* reloc.cc (Sized_relobj::do_read_relocs): Use constant invalid_address
[external/binutils.git] / gold / reloc.cc
1 // reloc.cc -- relocate input files for gold.
2
3 // Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
5
6 // This file is part of gold.
7
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
12
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 // GNU General Public License for more details.
17
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
22
23 #include "gold.h"
24
25 #include <algorithm>
26
27 #include "workqueue.h"
28 #include "symtab.h"
29 #include "output.h"
30 #include "merge.h"
31 #include "object.h"
32 #include "target-reloc.h"
33 #include "reloc.h"
34
35 namespace gold
36 {
37
38 // Read_relocs methods.
39
40 // These tasks just read the relocation information from the file.
41 // After reading it, the start another task to process the
42 // information.  These tasks requires access to the file.
43
44 Task_token*
45 Read_relocs::is_runnable()
46 {
47   return this->object_->is_locked() ? this->object_->token() : NULL;
48 }
49
50 // Lock the file.
51
52 void
53 Read_relocs::locks(Task_locker* tl)
54 {
55   tl->add(this, this->object_->token());
56 }
57
58 // Read the relocations and then start a Scan_relocs_task.
59
60 void
61 Read_relocs::run(Workqueue* workqueue)
62 {
63   Read_relocs_data *rd = new Read_relocs_data;
64   this->object_->read_relocs(rd);
65   this->object_->release();
66
67   workqueue->queue_next(new Scan_relocs(this->options_, this->symtab_,
68                                         this->layout_, this->object_, rd,
69                                         this->symtab_lock_, this->blocker_));
70 }
71
72 // Return a debugging name for the task.
73
74 std::string
75 Read_relocs::get_name() const
76 {
77   return "Read_relocs " + this->object_->name();
78 }
79
80 // Scan_relocs methods.
81
82 // These tasks scan the relocations read by Read_relocs and mark up
83 // the symbol table to indicate which relocations are required.  We
84 // use a lock on the symbol table to keep them from interfering with
85 // each other.
86
87 Task_token*
88 Scan_relocs::is_runnable()
89 {
90   if (!this->symtab_lock_->is_writable())
91     return this->symtab_lock_;
92   if (this->object_->is_locked())
93     return this->object_->token();
94   return NULL;
95 }
96
97 // Return the locks we hold: one on the file, one on the symbol table
98 // and one blocker.
99
100 void
101 Scan_relocs::locks(Task_locker* tl)
102 {
103   tl->add(this, this->object_->token());
104   tl->add(this, this->symtab_lock_);
105   tl->add(this, this->blocker_);
106 }
107
108 // Scan the relocs.
109
110 void
111 Scan_relocs::run(Workqueue*)
112 {
113   this->object_->scan_relocs(this->options_, this->symtab_, this->layout_,
114                              this->rd_);
115   this->object_->release();
116   delete this->rd_;
117   this->rd_ = NULL;
118 }
119
120 // Return a debugging name for the task.
121
122 std::string
123 Scan_relocs::get_name() const
124 {
125   return "Scan_relocs " + this->object_->name();
126 }
127
128 // Relocate_task methods.
129
130 // We may have to wait for the output sections to be written.
131
132 Task_token*
133 Relocate_task::is_runnable()
134 {
135   if (this->object_->relocs_must_follow_section_writes()
136       && this->output_sections_blocker_->is_blocked())
137     return this->output_sections_blocker_;
138
139   if (this->object_->is_locked())
140     return this->object_->token();
141
142   return NULL;
143 }
144
145 // We want to lock the file while we run.  We want to unblock
146 // INPUT_SECTIONS_BLOCKER and FINAL_BLOCKER when we are done.
147 // INPUT_SECTIONS_BLOCKER may be NULL.
148
149 void
150 Relocate_task::locks(Task_locker* tl)
151 {
152   if (this->input_sections_blocker_ != NULL)
153     tl->add(this, this->input_sections_blocker_);
154   tl->add(this, this->final_blocker_);
155   tl->add(this, this->object_->token());
156 }
157
158 // Run the task.
159
160 void
161 Relocate_task::run(Workqueue*)
162 {
163   this->object_->relocate(this->options_, this->symtab_, this->layout_,
164                           this->of_);
165
166   // This is normally the last thing we will do with an object, so
167   // uncache all views.
168   this->object_->clear_view_cache_marks();
169
170   this->object_->release();
171 }
172
173 // Return a debugging name for the task.
174
175 std::string
176 Relocate_task::get_name() const
177 {
178   return "Relocate_task " + this->object_->name();
179 }
180
181 // Read the relocs and local symbols from the object file and store
182 // the information in RD.
