* output-file.c (output_file_create): Don't try to open using
[binutils.git] / bfd / linker.c
blob1144e92dbfc2e54dc5a6e0c472e657f4cc47439b
1 /* linker.c -- BFD linker routines
2 Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001
3 Free Software Foundation, Inc.
4 Written by Steve Chamberlain and Ian Lance Taylor, Cygnus Support
6 This file is part of BFD, the Binary File Descriptor library.
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
22 #include "bfd.h"
23 #include "sysdep.h"
24 #include "libbfd.h"
25 #include "bfdlink.h"
26 #include "genlink.h"
29 SECTION
30 Linker Functions
32 @cindex Linker
33 The linker uses three special entry points in the BFD target
34 vector. It is not necessary to write special routines for
35 these entry points when creating a new BFD back end, since
36 generic versions are provided. However, writing them can
37 speed up linking and make it use significantly less runtime
38 memory.
40 The first routine creates a hash table used by the other
41 routines. The second routine adds the symbols from an object
42 file to the hash table. The third routine takes all the
43 object files and links them together to create the output
44 file. These routines are designed so that the linker proper
45 does not need to know anything about the symbols in the object
46 files that it is linking. The linker merely arranges the
47 sections as directed by the linker script and lets BFD handle
48 the details of symbols and relocs.
50 The second routine and third routines are passed a pointer to
51 a <<struct bfd_link_info>> structure (defined in
52 <<bfdlink.h>>) which holds information relevant to the link,
53 including the linker hash table (which was created by the
54 first routine) and a set of callback functions to the linker
55 proper.
57 The generic linker routines are in <<linker.c>>, and use the
58 header file <<genlink.h>>. As of this writing, the only back
59 ends which have implemented versions of these routines are
60 a.out (in <<aoutx.h>>) and ECOFF (in <<ecoff.c>>). The a.out
61 routines are used as examples throughout this section.
63 @menu
64 @* Creating a Linker Hash Table::
65 @* Adding Symbols to the Hash Table::
66 @* Performing the Final Link::
67 @end menu
69 INODE
70 Creating a Linker Hash Table, Adding Symbols to the Hash Table, Linker Functions, Linker Functions
71 SUBSECTION
72 Creating a linker hash table
74 @cindex _bfd_link_hash_table_create in target vector
75 @cindex target vector (_bfd_link_hash_table_create)
76 The linker routines must create a hash table, which must be
77 derived from <<struct bfd_link_hash_table>> described in
78 <<bfdlink.c>>. @xref{Hash Tables}, for information on how to
79 create a derived hash table. This entry point is called using
80 the target vector of the linker output file.
82 The <<_bfd_link_hash_table_create>> entry point must allocate
83 and initialize an instance of the desired hash table. If the
84 back end does not require any additional information to be
85 stored with the entries in the hash table, the entry point may
86 simply create a <<struct bfd_link_hash_table>>. Most likely,
87 however, some additional information will be needed.
89 For example, with each entry in the hash table the a.out
90 linker keeps the index the symbol has in the final output file
91 (this index number is used so that when doing a relocateable
92 link the symbol index used in the output file can be quickly
93 filled in when copying over a reloc). The a.out linker code
94 defines the required structures and functions for a hash table
95 derived from <<struct bfd_link_hash_table>>. The a.out linker
96 hash table is created by the function
97 <<NAME(aout,link_hash_table_create)>>; it simply allocates
98 space for the hash table, initializes it, and returns a
99 pointer to it.
101 When writing the linker routines for a new back end, you will
102 generally not know exactly which fields will be required until
103 you have finished. You should simply create a new hash table
104 which defines no additional fields, and then simply add fields
105 as they become necessary.
107 INODE
108 Adding Symbols to the Hash Table, Performing the Final Link, Creating a Linker Hash Table, Linker Functions
109 SUBSECTION
110 Adding symbols to the hash table
112 @cindex _bfd_link_add_symbols in target vector
113 @cindex target vector (_bfd_link_add_symbols)
114 The linker proper will call the <<_bfd_link_add_symbols>>
115 entry point for each object file or archive which is to be
116 linked (typically these are the files named on the command
117 line, but some may also come from the linker script). The
118 entry point is responsible for examining the file. For an
119 object file, BFD must add any relevant symbol information to
120 the hash table. For an archive, BFD must determine which
121 elements of the archive should be used and adding them to the
122 link.
124 The a.out version of this entry point is
125 <<NAME(aout,link_add_symbols)>>.
127 @menu
128 @* Differing file formats::
129 @* Adding symbols from an object file::
130 @* Adding symbols from an archive::
131 @end menu
133 INODE
134 Differing file formats, Adding symbols from an object file, Adding Symbols to the Hash Table, Adding Symbols to the Hash Table
135 SUBSUBSECTION
136 Differing file formats
138 Normally all the files involved in a link will be of the same
139 format, but it is also possible to link together different
140 format object files, and the back end must support that. The
141 <<_bfd_link_add_symbols>> entry point is called via the target
142 vector of the file to be added. This has an important
143 consequence: the function may not assume that the hash table
144 is the type created by the corresponding
145 <<_bfd_link_hash_table_create>> vector. All the
146 <<_bfd_link_add_symbols>> function can assume about the hash
147 table is that it is derived from <<struct
148 bfd_link_hash_table>>.
150 Sometimes the <<_bfd_link_add_symbols>> function must store
151 some information in the hash table entry to be used by the
152 <<_bfd_final_link>> function. In such a case the <<creator>>
153 field of the hash table must be checked to make sure that the
154 hash table was created by an object file of the same format.
156 The <<_bfd_final_link>> routine must be prepared to handle a
157 hash entry without any extra information added by the
158 <<_bfd_link_add_symbols>> function. A hash entry without
159 extra information will also occur when the linker script
160 directs the linker to create a symbol. Note that, regardless
161 of how a hash table entry is added, all the fields will be
162 initialized to some sort of null value by the hash table entry
163 initialization function.
165 See <<ecoff_link_add_externals>> for an example of how to
166 check the <<creator>> field before saving information (in this
167 case, the ECOFF external symbol debugging information) in a
168 hash table entry.
170 INODE
171 Adding symbols from an object file, Adding symbols from an archive, Differing file formats, Adding Symbols to the Hash Table
172 SUBSUBSECTION
173 Adding symbols from an object file
175 When the <<_bfd_link_add_symbols>> routine is passed an object
176 file, it must add all externally visible symbols in that
177 object file to the hash table. The actual work of adding the
178 symbol to the hash table is normally handled by the function
179 <<_bfd_generic_link_add_one_symbol>>. The
180 <<_bfd_link_add_symbols>> routine is responsible for reading
181 all the symbols from the object file and passing the correct
182 information to <<_bfd_generic_link_add_one_symbol>>.
184 The <<_bfd_link_add_symbols>> routine should not use
185 <<bfd_canonicalize_symtab>> to read the symbols. The point of
186 providing this routine is to avoid the overhead of converting
187 the symbols into generic <<asymbol>> structures.
189 @findex _bfd_generic_link_add_one_symbol
190 <<_bfd_generic_link_add_one_symbol>> handles the details of
191 combining common symbols, warning about multiple definitions,
192 and so forth. It takes arguments which describe the symbol to
193 add, notably symbol flags, a section, and an offset. The
194 symbol flags include such things as <<BSF_WEAK>> or
195 <<BSF_INDIRECT>>. The section is a section in the object
196 file, or something like <<bfd_und_section_ptr>> for an undefined
197 symbol or <<bfd_com_section_ptr>> for a common symbol.
199 If the <<_bfd_final_link>> routine is also going to need to
200 read the symbol information, the <<_bfd_link_add_symbols>>
201 routine should save it somewhere attached to the object file
202 BFD. However, the information should only be saved if the
203 <<keep_memory>> field of the <<info>> argument is true, so
204 that the <<-no-keep-memory>> linker switch is effective.
206 The a.out function which adds symbols from an object file is
207 <<aout_link_add_object_symbols>>, and most of the interesting
208 work is in <<aout_link_add_symbols>>. The latter saves
209 pointers to the hash tables entries created by
210 <<_bfd_generic_link_add_one_symbol>> indexed by symbol number,
211 so that the <<_bfd_final_link>> routine does not have to call
212 the hash table lookup routine to locate the entry.
214 INODE
215 Adding symbols from an archive, , Adding symbols from an object file, Adding Symbols to the Hash Table
216 SUBSUBSECTION
217 Adding symbols from an archive
219 When the <<_bfd_link_add_symbols>> routine is passed an
220 archive, it must look through the symbols defined by the
221 archive and decide which elements of the archive should be
222 included in the link. For each such element it must call the
223 <<add_archive_element>> linker callback, and it must add the
224 symbols from the object file to the linker hash table.
226 @findex _bfd_generic_link_add_archive_symbols
227 In most cases the work of looking through the symbols in the
228 archive should be done by the
229 <<_bfd_generic_link_add_archive_symbols>> function. This
230 function builds a hash table from the archive symbol table and
231 looks through the list of undefined symbols to see which
232 elements should be included.
233 <<_bfd_generic_link_add_archive_symbols>> is passed a function
234 to call to make the final decision about adding an archive
235 element to the link and to do the actual work of adding the
236 symbols to the linker hash table.
238 The function passed to
239 <<_bfd_generic_link_add_archive_symbols>> must read the
240 symbols of the archive element and decide whether the archive
241 element should be included in the link. If the element is to
242 be included, the <<add_archive_element>> linker callback
243 routine must be called with the element as an argument, and
244 the elements symbols must be added to the linker hash table
245 just as though the element had itself been passed to the
246 <<_bfd_link_add_symbols>> function.
248 When the a.out <<_bfd_link_add_symbols>> function receives an
249 archive, it calls <<_bfd_generic_link_add_archive_symbols>>
250 passing <<aout_link_check_archive_element>> as the function
251 argument. <<aout_link_check_archive_element>> calls
252 <<aout_link_check_ar_symbols>>. If the latter decides to add
253 the element (an element is only added if it provides a real,
254 non-common, definition for a previously undefined or common
255 symbol) it calls the <<add_archive_element>> callback and then
256 <<aout_link_check_archive_element>> calls
257 <<aout_link_add_symbols>> to actually add the symbols to the
258 linker hash table.
260 The ECOFF back end is unusual in that it does not normally
261 call <<_bfd_generic_link_add_archive_symbols>>, because ECOFF
262 archives already contain a hash table of symbols. The ECOFF
263 back end searches the archive itself to avoid the overhead of
264 creating a new hash table.
266 INODE
267 Performing the Final Link, , Adding Symbols to the Hash Table, Linker Functions
268 SUBSECTION
269 Performing the final link
271 @cindex _bfd_link_final_link in target vector
272 @cindex target vector (_bfd_final_link)
273 When all the input files have been processed, the linker calls
274 the <<_bfd_final_link>> entry point of the output BFD. This
275 routine is responsible for producing the final output file,
276 which has several aspects. It must relocate the contents of
277 the input sections and copy the data into the output sections.
278 It must build an output symbol table including any local
279 symbols from the input files and the global symbols from the
280 hash table. When producing relocateable output, it must
281 modify the input relocs and write them into the output file.
282 There may also be object format dependent work to be done.
284 The linker will also call the <<write_object_contents>> entry
285 point when the BFD is closed. The two entry points must work
286 together in order to produce the correct output file.
288 The details of how this works are inevitably dependent upon
289 the specific object file format. The a.out
290 <<_bfd_final_link>> routine is <<NAME(aout,final_link)>>.
292 @menu
293 @* Information provided by the linker::
294 @* Relocating the section contents::
295 @* Writing the symbol table::
296 @end menu
298 INODE
299 Information provided by the linker, Relocating the section contents, Performing the Final Link, Performing the Final Link
300 SUBSUBSECTION
301 Information provided by the linker
303 Before the linker calls the <<_bfd_final_link>> entry point,
304 it sets up some data structures for the function to use.
306 The <<input_bfds>> field of the <<bfd_link_info>> structure
307 will point to a list of all the input files included in the
308 link. These files are linked through the <<link_next>> field
309 of the <<bfd>> structure.
