1 // reloc.cc -- relocate input files for gold.
2 
3 // Copyright (C) 2006-2016 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   unsigned int shnum = this->shnum();
875   Sized_target<size, big_endian>* target =
876     parameters->sized_target<size, big_endian>();
877 
878   const Output_sections& out_sections(this->output_sections());
879   const std::vector<Address>& out_offsets(this->section_offsets());
880 
881   Relocate_info<size, big_endian> relinfo;
882   relinfo.symtab = symtab;
883   relinfo.layout = layout;
884   relinfo.object = this;
885 
886   const unsigned char* p = pshdrs + This::shdr_size;
887   for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
888     {
889       typename This::Shdr shdr(p);
890 
891       unsigned int sh_type = shdr.get_sh_type();
892       if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
893 	continue;
894 
895       off_t sh_size = shdr.get_sh_size();
896       if (sh_size == 0)
897 	continue;
898 
899       unsigned int index = this->adjust_shndx(shdr.get_sh_info());
900       if (index >= this->shnum())
901 	{
902 	  this->error(_("relocation section %u has bad info %u"),
903 		      i, index);
904 	  continue;
905 	}
906 
907       Output_section* os = out_sections[index];
908       if (os == NULL)
909 	{
910 	  // This relocation section is against a section which we
911 	  // discarded.
912 	  continue;
913 	}
914       Address output_offset = out_offsets[index];
915 
916       gold_assert((*pviews)[index].view != NULL);
917       if (parameters->options().relocatable())
918 	gold_assert((*pviews)[i].view != NULL);
919 
920       if (this->adjust_shndx(shdr.get_sh_link()) != this->symtab_shndx_)
921 	{
922 	  gold_error(_("relocation section %u uses unexpected "
923 		       "symbol table %u"),
924 		     i, this->adjust_shndx(shdr.get_sh_link()));
925 	  continue;
926 	}
927 
928       const unsigned char* prelocs = this->get_view(shdr.get_sh_offset(),
929 						    sh_size, true, false);
930 
931       unsigned int reloc_size;
932       if (sh_type == elfcpp::SHT_REL)
933 	reloc_size = elfcpp::Elf_sizes<size>::rel_size;
934       else
935 	reloc_size = elfcpp::Elf_sizes<size>::rela_size;
936 
937       if (reloc_size != shdr.get_sh_entsize())
938 	{
939 	  gold_error(_("unexpected entsize for reloc section %u: %lu != %u"),
940 		     i, static_cast<unsigned long>(shdr.get_sh_entsize()),
941 		     reloc_size);
942 	  continue;
943 	}
944 
945       size_t reloc_count = sh_size / reloc_size;
946       if (static_cast<off_t>(reloc_count * reloc_size) != sh_size)
947 	{
948 	  gold_error(_("reloc section %u size %lu uneven"),
949 		     i, static_cast<unsigned long>(sh_size));
950 	  continue;
951 	}
952 
953       gold_assert(output_offset != invalid_address
954 		  || this->relocs_must_follow_section_writes());
955 
956       relinfo.reloc_shndx = i;
957       relinfo.reloc_shdr = p;
958       relinfo.data_shndx = index;
959       relinfo.data_shdr = pshdrs + index * This::shdr_size;
960       unsigned char* view = (*pviews)[index].view;
961       Address address = (*pviews)[index].address;
962       section_size_type view_size = (*pviews)[index].view_size;
963 
964       Reloc_symbol_changes* reloc_map = NULL;
965       if (this->uses_split_stack() && output_offset != invalid_address)
966 	{
967 	  typename This::Shdr data_shdr(pshdrs + index * This::shdr_size);
968 	  if ((data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
969 	    this->split_stack_adjust(symtab, pshdrs, sh_type, index,
970 				     prelocs, reloc_count, view, view_size,
971 				     &reloc_map, target);
972 	}
973 
974       Relocatable_relocs* rr = NULL;
975       if (parameters->options().emit_relocs()
976 	  || parameters->options().relocatable())
977 	rr = this->relocatable_relocs(i);
978       relinfo.rr = rr;
979 
980       if (!parameters->options().relocatable())
981 	{
982 	  target->relocate_section(&relinfo, sh_type, prelocs, reloc_count, os,
983 				   output_offset == invalid_address,
984 				   view, address, view_size, reloc_map);
985 	  if (parameters->options().emit_relocs())
986 	    target->relocate_relocs(&relinfo, sh_type, prelocs, reloc_count,
987 				    os, output_offset,
988 				    view, address, view_size,
989 				    (*pviews)[i].view,
990 				    (*pviews)[i].view_size);
991 	  if (parameters->incremental())
992 	    this->incremental_relocs_write(&relinfo, sh_type, prelocs,
993 					   reloc_count, os, output_offset, of);
994 	}
995       else
996 	target->relocate_relocs(&relinfo, sh_type, prelocs, reloc_count,
997 				os, output_offset,
998 				view, address, view_size,
999 				(*pviews)[i].view,
1000 				(*pviews)[i].view_size);
1001     }
1002 }
1003 
1004 // Return the output view for section SHNDX.