183
184 template<int size, bool big_endian>
185 void
186 Sized_relobj<size, big_endian>::do_read_relocs(Read_relocs_data* rd)
187 {
188   rd->relocs.clear();
189
190   unsigned int shnum = this->shnum();
191   if (shnum == 0)
192     return;
193
194   rd->relocs.reserve(shnum / 2);
195
196   const Output_sections& out_sections(this->output_sections());
197   const std::vector<Address>& out_offsets(this->section_offsets_);
198
199   const unsigned char *pshdrs = this->get_view(this->elf_file_.shoff(),
200                                                shnum * This::shdr_size,
201                                                true, true);
202   // Skip the first, dummy, section.
203   const unsigned char *ps = pshdrs + This::shdr_size;
204   for (unsigned int i = 1; i < shnum; ++i, ps += This::shdr_size)
205     {
206       typename This::Shdr shdr(ps);
207
208       unsigned int sh_type = shdr.get_sh_type();
209       if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
210         continue;
211
212       unsigned int shndx = this->adjust_shndx(shdr.get_sh_info());
213       if (shndx >= shnum)
214         {
215           this->error(_("relocation section %u has bad info %u"),
216                       i, shndx);
217           continue;
218         }
219
220       Output_section* os = out_sections[shndx];
221       if (os == NULL)
222         continue;
223
224       // We are scanning relocations in order to fill out the GOT and
225       // PLT sections.  Relocations for sections which are not
226       // allocated (typically debugging sections) should not add new
227       // GOT and PLT entries.  So we skip them unless this is a
228       // relocatable link or we need to emit relocations.
229       typename This::Shdr secshdr(pshdrs + shndx * This::shdr_size);
230       bool is_section_allocated = ((secshdr.get_sh_flags() & elfcpp::SHF_ALLOC)
231                                    != 0);
232       if (!is_section_allocated
233           && !parameters->options().relocatable()
234           && !parameters->options().emit_relocs())
235         continue;
236
237       if (this->adjust_shndx(shdr.get_sh_link()) != this->symtab_shndx_)
238         {
239           this->error(_("relocation section %u uses unexpected "
240                         "symbol table %u"),
241                       i, this->adjust_shndx(shdr.get_sh_link()));
242           continue;
243         }
244
245       off_t sh_size = shdr.get_sh_size();
246
247       unsigned int reloc_size;
248       if (sh_type == elfcpp::SHT_REL)
249         reloc_size = elfcpp::Elf_sizes<size>::rel_size;
250       else
251         reloc_size = elfcpp::Elf_sizes<size>::rela_size;
252       if (reloc_size != shdr.get_sh_entsize())
253         {
254           this->error(_("unexpected entsize for reloc section %u: %lu != %u"),
255                       i, static_cast<unsigned long>(shdr.get_sh_entsize()),
256                       reloc_size);
257           continue;
258         }
259
260       size_t reloc_count = sh_size / reloc_size;
261       if (static_cast<off_t>(reloc_count * reloc_size) != sh_size)
262         {
263           this->error(_("reloc section %u size %lu uneven"),
264                       i, static_cast<unsigned long>(sh_size));
265           continue;
266         }
267
268       rd->relocs.push_back(Section_relocs());
269       Section_relocs& sr(rd->relocs.back());
270       sr.reloc_shndx = i;
271       sr.data_shndx = shndx;
272       sr.contents = this->get_lasting_view(shdr.get_sh_offset(), sh_size,
273                                            true, true);
274       sr.sh_type = sh_type;
275       sr.reloc_count = reloc_count;
276       sr.output_section = os;
277       sr.needs_special_offset_handling = out_offsets[shndx] == invalid_address;
278       sr.is_data_section_allocated = is_section_allocated;
279     }
280
281   // Read the local symbols.
282   gold_assert(this->symtab_shndx_ != -1U);
283   if (this->symtab_shndx_ == 0 || this->local_symbol_count_ == 0)
284     rd->local_symbols = NULL;
285   else
286     {
287       typename This::Shdr symtabshdr(pshdrs
288                                      + this->symtab_shndx_ * This::shdr_size);
289       gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
290       const int sym_size = This::sym_size;
291       const unsigned int loccount = this->local_symbol_count_;
292       gold_assert(loccount == symtabshdr.get_sh_info());
293       off_t locsize = loccount * sym_size;
294       rd->local_symbols = this->get_lasting_view(symtabshdr.get_sh_offset(),
295                                                  locsize, true, true);
296     }
297 }
298
299 // Scan the relocs and adjust the symbol table.  This looks for
300 // relocations which require GOT/PLT/COPY relocations.
301
302 template<int size, bool big_endian>
303 void
304 Sized_relobj<size, big_endian>::do_scan_relocs(const General_options& options,
305                                                Symbol_table* symtab,
306                                                Layout* layout,
307                                                Read_relocs_data* rd)
308 {
309   Sized_target<size, big_endian>* target = this->sized_target();
310
311   const unsigned char* local_symbols;
312   if (rd->local_symbols == NULL)
313     local_symbols = NULL;
314   else
315     local_symbols = rd->local_symbols->data();
316
317   for (Read_relocs_data::Relocs_list::iterator p = rd->relocs.begin();
318        p != rd->relocs.end();
319        ++p)
320     {
321       if (!parameters->options().relocatable())
322         {
323           // As noted above, when not generating an object file, we
324           // only scan allocated sections.  We may see a non-allocated
325           // section here if we are emitting relocs.
