1 /* linker.c -- BFD linker routines
2 Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
3 2003, 2004, 2005, 2006, 2007
4 Free Software Foundation, Inc.
5 Written by Steve Chamberlain and Ian Lance Taylor, Cygnus Support
7 This file is part of BFD, the Binary File Descriptor library.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program; if not, write to the Free Software
21 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
22 MA 02110-1301, USA. */
35 The linker uses three special entry points in the BFD target
36 vector. It is not necessary to write special routines for
37 these entry points when creating a new BFD back end, since
38 generic versions are provided. However, writing them can
39 speed up linking and make it use significantly less runtime
42 The first routine creates a hash table used by the other
43 routines. The second routine adds the symbols from an object
44 file to the hash table. The third routine takes all the
45 object files and links them together to create the output
46 file. These routines are designed so that the linker proper
47 does not need to know anything about the symbols in the object
48 files that it is linking. The linker merely arranges the
49 sections as directed by the linker script and lets BFD handle
50 the details of symbols and relocs.
52 The second routine and third routines are passed a pointer to
53 a <<struct bfd_link_info>> structure (defined in
54 <<bfdlink.h>>) which holds information relevant to the link,
55 including the linker hash table (which was created by the
56 first routine) and a set of callback functions to the linker
59 The generic linker routines are in <<linker.c>>, and use the
60 header file <<genlink.h>>. As of this writing, the only back
61 ends which have implemented versions of these routines are
62 a.out (in <<aoutx.h>>) and ECOFF (in <<ecoff.c>>). The a.out
63 routines are used as examples throughout this section.
66 @* Creating a Linker Hash Table::
67 @* Adding Symbols to the Hash Table::
68 @* Performing the Final Link::
72 Creating a Linker Hash Table, Adding Symbols to the Hash Table, Linker Functions, Linker Functions
74 Creating a linker hash table
76 @cindex _bfd_link_hash_table_create in target vector
77 @cindex target vector (_bfd_link_hash_table_create)
78 The linker routines must create a hash table, which must be
79 derived from <<struct bfd_link_hash_table>> described in
80 <<bfdlink.c>>. @xref{Hash Tables}, for information on how to
81 create a derived hash table. This entry point is called using
82 the target vector of the linker output file.
84 The <<_bfd_link_hash_table_create>> entry point must allocate
85 and initialize an instance of the desired hash table. If the
86 back end does not require any additional information to be
87 stored with the entries in the hash table, the entry point may
88 simply create a <<struct bfd_link_hash_table>>. Most likely,
89 however, some additional information will be needed.
91 For example, with each entry in the hash table the a.out
92 linker keeps the index the symbol has in the final output file
93 (this index number is used so that when doing a relocatable
94 link the symbol index used in the output file can be quickly
95 filled in when copying over a reloc). The a.out linker code
96 defines the required structures and functions for a hash table
97 derived from <<struct bfd_link_hash_table>>. The a.out linker
98 hash table is created by the function
99 <<NAME(aout,link_hash_table_create)>>; it simply allocates
100 space for the hash table, initializes it, and returns a
103 When writing the linker routines for a new back end, you will
104 generally not know exactly which fields will be required until
105 you have finished. You should simply create a new hash table
106 which defines no additional fields, and then simply add fields
107 as they become necessary.
110 Adding Symbols to the Hash Table, Performing the Final Link, Creating a Linker Hash Table, Linker Functions
112 Adding symbols to the hash table
114 @cindex _bfd_link_add_symbols in target vector
115 @cindex target vector (_bfd_link_add_symbols)
116 The linker proper will call the <<_bfd_link_add_symbols>>
117 entry point for each object file or archive which is to be
118 linked (typically these are the files named on the command
119 line, but some may also come from the linker script). The
120 entry point is responsible for examining the file. For an
121 object file, BFD must add any relevant symbol information to
122 the hash table. For an archive, BFD must determine which
123 elements of the archive should be used and adding them to the
126 The a.out version of this entry point is
127 <<NAME(aout,link_add_symbols)>>.
130 @* Differing file formats::
131 @* Adding symbols from an object file::
132 @* Adding symbols from an archive::
136 Differing file formats, Adding symbols from an object file, Adding Symbols to the Hash Table, Adding Symbols to the Hash Table
138 Differing file formats
140 Normally all the files involved in a link will be of the same
141 format, but it is also possible to link together different
142 format object files, and the back end must support that. The
143 <<_bfd_link_add_symbols>> entry point is called via the target
144 vector of the file to be added. This has an important
145 consequence: the function may not assume that the hash table
146 is the type created by the corresponding
147 <<_bfd_link_hash_table_create>> vector. All the
148 <<_bfd_link_add_symbols>> function can assume about the hash
149 table is that it is derived from <<struct
150 bfd_link_hash_table>>.
152 Sometimes the <<_bfd_link_add_symbols>> function must store
153 some information in the hash table entry to be used by the
154 <<_bfd_final_link>> function. In such a case the <<creator>>
155 field of the hash table must be checked to make sure that the
156 hash table was created by an object file of the same format.
158 The <<_bfd_final_link>> routine must be prepared to handle a
159 hash entry without any extra information added by the
160 <<_bfd_link_add_symbols>> function. A hash entry without
161 extra information will also occur when the linker script
162 directs the linker to create a symbol. Note that, regardless
163 of how a hash table entry is added, all the fields will be
164 initialized to some sort of null value by the hash table entry
165 initialization function.
167 See <<ecoff_link_add_externals>> for an example of how to
168 check the <<creator>> field before saving information (in this
169 case, the ECOFF external symbol debugging information) in a
173 Adding symbols from an object file, Adding symbols from an archive, Differing file formats, Adding Symbols to the Hash Table
175 Adding symbols from an object file
177 When the <<_bfd_link_add_symbols>> routine is passed an object
178 file, it must add all externally visible symbols in that
179 object file to the hash table. The actual work of adding the
180 symbol to the hash table is normally handled by the function
181 <<_bfd_generic_link_add_one_symbol>>. The
182 <<_bfd_link_add_symbols>> routine is responsible for reading
183 all the symbols from the object file and passing the correct
184 information to <<_bfd_generic_link_add_one_symbol>>.
186 The <<_bfd_link_add_symbols>> routine should not use
187 <<bfd_canonicalize_symtab>> to read the symbols. The point of
188 providing this routine is to avoid the overhead of converting
189 the symbols into generic <<asymbol>> structures.
191 @findex _bfd_generic_link_add_one_symbol
192 <<_bfd_generic_link_add_one_symbol>> handles the details of
193 combining common symbols, warning about multiple definitions,
194 and so forth. It takes arguments which describe the symbol to
195 add, notably symbol flags, a section, and an offset. The
196 symbol flags include such things as <<BSF_WEAK>> or
197 <<BSF_INDIRECT>>. The section is a section in the object
198 file, or something like <<bfd_und_section_ptr>> for an undefined
199 symbol or <<bfd_com_section_ptr>> for a common symbol.
201 If the <<_bfd_final_link>> routine is also going to need to
202 read the symbol information, the <<_bfd_link_add_symbols>>
203 routine should save it somewhere attached to the object file
204 BFD. However, the information should only be saved if the
205 <<keep_memory>> field of the <<info>> argument is TRUE, so
206 that the <<-no-keep-memory>> linker switch is effective.
208 The a.out function which adds symbols from an object file is
209 <<aout_link_add_object_symbols>>, and most of the interesting
210 work is in <<aout_link_add_symbols>>. The latter saves
211 pointers to the hash tables entries created by
212 <<_bfd_generic_link_add_one_symbol>> indexed by symbol number,
213 so that the <<_bfd_final_link>> routine does not have to call
214 the hash table lookup routine to locate the entry.
217 Adding symbols from an archive, , Adding symbols from an object file, Adding Symbols to the Hash Table
219 Adding symbols from an archive
221 When the <<_bfd_link_add_symbols>> routine is passed an
222 archive, it must look through the symbols defined by the
223 archive and decide which elements of the archive should be
224 included in the link. For each such element it must call the
225 <<add_archive_element>> linker callback, and it must add the
226 symbols from the object file to the linker hash table.
228 @findex _bfd_generic_link_add_archive_symbols
229 In most cases the work of looking through the symbols in the
230 archive should be done by the
231 <<_bfd_generic_link_add_archive_symbols>> function. This
232 function builds a hash table from the archive symbol table and
233 looks through the list of undefined symbols to see which
234 elements should be included.
235 <<_bfd_generic_link_add_archive_symbols>> is passed a function
236 to call to make the final decision about adding an archive
237 element to the link and to do the actual work of adding the
238 symbols to the linker hash table.
240 The function passed to
241 <<_bfd_generic_link_add_archive_symbols>> must read the
242 symbols of the archive element and decide whether the archive
243 element should be included in the link. If the element is to
244 be included, the <<add_archive_element>> linker callback
245 routine must be called with the element as an argument, and
246 the elements symbols must be added to the linker hash table
247 just as though the element had itself been passed to the
248 <<_bfd_link_add_symbols>> function.
250 When the a.out <<_bfd_link_add_symbols>> function receives an
251 archive, it calls <<_bfd_generic_link_add_archive_symbols>>
252 passing <<aout_link_check_archive_element>> as the function
253 argument. <<aout_link_check_archive_element>> calls
254 <<aout_link_check_ar_symbols>>. If the latter decides to add
255 the element (an element is only added if it provides a real,
256 non-common, definition for a previously undefined or common
257 symbol) it calls the <<add_archive_element>> callback and then
258 <<aout_link_check_archive_element>> calls
259 <<aout_link_add_symbols>> to actually add the symbols to the
262 The ECOFF back end is unusual in that it does not normally
263 call <<_bfd_generic_link_add_archive_symbols>>, because ECOFF
264 archives already contain a hash table of symbols. The ECOFF
265 back end searches the archive itself to avoid the overhead of
266 creating a new hash table.
269 Performing the Final Link, , Adding Symbols to the Hash Table, Linker Functions
271 Performing the final link
273 @cindex _bfd_link_final_link in target vector
274 @cindex target vector (_bfd_final_link)
275 When all the input files have been processed, the linker calls
276 the <<_bfd_final_link>> entry point of the output BFD. This
277 routine is responsible for producing the final output file,
278 which has several aspects. It must relocate the contents of
279 the input sections and copy the data into the output sections.
280 It must build an output symbol table including any local
281 symbols from the input files and the global symbols from the
282 hash table. When producing relocatable output, it must
283 modify the input relocs and write them into the output file.
284 There may also be object format dependent work to be done.
286 The linker will also call the <<write_object_contents>> entry
287 point when the BFD is closed. The two entry points must work
288 together in order to produce the correct output file.
290 The details of how this works are inevitably dependent upon
291 the specific object file format. The a.out
292 <<_bfd_final_link>> routine is <<NAME(aout,final_link)>>.
295 @* Information provided by the linker::
296 @* Relocating the section contents::
297 @* Writing the symbol table::
301 Information provided by the linker, Relocating the section contents, Performing the Final Link, Performing the Final Link
303 Information provided by the linker
305 Before the linker calls the <<_bfd_final_link>> entry point,
306 it sets up some data structures for the function to use.
308 The <<input_bfds>> field of the <<bfd_link_info>> structure
309 will point to a list of all the input files included in the
310 link. These files are linked through the <<link_next>> field
311 of the <<bfd>> structure.
313 Each section in the output file will have a list of
314 <<link_order>> structures attached to the <<map_head.link_order>>
315 field (the <<link_order>> structure is defined in
316 <<bfdlink.h>>). These structures describe how to create the
317 contents of the output section in terms of the contents of
318 various input sections, fill constants, and, eventually, other
319 types of information. They also describe relocs that must be
320 created by the BFD backend, but do not correspond to any input
321 file; this is used to support -Ur, which builds constructors
322 while generating a relocatable object file.
