1 // object.h -- support for an object file for linking in gold -*- C++ -*-
3 // Copyright 2006, 2007 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.
30 #include "elfcpp_file.h"
37 class General_options
;
43 class Object_merge_map
;
45 template<typename Stringpool_char
>
46 class Stringpool_template
;
48 // Data to pass from read_symbols() to add_symbols().
50 struct Read_symbols_data
53 File_view
* section_headers
;
55 File_view
* section_names
;
56 // Size of section name data in bytes.
57 section_size_type section_names_size
;
60 // Size of symbol data in bytes.
61 section_size_type symbols_size
;
62 // Offset of external symbols within symbol data. This structure
63 // sometimes contains only external symbols, in which case this will
64 // be zero. Sometimes it contains all symbols.
65 section_offset_type external_symbols_offset
;
67 File_view
* symbol_names
;
68 // Size of symbol name data in bytes.
69 section_size_type symbol_names_size
;
71 // Version information. This is only used on dynamic objects.
72 // Version symbol data (from SHT_GNU_versym section).
74 section_size_type versym_size
;
75 // Version definition data (from SHT_GNU_verdef section).
77 section_size_type verdef_size
;
78 unsigned int verdef_info
;
79 // Needed version data (from SHT_GNU_verneed section).
81 section_size_type verneed_size
;
82 unsigned int verneed_info
;
85 // Information used to print error messages.
87 struct Symbol_location_info
89 std::string source_file
;
90 std::string enclosing_symbol_name
;
94 // Data about a single relocation section. This is read in
95 // read_relocs and processed in scan_relocs.
99 // Index of reloc section.
100 unsigned int reloc_shndx
;
101 // Index of section that relocs apply to.
102 unsigned int data_shndx
;
103 // Contents of reloc section.
105 // Reloc section type.
106 unsigned int sh_type
;
107 // Number of reloc entries.
110 Output_section
* output_section
;
111 // Whether this section has special handling for offsets.
112 bool needs_special_offset_handling
;
115 // Relocations in an object file. This is read in read_relocs and
116 // processed in scan_relocs.
118 struct Read_relocs_data
120 typedef std::vector
<Section_relocs
> Relocs_list
;
123 // The local symbols.
124 File_view
* local_symbols
;
127 // Object is an abstract base class which represents either a 32-bit
128 // or a 64-bit input object. This can be a regular object file
129 // (ET_REL) or a shared object (ET_DYN).
134 // NAME is the name of the object as we would report it to the user
135 // (e.g., libfoo.a(bar.o) if this is in an archive. INPUT_FILE is
136 // used to read the file. OFFSET is the offset within the input
137 // file--0 for a .o or .so file, something else for a .a file.
138 Object(const std::string
& name
, Input_file
* input_file
, bool is_dynamic
,
140 : name_(name
), input_file_(input_file
), offset_(offset
), shnum_(-1U),
141 is_dynamic_(is_dynamic
), target_(NULL
)
147 // Return the name of the object as we would report it to the tuser.
150 { return this->name_
; }
152 // Get the offset into the file.
155 { return this->offset_
; }
157 // Return whether this is a dynamic object.
160 { return this->is_dynamic_
; }
162 // Return the target structure associated with this object.
165 { return this->target_
; }
167 // Lock the underlying file.
170 { this->input_file()->file().lock(t
); }
172 // Unlock the underlying file.
174 unlock(const Task
* t
)
175 { this->input_file()->file().unlock(t
); }
177 // Return whether the underlying file is locked.
180 { return this->input_file()->file().is_locked(); }
182 // Return the token, so that the task can be queued.
185 { return this->input_file()->file().token(); }
187 // Release the underlying file.
190 { this->input_file_
->file().release(); }
192 // Return the sized target structure associated with this object.
193 // This is like the target method but it returns a pointer of
194 // appropriate checked type.
195 template<int size
, bool big_endian
>
196 Sized_target
<size
, big_endian
>*
197 sized_target(ACCEPT_SIZE_ENDIAN_ONLY
) const;
199 // Get the number of sections.
202 { return this->shnum_
; }
204 // Return a view of the contents of a section. Set *PLEN to the
205 // size. CACHE is a hint as in File_read::get_view.
207 section_contents(unsigned int shndx
, section_size_type
* plen
, bool cache
);
209 // Return the name of a section given a section index. This is only
210 // used for error messages.
212 section_name(unsigned int shndx
)
213 { return this->do_section_name(shndx
); }
215 // Return the section flags given a section index.
217 section_flags(unsigned int shndx
)
218 { return this->do_section_flags(shndx
); }
220 // Return the section type given a section index.
222 section_type(unsigned int shndx
)
223 { return this->do_section_type(shndx
); }
225 // Return the section link field given a section index.
227 section_link(unsigned int shndx
)
228 { return this->do_section_link(shndx
); }
230 // Return the section info field given a section index.
232 section_info(unsigned int shndx
)
233 { return this->do_section_info(shndx
); }
235 // Read the symbol information.
