1 // object.h -- support for an object file for linking in gold -*- C++ -*-
3 // Copyright 2006, 2007, 2008, 2009, 2010 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"
38 class General_options
;
44 class Output_symtab_xindex
;
47 class Object_merge_map
;
48 class Relocatable_relocs
;
51 template<typename Stringpool_char
>
52 class Stringpool_template
;
54 // Data to pass from read_symbols() to add_symbols().
56 struct Read_symbols_data
59 : section_headers(NULL
), section_names(NULL
), symbols(NULL
),
60 symbol_names(NULL
), versym(NULL
), verdef(NULL
), verneed(NULL
)
66 File_view
* section_headers
;
68 File_view
* section_names
;
69 // Size of section name data in bytes.
70 section_size_type section_names_size
;
73 // Size of symbol data in bytes.
74 section_size_type symbols_size
;
75 // Offset of external symbols within symbol data. This structure
76 // sometimes contains only external symbols, in which case this will
77 // be zero. Sometimes it contains all symbols.
78 section_offset_type external_symbols_offset
;
80 File_view
* symbol_names
;
81 // Size of symbol name data in bytes.
82 section_size_type symbol_names_size
;
84 // Version information. This is only used on dynamic objects.
85 // Version symbol data (from SHT_GNU_versym section).
87 section_size_type versym_size
;
88 // Version definition data (from SHT_GNU_verdef section).
90 section_size_type verdef_size
;
91 unsigned int verdef_info
;
92 // Needed version data (from SHT_GNU_verneed section).
94 section_size_type verneed_size
;
95 unsigned int verneed_info
;
98 // Information used to print error messages.
100 struct Symbol_location_info
102 std::string source_file
;
103 std::string enclosing_symbol_name
;
107 // Data about a single relocation section. This is read in
108 // read_relocs and processed in scan_relocs.
110 struct Section_relocs
117 { delete this->contents
; }
119 // Index of reloc section.
120 unsigned int reloc_shndx
;
121 // Index of section that relocs apply to.
122 unsigned int data_shndx
;
123 // Contents of reloc section.
125 // Reloc section type.
126 unsigned int sh_type
;
127 // Number of reloc entries.
130 Output_section
* output_section
;
131 // Whether this section has special handling for offsets.
132 bool needs_special_offset_handling
;
133 // Whether the data section is allocated (has the SHF_ALLOC flag set).
134 bool is_data_section_allocated
;
137 // Relocations in an object file. This is read in read_relocs and
138 // processed in scan_relocs.
140 struct Read_relocs_data
143 : local_symbols(NULL
)
147 { delete this->local_symbols
; }
149 typedef std::vector
<Section_relocs
> Relocs_list
;
152 // The local symbols.
153 File_view
* local_symbols
;
156 // The Xindex class manages section indexes for objects with more than
162 Xindex(int large_shndx_offset
)
163 : large_shndx_offset_(large_shndx_offset
), symtab_xindex_()
166 // Initialize the symtab_xindex_ array, given the object and the
167 // section index of the symbol table to use.
168 template<int size
, bool big_endian
>
170 initialize_symtab_xindex(Object
*, unsigned int symtab_shndx
);
172 // Read in the symtab_xindex_ array, given its section index.
173 // PSHDRS may optionally point to the section headers.
174 template<int size
, bool big_endian
>
176 read_symtab_xindex(Object
*, unsigned int xindex_shndx
,
177 const unsigned char* pshdrs
);
179 // Symbol SYMNDX in OBJECT has a section of SHN_XINDEX; return the
180 // real section index.
182 sym_xindex_to_shndx(Object
* object
, unsigned int symndx
);
185 // The type of the array giving the real section index for symbols
186 // whose st_shndx field holds SHN_XINDEX.
187 typedef std::vector
<unsigned int> Symtab_xindex
;
189 // Adjust a section index if necessary. This should only be called
190 // for ordinary section indexes.
192 adjust_shndx(unsigned int shndx
)
194 if (shndx
>= elfcpp::SHN_LORESERVE
)
195 shndx
+= this->large_shndx_offset_
;
199 // Adjust to apply to large section indexes.
200 int large_shndx_offset_
;
201 // The data from the SHT_SYMTAB_SHNDX section.
202 Symtab_xindex symtab_xindex_
;
205 // Object is an abstract base class which represents either a 32-bit
206 // or a 64-bit input object. This can be a regular object file
207 // (ET_REL) or a shared object (ET_DYN).
212 typedef std::vector
<Symbol
*> Symbols
;
214 // NAME is the name of the object as we would report it to the user
215 // (e.g., libfoo.a(bar.o) if this is in an archive. INPUT_FILE is
216 // used to read the file. OFFSET is the offset within the input
217 // file--0 for a .o or .so file, something else for a .a file.
218 Object(const std::string
& name
, Input_file
* input_file
, bool is_dynamic
,
220 : name_(name
), input_file_(input_file
), offset_(offset
), shnum_(-1U),
221 is_dynamic_(is_dynamic
), is_needed_(false), uses_split_stack_(false),
222 has_no_split_stack_(false), no_export_(false), xindex_(NULL
)
223 { input_file
->file().add_object(); }
226 { this->input_file_
->file().remove_object(); }
228 // Return the name of the object as we would report it to the tuser.
231 { return this->name_
; }
233 // Get the offset into the file.
236 { return this->offset_
; }
238 // Return whether this is a dynamic object.
241 { return this->is_dynamic_
; }
243 // Return whether this object is needed--true if it is a dynamic
244 // object which defines some symbol referenced by a regular object.
245 // We keep the flag here rather than in Dynobj for convenience when
249 { return this->is_needed_
; }
251 // Record that this object is needed.
254 { this->is_needed_
= true; }
256 // Return whether this object was compiled with -fsplit-stack.
258 uses_split_stack() const
259 { return this->uses_split_stack_
; }
261 // Return whether this object contains any functions compiled with
262 // the no_split_stack attribute.
264 has_no_split_stack() const
265 { return this->has_no_split_stack_
; }
267 // Returns NULL for Objects that are not plugin objects. This method
268 // is overridden in the Pluginobj class.
271 { return this->do_pluginobj(); }
273 // Get the file. We pass on const-ness.
276 { return this->input_file_
; }
280 { return this->input_file_
; }
282 // Lock the underlying file.
285 { this->input_file()->file().lock(t
); }
287 // Unlock the underlying file.
289 unlock(const Task
* t
)
290 { this->input_file()->file().unlock(t
); }
292 // Return whether the underlying file is locked.
295 { return this->input_file()->file().is_locked(); }
297 // Return the token, so that the task can be queued.
300 { return this->input_file()->file().token(); }
302 // Release the underlying file.
305 { this->input_file_
->file().release(); }
307 // Return whether we should just read symbols from this file.
310 { return this->input_file()->just_symbols(); }
312 // Get the number of sections.
315 { return this->shnum_
; }
317 // Return a view of the contents of a section. Set *PLEN to the
318 // size. CACHE is a hint as in File_read::get_view.
320 section_contents(unsigned int shndx
, section_size_type
* plen
, bool cache
);
322 // Adjust a symbol's section index as needed. SYMNDX is the index
323 // of the symbol and SHNDX is the symbol's section from
324 // get_st_shndx. This returns the section index. It sets
325 // *IS_ORDINARY to indicate whether this is a normal section index,
326 // rather than a special code between SHN_LORESERVE and
329 adjust_sym_shndx(unsigned int symndx
, unsigned int shndx
, bool* is_ordinary
)
331 if (shndx
< elfcpp::SHN_LORESERVE
)
333 else if (shndx
== elfcpp::SHN_XINDEX
)
335 if (this->xindex_
== NULL
)
336 this->xindex_
= this->do_initialize_xindex();
337 shndx
= this->xindex_
->sym_xindex_to_shndx(this, symndx
);
341 *is_ordinary
= false;
345 // Return the size of a section given a section index.
347 section_size(unsigned int shndx
)
348 { return this->do_section_size(shndx
); }
350 // Return the name of a section given a section index.
352 section_name(unsigned int shndx
)
353 { return this->do_section_name(shndx
); }
355 // Return the section flags given a section index.
357 section_flags(unsigned int shndx
)
358 { return this->do_section_flags(shndx
); }
360 // Return the section entsize given a section index.
362 section_entsize(unsigned int shndx
)
363 { return this->do_section_entsize(shndx
); }
365 // Return the section address given a section index.
367 section_address(unsigned int shndx
)
368 { return this->do_section_address(shndx
); }
370 // Return the section type given a section index.
372 section_type(unsigned int shndx
)
373 { return this->do_section_type(shndx
); }
375 // Return the section link field given a section index.
377 section_link(unsigned int shndx
)
378 { return this->do_section_link(shndx
); }
380 // Return the section info field given a section index.
382 section_info(unsigned int shndx
)
383 { return this->do_section_info(shndx
); }
385 // Return the required section alignment given a section index.
