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 (ANSI) demangled version of the name, if
102 // parameters.demangle() is true. Otherwise, return the name. This
103 // is intended to be used only for logging errors, so it's not
106 demangled_name() const;
108 // Return the symbol version. This will return NULL for an
109 // unversioned symbol.
112 { return this->version_; }
114 // Return the symbol source.
117 { return this->source_; }
119 // Return the object with which this symbol is associated.
123 gold_assert(this->source_ == FROM_OBJECT);
124 return this->u_.from_object.object;
127 // Return the index of the section in the input relocatable or
128 // dynamic object file.
132 gold_assert(this->source_ == FROM_OBJECT);
133 return this->u_.from_object.shndx;
136 // Return the output data section with which this symbol is
137 // associated, if the symbol was specially defined with respect to
138 // an output data section.
142 gold_assert(this->source_ == IN_OUTPUT_DATA);
143 return this->u_.in_output_data.output_data;
146 // If this symbol was defined with respect to an output data
147 // section, return whether the value is an offset from end.
149 offset_is_from_end() const
151 gold_assert(this->source_ == IN_OUTPUT_DATA);
152 return this->u_.in_output_data.offset_is_from_end;
155 // Return the output segment with which this symbol is associated,
156 // if the symbol was specially defined with respect to an output
159 output_segment() const
161 gold_assert(this->source_ == IN_OUTPUT_SEGMENT);
162 return this->u_.in_output_segment.output_segment;
165 // If this symbol was defined with respect to an output segment,
166 // return the offset base.
170 gold_assert(this->source_ == IN_OUTPUT_SEGMENT);
171 return this->u_.in_output_segment.offset_base;
174 // Return the symbol binding.
177 { return this->binding_; }
179 // Return the symbol type.
182 { return this->type_; }
184 // Return the symbol visibility.
187 { return this->visibility_; }
189 // Return the non-visibility part of the st_other field.
192 { return this->nonvis_; }
194 // Return whether this symbol is a forwarder. This will never be
195 // true of a symbol found in the hash table, but may be true of
196 // symbol pointers attached to object files.
199 { return this->is_forwarder_; }
201 // Mark this symbol as a forwarder.
204 { this->is_forwarder_ = true; }
206 // Return whether this symbol has an alias in the weak aliases table
210 { return this->has_alias_; }
212 // Mark this symbol as having an alias.
215 { this->has_alias_ = true; }
217 // Return whether this symbol needs an entry in the dynamic symbol
220 needs_dynsym_entry() const
222 return (this->needs_dynsym_entry_
223 || (this->in_reg() && this->in_dyn()));
226 // Mark this symbol as needing an entry in the dynamic symbol table.
228 set_needs_dynsym_entry()
229 { this->needs_dynsym_entry_ = true; }
231 // Return whether this symbol should be added to the dynamic symbol
234 should_add_dynsym_entry() const;
236 // Return whether this symbol has been seen in a regular object.
239 { return this->in_reg_; }
241 // Mark this symbol as having been seen in a regular object.
244 { this->in_reg_ = true; }
246 // Return whether this symbol has been seen in a dynamic object.
249 { return this->in_dyn_; }
251 // Mark this symbol as having been seen in a dynamic object.
254 { this->in_dyn_ = true; }
256 // Return the index of this symbol in the output file symbol table.
257 // A value of -1U means that this symbol is not going into the
258 // output file. This starts out as zero, and is set to a non-zero
259 // value by Symbol_table::finalize. It is an error to ask for the
260 // symbol table index before it has been set.
264 gold_assert(this->symtab_index_ != 0);
265 return this->symtab_index_;
268 // Set the index of the symbol in the output file symbol table.
270 set_symtab_index(unsigned int index)
272 gold_assert(index != 0);
273 this->symtab_index_ = index;
276 // Return whether this symbol already has an index in the output
277 // file symbol table.
279 has_symtab_index() const
280 { return this->symtab_index_ != 0; }
282 // Return the index of this symbol in the dynamic symbol table. A
283 // value of -1U means that this symbol is not going into the dynamic
284 // symbol table. This starts out as zero, and is set to a non-zero
285 // during Layout::finalize. It is an error to ask for the dynamic
286 // symbol table index before it has been set.
290 gold_assert(this->dynsym_index_ != 0);
291 return this->dynsym_index_;
294 // Set the index of the symbol in the dynamic symbol table.
296 set_dynsym_index(unsigned int index)
298 gold_assert(index != 0);
299 this->dynsym_index_ = index;
302 // Return whether this symbol already has an index in the dynamic
305 has_dynsym_index() const
306 { return this->dynsym_index_ != 0; }
308 // Return whether this symbol has an entry in the GOT section.
309 // For a TLS symbol, this GOT entry will hold its tp-relative offset.