311 Each section in the output file will have a list of
312 <<link_order>> structures attached to the <<link_order_head>>
313 field (the <<link_order>> structure is defined in
314 <<bfdlink.h>>). These structures describe how to create the
315 contents of the output section in terms of the contents of
316 various input sections, fill constants, and, eventually, other
317 types of information. They also describe relocs that must be
318 created by the BFD backend, but do not correspond to any input
319 file; this is used to support -Ur, which builds constructors
320 while generating a relocateable object file.
322 INODE
323 Relocating the section contents, Writing the symbol table, Information provided by the linker, Performing the Final Link
324 SUBSUBSECTION
325 Relocating the section contents
327 The <<_bfd_final_link>> function should look through the
328 <<link_order>> structures attached to each section of the
329 output file. Each <<link_order>> structure should either be
330 handled specially, or it should be passed to the function
331 <<_bfd_default_link_order>> which will do the right thing
332 (<<_bfd_default_link_order>> is defined in <<linker.c>>).
334 For efficiency, a <<link_order>> of type
335 <<bfd_indirect_link_order>> whose associated section belongs
336 to a BFD of the same format as the output BFD must be handled
337 specially. This type of <<link_order>> describes part of an
338 output section in terms of a section belonging to one of the
339 input files. The <<_bfd_final_link>> function should read the
340 contents of the section and any associated relocs, apply the
341 relocs to the section contents, and write out the modified
342 section contents. If performing a relocateable link, the
343 relocs themselves must also be modified and written out.
345 @findex _bfd_relocate_contents
346 @findex _bfd_final_link_relocate
347 The functions <<_bfd_relocate_contents>> and
348 <<_bfd_final_link_relocate>> provide some general support for
349 performing the actual relocations, notably overflow checking.
350 Their arguments include information about the symbol the
351 relocation is against and a <<reloc_howto_type>> argument
352 which describes the relocation to perform. These functions
353 are defined in <<reloc.c>>.
355 The a.out function which handles reading, relocating, and
356 writing section contents is <<aout_link_input_section>>. The
357 actual relocation is done in <<aout_link_input_section_std>>
358 and <<aout_link_input_section_ext>>.
360 INODE
361 Writing the symbol table, , Relocating the section contents, Performing the Final Link
362 SUBSUBSECTION
363 Writing the symbol table
365 The <<_bfd_final_link>> function must gather all the symbols
366 in the input files and write them out. It must also write out
367 all the symbols in the global hash table. This must be
368 controlled by the <<strip>> and <<discard>> fields of the
369 <<bfd_link_info>> structure.
371 The local symbols of the input files will not have been
372 entered into the linker hash table. The <<_bfd_final_link>>
373 routine must consider each input file and include the symbols
374 in the output file. It may be convenient to do this when
375 looking through the <<link_order>> structures, or it may be
376 done by stepping through the <<input_bfds>> list.
378 The <<_bfd_final_link>> routine must also traverse the global
379 hash table to gather all the externally visible symbols. It
380 is possible that most of the externally visible symbols may be
381 written out when considering the symbols of each input file,
382 but it is still necessary to traverse the hash table since the
383 linker script may have defined some symbols that are not in
384 any of the input files.
386 The <<strip>> field of the <<bfd_link_info>> structure
387 controls which symbols are written out. The possible values
388 are listed in <<bfdlink.h>>. If the value is <<strip_some>>,
389 then the <<keep_hash>> field of the <<bfd_link_info>>
390 structure is a hash table of symbols to keep; each symbol
391 should be looked up in this hash table, and only symbols which
392 are present should be included in the output file.
394 If the <<strip>> field of the <<bfd_link_info>> structure
395 permits local symbols to be written out, the <<discard>> field
396 is used to further controls which local symbols are included
397 in the output file. If the value is <<discard_l>>, then all
398 local symbols which begin with a certain prefix are discarded;
399 this is controlled by the <<bfd_is_local_label_name>> entry point.
401 The a.out backend handles symbols by calling
402 <<aout_link_write_symbols>> on each input BFD and then
403 traversing the global hash table with the function
404 <<aout_link_write_other_symbol>>. It builds a string table
405 while writing out the symbols, which is written to the output
406 file at the end of <<NAME(aout,final_link)>>.
409 static boolean generic_link_read_symbols
410 PARAMS ((bfd *));
411 static boolean generic_link_add_symbols
412 PARAMS ((bfd *, struct bfd_link_info *, boolean collect));
413 static boolean generic_link_add_object_symbols
414 PARAMS ((bfd *, struct bfd_link_info *, boolean collect));
415 static boolean generic_link_check_archive_element_no_collect
416 PARAMS ((bfd *, struct bfd_link_info *, boolean *pneeded));
417 static boolean generic_link_check_archive_element_collect
418 PARAMS ((bfd *, struct bfd_link_info *, boolean *pneeded));
419 static boolean generic_link_check_archive_element
420 PARAMS ((bfd *, struct bfd_link_info *, boolean *pneeded, boolean collect));
421 static boolean generic_link_add_symbol_list
422 PARAMS ((bfd *, struct bfd_link_info *, bfd_size_type count, asymbol **,
423 boolean collect));
424 static bfd *hash_entry_bfd PARAMS ((struct bfd_link_hash_entry *));
425 static void set_symbol_from_hash
426 PARAMS ((asymbol *, struct bfd_link_hash_entry *));
427 static boolean generic_add_output_symbol
428 PARAMS ((bfd *, size_t *psymalloc, asymbol *));
429 static boolean default_fill_link_order
430 PARAMS ((bfd *, struct bfd_link_info *, asection *,
431 struct bfd_link_order *));
432 static boolean default_indirect_link_order
433 PARAMS ((bfd *, struct bfd_link_info *, asection *,
434 struct bfd_link_order *, boolean));
436 /* The link hash table structure is defined in bfdlink.h. It provides
437 a base hash table which the backend specific hash tables are built
438 upon. */
440 /* Routine to create an entry in the link hash table. */
442 struct bfd_hash_entry *
443 _bfd_link_hash_newfunc (entry, table, string)
444 struct bfd_hash_entry *entry;
445 struct bfd_hash_table *table;
446 const char *string;
448 struct bfd_link_hash_entry *ret = (struct bfd_link_hash_entry *) entry;
450 /* Allocate the structure if it has not already been allocated by a
451 subclass. */
452 if (ret == (struct bfd_link_hash_entry *) NULL)
453 ret = ((struct bfd_link_hash_entry *)
454 bfd_hash_allocate (table, sizeof (struct bfd_link_hash_entry)));
455 if (ret == (struct bfd_link_hash_entry *) NULL)
456 return NULL;
458 /* Call the allocation method of the superclass. */
459 ret = ((struct bfd_link_hash_entry *)
460 bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));
462 if (ret)
464 /* Initialize the local fields. */
465 ret->type = bfd_link_hash_new;
466 ret->next = NULL;
469 return (struct bfd_hash_entry *) ret;
472 /* Initialize a link hash table. The BFD argument is the one
473 responsible for creating this table. */
475 boolean
476 _bfd_link_hash_table_init (table, abfd, newfunc)
477 struct bfd_link_hash_table *table;
478 bfd *abfd;
479 struct bfd_hash_entry *(*newfunc) PARAMS ((struct bfd_hash_entry *,
480 struct bfd_hash_table *,
481 const char *));
483 table->creator = abfd->xvec;
484 table->undefs = NULL;
485 table->undefs_tail = NULL;
486 return bfd_hash_table_init (&table->table, newfunc);
489 /* Look up a symbol in a link hash table. If follow is true, we
490 follow bfd_link_hash_indirect and bfd_link_hash_warning links to
491 the real symbol. */
493 struct bfd_link_hash_entry *
494 bfd_link_hash_lookup (table, string, create, copy, follow)
495 struct bfd_link_hash_table *table;
496 const char *string;
497 boolean create;
498 boolean copy;
499 boolean follow;
501 struct bfd_link_hash_entry *ret;
503 ret = ((struct bfd_link_hash_entry *)
504 bfd_hash_lookup (&table->table, string, create, copy));
506 if (follow && ret != (struct bfd_link_hash_entry *) NULL)
508 while (ret->type == bfd_link_hash_indirect
509 || ret->type == bfd_link_hash_warning)
510 ret = ret->u.i.link;
513 return ret;
516 /* Look up a symbol in the main linker hash table if the symbol might
517 be wrapped. This should only be used for references to an
518 undefined symbol, not for definitions of a symbol. */
520 struct bfd_link_hash_entry *
521 bfd_wrapped_link_hash_lookup (abfd, info, string, create, copy, follow)
522 bfd *abfd;
523 struct bfd_link_info *info;
524 const char *string;
525 boolean create;
526 boolean copy;
527 boolean follow;
529 if (info->wrap_hash != NULL)
531 const char *l;
533 l = string;
534 if (*l == bfd_get_symbol_leading_char (abfd))
535 ++l;
537 #undef WRAP
538 #define WRAP "__wrap_"
540 if (bfd_hash_lookup (info->wrap_hash, l, false, false) != NULL)
542 char *n;
543 struct bfd_link_hash_entry *h;
545 /* This symbol is being wrapped. We want to replace all
546 references to SYM with references to __wrap_SYM. */
548 n = (char *) bfd_malloc (strlen (l) + sizeof WRAP + 1);
549 if (n == NULL)
550 return NULL;
552 /* Note that symbol_leading_char may be '\0'. */
553 n[0] = bfd_get_symbol_leading_char (abfd);
554 n[1] = '\0';
555 strcat (n, WRAP);
556 strcat (n, l);
557 h = bfd_link_hash_lookup (info->hash, n, create, true, follow);
558 free (n);
559 return h;
562 #undef WRAP
564 #undef REAL
565 #define REAL "__real_"
567 if (*l == '_'
568 && strncmp (l, REAL, sizeof REAL - 1) == 0
569 && bfd_hash_lookup (info->wrap_hash, l + sizeof REAL - 1,
570 false, false) != NULL)
572 char *n;
573 struct bfd_link_hash_entry *h;
575 /* This is a reference to __real_SYM, where SYM is being
576 wrapped. We want to replace all references to __real_SYM
577 with references to SYM. */
579 n = (char *) bfd_malloc (strlen (l + sizeof REAL - 1) + 2);
580 if (n == NULL)
581 return NULL;
583 /* Note that symbol_leading_char may be '\0'. */
584 n[0] = bfd_get_symbol_leading_char (abfd);
585 n[1] = '\0';
586 strcat (n, l + sizeof REAL - 1);
587 h = bfd_link_hash_lookup (info->hash, n, create, true, follow);
588 free (n);
589 return h;
592 #undef REAL
595 return bfd_link_hash_lookup (info->hash, string, create, copy, follow);
598 /* Traverse a generic link hash table. The only reason this is not a
599 macro is to do better type checking. This code presumes that an
600 argument passed as a struct bfd_hash_entry * may be caught as a
601 struct bfd_link_hash_entry * with no explicit cast required on the
602 call. */
604 void
605 bfd_link_hash_traverse (table, func, info)
606 struct bfd_link_hash_table *table;
607 boolean (*func) PARAMS ((struct bfd_link_hash_entry *, PTR));
608 PTR info;
610 bfd_hash_traverse (&table->table,
611 ((boolean (*) PARAMS ((struct bfd_hash_entry *, PTR)))
612 func),
613 info);
616 /* Add a symbol to the linker hash table undefs list. */
618 INLINE void
619 bfd_link_add_undef (table, h)
620 struct bfd_link_hash_table *table;
621 struct bfd_link_hash_entry *h;
623 BFD_ASSERT (h->next == NULL);
624 if (table->undefs_tail != (struct bfd_link_hash_entry *) NULL)
625 table->undefs_tail->next = h;
626 if (table->undefs == (struct bfd_link_hash_entry *) NULL)
627 table->undefs = h;
628 table->undefs_tail = h;
631 /* Routine to create an entry in an generic link hash table. */
633 struct bfd_hash_entry *
634 _bfd_generic_link_hash_newfunc (entry, table, string)
635 struct bfd_hash_entry *entry;
636 struct bfd_hash_table *table;
637 const char *string;
639 struct generic_link_hash_entry *ret =
640 (struct generic_link_hash_entry *) entry;
642 /* Allocate the structure if it has not already been allocated by a
643 subclass. */
644 if (ret == (struct generic_link_hash_entry *) NULL)
645 ret = ((struct generic_link_hash_entry *)
646 bfd_hash_allocate (table, sizeof (struct generic_link_hash_entry)));
647 if (ret == (struct generic_link_hash_entry *) NULL)
648 return NULL;
650 /* Call the allocation method of the superclass. */
651 ret = ((struct generic_link_hash_entry *)
652 _bfd_link_hash_newfunc ((struct bfd_hash_entry *) ret,
653 table, string));
655 if (ret)
657 /* Set local fields. */
658 ret->written = false;
659 ret->sym = NULL;
662 return (struct bfd_hash_entry *) ret;
665 /* Create an generic link hash table. */
667 struct bfd_link_hash_table *
668 _bfd_generic_link_hash_table_create (abfd)
669 bfd *abfd;
671 struct generic_link_hash_table *ret;
673 ret = ((struct generic_link_hash_table *)
674 bfd_alloc (abfd, sizeof (struct generic_link_hash_table)));
675 if (ret == NULL)
676 return (struct bfd_link_hash_table *) NULL;
677 if (! _bfd_link_hash_table_init (&ret->root, abfd,
678 _bfd_generic_link_hash_newfunc))
680 free (ret);
681 return (struct bfd_link_hash_table *) NULL;
683 return &ret->root;
686 /* Grab the symbols for an object file when doing a generic link. We
687 store the symbols in the outsymbols field. We need to keep them
688 around for the entire link to ensure that we only read them once.
