1 // reloc.cc -- relocate input files for gold.
3 // Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
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.
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.
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.
27 #include "workqueue.h"
32 #include "target-reloc.h"
39 // Read_relocs methods.
41 // These tasks just read the relocation information from the file.
42 // After reading it, the start another task to process the
43 // information. These tasks requires access to the file.
46 Read_relocs::is_runnable()
48 return this->object_
->is_locked() ? this->object_
->token() : NULL
;
54 Read_relocs::locks(Task_locker
* tl
)
56 tl
->add(this, this->object_
->token());
59 // Read the relocations and then start a Scan_relocs_task.
62 Read_relocs::run(Workqueue
* workqueue
)
64 Read_relocs_data
*rd
= new Read_relocs_data
;
65 this->object_
->read_relocs(rd
);
66 this->object_
->set_relocs_data(rd
);
67 this->object_
->release();
69 // If garbage collection or identical comdat folding is desired, we
70 // process the relocs first before scanning them. Scanning of relocs is
71 // done only after garbage or identical sections is identified.
72 if (parameters
->options().gc_sections()
73 || parameters
->options().icf_enabled())
75 workqueue
->queue_next(new Gc_process_relocs(this->options_
,
84 workqueue
->queue_next(new Scan_relocs(this->options_
, this->symtab_
,
85 this->layout_
, this->object_
, rd
,
91 // Return a debugging name for the task.
94 Read_relocs::get_name() const
96 return "Read_relocs " + this->object_
->name();
99 // Gc_process_relocs methods.
101 // These tasks process the relocations read by Read_relocs and
102 // determine which sections are referenced and which are garbage.
103 // This task is done only when --gc-sections is used.
106 Gc_process_relocs::is_runnable()
108 if (this->object_
->is_locked())
109 return this->object_
->token();
114 Gc_process_relocs::locks(Task_locker
* tl
)
116 tl
->add(this, this->object_
->token());
117 tl
->add(this, this->blocker_
);
121 Gc_process_relocs::run(Workqueue
*)
123 this->object_
->gc_process_relocs(this->options_
, this->symtab_
, this->layout_
,
125 this->object_
->release();
128 // Return a debugging name for the task.
131 Gc_process_relocs::get_name() const
133 return "Gc_process_relocs " + this->object_
->name();
136 // Scan_relocs methods.
138 // These tasks scan the relocations read by Read_relocs and mark up
139 // the symbol table to indicate which relocations are required. We
140 // use a lock on the symbol table to keep them from interfering with
144 Scan_relocs::is_runnable()
146 if (!this->symtab_lock_
->is_writable())
147 return this->symtab_lock_
;
148 if (this->object_
->is_locked())
149 return this->object_
->token();
153 // Return the locks we hold: one on the file, one on the symbol table
157 Scan_relocs::locks(Task_locker
* tl
)
159 tl
->add(this, this->object_
->token());
160 tl
->add(this, this->symtab_lock_
);
161 tl
->add(this, this->blocker_
);
167 Scan_relocs::run(Workqueue
*)
169 this->object_
->scan_relocs(this->options_
, this->symtab_
, this->layout_
,
171 this->object_
->release();
176 // Return a debugging name for the task.
179 Scan_relocs::get_name() const
181 return "Scan_relocs " + this->object_
->name();
184 // Relocate_task methods.
186 // We may have to wait for the output sections to be written.
189 Relocate_task::is_runnable()
191 if (this->object_
->relocs_must_follow_section_writes()
192 && this->output_sections_blocker_
->is_blocked())
193 return this->output_sections_blocker_
;
195 if (this->object_
->is_locked())
196 return this->object_
->token();
201 // We want to lock the file while we run. We want to unblock
202 // INPUT_SECTIONS_BLOCKER and FINAL_BLOCKER when we are done.
203 // INPUT_SECTIONS_BLOCKER may be NULL.
206 Relocate_task::locks(Task_locker
* tl
)
208 if (this->input_sections_blocker_
!= NULL
)
209 tl
->add(this, this->input_sections_blocker_
);
210 tl
->add(this, this->final_blocker_
);
211 tl
->add(this, this->object_
->token());
217 Relocate_task::run(Workqueue
*)
219 this->object_
->relocate(this->options_
, this->symtab_
, this->layout_
,
222 // This is normally the last thing we will do with an object, so
223 // uncache all views.
224 this->object_
->clear_view_cache_marks();
226 this->object_
->release();
229 // Return a debugging name for the task.
232 Relocate_task::get_name() const
234 return "Relocate_task " + this->object_
->name();
237 // Read the relocs and local symbols from the object file and store
238 // the information in RD.
240 template<int size
, bool big_endian
>
242 Sized_relobj
<size
, big_endian
>::do_read_relocs(Read_relocs_data
* rd
)
246 unsigned int shnum
= this->shnum();
250 rd
->relocs
.reserve(shnum
/ 2);
252 const Output_sections
& out_sections(this->output_sections());
253 const std::vector
<Address
>& out_offsets(this->section_offsets_
);
255 const unsigned char *pshdrs
= this->get_view(this->elf_file_
.shoff(),
256 shnum
* This::shdr_size
,
258 // Skip the first, dummy, section.
259 const unsigned char *ps
= pshdrs
+ This::shdr_size
;
260 for (unsigned int i
= 1; i
< shnum
; ++i
, ps
+= This::shdr_size
)
262 typename
This::Shdr
shdr(ps
);
264 unsigned int sh_type
= shdr
.get_sh_type();
265 if (sh_type
!= elfcpp::SHT_REL
&& sh_type
!= elfcpp::SHT_RELA
)
268 unsigned int shndx
= this->adjust_shndx(shdr
.get_sh_info());
271 this->error(_("relocation section %u has bad info %u"),
276 Output_section
* os
= out_sections
[shndx
];
280 // We are scanning relocations in order to fill out the GOT and
281 // PLT sections. Relocations for sections which are not
282 // allocated (typically debugging sections) should not add new
283 // GOT and PLT entries. So we skip them unless this is a
284 // relocatable link or we need to emit relocations. FIXME: What
285 // should we do if a linker script maps a section with SHF_ALLOC
286 // clear to a section with SHF_ALLOC set?