1005 
1006 template<int size, bool big_endian>
1007 unsigned char*
1008 Sized_relobj_file<size, big_endian>::do_get_output_view(
1009     unsigned int shndx,
1010     section_size_type* plen) const
1011 {
1012   gold_assert(this->output_views_ != NULL);
1013   gold_assert(shndx < this->output_views_->size());
1014   const View_size& v = (*this->output_views_)[shndx];
1015   *plen = v.view_size;
1016   return v.view;
1017 }
1018 
1019 // Write the incremental relocs.
1020 
1021 template<int size, bool big_endian>
1022 void
1023 Sized_relobj_file<size, big_endian>::incremental_relocs_write(
1024     const Relocate_info<size, big_endian>* relinfo,
1025     unsigned int sh_type,
1026     const unsigned char* prelocs,
1027     size_t reloc_count,
1028     Output_section* output_section,
1029     Address output_offset,
1030     Output_file* of)
1031 {
1032   if (sh_type == elfcpp::SHT_REL)
1033     this->incremental_relocs_write_reltype<elfcpp::SHT_REL>(
1034 	relinfo,
1035 	prelocs,
1036 	reloc_count,
1037 	output_section,
1038 	output_offset,
1039 	of);
1040   else
1041     {
1042       gold_assert(sh_type == elfcpp::SHT_RELA);
1043       this->incremental_relocs_write_reltype<elfcpp::SHT_RELA>(
1044 	  relinfo,
1045 	  prelocs,
1046 	  reloc_count,
1047 	  output_section,
1048 	  output_offset,
1049 	  of);
1050     }
1051 }
1052 
1053 // Write the incremental relocs, templatized on the type of the
1054 // relocation section.
1055 
1056 template<int size, bool big_endian>
1057 template<int sh_type>
1058 void
1059 Sized_relobj_file<size, big_endian>::incremental_relocs_write_reltype(
1060     const Relocate_info<size, big_endian>* relinfo,
1061     const unsigned char* prelocs,
1062     size_t reloc_count,
1063     Output_section* output_section,
1064     Address output_offset,
1065     Output_file* of)
1066 {
1067   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reloc;
1068   const unsigned int reloc_size =
1069       Reloc_types<sh_type, size, big_endian>::reloc_size;
1070   const unsigned int sizeof_addr = size / 8;
1071   const unsigned int incr_reloc_size =
1072       Incremental_relocs_reader<size, big_endian>::reloc_size;
1073 
1074   unsigned int out_shndx = output_section->out_shndx();
1075 
1076   // Get a view for the .gnu_incremental_relocs section.
1077 
1078   Incremental_inputs* inputs = relinfo->layout->incremental_inputs();
1079   gold_assert(inputs != NULL);
1080   const off_t relocs_off = inputs->relocs_section()->offset();
1081   const off_t relocs_size = inputs->relocs_section()->data_size();
1082   unsigned char* const view = of->get_output_view(relocs_off, relocs_size);
1083 
1084   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
1085     {
1086       Reloc reloc(prelocs);
1087 
1088       // FIXME: Some targets have a non-standard r_info field.
1089       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
1090       const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
1091       const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
1092 
1093       if (r_sym < this->local_symbol_count_)
1094         continue;
1095 
1096       // Get the new offset--the location in the output section where
1097       // this relocation should be applied.
1098 
1099       Address offset = reloc.get_r_offset();
1100       if (output_offset != invalid_address)
1101 	offset += output_offset;
1102       else
1103 	{
1104           section_offset_type sot_offset =
1105               convert_types<section_offset_type, Address>(offset);
1106 	  section_offset_type new_sot_offset =
1107 	      output_section->output_offset(relinfo->object,
1108 					    relinfo->data_shndx,
1109 					    sot_offset);
1110 	  gold_assert(new_sot_offset != -1);
1111 	  offset += new_sot_offset;
1112 	}
1113 
1114       // Get the addend.
