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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, 2008, 2009
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 output bfd
155 xvec must be checked to make sure that the hash table was
156 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 output bfd 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. (The
227 callback may in fact indicate that a replacement BFD should be
228 used, in which case the symbols from that BFD should be added
229 to the linker hash table instead.)
231 @findex _bfd_generic_link_add_archive_symbols
232 In most cases the work of looking through the symbols in the
233 archive should be done by the
234 <<_bfd_generic_link_add_archive_symbols>> function. This
235 function builds a hash table from the archive symbol table and
236 looks through the list of undefined symbols to see which
237 elements should be included.
238 <<_bfd_generic_link_add_archive_symbols>> is passed a function
239 to call to make the final decision about adding an archive
240 element to the link and to do the actual work of adding the
241 symbols to the linker hash table.
243 The function passed to
244 <<_bfd_generic_link_add_archive_symbols>> must read the
245 symbols of the archive element and decide whether the archive
246 element should be included in the link. If the element is to
247 be included, the <<add_archive_element>> linker callback
248 routine must be called with the element as an argument, and
249 the element's symbols must be added to the linker hash table
250 just as though the element had itself been passed to the
251 <<_bfd_link_add_symbols>> function. The <<add_archive_element>>
252 callback has the option to indicate that it would like to
253 replace the element archive with a substitute BFD, in which
254 case it is the symbols of that substitute BFD that must be
255 added to the linker hash table instead.
257 When the a.out <<_bfd_link_add_symbols>> function receives an
258 archive, it calls <<_bfd_generic_link_add_archive_symbols>>
259 passing <<aout_link_check_archive_element>> as the function
260 argument. <<aout_link_check_archive_element>> calls
261 <<aout_link_check_ar_symbols>>. If the latter decides to add
262 the element (an element is only added if it provides a real,
263 non-common, definition for a previously undefined or common
264 symbol) it calls the <<add_archive_element>> callback and then
265 <<aout_link_check_archive_element>> calls
266 <<aout_link_add_symbols>> to actually add the symbols to the
267 linker hash table - possibly those of a substitute BFD, if the
268 <<add_archive_element>> callback avails itself of that option.
270 The ECOFF back end is unusual in that it does not normally
271 call <<_bfd_generic_link_add_archive_symbols>>, because ECOFF
272 archives already contain a hash table of symbols. The ECOFF
273 back end searches the archive itself to avoid the overhead of
274 creating a new hash table.
276 INODE
277 Performing the Final Link, , Adding Symbols to the Hash Table, Linker Functions
278 SUBSECTION
279 Performing the final link
281 @cindex _bfd_link_final_link in target vector
282 @cindex target vector (_bfd_final_link)
283 When all the input files have been processed, the linker calls
284 the <<_bfd_final_link>> entry point of the output BFD. This
285 routine is responsible for producing the final output file,
286 which has several aspects. It must relocate the contents of
287 the input sections and copy the data into the output sections.
288 It must build an output symbol table including any local
289 symbols from the input files and the global symbols from the
290 hash table. When producing relocatable output, it must
291 modify the input relocs and write them into the output file.
292 There may also be object format dependent work to be done.
294 The linker will also call the <<write_object_contents>> entry
295 point when the BFD is closed. The two entry points must work
296 together in order to produce the correct output file.
298 The details of how this works are inevitably dependent upon
299 the specific object file format. The a.out
300 <<_bfd_final_link>> routine is <<NAME(aout,final_link)>>.
302 @menu
303 @* Information provided by the linker::
304 @* Relocating the section contents::
305 @* Writing the symbol table::
306 @end menu
308 INODE
309 Information provided by the linker, Relocating the section contents, Performing the Final Link, Performing the Final Link
310 SUBSUBSECTION
311 Information provided by the linker
313 Before the linker calls the <<_bfd_final_link>> entry point,
314 it sets up some data structures for the function to use.
316 The <<input_bfds>> field of the <<bfd_link_info>> structure
317 will point to a list of all the input files included in the
318 link. These files are linked through the <<link_next>> field
319 of the <<bfd>> structure.
321 Each section in the output file will have a list of
322 <<link_order>> structures attached to the <<map_head.link_order>>
323 field (the <<link_order>> structure is defined in
324 <<bfdlink.h>>). These structures describe how to create the
325 contents of the output section in terms of the contents of
326 various input sections, fill constants, and, eventually, other
327 types of information. They also describe relocs that must be
328 created by the BFD backend, but do not correspond to any input
329 file; this is used to support -Ur, which builds constructors
330 while generating a relocatable object file.
332 INODE
333 Relocating the section contents, Writing the symbol table, Information provided by the linker, Performing the Final Link
334 SUBSUBSECTION
335 Relocating the section contents
337 The <<_bfd_final_link>> function should look through the
338 <<link_order>> structures attached to each section of the
339 output file. Each <<link_order>> structure should either be
340 handled specially, or it should be passed to the function
341 <<_bfd_default_link_order>> which will do the right thing
342 (<<_bfd_default_link_order>> is defined in <<linker.c>>).
344 For efficiency, a <<link_order>> of type
345 <<bfd_indirect_link_order>> whose associated section belongs
346 to a BFD of the same format as the output BFD must be handled
347 specially. This type of <<link_order>> describes part of an
348 output section in terms of a section belonging to one of the
349 input files. The <<_bfd_final_link>> function should read the
350 contents of the section and any associated relocs, apply the
351 relocs to the section contents, and write out the modified
352 section contents. If performing a relocatable link, the
353 relocs themselves must also be modified and written out.
355 @findex _bfd_relocate_contents
356 @findex _bfd_final_link_relocate
357 The functions <<_bfd_relocate_contents>> and
358 <<_bfd_final_link_relocate>> provide some general support for
359 performing the actual relocations, notably overflow checking.
360 Their arguments include information about the symbol the
361 relocation is against and a <<reloc_howto_type>> argument
362 which describes the relocation to perform. These functions
363 are defined in <<reloc.c>>.
365 The a.out function which handles reading, relocating, and
366 writing section contents is <<aout_link_input_section>>. The
367 actual relocation is done in <<aout_link_input_section_std>>
368 and <<aout_link_input_section_ext>>.
370 INODE
371 Writing the symbol table, , Relocating the section contents, Performing the Final Link
372 SUBSUBSECTION
373 Writing the symbol table
375 The <<_bfd_final_link>> function must gather all the symbols
376 in the input files and write them out. It must also write out
377 all the symbols in the global hash table. This must be
378 controlled by the <<strip>> and <<discard>> fields of the
379 <<bfd_link_info>> structure.
381 The local symbols of the input files will not have been
382 entered into the linker hash table. The <<_bfd_final_link>>
383 routine must consider each input file and include the symbols
384 in the output file. It may be convenient to do this when
385 looking through the <<link_order>> structures, or it may be
386 done by stepping through the <<input_bfds>> list.
388 The <<_bfd_final_link>> routine must also traverse the global
389 hash table to gather all the externally visible symbols. It
390 is possible that most of the externally visible symbols may be
391 written out when considering the symbols of each input file,
392 but it is still necessary to traverse the hash table since the
393 linker script may have defined some symbols that are not in
394 any of the input files.
396 The <<strip>> field of the <<bfd_link_info>> structure
397 controls which symbols are written out. The possible values
398 are listed in <<bfdlink.h>>. If the value is <<strip_some>>,
399 then the <<keep_hash>> field of the <<bfd_link_info>>
400 structure is a hash table of symbols to keep; each symbol
401 should be looked up in this hash table, and only symbols which
402 are present should be included in the output file.
404 If the <<strip>> field of the <<bfd_link_info>> structure
405 permits local symbols to be written out, the <<discard>> field
406 is used to further controls which local symbols are included
407 in the output file. If the value is <<discard_l>>, then all
408 local symbols which begin with a certain prefix are discarded;
409 this is controlled by the <<bfd_is_local_label_name>> entry point.
411 The a.out backend handles symbols by calling
412 <<aout_link_write_symbols>> on each input BFD and then
413 traversing the global hash table with the function
414 <<aout_link_write_other_symbol>>. It builds a string table
415 while writing out the symbols, which is written to the output
416 file at the end of <<NAME(aout,final_link)>>.
419 static bfd_boolean generic_link_add_object_symbols
420 (bfd *, struct bfd_link_info *, bfd_boolean collect);
421 static bfd_boolean generic_link_add_symbols
422 (bfd *, struct bfd_link_info *, bfd_boolean);
423 static bfd_boolean generic_link_check_archive_element_no_collect
424 (bfd *, struct bfd_link_info *, bfd_boolean *);
425 static bfd_boolean generic_link_check_archive_element_collect
426 (bfd *, struct bfd_link_info *, bfd_boolean *);
427 static bfd_boolean generic_link_check_archive_element
428 (bfd *, struct bfd_link_info *, bfd_boolean *, bfd_boolean);
429 static bfd_boolean generic_link_add_symbol_list
430 (bfd *, struct bfd_link_info *, bfd_size_type count, asymbol **,
431 bfd_boolean);
432 static bfd_boolean generic_add_output_symbol
433 (bfd *, size_t *psymalloc, asymbol *);
434 static bfd_boolean default_data_link_order
435 (bfd *, struct bfd_link_info *, asection *, struct bfd_link_order *);
436 static bfd_boolean default_indirect_link_order
437 (bfd *, struct bfd_link_info *, asection *, struct bfd_link_order *,
438 bfd_boolean);
440 /* The link hash table structure is defined in bfdlink.h. It provides
441 a base hash table which the backend specific hash tables are built
442 upon. */
444 /* Routine to create an entry in the link hash table. */
446 struct bfd_hash_entry *
447 _bfd_link_hash_newfunc (struct bfd_hash_entry *entry,
448 struct bfd_hash_table *table,
449 const char *string)
451 /* Allocate the structure if it has not already been allocated by a
452 subclass. */
453 if (entry == NULL)
455 entry = (struct bfd_hash_entry *)
456 bfd_hash_allocate (table, sizeof (struct bfd_link_hash_entry));
457 if (entry == NULL)
458 return entry;
461 /* Call the allocation method of the superclass. */
462 entry = bfd_hash_newfunc (entry, table, string);
463 if (entry)
465 struct bfd_link_hash_entry *h = (struct bfd_link_hash_entry *) entry;
467 /* Initialize the local fields. */
468 h->type = bfd_link_hash_new;
469 memset (&h->u.undef.next, 0,
470 (sizeof (struct bfd_link_hash_entry)
471 - offsetof (struct bfd_link_hash_entry, u.undef.next)));
474 return entry;
477 /* Initialize a link hash table. The BFD argument is the one
478 responsible for creating this table. */
480 bfd_boolean
481 _bfd_link_hash_table_init
482 (struct bfd_link_hash_table *table,
483 bfd *abfd ATTRIBUTE_UNUSED,
484 struct bfd_hash_entry *(*newfunc) (struct bfd_hash_entry *,
485 struct bfd_hash_table *,
486 const char *),
487 unsigned int entsize)
489 table->undefs = NULL;
490 table->undefs_tail = NULL;
491 table->type = bfd_link_generic_hash_table;
493 return bfd_hash_table_init (&table->table, newfunc, entsize);
496 /* Look up a symbol in a link hash table. If follow is TRUE, we
497 follow bfd_link_hash_indirect and bfd_link_hash_warning links to
498 the real symbol. */
500 struct bfd_link_hash_entry *
501 bfd_link_hash_lookup (struct bfd_link_hash_table *table,
502 const char *string,
503 bfd_boolean create,
504 bfd_boolean copy,
505 bfd_boolean follow)
507 struct bfd_link_hash_entry *ret;
509 ret = ((struct bfd_link_hash_entry *)
510 bfd_hash_lookup (&table->table, string, create, copy));
