* linker.c (_bfd_generic_link_add_one_symbol): Ignore
[binutils-gdb.git] / bfd / linker.c
1 /* linker.c -- BFD linker routines
2 Copyright (C) 1993, 1994 Free Software Foundation, Inc.
3 Written by Steve Chamberlain and Ian Lance Taylor, Cygnus Support
4
5 This file is part of BFD, the Binary File Descriptor library.
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
20
21 #include "bfd.h"
22 #include "sysdep.h"
23 #include "libbfd.h"
24 #include "bfdlink.h"
25 #include "genlink.h"
26
27 /*
28 SECTION
29 Linker Functions
30
31 @cindex Linker
32 The linker uses three special entry points in the BFD target
33 vector. It is not necessary to write special routines for
34 these entry points when creating a new BFD back end, since
35 generic versions are provided. However, writing them can
36 speed up linking and make it use significantly less runtime
37 memory.
38
39 The first routine creates a hash table used by the other
40 routines. The second routine adds the symbols from an object
41 file to the hash table. The third routine takes all the
42 object files and links them together to create the output
43 file. These routines are designed so that the linker proper
44 does not need to know anything about the symbols in the object
45 files that it is linking. The linker merely arranges the
46 sections as directed by the linker script and lets BFD handle
47 the details of symbols and relocs.
48
49 The second routine and third routines are passed a pointer to
50 a <<struct bfd_link_info>> structure (defined in
51 <<bfdlink.h>>) which holds information relevant to the link,
52 including the linker hash table (which was created by the
53 first routine) and a set of callback functions to the linker
54 proper.
55
56 The generic linker routines are in <<linker.c>>, and use the
57 header file <<genlink.h>>. As of this writing, the only back
58 ends which have implemented versions of these routines are
59 a.out (in <<aoutx.h>>) and ECOFF (in <<ecoff.c>>). The a.out
60 routines are used as examples throughout this section.
61
62 @menu
63 @* Creating a Linker Hash Table::
64 @* Adding Symbols to the Hash Table::
65 @* Performing the Final Link::
66 @end menu
67
68 INODE
69 Creating a Linker Hash Table, Adding Symbols to the Hash Table, Linker Functions, Linker Functions
70 SUBSECTION
71 Creating a linker hash table
72
73 @cindex _bfd_link_hash_table_create in target vector
74 @cindex target vector (_bfd_link_hash_table_create)
75 The linker routines must create a hash table, which must be
76 derived from <<struct bfd_link_hash_table>> described in
77 <<bfdlink.c>>. @xref{Hash Tables} for information on how to
78 create a derived hash table. This entry point is called using
79 the target vector of the linker output file.
80
81 The <<_bfd_link_hash_table_create>> entry point must allocate
82 and initialize an instance of the desired hash table. If the
83 back end does not require any additional information to be
84 stored with the entries in the hash table, the entry point may
85 simply create a <<struct bfd_link_hash_table>>. Most likely,
86 however, some additional information will be needed.
87
88 For example, with each entry in the hash table the a.out
89 linker keeps the index the symbol has in the final output file
90 (this index number is used so that when doing a relocateable
91 link the symbol index used in the output file can be quickly
92 filled in when copying over a reloc). The a.out linker code
93 defines the required structures and functions for a hash table
94 derived from <<struct bfd_link_hash_table>>. The a.out linker
95 hash table is created by the function
96 <<NAME(aout,link_hash_table_create)>>; it simply allocates
97 space for the hash table, initializes it, and returns a
98 pointer to it.
99
100 When writing the linker routines for a new back end, you will
101 generally not know exactly which fields will be required until
102 you have finished. You should simply create a new hash table
103 which defines no additional fields, and then simply add fields
104 as they become necessary.
105
106 INODE
107 Adding Symbols to the Hash Table, Performing the Final Link, Creating a Linker Hash Table, Linker Functions
108 SUBSECTION
109 Adding symbols to the hash table
110
111 @cindex _bfd_link_add_symbols in target vector
112 @cindex target vector (_bfd_link_add_symbols)
113 The linker proper will call the <<_bfd_link_add_symbols>>
114 entry point for each object file or archive which is to be
115 linked (typically these are the files named on the command
116 line, but some may also come from the linker script). The
117 entry point is responsible for examining the file. For an
118 object file, BFD must add any relevant symbol information to
119 the hash table. For an archive, BFD must determine which
120 elements of the archive should be used and adding them to the
121 link.
122
123 The a.out version of this entry point is
124 <<NAME(aout,link_add_symbols)>>.
125
126 @menu
127 @* Differing file formats::
128 @* Adding symbols from an object file::
129 @* Adding symbols from an archive::
130 @end menu
131
132 INODE
133 Differing file formats, Adding symbols from an object file, Adding Symbols to the Hash Table, Adding Symbols to the Hash Table
134 SUBSUBSECTION
135 Differing file formats
136
137 Normally all the files involved in a link will be of the same
138 format, but it is also possible to link together different
139 format object files, and the back end must support that. The
140 <<_bfd_link_add_symbols>> entry point is called via the target
141 vector of the file to be added. This has an important
142 consequence: the function may not assume that the hash table
143 is the type created by the corresponding
144 <<_bfd_link_hash_table_create>> vector. All the
145 <<_bfd_link_add_symbols>> function can assume about the hash
146 table is that it is derived from <<struct
147 bfd_link_hash_table>>.
148
149 Sometimes the <<_bfd_link_add_symbols>> function must store
150 some information in the hash table entry to be used by the
151 <<_bfd_final_link>> function. In such a case the <<creator>>
152 field of the hash table must be checked to make sure that the
153 hash table was created by an object file of the same format.
154
155 The <<_bfd_final_link>> routine must be prepared to handle a
156 hash entry without any extra information added by the
157 <<_bfd_link_add_symbols>> function. A hash entry without
158 extra information will also occur when the linker script
159 directs the linker to create a symbol. Note that, regardless
160 of how a hash table entry is added, all the fields will be
161 initialized to some sort of null value by the hash table entry
162 initialization function.
163
164 See <<ecoff_link_add_externals>> for an example of how to
165 check the <<creator>> field before saving information (in this
166 case, the ECOFF external symbol debugging information) in a
167 hash table entry.
168
169 INODE
170 Adding symbols from an object file, Adding symbols from an archive, Differing file formats, Adding Symbols to the Hash Table
171 SUBSUBSECTION
172 Adding symbols from an object file
173
174 When the <<_bfd_link_add_symbols>> routine is passed an object
175 file, it must add all externally visible symbols in that
176 object file to the hash table. The actual work of adding the
177 symbol to the hash table is normally handled by the function
178 <<_bfd_generic_link_add_one_symbol>>. The
179 <<_bfd_link_add_symbols>> routine is responsible for reading
180 all the symbols from the object file and passing the correct
181 information to <<_bfd_generic_link_add_one_symbol>>.
182
183 The <<_bfd_link_add_symbols>> routine should not use
184 <<bfd_canonicalize_symtab>> to read the symbols. The point of
185 providing this routine is to avoid the overhead of converting
186 the symbols into generic <<asymbol>> structures.
187
188 @findex _bfd_generic_link_add_one_symbol
189 <<_bfd_generic_link_add_one_symbol>> handles the details of
190 combining common symbols, warning about multiple definitions,
191 and so forth. It takes arguments which describe the symbol to
192 add, notably symbol flags, a section, and an offset. The
193 symbol flags include such things as <<BSF_WEAK>> or
194 <<BSF_INDIRECT>>. The section is a section in the object
195 file, or something like <<bfd_und_section_ptr>> for an undefined
196 symbol or <<bfd_com_section_ptr>> for a common symbol.
197
198 If the <<_bfd_final_link>> routine is also going to need to
199 read the symbol information, the <<_bfd_link_add_symbols>>
200 routine should save it somewhere attached to the object file
201 BFD. However, the information should only be saved if the
202 <<keep_memory>> field of the <<info>> argument is true, so
203 that the <<-no-keep-memory>> linker switch is effective.
204
205 The a.out function which adds symbols from an object file is
206 <<aout_link_add_object_symbols>>, and most of the interesting
207 work is in <<aout_link_add_symbols>>. The latter saves
208 pointers to the hash tables entries created by
209 <<_bfd_generic_link_add_one_symbol>> indexed by symbol number,
210 so that the <<_bfd_final_link>> routine does not have to call
211 the hash table lookup routine to locate the entry.
212
213 INODE
214 Adding symbols from an archive, , Adding symbols from an object file, Adding Symbols to the Hash Table
215 SUBSUBSECTION
216 Adding symbols from an archive
217
218 When the <<_bfd_link_add_symbols>> routine is passed an
219 archive, it must look through the symbols defined by the
220 archive and decide which elements of the archive should be
221 included in the link. For each such element it must call the
222 <<add_archive_element>> linker callback, and it must add the
223 symbols from the object file to the linker hash table.
224
225 @findex _bfd_generic_link_add_archive_symbols
226 In most cases the work of looking through the symbols in the
227 archive should be done by the
228 <<_bfd_generic_link_add_archive_symbols>> function. This
229 function builds a hash table from the archive symbol table and
230 looks through the list of undefined symbols to see which
231 elements should be included.
232 <<_bfd_generic_link_add_archive_symbols>> is passed a function
233 to call to make the final decision about adding an archive
234 element to the link and to do the actual work of adding the
235 symbols to the linker hash table.
236
237 The function passed to
238 <<_bfd_generic_link_add_archive_symbols>> must read the
239 symbols of the archive element and decide whether the archive
240 element should be included in the link. If the element is to
241 be included, the <<add_archive_element>> linker callback
242 routine must be called with the element as an argument, and
243 the elements symbols must be added to the linker hash table
244 just as though the element had itself been passed to the
245 <<_bfd_link_add_symbols>> function.
246
247 When the a.out <<_bfd_link_add_symbols>> function receives an
248 archive, it calls <<_bfd_generic_link_add_archive_symbols>>
249 passing <<aout_link_check_archive_element>> as the function
250 argument. <<aout_link_check_archive_element>> calls
251 <<aout_link_check_ar_symbols>>. If the latter decides to add
252 the element (an element is only added if it provides a real,
253 non-common, definition for a previously undefined or common
254 symbol) it calls the <<add_archive_element>> callback and then
255 <<aout_link_check_archive_element>> calls
256 <<aout_link_add_symbols>> to actually add the symbols to the
257 linker hash table.
258
259 The ECOFF back end is unusual in that it does not normally
260 call <<_bfd_generic_link_add_archive_symbols>>, because ECOFF
261 archives already contain a hash table of symbols. The ECOFF
262 back end searches the archive itself to avoid the overhead of
263 creating a new hash table.
264
265 INODE
266 Performing the Final Link, , Adding Symbols to the Hash Table, Linker Functions
267 SUBSECTION
268 Performing the final link
269
270 @cindex _bfd_link_final_link in target vector
271 @cindex target vector (_bfd_final_link)
272 When all the input files have been processed, the linker calls
273 the <<_bfd_final_link>> entry point of the output BFD. This
274 routine is responsible for producing the final output file,
275 which has several aspects. It must relocate the contents of
276 the input sections and copy the data into the output sections.
277 It must build an output symbol table including any local
278 symbols from the input files and the global symbols from the
279 hash table. When producing relocateable output, it must
280 modify the input relocs and write them into the output file.
