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
;
45 class Output_symtab_xindex
;
48 class Object_merge_map
;
49 class Relocatable_relocs
;
52 template<typename Stringpool_char
>
53 class Stringpool_template
;
55 // Data to pass from read_symbols() to add_symbols().
57 struct Read_symbols_data
60 : section_headers(NULL
), section_names(NULL
), symbols(NULL
),
61 symbol_names(NULL
), versym(NULL
), verdef(NULL
), verneed(NULL
)
67 File_view
* section_headers
;
69 File_view
* section_names
;
70 // Size of section name data in bytes.
71 section_size_type section_names_size
;
74 // Size of symbol data in bytes.
75 section_size_type symbols_size
;
76 // Offset of external symbols within symbol data. This structure
77 // sometimes contains only external symbols, in which case this will
78 // be zero. Sometimes it contains all symbols.
79 section_offset_type external_symbols_offset
;
81 File_view
* symbol_names
;
82 // Size of symbol name data in bytes.
83 section_size_type symbol_names_size
;
85 // Version information. This is only used on dynamic objects.
86 // Version symbol data (from SHT_GNU_versym section).
88 section_size_type versym_size
;
89 // Version definition data (from SHT_GNU_verdef section).
91 section_size_type verdef_size
;
92 unsigned int verdef_info
;
93 // Needed version data (from SHT_GNU_verneed section).
95 section_size_type verneed_size
;
96 unsigned int verneed_info
;
99 // Information used to print error messages.
101 struct Symbol_location_info
103 std::string source_file
;
104 std::string enclosing_symbol_name
;
108 // Data about a single relocation section. This is read in
109 // read_relocs and processed in scan_relocs.
111 struct Section_relocs
118 { delete this->contents
; }
120 // Index of reloc section.
121 unsigned int reloc_shndx
;
122 // Index of section that relocs apply to.
123 unsigned int data_shndx
;
124 // Contents of reloc section.
126 // Reloc section type.
127 unsigned int sh_type
;
128 // Number of reloc entries.
131 Output_section
* output_section
;
132 // Whether this section has special handling for offsets.
133 bool needs_special_offset_handling
;
134 // Whether the data section is allocated (has the SHF_ALLOC flag set).
135 bool is_data_section_allocated
;
138 // Relocations in an object file. This is read in read_relocs and
139 // processed in scan_relocs.
141 struct Read_relocs_data
144 : local_symbols(NULL
)
148 { delete this->local_symbols
; }
150 typedef std::vector
<Section_relocs
> Relocs_list
;
153 // The local symbols.
154 File_view
* local_symbols
;
157 // The Xindex class manages section indexes for objects with more than
163 Xindex(int large_shndx_offset
)
164 : large_shndx_offset_(large_shndx_offset
), symtab_xindex_()
167 // Initialize the symtab_xindex_ array, given the object and the
168 // section index of the symbol table to use.
169 template<int size
, bool big_endian
>
171 initialize_symtab_xindex(Object
*, unsigned int symtab_shndx
);
173 // Read in the symtab_xindex_ array, given its section index.
174 // PSHDRS may optionally point to the section headers.
175 template<int size
, bool big_endian
>
177 read_symtab_xindex(Object
*, unsigned int xindex_shndx
,
178 const unsigned char* pshdrs
);
180 // Symbol SYMNDX in OBJECT has a section of SHN_XINDEX; return the
181 // real section index.
183 sym_xindex_to_shndx(Object
* object
, unsigned int symndx
);
186 // The type of the array giving the real section index for symbols
187 // whose st_shndx field holds SHN_XINDEX.
188 typedef std::vector
<unsigned int> Symtab_xindex
;
190 // Adjust a section index if necessary. This should only be called
191 // for ordinary section indexes.
193 adjust_shndx(unsigned int shndx
)
195 if (shndx
>= elfcpp::SHN_LORESERVE
)
196 shndx
+= this->large_shndx_offset_
;
200 // Adjust to apply to large section indexes.
201 int large_shndx_offset_
;
202 // The data from the SHT_SYMTAB_SHNDX section.
203 Symtab_xindex symtab_xindex_
;
206 // Object is an abstract base class which represents either a 32-bit
207 // or a 64-bit input object. This can be a regular object file
208 // (ET_REL) or a shared object (ET_DYN).
213 typedef std::vector
<Symbol
*> Symbols
;
215 // NAME is the name of the object as we would report it to the user
216 // (e.g., libfoo.a(bar.o) if this is in an archive. INPUT_FILE is
217 // used to read the file. OFFSET is the offset within the input
218 // file--0 for a .o or .so file, something else for a .a file.
219 Object(const std::string
& name
, Input_file
* input_file
, bool is_dynamic
,
221 : name_(name
), input_file_(input_file
), offset_(offset
), shnum_(-1U),
222 is_dynamic_(is_dynamic
), is_needed_(false), uses_split_stack_(false),
223 has_no_split_stack_(false), no_export_(false), xindex_(NULL
)
224 { input_file
->file().add_object(); }
227 { this->input_file_
->file().remove_object(); }
229 // Return the name of the object as we would report it to the tuser.
232 { return this->name_
; }
234 // Get the offset into the file.
237 { return this->offset_
; }
239 // Return whether this is a dynamic object.
242 { return this->is_dynamic_
; }
244 // Return whether this object is needed--true if it is a dynamic
245 // object which defines some symbol referenced by a regular object.
246 // We keep the flag here rather than in Dynobj for convenience when
250 { return this->is_needed_
; }
252 // Record that this object is needed.
255 { this->is_needed_
= true; }
257 // Return whether this object was compiled with -fsplit-stack.
259 uses_split_stack() const
260 { return this->uses_split_stack_
; }
262 // Return whether this object contains any functions compiled with
263 // the no_split_stack attribute.
265 has_no_split_stack() const
266 { return this->has_no_split_stack_
; }
268 // Returns NULL for Objects that are not plugin objects. This method
269 // is overridden in the Pluginobj class.
272 { return this->do_pluginobj(); }
274 // Get the file. We pass on const-ness.
277 { return this->input_file_
; }
281 { return this->input_file_
; }
283 // Lock the underlying file.
286 { this->input_file()->file().lock(t
); }
288 // Unlock the underlying file.
290 unlock(const Task
* t
)
291 { this->input_file()->file().unlock(t
); }
293 // Return whether the underlying file is locked.
296 { return this->input_file()->file().is_locked(); }
298 // Return the token, so that the task can be queued.
301 { return this->input_file()->file().token(); }
303 // Release the underlying file.
306 { this->input_file_
->file().release(); }
308 // Return whether we should just read symbols from this file.
311 { return this->input_file()->just_symbols(); }
313 // Get the number of sections.
316 { return this->shnum_
; }
318 // Return a view of the contents of a section. Set *PLEN to the
319 // size. CACHE is a hint as in File_read::get_view.
321 section_contents(unsigned int shndx
, section_size_type
* plen
, bool cache
);
323 // Adjust a symbol's section index as needed. SYMNDX is the index
324 // of the symbol and SHNDX is the symbol's section from
325 // get_st_shndx. This returns the section index. It sets
326 // *IS_ORDINARY to indicate whether this is a normal section index,
327 // rather than a special code between SHN_LORESERVE and
330 adjust_sym_shndx(unsigned int symndx
, unsigned int shndx
, bool* is_ordinary
)
332 if (shndx
< elfcpp::SHN_LORESERVE
)
334 else if (shndx
== elfcpp::SHN_XINDEX
)
336 if (this->xindex_
== NULL
)
337 this->xindex_
= this->do_initialize_xindex();
338 shndx
= this->xindex_
->sym_xindex_to_shndx(this, symndx
);
342 *is_ordinary
= false;
346 // Return the size of a section given a section index.
348 section_size(unsigned int shndx
)
349 { return this->do_section_size(shndx
); }
351 // Return the name of a section given a section index.
353 section_name(unsigned int shndx
)
354 { return this->do_section_name(shndx
); }
356 // Return the section flags given a section index.
358 section_flags(unsigned int shndx
)
359 { return this->do_section_flags(shndx
); }
361 // Return the section entsize given a section index.
363 section_entsize(unsigned int shndx
)
364 { return this->do_section_entsize(shndx
); }
366 // Return the section address given a section index.
368 section_address(unsigned int shndx
)
369 { return this->do_section_address(shndx
); }
371 // Return the section type given a section index.
373 section_type(unsigned int shndx
)
374 { return this->do_section_type(shndx
); }
376 // Return the section link field given a section index.
378 section_link(unsigned int shndx
)
379 { return this->do_section_link(shndx
); }
381 // Return the section info field given a section index.
383 section_info(unsigned int shndx
)
384 { return this->do_section_info(shndx
); }
386 // Return the required section alignment given a section index.
388 section_addralign(unsigned int shndx
)
389 { return this->do_section_addralign(shndx
); }
391 // Return the output section given a section index.
393 output_section(unsigned int shndx
) const
394 { return this->do_output_section(shndx
); }
396 // Given a section index, return the offset in the Output_section.