237 read_symbols(Read_symbols_data
* sd
)
238 { return this->do_read_symbols(sd
); }
240 // Pass sections which should be included in the link to the Layout
241 // object, and record where the sections go in the output file.
243 layout(Symbol_table
* symtab
, Layout
* layout
, Read_symbols_data
* sd
)
244 { this->do_layout(symtab
, layout
, sd
); }
246 // Add symbol information to the global symbol table.
248 add_symbols(Symbol_table
* symtab
, Read_symbols_data
* sd
)
249 { this->do_add_symbols(symtab
, sd
); }
251 // Functions and types for the elfcpp::Elf_file interface. This
252 // permit us to use Object as the File template parameter for
255 // The View class is returned by view. It must support a single
256 // method, data(). This is trivial, because get_view does what we
261 View(const unsigned char* p
)
270 const unsigned char* p_
;
275 view(off_t file_offset
, section_size_type data_size
)
276 { return View(this->get_view(file_offset
, data_size
, true)); }
280 error(const char* format
, ...) const ATTRIBUTE_PRINTF_2
;
282 // A location in the file.
288 Location(off_t fo
, section_size_type ds
)
289 : file_offset(fo
), data_size(ds
)
293 // Get a View given a Location.
294 View
view(Location loc
)
295 { return View(this->get_view(loc
.file_offset
, loc
.data_size
, true)); }
298 // Read the symbols--implemented by child class.
300 do_read_symbols(Read_symbols_data
*) = 0;
302 // Lay out sections--implemented by child class.
304 do_layout(Symbol_table
*, Layout
*, Read_symbols_data
*) = 0;
306 // Add symbol information to the global symbol table--implemented by
309 do_add_symbols(Symbol_table
*, Read_symbols_data
*) = 0;
311 // Return the location of the contents of a section. Implemented by
314 do_section_contents(unsigned int shndx
) = 0;
316 // Get the name of a section--implemented by child class.
318 do_section_name(unsigned int shndx
) = 0;
320 // Get section flags--implemented by child class.
322 do_section_flags(unsigned int shndx
) = 0;
324 // Get section type--implemented by child class.
326 do_section_type(unsigned int shndx
) = 0;
328 // Get section link field--implemented by child class.
330 do_section_link(unsigned int shndx
) = 0;
332 // Get section info field--implemented by child class.
334 do_section_info(unsigned int shndx
) = 0;
336 // Get the file. We pass on const-ness.
339 { return this->input_file_
; }
343 { return this->input_file_
; }
345 // Get a view into the underlying file.
347 get_view(off_t start
, section_size_type size
, bool cache
)
349 return this->input_file()->file().get_view(start
+ this->offset_
, size
,
353 // Get a lasting view into the underlying file.
355 get_lasting_view(off_t start
, section_size_type size
, bool cache
)
357 return this->input_file()->file().get_lasting_view(start
+ this->offset_
,
361 // Read data from the underlying file.
363 read(off_t start
, section_size_type size
, void* p
) const
364 { this->input_file()->file().read(start
+ this->offset_
, size
, p
); }
368 set_target(int machine
, int size
, bool big_endian
, int osabi
,
371 // Set the number of sections.
374 { this->shnum_
= shnum
; }
376 // Functions used by both Sized_relobj and Sized_dynobj.
378 // Read the section data into a Read_symbols_data object.
379 template<int size
, bool big_endian
>
381 read_section_data(elfcpp::Elf_file
<size
, big_endian
, Object
>*,
384 // If NAME is the name of a special .gnu.warning section, arrange
385 // for the warning to be issued. SHNDX is the section index.
386 // Return whether it is a warning section.
388 handle_gnu_warning_section(const char* name
, unsigned int shndx
,
392 // This class may not be copied.
393 Object(const Object
&);
394 Object
& operator=(const Object
&);
396 // Name of object as printed to user.
398 // For reading the file.
399 Input_file
* input_file_
;
400 // Offset within the file--0 for an object file, non-0 for an
403 // Number of input sections.
405 // Whether this is a dynamic object.
407 // Target functions--may be NULL if the target is not known.
411 // Implement sized_target inline for efficiency. This approach breaks
412 // static type checking, but is made safe using asserts.
414 template<int size
, bool big_endian
>
415 inline Sized_target
<size
, big_endian
>*
416 Object::sized_target(ACCEPT_SIZE_ENDIAN_ONLY
) const
418 gold_assert(this->target_
->get_size() == size
);
419 gold_assert(this->target_
->is_big_endian() ? big_endian
: !big_endian
);
420 return static_cast<Sized_target
<size
, big_endian
>*>(this->target_
);
423 // A regular object (ET_REL). This is an abstract base class itself.
424 // The implementation is the template class Sized_relobj.
426 class Relobj
: public Object
429 Relobj(const std::string
& name
, Input_file
* input_file
, off_t offset
= 0)
430 : Object(name
, input_file
, false, offset
),
432 object_merge_map_(NULL
),
433 relocs_must_follow_section_writes_(false)
438 read_relocs(Read_relocs_data
* rd
)
439 { return this->do_read_relocs(rd
); }
441 // Scan the relocs and adjust the symbol table.