311 has_got_offset() const
312 { return this->has_got_offset_; }
314 // Return the offset into the GOT section of this symbol.
318 gold_assert(this->has_got_offset());
319 return this->got_offset_;
322 // Set the GOT offset of this symbol.
324 set_got_offset(unsigned int got_offset)
326 this->has_got_offset_ = true;
327 this->got_offset_ = got_offset;
330 // Return whether this TLS symbol has an entry in the GOT section for
331 // its module index or, if NEED_PAIR is true, has a pair of entries
332 // for its module index and dtv-relative offset.
334 has_tls_got_offset(bool need_pair) const
336 return (this->has_tls_mod_got_offset_
337 && (!need_pair || this->has_tls_pair_got_offset_));
340 // Return the offset into the GOT section for this symbol's TLS module
341 // index or, if NEED_PAIR is true, for the pair of entries for the
342 // module index and dtv-relative offset.
344 tls_got_offset(bool need_pair) const
346 gold_assert(this->has_tls_got_offset(need_pair));
347 return this->tls_mod_got_offset_;
350 // Set the GOT offset of this symbol.
352 set_tls_got_offset(unsigned int got_offset, bool have_pair)
354 this->has_tls_mod_got_offset_ = true;
355 this->has_tls_pair_got_offset_ = have_pair;
356 this->tls_mod_got_offset_ = got_offset;
359 // Return whether this symbol has an entry in the PLT section.
361 has_plt_offset() const
362 { return this->has_plt_offset_; }
364 // Return the offset into the PLT section of this symbol.
368 gold_assert(this->has_plt_offset());
369 return this->plt_offset_;
372 // Set the PLT offset of this symbol.
374 set_plt_offset(unsigned int plt_offset)
376 this->has_plt_offset_ = true;
377 this->plt_offset_ = plt_offset;
380 // Return whether this dynamic symbol needs a special value in the
381 // dynamic symbol table.
383 needs_dynsym_value() const
384 { return this->needs_dynsym_value_; }
386 // Set that this dynamic symbol needs a special value in the dynamic
389 set_needs_dynsym_value()
391 gold_assert(this->object()->is_dynamic());
392 this->needs_dynsym_value_ = true;
395 // Return true if the final value of this symbol is known at link
398 final_value_is_known() const;
400 // Return whether this is a defined symbol (not undefined or
405 return (this->source_ != FROM_OBJECT
406 || (this->shndx() != elfcpp::SHN_UNDEF
407 && this->shndx() != elfcpp::SHN_COMMON));
410 // Return true if this symbol is from a dynamic object.
412 is_from_dynobj() const
414 return this->source_ == FROM_OBJECT && this->object()->is_dynamic();
417 // Return whether this is an undefined symbol.
421 return this->source_ == FROM_OBJECT && this->shndx() == elfcpp::SHN_UNDEF;
424 // Return whether this is a common symbol.
428 return (this->source_ == FROM_OBJECT
429 && (this->shndx() == elfcpp::SHN_COMMON
430 || this->type_ == elfcpp::STT_COMMON));
433 // Return whether this symbol can be seen outside this object.
435 is_externally_visible() const
437 return (this->visibility_ == elfcpp::STV_DEFAULT
438 || this->visibility_ == elfcpp::STV_PROTECTED);
441 // Return true if this symbol can be preempted by a definition in
442 // another link unit.
444 is_preemptible() const
446 // It doesn't make sense to ask whether a symbol defined in
447 // another object is preemptible.
448 gold_assert(!this->is_from_dynobj());
450 return (this->visibility_ != elfcpp::STV_INTERNAL
451 && this->visibility_ != elfcpp::STV_HIDDEN
452 && this->visibility_ != elfcpp::STV_PROTECTED
453 && parameters->output_is_shared()
454 && !parameters->symbolic());
457 // Return true if this symbol is a function that needs a PLT entry.
458 // If the symbol is defined in a dynamic object or if it is subject
459 // to pre-emption, we need to make a PLT entry.
461 needs_plt_entry() const
463 return (this->type() == elfcpp::STT_FUNC
464 && (this->is_from_dynobj() || this->is_preemptible()));
467 // Given a direct absolute or pc-relative static relocation against
468 // the global symbol, this function returns whether a dynamic relocation
472 needs_dynamic_reloc(bool is_absolute_ref, bool is_function_call) const
474 // An absolute reference within a position-independent output file
475 // will need a dynamic relocaion.
476 if (is_absolute_ref && parameters->output_is_position_independent())
479 // A function call that can branch to a local PLT entry does not need
480 // a dynamic relocation.
481 if (is_function_call && this->has_plt_offset())
484 // A reference to any PLT entry in a non-position-independent executable
485 // does not need a dynamic relocation.
