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
>
55 // The base class of an entry in the symbol table. The symbol table
56 // can have a lot of entries, so we don't want this class to big.
57 // Size dependent fields can be found in the template class
58 // Sized_symbol. Targets may support their own derived classes.
63 // Because we want the class to be small, we don't use any virtual
64 // functions. But because symbols can be defined in different
65 // places, we need to classify them. This enum is the different
66 // sources of symbols we support.
69 // Symbol defined in a relocatable or dynamic input file--this is
70 // the most common case.
72 // Symbol defined in an Output_data, a special section created by
75 // Symbol defined in an Output_segment, with no associated
78 // Symbol value is constant.
82 // When the source is IN_OUTPUT_SEGMENT, we need to describe what
84 enum Segment_offset_base
86 // From the start of the segment.
88 // From the end of the segment.
90 // From the filesz of the segment--i.e., after the loaded bytes
91 // but before the bytes which are allocated but zeroed.
95 // Return the symbol name.
98 { return this->name_
; }
100 // Return the symbol version. This will return NULL for an
101 // unversioned symbol.
104 { return this->version_
; }
106 // Return the symbol source.
109 { return this->source_
; }
111 // Return the object with which this symbol is associated.
115 gold_assert(this->source_
== FROM_OBJECT
);
116 return this->u_
.from_object
.object
;
119 // Return the index of the section in the input relocatable or
120 // dynamic object file.
124 gold_assert(this->source_
== FROM_OBJECT
);
125 return this->u_
.from_object
.shndx
;
128 // Return the output data section with which this symbol is
129 // associated, if the symbol was specially defined with respect to
130 // an output data section.
134 gold_assert(this->source_
== IN_OUTPUT_DATA
);
135 return this->u_
.in_output_data
.output_data
;
138 // If this symbol was defined with respect to an output data
139 // section, return whether the value is an offset from end.
141 offset_is_from_end() const
143 gold_assert(this->source_
== IN_OUTPUT_DATA
);
144 return this->u_
.in_output_data
.offset_is_from_end
;
147 // Return the output segment with which this symbol is associated,
148 // if the symbol was specially defined with respect to an output
151 output_segment() const
153 gold_assert(this->source_
== IN_OUTPUT_SEGMENT
);
154 return this->u_
.in_output_segment
.output_segment
;
157 // If this symbol was defined with respect to an output segment,
158 // return the offset base.
162 gold_assert(this->source_
== IN_OUTPUT_SEGMENT
);
163 return this->u_
.in_output_segment
.offset_base
;
166 // Return the symbol binding.
169 { return this->binding_
; }
171 // Return the symbol type.
174 { return this->type_
; }
176 // Return the symbol visibility.
179 { return this->visibility_
; }
181 // Return the non-visibility part of the st_other field.
184 { return this->nonvis_
; }
186 // Return whether this symbol is a forwarder. This will never be
187 // true of a symbol found in the hash table, but may be true of
188 // symbol pointers attached to object files.
191 { return this->is_forwarder_
; }
193 // Mark this symbol as a forwarder.
196 { this->is_forwarder_
= true; }
198 // Return whether this symbol has an alias in the weak aliases table
202 { return this->has_alias_
; }
204 // Mark this symbol as having an alias.
207 { this->has_alias_
= true; }
209 // Return whether this symbol needs an entry in the dynamic symbol
212 needs_dynsym_entry() const
214 return (this->needs_dynsym_entry_
215 || (this->in_reg() && this->in_dyn()));
218 // Mark this symbol as needing an entry in the dynamic symbol table.
220 set_needs_dynsym_entry()
221 { this->needs_dynsym_entry_
= true; }
223 // Return whether this symbol should be added to the dynamic symbol
226 should_add_dynsym_entry() const;
228 // Return whether this symbol has been seen in a regular object.
231 { return this->in_reg_
; }
233 // Mark this symbol as having been seen in a regular object.
236 { this->in_reg_
= true; }
238 // Return whether this symbol has been seen in a dynamic object.
241 { return this->in_dyn_
; }
243 // Mark this symbol as having been seen in a dynamic object.
246 { this->in_dyn_
= true; }
248 // Return the index of this symbol in the output file symbol table.
249 // A value of -1U means that this symbol is not going into the
250 // output file. This starts out as zero, and is set to a non-zero
251 // value by Symbol_table::finalize. It is an error to ask for the
252 // symbol table index before it has been set.
256 gold_assert(this->symtab_index_
!= 0);
257 return this->symtab_index_
;
260 // Set the index of the symbol in the output file symbol table.
262 set_symtab_index(unsigned int index
)
264 gold_assert(index
!= 0);
265 this->symtab_index_
= index
;
268 // Return whether this symbol already has an index in the output
269 // file symbol table.