325 Relocating the section contents, Writing the symbol table, Information provided by the linker, Performing the Final Link
327 Relocating the section contents
329 The <<_bfd_final_link>> function should look through the
330 <<link_order>> structures attached to each section of the
331 output file. Each <<link_order>> structure should either be
332 handled specially, or it should be passed to the function
333 <<_bfd_default_link_order>> which will do the right thing
334 (<<_bfd_default_link_order>> is defined in <<linker.c>>).
336 For efficiency, a <<link_order>> of type
337 <<bfd_indirect_link_order>> whose associated section belongs
338 to a BFD of the same format as the output BFD must be handled
339 specially. This type of <<link_order>> describes part of an
340 output section in terms of a section belonging to one of the
341 input files. The <<_bfd_final_link>> function should read the
342 contents of the section and any associated relocs, apply the
343 relocs to the section contents, and write out the modified
344 section contents. If performing a relocatable link, the
345 relocs themselves must also be modified and written out.
347 @findex _bfd_relocate_contents
348 @findex _bfd_final_link_relocate
349 The functions <<_bfd_relocate_contents>> and
350 <<_bfd_final_link_relocate>> provide some general support for
351 performing the actual relocations, notably overflow checking.
352 Their arguments include information about the symbol the
353 relocation is against and a <<reloc_howto_type>> argument
354 which describes the relocation to perform. These functions
355 are defined in <<reloc.c>>.
357 The a.out function which handles reading, relocating, and
358 writing section contents is <<aout_link_input_section>>. The
359 actual relocation is done in <<aout_link_input_section_std>>
360 and <<aout_link_input_section_ext>>.
363 Writing the symbol table, , Relocating the section contents, Performing the Final Link
365 Writing the symbol table
367 The <<_bfd_final_link>> function must gather all the symbols
368 in the input files and write them out. It must also write out
369 all the symbols in the global hash table. This must be
370 controlled by the <<strip>> and <<discard>> fields of the
371 <<bfd_link_info>> structure.
373 The local symbols of the input files will not have been
374 entered into the linker hash table. The <<_bfd_final_link>>
375 routine must consider each input file and include the symbols
376 in the output file. It may be convenient to do this when
377 looking through the <<link_order>> structures, or it may be
378 done by stepping through the <<input_bfds>> list.
380 The <<_bfd_final_link>> routine must also traverse the global
381 hash table to gather all the externally visible symbols. It
382 is possible that most of the externally visible symbols may be
383 written out when considering the symbols of each input file,
384 but it is still necessary to traverse the hash table since the
385 linker script may have defined some symbols that are not in
386 any of the input files.
388 The <<strip>> field of the <<bfd_link_info>> structure
389 controls which symbols are written out. The possible values
390 are listed in <<bfdlink.h>>. If the value is <<strip_some>>,
391 then the <<keep_hash>> field of the <<bfd_link_info>>
392 structure is a hash table of symbols to keep; each symbol
393 should be looked up in this hash table, and only symbols which
394 are present should be included in the output file.
396 If the <<strip>> field of the <<bfd_link_info>> structure
397 permits local symbols to be written out, the <<discard>> field
398 is used to further controls which local symbols are included
399 in the output file. If the value is <<discard_l>>, then all
400 local symbols which begin with a certain prefix are discarded;
401 this is controlled by the <<bfd_is_local_label_name>> entry point.
403 The a.out backend handles symbols by calling
404 <<aout_link_write_symbols>> on each input BFD and then
405 traversing the global hash table with the function
406 <<aout_link_write_other_symbol>>. It builds a string table
407 while writing out the symbols, which is written to the output
408 file at the end of <<NAME(aout,final_link)>>.
411 static bfd_boolean generic_link_add_object_symbols
412 (bfd
*, struct bfd_link_info
*, bfd_boolean collect
);
413 static bfd_boolean generic_link_add_symbols
414 (bfd
*, struct bfd_link_info
*, bfd_boolean
);
415 static bfd_boolean generic_link_check_archive_element_no_collect
416 (bfd
*, struct bfd_link_info
*, bfd_boolean
*);
417 static bfd_boolean generic_link_check_archive_element_collect
418 (bfd
*, struct bfd_link_info
*, bfd_boolean
*);
419 static bfd_boolean generic_link_check_archive_element
420 (bfd
*, struct bfd_link_info
*, bfd_boolean
*, bfd_boolean
);
421 static bfd_boolean generic_link_add_symbol_list
422 (bfd
*, struct bfd_link_info
*, bfd_size_type count
, asymbol
**,
424 static bfd_boolean generic_add_output_symbol
425 (bfd
*, size_t *psymalloc
, asymbol
*);
426 static bfd_boolean default_data_link_order
427 (bfd
*, struct bfd_link_info
*, asection
*, struct bfd_link_order
*);
428 static bfd_boolean default_indirect_link_order
429 (bfd
*, struct bfd_link_info
*, asection
*, struct bfd_link_order
*,
432 /* The link hash table structure is defined in bfdlink.h. It provides
433 a base hash table which the backend specific hash tables are built
436 /* Routine to create an entry in the link hash table. */
438 struct bfd_hash_entry
*
439 _bfd_link_hash_newfunc (struct bfd_hash_entry
*entry
,
440 struct bfd_hash_table
*table
,
443 /* Allocate the structure if it has not already been allocated by a
447 entry
= bfd_hash_allocate (table
, sizeof (struct bfd_link_hash_entry
));
452 /* Call the allocation method of the superclass. */
453 entry
= bfd_hash_newfunc (entry
, table
, string
);
456 struct bfd_link_hash_entry
*h
= (struct bfd_link_hash_entry
*) entry
;
458 /* Initialize the local fields. */
459 h
->type
= bfd_link_hash_new
;
460 memset (&h
->u
.undef
.next
, 0,
461 (sizeof (struct bfd_link_hash_entry
)
462 - offsetof (struct bfd_link_hash_entry
, u
.undef
.next
)));
468 /* Initialize a link hash table. The BFD argument is the one
469 responsible for creating this table. */
472 _bfd_link_hash_table_init
473 (struct bfd_link_hash_table
*table
,
475 struct bfd_hash_entry
*(*newfunc
) (struct bfd_hash_entry
*,
476 struct bfd_hash_table
*,
478 unsigned int entsize
)
480 table
->creator
= abfd
->xvec
;
481 table
->undefs
= NULL
;
482 table
->undefs_tail
= NULL
;
483 table
->type
= bfd_link_generic_hash_table
;
485 return bfd_hash_table_init (&table
->table
, newfunc
, entsize
);
488 /* Look up a symbol in a link hash table. If follow is TRUE, we
489 follow bfd_link_hash_indirect and bfd_link_hash_warning links to
492 struct bfd_link_hash_entry
*
493 bfd_link_hash_lookup (struct bfd_link_hash_table
*table
,
499 struct bfd_link_hash_entry
*ret
;
501 ret
= ((struct bfd_link_hash_entry
*)
502 bfd_hash_lookup (&table
->table
, string
, create
, copy
));
504 if (follow
&& ret
!= NULL
)
506 while (ret
->type
== bfd_link_hash_indirect
507 || ret
->type
== bfd_link_hash_warning
)
514 /* Look up a symbol in the main linker hash table if the symbol might
515 be wrapped. This should only be used for references to an
516 undefined symbol, not for definitions of a symbol. */
518 struct bfd_link_hash_entry
*
519 bfd_wrapped_link_hash_lookup (bfd
*abfd
,
520 struct bfd_link_info
*info
,
528 if (info
->wrap_hash
!= NULL
)
534 if (*l
== bfd_get_symbol_leading_char (abfd
) || *l
== info
->wrap_char
)
541 #define WRAP "__wrap_"
543 if (bfd_hash_lookup (info
->wrap_hash
, l
, FALSE
, FALSE
) != NULL
)
546 struct bfd_link_hash_entry
*h
;
548 /* This symbol is being wrapped. We want to replace all
549 references to SYM with references to __wrap_SYM. */
551 amt
= strlen (l
) + sizeof WRAP
+ 1;
552 n
= bfd_malloc (amt
);
560 h
= bfd_link_hash_lookup (info
->hash
, n
, create
, TRUE
, follow
);
568 #define REAL "__real_"
571 && CONST_STRNEQ (l
, REAL
)
572 && bfd_hash_lookup (info
->wrap_hash
, l
+ sizeof REAL
- 1,
573 FALSE
, FALSE
) != NULL
)
576 struct bfd_link_hash_entry
*h
;
578 /* This is a reference to __real_SYM, where SYM is being
579 wrapped. We want to replace all references to __real_SYM
580 with references to SYM. */
582 amt
= strlen (l
+ sizeof REAL
- 1) + 2;
583 n
= bfd_malloc (amt
);
589 strcat (n
, l
+ sizeof REAL
- 1);
590 h
= bfd_link_hash_lookup (info
->hash
, n
, create
, TRUE
, follow
);
598 return bfd_link_hash_lookup (info
->hash
, string
, create
, copy
, follow
);
601 /* Traverse a generic link hash table. The only reason this is not a
602 macro is to do better type checking. This code presumes that an
603 argument passed as a struct bfd_hash_entry * may be caught as a
604 struct bfd_link_hash_entry * with no explicit cast required on the
608 bfd_link_hash_traverse
609 (struct bfd_link_hash_table
*table
,
610 bfd_boolean (*func
) (struct bfd_link_hash_entry
*, void *),
613 bfd_hash_traverse (&table
->table
,
614 (bfd_boolean (*) (struct bfd_hash_entry
*, void *)) func
,
618 /* Add a symbol to the linker hash table undefs list. */
621 bfd_link_add_undef (struct bfd_link_hash_table
*table
,
622 struct bfd_link_hash_entry
*h
)
624 BFD_ASSERT (h
->u
.undef
.next
== NULL
);
625 if (table
->undefs_tail
!= NULL
)
626 table
->undefs_tail
->u
.undef
.next
= h
;
627 if (table
->undefs
== NULL
)
629 table
->undefs_tail
= h
;
632 /* The undefs list was designed so that in normal use we don't need to
633 remove entries. However, if symbols on the list are changed from
634 bfd_link_hash_undefined to either bfd_link_hash_undefweak or
635 bfd_link_hash_new for some reason, then they must be removed from the
636 list. Failure to do so might result in the linker attempting to add
637 the symbol to the list again at a later stage. */
640 bfd_link_repair_undef_list (struct bfd_link_hash_table
*table
)
642 struct bfd_link_hash_entry
**pun
;
644 pun
= &table
->undefs
;
647 struct bfd_link_hash_entry
*h
= *pun
;
649 if (h
->type
== bfd_link_hash_new
650 || h
->type
== bfd_link_hash_undefweak
)
652 *pun
= h
->u
.undef
.next
;
653 h
->u
.undef
.next
= NULL
;
654 if (h
== table
->undefs_tail
)
656 if (pun
== &table
->undefs
)
657 table
->undefs_tail
= NULL
;
659 /* pun points at an u.undef.next field. Go back to
660 the start of the link_hash_entry. */
661 table
->undefs_tail
= (struct bfd_link_hash_entry
*)
662 ((char *) pun
- ((char *) &h
->u
.undef
.next
- (char *) h
));
667 pun
= &h
->u
.undef
.next
;
671 /* Routine to create an entry in a generic link hash table. */
673 struct bfd_hash_entry
*
674 _bfd_generic_link_hash_newfunc (struct bfd_hash_entry
*entry
,
675 struct bfd_hash_table
*table
,
678 /* Allocate the structure if it has not already been allocated by a
683 bfd_hash_allocate (table
, sizeof (struct generic_link_hash_entry
));
688 /* Call the allocation method of the superclass. */
689 entry
= _bfd_link_hash_newfunc (entry
, table
, string
);
692 struct generic_link_hash_entry
*ret
;
694 /* Set local fields. */
695 ret
= (struct generic_link_hash_entry
*) entry
;
696 ret
->written
= FALSE
;
703 /* Create a generic link hash table. */
705 struct bfd_link_hash_table
*
706 _bfd_generic_link_hash_table_create (bfd
*abfd
)
708 struct generic_link_hash_table
*ret
;
709 bfd_size_type amt
= sizeof (struct generic_link_hash_table
);
711 ret
= bfd_malloc (amt
);
714 if (! _bfd_link_hash_table_init (&ret
->root
, abfd
,
715 _bfd_generic_link_hash_newfunc
,
716 sizeof (struct generic_link_hash_entry
)))
725 _bfd_generic_link_hash_table_free (struct bfd_link_hash_table
*hash
)
727 struct generic_link_hash_table
*ret
728 = (struct generic_link_hash_table
*) hash
;
730 bfd_hash_table_free (&ret
->root
.table
);
734 /* Grab the symbols for an object file when doing a generic link. We
735 store the symbols in the outsymbols field. We need to keep them
736 around for the entire link to ensure that we only read them once.
