* targets.c: Add copy_private_symbol_data and link_split_section
[deliverable/binutils-gdb.git] / bfd / linker.c
1 /* linker.c -- BFD linker routines
2 Copyright (C) 1993, 1994, 1995 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.
384
385 The <<strip>> field of the <<bfd_link_info>> structure
386 controls which symbols are written out. The possible values
387 are listed in <<bfdlink.h>>. If the value is <<strip_some>>,
388 then the <<keep_hash>> field of the <<bfd_link_info>>
389 structure is a hash table of symbols to keep; each symbol
390 should be looked up in this hash table, and only symbols which
391 are present should be included in the output file.
392
393 If the <<strip>> field of the <<bfd_link_info>> structure
394 permits local symbols to be written out, the <<discard>> field
395 is used to further controls which local symbols are included
396 in the output file. If the value is <<discard_l>>, then all
397 local symbols which begin with a certain prefix are discarded;
398 this prefix is described by the <<lprefix>> and
399 <<lprefix_len>> fields of the <<bfd_link_info>> structure.
400
401 The a.out backend handles symbols by calling
402 <<aout_link_write_symbols>> on each input BFD and then
403 traversing the global hash table with the function
404 <<aout_link_write_other_symbol>>. It builds a string table
405 while writing out the symbols, which is written to the output
406 file at the end of <<NAME(aout,final_link)>>.
407 */
408
409 static struct bfd_hash_entry *generic_link_hash_newfunc
410 PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *,
411 const char *));
412 static boolean generic_link_read_symbols
413 PARAMS ((bfd *));
414 static boolean generic_link_add_symbols
415 PARAMS ((bfd *, struct bfd_link_info *, boolean collect));
416 static boolean generic_link_add_object_symbols
417 PARAMS ((bfd *, struct bfd_link_info *, boolean collect));
418 static boolean generic_link_check_archive_element_no_collect
419 PARAMS ((bfd *, struct bfd_link_info *, boolean *pneeded));
420 static boolean generic_link_check_archive_element_collect
421 PARAMS ((bfd *, struct bfd_link_info *, boolean *pneeded));
422 static boolean generic_link_check_archive_element
423 PARAMS ((bfd *, struct bfd_link_info *, boolean *pneeded, boolean collect));
424 static boolean generic_link_add_symbol_list
425 PARAMS ((bfd *, struct bfd_link_info *, bfd_size_type count, asymbol **,
426 boolean collect));
427 static void set_symbol_from_hash
428 PARAMS ((asymbol *, struct bfd_link_hash_entry *));
429 static boolean generic_add_output_symbol
430 PARAMS ((bfd *, size_t *psymalloc, asymbol *));
431 static boolean default_fill_link_order
432 PARAMS ((bfd *, struct bfd_link_info *, asection *,
433 struct bfd_link_order *));
434 static boolean default_indirect_link_order
435 PARAMS ((bfd *, struct bfd_link_info *, asection *,
436 struct bfd_link_order *, boolean));
437
438 /* The link hash table structure is defined in bfdlink.h. It provides
439 a base hash table which the backend specific hash tables are built
440 upon. */
441
442 /* Routine to create an entry in the link hash table. */
443
444 struct bfd_hash_entry *
445 _bfd_link_hash_newfunc (entry, table, string)
446 struct bfd_hash_entry *entry;
447 struct bfd_hash_table *table;
448 const char *string;
449 {
450 struct bfd_link_hash_entry *ret = (struct bfd_link_hash_entry *) entry;
451
452 /* Allocate the structure if it has not already been allocated by a
453 subclass. */
454 if (ret == (struct bfd_link_hash_entry *) NULL)
455 ret = ((struct bfd_link_hash_entry *)
456 bfd_hash_allocate (table, sizeof (struct bfd_link_hash_entry)));
457 if (ret == (struct bfd_link_hash_entry *) NULL)
458 {
459 bfd_set_error (bfd_error_no_memory);
460 return NULL;
461 }
462
463 /* Call the allocation method of the superclass. */
464 ret = ((struct bfd_link_hash_entry *)
465 bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));
466
467 if (ret)
468 {
469 /* Initialize the local fields. */
470 ret->type = bfd_link_hash_new;
471 ret->next = NULL;
472 }
473
474 return (struct bfd_hash_entry *) ret;
475 }
476
477 /* Initialize a link hash table. The BFD argument is the one
478 responsible for creating this table. */
479
480 boolean
481 _bfd_link_hash_table_init (table, abfd, newfunc)
482 struct bfd_link_hash_table *table;
483 bfd *abfd;
484 struct bfd_hash_entry *(*newfunc) PARAMS ((struct bfd_hash_entry *,
485 struct bfd_hash_table *,
486 const char *));
487 {
488 table->creator = abfd->xvec;
489 table->undefs = NULL;
490 table->undefs_tail = NULL;
491 return bfd_hash_table_init (&table->table, newfunc);
492 }
493
494 /* Look up a symbol in a link hash table. If follow is true, we
495 follow bfd_link_hash_indirect and bfd_link_hash_warning links to
496 the real symbol. */
497
498 struct bfd_link_hash_entry *
499 bfd_link_hash_lookup (table, string, create, copy, follow)
500 struct bfd_link_hash_table *table;
501 const char *string;
502 boolean create;
503 boolean copy;
504 boolean follow;
505 {
506 struct bfd_link_hash_entry *ret;
507
508 ret = ((struct bfd_link_hash_entry *)
509 bfd_hash_lookup (&table->table, string, create, copy));
510
511 if (follow && ret != (struct bfd_link_hash_entry *) NULL)
512 {
513 while (ret->type == bfd_link_hash_indirect
514 || ret->type == bfd_link_hash_warning)
515 ret = ret->u.i.link;
516 }
517
518 return ret;
519 }
520
521 /* Traverse a generic link hash table. The only reason this is not a
522 macro is to do better type checking. This code presumes that an
523 argument passed as a struct bfd_hash_entry * may be caught as a
524 struct bfd_link_hash_entry * with no explicit cast required on the
525 call. */
526
527 void
528 bfd_link_hash_traverse (table, func, info)
529 struct bfd_link_hash_table *table;
530 boolean (*func) PARAMS ((struct bfd_link_hash_entry *, PTR));
531 PTR info;
532 {
533 bfd_hash_traverse (&table->table,
534 ((boolean (*) PARAMS ((struct bfd_hash_entry *, PTR)))
535 func),
536 info);
537 }
538
539 /* Add a symbol to the linker hash table undefs list. */
540
541 INLINE void
542 bfd_link_add_undef (table, h)
543 struct bfd_link_hash_table *table;
544 struct bfd_link_hash_entry *h;
545 {
546 BFD_ASSERT (h->next == NULL);
547 if (table->undefs_tail != (struct bfd_link_hash_entry *) NULL)
548 table->undefs_tail->next = h;
549 if (table->undefs == (struct bfd_link_hash_entry *) NULL)
550 table->undefs = h;
551 table->undefs_tail = h;
552 }
553 \f
554 /* Routine to create an entry in an generic link hash table. */
555
556 static struct bfd_hash_entry *
557 generic_link_hash_newfunc (entry, table, string)
558 struct bfd_hash_entry *entry;
559 struct bfd_hash_table *table;
560 const char *string;
561 {
562 struct generic_link_hash_entry *ret =
563 (struct generic_link_hash_entry *) entry;
564
565 /* Allocate the structure if it has not already been allocated by a
566 subclass. */
567 if (ret == (struct generic_link_hash_entry *) NULL)
568 ret = ((struct generic_link_hash_entry *)
569 bfd_hash_allocate (table, sizeof (struct generic_link_hash_entry)));
570 if (ret == (struct generic_link_hash_entry *) NULL)
571 {
572 bfd_set_error (bfd_error_no_memory);
573 return NULL;
574 }
575
576 /* Call the allocation method of the superclass. */
577 ret = ((struct generic_link_hash_entry *)
578 _bfd_link_hash_newfunc ((struct bfd_hash_entry *) ret,
579 table, string));
580
581 if (ret)
582 {
583 /* Set local fields. */
584 ret->written = false;
585 ret->sym = NULL;
586 }
587
588 return (struct bfd_hash_entry *) ret;
589 }
590
591 /* Create an generic link hash table. */
592
593 struct bfd_link_hash_table *
594 _bfd_generic_link_hash_table_create (abfd)
595 bfd *abfd;
596 {
597 struct generic_link_hash_table *ret;
598
599 ret = ((struct generic_link_hash_table *)
600 malloc (sizeof (struct generic_link_hash_table)));
601 if (!ret)
602 {
603 bfd_set_error (bfd_error_no_memory);
604 return (struct bfd_link_hash_table *) NULL;
605 }
606 if (! _bfd_link_hash_table_init (&ret->root, abfd,
607 generic_link_hash_newfunc))
608 {
609 free (ret);
610 return (struct bfd_link_hash_table *) NULL;
611 }
612 return &ret->root;
613 }
614
615 /* Grab the symbols for an object file when doing a generic link. We
616 store the symbols in the outsymbols field. We need to keep them
617 around for the entire link to ensure that we only read them once.
