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[external/binutils.git] / gold / reloc.cc
1 // reloc.cc -- relocate input files for gold.
2
3 // Copyright (C) 2006-2019 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 "layout.h"
29 #include "symtab.h"
30 #include "output.h"
31 #include "merge.h"
32 #include "object.h"
33 #include "target-reloc.h"
34 #include "reloc.h"
35 #include "icf.h"
36 #include "compressed_output.h"
37 #include "incremental.h"
38
39 namespace gold
40 {
41
42 // Read_relocs methods.
43
44 // These tasks just read the relocation information from the file.
45 // After reading it, the start another task to process the
46 // information.  These tasks requires access to the file.
47
48 Task_token*
49 Read_relocs::is_runnable()
50 {
51   return this->object_->is_locked() ? this->object_->token() : NULL;
52 }
53
54 // Lock the file.
55
56 void
57 Read_relocs::locks(Task_locker* tl)
58 {
59   Task_token* token = this->object_->token();
60   if (token != NULL)
61     tl->add(this, token);
62 }
63
64 // Read the relocations and then start a Scan_relocs_task.
65
66 void
67 Read_relocs::run(Workqueue* workqueue)
68 {
69   Read_relocs_data* rd = new Read_relocs_data;
70   this->object_->read_relocs(rd);
71   this->object_->set_relocs_data(rd);
72   this->object_->release();
73
74   // If garbage collection or identical comdat folding is desired, we  
75   // process the relocs first before scanning them.  Scanning of relocs is
76   // done only after garbage or identical sections is identified.
77   if (parameters->options().gc_sections()
78       || parameters->options().icf_enabled())
79     {
80       workqueue->queue_next(new Gc_process_relocs(this->symtab_,
81                                                   this->layout_, 
82                                                   this->object_, rd,
83                                                   this->this_blocker_,
84                                                   this->next_blocker_));
85     }
86   else
87     {
88       workqueue->queue_next(new Scan_relocs(this->symtab_, this->layout_,
89                                             this->object_, rd,
90                                             this->this_blocker_,
91                                             this->next_blocker_));
92     }
93 }
94
95 // Return a debugging name for the task.
96
97 std::string
98 Read_relocs::get_name() const
99 {
100   return "Read_relocs " + this->object_->name();
101 }
102
103 // Gc_process_relocs methods.
104
105 Gc_process_relocs::~Gc_process_relocs()
106 {
107   if (this->this_blocker_ != NULL)
108     delete this->this_blocker_;
109 }
110
111 // These tasks process the relocations read by Read_relocs and
112 // determine which sections are referenced and which are garbage.
113 // This task is done only when --gc-sections is used.  This is blocked
114 // by THIS_BLOCKER_.  It unblocks NEXT_BLOCKER_.
115
116 Task_token*
117 Gc_process_relocs::is_runnable()
118 {
119   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
120     return this->this_blocker_;
121   if (this->object_->is_locked())
122     return this->object_->token();
123   return NULL;
124 }
125
126 void
127 Gc_process_relocs::locks(Task_locker* tl)
128 {
129   tl->add(this, this->object_->token());
130   tl->add(this, this->next_blocker_);
131 }
132
133 void
134 Gc_process_relocs::run(Workqueue*)
135 {
136   this->object_->gc_process_relocs(this->symtab_, this->layout_, this->rd_);
137   this->object_->release();
138 }
139
140 // Return a debugging name for the task.
141
142 std::string
143 Gc_process_relocs::get_name() const
144 {
145   return "Gc_process_relocs " + this->object_->name();
146 }
147
148 // Scan_relocs methods.
149
150 Scan_relocs::~Scan_relocs()
151 {
152   if (this->this_blocker_ != NULL)
153     delete this->this_blocker_;
154 }
155
156 // These tasks scan the relocations read by Read_relocs and mark up
157 // the symbol table to indicate which relocations are required.  We
158 // use a lock on the symbol table to keep them from interfering with
159 // each other.
160
161 Task_token*
162 Scan_relocs::is_runnable()
163 {
164   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
165     return this->this_blocker_;
166   if (this->object_->is_locked())
167     return this->object_->token();
168   return NULL;
169 }
170
171 // Return the locks we hold: one on the file, one on the symbol table
172 // and one blocker.
173
174 void
175 Scan_relocs::locks(Task_locker* tl)
176 {
177   Task_token* token = this->object_->token();
178   if (token != NULL)
179     tl->add(this, token);
180   tl->add(this, this->next_blocker_);
181 }
182
183 // Scan the relocs.
184
185 void
186 Scan_relocs::run(Workqueue*)
187 {
188   this->object_->scan_relocs(this->symtab_, this->layout_, this->rd_);
189   delete this->rd_;
190   this->rd_ = NULL;
191   this->object_->release();
192 }
193
194 // Return a debugging name for the task.
195
196 std::string
197 Scan_relocs::get_name() const
198 {
199   return "Scan_relocs " + this->object_->name();
200 }
201
202 // Relocate_task methods.
203
204 // We may have to wait for the output sections to be written.
205
206 Task_token*
207 Relocate_task::is_runnable()
208 {
209   if (this->object_->relocs_must_follow_section_writes()
210       && this->output_sections_blocker_->is_blocked())
211     return this->output_sections_blocker_;
212
213   if (this->object_->is_locked())
214     return this->object_->token();
215
216   return NULL;
217 }
218
219 // We want to lock the file while we run.  We want to unblock
220 // INPUT_SECTIONS_BLOCKER and FINAL_BLOCKER when we are done.
221 // INPUT_SECTIONS_BLOCKER may be NULL.
222
223 void
224 Relocate_task::locks(Task_locker* tl)
225 {
226   if (this->input_sections_blocker_ != NULL)
227     tl->add(this, this->input_sections_blocker_);
228   tl->add(this, this->final_blocker_);
229   Task_token* token = this->object_->token();
230   if (token != NULL)
231     tl->add(this, token);
232 }
233
234 // Run the task.
235
236 void
237 Relocate_task::run(Workqueue*)
238 {
239   this->object_->relocate(this->symtab_, this->layout_, this->of_);
240
241   // This is normally the last thing we will do with an object, so
242   // uncache all views.
243   this->object_->clear_view_cache_marks();
244
245   this->object_->release();
246 }
247
248 // Return a debugging name for the task.
249
250 std::string
251 Relocate_task::get_name() const
252 {
253   return "Relocate_task " + this->object_->name();
254 }
255
256 // Read the relocs and local symbols from the object file and store
257 // the information in RD.
258
259 template<int size, bool big_endian>
260 void
261 Sized_relobj_file<size, big_endian>::do_read_relocs(Read_relocs_data* rd)
262 {
263   rd->relocs.clear();
264
265   unsigned int shnum = this->shnum();
266   if (shnum == 0)
267     return;
268
269   rd->relocs.reserve(shnum / 2);
270
271   const Output_sections& out_sections(this->output_sections());
272   const std::vector<Address>& out_offsets(this->section_offsets());
273
274   const unsigned char* pshdrs = this->get_view(this->elf_file_.shoff(),
275                                                shnum * This::shdr_size,
276                                                true, true);
277   // Skip the first, dummy, section.
278   const unsigned char* ps = pshdrs + This::shdr_size;
279   for (unsigned int i = 1; i < shnum; ++i, ps += This::shdr_size)
280     {
281       typename This::Shdr shdr(ps);
282
283       unsigned int sh_type = shdr.get_sh_type();
284       if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
285         continue;
286
287       unsigned int shndx = this->adjust_shndx(shdr.get_sh_info());
288       if (shndx >= shnum)
289         {
290           this->error(_("relocation section %u has bad info %u"),
291                       i, shndx);
292           continue;
293         }
294
295       Output_section* os = out_sections[shndx];
296       if (os == NULL)
297         continue;
298
299       // We are scanning relocations in order to fill out the GOT and
300       // PLT sections.  Relocations for sections which are not
301       // allocated (typically debugging sections) should not add new
302       // GOT and PLT entries.  So we skip them unless this is a
303       // relocatable link or we need to emit relocations.  FIXME: What
304       // should we do if a linker script maps a section with SHF_ALLOC
305       // clear to a section with SHF_ALLOC set?