1115       typename elfcpp::Elf_types<size>::Elf_Swxword addend;
1116       if (sh_type == elfcpp::SHT_RELA)
1117 	addend =
1118 	    Reloc_types<sh_type, size, big_endian>::get_reloc_addend(&reloc);
1119       else
1120         {
1121           // FIXME: Get the addend for SHT_REL.
1122           addend = 0;
1123         }
1124 
1125       // Get the index of the output relocation.
1126 
1127       unsigned int reloc_index =
1128           this->next_incremental_reloc_index(r_sym - this->local_symbol_count_);
1129 
1130       // Write the relocation.
1131 
1132       unsigned char* pov = view + reloc_index * incr_reloc_size;
1133       elfcpp::Swap<32, big_endian>::writeval(pov, r_type);
1134       elfcpp::Swap<32, big_endian>::writeval(pov + 4, out_shndx);
1135       elfcpp::Swap<size, big_endian>::writeval(pov + 8, offset);
1136       elfcpp::Swap<size, big_endian>::writeval(pov + 8 + sizeof_addr, addend);
1137       of->write_output_view(pov - view, incr_reloc_size, view);
1138     }
1139 }
1140 
1141 // Create merge hash tables for the local symbols.  These are used to
1142 // speed up relocations.
1143 
1144 template<int size, bool big_endian>
1145 void
1146 Sized_relobj_file<size, big_endian>::initialize_input_to_output_maps()
1147 {
1148   const unsigned int loccount = this->local_symbol_count_;
1149   for (unsigned int i = 1; i < loccount; ++i)
1150     {
1151       Symbol_value<size>& lv(this->local_values_[i]);
1152       lv.initialize_input_to_output_map(this);
1153     }
1154 }
1155 
1156 // Free merge hash tables for the local symbols.
1157 
1158 template<int size, bool big_endian>
1159 void
1160 Sized_relobj_file<size, big_endian>::free_input_to_output_maps()
1161 {
1162   const unsigned int loccount = this->local_symbol_count_;
1163   for (unsigned int i = 1; i < loccount; ++i)
1164     {
1165       Symbol_value<size>& lv(this->local_values_[i]);
1166       lv.free_input_to_output_map();
1167     }
1168 }
1169 
1170 // If an object was compiled with -fsplit-stack, this is called to
1171 // check whether any relocations refer to functions defined in objects
1172 // which were not compiled with -fsplit-stack.  If they were, then we
1173 // need to apply some target-specific adjustments to request
1174 // additional stack space.
1175 
1176 template<int size, bool big_endian>
1177 void
1178 Sized_relobj_file<size, big_endian>::split_stack_adjust(
1179     const Symbol_table* symtab,
1180     const unsigned char* pshdrs,
1181     unsigned int sh_type,
1182     unsigned int shndx,
1183     const unsigned char* prelocs,
1184     size_t reloc_count,
1185     unsigned char* view,
1186     section_size_type view_size,
1187     Reloc_symbol_changes** reloc_map,
1188     const Sized_target<size, big_endian>* target)
1189 {
1190   if (sh_type == elfcpp::SHT_REL)
1191     this->split_stack_adjust_reltype<elfcpp::SHT_REL>(symtab, pshdrs, shndx,
1192 						      prelocs, reloc_count,
1193 						      view, view_size,
1194 						      reloc_map, target);
1195   else
1196     {
1197       gold_assert(sh_type == elfcpp::SHT_RELA);
1198       this->split_stack_adjust_reltype<elfcpp::SHT_RELA>(symtab, pshdrs, shndx,
1199 							 prelocs, reloc_count,
1200 							 view, view_size,
1201 							 reloc_map, target);
1202     }
1203 }
1204 
1205 // Adjust for -fsplit-stack, templatized on the type of the relocation
1206 // section.
1207 
1208 template<int size, bool big_endian>
1209 template<int sh_type>
1210 void
1211 Sized_relobj_file<size, big_endian>::split_stack_adjust_reltype(
1212     const Symbol_table* symtab,
1213     const unsigned char* pshdrs,
1214     unsigned int shndx,
1215     const unsigned char* prelocs,
1216     size_t reloc_count,
1217     unsigned char* view,
1218     section_size_type view_size,
1219     Reloc_symbol_changes** reloc_map,
1220     const Sized_target<size, big_endian>* target)
1221 {
1222   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
1223   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
1224 
1225   size_t local_count = this->local_symbol_count();
1226 
1227   std::vector<section_offset_type> non_split_refs;
1228 
1229   const unsigned char* pr = prelocs;
1230   for (size_t i = 0; i < reloc_count; ++i, pr += reloc_size)
1231     {
1232       // Some supported targets have a non-standard r_info field.
