1 // symtab.h -- the gold symbol table -*- C++ -*-
3 // Copyright (C) 2006-2017 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.
34 #include "parameters.h"
35 #include "stringpool.h"
44 template<int size, bool big_endian>
45 class Sized_relobj_file;
46 template<int size, bool big_endian>
47 class Sized_pluginobj;
49 template<int size, bool big_endian>
51 template<int size, bool big_endian>
54 class Version_script_info;
60 class Output_symtab_xindex;
61 class Garbage_collection;
64 // The base class of an entry in the symbol table. The symbol table
65 // can have a lot of entries, so we don't want this class too big.
66 // Size dependent fields can be found in the template class
67 // Sized_symbol. Targets may support their own derived classes.
72 // Because we want the class to be small, we don't use any virtual
73 // functions. But because symbols can be defined in different
74 // places, we need to classify them. This enum is the different
75 // sources of symbols we support.
78 // Symbol defined in a relocatable or dynamic input file--this is
79 // the most common case.
81 // Symbol defined in an Output_data, a special section created by
84 // Symbol defined in an Output_segment, with no associated
87 // Symbol value is constant.
89 // Symbol is undefined.
93 // When the source is IN_OUTPUT_SEGMENT, we need to describe what
95 enum Segment_offset_base
97 // From the start of the segment.
99 // From the end of the segment.
101 // From the filesz of the segment--i.e., after the loaded bytes
102 // but before the bytes which are allocated but zeroed.
106 // Return the symbol name.
109 { return this->name_; }
111 // Return the (ANSI) demangled version of the name, if
112 // parameters.demangle() is true. Otherwise, return the name. This
113 // is intended to be used only for logging errors, so it's not
116 demangled_name() const;
118 // Return the symbol version. This will return NULL for an
119 // unversioned symbol.
122 { return this->version_; }
126 { this->version_ = NULL; }
128 // Return whether this version is the default for this symbol name
129 // (eg, "foo@@V2" is a default version; "foo@V1" is not). Only
130 // meaningful for versioned symbols.
134 gold_assert(this->version_ != NULL);
135 return this->is_def_;
138 // Set that this version is the default for this symbol name.
141 { this->is_def_ = true; }
143 // Set that this version is not the default for this symbol name.
146 { this->is_def_ = false; }
148 // Return the symbol's name as name@version (or name@@version).
150 versioned_name() const;
152 // Return the symbol source.
155 { return this->source_; }
157 // Return the object with which this symbol is associated.
161 gold_assert(this->source_ == FROM_OBJECT);
162 return this->u_.from_object.object;
165 // Return the index of the section in the input relocatable or
166 // dynamic object file.
168 shndx(bool* is_ordinary) const
170 gold_assert(this->source_ == FROM_OBJECT);
171 *is_ordinary = this->is_ordinary_shndx_;
172 return this->u_.from_object.shndx;
175 // Return the output data section with which this symbol is
176 // associated, if the symbol was specially defined with respect to
177 // an output data section.
181 gold_assert(this->source_ == IN_OUTPUT_DATA);
182 return this->u_.in_output_data.output_data;
185 // If this symbol was defined with respect to an output data
186 // section, return whether the value is an offset from end.
188 offset_is_from_end() const
190 gold_assert(this->source_ == IN_OUTPUT_DATA);
191 return this->u_.in_output_data.offset_is_from_end;
194 // Return the output segment with which this symbol is associated,
195 // if the symbol was specially defined with respect to an output
198 output_segment() const
200 gold_assert(this->source_ == IN_OUTPUT_SEGMENT);
201 return this->u_.in_output_segment.output_segment;
204 // If this symbol was defined with respect to an output segment,
205 // return the offset base.
209 gold_assert(this->source_ == IN_OUTPUT_SEGMENT);
210 return this->u_.in_output_segment.offset_base;
213 // Return the symbol binding.
216 { return this->binding_; }
218 // Return the symbol type.
221 { return this->type_; }
223 // Set the symbol type.
225 set_type(elfcpp::STT type)
226 { this->type_ = type; }
228 // Return true for function symbol.
232 return (this->type_ == elfcpp::STT_FUNC
233 || this->type_ == elfcpp::STT_GNU_IFUNC);
236 // Return the symbol visibility.