618 If we read them multiple times, we might wind up with relocs and
619 the hash table pointing to different instances of the symbol
620 structure. */
621
622 static boolean
623 generic_link_read_symbols (abfd)
624 bfd *abfd;
625 {
626 if (abfd->outsymbols == (asymbol **) NULL)
627 {
628 long symsize;
629 long symcount;
630
631 symsize = bfd_get_symtab_upper_bound (abfd);
632 if (symsize < 0)
633 return false;
634 abfd->outsymbols = (asymbol **) bfd_alloc (abfd, symsize);
635 if (abfd->outsymbols == NULL && symsize != 0)
636 {
637 bfd_set_error (bfd_error_no_memory);
638 return false;
639 }
640 symcount = bfd_canonicalize_symtab (abfd, abfd->outsymbols);
641 if (symcount < 0)
642 return false;
643 abfd->symcount = symcount;
644 }
645
646 return true;
647 }
648 \f
649 /* Generic function to add symbols to from an object file to the
650 global hash table. This version does not automatically collect
651 constructors by name. */
652
653 boolean
654 _bfd_generic_link_add_symbols (abfd, info)
655 bfd *abfd;
656 struct bfd_link_info *info;
657 {
658 return generic_link_add_symbols (abfd, info, false);
659 }
660
661 /* Generic function to add symbols from an object file to the global
662 hash table. This version automatically collects constructors by
663 name, as the collect2 program does. It should be used for any
664 target which does not provide some other mechanism for setting up
665 constructors and destructors; these are approximately those targets
666 for which gcc uses collect2 and do not support stabs. */
667
668 boolean
669 _bfd_generic_link_add_symbols_collect (abfd, info)
670 bfd *abfd;
671 struct bfd_link_info *info;
672 {
673 return generic_link_add_symbols (abfd, info, true);
674 }
675
676 /* Add symbols from an object file to the global hash table. */
677
678 static boolean
679 generic_link_add_symbols (abfd, info, collect)
680 bfd *abfd;
681 struct bfd_link_info *info;
682 boolean collect;
683 {
684 boolean ret;
685
686 switch (bfd_get_format (abfd))
687 {
688 case bfd_object:
689 ret = generic_link_add_object_symbols (abfd, info, collect);
690 break;
691 case bfd_archive:
692 ret = (_bfd_generic_link_add_archive_symbols
693 (abfd, info,
694 (collect
695 ? generic_link_check_archive_element_collect
696 : generic_link_check_archive_element_no_collect)));
697 break;
698 default:
699 bfd_set_error (bfd_error_wrong_format);
700 ret = false;
701 }
702
703 return ret;
704 }
705
706 /* Add symbols from an object file to the global hash table. */
707
708 static boolean
709 generic_link_add_object_symbols (abfd, info, collect)
710 bfd *abfd;
711 struct bfd_link_info *info;
712 boolean collect;
713 {
714 if (! generic_link_read_symbols (abfd))
715 return false;
716 return generic_link_add_symbol_list (abfd, info,
717 _bfd_generic_link_get_symcount (abfd),
718 _bfd_generic_link_get_symbols (abfd),
719 collect);
720 }
721 \f
722 /* We build a hash table of all symbols defined in an archive. */
723
724 /* An archive symbol may be defined by multiple archive elements.
725 This linked list is used to hold the elements. */
726
727 struct archive_list
728 {
729 struct archive_list *next;
730 int indx;
731 };
732
733 /* An entry in an archive hash table. */
734
735 struct archive_hash_entry
736 {
737 struct bfd_hash_entry root;
738 /* Where the symbol is defined. */
739 struct archive_list *defs;
740 };
741
742 /* An archive hash table itself. */
743
744 struct archive_hash_table
745 {
746 struct bfd_hash_table table;
747 };
748
749 static struct bfd_hash_entry *archive_hash_newfunc
750 PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *));
751 static boolean archive_hash_table_init
752 PARAMS ((struct archive_hash_table *,
753 struct bfd_hash_entry *(*) (struct bfd_hash_entry *,
754 struct bfd_hash_table *,
755 const char *)));
756
757 /* Create a new entry for an archive hash table. */
758
759 static struct bfd_hash_entry *
760 archive_hash_newfunc (entry, table, string)
761 struct bfd_hash_entry *entry;
762 struct bfd_hash_table *table;
763 const char *string;
764 {
765 struct archive_hash_entry *ret = (struct archive_hash_entry *) entry;
766
767 /* Allocate the structure if it has not already been allocated by a
768 subclass. */
769 if (ret == (struct archive_hash_entry *) NULL)
770 ret = ((struct archive_hash_entry *)
771 bfd_hash_allocate (table, sizeof (struct archive_hash_entry)));
772 if (ret == (struct archive_hash_entry *) NULL)
773 {
774 bfd_set_error (bfd_error_no_memory);
775 return NULL;
776 }
777
778 /* Call the allocation method of the superclass. */
779 ret = ((struct archive_hash_entry *)
780 bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));
781
782 if (ret)
783 {
784 /* Initialize the local fields. */
785 ret->defs = (struct archive_list *) NULL;
786 }
787
788 return (struct bfd_hash_entry *) ret;
789 }
790
791 /* Initialize an archive hash table. */
792
793 static boolean
794 archive_hash_table_init (table, newfunc)
795 struct archive_hash_table *table;
796 struct bfd_hash_entry *(*newfunc) PARAMS ((struct bfd_hash_entry *,
797 struct bfd_hash_table *,
798 const char *));
799 {
800 return bfd_hash_table_init (&table->table, newfunc);
801 }
802
803 /* Look up an entry in an archive hash table. */
804
805 #define archive_hash_lookup(t, string, create, copy) \
806 ((struct archive_hash_entry *) \
807 bfd_hash_lookup (&(t)->table, (string), (create), (copy)))
808
809 /* Allocate space in an archive hash table. */
810
811 #define archive_hash_allocate(t, size) bfd_hash_allocate (&(t)->table, (size))
812
813 /* Free an archive hash table. */
814
815 #define archive_hash_table_free(t) bfd_hash_table_free (&(t)->table)
816
817 /* Generic function to add symbols from an archive file to the global
818 hash file. This function presumes that the archive symbol table
819 has already been read in (this is normally done by the
820 bfd_check_format entry point). It looks through the undefined and
821 common symbols and searches the archive symbol table for them. If
822 it finds an entry, it includes the associated object file in the
823 link.
824
825 The old linker looked through the archive symbol table for
826 undefined symbols. We do it the other way around, looking through
827 undefined symbols for symbols defined in the archive. The
828 advantage of the newer scheme is that we only have to look through
829 the list of undefined symbols once, whereas the old method had to
830 re-search the symbol table each time a new object file was added.
831
832 The CHECKFN argument is used to see if an object file should be
833 included. CHECKFN should set *PNEEDED to true if the object file
834 should be included, and must also call the bfd_link_info
835 add_archive_element callback function and handle adding the symbols
836 to the global hash table. CHECKFN should only return false if some
837 sort of error occurs.
838
839 For some formats, such as a.out, it is possible to look through an
840 object file but not actually include it in the link. The
841 archive_pass field in a BFD is used to avoid checking the symbols
842 of an object files too many times. When an object is included in
843 the link, archive_pass is set to -1. If an object is scanned but
844 not included, archive_pass is set to the pass number. The pass
845 number is incremented each time a new object file is included. The
846 pass number is used because when a new object file is included it
847 may create new undefined symbols which cause a previously examined
848 object file to be included. */
849
850 boolean
851 _bfd_generic_link_add_archive_symbols (abfd, info, checkfn)
852 bfd *abfd;
853 struct bfd_link_info *info;
854 boolean (*checkfn) PARAMS ((bfd *, struct bfd_link_info *,
855 boolean *pneeded));
856 {
857 carsym *arsyms;
858 carsym *arsym_end;
859 register carsym *arsym;
860 int pass;
861 struct archive_hash_table arsym_hash;
862 int indx;
863 struct bfd_link_hash_entry **pundef;
864
865 if (! bfd_has_map (abfd))
866 {
867 /* An empty archive is a special case. */
868 if (bfd_openr_next_archived_file (abfd, (bfd *) NULL) == NULL)
869 return true;
870 bfd_set_error (bfd_error_no_symbols);
871 return false;
872 }
873
874 arsyms = bfd_ardata (abfd)->symdefs;
875 arsym_end = arsyms + bfd_ardata (abfd)->symdef_count;
876
877 /* In order to quickly determine whether an symbol is defined in
878 this archive, we build a hash table of the symbols. */
879 if (! archive_hash_table_init (&arsym_hash, archive_hash_newfunc))
880 return false;
881 for (arsym = arsyms, indx = 0; arsym < arsym_end; arsym++, indx++)
882 {
883 struct archive_hash_entry *arh;
884 struct archive_list *l, **pp;
885
886 arh = archive_hash_lookup (&arsym_hash, arsym->name, true, false);
887 if (arh == (struct archive_hash_entry *) NULL)
888 goto error_return;
889 l = ((struct archive_list *)
890 archive_hash_allocate (&arsym_hash, sizeof (struct archive_list)));
891 if (l == NULL)
892 goto error_return;
893 l->indx = indx;
894 for (pp = &arh->defs;
895 *pp != (struct archive_list *) NULL;
896 pp = &(*pp)->next)
897 ;
898 *pp = l;
899 l->next = NULL;
900 }
901
902 /* The archive_pass field in the archive itself is used to
903 initialize PASS, sine we may search the same archive multiple
904 times. */
905 pass = abfd->archive_pass + 1;
906
907 /* New undefined symbols are added to the end of the list, so we
908 only need to look through it once. */
909 pundef = &info->hash->undefs;
910 while (*pundef != (struct bfd_link_hash_entry *) NULL)
911 {
912 struct bfd_link_hash_entry *h;
913 struct archive_hash_entry *arh;
914 struct archive_list *l;
915
916 h = *pundef;
917
918 /* When a symbol is defined, it is not necessarily removed from
919 the list. */
920 if (h->type != bfd_link_hash_undefined
921 && h->type != bfd_link_hash_common)
922 {
923 /* Remove this entry from the list, for general cleanliness
924 and because we are going to look through the list again
925 if we search any more libraries. We can't remove the