737 If we read them multiple times, we might wind up with relocs and
738 the hash table pointing to different instances of the symbol
742 generic_link_read_symbols (bfd
*abfd
)
744 if (bfd_get_outsymbols (abfd
) == NULL
)
749 symsize
= bfd_get_symtab_upper_bound (abfd
);
752 bfd_get_outsymbols (abfd
) = bfd_alloc (abfd
, symsize
);
753 if (bfd_get_outsymbols (abfd
) == NULL
&& symsize
!= 0)
755 symcount
= bfd_canonicalize_symtab (abfd
, bfd_get_outsymbols (abfd
));
758 bfd_get_symcount (abfd
) = symcount
;
764 /* Generic function to add symbols to from an object file to the
765 global hash table. This version does not automatically collect
766 constructors by name. */
769 _bfd_generic_link_add_symbols (bfd
*abfd
, struct bfd_link_info
*info
)
771 return generic_link_add_symbols (abfd
, info
, FALSE
);
774 /* Generic function to add symbols from an object file to the global
775 hash table. This version automatically collects constructors by
776 name, as the collect2 program does. It should be used for any
777 target which does not provide some other mechanism for setting up
778 constructors and destructors; these are approximately those targets
779 for which gcc uses collect2 and do not support stabs. */
782 _bfd_generic_link_add_symbols_collect (bfd
*abfd
, struct bfd_link_info
*info
)
784 return generic_link_add_symbols (abfd
, info
, TRUE
);
787 /* Indicate that we are only retrieving symbol values from this
788 section. We want the symbols to act as though the values in the
789 file are absolute. */
792 _bfd_generic_link_just_syms (asection
*sec
,
793 struct bfd_link_info
*info ATTRIBUTE_UNUSED
)
795 sec
->output_section
= bfd_abs_section_ptr
;
796 sec
->output_offset
= sec
->vma
;
799 /* Add symbols from an object file to the global hash table. */
802 generic_link_add_symbols (bfd
*abfd
,
803 struct bfd_link_info
*info
,
808 switch (bfd_get_format (abfd
))
811 ret
= generic_link_add_object_symbols (abfd
, info
, collect
);
814 ret
= (_bfd_generic_link_add_archive_symbols
817 ? generic_link_check_archive_element_collect
818 : generic_link_check_archive_element_no_collect
)));
821 bfd_set_error (bfd_error_wrong_format
);
828 /* Add symbols from an object file to the global hash table. */
831 generic_link_add_object_symbols (bfd
*abfd
,
832 struct bfd_link_info
*info
,
835 bfd_size_type symcount
;
836 struct bfd_symbol
**outsyms
;
838 if (! generic_link_read_symbols (abfd
))
840 symcount
= _bfd_generic_link_get_symcount (abfd
);
841 outsyms
= _bfd_generic_link_get_symbols (abfd
);
842 return generic_link_add_symbol_list (abfd
, info
, symcount
, outsyms
, collect
);
845 /* We build a hash table of all symbols defined in an archive. */
847 /* An archive symbol may be defined by multiple archive elements.
848 This linked list is used to hold the elements. */
852 struct archive_list
*next
;
856 /* An entry in an archive hash table. */
858 struct archive_hash_entry
860 struct bfd_hash_entry root
;
861 /* Where the symbol is defined. */
862 struct archive_list
*defs
;
865 /* An archive hash table itself. */
867 struct archive_hash_table
869 struct bfd_hash_table table
;
872 /* Create a new entry for an archive hash table. */
874 static struct bfd_hash_entry
*
875 archive_hash_newfunc (struct bfd_hash_entry
*entry
,
876 struct bfd_hash_table
*table
,
879 struct archive_hash_entry
*ret
= (struct archive_hash_entry
*) entry
;
881 /* Allocate the structure if it has not already been allocated by a
884 ret
= bfd_hash_allocate (table
, sizeof (struct archive_hash_entry
));
888 /* Call the allocation method of the superclass. */
889 ret
= ((struct archive_hash_entry
*)
890 bfd_hash_newfunc ((struct bfd_hash_entry
*) ret
, table
, string
));
894 /* Initialize the local fields. */
901 /* Initialize an archive hash table. */
904 archive_hash_table_init
905 (struct archive_hash_table
*table
,
906 struct bfd_hash_entry
*(*newfunc
) (struct bfd_hash_entry
*,
907 struct bfd_hash_table
*,
909 unsigned int entsize
)
911 return bfd_hash_table_init (&table
->table
, newfunc
, entsize
);
914 /* Look up an entry in an archive hash table. */
916 #define archive_hash_lookup(t, string, create, copy) \
917 ((struct archive_hash_entry *) \
918 bfd_hash_lookup (&(t)->table, (string), (create), (copy)))
920 /* Allocate space in an archive hash table. */
922 #define archive_hash_allocate(t, size) bfd_hash_allocate (&(t)->table, (size))
924 /* Free an archive hash table. */
926 #define archive_hash_table_free(t) bfd_hash_table_free (&(t)->table)
928 /* Generic function to add symbols from an archive file to the global
929 hash file. This function presumes that the archive symbol table
930 has already been read in (this is normally done by the
931 bfd_check_format entry point). It looks through the undefined and
932 common symbols and searches the archive symbol table for them. If
933 it finds an entry, it includes the associated object file in the
936 The old linker looked through the archive symbol table for
937 undefined symbols. We do it the other way around, looking through
938 undefined symbols for symbols defined in the archive. The
939 advantage of the newer scheme is that we only have to look through
940 the list of undefined symbols once, whereas the old method had to
941 re-search the symbol table each time a new object file was added.
943 The CHECKFN argument is used to see if an object file should be
944 included. CHECKFN should set *PNEEDED to TRUE if the object file
945 should be included, and must also call the bfd_link_info
946 add_archive_element callback function and handle adding the symbols
947 to the global hash table. CHECKFN should only return FALSE if some
948 sort of error occurs.
950 For some formats, such as a.out, it is possible to look through an
951 object file but not actually include it in the link. The
952 archive_pass field in a BFD is used to avoid checking the symbols
953 of an object files too many times. When an object is included in
954 the link, archive_pass is set to -1. If an object is scanned but
955 not included, archive_pass is set to the pass number. The pass
956 number is incremented each time a new object file is included. The
957 pass number is used because when a new object file is included it
958 may create new undefined symbols which cause a previously examined
959 object file to be included. */
962 _bfd_generic_link_add_archive_symbols
964 struct bfd_link_info
*info
,
965 bfd_boolean (*checkfn
) (bfd
*, struct bfd_link_info
*, bfd_boolean
*))
969 register carsym
*arsym
;
971 struct archive_hash_table arsym_hash
;
973 struct bfd_link_hash_entry
**pundef
;
975 if (! bfd_has_map (abfd
))
977 /* An empty archive is a special case. */
978 if (bfd_openr_next_archived_file (abfd
, NULL
) == NULL
)
980 bfd_set_error (bfd_error_no_armap
);
984 arsyms
= bfd_ardata (abfd
)->symdefs
;
985 arsym_end
= arsyms
+ bfd_ardata (abfd
)->symdef_count
;
987 /* In order to quickly determine whether an symbol is defined in
988 this archive, we build a hash table of the symbols. */
989 if (! archive_hash_table_init (&arsym_hash
, archive_hash_newfunc
,
990 sizeof (struct archive_hash_entry
)))
992 for (arsym
= arsyms
, indx
= 0; arsym
< arsym_end
; arsym
++, indx
++)
994 struct archive_hash_entry
*arh
;
995 struct archive_list
*l
, **pp
;
997 arh
= archive_hash_lookup (&arsym_hash
, arsym
->name
, TRUE
, FALSE
);
1000 l
= ((struct archive_list
*)
1001 archive_hash_allocate (&arsym_hash
, sizeof (struct archive_list
)));
1005 for (pp
= &arh
->defs
; *pp
!= NULL
; pp
= &(*pp
)->next
)
1011 /* The archive_pass field in the archive itself is used to
1012 initialize PASS, sine we may search the same archive multiple
1014 pass
= abfd
->archive_pass
+ 1;
1016 /* New undefined symbols are added to the end of the list, so we
1017 only need to look through it once. */
1018 pundef
= &info
->hash
->undefs
;
1019 while (*pundef
!= NULL
)
1021 struct bfd_link_hash_entry
*h
;
1022 struct archive_hash_entry
*arh
;
1023 struct archive_list
*l
;
1027 /* When a symbol is defined, it is not necessarily removed from
1029 if (h
->type
!= bfd_link_hash_undefined
1030 && h
->type
!= bfd_link_hash_common
)
1032 /* Remove this entry from the list, for general cleanliness
1033 and because we are going to look through the list again
1034 if we search any more libraries. We can't remove the
1035 entry if it is the tail, because that would lose any
1036 entries we add to the list later on (it would also cause
1037 us to lose track of whether the symbol has been
1039 if (*pundef
!= info
->hash
->undefs_tail
)
1040 *pundef
= (*pundef
)->u
.undef
.next
;
1042 pundef
= &(*pundef
)->u
.undef
.next
;
1046 /* Look for this symbol in the archive symbol map. */
1047 arh
= archive_hash_lookup (&arsym_hash
, h
->root
.string
, FALSE
, FALSE
);
1050 /* If we haven't found the exact symbol we're looking for,
1051 let's look for its import thunk */
1052 if (info
->pei386_auto_import
)
1054 bfd_size_type amt
= strlen (h
->root
.string
) + 10;
1055 char *buf
= bfd_malloc (amt
);
1059 sprintf (buf
, "__imp_%s", h
->root
.string
);
1060 arh
= archive_hash_lookup (&arsym_hash
, buf
, FALSE
, FALSE
);
1065 pundef
= &(*pundef
)->u
.undef
.next
;
1069 /* Look at all the objects which define this symbol. */
1070 for (l
= arh
->defs
; l
!= NULL
; l
= l
->next
)
1075 /* If the symbol has gotten defined along the way, quit. */
1076 if (h
->type
!= bfd_link_hash_undefined
1077 && h
->type
!= bfd_link_hash_common
)
1080 element
= bfd_get_elt_at_index (abfd
, l
->indx
);
1081 if (element
== NULL
)
1084 /* If we've already included this element, or if we've
1085 already checked it on this pass, continue. */
1086 if (element
->archive_pass
== -1
1087 || element
->archive_pass
== pass
)
1090 /* If we can't figure this element out, just ignore it. */
1091 if (! bfd_check_format (element
, bfd_object
))
1093 element
->archive_pass
= -1;
1097 /* CHECKFN will see if this element should be included, and
1098 go ahead and include it if appropriate. */
1099 if (! (*checkfn
) (element
, info
, &needed
))
1103 element
->archive_pass
= pass
;
1106 element
->archive_pass
= -1;
1108 /* Increment the pass count to show that we may need to
1109 recheck object files which were already checked. */
1114 pundef
= &(*pundef
)->u
.undef
.next
;
1117 archive_hash_table_free (&arsym_hash
);