239 { return this->visibility_; }
241 // Set the visibility.
243 set_visibility(elfcpp::STV visibility)
244 { this->visibility_ = visibility; }
246 // Override symbol visibility.
248 override_visibility(elfcpp::STV);
250 // Set whether the symbol was originally a weak undef or a regular undef
251 // when resolved by a dynamic def or by a special symbol.
253 set_undef_binding(elfcpp::STB bind)
255 if (!this->undef_binding_set_ || this->undef_binding_weak_)
257 this->undef_binding_weak_ = bind == elfcpp::STB_WEAK;
258 this->undef_binding_set_ = true;
262 // Return TRUE if a weak undef was resolved by a dynamic def or
263 // by a special symbol.
265 is_undef_binding_weak() const
266 { return this->undef_binding_weak_; }
268 // Return the non-visibility part of the st_other field.
271 { return this->nonvis_; }
273 // Set the non-visibility part of the st_other field.
275 set_nonvis(unsigned int nonvis)
276 { this->nonvis_ = nonvis; }
278 // Return whether this symbol is a forwarder. This will never be
279 // true of a symbol found in the hash table, but may be true of
280 // symbol pointers attached to object files.
283 { return this->is_forwarder_; }
285 // Mark this symbol as a forwarder.
288 { this->is_forwarder_ = true; }
290 // Return whether this symbol has an alias in the weak aliases table
294 { return this->has_alias_; }
296 // Mark this symbol as having an alias.
299 { this->has_alias_ = true; }
301 // Return whether this symbol needs an entry in the dynamic symbol
304 needs_dynsym_entry() const
306 return (this->needs_dynsym_entry_
309 && this->is_externally_visible()));
312 // Mark this symbol as needing an entry in the dynamic symbol table.
314 set_needs_dynsym_entry()
315 { this->needs_dynsym_entry_ = true; }
317 // Return whether this symbol should be added to the dynamic symbol
320 should_add_dynsym_entry(Symbol_table*) const;
322 // Return whether this symbol has been seen in a regular object.
325 { return this->in_reg_; }
327 // Mark this symbol as having been seen in a regular object.
330 { this->in_reg_ = true; }
332 // Return whether this symbol has been seen in a dynamic object.
335 { return this->in_dyn_; }
337 // Mark this symbol as having been seen in a dynamic object.
340 { this->in_dyn_ = true; }
342 // Return whether this symbol has been seen in a real ELF object.
343 // (IN_REG will return TRUE if the symbol has been seen in either
344 // a real ELF object or an object claimed by a plugin.)
347 { return this->in_real_elf_; }
349 // Mark this symbol as having been seen in a real ELF object.
352 { this->in_real_elf_ = true; }
354 // Return whether this symbol was defined in a section that was
355 // discarded from the link. This is used to control some error
358 is_defined_in_discarded_section() const
359 { return this->is_defined_in_discarded_section_; }
361 // Mark this symbol as having been defined in a discarded section.
363 set_is_defined_in_discarded_section()
364 { this->is_defined_in_discarded_section_ = true; }
366 // Return the index of this symbol in the output file symbol table.
367 // A value of -1U means that this symbol is not going into the
368 // output file. This starts out as zero, and is set to a non-zero
369 // value by Symbol_table::finalize. It is an error to ask for the
370 // symbol table index before it has been set.
374 gold_assert(this->symtab_index_ != 0);
375 return this->symtab_index_;
378 // Set the index of the symbol in the output file symbol table.
380 set_symtab_index(unsigned int index)
382 gold_assert(index != 0);
383 this->symtab_index_ = index;
386 // Return whether this symbol already has an index in the output
387 // file symbol table.
389 has_symtab_index() const
390 { return this->symtab_index_ != 0; }
392 // Return the index of this symbol in the dynamic symbol table. A
393 // value of -1U means that this symbol is not going into the dynamic
394 // symbol table. This starts out as zero, and is set to a non-zero
395 // during Layout::finalize. It is an error to ask for the dynamic
396 // symbol table index before it has been set.
400 gold_assert(this->dynsym_index_ != 0);
401 return this->dynsym_index_;
404 // Set the index of the symbol in the dynamic symbol table.