443 scan_relocs(const General_options
& options
, Symbol_table
* symtab
,
444 Layout
* layout
, Read_relocs_data
* rd
)
445 { return this->do_scan_relocs(options
, symtab
, layout
, rd
); }
447 // The number of local symbols in the input symbol table.
449 local_symbol_count() const
450 { return this->do_local_symbol_count(); }
452 // Initial local symbol processing: count the number of local symbols
453 // in the output symbol table and dynamic symbol table; add local symbol
454 // names to *POOL and *DYNPOOL.
456 count_local_symbols(Stringpool_template
<char>* pool
,
457 Stringpool_template
<char>* dynpool
)
458 { return this->do_count_local_symbols(pool
, dynpool
); }
460 // Set the values of the local symbols, set the output symbol table
461 // indexes for the local variables, and set the offset where local
462 // symbol information will be stored. Returns the new local symbol index.
464 finalize_local_symbols(unsigned int index
, off_t off
)
465 { return this->do_finalize_local_symbols(index
, off
); }
467 // Set the output dynamic symbol table indexes for the local variables.
469 set_local_dynsym_indexes(unsigned int index
)
470 { return this->do_set_local_dynsym_indexes(index
); }
472 // Set the offset where local dynamic symbol information will be stored.
474 set_local_dynsym_offset(off_t off
)
475 { return this->do_set_local_dynsym_offset(off
); }
477 // Relocate the input sections and write out the local symbols.
479 relocate(const General_options
& options
, const Symbol_table
* symtab
,
480 const Layout
* layout
, Output_file
* of
)
481 { return this->do_relocate(options
, symtab
, layout
, of
); }
483 // Return whether an input section is being included in the link.
485 is_section_included(unsigned int shndx
) const
487 gold_assert(shndx
< this->map_to_output_
.size());
488 return this->map_to_output_
[shndx
].output_section
!= NULL
;
491 // Return whether an input section requires special
492 // handling--whether it is not simply mapped from the input file to
495 is_section_specially_mapped(unsigned int shndx
) const
497 gold_assert(shndx
< this->map_to_output_
.size());
498 return (this->map_to_output_
[shndx
].output_section
!= NULL
499 && this->map_to_output_
[shndx
].offset
== -1);
502 // Given a section index, return the corresponding Output_section
503 // (which will be NULL if the section is not included in the link)
504 // and set *POFF to the offset within that section. *POFF will be
505 // set to -1 if the section requires special handling.
506 inline Output_section
*
507 output_section(unsigned int shndx
, section_offset_type
* poff
) const;
509 // Set the offset of an input section within its output section.
511 set_section_offset(unsigned int shndx
, section_offset_type off
)
513 gold_assert(shndx
< this->map_to_output_
.size());
514 this->map_to_output_
[shndx
].offset
= off
;
517 // Return true if we need to wait for output sections to be written
518 // before we can apply relocations. This is true if the object has
519 // any relocations for sections which require special handling, such
520 // as the exception frame section.
522 relocs_must_follow_section_writes() const
523 { return this->relocs_must_follow_section_writes_
; }
525 // Return the object merge map.
528 { return this->object_merge_map_
; }
530 // Set the object merge map.
532 set_merge_map(Object_merge_map
* object_merge_map
)
534 gold_assert(this->object_merge_map_
== NULL
);
535 this->object_merge_map_
= object_merge_map
;
539 // What we need to know to map an input section to an output
540 // section. We keep an array of these, one for each input section,
541 // indexed by the input section number.
544 // The output section. This is NULL if the input section is to be
546 Output_section
* output_section
;
547 // The offset within the output section. This is -1 if the
548 // section requires special handling.
549 section_offset_type offset
;
552 // Read the relocs--implemented by child class.
554 do_read_relocs(Read_relocs_data
*) = 0;
556 // Scan the relocs--implemented by child class.
558 do_scan_relocs(const General_options
&, Symbol_table
*, Layout
*,
559 Read_relocs_data
*) = 0;
561 // Return the number of local symbols--implemented by child class.
563 do_local_symbol_count() const = 0;
565 // Count local symbols--implemented by child class.
567 do_count_local_symbols(Stringpool_template
<char>*,
568 Stringpool_template
<char>*) = 0;
570 // Finalize the local symbols. Set the output symbol table indexes for the local variables, and set the
571 // offset where local symbol information will be stored.
573 do_finalize_local_symbols(unsigned int, off_t
) = 0;
575 // Set the output dynamic symbol table indexes for the local variables.
577 do_set_local_dynsym_indexes(unsigned int) = 0;
579 // Set the offset where local dynamic symbol information will be stored.
581 do_set_local_dynsym_offset(off_t
) = 0;
583 // Relocate the input sections and write out the local
584 // symbols--implemented by child class.
586 do_relocate(const General_options
& options
, const Symbol_table
* symtab
,
587 const Layout
*, Output_file
* of
) = 0;
589 // Return the vector mapping input sections to output sections.