512 if (follow && ret != NULL)
514 while (ret->type == bfd_link_hash_indirect
515 || ret->type == bfd_link_hash_warning)
516 ret = ret->u.i.link;
519 return ret;
522 /* Look up a symbol in the main linker hash table if the symbol might
523 be wrapped. This should only be used for references to an
524 undefined symbol, not for definitions of a symbol. */
526 struct bfd_link_hash_entry *
527 bfd_wrapped_link_hash_lookup (bfd *abfd,
528 struct bfd_link_info *info,
529 const char *string,
530 bfd_boolean create,
531 bfd_boolean copy,
532 bfd_boolean follow)
534 bfd_size_type amt;
536 if (info->wrap_hash != NULL)
538 const char *l;
539 char prefix = '\0';
541 l = string;
542 if (*l == bfd_get_symbol_leading_char (abfd) || *l == info->wrap_char)
544 prefix = *l;
545 ++l;
548 #undef WRAP
549 #define WRAP "__wrap_"
551 if (bfd_hash_lookup (info->wrap_hash, l, FALSE, FALSE) != NULL)
553 char *n;
554 struct bfd_link_hash_entry *h;
556 /* This symbol is being wrapped. We want to replace all
557 references to SYM with references to __wrap_SYM. */
559 amt = strlen (l) + sizeof WRAP + 1;
560 n = (char *) bfd_malloc (amt);
561 if (n == NULL)
562 return NULL;
564 n[0] = prefix;
565 n[1] = '\0';
566 strcat (n, WRAP);
567 strcat (n, l);
568 h = bfd_link_hash_lookup (info->hash, n, create, TRUE, follow);
569 free (n);
570 return h;
573 #undef WRAP
575 #undef REAL
576 #define REAL "__real_"
578 if (*l == '_'
579 && CONST_STRNEQ (l, REAL)
580 && bfd_hash_lookup (info->wrap_hash, l + sizeof REAL - 1,
581 FALSE, FALSE) != NULL)
583 char *n;
584 struct bfd_link_hash_entry *h;
586 /* This is a reference to __real_SYM, where SYM is being
587 wrapped. We want to replace all references to __real_SYM
588 with references to SYM. */
590 amt = strlen (l + sizeof REAL - 1) + 2;
591 n = (char *) bfd_malloc (amt);
592 if (n == NULL)
593 return NULL;
595 n[0] = prefix;
596 n[1] = '\0';
597 strcat (n, l + sizeof REAL - 1);
598 h = bfd_link_hash_lookup (info->hash, n, create, TRUE, follow);
599 free (n);
600 return h;
603 #undef REAL
606 return bfd_link_hash_lookup (info->hash, string, create, copy, follow);
609 /* Traverse a generic link hash table. The only reason this is not a
610 macro is to do better type checking. This code presumes that an
611 argument passed as a struct bfd_hash_entry * may be caught as a
612 struct bfd_link_hash_entry * with no explicit cast required on the
613 call. */
615 void
616 bfd_link_hash_traverse
617 (struct bfd_link_hash_table *table,
618 bfd_boolean (*func) (struct bfd_link_hash_entry *, void *),
619 void *info)
621 bfd_hash_traverse (&table->table,
622 (bfd_boolean (*) (struct bfd_hash_entry *, void *)) func,
623 info);
626 /* Add a symbol to the linker hash table undefs list. */
628 void
629 bfd_link_add_undef (struct bfd_link_hash_table *table,
630 struct bfd_link_hash_entry *h)
632 BFD_ASSERT (h->u.undef.next == NULL);
633 if (table->undefs_tail != NULL)
634 table->undefs_tail->u.undef.next = h;
635 if (table->undefs == NULL)
636 table->undefs = h;
637 table->undefs_tail = h;
640 /* The undefs list was designed so that in normal use we don't need to
641 remove entries. However, if symbols on the list are changed from
642 bfd_link_hash_undefined to either bfd_link_hash_undefweak or
643 bfd_link_hash_new for some reason, then they must be removed from the
644 list. Failure to do so might result in the linker attempting to add
645 the symbol to the list again at a later stage. */
647 void
648 bfd_link_repair_undef_list (struct bfd_link_hash_table *table)
650 struct bfd_link_hash_entry **pun;
652 pun = &table->undefs;
653 while (*pun != NULL)
655 struct bfd_link_hash_entry *h = *pun;
657 if (h->type == bfd_link_hash_new
658 || h->type == bfd_link_hash_undefweak)
660 *pun = h->u.undef.next;
661 h->u.undef.next = NULL;
662 if (h == table->undefs_tail)
664 if (pun == &table->undefs)
665 table->undefs_tail = NULL;
666 else
667 /* pun points at an u.undef.next field. Go back to
668 the start of the link_hash_entry. */
669 table->undefs_tail = (struct bfd_link_hash_entry *)
670 ((char *) pun - ((char *) &h->u.undef.next - (char *) h));
671 break;
674 else
675 pun = &h->u.undef.next;
679 /* Routine to create an entry in a generic link hash table. */
681 struct bfd_hash_entry *
682 _bfd_generic_link_hash_newfunc (struct bfd_hash_entry *entry,
683 struct bfd_hash_table *table,
684 const char *string)
686 /* Allocate the structure if it has not already been allocated by a
687 subclass. */
688 if (entry == NULL)
690 entry = (struct bfd_hash_entry *)
691 bfd_hash_allocate (table, sizeof (struct generic_link_hash_entry));
692 if (entry == NULL)
693 return entry;
696 /* Call the allocation method of the superclass. */
697 entry = _bfd_link_hash_newfunc (entry, table, string);
698 if (entry)
700 struct generic_link_hash_entry *ret;
702 /* Set local fields. */
703 ret = (struct generic_link_hash_entry *) entry;
704 ret->written = FALSE;
705 ret->sym = NULL;
708 return entry;
711 /* Create a generic link hash table. */
713 struct bfd_link_hash_table *
714 _bfd_generic_link_hash_table_create (bfd *abfd)
716 struct generic_link_hash_table *ret;
717 bfd_size_type amt = sizeof (struct generic_link_hash_table);
719 ret = (struct generic_link_hash_table *) bfd_malloc (amt);
720 if (ret == NULL)
721 return NULL;
722 if (! _bfd_link_hash_table_init (&ret->root, abfd,
723 _bfd_generic_link_hash_newfunc,
724 sizeof (struct generic_link_hash_entry)))
726 free (ret);
727 return NULL;
729 return &ret->root;
732 void
733 _bfd_generic_link_hash_table_free (struct bfd_link_hash_table *hash)
735 struct generic_link_hash_table *ret
736 = (struct generic_link_hash_table *) hash;
738 bfd_hash_table_free (&ret->root.table);
739 free (ret);
742 /* Grab the symbols for an object file when doing a generic link. We
743 store the symbols in the outsymbols field. We need to keep them
744 around for the entire link to ensure that we only read them once.
745 If we read them multiple times, we might wind up with relocs and
746 the hash table pointing to different instances of the symbol
747 structure. */
749 bfd_boolean
750 bfd_generic_link_read_symbols (bfd *abfd)
752 if (bfd_get_outsymbols (abfd) == NULL)
754 long symsize;
755 long symcount;
757 symsize = bfd_get_symtab_upper_bound (abfd);
758 if (symsize < 0)
759 return FALSE;
760 bfd_get_outsymbols (abfd) = (struct bfd_symbol **) bfd_alloc (abfd,
761 symsize);
762 if (bfd_get_outsymbols (abfd) == NULL && symsize != 0)
763 return FALSE;
764 symcount = bfd_canonicalize_symtab (abfd, bfd_get_outsymbols (abfd));
765 if (symcount < 0)
766 return FALSE;
767 bfd_get_symcount (abfd) = symcount;
770 return TRUE;
773 /* Generic function to add symbols to from an object file to the
774 global hash table. This version does not automatically collect
775 constructors by name. */
777 bfd_boolean
778 _bfd_generic_link_add_symbols (bfd *abfd, struct bfd_link_info *info)
780 return generic_link_add_symbols (abfd, info, FALSE);
783 /* Generic function to add symbols from an object file to the global
784 hash table. This version automatically collects constructors by
785 name, as the collect2 program does. It should be used for any
786 target which does not provide some other mechanism for setting up
787 constructors and destructors; these are approximately those targets
788 for which gcc uses collect2 and do not support stabs. */
790 bfd_boolean
791 _bfd_generic_link_add_symbols_collect (bfd *abfd, struct bfd_link_info *info)
793 return generic_link_add_symbols (abfd, info, TRUE);
796 /* Indicate that we are only retrieving symbol values from this
797 section. We want the symbols to act as though the values in the
798 file are absolute. */
800 void
801 _bfd_generic_link_just_syms (asection *sec,
802 struct bfd_link_info *info ATTRIBUTE_UNUSED)
804 sec->output_section = bfd_abs_section_ptr;
805 sec->output_offset = sec->vma;
808 /* Copy the type of a symbol assiciated with a linker hast table entry.
809 Override this so that symbols created in linker scripts get their
810 type from the RHS of the assignment.
811 The default implementation does nothing. */
812 void
813 _bfd_generic_copy_link_hash_symbol_type (bfd *abfd ATTRIBUTE_UNUSED,
814 struct bfd_link_hash_entry * hdest ATTRIBUTE_UNUSED,
815 struct bfd_link_hash_entry * hsrc ATTRIBUTE_UNUSED)
819 /* Add symbols from an object file to the global hash table. */
821 static bfd_boolean
822 generic_link_add_symbols (bfd *abfd,
823 struct bfd_link_info *info,
824 bfd_boolean collect)
826 bfd_boolean ret;
828 switch (bfd_get_format (abfd))
830 case bfd_object:
831 ret = generic_link_add_object_symbols (abfd, info, collect);
832 break;
833 case bfd_archive:
834 ret = (_bfd_generic_link_add_archive_symbols
835 (abfd, info,
836 (collect
837 ? generic_link_check_archive_element_collect
838 : generic_link_check_archive_element_no_collect)));
839 break;
840 default:
841 bfd_set_error (bfd_error_wrong_format);
842 ret = FALSE;
845 return ret;
848 /* Add symbols from an object file to the global hash table. */
850 static bfd_boolean
851 generic_link_add_object_symbols (bfd *abfd,
852 struct bfd_link_info *info,
853 bfd_boolean collect)
855 bfd_size_type symcount;
856 struct bfd_symbol **outsyms;
858 if (!bfd_generic_link_read_symbols (abfd))
859 return FALSE;
860 symcount = _bfd_generic_link_get_symcount (abfd);
861 outsyms = _bfd_generic_link_get_symbols (abfd);
862 return generic_link_add_symbol_list (abfd, info, symcount, outsyms, collect);
865 /* We build a hash table of all symbols defined in an archive. */
867 /* An archive symbol may be defined by multiple archive elements.
868 This linked list is used to hold the elements. */
870 struct archive_list
872 struct archive_list *next;
873 unsigned int indx;
876 /* An entry in an archive hash table. */
878 struct archive_hash_entry
880 struct bfd_hash_entry root;
881 /* Where the symbol is defined. */
882 struct archive_list *defs;
885 /* An archive hash table itself. */
887 struct archive_hash_table
889 struct bfd_hash_table table;
892 /* Create a new entry for an archive hash table. */
894 static struct bfd_hash_entry *
895 archive_hash_newfunc (struct bfd_hash_entry *entry,
896 struct bfd_hash_table *table,
897 const char *string)
899 struct archive_hash_entry *ret = (struct archive_hash_entry *) entry;
901 /* Allocate the structure if it has not already been allocated by a
902 subclass. */
903 if (ret == NULL)
904 ret = (struct archive_hash_entry *)
905 bfd_hash_allocate (table, sizeof (struct archive_hash_entry));
906 if (ret == NULL)
907 return NULL;
909 /* Call the allocation method of the superclass. */
910 ret = ((struct archive_hash_entry *)
911 bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));
913 if (ret)
915 /* Initialize the local fields. */
916 ret->defs = NULL;
919 return &ret->root;
922 /* Initialize an archive hash table. */
924 static bfd_boolean
925 archive_hash_table_init
926 (struct archive_hash_table *table,
927 struct bfd_hash_entry *(*newfunc) (struct bfd_hash_entry *,
928 struct bfd_hash_table *,
929 const char *),
930 unsigned int entsize)
932 return bfd_hash_table_init (&table->table, newfunc, entsize);
935 /* Look up an entry in an archive hash table. */
937 #define archive_hash_lookup(t, string, create, copy) \
938 ((struct archive_hash_entry *) \
939 bfd_hash_lookup (&(t)->table, (string), (create), (copy)))
941 /* Allocate space in an archive hash table. */
943 #define archive_hash_allocate(t, size) bfd_hash_allocate (&(t)->table, (size))
945 /* Free an archive hash table. */
947 #define archive_hash_table_free(t) bfd_hash_table_free (&(t)->table)
949 /* Generic function to add symbols from an archive file to the global
950 hash file. This function presumes that the archive symbol table
951 has already been read in (this is normally done by the
952 bfd_check_format entry point). It looks through the undefined and
953 common symbols and searches the archive symbol table for them. If
954 it finds an entry, it includes the associated object file in the
955 link.
957 The old linker looked through the archive symbol table for
958 undefined symbols. We do it the other way around, looking through
959 undefined symbols for symbols defined in the archive. The
960 advantage of the newer scheme is that we only have to look through
961 the list of undefined symbols once, whereas the old method had to
962 re-search the symbol table each time a new object file was added.
964 The CHECKFN argument is used to see if an object file should be
965 included. CHECKFN should set *PNEEDED to TRUE if the object file
966 should be included, and must also call the bfd_link_info
967 add_archive_element callback function and handle adding the symbols
968 to the global hash table. CHECKFN must notice if the callback
969 indicates a substitute BFD, and arrange to add those symbols instead
970 if it does so. CHECKFN should only return FALSE if some sort of
971 error occurs.