397 // The return value will be -1U if the section is specially mapped,
398 // such as a merge section.
400 output_section_offset(unsigned int shndx
) const
401 { return this->do_output_section_offset(shndx
); }
403 // Read the symbol information.
405 read_symbols(Read_symbols_data
* sd
)
406 { return this->do_read_symbols(sd
); }
408 // Pass sections which should be included in the link to the Layout
409 // object, and record where the sections go in the output file.
411 layout(Symbol_table
* symtab
, Layout
* layout
, Read_symbols_data
* sd
)
412 { this->do_layout(symtab
, layout
, sd
); }
414 // Add symbol information to the global symbol table.
416 add_symbols(Symbol_table
* symtab
, Read_symbols_data
* sd
, Layout
*layout
)
417 { this->do_add_symbols(symtab
, sd
, layout
); }
419 // Add symbol information to the global symbol table.
420 Archive::Should_include
421 should_include_member(Symbol_table
* symtab
, Layout
* layout
,
422 Read_symbols_data
* sd
, std::string
* why
)
423 { return this->do_should_include_member(symtab
, layout
, sd
, why
); }
425 // Functions and types for the elfcpp::Elf_file interface. This
426 // permit us to use Object as the File template parameter for
429 // The View class is returned by view. It must support a single
430 // method, data(). This is trivial, because get_view does what we
435 View(const unsigned char* p
)
444 const unsigned char* p_
;
449 view(off_t file_offset
, section_size_type data_size
)
450 { return View(this->get_view(file_offset
, data_size
, true, true)); }
454 error(const char* format
, ...) const ATTRIBUTE_PRINTF_2
;
456 // A location in the file.
462 Location(off_t fo
, section_size_type ds
)
463 : file_offset(fo
), data_size(ds
)
467 // Get a View given a Location.
468 View
view(Location loc
)
469 { return View(this->get_view(loc
.file_offset
, loc
.data_size
, true, true)); }
471 // Get a view into the underlying file.
473 get_view(off_t start
, section_size_type size
, bool aligned
, bool cache
)
475 return this->input_file()->file().get_view(this->offset_
, start
, size
,
479 // Get a lasting view into the underlying file.
481 get_lasting_view(off_t start
, section_size_type size
, bool aligned
,
484 return this->input_file()->file().get_lasting_view(this->offset_
, start
,
485 size
, aligned
, cache
);
488 // Read data from the underlying file.
490 read(off_t start
, section_size_type size
, void* p
)
491 { this->input_file()->file().read(start
+ this->offset_
, size
, p
); }
493 // Read multiple data from the underlying file.
495 read_multiple(const File_read::Read_multiple
& rm
)
496 { this->input_file()->file().read_multiple(this->offset_
, rm
); }
498 // Stop caching views in the underlying file.
500 clear_view_cache_marks()
501 { this->input_file()->file().clear_view_cache_marks(); }
503 // Get the number of global symbols defined by this object, and the
504 // number of the symbols whose final definition came from this
507 get_global_symbol_counts(const Symbol_table
* symtab
, size_t* defined
,
509 { this->do_get_global_symbol_counts(symtab
, defined
, used
); }
511 // Get the symbols defined in this object.
513 get_global_symbols() const
514 { return this->do_get_global_symbols(); }
516 // Return whether this object was found in a system directory.
518 is_in_system_directory() const
519 { return this->input_file()->is_in_system_directory(); }
521 // Return whether we found this object by searching a directory.
524 { return this->input_file()->will_search_for(); }
528 { return this->no_export_
; }
531 set_no_export(bool value
)
532 { this->no_export_
= value
; }
534 // Return TRUE if the section is a compressed debug section, and set
535 // *UNCOMPRESSED_SIZE to the size of the uncompressed data.
537 section_is_compressed(unsigned int shndx
,
538 section_size_type
* uncompressed_size
) const
539 { return this->do_section_is_compressed(shndx
, uncompressed_size
); }
541 // Return the index of the first incremental relocation for symbol SYMNDX.
543 get_incremental_reloc_base(unsigned int symndx
) const
544 { return this->do_get_incremental_reloc_base(symndx
); }
546 // Return the number of incremental relocations for symbol SYMNDX.
548 get_incremental_reloc_count(unsigned int symndx
) const
549 { return this->do_get_incremental_reloc_count(symndx
); }
552 // Returns NULL for Objects that are not plugin objects. This method
553 // is overridden in the Pluginobj class.
558 // Read the symbols--implemented by child class.
560 do_read_symbols(Read_symbols_data
*) = 0;
562 // Lay out sections--implemented by child class.
564 do_layout(Symbol_table
*, Layout
*, Read_symbols_data
*) = 0;
566 // Add symbol information to the global symbol table--implemented by
569 do_add_symbols(Symbol_table
*, Read_symbols_data
*, Layout
*) = 0;
571 virtual Archive::Should_include
572 do_should_include_member(Symbol_table
* symtab
, Layout
*, Read_symbols_data
*,
573 std::string
* why
) = 0;
575 // Return the location of the contents of a section. Implemented by
578 do_section_contents(unsigned int shndx
) = 0;
580 // Get the size of a section--implemented by child class.
582 do_section_size(unsigned int shndx
) = 0;
584 // Get the name of a section--implemented by child class.
586 do_section_name(unsigned int shndx
) = 0;
588 // Get section flags--implemented by child class.
590 do_section_flags(unsigned int shndx
) = 0;
592 // Get section entsize--implemented by child class.
594 do_section_entsize(unsigned int shndx
) = 0;
596 // Get section address--implemented by child class.
598 do_section_address(unsigned int shndx
) = 0;
600 // Get section type--implemented by child class.
602 do_section_type(unsigned int shndx
) = 0;
604 // Get section link field--implemented by child class.
606 do_section_link(unsigned int shndx
) = 0;
608 // Get section info field--implemented by child class.
610 do_section_info(unsigned int shndx
) = 0;
612 // Get section alignment--implemented by child class.
614 do_section_addralign(unsigned int shndx
) = 0;
616 // Return the output section given a section index--implemented
618 virtual Output_section
*
619 do_output_section(unsigned int) const
620 { gold_unreachable(); }
622 // Get the offset of a section--implemented by child class.
624 do_output_section_offset(unsigned int) const
625 { gold_unreachable(); }
627 // Return the Xindex structure to use.
629 do_initialize_xindex() = 0;
631 // Implement get_global_symbol_counts--implemented by child class.
633 do_get_global_symbol_counts(const Symbol_table
*, size_t*, size_t*) const = 0;
635 virtual const Symbols
*
636 do_get_global_symbols() const = 0;
638 // Set the number of sections.
641 { this->shnum_
= shnum
; }
643 // Functions used by both Sized_relobj and Sized_dynobj.
645 // Read the section data into a Read_symbols_data object.
646 template<int size
, bool big_endian
>
648 read_section_data(elfcpp::Elf_file
<size
, big_endian
, Object
>*,
651 // Let the child class initialize the xindex object directly.
653 set_xindex(Xindex
* xindex
)
655 gold_assert(this->xindex_
== NULL
);
656 this->xindex_
= xindex
;
659 // If NAME is the name of a special .gnu.warning section, arrange
660 // for the warning to be issued. SHNDX is the section index.
661 // Return whether it is a warning section.
663 handle_gnu_warning_section(const char* name
, unsigned int shndx
,
666 // If NAME is the name of the special section which indicates that
667 // this object was compiled with -fstack-split, mark it accordingly,
668 // and return true. Otherwise return false.
670 handle_split_stack_section(const char* name
);
672 // Return TRUE if the section is a compressed debug section, and set
673 // *UNCOMPRESSED_SIZE to the size of the uncompressed data.
675 do_section_is_compressed(unsigned int, section_size_type
*) const
678 // Return the index of the first incremental relocation for symbol SYMNDX--
679 // implemented by child class.
681 do_get_incremental_reloc_base(unsigned int) const
682 { gold_unreachable(); }
684 // Return the number of incremental relocations for symbol SYMNDX--
685 // implemented by child class.
687 do_get_incremental_reloc_count(unsigned int) const
688 { gold_unreachable(); }
691 // This class may not be copied.
692 Object(const Object
&);
693 Object
& operator=(const Object
&);
695 // Name of object as printed to user.
697 // For reading the file.
698 Input_file
* input_file_
;
699 // Offset within the file--0 for an object file, non-0 for an
702 // Number of input sections.
704 // Whether this is a dynamic object.
705 bool is_dynamic_
: 1;
706 // Whether this object is needed. This is only set for dynamic
707 // objects, and means that the object defined a symbol which was
708 // used by a reference from a regular object.
710 // Whether this object was compiled with -fsplit-stack.
711 bool uses_split_stack_
: 1;
712 // Whether this object contains any functions compiled with the
713 // no_split_stack attribute.
714 bool has_no_split_stack_
: 1;
715 // True if exclude this object from automatic symbol export.
716 // This is used only for archive objects.