281 There may also be object format dependent work to be done.
282
283 The linker will also call the <<write_object_contents>> entry
284 point when the BFD is closed. The two entry points must work
285 together in order to produce the correct output file.
286
287 The details of how this works are inevitably dependent upon
288 the specific object file format. The a.out
289 <<_bfd_final_link>> routine is <<NAME(aout,final_link)>>.
290
291 @menu
292 @* Information provided by the linker::
293 @* Relocating the section contents::
294 @* Writing the symbol table::
295 @end menu
296
297 INODE
298 Information provided by the linker, Relocating the section contents, Performing the Final Link, Performing the Final Link
299 SUBSUBSECTION
300 Information provided by the linker
301
302 Before the linker calls the <<_bfd_final_link>> entry point,
303 it sets up some data structures for the function to use.
304
305 The <<input_bfds>> field of the <<bfd_link_info>> structure
306 will point to a list of all the input files included in the
307 link. These files are linked through the <<link_next>> field
308 of the <<bfd>> structure.
309
310 Each section in the output file will have a list of
311 <<link_order>> structures attached to the <<link_order_head>>
312 field (the <<link_order>> structure is defined in
313 <<bfdlink.h>>). These structures describe how to create the
314 contents of the output section in terms of the contents of
315 various input sections, fill constants, and, eventually, other
316 types of information. They also describe relocs that must be
317 created by the BFD backend, but do not correspond to any input
318 file; this is used to support -Ur, which builds constructors
319 while generating a relocateable object file.
320
321 INODE
322 Relocating the section contents, Writing the symbol table, Information provided by the linker, Performing the Final Link
323 SUBSUBSECTION
324 Relocating the section contents
325
326 The <<_bfd_final_link>> function should look through the
327 <<link_order>> structures attached to each section of the
328 output file. Each <<link_order>> structure should either be
329 handled specially, or it should be passed to the function
330 <<_bfd_default_link_order>> which will do the right thing
331 (<<_bfd_default_link_order>> is defined in <<linker.c>>).
332
333 For efficiency, a <<link_order>> of type
334 <<bfd_indirect_link_order>> whose associated section belongs
335 to a BFD of the same format as the output BFD must be handled
336 specially. This type of <<link_order>> describes part of an
337 output section in terms of a section belonging to one of the
338 input files. The <<_bfd_final_link>> function should read the
339 contents of the section and any associated relocs, apply the
340 relocs to the section contents, and write out the modified
341 section contents. If performing a relocateable link, the
342 relocs themselves must also be modified and written out.
343
344 @findex _bfd_relocate_contents
345 @findex _bfd_final_link_relocate
346 The functions <<_bfd_relocate_contents>> and
347 <<_bfd_final_link_relocate>> provide some general support for
348 performing the actual relocations, notably overflow checking.
349 Their arguments include information about the symbol the
350 relocation is against and a <<reloc_howto_type>> argument
351 which describes the relocation to perform. These functions
352 are defined in <<reloc.c>>.
353
354 The a.out function which handles reading, relocating, and
355 writing section contents is <<aout_link_input_section>>. The
356 actual relocation is done in <<aout_link_input_section_std>>
357 and <<aout_link_input_section_ext>>.
358
359 INODE
360 Writing the symbol table, , Relocating the section contents, Performing the Final Link
361 SUBSUBSECTION
362 Writing the symbol table
363
364 The <<_bfd_final_link>> function must gather all the symbols
365 in the input files and write them out. It must also write out
366 all the symbols in the global hash table. This must be
367 controlled by the <<strip>> and <<discard>> fields of the
368 <<bfd_link_info>> structure.
369
370 The local symbols of the input files will not have been
371 entered into the linker hash table. The <<_bfd_final_link>>
372 routine must consider each input file and include the symbols
373 in the output file. It may be convenient to do this when
374 looking through the <<link_order>> structures, or it may be
375 done by stepping through the <<input_bfds>> list.
376
377 The <<_bfd_final_link>> routine must also traverse the global
378 hash table to gather all the externally visible symbols. It
379 is possible that most of the externally visible symbols may be
380 written out when considering the symbols of each input file,
381 but it is still necessary to traverse the hash table since the
382 linker script may have defined some symbols that are not in
383 any of the input files. The <<written>> field in the
384 <<bfd_link_hash_entry>> structure may be used to determine
385 which entries in the hash table have not already been written
386 out.
387
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.
395
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 prefix is described by the <<lprefix>> and
402 <<lprefix_len>> fields of the <<bfd_link_info>> structure.
403
404 The a.out backend handles symbols by calling
405 <<aout_link_write_symbols>> on each input BFD and then
406 traversing the global hash table with the function
407 <<aout_link_write_other_symbol>>. It builds a string table
408 while writing out the symbols, which is written to the output
409 file at the end of <<NAME(aout,final_link)>>.
410 */
411
412 static struct bfd_hash_entry *generic_link_hash_newfunc
413 PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *,
414 const char *));
415 static boolean generic_link_read_symbols
416 PARAMS ((bfd *));
417 static boolean generic_link_add_symbols
418 PARAMS ((bfd *, struct bfd_link_info *, boolean collect));
419 static boolean generic_link_add_object_symbols
420 PARAMS ((bfd *, struct bfd_link_info *, boolean collect));
421 static boolean generic_link_check_archive_element_no_collect
422 PARAMS ((bfd *, struct bfd_link_info *, boolean *pneeded));
423 static boolean generic_link_check_archive_element_collect
424 PARAMS ((bfd *, struct bfd_link_info *, boolean *pneeded));
425 static boolean generic_link_check_archive_element
426 PARAMS ((bfd *, struct bfd_link_info *, boolean *pneeded, boolean collect));
427 static boolean generic_link_add_symbol_list
428 PARAMS ((bfd *, struct bfd_link_info *, bfd_size_type count, asymbol **,
429 boolean collect));
430 static void set_symbol_from_hash
431 PARAMS ((asymbol *, struct bfd_link_hash_entry *));
432 static boolean generic_add_output_symbol
433 PARAMS ((bfd *, size_t *psymalloc, asymbol *));
434 static boolean default_fill_link_order
435 PARAMS ((bfd *, struct bfd_link_info *, asection *,
436 struct bfd_link_order *));
437 static boolean default_indirect_link_order
438 PARAMS ((bfd *, struct bfd_link_info *, asection *,
439 struct bfd_link_order *, boolean));
440
441 /* The link hash table structure is defined in bfdlink.h. It provides
442 a base hash table which the backend specific hash tables are built
443 upon. */
444
445 /* Routine to create an entry in the link hash table. */
446
447 struct bfd_hash_entry *
448 _bfd_link_hash_newfunc (entry, table, string)
449 struct bfd_hash_entry *entry;
450 struct bfd_hash_table *table;
451 const char *string;
452 {
453 struct bfd_link_hash_entry *ret = (struct bfd_link_hash_entry *) entry;
454
455 /* Allocate the structure if it has not already been allocated by a
456 subclass. */
457 if (ret == (struct bfd_link_hash_entry *) NULL)
458 ret = ((struct bfd_link_hash_entry *)
459 bfd_hash_allocate (table, sizeof (struct bfd_link_hash_entry)));
460 if (ret == (struct bfd_link_hash_entry *) NULL)
461 {
462 bfd_set_error (bfd_error_no_memory);
463 return NULL;
464 }
465
466 /* Call the allocation method of the superclass. */
467 ret = ((struct bfd_link_hash_entry *)
468 bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));
469
470 if (ret)
471 {
472 /* Initialize the local fields. */
473 ret->type = bfd_link_hash_new;
474 ret->next = NULL;
475 }
476
477 return (struct bfd_hash_entry *) ret;
478 }
479
480 /* Initialize a link hash table. The BFD argument is the one
481 responsible for creating this table. */
482
483 boolean
484 _bfd_link_hash_table_init (table, abfd, newfunc)
485 struct bfd_link_hash_table *table;
486 bfd *abfd;
487 struct bfd_hash_entry *(*newfunc) PARAMS ((struct bfd_hash_entry *,
488 struct bfd_hash_table *,
489 const char *));
490 {
491 table->creator = abfd->xvec;
492 table->undefs = NULL;
493 table->undefs_tail = NULL;
494 return bfd_hash_table_init (&table->table, newfunc);
495 }
496
497 /* Look up a symbol in a link hash table. If follow is true, we
498 follow bfd_link_hash_indirect and bfd_link_hash_warning links to
499 the real symbol. */
500
501 struct bfd_link_hash_entry *
502 bfd_link_hash_lookup (table, string, create, copy, follow)
503 struct bfd_link_hash_table *table;
504 const char *string;
505 boolean create;
506 boolean copy;
507 boolean follow;
508 {
509 struct bfd_link_hash_entry *ret;
510
511 ret = ((struct bfd_link_hash_entry *)
512 bfd_hash_lookup (&table->table, string, create, copy));
513
514 if (follow && ret != (struct bfd_link_hash_entry *) NULL)
515 {
516 while (ret->type == bfd_link_hash_indirect
517 || ret->type == bfd_link_hash_warning)
518 ret = ret->u.i.link;
519 }
520
521 return ret;
522 }
523
524 /* Traverse a generic link hash table. The only reason this is not a
525 macro is to do better type checking. This code presumes that an
526 argument passed as a struct bfd_hash_entry * may be caught as a
527 struct bfd_link_hash_entry * with no explicit cast required on the
528 call. */
529
530 void
531 bfd_link_hash_traverse (table, func, info)
532 struct bfd_link_hash_table *table;
533 boolean (*func) PARAMS ((struct bfd_link_hash_entry *, PTR));
534 PTR info;
535 {
536 bfd_hash_traverse (&table->table,
537 ((boolean (*) PARAMS ((struct bfd_hash_entry *, PTR)))
538 func),
539 info);
540 }
541
542 /* Add a symbol to the linker hash table undefs list. */
543
544 INLINE void
545 bfd_link_add_undef (table, h)
546 struct bfd_link_hash_table *table;
547 struct bfd_link_hash_entry *h;
548 {
549 BFD_ASSERT (h->next == NULL);
550 if (table->undefs_tail != (struct bfd_link_hash_entry *) NULL)
551 table->undefs_tail->next = h;
552 if (table->undefs == (struct bfd_link_hash_entry *) NULL)
553 table->undefs = h;
554 table->undefs_tail = h;
555 }
556 \f
557 /* Routine to create an entry in an generic link hash table. */
558
559 static struct bfd_hash_entry *
560 generic_link_hash_newfunc (entry, table, string)
561 struct bfd_hash_entry *entry;
562 struct bfd_hash_table *table;
563 const char *string;
564 {
565 struct generic_link_hash_entry *ret =
566 (struct generic_link_hash_entry *) entry;
567
568 /* Allocate the structure if it has not already been allocated by a
569 subclass. */
570 if (ret == (struct generic_link_hash_entry *) NULL)
571 ret = ((struct generic_link_hash_entry *)
572 bfd_hash_allocate (table, sizeof (struct generic_link_hash_entry)));
573 if (ret == (struct generic_link_hash_entry *) NULL)
574 {
575 bfd_set_error (bfd_error_no_memory);
576 return NULL;
577 }
578
579 /* Call the allocation method of the superclass. */
580 ret = ((struct generic_link_hash_entry *)
581 _bfd_link_hash_newfunc ((struct bfd_hash_entry *) ret,
582 table, string));
583
584 if (ret)
585 {
586 /* Set local fields. */
587 ret->written = false;
588 ret->sym = NULL;
589 }
590
591 return (struct bfd_hash_entry *) ret;
592 }
593
594 /* Create an generic link hash table. */
595
596 struct bfd_link_hash_table *
597 _bfd_generic_link_hash_table_create (abfd)
598 bfd *abfd;
599 {
600 struct generic_link_hash_table *ret;
601
602 ret = ((struct generic_link_hash_table *)
603 malloc (sizeof (struct generic_link_hash_table)));
604 if (!ret)
605 {
606 bfd_set_error (bfd_error_no_memory);
607 return (struct bfd_link_hash_table *) NULL;
608 }
609 if (! _bfd_link_hash_table_init (&ret->root, abfd,
610 generic_link_hash_newfunc))
611 {
612 free (ret);
613 return (struct bfd_link_hash_table *) NULL;
614 }
615 return &ret->root;
616 }
617
618 /* Grab the symbols for an object file when doing a generic link. We
619 store the symbols in the outsymbols field. We need to keep them
620 around for the entire link to ensure that we only read them once.
