method of the superclass. */
451 entry = bfd_hash_newfunc (entry, table, string);
452 if (entry)
454 struct bfd_link_hash_entry *h = (struct bfd_link_hash_entry *) entry;
456 /* Initialize the local fields. */
457 h->type = bfd_link_hash_new;
458 memset (&h->u.undef.next, 0,
459 (sizeof (struct bfd_link_hash_entry)
460 - offsetof (struct bfd_link_hash_entry, u.undef.next)));
463 return entry;
466 /* Initialize a link hash table. The BFD argument is the one
467 responsible for creating this table. */
469 bfd_boolean
470 _bfd_link_hash_table_init
471 (struct bfd_link_hash_table *table,
472 bfd *abfd,
473 struct bfd_hash_entry *(*newfunc) (struct bfd_hash_entry *,
474 struct bfd_hash_table *,
475 const char *),
476 unsigned int entsize)
478 table->creator = abfd->xvec;
479 table->undefs = NULL;
480 table->undefs_tail = NULL;
481 table->type = bfd_link_generic_hash_table;
483 return bfd_hash_table_init (&table->table, newfunc, entsize);
486 /* Look up a symbol in a link hash table. If follow is TRUE, we
487 follow bfd_link_hash_indirect and bfd_link_hash_warning links to
488 the real symbol. */
490 struct bfd_link_hash_entry *
491 bfd_link_hash_lookup (struct bfd_link_hash_table *table,
492 const char *string,
493 bfd_boolean create,
494 bfd_boolean copy,
495 bfd_boolean follow)
497 struct bfd_link_hash_entry *ret;
499 ret = ((struct bfd_link_hash_entry *)
500 bfd_hash_lookup (&table->table, string, create, copy));
502 if (follow && ret != NULL)
504 while (ret->type == bfd_link_hash_indirect
505 || ret->type == bfd_link_hash_warning)
506 ret = ret->u.i.link;
509 return ret;
512 /* Look up a symbol in the main linker hash table if the symbol might
513 be wrapped. This should only be used for references to an
514 undefined symbol, not for definitions of a symbol. */
516 struct bfd_link_hash_entry *
517 bfd_wrapped_link_hash_lookup (bfd *abfd,
518 struct bfd_link_info *info,
519 const char *string,
520 bfd_boolean create,
521 bfd_boolean copy,
522 bfd_boolean follow)
524 bfd_size_type amt;
526 if (info->wrap_hash != NULL)
528 const char *l;
529 char prefix = '\0';
531 l = string;
532 if (*l == bfd_get_symbol_leading_char (abfd) || *l == info->wrap_char)
534 prefix = *l;
535 ++l;
538 #undef WRAP
539 #define WRAP "__wrap_"
541 if (bfd_hash_lookup (info->wrap_hash, l, FALSE, FALSE) != NULL)
543 char *n;
544 struct bfd_link_hash_entry *h;
546 /* This symbol is being wrapped. We want to replace all
547 references to SYM with references to __wrap_SYM. */
549 amt = strlen (l) + sizeof WRAP + 1;
550 n = bfd_malloc (amt);
551 if (n == NULL)
552 return NULL;
554 n[0] = prefix;
555 n[1] = '\0';
556 strcat (n, WRAP);
557 strcat (n, l);
558 h = bfd_link_hash_lookup (info->hash, n, create, TRUE, follow);
559 free (n);
560 return h;
563 #undef WRAP
565 #undef REAL
566 #define REAL "__real_"
568 if (*l == '_'
569 && CONST_STRNEQ (l, REAL)
570 && bfd_hash_lookup (info->wrap_hash, l + sizeof REAL - 1,
571 FALSE, FALSE) != NULL)
573 char *n;
574 struct bfd_link_hash_entry *h;
576 /* This is a reference to __real_SYM, where SYM is being
577 wrapped. We want to replace all references to __real_SYM
578 with references to SYM. */
580 amt = strlen (l + sizeof REAL - 1) + 2;
581 n = bfd_malloc (amt);
582 if (n == NULL)
583 return NULL;
585 n[0] = prefix;
586 n[1] = '\0';
587 strcat (n, l + sizeof REAL - 1);
588 h = bfd_link_hash_lookup (info->hash, n, create, TRUE, follow);
589 free (n);
590 return h;
593 #undef REAL
596 return bfd_link_hash_lookup (info->hash, string, create, copy, follow);
599 /* Traverse a generic link hash table. The only reason this is not a
600 macro is to do better type checking. This code presumes that an
601 argument passed as a struct bfd_hash_entry * may be caught as a
602 struct bfd_link_hash_entry * with no explicit cast required on the
603 call. */
605 void
606 bfd_link_hash_traverse
607 (struct bfd_link_hash_table *table,
608 bfd_boolean (*func) (struct bfd_link_hash_entry *, void *),
609 void *info)
611 bfd_hash_traverse (&table->table,
612 (bfd_boolean (*) (struct bfd_hash_entry *, void *)) func,
613 info);
616 /* Add a symbol to the linker hash table undefs list. */
618 void
619 bfd_link_add_undef (struct bfd_link_hash_table *table,
620 struct bfd_link_hash_entry *h)
622 BFD_ASSERT (h->u.undef.next == NULL);
623 if (table->undefs_tail != NULL)
624 table->undefs_tail->u.undef.next = h;
625 if (table->undefs == NULL)
626 table->undefs = h;
627 table->undefs_tail = h;
630 /* The undefs list was designed so that in normal use we don't need to
631 remove entries. However, if symbols on the list are changed from
632 bfd_link_hash_undefined to either bfd_link_hash_undefweak or
633 bfd_link_hash_new for some reason, then they must be removed from the
634 list. Failure to do so might result in the linker attempting to add
635 the symbol to the list again at a later stage. */
637 void
638 bfd_link_repair_undef_list (struct bfd_link_hash_table *table)
640 struct bfd_link_hash_entry **pun;
642 pun = &table->undefs;
643 while (*pun != NULL)
645 struct bfd_link_hash_entry *h = *pun;
647 if (h->type == bfd_link_hash_new
648 || h->type == bfd_link_hash_undefweak)
650 *pun = h->u.undef.next;
651 h->u.undef.next = NULL;
652 if (h == table->undefs_tail)
654 if (pun == &table->undefs)
655 table->undefs_tail = NULL;
656 else
657 /* pun points at an u.undef.next field. Go back to
658 the start of the link_hash_entry. */
659 table->undefs_tail = (struct bfd_link_hash_entry *)
660 ((char *) pun - ((char *) &h->u.undef.next - (char *) h));
661 break;
664 else
665 pun = &h->u.undef.next;
669 /* Routine to create an entry in a generic link hash table. */
671 struct bfd_hash_entry *
672 _bfd_generic_link_hash_newfunc (struct bfd_hash_entry *entry,
673 struct bfd_hash_table *table,
674 const char *string)
676 /* Allocate the structure if it has not already been allocated by a
677 subclass. */
678 if (entry == NULL)
680 entry =
681 bfd_hash_allocate (table, sizeof (struct generic_link_hash_entry));
682 if (entry == NULL)
683 return entry;
686 /* Call the allocation method of the superclass. */
687 entry = _bfd_link_hash_newfunc (entry, table, string);
688 if (entry)
690 struct generic_link_hash_entry *ret;
692 /* Set local fields. */
693 ret = (struct generic_link_hash_entry *) entry;
694 ret->written = FALSE;
695 ret->sym = NULL;
698 return entry;
701 /* Create a generic link hash table. */
703 struct bfd_link_hash_table *
704 _bfd_generic_link_hash_table_create (bfd *abfd)
706 struct generic_link_hash_table *ret;
707 bfd_size_type amt = sizeof (struct generic_link_hash_table);
709 ret = bfd_malloc (amt);
710 if (ret == NULL)
711 return NULL;
712 if (! _bfd_link_hash_table_init (&ret->root, abfd,
713 _bfd_generic_link_hash_newfunc,
714 sizeof (struct generic_link_hash_entry)))
716 free (ret);
717 return NULL;
719 return &ret->root;
722 void
723 _bfd_generic_link_hash_table_free (struct bfd_link_hash_table *hash)
725 struct generic_link_hash_table *ret
726 = (struct generic_link_hash_table *) hash;
728 bfd_hash_table_free (&ret->root.table);
729 free (ret);
732 /* Grab the symbols for an object file when doing a generic link. We
733 store the symbols in the outsymbols field. We need to keep them
734 around for the entire link to ensure that we only read them once.
735 If we read them multiple times, we might wind up with relocs and
736 the hash table pointing to different instances of the symbol
737 structure. */
739 static bfd_boolean
740 generic_link_read_symbols (bfd *abfd)
742 if (bfd_get_outsymbols (abfd) == NULL)
744 long symsize;
745 long symcount;
747 symsize = bfd_get_symtab_upper_bound (abfd);
748 if (symsize < 0)
749 return FALSE;
750 bfd_get_outsymbols (abfd) = bfd_alloc (abfd, symsize);
751 if (bfd_get_outsymbols (abfd) == NULL && symsize != 0)
752 return FALSE;
753 symcount = bfd_canonicalize_symtab (abfd, bfd_get_outsymbols (abfd));
754 if (symcount < 0)
755 return FALSE;
756 bfd_get_symcount (abfd) = symcount;
759 return TRUE;
762 /* Generic function to add symbols to from an object file to the
763 global hash table. This version does not automatically collect
764 constructors by name. */
766 bfd_boolean
767 _bfd_generic_link_add_symbols (bfd *abfd, struct bfd_link_info *info)
769 return generic_link_add_symbols (abfd, info, FALSE);
772 /* Generic function to add symbols from an object file to the global
773 hash table. This version automatically collects constructors by
774 name, as the collect2 program does. It should be used for any
775 target which does not provide some other mechanism for setting up
776 constructors and destructors; these are approximately those targets
777 for which gcc uses collect2 and do not support stabs. */
779 bfd_boolean
780 _bfd_generic_link_add_symbols_collect (bfd *abfd, struct bfd_link_info *info)
782 return generic_link_add_symbols (abfd, info, TRUE);
785 /* Indicate that we are only retrieving symbol values from this
786 section. We want the symbols to act as though the values in the
787 file are absolute. */
789 void
790 _bfd_generic_link_just_syms (asection *sec,
791 struct bfd_link_info *info ATTRIBUTE_UNUSED)
793 sec->output_section = bfd_abs_section_ptr;
794 sec->output_offset = sec->vma;
797 /* Add symbols from an object file to the global hash table. */
799 static bfd_boolean
800 generic_link_add_symbols (bfd *abfd,
801 struct bfd_link_info *info,
802 bfd_boolean collect)
804 bfd_boolean ret;
806 switch (bfd_get_format (abfd))
808 case bfd_object:
809 ret = generic_link_add_object_symbols (abfd, info, collect);
810 break;
811 case bfd_archive:
812 ret = (_bfd_generic_link_add_archive_symbols
813 (abfd, info,
814 (collect
815 ? generic_link_check_archive_element_collect
816 : generic_link_check_archive_element_no_collect)));
817 break;
818 default:
819 bfd_set_error (bfd_error_wrong_format);
820 ret = FALSE;
823 return ret;
826 /* Add symbols from an object file to the global hash table. */
828 static bfd_boolean
829 generic_link_add_object_symbols (bfd *abfd,
830 struct bfd_link_info *info,
831 bfd_boolean collect)
833 bfd_size_type symcount;
834 struct bfd_symbol **outsyms;
836 if (! generic_link_read_symbols (abfd))
837 return FALSE;
838 symcount = _bfd_generic_link_get_symcount (abfd);
839 outsyms = _bfd_generic_link_get_symbols (abfd);
840 return generic_link_add_symbol_list (abfd, info, symcount, outsyms, collect);
843 /* We build a hash table of all symbols defined in an archive. */
845 /* An archive symbol may be defined by multiple archive elements.