590 std::vector
<Map_to_output
>&
592 { return this->map_to_output_
; }
594 const std::vector
<Map_to_output
>&
595 map_to_output() const
596 { return this->map_to_output_
; }
598 // Record that we must wait for the output sections to be written
599 // before applying relocations.
601 set_relocs_must_follow_section_writes()
602 { this->relocs_must_follow_section_writes_
= true; }
605 // Mapping from input sections to output section.
606 std::vector
<Map_to_output
> map_to_output_
;
607 // Mappings for merge sections. This is managed by the code in the
609 Object_merge_map
* object_merge_map_
;
610 // Whether we need to wait for output sections to be written before
611 // we can apply relocations.
612 bool relocs_must_follow_section_writes_
;
615 // Implement Object::output_section inline for efficiency.
616 inline Output_section
*
617 Relobj::output_section(unsigned int shndx
, section_offset_type
* poff
) const
619 gold_assert(shndx
< this->map_to_output_
.size());
620 const Map_to_output
& mo(this->map_to_output_
[shndx
]);
622 return mo
.output_section
;
625 // This class is used to handle relocations against a section symbol
626 // in an SHF_MERGE section. For such a symbol, we need to know the
627 // addend of the relocation before we can determine the final value.
628 // The addend gives us the location in the input section, and we can
629 // determine how it is mapped to the output section. For a
630 // non-section symbol, we apply the addend to the final value of the
631 // symbol; that is done in finalize_local_symbols, and does not use
635 class Merged_symbol_value
638 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Value
;
640 // We use a hash table to map offsets in the input section to output
642 typedef Unordered_map
<section_offset_type
, Value
> Output_addresses
;
644 Merged_symbol_value(Value input_value
, Value output_start_address
)
645 : input_value_(input_value
), output_start_address_(output_start_address
),
649 // Initialize the hash table.
651 initialize_input_to_output_map(const Relobj
*, unsigned int input_shndx
);
653 // Release the hash table to save space.
655 free_input_to_output_map()
656 { this->output_addresses_
.clear(); }
658 // Get the output value corresponding to an addend. The object and
659 // input section index are passed in because the caller will have
660 // them; otherwise we could store them here.
662 value(const Relobj
* object
, unsigned int input_shndx
, Value addend
) const
664 Value input_offset
= this->input_value_
+ addend
;
665 typename
Output_addresses::const_iterator p
=
666 this->output_addresses_
.find(input_offset
);
667 if (p
!= this->output_addresses_
.end())
670 return this->value_from_output_section(object
, input_shndx
, input_offset
);
674 // Get the output value for an input offset if we couldn't find it
675 // in the hash table.
677 value_from_output_section(const Relobj
*, unsigned int input_shndx
,
678 Value input_offset
) const;
680 // The value of the section symbol in the input file. This is
681 // normally zero, but could in principle be something else.
683 // The start address of this merged section in the output file.
684 Value output_start_address_
;
685 // A hash table which maps offsets in the input section to output
686 // addresses. This only maps specific offsets, not all offsets.
687 Output_addresses output_addresses_
;
690 // This POD class is holds the value of a symbol. This is used for
691 // local symbols, and for all symbols during relocation processing.
692 // For special sections, such as SHF_MERGE sections, this calls a
693 // function to get the final symbol value.
699 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Value
;
702 : output_symtab_index_(0), output_dynsym_index_(-1U), input_shndx_(0),
703 is_section_symbol_(false), is_tls_symbol_(false),
704 has_output_value_(true)
705 { this->u_
.value
= 0; }
707 // Get the value of this symbol. OBJECT is the object in which this
708 // symbol is defined, and ADDEND is an addend to add to the value.
709 template<bool big_endian
>
711 value(const Sized_relobj
<size
, big_endian
>* object
, Value addend
) const
713 if (this->has_output_value_
)
714 return this->u_
.value
+ addend
;
716 return this->u_
.merged_symbol_value
->value(object
, this->input_shndx_
,
720 // Set the value of this symbol in the output symbol table.
722 set_output_value(Value value
)
723 { this->u_
.value
= value
; }
725 // For a section symbol in a merged section, we need more
728 set_merged_symbol_value(Merged_symbol_value
<size
>* msv
)
730 gold_assert(this->is_section_symbol_
);
731 this->has_output_value_
= false;
732 this->u_
.merged_symbol_value
= msv
;
735 // Initialize the input to output map for a section symbol in a
736 // merged section. We also initialize the value of a non-section
737 // symbol in a merged section.
739 initialize_input_to_output_map(const Relobj
* object
)
741 if (!this->has_output_value_
)
743 gold_assert(this->is_section_symbol_
);
744 Merged_symbol_value
<size
>* msv
= this->u_
.merged_symbol_value
;
745 msv
->initialize_input_to_output_map(object
, this->input_shndx_
);
749 // Free the input to output map for a section symbol in a merged
752 free_input_to_output_map()
754 if (!this->has_output_value_
)
755 this->u_
.merged_symbol_value
->free_input_to_output_map();
758 // Set the value of the symbol from the input file. This is only
759 // called by count_local_symbols, to communicate the value to
760 // finalize_local_symbols.
