aboutsummaryrefslogtreecommitdiff
path: root/gold/plugin.cc
blob: 1c86c03b422415647dec82a80c0b781ae55e24ab (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
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
// plugin.cc -- plugin manager for gold      -*- C++ -*-

// Copyright 2008, 2009, 2010 Free Software Foundation, Inc.
// Written by Cary Coutant <ccoutant@google.com>.

// This file is part of gold.

// This program 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 3 of the License, or
// (at your option) any later version.

// This program 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 this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
// MA 02110-1301, USA.

#include "gold.h"

#include <cstdio>
#include <cstdarg>
#include <cstring>
#include <string>
#include <vector>

#ifdef ENABLE_PLUGINS
#include <dlfcn.h>
#endif

#include "parameters.h"
#include "errors.h"
#include "fileread.h"
#include "layout.h"
#include "options.h"
#include "plugin.h"
#include "target.h"
#include "readsyms.h"
#include "symtab.h"
#include "elfcpp.h"

namespace gold
{

#ifdef ENABLE_PLUGINS

// The linker's exported interfaces.

extern "C"
{

static enum ld_plugin_status
register_claim_file(ld_plugin_claim_file_handler handler);

static enum ld_plugin_status
register_all_symbols_read(ld_plugin_all_symbols_read_handler handler);

static enum ld_plugin_status
register_cleanup(ld_plugin_cleanup_handler handler);

static enum ld_plugin_status
add_symbols(void *handle, int nsyms, const struct ld_plugin_symbol *syms);

static enum ld_plugin_status
get_input_file(const void *handle, struct ld_plugin_input_file *file);

static enum ld_plugin_status
release_input_file(const void *handle);

static enum ld_plugin_status
get_symbols(const void *handle, int nsyms, struct ld_plugin_symbol *syms);

static enum ld_plugin_status
add_input_file(const char *pathname);

static enum ld_plugin_status
add_input_library(const char *pathname);

static enum ld_plugin_status
set_extra_library_path(const char *path);

static enum ld_plugin_status
message(int level, const char *format, ...);

};

#endif // ENABLE_PLUGINS

static Pluginobj* make_sized_plugin_object(Input_file* input_file,
                                           off_t offset, off_t filesize);

// Plugin methods.

// Load one plugin library.

void
Plugin::load()
{
#ifdef ENABLE_PLUGINS
  // Load the plugin library.
  // FIXME: Look for the library in standard locations.
  this->handle_ = dlopen(this->filename_.c_str(), RTLD_NOW);
  if (this->handle_ == NULL)
    {
      gold_error(_("%s: could not load plugin library: %s"),
                 this->filename_.c_str(), dlerror());
      return;
    }

  // Find the plugin's onload entry point.
  void* ptr = dlsym(this->handle_, "onload");
  if (ptr == NULL)
    {
      gold_error(_("%s: could not find onload entry point"),
                 this->filename_.c_str());
      return;
    }
  ld_plugin_onload onload;
  gold_assert(sizeof(onload) == sizeof(ptr));
  memcpy(&onload, &ptr, sizeof(ptr));

  // Get the linker's version number.
  const char* ver = get_version_string();
  int major = 0;
  int minor = 0;
  sscanf(ver, "%d.%d", &major, &minor);

  // Allocate and populate a transfer vector.
  const int tv_fixed_size = 16;
  int tv_size = this->args_.size() + tv_fixed_size;
  ld_plugin_tv *tv = new ld_plugin_tv[tv_size];

  // Put LDPT_MESSAGE at the front of the list so the plugin can use it
  // while processing subsequent entries.
  int i = 0;
  tv[i].tv_tag = LDPT_MESSAGE;
  tv[i].tv_u.tv_message = message;

  ++i;
  tv[i].tv_tag = LDPT_API_VERSION;
  tv[i].tv_u.tv_val = LD_PLUGIN_API_VERSION;

  ++i;
  tv[i].tv_tag = LDPT_GOLD_VERSION;
  tv[i].tv_u.tv_val = major * 100 + minor;

