1 // symtab.h -- the gold symbol table -*- C++ -*-
3 // Copyright 2006, 2007 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
31 #include "parameters.h"
32 #include "stringpool.h"
43 template<int size
, bool big_endian
>
46 template<int size
, bool big_endian
>
56 // The base class of an entry in the symbol table. The symbol table
57 // can have a lot of entries, so we don't want this class to big.
58 // Size dependent fields can be found in the template class
59 // Sized_symbol. Targets may support their own derived classes.
64 // Because we want the class to be small, we don't use any virtual
65 // functions. But because symbols can be defined in different
66 // places, we need to classify them. This enum is the different
67 // sources of symbols we support.
70 // Symbol defined in a relocatable or dynamic input file--this is
71 // the most common case.
73 // Symbol defined in an Output_data, a special section created by
76 // Symbol defined in an Output_segment, with no associated
79 // Symbol value is constant.
83 // When the source is IN_OUTPUT_SEGMENT, we need to describe what
85 enum Segment_offset_base
87 // From the start of the segment.
89 // From the end of the segment.
91 // From the filesz of the segment--i.e., after the loaded bytes
92 // but before the bytes which are allocated but zeroed.
96 // Return the symbol name.
99 { return this->name_
; }
101 // Return the symbol version. This will return NULL for an
102 // unversioned symbol.
105 { return this->version_
; }
107 // Return the symbol source.
110 { return this->source_
; }
112 // Return the object with which this symbol is associated.
116 gold_assert(this->source_
== FROM_OBJECT
);
117 return this->u_
.from_object
.object
;
120 // Return the index of the section in the input relocatable or
121 // dynamic object file.
125 gold_assert(this->source_
== FROM_OBJECT
);
126 return this->u_
.from_object
.shndx
;
129 // Return the output data section with which this symbol is
130 // associated, if the symbol was specially defined with respect to
131 // an output data section.
135 gold_assert(this->source_
== IN_OUTPUT_DATA
);
136 return this->u_
.in_output_data
.output_data
;
139 // If this symbol was defined with respect to an output data
140 // section, return whether the value is an offset from end.
142 offset_is_from_end() const
144 gold_assert(this->source_
== IN_OUTPUT_DATA
);
145 return this->u_
.in_output_data
.offset_is_from_end
;
148 // Return the output segment with which this symbol is associated,
149 // if the symbol was specially defined with respect to an output
152 output_segment() const
154 gold_assert(this->source_
== IN_OUTPUT_SEGMENT
);
155 return this->u_
.in_output_segment
.output_segment
;
158 // If this symbol was defined with respect to an output segment,
159 // return the offset base.
163 gold_assert(this->source_
== IN_OUTPUT_SEGMENT
);
164 return this->u_
.in_output_segment
.offset_base
;
167 // Return the symbol binding.
170 { return this->binding_
; }
172 // Return the symbol type.
175 { return this->type_
; }
177 // Return the symbol visibility.
180 { return this->visibility_
; }
182 // Return the non-visibility part of the st_other field.
185 { return this->nonvis_
; }
187 // Return whether this symbol is a forwarder. This will never be
188 // true of a symbol found in the hash table, but may be true of
189 // symbol pointers attached to object files.
192 { return this->is_forwarder_
; }
194 // Mark this symbol as a forwarder.
197 { this->is_forwarder_
= true; }
199 // Return whether this symbol has an alias in the weak aliases table
203 { return this->has_alias_
; }
205 // Mark this symbol as having an alias.
208 { this->has_alias_
= true; }
210 // Return whether this symbol needs an entry in the dynamic symbol
213 needs_dynsym_entry() const
215 return (this->needs_dynsym_entry_
216 || (this->in_reg() && this->in_dyn()));
219 // Mark this symbol as needing an entry in the dynamic symbol table.
221 set_needs_dynsym_entry()
222 { this->needs_dynsym_entry_
= true; }
224 // Return whether this symbol should be added to the dynamic symbol
227 should_add_dynsym_entry() const;
229 // Return whether this symbol has been seen in a regular object.
232 { return this->in_reg_
; }
234 // Mark this symbol as having been seen in a regular object.
237 { this->in_reg_
= true; }
239 // Return whether this symbol has been seen in a dynamic object.
242 { return this->in_dyn_
; }
244 // Mark this symbol as having been seen in a dynamic object.
247 { this->in_dyn_
= true; }
249 // Return the index of this symbol in the output file symbol table.
250 // A value of -1U means that this symbol is not going into the
251 // output file. This starts out as zero, and is set to a non-zero
252 // value by Symbol_table::finalize. It is an error to ask for the
253 // symbol table index before it has been set.
257 gold_assert(this->symtab_index_
!= 0);
258 return this->symtab_index_
;
261 // Set the index of the symbol in the output file symbol table.
