aboutsummaryrefslogtreecommitdiff
path: root/ld/ldmain.c
blob: 55049d71c46049740f37948e52155936a267a045 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
/* Main program of GNU linker.
   Copyright (C) 1991, 92, 93, 94 Free Software Foundation, Inc.
   Written by Steve Chamberlain steve@cygnus.com

This file is part of GLD, the Gnu Linker.

GLD is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GLD is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GLD; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */


#include "bfd.h"
#include "sysdep.h"
#include <stdio.h>
#include "libiberty.h"
#include "progress.h"
#include "bfdlink.h"

#include "config.h"
#include "ld.h"
#include "ldmain.h"
#include "ldmisc.h"
#include "ldwrite.h"
#include "ldgram.h"
#include "ldexp.h"
#include "ldlang.h"
#include "ldemul.h"
#include "ldlex.h"
#include "ldfile.h"
#include "ldctor.h"

/* Somewhere above, sys/stat.h got included . . . . */
#if !defined(S_ISDIR) && defined(S_IFDIR)
#define	S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
#endif

#include <string.h>

/* Use sbrk() except on specific OS types */
#if !defined(__amigados__) && !defined(WINDOWS_NT)
#define HAVE_SBRK
#endif

static char *get_emulation PARAMS ((int, char **));
static void set_scripts_dir PARAMS ((void));

/* EXPORTS */

char *default_target;
const char *output_filename = "a.out";

/* Name this program was invoked by.  */
char *program_name;

/* The file that we're creating */
bfd *output_bfd = 0;

/* Set by -G argument, for MIPS ECOFF target.  */
int g_switch_value = 8;

/* Nonzero means print names of input files as processed.  */
boolean trace_files;

/* Nonzero means same, but note open failures, too.  */
boolean trace_file_tries;

/* Nonzero means version number was printed, so exit successfully
   instead of complaining if no input files are given.  */
boolean version_printed;

/* Nonzero means link in every member of an archive.  */
boolean whole_archive;

args_type command_line;

ld_config_type config;

static boolean check_for_scripts_dir PARAMS ((char *dir));
static boolean add_archive_element PARAMS ((struct bfd_link_info *, bfd *,
					    const char *));
static boolean multiple_definition PARAMS ((struct bfd_link_info *,
					    const char *,
					    bfd *, asection *, bfd_vma,
					    bfd *, asection *, bfd_vma));
static boolean multiple_common PARAMS ((struct bfd_link_info *,
					const char *, bfd *,
					enum bfd_link_hash_type, bfd_vma,
					bfd *, enum bfd_link_hash_type,
					bfd_vma));
static boolean add_to_set PARAMS ((struct bfd_link_info *,
				   struct bfd_link_hash_entry *,
				   bfd_reloc_code_real_type,
				   bfd *, asection *, bfd_vma));
static boolean constructor_callback PARAMS ((struct bfd_link_info *,
					     boolean constructor,
					     const char *name,
					     bfd *, asection *, bfd_vma));
static boolean warning_callback PARAMS ((struct bfd_link_info *,
					 const char *));
static boolean undefined_symbol PARAMS ((struct bfd_link_info *,
					 const char *, bfd *,
					 asection *, bfd_vma));
static boolean reloc_overflow PARAMS ((struct bfd_link_info *, const char *,
				       const char *, bfd_vma,
				       bfd *, asection *, bfd_vma));
static boolean reloc_dangerous PARAMS ((struct bfd_link_info *, const char *,
					bfd *, asection *, bfd_vma));
static boolean unattached_reloc PARAMS ((struct bfd_link_info *,
					 const char *, bfd *, asection *,
					 bfd_vma));
static boolean notice_ysym PARAMS ((struct bfd_link_info *, const char *,
				    bfd *, asection *, bfd_vma));

static struct bfd_link_callbacks link_callbacks =
{
  add_archive_element,
  multiple_definition,
  multiple_common,
  add_to_set,
  constructor_callback,
  warning_callback,
  undefined_symbol,
  reloc_overflow,
  reloc_dangerous,
  unattached_reloc,
  notice_ysym
};

struct bfd_link_info link_info;

static void
remove_output ()
{
  if (output_filename) 
    {
      if (output_bfd && output_bfd->iostream)
	fclose((FILE *)(output_bfd->iostream));
      if (delete_output_file_on_failure)
	unlink (output_filename);
    }
}

int
main (argc, argv)
     int argc;
     char **argv;
{
  char *emulation;
  long start_time = get_run_time ();

  program_name = argv[0];
  xmalloc_set_program_name (program_name);