406 set_dynsym_index(unsigned int index)
408 gold_assert(index != 0);
409 this->dynsym_index_ = index;
412 // Return whether this symbol already has an index in the dynamic
415 has_dynsym_index() const
416 { return this->dynsym_index_ != 0; }
418 // Return whether this symbol has an entry in the GOT section.
419 // For a TLS symbol, this GOT entry will hold its tp-relative offset.
421 has_got_offset(unsigned int got_type) const
422 { return this->got_offsets_.get_offset(got_type) != -1U; }
424 // Return the offset into the GOT section of this symbol.
426 got_offset(unsigned int got_type) const
428 unsigned int got_offset = this->got_offsets_.get_offset(got_type);
429 gold_assert(got_offset != -1U);
433 // Set the GOT offset of this symbol.
435 set_got_offset(unsigned int got_type, unsigned int got_offset)
436 { this->got_offsets_.set_offset(got_type, got_offset); }
438 // Return the GOT offset list.
439 const Got_offset_list*
440 got_offset_list() const
441 { return this->got_offsets_.get_list(); }
443 // Return whether this symbol has an entry in the PLT section.
445 has_plt_offset() const
446 { return this->plt_offset_ != -1U; }
448 // Return the offset into the PLT section of this symbol.
452 gold_assert(this->has_plt_offset());
453 return this->plt_offset_;
456 // Set the PLT offset of this symbol.
458 set_plt_offset(unsigned int plt_offset)
460 gold_assert(plt_offset != -1U);
461 this->plt_offset_ = plt_offset;
464 // Return whether this dynamic symbol needs a special value in the
465 // dynamic symbol table.
467 needs_dynsym_value() const
468 { return this->needs_dynsym_value_; }
470 // Set that this dynamic symbol needs a special value in the dynamic
473 set_needs_dynsym_value()
475 gold_assert(this->object()->is_dynamic());
476 this->needs_dynsym_value_ = true;
479 // Return true if the final value of this symbol is known at link
482 final_value_is_known() const;
484 // Return true if SHNDX represents a common symbol. This depends on
487 is_common_shndx(unsigned int shndx);
489 // Return whether this is a defined symbol (not undefined or
495 if (this->source_ != FROM_OBJECT)
496 return this->source_ != IS_UNDEFINED;
497 unsigned int shndx = this->shndx(&is_ordinary);
499 ? shndx != elfcpp::SHN_UNDEF
500 : !Symbol::is_common_shndx(shndx));
503 // Return true if this symbol is from a dynamic object.
505 is_from_dynobj() const
507 return this->source_ == FROM_OBJECT && this->object()->is_dynamic();
510 // Return whether this is a placeholder symbol from a plugin object.
512 is_placeholder() const
514 return this->source_ == FROM_OBJECT && this->object()->pluginobj() != NULL;
517 // Return whether this is an undefined symbol.
522 return ((this->source_ == FROM_OBJECT
523 && this->shndx(&is_ordinary) == elfcpp::SHN_UNDEF
525 || this->source_ == IS_UNDEFINED);
528 // Return whether this is a weak undefined symbol.
530 is_weak_undefined() const
532 return (this->is_undefined()
533 && (this->binding() == elfcpp::STB_WEAK
534 || this->is_undef_binding_weak()
535 || parameters->options().weak_unresolved_symbols()));
538 // Return whether this is a strong undefined symbol.
540 is_strong_undefined() const
542 return (this->is_undefined()
543 && this->binding() != elfcpp::STB_WEAK
544 && !this->is_undef_binding_weak()
545 && !parameters->options().weak_unresolved_symbols());
548 // Return whether this is an absolute symbol.
553 return ((this->source_ == FROM_OBJECT
554 && this->shndx(&is_ordinary) == elfcpp::SHN_ABS
556 || this->source_ == IS_CONSTANT);
559 // Return whether this is a common symbol.
563 if (this->source_ != FROM_OBJECT)
566 unsigned int shndx = this->shndx(&is_ordinary);
567 return !is_ordinary && Symbol::is_common_shndx(shndx);
570 // Return whether this symbol can be seen outside this object.
