comment on v9 stuff
[deliverable/binutils-gdb.git] / bfd / linker.c
1 /* linker.c -- BFD linker routines
2 Copyright (C) 1993, 94 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>> for an undefined
196 symbol or <<bfd_com_section>> 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 boolean generic_add_output_symbol
431 PARAMS ((bfd *, size_t *psymalloc, asymbol *));
432 static boolean default_fill_link_order
433 PARAMS ((bfd *, struct bfd_link_info *, asection *,
434 struct bfd_link_order *));
435 static boolean default_indirect_link_order
436 PARAMS ((bfd *, struct bfd_link_info *, asection *,
437 struct bfd_link_order *));
438
439 /* The link hash table structure is defined in bfdlink.h. It provides
440 a base hash table which the backend specific hash tables are built
441 upon. */
442
443 /* Routine to create an entry in the link hash table. */
444
445 struct bfd_hash_entry *
446 _bfd_link_hash_newfunc (entry, table, string)
447 struct bfd_hash_entry *entry;
448 struct bfd_hash_table *table;
449 const char *string;
450 {
451 struct bfd_link_hash_entry *ret = (struct bfd_link_hash_entry *) entry;
452
453 /* Allocate the structure if it has not already been allocated by a
454 subclass. */
455 if (ret == (struct bfd_link_hash_entry *) NULL)
456 ret = ((struct bfd_link_hash_entry *)
457 bfd_hash_allocate (table, sizeof (struct bfd_link_hash_entry)));
458 if (ret == (struct bfd_link_hash_entry *) NULL)
459 {
460 bfd_set_error (bfd_error_no_memory);
461 return NULL;
462 }
463
464 /* Call the allocation method of the superclass. */
465 ret = ((struct bfd_link_hash_entry *)
466 bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));
467
468 if (ret)
469 {
470 /* Initialize the local fields. */
471 ret->type = bfd_link_hash_new;
472 ret->next = NULL;
473 }
474
475 return (struct bfd_hash_entry *) ret;
476 }
477
478 /* Initialize a link hash table. The BFD argument is the one
479 responsible for creating this table. */
480
481 boolean
482 _bfd_link_hash_table_init (table, abfd, newfunc)
483 struct bfd_link_hash_table *table;
484 bfd *abfd;
485 struct bfd_hash_entry *(*newfunc) PARAMS ((struct bfd_hash_entry *,
486 struct bfd_hash_table *,
487 const char *));
488 {
489 table->creator = abfd->xvec;
490 table->undefs = NULL;
491 table->undefs_tail = NULL;
492 return bfd_hash_table_init (&table->table, newfunc);
493 }
494
495 /* Look up a symbol in a link hash table. If follow is true, we
496 follow bfd_link_hash_indirect and bfd_link_hash_warning links to
497 the real symbol. */
498
499 struct bfd_link_hash_entry *
500 bfd_link_hash_lookup (table, string, create, copy, follow)
501 struct bfd_link_hash_table *table;
502 const char *string;
503 boolean create;
504 boolean copy;
505 boolean follow;
506 {
507 struct bfd_link_hash_entry *ret;
508
509 ret = ((struct bfd_link_hash_entry *)
510 bfd_hash_lookup (&table->table, string, create, copy));
511
512 if (follow && ret != (struct bfd_link_hash_entry *) NULL)
513 {
514 while (ret->type == bfd_link_hash_indirect
515 || ret->type == bfd_link_hash_warning)
516 ret = ret->u.i.link;
517 }
518
519 return ret;
520 }
521
522 /* Traverse a generic link hash table. The only reason this is not a
523 macro is to do better type checking. This code presumes that an
524 argument passed as a struct bfd_hash_entry * may be caught as a
525 struct bfd_link_hash_entry * with no explicit cast required on the
526 call. */
527
528 void
529 bfd_link_hash_traverse (table, func, info)
530 struct bfd_link_hash_table *table;
531 boolean (*func) PARAMS ((struct bfd_link_hash_entry *, PTR));
532 PTR info;
533 {
534 bfd_hash_traverse (&table->table,
535 ((boolean (*) PARAMS ((struct bfd_hash_entry *, PTR)))
536 func),
537 info);
538 }
539
540 /* Add a symbol to the linker hash table undefs list. */
541
542 INLINE void
543 bfd_link_add_undef (table, h)
544 struct bfd_link_hash_table *table;
545 struct bfd_link_hash_entry *h;
546 {
547 BFD_ASSERT (h->next == NULL);
548 if (table->undefs_tail != (struct bfd_link_hash_entry *) NULL)
549 table->undefs_tail->next = h;
550 if (table->undefs == (struct bfd_link_hash_entry *) NULL)
551 table->undefs = h;
552 table->undefs_tail = h;
553 }
554 \f
555 /* Routine to create an entry in an generic link hash table. */
556
557 static struct bfd_hash_entry *
558 generic_link_hash_newfunc (entry, table, string)
559 struct bfd_hash_entry *entry;
560 struct bfd_hash_table *table;
561 const char *string;
562 {
563 struct generic_link_hash_entry *ret =
564 (struct generic_link_hash_entry *) entry;
565
566 /* Allocate the structure if it has not already been allocated by a
567 subclass. */
568 if (ret == (struct generic_link_hash_entry *) NULL)
569 ret = ((struct generic_link_hash_entry *)
570 bfd_hash_allocate (table, sizeof (struct generic_link_hash_entry)));
571 if (ret == (struct generic_link_hash_entry *) NULL)
572 {
573 bfd_set_error (bfd_error_no_memory);
574 return NULL;
575 }
576
577 /* Call the allocation method of the superclass. */
578 ret = ((struct generic_link_hash_entry *)
579 _bfd_link_hash_newfunc ((struct bfd_hash_entry *) ret,
580 table, string));
581
582 if (ret)
583 {
584 /* Set local fields. */
585 ret->written = false;
586 ret->sym = NULL;
587 }
588
589 return (struct bfd_hash_entry *) ret;
590 }
591
592 /* Create an generic link hash table. */
593
594 struct bfd_link_hash_table *
595 _bfd_generic_link_hash_table_create (abfd)
596 bfd *abfd;
597 {
598 struct generic_link_hash_table *ret;
599
600 ret = ((struct generic_link_hash_table *)
601 malloc (sizeof (struct generic_link_hash_table)));
602 if (!ret)
603 {
604 bfd_set_error (bfd_error_no_memory);
605 return (struct bfd_link_hash_table *) NULL;
606 }
607 if (! _bfd_link_hash_table_init (&ret->root, abfd,
608 generic_link_hash_newfunc))
609 {
610 free (ret);
611 return (struct bfd_link_hash_table *) NULL;
612 }
613 return &ret->root;
614 }
615
616 /* Grab the symbols for an object file when doing a generic link. We
617 store the symbols in the outsymbols field. We need to keep them
618 around for the entire link to ensure that we only read them once.
619 If we read them multiple times, we might wind up with relocs and
620 the hash table pointing to different instances of the symbol
621 structure. */
622
623 static boolean
624 generic_link_read_symbols (abfd)
625 bfd *abfd;
626 {
627 if (abfd->outsymbols == (asymbol **) NULL)
628 {
629 long symsize;
630 long symcount;
631
632 symsize = bfd_get_symtab_upper_bound (abfd);
633 if (symsize < 0)
634 return false;
635 abfd->outsymbols = (asymbol **) bfd_alloc (abfd, symsize);
636 if (abfd->outsymbols == NULL && symsize != 0)
637 {
638 bfd_set_error (bfd_error_no_memory);
639 return false;
640 }
641 symcount = bfd_canonicalize_symtab (abfd, abfd->outsymbols);
642 if (symcount < 0)
643 return false;
644 abfd->symcount = symcount;
645 }
646
647 return true;
648 }
649 \f
650 /* Generic function to add symbols to from an object file to the
651 global hash table. This version does not automatically collect
652 constructors by name. */
653
654 boolean
655 _bfd_generic_link_add_symbols (abfd, info)
656 bfd *abfd;
657 struct bfd_link_info *info;
658 {
659 return generic_link_add_symbols (abfd, info, false);
660 }
661
662 /* Generic function to add symbols from an object file to the global
663 hash table. This version automatically collects constructors by
664 name, as the collect2 program does. It should be used for any
665 target which does not provide some other mechanism for setting up
666 constructors and destructors; these are approximately those targets
667 for which gcc uses collect2 and do not support stabs. */
668
669 boolean
670 _bfd_generic_link_add_symbols_collect (abfd, info)
671 bfd *abfd;
672 struct bfd_link_info *info;
673 {
674 return generic_link_add_symbols (abfd, info, true);
675 }
676
677 /* Add symbols from an object file to the global hash table. */
678
679 static boolean
680 generic_link_add_symbols (abfd, info, collect)
681 bfd *abfd;
682 struct bfd_link_info *info;
683 boolean collect;
684 {
685 boolean ret;
686
687 switch (bfd_get_format (abfd))
688 {
689 case bfd_object:
690 ret = generic_link_add_object_symbols (abfd, info, collect);
691 break;
692 case bfd_archive:
693 ret = (_bfd_generic_link_add_archive_symbols
694 (abfd, info,
695 (collect
696 ? generic_link_check_archive_element_collect
697 : generic_link_check_archive_element_no_collect)));
698 break;
699 default:
700 bfd_set_error (bfd_error_wrong_format);
701 ret = false;
702 }
703
704 return ret;
705 }
706
707 /* Add symbols from an object file to the global hash table. */
708
709 static boolean
710 generic_link_add_object_symbols (abfd, info, collect)
711 bfd *abfd;
712 struct bfd_link_info *info;
713 boolean collect;
714 {
715 if (! generic_link_read_symbols (abfd))
716 return false;
717 return generic_link_add_symbol_list (abfd, info,
718 _bfd_generic_link_get_symcount (abfd),
719 _bfd_generic_link_get_symbols (abfd),
720 collect);
721 }
722 \f
723 /* We build a hash table of all symbols defined in an archive. */
724
725 /* An archive symbol may be defined by multiple archive elements.