1119 /* Save PASS in case we are called again. */
1120 abfd
->archive_pass
= pass
;
1125 archive_hash_table_free (&arsym_hash
);
1129 /* See if we should include an archive element. This version is used
1130 when we do not want to automatically collect constructors based on
1131 the symbol name, presumably because we have some other mechanism
1132 for finding them. */
1135 generic_link_check_archive_element_no_collect (
1137 struct bfd_link_info
*info
,
1138 bfd_boolean
*pneeded
)
1140 return generic_link_check_archive_element (abfd
, info
, pneeded
, FALSE
);
1143 /* See if we should include an archive element. This version is used
1144 when we want to automatically collect constructors based on the
1145 symbol name, as collect2 does. */
1148 generic_link_check_archive_element_collect (bfd
*abfd
,
1149 struct bfd_link_info
*info
,
1150 bfd_boolean
*pneeded
)
1152 return generic_link_check_archive_element (abfd
, info
, pneeded
, TRUE
);
1155 /* See if we should include an archive element. Optionally collect
1159 generic_link_check_archive_element (bfd
*abfd
,
1160 struct bfd_link_info
*info
,
1161 bfd_boolean
*pneeded
,
1162 bfd_boolean collect
)
1164 asymbol
**pp
, **ppend
;
1168 if (! generic_link_read_symbols (abfd
))
1171 pp
= _bfd_generic_link_get_symbols (abfd
);
1172 ppend
= pp
+ _bfd_generic_link_get_symcount (abfd
);
1173 for (; pp
< ppend
; pp
++)
1176 struct bfd_link_hash_entry
*h
;
1180 /* We are only interested in globally visible symbols. */
1181 if (! bfd_is_com_section (p
->section
)
1182 && (p
->flags
& (BSF_GLOBAL
| BSF_INDIRECT
| BSF_WEAK
)) == 0)
1185 /* We are only interested if we know something about this
1186 symbol, and it is undefined or common. An undefined weak
1187 symbol (type bfd_link_hash_undefweak) is not considered to be
1188 a reference when pulling files out of an archive. See the
1189 SVR4 ABI, p. 4-27. */
1190 h
= bfd_link_hash_lookup (info
->hash
, bfd_asymbol_name (p
), FALSE
,
1193 || (h
->type
!= bfd_link_hash_undefined
1194 && h
->type
!= bfd_link_hash_common
))
1197 /* P is a symbol we are looking for. */
1199 if (! bfd_is_com_section (p
->section
))
1201 bfd_size_type symcount
;
1204 /* This object file defines this symbol, so pull it in. */
1205 if (! (*info
->callbacks
->add_archive_element
) (info
, abfd
,
1206 bfd_asymbol_name (p
)))
1208 symcount
= _bfd_generic_link_get_symcount (abfd
);
1209 symbols
= _bfd_generic_link_get_symbols (abfd
);
1210 if (! generic_link_add_symbol_list (abfd
, info
, symcount
,
1217 /* P is a common symbol. */
1219 if (h
->type
== bfd_link_hash_undefined
)
1225 symbfd
= h
->u
.undef
.abfd
;
1228 /* This symbol was created as undefined from outside
1229 BFD. We assume that we should link in the object
1230 file. This is for the -u option in the linker. */
1231 if (! (*info
->callbacks
->add_archive_element
)
1232 (info
, abfd
, bfd_asymbol_name (p
)))
1238 /* Turn the symbol into a common symbol but do not link in
1239 the object file. This is how a.out works. Object
1240 formats that require different semantics must implement
1241 this function differently. This symbol is already on the
1242 undefs list. We add the section to a common section
1243 attached to symbfd to ensure that it is in a BFD which
1244 will be linked in. */
1245 h
->type
= bfd_link_hash_common
;
1247 bfd_hash_allocate (&info
->hash
->table
,
1248 sizeof (struct bfd_link_hash_common_entry
));
1249 if (h
->u
.c
.p
== NULL
)
1252 size
= bfd_asymbol_value (p
);
1255 power
= bfd_log2 (size
);
1258 h
->u
.c
.p
->alignment_power
= power
;
1260 if (p
->section
== bfd_com_section_ptr
)
1261 h
->u
.c
.p
->section
= bfd_make_section_old_way (symbfd
, "COMMON");
1263 h
->u
.c
.p
->section
= bfd_make_section_old_way (symbfd
,
1265 h
->u
.c
.p
->section
->flags
= SEC_ALLOC
;
1269 /* Adjust the size of the common symbol if necessary. This
1270 is how a.out works. Object formats that require
1271 different semantics must implement this function
1273 if (bfd_asymbol_value (p
) > h
->u
.c
.size
)
1274 h
->u
.c
.size
= bfd_asymbol_value (p
);
1278 /* This archive element is not needed. */
1282 /* Add the symbols from an object file to the global hash table. ABFD
1283 is the object file. INFO is the linker information. SYMBOL_COUNT
1284 is the number of symbols. SYMBOLS is the list of symbols. COLLECT
1285 is TRUE if constructors should be automatically collected by name
1286 as is done by collect2. */
1289 generic_link_add_symbol_list (bfd
*abfd
,
1290 struct bfd_link_info
*info
,
1291 bfd_size_type symbol_count
,
1293 bfd_boolean collect
)
1295 asymbol
**pp
, **ppend
;
1298 ppend
= symbols
+ symbol_count
;
1299 for (; pp
< ppend
; pp
++)
1305 if ((p
->flags
& (BSF_INDIRECT
1310 || bfd_is_und_section (bfd_get_section (p
))
1311 || bfd_is_com_section (bfd_get_section (p
))
1312 || bfd_is_ind_section (bfd_get_section (p
)))
1316 struct generic_link_hash_entry
*h
;
1317 struct bfd_link_hash_entry
*bh
;
1319 name
= bfd_asymbol_name (p
);
1320 if (((p
->flags
& BSF_INDIRECT
) != 0
1321 || bfd_is_ind_section (p
->section
))
1325 string
= bfd_asymbol_name (*pp
);
1327 else if ((p
->flags
& BSF_WARNING
) != 0
1330 /* The name of P is actually the warning string, and the
1331 next symbol is the one to warn about. */
1334 name
= bfd_asymbol_name (*pp
);
1340 if (! (_bfd_generic_link_add_one_symbol
1341 (info
, abfd
, name
, p
->flags
, bfd_get_section (p
),
1342 p
->value
, string
, FALSE
, collect
, &bh
)))
1344 h
= (struct generic_link_hash_entry
*) bh
;
1346 /* If this is a constructor symbol, and the linker didn't do
1347 anything with it, then we want to just pass the symbol
1348 through to the output file. This will happen when
1350 if ((p
->flags
& BSF_CONSTRUCTOR
) != 0
1351 && (h
== NULL
|| h
->root
.type
== bfd_link_hash_new
))
1357 /* Save the BFD symbol so that we don't lose any backend
1358 specific information that may be attached to it. We only
1359 want this one if it gives more information than the
1360 existing one; we don't want to replace a defined symbol
1361 with an undefined one. This routine may be called with a
1362 hash table other than the generic hash table, so we only
1363 do this if we are certain that the hash table is a
1365 if (info
->hash
->creator
== abfd
->xvec
)
1368 || (! bfd_is_und_section (bfd_get_section (p
))
1369 && (! bfd_is_com_section (bfd_get_section (p
))
1370 || bfd_is_und_section (bfd_get_section (h
->sym
)))))
1373 /* BSF_OLD_COMMON is a hack to support COFF reloc
1374 reading, and it should go away when the COFF
1375 linker is switched to the new version. */
1376 if (bfd_is_com_section (bfd_get_section (p
)))
1377 p
->flags
|= BSF_OLD_COMMON
;
1381 /* Store a back pointer from the symbol to the hash
1382 table entry for the benefit of relaxation code until
1383 it gets rewritten to not use asymbol structures.
1384 Setting this is also used to check whether these
1385 symbols were set up by the generic linker. */
1393 /* We use a state table to deal with adding symbols from an object
1394 file. The first index into the state table describes the symbol
1395 from the object file. The second index into the state table is the
1396 type of the symbol in the hash table. */
1398 /* The symbol from the object file is turned into one of these row
1403 UNDEF_ROW
, /* Undefined. */
1404 UNDEFW_ROW
, /* Weak undefined. */
1405 DEF_ROW
, /* Defined. */
1406 DEFW_ROW
, /* Weak defined. */
1407 COMMON_ROW
, /* Common. */
1408 INDR_ROW
, /* Indirect. */
1409 WARN_ROW
, /* Warning. */
1410 SET_ROW
/* Member of set. */
1413 /* apparently needed for Hitachi 3050R(HI-UX/WE2)? */
1416 /* The actions to take in the state table. */
1421 UND
, /* Mark symbol undefined. */
1422 WEAK
, /* Mark symbol weak undefined. */
1423 DEF
, /* Mark symbol defined. */
1424 DEFW
, /* Mark symbol weak defined. */
1425 COM
, /* Mark symbol common. */
1426 REF
, /* Mark defined symbol referenced. */
1427 CREF
, /* Possibly warn about common reference to defined symbol. */
1428 CDEF
, /* Define existing common symbol. */
1429 NOACT
, /* No action. */
1430 BIG
, /* Mark symbol common using largest size. */
1431 MDEF
, /* Multiple definition error. */
1432 MIND
, /* Multiple indirect symbols. */
1433 IND
, /* Make indirect symbol. */
1434 CIND
, /* Make indirect symbol from existing common symbol. */
1435 SET
, /* Add value to set. */
1436 MWARN
, /* Make warning symbol. */
1437 WARN
, /* Issue warning. */
1438 CWARN
, /* Warn if referenced, else MWARN. */
1439 CYCLE
, /* Repeat with symbol pointed to. */
1440 REFC
, /* Mark indirect symbol referenced and then CYCLE. */
1441 WARNC
/* Issue warning and then CYCLE. */
1444 /* The state table itself. The first index is a link_row and the
1445 second index is a bfd_link_hash_type. */
1447 static const enum link_action link_action
[8][8] =
1449 /* current\prev new undef undefw def defw com indr warn */
1450 /* UNDEF_ROW */ {UND
, NOACT
, UND
, REF
, REF
, NOACT
, REFC
, WARNC
},
1451 /* UNDEFW_ROW */ {WEAK
, NOACT
, NOACT
, REF
, REF
, NOACT
, REFC
, WARNC
},
1452 /* DEF_ROW */ {DEF
, DEF
, DEF
, MDEF
, DEF
, CDEF
, MDEF
, CYCLE
},
1453 /* DEFW_ROW */ {DEFW
, DEFW
, DEFW
, NOACT
, NOACT
, NOACT
, NOACT
, CYCLE
},
1454 /* COMMON_ROW */ {COM
, COM
, COM
, CREF
, COM
, BIG
, REFC
, WARNC
},
1455 /* INDR_ROW */ {IND
, IND
, IND
, MDEF
, IND
, CIND
, MIND
, CYCLE
},
1456 /* WARN_ROW */ {MWARN
, WARN
, WARN
, CWARN
, CWARN
, WARN
, CWARN
, NOACT
},
1457 /* SET_ROW */ {SET
, SET
, SET
, SET
, SET
, SET
, CYCLE
, CYCLE
}
1460 /* Most of the entries in the LINK_ACTION table are straightforward,
1461 but a few are somewhat subtle.
1463 A reference to an indirect symbol (UNDEF_ROW/indr or
1464 UNDEFW_ROW/indr) is counted as a reference both to the indirect
1465 symbol and to the symbol the indirect symbol points to.
1467 A reference to a warning symbol (UNDEF_ROW/warn or UNDEFW_ROW/warn)
1468 causes the warning to be issued.
1470 A common definition of an indirect symbol (COMMON_ROW/indr) is
1471 treated as a multiple definition error. Likewise for an indirect
1472 definition of a common symbol (INDR_ROW/com).
1474 An indirect definition of a warning (INDR_ROW/warn) does not cause
1475 the warning to be issued.
1477 If a warning is created for an indirect symbol (WARN_ROW/indr) no
1478 warning is created for the symbol the indirect symbol points to.