  ++i;
  tv[i].tv_tag = LDPT_LINKER_OUTPUT;
  if (parameters->options().relocatable())
    tv[i].tv_u.tv_val = LDPO_REL;
  else if (parameters->options().shared())
    tv[i].tv_u.tv_val = LDPO_DYN;
  else
    tv[i].tv_u.tv_val = LDPO_EXEC;

  ++i;
  tv[i].tv_tag = LDPT_OUTPUT_NAME;
  tv[i].tv_u.tv_string = parameters->options().output();

  for (unsigned int j = 0; j < this->args_.size(); ++j)
    {
      ++i;
      tv[i].tv_tag = LDPT_OPTION;
      tv[i].tv_u.tv_string = this->args_[j].c_str();
    }

  ++i;
  tv[i].tv_tag = LDPT_REGISTER_CLAIM_FILE_HOOK;
  tv[i].tv_u.tv_register_claim_file = register_claim_file;

  ++i;
  tv[i].tv_tag = LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK;
  tv[i].tv_u.tv_register_all_symbols_read = register_all_symbols_read;

  ++i;
  tv[i].tv_tag = LDPT_REGISTER_CLEANUP_HOOK;
  tv[i].tv_u.tv_register_cleanup = register_cleanup;

  ++i;
  tv[i].tv_tag = LDPT_ADD_SYMBOLS;
  tv[i].tv_u.tv_add_symbols = add_symbols;

  ++i;
  tv[i].tv_tag = LDPT_GET_INPUT_FILE;
  tv[i].tv_u.tv_get_input_file = get_input_file;

  ++i;
  tv[i].tv_tag = LDPT_RELEASE_INPUT_FILE;
  tv[i].tv_u.tv_release_input_file = release_input_file;

  ++i;
  tv[i].tv_tag = LDPT_GET_SYMBOLS;
  tv[i].tv_u.tv_get_symbols = get_symbols;

  ++i;
  tv[i].tv_tag = LDPT_ADD_INPUT_FILE;
  tv[i].tv_u.tv_add_input_file = add_input_file;

  ++i;
  tv[i].tv_tag = LDPT_ADD_INPUT_LIBRARY;
  tv[i].tv_u.tv_add_input_library = add_input_library;

  ++i;
  tv[i].tv_tag = LDPT_SET_EXTRA_LIBRARY_PATH;
  tv[i].tv_u.tv_set_extra_library_path = set_extra_library_path;

  ++i;
  tv[i].tv_tag = LDPT_NULL;
  tv[i].tv_u.tv_val = 0;

  gold_assert(i == tv_size - 1);

  // Call the onload entry point.
  (*onload)(tv);

  delete[] tv;
#endif // ENABLE_PLUGINS
}

// Call the plugin claim-file handler.

inline bool
Plugin::claim_file(struct ld_plugin_input_file *plugin_input_file)
{
  int claimed = 0;

  if (this->claim_file_handler_ != NULL)
    {
      (*this->claim_file_handler_)(plugin_input_file, &claimed);
      if (claimed)
        return true;
    }
  return false;
}

// Call the all-symbols-read handler.

inline void
Plugin::all_symbols_read()
{
  if (this->all_symbols_read_handler_ != NULL)
    (*this->all_symbols_read_handler_)();
}

// Call the cleanup handler.

inline void
Plugin::cleanup()
{
  if (this->cleanup_handler_ != NULL && !this->cleanup_done_)
    {
      // Set this flag before calling to prevent a recursive plunge
      // in the event that a plugin's cleanup handler issues a
      // fatal error.
      this->cleanup_done_ = true;
      (*this->cleanup_handler_)();
    }
}

// Plugin_manager methods.

Plugin_manager::~Plugin_manager()
{
  for (Plugin_list::iterator p = this->plugins_.begin();
       p != this->plugins_.end();
       ++p)
    delete *p;
  this->plugins_.clear();
  for (Object_list::iterator obj = this->objects_.begin();
       obj != this->objects_.end();
       ++obj)
    delete *obj;
  this->objects_.clear();
}

// Load all plugin libraries.

void
Plugin_manager::load_plugins()
{
  for (this->current_ = this->plugins_.begin();
       this->current_ != this->plugins_.end();
       ++this->current_)
    (*this->current_)->load();
}

// Call the plugin claim-file handlers in turn to see if any claim the file.