926 entry if it is the tail, because that would lose any
927 entries we add to the list later on (it would also cause
928 us to lose track of whether the symbol has been
929 referenced). */
930 if (*pundef != info->hash->undefs_tail)
931 *pundef = (*pundef)->next;
932 else
933 pundef = &(*pundef)->next;
934 continue;
935 }
936
937 /* Look for this symbol in the archive symbol map. */
938 arh = archive_hash_lookup (&arsym_hash, h->root.string, false, false);
939 if (arh == (struct archive_hash_entry *) NULL)
940 {
941 pundef = &(*pundef)->next;
942 continue;
943 }
944
945 /* Look at all the objects which define this symbol. */
946 for (l = arh->defs; l != (struct archive_list *) NULL; l = l->next)
947 {
948 bfd *element;
949 boolean needed;
950
951 /* If the symbol has gotten defined along the way, quit. */
952 if (h->type != bfd_link_hash_undefined
953 && h->type != bfd_link_hash_common)
954 break;
955
956 element = bfd_get_elt_at_index (abfd, l->indx);
957 if (element == (bfd *) NULL)
958 goto error_return;
959
960 /* If we've already included this element, or if we've
961 already checked it on this pass, continue. */
962 if (element->archive_pass == -1
963 || element->archive_pass == pass)
964 continue;
965
966 /* If we can't figure this element out, just ignore it. */
967 if (! bfd_check_format (element, bfd_object))
968 {
969 element->archive_pass = -1;
970 continue;
971 }
972
973 /* CHECKFN will see if this element should be included, and
974 go ahead and include it if appropriate. */
975 if (! (*checkfn) (element, info, &needed))
976 goto error_return;
977
978 if (! needed)
979 element->archive_pass = pass;
980 else
981 {
982 element->archive_pass = -1;
983
984 /* Increment the pass count to show that we may need to
985 recheck object files which were already checked. */
986 ++pass;
987 }
988 }
989
990 pundef = &(*pundef)->next;
991 }
992
993 archive_hash_table_free (&arsym_hash);
994
995 /* Save PASS in case we are called again. */
996 abfd->archive_pass = pass;
997
998 return true;
999
1000 error_return:
1001 archive_hash_table_free (&arsym_hash);
1002 return false;
1003 }
1004 \f
1005 /* See if we should include an archive element. This version is used
1006 when we do not want to automatically collect constructors based on
1007 the symbol name, presumably because we have some other mechanism
1008 for finding them. */
1009
1010 static boolean
1011 generic_link_check_archive_element_no_collect (abfd, info, pneeded)
1012 bfd *abfd;
1013 struct bfd_link_info *info;
1014 boolean *pneeded;
1015 {
1016 return generic_link_check_archive_element (abfd, info, pneeded, false);
1017 }
1018
1019 /* See if we should include an archive element. This version is used
1020 when we want to automatically collect constructors based on the
1021 symbol name, as collect2 does. */
1022
1023 static boolean
1024 generic_link_check_archive_element_collect (abfd, info, pneeded)
1025 bfd *abfd;
1026 struct bfd_link_info *info;
1027 boolean *pneeded;
1028 {
1029 return generic_link_check_archive_element (abfd, info, pneeded, true);
1030 }
1031
1032 /* See if we should include an archive element. Optionally collect
1033 constructors. */
1034
1035 static boolean
1036 generic_link_check_archive_element (abfd, info, pneeded, collect)
1037 bfd *abfd;
1038 struct bfd_link_info *info;
1039 boolean *pneeded;
1040 boolean collect;
1041 {
1042 asymbol **pp, **ppend;
1043
1044 *pneeded = false;
1045
1046 if (! generic_link_read_symbols (abfd))
1047 return false;
1048
1049 pp = _bfd_generic_link_get_symbols (abfd);
1050 ppend = pp + _bfd_generic_link_get_symcount (abfd);
1051 for (; pp < ppend; pp++)
1052 {
1053 asymbol *p;
1054 struct bfd_link_hash_entry *h;
1055
1056 p = *pp;
1057
1058 /* We are only interested in globally visible symbols. */
1059 if (! bfd_is_com_section (p->section)
1060 && (p->flags & (BSF_GLOBAL | BSF_INDIRECT | BSF_WEAK)) == 0)
1061 continue;
1062
1063 /* We are only interested if we know something about this
1064 symbol, and it is undefined or common. An undefined weak
1065 symbol (type bfd_link_hash_undefweak) is not considered to be
1066 a reference when pulling files out of an archive. See the
1067 SVR4 ABI, p. 4-27. */
1068 h = bfd_link_hash_lookup (info->hash, bfd_asymbol_name (p), false,
1069 false, true);
1070 if (h == (struct bfd_link_hash_entry *) NULL
1071 || (h->type != bfd_link_hash_undefined
1072 && h->type != bfd_link_hash_common))
1073 continue;
1074
1075 /* P is a symbol we are looking for. */
1076
1077 if (! bfd_is_com_section (p->section))
1078 {
1079 bfd_size_type symcount;
1080 asymbol **symbols;
1081
1082 /* This object file defines this symbol, so pull it in. */
1083 if (! (*info->callbacks->add_archive_element) (info, abfd,
1084 bfd_asymbol_name (p)))
1085 return false;
1086 symcount = _bfd_generic_link_get_symcount (abfd);
1087 symbols = _bfd_generic_link_get_symbols (abfd);
1088 if (! generic_link_add_symbol_list (abfd, info, symcount,
1089 symbols, collect))
1090 return false;
1091 *pneeded = true;
1092 return true;
1093 }
1094
1095 /* P is a common symbol. */
1096
1097 if (h->type == bfd_link_hash_undefined)
1098 {
1099 bfd *symbfd;
1100 bfd_vma size;
1101 unsigned int power;
1102
1103 symbfd = h->u.undef.abfd;
1104 if (symbfd == (bfd *) NULL)
1105 {
1106 /* This symbol was created as undefined from outside
1107 BFD. We assume that we should link in the object
1108 file. This is for the -u option in the linker. */
1109 if (! (*info->callbacks->add_archive_element)
1110 (info, abfd, bfd_asymbol_name (p)))
1111 return false;
1112 *pneeded = true;
1113 return true;
1114 }
1115
1116 /* Turn the symbol into a common symbol but do not link in
1117 the object file. This is how a.out works. Object
1118 formats that require different semantics must implement
1119 this function differently. This symbol is already on the
1120 undefs list. We add the section to a common section
1121 attached to symbfd to ensure that it is in a BFD which
1122 will be linked in. */
1123 h->type = bfd_link_hash_common;
1124
1125 size = bfd_asymbol_value (p);
1126 h->u.c.size = size;
1127 if (h->u.c.size != size)
1128 {
1129 /* The size did not fit in the bitfield. */
1130 bfd_set_error (bfd_error_bad_value);
1131 return false;
1132 }
1133
1134 power = bfd_log2 (size);
1135 if (power > 4)
1136 power = 4;
1137 h->u.c.alignment_power = power;
1138
1139 if (p->section == bfd_com_section_ptr)
1140 h->u.c.section = bfd_make_section_old_way (symbfd, "COMMON");
1141 else
1142 h->u.c.section = bfd_make_section_old_way (symbfd,
1143 p->section->name);
1144 h->u.c.section->flags = SEC_ALLOC;
1145 }
1146 else
1147 {
1148 /* Adjust the size of the common symbol if necessary. This
1149 is how a.out works. Object formats that require
1150 different semantics must implement this function
1151 differently. */
1152 if (bfd_asymbol_value (p) > h->u.c.size)
1153 h->u.c.size = bfd_asymbol_value (p);
1154 }
1155 }
1156
1157 /* This archive element is not needed. */
1158 return true;
1159 }
1160
1161 /* Add the symbols from an object file to the global hash table. ABFD
1162 is the object file. INFO is the linker information. SYMBOL_COUNT
1163 is the number of symbols. SYMBOLS is the list of symbols. COLLECT
1164 is true if constructors should be automatically collected by name
1165 as is done by collect2. */
1166
1167 static boolean
1168 generic_link_add_symbol_list (abfd, info, symbol_count, symbols, collect)
1169 bfd *abfd;
1170 struct bfd_link_info *info;
1171 bfd_size_type symbol_count;
1172 asymbol **symbols;
1173 boolean collect;
1174 {
1175 asymbol **pp, **ppend;
1176
1177 pp = symbols;
1178 ppend = symbols + symbol_count;
1179 for (; pp < ppend; pp++)
1180 {
1181 asymbol *p;
1182
1183 p = *pp;
1184
1185 if ((p->flags & (BSF_INDIRECT
1186 | BSF_WARNING
1187 | BSF_GLOBAL
1188 | BSF_CONSTRUCTOR
1189 | BSF_WEAK)) != 0
1190 || bfd_is_und_section (bfd_get_section (p))
1191 || bfd_is_com_section (bfd_get_section (p))
1192 || bfd_is_ind_section (bfd_get_section (p)))
1193 {
1194 const char *name;
1195 const char *string;
1196 struct generic_link_hash_entry *h;
1197
1198 name = bfd_asymbol_name (p);
1199 if ((p->flags & BSF_INDIRECT) != 0
1200 || bfd_is_ind_section (p->section))
1201 string = bfd_asymbol_name ((asymbol *) p->value);
1202 else if ((p->flags & BSF_WARNING) != 0)
1203 {
1204 /* The name of P is actually the warning string, and the
1205 value is actually a pointer to the symbol to warn
1206 about. */
1207 string = name;
1208 name = bfd_asymbol_name ((asymbol *) p->value);
1209 }
1210 else
1211 string = NULL;
1212
1213 h = NULL;
1214 if (! (_bfd_generic_link_add_one_symbol
1215 (info, abfd, name, p->flags, bfd_get_section (p),
1216 p->value, string, false, collect,
1217 (struct bfd_link_hash_entry **) &h)))
1218 return false;
1219
1220 /* Save the BFD symbol so that we don't lose any backend
1221 specific information that may be attached to it. We only
1222 want this one if it gives more information than the
1223 existing one; we don't want to replace a defined symbol
1224 with an undefined one. This routine may be called with a
1225 hash table other than the generic hash table, so we only
1226 do this if we are certain that the hash table is a
1227 generic one. */
1228 if (info->hash->creator == abfd->xvec)
1229 {
1230 if (h->sym == (asymbol *) NULL
1231 || (! bfd_is_und_section (bfd_get_section (p))
1232 && (! bfd_is_com_section (bfd_get_section (p))
1233 || bfd_is_und_section (bfd_get_section (h->sym)))))
1234 {
1235 h->sym = p;
1236 /* BSF_OLD_COMMON is a hack to support COFF reloc
1237 reading, and it should go away when the COFF
1238 linker is switched to the new version. */
1239 if (bfd_is_com_section (bfd_get_section (p)))
1240 p->flags |= BSF_OLD_COMMON;
1241 }
1242
1243 /* Store a back pointer from the symbol to the hash
1244 table entry for the benefit of relaxation code until
1245 it gets rewritten to not use asymbol structures.