  START_PROGRESS (program_name, 0);

  bfd_init ();

  xatexit (remove_output);

  /* Initialize the data about options.  */
  trace_files = trace_file_tries = version_printed = false;
  whole_archive = false;
  config.traditional_format = false;
  config.build_constructors = true;
  config.dynamic_link = false;
  command_line.force_common_definition = false;
  command_line.interpreter = NULL;
  command_line.rpath = NULL;

  link_info.callbacks = &link_callbacks;
  link_info.relocateable = false;
  link_info.shared = false;
  link_info.symbolic = false;
  link_info.strip = strip_none;
  link_info.discard = discard_none;
  link_info.lprefix_len = 1;
  link_info.lprefix = "L";
  link_info.keep_memory = true;
  link_info.input_bfds = NULL;
  link_info.create_object_symbols_section = NULL;
  link_info.hash = NULL;
  link_info.keep_hash = NULL;
  link_info.notice_hash = NULL;
  link_info.subsystem = console;
  link_info.stack_heap_parameters.stack_defined = false;
  link_info.stack_heap_parameters.heap_defined  = false;
  link_info.stack_heap_parameters.stack_reserve = 0;
  link_info.stack_heap_parameters.stack_commit  = 0;
  link_info.stack_heap_parameters.heap_reserve  = 0;
  link_info.stack_heap_parameters.heap_commit   = 0;


  ldfile_add_arch ("");

  config.make_executable = true;
  force_make_executable = false;
  config.magic_demand_paged = true;
  config.text_read_only = true;
  config.make_executable = true;

  emulation = get_emulation (argc, argv);
  ldemul_choose_mode (emulation);
  default_target = ldemul_choose_target ();
  lang_init ();
  ldemul_before_parse ();
  lang_has_input_file = false;
  parse_args (argc, argv);

  if (link_info.relocateable)
    {
      if (command_line.relax)
	einfo ("%P%F: -relax and -r may not be used together\n");
      if (link_info.shared)
	einfo ("%P%F: -r and -shared may not be used together\n");
    }

  /* Treat ld -r -s as ld -r -S -x (i.e., strip all local symbols).  I
     don't see how else this can be handled, since in this case we
     must preserve all externally visible symbols.  */
  if (link_info.relocateable && link_info.strip == strip_all)
    {
      link_info.strip = strip_debugger;
      if (link_info.discard == discard_none)
	link_info.discard = discard_all;
    }

  /* This essentially adds another -L directory so this must be done after
     the -L's in argv have been processed.  */
  set_scripts_dir ();

  if (had_script == false)
    {
      /* Read the emulation's appropriate default script.  */
      int isfile;
      char *s = ldemul_get_script (&isfile);

      if (isfile)
	ldfile_open_command_file (s);
      else
	{
	  if (trace_file_tries)
	    {
	      info_msg ("using internal linker script:\n");
	      info_msg ("==================================================\n");
	      info_msg (s);
	      info_msg ("\n==================================================\n");
	    }
	  lex_redirect (s);
	}
      parser_input = input_script;
      yyparse ();
    }

  lang_final ();

  if (lang_has_input_file == false)
    {
      if (version_printed)
	xexit (0);
      einfo ("%P%F: no input files\n");
    }

  if (trace_files)
    {
      info_msg ("%P: mode %s\n", emulation);
    }

  ldemul_after_parse ();


  if (config.map_filename)
    {
      if (strcmp (config.map_filename, "-") == 0)
	{
	  config.map_file = stdout;
	}
      else
	{
	  config.map_file = fopen (config.map_filename, FOPEN_WT);
	  if (config.map_file == (FILE *) NULL)
	    {
	      bfd_set_error (bfd_error_system_call);
	      einfo ("%P%F: cannot open map file %s: %E\n",
		     config.map_filename);
	    }
	}
    }


  lang_process ();