Pluginobj*
Plugin_manager::claim_file(Input_file* input_file, off_t offset,
                           off_t filesize)
{
  if (this->in_replacement_phase_)
    return NULL;

  unsigned int handle = this->objects_.size();
  this->input_file_ = input_file;
  this->plugin_input_file_.name = input_file->filename().c_str();
  this->plugin_input_file_.fd = input_file->file().descriptor();
  this->plugin_input_file_.offset = offset;
  this->plugin_input_file_.filesize = filesize;
  this->plugin_input_file_.handle = reinterpret_cast<void*>(handle);

  for (this->current_ = this->plugins_.begin();
       this->current_ != this->plugins_.end();
       ++this->current_)
    {
      if ((*this->current_)->claim_file(&this->plugin_input_file_))
        {
          if (this->objects_.size() > handle)
            return this->objects_[handle];

          // If the plugin claimed the file but did not call the
          // add_symbols callback, we need to create the Pluginobj now.
          Pluginobj* obj = this->make_plugin_object(handle);
          return obj;
        }
    }

  return NULL;
}

// Call the all-symbols-read handlers.

void
Plugin_manager::all_symbols_read(Workqueue* workqueue, Task* task,
                                 Input_objects* input_objects,
	                         Symbol_table* symtab, Layout* layout,
	                         Dirsearch* dirpath, Mapfile* mapfile,
	                         Task_token** last_blocker)
{
  this->in_replacement_phase_ = true;
  this->workqueue_ = workqueue;
  this->task_ = task;
  this->input_objects_ = input_objects;
  this->symtab_ = symtab;
  this->layout_ = layout;
  this->dirpath_ = dirpath;
  this->mapfile_ = mapfile;
  this->this_blocker_ = NULL;

  for (this->current_ = this->plugins_.begin();
       this->current_ != this->plugins_.end();
       ++this->current_)
    (*this->current_)->all_symbols_read();

  *last_blocker = this->this_blocker_;
}

// Layout deferred objects.

void
Plugin_manager::layout_deferred_objects()
{
  Deferred_layout_list::iterator obj;

  for (obj = this->deferred_layout_objects_.begin();
       obj != this->deferred_layout_objects_.end();
       ++obj)
    (*obj)->layout_deferred_sections(this->layout_);
}

// Call the cleanup handlers.

void
Plugin_manager::cleanup()
{
  for (this->current_ = this->plugins_.begin();
       this->current_ != this->plugins_.end();
       ++this->current_)
    (*this->current_)->cleanup();
}

// Make a new Pluginobj object.  This is called when the plugin calls
// the add_symbols API.

Pluginobj*
Plugin_manager::make_plugin_object(unsigned int handle)
{
  // Make sure we aren't asked to make an object for the same handle twice.
  if (this->objects_.size() != handle)
    return NULL;

  Pluginobj* obj = make_sized_plugin_object(this->input_file_,
                                            this->plugin_input_file_.offset,
                                            this->plugin_input_file_.filesize);
  this->objects_.push_back(obj);
  return obj;
}

// Get the input file information with an open (possibly re-opened)
// file descriptor.

ld_plugin_status
Plugin_manager::get_input_file(unsigned int handle,
                               struct ld_plugin_input_file *file)
{
  Pluginobj* obj = this->object(handle);
  if (obj == NULL)
    return LDPS_BAD_HANDLE;

  obj->lock(this->task_);
  file->name = obj->filename().c_str();
  file->fd = obj->descriptor();
  file->offset = obj->offset();
  file->filesize = obj->filesize();
  file->handle = reinterpret_cast<void*>(handle);
  return LDPS_OK;
}

// Release the input file.

ld_plugin_status
Plugin_manager::release_input_file(unsigned int handle)
{
  Pluginobj* obj = this->object(handle);
  if (obj == NULL)
    return LDPS_BAD_HANDLE;

  obj->unlock(this->task_);
  return LDPS_OK;
}

// Add a new library path.

ld_plugin_status
Plugin_manager::set_extra_library_path(const char *path)
{
  this->extra_search_path_ = std::string(path);
  return LDPS_OK;
}