718 // Many sections for objects with more than SHN_LORESERVE sections.
722 // A regular object (ET_REL). This is an abstract base class itself.
723 // The implementation is the template class Sized_relobj.
725 class Relobj
: public Object
728 Relobj(const std::string
& name
, Input_file
* input_file
, off_t offset
= 0)
729 : Object(name
, input_file
, false, offset
),
731 map_to_relocatable_relocs_(NULL
),
732 object_merge_map_(NULL
),
733 relocs_must_follow_section_writes_(false),
739 // During garbage collection, the Read_symbols_data pass for
740 // each object is stored as layout needs to be done after
744 { return this->sd_
; }
746 // Decides which section names have to be included in the worklist
749 is_section_name_included(const char *name
);
752 copy_symbols_data(Symbols_data
* gc_sd
, Read_symbols_data
* sd
,
753 unsigned int section_header_size
);
756 set_symbols_data(Symbols_data
* sd
)
759 // During garbage collection, the Read_relocs pass for all objects
760 // is done before scanning the relocs. In that case, this->rd_ is
761 // used to store the information from Read_relocs for each object.
762 // This data is also used to compute the list of relevant sections.
765 { return this->rd_
; }
768 set_relocs_data(Read_relocs_data
* rd
)
772 is_output_section_offset_invalid(unsigned int shndx
) const = 0;
776 read_relocs(Read_relocs_data
* rd
)
777 { return this->do_read_relocs(rd
); }
779 // Process the relocs, during garbage collection only.
781 gc_process_relocs(Symbol_table
* symtab
, Layout
* layout
, Read_relocs_data
* rd
)
782 { return this->do_gc_process_relocs(symtab
, layout
, rd
); }
784 // Scan the relocs and adjust the symbol table.
786 scan_relocs(Symbol_table
* symtab
, Layout
* layout
, Read_relocs_data
* rd
)
787 { return this->do_scan_relocs(symtab
, layout
, rd
); }
789 // The number of local symbols in the input symbol table.
791 local_symbol_count() const
792 { return this->do_local_symbol_count(); }
794 // Initial local symbol processing: count the number of local symbols
795 // in the output symbol table and dynamic symbol table; add local symbol
796 // names to *POOL and *DYNPOOL.
798 count_local_symbols(Stringpool_template
<char>* pool
,
799 Stringpool_template
<char>* dynpool
)
800 { return this->do_count_local_symbols(pool
, dynpool
); }
802 // Set the values of the local symbols, set the output symbol table
803 // indexes for the local variables, and set the offset where local
804 // symbol information will be stored. Returns the new local symbol index.
806 finalize_local_symbols(unsigned int index
, off_t off
, Symbol_table
* symtab
)
807 { return this->do_finalize_local_symbols(index
, off
, symtab
); }
809 // Set the output dynamic symbol table indexes for the local variables.
811 set_local_dynsym_indexes(unsigned int index
)
812 { return this->do_set_local_dynsym_indexes(index
); }
814 // Set the offset where local dynamic symbol information will be stored.
816 set_local_dynsym_offset(off_t off
)
817 { return this->do_set_local_dynsym_offset(off
); }
819 // Relocate the input sections and write out the local symbols.
821 relocate(const Symbol_table
* symtab
, const Layout
* layout
, Output_file
* of
)
822 { return this->do_relocate(symtab
, layout
, of
); }
824 // Return whether an input section is being included in the link.
826 is_section_included(unsigned int shndx
) const
828 gold_assert(shndx
< this->output_sections_
.size());
829 return this->output_sections_
[shndx
] != NULL
;
832 // The the output section of the input section with index SHNDX.
833 // This is only used currently to remove a section from the link in
836 set_output_section(unsigned int shndx
, Output_section
* os
)
838 gold_assert(shndx
< this->output_sections_
.size());
839 this->output_sections_
[shndx
] = os
;
842 // Set the offset of an input section within its output section.
844 set_section_offset(unsigned int shndx
, uint64_t off
)
845 { this->do_set_section_offset(shndx
, off
); }
847 // Return true if we need to wait for output sections to be written
848 // before we can apply relocations. This is true if the object has
849 // any relocations for sections which require special handling, such
850 // as the exception frame section.
852 relocs_must_follow_section_writes() const
853 { return this->relocs_must_follow_section_writes_
; }
855 // Return the object merge map.
858 { return this->object_merge_map_
; }
860 // Set the object merge map.
862 set_merge_map(Object_merge_map
* object_merge_map
)
864 gold_assert(this->object_merge_map_
== NULL
);
865 this->object_merge_map_
= object_merge_map
;
868 // Record the relocatable reloc info for an input reloc section.
870 set_relocatable_relocs(unsigned int reloc_shndx
, Relocatable_relocs
* rr
)
872 gold_assert(reloc_shndx
< this->shnum());
873 (*this->map_to_relocatable_relocs_
)[reloc_shndx
] = rr
;
876 // Get the relocatable reloc info for an input reloc section.
878 relocatable_relocs(unsigned int reloc_shndx
)
880 gold_assert(reloc_shndx
< this->shnum());
881 return (*this->map_to_relocatable_relocs_
)[reloc_shndx
];
884 // Layout sections whose layout was deferred while waiting for
885 // input files from a plugin.
887 layout_deferred_sections(Layout
* layout
)
888 { this->do_layout_deferred_sections(layout
); }
890 // Return the index of the first incremental relocation for symbol SYMNDX.
892 do_get_incremental_reloc_base(unsigned int symndx
) const
893 { return this->reloc_bases_
[symndx
]; }
895 // Return the number of incremental relocations for symbol SYMNDX.
897 do_get_incremental_reloc_count(unsigned int symndx
) const
898 { return this->reloc_counts_
[symndx
]; }
901 // The output section to be used for each input section, indexed by
902 // the input section number. The output section is NULL if the
903 // input section is to be discarded.
904 typedef std::vector
<Output_section
*> Output_sections
;
906 // Read the relocs--implemented by child class.
908 do_read_relocs(Read_relocs_data
*) = 0;
910 // Process the relocs--implemented by child class.
912 do_gc_process_relocs(Symbol_table
*, Layout
*, Read_relocs_data
*) = 0;
914 // Scan the relocs--implemented by child class.
916 do_scan_relocs(Symbol_table
*, Layout
*, Read_relocs_data
*) = 0;
918 // Return the number of local symbols--implemented by child class.
920 do_local_symbol_count() const = 0;
922 // Count local symbols--implemented by child class.
924 do_count_local_symbols(Stringpool_template
<char>*,
925 Stringpool_template
<char>*) = 0;
927 // Finalize the local symbols. Set the output symbol table indexes
928 // for the local variables, and set the offset where local symbol
929 // information will be stored.
931 do_finalize_local_symbols(unsigned int, off_t
, Symbol_table
*) = 0;
933 // Set the output dynamic symbol table indexes for the local variables.
935 do_set_local_dynsym_indexes(unsigned int) = 0;
937 // Set the offset where local dynamic symbol information will be stored.
939 do_set_local_dynsym_offset(off_t
) = 0;
941 // Relocate the input sections and write out the local
942 // symbols--implemented by child class.
944 do_relocate(const Symbol_table
* symtab
, const Layout
*, Output_file
* of
) = 0;
946 // Set the offset of a section--implemented by child class.
948 do_set_section_offset(unsigned int shndx
, uint64_t off
) = 0;
950 // Layout sections whose layout was deferred while waiting for
951 // input files from a plugin--implemented by child class.
953 do_layout_deferred_sections(Layout
*) = 0;
955 // Given a section index, return the corresponding Output_section.
956 // The return value will be NULL if the section is not included in
959 do_output_section(unsigned int shndx
) const
961 gold_assert(shndx
< this->output_sections_
.size());
962 return this->output_sections_
[shndx
];
965 // Return the vector mapping input sections to output sections.
968 { return this->output_sections_
; }
970 const Output_sections
&
971 output_sections() const
972 { return this->output_sections_
; }
974 // Set the size of the relocatable relocs array.
976 size_relocatable_relocs()
978 this->map_to_relocatable_relocs_
=
979 new std::vector
<Relocatable_relocs
*>(this->shnum());
982 // Record that we must wait for the output sections to be written
983 // before applying relocations.
985 set_relocs_must_follow_section_writes()
986 { this->relocs_must_follow_section_writes_
= true; }
988 // Allocate the array for counting incremental relocations.
990 allocate_incremental_reloc_counts()
992 unsigned int nsyms
= this->do_get_global_symbols()->size();
993 this->reloc_counts_
= new unsigned int[nsyms
];
994 gold_assert(this->reloc_counts_
!= NULL
);
995 memset(this->reloc_counts_
, 0, nsyms
* sizeof(unsigned int));
998 // Record a relocation in this object referencing global symbol SYMNDX.
999 // Used for tracking incremental link information.