486 if (!parameters->output_is_position_independent()
487 && this->has_plt_offset())
490 // A reference to a symbol defined in a dynamic object or to a
491 // symbol that is preemptible will need a dynamic relocation.
492 if (this->is_from_dynobj() || this->is_preemptible())
495 // For all other cases, return FALSE.
499 // Given a direct absolute static relocation against
500 // the global symbol, where a dynamic relocation is needed, this
501 // function returns whether a relative dynamic relocation can be used.
502 // The caller must determine separately whether the static relocation
503 // is compatible with a relative relocation.
506 can_use_relative_reloc(bool is_function_call) const
508 // A function call that can branch to a local PLT entry can
509 // use a RELATIVE relocation.
510 if (is_function_call && this->has_plt_offset())
513 // A reference to a symbol defined in a dynamic object or to a
514 // symbol that is preemptible can not use a RELATIVE relocaiton.
515 if (this->is_from_dynobj() || this->is_preemptible())
518 // For all other cases, return TRUE.
522 // Return whether there should be a warning for references to this
526 { return this->has_warning_; }
528 // Mark this symbol as having a warning.
531 { this->has_warning_ = true; }
533 // Return whether this symbol is defined by a COPY reloc from a
536 is_copied_from_dynobj() const
537 { return this->is_copied_from_dynobj_; }
539 // Mark this symbol as defined by a COPY reloc.
541 set_is_copied_from_dynobj()
542 { this->is_copied_from_dynobj_ = true; }
545 // Instances of this class should always be created at a specific
548 { memset(this, 0, sizeof *this); }
550 // Initialize the general fields.
552 init_fields(const char* name, const char* version,
553 elfcpp::STT type, elfcpp::STB binding,
554 elfcpp::STV visibility, unsigned char nonvis);
556 // Initialize fields from an ELF symbol in OBJECT.
557 template<int size, bool big_endian>
559 init_base(const char *name, const char* version, Object* object,
560 const elfcpp::Sym<size, big_endian>&);
562 // Initialize fields for an Output_data.
564 init_base(const char* name, Output_data*, elfcpp::STT, elfcpp::STB,
565 elfcpp::STV, unsigned char nonvis, bool offset_is_from_end);
567 // Initialize fields for an Output_segment.
569 init_base(const char* name, Output_segment* os, elfcpp::STT type,
570 elfcpp::STB binding, elfcpp::STV visibility,
571 unsigned char nonvis, Segment_offset_base offset_base);
573 // Initialize fields for a constant.
575 init_base(const char* name, elfcpp::STT type, elfcpp::STB binding,
576 elfcpp::STV visibility, unsigned char nonvis);
578 // Override existing symbol.
579 template<int size, bool big_endian>
581 override_base(const elfcpp::Sym<size, big_endian>&, Object* object,
582 const char* version);
584 // Override existing symbol with a special symbol.
586 override_base_with_special(const Symbol* from);
588 // Allocate a common symbol by giving it a location in the output
591 allocate_base_common(Output_data*);
594 Symbol(const Symbol&);
595 Symbol& operator=(const Symbol&);
597 // Symbol name (expected to point into a Stringpool).
599 // Symbol version (expected to point into a Stringpool). This may
601 const char* version_;
605 // This struct is used if SOURCE_ == FROM_OBJECT.
608 // Object in which symbol is defined, or in which it was first
611 // Section number in object_ in which symbol is defined.
615 // This struct is used if SOURCE_ == IN_OUTPUT_DATA.
618 // Output_data in which symbol is defined. Before
619 // Layout::finalize the symbol's value is an offset within the
621 Output_data* output_data;
622 // True if the offset is from the end, false if the offset is
623 // from the beginning.
624 bool offset_is_from_end;
627 // This struct is used if SOURCE_ == IN_OUTPUT_SEGMENT.
630 // Output_segment in which the symbol is defined. Before
631 // Layout::finalize the symbol's value is an offset.
632 Output_segment* output_segment;
633 // The base to use for the offset before Layout::finalize.
634 Segment_offset_base offset_base;
638 // The index of this symbol in the output file. If the symbol is
639 // not going into the output file, this value is -1U. This field
640 // starts as always holding zero. It is set to a non-zero value by
641 // Symbol_table::finalize.
642 unsigned int symtab_index_;
644 // The index of this symbol in the dynamic symbol table. If the
645 // symbol is not going into the dynamic symbol table, this value is
646 // -1U. This field starts as always holding zero. It is set to a
647 // non-zero value during Layout::finalize.
648 unsigned int dynsym_index_;
650 // If this symbol has an entry in the GOT section (has_got_offset_
651 // is true), this is the offset from the start of the GOT section.
652 // For a TLS symbol, if has_tls_tpoff_got_offset_ is true, this
653 // serves as the GOT offset for the GOT entry that holds its
654 // TP-relative offset.