572 is_externally_visible() const
574 return ((this->visibility_ == elfcpp::STV_DEFAULT
575 || this->visibility_ == elfcpp::STV_PROTECTED)
576 && !this->is_forced_local_);
579 // Return true if this symbol can be preempted by a definition in
580 // another link unit.
582 is_preemptible() const
584 // It doesn't make sense to ask whether a symbol defined in
585 // another object is preemptible.
586 gold_assert(!this->is_from_dynobj());
588 // It doesn't make sense to ask whether an undefined symbol
590 gold_assert(!this->is_undefined());
592 // If a symbol does not have default visibility, it can not be
593 // seen outside this link unit and therefore is not preemptible.
594 if (this->visibility_ != elfcpp::STV_DEFAULT)
597 // If this symbol has been forced to be a local symbol by a
598 // version script, then it is not visible outside this link unit
599 // and is not preemptible.
600 if (this->is_forced_local_)
603 // If we are not producing a shared library, then nothing is
605 if (!parameters->options().shared())
608 // If the symbol was named in a --dynamic-list script, it is preemptible.
609 if (parameters->options().in_dynamic_list(this->name()))
612 // If the user used -Bsymbolic, then nothing (else) is preemptible.
613 if (parameters->options().Bsymbolic())
616 // If the user used -Bsymbolic-functions, then functions are not
617 // preemptible. We explicitly check for not being STT_OBJECT,
618 // rather than for being STT_FUNC, because that is what the GNU
620 if (this->type() != elfcpp::STT_OBJECT
621 && parameters->options().Bsymbolic_functions())
624 // Otherwise the symbol is preemptible.
628 // Return true if this symbol is a function that needs a PLT entry.
630 needs_plt_entry() const
632 // An undefined symbol from an executable does not need a PLT entry.
633 if (this->is_undefined() && !parameters->options().shared())
636 // An STT_GNU_IFUNC symbol always needs a PLT entry, even when
637 // doing a static link.
638 if (this->type() == elfcpp::STT_GNU_IFUNC)
641 // We only need a PLT entry for a function.
642 if (!this->is_func())
645 // If we're doing a static link or a -pie link, we don't create
647 if (parameters->doing_static_link()
648 || parameters->options().pie())
651 // We need a PLT entry if the function is defined in a dynamic
652 // object, or is undefined when building a shared object, or if it
653 // is subject to pre-emption.
654 return (this->is_from_dynobj()
655 || this->is_undefined()
656 || this->is_preemptible());
659 // When determining whether a reference to a symbol needs a dynamic
660 // relocation, we need to know several things about the reference.
661 // These flags may be or'ed together. 0 means that the symbol
662 // isn't referenced at all.
665 // A reference to the symbol's absolute address. This includes
666 // references that cause an absolute address to be stored in the GOT.
668 // A reference that calculates the offset of the symbol from some
669 // anchor point, such as the PC or GOT.
671 // A TLS-related reference.
673 // A reference that can always be treated as a function call.
675 // When set, says that dynamic relocations are needed even if a
676 // symbol has a plt entry.
680 // Given a direct absolute or pc-relative static relocation against
681 // the global symbol, this function returns whether a dynamic relocation
685 needs_dynamic_reloc(int flags) const
687 // No dynamic relocations in a static link!
688 if (parameters->doing_static_link())
691 // A reference to an undefined symbol from an executable should be
692 // statically resolved to 0, and does not need a dynamic relocation.
693 // This matches gnu ld behavior.
694 if (this->is_undefined() && !parameters->options().shared())
697 // A reference to an absolute symbol does not need a dynamic relocation.
698 if (this->is_absolute())
701 // An absolute reference within a position-independent output file
702 // will need a dynamic relocation.
703 if ((flags & ABSOLUTE_REF)
704 && parameters->options().output_is_position_independent())
707 // A function call that can branch to a local PLT entry does not need
708 // a dynamic relocation.
709 if ((flags & FUNCTION_CALL) && this->has_plt_offset())
712 // A reference to any PLT entry in a non-position-independent executable
713 // does not need a dynamic relocation.
714 if (!(flags & FUNC_DESC_ABI)
715 && !parameters->options().output_is_position_independent()
716 && this->has_plt_offset())
719 // A reference to a symbol defined in a dynamic object or to a
720 // symbol that is preemptible will need a dynamic relocation.