846 This linked list is used to hold the elements. */
848 struct archive_list
850 struct archive_list *next;
851 unsigned int indx;
854 /* An entry in an archive hash table. */
856 struct archive_hash_entry
858 struct bfd_hash_entry root;
859 /* Where the symbol is defined. */
860 struct archive_list *defs;
863 /* An archive hash table itself. */
865 struct archive_hash_table
867 struct bfd_hash_table table;
870 /* Create a new entry for an archive hash table. */
872 static struct bfd_hash_entry *
873 archive_hash_newfunc (struct bfd_hash_entry *entry,
874 struct bfd_hash_table *table,
875 const char *string)
877 struct archive_hash_entry *ret = (struct archive_hash_entry *) entry;
879 /* Allocate the structure if it has not already been allocated by a
880 subclass. */
881 if (ret == NULL)
882 ret = bfd_hash_allocate (table, sizeof (struct archive_hash_entry));
883 if (ret == NULL)
884 return NULL;
886 /* Call the allocation method of the superclass. */
887 ret = ((struct archive_hash_entry *)
888 bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));
890 if (ret)
892 /* Initialize the local fields. */
893 ret->defs = NULL;
896 return &ret->root;
899 /* Initialize an archive hash table. */
901 static bfd_boolean
902 archive_hash_table_init
903 (struct archive_hash_table *table,
904 struct bfd_hash_entry *(*newfunc) (struct bfd_hash_entry *,
905 struct bfd_hash_table *,
906 const char *),
907 unsigned int entsize)
909 return bfd_hash_table_init (&table->table, newfunc, entsize);
912 /* Look up an entry in an archive hash table. */
914 #define archive_hash_lookup(t, string, create, copy) \
915 ((struct archive_hash_entry *) \
916 bfd_hash_lookup (&(t)->table, (string), (create), (copy)))
918 /* Allocate space in an archive hash table. */
920 #define archive_hash_allocate(t, size) bfd_hash_allocate (&(t)->table, (size))
922 /* Free an archive hash table. */
924 #define archive_hash_table_free(t) bfd_hash_table_free (&(t)->table)
926 /* Generic function to add symbols from an archive file to the global
927 hash file. This function presumes that the archive symbol table
928 has already been read in (this is normally done by the
929 bfd_check_format entry point). It looks through the undefined and
930 common symbols and searches the archive symbol table for them. If
931 it finds an entry, it includes the associated object file in the
932 link.
934 The old linker looked through the archive symbol table for
935 undefined symbols. We do it the other way around, looking through
936 undefined symbols for symbols defined in the archive. The
937 advantage of the newer scheme is that we only have to look through
938 the list of undefined symbols once, whereas the old method had to
939 re-search the symbol table each time a new object file was added.
941 The CHECKFN argument is used to see if an object file should be
942 included. CHECKFN should set *PNEEDED to TRUE if the object file
943 should be included, and must also call the bfd_link_info
944 add_archive_element callback function and handle adding the symbols
945 to the global hash table. CHECKFN should only return FALSE if some
946 sort of error occurs.
948 For some formats, such as a.out, it is possible to look through an
949 object file but not actually include it in the link. The
950 archive_pass field in a BFD is used to avoid checking the symbols
951 of an object files too many times. When an object is included in
952 the link, archive_pass is set to -1. If an object is scanned but
953 not included, archive_pass is set to the pass number. The pass
954 number is incremented each time a new object file is included. The
955 pass number is used because when a new object file is included it
956 may create new undefined symbols which cause a previously examined
957 object file to be included. */
959 bfd_boolean
960 _bfd_generic_link_add_archive_symbols
961 (bfd *abfd,
962 struct bfd_link_info *info,
963 bfd_boolean (*checkfn) (bfd *, struct bfd_link_info *, bfd_boolean *))
965 carsym *arsyms;
966 carsym *arsym_end;
967 register carsym *arsym;
968 int pass;
969 struct archive_hash_table arsym_hash;
970 unsigned int indx;
971 struct bfd_link_hash_entry **pundef;
973 if (! bfd_has_map (abfd))
975 /* An empty archive is a special case. */
976 if (bfd_openr_next_archived_file (abfd, NULL) == NULL)
977 return TRUE;
978 bfd_set_error (bfd_error_no_armap);
979 return FALSE;
982 arsyms = bfd_ardata (abfd)->symdefs;
983 arsym_end = arsyms + bfd_ardata (abfd)->symdef_count;
985 /* In order to quickly determine whether an symbol is defined in
986 this archive, we build a hash table of the symbols. */
987 if (! archive_hash_table_init (&arsym_hash, archive_hash_newfunc,
988 sizeof (struct archive_hash_entry)))
989 return FALSE;
990 for (arsym = arsyms, indx = 0; arsym < arsym_end; arsym++, indx++)
992 struct archive_hash_entry *arh;
993 struct archive_list *l, **pp;
995 arh = archive_hash_lookup (&arsym_hash, arsym->name, TRUE, FALSE);
996 if (arh == NULL)
997 goto error_return;
998 l = ((struct archive_list *)
999 archive_hash_allocate (&arsym_hash, sizeof (struct archive_list)));
1000 if (l == NULL)
1001 goto error_return;
1002 l->indx = indx;
1003 for (pp = &arh->defs; *pp != NULL; pp = &(*pp)->next)
1005 *pp = l;
1006 l->next = NULL;
1009 /* The archive_pass field in the archive itself is used to
1010 initialize PASS, sine we may search the same archive multiple
1011 times. */
1012 pass = abfd->archive_pass + 1;
1014 /* New undefined symbols are added to the end of the list, so we
1015 only need to look through it once. */
1016 pundef = &info->hash->undefs;
1017 while (*pundef != NULL)
1019 struct bfd_link_hash_entry *h;
1020 struct archive_hash_entry *arh;
1021 struct archive_list *l;
1023 h = *pundef;
1025 /* When a symbol is defined, it is not necessarily removed from
1026 the list. */
1027 if (h->type != bfd_link_hash_undefined
1028 && h->type != bfd_link_hash_common)
1030 /* Remove this entry from the list, for general cleanliness
1031 and because we are going to look through the list again
1032 if we search any more libraries. We can't remove the
1033 entry if it is the tail, because that would lose any
1034 entries we add to the list later on (it would also cause
1035 us to lose track of whether the symbol has been
1036 referenced). */
1037 if (*pundef != info->hash->undefs_tail)
1038 *pundef = (*pundef)->u.undef.next;
1039 else
1040 pundef = &(*pundef)->u.undef.next;
1041 continue;
1044 /* Look for this symbol in the archive symbol map. */
1045 arh = archive_hash_lookup (&arsym_hash, h->root.string, FALSE, FALSE);
1046 if (arh == NULL)
1048 /* If we haven't found the exact symbol we're looking for,
1049 let's look for its import thunk */
1050 if (info->pei386_auto_import)
1052 bfd_size_type amt = strlen (h->root.string) + 10;
1053 char *buf = bfd_malloc (amt);
1054 if (buf == NULL)
1055 return FALSE;
1057 sprintf (buf, "__imp_%s", h->root.string);
1058 arh = archive_hash_lookup (&arsym_hash, buf, FALSE, FALSE);
1059 free(buf);
1061 if (arh == NULL)
1063 pundef = &(*pundef)->u.undef.next;
1064 continue;
1067 /* Look at all the objects which define this symbol. */
1068 for (l = arh->defs; l != NULL; l = l->next)
1070 bfd *element;
1071 bfd_boolean needed;
1073 /* If the symbol has gotten defined along the way, quit. */
1074 if (h->type != bfd_link_hash_undefined
1075 && h->type != bfd_link_hash_common)
1076 break;
1078 element = bfd_get_elt_at_index (abfd, l->indx);
1079 if (element == NULL)
1080 goto error_return;
1082 /* If we've already included this element, or if we've
1083 already checked it on this pass, continue. */
1084 if (element->archive_pass == -1
1085 || element->archive_pass == pass)
1086 continue;
1088 /* If we can't figure this element out, just ignore it. */
1089 if (! bfd_check_format (element, bfd_object))
1091 element->archive_pass = -1;
1092 continue;
1095 /* CHECKFN will see if this element should be included, and
1096 go ahead and include it if appropriate. */
1097 if (! (*checkfn) (element, info, &needed))
1098 goto error_return;
1100 if (! needed)
1101 element->archive_pass = pass;
1102 else
1104 element->archive_pass = -1;
1106 /* Increment the pass count to show that we may need to
1107 recheck object files which were already checked. */
1108 ++pass;
1112 pundef = &(*pundef)->u.undef.next;
1115 archive_hash_table_free (&arsym_hash);
1117 /* Save PASS in case we are called again. */
1118 abfd->archive_pass = pass;
1120 return TRUE;
1122 error_return:
1123 archive_hash_table_free (&arsym_hash);
1124 return FALSE;
1127 /* See if we should include an archive element. This version is used
1128 when we do not want to automatically collect constructors based on
1129 the symbol name, presumably because we have some other mechanism
1130 for finding them. */
1132 static bfd_boolean
1133 generic_link_check_archive_element_no_collect (
1134 bfd *abfd,
1135 struct bfd_link_info *info,
1136 bfd_boolean *pneeded)
1138 return generic_link_check_archive_element (abfd, info, pneeded, FALSE);
1141 /* See if we should include an archive element. This version is used
1142 when we want to automatically collect constructors based on the
1143 symbol name, as collect2 does. */
1145 static bfd_boolean
1146 generic_link_check_archive_element_collect (bfd *abfd,
1147 struct bfd_link_info *info,
1148 bfd_boolean *pneeded)
1150 return generic_link_check_archive_element (abfd, info, pneeded, TRUE);
1153 /* See if we should include an archive element. Optionally collect
1154 constructors. */
1156 static bfd_boolean
1157 generic_link_check_archive_element (bfd *abfd,
1158 struct bfd_link_info *info,
1159 bfd_boolean *pneeded,
1160 bfd_boolean collect)
1162 asymbol **pp, **ppend;