726 This linked list is used to hold the elements. */
727
728 struct archive_list
729 {
730 struct archive_list *next;
731 int indx;
732 };
733
734 /* An entry in an archive hash table. */
735
736 struct archive_hash_entry
737 {
738 struct bfd_hash_entry root;
739 /* Where the symbol is defined. */
740 struct archive_list *defs;
741 };
742
743 /* An archive hash table itself. */
744
745 struct archive_hash_table
746 {
747 struct bfd_hash_table table;
748 };
749
750 static struct bfd_hash_entry *archive_hash_newfunc
751 PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *));
752 static boolean archive_hash_table_init
753 PARAMS ((struct archive_hash_table *,
754 struct bfd_hash_entry *(*) (struct bfd_hash_entry *,
755 struct bfd_hash_table *,
756 const char *)));
757
758 /* Create a new entry for an archive hash table. */
759
760 static struct bfd_hash_entry *
761 archive_hash_newfunc (entry, table, string)
762 struct bfd_hash_entry *entry;
763 struct bfd_hash_table *table;
764 const char *string;
765 {
766 struct archive_hash_entry *ret = (struct archive_hash_entry *) entry;
767
768 /* Allocate the structure if it has not already been allocated by a
769 subclass. */
770 if (ret == (struct archive_hash_entry *) NULL)
771 ret = ((struct archive_hash_entry *)
772 bfd_hash_allocate (table, sizeof (struct archive_hash_entry)));
773 if (ret == (struct archive_hash_entry *) NULL)
774 {
775 bfd_set_error (bfd_error_no_memory);
776 return NULL;
777 }
778
779 /* Call the allocation method of the superclass. */
780 ret = ((struct archive_hash_entry *)
781 bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));
782
783 if (ret)
784 {
785 /* Initialize the local fields. */
786 ret->defs = (struct archive_list *) NULL;
787 }
788
789 return (struct bfd_hash_entry *) ret;
790 }
791
792 /* Initialize an archive hash table. */
793
794 static boolean
795 archive_hash_table_init (table, newfunc)
796 struct archive_hash_table *table;
797 struct bfd_hash_entry *(*newfunc) PARAMS ((struct bfd_hash_entry *,
798 struct bfd_hash_table *,
799 const char *));
800 {
801 return bfd_hash_table_init (&table->table, newfunc);
802 }
803
804 /* Look up an entry in an archive hash table. */
805
806 #define archive_hash_lookup(t, string, create, copy) \
807 ((struct archive_hash_entry *) \
808 bfd_hash_lookup (&(t)->table, (string), (create), (copy)))
809
810 /* Free an archive hash table. */
811
812 #define archive_hash_table_free(t) bfd_hash_table_free (&(t)->table)
813
814 /* Generic function to add symbols from an archive file to the global
815 hash file. This function presumes that the archive symbol table
816 has already been read in (this is normally done by the
817 bfd_check_format entry point). It looks through the undefined and
818 common symbols and searches the archive symbol table for them. If
819 it finds an entry, it includes the associated object file in the
820 link.
821
822 The old linker looked through the archive symbol table for
823 undefined symbols. We do it the other way around, looking through
824 undefined symbols for symbols defined in the archive. The
825 advantage of the newer scheme is that we only have to look through
826 the list of undefined symbols once, whereas the old method had to
827 re-search the symbol table each time a new object file was added.
828
829 The CHECKFN argument is used to see if an object file should be
830 included. CHECKFN should set *PNEEDED to true if the object file
831 should be included, and must also call the bfd_link_info
832 add_archive_element callback function and handle adding the symbols
833 to the global hash table. CHECKFN should only return false if some
834 sort of error occurs.
835
836 For some formats, such as a.out, it is possible to look through an
837 object file but not actually include it in the link. The
838 archive_pass field in a BFD is used to avoid checking the symbols
839 of an object files too many times. When an object is included in
840 the link, archive_pass is set to -1. If an object is scanned but
841 not included, archive_pass is set to the pass number. The pass
842 number is incremented each time a new object file is included. The
843 pass number is used because when a new object file is included it
844 may create new undefined symbols which cause a previously examined
845 object file to be included. */
846
847 boolean
848 _bfd_generic_link_add_archive_symbols (abfd, info, checkfn)
849 bfd *abfd;
850 struct bfd_link_info *info;
851 boolean (*checkfn) PARAMS ((bfd *, struct bfd_link_info *,
852 boolean *pneeded));
853 {
854 carsym *arsyms;
855 carsym *arsym_end;
856 register carsym *arsym;
857 int pass;
858 struct archive_hash_table arsym_hash;
859 int indx;
860 struct bfd_link_hash_entry **pundef;
861
862 if (! bfd_has_map (abfd))
863 {
864 bfd_set_error (bfd_error_no_symbols);
865 return false;
866 }
867
868 arsyms = bfd_ardata (abfd)->symdefs;
869 arsym_end = arsyms + bfd_ardata (abfd)->symdef_count;
870
871 /* In order to quickly determine whether an symbol is defined in
872 this archive, we build a hash table of the symbols. */
873 if (! archive_hash_table_init (&arsym_hash, archive_hash_newfunc))
874 return false;
875 for (arsym = arsyms, indx = 0; arsym < arsym_end; arsym++, indx++)
876 {
877 struct archive_hash_entry *arh;
878 struct archive_list *l, **pp;
879
880 arh = archive_hash_lookup (&arsym_hash, arsym->name, true, false);
881 if (arh == (struct archive_hash_entry *) NULL)
882 goto error_return;
883 l = (struct archive_list *)
884 obstack_alloc (&(&(&arsym_hash)->table)->memory,
885 sizeof (struct archive_list));
886 if (l == NULL)
887 {
888 bfd_set_error (bfd_error_no_memory);
889 goto error_return;
890 }
891 l->indx = indx;
892 for (pp = &arh->defs;
893 *pp != (struct archive_list *) NULL;
894 pp = &(*pp)->next)
895 ;
896 *pp = l;
897 l->next = NULL;
898 }
899
900 pass = 1;
901
902 /* New undefined symbols are added to the end of the list, so we
903 only need to look through it once. */
904 pundef = &info->hash->undefs;
905 while (*pundef != (struct bfd_link_hash_entry *) NULL)
906 {
907 struct bfd_link_hash_entry *h;
908 struct archive_hash_entry *arh;
909 struct archive_list *l;
910
911 h = *pundef;
912
913 /* When a symbol is defined, it is not necessarily removed from
914 the list. */
915 if (h->type != bfd_link_hash_undefined
916 && h->type != bfd_link_hash_common)
917 {
918 /* Remove this entry from the list, for general cleanliness
919 and because we are going to look through the list again
920 if we search any more libraries. We can't remove the
921 entry if it is the tail, because that would lose any
922 entries we add to the list later on (it would also cause
923 us to lose track of whether the symbol has been
924 referenced). */
