aboutsummaryrefslogtreecommitdiff
path: root/gold/reloc.h
blob: 0730a4570fc343a4d60dcf22aaa0b3e8b07dccc8 (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
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
// reloc.h -- relocate input files for gold   -*- C++ -*-

// Copyright (C) 2006-2016 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@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.

#ifndef GOLD_RELOC_H
#define GOLD_RELOC_H

#include <vector>
#ifdef HAVE_BYTESWAP_H
#include <byteswap.h>
#endif

#include "elfcpp.h"
#include "workqueue.h"

namespace gold
{

class General_options;
class Object;
class Relobj;
struct Read_relocs_data;
class Symbol;
class Layout;
class Output_data;
class Output_section;

template<int size>
class Sized_symbol;

template<int size, bool big_endian>
class Sized_relobj_file;

template<int size>
class Symbol_value;

template<int sh_type, bool dynamic, int size, bool big_endian>
class Output_data_reloc;

// A class to read the relocations for an object file, and then queue
// up a task to see if they require any GOT/PLT/COPY relocations in
// the symbol table.

class Read_relocs : public Task
{
 public:
  //   THIS_BLOCKER and NEXT_BLOCKER are passed along to a Scan_relocs
  // or Gc_process_relocs task, so that they run in a deterministic
  // order.
  Read_relocs(Symbol_table* symtab, Layout* layout, Relobj* object,
	      Task_token* this_blocker, Task_token* next_blocker)
    : symtab_(symtab), layout_(layout), object_(object),
      this_blocker_(this_blocker), next_blocker_(next_blocker)
  { }

  // The standard Task methods.

  Task_token*
  is_runnable();

  void
  locks(Task_locker*);

  void
  run(Workqueue*);

  std::string
  get_name() const;

 private:
  Symbol_table* symtab_;
  Layout* layout_;
  Relobj* object_;
  Task_token* this_blocker_;
  Task_token* next_blocker_;
};

// Process the relocs to figure out which sections are garbage.
// Very similar to scan relocs.

class Gc_process_relocs : public Task
{
 public:
  // THIS_BLOCKER prevents this task from running until the previous
  // one is finished.  NEXT_BLOCKER prevents the next task from
  // running.
  Gc_process_relocs(Symbol_table* symtab, Layout* layout, Relobj* object,
		    Read_relocs_data* rd, Task_token* this_blocker,
		    Task_token* next_blocker)
    : symtab_(symtab), layout_(layout), object_(object), rd_(rd),
      this_blocker_(this_blocker), next_blocker_(next_blocker)
  { }

  ~Gc_process_relocs();

  // The standard Task methods.

  Task_token*
  is_runnable();

  void
  locks(Task_locker*);

  void
  run(Workqueue*);

  std::string
  get_name() const;

 private:
  Symbol_table* symtab_;
  Layout* layout_;
  Relobj* object_;
  Read_relocs_data* rd_;
  Task_token* this_blocker_;
  Task_token* next_blocker_;
};

// Scan the relocations for an object to see if they require any
// GOT/PLT/COPY relocations.

class Scan_relocs : public Task
{
 public:
  // THIS_BLOCKER prevents this task from running until the previous
  // one is finished.  NEXT_BLOCKER prevents the next task from
  // running.
  Scan_relocs(Symbol_table* symtab, Layout* layout, Relobj* object,
	      Read_relocs_data* rd, Task_token* this_blocker,
	      Task_token* next_blocker)
    : symtab_(symtab), layout_(layout), object_(object), rd_(rd),
      this_blocker_(this_blocker), next_blocker_(next_blocker)
  { }

  ~Scan_relocs();

  // The standard Task methods.

  Task_token*
  is_runnable();

  void
  locks(Task_locker*);

  void
  run(Workqueue*);

  std::string
  get_name() const;

 private:
  Symbol_table* symtab_;
  Layout* layout_;
  Relobj* object_;
  Read_relocs_data* rd_;
  Task_token* this_blocker_;
  Task_token* next_blocker_;
};

// A class to perform all the relocations for an object file.

class Relocate_task : public Task
{
 public:
  Relocate_task(const Symbol_table* symtab, const Layout* layout,
		Relobj* object, Output_file* of,
		Task_token* input_sections_blocker,
		Task_token* output_sections_blocker, Task_token* final_blocker)
    : symtab_(symtab), layout_(layout), object_(object), of_(of),
      input_sections_blocker_(input_sections_blocker),
      output_sections_blocker_(output_sections_blocker),
      final_blocker_(final_blocker)
  { }

  // The standard Task methods.