326           if (p->is_data_section_allocated)
327             target->scan_relocs(options, symtab, layout, this, p->data_shndx,
328                                 p->sh_type, p->contents->data(),
329                                 p->reloc_count, p->output_section,
330                                 p->needs_special_offset_handling,
331                                 this->local_symbol_count_,
332                                 local_symbols);
333           if (parameters->options().emit_relocs())
334             this->emit_relocs_scan(options, symtab, layout, local_symbols, p);
335         }
336       else
337         {
338           Relocatable_relocs* rr = this->relocatable_relocs(p->reloc_shndx);
339           gold_assert(rr != NULL);
340           rr->set_reloc_count(p->reloc_count);
341           target->scan_relocatable_relocs(options, symtab, layout, this,
342                                           p->data_shndx, p->sh_type,
343                                           p->contents->data(),
344                                           p->reloc_count,
345                                           p->output_section,
346                                           p->needs_special_offset_handling,
347                                           this->local_symbol_count_,
348                                           local_symbols,
349                                           rr);
350         }
351
352       delete p->contents;
353       p->contents = NULL;
354     }
355
356   if (rd->local_symbols != NULL)
357     {
358       delete rd->local_symbols;
359       rd->local_symbols = NULL;
360     }
361 }
362
363 // This is a strategy class we use when scanning for --emit-relocs.
364
365 template<int sh_type>
366 class Emit_relocs_strategy
367 {
368  public:
369   // A local non-section symbol.
370   inline Relocatable_relocs::Reloc_strategy
371   local_non_section_strategy(unsigned int, Relobj*)
372   { return Relocatable_relocs::RELOC_COPY; }
373
374   // A local section symbol.
375   inline Relocatable_relocs::Reloc_strategy
376   local_section_strategy(unsigned int, Relobj*)
377   {
378     if (sh_type == elfcpp::SHT_RELA)
379       return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA;
380     else
381       {
382         // The addend is stored in the section contents.  Since this
383         // is not a relocatable link, we are going to apply the
384         // relocation contents to the section as usual.  This means
385         // that we have no way to record the original addend.  If the
386         // original addend is not zero, there is basically no way for
387         // the user to handle this correctly.  Caveat emptor.
388         return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0;
389       }
390   }
391
392   // A global symbol.
393   inline Relocatable_relocs::Reloc_strategy
394   global_strategy(unsigned int, Relobj*, unsigned int)
395   { return Relocatable_relocs::RELOC_COPY; }
396 };
397
398 // Scan the input relocations for --emit-relocs.
399
400 template<int size, bool big_endian>
401 void
402 Sized_relobj<size, big_endian>::emit_relocs_scan(
403     const General_options& options,
404     Symbol_table* symtab,
405     Layout* layout,
406     const unsigned char* plocal_syms,
407     const Read_relocs_data::Relocs_list::iterator& p)
408 {
409   Relocatable_relocs* rr = this->relocatable_relocs(p->reloc_shndx);
410   gold_assert(rr != NULL);
411   rr->set_reloc_count(p->reloc_count);
412
413   if (p->sh_type == elfcpp::SHT_REL)
414     this->emit_relocs_scan_reltype<elfcpp::SHT_REL>(options, symtab, layout,
415                                                     plocal_syms, p, rr);
416   else
417     {
418       gold_assert(p->sh_type == elfcpp::SHT_RELA);
419       this->emit_relocs_scan_reltype<elfcpp::SHT_RELA>(options, symtab,
420                                                        layout, plocal_syms, p,
421                                                        rr);
422     }
423 }
424
425 // Scan the input relocation for --emit-relocs, templatized on the
426 // type of the relocation section.
427
428 template<int size, bool big_endian>
429 template<int sh_type>
430 void
431 Sized_relobj<size, big_endian>::emit_relocs_scan_reltype(
432     const General_options& options,
433     Symbol_table* symtab,
434     Layout* layout,
435     const unsigned char* plocal_syms,
436     const Read_relocs_data::Relocs_list::iterator& p,
437     Relocatable_relocs* rr)
438 {
439   scan_relocatable_relocs<size, big_endian, sh_type,
440                           Emit_relocs_strategy<sh_type> >(
441     options,
442     symtab,
443     layout,
444     this,
445     p->data_shndx,
446     p->contents->data(),
447     p->reloc_count,
448     p->output_section,
449     p->needs_special_offset_handling,
450     this->local_symbol_count_,
451     plocal_syms,
452     rr);
453 }
454
455 // Relocate the input sections and write out the local symbols.