387 section_addralign(unsigned int shndx
)
388 { return this->do_section_addralign(shndx
); }
390 // Return the output section given a section index.
392 output_section(unsigned int shndx
) const
393 { return this->do_output_section(shndx
); }
395 // Given a section index, return the offset in the Output_section.
396 // The return value will be -1U if the section is specially mapped,
397 // such as a merge section.
399 output_section_offset(unsigned int shndx
) const
400 { return this->do_output_section_offset(shndx
); }
402 // Read the symbol information.
404 read_symbols(Read_symbols_data
* sd
)
405 { return this->do_read_symbols(sd
); }
407 // Pass sections which should be included in the link to the Layout
408 // object, and record where the sections go in the output file.
410 layout(Symbol_table
* symtab
, Layout
* layout
, Read_symbols_data
* sd
)
411 { this->do_layout(symtab
, layout
, sd
); }
413 // Add symbol information to the global symbol table.
415 add_symbols(Symbol_table
* symtab
, Read_symbols_data
* sd
, Layout
*layout
)
416 { this->do_add_symbols(symtab
, sd
, layout
); }
418 // Add symbol information to the global symbol table.
419 Archive::Should_include
420 should_include_member(Symbol_table
* symtab
, Layout
* layout
,
421 Read_symbols_data
* sd
, std::string
* why
)
422 { return this->do_should_include_member(symtab
, layout
, sd
, why
); }
424 // Functions and types for the elfcpp::Elf_file interface. This
425 // permit us to use Object as the File template parameter for
428 // The View class is returned by view. It must support a single
429 // method, data(). This is trivial, because get_view does what we
434 View(const unsigned char* p
)
443 const unsigned char* p_
;
448 view(off_t file_offset
, section_size_type data_size
)
449 { return View(this->get_view(file_offset
, data_size
, true, true)); }
453 error(const char* format
, ...) const ATTRIBUTE_PRINTF_2
;
455 // A location in the file.
461 Location(off_t fo
, section_size_type ds
)
462 : file_offset(fo
), data_size(ds
)
466 // Get a View given a Location.
467 View
view(Location loc
)
468 { return View(this->get_view(loc
.file_offset
, loc
.data_size
, true, true)); }
470 // Get a view into the underlying file.
472 get_view(off_t start
, section_size_type size
, bool aligned
, bool cache
)
474 return this->input_file()->file().get_view(this->offset_
, start
, size
,
478 // Get a lasting view into the underlying file.
480 get_lasting_view(off_t start
, section_size_type size
, bool aligned
,
483 return this->input_file()->file().get_lasting_view(this->offset_
, start
,
484 size
, aligned
, cache
);
487 // Read data from the underlying file.
489 read(off_t start
, section_size_type size
, void* p
)
490 { this->input_file()->file().read(start
+ this->offset_
, size
, p
); }
492 // Read multiple data from the underlying file.
494 read_multiple(const File_read::Read_multiple
& rm
)
495 { this->input_file()->file().read_multiple(this->offset_
, rm
); }
497 // Stop caching views in the underlying file.
499 clear_view_cache_marks()
500 { this->input_file()->file().clear_view_cache_marks(); }
502 // Get the number of global symbols defined by this object, and the
503 // number of the symbols whose final definition came from this
506 get_global_symbol_counts(const Symbol_table
* symtab
, size_t* defined
,
508 { this->do_get_global_symbol_counts(symtab
, defined
, used
); }
510 // Get the symbols defined in this object.
512 get_global_symbols() const
513 { return this->do_get_global_symbols(); }
515 // Return whether this object was found in a system directory.
517 is_in_system_directory() const
518 { return this->input_file()->is_in_system_directory(); }
520 // Return whether we found this object by searching a directory.
523 { return this->input_file()->will_search_for(); }
527 { return this->no_export_
; }
530 set_no_export(bool value
)
531 { this->no_export_
= value
; }
533 // Return TRUE if the section is a compressed debug section, and set
534 // *UNCOMPRESSED_SIZE to the size of the uncompressed data.
536 section_is_compressed(unsigned int shndx
,
537 section_size_type
* uncompressed_size
) const
538 { return this->do_section_is_compressed(shndx
, uncompressed_size
); }
540 // Return the index of the first incremental relocation for symbol SYMNDX.
542 get_incremental_reloc_base(unsigned int symndx
) const
543 { return this->do_get_incremental_reloc_base(symndx
); }
545 // Return the number of incremental relocations for symbol SYMNDX.
547 get_incremental_reloc_count(unsigned int symndx
) const
548 { return this->do_get_incremental_reloc_count(symndx
); }
551 // Returns NULL for Objects that are not plugin objects. This method
552 // is overridden in the Pluginobj class.
557 // Read the symbols--implemented by child class.
559 do_read_symbols(Read_symbols_data
*) = 0;
561 // Lay out sections--implemented by child class.
563 do_layout(Symbol_table
*, Layout
*, Read_symbols_data
*) = 0;
565 // Add symbol information to the global symbol table--implemented by
568 do_add_symbols(Symbol_table
*, Read_symbols_data
*, Layout
*) = 0;
570 virtual Archive::Should_include
571 do_should_include_member(Symbol_table
* symtab
, Layout
*, Read_symbols_data
*,
572 std::string
* why
) = 0;
574 // Return the location of the contents of a section. Implemented by
577 do_section_contents(unsigned int shndx
) = 0;
579 // Get the size of a section--implemented by child class.
581 do_section_size(unsigned int shndx
) = 0;
583 // Get the name of a section--implemented by child class.
585 do_section_name(unsigned int shndx
) = 0;
587 // Get section flags--implemented by child class.
589 do_section_flags(unsigned int shndx
) = 0;
591 // Get section entsize--implemented by child class.
593 do_section_entsize(unsigned int shndx
) = 0;
595 // Get section address--implemented by child class.
597 do_section_address(unsigned int shndx
) = 0;
599 // Get section type--implemented by child class.
601 do_section_type(unsigned int shndx
) = 0;
603 // Get section link field--implemented by child class.
605 do_section_link(unsigned int shndx
) = 0;
607 // Get section info field--implemented by child class.
609 do_section_info(unsigned int shndx
) = 0;
611 // Get section alignment--implemented by child class.
613 do_section_addralign(unsigned int shndx
) = 0;
615 // Return the output section given a section index--implemented
617 virtual Output_section
*
618 do_output_section(unsigned int) const
619 { gold_unreachable(); }
621 // Get the offset of a section--implemented by child class.
623 do_output_section_offset(unsigned int) const
624 { gold_unreachable(); }
626 // Return the Xindex structure to use.
628 do_initialize_xindex() = 0;
630 // Implement get_global_symbol_counts--implemented by child class.
632 do_get_global_symbol_counts(const Symbol_table
*, size_t*, size_t*) const = 0;
634 virtual const Symbols
*
635 do_get_global_symbols() const = 0;
637 // Set the number of sections.
640 { this->shnum_
= shnum
; }
642 // Functions used by both Sized_relobj and Sized_dynobj.
644 // Read the section data into a Read_symbols_data object.
645 template<int size
, bool big_endian
>
647 read_section_data(elfcpp::Elf_file
<size
, big_endian
, Object
>*,
650 // Let the child class initialize the xindex object directly.
652 set_xindex(Xindex
* xindex
)
654 gold_assert(this->xindex_
== NULL
);
655 this->xindex_
= xindex
;
658 // If NAME is the name of a special .gnu.warning section, arrange
659 // for the warning to be issued. SHNDX is the section index.
660 // Return whether it is a warning section.
662 handle_gnu_warning_section(const char* name
, unsigned int shndx
,
665 // If NAME is the name of the special section which indicates that
666 // this object was compiled with -fstack-split, mark it accordingly,
667 // and return true. Otherwise return false.
669 handle_split_stack_section(const char* name
);
671 // Return TRUE if the section is a compressed debug section, and set
672 // *UNCOMPRESSED_SIZE to the size of the uncompressed data.
674 do_section_is_compressed(unsigned int, section_size_type
*) const
677 // Return the index of the first incremental relocation for symbol SYMNDX--
678 // implemented by child class.
680 do_get_incremental_reloc_base(unsigned int) const
681 { gold_unreachable(); }
683 // Return the number of incremental relocations for symbol SYMNDX--
684 // implemented by child class.
686 do_get_incremental_reloc_count(unsigned int) const
687 { gold_unreachable(); }
690 // This class may not be copied.
691 Object(const Object
&);
692 Object
& operator=(const Object
&);
694 // Name of object as printed to user.
696 // For reading the file.
697 Input_file
* input_file_
;
698 // Offset within the file--0 for an object file, non-0 for an
701 // Number of input sections.
703 // Whether this is a dynamic object.
704 bool is_dynamic_
: 1;
705 // Whether this object is needed. This is only set for dynamic
706 // objects, and means that the object defined a symbol which was
707 // used by a reference from a regular object.
709 // Whether this object was compiled with -fsplit-stack.
