1 // reloc.cc -- relocate input files for gold.
2 
3 // Copyright (C) 2006-2014 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*
is_runnable()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
locks(Task_locker * tl)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
run(Workqueue * workqueue)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
get_name() const98 Read_relocs::get_name() const
99 {
100   return "Read_relocs " + this->object_->name();
101 }
102 
103 // Gc_process_relocs methods.
104 
~Gc_process_relocs()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*
is_runnable()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
locks(Task_locker * tl)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
run(Workqueue *)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
get_name() const143 Gc_process_relocs::get_name() const
144 {
145   return "Gc_process_relocs " + this->object_->name();
146 }
147 
148 // Scan_relocs methods.
149 
~Scan_relocs()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*
is_runnable()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
locks(Task_locker * tl)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
run(Workqueue *)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
get_name() const197 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*
is_runnable()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
locks(Task_locker * tl)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
run(Workqueue *)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
get_name() const251 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
do_read_relocs(Read_relocs_data * rd)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
do_gc_process_relocs(Symbol_table * symtab,Layout * layout,Read_relocs_data * rd)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
do_scan_relocs(Symbol_table * symtab,Layout * layout,Read_relocs_data * rd)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 // This is a strategy class we use when scanning for --emit-relocs.
505 
506 template<int sh_type>
507 class Emit_relocs_strategy
508 {
509  public:
510   // A local non-section symbol.
511   inline Relocatable_relocs::Reloc_strategy
local_non_section_strategy(unsigned int,Relobj *,unsigned int)512   local_non_section_strategy(unsigned int, Relobj*, unsigned int)
513   { return Relocatable_relocs::RELOC_COPY; }
514 
515   // A local section symbol.
516   inline Relocatable_relocs::Reloc_strategy
local_section_strategy(unsigned int,Relobj *)517   local_section_strategy(unsigned int, Relobj*)
518   {
519     if (sh_type == elfcpp::SHT_RELA)
520       return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA;
521     else
522       {
523 	// The addend is stored in the section contents.  Since this
524 	// is not a relocatable link, we are going to apply the
525 	// relocation contents to the section as usual.  This means
526 	// that we have no way to record the original addend.  If the
527 	// original addend is not zero, there is basically no way for
528 	// the user to handle this correctly.  Caveat emptor.
529 	return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0;
530       }
531   }
532 
533   // A global symbol.
534   inline Relocatable_relocs::Reloc_strategy
global_strategy(unsigned int,Relobj *,unsigned int)535   global_strategy(unsigned int, Relobj*, unsigned int)
536   { return Relocatable_relocs::RELOC_COPY; }
537 };
538 
539 // Scan the input relocations for --emit-relocs.
540 
541 template<int size, bool big_endian>
542 void
emit_relocs_scan(Symbol_table * symtab,Layout * layout,const unsigned char * plocal_syms,const Read_relocs_data::Relocs_list::iterator & p)543 Sized_relobj_file<size, big_endian>::emit_relocs_scan(
544     Symbol_table* symtab,
545     Layout* layout,
546     const unsigned char* plocal_syms,
547     const Read_relocs_data::Relocs_list::iterator& p)
548 {
549   Relocatable_relocs* rr = this->relocatable_relocs(p->reloc_shndx);
550   gold_assert(rr != NULL);
551   rr->set_reloc_count(p->reloc_count);
552 
553   if (p->sh_type == elfcpp::SHT_REL)
554     this->emit_relocs_scan_reltype<elfcpp::SHT_REL>(symtab, layout,
555 						    plocal_syms, p, rr);
556   else
557     {
558       gold_assert(p->sh_type == elfcpp::SHT_RELA);
559       this->emit_relocs_scan_reltype<elfcpp::SHT_RELA>(symtab, layout,
560 						       plocal_syms, p, rr);
561     }
562 }
563 
564 // Scan the input relocation for --emit-relocs, templatized on the
565 // type of the relocation section.
566 
567 template<int size, bool big_endian>
568 template<int sh_type>
569 void
emit_relocs_scan_reltype(Symbol_table * symtab,Layout * layout,const unsigned char * plocal_syms,const Read_relocs_data::Relocs_list::iterator & p,Relocatable_relocs * rr)570 Sized_relobj_file<size, big_endian>::emit_relocs_scan_reltype(
571     Symbol_table* symtab,
572     Layout* layout,
573     const unsigned char* plocal_syms,
574     const Read_relocs_data::Relocs_list::iterator& p,
575     Relocatable_relocs* rr)
576 {
577   scan_relocatable_relocs<size, big_endian, sh_type,
578 			  Emit_relocs_strategy<sh_type> >(
579     symtab,
580     layout,
581     this,
582     p->data_shndx,
583     p->contents->data(),
584     p->reloc_count,
585     p->output_section,
586     p->needs_special_offset_handling,
587     this->local_symbol_count_,
588     plocal_syms,
589     rr);
590 }
591 
592 // Scan the input relocations for --incremental.
593 
594 template<int size, bool big_endian>
595 void
incremental_relocs_scan(const Read_relocs_data::Relocs_list::iterator & p)596 Sized_relobj_file<size, big_endian>::incremental_relocs_scan(
597     const Read_relocs_data::Relocs_list::iterator& p)
598 {
599   if (p->sh_type == elfcpp::SHT_REL)
600     this->incremental_relocs_scan_reltype<elfcpp::SHT_REL>(p);
601   else
602     {
603       gold_assert(p->sh_type == elfcpp::SHT_RELA);
604       this->incremental_relocs_scan_reltype<elfcpp::SHT_RELA>(p);
605     }
606 }
607 
608 // Scan the input relocation for --incremental, templatized on the
609 // type of the relocation section.
610 
611 template<int size, bool big_endian>
612 template<int sh_type>
613 void
incremental_relocs_scan_reltype(const Read_relocs_data::Relocs_list::iterator & p)614 Sized_relobj_file<size, big_endian>::incremental_relocs_scan_reltype(
615     const Read_relocs_data::Relocs_list::iterator& p)
616 {
617   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
618   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
619   const unsigned char* prelocs = p->contents->data();
620   size_t reloc_count = p->reloc_count;
621 
622   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
623     {
624       Reltype reloc(prelocs);
625 
626       if (p->needs_special_offset_handling
627 	  && !p->output_section->is_input_address_mapped(this, p->data_shndx,
628 						         reloc.get_r_offset()))
629 	continue;
630 
631       typename elfcpp::Elf_types<size>::Elf_WXword r_info =
632 	  reloc.get_r_info();
633       const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
634 
635       if (r_sym >= this->local_symbol_count_)
636 	this->count_incremental_reloc(r_sym - this->local_symbol_count_);
637     }
638 }
639 
640 // Relocate the input sections and write out the local symbols.