1001 count_incremental_reloc(unsigned int symndx
)
1003 unsigned int nsyms
= this->do_get_global_symbols()->size();
1004 gold_assert(symndx
< nsyms
);
1005 gold_assert(this->reloc_counts_
!= NULL
);
1006 ++this->reloc_counts_
[symndx
];
1009 // Finalize the incremental relocation information.
1011 finalize_incremental_relocs(Layout
* layout
);
1013 // Return the index of the next relocation to be written for global symbol
1014 // SYMNDX. Only valid after finalize_incremental_relocs() has been called.
1016 next_incremental_reloc_index(unsigned int symndx
)
1018 unsigned int nsyms
= this->do_get_global_symbols()->size();
1020 gold_assert(this->reloc_counts_
!= NULL
);
1021 gold_assert(this->reloc_bases_
!= NULL
);
1022 gold_assert(symndx
< nsyms
);
1024 unsigned int counter
= this->reloc_counts_
[symndx
]++;
1025 return this->reloc_bases_
[symndx
] + counter
;
1029 // Mapping from input sections to output section.
1030 Output_sections output_sections_
;
1031 // Mapping from input section index to the information recorded for
1032 // the relocations. This is only used for a relocatable link.
1033 std::vector
<Relocatable_relocs
*>* map_to_relocatable_relocs_
;
1034 // Mappings for merge sections. This is managed by the code in the
1036 Object_merge_map
* object_merge_map_
;
1037 // Whether we need to wait for output sections to be written before
1038 // we can apply relocations.
1039 bool relocs_must_follow_section_writes_
;
1040 // Used to store the relocs data computed by the Read_relocs pass.
1041 // Used during garbage collection of unused sections.
1042 Read_relocs_data
* rd_
;
1043 // Used to store the symbols data computed by the Read_symbols pass.
1044 // Again used during garbage collection when laying out referenced
1046 gold::Symbols_data
*sd_
;
1047 // Per-symbol counts of relocations, for incremental links.
1048 unsigned int* reloc_counts_
;
1049 // Per-symbol base indexes of relocations, for incremental links.
1050 unsigned int* reloc_bases_
;
1053 // This class is used to handle relocations against a section symbol
1054 // in an SHF_MERGE section. For such a symbol, we need to know the
1055 // addend of the relocation before we can determine the final value.
1056 // The addend gives us the location in the input section, and we can
1057 // determine how it is mapped to the output section. For a
1058 // non-section symbol, we apply the addend to the final value of the
1059 // symbol; that is done in finalize_local_symbols, and does not use
1063 class Merged_symbol_value
1066 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Value
;
1068 // We use a hash table to map offsets in the input section to output
1070 typedef Unordered_map
<section_offset_type
, Value
> Output_addresses
;
1072 Merged_symbol_value(Value input_value
, Value output_start_address
)
1073 : input_value_(input_value
), output_start_address_(output_start_address
),
1077 // Initialize the hash table.
1079 initialize_input_to_output_map(const Relobj
*, unsigned int input_shndx
);
1081 // Release the hash table to save space.
1083 free_input_to_output_map()
1084 { this->output_addresses_
.clear(); }
1086 // Get the output value corresponding to an addend. The object and
1087 // input section index are passed in because the caller will have
1088 // them; otherwise we could store them here.
1090 value(const Relobj
* object
, unsigned int input_shndx
, Value addend
) const
1092 // This is a relocation against a section symbol. ADDEND is the
1093 // offset in the section. The result should be the start of some
1094 // merge area. If the object file wants something else, it should
1095 // use a regular symbol rather than a section symbol.
1096 // Unfortunately, PR 6658 shows a case in which the object file
1097 // refers to the section symbol, but uses a negative ADDEND to
1098 // compensate for a PC relative reloc. We can't handle the
1099 // general case. However, we can handle the special case of a
1100 // negative addend, by assuming that it refers to the start of the
1101 // section. Of course, that means that we have to guess when
1102 // ADDEND is negative. It is normal to see a 32-bit value here
1103 // even when the template parameter size is 64, as 64-bit object
1104 // file formats have 32-bit relocations. We know this is a merge
1105 // section, so we know it has to fit into memory. So we assume
1106 // that we won't see a value larger than a large 32-bit unsigned
1107 // value. This will break objects with very very large merge
1108 // sections; they probably break in other ways anyhow.
1109 Value input_offset
= this->input_value_
;
1110 if (addend
< 0xffffff00)
1112 input_offset
+= addend
;
1115 typename
Output_addresses::const_iterator p
=
1116 this->output_addresses_
.find(input_offset
);
1117 if (p
!= this->output_addresses_
.end())
1118 return p
->second
+ addend
;
1120 return (this->value_from_output_section(object
, input_shndx
, input_offset
)
1125 // Get the output value for an input offset if we couldn't find it
1126 // in the hash table.
1128 value_from_output_section(const Relobj
*, unsigned int input_shndx
,
1129 Value input_offset
) const;
1131 // The value of the section symbol in the input file. This is
1132 // normally zero, but could in principle be something else.
1134 // The start address of this merged section in the output file.
1135 Value output_start_address_
;
1136 // A hash table which maps offsets in the input section to output
1137 // addresses. This only maps specific offsets, not all offsets.
1138 Output_addresses output_addresses_
;
1141 // This POD class is holds the value of a symbol. This is used for
1142 // local symbols, and for all symbols during relocation processing.
1143 // For special sections, such as SHF_MERGE sections, this calls a
1144 // function to get the final symbol value.
1150 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Value
;
1153 : output_symtab_index_(0), output_dynsym_index_(-1U), input_shndx_(0),
1154 is_ordinary_shndx_(false), is_section_symbol_(false),
1155 is_tls_symbol_(false), is_ifunc_symbol_(false), has_output_value_(true)
1156 { this->u_
.value
= 0; }
1158 // Get the value of this symbol. OBJECT is the object in which this
1159 // symbol is defined, and ADDEND is an addend to add to the value.
1160 template<bool big_endian
>
1162 value(const Sized_relobj
<size
, big_endian
>* object
, Value addend
) const
1164 if (this->has_output_value_
)
1165 return this->u_
.value
+ addend
;
1168 gold_assert(this->is_ordinary_shndx_
);
1169 return this->u_
.merged_symbol_value
->value(object
, this->input_shndx_
,
1174 // Set the value of this symbol in the output symbol table.
1176 set_output_value(Value value
)
1177 { this->u_
.value
= value
; }
1179 // For a section symbol in a merged section, we need more
1182 set_merged_symbol_value(Merged_symbol_value
<size
>* msv
)
1184 gold_assert(this->is_section_symbol_
);
1185 this->has_output_value_
= false;
1186 this->u_
.merged_symbol_value
= msv
;
1189 // Initialize the input to output map for a section symbol in a
1190 // merged section. We also initialize the value of a non-section
1191 // symbol in a merged section.
1193 initialize_input_to_output_map(const Relobj
* object
)
1195 if (!this->has_output_value_
)
1197 gold_assert(this->is_section_symbol_
&& this->is_ordinary_shndx_
);
1198 Merged_symbol_value
<size
>* msv
= this->u_
.merged_symbol_value
;
1199 msv
->initialize_input_to_output_map(object
, this->input_shndx_
);
1203 // Free the input to output map for a section symbol in a merged
1206 free_input_to_output_map()
1208 if (!this->has_output_value_
)
1209 this->u_
.merged_symbol_value
->free_input_to_output_map();
1212 // Set the value of the symbol from the input file. This is only
1213 // called by count_local_symbols, to communicate the value to
1214 // finalize_local_symbols.
1216 set_input_value(Value value
)
1217 { this->u_
.value
= value
; }
1219 // Return the input value. This is only called by
1220 // finalize_local_symbols and (in special cases) relocate_section.
1223 { return this->u_
.value
; }
1225 // Return whether we have set the index in the output symbol table
1228 is_output_symtab_index_set() const
1230 return (this->output_symtab_index_
!= 0
1231 && this->output_symtab_index_
!= -2U);
1234 // Return whether this symbol may be discarded from the normal
1237 may_be_discarded_from_output_symtab() const
1239 gold_assert(!this->is_output_symtab_index_set());
1240 return this->output_symtab_index_
!= -2U;
1243 // Return whether this symbol has an entry in the output symbol
1246 has_output_symtab_entry() const
1248 gold_assert(this->is_output_symtab_index_set());
1249 return this->output_symtab_index_
!= -1U;
1252 // Return the index in the output symbol table.
1254 output_symtab_index() const
1256 gold_assert(this->is_output_symtab_index_set()
1257 && this->output_symtab_index_
!= -1U);
1258 return this->output_symtab_index_
;
1261 // Set the index in the output symbol table.
1263 set_output_symtab_index(unsigned int i
)
1265 gold_assert(!this->is_output_symtab_index_set());
1266 gold_assert(i
!= 0 && i
!= -1U && i
!= -2U);
1267 this->output_symtab_index_
= i
;
1270 // Record that this symbol should not go into the output symbol
1273 set_no_output_symtab_entry()
1275 gold_assert(this->output_symtab_index_
== 0);
1276 this->output_symtab_index_
= -1U;
1279 // Record that this symbol must go into the output symbol table,
1280 // because it there is a relocation that uses it.