// Add a new input file.

ld_plugin_status
Plugin_manager::add_input_file(const char *pathname, bool is_lib)
{
  Input_file_argument file(pathname,
                           (is_lib
                            ? Input_file_argument::INPUT_FILE_TYPE_LIBRARY
                            : Input_file_argument::INPUT_FILE_TYPE_FILE),
                           (is_lib
                            ? this->extra_search_path_.c_str()
                            : ""),
                           false,
                           this->options_);
  Input_argument* input_argument = new Input_argument(file);
  Task_token* next_blocker = new Task_token(true);
  next_blocker->add_blocker();
  if (this->layout_->incremental_inputs())
    gold_error(_("input files added by plug-ins in --incremental mode not "
		 "supported yet"));
  this->workqueue_->queue_soon(new Read_symbols(this->input_objects_,
                                                this->symtab_,
                                                this->layout_,
                                                this->dirpath_,
						0,
                                                this->mapfile_,
                                                input_argument,
                                                NULL,
                                                NULL,
                                                this->this_blocker_,
                                                next_blocker));
  this->this_blocker_ = next_blocker;
  return LDPS_OK;
}

// Class Pluginobj.

Pluginobj::Pluginobj(const std::string& name, Input_file* input_file,
                     off_t offset, off_t filesize)
  : Object(name, input_file, false, offset),
    nsyms_(0), syms_(NULL), symbols_(), filesize_(filesize), comdat_map_()
{
}

// Return TRUE if a defined symbol might be reachable from outside the
// universe of claimed objects.

static inline bool
is_visible_from_outside(Symbol* lsym)
{
  if (lsym->in_real_elf())
    return true;
  if (parameters->options().relocatable())
    return true;
  if (parameters->options().export_dynamic() || parameters->options().shared())
    return lsym->is_externally_visible();
  return false;
}

// Get symbol resolution info.

ld_plugin_status
Pluginobj::get_symbol_resolution_info(int nsyms, ld_plugin_symbol* syms) const
{
  if (nsyms > this->nsyms_)
    return LDPS_NO_SYMS;

  if (static_cast<size_t>(nsyms) > this->symbols_.size())
    {
      // We never decided to include this object. We mark all symbols as
      // preempted.
      gold_assert (this->symbols_.size() == 0);
      for (int i = 0; i < nsyms; i++)
        syms[i].resolution = LDPR_PREEMPTED_REG;
      return LDPS_OK;
    }

  for (int i = 0; i < nsyms; i++)
    {
      ld_plugin_symbol* isym = &syms[i];
      Symbol* lsym = this->symbols_[i];
      ld_plugin_symbol_resolution res = LDPR_UNKNOWN;

      if (lsym->is_undefined())
        // The symbol remains undefined.
        res = LDPR_UNDEF;
      else if (isym->def == LDPK_UNDEF
               || isym->def == LDPK_WEAKUNDEF
               || isym->def == LDPK_COMMON)
        {
          // The original symbol was undefined or common.
          if (lsym->source() != Symbol::FROM_OBJECT)
            res = LDPR_RESOLVED_EXEC;
          else if (lsym->object()->pluginobj() == this)
            res = (is_visible_from_outside(lsym)
                   ? LDPR_PREVAILING_DEF
                   : LDPR_PREVAILING_DEF_IRONLY);
          else if (lsym->object()->pluginobj() != NULL)
            res = LDPR_RESOLVED_IR;
          else if (lsym->object()->is_dynamic())
            res = LDPR_RESOLVED_DYN;
          else
            res = LDPR_RESOLVED_EXEC;
        }
      else
        {
          // The original symbol was a definition.
          if (lsym->source() != Symbol::FROM_OBJECT)
            res = LDPR_PREEMPTED_REG;
          else if (lsym->object() == static_cast<const Object*>(this))
            res = (is_visible_from_outside(lsym)
                   ? LDPR_PREVAILING_DEF
                   : LDPR_PREVAILING_DEF_IRONLY);
          else
            res = (lsym->object()->pluginobj() != NULL
                   ? LDPR_PREEMPTED_IR
                   : LDPR_PREEMPTED_REG);
        }
      isym->resolution = res;
    }
  return LDPS_OK;
}