287 typename
This::Shdr
secshdr(pshdrs
+ shndx
* This::shdr_size
);
288 bool is_section_allocated
= ((secshdr
.get_sh_flags() & elfcpp::SHF_ALLOC
)
290 if (!is_section_allocated
291 && !parameters
->options().relocatable()
292 && !parameters
->options().emit_relocs())
295 if (this->adjust_shndx(shdr
.get_sh_link()) != this->symtab_shndx_
)
297 this->error(_("relocation section %u uses unexpected "
299 i
, this->adjust_shndx(shdr
.get_sh_link()));
303 off_t sh_size
= shdr
.get_sh_size();
305 unsigned int reloc_size
;
306 if (sh_type
== elfcpp::SHT_REL
)
307 reloc_size
= elfcpp::Elf_sizes
<size
>::rel_size
;
309 reloc_size
= elfcpp::Elf_sizes
<size
>::rela_size
;
310 if (reloc_size
!= shdr
.get_sh_entsize())
312 this->error(_("unexpected entsize for reloc section %u: %lu != %u"),
313 i
, static_cast<unsigned long>(shdr
.get_sh_entsize()),
318 size_t reloc_count
= sh_size
/ reloc_size
;
319 if (static_cast<off_t
>(reloc_count
* reloc_size
) != sh_size
)
321 this->error(_("reloc section %u size %lu uneven"),
322 i
, static_cast<unsigned long>(sh_size
));
326 rd
->relocs
.push_back(Section_relocs());
327 Section_relocs
& sr(rd
->relocs
.back());
329 sr
.data_shndx
= shndx
;
330 sr
.contents
= this->get_lasting_view(shdr
.get_sh_offset(), sh_size
,
332 sr
.sh_type
= sh_type
;
333 sr
.reloc_count
= reloc_count
;
334 sr
.output_section
= os
;
335 sr
.needs_special_offset_handling
= out_offsets
[shndx
] == invalid_address
;
336 sr
.is_data_section_allocated
= is_section_allocated
;
339 // Read the local symbols.
340 gold_assert(this->symtab_shndx_
!= -1U);
341 if (this->symtab_shndx_
== 0 || this->local_symbol_count_
== 0)
342 rd
->local_symbols
= NULL
;
345 typename
This::Shdr
symtabshdr(pshdrs
346 + this->symtab_shndx_
* This::shdr_size
);
347 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
348 const int sym_size
= This::sym_size
;
349 const unsigned int loccount
= this->local_symbol_count_
;
350 gold_assert(loccount
== symtabshdr
.get_sh_info());
351 off_t locsize
= loccount
* sym_size
;
352 rd
->local_symbols
= this->get_lasting_view(symtabshdr
.get_sh_offset(),
353 locsize
, true, true);
357 // Process the relocs to generate mappings from source sections to referenced
358 // sections. This is used during garbage colletion to determine garbage
361 template<int size
, bool big_endian
>
363 Sized_relobj
<size
, big_endian
>::do_gc_process_relocs(const General_options
& options
,
364 Symbol_table
* symtab
,
366 Read_relocs_data
* rd
)
368 Sized_target
<size
, big_endian
>* target
=
369 parameters
->sized_target
<size
, big_endian
>();
371 const unsigned char* local_symbols
;
372 if (rd
->local_symbols
== NULL
)
373 local_symbols
= NULL
;
375 local_symbols
= rd
->local_symbols
->data();
377 for (Read_relocs_data::Relocs_list::iterator p
= rd
->relocs
.begin();
378 p
!= rd
->relocs
.end();
381 if (!parameters
->options().relocatable())
383 // As noted above, when not generating an object file, we
384 // only scan allocated sections. We may see a non-allocated
385 // section here if we are emitting relocs.
386 if (p
->is_data_section_allocated
)
387 target
->gc_process_relocs(options
, symtab
, layout
, this,
388 p
->data_shndx
, p
->sh_type
,
389 p
->contents
->data(), p
->reloc_count
,
391 p
->needs_special_offset_handling
,
392 this->local_symbol_count_
,
399 // Scan the relocs and adjust the symbol table. This looks for
400 // relocations which require GOT/PLT/COPY relocations.
402 template<int size
, bool big_endian
>
404 Sized_relobj
<size
, big_endian
>::do_scan_relocs(const General_options
& options
,
405 Symbol_table
* symtab
,
407 Read_relocs_data
* rd
)
409 Sized_target
<size
, big_endian
>* target
=
410 parameters
->sized_target
<size
, big_endian
>();
412 const unsigned char* local_symbols
;
413 if (rd
->local_symbols
== NULL
)
414 local_symbols
= NULL
;
416 local_symbols
= rd
->local_symbols
->data();
418 for (Read_relocs_data::Relocs_list::iterator p
= rd
->relocs
.begin();
419 p
!= rd
->relocs
.end();
422 // When garbage collection is on, unreferenced sections are not included
423 // in the link that would have been included normally. This is known only
424 // after Read_relocs hence this check has to be done again.
425 if (parameters
->options().gc_sections()
426 || parameters
->options().icf_enabled())
428 if (p
->output_section
== NULL
)
431 if (!parameters
->options().relocatable())
433 // As noted above, when not generating an object file, we
434 // only scan allocated sections. We may see a non-allocated
435 // section here if we are emitting relocs.
