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[binutils.git] / bfd / linker.c
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1 /* linker.c -- BFD linker routines
2 Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
3 2003, 2004, 2005, 2006, 2007
4 Free Software Foundation, Inc.
5 Written by Steve Chamberlain and Ian Lance Taylor, Cygnus Support
7 This file is part of BFD, the Binary File Descriptor library.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program; if not, write to the Free Software
21 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
22 MA 02110-1301, USA. */
24 #include "sysdep.h"
25 #include "bfd.h"
26 #include "libbfd.h"
27 #include "bfdlink.h"
28 #include "genlink.h"
31 SECTION
32 Linker Functions
34 @cindex Linker
35 The linker uses three special entry points in the BFD target
36 vector. It is not necessary to write special routines for
37 these entry points when creating a new BFD back end, since
38 generic versions are provided. However, writing them can
39 speed up linking and make it use significantly less runtime
40 memory.
42 The first routine creates a hash table used by the other
43 routines. The second routine adds the symbols from an object
44 file to the hash table. The third routine takes all the
45 object files and links them together to create the output
46 file. These routines are designed so that the linker proper
47 does not need to know anything about the symbols in the object
48 files that it is linking. The linker merely arranges the
49 sections as directed by the linker script and lets BFD handle
50 the details of symbols and relocs.
52 The second routine and third routines are passed a pointer to
53 a <<struct bfd_link_info>> structure (defined in
54 <<bfdlink.h>>) which holds information relevant to the link,
55 including the linker hash table (which was created by the
56 first routine) and a set of callback functions to the linker
57 proper.
59 The generic linker routines are in <<linker.c>>, and use the
60 header file <<genlink.h>>. As of this writing, the only back
61 ends which have implemented versions of these routines are
62 a.out (in <<aoutx.h>>) and ECOFF (in <<ecoff.c>>). The a.out
63 routines are used as examples throughout this section.
65 @menu
66 @* Creating a Linker Hash Table::
67 @* Adding Symbols to the Hash Table::
68 @* Performing the Final Link::
69 @end menu
71 INODE
72 Creating a Linker Hash Table, Adding Symbols to the Hash Table, Linker Functions, Linker Functions
73 SUBSECTION
74 Creating a linker hash table
76 @cindex _bfd_link_hash_table_create in target vector
77 @cindex target vector (_bfd_link_hash_table_create)
78 The linker routines must create a hash table, which must be
79 derived from <<struct bfd_link_hash_table>> described in
80 <<bfdlink.c>>. @xref{Hash Tables}, for information on how to
81 create a derived hash table. This entry point is called using
82 the target vector of the linker output file.
84 The <<_bfd_link_hash_table_create>> entry point must allocate
85 and initialize an instance of the desired hash table. If the
86 back end does not require any additional information to be
87 stored with the entries in the hash table, the entry point may
88 simply create a <<struct bfd_link_hash_table>>. Most likely,
89 however, some additional information will be needed.
91 For example, with each entry in the hash table the a.out
92 linker keeps the index the symbol has in the final output file
93 (this index number is used so that when doing a relocatable
94 link the symbol index used in the output file can be quickly
95 filled in when copying over a reloc). The a.out linker code
96 defines the required structures and functions for a hash table
97 derived from <<struct bfd_link_hash_table>>. The a.out linker
98 hash table is created by the function
99 <<NAME(aout,link_hash_table_create)>>; it simply allocates
100 space for the hash table, initializes it, and returns a
101 pointer to it.
103 When writing the linker routines for a new back end, you will
104 generally not know exactly which fields will be required until
105 you have finished. You should simply create a new hash table
106 which defines no additional fields, and then simply add fields
107 as they become necessary.
109 INODE
110 Adding Symbols to the Hash Table, Performing the Final Link, Creating a Linker Hash Table, Linker Functions
111 SUBSECTION
112 Adding symbols to the hash table
114 @cindex _bfd_link_add_symbols in target vector
115 @cindex target vector (_bfd_link_add_symbols)
116 The linker proper will call the <<_bfd_link_add_symbols>>
117 entry point for each object file or archive which is to be
118 linked (typically these are the files named on the command
119 line, but some may also come from the linker script). The
120 entry point is responsible for examining the file. For an
121 object file, BFD must add any relevant symbol information to
122 the hash table. For an archive, BFD must determine which
123 elements of the archive should be used and adding them to the
124 link.
126 The a.out version of this entry point is
127 <<NAME(aout,link_add_symbols)>>.
129 @menu
130 @* Differing file formats::
131 @* Adding symbols from an object file::
132 @* Adding symbols from an archive::
133 @end menu
135 INODE
136 Differing file formats, Adding symbols from an object file, Adding Symbols to the Hash Table, Adding Symbols to the Hash Table
137 SUBSUBSECTION
138 Differing file formats
140 Normally all the files involved in a link will be of the same
141 format, but it is also possible to link together different
142 format object files, and the back end must support that. The
143 <<_bfd_link_add_symbols>> entry point is called via the target
144 vector of the file to be added. This has an important
145 consequence: the function may not assume that the hash table
146 is the type created by the corresponding
147 <<_bfd_link_hash_table_create>> vector. All the
148 <<_bfd_link_add_symbols>> function can assume about the hash
149 table is that it is derived from <<struct
150 bfd_link_hash_table>>.
152 Sometimes the <<_bfd_link_add_symbols>> function must store
153 some information in the hash table entry to be used by the
154 <<_bfd_final_link>> function. In such a case the <<creator>>
155 field of the hash table must be checked to make sure that the
156 hash table was created by an object file of the same format.
158 The <<_bfd_final_link>> routine must be prepared to handle a
159 hash entry without any extra information added by the
160 <<_bfd_link_add_symbols>> function. A hash entry without
161 extra information will also occur when the linker script
162 directs the linker to create a symbol. Note that, regardless
163 of how a hash table entry is added, all the fields will be
164 initialized to some sort of null value by the hash table entry
165 initialization function.
167 See <<ecoff_link_add_externals>> for an example of how to
168 check the <<creator>> field before saving information (in this
169 case, the ECOFF external symbol debugging information) in a
170 hash table entry.
172 INODE
173 Adding symbols from an object file, Adding symbols from an archive, Differing file formats, Adding Symbols to the Hash Table
174 SUBSUBSECTION
175 Adding symbols from an object file
177 When the <<_bfd_link_add_symbols>> routine is passed an object
178 file, it must add all externally visible symbols in that
179 object file to the hash table. The actual work of adding the
180 symbol to the hash table is normally handled by the function
181 <<_bfd_generic_link_add_one_symbol>>. The
182 <<_bfd_link_add_symbols>> routine is responsible for reading
183 all the symbols from the object file and passing the correct
184 information to <<_bfd_generic_link_add_one_symbol>>.
186 The <<_bfd_link_add_symbols>> routine should not use
187 <<bfd_canonicalize_symtab>> to read the symbols. The point of
188 providing this routine is to avoid the overhead of converting
189 the symbols into generic <<asymbol>> structures.
191 @findex _bfd_generic_link_add_one_symbol
192 <<_bfd_generic_link_add_one_symbol>> handles the details of
193 combining common symbols, warning about multiple definitions,
194 and so forth. It takes arguments which describe the symbol to
195 add, notably symbol flags, a section, and an offset. The
196 symbol flags include such things as <<BSF_WEAK>> or
197 <<BSF_INDIRECT>>. The section is a section in the object
198 file, or something like <<bfd_und_section_ptr>> for an undefined
199 symbol or <<bfd_com_section_ptr>> for a common symbol.
201 If the <<_bfd_final_link>> routine is also going to need to
202 read the symbol information, the <<_bfd_link_add_symbols>>
203 routine should save it somewhere attached to the object file
204 BFD. However, the information should only be saved if the
205 <<keep_memory>> field of the <<info>> argument is TRUE, so
206 that the <<-no-keep-memory>> linker switch is effective.
208 The a.out function which adds symbols from an object file is
209 <<aout_link_add_object_symbols>>, and most of the interesting
210 work is in <<aout_link_add_symbols>>. The latter saves
211 pointers to the hash tables entries created by
212 <<_bfd_generic_link_add_one_symbol>> indexed by symbol number,
213 so that the <<_bfd_final_link>> routine does not have to call
214 the hash table lookup routine to locate the entry.
216 INODE
217 Adding symbols from an archive, , Adding symbols from an object file, Adding Symbols to the Hash Table
218 SUBSUBSECTION
219 Adding symbols from an archive
221 When the <<_bfd_link_add_symbols>> routine is passed an
222 archive, it must look through the symbols defined by the
223 archive and decide which elements of the archive should be
224 included in the link. For each such element it must call the
225 <<add_archive_element>> linker callback, and it must add the
226 symbols from the object file to the linker hash table.
228 @findex _bfd_generic_link_add_archive_symbols
229 In most cases the work of looking through the symbols in the
230 archive should be done by the
231 <<_bfd_generic_link_add_archive_symbols>> function. This
232 function builds a hash table from the archive symbol table and
233 looks through the list of undefined symbols to see which
234 elements should be included.
235 <<_bfd_generic_link_add_archive_symbols>> is passed a function
236 to call to make the final decision about adding an archive
237 element to the link and to do the actual work of adding the
238 symbols to the linker hash table.
240 The function passed to
241 <<_bfd_generic_link_add_archive_symbols>> must read the
242 symbols of the archive element and decide whether the archive
243 element should be included in the link. If the element is to
244 be included, the <<add_archive_element>> linker callback
245 routine must be called with the element as an argument, and
246 the elements symbols must be added to the linker hash table
247 just as though the element had itself been passed to the
248 <<_bfd_link_add_symbols>> function.
250 When the a.out <<_bfd_link_add_symbols>> function receives an
251 archive, it calls <<_bfd_generic_link_add_archive_symbols>>
252 passing <<aout_link_check_archive_element>> as the function
253 argument. <<aout_link_check_archive_element>> calls
254 <<aout_link_check_ar_symbols>>. If the latter decides to add
255 the element (an element is only added if it provides a real,
256 non-common, definition for a previously undefined or common
257 symbol) it calls the <<add_archive_element>> callback and then
258 <<aout_link_check_archive_element>> calls
259 <<aout_link_add_symbols>> to actually add the symbols to the
260 linker hash table.
262 The ECOFF back end is unusual in that it does not normally
263 call <<_bfd_generic_link_add_archive_symbols>>, because ECOFF
264 archives already contain a hash table of symbols. The ECOFF
265 back end searches the archive itself to avoid the overhead of
266 creating a new hash table.
268 INODE
269 Performing the Final Link, , Adding Symbols to the Hash Table, Linker Functions
270 SUBSECTION
271 Performing the final link
273 @cindex _bfd_link_final_link in target vector
274 @cindex target vector (_bfd_final_link)
275 When all the input files have been processed, the linker calls
276 the <<_bfd_final_link>> entry point of the output BFD. This
277 routine is responsible for producing the final output file,
278 which has several aspects. It must relocate the contents of
279 the input sections and copy the data into the output sections.
280 It must build an output symbol table including any local
281 symbols from the input files and the global symbols from the
282 hash table. When producing relocatable output, it must
283 modify the input relocs and write them into the output file.
284 There may also be object format dependent work to be done.
286 The linker will also call the <<write_object_contents>> entry
287 point when the BFD is closed. The two entry points must work
288 together in order to produce the correct output file.
290 The details of how this works are inevitably dependent upon
291 the specific object file format. The a.out
292 <<_bfd_final_link>> routine is <<NAME(aout,final_link)>>.
294 @menu
295 @* Information provided by the linker::
296 @* Relocating the section contents::
297 @* Writing the symbol table::
298 @end menu
300 INODE
301 Information provided by the linker, Relocating the section contents, Performing the Final Link, Performing the Final Link
302 SUBSUBSECTION
303 Information provided by the linker
305 Before the linker calls the <<_bfd_final_link>> entry point,
306 it sets up some data structures for the function to use.
308 The <<input_bfds>> field of the <<bfd_link_info>> structure
309 will point to a list of all the input files included in the
310 link. These files are linked through the <<link_next>> field
311 of the <<bfd>> structure.
313 Each section in the output file will have a list of
314 <<link_order>> structures attached to the <<map_head.link_order>>
315 field (the <<link_order>> structure is defined in
316 <<bfdlink.h>>). These structures describe how to create the
317 contents of the output section in terms of the contents of
318 various input sections, fill constants, and, eventually, other
319 types of information. They also describe relocs that must be
320 created by the BFD backend, but do not correspond to any input
321 file; this is used to support -Ur, which builds constructors
322 while generating a relocatable object file.
324 INODE
325 Relocating the section contents, Writing the symbol table, Information provided by the linker, Performing the Final Link
326 SUBSUBSECTION
327 Relocating the section contents
329 The <<_bfd_final_link>> function should look through the
330 <<link_order>> structures attached to each section of the
331 output file. Each <<link_order>> structure should either be
332 handled specially, or it should be passed to the function
333 <<_bfd_default_link_order>> which will do the right thing
334 (<<_bfd_default_link_order>> is defined in <<linker.c>>).
336 For efficiency, a <<link_order>> of type
337 <<bfd_indirect_link_order>> whose associated section belongs
338 to a BFD of the same format as the output BFD must be handled
339 specially. This type of <<link_order>> describes part of an
340 output section in terms of a section belonging to one of the
341 input files. The <<_bfd_final_link>> function should read the
342 contents of the section and any associated relocs, apply the
343 relocs to the section contents, and write out the modified
344 section contents. If performing a relocatable link, the
345 relocs themselves must also be modified and written out.