689 If we read them multiple times, we might wind up with relocs and
690 the hash table pointing to different instances of the symbol
691 structure. */
693 static boolean
694 generic_link_read_symbols (abfd)
695 bfd *abfd;
697 if (bfd_get_outsymbols (abfd) == (asymbol **) NULL)
699 long symsize;
700 long symcount;
702 symsize = bfd_get_symtab_upper_bound (abfd);
703 if (symsize < 0)
704 return false;
705 bfd_get_outsymbols (abfd) = (asymbol **) bfd_alloc (abfd, symsize);
706 if (bfd_get_outsymbols (abfd) == NULL && symsize != 0)
707 return false;
708 symcount = bfd_canonicalize_symtab (abfd, bfd_get_outsymbols (abfd));
709 if (symcount < 0)
710 return false;
711 bfd_get_symcount (abfd) = symcount;
714 return true;
717 /* Generic function to add symbols to from an object file to the
718 global hash table. This version does not automatically collect
719 constructors by name. */
721 boolean
722 _bfd_generic_link_add_symbols (abfd, info)
723 bfd *abfd;
724 struct bfd_link_info *info;
726 return generic_link_add_symbols (abfd, info, false);
729 /* Generic function to add symbols from an object file to the global
730 hash table. This version automatically collects constructors by
731 name, as the collect2 program does. It should be used for any
732 target which does not provide some other mechanism for setting up
733 constructors and destructors; these are approximately those targets
734 for which gcc uses collect2 and do not support stabs. */
736 boolean
737 _bfd_generic_link_add_symbols_collect (abfd, info)
738 bfd *abfd;
739 struct bfd_link_info *info;
741 return generic_link_add_symbols (abfd, info, true);
744 /* Add symbols from an object file to the global hash table. */
746 static boolean
747 generic_link_add_symbols (abfd, info, collect)
748 bfd *abfd;
749 struct bfd_link_info *info;
750 boolean collect;
752 boolean ret;
754 switch (bfd_get_format (abfd))
756 case bfd_object:
757 ret = generic_link_add_object_symbols (abfd, info, collect);
758 break;
759 case bfd_archive:
760 ret = (_bfd_generic_link_add_archive_symbols
761 (abfd, info,
762 (collect
763 ? generic_link_check_archive_element_collect
764 : generic_link_check_archive_element_no_collect)));
765 break;
766 default:
767 bfd_set_error (bfd_error_wrong_format);
768 ret = false;
771 return ret;
774 /* Add symbols from an object file to the global hash table. */
776 static boolean
777 generic_link_add_object_symbols (abfd, info, collect)
778 bfd *abfd;
779 struct bfd_link_info *info;
780 boolean collect;
782 if (! generic_link_read_symbols (abfd))
783 return false;
784 return generic_link_add_symbol_list (abfd, info,
785 _bfd_generic_link_get_symcount (abfd),
786 _bfd_generic_link_get_symbols (abfd),
787 collect);
790 /* We build a hash table of all symbols defined in an archive. */
792 /* An archive symbol may be defined by multiple archive elements.
793 This linked list is used to hold the elements. */
795 struct archive_list
797 struct archive_list *next;
798 int indx;
801 /* An entry in an archive hash table. */
803 struct archive_hash_entry
805 struct bfd_hash_entry root;
806 /* Where the symbol is defined. */
807 struct archive_list *defs;
810 /* An archive hash table itself. */
812 struct archive_hash_table
814 struct bfd_hash_table table;
817 static struct bfd_hash_entry *archive_hash_newfunc
818 PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *));
819 static boolean archive_hash_table_init
820 PARAMS ((struct archive_hash_table *,
821 struct bfd_hash_entry *(*) (struct bfd_hash_entry *,
822 struct bfd_hash_table *,
823 const char *)));
825 /* Create a new entry for an archive hash table. */
827 static struct bfd_hash_entry *
828 archive_hash_newfunc (entry, table, string)
829 struct bfd_hash_entry *entry;
830 struct bfd_hash_table *table;
831 const char *string;
833 struct archive_hash_entry *ret = (struct archive_hash_entry *) entry;
835 /* Allocate the structure if it has not already been allocated by a
836 subclass. */
837 if (ret == (struct archive_hash_entry *) NULL)
838 ret = ((struct archive_hash_entry *)
839 bfd_hash_allocate (table, sizeof (struct archive_hash_entry)));
840 if (ret == (struct archive_hash_entry *) NULL)
841 return NULL;
843 /* Call the allocation method of the superclass. */
844 ret = ((struct archive_hash_entry *)
845 bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));
847 if (ret)
849 /* Initialize the local fields. */
850 ret->defs = (struct archive_list *) NULL;
853 return (struct bfd_hash_entry *) ret;
856 /* Initialize an archive hash table. */
858 static boolean
859 archive_hash_table_init (table, newfunc)
860 struct archive_hash_table *table;
861 struct bfd_hash_entry *(*newfunc) PARAMS ((struct bfd_hash_entry *,
862 struct bfd_hash_table *,
863 const char *));
865 return bfd_hash_table_init (&table->table, newfunc);
868 /* Look up an entry in an archive hash table. */
870 #define archive_hash_lookup(t, string, create, copy) \
871 ((struct archive_hash_entry *) \
872 bfd_hash_lookup (&(t)->table, (string), (create), (copy)))
874 /* Allocate space in an archive hash table. */
876 #define archive_hash_allocate(t, size) bfd_hash_allocate (&(t)->table, (size))
878 /* Free an archive hash table. */
880 #define archive_hash_table_free(t) bfd_hash_table_free (&(t)->table)
882 /* Generic function to add symbols from an archive file to the global
883 hash file. This function presumes that the archive symbol table
884 has already been read in (this is normally done by the
885 bfd_check_format entry point). It looks through the undefined and
886 common symbols and searches the archive symbol table for them. If
887 it finds an entry, it includes the associated object file in the
888 link.
890 The old linker looked through the archive symbol table for
891 undefined symbols. We do it the other way around, looking through
892 undefined symbols for symbols defined in the archive. The
893 advantage of the newer scheme is that we only have to look through
894 the list of undefined symbols once, whereas the old method had to
895 re-search the symbol table each time a new object file was added.
897 The CHECKFN argument is used to see if an object file should be
898 included. CHECKFN should set *PNEEDED to true if the object file
899 should be included, and must also call the bfd_link_info
900 add_archive_element callback function and handle adding the symbols
901 to the global hash table. CHECKFN should only return false if some
902 sort of error occurs.
904 For some formats, such as a.out, it is possible to look through an
905 object file but not actually include it in the link. The
906 archive_pass field in a BFD is used to avoid checking the symbols
907 of an object files too many times. When an object is included in
908 the link, archive_pass is set to -1. If an object is scanned but
909 not included, archive_pass is set to the pass number. The pass
910 number is incremented each time a new object file is included. The
911 pass number is used because when a new object file is included it
912 may create new undefined symbols which cause a previously examined
913 object file to be included. */
915 boolean
916 _bfd_generic_link_add_archive_symbols (abfd, info, checkfn)
917 bfd *abfd;
918 struct bfd_link_info *info;
919 boolean (*checkfn) PARAMS ((bfd *, struct bfd_link_info *,
920 boolean *pneeded));
922 carsym *arsyms;
923 carsym *arsym_end;
924 register carsym *arsym;
925 int pass;
926 struct archive_hash_table arsym_hash;
927 int indx;
928 struct bfd_link_hash_entry **pundef;
930 if (! bfd_has_map (abfd))
932 /* An empty archive is a special case. */
933 if (bfd_openr_next_archived_file (abfd, (bfd *) NULL) == NULL)
934 return true;
935 bfd_set_error (bfd_error_no_armap);
936 return false;
939 arsyms = bfd_ardata (abfd)->symdefs;
940 arsym_end = arsyms + bfd_ardata (abfd)->symdef_count;
942 /* In order to quickly determine whether an symbol is defined in
943 this archive, we build a hash table of the symbols. */
944 if (! archive_hash_table_init (&arsym_hash, archive_hash_newfunc))
945 return false;
946 for (arsym = arsyms, indx = 0; arsym < arsym_end; arsym++, indx++)
948 struct archive_hash_entry *arh;
949 struct archive_list *l, **pp;
951 arh = archive_hash_lookup (&arsym_hash, arsym->name, true, false);
952 if (arh == (struct archive_hash_entry *) NULL)
953 goto error_return;
954 l = ((struct archive_list *)
955 archive_hash_allocate (&arsym_hash, sizeof (struct archive_list)));
956 if (l == NULL)
957 goto error_return;
958 l->indx = indx;
959 for (pp = &arh->defs;
960 *pp != (struct archive_list *) NULL;
961 pp = &(*pp)->next)
963 *pp = l;
964 l->next = NULL;
967 /* The archive_pass field in the archive itself is used to
968 initialize PASS, sine we may search the same archive multiple
969 times. */
970 pass = abfd->archive_pass + 1;
972 /* New undefined symbols are added to the end of the list, so we
973 only need to look through it once. */
974 pundef = &info->hash->undefs;
975 while (*pundef != (struct bfd_link_hash_entry *) NULL)
977 struct bfd_link_hash_entry *h;
978 struct archive_hash_entry *arh;
979 struct archive_list *l;
981 h = *pundef;
983 /* When a symbol is defined, it is not necessarily removed from
984 the list. */
985 if (h->type != bfd_link_hash_undefined
986 && h->type != bfd_link_hash_common)
988 /* Remove this entry from the list, for general cleanliness
989 and because we are going to look through the list again
990 if we search any more libraries. We can't remove the
991 entry if it is the tail, because that would lose any
992 entries we add to the list later on (it would also cause
993 us to lose track of whether the symbol has been
994 referenced). */
995 if (*pundef != info->hash->undefs_tail)
996 *pundef = (*pundef)->next;
997 else
998 pundef = &(*pundef)->next;
999 continue;
1002 /* Look for this symbol in the archive symbol map. */