  Task_token*
  is_runnable();

  void
  locks(Task_locker*);

  void
  run(Workqueue*);

  std::string
  get_name() const;

 private:
  const Symbol_table* symtab_;
  const Layout* layout_;
  Relobj* object_;
  Output_file* of_;
  Task_token* input_sections_blocker_;
  Task_token* output_sections_blocker_;
  Task_token* final_blocker_;
};

// During a relocatable link, this class records how relocations
// should be handled for a single input reloc section.  An instance of
// this class is created while scanning relocs, and it is used while
// processing relocs.

class Relocatable_relocs
{
 public:
  // We use a vector of unsigned char to indicate how the input relocs
  // should be handled.  Each element is one of the following values.
  // We create this vector when we initially scan the relocations.
  enum Reloc_strategy
  {
    // Copy the input reloc.  Don't modify it other than updating the
    // r_offset field and the r_sym part of the r_info field.
    RELOC_COPY,
    // Copy the input reloc which is against an STT_SECTION symbol.
    // Update the r_offset and r_sym part of the r_info field.  Adjust
    // the addend by subtracting the value of the old local symbol and
    // adding the value of the new local symbol.  The addend is in the
    // SHT_RELA reloc and the contents of the data section do not need
    // to be changed.
    RELOC_ADJUST_FOR_SECTION_RELA,
    // Like RELOC_ADJUST_FOR_SECTION_RELA but the addend should not be
    // adjusted.
    RELOC_ADJUST_FOR_SECTION_0,
    // Like RELOC_ADJUST_FOR_SECTION_RELA but the contents of the
    // section need to be changed.  The number indicates the number of
    // bytes in the addend in the section contents.
    RELOC_ADJUST_FOR_SECTION_1,
    RELOC_ADJUST_FOR_SECTION_2,
    RELOC_ADJUST_FOR_SECTION_4,
    RELOC_ADJUST_FOR_SECTION_8,
    // Like RELOC_ADJUST_FOR_SECTION_4 but for unaligned relocs.
    RELOC_ADJUST_FOR_SECTION_4_UNALIGNED,
    // Discard the input reloc--process it completely when relocating
    // the data section contents.
    RELOC_DISCARD,
    // An input reloc which is not discarded, but which requires
    // target specific processing in order to update it.
    RELOC_SPECIAL
  };

  Relocatable_relocs()
    : reloc_strategies_(), output_reloc_count_(0), posd_(NULL)
  { }

  // Record the number of relocs.
  void
  set_reloc_count(size_t reloc_count)
  { this->reloc_strategies_.reserve(reloc_count); }

  // Record what to do for the next reloc.
  void
  set_next_reloc_strategy(Reloc_strategy strategy)
  {
    this->reloc_strategies_.push_back(static_cast<unsigned char>(strategy));
    if (strategy != RELOC_DISCARD)
      ++this->output_reloc_count_;
  }

  // Record the Output_data associated with this reloc section.
  void
  set_output_data(Output_data* posd)
  {
    gold_assert(this->posd_ == NULL);
    this->posd_ = posd;
  }

  // Return the Output_data associated with this reloc section.
  Output_data*
  output_data() const
  { return this->posd_; }

  // Return what to do for reloc I.
  Reloc_strategy
  strategy(unsigned int i) const
  {
    gold_assert(i < this->reloc_strategies_.size());
    return static_cast<Reloc_strategy>(this->reloc_strategies_[i]);
  }

  // Set the strategy for reloc I.
  void
  set_strategy(unsigned int i, Reloc_strategy strategy)
  {
    gold_assert(i < this->reloc_strategies_.size());
    this->reloc_strategies_[i] = strategy;
  }

  // Return the number of relocations to create in the output file.
  size_t
  output_reloc_count() const
  { return this->output_reloc_count_; }

 private:
  typedef std::vector<unsigned char> Reloc_strategies;

  // The strategies for the input reloc.  There is one entry in this
  // vector for each relocation in the input section.
  Reloc_strategies reloc_strategies_;
  // The number of relocations to be created in the output file.
  size_t output_reloc_count_;
  // The output data structure associated with this relocation.
  Output_data* posd_;
};

template<int valsize>
class Bits;

// Standard relocation routines which are used on many targets.  Here
// SIZE and BIG_ENDIAN refer to the target, not the relocation type.

template<int size, bool big_endian>
class Relocate_functions
{
 public:
  typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
  typedef typename elfcpp::Elf_types<size>::Elf_Swxword Addendtype;

  enum Overflow_check
  {
    // No overflow checking.
    CHECK_NONE,
    // Check for overflow of a signed value.
    CHECK_SIGNED,
    // Check for overflow of an unsigned value.
    CHECK_UNSIGNED,
    // Check for overflow of a signed or unsigned value.
    // (i.e., no error if either signed or unsigned fits.)
    CHECK_SIGNED_OR_UNSIGNED
  };

  enum Reloc_status
  {
    RELOC_OK,
    RELOC_OVERFLOW
  };

