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->symtab_
,
83 workqueue
->queue_next(new Scan_relocs(this->symtab_
, this->layout_
,
90 // Return a debugging name for the task.
93 Read_relocs::get_name() const
95 return "Read_relocs " + this->object_
->name();
98 // Gc_process_relocs methods.
100 // These tasks process the relocations read by Read_relocs and
101 // determine which sections are referenced and which are garbage.
102 // This task is done only when --gc-sections is used.
105 Gc_process_relocs::is_runnable()
107 if (this->object_
->is_locked())
108 return this->object_
->token();
113 Gc_process_relocs::locks(Task_locker
* tl
)
115 tl
->add(this, this->object_
->token());
116 tl
->add(this, this->blocker_
);
120 Gc_process_relocs::run(Workqueue
*)
122 this->object_
->gc_process_relocs(this->symtab_
, this->layout_
, this->rd_
);
123 this->object_
->release();
126 // Return a debugging name for the task.
129 Gc_process_relocs::get_name() const
131 return "Gc_process_relocs " + this->object_
->name();
134 // Scan_relocs methods.
136 // These tasks scan the relocations read by Read_relocs and mark up
137 // the symbol table to indicate which relocations are required. We
138 // use a lock on the symbol table to keep them from interfering with
142 Scan_relocs::is_runnable()
144 if (!this->symtab_lock_
->is_writable())
145 return this->symtab_lock_
;
146 if (this->object_
->is_locked())
147 return this->object_
->token();
151 // Return the locks we hold: one on the file, one on the symbol table
155 Scan_relocs::locks(Task_locker
* tl
)
157 tl
->add(this, this->object_
->token());
158 tl
->add(this, this->symtab_lock_
);
159 tl
->add(this, this->blocker_
);
165 Scan_relocs::run(Workqueue
*)
167 this->object_
->scan_relocs(this->symtab_
, this->layout_
, this->rd_
);
168 this->object_
->release();
173 // Return a debugging name for the task.
176 Scan_relocs::get_name() const
178 return "Scan_relocs " + this->object_
->name();
181 // Relocate_task methods.
183 // We may have to wait for the output sections to be written.
186 Relocate_task::is_runnable()
188 if (this->object_
->relocs_must_follow_section_writes()
189 && this->output_sections_blocker_
->is_blocked())
190 return this->output_sections_blocker_
;
192 if (this->object_
->is_locked())
193 return this->object_
->token();
198 // We want to lock the file while we run. We want to unblock
199 // INPUT_SECTIONS_BLOCKER and FINAL_BLOCKER when we are done.
200 // INPUT_SECTIONS_BLOCKER may be NULL.
203 Relocate_task::locks(Task_locker
* tl
)
205 if (this->input_sections_blocker_
!= NULL
)
206 tl
->add(this, this->input_sections_blocker_
);
207 tl
->add(this, this->final_blocker_
);
208 tl
->add(this, this->object_
->token());
214 Relocate_task::run(Workqueue
*)
216 this->object_
->relocate(this->symtab_
, this->layout_
, this->of_
);
218 // This is normally the last thing we will do with an object, so
219 // uncache all views.
220 this->object_
->clear_view_cache_marks();
222 this->object_
->release();
225 // Return a debugging name for the task.
228 Relocate_task::get_name() const
230 return "Relocate_task " + this->object_
->name();
233 // Read the relocs and local symbols from the object file and store
234 // the information in RD.
236 template<int size
, bool big_endian
>
238 Sized_relobj
<size
, big_endian
>::do_read_relocs(Read_relocs_data
* rd
)
242 unsigned int shnum
= this->shnum();
246 rd
->relocs
.reserve(shnum
/ 2);
248 const Output_sections
& out_sections(this->output_sections());
249 const std::vector
<Address
>& out_offsets(this->section_offsets_
);
251 const unsigned char *pshdrs
= this->get_view(this->elf_file_
.shoff(),
252 shnum
* This::shdr_size
,
254 // Skip the first, dummy, section.
255 const unsigned char *ps
= pshdrs
+ This::shdr_size
;
256 for (unsigned int i
= 1; i
< shnum
; ++i
, ps
+= This::shdr_size
)
258 typename
This::Shdr
shdr(ps
);
260 unsigned int sh_type
= shdr
.get_sh_type();
261 if (sh_type
!= elfcpp::SHT_REL
&& sh_type
!= elfcpp::SHT_RELA
)
264 unsigned int shndx
= this->adjust_shndx(shdr
.get_sh_info());
267 this->error(_("relocation section %u has bad info %u"),
272 Output_section
* os
= out_sections
[shndx
];
276 // We are scanning relocations in order to fill out the GOT and
277 // PLT sections. Relocations for sections which are not
278 // allocated (typically debugging sections) should not add new
279 // GOT and PLT entries. So we skip them unless this is a
280 // relocatable link or we need to emit relocations. FIXME: What
281 // should we do if a linker script maps a section with SHF_ALLOC
282 // clear to a section with SHF_ALLOC set?