1003 arh = archive_hash_lookup (&arsym_hash, h->root.string, false, false);
1004 if (arh == (struct archive_hash_entry *) NULL)
1006 /* If we haven't found the exact symbol we're looking for,
1007 let's look for its import thunk */
1008 if (info->pei386_auto_import)
1010 char *buf = alloca (strlen (h->root.string) + 10);
1011 sprintf (buf, "__imp_%s", h->root.string);
1012 arh = archive_hash_lookup (&arsym_hash, buf, false, false);
1014 if (arh == (struct archive_hash_entry *) NULL)
1016 pundef = &(*pundef)->next;
1017 continue;
1020 /* Look at all the objects which define this symbol. */
1021 for (l = arh->defs; l != (struct archive_list *) NULL; l = l->next)
1023 bfd *element;
1024 boolean needed;
1026 /* If the symbol has gotten defined along the way, quit. */
1027 if (h->type != bfd_link_hash_undefined
1028 && h->type != bfd_link_hash_common)
1029 break;
1031 element = bfd_get_elt_at_index (abfd, l->indx);
1032 if (element == (bfd *) NULL)
1033 goto error_return;
1035 /* If we've already included this element, or if we've
1036 already checked it on this pass, continue. */
1037 if (element->archive_pass == -1
1038 || element->archive_pass == pass)
1039 continue;
1041 /* If we can't figure this element out, just ignore it. */
1042 if (! bfd_check_format (element, bfd_object))
1044 element->archive_pass = -1;
1045 continue;
1048 /* CHECKFN will see if this element should be included, and
1049 go ahead and include it if appropriate. */
1050 if (! (*checkfn) (element, info, &needed))
1051 goto error_return;
1053 if (! needed)
1054 element->archive_pass = pass;
1055 else
1057 element->archive_pass = -1;
1059 /* Increment the pass count to show that we may need to
1060 recheck object files which were already checked. */
1061 ++pass;
1065 pundef = &(*pundef)->next;
1068 archive_hash_table_free (&arsym_hash);
1070 /* Save PASS in case we are called again. */
1071 abfd->archive_pass = pass;
1073 return true;
1075 error_return:
1076 archive_hash_table_free (&arsym_hash);
1077 return false;
1080 /* See if we should include an archive element. This version is used
1081 when we do not want to automatically collect constructors based on
1082 the symbol name, presumably because we have some other mechanism
1083 for finding them. */
1085 static boolean
1086 generic_link_check_archive_element_no_collect (abfd, info, pneeded)
1087 bfd *abfd;
1088 struct bfd_link_info *info;
1089 boolean *pneeded;
1091 return generic_link_check_archive_element (abfd, info, pneeded, false);
1094 /* See if we should include an archive element. This version is used
1095 when we want to automatically collect constructors based on the
1096 symbol name, as collect2 does. */
1098 static boolean
1099 generic_link_check_archive_element_collect (abfd, info, pneeded)
1100 bfd *abfd;
1101 struct bfd_link_info *info;
1102 boolean *pneeded;
1104 return generic_link_check_archive_element (abfd, info, pneeded, true);
1107 /* See if we should include an archive element. Optionally collect
1108 constructors. */
1110 static boolean
1111 generic_link_check_archive_element (abfd, info, pneeded, collect)
1112 bfd *abfd;
1113 struct bfd_link_info *info;
1114 boolean *pneeded;
1115 boolean collect;
1117 asymbol **pp, **ppend;
1119 *pneeded = false;
1121 if (! generic_link_read_symbols (abfd))
1122 return false;
1124 pp = _bfd_generic_link_get_symbols (abfd);
1125 ppend = pp + _bfd_generic_link_get_symcount (abfd);
1126 for (; pp < ppend; pp++)
1128 asymbol *p;
1129 struct bfd_link_hash_entry *h;
1131 p = *pp;
1133 /* We are only interested in globally visible symbols. */
1134 if (! bfd_is_com_section (p->section)
1135 && (p->flags & (BSF_GLOBAL | BSF_INDIRECT | BSF_WEAK)) == 0)
1136 continue;
1138 /* We are only interested if we know something about this
1139 symbol, and it is undefined or common. An undefined weak
1140 symbol (type bfd_link_hash_undefweak) is not considered to be
1141 a reference when pulling files out of an archive. See the
1142 SVR4 ABI, p. 4-27. */
1143 h = bfd_link_hash_lookup (info->hash, bfd_asymbol_name (p), false,
1144 false, true);
1145 if (h == (struct bfd_link_hash_entry *) NULL
1146 || (h->type != bfd_link_hash_undefined
1147 && h->type != bfd_link_hash_common))
1148 continue;
1150 /* P is a symbol we are looking for. */
1152 if (! bfd_is_com_section (p->section))
1154 bfd_size_type symcount;
1155 asymbol **symbols;
1157 /* This object file defines this symbol, so pull it in. */
1158 if (! (*info->callbacks->add_archive_element) (info, abfd,
1159 bfd_asymbol_name (p)))
1160 return false;
1161 symcount = _bfd_generic_link_get_symcount (abfd);
1162 symbols = _bfd_generic_link_get_symbols (abfd);
1163 if (! generic_link_add_symbol_list (abfd, info, symcount,
1164 symbols, collect))
1165 return false;
1166 *pneeded = true;
1167 return true;
1170 /* P is a common symbol. */
1172 if (h->type == bfd_link_hash_undefined)
1174 bfd *symbfd;
1175 bfd_vma size;
1176 unsigned int power;
1178 symbfd = h->u.undef.abfd;
1179 if (symbfd == (bfd *) NULL)
1181 /* This symbol was created as undefined from outside
1182 BFD. We assume that we should link in the object
1183 file. This is for the -u option in the linker. */
1184 if (! (*info->callbacks->add_archive_element)
1185 (info, abfd, bfd_asymbol_name (p)))
1186 return false;
1187 *pneeded = true;
1188 return true;
1191 /* Turn the symbol into a common symbol but do not link in
1192 the object file. This is how a.out works. Object
1193 formats that require different semantics must implement
1194 this function differently. This symbol is already on the
1195 undefs list. We add the section to a common section
1196 attached to symbfd to ensure that it is in a BFD which
1197 will be linked in. */
1198 h->type = bfd_link_hash_common;
1199 h->u.c.p =
1200 ((struct bfd_link_hash_common_entry *)
1201 bfd_hash_allocate (&info->hash->table,
1202 sizeof (struct bfd_link_hash_common_entry)));
1203 if (h->u.c.p == NULL)
1204 return false;
1206 size = bfd_asymbol_value (p);
1207 h->u.c.size = size;
1209 power = bfd_log2 (size);
1210 if (power > 4)
1211 power = 4;
1212 h->u.c.p->alignment_power = power;
1214 if (p->section == bfd_com_section_ptr)
1215 h->u.c.p->section = bfd_make_section_old_way (symbfd, "COMMON");
1216 else
1217 h->u.c.p->section = bfd_make_section_old_way (symbfd,
1218 p->section->name);
1219 h->u.c.p->section->flags = SEC_ALLOC;
1221 else
1223 /* Adjust the size of the common symbol if necessary. This
1224 is how a.out works. Object formats that require
1225 different semantics must implement this function
1226 differently. */
1227 if (bfd_asymbol_value (p) > h->u.c.size)
1228 h->u.c.size = bfd_asymbol_value (p);
1232 /* This archive element is not needed. */
1233 return true;
1236 /* Add the symbols from an object file to the global hash table. ABFD
1237 is the object file. INFO is the linker information. SYMBOL_COUNT
1238 is the number of symbols. SYMBOLS is the list of symbols. COLLECT
1239 is true if constructors should be automatically collected by name
1240 as is done by collect2. */
1242 static boolean
1243 generic_link_add_symbol_list (abfd, info, symbol_count, symbols, collect)
1244 bfd *abfd;
1245 struct bfd_link_info *info;
1246 bfd_size_type symbol_count;
1247 asymbol **symbols;
1248 boolean collect;
1250 asymbol **pp, **ppend;
1252 pp = symbols;
1253 ppend = symbols + symbol_count;
1254 for (; pp < ppend; pp++)
1256 asymbol *p;
1258 p = *pp;
1260 if ((p->flags & (BSF_INDIRECT
1261 | BSF_WARNING
1262 | BSF_GLOBAL
1263 | BSF_CONSTRUCTOR
1264 | BSF_WEAK)) != 0
1265 || bfd_is_und_section (bfd_get_section (p))
1266 || bfd_is_com_section (bfd_get_section (p))
1267 || bfd_is_ind_section (bfd_get_section (p)))
1269 const char *name;
1270 const char *string;
1271 struct generic_link_hash_entry *h;
1273 name = bfd_asymbol_name (p);
1274 if (((p->flags & BSF_INDIRECT) != 0
1275 || bfd_is_ind_section (p->section))
1276 && pp + 1 < ppend)
1278 pp++;
1279 string = bfd_asymbol_name (*pp);
1281 else if ((p->flags & BSF_WARNING) != 0
1282 && pp + 1 < ppend)
1284 /* The name of P is actually the warning string, and the
1285 next symbol is the one to warn about. */
1286 string = name;
1287 pp++;
1288 name = bfd_asymbol_name (*pp);
1290 else
1291 string = NULL;
1293 h = NULL;
1294 if (! (_bfd_generic_link_add_one_symbol
1295 (info, abfd, name, p->flags, bfd_get_section (p),
1296 p->value, string, false, collect,
1297 (struct bfd_link_hash_entry **) &h)))
1298 return false;
1300 /* If this is a constructor symbol, and the linker didn't do
1301 anything with it, then we want to just pass the symbol
1302 through to the output file. This will happen when
1303 linking with -r. */
1304 if ((p->flags & BSF_CONSTRUCTOR) != 0
1305 && (h == NULL || h->root.type == bfd_link_hash_new))
1307 p->udata.p = NULL;
1308 continue;
1311 /* Save the BFD symbol so that we don't lose any backend
1312 specific information that may be attached to it. We only
1313 want this one if it gives more information than the
1314 existing one; we don't want to replace a defined symbol
1315 with an undefined one. This routine may be called with a
1316 hash table other than the generic hash table, so we only
1317 do this if we are certain that the hash table is a
1318 generic one. */
1319 if (info->hash->creator == abfd->xvec)
1321 if (h->sym == (asymbol *) NULL
1322 || (! bfd_is_und_section (bfd_get_section (p))
1323 && (! bfd_is_com_section (bfd_get_section (p))
1324 || bfd_is_und_section (bfd_get_section (h->sym)))))
1326 h->sym = p;
1327 /* BSF_OLD_COMMON is a hack to support COFF reloc
1328 reading, and it should go away when the COFF
1329 linker is switched to the new version. */
1330 if (bfd_is_com_section (bfd_get_section (p)))
1331 p->flags |= BSF_OLD_COMMON;
1335 /* Store a back pointer from the symbol to the hash
1336 table entry for the benefit of relaxation code until
1337 it gets rewritten to not use asymbol structures.