1233       // If this call is too slow, we can move this routine to
1234       // target-reloc.h and templatize it on Classify_reloc.
1235       unsigned int r_sym = target->get_r_sym(pr);
1236       if (r_sym < local_count)
1237 	continue;
1238 
1239       const Symbol* gsym = this->global_symbol(r_sym);
1240       gold_assert(gsym != NULL);
1241       if (gsym->is_forwarder())
1242 	gsym = symtab->resolve_forwards(gsym);
1243 
1244       // See if this relocation refers to a function defined in an
1245       // object compiled without -fsplit-stack.  Note that we don't
1246       // care about the type of relocation--this means that in some
1247       // cases we will ask for a large stack unnecessarily, but this
1248       // is not fatal.  FIXME: Some targets have symbols which are
1249       // functions but are not type STT_FUNC, e.g., STT_ARM_TFUNC.
1250       if (!gsym->is_undefined()
1251 	  && gsym->source() == Symbol::FROM_OBJECT
1252 	  && !gsym->object()->uses_split_stack())
1253 	{
1254 	  if (parameters->target().is_call_to_non_split(gsym, pr, view,
1255 							view_size))
1256 	    {
1257 	      Reltype reloc(pr);
1258 	      section_offset_type offset =
1259 		convert_to_section_size_type(reloc.get_r_offset());
1260 	      non_split_refs.push_back(offset);
1261 	    }
1262 	}
1263     }
1264 
1265   if (non_split_refs.empty())
1266     return;
1267 
1268   // At this point, every entry in NON_SPLIT_REFS indicates a
1269   // relocation which refers to a function in an object compiled
1270   // without -fsplit-stack.  We now have to convert that list into a
1271   // set of offsets to functions.  First, we find all the functions.
1272 
1273   Function_offsets function_offsets;
1274   this->find_functions(pshdrs, shndx, &function_offsets);
1275   if (function_offsets.empty())
1276     return;
1277 
1278   // Now get a list of the function with references to non split-stack
1279   // code.
1280 
1281   Function_offsets calls_non_split;
1282   for (std::vector<section_offset_type>::const_iterator p
1283 	 = non_split_refs.begin();
1284        p != non_split_refs.end();
1285        ++p)
1286     {
1287       Function_offsets::const_iterator low = function_offsets.lower_bound(*p);
1288       if (low == function_offsets.end())
1289 	--low;
1290       else if (low->first == *p)
1291 	;
1292       else if (low == function_offsets.begin())
1293 	continue;
1294       else
1295 	--low;
1296 
1297       calls_non_split.insert(*low);
1298     }
1299   if (calls_non_split.empty())
1300     return;
1301 
1302   // Now we have a set of functions to adjust.  The adjustments are
1303   // target specific.  Besides changing the output section view
1304   // however, it likes, the target may request a relocation change
1305   // from one global symbol name to another.
1306 
1307   for (Function_offsets::const_iterator p = calls_non_split.begin();
1308        p != calls_non_split.end();
1309        ++p)
1310     {
1311       std::string from;
1312       std::string to;
1313       parameters->target().calls_non_split(this, shndx, p->first, p->second,
1314 					   prelocs, reloc_count,
1315 					   view, view_size, &from, &to);
1316       if (!from.empty())
1317 	{
1318 	  gold_assert(!to.empty());
1319 	  Symbol* tosym = NULL;
1320 
1321 	  // Find relocations in the relevant function which are for
1322 	  // FROM.