283 typename
This::Shdr
secshdr(pshdrs
+ shndx
* This::shdr_size
);
284 bool is_section_allocated
= ((secshdr
.get_sh_flags() & elfcpp::SHF_ALLOC
)
286 if (!is_section_allocated
287 && !parameters
->options().relocatable()
288 && !parameters
->options().emit_relocs())
291 if (this->adjust_shndx(shdr
.get_sh_link()) != this->symtab_shndx_
)
293 this->error(_("relocation section %u uses unexpected "
295 i
, this->adjust_shndx(shdr
.get_sh_link()));
299 off_t sh_size
= shdr
.get_sh_size();
301 unsigned int reloc_size
;
302 if (sh_type
== elfcpp::SHT_REL
)
303 reloc_size
= elfcpp::Elf_sizes
<size
>::rel_size
;
305 reloc_size
= elfcpp::Elf_sizes
<size
>::rela_size
;
306 if (reloc_size
!= shdr
.get_sh_entsize())
308 this->error(_("unexpected entsize for reloc section %u: %lu != %u"),
309 i
, static_cast<unsigned long>(shdr
.get_sh_entsize()),
314 size_t reloc_count
= sh_size
/ reloc_size
;
315 if (static_cast<off_t
>(reloc_count
* reloc_size
) != sh_size
)
317 this->error(_("reloc section %u size %lu uneven"),
318 i
, static_cast<unsigned long>(sh_size
));
322 rd
->relocs
.push_back(Section_relocs());
323 Section_relocs
& sr(rd
->relocs
.back());
325 sr
.data_shndx
= shndx
;
326 sr
.contents
= this->get_lasting_view(shdr
.get_sh_offset(), sh_size
,
328 sr
.sh_type
= sh_type
;
329 sr
.reloc_count
= reloc_count
;
330 sr
.output_section
= os
;
331 sr
.needs_special_offset_handling
= out_offsets
[shndx
] == invalid_address
;
332 sr
.is_data_section_allocated
= is_section_allocated
;
335 // Read the local symbols.
336 gold_assert(this->symtab_shndx_
!= -1U);
337 if (this->symtab_shndx_
== 0 || this->local_symbol_count_
== 0)
338 rd
->local_symbols
= NULL
;
341 typename
This::Shdr
symtabshdr(pshdrs
342 + this->symtab_shndx_
* This::shdr_size
);
343 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
344 const int sym_size
= This::sym_size
;
345 const unsigned int loccount
= this->local_symbol_count_
;
346 gold_assert(loccount
== symtabshdr
.get_sh_info());
347 off_t locsize
= loccount
* sym_size
;
348 rd
->local_symbols
= this->get_lasting_view(symtabshdr
.get_sh_offset(),
349 locsize
, true, true);
353 // Process the relocs to generate mappings from source sections to referenced
354 // sections. This is used during garbage colletion to determine garbage
357 template<int size
, bool big_endian
>
359 Sized_relobj
<size
, big_endian
>::do_gc_process_relocs(Symbol_table
* symtab
,
361 Read_relocs_data
* rd
)
363 Sized_target
<size
, big_endian
>* target
=
364 parameters
->sized_target
<size
, big_endian
>();
366 const unsigned char* local_symbols
;
367 if (rd
->local_symbols
== NULL
)
368 local_symbols
= NULL
;
370 local_symbols
= rd
->local_symbols
->data();
372 for (Read_relocs_data::Relocs_list::iterator p
= rd
->relocs
.begin();
373 p
!= rd
->relocs
.end();
376 if (!parameters
->options().relocatable())
378 // As noted above, when not generating an object file, we
379 // only scan allocated sections. We may see a non-allocated
380 // section here if we are emitting relocs.
381 if (p
->is_data_section_allocated
)
382 target
->gc_process_relocs(symtab
, layout
, this,
383 p
->data_shndx
, p
->sh_type
,
384 p
->contents
->data(), p
->reloc_count
,
386 p
->needs_special_offset_handling
,
387 this->local_symbol_count_
,
394 // Scan the relocs and adjust the symbol table. This looks for
395 // relocations which require GOT/PLT/COPY relocations.
397 template<int size
, bool big_endian
>
399 Sized_relobj
<size
, big_endian
>::do_scan_relocs(Symbol_table
* symtab
,
401 Read_relocs_data
* rd
)
403 Sized_target
<size
, big_endian
>* target
=
404 parameters
->sized_target
<size
, big_endian
>();
406 const unsigned char* local_symbols
;
407 if (rd
->local_symbols
== NULL
)
408 local_symbols
= NULL
;
410 local_symbols
= rd
->local_symbols
->data();
412 for (Read_relocs_data::Relocs_list::iterator p
= rd
->relocs
.begin();
413 p
!= rd
->relocs
.end();
416 // When garbage collection is on, unreferenced sections are not included
417 // in the link that would have been included normally. This is known only
418 // after Read_relocs hence this check has to be done again.
419 if (parameters
->options().gc_sections()
420 || parameters
->options().icf_enabled())
422 if (p
->output_section
== NULL
)
425 if (!parameters
->options().relocatable())
427 // As noted above, when not generating an object file, we
428 // only scan allocated sections. We may see a non-allocated
429 // section here if we are emitting relocs.
430 if (p
->is_data_section_allocated
)
431 target
->scan_relocs(symtab
, layout
, this, p
->data_shndx
,
432 p
->sh_type
, p
->contents
->data(),
433 p
->reloc_count
, p
->output_section
,
434 p
->needs_special_offset_handling
,
435 this->local_symbol_count_
,
437 if (parameters
->options().emit_relocs())
438 this->emit_relocs_scan(symtab
, layout
, local_symbols
, p
);
442 Relocatable_relocs
* rr
= this->relocatable_relocs(p
->reloc_shndx
);
443 gold_assert(rr
!= NULL
);
444 rr
->set_reloc_count(p
->reloc_count
);
445 target
->scan_relocatable_relocs(symtab
, layout
, this,
446 p
->data_shndx
, p
->sh_type
,
450 p
->needs_special_offset_handling
,
451 this->local_symbol_count_
,
460 if (rd
->local_symbols
!= NULL
)
462 delete rd
->local_symbols
;
463 rd
->local_symbols
= NULL
;
467 // This is a strategy class we use when scanning for --emit-relocs.
469 template<int sh_type
>
470 class Emit_relocs_strategy
473 // A local non-section symbol.
474 inline Relocatable_relocs::Reloc_strategy
475 local_non_section_strategy(unsigned int, Relobj
*, unsigned int)
476 { return Relocatable_relocs::RELOC_COPY
; }
478 // A local section symbol.