1480 Adding an entry to a set does not count as a reference to a set,
1481 and no warning is issued (SET_ROW/warn). */
1483 /* Return the BFD in which a hash entry has been defined, if known. */
1486 hash_entry_bfd (struct bfd_link_hash_entry
*h
)
1488 while (h
->type
== bfd_link_hash_warning
)
1494 case bfd_link_hash_undefined
:
1495 case bfd_link_hash_undefweak
:
1496 return h
->u
.undef
.abfd
;
1497 case bfd_link_hash_defined
:
1498 case bfd_link_hash_defweak
:
1499 return h
->u
.def
.section
->owner
;
1500 case bfd_link_hash_common
:
1501 return h
->u
.c
.p
->section
->owner
;
1506 /* Add a symbol to the global hash table.
1507 ABFD is the BFD the symbol comes from.
1508 NAME is the name of the symbol.
1509 FLAGS is the BSF_* bits associated with the symbol.
1510 SECTION is the section in which the symbol is defined; this may be
1511 bfd_und_section_ptr or bfd_com_section_ptr.
1512 VALUE is the value of the symbol, relative to the section.
1513 STRING is used for either an indirect symbol, in which case it is
1514 the name of the symbol to indirect to, or a warning symbol, in
1515 which case it is the warning string.
1516 COPY is TRUE if NAME or STRING must be copied into locally
1517 allocated memory if they need to be saved.
1518 COLLECT is TRUE if we should automatically collect gcc constructor
1519 or destructor names as collect2 does.
1520 HASHP, if not NULL, is a place to store the created hash table
1521 entry; if *HASHP is not NULL, the caller has already looked up
1522 the hash table entry, and stored it in *HASHP. */
1525 _bfd_generic_link_add_one_symbol (struct bfd_link_info
*info
,
1533 bfd_boolean collect
,
1534 struct bfd_link_hash_entry
**hashp
)
1537 struct bfd_link_hash_entry
*h
;
1540 if (bfd_is_ind_section (section
)
1541 || (flags
& BSF_INDIRECT
) != 0)
1543 else if ((flags
& BSF_WARNING
) != 0)
1545 else if ((flags
& BSF_CONSTRUCTOR
) != 0)
1547 else if (bfd_is_und_section (section
))
1549 if ((flags
& BSF_WEAK
) != 0)
1554 else if ((flags
& BSF_WEAK
) != 0)
1556 else if (bfd_is_com_section (section
))
1561 if (hashp
!= NULL
&& *hashp
!= NULL
)
1565 if (row
== UNDEF_ROW
|| row
== UNDEFW_ROW
)
1566 h
= bfd_wrapped_link_hash_lookup (abfd
, info
, name
, TRUE
, copy
, FALSE
);
1568 h
= bfd_link_hash_lookup (info
->hash
, name
, TRUE
, copy
, FALSE
);
1577 if (info
->notice_all
1578 || (info
->notice_hash
!= NULL
1579 && bfd_hash_lookup (info
->notice_hash
, name
, FALSE
, FALSE
) != NULL
))
1581 if (! (*info
->callbacks
->notice
) (info
, h
->root
.string
, abfd
, section
,
1591 enum link_action action
;
1594 action
= link_action
[(int) row
][(int) h
->type
];
1605 /* Make a new undefined symbol. */
1606 h
->type
= bfd_link_hash_undefined
;
1607 h
->u
.undef
.abfd
= abfd
;
1608 bfd_link_add_undef (info
->hash
, h
);
1612 /* Make a new weak undefined symbol. */
1613 h
->type
= bfd_link_hash_undefweak
;
1614 h
->u
.undef
.abfd
= abfd
;
1615 h
->u
.undef
.weak
= abfd
;
1619 /* We have found a definition for a symbol which was
1620 previously common. */
1621 BFD_ASSERT (h
->type
== bfd_link_hash_common
);
1622 if (! ((*info
->callbacks
->multiple_common
)
1623 (info
, h
->root
.string
,
1624 h
->u
.c
.p
->section
->owner
, bfd_link_hash_common
, h
->u
.c
.size
,
1625 abfd
, bfd_link_hash_defined
, 0)))
1631 enum bfd_link_hash_type oldtype
;
1633 /* Define a symbol. */
1636 h
->type
= bfd_link_hash_defweak
;
1638 h
->type
= bfd_link_hash_defined
;
1639 h
->u
.def
.section
= section
;
1640 h
->u
.def
.value
= value
;
1642 /* If we have been asked to, we act like collect2 and
1643 identify all functions that might be global
1644 constructors and destructors and pass them up in a
1645 callback. We only do this for certain object file
1646 types, since many object file types can handle this
1648 if (collect
&& name
[0] == '_')
1652 /* A constructor or destructor name starts like this:
1653 _+GLOBAL_[_.$][ID][_.$] where the first [_.$] and
1654 the second are the same character (we accept any
1655 character there, in case a new object file format
1656 comes along with even worse naming restrictions). */
1658 #define CONS_PREFIX "GLOBAL_"
1659 #define CONS_PREFIX_LEN (sizeof CONS_PREFIX - 1)
1664 if (s
[0] == 'G' && CONST_STRNEQ (s
, CONS_PREFIX
))
1668 c
= s
[CONS_PREFIX_LEN
+ 1];
1669 if ((c
== 'I' || c
== 'D')
1670 && s
[CONS_PREFIX_LEN
] == s
[CONS_PREFIX_LEN
+ 2])
1672 /* If this is a definition of a symbol which
1673 was previously weakly defined, we are in
1674 trouble. We have already added a
1675 constructor entry for the weak defined
1676 symbol, and now we are trying to add one
1677 for the new symbol. Fortunately, this case
1678 should never arise in practice. */
1679 if (oldtype
== bfd_link_hash_defweak
)
1682 if (! ((*info
->callbacks
->constructor
)
1684 h
->root
.string
, abfd
, section
, value
)))
1694 /* We have found a common definition for a symbol. */
1695 if (h
->type
== bfd_link_hash_new
)
1696 bfd_link_add_undef (info
->hash
, h
);
1697 h
->type
= bfd_link_hash_common
;
1699 bfd_hash_allocate (&info
->hash
->table
,
1700 sizeof (struct bfd_link_hash_common_entry
));
1701 if (h
->u
.c
.p
== NULL
)
1704 h
->u
.c
.size
= value
;
1706 /* Select a default alignment based on the size. This may
1707 be overridden by the caller. */
1711 power
= bfd_log2 (value
);
1714 h
->u
.c
.p
->alignment_power
= power
;
1717 /* The section of a common symbol is only used if the common
1718 symbol is actually allocated. It basically provides a
1719 hook for the linker script to decide which output section
1720 the common symbols should be put in. In most cases, the
1721 section of a common symbol will be bfd_com_section_ptr,
1722 the code here will choose a common symbol section named
1723 "COMMON", and the linker script will contain *(COMMON) in
1724 the appropriate place. A few targets use separate common
1725 sections for small symbols, and they require special
1727 if (section
== bfd_com_section_ptr
)
1729 h
->u
.c
.p
->section
= bfd_make_section_old_way (abfd
, "COMMON");
1730 h
->u
.c
.p
->section
->flags
= SEC_ALLOC
;
1732 else if (section
->owner
!= abfd
)
1734 h
->u
.c
.p
->section
= bfd_make_section_old_way (abfd
,
1736 h
->u
.c
.p
->section
->flags
= SEC_ALLOC
;
1739 h
->u
.c
.p
->section
= section
;
1743 /* A reference to a defined symbol. */
1744 if (h
->u
.undef
.next
== NULL
&& info
->hash
->undefs_tail
!= h
)
1745 h
->u
.undef
.next
= h
;
1749 /* We have found a common definition for a symbol which
1750 already had a common definition. Use the maximum of the
1751 two sizes, and use the section required by the larger symbol. */
1752 BFD_ASSERT (h
->type
== bfd_link_hash_common
);
1753 if (! ((*info
->callbacks
->multiple_common
)
1754 (info
, h
->root
.string
,
1755 h
->u
.c
.p
->section
->owner
, bfd_link_hash_common
, h
->u
.c
.size
,
1756 abfd
, bfd_link_hash_common
, value
)))
1758 if (value
> h
->u
.c
.size
)
1762 h
->u
.c
.size
= value
;
1764 /* Select a default alignment based on the size. This may
1765 be overridden by the caller. */
1766 power
= bfd_log2 (value
);
1769 h
->u
.c
.p
->alignment_power
= power
;
1771 /* Some systems have special treatment for small commons,
1772 hence we want to select the section used by the larger
1773 symbol. This makes sure the symbol does not go in a
1774 small common section if it is now too large. */
1775 if (section
== bfd_com_section_ptr
)
1778 = bfd_make_section_old_way (abfd
, "COMMON");
1779 h
->u
.c
.p
->section
->flags
= SEC_ALLOC
;
1781 else if (section
->owner
!= abfd
)
1784 = bfd_make_section_old_way (abfd
, section
->name
);
1785 h
->u
.c
.p
->section
->flags
= SEC_ALLOC
;
1788 h
->u
.c
.p
->section
= section
;
1796 /* We have found a common definition for a symbol which
1797 was already defined. FIXME: It would nice if we could
1798 report the BFD which defined an indirect symbol, but we
1799 don't have anywhere to store the information. */
1800 if (h
->type
== bfd_link_hash_defined
1801 || h
->type
== bfd_link_hash_defweak
)
1802 obfd
= h
->u
.def
.section
->owner
;
1805 if (! ((*info
->callbacks
->multiple_common
)
1806 (info
, h
->root
.string
, obfd
, h
->type
, 0,
1807 abfd
, bfd_link_hash_common
, value
)))
1813 /* Multiple indirect symbols. This is OK if they both point
1814 to the same symbol. */
1815 if (strcmp (h
->u
.i
.link
->root
.string
, string
) == 0)
1819 /* Handle a multiple definition. */
1820 if (!info
->allow_multiple_definition
)
1822 asection
*msec
= NULL
;
1827 case bfd_link_hash_defined
:
1828 msec
= h
->u
.def
.section
;
1829 mval
= h
->u
.def
.value
;
1831 case bfd_link_hash_indirect
:
1832 msec
= bfd_ind_section_ptr
;
1839 /* Ignore a redefinition of an absolute symbol to the
1840 same value; it's harmless. */
1841 if (h
->type
== bfd_link_hash_defined
1842 && bfd_is_abs_section (msec
)
1843 && bfd_is_abs_section (section
)
1847 if (! ((*info
->callbacks
->multiple_definition
)
1848 (info
, h
->root
.string
, msec
->owner
, msec
, mval
,
1849 abfd
, section
, value
)))
1855 /* Create an indirect symbol from an existing common symbol. */
1856 BFD_ASSERT (h
->type
== bfd_link_hash_common
);
1857 if (! ((*info
->callbacks
->multiple_common
)
1858 (info
, h
->root
.string
,
1859 h
->u
.c
.p
->section
->owner
, bfd_link_hash_common
, h
->u
.c
.size
,
1860 abfd
, bfd_link_hash_indirect
, 0)))
1864 /* Create an indirect symbol. */
1866 struct bfd_link_hash_entry
*inh
;
1868 /* STRING is the name of the symbol we want to indirect
1870 inh
= bfd_wrapped_link_hash_lookup (abfd
, info
, string
, TRUE
,
1874 if (inh
->type
== bfd_link_hash_indirect
1875 && inh
->u
.i
.link
== h
)
1877 (*_bfd_error_handler
)
1878 (_("%B: indirect symbol `%s' to `%s' is a loop"),
1879 abfd
, name
, string
);
1880 bfd_set_error (bfd_error_invalid_operation
);
1883 if (inh
->type
== bfd_link_hash_new
)
1885 inh
->type
= bfd_link_hash_undefined
;
1886 inh
->u
.undef
.abfd
= abfd
;
1887 bfd_link_add_undef (info
->hash
, inh
);
1890 /* If the indirect symbol has been referenced, we need to
1891 push the reference down to the symbol we are
1893 if (h
->type
!= bfd_link_hash_new
)
1899 h
->type
= bfd_link_hash_indirect
;
1905 /* Add an entry to a set. */
1906 if (! (*info
->callbacks
->add_to_set
) (info
, h
, BFD_RELOC_CTOR
,
1907 abfd
, section
, value
))
1912 /* Issue a warning and cycle. */
1913 if (h
->u
.i
.warning
!= NULL
)
1915 if (! (*info
->callbacks
->warning
) (info
, h
->u
.i
.warning
,
1916 h
->root
.string
, abfd
,
1919 /* Only issue a warning once. */
1920 h
->u
.i
.warning
= NULL
;
1924 /* Try again with the referenced symbol. */
1930 /* A reference to an indirect symbol. */
1931 if (h
->u
.undef
.next
== NULL
&& info
->hash
->undefs_tail
!= h
)
1932 h
->u
.undef
.next
= h
;
1938 /* Issue a warning. */
1939 if (! (*info
->callbacks
->warning
) (info
, string
, h
->root
.string
,
1940 hash_entry_bfd (h
), NULL
, 0))
1945 /* Warn if this symbol has been referenced already,
1946 otherwise add a warning. A symbol has been referenced if