1323 	  pr = prelocs;
1324 	  for (size_t i = 0; i < reloc_count; ++i, pr += reloc_size)
1325 	    {
1326 	      Reltype reloc(pr);
1327 
1328 	      unsigned int r_sym = target->get_r_sym(pr);
1329 	      if (r_sym < local_count)
1330 		continue;
1331 
1332 	      section_offset_type offset =
1333 		convert_to_section_size_type(reloc.get_r_offset());
1334 	      if (offset < p->first
1335 		  || (offset
1336 		      >= (p->first
1337 			  + static_cast<section_offset_type>(p->second))))
1338 		continue;
1339 
1340 	      const Symbol* gsym = this->global_symbol(r_sym);
1341 	      if (from == gsym->name())
1342 		{
1343 		  if (tosym == NULL)
1344 		    {
1345 		      tosym = symtab->lookup(to.c_str());
1346 		      if (tosym == NULL)
1347 			{
1348 			  this->error(_("could not convert call "
1349 					"to '%s' to '%s'"),
1350 				      from.c_str(), to.c_str());
1351 			  break;
1352 			}
1353 		    }
1354 
1355 		  if (*reloc_map == NULL)
1356 		    *reloc_map = new Reloc_symbol_changes(reloc_count);
1357 		  (*reloc_map)->set(i, tosym);
1358 		}
1359 	    }
1360 	}
1361     }
1362 }
1363 
1364 // Find all the function in this object defined in section SHNDX.
1365 // Store their offsets in the section in FUNCTION_OFFSETS.
1366 
1367 template<int size, bool big_endian>
1368 void
1369 Sized_relobj_file<size, big_endian>::find_functions(
1370     const unsigned char* pshdrs,
1371     unsigned int shndx,
1372     Sized_relobj_file<size, big_endian>::Function_offsets* function_offsets)
1373 {
1374   // We need to read the symbols to find the functions.  If we wanted
1375   // to, we could cache reading the symbols across all sections in the
1376   // object.
1377   const unsigned int symtab_shndx = this->symtab_shndx_;
1378   typename This::Shdr symtabshdr(pshdrs + symtab_shndx * This::shdr_size);
1379   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
1380 
1381   typename elfcpp::Elf_types<size>::Elf_WXword sh_size =
1382     symtabshdr.get_sh_size();
1383   const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
1384 					      sh_size, true, true);
1385 
1386   const int sym_size = This::sym_size;
1387   const unsigned int symcount = sh_size / sym_size;
1388   for (unsigned int i = 0; i < symcount; ++i, psyms += sym_size)
1389     {
1390       typename elfcpp::Sym<size, big_endian> isym(psyms);
1391 
1392       // FIXME: Some targets can have functions which do not have type
1393       // STT_FUNC, e.g., STT_ARM_TFUNC.
1394       if (isym.get_st_type() != elfcpp::STT_FUNC
1395 	  || isym.get_st_size() == 0)
1396 	continue;
1397 
1398       bool is_ordinary;
1399       Symbol_location loc;
1400       loc.shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
1401 					 &is_ordinary);
1402       if (!is_ordinary)
1403 	continue;
1404 
1405       loc.object = this;
1406       loc.offset = isym.get_st_value();
1407       parameters->target().function_location(&loc);
1408 
1409       if (loc.shndx != shndx)
1410 	continue;
1411 
1412       section_offset_type value =
1413 	convert_to_section_size_type(loc.offset);
1414       section_size_type fnsize =
1415 	convert_to_section_size_type(isym.get_st_size());
1416 
1417       (*function_offsets)[value] = fnsize;
1418     }
1419 }
1420 
1421 // Reverse the words in a section.  Used for .ctors sections mapped to
1422 // .init_array sections.  See ctors_sections_in_init_array in
1423 // layout.cc.
1424 
1425 template<int size, bool big_endian>
1426 void
1427 Sized_relobj_file<size, big_endian>::reverse_words(unsigned char* view,
1428 						   section_size_type view_size)
1429 {
1430   typedef typename elfcpp::Swap<size, big_endian>::Valtype Valtype;
1431   Valtype* vview = reinterpret_cast<Valtype*>(view);
1432   section_size_type vview_size = view_size / (size / 8);
1433   for (section_size_type i = 0; i < vview_size / 2; ++i)
1434     {
1435       Valtype tmp = vview[i];
1436       vview[i] = vview[vview_size - 1 - i];
1437       vview[vview_size - 1 - i] = tmp;
1438     }
1439 }
1440 
1441 // Class Merged_symbol_value.
1442 
1443 template<int size>
1444 void
1445 Merged_symbol_value<size>::initialize_input_to_output_map(
1446     const Relobj* object,
1447     unsigned int input_shndx)
1448 {
1449   object->initialize_input_to_output_map<size>(input_shndx,
1450 					       this->output_start_address_,
1451 					       &this->output_addresses_);
1452 }
1453 
1454 // Get the output value corresponding to an input offset if we
1455 // couldn't find it in the hash table.