973 For some formats, such as a.out, it is possible to look through an
974 object file but not actually include it in the link. The
975 archive_pass field in a BFD is used to avoid checking the symbols
976 of an object files too many times. When an object is included in
977 the link, archive_pass is set to -1. If an object is scanned but
978 not included, archive_pass is set to the pass number. The pass
979 number is incremented each time a new object file is included. The
980 pass number is used because when a new object file is included it
981 may create new undefined symbols which cause a previously examined
982 object file to be included. */
984 bfd_boolean
985 _bfd_generic_link_add_archive_symbols
986 (bfd *abfd,
987 struct bfd_link_info *info,
988 bfd_boolean (*checkfn) (bfd *, struct bfd_link_info *, bfd_boolean *))
990 carsym *arsyms;
991 carsym *arsym_end;
992 register carsym *arsym;
993 int pass;
994 struct archive_hash_table arsym_hash;
995 unsigned int indx;
996 struct bfd_link_hash_entry **pundef;
998 if (! bfd_has_map (abfd))
1000 /* An empty archive is a special case. */
1001 if (bfd_openr_next_archived_file (abfd, NULL) == NULL)
1002 return TRUE;
1003 bfd_set_error (bfd_error_no_armap);
1004 return FALSE;
1007 arsyms = bfd_ardata (abfd)->symdefs;
1008 arsym_end = arsyms + bfd_ardata (abfd)->symdef_count;
1010 /* In order to quickly determine whether an symbol is defined in
1011 this archive, we build a hash table of the symbols. */
1012 if (! archive_hash_table_init (&arsym_hash, archive_hash_newfunc,
1013 sizeof (struct archive_hash_entry)))
1014 return FALSE;
1015 for (arsym = arsyms, indx = 0; arsym < arsym_end; arsym++, indx++)
1017 struct archive_hash_entry *arh;
1018 struct archive_list *l, **pp;
1020 arh = archive_hash_lookup (&arsym_hash, arsym->name, TRUE, FALSE);
1021 if (arh == NULL)
1022 goto error_return;
1023 l = ((struct archive_list *)
1024 archive_hash_allocate (&arsym_hash, sizeof (struct archive_list)));
1025 if (l == NULL)
1026 goto error_return;
1027 l->indx = indx;
1028 for (pp = &arh->defs; *pp != NULL; pp = &(*pp)->next)
1030 *pp = l;
1031 l->next = NULL;
1034 /* The archive_pass field in the archive itself is used to
1035 initialize PASS, sine we may search the same archive multiple
1036 times. */
1037 pass = abfd->archive_pass + 1;
1039 /* New undefined symbols are added to the end of the list, so we
1040 only need to look through it once. */
1041 pundef = &info->hash->undefs;
1042 while (*pundef != NULL)
1044 struct bfd_link_hash_entry *h;
1045 struct archive_hash_entry *arh;
1046 struct archive_list *l;
1048 h = *pundef;
1050 /* When a symbol is defined, it is not necessarily removed from
1051 the list. */
1052 if (h->type != bfd_link_hash_undefined
1053 && h->type != bfd_link_hash_common)
1055 /* Remove this entry from the list, for general cleanliness
1056 and because we are going to look through the list again
1057 if we search any more libraries. We can't remove the
1058 entry if it is the tail, because that would lose any
1059 entries we add to the list later on (it would also cause
1060 us to lose track of whether the symbol has been
1061 referenced). */
1062 if (*pundef != info->hash->undefs_tail)
1063 *pundef = (*pundef)->u.undef.next;
1064 else
1065 pundef = &(*pundef)->u.undef.next;
1066 continue;
1069 /* Look for this symbol in the archive symbol map. */
1070 arh = archive_hash_lookup (&arsym_hash, h->root.string, FALSE, FALSE);
1071 if (arh == NULL)
1073 /* If we haven't found the exact symbol we're looking for,
1074 let's look for its import thunk */
1075 if (info->pei386_auto_import)
1077 bfd_size_type amt = strlen (h->root.string) + 10;
1078 char *buf = (char *) bfd_malloc (amt);
1079 if (buf == NULL)
1080 return FALSE;
1082 sprintf (buf, "__imp_%s", h->root.string);
1083 arh = archive_hash_lookup (&arsym_hash, buf, FALSE, FALSE);
1084 free(buf);
1086 if (arh == NULL)
1088 pundef = &(*pundef)->u.undef.next;
1089 continue;
1092 /* Look at all the objects which define this symbol. */
1093 for (l = arh->defs; l != NULL; l = l->next)
1095 bfd *element;
1096 bfd_boolean needed;
1098 /* If the symbol has gotten defined along the way, quit. */
1099 if (h->type != bfd_link_hash_undefined
1100 && h->type != bfd_link_hash_common)
1101 break;
1103 element = bfd_get_elt_at_index (abfd, l->indx);
1104 if (element == NULL)
1105 goto error_return;
1107 /* If we've already included this element, or if we've
1108 already checked it on this pass, continue. */
1109 if (element->archive_pass == -1
1110 || element->archive_pass == pass)
1111 continue;
1113 /* If we can't figure this element out, just ignore it. */
1114 if (! bfd_check_format (element, bfd_object))
1116 element->archive_pass = -1;
1117 continue;
1120 /* CHECKFN will see if this element should be included, and
1121 go ahead and include it if appropriate. */
1122 if (! (*checkfn) (element, info, &needed))
1123 goto error_return;
1125 if (! needed)
1126 element->archive_pass = pass;
1127 else
1129 element->archive_pass = -1;
1131 /* Increment the pass count to show that we may need to
1132 recheck object files which were already checked. */
1133 ++pass;
1137 pundef = &(*pundef)->u.undef.next;
1140 archive_hash_table_free (&arsym_hash);
1142 /* Save PASS in case we are called again. */
1143 abfd->archive_pass = pass;
1145 return TRUE;
1147 error_return:
1148 archive_hash_table_free (&arsym_hash);
1149 return FALSE;
1152 /* See if we should include an archive element. This version is used
1153 when we do not want to automatically collect constructors based on
1154 the symbol name, presumably because we have some other mechanism
1155 for finding them. */
1157 static bfd_boolean
1158 generic_link_check_archive_element_no_collect (
1159 bfd *abfd,
1160 struct bfd_link_info *info,
1161 bfd_boolean *pneeded)
1163 return generic_link_check_archive_element (abfd, info, pneeded, FALSE);
1166 /* See if we should include an archive element. This version is used
1167 when we want to automatically collect constructors based on the
1168 symbol name, as collect2 does. */
1170 static bfd_boolean
1171 generic_link_check_archive_element_collect (bfd *abfd,
1172 struct bfd_link_info *info,
1173 bfd_boolean *pneeded)
1175 return generic_link_check_archive_element (abfd, info, pneeded, TRUE);
1178 /* See if we should include an archive element. Optionally collect
1179 constructors. */
1181 static bfd_boolean
1182 generic_link_check_archive_element (bfd *abfd,
1183 struct bfd_link_info *info,
1184 bfd_boolean *pneeded,
1185 bfd_boolean collect)
1187 asymbol **pp, **ppend;
1189 *pneeded = FALSE;
1191 if (!bfd_generic_link_read_symbols (abfd))
1192 return FALSE;
1194 pp = _bfd_generic_link_get_symbols (abfd);
1195 ppend = pp + _bfd_generic_link_get_symcount (abfd);
1196 for (; pp < ppend; pp++)
1198 asymbol *p;
1199 struct bfd_link_hash_entry *h;
1201 p = *pp;
1203 /* We are only interested in globally visible symbols. */
1204 if (! bfd_is_com_section (p->section)
1205 && (p->flags & (BSF_GLOBAL | BSF_INDIRECT | BSF_WEAK)) == 0)
1206 continue;
1208 /* We are only interested if we know something about this
1209 symbol, and it is undefined or common. An undefined weak
1210 symbol (type bfd_link_hash_undefweak) is not considered to be
1211 a reference when pulling files out of an archive. See the
1212 SVR4 ABI, p. 4-27. */
1213 h = bfd_link_hash_lookup (info->hash, bfd_asymbol_name (p), FALSE,
1214 FALSE, TRUE);
1215 if (h == NULL
1216 || (h->type != bfd_link_hash_undefined
1217 && h->type != bfd_link_hash_common))
1218 continue;
1220 /* P is a symbol we are looking for. */
1222 if (! bfd_is_com_section (p->section))
1224 bfd_size_type symcount;
1225 asymbol **symbols;
1226 bfd *oldbfd = abfd;
1228 /* This object file defines this symbol, so pull it in. */
1229 if (!(*info->callbacks
1230 ->add_archive_element) (info, abfd, bfd_asymbol_name (p),
1231 &abfd))
1232 return FALSE;
1233 /* Potentially, the add_archive_element hook may have set a
1234 substitute BFD for us. */
1235 if (abfd != oldbfd
1236 && !bfd_generic_link_read_symbols (abfd))
1237 return FALSE;
1238 symcount = _bfd_generic_link_get_symcount (abfd);
1239 symbols = _bfd_generic_link_get_symbols (abfd);
1240 if (! generic_link_add_symbol_list (abfd, info, symcount,
1241 symbols, collect))
1242 return FALSE;
1243 *pneeded = TRUE;
1244 return TRUE;
1247 /* P is a common symbol. */
1249 if (h->type == bfd_link_hash_undefined)
1251 bfd *symbfd;
1252 bfd_vma size;
1253 unsigned int power;
1255 symbfd = h->u.undef.abfd;
1256 if (symbfd == NULL)
1258 /* This symbol was created as undefined from outside
1259 BFD. We assume that we should link in the object
1260 file. This is for the -u option in the linker. */
1261 if (!(*info->callbacks
1262 ->add_archive_element) (info, abfd, bfd_asymbol_name (p),
1263 &abfd))
1264 return FALSE;
1265 /* Potentially, the add_archive_element hook may have set a
1266 substitute BFD for us. But no symbols are going to get
1267 registered by anything we're returning to from here. */
1268 *pneeded = TRUE;
1269 return TRUE;
1272 /* Turn the symbol into a common symbol but do not link in
1273 the object file. This is how a.out works. Object
1274 formats that require different semantics must implement
1275 this function differently. This symbol is already on the
1276 undefs list. We add the section to a common section
1277 attached to symbfd to ensure that it is in a BFD which
1278 will be linked in. */
1279 h->type = bfd_link_hash_common;
1280 h->u.c.p = (struct bfd_link_hash_common_entry *)
1281 bfd_hash_allocate (&info->hash->table,
1282 sizeof (struct bfd_link_hash_common_entry));
1283 if (h->u.c.p == NULL)
1284 return FALSE;
1286 size = bfd_asymbol_value (p);
1287 h->u.c.size = size;
1289 power = bfd_log2 (size);
1290 if (power > 4)
1291 power = 4;
1292 h->u.c.p->alignment_power = power;
1294 if (p->section == bfd_com_section_ptr)
1295 h->u.c.p->section = bfd_make_section_old_way (symbfd, "COMMON");
1296 else
1297 h->u.c.p->section = bfd_make_section_old_way (symbfd,
1298 p->section->name);
1299 h->u.c.p->section->flags = SEC_ALLOC;
1301 else
1303 /* Adjust the size of the common symbol if necessary. This
1304 is how a.out works. Object formats that require
1305 different semantics must implement this function
1306 differently. */
1307 if (bfd_asymbol_value (p) > h->u.c.size)
1308 h->u.c.size = bfd_asymbol_value (p);
1312 /* This archive element is not needed. */
1313 return TRUE;
1316 /* Add the symbols from an object file to the global hash table. ABFD
1317 is the object file. INFO is the linker information. SYMBOL_COUNT
1318 is the number of symbols. SYMBOLS is the list of symbols. COLLECT
1319 is TRUE if constructors should be automatically collected by name
1320 as is done by collect2. */
1322 static bfd_boolean
1323 generic_link_add_symbol_list (bfd *abfd,
1324 struct bfd_link_info *info,
1325 bfd_size_type symbol_count,
1326 asymbol **symbols,
1327 bfd_boolean collect)
1329 asymbol **pp, **ppend;
1331 pp = symbols;
1332 ppend = symbols + symbol_count;
1333 for (; pp < ppend; pp++)
1335 asymbol *p;
1337 p = *pp;
1339 if ((p->flags & (BSF_INDIRECT
1340 | BSF_WARNING
1341 | BSF_GLOBAL
1342 | BSF_CONSTRUCTOR
1343 | BSF_WEAK)) != 0
1344 || bfd_is_und_section (bfd_get_section (p))
1345 || bfd_is_com_section (bfd_get_section (p))
1346 || bfd_is_ind_section (bfd_get_section (p)))
1348 const char *name;
1349 const char *string;
1350 struct generic_link_hash_entry *h;
1351 struct bfd_link_hash_entry *bh;
1353 string = name = bfd_asymbol_name (p);
1354 if (((p->flags & BSF_INDIRECT) != 0
1355 || bfd_is_ind_section (p->section))
1356 && pp + 1 < ppend)
1358 pp++;
1359 string = bfd_asymbol_name (*pp);
1361 else if ((p->flags & BSF_WARNING) != 0
1362 && pp + 1 < ppend)
1364 /* The name of P is actually the warning string, and the
1365 next symbol is the one to warn about. */
1366 pp++;
1367 name = bfd_asymbol_name (*pp);
1370 bh = NULL;
1371 if (! (_bfd_generic_link_add_one_symbol
1372 (info, abfd, name, p->flags, bfd_get_section (p),
1373 p->value, string, FALSE, collect, &bh)))
1374 return FALSE;
1375 h = (struct generic_link_hash_entry *) bh;
1377 /* If this is a constructor symbol, and the linker didn't do
1378 anything with it, then we want to just pass the symbol
1379 through to the output file. This will happen when
1380 linking with -r. */
1381 if ((p->flags & BSF_CONSTRUCTOR) != 0
1382 && (h == NULL || h->root.type == bfd_link_hash_new))
1384 p->udata.p = NULL;
1385 continue;
1388 /* Save the BFD symbol so that we don't lose any backend
1389 specific information that may be attached to it. We only
1390 want this one if it gives more information than the
1391 existing one; we don't want to replace a defined symbol
1392 with an undefined one. This routine may be called with a
1393 hash table other than the generic hash table, so we only
1394 do this if we are certain that the hash table is a
1395 generic one. */
1396 if (info->output_bfd->xvec == abfd->xvec)
1398 if (h->sym == NULL
1399 || (! bfd_is_und_section (bfd_get_section (p))
1400 && (! bfd_is_com_section (bfd_get_section (p))
1401 || bfd_is_und_section (bfd_get_section (h->sym)))))
1403 h->sym = p;
1404 /* BSF_OLD_COMMON is a hack to support COFF reloc
1405 reading, and it should go away when the COFF
1406 linker is switched to the new version. */
1407 if (bfd_is_com_section (bfd_get_section (p)))
1408 p->flags |= BSF_OLD_COMMON;
1412 /* Store a back pointer from the symbol to the hash
1413 table entry for the benefit of relaxation code until
1414 it gets rewritten to not use asymbol structures.