621 If we read them multiple times, we might wind up with relocs and
622 the hash table pointing to different instances of the symbol
623 structure. */
624
625 static boolean
626 generic_link_read_symbols (abfd)
627 bfd *abfd;
628 {
629 if (abfd->outsymbols == (asymbol **) NULL)
630 {
631 long symsize;
632 long symcount;
633
634 symsize = bfd_get_symtab_upper_bound (abfd);
635 if (symsize < 0)
636 return false;
637 abfd->outsymbols = (asymbol **) bfd_alloc (abfd, symsize);
638 if (abfd->outsymbols == NULL && symsize != 0)
639 {
640 bfd_set_error (bfd_error_no_memory);
641 return false;
642 }
643 symcount = bfd_canonicalize_symtab (abfd, abfd->outsymbols);
644 if (symcount < 0)
645 return false;
646 abfd->symcount = symcount;
647 }
648
649 return true;
650 }
651 \f
652 /* Generic function to add symbols to from an object file to the
653 global hash table. This version does not automatically collect
654 constructors by name. */
655
656 boolean
657 _bfd_generic_link_add_symbols (abfd, info)
658 bfd *abfd;
659 struct bfd_link_info *info;
660 {
661 return generic_link_add_symbols (abfd, info, false);
662 }
663
664 /* Generic function to add symbols from an object file to the global
665 hash table. This version automatically collects constructors by
666 name, as the collect2 program does. It should be used for any
667 target which does not provide some other mechanism for setting up
668 constructors and destructors; these are approximately those targets
669 for which gcc uses collect2 and do not support stabs. */
670
671 boolean
672 _bfd_generic_link_add_symbols_collect (abfd, info)
673 bfd *abfd;
674 struct bfd_link_info *info;
675 {
676 return generic_link_add_symbols (abfd, info, true);
677 }
678
679 /* Add symbols from an object file to the global hash table. */
680
681 static boolean
682 generic_link_add_symbols (abfd, info, collect)
683 bfd *abfd;
684 struct bfd_link_info *info;
685 boolean collect;
686 {
687 boolean ret;
688
689 switch (bfd_get_format (abfd))
690 {
691 case bfd_object:
692 ret = generic_link_add_object_symbols (abfd, info, collect);
693 break;
694 case bfd_archive:
695 ret = (_bfd_generic_link_add_archive_symbols
696 (abfd, info,
697 (collect
698 ? generic_link_check_archive_element_collect
699 : generic_link_check_archive_element_no_collect)));
700 break;
701 default:
702 bfd_set_error (bfd_error_wrong_format);
703 ret = false;
704 }
705
706 return ret;
707 }
708
709 /* Add symbols from an object file to the global hash table. */
710
711 static boolean
712 generic_link_add_object_symbols (abfd, info, collect)
713 bfd *abfd;
714 struct bfd_link_info *info;
715 boolean collect;
716 {
717 if (! generic_link_read_symbols (abfd))
718 return false;
719 return generic_link_add_symbol_list (abfd, info,
720 _bfd_generic_link_get_symcount (abfd),
721 _bfd_generic_link_get_symbols (abfd),
722 collect);
723 }
724 \f
725 /* We build a hash table of all symbols defined in an archive. */
726
727 /* An archive symbol may be defined by multiple archive elements.
728 This linked list is used to hold the elements. */
729
730 struct archive_list
731 {
732 struct archive_list *next;
733 int indx;
734 };
735
736 /* An entry in an archive hash table. */
737
738 struct archive_hash_entry
739 {
740 struct bfd_hash_entry root;
741 /* Where the symbol is defined. */
742 struct archive_list *defs;
743 };
744
745 /* An archive hash table itself. */
746
747 struct archive_hash_table
748 {
749 struct bfd_hash_table table;
750 };
751
752 static struct bfd_hash_entry *archive_hash_newfunc
753 PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *));
754 static boolean archive_hash_table_init
755 PARAMS ((struct archive_hash_table *,
756 struct bfd_hash_entry *(*) (struct bfd_hash_entry *,
757 struct bfd_hash_table *,
758 const char *)));
759
760 /* Create a new entry for an archive hash table. */
761
762 static struct bfd_hash_entry *
763 archive_hash_newfunc (entry, table, string)
764 struct bfd_hash_entry *entry;
765 struct bfd_hash_table *table;
766 const char *string;
767 {
768 struct archive_hash_entry *ret = (struct archive_hash_entry *) entry;
769
770 /* Allocate the structure if it has not already been allocated by a
771 subclass. */
772 if (ret == (struct archive_hash_entry *) NULL)
773 ret = ((struct archive_hash_entry *)
774 bfd_hash_allocate (table, sizeof (struct archive_hash_entry)));
775 if (ret == (struct archive_hash_entry *) NULL)
776 {
777 bfd_set_error (bfd_error_no_memory);
778 return NULL;
779 }
780
781 /* Call the allocation method of the superclass. */
782 ret = ((struct archive_hash_entry *)
783 bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));
784
785 if (ret)
786 {
787 /* Initialize the local fields. */
788 ret->defs = (struct archive_list *) NULL;
789 }
790
791 return (struct bfd_hash_entry *) ret;
792 }
793
794 /* Initialize an archive hash table. */
795
796 static boolean
797 archive_hash_table_init (table, newfunc)
798 struct archive_hash_table *table;
799 struct bfd_hash_entry *(*newfunc) PARAMS ((struct bfd_hash_entry *,
800 struct bfd_hash_table *,
801 const char *));
802 {
803 return bfd_hash_table_init (&table->table, newfunc);
804 }
805
806 /* Look up an entry in an archive hash table. */
807
808 #define archive_hash_lookup(t, string, create, copy) \
809 ((struct archive_hash_entry *) \
810 bfd_hash_lookup (&(t)->table, (string), (create), (copy)))
811
812 /* Allocate space in an archive hash table. */
813
814 #define archive_hash_allocate(t, size) bfd_hash_allocate (&(t)->table, (size))
815
816 /* Free an archive hash table. */
817
818 #define archive_hash_table_free(t) bfd_hash_table_free (&(t)->table)
819
820 /* Generic function to add symbols from an archive file to the global
821 hash file. This function presumes that the archive symbol table
822 has already been read in (this is normally done by the
823 bfd_check_format entry point). It looks through the undefined and
824 common symbols and searches the archive symbol table for them. If
825 it finds an entry, it includes the associated object file in the
826 link.
827
828 The old linker looked through the archive symbol table for
829 undefined symbols. We do it the other way around, looking through
830 undefined symbols for symbols defined in the archive. The
831 advantage of the newer scheme is that we only have to look through
832 the list of undefined symbols once, whereas the old method had to
833 re-search the symbol table each time a new object file was added.
834
835 The CHECKFN argument is used to see if an object file should be
836 included. CHECKFN should set *PNEEDED to true if the object file
837 should be included, and must also call the bfd_link_info
838 add_archive_element callback function and handle adding the symbols
839 to the global hash table. CHECKFN should only return false if some
840 sort of error occurs.
841
842 For some formats, such as a.out, it is possible to look through an
843 object file but not actually include it in the link. The
844 archive_pass field in a BFD is used to avoid checking the symbols
845 of an object files too many times. When an object is included in
846 the link, archive_pass is set to -1. If an object is scanned but
847 not included, archive_pass is set to the pass number. The pass
848 number is incremented each time a new object file is included. The
849 pass number is used because when a new object file is included it
850 may create new undefined symbols which cause a previously examined
851 object file to be included. */
852
853 boolean
854 _bfd_generic_link_add_archive_symbols (abfd, info, checkfn)
855 bfd *abfd;
856 struct bfd_link_info *info;
857 boolean (*checkfn) PARAMS ((bfd *, struct bfd_link_info *,
858 boolean *pneeded));
859 {
860 carsym *arsyms;
861 carsym *arsym_end;
862 register carsym *arsym;
863 int pass;
864 struct archive_hash_table arsym_hash;
865 int indx;
866 struct bfd_link_hash_entry **pundef;
867
868 if (! bfd_has_map (abfd))
869 {
870 /* An empty archive is a special case. */
871 if (bfd_openr_next_archived_file (abfd, (bfd *) NULL) == NULL)
872 return true;
873 bfd_set_error (bfd_error_no_symbols);
874 return false;
875 }
876
877 arsyms = bfd_ardata (abfd)->symdefs;
878 arsym_end = arsyms + bfd_ardata (abfd)->symdef_count;
879
880 /* In order to quickly determine whether an symbol is defined in
881 this archive, we build a hash table of the symbols. */
882 if (! archive_hash_table_init (&arsym_hash, archive_hash_newfunc))
883 return false;
884 for (arsym = arsyms, indx = 0; arsym < arsym_end; arsym++, indx++)
885 {
886 struct archive_hash_entry *arh;
887 struct archive_list *l, **pp;
888
889 arh = archive_hash_lookup (&arsym_hash, arsym->name, true, false);
890 if (arh == (struct archive_hash_entry *) NULL)
891 goto error_return;
892 l = ((struct archive_list *)
893 archive_hash_allocate (&arsym_hash, sizeof (struct archive_list)));
894 if (l == NULL)
895 goto error_return;
896 l->indx = indx;
897 for (pp = &arh->defs;
898 *pp != (struct archive_list *) NULL;
899 pp = &(*pp)->next)
900 ;
901 *pp = l;
902 l->next = NULL;
903 }
904
905 /* The archive_pass field in the archive itself is used to
906 initialize PASS, sine we may search the same archive multiple
907 times. */
908 pass = abfd->archive_pass + 1;
909
910 /* New undefined symbols are added to the end of the list, so we
911 only need to look through it once. */
912 pundef = &info->hash->undefs;
913 while (*pundef != (struct bfd_link_hash_entry *) NULL)
914 {
915 struct bfd_link_hash_entry *h;
916 struct archive_hash_entry *arh;
917 struct archive_list *l;
918
919 h = *pundef;
920
921 /* When a symbol is defined, it is not necessarily removed from
922 the list. */
923 if (h->type != bfd_link_hash_undefined
924 && h->type != bfd_link_hash_common)
925 {
926 /* Remove this entry from the list, for general cleanliness
927 and because we are going to look through the list again
928 if we search any more libraries. We can't remove the