1456 
1457 template<int size>
1458 typename elfcpp::Elf_types<size>::Elf_Addr
1459 Merged_symbol_value<size>::value_from_output_section(
1460     const Relobj* object,
1461     unsigned int input_shndx,
1462     typename elfcpp::Elf_types<size>::Elf_Addr input_offset) const
1463 {
1464   section_offset_type output_offset;
1465   bool found = object->merge_output_offset(input_shndx, input_offset,
1466 					   &output_offset);
1467 
1468   // If this assertion fails, it means that some relocation was
1469   // against a portion of an input merge section which we didn't map
1470   // to the output file and we didn't explicitly discard.  We should
1471   // always map all portions of input merge sections.
1472   gold_assert(found);
1473 
1474   if (output_offset == -1)
1475     return 0;
1476   else
1477     return this->output_start_address_ + output_offset;
1478 }
1479 
1480 // Track_relocs methods.
1481 
1482 // Initialize the class to track the relocs.  This gets the object,
1483 // the reloc section index, and the type of the relocs.  This returns
1484 // false if something goes wrong.
1485 
1486 template<int size, bool big_endian>
1487 bool
1488 Track_relocs<size, big_endian>::initialize(
1489     Object* object,
1490     unsigned int reloc_shndx,
1491     unsigned int reloc_type)
1492 {
1493   // If RELOC_SHNDX is -1U, it means there is more than one reloc
1494   // section for the .eh_frame section.  We can't handle that case.
1495   if (reloc_shndx == -1U)
1496     return false;
1497 
1498   // If RELOC_SHNDX is 0, there is no reloc section.
1499   if (reloc_shndx == 0)
1500     return true;
1501 
1502   // Get the contents of the reloc section.
1503   this->prelocs_ = object->section_contents(reloc_shndx, &this->len_, false);
1504 
1505   if (reloc_type == elfcpp::SHT_REL)
1506     this->reloc_size_ = elfcpp::Elf_sizes<size>::rel_size;
1507   else if (reloc_type == elfcpp::SHT_RELA)
1508     this->reloc_size_ = elfcpp::Elf_sizes<size>::rela_size;
1509   else
1510     gold_unreachable();
1511 
1512   if (this->len_ % this->reloc_size_ != 0)
1513     {
1514       object->error(_("reloc section size %zu is not a multiple of "
1515 		      "reloc size %d\n"),
1516 		    static_cast<size_t>(this->len_),
1517 		    this->reloc_size_);
1518       return false;
1519     }
1520 
1521   return true;
1522 }
1523 
1524 // Return the offset of the next reloc, or -1 if there isn't one.
1525 
1526 template<int size, bool big_endian>
1527 off_t
1528 Track_relocs<size, big_endian>::next_offset() const
1529 {
1530   if (this->pos_ >= this->len_)
1531     return -1;
1532 
1533   // Rel and Rela start out the same, so we can always use Rel to find
1534   // the r_offset value.
1535   elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1536   return rel.get_r_offset();
1537 }
1538 
1539 // Return the index of the symbol referenced by the next reloc, or -1U
1540 // if there aren't any more relocs.
1541 
1542 template<int size, bool big_endian>
1543 unsigned int
1544 Track_relocs<size, big_endian>::next_symndx() const
1545 {
1546   if (this->pos_ >= this->len_)
1547     return -1U;
1548   Sized_target<size, big_endian>* target
1549       = parameters->sized_target<size, big_endian>();
1550   return target->get_r_sym(this->prelocs_ + this->pos_);
1551 }
1552 
1553 // Return the addend of the next reloc, or 0 if there isn't one.
1554 
1555 template<int size, bool big_endian>
1556 uint64_t
1557 Track_relocs<size, big_endian>::next_addend() const
1558 {
1559   if (this->pos_ >= this->len_)
1560     return 0;
1561   if (this->reloc_size_ == elfcpp::Elf_sizes<size>::rel_size)
1562     return 0;
1563   elfcpp::Rela<size, big_endian> rela(this->prelocs_ + this->pos_);
1564   return rela.get_r_addend();
1565 }
1566 
1567 // Advance to the next reloc whose r_offset is greater than or equal
1568 // to OFFSET.  Return the number of relocs we skip.
1569 
1570 template<int size, bool big_endian>
1571 int
1572 Track_relocs<size, big_endian>::advance(off_t offset)
1573 {
1574   int ret = 0;
1575   while (this->pos_ < this->len_)
1576     {
1577       // Rel and Rela start out the same, so we can always use Rel to
1578       // find the r_offset value.