655 unsigned int got_offset_;
657 // If this is a TLS symbol and has an entry in the GOT section
658 // for a module index or a pair of entries (module index,
659 // dtv-relative offset), these are the offsets from the start
660 // of the GOT section.
661 unsigned int tls_mod_got_offset_;
662 unsigned int tls_pair_got_offset_;
664 // If this symbol has an entry in the PLT section (has_plt_offset_
665 // is true), then this is the offset from the start of the PLT
667 unsigned int plt_offset_;
670 elfcpp::STT type_ : 4;
672 elfcpp::STB binding_ : 4;
673 // Symbol visibility.
674 elfcpp::STV visibility_ : 2;
675 // Rest of symbol st_other field.
676 unsigned int nonvis_ : 6;
677 // The type of symbol.
679 // True if this symbol always requires special target-specific
681 bool is_target_special_ : 1;
682 // True if this is the default version of the symbol.
684 // True if this symbol really forwards to another symbol. This is
685 // used when we discover after the fact that two different entries
686 // in the hash table really refer to the same symbol. This will
687 // never be set for a symbol found in the hash table, but may be set
688 // for a symbol found in the list of symbols attached to an Object.
689 // It forwards to the symbol found in the forwarders_ map of
691 bool is_forwarder_ : 1;
692 // True if the symbol has an alias in the weak_aliases table in
695 // True if this symbol needs to be in the dynamic symbol table.
696 bool needs_dynsym_entry_ : 1;
697 // True if we've seen this symbol in a regular object.
699 // True if we've seen this symbol in a dynamic object.
701 // True if the symbol has an entry in the GOT section.
702 // For a TLS symbol, this GOT entry will hold its tp-relative offset.
703 bool has_got_offset_ : 1;
704 // True if the symbol has an entry in the GOT section for its
706 bool has_tls_mod_got_offset_ : 1;
707 // True if the symbol has a pair of entries in the GOT section for its
708 // module index and dtv-relative offset.
709 bool has_tls_pair_got_offset_ : 1;
710 // True if the symbol has an entry in the PLT section.
711 bool has_plt_offset_ : 1;
712 // True if this is a dynamic symbol which needs a special value in
713 // the dynamic symbol table.
714 bool needs_dynsym_value_ : 1;
715 // True if there is a warning for this symbol.
716 bool has_warning_ : 1;
717 // True if we are using a COPY reloc for this symbol, so that the
718 // real definition lives in a dynamic object.
719 bool is_copied_from_dynobj_ : 1;
722 // The parts of a symbol which are size specific. Using a template
723 // derived class like this helps us use less space on a 32-bit system.
726 class Sized_symbol : public Symbol
729 typedef typename elfcpp::Elf_types<size>::Elf_Addr Value_type;
730 typedef typename elfcpp::Elf_types<size>::Elf_WXword Size_type;
735 // Initialize fields from an ELF symbol in OBJECT.
736 template<bool big_endian>
738 init(const char *name, const char* version, Object* object,
739 const elfcpp::Sym<size, big_endian>&);
741 // Initialize fields for an Output_data.
743 init(const char* name, Output_data*, Value_type value, Size_type symsize,
744 elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis,
745 bool offset_is_from_end);
747 // Initialize fields for an Output_segment.
749 init(const char* name, Output_segment*, Value_type value, Size_type symsize,
750 elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis,
751 Segment_offset_base offset_base);
753 // Initialize fields for a constant.
755 init(const char* name, Value_type value, Size_type symsize,
756 elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis);
758 // Override existing symbol.
759 template<bool big_endian>
761 override(const elfcpp::Sym<size, big_endian>&, Object* object,
762 const char* version);
764 // Override existing symbol with a special symbol.
766 override_with_special(const Sized_symbol<size>*);
768 // Return the symbol's value.
771 { return this->value_; }
773 // Return the symbol's size (we can't call this 'size' because that
774 // is a template parameter).
777 { return this->symsize_; }
779 // Set the symbol size. This is used when resolving common symbols.
781 set_symsize(Size_type symsize)
782 { this->symsize_ = symsize; }
784 // Set the symbol value. This is called when we store the final
785 // values of the symbols into the symbol table.
787 set_value(Value_type value)
788 { this->value_ = value; }
790 // Allocate a common symbol by giving it a location in the output
793 allocate_common(Output_data*, Value_type value);
796 Sized_symbol(const Sized_symbol&);
797 Sized_symbol& operator=(const Sized_symbol&);
799 // Symbol value. Before Layout::finalize this is the offset in the
800 // input section. This is set to the final value during
807 // A struct describing a symbol defined by the linker, where the value
808 // of the symbol is defined based on an output section. This is used
809 // for symbols defined by the linker, like "_init_array_start".