1415 Setting this is also used to check whether these
1416 symbols were set up by the generic linker. */
1417 p->udata.p = h;
1421 return TRUE;
1424 /* We use a state table to deal with adding symbols from an object
1425 file. The first index into the state table describes the symbol
1426 from the object file. The second index into the state table is the
1427 type of the symbol in the hash table. */
1429 /* The symbol from the object file is turned into one of these row
1430 values. */
1432 enum link_row
1434 UNDEF_ROW, /* Undefined. */
1435 UNDEFW_ROW, /* Weak undefined. */
1436 DEF_ROW, /* Defined. */
1437 DEFW_ROW, /* Weak defined. */
1438 COMMON_ROW, /* Common. */
1439 INDR_ROW, /* Indirect. */
1440 WARN_ROW, /* Warning. */
1441 SET_ROW /* Member of set. */
1444 /* apparently needed for Hitachi 3050R(HI-UX/WE2)? */
1445 #undef FAIL
1447 /* The actions to take in the state table. */
1449 enum link_action
1451 FAIL, /* Abort. */
1452 UND, /* Mark symbol undefined. */
1453 WEAK, /* Mark symbol weak undefined. */
1454 DEF, /* Mark symbol defined. */
1455 DEFW, /* Mark symbol weak defined. */
1456 COM, /* Mark symbol common. */
1457 REF, /* Mark defined symbol referenced. */
1458 CREF, /* Possibly warn about common reference to defined symbol. */
1459 CDEF, /* Define existing common symbol. */
1460 NOACT, /* No action. */
1461 BIG, /* Mark symbol common using largest size. */
1462 MDEF, /* Multiple definition error. */
1463 MIND, /* Multiple indirect symbols. */
1464 IND, /* Make indirect symbol. */
1465 CIND, /* Make indirect symbol from existing common symbol. */
1466 SET, /* Add value to set. */
1467 MWARN, /* Make warning symbol. */
1468 WARN, /* Issue warning. */
1469 CWARN, /* Warn if referenced, else MWARN. */
1470 CYCLE, /* Repeat with symbol pointed to. */
1471 REFC, /* Mark indirect symbol referenced and then CYCLE. */
1472 WARNC /* Issue warning and then CYCLE. */
1475 /* The state table itself. The first index is a link_row and the
1476 second index is a bfd_link_hash_type. */
1478 static const enum link_action link_action[8][8] =
1480 /* current\prev new undef undefw def defw com indr warn */
1481 /* UNDEF_ROW */ {UND, NOACT, UND, REF, REF, NOACT, REFC, WARNC },
1482 /* UNDEFW_ROW */ {WEAK, NOACT, NOACT, REF, REF, NOACT, REFC, WARNC },
1483 /* DEF_ROW */ {DEF, DEF, DEF, MDEF, DEF, CDEF, MDEF, CYCLE },
1484 /* DEFW_ROW */ {DEFW, DEFW, DEFW, NOACT, NOACT, NOACT, NOACT, CYCLE },
1485 /* COMMON_ROW */ {COM, COM, COM, CREF, COM, BIG, REFC, WARNC },
1486 /* INDR_ROW */ {IND, IND, IND, MDEF, IND, CIND, MIND, CYCLE },
1487 /* WARN_ROW */ {MWARN, WARN, WARN, CWARN, CWARN, WARN, CWARN, NOACT },
1488 /* SET_ROW */ {SET, SET, SET, SET, SET, SET, CYCLE, CYCLE }
1491 /* Most of the entries in the LINK_ACTION table are straightforward,
1492 but a few are somewhat subtle.
1494 A reference to an indirect symbol (UNDEF_ROW/indr or
1495 UNDEFW_ROW/indr) is counted as a reference both to the indirect
1496 symbol and to the symbol the indirect symbol points to.
1498 A reference to a warning symbol (UNDEF_ROW/warn or UNDEFW_ROW/warn)
1499 causes the warning to be issued.
1501 A common definition of an indirect symbol (COMMON_ROW/indr) is
1502 treated as a multiple definition error. Likewise for an indirect
1503 definition of a common symbol (INDR_ROW/com).
1505 An indirect definition of a warning (INDR_ROW/warn) does not cause
1506 the warning to be issued.
1508 If a warning is created for an indirect symbol (WARN_ROW/indr) no
1509 warning is created for the symbol the indirect symbol points to.
1511 Adding an entry to a set does not count as a reference to a set,
1512 and no warning is issued (SET_ROW/warn). */
1514 /* Return the BFD in which a hash entry has been defined, if known. */
1516 static bfd *
1517 hash_entry_bfd (struct bfd_link_hash_entry *h)
1519 while (h->type == bfd_link_hash_warning)
1520 h = h->u.i.link;
1521 switch (h->type)
1523 default:
1524 return NULL;
1525 case bfd_link_hash_undefined:
1526 case bfd_link_hash_undefweak:
1527 return h->u.undef.abfd;
1528 case bfd_link_hash_defined:
1529 case bfd_link_hash_defweak:
1530 return h->u.def.section->owner;
1531 case bfd_link_hash_common:
1532 return h->u.c.p->section->owner;
1534 /*NOTREACHED*/
1537 /* Add a symbol to the global hash table.
1538 ABFD is the BFD the symbol comes from.
1539 NAME is the name of the symbol.
1540 FLAGS is the BSF_* bits associated with the symbol.
1541 SECTION is the section in which the symbol is defined; this may be
1542 bfd_und_section_ptr or bfd_com_section_ptr.
1543 VALUE is the value of the symbol, relative to the section.
1544 STRING is used for either an indirect symbol, in which case it is
1545 the name of the symbol to indirect to, or a warning symbol, in
1546 which case it is the warning string.
1547 COPY is TRUE if NAME or STRING must be copied into locally
1548 allocated memory if they need to be saved.
1549 COLLECT is TRUE if we should automatically collect gcc constructor
1550 or destructor names as collect2 does.
1551 HASHP, if not NULL, is a place to store the created hash table
1552 entry; if *HASHP is not NULL, the caller has already looked up
1553 the hash table entry, and stored it in *HASHP. */
1555 bfd_boolean
1556 _bfd_generic_link_add_one_symbol (struct bfd_link_info *info,
1557 bfd *abfd,
1558 const char *name,
1559 flagword flags,
1560 asection *section,
1561 bfd_vma value,
1562 const char *string,
1563 bfd_boolean copy,
1564 bfd_boolean collect,
1565 struct bfd_link_hash_entry **hashp)
1567 enum link_row row;
1568 struct bfd_link_hash_entry *h;
1569 bfd_boolean cycle;
1571 if (bfd_is_ind_section (section)
1572 || (flags & BSF_INDIRECT) != 0)
1573 row = INDR_ROW;
1574 else if ((flags & BSF_WARNING) != 0)
1575 row = WARN_ROW;
1576 else if ((flags & BSF_CONSTRUCTOR) != 0)
1577 row = SET_ROW;
1578 else if (bfd_is_und_section (section))
1580 if ((flags & BSF_WEAK) != 0)
1581 row = UNDEFW_ROW;
1582 else
1583 row = UNDEF_ROW;
1585 else if ((flags & BSF_WEAK) != 0)
1586 row = DEFW_ROW;
1587 else if (bfd_is_com_section (section))
1588 row = COMMON_ROW;
1589 else
1590 row = DEF_ROW;
1592 if (hashp != NULL && *hashp != NULL)
1593 h = *hashp;
1594 else
1596 if (row == UNDEF_ROW || row == UNDEFW_ROW)
1597 h = bfd_wrapped_link_hash_lookup (abfd, info, name, TRUE, copy, FALSE);
1598 else
1599 h = bfd_link_hash_lookup (info->hash, name, TRUE, copy, FALSE);
1600 if (h == NULL)
1602 if (hashp != NULL)
1603 *hashp = NULL;
1604 return FALSE;
1608 if (info->notice_all
1609 || (info->notice_hash != NULL
1610 && bfd_hash_lookup (info->notice_hash, name, FALSE, FALSE) != NULL))
1612 if (! (*info->callbacks->notice) (info, h->root.string, abfd, section,
1613 value))
1614 return FALSE;
1617 if (hashp != NULL)
1618 *hashp = h;
1622 enum link_action action;
1624 cycle = FALSE;
1625 action = link_action[(int) row][(int) h->type];
1626 switch (action)
1628 case FAIL:
1629 abort ();
1631 case NOACT:
1632 /* Do nothing. */
1633 break;
1635 case UND:
1636 /* Make a new undefined symbol. */
1637 h->type = bfd_link_hash_undefined;
1638 h->u.undef.abfd = abfd;
1639 bfd_link_add_undef (info->hash, h);
1640 break;
1642 case WEAK:
1643 /* Make a new weak undefined symbol. */
1644 h->type = bfd_link_hash_undefweak;
1645 h->u.undef.abfd = abfd;
1646 h->u.undef.weak = abfd;
1647 break;
1649 case CDEF:
1650 /* We have found a definition for a symbol which was
1651 previously common. */
1652 BFD_ASSERT (h->type == bfd_link_hash_common);
1653 if (! ((*info->callbacks->multiple_common)
1654 (info, h->root.string,
1655 h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size,
1656 abfd, bfd_link_hash_defined, 0)))
1657 return FALSE;
1658 /* Fall through. */
1659 case DEF:
1660 case DEFW:
1662 enum bfd_link_hash_type oldtype;
1664 /* Define a symbol. */
1665 oldtype = h->type;
1666 if (action == DEFW)
1667 h->type = bfd_link_hash_defweak;
1668 else
1669 h->type = bfd_link_hash_defined;
1670 h->u.def.section = section;
1671 h->u.def.value = value;
1673 /* If we have been asked to, we act like collect2 and
1674 identify all functions that might be global
1675 constructors and destructors and pass them up in a
1676 callback. We only do this for certain object file
1677 types, since many object file types can handle this
1678 automatically. */
1679 if (collect && name[0] == '_')
1681 const char *s;
1683 /* A constructor or destructor name starts like this:
1684 _+GLOBAL_[_.$][ID][_.$] where the first [_.$] and
1685 the second are the same character (we accept any
1686 character there, in case a new object file format
1687 comes along with even worse naming restrictions). */
1689 #define CONS_PREFIX "GLOBAL_"
1690 #define CONS_PREFIX_LEN (sizeof CONS_PREFIX - 1)
1692 s = name + 1;
1693 while (*s == '_')
1694 ++s;
1695 if (s[0] == 'G' && CONST_STRNEQ (s, CONS_PREFIX))
1697 char c;
1699 c = s[CONS_PREFIX_LEN + 1];
1700 if ((c == 'I' || c == 'D')
1701 && s[CONS_PREFIX_LEN] == s[CONS_PREFIX_LEN + 2])
1703 /* If this is a definition of a symbol which
1704 was previously weakly defined, we are in
1705 trouble. We have already added a
1706 constructor entry for the weak defined
1707 symbol, and now we are trying to add one
1708 for the new symbol. Fortunately, this case
1709 should never arise in practice. */
1710 if (oldtype == bfd_link_hash_defweak)
1711 abort ();
1713 if (! ((*info->callbacks->constructor)
1714 (info, c == 'I',
1715 h->root.string, abfd, section, value)))
1716 return FALSE;
1722 break;
1724 case COM:
1725 /* We have found a common definition for a symbol. */
1726 if (h->type == bfd_link_hash_new)
1727 bfd_link_add_undef (info->hash, h);
1728 h->type = bfd_link_hash_common;
1729 h->u.c.p = (struct bfd_link_hash_common_entry *)
1730 bfd_hash_allocate (&info->hash->table,
1731 sizeof (struct bfd_link_hash_common_entry));
1732 if (h->u.c.p == NULL)
1733 return FALSE;
1735 h->u.c.size = value;
1737 /* Select a default alignment based on the size. This may
1738 be overridden by the caller. */
1740 unsigned int power;
1742 power = bfd_log2 (value);
1743 if (power > 4)
1744 power = 4;
1745 h->u.c.p->alignment_power = power;
1748 /* The section of a common symbol is only used if the common
1749 symbol is actually allocated. It basically provides a
1750 hook for the linker script to decide which output section
1751 the common symbols should be put in. In most cases, the
1752 section of a common symbol will be bfd_com_section_ptr,
1753 the code here will choose a common symbol section named
1754 "COMMON", and the linker script will contain *(COMMON) in
1755 the appropriate place. A few targets use separate common
1756 sections for small symbols, and they require special
1757 handling. */
1758 if (section == bfd_com_section_ptr)
1760 h->u.c.p->section = bfd_make_section_old_way (abfd, "COMMON");
1761 h->u.c.p->section->flags = SEC_ALLOC;
1763 else if (section->owner != abfd)