347 @findex _bfd_relocate_contents
348 @findex _bfd_final_link_relocate
349 The functions <<_bfd_relocate_contents>> and
350 <<_bfd_final_link_relocate>> provide some general support for
351 performing the actual relocations, notably overflow checking.
352 Their arguments include information about the symbol the
353 relocation is against and a <<reloc_howto_type>> argument
354 which describes the relocation to perform. These functions
355 are defined in <<reloc.c>>.
357 The a.out function which handles reading, relocating, and
358 writing section contents is <<aout_link_input_section>>. The
359 actual relocation is done in <<aout_link_input_section_std>>
360 and <<aout_link_input_section_ext>>.
362 INODE
363 Writing the symbol table, , Relocating the section contents, Performing the Final Link
364 SUBSUBSECTION
365 Writing the symbol table
367 The <<_bfd_final_link>> function must gather all the symbols
368 in the input files and write them out. It must also write out
369 all the symbols in the global hash table. This must be
370 controlled by the <<strip>> and <<discard>> fields of the
371 <<bfd_link_info>> structure.
373 The local symbols of the input files will not have been
374 entered into the linker hash table. The <<_bfd_final_link>>
375 routine must consider each input file and include the symbols
376 in the output file. It may be convenient to do this when
377 looking through the <<link_order>> structures, or it may be
378 done by stepping through the <<input_bfds>> list.
380 The <<_bfd_final_link>> routine must also traverse the global
381 hash table to gather all the externally visible symbols. It
382 is possible that most of the externally visible symbols may be
383 written out when considering the symbols of each input file,
384 but it is still necessary to traverse the hash table since the
385 linker script may have defined some symbols that are not in
386 any of the input files.
388 The <<strip>> field of the <<bfd_link_info>> structure
389 controls which symbols are written out. The possible values
390 are listed in <<bfdlink.h>>. If the value is <<strip_some>>,
391 then the <<keep_hash>> field of the <<bfd_link_info>>
392 structure is a hash table of symbols to keep; each symbol
393 should be looked up in this hash table, and only symbols which
394 are present should be included in the output file.
396 If the <<strip>> field of the <<bfd_link_info>> structure
397 permits local symbols to be written out, the <<discard>> field
398 is used to further controls which local symbols are included
399 in the output file. If the value is <<discard_l>>, then all
400 local symbols which begin with a certain prefix are discarded;
401 this is controlled by the <<bfd_is_local_label_name>> entry point.
403 The a.out backend handles symbols by calling
404 <<aout_link_write_symbols>> on each input BFD and then
405 traversing the global hash table with the function
406 <<aout_link_write_other_symbol>>. It builds a string table
407 while writing out the symbols, which is written to the output
408 file at the end of <<NAME(aout,final_link)>>.
411 static bfd_boolean generic_link_add_object_symbols
412 (bfd *, struct bfd_link_info *, bfd_boolean collect);
413 static bfd_boolean generic_link_add_symbols
414 (bfd *, struct bfd_link_info *, bfd_boolean);
415 static bfd_boolean generic_link_check_archive_element_no_collect
416 (bfd *, struct bfd_link_info *, bfd_boolean *);
417 static bfd_boolean generic_link_check_archive_element_collect
418 (bfd *, struct bfd_link_info *, bfd_boolean *);
419 static bfd_boolean generic_link_check_archive_element
420 (bfd *, struct bfd_link_info *, bfd_boolean *, bfd_boolean);
421 static bfd_boolean generic_link_add_symbol_list
422 (bfd *, struct bfd_link_info *, bfd_size_type count, asymbol **,
423 bfd_boolean);
424 static bfd_boolean generic_add_output_symbol
425 (bfd *, size_t *psymalloc, asymbol *);
426 static bfd_boolean default_data_link_order
427 (bfd *, struct bfd_link_info *, asection *, struct bfd_link_order *);
428 static bfd_boolean default_indirect_link_order
429 (bfd *, struct bfd_link_info *, asection *, struct bfd_link_order *,
430 bfd_boolean);
432 /* The link hash table structure is defined in bfdlink.h. It provides
433 a base hash table which the backend specific hash tables are built
434 upon. */
436 /* Routine to create an entry in the link hash table. */
438 struct bfd_hash_entry *
439 _bfd_link_hash_newfunc (struct bfd_hash_entry *entry,
440 struct bfd_hash_table *table,
441 const char *string)
443 /* Allocate the structure if it has not already been allocated by a
444 subclass. */
445 if (entry == NULL)
447 entry = bfd_hash_allocate (table, sizeof (struct bfd_link_hash_entry));
448 if (entry == NULL)
449 return entry;
452 /* Call the allocation method of the superclass. */
453 entry = bfd_hash_newfunc (entry, table, string);
454 if (entry)
456 struct bfd_link_hash_entry *h = (struct bfd_link_hash_entry *) entry;
458 /* Initialize the local fields. */
459 h->type = bfd_link_hash_new;
460 memset (&h->u.undef.next, 0,
461 (sizeof (struct bfd_link_hash_entry)
462 - offsetof (struct bfd_link_hash_entry, u.undef.next)));
465 return entry;
468 /* Initialize a link hash table. The BFD argument is the one
469 responsible for creating this table. */
471 bfd_boolean
472 _bfd_link_hash_table_init
473 (struct bfd_link_hash_table *table,
474 bfd *abfd,
475 struct bfd_hash_entry *(*newfunc) (struct bfd_hash_entry *,
476 struct bfd_hash_table *,
477 const char *),
478 unsigned int entsize)
480 table->creator = abfd->xvec;
481 table->undefs = NULL;
482 table->undefs_tail = NULL;
483 table->type = bfd_link_generic_hash_table;
485 return bfd_hash_table_init (&table->table, newfunc, entsize);
488 /* Look up a symbol in a link hash table. If follow is TRUE, we
489 follow bfd_link_hash_indirect and bfd_link_hash_warning links to
490 the real symbol. */
492 struct bfd_link_hash_entry *
493 bfd_link_hash_lookup (struct bfd_link_hash_table *table,
494 const char *string,
495 bfd_boolean create,
496 bfd_boolean copy,
497 bfd_boolean follow)
499 struct bfd_link_hash_entry *ret;
501 ret = ((struct bfd_link_hash_entry *)
502 bfd_hash_lookup (&table->table, string, create, copy));
504 if (follow && ret != NULL)
506 while (ret->type == bfd_link_hash_indirect
507 || ret->type == bfd_link_hash_warning)
508 ret = ret->u.i.link;
511 return ret;
514 /* Look up a symbol in the main linker hash table if the symbol might
515 be wrapped. This should only be used for references to an
516 undefined symbol, not for definitions of a symbol. */
518 struct bfd_link_hash_entry *
519 bfd_wrapped_link_hash_lookup (bfd *abfd,
520 struct bfd_link_info *info,
521 const char *string,
522 bfd_boolean create,
523 bfd_boolean copy,
524 bfd_boolean follow)
526 bfd_size_type amt;
528 if (info->wrap_hash != NULL)
530 const char *l;
531 char prefix = '\0';
533 l = string;
534 if (*l == bfd_get_symbol_leading_char (abfd) || *l == info->wrap_char)
536 prefix = *l;
537 ++l;
540 #undef WRAP
541 #define WRAP "__wrap_"
543 if (bfd_hash_lookup (info->wrap_hash, l, FALSE, FALSE) != NULL)
545 char *n;
546 struct bfd_link_hash_entry *h;
548 /* This symbol is being wrapped. We want to replace all
549 references to SYM with references to __wrap_SYM. */
551 amt = strlen (l) + sizeof WRAP + 1;
552 n = bfd_malloc (amt);
553 if (n == NULL)
554 return NULL;
556 n[0] = prefix;
557 n[1] = '\0';
558 strcat (n, WRAP);
559 strcat (n, l);
560 h = bfd_link_hash_lookup (info->hash, n, create, TRUE, follow);
561 free (n);
562 return h;
565 #undef WRAP
567 #undef REAL
568 #define REAL "__real_"
570 if (*l == '_'
571 && CONST_STRNEQ (l, REAL)
572 && bfd_hash_lookup (info->wrap_hash, l + sizeof REAL - 1,
573 FALSE, FALSE) != NULL)
575 char *n;
576 struct bfd_link_hash_entry *h;
578 /* This is a reference to __real_SYM, where SYM is being
579 wrapped. We want to replace all references to __real_SYM
580 with references to SYM. */
582 amt = strlen (l + sizeof REAL - 1) + 2;
583 n = bfd_malloc (amt);
584 if (n == NULL)
585 return NULL;
587 n[0] = prefix;
588 n[1] = '\0';
589 strcat (n, l + sizeof REAL - 1);
590 h = bfd_link_hash_lookup (info->hash, n, create, TRUE, follow);
591 free (n);
592 return h;
595 #undef REAL
598 return bfd_link_hash_lookup (info->hash, string, create, copy, follow);
601 /* Traverse a generic link hash table. The only reason this is not a
602 macro is to do better type checking. This code presumes that an
603 argument passed as a struct bfd_hash_entry * may be caught as a
604 struct bfd_link_hash_entry * with no explicit cast required on the
605 call. */
607 void
608 bfd_link_hash_traverse
609 (struct bfd_link_hash_table *table,
610 bfd_boolean (*func) (struct bfd_link_hash_entry *, void *),
611 void *info)
613 bfd_hash_traverse (&table->table,
614 (bfd_boolean (*) (struct bfd_hash_entry *, void *)) func,
615 info);
618 /* Add a symbol to the linker hash table undefs list. */
620 void
621 bfd_link_add_undef (struct bfd_link_hash_table *table,
622 struct bfd_link_hash_entry *h)
624 BFD_ASSERT (h->u.undef.next == NULL);
625 if (table->undefs_tail != NULL)
626 table->undefs_tail->u.undef.next = h;
627 if (table->undefs == NULL)
628 table->undefs = h;
629 table->undefs_tail = h;
632 /* The undefs list was designed so that in normal use we don't need to
633 remove entries. However, if symbols on the list are changed from
634 bfd_link_hash_undefined to either bfd_link_hash_undefweak or
635 bfd_link_hash_new for some reason, then they must be removed from the
636 list. Failure to do so might result in the linker attempting to add
637 the symbol to the list again at a later stage. */
639 void
640 bfd_link_repair_undef_list (struct bfd_link_hash_table *table)
642 struct bfd_link_hash_entry **pun;
644 pun = &table->undefs;
645 while (*pun != NULL)
647 struct bfd_link_hash_entry *h = *pun;
649 if (h->type == bfd_link_hash_new
650 || h->type == bfd_link_hash_undefweak)
652 *pun = h->u.undef.next;
653 h->u.undef.next = NULL;
654 if (h == table->undefs_tail)
656 if (pun == &table->undefs)
657 table->undefs_tail = NULL;
658 else
659 /* pun points at an u.undef.next field. Go back to
660 the start of the link_hash_entry. */
661 table->undefs_tail = (struct bfd_link_hash_entry *)
662 ((char *) pun - ((char *) &h->u.undef.next - (char *) h));
663 break;
666 else
667 pun = &h->u.undef.next;
671 /* Routine to create an entry in a generic link hash table. */
673 struct bfd_hash_entry *
674 _bfd_generic_link_hash_newfunc (struct bfd_hash_entry *entry,
675 struct bfd_hash_table *table,
676 const char *string)
678 /* Allocate the structure if it has not already been allocated by a
679 subclass. */
680 if (entry == NULL)
682 entry =
683 bfd_hash_allocate (table, sizeof (struct generic_link_hash_entry));
684 if (entry == NULL)
685 return entry;
688 /* Call the allocation method of the superclass. */
689 entry = _bfd_link_hash_newfunc (entry, table, string);
690 if (entry)
692 struct generic_link_hash_entry *ret;
694 /* Set local fields. */
695 ret = (struct generic_link_hash_entry *) entry;
696 ret->written = FALSE;
697 ret->sym = NULL;
700 return entry;
703 /* Create a generic link hash table. */
705 struct bfd_link_hash_table *
706 _bfd_generic_link_hash_table_create (bfd *abfd)
708 struct generic_link_hash_table *ret;
709 bfd_size_type amt = sizeof (struct generic_link_hash_table);
711 ret = bfd_malloc (amt);
712 if (ret == NULL)
713 return NULL;
714 if (! _bfd_link_hash_table_init (&ret->root, abfd,
715 _bfd_generic_link_hash_newfunc,
716 sizeof (struct generic_link_hash_entry)))
718 free (ret);
719 return NULL;
721 return &ret->root;
724 void
725 _bfd_generic_link_hash_table_free (struct bfd_link_hash_table *hash)
727 struct generic_link_hash_table *ret
728 = (struct generic_link_hash_table *) hash;
730 bfd_hash_table_free (&ret->root.table);
731 free (ret);
734 /* Grab the symbols for an object file when doing a generic link. We
735 store the symbols in the outsymbols field. We need to keep them
736 around for the entire link to ensure that we only read them once.