  /* Print error messages for any missing symbols, for any warning
     symbols, and possibly multiple definitions */


  if (config.text_read_only)
    {
      /* Look for a text section and mark the readonly attribute in it */
      asection *found = bfd_get_section_by_name (output_bfd, ".text");

      if (found != (asection *) NULL)
	{
	  found->flags |= SEC_READONLY;
	}
    }

  if (link_info.relocateable)
    output_bfd->flags &= ~EXEC_P;
  else
    output_bfd->flags |= EXEC_P;

  ldwrite ();

  /* Even if we're producing relocateable output, some non-fatal errors should
     be reported in the exit status.  (What non-fatal errors, if any, do we
     want to ignore for relocateable output?)  */

  if (config.make_executable == false && force_make_executable == false)
    {
      if (trace_files == true)
	{
	  einfo ("%P: link errors found, deleting executable `%s'\n",
		 output_filename);
	}

      if (output_bfd->iostream)
	fclose ((FILE *) (output_bfd->iostream));

      unlink (output_filename);
      xexit (1);
    }
  else
    {
      if (! bfd_close (output_bfd))
	einfo ("%F%B: final close failed: %E\n", output_bfd);
    }

  END_PROGRESS (program_name);

  if (config.stats)
    {
      extern char **environ;
#ifdef HAVE_SBRK
      char *lim = (char *) sbrk (0);
#endif
      long run_time = get_run_time () - start_time;

      fprintf (stderr, "%s: total time in link: %ld.%06ld\n",
	       program_name, run_time / 1000000, run_time % 1000000);
#ifdef HAVE_SBRK
      fprintf (stderr, "%s: data size %ld\n", program_name,
	       (long) (lim - (char *) &environ));
#endif
    }

  /* Prevent remove_output from doing anything, after a successful link.  */
  output_filename = NULL;

  xexit (0);
  return 0;
}

/* We need to find any explicitly given emulation in order to initialize the
   state that's needed by the lex&yacc argument parser (parse_args).  */

static char *
get_emulation (argc, argv)
     int argc;
     char **argv;
{
  char *emulation;
  int i;

  emulation = (char *) getenv (EMULATION_ENVIRON);
  if (emulation == NULL)
    emulation = DEFAULT_EMULATION;

  for (i = 1; i < argc; i++)
    {
      if (!strncmp (argv[i], "-m", 2))
	{
	  if (argv[i][2] == '\0')
	    {
	      /* -m EMUL */
	      if (i < argc - 1)
		{
		  emulation = argv[i + 1];
		  i++;
		}
	      else
		{
		  einfo("%P%F: missing argument to -m\n");
		}
	    }
	  else if (strcmp (argv[i], "-mips1") == 0
		   || strcmp (argv[i], "-mips2") == 0
		   || strcmp (argv[i], "-mips3") == 0)
	    {
	      /* FIXME: The arguments -mips1, -mips2 and -mips3 are
		 passed to the linker by some MIPS compilers.  They
		 generally tell the linker to use a slightly different
		 library path.  Perhaps someday these should be
		 implemented as emulations; until then, we just ignore
		 the arguments and hope that nobody ever creates
		 emulations named ips1, ips2 or ips3.  */
	    }
	  else if (strcmp (argv[i], "-m486") == 0)
	    {
	      /* FIXME: The argument -m486 is passed to the linker on
		 some Linux systems.  Hope that nobody creates an
		 emulation named 486.  */
	    }
	  else
	    {
	      /* -mEMUL */
	      emulation = &argv[i][2];
	    }
	}
    }