1246 Setting this is also used to check whether these
1247 symbols were set up by the generic linker. */
1248 p->udata.p = (PTR) h;
1249 }
1250 }
1251 }
1252
1253 return true;
1254 }
1255 \f
1256 /* We use a state table to deal with adding symbols from an object
1257 file. The first index into the state table describes the symbol
1258 from the object file. The second index into the state table is the
1259 type of the symbol in the hash table. */
1260
1261 /* The symbol from the object file is turned into one of these row
1262 values. */
1263
1264 enum link_row
1265 {
1266 UNDEF_ROW, /* Undefined. */
1267 UNDEFW_ROW, /* Weak undefined. */
1268 DEF_ROW, /* Defined. */
1269 DEFW_ROW, /* Weak defined. */
1270 COMMON_ROW, /* Common. */
1271 INDR_ROW, /* Indirect. */
1272 WARN_ROW, /* Warning. */
1273 SET_ROW /* Member of set. */
1274 };
1275
1276 /* apparently needed for Hitachi 3050R(HI-UX/WE2)? */
1277 #undef FAIL
1278
1279 /* The actions to take in the state table. */
1280
1281 enum link_action
1282 {
1283 FAIL, /* Abort. */
1284 UND, /* Mark symbol undefined. */
1285 WEAK, /* Mark symbol weak undefined. */
1286 DEF, /* Mark symbol defined. */
1287 DEFW, /* Mark symbol weak defined. */
1288 COM, /* Mark symbol common. */
1289 REF, /* Mark defined symbol referenced. */
1290 CREF, /* Possibly warn about common reference to defined symbol. */
1291 CDEF, /* Define existing common symbol. */
1292 NOACT, /* No action. */
1293 BIG, /* Mark symbol common using largest size. */
1294 MDEF, /* Multiple definition error. */
1295 MIND, /* Multiple indirect symbols. */
1296 IND, /* Make indirect symbol. */
1297 CIND, /* Make indirect symbol from existing common symbol. */
1298 SET, /* Add value to set. */
1299 MWARN, /* Make warning symbol. */
1300 WARN, /* Issue warning. */
1301 CWARN, /* Warn if referenced, else MWARN. */
1302 CYCLE, /* Repeat with symbol pointed to. */
1303 REFC, /* Mark indirect symbol referenced and then CYCLE. */
1304 WARNC /* Issue warning and then CYCLE. */
1305 };
1306
1307 /* The state table itself. The first index is a link_row and the
1308 second index is a bfd_link_hash_type. */
1309
1310 static const enum link_action link_action[8][8] =
1311 {
1312 /* current\prev new undef undefw def defw com indr warn */
1313 /* UNDEF_ROW */ {UND, NOACT, NOACT, REF, REF, NOACT, REFC, WARNC },
1314 /* UNDEFW_ROW */ {WEAK, WEAK, NOACT, REF, REF, NOACT, REFC, WARNC },
1315 /* DEF_ROW */ {DEF, DEF, DEF, MDEF, DEF, CDEF, MDEF, CYCLE },
1316 /* DEFW_ROW */ {DEFW, DEFW, DEFW, NOACT, NOACT, NOACT, NOACT, CYCLE },
1317 /* COMMON_ROW */ {COM, COM, COM, CREF, CREF, BIG, CREF, WARNC },
1318 /* INDR_ROW */ {IND, IND, IND, MDEF, IND, CIND, MIND, CYCLE },
1319 /* WARN_ROW */ {MWARN, WARN, WARN, CWARN, CWARN, WARN, CWARN, CYCLE },
1320 /* SET_ROW */ {SET, SET, SET, SET, SET, SET, CYCLE, CYCLE }
1321 };
1322
1323 /* Most of the entries in the LINK_ACTION table are straightforward,
1324 but a few are somewhat subtle.
1325
1326 A reference to an indirect symbol (UNDEF_ROW/indr or
1327 UNDEFW_ROW/indr) is counted as a reference both to the indirect
1328 symbol and to the symbol the indirect symbol points to.
1329
1330 A reference to a warning symbol (UNDEF_ROW/warn or UNDEFW_ROW/warn)
1331 causes the warning to be issued.
1332
1333 A common definition of an indirect symbol (COMMON_ROW/indr) is
1334 treated as a multiple definition error. Likewise for an indirect
1335 definition of a common symbol (INDR_ROW/com).
1336
1337 An indirect definition of a warning (INDR_ROW/warn) does not cause
1338 the warning to be issued.
1339
1340 If a warning is created for an indirect symbol (WARN_ROW/indr) no
1341 warning is created for the symbol the indirect symbol points to.
1342
1343 Adding an entry to a set does not count as a reference to a set,
1344 and no warning is issued (SET_ROW/warn). */
1345
1346 /* Add a symbol to the global hash table.
1347 ABFD is the BFD the symbol comes from.
1348 NAME is the name of the symbol.
1349 FLAGS is the BSF_* bits associated with the symbol.
1350 SECTION is the section in which the symbol is defined; this may be
1351 bfd_und_section_ptr or bfd_com_section_ptr.
1352 VALUE is the value of the symbol, relative to the section.
1353 STRING is used for either an indirect symbol, in which case it is
1354 the name of the symbol to indirect to, or a warning symbol, in
1355 which case it is the warning string.
1356 COPY is true if NAME or STRING must be copied into locally
1357 allocated memory if they need to be saved.
1358 COLLECT is true if we should automatically collect gcc constructor
1359 or destructor names as collect2 does.
1360 HASHP, if not NULL, is a place to store the created hash table
1361 entry; if *HASHP is not NULL, the caller has already looked up
1362 the hash table entry, and stored it in *HASHP. */
1363
1364 boolean
1365 _bfd_generic_link_add_one_symbol (info, abfd, name, flags, section, value,
1366 string, copy, collect, hashp)
1367 struct bfd_link_info *info;
1368 bfd *abfd;
1369 const char *name;
1370 flagword flags;
1371 asection *section;
1372 bfd_vma value;
1373 const char *string;
1374 boolean copy;
1375 boolean collect;
1376 struct bfd_link_hash_entry **hashp;
1377 {
1378 enum link_row row;
1379 struct bfd_link_hash_entry *h;
1380 boolean cycle;
1381
1382 if (bfd_is_ind_section (section)
1383 || (flags & BSF_INDIRECT) != 0)
1384 row = INDR_ROW;
1385 else if ((flags & BSF_WARNING) != 0)
1386 row = WARN_ROW;
1387 else if ((flags & BSF_CONSTRUCTOR) != 0)
1388 row = SET_ROW;
1389 else if (bfd_is_und_section (section))
1390 {
1391 if ((flags & BSF_WEAK) != 0)
1392 row = UNDEFW_ROW;
1393 else
1394 row = UNDEF_ROW;
1395 }
1396 else if ((flags & BSF_WEAK) != 0)
1397 row = DEFW_ROW;
1398 else if (bfd_is_com_section (section))
1399 row = COMMON_ROW;
1400 else
1401 row = DEF_ROW;
1402
1403 if (hashp != NULL && *hashp != NULL)
1404 {
1405 h = *hashp;
1406 BFD_ASSERT (strcmp (h->root.string, name) == 0);
1407 }
1408 else
1409 {
1410 h = bfd_link_hash_lookup (info->hash, name, true, copy, false);
1411 if (h == NULL)
1412 {
1413 if (hashp != NULL)
1414 *hashp = NULL;
1415 return false;
1416 }
1417 }
1418
1419 if (info->notice_hash != (struct bfd_hash_table *) NULL
1420 && (bfd_hash_lookup (info->notice_hash, name, false, false)
1421 != (struct bfd_hash_entry *) NULL))
1422 {
1423 if (! (*info->callbacks->notice) (info, name, abfd, section, value))
1424 return false;
1425 }
1426
1427 if (hashp != (struct bfd_link_hash_entry **) NULL)
1428 *hashp = h;
1429
1430 do
1431 {
1432 enum link_action action;
1433
1434 cycle = false;
1435 action = link_action[(int) row][(int) h->type];
1436 switch (action)
1437 {
1438 case FAIL:
1439 abort ();
1440
1441 case NOACT:
1442 /* Do nothing. */
1443 break;
1444
1445 case UND:
1446 /* Make a new undefined symbol. */
1447 h->type = bfd_link_hash_undefined;
1448 h->u.undef.abfd = abfd;
1449 bfd_link_add_undef (info->hash, h);
1450 break;
1451
1452 case WEAK:
1453 /* Make a new weak undefined symbol. */
1454 h->type = bfd_link_hash_undefweak;
1455 h->u.undef.abfd = abfd;
1456 break;
1457
1458 case CDEF:
1459 /* We have found a definition for a symbol which was
1460 previously common. */
1461 BFD_ASSERT (h->type == bfd_link_hash_common);
1462 if (! ((*info->callbacks->multiple_common)
1463 (info, name,
1464 h->u.c.section->owner, bfd_link_hash_common, h->u.c.size,
1465 abfd, bfd_link_hash_defined, (bfd_vma) 0)))
1466 return false;
1467 /* Fall through. */
1468 case DEF:
1469 case DEFW:
1470 {
1471 enum bfd_link_order_type oldtype;
1472
1473 /* Define a symbol. */
1474 oldtype = h->type;
1475 if (action == DEFW)
1476 h->type = bfd_link_hash_defweak;
1477 else