710 bool uses_split_stack_
: 1;
711 // Whether this object contains any functions compiled with the
712 // no_split_stack attribute.
713 bool has_no_split_stack_
: 1;
714 // True if exclude this object from automatic symbol export.
715 // This is used only for archive objects.
717 // Many sections for objects with more than SHN_LORESERVE sections.
721 // A regular object (ET_REL). This is an abstract base class itself.
722 // The implementation is the template class Sized_relobj.
724 class Relobj
: public Object
727 Relobj(const std::string
& name
, Input_file
* input_file
, off_t offset
= 0)
728 : Object(name
, input_file
, false, offset
),
730 map_to_relocatable_relocs_(NULL
),
731 object_merge_map_(NULL
),
732 relocs_must_follow_section_writes_(false),
738 // During garbage collection, the Read_symbols_data pass for
739 // each object is stored as layout needs to be done after
743 { return this->sd_
; }
745 // Decides which section names have to be included in the worklist
748 is_section_name_included(const char *name
);
751 copy_symbols_data(Symbols_data
* gc_sd
, Read_symbols_data
* sd
,
752 unsigned int section_header_size
);
755 set_symbols_data(Symbols_data
* sd
)
758 // During garbage collection, the Read_relocs pass for all objects
759 // is done before scanning the relocs. In that case, this->rd_ is
760 // used to store the information from Read_relocs for each object.
761 // This data is also used to compute the list of relevant sections.
764 { return this->rd_
; }
767 set_relocs_data(Read_relocs_data
* rd
)
771 is_output_section_offset_invalid(unsigned int shndx
) const = 0;
775 read_relocs(Read_relocs_data
* rd
)
776 { return this->do_read_relocs(rd
); }
778 // Process the relocs, during garbage collection only.
780 gc_process_relocs(Symbol_table
* symtab
, Layout
* layout
, Read_relocs_data
* rd
)
781 { return this->do_gc_process_relocs(symtab
, layout
, rd
); }
783 // Scan the relocs and adjust the symbol table.
785 scan_relocs(Symbol_table
* symtab
, Layout
* layout
, Read_relocs_data
* rd
)
786 { return this->do_scan_relocs(symtab
, layout
, rd
); }
788 // The number of local symbols in the input symbol table.
790 local_symbol_count() const
791 { return this->do_local_symbol_count(); }
793 // Initial local symbol processing: count the number of local symbols
794 // in the output symbol table and dynamic symbol table; add local symbol
795 // names to *POOL and *DYNPOOL.
797 count_local_symbols(Stringpool_template
<char>* pool
,
798 Stringpool_template
<char>* dynpool
)
799 { return this->do_count_local_symbols(pool
, dynpool
); }
801 // Set the values of the local symbols, set the output symbol table
802 // indexes for the local variables, and set the offset where local
803 // symbol information will be stored. Returns the new local symbol index.
805 finalize_local_symbols(unsigned int index
, off_t off
, Symbol_table
* symtab
)
806 { return this->do_finalize_local_symbols(index
, off
, symtab
); }
808 // Set the output dynamic symbol table indexes for the local variables.
810 set_local_dynsym_indexes(unsigned int index
)
811 { return this->do_set_local_dynsym_indexes(index
); }
813 // Set the offset where local dynamic symbol information will be stored.
815 set_local_dynsym_offset(off_t off
)
816 { return this->do_set_local_dynsym_offset(off
); }
818 // Relocate the input sections and write out the local symbols.
820 relocate(const Symbol_table
* symtab
, const Layout
* layout
, Output_file
* of
)
821 { return this->do_relocate(symtab
, layout
, of
); }
823 // Return whether an input section is being included in the link.
825 is_section_included(unsigned int shndx
) const
827 gold_assert(shndx
< this->output_sections_
.size());
828 return this->output_sections_
[shndx
] != NULL
;
831 // The the output section of the input section with index SHNDX.
832 // This is only used currently to remove a section from the link in
835 set_output_section(unsigned int shndx
, Output_section
* os
)
837 gold_assert(shndx
< this->output_sections_
.size());
838 this->output_sections_
[shndx
] = os
;
841 // Set the offset of an input section within its output section.
843 set_section_offset(unsigned int shndx
, uint64_t off
)
844 { this->do_set_section_offset(shndx
, off
); }
846 // Return true if we need to wait for output sections to be written
847 // before we can apply relocations. This is true if the object has
848 // any relocations for sections which require special handling, such
849 // as the exception frame section.
851 relocs_must_follow_section_writes() const
852 { return this->relocs_must_follow_section_writes_
; }
854 // Return the object merge map.
857 { return this->object_merge_map_
; }
859 // Set the object merge map.
861 set_merge_map(Object_merge_map
* object_merge_map
)
863 gold_assert(this->object_merge_map_
== NULL
);
864 this->object_merge_map_
= object_merge_map
;
867 // Record the relocatable reloc info for an input reloc section.
869 set_relocatable_relocs(unsigned int reloc_shndx
, Relocatable_relocs
* rr
)
871 gold_assert(reloc_shndx
< this->shnum());
872 (*this->map_to_relocatable_relocs_
)[reloc_shndx
] = rr
;
875 // Get the relocatable reloc info for an input reloc section.
877 relocatable_relocs(unsigned int reloc_shndx
)
879 gold_assert(reloc_shndx
< this->shnum());
880 return (*this->map_to_relocatable_relocs_
)[reloc_shndx
];
883 // Layout sections whose layout was deferred while waiting for
884 // input files from a plugin.
886 layout_deferred_sections(Layout
* layout
)
887 { this->do_layout_deferred_sections(layout
); }
889 // Return the index of the first incremental relocation for symbol SYMNDX.
891 do_get_incremental_reloc_base(unsigned int symndx
) const
892 { return this->reloc_bases_
[symndx
]; }
894 // Return the number of incremental relocations for symbol SYMNDX.
896 do_get_incremental_reloc_count(unsigned int symndx
) const
897 { return this->reloc_counts_
[symndx
]; }
900 // The output section to be used for each input section, indexed by
901 // the input section number. The output section is NULL if the
902 // input section is to be discarded.
903 typedef std::vector
<Output_section
*> Output_sections
;
905 // Read the relocs--implemented by child class.
907 do_read_relocs(Read_relocs_data
*) = 0;
909 // Process the relocs--implemented by child class.
911 do_gc_process_relocs(Symbol_table
*, Layout
*, Read_relocs_data
*) = 0;
913 // Scan the relocs--implemented by child class.
915 do_scan_relocs(Symbol_table
*, Layout
*, Read_relocs_data
*) = 0;
917 // Return the number of local symbols--implemented by child class.
919 do_local_symbol_count() const = 0;
921 // Count local symbols--implemented by child class.
923 do_count_local_symbols(Stringpool_template
<char>*,
924 Stringpool_template
<char>*) = 0;
926 // Finalize the local symbols. Set the output symbol table indexes
927 // for the local variables, and set the offset where local symbol
928 // information will be stored.
930 do_finalize_local_symbols(unsigned int, off_t
, Symbol_table
*) = 0;
932 // Set the output dynamic symbol table indexes for the local variables.
934 do_set_local_dynsym_indexes(unsigned int) = 0;
936 // Set the offset where local dynamic symbol information will be stored.
938 do_set_local_dynsym_offset(off_t
) = 0;
940 // Relocate the input sections and write out the local
941 // symbols--implemented by child class.
943 do_relocate(const Symbol_table
* symtab
, const Layout
*, Output_file
* of
) = 0;
945 // Set the offset of a section--implemented by child class.
947 do_set_section_offset(unsigned int shndx
, uint64_t off
) = 0;
949 // Layout sections whose layout was deferred while waiting for
950 // input files from a plugin--implemented by child class.
952 do_layout_deferred_sections(Layout
*) = 0;
954 // Given a section index, return the corresponding Output_section.
955 // The return value will be NULL if the section is not included in
958 do_output_section(unsigned int shndx
) const
960 gold_assert(shndx
< this->output_sections_
.size());
961 return this->output_sections_
[shndx
];
964 // Return the vector mapping input sections to output sections.
967 { return this->output_sections_
; }
969 const Output_sections
&
970 output_sections() const
971 { return this->output_sections_
; }
973 // Set the size of the relocatable relocs array.
975 size_relocatable_relocs()
977 this->map_to_relocatable_relocs_
=
978 new std::vector
<Relocatable_relocs
*>(this->shnum());
981 // Record that we must wait for the output sections to be written
982 // before applying relocations.
984 set_relocs_must_follow_section_writes()
985 { this->relocs_must_follow_section_writes_
= true; }
987 // Allocate the array for counting incremental relocations.
989 allocate_incremental_reloc_counts()
991 unsigned int nsyms
= this->do_get_global_symbols()->size();
992 this->reloc_counts_
= new unsigned int[nsyms
];
993 gold_assert(this->reloc_counts_
!= NULL
);
994 memset(this->reloc_counts_
, 0, nsyms
* sizeof(unsigned int));
997 // Record a relocation in this object referencing global symbol SYMNDX.