1164 *pneeded = FALSE;
1166 if (! generic_link_read_symbols (abfd))
1167 return FALSE;
1169 pp = _bfd_generic_link_get_symbols (abfd);
1170 ppend = pp + _bfd_generic_link_get_symcount (abfd);
1171 for (; pp < ppend; pp++)
1173 asymbol *p;
1174 struct bfd_link_hash_entry *h;
1176 p = *pp;
1178 /* We are only interested in globally visible symbols. */
1179 if (! bfd_is_com_section (p->section)
1180 && (p->flags & (BSF_GLOBAL | BSF_INDIRECT | BSF_WEAK)) == 0)
1181 continue;
1183 /* We are only interested if we know something about this
1184 symbol, and it is undefined or common. An undefined weak
1185 symbol (type bfd_link_hash_undefweak) is not considered to be
1186 a reference when pulling files out of an archive. See the
1187 SVR4 ABI, p. 4-27. */
1188 h = bfd_link_hash_lookup (info->hash, bfd_asymbol_name (p), FALSE,
1189 FALSE, TRUE);
1190 if (h == NULL
1191 || (h->type != bfd_link_hash_undefined
1192 && h->type != bfd_link_hash_common))
1193 continue;
1195 /* P is a symbol we are looking for. */
1197 if (! bfd_is_com_section (p->section))
1199 bfd_size_type symcount;
1200 asymbol **symbols;
1202 /* This object file defines this symbol, so pull it in. */
1203 if (! (*info->callbacks->add_archive_element) (info, abfd,
1204 bfd_asymbol_name (p)))
1205 return FALSE;
1206 symcount = _bfd_generic_link_get_symcount (abfd);
1207 symbols = _bfd_generic_link_get_symbols (abfd);
1208 if (! generic_link_add_symbol_list (abfd, info, symcount,
1209 symbols, collect))
1210 return FALSE;
1211 *pneeded = TRUE;
1212 return TRUE;
1215 /* P is a common symbol. */
1217 if (h->type == bfd_link_hash_undefined)
1219 bfd *symbfd;
1220 bfd_vma size;
1221 unsigned int power;
1223 symbfd = h->u.undef.abfd;
1224 if (symbfd == NULL)
1226 /* This symbol was created as undefined from outside
1227 BFD. We assume that we should link in the object
1228 file. This is for the -u option in the linker. */
1229 if (! (*info->callbacks->add_archive_element)
1230 (info, abfd, bfd_asymbol_name (p)))
1231 return FALSE;
1232 *pneeded = TRUE;
1233 return TRUE;
1236 /* Turn the symbol into a common symbol but do not link in
1237 the object file. This is how a.out works. Object
1238 formats that require different semantics must implement
1239 this function differently. This symbol is already on the
1240 undefs list. We add the section to a common section
1241 attached to symbfd to ensure that it is in a BFD which
1242 will be linked in. */
1243 h->type = bfd_link_hash_common;
1244 h->u.c.p =
1245 bfd_hash_allocate (&info->hash->table,
1246 sizeof (struct bfd_link_hash_common_entry));
1247 if (h->u.c.p == NULL)
1248 return FALSE;
1250 size = bfd_asymbol_value (p);
1251 h->u.c.size = size;
1253 power = bfd_log2 (size);
1254 if (power > 4)
1255 power = 4;
1256 h->u.c.p->alignment_power = power;
1258 if (p->section == bfd_com_section_ptr)
1259 h->u.c.p->section = bfd_make_section_old_way (symbfd, "COMMON");
1260 else
1261 h->u.c.p->section = bfd_make_section_old_way (symbfd,
1262 p->section->name);
1263 h->u.c.p->section->flags = SEC_ALLOC;
1265 else
1267 /* Adjust the size of the common symbol if necessary. This
1268 is how a.out works. Object formats that require
1269 different semantics must implement this function
1270 differently. */
1271 if (bfd_asymbol_value (p) > h->u.c.size)
1272 h->u.c.size = bfd_asymbol_value (p);
1276 /* This archive element is not needed. */
1277 return TRUE;
1280 /* Add the symbols from an object file to the global hash table. ABFD
1281 is the object file. INFO is the linker information. SYMBOL_COUNT
1282 is the number of symbols. SYMBOLS is the list of symbols. COLLECT
1283 is TRUE if constructors should be automatically collected by name
1284 as is done by collect2. */
1286 static bfd_boolean
1287 generic_link_add_symbol_list (bfd *abfd,
1288 struct bfd_link_info *info,
1289 bfd_size_type symbol_count,
1290 asymbol **symbols,
1291 bfd_boolean collect)
1293 asymbol **pp, **ppend;
1295 pp = symbols;
1296 ppend = symbols + symbol_count;
1297 for (; pp < ppend; pp++)
1299 asymbol *p;
1301 p = *pp;
1303 if ((p->flags & (BSF_INDIRECT
1304 | BSF_WARNING
1305 | BSF_GLOBAL
1306 | BSF_CONSTRUCTOR
1307 | BSF_WEAK)) != 0
1308 || bfd_is_und_section (bfd_get_section (p))
1309 || bfd_is_com_section (bfd_get_section (p))
1310 || bfd_is_ind_section (bfd_get_section (p)))
1312 const char *name;
1313 const char *string;
1314 struct generic_link_hash_entry *h;
1315 struct bfd_link_hash_entry *bh;
1317 name = bfd_asymbol_name (p);
1318 if (((p->flags & BSF_INDIRECT) != 0
1319 || bfd_is_ind_section (p->section))
1320 && pp + 1 < ppend)
1322 pp++;
1323 string = bfd_asymbol_name (*pp);
1325 else if ((p->flags & BSF_WARNING) != 0
1326 && pp + 1 < ppend)
1328 /* The name of P is actually the warning string, and the
1329 next symbol is the one to warn about. */
1330 string = name;
1331 pp++;
1332 name = bfd_asymbol_name (*pp);
1334 else
1335 string = NULL;
1337 bh = NULL;
1338 if (! (_bfd_generic_link_add_one_symbol
1339 (info, abfd, name, p->flags, bfd_get_section (p),
1340 p->value, string, FALSE, collect, &bh)))
1341 return FALSE;
1342 h = (struct generic_link_hash_entry *) bh;
1344 /* If this is a constructor symbol, and the linker didn't do
1345 anything with it, then we want to just pass the symbol
1346 through to the output file. This will happen when
1347 linking with -r. */
1348 if ((p->flags & BSF_CONSTRUCTOR) != 0
1349 && (h == NULL || h->root.type == bfd_link_hash_new))
1351 p->udata.p = NULL;
1352 continue;
1355 /* Save the BFD symbol so that we don't lose any backend
1356 specific information that may be attached to it. We only
1357 want this one if it gives more information than the
1358 existing one; we don't want to replace a defined symbol
1359 with an undefined one. This routine may be called with a
1360 hash table other than the generic hash table, so we only
1361 do this if we are certain that the hash table is a
1362 generic one. */
1363 if (info->hash->creator == abfd->xvec)
1365 if (h->sym == NULL
1366 || (! bfd_is_und_section (bfd_get_section (p))
1367 && (! bfd_is_com_section (bfd_get_section (p))
1368 || bfd_is_und_section (bfd_get_section (h->sym)))))
1370 h->sym = p;
1371 /* BSF_OLD_COMMON is a hack to support COFF reloc
1372 reading, and it should go away when the COFF
1373 linker is switched to the new version. */
1374 if (bfd_is_com_section (bfd_get_section (p)))
1375 p->flags |= BSF_OLD_COMMON;
1379 /* Store a back pointer from the symbol to the hash
1380 table entry for the benefit of relaxation code until
1381 it gets rewritten to not use asymbol structures.
1382 Setting this is also used to check whether these
1383 symbols were set up by the generic linker. */
1384 p->udata.p = h;
1388 return TRUE;
1391 /* We use a state table to deal with adding symbols from an object
1392 file. The first index into the state table describes the symbol
1393 from the object file. The second index into the state table is the
1394 type of the symbol in the hash table. */
1396 /* The symbol from the object file is turned into one of these row
1397 values. */
1399 enum link_row
1401 UNDEF_ROW, /* Undefined. */
1402 UNDEFW_ROW, /* Weak undefined. */
1403 DEF_ROW, /* Defined. */
1404 DEFW_ROW, /* Weak defined. */
1405 COMMON_ROW, /* Common. */
1406 INDR_ROW, /* Indirect. */
1407 WARN_ROW, /* Warning. */
1408 SET_ROW /* Member of set. */
1411 /* apparently needed for Hitachi 3050R(HI-UX/WE2)? */
1412 #undef FAIL
1414 /* The actions to take in the state table. */
1416 enum link_action
1418 FAIL, /* Abort. */
1419 UND, /* Mark symbol undefined. */
1420 WEAK, /* Mark symbol weak undefined. */
1421 DEF, /* Mark symbol defined. */
1422 DEFW, /* Mark symbol weak defined. */
1423 COM, /* Mark symbol common. */
1424 REF, /* Mark defined symbol referenced. */
1425 CREF, /* Possibly warn about common reference to defined symbol. */
1426 CDEF, /* Define existing common symbol. */
1427 NOACT, /* No action. */
1428 BIG, /* Mark symbol common using largest size. */
1429 MDEF, /* Multiple definition error. */
1430 MIND, /* Multiple indirect symbols. */
1431 IND, /* Make indirect symbol. */
1432 CIND, /* Make indirect symbol from existing common symbol. */
1433 SET, /* Add value to set. */
1434 MWARN, /* Make warning symbol. */
1435 WARN, /* Issue warning. */
1436 CWARN, /* Warn if referenced, else MWARN. */
1437 CYCLE, /* Repeat with symbol pointed to. */
1438 REFC, /* Mark indirect symbol referenced and then CYCLE. */
1439 WARNC /* Issue warning and then CYCLE. */
1442 /* The state table itself. The first index is a link_row and the
1443 second index is a bfd_link_hash_type. */
1445 static const enum link_action link_action[8][8] =
1447 /* current\prev new undef undefw def defw com indr warn */
1448 /* UNDEF_ROW */ {UND, NOACT, UND, REF, REF, NOACT, REFC, WARNC },
1449 /* UNDEFW_ROW */ {WEAK, NOACT, NOACT, REF, REF, NOACT, REFC, WARNC },
1450 /* DEF_ROW */ {DEF, DEF, DEF, MDEF, DEF, CDEF, MDEF, CYCLE },
1451 /* DEFW_ROW */ {DEFW, DEFW, DEFW, NOACT, NOACT, NOACT, NOACT, CYCLE },
1452 /* COMMON_ROW */ {COM, COM, COM, CREF, COM, BIG, REFC, WARNC },
1453 /* INDR_ROW */ {IND, IND, IND, MDEF, IND, CIND, MIND, CYCLE },
1454 /* WARN_ROW */ {MWARN, WARN, WARN, CWARN, CWARN, WARN, CWARN, NOACT },
1455 /* SET_ROW */ {SET, SET, SET, SET, SET, SET, CYCLE, CYCLE }
1458 /* Most of the entries in the LINK_ACTION table are straightforward,
1459 but a few are somewhat subtle.
1461 A reference to an indirect symbol (UNDEF_ROW/indr or
1462 UNDEFW_ROW/indr) is counted as a reference both to the indirect
1463 symbol and to the symbol the indirect symbol points to.
1465 A reference to a warning symbol (UNDEF_ROW/warn or UNDEFW_ROW/warn)
1466 causes the warning to be issued.