1478 h->type = bfd_link_hash_defined;
1479 h->u.def.section = section;
1480 h->u.def.value = value;
1481
1482 /* If we have been asked to, we act like collect2 and
1483 identify all functions that might be global
1484 constructors and destructors and pass them up in a
1485 callback. We only do this for certain object file
1486 types, since many object file types can handle this
1487 automatically. */
1488 if (collect && name[0] == '_')
1489 {
1490 const char *s;
1491
1492 /* A constructor or destructor name starts like this:
1493 _+GLOBAL_[_.$][ID][_.$] where the first [_.$] and
1494 the second are the same character (we accept any
1495 character there, in case a new object file format
1496 comes along with even worse naming restrictions). */
1497
1498 #define CONS_PREFIX "GLOBAL_"
1499 #define CONS_PREFIX_LEN (sizeof CONS_PREFIX - 1)
1500
1501 s = name + 1;
1502 while (*s == '_')
1503 ++s;
1504 if (s[0] == 'G'
1505 && strncmp (s, CONS_PREFIX, CONS_PREFIX_LEN - 1) == 0)
1506 {
1507 char c;
1508
1509 c = s[CONS_PREFIX_LEN + 1];
1510 if ((c == 'I' || c == 'D')
1511 && s[CONS_PREFIX_LEN] == s[CONS_PREFIX_LEN + 2])
1512 {
1513 /* If this is a definition of a symbol which
1514 was previously weakly defined, we are in
1515 trouble. We have already added a
1516 constructor entry for the weak defined
1517 symbol, and now we are trying to add one
1518 for the new symbol. Fortunately, this case
1519 should never arise in practice. */
1520 if (oldtype == bfd_link_hash_defweak)
1521 abort ();
1522
1523 if (! ((*info->callbacks->constructor)
1524 (info,
1525 c == 'I' ? true : false,
1526 name, abfd, section, value)))
1527 return false;
1528 }
1529 }
1530 }
1531 }
1532
1533 break;
1534
1535 case COM:
1536 /* We have found a common definition for a symbol. */
1537 if (h->type == bfd_link_hash_new)
1538 bfd_link_add_undef (info->hash, h);
1539 h->type = bfd_link_hash_common;
1540 h->u.c.size = value;
1541 if (h->u.c.size != value)
1542 {
1543 /* The size did not fit in the bitfield. */
1544 bfd_set_error (bfd_error_bad_value);
1545 return false;
1546 }
1547
1548 /* Select a default alignment based on the size. This may
1549 be overridden by the caller. */
1550 {
1551 unsigned int power;
1552
1553 power = bfd_log2 (value);
1554 if (power > 4)
1555 power = 4;
1556 h->u.c.alignment_power = power;
1557 }
1558
1559 /* The section of a common symbol is only used if the common
1560 symbol is actually allocated. It basically provides a
1561 hook for the linker script to decide which output section
1562 the common symbols should be put in. In most cases, the
1563 section of a common symbol will be bfd_com_section_ptr,
1564 the code here will choose a common symbol section named
1565 "COMMON", and the linker script will contain *(COMMON) in
1566 the appropriate place. A few targets use separate common
1567 sections for small symbols, and they require special
1568 handling. */
1569 if (section == bfd_com_section_ptr)
1570 {
1571 h->u.c.section = bfd_make_section_old_way (abfd, "COMMON");
1572 h->u.c.section->flags = SEC_ALLOC;
1573 }
1574 else if (section->owner != abfd)
1575 {
1576 h->u.c.section = bfd_make_section_old_way (abfd, section->name);
1577 h->u.c.section->flags = SEC_ALLOC;
1578 }
1579 else
1580 h->u.c.section = section;
1581 break;
1582
1583 case REF:
1584 /* A reference to a defined symbol. */
1585 if (h->next == NULL && info->hash->undefs_tail != h)
1586 h->next = h;
1587 break;
1588
1589 case BIG:
1590 /* We have found a common definition for a symbol which
1591 already had a common definition. Use the maximum of the
1592 two sizes. */
1593 BFD_ASSERT (h->type == bfd_link_hash_common);
1594 if (! ((*info->callbacks->multiple_common)
1595 (info, name,
1596 h->u.c.section->owner, bfd_link_hash_common, h->u.c.size,
1597 abfd, bfd_link_hash_common, value)))
1598 return false;
1599 if (value > h->u.c.size)
1600 {
1601 unsigned int power;
1602
1603 h->u.c.size = value;
1604
1605 /* Select a default alignment based on the size. This may
1606 be overridden by the caller. */
1607 power = bfd_log2 (value);
1608 if (power > 4)
1609 power = 4;
1610 h->u.c.alignment_power = power;
1611 }
1612 break;
1613
1614 case CREF:
1615 {
1616 bfd *obfd;
1617
1618 /* We have found a common definition for a symbol which
1619 was already defined. FIXME: It would nice if we could
1620 report the BFD which defined an indirect symbol, but we
1621 don't have anywhere to store the information. */
1622 if (h->type == bfd_link_hash_defined
1623 || h->type == bfd_link_hash_defweak)
1624 obfd = h->u.def.section->owner;
1625 else
1626 obfd = NULL;
1627 if (! ((*info->callbacks->multiple_common)
1628 (info, name, obfd, h->type, (bfd_vma) 0,
1629 abfd, bfd_link_hash_common, value)))
1630 return false;
1631 }
1632 break;
1633
1634 case MIND:
1635 /* Multiple indirect symbols. This is OK if they both point
1636 to the same symbol. */
1637 if (strcmp (h->u.i.link->root.string, string) == 0)
1638 break;
1639 /* Fall through. */
1640 case MDEF:
1641 /* Handle a multiple definition. */
1642 {
1643 asection *msec;
1644 bfd_vma mval;
1645
1646 switch (h->type)
1647 {
1648 case bfd_link_hash_defined:
1649 msec = h->u.def.section;
1650 mval = h->u.def.value;
1651 break;
1652 case bfd_link_hash_indirect:
1653 msec = bfd_ind_section_ptr;
1654 mval = 0;
1655 break;
1656 default:
1657 abort ();
1658 }
1659
1660 /* Ignore a redefinition of an absolute symbol to the same
1661 value; it's harmless. */
1662 if (h->type == bfd_link_hash_defined
1663 && bfd_is_abs_section (msec)
1664 && bfd_is_abs_section (section)
1665 && value == mval)
1666 break;
1667
1668 if (! ((*info->callbacks->multiple_definition)
1669 (info, name, msec->owner, msec, mval, abfd, section,
1670 value)))
1671 return false;
1672 }
1673 break;
1674
1675 case CIND:
1676 /* Create an indirect symbol from an existing common symbol. */
1677 BFD_ASSERT (h->type == bfd_link_hash_common);
1678 if (! ((*info->callbacks->multiple_common)
1679 (info, name,
1680 h->u.c.section->owner, bfd_link_hash_common, h->u.c.size,
1681 abfd, bfd_link_hash_indirect, (bfd_vma) 0)))
1682 return false;
1683 /* Fall through. */
1684 case IND:
1685 /* Create an indirect symbol. */
1686 {
1687 struct bfd_link_hash_entry *inh;
1688
1689 /* STRING is the name of the symbol we want to indirect
1690 to. */
1691 inh = bfd_link_hash_lookup (info->hash, string, true, copy,
1692 false);
1693 if (inh == (struct bfd_link_hash_entry *) NULL)
1694 return false;
1695 if (inh->type == bfd_link_hash_new)
1696 {
1697 inh->type = bfd_link_hash_undefined;
1698 inh->u.undef.abfd = abfd;
1699 bfd_link_add_undef (info->hash, inh);
1700 }
1701
1702 /* If the indirect symbol has been referenced, we need to
1703 push the reference down to the symbol we are
1704 referencing. */
1705 if (h->type != bfd_link_hash_new)
1706 {
1707 row = UNDEF_ROW;
1708 cycle = true;
1709 }
1710
1711 h->type = bfd_link_hash_indirect;
1712 h->u.i.link = inh;
1713 }
1714 break;
1715
1716 case SET:
1717 /* Add an entry to a set. */
1718 if (! (*info->callbacks->add_to_set) (info, h, BFD_RELOC_CTOR,
1719 abfd, section, value))
1720 return false;
1721 break;
1722
1723 case WARNC:
1724 /* Issue a warning and cycle. */
1725 if (h->u.i.warning != NULL)
1726 {
1727 if (! (*info->callbacks->warning) (info, h->u.i.warning))
1728 return false;
1729 /* Only issue a warning once. */
1730 h->u.i.warning = NULL;
1731 }
1732 /* Fall through. */
1733 case CYCLE:
1734 /* Try again with the referenced symbol. */
1735 h = h->u.i.link;
1736 cycle = true;
1737 break;
1738
1739 case REFC:
1740 /* A reference to an indirect symbol. */
1741 if (h->next == NULL && info->hash->undefs_tail != h)
1742 h->next = h;
1743 h = h->u.i.link;