 private:
  // Check for overflow.
  template<int valsize>
  static inline Reloc_status
  check_overflow(Address value, Overflow_check check)
  {
    switch (check)
      {
      case CHECK_SIGNED:
        if (size == 32)
	  return (Bits<valsize>::has_overflow32(value)
		  ? RELOC_OVERFLOW
		  : RELOC_OK);
	else
	  return (Bits<valsize>::has_overflow(value)
		  ? RELOC_OVERFLOW
		  : RELOC_OK);
      case CHECK_UNSIGNED:
        if (size == 32)
	  return (Bits<valsize>::has_unsigned_overflow32(value)
		  ? RELOC_OVERFLOW
		  : RELOC_OK);
	else
	  return (Bits<valsize>::has_unsigned_overflow(value)
		  ? RELOC_OVERFLOW
		  : RELOC_OK);
      case CHECK_SIGNED_OR_UNSIGNED:
        if (size == 32)
	  return (Bits<valsize>::has_signed_unsigned_overflow32(value)
		  ? RELOC_OVERFLOW
		  : RELOC_OK);
	else
	  return (Bits<valsize>::has_signed_unsigned_overflow64(value)
		  ? RELOC_OVERFLOW
		  : RELOC_OK);
      case CHECK_NONE:
      default:
        return RELOC_OK;
      }
  }

  // Do a simple relocation with the addend in the section contents.
  // VALSIZE is the size of the value.
  template<int valsize>
  static inline Reloc_status
  rel(unsigned char* view, Address value, Overflow_check check)
  {
    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
    Valtype* wv = reinterpret_cast<Valtype*>(view);
    Valtype addend = elfcpp::Swap<valsize, big_endian>::readval(wv);
    value += addend;
    elfcpp::Swap<valsize, big_endian>::
	writeval(wv, static_cast<Valtype>(value));
    return check_overflow<valsize>(value, check);
  }

  // Like the above but for relocs at unaligned addresses.
  template<int valsize>
  static inline Reloc_status
  rel_unaligned(unsigned char* view, Address value, Overflow_check check)
  {
    typedef typename elfcpp::Swap_unaligned<valsize, big_endian>::Valtype
	Valtype;
    Valtype addend = elfcpp::Swap_unaligned<valsize, big_endian>::readval(view);
    value += addend;
    elfcpp::Swap_unaligned<valsize, big_endian>::
	writeval(view, static_cast<Valtype>(value));
    return check_overflow<valsize>(value, check);
  }

  // Do a simple relocation using a Symbol_value with the addend in
  // the section contents.  VALSIZE is the size of the value to
  // relocate.
  template<int valsize>
  static inline Reloc_status
  rel(unsigned char* view,
      const Sized_relobj_file<size, big_endian>* object,
      const Symbol_value<size>* psymval,
      Overflow_check check)
  {
    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
    Valtype* wv = reinterpret_cast<Valtype*>(view);
    Valtype addend = elfcpp::Swap<valsize, big_endian>::readval(wv);
    Address value = psymval->value(object, addend);
    elfcpp::Swap<valsize, big_endian>::
	writeval(wv, static_cast<Valtype>(value));
    return check_overflow<valsize>(value, check);
  }

  // Like the above but for relocs at unaligned addresses.
  template<int valsize>
  static inline Reloc_status
  rel_unaligned(unsigned char* view,
                const Sized_relobj_file<size, big_endian>* object,
                const Symbol_value<size>* psymval,
                Overflow_check check)
  {
    typedef typename elfcpp::Swap_unaligned<valsize, big_endian>::Valtype
        Valtype;
    Valtype addend = elfcpp::Swap_unaligned<valsize, big_endian>::readval(view);
    Address value = psymval->value(object, addend);
    elfcpp::Swap_unaligned<valsize, big_endian>::writeval(view, value);
    return check_overflow<valsize>(value, check);
  }

  // Do a simple relocation with the addend in the relocation.
  // VALSIZE is the size of the value.
  template<int valsize>
  static inline Reloc_status
  rela(unsigned char* view, Address value, Addendtype addend,
       Overflow_check check)
  {
    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
    Valtype* wv = reinterpret_cast<Valtype*>(view);
    value += addend;
    elfcpp::Swap<valsize, big_endian>::writeval(wv, value);
    return check_overflow<valsize>(value, check);
  }

  // Do a simple relocation using a symbol value with the addend in
  // the relocation.  VALSIZE is the size of the value.
  template<int valsize>
  static inline Reloc_status
  rela(unsigned char* view,
       const Sized_relobj_file<size, big_endian>* object,
       const Symbol_value<size>* psymval,
       Addendtype addend,
       Overflow_check check)
  {
    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
    Valtype* wv = reinterpret_cast<Valtype*>(view);
    Address value = psymval->value(object, addend);
    elfcpp::Swap<valsize, big_endian>::writeval(wv, value);
    return check_overflow<valsize>(value, check);
  }

  // Do a simple PC relative relocation with the addend in the section
  // contents.  VALSIZE is the size of the value.
  template<int valsize>
  static inline Reloc_status
  pcrel(unsigned char* view, Address value, Address address,
	Overflow_check check)
  {
    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
    Valtype* wv = reinterpret_cast<Valtype*>(view);
    Valtype addend = elfcpp::Swap<valsize, big_endian>::readval(wv);
    value = value + addend - address;
    elfcpp::Swap<valsize, big_endian>::writeval(wv, value);
    return check_overflow<valsize>(value, check);
  }