762 set_input_value(Value value
)
763 { this->u_
.value
= value
; }
765 // Return the input value. This is only called by
766 // finalize_local_symbols.
769 { return this->u_
.value
; }
771 // Return whether this symbol should go into the output symbol
774 needs_output_symtab_entry() const
775 { return this->output_symtab_index_
!= -1U; }
777 // Return the index in the output symbol table.
779 output_symtab_index() const
781 gold_assert(this->output_symtab_index_
!= 0);
782 return this->output_symtab_index_
;
785 // Set the index in the output symbol table.
787 set_output_symtab_index(unsigned int i
)
789 gold_assert(this->output_symtab_index_
== 0);
790 this->output_symtab_index_
= i
;
793 // Record that this symbol should not go into the output symbol
796 set_no_output_symtab_entry()
798 gold_assert(this->output_symtab_index_
== 0);
799 this->output_symtab_index_
= -1U;
802 // Set the index in the output dynamic symbol table.
804 set_needs_output_dynsym_entry()
806 this->output_dynsym_index_
= 0;
809 // Return whether this symbol should go into the output symbol
812 needs_output_dynsym_entry() const
814 return this->output_dynsym_index_
!= -1U;
817 // Record that this symbol should go into the dynamic symbol table.
819 set_output_dynsym_index(unsigned int i
)
821 gold_assert(this->output_dynsym_index_
== 0);
822 this->output_dynsym_index_
= i
;
825 // Return the index in the output dynamic symbol table.
827 output_dynsym_index() const
829 gold_assert(this->output_dynsym_index_
!= 0);
830 return this->output_dynsym_index_
;
833 // Set the index of the input section in the input file.
835 set_input_shndx(unsigned int i
)
837 this->input_shndx_
= i
;
838 // input_shndx_ field is a bitfield, so make sure that the value
840 gold_assert(this->input_shndx_
== i
);
843 // Return the index of the input section in the input file.
846 { return this->input_shndx_
; }
848 // Whether this is a section symbol.
850 is_section_symbol() const
851 { return this->is_section_symbol_
; }
853 // Record that this is a section symbol.
855 set_is_section_symbol()
856 { this->is_section_symbol_
= true; }
858 // Record that this is a TLS symbol.
861 { this->is_tls_symbol_
= true; }
863 // Return TRUE if this is a TLS symbol.
865 is_tls_symbol() const
866 { return this->is_tls_symbol_
; }
869 // The index of this local symbol in the output symbol table. This
870 // will be -1 if the symbol should not go into the symbol table.
871 unsigned int output_symtab_index_
;
872 // The index of this local symbol in the dynamic symbol table. This
873 // will be -1 if the symbol should not go into the symbol table.
874 unsigned int output_dynsym_index_
;
875 // The section index in the input file in which this symbol is
877 unsigned int input_shndx_
: 29;
878 // Whether this is a STT_SECTION symbol.
879 bool is_section_symbol_
: 1;
880 // Whether this is a STT_TLS symbol.
881 bool is_tls_symbol_
: 1;
882 // Whether this symbol has a value for the output file. This is
883 // normally set to true during Layout::finalize, by
884 // finalize_local_symbols. It will be false for a section symbol in
885 // a merge section, as for such symbols we can not determine the
886 // value to use in a relocation until we see the addend.
887 bool has_output_value_
: 1;
890 // This is used if has_output_value_ is true. Between
891 // count_local_symbols and finalize_local_symbols, this is the
892 // value in the input file. After finalize_local_symbols, it is
893 // the value in the output file.
895 // This is used if has_output_value_ is false. It points to the
896 // information we need to get the value for a merge section.
897 Merged_symbol_value
<size
>* merged_symbol_value
;
901 // A regular object file. This is size and endian specific.
903 template<int size
, bool big_endian
>
904 class Sized_relobj
: public Relobj
907 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Address
;
908 typedef std::vector
<Symbol
*> Symbols
;
909 typedef std::vector
<Symbol_value
<size
> > Local_values
;
911 Sized_relobj(const std::string
& name
, Input_file
* input_file
, off_t offset
,
912 const typename
elfcpp::Ehdr
<size
, big_endian
>&);
916 // Set up the object file based on the ELF header.
918 setup(const typename
elfcpp::Ehdr
<size
, big_endian
>&);
920 // If SYM is the index of a global symbol in the object file's
921 // symbol table, return the Symbol object. Otherwise, return NULL.
923 global_symbol(unsigned int sym
) const
925 if (sym
>= this->local_symbol_count_
)
927 gold_assert(sym
- this->local_symbol_count_
< this->symbols_
.size());
928 return this->symbols_
[sym
- this->local_symbol_count_
];
933 // Return the section index of symbol SYM. Set *VALUE to its value
934 // in the object file. Note that for a symbol which is not defined
935 // in this object file, this will set *VALUE to 0 and return
936 // SHN_UNDEF; it will not return the final value of the symbol in
939 symbol_section_and_value(unsigned int sym
, Address
* value
);
941 // Return a pointer to the Symbol_value structure which holds the
942 // value of a local symbol.