641 
642 template<int size, bool big_endian>
643 void
do_relocate(const Symbol_table * symtab,const Layout * layout,Output_file * of)644 Sized_relobj_file<size, big_endian>::do_relocate(const Symbol_table* symtab,
645 						 const Layout* layout,
646 						 Output_file* of)
647 {
648   unsigned int shnum = this->shnum();
649 
650   // Read the section headers.
651   const unsigned char* pshdrs = this->get_view(this->elf_file_.shoff(),
652 					       shnum * This::shdr_size,
653 					       true, true);
654 
655   Views views;
656   views.resize(shnum);
657 
658   // Make two passes over the sections.  The first one copies the
659   // section data to the output file.  The second one applies
660   // relocations.
661 
662   this->write_sections(layout, pshdrs, of, &views);
663 
664   // To speed up relocations, we set up hash tables for fast lookup of
665   // input offsets to output addresses.
666   this->initialize_input_to_output_maps();
667 
668   // Apply relocations.
669 
670   this->relocate_sections(symtab, layout, pshdrs, of, &views);
671 
672   // After we've done the relocations, we release the hash tables,
673   // since we no longer need them.
674   this->free_input_to_output_maps();
675 
676   // Write out the accumulated views.
677   for (unsigned int i = 1; i < shnum; ++i)
678     {
679       if (views[i].view != NULL)
680 	{
681 	  if (views[i].is_ctors_reverse_view)
682 	    this->reverse_words(views[i].view, views[i].view_size);
683 	  if (!views[i].is_postprocessing_view)
684 	    {
685 	      if (views[i].is_input_output_view)
686 		of->write_input_output_view(views[i].offset,
687 					    views[i].view_size,
688 					    views[i].view);
689 	      else
690 		of->write_output_view(views[i].offset, views[i].view_size,
691 				      views[i].view);
692 	    }
693 	}
694     }
695 
696   // Write out the local symbols.
697   this->write_local_symbols(of, layout->sympool(), layout->dynpool(),
698 			    layout->symtab_xindex(), layout->dynsym_xindex(),
699 			    layout->symtab_section_offset());
700 }
701 
702 // Sort a Read_multiple vector by file offset.
703 struct Read_multiple_compare
704 {
705   inline bool
operator ()gold::Read_multiple_compare706   operator()(const File_read::Read_multiple_entry& rme1,
707 	     const File_read::Read_multiple_entry& rme2) const
708   { return rme1.file_offset < rme2.file_offset; }
709 };
710 
711 // Write section data to the output file.  PSHDRS points to the
712 // section headers.  Record the views in *PVIEWS for use when
713 // relocating.
714 
715 template<int size, bool big_endian>
716 void
write_sections(const Layout * layout,const unsigned char * pshdrs,Output_file * of,Views * pviews)717 Sized_relobj_file<size, big_endian>::write_sections(const Layout* layout,
718 						    const unsigned char* pshdrs,
719 						    Output_file* of,
720 						    Views* pviews)
721 {
722   unsigned int shnum = this->shnum();
723   const Output_sections& out_sections(this->output_sections());
724   const std::vector<Address>& out_offsets(this->section_offsets());
725 
726   File_read::Read_multiple rm;
727   bool is_sorted = true;
728 
729   const unsigned char* p = pshdrs + This::shdr_size;
730   for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
731     {
732       View_size* pvs = &(*pviews)[i];
733 
734       pvs->view = NULL;
735 
736       const Output_section* os = out_sections[i];
737       if (os == NULL)
738 	continue;
739       Address output_offset = out_offsets[i];
740 
741       typename This::Shdr shdr(p);
742 
743       if (shdr.get_sh_type() == elfcpp::SHT_NOBITS)
744 	continue;
745 
746       if ((parameters->options().relocatable()
747 	   || parameters->options().emit_relocs())
748 	  && (shdr.get_sh_type() == elfcpp::SHT_REL
749 	      || shdr.get_sh_type() == elfcpp::SHT_RELA)
750 	  && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
751 	{
752 	  // This is a reloc section in a relocatable link or when
753 	  // emitting relocs.  We don't need to read the input file.
754 	  // The size and file offset are stored in the
755 	  // Relocatable_relocs structure.
756 	  Relocatable_relocs* rr = this->relocatable_relocs(i);
757 	  gold_assert(rr != NULL);
758 	  Output_data* posd = rr->output_data();
759 	  gold_assert(posd != NULL);
760 
761 	  pvs->offset = posd->offset();
762 	  pvs->view_size = posd->data_size();
763 	  pvs->view = of->get_output_view(pvs->offset, pvs->view_size);
764 	  pvs->address = posd->address();
765 	  pvs->is_input_output_view = false;
766 	  pvs->is_postprocessing_view = false;
767 	  pvs->is_ctors_reverse_view = false;
768 
769 	  continue;
770 	}
771 
772       // In the normal case, this input section is simply mapped to
773       // the output section at offset OUTPUT_OFFSET.
774 
775       // However, if OUTPUT_OFFSET == INVALID_ADDRESS, then input data is
776       // handled specially--e.g., a .eh_frame section.  The relocation
777       // routines need to check for each reloc where it should be
778       // applied.  For this case, we need an input/output view for the
779       // entire contents of the section in the output file.  We don't
780       // want to copy the contents of the input section to the output
781       // section; the output section contents were already written,
782       // and we waited for them in Relocate_task::is_runnable because
783       // relocs_must_follow_section_writes is set for the object.
784 
785       // Regardless of which of the above cases is true, we have to
786       // check requires_postprocessing of the output section.  If that
787       // is false, then we work with views of the output file
788       // directly.  If it is true, then we work with a separate
789       // buffer, and the output section is responsible for writing the
790       // final data to the output file.