  // Like the above but for relocs at unaligned addresses.
  template<int valsize>
  static inline Reloc_status
  pcrel_unaligned(unsigned char* view, Address value, Address address,
		  Overflow_check check)
  {
    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
    Valtype addend = elfcpp::Swap_unaligned<valsize, big_endian>::readval(view);
    value = value + addend - address;
    elfcpp::Swap_unaligned<valsize, big_endian>::writeval(view, value);
    return check_overflow<valsize>(value, check);
  }

  // Do a simple PC relative relocation with a Symbol_value with the
  // addend in the section contents.  VALSIZE is the size of the
  // value.
  template<int valsize>
  static inline Reloc_status
  pcrel(unsigned char* view,
	const Sized_relobj_file<size, big_endian>* object,
	const Symbol_value<size>* psymval,
	Address address,
	Overflow_check check)
  {
    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
    Valtype* wv = reinterpret_cast<Valtype*>(view);
    Valtype addend = elfcpp::Swap<valsize, big_endian>::readval(wv);
    Address value = psymval->value(object, addend) - address;
    elfcpp::Swap<valsize, big_endian>::writeval(wv, value);
    return check_overflow<valsize>(value, check);
  }

  // Do a simple PC relative relocation with the addend in the
  // relocation.  VALSIZE is the size of the value.
  template<int valsize>
  static inline Reloc_status
  pcrela(unsigned char* view, Address value, Addendtype addend, Address address,
	 Overflow_check check)
  {
    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
    Valtype* wv = reinterpret_cast<Valtype*>(view);
    value = value + addend - address;
    elfcpp::Swap<valsize, big_endian>::writeval(wv, value);
    return check_overflow<valsize>(value, check);
  }

  // Do a simple PC relative relocation with a Symbol_value with the
  // addend in the relocation.  VALSIZE is the size of the value.
  template<int valsize>
  static inline Reloc_status
  pcrela(unsigned char* view,
	 const Sized_relobj_file<size, big_endian>* object,
	 const Symbol_value<size>* psymval,
	 Addendtype addend,
	 Address address,
	 Overflow_check check)
  {
    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
    Valtype* wv = reinterpret_cast<Valtype*>(view);
    Address value = psymval->value(object, addend) - address;
    elfcpp::Swap<valsize, big_endian>::writeval(wv, value);
    return check_overflow<valsize>(value, check);
  }

  typedef Relocate_functions<size, big_endian> This;

 public:
  // Do a simple 8-bit REL relocation with the addend in the section
  // contents.
  static inline void
  rel8(unsigned char* view, Address value)
  { This::template rel<8>(view, value, CHECK_NONE); }

  static inline Reloc_status
  rel8_check(unsigned char* view, Address value, Overflow_check check)
  { return This::template rel<8>(view, value, check); }

  static inline void
  rel8(unsigned char* view,
       const Sized_relobj_file<size, big_endian>* object,
       const Symbol_value<size>* psymval)
  { This::template rel<8>(view, object, psymval, CHECK_NONE); }

  static inline Reloc_status
  rel8_check(unsigned char* view,
	     const Sized_relobj_file<size, big_endian>* object,
	     const Symbol_value<size>* psymval,
	     Overflow_check check)
  { return This::template rel<8>(view, object, psymval, check); }

  // Do an 8-bit RELA relocation with the addend in the relocation.
  static inline void
  rela8(unsigned char* view, Address value, Addendtype addend)
  { This::template rela<8>(view, value, addend, CHECK_NONE); }

  static inline Reloc_status
  rela8_check(unsigned char* view, Address value, Addendtype addend,
	      Overflow_check check)
  { return This::template rela<8>(view, value, addend, check); }

  static inline void
  rela8(unsigned char* view,
	const Sized_relobj_file<size, big_endian>* object,
	const Symbol_value<size>* psymval,
	Addendtype addend)
  { This::template rela<8>(view, object, psymval, addend, CHECK_NONE); }

  static inline Reloc_status
  rela8_check(unsigned char* view,
	      const Sized_relobj_file<size, big_endian>* object,
	      const Symbol_value<size>* psymval,
	      Addendtype addend,
	      Overflow_check check)
  { return This::template rela<8>(view, object, psymval, addend, check); }

  // Do a simple 8-bit PC relative relocation with the addend in the
  // section contents.
  static inline void
  pcrel8(unsigned char* view, unsigned char value, Address address)
  { This::template pcrel<8>(view, value, address, CHECK_NONE); }

  static inline Reloc_status
  pcrel8_check(unsigned char* view, unsigned char value, Address address,
	       Overflow_check check)
  { return This::template pcrel<8>(view, value, address, check); }

  static inline void
  pcrel8(unsigned char* view,
	 const Sized_relobj_file<size, big_endian>* object,
	 const Symbol_value<size>* psymval,
	 Address address)
  { This::template pcrel<8>(view, object, psymval, address, CHECK_NONE); }

  static inline Reloc_status
  pcrel8_check(unsigned char* view,
	       const Sized_relobj_file<size, big_endian>* object,
	       const Symbol_value<size>* psymval,
	       Address address,
	       Overflow_check check)
  { return This::template pcrel<8>(view, object, psymval, address, check); }