1282 set_must_have_output_symtab_entry()
1284 gold_assert(!this->is_output_symtab_index_set());
1285 this->output_symtab_index_
= -2U;
1288 // Set the index in the output dynamic symbol table.
1290 set_needs_output_dynsym_entry()
1292 gold_assert(!this->is_section_symbol());
1293 this->output_dynsym_index_
= 0;
1296 // Return whether this symbol should go into the dynamic symbol
1299 needs_output_dynsym_entry() const
1301 return this->output_dynsym_index_
!= -1U;
1304 // Return whether this symbol has an entry in the dynamic symbol
1307 has_output_dynsym_entry() const
1309 gold_assert(this->output_dynsym_index_
!= 0);
1310 return this->output_dynsym_index_
!= -1U;
1313 // Record that this symbol should go into the dynamic symbol table.
1315 set_output_dynsym_index(unsigned int i
)
1317 gold_assert(this->output_dynsym_index_
== 0);
1318 gold_assert(i
!= 0 && i
!= -1U);
1319 this->output_dynsym_index_
= i
;
1322 // Return the index in the output dynamic symbol table.
1324 output_dynsym_index() const
1326 gold_assert(this->output_dynsym_index_
!= 0
1327 && this->output_dynsym_index_
!= -1U);
1328 return this->output_dynsym_index_
;
1331 // Set the index of the input section in the input file.
1333 set_input_shndx(unsigned int i
, bool is_ordinary
)
1335 this->input_shndx_
= i
;
1336 // input_shndx_ field is a bitfield, so make sure that the value
1338 gold_assert(this->input_shndx_
== i
);
1339 this->is_ordinary_shndx_
= is_ordinary
;
1342 // Return the index of the input section in the input file.
1344 input_shndx(bool* is_ordinary
) const
1346 *is_ordinary
= this->is_ordinary_shndx_
;
1347 return this->input_shndx_
;
1350 // Whether this is a section symbol.
1352 is_section_symbol() const
1353 { return this->is_section_symbol_
; }
1355 // Record that this is a section symbol.
1357 set_is_section_symbol()
1359 gold_assert(!this->needs_output_dynsym_entry());
1360 this->is_section_symbol_
= true;
1363 // Record that this is a TLS symbol.
1366 { this->is_tls_symbol_
= true; }
1368 // Return true if this is a TLS symbol.
1370 is_tls_symbol() const
1371 { return this->is_tls_symbol_
; }
1373 // Record that this is an IFUNC symbol.
1375 set_is_ifunc_symbol()
1376 { this->is_ifunc_symbol_
= true; }
1378 // Return true if this is an IFUNC symbol.
1380 is_ifunc_symbol() const
1381 { return this->is_ifunc_symbol_
; }
1384 // The index of this local symbol in the output symbol table. This
1385 // will be 0 if no value has been assigned yet, and the symbol may
1386 // be omitted. This will be -1U if the symbol should not go into
1387 // the symbol table. This will be -2U if the symbol must go into
1388 // the symbol table, but no index has been assigned yet.
1389 unsigned int output_symtab_index_
;
1390 // The index of this local symbol in the dynamic symbol table. This
1391 // will be -1U if the symbol should not go into the symbol table.
1392 unsigned int output_dynsym_index_
;
1393 // The section index in the input file in which this symbol is
1395 unsigned int input_shndx_
: 27;
1396 // Whether the section index is an ordinary index, not a special
1398 bool is_ordinary_shndx_
: 1;
1399 // Whether this is a STT_SECTION symbol.
1400 bool is_section_symbol_
: 1;
1401 // Whether this is a STT_TLS symbol.
1402 bool is_tls_symbol_
: 1;
1403 // Whether this is a STT_GNU_IFUNC symbol.
1404 bool is_ifunc_symbol_
: 1;
1405 // Whether this symbol has a value for the output file. This is
1406 // normally set to true during Layout::finalize, by
1407 // finalize_local_symbols. It will be false for a section symbol in
1408 // a merge section, as for such symbols we can not determine the
1409 // value to use in a relocation until we see the addend.
1410 bool has_output_value_
: 1;
1413 // This is used if has_output_value_ is true. Between
1414 // count_local_symbols and finalize_local_symbols, this is the
1415 // value in the input file. After finalize_local_symbols, it is
1416 // the value in the output file.
1418 // This is used if has_output_value_ is false. It points to the
1419 // information we need to get the value for a merge section.
1420 Merged_symbol_value
<size
>* merged_symbol_value
;
1424 // A GOT offset list. A symbol may have more than one GOT offset
1425 // (e.g., when mixing modules compiled with two different TLS models),
1426 // but will usually have at most one. GOT_TYPE identifies the type of
1427 // GOT entry; its values are specific to each target.
1429 class Got_offset_list
1433 : got_type_(-1U), got_offset_(0), got_next_(NULL
)
1436 Got_offset_list(unsigned int got_type
, unsigned int got_offset
)
1437 : got_type_(got_type
), got_offset_(got_offset
), got_next_(NULL
)
1442 if (this->got_next_
!= NULL
)
1444 delete this->got_next_
;
1445 this->got_next_
= NULL
;
1449 // Initialize the fields to their default values.
1453 this->got_type_
= -1U;
1454 this->got_offset_
= 0;
1455 this->got_next_
= NULL
;
1458 // Set the offset for the GOT entry of type GOT_TYPE.
1460 set_offset(unsigned int got_type
, unsigned int got_offset
)
1462 if (this->got_type_
== -1U)
1464 this->got_type_
= got_type
;
1465 this->got_offset_
= got_offset
;
1469 for (Got_offset_list
* g
= this; g
!= NULL
; g
= g
->got_next_
)
1471 if (g
->got_type_
== got_type
)
1473 g
->got_offset_
= got_offset
;
1477 Got_offset_list
* g
= new Got_offset_list(got_type
, got_offset
);
1478 g
->got_next_
= this->got_next_
;
1479 this->got_next_
= g
;
1483 // Return the offset for a GOT entry of type GOT_TYPE.
1485 get_offset(unsigned int got_type
) const
1487 for (const Got_offset_list
* g
= this; g
!= NULL
; g
= g
->got_next_
)
1489 if (g
->got_type_
== got_type
)
1490 return g
->got_offset_
;
1495 // Return a pointer to the list, or NULL if the list is empty.
1496 const Got_offset_list
*
1499 if (this->got_type_
== -1U)
1504 // Loop over all GOT offset entries, applying the function F to each.
1505 template<typename F
>
1507 for_all_got_offsets(F f
) const
1509 if (this->got_type_
== -1U)
1511 for (const Got_offset_list
* g
= this; g
!= NULL
; g
= g
->got_next_
)
1512 f(g
->got_type_
, g
->got_offset_
);
1516 unsigned int got_type_
;
1517 unsigned int got_offset_
;
1518 Got_offset_list
* got_next_
;
1521 // This type is used to modify relocations for -fsplit-stack. It is
1522 // indexed by relocation index, and means that the relocation at that
1523 // index should use the symbol from the vector, rather than the one
1524 // indicated by the relocation.
1526 class Reloc_symbol_changes
1529 Reloc_symbol_changes(size_t count
)
1534 set(size_t i
, Symbol
* sym
)
1535 { this->vec_
[i
] = sym
; }
1538 operator[](size_t i
) const
1539 { return this->vec_
[i
]; }
1542 std::vector
<Symbol
*> vec_
;
1545 // Type for mapping section index to uncompressed size.
1547 typedef std::map
<unsigned int, section_size_type
> Compressed_section_map
;
1549 // A regular object file. This is size and endian specific.
1551 template<int size
, bool big_endian
>
1552 class Sized_relobj
: public Relobj
1555 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Address
;
1556 typedef std::vector
<Symbol
*> Symbols
;
1557 typedef std::vector
<Symbol_value
<size
> > Local_values
;
1559 static const Address invalid_address
= static_cast<Address
>(0) - 1;
1561 Sized_relobj(const std::string
& name
, Input_file
* input_file
, off_t offset
,
1562 const typename
elfcpp::Ehdr
<size
, big_endian
>&);
1566 // Checks if the offset of input section SHNDX within its output
1567 // section is invalid.
1569 is_output_section_offset_invalid(unsigned int shndx
) const
1570 { return this->get_output_section_offset(shndx
) == invalid_address
; }
1572 // Set up the object file based on TARGET.
1575 { this->do_setup(); }
1577 // Return the number of symbols. This is only valid after
1578 // Object::add_symbols has been called.
1580 symbol_count() const
1581 { return this->local_symbol_count_
+ this->symbols_
.size(); }
1583 // If SYM is the index of a global symbol in the object file's
1584 // symbol table, return the Symbol object. Otherwise, return NULL.