456
457 template<int size, bool big_endian>
458 void
459 Sized_relobj<size, big_endian>::do_relocate(const General_options& options,
460                                             const Symbol_table* symtab,
461                                             const Layout* layout,
462                                             Output_file* of)
463 {
464   unsigned int shnum = this->shnum();
465
466   // Read the section headers.
467   const unsigned char* pshdrs = this->get_view(this->elf_file_.shoff(),
468                                                shnum * This::shdr_size,
469                                                true, true);
470
471   Views views;
472   views.resize(shnum);
473
474   // Make two passes over the sections.  The first one copies the
475   // section data to the output file.  The second one applies
476   // relocations.
477
478   this->write_sections(pshdrs, of, &views);
479
480   // To speed up relocations, we set up hash tables for fast lookup of
481   // input offsets to output addresses.
482   this->initialize_input_to_output_maps();
483
484   // Apply relocations.
485
486   this->relocate_sections(options, symtab, layout, pshdrs, &views);
487
488   // After we've done the relocations, we release the hash tables,
489   // since we no longer need them.
490   this->free_input_to_output_maps();
491
492   // Write out the accumulated views.
493   for (unsigned int i = 1; i < shnum; ++i)
494     {
495       if (views[i].view != NULL)
496         {
497           if (!views[i].is_postprocessing_view)
498             {
499               if (views[i].is_input_output_view)
500                 of->write_input_output_view(views[i].offset,
501                                             views[i].view_size,
502                                             views[i].view);
503               else
504                 of->write_output_view(views[i].offset, views[i].view_size,
505                                       views[i].view);
506             }
507         }
508     }
509
510   // Write out the local symbols.
511   this->write_local_symbols(of, layout->sympool(), layout->dynpool(),
512                             layout->symtab_xindex(), layout->dynsym_xindex());
513
514   // We should no longer need the local symbol values.
515   this->clear_local_symbols();
516 }
517
518 // Sort a Read_multiple vector by file offset.
519 struct Read_multiple_compare
520 {
521   inline bool
522   operator()(const File_read::Read_multiple_entry& rme1,
523              const File_read::Read_multiple_entry& rme2) const
524   { return rme1.file_offset < rme2.file_offset; }
525 };
526
527 // Write section data to the output file.  PSHDRS points to the
528 // section headers.  Record the views in *PVIEWS for use when
529 // relocating.
530
531 template<int size, bool big_endian>
532 void
533 Sized_relobj<size, big_endian>::write_sections(const unsigned char* pshdrs,
534                                                Output_file* of,
535                                                Views* pviews)
536 {
537   unsigned int shnum = this->shnum();
538   const Output_sections& out_sections(this->output_sections());
539   const std::vector<Address>& out_offsets(this->section_offsets_);
540
541   File_read::Read_multiple rm;
542   bool is_sorted = true;
543
544   const unsigned char* p = pshdrs + This::shdr_size;
545   for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
546     {
547       View_size* pvs = &(*pviews)[i];
548
549       pvs->view = NULL;
550
551       const Output_section* os = out_sections[i];
552       if (os == NULL)
553         continue;
554       Address output_offset = out_offsets[i];
555
556       typename This::Shdr shdr(p);
557
558       if (shdr.get_sh_type() == elfcpp::SHT_NOBITS)
559         continue;
560
561       if ((parameters->options().relocatable()
562            || parameters->options().emit_relocs())
563           && (shdr.get_sh_type() == elfcpp::SHT_REL
564               || shdr.get_sh_type() == elfcpp::SHT_RELA)
565           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
566         {
567           // This is a reloc section in a relocatable link or when
568           // emitting relocs.  We don't need to read the input file.
569           // The size and file offset are stored in the
570           // Relocatable_relocs structure.
571           Relocatable_relocs* rr = this->relocatable_relocs(i);
572           gold_assert(rr != NULL);
573           Output_data* posd = rr->output_data();
574           gold_assert(posd != NULL);
575
576           pvs->offset = posd->offset();
577           pvs->view_size = posd->data_size();
578           pvs->view = of->get_output_view(pvs->offset, pvs->view_size);
579           pvs->address = posd->address();
580           pvs->is_input_output_view = false;
581           pvs->is_postprocessing_view = false;
582
583           continue;
584         }
585
586       // In the normal case, this input section is simply mapped to
587       // the output section at offset OUTPUT_OFFSET.
588
589       // However, if OUTPUT_OFFSET == INVALID_ADDRESS, then input data is
590       // handled specially--e.g., a .eh_frame section.  The relocation
591       // routines need to check for each reloc where it should be
592       // applied.  For this case, we need an input/output view for the
593       // entire contents of the section in the output file.  We don't
594       // want to copy the contents of the input section to the output
595       // section; the output section contents were already written,
596       // and we waited for them in Relocate_task::is_runnable because
597       // relocs_must_follow_section_writes is set for the object.