1947 the u.undef.next field is not NULL, or it is the tail of the
1948 undefined symbol list. The REF case above helps to
1950 if (h
->u
.undef
.next
!= NULL
|| info
->hash
->undefs_tail
== h
)
1952 if (! (*info
->callbacks
->warning
) (info
, string
, h
->root
.string
,
1953 hash_entry_bfd (h
), NULL
, 0))
1959 /* Make a warning symbol. */
1961 struct bfd_link_hash_entry
*sub
;
1963 /* STRING is the warning to give. */
1964 sub
= ((struct bfd_link_hash_entry
*)
1965 ((*info
->hash
->table
.newfunc
)
1966 (NULL
, &info
->hash
->table
, h
->root
.string
)));
1970 sub
->type
= bfd_link_hash_warning
;
1973 sub
->u
.i
.warning
= string
;
1977 size_t len
= strlen (string
) + 1;
1979 w
= bfd_hash_allocate (&info
->hash
->table
, len
);
1982 memcpy (w
, string
, len
);
1983 sub
->u
.i
.warning
= w
;
1986 bfd_hash_replace (&info
->hash
->table
,
1987 (struct bfd_hash_entry
*) h
,
1988 (struct bfd_hash_entry
*) sub
);
2000 /* Generic final link routine. */
2003 _bfd_generic_final_link (bfd
*abfd
, struct bfd_link_info
*info
)
2007 struct bfd_link_order
*p
;
2009 struct generic_write_global_symbol_info wginfo
;
2011 bfd_get_outsymbols (abfd
) = NULL
;
2012 bfd_get_symcount (abfd
) = 0;
2015 /* Mark all sections which will be included in the output file. */
2016 for (o
= abfd
->sections
; o
!= NULL
; o
= o
->next
)
2017 for (p
= o
->map_head
.link_order
; p
!= NULL
; p
= p
->next
)
2018 if (p
->type
== bfd_indirect_link_order
)
2019 p
->u
.indirect
.section
->linker_mark
= TRUE
;
2021 /* Build the output symbol table. */
2022 for (sub
= info
->input_bfds
; sub
!= NULL
; sub
= sub
->link_next
)
2023 if (! _bfd_generic_link_output_symbols (abfd
, sub
, info
, &outsymalloc
))
2026 /* Accumulate the global symbols. */
2028 wginfo
.output_bfd
= abfd
;
2029 wginfo
.psymalloc
= &outsymalloc
;
2030 _bfd_generic_link_hash_traverse (_bfd_generic_hash_table (info
),
2031 _bfd_generic_link_write_global_symbol
,
2034 /* Make sure we have a trailing NULL pointer on OUTSYMBOLS. We
2035 shouldn't really need one, since we have SYMCOUNT, but some old
2036 code still expects one. */
2037 if (! generic_add_output_symbol (abfd
, &outsymalloc
, NULL
))
2040 if (info
->relocatable
)
2042 /* Allocate space for the output relocs for each section. */
2043 for (o
= abfd
->sections
; o
!= NULL
; o
= o
->next
)
2046 for (p
= o
->map_head
.link_order
; p
!= NULL
; p
= p
->next
)
2048 if (p
->type
== bfd_section_reloc_link_order
2049 || p
->type
== bfd_symbol_reloc_link_order
)
2051 else if (p
->type
== bfd_indirect_link_order
)
2053 asection
*input_section
;
2060 input_section
= p
->u
.indirect
.section
;
2061 input_bfd
= input_section
->owner
;
2062 relsize
= bfd_get_reloc_upper_bound (input_bfd
,
2066 relocs
= bfd_malloc (relsize
);
2067 if (!relocs
&& relsize
!= 0)
2069 symbols
= _bfd_generic_link_get_symbols (input_bfd
);
2070 reloc_count
= bfd_canonicalize_reloc (input_bfd
,
2075 if (reloc_count
< 0)
2077 BFD_ASSERT ((unsigned long) reloc_count
2078 == input_section
->reloc_count
);
2079 o
->reloc_count
+= reloc_count
;
2082 if (o
->reloc_count
> 0)
2086 amt
= o
->reloc_count
;
2087 amt
*= sizeof (arelent
*);
2088 o
->orelocation
= bfd_alloc (abfd
, amt
);
2089 if (!o
->orelocation
)
2091 o
->flags
|= SEC_RELOC
;
2092 /* Reset the count so that it can be used as an index
2093 when putting in the output relocs. */
2099 /* Handle all the link order information for the sections. */
2100 for (o
= abfd
->sections
; o
!= NULL
; o
= o
->next
)
2102 for (p
= o
->map_head
.link_order
; p
!= NULL
; p
= p
->next
)
2106 case bfd_section_reloc_link_order
:
2107 case bfd_symbol_reloc_link_order
:
2108 if (! _bfd_generic_reloc_link_order (abfd
, info
, o
, p
))
2111 case bfd_indirect_link_order
:
2112 if (! default_indirect_link_order (abfd
, info
, o
, p
, TRUE
))
2116 if (! _bfd_default_link_order (abfd
, info
, o
, p
))
2126 /* Add an output symbol to the output BFD. */
2129 generic_add_output_symbol (bfd
*output_bfd
, size_t *psymalloc
, asymbol
*sym
)
2131 if (bfd_get_symcount (output_bfd
) >= *psymalloc
)
2136 if (*psymalloc
== 0)
2141 amt
*= sizeof (asymbol
*);
2142 newsyms
= bfd_realloc (bfd_get_outsymbols (output_bfd
), amt
);
2143 if (newsyms
== NULL
)
2145 bfd_get_outsymbols (output_bfd
) = newsyms
;
2148 bfd_get_outsymbols (output_bfd
) [bfd_get_symcount (output_bfd
)] = sym
;
2150 ++ bfd_get_symcount (output_bfd
);
2155 /* Handle the symbols for an input BFD. */
2158 _bfd_generic_link_output_symbols (bfd
*output_bfd
,
2160 struct bfd_link_info
*info
,
2166 if (! generic_link_read_symbols (input_bfd
))
2169 /* Create a filename symbol if we are supposed to. */
2170 if (info
->create_object_symbols_section
!= NULL
)
2174 for (sec
= input_bfd
->sections
; sec
!= NULL
; sec
= sec
->next
)
2176 if (sec
->output_section
== info
->create_object_symbols_section
)
2180 newsym
= bfd_make_empty_symbol (input_bfd
);
2183 newsym
->name
= input_bfd
->filename
;
2185 newsym
->flags
= BSF_LOCAL
| BSF_FILE
;
2186 newsym
->section
= sec
;
2188 if (! generic_add_output_symbol (output_bfd
, psymalloc
,
2197 /* Adjust the values of the globally visible symbols, and write out
2199 sym_ptr
= _bfd_generic_link_get_symbols (input_bfd
);
2200 sym_end
= sym_ptr
+ _bfd_generic_link_get_symcount (input_bfd
);
2201 for (; sym_ptr
< sym_end
; sym_ptr
++)
2204 struct generic_link_hash_entry
*h
;
2209 if ((sym
->flags
& (BSF_INDIRECT
2214 || bfd_is_und_section (bfd_get_section (sym
))
2215 || bfd_is_com_section (bfd_get_section (sym
))
2216 || bfd_is_ind_section (bfd_get_section (sym
)))
2218 if (sym
->udata
.p
!= NULL
)
2220 else if ((sym
->flags
& BSF_CONSTRUCTOR
) != 0)
2222 /* This case normally means that the main linker code
2223 deliberately ignored this constructor symbol. We
2224 should just pass it through. This will screw up if
2225 the constructor symbol is from a different,
2226 non-generic, object file format, but the case will
2227 only arise when linking with -r, which will probably
2228 fail anyhow, since there will be no way to represent
2229 the relocs in the output format being used. */
2232 else if (bfd_is_und_section (bfd_get_section (sym
)))
2233 h
= ((struct generic_link_hash_entry
*)
2234 bfd_wrapped_link_hash_lookup (output_bfd
, info
,
2235 bfd_asymbol_name (sym
),
2236 FALSE
, FALSE
, TRUE
));
2238 h
= _bfd_generic_link_hash_lookup (_bfd_generic_hash_table (info
),
2239 bfd_asymbol_name (sym
),
2240 FALSE
, FALSE
, TRUE
);
2244 /* Force all references to this symbol to point to
2245 the same area in memory. It is possible that
2246 this routine will be called with a hash table
2247 other than a generic hash table, so we double
2249 if (info
->hash
->creator
== input_bfd
->xvec
)
2252 *sym_ptr
= sym
= h
->sym
;
2255 switch (h
->root
.type
)
2258 case bfd_link_hash_new
:
2260 case bfd_link_hash_undefined
:
2262 case bfd_link_hash_undefweak
:
2263 sym
->flags
|= BSF_WEAK
;
2265 case bfd_link_hash_indirect
:
2266 h
= (struct generic_link_hash_entry
*) h
->root
.u
.i
.link
;
2268 case bfd_link_hash_defined
:
2269 sym
->flags
|= BSF_GLOBAL
;
2270 sym
->flags
&=~ BSF_CONSTRUCTOR
;
2271 sym
->value
= h
->root
.u
.def
.value
;
2272 sym
->section
= h
->root
.u
.def
.section
;
2274 case bfd_link_hash_defweak
:
2275 sym
->flags
|= BSF_WEAK
;
2276 sym
->flags
&=~ BSF_CONSTRUCTOR
;
2277 sym
->value
= h
->root
.u
.def
.value
;
2278 sym
->section
= h
->root
.u
.def
.section
;
2280 case bfd_link_hash_common
:
2281 sym
->value
= h
->root
.u
.c
.size
;
2282 sym
->flags
|= BSF_GLOBAL
;
2283 if (! bfd_is_com_section (sym
->section
))
2285 BFD_ASSERT (bfd_is_und_section (sym
->section
));
2286 sym
->section
= bfd_com_section_ptr
;
2288 /* We do not set the section of the symbol to
2289 h->root.u.c.p->section. That value was saved so
2290 that we would know where to allocate the symbol
2291 if it was defined. In this case the type is
2292 still bfd_link_hash_common, so we did not define
2293 it, so we do not want to use that section. */
2299 /* This switch is straight from the old code in
2300 write_file_locals in ldsym.c. */
2301 if (info
->strip
== strip_all
2302 || (info
->strip
== strip_some
2303 && bfd_hash_lookup (info
->keep_hash
, bfd_asymbol_name (sym
),
2304 FALSE
, FALSE
) == NULL
))
2306 else if ((sym
->flags
& (BSF_GLOBAL
| BSF_WEAK
)) != 0)
2308 /* If this symbol is marked as occurring now, rather
2309 than at the end, output it now. This is used for
2310 COFF C_EXT FCN symbols. FIXME: There must be a
2312 if (bfd_asymbol_bfd (sym
) == input_bfd
2313 && (sym
->flags
& BSF_NOT_AT_END
) != 0)
2318 else if (bfd_is_ind_section (sym
->section
))
2320 else if ((sym
->flags
& BSF_DEBUGGING
) != 0)
2322 if (info
->strip
== strip_none
)
2327 else if (bfd_is_und_section (sym
->section
)
2328 || bfd_is_com_section (sym
->section
))
2330 else if ((sym
->flags
& BSF_LOCAL
) != 0)
2332 if ((sym
->flags
& BSF_WARNING
) != 0)
2336 switch (info
->discard
)
2342 case discard_sec_merge
:
2344 if (info
->relocatable
2345 || ! (sym
->section
->flags
& SEC_MERGE
))
2349 if (bfd_is_local_label (input_bfd
, sym
))
2360 else if ((sym
->flags
& BSF_CONSTRUCTOR
))
2362 if (info
->strip
!= strip_all
)
2370 /* If this symbol is in a section which is not being included
2371 in the output file, then we don't want to output the
2373 if (!bfd_is_abs_section (sym
->section
)
2374 && bfd_section_removed_from_list (output_bfd
,
2375 sym
->section
->output_section
))
2380 if (! generic_add_output_symbol (output_bfd
, psymalloc
, sym
))
2390 /* Set the section and value of a generic BFD symbol based on a linker
2391 hash table entry. */
2394 set_symbol_from_hash (asymbol
*sym
, struct bfd_link_hash_entry
*h
)
2401 case bfd_link_hash_new
:
2402 /* This can happen when a constructor symbol is seen but we are
2403 not building constructors. */
2404 if (sym
->section
!= NULL
)
2406 BFD_ASSERT ((sym
->flags
& BSF_CONSTRUCTOR
) != 0);
2410 sym
->flags
|= BSF_CONSTRUCTOR
;
2411 sym
->section
= bfd_abs_section_ptr
;
2415 case bfd_link_hash_undefined
:
2416 sym
->section
= bfd_und_section_ptr
;
2419 case bfd_link_hash_undefweak
:
2420 sym
->section
= bfd_und_section_ptr
;
2422 sym
->flags
|= BSF_WEAK
;
2424 case bfd_link_hash_defined
:
2425 sym
->section
= h
->u
.def
.section
;
2426 sym
->value
= h
->u
.def
.value
;
2428 case bfd_link_hash_defweak
:
2429 sym
->flags
|= BSF_WEAK
;
2430 sym
->section
= h
->u
.def
.section
;
2431 sym
->value
= h
->u
.def
.value
;
2433 case bfd_link_hash_common
:
2434 sym
->value
= h
->u
.c
.size
;
2435 if (sym
->section
== NULL
)
2436 sym
->section
= bfd_com_section_ptr
;
2437 else if (! bfd_is_com_section (sym
->section
))
2439 BFD_ASSERT (bfd_is_und_section (sym
->section
));
2440 sym
->section
= bfd_com_section_ptr
;
2442 /* Do not set the section; see _bfd_generic_link_output_symbols. */
2444 case bfd_link_hash_indirect
:
2445 case bfd_link_hash_warning
:
2446 /* FIXME: What should we do here? */
2451 /* Write out a global symbol, if it hasn't already been written out.