791 
792       off_t output_section_offset;
793       Address output_section_size;
794       if (!os->requires_postprocessing())
795 	{
796 	  output_section_offset = os->offset();
797 	  output_section_size = convert_types<Address, off_t>(os->data_size());
798 	}
799       else
800 	{
801 	  output_section_offset = 0;
802 	  output_section_size =
803               convert_types<Address, off_t>(os->postprocessing_buffer_size());
804 	}
805 
806       off_t view_start;
807       section_size_type view_size;
808       bool must_decompress = false;
809       if (output_offset != invalid_address)
810 	{
811 	  view_start = output_section_offset + output_offset;
812 	  view_size = convert_to_section_size_type(shdr.get_sh_size());
813 	  section_size_type uncompressed_size;
814 	  if (this->section_is_compressed(i, &uncompressed_size))
815 	    {
816 	      view_size = uncompressed_size;
817 	      must_decompress = true;
818 	    }
819 	}
820       else
821 	{
822 	  view_start = output_section_offset;
823 	  view_size = convert_to_section_size_type(output_section_size);
824 	}
825 
826       if (view_size == 0)
827 	continue;
828 
829       gold_assert(output_offset == invalid_address
830 		  || output_offset + view_size <= output_section_size);
831 
832       unsigned char* view;
833       if (os->requires_postprocessing())
834 	{
835 	  unsigned char* buffer = os->postprocessing_buffer();
836 	  view = buffer + view_start;
837 	  if (output_offset != invalid_address && !must_decompress)
838 	    {
839 	      off_t sh_offset = shdr.get_sh_offset();
840 	      if (!rm.empty() && rm.back().file_offset > sh_offset)
841 		is_sorted = false;
842 	      rm.push_back(File_read::Read_multiple_entry(sh_offset,
843 							  view_size, view));
844 	    }
845 	}
846       else
847 	{
848 	  if (output_offset == invalid_address)
849 	    view = of->get_input_output_view(view_start, view_size);
850 	  else
851 	    {
852 	      view = of->get_output_view(view_start, view_size);
853 	      if (!must_decompress)
854 		{
855 		  off_t sh_offset = shdr.get_sh_offset();
856 		  if (!rm.empty() && rm.back().file_offset > sh_offset)
857 		    is_sorted = false;
858 		  rm.push_back(File_read::Read_multiple_entry(sh_offset,
859 							      view_size, view));
860 		}
861 	    }
862 	}
863 
864       if (must_decompress)
865         {
866 	  // Read and decompress the section.
867           section_size_type len;
868 	  const unsigned char* p = this->section_contents(i, &len, false);
869 	  if (!decompress_input_section(p, len, view, view_size))
870 	    this->error(_("could not decompress section %s"),
871 			this->section_name(i).c_str());
872         }
873 
874       pvs->view = view;
875       pvs->address = os->address();
876       if (output_offset != invalid_address)
877 	pvs->address += output_offset;
878       pvs->offset = view_start;
879       pvs->view_size = view_size;
880       pvs->is_input_output_view = output_offset == invalid_address;
881       pvs->is_postprocessing_view = os->requires_postprocessing();
882       pvs->is_ctors_reverse_view =
883 	(!parameters->options().relocatable()
884 	 && view_size > size / 8
885 	 && (strcmp(os->name(), ".init_array") == 0
886 	     || strcmp(os->name(), ".fini_array") == 0)
887 	 && layout->is_ctors_in_init_array(this, i));
888     }
889 
890   // Actually read the data.
891   if (!rm.empty())
892     {
893       if (!is_sorted)
894 	std::sort(rm.begin(), rm.end(), Read_multiple_compare());
895       this->read_multiple(rm);
896     }
897 }
898 
899 // Relocate section data.  VIEWS points to the section data as views
900 // in the output file.
901 
902 template<int size, bool big_endian>
903 void
do_relocate_sections(const Symbol_table * symtab,const Layout * layout,const unsigned char * pshdrs,Output_file * of,Views * pviews)904 Sized_relobj_file<size, big_endian>::do_relocate_sections(
905     const Symbol_table* symtab,
906     const Layout* layout,
907     const unsigned char* pshdrs,
908     Output_file* of,
909     Views* pviews)
910 {
911   unsigned int shnum = this->shnum();
912   Sized_target<size, big_endian>* target =
913     parameters->sized_target<size, big_endian>();
914 
915   const Output_sections& out_sections(this->output_sections());
916   const std::vector<Address>& out_offsets(this->section_offsets());
917 
918   Relocate_info<size, big_endian> relinfo;
919   relinfo.symtab = symtab;
920   relinfo.layout = layout;
921   relinfo.object = this;
922 
923   const unsigned char* p = pshdrs + This::shdr_size;
924   for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
925     {
926       typename This::Shdr shdr(p);
927 
928       unsigned int sh_type = shdr.get_sh_type();
929       if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
930 	continue;
931 
932       off_t sh_size = shdr.get_sh_size();
933       if (sh_size == 0)
934 	continue;
935 
936       unsigned int index = this->adjust_shndx(shdr.get_sh_info());
937       if (index >= this->shnum())
938 	{
939 	  this->error(_("relocation section %u has bad info %u"),
940 		      i, index);
941 	  continue;
942 	}
943 
944       Output_section* os = out_sections[index];
945       if (os == NULL)
946 	{
947 	  // This relocation section is against a section which we
948 	  // discarded.