925 if (*pundef != info->hash->undefs_tail)
926 *pundef = (*pundef)->next;
927 else
928 pundef = &(*pundef)->next;
929 continue;
930 }
931
932 /* Look for this symbol in the archive symbol map. */
933 arh = archive_hash_lookup (&arsym_hash, h->root.string, false, false);
934 if (arh == (struct archive_hash_entry *) NULL)
935 {
936 pundef = &(*pundef)->next;
937 continue;
938 }
939
940 /* Look at all the objects which define this symbol. */
941 for (l = arh->defs; l != (struct archive_list *) NULL; l = l->next)
942 {
943 bfd *element;
944 boolean needed;
945
946 /* If the symbol has gotten defined along the way, quit. */
947 if (h->type != bfd_link_hash_undefined
948 && h->type != bfd_link_hash_common)
949 break;
950
951 element = bfd_get_elt_at_index (abfd, l->indx);
952 if (element == (bfd *) NULL)
953 goto error_return;
954
955 /* If we've already included this element, or if we've
956 already checked it on this pass, continue. */
957 if (element->archive_pass == -1
958 || element->archive_pass == pass)
959 continue;
960
961 /* If we can't figure this element out, just ignore it. */
962 if (! bfd_check_format (element, bfd_object))
963 {
964 element->archive_pass = -1;
965 continue;
966 }
967
968 /* CHECKFN will see if this element should be included, and
969 go ahead and include it if appropriate. */
970 if (! (*checkfn) (element, info, &needed))
971 goto error_return;
972
973 if (! needed)
974 element->archive_pass = pass;
975 else
976 {
977 element->archive_pass = -1;
978
979 /* Increment the pass count to show that we may need to
980 recheck object files which were already checked. */
981 ++pass;
982 }
983 }
984
985 pundef = &(*pundef)->next;
986 }
987
988 archive_hash_table_free (&arsym_hash);
989
990 return true;
991
992 error_return:
993 archive_hash_table_free (&arsym_hash);
994 return false;
995 }
996 \f
997 /* See if we should include an archive element. This version is used
998 when we do not want to automatically collect constructors based on
999 the symbol name, presumably because we have some other mechanism
1000 for finding them. */
1001
1002 static boolean
1003 generic_link_check_archive_element_no_collect (abfd, info, pneeded)
1004 bfd *abfd;
1005 struct bfd_link_info *info;
1006 boolean *pneeded;
1007 {
1008 return generic_link_check_archive_element (abfd, info, pneeded, false);
1009 }
1010
1011 /* See if we should include an archive element. This version is used
1012 when we want to automatically collect constructors based on the
1013 symbol name, as collect2 does. */
1014
1015 static boolean
1016 generic_link_check_archive_element_collect (abfd, info, pneeded)
1017 bfd *abfd;
1018 struct bfd_link_info *info;
1019 boolean *pneeded;
1020 {
1021 return generic_link_check_archive_element (abfd, info, pneeded, true);
1022 }
1023
1024 /* See if we should include an archive element. Optionally collect
1025 constructors. */
1026
1027 static boolean
1028 generic_link_check_archive_element (abfd, info, pneeded, collect)
1029 bfd *abfd;
1030 struct bfd_link_info *info;
1031 boolean *pneeded;
1032 boolean collect;
1033 {
1034 asymbol **pp, **ppend;
1035
1036 *pneeded = false;
1037
1038 if (! generic_link_read_symbols (abfd))
1039 return false;
1040
1041 pp = _bfd_generic_link_get_symbols (abfd);
1042 ppend = pp + _bfd_generic_link_get_symcount (abfd);
1043 for (; pp < ppend; pp++)
1044 {
1045 asymbol *p;
1046 struct bfd_link_hash_entry *h;
1047
1048 p = *pp;
1049
1050 /* We are only interested in globally visible symbols. */
1051 if (! bfd_is_com_section (p->section)
1052 && (p->flags & (BSF_GLOBAL | BSF_INDIRECT | BSF_WEAK)) == 0)
1053 continue;
1054
1055 /* We are only interested if we know something about this
1056 symbol, and it is undefined or common. An undefined weak
1057 symbol (type bfd_link_hash_weak) is not considered to be a
1058 reference when pulling files out of an archive. See the SVR4
1059 ABI, p. 4-27. */
1060 h = bfd_link_hash_lookup (info->hash, bfd_asymbol_name (p), false,
1061 false, true);
1062 if (h == (struct bfd_link_hash_entry *) NULL
1063 || (h->type != bfd_link_hash_undefined
1064 && h->type != bfd_link_hash_common))
1065 continue;
1066
1067 /* P is a symbol we are looking for. */
1068
1069 if (! bfd_is_com_section (p->section))
1070 {
1071 bfd_size_type symcount;
1072 asymbol **symbols;
1073
1074 /* This object file defines this symbol, so pull it in. */
1075 if (! (*info->callbacks->add_archive_element) (info, abfd,
1076 bfd_asymbol_name (p)))
1077 return false;
1078 symcount = _bfd_generic_link_get_symcount (abfd);
1079 symbols = _bfd_generic_link_get_symbols (abfd);
1080 if (! generic_link_add_symbol_list (abfd, info, symcount,
1081 symbols, collect))
1082 return false;
1083 *pneeded = true;
1084 return true;
1085 }
1086
1087 /* P is a common symbol. */
1088
1089 if (h->type == bfd_link_hash_undefined)
1090 {
1091 bfd *symbfd;
1092
1093 symbfd = h->u.undef.abfd;
1094 if (symbfd == (bfd *) NULL)
1095 {
1096 /* This symbol was created as undefined from outside
1097 BFD. We assume that we should link in the object
1098 file. This is for the -u option in the linker. */
1099 if (! (*info->callbacks->add_archive_element)
1100 (info, abfd, bfd_asymbol_name (p)))
1101 return false;
1102 *pneeded = true;
1103 return true;
1104 }
1105
1106 /* Turn the symbol into a common symbol but do not link in
1107 the object file. This is how a.out works. Object
1108 formats that require different semantics must implement
1109 this function differently. This symbol is already on the
1110 undefs list. We add the section to a common section
1111 attached to symbfd to ensure that it is in a BFD which
1112 will be linked in. */
1113 h->type = bfd_link_hash_common;
1114 h->u.c.size = bfd_asymbol_value (p);
1115 if (p->section == &bfd_com_section)
1116 h->u.c.section = bfd_make_section_old_way (symbfd, "COMMON");
1117 else
1118 h->u.c.section = bfd_make_section_old_way (symbfd,
1119 p->section->name);
1120 h->u.c.section->flags = SEC_ALLOC;
1121 }
1122 else
1123 {
1124 /* Adjust the size of the common symbol if necessary. This
1125 is how a.out works. Object formats that require
1126 different semantics must implement this function
1127 differently. */
1128 if (bfd_asymbol_value (p) > h->u.c.size)
1129 h->u.c.size = bfd_asymbol_value (p);
1130 }
1131 }
1132
1133 /* This archive element is not needed. */
1134 return true;
1135 }
1136
1137 /* Add the symbols from an object file to the global hash table. ABFD
1138 is the object file. INFO is the linker information. SYMBOL_COUNT
1139 is the number of symbols. SYMBOLS is the list of symbols. COLLECT
1140 is true if constructors should be automatically collected by name
1141 as is done by collect2. */
1142
1143 static boolean
1144 generic_link_add_symbol_list (abfd, info, symbol_count, symbols, collect)
