aboutsummaryrefslogtreecommitdiff
path: root/gold/reloc.h
blob: fb6c8460b4398264794d1a2c5fc213f22fa8cc76 (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
// reloc.h -- relocate input files for gold   -*- C++ -*-

// Copyright 2006, 2007 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>
#include <byteswap.h>

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

namespace gold
{

class General_options;
class Object;
class Relobj;
class 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;

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:
  // SYMTAB_LOCK is used to lock the symbol table.  BLOCKER should be
  // unblocked when the Scan_relocs task completes.
  Read_relocs(const General_options& options, Symbol_table* symtab,
	      Layout* layout, Relobj* object, Task_token* symtab_lock,
	      Task_token* blocker)
    : options_(options), symtab_(symtab), layout_(layout), object_(object),
      symtab_lock_(symtab_lock), blocker_(blocker)
  { }

  // The standard Task methods.

  Task_token*
  is_runnable();

  void
  locks(Task_locker*);

  void
  run(Workqueue*);

  std::string
  get_name() const;

 private:
  const General_options& options_;
  Symbol_table* symtab_;
  Layout* layout_;
  Relobj* object_;
  Task_token* symtab_lock_;
  Task_token* blocker_;
};

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

class Scan_relocs : public Task
{
 public:
  // SYMTAB_LOCK is used to lock the symbol table.  BLOCKER should be
  // unblocked when the task completes.
  Scan_relocs(const General_options& options, Symbol_table* symtab,
	      Layout* layout, Relobj* object, Read_relocs_data* rd,
	      Task_token* symtab_lock, Task_token* blocker)
    : options_(options), symtab_(symtab), layout_(layout), object_(object),
      rd_(rd), symtab_lock_(symtab_lock), blocker_(blocker)
  { }

  // The standard Task methods.

  Task_token*
  is_runnable();

  void
  locks(Task_locker*);

  void
  run(Workqueue*);

  std::string
  get_name() const;

 private:
  const General_options& options_;
  Symbol_table* symtab_;
  Layout* layout_;
  Relobj* object_;
  Read_relocs_data* rd_;
  Task_token* symtab_lock_;
  Task_token* blocker_;
};

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

class Relocate_task : public Task
{
 public:
  Relocate_task(const General_options& options, 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)
    : options_(options), 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 General_options& options_;
  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,
    // 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]);
  }

  // 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_;
};

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

  // 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 void
  rel(unsigned char* view,
      const Sized_relobj<size, big_endian>* object,
      const Symbol_value<size>* psymval)
  {
    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
    Valtype* wv = reinterpret_cast<Valtype*>(view);
    Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv);
    x = psymval->value(object, x);
    elfcpp::Swap<valsize, big_endian>::writeval(wv, x);
  }

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

  // 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 void
  rela(unsigned char* view,
       const Sized_relobj<size, big_endian>* object,
       const Symbol_value<size>* psymval,
       typename elfcpp::Swap<valsize, big_endian>::Valtype addend)
  {
    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
    Valtype* wv = reinterpret_cast<Valtype*>(view);
    Valtype x = psymval->value(object, addend);
    elfcpp::Swap<valsize, big_endian>::writeval(wv, x);
  }

  // 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 void
  pcrel(unsigned char* view,
	typename elfcpp::Swap<valsize, big_endian>::Valtype value,
	typename elfcpp::Elf_types<size>::Elf_Addr address)
  {
    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
    Valtype* wv = reinterpret_cast<Valtype*>(view);
    Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv);
    elfcpp::Swap<valsize, big_endian>::writeval(wv, x + value - address);
  }

  // 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 void
  pcrel(unsigned char* view,
	const Sized_relobj<size, big_endian>* object,
	const Symbol_value<size>* psymval,
	typename elfcpp::Elf_types<size>::Elf_Addr address)
  {
    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
    Valtype* wv = reinterpret_cast<Valtype*>(view);
    Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv);
    x = psymval->value(object, x);
    elfcpp::Swap<valsize, big_endian>::writeval(wv, x - address);
  }

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

  // 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 void
  pcrela(unsigned char* view,
	 const Sized_relobj<size, big_endian>* object,
	 const Symbol_value<size>* psymval,
	 typename elfcpp::Swap<valsize, big_endian>::Valtype addend,
	 typename elfcpp::Elf_types<size>::Elf_Addr address)
  {
    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
    Valtype* wv = reinterpret_cast<Valtype*>(view);
    Valtype x = psymval->value(object, addend);
    elfcpp::Swap<valsize, big_endian>::writeval(wv, x - address);
  }

  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, unsigned char value)
  { This::template rel<8>(view, value); }

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

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

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

  // 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,
	 typename elfcpp::Elf_types<size>::Elf_Addr address)
  { This::template pcrel<8>(view, value, address); }

  static inline void
  pcrel8(unsigned char* view,
	 const Sized_relobj<size, big_endian>* object,
	 const Symbol_value<size>* psymval,
	 typename elfcpp::Elf_types<size>::Elf_Addr address)
  { This::template pcrel<8>(view, object, psymval, address); }

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

  static inline void
  pcrela8(unsigned char* view,
	  const Sized_relobj<size, big_endian>* object,
	  const Symbol_value<size>* psymval,
	  unsigned char addend,
	  typename elfcpp::Elf_types<size>::Elf_Addr address)
  { This::template pcrela<8>(view, object, psymval, addend, address); }