263 set_symtab_index(unsigned int index
)
265 gold_assert(index
!= 0);
266 this->symtab_index_
= index
;
269 // Return whether this symbol already has an index in the output
270 // file symbol table.
272 has_symtab_index() const
273 { return this->symtab_index_
!= 0; }
275 // Return the index of this symbol in the dynamic symbol table. A
276 // value of -1U means that this symbol is not going into the dynamic
277 // symbol table. This starts out as zero, and is set to a non-zero
278 // during Layout::finalize. It is an error to ask for the dynamic
279 // symbol table index before it has been set.
283 gold_assert(this->dynsym_index_
!= 0);
284 return this->dynsym_index_
;
287 // Set the index of the symbol in the dynamic symbol table.
289 set_dynsym_index(unsigned int index
)
291 gold_assert(index
!= 0);
292 this->dynsym_index_
= index
;
295 // Return whether this symbol already has an index in the dynamic
298 has_dynsym_index() const
299 { return this->dynsym_index_
!= 0; }
301 // Return whether this symbol has an entry in the GOT section.
303 has_got_offset() const
304 { return this->has_got_offset_
; }
306 // Return the offset into the GOT section of this symbol.
310 gold_assert(this->has_got_offset());
311 return this->got_offset_
;
314 // Set the GOT offset of this symbol.
316 set_got_offset(unsigned int got_offset
)
318 this->has_got_offset_
= true;
319 this->got_offset_
= got_offset
;
322 // Return whether this symbol has an entry in the PLT section.
324 has_plt_offset() const
325 { return this->has_plt_offset_
; }
327 // Return the offset into the PLT section of this symbol.
331 gold_assert(this->has_plt_offset());
332 return this->plt_offset_
;
335 // Set the PLT offset of this symbol.
337 set_plt_offset(unsigned int plt_offset
)
339 this->has_plt_offset_
= true;
340 this->plt_offset_
= plt_offset
;
343 // Return whether this dynamic symbol needs a special value in the
344 // dynamic symbol table.
346 needs_dynsym_value() const
347 { return this->needs_dynsym_value_
; }
349 // Set that this dynamic symbol needs a special value in the dynamic
352 set_needs_dynsym_value()
354 gold_assert(this->object()->is_dynamic());
355 this->needs_dynsym_value_
= true;
358 // Return true if the final value of this symbol is known at link
361 final_value_is_known() const;
363 // Return whether this is a defined symbol (not undefined or
368 return (this->source_
!= FROM_OBJECT
369 || (this->shndx() != elfcpp::SHN_UNDEF
370 && this->shndx() != elfcpp::SHN_COMMON
));
373 // Return true if this symbol is from a dynamic object.
375 is_from_dynobj() const
377 return this->source_
== FROM_OBJECT
&& this->object()->is_dynamic();
380 // Return whether this is an undefined symbol.
384 return this->source_
== FROM_OBJECT
&& this->shndx() == elfcpp::SHN_UNDEF
;
387 // Return whether this is a common symbol.
391 return (this->source_
== FROM_OBJECT
392 && (this->shndx() == elfcpp::SHN_COMMON
393 || this->type_
== elfcpp::STT_COMMON
));
396 // Return whether this symbol can be seen outside this object.
398 is_externally_visible() const
400 return (this->visibility_
== elfcpp::STV_DEFAULT
401 || this->visibility_
== elfcpp::STV_PROTECTED
);
404 // Return true if this symbol can be preempted by a definition in
405 // another link unit.
407 is_preemptible() const
409 // It doesn't make sense to ask whether a symbol defined in
410 // another object is preemptible.
411 gold_assert(!this->is_from_dynobj());
413 return (this->visibility_
!= elfcpp::STV_INTERNAL
414 && this->visibility_
!= elfcpp::STV_HIDDEN
415 && this->visibility_
!= elfcpp::STV_PROTECTED
416 && parameters
->output_is_shared()
417 && !parameters
->symbolic());
420 // Return true if this symbol is a function that needs a PLT entry.
421 // If the symbol is defined in a dynamic object or if it is subject
422 // to pre-emption, we need to make a PLT entry.
424 needs_plt_entry() const
426 return (this->type() == elfcpp::STT_FUNC
427 && (this->is_from_dynobj() || this->is_preemptible()));
430 // Given a direct absolute or pc-relative static relocation against
431 // the global symbol, this function returns whether a dynamic relocation
435 needs_dynamic_reloc(bool is_absolute_ref
, bool is_function_call
) const
437 // An absolute reference within a position-independent output file
438 // will need a dynamic relocaion.
439 if (is_absolute_ref
&& parameters
->output_is_position_independent())
442 // A function call that can branch to a local PLT entry does not need
443 // a dynamic relocation.
444 if (is_function_call
&& this->has_plt_offset())
447 // A reference to any PLT entry in a non-position-independent executable
448 // does not need a dynamic relocation.