// Return TRUE if the comdat group with key COMDAT_KEY from this object
// should be kept.

bool
Pluginobj::include_comdat_group(std::string comdat_key, Layout* layout)
{
  std::pair<Comdat_map::iterator, bool> ins =
    this->comdat_map_.insert(std::make_pair(comdat_key, false));

  // If this is the first time we've seen this comdat key, ask the
  // layout object whether it should be included.
  if (ins.second)
    ins.first->second = layout->find_or_add_kept_section(comdat_key,
							 NULL, 0, true,
							 true, NULL);

  return ins.first->second;
}

// Class Sized_pluginobj.

template<int size, bool big_endian>
Sized_pluginobj<size, big_endian>::Sized_pluginobj(
    const std::string& name,
    Input_file* input_file,
    off_t offset,
    off_t filesize)
  : Pluginobj(name, input_file, offset, filesize)
{
}

// Read the symbols.  Not used for plugin objects.

template<int size, bool big_endian>
void
Sized_pluginobj<size, big_endian>::do_read_symbols(Read_symbols_data*)
{
  gold_unreachable();
}

// Lay out the input sections.  Not used for plugin objects.

template<int size, bool big_endian>
void
Sized_pluginobj<size, big_endian>::do_layout(Symbol_table*, Layout*,
                                             Read_symbols_data*)
{
  gold_unreachable();
}

// Add the symbols to the symbol table.

template<int size, bool big_endian>
void
Sized_pluginobj<size, big_endian>::do_add_symbols(Symbol_table* symtab,
                                                  Read_symbols_data*,
                                                  Layout* layout)
{
  const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
  unsigned char symbuf[sym_size];
  elfcpp::Sym<size, big_endian> sym(symbuf);
  elfcpp::Sym_write<size, big_endian> osym(symbuf);

  typedef typename elfcpp::Elf_types<size>::Elf_WXword Elf_size_type;

  this->symbols_.resize(this->nsyms_);

  for (int i = 0; i < this->nsyms_; ++i)
    {
      const struct ld_plugin_symbol *isym = &this->syms_[i];
      const char* name = isym->name;
      const char* ver = isym->version;
      elfcpp::Elf_Half shndx;
      elfcpp::STB bind;
      elfcpp::STV vis;

      if (name != NULL && name[0] == '\0')
        name = NULL;
      if (ver != NULL && ver[0] == '\0')
        ver = NULL;

      switch (isym->def)
        {
        case LDPK_WEAKDEF:
        case LDPK_WEAKUNDEF:
          bind = elfcpp::STB_WEAK;
          break;
        case LDPK_DEF:
        case LDPK_UNDEF:
        case LDPK_COMMON:
        default:
          bind = elfcpp::STB_GLOBAL;
          break;
        }

      switch (isym->def)
        {
        case LDPK_DEF:
        case LDPK_WEAKDEF:
          shndx = elfcpp::SHN_ABS;
          break;
        case LDPK_COMMON:
          shndx = elfcpp::SHN_COMMON;
          break;
        case LDPK_UNDEF:
        case LDPK_WEAKUNDEF:
        default:
          shndx = elfcpp::SHN_UNDEF;
          break;
        }

      switch (isym->visibility)
        {
        case LDPV_PROTECTED:
          vis = elfcpp::STV_PROTECTED;
          break;
        case LDPV_INTERNAL:
          vis = elfcpp::STV_INTERNAL;
          break;
        case LDPV_HIDDEN:
          vis = elfcpp::STV_HIDDEN;
          break;
        case LDPV_DEFAULT:
        default:
          vis = elfcpp::STV_DEFAULT;
          break;
        }

      if (isym->comdat_key != NULL
          && isym->comdat_key[0] != '\0'
          && !this->include_comdat_group(isym->comdat_key, layout))
        shndx = elfcpp::SHN_UNDEF;