721 if (this->is_from_dynobj()
722 || this->is_undefined()
723 || this->is_preemptible())
726 // For all other cases, return FALSE.
730 // Whether we should use the PLT offset associated with a symbol for
731 // a relocation. FLAGS is a set of Reference_flags.
734 use_plt_offset(int flags) const
736 // If the symbol doesn't have a PLT offset, then naturally we
737 // don't want to use it.
738 if (!this->has_plt_offset())
741 // For a STT_GNU_IFUNC symbol we always have to use the PLT entry.
742 if (this->type() == elfcpp::STT_GNU_IFUNC)
745 // If we are going to generate a dynamic relocation, then we will
746 // wind up using that, so no need to use the PLT entry.
747 if (this->needs_dynamic_reloc(flags))
750 // If the symbol is from a dynamic object, we need to use the PLT
752 if (this->is_from_dynobj())
755 // If we are generating a shared object, and this symbol is
756 // undefined or preemptible, we need to use the PLT entry.
757 if (parameters->options().shared()
758 && (this->is_undefined() || this->is_preemptible()))
761 // If this is a call to a weak undefined symbol, we need to use
762 // the PLT entry; the symbol may be defined by a library loaded
764 if ((flags & FUNCTION_CALL) && this->is_weak_undefined())
767 // Otherwise we can use the regular definition.
771 // Given a direct absolute static relocation against
772 // the global symbol, where a dynamic relocation is needed, this
773 // function returns whether a relative dynamic relocation can be used.
774 // The caller must determine separately whether the static relocation
775 // is compatible with a relative relocation.
778 can_use_relative_reloc(bool is_function_call) const
780 // A function call that can branch to a local PLT entry can
781 // use a RELATIVE relocation.
782 if (is_function_call && this->has_plt_offset())
785 // A reference to a symbol defined in a dynamic object or to a
786 // symbol that is preemptible can not use a RELATIVE relocation.
787 if (this->is_from_dynobj()
788 || this->is_undefined()
789 || this->is_preemptible())
792 // For all other cases, return TRUE.
796 // Return the output section where this symbol is defined. Return
797 // NULL if the symbol has an absolute value.
799 output_section() const;
801 // Set the symbol's output section. This is used for symbols
802 // defined in scripts. This should only be called after the symbol
803 // table has been finalized.
805 set_output_section(Output_section*);
807 // Set the symbol's output segment. This is used for pre-defined
808 // symbols whose segments aren't known until after layout is done
809 // (e.g., __ehdr_start).
811 set_output_segment(Output_segment*, Segment_offset_base);
813 // Set the symbol to undefined. This is used for pre-defined
814 // symbols whose segments aren't known until after layout is done
815 // (e.g., __ehdr_start).
819 // Return whether there should be a warning for references to this
823 { return this->has_warning_; }
825 // Mark this symbol as having a warning.
828 { this->has_warning_ = true; }
830 // Return whether this symbol is defined by a COPY reloc from a
833 is_copied_from_dynobj() const
834 { return this->is_copied_from_dynobj_; }
836 // Mark this symbol as defined by a COPY reloc.
838 set_is_copied_from_dynobj()
839 { this->is_copied_from_dynobj_ = true; }
841 // Return whether this symbol is forced to visibility STB_LOCAL
842 // by a "local:" entry in a version script.
844 is_forced_local() const
845 { return this->is_forced_local_; }
847 // Mark this symbol as forced to STB_LOCAL visibility.
849 set_is_forced_local()
850 { this->is_forced_local_ = true; }
852 // Return true if this may need a COPY relocation.
853 // References from an executable object to non-function symbols
854 // defined in a dynamic object may need a COPY relocation.
856 may_need_copy_reloc() const
858 return (parameters->options().copyreloc()
859 && this->is_from_dynobj()
860 && !this->is_func());
863 // Return true if this symbol was predefined by the linker.
865 is_predefined() const
866 { return this->is_predefined_; }
868 // Return true if this is a C++ vtable symbol.
870 is_cxx_vtable() const
871 { return is_prefix_of("_ZTV", this->name_); }
873 // Return true if this symbol is protected in a shared object.