929 entry if it is the tail, because that would lose any
930 entries we add to the list later on (it would also cause
931 us to lose track of whether the symbol has been
932 referenced). */
933 if (*pundef != info->hash->undefs_tail)
934 *pundef = (*pundef)->next;
935 else
936 pundef = &(*pundef)->next;
937 continue;
938 }
939
940 /* Look for this symbol in the archive symbol map. */
941 arh = archive_hash_lookup (&arsym_hash, h->root.string, false, false);
942 if (arh == (struct archive_hash_entry *) NULL)
943 {
944 pundef = &(*pundef)->next;
945 continue;
946 }
947
948 /* Look at all the objects which define this symbol. */
949 for (l = arh->defs; l != (struct archive_list *) NULL; l = l->next)
950 {
951 bfd *element;
952 boolean needed;
953
954 /* If the symbol has gotten defined along the way, quit. */
955 if (h->type != bfd_link_hash_undefined
956 && h->type != bfd_link_hash_common)
957 break;
958
959 element = bfd_get_elt_at_index (abfd, l->indx);
960 if (element == (bfd *) NULL)
961 goto error_return;
962
963 /* If we've already included this element, or if we've
964 already checked it on this pass, continue. */
965 if (element->archive_pass == -1
966 || element->archive_pass == pass)
967 continue;
968
969 /* If we can't figure this element out, just ignore it. */
970 if (! bfd_check_format (element, bfd_object))
971 {
972 element->archive_pass = -1;
973 continue;
974 }
975
976 /* CHECKFN will see if this element should be included, and
977 go ahead and include it if appropriate. */
978 if (! (*checkfn) (element, info, &needed))
979 goto error_return;
980
981 if (! needed)
982 element->archive_pass = pass;
983 else
984 {
985 element->archive_pass = -1;
986
987 /* Increment the pass count to show that we may need to
988 recheck object files which were already checked. */
989 ++pass;
990 }
991 }
992
993 pundef = &(*pundef)->next;
994 }
995
996 archive_hash_table_free (&arsym_hash);
997
998 /* Save PASS in case we are called again. */
999 abfd->archive_pass = pass;
1000
1001 return true;
1002
1003 error_return:
1004 archive_hash_table_free (&arsym_hash);
1005 return false;
1006 }
1007 \f
1008 /* See if we should include an archive element. This version is used
1009 when we do not want to automatically collect constructors based on
1010 the symbol name, presumably because we have some other mechanism
1011 for finding them. */
1012
1013 static boolean
1014 generic_link_check_archive_element_no_collect (abfd, info, pneeded)
1015 bfd *abfd;
1016 struct bfd_link_info *info;
1017 boolean *pneeded;
1018 {
1019 return generic_link_check_archive_element (abfd, info, pneeded, false);
1020 }
1021
1022 /* See if we should include an archive element. This version is used
1023 when we want to automatically collect constructors based on the
1024 symbol name, as collect2 does. */
1025
1026 static boolean
1027 generic_link_check_archive_element_collect (abfd, info, pneeded)
1028 bfd *abfd;
1029 struct bfd_link_info *info;
1030 boolean *pneeded;
1031 {
1032 return generic_link_check_archive_element (abfd, info, pneeded, true);
1033 }
1034
1035 /* See if we should include an archive element. Optionally collect
1036 constructors. */
1037
1038 static boolean
1039 generic_link_check_archive_element (abfd, info, pneeded, collect)
1040 bfd *abfd;
1041 struct bfd_link_info *info;
1042 boolean *pneeded;
1043 boolean collect;
1044 {
1045 asymbol **pp, **ppend;
1046
1047 *pneeded = false;
1048
1049 if (! generic_link_read_symbols (abfd))
1050 return false;
1051
1052 pp = _bfd_generic_link_get_symbols (abfd);
1053 ppend = pp + _bfd_generic_link_get_symcount (abfd);
1054 for (; pp < ppend; pp++)
1055 {
1056 asymbol *p;
1057 struct bfd_link_hash_entry *h;
1058
1059 p = *pp;
1060
1061 /* We are only interested in globally visible symbols. */
1062 if (! bfd_is_com_section (p->section)
1063 && (p->flags & (BSF_GLOBAL | BSF_INDIRECT | BSF_WEAK)) == 0)
1064 continue;
1065
1066 /* We are only interested if we know something about this
1067 symbol, and it is undefined or common. An undefined weak
1068 symbol (type bfd_link_hash_weak) is not considered to be a
1069 reference when pulling files out of an archive. See the SVR4
1070 ABI, p. 4-27. */
1071 h = bfd_link_hash_lookup (info->hash, bfd_asymbol_name (p), false,
1072 false, true);
1073 if (h == (struct bfd_link_hash_entry *) NULL
1074 || (h->type != bfd_link_hash_undefined
1075 && h->type != bfd_link_hash_common))
1076 continue;
1077
1078 /* P is a symbol we are looking for. */
1079
1080 if (! bfd_is_com_section (p->section))
1081 {
1082 bfd_size_type symcount;
1083 asymbol **symbols;
1084
1085 /* This object file defines this symbol, so pull it in. */
1086 if (! (*info->callbacks->add_archive_element) (info, abfd,
1087 bfd_asymbol_name (p)))
1088 return false;
1089 symcount = _bfd_generic_link_get_symcount (abfd);
1090 symbols = _bfd_generic_link_get_symbols (abfd);
1091 if (! generic_link_add_symbol_list (abfd, info, symcount,
1092 symbols, collect))
1093 return false;
1094 *pneeded = true;
1095 return true;
1096 }
1097
1098 /* P is a common symbol. */
1099
1100 if (h->type == bfd_link_hash_undefined)
1101 {
1102 bfd *symbfd;
1103 bfd_vma size;
1104 unsigned int power;
1105
1106 symbfd = h->u.undef.abfd;
1107 if (symbfd == (bfd *) NULL)
1108 {
1109 /* This symbol was created as undefined from outside
1110 BFD. We assume that we should link in the object
1111 file. This is for the -u option in the linker. */
1112 if (! (*info->callbacks->add_archive_element)
1113 (info, abfd, bfd_asymbol_name (p)))
1114 return false;
1115 *pneeded = true;
1116 return true;
1117 }
1118
1119 /* Turn the symbol into a common symbol but do not link in
1120 the object file. This is how a.out works. Object
1121 formats that require different semantics must implement
1122 this function differently. This symbol is already on the
1123 undefs list. We add the section to a common section
1124 attached to symbfd to ensure that it is in a BFD which
1125 will be linked in. */
1126 h->type = bfd_link_hash_common;
1127
1128 size = bfd_asymbol_value (p);
1129 h->u.c.size = size;
1130 if (h->u.c.size != size)
1131 {
1132 /* The size did not fit in the bitfield. */
1133 bfd_set_error (bfd_error_bad_value);
1134 return false;
1135 }
1136
1137 power = bfd_log2 (size);
1138 if (power > 4)
1139 power = 4;
1140 h->u.c.alignment_power = power;
1141
1142 if (p->section == bfd_com_section_ptr)
1143 h->u.c.section = bfd_make_section_old_way (symbfd, "COMMON");
1144 else
1145 h->u.c.section = bfd_make_section_old_way (symbfd,
1146 p->section->name);
1147 h->u.c.section->flags = SEC_ALLOC;
1148 }
1149 else
1150 {
1151 /* Adjust the size of the common symbol if necessary. This
1152 is how a.out works. Object formats that require
1153 different semantics must implement this function
1154 differently. */
1155 if (bfd_asymbol_value (p) > h->u.c.size)
1156 h->u.c.size = bfd_asymbol_value (p);
1157 }
1158 }
1159
1160 /* This archive element is not needed. */
1161 return true;
1162 }
1163
1164 /* Add the symbols from an object file to the global hash table. ABFD
1165 is the object file. INFO is the linker information. SYMBOL_COUNT
1166 is the number of symbols. SYMBOLS is the list of symbols. COLLECT
1167 is true if constructors should be automatically collected by name
1168 as is done by collect2. */
1169
1170 static boolean
1171 generic_link_add_symbol_list (abfd, info, symbol_count, symbols, collect)
1172 bfd *abfd;
1173 struct bfd_link_info *info;
1174 bfd_size_type symbol_count;
1175 asymbol **symbols;
1176 boolean collect;
1177 {
1178 asymbol **pp, **ppend;
1179
1180 pp = symbols;
1181 ppend = symbols + symbol_count;
1182 for (; pp < ppend; pp++)
1183 {
1184 asymbol *p;
1185
1186 p = *pp;
1187
1188 if ((p->flags & (BSF_INDIRECT
1189 | BSF_WARNING
1190 | BSF_GLOBAL
1191 | BSF_CONSTRUCTOR
1192 | BSF_WEAK)) != 0
1193 || bfd_is_und_section (bfd_get_section (p))
1194 || bfd_is_com_section (bfd_get_section (p))
1195 || bfd_is_ind_section (bfd_get_section (p)))
1196 {
1197 const char *name;
1198 const char *string;
1199 struct generic_link_hash_entry *h;
1200
1201 name = bfd_asymbol_name (p);
1202 if ((p->flags & BSF_INDIRECT) != 0
1203 || bfd_is_ind_section (p->section))
1204 string = bfd_asymbol_name ((asymbol *) p->value);
1205 else if ((p->flags & BSF_WARNING) != 0)
1206 {
1207 /* The name of P is actually the warning string, and the
1208 value is actually a pointer to the symbol to warn
1209 about. */
1210 string = name;
1211 name = bfd_asymbol_name ((asymbol *) p->value);
1212 }
1213 else
1214 string = NULL;
1215
1216 h = NULL;
1217 if (! (_bfd_generic_link_add_one_symbol
1218 (info, abfd, name, p->flags, bfd_get_section (p),
1219 p->value, string, false, collect,
1220 (struct bfd_link_hash_entry **) &h)))
1221 return false;
1222
1223 /* Save the BFD symbol so that we don't lose any backend
1224 specific information that may be attached to it. We only
1225 want this one if it gives more information than the
1226 existing one; we don't want to replace a defined symbol
1227 with an undefined one. This routine may be called with a
1228 hash table other than the generic hash table, so we only
1229 do this if we are certain that the hash table is a
1230 generic one. */
1231 if (info->hash->creator == abfd->xvec)
1232 {
1233 if (h->sym == (asymbol *) NULL
1234 || (! bfd_is_und_section (bfd_get_section (p))
1235 && (! bfd_is_com_section (bfd_get_section (p))
1236 || bfd_is_und_section (bfd_get_section (h->sym)))))
1237 {
1238 h->sym = p;
1239 /* BSF_OLD_COMMON is a hack to support COFF reloc
1240 reading, and it should go away when the COFF
1241 linker is switched to the new version. */
1242 if (bfd_is_com_section (bfd_get_section (p)))
1243 p->flags |= BSF_OLD_COMMON;
1244 }
1245
1246 /* Store a back pointer from the symbol to the hash
1247 table entry for the benefit of relaxation code until
1248 it gets rewritten to not use asymbol structures.