449 if (!parameters
->output_is_position_independent()
450 && this->has_plt_offset())
453 // A reference to a symbol defined in a dynamic object or to a
454 // symbol that is preemptible will need a dynamic relocation.
455 if (this->is_from_dynobj() || this->is_preemptible())
458 // For all other cases, return FALSE.
462 // Given a direct absolute static relocation against
463 // the global symbol, where a dynamic relocation is needed, this
464 // function returns whether a relative dynamic relocation can be used.
465 // The caller must determine separately whether the static relocation
466 // is compatible with a relative relocation.
469 can_use_relative_reloc(bool is_function_call
) const
471 // A function call that can branch to a local PLT entry can
472 // use a RELATIVE relocation.
473 if (is_function_call
&& this->has_plt_offset())
476 // A reference to a symbol defined in a dynamic object or to a
477 // symbol that is preemptible can not use a RELATIVE relocaiton.
478 if (this->is_from_dynobj() || this->is_preemptible())
481 // For all other cases, return TRUE.
485 // Return whether there should be a warning for references to this
489 { return this->has_warning_
; }
491 // Mark this symbol as having a warning.
494 { this->has_warning_
= true; }
496 // Return whether this symbol is defined by a COPY reloc from a
499 is_copied_from_dynobj() const
500 { return this->is_copied_from_dynobj_
; }
502 // Mark this symbol as defined by a COPY reloc.
504 set_is_copied_from_dynobj()
505 { this->is_copied_from_dynobj_
= true; }
507 // Mark this symbol as needing its value written to the GOT even when
508 // the value is subject to dynamic relocation (e.g., when the target
509 // uses a RELATIVE relocation for the GOT entry).
511 set_needs_value_in_got()
512 { this->needs_value_in_got_
= true; }
514 // Return whether this symbol needs its value written to the GOT even
515 // when the value is subject to dynamic relocation.
517 needs_value_in_got() const
518 { return this->needs_value_in_got_
; }
521 // Instances of this class should always be created at a specific
524 { memset(this, 0, sizeof *this); }
526 // Initialize the general fields.
528 init_fields(const char* name
, const char* version
,
529 elfcpp::STT type
, elfcpp::STB binding
,
530 elfcpp::STV visibility
, unsigned char nonvis
);
532 // Initialize fields from an ELF symbol in OBJECT.
533 template<int size
, bool big_endian
>
535 init_base(const char *name
, const char* version
, Object
* object
,
536 const elfcpp::Sym
<size
, big_endian
>&);
538 // Initialize fields for an Output_data.
540 init_base(const char* name
, Output_data
*, elfcpp::STT
, elfcpp::STB
,
541 elfcpp::STV
, unsigned char nonvis
, bool offset_is_from_end
);
543 // Initialize fields for an Output_segment.
545 init_base(const char* name
, Output_segment
* os
, elfcpp::STT type
,
546 elfcpp::STB binding
, elfcpp::STV visibility
,
547 unsigned char nonvis
, Segment_offset_base offset_base
);
549 // Initialize fields for a constant.
551 init_base(const char* name
, elfcpp::STT type
, elfcpp::STB binding
,
552 elfcpp::STV visibility
, unsigned char nonvis
);
554 // Override existing symbol.
555 template<int size
, bool big_endian
>
557 override_base(const elfcpp::Sym
<size
, big_endian
>&, Object
* object
,
558 const char* version
);
560 // Override existing symbol with a special symbol.
562 override_base_with_special(const Symbol
* from
);
565 Symbol(const Symbol
&);
566 Symbol
& operator=(const Symbol
&);
568 // Symbol name (expected to point into a Stringpool).
570 // Symbol version (expected to point into a Stringpool). This may
572 const char* version_
;
576 // This struct is used if SOURCE_ == FROM_OBJECT.
579 // Object in which symbol is defined, or in which it was first
582 // Section number in object_ in which symbol is defined.
586 // This struct is used if SOURCE_ == IN_OUTPUT_DATA.
589 // Output_data in which symbol is defined. Before
590 // Layout::finalize the symbol's value is an offset within the
592 Output_data
* output_data
;
593 // True if the offset is from the end, false if the offset is
594 // from the beginning.
595 bool offset_is_from_end
;
598 // This struct is used if SOURCE_ == IN_OUTPUT_SEGMENT.
601 // Output_segment in which the symbol is defined. Before
602 // Layout::finalize the symbol's value is an offset.
603 Output_segment
* output_segment
;
604 // The base to use for the offset before Layout::finalize.
605 Segment_offset_base offset_base
;
609 // The index of this symbol in the output file. If the symbol is
610 // not going into the output file, this value is -1U. This field
611 // starts as always holding zero. It is set to a non-zero value by
612 // Symbol_table::finalize.