737 If we read them multiple times, we might wind up with relocs and
738 the hash table pointing to different instances of the symbol
739 structure. */
741 static bfd_boolean
742 generic_link_read_symbols (bfd *abfd)
744 if (bfd_get_outsymbols (abfd) == NULL)
746 long symsize;
747 long symcount;
749 symsize = bfd_get_symtab_upper_bound (abfd);
750 if (symsize < 0)
751 return FALSE;
752 bfd_get_outsymbols (abfd) = bfd_alloc (abfd, symsize);
753 if (bfd_get_outsymbols (abfd) == NULL && symsize != 0)
754 return FALSE;
755 symcount = bfd_canonicalize_symtab (abfd, bfd_get_outsymbols (abfd));
756 if (symcount < 0)
757 return FALSE;
758 bfd_get_symcount (abfd) = symcount;
761 return TRUE;
764 /* Generic function to add symbols to from an object file to the
765 global hash table. This version does not automatically collect
766 constructors by name. */
768 bfd_boolean
769 _bfd_generic_link_add_symbols (bfd *abfd, struct bfd_link_info *info)
771 return generic_link_add_symbols (abfd, info, FALSE);
774 /* Generic function to add symbols from an object file to the global
775 hash table. This version automatically collects constructors by
776 name, as the collect2 program does. It should be used for any
777 target which does not provide some other mechanism for setting up
778 constructors and destructors; these are approximately those targets
779 for which gcc uses collect2 and do not support stabs. */
781 bfd_boolean
782 _bfd_generic_link_add_symbols_collect (bfd *abfd, struct bfd_link_info *info)
784 return generic_link_add_symbols (abfd, info, TRUE);
787 /* Indicate that we are only retrieving symbol values from this
788 section. We want the symbols to act as though the values in the
789 file are absolute. */
791 void
792 _bfd_generic_link_just_syms (asection *sec,
793 struct bfd_link_info *info ATTRIBUTE_UNUSED)
795 sec->output_section = bfd_abs_section_ptr;
796 sec->output_offset = sec->vma;
799 /* Add symbols from an object file to the global hash table. */
801 static bfd_boolean
802 generic_link_add_symbols (bfd *abfd,
803 struct bfd_link_info *info,
804 bfd_boolean collect)
806 bfd_boolean ret;
808 switch (bfd_get_format (abfd))
810 case bfd_object:
811 ret = generic_link_add_object_symbols (abfd, info, collect);
812 break;
813 case bfd_archive:
814 ret = (_bfd_generic_link_add_archive_symbols
815 (abfd, info,
816 (collect
817 ? generic_link_check_archive_element_collect
818 : generic_link_check_archive_element_no_collect)));
819 break;
820 default:
821 bfd_set_error (bfd_error_wrong_format);
822 ret = FALSE;
825 return ret;
828 /* Add symbols from an object file to the global hash table. */
830 static bfd_boolean
831 generic_link_add_object_symbols (bfd *abfd,
832 struct bfd_link_info *info,
833 bfd_boolean collect)
835 bfd_size_type symcount;
836 struct bfd_symbol **outsyms;
838 if (! generic_link_read_symbols (abfd))
839 return FALSE;
840 symcount = _bfd_generic_link_get_symcount (abfd);
841 outsyms = _bfd_generic_link_get_symbols (abfd);
842 return generic_link_add_symbol_list (abfd, info, symcount, outsyms, collect);
845 /* We build a hash table of all symbols defined in an archive. */
847 /* An archive symbol may be defined by multiple archive elements.
848 This linked list is used to hold the elements. */
850 struct archive_list
852 struct archive_list *next;
853 unsigned int indx;
856 /* An entry in an archive hash table. */
858 struct archive_hash_entry
860 struct bfd_hash_entry root;
861 /* Where the symbol is defined. */
862 struct archive_list *defs;
865 /* An archive hash table itself. */
867 struct archive_hash_table
869 struct bfd_hash_table table;
872 /* Create a new entry for an archive hash table. */
874 static struct bfd_hash_entry *
875 archive_hash_newfunc (struct bfd_hash_entry *entry,
876 struct bfd_hash_table *table,
877 const char *string)
879 struct archive_hash_entry *ret = (struct archive_hash_entry *) entry;
881 /* Allocate the structure if it has not already been allocated by a
882 subclass. */
883 if (ret == NULL)
884 ret = bfd_hash_allocate (table, sizeof (struct archive_hash_entry));
885 if (ret == NULL)
886 return NULL;
888 /* Call the allocation method of the superclass. */
889 ret = ((struct archive_hash_entry *)
890 bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));
892 if (ret)
894 /* Initialize the local fields. */
895 ret->defs = NULL;
898 return &ret->root;
901 /* Initialize an archive hash table. */
903 static bfd_boolean
904 archive_hash_table_init
905 (struct archive_hash_table *table,
906 struct bfd_hash_entry *(*newfunc) (struct bfd_hash_entry *,
907 struct bfd_hash_table *,
908 const char *),
909 unsigned int entsize)
911 return bfd_hash_table_init (&table->table, newfunc, entsize);
914 /* Look up an entry in an archive hash table. */
916 #define archive_hash_lookup(t, string, create, copy) \
917 ((struct archive_hash_entry *) \
918 bfd_hash_lookup (&(t)->table, (string), (create), (copy)))
920 /* Allocate space in an archive hash table. */
922 #define archive_hash_allocate(t, size) bfd_hash_allocate (&(t)->table, (size))
924 /* Free an archive hash table. */
926 #define archive_hash_table_free(t) bfd_hash_table_free (&(t)->table)
928 /* Generic function to add symbols from an archive file to the global
929 hash file. This function presumes that the archive symbol table
930 has already been read in (this is normally done by the
931 bfd_check_format entry point). It looks through the undefined and
932 common symbols and searches the archive symbol table for them. If
933 it finds an entry, it includes the associated object file in the
934 link.
936 The old linker looked through the archive symbol table for
937 undefined symbols. We do it the other way around, looking through
938 undefined symbols for symbols defined in the archive. The
939 advantage of the newer scheme is that we only have to look through
940 the list of undefined symbols once, whereas the old method had to
941 re-search the symbol table each time a new object file was added.
943 The CHECKFN argument is used to see if an object file should be
944 included. CHECKFN should set *PNEEDED to TRUE if the object file
945 should be included, and must also call the bfd_link_info
946 add_archive_element callback function and handle adding the symbols
947 to the global hash table. CHECKFN should only return FALSE if some
948 sort of error occurs.
950 For some formats, such as a.out, it is possible to look through an
951 object file but not actually include it in the link. The
952 archive_pass field in a BFD is used to avoid checking the symbols
953 of an object files too many times. When an object is included in
954 the link, archive_pass is set to -1. If an object is scanned but
955 not included, archive_pass is set to the pass number. The pass
956 number is incremented each time a new object file is included. The
957 pass number is used because when a new object file is included it
958 may create new undefined symbols which cause a previously examined
959 object file to be included. */
961 bfd_boolean
962 _bfd_generic_link_add_archive_symbols
963 (bfd *abfd,
964 struct bfd_link_info *info,
965 bfd_boolean (*checkfn) (bfd *, struct bfd_link_info *, bfd_boolean *))
967 carsym *arsyms;
968 carsym *arsym_end;
969 register carsym *arsym;
970 int pass;
971 struct archive_hash_table arsym_hash;
972 unsigned int indx;
973 struct bfd_link_hash_entry **pundef;
975 if (! bfd_has_map (abfd))
977 /* An empty archive is a special case. */
978 if (bfd_openr_next_archived_file (abfd, NULL) == NULL)
979 return TRUE;
980 bfd_set_error (bfd_error_no_armap);
981 return FALSE;
984 arsyms = bfd_ardata (abfd)->symdefs;
985 arsym_end = arsyms + bfd_ardata (abfd)->symdef_count;
987 /* In order to quickly determine whether an symbol is defined in
988 this archive, we build a hash table of the symbols. */
989 if (! archive_hash_table_init (&arsym_hash, archive_hash_newfunc,
990 sizeof (struct archive_hash_entry)))
991 return FALSE;
992 for (arsym = arsyms, indx = 0; arsym < arsym_end; arsym++, indx++)
994 struct archive_hash_entry *arh;
995 struct archive_list *l, **pp;
997 arh = archive_hash_lookup (&arsym_hash, arsym->name, TRUE, FALSE);
998 if (arh == NULL)
999 goto error_return;
1000 l = ((struct archive_list *)
1001 archive_hash_allocate (&arsym_hash, sizeof (struct archive_list)));
1002 if (l == NULL)
1003 goto error_return;
1004 l->indx = indx;
1005 for (pp = &arh->defs; *pp != NULL; pp = &(*pp)->next)
1007 *pp = l;
1008 l->next = NULL;
1011 /* The archive_pass field in the archive itself is used to
1012 initialize PASS, sine we may search the same archive multiple
1013 times. */
1014 pass = abfd->archive_pass + 1;
1016 /* New undefined symbols are added to the end of the list, so we
1017 only need to look through it once. */
1018 pundef = &info->hash->undefs;
1019 while (*pundef != NULL)
1021 struct bfd_link_hash_entry *h;
1022 struct archive_hash_entry *arh;
1023 struct archive_list *l;
1025 h = *pundef;
1027 /* When a symbol is defined, it is not necessarily removed from
1028 the list. */
1029 if (h->type != bfd_link_hash_undefined
1030 && h->type != bfd_link_hash_common)
1032 /* Remove this entry from the list, for general cleanliness
1033 and because we are going to look through the list again
1034 if we search any more libraries. We can't remove the
1035 entry if it is the tail, because that would lose any
1036 entries we add to the list later on (it would also cause
1037 us to lose track of whether the symbol has been
1038 referenced). */
1039 if (*pundef != info->hash->undefs_tail)
1040 *pundef = (*pundef)->u.undef.next;
1041 else
1042 pundef = &(*pundef)->u.undef.next;
1043 continue;
1046 /* Look for this symbol in the archive symbol map. */
1047 arh = archive_hash_lookup (&arsym_hash, h->root.string, FALSE, FALSE);
1048 if (arh == NULL)
1050 /* If we haven't found the exact symbol we're looking for,
1051 let's look for its import thunk */
1052 if (info->pei386_auto_import)
1054 bfd_size_type amt = strlen (h->root.string) + 10;
1055 char *buf = bfd_malloc (amt);
1056 if (buf == NULL)
1057 return FALSE;
1059 sprintf (buf, "__imp_%s", h->root.string);
1060 arh = archive_hash_lookup (&arsym_hash, buf, FALSE, FALSE);
1061 free(buf);
1063 if (arh == NULL)
1065 pundef = &(*pundef)->u.undef.next;
1066 continue;
1069 /* Look at all the objects which define this symbol. */
1070 for (l = arh->defs; l != NULL; l = l->next)
1072 bfd *element;
1073 bfd_boolean needed;
1075 /* If the symbol has gotten defined along the way, quit. */
1076 if (h->type != bfd_link_hash_undefined
1077 && h->type != bfd_link_hash_common)
1078 break;
1080 element = bfd_get_elt_at_index (abfd, l->indx);
1081 if (element == NULL)
1082 goto error_return;
1084 /* If we've already included this element, or if we've
1085 already checked it on this pass, continue. */
1086 if (element->archive_pass == -1
1087 || element->archive_pass == pass)
1088 continue;
1090 /* If we can't figure this element out, just ignore it. */
1091 if (! bfd_check_format (element, bfd_object))
1093 element->archive_pass = -1;
1094 continue;
1097 /* CHECKFN will see if this element should be included, and
1098 go ahead and include it if appropriate. */
1099 if (! (*checkfn) (element, info, &needed))
1100 goto error_return;
1102 if (! needed)
1103 element->archive_pass = pass;
1104 else
1106 element->archive_pass = -1;
1108 /* Increment the pass count to show that we may need to
1109 recheck object files which were already checked. */
1110 ++pass;
1114 pundef = &(*pundef)->u.undef.next;
1117 archive_hash_table_free (&arsym_hash);
1119 /* Save PASS in case we are called again. */
1120 abfd->archive_pass = pass;
1122 return TRUE;
1124 error_return:
1125 archive_hash_table_free (&arsym_hash);
1126 return FALSE;
1129 /* See if we should include an archive element. This version is used
1130 when we do not want to automatically collect constructors based on
1131 the symbol name, presumably because we have some other mechanism
1132 for finding them. */
1134 static bfd_boolean
1135 generic_link_check_archive_element_no_collect (
1136 bfd *abfd,
1137 struct bfd_link_info *info,
1138 bfd_boolean *pneeded)
1140 return generic_link_check_archive_element (abfd, info, pneeded, FALSE);