2452 This is called for each symbol in the hash table. */
2455 _bfd_generic_link_write_global_symbol (struct generic_link_hash_entry
*h
,
2458 struct generic_write_global_symbol_info
*wginfo
= data
;
2461 if (h
->root
.type
== bfd_link_hash_warning
)
2462 h
= (struct generic_link_hash_entry
*) h
->root
.u
.i
.link
;
2469 if (wginfo
->info
->strip
== strip_all
2470 || (wginfo
->info
->strip
== strip_some
2471 && bfd_hash_lookup (wginfo
->info
->keep_hash
, h
->root
.root
.string
,
2472 FALSE
, FALSE
) == NULL
))
2479 sym
= bfd_make_empty_symbol (wginfo
->output_bfd
);
2482 sym
->name
= h
->root
.root
.string
;
2486 set_symbol_from_hash (sym
, &h
->root
);
2488 sym
->flags
|= BSF_GLOBAL
;
2490 if (! generic_add_output_symbol (wginfo
->output_bfd
, wginfo
->psymalloc
,
2493 /* FIXME: No way to return failure. */
2500 /* Create a relocation. */
2503 _bfd_generic_reloc_link_order (bfd
*abfd
,
2504 struct bfd_link_info
*info
,
2506 struct bfd_link_order
*link_order
)
2510 if (! info
->relocatable
)
2512 if (sec
->orelocation
== NULL
)
2515 r
= bfd_alloc (abfd
, sizeof (arelent
));
2519 r
->address
= link_order
->offset
;
2520 r
->howto
= bfd_reloc_type_lookup (abfd
, link_order
->u
.reloc
.p
->reloc
);
2523 bfd_set_error (bfd_error_bad_value
);
2527 /* Get the symbol to use for the relocation. */
2528 if (link_order
->type
== bfd_section_reloc_link_order
)
2529 r
->sym_ptr_ptr
= link_order
->u
.reloc
.p
->u
.section
->symbol_ptr_ptr
;
2532 struct generic_link_hash_entry
*h
;
2534 h
= ((struct generic_link_hash_entry
*)
2535 bfd_wrapped_link_hash_lookup (abfd
, info
,
2536 link_order
->u
.reloc
.p
->u
.name
,
2537 FALSE
, FALSE
, TRUE
));
2541 if (! ((*info
->callbacks
->unattached_reloc
)
2542 (info
, link_order
->u
.reloc
.p
->u
.name
, NULL
, NULL
, 0)))
2544 bfd_set_error (bfd_error_bad_value
);
2547 r
->sym_ptr_ptr
= &h
->sym
;
2550 /* If this is an inplace reloc, write the addend to the object file.
2551 Otherwise, store it in the reloc addend. */
2552 if (! r
->howto
->partial_inplace
)
2553 r
->addend
= link_order
->u
.reloc
.p
->addend
;
2557 bfd_reloc_status_type rstat
;
2562 size
= bfd_get_reloc_size (r
->howto
);
2563 buf
= bfd_zmalloc (size
);
2566 rstat
= _bfd_relocate_contents (r
->howto
, abfd
,
2567 (bfd_vma
) link_order
->u
.reloc
.p
->addend
,
2574 case bfd_reloc_outofrange
:
2576 case bfd_reloc_overflow
:
2577 if (! ((*info
->callbacks
->reloc_overflow
)
2579 (link_order
->type
== bfd_section_reloc_link_order
2580 ? bfd_section_name (abfd
, link_order
->u
.reloc
.p
->u
.section
)
2581 : link_order
->u
.reloc
.p
->u
.name
),
2582 r
->howto
->name
, link_order
->u
.reloc
.p
->addend
,
2590 loc
= link_order
->offset
* bfd_octets_per_byte (abfd
);
2591 ok
= bfd_set_section_contents (abfd
, sec
, buf
, loc
, size
);
2599 sec
->orelocation
[sec
->reloc_count
] = r
;
2605 /* Allocate a new link_order for a section. */
2607 struct bfd_link_order
*
2608 bfd_new_link_order (bfd
*abfd
, asection
*section
)
2610 bfd_size_type amt
= sizeof (struct bfd_link_order
);
2611 struct bfd_link_order
*new;
2613 new = bfd_zalloc (abfd
, amt
);
2617 new->type
= bfd_undefined_link_order
;
2619 if (section
->map_tail
.link_order
!= NULL
)
2620 section
->map_tail
.link_order
->next
= new;
2622 section
->map_head
.link_order
= new;
2623 section
->map_tail
.link_order
= new;
2628 /* Default link order processing routine. Note that we can not handle
2629 the reloc_link_order types here, since they depend upon the details
2630 of how the particular backends generates relocs. */
2633 _bfd_default_link_order (bfd
*abfd
,
2634 struct bfd_link_info
*info
,
2636 struct bfd_link_order
*link_order
)
2638 switch (link_order
->type
)
2640 case bfd_undefined_link_order
:
2641 case bfd_section_reloc_link_order
:
2642 case bfd_symbol_reloc_link_order
:
2645 case bfd_indirect_link_order
:
2646 return default_indirect_link_order (abfd
, info
, sec
, link_order
,
2648 case bfd_data_link_order
:
2649 return default_data_link_order (abfd
, info
, sec
, link_order
);
2653 /* Default routine to handle a bfd_data_link_order. */
2656 default_data_link_order (bfd
*abfd
,
2657 struct bfd_link_info
*info ATTRIBUTE_UNUSED
,
2659 struct bfd_link_order
*link_order
)
2667 BFD_ASSERT ((sec
->flags
& SEC_HAS_CONTENTS
) != 0);
2669 size
= link_order
->size
;
2673 fill
= link_order
->u
.data
.contents
;
2674 fill_size
= link_order
->u
.data
.size
;
2675 if (fill_size
!= 0 && fill_size
< size
)
2678 fill
= bfd_malloc (size
);
2683 memset (p
, (int) link_order
->u
.data
.contents
[0], (size_t) size
);
2688 memcpy (p
, link_order
->u
.data
.contents
, fill_size
);
2692 while (size
>= fill_size
);
2694 memcpy (p
, link_order
->u
.data
.contents
, (size_t) size
);
2695 size
= link_order
->size
;
2699 loc
= link_order
->offset
* bfd_octets_per_byte (abfd
);
2700 result
= bfd_set_section_contents (abfd
, sec
, fill
, loc
, size
);
2702 if (fill
!= link_order
->u
.data
.contents
)
2707 /* Default routine to handle a bfd_indirect_link_order. */
2710 default_indirect_link_order (bfd
*output_bfd
,
2711 struct bfd_link_info
*info
,
2712 asection
*output_section
,
2713 struct bfd_link_order
*link_order
,
2714 bfd_boolean generic_linker
)
2716 asection
*input_section
;
2718 bfd_byte
*contents
= NULL
;
2719 bfd_byte
*new_contents
;
2720 bfd_size_type sec_size
;
2723 BFD_ASSERT ((output_section
->flags
& SEC_HAS_CONTENTS
) != 0);
2725 input_section
= link_order
->u
.indirect
.section
;
2726 input_bfd
= input_section
->owner
;
2727 if (input_section
->size
== 0)
2730 BFD_ASSERT (input_section
->output_section
== output_section
);
2731 BFD_ASSERT (input_section
->output_offset
== link_order
->offset
);
2732 BFD_ASSERT (input_section
->size
== link_order
->size
);
2734 if (info
->relocatable
2735 && input_section
->reloc_count
> 0
2736 && output_section
->orelocation
== NULL
)
2738 /* Space has not been allocated for the output relocations.