436 if (p
->is_data_section_allocated
)
437 target
->scan_relocs(options
, symtab
, layout
, this, p
->data_shndx
,
438 p
->sh_type
, p
->contents
->data(),
439 p
->reloc_count
, p
->output_section
,
440 p
->needs_special_offset_handling
,
441 this->local_symbol_count_
,
443 if (parameters
->options().emit_relocs())
444 this->emit_relocs_scan(options
, symtab
, layout
, local_symbols
, p
);
448 Relocatable_relocs
* rr
= this->relocatable_relocs(p
->reloc_shndx
);
449 gold_assert(rr
!= NULL
);
450 rr
->set_reloc_count(p
->reloc_count
);
451 target
->scan_relocatable_relocs(options
, symtab
, layout
, this,
452 p
->data_shndx
, p
->sh_type
,
456 p
->needs_special_offset_handling
,
457 this->local_symbol_count_
,
466 if (rd
->local_symbols
!= NULL
)
468 delete rd
->local_symbols
;
469 rd
->local_symbols
= NULL
;
473 // This is a strategy class we use when scanning for --emit-relocs.
475 template<int sh_type
>
476 class Emit_relocs_strategy
479 // A local non-section symbol.
480 inline Relocatable_relocs::Reloc_strategy
481 local_non_section_strategy(unsigned int, Relobj
*, unsigned int)
482 { return Relocatable_relocs::RELOC_COPY
; }
484 // A local section symbol.
485 inline Relocatable_relocs::Reloc_strategy
486 local_section_strategy(unsigned int, Relobj
*)
488 if (sh_type
== elfcpp::SHT_RELA
)
489 return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA
;
492 // The addend is stored in the section contents. Since this
493 // is not a relocatable link, we are going to apply the
494 // relocation contents to the section as usual. This means
495 // that we have no way to record the original addend. If the
496 // original addend is not zero, there is basically no way for
497 // the user to handle this correctly. Caveat emptor.
498 return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0
;
503 inline Relocatable_relocs::Reloc_strategy
504 global_strategy(unsigned int, Relobj
*, unsigned int)
505 { return Relocatable_relocs::RELOC_COPY
; }
508 // Scan the input relocations for --emit-relocs.
510 template<int size
, bool big_endian
>
512 Sized_relobj
<size
, big_endian
>::emit_relocs_scan(
513 const General_options
& options
,
514 Symbol_table
* symtab
,
516 const unsigned char* plocal_syms
,
517 const Read_relocs_data::Relocs_list::iterator
& p
)
519 Relocatable_relocs
* rr
= this->relocatable_relocs(p
->reloc_shndx
);
520 gold_assert(rr
!= NULL
);
521 rr
->set_reloc_count(p
->reloc_count
);
523 if (p
->sh_type
== elfcpp::SHT_REL
)
524 this->emit_relocs_scan_reltype
<elfcpp::SHT_REL
>(options
, symtab
, layout
,
528 gold_assert(p
->sh_type
== elfcpp::SHT_RELA
);
529 this->emit_relocs_scan_reltype
<elfcpp::SHT_RELA
>(options
, symtab
,
530 layout
, plocal_syms
, p
,
535 // Scan the input relocation for --emit-relocs, templatized on the
536 // type of the relocation section.
538 template<int size
, bool big_endian
>
539 template<int sh_type
>
541 Sized_relobj
<size
, big_endian
>::emit_relocs_scan_reltype(
542 const General_options
& options
,
543 Symbol_table
* symtab
,
545 const unsigned char* plocal_syms
,
546 const Read_relocs_data::Relocs_list::iterator
& p
,
547 Relocatable_relocs
* rr
)
549 scan_relocatable_relocs
<size
, big_endian
, sh_type
,
550 Emit_relocs_strategy
<sh_type
> >(
559 p
->needs_special_offset_handling
,
560 this->local_symbol_count_
,
565 // Relocate the input sections and write out the local symbols.
567 template<int size
, bool big_endian
>
569 Sized_relobj
<size
, big_endian
>::do_relocate(const General_options
& options
,
570 const Symbol_table
* symtab
,
571 const Layout
* layout
,
574 unsigned int shnum
= this->shnum();
576 // Read the section headers.
577 const unsigned char* pshdrs
= this->get_view(this->elf_file_
.shoff(),
578 shnum
* This::shdr_size
,
584 // Make two passes over the sections. The first one copies the
585 // section data to the output file. The second one applies
588 this->write_sections(pshdrs
, of
, &views
);
590 // To speed up relocations, we set up hash tables for fast lookup of
591 // input offsets to output addresses.
592 this->initialize_input_to_output_maps();
594 // Apply relocations.
596 this->relocate_sections(options
, symtab
, layout
, pshdrs
, &views
);
598 // After we've done the relocations, we release the hash tables,
599 // since we no longer need them.
600 this->free_input_to_output_maps();
602 // Write out the accumulated views.
603 for (unsigned int i
= 1; i
< shnum
; ++i
)
605 if (views
[i
].view
!= NULL
)
607 if (!views
[i
].is_postprocessing_view
)
609 if (views
[i
].is_input_output_view
)
610 of
->write_input_output_view(views
[i
].offset
,
614 of
->write_output_view(views
[i
].offset
, views
[i
].view_size
,
620 // Write out the local symbols.
621 this->write_local_symbols(of
, layout
->sympool(), layout
->dynpool(),
622 layout
->symtab_xindex(), layout
->dynsym_xindex());
624 // We should no longer need the local symbol values.
625 this->clear_local_symbols();
628 // Sort a Read_multiple vector by file offset.
629 struct Read_multiple_compare
632 operator()(const File_read::Read_multiple_entry
& rme1
,
633 const File_read::Read_multiple_entry
& rme2
) const
634 { return rme1
.file_offset
< rme2
.file_offset
; }
637 // Write section data to the output file. PSHDRS points to the
638 // section headers. Record the views in *PVIEWS for use when
641 template<int size
, bool big_endian
>
643 Sized_relobj
<size
, big_endian
>::write_sections(const unsigned char* pshdrs
,
647 unsigned int shnum
= this->shnum();
648 const Output_sections
& out_sections(this->output_sections());
649 const std::vector
<Address
>& out_offsets(this->section_offsets_
);
651 File_read::Read_multiple rm
;
652 bool is_sorted
= true;
654 const unsigned char* p
= pshdrs
+ This::shdr_size
;
655 for (unsigned int i
= 1; i
< shnum
; ++i
, p
+= This::shdr_size
)
657 View_size
* pvs
= &(*pviews
)[i
];
661 const Output_section
* os
= out_sections
[i
];
664 Address output_offset
= out_offsets
[i
];
666 typename
This::Shdr
shdr(p
);
668 if (shdr
.get_sh_type() == elfcpp::SHT_NOBITS
)
671 if ((parameters
->options().relocatable()
672 || parameters
->options().emit_relocs())
673 && (shdr
.get_sh_type() == elfcpp::SHT_REL
674 || shdr
.get_sh_type() == elfcpp::SHT_RELA
)
675 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
677 // This is a reloc section in a relocatable link or when
678 // emitting relocs. We don't need to read the input file.