306       typename This::Shdr secshdr(pshdrs + shndx * This::shdr_size);
307       bool is_section_allocated = ((secshdr.get_sh_flags() & elfcpp::SHF_ALLOC)
308                                    != 0);
309       if (!is_section_allocated
310           && !parameters->options().relocatable()
311           && !parameters->options().emit_relocs()
312           && !parameters->incremental())
313         continue;
314
315       if (this->adjust_shndx(shdr.get_sh_link()) != this->symtab_shndx_)
316         {
317           this->error(_("relocation section %u uses unexpected "
318                         "symbol table %u"),
319                       i, this->adjust_shndx(shdr.get_sh_link()));
320           continue;
321         }
322
323       off_t sh_size = shdr.get_sh_size();
324
325       if (sh_size == 0)
326         continue;
327
328       unsigned int reloc_size;
329       if (sh_type == elfcpp::SHT_REL)
330         reloc_size = elfcpp::Elf_sizes<size>::rel_size;
331       else
332         reloc_size = elfcpp::Elf_sizes<size>::rela_size;
333       if (reloc_size != shdr.get_sh_entsize())
334         {
335           this->error(_("unexpected entsize for reloc section %u: %lu != %u"),
336                       i, static_cast<unsigned long>(shdr.get_sh_entsize()),
337                       reloc_size);
338           continue;
339         }
340
341       size_t reloc_count = sh_size / reloc_size;
342       if (static_cast<off_t>(reloc_count * reloc_size) != sh_size)
343         {
344           this->error(_("reloc section %u size %lu uneven"),
345                       i, static_cast<unsigned long>(sh_size));
346           continue;
347         }
348
349       rd->relocs.push_back(Section_relocs());
350       Section_relocs& sr(rd->relocs.back());
351       sr.reloc_shndx = i;
352       sr.data_shndx = shndx;
353       sr.contents = this->get_lasting_view(shdr.get_sh_offset(), sh_size,
354                                            true, true);
355       sr.sh_type = sh_type;
356       sr.reloc_count = reloc_count;
357       sr.output_section = os;
358       sr.needs_special_offset_handling = out_offsets[shndx] == invalid_address;
359       sr.is_data_section_allocated = is_section_allocated;
360     }
361
362   // Read the local symbols.
363   gold_assert(this->symtab_shndx_ != -1U);
364   if (this->symtab_shndx_ == 0 || this->local_symbol_count_ == 0)
365     rd->local_symbols = NULL;
366   else
367     {
368       typename This::Shdr symtabshdr(pshdrs
369                                      + this->symtab_shndx_ * This::shdr_size);
370       gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
371       const int sym_size = This::sym_size;
372       const unsigned int loccount = this->local_symbol_count_;
373       gold_assert(loccount == symtabshdr.get_sh_info());
374       off_t locsize = loccount * sym_size;
375       rd->local_symbols = this->get_lasting_view(symtabshdr.get_sh_offset(),
376                                                  locsize, true, true);
377     }
378 }
379
380 // Process the relocs to generate mappings from source sections to referenced
381 // sections.  This is used during garbage collection to determine garbage
382 // sections.
383
384 template<int size, bool big_endian>
385 void
386 Sized_relobj_file<size, big_endian>::do_gc_process_relocs(Symbol_table* symtab,
387                                                           Layout* layout,
388                                                           Read_relocs_data* rd)
389 {  
390   Sized_target<size, big_endian>* target =
391     parameters->sized_target<size, big_endian>();
392
393   const unsigned char* local_symbols;
394   if (rd->local_symbols == NULL)
395     local_symbols = NULL;
396   else
397     local_symbols = rd->local_symbols->data();
398
399   for (Read_relocs_data::Relocs_list::iterator p = rd->relocs.begin();
400        p != rd->relocs.end();
401        ++p)
402     {
403       if (!parameters->options().relocatable())
404           {
405             // As noted above, when not generating an object file, we
406             // only scan allocated sections.  We may see a non-allocated
407             // section here if we are emitting relocs.
408             if (p->is_data_section_allocated)
409               target->gc_process_relocs(symtab, layout, this, 
410                                         p->data_shndx, p->sh_type, 
411                                         p->contents->data(), p->reloc_count, 
412                                         p->output_section,
413                                         p->needs_special_offset_handling,
414                                         this->local_symbol_count_, 
415                                         local_symbols);
416         }
417     }
418 }
419
420
421 // Scan the relocs and adjust the symbol table.  This looks for
422 // relocations which require GOT/PLT/COPY relocations.
423
424 template<int size, bool big_endian>
425 void
426 Sized_relobj_file<size, big_endian>::do_scan_relocs(Symbol_table* symtab,
427                                                     Layout* layout,
428                                                     Read_relocs_data* rd)
429 {
430   Sized_target<size, big_endian>* target =
431     parameters->sized_target<size, big_endian>();
432
433   const unsigned char* local_symbols;
434   if (rd->local_symbols == NULL)
435     local_symbols = NULL;
436   else
437     local_symbols = rd->local_symbols->data();
438
439   // For incremental links, allocate the counters for incremental relocations.
440   if (layout->incremental_inputs() != NULL)
441     this->allocate_incremental_reloc_counts();
442
443   for (Read_relocs_data::Relocs_list::iterator p = rd->relocs.begin();
444        p != rd->relocs.end();
445        ++p)
446     {
447       // When garbage collection is on, unreferenced sections are not included
448       // in the link that would have been included normally. This is known only
449       // after Read_relocs hence this check has to be done again.
450       if (parameters->options().gc_sections()
451           || parameters->options().icf_enabled())
452         {
453           if (p->output_section == NULL)
454             continue;
455         }
456       if (!parameters->options().relocatable())
457         {
458           // As noted above, when not generating an object file, we
459           // only scan allocated sections.  We may see a non-allocated
460           // section here if we are emitting relocs.
461           if (p->is_data_section_allocated)
462             target->scan_relocs(symtab, layout, this, p->data_shndx,
463                                 p->sh_type, p->contents->data(),
464                                 p->reloc_count, p->output_section,
465                                 p->needs_special_offset_handling,
466                                 this->local_symbol_count_,
467                                 local_symbols);
468           if (parameters->options().emit_relocs())
469             this->emit_relocs_scan(symtab, layout, local_symbols, p);
470           if (layout->incremental_inputs() != NULL)
471             this->incremental_relocs_scan(p);
472         }
473       else
474         {
475           Relocatable_relocs* rr = this->relocatable_relocs(p->reloc_shndx);
476           gold_assert(rr != NULL);
477           rr->set_reloc_count(p->reloc_count);
478           target->scan_relocatable_relocs(symtab, layout, this,
479                                           p->data_shndx, p->sh_type,
480                                           p->contents->data(),
481                                           p->reloc_count,
482                                           p->output_section,
483                                           p->needs_special_offset_handling,
484                                           this->local_symbol_count_,
485                                           local_symbols,
486                                           rr);
487         }
488
489       delete p->contents;
490       p->contents = NULL;
491     }
492
493   // For incremental links, finalize the allocation of relocations.
494   if (layout->incremental_inputs() != NULL)
495     this->finalize_incremental_relocs(layout, true);
496
497   if (rd->local_symbols != NULL)
498     {
499       delete rd->local_symbols;
500       rd->local_symbols = NULL;
501     }
502 }
503
504 // Scan the input relocations for --emit-relocs.
505
506 template<int size, bool big_endian>
507 void
508 Sized_relobj_file<size, big_endian>::emit_relocs_scan(
509     Symbol_table* symtab,
510     Layout* layout,
511     const unsigned char* plocal_syms,
512     const Read_relocs_data::Relocs_list::iterator& p)
513 {
514   Sized_target<size, big_endian>* target =
515       parameters->sized_target<size, big_endian>();
516
517   Relocatable_relocs* rr = this->relocatable_relocs(p->reloc_shndx);
518   gold_assert(rr != NULL);
519   rr->set_reloc_count(p->reloc_count);
520   target->emit_relocs_scan(
521     symtab,
522     layout,
523     this,
524     p->data_shndx,
525     p->sh_type,
526     p->contents->data(),
527     p->reloc_count,
528     p->output_section,
529     p->needs_special_offset_handling,
530     this->local_symbol_count_,
531     plocal_syms,
532     rr);
533 }
534
535 // Scan the input relocations for --incremental.