1765 h->u.c.p->section = bfd_make_section_old_way (abfd,
1766 section->name);
1767 h->u.c.p->section->flags = SEC_ALLOC;
1769 else
1770 h->u.c.p->section = section;
1771 break;
1773 case REF:
1774 /* A reference to a defined symbol. */
1775 if (h->u.undef.next == NULL && info->hash->undefs_tail != h)
1776 h->u.undef.next = h;
1777 break;
1779 case BIG:
1780 /* We have found a common definition for a symbol which
1781 already had a common definition. Use the maximum of the
1782 two sizes, and use the section required by the larger symbol. */
1783 BFD_ASSERT (h->type == bfd_link_hash_common);
1784 if (! ((*info->callbacks->multiple_common)
1785 (info, h->root.string,
1786 h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size,
1787 abfd, bfd_link_hash_common, value)))
1788 return FALSE;
1789 if (value > h->u.c.size)
1791 unsigned int power;
1793 h->u.c.size = value;
1795 /* Select a default alignment based on the size. This may
1796 be overridden by the caller. */
1797 power = bfd_log2 (value);
1798 if (power > 4)
1799 power = 4;
1800 h->u.c.p->alignment_power = power;
1802 /* Some systems have special treatment for small commons,
1803 hence we want to select the section used by the larger
1804 symbol. This makes sure the symbol does not go in a
1805 small common section if it is now too large. */
1806 if (section == bfd_com_section_ptr)
1808 h->u.c.p->section
1809 = bfd_make_section_old_way (abfd, "COMMON");
1810 h->u.c.p->section->flags = SEC_ALLOC;
1812 else if (section->owner != abfd)
1814 h->u.c.p->section
1815 = bfd_make_section_old_way (abfd, section->name);
1816 h->u.c.p->section->flags = SEC_ALLOC;
1818 else
1819 h->u.c.p->section = section;
1821 break;
1823 case CREF:
1825 bfd *obfd;
1827 /* We have found a common definition for a symbol which
1828 was already defined. FIXME: It would nice if we could
1829 report the BFD which defined an indirect symbol, but we
1830 don't have anywhere to store the information. */
1831 if (h->type == bfd_link_hash_defined
1832 || h->type == bfd_link_hash_defweak)
1833 obfd = h->u.def.section->owner;
1834 else
1835 obfd = NULL;
1836 if (! ((*info->callbacks->multiple_common)
1837 (info, h->root.string, obfd, h->type, 0,
1838 abfd, bfd_link_hash_common, value)))
1839 return FALSE;
1841 break;
1843 case MIND:
1844 /* Multiple indirect symbols. This is OK if they both point
1845 to the same symbol. */
1846 if (strcmp (h->u.i.link->root.string, string) == 0)
1847 break;
1848 /* Fall through. */
1849 case MDEF:
1850 /* Handle a multiple definition. */
1851 if (!info->allow_multiple_definition)
1853 asection *msec = NULL;
1854 bfd_vma mval = 0;
1856 switch (h->type)
1858 case bfd_link_hash_defined:
1859 msec = h->u.def.section;
1860 mval = h->u.def.value;
1861 break;
1862 case bfd_link_hash_indirect:
1863 msec = bfd_ind_section_ptr;
1864 mval = 0;
1865 break;
1866 default:
1867 abort ();
1870 /* Ignore a redefinition of an absolute symbol to the
1871 same value; it's harmless. */
1872 if (h->type == bfd_link_hash_defined
1873 && bfd_is_abs_section (msec)
1874 && bfd_is_abs_section (section)
1875 && value == mval)
1876 break;
1878 if (! ((*info->callbacks->multiple_definition)
1879 (info, h->root.string, msec->owner, msec, mval,
1880 abfd, section, value)))
1881 return FALSE;
1883 break;
1885 case CIND:
1886 /* Create an indirect symbol from an existing common symbol. */
1887 BFD_ASSERT (h->type == bfd_link_hash_common);
1888 if (! ((*info->callbacks->multiple_common)
1889 (info, h->root.string,
1890 h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size,
1891 abfd, bfd_link_hash_indirect, 0)))
1892 return FALSE;
1893 /* Fall through. */
1894 case IND:
1895 /* Create an indirect symbol. */
1897 struct bfd_link_hash_entry *inh;
1899 /* STRING is the name of the symbol we want to indirect
1900 to. */
1901 inh = bfd_wrapped_link_hash_lookup (abfd, info, string, TRUE,
1902 copy, FALSE);
1903 if (inh == NULL)
1904 return FALSE;
1905 if (inh->type == bfd_link_hash_indirect
1906 && inh->u.i.link == h)
1908 (*_bfd_error_handler)
1909 (_("%B: indirect symbol `%s' to `%s' is a loop"),
1910 abfd, name, string);
1911 bfd_set_error (bfd_error_invalid_operation);
1912 return FALSE;
1914 if (inh->type == bfd_link_hash_new)
1916 inh->type = bfd_link_hash_undefined;
1917 inh->u.undef.abfd = abfd;
1918 bfd_link_add_undef (info->hash, inh);
1921 /* If the indirect symbol has been referenced, we need to
1922 push the reference down to the symbol we are
1923 referencing. */
1924 if (h->type != bfd_link_hash_new)
1926 row = UNDEF_ROW;
1927 cycle = TRUE;
1930 h->type = bfd_link_hash_indirect;
1931 h->u.i.link = inh;
1933 break;
1935 case SET:
1936 /* Add an entry to a set. */
1937 if (! (*info->callbacks->add_to_set) (info, h, BFD_RELOC_CTOR,
1938 abfd, section, value))
1939 return FALSE;
1940 break;
1942 case WARNC:
1943 /* Issue a warning and cycle. */
1944 if (h->u.i.warning != NULL)
1946 if (! (*info->callbacks->warning) (info, h->u.i.warning,
1947 h->root.string, abfd,
1948 NULL, 0))
1949 return FALSE;
1950 /* Only issue a warning once. */
1951 h->u.i.warning = NULL;
1953 /* Fall through. */
1954 case CYCLE:
1955 /* Try again with the referenced symbol. */
1956 h = h->u.i.link;
1957 cycle = TRUE;
1958 break;
1960 case REFC:
1961 /* A reference to an indirect symbol. */
1962 if (h->u.undef.next == NULL && info->hash->undefs_tail != h)
1963 h->u.undef.next = h;
1964 h = h->u.i.link;
1965 cycle = TRUE;
1966 break;
1968 case WARN:
1969 /* Issue a warning. */
1970 if (! (*info->callbacks->warning) (info, string, h->root.string,
1971 hash_entry_bfd (h), NULL, 0))
1972 return FALSE;
1973 break;
1975 case CWARN:
1976 /* Warn if this symbol has been referenced already,
1977 otherwise add a warning. A symbol has been referenced if
1978 the u.undef.next field is not NULL, or it is the tail of the
1979 undefined symbol list. The REF case above helps to
1980 ensure this. */
1981 if (h->u.undef.next != NULL || info->hash->undefs_tail == h)
1983 if (! (*info->callbacks->warning) (info, string, h->root.string,
1984 hash_entry_bfd (h), NULL, 0))
1985 return FALSE;
1986 break;
1988 /* Fall through. */
1989 case MWARN:
1990 /* Make a warning symbol. */
1992 struct bfd_link_hash_entry *sub;
1994 /* STRING is the warning to give. */
1995 sub = ((struct bfd_link_hash_entry *)
1996 ((*info->hash->table.newfunc)
1997 (NULL, &info->hash->table, h->root.string)));
1998 if (sub == NULL)
1999 return FALSE;
2000 *sub = *h;
2001 sub->type = bfd_link_hash_warning;
2002 sub->u.i.link = h;
2003 if (! copy)
2004 sub->u.i.warning = string;
2005 else
2007 char *w;
2008 size_t len = strlen (string) + 1;
2010 w = (char *) bfd_hash_allocate (&info->hash->table, len);
2011 if (w == NULL)
2012 return FALSE;
2013 memcpy (w, string, len);
2014 sub->u.i.warning = w;
2017 bfd_hash_replace (&info->hash->table,
2018 (struct bfd_hash_entry *) h,
2019 (struct bfd_hash_entry *) sub);
2020 if (hashp != NULL)
2021 *hashp = sub;
2023 break;
2026 while (cycle);
2028 return TRUE;
2031 /* Generic final link routine. */
2033 bfd_boolean
2034 _bfd_generic_final_link (bfd *abfd, struct bfd_link_info *info)
2036 bfd *sub;
2037 asection *o;
2038 struct bfd_link_order *p;
2039 size_t outsymalloc;
2040 struct generic_write_global_symbol_info wginfo;
2042 bfd_get_outsymbols (abfd) = NULL;
2043 bfd_get_symcount (abfd) = 0;
2044 outsymalloc = 0;
2046 /* Mark all sections which will be included in the output file. */
2047 for (o = abfd->sections; o != NULL; o = o->next)
2048 for (p = o->map_head.link_order; p != NULL; p = p->next)
2049 if (p->type == bfd_indirect_link_order)
2050 p->u.indirect.section->linker_mark = TRUE;
2052 /* Build the output symbol table. */
2053 for (sub = info->input_bfds; sub != NULL; sub = sub->link_next)
2054 if (! _bfd_generic_link_output_symbols (abfd, sub, info, &outsymalloc))
2055 return FALSE;
2057 /* Accumulate the global symbols. */
2058 wginfo.info = info;
2059 wginfo.output_bfd = abfd;
2060 wginfo.psymalloc = &outsymalloc;
2061 _bfd_generic_link_hash_traverse (_bfd_generic_hash_table (info),
2062 _bfd_generic_link_write_global_symbol,
2063 &wginfo);
2065 /* Make sure we have a trailing NULL pointer on OUTSYMBOLS. We
2066 shouldn't really need one, since we have SYMCOUNT, but some old
2067 code still expects one. */
2068 if (! generic_add_output_symbol (abfd, &outsymalloc, NULL))
2069 return FALSE;
2071 if (info->relocatable)
2073 /* Allocate space for the output relocs for each section. */
2074 for (o = abfd->sections; o != NULL; o = o->next)
2076 o->reloc_count = 0;
2077 for (p = o->map_head.link_order; p != NULL; p = p->next)
2079 if (p->type == bfd_section_reloc_link_order
2080 || p->type == bfd_symbol_reloc_link_order)
2081 ++o->reloc_count;
2082 else if (p->type == bfd_indirect_link_order)
2084 asection *input_section;
2085 bfd *input_bfd;
2086 long relsize;
2087 arelent **relocs;
2088 asymbol **symbols;
2089 long reloc_count;
2091 input_section = p->u.indirect.section;
2092 input_bfd = input_section->owner;
2093 relsize = bfd_get_reloc_upper_bound (input_bfd,
2094 input_section);
2095 if (relsize < 0)
2096 return FALSE;
2097 relocs = (arelent **) bfd_malloc (relsize);
2098 if (!relocs && relsize != 0)
2099 return FALSE;
2100 symbols = _bfd_generic_link_get_symbols (input_bfd);
2101 reloc_count = bfd_canonicalize_reloc (input_bfd,
2102 input_section,
2103 relocs,
2104 symbols);
2105 free (relocs);
2106 if (reloc_count < 0)
2107 return FALSE;
2108 BFD_ASSERT ((unsigned long) reloc_count
2109 == input_section->reloc_count);
2110 o->reloc_count += reloc_count;
2113 if (o->reloc_count > 0)
2115 bfd_size_type amt;
2117 amt = o->reloc_count;
2118 amt *= sizeof (arelent *);
2119 o->orelocation = (struct reloc_cache_entry **) bfd_alloc (abfd, amt);
2120 if (!o->orelocation)
2121 return FALSE;
2122 o->flags |= SEC_RELOC;
2123 /* Reset the count so that it can be used as an index
2124 when putting in the output relocs. */
2125 o->reloc_count = 0;
2130 /* Handle all the link order information for the sections. */
2131 for (o = abfd->sections; o != NULL; o = o->next)
2133 for (p = o->map_head.link_order; p != NULL; p = p->next)
2135 switch (p->type)
2137 case bfd_section_reloc_link_order:
2138 case bfd_symbol_reloc_link_order:
2139 if (! _bfd_generic_reloc_link_order (abfd, info, o, p))
2140 return FALSE;
2141 break;
2142 case bfd_indirect_link_order:
2143 if (! default_indirect_link_order (abfd, info, o, p, TRUE))
2144 return FALSE;
2145 break;
2146 default:
2147 if (! _bfd_default_link_order (abfd, info, o, p))
2148 return FALSE;
2149 break;
2154 return TRUE;
2157 /* Add an output symbol to the output BFD. */
2159 static bfd_boolean
2160 generic_add_output_symbol (bfd *output_bfd, size_t *psymalloc, asymbol *sym)
2162 if (bfd_get_symcount (output_bfd) >= *psymalloc)
2164 asymbol **newsyms;
2165 bfd_size_type amt;
2167 if (*psymalloc == 0)
2168 *psymalloc = 124;