679 // The size and file offset are stored in the
680 // Relocatable_relocs structure.
681 Relocatable_relocs
* rr
= this->relocatable_relocs(i
);
682 gold_assert(rr
!= NULL
);
683 Output_data
* posd
= rr
->output_data();
684 gold_assert(posd
!= NULL
);
686 pvs
->offset
= posd
->offset();
687 pvs
->view_size
= posd
->data_size();
688 pvs
->view
= of
->get_output_view(pvs
->offset
, pvs
->view_size
);
689 pvs
->address
= posd
->address();
690 pvs
->is_input_output_view
= false;
691 pvs
->is_postprocessing_view
= false;
696 // In the normal case, this input section is simply mapped to
697 // the output section at offset OUTPUT_OFFSET.
699 // However, if OUTPUT_OFFSET == INVALID_ADDRESS, then input data is
700 // handled specially--e.g., a .eh_frame section. The relocation
701 // routines need to check for each reloc where it should be
702 // applied. For this case, we need an input/output view for the
703 // entire contents of the section in the output file. We don't
704 // want to copy the contents of the input section to the output
705 // section; the output section contents were already written,
706 // and we waited for them in Relocate_task::is_runnable because
707 // relocs_must_follow_section_writes is set for the object.
709 // Regardless of which of the above cases is true, we have to
710 // check requires_postprocessing of the output section. If that
711 // is false, then we work with views of the output file
712 // directly. If it is true, then we work with a separate
713 // buffer, and the output section is responsible for writing the
714 // final data to the output file.
716 off_t output_section_offset
;
717 Address output_section_size
;
718 if (!os
->requires_postprocessing())
720 output_section_offset
= os
->offset();
721 output_section_size
= convert_types
<Address
, off_t
>(os
->data_size());
725 output_section_offset
= 0;
726 output_section_size
=
727 convert_types
<Address
, off_t
>(os
->postprocessing_buffer_size());
731 section_size_type view_size
;
732 if (output_offset
!= invalid_address
)
734 view_start
= output_section_offset
+ output_offset
;
735 view_size
= convert_to_section_size_type(shdr
.get_sh_size());
739 view_start
= output_section_offset
;
740 view_size
= convert_to_section_size_type(output_section_size
);
746 gold_assert(output_offset
== invalid_address
747 || output_offset
+ view_size
<= output_section_size
);
750 if (os
->requires_postprocessing())
752 unsigned char* buffer
= os
->postprocessing_buffer();
753 view
= buffer
+ view_start
;
754 if (output_offset
!= invalid_address
)
756 off_t sh_offset
= shdr
.get_sh_offset();
757 if (!rm
.empty() && rm
.back().file_offset
> sh_offset
)
759 rm
.push_back(File_read::Read_multiple_entry(sh_offset
,
765 if (output_offset
== invalid_address
)
766 view
= of
->get_input_output_view(view_start
, view_size
);
769 view
= of
->get_output_view(view_start
, view_size
);
770 off_t sh_offset
= shdr
.get_sh_offset();
771 if (!rm
.empty() && rm
.back().file_offset
> sh_offset
)
773 rm
.push_back(File_read::Read_multiple_entry(sh_offset
,
779 pvs
->address
= os
->address();
780 if (output_offset
!= invalid_address
)
781 pvs
->address
+= output_offset
;
782 pvs
->offset
= view_start
;
783 pvs
->view_size
= view_size
;
784 pvs
->is_input_output_view
= output_offset
== invalid_address
;
785 pvs
->is_postprocessing_view
= os
->requires_postprocessing();
788 // Actually read the data.
792 std::sort(rm
.begin(), rm
.end(), Read_multiple_compare());
793 this->read_multiple(rm
);
797 // Relocate section data. VIEWS points to the section data as views
798 // in the output file.