271 has_symtab_index() const
272 { return this->symtab_index_
!= 0; }
274 // Return the index of this symbol in the dynamic symbol table. A
275 // value of -1U means that this symbol is not going into the dynamic
276 // symbol table. This starts out as zero, and is set to a non-zero
277 // during Layout::finalize. It is an error to ask for the dynamic
278 // symbol table index before it has been set.
282 gold_assert(this->dynsym_index_
!= 0);
283 return this->dynsym_index_
;
286 // Set the index of the symbol in the dynamic symbol table.
288 set_dynsym_index(unsigned int index
)
290 gold_assert(index
!= 0);
291 this->dynsym_index_
= index
;
294 // Return whether this symbol already has an index in the dynamic
297 has_dynsym_index() const
298 { return this->dynsym_index_
!= 0; }
300 // Return whether this symbol has an entry in the GOT section.
302 has_got_offset() const
303 { return this->has_got_offset_
; }
305 // Return the offset into the GOT section of this symbol.
309 gold_assert(this->has_got_offset());
310 return this->got_offset_
;
313 // Set the GOT offset of this symbol.
315 set_got_offset(unsigned int got_offset
)
317 this->has_got_offset_
= true;
318 this->got_offset_
= got_offset
;
321 // Return whether this symbol has an entry in the PLT section.
323 has_plt_offset() const
324 { return this->has_plt_offset_
; }
326 // Return the offset into the PLT section of this symbol.
330 gold_assert(this->has_plt_offset());
331 return this->plt_offset_
;
334 // Set the PLT offset of this symbol.
336 set_plt_offset(unsigned int plt_offset
)
338 this->has_plt_offset_
= true;
339 this->plt_offset_
= plt_offset
;
342 // Return whether this dynamic symbol needs a special value in the
343 // dynamic symbol table.
345 needs_dynsym_value() const
346 { return this->needs_dynsym_value_
; }
348 // Set that this dynamic symbol needs a special value in the dynamic
351 set_needs_dynsym_value()
353 gold_assert(this->object()->is_dynamic());
354 this->needs_dynsym_value_
= true;
357 // Return true if the final value of this symbol is known at link
360 final_value_is_known() const;
362 // Return whether this is a defined symbol (not undefined or
367 return (this->source_
!= FROM_OBJECT
368 || (this->shndx() != elfcpp::SHN_UNDEF
369 && this->shndx() != elfcpp::SHN_COMMON
));
372 // Return true if this symbol is from a dynamic object.
374 is_from_dynobj() const
376 return this->source_
== FROM_OBJECT
&& this->object()->is_dynamic();
379 // Return whether this is an undefined symbol.
383 return this->source_
== FROM_OBJECT
&& this->shndx() == elfcpp::SHN_UNDEF
;
386 // Return whether this is a common symbol.
390 return (this->source_
== FROM_OBJECT
391 && (this->shndx() == elfcpp::SHN_COMMON
392 || this->type_
== elfcpp::STT_COMMON
));
395 // Return whether this symbol can be seen outside this object.
397 is_externally_visible() const
399 return (this->visibility_
== elfcpp::STV_DEFAULT
400 || this->visibility_
== elfcpp::STV_PROTECTED
);
403 // Return true if this symbol can be preempted by a definition in
404 // another link unit.
406 is_preemptible() const
408 // It doesn't make sense to ask whether a symbol defined in
409 // another object is preemptible.
410 gold_assert(!this->is_from_dynobj());
412 return (this->visibility_
!= elfcpp::STV_INTERNAL
413 && this->visibility_
!= elfcpp::STV_HIDDEN
414 && this->visibility_
!= elfcpp::STV_PROTECTED
415 && parameters
->output_is_shared()
416 && !parameters
->symbolic());
419 // Return true if this symbol is a function that needs a PLT entry.
420 // If the symbol is defined in a dynamic object or if it is subject
421 // to pre-emption, we need to make a PLT entry.
423 needs_plt_entry() const
425 return (this->type() == elfcpp::STT_FUNC
426 && (this->is_from_dynobj() || this->is_preemptible()));
429 // Given a direct absolute or pc-relative static relocation against
430 // the global symbol, this function returns whether a dynamic relocation
434 needs_dynamic_reloc(bool is_absolute_ref
, bool is_function_call
) const
436 // An absolute reference within a position-independent output file
437 // will need a dynamic relocaion.
438 if (is_absolute_ref
&& parameters
->output_is_position_independent())
441 // A function call that can branch to a local PLT entry does not need
442 // a dynamic relocation.
443 if (is_function_call
&& this->has_plt_offset())
446 // A reference to any PLT entry in a non-position-independent executable
447 // does not need a dynamic relocation.
448 if (!parameters
->output_is_position_independent()
449 && this->has_plt_offset())
452 // A reference to a symbol defined in a dynamic object or to a
453 // symbol that is preemptible will need a dynamic relocation.