1468 A common definition of an indirect symbol (COMMON_ROW/indr) is
1469 treated as a multiple definition error. Likewise for an indirect
1470 definition of a common symbol (INDR_ROW/com).
1472 An indirect definition of a warning (INDR_ROW/warn) does not cause
1473 the warning to be issued.
1475 If a warning is created for an indirect symbol (WARN_ROW/indr) no
1476 warning is created for the symbol the indirect symbol points to.
1478 Adding an entry to a set does not count as a reference to a set,
1479 and no warning is issued (SET_ROW/warn). */
1481 /* Return the BFD in which a hash entry has been defined, if known. */
1483 static bfd *
1484 hash_entry_bfd (struct bfd_link_hash_entry *h)
1486 while (h->type == bfd_link_hash_warning)
1487 h = h->u.i.link;
1488 switch (h->type)
1490 default:
1491 return NULL;
1492 case bfd_link_hash_undefined:
1493 case bfd_link_hash_undefweak:
1494 return h->u.undef.abfd;
1495 case bfd_link_hash_defined:
1496 case bfd_link_hash_defweak:
1497 return h->u.def.section->owner;
1498 case bfd_link_hash_common:
1499 return h->u.c.p->section->owner;
1501 /*NOTREACHED*/
1504 /* Add a symbol to the global hash table.
1505 ABFD is the BFD the symbol comes from.
1506 NAME is the name of the symbol.
1507 FLAGS is the BSF_* bits associated with the symbol.
1508 SECTION is the section in which the symbol is defined; this may be
1509 bfd_und_section_ptr or bfd_com_section_ptr.
1510 VALUE is the value of the symbol, relative to the section.
1511 STRING is used for either an indirect symbol, in which case it is
1512 the name of the symbol to indirect to, or a warning symbol, in
1513 which case it is the warning string.
1514 COPY is TRUE if NAME or STRING must be copied into locally
1515 allocated memory if they need to be saved.
1516 COLLECT is TRUE if we should automatically collect gcc constructor
1517 or destructor names as collect2 does.
1518 HASHP, if not NULL, is a place to store the created hash table
1519 entry; if *HASHP is not NULL, the caller has already looked up
1520 the hash table entry, and stored it in *HASHP. */
1522 bfd_boolean
1523 _bfd_generic_link_add_one_symbol (struct bfd_link_info *info,
1524 bfd *abfd,
1525 const char *name,
1526 flagword flags,
1527 asection *section,
1528 bfd_vma value,
1529 const char *string,
1530 bfd_boolean copy,
1531 bfd_boolean collect,
1532 struct bfd_link_hash_entry **hashp)
1534 enum link_row row;
1535 struct bfd_link_hash_entry *h;
1536 bfd_boolean cycle;
1538 if (bfd_is_ind_section (section)
1539 || (flags & BSF_INDIRECT) != 0)
1540 row = INDR_ROW;
1541 else if ((flags & BSF_WARNING) != 0)
1542 row = WARN_ROW;
1543 else if ((flags & BSF_CONSTRUCTOR) != 0)
1544 row = SET_ROW;
1545 else if (bfd_is_und_section (section))
1547 if ((flags & BSF_WEAK) != 0)
1548 row = UNDEFW_ROW;
1549 else
1550 row = UNDEF_ROW;
1552 else if ((flags & BSF_WEAK) != 0)
1553 row = DEFW_ROW;
1554 else if (bfd_is_com_section (section))
1555 row = COMMON_ROW;
1556 else
1557 row = DEF_ROW;
1559 if (hashp != NULL && *hashp != NULL)
1560 h = *hashp;
1561 else
1563 if (row == UNDEF_ROW || row == UNDEFW_ROW)
1564 h = bfd_wrapped_link_hash_lookup (abfd, info, name, TRUE, copy, FALSE);
1565 else
1566 h = bfd_link_hash_lookup (info->hash, name, TRUE, copy, FALSE);
1567 if (h == NULL)
1569 if (hashp != NULL)
1570 *hashp = NULL;
1571 return FALSE;
1575 if (info->notice_all
1576 || (info->notice_hash != NULL
1577 && bfd_hash_lookup (info->notice_hash, name, FALSE, FALSE) != NULL))
1579 if (! (*info->callbacks->notice) (info, h->root.string, abfd, section,
1580 value))
1581 return FALSE;
1584 if (hashp != NULL)
1585 *hashp = h;
1589 enum link_action action;
1591 cycle = FALSE;
1592 action = link_action[(int) row][(int) h->type];
1593 switch (action)
1595 case FAIL:
1596 abort ();
1598 case NOACT:
1599 /* Do nothing. */
1600 break;
1602 case UND:
1603 /* Make a new undefined symbol. */
1604 h->type = bfd_link_hash_undefined;
1605 h->u.undef.abfd = abfd;
1606 bfd_link_add_undef (info->hash, h);
1607 break;
1609 case WEAK:
1610 /* Make a new weak undefined symbol. */
1611 h->type = bfd_link_hash_undefweak;
1612 h->u.undef.abfd = abfd;
1613 h->u.undef.weak = abfd;
1614 break;
1616 case CDEF:
1617 /* We have found a definition for a symbol which was
1618 previously common. */
1619 BFD_ASSERT (h->type == bfd_link_hash_common);
1620 if (! ((*info->callbacks->multiple_common)
1621 (info, h->root.string,
1622 h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size,
1623 abfd, bfd_link_hash_defined, 0)))
1624 return FALSE;
1625 /* Fall through. */
1626 case DEF:
1627 case DEFW:
1629 enum bfd_link_hash_type oldtype;
1631 /* Define a symbol. */
1632 oldtype = h->type;
1633 if (action == DEFW)
1634 h->type = bfd_link_hash_defweak;
1635 else
1636 h->type = bfd_link_hash_defined;
1637 h->u.def.section = section;
1638 h->u.def.value = value;
1640 /* If we have been asked to, we act like collect2 and
1641 identify all functions that might be global
1642 constructors and destructors and pass them up in a
1643 callback. We only do this for certain object file
1644 types, since many object file types can handle this
1645 automatically. */
1646 if (collect && name[0] == '_')
1648 const char *s;
1650 /* A constructor or destructor name starts like this:
1651 _+GLOBAL_[_.$][ID][_.$] where the first [_.$] and
1652 the second are the same character (we accept any
1653 character there, in case a new object file format
1654 comes along with even worse naming restrictions). */
1656 #define CONS_PREFIX "GLOBAL_"
1657 #define CONS_PREFIX_LEN (sizeof CONS_PREFIX - 1)
1659 s = name + 1;
1660 while (*s == '_')
1661 ++s;
1662 if (s[0] == 'G' && CONST_STRNEQ (s, CONS_PREFIX))
1664 char c;
1666 c = s[CONS_PREFIX_LEN + 1];
1667 if ((c == 'I' || c == 'D')
1668 && s[CONS_PREFIX_LEN] == s[CONS_PREFIX_LEN + 2])
1670 /* If this is a definition of a symbol which
1671 was previously weakly defined, we are in
1672 trouble. We have already added a
1673 constructor entry for the weak defined
1674 symbol, and now we are trying to add one
1675 for the new symbol. Fortunately, this case
1676 should never arise in practice. */
1677 if (oldtype == bfd_link_hash_defweak)
1678 abort ();
1680 if (! ((*info->callbacks->constructor)
1681 (info, c == 'I',
1682 h->root.string, abfd, section, value)))
1683 return FALSE;
1689 break;
1691 case COM:
1692 /* We have found a common definition for a symbol. */
1693 if (h->type == bfd_link_hash_new)
1694 bfd_link_add_undef (info->hash, h);
1695 h->type = bfd_link_hash_common;
1696 h->u.c.p =
1697 bfd_hash_allocate (&info->hash->table,
1698 sizeof (struct bfd_link_hash_common_entry));
1699 if (h->u.c.p == NULL)
1700 return FALSE;
1702 h->u.c.size = value;
1704 /* Select a default alignment based on the size. This may
1705 be overridden by the caller. */
1707 unsigned int power;
1709 power = bfd_log2 (value);
1710 if (power > 4)
1711 power = 4;
1712 h->u.c.p->alignment_power = power;
1715 /* The section of a common symbol is only used if the common
1716 symbol is actually allocated. It basically provides a
1717 hook for the linker script to decide which output section
1718 the common symbols should be put in. In most cases, the
1719 section of a common symbol will be bfd_com_section_ptr,
1720 the code here will choose a common symbol section named
1721 "COMMON", and the linker script will contain *(COMMON) in
1722 the appropriate place. A few targets use separate common
1723 sections for small symbols, and they require special
1724 handling. */
1725 if (section == bfd_com_section_ptr)
1727 h->u.c.p->section = bfd_make_section_old_way (abfd, "COMMON");
1728 h->u.c.p->section->flags = SEC_ALLOC;
1730 else if (section->owner != abfd)
1732 h->u.c.p->section = bfd_make_section_old_way (abfd,
1733 section->name);
1734 h->u.c.p->section->flags = SEC_ALLOC;
1736 else
1737 h->u.c.p->section = section;
1738 break;
1740 case REF:
1741 /* A reference to a defined symbol. */
1742 if (h->u.undef.next == NULL && info->hash->undefs_tail != h)
1743 h->u.undef.next = h;
1744 break;
1746 case BIG:
1747 /* We have found a common definition for a symbol which
1748 already had a common definition. Use the maximum of the
1749 two sizes, and use the section required by the larger symbol. */
1750 BFD_ASSERT (h->type == bfd_link_hash_common);
1751 if (! ((*info->callbacks->multiple_common)
1752 (info, h->root.string,
1753 h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size,
1754 abfd, bfd_link_hash_common, value)))
1755 return FALSE;
1756 if (value > h->u.c.size)
1758 unsigned int power;
1760 h->u.c.size = value;
1762 /* Select a default alignment based on the size. This may
1763 be overridden by the caller. */
1764 power = bfd_log2 (value);
1765 if (power > 4)
1766 power = 4;
1767 h->u.c.p->alignment_power = power;
1769 /* Some systems have special treatment for small commons,
1770 hence we want to select the section used by the larger
1771 symbol. This makes sure the symbol does not go in a