800 template<int size
, bool big_endian
>
802 Sized_relobj
<size
, big_endian
>::do_relocate_sections(
803 const General_options
& options
,
804 const Symbol_table
* symtab
,
805 const Layout
* layout
,
806 const unsigned char* pshdrs
,
809 unsigned int shnum
= this->shnum();
810 Sized_target
<size
, big_endian
>* target
=
811 parameters
->sized_target
<size
, big_endian
>();
813 const Output_sections
& out_sections(this->output_sections());
814 const std::vector
<Address
>& out_offsets(this->section_offsets_
);
816 Relocate_info
<size
, big_endian
> relinfo
;
817 relinfo
.options
= &options
;
818 relinfo
.symtab
= symtab
;
819 relinfo
.layout
= layout
;
820 relinfo
.object
= this;
822 const unsigned char* p
= pshdrs
+ This::shdr_size
;
823 for (unsigned int i
= 1; i
< shnum
; ++i
, p
+= This::shdr_size
)
825 typename
This::Shdr
shdr(p
);
827 unsigned int sh_type
= shdr
.get_sh_type();
828 if (sh_type
!= elfcpp::SHT_REL
&& sh_type
!= elfcpp::SHT_RELA
)
831 off_t sh_size
= shdr
.get_sh_size();
835 unsigned int index
= this->adjust_shndx(shdr
.get_sh_info());
836 if (index
>= this->shnum())
838 this->error(_("relocation section %u has bad info %u"),
843 Output_section
* os
= out_sections
[index
];
846 // This relocation section is against a section which we
850 Address output_offset
= out_offsets
[index
];
852 gold_assert((*pviews
)[index
].view
!= NULL
);
853 if (parameters
->options().relocatable())
854 gold_assert((*pviews
)[i
].view
!= NULL
);
856 if (this->adjust_shndx(shdr
.get_sh_link()) != this->symtab_shndx_
)
858 gold_error(_("relocation section %u uses unexpected "
860 i
, this->adjust_shndx(shdr
.get_sh_link()));
864 const unsigned char* prelocs
= this->get_view(shdr
.get_sh_offset(),
865 sh_size
, true, false);
867 unsigned int reloc_size
;
868 if (sh_type
== elfcpp::SHT_REL
)
869 reloc_size
= elfcpp::Elf_sizes
<size
>::rel_size
;
871 reloc_size
= elfcpp::Elf_sizes
<size
>::rela_size
;
873 if (reloc_size
!= shdr
.get_sh_entsize())
875 gold_error(_("unexpected entsize for reloc section %u: %lu != %u"),
876 i
, static_cast<unsigned long>(shdr
.get_sh_entsize()),
881 size_t reloc_count
= sh_size
/ reloc_size
;
882 if (static_cast<off_t
>(reloc_count
* reloc_size
) != sh_size
)
884 gold_error(_("reloc section %u size %lu uneven"),
885 i
, static_cast<unsigned long>(sh_size
));
889 gold_assert(output_offset
!= invalid_address
890 || this->relocs_must_follow_section_writes());
892 relinfo
.reloc_shndx
= i
;
893 relinfo
.reloc_shdr
= p
;
894 relinfo
.data_shndx
= index
;
895 relinfo
.data_shdr
= pshdrs
+ index
* This::shdr_size
;
896 unsigned char* view
= (*pviews
)[index
].view
;
897 Address address
= (*pviews
)[index
].address
;
898 section_size_type view_size
= (*pviews
)[index
].view_size
;
900 Reloc_symbol_changes
* reloc_map
= NULL
;
901 if (this->uses_split_stack() && output_offset
!= invalid_address
)
903 typename
This::Shdr
data_shdr(pshdrs
+ index
* This::shdr_size
);
904 if ((data_shdr
.get_sh_flags() & elfcpp::SHF_EXECINSTR
) != 0)
905 this->split_stack_adjust(symtab
, pshdrs
, sh_type
, index
,
906 prelocs
, reloc_count
, view
, view_size
,
910 if (!parameters
->options().relocatable())
912 target
->relocate_section(&relinfo
, sh_type
, prelocs
, reloc_count
, os
,
913 output_offset
== invalid_address
,
914 view
, address
, view_size
, reloc_map
);
915 if (parameters
->options().emit_relocs())
916 this->emit_relocs(&relinfo
, i
, sh_type
, prelocs
, reloc_count
,
917 os
, output_offset
, view
, address
, view_size
,
918 (*pviews
)[i
].view
, (*pviews
)[i
].view_size
);
922 Relocatable_relocs
* rr
= this->relocatable_relocs(i
);
923 target
->relocate_for_relocatable(&relinfo
, sh_type
, prelocs
,
924 reloc_count
, os
, output_offset
, rr
,
925 view
, address
, view_size
,
927 (*pviews
)[i
].view_size
);
932 // Emit the relocs for --emit-relocs.
934 template<int size
, bool big_endian
>
936 Sized_relobj
<size
, big_endian
>::emit_relocs(
937 const Relocate_info
<size
, big_endian
>* relinfo
,
939 unsigned int sh_type
,
940 const unsigned char* prelocs
,
942 Output_section
* output_section
,
943 typename
elfcpp::Elf_types
<size
>::Elf_Addr offset_in_output_section
,
945 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
,
946 section_size_type view_size
,
947 unsigned char* reloc_view
,
948 section_size_type reloc_view_size
)
950 if (sh_type
== elfcpp::SHT_REL
)
951 this->emit_relocs_reltype
<elfcpp::SHT_REL
>(relinfo
, i
, prelocs
,
952 reloc_count
, output_section
,
953 offset_in_output_section
,
954 view
, address
, view_size
,
955 reloc_view
, reloc_view_size
);
958 gold_assert(sh_type
== elfcpp::SHT_RELA
);
959 this->emit_relocs_reltype
<elfcpp::SHT_RELA
>(relinfo
, i
, prelocs
,
960 reloc_count
, output_section
,
961 offset_in_output_section
,
962 view
, address
, view_size
,
963 reloc_view
, reloc_view_size
);
967 // Emit the relocs for --emit-relocs, templatized on the type of the
968 // relocation section.
970 template<int size
, bool big_endian
>
971 template<int sh_type
>
973 Sized_relobj
<size
, big_endian
>::emit_relocs_reltype(
974 const Relocate_info
<size
, big_endian
>* relinfo
,
976 const unsigned char* prelocs
,
978 Output_section
* output_section
,
979 typename
elfcpp::Elf_types
<size
>::Elf_Addr offset_in_output_section
,
981 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
,
982 section_size_type view_size
,
983 unsigned char* reloc_view
,
984 section_size_type reloc_view_size
)
986 const Relocatable_relocs
* rr
= this->relocatable_relocs(i
);
987 relocate_for_relocatable
<size
, big_endian
, sh_type
>(
992 offset_in_output_section
,
1001 // Create merge hash tables for the local symbols. These are used to
1002 // speed up relocations.
1004 template<int size
, bool big_endian
>
1006 Sized_relobj
<size
, big_endian
>::initialize_input_to_output_maps()
1008 const unsigned int loccount
= this->local_symbol_count_
;
1009 for (unsigned int i
= 1; i
< loccount
; ++i
)
1011 Symbol_value
<size
>& lv(this->local_values_
[i
]);
1012 lv
.initialize_input_to_output_map(this);
1016 // Free merge hash tables for the local symbols.