454 if (this->is_from_dynobj() || this->is_preemptible())
457 // For all other cases, return FALSE.
461 // Given a direct absolute static relocation against
462 // the global symbol, where a dynamic relocation is needed, this
463 // function returns whether a relative dynamic relocation can be used.
464 // The caller must determine separately whether the static relocation
465 // is compatible with a relative relocation.
468 can_use_relative_reloc(bool is_function_call
) const
470 // A function call that can branch to a local PLT entry can
471 // use a RELATIVE relocation.
472 if (is_function_call
&& this->has_plt_offset())
475 // A reference to a symbol defined in a dynamic object or to a
476 // symbol that is preemptible can not use a RELATIVE relocaiton.
477 if (this->is_from_dynobj() || this->is_preemptible())
480 // For all other cases, return TRUE.
484 // Return whether there should be a warning for references to this
488 { return this->has_warning_
; }
490 // Mark this symbol as having a warning.
493 { this->has_warning_
= true; }
495 // Return whether this symbol is defined by a COPY reloc from a
498 is_copied_from_dynobj() const
499 { return this->is_copied_from_dynobj_
; }
501 // Mark this symbol as defined by a COPY reloc.
503 set_is_copied_from_dynobj()
504 { this->is_copied_from_dynobj_
= true; }
506 // Mark this symbol as needing its value written to the GOT even when
507 // the value is subject to dynamic relocation (e.g., when the target
508 // uses a RELATIVE relocation for the GOT entry).
510 set_needs_value_in_got()
511 { this->needs_value_in_got_
= true; }
513 // Return whether this symbol needs its value written to the GOT even
514 // when the value is subject to dynamic relocation.
516 needs_value_in_got() const
517 { return this->needs_value_in_got_
; }
520 // Instances of this class should always be created at a specific
523 { memset(this, 0, sizeof *this); }
525 // Initialize the general fields.
527 init_fields(const char* name
, const char* version
,
528 elfcpp::STT type
, elfcpp::STB binding
,
529 elfcpp::STV visibility
, unsigned char nonvis
);
531 // Initialize fields from an ELF symbol in OBJECT.
532 template<int size
, bool big_endian
>
534 init_base(const char *name
, const char* version
, Object
* object
,
535 const elfcpp::Sym
<size
, big_endian
>&);
537 // Initialize fields for an Output_data.
539 init_base(const char* name
, Output_data
*, elfcpp::STT
, elfcpp::STB
,
540 elfcpp::STV
, unsigned char nonvis
, bool offset_is_from_end
);
542 // Initialize fields for an Output_segment.
544 init_base(const char* name
, Output_segment
* os
, elfcpp::STT type
,
545 elfcpp::STB binding
, elfcpp::STV visibility
,
546 unsigned char nonvis
, Segment_offset_base offset_base
);
548 // Initialize fields for a constant.
550 init_base(const char* name
, elfcpp::STT type
, elfcpp::STB binding
,
551 elfcpp::STV visibility
, unsigned char nonvis
);
553 // Override existing symbol.
554 template<int size
, bool big_endian
>
556 override_base(const elfcpp::Sym
<size
, big_endian
>&, Object
* object
,
557 const char* version
);
559 // Override existing symbol with a special symbol.
561 override_base_with_special(const Symbol
* from
);
564 Symbol(const Symbol
&);
565 Symbol
& operator=(const Symbol
&);
567 // Symbol name (expected to point into a Stringpool).
569 // Symbol version (expected to point into a Stringpool). This may
571 const char* version_
;
575 // This struct is used if SOURCE_ == FROM_OBJECT.
578 // Object in which symbol is defined, or in which it was first
581 // Section number in object_ in which symbol is defined.
585 // This struct is used if SOURCE_ == IN_OUTPUT_DATA.
588 // Output_data in which symbol is defined. Before
589 // Layout::finalize the symbol's value is an offset within the
591 Output_data
* output_data
;
592 // True if the offset is from the end, false if the offset is
593 // from the beginning.
594 bool offset_is_from_end
;
597 // This struct is used if SOURCE_ == IN_OUTPUT_SEGMENT.
600 // Output_segment in which the symbol is defined. Before
601 // Layout::finalize the symbol's value is an offset.
602 Output_segment
* output_segment
;
603 // The base to use for the offset before Layout::finalize.
604 Segment_offset_base offset_base
;
608 // The index of this symbol in the output file. If the symbol is
609 // not going into the output file, this value is -1U. This field
610 // starts as always holding zero. It is set to a non-zero value by
611 // Symbol_table::finalize.
612 unsigned int symtab_index_
;
614 // The index of this symbol in the dynamic symbol table. If the
615 // symbol is not going into the dynamic symbol table, this value is
616 // -1U. This field starts as always holding zero. It is set to a
617 // non-zero value during Layout::finalize.
