1 // object.h -- support for an object file for linking in gold -*- C++ -*-
3 // Copyright 2006, 2007, 2008 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
;
44 class Relocatable_relocs
;
46 template<typename Stringpool_char
>
47 class Stringpool_template
;
49 // Data to pass from read_symbols() to add_symbols().
51 struct Read_symbols_data
54 File_view
* section_headers
;
56 File_view
* section_names
;
57 // Size of section name data in bytes.
58 section_size_type section_names_size
;
61 // Size of symbol data in bytes.
62 section_size_type symbols_size
;
63 // Offset of external symbols within symbol data. This structure
64 // sometimes contains only external symbols, in which case this will
65 // be zero. Sometimes it contains all symbols.
66 section_offset_type external_symbols_offset
;
68 File_view
* symbol_names
;
69 // Size of symbol name data in bytes.
70 section_size_type symbol_names_size
;
72 // Version information. This is only used on dynamic objects.
73 // Version symbol data (from SHT_GNU_versym section).
75 section_size_type versym_size
;
76 // Version definition data (from SHT_GNU_verdef section).
78 section_size_type verdef_size
;
79 unsigned int verdef_info
;
80 // Needed version data (from SHT_GNU_verneed section).
82 section_size_type verneed_size
;
83 unsigned int verneed_info
;
86 // Information used to print error messages.
88 struct Symbol_location_info
90 std::string source_file
;
91 std::string enclosing_symbol_name
;
95 // Data about a single relocation section. This is read in
96 // read_relocs and processed in scan_relocs.
100 // Index of reloc section.
101 unsigned int reloc_shndx
;
102 // Index of section that relocs apply to.
103 unsigned int data_shndx
;
104 // Contents of reloc section.
106 // Reloc section type.
107 unsigned int sh_type
;
108 // Number of reloc entries.
111 Output_section
* output_section
;
112 // Whether this section has special handling for offsets.
113 bool needs_special_offset_handling
;
114 // Whether the data section is allocated (has the SHF_ALLOC flag set).
115 bool is_data_section_allocated
;
118 // Relocations in an object file. This is read in read_relocs and
119 // processed in scan_relocs.
121 struct Read_relocs_data
123 typedef std::vector
<Section_relocs
> Relocs_list
;
126 // The local symbols.
127 File_view
* local_symbols
;
130 // Object is an abstract base class which represents either a 32-bit
131 // or a 64-bit input object. This can be a regular object file
132 // (ET_REL) or a shared object (ET_DYN).
137 // NAME is the name of the object as we would report it to the user
138 // (e.g., libfoo.a(bar.o) if this is in an archive. INPUT_FILE is
139 // used to read the file. OFFSET is the offset within the input
140 // file--0 for a .o or .so file, something else for a .a file.
141 Object(const std::string
& name
, Input_file
* input_file
, bool is_dynamic
,
143 : name_(name
), input_file_(input_file
), offset_(offset
), shnum_(-1U),
144 is_dynamic_(is_dynamic
), target_(NULL
)
145 { input_file
->file().add_object(); }
148 { this->input_file_
->file().remove_object(); }
150 // Return the name of the object as we would report it to the tuser.
153 { return this->name_
; }
155 // Get the offset into the file.
158 { return this->offset_
; }
160 // Return whether this is a dynamic object.
163 { return this->is_dynamic_
; }
165 // Return the target structure associated with this object.
168 { return this->target_
; }
170 // Lock the underlying file.
173 { this->input_file()->file().lock(t
); }
175 // Unlock the underlying file.
177 unlock(const Task
* t
)
178 { this->input_file()->file().unlock(t
); }
180 // Return whether the underlying file is locked.
183 { return this->input_file()->file().is_locked(); }
185 // Return the token, so that the task can be queued.
188 { return this->input_file()->file().token(); }
190 // Release the underlying file.
193 { this->input_file_
->file().release(); }
195 // Return whether we should just read symbols from this file.
198 { return this->input_file()->just_symbols(); }
200 // Return the sized target structure associated with this object.
201 // This is like the target method but it returns a pointer of
202 // appropriate checked type.
203 template<int size
, bool big_endian
>
204 Sized_target
<size
, big_endian
>*
205 sized_target() const;
207 // Get the number of sections.
210 { return this->shnum_
; }
212 // Return a view of the contents of a section. Set *PLEN to the
213 // size. CACHE is a hint as in File_read::get_view.
215 section_contents(unsigned int shndx
, section_size_type
* plen
, bool cache
);
217 // Return the size of a section given a section index.
219 section_size(unsigned int shndx
)
220 { return this->do_section_size(shndx
); }
222 // Return the name of a section given a section index.
224 section_name(unsigned int shndx
)
225 { return this->do_section_name(shndx
); }
227 // Return the section flags given a section index.
229 section_flags(unsigned int shndx
)
230 { return this->do_section_flags(shndx
); }
232 // Return the section address given a section index.
234 section_address(unsigned int shndx
)
235 { return this->do_section_address(shndx
); }
237 // Return the section type given a section index.
239 section_type(unsigned int shndx
)
240 { return this->do_section_type(shndx
); }
242 // Return the section link field given a section index.
244 section_link(unsigned int shndx
)
245 { return this->do_section_link(shndx
); }
247 // Return the section info field given a section index.
249 section_info(unsigned int shndx
)
250 { return this->do_section_info(shndx
); }
252 // Return the required section alignment given a section index.
254 section_addralign(unsigned int shndx
)
255 { return this->do_section_addralign(shndx
); }
257 // Read the symbol information.