  // Do a simple 8-bit PC relative RELA relocation with the addend in
  // the reloc.
  static inline void
  pcrela8(unsigned char* view, Address value, Addendtype addend,
	  Address address)
  { This::template pcrela<8>(view, value, addend, address, CHECK_NONE); }

  static inline Reloc_status
  pcrela8_check(unsigned char* view, Address value, Addendtype addend,
		Address address, Overflow_check check)
  { return This::template pcrela<8>(view, value, addend, address, check); }

  static inline void
  pcrela8(unsigned char* view,
	  const Sized_relobj_file<size, big_endian>* object,
	  const Symbol_value<size>* psymval,
	  Addendtype addend,
	  Address address)
  { This::template pcrela<8>(view, object, psymval, addend, address,
			     CHECK_NONE); }

  static inline Reloc_status
  pcrela8_check(unsigned char* view,
		const Sized_relobj_file<size, big_endian>* object,
		const Symbol_value<size>* psymval,
		Addendtype addend,
		Address address,
		Overflow_check check)
  { return This::template pcrela<8>(view, object, psymval, addend, address,
				    check); }

  // Do a simple 16-bit REL relocation with the addend in the section
  // contents.
  static inline void
  rel16(unsigned char* view, Address value)
  { This::template rel<16>(view, value, CHECK_NONE); }

  static inline Reloc_status
  rel16_check(unsigned char* view, Address value, Overflow_check check)
  { return This::template rel<16>(view, value, check); }

  static inline void
  rel16(unsigned char* view,
	const Sized_relobj_file<size, big_endian>* object,
	const Symbol_value<size>* psymval)
  { This::template rel<16>(view, object, psymval, CHECK_NONE); }

  static inline Reloc_status
  rel16_check(unsigned char* view,
	      const Sized_relobj_file<size, big_endian>* object,
	      const Symbol_value<size>* psymval,
	      Overflow_check check)
  { return This::template rel<16>(view, object, psymval, check); }

  // Do an 16-bit RELA relocation with the addend in the relocation.
  static inline void
  rela16(unsigned char* view, Address value, Addendtype addend)
  { This::template rela<16>(view, value, addend, CHECK_NONE); }

  static inline Reloc_status
  rela16_check(unsigned char* view, Address value, Addendtype addend,
	       Overflow_check check)
  { return This::template rela<16>(view, value, addend, check); }

  static inline void
  rela16(unsigned char* view,
	 const Sized_relobj_file<size, big_endian>* object,
	 const Symbol_value<size>* psymval,
	 Addendtype addend)
  { This::template rela<16>(view, object, psymval, addend, CHECK_NONE); }

  static inline Reloc_status
  rela16_check(unsigned char* view,
	       const Sized_relobj_file<size, big_endian>* object,
	       const Symbol_value<size>* psymval,
	       Addendtype addend,
	       Overflow_check check)
  { return This::template rela<16>(view, object, psymval, addend, check); }

  // Do a simple 16-bit PC relative REL relocation with the addend in
  // the section contents.
  static inline void
  pcrel16(unsigned char* view, Address value, Address address)
  { This::template pcrel<16>(view, value, address, CHECK_NONE); }

  static inline Reloc_status
  pcrel16_check(unsigned char* view, Address value, Address address,
		Overflow_check check)
  { return This::template pcrel<16>(view, value, address, check); }

  static inline void
  pcrel16(unsigned char* view,
	  const Sized_relobj_file<size, big_endian>* object,
	  const Symbol_value<size>* psymval,
	  Address address)
  { This::template pcrel<16>(view, object, psymval, address, CHECK_NONE); }

  static inline Reloc_status
  pcrel16_check(unsigned char* view,
		const Sized_relobj_file<size, big_endian>* object,
		const Symbol_value<size>* psymval,
		Address address,
		Overflow_check check)
  { return This::template pcrel<16>(view, object, psymval, address, check); }

  // Do a simple 16-bit PC relative RELA relocation with the addend in
  // the reloc.
  static inline void
  pcrela16(unsigned char* view, Address value, Addendtype addend,
	   Address address)
  { This::template pcrela<16>(view, value, addend, address, CHECK_NONE); }

  static inline Reloc_status
  pcrela16_check(unsigned char* view, Address value, Addendtype addend,
		 Address address, Overflow_check check)
  { return This::template pcrela<16>(view, value, addend, address, check); }

  static inline void
  pcrela16(unsigned char* view,
	   const Sized_relobj_file<size, big_endian>* object,
	   const Symbol_value<size>* psymval,
	   Addendtype addend,
	   Address address)
  { This::template pcrela<16>(view, object, psymval, addend, address,
			      CHECK_NONE); }

  static inline Reloc_status
  pcrela16_check(unsigned char* view,
		 const Sized_relobj_file<size, big_endian>* object,
		 const Symbol_value<size>* psymval,
		 Addendtype addend,
		 Address address,
		 Overflow_check check)
  { return This::template pcrela<16>(view, object, psymval, addend, address,
				     check); }