1744 cycle = true;
1745 break;
1746
1747 case WARN:
1748 /* Issue a warning. */
1749 if (! (*info->callbacks->warning) (info, string))
1750 return false;
1751 break;
1752
1753 case CWARN:
1754 /* Warn if this symbol has been referenced already,
1755 otherwise add a warning. A symbol has been referenced if
1756 the next field is not NULL, or it is the tail of the
1757 undefined symbol list. The REF case above helps to
1758 ensure this. */
1759 if (h->next != NULL || info->hash->undefs_tail == h)
1760 {
1761 if (! (*info->callbacks->warning) (info, string))
1762 return false;
1763 break;
1764 }
1765 /* Fall through. */
1766 case MWARN:
1767 /* Make a warning symbol. */
1768 {
1769 struct bfd_link_hash_entry *sub;
1770
1771 /* STRING is the warning to give. */
1772 sub = ((struct bfd_link_hash_entry *)
1773 bfd_hash_allocate (&info->hash->table,
1774 sizeof (struct bfd_link_hash_entry)));
1775 if (!sub)
1776 {
1777 bfd_set_error (bfd_error_no_memory);
1778 return false;
1779 }
1780 *sub = *h;
1781 h->type = bfd_link_hash_warning;
1782 h->u.i.link = sub;
1783 if (! copy)
1784 h->u.i.warning = string;
1785 else
1786 {
1787 char *w;
1788
1789 w = bfd_hash_allocate (&info->hash->table,
1790 strlen (string) + 1);
1791 strcpy (w, string);
1792 h->u.i.warning = w;
1793 }
1794 }
1795 break;
1796 }
1797 }
1798 while (cycle);
1799
1800 return true;
1801 }
1802 \f
1803 /* Generic final link routine. */
1804
1805 boolean
1806 _bfd_generic_final_link (abfd, info)
1807 bfd *abfd;
1808 struct bfd_link_info *info;
1809 {
1810 bfd *sub;
1811 asection *o;
1812 struct bfd_link_order *p;
1813 size_t outsymalloc;
1814 struct generic_write_global_symbol_info wginfo;
1815
1816 abfd->outsymbols = (asymbol **) NULL;
1817 abfd->symcount = 0;
1818 outsymalloc = 0;
1819
1820 /* Build the output symbol table. */
1821 for (sub = info->input_bfds; sub != (bfd *) NULL; sub = sub->link_next)
1822 if (! _bfd_generic_link_output_symbols (abfd, sub, info, &outsymalloc))
1823 return false;
1824
1825 /* Accumulate the global symbols. */
1826 wginfo.info = info;
1827 wginfo.output_bfd = abfd;
1828 wginfo.psymalloc = &outsymalloc;
1829 _bfd_generic_link_hash_traverse (_bfd_generic_hash_table (info),
1830 _bfd_generic_link_write_global_symbol,
1831 (PTR) &wginfo);
1832
1833 if (info->relocateable)
1834 {
1835 /* Allocate space for the output relocs for each section. */
1836 for (o = abfd->sections;
1837 o != (asection *) NULL;
1838 o = o->next)
1839 {
1840 o->reloc_count = 0;
1841 for (p = o->link_order_head;
1842 p != (struct bfd_link_order *) NULL;
1843 p = p->next)
1844 {
1845 if (p->type == bfd_section_reloc_link_order
1846 || p->type == bfd_symbol_reloc_link_order)
1847 ++o->reloc_count;
1848 else if (p->type == bfd_indirect_link_order)
1849 {
1850 asection *input_section;
1851 bfd *input_bfd;
1852 long relsize;
1853 arelent **relocs;
1854 asymbol **symbols;
1855 long reloc_count;
1856
1857 input_section = p->u.indirect.section;
1858 input_bfd = input_section->owner;
1859 relsize = bfd_get_reloc_upper_bound (input_bfd,
1860 input_section);
1861 if (relsize < 0)
1862 return false;
1863 relocs = (arelent **) malloc ((size_t) relsize);
1864 if (!relocs && relsize != 0)
1865 {
1866 bfd_set_error (bfd_error_no_memory);
1867 return false;
1868 }
1869 symbols = _bfd_generic_link_get_symbols (input_bfd);
1870 reloc_count = bfd_canonicalize_reloc (input_bfd,
1871 input_section,
1872 relocs,
1873 symbols);
1874 if (reloc_count < 0)
1875 return false;
1876 BFD_ASSERT (reloc_count == input_section->reloc_count);
1877 o->reloc_count += reloc_count;
1878 free (relocs);
1879 }
1880 }
1881 if (o->reloc_count > 0)
1882 {
1883 o->orelocation = ((arelent **)
1884 bfd_alloc (abfd,
1885 (o->reloc_count
1886 * sizeof (arelent *))));
1887 if (!o->orelocation)
1888 {
1889 bfd_set_error (bfd_error_no_memory);
1890 return false;
1891 }
1892 o->flags |= SEC_RELOC;
1893 /* Reset the count so that it can be used as an index
1894 when putting in the output relocs. */
1895 o->reloc_count = 0;
1896 }
1897 }
1898 }
1899
1900 /* Handle all the link order information for the sections. */
1901 for (o = abfd->sections;
1902 o != (asection *) NULL;
1903 o = o->next)
1904 {
1905 for (p = o->link_order_head;
1906 p != (struct bfd_link_order *) NULL;
1907 p = p->next)
1908 {
1909 switch (p->type)
1910 {
1911 case bfd_section_reloc_link_order:
1912 case bfd_symbol_reloc_link_order:
1913 if (! _bfd_generic_reloc_link_order (abfd, info, o, p))
1914 return false;
1915 break;
1916 case bfd_indirect_link_order:
1917 if (! default_indirect_link_order (abfd, info, o, p, true))
1918 return false;
1919 break;
1920 default:
1921 if (! _bfd_default_link_order (abfd, info, o, p))
1922 return false;
1923 break;
1924 }
1925 }
1926 }
1927
1928 return true;
1929 }
1930
1931 /* Add an output symbol to the output BFD. */
1932
1933 static boolean
1934 generic_add_output_symbol (output_bfd, psymalloc, sym)
1935 bfd *output_bfd;
1936 size_t *psymalloc;
1937 asymbol *sym;
1938 {
1939 if (output_bfd->symcount >= *psymalloc)
1940 {
1941 asymbol **newsyms;
1942
1943 if (*psymalloc == 0)
1944 *psymalloc = 124;
1945 else
1946 *psymalloc *= 2;
1947 if (output_bfd->outsymbols == (asymbol **) NULL)
1948 newsyms = (asymbol **) malloc (*psymalloc * sizeof (asymbol *));
1949 else
1950 newsyms = (asymbol **) realloc (output_bfd->outsymbols,
1951 *psymalloc * sizeof (asymbol *));
1952 if (newsyms == (asymbol **) NULL)
1953 {
1954 bfd_set_error (bfd_error_no_memory);
1955 return false;
1956 }
1957 output_bfd->outsymbols = newsyms;
1958 }
1959
1960 output_bfd->outsymbols[output_bfd->symcount] = sym;
1961 ++output_bfd->symcount;
1962
1963 return true;
1964 }
1965
1966 /* Handle the symbols for an input BFD. */
1967
1968 boolean
1969 _bfd_generic_link_output_symbols (output_bfd, input_bfd, info, psymalloc)
1970 bfd *output_bfd;
1971 bfd *input_bfd;
1972 struct bfd_link_info *info;
1973 size_t *psymalloc;
1974 {
1975 asymbol **sym_ptr;
1976 asymbol **sym_end;
1977
1978 if (! generic_link_read_symbols (input_bfd))
1979 return false;
1980
1981 /* Create a filename symbol if we are supposed to. */
1982 if (info->create_object_symbols_section != (asection *) NULL)
1983 {
1984 asection *sec;
1985
1986 for (sec = input_bfd->sections;
1987 sec != (asection *) NULL;
1988 sec = sec->next)
1989 {
1990 if (sec->output_section == info->create_object_symbols_section)
1991 {
1992 asymbol *newsym;
1993
1994 newsym = bfd_make_empty_symbol (input_bfd);
1995 if (!newsym)
1996 return false;
1997 newsym->name = input_bfd->filename;
1998 newsym->value = 0;
1999 newsym->flags = BSF_LOCAL | BSF_FILE;
2000 newsym->section = sec;
2001
2002 if (! generic_add_output_symbol (output_bfd, psymalloc,
2003 newsym))
2004 return false;
2005
2006 break;
2007 }
2008 }
2009 }
2010
2011 /* Adjust the values of the globally visible symbols, and write out
2012 local symbols. */
2013 sym_ptr = _bfd_generic_link_get_symbols (input_bfd);
2014 sym_end = sym_ptr + _bfd_generic_link_get_symcount (input_bfd);
2015 for (; sym_ptr < sym_end; sym_ptr++)
2016 {
2017 asymbol *sym;
2018 struct generic_link_hash_entry *h;
2019 boolean output;
2020
2021 h = (struct generic_link_hash_entry *) NULL;
2022 sym = *sym_ptr;
2023 if ((sym->flags & (BSF_INDIRECT
2024 | BSF_WARNING
2025 | BSF_GLOBAL
2026 | BSF_CONSTRUCTOR
2027 | BSF_WEAK)) != 0
2028 || bfd_is_und_section (bfd_get_section (sym))
2029 || bfd_is_com_section (bfd_get_section (sym))
2030 || bfd_is_ind_section (bfd_get_section (sym)))
2031 {
2032 h = _bfd_generic_link_hash_lookup (_bfd_generic_hash_table (info),
2033 bfd_asymbol_name (sym),
2034 false, false, true);
2035 if (h != (struct generic_link_hash_entry *) NULL)
2036 {