259 read_symbols(Read_symbols_data
* sd
)
260 { return this->do_read_symbols(sd
); }
262 // Pass sections which should be included in the link to the Layout
263 // object, and record where the sections go in the output file.
265 layout(Symbol_table
* symtab
, Layout
* layout
, Read_symbols_data
* sd
)
266 { this->do_layout(symtab
, layout
, sd
); }
268 // Add symbol information to the global symbol table.
270 add_symbols(Symbol_table
* symtab
, Read_symbols_data
* sd
)
271 { this->do_add_symbols(symtab
, sd
); }
273 // Functions and types for the elfcpp::Elf_file interface. This
274 // permit us to use Object as the File template parameter for
277 // The View class is returned by view. It must support a single
278 // method, data(). This is trivial, because get_view does what we
283 View(const unsigned char* p
)
292 const unsigned char* p_
;
297 view(off_t file_offset
, section_size_type data_size
)
298 { return View(this->get_view(file_offset
, data_size
, true, true)); }
302 error(const char* format
, ...) const ATTRIBUTE_PRINTF_2
;
304 // A location in the file.
310 Location(off_t fo
, section_size_type ds
)
311 : file_offset(fo
), data_size(ds
)
315 // Get a View given a Location.
316 View
view(Location loc
)
317 { return View(this->get_view(loc
.file_offset
, loc
.data_size
, true, true)); }
319 // Get a view into the underlying file.
321 get_view(off_t start
, section_size_type size
, bool aligned
, bool cache
)
323 return this->input_file()->file().get_view(this->offset_
, start
, size
,
327 // Get a lasting view into the underlying file.
329 get_lasting_view(off_t start
, section_size_type size
, bool aligned
,
332 return this->input_file()->file().get_lasting_view(this->offset_
, start
,
333 size
, aligned
, cache
);
336 // Read data from the underlying file.
338 read(off_t start
, section_size_type size
, void* p
) const
339 { this->input_file()->file().read(start
+ this->offset_
, size
, p
); }
341 // Read multiple data from the underlying file.
343 read_multiple(const File_read::Read_multiple
& rm
)
344 { this->input_file()->file().read_multiple(this->offset_
, rm
); }
346 // Stop caching views in the underlying file.
348 clear_view_cache_marks()
349 { this->input_file()->file().clear_view_cache_marks(); }
352 // Read the symbols--implemented by child class.
354 do_read_symbols(Read_symbols_data
*) = 0;
356 // Lay out sections--implemented by child class.
358 do_layout(Symbol_table
*, Layout
*, Read_symbols_data
*) = 0;
360 // Add symbol information to the global symbol table--implemented by
363 do_add_symbols(Symbol_table
*, Read_symbols_data
*) = 0;
365 // Return the location of the contents of a section. Implemented by
368 do_section_contents(unsigned int shndx
) = 0;
370 // Get the size of a section--implemented by child class.
372 do_section_size(unsigned int shndx
) = 0;
374 // Get the name of a section--implemented by child class.
376 do_section_name(unsigned int shndx
) = 0;
378 // Get section flags--implemented by child class.
380 do_section_flags(unsigned int shndx
) = 0;
382 // Get section address--implemented by child class.
384 do_section_address(unsigned int shndx
) = 0;
386 // Get section type--implemented by child class.
388 do_section_type(unsigned int shndx
) = 0;
390 // Get section link field--implemented by child class.
392 do_section_link(unsigned int shndx
) = 0;
394 // Get section info field--implemented by child class.
396 do_section_info(unsigned int shndx
) = 0;
398 // Get section alignment--implemented by child class.
400 do_section_addralign(unsigned int shndx
) = 0;
402 // Get the file. We pass on const-ness.
405 { return this->input_file_
; }
409 { return this->input_file_
; }
413 set_target(int machine
, int size
, bool big_endian
, int osabi
,
416 // Set the number of sections.
419 { this->shnum_
= shnum
; }
421 // Functions used by both Sized_relobj and Sized_dynobj.
423 // Read the section data into a Read_symbols_data object.
424 template<int size
, bool big_endian
>
426 read_section_data(elfcpp::Elf_file
<size
, big_endian
, Object
>*,
429 // If NAME is the name of a special .gnu.warning section, arrange
430 // for the warning to be issued. SHNDX is the section index.
431 // Return whether it is a warning section.
433 handle_gnu_warning_section(const char* name
, unsigned int shndx
,
437 // This class may not be copied.
438 Object(const Object
&);
439 Object
& operator=(const Object
&);
441 // Name of object as printed to user.
443 // For reading the file.
444 Input_file
* input_file_
;
445 // Offset within the file--0 for an object file, non-0 for an
448 // Number of input sections.
450 // Whether this is a dynamic object.
452 // Target functions--may be NULL if the target is not known.
456 // Implement sized_target inline for efficiency. This approach breaks
457 // static type checking, but is made safe using asserts.
459 template<int size
, bool big_endian
>
460 inline Sized_target
<size
, big_endian
>*
461 Object::sized_target() const
463 gold_assert(this->target_
->get_size() == size
);
464 gold_assert(this->target_
->is_big_endian() ? big_endian
: !big_endian
);
465 return static_cast<Sized_target
<size
, big_endian
>*>(this->target_
);
468 // A regular object (ET_REL). This is an abstract base class itself.
469 // The implementation is the template class Sized_relobj.
471 class Relobj
: public Object
474 Relobj(const std::string
& name
, Input_file
* input_file
, off_t offset
= 0)
475 : Object(name
, input_file
, false, offset
),
477 map_to_relocatable_relocs_(NULL
),
478 object_merge_map_(NULL
),
479 relocs_must_follow_section_writes_(false)
484 read_relocs(Read_relocs_data
* rd
)
485 { return this->do_read_relocs(rd
); }
487 // Scan the relocs and adjust the symbol table.