1143 /* See if we should include an archive element. This version is used
1144 when we want to automatically collect constructors based on the
1145 symbol name, as collect2 does. */
1147 static bfd_boolean
1148 generic_link_check_archive_element_collect (bfd *abfd,
1149 struct bfd_link_info *info,
1150 bfd_boolean *pneeded)
1152 return generic_link_check_archive_element (abfd, info, pneeded, TRUE);
1155 /* See if we should include an archive element. Optionally collect
1156 constructors. */
1158 static bfd_boolean
1159 generic_link_check_archive_element (bfd *abfd,
1160 struct bfd_link_info *info,
1161 bfd_boolean *pneeded,
1162 bfd_boolean collect)
1164 asymbol **pp, **ppend;
1166 *pneeded = FALSE;
1168 if (! generic_link_read_symbols (abfd))
1169 return FALSE;
1171 pp = _bfd_generic_link_get_symbols (abfd);
1172 ppend = pp + _bfd_generic_link_get_symcount (abfd);
1173 for (; pp < ppend; pp++)
1175 asymbol *p;
1176 struct bfd_link_hash_entry *h;
1178 p = *pp;
1180 /* We are only interested in globally visible symbols. */
1181 if (! bfd_is_com_section (p->section)
1182 && (p->flags & (BSF_GLOBAL | BSF_INDIRECT | BSF_WEAK)) == 0)
1183 continue;
1185 /* We are only interested if we know something about this
1186 symbol, and it is undefined or common. An undefined weak
1187 symbol (type bfd_link_hash_undefweak) is not considered to be
1188 a reference when pulling files out of an archive. See the
1189 SVR4 ABI, p. 4-27. */
1190 h = bfd_link_hash_lookup (info->hash, bfd_asymbol_name (p), FALSE,
1191 FALSE, TRUE);
1192 if (h == NULL
1193 || (h->type != bfd_link_hash_undefined
1194 && h->type != bfd_link_hash_common))
1195 continue;
1197 /* P is a symbol we are looking for. */
1199 if (! bfd_is_com_section (p->section))
1201 bfd_size_type symcount;
1202 asymbol **symbols;
1204 /* This object file defines this symbol, so pull it in. */
1205 if (! (*info->callbacks->add_archive_element) (info, abfd,
1206 bfd_asymbol_name (p)))
1207 return FALSE;
1208 symcount = _bfd_generic_link_get_symcount (abfd);
1209 symbols = _bfd_generic_link_get_symbols (abfd);
1210 if (! generic_link_add_symbol_list (abfd, info, symcount,
1211 symbols, collect))
1212 return FALSE;
1213 *pneeded = TRUE;
1214 return TRUE;
1217 /* P is a common symbol. */
1219 if (h->type == bfd_link_hash_undefined)
1221 bfd *symbfd;
1222 bfd_vma size;
1223 unsigned int power;
1225 symbfd = h->u.undef.abfd;
1226 if (symbfd == NULL)
1228 /* This symbol was created as undefined from outside
1229 BFD. We assume that we should link in the object
1230 file. This is for the -u option in the linker. */
1231 if (! (*info->callbacks->add_archive_element)
1232 (info, abfd, bfd_asymbol_name (p)))
1233 return FALSE;
1234 *pneeded = TRUE;
1235 return TRUE;
1238 /* Turn the symbol into a common symbol but do not link in
1239 the object file. This is how a.out works. Object
1240 formats that require different semantics must implement
1241 this function differently. This symbol is already on the
1242 undefs list. We add the section to a common section
1243 attached to symbfd to ensure that it is in a BFD which
1244 will be linked in. */
1245 h->type = bfd_link_hash_common;
1246 h->u.c.p =
1247 bfd_hash_allocate (&info->hash->table,
1248 sizeof (struct bfd_link_hash_common_entry));
1249 if (h->u.c.p == NULL)
1250 return FALSE;
1252 size = bfd_asymbol_value (p);
1253 h->u.c.size = size;
1255 power = bfd_log2 (size);
1256 if (power > 4)
1257 power = 4;
1258 h->u.c.p->alignment_power = power;
1260 if (p->section == bfd_com_section_ptr)
1261 h->u.c.p->section = bfd_make_section_old_way (symbfd, "COMMON");
1262 else
1263 h->u.c.p->section = bfd_make_section_old_way (symbfd,
1264 p->section->name);
1265 h->u.c.p->section->flags = SEC_ALLOC;
1267 else
1269 /* Adjust the size of the common symbol if necessary. This
1270 is how a.out works. Object formats that require
1271 different semantics must implement this function
1272 differently. */
1273 if (bfd_asymbol_value (p) > h->u.c.size)
1274 h->u.c.size = bfd_asymbol_value (p);
1278 /* This archive element is not needed. */
1279 return TRUE;
1282 /* Add the symbols from an object file to the global hash table. ABFD
1283 is the object file. INFO is the linker information. SYMBOL_COUNT
1284 is the number of symbols. SYMBOLS is the list of symbols. COLLECT
1285 is TRUE if constructors should be automatically collected by name
1286 as is done by collect2. */
1288 static bfd_boolean
1289 generic_link_add_symbol_list (bfd *abfd,
1290 struct bfd_link_info *info,
1291 bfd_size_type symbol_count,
1292 asymbol **symbols,
1293 bfd_boolean collect)
1295 asymbol **pp, **ppend;
1297 pp = symbols;
1298 ppend = symbols + symbol_count;
1299 for (; pp < ppend; pp++)
1301 asymbol *p;
1303 p = *pp;
1305 if ((p->flags & (BSF_INDIRECT
1306 | BSF_WARNING
1307 | BSF_GLOBAL
1308 | BSF_CONSTRUCTOR
1309 | BSF_WEAK)) != 0
1310 || bfd_is_und_section (bfd_get_section (p))
1311 || bfd_is_com_section (bfd_get_section (p))
1312 || bfd_is_ind_section (bfd_get_section (p)))
1314 const char *name;
1315 const char *string;
1316 struct generic_link_hash_entry *h;
1317 struct bfd_link_hash_entry *bh;
1319 string = name = bfd_asymbol_name (p);
1320 if (((p->flags & BSF_INDIRECT) != 0
1321 || bfd_is_ind_section (p->section))
1322 && pp + 1 < ppend)
1324 pp++;
1325 string = bfd_asymbol_name (*pp);
1327 else if ((p->flags & BSF_WARNING) != 0
1328 && pp + 1 < ppend)
1330 /* The name of P is actually the warning string, and the
1331 next symbol is the one to warn about. */
1332 pp++;
1333 name = bfd_asymbol_name (*pp);
1336 bh = NULL;
1337 if (! (_bfd_generic_link_add_one_symbol
1338 (info, abfd, name, p->flags, bfd_get_section (p),
1339 p->value, string, FALSE, collect, &bh)))
1340 return FALSE;
1341 h = (struct generic_link_hash_entry *) bh;
1343 /* If this is a constructor symbol, and the linker didn't do
1344 anything with it, then we want to just pass the symbol
1345 through to the output file. This will happen when
1346 linking with -r. */
1347 if ((p->flags & BSF_CONSTRUCTOR) != 0
1348 && (h == NULL || h->root.type == bfd_link_hash_new))
1350 p->udata.p = NULL;
1351 continue;
1354 /* Save the BFD symbol so that we don't lose any backend
1355 specific information that may be attached to it. We only
1356 want this one if it gives more information than the
1357 existing one; we don't want to replace a defined symbol
1358 with an undefined one. This routine may be called with a
1359 hash table other than the generic hash table, so we only
1360 do this if we are certain that the hash table is a
1361 generic one. */
1362 if (info->hash->creator == abfd->xvec)
1364 if (h->sym == NULL
1365 || (! bfd_is_und_section (bfd_get_section (p))
1366 && (! bfd_is_com_section (bfd_get_section (p))
1367 || bfd_is_und_section (bfd_get_section (h->sym)))))
1369 h->sym = p;
1370 /* BSF_OLD_COMMON is a hack to support COFF reloc
1371 reading, and it should go away when the COFF
1372 linker is switched to the new version. */
1373 if (bfd_is_com_section (bfd_get_section (p)))
1374 p->flags |= BSF_OLD_COMMON;
1378 /* Store a back pointer from the symbol to the hash
1379 table entry for the benefit of relaxation code until
1380 it gets rewritten to not use asymbol structures.
1381 Setting this is also used to check whether these
1382 symbols were set up by the generic linker. */
1383 p->udata.p = h;
1387 return TRUE;
1390 /* We use a state table to deal with adding symbols from an object
1391 file. The first index into the state table describes the symbol
1392 from the object file. The second index into the state table is the
1393 type of the symbol in the hash table. */
1395 /* The symbol from the object file is turned into one of these row
1396 values. */
1398 enum link_row
1400 UNDEF_ROW, /* Undefined. */
1401 UNDEFW_ROW, /* Weak undefined. */
1402 DEF_ROW, /* Defined. */
1403 DEFW_ROW, /* Weak defined. */
1404 COMMON_ROW, /* Common. */
1405 INDR_ROW, /* Indirect. */
1406 WARN_ROW, /* Warning. */
1407 SET_ROW /* Member of set. */
1410 /* apparently needed for Hitachi 3050R(HI-UX/WE2)? */
1411 #undef FAIL
1413 /* The actions to take in the state table. */
1415 enum link_action
1417 FAIL, /* Abort. */
1418 UND, /* Mark symbol undefined. */
1419 WEAK, /* Mark symbol weak undefined. */
1420 DEF, /* Mark symbol defined. */
1421 DEFW, /* Mark symbol weak defined. */
1422 COM, /* Mark symbol common. */
1423 REF, /* Mark defined symbol referenced. */
1424 CREF, /* Possibly warn about common reference to defined symbol. */
1425 CDEF, /* Define existing common symbol. */
1426 NOACT, /* No action. */
1427 BIG, /* Mark symbol common using largest size. */
1428 MDEF, /* Multiple definition error. */
1429 MIND, /* Multiple indirect symbols. */
1430 IND, /* Make indirect symbol. */
1431 CIND, /* Make indirect symbol from existing common symbol. */
1432 SET, /* Add value to set. */
1433 MWARN, /* Make warning symbol. */
1434 WARN, /* Issue warning. */
1435 CWARN, /* Warn if referenced, else MWARN. */
1436 CYCLE, /* Repeat with symbol pointed to. */
1437 REFC, /* Mark indirect symbol referenced and then CYCLE. */
1438 WARNC /* Issue warning and then CYCLE. */
1441 /* The state table itself. The first index is a link_row and the
1442 second index is a bfd_link_hash_type. */
1444 static const enum link_action link_action[8][8] =
1446 /* current\prev new undef undefw def defw com indr warn */
1447 /* UNDEF_ROW */ {UND, NOACT, UND, REF, REF, NOACT, REFC, WARNC },
1448 /* UNDEFW_ROW */ {WEAK, NOACT, NOACT, REF, REF, NOACT, REFC, WARNC },
1449 /* DEF_ROW */ {DEF, DEF, DEF, MDEF, DEF, CDEF, MDEF, CYCLE },
1450 /* DEFW_ROW */ {DEFW, DEFW, DEFW, NOACT, NOACT, NOACT, NOACT, CYCLE },
1451 /* COMMON_ROW */ {COM, COM, COM, CREF, COM, BIG, REFC, WARNC },
1452 /* INDR_ROW */ {IND, IND, IND, MDEF, IND, CIND, MIND, CYCLE },
1453 /* WARN_ROW */ {MWARN, WARN, WARN, CWARN, CWARN, WARN, CWARN, NOACT },
1454 /* SET_ROW */ {SET, SET, SET, SET, SET, SET, CYCLE, CYCLE }
1457 /* Most of the entries in the LINK_ACTION table are straightforward,
1458 but a few are somewhat subtle.
1460 A reference to an indirect symbol (UNDEF_ROW/indr or
1461 UNDEFW_ROW/indr) is counted as a reference both to the indirect
1462 symbol and to the symbol the indirect symbol points to.
1464 A reference to a warning symbol (UNDEF_ROW/warn or UNDEFW_ROW/warn)
1465 causes the warning to be issued.
1467 A common definition of an indirect symbol (COMMON_ROW/indr) is
1468 treated as a multiple definition error. Likewise for an indirect
1469 definition of a common symbol (INDR_ROW/com).
1471 An indirect definition of a warning (INDR_ROW/warn) does not cause
1472 the warning to be issued.
1474 If a warning is created for an indirect symbol (WARN_ROW/indr) no
1475 warning is created for the symbol the indirect symbol points to.
1477 Adding an entry to a set does not count as a reference to a set,
1478 and no warning is issued (SET_ROW/warn). */
1480 /* Return the BFD in which a hash entry has been defined, if known. */
1482 static bfd *
1483 hash_entry_bfd (struct bfd_link_hash_entry *h)
1485 while (h->type == bfd_link_hash_warning)
1486 h = h->u.i.link;
1487 switch (h->type)
1489 default:
1490 return NULL;
1491 case bfd_link_hash_undefined:
1492 case bfd_link_hash_undefweak:
1493 return h->u.undef.abfd;
1494 case bfd_link_hash_defined:
1495 case bfd_link_hash_defweak:
1496 return h->u.def.section->owner;
1497 case bfd_link_hash_common:
1498 return h->u.c.p->section->owner;
1500 /*NOTREACHED*/
1503 /* Add a symbol to the global hash table.
1504 ABFD is the BFD the symbol comes from.
1505 NAME is the name of the symbol.
1506 FLAGS is the BSF_* bits associated with the symbol.
1507 SECTION is the section in which the symbol is defined; this may be
1508 bfd_und_section_ptr or bfd_com_section_ptr.
1509 VALUE is the value of the symbol, relative to the section.
1510 STRING is used for either an indirect symbol, in which case it is
1511 the name of the symbol to indirect to, or a warning symbol, in
1512 which case it is the warning string.
1513 COPY is TRUE if NAME or STRING must be copied into locally
1514 allocated memory if they need to be saved.
1515 COLLECT is TRUE if we should automatically collect gcc constructor
1516 or destructor names as collect2 does.