998 // Used for tracking incremental link information.
1000 count_incremental_reloc(unsigned int symndx
)
1002 unsigned int nsyms
= this->do_get_global_symbols()->size();
1003 gold_assert(symndx
< nsyms
);
1004 gold_assert(this->reloc_counts_
!= NULL
);
1005 ++this->reloc_counts_
[symndx
];
1008 // Finalize the incremental relocation information.
1010 finalize_incremental_relocs(Layout
* layout
);
1012 // Return the index of the next relocation to be written for global symbol
1013 // SYMNDX. Only valid after finalize_incremental_relocs() has been called.
1015 next_incremental_reloc_index(unsigned int symndx
)
1017 unsigned int nsyms
= this->do_get_global_symbols()->size();
1019 gold_assert(this->reloc_counts_
!= NULL
);
1020 gold_assert(this->reloc_bases_
!= NULL
);
1021 gold_assert(symndx
< nsyms
);
1023 unsigned int counter
= this->reloc_counts_
[symndx
]++;
1024 return this->reloc_bases_
[symndx
] + counter
;
1028 // Mapping from input sections to output section.
1029 Output_sections output_sections_
;
1030 // Mapping from input section index to the information recorded for
1031 // the relocations. This is only used for a relocatable link.
1032 std::vector
<Relocatable_relocs
*>* map_to_relocatable_relocs_
;
1033 // Mappings for merge sections. This is managed by the code in the
1035 Object_merge_map
* object_merge_map_
;
1036 // Whether we need to wait for output sections to be written before
1037 // we can apply relocations.
1038 bool relocs_must_follow_section_writes_
;
1039 // Used to store the relocs data computed by the Read_relocs pass.
1040 // Used during garbage collection of unused sections.
1041 Read_relocs_data
* rd_
;
1042 // Used to store the symbols data computed by the Read_symbols pass.
1043 // Again used during garbage collection when laying out referenced
1045 gold::Symbols_data
*sd_
;
1046 // Per-symbol counts of relocations, for incremental links.
1047 unsigned int* reloc_counts_
;
1048 // Per-symbol base indexes of relocations, for incremental links.
1049 unsigned int* reloc_bases_
;
1052 // This class is used to handle relocations against a section symbol
1053 // in an SHF_MERGE section. For such a symbol, we need to know the
1054 // addend of the relocation before we can determine the final value.
1055 // The addend gives us the location in the input section, and we can
1056 // determine how it is mapped to the output section. For a
1057 // non-section symbol, we apply the addend to the final value of the
1058 // symbol; that is done in finalize_local_symbols, and does not use
1062 class Merged_symbol_value
1065 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Value
;
1067 // We use a hash table to map offsets in the input section to output
1069 typedef Unordered_map
<section_offset_type
, Value
> Output_addresses
;
1071 Merged_symbol_value(Value input_value
, Value output_start_address
)
1072 : input_value_(input_value
), output_start_address_(output_start_address
),
1076 // Initialize the hash table.
1078 initialize_input_to_output_map(const Relobj
*, unsigned int input_shndx
);
1080 // Release the hash table to save space.
1082 free_input_to_output_map()
1083 { this->output_addresses_
.clear(); }
1085 // Get the output value corresponding to an addend. The object and
1086 // input section index are passed in because the caller will have
1087 // them; otherwise we could store them here.
1089 value(const Relobj
* object
, unsigned int input_shndx
, Value addend
) const
1091 // This is a relocation against a section symbol. ADDEND is the
1092 // offset in the section. The result should be the start of some
1093 // merge area. If the object file wants something else, it should
1094 // use a regular symbol rather than a section symbol.
1095 // Unfortunately, PR 6658 shows a case in which the object file
1096 // refers to the section symbol, but uses a negative ADDEND to
1097 // compensate for a PC relative reloc. We can't handle the
1098 // general case. However, we can handle the special case of a
1099 // negative addend, by assuming that it refers to the start of the
1100 // section. Of course, that means that we have to guess when
1101 // ADDEND is negative. It is normal to see a 32-bit value here
1102 // even when the template parameter size is 64, as 64-bit object
1103 // file formats have 32-bit relocations. We know this is a merge
1104 // section, so we know it has to fit into memory. So we assume
1105 // that we won't see a value larger than a large 32-bit unsigned
1106 // value. This will break objects with very very large merge
1107 // sections; they probably break in other ways anyhow.
1108 Value input_offset
= this->input_value_
;
1109 if (addend
< 0xffffff00)
1111 input_offset
+= addend
;
1114 typename
Output_addresses::const_iterator p
=
1115 this->output_addresses_
.find(input_offset
);
1116 if (p
!= this->output_addresses_
.end())
1117 return p
->second
+ addend
;
1119 return (this->value_from_output_section(object
, input_shndx
, input_offset
)
1124 // Get the output value for an input offset if we couldn't find it
1125 // in the hash table.
1127 value_from_output_section(const Relobj
*, unsigned int input_shndx
,
1128 Value input_offset
) const;
1130 // The value of the section symbol in the input file. This is
1131 // normally zero, but could in principle be something else.
1133 // The start address of this merged section in the output file.
1134 Value output_start_address_
;
1135 // A hash table which maps offsets in the input section to output
1136 // addresses. This only maps specific offsets, not all offsets.
1137 Output_addresses output_addresses_
;
1140 // This POD class is holds the value of a symbol. This is used for
1141 // local symbols, and for all symbols during relocation processing.
1142 // For special sections, such as SHF_MERGE sections, this calls a
1143 // function to get the final symbol value.
1149 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Value
;
1152 : output_symtab_index_(0), output_dynsym_index_(-1U), input_shndx_(0),
1153 is_ordinary_shndx_(false), is_section_symbol_(false),
1154 is_tls_symbol_(false), has_output_value_(true)
1155 { this->u_
.value
= 0; }
1157 // Get the value of this symbol. OBJECT is the object in which this
1158 // symbol is defined, and ADDEND is an addend to add to the value.
1159 template<bool big_endian
>
1161 value(const Sized_relobj
<size
, big_endian
>* object
, Value addend
) const
1163 if (this->has_output_value_
)
1164 return this->u_
.value
+ addend
;
1167 gold_assert(this->is_ordinary_shndx_
);
1168 return this->u_
.merged_symbol_value
->value(object
, this->input_shndx_
,
1173 // Set the value of this symbol in the output symbol table.
1175 set_output_value(Value value
)
1176 { this->u_
.value
= value
; }
1178 // For a section symbol in a merged section, we need more
1181 set_merged_symbol_value(Merged_symbol_value
<size
>* msv
)
1183 gold_assert(this->is_section_symbol_
);
1184 this->has_output_value_
= false;
1185 this->u_
.merged_symbol_value
= msv
;
1188 // Initialize the input to output map for a section symbol in a
1189 // merged section. We also initialize the value of a non-section
1190 // symbol in a merged section.
1192 initialize_input_to_output_map(const Relobj
* object
)
1194 if (!this->has_output_value_
)
1196 gold_assert(this->is_section_symbol_
&& this->is_ordinary_shndx_
);
1197 Merged_symbol_value
<size
>* msv
= this->u_
.merged_symbol_value
;
1198 msv
->initialize_input_to_output_map(object
, this->input_shndx_
);
1202 // Free the input to output map for a section symbol in a merged
1205 free_input_to_output_map()
1207 if (!this->has_output_value_
)
1208 this->u_
.merged_symbol_value
->free_input_to_output_map();
1211 // Set the value of the symbol from the input file. This is only
1212 // called by count_local_symbols, to communicate the value to
1213 // finalize_local_symbols.
1215 set_input_value(Value value
)
1216 { this->u_
.value
= value
; }
1218 // Return the input value. This is only called by
1219 // finalize_local_symbols and (in special cases) relocate_section.
1222 { return this->u_
.value
; }
1224 // Return whether we have set the index in the output symbol table
1227 is_output_symtab_index_set() const
1229 return (this->output_symtab_index_
!= 0
1230 && this->output_symtab_index_
!= -2U);
1233 // Return whether this symbol may be discarded from the normal
1236 may_be_discarded_from_output_symtab() const
1238 gold_assert(!this->is_output_symtab_index_set());
1239 return this->output_symtab_index_
!= -2U;
1242 // Return whether this symbol has an entry in the output symbol
1245 has_output_symtab_entry() const
1247 gold_assert(this->is_output_symtab_index_set());
1248 return this->output_symtab_index_
!= -1U;
1251 // Return the index in the output symbol table.
1253 output_symtab_index() const
1255 gold_assert(this->is_output_symtab_index_set()
1256 && this->output_symtab_index_
!= -1U);
1257 return this->output_symtab_index_
;
1260 // Set the index in the output symbol table.