489 scan_relocs(const General_options
& options
, Symbol_table
* symtab
,
490 Layout
* layout
, Read_relocs_data
* rd
)
491 { return this->do_scan_relocs(options
, symtab
, layout
, rd
); }
493 // The number of local symbols in the input symbol table.
495 local_symbol_count() const
496 { return this->do_local_symbol_count(); }
498 // Initial local symbol processing: count the number of local symbols
499 // in the output symbol table and dynamic symbol table; add local symbol
500 // names to *POOL and *DYNPOOL.
502 count_local_symbols(Stringpool_template
<char>* pool
,
503 Stringpool_template
<char>* dynpool
)
504 { return this->do_count_local_symbols(pool
, dynpool
); }
506 // Set the values of the local symbols, set the output symbol table
507 // indexes for the local variables, and set the offset where local
508 // symbol information will be stored. Returns the new local symbol index.
510 finalize_local_symbols(unsigned int index
, off_t off
)
511 { return this->do_finalize_local_symbols(index
, off
); }
513 // Set the output dynamic symbol table indexes for the local variables.
515 set_local_dynsym_indexes(unsigned int index
)
516 { return this->do_set_local_dynsym_indexes(index
); }
518 // Set the offset where local dynamic symbol information will be stored.
520 set_local_dynsym_offset(off_t off
)
521 { return this->do_set_local_dynsym_offset(off
); }
523 // Relocate the input sections and write out the local symbols.
525 relocate(const General_options
& options
, const Symbol_table
* symtab
,
526 const Layout
* layout
, Output_file
* of
)
527 { return this->do_relocate(options
, symtab
, layout
, of
); }
529 // Return whether an input section is being included in the link.
531 is_section_included(unsigned int shndx
) const
533 gold_assert(shndx
< this->map_to_output_
.size());
534 return this->map_to_output_
[shndx
].output_section
!= NULL
;
537 // Return whether an input section requires special
538 // handling--whether it is not simply mapped from the input file to
541 is_section_specially_mapped(unsigned int shndx
) const
543 gold_assert(shndx
< this->map_to_output_
.size());
544 return (this->map_to_output_
[shndx
].output_section
!= NULL
545 && this->map_to_output_
[shndx
].offset
== -1);
548 // Given a section index, return the corresponding Output_section
549 // (which will be NULL if the section is not included in the link)
550 // and set *POFF to the offset within that section. *POFF will be
551 // set to -1 if the section requires special handling.
552 inline Output_section
*
553 output_section(unsigned int shndx
, section_offset_type
* poff
) const;
555 // Set the offset of an input section within its output section.
557 set_section_offset(unsigned int shndx
, section_offset_type off
)
559 gold_assert(shndx
< this->map_to_output_
.size());
560 this->map_to_output_
[shndx
].offset
= off
;
563 // Return true if we need to wait for output sections to be written
564 // before we can apply relocations. This is true if the object has
565 // any relocations for sections which require special handling, such
566 // as the exception frame section.
568 relocs_must_follow_section_writes() const
569 { return this->relocs_must_follow_section_writes_
; }
571 // Return the object merge map.
574 { return this->object_merge_map_
; }
576 // Set the object merge map.
578 set_merge_map(Object_merge_map
* object_merge_map
)
580 gold_assert(this->object_merge_map_
== NULL
);
581 this->object_merge_map_
= object_merge_map
;
584 // Record the relocatable reloc info for an input reloc section.
586 set_relocatable_relocs(unsigned int reloc_shndx
, Relocatable_relocs
* rr
)
588 gold_assert(reloc_shndx
< this->shnum());
589 (*this->map_to_relocatable_relocs_
)[reloc_shndx
] = rr
;
592 // Get the relocatable reloc info for an input reloc section.
594 relocatable_relocs(unsigned int reloc_shndx
)
596 gold_assert(reloc_shndx
< this->shnum());
597 return (*this->map_to_relocatable_relocs_
)[reloc_shndx
];
601 // What we need to know to map an input section to an output
602 // section. We keep an array of these, one for each input section,
603 // indexed by the input section number.
606 // The output section. This is NULL if the input section is to be
608 Output_section
* output_section
;
609 // The offset within the output section. This is -1 if the
610 // section requires special handling.
611 section_offset_type offset
;
614 // Read the relocs--implemented by child class.
616 do_read_relocs(Read_relocs_data
*) = 0;
618 // Scan the relocs--implemented by child class.
620 do_scan_relocs(const General_options
&, Symbol_table
*, Layout
*,
621 Read_relocs_data
*) = 0;
623 // Return the number of local symbols--implemented by child class.
625 do_local_symbol_count() const = 0;
627 // Count local symbols--implemented by child class.
629 do_count_local_symbols(Stringpool_template
<char>*,
630 Stringpool_template
<char>*) = 0;
632 // Finalize the local symbols. Set the output symbol table indexes
633 // for the local variables, and set the offset where local symbol
634 // information will be stored.
636 do_finalize_local_symbols(unsigned int, off_t
) = 0;
638 // Set the output dynamic symbol table indexes for the local variables.
640 do_set_local_dynsym_indexes(unsigned int) = 0;
642 // Set the offset where local dynamic symbol information will be stored.
644 do_set_local_dynsym_offset(off_t
) = 0;
646 // Relocate the input sections and write out the local
647 // symbols--implemented by child class.