598
599       // Regardless of which of the above cases is true, we have to
600       // check requires_postprocessing of the output section.  If that
601       // is false, then we work with views of the output file
602       // directly.  If it is true, then we work with a separate
603       // buffer, and the output section is responsible for writing the
604       // final data to the output file.
605
606       off_t output_section_offset;
607       Address output_section_size;
608       if (!os->requires_postprocessing())
609         {
610           output_section_offset = os->offset();
611           output_section_size = convert_types<Address, off_t>(os->data_size());
612         }
613       else
614         {
615           output_section_offset = 0;
616           output_section_size =
617               convert_types<Address, off_t>(os->postprocessing_buffer_size());
618         }
619
620       off_t view_start;
621       section_size_type view_size;
622       if (output_offset != invalid_address)
623         {
624           view_start = output_section_offset + output_offset;
625           view_size = convert_to_section_size_type(shdr.get_sh_size());
626         }
627       else
628         {
629           view_start = output_section_offset;
630           view_size = convert_to_section_size_type(output_section_size);
631         }
632
633       if (view_size == 0)
634         continue;
635
636       gold_assert(output_offset == invalid_address
637                   || output_offset + view_size <= output_section_size);
638
639       unsigned char* view;
640       if (os->requires_postprocessing())
641         {
642           unsigned char* buffer = os->postprocessing_buffer();
643           view = buffer + view_start;
644           if (output_offset != invalid_address)
645             {
646               off_t sh_offset = shdr.get_sh_offset();
647               if (!rm.empty() && rm.back().file_offset > sh_offset)
648                 is_sorted = false;
649               rm.push_back(File_read::Read_multiple_entry(sh_offset,
650                                                           view_size, view));
651             }
652         }
653       else
654         {
655           if (output_offset == invalid_address)
656             view = of->get_input_output_view(view_start, view_size);
657           else
658             {
659               view = of->get_output_view(view_start, view_size);
660               off_t sh_offset = shdr.get_sh_offset();
661               if (!rm.empty() && rm.back().file_offset > sh_offset)
662                 is_sorted = false;
663               rm.push_back(File_read::Read_multiple_entry(sh_offset,
664                                                           view_size, view));
665             }
666         }
667
668       pvs->view = view;
669       pvs->address = os->address();
670       if (output_offset != invalid_address)
671         pvs->address += output_offset;
672       pvs->offset = view_start;
673       pvs->view_size = view_size;
674       pvs->is_input_output_view = output_offset == invalid_address;
675       pvs->is_postprocessing_view = os->requires_postprocessing();
676     }
677
678   // Actually read the data.
679   if (!rm.empty())
680     {
681       if (!is_sorted)
682         std::sort(rm.begin(), rm.end(), Read_multiple_compare());
683       this->read_multiple(rm);
684     }
685 }
686
687 // Relocate section data.  VIEWS points to the section data as views
688 // in the output file.
689
690 template<int size, bool big_endian>
691 void
692 Sized_relobj<size, big_endian>::relocate_sections(
693     const General_options& options,
694     const Symbol_table* symtab,
695     const Layout* layout,
696     const unsigned char* pshdrs,
697     Views* pviews)
698 {
699   unsigned int shnum = this->shnum();
700   Sized_target<size, big_endian>* target = this->sized_target();
701
702   const Output_sections& out_sections(this->output_sections());
703   const std::vector<Address>& out_offsets(this->section_offsets_);
704
705   Relocate_info<size, big_endian> relinfo;
706   relinfo.options = &options;
707   relinfo.symtab = symtab;
708   relinfo.layout = layout;
709   relinfo.object = this;
710
711   const unsigned char* p = pshdrs + This::shdr_size;
712   for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
713     {
714       typename This::Shdr shdr(p);
715
716       unsigned int sh_type = shdr.get_sh_type();
717       if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
718         continue;
719
720       unsigned int index = this->adjust_shndx(shdr.get_sh_info());
721       if (index >= this->shnum())
722         {
723           this->error(_("relocation section %u has bad info %u"),
724                       i, index);
725           continue;
726         }
727
728       Output_section* os = out_sections[index];
729       if (os == NULL)
730         {
731           // This relocation section is against a section which we
732           // discarded.