1772 small common section if it is now too large. */
1773 if (section == bfd_com_section_ptr)
1775 h->u.c.p->section
1776 = bfd_make_section_old_way (abfd, "COMMON");
1777 h->u.c.p->section->flags = SEC_ALLOC;
1779 else if (section->owner != abfd)
1781 h->u.c.p->section
1782 = bfd_make_section_old_way (abfd, section->name);
1783 h->u.c.p->section->flags = SEC_ALLOC;
1785 else
1786 h->u.c.p->section = section;
1788 break;
1790 case CREF:
1792 bfd *obfd;
1794 /* We have found a common definition for a symbol which
1795 was already defined. FIXME: It would nice if we could
1796 report the BFD which defined an indirect symbol, but we
1797 don't have anywhere to store the information. */
1798 if (h->type == bfd_link_hash_defined
1799 || h->type == bfd_link_hash_defweak)
1800 obfd = h->u.def.section->owner;
1801 else
1802 obfd = NULL;
1803 if (! ((*info->callbacks->multiple_common)
1804 (info, h->root.string, obfd, h->type, 0,
1805 abfd, bfd_link_hash_common, value)))
1806 return FALSE;
1808 break;
1810 case MIND:
1811 /* Multiple indirect symbols. This is OK if they both point
1812 to the same symbol. */
1813 if (strcmp (h->u.i.link->root.string, string) == 0)
1814 break;
1815 /* Fall through. */
1816 case MDEF:
1817 /* Handle a multiple definition. */
1818 if (!info->allow_multiple_definition)
1820 asection *msec = NULL;
1821 bfd_vma mval = 0;
1823 switch (h->type)
1825 case bfd_link_hash_defined:
1826 msec = h->u.def.section;
1827 mval = h->u.def.value;
1828 break;
1829 case bfd_link_hash_indirect:
1830 msec = bfd_ind_section_ptr;
1831 mval = 0;
1832 break;
1833 default:
1834 abort ();
1837 /* Ignore a redefinition of an absolute symbol to the
1838 same value; it's harmless. */
1839 if (h->type == bfd_link_hash_defined
1840 && bfd_is_abs_section (msec)
1841 && bfd_is_abs_section (section)
1842 && value == mval)
1843 break;
1845 if (! ((*info->callbacks->multiple_definition)
1846 (info, h->root.string, msec->owner, msec, mval,
1847 abfd, section, value)))
1848 return FALSE;
1850 break;
1852 case CIND:
1853 /* Create an indirect symbol from an existing common symbol. */
1854 BFD_ASSERT (h->type == bfd_link_hash_common);
1855 if (! ((*info->callbacks->multiple_common)
1856 (info, h->root.string,
1857 h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size,
1858 abfd, bfd_link_hash_indirect, 0)))
1859 return FALSE;
1860 /* Fall through. */
1861 case IND:
1862 /* Create an indirect symbol. */
1864 struct bfd_link_hash_entry *inh;
1866 /* STRING is the name of the symbol we want to indirect
1867 to. */
1868 inh = bfd_wrapped_link_hash_lookup (abfd, info, string, TRUE,
1869 copy, FALSE);
1870 if (inh == NULL)
1871 return FALSE;
1872 if (inh->type == bfd_link_hash_indirect
1873 && inh->u.i.link == h)
1875 (*_bfd_error_handler)
1876 (_("%B: indirect symbol `%s' to `%s' is a loop"),
1877 abfd, name, string);
1878 bfd_set_error (bfd_error_invalid_operation);
1879 return FALSE;
1881 if (inh->type == bfd_link_hash_new)
1883 inh->type = bfd_link_hash_undefined;
1884 inh->u.undef.abfd = abfd;
1885 bfd_link_add_undef (info->hash, inh);
1888 /* If the indirect symbol has been referenced, we need to
1889 push the reference down to the symbol we are
1890 referencing. */
1891 if (h->type != bfd_link_hash_new)
1893 row = UNDEF_ROW;
1894 cycle = TRUE;
1897 h->type = bfd_link_hash_indirect;
1898 h->u.i.link = inh;
1900 break;
1902 case SET:
1903 /* Add an entry to a set. */
1904 if (! (*info->callbacks->add_to_set) (info, h, BFD_RELOC_CTOR,
1905 abfd, section, value))
1906 return FALSE;
1907 break;
1909 case WARNC:
1910 /* Issue a warning and cycle. */
1911 if (h->u.i.warning != NULL)
1913 if (! (*info->callbacks->warning) (info, h->u.i.warning,
1914 h->root.string, abfd,
1915 NULL, 0))
1916 return FALSE;
1917 /* Only issue a warning once. */
1918 h->u.i.warning = NULL;
1920 /* Fall through. */
1921 case CYCLE:
1922 /* Try again with the referenced symbol. */
1923 h = h->u.i.link;
1924 cycle = TRUE;
1925 break;
1927 case REFC:
1928 /* A reference to an indirect symbol. */
1929 if (h->u.undef.next == NULL && info->hash->undefs_tail != h)
1930 h->u.undef.next = h;
1931 h = h->u.i.link;
1932 cycle = TRUE;
1933 break;
1935 case WARN:
1936 /* Issue a warning. */
1937 if (! (*info->callbacks->warning) (info, string, h->root.string,
1938 hash_entry_bfd (h), NULL, 0))
1939 return FALSE;
1940 break;
1942 case CWARN:
1943 /* Warn if this symbol has been referenced already,
1944 otherwise add a warning. A symbol has been referenced if
1945 the u.undef.next field is not NULL, or it is the tail of the
1946 undefined symbol list. The REF case above helps to
1947 ensure this. */
1948 if (h->u.undef.next != NULL || info->hash->undefs_tail == h)
1950 if (! (*info->callbacks->warning) (info, string, h->root.string,
1951 hash_entry_bfd (h), NULL, 0))
1952 return FALSE;
1953 break;
1955 /* Fall through. */
1956 case MWARN:
1957 /* Make a warning symbol. */
1959 struct bfd_link_hash_entry *sub;
1961 /* STRING is the warning to give. */
1962 sub = ((struct bfd_link_hash_entry *)
1963 ((*info->hash->table.newfunc)
1964 (NULL, &info->hash->table, h->root.string)));
1965 if (sub == NULL)
1966 return FALSE;
1967 *sub = *h;
1968 sub->type = bfd_link_hash_warning;
1969 sub->u.i.link = h;
1970 if (! copy)
1971 sub->u.i.warning = string;
1972 else
1974 char *w;
1975 size_t len = strlen (string) + 1;
1977 w = bfd_hash_allocate (&info->hash->table, len);
1978 if (w == NULL)
1979 return FALSE;
1980 memcpy (w, string, len);
1981 sub->u.i.warning = w;
1984 bfd_hash_replace (&info->hash->table,
1985 (struct bfd_hash_entry *) h,
1986 (struct bfd_hash_entry *) sub);
1987 if (hashp != NULL)
1988 *hashp = sub;
1990 break;
1993 while (cycle);
1995 return TRUE;
1998 /* Generic final link routine. */
2000 bfd_boolean
2001 _bfd_generic_final_link (bfd *abfd, struct bfd_link_info *info)
2003 bfd *sub;
2004 asection *o;
2005 struct bfd_link_order *p;
2006 size_t outsymalloc;
2007 struct generic_write_global_symbol_info wginfo;
2009 bfd_get_outsymbols (abfd) = NULL;
2010 bfd_get_symcount (abfd) = 0;
2011 outsymalloc = 0;
2013 /* Mark all sections which will be included in the output file. */
2014 for (o = abfd->sections; o != NULL; o = o->next)
2015 for (p = o->map_head.link_order; p != NULL; p = p->next)
2016 if (p->type == bfd_indirect_link_order)
2017 p->u.indirect.section->linker_mark = TRUE;
2019 /* Build the output symbol table. */
2020 for (sub = info->input_bfds; sub != NULL; sub = sub->link_next)
2021 if (! _bfd_generic_link_output_symbols (abfd, sub, info, &outsymalloc))
2022 return FALSE;
2024 /* Accumulate the global symbols. */
2025 wginfo.info = info;
2026 wginfo.output_bfd = abfd;
2027 wginfo.psymalloc = &outsymalloc;
2028 _bfd_generic_link_hash_traverse (_bfd_generic_hash_table (info),
2029 _bfd_generic_link_write_global_symbol,
2030 &wginfo);
2032 /* Make sure we have a trailing NULL pointer on OUTSYMBOLS. We
2033 shouldn't really need one, since we have SYMCOUNT, but some old
2034 code still expects one. */
2035 if (! generic_add_output_symbol (abfd, &outsymalloc, NULL))
2036 return FALSE;
2038 if (info->relocatable)
2040 /* Allocate space for the output relocs for each section. */
2041 for (o = abfd->sections; o != NULL; o = o->next)
2043 o->reloc_count = 0;
2044 for (p = o->map_head.link_order; p != NULL; p = p->next)
2046 if (p->type == bfd_section_reloc_link_order
2047 || p->type == bfd_symbol_reloc_link_order)
2048 ++o->reloc_count;
2049 else if (p->type == bfd_indirect_link_order)
2051 asection *input_section;
2052 bfd *input_bfd;
2053 long relsize;
2054 arelent **relocs;
2055 asymbol **symbols;
2056 long reloc_count;
2058 input_section = p->u.indirect.section;
2059 input_bfd = input_section->owner;
2060 relsize = bfd_get_reloc_upper_bound (input_bfd,
2061 input_section);
2062 if (relsize < 0)
2063 return FALSE;
2064 relocs = bfd_malloc (relsize);
2065 if (!relocs && relsize != 0)
2066 return FALSE;
2067 symbols = _bfd_generic_link_get_symbols (input_bfd);
2068 reloc_count = bfd_canonicalize_reloc (input_bfd,
2069 input_section,
2070 relocs,
2071 symbols);
2072 free (relocs);
2073 if (reloc_count < 0)
2074 return FALSE;
2075 BFD_ASSERT ((unsigned long) reloc_count
2076 == input_section->reloc_count);
2077 o->reloc_count += reloc_count;
2080 if (o->reloc_count > 0)
2082 bfd_size_type amt;
2084 amt = o->reloc_count;
2085 amt *= sizeof (arelent *);
2086 o->orelocation = bfd_alloc (abfd, amt);
2087 if (!o->orelocation)
2088 return FALSE;
2089 o->flags |= SEC_RELOC;
2090 /* Reset the count so that it can be used as an index
2091 when putting in the output relocs. */
2092 o->reloc_count = 0;
2097 /* Handle all the link order information for the sections. */
2098 for (o = abfd->sections; o != NULL; o = o->next)
2100 for (p = o->map_head.link_order; p != NULL; p = p->next)
2102 switch (p->type)
2104 case bfd_section_reloc_link_order:
2105 case bfd_symbol_reloc_link_order:
2106 if (! _bfd_generic_reloc_link_order (abfd, info, o, p))