1338 Setting this is also used to check whether these
1339 symbols were set up by the generic linker. */
1340 p->udata.p = (PTR) h;
1344 return true;
1347 /* We use a state table to deal with adding symbols from an object
1348 file. The first index into the state table describes the symbol
1349 from the object file. The second index into the state table is the
1350 type of the symbol in the hash table. */
1352 /* The symbol from the object file is turned into one of these row
1353 values. */
1355 enum link_row
1357 UNDEF_ROW, /* Undefined. */
1358 UNDEFW_ROW, /* Weak undefined. */
1359 DEF_ROW, /* Defined. */
1360 DEFW_ROW, /* Weak defined. */
1361 COMMON_ROW, /* Common. */
1362 INDR_ROW, /* Indirect. */
1363 WARN_ROW, /* Warning. */
1364 SET_ROW /* Member of set. */
1367 /* apparently needed for Hitachi 3050R(HI-UX/WE2)? */
1368 #undef FAIL
1370 /* The actions to take in the state table. */
1372 enum link_action
1374 FAIL, /* Abort. */
1375 UND, /* Mark symbol undefined. */
1376 WEAK, /* Mark symbol weak undefined. */
1377 DEF, /* Mark symbol defined. */
1378 DEFW, /* Mark symbol weak defined. */
1379 COM, /* Mark symbol common. */
1380 REF, /* Mark defined symbol referenced. */
1381 CREF, /* Possibly warn about common reference to defined symbol. */
1382 CDEF, /* Define existing common symbol. */
1383 NOACT, /* No action. */
1384 BIG, /* Mark symbol common using largest size. */
1385 MDEF, /* Multiple definition error. */
1386 MIND, /* Multiple indirect symbols. */
1387 IND, /* Make indirect symbol. */
1388 CIND, /* Make indirect symbol from existing common symbol. */
1389 SET, /* Add value to set. */
1390 MWARN, /* Make warning symbol. */
1391 WARN, /* Issue warning. */
1392 CWARN, /* Warn if referenced, else MWARN. */
1393 CYCLE, /* Repeat with symbol pointed to. */
1394 REFC, /* Mark indirect symbol referenced and then CYCLE. */
1395 WARNC /* Issue warning and then CYCLE. */
1398 /* The state table itself. The first index is a link_row and the
1399 second index is a bfd_link_hash_type. */
1401 static const enum link_action link_action[8][8] =
1403 /* current\prev new undef undefw def defw com indr warn */
1404 /* UNDEF_ROW */ {UND, NOACT, UND, REF, REF, NOACT, REFC, WARNC },
1405 /* UNDEFW_ROW */ {WEAK, NOACT, NOACT, REF, REF, NOACT, REFC, WARNC },
1406 /* DEF_ROW */ {DEF, DEF, DEF, MDEF, DEF, CDEF, MDEF, CYCLE },
1407 /* DEFW_ROW */ {DEFW, DEFW, DEFW, NOACT, NOACT, NOACT, NOACT, CYCLE },
1408 /* COMMON_ROW */ {COM, COM, COM, CREF, CREF, BIG, REFC, WARNC },
1409 /* INDR_ROW */ {IND, IND, IND, MDEF, IND, CIND, MIND, CYCLE },
1410 /* WARN_ROW */ {MWARN, WARN, WARN, CWARN, CWARN, WARN, CWARN, MWARN },
1411 /* SET_ROW */ {SET, SET, SET, SET, SET, SET, CYCLE, CYCLE }
1414 /* Most of the entries in the LINK_ACTION table are straightforward,
1415 but a few are somewhat subtle.
1417 A reference to an indirect symbol (UNDEF_ROW/indr or
1418 UNDEFW_ROW/indr) is counted as a reference both to the indirect
1419 symbol and to the symbol the indirect symbol points to.
1421 A reference to a warning symbol (UNDEF_ROW/warn or UNDEFW_ROW/warn)
1422 causes the warning to be issued.
1424 A common definition of an indirect symbol (COMMON_ROW/indr) is
1425 treated as a multiple definition error. Likewise for an indirect
1426 definition of a common symbol (INDR_ROW/com).
1428 An indirect definition of a warning (INDR_ROW/warn) does not cause
1429 the warning to be issued.
1431 If a warning is created for an indirect symbol (WARN_ROW/indr) no
1432 warning is created for the symbol the indirect symbol points to.
1434 Adding an entry to a set does not count as a reference to a set,
1435 and no warning is issued (SET_ROW/warn). */
1437 /* Return the BFD in which a hash entry has been defined, if known. */
1439 static bfd *
1440 hash_entry_bfd (h)
1441 struct bfd_link_hash_entry *h;
1443 while (h->type == bfd_link_hash_warning)
1444 h = h->u.i.link;
1445 switch (h->type)
1447 default:
1448 return NULL;
1449 case bfd_link_hash_undefined:
1450 case bfd_link_hash_undefweak:
1451 return h->u.undef.abfd;
1452 case bfd_link_hash_defined:
1453 case bfd_link_hash_defweak:
1454 return h->u.def.section->owner;
1455 case bfd_link_hash_common:
1456 return h->u.c.p->section->owner;
1458 /*NOTREACHED*/
1461 /* Add a symbol to the global hash table.
1462 ABFD is the BFD the symbol comes from.
1463 NAME is the name of the symbol.
1464 FLAGS is the BSF_* bits associated with the symbol.
1465 SECTION is the section in which the symbol is defined; this may be
1466 bfd_und_section_ptr or bfd_com_section_ptr.
1467 VALUE is the value of the symbol, relative to the section.
1468 STRING is used for either an indirect symbol, in which case it is
1469 the name of the symbol to indirect to, or a warning symbol, in
1470 which case it is the warning string.
1471 COPY is true if NAME or STRING must be copied into locally
1472 allocated memory if they need to be saved.
1473 COLLECT is true if we should automatically collect gcc constructor
1474 or destructor names as collect2 does.
1475 HASHP, if not NULL, is a place to store the created hash table
1476 entry; if *HASHP is not NULL, the caller has already looked up
1477 the hash table entry, and stored it in *HASHP. */
1479 boolean
1480 _bfd_generic_link_add_one_symbol (info, abfd, name, flags, section, value,
1481 string, copy, collect, hashp)
1482 struct bfd_link_info *info;
1483 bfd *abfd;
1484 const char *name;
1485 flagword flags;
1486 asection *section;
1487 bfd_vma value;
1488 const char *string;
1489 boolean copy;
1490 boolean collect;
1491 struct bfd_link_hash_entry **hashp;
1493 enum link_row row;
1494 struct bfd_link_hash_entry *h;
1495 boolean cycle;
1497 if (bfd_is_ind_section (section)
1498 || (flags & BSF_INDIRECT) != 0)
1499 row = INDR_ROW;
1500 else if ((flags & BSF_WARNING) != 0)
1501 row = WARN_ROW;
1502 else if ((flags & BSF_CONSTRUCTOR) != 0)
1503 row = SET_ROW;
1504 else if (bfd_is_und_section (section))
1506 if ((flags & BSF_WEAK) != 0)
1507 row = UNDEFW_ROW;
1508 else
1509 row = UNDEF_ROW;
1511 else if ((flags & BSF_WEAK) != 0)
1512 row = DEFW_ROW;
1513 else if (bfd_is_com_section (section))
1514 row = COMMON_ROW;
1515 else
1516 row = DEF_ROW;
1518 if (hashp != NULL && *hashp != NULL)
1519 h = *hashp;
1520 else
1522 if (row == UNDEF_ROW || row == UNDEFW_ROW)
1523 h = bfd_wrapped_link_hash_lookup (abfd, info, name, true, copy, false);
1524 else
1525 h = bfd_link_hash_lookup (info->hash, name, true, copy, false);
1526 if (h == NULL)
1528 if (hashp != NULL)
1529 *hashp = NULL;
1530 return false;
1534 if (info->notice_all
1535 || (info->notice_hash != (struct bfd_hash_table *) NULL
1536 && (bfd_hash_lookup (info->notice_hash, name, false, false)
1537 != (struct bfd_hash_entry *) NULL)))
1539 if (! (*info->callbacks->notice) (info, h->root.string, abfd, section,
1540 value))
1541 return false;
1544 if (hashp != (struct bfd_link_hash_entry **) NULL)
1545 *hashp = h;
1549 enum link_action action;
1551 cycle = false;
1552 action = link_action[(int) row][(int) h->type];
1553 switch (action)
1555 case FAIL:
1556 abort ();
1558 case NOACT:
1559 /* Do nothing. */
1560 break;
1562 case UND:
1563 /* Make a new undefined symbol. */
1564 h->type = bfd_link_hash_undefined;
1565 h->u.undef.abfd = abfd;
1566 bfd_link_add_undef (info->hash, h);
1567 break;
1569 case WEAK:
1570 /* Make a new weak undefined symbol. */
1571 h->type = bfd_link_hash_undefweak;
1572 h->u.undef.abfd = abfd;
1573 break;
1575 case CDEF:
1576 /* We have found a definition for a symbol which was
1577 previously common. */
1578 BFD_ASSERT (h->type == bfd_link_hash_common);
1579 if (! ((*info->callbacks->multiple_common)
1580 (info, h->root.string,
1581 h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size,
1582 abfd, bfd_link_hash_defined, (bfd_vma) 0)))
1583 return false;
1584 /* Fall through. */
1585 case DEF:
1586 case DEFW:
1588 enum bfd_link_hash_type oldtype;
1590 /* Define a symbol. */
1591 oldtype = h->type;
1592 if (action == DEFW)
1593 h->type = bfd_link_hash_defweak;
1594 else
1595 h->type = bfd_link_hash_defined;
1596 h->u.def.section = section;
1597 h->u.def.value = value;
1599 /* If we have been asked to, we act like collect2 and
1600 identify all functions that might be global
1601 constructors and destructors and pass them up in a
1602 callback. We only do this for certain object file
1603 types, since many object file types can handle this
1604 automatically. */
1605 if (collect && name[0] == '_')
1607 const char *s;
1609 /* A constructor or destructor name starts like this:
1610 _+GLOBAL_[_.$][ID][_.$] where the first [_.$] and
1611 the second are the same character (we accept any
1612 character there, in case a new object file format
1613 comes along with even worse naming restrictions). */
1615 #define CONS_PREFIX "GLOBAL_"
1616 #define CONS_PREFIX_LEN (sizeof CONS_PREFIX - 1)
1618 s = name + 1;
1619 while (*s == '_')
1620 ++s;
1621 if (s[0] == 'G'
1622 && strncmp (s, CONS_PREFIX, CONS_PREFIX_LEN - 1) == 0)
1624 char c;
1626 c = s[CONS_PREFIX_LEN + 1];
1627 if ((c == 'I' || c == 'D')
1628 && s[CONS_PREFIX_LEN] == s[CONS_PREFIX_LEN + 2])
1630 /* If this is a definition of a symbol which
1631 was previously weakly defined, we are in
1632 trouble. We have already added a
1633 constructor entry for the weak defined
1634 symbol, and now we are trying to add one
1635 for the new symbol. Fortunately, this case
1636 should never arise in practice. */
1637 if (oldtype == bfd_link_hash_defweak)
1638 abort ();
1640 if (! ((*info->callbacks->constructor)
1641 (info,
1642 c == 'I' ? true : false,
1643 h->root.string, abfd, section, value)))
1644 return false;
1650 break;
1652 case COM:
1653 /* We have found a common definition for a symbol. */
1654 if (h->type == bfd_link_hash_new)
1655 bfd_link_add_undef (info->hash, h);
1656 h->type = bfd_link_hash_common;
1657 h->u.c.p =
1658 ((struct bfd_link_hash_common_entry *)
1659 bfd_hash_allocate (&info->hash->table,
1660 sizeof (struct bfd_link_hash_common_entry)));
1661 if (h->u.c.p == NULL)
1662 return false;
1664 h->u.c.size = value;
1666 /* Select a default alignment based on the size. This may
1667 be overridden by the caller. */
1669 unsigned int power;
1671 power = bfd_log2 (value);
1672 if (power > 4)
1673 power = 4;