  return emulation;
}

/* If directory DIR contains an "ldscripts" subdirectory,
   add DIR to the library search path and return true,
   else return false.  */

static boolean
check_for_scripts_dir (dir)
     char *dir;
{
  size_t dirlen;
  char *buf;
  struct stat s;
  boolean res;

  dirlen = strlen (dir);
  /* sizeof counts the terminating NUL.  */
  buf = (char *) xmalloc (dirlen + sizeof("/ldscripts"));
  sprintf (buf, "%s/ldscripts", dir);

  res = stat (buf, &s) == 0 && S_ISDIR (s.st_mode);
  free (buf);
  if (res)
    ldfile_add_library_path (dir, false);
  return res;
}

/* Set the default directory for finding script files.
   Libraries will be searched for here too, but that's ok.
   We look for the "ldscripts" directory in:

   SCRIPTDIR (passed from Makefile)
   the dir where this program is (for using it from the build tree)
   the dir where this program is/../lib (for installing the tool suite elsewhere) */

static void
set_scripts_dir ()
{
  char *end, *dir;
  size_t dirlen;

  if (check_for_scripts_dir (SCRIPTDIR))
    return;			/* We've been installed normally.  */

  /* Look for "ldscripts" in the dir where our binary is.  */
  end = strrchr (program_name, '/');
  if (end)
    {
      dirlen = end - program_name;
      /* Make a copy of program_name in dir.
	 Leave room for later "/../lib".  */
      dir = (char *) xmalloc (dirlen + 8);
      strncpy (dir, program_name, dirlen);
      dir[dirlen] = '\0';
    }
  else
    {
      dirlen = 1;
      dir = (char *) xmalloc (dirlen + 8);
      strcpy (dir, ".");
    }

  if (check_for_scripts_dir (dir))
    return;			/* Don't free dir.  */

  /* Look for "ldscripts" in <the dir where our binary is>/../lib.  */
  strcpy (dir + dirlen, "/../lib");
  if (check_for_scripts_dir (dir))
    return;

  free (dir);			/* Well, we tried.  */
}

void
add_ysym (name)
     const char *name;
{
  if (link_info.notice_hash == (struct bfd_hash_table *) NULL)
    {
      link_info.notice_hash = ((struct bfd_hash_table *)
			       xmalloc (sizeof (struct bfd_hash_table)));
      if (! bfd_hash_table_init_n (link_info.notice_hash,
				   bfd_hash_newfunc,
				   61))
	einfo ("%P%F: bfd_hash_table_init failed: %E\n");
    }      

  if (bfd_hash_lookup (link_info.notice_hash, name, true, true)
      == (struct bfd_hash_entry *) NULL)
    einfo ("%P%F: bfd_hash_lookup failed: %E\n");
}

/* Handle the -retain-symbols-file option.  */

void
add_keepsyms_file (filename)
     const char *filename;
{
  FILE *file;
  char *buf;
  size_t bufsize;
  int c;

  if (link_info.strip == strip_some)
    einfo ("%X%P: error: duplicate retain-symbols-file\n");

  file = fopen (filename, "r");
  if (file == (FILE *) NULL)
    {
      bfd_set_error (bfd_error_system_call);
      einfo ("%X%P: %s: %E", filename);
      return;
    }

  link_info.keep_hash = ((struct bfd_hash_table *)
			 xmalloc (sizeof (struct bfd_hash_table)));
  if (! bfd_hash_table_init (link_info.keep_hash, bfd_hash_newfunc))
    einfo ("%P%F: bfd_hash_table_init failed: %E\n");

  bufsize = 100;
  buf = (char *) xmalloc (bufsize);

  c = getc (file);
  while (c != EOF)
    {
      while (isspace (c))
	c = getc (file);

      if (c != EOF)
	{
	  size_t len = 0;

	  while (! isspace (c) && c != EOF)
	    {
	      buf[len] = c;
	      ++len;
	      if (len >= bufsize)
		{
		  bufsize *= 2;
		  buf = xrealloc (buf, bufsize);
		}
	      c = getc (file);
	    }

	  buf[len] = '\0';

	  if (bfd_hash_lookup (link_info.keep_hash, buf, true, true)
	      == (struct bfd_hash_entry *) NULL)
	    einfo ("%P%F: bfd_hash_lookup for insertion failed: %E");
	}
    }

  if (link_info.strip != strip_none)
    einfo ("%P: `-retain-symbols-file' overrides `-s' and `-S'\n");

  link_info.strip = strip_some;
}

/* Callbacks from the BFD linker routines.  */

/* This is called when BFD has decided to include an archive member in
   a link.  */