649 do_relocate(const General_options
& options
, const Symbol_table
* symtab
,
650 const Layout
*, Output_file
* of
) = 0;
652 // Return the vector mapping input sections to output sections.
653 std::vector
<Map_to_output
>&
655 { return this->map_to_output_
; }
657 const std::vector
<Map_to_output
>&
658 map_to_output() const
659 { return this->map_to_output_
; }
661 // Set the size of the relocatable relocs array.
663 size_relocatable_relocs()
665 this->map_to_relocatable_relocs_
=
666 new std::vector
<Relocatable_relocs
*>(this->shnum());
669 // Record that we must wait for the output sections to be written
670 // before applying relocations.
672 set_relocs_must_follow_section_writes()
673 { this->relocs_must_follow_section_writes_
= true; }
676 // Mapping from input sections to output section.
677 std::vector
<Map_to_output
> map_to_output_
;
678 // Mapping from input section index to the information recorded for
679 // the relocations. This is only used for a relocatable link.
680 std::vector
<Relocatable_relocs
*>* map_to_relocatable_relocs_
;
681 // Mappings for merge sections. This is managed by the code in the
683 Object_merge_map
* object_merge_map_
;
684 // Whether we need to wait for output sections to be written before
685 // we can apply relocations.
686 bool relocs_must_follow_section_writes_
;
689 // Implement Object::output_section inline for efficiency.
690 inline Output_section
*
691 Relobj::output_section(unsigned int shndx
, section_offset_type
* poff
) const
693 gold_assert(shndx
< this->map_to_output_
.size());
694 const Map_to_output
& mo(this->map_to_output_
[shndx
]);
696 return mo
.output_section
;
699 // This class is used to handle relocations against a section symbol
700 // in an SHF_MERGE section. For such a symbol, we need to know the
701 // addend of the relocation before we can determine the final value.
702 // The addend gives us the location in the input section, and we can
703 // determine how it is mapped to the output section. For a
704 // non-section symbol, we apply the addend to the final value of the
705 // symbol; that is done in finalize_local_symbols, and does not use
709 class Merged_symbol_value
712 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Value
;
714 // We use a hash table to map offsets in the input section to output
716 typedef Unordered_map
<section_offset_type
, Value
> Output_addresses
;
718 Merged_symbol_value(Value input_value
, Value output_start_address
)
719 : input_value_(input_value
), output_start_address_(output_start_address
),
723 // Initialize the hash table.
725 initialize_input_to_output_map(const Relobj
*, unsigned int input_shndx
);
727 // Release the hash table to save space.
729 free_input_to_output_map()
730 { this->output_addresses_
.clear(); }
732 // Get the output value corresponding to an addend. The object and
733 // input section index are passed in because the caller will have
734 // them; otherwise we could store them here.
736 value(const Relobj
* object
, unsigned int input_shndx
, Value addend
) const
738 Value input_offset
= this->input_value_
+ addend
;
739 typename
Output_addresses::const_iterator p
=
740 this->output_addresses_
.find(input_offset
);
741 if (p
!= this->output_addresses_
.end())
744 return this->value_from_output_section(object
, input_shndx
, input_offset
);
748 // Get the output value for an input offset if we couldn't find it
749 // in the hash table.
751 value_from_output_section(const Relobj
*, unsigned int input_shndx
,
752 Value input_offset
) const;
754 // The value of the section symbol in the input file. This is
755 // normally zero, but could in principle be something else.
757 // The start address of this merged section in the output file.
758 Value output_start_address_
;
759 // A hash table which maps offsets in the input section to output
760 // addresses. This only maps specific offsets, not all offsets.
761 Output_addresses output_addresses_
;
764 // This POD class is holds the value of a symbol. This is used for
765 // local symbols, and for all symbols during relocation processing.
766 // For special sections, such as SHF_MERGE sections, this calls a
767 // function to get the final symbol value.
773 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Value
;
776 : output_symtab_index_(0), output_dynsym_index_(-1U), input_shndx_(0),
777 is_section_symbol_(false), is_tls_symbol_(false),
778 has_output_value_(true)
779 { this->u_
.value
= 0; }
781 // Get the value of this symbol. OBJECT is the object in which this
782 // symbol is defined, and ADDEND is an addend to add to the value.
783 template<bool big_endian
>
785 value(const Sized_relobj
<size
, big_endian
>* object
, Value addend
) const
787 if (this->has_output_value_
)
788 return this->u_
.value
+ addend
;
790 return this->u_
.merged_symbol_value
->value(object
, this->input_shndx_
,
794 // Set the value of this symbol in the output symbol table.
796 set_output_value(Value value
)
797 { this->u_
.value
= value
; }
799 // For a section symbol in a merged section, we need more
802 set_merged_symbol_value(Merged_symbol_value
<size
>* msv
)
804 gold_assert(this->is_section_symbol_
);
805 this->has_output_value_
= false;
806 this->u_
.merged_symbol_value
= msv
;
809 // Initialize the input to output map for a section symbol in a
810 // merged section. We also initialize the value of a non-section
811 // symbol in a merged section.
813 initialize_input_to_output_map(const Relobj
* object
)
815 if (!this->has_output_value_
)
817 gold_assert(this->is_section_symbol_
);
818 Merged_symbol_value
<size
>* msv
= this->u_
.merged_symbol_value
;
819 msv
->initialize_input_to_output_map(object
, this->input_shndx_
);
823 // Free the input to output map for a section symbol in a merged
826 free_input_to_output_map()
828 if (!this->has_output_value_
)
829 this->u_
.merged_symbol_value
->free_input_to_output_map();
832 // Set the value of the symbol from the input file. This is only
833 // called by count_local_symbols, to communicate the value to
834 // finalize_local_symbols.