618 unsigned int dynsym_index_
;
620 // If this symbol has an entry in the GOT section (has_got_offset_
621 // is true), this is the offset from the start of the GOT section.
622 unsigned int got_offset_
;
624 // If this symbol has an entry in the PLT section (has_plt_offset_
625 // is true), then this is the offset from the start of the PLT
627 unsigned int plt_offset_
;
630 elfcpp::STT type_
: 4;
632 elfcpp::STB binding_
: 4;
633 // Symbol visibility.
634 elfcpp::STV visibility_
: 2;
635 // Rest of symbol st_other field.
636 unsigned int nonvis_
: 6;
637 // The type of symbol.
639 // True if this symbol always requires special target-specific
641 bool is_target_special_
: 1;
642 // True if this is the default version of the symbol.
644 // True if this symbol really forwards to another symbol. This is
645 // used when we discover after the fact that two different entries
646 // in the hash table really refer to the same symbol. This will
647 // never be set for a symbol found in the hash table, but may be set
648 // for a symbol found in the list of symbols attached to an Object.
649 // It forwards to the symbol found in the forwarders_ map of
651 bool is_forwarder_
: 1;
652 // True if the symbol has an alias in the weak_aliases table in
655 // True if this symbol needs to be in the dynamic symbol table.
656 bool needs_dynsym_entry_
: 1;
657 // True if we've seen this symbol in a regular object.
659 // True if we've seen this symbol in a dynamic object.
661 // True if the symbol has an entry in the GOT section.
662 bool has_got_offset_
: 1;
663 // True if the symbol has an entry in the PLT section.
664 bool has_plt_offset_
: 1;
665 // True if this is a dynamic symbol which needs a special value in
666 // the dynamic symbol table.
667 bool needs_dynsym_value_
: 1;
668 // True if there is a warning for this symbol.
669 bool has_warning_
: 1;
670 // True if we are using a COPY reloc for this symbol, so that the
671 // real definition lives in a dynamic object.
672 bool is_copied_from_dynobj_
: 1;
673 // True if the static value should be written to the GOT even
674 // when the final value is subject to dynamic relocation.
675 bool needs_value_in_got_
: 1;
678 // The parts of a symbol which are size specific. Using a template
679 // derived class like this helps us use less space on a 32-bit system.
682 class Sized_symbol
: public Symbol
685 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Value_type
;
686 typedef typename
elfcpp::Elf_types
<size
>::Elf_WXword Size_type
;
691 // Initialize fields from an ELF symbol in OBJECT.
692 template<bool big_endian
>
694 init(const char *name
, const char* version
, Object
* object
,
695 const elfcpp::Sym
<size
, big_endian
>&);
697 // Initialize fields for an Output_data.
699 init(const char* name
, Output_data
*, Value_type value
, Size_type symsize
,
700 elfcpp::STT
, elfcpp::STB
, elfcpp::STV
, unsigned char nonvis
,
701 bool offset_is_from_end
);
703 // Initialize fields for an Output_segment.
705 init(const char* name
, Output_segment
*, Value_type value
, Size_type symsize
,
706 elfcpp::STT
, elfcpp::STB
, elfcpp::STV
, unsigned char nonvis
,
707 Segment_offset_base offset_base
);
709 // Initialize fields for a constant.
711 init(const char* name
, Value_type value
, Size_type symsize
,
712 elfcpp::STT
, elfcpp::STB
, elfcpp::STV
, unsigned char nonvis
);
714 // Override existing symbol.
715 template<bool big_endian
>
717 override(const elfcpp::Sym
<size
, big_endian
>&, Object
* object
,
718 const char* version
);
720 // Override existing symbol with a special symbol.
722 override_with_special(const Sized_symbol
<size
>*);
724 // Return the symbol's value.
727 { return this->value_
; }
729 // Return the symbol's size (we can't call this 'size' because that
730 // is a template parameter).
733 { return this->symsize_
; }
735 // Set the symbol size. This is used when resolving common symbols.
737 set_symsize(Size_type symsize
)
738 { this->symsize_
= symsize
; }
740 // Set the symbol value. This is called when we store the final
741 // values of the symbols into the symbol table.
743 set_value(Value_type value
)
744 { this->value_
= value
; }
747 Sized_symbol(const Sized_symbol
&);
748 Sized_symbol
& operator=(const Sized_symbol
&);
750 // Symbol value. Before Layout::finalize this is the offset in the
751 // input section. This is set to the final value during
758 // A struct describing a symbol defined by the linker, where the value
759 // of the symbol is defined based on an output section. This is used
760 // for symbols defined by the linker, like "_init_array_start".
762 struct Define_symbol_in_section
766 // The name of the output section with which this symbol should be
767 // associated. If there is no output section with that name, the
768 // symbol will be defined as zero.