874 // This is not the same as checking if visibility() == elfcpp::STV_PROTECTED,
875 // because the visibility_ field reflects the symbol's visibility from
876 // outside the shared object.
879 { return this->is_protected_; }
881 // Mark this symbol as protected in a shared object.
884 { this->is_protected_ = true; }
887 // Instances of this class should always be created at a specific
890 { memset(this, 0, sizeof *this); }
892 // Initialize the general fields.
894 init_fields(const char* name, const char* version,
895 elfcpp::STT type, elfcpp::STB binding,
896 elfcpp::STV visibility, unsigned char nonvis);
898 // Initialize fields from an ELF symbol in OBJECT. ST_SHNDX is the
899 // section index, IS_ORDINARY is whether it is a normal section
900 // index rather than a special code.
901 template<int size, bool big_endian>
903 init_base_object(const char* name, const char* version, Object* object,
904 const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
907 // Initialize fields for an Output_data.
909 init_base_output_data(const char* name, const char* version, Output_data*,
910 elfcpp::STT, elfcpp::STB, elfcpp::STV,
911 unsigned char nonvis, bool offset_is_from_end,
914 // Initialize fields for an Output_segment.
916 init_base_output_segment(const char* name, const char* version,
917 Output_segment* os, elfcpp::STT type,
918 elfcpp::STB binding, elfcpp::STV visibility,
919 unsigned char nonvis,
920 Segment_offset_base offset_base,
923 // Initialize fields for a constant.
925 init_base_constant(const char* name, const char* version, elfcpp::STT type,
926 elfcpp::STB binding, elfcpp::STV visibility,
927 unsigned char nonvis, bool is_predefined);
929 // Initialize fields for an undefined symbol.
931 init_base_undefined(const char* name, const char* version, elfcpp::STT type,
932 elfcpp::STB binding, elfcpp::STV visibility,
933 unsigned char nonvis);
935 // Override existing symbol.
936 template<int size, bool big_endian>
938 override_base(const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
939 bool is_ordinary, Object* object, const char* version);
941 // Override existing symbol with a special symbol.
943 override_base_with_special(const Symbol* from);
945 // Override symbol version.
947 override_version(const char* version);
949 // Allocate a common symbol by giving it a location in the output
952 allocate_base_common(Output_data*);
955 Symbol(const Symbol&);
956 Symbol& operator=(const Symbol&);
958 // Symbol name (expected to point into a Stringpool).
960 // Symbol version (expected to point into a Stringpool). This may
962 const char* version_;
966 // This struct is used if SOURCE_ == FROM_OBJECT.
969 // Object in which symbol is defined, or in which it was first
972 // Section number in object_ in which symbol is defined.
976 // This struct is used if SOURCE_ == IN_OUTPUT_DATA.
979 // Output_data in which symbol is defined. Before
980 // Layout::finalize the symbol's value is an offset within the
982 Output_data* output_data;
983 // True if the offset is from the end, false if the offset is
984 // from the beginning.
985 bool offset_is_from_end;
988 // This struct is used if SOURCE_ == IN_OUTPUT_SEGMENT.
991 // Output_segment in which the symbol is defined. Before
992 // Layout::finalize the symbol's value is an offset.
993 Output_segment* output_segment;
994 // The base to use for the offset before Layout::finalize.
995 Segment_offset_base offset_base;
999 // The index of this symbol in the output file. If the symbol is
1000 // not going into the output file, this value is -1U. This field
1001 // starts as always holding zero. It is set to a non-zero value by
1002 // Symbol_table::finalize.
1003 unsigned int symtab_index_;
1005 // The index of this symbol in the dynamic symbol table. If the
1006 // symbol is not going into the dynamic symbol table, this value is
1007 // -1U. This field starts as always holding zero. It is set to a
1008 // non-zero value during Layout::finalize.
1009 unsigned int dynsym_index_;
1011 // The GOT section entries for this symbol. A symbol may have more
1012 // than one GOT offset (e.g., when mixing modules compiled with two
1013 // different TLS models), but will usually have at most one.