/*ARGSUSED*/
static boolean
add_archive_element (info, abfd, name)
     struct bfd_link_info *info;
     bfd *abfd;
     const char *name;
{
  lang_input_statement_type *input;

  input = ((lang_input_statement_type *)
	   xmalloc ((bfd_size_type) sizeof (lang_input_statement_type)));
  input->filename = abfd->filename;
  input->local_sym_name = abfd->filename;
  input->the_bfd = abfd;
  input->asymbols = NULL;
  input->next = NULL;
  input->just_syms_flag = false;
  input->loaded = false;
  input->search_dirs_flag = false;

  /* FIXME: The following fields are not set: header.next,
     header.type, closed, passive_position, symbol_count,
     next_real_file, is_archive, target, real, common_section,
     common_output_section, complained.  This bit of code is from the
     old decode_library_subfile function.  I don't know whether any of
     those fields matters.  */

  ldlang_add_file (input);

  if (config.map_file != (FILE *) NULL)
    minfo ("%s needed due to %T\n", abfd->filename, name);

  if (trace_files || trace_file_tries)
    info_msg ("%I\n", input);

  return true;
}

/* This is called when BFD has discovered a symbol which is defined
   multiple times.  */

/*ARGSUSED*/
static boolean
multiple_definition (info, name, obfd, osec, oval, nbfd, nsec, nval)
     struct bfd_link_info *info;
     const char *name;
     bfd *obfd;
     asection *osec;
     bfd_vma oval;
     bfd *nbfd;
     asection *nsec;
     bfd_vma nval;
{
  einfo ("%X%C: multiple definition of `%T'\n",
	 nbfd, nsec, nval, name);
  if (obfd != (bfd *) NULL)
    einfo ("%D: first defined here\n", obfd, osec, oval);
  return true;
}

/* This is called when there is a definition of a common symbol, or
   when a common symbol is found for a symbol that is already defined,
   or when two common symbols are found.  We only do something if
   -warn-common was used.  */

/*ARGSUSED*/
static boolean
multiple_common (info, name, obfd, otype, osize, nbfd, ntype, nsize)
     struct bfd_link_info *info;
     const char *name;
     bfd *obfd;
     enum bfd_link_hash_type otype;
     bfd_vma osize;
     bfd *nbfd;
     enum bfd_link_hash_type ntype;
     bfd_vma nsize;
{
  if (! config.warn_common)
    return true;

  if (ntype == bfd_link_hash_defined
      || ntype == bfd_link_hash_defweak
      || ntype == bfd_link_hash_indirect)
    {
      ASSERT (otype == bfd_link_hash_common);
      einfo ("%B: warning: definition of `%T' overriding common\n",
	     nbfd, name);
      if (obfd != NULL)
	einfo ("%B: warning: common is here\n", obfd);
    }
  else if (otype == bfd_link_hash_defined
	   || otype == bfd_link_hash_defweak
	   || otype == bfd_link_hash_indirect)
    {
      ASSERT (ntype == bfd_link_hash_common);
      einfo ("%B: warning: common of `%T' overridden by definition\n",
	     nbfd, name);
      if (obfd != NULL)
	einfo ("%B: warning: defined here\n", obfd);
    }
  else
    {
      ASSERT (otype == bfd_link_hash_common && ntype == bfd_link_hash_common);
      if (osize > nsize)
	{
	  einfo ("%B: warning: common of `%T' overridden by larger common\n",
		 nbfd, name);
	  if (obfd != NULL)
	    einfo ("%B: warning: larger common is here\n", obfd);
	}
      else if (nsize > osize)
	{
	  einfo ("%B: warning: common of `%T' overriding smaller common\n",
		 nbfd, name);
	  if (obfd != NULL)
	    einfo ("%B: warning: smaller common is here\n", obfd);
	}
      else
	{
	  einfo ("%B: warning: multiple common of `%T'\n", nbfd, name);
	  if (obfd != NULL)
	    einfo ("%B: warning: previous common is here\n", obfd);
	}
    }