943 const Symbol_value
<size
>*
944 local_symbol(unsigned int sym
) const
946 gold_assert(sym
< this->local_values_
.size());
947 return &this->local_values_
[sym
];
950 // Return the index of local symbol SYM in the ordinary symbol
951 // table. A value of -1U means that the symbol is not being output.
953 symtab_index(unsigned int sym
) const
955 gold_assert(sym
< this->local_values_
.size());
956 return this->local_values_
[sym
].output_symtab_index();
959 // Return the index of local symbol SYM in the dynamic symbol
960 // table. A value of -1U means that the symbol is not being output.
962 dynsym_index(unsigned int sym
) const
964 gold_assert(sym
< this->local_values_
.size());
965 return this->local_values_
[sym
].output_dynsym_index();
968 // Return the appropriate Sized_target structure.
969 Sized_target
<size
, big_endian
>*
972 return this->Object::sized_target
973 SELECT_SIZE_ENDIAN_NAME(size
, big_endian
) (
974 SELECT_SIZE_ENDIAN_ONLY(size
, big_endian
));
977 // Return the value of the local symbol symndx.
979 local_symbol_value(unsigned int symndx
) const;
982 set_needs_output_dynsym_entry(unsigned int sym
)
984 gold_assert(sym
< this->local_values_
.size());
985 this->local_values_
[sym
].set_needs_output_dynsym_entry();
988 // Return whether the local symbol SYMNDX has a GOT offset.
989 // For TLS symbols, the GOT entry will hold its tp-relative offset.
991 local_has_got_offset(unsigned int symndx
) const
993 return (this->local_got_offsets_
.find(symndx
)
994 != this->local_got_offsets_
.end());
997 // Return the GOT offset of the local symbol SYMNDX.
999 local_got_offset(unsigned int symndx
) const
1001 Local_got_offsets::const_iterator p
=
1002 this->local_got_offsets_
.find(symndx
);
1003 gold_assert(p
!= this->local_got_offsets_
.end());
1007 // Set the GOT offset of the local symbol SYMNDX to GOT_OFFSET.
1009 set_local_got_offset(unsigned int symndx
, unsigned int got_offset
)
1011 std::pair
<Local_got_offsets::iterator
, bool> ins
=
1012 this->local_got_offsets_
.insert(std::make_pair(symndx
, got_offset
));
1013 gold_assert(ins
.second
);
1016 // Return whether the local TLS symbol SYMNDX has a GOT offset.
1017 // The GOT entry at this offset will contain a module index. If
1018 // NEED_PAIR is true, a second entry immediately following the first
1019 // will contain the dtv-relative offset.
1021 local_has_tls_got_offset(unsigned int symndx
, bool need_pair
) const
1023 typename
Local_tls_got_offsets::const_iterator p
=
1024 this->local_tls_got_offsets_
.find(symndx
);
1025 if (p
== this->local_tls_got_offsets_
.end()
1026 || (need_pair
&& !p
->second
.have_pair_
))
1031 // Return the offset of the GOT entry for the local TLS symbol SYMNDX.
1032 // If NEED_PAIR is true, we need the offset of a pair of GOT entries;
1033 // otherwise we need the offset of the GOT entry for the module index.
1035 local_tls_got_offset(unsigned int symndx
, bool need_pair
) const
1037 typename
Local_tls_got_offsets::const_iterator p
=
1038 this->local_tls_got_offsets_
.find(symndx
);
1039 gold_assert(p
!= this->local_tls_got_offsets_
.end());
1040 gold_assert(!need_pair
|| p
->second
.have_pair_
);
1041 return p
->second
.got_offset_
;
1044 // Set the offset of the GOT entry for the local TLS symbol SYMNDX
1045 // to GOT_OFFSET. If HAVE_PAIR is true, we have a pair of GOT entries;
1046 // otherwise, we have just a single entry for the module index.
1048 set_local_tls_got_offset(unsigned int symndx
, unsigned int got_offset
,
1051 typename
Local_tls_got_offsets::iterator p
=
1052 this->local_tls_got_offsets_
.find(symndx
);
1053 if (p
!= this->local_tls_got_offsets_
.end())
1055 // An entry already existed for this symbol. This can happen
1056 // if we see a relocation asking for the module index before
1057 // a relocation asking for the pair. In that case, the original
1058 // GOT entry will remain, but won't get used by any further
1060 p
->second
.got_offset_
= got_offset
;
1061 gold_assert(have_pair
);
1062 p
->second
.have_pair_
= true;
1066 std::pair
<typename
Local_tls_got_offsets::iterator
, bool> ins
=
1067 this->local_tls_got_offsets_
.insert(
1068 std::make_pair(symndx
, Tls_got_entry(got_offset
, have_pair
)));
1069 gold_assert(ins
.second
);
1073 // Return the name of the symbol that spans the given offset in the
1074 // specified section in this object. This is used only for error
1075 // messages and is not particularly efficient.