1249 Setting this is also used to check whether these
1250 symbols were set up by the generic linker. */
1251 p->udata.p = (PTR) h;
1252 }
1253 }
1254 }
1255
1256 return true;
1257 }
1258 \f
1259 /* We use a state table to deal with adding symbols from an object
1260 file. The first index into the state table describes the symbol
1261 from the object file. The second index into the state table is the
1262 type of the symbol in the hash table. */
1263
1264 /* The symbol from the object file is turned into one of these row
1265 values. */
1266
1267 enum link_row
1268 {
1269 UNDEF_ROW, /* Undefined. */
1270 UNDEFW_ROW, /* Weak undefined. */
1271 DEF_ROW, /* Defined. */
1272 DEFW_ROW, /* Weak defined. */
1273 COMMON_ROW, /* Common. */
1274 INDR_ROW, /* Indirect. */
1275 WARN_ROW, /* Warning. */
1276 SET_ROW /* Member of set. */
1277 };
1278
1279 /* apparently needed for Hitachi 3050R(HI-UX/WE2)? */
1280 #undef FAIL
1281
1282 /* The actions to take in the state table. */
1283
1284 enum link_action
1285 {
1286 FAIL, /* Abort. */
1287 UND, /* Mark symbol undefined. */
1288 WEAK, /* Mark symbol weak undefined. */
1289 DEF, /* Mark symbol defined. */
1290 COM, /* Mark symbol common. */
1291 REF, /* Mark defined symbol referenced. */
1292 CREF, /* Possibly warn about common reference to defined symbol. */
1293 CDEF, /* Define existing common symbol. */
1294 NOACT, /* No action. */
1295 BIG, /* Mark symbol common using largest size. */
1296 MDEF, /* Multiple definition error. */
1297 MIND, /* Multiple indirect symbols. */
1298 IND, /* Make indirect symbol. */
1299 CIND, /* Make indirect symbol from existing common symbol. */
1300 SET, /* Add value to set. */
1301 MWARN, /* Make warning symbol. */
1302 WARN, /* Issue warning. */
1303 CWARN, /* Warn if referenced, else MWARN. */
1304 CYCLE, /* Repeat with symbol pointed to. */
1305 REFC, /* Mark indirect symbol referenced and then CYCLE. */
1306 WARNC /* Issue warning and then CYCLE. */
1307 };
1308
1309 /* The state table itself. The first index is a link_row and the
1310 second index is a bfd_link_hash_type. */
1311
1312 static const enum link_action link_action[8][7] =
1313 {
1314 /* current\prev new undef weak def com indr warn */
1315 /* UNDEF_ROW */ {UND, NOACT, NOACT, REF, NOACT, REFC, WARNC },
1316 /* UNDEFW_ROW */ {WEAK, WEAK, NOACT, REF, NOACT, REFC, WARNC },
1317 /* DEF_ROW */ {DEF, DEF, DEF, MDEF, CDEF, MDEF, CYCLE },
1318 /* DEFW_ROW */ {DEF, DEF, DEF, NOACT, NOACT, NOACT, CYCLE },
1319 /* COMMON_ROW */ {COM, COM, COM, CREF, BIG, CREF, WARNC },
1320 /* INDR_ROW */ {IND, IND, IND, MDEF, CIND, MIND, CYCLE },
1321 /* WARN_ROW */ {MWARN, WARN, WARN, CWARN, WARN, CWARN, CYCLE },
1322 /* SET_ROW */ {SET, SET, SET, SET, SET, CYCLE, CYCLE }
1323 };
1324
1325 /* Most of the entries in the LINK_ACTION table are straightforward,
1326 but a few are somewhat subtle.
1327
1328 A reference to an indirect symbol (UNDEF_ROW/indr or
1329 UNDEFW_ROW/indr) is counted as a reference both to the indirect
1330 symbol and to the symbol the indirect symbol points to.
1331
1332 A reference to a warning symbol (UNDEF_ROW/warn or UNDEFW_ROW/warn)
1333 causes the warning to be issued.
1334
1335 A common definition of an indirect symbol (COMMON_ROW/indr) is
1336 treated as a multiple definition error. Likewise for an indirect
1337 definition of a common symbol (INDR_ROW/com).
1338
1339 An indirect definition of a warning (INDR_ROW/warn) does not cause
1340 the warning to be issued.
1341
1342 If a warning is created for an indirect symbol (WARN_ROW/indr) no
1343 warning is created for the symbol the indirect symbol points to.
1344
1345 Adding an entry to a set does not count as a reference to a set,
1346 and no warning is issued (SET_ROW/warn). */
1347
1348 /* Add a symbol to the global hash table.
1349 ABFD is the BFD the symbol comes from.
1350 NAME is the name of the symbol.
1351 FLAGS is the BSF_* bits associated with the symbol.
1352 SECTION is the section in which the symbol is defined; this may be
1353 bfd_und_section_ptr or bfd_com_section_ptr.
1354 VALUE is the value of the symbol, relative to the section.
1355 STRING is used for either an indirect symbol, in which case it is
1356 the name of the symbol to indirect to, or a warning symbol, in
1357 which case it is the warning string.
1358 COPY is true if NAME or STRING must be copied into locally
1359 allocated memory if they need to be saved.
1360 COLLECT is true if we should automatically collect gcc constructor
1361 or destructor names as collect2 does.
1362 HASHP, if not NULL, is a place to store the created hash table
1363 entry; if *HASHP is not NULL, the caller has already looked up
1364 the hash table entry, and stored it in *HASHP. */
1365
1366 boolean
1367 _bfd_generic_link_add_one_symbol (info, abfd, name, flags, section, value,
1368 string, copy, collect, hashp)
1369 struct bfd_link_info *info;
1370 bfd *abfd;
1371 const char *name;
1372 flagword flags;
1373 asection *section;
1374 bfd_vma value;
1375 const char *string;
1376 boolean copy;
1377 boolean collect;
1378 struct bfd_link_hash_entry **hashp;
1379 {
1380 enum link_row row;
1381 struct bfd_link_hash_entry *h;
1382 boolean cycle;
1383
1384 if (bfd_is_ind_section (section)
1385 || (flags & BSF_INDIRECT) != 0)
1386 row = INDR_ROW;
1387 else if ((flags & BSF_WARNING) != 0)
1388 row = WARN_ROW;
1389 else if ((flags & BSF_CONSTRUCTOR) != 0)
1390 row = SET_ROW;
1391 else if (bfd_is_und_section (section))
1392 {
1393 if ((flags & BSF_WEAK) != 0)
1394 row = UNDEFW_ROW;
1395 else
1396 row = UNDEF_ROW;
1397 }
1398 else if ((flags & BSF_WEAK) != 0)
1399 row = DEFW_ROW;
1400 else if (bfd_is_com_section (section))
1401 row = COMMON_ROW;
1402 else
1403 row = DEF_ROW;
1404
1405 if (hashp != NULL && *hashp != NULL)
1406 {
1407 h = *hashp;
1408 BFD_ASSERT (strcmp (h->root.string, name) == 0);
1409 }
1410 else
1411 {
1412 h = bfd_link_hash_lookup (info->hash, name, true, copy, false);
1413 if (h == NULL)
1414 {
1415 if (hashp != NULL)
1416 *hashp = NULL;
1417 return false;
1418 }
1419 }
1420
1421 if (info->notice_hash != (struct bfd_hash_table *) NULL
1422 && (bfd_hash_lookup (info->notice_hash, name, false, false)
1423 != (struct bfd_hash_entry *) NULL))
1424 {
1425 if (! (*info->callbacks->notice) (info, name, abfd, section, value))
1426 return false;
1427 }
1428
1429 if (hashp != (struct bfd_link_hash_entry **) NULL)
1430 *hashp = h;
1431
1432 do
1433 {
1434 enum link_action action;
1435
1436 cycle = false;
1437 action = link_action[(int) row][(int) h->type];
1438 switch (action)
1439 {
1440 case FAIL:
1441 abort ();
1442
1443 case NOACT:
1444 /* Do nothing. */
1445 break;
1446
1447 case UND:
1448 /* Make a new undefined symbol. */
1449 h->type = bfd_link_hash_undefined;
1450 h->u.undef.abfd = abfd;
1451 bfd_link_add_undef (info->hash, h);
1452 break;
1453
1454 case WEAK:
1455 /* Make a new weak undefined symbol. */
1456 h->type = bfd_link_hash_weak;
1457 h->u.undef.abfd = abfd;
1458 break;
1459
1460 case CDEF:
1461 /* We have found a definition for a symbol which was
1462 previously common. */
1463 BFD_ASSERT (h->type == bfd_link_hash_common);
1464 if (! ((*info->callbacks->multiple_common)
1465 (info, name,
1466 h->u.c.section->owner, bfd_link_hash_common, h->u.c.size,
1467 abfd, bfd_link_hash_defined, (bfd_vma) 0)))
1468 return false;
1469 /* Fall through. */
1470 case DEF:
1471 /* Define a symbol. */
1472 h->type = bfd_link_hash_defined;
1473 h->u.def.section = section;
1474 h->u.def.value = value;
1475
1476 /* If we have been asked to, we act like collect2 and
1477 identify all functions that might be global constructors
1478 and destructors and pass them up in a callback. We only
1479 do this for certain object file types, since many object
1480 file types can handle this automatically. */
1481 if (collect && name[0] == '_')
1482 {
1483 const char *s;
1484
1485 /* A constructor or destructor name starts like this:
1486 _+GLOBAL_[_.$][ID][_.$]
1487 where the first [_.$] and the second are the same
1488 character (we accept any character there, in case a
1489 new object file format comes along with even worse
1490 naming restrictions). */
1491
1492 #define CONS_PREFIX "GLOBAL_"
1493 #define CONS_PREFIX_LEN (sizeof CONS_PREFIX - 1)
1494
1495 s = name + 1;
1496 while (*s == '_')
1497 ++s;
1498 if (s[0] == 'G'
1499 && strncmp (s, CONS_PREFIX, CONS_PREFIX_LEN - 1) == 0)
1500 {
1501 char c;
1502
1503 c = s[CONS_PREFIX_LEN + 1];
1504 if ((c == 'I' || c == 'D')
1505 && s[CONS_PREFIX_LEN] == s[CONS_PREFIX_LEN + 2])
1506 {
1507 if (! ((*info->callbacks->constructor)
1508 (info,
1509 c == 'I' ? true : false,
1510 name, abfd, section, value)))
1511 return false;
1512 }
1513 }
1514 }
1515
1516 break;
1517
1518 case COM:
1519 /* We have found a common definition for a symbol. */
1520 if (h->type == bfd_link_hash_new)
1521 bfd_link_add_undef (info->hash, h);
1522 h->type = bfd_link_hash_common;
1523 h->u.c.size = value;
1524 if (h->u.c.size != value)
1525 {
1526 /* The size did not fit in the bitfield. */
1527 bfd_set_error (bfd_error_bad_value);
1528 return false;
1529 }
1530
1531 /* Select a default alignment based on the size. This may
1532 be overridden by the caller. */
1533 {
1534 unsigned int power;
1535
1536 power = bfd_log2 (value);
1537 if (power > 4)
1538 power = 4;
1539 h->u.c.alignment_power = power;
1540 }
1541
1542 /* The section of a common symbol is only used if the common
1543 symbol is actually allocated. It basically provides a
1544 hook for the linker script to decide which output section
1545 the common symbols should be put in. In most cases, the
1546 section of a common symbol will be bfd_com_section_ptr,
1547 the code here will choose a common symbol section named
1548 "COMMON", and the linker script will contain *(COMMON) in
1549 the appropriate place. A few targets use separate common
1550 sections for small symbols, and they require special
1551 handling. */