  // Do a simple 32-bit REL relocation with the addend in the section
  // contents.
  static inline void
  rel32(unsigned char* view, Address value)
  { This::template rel<32>(view, value, CHECK_NONE); }

  static inline Reloc_status
  rel32_check(unsigned char* view, Address value, Overflow_check check)
  { return This::template rel<32>(view, value, check); }

  // Like above but for relocs at unaligned addresses.
  static inline void
  rel32_unaligned(unsigned char* view, Address value)
  { This::template rel_unaligned<32>(view, value, CHECK_NONE); }

  static inline Reloc_status
  rel32_unaligned_check(unsigned char* view, Address value,
			Overflow_check check)
  { return This::template rel_unaligned<32>(view, value, check); }

  static inline void
  rel32(unsigned char* view,
	const Sized_relobj_file<size, big_endian>* object,
	const Symbol_value<size>* psymval)
  { This::template rel<32>(view, object, psymval, CHECK_NONE); }

  static inline Reloc_status
  rel32_check(unsigned char* view,
	      const Sized_relobj_file<size, big_endian>* object,
	      const Symbol_value<size>* psymval,
	      Overflow_check check)
  { return This::template rel<32>(view, object, psymval, check); }

  // Like above but for relocs at unaligned addresses.
  static inline void
  rel32_unaligned(unsigned char* view,
	          const Sized_relobj_file<size, big_endian>* object,
	          const Symbol_value<size>* psymval)
  { This::template rel_unaligned<32>(view, object, psymval, CHECK_NONE); }

  static inline Reloc_status
  rel32_unaligned_check(unsigned char* view,
			const Sized_relobj_file<size, big_endian>* object,
			const Symbol_value<size>* psymval,
			Overflow_check check)
  { return This::template rel_unaligned<32>(view, object, psymval, check); }

  // Do a 32-bit RELA relocation with the addend in the relocation.
  static inline void
  rela32(unsigned char* view, Address value, Addendtype addend)
  { This::template rela<32>(view, value, addend, CHECK_NONE); }

  static inline Reloc_status
  rela32(unsigned char* view, Address value, Addendtype addend,
	 Overflow_check check)
  { return This::template rela<32>(view, value, addend, check); }

  static inline void
  rela32(unsigned char* view,
	 const Sized_relobj_file<size, big_endian>* object,
	 const Symbol_value<size>* psymval,
	 Addendtype addend)
  { This::template rela<32>(view, object, psymval, addend, CHECK_NONE); }

  static inline Reloc_status
  rela32_check(unsigned char* view,
	       const Sized_relobj_file<size, big_endian>* object,
	       const Symbol_value<size>* psymval,
	       Addendtype addend,
	       Overflow_check check)
  { return This::template rela<32>(view, object, psymval, addend, check); }

  // Do a simple 32-bit PC relative REL relocation with the addend in
  // the section contents.
  static inline void
  pcrel32(unsigned char* view, Address value, Address address)
  { This::template pcrel<32>(view, value, address, CHECK_NONE); }

  static inline Reloc_status
  pcrel32_check(unsigned char* view, Address value, Address address,
		Overflow_check check)
  { return This::template pcrel<32>(view, value, address, check); }

  // Unaligned version of the above.
  static inline void
  pcrel32_unaligned(unsigned char* view, Address value, Address address)
  { This::template pcrel_unaligned<32>(view, value, address, CHECK_NONE); }

  static inline Reloc_status
  pcrel32_unaligned_check(unsigned char* view, Address value, Address address,
			  Overflow_check check)
  { return This::template pcrel_unaligned<32>(view, value, address, check); }

  static inline void
  pcrel32(unsigned char* view,
	  const Sized_relobj_file<size, big_endian>* object,
	  const Symbol_value<size>* psymval,
	  Address address)
  { This::template pcrel<32>(view, object, psymval, address, CHECK_NONE); }

  static inline Reloc_status
  pcrel32_check(unsigned char* view,
		const Sized_relobj_file<size, big_endian>* object,
		const Symbol_value<size>* psymval,
		Address address,
		Overflow_check check)
  { return This::template pcrel<32>(view, object, psymval, address, check); }

  // Do a simple 32-bit PC relative RELA relocation with the addend in
  // the relocation.
  static inline void
  pcrela32(unsigned char* view, Address value, Addendtype addend,
           Address address)
  { This::template pcrela<32>(view, value, addend, address, CHECK_NONE); }

  static inline Reloc_status
  pcrela32_check(unsigned char* view, Address value, Addendtype addend,
           Address address, Overflow_check check)
  { return This::template pcrela<32>(view, value, addend, address, check); }

  static inline void
  pcrela32(unsigned char* view,
	   const Sized_relobj_file<size, big_endian>* object,
	   const Symbol_value<size>* psymval,
	   Addendtype addend,
	   Address address)
  { This::template pcrela<32>(view, object, psymval, addend, address,
			      CHECK_NONE); }

  static inline Reloc_status
  pcrela32_check(unsigned char* view,
	   const Sized_relobj_file<size, big_endian>* object,
	   const Symbol_value<size>* psymval,
	   Addendtype addend,
	   Address address,
	   Overflow_check check)
  { return This::template pcrela<32>(view, object, psymval, addend, address,
				     check); }