811 struct Define_symbol_in_section
815 // The name of the output section with which this symbol should be
816 // associated. If there is no output section with that name, the
817 // symbol will be defined as zero.
818 const char* output_section;
819 // The offset of the symbol within the output section. This is an
820 // offset from the start of the output section, unless start_at_end
821 // is true, in which case this is an offset from the end of the
824 // The size of the symbol.
828 // The symbol binding.
830 // The symbol visibility.
831 elfcpp::STV visibility;
832 // The rest of the st_other field.
833 unsigned char nonvis;
834 // If true, the value field is an offset from the end of the output
836 bool offset_is_from_end;
837 // If true, this symbol is defined only if we see a reference to it.
841 // A struct describing a symbol defined by the linker, where the value
842 // of the symbol is defined based on a segment. This is used for
843 // symbols defined by the linker, like "_end". We describe the
844 // segment with which the symbol should be associated by its
845 // characteristics. If no segment meets these characteristics, the
846 // symbol will be defined as zero. If there is more than one segment
847 // which meets these characteristics, we will use the first one.
849 struct Define_symbol_in_segment
853 // The segment type where the symbol should be defined, typically
855 elfcpp::PT segment_type;
856 // Bitmask of segment flags which must be set.
857 elfcpp::PF segment_flags_set;
858 // Bitmask of segment flags which must be clear.
859 elfcpp::PF segment_flags_clear;
860 // The offset of the symbol within the segment. The offset is
861 // calculated from the position set by offset_base.
863 // The size of the symbol.
867 // The symbol binding.
869 // The symbol visibility.
870 elfcpp::STV visibility;
871 // The rest of the st_other field.
872 unsigned char nonvis;
873 // The base from which we compute the offset.
874 Symbol::Segment_offset_base offset_base;
875 // If true, this symbol is defined only if we see a reference to it.
879 // This class manages warnings. Warnings are a GNU extension. When
880 // we see a section named .gnu.warning.SYM in an object file, and if
881 // we wind using the definition of SYM from that object file, then we
882 // will issue a warning for any relocation against SYM from a
883 // different object file. The text of the warning is the contents of
884 // the section. This is not precisely the definition used by the old
885 // GNU linker; the old GNU linker treated an occurrence of
886 // .gnu.warning.SYM as defining a warning symbol. A warning symbol
887 // would trigger a warning on any reference. However, it was
888 // inconsistent in that a warning in a dynamic object only triggered
889 // if there was no definition in a regular object. This linker is
890 // different in that we only issue a warning if we use the symbol
891 // definition from the same object file as the warning section.
900 // Add a warning for symbol NAME in object OBJ. WARNING is the text
903 add_warning(Symbol_table* symtab, const char* name, Object* obj,
904 const std::string& warning);
906 // For each symbol for which we should give a warning, make a note
909 note_warnings(Symbol_table* symtab);
911 // Issue a warning for a reference to SYM at RELINFO's location.
912 template<int size, bool big_endian>
914 issue_warning(const Symbol* sym, const Relocate_info<size, big_endian>*,
915 size_t relnum, off_t reloffset) const;
918 Warnings(const Warnings&);
919 Warnings& operator=(const Warnings&);
921 // What we need to know to get the warning text.
922 struct Warning_location
924 // The object the warning is in.
930 : object(NULL), text()
934 set(Object* o, const std::string& t)
941 // A mapping from warning symbol names (canonicalized in
942 // Symbol_table's namepool_ field) to warning information.
943 typedef Unordered_map<const char*, Warning_location> Warning_table;
945 Warning_table warnings_;
948 // The main linker symbol table.
953 // COUNT is an estimate of how many symbosl will be inserted in the
954 // symbol table. It's ok to put 0 if you don't know; a correct
955 // guess will just save some CPU by reducing hashtable resizes.
956 Symbol_table(unsigned int count);
960 // Add COUNT external symbols from the relocatable object RELOBJ to
961 // the symbol table. SYMS is the symbols, SYM_NAMES is their names,
962 // SYM_NAME_SIZE is the size of SYM_NAMES. This sets SYMPOINTERS to
963 // point to the symbols in the symbol table.
964 template<int size, bool big_endian>
966 add_from_relobj(Sized_relobj<size, big_endian>* relobj,
967 const unsigned char* syms, size_t count,
968 const char* sym_names, size_t sym_name_size,
969 typename Sized_relobj<size, big_endian>::Symbols*);
971 // Add COUNT dynamic symbols from the dynamic object DYNOBJ to the
972 // symbol table. SYMS is the symbols. SYM_NAMES is their names.
973 // SYM_NAME_SIZE is the size of SYM_NAMES. The other parameters are
974 // symbol version data.