479 inline Relocatable_relocs::Reloc_strategy
480 local_section_strategy(unsigned int, Relobj
*)
482 if (sh_type
== elfcpp::SHT_RELA
)
483 return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA
;
486 // The addend is stored in the section contents. Since this
487 // is not a relocatable link, we are going to apply the
488 // relocation contents to the section as usual. This means
489 // that we have no way to record the original addend. If the
490 // original addend is not zero, there is basically no way for
491 // the user to handle this correctly. Caveat emptor.
492 return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0
;
497 inline Relocatable_relocs::Reloc_strategy
498 global_strategy(unsigned int, Relobj
*, unsigned int)
499 { return Relocatable_relocs::RELOC_COPY
; }
502 // Scan the input relocations for --emit-relocs.
504 template<int size
, bool big_endian
>
506 Sized_relobj
<size
, big_endian
>::emit_relocs_scan(
507 Symbol_table
* symtab
,
509 const unsigned char* plocal_syms
,
510 const Read_relocs_data::Relocs_list::iterator
& p
)
512 Relocatable_relocs
* rr
= this->relocatable_relocs(p
->reloc_shndx
);
513 gold_assert(rr
!= NULL
);
514 rr
->set_reloc_count(p
->reloc_count
);
516 if (p
->sh_type
== elfcpp::SHT_REL
)
517 this->emit_relocs_scan_reltype
<elfcpp::SHT_REL
>(symtab
, layout
,
521 gold_assert(p
->sh_type
== elfcpp::SHT_RELA
);
522 this->emit_relocs_scan_reltype
<elfcpp::SHT_RELA
>(symtab
, layout
,
527 // Scan the input relocation for --emit-relocs, templatized on the
528 // type of the relocation section.
530 template<int size
, bool big_endian
>
531 template<int sh_type
>
533 Sized_relobj
<size
, big_endian
>::emit_relocs_scan_reltype(
534 Symbol_table
* symtab
,
536 const unsigned char* plocal_syms
,
537 const Read_relocs_data::Relocs_list::iterator
& p
,
538 Relocatable_relocs
* rr
)
540 scan_relocatable_relocs
<size
, big_endian
, sh_type
,
541 Emit_relocs_strategy
<sh_type
> >(
549 p
->needs_special_offset_handling
,
550 this->local_symbol_count_
,
555 // Relocate the input sections and write out the local symbols.
557 template<int size
, bool big_endian
>
559 Sized_relobj
<size
, big_endian
>::do_relocate(const Symbol_table
* symtab
,
560 const Layout
* layout
,
563 unsigned int shnum
= this->shnum();
565 // Read the section headers.
566 const unsigned char* pshdrs
= this->get_view(this->elf_file_
.shoff(),
567 shnum
* This::shdr_size
,
573 // Make two passes over the sections. The first one copies the
574 // section data to the output file. The second one applies
577 this->write_sections(pshdrs
, of
, &views
);
579 // To speed up relocations, we set up hash tables for fast lookup of
580 // input offsets to output addresses.
581 this->initialize_input_to_output_maps();
583 // Apply relocations.
585 this->relocate_sections(symtab
, layout
, pshdrs
, &views
);
587 // After we've done the relocations, we release the hash tables,
588 // since we no longer need them.
589 this->free_input_to_output_maps();
591 // Write out the accumulated views.
592 for (unsigned int i
= 1; i
< shnum
; ++i
)
594 if (views
[i
].view
!= NULL
)
596 if (!views
[i
].is_postprocessing_view
)
598 if (views
[i
].is_input_output_view
)
599 of
->write_input_output_view(views
[i
].offset
,
603 of
->write_output_view(views
[i
].offset
, views
[i
].view_size
,
609 // Write out the local symbols.
610 this->write_local_symbols(of
, layout
->sympool(), layout
->dynpool(),
611 layout
->symtab_xindex(), layout
->dynsym_xindex());
613 // We should no longer need the local symbol values.
614 this->clear_local_symbols();
617 // Sort a Read_multiple vector by file offset.
618 struct Read_multiple_compare
621 operator()(const File_read::Read_multiple_entry
& rme1
,
622 const File_read::Read_multiple_entry
& rme2
) const
623 { return rme1
.file_offset
< rme2
.file_offset
; }
626 // Write section data to the output file. PSHDRS points to the
627 // section headers. Record the views in *PVIEWS for use when
630 template<int size
, bool big_endian
>
632 Sized_relobj
<size
, big_endian
>::write_sections(const unsigned char* pshdrs
,
636 unsigned int shnum
= this->shnum();
637 const Output_sections
& out_sections(this->output_sections());
638 const std::vector
<Address
>& out_offsets(this->section_offsets_
);
640 File_read::Read_multiple rm
;
641 bool is_sorted
= true;
643 const unsigned char* p
= pshdrs
+ This::shdr_size
;
644 for (unsigned int i
= 1; i
< shnum
; ++i
, p
+= This::shdr_size
)
646 View_size
* pvs
= &(*pviews
)[i
];
650 const Output_section
* os
= out_sections
[i
];
653 Address output_offset
= out_offsets
[i
];
655 typename
This::Shdr
shdr(p
);
657 if (shdr
.get_sh_type() == elfcpp::SHT_NOBITS
)
660 if ((parameters
->options().relocatable()
661 || parameters
->options().emit_relocs())
662 && (shdr
.get_sh_type() == elfcpp::SHT_REL
663 || shdr
.get_sh_type() == elfcpp::SHT_RELA
)
664 && (shdr
.get_sh_flags() & elfcpp::SHF_ALLOC
) == 0)
666 // This is a reloc section in a relocatable link or when
667 // emitting relocs. We don't need to read the input file.
668 // The size and file offset are stored in the
669 // Relocatable_relocs structure.