2739 This can happen when we are called by a specific backend
2740 because somebody is attempting to link together different
2741 types of object files. Handling this case correctly is
2742 difficult, and sometimes impossible. */
2743 (*_bfd_error_handler
)
2744 (_("Attempt to do relocatable link with %s input and %s output"),
2745 bfd_get_target (input_bfd
), bfd_get_target (output_bfd
));
2746 bfd_set_error (bfd_error_wrong_format
);
2750 if (! generic_linker
)
2755 /* Get the canonical symbols. The generic linker will always
2756 have retrieved them by this point, but we are being called by
2757 a specific linker, presumably because we are linking
2758 different types of object files together. */
2759 if (! generic_link_read_symbols (input_bfd
))
2762 /* Since we have been called by a specific linker, rather than
2763 the generic linker, the values of the symbols will not be
2764 right. They will be the values as seen in the input file,
2765 not the values of the final link. We need to fix them up
2766 before we can relocate the section. */
2767 sympp
= _bfd_generic_link_get_symbols (input_bfd
);
2768 symppend
= sympp
+ _bfd_generic_link_get_symcount (input_bfd
);
2769 for (; sympp
< symppend
; sympp
++)
2772 struct bfd_link_hash_entry
*h
;
2776 if ((sym
->flags
& (BSF_INDIRECT
2781 || bfd_is_und_section (bfd_get_section (sym
))
2782 || bfd_is_com_section (bfd_get_section (sym
))
2783 || bfd_is_ind_section (bfd_get_section (sym
)))
2785 /* sym->udata may have been set by
2786 generic_link_add_symbol_list. */
2787 if (sym
->udata
.p
!= NULL
)
2789 else if (bfd_is_und_section (bfd_get_section (sym
)))
2790 h
= bfd_wrapped_link_hash_lookup (output_bfd
, info
,
2791 bfd_asymbol_name (sym
),
2792 FALSE
, FALSE
, TRUE
);
2794 h
= bfd_link_hash_lookup (info
->hash
,
2795 bfd_asymbol_name (sym
),
2796 FALSE
, FALSE
, TRUE
);
2798 set_symbol_from_hash (sym
, h
);
2803 /* Get and relocate the section contents. */
2804 sec_size
= (input_section
->rawsize
> input_section
->size
2805 ? input_section
->rawsize
2806 : input_section
->size
);
2807 contents
= bfd_malloc (sec_size
);
2808 if (contents
== NULL
&& sec_size
!= 0)
2810 new_contents
= (bfd_get_relocated_section_contents
2811 (output_bfd
, info
, link_order
, contents
, info
->relocatable
,
2812 _bfd_generic_link_get_symbols (input_bfd
)));
2816 /* Output the section contents. */
2817 loc
= input_section
->output_offset
* bfd_octets_per_byte (output_bfd
);
2818 if (! bfd_set_section_contents (output_bfd
, output_section
,
2819 new_contents
, loc
, input_section
->size
))
2822 if (contents
!= NULL
)
2827 if (contents
!= NULL
)
2832 /* A little routine to count the number of relocs in a link_order
2836 _bfd_count_link_order_relocs (struct bfd_link_order
*link_order
)
2838 register unsigned int c
;
2839 register struct bfd_link_order
*l
;
2842 for (l
= link_order
; l
!= NULL
; l
= l
->next
)
2844 if (l
->type
== bfd_section_reloc_link_order
2845 || l
->type
== bfd_symbol_reloc_link_order
)
2854 bfd_link_split_section
2857 bfd_boolean bfd_link_split_section (bfd *abfd, asection *sec);
2860 Return nonzero if @var{sec} should be split during a
2861 reloceatable or final link.
2863 .#define bfd_link_split_section(abfd, sec) \
2864 . BFD_SEND (abfd, _bfd_link_split_section, (abfd, sec))
2870 _bfd_generic_link_split_section (bfd
*abfd ATTRIBUTE_UNUSED
,
2871 asection
*sec ATTRIBUTE_UNUSED
)
2878 bfd_section_already_linked
2881 void bfd_section_already_linked (bfd *abfd, asection *sec,
2882 struct bfd_link_info *info);
2885 Check if @var{sec} has been already linked during a reloceatable
2888 .#define bfd_section_already_linked(abfd, sec, info) \
2889 . BFD_SEND (abfd, _section_already_linked, (abfd, sec, info))
2894 /* Sections marked with the SEC_LINK_ONCE flag should only be linked
2895 once into the output. This routine checks each section, and
2896 arrange to discard it if a section of the same name has already
2897 been linked. This code assumes that all relevant sections have the
2898 SEC_LINK_ONCE flag set; that is, it does not depend solely upon the
2899 section name. bfd_section_already_linked is called via
2900 bfd_map_over_sections. */
2902 /* The hash table. */
2904 static struct bfd_hash_table _bfd_section_already_linked_table
;
2906 /* Support routines for the hash table used by section_already_linked,
2907 initialize the table, traverse, lookup, fill in an entry and remove
2911 bfd_section_already_linked_table_traverse
2912 (bfd_boolean (*func
) (struct bfd_section_already_linked_hash_entry
*,
2913 void *), void *info
)
2915 bfd_hash_traverse (&_bfd_section_already_linked_table
,
2916 (bfd_boolean (*) (struct bfd_hash_entry
*,
2921 struct bfd_section_already_linked_hash_entry
*
2922 bfd_section_already_linked_table_lookup (const char *name
)
2924 return ((struct bfd_section_already_linked_hash_entry
*)
2925 bfd_hash_lookup (&_bfd_section_already_linked_table
, name
,
2930 bfd_section_already_linked_table_insert
2931 (struct bfd_section_already_linked_hash_entry
*already_linked_list
,
2934 struct bfd_section_already_linked
*l
;
2936 /* Allocate the memory from the same obstack as the hash table is
2938 l
= bfd_hash_allocate (&_bfd_section_already_linked_table
, sizeof *l
);
2940 l
->next
= already_linked_list
->entry
;
2941 already_linked_list
->entry
= l
;
2944 static struct bfd_hash_entry
*
2945 already_linked_newfunc (struct bfd_hash_entry
*entry ATTRIBUTE_UNUSED
,
2946 struct bfd_hash_table
*table
,
2947 const char *string ATTRIBUTE_UNUSED
)
2949 struct bfd_section_already_linked_hash_entry
*ret
=
2950 bfd_hash_allocate (table
, sizeof *ret
);
2958 bfd_section_already_linked_table_init (void)
2960 return bfd_hash_table_init_n (&_bfd_section_already_linked_table
,
2961 already_linked_newfunc
,
2962 sizeof (struct bfd_section_already_linked_hash_entry
),
2967 bfd_section_already_linked_table_free (void)
2969 bfd_hash_table_free (&_bfd_section_already_linked_table
);
2972 /* This is used on non-ELF inputs. */
2975 _bfd_generic_section_already_linked (bfd
*abfd
, asection
*sec
,
2976 struct bfd_link_info
*info ATTRIBUTE_UNUSED
)
2980 struct bfd_section_already_linked
*l
;
2981 struct bfd_section_already_linked_hash_entry
*already_linked_list
;
2984 if ((flags
& SEC_LINK_ONCE
) == 0)
2987 /* FIXME: When doing a relocatable link, we may have trouble
2988 copying relocations in other sections that refer to local symbols
2989 in the section being discarded. Those relocations will have to
2990 be converted somehow; as of this writing I'm not sure that any of
2991 the backends handle that correctly.
2993 It is tempting to instead not discard link once sections when
2994 doing a relocatable link (technically, they should be discarded
2995 whenever we are building constructors). However, that fails,
2996 because the linker winds up combining all the link once sections
2997 into a single large link once section, which defeats the purpose
2998 of having link once sections in the first place. */
3000 name
= bfd_get_section_name (abfd
, sec
);
3002 already_linked_list
= bfd_section_already_linked_table_lookup (name
);
3004 for (l
= already_linked_list
->entry
; l
!= NULL
; l
= l
->next
)
3006 bfd_boolean skip
= FALSE
;
3007 struct coff_comdat_info
*s_comdat
3008 = bfd_coff_get_comdat_section (abfd
, sec
);
3009 struct coff_comdat_info
*l_comdat
3010 = bfd_coff_get_comdat_section (l
->sec
->owner
, l
->sec
);
3012 /* We may have 3 different sections on the list: group section,
3013 comdat section and linkonce section. SEC may be a linkonce or
3014 comdat section. We always ignore group section. For non-COFF
3015 inputs, we also ignore comdat section.
3017 FIXME: Is that safe to match a linkonce section with a comdat
3018 section for COFF inputs? */
3019 if ((l
->sec
->flags
& SEC_GROUP
) != 0)
3021 else if (bfd_get_flavour (abfd
) == bfd_target_coff_flavour
)
3023 if (s_comdat
!= NULL
3025 && strcmp (s_comdat
->name
, l_comdat
->name
) != 0)
3028 else if (l_comdat
!= NULL
)
3033 /* The section has already been linked. See if we should
3035 switch (flags
& SEC_LINK_DUPLICATES
)
3040 case SEC_LINK_DUPLICATES_DISCARD
:
3043 case SEC_LINK_DUPLICATES_ONE_ONLY
:
3044 (*_bfd_error_handler
)
3045 (_("%B: warning: ignoring duplicate section `%A'\n"),
3049 case SEC_LINK_DUPLICATES_SAME_CONTENTS
:
3050 /* FIXME: We should really dig out the contents of both
3051 sections and memcmp them. The COFF/PE spec says that
3052 the Microsoft linker does not implement this
3053 correctly, so I'm not going to bother doing it
3056 case SEC_LINK_DUPLICATES_SAME_SIZE
:
3057 if (sec
->size
!= l
->sec
->size
)
3058 (*_bfd_error_handler
)
3059 (_("%B: warning: duplicate section `%A' has different size\n"),
3064 /* Set the output_section field so that lang_add_section
3065 does not create a lang_input_section structure for this
3066 section. Since there might be a symbol in the section
3067 being discarded, we must retain a pointer to the section
3068 which we are really going to use. */
3069 sec
->output_section
= bfd_abs_section_ptr
;
3070 sec
->kept_section
= l
->sec
;
3076 /* This is the first section with this name. Record it. */
3077 bfd_section_already_linked_table_insert (already_linked_list
, sec
);
3080 /* Convert symbols in excluded output sections to use a kept section. */
3083 fix_syms (struct bfd_link_hash_entry
*h
, void *data
)
3085 bfd
*obfd
= (bfd
*) data
;
3087 if (h
->type
== bfd_link_hash_warning
)
3090 if (h
->type
== bfd_link_hash_defined
3091 || h
->type
== bfd_link_hash_defweak
)
3093 asection
*s
= h
->u
.def
.section
;
3095 && s
->output_section
!= NULL
3096 && (s
->output_section
->flags
& SEC_EXCLUDE
) != 0
3097 && bfd_section_removed_from_list (obfd
, s
->output_section
))
3101 h
->u
.def
.value
+= s
->output_offset
+ s
->output_section
->vma
;
3103 /* Find preceding kept section. */
3104 for (op1
= s
->output_section
->prev
; op1
!= NULL
; op1
= op1
->prev
)
3105 if ((op1
->flags
& SEC_EXCLUDE
) == 0
3106 && !bfd_section_removed_from_list (obfd
, op1
))
3109 /* Find following kept section. Start at prev->next because
3110 other sections may have been added after S was removed. */
3111 if (s
->output_section
->prev
!= NULL
)
3112 op
= s
->output_section
->prev
->next
;
3114 op
= s
->output_section
->owner
->sections
;
3115 for (; op
!= NULL
; op
= op
->next
)
3116 if ((op
->flags
& SEC_EXCLUDE
) == 0
3117 && !bfd_section_removed_from_list (obfd
, op
))
3120 /* Choose better of two sections, based on flags. The idea
3121 is to choose a section that will be in the same segment
3122 as S would have been if it was kept. */
3126 op
= bfd_abs_section_ptr
;
3128 else if (op
== NULL
)
3130 else if (((op1
->flags
^ op
->flags
)
3131 & (SEC_ALLOC
| SEC_THREAD_LOCAL
)) != 0)
3133 if (((op
->flags
^ s
->flags
)
3134 & (SEC_ALLOC
| SEC_THREAD_LOCAL
)) != 0)
3137 else if (((op1
->flags
^ op
->flags
) & SEC_READONLY
) != 0)
3139 if (((op
->flags
^ s
->flags
) & SEC_READONLY
) != 0)
3142 else if (((op1
->flags
^ op
->flags
) & SEC_CODE
) != 0)
3144 if (((op
->flags
^ s
->flags
) & SEC_CODE
) != 0)
3149 /* Flags we care about are the same. Prefer the following
3150 section if that will result in a positive valued sym. */
3151 if (h
->u
.def
.value
< op
->vma
)
3155 h
->u
.def
.value
-= op
->vma
;
3156 h
->u
.def
.section
= op
;
3164 _bfd_fix_excluded_sec_syms (bfd
*obfd
, struct bfd_link_info
*info
)
3166 bfd_link_hash_traverse (info
->hash
, fix_syms
, obfd
);