2037 /* Force all references to this symbol to point to
2038 the same area in memory. It is possible that
2039 this routine will be called with a hash table
2040 other than a generic hash table, so we double
2041 check that. */
2042 if (info->hash->creator == input_bfd->xvec)
2043 {
2044 if (h->sym != (asymbol *) NULL)
2045 *sym_ptr = sym = h->sym;
2046 }
2047
2048 switch (h->root.type)
2049 {
2050 default:
2051 case bfd_link_hash_new:
2052 abort ();
2053 case bfd_link_hash_undefined:
2054 break;
2055 case bfd_link_hash_undefweak:
2056 sym->flags |= BSF_WEAK;
2057 break;
2058 case bfd_link_hash_defined:
2059 sym->flags |= BSF_GLOBAL;
2060 sym->value = h->root.u.def.value;
2061 sym->section = h->root.u.def.section;
2062 break;
2063 case bfd_link_hash_defweak:
2064 sym->flags |= BSF_WEAK;
2065 sym->value = h->root.u.def.value;
2066 sym->section = h->root.u.def.section;
2067 break;
2068 case bfd_link_hash_common:
2069 sym->value = h->root.u.c.size;
2070 sym->flags |= BSF_GLOBAL;
2071 if (! bfd_is_com_section (sym->section))
2072 {
2073 BFD_ASSERT (bfd_is_und_section (sym->section));
2074 sym->section = bfd_com_section_ptr;
2075 }
2076 /* We do not set the section of the symbol to
2077 h->root.u.c.section. That value was saved so
2078 that we would know where to allocate the symbol
2079 if it was defined. In this case the type is
2080 still bfd_link_hash_common, so we did not define
2081 it, so we do not want to use that section. */
2082 break;
2083 }
2084 }
2085 }
2086
2087 /* This switch is straight from the old code in
2088 write_file_locals in ldsym.c. */
2089 if (info->strip == strip_some
2090 && (bfd_hash_lookup (info->keep_hash, bfd_asymbol_name (sym),
2091 false, false)
2092 == (struct bfd_hash_entry *) NULL))
2093 output = false;
2094 else if ((sym->flags & (BSF_GLOBAL | BSF_WEAK)) != 0)
2095 {
2096 /* If this symbol is marked as occurring now, rather
2097 than at the end, output it now. This is used for
2098 COFF C_EXT FCN symbols. FIXME: There must be a
2099 better way. */
2100 if (bfd_asymbol_bfd (sym) == input_bfd
2101 && (sym->flags & BSF_NOT_AT_END) != 0)
2102 output = true;
2103 else
2104 output = false;
2105 }
2106 else if (bfd_is_ind_section (sym->section))
2107 output = false;
2108 else if ((sym->flags & BSF_DEBUGGING) != 0)
2109 {
2110 if (info->strip == strip_none)
2111 output = true;
2112 else
2113 output = false;
2114 }
2115 else if (bfd_is_und_section (sym->section)
2116 || bfd_is_com_section (sym->section))
2117 output = false;
2118 else if ((sym->flags & BSF_LOCAL) != 0)
2119 {
2120 if ((sym->flags & BSF_WARNING) != 0)
2121 output = false;
2122 else
2123 {
2124 switch (info->discard)
2125 {
2126 default:
2127 case discard_all:
2128 output = false;
2129 break;
2130 case discard_l:
2131 if (bfd_asymbol_name (sym)[0] == info->lprefix[0]
2132 && (info->lprefix_len == 1
2133 || strncmp (bfd_asymbol_name (sym), info->lprefix,
2134 info->lprefix_len) == 0))
2135 output = false;
2136 else
2137 output = true;
2138 break;
2139 case discard_none:
2140 output = true;
2141 break;
2142 }
2143 }
2144 }
2145 else if ((sym->flags & BSF_CONSTRUCTOR))
2146 {
2147 if (info->strip != strip_all)
2148 output = true;
2149 else
2150 output = false;
2151 }
2152 else
2153 abort ();
2154
2155 if (output)
2156 {
2157 if (! generic_add_output_symbol (output_bfd, psymalloc, sym))
2158 return false;
2159 if (h != (struct generic_link_hash_entry *) NULL)
2160 h->written = true;
2161 }
2162 }
2163
2164 return true;
2165 }
2166
2167 /* Set the section and value of a generic BFD symbol based on a linker
2168 hash table entry. */
2169
2170 static void
2171 set_symbol_from_hash (sym, h)
2172 asymbol *sym;
2173 struct bfd_link_hash_entry *h;
2174 {
2175 switch (h->type)
2176 {
2177 default:
2178 case bfd_link_hash_new:
2179 abort ();
2180 case bfd_link_hash_undefined:
2181 sym->section = bfd_und_section_ptr;
2182 sym->value = 0;
2183 break;
2184 case bfd_link_hash_undefweak:
2185 sym->section = bfd_und_section_ptr;
2186 sym->value = 0;
2187 sym->flags |= BSF_WEAK;
2188 break;
2189 case bfd_link_hash_defined:
2190 sym->section = h->u.def.section;
2191 sym->value = h->u.def.value;
2192 break;
2193 case bfd_link_hash_defweak:
2194 sym->flags |= BSF_WEAK;
2195 sym->section = h->u.def.section;
2196 sym->value = h->u.def.value;
2197 break;
2198 case bfd_link_hash_common:
2199 sym->value = h->u.c.size;
2200 if (sym->section == NULL)
2201 sym->section = bfd_com_section_ptr;
2202 else if (! bfd_is_com_section (sym->section))
2203 {
2204 BFD_ASSERT (bfd_is_und_section (sym->section));
2205 sym->section = bfd_com_section_ptr;
2206 }
2207 /* Do not set the section; see _bfd_generic_link_output_symbols. */
2208 break;
2209 case bfd_link_hash_indirect:
2210 case bfd_link_hash_warning:
2211 /* FIXME: What should we do here? */
2212 break;
2213 }
2214 }
2215
2216 /* Write out a global symbol, if it hasn't already been written out.
2217 This is called for each symbol in the hash table. */
2218
2219 boolean
2220 _bfd_generic_link_write_global_symbol (h, data)
2221 struct generic_link_hash_entry *h;
2222 PTR data;
2223 {
2224 struct generic_write_global_symbol_info *wginfo =
2225 (struct generic_write_global_symbol_info *) data;
2226 asymbol *sym;
2227
2228 if (h->written)
2229 return true;
2230
2231 h->written = true;
2232
2233 if (wginfo->info->strip == strip_all
2234 || (wginfo->info->strip == strip_some
2235 && bfd_hash_lookup (wginfo->info->keep_hash, h->root.root.string,
2236 false, false) == NULL))
2237 return true;
2238
2239 if (h->sym != (asymbol *) NULL)
2240 {
2241 sym = h->sym;
2242 BFD_ASSERT (strcmp (bfd_asymbol_name (sym), h->root.root.string) == 0);
2243 }
2244 else
2245 {
2246 sym = bfd_make_empty_symbol (wginfo->output_bfd);
2247 if (!sym)
2248 return false;
2249 sym->name = h->root.root.string;
2250 sym->flags = 0;
2251 }
2252
2253 set_symbol_from_hash (sym, &h->root);
2254
2255 sym->flags |= BSF_GLOBAL;
2256
2257 if (! generic_add_output_symbol (wginfo->output_bfd, wginfo->psymalloc,
2258 sym))
2259 {
2260 /* FIXME: No way to return failure. */
2261 abort ();
2262 }
2263
2264 return true;
2265 }
2266
2267 /* Create a relocation. */
2268
2269 boolean
2270 _bfd_generic_reloc_link_order (abfd, info, sec, link_order)
2271 bfd *abfd;
2272 struct bfd_link_info *info;
2273 asection *sec;
2274 struct bfd_link_order *link_order;
2275 {
2276 arelent *r;
2277
2278 if (! info->relocateable)
2279 abort ();
2280 if (sec->orelocation == (arelent **) NULL)
2281 abort ();
2282
2283 r = (arelent *) bfd_alloc (abfd, sizeof (arelent));
2284 if (r == (arelent *) NULL)
2285 {
2286 bfd_set_error (bfd_error_no_memory);
2287 return false;
2288 }
2289
2290 r->address = link_order->offset;
2291 r->howto = bfd_reloc_type_lookup (abfd, link_order->u.reloc.p->reloc);
2292 if (r->howto == 0)
2293 {
2294 bfd_set_error (bfd_error_bad_value);
2295 return false;
2296 }
2297
2298 /* Get the symbol to use for the relocation. */
2299 if (link_order->type == bfd_section_reloc_link_order)
2300 r->sym_ptr_ptr = link_order->u.reloc.p->u.section->symbol_ptr_ptr;
2301 else
2302 {
2303 struct generic_link_hash_entry *h;
2304
2305 h = _bfd_generic_link_hash_lookup (_bfd_generic_hash_table (info),
2306 link_order->u.reloc.p->u.name,
2307 false, false, true);
2308 if (h == (struct generic_link_hash_entry *) NULL
2309 || ! h->written)
2310 {
2311 if (! ((*info->callbacks->unattached_reloc)
2312 (info, link_order->u.reloc.p->u.name,
2313 (bfd *) NULL, (asection *) NULL, (bfd_vma) 0)))
2314 return false;
2315 bfd_set_error (bfd_error_bad_value);
2316 return false;
2317 }
2318 r->sym_ptr_ptr = &h->sym;
2319 }
2320
2321 /* If this is an inplace reloc, write the addend to the object file.