1586 global_symbol(unsigned int sym
) const
1588 if (sym
>= this->local_symbol_count_
)
1590 gold_assert(sym
- this->local_symbol_count_
< this->symbols_
.size());
1591 return this->symbols_
[sym
- this->local_symbol_count_
];
1596 // Return the section index of symbol SYM. Set *VALUE to its value
1597 // in the object file. Set *IS_ORDINARY if this is an ordinary
1598 // section index, not a special code between SHN_LORESERVE and
1599 // SHN_HIRESERVE. Note that for a symbol which is not defined in
1600 // this object file, this will set *VALUE to 0 and return SHN_UNDEF;
1601 // it will not return the final value of the symbol in the link.
1603 symbol_section_and_value(unsigned int sym
, Address
* value
, bool* is_ordinary
);
1605 // Return a pointer to the Symbol_value structure which holds the
1606 // value of a local symbol.
1607 const Symbol_value
<size
>*
1608 local_symbol(unsigned int sym
) const
1610 gold_assert(sym
< this->local_values_
.size());
1611 return &this->local_values_
[sym
];
1614 // Return the index of local symbol SYM in the ordinary symbol
1615 // table. A value of -1U means that the symbol is not being output.
1617 symtab_index(unsigned int sym
) const
1619 gold_assert(sym
< this->local_values_
.size());
1620 return this->local_values_
[sym
].output_symtab_index();
1623 // Return the index of local symbol SYM in the dynamic symbol
1624 // table. A value of -1U means that the symbol is not being output.
1626 dynsym_index(unsigned int sym
) const
1628 gold_assert(sym
< this->local_values_
.size());
1629 return this->local_values_
[sym
].output_dynsym_index();
1632 // Return the input section index of local symbol SYM.
1634 local_symbol_input_shndx(unsigned int sym
, bool* is_ordinary
) const
1636 gold_assert(sym
< this->local_values_
.size());
1637 return this->local_values_
[sym
].input_shndx(is_ordinary
);
1640 // Record that local symbol SYM must be in the output symbol table.
1642 set_must_have_output_symtab_entry(unsigned int sym
)
1644 gold_assert(sym
< this->local_values_
.size());
1645 this->local_values_
[sym
].set_must_have_output_symtab_entry();
1648 // Record that local symbol SYM needs a dynamic symbol entry.
1650 set_needs_output_dynsym_entry(unsigned int sym
)
1652 gold_assert(sym
< this->local_values_
.size());
1653 this->local_values_
[sym
].set_needs_output_dynsym_entry();
1656 // Return whether the local symbol SYMNDX has a GOT offset.
1657 // For TLS symbols, the GOT entry will hold its tp-relative offset.
1659 local_has_got_offset(unsigned int symndx
, unsigned int got_type
) const
1661 Local_got_offsets::const_iterator p
=
1662 this->local_got_offsets_
.find(symndx
);
1663 return (p
!= this->local_got_offsets_
.end()
1664 && p
->second
->get_offset(got_type
) != -1U);
1667 // Return the GOT offset of the local symbol SYMNDX.
1669 local_got_offset(unsigned int symndx
, unsigned int got_type
) const
1671 Local_got_offsets::const_iterator p
=
1672 this->local_got_offsets_
.find(symndx
);
1673 gold_assert(p
!= this->local_got_offsets_
.end());
1674 unsigned int off
= p
->second
->get_offset(got_type
);
1675 gold_assert(off
!= -1U);
1679 // Set the GOT offset of the local symbol SYMNDX to GOT_OFFSET.
1681 set_local_got_offset(unsigned int symndx
, unsigned int got_type
,
1682 unsigned int got_offset
)
1684 Local_got_offsets::const_iterator p
=
1685 this->local_got_offsets_
.find(symndx
);
1686 if (p
!= this->local_got_offsets_
.end())
1687 p
->second
->set_offset(got_type
, got_offset
);
1690 Got_offset_list
* g
= new Got_offset_list(got_type
, got_offset
);
1691 std::pair
<Local_got_offsets::iterator
, bool> ins
=
1692 this->local_got_offsets_
.insert(std::make_pair(symndx
, g
));
1693 gold_assert(ins
.second
);
1697 // Return the GOT offset list for the local symbol SYMNDX.
1698 const Got_offset_list
*
1699 local_got_offset_list(unsigned int symndx
) const
1701 Local_got_offsets::const_iterator p
=
1702 this->local_got_offsets_
.find(symndx
);
1703 if (p
== this->local_got_offsets_
.end())
1708 // Return whether the local symbol SYMNDX has a PLT offset.
1710 local_has_plt_offset(unsigned int symndx
) const;
1712 // Return the PLT offset for a local symbol. It is an error to call
1713 // this if it doesn't have one.
1715 local_plt_offset(unsigned int symndx
) const;
1717 // Set the PLT offset of the local symbol SYMNDX.
1719 set_local_plt_offset(unsigned int symndx
, unsigned int plt_offset
);
1721 // Get the offset of input section SHNDX within its output section.
1722 // This is -1 if the input section requires a special mapping, such
1723 // as a merge section. The output section can be found in the
1724 // output_sections_ field of the parent class Relobj.
1726 get_output_section_offset(unsigned int shndx
) const
1728 gold_assert(shndx
< this->section_offsets_
.size());
1729 return this->section_offsets_
[shndx
];
1732 // Return the name of the symbol that spans the given offset in the
1733 // specified section in this object. This is used only for error
1734 // messages and is not particularly efficient.
1736 get_symbol_location_info(unsigned int shndx
, off_t offset
,
1737 Symbol_location_info
* info
);
1739 // Look for a kept section corresponding to the given discarded section,
1740 // and return its output address. This is used only for relocations in
1741 // debugging sections.
1743 map_to_kept_section(unsigned int shndx
, bool* found
) const;
1750 // Read the symbols.
1752 do_read_symbols(Read_symbols_data
*);
1754 // Return the number of local symbols.
1756 do_local_symbol_count() const
1757 { return this->local_symbol_count_
; }
1759 // Lay out the input sections.
1761 do_layout(Symbol_table
*, Layout
*, Read_symbols_data
*);
1763 // Layout sections whose layout was deferred while waiting for
1764 // input files from a plugin.
1766 do_layout_deferred_sections(Layout
*);
1768 // Add the symbols to the symbol table.
1770 do_add_symbols(Symbol_table
*, Read_symbols_data
*, Layout
*);
1772 Archive::Should_include
1773 do_should_include_member(Symbol_table
* symtab
, Layout
*, Read_symbols_data
*,
1778 do_read_relocs(Read_relocs_data
*);
1780 // Process the relocs to find list of referenced sections. Used only
1781 // during garbage collection.
1783 do_gc_process_relocs(Symbol_table
*, Layout
*, Read_relocs_data
*);
1785 // Scan the relocs and adjust the symbol table.
1787 do_scan_relocs(Symbol_table
*, Layout
*, Read_relocs_data
*);
1789 // Count the local symbols.
1791 do_count_local_symbols(Stringpool_template
<char>*,
1792 Stringpool_template
<char>*);
1794 // Finalize the local symbols.
1796 do_finalize_local_symbols(unsigned int, off_t
, Symbol_table
*);
1798 // Set the offset where local dynamic symbol information will be stored.
1800 do_set_local_dynsym_indexes(unsigned int);
1802 // Set the offset where local dynamic symbol information will be stored.
1804 do_set_local_dynsym_offset(off_t
);
1806 // Relocate the input sections and write out the local symbols.
1808 do_relocate(const Symbol_table
* symtab
, const Layout
*, Output_file
* of
);
1810 // Get the size of a section.
1812 do_section_size(unsigned int shndx
)
1813 { return this->elf_file_
.section_size(shndx
); }
1815 // Get the name of a section.
1817 do_section_name(unsigned int shndx
)
1818 { return this->elf_file_
.section_name(shndx
); }
1820 // Return the location of the contents of a section.
1822 do_section_contents(unsigned int shndx
)
1823 { return this->elf_file_
.section_contents(shndx
); }
1825 // Return section flags.
1827 do_section_flags(unsigned int shndx
);
1829 // Return section entsize.
1831 do_section_entsize(unsigned int shndx
);
1833 // Return section address.
1835 do_section_address(unsigned int shndx
)
1836 { return this->elf_file_
.section_addr(shndx
); }
1838 // Return section type.
1840 do_section_type(unsigned int shndx
)
1841 { return this->elf_file_
.section_type(shndx
); }
1843 // Return the section link field.
1845 do_section_link(unsigned int shndx
)
1846 { return this->elf_file_
.section_link(shndx
); }
1848 // Return the section info field.
1850 do_section_info(unsigned int shndx
)
1851 { return this->elf_file_
.section_info(shndx
); }
1853 // Return the section alignment.
1855 do_section_addralign(unsigned int shndx
)
1856 { return this->elf_file_
.section_addralign(shndx
); }
1858 // Return the Xindex structure to use.
1860 do_initialize_xindex();
1862 // Get symbol counts.
1864 do_get_global_symbol_counts(const Symbol_table
*, size_t*, size_t*) const;
1866 // Get the global symbols.