1077 get_symbol_location_info(unsigned int shndx
, off_t offset
,
1078 Symbol_location_info
* info
);
1081 // Read the symbols.
1083 do_read_symbols(Read_symbols_data
*);
1085 // Return the number of local symbols.
1087 do_local_symbol_count() const
1088 { return this->local_symbol_count_
; }
1090 // Lay out the input sections.
1092 do_layout(Symbol_table
*, Layout
*, Read_symbols_data
*);
1094 // Add the symbols to the symbol table.
1096 do_add_symbols(Symbol_table
*, Read_symbols_data
*);
1100 do_read_relocs(Read_relocs_data
*);
1102 // Scan the relocs and adjust the symbol table.
1104 do_scan_relocs(const General_options
&, Symbol_table
*, Layout
*,
1107 // Count the local symbols.
1109 do_count_local_symbols(Stringpool_template
<char>*,
1110 Stringpool_template
<char>*);
1112 // Finalize the local symbols.
1114 do_finalize_local_symbols(unsigned int, off_t
);
1116 // Set the offset where local dynamic symbol information will be stored.
1118 do_set_local_dynsym_indexes(unsigned int);
1120 // Set the offset where local dynamic symbol information will be stored.
1122 do_set_local_dynsym_offset(off_t
);
1124 // Relocate the input sections and write out the local symbols.
1126 do_relocate(const General_options
& options
, const Symbol_table
* symtab
,
1127 const Layout
*, Output_file
* of
);
1129 // Get the name of a section.
1131 do_section_name(unsigned int shndx
)
1132 { return this->elf_file_
.section_name(shndx
); }
1134 // Return the location of the contents of a section.
1136 do_section_contents(unsigned int shndx
)
1137 { return this->elf_file_
.section_contents(shndx
); }
1139 // Return section flags.
1141 do_section_flags(unsigned int shndx
)
1142 { return this->elf_file_
.section_flags(shndx
); }
1144 // Return section type.
1146 do_section_type(unsigned int shndx
)
1147 { return this->elf_file_
.section_type(shndx
); }
1149 // Return the section link field.
1151 do_section_link(unsigned int shndx
)
1152 { return this->elf_file_
.section_link(shndx
); }
1154 // Return the section info field.
1156 do_section_info(unsigned int shndx
)
1157 { return this->elf_file_
.section_info(shndx
); }
1161 typedef Sized_relobj
<size
, big_endian
> This
;
1162 static const int ehdr_size
= elfcpp::Elf_sizes
<size
>::ehdr_size
;
1163 static const int shdr_size
= elfcpp::Elf_sizes
<size
>::shdr_size
;
1164 static const int sym_size
= elfcpp::Elf_sizes
<size
>::sym_size
;
1165 typedef elfcpp::Shdr
<size
, big_endian
> Shdr
;
1167 // Find the SHT_SYMTAB section, given the section headers.
1169 find_symtab(const unsigned char* pshdrs
);
1171 // Return whether SHDR has the right flags for a GNU style exception
1174 check_eh_frame_flags(const elfcpp::Shdr
<size
, big_endian
>* shdr
) const;
1176 // Return whether there is a section named .eh_frame which might be
1177 // a GNU style exception frame section.
1179 find_eh_frame(const unsigned char* pshdrs
, const char* names
,
1180 section_size_type names_size
) const;
1182 // Whether to include a section group in the link.
1184 include_section_group(Layout
*, unsigned int,
1185 const elfcpp::Shdr
<size
, big_endian
>&,
1186 std::vector
<bool>*);
1188 // Whether to include a linkonce section in the link.
1190 include_linkonce_section(Layout
*, const char*,
1191 const elfcpp::Shdr
<size
, big_endian
>&);
1193 // Views and sizes when relocating.
1196 unsigned char* view
;
1197 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
;
1199 section_size_type view_size
;
1200 bool is_input_output_view
;
1201 bool is_postprocessing_view
;
1204 typedef std::vector
<View_size
> Views
;
1206 // Write section data to the output file. Record the views and
1207 // sizes in VIEWS for use when relocating.
1209 write_sections(const unsigned char* pshdrs
, Output_file
*, Views
*) const;
1211 // Relocate the sections in the output file.
1213 relocate_sections(const General_options
& options
, const Symbol_table
*,
1214 const Layout
*, const unsigned char* pshdrs
, Views
*);
1216 // Initialize input to output maps for section symbols in merged
1219 initialize_input_to_output_maps();
1221 // Free the input to output maps for section symbols in merged
1224 free_input_to_output_maps();
1226 // Write out the local symbols.
1228 write_local_symbols(Output_file
*,
1229 const Stringpool_template
<char>*,
1230 const Stringpool_template
<char>*);
1232 // The GOT offsets of local symbols. This map also stores GOT offsets
1233 // for tp-relative offsets for TLS symbols.