1552 if (section == bfd_com_section_ptr)
1553 {
1554 h->u.c.section = bfd_make_section_old_way (abfd, "COMMON");
1555 h->u.c.section->flags = SEC_ALLOC;
1556 }
1557 else if (section->owner != abfd)
1558 {
1559 h->u.c.section = bfd_make_section_old_way (abfd, section->name);
1560 h->u.c.section->flags = SEC_ALLOC;
1561 }
1562 else
1563 h->u.c.section = section;
1564 break;
1565
1566 case REF:
1567 /* A reference to a defined symbol. */
1568 if (h->next == NULL && info->hash->undefs_tail != h)
1569 h->next = h;
1570 break;
1571
1572 case BIG:
1573 /* We have found a common definition for a symbol which
1574 already had a common definition. Use the maximum of the
1575 two sizes. */
1576 BFD_ASSERT (h->type == bfd_link_hash_common);
1577 if (! ((*info->callbacks->multiple_common)
1578 (info, name,
1579 h->u.c.section->owner, bfd_link_hash_common, h->u.c.size,
1580 abfd, bfd_link_hash_common, value)))
1581 return false;
1582 if (value > h->u.c.size)
1583 {
1584 unsigned int power;
1585
1586 h->u.c.size = value;
1587
1588 /* Select a default alignment based on the size. This may
1589 be overridden by the caller. */
1590 power = bfd_log2 (value);
1591 if (power > 4)
1592 power = 4;
1593 h->u.c.alignment_power = power;
1594 }
1595 break;
1596
1597 case CREF:
1598 {
1599 bfd *obfd;
1600
1601 /* We have found a common definition for a symbol which
1602 was already defined. FIXME: It would nice if we could
1603 report the BFD which defined an indirect symbol, but we
1604 don't have anywhere to store the information. */
1605 if (h->type == bfd_link_hash_defined)
1606 obfd = h->u.def.section->owner;
1607 else
1608 obfd = NULL;
1609 if (! ((*info->callbacks->multiple_common)
1610 (info, name, obfd, h->type, (bfd_vma) 0,
1611 abfd, bfd_link_hash_common, value)))
1612 return false;
1613 }
1614 break;
1615
1616 case MIND:
1617 /* Multiple indirect symbols. This is OK if they both point
1618 to the same symbol. */
1619 if (strcmp (h->u.i.link->root.string, string) == 0)
1620 break;
1621 /* Fall through. */
1622 case MDEF:
1623 /* Handle a multiple definition. */
1624 {
1625 asection *msec;
1626 bfd_vma mval;
1627
1628 switch (h->type)
1629 {
1630 case bfd_link_hash_defined:
1631 msec = h->u.def.section;
1632 mval = h->u.def.value;
1633 break;
1634 case bfd_link_hash_common:
1635 msec = bfd_com_section_ptr;
1636 mval = h->u.c.size;
1637 break;
1638 case bfd_link_hash_indirect:
1639 msec = bfd_ind_section_ptr;
1640 mval = 0;
1641 break;
1642 default:
1643 abort ();
1644 }
1645
1646 /* Ignore a redefinition of an absolute symbol to the same
1647 value; it's harmless. */
1648 if (h->type == bfd_link_hash_defined
1649 && bfd_is_abs_section (msec)
1650 && bfd_is_abs_section (section)
1651 && value == mval)
1652 break;
1653
1654 if (! ((*info->callbacks->multiple_definition)
1655 (info, name, msec->owner, msec, mval, abfd, section,
1656 value)))
1657 return false;
1658 }
1659 break;
1660
1661 case CIND:
1662 /* Create an indirect symbol from an existing common symbol. */
1663 BFD_ASSERT (h->type == bfd_link_hash_common);
1664 if (! ((*info->callbacks->multiple_common)
1665 (info, name,
1666 h->u.c.section->owner, bfd_link_hash_common, h->u.c.size,
1667 abfd, bfd_link_hash_indirect, (bfd_vma) 0)))
1668 return false;
1669 /* Fall through. */
1670 case IND:
1671 /* Create an indirect symbol. */
1672 {
1673 struct bfd_link_hash_entry *inh;
1674
1675 /* STRING is the name of the symbol we want to indirect
1676 to. */
1677 inh = bfd_link_hash_lookup (info->hash, string, true, copy,
1678 false);
1679 if (inh == (struct bfd_link_hash_entry *) NULL)
1680 return false;
1681 if (inh->type == bfd_link_hash_new)
1682 {
1683 inh->type = bfd_link_hash_undefined;
1684 inh->u.undef.abfd = abfd;
1685 bfd_link_add_undef (info->hash, inh);
1686 }
1687
1688 /* If the indirect symbol has been referenced, we need to
1689 push the reference down to the symbol we are
1690 referencing. */
1691 if (h->type != bfd_link_hash_new)
1692 {
1693 row = UNDEF_ROW;
1694 cycle = true;
1695 }
1696
1697 h->type = bfd_link_hash_indirect;
1698 h->u.i.link = inh;
1699 }
1700 break;
1701
1702 case SET:
1703 /* Add an entry to a set. */
1704 if (! (*info->callbacks->add_to_set) (info, h, BFD_RELOC_CTOR,
1705 abfd, section, value))
1706 return false;
1707 break;
1708
1709 case WARNC:
1710 /* Issue a warning and cycle. */
1711 if (h->u.i.warning != NULL)
1712 {
1713 if (! (*info->callbacks->warning) (info, h->u.i.warning))
1714 return false;
1715 /* Only issue a warning once. */
1716 h->u.i.warning = NULL;
1717 }
1718 /* Fall through. */
1719 case CYCLE:
1720 /* Try again with the referenced symbol. */
1721 h = h->u.i.link;
1722 cycle = true;
1723 break;
1724
1725 case REFC:
1726 /* A reference to an indirect symbol. */
1727 if (h->next == NULL && info->hash->undefs_tail != h)
1728 h->next = h;
1729 h = h->u.i.link;
1730 cycle = true;
1731 break;
1732
1733 case WARN:
1734 /* Issue a warning. */
1735 if (! (*info->callbacks->warning) (info, string))
1736 return false;
1737 break;
1738
1739 case CWARN:
1740 /* Warn if this symbol has been referenced already,
1741 otherwise either add a warning or cycle. A symbol has
1742 been referenced if the next field is not NULL, or it is
1743 the tail of the undefined symbol list. The REF case
1744 above helps to ensure this. */
1745 if (h->next != NULL || info->hash->undefs_tail == h)
1746 {
1747 if (! (*info->callbacks->warning) (info, string))
1748 return false;
1749 break;
1750 }
1751 /* Fall through. */
1752 case MWARN:
1753 /* Make a warning symbol. */
1754 {
1755 struct bfd_link_hash_entry *sub;
1756
1757 /* STRING is the warning to give. */
1758 sub = ((struct bfd_link_hash_entry *)
1759 bfd_hash_allocate (&info->hash->table,
1760 sizeof (struct bfd_link_hash_entry)));
1761 if (!sub)
1762 {
1763 bfd_set_error (bfd_error_no_memory);
1764 return false;
1765 }
1766 *sub = *h;
1767 h->type = bfd_link_hash_warning;
1768 h->u.i.link = sub;
1769 if (! copy)
1770 h->u.i.warning = string;
1771 else
1772 {
1773 char *w;
1774
1775 w = bfd_hash_allocate (&info->hash->table,
1776 strlen (string) + 1);
1777 strcpy (w, string);
1778 h->u.i.warning = w;
1779 }
1780 }
1781 break;
1782 }
1783 }
1784 while (cycle);
1785
1786 return true;
1787 }
1788 \f
1789 /* Generic final link routine. */
1790
1791 boolean
1792 _bfd_generic_final_link (abfd, info)
1793 bfd *abfd;
1794 struct bfd_link_info *info;
1795 {
1796 bfd *sub;
1797 asection *o;
1798 struct bfd_link_order *p;
1799 size_t outsymalloc;
1800 struct generic_write_global_symbol_info wginfo;
1801
1802 abfd->outsymbols = (asymbol **) NULL;
1803 abfd->symcount = 0;
1804 outsymalloc = 0;
1805
1806 /* Build the output symbol table. */
1807 for (sub = info->input_bfds; sub != (bfd *) NULL; sub = sub->link_next)
1808 if (! _bfd_generic_link_output_symbols (abfd, sub, info, &outsymalloc))
1809 return false;
1810
1811 /* Accumulate the global symbols. */
1812 wginfo.info = info;
1813 wginfo.output_bfd = abfd;
1814 wginfo.psymalloc = &outsymalloc;
1815 _bfd_generic_link_hash_traverse (_bfd_generic_hash_table (info),
1816 _bfd_generic_link_write_global_symbol,
1817 (PTR) &wginfo);
1818
1819 if (info->relocateable)
1820 {
1821 /* Allocate space for the output relocs for each section. */
1822 for (o = abfd->sections;
1823 o != (asection *) NULL;
1824 o = o->next)
1825 {
1826 o->reloc_count = 0;
1827 for (p = o->link_order_head;
1828 p != (struct bfd_link_order *) NULL;
1829 p = p->next)
1830 {
1831 if (p->type == bfd_section_reloc_link_order
1832 || p->type == bfd_symbol_reloc_link_order)
1833 ++o->reloc_count;
1834 else if (p->type == bfd_indirect_link_order)
1835 {
1836 asection *input_section;
1837 bfd *input_bfd;
1838 long relsize;
1839 arelent **relocs;
1840 asymbol **symbols;
1841 long reloc_count;
1842
1843 input_section = p->u.indirect.section;
1844 input_bfd = input_section->owner;
1845 relsize = bfd_get_reloc_upper_bound (input_bfd,
1846 input_section);
1847 if (relsize < 0)
1848 return false;
1849 relocs = (arelent **) malloc ((size_t) relsize);
1850 if (!relocs && relsize != 0)
1851 {
1852 bfd_set_error (bfd_error_no_memory);
1853 return false;
1854 }
1855 symbols = _bfd_generic_link_get_symbols (input_bfd);
1856 reloc_count = bfd_canonicalize_reloc (input_bfd,
1857 input_section,
1858 relocs,
1859 symbols);
1860 if (reloc_count < 0)
1861 return false;
1862 BFD_ASSERT (reloc_count == input_section->reloc_count);
1863 o->reloc_count += reloc_count;
1864 free (relocs);
1865 }
1866 }
1867 if (o->reloc_count > 0)
1868 {
1869 o->orelocation = ((arelent **)
1870 bfd_alloc (abfd,
1871 (o->reloc_count
1872 * sizeof (arelent *))));
1873 if (!o->orelocation)
1874 {
1875 bfd_set_error (bfd_error_no_memory);
1876 return false;
1877 }
1878 o->flags |= SEC_RELOC;
1879 /* Reset the count so that it can be used as an index
1880 when putting in the output relocs. */
1881 o->reloc_count = 0;
1882 }
1883 }
1884 }
1885
1886 /* Handle all the link order information for the sections. */
1887 for (o = abfd->sections;
1888 o != (asection *) NULL;
1889 o = o->next)
1890 {
1891 for (p = o->link_order_head;
1892 p != (struct bfd_link_order *) NULL;
1893 p = p->next)
1894 {
1895 switch (p->type)
1896 {
1897 case bfd_section_reloc_link_order:
1898 case bfd_symbol_reloc_link_order:
1899 if (! _bfd_generic_reloc_link_order (abfd, info, o, p))
1900 return false;
1901 break;
1902 case bfd_indirect_link_order:
1903 if (! default_indirect_link_order (abfd, info, o, p, true))
1904 return false;
1905 break;
1906 default:
1907 if (! _bfd_default_link_order (abfd, info, o, p))
1908 return false;
1909 break;
1910 }
1911 }
1912 }
1913
1914 return true;
1915 }
1916
1917 /* Add an output symbol to the output BFD. */
1918
1919 static boolean
1920 generic_add_output_symbol (output_bfd, psymalloc, sym)
1921 bfd *output_bfd;
1922 size_t *psymalloc;
1923 asymbol *sym;
1924 {
1925 if (output_bfd->symcount >= *psymalloc)
1926 {
1927 asymbol **newsyms;
1928
1929 if (*psymalloc == 0)