1868 do_get_global_symbols() const
1869 { return &this->symbols_
; }
1871 // Get the offset of a section.
1873 do_output_section_offset(unsigned int shndx
) const
1875 Address off
= this->get_output_section_offset(shndx
);
1876 if (off
== invalid_address
)
1881 // Set the offset of a section.
1883 do_set_section_offset(unsigned int shndx
, uint64_t off
)
1885 gold_assert(shndx
< this->section_offsets_
.size());
1886 this->section_offsets_
[shndx
] =
1887 (off
== static_cast<uint64_t>(-1)
1889 : convert_types
<Address
, uint64_t>(off
));
1892 // Adjust a section index if necessary.
1894 adjust_shndx(unsigned int shndx
)
1896 if (shndx
>= elfcpp::SHN_LORESERVE
)
1897 shndx
+= this->elf_file_
.large_shndx_offset();
1901 // Initialize input to output maps for section symbols in merged
1904 initialize_input_to_output_maps();
1906 // Free the input to output maps for section symbols in merged
1909 free_input_to_output_maps();
1911 // Return symbol table section index.
1913 symtab_shndx() const
1914 { return this->symtab_shndx_
; }
1916 // Allow a child class to access the ELF file.
1917 elfcpp::Elf_file
<size
, big_endian
, Object
>*
1919 { return &this->elf_file_
; }
1921 // Allow a child class to access the local values.
1924 { return &this->local_values_
; }
1926 // Views and sizes when relocating.
1929 unsigned char* view
;
1930 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
;
1932 section_size_type view_size
;
1933 bool is_input_output_view
;
1934 bool is_postprocessing_view
;
1937 typedef std::vector
<View_size
> Views
;
1939 // This may be overriden by a child class.
1941 do_relocate_sections(const Symbol_table
* symtab
, const Layout
* layout
,
1942 const unsigned char* pshdrs
, Output_file
* of
,
1945 // Allow a child to set output local symbol count.
1947 set_output_local_symbol_count(unsigned int value
)
1948 { this->output_local_symbol_count_
= value
; }
1950 // Return TRUE if the section is a compressed debug section, and set
1951 // *UNCOMPRESSED_SIZE to the size of the uncompressed data.
1953 do_section_is_compressed(unsigned int shndx
,
1954 section_size_type
* uncompressed_size
) const
1956 if (this->compressed_sections_
== NULL
)
1958 Compressed_section_map::const_iterator p
=
1959 this->compressed_sections_
->find(shndx
);
1960 if (p
!= this->compressed_sections_
->end())
1962 if (uncompressed_size
!= NULL
)
1963 *uncompressed_size
= p
->second
;
1971 typedef Sized_relobj
<size
, big_endian
> This
;
1972 static const int ehdr_size
= elfcpp::Elf_sizes
<size
>::ehdr_size
;
1973 static const int shdr_size
= elfcpp::Elf_sizes
<size
>::shdr_size
;
1974 static const int sym_size
= elfcpp::Elf_sizes
<size
>::sym_size
;
1975 typedef elfcpp::Shdr
<size
, big_endian
> Shdr
;
1977 // To keep track of discarded comdat sections, we need to map a member
1978 // section index to the object and section index of the corresponding
1980 struct Kept_comdat_section
1982 Kept_comdat_section(Relobj
* a_object
, unsigned int a_shndx
)
1983 : object(a_object
), shndx(a_shndx
)
1988 typedef std::map
<unsigned int, Kept_comdat_section
>
1989 Kept_comdat_section_table
;
1991 // Find the SHT_SYMTAB section, given the section headers.
1993 find_symtab(const unsigned char* pshdrs
);
1995 // Return whether SHDR has the right flags for a GNU style exception
1998 check_eh_frame_flags(const elfcpp::Shdr
<size
, big_endian
>* shdr
) const;
2000 // Return whether there is a section named .eh_frame which might be
2001 // a GNU style exception frame section.
2003 find_eh_frame(const unsigned char* pshdrs
, const char* names
,
2004 section_size_type names_size
) const;
2006 // Whether to include a section group in the link.
2008 include_section_group(Symbol_table
*, Layout
*, unsigned int, const char*,
2009 const unsigned char*, const char *, section_size_type
,
2010 std::vector
<bool>*);
2012 // Whether to include a linkonce section in the link.
2014 include_linkonce_section(Layout
*, unsigned int, const char*,
2015 const elfcpp::Shdr
<size
, big_endian
>&);
2017 // Layout an input section.
2019 layout_section(Layout
* layout
, unsigned int shndx
, const char* name
,
2020 typename
This::Shdr
& shdr
, unsigned int reloc_shndx
,
2021 unsigned int reloc_type
);
2023 // Write section data to the output file. Record the views and
2024 // sizes in VIEWS for use when relocating.
2026 write_sections(const unsigned char* pshdrs
, Output_file
*, Views
*);
2028 // Relocate the sections in the output file.
2030 relocate_sections(const Symbol_table
* symtab
, const Layout
* layout
,
2031 const unsigned char* pshdrs
, Output_file
* of
,
2033 { this->do_relocate_sections(symtab
, layout
, pshdrs
, of
, pviews
); }
2035 // Scan the input relocations for --emit-relocs.
2037 emit_relocs_scan(Symbol_table
*, Layout
*, const unsigned char* plocal_syms
,
2038 const Read_relocs_data::Relocs_list::iterator
&);
2040 // Scan the input relocations for --emit-relocs, templatized on the
2041 // type of the relocation section.
2042 template<int sh_type
>
2044 emit_relocs_scan_reltype(Symbol_table
*, Layout
*,
2045 const unsigned char* plocal_syms
,
2046 const Read_relocs_data::Relocs_list::iterator
&,
2047 Relocatable_relocs
*);
2049 // Emit the relocs for --emit-relocs.
2051 emit_relocs(const Relocate_info
<size
, big_endian
>*, unsigned int,
2052 unsigned int sh_type
, const unsigned char* prelocs
,
2053 size_t reloc_count
, Output_section
*, Address output_offset
,
2054 unsigned char* view
, Address address
,
2055 section_size_type view_size
,
2056 unsigned char* reloc_view
, section_size_type reloc_view_size
);
2058 // Emit the relocs for --emit-relocs, templatized on the type of the
2059 // relocation section.
2060 template<int sh_type
>
2062 emit_relocs_reltype(const Relocate_info
<size
, big_endian
>*, unsigned int,
2063 const unsigned char* prelocs
, size_t reloc_count
,
2064 Output_section
*, Address output_offset
,
2065 unsigned char* view
, Address address
,
2066 section_size_type view_size
,
2067 unsigned char* reloc_view
,
2068 section_size_type reloc_view_size
);
2070 // Scan the input relocations for --incremental.
2072 incremental_relocs_scan(const Read_relocs_data::Relocs_list::iterator
&);
2074 // Scan the input relocations for --incremental, templatized on the
2075 // type of the relocation section.
2076 template<int sh_type
>
2078 incremental_relocs_scan_reltype(
2079 const Read_relocs_data::Relocs_list::iterator
&);
2082 incremental_relocs_write(const Relocate_info
<size
, big_endian
>*,
2083 unsigned int sh_type
,
2084 const unsigned char* prelocs
,
2087 Address output_offset
,
2090 template<int sh_type
>
2092 incremental_relocs_write_reltype(const Relocate_info
<size
, big_endian
>*,
2093 const unsigned char* prelocs
,
2096 Address output_offset
,
2099 // A type shared by split_stack_adjust_reltype and find_functions.
2100 typedef std::map
<section_offset_type
, section_size_type
> Function_offsets
;
2102 // Check for -fsplit-stack routines calling non-split-stack routines.
2104 split_stack_adjust(const Symbol_table
*, const unsigned char* pshdrs
,
2105 unsigned int sh_type
, unsigned int shndx
,
2106 const unsigned char* prelocs
, size_t reloc_count
,
2107 unsigned char* view
, section_size_type view_size
,
2108 Reloc_symbol_changes
** reloc_map
);
2110 template<int sh_type
>
2112 split_stack_adjust_reltype(const Symbol_table
*, const unsigned char* pshdrs
,
2113 unsigned int shndx
, const unsigned char* prelocs
,
2114 size_t reloc_count
, unsigned char* view
,
2115 section_size_type view_size
,
2116 Reloc_symbol_changes
** reloc_map
);
2118 // Find all functions in a section.
2120 find_functions(const unsigned char* pshdrs
, unsigned int shndx
,
2123 // Write out the local symbols.
2125 write_local_symbols(Output_file
*,
2126 const Stringpool_template
<char>*,
2127 const Stringpool_template
<char>*,
2128 Output_symtab_xindex
*,
2129 Output_symtab_xindex
*);
2131 // Clear the local symbol information.