1145 bfd *abfd;
1146 struct bfd_link_info *info;
1147 bfd_size_type symbol_count;
1148 asymbol **symbols;
1149 boolean collect;
1150 {
1151 asymbol **pp, **ppend;
1152
1153 pp = symbols;
1154 ppend = symbols + symbol_count;
1155 for (; pp < ppend; pp++)
1156 {
1157 asymbol *p;
1158
1159 p = *pp;
1160
1161 if ((p->flags & (BSF_INDIRECT
1162 | BSF_WARNING
1163 | BSF_GLOBAL
1164 | BSF_CONSTRUCTOR
1165 | BSF_WEAK)) != 0
1166 || bfd_get_section (p) == &bfd_und_section
1167 || bfd_is_com_section (bfd_get_section (p))
1168 || bfd_get_section (p) == &bfd_ind_section)
1169 {
1170 const char *name;
1171 const char *string;
1172 struct generic_link_hash_entry *h;
1173
1174 name = bfd_asymbol_name (p);
1175 if ((p->flags & BSF_INDIRECT) != 0
1176 || p->section == &bfd_ind_section)
1177 string = bfd_asymbol_name ((asymbol *) p->value);
1178 else if ((p->flags & BSF_WARNING) != 0)
1179 {
1180 /* The name of P is actually the warning string, and the
1181 value is actually a pointer to the symbol to warn
1182 about. */
1183 string = name;
1184 name = bfd_asymbol_name ((asymbol *) p->value);
1185 }
1186 else
1187 string = NULL;
1188
1189 h = NULL;
1190 if (! (_bfd_generic_link_add_one_symbol
1191 (info, abfd, name, p->flags, bfd_get_section (p),
1192 p->value, string, false, collect,
1193 (struct bfd_link_hash_entry **) &h)))
1194 return false;
1195
1196 /* Save the BFD symbol so that we don't lose any backend
1197 specific information that may be attached to it. We only
1198 want this one if it gives more information than the
1199 existing one; we don't want to replace a defined symbol
1200 with an undefined one. This routine may be called with a
1201 hash table other than the generic hash table, so we only
1202 do this if we are certain that the hash table is a
1203 generic one. */
1204 if (info->hash->creator == abfd->xvec)
1205 {
1206 if (h->sym == (asymbol *) NULL
1207 || (bfd_get_section (p) != &bfd_und_section
1208 && (! bfd_is_com_section (bfd_get_section (p))
1209 || (bfd_get_section (h->sym) == &bfd_und_section))))
1210 {
1211 h->sym = p;
1212 /* BSF_OLD_COMMON is a hack to support COFF reloc
1213 reading, and it should go away when the COFF
1214 linker is switched to the new version. */
1215 if (bfd_is_com_section (bfd_get_section (p)))
1216 p->flags |= BSF_OLD_COMMON;
1217 }
1218
1219 /* Store a back pointer from the symbol to the hash
1220 table entry for the benefit of relaxation code until
1221 it gets rewritten to not use asymbol structures. */
1222 p->udata = (PTR) h;
1223 }
1224 }
1225 }
1226
1227 return true;
1228 }
1229 \f
1230 /* We use a state table to deal with adding symbols from an object
1231 file. The first index into the state table describes the symbol
1232 from the object file. The second index into the state table is the
1233 type of the symbol in the hash table. */
1234
1235 /* The symbol from the object file is turned into one of these row
1236 values. */
1237
1238 enum link_row
1239 {
1240 UNDEF_ROW, /* Undefined. */
1241 UNDEFW_ROW, /* Weak undefined. */
1242 DEF_ROW, /* Defined. */
1243 DEFW_ROW, /* Weak defined. */
1244 COMMON_ROW, /* Common. */
1245 INDR_ROW, /* Indirect. */
1246 WARN_ROW, /* Warning. */
1247 SET_ROW /* Member of set. */
1248 };
1249
1250 /* The actions to take in the state table. */
1251
1252 enum link_action
1253 {
1254 FAIL, /* Abort. */
1255 UND, /* Mark symbol undefined. */
1256 WEAK, /* Mark symbol weak undefined. */
1257 DEF, /* Mark symbol defined. */
1258 COM, /* Mark symbol common. */
1259 REF, /* Mark defined symbol referenced. */
1260 CREF, /* Possibly warn about common reference to defined symbol. */
1261 CDEF, /* Define existing common symbol. */
1262 NOACT, /* No action. */
1263 BIG, /* Mark symbol common using largest size. */
1264 MDEF, /* Multiple definition error. */
1265 MIND, /* Multiple indirect symbols. */
1266 IND, /* Make indirect symbol. */
1267 SET, /* Add value to set. */
1268 MWARN, /* Make warning symbol. */
1269 WARN, /* Issue warning. */
1270 CWARN, /* Warn if referenced, else MWARN. */
1271 CYCLE, /* Repeat with symbol pointed to. */
1272 REFC, /* Mark indirect symbol referenced and then CYCLE. */
1273 WARNC /* Issue warning and then CYCLE. */
1274 };
1275
1276 /* The state table itself. The first index is a link_row and the
1277 second index is a bfd_link_hash_type. */
1278
1279 static const enum link_action link_action[8][7] =
1280 {
1281 /* current\prev new undef weak def com indr warn */
1282 /* UNDEF_ROW */ {UND, NOACT, NOACT, REF, NOACT, REFC, WARNC },
1283 /* UNDEFW_ROW */ {WEAK, WEAK, NOACT, REF, NOACT, REFC, WARNC },
1284 /* DEF_ROW */ {DEF, DEF, DEF, MDEF, CDEF, MDEF, CYCLE },
1285 /* DEFW_ROW */ {DEF, DEF, DEF, NOACT, NOACT, NOACT, CYCLE },
1286 /* COMMON_ROW */ {COM, COM, COM, CREF, BIG, MDEF, WARNC },
1287 /* INDR_ROW */ {IND, IND, IND, MDEF, MDEF, MIND, CYCLE },
1288 /* WARN_ROW */ {MWARN, WARN, WARN, CWARN, WARN, CWARN, CYCLE },
1289 /* SET_ROW */ {SET, SET, SET, SET, SET, CYCLE, CYCLE }
1290 };
1291
1292 /* Most of the entries in the LINK_ACTION table are straightforward,
1293 but a few are somewhat subtle.
1294
1295 A reference to an indirect symbol (UNDEF_ROW/indr or
1296 UNDEFW_ROW/indr) is counted as a reference both to the indirect
1297 symbol and to the symbol the indirect symbol points to.
1298
1299 A reference to a warning symbol (UNDEF_ROW/warn or UNDEFW_ROW/warn)
1300 causes the warning to be issued.
1301
1302 A common definition of an indirect symbol (COMMON_ROW/indr) is
1303 treated as a multiple definition error. Likewise for an indirect
1304 definition of a common symbol (INDR_ROW/com).
1305
1306 An indirect definition of a warning (INDR_ROW/warn) does not cause
1307 the warning to be issued.
1308
1309 If a warning is created for an indirect symbol (WARN_ROW/indr) no
1310 warning is created for the symbol the indirect symbol points to.
1311
1312 Adding an entry to a set does not count as a reference to a set,
1313 and no warning is issued (SET_ROW/warn). */
1314
1315 /* Add a symbol to the global hash table.
1316 ABFD is the BFD the symbol comes from.
1317 NAME is the name of the symbol.
1318 FLAGS is the BSF_* bits associated with the symbol.
1319 SECTION is the section in which the symbol is defined; this may be
1320 bfd_und_section or bfd_com_section.
1321 VALUE is the value of the symbol, relative to the section.
1322 STRING is used for either an indirect symbol, in which case it is
1323 the name of the symbol to indirect to, or a warning symbol, in
1324 which case it is the warning string.
1325 COPY is true if NAME or STRING must be copied into locally
1326 allocated memory if they need to be saved.
1327 COLLECT is true if we should automatically collect gcc constructor
1328 or destructor names as collect2 does.