1262 set_output_symtab_index(unsigned int i
)
1264 gold_assert(!this->is_output_symtab_index_set());
1265 gold_assert(i
!= 0 && i
!= -1U && i
!= -2U);
1266 this->output_symtab_index_
= i
;
1269 // Record that this symbol should not go into the output symbol
1272 set_no_output_symtab_entry()
1274 gold_assert(this->output_symtab_index_
== 0);
1275 this->output_symtab_index_
= -1U;
1278 // Record that this symbol must go into the output symbol table,
1279 // because it there is a relocation that uses it.
1281 set_must_have_output_symtab_entry()
1283 gold_assert(!this->is_output_symtab_index_set());
1284 this->output_symtab_index_
= -2U;
1287 // Set the index in the output dynamic symbol table.
1289 set_needs_output_dynsym_entry()
1291 gold_assert(!this->is_section_symbol());
1292 this->output_dynsym_index_
= 0;
1295 // Return whether this symbol should go into the dynamic symbol
1298 needs_output_dynsym_entry() const
1300 return this->output_dynsym_index_
!= -1U;
1303 // Return whether this symbol has an entry in the dynamic symbol
1306 has_output_dynsym_entry() const
1308 gold_assert(this->output_dynsym_index_
!= 0);
1309 return this->output_dynsym_index_
!= -1U;
1312 // Record that this symbol should go into the dynamic symbol table.
1314 set_output_dynsym_index(unsigned int i
)
1316 gold_assert(this->output_dynsym_index_
== 0);
1317 gold_assert(i
!= 0 && i
!= -1U);
1318 this->output_dynsym_index_
= i
;
1321 // Return the index in the output dynamic symbol table.
1323 output_dynsym_index() const
1325 gold_assert(this->output_dynsym_index_
!= 0
1326 && this->output_dynsym_index_
!= -1U);
1327 return this->output_dynsym_index_
;
1330 // Set the index of the input section in the input file.
1332 set_input_shndx(unsigned int i
, bool is_ordinary
)
1334 this->input_shndx_
= i
;
1335 // input_shndx_ field is a bitfield, so make sure that the value
1337 gold_assert(this->input_shndx_
== i
);
1338 this->is_ordinary_shndx_
= is_ordinary
;
1341 // Return the index of the input section in the input file.
1343 input_shndx(bool* is_ordinary
) const
1345 *is_ordinary
= this->is_ordinary_shndx_
;
1346 return this->input_shndx_
;
1349 // Whether this is a section symbol.
1351 is_section_symbol() const
1352 { return this->is_section_symbol_
; }
1354 // Record that this is a section symbol.
1356 set_is_section_symbol()
1358 gold_assert(!this->needs_output_dynsym_entry());
1359 this->is_section_symbol_
= true;
1362 // Record that this is a TLS symbol.
1365 { this->is_tls_symbol_
= true; }
1367 // Return TRUE if this is a TLS symbol.
1369 is_tls_symbol() const
1370 { return this->is_tls_symbol_
; }
1373 // The index of this local symbol in the output symbol table. This
1374 // will be 0 if no value has been assigned yet, and the symbol may
1375 // be omitted. This will be -1U if the symbol should not go into
1376 // the symbol table. This will be -2U if the symbol must go into
1377 // the symbol table, but no index has been assigned yet.
1378 unsigned int output_symtab_index_
;
1379 // The index of this local symbol in the dynamic symbol table. This
1380 // will be -1U if the symbol should not go into the symbol table.
1381 unsigned int output_dynsym_index_
;
1382 // The section index in the input file in which this symbol is
1384 unsigned int input_shndx_
: 28;
1385 // Whether the section index is an ordinary index, not a special
1387 bool is_ordinary_shndx_
: 1;
1388 // Whether this is a STT_SECTION symbol.
1389 bool is_section_symbol_
: 1;
1390 // Whether this is a STT_TLS symbol.
1391 bool is_tls_symbol_
: 1;
1392 // Whether this symbol has a value for the output file. This is
1393 // normally set to true during Layout::finalize, by
1394 // finalize_local_symbols. It will be false for a section symbol in
1395 // a merge section, as for such symbols we can not determine the
1396 // value to use in a relocation until we see the addend.
1397 bool has_output_value_
: 1;
1400 // This is used if has_output_value_ is true. Between
1401 // count_local_symbols and finalize_local_symbols, this is the
1402 // value in the input file. After finalize_local_symbols, it is
1403 // the value in the output file.
1405 // This is used if has_output_value_ is false. It points to the
1406 // information we need to get the value for a merge section.
1407 Merged_symbol_value
<size
>* merged_symbol_value
;
1411 // A GOT offset list. A symbol may have more than one GOT offset
1412 // (e.g., when mixing modules compiled with two different TLS models),
1413 // but will usually have at most one. GOT_TYPE identifies the type of
1414 // GOT entry; its values are specific to each target.
1416 class Got_offset_list
1420 : got_type_(-1U), got_offset_(0), got_next_(NULL
)
1423 Got_offset_list(unsigned int got_type
, unsigned int got_offset
)
1424 : got_type_(got_type
), got_offset_(got_offset
), got_next_(NULL
)
1429 if (this->got_next_
!= NULL
)
1431 delete this->got_next_
;
1432 this->got_next_
= NULL
;
1436 // Initialize the fields to their default values.
1440 this->got_type_
= -1U;
1441 this->got_offset_
= 0;
1442 this->got_next_
= NULL
;
1445 // Set the offset for the GOT entry of type GOT_TYPE.
1447 set_offset(unsigned int got_type
, unsigned int got_offset
)
1449 if (this->got_type_
== -1U)
1451 this->got_type_
= got_type
;
1452 this->got_offset_
= got_offset
;
1456 for (Got_offset_list
* g
= this; g
!= NULL
; g
= g
->got_next_
)
1458 if (g
->got_type_
== got_type
)
1460 g
->got_offset_
= got_offset
;
1464 Got_offset_list
* g
= new Got_offset_list(got_type
, got_offset
);
1465 g
->got_next_
= this->got_next_
;
1466 this->got_next_
= g
;
1470 // Return the offset for a GOT entry of type GOT_TYPE.
1472 get_offset(unsigned int got_type
) const
1474 for (const Got_offset_list
* g
= this; g
!= NULL
; g
= g
->got_next_
)
1476 if (g
->got_type_
== got_type
)
1477 return g
->got_offset_
;
1482 // Return a pointer to the list, or NULL if the list is empty.
1483 const Got_offset_list
*
1486 if (this->got_type_
== -1U)
1491 // Loop over all GOT offset entries, applying the function F to each.
1492 template<typename F
>
1494 for_all_got_offsets(F f
) const
1496 if (this->got_type_
== -1U)
1498 for (const Got_offset_list
* g
= this; g
!= NULL
; g
= g
->got_next_
)
1499 f(g
->got_type_
, g
->got_offset_
);
1503 unsigned int got_type_
;
1504 unsigned int got_offset_
;
1505 Got_offset_list
* got_next_
;
1508 // This type is used to modify relocations for -fsplit-stack. It is
1509 // indexed by relocation index, and means that the relocation at that
1510 // index should use the symbol from the vector, rather than the one
1511 // indicated by the relocation.
1513 class Reloc_symbol_changes
1516 Reloc_symbol_changes(size_t count
)
1521 set(size_t i
, Symbol
* sym
)
1522 { this->vec_
[i
] = sym
; }
1525 operator[](size_t i
) const
1526 { return this->vec_
[i
]; }
1529 std::vector
<Symbol
*> vec_
;
1532 // Type for mapping section index to uncompressed size.
1534 typedef std::map
<unsigned int, section_size_type
> Compressed_section_map
;
1536 // A regular object file. This is size and endian specific.
1538 template<int size
, bool big_endian
>
1539 class Sized_relobj
: public Relobj
1542 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Address
;
1543 typedef std::vector
<Symbol
*> Symbols
;
1544 typedef std::vector
<Symbol_value
<size
> > Local_values
;
1546 static const Address invalid_address
= static_cast<Address
>(0) - 1;
1548 Sized_relobj(const std::string
& name
, Input_file
* input_file
, off_t offset
,
1549 const typename
elfcpp::Ehdr
<size
, big_endian
>&);
1553 // Checks if the offset of input section SHNDX within its output
1554 // section is invalid.
1556 is_output_section_offset_invalid(unsigned int shndx
) const
1557 { return this->get_output_section_offset(shndx
) == invalid_address
; }
1559 // Set up the object file based on TARGET.
1562 { this->do_setup(); }
1564 // Return the number of symbols. This is only valid after
1565 // Object::add_symbols has been called.
1567 symbol_count() const
1568 { return this->local_symbol_count_
+ this->symbols_
.size(); }
1570 // If SYM is the index of a global symbol in the object file's
1571 // symbol table, return the Symbol object. Otherwise, return NULL.