1579       elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1580       if (static_cast<off_t>(rel.get_r_offset()) >= offset)
1581 	break;
1582       ++ret;
1583       this->pos_ += this->reloc_size_;
1584     }
1585   return ret;
1586 }
1587 
1588 // Instantiate the templates we need.
1589 
1590 #ifdef HAVE_TARGET_32_LITTLE
1591 template
1592 void
1593 Sized_relobj_file<32, false>::do_read_relocs(Read_relocs_data* rd);
1594 #endif
1595 
1596 #ifdef HAVE_TARGET_32_BIG
1597 template
1598 void
1599 Sized_relobj_file<32, true>::do_read_relocs(Read_relocs_data* rd);
1600 #endif
1601 
1602 #ifdef HAVE_TARGET_64_LITTLE
1603 template
1604 void
1605 Sized_relobj_file<64, false>::do_read_relocs(Read_relocs_data* rd);
1606 #endif
1607 
1608 #ifdef HAVE_TARGET_64_BIG
1609 template
1610 void
1611 Sized_relobj_file<64, true>::do_read_relocs(Read_relocs_data* rd);
1612 #endif
1613 
1614 #ifdef HAVE_TARGET_32_LITTLE
1615 template
1616 void
1617 Sized_relobj_file<32, false>::do_gc_process_relocs(Symbol_table* symtab,
1618 						   Layout* layout,
1619 						   Read_relocs_data* rd);
1620 #endif
1621 
1622 #ifdef HAVE_TARGET_32_BIG
1623 template
1624 void
1625 Sized_relobj_file<32, true>::do_gc_process_relocs(Symbol_table* symtab,
1626 						  Layout* layout,
1627 						  Read_relocs_data* rd);
1628 #endif
1629 
1630 #ifdef HAVE_TARGET_64_LITTLE
1631 template
1632 void
1633 Sized_relobj_file<64, false>::do_gc_process_relocs(Symbol_table* symtab,
1634 						   Layout* layout,
1635 						   Read_relocs_data* rd);
1636 #endif
1637 
1638 #ifdef HAVE_TARGET_64_BIG
1639 template
1640 void
1641 Sized_relobj_file<64, true>::do_gc_process_relocs(Symbol_table* symtab,
1642 						  Layout* layout,
1643 						  Read_relocs_data* rd);
1644 #endif
1645 
1646 #ifdef HAVE_TARGET_32_LITTLE
1647 template
1648 void
1649 Sized_relobj_file<32, false>::do_scan_relocs(Symbol_table* symtab,
1650 					     Layout* layout,
1651 					     Read_relocs_data* rd);
1652 #endif
1653 
1654 #ifdef HAVE_TARGET_32_BIG
1655 template
1656 void
1657 Sized_relobj_file<32, true>::do_scan_relocs(Symbol_table* symtab,
1658 					    Layout* layout,
1659 					    Read_relocs_data* rd);
1660 #endif
1661 
1662 #ifdef HAVE_TARGET_64_LITTLE
1663 template
1664 void
1665 Sized_relobj_file<64, false>::do_scan_relocs(Symbol_table* symtab,
1666 					     Layout* layout,
1667 					     Read_relocs_data* rd);
1668 #endif
1669 
1670 #ifdef HAVE_TARGET_64_BIG
1671 template
1672 void
1673 Sized_relobj_file<64, true>::do_scan_relocs(Symbol_table* symtab,
1674 					    Layout* layout,
1675 					    Read_relocs_data* rd);
1676 #endif
1677 
1678 #ifdef HAVE_TARGET_32_LITTLE
1679 template
1680 void
1681 Sized_relobj_file<32, false>::do_relocate(const Symbol_table* symtab,
1682 					  const Layout* layout,
1683 					  Output_file* of);
1684 #endif
1685 
1686 #ifdef HAVE_TARGET_32_BIG
1687 template
1688 void
1689 Sized_relobj_file<32, true>::do_relocate(const Symbol_table* symtab,
1690 					 const Layout* layout,
1691 					 Output_file* of);
1692 #endif
1693 
1694 #ifdef HAVE_TARGET_64_LITTLE
1695 template
1696 void
1697 Sized_relobj_file<64, false>::do_relocate(const Symbol_table* symtab,
1698 					  const Layout* layout,
1699 					  Output_file* of);
1700 #endif
1701 
1702 #ifdef HAVE_TARGET_64_BIG
1703 template
1704 void
1705 Sized_relobj_file<64, true>::do_relocate(const Symbol_table* symtab,
1706 					 const Layout* layout,
1707 					 Output_file* of);
1708 #endif
1709 
1710 #ifdef HAVE_TARGET_32_LITTLE