1674 h->u.c.p->alignment_power = power;
1677 /* The section of a common symbol is only used if the common
1678 symbol is actually allocated. It basically provides a
1679 hook for the linker script to decide which output section
1680 the common symbols should be put in. In most cases, the
1681 section of a common symbol will be bfd_com_section_ptr,
1682 the code here will choose a common symbol section named
1683 "COMMON", and the linker script will contain *(COMMON) in
1684 the appropriate place. A few targets use separate common
1685 sections for small symbols, and they require special
1686 handling. */
1687 if (section == bfd_com_section_ptr)
1689 h->u.c.p->section = bfd_make_section_old_way (abfd, "COMMON");
1690 h->u.c.p->section->flags = SEC_ALLOC;
1692 else if (section->owner != abfd)
1694 h->u.c.p->section = bfd_make_section_old_way (abfd,
1695 section->name);
1696 h->u.c.p->section->flags = SEC_ALLOC;
1698 else
1699 h->u.c.p->section = section;
1700 break;
1702 case REF:
1703 /* A reference to a defined symbol. */
1704 if (h->next == NULL && info->hash->undefs_tail != h)
1705 h->next = h;
1706 break;
1708 case BIG:
1709 /* We have found a common definition for a symbol which
1710 already had a common definition. Use the maximum of the
1711 two sizes, and use the section required by the larger symbol. */
1712 BFD_ASSERT (h->type == bfd_link_hash_common);
1713 if (! ((*info->callbacks->multiple_common)
1714 (info, h->root.string,
1715 h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size,
1716 abfd, bfd_link_hash_common, value)))
1717 return false;
1718 if (value > h->u.c.size)
1720 unsigned int power;
1722 h->u.c.size = value;
1724 /* Select a default alignment based on the size. This may
1725 be overridden by the caller. */
1726 power = bfd_log2 (value);
1727 if (power > 4)
1728 power = 4;
1729 h->u.c.p->alignment_power = power;
1731 /* Some systems have special treatment for small commons,
1732 hence we want to select the section used by the larger
1733 symbol. This makes sure the symbol does not go in a
1734 small common section if it is now too large. */
1735 if (section == bfd_com_section_ptr)
1737 h->u.c.p->section
1738 = bfd_make_section_old_way (abfd, "COMMON");
1739 h->u.c.p->section->flags = SEC_ALLOC;
1741 else if (section->owner != abfd)
1743 h->u.c.p->section
1744 = bfd_make_section_old_way (abfd, section->name);
1745 h->u.c.p->section->flags = SEC_ALLOC;
1747 else
1748 h->u.c.p->section = section;
1750 break;
1752 case CREF:
1754 bfd *obfd;
1756 /* We have found a common definition for a symbol which
1757 was already defined. FIXME: It would nice if we could
1758 report the BFD which defined an indirect symbol, but we
1759 don't have anywhere to store the information. */
1760 if (h->type == bfd_link_hash_defined
1761 || h->type == bfd_link_hash_defweak)
1762 obfd = h->u.def.section->owner;
1763 else
1764 obfd = NULL;
1765 if (! ((*info->callbacks->multiple_common)
1766 (info, h->root.string, obfd, h->type, (bfd_vma) 0,
1767 abfd, bfd_link_hash_common, value)))
1768 return false;
1770 break;
1772 case MIND:
1773 /* Multiple indirect symbols. This is OK if they both point
1774 to the same symbol. */
1775 if (strcmp (h->u.i.link->root.string, string) == 0)
1776 break;
1777 /* Fall through. */
1778 case MDEF:
1779 /* Handle a multiple definition. */
1781 asection *msec = NULL;
1782 bfd_vma mval = 0;
1784 switch (h->type)
1786 case bfd_link_hash_defined:
1787 msec = h->u.def.section;
1788 mval = h->u.def.value;
1789 break;
1790 case bfd_link_hash_indirect:
1791 msec = bfd_ind_section_ptr;
1792 mval = 0;
1793 break;
1794 default:
1795 abort ();
1798 /* Ignore a redefinition of an absolute symbol to the same
1799 value; it's harmless. */
1800 if (h->type == bfd_link_hash_defined
1801 && bfd_is_abs_section (msec)
1802 && bfd_is_abs_section (section)
1803 && value == mval)
1804 break;
1806 if (! ((*info->callbacks->multiple_definition)
1807 (info, h->root.string, msec->owner, msec, mval, abfd,
1808 section, value)))
1809 return false;
1811 break;
1813 case CIND:
1814 /* Create an indirect symbol from an existing common symbol. */
1815 BFD_ASSERT (h->type == bfd_link_hash_common);
1816 if (! ((*info->callbacks->multiple_common)
1817 (info, h->root.string,
1818 h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size,
1819 abfd, bfd_link_hash_indirect, (bfd_vma) 0)))
1820 return false;
1821 /* Fall through. */
1822 case IND:
1823 /* Create an indirect symbol. */
1825 struct bfd_link_hash_entry *inh;
1827 /* STRING is the name of the symbol we want to indirect
1828 to. */
1829 inh = bfd_wrapped_link_hash_lookup (abfd, info, string, true,
1830 copy, false);
1831 if (inh == (struct bfd_link_hash_entry *) NULL)
1832 return false;
1833 if (inh->type == bfd_link_hash_indirect
1834 && inh->u.i.link == h)
1836 (*_bfd_error_handler)
1837 (_("%s: indirect symbol `%s' to `%s' is a loop"),
1838 bfd_get_filename (abfd), name, string);
1839 bfd_set_error (bfd_error_invalid_operation);
1840 return false;
1842 if (inh->type == bfd_link_hash_new)
1844 inh->type = bfd_link_hash_undefined;
1845 inh->u.undef.abfd = abfd;
1846 bfd_link_add_undef (info->hash, inh);
1849 /* If the indirect symbol has been referenced, we need to
1850 push the reference down to the symbol we are
1851 referencing. */
1852 if (h->type != bfd_link_hash_new)
1854 row = UNDEF_ROW;
1855 cycle = true;
1858 h->type = bfd_link_hash_indirect;
1859 h->u.i.link = inh;
1861 break;
1863 case SET:
1864 /* Add an entry to a set. */
1865 if (! (*info->callbacks->add_to_set) (info, h, BFD_RELOC_CTOR,
1866 abfd, section, value))
1867 return false;
1868 break;
1870 case WARNC:
1871 /* Issue a warning and cycle. */
1872 if (h->u.i.warning != NULL)
1874 if (! (*info->callbacks->warning) (info, h->u.i.warning,
1875 h->root.string, abfd,
1876 (asection *) NULL,
1877 (bfd_vma) 0))
1878 return false;
1879 /* Only issue a warning once. */
1880 h->u.i.warning = NULL;
1882 /* Fall through. */
1883 case CYCLE:
1884 /* Try again with the referenced symbol. */
1885 h = h->u.i.link;
1886 cycle = true;
1887 break;
1889 case REFC:
1890 /* A reference to an indirect symbol. */
1891 if (h->next == NULL && info->hash->undefs_tail != h)
1892 h->next = h;
1893 h = h->u.i.link;
1894 cycle = true;
1895 break;
1897 case WARN:
1898 /* Issue a warning. */
1899 if (! (*info->callbacks->warning) (info, string, h->root.string,
1900 hash_entry_bfd (h),
1901 (asection *) NULL, (bfd_vma) 0))
1902 return false;
1903 break;
1905 case CWARN:
1906 /* Warn if this symbol has been referenced already,
1907 otherwise add a warning. A symbol has been referenced if
1908 the next field is not NULL, or it is the tail of the
1909 undefined symbol list. The REF case above helps to
1910 ensure this. */
1911 if (h->next != NULL || info->hash->undefs_tail == h)
1913 if (! (*info->callbacks->warning) (info, string, h->root.string,
1914 hash_entry_bfd (h),
1915 (asection *) NULL,
1916 (bfd_vma) 0))
1917 return false;
1918 break;
1920 /* Fall through. */
1921 case MWARN:
1922 /* Make a warning symbol. */
1924 struct bfd_link_hash_entry *sub;
1926 /* STRING is the warning to give. */
1927 sub = ((struct bfd_link_hash_entry *)
1928 ((*info->hash->table.newfunc)
1929 ((struct bfd_hash_entry *) NULL, &info->hash->table,
1930 h->root.string)));
1931 if (sub == NULL)
1932 return false;
1933 *sub = *h;
1934 sub->type = bfd_link_hash_warning;
1935 sub->u.i.link = h;
1936 if (! copy)
1937 sub->u.i.warning = string;
1938 else
1940 char *w;
1942 w = bfd_hash_allocate (&info->hash->table,
1943 strlen (string) + 1);
1944 if (w == NULL)
1945 return false;
1946 strcpy (w, string);
1947 sub->u.i.warning = w;
1950 bfd_hash_replace (&info->hash->table,
1951 (struct bfd_hash_entry *) h,
1952 (struct bfd_hash_entry *) sub);
1953 if (hashp != NULL)
1954 *hashp = sub;
1956 break;
1959 while (cycle);
1961 return true;
1964 /* Generic final link routine. */
1966 boolean
1967 _bfd_generic_final_link (abfd, info)
1968 bfd *abfd;
1969 struct bfd_link_info *info;
1971 bfd *sub;
1972 asection *o;
1973 struct bfd_link_order *p;
1974 size_t outsymalloc;
1975 struct generic_write_global_symbol_info wginfo;
1977 bfd_get_outsymbols (abfd) = (asymbol **) NULL;
1978 bfd_get_symcount (abfd) = 0;
1979 outsymalloc = 0;
1981 /* Mark all sections which will be included in the output file. */
1982 for (o = abfd->sections; o != NULL; o = o->next)
1983 for (p = o->link_order_head; p != NULL; p = p->next)
1984 if (p->type == bfd_indirect_link_order)
1985 p->u.indirect.section->linker_mark = true;
1987 /* Build the output symbol table. */
1988 for (sub = info->input_bfds; sub != (bfd *) NULL; sub = sub->link_next)
1989 if (! _bfd_generic_link_output_symbols (abfd, sub, info, &outsymalloc))
1990 return false;
1992 /* Accumulate the global symbols. */
1993 wginfo.info = info;
1994 wginfo.output_bfd = abfd;
1995 wginfo.psymalloc = &outsymalloc;
1996 _bfd_generic_link_hash_traverse (_bfd_generic_hash_table (info),
1997 _bfd_generic_link_write_global_symbol,
1998 (PTR) &wginfo);
2000 /* Make sure we have a trailing NULL pointer on OUTSYMBOLS. We
2001 shouldn't really need one, since we have SYMCOUNT, but some old
2002 code still expects one. */
2003 if (! generic_add_output_symbol (abfd, &outsymalloc, NULL))
2004 return false;
2006 if (info->relocateable)
2008 /* Allocate space for the output relocs for each section. */
2009 for (o = abfd->sections;
2010 o != (asection *) NULL;
2011 o = o->next)
2013 o->reloc_count = 0;
2014 for (p = o->link_order_head;
2015 p != (struct bfd_link_order *) NULL;
2016 p = p->next)
2018 if (p->type == bfd_section_reloc_link_order
2019 || p->type == bfd_symbol_reloc_link_order)
2020 ++o->reloc_count;
2021 else if (p->type == bfd_indirect_link_order)
2023 asection *input_section;
2024 bfd *input_bfd;
2025 long relsize;
2026 arelent **relocs;
2027 asymbol **symbols;
2028 long reloc_count;
2030 input_section = p->u.indirect.section;
2031 input_bfd = input_section->owner;
2032 relsize = bfd_get_reloc_upper_bound (input_bfd,
2033 input_section);
2034 if (relsize < 0)
2035 return false;
2036 relocs = (arelent **) bfd_malloc ((size_t) relsize);
2037 if (!relocs && relsize != 0)
2038 return false;
2039 symbols = _bfd_generic_link_get_symbols (input_bfd);
2040 reloc_count = bfd_canonicalize_reloc (input_bfd,