1517 HASHP, if not NULL, is a place to store the created hash table
1518 entry; if *HASHP is not NULL, the caller has already looked up
1519 the hash table entry, and stored it in *HASHP. */
1521 bfd_boolean
1522 _bfd_generic_link_add_one_symbol (struct bfd_link_info *info,
1523 bfd *abfd,
1524 const char *name,
1525 flagword flags,
1526 asection *section,
1527 bfd_vma value,
1528 const char *string,
1529 bfd_boolean copy,
1530 bfd_boolean collect,
1531 struct bfd_link_hash_entry **hashp)
1533 enum link_row row;
1534 struct bfd_link_hash_entry *h;
1535 bfd_boolean cycle;
1537 if (bfd_is_ind_section (section)
1538 || (flags & BSF_INDIRECT) != 0)
1539 row = INDR_ROW;
1540 else if ((flags & BSF_WARNING) != 0)
1541 row = WARN_ROW;
1542 else if ((flags & BSF_CONSTRUCTOR) != 0)
1543 row = SET_ROW;
1544 else if (bfd_is_und_section (section))
1546 if ((flags & BSF_WEAK) != 0)
1547 row = UNDEFW_ROW;
1548 else
1549 row = UNDEF_ROW;
1551 else if ((flags & BSF_WEAK) != 0)
1552 row = DEFW_ROW;
1553 else if (bfd_is_com_section (section))
1554 row = COMMON_ROW;
1555 else
1556 row = DEF_ROW;
1558 if (hashp != NULL && *hashp != NULL)
1559 h = *hashp;
1560 else
1562 if (row == UNDEF_ROW || row == UNDEFW_ROW)
1563 h = bfd_wrapped_link_hash_lookup (abfd, info, name, TRUE, copy, FALSE);
1564 else
1565 h = bfd_link_hash_lookup (info->hash, name, TRUE, copy, FALSE);
1566 if (h == NULL)
1568 if (hashp != NULL)
1569 *hashp = NULL;
1570 return FALSE;
1574 if (info->notice_all
1575 || (info->notice_hash != NULL
1576 && bfd_hash_lookup (info->notice_hash, name, FALSE, FALSE) != NULL))
1578 if (! (*info->callbacks->notice) (info, h->root.string, abfd, section,
1579 value))
1580 return FALSE;
1583 if (hashp != NULL)
1584 *hashp = h;
1588 enum link_action action;
1590 cycle = FALSE;
1591 action = link_action[(int) row][(int) h->type];
1592 switch (action)
1594 case FAIL:
1595 abort ();
1597 case NOACT:
1598 /* Do nothing. */
1599 break;
1601 case UND:
1602 /* Make a new undefined symbol. */
1603 h->type = bfd_link_hash_undefined;
1604 h->u.undef.abfd = abfd;
1605 bfd_link_add_undef (info->hash, h);
1606 break;
1608 case WEAK:
1609 /* Make a new weak undefined symbol. */
1610 h->type = bfd_link_hash_undefweak;
1611 h->u.undef.abfd = abfd;
1612 h->u.undef.weak = abfd;
1613 break;
1615 case CDEF:
1616 /* We have found a definition for a symbol which was
1617 previously common. */
1618 BFD_ASSERT (h->type == bfd_link_hash_common);
1619 if (! ((*info->callbacks->multiple_common)
1620 (info, h->root.string,
1621 h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size,
1622 abfd, bfd_link_hash_defined, 0)))
1623 return FALSE;
1624 /* Fall through. */
1625 case DEF:
1626 case DEFW:
1628 enum bfd_link_hash_type oldtype;
1630 /* Define a symbol. */
1631 oldtype = h->type;
1632 if (action == DEFW)
1633 h->type = bfd_link_hash_defweak;
1634 else
1635 h->type = bfd_link_hash_defined;
1636 h->u.def.section = section;
1637 h->u.def.value = value;
1639 /* If we have been asked to, we act like collect2 and
1640 identify all functions that might be global
1641 constructors and destructors and pass them up in a
1642 callback. We only do this for certain object file
1643 types, since many object file types can handle this
1644 automatically. */
1645 if (collect && name[0] == '_')
1647 const char *s;
1649 /* A constructor or destructor name starts like this:
1650 _+GLOBAL_[_.$][ID][_.$] where the first [_.$] and
1651 the second are the same character (we accept any
1652 character there, in case a new object file format
1653 comes along with even worse naming restrictions). */
1655 #define CONS_PREFIX "GLOBAL_"
1656 #define CONS_PREFIX_LEN (sizeof CONS_PREFIX - 1)
1658 s = name + 1;
1659 while (*s == '_')
1660 ++s;
1661 if (s[0] == 'G' && CONST_STRNEQ (s, CONS_PREFIX))
1663 char c;
1665 c = s[CONS_PREFIX_LEN + 1];
1666 if ((c == 'I' || c == 'D')
1667 && s[CONS_PREFIX_LEN] == s[CONS_PREFIX_LEN + 2])
1669 /* If this is a definition of a symbol which
1670 was previously weakly defined, we are in
1671 trouble. We have already added a
1672 constructor entry for the weak defined
1673 symbol, and now we are trying to add one
1674 for the new symbol. Fortunately, this case
1675 should never arise in practice. */
1676 if (oldtype == bfd_link_hash_defweak)
1677 abort ();
1679 if (! ((*info->callbacks->constructor)
1680 (info, c == 'I',
1681 h->root.string, abfd, section, value)))
1682 return FALSE;
1688 break;
1690 case COM:
1691 /* We have found a common definition for a symbol. */
1692 if (h->type == bfd_link_hash_new)
1693 bfd_link_add_undef (info->hash, h);
1694 h->type = bfd_link_hash_common;
1695 h->u.c.p =
1696 bfd_hash_allocate (&info->hash->table,
1697 sizeof (struct bfd_link_hash_common_entry));
1698 if (h->u.c.p == NULL)
1699 return FALSE;
1701 h->u.c.size = value;
1703 /* Select a default alignment based on the size. This may
1704 be overridden by the caller. */
1706 unsigned int power;
1708 power = bfd_log2 (value);
1709 if (power > 4)
1710 power = 4;
1711 h->u.c.p->alignment_power = power;
1714 /* The section of a common symbol is only used if the common
1715 symbol is actually allocated. It basically provides a
1716 hook for the linker script to decide which output section
1717 the common symbols should be put in. In most cases, the
1718 section of a common symbol will be bfd_com_section_ptr,
1719 the code here will choose a common symbol section named
1720 "COMMON", and the linker script will contain *(COMMON) in
1721 the appropriate place. A few targets use separate common
1722 sections for small symbols, and they require special
1723 handling. */
1724 if (section == bfd_com_section_ptr)
1726 h->u.c.p->section = bfd_make_section_old_way (abfd, "COMMON");
1727 h->u.c.p->section->flags = SEC_ALLOC;
1729 else if (section->owner != abfd)
1731 h->u.c.p->section = bfd_make_section_old_way (abfd,
1732 section->name);
1733 h->u.c.p->section->flags = SEC_ALLOC;
1735 else
1736 h->u.c.p->section = section;
1737 break;
1739 case REF:
1740 /* A reference to a defined symbol. */
1741 if (h->u.undef.next == NULL && info->hash->undefs_tail != h)
1742 h->u.undef.next = h;
1743 break;
1745 case BIG:
1746 /* We have found a common definition for a symbol which
1747 already had a common definition. Use the maximum of the
1748 two sizes, and use the section required by the larger symbol. */
1749 BFD_ASSERT (h->type == bfd_link_hash_common);
1750 if (! ((*info->callbacks->multiple_common)
1751 (info, h->root.string,
1752 h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size,
1753 abfd, bfd_link_hash_common, value)))
1754 return FALSE;
1755 if (value > h->u.c.size)
1757 unsigned int power;
1759 h->u.c.size = value;
1761 /* Select a default alignment based on the size. This may
1762 be overridden by the caller. */
1763 power = bfd_log2 (value);
1764 if (power > 4)
1765 power = 4;
1766 h->u.c.p->alignment_power = power;
1768 /* Some systems have special treatment for small commons,
1769 hence we want to select the section used by the larger
1770 symbol. This makes sure the symbol does not go in a
1771 small common section if it is now too large. */
1772 if (section == bfd_com_section_ptr)
1774 h->u.c.p->section
1775 = bfd_make_section_old_way (abfd, "COMMON");
1776 h->u.c.p->section->flags = SEC_ALLOC;
1778 else if (section->owner != abfd)
1780 h->u.c.p->section
1781 = bfd_make_section_old_way (abfd, section->name);
1782 h->u.c.p->section->flags = SEC_ALLOC;
1784 else
1785 h->u.c.p->section = section;
1787 break;
1789 case CREF:
1791 bfd *obfd;
1793 /* We have found a common definition for a symbol which
1794 was already defined. FIXME: It would nice if we could
1795 report the BFD which defined an indirect symbol, but we
1796 don't have anywhere to store the information. */
1797 if (h->type == bfd_link_hash_defined
1798 || h->type == bfd_link_hash_defweak)
1799 obfd = h->u.def.section->owner;
1800 else
1801 obfd = NULL;
1802 if (! ((*info->callbacks->multiple_common)
1803 (info, h->root.string, obfd, h->type, 0,
1804 abfd, bfd_link_hash_common, value)))
1805 return FALSE;
1807 break;
1809 case MIND:
1810 /* Multiple indirect symbols. This is OK if they both point
1811 to the same symbol. */
1812 if (strcmp (h->u.i.link->root.string, string) == 0)
1813 break;
1814 /* Fall through. */
1815 case MDEF:
1816 /* Handle a multiple definition. */
1817 if (!info->allow_multiple_definition)
1819 asection *msec = NULL;
1820 bfd_vma mval = 0;
1822 switch (h->type)
1824 case bfd_link_hash_defined:
1825 msec = h->u.def.section;
1826 mval = h->u.def.value;
1827 break;
1828 case bfd_link_hash_indirect:
1829 msec = bfd_ind_section_ptr;
1830 mval = 0;
1831 break;
1832 default:
1833 abort ();
1836 /* Ignore a redefinition of an absolute symbol to the
1837 same value; it's harmless. */
1838 if (h->type == bfd_link_hash_defined
1839 && bfd_is_abs_section (msec)
1840 && bfd_is_abs_section (section)
1841 && value == mval)
1842 break;
1844 if (! ((*info->callbacks->multiple_definition)
1845 (info, h->root.string, msec->owner, msec, mval,
1846 abfd, section, value)))
1847 return FALSE;
1849 break;
1851 case CIND:
1852 /* Create an indirect symbol from an existing common symbol. */
1853 BFD_ASSERT (h->type == bfd_link_hash_common);
1854 if (! ((*info->callbacks->multiple_common)
1855 (info, h->root.string,
1856 h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size,
1857 abfd, bfd_link_hash_indirect, 0)))
1858 return FALSE;
1859 /* Fall through. */
1860 case IND:
1861 /* Create an indirect symbol. */
1863 struct bfd_link_hash_entry *inh;
1865 /* STRING is the name of the symbol we want to indirect
1866 to. */
1867 inh = bfd_wrapped_link_hash_lookup (abfd, info, string, TRUE,
1868 copy, FALSE);
1869 if (inh == NULL)
1870 return FALSE;
1871 if (inh->type == bfd_link_hash_indirect
1872 && inh->u.i.link == h)
1874 (*_bfd_error_handler)
1875 (_("%B: indirect symbol `%s' to `%s' is a loop"),
1876 abfd, name, string);
1877 bfd_set_error (bfd_error_invalid_operation);
1878 return FALSE;
1880 if (inh->type == bfd_link_hash_new)
1882 inh->type = bfd_link_hash_undefined;
1883 inh->u.undef.abfd = abfd;
1884 bfd_link_add_undef (info->hash, inh);
1887 /* If the indirect symbol has been referenced, we need to
1888 push the reference down to the symbol we are
1889 referencing. */
1890 if (h->type != bfd_link_hash_new)
1892 row = UNDEF_ROW;
1893 cycle = TRUE;
1896 h->type = bfd_link_hash_indirect;
1897 h->u.i.link = inh;
1899 break;
1901 case SET:
1902 /* Add an entry to a set. */
1903 if (! (*info->callbacks->add_to_set) (info, h, BFD_RELOC_CTOR,
1904 abfd, section, value))
1905 return FALSE;
1906 break;
1908 case WARNC:
1909 /* Issue a warning and cycle. */
1910 if (h->u.i.warning != NULL)
1912 if (! (*info->callbacks->warning) (info, h->u.i.warning,
1913 h->root.string, abfd,
1914 NULL, 0))
1915 return FALSE;
1916 /* Only issue a warning once. */
1917 h->u.i.warning = NULL;
1919 /* Fall through. */
1920 case CYCLE:
1921 /* Try again with the referenced symbol. */
1922 h = h->u.i.link;
1923 cycle = TRUE;
1924 break;
1926 case REFC:
1927 /* A reference to an indirect symbol. */
1928 if (h->u.undef.next == NULL && info->hash->undefs_tail != h)
1929 h->u.undef.next = h;
1930 h = h->u.i.link;
1931 cycle = TRUE;
1932 break;
1934 case WARN:
1935 /* Issue a warning. */
1936 if (! (*info->callbacks->warning) (info, string, h->root.string,
1937 hash_entry_bfd (h), NULL, 0))
1938 return FALSE;
1939 break;
1941 case CWARN:
1942 /* Warn if this symbol has been referenced already,
1943 otherwise add a warning. A symbol has been referenced if
1944 the u.undef.next field is not NULL, or it is the tail of the
1945 undefined symbol list. The REF case above helps to
1946 ensure this. */
1947 if (h->u.undef.next != NULL || info->hash->undefs_tail == h)
1949 if (! (*info->callbacks->warning) (info, string, h->root.string,
1950 hash_entry_bfd (h), NULL, 0))
1951 return FALSE;
1952 break;
1954 /* Fall through. */
1955 case MWARN:
1956 /* Make a warning symbol. */
1958 struct bfd_link_hash_entry *sub;
1960 /* STRING is the warning to give. */
1961 sub = ((struct bfd_link_hash_entry *)
1962 ((*info->hash->table.newfunc)
1963 (NULL, &info->hash->table, h->root.string)));
1964 if (sub == NULL)
1965 return FALSE;
1966 *sub = *h;
1967 sub->type = bfd_link_hash_warning;
1968 sub->u.i.link = h;
1969 if (! copy)
1970 sub->u.i.warning = string;
1971 else
1973 char *w;
1974 size_t len = strlen (string) + 1;
1976 w = bfd_hash_allocate (&info->hash->table, len);