613 unsigned int symtab_index_
;
615 // The index of this symbol in the dynamic symbol table. If the
616 // symbol is not going into the dynamic symbol table, this value is
617 // -1U. This field starts as always holding zero. It is set to a
618 // non-zero value during Layout::finalize.
619 unsigned int dynsym_index_
;
621 // If this symbol has an entry in the GOT section (has_got_offset_
622 // is true), this is the offset from the start of the GOT section.
623 unsigned int got_offset_
;
625 // If this symbol has an entry in the PLT section (has_plt_offset_
626 // is true), then this is the offset from the start of the PLT
628 unsigned int plt_offset_
;
631 elfcpp::STT type_
: 4;
633 elfcpp::STB binding_
: 4;
634 // Symbol visibility.
635 elfcpp::STV visibility_
: 2;
636 // Rest of symbol st_other field.
637 unsigned int nonvis_
: 6;
638 // The type of symbol.
640 // True if this symbol always requires special target-specific
642 bool is_target_special_
: 1;
643 // True if this is the default version of the symbol.
645 // True if this symbol really forwards to another symbol. This is
646 // used when we discover after the fact that two different entries
647 // in the hash table really refer to the same symbol. This will
648 // never be set for a symbol found in the hash table, but may be set
649 // for a symbol found in the list of symbols attached to an Object.
650 // It forwards to the symbol found in the forwarders_ map of
652 bool is_forwarder_
: 1;
653 // True if the symbol has an alias in the weak_aliases table in
656 // True if this symbol needs to be in the dynamic symbol table.
657 bool needs_dynsym_entry_
: 1;
658 // True if we've seen this symbol in a regular object.
660 // True if we've seen this symbol in a dynamic object.
662 // True if the symbol has an entry in the GOT section.
663 bool has_got_offset_
: 1;
664 // True if the symbol has an entry in the PLT section.
665 bool has_plt_offset_
: 1;
666 // True if this is a dynamic symbol which needs a special value in
667 // the dynamic symbol table.
668 bool needs_dynsym_value_
: 1;
669 // True if there is a warning for this symbol.
670 bool has_warning_
: 1;
671 // True if we are using a COPY reloc for this symbol, so that the
672 // real definition lives in a dynamic object.
673 bool is_copied_from_dynobj_
: 1;
674 // True if the static value should be written to the GOT even
675 // when the final value is subject to dynamic relocation.
676 bool needs_value_in_got_
: 1;
679 // The parts of a symbol which are size specific. Using a template
680 // derived class like this helps us use less space on a 32-bit system.
683 class Sized_symbol
: public Symbol
686 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Value_type
;
687 typedef typename
elfcpp::Elf_types
<size
>::Elf_WXword Size_type
;
692 // Initialize fields from an ELF symbol in OBJECT.
693 template<bool big_endian
>
695 init(const char *name
, const char* version
, Object
* object
,
696 const elfcpp::Sym
<size
, big_endian
>&);
698 // Initialize fields for an Output_data.
700 init(const char* name
, Output_data
*, Value_type value
, Size_type symsize
,
701 elfcpp::STT
, elfcpp::STB
, elfcpp::STV
, unsigned char nonvis
,
702 bool offset_is_from_end
);
704 // Initialize fields for an Output_segment.
706 init(const char* name
, Output_segment
*, Value_type value
, Size_type symsize
,
707 elfcpp::STT
, elfcpp::STB
, elfcpp::STV
, unsigned char nonvis
,
708 Segment_offset_base offset_base
);
710 // Initialize fields for a constant.
712 init(const char* name
, Value_type value
, Size_type symsize
,
713 elfcpp::STT
, elfcpp::STB
, elfcpp::STV
, unsigned char nonvis
);
715 // Override existing symbol.
716 template<bool big_endian
>
718 override(const elfcpp::Sym
<size
, big_endian
>&, Object
* object
,
719 const char* version
);
721 // Override existing symbol with a special symbol.
723 override_with_special(const Sized_symbol
<size
>*);
725 // Return the symbol's value.
728 { return this->value_
; }
730 // Return the symbol's size (we can't call this 'size' because that
731 // is a template parameter).
734 { return this->symsize_
; }
736 // Set the symbol size. This is used when resolving common symbols.
738 set_symsize(Size_type symsize
)
739 { this->symsize_
= symsize
; }
741 // Set the symbol value. This is called when we store the final
742 // values of the symbols into the symbol table.
744 set_value(Value_type value
)
745 { this->value_
= value
; }
748 Sized_symbol(const Sized_symbol
&);
749 Sized_symbol
& operator=(const Sized_symbol
&);
751 // Symbol value. Before Layout::finalize this is the offset in the
752 // input section. This is set to the final value during
759 // A struct describing a symbol defined by the linker, where the value
760 // of the symbol is defined based on an output section. This is used
761 // for symbols defined by the linker, like "_init_array_start".
763 struct Define_symbol_in_section
767 // The name of the output section with which this symbol should be
768 // associated. If there is no output section with that name, the
769 // symbol will be defined as zero.