670 Relocatable_relocs
* rr
= this->relocatable_relocs(i
);
671 gold_assert(rr
!= NULL
);
672 Output_data
* posd
= rr
->output_data();
673 gold_assert(posd
!= NULL
);
675 pvs
->offset
= posd
->offset();
676 pvs
->view_size
= posd
->data_size();
677 pvs
->view
= of
->get_output_view(pvs
->offset
, pvs
->view_size
);
678 pvs
->address
= posd
->address();
679 pvs
->is_input_output_view
= false;
680 pvs
->is_postprocessing_view
= false;
685 // In the normal case, this input section is simply mapped to
686 // the output section at offset OUTPUT_OFFSET.
688 // However, if OUTPUT_OFFSET == INVALID_ADDRESS, then input data is
689 // handled specially--e.g., a .eh_frame section. The relocation
690 // routines need to check for each reloc where it should be
691 // applied. For this case, we need an input/output view for the
692 // entire contents of the section in the output file. We don't
693 // want to copy the contents of the input section to the output
694 // section; the output section contents were already written,
695 // and we waited for them in Relocate_task::is_runnable because
696 // relocs_must_follow_section_writes is set for the object.
698 // Regardless of which of the above cases is true, we have to
699 // check requires_postprocessing of the output section. If that
700 // is false, then we work with views of the output file
701 // directly. If it is true, then we work with a separate
702 // buffer, and the output section is responsible for writing the
703 // final data to the output file.
705 off_t output_section_offset
;
706 Address output_section_size
;
707 if (!os
->requires_postprocessing())
709 output_section_offset
= os
->offset();
710 output_section_size
= convert_types
<Address
, off_t
>(os
->data_size());
714 output_section_offset
= 0;
715 output_section_size
=
716 convert_types
<Address
, off_t
>(os
->postprocessing_buffer_size());
720 section_size_type view_size
;
721 if (output_offset
!= invalid_address
)
723 view_start
= output_section_offset
+ output_offset
;
724 view_size
= convert_to_section_size_type(shdr
.get_sh_size());
728 view_start
= output_section_offset
;
729 view_size
= convert_to_section_size_type(output_section_size
);
735 gold_assert(output_offset
== invalid_address
736 || output_offset
+ view_size
<= output_section_size
);
739 if (os
->requires_postprocessing())
741 unsigned char* buffer
= os
->postprocessing_buffer();
742 view
= buffer
+ view_start
;
743 if (output_offset
!= invalid_address
)
745 off_t sh_offset
= shdr
.get_sh_offset();
746 if (!rm
.empty() && rm
.back().file_offset
> sh_offset
)
748 rm
.push_back(File_read::Read_multiple_entry(sh_offset
,
754 if (output_offset
== invalid_address
)
755 view
= of
->get_input_output_view(view_start
, view_size
);
758 view
= of
->get_output_view(view_start
, view_size
);
759 off_t sh_offset
= shdr
.get_sh_offset();
760 if (!rm
.empty() && rm
.back().file_offset
> sh_offset
)
762 rm
.push_back(File_read::Read_multiple_entry(sh_offset
,
768 pvs
->address
= os
->address();
769 if (output_offset
!= invalid_address
)
770 pvs
->address
+= output_offset
;
771 pvs
->offset
= view_start
;
772 pvs
->view_size
= view_size
;
773 pvs
->is_input_output_view
= output_offset
== invalid_address
;
774 pvs
->is_postprocessing_view
= os
->requires_postprocessing();
777 // Actually read the data.
781 std::sort(rm
.begin(), rm
.end(), Read_multiple_compare());
782 this->read_multiple(rm
);
786 // Relocate section data. VIEWS points to the section data as views
787 // in the output file.
789 template<int size
, bool big_endian
>
791 Sized_relobj
<size
, big_endian
>::do_relocate_sections(
792 const Symbol_table
* symtab
,
793 const Layout
* layout
,
794 const unsigned char* pshdrs
,
797 unsigned int shnum
= this->shnum();
798 Sized_target
<size
, big_endian
>* target
=
799 parameters
->sized_target
<size
, big_endian
>();
801 const Output_sections
& out_sections(this->output_sections());
802 const std::vector
<Address
>& out_offsets(this->section_offsets_
);
804 Relocate_info
<size
, big_endian
> relinfo
;
805 relinfo
.symtab
= symtab
;
806 relinfo
.layout
= layout
;
807 relinfo
.object
= this;
809 const unsigned char* p
= pshdrs
+ This::shdr_size
;
810 for (unsigned int i
= 1; i
< shnum
; ++i
, p
+= This::shdr_size
)
812 typename
This::Shdr
shdr(p
);
814 unsigned int sh_type
= shdr
.get_sh_type();
815 if (sh_type
!= elfcpp::SHT_REL
&& sh_type
!= elfcpp::SHT_RELA
)
818 off_t sh_size
= shdr
.get_sh_size();
822 unsigned int index
= this->adjust_shndx(shdr
.get_sh_info());
823 if (index
>= this->shnum())
825 this->error(_("relocation section %u has bad info %u"),
830 Output_section
* os
= out_sections
[index
];
833 // This relocation section is against a section which we
837 Address output_offset
= out_offsets
[index
];
839 gold_assert((*pviews
)[index
].view
!= NULL
);
840 if (parameters
->options().relocatable())
841 gold_assert((*pviews
)[i
].view
!= NULL
);
843 if (this->adjust_shndx(shdr
.get_sh_link()) != this->symtab_shndx_
)
845 gold_error(_("relocation section %u uses unexpected "
847 i
, this->adjust_shndx(shdr