733           continue;
734         }
735       Address output_offset = out_offsets[index];
736
737       gold_assert((*pviews)[index].view != NULL);
738       if (parameters->options().relocatable())
739         gold_assert((*pviews)[i].view != NULL);
740
741       if (this->adjust_shndx(shdr.get_sh_link()) != this->symtab_shndx_)
742         {
743           gold_error(_("relocation section %u uses unexpected "
744                        "symbol table %u"),
745                      i, this->adjust_shndx(shdr.get_sh_link()));
746           continue;
747         }
748
749       off_t sh_size = shdr.get_sh_size();
750       const unsigned char* prelocs = this->get_view(shdr.get_sh_offset(),
751                                                     sh_size, true, false);
752
753       unsigned int reloc_size;
754       if (sh_type == elfcpp::SHT_REL)
755         reloc_size = elfcpp::Elf_sizes<size>::rel_size;
756       else
757         reloc_size = elfcpp::Elf_sizes<size>::rela_size;
758
759       if (reloc_size != shdr.get_sh_entsize())
760         {
761           gold_error(_("unexpected entsize for reloc section %u: %lu != %u"),
762                      i, static_cast<unsigned long>(shdr.get_sh_entsize()),
763                      reloc_size);
764           continue;
765         }
766
767       size_t reloc_count = sh_size / reloc_size;
768       if (static_cast<off_t>(reloc_count * reloc_size) != sh_size)
769         {
770           gold_error(_("reloc section %u size %lu uneven"),
771                      i, static_cast<unsigned long>(sh_size));
772           continue;
773         }
774
775       gold_assert(output_offset != invalid_address
776                   || this->relocs_must_follow_section_writes());
777
778       relinfo.reloc_shndx = i;
779       relinfo.data_shndx = index;
780       if (!parameters->options().relocatable())
781         {
782           target->relocate_section(&relinfo,
783                                    sh_type,
784                                    prelocs,
785                                    reloc_count,
786                                    os,
787                                    output_offset == invalid_address,
788                                    (*pviews)[index].view,
789                                    (*pviews)[index].address,
790                                    (*pviews)[index].view_size);
791           if (parameters->options().emit_relocs())
792             this->emit_relocs(&relinfo, i, sh_type, prelocs, reloc_count,
793                               os, output_offset,
794                               (*pviews)[index].view,
795                               (*pviews)[index].address,
796                               (*pviews)[index].view_size,
797                               (*pviews)[i].view,
798                               (*pviews)[i].view_size);
799         }
800       else
801         {
802           Relocatable_relocs* rr = this->relocatable_relocs(i);
803           target->relocate_for_relocatable(&relinfo,
804                                            sh_type,
805                                            prelocs,
806                                            reloc_count,
807                                            os,
808                                            output_offset,
809                                            rr,
810                                            (*pviews)[index].view,
811                                            (*pviews)[index].address,
812                                            (*pviews)[index].view_size,
813                                            (*pviews)[i].view,
814                                            (*pviews)[i].view_size);
815         }
816     }
817 }
818
819 // Emit the relocs for --emit-relocs.
820
821 template<int size, bool big_endian>
822 void
823 Sized_relobj<size, big_endian>::emit_relocs(
824     const Relocate_info<size, big_endian>* relinfo,
825     unsigned int i,
826     unsigned int sh_type,
827     const unsigned char* prelocs,
828     size_t reloc_count,
829     Output_section* output_section,
830     typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
831     unsigned char* view,
832     typename elfcpp::Elf_types<size>::Elf_Addr address,
833     section_size_type view_size,
834     unsigned char* reloc_view,
835     section_size_type reloc_view_size)
836 {
837   if (sh_type == elfcpp::SHT_REL)
838     this->emit_relocs_reltype<elfcpp::SHT_REL>(relinfo, i, prelocs,
839                                                reloc_count, output_section,
840                                                offset_in_output_section,
841                                                view, address, view_size,
842                                                reloc_view, reloc_view_size);
843   else
844     {
845       gold_assert(sh_type == elfcpp::SHT_RELA);
846       this->emit_relocs_reltype<elfcpp::SHT_RELA>(relinfo, i, prelocs,
847                                                   reloc_count, output_section,
848                                                   offset_in_output_section,
849                                                   view, address, view_size,
850                                                   reloc_view, reloc_view_size);
851     }
852 }
853
854 // Emit the relocs for --emit-relocs, templatized on the type of the
855 // relocation section.
856
857 template<int size, bool big_endian>
858 template<int sh_type>
859 void
860 Sized_relobj<size, big_endian>::emit_relocs_reltype(
861     const Relocate_info<size, big_endian>* relinfo,
862     unsigned int i,
863     const unsigned char* prelocs,
864     size_t reloc_count,
865     Output_section* output_section,
866     typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
867     unsigned char* view,
868     typename elfcpp::Elf_types<size>::Elf_Addr address,
869     section_size_type view_size,
870     unsigned char* reloc_view,
871     section_size_type reloc_view_size)
872 {
873   const Relocatable_relocs* rr = this->relocatable_relocs(i);
874   relocate_for_relocatable<size, big_endian, sh_type>(
875     relinfo,
876     prelocs,
877     reloc_count,
878     output_section,
879     offset_in_output_section,
880     rr,
881     view,
882     address,
883     view_size,
884     reloc_view,
885     reloc_view_size);
886 }
887
888 // Create merge hash tables for the local symbols.  These are used to
889 // speed up relocations.