1977 if (w == NULL)
1978 return FALSE;
1979 memcpy (w, string, len);
1980 sub->u.i.warning = w;
1983 bfd_hash_replace (&info->hash->table,
1984 (struct bfd_hash_entry *) h,
1985 (struct bfd_hash_entry *) sub);
1986 if (hashp != NULL)
1987 *hashp = sub;
1989 break;
1992 while (cycle);
1994 return TRUE;
1997 /* Generic final link routine. */
1999 bfd_boolean
2000 _bfd_generic_final_link (bfd *abfd, struct bfd_link_info *info)
2002 bfd *sub;
2003 asection *o;
2004 struct bfd_link_order *p;
2005 size_t outsymalloc;
2006 struct generic_write_global_symbol_info wginfo;
2008 bfd_get_outsymbols (abfd) = NULL;
2009 bfd_get_symcount (abfd) = 0;
2010 outsymalloc = 0;
2012 /* Mark all sections which will be included in the output file. */
2013 for (o = abfd->sections; o != NULL; o = o->next)
2014 for (p = o->map_head.link_order; p != NULL; p = p->next)
2015 if (p->type == bfd_indirect_link_order)
2016 p->u.indirect.section->linker_mark = TRUE;
2018 /* Build the output symbol table. */
2019 for (sub = info->input_bfds; sub != NULL; sub = sub->link_next)
2020 if (! _bfd_generic_link_output_symbols (abfd, sub, info, &outsymalloc))
2021 return FALSE;
2023 /* Accumulate the global symbols. */
2024 wginfo.info = info;
2025 wginfo.output_bfd = abfd;
2026 wginfo.psymalloc = &outsymalloc;
2027 _bfd_generic_link_hash_traverse (_bfd_generic_hash_table (info),
2028 _bfd_generic_link_write_global_symbol,
2029 &wginfo);
2031 /* Make sure we have a trailing NULL pointer on OUTSYMBOLS. We
2032 shouldn't really need one, since we have SYMCOUNT, but some old
2033 code still expects one. */
2034 if (! generic_add_output_symbol (abfd, &outsymalloc, NULL))
2035 return FALSE;
2037 if (info->relocatable)
2039 /* Allocate space for the output relocs for each section. */
2040 for (o = abfd->sections; o != NULL; o = o->next)
2042 o->reloc_count = 0;
2043 for (p = o->map_head.link_order; p != NULL; p = p->next)
2045 if (p->type == bfd_section_reloc_link_order
2046 || p->type == bfd_symbol_reloc_link_order)
2047 ++o->reloc_count;
2048 else if (p->type == bfd_indirect_link_order)
2050 asection *input_section;
2051 bfd *input_bfd;
2052 long relsize;
2053 arelent **relocs;
2054 asymbol **symbols;
2055 long reloc_count;
2057 input_section = p->u.indirect.section;
2058 input_bfd = input_section->owner;
2059 relsize = bfd_get_reloc_upper_bound (input_bfd,
2060 input_section);
2061 if (relsize < 0)
2062 return FALSE;
2063 relocs = bfd_malloc (relsize);
2064 if (!relocs && relsize != 0)
2065 return FALSE;
2066 symbols = _bfd_generic_link_get_symbols (input_bfd);
2067 reloc_count = bfd_canonicalize_reloc (input_bfd,
2068 input_section,
2069 relocs,
2070 symbols);
2071 free (relocs);
2072 if (reloc_count < 0)
2073 return FALSE;
2074 BFD_ASSERT ((unsigned long) reloc_count
2075 == input_section->reloc_count);
2076 o->reloc_count += reloc_count;
2079 if (o->reloc_count > 0)
2081 bfd_size_type amt;
2083 amt = o->reloc_count;
2084 amt *= sizeof (arelent *);
2085 o->orelocation = bfd_alloc (abfd, amt);
2086 if (!o->orelocation)
2087 return FALSE;
2088 o->flags |= SEC_RELOC;
2089 /* Reset the count so that it can be used as an index
2090 when putting in the output relocs. */
2091 o->reloc_count = 0;
2096 /* Handle all the link order information for the sections. */
2097 for (o = abfd->sections; o != NULL; o = o->next)
2099 for (p = o->map_head.link_order; p != NULL; p = p->next)
2101 switch (p->type)
2103 case bfd_section_reloc_link_order:
2104 case bfd_symbol_reloc_link_order:
2105 if (! _bfd_generic_reloc_link_order (abfd, info, o, p))
2106 return FALSE;
2107 break;
2108 case bfd_indirect_link_order:
2109 if (! default_indirect_link_order (abfd, info, o, p, TRUE))
2110 return FALSE;
2111 break;
2112 default:
2113 if (! _bfd_default_link_order (abfd, info, o, p))
2114 return FALSE;
2115 break;
2120 return TRUE;
2123 /* Add an output symbol to the output BFD. */
2125 static bfd_boolean
2126 generic_add_output_symbol (bfd *output_bfd, size_t *psymalloc, asymbol *sym)
2128 if (bfd_get_symcount (output_bfd) >= *psymalloc)
2130 asymbol **newsyms;
2131 bfd_size_type amt;
2133 if (*psymalloc == 0)
2134 *psymalloc = 124;
2135 else
2136 *psymalloc *= 2;
2137 amt = *psymalloc;
2138 amt *= sizeof (asymbol *);
2139 newsyms = bfd_realloc (bfd_get_outsymbols (output_bfd), amt);
2140 if (newsyms == NULL)
2141 return FALSE;
2142 bfd_get_outsymbols (output_bfd) = newsyms;
2145 bfd_get_outsymbols (output_bfd) [bfd_get_symcount (output_bfd)] = sym;
2146 if (sym != NULL)
2147 ++ bfd_get_symcount (output_bfd);
2149 return TRUE;
2152 /* Handle the symbols for an input BFD. */
2154 bfd_boolean
2155 _bfd_generic_link_output_symbols (bfd *output_bfd,
2156 bfd *input_bfd,
2157 struct bfd_link_info *info,
2158 size_t *psymalloc)
2160 asymbol **sym_ptr;
2161 asymbol **sym_end;
2163 if (! generic_link_read_symbols (input_bfd))
2164 return FALSE;
2166 /* Create a filename symbol if we are supposed to. */
2167 if (info->create_object_symbols_section != NULL)
2169 asection *sec;
2171 for (sec = input_bfd->sections; sec != NULL; sec = sec->next)
2173 if (sec->output_section == info->create_object_symbols_section)
2175 asymbol *newsym;
2177 newsym = bfd_make_empty_symbol (input_bfd);
2178 if (!newsym)
2179 return FALSE;
2180 newsym->name = input_bfd->filename;
2181 newsym->value = 0;
2182 newsym->flags = BSF_LOCAL | BSF_FILE;
2183 newsym->section = sec;
2185 if (! generic_add_output_symbol (output_bfd, psymalloc,
2186 newsym))
2187 return FALSE;
2189 break;
2194 /* Adjust the values of the globally visible symbols, and write out
2195 local symbols. */
2196 sym_ptr = _bfd_generic_link_get_symbols (input_bfd);
2197 sym_end = sym_ptr + _bfd_generic_link_get_symcount (input_bfd);
2198 for (; sym_ptr < sym_end; sym_ptr++)
2200 asymbol *sym;
2201 struct generic_link_hash_entry *h;
2202 bfd_boolean output;
2204 h = NULL;
2205 sym = *sym_ptr;
2206 if ((sym->flags & (BSF_INDIRECT
2207 | BSF_WARNING
2208 | BSF_GLOBAL
2209 | BSF_CONSTRUCTOR
2210 | BSF_WEAK)) != 0
2211 || bfd_is_und_section (bfd_get_section (sym))
2212 || bfd_is_com_section (bfd_get_section (sym))
2213 || bfd_is_ind_section (bfd_get_section (sym)))
2215 if (sym->udata.p != NULL)
2216 h = sym->udata.p;
2217 else if ((sym->flags & BSF_CONSTRUCTOR) != 0)
2219 /* This case normally means that the main linker code
2220 deliberately ignored this constructor symbol. We
2221 should just pass it through. This will screw up if
2222 the constructor symbol is from a different,
2223 non-generic, object file format, but the case will
2224 only arise when linking with -r, which will probably
2225 fail anyhow, since there will be no way to represent
2226 the relocs in the output format being used. */
2227 h = NULL;
2229 else if (bfd_is_und_section (bfd_get_section (sym)))
2230 h = ((struct generic_link_hash_entry *)
2231 bfd_wrapped_link_hash_lookup (output_bfd, info,
2232 bfd_asymbol_name (sym),
2233 FALSE, FALSE, TRUE));
2234 else
2235 h = _bfd_generic_link_hash_lookup (_bfd_generic_hash_table (info),
2236 bfd_asymbol_name (sym),
2237 FALSE, FALSE, TRUE);
2239 if (h != NULL)
2241 /* Force all references to this symbol to point to
2242 the same area in memory. It is possible that
2243 this routine will be called with a hash table
2244 other than a generic hash table, so we double
2245 check that. */
2246 if (info->hash->creator == input_bfd->xvec)
2248 if (h->sym != NULL)
2249 *sym_ptr = sym = h->sym;
2252 switch (h->root.type)
2254 default:
2255 case bfd_link_hash_new:
2256 abort ();
2257 case bfd_link_hash_undefined:
2258 break;
2259 case bfd_link_hash_undefweak:
2260 sym->flags |= BSF_WEAK;
2261 break;
2262 case bfd_link_hash_indirect:
2263 h = (struct generic_link_hash_entry *) h->root.u.i.link;
2264 /* fall through */
2265 case bfd_link_hash_defined:
2266 sym->flags |= BSF_GLOBAL;
2267 sym->flags &=~ BSF_CONSTRUCTOR;
2268 sym->value = h->root.u.def.value;
2269 sym->section = h->root.u.def.section;
2270 break;
2271 case bfd_link_hash_defweak:
2272 sym->flags |= BSF_WEAK;
2273 sym->flags &=~ BSF_CONSTRUCTOR;
2274 sym->value = h->root.u.def.value;
2275 sym->section = h->root.u.def.section;
2276 break;
2277 case bfd_link_hash_common:
2278 sym->value = h->root.u.c.size;
2279 sym->flags |= BSF_GLOBAL;
2280 if (! bfd_is_com_section (sym->section))
2282 BFD_ASSERT (bfd_is_und_section (sym->section));
2283 sym->section = bfd_com_section_ptr;
2285 /* We do not set the section of the symbol to
2286 h->root.u.c.p->section. That value was saved so
2287 that we would know where to allocate the symbol
2288 if it was defined. In this case the type is
2289 still bfd_link_hash_common, so we did not define
2290 it, so we do not want to use that section. */
2291 break;
2296 /* This switch is straight from the old code in
2297 write_file_locals in ldsym.c. */
2298 if (info->strip == strip_all
2299 || (info->strip == strip_some
2300 && bfd_hash_lookup (info->keep_hash, bfd_asymbol_name (sym),
2301 FALSE, FALSE) == NULL))
2302 output = FALSE;
2303 else if ((sym->flags & (BSF_GLOBAL | BSF_WEAK)) != 0)
2305 /* If this symbol is marked as occurring now, rather
2306 than at the end, output it now. This is used for
2307 COFF C_EXT FCN symbols. FIXME: There must be a
2308 better way. */
2309 if (bfd_asymbol_bfd (sym) == input_bfd
2310 && (sym->flags & BSF_NOT_AT_END) != 0)
2311 output = TRUE;
2312 else
2313 output = FALSE;
2315 else if (bfd_is_ind_section (sym->section))
2316 output = FALSE;
2317 else if ((sym->flags & BSF_DEBUGGING) != 0)
2319 if (info->strip == strip_none)
2320 output = TRUE;
2321 else
2322 output = FALSE;
2324 else if (bfd_is_und_section (sym->section)
2325 || bfd_is_com_section (sym->section))
2326 output = FALSE;
2327 else if ((sym->flags & BSF_LOCAL) != 0)
2329 if ((sym->flags & BSF_WARNING) != 0)
2330 output = FALSE;
2331 else
2333 switch (info->discard)
2335 default:
2336 case discard_all:
2337 output = FALSE;
2338 break;
2339 case discard_sec_merge:
2340 output = TRUE;
2341 if (info->relocatable
2342 || ! (sym->section->flags & SEC_MERGE))
2343 break;
2344 /* FALLTHROUGH */
2345 case discard_l:
2346 if (bfd_is_local_label (input_bfd, sym))
2347 output = FALSE;
2348 else
2349 output = TRUE;
2350 break;
2351 case discard_none:
2352 output = TRUE;
2353 break;
2357 else if ((sym->flags & BSF_CONSTRUCTOR))
2359 if (info->strip != strip_all)
2360 output = TRUE;
2361 else
2362 output = FALSE;
2364 else
2365 abort ();
2367 /* If this symbol is in a section which is not being included
2368 in the output file, then we don't want to output the
2369 symbol. */
2370 if (!bfd_is_abs_section (sym->section)
2371 && bfd_section_removed_from_list (output_bfd,
2372 sym->section->output_section))
2373 output = FALSE;
2375 if (output)
2377 if (! generic_add_output_symbol (output_bfd, psymalloc, sym))
2378 return FALSE;
2379 if (h != NULL)
2380 h->written = TRUE;
2384 return TRUE;
2387 /* Set the section and value of a generic BFD symbol based on a linker
2388 hash table entry. */
2390 static void
2391 set_symbol_from_hash (asymbol *sym, struct bfd_link_hash_entry *h)
2393 switch (h->type)
2395 default:
2396 abort ();
2397 break;
2398 case bfd_link_hash_new:
2399 /* This can happen when a constructor symbol is seen but we are
2400 not building constructors. */
2401 if (sym->section != NULL)
2403 BFD_ASSERT ((sym->flags & BSF_CONSTRUCTOR) != 0);
2405 else
2407 sym->flags |= BSF_CONSTRUCTOR;
2408 sym->section = bfd_abs_section_ptr;
2409 sym->value = 0;
2411 break;
2412 case bfd_link_hash_undefined:
2413 sym->section = bfd_und_section_ptr;
2414 sym->value = 0;
2415 break;
2416 case bfd_link_hash_undefweak:
2417 sym->section = bfd_und_section_ptr;
2418 sym->value = 0;
2419 sym->flags |= BSF_WEAK;
2420 break;
2421 case bfd_link_hash_defined:
2422 sym->section = h->u.def.section;
2423 sym->value = h->u.def.value;
2424 break;
2425 case bfd_link_hash_defweak:
2426 sym->flags |= BSF_WEAK;
2427 sym->section = h->u.def.section;
2428 sym->value = h->u.def.value;
2429 break;
2430 case bfd_link_hash_common:
2431 sym->value = h->u.c.size;
2432 if (sym->section == NULL)
2433 sym->section = bfd_com_section_ptr;
2434 else if (! bfd_is_com_section (sym->section))
2436 BFD_ASSERT (bfd_is_und_section (sym->section));
2437 sym->section = bfd_com_section_ptr;
2439 /* Do not set the section; see _bfd_generic_link_output_symbols. */
2440 break;
2441 case bfd_link_hash_indirect:
2442 case bfd_link_hash_warning:
2443 /* FIXME: What should we do here? */
2444 break;
2448 /* Write out a global symbol, if it hasn't already been written out.