1234 typedef Unordered_map
<unsigned int, unsigned int> Local_got_offsets
;
1236 // The TLS GOT offsets of local symbols. The map stores the offsets
1237 // for either a single GOT entry that holds the module index of a TLS
1238 // symbol, or a pair of GOT entries containing the module index and
1239 // dtv-relative offset.
1240 struct Tls_got_entry
1242 Tls_got_entry(int got_offset
, bool have_pair
)
1243 : got_offset_(got_offset
),
1244 have_pair_(have_pair
)
1249 typedef Unordered_map
<unsigned int, Tls_got_entry
> Local_tls_got_offsets
;
1251 // General access to the ELF file.
1252 elfcpp::Elf_file
<size
, big_endian
, Object
> elf_file_
;
1253 // Index of SHT_SYMTAB section.
1254 unsigned int symtab_shndx_
;
1255 // The number of local symbols.
1256 unsigned int local_symbol_count_
;
1257 // The number of local symbols which go into the output file.
1258 unsigned int output_local_symbol_count_
;
1259 // The number of local symbols which go into the output file's dynamic
1261 unsigned int output_local_dynsym_count_
;
1262 // The entries in the symbol table for the external symbols.
1264 // File offset for local symbols.
1265 off_t local_symbol_offset_
;
1266 // File offset for local dynamic symbols.
1267 off_t local_dynsym_offset_
;
1268 // Values of local symbols.
1269 Local_values local_values_
;
1270 // GOT offsets for local non-TLS symbols, and tp-relative offsets
1271 // for TLS symbols, indexed by symbol number.
1272 Local_got_offsets local_got_offsets_
;
1273 // GOT offsets for local TLS symbols, indexed by symbol number
1274 // and GOT entry type.
1275 Local_tls_got_offsets local_tls_got_offsets_
;
1276 // Whether this object has a GNU style .eh_frame section.
1280 // A class to manage the list of all objects.
1286 : relobj_list_(), dynobj_list_(), target_(NULL
), sonames_(),
1287 system_library_directory_()
1290 // The type of the list of input relocateable objects.
1291 typedef std::vector
<Relobj
*> Relobj_list
;
1292 typedef Relobj_list::const_iterator Relobj_iterator
;
1294 // The type of the list of input dynamic objects.
1295 typedef std::vector
<Dynobj
*> Dynobj_list
;
1296 typedef Dynobj_list::const_iterator Dynobj_iterator
;
1298 // Add an object to the list. Return true if all is well, or false
1299 // if this object should be ignored.
1301 add_object(Object
*);
1303 // Get the target we should use for the output file.
1306 { return this->target_
; }
1308 // For each dynamic object, check whether we've seen all of its
1309 // explicit dependencies.
1311 check_dynamic_dependencies() const;
1313 // Return whether an object was found in the system library
1316 found_in_system_library_directory(const Object
*) const;
1318 // Iterate over all regular objects.
1321 relobj_begin() const
1322 { return this->relobj_list_
.begin(); }
1326 { return this->relobj_list_
.end(); }
1328 // Iterate over all dynamic objects.
1331 dynobj_begin() const
1332 { return this->dynobj_list_
.begin(); }
1336 { return this->dynobj_list_
.end(); }
1338 // Return whether we have seen any dynamic objects.
1341 { return !this->dynobj_list_
.empty(); }
1343 // Return the number of input objects.
1345 number_of_input_objects() const
1346 { return this->relobj_list_
.size() + this->dynobj_list_
.size(); }
1349 Input_objects(const Input_objects
&);
1350 Input_objects
& operator=(const Input_objects
&);
1352 // The list of ordinary objects included in the link.
1353 Relobj_list relobj_list_
;
1354 // The list of dynamic objects included in the link.
1355 Dynobj_list dynobj_list_
;
1358 // SONAMEs that we have seen.
1359 Unordered_set
<std::string
> sonames_
;
1360 // The directory in which we find the libc.so.
1361 std::string system_library_directory_
;
1364 // Some of the information we pass to the relocation routines. We
1365 // group this together to avoid passing a dozen different arguments.
1367 template<int size
, bool big_endian
>
1368 struct Relocate_info
1370 // Command line options.
1371 const General_options
* options
;
1373 const Symbol_table
* symtab
;
1375 const Layout
* layout
;
1376 // Object being relocated.
1377 Sized_relobj
<size
, big_endian
>* object
;
1378 // Section index of relocation section.
1379 unsigned int reloc_shndx
;
1380 // Section index of section being relocated.
1381 unsigned int data_shndx
;
1383 // Return a string showing the location of a relocation. This is
1384 // only used for error messages.
1386 location(size_t relnum
, off_t reloffset
) const;
1389 // Return an Object appropriate for the input file. P is BYTES long,
1390 // and holds the ELF header.
1393 make_elf_object(const std::string
& name
, Input_file
*,
1394 off_t offset
, const unsigned char* p
,
1395 section_offset_type bytes
);
1397 } // end namespace gold
1399 #endif // !defined(GOLD_OBJECT_H)