2107 return FALSE;
2108 break;
2109 case bfd_indirect_link_order:
2110 if (! default_indirect_link_order (abfd, info, o, p, TRUE))
2111 return FALSE;
2112 break;
2113 default:
2114 if (! _bfd_default_link_order (abfd, info, o, p))
2115 return FALSE;
2116 break;
2121 return TRUE;
2124 /* Add an output symbol to the output BFD. */
2126 static bfd_boolean
2127 generic_add_output_symbol (bfd *output_bfd, size_t *psymalloc, asymbol *sym)
2129 if (bfd_get_symcount (output_bfd) >= *psymalloc)
2131 asymbol **newsyms;
2132 bfd_size_type amt;
2134 if (*psymalloc == 0)
2135 *psymalloc = 124;
2136 else
2137 *psymalloc *= 2;
2138 amt = *psymalloc;
2139 amt *= sizeof (asymbol *);
2140 newsyms = bfd_realloc (bfd_get_outsymbols (output_bfd), amt);
2141 if (newsyms == NULL)
2142 return FALSE;
2143 bfd_get_outsymbols (output_bfd) = newsyms;
2146 bfd_get_outsymbols (output_bfd) [bfd_get_symcount (output_bfd)] = sym;
2147 if (sym != NULL)
2148 ++ bfd_get_symcount (output_bfd);
2150 return TRUE;
2153 /* Handle the symbols for an input BFD. */
2155 bfd_boolean
2156 _bfd_generic_link_output_symbols (bfd *output_bfd,
2157 bfd *input_bfd,
2158 struct bfd_link_info *info,
2159 size_t *psymalloc)
2161 asymbol **sym_ptr;
2162 asymbol **sym_end;
2164 if (! generic_link_read_symbols (input_bfd))
2165 return FALSE;
2167 /* Create a filename symbol if we are supposed to. */
2168 if (info->create_object_symbols_section != NULL)
2170 asection *sec;
2172 for (sec = input_bfd->sections; sec != NULL; sec = sec->next)
2174 if (sec->output_section == info->create_object_symbols_section)
2176 asymbol *newsym;
2178 newsym = bfd_make_empty_symbol (input_bfd);
2179 if (!newsym)
2180 return FALSE;
2181 newsym->name = input_bfd->filename;
2182 newsym->value = 0;
2183 newsym->flags = BSF_LOCAL | BSF_FILE;
2184 newsym->section = sec;
2186 if (! generic_add_output_symbol (output_bfd, psymalloc,
2187 newsym))
2188 return FALSE;
2190 break;
2195 /* Adjust the values of the globally visible symbols, and write out
2196 local symbols. */
2197 sym_ptr = _bfd_generic_link_get_symbols (input_bfd);
2198 sym_end = sym_ptr + _bfd_generic_link_get_symcount (input_bfd);
2199 for (; sym_ptr < sym_end; sym_ptr++)
2201 asymbol *sym;
2202 struct generic_link_hash_entry *h;
2203 bfd_boolean output;
2205 h = NULL;
2206 sym = *sym_ptr;
2207 if ((sym->flags & (BSF_INDIRECT
2208 | BSF_WARNING
2209 | BSF_GLOBAL
2210 | BSF_CONSTRUCTOR
2211 | BSF_WEAK)) != 0
2212 || bfd_is_und_section (bfd_get_section (sym))
2213 || bfd_is_com_section (bfd_get_section (sym))
2214 || bfd_is_ind_section (bfd_get_section (sym)))
2216 if (sym->udata.p != NULL)
2217 h = sym->udata.p;
2218 else if ((sym->flags & BSF_CONSTRUCTOR) != 0)
2220 /* This case normally means that the main linker code
2221 deliberately ignored this constructor symbol. We
2222 should just pass it through. This will screw up if
2223 the constructor symbol is from a different,
2224 non-generic, object file format, but the case will
2225 only arise when linking with -r, which will probably
2226 fail anyhow, since there will be no way to represent
2227 the relocs in the output format being used. */
2228 h = NULL;
2230 else if (bfd_is_und_section (bfd_get_section (sym)))
2231 h = ((struct generic_link_hash_entry *)
2232 bfd_wrapped_link_hash_lookup (output_bfd, info,
2233 bfd_asymbol_name (sym),
2234 FALSE, FALSE, TRUE));
2235 else
2236 h = _bfd_generic_link_hash_lookup (_bfd_generic_hash_table (info),
2237 bfd_asymbol_name (sym),
2238 FALSE, FALSE, TRUE);
2240 if (h != NULL)
2242 /* Force all references to this symbol to point to
2243 the same area in memory. It is possible that
2244 this routine will be called with a hash table
2245 other than a generic hash table, so we double
2246 check that. */
2247 if (info->hash->creator == input_bfd->xvec)
2249 if (h->sym != NULL)
2250 *sym_ptr = sym = h->sym;
2253 switch (h->root.type)
2255 default:
2256 case bfd_link_hash_new:
2257 abort ();
2258 case bfd_link_hash_undefined:
2259 break;
2260 case bfd_link_hash_undefweak:
2261 sym->flags |= BSF_WEAK;
2262 break;
2263 case bfd_link_hash_indirect:
2264 h = (struct generic_link_hash_entry *) h->root.u.i.link;
2265 /* fall through */
2266 case bfd_link_hash_defined:
2267 sym->flags |= BSF_GLOBAL;
2268 sym->flags &=~ BSF_CONSTRUCTOR;
2269 sym->value = h->root.u.def.value;
2270 sym->section = h->root.u.def.section;
2271 break;
2272 case bfd_link_hash_defweak:
2273 sym->flags |= BSF_WEAK;
2274 sym->flags &=~ BSF_CONSTRUCTOR;
2275 sym->value = h->root.u.def.value;
2276 sym->section = h->root.u.def.section;
2277 break;
2278 case bfd_link_hash_common:
2279 sym->value = h->root.u.c.size;
2280 sym->flags |= BSF_GLOBAL;
2281 if (! bfd_is_com_section (sym->section))
2283 BFD_ASSERT (bfd_is_und_section (sym->section));
2284 sym->section = bfd_com_section_ptr;
2286 /* We do not set the section of the symbol to
2287 h->root.u.c.p->section. That value was saved so
2288 that we would know where to allocate the symbol
2289 if it was defined. In this case the type is
2290 still bfd_link_hash_common, so we did not define
2291 it, so we do not want to use that section. */
2292 break;
2297 /* This switch is straight from the old code in
2298 write_file_locals in ldsym.c. */
2299 if (info->strip == strip_all
2300 || (info->strip == strip_some
2301 && bfd_hash_lookup (info->keep_hash, bfd_asymbol_name (sym),
2302 FALSE, FALSE) == NULL))
2303 output = FALSE;
2304 else if ((sym->flags & (BSF_GLOBAL | BSF_WEAK)) != 0)
2306 /* If this symbol is marked as occurring now, rather
2307 than at the end, output it now. This is used for
2308 COFF C_EXT FCN symbols. FIXME: There must be a
2309 better way. */
2310 if (bfd_asymbol_bfd (sym) == input_bfd
2311 && (sym->flags & BSF_NOT_AT_END) != 0)
2312 output = TRUE;
2313 else
2314 output = FALSE;
2316 else if (bfd_is_ind_section (sym->section))
2317 output = FALSE;
2318 else if ((sym->flags & BSF_DEBUGGING) != 0)
2320 if (info->strip == strip_none)
2321 output = TRUE;
2322 else
2323 output = FALSE;
2325 else if (bfd_is_und_section (sym->section)
2326 || bfd_is_com_section (sym->section))
2327 output = FALSE;
2328 else if ((sym->flags & BSF_LOCAL) != 0)
2330 if ((sym->flags & BSF_WARNING) != 0)
2331 output = FALSE;
2332 else
2334 switch (info->discard)
2336 default:
2337 case discard_all:
2338 output = FALSE;
2339 break;
2340 case discard_sec_merge:
2341 output = TRUE;
2342 if (info->relocatable
2343 || ! (sym->section->flags & SEC_MERGE))
2344 break;
2345 /* FALLTHROUGH */
2346 case discard_l:
2347 if (bfd_is_local_label (input_bfd, sym))
2348 output = FALSE;
2349 else
2350 output = TRUE;
2351 break;
2352 case discard_none:
2353 output = TRUE;
2354 break;
2358 else if ((sym->flags & BSF_CONSTRUCTOR))
2360 if (info->strip != strip_all)
2361 output = TRUE;
2362 else
2363 output = FALSE;
2365 else
2366 abort ();
2368 /* If this symbol is in a section which is not being included
2369 in the output file, then we don't want to output the
2370 symbol. */
2371 if (!bfd_is_abs_section (sym->section)
2372 && bfd_section_removed_from_list (output_bfd,
2373 sym->section->output_section))
2374 output = FALSE;
2376 if (output)
2378 if (! generic_add_output_symbol (output_bfd, psymalloc, sym))
2379 return FALSE;
2380 if (h != NULL)
2381 h->written = TRUE;
2385 return TRUE;
2388 /* Set the section and value of a generic BFD symbol based on a linker
2389 hash table entry. */
2391 static void
2392 set_symbol_from_hash (asymbol *sym, struct bfd_link_hash_entry *h)
2394 switch (h->type)
2396 default:
2397 abort ();
2398 break;
2399 case bfd_link_hash_new:
2400 /* This can happen when a constructor symbol is seen but we are
2401 not building constructors. */
2402 if (sym->section != NULL)
2404 BFD_ASSERT ((sym->flags & BSF_CONSTRUCTOR) != 0);
2406 else
2408 sym->flags |= BSF_CONSTRUCTOR;
2409 sym->section = bfd_abs_section_ptr;
2410 sym->value = 0;
2412 break;
2413 case bfd_link_hash_undefined:
2414 sym->section = bfd_und_section_ptr;
2415 sym->value = 0;
2416 break;
2417 case bfd_link_hash_undefweak:
2418 sym->section = bfd_und_section_ptr;
2419 sym->value = 0;
2420 sym->flags |= BSF_WEAK;
2421 break;
2422 case bfd_link_hash_defined:
2423 sym->section = h->u.def.section;
2424 sym->value = h->u.def.value;
2425 break;
2426 case bfd_link_hash_defweak:
2427 sym->flags |= BSF_WEAK;
2428 sym->section = h->u.def.section;
2429 sym->value = h->u.def.value;
2430 break;
2431 case bfd_link_hash_common:
2432 sym->value = h->u.c.size;
2433 if (sym->section == NULL)
2434 sym->section = bfd_com_section_ptr;
2435 else if (! bfd_is_com_section (sym->section))
2437 BFD_ASSERT (bfd_is_und_section (sym->section));
2438 sym->section = bfd_com_section_ptr;
2440 /* Do not set the section; see _bfd_generic_link_output_symbols. */
2441 break;
2442 case bfd_link_hash_indirect:
2443 case bfd_link_hash_warning:
2444 /* FIXME: What should we do here? */
2445 break;
2449 /* Write out a global symbol, if it hasn't already been written out.