836 set_input_value(Value value
)
837 { this->u_
.value
= value
; }
839 // Return the input value. This is only called by
840 // finalize_local_symbols.
843 { return this->u_
.value
; }
845 // Return whether this symbol should go into the output symbol
848 needs_output_symtab_entry() const
849 { return this->output_symtab_index_
!= -1U; }
851 // Return the index in the output symbol table.
853 output_symtab_index() const
855 gold_assert(this->output_symtab_index_
!= 0);
856 return this->output_symtab_index_
;
859 // Set the index in the output symbol table.
861 set_output_symtab_index(unsigned int i
)
863 gold_assert(this->output_symtab_index_
== 0);
864 this->output_symtab_index_
= i
;
867 // Record that this symbol should not go into the output symbol
870 set_no_output_symtab_entry()
872 gold_assert(this->output_symtab_index_
== 0);
873 this->output_symtab_index_
= -1U;
876 // Set the index in the output dynamic symbol table.
878 set_needs_output_dynsym_entry()
880 gold_assert(!this->is_section_symbol());
881 this->output_dynsym_index_
= 0;
884 // Return whether this symbol should go into the output symbol
887 needs_output_dynsym_entry() const
889 return this->output_dynsym_index_
!= -1U;
892 // Record that this symbol should go into the dynamic symbol table.
894 set_output_dynsym_index(unsigned int i
)
896 gold_assert(this->output_dynsym_index_
== 0);
897 this->output_dynsym_index_
= i
;
900 // Return the index in the output dynamic symbol table.
902 output_dynsym_index() const
904 gold_assert(this->output_dynsym_index_
!= 0
905 && this->output_dynsym_index_
!= -1U);
906 return this->output_dynsym_index_
;
909 // Set the index of the input section in the input file.
911 set_input_shndx(unsigned int i
)
913 this->input_shndx_
= i
;
914 // input_shndx_ field is a bitfield, so make sure that the value
916 gold_assert(this->input_shndx_
== i
);
919 // Return the index of the input section in the input file.
922 { return this->input_shndx_
; }
924 // Whether this is a section symbol.
926 is_section_symbol() const
927 { return this->is_section_symbol_
; }
929 // Record that this is a section symbol.
931 set_is_section_symbol()
933 gold_assert(!this->needs_output_dynsym_entry());
934 this->is_section_symbol_
= true;
937 // Record that this is a TLS symbol.
940 { this->is_tls_symbol_
= true; }
942 // Return TRUE if this is a TLS symbol.
944 is_tls_symbol() const
945 { return this->is_tls_symbol_
; }
948 // The index of this local symbol in the output symbol table. This
949 // will be -1 if the symbol should not go into the symbol table.
950 unsigned int output_symtab_index_
;
951 // The index of this local symbol in the dynamic symbol table. This
952 // will be -1 if the symbol should not go into the symbol table.
953 unsigned int output_dynsym_index_
;
954 // The section index in the input file in which this symbol is
956 unsigned int input_shndx_
: 29;
957 // Whether this is a STT_SECTION symbol.
958 bool is_section_symbol_
: 1;
959 // Whether this is a STT_TLS symbol.
960 bool is_tls_symbol_
: 1;
961 // Whether this symbol has a value for the output file. This is
962 // normally set to true during Layout::finalize, by
963 // finalize_local_symbols. It will be false for a section symbol in
964 // a merge section, as for such symbols we can not determine the
965 // value to use in a relocation until we see the addend.
966 bool has_output_value_
: 1;
969 // This is used if has_output_value_ is true. Between
970 // count_local_symbols and finalize_local_symbols, this is the
971 // value in the input file. After finalize_local_symbols, it is
972 // the value in the output file.
974 // This is used if has_output_value_ is false. It points to the
975 // information we need to get the value for a merge section.
976 Merged_symbol_value
<size
>* merged_symbol_value
;
980 // A GOT offset list. A symbol may have more than one GOT offset
981 // (e.g., when mixing modules compiled with two different TLS models),
982 // but will usually have at most one. GOT_TYPE identifies the type of
983 // GOT entry; its values are specific to each target.
985 class Got_offset_list
989 : got_type_(-1U), got_offset_(0), got_next_(NULL
)
992 Got_offset_list(unsigned int got_type
, unsigned int got_offset
)
993 : got_type_(got_type
), got_offset_(got_offset
), got_next_(NULL
)
998 if (this->got_next_
!= NULL
)
1000 delete this->got_next_
;
1001 this->got_next_
= NULL
;
1005 // Initialize the fields to their default values.
1009 this->got_type_
= -1U;
1010 this->got_offset_
= 0;
1011 this->got_next_
= NULL
;
1014 // Set the offset for the GOT entry of type GOT_TYPE.
1016 set_offset(unsigned int got_type
, unsigned int got_offset
)
1018 if (this->got_type_
== -1U)
1020 this->got_type_
= got_type
;
1021 this->got_offset_
= got_offset
;
1025 for (Got_offset_list
* g
= this; g
!= NULL
; g
= g
->got_next_
)
1027 if (g
->got_type_
== got_type
)
1029 g
->got_offset_
= got_offset
;
1033 Got_offset_list
* g
= new Got_offset_list(got_type
, got_offset
);
1034 g
->got_next_
= this->got_next_
;
1035 this->got_next_
= g
;
1039 // Return the offset for a GOT entry of type GOT_TYPE.