1573 global_symbol(unsigned int sym
) const
1575 if (sym
>= this->local_symbol_count_
)
1577 gold_assert(sym
- this->local_symbol_count_
< this->symbols_
.size());
1578 return this->symbols_
[sym
- this->local_symbol_count_
];
1583 // Return the section index of symbol SYM. Set *VALUE to its value
1584 // in the object file. Set *IS_ORDINARY if this is an ordinary
1585 // section index, not a special code between SHN_LORESERVE and
1586 // SHN_HIRESERVE. Note that for a symbol which is not defined in
1587 // this object file, this will set *VALUE to 0 and return SHN_UNDEF;
1588 // it will not return the final value of the symbol in the link.
1590 symbol_section_and_value(unsigned int sym
, Address
* value
, bool* is_ordinary
);
1592 // Return a pointer to the Symbol_value structure which holds the
1593 // value of a local symbol.
1594 const Symbol_value
<size
>*
1595 local_symbol(unsigned int sym
) const
1597 gold_assert(sym
< this->local_values_
.size());
1598 return &this->local_values_
[sym
];
1601 // Return the index of local symbol SYM in the ordinary symbol
1602 // table. A value of -1U means that the symbol is not being output.
1604 symtab_index(unsigned int sym
) const
1606 gold_assert(sym
< this->local_values_
.size());
1607 return this->local_values_
[sym
].output_symtab_index();
1610 // Return the index of local symbol SYM in the dynamic symbol
1611 // table. A value of -1U means that the symbol is not being output.
1613 dynsym_index(unsigned int sym
) const
1615 gold_assert(sym
< this->local_values_
.size());
1616 return this->local_values_
[sym
].output_dynsym_index();
1619 // Return the input section index of local symbol SYM.
1621 local_symbol_input_shndx(unsigned int sym
, bool* is_ordinary
) const
1623 gold_assert(sym
< this->local_values_
.size());
1624 return this->local_values_
[sym
].input_shndx(is_ordinary
);
1627 // Record that local symbol SYM must be in the output symbol table.
1629 set_must_have_output_symtab_entry(unsigned int sym
)
1631 gold_assert(sym
< this->local_values_
.size());
1632 this->local_values_
[sym
].set_must_have_output_symtab_entry();
1635 // Record that local symbol SYM needs a dynamic symbol entry.
1637 set_needs_output_dynsym_entry(unsigned int sym
)
1639 gold_assert(sym
< this->local_values_
.size());
1640 this->local_values_
[sym
].set_needs_output_dynsym_entry();
1643 // Return whether the local symbol SYMNDX has a GOT offset.
1644 // For TLS symbols, the GOT entry will hold its tp-relative offset.
1646 local_has_got_offset(unsigned int symndx
, unsigned int got_type
) const
1648 Local_got_offsets::const_iterator p
=
1649 this->local_got_offsets_
.find(symndx
);
1650 return (p
!= this->local_got_offsets_
.end()
1651 && p
->second
->get_offset(got_type
) != -1U);
1654 // Return the GOT offset of the local symbol SYMNDX.
1656 local_got_offset(unsigned int symndx
, unsigned int got_type
) const
1658 Local_got_offsets::const_iterator p
=
1659 this->local_got_offsets_
.find(symndx
);
1660 gold_assert(p
!= this->local_got_offsets_
.end());
1661 unsigned int off
= p
->second
->get_offset(got_type
);
1662 gold_assert(off
!= -1U);
1666 // Set the GOT offset of the local symbol SYMNDX to GOT_OFFSET.
1668 set_local_got_offset(unsigned int symndx
, unsigned int got_type
,
1669 unsigned int got_offset
)
1671 Local_got_offsets::const_iterator p
=
1672 this->local_got_offsets_
.find(symndx
);
1673 if (p
!= this->local_got_offsets_
.end())
1674 p
->second
->set_offset(got_type
, got_offset
);
1677 Got_offset_list
* g
= new Got_offset_list(got_type
, got_offset
);
1678 std::pair
<Local_got_offsets::iterator
, bool> ins
=
1679 this->local_got_offsets_
.insert(std::make_pair(symndx
, g
));
1680 gold_assert(ins
.second
);
1684 // Return the GOT offset list for the local symbol SYMNDX.
1685 const Got_offset_list
*
1686 local_got_offset_list(unsigned int symndx
) const
1688 Local_got_offsets::const_iterator p
=
1689 this->local_got_offsets_
.find(symndx
);
1690 if (p
== this->local_got_offsets_
.end())
1695 // Get the offset of input section SHNDX within its output section.
1696 // This is -1 if the input section requires a special mapping, such
1697 // as a merge section. The output section can be found in the
1698 // output_sections_ field of the parent class Relobj.
1700 get_output_section_offset(unsigned int shndx
) const
1702 gold_assert(shndx
< this->section_offsets_
.size());
1703 return this->section_offsets_
[shndx
];
1706 // Return the name of the symbol that spans the given offset in the
1707 // specified section in this object. This is used only for error
1708 // messages and is not particularly efficient.
1710 get_symbol_location_info(unsigned int shndx
, off_t offset
,
1711 Symbol_location_info
* info
);
1713 // Look for a kept section corresponding to the given discarded section,
1714 // and return its output address. This is used only for relocations in
1715 // debugging sections.
1717 map_to_kept_section(unsigned int shndx
, bool* found
) const;
1724 // Read the symbols.
1726 do_read_symbols(Read_symbols_data
*);
1728 // Return the number of local symbols.
1730 do_local_symbol_count() const
1731 { return this->local_symbol_count_
; }
1733 // Lay out the input sections.
1735 do_layout(Symbol_table
*, Layout
*, Read_symbols_data
*);
1737 // Layout sections whose layout was deferred while waiting for
1738 // input files from a plugin.
1740 do_layout_deferred_sections(Layout
*);
1742 // Add the symbols to the symbol table.
1744 do_add_symbols(Symbol_table
*, Read_symbols_data
*, Layout
*);
1746 Archive::Should_include
1747 do_should_include_member(Symbol_table
* symtab
, Layout
*, Read_symbols_data
*,
1752 do_read_relocs(Read_relocs_data
*);
1754 // Process the relocs to find list of referenced sections. Used only
1755 // during garbage collection.
1757 do_gc_process_relocs(Symbol_table
*, Layout
*, Read_relocs_data
*);
1759 // Scan the relocs and adjust the symbol table.
1761 do_scan_relocs(Symbol_table
*, Layout
*, Read_relocs_data
*);
1763 // Count the local symbols.
1765 do_count_local_symbols(Stringpool_template
<char>*,
1766 Stringpool_template
<char>*);
1768 // Finalize the local symbols.
1770 do_finalize_local_symbols(unsigned int, off_t
, Symbol_table
*);
1772 // Set the offset where local dynamic symbol information will be stored.
1774 do_set_local_dynsym_indexes(unsigned int);
1776 // Set the offset where local dynamic symbol information will be stored.
1778 do_set_local_dynsym_offset(off_t
);
1780 // Relocate the input sections and write out the local symbols.
1782 do_relocate(const Symbol_table
* symtab
, const Layout
*, Output_file
* of
);
1784 // Get the size of a section.
1786 do_section_size(unsigned int shndx
)
1787 { return this->elf_file_
.section_size(shndx
); }
1789 // Get the name of a section.
1791 do_section_name(unsigned int shndx
)
1792 { return this->elf_file_
.section_name(shndx
); }
1794 // Return the location of the contents of a section.
1796 do_section_contents(unsigned int shndx
)
1797 { return this->elf_file_
.section_contents(shndx
); }
1799 // Return section flags.
1801 do_section_flags(unsigned int shndx
);
1803 // Return section entsize.
1805 do_section_entsize(unsigned int shndx
);
1807 // Return section address.
1809 do_section_address(unsigned int shndx
)
1810 { return this->elf_file_
.section_addr(shndx
); }
1812 // Return section type.
1814 do_section_type(unsigned int shndx
)
1815 { return this->elf_file_
.section_type(shndx
); }
1817 // Return the section link field.
1819 do_section_link(unsigned int shndx
)
1820 { return this->elf_file_
.section_link(shndx
); }
1822 // Return the section info field.
1824 do_section_info(unsigned int shndx
)
1825 { return this->elf_file_
.section_info(shndx
); }
1827 // Return the section alignment.
1829 do_section_addralign(unsigned int shndx
)
1830 { return this->elf_file_
.section_addralign(shndx
); }
1832 // Return the Xindex structure to use.
1834 do_initialize_xindex();
1836 // Get symbol counts.
1838 do_get_global_symbol_counts(const Symbol_table
*, size_t*, size_t*) const;
1840 // Get the global symbols.
1842 do_get_global_symbols() const
1843 { return &this->symbols_
; }
1845 // Get the offset of a section.
1847 do_output_section_offset(unsigned int shndx
) const
1849 Address off
= this->get_output_section_offset(shndx
);
1850 if (off
== invalid_address
)
1855 // Set the offset of a section.