2450 This is called for each symbol in the hash table. */
2452 bfd_boolean
2453 _bfd_generic_link_write_global_symbol (struct generic_link_hash_entry *h,
2454 void *data)
2456 struct generic_write_global_symbol_info *wginfo = data;
2457 asymbol *sym;
2459 if (h->root.type == bfd_link_hash_warning)
2460 h = (struct generic_link_hash_entry *) h->root.u.i.link;
2462 if (h->written)
2463 return TRUE;
2465 h->written = TRUE;
2467 if (wginfo->info->strip == strip_all
2468 || (wginfo->info->strip == strip_some
2469 && bfd_hash_lookup (wginfo->info->keep_hash, h->root.root.string,
2470 FALSE, FALSE) == NULL))
2471 return TRUE;
2473 if (h->sym != NULL)
2474 sym = h->sym;
2475 else
2477 sym = bfd_make_empty_symbol (wginfo->output_bfd);
2478 if (!sym)
2479 return FALSE;
2480 sym->name = h->root.root.string;
2481 sym->flags = 0;
2484 set_symbol_from_hash (sym, &h->root);
2486 sym->flags |= BSF_GLOBAL;
2488 if (! generic_add_output_symbol (wginfo->output_bfd, wginfo->psymalloc,
2489 sym))
2491 /* FIXME: No way to return failure. */
2492 abort ();
2495 return TRUE;
2498 /* Create a relocation. */
2500 bfd_boolean
2501 _bfd_generic_reloc_link_order (bfd *abfd,
2502 struct bfd_link_info *info,
2503 asection *sec,
2504 struct bfd_link_order *link_order)
2506 arelent *r;
2508 if (! info->relocatable)
2509 abort ();
2510 if (sec->orelocation == NULL)
2511 abort ();
2513 r = bfd_alloc (abfd, sizeof (arelent));
2514 if (r == NULL)
2515 return FALSE;
2517 r->address = link_order->offset;
2518 r->howto = bfd_reloc_type_lookup (abfd, link_order->u.reloc.p->reloc);
2519 if (r->howto == 0)
2521 bfd_set_error (bfd_error_bad_value);
2522 return FALSE;
2525 /* Get the symbol to use for the relocation. */
2526 if (link_order->type == bfd_section_reloc_link_order)
2527 r->sym_ptr_ptr = link_order->u.reloc.p->u.section->symbol_ptr_ptr;
2528 else
2530 struct generic_link_hash_entry *h;
2532 h = ((struct generic_link_hash_entry *)
2533 bfd_wrapped_link_hash_lookup (abfd, info,
2534 link_order->u.reloc.p->u.name,
2535 FALSE, FALSE, TRUE));
2536 if (h == NULL
2537 || ! h->written)
2539 if (! ((*info->callbacks->unattached_reloc)
2540 (info, link_order->u.reloc.p->u.name, NULL, NULL, 0)))
2541 return FALSE;
2542 bfd_set_error (bfd_error_bad_value);
2543 return FALSE;
2545 r->sym_ptr_ptr = &h->sym;
2548 /* If this is an inplace reloc, write the addend to the object file.
2549 Otherwise, store it in the reloc addend. */
2550 if (! r->howto->partial_inplace)
2551 r->addend = link_order->u.reloc.p->addend;
2552 else
2554 bfd_size_type size;
2555 bfd_reloc_status_type rstat;
2556 bfd_byte *buf;
2557 bfd_boolean ok;
2558 file_ptr loc;
2560 size = bfd_get_reloc_size (r->howto);
2561 buf = bfd_zmalloc (size);
2562 if (buf == NULL)
2563 return FALSE;
2564 rstat = _bfd_relocate_contents (r->howto, abfd,
2565 (bfd_vma) link_order->u.reloc.p->addend,
2566 buf);
2567 switch (rstat)
2569 case bfd_reloc_ok:
2570 break;
2571 default:
2572 case bfd_reloc_outofrange:
2573 abort ();
2574 case bfd_reloc_overflow:
2575 if (! ((*info->callbacks->reloc_overflow)
2576 (info, NULL,
2577 (link_order->type == bfd_section_reloc_link_order
2578 ? bfd_section_name (abfd, link_order->u.reloc.p->u.section)
2579 : link_order->u.reloc.p->u.name),
2580 r->howto->name, link_order->u.reloc.p->addend,
2581 NULL, NULL, 0)))
2583 free (buf);
2584 return FALSE;
2586 break;
2588 loc = link_order->offset * bfd_octets_per_byte (abfd);
2589 ok = bfd_set_section_contents (abfd, sec, buf, loc, size);
2590 free (buf);
2591 if (! ok)
2592 return FALSE;
2594 r->addend = 0;
2597 sec->orelocation[sec->reloc_count] = r;
2598 ++sec->reloc_count;
2600 return TRUE;
2603 /* Allocate a new link_order for a section. */
2605 struct bfd_link_order *
2606 bfd_new_link_order (bfd *abfd, asection *section)
2608 bfd_size_type amt = sizeof (struct bfd_link_order);
2609 struct bfd_link_order *new;
2611 new = bfd_zalloc (abfd, amt);
2612 if (!new)
2613 return NULL;
2615 new->type = bfd_undefined_link_order;
2617 if (section->map_tail.link_order != NULL)
2618 section->map_tail.link_order->next = new;
2619 else
2620 section->map_head.link_order = new;
2621 section->map_tail.link_order = new;
2623 return new;
2626 /* Default link order processing routine. Note that we can not handle
2627 the reloc_link_order types here, since they depend upon the details
2628 of how the particular backends generates relocs. */
2630 bfd_boolean
2631 _bfd_default_link_order (bfd *abfd,
2632 struct bfd_link_info *info,
2633 asection *sec,
2634 struct bfd_link_order *link_order)
2636 switch (link_order->type)
2638 case bfd_undefined_link_order:
2639 case bfd_section_reloc_link_order:
2640 case bfd_symbol_reloc_link_order:
2641 default:
2642 abort ();
2643 case bfd_indirect_link_order:
2644 return default_indirect_link_order (abfd, info, sec, link_order,
2645 FALSE);
2646 case bfd_data_link_order:
2647 return default_data_link_order (abfd, info, sec, link_order);
2651 /* Default routine to handle a bfd_data_link_order. */
2653 static bfd_boolean
2654 default_data_link_order (bfd *abfd,
2655 struct bfd_link_info *info ATTRIBUTE_UNUSED,
2656 asection *sec,
2657 struct bfd_link_order *link_order)
2659 bfd_size_type size;
2660 size_t fill_size;
2661 bfd_byte *fill;
2662 file_ptr loc;
2663 bfd_boolean result;
2665 BFD_ASSERT ((sec->flags & SEC_HAS_CONTENTS) != 0);
2667 size = link_order->size;
2668 if (size == 0)
2669 return TRUE;
2671 fill = link_order->u.data.contents;
2672 fill_size = link_order->u.data.size;
2673 if (fill_size != 0 && fill_size < size)
2675 bfd_byte *p;
2676 fill = bfd_malloc (size);
2677 if (fill == NULL)
2678 return FALSE;
2679 p = fill;
2680 if (fill_size == 1)
2681 memset (p, (int) link_order->u.data.contents[0], (size_t) size);
2682 else
2686 memcpy (p, link_order->u.data.contents, fill_size);
2687 p += fill_size;
2688 size -= fill_size;
2690 while (size >= fill_size);
2691 if (size != 0)
2692 memcpy (p, link_order->u.data.contents, (size_t) size);
2693 size = link_order->size;
2697 loc = link_order->offset * bfd_octets_per_byte (abfd);
2698 result = bfd_set_section_contents (abfd, sec, fill, loc, size);
2700 if (fill != link_order->u.data.contents)
2701 free (fill);
2702 return result;
2705 /* Default routine to handle a bfd_indirect_link_order. */
2707 static bfd_boolean
2708 default_indirect_link_order (bfd *output_bfd,
2709 struct bfd_link_info *info,
2710 asection *output_section,
2711 struct bfd_link_order *link_order,
2712 bfd_boolean generic_linker)
2714 asection *input_section;
2715 bfd *input_bfd;
2716 bfd_byte *contents = NULL;
2717 bfd_byte *new_contents;
2718 bfd_size_type sec_size;
2719 file_ptr loc;
2721 BFD_ASSERT ((output_section->flags & SEC_HAS_CONTENTS) != 0);
2723 input_section = link_order->u.indirect.section;
2724 input_bfd = input_section->owner;
2725 if (input_section->size == 0)
2726 return TRUE;
2728 BFD_ASSERT (input_section->output_section == output_section);
2729 BFD_ASSERT (input_section->output_offset == link_order->offset);
2730 BFD_ASSERT (input_section->size == link_order->size);
2732 if (info->relocatable
2733 && input_section->reloc_count > 0
2734 && output_section->orelocation == NULL)
2736 /* Space has not been allocated for the output relocations.
2737 This can happen when we are called by a specific backend
2738 because somebody is attempting to link together different
2739 types of object files. Handling this case correctly is
2740 difficult, and sometimes impossible. */
2741 (*_bfd_error_handler)
2742 (_("Attempt to do relocatable link with %s input and %s output"),
2743 bfd_get_target (input_bfd), bfd_get_target (output_bfd));
2744 bfd_set_error (bfd_error_wrong_format);
2745 return FALSE;
2748 if (! generic_linker)
2750 asymbol **sympp;
2751 asymbol **symppend;
2753 /* Get the canonical symbols. The generic linker will always
2754 have retrieved them by this point, but we are being called by
2755 a specific linker, presumably because we are linking
2756 different types of object files together. */
2757 if (! generic_link_read_symbols (input_bfd))
2758 return FALSE;
2760 /* Since we have been called by a specific linker, rather than
2761 the generic linker, the values of the symbols will not be
2762 right. They will be the values as seen in the input file,
2763 not the values of the final link. We need to fix them up
2764 before we can relocate the section. */
2765 sympp = _bfd_generic_link_get_symbols (input_bfd);
2766 symppend = sympp + _bfd_generic_link_get_symcount (input_bfd);
2767 for (; sympp < symppend; sympp++)
2769 asymbol *sym;
2770 struct bfd_link_hash_entry *h;
2772 sym = *sympp;
2774 if ((sym->flags & (BSF_INDIRECT
2775 | BSF_WARNING
2776 | BSF_GLOBAL
2777 | BSF_CONSTRUCTOR
2778 | BSF_WEAK)) != 0
2779 || bfd_is_und_section (bfd_get_section (sym))
2780 || bfd_is_com_section (bfd_get_section (sym))
2781 || bfd_is_ind_section (bfd_get_section (sym)))
2783 /* sym->udata may have been set by
2784 generic_link_add_symbol_list. */
2785 if (sym->udata.p != NULL)
2786 h = sym->udata.p;
2787 else if (bfd_is_und_section (bfd_get_section (sym)))
2788 h = bfd_wrapped_link_hash_lookup (output_bfd, info,
2789 bfd_asymbol_name (sym),
2790 FALSE, FALSE, TRUE);
2791 else
2792 h = bfd_link_hash_lookup (info->hash,
2793 bfd_asymbol_name (sym),
2794 FALSE, FALSE, TRUE);
2795 if (h != NULL)
2796 set_symbol_from_hash (sym, h);
2801 /* Get and relocate the section contents. */
2802 sec_size = (input_section->rawsize > input_section->size
2803 ? input_section->rawsize
2804 : input_section->size);
2805 contents = bfd_malloc (sec_size);
2806 if (contents == NULL && sec_size != 0)
2807 goto error_return;
2808 new_contents = (bfd_get_relocated_section_contents
2809 (output_bfd, info, link_order, contents, info->relocatable,
2810 _bfd_generic_link_get_symbols (input_bfd)));
2811 if (!new_contents)
2812 goto error_return;
2814 /* Output the section contents. */
2815 loc = input_section->output_offset * bfd_octets_per_byte (output_bfd);
2816 if (! bfd_set_section_contents (output_bfd, output_section,
2817 new_contents, loc, input_section->size))
2818 goto error_return;
2820 if (contents != NULL)
2821 free (contents);
2822 return TRUE;
2824 error_return:
2825 if (contents != NULL)
2826 free (contents);
2827 return FALSE;
2830 /* A little routine to count the number of relocs in a link_order
2831 list. */
2833 unsigned int
2834 _bfd_count_link_order_relocs (struct bfd_link_order *link_order)
2836 register unsigned int c;
2837 register struct bfd_link_order *l;
2839 c = 0;
2840 for (l = link_order; l != NULL; l = l->next)
2842 if (l->type == bfd_section_reloc_link_order
2843 || l->type == bfd_symbol_reloc_link_order)
2844 ++c;
2847 return c;
2851 FUNCTION
2852 bfd_link_split_section
2854 SYNOPSIS
2855 bfd_boolean bfd_link_split_section (bfd *abfd, asection *sec);
2857 DESCRIPTION
2858 Return nonzero if @var{sec} should be split during a
2859 reloceatable or final link.