1329 HASHP, if not NULL, is a place to store the created hash table
1330 entry; if *HASHP is not NULL, the caller has already looked up
1331 the hash table entry, and stored it in *HASHP. */
1332
1333 boolean
1334 _bfd_generic_link_add_one_symbol (info, abfd, name, flags, section, value,
1335 string, copy, collect, hashp)
1336 struct bfd_link_info *info;
1337 bfd *abfd;
1338 const char *name;
1339 flagword flags;
1340 asection *section;
1341 bfd_vma value;
1342 const char *string;
1343 boolean copy;
1344 boolean collect;
1345 struct bfd_link_hash_entry **hashp;
1346 {
1347 enum link_row row;
1348 struct bfd_link_hash_entry *h;
1349 boolean cycle;
1350
1351 if (section == &bfd_ind_section
1352 || (flags & BSF_INDIRECT) != 0)
1353 row = INDR_ROW;
1354 else if ((flags & BSF_WARNING) != 0)
1355 row = WARN_ROW;
1356 else if ((flags & BSF_CONSTRUCTOR) != 0)
1357 row = SET_ROW;
1358 else if (section == &bfd_und_section)
1359 {
1360 if ((flags & BSF_WEAK) != 0)
1361 row = UNDEFW_ROW;
1362 else
1363 row = UNDEF_ROW;
1364 }
1365 else if ((flags & BSF_WEAK) != 0)
1366 row = DEFW_ROW;
1367 else if (bfd_is_com_section (section))
1368 row = COMMON_ROW;
1369 else
1370 row = DEF_ROW;
1371
1372 if (hashp != NULL && *hashp != NULL)
1373 {
1374 h = *hashp;
1375 BFD_ASSERT (strcmp (h->root.string, name) == 0);
1376 }
1377 else
1378 {
1379 h = bfd_link_hash_lookup (info->hash, name, true, copy, false);
1380 if (h == NULL)
1381 {
1382 if (hashp != NULL)
1383 *hashp = NULL;
1384 return false;
1385 }
1386 }
1387
1388 if (info->notice_hash != (struct bfd_hash_table *) NULL
1389 && (bfd_hash_lookup (info->notice_hash, name, false, false)
1390 != (struct bfd_hash_entry *) NULL))
1391 {
1392 if (! (*info->callbacks->notice) (info, name, abfd, section, value))
1393 return false;
1394 }
1395
1396 if (hashp != (struct bfd_link_hash_entry **) NULL)
1397 *hashp = h;
1398
1399 do
1400 {
1401 enum link_action action;
1402
1403 cycle = false;
1404 action = link_action[(int) row][(int) h->type];
1405 switch (action)
1406 {
1407 case FAIL:
1408 abort ();
1409
1410 case NOACT:
1411 /* Do nothing. */
1412 break;
1413
1414 case UND:
1415 /* Make a new undefined symbol. */
1416 h->type = bfd_link_hash_undefined;
1417 h->u.undef.abfd = abfd;
1418 bfd_link_add_undef (info->hash, h);
1419 break;
1420
1421 case WEAK:
1422 /* Make a new weak undefined symbol. */
1423 h->type = bfd_link_hash_weak;
1424 h->u.undef.abfd = abfd;
1425 break;
1426
1427 case CDEF:
1428 /* We have found a definition for a symbol which was
1429 previously common. */
1430 BFD_ASSERT (h->type == bfd_link_hash_common);
1431 if (! ((*info->callbacks->multiple_common)
1432 (info, name,
1433 h->u.c.section->owner, bfd_link_hash_common, h->u.c.size,
1434 abfd, bfd_link_hash_defined, (bfd_vma) 0)))
1435 return false;
1436 /* Fall through. */
1437 case DEF:
1438 /* Define a symbol. */
1439 h->type = bfd_link_hash_defined;
1440 h->u.def.section = section;
1441 h->u.def.value = value;
1442
1443 /* If we have been asked to, we act like collect2 and
1444 identify all functions that might be global constructors
1445 and destructors and pass them up in a callback. We only
1446 do this for certain object file types, since many object
1447 file types can handle this automatically. */
1448 if (collect && name[0] == '_')
1449 {
1450 const char *s;
1451
1452 /* A constructor or destructor name starts like this:
1453 _+GLOBAL_[_.$][ID][_.$]
1454 where the first [_.$] and the second are the same
1455 character (we accept any character there, in case a
1456 new object file format comes along with even worse
1457 naming restrictions). */
1458
1459 #define CONS_PREFIX "GLOBAL_"
1460 #define CONS_PREFIX_LEN (sizeof CONS_PREFIX - 1)
1461
1462 s = name + 1;
1463 while (*s == '_')
1464 ++s;
1465 if (s[0] == 'G'
1466 && strncmp (s, CONS_PREFIX, CONS_PREFIX_LEN - 1) == 0)
1467 {
1468 char c;
1469
1470 c = s[CONS_PREFIX_LEN + 1];
1471 if ((c == 'I' || c == 'D')
1472 && s[CONS_PREFIX_LEN] == s[CONS_PREFIX_LEN + 2])
1473 {
1474 if (! ((*info->callbacks->constructor)
1475 (info,
1476 c == 'I' ? true : false,
1477 name, abfd, section, value)))
1478 return false;
1479 }
1480 }
1481 }
1482
1483 break;
1484
1485 case COM:
1486 /* We have found a common definition for a symbol. */
1487 if (h->type == bfd_link_hash_new)
1488 bfd_link_add_undef (info->hash, h);
1489 h->type = bfd_link_hash_common;
1490 h->u.c.size = value;
1491 if (section == &bfd_com_section)
1492 {
1493 h->u.c.section = bfd_make_section_old_way (abfd, "COMMON");
1494 h->u.c.section->flags = SEC_ALLOC;
1495 }
1496 else if (section->owner != abfd)
1497 {
1498 h->u.c.section = bfd_make_section_old_way (abfd, section->name);
1499 h->u.c.section->flags = SEC_ALLOC;
1500 }
1501 else
1502 h->u.c.section = section;
1503 break;
1504
1505 case REF:
1506 /* A reference to a defined symbol. */
1507 if (h->next == NULL && info->hash->undefs_tail != h)
1508 h->next = h;
1509 break;
1510
1511 case BIG:
1512 /* We have found a common definition for a symbol which
1513 already had a common definition. Use the maximum of the
1514 two sizes. */
1515 BFD_ASSERT (h->type == bfd_link_hash_common);
1516 if (! ((*info->callbacks->multiple_common)
1517 (info, name,
1518 h->u.c.section->owner, bfd_link_hash_common, h->u.c.size,
1519 abfd, bfd_link_hash_common, value)))
1520 return false;
1521 if (value > h->u.c.size)
1522 h->u.c.size = value;
1523 break;
1524
1525 case CREF:
1526 /* We have found a common definition for a symbol which was
1527 already defined. */
1528 BFD_ASSERT (h->type == bfd_link_hash_defined);
1529 if (! ((*info->callbacks->multiple_common)
1530 (info, name,
1531 h->u.def.section->owner, bfd_link_hash_defined, (bfd_vma) 0,
1532 abfd, bfd_link_hash_common, value)))
1533 return false;
1534 break;
1535
1536 case MIND:
1537 /* Multiple indirect symbols. This is OK if they both point
1538 to the same symbol. */
1539 if (strcmp (h->u.i.link->root.string, string) == 0)
1540 break;
1541 /* Fall through. */
1542 case MDEF:
1543 /* Handle a multiple definition. */
1544 {
1545 asection *msec;
1546 bfd_vma mval;
1547
1548 switch (h->type)
1549 {
1550 case bfd_link_hash_defined:
1551 msec = h->u.def.section;
1552 mval = h->u.def.value;
1553 break;
1554 case bfd_link_hash_common:
1555 msec = &bfd_com_section;
1556 mval = h->u.c.size;
1557 break;
1558 case bfd_link_hash_indirect:
1559 msec = &bfd_ind_section;
1560 mval = 0;
1561 break;
1562 default:
1563 abort ();
1564 }
1565
1566 if (! ((*info->callbacks->multiple_definition)
1567 (info, name, msec->owner, msec, mval, abfd, section,
1568 value)))
1569 return false;
1570 }
1571 break;
1572
1573 case IND:
1574 /* Create an indirect symbol. */
1575 {
1576 struct bfd_link_hash_entry *inh;
1577
1578 /* STRING is the name of the symbol we want to indirect
1579 to. */
1580 inh = bfd_link_hash_lookup (info->hash, string, true, copy,
1581 false);
1582 if (inh == (struct bfd_link_hash_entry *) NULL)
1583 return false;
1584 if (inh->type == bfd_link_hash_new)
1585 {
1586 inh->type = bfd_link_hash_undefined;
1587 inh->u.undef.abfd = abfd;
1588 bfd_link_add_undef (info->hash, inh);
1589 }
1590
1591 /* If the indirect symbol has been referenced, we need to
1592 push the reference down to the symbol we are
1593 referencing. */
1594 if (h->type != bfd_link_hash_new)
1595 {
1596 row = UNDEF_ROW;
1597 cycle = true;
1598 }
1599
1600 h->type = bfd_link_hash_indirect;
1601 h->u.i.link = inh;
1602 }
1603 break;
1604
1605 case SET:
1606 /* Add an entry to a set. */
1607 if (! (*info->callbacks->add_to_set) (info, h, BFD_RELOC_CTOR,
1608 abfd, section, value))
1609 return false;