770 const char* output_section
;
771 // The offset of the symbol within the output section. This is an
772 // offset from the start of the output section, unless start_at_end
773 // is true, in which case this is an offset from the end of the
776 // The size of the symbol.
780 // The symbol binding.
782 // The symbol visibility.
783 elfcpp::STV visibility
;
784 // The rest of the st_other field.
785 unsigned char nonvis
;
786 // If true, the value field is an offset from the end of the output
788 bool offset_is_from_end
;
789 // If true, this symbol is defined only if we see a reference to it.
793 // A struct describing a symbol defined by the linker, where the value
794 // of the symbol is defined based on a segment. This is used for
795 // symbols defined by the linker, like "_end". We describe the
796 // segment with which the symbol should be associated by its
797 // characteristics. If no segment meets these characteristics, the
798 // symbol will be defined as zero. If there is more than one segment
799 // which meets these characteristics, we will use the first one.
801 struct Define_symbol_in_segment
805 // The segment type where the symbol should be defined, typically
807 elfcpp::PT segment_type
;
808 // Bitmask of segment flags which must be set.
809 elfcpp::PF segment_flags_set
;
810 // Bitmask of segment flags which must be clear.
811 elfcpp::PF segment_flags_clear
;
812 // The offset of the symbol within the segment. The offset is
813 // calculated from the position set by offset_base.
815 // The size of the symbol.
819 // The symbol binding.
821 // The symbol visibility.
822 elfcpp::STV visibility
;
823 // The rest of the st_other field.
824 unsigned char nonvis
;
825 // The base from which we compute the offset.
826 Symbol::Segment_offset_base offset_base
;
827 // If true, this symbol is defined only if we see a reference to it.
831 // This class manages warnings. Warnings are a GNU extension. When
832 // we see a section named .gnu.warning.SYM in an object file, and if
833 // we wind using the definition of SYM from that object file, then we
834 // will issue a warning for any relocation against SYM from a
835 // different object file. The text of the warning is the contents of
836 // the section. This is not precisely the definition used by the old
837 // GNU linker; the old GNU linker treated an occurrence of
838 // .gnu.warning.SYM as defining a warning symbol. A warning symbol
839 // would trigger a warning on any reference. However, it was
840 // inconsistent in that a warning in a dynamic object only triggered
841 // if there was no definition in a regular object. This linker is
842 // different in that we only issue a warning if we use the symbol
843 // definition from the same object file as the warning section.
852 // Add a warning for symbol NAME in section SHNDX in object OBJ.
854 add_warning(Symbol_table
* symtab
, const char* name
, Object
* obj
,
857 // For each symbol for which we should give a warning, make a note
860 note_warnings(Symbol_table
* symtab
);
862 // Issue a warning for a reference to SYM at RELINFO's location.
863 template<int size
, bool big_endian
>
865 issue_warning(const Symbol
* sym
, const Relocate_info
<size
, big_endian
>*,
866 size_t relnum
, off_t reloffset
) const;
869 Warnings(const Warnings
&);
870 Warnings
& operator=(const Warnings
&);
872 // What we need to know to get the warning text.
873 struct Warning_location
875 // The object the warning is in.
877 // The index of the warning section.
879 // The warning text if we have already loaded it.
883 : object(NULL
), shndx(0), text()
887 set(Object
* o
, unsigned int s
)
894 set_text(const char* t
, off_t l
)
895 { this->text
.assign(t
, l
); }
898 // A mapping from warning symbol names (canonicalized in
899 // Symbol_table's namepool_ field) to warning information.
900 typedef Unordered_map
<const char*, Warning_location
> Warning_table
;
902 Warning_table warnings_
;
905 // The main linker symbol table.
914 // Add COUNT external symbols from the relocatable object RELOBJ to
915 // the symbol table. SYMS is the symbols, SYM_NAMES is their names,
916 // SYM_NAME_SIZE is the size of SYM_NAMES. This sets SYMPOINTERS to
917 // point to the symbols in the symbol table.
918 template<int size
, bool big_endian
>
920 add_from_relobj(Sized_relobj
<size
, big_endian
>* relobj
,
921 const unsigned char* syms
, size_t count
,
922 const char* sym_names
, size_t sym_name_size
,
923 typename Sized_relobj
<size
, big_endian
>::Symbols
*);
925 // Add COUNT dynamic symbols from the dynamic object DYNOBJ to the
926 // symbol table. SYMS is the symbols. SYM_NAMES is their names.
927 // SYM_NAME_SIZE is the size of SYM_NAMES. The other parameters are
928 // symbol version data.