536
537 template<int size, bool big_endian>
538 void
539 Sized_relobj_file<size, big_endian>::incremental_relocs_scan(
540     const Read_relocs_data::Relocs_list::iterator& p)
541 {
542   if (p->sh_type == elfcpp::SHT_REL)
543     this->incremental_relocs_scan_reltype<elfcpp::SHT_REL>(p);
544   else
545     {
546       gold_assert(p->sh_type == elfcpp::SHT_RELA);
547       this->incremental_relocs_scan_reltype<elfcpp::SHT_RELA>(p);
548     }
549 }
550
551 // Scan the input relocation for --incremental, templatized on the
552 // type of the relocation section.
553
554 template<int size, bool big_endian>
555 template<int sh_type>
556 void
557 Sized_relobj_file<size, big_endian>::incremental_relocs_scan_reltype(
558     const Read_relocs_data::Relocs_list::iterator& p)
559 {
560   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
561   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
562   const unsigned char* prelocs = p->contents->data();
563   size_t reloc_count = p->reloc_count;
564
565   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
566     {
567       Reltype reloc(prelocs);
568
569       if (p->needs_special_offset_handling
570           && !p->output_section->is_input_address_mapped(this, p->data_shndx,
571                                                          reloc.get_r_offset()))
572         continue;
573
574       // FIXME: Some targets have a non-standard r_info field.
575       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
576       const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
577
578       if (r_sym >= this->local_symbol_count_)
579         this->count_incremental_reloc(r_sym - this->local_symbol_count_);
580     }
581 }
582
583 // Relocate the input sections and write out the local symbols.
584
585 template<int size, bool big_endian>
586 void
587 Sized_relobj_file<size, big_endian>::do_relocate(const Symbol_table* symtab,
588                                                  const Layout* layout,
589                                                  Output_file* of)
590 {
591   unsigned int shnum = this->shnum();
592
593   // Read the section headers.
594   const unsigned char* pshdrs = this->get_view(this->elf_file_.shoff(),
595                                                shnum * This::shdr_size,
596                                                true, true);
597
598   Views views;
599   views.resize(shnum);
600
601   // Make two passes over the sections.  The first one copies the
602   // section data to the output file.  The second one applies
603   // relocations.
604
605   this->write_sections(layout, pshdrs, of, &views);
606
607   // To speed up relocations, we set up hash tables for fast lookup of
608   // input offsets to output addresses.
609   this->initialize_input_to_output_maps();
610
611   // Make the views available through get_output_view() for the duration
612   // of this routine.  This RAII class will reset output_views_ to NULL
613   // when the views go out of scope.
614   struct Set_output_views
615   {
616     Set_output_views(const Views** ppviews, const Views* pviews)
617     {
618       ppviews_ = ppviews;
619       *ppviews = pviews;
620     }
621
622     ~Set_output_views()
623     { *ppviews_ = NULL; }
624
625     const Views** ppviews_;
626   };
627   Set_output_views set_output_views(&this->output_views_, &views);
628
629   // Apply relocations.
630
631   this->relocate_sections(symtab, layout, pshdrs, of, &views);
632
633   // After we've done the relocations, we release the hash tables,
634   // since we no longer need them.
635   this->free_input_to_output_maps();
636
637   // Write out the accumulated views.
638   for (unsigned int i = 1; i < shnum; ++i)
639     {
640       if (views[i].view != NULL)
641         {
642           if (views[i].is_ctors_reverse_view)
643             this->reverse_words(views[i].view, views[i].view_size);
644           if (!views[i].is_postprocessing_view)
645             {
646               if (views[i].is_input_output_view)
647                 of->write_input_output_view(views[i].offset,
648                                             views[i].view_size,
649                                             views[i].view);
650               else
651                 of->write_output_view(views[i].offset, views[i].view_size,
652                                       views[i].view);
653             }
654         }
655     }
656
657   // Write out the local symbols.
658   this->write_local_symbols(of, layout->sympool(), layout->dynpool(),
659                             layout->symtab_xindex(), layout->dynsym_xindex(),
660                             layout->symtab_section_offset());
661 }
662
663 // Sort a Read_multiple vector by file offset.
664 struct Read_multiple_compare
665 {
666   inline bool
667   operator()(const File_read::Read_multiple_entry& rme1,
668              const File_read::Read_multiple_entry& rme2) const
669   { return rme1.file_offset < rme2.file_offset; }
670 };
671
672 // Write section data to the output file.  PSHDRS points to the
673 // section headers.  Record the views in *PVIEWS for use when
674 // relocating.
675
676 template<int size, bool big_endian>
677 void
678 Sized_relobj_file<size, big_endian>::write_sections(const Layout* layout,
679                                                     const unsigned char* pshdrs,
680                                                     Output_file* of,
681                                                     Views* pviews)
682 {
683   unsigned int shnum = this->shnum();
684   const Output_sections& out_sections(this->output_sections());
685   const std::vector<Address>& out_offsets(this->section_offsets());
686
687   File_read::Read_multiple rm;
688   bool is_sorted = true;
689
690   const unsigned char* p = pshdrs + This::shdr_size;
691   for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
692     {
693       View_size* pvs = &(*pviews)[i];
694
695       pvs->view = NULL;
696
697       const Output_section* os = out_sections[i];
698       if (os == NULL)
699         continue;
700       Address output_offset = out_offsets[i];
701
702       typename This::Shdr shdr(p);
703
704       if (shdr.get_sh_type() == elfcpp::SHT_NOBITS)
705         continue;
706
707       if ((parameters->options().relocatable()
708            || parameters->options().emit_relocs())
709           && (shdr.get_sh_type() == elfcpp::SHT_REL
710               || shdr.get_sh_type() == elfcpp::SHT_RELA)
711           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
712         {
713           // This is a reloc section in a relocatable link or when
714           // emitting relocs.  We don't need to read the input file.
715           // The size and file offset are stored in the
716           // Relocatable_relocs structure.
717           Relocatable_relocs* rr = this->relocatable_relocs(i);
718           gold_assert(rr != NULL);
719           Output_data* posd = rr->output_data();
720           gold_assert(posd != NULL);
721
722           pvs->offset = posd->offset();
723           pvs->view_size = posd->data_size();
724           pvs->view = of->get_output_view(pvs->offset, pvs->view_size);
725           pvs->address = posd->address();
726           pvs->is_input_output_view = false;
727           pvs->is_postprocessing_view = false;
728           pvs->is_ctors_reverse_view = false;
729
730           continue;
731         }
732
733       // In the normal case, this input section is simply mapped to
734       // the output section at offset OUTPUT_OFFSET.
735
736       // However, if OUTPUT_OFFSET == INVALID_ADDRESS, then input data is
737       // handled specially--e.g., a .eh_frame section.  The relocation
738       // routines need to check for each reloc where it should be
739       // applied.  For this case, we need an input/output view for the
740       // entire contents of the section in the output file.  We don't
741       // want to copy the contents of the input section to the output
742       // section; the output section contents were already written,
743       // and we waited for them in Relocate_task::is_runnable because
744       // relocs_must_follow_section_writes is set for the object.
745
746       // Regardless of which of the above cases is true, we have to
747       // check requires_postprocessing of the output section.  If that
748       // is false, then we work with views of the output file
749       // directly.  If it is true, then we work with a separate
750       // buffer, and the output section is responsible for writing the
751       // final data to the output file.