975 template<int size, bool big_endian>
977 add_from_dynobj(Sized_dynobj<size, big_endian>* dynobj,
978 const unsigned char* syms, size_t count,
979 const char* sym_names, size_t sym_name_size,
980 const unsigned char* versym, size_t versym_size,
981 const std::vector<const char*>*);
983 // Define a special symbol based on an Output_data. It is a
984 // multiple definition error if this symbol is already defined.
986 define_in_output_data(const Target*, const char* name, const char* version,
987 Output_data*, uint64_t value, uint64_t symsize,
988 elfcpp::STT type, elfcpp::STB binding,
989 elfcpp::STV visibility, unsigned char nonvis,
990 bool offset_is_from_end, bool only_if_ref);
992 // Define a special symbol based on an Output_segment. It is a
993 // multiple definition error if this symbol is already defined.
995 define_in_output_segment(const Target*, const char* name,
996 const char* version, Output_segment*,
997 uint64_t value, uint64_t symsize,
998 elfcpp::STT type, elfcpp::STB binding,
999 elfcpp::STV visibility, unsigned char nonvis,
1000 Symbol::Segment_offset_base, bool only_if_ref);
1002 // Define a special symbol with a constant value. It is a multiple
1003 // definition error if this symbol is already defined.
1005 define_as_constant(const Target*, const char* name, const char* version,
1006 uint64_t value, uint64_t symsize, elfcpp::STT type,
1007 elfcpp::STB binding, elfcpp::STV visibility,
1008 unsigned char nonvis, bool only_if_ref);
1010 // Define a set of symbols in output sections.
1012 define_symbols(const Layout*, const Target*, int count,
1013 const Define_symbol_in_section*);
1015 // Define a set of symbols in output segments.
1017 define_symbols(const Layout*, const Target*, int count,
1018 const Define_symbol_in_segment*);
1020 // Define SYM using a COPY reloc. POSD is the Output_data where the
1021 // symbol should be defined--typically a .dyn.bss section. VALUE is
1022 // the offset within POSD.
1025 define_with_copy_reloc(const Target*, Sized_symbol<size>* sym,
1027 typename elfcpp::Elf_types<size>::Elf_Addr);
1029 // Look up a symbol.
1031 lookup(const char*, const char* version = NULL) const;
1033 // Return the real symbol associated with the forwarder symbol FROM.
1035 resolve_forwards(const Symbol* from) const;
1037 // Return the sized version of a symbol in this table.
1040 get_sized_symbol(Symbol* ACCEPT_SIZE) const;
1043 const Sized_symbol<size>*
1044 get_sized_symbol(const Symbol* ACCEPT_SIZE) const;
1046 // Return the count of undefined symbols seen.
1048 saw_undefined() const
1049 { return this->saw_undefined_; }
1051 // Allocate the common symbols
1053 allocate_commons(const General_options&, Layout*);
1055 // Add a warning for symbol NAME in object OBJ. WARNING is the text
1058 add_warning(const char* name, Object* obj, const std::string& warning)
1059 { this->warnings_.add_warning(this, name, obj, warning); }
1061 // Canonicalize a symbol name for use in the hash table.
1063 canonicalize_name(const char* name)
1064 { return this->namepool_.add(name, true, NULL); }
1066 // Possibly issue a warning for a reference to SYM at LOCATION which
1068 template<int size, bool big_endian>
1070 issue_warning(const Symbol* sym,
1071 const Relocate_info<size, big_endian>* relinfo,
1072 size_t relnum, off_t reloffset) const
1073 { this->warnings_.issue_warning(sym, relinfo, relnum, reloffset); }
1075 // Check candidate_odr_violations_ to find symbols with the same name
1076 // but apparently different definitions (different source-file/line-no).
1078 detect_odr_violations(const Task*, const char* output_file_name) const;
1080 // SYM is defined using a COPY reloc. Return the dynamic object
1081 // where the original definition was found.
1083 get_copy_source(const Symbol* sym) const;
1085 // Set the dynamic symbol indexes. INDEX is the index of the first
1086 // global dynamic symbol. Pointers to the symbols are stored into
1087 // the vector. The names are stored into the Stringpool. This
1088 // returns an updated dynamic symbol index.
1090 set_dynsym_indexes(const Target*, unsigned int index,
1091 std::vector<Symbol*>*, Stringpool*, Versions*);
1093 // Finalize the symbol table after we have set the final addresses
1094 // of all the input sections. This sets the final symbol indexes,
1095 // values and adds the names to *POOL. INDEX is the index of the
1096 // first global symbol. OFF is the file offset of the global symbol
1097 // table, DYNOFF is the offset of the globals in the dynamic symbol
1098 // table, DYN_GLOBAL_INDEX is the index of the first global dynamic
1099 // symbol, and DYNCOUNT is the number of global dynamic symbols.