      osym.put_st_name(0);
      osym.put_st_value(0);
      osym.put_st_size(static_cast<Elf_size_type>(isym->size));
      osym.put_st_info(bind, elfcpp::STT_NOTYPE);
      osym.put_st_other(vis, 0);
      osym.put_st_shndx(shndx);

      this->symbols_[i] =
        symtab->add_from_pluginobj<size, big_endian>(this, name, ver, &sym);
    }
}

template<int size, bool big_endian>
Archive::Should_include
Sized_pluginobj<size, big_endian>::do_should_include_member(
    Symbol_table* symtab,
    Layout* layout,
    Read_symbols_data*,
    std::string* why)
{
  char* tmpbuf = NULL;
  size_t tmpbuflen = 0;

  for (int i = 0; i < this->nsyms_; ++i)
    {
      const struct ld_plugin_symbol& sym = this->syms_[i];
      const char* name = sym.name;
      Symbol* symbol;
      Archive::Should_include t = Archive::should_include_member(symtab,
								 layout,
								 name,
								 &symbol, why,
								 &tmpbuf,
								 &tmpbuflen);
      if (t == Archive::SHOULD_INCLUDE_YES)
	{
	  if (tmpbuf != NULL)
	    free(tmpbuf);
	  return t;
	}
    }
  if (tmpbuf != NULL)
    free(tmpbuf);
  return Archive::SHOULD_INCLUDE_UNKNOWN;
}

// Get the size of a section.  Not used for plugin objects.

template<int size, bool big_endian>
uint64_t
Sized_pluginobj<size, big_endian>::do_section_size(unsigned int)
{
  gold_unreachable();
  return 0;
}

// Get the name of a section.  Not used for plugin objects.

template<int size, bool big_endian>
std::string
Sized_pluginobj<size, big_endian>::do_section_name(unsigned int)
{
  gold_unreachable();
  return std::string();
}

// Return a view of the contents of a section.  Not used for plugin objects.

template<int size, bool big_endian>
Object::Location
Sized_pluginobj<size, big_endian>::do_section_contents(unsigned int)
{
  Location loc(0, 0);

  gold_unreachable();
  return loc;
}

// Return section flags.  Not used for plugin objects.

template<int size, bool big_endian>
uint64_t
Sized_pluginobj<size, big_endian>::do_section_flags(unsigned int)
{
  gold_unreachable();
  return 0;
}

// Return section entsize.  Not used for plugin objects.

template<int size, bool big_endian>
uint64_t
Sized_pluginobj<size, big_endian>::do_section_entsize(unsigned int)
{
  gold_unreachable();
  return 0;
}

// Return section address.  Not used for plugin objects.

template<int size, bool big_endian>
uint64_t
Sized_pluginobj<size, big_endian>::do_section_address(unsigned int)
{
  gold_unreachable();
  return 0;
}

// Return section type.  Not used for plugin objects.

template<int size, bool big_endian>
unsigned int
Sized_pluginobj<size, big_endian>::do_section_type(unsigned int)
{
  gold_unreachable();
  return 0;
}

// Return the section link field.  Not used for plugin objects.

template<int size, bool big_endian>
unsigned int
Sized_pluginobj<size, big_endian>::do_section_link(unsigned int)
{
  gold_unreachable();
  return 0;
}

// Return the section link field.  Not used for plugin objects.

template<int size, bool big_endian>
unsigned int
Sized_pluginobj<size, big_endian>::do_section_info(unsigned int)
{
  gold_unreachable();
  return 0;
}

// Return the section alignment.  Not used for plugin objects.

template<int size, bool big_endian>
uint64_t
Sized_pluginobj<size, big_endian>::do_section_addralign(unsigned int)
{
  gold_unreachable();
  return 0;
}

// Return the Xindex structure to use.  Not used for plugin objects.

template<int size, bool big_endian>
Xindex*
Sized_pluginobj<size, big_endian>::do_initialize_xindex()
{
  gold_unreachable();
  return NULL;
}

// Get symbol counts.  Not used for plugin objects.

template<int size, bool big_endian>
void
Sized_pluginobj<size, big_endian>::do_get_global_symbol_counts(const Symbol_table*,
                                                   size_t*, size_t*) const
{
  gold_unreachable();
}

// Get symbols.  Not used for plugin objects.