1018 template<int size
, bool big_endian
>
1020 Sized_relobj
<size
, big_endian
>::free_input_to_output_maps()
1022 const unsigned int loccount
= this->local_symbol_count_
;
1023 for (unsigned int i
= 1; i
< loccount
; ++i
)
1025 Symbol_value
<size
>& lv(this->local_values_
[i
]);
1026 lv
.free_input_to_output_map();
1030 // If an object was compiled with -fsplit-stack, this is called to
1031 // check whether any relocations refer to functions defined in objects
1032 // which were not compiled with -fsplit-stack. If they were, then we
1033 // need to apply some target-specific adjustments to request
1034 // additional stack space.
1036 template<int size
, bool big_endian
>
1038 Sized_relobj
<size
, big_endian
>::split_stack_adjust(
1039 const Symbol_table
* symtab
,
1040 const unsigned char* pshdrs
,
1041 unsigned int sh_type
,
1043 const unsigned char* prelocs
,
1045 unsigned char* view
,
1046 section_size_type view_size
,
1047 Reloc_symbol_changes
** reloc_map
)
1049 if (sh_type
== elfcpp::SHT_REL
)
1050 this->split_stack_adjust_reltype
<elfcpp::SHT_REL
>(symtab
, pshdrs
, shndx
,
1051 prelocs
, reloc_count
,
1056 gold_assert(sh_type
== elfcpp::SHT_RELA
);
1057 this->split_stack_adjust_reltype
<elfcpp::SHT_RELA
>(symtab
, pshdrs
, shndx
,
1058 prelocs
, reloc_count
,
1064 // Adjust for -fsplit-stack, templatized on the type of the relocation
1067 template<int size
, bool big_endian
>
1068 template<int sh_type
>
1070 Sized_relobj
<size
, big_endian
>::split_stack_adjust_reltype(
1071 const Symbol_table
* symtab
,
1072 const unsigned char* pshdrs
,
1074 const unsigned char* prelocs
,
1076 unsigned char* view
,
1077 section_size_type view_size
,
1078 Reloc_symbol_changes
** reloc_map
)
1080 typedef typename Reloc_types
<sh_type
, size
, big_endian
>::Reloc Reltype
;
1081 const int reloc_size
= Reloc_types
<sh_type
, size
, big_endian
>::reloc_size
;
1083 size_t local_count
= this->local_symbol_count();
1085 std::vector
<section_offset_type
> non_split_refs
;
1087 const unsigned char* pr
= prelocs
;
1088 for (size_t i
= 0; i
< reloc_count
; ++i
, pr
+= reloc_size
)
1092 typename
elfcpp::Elf_types
<size
>::Elf_WXword r_info
= reloc
.get_r_info();
1093 unsigned int r_sym
= elfcpp::elf_r_sym
<size
>(r_info
);
1094 if (r_sym
< local_count
)
1097 const Symbol
* gsym
= this->global_symbol(r_sym
);
1098 gold_assert(gsym
!= NULL
);
1099 if (gsym
->is_forwarder())
1100 gsym
= symtab
->resolve_forwards(gsym
);
1102 // See if this relocation refers to a function defined in an
1103 // object compiled without -fsplit-stack. Note that we don't
1104 // care about the type of relocation--this means that in some
1105 // cases we will ask for a large stack unnecessarily, but this
1106 // is not fatal. FIXME: Some targets have symbols which are
1107 // functions but are not type STT_FUNC, e.g., STT_ARM_TFUNC.
1108 if (gsym
->type() == elfcpp::STT_FUNC
1109 && !gsym
->is_undefined()
1110 && gsym
->source() == Symbol::FROM_OBJECT
1111 && !gsym
->object()->uses_split_stack())
1113 section_offset_type offset
=
1114 convert_to_section_size_type(reloc
.get_r_offset());
1115 non_split_refs
.push_back(offset
);
1119 if (non_split_refs
.empty())
1122 // At this point, every entry in NON_SPLIT_REFS indicates a
1123 // relocation which refers to a function in an object compiled
1124 // without -fsplit-stack. We now have to convert that list into a
1125 // set of offsets to functions. First, we find all the functions.
1127 Function_offsets function_offsets
;
1128 this->find_functions(pshdrs
, shndx
, &function_offsets
);
1129 if (function_offsets
.empty())
1132 // Now get a list of the function with references to non split-stack
1135 Function_offsets calls_non_split
;
1136 for (std::vector
<section_offset_type
>::const_iterator p
1137 = non_split_refs
.begin();
1138 p
!= non_split_refs
.end();
1141 Function_offsets::const_iterator low
= function_offsets
.lower_bound(*p
);
1142 if (low
== function_offsets
.end())
1144 else if (low
->first
== *p
)
1146 else if (low
== function_offsets
.begin())
1151 calls_non_split
.insert(*low
);
1153 if (calls_non_split
.empty())
1156 // Now we have a set of functions to adjust. The adjustments are
1157 // target specific. Besides changing the output section view
1158 // however, it likes, the target may request a relocation change
1159 // from one global symbol name to another.
1161 for (Function_offsets::const_iterator p
= calls_non_split
.begin();
1162 p
!= calls_non_split
.end();
1167 parameters
->target().calls_non_split(this, shndx
, p
->first
, p
->second
,
1168 view
, view_size
, &from
, &to
);
1171 gold_assert(!to
.empty());
1172 Symbol
* tosym
= NULL
;
1174 // Find relocations in the relevant function which are for
1177 for (size_t i
= 0; i
< reloc_count
; ++i
, pr
+= reloc_size
)
1181 typename
elfcpp::Elf_types
<size
>::Elf_WXword r_info
=
1183 unsigned int r_sym
= elfcpp::elf_r_sym
<size
>(r_info
);
1184 if (r_sym
< local_count
)
1187 section_offset_type offset
=
1188 convert_to_section_size_type(reloc
.get_r_offset());
1189 if (offset
< p
->first
1192 + static_cast<section_offset_type
>(p
->second
))))
1195 const Symbol
* gsym
= this->global_symbol(r_sym
);
1196 if (from
== gsym
->name())
1200 tosym
= symtab
->lookup(to
.c_str());
1203 this->error(_("could not convert call "
1205 from
.c_str(), to
.c_str());
1210 if (*reloc_map
== NULL
)
1211 *reloc_map
= new Reloc_symbol_changes(reloc_count
);
1212 (*reloc_map
)->set(i
, tosym
);
1219 // Find all the function in this object defined in section SHNDX.