1610 break;
1611
1612 case WARNC:
1613 /* Issue a warning and cycle. */
1614 if (h->u.i.warning != NULL)
1615 {
1616 if (! (*info->callbacks->warning) (info, h->u.i.warning))
1617 return false;
1618 /* Only issue a warning once. */
1619 h->u.i.warning = NULL;
1620 }
1621 /* Fall through. */
1622 case CYCLE:
1623 /* Try again with the referenced symbol. */
1624 h = h->u.i.link;
1625 cycle = true;
1626 break;
1627
1628 case REFC:
1629 /* A reference to an indirect symbol. */
1630 if (h->next == NULL && info->hash->undefs_tail != h)
1631 h->next = h;
1632 h = h->u.i.link;
1633 cycle = true;
1634 break;
1635
1636 case WARN:
1637 /* Issue a warning. */
1638 if (! (*info->callbacks->warning) (info, string))
1639 return false;
1640 break;
1641
1642 case CWARN:
1643 /* Warn if this symbol has been referenced already,
1644 otherwise either add a warning or cycle. A symbol has
1645 been referenced if the next field is not NULL, or it is
1646 the tail of the undefined symbol list. The REF case
1647 above helps to ensure this. */
1648 if (h->next != NULL || info->hash->undefs_tail == h)
1649 {
1650 if (! (*info->callbacks->warning) (info, string))
1651 return false;
1652 break;
1653 }
1654 /* Fall through. */
1655 case MWARN:
1656 /* Make a warning symbol. */
1657 {
1658 struct bfd_link_hash_entry *sub;
1659
1660 /* STRING is the warning to give. */
1661 sub = ((struct bfd_link_hash_entry *)
1662 bfd_hash_allocate (&info->hash->table,
1663 sizeof (struct bfd_link_hash_entry)));
1664 if (!sub)
1665 {
1666 bfd_set_error (bfd_error_no_memory);
1667 return false;
1668 }
1669 *sub = *h;
1670 h->type = bfd_link_hash_warning;
1671 h->u.i.link = sub;
1672 if (! copy)
1673 h->u.i.warning = string;
1674 else
1675 {
1676 char *w;
1677
1678 w = bfd_hash_allocate (&info->hash->table,
1679 strlen (string) + 1);
1680 strcpy (w, string);
1681 h->u.i.warning = w;
1682 }
1683 }
1684 break;
1685 }
1686 }
1687 while (cycle);
1688
1689 return true;
1690 }
1691 \f
1692 /* Generic final link routine. */
1693
1694 boolean
1695 _bfd_generic_final_link (abfd, info)
1696 bfd *abfd;
1697 struct bfd_link_info *info;
1698 {
1699 bfd *sub;
1700 asection *o;
1701 struct bfd_link_order *p;
1702 size_t outsymalloc;
1703 struct generic_write_global_symbol_info wginfo;
1704
1705 abfd->outsymbols = (asymbol **) NULL;
1706 abfd->symcount = 0;
1707 outsymalloc = 0;
1708
1709 /* Build the output symbol table. */
1710 for (sub = info->input_bfds; sub != (bfd *) NULL; sub = sub->link_next)
1711 if (! _bfd_generic_link_output_symbols (abfd, sub, info, &outsymalloc))
1712 return false;
1713
1714 /* Accumulate the global symbols. */
1715 wginfo.info = info;
1716 wginfo.output_bfd = abfd;
1717 wginfo.psymalloc = &outsymalloc;
1718 _bfd_generic_link_hash_traverse (_bfd_generic_hash_table (info),
1719 _bfd_generic_link_write_global_symbol,
1720 (PTR) &wginfo);
1721
1722 if (info->relocateable)
1723 {
1724 /* Allocate space for the output relocs for each section. */
1725 for (o = abfd->sections;
1726 o != (asection *) NULL;
1727 o = o->next)
1728 {
1729 o->reloc_count = 0;
1730 for (p = o->link_order_head;
1731 p != (struct bfd_link_order *) NULL;
1732 p = p->next)
1733 {
1734 if (p->type == bfd_section_reloc_link_order
1735 || p->type == bfd_symbol_reloc_link_order)
1736 ++o->reloc_count;
1737 else if (p->type == bfd_indirect_link_order)
1738 {
1739 asection *input_section;
1740 bfd *input_bfd;
1741 long relsize;
1742 arelent **relocs;
1743 asymbol **symbols;
1744 long reloc_count;
1745
1746 input_section = p->u.indirect.section;
1747 input_bfd = input_section->owner;
1748 relsize = bfd_get_reloc_upper_bound (input_bfd,
1749 input_section);
1750 if (relsize < 0)
1751 return false;
1752 relocs = (arelent **) malloc ((size_t) relsize);
1753 if (!relocs && relsize != 0)
1754 {
1755 bfd_set_error (bfd_error_no_memory);
1756 return false;
1757 }
1758 symbols = _bfd_generic_link_get_symbols (input_bfd);
1759 reloc_count = bfd_canonicalize_reloc (input_bfd,
1760 input_section,
1761 relocs,
1762 symbols);
1763 if (reloc_count < 0)
1764 return false;
1765 BFD_ASSERT (reloc_count == input_section->reloc_count);
1766 o->reloc_count += reloc_count;
1767 free (relocs);
1768 }
1769 }
1770 if (o->reloc_count > 0)
1771 {
1772 o->orelocation = ((arelent **)
1773 bfd_alloc (abfd,
1774 (o->reloc_count
1775 * sizeof (arelent *))));
1776 if (!o->orelocation)
1777 {
1778 bfd_set_error (bfd_error_no_memory);
1779 return false;
1780 }
1781 o->flags |= SEC_RELOC;
1782 /* Reset the count so that it can be used as an index
1783 when putting in the output relocs. */
1784 o->reloc_count = 0;
1785 }
1786 }
1787 }
1788
1789 /* Handle all the link order information for the sections. */
1790 for (o = abfd->sections;
1791 o != (asection *) NULL;
1792 o = o->next)
1793 {
1794 for (p = o->link_order_head;
1795 p != (struct bfd_link_order *) NULL;
1796 p = p->next)
1797 {
1798 switch (p->type)
1799 {
1800 case bfd_section_reloc_link_order:
1801 case bfd_symbol_reloc_link_order:
1802 if (! _bfd_generic_reloc_link_order (abfd, info, o, p))
1803 return false;
1804 break;
1805 default:
1806 if (! _bfd_default_link_order (abfd, info, o, p))
1807 return false;
1808 break;
1809 }
1810 }
1811 }
1812
1813 return true;
1814 }
1815
1816 /* Add an output symbol to the output BFD. */
1817
1818 static boolean
1819 generic_add_output_symbol (output_bfd, psymalloc, sym)
1820 bfd *output_bfd;
1821 size_t *psymalloc;
1822 asymbol *sym;
1823 {
1824 if (output_bfd->symcount >= *psymalloc)
1825 {
1826 asymbol **newsyms;
1827
1828 if (*psymalloc == 0)
1829 *psymalloc = 124;
1830 else
1831 *psymalloc *= 2;
1832 if (output_bfd->outsymbols == (asymbol **) NULL)
1833 newsyms = (asymbol **) malloc (*psymalloc * sizeof (asymbol *));
1834 else
1835 newsyms = (asymbol **) realloc (output_bfd->outsymbols,
1836 *psymalloc * sizeof (asymbol *));
1837 if (newsyms == (asymbol **) NULL)
1838 {
1839 bfd_set_error (bfd_error_no_memory);
1840 return false;
1841 }
1842 output_bfd->outsymbols = newsyms;
1843 }
1844
1845 output_bfd->outsymbols[output_bfd->symcount] = sym;
1846 ++output_bfd->symcount;
1847
1848 return true;
1849 }
1850
1851 /* Handle the symbols for an input BFD. */
1852
1853 boolean
1854 _bfd_generic_link_output_symbols (output_bfd, input_bfd, info, psymalloc)
1855 bfd *output_bfd;
1856 bfd *input_bfd;
1857 struct bfd_link_info *info;
1858 size_t *psymalloc;
1859 {
1860 asymbol **sym_ptr;
1861 asymbol **sym_end;
1862
1863 if (! generic_link_read_symbols (input_bfd))
1864 return false;
1865
1866 /* Create a filename symbol if we are supposed to. */
1867 if (info->create_object_symbols_section != (asection *) NULL)
1868 {
1869 asection *sec;
1870
1871 for (sec = input_bfd->sections;
1872 sec != (asection *) NULL;
1873 sec = sec->next)
1874 {
1875 if (sec->output_section == info->create_object_symbols_section)
1876 {
1877 asymbol *newsym;
1878
1879 newsym = bfd_make_empty_symbol (input_bfd);
1880 if (!newsym)
1881 return false;
1882 newsym->name = input_bfd->filename;
1883 newsym->value = 0;
1884 newsym->flags = BSF_LOCAL | BSF_FILE;
1885 newsym->section = sec;
1886
1887 if (! generic_add_output_symbol (output_bfd, psymalloc,
1888 newsym))
1889 return false;
1890
1891 break;
1892 }
1893 }
1894 }
1895
1896 /* Adjust the values of the globally visible symbols, and write out
1897 local symbols. */
1898 sym_ptr = _bfd_generic_link_get_symbols (input_bfd);
1899 sym_end = sym_ptr + _bfd_generic_link_get_symcount (input_bfd);
1900 for (; sym_ptr < sym_end; sym_ptr++)
1901 {
1902 asymbol *sym;
1903 struct generic_link_hash_entry *h;
1904 boolean output;
1905