template<int size, bool big_endian>
const Object::Symbols*
Sized_pluginobj<size, big_endian>::do_get_global_symbols() const
{
  gold_unreachable();
}

// Class Plugin_finish.  This task runs after all replacement files have
// been added.  For now, it's a placeholder for a possible plugin API
// to allow the plugin to release most of its resources.  The cleanup
// handlers must be called later, because they can remove the temporary
// object files that are needed until the end of the link.

class Plugin_finish : public Task
{
 public:
  Plugin_finish(Task_token* this_blocker, Task_token* next_blocker)
    : this_blocker_(this_blocker), next_blocker_(next_blocker)
  { }

  ~Plugin_finish()
  {
    if (this->this_blocker_ != NULL)
      delete this->this_blocker_;
  }

  Task_token*
  is_runnable()
  {
    if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
      return this->this_blocker_;
    return NULL;
  }

  void
  locks(Task_locker* tl)
  { tl->add(this, this->next_blocker_); }

  void
  run(Workqueue*)
  {
    // We could call early cleanup handlers here.
  }

  std::string
  get_name() const
  { return "Plugin_finish"; }

 private:
  Task_token* this_blocker_;
  Task_token* next_blocker_;
};

// Class Plugin_hook.

Plugin_hook::~Plugin_hook()
{
}

// Return whether a Plugin_hook task is runnable.

Task_token*
Plugin_hook::is_runnable()
{
  if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
    return this->this_blocker_;
  return NULL;
}

// Return a Task_locker for a Plugin_hook task.  We don't need any
// locks here.

void
Plugin_hook::locks(Task_locker*)
{
}

// Run the "all symbols read" plugin hook.

void
Plugin_hook::run(Workqueue* workqueue)
{
  gold_assert(this->options_.has_plugins());
  Symbol* start_sym;
  if (parameters->options().entry())
    start_sym = this->symtab_->lookup(parameters->options().entry());
  else
    start_sym = this->symtab_->lookup("_start");
  if (start_sym != NULL)
    start_sym->set_in_real_elf();

  this->options_.plugins()->all_symbols_read(workqueue,
                                             this,
                                             this->input_objects_,
                                             this->symtab_,
                                             this->layout_,
                                             this->dirpath_,
                                             this->mapfile_,
                                             &this->this_blocker_);
  workqueue->queue_soon(new Plugin_finish(this->this_blocker_,
					  this->next_blocker_));
}

// The C interface routines called by the plugins.

#ifdef ENABLE_PLUGINS

// Register a claim-file handler.

static enum ld_plugin_status
register_claim_file(ld_plugin_claim_file_handler handler)
{
  gold_assert(parameters->options().has_plugins());
  parameters->options().plugins()->set_claim_file_handler(handler);
  return LDPS_OK;
}

// Register an all-symbols-read handler.

static enum ld_plugin_status
register_all_symbols_read(ld_plugin_all_symbols_read_handler handler)
{
  gold_assert(parameters->options().has_plugins());
  parameters->options().plugins()->set_all_symbols_read_handler(handler);
  return LDPS_OK;
}

// Register a cleanup handler.

static enum ld_plugin_status
register_cleanup(ld_plugin_cleanup_handler handler)
{
  gold_assert(parameters->options().has_plugins());
  parameters->options().plugins()->set_cleanup_handler(handler);
  return LDPS_OK;
}

// Add symbols from a plugin-claimed input file.

static enum ld_plugin_status
add_symbols(void* handle, int nsyms, const ld_plugin_symbol *syms)
{
  gold_assert(parameters->options().has_plugins());
  Pluginobj* obj = parameters->options().plugins()->make_plugin_object(
      static_cast<unsigned int>(reinterpret_cast<intptr_t>(handle)));
  if (obj == NULL)
    return LDPS_ERR;
  obj->store_incoming_symbols(nsyms, syms);
  return LDPS_OK;
}

// Get the input file information with an open (possibly re-opened)
// file descriptor.