1100 // This records the parameters, and returns the new file offset.
1102 finalize(unsigned int index, off_t off, off_t dynoff,
1103 size_t dyn_global_index, size_t dyncount, Stringpool* pool);
1105 // Write out the global symbols.
1107 write_globals(const Input_objects*, const Stringpool*, const Stringpool*,
1108 Output_file*) const;
1110 // Write out a section symbol. Return the updated offset.
1112 write_section_symbol(const Output_section*, Output_file*, off_t) const;
1114 // Dump statistical information to stderr.
1116 print_stats() const;
1119 Symbol_table(const Symbol_table&);
1120 Symbol_table& operator=(const Symbol_table&);
1122 // Make FROM a forwarder symbol to TO.
1124 make_forwarder(Symbol* from, Symbol* to);
1127 template<int size, bool big_endian>
1129 add_from_object(Object*, const char *name, Stringpool::Key name_key,
1130 const char *version, Stringpool::Key version_key,
1131 bool def, const elfcpp::Sym<size, big_endian>& sym,
1132 const elfcpp::Sym<size, big_endian>& orig_sym);
1135 template<int size, bool big_endian>
1137 resolve(Sized_symbol<size>* to,
1138 const elfcpp::Sym<size, big_endian>& sym,
1139 const elfcpp::Sym<size, big_endian>& orig_sym,
1140 Object*, const char* version);
1142 template<int size, bool big_endian>
1144 resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from,
1145 const char* version ACCEPT_SIZE_ENDIAN);
1147 // Whether we should override a symbol, based on flags in
1150 should_override(const Symbol*, unsigned int, Object*, bool*);
1152 // Override a symbol.
1153 template<int size, bool big_endian>
1155 override(Sized_symbol<size>* tosym,
1156 const elfcpp::Sym<size, big_endian>& fromsym,
1157 Object* object, const char* version);
1159 // Whether we should override a symbol with a special symbol which
1160 // is automatically defined by the linker.
1162 should_override_with_special(const Symbol*);
1164 // Override a symbol with a special symbol.
1167 override_with_special(Sized_symbol<size>* tosym,
1168 const Sized_symbol<size>* fromsym);
1170 // Record all weak alias sets for a dynamic object.
1173 record_weak_aliases(std::vector<Sized_symbol<size>*>*);
1175 // Define a special symbol.
1176 template<int size, bool big_endian>
1178 define_special_symbol(const Target* target, const char** pname,
1179 const char** pversion, bool only_if_ref,
1180 Sized_symbol<size>** poldsym ACCEPT_SIZE_ENDIAN);
1182 // Define a symbol in an Output_data, sized version.
1185 do_define_in_output_data(const Target*, const char* name,
1186 const char* version, Output_data*,
1187 typename elfcpp::Elf_types<size>::Elf_Addr value,
1188 typename elfcpp::Elf_types<size>::Elf_WXword ssize,
1189 elfcpp::STT type, elfcpp::STB binding,
1190 elfcpp::STV visibility, unsigned char nonvis,
1191 bool offset_is_from_end, bool only_if_ref);
1193 // Define a symbol in an Output_segment, sized version.
1196 do_define_in_output_segment(
1197 const Target*, const char* name, const char* version, Output_segment* os,
1198 typename elfcpp::Elf_types<size>::Elf_Addr value,
1199 typename elfcpp::Elf_types<size>::Elf_WXword ssize,
1200 elfcpp::STT type, elfcpp::STB binding,
1201 elfcpp::STV visibility, unsigned char nonvis,
1202 Symbol::Segment_offset_base offset_base, bool only_if_ref);
1204 // Define a symbol as a constant, sized version.
1207 do_define_as_constant(
1208 const Target*, const char* name, const char* version,
1209 typename elfcpp::Elf_types<size>::Elf_Addr value,
1210 typename elfcpp::Elf_types<size>::Elf_WXword ssize,
1211 elfcpp::STT type, elfcpp::STB binding,
1212 elfcpp::STV visibility, unsigned char nonvis,
1215 // Allocate the common symbols, sized version.
1218 do_allocate_commons(const General_options&, Layout*);
1220 // Implement detect_odr_violations.
1221 template<int size, bool big_endian>
1223 sized_detect_odr_violations() const;
1225 // Finalize symbols specialized for size.
1228 sized_finalize(unsigned int, off_t, Stringpool*);
1230 // Write globals specialized for size and endianness.
1231 template<int size, bool big_endian>
1233 sized_write_globals(const Input_objects*, const Stringpool*,
1234 const Stringpool*, Output_file*) const;
1236 // Write out a symbol to P.