1906 h = (struct generic_link_hash_entry *) NULL;
1907 sym = *sym_ptr;
1908 if ((sym->flags & (BSF_INDIRECT
1909 | BSF_WARNING
1910 | BSF_GLOBAL
1911 | BSF_CONSTRUCTOR
1912 | BSF_WEAK)) != 0
1913 || bfd_get_section (sym) == &bfd_und_section
1914 || bfd_is_com_section (bfd_get_section (sym))
1915 || bfd_get_section (sym) == &bfd_ind_section)
1916 {
1917 h = _bfd_generic_link_hash_lookup (_bfd_generic_hash_table (info),
1918 bfd_asymbol_name (sym),
1919 false, false, true);
1920 if (h != (struct generic_link_hash_entry *) NULL)
1921 {
1922 /* Force all references to this symbol to point to
1923 the same area in memory. It is possible that
1924 this routine will be called with a hash table
1925 other than a generic hash table, so we double
1926 check that. */
1927 if (info->hash->creator == input_bfd->xvec)
1928 {
1929 if (h->sym != (asymbol *) NULL)
1930 *sym_ptr = sym = h->sym;
1931 }
1932
1933 switch (h->root.type)
1934 {
1935 default:
1936 case bfd_link_hash_new:
1937 abort ();
1938 case bfd_link_hash_undefined:
1939 case bfd_link_hash_weak:
1940 break;
1941 case bfd_link_hash_defined:
1942 sym->value = h->root.u.def.value;
1943 sym->section = h->root.u.def.section;
1944 sym->flags |= BSF_GLOBAL;
1945 break;
1946 case bfd_link_hash_common:
1947 sym->value = h->root.u.c.size;
1948 sym->flags |= BSF_GLOBAL;
1949 if (! bfd_is_com_section (sym->section))
1950 {
1951 BFD_ASSERT (sym->section == &bfd_und_section);
1952 sym->section = &bfd_com_section;
1953 }
1954 /* We do not set the section of the symbol to
1955 h->root.u.c.section. That value was saved so
1956 that we would know where to allocate the symbol
1957 if it was defined. In this case the type is
1958 still bfd_link_hash_common, so we did not define
1959 it, so we do not want to use that section. */
1960 break;
1961 }
1962 }
1963 }
1964
1965 /* This switch is straight from the old code in
1966 write_file_locals in ldsym.c. */
1967 if (info->strip == strip_some
1968 && (bfd_hash_lookup (info->keep_hash, bfd_asymbol_name (sym),
1969 false, false)
1970 == (struct bfd_hash_entry *) NULL))
1971 output = false;
1972 else if ((sym->flags & (BSF_GLOBAL | BSF_WEAK)) != 0)
1973 {
1974 /* If this symbol is marked as occurring now, rather
1975 than at the end, output it now. This is used for
1976 COFF C_EXT FCN symbols. FIXME: There must be a
1977 better way. */
1978 if (bfd_asymbol_bfd (sym) == input_bfd
1979 && (sym->flags & BSF_NOT_AT_END) != 0)
1980 output = true;
1981 else
1982 output = false;
1983 }
1984 else if (sym->section == &bfd_ind_section)
1985 output = false;
1986 else if ((sym->flags & BSF_DEBUGGING) != 0)
1987 {
1988 if (info->strip == strip_none)
1989 output = true;
1990 else
1991 output = false;
1992 }
1993 else if (sym->section == &bfd_und_section
1994 || bfd_is_com_section (sym->section))
1995 output = false;
1996 else if ((sym->flags & BSF_LOCAL) != 0)
1997 {
1998 if ((sym->flags & BSF_WARNING) != 0)
1999 output = false;
2000 else
2001 {
2002 switch (info->discard)
2003 {
2004 default:
2005 case discard_all:
2006 output = false;
2007 break;
2008 case discard_l:
2009 if (bfd_asymbol_name (sym)[0] == info->lprefix[0]
2010 && (info->lprefix_len == 1
2011 || strncmp (bfd_asymbol_name (sym), info->lprefix,
2012 info->lprefix_len) == 0))
2013 output = false;
2014 else
2015 output = true;
2016 break;
2017 case discard_none:
2018 output = true;
2019 break;
2020 }
2021 }
2022 }
2023 else if ((sym->flags & BSF_CONSTRUCTOR))
2024 {
2025 if (info->strip != strip_all)
2026 output = true;
2027 else
2028 output = false;
2029 }
2030 else
2031 abort ();
2032
2033 if (output)
2034 {
2035 if (! generic_add_output_symbol (output_bfd, psymalloc, sym))
2036 return false;
2037 if (h != (struct generic_link_hash_entry *) NULL)
2038 h->written = true;
2039 }
2040 }
2041
2042 return true;
2043 }
2044
2045 /* Write out a global symbol, if it hasn't already been written out.
2046 This is called for each symbol in the hash table. */
2047
2048 boolean
2049 _bfd_generic_link_write_global_symbol (h, data)
2050 struct generic_link_hash_entry *h;
2051 PTR data;
2052 {
2053 struct generic_write_global_symbol_info *wginfo =
2054 (struct generic_write_global_symbol_info *) data;
2055 asymbol *sym;
2056
2057 if (h->written)
2058 return true;
2059
2060 h->written = true;
2061
2062 if (wginfo->info->strip == strip_all
2063 || (wginfo->info->strip == strip_some
2064 && bfd_hash_lookup (wginfo->info->keep_hash, h->root.root.string,
2065 false, false) == NULL))
2066 return true;
2067
2068 if (h->sym != (asymbol *) NULL)
2069 {
2070 sym = h->sym;
2071 BFD_ASSERT (strcmp (bfd_asymbol_name (sym), h->root.root.string) == 0);
2072 }
2073 else
2074 {
2075 sym = bfd_make_empty_symbol (wginfo->output_bfd);
2076 if (!sym)
2077 return false;
2078 sym->name = h->root.root.string;
2079 sym->flags = 0;
2080 }
2081
2082 switch (h->root.type)
2083 {
2084 default:
2085 case bfd_link_hash_new:
2086 abort ();
2087 case bfd_link_hash_undefined:
2088 sym->section = &bfd_und_section;
2089 sym->value = 0;
2090 break;
2091 case bfd_link_hash_weak:
2092 sym->section = &bfd_und_section;
2093 sym->value = 0;
2094 sym->flags |= BSF_WEAK;
2095 break;
2096 case bfd_link_hash_defined:
2097 sym->section = h->root.u.def.section;
2098 sym->value = h->root.u.def.value;
2099 break;
2100 case bfd_link_hash_common:
2101 sym->value = h->root.u.c.size;
2102 if (sym->section == NULL)
2103 sym->section = &bfd_com_section;
2104 else if (! bfd_is_com_section (sym->section))
2105 {
2106 BFD_ASSERT (sym->section == &bfd_und_section);
2107 sym->section = &bfd_com_section;
2108 }
2109 /* Do not set the section; see _bfd_generic_link_output_symbols. */
2110 break;
2111 case bfd_link_hash_indirect:
2112 case bfd_link_hash_warning:
2113 /* FIXME: What should we do here? */
2114 break;
2115 }
2116
2117 sym->flags |= BSF_GLOBAL;
2118
2119 if (! generic_add_output_symbol (wginfo->output_bfd, wginfo->psymalloc,
2120 sym))
2121 {
2122 /* FIXME: No way to return failure. */
2123 abort ();
2124 }
2125
2126 return true;
2127 }
2128
2129 /* Create a relocation. */
2130
2131 boolean
2132 _bfd_generic_reloc_link_order (abfd, info, sec, link_order)
2133 bfd *abfd;
2134 struct bfd_link_info *info;
2135 asection *sec;
2136 struct bfd_link_order *link_order;
2137 {
2138 arelent *r;
2139
2140 if (! info->relocateable)
2141 abort ();
2142 if (sec->orelocation == (arelent **) NULL)
2143 abort ();
2144
2145 r = (arelent *) bfd_alloc (abfd, sizeof (arelent));
2146 if (r == (arelent *) NULL)
2147 {
2148 bfd_set_error (bfd_error_no_memory);
2149 return false;
2150 }
2151
2152 r->address = link_order->offset;
2153 r->howto = bfd_reloc_type_lookup (abfd, link_order->u.reloc.p->reloc);
2154 if (r->howto == (const reloc_howto_type *) NULL)
2155 {
2156 bfd_set_error (bfd_error_bad_value);
2157 return false;
2158 }
2159
2160 /* Get the symbol to use for the relocation. */
2161 if (link_order->type == bfd_section_reloc_link_order)
2162 r->sym_ptr_ptr = link_order->u.reloc.p->u.section->symbol_ptr_ptr;
2163 else
2164 {
2165 struct generic_link_hash_entry *h;
2166
2167 h = _bfd_generic_link_hash_lookup (_bfd_generic_hash_table (info),
2168 link_order->u.reloc.p->u.name,
2169 false, false, true);
2170 if (h == (struct generic_link_hash_entry *) NULL
2171 || ! h->written)
2172 {
2173 if (! ((*info->callbacks->unattached_reloc)
2174 (info, link_order->u.reloc.p->u.name,
2175 (bfd *) NULL, (asection *) NULL, (bfd_vma) 0)))
2176 return false;
2177 bfd_set_error (bfd_error_bad_value);
2178 return false;
2179 }
2180 r->sym_ptr_ptr = &h->sym;
2181 }
2182
2183 /* If this is an inplace reloc, write the addend to the object file.