2133 clear_local_symbols()
2135 this->local_values_
.clear();
2136 this->local_got_offsets_
.clear();
2137 this->local_plt_offsets_
.clear();
2140 // Record a mapping from discarded section SHNDX to the corresponding
2143 set_kept_comdat_section(unsigned int shndx
, Relobj
* kept_object
,
2144 unsigned int kept_shndx
)
2146 Kept_comdat_section
kept(kept_object
, kept_shndx
);
2147 this->kept_comdat_sections_
.insert(std::make_pair(shndx
, kept
));
2150 // Find the kept section corresponding to the discarded section
2151 // SHNDX. Return true if found.
2153 get_kept_comdat_section(unsigned int shndx
, Relobj
** kept_object
,
2154 unsigned int* kept_shndx
) const
2156 typename
Kept_comdat_section_table::const_iterator p
=
2157 this->kept_comdat_sections_
.find(shndx
);
2158 if (p
== this->kept_comdat_sections_
.end())
2160 *kept_object
= p
->second
.object
;
2161 *kept_shndx
= p
->second
.shndx
;
2165 // The GOT offsets of local symbols. This map also stores GOT offsets
2166 // for tp-relative offsets for TLS symbols.
2167 typedef Unordered_map
<unsigned int, Got_offset_list
*> Local_got_offsets
;
2169 // The PLT offsets of local symbols.
2170 typedef Unordered_map
<unsigned int, unsigned int> Local_plt_offsets
;
2172 // Saved information for sections whose layout was deferred.
2173 struct Deferred_layout
2175 static const int shdr_size
= elfcpp::Elf_sizes
<size
>::shdr_size
;
2176 Deferred_layout(unsigned int shndx
, const char* name
,
2177 const unsigned char* pshdr
,
2178 unsigned int reloc_shndx
, unsigned int reloc_type
)
2179 : shndx_(shndx
), name_(name
), reloc_shndx_(reloc_shndx
),
2180 reloc_type_(reloc_type
)
2182 memcpy(this->shdr_data_
, pshdr
, shdr_size
);
2184 unsigned int shndx_
;
2186 unsigned int reloc_shndx_
;
2187 unsigned int reloc_type_
;
2188 unsigned char shdr_data_
[shdr_size
];
2191 // General access to the ELF file.
2192 elfcpp::Elf_file
<size
, big_endian
, Object
> elf_file_
;
2193 // Index of SHT_SYMTAB section.
2194 unsigned int symtab_shndx_
;
2195 // The number of local symbols.
2196 unsigned int local_symbol_count_
;
2197 // The number of local symbols which go into the output file.
2198 unsigned int output_local_symbol_count_
;
2199 // The number of local symbols which go into the output file's dynamic
2201 unsigned int output_local_dynsym_count_
;
2202 // The entries in the symbol table for the external symbols.
2204 // Number of symbols defined in object file itself.
2205 size_t defined_count_
;
2206 // File offset for local symbols.
2207 off_t local_symbol_offset_
;
2208 // File offset for local dynamic symbols.
2209 off_t local_dynsym_offset_
;
2210 // Values of local symbols.
2211 Local_values local_values_
;
2212 // GOT offsets for local non-TLS symbols, and tp-relative offsets
2213 // for TLS symbols, indexed by symbol number.
2214 Local_got_offsets local_got_offsets_
;
2215 // PLT offsets for local symbols.
2216 Local_plt_offsets local_plt_offsets_
;
2217 // For each input section, the offset of the input section in its
2218 // output section. This is INVALID_ADDRESS if the input section requires a
2220 std::vector
<Address
> section_offsets_
;
2221 // Table mapping discarded comdat sections to corresponding kept sections.
2222 Kept_comdat_section_table kept_comdat_sections_
;
2223 // Whether this object has a GNU style .eh_frame section.
2225 // If this object has a GNU style .eh_frame section that is discarded in
2226 // output, record the index here. Otherwise it is -1U.
2227 unsigned int discarded_eh_frame_shndx_
;
2228 // The list of sections whose layout was deferred.
2229 std::vector
<Deferred_layout
> deferred_layout_
;
2230 // The list of relocation sections whose layout was deferred.
2231 std::vector
<Deferred_layout
> deferred_layout_relocs_
;
2232 // For compressed debug sections, map section index to uncompressed size.
2233 Compressed_section_map
* compressed_sections_
;
2236 // A class to manage the list of all objects.
2242 : relobj_list_(), dynobj_list_(), sonames_(), cref_(NULL
)
2245 // The type of the list of input relocateable objects.
2246 typedef std::vector
<Relobj
*> Relobj_list
;
2247 typedef Relobj_list::const_iterator Relobj_iterator
;
2249 // The type of the list of input dynamic objects.
2250 typedef std::vector
<Dynobj
*> Dynobj_list
;
2251 typedef Dynobj_list::const_iterator Dynobj_iterator
;
2253 // Add an object to the list. Return true if all is well, or false
2254 // if this object should be ignored.
2256 add_object(Object
*);
2258 // Start processing an archive.
2260 archive_start(Archive
*);
2262 // Stop processing an archive.
2264 archive_stop(Archive
*);
2266 // For each dynamic object, check whether we've seen all of its
2267 // explicit dependencies.
2269 check_dynamic_dependencies() const;
2271 // Return whether an object was found in the system library
2274 found_in_system_library_directory(const Object
*) const;
2276 // Print symbol counts.
2278 print_symbol_counts(const Symbol_table
*) const;
2280 // Print a cross reference table.
2282 print_cref(const Symbol_table
*, FILE*) const;
2284 // Iterate over all regular objects.
2287 relobj_begin() const
2288 { return this->relobj_list_
.begin(); }
2292 { return this->relobj_list_
.end(); }
2294 // Iterate over all dynamic objects.
2297 dynobj_begin() const
2298 { return this->dynobj_list_
.begin(); }
2302 { return this->dynobj_list_
.end(); }
2304 // Return whether we have seen any dynamic objects.
2307 { return !this->dynobj_list_
.empty(); }
2309 // Return the number of non dynamic objects.
2311 number_of_relobjs() const
2312 { return this->relobj_list_
.size(); }
2314 // Return the number of input objects.
2316 number_of_input_objects() const
2317 { return this->relobj_list_
.size() + this->dynobj_list_
.size(); }
2320 Input_objects(const Input_objects
&);
2321 Input_objects
& operator=(const Input_objects
&);
2323 // The list of ordinary objects included in the link.
2324 Relobj_list relobj_list_
;
2325 // The list of dynamic objects included in the link.
2326 Dynobj_list dynobj_list_
;
2327 // SONAMEs that we have seen.
2328 Unordered_set
<std::string
> sonames_
;
2329 // Manage cross-references if requested.
2333 // Some of the information we pass to the relocation routines. We
2334 // group this together to avoid passing a dozen different arguments.
2336 template<int size
, bool big_endian
>
2337 struct Relocate_info
2340 const Symbol_table
* symtab
;
2342 const Layout
* layout
;
2343 // Object being relocated.
2344 Sized_relobj
<size
, big_endian
>* object
;
2345 // Section index of relocation section.
2346 unsigned int reloc_shndx
;
2347 // Section header of relocation section.
2348 const unsigned char* reloc_shdr
;
2349 // Section index of section being relocated.
2350 unsigned int data_shndx
;
2351 // Section header of data section.
2352 const unsigned char* data_shdr
;
2354 // Return a string showing the location of a relocation. This is
2355 // only used for error messages.
2357 location(size_t relnum
, off_t reloffset
) const;
2360 // This is used to represent a section in an object and is used as the
2361 // key type for various section maps.
2362 typedef std::pair
<Object
*, unsigned int> Section_id
;
2364 // This is similar to Section_id but is used when the section
2365 // pointers are const.
2366 typedef std::pair
<const Object
*, unsigned int> Const_section_id
;
2368 // The hash value is based on the address of an object in memory during
2369 // linking. It is okay to use this for looking up sections but never use
2370 // this in an unordered container that we want to traverse in a repeatable
2373 struct Section_id_hash
2375 size_t operator()(const Section_id
& loc
) const
2376 { return reinterpret_cast<uintptr_t>(loc
.first
) ^ loc
.second
; }
2379 struct Const_section_id_hash
2381 size_t operator()(const Const_section_id
& loc
) const
2382 { return reinterpret_cast<uintptr_t>(loc
.first
) ^ loc
.second
; }
2385 // Return whether INPUT_FILE contains an ELF object start at file
2386 // offset OFFSET. This sets *START to point to a view of the start of
2387 // the file. It sets *READ_SIZE to the number of bytes in the view.
2390 is_elf_object(Input_file
* input_file
, off_t offset
,
2391 const unsigned char** start
, int *read_size
);
2393 // Return an Object appropriate for the input file. P is BYTES long,
2394 // and holds the ELF header. If PUNCONFIGURED is not NULL, then if
2395 // this sees an object the linker is not configured to support, it
2396 // sets *PUNCONFIGURED to true and returns NULL without giving an
2400 make_elf_object(const std::string
& name
, Input_file
*,
2401 off_t offset
, const unsigned char* p
,
2402 section_offset_type bytes
, bool* punconfigured
);
2404 } // end namespace gold
2406 #endif // !defined(GOLD_OBJECT_H)