.get_sh_link()));
851 const unsigned char* prelocs
= this->get_view(shdr
.get_sh_offset(),
852 sh_size
, true, false);
854 unsigned int reloc_size
;
855 if (sh_type
== elfcpp::SHT_REL
)
856 reloc_size
= elfcpp::Elf_sizes
<size
>::rel_size
;
858 reloc_size
= elfcpp::Elf_sizes
<size
>::rela_size
;
860 if (reloc_size
!= shdr
.get_sh_entsize())
862 gold_error(_("unexpected entsize for reloc section %u: %lu != %u"),
863 i
, static_cast<unsigned long>(shdr
.get_sh_entsize()),
868 size_t reloc_count
= sh_size
/ reloc_size
;
869 if (static_cast<off_t
>(reloc_count
* reloc_size
) != sh_size
)
871 gold_error(_("reloc section %u size %lu uneven"),
872 i
, static_cast<unsigned long>(sh_size
));
876 gold_assert(output_offset
!= invalid_address
877 || this->relocs_must_follow_section_writes());
879 relinfo
.reloc_shndx
= i
;
880 relinfo
.reloc_shdr
= p
;
881 relinfo
.data_shndx
= index
;
882 relinfo
.data_shdr
= pshdrs
+ index
* This::shdr_size
;
883 unsigned char* view
= (*pviews
)[index
].view
;
884 Address address
= (*pviews
)[index
].address
;
885 section_size_type view_size
= (*pviews
)[index
].view_size
;
887 Reloc_symbol_changes
* reloc_map
= NULL
;
888 if (this->uses_split_stack() && output_offset
!= invalid_address
)
890 typename
This::Shdr
data_shdr(pshdrs
+ index
* This::shdr_size
);
891 if ((data_shdr
.get_sh_flags() & elfcpp::SHF_EXECINSTR
) != 0)
892 this->split_stack_adjust(symtab
, pshdrs
, sh_type
, index
,
893 prelocs
, reloc_count
, view
, view_size
,
897 if (!parameters
->options().relocatable())
899 target
->relocate_section(&relinfo
, sh_type
, prelocs
, reloc_count
, os
,
900 output_offset
== invalid_address
,
901 view
, address
, view_size
, reloc_map
);
902 if (parameters
->options().emit_relocs())
903 this->emit_relocs(&relinfo
, i
, sh_type
, prelocs
, reloc_count
,
904 os
, output_offset
, view
, address
, view_size
,
905 (*pviews
)[i
].view
, (*pviews
)[i
].view_size
);
909 Relocatable_relocs
* rr
= this->relocatable_relocs(i
);
910 target
->relocate_for_relocatable(&relinfo
, sh_type
, prelocs
,
911 reloc_count
, os
, output_offset
, rr
,
912 view
, address
, view_size
,
914 (*pviews
)[i
].view_size
);
919 // Emit the relocs for --emit-relocs.
921 template<int size
, bool big_endian
>
923 Sized_relobj
<size
, big_endian
>::emit_relocs(
924 const Relocate_info
<size
, big_endian
>* relinfo
,
926 unsigned int sh_type
,
927 const unsigned char* prelocs
,
929 Output_section
* output_section
,
930 typename
elfcpp::Elf_types
<size
>::Elf_Addr offset_in_output_section
,
932 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
,
933 section_size_type view_size
,
934 unsigned char* reloc_view
,
935 section_size_type reloc_view_size
)
937 if (sh_type
== elfcpp::SHT_REL
)
938 this->emit_relocs_reltype
<elfcpp::SHT_REL
>(relinfo
, i
, prelocs
,
939 reloc_count
, output_section
,
940 offset_in_output_section
,
941 view
, address
, view_size
,
942 reloc_view
, reloc_view_size
);
945 gold_assert(sh_type
== elfcpp::SHT_RELA
);
946 this->emit_relocs_reltype
<elfcpp::SHT_RELA
>(relinfo
, i
, prelocs
,
947 reloc_count
, output_section
,
948 offset_in_output_section
,
949 view
, address
, view_size
,
950 reloc_view
, reloc_view_size
);
954 // Emit the relocs for --emit-relocs, templatized on the type of the
955 // relocation section.
957 template<int size
, bool big_endian
>
958 template<int sh_type
>
960 Sized_relobj
<size
, big_endian
>::emit_relocs_reltype(
961 const Relocate_info
<size
, big_endian
>* relinfo
,
963 const unsigned char* prelocs
,
965 Output_section
* output_section
,
966 typename
elfcpp::Elf_types
<size
>::Elf_Addr offset_in_output_section
,
968 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
,
969 section_size_type view_size
,
970 unsigned char* reloc_view
,
971 section_size_type reloc_view_size
)
973 const Relocatable_relocs
* rr
= this->relocatable_relocs(i
);
974 relocate_for_relocatable
<size
, big_endian
, sh_type
>(
979 offset_in_output_section
,
988 // Create merge hash tables for the local symbols. These are used to
989 // speed up relocations.
991 template<int size
, bool big_endian
>
993 Sized_relobj
<size
, big_endian
>::initialize_input_to_output_maps()
995 const unsigned int loccount
= this->local_symbol_count_
;
996 for (unsigned int i
= 1; i
< loccount
; ++i
)
998 Symbol_value
<size
>& lv(this->local_values_
[i
]);
999 lv
.initialize_input_to_output_map(this);
1003 // Free merge hash tables for the local symbols.
1005 template<int size
, bool big_endian
>
1007 Sized_relobj
<size
, big_endian
>::free_input_to_output_maps()
1009 const unsigned int loccount
= this->local_symbol_count_
;
1010 for (unsigned int i
= 1; i
< loccount
; ++i
)
1012 Symbol_value
<size
>& lv(this->local_values_
[i
]);
1013 lv
.free_input_to_output_map();
1017 // If an object was compiled with -fsplit-stack, this is called to
1018 // check whether any relocations refer to functions defined in objects
1019 // which were not compiled with -fsplit-stack. If they were, then we
1020 // need to apply some target-specific adjustments to request
1021 // additional stack space.