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

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

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

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

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

  static inline void
  pcrel16(unsigned char* view,
	  const Sized_relobj<size, big_endian>* object,
	  const Symbol_value<size>* psymval,
	  typename elfcpp::Elf_types<size>::Elf_Addr address)
  { This::template pcrel<16>(view, object, psymval, address); }

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

  static inline void
  pcrela16(unsigned char* view,
	   const Sized_relobj<size, big_endian>* object,
	   const Symbol_value<size>* psymval,
	   elfcpp::Elf_Half addend,
	   typename elfcpp::Elf_types<size>::Elf_Addr address)
  { This::template pcrela<16>(view, object, psymval, addend, address); }

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

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

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

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

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

  static inline void
  pcrel32(unsigned char* view,
	  const Sized_relobj<size, big_endian>* object,
	  const Symbol_value<size>* psymval,
	  typename elfcpp::Elf_types<size>::Elf_Addr address)
  { This::template pcrel<32>(view, object, psymval, address); }

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

  static inline void
  pcrela32(unsigned char* view,
	   const Sized_relobj<size, big_endian>* object,
	   const Symbol_value<size>* psymval,
	   elfcpp::Elf_Word addend,
	   typename elfcpp::Elf_types<size>::Elf_Addr address)
  { This::template pcrela<32>(view, object, psymval, addend, address); }

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

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

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

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

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

  static inline void
  pcrel64(unsigned char* view,
	  const Sized_relobj<size, big_endian>* object,
	  const Symbol_value<size>* psymval,
	  typename elfcpp::Elf_types<size>::Elf_Addr address)
  { This::template pcrel<64>(view, object, psymval, address); }

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

  static inline void
  pcrela64(unsigned char* view,
	   const Sized_relobj<size, big_endian>* object,
	   const Symbol_value<size>* psymval,
	   elfcpp::Elf_Xword addend,
	   typename elfcpp::Elf_types<size>::Elf_Addr address)
  { This::template pcrela<64>(view, object, psymval, addend, address); }
};

// We try to avoid COPY relocations when possible.  A COPY relocation
// may be required when an executable refers to a variable defined in
// a shared library.  COPY relocations are problematic because they
// tie the executable to the exact size of the variable in the shared
// library.  We can avoid them if all the references to the variable
// are in a writeable section.  In that case we can simply use dynamic
// relocations.  However, when scanning relocs, we don't know when we
// see the relocation whether we will be forced to use a COPY
// relocation or not.  So we have to save the relocation during the
// reloc scanning, and then emit it as a dynamic relocation if
// necessary.  This class implements that.  It is used by the target
// specific code.

template<int size, bool big_endian>
class Copy_relocs
{
 public:
  Copy_relocs()
    : entries_()
  { }

  // Return whether we need a COPY reloc for a reloc against GSYM,
  // which is being applied to section SHNDX in OBJECT.
  static bool
  need_copy_reloc(const General_options*, Relobj* object, unsigned int shndx,
		  Sized_symbol<size>* gsym);

  // Save a Rel against SYM for possible emission later.  SHNDX is the
  // index of the section to which the reloc is being applied.
  void
  save(Symbol* sym, Relobj*, unsigned int shndx,
       Output_section* output_section, const elfcpp::Rel<size, big_endian>&);

  // Save a Rela against SYM for possible emission later.
  void
  save(Symbol* sym, Relobj*, unsigned int shndx,
       Output_section* output_section, const elfcpp::Rela<size, big_endian>&);

  // Return whether there are any relocs to emit.  This also discards
  // entries which need not be emitted.
  bool
  any_to_emit();

  // Emit relocs for each symbol which did not get a COPY reloc (i.e.,
  // is still defined in the dynamic object).
  template<int sh_type>
  void
  emit(Output_data_reloc<sh_type, true, size, big_endian>*);

 private:
  typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
  typedef typename elfcpp::Elf_types<size>::Elf_Addr Addend;

  // This POD class holds the entries we are saving.
  class Copy_reloc_entry
  {
   public:
    Copy_reloc_entry(Symbol* sym, unsigned int reloc_type,
		     Relobj* relobj, unsigned int shndx,
		     Output_section* output_section,
		     Address address, Addend addend)
      : sym_(sym), reloc_type_(reloc_type), relobj_(relobj),
	shndx_(shndx), output_section_(output_section),
	address_(address), addend_(addend)
    { }

    // Return whether we should emit this reloc.  If we should not
    // emit, we clear it.
    bool
    should_emit();

    // Emit this reloc.

    void
    emit(Output_data_reloc<elfcpp::SHT_REL, true, size, big_endian>*);

    void
    emit(Output_data_reloc<elfcpp::SHT_RELA, true, size, big_endian>*);

   private:
    Symbol* sym_;
    unsigned int reloc_type_;
    Relobj* relobj_;
    unsigned int shndx_;
    Output_section* output_section_;
    Address address_;
    Addend addend_;
  };

  // A list of relocs to be saved.
  typedef std::vector<Copy_reloc_entry> Copy_reloc_entries;

  // The list of relocs we are saving.
  Copy_reloc_entries entries_;
};

// 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;

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

 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)