2449 This is called for each symbol in the hash table. */
2451 bfd_boolean
2452 _bfd_generic_link_write_global_symbol (struct generic_link_hash_entry *h,
2453 void *data)
2455 struct generic_write_global_symbol_info *wginfo = data;
2456 asymbol *sym;
2458 if (h->root.type == bfd_link_hash_warning)
2459 h = (struct generic_link_hash_entry *) h->root.u.i.link;
2461 if (h->written)
2462 return TRUE;
2464 h->written = TRUE;
2466 if (wginfo->info->strip == strip_all
2467 || (wginfo->info->strip == strip_some
2468 && bfd_hash_lookup (wginfo->info->keep_hash, h->root.root.string,
2469 FALSE, FALSE) == NULL))
2470 return TRUE;
2472 if (h->sym != NULL)
2473 sym = h->sym;
2474 else
2476 sym = bfd_make_empty_symbol (wginfo->output_bfd);
2477 if (!sym)
2478 return FALSE;
2479 sym->name = h->root.root.string;
2480 sym->flags = 0;
2483 set_symbol_from_hash (sym, &h->root);
2485 sym->flags |= BSF_GLOBAL;
2487 if (! generic_add_output_symbol (wginfo->output_bfd, wginfo->psymalloc,
2488 sym))
2490 /* FIXME: No way to return failure. */
2491 abort ();
2494 return TRUE;
2497 /* Create a relocation. */
2499 bfd_boolean
2500 _bfd_generic_reloc_link_order (bfd *abfd,
2501 struct bfd_link_info *info,
2502 asection *sec,
2503 struct bfd_link_order *link_order)
2505 arelent *r;
2507 if (! info->relocatable)
2508 abort ();
2509 if (sec->orelocation == NULL)
2510 abort ();
2512 r = bfd_alloc (abfd, sizeof (arelent));
2513 if (r == NULL)
2514 return FALSE;
2516 r->address = link_order->offset;
2517 r->howto = bfd_reloc_type_lookup (abfd, link_order->u.reloc.p->reloc);
2518 if (r->howto == 0)
2520 bfd_set_error (bfd_error_bad_value);
2521 return FALSE;
2524 /* Get the symbol to use for the relocation. */
2525 if (link_order->type == bfd_section_reloc_link_order)
2526 r->sym_ptr_ptr = link_order->u.reloc.p->u.section->symbol_ptr_ptr;
2527 else
2529 struct generic_link_hash_entry *h;
2531 h = ((struct generic_link_hash_entry *)
2532 bfd_wrapped_link_hash_lookup (abfd, info,
2533 link_order->u.reloc.p->u.name,
2534 FALSE, FALSE, TRUE));
2535 if (h == NULL
2536 || ! h->written)
2538 if (! ((*info->callbacks->unattached_reloc)
2539 (info, link_order->u.reloc.p->u.name, NULL, NULL, 0)))
2540 return FALSE;
2541 bfd_set_error (bfd_error_bad_value);
2542 return FALSE;
2544 r->sym_ptr_ptr = &h->sym;
2547 /* If this is an inplace reloc, write the addend to the object file.
2548 Otherwise, store it in the reloc addend. */
2549 if (! r->howto->partial_inplace)
2550 r->addend = link_order->u.reloc.p->addend;
2551 else
2553 bfd_size_type size;
2554 bfd_reloc_status_type rstat;
2555 bfd_byte *buf;
2556 bfd_boolean ok;
2557 file_ptr loc;
2559 size = bfd_get_reloc_size (r->howto);
2560 buf = bfd_zmalloc (size);
2561 if (buf == NULL)
2562 return FALSE;
2563 rstat = _bfd_relocate_contents (r->howto, abfd,
2564 (bfd_vma) link_order->u.reloc.p->addend,
2565 buf);
2566 switch (rstat)
2568 case bfd_reloc_ok:
2569 break;
2570 default:
2571 case bfd_reloc_outofrange:
2572 abort ();
2573 case bfd_reloc_overflow:
2574 if (! ((*info->callbacks->reloc_overflow)
2575 (info, NULL,
2576 (link_order->type == bfd_section_reloc_link_order
2577 ? bfd_section_name (abfd, link_order->u.reloc.p->u.section)
2578 : link_order->u.reloc.p->u.name),
2579 r->howto->name, link_order->u.reloc.p->addend,
2580 NULL, NULL, 0)))
2582 free (buf);
2583 return FALSE;
2585 break;
2587 loc = link_order->offset * bfd_octets_per_byte (abfd);
2588 ok = bfd_set_section_contents (abfd, sec, buf, loc, size);
2589 free (buf);
2590 if (! ok)
2591 return FALSE;
2593 r->addend = 0;
2596 sec->orelocation[sec->reloc_count] = r;
2597 ++sec->reloc_count;
2599 return TRUE;
2602 /* Allocate a new link_order for a section. */
2604 struct bfd_link_order *
2605 bfd_new_link_order (bfd *abfd, asection *section)
2607 bfd_size_type amt = sizeof (struct bfd_link_order);
2608 struct bfd_link_order *new;
2610 new = bfd_zalloc (abfd, amt);
2611 if (!new)
2612 return NULL;
2614 new->type = bfd_undefined_link_order;
2616 if (section->map_tail.link_order != NULL)
2617 section->map_tail.link_order->next = new;
2618 else
2619 section->map_head.link_order = new;
2620 section->map_tail.link_order = new;
2622 return new;
2625 /* Default link order processing routine. Note that we can not handle
2626 the reloc_link_order types here, since they depend upon the details
2627 of how the particular backends generates relocs. */
2629 bfd_boolean
2630 _bfd_default_link_order (bfd *abfd,
2631 struct bfd_link_info *info,
2632 asection *sec,
2633 struct bfd_link_order *link_order)
2635 switch (link_order->type)
2637 case bfd_undefined_link_order:
2638 case bfd_section_reloc_link_order:
2639 case bfd_symbol_reloc_link_order:
2640 default:
2641 abort ();
2642 case bfd_indirect_link_order:
2643 return default_indirect_link_order (abfd, info, sec, link_order,
2644 FALSE);
2645 case bfd_data_link_order:
2646 return default_data_link_order (abfd, info, sec, link_order);
2650 /* Default routine to handle a bfd_data_link_order. */
2652 static bfd_boolean
2653 default_data_link_order (bfd *abfd,
2654 struct bfd_link_info *info ATTRIBUTE_UNUSED,
2655 asection *sec,
2656 struct bfd_link_order *link_order)
2658 bfd_size_type size;
2659 size_t fill_size;
2660 bfd_byte *fill;
2661 file_ptr loc;
2662 bfd_boolean result;
2664 BFD_ASSERT ((sec->flags & SEC_HAS_CONTENTS) != 0);
2666 size = link_order->size;
2667 if (size == 0)
2668 return TRUE;
2670 fill = link_order->u.data.contents;
2671 fill_size = link_order->u.data.size;
2672 if (fill_size != 0 && fill_size < size)
2674 bfd_byte *p;
2675 fill = bfd_malloc (size);
2676 if (fill == NULL)
2677 return FALSE;
2678 p = fill;
2679 if (fill_size == 1)
2680 memset (p, (int) link_order->u.data.contents[0], (size_t) size);
2681 else
2685 memcpy (p, link_order->u.data.contents, fill_size);
2686 p += fill_size;
2687 size -= fill_size;
2689 while (size >= fill_size);
2690 if (size != 0)
2691 memcpy (p, link_order->u.data.contents, (size_t) size);
2692 size = link_order->size;
2696 loc = link_order->offset * bfd_octets_per_byte (abfd);
2697 result = bfd_set_section_contents (abfd, sec, fill, loc, size);
2699 if (fill != link_order->u.data.contents)
2700 free (fill);
2701 return result;
2704 /* Default routine to handle a bfd_indirect_link_order. */
2706 static bfd_boolean
2707 default_indirect_link_order (bfd *output_bfd,
2708 struct bfd_link_info *info,
2709 asection *output_section,
2710 struct bfd_link_order *link_order,
2711 bfd_boolean generic_linker)
2713 asection *input_section;
2714 bfd *input_bfd;
2715 bfd_byte *contents = NULL;
2716 bfd_byte *new_contents;
2717 bfd_size_type sec_size;
2718 file_ptr loc;
2720 BFD_ASSERT ((output_section->flags & SEC_HAS_CONTENTS) != 0);
2722 input_section = link_order->u.indirect.section;
2723 input_bfd = input_section->owner;
2724 if (input_section->size == 0)
2725 return TRUE;
2727 BFD_ASSERT (input_section->output_section == output_section);
2728 BFD_ASSERT (input_section->output_offset == link_order->offset);
2729 BFD_ASSERT (input_section->size == link_order->size);
2731 if (info->relocatable
2732 && input_section->reloc_count > 0
2733 && output_section->orelocation == NULL)
2735 /* Space has not been allocated for the output relocations.