752
753       off_t output_section_offset;
754       Address output_section_size;
755       if (!os->requires_postprocessing())
756         {
757           output_section_offset = os->offset();
758           output_section_size = convert_types<Address, off_t>(os->data_size());
759         }
760       else
761         {
762           output_section_offset = 0;
763           output_section_size =
764               convert_types<Address, off_t>(os->postprocessing_buffer_size());
765         }
766
767       off_t view_start;
768       section_size_type view_size;
769       bool must_decompress = false;
770       if (output_offset != invalid_address)
771         {
772           view_start = output_section_offset + output_offset;
773           view_size = convert_to_section_size_type(shdr.get_sh_size());
774           section_size_type uncompressed_size;
775           if (this->section_is_compressed(i, &uncompressed_size))
776             {
777               view_size = uncompressed_size;
778               must_decompress = true;
779             }
780         }
781       else
782         {
783           view_start = output_section_offset;
784           view_size = convert_to_section_size_type(output_section_size);
785         }
786
787       if (view_size == 0)
788         continue;
789
790       gold_assert(output_offset == invalid_address
791                   || output_offset + view_size <= output_section_size);
792
793       unsigned char* view;
794       if (os->requires_postprocessing())
795         {
796           unsigned char* buffer = os->postprocessing_buffer();
797           view = buffer + view_start;
798           if (output_offset != invalid_address && !must_decompress)
799             {
800               off_t sh_offset = shdr.get_sh_offset();
801               if (!rm.empty() && rm.back().file_offset > sh_offset)
802                 is_sorted = false;
803               rm.push_back(File_read::Read_multiple_entry(sh_offset,
804                                                           view_size, view));
805             }
806         }
807       else
808         {
809           if (output_offset == invalid_address)
810             view = of->get_input_output_view(view_start, view_size);
811           else
812             {
813               view = of->get_output_view(view_start, view_size);
814               if (!must_decompress)
815                 {
816                   off_t sh_offset = shdr.get_sh_offset();
817                   if (!rm.empty() && rm.back().file_offset > sh_offset)
818                     is_sorted = false;
819                   rm.push_back(File_read::Read_multiple_entry(sh_offset,
820                                                               view_size, view));
821                 }
822             }
823         }
824
825       if (must_decompress)
826         {
827           // Read and decompress the section.
828           section_size_type len;
829           const unsigned char* p = this->section_contents(i, &len, false);
830           if (!decompress_input_section(p, len, view, view_size,
831                                         size, big_endian,
832                                         shdr.get_sh_flags()))
833             this->error(_("could not decompress section %s"),
834                         this->section_name(i).c_str());
835         }
836
837       pvs->view = view;
838       pvs->address = os->address();
839       if (output_offset != invalid_address)
840         pvs->address += output_offset;
841       pvs->offset = view_start;
842       pvs->view_size = view_size;
843       pvs->is_input_output_view = output_offset == invalid_address;
844       pvs->is_postprocessing_view = os->requires_postprocessing();
845       pvs->is_ctors_reverse_view =
846         (!parameters->options().relocatable()
847          && view_size > size / 8
848          && (strcmp(os->name(), ".init_array") == 0
849              || strcmp(os->name(), ".fini_array") == 0)
850          && layout->is_ctors_in_init_array(this, i));
851     }
852
853   // Actually read the data.
854   if (!rm.empty())
855     {
856       if (!is_sorted)
857         std::sort(rm.begin(), rm.end(), Read_multiple_compare());
858       this->read_multiple(rm);
859     }
860 }
861
862 // Relocate section data.  VIEWS points to the section data as views
863 // in the output file.
864
865 template<int size, bool big_endian>
866 void
867 Sized_relobj_file<size, big_endian>::do_relocate_sections(
868     const Symbol_table* symtab,
869     const Layout* layout,
870     const unsigned char* pshdrs,
871     Output_file* of,
872     Views* pviews)
873 {
874   this->relocate_section_range(symtab, layout, pshdrs, of, pviews,
875                                1, this->shnum() - 1);
876 }
877
878 // Relocate section data for the range of sections START_SHNDX through
879 // END_SHNDX.
880
881 template<int size, bool big_endian>
882 void
883 Sized_relobj_file<size, big_endian>::relocate_section_range(
884     const Symbol_table* symtab,
885     const Layout* layout,
886     const unsigned char* pshdrs,
887     Output_file* of,
888     Views* pviews,
889     unsigned int start_shndx,
890     unsigned int end_shndx)
891 {
892   gold_assert(start_shndx >= 1);
893   gold_assert(end_shndx < this->shnum());
894
895   if (end_shndx < start_shndx)
896     return;
897
898   Sized_target<size, big_endian>* target =
899     parameters->sized_target<size, big_endian>();
900
901   const Output_sections& out_sections(this->output_sections());
902   const std::vector<Address>& out_offsets(this->section_offsets());
903
904   Relocate_info<size, big_endian> relinfo;
905   relinfo.symtab = symtab;
906   relinfo.layout = layout;
907   relinfo.object = this;
908
909   const unsigned char* p = pshdrs + start_shndx * This::shdr_size;
910   for (unsigned int i = start_shndx; i <= end_shndx; ++i, p += This::shdr_size)
911     {
912       typename This::Shdr shdr(p);
913
914       unsigned int sh_type = shdr.get_sh_type();
915       if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
916         continue;
917
918       off_t sh_size = shdr.get_sh_size();
919       if (sh_size == 0)
920         continue;
921
922       unsigned int index = this->adjust_shndx(shdr.get_sh_info());
923       if (index >= this->shnum())
924         {
925           this->error(_("relocation section %u has bad info %u"),
926                       i, index);
927           continue;
928         }
929
930       Output_section* os = out_sections[index];
931       if (os == NULL)
932         {
933           // This relocation section is against a section which we
934           // discarded.
935           continue;
936         }
937       Address output_offset = out_offsets[index];
938
939       gold_assert((*pviews)[index].view != NULL);
940       if (parameters->options().relocatable())
941         gold_assert((*pviews)[i].view != NULL);
942
943       if (this->adjust_shndx(shdr.get_sh_link()) != this->symtab_shndx_)
944         {
945           gold_error(_("relocation section %u uses unexpected "
946                        "symbol table %u"),
947                      i, this->adjust_shndx(shdr.get_sh_link()));
948           continue;
949         }
950
951       const unsigned char* prelocs = this->get_view(shdr.get_sh_offset(),
952                                                     sh_size, true, false);
953
954       unsigned int reloc_size;
955       if (sh_type == elfcpp::SHT_REL)
956         reloc_size = elfcpp::Elf_sizes<size>::rel_size;
957       else
958         reloc_size = elfcpp::Elf_sizes<size>::rela_size;
959
960       if (reloc_size != shdr.get_sh_entsize())
961         {
962           gold_error(_("unexpected entsize for reloc section %u: %lu != %u"),
963                      i, static_cast<unsigned long>(shdr.get_sh_entsize()),
964                      reloc_size);
965           continue;
966         }
967
968       size_t reloc_count = sh_size / reloc_size;
969       if (static_cast<off_t>(reloc_count * reloc_size) != sh_size)
970         {
971           gold_error(_("reloc section %u size %lu uneven"),
972                      i, static_cast<unsigned long>(sh_size));
973           continue;
974         }
975
976       gold_assert(output_offset != invalid_address
977                   || this->relocs_must_follow_section_writes());
978
979       relinfo.reloc_shndx = i;
980       relinfo.reloc_shdr = p;
981       relinfo.data_shndx = index;
982       relinfo.data_shdr = pshdrs + index * This::shdr_size;
983       unsigned char* view = (*pviews)[index].view;
984       Address address = (*pviews)[index].address;
985       section_size_type view_size = (*pviews)[index].view_size;
986
987       Reloc_symbol_changes* reloc_map = NULL;
988       if (this->uses_split_stack() && output_offset != invalid_address)
989         {
990           typename This::Shdr data_shdr(pshdrs + index * This::shdr_size);
991           if ((data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
992             this->split_stack_adjust(symtab, pshdrs, sh_type, index,
993                                      prelocs, reloc_count, view, view_size,
994                                      &reloc_map, target);
995         }
996
997       Relocatable_relocs* rr = NULL;
998       if (parameters->options().emit_relocs()
999           || parameters->options().relocatable())
1000         rr = this->relocatable_relocs(i);
1001       relinfo.rr = rr;
1002
1003       if (!parameters->options().relocatable())
1004         {
1005           target->relocate_section(&relinfo, sh_type, prelocs, reloc_count, os,
1006                                    output_offset == invalid_address,
1007                                    view, address, view_size, reloc_map);
1008           if (parameters->options().emit_relocs())
1009             target->relocate_relocs(&relinfo, sh_type, prelocs, reloc_count,
1010                                     os, output_offset,
1011                                     view, address, view_size,
1012                                     (*pviews)[i].view,
1013                                     (*pviews)[i].view_size);
1014           if (parameters->incremental())
1015             this->incremental_relocs_write(&relinfo, sh_type, prelocs,
1016                                            reloc_count, os, output_offset, of);
1017         }
1018       else
1019         target->relocate_relocs(&relinfo, sh_type, prelocs, reloc_count,
1020                                 os, output_offset,
1021                                 view, address, view_size,
1022                                 (*pviews)[i].view,
1023                                 (*pviews)[i].view_size);
1024     }
1025 }
1026
1027 // Return the output view for section SHNDX.