  return true;
}

/* This is called when BFD has discovered a set element.  H is the
   entry in the linker hash table for the set.  SECTION and VALUE
   represent a value which should be added to the set.  */

/*ARGSUSED*/
static boolean
add_to_set (info, h, reloc, abfd, section, value)
     struct bfd_link_info *info;
     struct bfd_link_hash_entry *h;
     bfd_reloc_code_real_type reloc;
     bfd *abfd;
     asection *section;
     bfd_vma value;
{
  if (! config.build_constructors)
    return true;

  ldctor_add_set_entry (h, reloc, section, value);

  if (h->type == bfd_link_hash_new)
    {
      h->type = bfd_link_hash_undefined;
      h->u.undef.abfd = abfd;
      /* We don't call bfd_link_add_undef to add this to the list of
	 undefined symbols because we are going to define it
	 ourselves.  */
    }

  return true;
}

/* This is called when BFD has discovered a constructor.  This is only
   called for some object file formats--those which do not handle
   constructors in some more clever fashion.  This is similar to
   adding an element to a set, but less general.  */

static boolean
constructor_callback (info, constructor, name, abfd, section, value)
     struct bfd_link_info *info;
     boolean constructor;
     const char *name;
     bfd *abfd;
     asection *section;
     bfd_vma value;
{
  char *set_name;
  char *s;
  struct bfd_link_hash_entry *h;

  if (! config.build_constructors)
    return true;

  /* Ensure that BFD_RELOC_CTOR exists now, so that we can give a
     useful error message.  */
  if (bfd_reloc_type_lookup (output_bfd, BFD_RELOC_CTOR) == NULL)
    einfo ("%P%F: BFD backend error: BFD_RELOC_CTOR unsupported");

  set_name = (char *) alloca (1 + sizeof "__CTOR_LIST__");
  s = set_name;
  if (bfd_get_symbol_leading_char (abfd) != '\0')
    *s++ = bfd_get_symbol_leading_char (abfd);
  if (constructor)
    strcpy (s, "__CTOR_LIST__");
  else
    strcpy (s, "__DTOR_LIST__");

  if (config.map_file != (FILE *) NULL)
    fprintf (config.map_file,
	     "Adding %s to constructor/destructor set %s\n", name, set_name);

  h = bfd_link_hash_lookup (info->hash, set_name, true, true, true);
  if (h == (struct bfd_link_hash_entry *) NULL)
    einfo ("%P%F: bfd_link_hash_lookup failed: %E");
  if (h->type == bfd_link_hash_new)
    {
      h->type = bfd_link_hash_undefined;
      h->u.undef.abfd = abfd;
      /* We don't call bfd_link_add_undef to add this to the list of
	 undefined symbols because we are going to define it
	 ourselves.  */
    }

  ldctor_add_set_entry (h, BFD_RELOC_CTOR, section, value);
  return true;
}

/* This is called when there is a reference to a warning symbol.  */

/*ARGSUSED*/
static boolean
warning_callback (info, warning)
     struct bfd_link_info *info;
     const char *warning;
{
  einfo ("%P: %s\n", warning);
  return true;
}

/* This is called when an undefined symbol is found.  */

/*ARGSUSED*/
static boolean
undefined_symbol (info, name, abfd, section, address)
     struct bfd_link_info *info;
     const char *name;
     bfd *abfd;
     asection *section;
     bfd_vma address;
{
  static char *error_name;
  static unsigned int error_count;