769 const char* output_section
;
770 // The offset of the symbol within the output section. This is an
771 // offset from the start of the output section, unless start_at_end
772 // is true, in which case this is an offset from the end of the
775 // The size of the symbol.
779 // The symbol binding.
781 // The symbol visibility.
782 elfcpp::STV visibility
;
783 // The rest of the st_other field.
784 unsigned char nonvis
;
785 // If true, the value field is an offset from the end of the output
787 bool offset_is_from_end
;
788 // If true, this symbol is defined only if we see a reference to it.
792 // A struct describing a symbol defined by the linker, where the value
793 // of the symbol is defined based on a segment. This is used for
794 // symbols defined by the linker, like "_end". We describe the
795 // segment with which the symbol should be associated by its
796 // characteristics. If no segment meets these characteristics, the
797 // symbol will be defined as zero. If there is more than one segment
798 // which meets these characteristics, we will use the first one.
800 struct Define_symbol_in_segment
804 // The segment type where the symbol should be defined, typically
806 elfcpp::PT segment_type
;
807 // Bitmask of segment flags which must be set.
808 elfcpp::PF segment_flags_set
;
809 // Bitmask of segment flags which must be clear.
810 elfcpp::PF segment_flags_clear
;
811 // The offset of the symbol within the segment. The offset is
812 // calculated from the position set by offset_base.
814 // The size of the symbol.
818 // The symbol binding.
820 // The symbol visibility.
821 elfcpp::STV visibility
;
822 // The rest of the st_other field.
823 unsigned char nonvis
;
824 // The base from which we compute the offset.
825 Symbol::Segment_offset_base offset_base
;
826 // If true, this symbol is defined only if we see a reference to it.
830 // This class manages warnings. Warnings are a GNU extension. When
831 // we see a section named .gnu.warning.SYM in an object file, and if
832 // we wind using the definition of SYM from that object file, then we
833 // will issue a warning for any relocation against SYM from a
834 // different object file. The text of the warning is the contents of
835 // the section. This is not precisely the definition used by the old
836 // GNU linker; the old GNU linker treated an occurrence of
837 // .gnu.warning.SYM as defining a warning symbol. A warning symbol
838 // would trigger a warning on any reference. However, it was
839 // inconsistent in that a warning in a dynamic object only triggered
840 // if there was no definition in a regular object. This linker is
841 // different in that we only issue a warning if we use the symbol
842 // definition from the same object file as the warning section.
851 // Add a warning for symbol NAME in section SHNDX in object OBJ.
853 add_warning(Symbol_table
* symtab
, const char* name
, Object
* obj
,
856 // For each symbol for which we should give a warning, make a note
859 note_warnings(Symbol_table
* symtab
);
861 // Issue a warning for a reference to SYM at RELINFO's location.
862 template<int size
, bool big_endian
>
864 issue_warning(const Symbol
* sym
, const Relocate_info
<size
, big_endian
>*,
865 size_t relnum
, off_t reloffset
) const;
868 Warnings(const Warnings
&);
869 Warnings
& operator=(const Warnings
&);
871 // What we need to know to get the warning text.
872 struct Warning_location
874 // The object the warning is in.
876 // The index of the warning section.
878 // The warning text if we have already loaded it.
882 : object(NULL
), shndx(0), text()
886 set(Object
* o
, unsigned int s
)
893 set_text(const char* t
, off_t l
)
894 { this->text
.assign(t
, l
); }
897 // A mapping from warning symbol names (canonicalized in
898 // Symbol_table's namepool_ field) to warning information.
899 typedef Unordered_map
<const char*, Warning_location
> Warning_table
;
901 Warning_table warnings_
;
904 // The main linker symbol table.
913 // Add COUNT external symbols from the relocatable object RELOBJ to
914 // the symbol table. SYMS is the symbols, SYM_NAMES is their names,
915 // SYM_NAME_SIZE is the size of SYM_NAMES. This sets SYMPOINTERS to
916 // point to the symbols in the symbol table.
917 template<int size
, bool big_endian
>
919 add_from_relobj(Sized_relobj
<size
, big_endian
>* relobj
,
920 const unsigned char* syms
, size_t count
,
921 const char* sym_names
, size_t sym_name_size
,
922 typename Sized_relobj
<size
, big_endian
>::Symbols
*);
924 // Add COUNT dynamic symbols from the dynamic object DYNOBJ to the
925 // symbol table. SYMS is the symbols. SYM_NAMES is their names.
926 // SYM_NAME_SIZE is the size of SYM_NAMES. The other parameters are
927 // symbol version data.