1028
1029 template<int size, bool big_endian>
1030 unsigned char*
1031 Sized_relobj_file<size, big_endian>::do_get_output_view(
1032     unsigned int shndx,
1033     section_size_type* plen) const
1034 {
1035   gold_assert(this->output_views_ != NULL);
1036   gold_assert(shndx < this->output_views_->size());
1037   const View_size& v = (*this->output_views_)[shndx];
1038   *plen = v.view_size;
1039   return v.view;
1040 }
1041
1042 // Write the incremental relocs.
1043
1044 template<int size, bool big_endian>
1045 void
1046 Sized_relobj_file<size, big_endian>::incremental_relocs_write(
1047     const Relocate_info<size, big_endian>* relinfo,
1048     unsigned int sh_type,
1049     const unsigned char* prelocs,
1050     size_t reloc_count,
1051     Output_section* output_section,
1052     Address output_offset,
1053     Output_file* of)
1054 {
1055   if (sh_type == elfcpp::SHT_REL)
1056     this->incremental_relocs_write_reltype<elfcpp::SHT_REL>(
1057         relinfo,
1058         prelocs,
1059         reloc_count,
1060         output_section,
1061         output_offset,
1062         of);
1063   else
1064     {
1065       gold_assert(sh_type == elfcpp::SHT_RELA);
1066       this->incremental_relocs_write_reltype<elfcpp::SHT_RELA>(
1067           relinfo,
1068           prelocs,
1069           reloc_count,
1070           output_section,
1071           output_offset,
1072           of);
1073     }
1074 }
1075
1076 // Write the incremental relocs, templatized on the type of the
1077 // relocation section.
1078
1079 template<int size, bool big_endian>
1080 template<int sh_type>
1081 void
1082 Sized_relobj_file<size, big_endian>::incremental_relocs_write_reltype(
1083     const Relocate_info<size, big_endian>* relinfo,
1084     const unsigned char* prelocs,
1085     size_t reloc_count,
1086     Output_section* output_section,
1087     Address output_offset,
1088     Output_file* of)
1089 {
1090   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reloc;
1091   const unsigned int reloc_size =
1092       Reloc_types<sh_type, size, big_endian>::reloc_size;
1093   const unsigned int sizeof_addr = size / 8;
1094   const unsigned int incr_reloc_size =
1095       Incremental_relocs_reader<size, big_endian>::reloc_size;
1096
1097   unsigned int out_shndx = output_section->out_shndx();
1098
1099   // Get a view for the .gnu_incremental_relocs section.
1100
1101   Incremental_inputs* inputs = relinfo->layout->incremental_inputs();
1102   gold_assert(inputs != NULL);
1103   const off_t relocs_off = inputs->relocs_section()->offset();
1104   const off_t relocs_size = inputs->relocs_section()->data_size();
1105   unsigned char* const view = of->get_output_view(relocs_off, relocs_size);
1106
1107   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
1108     {
1109       Reloc reloc(prelocs);
1110
1111       // FIXME: Some targets have a non-standard r_info field.
1112       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
1113       const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
1114       const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
1115
1116       if (r_sym < this->local_symbol_count_)
1117         continue;
1118
1119       // Get the new offset--the location in the output section where
1120       // this relocation should be applied.
1121
1122       Address offset = reloc.get_r_offset();
1123       if (output_offset != invalid_address)
1124         offset += output_offset;
1125       else
1126         {
1127           section_offset_type sot_offset =
1128               convert_types<section_offset_type, Address>(offset);
1129           section_offset_type new_sot_offset =
1130               output_section->output_offset(relinfo->object,
1131                                             relinfo->data_shndx,
1132                                             sot_offset);
1133           gold_assert(new_sot_offset != -1);
1134           offset += new_sot_offset;
1135         }
1136
1137       // Get the addend.
1138       typename elfcpp::Elf_types<size>::Elf_Swxword addend;
1139       if (sh_type == elfcpp::SHT_RELA)
1140         addend =
1141             Reloc_types<sh_type, size, big_endian>::get_reloc_addend(&reloc);
1142       else
1143         {
1144           // FIXME: Get the addend for SHT_REL.
1145           addend = 0;
1146         }
1147
1148       // Get the index of the output relocation.
1149
1150       unsigned int reloc_index =
1151           this->next_incremental_reloc_index(r_sym - this->local_symbol_count_);
1152
1153       // Write the relocation.
1154
1155       unsigned char* pov = view + reloc_index * incr_reloc_size;
1156       elfcpp::Swap<32, big_endian>::writeval(pov, r_type);
1157       elfcpp::Swap<32, big_endian>::writeval(pov + 4, out_shndx);
1158       elfcpp::Swap<size, big_endian>::writeval(pov + 8, offset);
1159       elfcpp::Swap<size, big_endian>::writeval(pov + 8 + sizeof_addr, addend);
1160       of->write_output_view(pov - view, incr_reloc_size, view);
1161     }
1162 }
1163
1164 // Create merge hash tables for the local symbols.  These are used to
1165 // speed up relocations.
1166
1167 template<int size, bool big_endian>
1168 void
1169 Sized_relobj_file<size, big_endian>::initialize_input_to_output_maps()
1170 {
1171   const unsigned int loccount = this->local_symbol_count_;
1172   for (unsigned int i = 1; i < loccount; ++i)
1173     {
1174       Symbol_value<size>& lv(this->local_values_[i]);
1175       lv.initialize_input_to_output_map(this);
1176     }
1177 }
1178
1179 // Free merge hash tables for the local symbols.
1180
1181 template<int size, bool big_endian>
1182 void
1183 Sized_relobj_file<size, big_endian>::free_input_to_output_maps()
1184 {
1185   const unsigned int loccount = this->local_symbol_count_;
1186   for (unsigned int i = 1; i < loccount; ++i)
1187     {
1188       Symbol_value<size>& lv(this->local_values_[i]);
1189       lv.free_input_to_output_map();
1190     }
1191 }
1192
1193 // If an object was compiled with -fsplit-stack, this is called to
1194 // check whether any relocations refer to functions defined in objects
1195 // which were not compiled with -fsplit-stack.  If they were, then we
1196 // need to apply some target-specific adjustments to request
1197 // additional stack space.
1198
1199 template<int size, bool big_endian>
1200 void
1201 Sized_relobj_file<size, big_endian>::split_stack_adjust(
1202     const Symbol_table* symtab,
1203     const unsigned char* pshdrs,
1204     unsigned int sh_type,
1205     unsigned int shndx,
1206     const unsigned char* prelocs,
1207     size_t reloc_count,
1208     unsigned char* view,
1209     section_size_type view_size,
1210     Reloc_symbol_changes** reloc_map,
1211     const Sized_target<size, big_endian>* target)
1212 {
1213   if (sh_type == elfcpp::SHT_REL)
1214     this->split_stack_adjust_reltype<elfcpp::SHT_REL>(symtab, pshdrs, shndx,
1215                                                       prelocs, reloc_count,
1216                                                       view, view_size,
1217                                                       reloc_map, target);
1218   else
1219     {
1220       gold_assert(sh_type == elfcpp::SHT_RELA);
1221       this->split_stack_adjust_reltype<elfcpp::SHT_RELA>(symtab, pshdrs, shndx,
1222                                                          prelocs, reloc_count,
1223                                                          view, view_size,
1224                                                          reloc_map, target);
1225     }
1226 }
1227
1228 // Adjust for -fsplit-stack, templatized on the type of the relocation
1229 // section.