1041 get_offset(unsigned int got_type
) const
1043 for (const Got_offset_list
* g
= this; g
!= NULL
; g
= g
->got_next_
)
1045 if (g
->got_type_
== got_type
)
1046 return g
->got_offset_
;
1052 unsigned int got_type_
;
1053 unsigned int got_offset_
;
1054 Got_offset_list
* got_next_
;
1057 // A regular object file. This is size and endian specific.
1059 template<int size
, bool big_endian
>
1060 class Sized_relobj
: public Relobj
1063 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Address
;
1064 typedef std::vector
<Symbol
*> Symbols
;
1065 typedef std::vector
<Symbol_value
<size
> > Local_values
;
1067 Sized_relobj(const std::string
& name
, Input_file
* input_file
, off_t offset
,
1068 const typename
elfcpp::Ehdr
<size
, big_endian
>&);
1072 // Set up the object file based on the ELF header.
1074 setup(const typename
elfcpp::Ehdr
<size
, big_endian
>&);
1076 // If SYM is the index of a global symbol in the object file's
1077 // symbol table, return the Symbol object. Otherwise, return NULL.
1079 global_symbol(unsigned int sym
) const
1081 if (sym
>= this->local_symbol_count_
)
1083 gold_assert(sym
- this->local_symbol_count_
< this->symbols_
.size());
1084 return this->symbols_
[sym
- this->local_symbol_count_
];
1089 // Return the section index of symbol SYM. Set *VALUE to its value
1090 // in the object file. Note that for a symbol which is not defined
1091 // in this object file, this will set *VALUE to 0 and return
1092 // SHN_UNDEF; it will not return the final value of the symbol in
1095 symbol_section_and_value(unsigned int sym
, Address
* value
);
1097 // Return a pointer to the Symbol_value structure which holds the
1098 // value of a local symbol.
1099 const Symbol_value
<size
>*
1100 local_symbol(unsigned int sym
) const
1102 gold_assert(sym
< this->local_values_
.size());
1103 return &this->local_values_
[sym
];
1106 // Return the index of local symbol SYM in the ordinary symbol
1107 // table. A value of -1U means that the symbol is not being output.
1109 symtab_index(unsigned int sym
) const
1111 gold_assert(sym
< this->local_values_
.size());
1112 return this->local_values_
[sym
].output_symtab_index();
1115 // Return the index of local symbol SYM in the dynamic symbol
1116 // table. A value of -1U means that the symbol is not being output.
1118 dynsym_index(unsigned int sym
) const
1120 gold_assert(sym
< this->local_values_
.size());
1121 return this->local_values_
[sym
].output_dynsym_index();
1124 // Return the input section index of local symbol SYM.
1126 local_symbol_input_shndx(unsigned int sym
) const
1128 gold_assert(sym
< this->local_values_
.size());
1129 return this->local_values_
[sym
].input_shndx();
1132 // Return the appropriate Sized_target structure.
1133 Sized_target
<size
, big_endian
>*
1135 { return this->Object::sized_target
<size
, big_endian
>(); }
1137 // Record that local symbol SYM needs a dynamic symbol entry.
1139 set_needs_output_dynsym_entry(unsigned int sym
)
1141 gold_assert(sym
< this->local_values_
.size());
1142 this->local_values_
[sym
].set_needs_output_dynsym_entry();
1145 // Return whether the local symbol SYMNDX has a GOT offset.
1146 // For TLS symbols, the GOT entry will hold its tp-relative offset.
1148 local_has_got_offset(unsigned int symndx
, unsigned int got_type
) const
1150 Local_got_offsets::const_iterator p
=
1151 this->local_got_offsets_
.find(symndx
);
1152 return (p
!= this->local_got_offsets_
.end()
1153 && p
->second
->get_offset(got_type
) != -1U);
1156 // Return the GOT offset of the local symbol SYMNDX.
1158 local_got_offset(unsigned int symndx
, unsigned int got_type
) const
1160 Local_got_offsets::const_iterator p
=
1161 this->local_got_offsets_
.find(symndx
);
1162 gold_assert(p
!= this->local_got_offsets_
.end());
1163 unsigned int off
= p
->second
->get_offset(got_type
);
1164 gold_assert(off
!= -1U);
1168 // Set the GOT offset of the local symbol SYMNDX to GOT_OFFSET.
1170 set_local_got_offset(unsigned int symndx
, unsigned int got_type
,
1171 unsigned int got_offset
)
1173 Local_got_offsets::const_iterator p
=
1174 this->local_got_offsets_
.find(symndx
);
1175 if (p
!= this->local_got_offsets_
.end())
1176 p
->second
->set_offset(got_type
, got_offset
);
1179 Got_offset_list
* g
= new Got_offset_list(got_type
, got_offset
);
1180 std::pair
<Local_got_offsets::iterator
, bool> ins
=
1181 this->local_got_offsets_
.insert(std::make_pair(symndx
, g
));
1182 gold_assert(ins
.second
);
1186 // Return the name of the symbol that spans the given offset in the
1187 // specified section in this object. This is used only for error
1188 // messages and is not particularly efficient.
1190 get_symbol_location_info(unsigned int shndx
, off_t offset
,
1191 Symbol_location_info
* info
);
1194 // Read the symbols.
1196 do_read_symbols(Read_symbols_data
*);
1198 // Return the number of local symbols.
1200 do_local_symbol_count() const
1201 { return this->local_symbol_count_
; }
1203 // Lay out the input sections.
1205 do_layout(Symbol_table
*, Layout
*, Read_symbols_data
*);
1207 // Add the symbols to the symbol table.
1209 do_add_symbols(Symbol_table
*, Read_symbols_data
*);
1213 do_read_relocs(Read_relocs_data
*);
1215 // Scan the relocs and adjust the symbol table.