2041 input_section,
2042 relocs,
2043 symbols);
2044 if (reloc_count < 0)
2045 return false;
2046 BFD_ASSERT ((unsigned long) reloc_count
2047 == input_section->reloc_count);
2048 o->reloc_count += reloc_count;
2049 free (relocs);
2052 if (o->reloc_count > 0)
2054 o->orelocation = ((arelent **)
2055 bfd_alloc (abfd,
2056 (o->reloc_count
2057 * sizeof (arelent *))));
2058 if (!o->orelocation)
2059 return false;
2060 o->flags |= SEC_RELOC;
2061 /* Reset the count so that it can be used as an index
2062 when putting in the output relocs. */
2063 o->reloc_count = 0;
2068 /* Handle all the link order information for the sections. */
2069 for (o = abfd->sections;
2070 o != (asection *) NULL;
2071 o = o->next)
2073 for (p = o->link_order_head;
2074 p != (struct bfd_link_order *) NULL;
2075 p = p->next)
2077 switch (p->type)
2079 case bfd_section_reloc_link_order:
2080 case bfd_symbol_reloc_link_order:
2081 if (! _bfd_generic_reloc_link_order (abfd, info, o, p))
2082 return false;
2083 break;
2084 case bfd_indirect_link_order:
2085 if (! default_indirect_link_order (abfd, info, o, p, true))
2086 return false;
2087 break;
2088 default:
2089 if (! _bfd_default_link_order (abfd, info, o, p))
2090 return false;
2091 break;
2096 return true;
2099 /* Add an output symbol to the output BFD. */
2101 static boolean
2102 generic_add_output_symbol (output_bfd, psymalloc, sym)
2103 bfd *output_bfd;
2104 size_t *psymalloc;
2105 asymbol *sym;
2107 if (bfd_get_symcount (output_bfd) >= *psymalloc)
2109 asymbol **newsyms;
2111 if (*psymalloc == 0)
2112 *psymalloc = 124;
2113 else
2114 *psymalloc *= 2;
2115 newsyms = (asymbol **) bfd_realloc (bfd_get_outsymbols (output_bfd),
2116 *psymalloc * sizeof (asymbol *));
2117 if (newsyms == (asymbol **) NULL)
2118 return false;
2119 bfd_get_outsymbols (output_bfd) = newsyms;
2122 bfd_get_outsymbols (output_bfd) [bfd_get_symcount (output_bfd)] = sym;
2123 if (sym != NULL)
2124 ++ bfd_get_symcount (output_bfd);
2126 return true;
2129 /* Handle the symbols for an input BFD. */
2131 boolean
2132 _bfd_generic_link_output_symbols (output_bfd, input_bfd, info, psymalloc)
2133 bfd *output_bfd;
2134 bfd *input_bfd;
2135 struct bfd_link_info *info;
2136 size_t *psymalloc;
2138 asymbol **sym_ptr;
2139 asymbol **sym_end;
2141 if (! generic_link_read_symbols (input_bfd))
2142 return false;
2144 /* Create a filename symbol if we are supposed to. */
2145 if (info->create_object_symbols_section != (asection *) NULL)
2147 asection *sec;
2149 for (sec = input_bfd->sections;
2150 sec != (asection *) NULL;
2151 sec = sec->next)
2153 if (sec->output_section == info->create_object_symbols_section)
2155 asymbol *newsym;
2157 newsym = bfd_make_empty_symbol (input_bfd);
2158 if (!newsym)
2159 return false;
2160 newsym->name = input_bfd->filename;
2161 newsym->value = 0;
2162 newsym->flags = BSF_LOCAL | BSF_FILE;
2163 newsym->section = sec;
2165 if (! generic_add_output_symbol (output_bfd, psymalloc,
2166 newsym))
2167 return false;
2169 break;
2174 /* Adjust the values of the globally visible symbols, and write out
2175 local symbols. */
2176 sym_ptr = _bfd_generic_link_get_symbols (input_bfd);
2177 sym_end = sym_ptr + _bfd_generic_link_get_symcount (input_bfd);
2178 for (; sym_ptr < sym_end; sym_ptr++)
2180 asymbol *sym;
2181 struct generic_link_hash_entry *h;
2182 boolean output;
2184 h = (struct generic_link_hash_entry *) NULL;
2185 sym = *sym_ptr;
2186 if ((sym->flags & (BSF_INDIRECT
2187 | BSF_WARNING
2188 | BSF_GLOBAL
2189 | BSF_CONSTRUCTOR
2190 | BSF_WEAK)) != 0
2191 || bfd_is_und_section (bfd_get_section (sym))
2192 || bfd_is_com_section (bfd_get_section (sym))
2193 || bfd_is_ind_section (bfd_get_section (sym)))
2195 if (sym->udata.p != NULL)
2196 h = (struct generic_link_hash_entry *) sym->udata.p;
2197 else if ((sym->flags & BSF_CONSTRUCTOR) != 0)
2199 /* This case normally means that the main linker code
2200 deliberately ignored this constructor symbol. We
2201 should just pass it through. This will screw up if
2202 the constructor symbol is from a different,
2203 non-generic, object file format, but the case will
2204 only arise when linking with -r, which will probably
2205 fail anyhow, since there will be no way to represent
2206 the relocs in the output format being used. */
2207 h = NULL;
2209 else if (bfd_is_und_section (bfd_get_section (sym)))
2210 h = ((struct generic_link_hash_entry *)
2211 bfd_wrapped_link_hash_lookup (output_bfd, info,
2212 bfd_asymbol_name (sym),
2213 false, false, true));
2214 else
2215 h = _bfd_generic_link_hash_lookup (_bfd_generic_hash_table (info),
2216 bfd_asymbol_name (sym),
2217 false, false, true);
2219 if (h != (struct generic_link_hash_entry *) NULL)
2221 /* Force all references to this symbol to point to
2222 the same area in memory. It is possible that
2223 this routine will be called with a hash table
2224 other than a generic hash table, so we double
2225 check that. */
2226 if (info->hash->creator == input_bfd->xvec)
2228 if (h->sym != (asymbol *) NULL)
2229 *sym_ptr = sym = h->sym;
2232 switch (h->root.type)
2234 default:
2235 case bfd_link_hash_new:
2236 abort ();
2237 case bfd_link_hash_undefined:
2238 break;
2239 case bfd_link_hash_undefweak:
2240 sym->flags |= BSF_WEAK;
2241 break;
2242 case bfd_link_hash_indirect:
2243 h = (struct generic_link_hash_entry *) h->root.u.i.link;
2244 /* fall through */
2245 case bfd_link_hash_defined:
2246 sym->flags |= BSF_GLOBAL;
2247 sym->flags &=~ BSF_CONSTRUCTOR;
2248 sym->value = h->root.u.def.value;
2249 sym->section = h->root.u.def.section;
2250 break;
2251 case bfd_link_hash_defweak:
2252 sym->flags |= BSF_WEAK;
2253 sym->flags &=~ BSF_CONSTRUCTOR;
2254 sym->value = h->root.u.def.value;
2255 sym->section = h->root.u.def.section;
2256 break;
2257 case bfd_link_hash_common:
2258 sym->value = h->root.u.c.size;
2259 sym->flags |= BSF_GLOBAL;
2260 if (! bfd_is_com_section (sym->section))
2262 BFD_ASSERT (bfd_is_und_section (sym->section));
2263 sym->section = bfd_com_section_ptr;
2265 /* We do not set the section of the symbol to
2266 h->root.u.c.p->section. That value was saved so
2267 that we would know where to allocate the symbol
2268 if it was defined. In this case the type is
2269 still bfd_link_hash_common, so we did not define
2270 it, so we do not want to use that section. */
2271 break;
2276 /* This switch is straight from the old code in
2277 write_file_locals in ldsym.c. */
2278 if (info->strip == strip_all
2279 || (info->strip == strip_some
2280 && (bfd_hash_lookup (info->keep_hash, bfd_asymbol_name (sym),
2281 false, false)
2282 == (struct bfd_hash_entry *) NULL)))
2283 output = false;
2284 else if ((sym->flags & (BSF_GLOBAL | BSF_WEAK)) != 0)
2286 /* If this symbol is marked as occurring now, rather
2287 than at the end, output it now. This is used for
2288 COFF C_EXT FCN symbols. FIXME: There must be a
2289 better way. */
2290 if (bfd_asymbol_bfd (sym) == input_bfd
2291 && (sym->flags & BSF_NOT_AT_END) != 0)
2292 output = true;
2293 else
2294 output = false;
2296 else if (bfd_is_ind_section (sym->section))
2297 output = false;
2298 else if ((sym->flags & BSF_DEBUGGING) != 0)
2300 if (info->strip == strip_none)
2301 output = true;
2302 else
2303 output = false;
2305 else if (bfd_is_und_section (sym->section)
2306 || bfd_is_com_section (sym->section))
2307 output = false;
2308 else if ((sym->flags & BSF_LOCAL) != 0)
2310 if ((sym->flags & BSF_WARNING) != 0)
2311 output = false;
2312 else
2314 switch (info->discard)
2316 default:
2317 case discard_all:
2318 output = false;
2319 break;
2320 case discard_sec_merge:
2321 output = true;
2322 if (info->relocateable
2323 || ! (sym->section->flags & SEC_MERGE))
2324 break;
2325 /* FALLTHROUGH */
2326 case discard_l:
2327 if (bfd_is_local_label (input_bfd, sym))
2328 output = false;
2329 else
2330 output = true;
2331 break;
2332 case discard_none:
2333 output = true;
2334 break;
2338 else if ((sym->flags & BSF_CONSTRUCTOR))
2340 if (info->strip != strip_all)
2341 output = true;
2342 else
2343 output = false;
2345 else
2346 abort ();
2348 /* If this symbol is in a section which is not being included
2349 in the output file, then we don't want to output the symbol.
2351 Gross. .bss and similar sections won't have the linker_mark
2352 field set. */
2353 if ((sym->section->flags & SEC_HAS_CONTENTS) != 0
2354 && sym->section->linker_mark == false)
2355 output = false;
2357 if (output)
2359 if (! generic_add_output_symbol (output_bfd, psymalloc, sym))
2360 return false;
2361 if (h != (struct generic_link_hash_entry *) NULL)
2362 h->written = true;
2366 return true;
2369 /* Set the section and value of a generic BFD symbol based on a linker
2370 hash table entry. */
2372 static void
2373 set_symbol_from_hash (sym, h)
2374 asymbol *sym;
2375 struct bfd_link_hash_entry *h;
2377 switch (h->type)
2379 default:
2380 abort ();
2381 break;
2382 case bfd_link_hash_new:
2383 /* This can happen when a constructor symbol is seen but we are
2384 not building constructors. */
2385 if (sym->section != NULL)
2387 BFD_ASSERT ((sym->flags & BSF_CONSTRUCTOR) != 0);
2389 else
2391 sym->flags |= BSF_CONSTRUCTOR;
2392 sym->section = bfd_abs_section_ptr;
2393 sym->value = 0;
2395 break;
2396 case bfd_link_hash_undefined:
2397 sym->section = bfd_und_section_ptr;
2398 sym->value = 0;
2399 break;
2400 case bfd_link_hash_undefweak:
2401 sym->section = bfd_und_section_ptr;
2402 sym->value = 0;
2403 sym->flags |= BSF_WEAK;
2404 break;
2405 case bfd_link_hash_defined:
2406 sym->section = h->u.def.section;
2407 sym->value = h->u.def.value;
2408 break;
2409 case bfd_link_hash_defweak:
2410 sym->flags |= BSF_WEAK;
2411 sym->section = h->u.def.section;
2412 sym->value = h->u.def.value;
2413 break;
2414 case bfd_link_hash_common:
2415 sym->value = h->u.c.size;
2416 if (sym->section == NULL)
2417 sym->section = bfd_com_section_ptr;
2418 else if (! bfd_is_com_section (sym->section))
2420 BFD_ASSERT (bfd_is_und_section (sym->section));
2421 sym->section = bfd_com_section_ptr;
2423 /* Do not set the section; see _bfd_generic_link_output_symbols. */
2424 break;
2425 case bfd_link_hash_indirect:
2426 case bfd_link_hash_warning:
2427 /* FIXME: What should we do here? */
2428 break;
2432 /* Write out a global symbol, if it hasn't already been written out.