949 	  continue;
950 	}
951       Address output_offset = out_offsets[index];
952 
953       gold_assert((*pviews)[index].view != NULL);
954       if (parameters->options().relocatable())
955 	gold_assert((*pviews)[i].view != NULL);
956 
957       if (this->adjust_shndx(shdr.get_sh_link()) != this->symtab_shndx_)
958 	{
959 	  gold_error(_("relocation section %u uses unexpected "
960 		       "symbol table %u"),
961 		     i, this->adjust_shndx(shdr.get_sh_link()));
962 	  continue;
963 	}
964 
965       const unsigned char* prelocs = this->get_view(shdr.get_sh_offset(),
966 						    sh_size, true, false);
967 
968       unsigned int reloc_size;
969       if (sh_type == elfcpp::SHT_REL)
970 	reloc_size = elfcpp::Elf_sizes<size>::rel_size;
971       else
972 	reloc_size = elfcpp::Elf_sizes<size>::rela_size;
973 
974       if (reloc_size != shdr.get_sh_entsize())
975 	{
976 	  gold_error(_("unexpected entsize for reloc section %u: %lu != %u"),
977 		     i, static_cast<unsigned long>(shdr.get_sh_entsize()),
978 		     reloc_size);
979 	  continue;
980 	}
981 
982       size_t reloc_count = sh_size / reloc_size;
983       if (static_cast<off_t>(reloc_count * reloc_size) != sh_size)
984 	{
985 	  gold_error(_("reloc section %u size %lu uneven"),
986 		     i, static_cast<unsigned long>(sh_size));
987 	  continue;
988 	}
989 
990       gold_assert(output_offset != invalid_address
991 		  || this->relocs_must_follow_section_writes());
992 
993       relinfo.reloc_shndx = i;
994       relinfo.reloc_shdr = p;
995       relinfo.data_shndx = index;
996       relinfo.data_shdr = pshdrs + index * This::shdr_size;
997       unsigned char* view = (*pviews)[index].view;
998       Address address = (*pviews)[index].address;
999       section_size_type view_size = (*pviews)[index].view_size;
1000 
1001       Reloc_symbol_changes* reloc_map = NULL;
1002       if (this->uses_split_stack() && output_offset != invalid_address)
1003 	{
1004 	  typename This::Shdr data_shdr(pshdrs + index * This::shdr_size);
1005 	  if ((data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
1006 	    this->split_stack_adjust(symtab, pshdrs, sh_type, index,
1007 				     prelocs, reloc_count, view, view_size,
1008 				     &reloc_map);
1009 	}
1010 
1011       if (!parameters->options().relocatable())
1012 	{
1013 	  target->relocate_section(&relinfo, sh_type, prelocs, reloc_count, os,
1014 				   output_offset == invalid_address,
1015 				   view, address, view_size, reloc_map);
1016 	  if (parameters->options().emit_relocs())
1017 	    {
1018 	      Relocatable_relocs* rr = this->relocatable_relocs(i);
1019 	      target->relocate_relocs(&relinfo, sh_type, prelocs, reloc_count,
1020 				      os, output_offset, rr,
1021 				      view, address, view_size,
1022 				      (*pviews)[i].view,
1023 				      (*pviews)[i].view_size);
1024 	    }
1025 	  if (parameters->incremental())
1026 	    this->incremental_relocs_write(&relinfo, sh_type, prelocs,
1027 					   reloc_count, os, output_offset, of);
1028 	}
1029       else
1030 	{
1031 	  Relocatable_relocs* rr = this->relocatable_relocs(i);
1032 	  target->relocate_relocs(&relinfo, sh_type, prelocs, reloc_count,
1033 				  os, output_offset, rr,
1034 				  view, address, view_size,
1035 				  (*pviews)[i].view,
1036 				  (*pviews)[i].view_size);
1037 	}
1038     }
1039 }
1040 
1041 // Write the incremental relocs.
1042 
1043 template<int size, bool big_endian>
1044 void
incremental_relocs_write(const Relocate_info<size,big_endian> * relinfo,unsigned int sh_type,const unsigned char * prelocs,size_t reloc_count,Output_section * output_section,Address output_offset,Output_file * of)1045 Sized_relobj_file<size, big_endian>::incremental_relocs_write(
1046     const Relocate_info<size, big_endian>* relinfo,
1047     unsigned int sh_type,
1048     const unsigned char* prelocs,
1049     size_t reloc_count,
1050     Output_section* output_section,
1051     Address output_offset,
1052     Output_file* of)
1053 {
1054   if (sh_type == elfcpp::SHT_REL)
1055     this->incremental_relocs_write_reltype<elfcpp::SHT_REL>(
1056 	relinfo,
1057 	prelocs,
1058 	reloc_count,
1059 	output_section,
1060 	output_offset,
1061 	of);
1062   else
1063     {
1064       gold_assert(sh_type == elfcpp::SHT_RELA);
1065       this->incremental_relocs_write_reltype<elfcpp::SHT_RELA>(
1066 	  relinfo,
1067 	  prelocs,
1068 	  reloc_count,
1069 	  output_section,
1070 	  output_offset,
1071 	  of);
1072     }
1073 }
1074 
1075 // Write the incremental relocs, templatized on the type of the
1076 // relocation section.
1077 
1078 template<int size, bool big_endian>
1079 template<int sh_type>
1080 void
incremental_relocs_write_reltype(const Relocate_info<size,big_endian> * relinfo,const unsigned char * prelocs,size_t reloc_count,Output_section * output_section,Address output_offset,Output_file * of)1081 Sized_relobj_file<size, big_endian>::incremental_relocs_write_reltype(
1082     const Relocate_info<size, big_endian>* relinfo,
1083     const unsigned char* prelocs,
1084     size_t reloc_count,
1085     Output_section* output_section,
1086     Address output_offset,
1087     Output_file* of)
1088 {
1089   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reloc;
1090   const unsigned int reloc_size =
1091       Reloc_types<sh_type, size, big_endian>::reloc_size;
1092   const unsigned int sizeof_addr = size / 8;
1093   const unsigned int incr_reloc_size =
1094       Incremental_relocs_reader<size, big_endian>::reloc_size;
1095 
1096   unsigned int out_shndx = output_section->out_shndx();
1097 
1098   // Get a view for the .gnu_incremental_relocs section.
1099 
1100   Incremental_inputs* inputs = relinfo->layout->incremental_inputs();
1101   gold_assert(inputs != NULL);
1102   const off_t relocs_off = inputs->relocs_section()->offset();
1103   const off_t relocs_size = inputs->relocs_section()->data_size();
1104   unsigned char* const view = of->get_output_view(relocs_off, relocs_size);
1105 
1106   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
1107     {
1108       Reloc reloc(prelocs);
1109 
1110       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
1111       const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
1112       const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
1113 
1114       if (r_sym < this->local_symbol_count_)
1115         continue;
1116 
1117       // Get the new offset--the location in the output section where
1118       // this relocation should be applied.
1119 
1120       Address offset = reloc.get_r_offset();
1121       if (output_offset != invalid_address)
1122 	offset += output_offset;
1123       else
1124 	{
1125           section_offset_type sot_offset =
1126               convert_types<section_offset_type, Address>(offset);
1127 	  section_offset_type new_sot_offset =
1128 	      output_section->output_offset(relinfo->object,
1129 					    relinfo->data_shndx,
1130 					    sot_offset);
1131 	  gold_assert(new_sot_offset != -1);
1132 	  offset += new_sot_offset;
1133 	}
1134 
1135       // Get the addend.
1136       typename elfcpp::Elf_types<size>::Elf_Swxword addend;
1137       if (sh_type == elfcpp::SHT_RELA)
1138 	addend =
1139 	    Reloc_types<sh_type, size, big_endian>::get_reloc_addend(&reloc);
1140       else
1141         {
1142           // FIXME: Get the addend for SHT_REL.
1143           addend = 0;
1144         }
1145 
1146       // Get the index of the output relocation.
1147 
1148       unsigned int reloc_index =
1149           this->next_incremental_reloc_index(r_sym - this->local_symbol_count_);
1150 
1151       // Write the relocation.