2184 Otherwise, store it in the reloc addend. */
2185 if (! r->howto->partial_inplace)
2186 r->addend = link_order->u.reloc.p->addend;
2187 else
2188 {
2189 bfd_size_type size;
2190 bfd_reloc_status_type rstat;
2191 bfd_byte *buf;
2192 boolean ok;
2193
2194 size = bfd_get_reloc_size (r->howto);
2195 buf = (bfd_byte *) bfd_zmalloc (size);
2196 if (buf == (bfd_byte *) NULL)
2197 {
2198 bfd_set_error (bfd_error_no_memory);
2199 return false;
2200 }
2201 rstat = _bfd_relocate_contents (r->howto, abfd,
2202 link_order->u.reloc.p->addend, buf);
2203 switch (rstat)
2204 {
2205 case bfd_reloc_ok:
2206 break;
2207 default:
2208 case bfd_reloc_outofrange:
2209 abort ();
2210 case bfd_reloc_overflow:
2211 if (! ((*info->callbacks->reloc_overflow)
2212 (info,
2213 (link_order->type == bfd_section_reloc_link_order
2214 ? bfd_section_name (abfd, link_order->u.reloc.p->u.section)
2215 : link_order->u.reloc.p->u.name),
2216 r->howto->name, link_order->u.reloc.p->addend,
2217 (bfd *) NULL, (asection *) NULL, (bfd_vma) 0)))
2218 {
2219 free (buf);
2220 return false;
2221 }
2222 break;
2223 }
2224 ok = bfd_set_section_contents (abfd, sec, (PTR) buf,
2225 (file_ptr) link_order->offset, size);
2226 free (buf);
2227 if (! ok)
2228 return false;
2229
2230 r->addend = 0;
2231 }
2232
2233 sec->orelocation[sec->reloc_count] = r;
2234 ++sec->reloc_count;
2235
2236 return true;
2237 }
2238 \f
2239 /* Allocate a new link_order for a section. */
2240
2241 struct bfd_link_order *
2242 bfd_new_link_order (abfd, section)
2243 bfd *abfd;
2244 asection *section;
2245 {
2246 struct bfd_link_order *new;
2247
2248 new = ((struct bfd_link_order *)
2249 bfd_alloc_by_size_t (abfd, sizeof (struct bfd_link_order)));
2250 if (!new)
2251 {
2252 bfd_set_error (bfd_error_no_memory);
2253 return NULL;
2254 }
2255
2256 new->type = bfd_undefined_link_order;
2257 new->offset = 0;
2258 new->size = 0;
2259 new->next = (struct bfd_link_order *) NULL;
2260
2261 if (section->link_order_tail != (struct bfd_link_order *) NULL)
2262 section->link_order_tail->next = new;
2263 else
2264 section->link_order_head = new;
2265 section->link_order_tail = new;
2266
2267 return new;
2268 }
2269
2270 /* Default link order processing routine. Note that we can not handle
2271 the reloc_link_order types here, since they depend upon the details
2272 of how the particular backends generates relocs. */
2273
2274 boolean
2275 _bfd_default_link_order (abfd, info, sec, link_order)
2276 bfd *abfd;
2277 struct bfd_link_info *info;
2278 asection *sec;
2279 struct bfd_link_order *link_order;
2280 {
2281 switch (link_order->type)
2282 {
2283 case bfd_undefined_link_order:
2284 case bfd_section_reloc_link_order:
2285 case bfd_symbol_reloc_link_order:
2286 default:
2287 abort ();
2288 case bfd_indirect_link_order:
2289 return default_indirect_link_order (abfd, info, sec, link_order);
2290 case bfd_fill_link_order:
2291 return default_fill_link_order (abfd, info, sec, link_order);
2292 case bfd_data_link_order:
2293 return bfd_set_section_contents (abfd, sec,
2294 (PTR) link_order->u.data.contents,
2295 (file_ptr) link_order->offset,
2296 link_order->size);
2297 }
2298 }
2299
2300 /* Default routine to handle a bfd_fill_link_order. */
2301
2302 /*ARGSUSED*/
2303 static boolean
2304 default_fill_link_order (abfd, info, sec, link_order)
2305 bfd *abfd;
2306 struct bfd_link_info *info;
2307 asection *sec;
2308 struct bfd_link_order *link_order;
2309 {
2310 size_t size;
2311 char *space;
2312 size_t i;
2313 int fill;
2314 boolean result;
2315
2316 BFD_ASSERT ((sec->flags & SEC_HAS_CONTENTS) != 0);
2317
2318 size = (size_t) link_order->size;
2319 space = (char *) malloc (size);
2320 if (space == NULL && size != 0)
2321 {
2322 bfd_set_error (bfd_error_no_memory);
2323 return false;
2324 }
2325
2326 fill = link_order->u.fill.value;
2327 for (i = 0; i < size; i += 2)
2328 space[i] = fill >> 8;
2329 for (i = 1; i < size; i += 2)
2330 space[i] = fill;
2331 result = bfd_set_section_contents (abfd, sec, space,
2332 (file_ptr) link_order->offset,
2333 link_order->size);
2334 free (space);
2335 return result;
2336 }
2337
2338 /* Default routine to handle a bfd_indirect_link_order. */
2339
2340 static boolean
2341 default_indirect_link_order (output_bfd, info, output_section, link_order)
2342 bfd *output_bfd;
2343 struct bfd_link_info *info;
2344 asection *output_section;
2345 struct bfd_link_order *link_order;
2346 {
2347 asection *input_section;
2348 bfd *input_bfd;
2349 bfd_byte *contents = NULL;
2350 bfd_byte *new_contents;
2351
2352 BFD_ASSERT ((output_section->flags & SEC_HAS_CONTENTS) != 0);
2353
2354 if (link_order->size == 0)
2355 return true;
2356
2357 input_section = link_order->u.indirect.section;
2358 input_bfd = input_section->owner;
2359
2360 BFD_ASSERT (input_section->output_section == output_section);
2361 BFD_ASSERT (input_section->output_offset == link_order->offset);
2362 BFD_ASSERT (input_section->_cooked_size == link_order->size);
2363
2364 if (info->relocateable
2365 && input_section->reloc_count > 0
2366 && output_section->orelocation == (arelent **) NULL)
2367 {
2368 /* Space has not been allocated for the output relocations.
2369 This can happen when we are called by a specific backend
2370 because somebody is attempting to link together different
2371 types of object files. Handling this case correctly is
2372 difficult, and sometimes impossible. */
2373 abort ();
2374 }
2375
2376 /* Get the canonical symbols. The generic linker will always have
2377 retrieved them by this point, but we may be being called by a
2378 specific linker when linking different types of object files
2379 together. */
2380 if (! generic_link_read_symbols (input_bfd))
2381 return false;
2382
2383 /* Get and relocate the section contents. */
2384 contents = (bfd_byte *) malloc (bfd_section_size (input_bfd, input_section));
2385 if (contents == NULL && bfd_section_size (input_bfd, input_section) != 0)
2386 {
2387 bfd_set_error (bfd_error_no_memory);
2388 goto error_return;
2389 }
2390 new_contents = (bfd_get_relocated_section_contents
2391 (output_bfd, info, link_order, contents, info->relocateable,
2392 _bfd_generic_link_get_symbols (input_bfd)));
2393 if (!new_contents)
2394 goto error_return;
2395
2396 /* Output the section contents. */
2397 if (! bfd_set_section_contents (output_bfd, output_section,
2398 (PTR) new_contents,
2399 link_order->offset, link_order->size))
2400 goto error_return;
2401
2402 if (contents != NULL)
2403 free (contents);
2404 return true;
2405
2406 error_return:
2407 if (contents != NULL)
2408 free (contents);
2409 return false;
2410 }
2411
2412 /* A little routine to count the number of relocs in a link_order
2413 list. */
2414
2415 unsigned int
2416 _bfd_count_link_order_relocs (link_order)
2417 struct bfd_link_order *link_order;
2418 {
2419 register unsigned int c;
2420 register struct bfd_link_order *l;
2421
2422 c = 0;
2423 for (l = link_order; l != (struct bfd_link_order *) NULL; l = l->next)
2424 {
2425 if (l->type == bfd_section_reloc_link_order
2426 || l->type == bfd_symbol_reloc_link_order)
2427 ++c;
2428 }
2429
2430 return c;
2431 }
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