2736 This can happen when we are called by a specific backend
2737 because somebody is attempting to link together different
2738 types of object files. Handling this case correctly is
2739 difficult, and sometimes impossible. */
2740 (*_bfd_error_handler)
2741 (_("Attempt to do relocatable link with %s input and %s output"),
2742 bfd_get_target (input_bfd), bfd_get_target (output_bfd));
2743 bfd_set_error (bfd_error_wrong_format);
2744 return FALSE;
2747 if (! generic_linker)
2749 asymbol **sympp;
2750 asymbol **symppend;
2752 /* Get the canonical symbols. The generic linker will always
2753 have retrieved them by this point, but we are being called by
2754 a specific linker, presumably because we are linking
2755 different types of object files together. */
2756 if (! generic_link_read_symbols (input_bfd))
2757 return FALSE;
2759 /* Since we have been called by a specific linker, rather than
2760 the generic linker, the values of the symbols will not be
2761 right. They will be the values as seen in the input file,
2762 not the values of the final link. We need to fix them up
2763 before we can relocate the section. */
2764 sympp = _bfd_generic_link_get_symbols (input_bfd);
2765 symppend = sympp + _bfd_generic_link_get_symcount (input_bfd);
2766 for (; sympp < symppend; sympp++)
2768 asymbol *sym;
2769 struct bfd_link_hash_entry *h;
2771 sym = *sympp;
2773 if ((sym->flags & (BSF_INDIRECT
2774 | BSF_WARNING
2775 | BSF_GLOBAL
2776 | BSF_CONSTRUCTOR
2777 | BSF_WEAK)) != 0
2778 || bfd_is_und_section (bfd_get_section (sym))
2779 || bfd_is_com_section (bfd_get_section (sym))
2780 || bfd_is_ind_section (bfd_get_section (sym)))
2782 /* sym->udata may have been set by
2783 generic_link_add_symbol_list. */
2784 if (sym->udata.p != NULL)
2785 h = sym->udata.p;
2786 else if (bfd_is_und_section (bfd_get_section (sym)))
2787 h = bfd_wrapped_link_hash_lookup (output_bfd, info,
2788 bfd_asymbol_name (sym),
2789 FALSE, FALSE, TRUE);
2790 else
2791 h = bfd_link_hash_lookup (info->hash,
2792 bfd_asymbol_name (sym),
2793 FALSE, FALSE, TRUE);
2794 if (h != NULL)
2795 set_symbol_from_hash (sym, h);
2800 /* Get and relocate the section contents. */
2801 sec_size = (input_section->rawsize > input_section->size
2802 ? input_section->rawsize
2803 : input_section->size);
2804 contents = bfd_malloc (sec_size);
2805 if (contents == NULL && sec_size != 0)
2806 goto error_return;
2807 new_contents = (bfd_get_relocated_section_contents
2808 (output_bfd, info, link_order, contents, info->relocatable,
2809 _bfd_generic_link_get_symbols (input_bfd)));
2810 if (!new_contents)
2811 goto error_return;
2813 /* Output the section contents. */
2814 loc = input_section->output_offset * bfd_octets_per_byte (output_bfd);
2815 if (! bfd_set_section_contents (output_bfd, output_section,
2816 new_contents, loc, input_section->size))
2817 goto error_return;
2819 if (contents != NULL)
2820 free (contents);
2821 return TRUE;
2823 error_return:
2824 if (contents != NULL)
2825 free (contents);
2826 return FALSE;
2829 /* A little routine to count the number of relocs in a link_order
2830 list. */
2832 unsigned int
2833 _bfd_count_link_order_relocs (struct bfd_link_order *link_order)
2835 register unsigned int c;
2836 register struct bfd_link_order *l;
2838 c = 0;
2839 for (l = link_order; l != NULL; l = l->next)
2841 if (l->type == bfd_section_reloc_link_order
2842 || l->type == bfd_symbol_reloc_link_order)
2843 ++c;
2846 return c;
2850 FUNCTION
2851 bfd_link_split_section
2853 SYNOPSIS
2854 bfd_boolean bfd_link_split_section (bfd *abfd, asection *sec);
2856 DESCRIPTION
2857 Return nonzero if @var{sec} should be split during a
2858 reloceatable or final link.
2860 .#define bfd_link_split_section(abfd, sec) \
2861 . BFD_SEND (abfd, _bfd_link_split_section, (abfd, sec))
2866 bfd_boolean
2867 _bfd_generic_link_split_section (bfd *abfd ATTRIBUTE_UNUSED,
2868 asection *sec ATTRIBUTE_UNUSED)
2870 return FALSE;
2874 FUNCTION
2875 bfd_section_already_linked
2877 SYNOPSIS
2878 void bfd_section_already_linked (bfd *abfd, asection *sec,
2879 struct bfd_link_info *info);
2881 DESCRIPTION
2882 Check if @var{sec} has been already linked during a reloceatable
2883 or final link.
2885 .#define bfd_section_already_linked(abfd, sec, info) \
2886 . BFD_SEND (abfd, _section_already_linked, (abfd, sec, info))
2891 /* Sections marked with the SEC_LINK_ONCE flag should only be linked
2892 once into the output. This routine checks each section, and
2893 arrange to discard it if a section of the same name has already
2894 been linked. This code assumes that all relevant sections have the
2895 SEC_LINK_ONCE flag set; that is, it does not depend solely upon the
2896 section name. bfd_section_already_linked is called via
2897 bfd_map_over_sections. */
2899 /* The hash table. */
2901 static struct bfd_hash_table _bfd_section_already_linked_table;
2903 /* Support routines for the hash table used by section_already_linked,
2904 initialize the table, traverse, lookup, fill in an entry and remove
2905 the table. */
2907 void
2908 bfd_section_already_linked_table_traverse
2909 (bfd_boolean (*func) (struct bfd_section_already_linked_hash_entry *,
2910 void *), void *info)
2912 bfd_hash_traverse (&_bfd_section_already_linked_table,
2913 (bfd_boolean (*) (struct bfd_hash_entry *,
2914 void *)) func,
2915 info);
2918 struct bfd_section_already_linked_hash_entry *
2919 bfd_section_already_linked_table_lookup (const char *name)
2921 return ((struct bfd_section_already_linked_hash_entry *)
2922 bfd_hash_lookup (&_bfd_section_already_linked_table, name,
2923 TRUE, FALSE));
2926 bfd_boolean
2927 bfd_section_already_linked_table_insert
2928 (struct bfd_section_already_linked_hash_entry *already_linked_list,
2929 asection *sec)
2931 struct bfd_section_already_linked *l;
2933 /* Allocate the memory from the same obstack as the hash table is
2934 kept in. */
2935 l = bfd_hash_allocate (&_bfd_section_already_linked_table, sizeof *l);
2936 if (l == NULL)
2937 return FALSE;
2938 l->sec = sec;
2939 l->next = already_linked_list->entry;
2940 already_linked_list->entry = l;
2941 return TRUE;
2944 static struct bfd_hash_entry *
2945 already_linked_newfunc (struct bfd_hash_entry *entry ATTRIBUTE_UNUSED,
2946 struct bfd_hash_table *table,
2947 const char *string ATTRIBUTE_UNUSED)
2949 struct bfd_section_already_linked_hash_entry *ret =
2950 bfd_hash_allocate (table, sizeof *ret);
2952 if (ret == NULL)
2953 return NULL;
2955 ret->entry = NULL;
2957 return &ret->root;
2960 bfd_boolean
2961 bfd_section_already_linked_table_init (void)
2963 return bfd_hash_table_init_n (&_bfd_section_already_linked_table,
2964 already_linked_newfunc,
2965 sizeof (struct bfd_section_already_linked_hash_entry),
2966 42);
2969 void
2970 bfd_section_already_linked_table_free (void)
2972 bfd_hash_table_free (&_bfd_section_already_linked_table);
2975 /* This is used on non-ELF inputs. */
2977 void
2978 _bfd_generic_section_already_linked (bfd *abfd, asection *sec,
2979 struct bfd_link_info *info)
2981 flagword flags;
2982 const char *name;
2983 struct bfd_section_already_linked *l;
2984 struct bfd_section_already_linked_hash_entry *already_linked_list;
2986 flags = sec->flags;
2987 if ((flags & SEC_LINK_ONCE) == 0)
2988 return;
2990 /* FIXME: When doing a relocatable link, we may have trouble
2991 copying relocations in other sections that refer to local symbols
2992 in the section being discarded. Those relocations will have to
2993 be converted somehow; as of this writing I'm not sure that any of
2994 the backends handle that correctly.
2996 It is tempting to instead not discard link once sections when
2997 doing a relocatable link (technically, they should be discarded
2998 whenever we are building constructors). However, that fails,
2999 because the linker winds up combining all the link once sections
3000 into a single large link once section, which defeats the purpose
3001 of having link once sections in the first place. */
3003 name = bfd_get_section_name (abfd, sec);
3005 already_linked_list = bfd_section_already_linked_table_lookup (name);
3007 for (l = already_linked_list->entry; l != NULL; l = l->next)
3009 bfd_boolean skip = FALSE;
3010 struct coff_comdat_info *s_comdat
3011 = bfd_coff_get_comdat_section (abfd, sec);
3012 struct coff_comdat_info *l_comdat
3013 = bfd_coff_get_comdat_section (l->sec->owner, l->sec);
3015 /* We may have 3 different sections on the list: group section,
3016 comdat section and linkonce section. SEC may be a linkonce or
3017 comdat section. We always ignore group section. For non-COFF
3018 inputs, we also ignore comdat section.
3020 FIXME: Is that safe to match a linkonce section with a comdat
3021 section for COFF inputs? */
3022 if ((l->sec->flags & SEC_GROUP) != 0)
3023 skip = TRUE;
3024 else if (bfd_get_flavour (abfd) == bfd_target_coff_flavour)
3026 if (s_comdat != NULL
3027 && l_comdat != NULL
3028 && strcmp (s_comdat->name, l_comdat->name) != 0)
3029 skip = TRUE;
3031 else if (l_comdat != NULL)
3032 skip = TRUE;
3034 if (!skip)
3036 /* The section has already been linked. See if we should
3037 issue a warning. */
3038 switch (flags & SEC_LINK_DUPLICATES)
3040 default:
3041 abort ();
3043 case SEC_LINK_DUPLICATES_DISCARD:
3044 break;
3046 case SEC_LINK_DUPLICATES_ONE_ONLY:
3047 (*_bfd_error_handler)
3048 (_("%B: warning: ignoring duplicate section `%A'\n"),
3049 abfd, sec);
3050 break;
3052 case SEC_LINK_DUPLICATES_SAME_CONTENTS:
3053 /* FIXME: We should really dig out the contents of both
3054 sections and memcmp them. The COFF/PE spec says that
3055 the Microsoft linker does not implement this
3056 correctly, so I'm not going to bother doing it
3057 either. */
3058 /* Fall through. */
3059 case SEC_LINK_DUPLICATES_SAME_SIZE:
3060 if (sec->size != l->sec->size)
3061 (*_bfd_error_handler)
3062 (_("%B: warning: duplicate section `%A' has different size\n"),
3063 abfd, sec);
3064 break;
3067 /* Set the output_section field so that lang_add_section
3068 does not create a lang_input_section structure for this
3069 section. Since there might be a symbol in the section
3070 being discarded, we must retain a pointer to the section
3071 which we are really going to use. */
3072 sec->output_section = bfd_abs_section_ptr;
3073 sec->kept_section = l->sec;
3075 return;
3079 /* This is the first section with this name. Record it. */
3080 if (! bfd_section_already_linked_table_insert (already_linked_list, sec))
3081 info->callbacks->einfo (_("%F%P: already_linked_table: %E"));
3084 /* Convert symbols in excluded output sections to use a kept section. */
3086 static bfd_boolean
3087 fix_syms (struct bfd_link_hash_entry *h, void *data)
3089 bfd *obfd = (bfd *) data;
3091 if (h->type == bfd_link_hash_warning)
3092 h = h->u.i.link;
3094 if (h->type == bfd_link_hash_defined
3095 || h->type == bfd_link_hash_defweak)
3097 asection *s = h->u.def.section;
3098 if (s != NULL
3099 && s->output_section != NULL
3100 && (s->output_section->flags & SEC_EXCLUDE) != 0
3101 && bfd_section_removed_from_list (obfd, s->output_section))
3103 asection *op, *op1;
3105 h->u.def.value += s->output_offset + s->output_section->vma;
3107 /* Find preceding kept section. */
3108 for (op1 = s->output_section->prev; op1 != NULL; op1 = op1->prev)
3109 if ((op1->flags & SEC_EXCLUDE) == 0
3110 && !bfd_section_removed_from_list (obfd, op1))
3111 break;
3113 /* Find following kept section. Start at prev->next because
3114 other sections may have been added after S was removed. */
3115 if (s->output_section->prev != NULL)
3116 op = s->output_section->prev->next;
3117 else
3118 op = s->output_section->owner->sections;
3119 for (; op != NULL; op = op->next)
3120 if ((op->flags & SEC_EXCLUDE) == 0
3121 && !bfd_section_removed_from_list (obfd, op))
3122 break;
3124 /* Choose better of two sections, based on flags. The idea
3125 is to choose a section that will be in the same segment
3126 as S would have been if it was kept. */
3127 if (op1 == NULL)
3129 if (op == NULL)
3130 op = bfd_abs_section_ptr;
3132 else if (op == NULL)
3133 op = op1;
3134 else if (((op1->flags ^ op->flags)
3135 & (SEC_ALLOC | SEC_THREAD_LOCAL)) != 0)
3137 if (((op->flags ^ s->flags)
3138 & (SEC_ALLOC | SEC_THREAD_LOCAL)) != 0)
3139 op = op1;
3141 else if (((op1->flags ^ op->flags) & SEC_READONLY) != 0)
3143 if (((op->flags ^ s->flags) & SEC_READONLY) != 0)
3144 op = op1;
3146 else if (((op1->flags ^ op->flags) & SEC_CODE) != 0)
3148 if (((op->flags ^ s->flags) & SEC_CODE) != 0)
3149 op = op1;
3151 else
3153 /* Flags we care about are the same. Prefer the following
3154 section if that will result in a positive valued sym. */
3155 if (h->u.def.value < op->vma)
3156 op = op1;
3159 h->u.def.value -= op->vma;
3160 h->u.def.section = op;
3164 return TRUE;
3167 void
3168 _bfd_fix_excluded_sec_syms (bfd *obfd, struct bfd_link_info *info)
3170 bfd_link_hash_traverse (info->hash, fix_syms, obfd);