1930 *psymalloc = 124;
1931 else
1932 *psymalloc *= 2;
1933 if (output_bfd->outsymbols == (asymbol **) NULL)
1934 newsyms = (asymbol **) malloc (*psymalloc * sizeof (asymbol *));
1935 else
1936 newsyms = (asymbol **) realloc (output_bfd->outsymbols,
1937 *psymalloc * sizeof (asymbol *));
1938 if (newsyms == (asymbol **) NULL)
1939 {
1940 bfd_set_error (bfd_error_no_memory);
1941 return false;
1942 }
1943 output_bfd->outsymbols = newsyms;
1944 }
1945
1946 output_bfd->outsymbols[output_bfd->symcount] = sym;
1947 ++output_bfd->symcount;
1948
1949 return true;
1950 }
1951
1952 /* Handle the symbols for an input BFD. */
1953
1954 boolean
1955 _bfd_generic_link_output_symbols (output_bfd, input_bfd, info, psymalloc)
1956 bfd *output_bfd;
1957 bfd *input_bfd;
1958 struct bfd_link_info *info;
1959 size_t *psymalloc;
1960 {
1961 asymbol **sym_ptr;
1962 asymbol **sym_end;
1963
1964 if (! generic_link_read_symbols (input_bfd))
1965 return false;
1966
1967 /* Create a filename symbol if we are supposed to. */
1968 if (info->create_object_symbols_section != (asection *) NULL)
1969 {
1970 asection *sec;
1971
1972 for (sec = input_bfd->sections;
1973 sec != (asection *) NULL;
1974 sec = sec->next)
1975 {
1976 if (sec->output_section == info->create_object_symbols_section)
1977 {
1978 asymbol *newsym;
1979
1980 newsym = bfd_make_empty_symbol (input_bfd);
1981 if (!newsym)
1982 return false;
1983 newsym->name = input_bfd->filename;
1984 newsym->value = 0;
1985 newsym->flags = BSF_LOCAL | BSF_FILE;
1986 newsym->section = sec;
1987
1988 if (! generic_add_output_symbol (output_bfd, psymalloc,
1989 newsym))
1990 return false;
1991
1992 break;
1993 }
1994 }
1995 }
1996
1997 /* Adjust the values of the globally visible symbols, and write out
1998 local symbols. */
1999 sym_ptr = _bfd_generic_link_get_symbols (input_bfd);
2000 sym_end = sym_ptr + _bfd_generic_link_get_symcount (input_bfd);
2001 for (; sym_ptr < sym_end; sym_ptr++)
2002 {
2003 asymbol *sym;
2004 struct generic_link_hash_entry *h;
2005 boolean output;
2006
2007 h = (struct generic_link_hash_entry *) NULL;
2008 sym = *sym_ptr;
2009 if ((sym->flags & (BSF_INDIRECT
2010 | BSF_WARNING
2011 | BSF_GLOBAL
2012 | BSF_CONSTRUCTOR
2013 | BSF_WEAK)) != 0
2014 || bfd_is_und_section (bfd_get_section (sym))
2015 || bfd_is_com_section (bfd_get_section (sym))
2016 || bfd_is_ind_section (bfd_get_section (sym)))
2017 {
2018 h = _bfd_generic_link_hash_lookup (_bfd_generic_hash_table (info),
2019 bfd_asymbol_name (sym),
2020 false, false, true);
2021 if (h != (struct generic_link_hash_entry *) NULL)
2022 {
2023 /* Force all references to this symbol to point to
2024 the same area in memory. It is possible that
2025 this routine will be called with a hash table
2026 other than a generic hash table, so we double
2027 check that. */
2028 if (info->hash->creator == input_bfd->xvec)
2029 {
2030 if (h->sym != (asymbol *) NULL)
2031 *sym_ptr = sym = h->sym;
2032 }
2033
2034 switch (h->root.type)
2035 {
2036 default:
2037 case bfd_link_hash_new:
2038 abort ();
2039 case bfd_link_hash_undefined:
2040 case bfd_link_hash_weak:
2041 break;
2042 case bfd_link_hash_defined:
2043 sym->value = h->root.u.def.value;
2044 sym->section = h->root.u.def.section;
2045 sym->flags |= BSF_GLOBAL;
2046 break;
2047 case bfd_link_hash_common:
2048 sym->value = h->root.u.c.size;
2049 sym->flags |= BSF_GLOBAL;
2050 if (! bfd_is_com_section (sym->section))
2051 {
2052 BFD_ASSERT (bfd_is_und_section (sym->section));
2053 sym->section = bfd_com_section_ptr;
2054 }
2055 /* We do not set the section of the symbol to
2056 h->root.u.c.section. That value was saved so
2057 that we would know where to allocate the symbol
2058 if it was defined. In this case the type is
2059 still bfd_link_hash_common, so we did not define
2060 it, so we do not want to use that section. */
2061 break;
2062 }
2063 }
2064 }
2065
2066 /* This switch is straight from the old code in
2067 write_file_locals in ldsym.c. */
2068 if (info->strip == strip_some
2069 && (bfd_hash_lookup (info->keep_hash, bfd_asymbol_name (sym),
2070 false, false)
2071 == (struct bfd_hash_entry *) NULL))
2072 output = false;
2073 else if ((sym->flags & (BSF_GLOBAL | BSF_WEAK)) != 0)
2074 {
2075 /* If this symbol is marked as occurring now, rather
2076 than at the end, output it now. This is used for
2077 COFF C_EXT FCN symbols. FIXME: There must be a
2078 better way. */
2079 if (bfd_asymbol_bfd (sym) == input_bfd
2080 && (sym->flags & BSF_NOT_AT_END) != 0)
2081 output = true;
2082 else
2083 output = false;
2084 }
2085 else if (bfd_is_ind_section (sym->section))
2086 output = false;
2087 else if ((sym->flags & BSF_DEBUGGING) != 0)
2088 {
2089 if (info->strip == strip_none)
2090 output = true;
2091 else
2092 output = false;
2093 }
2094 else if (bfd_is_und_section (sym->section)
2095 || bfd_is_com_section (sym->section))
2096 output = false;
2097 else if ((sym->flags & BSF_LOCAL) != 0)
2098 {
2099 if ((sym->flags & BSF_WARNING) != 0)
2100 output = false;
2101 else
2102 {
2103 switch (info->discard)
2104 {
2105 default:
2106 case discard_all:
2107 output = false;
2108 break;
2109 case discard_l:
2110 if (bfd_asymbol_name (sym)[0] == info->lprefix[0]
2111 && (info->lprefix_len == 1
2112 || strncmp (bfd_asymbol_name (sym), info->lprefix,
2113 info->lprefix_len) == 0))
2114 output = false;
2115 else
2116 output = true;
2117 break;
2118 case discard_none:
2119 output = true;
2120 break;
2121 }
2122 }
2123 }
2124 else if ((sym->flags & BSF_CONSTRUCTOR))
2125 {
2126 if (info->strip != strip_all)
2127 output = true;
2128 else
2129 output = false;
2130 }
2131 else
2132 abort ();
2133
2134 if (output)
2135 {
2136 if (! generic_add_output_symbol (output_bfd, psymalloc, sym))
2137 return false;
2138 if (h != (struct generic_link_hash_entry *) NULL)
2139 h->written = true;
2140 }
2141 }
2142
2143 return true;
2144 }
2145
2146 /* Set the section and value of a generic BFD symbol based on a linker
2147 hash table entry. */
2148
2149 static void
2150 set_symbol_from_hash (sym, h)
2151 asymbol *sym;
2152 struct bfd_link_hash_entry *h;
2153 {
2154 switch (h->type)
2155 {
2156 default:
2157 case bfd_link_hash_new:
2158 abort ();
2159 case bfd_link_hash_undefined:
2160 sym->section = bfd_und_section_ptr;
2161 sym->value = 0;
2162 break;
2163 case bfd_link_hash_weak:
2164 sym->section = bfd_und_section_ptr;
2165 sym->value = 0;
2166 sym->flags |= BSF_WEAK;
2167 break;
2168 case bfd_link_hash_defined:
2169 sym->section = h->u.def.section;
2170 sym->value = h->u.def.value;
2171 break;
2172 case bfd_link_hash_common:
2173 sym->value = h->u.c.size;
2174 if (sym->section == NULL)
2175 sym->section = bfd_com_section_ptr;
2176 else if (! bfd_is_com_section (sym->section))
2177 {
2178 BFD_ASSERT (bfd_is_und_section (sym->section));
2179 sym->section = bfd_com_section_ptr;
2180 }
2181 /* Do not set the section; see _bfd_generic_link_output_symbols. */
2182 break;
2183 case bfd_link_hash_indirect:
2184 case bfd_link_hash_warning:
2185 /* FIXME: What should we do here? */
2186 break;
2187 }
2188 }
2189
2190 /* Write out a global symbol, if it hasn't already been written out.
2191 This is called for each symbol in the hash table. */
2192
2193 boolean
2194 _bfd_generic_link_write_global_symbol (h, data)
2195 struct generic_link_hash_entry *h;
2196 PTR data;
2197 {
2198 struct generic_write_global_symbol_info *wginfo =
2199 (struct generic_write_global_symbol_info *) data;
2200 asymbol *sym;
2201
2202 if (h->written)
2203 return true;
2204
2205 h->written = true;
2206
2207 if (wginfo->info->strip == strip_all
2208 || (wginfo->info->strip == strip_some
2209 && bfd_hash_lookup (wginfo->info->keep_hash, h->root.root.string,
2210 false, false) == NULL))
2211 return true;
2212
2213 if (h->sym != (asymbol *) NULL)
2214 {
2215 sym = h->sym;
2216 BFD_ASSERT (strcmp (bfd_asymbol_name (sym), h->root.root.string) == 0);
2217 }
2218 else
2219 {
2220 sym = bfd_make_empty_symbol (wginfo->output_bfd);
2221 if (!sym)
2222 return false;
2223 sym->name = h->root.root.string;
2224 sym->flags = 0;
2225 }
2226
2227 set_symbol_from_hash (sym, &h->root);
2228
2229 sym->flags |= BSF_GLOBAL;
2230
2231 if (! generic_add_output_symbol (wginfo->output_bfd, wginfo->psymalloc,
2232 sym))
2233 {
2234 /* FIXME: No way to return failure. */
2235 abort ();
2236 }
2237
2238 return true;
2239 }
2240
2241 /* Create a relocation. */
2242
2243 boolean
2244 _bfd_generic_reloc_link_order (abfd, info, sec, link_order)
2245 bfd *abfd;
2246 struct bfd_link_info *info;
2247 asection *sec;
2248 struct bfd_link_order *link_order;
2249 {
2250 arelent *r;
2251
2252 if (! info->relocateable)
2253 abort ();
2254 if (sec->orelocation == (arelent **) NULL)
2255 abort ();
2256
2257 r = (arelent *) bfd_alloc (abfd, sizeof (arelent));
2258 if (r == (arelent *) NULL)
2259 {
2260 bfd_set_error (bfd_error_no_memory);
2261 return false;
2262 }
2263
2264 r->address = link_order->offset;
2265 r->howto = bfd_reloc_type_lookup (abfd, link_order->u.reloc.p->reloc);
2266 if (r->howto == (const reloc_howto_type *) NULL)
2267 {
2268 bfd_set_error (bfd_error_bad_value);
2269 return false;
2270 }
2271
2272 /* Get the symbol to use for the relocation. */
2273 if (link_order->type == bfd_section_reloc_link_order)
2274 r->sym_ptr_ptr = link_order->u.reloc.p->u.section->symbol_ptr_ptr;
2275 else
2276 {
2277 struct generic_link_hash_entry *h;
2278
2279 h = _bfd_generic_link_hash_lookup (_bfd_generic_hash_table (info),
2280 link_order->u.reloc.p->u.name,
2281 false, false, true);
2282 if (h == (struct generic_link_hash_entry *) NULL
2283 || ! h->written)
2284 {
2285 if (! ((*info->callbacks->unattached_reloc)
2286 (info, link_order->u.reloc.p->u.name,
2287 (bfd *) NULL, (asection *) NULL, (bfd_vma) 0)))
2288 return false;
2289 bfd_set_error (bfd_error_bad_value);
2290 return false;
2291 }
2292 r->sym_ptr_ptr = &h->sym;
2293 }
2294
2295 /* If this is an inplace reloc, write the addend to the object file.