1230
1231 template<int size, bool big_endian>
1232 template<int sh_type>
1233 void
1234 Sized_relobj_file<size, big_endian>::split_stack_adjust_reltype(
1235     const Symbol_table* symtab,
1236     const unsigned char* pshdrs,
1237     unsigned int shndx,
1238     const unsigned char* prelocs,
1239     size_t reloc_count,
1240     unsigned char* view,
1241     section_size_type view_size,
1242     Reloc_symbol_changes** reloc_map,
1243     const Sized_target<size, big_endian>* target)
1244 {
1245   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
1246   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
1247
1248   size_t local_count = this->local_symbol_count();
1249
1250   std::vector<section_offset_type> non_split_refs;
1251
1252   const unsigned char* pr = prelocs;
1253   for (size_t i = 0; i < reloc_count; ++i, pr += reloc_size)
1254     {
1255       // Some supported targets have a non-standard r_info field.
1256       // If this call is too slow, we can move this routine to
1257       // target-reloc.h and templatize it on Classify_reloc.
1258       unsigned int r_sym = target->get_r_sym(pr);
1259       if (r_sym < local_count)
1260         continue;
1261
1262       const Symbol* gsym = this->global_symbol(r_sym);
1263       gold_assert(gsym != NULL);
1264       if (gsym->is_forwarder())
1265         gsym = symtab->resolve_forwards(gsym);
1266
1267       // See if this relocation refers to a function defined in an
1268       // object compiled without -fsplit-stack.  Note that we don't
1269       // care about the type of relocation--this means that in some
1270       // cases we will ask for a large stack unnecessarily, but this
1271       // is not fatal.  FIXME: Some targets have symbols which are
1272       // functions but are not type STT_FUNC, e.g., STT_ARM_TFUNC.
1273       if (!gsym->is_undefined()
1274           && gsym->source() == Symbol::FROM_OBJECT
1275           && !gsym->object()->uses_split_stack())
1276         {
1277           if (parameters->target().is_call_to_non_split(gsym, pr, view,
1278                                                         view_size))
1279             {
1280               Reltype reloc(pr);
1281               section_offset_type offset =
1282                 convert_to_section_size_type(reloc.get_r_offset());
1283               non_split_refs.push_back(offset);
1284             }
1285         }
1286     }
1287
1288   if (non_split_refs.empty())
1289     return;
1290
1291   // At this point, every entry in NON_SPLIT_REFS indicates a
1292   // relocation which refers to a function in an object compiled
1293   // without -fsplit-stack.  We now have to convert that list into a
1294   // set of offsets to functions.  First, we find all the functions.
1295
1296   Function_offsets function_offsets;
1297   this->find_functions(pshdrs, shndx, &function_offsets);
1298   if (function_offsets.empty())
1299     return;
1300
1301   // Now get a list of the function with references to non split-stack
1302   // code.
1303
1304   Function_offsets calls_non_split;
1305   for (std::vector<section_offset_type>::const_iterator p
1306          = non_split_refs.begin();
1307        p != non_split_refs.end();
1308        ++p)
1309     {
1310       Function_offsets::const_iterator low = function_offsets.lower_bound(*p);
1311       if (low == function_offsets.end())
1312         --low;
1313       else if (low->first == *p)
1314         ;
1315       else if (low == function_offsets.begin())
1316         continue;
1317       else
1318         --low;
1319
1320       calls_non_split.insert(*low);
1321     }
1322   if (calls_non_split.empty())
1323     return;
1324
1325   // Now we have a set of functions to adjust.  The adjustments are
1326   // target specific.  Besides changing the output section view
1327   // however, it likes, the target may request a relocation change
1328   // from one global symbol name to another.
1329
1330   for (Function_offsets::const_iterator p = calls_non_split.begin();
1331        p != calls_non_split.end();
1332        ++p)
1333     {
1334       std::string from;
1335       std::string to;
1336       parameters->target().calls_non_split(this, shndx, p->first, p->second,
1337                                            prelocs, reloc_count,
1338                                            view, view_size, &from, &to);
1339       if (!from.empty())
1340         {
1341           gold_assert(!to.empty());
1342           Symbol* tosym = NULL;
1343
1344           // Find relocations in the relevant function which are for
1345           // FROM.
1346           pr = prelocs;
1347           for (size_t i = 0; i < reloc_count; ++i, pr += reloc_size)
1348             {
1349               Reltype reloc(pr);
1350
1351               unsigned int r_sym = target->get_r_sym(pr);
1352               if (r_sym < local_count)
1353                 continue;
1354
1355               section_offset_type offset =
1356                 convert_to_section_size_type(reloc.get_r_offset());
1357               if (offset < p->first
1358                   || (offset
1359                       >= (p->first
1360                           + static_cast<section_offset_type>(p->second))))
1361                 continue;
1362
1363               const Symbol* gsym = this->global_symbol(r_sym);
1364               if (from == gsym->name())
1365                 {
1366                   if (tosym == NULL)
1367                     {
1368                       tosym = symtab->lookup(to.c_str());
1369                       if (tosym == NULL)
1370                         {
1371                           this->error(_("could not convert call "
1372                                         "to '%s' to '%s'"),
1373                                       from.c_str(), to.c_str());
1374                           break;
1375                         }
1376                     }
1377
1378                   if (*reloc_map == NULL)
1379                     *reloc_map = new Reloc_symbol_changes(reloc_count);
1380                   (*reloc_map)->set(i, tosym);
1381                 }
1382             }
1383         }
1384     }
1385 }
1386
1387 // Find all the function in this object defined in section SHNDX.
1388 // Store their offsets in the section in FUNCTION_OFFSETS.
1389
1390 template<int size, bool big_endian>
1391 void
1392 Sized_relobj_file<size, big_endian>::find_functions(
1393     const unsigned char* pshdrs,
1394     unsigned int shndx,
1395     Sized_relobj_file<size, big_endian>::Function_offsets* function_offsets)
1396 {
1397   // We need to read the symbols to find the functions.  If we wanted
1398   // to, we could cache reading the symbols across all sections in the
1399   // object.
1400   const unsigned int symtab_shndx = this->symtab_shndx_;
1401   typename This::Shdr symtabshdr(pshdrs + symtab_shndx * This::shdr_size);
1402   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
1403
1404   typename elfcpp::Elf_types<size>::Elf_WXword sh_size =
1405     symtabshdr.get_sh_size();
1406   const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
1407                                               sh_size, true, true);
1408
1409   const int sym_size = This::sym_size;
1410   const unsigned int symcount = sh_size / sym_size;
1411   for (unsigned int i = 0; i < symcount; ++i, psyms += sym_size)
1412     {
1413       typename elfcpp::Sym<size, big_endian> isym(psyms);
1414
1415       // FIXME: Some targets can have functions which do not have type
1416       // STT_FUNC, e.g., STT_ARM_TFUNC.
1417       if (isym.get_st_type() != elfcpp::STT_FUNC
1418           || isym.get_st_size() == 0)
1419         continue;
1420
1421       bool is_ordinary;
1422       Symbol_location loc;
1423       loc.shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
1424                                          &is_ordinary);
1425       if (!is_ordinary)
1426         continue;
1427
1428       loc.object = this;
1429       loc.offset = isym.get_st_value();
1430       parameters->target().function_location(&loc);
1431
1432       if (loc.shndx != shndx)
1433         continue;
1434
1435       section_offset_type value =
1436         convert_to_section_size_type(loc.offset);
1437       section_size_type fnsize =
1438         convert_to_section_size_type(isym.get_st_size());
1439
1440       (*function_offsets)[value] = fnsize;
1441     }
1442 }
1443
1444 // Reverse the words in a section.  Used for .ctors sections mapped to
1445 // .init_array sections.  See ctors_sections_in_init_array in
1446 // layout.cc.