1220 // Store their offsets in the section in FUNCTION_OFFSETS.
1222 template<int size
, bool big_endian
>
1224 Sized_relobj
<size
, big_endian
>::find_functions(
1225 const unsigned char* pshdrs
,
1227 Sized_relobj
<size
, big_endian
>::Function_offsets
* function_offsets
)
1229 // We need to read the symbols to find the functions. If we wanted
1230 // to, we could cache reading the symbols across all sections in the
1232 const unsigned int symtab_shndx
= this->symtab_shndx_
;
1233 typename
This::Shdr
symtabshdr(pshdrs
+ symtab_shndx
* This::shdr_size
);
1234 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
1236 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_size
=
1237 symtabshdr
.get_sh_size();
1238 const unsigned char* psyms
= this->get_view(symtabshdr
.get_sh_offset(),
1239 sh_size
, true, true);
1241 const int sym_size
= This::sym_size
;
1242 const unsigned int symcount
= sh_size
/ sym_size
;
1243 for (unsigned int i
= 0; i
< symcount
; ++i
, psyms
+= sym_size
)
1245 typename
elfcpp::Sym
<size
, big_endian
> isym(psyms
);
1247 // FIXME: Some targets can have functions which do not have type
1248 // STT_FUNC, e.g., STT_ARM_TFUNC.
1249 if (isym
.get_st_type() != elfcpp::STT_FUNC
1250 || isym
.get_st_size() == 0)
1254 unsigned int sym_shndx
= this->adjust_sym_shndx(i
, isym
.get_st_shndx(),
1256 if (!is_ordinary
|| sym_shndx
!= shndx
)
1259 section_offset_type value
=
1260 convert_to_section_size_type(isym
.get_st_value());
1261 section_size_type fnsize
=
1262 convert_to_section_size_type(isym
.get_st_size());
1264 (*function_offsets
)[value
] = fnsize
;
1268 // Class Merged_symbol_value.
1272 Merged_symbol_value
<size
>::initialize_input_to_output_map(
1273 const Relobj
* object
,
1274 unsigned int input_shndx
)
1276 Object_merge_map
* map
= object
->merge_map();
1277 map
->initialize_input_to_output_map
<size
>(input_shndx
,
1278 this->output_start_address_
,
1279 &this->output_addresses_
);
1282 // Get the output value corresponding to an input offset if we
1283 // couldn't find it in the hash table.
1286 typename
elfcpp::Elf_types
<size
>::Elf_Addr
1287 Merged_symbol_value
<size
>::value_from_output_section(
1288 const Relobj
* object
,
1289 unsigned int input_shndx
,
1290 typename
elfcpp::Elf_types
<size
>::Elf_Addr input_offset
) const
1292 section_offset_type output_offset
;
1293 bool found
= object
->merge_map()->get_output_offset(NULL
, input_shndx
,
1297 // If this assertion fails, it means that some relocation was
1298 // against a portion of an input merge section which we didn't map
1299 // to the output file and we didn't explicitly discard. We should
1300 // always map all portions of input merge sections.
1303 if (output_offset
== -1)
1306 return this->output_start_address_
+ output_offset
;
1309 // Track_relocs methods.
1311 // Initialize the class to track the relocs. This gets the object,
1312 // the reloc section index, and the type of the relocs. This returns
1313 // false if something goes wrong.
1315 template<int size
, bool big_endian
>
1317 Track_relocs
<size
, big_endian
>::initialize(
1319 unsigned int reloc_shndx
,
1320 unsigned int reloc_type
)
1322 // If RELOC_SHNDX is -1U, it means there is more than one reloc
1323 // section for the .eh_frame section. We can't handle that case.
1324 if (reloc_shndx
== -1U)
1327 // If RELOC_SHNDX is 0, there is no reloc section.
1328 if (reloc_shndx
== 0)
1331 // Get the contents of the reloc section.
1332 this->prelocs_
= object
->section_contents(reloc_shndx
, &this->len_
, false);
1334 if (reloc_type
== elfcpp::SHT_REL
)
1335 this->reloc_size_
= elfcpp::Elf_sizes
<size
>::rel_size
;
1336 else if (reloc_type
== elfcpp::SHT_RELA
)
1337 this->reloc_size_
= elfcpp::Elf_sizes
<size
>::rela_size
;
1341 if (this->len_
% this->reloc_size_
!= 0)
1343 object
->error(_("reloc section size %zu is not a multiple of "
1345 static_cast<size_t>(this->len_
),
1353 // Return the offset of the next reloc, or -1 if there isn't one.
1355 template<int size
, bool big_endian
>
1357 Track_relocs
<size
, big_endian
>::next_offset() const
1359 if (this->pos_
>= this->len_
)
1362 // Rel and Rela start out the same, so we can always use Rel to find
1363 // the r_offset value.
1364 elfcpp::Rel
<size
, big_endian
> rel(this->prelocs_
+ this->pos_
);
1365 return rel
.get_r_offset();
1368 // Return the index of the symbol referenced by the next reloc, or -1U
1369 // if there aren't any more relocs.
1371 template<int size
, bool big_endian
>
1373 Track_relocs
<size
, big_endian
>::next_symndx() const
1375 if (this->pos_
>= this->len_
)
1378 // Rel and Rela start out the same, so we can use Rel to find the
1380 elfcpp::Rel
<size
, big_endian
> rel(this->prelocs_
+ this->pos_
);
1381 return elfcpp::elf_r_sym
<size
>(rel
.get_r_info());
1384 // Advance to the next reloc whose r_offset is greater than or equal
1385 // to OFFSET. Return the number of relocs we skip.