  // Do a simple 64-bit REL relocation with the addend in the section
  // contents.
  static inline void
  rel64(unsigned char* view, Address value)
  { This::template rel<64>(view, value, CHECK_NONE); }

  static inline void
  rel64(unsigned char* view,
	const Sized_relobj_file<size, big_endian>* object,
	const Symbol_value<size>* psymval)
  { This::template rel<64>(view, object, psymval, CHECK_NONE); }

  // Do a 64-bit RELA relocation with the addend in the relocation.
  static inline void
  rela64(unsigned char* view, Address value, Addendtype addend)
  { This::template rela<64>(view, value, addend, CHECK_NONE); }

  static inline void
  rela64(unsigned char* view,
	 const Sized_relobj_file<size, big_endian>* object,
	 const Symbol_value<size>* psymval,
	 Addendtype addend)
  { This::template rela<64>(view, object, psymval, addend, CHECK_NONE); }

  // Do a simple 64-bit PC relative REL relocation with the addend in
  // the section contents.
  static inline void
  pcrel64(unsigned char* view, Address value, Address address)
  { This::template pcrel<64>(view, value, address, CHECK_NONE); }

  static inline void
  pcrel64(unsigned char* view,
	  const Sized_relobj_file<size, big_endian>* object,
	  const Symbol_value<size>* psymval,
	  Address address)
  { This::template pcrel<64>(view, object, psymval, address, CHECK_NONE); }

  // Do a simple 64-bit PC relative RELA relocation with the addend in
  // the relocation.
  static inline void
  pcrela64(unsigned char* view, Address value, Addendtype addend,
	   Address address)
  { This::template pcrela<64>(view, value, addend, address, CHECK_NONE); }

  static inline void
  pcrela64(unsigned char* view,
	   const Sized_relobj_file<size, big_endian>* object,
	   const Symbol_value<size>* psymval,
	   Addendtype addend,
	   Address address)
  { This::template pcrela<64>(view, object, psymval, addend, address,
			      CHECK_NONE); }
};

// Convenience class for min and max values of a given BITS length.

template<int bits>
class Limits
{
 public:
  static const uint64_t MAX_UNSIGNED = (1ULL << bits) - 1;
  static const int64_t MAX_SIGNED = MAX_UNSIGNED >> 1;
  static const int64_t MIN_SIGNED = -MAX_SIGNED - 1;
};

template<>
class Limits<64>
{
 public:
  static const uint64_t MAX_UNSIGNED = ~0ULL;
  static const int64_t MAX_SIGNED = MAX_UNSIGNED >> 1;
  static const int64_t MIN_SIGNED = -MAX_SIGNED - 1;
};

// Integer manipulation functions used by various targets when
// performing relocations.

template<int bits>
class Bits
{
 public:
  // Sign extend an n-bit unsigned integer stored in a uint32_t into
  // an int32_t.  BITS must be between 1 and 32.
  static inline int32_t
  sign_extend32(uint32_t val)
  {
    gold_assert(bits > 0 && bits <= 32);
    if (bits == 32)
      return static_cast<int32_t>(val);
    uint32_t mask = (~static_cast<uint32_t>(0)) >> (32 - bits);
    val &= mask;
    uint32_t top_bit = 1U << (bits - 1);
    int32_t as_signed = static_cast<int32_t>(val);
    if ((val & top_bit) != 0)
      as_signed -= static_cast<int32_t>(top_bit * 2);
    return as_signed;    
  }

  // Return true if VAL (stored in a uint32_t) has overflowed a signed
  // value with BITS bits.
  static inline bool
  has_overflow32(uint32_t val)
  {
    gold_assert(bits > 0 && bits <= 32);
    if (bits == 32)
      return false;
    const int32_t max = static_cast<int32_t>(Limits<bits>::MAX_SIGNED);
    const int32_t min = static_cast<int32_t>(Limits<bits>::MIN_SIGNED);
    int32_t as_signed = static_cast<int32_t>(val);
    return as_signed > max || as_signed < min;
  }

  // Return true if VAL (stored in a uint32_t) has overflowed an unsigned
  // value with BITS bits.
  static inline bool
  has_unsigned_overflow32(uint32_t val)
  {
    gold_assert(bits > 0 && bits <= 32);
    if (bits == 32)
      return false;
    const uint32_t max = static_cast<uint32_t>(Limits<bits>::MAX_UNSIGNED);
    return val > max;
  }

  // Return true if VAL (stored in a uint32_t) has overflowed both a
  // signed and an unsigned value.  E.g.,
  // Bits<8>::has_signed_unsigned_overflow32 would check -128 <= VAL <
  // 255.
  static inline bool
  has_signed_unsigned_overflow32(uint32_t val)
  {
    gold_assert(bits > 0 && bits <= 32);
    if (bits == 32)
      return false;
    const int32_t max = static_cast<int32_t>(Limits<bits>::MAX_UNSIGNED);
    const int32_t min = static_cast<int32_t>(Limits<bits>::MIN_SIGNED);
    int32_t as_signed = static_cast<int32_t>(val);
    return as_signed > max || as_signed < min;
  }