928 template<int size
, bool big_endian
>
930 add_from_dynobj(Sized_dynobj
<size
, big_endian
>* dynobj
,
931 const unsigned char* syms
, size_t count
,
932 const char* sym_names
, size_t sym_name_size
,
933 const unsigned char* versym
, size_t versym_size
,
934 const std::vector
<const char*>*);
936 // Define a special symbol based on an Output_data. It is a
937 // multiple definition error if this symbol is already defined.
939 define_in_output_data(const Target
*, const char* name
, const char* version
,
940 Output_data
*, uint64_t value
, uint64_t symsize
,
941 elfcpp::STT type
, elfcpp::STB binding
,
942 elfcpp::STV visibility
, unsigned char nonvis
,
943 bool offset_is_from_end
, bool only_if_ref
);
945 // Define a special symbol based on an Output_segment. It is a
946 // multiple definition error if this symbol is already defined.
948 define_in_output_segment(const Target
*, const char* name
,
949 const char* version
, Output_segment
*,
950 uint64_t value
, uint64_t symsize
,
951 elfcpp::STT type
, elfcpp::STB binding
,
952 elfcpp::STV visibility
, unsigned char nonvis
,
953 Symbol::Segment_offset_base
, bool only_if_ref
);
955 // Define a special symbol with a constant value. It is a multiple
956 // definition error if this symbol is already defined.
958 define_as_constant(const Target
*, const char* name
, const char* version
,
959 uint64_t value
, uint64_t symsize
, elfcpp::STT type
,
960 elfcpp::STB binding
, elfcpp::STV visibility
,
961 unsigned char nonvis
, bool only_if_ref
);
963 // Define a set of symbols in output sections.
965 define_symbols(const Layout
*, const Target
*, int count
,
966 const Define_symbol_in_section
*);
968 // Define a set of symbols in output segments.
970 define_symbols(const Layout
*, const Target
*, int count
,
971 const Define_symbol_in_segment
*);
973 // Define SYM using a COPY reloc. POSD is the Output_data where the
974 // symbol should be defined--typically a .dyn.bss section. VALUE is
975 // the offset within POSD.
978 define_with_copy_reloc(const Target
*, Sized_symbol
<size
>* sym
,
979 Output_data
* posd
, uint64_t value
);
983 lookup(const char*, const char* version
= NULL
) const;
985 // Return the real symbol associated with the forwarder symbol FROM.
987 resolve_forwards(const Symbol
* from
) const;
989 // Return the sized version of a symbol in this table.
992 get_sized_symbol(Symbol
* ACCEPT_SIZE
) const;
995 const Sized_symbol
<size
>*
996 get_sized_symbol(const Symbol
* ACCEPT_SIZE
) const;
998 // Return the count of undefined symbols seen.
1000 saw_undefined() const
1001 { return this->saw_undefined_
; }
1003 // Allocate the common symbols
1005 allocate_commons(const General_options
&, Layout
*);
1007 // Add a warning for symbol NAME in section SHNDX in object OBJ.
1009 add_warning(const char* name
, Object
* obj
, unsigned int shndx
)
1010 { this->warnings_
.add_warning(this, name
, obj
, shndx
); }
1012 // Canonicalize a symbol name for use in the hash table.
1014 canonicalize_name(const char* name
)
1015 { return this->namepool_
.add(name
, true, NULL
); }
1017 // Possibly issue a warning for a reference to SYM at LOCATION which
1019 template<int size
, bool big_endian
>
1021 issue_warning(const Symbol
* sym
,
1022 const Relocate_info
<size
, big_endian
>* relinfo
,
1023 size_t relnum
, off_t reloffset
) const
1024 { this->warnings_
.issue_warning(sym
, relinfo
, relnum
, reloffset
); }
1026 // Check candidate_odr_violations_ to find symbols with the same name
1027 // but apparently different definitions (different source-file/line-no).
1029 detect_odr_violations() const;
1031 // SYM is defined using a COPY reloc. Return the dynamic object
1032 // where the original definition was found.
1034 get_copy_source(const Symbol
* sym
) const;
1036 // Set the dynamic symbol indexes. INDEX is the index of the first
1037 // global dynamic symbol. Pointers to the symbols are stored into
1038 // the vector. The names are stored into the Stringpool. This
1039 // returns an updated dynamic symbol index.
1041 set_dynsym_indexes(const Target
*, unsigned int index
,
1042 std::vector
<Symbol
*>*, Stringpool
*, Versions
*);
1044 // Finalize the symbol table after we have set the final addresses
1045 // of all the input sections. This sets the final symbol indexes,
1046 // values and adds the names to *POOL. INDEX is the index of the
1047 // first global symbol. OFF is the file offset of the global symbol
1048 // table, DYNOFF is the offset of the globals in the dynamic symbol
1049 // table, DYN_GLOBAL_INDEX is the index of the first global dynamic
1050 // symbol, and DYNCOUNT is the number of global dynamic symbols.
1051 // This records the parameters, and returns the new file offset.