2169 else
2170 *psymalloc *= 2;
2171 amt = *psymalloc;
2172 amt *= sizeof (asymbol *);
2173 newsyms = (asymbol **) bfd_realloc (bfd_get_outsymbols (output_bfd), amt);
2174 if (newsyms == NULL)
2175 return FALSE;
2176 bfd_get_outsymbols (output_bfd) = newsyms;
2179 bfd_get_outsymbols (output_bfd) [bfd_get_symcount (output_bfd)] = sym;
2180 if (sym != NULL)
2181 ++ bfd_get_symcount (output_bfd);
2183 return TRUE;
2186 /* Handle the symbols for an input BFD. */
2188 bfd_boolean
2189 _bfd_generic_link_output_symbols (bfd *output_bfd,
2190 bfd *input_bfd,
2191 struct bfd_link_info *info,
2192 size_t *psymalloc)
2194 asymbol **sym_ptr;
2195 asymbol **sym_end;
2197 if (!bfd_generic_link_read_symbols (input_bfd))
2198 return FALSE;
2200 /* Create a filename symbol if we are supposed to. */
2201 if (info->create_object_symbols_section != NULL)
2203 asection *sec;
2205 for (sec = input_bfd->sections; sec != NULL; sec = sec->next)
2207 if (sec->output_section == info->create_object_symbols_section)
2209 asymbol *newsym;
2211 newsym = bfd_make_empty_symbol (input_bfd);
2212 if (!newsym)
2213 return FALSE;
2214 newsym->name = input_bfd->filename;
2215 newsym->value = 0;
2216 newsym->flags = BSF_LOCAL | BSF_FILE;
2217 newsym->section = sec;
2219 if (! generic_add_output_symbol (output_bfd, psymalloc,
2220 newsym))
2221 return FALSE;
2223 break;
2228 /* Adjust the values of the globally visible symbols, and write out
2229 local symbols. */
2230 sym_ptr = _bfd_generic_link_get_symbols (input_bfd);
2231 sym_end = sym_ptr + _bfd_generic_link_get_symcount (input_bfd);
2232 for (; sym_ptr < sym_end; sym_ptr++)
2234 asymbol *sym;
2235 struct generic_link_hash_entry *h;
2236 bfd_boolean output;
2238 h = NULL;
2239 sym = *sym_ptr;
2240 if ((sym->flags & (BSF_INDIRECT
2241 | BSF_WARNING
2242 | BSF_GLOBAL
2243 | BSF_CONSTRUCTOR
2244 | BSF_WEAK)) != 0
2245 || bfd_is_und_section (bfd_get_section (sym))
2246 || bfd_is_com_section (bfd_get_section (sym))
2247 || bfd_is_ind_section (bfd_get_section (sym)))
2249 if (sym->udata.p != NULL)
2250 h = (struct generic_link_hash_entry *) sym->udata.p;
2251 else if ((sym->flags & BSF_CONSTRUCTOR) != 0)
2253 /* This case normally means that the main linker code
2254 deliberately ignored this constructor symbol. We
2255 should just pass it through. This will screw up if
2256 the constructor symbol is from a different,
2257 non-generic, object file format, but the case will
2258 only arise when linking with -r, which will probably
2259 fail anyhow, since there will be no way to represent
2260 the relocs in the output format being used. */
2261 h = NULL;
2263 else if (bfd_is_und_section (bfd_get_section (sym)))
2264 h = ((struct generic_link_hash_entry *)
2265 bfd_wrapped_link_hash_lookup (output_bfd, info,
2266 bfd_asymbol_name (sym),
2267 FALSE, FALSE, TRUE));
2268 else
2269 h = _bfd_generic_link_hash_lookup (_bfd_generic_hash_table (info),
2270 bfd_asymbol_name (sym),
2271 FALSE, FALSE, TRUE);
2273 if (h != NULL)
2275 /* Force all references to this symbol to point to
2276 the same area in memory. It is possible that
2277 this routine will be called with a hash table
2278 other than a generic hash table, so we double
2279 check that. */
2280 if (info->output_bfd->xvec == input_bfd->xvec)
2282 if (h->sym != NULL)
2283 *sym_ptr = sym = h->sym;
2286 switch (h->root.type)
2288 default:
2289 case bfd_link_hash_new:
2290 abort ();
2291 case bfd_link_hash_undefined:
2292 break;
2293 case bfd_link_hash_undefweak:
2294 sym->flags |= BSF_WEAK;
2295 break;
2296 case bfd_link_hash_indirect:
2297 h = (struct generic_link_hash_entry *) h->root.u.i.link;
2298 /* fall through */
2299 case bfd_link_hash_defined:
2300 sym->flags |= BSF_GLOBAL;
2301 sym->flags &=~ BSF_CONSTRUCTOR;
2302 sym->value = h->root.u.def.value;
2303 sym->section = h->root.u.def.section;
2304 break;
2305 case bfd_link_hash_defweak:
2306 sym->flags |= BSF_WEAK;
2307 sym->flags &=~ BSF_CONSTRUCTOR;
2308 sym->value = h->root.u.def.value;
2309 sym->section = h->root.u.def.section;
2310 break;
2311 case bfd_link_hash_common:
2312 sym->value = h->root.u.c.size;
2313 sym->flags |= BSF_GLOBAL;
2314 if (! bfd_is_com_section (sym->section))
2316 BFD_ASSERT (bfd_is_und_section (sym->section));
2317 sym->section = bfd_com_section_ptr;
2319 /* We do not set the section of the symbol to
2320 h->root.u.c.p->section. That value was saved so
2321 that we would know where to allocate the symbol
2322 if it was defined. In this case the type is
2323 still bfd_link_hash_common, so we did not define
2324 it, so we do not want to use that section. */
2325 break;
2330 /* This switch is straight from the old code in
2331 write_file_locals in ldsym.c. */
2332 if (info->strip == strip_all
2333 || (info->strip == strip_some
2334 && bfd_hash_lookup (info->keep_hash, bfd_asymbol_name (sym),
2335 FALSE, FALSE) == NULL))
2336 output = FALSE;
2337 else if ((sym->flags & (BSF_GLOBAL | BSF_WEAK)) != 0)
2339 /* If this symbol is marked as occurring now, rather
2340 than at the end, output it now. This is used for
2341 COFF C_EXT FCN symbols. FIXME: There must be a
2342 better way. */
2343 if (bfd_asymbol_bfd (sym) == input_bfd
2344 && (sym->flags & BSF_NOT_AT_END) != 0)
2345 output = TRUE;
2346 else
2347 output = FALSE;
2349 else if (bfd_is_ind_section (sym->section))
2350 output = FALSE;
2351 else if ((sym->flags & BSF_DEBUGGING) != 0)
2353 if (info->strip == strip_none)
2354 output = TRUE;
2355 else
2356 output = FALSE;
2358 else if (bfd_is_und_section (sym->section)
2359 || bfd_is_com_section (sym->section))
2360 output = FALSE;
2361 else if ((sym->flags & BSF_LOCAL) != 0)
2363 if ((sym->flags & BSF_WARNING) != 0)
2364 output = FALSE;
2365 else
2367 switch (info->discard)
2369 default:
2370 case discard_all:
2371 output = FALSE;
2372 break;
2373 case discard_sec_merge:
2374 output = TRUE;
2375 if (info->relocatable
2376 || ! (sym->section->flags & SEC_MERGE))
2377 break;
2378 /* FALLTHROUGH */
2379 case discard_l:
2380 if (bfd_is_local_label (input_bfd, sym))
2381 output = FALSE;
2382 else
2383 output = TRUE;
2384 break;
2385 case discard_none:
2386 output = TRUE;
2387 break;
2391 else if ((sym->flags & BSF_CONSTRUCTOR))
2393 if (info->strip != strip_all)
2394 output = TRUE;
2395 else
2396 output = FALSE;
2398 else
2399 abort ();
2401 /* If this symbol is in a section which is not being included
2402 in the output file, then we don't want to output the
2403 symbol. */
2404 if (!bfd_is_abs_section (sym->section)
2405 && bfd_section_removed_from_list (output_bfd,
2406 sym->section->output_section))
2407 output = FALSE;
2409 if (output)
2411 if (! generic_add_output_symbol (output_bfd, psymalloc, sym))
2412 return FALSE;
2413 if (h != NULL)
2414 h->written = TRUE;
2418 return TRUE;
2421 /* Set the section and value of a generic BFD symbol based on a linker
2422 hash table entry. */
2424 static void
2425 set_symbol_from_hash (asymbol *sym, struct bfd_link_hash_entry *h)
2427 switch (h->type)
2429 default:
2430 abort ();
2431 break;
2432 case bfd_link_hash_new:
2433 /* This can happen when a constructor symbol is seen but we are
2434 not building constructors. */
2435 if (sym->section != NULL)
2437 BFD_ASSERT ((sym->flags & BSF_CONSTRUCTOR) != 0);
2439 else
2441 sym->flags |= BSF_CONSTRUCTOR;
2442 sym->section = bfd_abs_section_ptr;
2443 sym->value = 0;
2445 break;
2446 case bfd_link_hash_undefined:
2447 sym->section = bfd_und_section_ptr;
2448 sym->value = 0;
2449 break;
2450 case bfd_link_hash_undefweak:
2451 sym->section = bfd_und_section_ptr;
2452 sym->value = 0;
2453 sym->flags |= BSF_WEAK;
2454 break;
2455 case bfd_link_hash_defined:
2456 sym->section = h->u.def.section;
2457 sym->value = h->u.def.value;
2458 break;
2459 case bfd_link_hash_defweak:
2460 sym->flags |= BSF_WEAK;
2461 sym->section = h->u.def.section;
2462 sym->value = h->u.def.value;
2463 break;
2464 case bfd_link_hash_common:
2465 sym->value = h->u.c.size;
2466 if (sym->section == NULL)
2467 sym->section = bfd_com_section_ptr;
2468 else if (! bfd_is_com_section (sym->section))
2470 BFD_ASSERT (bfd_is_und_section (sym->section));
2471 sym->section = bfd_com_section_ptr;
2473 /* Do not set the section; see _bfd_generic_link_output_symbols. */
2474 break;
2475 case bfd_link_hash_indirect:
2476 case bfd_link_hash_warning:
2477 /* FIXME: What should we do here? */
2478 break;
2482 /* Write out a global symbol, if it hasn't already been written out.
2483 This is called for each symbol in the hash table. */
2485 bfd_boolean
2486 _bfd_generic_link_write_global_symbol (struct generic_link_hash_entry *h,
2487 void *data)
2489 struct generic_write_global_symbol_info *wginfo =
2490 (struct generic_write_global_symbol_info *) data;
2491 asymbol *sym;
2493 if (h->root.type == bfd_link_hash_warning)
2494 h = (struct generic_link_hash_entry *) h->root.u.i.link;
2496 if (h->written)
2497 return TRUE;
2499 h->written = TRUE;
2501 if (wginfo->info->strip == strip_all
2502 || (wginfo->info->strip == strip_some
2503 && bfd_hash_lookup (wginfo->info->keep_hash, h->root.root.string,
2504 FALSE, FALSE) == NULL))
2505 return TRUE;
2507 if (h->sym != NULL)
2508 sym = h->sym;
2509 else
2511 sym = bfd_make_empty_symbol (wginfo->output_bfd);
2512 if (!sym)
2513 return FALSE;
2514 sym->name = h->root.root.string;
2515 sym->flags = 0;
2518 set_symbol_from_hash (sym, &h->root);
2520 sym->flags |= BSF_GLOBAL;
2522 if (! generic_add_output_symbol (wginfo->output_bfd, wginfo->psymalloc,
2523 sym))
2525 /* FIXME: No way to return failure. */
2526 abort ();
2529 return TRUE;
2532 /* Create a relocation. */
2534 bfd_boolean
2535 _bfd_generic_reloc_link_order (bfd *abfd,
2536 struct bfd_link_info *info,
2537 asection *sec,
2538 struct bfd_link_order *link_order)
2540 arelent *r;
2542 if (! info->relocatable)
2543 abort ();
2544 if (sec->orelocation == NULL)
2545 abort ();
2547 r = (arelent *) bfd_alloc (abfd, sizeof (arelent));
2548 if (r == NULL)
2549 return FALSE;
2551 r->address = link_order->offset;
2552 r->howto = bfd_reloc_type_lookup (abfd, link_order->u.reloc.p->reloc);
2553 if (r->howto == 0)
2555 bfd_set_error (bfd_error_bad_value);
2556 return FALSE;
2559 /* Get the symbol to use for the relocation. */
2560 if (link_order->type == bfd_section_reloc_link_order)
2561 r->sym_ptr_ptr = link_order->u.reloc.p->u.section->symbol_ptr_ptr;
2562 else
2564 struct generic_link_hash_entry *h;
2566 h = ((struct generic_link_hash_entry *)
2567 bfd_wrapped_link_hash_lookup (abfd, info,
2568 link_order->u.reloc.p->u.name,
2569 FALSE, FALSE, TRUE));
2570 if (h == NULL
2571 || ! h->written)
2573 if (! ((*info->callbacks->unattached_reloc)
2574 (info, link_order->u.reloc.p->u.name, NULL, NULL, 0)))
2575 return FALSE;
2576 bfd_set_error (bfd_error_bad_value);
2577 return FALSE;
2579 r->sym_ptr_ptr = &h->sym;
2582 /* If this is an inplace reloc, write the addend to the object file.