#define MAX_ERRORS_IN_A_ROW 5

  if (config.warn_once)
    {
      static struct bfd_hash_table *hash;

      /* Only warn once about a particular undefined symbol.  */

      if (hash == NULL)
	{
	  hash = ((struct bfd_hash_table *)
		  xmalloc (sizeof (struct bfd_hash_table)));
	  if (! bfd_hash_table_init (hash, bfd_hash_newfunc))
	    einfo ("%F%P: bfd_hash_table_init failed: %E\n");
	}

      if (bfd_hash_lookup (hash, name, false, false) != NULL)
	return true;

      if (bfd_hash_lookup (hash, name, true, true) == NULL)
	einfo ("%F%P: bfd_hash_lookup failed: %E\n");
    }

  /* We never print more than a reasonable number of errors in a row
     for a single symbol.  */
  if (error_name != (char *) NULL
      && strcmp (name, error_name) == 0)
    ++error_count;
  else
    {
      error_count = 0;
      if (error_name != (char *) NULL)
	free (error_name);
      error_name = buystring (name);
    }

  if (section != NULL)
    {
      if (error_count < MAX_ERRORS_IN_A_ROW)
	einfo ("%X%C: undefined reference to `%T'\n",
	       abfd, section, address, name);
      else if (error_count == MAX_ERRORS_IN_A_ROW)
	einfo ("%D: more undefined references to `%T' follow\n",
	       abfd, section, address, name);
    }
  else
    {
      if (error_count < MAX_ERRORS_IN_A_ROW)
	einfo ("%X%B: undefined reference to `%T'\n",
	       abfd, name);
      else if (error_count == MAX_ERRORS_IN_A_ROW)
	einfo ("%B: more undefined references to `%T' follow\n",
	       abfd, name);
    }

  return true;
}

/* This is called when a reloc overflows.  */

/*ARGSUSED*/
static boolean
reloc_overflow (info, name, reloc_name, addend, abfd, section, address)
     struct bfd_link_info *info;
     const char *name;
     const char *reloc_name;
     bfd_vma addend;
     bfd *abfd;
     asection *section;
     bfd_vma address;
{
  if (abfd == (bfd *) NULL)
    einfo ("%P%X: generated");
  else
    einfo ("%X%C:", abfd, section, address);
  einfo (" relocation truncated to fit: %s %T", reloc_name, name);
  if (addend != 0)
    einfo ("+%v", addend);
  einfo ("\n");
  return true;
}

/* This is called when a dangerous relocation is made.  */

/*ARGSUSED*/
static boolean
reloc_dangerous (info, message, abfd, section, address)
     struct bfd_link_info *info;
     const char *message;
     bfd *abfd;
     asection *section;
     bfd_vma address;
{
  if (abfd == (bfd *) NULL)
    einfo ("%P%X: generated");
  else
    einfo ("%X%C:", abfd, section, address);
  einfo ("dangerous relocation: %s\n", message);
  return true;
}

/* This is called when a reloc is being generated attached to a symbol
   that is not being output.  */

/*ARGSUSED*/
static boolean
unattached_reloc (info, name, abfd, section, address)
     struct bfd_link_info *info;
     const char *name;
     bfd *abfd;
     asection *section;
     bfd_vma address;
{
  if (abfd == (bfd *) NULL)
    einfo ("%P%X: generated");
  else
    einfo ("%X%C:", abfd, section, address);
  einfo (" reloc refers to symbol `%T' which is not being output\n", name);
  return true;
}

/* This is called when a symbol in notice_hash is found.  Symbols are
   put in notice_hash using the -y option.  */

/*ARGSUSED*/
static boolean
notice_ysym (info, name, abfd, section, value)
     struct bfd_link_info *info;
     const char *name;
     bfd *abfd;
     asection *section;
     bfd_vma value;
{
  einfo ("%B: %s %s\n", abfd,
	 bfd_is_und_section (section) ? "reference to" : "definition of",
	 name);
  return true;
}