static enum ld_plugin_status
get_input_file(const void *handle, struct ld_plugin_input_file *file)
{
  gold_assert(parameters->options().has_plugins());
  unsigned int obj_index =
      static_cast<unsigned int>(reinterpret_cast<intptr_t>(handle));
  return parameters->options().plugins()->get_input_file(obj_index, file);
}

// Release the input file.

static enum ld_plugin_status
release_input_file(const void *handle)
{
  gold_assert(parameters->options().has_plugins());
  unsigned int obj_index =
      static_cast<unsigned int>(reinterpret_cast<intptr_t>(handle));
  return parameters->options().plugins()->release_input_file(obj_index);
}

// Get the symbol resolution info for a plugin-claimed input file.

static enum ld_plugin_status
get_symbols(const void * handle, int nsyms, ld_plugin_symbol* syms)
{
  gold_assert(parameters->options().has_plugins());
  Pluginobj* obj = parameters->options().plugins()->object(
      static_cast<unsigned int>(reinterpret_cast<intptr_t>(handle)));
  if (obj == NULL)
    return LDPS_ERR;
  return obj->get_symbol_resolution_info(nsyms, syms);
}

// Add a new (real) input file generated by a plugin.

static enum ld_plugin_status
add_input_file(const char *pathname)
{
  gold_assert(parameters->options().has_plugins());
  return parameters->options().plugins()->add_input_file(pathname, false);
}

// Add a new (real) library required by a plugin.

static enum ld_plugin_status
add_input_library(const char *pathname)
{
  gold_assert(parameters->options().has_plugins());
  return parameters->options().plugins()->add_input_file(pathname, true);
}

// Set the extra library path to be used by libraries added via
// add_input_library

static enum ld_plugin_status
set_extra_library_path(const char *path)
{
  gold_assert(parameters->options().has_plugins());
  return parameters->options().plugins()->set_extra_library_path(path);
}

// Issue a diagnostic message from a plugin.

static enum ld_plugin_status
message(int level, const char * format, ...)
{
  va_list args;
  va_start(args, format);

  switch (level)
    {
    case LDPL_INFO:
      parameters->errors()->info(format, args);
      break;
    case LDPL_WARNING:
      parameters->errors()->warning(format, args);
      break;
    case LDPL_ERROR:
    default:
      parameters->errors()->error(format, args);
      break;
    case LDPL_FATAL:
      parameters->errors()->fatal(format, args);
      break;
    }

  va_end(args);
  return LDPS_OK;
}

#endif // ENABLE_PLUGINS

// Allocate a Pluginobj object of the appropriate size and endianness.

static Pluginobj*
make_sized_plugin_object(Input_file* input_file, off_t offset, off_t filesize)
{
  Pluginobj* obj = NULL;

  parameters_force_valid_target();
  const Target& target(parameters->target());

  if (target.get_size() == 32)
    {
      if (target.is_big_endian())
#ifdef HAVE_TARGET_32_BIG
        obj = new Sized_pluginobj<32, true>(input_file->filename(),
                                            input_file, offset, filesize);
#else
        gold_error(_("%s: not configured to support "
		     "32-bit big-endian object"),
		   input_file->filename().c_str());
#endif
      else
#ifdef HAVE_TARGET_32_LITTLE
        obj = new Sized_pluginobj<32, false>(input_file->filename(),
                                             input_file, offset, filesize);
#else
        gold_error(_("%s: not configured to support "
		     "32-bit little-endian object"),
		   input_file->filename().c_str());
#endif
    }
  else if (target.get_size() == 64)
    {
      if (target.is_big_endian())
#ifdef HAVE_TARGET_64_BIG
        obj = new Sized_pluginobj<64, true>(input_file->filename(),
                                            input_file, offset, filesize);
#else
        gold_error(_("%s: not configured to support "
		     "64-bit big-endian object"),
		   input_file->filename().c_str());
#endif
      else
#ifdef HAVE_TARGET_64_LITTLE
        obj = new Sized_pluginobj<64, false>(input_file->filename(),
                                             input_file, offset, filesize);
#else
        gold_error(_("%s: not configured to support "
		     "64-bit little-endian object"),
		   input_file->filename().c_str());
#endif
    }

  gold_assert(obj != NULL);
  return obj;
}

} // End namespace gold.