2861 .#define bfd_link_split_section(abfd, sec) \
2862 . BFD_SEND (abfd, _bfd_link_split_section, (abfd, sec))
2867 bfd_boolean
2868 _bfd_generic_link_split_section (bfd *abfd ATTRIBUTE_UNUSED,
2869 asection *sec ATTRIBUTE_UNUSED)
2871 return FALSE;
2875 FUNCTION
2876 bfd_section_already_linked
2878 SYNOPSIS
2879 void bfd_section_already_linked (bfd *abfd, asection *sec,
2880 struct bfd_link_info *info);
2882 DESCRIPTION
2883 Check if @var{sec} has been already linked during a reloceatable
2884 or final link.
2886 .#define bfd_section_already_linked(abfd, sec, info) \
2887 . BFD_SEND (abfd, _section_already_linked, (abfd, sec, info))
2892 /* Sections marked with the SEC_LINK_ONCE flag should only be linked
2893 once into the output. This routine checks each section, and
2894 arrange to discard it if a section of the same name has already
2895 been linked. This code assumes that all relevant sections have the
2896 SEC_LINK_ONCE flag set; that is, it does not depend solely upon the
2897 section name. bfd_section_already_linked is called via
2898 bfd_map_over_sections. */
2900 /* The hash table. */
2902 static struct bfd_hash_table _bfd_section_already_linked_table;
2904 /* Support routines for the hash table used by section_already_linked,
2905 initialize the table, traverse, lookup, fill in an entry and remove
2906 the table. */
2908 void
2909 bfd_section_already_linked_table_traverse
2910 (bfd_boolean (*func) (struct bfd_section_already_linked_hash_entry *,
2911 void *), void *info)
2913 bfd_hash_traverse (&_bfd_section_already_linked_table,
2914 (bfd_boolean (*) (struct bfd_hash_entry *,
2915 void *)) func,
2916 info);
2919 struct bfd_section_already_linked_hash_entry *
2920 bfd_section_already_linked_table_lookup (const char *name)
2922 return ((struct bfd_section_already_linked_hash_entry *)
2923 bfd_hash_lookup (&_bfd_section_already_linked_table, name,
2924 TRUE, FALSE));
2927 void
2928 bfd_section_already_linked_table_insert
2929 (struct bfd_section_already_linked_hash_entry *already_linked_list,
2930 asection *sec)
2932 struct bfd_section_already_linked *l;
2934 /* Allocate the memory from the same obstack as the hash table is
2935 kept in. */
2936 l = bfd_hash_allocate (&_bfd_section_already_linked_table, sizeof *l);
2937 l->sec = sec;
2938 l->next = already_linked_list->entry;
2939 already_linked_list->entry = l;
2942 static struct bfd_hash_entry *
2943 already_linked_newfunc (struct bfd_hash_entry *entry ATTRIBUTE_UNUSED,
2944 struct bfd_hash_table *table,
2945 const char *string ATTRIBUTE_UNUSED)
2947 struct bfd_section_already_linked_hash_entry *ret =
2948 bfd_hash_allocate (table, sizeof *ret);
2950 ret->entry = NULL;
2952 return &ret->root;
2955 bfd_boolean
2956 bfd_section_already_linked_table_init (void)
2958 return bfd_hash_table_init_n (&_bfd_section_already_linked_table,
2959 already_linked_newfunc,
2960 sizeof (struct bfd_section_already_linked_hash_entry),
2961 42);
2964 void
2965 bfd_section_already_linked_table_free (void)
2967 bfd_hash_table_free (&_bfd_section_already_linked_table);
2970 /* This is used on non-ELF inputs. */
2972 void
2973 _bfd_generic_section_already_linked (bfd *abfd, asection *sec,
2974 struct bfd_link_info *info ATTRIBUTE_UNUSED)
2976 flagword flags;
2977 const char *name;
2978 struct bfd_section_already_linked *l;
2979 struct bfd_section_already_linked_hash_entry *already_linked_list;
2981 flags = sec->flags;
2982 if ((flags & SEC_LINK_ONCE) == 0)
2983 return;
2985 /* FIXME: When doing a relocatable link, we may have trouble
2986 copying relocations in other sections that refer to local symbols
2987 in the section being discarded. Those relocations will have to
2988 be converted somehow; as of this writing I'm not sure that any of
2989 the backends handle that correctly.
2991 It is tempting to instead not discard link once sections when
2992 doing a relocatable link (technically, they should be discarded
2993 whenever we are building constructors). However, that fails,
2994 because the linker winds up combining all the link once sections
2995 into a single large link once section, which defeats the purpose
2996 of having link once sections in the first place. */
2998 name = bfd_get_section_name (abfd, sec);
3000 already_linked_list = bfd_section_already_linked_table_lookup (name);
3002 for (l = already_linked_list->entry; l != NULL; l = l->next)
3004 bfd_boolean skip = FALSE;
3005 struct coff_comdat_info *s_comdat
3006 = bfd_coff_get_comdat_section (abfd, sec);
3007 struct coff_comdat_info *l_comdat
3008 = bfd_coff_get_comdat_section (l->sec->owner, l->sec);
3010 /* We may have 3 different sections on the list: group section,
3011 comdat section and linkonce section. SEC may be a linkonce or
3012 comdat section. We always ignore group section. For non-COFF
3013 inputs, we also ignore comdat section.
3015 FIXME: Is that safe to match a linkonce section with a comdat
3016 section for COFF inputs? */
3017 if ((l->sec->flags & SEC_GROUP) != 0)
3018 skip = TRUE;
3019 else if (bfd_get_flavour (abfd) == bfd_target_coff_flavour)
3021 if (s_comdat != NULL
3022 && l_comdat != NULL
3023 && strcmp (s_comdat->name, l_comdat->name) != 0)
3024 skip = TRUE;
3026 else if (l_comdat != NULL)
3027 skip = TRUE;
3029 if (!skip)
3031 /* The section has already been linked. See if we should
3032 issue a warning. */
3033 switch (flags & SEC_LINK_DUPLICATES)
3035 default:
3036 abort ();
3038 case SEC_LINK_DUPLICATES_DISCARD:
3039 break;
3041 case SEC_LINK_DUPLICATES_ONE_ONLY:
3042 (*_bfd_error_handler)
3043 (_("%B: warning: ignoring duplicate section `%A'\n"),
3044 abfd, sec);
3045 break;
3047 case SEC_LINK_DUPLICATES_SAME_CONTENTS:
3048 /* FIXME: We should really dig out the contents of both
3049 sections and memcmp them. The COFF/PE spec says that
3050 the Microsoft linker does not implement this
3051 correctly, so I'm not going to bother doing it
3052 either. */
3053 /* Fall through. */
3054 case SEC_LINK_DUPLICATES_SAME_SIZE:
3055 if (sec->size != l->sec->size)
3056 (*_bfd_error_handler)
3057 (_("%B: warning: duplicate section `%A' has different size\n"),
3058 abfd, sec);
3059 break;
3062 /* Set the output_section field so that lang_add_section
3063 does not create a lang_input_section structure for this
3064 section. Since there might be a symbol in the section
3065 being discarded, we must retain a pointer to the section
3066 which we are really going to use. */
3067 sec->output_section = bfd_abs_section_ptr;
3068 sec->kept_section = l->sec;
3070 return;
3074 /* This is the first section with this name. Record it. */
3075 bfd_section_already_linked_table_insert (already_linked_list, sec);
3078 /* Convert symbols in excluded output sections to use a kept section. */
3080 static bfd_boolean
3081 fix_syms (struct bfd_link_hash_entry *h, void *data)
3083 bfd *obfd = (bfd *) data;
3085 if (h->type == bfd_link_hash_warning)
3086 h = h->u.i.link;
3088 if (h->type == bfd_link_hash_defined
3089 || h->type == bfd_link_hash_defweak)
3091 asection *s = h->u.def.section;
3092 if (s != NULL
3093 && s->output_section != NULL
3094 && (s->output_section->flags & SEC_EXCLUDE) != 0
3095 && bfd_section_removed_from_list (obfd, s->output_section))
3097 asection *op, *op1;
3099 h->u.def.value += s->output_offset + s->output_section->vma;
3101 /* Find preceding kept section. */
3102 for (op1 = s->output_section->prev; op1 != NULL; op1 = op1->prev)
3103 if ((op1->flags & SEC_EXCLUDE) == 0
3104 && !bfd_section_removed_from_list (obfd, op1))
3105 break;
3107 /* Find following kept section. Start at prev->next because
3108 other sections may have been added after S was removed. */
3109 if (s->output_section->prev != NULL)
3110 op = s->output_section->prev->next;
3111 else
3112 op = s->output_section->owner->sections;
3113 for (; op != NULL; op = op->next)
3114 if ((op->flags & SEC_EXCLUDE) == 0
3115 && !bfd_section_removed_from_list (obfd, op))
3116 break;
3118 /* Choose better of two sections, based on flags. The idea
3119 is to choose a section that will be in the same segment
3120 as S would have been if it was kept. */
3121 if (op1 == NULL)
3123 if (op == NULL)
3124 op = bfd_abs_section_ptr;
3126 else if (op == NULL)
3127 op = op1;
3128 else if (((op1->flags ^ op->flags)
3129 & (SEC_ALLOC | SEC_THREAD_LOCAL)) != 0)
3131 if (((op->flags ^ s->flags)
3132 & (SEC_ALLOC | SEC_THREAD_LOCAL)) != 0)
3133 op = op1;
3135 else if (((op1->flags ^ op->flags) & SEC_READONLY) != 0)
3137 if (((op->flags ^ s->flags) & SEC_READONLY) != 0)
3138 op = op1;
3140 else if (((op1->flags ^ op->flags) & SEC_CODE) != 0)
3142 if (((op->flags ^ s->flags) & SEC_CODE) != 0)
3143 op = op1;
3145 else
3147 /* Flags we care about are the same. Prefer the following
3148 section if that will result in a positive valued sym. */
3149 if (h->u.def.value < op->vma)
3150 op = op1;
3153 h->u.def.value -= op->vma;
3154 h->u.def.section = op;
3158 return TRUE;
3161 void
3162 _bfd_fix_excluded_sec_syms (bfd *obfd, struct bfd_link_info *info)
3164 bfd_link_hash_traverse (info->hash, fix_syms, obfd);