1152 
1153       unsigned char* pov = view + reloc_index * incr_reloc_size;
1154       elfcpp::Swap<32, big_endian>::writeval(pov, r_type);
1155       elfcpp::Swap<32, big_endian>::writeval(pov + 4, out_shndx);
1156       elfcpp::Swap<size, big_endian>::writeval(pov + 8, offset);
1157       elfcpp::Swap<size, big_endian>::writeval(pov + 8 + sizeof_addr, addend);
1158       of->write_output_view(pov - view, incr_reloc_size, view);
1159     }
1160 }
1161 
1162 // Create merge hash tables for the local symbols.  These are used to
1163 // speed up relocations.
1164 
1165 template<int size, bool big_endian>
1166 void
initialize_input_to_output_maps()1167 Sized_relobj_file<size, big_endian>::initialize_input_to_output_maps()
1168 {
1169   const unsigned int loccount = this->local_symbol_count_;
1170   for (unsigned int i = 1; i < loccount; ++i)
1171     {
1172       Symbol_value<size>& lv(this->local_values_[i]);
1173       lv.initialize_input_to_output_map(this);
1174     }
1175 }
1176 
1177 // Free merge hash tables for the local symbols.
1178 
1179 template<int size, bool big_endian>
1180 void
free_input_to_output_maps()1181 Sized_relobj_file<size, big_endian>::free_input_to_output_maps()
1182 {
1183   const unsigned int loccount = this->local_symbol_count_;
1184   for (unsigned int i = 1; i < loccount; ++i)
1185     {
1186       Symbol_value<size>& lv(this->local_values_[i]);
1187       lv.free_input_to_output_map();
1188     }
1189 }
1190 
1191 // If an object was compiled with -fsplit-stack, this is called to
1192 // check whether any relocations refer to functions defined in objects
1193 // which were not compiled with -fsplit-stack.  If they were, then we
1194 // need to apply some target-specific adjustments to request
1195 // additional stack space.
1196 
1197 template<int size, bool big_endian>
1198 void
split_stack_adjust(const Symbol_table * symtab,const unsigned char * pshdrs,unsigned int sh_type,unsigned int shndx,const unsigned char * prelocs,size_t reloc_count,unsigned char * view,section_size_type view_size,Reloc_symbol_changes ** reloc_map)1199 Sized_relobj_file<size, big_endian>::split_stack_adjust(
1200     const Symbol_table* symtab,
1201     const unsigned char* pshdrs,
1202     unsigned int sh_type,
1203     unsigned int shndx,
1204     const unsigned char* prelocs,
1205     size_t reloc_count,
1206     unsigned char* view,
1207     section_size_type view_size,
1208     Reloc_symbol_changes** reloc_map)
1209 {
1210   if (sh_type == elfcpp::SHT_REL)
1211     this->split_stack_adjust_reltype<elfcpp::SHT_REL>(symtab, pshdrs, shndx,
1212 						      prelocs, reloc_count,
1213 						      view, view_size,
1214 						      reloc_map);
1215   else
1216     {
1217       gold_assert(sh_type == elfcpp::SHT_RELA);
1218       this->split_stack_adjust_reltype<elfcpp::SHT_RELA>(symtab, pshdrs, shndx,
1219 							 prelocs, reloc_count,
1220 							 view, view_size,
1221 							 reloc_map);
1222     }
1223 }
1224 
1225 // Adjust for -fsplit-stack, templatized on the type of the relocation
1226 // section.
1227 
1228 template<int size, bool big_endian>
1229 template<int sh_type>
1230 void
split_stack_adjust_reltype(const Symbol_table * symtab,const unsigned char * pshdrs,unsigned int shndx,const unsigned char * prelocs,size_t reloc_count,unsigned char * view,section_size_type view_size,Reloc_symbol_changes ** reloc_map)1231 Sized_relobj_file<size, big_endian>::split_stack_adjust_reltype(
1232     const Symbol_table* symtab,
1233     const unsigned char* pshdrs,
1234     unsigned int shndx,
1235     const unsigned char* prelocs,
1236     size_t reloc_count,
1237     unsigned char* view,
1238     section_size_type view_size,
1239     Reloc_symbol_changes** reloc_map)
1240 {
1241   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
1242   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
1243 
1244   size_t local_count = this->local_symbol_count();
1245 
1246   std::vector<section_offset_type> non_split_refs;
1247 
1248   const unsigned char* pr = prelocs;
1249   for (size_t i = 0; i < reloc_count; ++i, pr += reloc_size)
1250     {
1251       Reltype reloc(pr);
1252 
1253       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
1254       unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
1255       if (r_sym < local_count)
1256 	continue;
1257 
1258       const Symbol* gsym = this->global_symbol(r_sym);
1259       gold_assert(gsym != NULL);
1260       if (gsym->is_forwarder())
1261 	gsym = symtab->resolve_forwards(gsym);
1262 
1263       // See if this relocation refers to a function defined in an
1264       // object compiled without -fsplit-stack.  Note that we don't
1265       // care about the type of relocation--this means that in some
1266       // cases we will ask for a large stack unnecessarily, but this
1267       // is not fatal.  FIXME: Some targets have symbols which are
1268       // functions but are not type STT_FUNC, e.g., STT_ARM_TFUNC.
1269       if (!gsym->is_undefined()
1270 	  && gsym->source() == Symbol::FROM_OBJECT
1271 	  && !gsym->object()->uses_split_stack())
1272 	{
1273 	  unsigned int r_type = elfcpp::elf_r_type<size>(reloc.get_r_info());
1274 	  if (parameters->target().is_call_to_non_split(gsym, r_type))
1275 	    {
1276 	      section_offset_type offset =
1277 		convert_to_section_size_type(reloc.get_r_offset());
1278 	      non_split_refs.push_back(offset);
1279 	    }
1280 	}
1281     }
1282 
1283   if (non_split_refs.empty())
1284     return;
1285 
1286   // At this point, every entry in NON_SPLIT_REFS indicates a
1287   // relocation which refers to a function in an object compiled
1288   // without -fsplit-stack.  We now have to convert that list into a
1289   // set of offsets to functions.  First, we find all the functions.
1290 
1291   Function_offsets function_offsets;
1292   this->find_functions(pshdrs, shndx, &function_offsets);
1293   if (function_offsets.empty())
1294     return;
1295 
1296   // Now get a list of the function with references to non split-stack
1297   // code.