1217 do_scan_relocs(const General_options
&, Symbol_table
*, Layout
*,
1220 // Count the local symbols.
1222 do_count_local_symbols(Stringpool_template
<char>*,
1223 Stringpool_template
<char>*);
1225 // Finalize the local symbols.
1227 do_finalize_local_symbols(unsigned int, off_t
);
1229 // Set the offset where local dynamic symbol information will be stored.
1231 do_set_local_dynsym_indexes(unsigned int);
1233 // Set the offset where local dynamic symbol information will be stored.
1235 do_set_local_dynsym_offset(off_t
);
1237 // Relocate the input sections and write out the local symbols.
1239 do_relocate(const General_options
& options
, const Symbol_table
* symtab
,
1240 const Layout
*, Output_file
* of
);
1242 // Get the size of a section.
1244 do_section_size(unsigned int shndx
)
1245 { return this->elf_file_
.section_size(shndx
); }
1247 // Get the name of a section.
1249 do_section_name(unsigned int shndx
)
1250 { return this->elf_file_
.section_name(shndx
); }
1252 // Return the location of the contents of a section.
1254 do_section_contents(unsigned int shndx
)
1255 { return this->elf_file_
.section_contents(shndx
); }
1257 // Return section flags.
1259 do_section_flags(unsigned int shndx
)
1260 { return this->elf_file_
.section_flags(shndx
); }
1262 // Return section address.
1264 do_section_address(unsigned int shndx
)
1265 { return this->elf_file_
.section_addr(shndx
); }
1267 // Return section type.
1269 do_section_type(unsigned int shndx
)
1270 { return this->elf_file_
.section_type(shndx
); }
1272 // Return the section link field.
1274 do_section_link(unsigned int shndx
)
1275 { return this->elf_file_
.section_link(shndx
); }
1277 // Return the section info field.
1279 do_section_info(unsigned int shndx
)
1280 { return this->elf_file_
.section_info(shndx
); }
1282 // Return the section alignment.
1284 do_section_addralign(unsigned int shndx
)
1285 { return this->elf_file_
.section_addralign(shndx
); }
1289 typedef Sized_relobj
<size
, big_endian
> This
;
1290 static const int ehdr_size
= elfcpp::Elf_sizes
<size
>::ehdr_size
;
1291 static const int shdr_size
= elfcpp::Elf_sizes
<size
>::shdr_size
;
1292 static const int sym_size
= elfcpp::Elf_sizes
<size
>::sym_size
;
1293 typedef elfcpp::Shdr
<size
, big_endian
> Shdr
;
1295 // Find the SHT_SYMTAB section, given the section headers.
1297 find_symtab(const unsigned char* pshdrs
);
1299 // Return whether SHDR has the right flags for a GNU style exception
1302 check_eh_frame_flags(const elfcpp::Shdr
<size
, big_endian
>* shdr
) const;
1304 // Return whether there is a section named .eh_frame which might be
1305 // a GNU style exception frame section.
1307 find_eh_frame(const unsigned char* pshdrs
, const char* names
,
1308 section_size_type names_size
) const;
1310 // Whether to include a section group in the link.
1312 include_section_group(Symbol_table
*, Layout
*, unsigned int, const char*,
1313 const elfcpp::Shdr
<size
, big_endian
>&,
1314 std::vector
<bool>*);
1316 // Whether to include a linkonce section in the link.
1318 include_linkonce_section(Layout
*, const char*,
1319 const elfcpp::Shdr
<size
, big_endian
>&);
1321 // Views and sizes when relocating.
1324 unsigned char* view
;
1325 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
;
1327 section_size_type view_size
;
1328 bool is_input_output_view
;
1329 bool is_postprocessing_view
;
1332 typedef std::vector
<View_size
> Views
;
1334 // Write section data to the output file. Record the views and
1335 // sizes in VIEWS for use when relocating.
1337 write_sections(const unsigned char* pshdrs
, Output_file
*, Views
*);
1339 // Relocate the sections in the output file.
1341 relocate_sections(const General_options
& options
, const Symbol_table
*,
1342 const Layout
*, const unsigned char* pshdrs
, Views
*);
1344 // Scan the input relocations for --emit-relocs.
1346 emit_relocs_scan(const General_options
&, Symbol_table
*, Layout
*,
1347 const unsigned char* plocal_syms
,
1348 const Read_relocs_data::Relocs_list::iterator
&);
1350 // Scan the input relocations for --emit-relocs, templatized on the
1351 // type of the relocation section.
1352 template<int sh_type
>
1354 emit_relocs_scan_reltype(const General_options
&, Symbol_table
*, Layout
*,
1355 const unsigned char* plocal_syms
,
1356 const Read_relocs_data::Relocs_list::iterator
&,
1357 Relocatable_relocs
*);
1359 // Emit the relocs for --emit-relocs.
1361 emit_relocs(const Relocate_info
<size
, big_endian
>*, unsigned int,
1362 unsigned int sh_type
, const unsigned char* prelocs
,
1363 size_t reloc_count
, Output_section
*, off_t output_offset
,
1364 unsigned char* view
, Address address
,
1365 section_size_type view_size
,
1366 unsigned char* reloc_view
, section_size_type reloc_view_size
);
1368 // Emit the relocs for --emit-relocs, templatized on the type of the
1369 // relocation section.