2583 Otherwise, store it in the reloc addend. */
2584 if (! r->howto->partial_inplace)
2585 r->addend = link_order->u.reloc.p->addend;
2586 else
2588 bfd_size_type size;
2589 bfd_reloc_status_type rstat;
2590 bfd_byte *buf;
2591 bfd_boolean ok;
2592 file_ptr loc;
2594 size = bfd_get_reloc_size (r->howto);
2595 buf = (bfd_byte *) bfd_zmalloc (size);
2596 if (buf == NULL)
2597 return FALSE;
2598 rstat = _bfd_relocate_contents (r->howto, abfd,
2599 (bfd_vma) link_order->u.reloc.p->addend,
2600 buf);
2601 switch (rstat)
2603 case bfd_reloc_ok:
2604 break;
2605 default:
2606 case bfd_reloc_outofrange:
2607 abort ();
2608 case bfd_reloc_overflow:
2609 if (! ((*info->callbacks->reloc_overflow)
2610 (info, NULL,
2611 (link_order->type == bfd_section_reloc_link_order
2612 ? bfd_section_name (abfd, link_order->u.reloc.p->u.section)
2613 : link_order->u.reloc.p->u.name),
2614 r->howto->name, link_order->u.reloc.p->addend,
2615 NULL, NULL, 0)))
2617 free (buf);
2618 return FALSE;
2620 break;
2622 loc = link_order->offset * bfd_octets_per_byte (abfd);
2623 ok = bfd_set_section_contents (abfd, sec, buf, loc, size);
2624 free (buf);
2625 if (! ok)
2626 return FALSE;
2628 r->addend = 0;
2631 sec->orelocation[sec->reloc_count] = r;
2632 ++sec->reloc_count;
2634 return TRUE;
2637 /* Allocate a new link_order for a section. */
2639 struct bfd_link_order *
2640 bfd_new_link_order (bfd *abfd, asection *section)
2642 bfd_size_type amt = sizeof (struct bfd_link_order);
2643 struct bfd_link_order *new_lo;
2645 new_lo = (struct bfd_link_order *) bfd_zalloc (abfd, amt);
2646 if (!new_lo)
2647 return NULL;
2649 new_lo->type = bfd_undefined_link_order;
2651 if (section->map_tail.link_order != NULL)
2652 section->map_tail.link_order->next = new_lo;
2653 else
2654 section->map_head.link_order = new_lo;
2655 section->map_tail.link_order = new_lo;
2657 return new_lo;
2660 /* Default link order processing routine. Note that we can not handle
2661 the reloc_link_order types here, since they depend upon the details
2662 of how the particular backends generates relocs. */
2664 bfd_boolean
2665 _bfd_default_link_order (bfd *abfd,
2666 struct bfd_link_info *info,
2667 asection *sec,
2668 struct bfd_link_order *link_order)
2670 switch (link_order->type)
2672 case bfd_undefined_link_order:
2673 case bfd_section_reloc_link_order:
2674 case bfd_symbol_reloc_link_order:
2675 default:
2676 abort ();
2677 case bfd_indirect_link_order:
2678 return default_indirect_link_order (abfd, info, sec, link_order,
2679 FALSE);
2680 case bfd_data_link_order:
2681 return default_data_link_order (abfd, info, sec, link_order);
2685 /* Default routine to handle a bfd_data_link_order. */
2687 static bfd_boolean
2688 default_data_link_order (bfd *abfd,
2689 struct bfd_link_info *info ATTRIBUTE_UNUSED,
2690 asection *sec,
2691 struct bfd_link_order *link_order)
2693 bfd_size_type size;
2694 size_t fill_size;
2695 bfd_byte *fill;
2696 file_ptr loc;
2697 bfd_boolean result;
2699 BFD_ASSERT ((sec->flags & SEC_HAS_CONTENTS) != 0);
2701 size = link_order->size;
2702 if (size == 0)
2703 return TRUE;
2705 fill = link_order->u.data.contents;
2706 fill_size = link_order->u.data.size;
2707 if (fill_size != 0 && fill_size < size)
2709 bfd_byte *p;
2710 fill = (bfd_byte *) bfd_malloc (size);
2711 if (fill == NULL)
2712 return FALSE;
2713 p = fill;
2714 if (fill_size == 1)
2715 memset (p, (int) link_order->u.data.contents[0], (size_t) size);
2716 else
2720 memcpy (p, link_order->u.data.contents, fill_size);
2721 p += fill_size;
2722 size -= fill_size;
2724 while (size >= fill_size);
2725 if (size != 0)
2726 memcpy (p, link_order->u.data.contents, (size_t) size);
2727 size = link_order->size;
2731 loc = link_order->offset * bfd_octets_per_byte (abfd);
2732 result = bfd_set_section_contents (abfd, sec, fill, loc, size);
2734 if (fill != link_order->u.data.contents)
2735 free (fill);
2736 return result;
2739 /* Default routine to handle a bfd_indirect_link_order. */
2741 static bfd_boolean
2742 default_indirect_link_order (bfd *output_bfd,
2743 struct bfd_link_info *info,
2744 asection *output_section,
2745 struct bfd_link_order *link_order,
2746 bfd_boolean generic_linker)
2748 asection *input_section;
2749 bfd *input_bfd;
2750 bfd_byte *contents = NULL;
2751 bfd_byte *new_contents;
2752 bfd_size_type sec_size;
2753 file_ptr loc;
2755 BFD_ASSERT ((output_section->flags & SEC_HAS_CONTENTS) != 0);
2757 input_section = link_order->u.indirect.section;
2758 input_bfd = input_section->owner;
2759 if (input_section->size == 0)
2760 return TRUE;
2762 BFD_ASSERT (input_section->output_section == output_section);
2763 BFD_ASSERT (input_section->output_offset == link_order->offset);
2764 BFD_ASSERT (input_section->size == link_order->size);
2766 if (info->relocatable
2767 && input_section->reloc_count > 0
2768 && output_section->orelocation == NULL)
2770 /* Space has not been allocated for the output relocations.
2771 This can happen when we are called by a specific backend
2772 because somebody is attempting to link together different
2773 types of object files. Handling this case correctly is
2774 difficult, and sometimes impossible. */
2775 (*_bfd_error_handler)
2776 (_("Attempt to do relocatable link with %s input and %s output"),
2777 bfd_get_target (input_bfd), bfd_get_target (output_bfd));
2778 bfd_set_error (bfd_error_wrong_format);
2779 return FALSE;
2782 if (! generic_linker)
2784 asymbol **sympp;
2785 asymbol **symppend;
2787 /* Get the canonical symbols. The generic linker will always
2788 have retrieved them by this point, but we are being called by
2789 a specific linker, presumably because we are linking
2790 different types of object files together. */
2791 if (!bfd_generic_link_read_symbols (input_bfd))
2792 return FALSE;
2794 /* Since we have been called by a specific linker, rather than
2795 the generic linker, the values of the symbols will not be
2796 right. They will be the values as seen in the input file,
2797 not the values of the final link. We need to fix them up
2798 before we can relocate the section. */
2799 sympp = _bfd_generic_link_get_symbols (input_bfd);
2800 symppend = sympp + _bfd_generic_link_get_symcount (input_bfd);
2801 for (; sympp < symppend; sympp++)
2803 asymbol *sym;
2804 struct bfd_link_hash_entry *h;
2806 sym = *sympp;
2808 if ((sym->flags & (BSF_INDIRECT
2809 | BSF_WARNING
2810 | BSF_GLOBAL
2811 | BSF_CONSTRUCTOR
2812 | BSF_WEAK)) != 0
2813 || bfd_is_und_section (bfd_get_section (sym))
2814 || bfd_is_com_section (bfd_get_section (sym))
2815 || bfd_is_ind_section (bfd_get_section (sym)))
2817 /* sym->udata may have been set by
2818 generic_link_add_symbol_list. */
2819 if (sym->udata.p != NULL)
2820 h = (struct bfd_link_hash_entry *) sym->udata.p;
2821 else if (bfd_is_und_section (bfd_get_section (sym)))
2822 h = bfd_wrapped_link_hash_lookup (output_bfd, info,
2823 bfd_asymbol_name (sym),
2824 FALSE, FALSE, TRUE);
2825 else
2826 h = bfd_link_hash_lookup (info->hash,
2827 bfd_asymbol_name (sym),
2828 FALSE, FALSE, TRUE);
2829 if (h != NULL)
2830 set_symbol_from_hash (sym, h);
2835 if ((output_section->flags & (SEC_GROUP | SEC_LINKER_CREATED)) == SEC_GROUP
2836 && input_section->size != 0)
2838 /* Group section contents are set by bfd_elf_set_group_contents. */
2839 if (!output_bfd->output_has_begun)
2841 /* FIXME: This hack ensures bfd_elf_set_group_contents is called. */
2842 if (!bfd_set_section_contents (output_bfd, output_section, "", 0, 1))
2843 goto error_return;
2845 new_contents = output_section->contents;
2846 BFD_ASSERT (new_contents != NULL);
2847 BFD_ASSERT (input_section->output_offset == 0);
2849 else
2851 /* Get and relocate the section contents. */
2852 sec_size = (input_section->rawsize > input_section->size
2853 ? input_section->rawsize
2854 : input_section->size);
2855 contents = (bfd_byte *) bfd_malloc (sec_size);
2856 if (contents == NULL && sec_size != 0)
2857 goto error_return;
2858 new_contents = (bfd_get_relocated_section_contents
2859 (output_bfd, info, link_order, contents,
2860 info->relocatable,
2861 _bfd_generic_link_get_symbols (input_bfd)));
2862 if (!new_contents)
2863 goto error_return;
2866 /* Output the section contents. */
2867 loc = input_section->output_offset * bfd_octets_per_byte (output_bfd);
2868 if (! bfd_set_section_contents (output_bfd, output_section,
2869 new_contents, loc, input_section->size))
2870 goto error_return;
2872 if (contents != NULL)
2873 free (contents);
2874 return TRUE;
2876 error_return:
2877 if (contents != NULL)
2878 free (contents);
2879 return FALSE;
2882 /* A little routine to count the number of relocs in a link_order
2883 list. */
2885 unsigned int
2886 _bfd_count_link_order_relocs (struct bfd_link_order *link_order)
2888 register unsigned int c;
2889 register struct bfd_link_order *l;
2891 c = 0;
2892 for (l = link_order; l != NULL; l = l->next)
2894 if (l->type == bfd_section_reloc_link_order
2895 || l->type == bfd_symbol_reloc_link_order)
2896 ++c;
2899 return c;
2903 FUNCTION
2904 bfd_link_split_section
2906 SYNOPSIS
2907 bfd_boolean bfd_link_split_section (bfd *abfd, asection *sec);
2909 DESCRIPTION
2910 Return nonzero if @var{sec} should be split during a
2911 reloceatable or final link.
2913 .#define bfd_link_split_section(abfd, sec) \
2914 . BFD_SEND (abfd, _bfd_link_split_section, (abfd, sec))
2919 bfd_boolean
2920 _bfd_generic_link_split_section (bfd *abfd ATTRIBUTE_UNUSED,
2921 asection *sec ATTRIBUTE_UNUSED)
2923 return FALSE;
2927 FUNCTION
2928 bfd_section_already_linked
2930 SYNOPSIS
2931 void bfd_section_already_linked (bfd *abfd, asection *sec,
2932 struct bfd_link_info *info);
2934 DESCRIPTION
2935 Check if @var{sec} has been already linked during a reloceatable
2936 or final link.
2938 .#define bfd_section_already_linked(abfd, sec, info) \
2939 . BFD_SEND (abfd, _section_already_linked, (abfd, sec, info))
2944 /* Sections marked with the SEC_LINK_ONCE flag should only be linked
2945 once into the output. This routine checks each section, and
2946 arrange to discard it if a section of the same name has already
2947 been linked. This code assumes that all relevant sections have the
2948 SEC_LINK_ONCE flag set; that is, it does not depend solely upon the
2949 section name. bfd_section_already_linked is called via
2950 bfd_map_over_sections. */
2952 /* The hash table. */
2954 static struct bfd_hash_table _bfd_section_already_linked_table;
2956 /* Support routines for the hash table used by section_already_linked,
2957 initialize the table, traverse, lookup, fill in an entry and remove
2958 the table. */
2960 void
2961 bfd_section_already_linked_table_traverse
2962 (bfd_boolean (*func) (struct bfd_section_already_linked_hash_entry *,
2963 void *), void *info)
2965 bfd_hash_traverse (&_bfd_section_already_linked_table,
2966 (bfd_boolean (*) (struct bfd_hash_entry *,
2967 void *)) func,
2968 info);
2971 struct bfd_section_already_linked_hash_entry *
2972 bfd_section_already_linked_table_lookup (const char *name)
2974 return ((struct bfd_section_already_linked_hash_entry *)
2975 bfd_hash_lookup (&_bfd_section_already_linked_table, name,
2976 TRUE, FALSE));
2979 bfd_boolean
2980 bfd_section_already_linked_table_insert
2981 (struct bfd_section_already_linked_hash_entry *already_linked_list,
2982 asection *sec)
2984 struct bfd_section_already_linked *l;
2986 /* Allocate the memory from the same obstack as the hash table is
2987 kept in. */
2988 l = (struct bfd_section_already_linked *)
2989 bfd_hash_allocate (&_bfd_section_already_linked_table, sizeof *l);
2990 if (l == NULL)
2991 return FALSE;
2992 l->sec = sec;
2993 l->next = already_linked_list->entry;
2994 already_linked_list->entry = l;
2995 return TRUE;
2998 static struct bfd_hash_entry *
2999 already_linked_newfunc (struct bfd_hash_entry *entry ATTRIBUTE_UNUSED,
3000 struct bfd_hash_table *table,
3001 const char *string ATTRIBUTE_UNUSED)
3003 struct bfd_section_already_linked_hash_entry *ret =
3004 (struct bfd_section_already_linked_hash_entry *)
3005 bfd_hash_allocate (table, sizeof *ret);
3007 if (ret == NULL)
3008 return NULL;
3010 ret->entry = NULL;
3012 return &ret->root;
3015 bfd_boolean
3016 bfd_section_already_linked_table_init (void)
3018 return bfd_hash_table_init_n (&_bfd_section_already_linked_table,
3019 already_linked_newfunc,
3020 sizeof (struct bfd_section_already_linked_hash_entry),
3021 42);
3024 void
3025 bfd_section_already_linked_table_free (void)
3027 bfd_hash_table_free (&_bfd_section_already_linked_table);
3030 /* This is used on non-ELF inputs. */
3032 void
3033 _bfd_generic_section_already_linked (bfd *abfd, asection *sec,
3034 struct bfd_link_info *info)
3036 flagword flags;
3037 const char *name;
3038 struct bfd_section_already_linked *l;
3039 struct bfd_section_already_linked_hash_entry *already_linked_list;
3041 flags = sec->flags;
3042 if ((flags & SEC_LINK_ONCE) == 0)
3043 return;
3045 /* FIXME: When doing a relocatable link, we may have trouble
3046 copying relocations in other sections that refer to local symbols
3047 in the section being discarded. Those relocations will have to
3048 be converted somehow; as of this writing I'm not sure that any of
3049 the backends handle that correctly.