1711 template
1712 void
1713 Sized_relobj_file<32, false>::do_relocate_sections(
1714     const Symbol_table* symtab,
1715     const Layout* layout,
1716     const unsigned char* pshdrs,
1717     Output_file* of,
1718     Views* pviews);
1719 
1720 template
1721 unsigned char*
1722 Sized_relobj_file<32, false>::do_get_output_view(
1723     unsigned int shndx,
1724     section_size_type* plen) const;
1725 #endif
1726 
1727 #ifdef HAVE_TARGET_32_BIG
1728 template
1729 void
1730 Sized_relobj_file<32, true>::do_relocate_sections(
1731     const Symbol_table* symtab,
1732     const Layout* layout,
1733     const unsigned char* pshdrs,
1734     Output_file* of,
1735     Views* pviews);
1736 
1737 template
1738 unsigned char*
1739 Sized_relobj_file<32, true>::do_get_output_view(
1740     unsigned int shndx,
1741     section_size_type* plen) const;
1742 #endif
1743 
1744 #ifdef HAVE_TARGET_64_LITTLE
1745 template
1746 void
1747 Sized_relobj_file<64, false>::do_relocate_sections(
1748     const Symbol_table* symtab,
1749     const Layout* layout,
1750     const unsigned char* pshdrs,
1751     Output_file* of,
1752     Views* pviews);
1753 
1754 template
1755 unsigned char*
1756 Sized_relobj_file<64, false>::do_get_output_view(
1757     unsigned int shndx,
1758     section_size_type* plen) const;
1759 #endif
1760 
1761 #ifdef HAVE_TARGET_64_BIG
1762 template
1763 void
1764 Sized_relobj_file<64, 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 unsigned char*
1773 Sized_relobj_file<64, true>::do_get_output_view(
1774     unsigned int shndx,
1775     section_size_type* plen) const;
1776 #endif
1777 
1778 #ifdef HAVE_TARGET_32_LITTLE
1779 template
1780 void
1781 Sized_relobj_file<32, false>::initialize_input_to_output_maps();
1782 
1783 template
1784 void
1785 Sized_relobj_file<32, false>::free_input_to_output_maps();
1786 #endif
1787 
1788 #ifdef HAVE_TARGET_32_BIG
1789 template
1790 void
1791 Sized_relobj_file<32, true>::initialize_input_to_output_maps();
1792 
1793 template
1794 void
1795 Sized_relobj_file<32, true>::free_input_to_output_maps();
1796 #endif
1797 
1798 #ifdef HAVE_TARGET_64_LITTLE
1799 template
1800 void
1801 Sized_relobj_file<64, false>::initialize_input_to_output_maps();
1802 
1803 template
1804 void
1805 Sized_relobj_file<64, false>::free_input_to_output_maps();
1806 #endif
1807 
1808 #ifdef HAVE_TARGET_64_BIG
1809 template
1810 void
1811 Sized_relobj_file<64, true>::initialize_input_to_output_maps();
1812 
1813 template
1814 void
1815 Sized_relobj_file<64, true>::free_input_to_output_maps();
1816 #endif
1817 
1818 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1819 template
1820 class Merged_symbol_value<32>;
1821 #endif
1822 
1823 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1824 template
1825 class Merged_symbol_value<64>;
1826 #endif
1827 
1828 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1829 template
1830 class Symbol_value<32>;
1831 #endif
1832 
1833 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1834 template
1835 class Symbol_value<64>;
1836 #endif
1837 
1838 #ifdef HAVE_TARGET_32_LITTLE
1839 template
1840 class Track_relocs<32, false>;
1841 #endif
1842 
1843 #ifdef HAVE_TARGET_32_BIG
1844 template
1845 class Track_relocs<32, true>;
1846 #endif
1847 
1848 #ifdef HAVE_TARGET_64_LITTLE
1849 template
1850 class Track_relocs<64, false>;
1851 #endif
1852 
1853 #ifdef HAVE_TARGET_64_BIG
1854 template
1855 class Track_relocs<64, true>;
1856 #endif
1857 
1858 } // End namespace gold.
1859