1023 template<int size
, bool big_endian
>
1025 Sized_relobj
<size
, big_endian
>::split_stack_adjust(
1026 const Symbol_table
* symtab
,
1027 const unsigned char* pshdrs
,
1028 unsigned int sh_type
,
1030 const unsigned char* prelocs
,
1032 unsigned char* view
,
1033 section_size_type view_size
,
1034 Reloc_symbol_changes
** reloc_map
)
1036 if (sh_type
== elfcpp::SHT_REL
)
1037 this->split_stack_adjust_reltype
<elfcpp::SHT_REL
>(symtab
, pshdrs
, shndx
,
1038 prelocs
, reloc_count
,
1043 gold_assert(sh_type
== elfcpp::SHT_RELA
);
1044 this->split_stack_adjust_reltype
<elfcpp::SHT_RELA
>(symtab
, pshdrs
, shndx
,
1045 prelocs
, reloc_count
,
1051 // Adjust for -fsplit-stack, templatized on the type of the relocation
1054 template<int size
, bool big_endian
>
1055 template<int sh_type
>
1057 Sized_relobj
<size
, big_endian
>::split_stack_adjust_reltype(
1058 const Symbol_table
* symtab
,
1059 const unsigned char* pshdrs
,
1061 const unsigned char* prelocs
,
1063 unsigned char* view
,
1064 section_size_type view_size
,
1065 Reloc_symbol_changes
** reloc_map
)
1067 typedef typename Reloc_types
<sh_type
, size
, big_endian
>::Reloc Reltype
;
1068 const int reloc_size
= Reloc_types
<sh_type
, size
, big_endian
>::reloc_size
;
1070 size_t local_count
= this->local_symbol_count();
1072 std::vector
<section_offset_type
> non_split_refs
;
1074 const unsigned char* pr
= prelocs
;
1075 for (size_t i
= 0; i
< reloc_count
; ++i
, pr
+= reloc_size
)
1079 typename
elfcpp::Elf_types
<size
>::Elf_WXword r_info
= reloc
.get_r_info();
1080 unsigned int r_sym
= elfcpp::elf_r_sym
<size
>(r_info
);
1081 if (r_sym
< local_count
)
1084 const Symbol
* gsym
= this->global_symbol(r_sym
);
1085 gold_assert(gsym
!= NULL
);
1086 if (gsym
->is_forwarder())
1087 gsym
= symtab
->resolve_forwards(gsym
);
1089 // See if this relocation refers to a function defined in an
1090 // object compiled without -fsplit-stack. Note that we don't
1091 // care about the type of relocation--this means that in some
1092 // cases we will ask for a large stack unnecessarily, but this
1093 // is not fatal. FIXME: Some targets have symbols which are
1094 // functions but are not type STT_FUNC, e.g., STT_ARM_TFUNC.
1095 if (gsym
->type() == elfcpp::STT_FUNC
1096 && !gsym
->is_undefined()
1097 && gsym
->source() == Symbol::FROM_OBJECT
1098 && !gsym
->object()->uses_split_stack())
1100 section_offset_type offset
=
1101 convert_to_section_size_type(reloc
.get_r_offset());
1102 non_split_refs
.push_back(offset
);
1106 if (non_split_refs
.empty())
1109 // At this point, every entry in NON_SPLIT_REFS indicates a
1110 // relocation which refers to a function in an object compiled
1111 // without -fsplit-stack. We now have to convert that list into a
1112 // set of offsets to functions. First, we find all the functions.
1114 Function_offsets function_offsets
;
1115 this->find_functions(pshdrs
, shndx
, &function_offsets
);
1116 if (function_offsets
.empty())
1119 // Now get a list of the function with references to non split-stack
1122 Function_offsets calls_non_split
;
1123 for (std::vector
<section_offset_type
>::const_iterator p
1124 = non_split_refs
.begin();
1125 p
!= non_split_refs
.end();
1128 Function_offsets::const_iterator low
= function_offsets
.lower_bound(*p
);
1129 if (low
== function_offsets
.end())
1131 else if (low
->first
== *p
)
1133 else if (low
== function_offsets
.begin())
1138 calls_non_split
.insert(*low
);
1140 if (calls_non_split
.empty())
1143 // Now we have a set of functions to adjust. The adjustments are
1144 // target specific. Besides changing the output section view
1145 // however, it likes, the target may request a relocation change
1146 // from one global symbol name to another.
1148 for (Function_offsets::const_iterator p
= calls_non_split
.begin();
1149 p
!= calls_non_split
.end();
1154 parameters
->target().calls_non_split(this, shndx
, p
->first
, p
->second
,
1155 view
, view_size
, &from
, &to
);
1158 gold_assert(!to
.empty());
1159 Symbol
* tosym
= NULL
;
1161 // Find relocations in the relevant function which are for
1164 for (size_t i
= 0; i
< reloc_count
; ++i
, pr
+= reloc_size
)
1168 typename
elfcpp::Elf_types
<size
>::Elf_WXword r_info
=
1170 unsigned int r_sym
= elfcpp::elf_r_sym
<size
>(r_info
);
1171 if (r_sym
< local_count
)
1174 section_offset_type offset
=
1175 convert_to_section_size_type(reloc
.get_r_offset());
1176 if (offset
< p
->first
1179 + static_cast<section_offset_type
>(p
->second
))))
1182 const Symbol
* gsym
= this->global_symbol(r_sym
);
1183 if (from
== gsym
->name())
1187 tosym
= symtab
->lookup(to
.c_str());
1190 this->error(_("could not convert call "
1192 from
.c_str(), to
.c_str());
1197 if (*reloc_map
== NULL
)
1198 *reloc_map
= new Reloc_symbol_changes(reloc_count
);
1199 (*reloc_map
)->set(i
, tosym
);
1206 // Find all the function in this object defined in section SHNDX.
1207 // Store their offsets in the section in FUNCTION_OFFSETS.