890
891 template<int size, bool big_endian>
892 void
893 Sized_relobj<size, big_endian>::initialize_input_to_output_maps()
894 {
895   const unsigned int loccount = this->local_symbol_count_;
896   for (unsigned int i = 1; i < loccount; ++i)
897     {
898       Symbol_value<size>& lv(this->local_values_[i]);
899       lv.initialize_input_to_output_map(this);
900     }
901 }
902
903 // Free merge hash tables for the local symbols.
904
905 template<int size, bool big_endian>
906 void
907 Sized_relobj<size, big_endian>::free_input_to_output_maps()
908 {
909   const unsigned int loccount = this->local_symbol_count_;
910   for (unsigned int i = 1; i < loccount; ++i)
911     {
912       Symbol_value<size>& lv(this->local_values_[i]);
913       lv.free_input_to_output_map();
914     }
915 }
916
917 // Class Merged_symbol_value.
918
919 template<int size>
920 void
921 Merged_symbol_value<size>::initialize_input_to_output_map(
922     const Relobj* object,
923     unsigned int input_shndx)
924 {
925   Object_merge_map* map = object->merge_map();
926   map->initialize_input_to_output_map<size>(input_shndx,
927                                             this->output_start_address_,
928                                             &this->output_addresses_);
929 }
930
931 // Get the output value corresponding to an input offset if we
932 // couldn't find it in the hash table.
933
934 template<int size>
935 typename elfcpp::Elf_types<size>::Elf_Addr
936 Merged_symbol_value<size>::value_from_output_section(
937     const Relobj* object,
938     unsigned int input_shndx,
939     typename elfcpp::Elf_types<size>::Elf_Addr input_offset) const
940 {
941   section_offset_type output_offset;
942   bool found = object->merge_map()->get_output_offset(NULL, input_shndx,
943                                                       input_offset,
944                                                       &output_offset);
945
946   // If this assertion fails, it means that some relocation was
947   // against a portion of an input merge section which we didn't map
948   // to the output file and we didn't explicitly discard.  We should
949   // always map all portions of input merge sections.
950   gold_assert(found);
951
952   if (output_offset == -1)
953     return 0;
954   else
955     return this->output_start_address_ + output_offset;
956 }
957
958 // Track_relocs methods.
959
960 // Initialize the class to track the relocs.  This gets the object,
961 // the reloc section index, and the type of the relocs.  This returns
962 // false if something goes wrong.
963
964 template<int size, bool big_endian>
965 bool
966 Track_relocs<size, big_endian>::initialize(
967     Object* object,
968     unsigned int reloc_shndx,
969     unsigned int reloc_type)
970 {
971   // If RELOC_SHNDX is -1U, it means there is more than one reloc
972   // section for the .eh_frame section.  We can't handle that case.
973   if (reloc_shndx == -1U)
974     return false;
975
976   // If RELOC_SHNDX is 0, there is no reloc section.
977   if (reloc_shndx == 0)
978     return true;
979
980   // Get the contents of the reloc section.
981   this->prelocs_ = object->section_contents(reloc_shndx, &this->len_, false);
982
983   if (reloc_type == elfcpp::SHT_REL)
984     this->reloc_size_ = elfcpp::Elf_sizes<size>::rel_size;
985   else if (reloc_type == elfcpp::SHT_RELA)
986     this->reloc_size_ = elfcpp::Elf_sizes<size>::rela_size;
987   else
988     gold_unreachable();
989
990   if (this->len_ % this->reloc_size_ != 0)
991     {
992       object->error(_("reloc section size %zu is not a multiple of "
993                       "reloc size %d\n"),
994                     static_cast<size_t>(this->len_),
995                     this->reloc_size_);
996       return false;
997     }
998
999   return true;
1000 }
1001
1002 // Return the offset of the next reloc, or -1 if there isn't one.
1003
1004 template<int size, bool big_endian>
1005 off_t
1006 Track_relocs<size, big_endian>::next_offset() const
1007 {
1008   if (this->pos_ >= this->len_)
1009     return -1;
1010
1011   // Rel and Rela start out the same, so we can always use Rel to find
1012   // the r_offset value.
1013   elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1014   return rel.get_r_offset();
1015 }
1016
1017 // Return the index of the symbol referenced by the next reloc, or -1U
1018 // if there aren't any more relocs.
1019
1020 template<int size, bool big_endian>
1021 unsigned int
1022 Track_relocs<size, big_endian>::next_symndx() const
1023 {
1024   if (this->pos_ >= this->len_)
1025     return -1U;
1026
1027   // Rel and Rela start out the same, so we can use Rel to find the
1028   // symbol index.
1029   elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1030   return elfcpp::elf_r_sym<size>(rel.get_r_info());
1031 }
1032
1033 // Advance to the next reloc whose r_offset is greater than or equal
1034 // to OFFSET.  Return the number of relocs we skip.