1370 template<int sh_type
>
1372 emit_relocs_reltype(const Relocate_info
<size
, big_endian
>*, unsigned int,
1373 const unsigned char* prelocs
, size_t reloc_count
,
1374 Output_section
*, off_t output_offset
,
1375 unsigned char* view
, Address address
,
1376 section_size_type view_size
,
1377 unsigned char* reloc_view
,
1378 section_size_type reloc_view_size
);
1380 // Initialize input to output maps for section symbols in merged
1383 initialize_input_to_output_maps();
1385 // Free the input to output maps for section symbols in merged
1388 free_input_to_output_maps();
1390 // Write out the local symbols.
1392 write_local_symbols(Output_file
*,
1393 const Stringpool_template
<char>*,
1394 const Stringpool_template
<char>*);
1396 // Clear the local symbol information.
1398 clear_local_symbols()
1400 this->local_values_
.clear();
1401 this->local_got_offsets_
.clear();
1404 // The GOT offsets of local symbols. This map also stores GOT offsets
1405 // for tp-relative offsets for TLS symbols.
1406 typedef Unordered_map
<unsigned int, Got_offset_list
*> Local_got_offsets
;
1408 // The TLS GOT offsets of local symbols. The map stores the offsets
1409 // for either a single GOT entry that holds the module index of a TLS
1410 // symbol, or a pair of GOT entries containing the module index and
1411 // dtv-relative offset.
1412 struct Tls_got_entry
1414 Tls_got_entry(int got_offset
, bool have_pair
)
1415 : got_offset_(got_offset
),
1416 have_pair_(have_pair
)
1421 typedef Unordered_map
<unsigned int, Tls_got_entry
> Local_tls_got_offsets
;
1423 // General access to the ELF file.
1424 elfcpp::Elf_file
<size
, big_endian
, Object
> elf_file_
;
1425 // Index of SHT_SYMTAB section.
1426 unsigned int symtab_shndx_
;
1427 // The number of local symbols.
1428 unsigned int local_symbol_count_
;
1429 // The number of local symbols which go into the output file.
1430 unsigned int output_local_symbol_count_
;
1431 // The number of local symbols which go into the output file's dynamic
1433 unsigned int output_local_dynsym_count_
;
1434 // The entries in the symbol table for the external symbols.
1436 // File offset for local symbols.
1437 off_t local_symbol_offset_
;
1438 // File offset for local dynamic symbols.
1439 off_t local_dynsym_offset_
;
1440 // Values of local symbols.
1441 Local_values local_values_
;
1442 // GOT offsets for local non-TLS symbols, and tp-relative offsets
1443 // for TLS symbols, indexed by symbol number.
1444 Local_got_offsets local_got_offsets_
;
1445 // Whether this object has a GNU style .eh_frame section.
1449 // A class to manage the list of all objects.
1455 : relobj_list_(), dynobj_list_(), sonames_(), system_library_directory_()
1458 // The type of the list of input relocateable objects.
1459 typedef std::vector
<Relobj
*> Relobj_list
;
1460 typedef Relobj_list::const_iterator Relobj_iterator
;
1462 // The type of the list of input dynamic objects.
1463 typedef std::vector
<Dynobj
*> Dynobj_list
;
1464 typedef Dynobj_list::const_iterator Dynobj_iterator
;
1466 // Add an object to the list. Return true if all is well, or false
1467 // if this object should be ignored.
1469 add_object(Object
*);
1471 // For each dynamic object, check whether we've seen all of its
1472 // explicit dependencies.
1474 check_dynamic_dependencies() const;
1476 // Return whether an object was found in the system library
1479 found_in_system_library_directory(const Object
*) const;
1481 // Iterate over all regular objects.
1484 relobj_begin() const
1485 { return this->relobj_list_
.begin(); }
1489 { return this->relobj_list_
.end(); }
1491 // Iterate over all dynamic objects.
1494 dynobj_begin() const
1495 { return this->dynobj_list_
.begin(); }
1499 { return this->dynobj_list_
.end(); }
1501 // Return whether we have seen any dynamic objects.
1504 { return !this->dynobj_list_
.empty(); }
1506 // Return the number of input objects.
1508 number_of_input_objects() const
1509 { return this->relobj_list_
.size() + this->dynobj_list_
.size(); }
1512 Input_objects(const Input_objects
&);
1513 Input_objects
& operator=(const Input_objects
&);
1515 // The list of ordinary objects included in the link.
1516 Relobj_list relobj_list_
;
1517 // The list of dynamic objects included in the link.
1518 Dynobj_list dynobj_list_
;
1519 // SONAMEs that we have seen.
1520 Unordered_set
<std::string
> sonames_
;
1521 // The directory in which we find the libc.so.
1522 std::string system_library_directory_
;
1525 // Some of the information we pass to the relocation routines. We
1526 // group this together to avoid passing a dozen different arguments.
1528 template<int size
, bool big_endian
>
1529 struct Relocate_info
1531 // Command line options.
1532 const General_options
* options
;
1534 const Symbol_table
* symtab
;
1536 const Layout
* layout
;
1537 // Object being relocated.
1538 Sized_relobj
<size
, big_endian
>* object
;
1539 // Section index of relocation section.
1540 unsigned int reloc_shndx
;
1541 // Section index of section being relocated.
1542 unsigned int data_shndx
;
1544 // Return a string showing the location of a relocation. This is
1545 // only used for error messages.
1547 location(size_t relnum
, off_t reloffset
) const;
1550 // Return an Object appropriate for the input file. P is BYTES long,
1551 // and holds the ELF header.
1554 make_elf_object(const std::string
& name
, Input_file
*,
1555 off_t offset
, const unsigned char* p
,
1556 section_offset_type bytes
);
1558 } // end namespace gold
1560 #endif // !defined(GOLD_OBJECT_H)