2322 Otherwise, store it in the reloc addend. */
2323 if (! r->howto->partial_inplace)
2324 r->addend = link_order->u.reloc.p->addend;
2325 else
2326 {
2327 bfd_size_type size;
2328 bfd_reloc_status_type rstat;
2329 bfd_byte *buf;
2330 boolean ok;
2331
2332 size = bfd_get_reloc_size (r->howto);
2333 buf = (bfd_byte *) bfd_zmalloc (size);
2334 if (buf == (bfd_byte *) NULL)
2335 {
2336 bfd_set_error (bfd_error_no_memory);
2337 return false;
2338 }
2339 rstat = _bfd_relocate_contents (r->howto, abfd,
2340 link_order->u.reloc.p->addend, buf);
2341 switch (rstat)
2342 {
2343 case bfd_reloc_ok:
2344 break;
2345 default:
2346 case bfd_reloc_outofrange:
2347 abort ();
2348 case bfd_reloc_overflow:
2349 if (! ((*info->callbacks->reloc_overflow)
2350 (info,
2351 (link_order->type == bfd_section_reloc_link_order
2352 ? bfd_section_name (abfd, link_order->u.reloc.p->u.section)
2353 : link_order->u.reloc.p->u.name),
2354 r->howto->name, link_order->u.reloc.p->addend,
2355 (bfd *) NULL, (asection *) NULL, (bfd_vma) 0)))
2356 {
2357 free (buf);
2358 return false;
2359 }
2360 break;
2361 }
2362 ok = bfd_set_section_contents (abfd, sec, (PTR) buf,
2363 (file_ptr) link_order->offset, size);
2364 free (buf);
2365 if (! ok)
2366 return false;
2367
2368 r->addend = 0;
2369 }
2370
2371 sec->orelocation[sec->reloc_count] = r;
2372 ++sec->reloc_count;
2373
2374 return true;
2375 }
2376 \f
2377 /* Allocate a new link_order for a section. */
2378
2379 struct bfd_link_order *
2380 bfd_new_link_order (abfd, section)
2381 bfd *abfd;
2382 asection *section;
2383 {
2384 struct bfd_link_order *new;
2385
2386 new = ((struct bfd_link_order *)
2387 bfd_alloc_by_size_t (abfd, sizeof (struct bfd_link_order)));
2388 if (!new)
2389 {
2390 bfd_set_error (bfd_error_no_memory);
2391 return NULL;
2392 }
2393
2394 new->type = bfd_undefined_link_order;
2395 new->offset = 0;
2396 new->size = 0;
2397 new->next = (struct bfd_link_order *) NULL;
2398
2399 if (section->link_order_tail != (struct bfd_link_order *) NULL)
2400 section->link_order_tail->next = new;
2401 else
2402 section->link_order_head = new;
2403 section->link_order_tail = new;
2404
2405 return new;
2406 }
2407
2408 /* Default link order processing routine. Note that we can not handle
2409 the reloc_link_order types here, since they depend upon the details
2410 of how the particular backends generates relocs. */
2411
2412 boolean
2413 _bfd_default_link_order (abfd, info, sec, link_order)
2414 bfd *abfd;
2415 struct bfd_link_info *info;
2416 asection *sec;
2417 struct bfd_link_order *link_order;
2418 {
2419 switch (link_order->type)
2420 {
2421 case bfd_undefined_link_order:
2422 case bfd_section_reloc_link_order:
2423 case bfd_symbol_reloc_link_order:
2424 default:
2425 abort ();
2426 case bfd_indirect_link_order:
2427 return default_indirect_link_order (abfd, info, sec, link_order,
2428 false);
2429 case bfd_fill_link_order:
2430 return default_fill_link_order (abfd, info, sec, link_order);
2431 case bfd_data_link_order:
2432 return bfd_set_section_contents (abfd, sec,
2433 (PTR) link_order->u.data.contents,
2434 (file_ptr) link_order->offset,
2435 link_order->size);
2436 }
2437 }
2438
2439 /* Default routine to handle a bfd_fill_link_order. */
2440
2441 /*ARGSUSED*/
2442 static boolean
2443 default_fill_link_order (abfd, info, sec, link_order)
2444 bfd *abfd;
2445 struct bfd_link_info *info;
2446 asection *sec;
2447 struct bfd_link_order *link_order;
2448 {
2449 size_t size;
2450 char *space;
2451 size_t i;
2452 int fill;
2453 boolean result;
2454
2455 BFD_ASSERT ((sec->flags & SEC_HAS_CONTENTS) != 0);
2456
2457 size = (size_t) link_order->size;
2458 space = (char *) malloc (size);
2459 if (space == NULL && size != 0)
2460 {
2461 bfd_set_error (bfd_error_no_memory);
2462 return false;
2463 }
2464
2465 fill = link_order->u.fill.value;
2466 for (i = 0; i < size; i += 2)
2467 space[i] = fill >> 8;
2468 for (i = 1; i < size; i += 2)
2469 space[i] = fill;
2470 result = bfd_set_section_contents (abfd, sec, space,
2471 (file_ptr) link_order->offset,
2472 link_order->size);
2473 free (space);
2474 return result;
2475 }
2476
2477 /* Default routine to handle a bfd_indirect_link_order. */
2478
2479 static boolean
2480 default_indirect_link_order (output_bfd, info, output_section, link_order,
2481 generic_linker)
2482 bfd *output_bfd;
2483 struct bfd_link_info *info;
2484 asection *output_section;
2485 struct bfd_link_order *link_order;
2486 boolean generic_linker;
2487 {
2488 asection *input_section;
2489 bfd *input_bfd;
2490 bfd_byte *contents = NULL;
2491 bfd_byte *new_contents;
2492
2493 BFD_ASSERT ((output_section->flags & SEC_HAS_CONTENTS) != 0);
2494
2495 if (link_order->size == 0)
2496 return true;
2497
2498 input_section = link_order->u.indirect.section;
2499 input_bfd = input_section->owner;
2500
2501 BFD_ASSERT (input_section->output_section == output_section);
2502 BFD_ASSERT (input_section->output_offset == link_order->offset);
2503 BFD_ASSERT (input_section->_cooked_size == link_order->size);
2504
2505 if (info->relocateable
2506 && input_section->reloc_count > 0
2507 && output_section->orelocation == (arelent **) NULL)
2508 {
2509 /* Space has not been allocated for the output relocations.
2510 This can happen when we are called by a specific backend
2511 because somebody is attempting to link together different
2512 types of object files. Handling this case correctly is
2513 difficult, and sometimes impossible. */
2514 abort ();
2515 }
2516
2517 if (! generic_linker)
2518 {
2519 asymbol **sympp;
2520 asymbol **symppend;
2521
2522 /* Get the canonical symbols. The generic linker will always
2523 have retrieved them by this point, but we are being called by
2524 a specific linker, presumably because we are linking
2525 different types of object files together. */
2526 if (! generic_link_read_symbols (input_bfd))
2527 return false;
2528
2529 /* Since we have been called by a specific linker, rather than
2530 the generic linker, the values of the symbols will not be
2531 right. They will be the values as seen in the input file,
2532 not the values of the final link. We need to fix them up
2533 before we can relocate the section. */
2534 sympp = _bfd_generic_link_get_symbols (input_bfd);
2535 symppend = sympp + _bfd_generic_link_get_symcount (input_bfd);
2536 for (; sympp < symppend; sympp++)
2537 {
2538 asymbol *sym;
2539 struct bfd_link_hash_entry *h;
2540
2541 sym = *sympp;
2542
2543 if ((sym->flags & (BSF_INDIRECT
2544 | BSF_WARNING
2545 | BSF_GLOBAL
2546 | BSF_CONSTRUCTOR
2547 | BSF_WEAK)) != 0
2548 || bfd_is_und_section (bfd_get_section (sym))
2549 || bfd_is_com_section (bfd_get_section (sym))
2550 || bfd_is_ind_section (bfd_get_section (sym)))
2551 {
2552 /* sym->udata may have been set by
2553 generic_link_add_symbol_list. */
2554 if (sym->udata.p != NULL)
2555 h = (struct bfd_link_hash_entry *) sym->udata.p;
2556 else
2557 h = bfd_link_hash_lookup (info->hash,
2558 bfd_asymbol_name (sym),
2559 false, false, true);
2560 if (h != NULL)
2561 set_symbol_from_hash (sym, h);
2562 }
2563 }
2564 }
2565
2566 /* Get and relocate the section contents. */
2567 contents = (bfd_byte *) malloc (bfd_section_size (input_bfd, input_section));
2568 if (contents == NULL && bfd_section_size (input_bfd, input_section) != 0)
2569 {
2570 bfd_set_error (bfd_error_no_memory);
2571 goto error_return;
2572 }
2573 new_contents = (bfd_get_relocated_section_contents
2574 (output_bfd, info, link_order, contents, info->relocateable,
2575 _bfd_generic_link_get_symbols (input_bfd)));
2576 if (!new_contents)
2577 goto error_return;
2578
2579 /* Output the section contents. */
2580 if (! bfd_set_section_contents (output_bfd, output_section,
2581 (PTR) new_contents,
2582 link_order->offset, link_order->size))
2583 goto error_return;
2584
2585 if (contents != NULL)
2586 free (contents);
2587 return true;
2588
2589 error_return:
2590 if (contents != NULL)
2591 free (contents);
2592 return false;
2593 }
2594
2595 /* A little routine to count the number of relocs in a link_order
2596 list. */
2597
2598 unsigned int
2599 _bfd_count_link_order_relocs (link_order)
2600 struct bfd_link_order *link_order;
2601 {
2602 register unsigned int c;
2603 register struct bfd_link_order *l;
2604
2605 c = 0;
2606 for (l = link_order; l != (struct bfd_link_order *) NULL; l = l->next)
2607 {
2608 if (l->type == bfd_section_reloc_link_order
2609 || l->type == bfd_symbol_reloc_link_order)
2610 ++c;
2611 }
2612
2613 return c;
2614 }
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