1014 Got_offset_list got_offsets_;
1016 // If this symbol has an entry in the PLT section, then this is the
1017 // offset from the start of the PLT section. This is -1U if there
1019 unsigned int plt_offset_;
1021 // Symbol type (bits 0 to 3).
1022 elfcpp::STT type_ : 4;
1023 // Symbol binding (bits 4 to 7).
1024 elfcpp::STB binding_ : 4;
1025 // Symbol visibility (bits 8 to 9).
1026 elfcpp::STV visibility_ : 2;
1027 // Rest of symbol st_other field (bits 10 to 15).
1028 unsigned int nonvis_ : 6;
1029 // The type of symbol (bits 16 to 18).
1031 // True if this is the default version of the symbol (bit 19).
1033 // True if this symbol really forwards to another symbol. This is
1034 // used when we discover after the fact that two different entries
1035 // in the hash table really refer to the same symbol. This will
1036 // never be set for a symbol found in the hash table, but may be set
1037 // for a symbol found in the list of symbols attached to an Object.
1038 // It forwards to the symbol found in the forwarders_ map of
1039 // Symbol_table (bit 20).
1040 bool is_forwarder_ : 1;
1041 // True if the symbol has an alias in the weak_aliases table in
1042 // Symbol_table (bit 21).
1043 bool has_alias_ : 1;
1044 // True if this symbol needs to be in the dynamic symbol table (bit
1046 bool needs_dynsym_entry_ : 1;
1047 // True if we've seen this symbol in a regular object (bit 23).
1049 // True if we've seen this symbol in a dynamic object (bit 24).
1051 // True if this is a dynamic symbol which needs a special value in
1052 // the dynamic symbol table (bit 25).
1053 bool needs_dynsym_value_ : 1;
1054 // True if there is a warning for this symbol (bit 26).
1055 bool has_warning_ : 1;
1056 // True if we are using a COPY reloc for this symbol, so that the
1057 // real definition lives in a dynamic object (bit 27).
1058 bool is_copied_from_dynobj_ : 1;
1059 // True if this symbol was forced to local visibility by a version
1061 bool is_forced_local_ : 1;
1062 // True if the field u_.from_object.shndx is an ordinary section
1063 // index, not one of the special codes from SHN_LORESERVE to
1064 // SHN_HIRESERVE (bit 29).
1065 bool is_ordinary_shndx_ : 1;
1066 // True if we've seen this symbol in a "real" ELF object (bit 30).
1067 // If the symbol has been seen in a relocatable, non-IR, object file,
1068 // it's known to be referenced from outside the IR. A reference from
1069 // a dynamic object doesn't count as a "real" ELF, and we'll simply
1070 // mark the symbol as "visible" from outside the IR. The compiler
1071 // can use this distinction to guide its handling of COMDAT symbols.
1072 bool in_real_elf_ : 1;
1073 // True if this symbol is defined in a section which was discarded
1075 bool is_defined_in_discarded_section_ : 1;
1076 // True if UNDEF_BINDING_WEAK_ has been set (bit 32).
1077 bool undef_binding_set_ : 1;
1078 // True if this symbol was a weak undef resolved by a dynamic def
1079 // or by a special symbol (bit 33).
1080 bool undef_binding_weak_ : 1;
1081 // True if this symbol is a predefined linker symbol (bit 34).
1082 bool is_predefined_ : 1;
1083 // True if this symbol has protected visibility in a shared object (bit 35).
1084 // The visibility_ field will be STV_DEFAULT in this case because we
1085 // must treat it as such from outside the shared object.
1086 bool is_protected_ : 1;
1089 // The parts of a symbol which are size specific. Using a template
1090 // derived class like this helps us use less space on a 32-bit system.
1093 class Sized_symbol : public Symbol
1096 typedef typename elfcpp::Elf_types<size>::Elf_Addr Value_type;
1097 typedef typename elfcpp::Elf_types<size>::Elf_WXword Size_type;
1102 // Initialize fields from an ELF symbol in OBJECT. ST_SHNDX is the
1103 // section index, IS_ORDINARY is whether it is a normal section
1104 // index rather than a special code.
1105 template<bool big_endian>
1107 init_object(const char* name, const char* version, Object* object,
1108 const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
1111 // Initialize fields for an Output_data.