1209 template<int size
, bool big_endian
>
1211 Sized_relobj
<size
, big_endian
>::find_functions(
1212 const unsigned char* pshdrs
,
1214 Sized_relobj
<size
, big_endian
>::Function_offsets
* function_offsets
)
1216 // We need to read the symbols to find the functions. If we wanted
1217 // to, we could cache reading the symbols across all sections in the
1219 const unsigned int symtab_shndx
= this->symtab_shndx_
;
1220 typename
This::Shdr
symtabshdr(pshdrs
+ symtab_shndx
* This::shdr_size
);
1221 gold_assert(symtabshdr
.get_sh_type() == elfcpp::SHT_SYMTAB
);
1223 typename
elfcpp::Elf_types
<size
>::Elf_WXword sh_size
=
1224 symtabshdr
.get_sh_size();
1225 const unsigned char* psyms
= this->get_view(symtabshdr
.get_sh_offset(),
1226 sh_size
, true, true);
1228 const int sym_size
= This::sym_size
;
1229 const unsigned int symcount
= sh_size
/ sym_size
;
1230 for (unsigned int i
= 0; i
< symcount
; ++i
, psyms
+= sym_size
)
1232 typename
elfcpp::Sym
<size
, big_endian
> isym(psyms
);
1234 // FIXME: Some targets can have functions which do not have type
1235 // STT_FUNC, e.g., STT_ARM_TFUNC.
1236 if (isym
.get_st_type() != elfcpp::STT_FUNC
1237 || isym
.get_st_size() == 0)
1241 unsigned int sym_shndx
= this->adjust_sym_shndx(i
, isym
.get_st_shndx(),
1243 if (!is_ordinary
|| sym_shndx
!= shndx
)
1246 section_offset_type value
=
1247 convert_to_section_size_type(isym
.get_st_value());
1248 section_size_type fnsize
=
1249 convert_to_section_size_type(isym
.get_st_size());
1251 (*function_offsets
)[value
] = fnsize
;
1255 // Class Merged_symbol_value.
1259 Merged_symbol_value
<size
>::initialize_input_to_output_map(
1260 const Relobj
* object
,
1261 unsigned int input_shndx
)
1263 Object_merge_map
* map
= object
->merge_map();
1264 map
->initialize_input_to_output_map
<size
>(input_shndx
,
1265 this->output_start_address_
,
1266 &this->output_addresses_
);
1269 // Get the output value corresponding to an input offset if we
1270 // couldn't find it in the hash table.
1273 typename
elfcpp::Elf_types
<size
>::Elf_Addr
1274 Merged_symbol_value
<size
>::value_from_output_section(
1275 const Relobj
* object
,
1276 unsigned int input_shndx
,
1277 typename
elfcpp::Elf_types
<size
>::Elf_Addr input_offset
) const
1279 section_offset_type output_offset
;
1280 bool found
= object
->merge_map()->get_output_offset(NULL
, input_shndx
,
1284 // If this assertion fails, it means that some relocation was
1285 // against a portion of an input merge section which we didn't map
1286 // to the output file and we didn't explicitly discard. We should
1287 // always map all portions of input merge sections.
1290 if (output_offset
== -1)
1293 return this->output_start_address_
+ output_offset
;
1296 // Track_relocs methods.
1298 // Initialize the class to track the relocs. This gets the object,
1299 // the reloc section index, and the type of the relocs. This returns
1300 // false if something goes wrong.
1302 template<int size
, bool big_endian
>
1304 Track_relocs
<size
, big_endian
>::initialize(
1306 unsigned int reloc_shndx
,
1307 unsigned int reloc_type
)
1309 // If RELOC_SHNDX is -1U, it means there is more than one reloc
1310 // section for the .eh_frame section. We can't handle that case.
1311 if (reloc_shndx
== -1U)
1314 // If RELOC_SHNDX is 0, there is no reloc section.
1315 if (reloc_shndx
== 0)
1318 // Get the contents of the reloc section.
1319 this->prelocs_
= object
->section_contents(reloc_shndx
, &this->len_
, false);
1321 if (reloc_type
== elfcpp::SHT_REL
)
1322 this->reloc_size_
= elfcpp::Elf_sizes
<size
>::rel_size
;
1323 else if (reloc_type
== elfcpp::SHT_RELA
)
1324 this->reloc_size_
= elfcpp::Elf_sizes
<size
>::rela_size
;
1328 if (this->len_
% this->reloc_size_
!= 0)
1330 object
->error(_("reloc section size %zu is not a multiple of "
1332 static_cast<size_t>(this->len_
),
1340 // Return the offset of the next reloc, or -1 if there isn't one.
1342 template<int size
, bool big_endian
>
1344 Track_relocs
<size
, big_endian
>::next_offset() const
1346 if (this->pos_
>= this->len_
)
1349 // Rel and Rela start out the same, so we can always use Rel to find
1350 // the r_offset value.
1351 elfcpp::Rel
<size
, big_endian
> rel(this->prelocs_
+ this->pos_
);
1352 return rel
.get_r_offset();
1355 // Return the index of the symbol referenced by the next reloc, or -1U
1356 // if there aren't any more relocs.
1358 template<int size
, bool big_endian
>
1360 Track_relocs
<size
, big_endian
>::next_symndx() const
1362 if (this->pos_
>= this->len_
)
1365 // Rel and Rela start out the same, so we can use Rel to find the
1367 elfcpp::Rel
<size
, big_endian
> rel(this->prelocs_
+ this->pos_
);
1368 return elfcpp::elf_r_sym
<size
>(rel
.get_r_info());
1371 // Advance to the next reloc whose r_offset is greater than or equal
1372 // to OFFSET. Return the number of relocs we skip.
1374 template<int size
, bool big_endian
>
1376 Track_relocs
<size
, big_endian
>::advance(off_t offset
)
1379 while (this->pos_
< this->len_
)
1381 // Rel and Rela start out the same, so we can always use Rel to
1382 // find the r_offset value.