1447
1448 template<int size, bool big_endian>
1449 void
1450 Sized_relobj_file<size, big_endian>::reverse_words(unsigned char* view,
1451                                                    section_size_type view_size)
1452 {
1453   typedef typename elfcpp::Swap<size, big_endian>::Valtype Valtype;
1454   Valtype* vview = reinterpret_cast<Valtype*>(view);
1455   section_size_type vview_size = view_size / (size / 8);
1456   for (section_size_type i = 0; i < vview_size / 2; ++i)
1457     {
1458       Valtype tmp = vview[i];
1459       vview[i] = vview[vview_size - 1 - i];
1460       vview[vview_size - 1 - i] = tmp;
1461     }
1462 }
1463
1464 // Class Merged_symbol_value.
1465
1466 template<int size>
1467 void
1468 Merged_symbol_value<size>::initialize_input_to_output_map(
1469     const Relobj* object,
1470     unsigned int input_shndx)
1471 {
1472   object->initialize_input_to_output_map<size>(input_shndx,
1473                                                this->output_start_address_,
1474                                                &this->output_addresses_);
1475 }
1476
1477 // Get the output value corresponding to an input offset if we
1478 // couldn't find it in the hash table.
1479
1480 template<int size>
1481 typename elfcpp::Elf_types<size>::Elf_Addr
1482 Merged_symbol_value<size>::value_from_output_section(
1483     const Relobj* object,
1484     unsigned int input_shndx,
1485     typename elfcpp::Elf_types<size>::Elf_Addr input_offset) const
1486 {
1487   section_offset_type output_offset;
1488   bool found = object->merge_output_offset(input_shndx, input_offset,
1489                                            &output_offset);
1490
1491   // If this assertion fails, it means that some relocation was
1492   // against a portion of an input merge section which we didn't map
1493   // to the output file and we didn't explicitly discard.  We should
1494   // always map all portions of input merge sections.
1495   gold_assert(found);
1496
1497   if (output_offset == -1)
1498     return 0;
1499   else
1500     return this->output_start_address_ + output_offset;
1501 }
1502
1503 // Track_relocs methods.
1504
1505 // Initialize the class to track the relocs.  This gets the object,
1506 // the reloc section index, and the type of the relocs.  This returns
1507 // false if something goes wrong.
1508
1509 template<int size, bool big_endian>
1510 bool
1511 Track_relocs<size, big_endian>::initialize(
1512     Object* object,
1513     unsigned int reloc_shndx,
1514     unsigned int reloc_type)
1515 {
1516   // If RELOC_SHNDX is -1U, it means there is more than one reloc
1517   // section for the .eh_frame section.  We can't handle that case.
1518   if (reloc_shndx == -1U)
1519     return false;
1520
1521   // If RELOC_SHNDX is 0, there is no reloc section.
1522   if (reloc_shndx == 0)
1523     return true;
1524
1525   // Get the contents of the reloc section.
1526   this->prelocs_ = object->section_contents(reloc_shndx, &this->len_, false);
1527
1528   if (reloc_type == elfcpp::SHT_REL)
1529     this->reloc_size_ = elfcpp::Elf_sizes<size>::rel_size;
1530   else if (reloc_type == elfcpp::SHT_RELA)
1531     this->reloc_size_ = elfcpp::Elf_sizes<size>::rela_size;
1532   else
1533     gold_unreachable();
1534
1535   if (this->len_ % this->reloc_size_ != 0)
1536     {
1537       object->error(_("reloc section size %zu is not a multiple of "
1538                       "reloc size %d\n"),
1539                     static_cast<size_t>(this->len_),
1540                     this->reloc_size_);
1541       return false;
1542     }
1543
1544   return true;
1545 }
1546
1547 // Return the offset of the next reloc, or -1 if there isn't one.
1548
1549 template<int size, bool big_endian>
1550 off_t
1551 Track_relocs<size, big_endian>::next_offset() const
1552 {
1553   if (this->pos_ >= this->len_)
1554     return -1;
1555
1556   // Rel and Rela start out the same, so we can always use Rel to find
1557   // the r_offset value.
1558   elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1559   return rel.get_r_offset();
1560 }
1561
1562 // Return the index of the symbol referenced by the next reloc, or -1U
1563 // if there aren't any more relocs.
1564
1565 template<int size, bool big_endian>
1566 unsigned int
1567 Track_relocs<size, big_endian>::next_symndx() const
1568 {
1569   if (this->pos_ >= this->len_)
1570     return -1U;
1571   Sized_target<size, big_endian>* target
1572       = parameters->sized_target<size, big_endian>();
1573   return target->get_r_sym(this->prelocs_ + this->pos_);
1574 }
1575
1576 // Return the addend of the next reloc, or 0 if there isn't one.
1577
1578 template<int size, bool big_endian>
1579 uint64_t
1580 Track_relocs<size, big_endian>::next_addend() const
1581 {
1582   if (this->pos_ >= this->len_)
1583     return 0;
1584   if (this->reloc_size_ == elfcpp::Elf_sizes<size>::rel_size)
1585     return 0;
1586   elfcpp::Rela<size, big_endian> rela(this->prelocs_ + this->pos_);
1587   return rela.get_r_addend();
1588 }
1589
1590 // Advance to the next reloc whose r_offset is greater than or equal
1591 // to OFFSET.  Return the number of relocs we skip.
1592
1593 template<int size, bool big_endian>
1594 int
1595 Track_relocs<size, big_endian>::advance(off_t offset)
1596 {
1597   int ret = 0;
1598   while (this->pos_ < this->len_)
1599     {
1600       // Rel and Rela start out the same, so we can always use Rel to
1601       // find the r_offset value.
1602       elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1603       if (static_cast<off_t>(rel.get_r_offset()) >= offset)
1604         break;
1605       ++ret;
1606       this->pos_ += this->reloc_size_;
1607     }
1608   return ret;
1609 }
1610
1611 // Instantiate the templates we need.