  // Select bits from A and B using bits in MASK.  For each n in
  // [0..31], the n-th bit in the result is chosen from the n-th bits
  // of A and B.  A zero selects A and a one selects B.
  static inline uint32_t
  bit_select32(uint32_t a, uint32_t b, uint32_t mask)
  { return (a & ~mask) | (b & mask); }

  // Sign extend an n-bit unsigned integer stored in a uint64_t into
  // an int64_t.  BITS must be between 1 and 64.
  static inline int64_t
  sign_extend(uint64_t val)
  {
    gold_assert(bits > 0 && bits <= 64);
    if (bits == 64)
      return static_cast<int64_t>(val);
    uint64_t mask = (~static_cast<uint64_t>(0)) >> (64 - bits);
    val &= mask;
    uint64_t top_bit = static_cast<uint64_t>(1) << (bits - 1);
    int64_t as_signed = static_cast<int64_t>(val);
    if ((val & top_bit) != 0)
      as_signed -= static_cast<int64_t>(top_bit * 2);
    return as_signed;    
  }

  // Return true if VAL (stored in a uint64_t) has overflowed a signed
  // value with BITS bits.
  static inline bool
  has_overflow(uint64_t val)
  {
    gold_assert(bits > 0 && bits <= 64);
    if (bits == 64)
      return false;
    const int64_t max = Limits<bits>::MAX_SIGNED;
    const int64_t min = Limits<bits>::MIN_SIGNED;
    int64_t as_signed = static_cast<int64_t>(val);
    return as_signed > max || as_signed < min;
  }

  // Return true if VAL (stored in a uint64_t) has overflowed an unsigned
  // value with BITS bits.
  static inline bool
  has_unsigned_overflow(uint64_t val)
  {
    gold_assert(bits > 0 && bits <= 64);
    if (bits == 64)
      return false;
    const uint64_t max = Limits<bits>::MAX_UNSIGNED;
    return val > max;
  }

  // Return true if VAL (stored in a uint64_t) has overflowed both a
  // signed and an unsigned value.  E.g.,
  // Bits<8>::has_signed_unsigned_overflow would check -128 <= VAL <
  // 255.
  static inline bool
  has_signed_unsigned_overflow64(uint64_t val)
  {
    gold_assert(bits > 0 && bits <= 64);
    if (bits == 64)
      return false;
    const int64_t max = static_cast<int64_t>(Limits<bits>::MAX_UNSIGNED);
    const int64_t min = Limits<bits>::MIN_SIGNED;
    int64_t as_signed = static_cast<int64_t>(val);
    return as_signed > max || as_signed < min;
  }

  // Select bits from A and B using bits in MASK.  For each n in
  // [0..31], the n-th bit in the result is chosen from the n-th bits
  // of A and B.  A zero selects A and a one selects B.
  static inline uint64_t
  bit_select64(uint64_t a, uint64_t b, uint64_t mask)
  { return (a & ~mask) | (b & mask); }
};

// Track relocations while reading a section.  This lets you ask for
// the relocation at a certain offset, and see how relocs occur
// between points of interest.

template<int size, bool big_endian>
class Track_relocs
{
 public:
  Track_relocs()
    : prelocs_(NULL), len_(0), pos_(0), reloc_size_(0)
  { }

  // Initialize the Track_relocs object.  OBJECT is the object holding
  // the reloc section, RELOC_SHNDX is the section index of the reloc
  // section, and RELOC_TYPE is the type of the reloc section
  // (elfcpp::SHT_REL or elfcpp::SHT_RELA).  This returns false if
  // something went wrong.
  bool
  initialize(Object* object, unsigned int reloc_shndx,
	     unsigned int reloc_type);

  // Return the offset in the data section to which the next reloc
  // applies.  This returns -1 if there is no next reloc.
  off_t
  next_offset() const;

  // Return the symbol index of the next reloc.  This returns -1U if
  // there is no next reloc.
  unsigned int
  next_symndx() const;

  // Return the addend of the next reloc.  This returns 0 if there is
  // no next reloc.
  uint64_t
  next_addend() const;

  // Advance to OFFSET within the data section, and return the number
  // of relocs which would be skipped.
  int
  advance(off_t offset);

  // Checkpoint the current position in the reloc section.
  section_size_type
  checkpoint() const
  { return this->pos_; }

  // Reset the position to CHECKPOINT.
  void
  reset(section_size_type checkpoint)
  { this->pos_ = checkpoint; }

 private:
  // The contents of the input object's reloc section.
  const unsigned char* prelocs_;
  // The length of the reloc section.
  section_size_type len_;
  // Our current position in the reloc section.
  section_size_type pos_;
  // The size of the relocs in the section.
  int reloc_size_;
};

} // End namespace gold.

#endif // !defined(GOLD_RELOC_H)