1298 
1299   Function_offsets calls_non_split;
1300   for (std::vector<section_offset_type>::const_iterator p
1301 	 = non_split_refs.begin();
1302        p != non_split_refs.end();
1303        ++p)
1304     {
1305       Function_offsets::const_iterator low = function_offsets.lower_bound(*p);
1306       if (low == function_offsets.end())
1307 	--low;
1308       else if (low->first == *p)
1309 	;
1310       else if (low == function_offsets.begin())
1311 	continue;
1312       else
1313 	--low;
1314 
1315       calls_non_split.insert(*low);
1316     }
1317   if (calls_non_split.empty())
1318     return;
1319 
1320   // Now we have a set of functions to adjust.  The adjustments are
1321   // target specific.  Besides changing the output section view
1322   // however, it likes, the target may request a relocation change
1323   // from one global symbol name to another.
1324 
1325   for (Function_offsets::const_iterator p = calls_non_split.begin();
1326        p != calls_non_split.end();
1327        ++p)
1328     {
1329       std::string from;
1330       std::string to;
1331       parameters->target().calls_non_split(this, shndx, p->first, p->second,
1332 					   view, view_size, &from, &to);
1333       if (!from.empty())
1334 	{
1335 	  gold_assert(!to.empty());
1336 	  Symbol* tosym = NULL;
1337 
1338 	  // Find relocations in the relevant function which are for
1339 	  // FROM.
1340 	  pr = prelocs;
1341 	  for (size_t i = 0; i < reloc_count; ++i, pr += reloc_size)
1342 	    {
1343 	      Reltype reloc(pr);
1344 
1345 	      typename elfcpp::Elf_types<size>::Elf_WXword r_info =
1346 		reloc.get_r_info();
1347 	      unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
1348 	      if (r_sym < local_count)
1349 		continue;
1350 
1351 	      section_offset_type offset =
1352 		convert_to_section_size_type(reloc.get_r_offset());
1353 	      if (offset < p->first
1354 		  || (offset
1355 		      >= (p->first
1356 			  + static_cast<section_offset_type>(p->second))))
1357 		continue;
1358 
1359 	      const Symbol* gsym = this->global_symbol(r_sym);
1360 	      if (from == gsym->name())
1361 		{
1362 		  if (tosym == NULL)
1363 		    {
1364 		      tosym = symtab->lookup(to.c_str());
1365 		      if (tosym == NULL)
1366 			{
1367 			  this->error(_("could not convert call "
1368 					"to '%s' to '%s'"),
1369 				      from.c_str(), to.c_str());
1370 			  break;
1371 			}
1372 		    }
1373 
1374 		  if (*reloc_map == NULL)
1375 		    *reloc_map = new Reloc_symbol_changes(reloc_count);
1376 		  (*reloc_map)->set(i, tosym);
1377 		}
1378 	    }
1379 	}
1380     }
1381 }
1382 
1383 // Find all the function in this object defined in section SHNDX.
1384 // Store their offsets in the section in FUNCTION_OFFSETS.
1385 
1386 template<int size, bool big_endian>
1387 void
find_functions(const unsigned char * pshdrs,unsigned int shndx,Sized_relobj_file<size,big_endian>::Function_offsets * function_offsets)1388 Sized_relobj_file<size, big_endian>::find_functions(
1389     const unsigned char* pshdrs,
1390     unsigned int shndx,
1391     Sized_relobj_file<size, big_endian>::Function_offsets* function_offsets)
1392 {
1393   // We need to read the symbols to find the functions.  If we wanted
1394   // to, we could cache reading the symbols across all sections in the
1395   // object.
1396   const unsigned int symtab_shndx = this->symtab_shndx_;
1397   typename This::Shdr symtabshdr(pshdrs + symtab_shndx * This::shdr_size);
1398   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
1399 
1400   typename elfcpp::Elf_types<size>::Elf_WXword sh_size =
1401     symtabshdr.get_sh_size();
1402   const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
1403 					      sh_size, true, true);
1404 
1405   const int sym_size = This::sym_size;
1406   const unsigned int symcount = sh_size / sym_size;
1407   for (unsigned int i = 0; i < symcount; ++i, psyms += sym_size)
1408     {
1409       typename elfcpp::Sym<size, big_endian> isym(psyms);
1410 
1411       // FIXME: Some targets can have functions which do not have type
1412       // STT_FUNC, e.g., STT_ARM_TFUNC.
1413       if (isym.get_st_type() != elfcpp::STT_FUNC
1414 	  || isym.get_st_size() == 0)
1415 	continue;
1416 
1417       bool is_ordinary;
1418       unsigned int sym_shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
1419 						      &is_ordinary);
1420       if (!is_ordinary || sym_shndx != shndx)
1421 	continue;
1422 
1423       section_offset_type value =
1424 	convert_to_section_size_type(isym.get_st_value());
1425       section_size_type fnsize =
1426 	convert_to_section_size_type(isym.get_st_size());
1427 
1428       (*function_offsets)[value] = fnsize;
1429     }
1430 }
1431 
1432 // Reverse the words in a section.  Used for .ctors sections mapped to
1433 // .init_array sections.  See ctors_sections_in_init_array in
1434 // layout.cc.
1435 
1436 template<int size, bool big_endian>
1437 void
reverse_words(unsigned char * view,section_size_type view_size)1438 Sized_relobj_file<size, big_endian>::reverse_words(unsigned char* view,
1439 						   section_size_type view_size)
1440 {
1441   typedef typename elfcpp::Swap<size, big_endian>::Valtype Valtype;
1442   Valtype* vview = reinterpret_cast<Valtype*>(view);
1443   section_size_type vview_size = view_size / (size / 8);
1444   for (section_size_type i = 0; i < vview_size / 2; ++i)
1445     {
1446       Valtype tmp = vview[i];
1447       vview[i] = vview[vview_size - 1 - i];
1448       vview[vview_size - 1 - i] = tmp;
1449     }
1450 }
1451 
1452 // Class Merged_symbol_value.
1453 
1454 template<int size>
1455 void
initialize_input_to_output_map(const Relobj * object,unsigned int input_shndx)1456 Merged_symbol_value<size>::initialize_input_to_output_map(
1457     const Relobj* object,
1458     unsigned int input_shndx)
1459 {
1460   Object_merge_map* map = object->merge_map();
1461   map->initialize_input_to_output_map<size>(input_shndx,
1462 					    this->output_start_address_,
1463 					    &this->output_addresses_);
1464 }
1465 
1466 // Get the output value corresponding to an input offset if we
1467 // couldn't find it in the hash table.