1383 elfcpp::Rel
<size
, big_endian
> rel(this->prelocs_
+ this->pos_
);
1384 if (static_cast<off_t
>(rel
.get_r_offset()) >= offset
)
1387 this->pos_
+= this->reloc_size_
;
1392 // Instantiate the templates we need.
1394 #ifdef HAVE_TARGET_32_LITTLE
1397 Sized_relobj
<32, false>::do_read_relocs(Read_relocs_data
* rd
);
1400 #ifdef HAVE_TARGET_32_BIG
1403 Sized_relobj
<32, true>::do_read_relocs(Read_relocs_data
* rd
);
1406 #ifdef HAVE_TARGET_64_LITTLE
1409 Sized_relobj
<64, false>::do_read_relocs(Read_relocs_data
* rd
);
1412 #ifdef HAVE_TARGET_64_BIG
1415 Sized_relobj
<64, true>::do_read_relocs(Read_relocs_data
* rd
);
1418 #ifdef HAVE_TARGET_32_LITTLE
1421 Sized_relobj
<32, false>::do_gc_process_relocs(Symbol_table
* symtab
,
1423 Read_relocs_data
* rd
);
1426 #ifdef HAVE_TARGET_32_BIG
1429 Sized_relobj
<32, true>::do_gc_process_relocs(Symbol_table
* symtab
,
1431 Read_relocs_data
* rd
);
1434 #ifdef HAVE_TARGET_64_LITTLE
1437 Sized_relobj
<64, false>::do_gc_process_relocs(Symbol_table
* symtab
,
1439 Read_relocs_data
* rd
);
1442 #ifdef HAVE_TARGET_64_BIG
1445 Sized_relobj
<64, true>::do_gc_process_relocs(Symbol_table
* symtab
,
1447 Read_relocs_data
* rd
);
1450 #ifdef HAVE_TARGET_32_LITTLE
1453 Sized_relobj
<32, false>::do_scan_relocs(Symbol_table
* symtab
,
1455 Read_relocs_data
* rd
);
1458 #ifdef HAVE_TARGET_32_BIG
1461 Sized_relobj
<32, true>::do_scan_relocs(Symbol_table
* symtab
,
1463 Read_relocs_data
* rd
);
1466 #ifdef HAVE_TARGET_64_LITTLE
1469 Sized_relobj
<64, false>::do_scan_relocs(Symbol_table
* symtab
,
1471 Read_relocs_data
* rd
);
1474 #ifdef HAVE_TARGET_64_BIG
1477 Sized_relobj
<64, true>::do_scan_relocs(Symbol_table
* symtab
,
1479 Read_relocs_data
* rd
);
1482 #ifdef HAVE_TARGET_32_LITTLE
1485 Sized_relobj
<32, false>::do_relocate(const Symbol_table
* symtab
,
1486 const Layout
* layout
,
1490 #ifdef HAVE_TARGET_32_BIG
1493 Sized_relobj
<32, true>::do_relocate(const Symbol_table
* symtab
,
1494 const Layout
* layout
,
1498 #ifdef HAVE_TARGET_64_LITTLE
1501 Sized_relobj
<64, false>::do_relocate(const Symbol_table
* symtab
,
1502 const Layout
* layout
,
1506 #ifdef HAVE_TARGET_64_BIG
1509 Sized_relobj
<64, true>::do_relocate(const Symbol_table
* symtab
,
1510 const Layout
* layout
,
1514 #ifdef HAVE_TARGET_32_LITTLE
1517 Sized_relobj
<32, false>::do_relocate_sections(
1518 const Symbol_table
* symtab
,
1519 const Layout
* layout
,
1520 const unsigned char* pshdrs
,
1524 #ifdef HAVE_TARGET_32_BIG
1527 Sized_relobj
<32, true>::do_relocate_sections(
1528 const Symbol_table
* symtab
,
1529 const Layout
* layout
,
1530 const unsigned char* pshdrs
,
1534 #ifdef HAVE_TARGET_64_LITTLE
1537 Sized_relobj
<64, false>::do_relocate_sections(
1538 const Symbol_table
* symtab
,
1539 const Layout
* layout
,
1540 const unsigned char* pshdrs
,
1544 #ifdef HAVE_TARGET_64_BIG
1547 Sized_relobj
<64, true>::do_relocate_sections(
1548 const Symbol_table
* symtab
,
1549 const Layout
* layout
,
1550 const unsigned char* pshdrs
,
1554 #ifdef HAVE_TARGET_32_LITTLE
1557 Sized_relobj
<32, false>::initialize_input_to_output_maps();
1561 Sized_relobj
<32, false>::free_input_to_output_maps();
1564 #ifdef HAVE_TARGET_32_BIG
1567 Sized_relobj
<32, true>::initialize_input_to_output_maps();
1571 Sized_relobj
<32, true>::free_input_to_output_maps();
1574 #ifdef HAVE_TARGET_64_LITTLE
1577 Sized_relobj
<64, false>::initialize_input_to_output_maps();
1581 Sized_relobj
<64, false>::free_input_to_output_maps();
1584 #ifdef HAVE_TARGET_64_BIG
1587 Sized_relobj
<64, true>::initialize_input_to_output_maps();
1591 Sized_relobj
<64, true>::free_input_to_output_maps();
1594 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1596 class Merged_symbol_value
<32>;
1599 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1601 class Merged_symbol_value
<64>;
1604 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1606 class Symbol_value
<32>;
1609 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1611 class Symbol_value
<64>;
1614 #ifdef HAVE_TARGET_32_LITTLE
1616 class Track_relocs
<32, false>;
1619 #ifdef HAVE_TARGET_32_BIG
1621 class Track_relocs
<32, true>;
1624 #ifdef HAVE_TARGET_64_LITTLE
1626 class Track_relocs
<64, false>;
1629 #ifdef HAVE_TARGET_64_BIG
1631 class Track_relocs
<64, true>;
1634 } // End namespace gold.