2433 This is called for each symbol in the hash table. */
2435 boolean
2436 _bfd_generic_link_write_global_symbol (h, data)
2437 struct generic_link_hash_entry *h;
2438 PTR data;
2440 struct generic_write_global_symbol_info *wginfo =
2441 (struct generic_write_global_symbol_info *) data;
2442 asymbol *sym;
2444 if (h->written)
2445 return true;
2447 h->written = true;
2449 if (wginfo->info->strip == strip_all
2450 || (wginfo->info->strip == strip_some
2451 && bfd_hash_lookup (wginfo->info->keep_hash, h->root.root.string,
2452 false, false) == NULL))
2453 return true;
2455 if (h->sym != (asymbol *) NULL)
2456 sym = h->sym;
2457 else
2459 sym = bfd_make_empty_symbol (wginfo->output_bfd);
2460 if (!sym)
2461 return false;
2462 sym->name = h->root.root.string;
2463 sym->flags = 0;
2466 set_symbol_from_hash (sym, &h->root);
2468 sym->flags |= BSF_GLOBAL;
2470 if (! generic_add_output_symbol (wginfo->output_bfd, wginfo->psymalloc,
2471 sym))
2473 /* FIXME: No way to return failure. */
2474 abort ();
2477 return true;
2480 /* Create a relocation. */
2482 boolean
2483 _bfd_generic_reloc_link_order (abfd, info, sec, link_order)
2484 bfd *abfd;
2485 struct bfd_link_info *info;
2486 asection *sec;
2487 struct bfd_link_order *link_order;
2489 arelent *r;
2491 if (! info->relocateable)
2492 abort ();
2493 if (sec->orelocation == (arelent **) NULL)
2494 abort ();
2496 r = (arelent *) bfd_alloc (abfd, sizeof (arelent));
2497 if (r == (arelent *) NULL)
2498 return false;
2500 r->address = link_order->offset;
2501 r->howto = bfd_reloc_type_lookup (abfd, link_order->u.reloc.p->reloc);
2502 if (r->howto == 0)
2504 bfd_set_error (bfd_error_bad_value);
2505 return false;
2508 /* Get the symbol to use for the relocation. */
2509 if (link_order->type == bfd_section_reloc_link_order)
2510 r->sym_ptr_ptr = link_order->u.reloc.p->u.section->symbol_ptr_ptr;
2511 else
2513 struct generic_link_hash_entry *h;
2515 h = ((struct generic_link_hash_entry *)
2516 bfd_wrapped_link_hash_lookup (abfd, info,
2517 link_order->u.reloc.p->u.name,
2518 false, false, true));
2519 if (h == (struct generic_link_hash_entry *) NULL
2520 || ! h->written)
2522 if (! ((*info->callbacks->unattached_reloc)
2523 (info, link_order->u.reloc.p->u.name,
2524 (bfd *) NULL, (asection *) NULL, (bfd_vma) 0)))
2525 return false;
2526 bfd_set_error (bfd_error_bad_value);
2527 return false;
2529 r->sym_ptr_ptr = &h->sym;
2532 /* If this is an inplace reloc, write the addend to the object file.
2533 Otherwise, store it in the reloc addend. */
2534 if (! r->howto->partial_inplace)
2535 r->addend = link_order->u.reloc.p->addend;
2536 else
2538 bfd_size_type size;
2539 bfd_reloc_status_type rstat;
2540 bfd_byte *buf;
2541 boolean ok;
2543 size = bfd_get_reloc_size (r->howto);
2544 buf = (bfd_byte *) bfd_zmalloc (size);
2545 if (buf == (bfd_byte *) NULL)
2546 return false;
2547 rstat = _bfd_relocate_contents (r->howto, abfd,
2548 link_order->u.reloc.p->addend, buf);
2549 switch (rstat)
2551 case bfd_reloc_ok:
2552 break;
2553 default:
2554 case bfd_reloc_outofrange:
2555 abort ();
2556 case bfd_reloc_overflow:
2557 if (! ((*info->callbacks->reloc_overflow)
2558 (info,
2559 (link_order->type == bfd_section_reloc_link_order
2560 ? bfd_section_name (abfd, link_order->u.reloc.p->u.section)
2561 : link_order->u.reloc.p->u.name),
2562 r->howto->name, link_order->u.reloc.p->addend,
2563 (bfd *) NULL, (asection *) NULL, (bfd_vma) 0)))
2565 free (buf);
2566 return false;
2568 break;
2570 ok = bfd_set_section_contents (abfd, sec, (PTR) buf,
2571 (file_ptr)
2572 (link_order->offset *
2573 bfd_octets_per_byte (abfd)), size);
2574 free (buf);
2575 if (! ok)
2576 return false;
2578 r->addend = 0;
2581 sec->orelocation[sec->reloc_count] = r;
2582 ++sec->reloc_count;
2584 return true;
2587 /* Allocate a new link_order for a section. */
2589 struct bfd_link_order *
2590 bfd_new_link_order (abfd, section)
2591 bfd *abfd;
2592 asection *section;
2594 struct bfd_link_order *new;
2596 new = ((struct bfd_link_order *)
2597 bfd_alloc (abfd, sizeof (struct bfd_link_order)));
2598 if (!new)
2599 return NULL;
2601 new->type = bfd_undefined_link_order;
2602 new->offset = 0;
2603 new->size = 0;
2604 new->next = (struct bfd_link_order *) NULL;
2606 if (section->link_order_tail != (struct bfd_link_order *) NULL)
2607 section->link_order_tail->next = new;
2608 else
2609 section->link_order_head = new;
2610 section->link_order_tail = new;
2612 return new;
2615 /* Default link order processing routine. Note that we can not handle
2616 the reloc_link_order types here, since they depend upon the details
2617 of how the particular backends generates relocs. */
2619 boolean
2620 _bfd_default_link_order (abfd, info, sec, link_order)
2621 bfd *abfd;
2622 struct bfd_link_info *info;
2623 asection *sec;
2624 struct bfd_link_order *link_order;
2626 switch (link_order->type)
2628 case bfd_undefined_link_order:
2629 case bfd_section_reloc_link_order:
2630 case bfd_symbol_reloc_link_order:
2631 default:
2632 abort ();
2633 case bfd_indirect_link_order:
2634 return default_indirect_link_order (abfd, info, sec, link_order,
2635 false);
2636 case bfd_fill_link_order:
2637 return default_fill_link_order (abfd, info, sec, link_order);
2638 case bfd_data_link_order:
2639 return bfd_set_section_contents (abfd, sec,
2640 (PTR) link_order->u.data.contents,
2641 (file_ptr)
2642 (link_order->offset *
2643 bfd_octets_per_byte (abfd)),
2644 link_order->size);
2648 /* Default routine to handle a bfd_fill_link_order. */
2650 static boolean
2651 default_fill_link_order (abfd, info, sec, link_order)
2652 bfd *abfd;
2653 struct bfd_link_info *info ATTRIBUTE_UNUSED;
2654 asection *sec;
2655 struct bfd_link_order *link_order;
2657 size_t size;
2658 char *space;
2659 size_t i;
2660 int fill;
2661 boolean result;
2663 BFD_ASSERT ((sec->flags & SEC_HAS_CONTENTS) != 0);
2665 size = (size_t) link_order->size;
2666 space = (char *) bfd_malloc (size);
2667 if (space == NULL && size != 0)
2668 return false;
2670 fill = link_order->u.fill.value;
2671 for (i = 0; i < size; i += 2)
2672 space[i] = fill >> 8;
2673 for (i = 1; i < size; i += 2)
2674 space[i] = fill;
2675 result = bfd_set_section_contents (abfd, sec, space,
2676 (file_ptr)
2677 (link_order->offset *
2678 bfd_octets_per_byte (abfd)),
2679 link_order->size);
2680 free (space);
2681 return result;
2684 /* Default routine to handle a bfd_indirect_link_order. */
2686 static boolean
2687 default_indirect_link_order (output_bfd, info, output_section, link_order,
2688 generic_linker)
2689 bfd *output_bfd;
2690 struct bfd_link_info *info;
2691 asection *output_section;
2692 struct bfd_link_order *link_order;
2693 boolean generic_linker;
2695 asection *input_section;
2696 bfd *input_bfd;
2697 bfd_byte *contents = NULL;
2698 bfd_byte *new_contents;
2700 BFD_ASSERT ((output_section->flags & SEC_HAS_CONTENTS) != 0);
2702 if (link_order->size == 0)
2703 return true;
2705 input_section = link_order->u.indirect.section;
2706 input_bfd = input_section->owner;
2708 BFD_ASSERT (input_section->output_section == output_section);
2709 BFD_ASSERT (input_section->output_offset == link_order->offset);
2710 BFD_ASSERT (input_section->_cooked_size == link_order->size);
2712 if (info->relocateable
2713 && input_section->reloc_count > 0
2714 && output_section->orelocation == (arelent **) NULL)
2716 /* Space has not been allocated for the output relocations.
2717 This can happen when we are called by a specific backend
2718 because somebody is attempting to link together different
2719 types of object files. Handling this case correctly is
2720 difficult, and sometimes impossible. */
2721 (*_bfd_error_handler)
2722 (_("Attempt to do relocateable link with %s input and %s output"),
2723 bfd_get_target (input_bfd), bfd_get_target (output_bfd));
2724 bfd_set_error (bfd_error_wrong_format);
2725 return false;
2728 if (! generic_linker)
2730 asymbol **sympp;
2731 asymbol **symppend;
2733 /* Get the canonical symbols. The generic linker will always
2734 have retrieved them by this point, but we are being called by
2735 a specific linker, presumably because we are linking
2736 different types of object files together. */
2737 if (! generic_link_read_symbols (input_bfd))
2738 return false;
2740 /* Since we have been called by a specific linker, rather than
2741 the generic linker, the values of the symbols will not be
2742 right. They will be the values as seen in the input file,
2743 not the values of the final link. We need to fix them up
2744 before we can relocate the section. */
2745 sympp = _bfd_generic_link_get_symbols (input_bfd);
2746 symppend = sympp + _bfd_generic_link_get_symcount (input_bfd);
2747 for (; sympp < symppend; sympp++)
2749 asymbol *sym;
2750 struct bfd_link_hash_entry *h;
2752 sym = *sympp;
2754 if ((sym->flags & (BSF_INDIRECT
2755 | BSF_WARNING
2756 | BSF_GLOBAL
2757 | BSF_CONSTRUCTOR
2758 | BSF_WEAK)) != 0
2759 || bfd_is_und_section (bfd_get_section (sym))
2760 || bfd_is_com_section (bfd_get_section (sym))
2761 || bfd_is_ind_section (bfd_get_section (sym)))
2763 /* sym->udata may have been set by
2764 generic_link_add_symbol_list. */
2765 if (sym->udata.p != NULL)
2766 h = (struct bfd_link_hash_entry *) sym->udata.p;
2767 else if (bfd_is_und_section (bfd_get_section (sym)))
2768 h = bfd_wrapped_link_hash_lookup (output_bfd, info,
2769 bfd_asymbol_name (sym),
2770 false, false, true);
2771 else
2772 h = bfd_link_hash_lookup (info->hash,
2773 bfd_asymbol_name (sym),
2774 false, false, true);
2775 if (h != NULL)
2776 set_symbol_from_hash (sym, h);
2781 /* Get and relocate the section contents. */
2782 contents = ((bfd_byte *)
2783 bfd_malloc (bfd_section_size (input_bfd, input_section)));
2784 if (contents == NULL && bfd_section_size (input_bfd, input_section) != 0)
2785 goto error_return;
2786 new_contents = (bfd_get_relocated_section_contents
2787 (output_bfd, info, link_order, contents, info->relocateable,
2788 _bfd_generic_link_get_symbols (input_bfd)));
2789 if (!new_contents)
2790 goto error_return;
2792 /* Output the section contents. */
2793 if (! bfd_set_section_contents (output_bfd, output_section,
2794 (PTR) new_contents,
2795 (file_ptr)
2796 (link_order->offset *
2797 bfd_octets_per_byte (output_bfd)),
2798 link_order->size))
2799 goto error_return;
2801 if (contents != NULL)
2802 free (contents);
2803 return true;
2805 error_return:
2806 if (contents != NULL)
2807 free (contents);
2808 return false;
2811 /* A little routine to count the number of relocs in a link_order
2812 list. */
2814 unsigned int
2815 _bfd_count_link_order_relocs (link_order)
2816 struct bfd_link_order *link_order;
2818 register unsigned int c;
2819 register struct bfd_link_order *l;
2821 c = 0;
2822 for (l = link_order; l != (struct bfd_link_order *) NULL; l = l->next)
2824 if (l->type == bfd_section_reloc_link_order
2825 || l->type == bfd_symbol_reloc_link_order)
2826 ++c;
2829 return c;
2833 FUNCTION
2834 bfd_link_split_section
2836 SYNOPSIS
2837 boolean bfd_link_split_section(bfd *abfd, asection *sec);
2839 DESCRIPTION
2840 Return nonzero if @var{sec} should be split during a
2841 reloceatable or final link.
2843 .#define bfd_link_split_section(abfd, sec) \
2844 . BFD_SEND (abfd, _bfd_link_split_section, (abfd, sec))
2849 boolean
2850 _bfd_generic_link_split_section (abfd, sec)
2851 bfd *abfd ATTRIBUTE_UNUSED;
2852 asection *sec ATTRIBUTE_UNUSED;
2854 return false;