1053 finalize(unsigned int index
, off_t off
, off_t dynoff
,
1054 size_t dyn_global_index
, size_t dyncount
, Stringpool
* pool
);
1056 // Write out the global symbols.
1058 write_globals(const Target
*, const Stringpool
*, const Stringpool
*,
1059 Output_file
*) const;
1061 // Write out a section symbol. Return the updated offset.
1063 write_section_symbol(const Output_section
*, Output_file
*, off_t
) const;
1066 Symbol_table(const Symbol_table
&);
1067 Symbol_table
& operator=(const Symbol_table
&);
1069 // Make FROM a forwarder symbol to TO.
1071 make_forwarder(Symbol
* from
, Symbol
* to
);
1074 template<int size
, bool big_endian
>
1076 add_from_object(Object
*, const char *name
, Stringpool::Key name_key
,
1077 const char *version
, Stringpool::Key version_key
,
1078 bool def
, const elfcpp::Sym
<size
, big_endian
>& sym
,
1079 const elfcpp::Sym
<size
, big_endian
>& orig_sym
);
1082 template<int size
, bool big_endian
>
1084 resolve(Sized_symbol
<size
>* to
,
1085 const elfcpp::Sym
<size
, big_endian
>& sym
,
1086 const elfcpp::Sym
<size
, big_endian
>& orig_sym
,
1087 Object
*, const char* version
);
1089 template<int size
, bool big_endian
>
1091 resolve(Sized_symbol
<size
>* to
, const Sized_symbol
<size
>* from
,
1092 const char* version ACCEPT_SIZE_ENDIAN
);
1094 // Whether we should override a symbol, based on flags in
1097 should_override(const Symbol
*, unsigned int, Object
*, bool*);
1099 // Override a symbol.
1100 template<int size
, bool big_endian
>
1102 override(Sized_symbol
<size
>* tosym
,
1103 const elfcpp::Sym
<size
, big_endian
>& fromsym
,
1104 Object
* object
, const char* version
);
1106 // Whether we should override a symbol with a special symbol which
1107 // is automatically defined by the linker.
1109 should_override_with_special(const Symbol
*);
1111 // Override a symbol with a special symbol.
1114 override_with_special(Sized_symbol
<size
>* tosym
,
1115 const Sized_symbol
<size
>* fromsym
);
1117 // Record all weak alias sets for a dynamic object.
1120 record_weak_aliases(std::vector
<Sized_symbol
<size
>*>*);
1122 // Define a special symbol.
1123 template<int size
, bool big_endian
>
1125 define_special_symbol(const Target
* target
, const char** pname
,
1126 const char** pversion
, bool only_if_ref
,
1127 Sized_symbol
<size
>** poldsym ACCEPT_SIZE_ENDIAN
);
1129 // Define a symbol in an Output_data, sized version.
1132 do_define_in_output_data(const Target
*, const char* name
,
1133 const char* version
, Output_data
*,
1134 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1135 typename
elfcpp::Elf_types
<size
>::Elf_WXword ssize
,
1136 elfcpp::STT type
, elfcpp::STB binding
,
1137 elfcpp::STV visibility
, unsigned char nonvis
,
1138 bool offset_is_from_end
, bool only_if_ref
);
1140 // Define a symbol in an Output_segment, sized version.
1143 do_define_in_output_segment(
1144 const Target
*, const char* name
, const char* version
, Output_segment
* os
,
1145 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1146 typename
elfcpp::Elf_types
<size
>::Elf_WXword ssize
,
1147 elfcpp::STT type
, elfcpp::STB binding
,
1148 elfcpp::STV visibility
, unsigned char nonvis
,
1149 Symbol::Segment_offset_base offset_base
, bool only_if_ref
);
1151 // Define a symbol as a constant, sized version.
1154 do_define_as_constant(
1155 const Target
*, const char* name
, const char* version
,
1156 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1157 typename
elfcpp::Elf_types
<size
>::Elf_WXword ssize
,
1158 elfcpp::STT type
, elfcpp::STB binding
,
1159 elfcpp::STV visibility
, unsigned char nonvis
,
1162 // Allocate the common symbols, sized version.
1165 do_allocate_commons(const General_options
&, Layout
*);
1167 // Implement detect_odr_violations.
1168 template<int size
, bool big_endian
>
1170 sized_detect_odr_violations() const;
1172 // Finalize symbols specialized for size.
1175 sized_finalize(unsigned int, off_t
, Stringpool
*);
1177 // Write globals specialized for size and endianness.
1178 template<int size
, bool big_endian
>
1180 sized_write_globals(const Target
*, const Stringpool
*, const Stringpool
*,
1181 Output_file
*) const;
1183 // Write out a symbol to P.