1857 do_set_section_offset(unsigned int shndx
, uint64_t off
)
1859 gold_assert(shndx
< this->section_offsets_
.size());
1860 this->section_offsets_
[shndx
] =
1861 (off
== static_cast<uint64_t>(-1)
1863 : convert_types
<Address
, uint64_t>(off
));
1866 // Adjust a section index if necessary.
1868 adjust_shndx(unsigned int shndx
)
1870 if (shndx
>= elfcpp::SHN_LORESERVE
)
1871 shndx
+= this->elf_file_
.large_shndx_offset();
1875 // Initialize input to output maps for section symbols in merged
1878 initialize_input_to_output_maps();
1880 // Free the input to output maps for section symbols in merged
1883 free_input_to_output_maps();
1885 // Return symbol table section index.
1887 symtab_shndx() const
1888 { return this->symtab_shndx_
; }
1890 // Allow a child class to access the ELF file.
1891 elfcpp::Elf_file
<size
, big_endian
, Object
>*
1893 { return &this->elf_file_
; }
1895 // Allow a child class to access the local values.
1898 { return &this->local_values_
; }
1900 // Views and sizes when relocating.
1903 unsigned char* view
;
1904 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
;
1906 section_size_type view_size
;
1907 bool is_input_output_view
;
1908 bool is_postprocessing_view
;
1911 typedef std::vector
<View_size
> Views
;
1913 // This may be overriden by a child class.
1915 do_relocate_sections(const Symbol_table
* symtab
, const Layout
* layout
,
1916 const unsigned char* pshdrs
, Output_file
* of
,
1919 // Allow a child to set output local symbol count.
1921 set_output_local_symbol_count(unsigned int value
)
1922 { this->output_local_symbol_count_
= value
; }
1924 // Return TRUE if the section is a compressed debug section, and set
1925 // *UNCOMPRESSED_SIZE to the size of the uncompressed data.
1927 do_section_is_compressed(unsigned int shndx
,
1928 section_size_type
* uncompressed_size
) const
1930 if (this->compressed_sections_
== NULL
)
1932 Compressed_section_map::const_iterator p
=
1933 this->compressed_sections_
->find(shndx
);
1934 if (p
!= this->compressed_sections_
->end())
1936 if (uncompressed_size
!= NULL
)
1937 *uncompressed_size
= p
->second
;
1945 typedef Sized_relobj
<size
, big_endian
> This
;
1946 static const int ehdr_size
= elfcpp::Elf_sizes
<size
>::ehdr_size
;
1947 static const int shdr_size
= elfcpp::Elf_sizes
<size
>::shdr_size
;
1948 static const int sym_size
= elfcpp::Elf_sizes
<size
>::sym_size
;
1949 typedef elfcpp::Shdr
<size
, big_endian
> Shdr
;
1951 // To keep track of discarded comdat sections, we need to map a member
1952 // section index to the object and section index of the corresponding
1954 struct Kept_comdat_section
1956 Kept_comdat_section(Relobj
* a_object
, unsigned int a_shndx
)
1957 : object(a_object
), shndx(a_shndx
)
1962 typedef std::map
<unsigned int, Kept_comdat_section
>
1963 Kept_comdat_section_table
;
1965 // Find the SHT_SYMTAB section, given the section headers.
1967 find_symtab(const unsigned char* pshdrs
);
1969 // Return whether SHDR has the right flags for a GNU style exception
1972 check_eh_frame_flags(const elfcpp::Shdr
<size
, big_endian
>* shdr
) const;
1974 // Return whether there is a section named .eh_frame which might be
1975 // a GNU style exception frame section.
1977 find_eh_frame(const unsigned char* pshdrs
, const char* names
,
1978 section_size_type names_size
) const;
1980 // Whether to include a section group in the link.
1982 include_section_group(Symbol_table
*, Layout
*, unsigned int, const char*,
1983 const unsigned char*, const char *, section_size_type
,
1984 std::vector
<bool>*);
1986 // Whether to include a linkonce section in the link.
1988 include_linkonce_section(Layout
*, unsigned int, const char*,
1989 const elfcpp::Shdr
<size
, big_endian
>&);
1991 // Layout an input section.
1993 layout_section(Layout
* layout
, unsigned int shndx
, const char* name
,
1994 typename
This::Shdr
& shdr
, unsigned int reloc_shndx
,
1995 unsigned int reloc_type
);
1997 // Write section data to the output file. Record the views and
1998 // sizes in VIEWS for use when relocating.
2000 write_sections(const unsigned char* pshdrs
, Output_file
*, Views
*);
2002 // Relocate the sections in the output file.
2004 relocate_sections(const Symbol_table
* symtab
, const Layout
* layout
,
2005 const unsigned char* pshdrs
, Output_file
* of
,
2007 { this->do_relocate_sections(symtab
, layout
, pshdrs
, of
, pviews
); }
2009 // Scan the input relocations for --emit-relocs.
2011 emit_relocs_scan(Symbol_table
*, Layout
*, const unsigned char* plocal_syms
,
2012 const Read_relocs_data::Relocs_list::iterator
&);
2014 // Scan the input relocations for --emit-relocs, templatized on the
2015 // type of the relocation section.
2016 template<int sh_type
>
2018 emit_relocs_scan_reltype(Symbol_table
*, Layout
*,
2019 const unsigned char* plocal_syms
,
2020 const Read_relocs_data::Relocs_list::iterator
&,
2021 Relocatable_relocs
*);
2023 // Emit the relocs for --emit-relocs.
2025 emit_relocs(const Relocate_info
<size
, big_endian
>*, unsigned int,
2026 unsigned int sh_type
, const unsigned char* prelocs
,
2027 size_t reloc_count
, Output_section
*, Address output_offset
,
2028 unsigned char* view
, Address address
,
2029 section_size_type view_size
,
2030 unsigned char* reloc_view
, section_size_type reloc_view_size
);
2032 // Emit the relocs for --emit-relocs, templatized on the type of the
2033 // relocation section.
2034 template<int sh_type
>
2036 emit_relocs_reltype(const Relocate_info
<size
, big_endian
>*, unsigned int,
2037 const unsigned char* prelocs
, size_t reloc_count
,
2038 Output_section
*, Address output_offset
,
2039 unsigned char* view
, Address address
,
2040 section_size_type view_size
,
2041 unsigned char* reloc_view
,
2042 section_size_type reloc_view_size
);
2044 // Scan the input relocations for --incremental.
2046 incremental_relocs_scan(const Read_relocs_data::Relocs_list::iterator
&);
2048 // Scan the input relocations for --incremental, templatized on the
2049 // type of the relocation section.
2050 template<int sh_type
>
2052 incremental_relocs_scan_reltype(
2053 const Read_relocs_data::Relocs_list::iterator
&);
2056 incremental_relocs_write(const Relocate_info
<size
, big_endian
>*,
2057 unsigned int sh_type
,
2058 const unsigned char* prelocs
,
2061 Address output_offset
,
2064 template<int sh_type
>
2066 incremental_relocs_write_reltype(const Relocate_info
<size
, big_endian
>*,
2067 const unsigned char* prelocs
,
2070 Address output_offset
,
2073 // A type shared by split_stack_adjust_reltype and find_functions.
2074 typedef std::map
<section_offset_type
, section_size_type
> Function_offsets
;
2076 // Check for -fsplit-stack routines calling non-split-stack routines.
2078 split_stack_adjust(const Symbol_table
*, const unsigned char* pshdrs
,
2079 unsigned int sh_type
, unsigned int shndx
,
2080 const unsigned char* prelocs
, size_t reloc_count
,
2081 unsigned char* view
, section_size_type view_size
,
2082 Reloc_symbol_changes
** reloc_map
);
2084 template<int sh_type
>
2086 split_stack_adjust_reltype(const Symbol_table
*, const unsigned char* pshdrs
,
2087 unsigned int shndx
, const unsigned char* prelocs
,
2088 size_t reloc_count
, unsigned char* view
,
2089 section_size_type view_size
,
2090 Reloc_symbol_changes
** reloc_map
);
2092 // Find all functions in a section.
2094 find_functions(const unsigned char* pshdrs
, unsigned int shndx
,
2097 // Write out the local symbols.
2099 write_local_symbols(Output_file
*,
2100 const Stringpool_template
<char>*,
2101 const Stringpool_template
<char>*,
2102 Output_symtab_xindex
*,
2103 Output_symtab_xindex
*);
2105 // Clear the local symbol information.
2107 clear_local_symbols()
2109 this->local_values_
.clear();
2110 this->local_got_offsets_
.clear();
2113 // Record a mapping from discarded section SHNDX to the corresponding
2116 set_kept_comdat_section(unsigned int shndx
, Relobj
* kept_object
,
2117 unsigned int kept_shndx
)
2119 Kept_comdat_section
kept(kept_object
, kept_shndx
);
2120 this->kept_comdat_sections_
.insert(std::make_pair(shndx
, kept
));
2123 // Find the kept section corresponding to the discarded section
2124 // SHNDX. Return true if found.