3051 It is tempting to instead not discard link once sections when
3052 doing a relocatable link (technically, they should be discarded
3053 whenever we are building constructors). However, that fails,
3054 because the linker winds up combining all the link once sections
3055 into a single large link once section, which defeats the purpose
3056 of having link once sections in the first place. */
3058 name = bfd_get_section_name (abfd, sec);
3060 already_linked_list = bfd_section_already_linked_table_lookup (name);
3062 for (l = already_linked_list->entry; l != NULL; l = l->next)
3064 bfd_boolean skip = FALSE;
3065 struct coff_comdat_info *s_comdat
3066 = bfd_coff_get_comdat_section (abfd, sec);
3067 struct coff_comdat_info *l_comdat
3068 = bfd_coff_get_comdat_section (l->sec->owner, l->sec);
3070 /* We may have 3 different sections on the list: group section,
3071 comdat section and linkonce section. SEC may be a linkonce or
3072 comdat section. We always ignore group section. For non-COFF
3073 inputs, we also ignore comdat section.
3075 FIXME: Is that safe to match a linkonce section with a comdat
3076 section for COFF inputs? */
3077 if ((l->sec->flags & SEC_GROUP) != 0)
3078 skip = TRUE;
3079 else if (bfd_get_flavour (abfd) == bfd_target_coff_flavour)
3081 if (s_comdat != NULL
3082 && l_comdat != NULL
3083 && strcmp (s_comdat->name, l_comdat->name) != 0)
3084 skip = TRUE;
3086 else if (l_comdat != NULL)
3087 skip = TRUE;
3089 if (!skip)
3091 /* The section has already been linked. See if we should
3092 issue a warning. */
3093 switch (flags & SEC_LINK_DUPLICATES)
3095 default:
3096 abort ();
3098 case SEC_LINK_DUPLICATES_DISCARD:
3099 break;
3101 case SEC_LINK_DUPLICATES_ONE_ONLY:
3102 (*_bfd_error_handler)
3103 (_("%B: warning: ignoring duplicate section `%A'\n"),
3104 abfd, sec);
3105 break;
3107 case SEC_LINK_DUPLICATES_SAME_CONTENTS:
3108 /* FIXME: We should really dig out the contents of both
3109 sections and memcmp them. The COFF/PE spec says that
3110 the Microsoft linker does not implement this
3111 correctly, so I'm not going to bother doing it
3112 either. */
3113 /* Fall through. */
3114 case SEC_LINK_DUPLICATES_SAME_SIZE:
3115 if (sec->size != l->sec->size)
3116 (*_bfd_error_handler)
3117 (_("%B: warning: duplicate section `%A' has different size\n"),
3118 abfd, sec);
3119 break;
3122 /* Set the output_section field so that lang_add_section
3123 does not create a lang_input_section structure for this
3124 section. Since there might be a symbol in the section
3125 being discarded, we must retain a pointer to the section
3126 which we are really going to use. */
3127 sec->output_section = bfd_abs_section_ptr;
3128 sec->kept_section = l->sec;
3130 return;
3134 /* This is the first section with this name. Record it. */
3135 if (! bfd_section_already_linked_table_insert (already_linked_list, sec))
3136 info->callbacks->einfo (_("%F%P: already_linked_table: %E\n"));
3139 /* Convert symbols in excluded output sections to use a kept section. */
3141 static bfd_boolean
3142 fix_syms (struct bfd_link_hash_entry *h, void *data)
3144 bfd *obfd = (bfd *) data;
3146 if (h->type == bfd_link_hash_warning)
3147 h = h->u.i.link;
3149 if (h->type == bfd_link_hash_defined
3150 || h->type == bfd_link_hash_defweak)
3152 asection *s = h->u.def.section;
3153 if (s != NULL
3154 && s->output_section != NULL
3155 && (s->output_section->flags & SEC_EXCLUDE) != 0
3156 && bfd_section_removed_from_list (obfd, s->output_section))
3158 asection *op, *op1;
3160 h->u.def.value += s->output_offset + s->output_section->vma;
3162 /* Find preceding kept section. */
3163 for (op1 = s->output_section->prev; op1 != NULL; op1 = op1->prev)
3164 if ((op1->flags & SEC_EXCLUDE) == 0
3165 && !bfd_section_removed_from_list (obfd, op1))
3166 break;
3168 /* Find following kept section. Start at prev->next because
3169 other sections may have been added after S was removed. */
3170 if (s->output_section->prev != NULL)
3171 op = s->output_section->prev->next;
3172 else
3173 op = s->output_section->owner->sections;
3174 for (; op != NULL; op = op->next)
3175 if ((op->flags & SEC_EXCLUDE) == 0
3176 && !bfd_section_removed_from_list (obfd, op))
3177 break;
3179 /* Choose better of two sections, based on flags. The idea
3180 is to choose a section that will be in the same segment
3181 as S would have been if it was kept. */
3182 if (op1 == NULL)
3184 if (op == NULL)
3185 op = bfd_abs_section_ptr;
3187 else if (op == NULL)
3188 op = op1;
3189 else if (((op1->flags ^ op->flags)
3190 & (SEC_ALLOC | SEC_THREAD_LOCAL | SEC_LOAD)) != 0)
3192 if (((op->flags ^ s->flags)
3193 & (SEC_ALLOC | SEC_THREAD_LOCAL)) != 0
3194 /* We prefer to choose a loaded section. Section S
3195 doesn't have SEC_LOAD set (it being excluded, that
3196 part of the flag processing didn't happen) so we
3197 can't compare that flag to those of OP and OP1. */
3198 || ((op1->flags & SEC_LOAD) != 0
3199 && (op->flags & SEC_LOAD) == 0))
3200 op = op1;
3202 else if (((op1->flags ^ op->flags) & SEC_READONLY) != 0)
3204 if (((op->flags ^ s->flags) & SEC_READONLY) != 0)
3205 op = op1;
3207 else if (((op1->flags ^ op->flags) & SEC_CODE) != 0)
3209 if (((op->flags ^ s->flags) & SEC_CODE) != 0)
3210 op = op1;
3212 else
3214 /* Flags we care about are the same. Prefer the following
3215 section if that will result in a positive valued sym. */
3216 if (h->u.def.value < op->vma)
3217 op = op1;
3220 h->u.def.value -= op->vma;
3221 h->u.def.section = op;
3225 return TRUE;
3228 void
3229 _bfd_fix_excluded_sec_syms (bfd *obfd, struct bfd_link_info *info)
3231 bfd_link_hash_traverse (info->hash, fix_syms, obfd);
3235 FUNCTION
3236 bfd_generic_define_common_symbol
3238 SYNOPSIS
3239 bfd_boolean bfd_generic_define_common_symbol
3240 (bfd *output_bfd, struct bfd_link_info *info,
3241 struct bfd_link_hash_entry *h);
3243 DESCRIPTION
3244 Convert common symbol @var{h} into a defined symbol.
3245 Return TRUE on success and FALSE on failure.
3247 .#define bfd_define_common_symbol(output_bfd, info, h) \
3248 . BFD_SEND (output_bfd, _bfd_define_common_symbol, (output_bfd, info, h))
3252 bfd_boolean
3253 bfd_generic_define_common_symbol (bfd *output_bfd,
3254 struct bfd_link_info *info ATTRIBUTE_UNUSED,
3255 struct bfd_link_hash_entry *h)
3257 unsigned int power_of_two;
3258 bfd_vma alignment, size;
3259 asection *section;
3261 BFD_ASSERT (h != NULL && h->type == bfd_link_hash_common);
3263 size = h->u.c.size;
3264 power_of_two = h->u.c.p->alignment_power;
3265 section = h->u.c.p->section;
3267 /* Increase the size of the section to align the common symbol.
3268 The alignment must be a power of two. */
3269 alignment = bfd_octets_per_byte (output_bfd) << power_of_two;
3270 BFD_ASSERT (alignment != 0 && (alignment & -alignment) == alignment);
3271 section->size += alignment - 1;
3272 section->size &= -alignment;
3274 /* Adjust the section's overall alignment if necessary. */
3275 if (power_of_two > section->alignment_power)
3276 section->alignment_power = power_of_two;
3278 /* Change the symbol from common to defined. */
3279 h->type = bfd_link_hash_defined;
3280 h->u.def.section = section;
3281 h->u.def.value = section->size;
3283 /* Increase the size of the section. */
3284 section->size += size;
3286 /* Make sure the section is allocated in memory, and make sure that
3287 it is no longer a common section. */
3288 section->flags |= SEC_ALLOC;
3289 section->flags &= ~SEC_IS_COMMON;
3290 return TRUE;
3294 FUNCTION
3295 bfd_find_version_for_sym
3297 SYNOPSIS
3298 struct bfd_elf_version_tree * bfd_find_version_for_sym
3299 (struct bfd_elf_version_tree *verdefs,
3300 const char *sym_name, bfd_boolean *hide);
3302 DESCRIPTION
3303 Search an elf version script tree for symbol versioning
3304 info and export / don't-export status for a given symbol.
3305 Return non-NULL on success and NULL on failure; also sets
3306 the output @samp{hide} boolean parameter.
3310 struct bfd_elf_version_tree *
3311 bfd_find_version_for_sym (struct bfd_elf_version_tree *verdefs,
3312 const char *sym_name,
3313 bfd_boolean *hide)
3315 struct bfd_elf_version_tree *t;
3316 struct bfd_elf_version_tree *local_ver, *global_ver, *exist_ver;
3317 struct bfd_elf_version_tree *star_local_ver, *star_global_ver;
3319 local_ver = NULL;
3320 global_ver = NULL;
3321 star_local_ver = NULL;
3322 star_global_ver = NULL;
3323 exist_ver = NULL;
3324 for (t = verdefs; t != NULL; t = t->next)
3326 if (t->globals.list != NULL)
3328 struct bfd_elf_version_expr *d = NULL;
3330 while ((d = (*t->match) (&t->globals, d, sym_name)) != NULL)
3332 if (d->literal || strcmp (d->pattern, "*") != 0)
3333 global_ver = t;
3334 else
3335 star_global_ver = t;
3336 if (d->symver)
3337 exist_ver = t;
3338 d->script = 1;
3339 /* If the match is a wildcard pattern, keep looking for
3340 a more explicit, perhaps even local, match. */
3341 if (d->literal)
3342 break;
3345 if (d != NULL)
3346 break;
3349 if (t->locals.list != NULL)
3351 struct bfd_elf_version_expr *d = NULL;
3353 while ((d = (*t->match) (&t->locals, d, sym_name)) != NULL)
3355 if (d->literal || strcmp (d->pattern, "*") != 0)
3356 local_ver = t;
3357 else
3358 star_local_ver = t;
3359 /* If the match is a wildcard pattern, keep looking for
3360 a more explicit, perhaps even global, match. */
3361 if (d->literal)
3363 /* An exact match overrides a global wildcard. */
3364 global_ver = NULL;
3365 star_global_ver = NULL;
3366 break;
3370 if (d != NULL)
3371 break;
3375 if (global_ver == NULL && local_ver == NULL)
3376 global_ver = star_global_ver;
3378 if (global_ver != NULL)
3380 /* If we already have a versioned symbol that matches the
3381 node for this symbol, then we don't want to create a
3382 duplicate from the unversioned symbol. Instead hide the
3383 unversioned symbol. */
3384 *hide = exist_ver == global_ver;
3385 return global_ver;
3388 if (local_ver == NULL)
3389 local_ver = star_local_ver;
3391 if (local_ver != NULL)
3393 *hide = TRUE;
3394 return local_ver;
3397 return NULL;