929 template<int size
, bool big_endian
>
931 add_from_dynobj(Sized_dynobj
<size
, big_endian
>* dynobj
,
932 const unsigned char* syms
, size_t count
,
933 const char* sym_names
, size_t sym_name_size
,
934 const unsigned char* versym
, size_t versym_size
,
935 const std::vector
<const char*>*);
937 // Define a special symbol based on an Output_data. It is a
938 // multiple definition error if this symbol is already defined.
940 define_in_output_data(const Target
*, const char* name
, const char* version
,
941 Output_data
*, uint64_t value
, uint64_t symsize
,
942 elfcpp::STT type
, elfcpp::STB binding
,
943 elfcpp::STV visibility
, unsigned char nonvis
,
944 bool offset_is_from_end
, bool only_if_ref
);
946 // Define a special symbol based on an Output_segment. It is a
947 // multiple definition error if this symbol is already defined.
949 define_in_output_segment(const Target
*, const char* name
,
950 const char* version
, Output_segment
*,
951 uint64_t value
, uint64_t symsize
,
952 elfcpp::STT type
, elfcpp::STB binding
,
953 elfcpp::STV visibility
, unsigned char nonvis
,
954 Symbol::Segment_offset_base
, bool only_if_ref
);
956 // Define a special symbol with a constant value. It is a multiple
957 // definition error if this symbol is already defined.
959 define_as_constant(const Target
*, const char* name
, const char* version
,
960 uint64_t value
, uint64_t symsize
, elfcpp::STT type
,
961 elfcpp::STB binding
, elfcpp::STV visibility
,
962 unsigned char nonvis
, bool only_if_ref
);
964 // Define a set of symbols in output sections.
966 define_symbols(const Layout
*, const Target
*, int count
,
967 const Define_symbol_in_section
*);
969 // Define a set of symbols in output segments.
971 define_symbols(const Layout
*, const Target
*, int count
,
972 const Define_symbol_in_segment
*);
974 // Define SYM using a COPY reloc. POSD is the Output_data where the
975 // symbol should be defined--typically a .dyn.bss section. VALUE is
976 // the offset within POSD.
979 define_with_copy_reloc(const Target
*, Sized_symbol
<size
>* sym
,
980 Output_data
* posd
, uint64_t value
);
984 lookup(const char*, const char* version
= NULL
) const;
986 // Return the real symbol associated with the forwarder symbol FROM.
988 resolve_forwards(const Symbol
* from
) const;
990 // Return the sized version of a symbol in this table.
993 get_sized_symbol(Symbol
* ACCEPT_SIZE
) const;
996 const Sized_symbol
<size
>*
997 get_sized_symbol(const Symbol
* ACCEPT_SIZE
) const;
999 // Return the count of undefined symbols seen.
1001 saw_undefined() const
1002 { return this->saw_undefined_
; }
1004 // Allocate the common symbols
1006 allocate_commons(const General_options
&, Layout
*);
1008 // Add a warning for symbol NAME in section SHNDX in object OBJ.
1010 add_warning(const char* name
, Object
* obj
, unsigned int shndx
)
1011 { this->warnings_
.add_warning(this, name
, obj
, shndx
); }
1013 // Canonicalize a symbol name for use in the hash table.
1015 canonicalize_name(const char* name
)
1016 { return this->namepool_
.add(name
, true, NULL
); }
1018 // Possibly issue a warning for a reference to SYM at LOCATION which
1020 template<int size
, bool big_endian
>
1022 issue_warning(const Symbol
* sym
,
1023 const Relocate_info
<size
, big_endian
>* relinfo
,
1024 size_t relnum
, off_t reloffset
) const
1025 { this->warnings_
.issue_warning(sym
, relinfo
, relnum
, reloffset
); }
1027 // Check candidate_odr_violations_ to find symbols with the same name
1028 // but apparently different definitions (different source-file/line-no).
1030 detect_odr_violations() const;
1032 // SYM is defined using a COPY reloc. Return the dynamic object
1033 // where the original definition was found.
1035 get_copy_source(const Symbol
* sym
) const;
1037 // Set the dynamic symbol indexes. INDEX is the index of the first
1038 // global dynamic symbol. Pointers to the symbols are stored into
1039 // the vector. The names are stored into the Stringpool. This
1040 // returns an updated dynamic symbol index.
1042 set_dynsym_indexes(const Target
*, unsigned int index
,
1043 std::vector
<Symbol
*>*, Stringpool
*, Versions
*);
1045 // Finalize the symbol table after we have set the final addresses
1046 // of all the input sections. This sets the final symbol indexes,
1047 // values and adds the names to *POOL. INDEX is the index of the
1048 // first global symbol. OFF is the file offset of the global symbol
1049 // table, DYNOFF is the offset of the globals in the dynamic symbol
1050 // table, DYN_GLOBAL_INDEX is the index of the first global dynamic
1051 // symbol, and DYNCOUNT is the number of global dynamic symbols.
1052 // This records the parameters, and returns the new file offset.