1612
1613 #ifdef HAVE_TARGET_32_LITTLE
1614 template
1615 void
1616 Sized_relobj_file<32, false>::do_read_relocs(Read_relocs_data* rd);
1617 #endif
1618
1619 #ifdef HAVE_TARGET_32_BIG
1620 template
1621 void
1622 Sized_relobj_file<32, true>::do_read_relocs(Read_relocs_data* rd);
1623 #endif
1624
1625 #ifdef HAVE_TARGET_64_LITTLE
1626 template
1627 void
1628 Sized_relobj_file<64, false>::do_read_relocs(Read_relocs_data* rd);
1629 #endif
1630
1631 #ifdef HAVE_TARGET_64_BIG
1632 template
1633 void
1634 Sized_relobj_file<64, true>::do_read_relocs(Read_relocs_data* rd);
1635 #endif
1636
1637 #ifdef HAVE_TARGET_32_LITTLE
1638 template
1639 void
1640 Sized_relobj_file<32, false>::do_gc_process_relocs(Symbol_table* symtab,
1641                                                    Layout* layout,
1642                                                    Read_relocs_data* rd);
1643 #endif
1644
1645 #ifdef HAVE_TARGET_32_BIG
1646 template
1647 void
1648 Sized_relobj_file<32, true>::do_gc_process_relocs(Symbol_table* symtab,
1649                                                   Layout* layout,
1650                                                   Read_relocs_data* rd);
1651 #endif
1652
1653 #ifdef HAVE_TARGET_64_LITTLE
1654 template
1655 void
1656 Sized_relobj_file<64, false>::do_gc_process_relocs(Symbol_table* symtab,
1657                                                    Layout* layout,
1658                                                    Read_relocs_data* rd);
1659 #endif
1660
1661 #ifdef HAVE_TARGET_64_BIG
1662 template
1663 void
1664 Sized_relobj_file<64, true>::do_gc_process_relocs(Symbol_table* symtab,
1665                                                   Layout* layout,
1666                                                   Read_relocs_data* rd);
1667 #endif
1668
1669 #ifdef HAVE_TARGET_32_LITTLE
1670 template
1671 void
1672 Sized_relobj_file<32, false>::do_scan_relocs(Symbol_table* symtab,
1673                                              Layout* layout,
1674                                              Read_relocs_data* rd);
1675 #endif
1676
1677 #ifdef HAVE_TARGET_32_BIG
1678 template
1679 void
1680 Sized_relobj_file<32, true>::do_scan_relocs(Symbol_table* symtab,
1681                                             Layout* layout,
1682                                             Read_relocs_data* rd);
1683 #endif
1684
1685 #ifdef HAVE_TARGET_64_LITTLE
1686 template
1687 void
1688 Sized_relobj_file<64, false>::do_scan_relocs(Symbol_table* symtab,
1689                                              Layout* layout,
1690                                              Read_relocs_data* rd);
1691 #endif
1692
1693 #ifdef HAVE_TARGET_64_BIG
1694 template
1695 void
1696 Sized_relobj_file<64, true>::do_scan_relocs(Symbol_table* symtab,
1697                                             Layout* layout,
1698                                             Read_relocs_data* rd);
1699 #endif
1700
1701 #ifdef HAVE_TARGET_32_LITTLE
1702 template
1703 void
1704 Sized_relobj_file<32, false>::do_relocate(const Symbol_table* symtab,
1705                                           const Layout* layout,
1706                                           Output_file* of);
1707 #endif
1708
1709 #ifdef HAVE_TARGET_32_BIG
1710 template
1711 void
1712 Sized_relobj_file<32, true>::do_relocate(const Symbol_table* symtab,
1713                                          const Layout* layout,
1714                                          Output_file* of);
1715 #endif
1716
1717 #ifdef HAVE_TARGET_64_LITTLE
1718 template
1719 void
1720 Sized_relobj_file<64, false>::do_relocate(const Symbol_table* symtab,
1721                                           const Layout* layout,
1722                                           Output_file* of);
1723 #endif
1724
1725 #ifdef HAVE_TARGET_64_BIG
1726 template
1727 void
1728 Sized_relobj_file<64, true>::do_relocate(const Symbol_table* symtab,
1729                                          const Layout* layout,
1730                                          Output_file* of);
1731 #endif
1732
1733 #ifdef HAVE_TARGET_32_LITTLE
1734 template
1735 void
1736 Sized_relobj_file<32, false>::do_relocate_sections(
1737     const Symbol_table* symtab,
1738     const Layout* layout,
1739     const unsigned char* pshdrs,
1740     Output_file* of,
1741     Views* pviews);
1742
1743 template
1744 void
1745 Sized_relobj_file<32, false>::relocate_section_range(
1746     const Symbol_table* symtab,
1747     const Layout* layout,
1748     const unsigned char* pshdrs,
1749     Output_file* of,
1750     Views* pviews,
1751     unsigned int start_shndx,
1752     unsigned int end_shndx);
1753
1754 template
1755 unsigned char*
1756 Sized_relobj_file<32, false>::do_get_output_view(
1757     unsigned int shndx,
1758     section_size_type* plen) const;
1759 #endif
1760
1761 #ifdef HAVE_TARGET_32_BIG
1762 template
1763 void
1764 Sized_relobj_file<32, true>::do_relocate_sections(
1765     const Symbol_table* symtab,
1766     const Layout* layout,
1767     const unsigned char* pshdrs,
1768     Output_file* of,
1769     Views* pviews);
1770
1771 template
1772 void
1773 Sized_relobj_file<32, true>::relocate_section_range(
1774     const Symbol_table* symtab,
1775     const Layout* layout,
1776     const unsigned char* pshdrs,
1777     Output_file* of,
1778     Views* pviews,
1779     unsigned int start_shndx,
1780     unsigned int end_shndx);
1781
1782 template
1783 unsigned char*
1784 Sized_relobj_file<32, true>::do_get_output_view(
1785     unsigned int shndx,
1786     section_size_type* plen) const;
1787 #endif
1788
1789 #ifdef HAVE_TARGET_64_LITTLE
1790 template
1791 void
1792 Sized_relobj_file<64, false>::do_relocate_sections(
1793     const Symbol_table* symtab,
1794     const Layout* layout,
1795     const unsigned char* pshdrs,
1796     Output_file* of,
1797     Views* pviews);
1798
1799 template
1800 void
1801 Sized_relobj_file<64, false>::relocate_section_range(
1802     const Symbol_table* symtab,
1803     const Layout* layout,
1804     const unsigned char* pshdrs,
1805     Output_file* of,
1806     Views* pviews,
1807     unsigned int start_shndx,
1808     unsigned int end_shndx);
1809
1810 template
1811 unsigned char*
1812 Sized_relobj_file<64, false>::do_get_output_view(
1813     unsigned int shndx,
1814     section_size_type* plen) const;
1815 #endif
1816
1817 #ifdef HAVE_TARGET_64_BIG
1818 template
1819 void
1820 Sized_relobj_file<64, true>::do_relocate_sections(
1821     const Symbol_table* symtab,
1822     const Layout* layout,
1823     const unsigned char* pshdrs,
1824     Output_file* of,
1825     Views* pviews);
1826
1827 template
1828 void
1829 Sized_relobj_file<64, true>::relocate_section_range(
1830     const Symbol_table* symtab,
1831     const Layout* layout,
1832     const unsigned char* pshdrs,
1833     Output_file* of,
1834     Views* pviews,
1835     unsigned int start_shndx,
1836     unsigned int end_shndx);
1837
1838 template
1839 unsigned char*
1840 Sized_relobj_file<64, true>::do_get_output_view(
1841     unsigned int shndx,
1842     section_size_type* plen) const;
1843 #endif
1844
1845 #ifdef HAVE_TARGET_32_LITTLE
1846 template
1847 void
1848 Sized_relobj_file<32, false>::initialize_input_to_output_maps();
1849
1850 template
1851 void
1852 Sized_relobj_file<32, false>::free_input_to_output_maps();
1853 #endif
1854
1855 #ifdef HAVE_TARGET_32_BIG
1856 template
1857 void
1858 Sized_relobj_file<32, true>::initialize_input_to_output_maps();
1859
1860 template
1861 void
1862 Sized_relobj_file<32, true>::free_input_to_output_maps();
1863 #endif
1864
1865 #ifdef HAVE_TARGET_64_LITTLE
1866 template
1867 void
1868 Sized_relobj_file<64, false>::initialize_input_to_output_maps();
1869
1870 template
1871 void
1872 Sized_relobj_file<64, false>::free_input_to_output_maps();
1873 #endif
1874
1875 #ifdef HAVE_TARGET_64_BIG
1876 template
1877 void
1878 Sized_relobj_file<64, true>::initialize_input_to_output_maps();
1879
1880 template
1881 void
1882 Sized_relobj_file<64, true>::free_input_to_output_maps();
1883 #endif
1884
1885 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1886 template
1887 class Merged_symbol_value<32>;
1888 #endif
1889
1890 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1891 template
1892 class Merged_symbol_value<64>;
1893 #endif
1894
1895 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1896 template
1897 class Symbol_value<32>;
1898 #endif
1899
1900 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1901 template
1902 class Symbol_value<64>;
1903 #endif
1904
1905 #ifdef HAVE_TARGET_32_LITTLE
1906 template
1907 class Track_relocs<32, false>;
1908 #endif
1909
1910 #ifdef HAVE_TARGET_32_BIG
1911 template
1912 class Track_relocs<32, true>;
1913 #endif
1914
1915 #ifdef HAVE_TARGET_64_LITTLE
1916 template
1917 class Track_relocs<64, false>;
1918 #endif
1919
1920 #ifdef HAVE_TARGET_64_BIG
1921 template
1922 class Track_relocs<64, true>;
1923 #endif
1924
1925 } // End namespace gold.