1468 
1469 template<int size>
1470 typename elfcpp::Elf_types<size>::Elf_Addr
value_from_output_section(const Relobj * object,unsigned int input_shndx,typename elfcpp::Elf_types<size>::Elf_Addr input_offset) const1471 Merged_symbol_value<size>::value_from_output_section(
1472     const Relobj* object,
1473     unsigned int input_shndx,
1474     typename elfcpp::Elf_types<size>::Elf_Addr input_offset) const
1475 {
1476   section_offset_type output_offset;
1477   bool found = object->merge_map()->get_output_offset(NULL, input_shndx,
1478 						      input_offset,
1479 						      &output_offset);
1480 
1481   // If this assertion fails, it means that some relocation was
1482   // against a portion of an input merge section which we didn't map
1483   // to the output file and we didn't explicitly discard.  We should
1484   // always map all portions of input merge sections.
1485   gold_assert(found);
1486 
1487   if (output_offset == -1)
1488     return 0;
1489   else
1490     return this->output_start_address_ + output_offset;
1491 }
1492 
1493 // Track_relocs methods.
1494 
1495 // Initialize the class to track the relocs.  This gets the object,
1496 // the reloc section index, and the type of the relocs.  This returns
1497 // false if something goes wrong.
1498 
1499 template<int size, bool big_endian>
1500 bool
initialize(Object * object,unsigned int reloc_shndx,unsigned int reloc_type)1501 Track_relocs<size, big_endian>::initialize(
1502     Object* object,
1503     unsigned int reloc_shndx,
1504     unsigned int reloc_type)
1505 {
1506   // If RELOC_SHNDX is -1U, it means there is more than one reloc
1507   // section for the .eh_frame section.  We can't handle that case.
1508   if (reloc_shndx == -1U)
1509     return false;
1510 
1511   // If RELOC_SHNDX is 0, there is no reloc section.
1512   if (reloc_shndx == 0)
1513     return true;
1514 
1515   // Get the contents of the reloc section.
1516   this->prelocs_ = object->section_contents(reloc_shndx, &this->len_, false);
1517 
1518   if (reloc_type == elfcpp::SHT_REL)
1519     this->reloc_size_ = elfcpp::Elf_sizes<size>::rel_size;
1520   else if (reloc_type == elfcpp::SHT_RELA)
1521     this->reloc_size_ = elfcpp::Elf_sizes<size>::rela_size;
1522   else
1523     gold_unreachable();
1524 
1525   if (this->len_ % this->reloc_size_ != 0)
1526     {
1527       object->error(_("reloc section size %zu is not a multiple of "
1528 		      "reloc size %d\n"),
1529 		    static_cast<size_t>(this->len_),
1530 		    this->reloc_size_);
1531       return false;
1532     }
1533 
1534   return true;
1535 }
1536 
1537 // Return the offset of the next reloc, or -1 if there isn't one.
1538 
1539 template<int size, bool big_endian>
1540 off_t
next_offset() const1541 Track_relocs<size, big_endian>::next_offset() const
1542 {
1543   if (this->pos_ >= this->len_)
1544     return -1;
1545 
1546   // Rel and Rela start out the same, so we can always use Rel to find
1547   // the r_offset value.
1548   elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1549   return rel.get_r_offset();
1550 }
1551 
1552 // Return the index of the symbol referenced by the next reloc, or -1U
1553 // if there aren't any more relocs.
1554 
1555 template<int size, bool big_endian>
1556 unsigned int
next_symndx() const1557 Track_relocs<size, big_endian>::next_symndx() const
1558 {
1559   if (this->pos_ >= this->len_)
1560     return -1U;
1561 
1562   // Rel and Rela start out the same, so we can use Rel to find the
1563   // symbol index.
1564   elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1565   return elfcpp::elf_r_sym<size>(rel.get_r_info());
1566 }
1567 
1568 // Return the addend of the next reloc, or 0 if there isn't one.
1569 
1570 template<int size, bool big_endian>
1571 uint64_t
next_addend() const1572 Track_relocs<size, big_endian>::next_addend() const
1573 {
1574   if (this->pos_ >= this->len_)
1575     return 0;
1576   if (this->reloc_size_ == elfcpp::Elf_sizes<size>::rel_size)
1577     return 0;
1578   elfcpp::Rela<size, big_endian> rela(this->prelocs_ + this->pos_);
1579   return rela.get_r_addend();
1580 }
1581 
1582 // Advance to the next reloc whose r_offset is greater than or equal
1583 // to OFFSET.  Return the number of relocs we skip.
1584 
1585 template<int size, bool big_endian>
1586 int
advance(off_t offset)1587 Track_relocs<size, big_endian>::advance(off_t offset)
1588 {
1589   int ret = 0;
1590   while (this->pos_ < this->len_)
1591     {
1592       // Rel and Rela start out the same, so we can always use Rel to
1593       // find the r_offset value.
1594       elfcpp::Rel<size, big_endian> rel(this->prelocs_ + this->pos_);
1595       if (static_cast<off_t>(rel.get_r_offset()) >= offset)
1596 	break;
1597       ++ret;
1598       this->pos_ += this->reloc_size_;
1599     }
1600   return ret;
1601 }
1602 
1603 // Instantiate the templates we need.