1035
1036 template<int size, bool big_endian>
1037 int
1038 Track_relocs<size, big_endian>::advance(off_t offset)
1039 {
1040   int ret = 0;
1041   while (this->pos_ < this->len_)
1042     {
1043       // Rel and Rela start out the same, so we can always use Rel to
1044       // find the r_offset value.
1045       elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1046       if (static_cast<off_t>(rel.get_r_offset()) >= offset)
1047         break;
1048       ++ret;
1049       this->pos_ += this->reloc_size_;
1050     }
1051   return ret;
1052 }
1053
1054 // Instantiate the templates we need.
1055
1056 #ifdef HAVE_TARGET_32_LITTLE
1057 template
1058 void
1059 Sized_relobj<32, false>::do_read_relocs(Read_relocs_data* rd);
1060 #endif
1061
1062 #ifdef HAVE_TARGET_32_BIG
1063 template
1064 void
1065 Sized_relobj<32, true>::do_read_relocs(Read_relocs_data* rd);
1066 #endif
1067
1068 #ifdef HAVE_TARGET_64_LITTLE
1069 template
1070 void
1071 Sized_relobj<64, false>::do_read_relocs(Read_relocs_data* rd);
1072 #endif
1073
1074 #ifdef HAVE_TARGET_64_BIG
1075 template
1076 void
1077 Sized_relobj<64, true>::do_read_relocs(Read_relocs_data* rd);
1078 #endif
1079
1080 #ifdef HAVE_TARGET_32_LITTLE
1081 template
1082 void
1083 Sized_relobj<32, false>::do_scan_relocs(const General_options& options,
1084                                         Symbol_table* symtab,
1085                                         Layout* layout,
1086                                         Read_relocs_data* rd);
1087 #endif
1088
1089 #ifdef HAVE_TARGET_32_BIG
1090 template
1091 void
1092 Sized_relobj<32, true>::do_scan_relocs(const General_options& options,
1093                                        Symbol_table* symtab,
1094                                        Layout* layout,
1095                                        Read_relocs_data* rd);
1096 #endif
1097
1098 #ifdef HAVE_TARGET_64_LITTLE
1099 template
1100 void
1101 Sized_relobj<64, false>::do_scan_relocs(const General_options& options,
1102                                         Symbol_table* symtab,
1103                                         Layout* layout,
1104                                         Read_relocs_data* rd);
1105 #endif
1106
1107 #ifdef HAVE_TARGET_64_BIG
1108 template
1109 void
1110 Sized_relobj<64, true>::do_scan_relocs(const General_options& options,
1111                                        Symbol_table* symtab,
1112                                        Layout* layout,
1113                                        Read_relocs_data* rd);
1114 #endif
1115
1116 #ifdef HAVE_TARGET_32_LITTLE
1117 template
1118 void
1119 Sized_relobj<32, false>::do_relocate(const General_options& options,
1120                                      const Symbol_table* symtab,
1121                                      const Layout* layout,
1122                                      Output_file* of);
1123 #endif
1124
1125 #ifdef HAVE_TARGET_32_BIG
1126 template
1127 void
1128 Sized_relobj<32, true>::do_relocate(const General_options& options,
1129                                     const Symbol_table* symtab,
1130                                     const Layout* layout,
1131                                     Output_file* of);
1132 #endif
1133
1134 #ifdef HAVE_TARGET_64_LITTLE
1135 template
1136 void
1137 Sized_relobj<64, false>::do_relocate(const General_options& options,
1138                                      const Symbol_table* symtab,
1139                                      const Layout* layout,
1140                                      Output_file* of);
1141 #endif
1142
1143 #ifdef HAVE_TARGET_64_BIG
1144 template
1145 void
1146 Sized_relobj<64, true>::do_relocate(const General_options& options,
1147                                     const Symbol_table* symtab,
1148                                     const Layout* layout,
1149                                     Output_file* of);
1150 #endif
1151
1152 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1153 template
1154 class Merged_symbol_value<32>;
1155 #endif
1156
1157 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1158 template
1159 class Merged_symbol_value<64>;
1160 #endif
1161
1162 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1163 template
1164 class Symbol_value<32>;
1165 #endif
1166
1167 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1168 template
1169 class Symbol_value<64>;
1170 #endif
1171
1172 #ifdef HAVE_TARGET_32_LITTLE
1173 template
1174 class Track_relocs<32, false>;
1175 #endif
1176
1177 #ifdef HAVE_TARGET_32_BIG
1178 template
1179 class Track_relocs<32, true>;
1180 #endif
1181
1182 #ifdef HAVE_TARGET_64_LITTLE
1183 template
1184 class Track_relocs<64, false>;
1185 #endif
1186
1187 #ifdef HAVE_TARGET_64_BIG
1188 template
1189 class Track_relocs<64, true>;
1190 #endif
1191
1192 } // End namespace gold.