1237 template<int size, bool big_endian>
1239 sized_write_symbol(Sized_symbol<size>*,
1240 typename elfcpp::Elf_types<size>::Elf_Addr value,
1242 const Stringpool*, unsigned char* p
1243 ACCEPT_SIZE_ENDIAN) const;
1245 // Possibly warn about an undefined symbol from a dynamic object.
1247 warn_about_undefined_dynobj_symbol(const Input_objects*, Symbol*) const;
1249 // Write out a section symbol, specialized for size and endianness.
1250 template<int size, bool big_endian>
1252 sized_write_section_symbol(const Output_section*, Output_file*, off_t) const;
1254 // The type of the symbol hash table.
1256 typedef std::pair<Stringpool::Key, Stringpool::Key> Symbol_table_key;
1258 struct Symbol_table_hash
1261 operator()(const Symbol_table_key&) const;
1264 struct Symbol_table_eq
1267 operator()(const Symbol_table_key&, const Symbol_table_key&) const;
1270 typedef Unordered_map<Symbol_table_key, Symbol*, Symbol_table_hash,
1271 Symbol_table_eq> Symbol_table_type;
1273 // The type of the list of common symbols.
1274 typedef std::vector<Symbol*> Commons_type;
1276 // A map from symbols with COPY relocs to the dynamic objects where
1277 // they are defined.
1278 typedef Unordered_map<const Symbol*, Dynobj*> Copied_symbol_dynobjs;
1280 // A map from symbol name (as a pointer into the namepool) to all
1281 // the locations the symbols is (weakly) defined (and certain other
1282 // conditions are met). This map will be used later to detect
1283 // possible One Definition Rule (ODR) violations.
1284 struct Symbol_location
1286 Object* object; // Object where the symbol is defined.
1287 unsigned int shndx; // Section-in-object where the symbol is defined.
1288 off_t offset; // Offset-in-section where the symbol is defined.
1289 bool operator==(const Symbol_location& that) const
1291 return (this->object == that.object
1292 && this->shndx == that.shndx
1293 && this->offset == that.offset);
1297 struct Symbol_location_hash
1299 size_t operator()(const Symbol_location& loc) const
1300 { return reinterpret_cast<uintptr_t>(loc.object) ^ loc.offset ^ loc.shndx; }
1303 typedef Unordered_map<const char*,
1304 Unordered_set<Symbol_location, Symbol_location_hash> >
1307 // We increment this every time we see a new undefined symbol, for
1308 // use in archive groups.
1310 // The index of the first global symbol in the output file.
1311 unsigned int first_global_index_;
1312 // The file offset within the output symtab section where we should
1315 // The number of global symbols we want to write out.
1316 size_t output_count_;
1317 // The file offset of the global dynamic symbols, or 0 if none.
1318 off_t dynamic_offset_;
1319 // The index of the first global dynamic symbol.
1320 unsigned int first_dynamic_global_index_;
1321 // The number of global dynamic symbols, or 0 if none.
1322 off_t dynamic_count_;
1323 // The symbol hash table.
1324 Symbol_table_type table_;
1325 // A pool of symbol names. This is used for all global symbols.
1326 // Entries in the hash table point into this pool.
1327 Stringpool namepool_;
1328 // Forwarding symbols.
1329 Unordered_map<const Symbol*, Symbol*> forwarders_;
1330 // Weak aliases. A symbol in this list points to the next alias.
1331 // The aliases point to each other in a circular list.
1332 Unordered_map<Symbol*, Symbol*> weak_aliases_;
1333 // We don't expect there to be very many common symbols, so we keep
1334 // a list of them. When we find a common symbol we add it to this
1335 // list. It is possible that by the time we process the list the
1336 // symbol is no longer a common symbol. It may also have become a
1338 Commons_type commons_;
1339 // Manage symbol warnings.
1341 // Manage potential One Definition Rule (ODR) violations.
1342 Odr_map candidate_odr_violations_;
1344 // When we emit a COPY reloc for a symbol, we define it in an
1345 // Output_data. When it's time to emit version information for it,
1346 // we need to know the dynamic object in which we found the original
1347 // definition. This maps symbols with COPY relocs to the dynamic
1348 // object where they were defined.
1349 Copied_symbol_dynobjs copied_symbol_dynobjs_;
1352 // We inline get_sized_symbol for efficiency.
1356 Symbol_table::get_sized_symbol(Symbol* sym ACCEPT_SIZE) const
1358 gold_assert(size == parameters->get_size());
1359 return static_cast<Sized_symbol<size>*>(sym);
1363 const Sized_symbol<size>*
1364 Symbol_table::get_sized_symbol(const Symbol* sym ACCEPT_SIZE) const
1366 gold_assert(size == parameters->get_size());
1367 return static_cast<const Sized_symbol<size>*>(sym);
1370 } // End namespace gold.
1372 #endif // !defined(GOLD_SYMTAB_H)