1054 finalize(unsigned int index
, off_t off
, off_t dynoff
,
1055 size_t dyn_global_index
, size_t dyncount
, Stringpool
* pool
);
1057 // Write out the global symbols.
1059 write_globals(const Input_objects
*, const Stringpool
*, const Stringpool
*,
1060 Output_file
*) const;
1062 // Write out a section symbol. Return the updated offset.
1064 write_section_symbol(const Output_section
*, Output_file
*, off_t
) const;
1067 Symbol_table(const Symbol_table
&);
1068 Symbol_table
& operator=(const Symbol_table
&);
1070 // Make FROM a forwarder symbol to TO.
1072 make_forwarder(Symbol
* from
, Symbol
* to
);
1075 template<int size
, bool big_endian
>
1077 add_from_object(Object
*, const char *name
, Stringpool::Key name_key
,
1078 const char *version
, Stringpool::Key version_key
,
1079 bool def
, const elfcpp::Sym
<size
, big_endian
>& sym
,
1080 const elfcpp::Sym
<size
, big_endian
>& orig_sym
);
1083 template<int size
, bool big_endian
>
1085 resolve(Sized_symbol
<size
>* to
,
1086 const elfcpp::Sym
<size
, big_endian
>& sym
,
1087 const elfcpp::Sym
<size
, big_endian
>& orig_sym
,
1088 Object
*, const char* version
);
1090 template<int size
, bool big_endian
>
1092 resolve(Sized_symbol
<size
>* to
, const Sized_symbol
<size
>* from
,
1093 const char* version ACCEPT_SIZE_ENDIAN
);
1095 // Whether we should override a symbol, based on flags in
1098 should_override(const Symbol
*, unsigned int, Object
*, bool*);
1100 // Override a symbol.
1101 template<int size
, bool big_endian
>
1103 override(Sized_symbol
<size
>* tosym
,
1104 const elfcpp::Sym
<size
, big_endian
>& fromsym
,
1105 Object
* object
, const char* version
);
1107 // Whether we should override a symbol with a special symbol which
1108 // is automatically defined by the linker.
1110 should_override_with_special(const Symbol
*);
1112 // Override a symbol with a special symbol.
1115 override_with_special(Sized_symbol
<size
>* tosym
,
1116 const Sized_symbol
<size
>* fromsym
);
1118 // Record all weak alias sets for a dynamic object.
1121 record_weak_aliases(std::vector
<Sized_symbol
<size
>*>*);
1123 // Define a special symbol.
1124 template<int size
, bool big_endian
>
1126 define_special_symbol(const Target
* target
, const char** pname
,
1127 const char** pversion
, bool only_if_ref
,
1128 Sized_symbol
<size
>** poldsym ACCEPT_SIZE_ENDIAN
);
1130 // Define a symbol in an Output_data, sized version.
1133 do_define_in_output_data(const Target
*, const char* name
,
1134 const char* version
, Output_data
*,
1135 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1136 typename
elfcpp::Elf_types
<size
>::Elf_WXword ssize
,
1137 elfcpp::STT type
, elfcpp::STB binding
,
1138 elfcpp::STV visibility
, unsigned char nonvis
,
1139 bool offset_is_from_end
, bool only_if_ref
);
1141 // Define a symbol in an Output_segment, sized version.
1144 do_define_in_output_segment(
1145 const Target
*, const char* name
, const char* version
, Output_segment
* os
,
1146 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1147 typename
elfcpp::Elf_types
<size
>::Elf_WXword ssize
,
1148 elfcpp::STT type
, elfcpp::STB binding
,
1149 elfcpp::STV visibility
, unsigned char nonvis
,
1150 Symbol::Segment_offset_base offset_base
, bool only_if_ref
);
1152 // Define a symbol as a constant, sized version.
1155 do_define_as_constant(
1156 const Target
*, const char* name
, const char* version
,
1157 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1158 typename
elfcpp::Elf_types
<size
>::Elf_WXword ssize
,
1159 elfcpp::STT type
, elfcpp::STB binding
,
1160 elfcpp::STV visibility
, unsigned char nonvis
,
1163 // Allocate the common symbols, sized version.
1166 do_allocate_commons(const General_options
&, Layout
*);
1168 // Implement detect_odr_violations.
1169 template<int size
, bool big_endian
>
1171 sized_detect_odr_violations() const;
1173 // Finalize symbols specialized for size.
1176 sized_finalize(unsigned int, off_t
, Stringpool
*);
1178 // Write globals specialized for size and endianness.
1179 template<int size
, bool big_endian
>
1181 sized_write_globals(const Input_objects
*, const Stringpool
*,
1182 const Stringpool
*, Output_file
*) const;
1184 // Write out a symbol to P.
1185 template<int size
, bool big_endian
>
1187 sized_write_symbol(Sized_symbol
<size
>*,
1188 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1190 const Stringpool
*, unsigned char* p
1191 ACCEPT_SIZE_ENDIAN
) const;
1193 // Possibly warn about an undefined symbol from a dynamic object.