1387 template<int size
, bool big_endian
>
1389 Track_relocs
<size
, big_endian
>::advance(off_t offset
)
1392 while (this->pos_
< this->len_
)
1394 // Rel and Rela start out the same, so we can always use Rel to
1395 // find the r_offset value.
1396 elfcpp::Rel
<size
, big_endian
> rel(this->prelocs_
+ this->pos_
);
1397 if (static_cast<off_t
>(rel
.get_r_offset()) >= offset
)
1400 this->pos_
+= this->reloc_size_
;
1405 // Instantiate the templates we need.
1407 #ifdef HAVE_TARGET_32_LITTLE
1410 Sized_relobj
<32, false>::do_read_relocs(Read_relocs_data
* rd
);
1413 #ifdef HAVE_TARGET_32_BIG
1416 Sized_relobj
<32, true>::do_read_relocs(Read_relocs_data
* rd
);
1419 #ifdef HAVE_TARGET_64_LITTLE
1422 Sized_relobj
<64, false>::do_read_relocs(Read_relocs_data
* rd
);
1425 #ifdef HAVE_TARGET_64_BIG
1428 Sized_relobj
<64, true>::do_read_relocs(Read_relocs_data
* rd
);
1431 #ifdef HAVE_TARGET_32_LITTLE
1434 Sized_relobj
<32, false>::do_gc_process_relocs(const General_options
& options
,
1435 Symbol_table
* symtab
,
1437 Read_relocs_data
* rd
);
1440 #ifdef HAVE_TARGET_32_BIG
1443 Sized_relobj
<32, true>::do_gc_process_relocs(const General_options
& options
,
1444 Symbol_table
* symtab
,
1446 Read_relocs_data
* rd
);
1449 #ifdef HAVE_TARGET_64_LITTLE
1452 Sized_relobj
<64, false>::do_gc_process_relocs(const General_options
& options
,
1453 Symbol_table
* symtab
,
1455 Read_relocs_data
* rd
);
1458 #ifdef HAVE_TARGET_64_BIG
1461 Sized_relobj
<64, true>::do_gc_process_relocs(const General_options
& options
,
1462 Symbol_table
* symtab
,
1464 Read_relocs_data
* rd
);
1467 #ifdef HAVE_TARGET_32_LITTLE
1470 Sized_relobj
<32, false>::do_scan_relocs(const General_options
& options
,
1471 Symbol_table
* symtab
,
1473 Read_relocs_data
* rd
);
1476 #ifdef HAVE_TARGET_32_BIG
1479 Sized_relobj
<32, true>::do_scan_relocs(const General_options
& options
,
1480 Symbol_table
* symtab
,
1482 Read_relocs_data
* rd
);
1485 #ifdef HAVE_TARGET_64_LITTLE
1488 Sized_relobj
<64, false>::do_scan_relocs(const General_options
& options
,
1489 Symbol_table
* symtab
,
1491 Read_relocs_data
* rd
);
1494 #ifdef HAVE_TARGET_64_BIG
1497 Sized_relobj
<64, true>::do_scan_relocs(const General_options
& options
,
1498 Symbol_table
* symtab
,
1500 Read_relocs_data
* rd
);
1503 #ifdef HAVE_TARGET_32_LITTLE
1506 Sized_relobj
<32, false>::do_relocate(const General_options
& options
,
1507 const Symbol_table
* symtab
,
1508 const Layout
* layout
,
1512 #ifdef HAVE_TARGET_32_BIG
1515 Sized_relobj
<32, true>::do_relocate(const General_options
& options
,
1516 const Symbol_table
* symtab
,
1517 const Layout
* layout
,
1521 #ifdef HAVE_TARGET_64_LITTLE
1524 Sized_relobj
<64, false>::do_relocate(const General_options
& options
,
1525 const Symbol_table
* symtab
,
1526 const Layout
* layout
,
1530 #ifdef HAVE_TARGET_64_BIG
1533 Sized_relobj
<64, true>::do_relocate(const General_options
& options
,
1534 const Symbol_table
* symtab
,
1535 const Layout
* layout
,
1539 #ifdef HAVE_TARGET_32_LITTLE
1542 Sized_relobj
<32, false>::do_relocate_sections(
1543 const General_options
& options
,
1544 const Symbol_table
* symtab
,
1545 const Layout
* layout
,
1546 const unsigned char* pshdrs
,
1550 #ifdef HAVE_TARGET_32_BIG
1553 Sized_relobj
<32, true>::do_relocate_sections(
1554 const General_options
& options
,
1555 const Symbol_table
* symtab
,
1556 const Layout
* layout
,
1557 const unsigned char* pshdrs
,
1561 #ifdef HAVE_TARGET_64_LITTLE
1564 Sized_relobj
<64, false>::do_relocate_sections(
1565 const General_options
& options
,
1566 const Symbol_table
* symtab
,
1567 const Layout
* layout
,
1568 const unsigned char* pshdrs
,
1572 #ifdef HAVE_TARGET_64_BIG
1575 Sized_relobj
<64, true>::do_relocate_sections(
1576 const General_options
& options
,
1577 const Symbol_table
* symtab
,
1578 const Layout
* layout
,
1579 const unsigned char* pshdrs
,
1583 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1585 class Merged_symbol_value
<32>;
1588 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1590 class Merged_symbol_value
<64>;
1593 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1595 class Symbol_value
<32>;
1598 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1600 class Symbol_value
<64>;
1603 #ifdef HAVE_TARGET_32_LITTLE
1605 class Track_relocs
<32, false>;
1608 #ifdef HAVE_TARGET_32_BIG
1610 class Track_relocs
<32, true>;
1613 #ifdef HAVE_TARGET_64_LITTLE
1615 class Track_relocs
<64, false>;
1618 #ifdef HAVE_TARGET_64_BIG
1620 class Track_relocs
<64, true>;
1623 } // End namespace gold.