1604 
1605 #ifdef HAVE_TARGET_32_LITTLE
1606 template
1607 void
1608 Sized_relobj_file<32, false>::do_read_relocs(Read_relocs_data* rd);
1609 #endif
1610 
1611 #ifdef HAVE_TARGET_32_BIG
1612 template
1613 void
1614 Sized_relobj_file<32, true>::do_read_relocs(Read_relocs_data* rd);
1615 #endif
1616 
1617 #ifdef HAVE_TARGET_64_LITTLE
1618 template
1619 void
1620 Sized_relobj_file<64, false>::do_read_relocs(Read_relocs_data* rd);
1621 #endif
1622 
1623 #ifdef HAVE_TARGET_64_BIG
1624 template
1625 void
1626 Sized_relobj_file<64, true>::do_read_relocs(Read_relocs_data* rd);
1627 #endif
1628 
1629 #ifdef HAVE_TARGET_32_LITTLE
1630 template
1631 void
1632 Sized_relobj_file<32, false>::do_gc_process_relocs(Symbol_table* symtab,
1633 						   Layout* layout,
1634 						   Read_relocs_data* rd);
1635 #endif
1636 
1637 #ifdef HAVE_TARGET_32_BIG
1638 template
1639 void
1640 Sized_relobj_file<32, true>::do_gc_process_relocs(Symbol_table* symtab,
1641 						  Layout* layout,
1642 						  Read_relocs_data* rd);
1643 #endif
1644 
1645 #ifdef HAVE_TARGET_64_LITTLE
1646 template
1647 void
1648 Sized_relobj_file<64, false>::do_gc_process_relocs(Symbol_table* symtab,
1649 						   Layout* layout,
1650 						   Read_relocs_data* rd);
1651 #endif
1652 
1653 #ifdef HAVE_TARGET_64_BIG
1654 template
1655 void
1656 Sized_relobj_file<64, true>::do_gc_process_relocs(Symbol_table* symtab,
1657 						  Layout* layout,
1658 						  Read_relocs_data* rd);
1659 #endif
1660 
1661 #ifdef HAVE_TARGET_32_LITTLE
1662 template
1663 void
1664 Sized_relobj_file<32, false>::do_scan_relocs(Symbol_table* symtab,
1665 					     Layout* layout,
1666 					     Read_relocs_data* rd);
1667 #endif
1668 
1669 #ifdef HAVE_TARGET_32_BIG
1670 template
1671 void
1672 Sized_relobj_file<32, true>::do_scan_relocs(Symbol_table* symtab,
1673 					    Layout* layout,
1674 					    Read_relocs_data* rd);
1675 #endif
1676 
1677 #ifdef HAVE_TARGET_64_LITTLE
1678 template
1679 void
1680 Sized_relobj_file<64, false>::do_scan_relocs(Symbol_table* symtab,
1681 					     Layout* layout,
1682 					     Read_relocs_data* rd);
1683 #endif
1684 
1685 #ifdef HAVE_TARGET_64_BIG
1686 template
1687 void
1688 Sized_relobj_file<64, true>::do_scan_relocs(Symbol_table* symtab,
1689 					    Layout* layout,
1690 					    Read_relocs_data* rd);
1691 #endif
1692 
1693 #ifdef HAVE_TARGET_32_LITTLE
1694 template
1695 void
1696 Sized_relobj_file<32, false>::do_relocate(const Symbol_table* symtab,
1697 					  const Layout* layout,
1698 					  Output_file* of);
1699 #endif
1700 
1701 #ifdef HAVE_TARGET_32_BIG
1702 template
1703 void
1704 Sized_relobj_file<32, true>::do_relocate(const Symbol_table* symtab,
1705 					 const Layout* layout,
1706 					 Output_file* of);
1707 #endif
1708 
1709 #ifdef HAVE_TARGET_64_LITTLE
1710 template
1711 void
1712 Sized_relobj_file<64, false>::do_relocate(const Symbol_table* symtab,
1713 					  const Layout* layout,
1714 					  Output_file* of);
1715 #endif
1716 
1717 #ifdef HAVE_TARGET_64_BIG
1718 template
1719 void
1720 Sized_relobj_file<64, true>::do_relocate(const Symbol_table* symtab,
1721 					 const Layout* layout,
1722 					 Output_file* of);
1723 #endif
1724 
1725 #ifdef HAVE_TARGET_32_LITTLE
1726 template
1727 void
1728 Sized_relobj_file<32, false>::do_relocate_sections(
1729     const Symbol_table* symtab,
1730     const Layout* layout,
1731     const unsigned char* pshdrs,
1732     Output_file* of,
1733     Views* pviews);
1734 #endif
1735 
1736 #ifdef HAVE_TARGET_32_BIG
1737 template
1738 void
1739 Sized_relobj_file<32, true>::do_relocate_sections(
1740     const Symbol_table* symtab,
1741     const Layout* layout,
1742     const unsigned char* pshdrs,
1743     Output_file* of,
1744     Views* pviews);
1745 #endif
1746 
1747 #ifdef HAVE_TARGET_64_LITTLE
1748 template
1749 void
1750 Sized_relobj_file<64, false>::do_relocate_sections(
1751     const Symbol_table* symtab,
1752     const Layout* layout,
1753     const unsigned char* pshdrs,
1754     Output_file* of,
1755     Views* pviews);
1756 #endif
1757 
1758 #ifdef HAVE_TARGET_64_BIG
1759 template
1760 void
1761 Sized_relobj_file<64, true>::do_relocate_sections(
1762     const Symbol_table* symtab,
1763     const Layout* layout,
1764     const unsigned char* pshdrs,
1765     Output_file* of,
1766     Views* pviews);
1767 #endif
1768 
1769 #ifdef HAVE_TARGET_32_LITTLE
1770 template
1771 void
1772 Sized_relobj_file<32, false>::initialize_input_to_output_maps();
1773 
1774 template
1775 void
1776 Sized_relobj_file<32, false>::free_input_to_output_maps();
1777 #endif
1778 
1779 #ifdef HAVE_TARGET_32_BIG
1780 template
1781 void
1782 Sized_relobj_file<32, true>::initialize_input_to_output_maps();
1783 
1784 template
1785 void
1786 Sized_relobj_file<32, true>::free_input_to_output_maps();
1787 #endif
1788 
1789 #ifdef HAVE_TARGET_64_LITTLE
1790 template
1791 void
1792 Sized_relobj_file<64, false>::initialize_input_to_output_maps();
1793 
1794 template
1795 void
1796 Sized_relobj_file<64, false>::free_input_to_output_maps();
1797 #endif
1798 
1799 #ifdef HAVE_TARGET_64_BIG
1800 template
1801 void
1802 Sized_relobj_file<64, true>::initialize_input_to_output_maps();
1803 
1804 template
1805 void
1806 Sized_relobj_file<64, true>::free_input_to_output_maps();
1807 #endif
1808 
1809 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1810 template
1811 class Merged_symbol_value<32>;
1812 #endif
1813 
1814 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1815 template
1816 class Merged_symbol_value<64>;
1817 #endif
1818 
1819 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1820 template
1821 class Symbol_value<32>;
1822 #endif
1823 
1824 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1825 template
1826 class Symbol_value<64>;
1827 #endif
1828 
1829 #ifdef HAVE_TARGET_32_LITTLE
1830 template
1831 class Track_relocs<32, false>;
1832 #endif
1833 
1834 #ifdef HAVE_TARGET_32_BIG
1835 template
1836 class Track_relocs<32, true>;
1837 #endif
1838 
1839 #ifdef HAVE_TARGET_64_LITTLE
1840 template
1841 class Track_relocs<64, false>;
1842 #endif
1843 
1844 #ifdef HAVE_TARGET_64_BIG
1845 template
1846 class Track_relocs<64, true>;
1847 #endif
1848 
1849 } // End namespace gold.
1850