1195 warn_about_undefined_dynobj_symbol(const Input_objects
*, Symbol
*) const;
1197 // Write out a section symbol, specialized for size and endianness.
1198 template<int size
, bool big_endian
>
1200 sized_write_section_symbol(const Output_section
*, Output_file
*, off_t
) const;
1202 // The type of the symbol hash table.
1204 typedef std::pair
<Stringpool::Key
, Stringpool::Key
> Symbol_table_key
;
1206 struct Symbol_table_hash
1209 operator()(const Symbol_table_key
&) const;
1212 struct Symbol_table_eq
1215 operator()(const Symbol_table_key
&, const Symbol_table_key
&) const;
1218 typedef Unordered_map
<Symbol_table_key
, Symbol
*, Symbol_table_hash
,
1219 Symbol_table_eq
> Symbol_table_type
;
1221 // The type of the list of common symbols.
1222 typedef std::vector
<Symbol
*> Commons_type
;
1224 // A map from symbols with COPY relocs to the dynamic objects where
1225 // they are defined.
1226 typedef Unordered_map
<const Symbol
*, Dynobj
*> Copied_symbol_dynobjs
;
1228 // A map from symbol name (as a pointer into the namepool) to all
1229 // the locations the symbols is (weakly) defined (and certain other
1230 // conditions are met). This map will be used later to detect
1231 // possible One Definition Rule (ODR) violations.
1232 struct Symbol_location
1234 Object
* object
; // Object where the symbol is defined.
1235 unsigned int shndx
; // Section-in-object where the symbol is defined.
1236 off_t offset
; // Offset-in-section where the symbol is defined.
1237 bool operator==(const Symbol_location
& that
) const
1239 return (this->object
== that
.object
1240 && this->shndx
== that
.shndx
1241 && this->offset
== that
.offset
);
1245 struct Symbol_location_hash
1247 size_t operator()(const Symbol_location
& loc
) const
1248 { return reinterpret_cast<uintptr_t>(loc
.object
) ^ loc
.offset
^ loc
.shndx
; }
1251 typedef Unordered_map
<const char*,
1252 Unordered_set
<Symbol_location
, Symbol_location_hash
> >
1255 // We increment this every time we see a new undefined symbol, for
1256 // use in archive groups.
1258 // The index of the first global symbol in the output file.
1259 unsigned int first_global_index_
;
1260 // The file offset within the output symtab section where we should
1263 // The number of global symbols we want to write out.
1264 size_t output_count_
;
1265 // The file offset of the global dynamic symbols, or 0 if none.
1266 off_t dynamic_offset_
;
1267 // The index of the first global dynamic symbol.
1268 unsigned int first_dynamic_global_index_
;
1269 // The number of global dynamic symbols, or 0 if none.
1270 off_t dynamic_count_
;
1271 // The symbol hash table.
1272 Symbol_table_type table_
;
1273 // A pool of symbol names. This is used for all global symbols.
1274 // Entries in the hash table point into this pool.
1275 Stringpool namepool_
;
1276 // Forwarding symbols.
1277 Unordered_map
<const Symbol
*, Symbol
*> forwarders_
;
1278 // Weak aliases. A symbol in this list points to the next alias.
1279 // The aliases point to each other in a circular list.
1280 Unordered_map
<Symbol
*, Symbol
*> weak_aliases_
;
1281 // We don't expect there to be very many common symbols, so we keep
1282 // a list of them. When we find a common symbol we add it to this
1283 // list. It is possible that by the time we process the list the
1284 // symbol is no longer a common symbol. It may also have become a
1286 Commons_type commons_
;
1287 // Manage symbol warnings.
1289 // Manage potential One Definition Rule (ODR) violations.
1290 Odr_map candidate_odr_violations_
;
1292 // When we emit a COPY reloc for a symbol, we define it in an
1293 // Output_data. When it's time to emit version information for it,
1294 // we need to know the dynamic object in which we found the original
1295 // definition. This maps symbols with COPY relocs to the dynamic
1296 // object where they were defined.
1297 Copied_symbol_dynobjs copied_symbol_dynobjs_
;
1300 // We inline get_sized_symbol for efficiency.
1304 Symbol_table::get_sized_symbol(Symbol
* sym ACCEPT_SIZE
) const
1306 gold_assert(size
== parameters
->get_size());
1307 return static_cast<Sized_symbol
<size
>*>(sym
);
1311 const Sized_symbol
<size
>*
1312 Symbol_table::get_sized_symbol(const Symbol
* sym ACCEPT_SIZE
) const
1314 gold_assert(size
== parameters
->get_size());
1315 return static_cast<const Sized_symbol
<size
>*>(sym
);
1318 } // End namespace gold.
1320 #endif // !defined(GOLD_SYMTAB_H)