2296 Otherwise, store it in the reloc addend. */
2297 if (! r->howto->partial_inplace)
2298 r->addend = link_order->u.reloc.p->addend;
2299 else
2300 {
2301 bfd_size_type size;
2302 bfd_reloc_status_type rstat;
2303 bfd_byte *buf;
2304 boolean ok;
2305
2306 size = bfd_get_reloc_size (r->howto);
2307 buf = (bfd_byte *) bfd_zmalloc (size);
2308 if (buf == (bfd_byte *) NULL)
2309 {
2310 bfd_set_error (bfd_error_no_memory);
2311 return false;
2312 }
2313 rstat = _bfd_relocate_contents (r->howto, abfd,
2314 link_order->u.reloc.p->addend, buf);
2315 switch (rstat)
2316 {
2317 case bfd_reloc_ok:
2318 break;
2319 default:
2320 case bfd_reloc_outofrange:
2321 abort ();
2322 case bfd_reloc_overflow:
2323 if (! ((*info->callbacks->reloc_overflow)
2324 (info,
2325 (link_order->type == bfd_section_reloc_link_order
2326 ? bfd_section_name (abfd, link_order->u.reloc.p->u.section)
2327 : link_order->u.reloc.p->u.name),
2328 r->howto->name, link_order->u.reloc.p->addend,
2329 (bfd *) NULL, (asection *) NULL, (bfd_vma) 0)))
2330 {
2331 free (buf);
2332 return false;
2333 }
2334 break;
2335 }
2336 ok = bfd_set_section_contents (abfd, sec, (PTR) buf,
2337 (file_ptr) link_order->offset, size);
2338 free (buf);
2339 if (! ok)
2340 return false;
2341
2342 r->addend = 0;
2343 }
2344
2345 sec->orelocation[sec->reloc_count] = r;
2346 ++sec->reloc_count;
2347
2348 return true;
2349 }
2350 \f
2351 /* Allocate a new link_order for a section. */
2352
2353 struct bfd_link_order *
2354 bfd_new_link_order (abfd, section)
2355 bfd *abfd;
2356 asection *section;
2357 {
2358 struct bfd_link_order *new;
2359
2360 new = ((struct bfd_link_order *)
2361 bfd_alloc_by_size_t (abfd, sizeof (struct bfd_link_order)));
2362 if (!new)
2363 {
2364 bfd_set_error (bfd_error_no_memory);
2365 return NULL;
2366 }
2367
2368 new->type = bfd_undefined_link_order;
2369 new->offset = 0;
2370 new->size = 0;
2371 new->next = (struct bfd_link_order *) NULL;
2372
2373 if (section->link_order_tail != (struct bfd_link_order *) NULL)
2374 section->link_order_tail->next = new;
2375 else
2376 section->link_order_head = new;
2377 section->link_order_tail = new;
2378
2379 return new;
2380 }
2381
2382 /* Default link order processing routine. Note that we can not handle
2383 the reloc_link_order types here, since they depend upon the details
2384 of how the particular backends generates relocs. */
2385
2386 boolean
2387 _bfd_default_link_order (abfd, info, sec, link_order)
2388 bfd *abfd;
2389 struct bfd_link_info *info;
2390 asection *sec;
2391 struct bfd_link_order *link_order;
2392 {
2393 switch (link_order->type)
2394 {
2395 case bfd_undefined_link_order:
2396 case bfd_section_reloc_link_order:
2397 case bfd_symbol_reloc_link_order:
2398 default:
2399 abort ();
2400 case bfd_indirect_link_order:
2401 return default_indirect_link_order (abfd, info, sec, link_order,
2402 false);
2403 case bfd_fill_link_order:
2404 return default_fill_link_order (abfd, info, sec, link_order);
2405 case bfd_data_link_order:
2406 return bfd_set_section_contents (abfd, sec,
2407 (PTR) link_order->u.data.contents,
2408 (file_ptr) link_order->offset,
2409 link_order->size);
2410 }
2411 }
2412
2413 /* Default routine to handle a bfd_fill_link_order. */
2414
2415 /*ARGSUSED*/
2416 static boolean
2417 default_fill_link_order (abfd, info, sec, link_order)
2418 bfd *abfd;
2419 struct bfd_link_info *info;
2420 asection *sec;
2421 struct bfd_link_order *link_order;
2422 {
2423 size_t size;
2424 char *space;
2425 size_t i;
2426 int fill;
2427 boolean result;
2428
2429 BFD_ASSERT ((sec->flags & SEC_HAS_CONTENTS) != 0);
2430
2431 size = (size_t) link_order->size;
2432 space = (char *) malloc (size);
2433 if (space == NULL && size != 0)
2434 {
2435 bfd_set_error (bfd_error_no_memory);
2436 return false;
2437 }
2438
2439 fill = link_order->u.fill.value;
2440 for (i = 0; i < size; i += 2)
2441 space[i] = fill >> 8;
2442 for (i = 1; i < size; i += 2)
2443 space[i] = fill;
2444 result = bfd_set_section_contents (abfd, sec, space,
2445 (file_ptr) link_order->offset,
2446 link_order->size);
2447 free (space);
2448 return result;
2449 }
2450
2451 /* Default routine to handle a bfd_indirect_link_order. */
2452
2453 static boolean
2454 default_indirect_link_order (output_bfd, info, output_section, link_order,
2455 generic_linker)
2456 bfd *output_bfd;
2457 struct bfd_link_info *info;
2458 asection *output_section;
2459 struct bfd_link_order *link_order;
2460 boolean generic_linker;
2461 {
2462 asection *input_section;
2463 bfd *input_bfd;
2464 bfd_byte *contents = NULL;
2465 bfd_byte *new_contents;
2466
2467 BFD_ASSERT ((output_section->flags & SEC_HAS_CONTENTS) != 0);
2468
2469 if (link_order->size == 0)
2470 return true;
2471
2472 input_section = link_order->u.indirect.section;
2473 input_bfd = input_section->owner;
2474
2475 BFD_ASSERT (input_section->output_section == output_section);
2476 BFD_ASSERT (input_section->output_offset == link_order->offset);
2477 BFD_ASSERT (input_section->_cooked_size == link_order->size);
2478
2479 if (info->relocateable
2480 && input_section->reloc_count > 0
2481 && output_section->orelocation == (arelent **) NULL)
2482 {
2483 /* Space has not been allocated for the output relocations.
2484 This can happen when we are called by a specific backend
2485 because somebody is attempting to link together different
2486 types of object files. Handling this case correctly is
2487 difficult, and sometimes impossible. */
2488 abort ();
2489 }
2490
2491 if (! generic_linker)
2492 {
2493 asymbol **sympp;
2494 asymbol **symppend;
2495
2496 /* Get the canonical symbols. The generic linker will always
2497 have retrieved them by this point, but we are being called by
2498 a specific linker, presumably because we are linking
2499 different types of object files together. */
2500 if (! generic_link_read_symbols (input_bfd))
2501 return false;
2502
2503 /* Since we have been called by a specific linker, rather than
2504 the generic linker, the values of the symbols will not be
2505 right. They will be the values as seen in the input file,
2506 not the values of the final link. We need to fix them up
2507 before we can relocate the section. */
2508 sympp = _bfd_generic_link_get_symbols (input_bfd);
2509 symppend = sympp + _bfd_generic_link_get_symcount (input_bfd);
2510 for (; sympp < symppend; sympp++)
2511 {
2512 asymbol *sym;
2513 struct bfd_link_hash_entry *h;
2514
2515 sym = *sympp;
2516
2517 if ((sym->flags & (BSF_INDIRECT
2518 | BSF_WARNING
2519 | BSF_GLOBAL
2520 | BSF_CONSTRUCTOR
2521 | BSF_WEAK)) != 0
2522 || bfd_is_und_section (bfd_get_section (sym))
2523 || bfd_is_com_section (bfd_get_section (sym))
2524 || bfd_is_ind_section (bfd_get_section (sym)))
2525 {
2526 /* sym->udata may have been set by
2527 generic_link_add_symbol_list. */
2528 if (sym->udata.p != NULL)
2529 h = (struct bfd_link_hash_entry *) sym->udata.p;
2530 else
2531 h = bfd_link_hash_lookup (info->hash,
2532 bfd_asymbol_name (sym),
2533 false, false, true);
2534 if (h != NULL)
2535 set_symbol_from_hash (sym, h);
2536 }
2537 }
2538 }
2539
2540 /* Get and relocate the section contents. */
2541 contents = (bfd_byte *) malloc (bfd_section_size (input_bfd, input_section));
2542 if (contents == NULL && bfd_section_size (input_bfd, input_section) != 0)
2543 {
2544 bfd_set_error (bfd_error_no_memory);
2545 goto error_return;
2546 }
2547 new_contents = (bfd_get_relocated_section_contents
2548 (output_bfd, info, link_order, contents, info->relocateable,
2549 _bfd_generic_link_get_symbols (input_bfd)));
2550 if (!new_contents)
2551 goto error_return;
2552
2553 /* Output the section contents. */
2554 if (! bfd_set_section_contents (output_bfd, output_section,
2555 (PTR) new_contents,
2556 link_order->offset, link_order->size))
2557 goto error_return;
2558
2559 if (contents != NULL)
2560 free (contents);
2561 return true;
2562
2563 error_return:
2564 if (contents != NULL)
2565 free (contents);
2566 return false;
2567 }
2568
2569 /* A little routine to count the number of relocs in a link_order
2570 list. */
2571
2572 unsigned int
2573 _bfd_count_link_order_relocs (link_order)
2574 struct bfd_link_order *link_order;
2575 {
2576 register unsigned int c;
2577 register struct bfd_link_order *l;
2578
2579 c = 0;
2580 for (l = link_order; l != (struct bfd_link_order *) NULL; l = l->next)
2581 {
2582 if (l->type == bfd_section_reloc_link_order
2583 || l->type == bfd_symbol_reloc_link_order)
2584 ++c;
2585 }
2586
2587 return c;
2588 }