2126 get_kept_comdat_section(unsigned int shndx
, Relobj
** kept_object
,
2127 unsigned int* kept_shndx
) const
2129 typename
Kept_comdat_section_table::const_iterator p
=
2130 this->kept_comdat_sections_
.find(shndx
);
2131 if (p
== this->kept_comdat_sections_
.end())
2133 *kept_object
= p
->second
.object
;
2134 *kept_shndx
= p
->second
.shndx
;
2138 // The GOT offsets of local symbols. This map also stores GOT offsets
2139 // for tp-relative offsets for TLS symbols.
2140 typedef Unordered_map
<unsigned int, Got_offset_list
*> Local_got_offsets
;
2142 // The TLS GOT offsets of local symbols. The map stores the offsets
2143 // for either a single GOT entry that holds the module index of a TLS
2144 // symbol, or a pair of GOT entries containing the module index and
2145 // dtv-relative offset.
2146 struct Tls_got_entry
2148 Tls_got_entry(int got_offset
, bool have_pair
)
2149 : got_offset_(got_offset
),
2150 have_pair_(have_pair
)
2155 typedef Unordered_map
<unsigned int, Tls_got_entry
> Local_tls_got_offsets
;
2157 // Saved information for sections whose layout was deferred.
2158 struct Deferred_layout
2160 static const int shdr_size
= elfcpp::Elf_sizes
<size
>::shdr_size
;
2161 Deferred_layout(unsigned int shndx
, const char* name
,
2162 const unsigned char* pshdr
,
2163 unsigned int reloc_shndx
, unsigned int reloc_type
)
2164 : shndx_(shndx
), name_(name
), reloc_shndx_(reloc_shndx
),
2165 reloc_type_(reloc_type
)
2167 memcpy(this->shdr_data_
, pshdr
, shdr_size
);
2169 unsigned int shndx_
;
2171 unsigned int reloc_shndx_
;
2172 unsigned int reloc_type_
;
2173 unsigned char shdr_data_
[shdr_size
];
2176 // General access to the ELF file.
2177 elfcpp::Elf_file
<size
, big_endian
, Object
> elf_file_
;
2178 // Index of SHT_SYMTAB section.
2179 unsigned int symtab_shndx_
;
2180 // The number of local symbols.
2181 unsigned int local_symbol_count_
;
2182 // The number of local symbols which go into the output file.
2183 unsigned int output_local_symbol_count_
;
2184 // The number of local symbols which go into the output file's dynamic
2186 unsigned int output_local_dynsym_count_
;
2187 // The entries in the symbol table for the external symbols.
2189 // Number of symbols defined in object file itself.
2190 size_t defined_count_
;
2191 // File offset for local symbols.
2192 off_t local_symbol_offset_
;
2193 // File offset for local dynamic symbols.
2194 off_t local_dynsym_offset_
;
2195 // Values of local symbols.
2196 Local_values local_values_
;
2197 // GOT offsets for local non-TLS symbols, and tp-relative offsets
2198 // for TLS symbols, indexed by symbol number.
2199 Local_got_offsets local_got_offsets_
;
2200 // For each input section, the offset of the input section in its
2201 // output section. This is INVALID_ADDRESS if the input section requires a
2203 std::vector
<Address
> section_offsets_
;
2204 // Table mapping discarded comdat sections to corresponding kept sections.
2205 Kept_comdat_section_table kept_comdat_sections_
;
2206 // Whether this object has a GNU style .eh_frame section.
2208 // If this object has a GNU style .eh_frame section that is discarded in
2209 // output, record the index here. Otherwise it is -1U.
2210 unsigned int discarded_eh_frame_shndx_
;
2211 // The list of sections whose layout was deferred.
2212 std::vector
<Deferred_layout
> deferred_layout_
;
2213 // The list of relocation sections whose layout was deferred.
2214 std::vector
<Deferred_layout
> deferred_layout_relocs_
;
2215 // For compressed debug sections, map section index to uncompressed size.
2216 Compressed_section_map
* compressed_sections_
;
2219 // A class to manage the list of all objects.
2225 : relobj_list_(), dynobj_list_(), sonames_(), cref_(NULL
)
2228 // The type of the list of input relocateable objects.
2229 typedef std::vector
<Relobj
*> Relobj_list
;
2230 typedef Relobj_list::const_iterator Relobj_iterator
;
2232 // The type of the list of input dynamic objects.
2233 typedef std::vector
<Dynobj
*> Dynobj_list
;
2234 typedef Dynobj_list::const_iterator Dynobj_iterator
;
2236 // Add an object to the list. Return true if all is well, or false
2237 // if this object should be ignored.
2239 add_object(Object
*);
2241 // Start processing an archive.
2243 archive_start(Archive
*);
2245 // Stop processing an archive.
2247 archive_stop(Archive
*);
2249 // For each dynamic object, check whether we've seen all of its
2250 // explicit dependencies.
2252 check_dynamic_dependencies() const;
2254 // Return whether an object was found in the system library
2257 found_in_system_library_directory(const Object
*) const;
2259 // Print symbol counts.
2261 print_symbol_counts(const Symbol_table
*) const;
2263 // Print a cross reference table.
2265 print_cref(const Symbol_table
*, FILE*) const;
2267 // Iterate over all regular objects.
2270 relobj_begin() const
2271 { return this->relobj_list_
.begin(); }
2275 { return this->relobj_list_
.end(); }
2277 // Iterate over all dynamic objects.
2280 dynobj_begin() const
2281 { return this->dynobj_list_
.begin(); }
2285 { return this->dynobj_list_
.end(); }
2287 // Return whether we have seen any dynamic objects.
2290 { return !this->dynobj_list_
.empty(); }
2292 // Return the number of non dynamic objects.
2294 number_of_relobjs() const
2295 { return this->relobj_list_
.size(); }
2297 // Return the number of input objects.
2299 number_of_input_objects() const
2300 { return this->relobj_list_
.size() + this->dynobj_list_
.size(); }
2303 Input_objects(const Input_objects
&);
2304 Input_objects
& operator=(const Input_objects
&);
2306 // The list of ordinary objects included in the link.
2307 Relobj_list relobj_list_
;
2308 // The list of dynamic objects included in the link.
2309 Dynobj_list dynobj_list_
;
2310 // SONAMEs that we have seen.
2311 Unordered_set
<std::string
> sonames_
;
2312 // Manage cross-references if requested.
2316 // Some of the information we pass to the relocation routines. We
2317 // group this together to avoid passing a dozen different arguments.
2319 template<int size
, bool big_endian
>
2320 struct Relocate_info
2323 const Symbol_table
* symtab
;
2325 const Layout
* layout
;
2326 // Object being relocated.
2327 Sized_relobj
<size
, big_endian
>* object
;
2328 // Section index of relocation section.
2329 unsigned int reloc_shndx
;
2330 // Section header of relocation section.
2331 const unsigned char* reloc_shdr
;
2332 // Section index of section being relocated.
2333 unsigned int data_shndx
;
2334 // Section header of data section.
2335 const unsigned char* data_shdr
;
2337 // Return a string showing the location of a relocation. This is
2338 // only used for error messages.
2340 location(size_t relnum
, off_t reloffset
) const;
2343 // This is used to represent a section in an object and is used as the
2344 // key type for various section maps.
2345 typedef std::pair
<Object
*, unsigned int> Section_id
;
2347 // This is similar to Section_id but is used when the section
2348 // pointers are const.
2349 typedef std::pair
<const Object
*, unsigned int> Const_section_id
;
2351 // The hash value is based on the address of an object in memory during
2352 // linking. It is okay to use this for looking up sections but never use
2353 // this in an unordered container that we want to traverse in a repeatable
2356 struct Section_id_hash
2358 size_t operator()(const Section_id
& loc
) const
2359 { return reinterpret_cast<uintptr_t>(loc
.first
) ^ loc
.second
; }
2362 struct Const_section_id_hash
2364 size_t operator()(const Const_section_id
& loc
) const
2365 { return reinterpret_cast<uintptr_t>(loc
.first
) ^ loc
.second
; }
2368 // Return whether INPUT_FILE contains an ELF object start at file
2369 // offset OFFSET. This sets *START to point to a view of the start of
2370 // the file. It sets *READ_SIZE to the number of bytes in the view.
2373 is_elf_object(Input_file
* input_file
, off_t offset
,
2374 const unsigned char** start
, int *read_size
);
2376 // Return an Object appropriate for the input file. P is BYTES long,
2377 // and holds the ELF header. If PUNCONFIGURED is not NULL, then if
2378 // this sees an object the linker is not configured to support, it
2379 // sets *PUNCONFIGURED to true and returns NULL without giving an
2383 make_elf_object(const std::string
& name
, Input_file
*,
2384 off_t offset
, const unsigned char* p
,
2385 section_offset_type bytes
, bool* punconfigured
);
2387 } // end namespace gold
2389 #endif // !defined(GOLD_OBJECT_H)