1184 template<int size
, bool big_endian
>
1186 sized_write_symbol(Sized_symbol
<size
>*,
1187 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1189 const Stringpool
*, unsigned char* p
1190 ACCEPT_SIZE_ENDIAN
) const;
1192 // Write out a section symbol, specialized for size and endianness.
1193 template<int size
, bool big_endian
>
1195 sized_write_section_symbol(const Output_section
*, Output_file
*, off_t
) const;
1197 // The type of the symbol hash table.
1199 typedef std::pair
<Stringpool::Key
, Stringpool::Key
> Symbol_table_key
;
1201 struct Symbol_table_hash
1204 operator()(const Symbol_table_key
&) const;
1207 struct Symbol_table_eq
1210 operator()(const Symbol_table_key
&, const Symbol_table_key
&) const;
1213 typedef Unordered_map
<Symbol_table_key
, Symbol
*, Symbol_table_hash
,
1214 Symbol_table_eq
> Symbol_table_type
;
1216 // The type of the list of common symbols.
1217 typedef std::vector
<Symbol
*> Commons_type
;
1219 // A map from symbols with COPY relocs to the dynamic objects where
1220 // they are defined.
1221 typedef Unordered_map
<const Symbol
*, Dynobj
*> Copied_symbol_dynobjs
;
1223 // A map from symbol name (as a pointer into the namepool) to all
1224 // the locations the symbols is (weakly) defined (and certain other
1225 // conditions are met). This map will be used later to detect
1226 // possible One Definition Rule (ODR) violations.
1227 struct Symbol_location
1229 Object
* object
; // Object where the symbol is defined.
1230 unsigned int shndx
; // Section-in-object where the symbol is defined.
1231 off_t offset
; // Offset-in-section where the symbol is defined.
1232 bool operator==(const Symbol_location
& that
) const
1234 return (this->object
== that
.object
1235 && this->shndx
== that
.shndx
1236 && this->offset
== that
.offset
);
1240 struct Symbol_location_hash
1242 size_t operator()(const Symbol_location
& loc
) const
1243 { return reinterpret_cast<uintptr_t>(loc
.object
) ^ loc
.offset
^ loc
.shndx
; }
1246 typedef Unordered_map
<const char*,
1247 Unordered_set
<Symbol_location
, Symbol_location_hash
> >
1250 // We increment this every time we see a new undefined symbol, for
1251 // use in archive groups.
1253 // The index of the first global symbol in the output file.
1254 unsigned int first_global_index_
;
1255 // The file offset within the output symtab section where we should
1258 // The number of global symbols we want to write out.
1259 size_t output_count_
;
1260 // The file offset of the global dynamic symbols, or 0 if none.
1261 off_t dynamic_offset_
;
1262 // The index of the first global dynamic symbol.
1263 unsigned int first_dynamic_global_index_
;
1264 // The number of global dynamic symbols, or 0 if none.
1265 off_t dynamic_count_
;
1266 // The symbol hash table.
1267 Symbol_table_type table_
;
1268 // A pool of symbol names. This is used for all global symbols.
1269 // Entries in the hash table point into this pool.
1270 Stringpool namepool_
;
1271 // Forwarding symbols.
1272 Unordered_map
<const Symbol
*, Symbol
*> forwarders_
;
1273 // Weak aliases. A symbol in this list points to the next alias.
1274 // The aliases point to each other in a circular list.
1275 Unordered_map
<Symbol
*, Symbol
*> weak_aliases_
;
1276 // We don't expect there to be very many common symbols, so we keep
1277 // a list of them. When we find a common symbol we add it to this
1278 // list. It is possible that by the time we process the list the
1279 // symbol is no longer a common symbol. It may also have become a
1281 Commons_type commons_
;
1282 // Manage symbol warnings.
1284 // Manage potential One Definition Rule (ODR) violations.
1285 Odr_map candidate_odr_violations_
;
1287 // When we emit a COPY reloc for a symbol, we define it in an
1288 // Output_data. When it's time to emit version information for it,
1289 // we need to know the dynamic object in which we found the original
1290 // definition. This maps symbols with COPY relocs to the dynamic
1291 // object where they were defined.
1292 Copied_symbol_dynobjs copied_symbol_dynobjs_
;
1295 // We inline get_sized_symbol for efficiency.
1299 Symbol_table::get_sized_symbol(Symbol
* sym ACCEPT_SIZE
) const
1301 gold_assert(size
== parameters
->get_size());
1302 return static_cast<Sized_symbol
<size
>*>(sym
);
1306 const Sized_symbol
<size
>*
1307 Symbol_table::get_sized_symbol(const Symbol
* sym ACCEPT_SIZE
) const
1309 gold_assert(size
== parameters
->get_size());
1310 return static_cast<const Sized_symbol
<size
>*>(sym
);
1313 } // End namespace gold.
1315 #endif // !defined(GOLD_SYMTAB_H)