1113 init_output_data(const char* name, const char* version, Output_data*,
1114 Value_type value, Size_type symsize, elfcpp::STT,
1115 elfcpp::STB, elfcpp::STV, unsigned char nonvis,
1116 bool offset_is_from_end, bool is_predefined);
1118 // Initialize fields for an Output_segment.
1120 init_output_segment(const char* name, const char* version, Output_segment*,
1121 Value_type value, Size_type symsize, elfcpp::STT,
1122 elfcpp::STB, elfcpp::STV, unsigned char nonvis,
1123 Segment_offset_base offset_base, bool is_predefined);
1125 // Initialize fields for a constant.
1127 init_constant(const char* name, const char* version, Value_type value,
1128 Size_type symsize, elfcpp::STT, elfcpp::STB, elfcpp::STV,
1129 unsigned char nonvis, bool is_predefined);
1131 // Initialize fields for an undefined symbol.
1133 init_undefined(const char* name, const char* version, Value_type value,
1134 elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis);
1136 // Override existing symbol.
1137 template<bool big_endian>
1139 override(const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
1140 bool is_ordinary, Object* object, const char* version);
1142 // Override existing symbol with a special symbol.
1144 override_with_special(const Sized_symbol<size>*);
1146 // Return the symbol's value.
1149 { return this->value_; }
1151 // Return the symbol's size (we can't call this 'size' because that
1152 // is a template parameter).
1155 { return this->symsize_; }
1157 // Set the symbol size. This is used when resolving common symbols.
1159 set_symsize(Size_type symsize)
1160 { this->symsize_ = symsize; }
1162 // Set the symbol value. This is called when we store the final
1163 // values of the symbols into the symbol table.
1165 set_value(Value_type value)
1166 { this->value_ = value; }
1168 // Allocate a common symbol by giving it a location in the output
1171 allocate_common(Output_data*, Value_type value);
1174 Sized_symbol(const Sized_symbol&);
1175 Sized_symbol& operator=(const Sized_symbol&);
1177 // Symbol value. Before Layout::finalize this is the offset in the
1178 // input section. This is set to the final value during
1179 // Layout::finalize.
1185 // A struct describing a symbol defined by the linker, where the value
1186 // of the symbol is defined based on an output section. This is used
1187 // for symbols defined by the linker, like "_init_array_start".
1189 struct Define_symbol_in_section
1193 // The name of the output section with which this symbol should be
1194 // associated. If there is no output section with that name, the
1195 // symbol will be defined as zero.
1196 const char* output_section;
1197 // The offset of the symbol within the output section. This is an
1198 // offset from the start of the output section, unless start_at_end
1199 // is true, in which case this is an offset from the end of the
1202 // The size of the symbol.
1206 // The symbol binding.
1207 elfcpp::STB binding;
1208 // The symbol visibility.
1209 elfcpp::STV visibility;
1210 // The rest of the st_other field.
1211 unsigned char nonvis;
1212 // If true, the value field is an offset from the end of the output
1214 bool offset_is_from_end;
1215 // If true, this symbol is defined only if we see a reference to it.
1219 // A struct describing a symbol defined by the linker, where the value
1220 // of the symbol is defined based on a segment. This is used for
1221 // symbols defined by the linker, like "_end". We describe the
1222 // segment with which the symbol should be associated by its
1223 // characteristics. If no segment meets these characteristics, the
1224 // symbol will be defined as zero. If there is more than one segment
1225 // which meets these characteristics, we will use the first one.
1227 struct Define_symbol_in_segment
1231 // The segment type where the symbol should be defined, typically
1233 elfcpp::PT segment_type;
1234 // Bitmask of segment flags which must be set.
1235 elfcpp::PF segment_flags_set;
1236 // Bitmask of segment flags which must be clear.
1237 elfcpp::PF segment_flags_clear;
1238 // The offset of the symbol within the segment. The offset is
1239 // calculated from the position set by offset_base.
1241 // The size of the symbol.
1245 // The symbol binding.
1246 elfcpp::STB binding;
1247 // The symbol visibility.
1248 elfcpp::STV visibility;
1249 // The rest of the st_other field.
1250 unsigned char nonvis;
1251 // The base from which we compute the offset.
1252 Symbol::Segment_offset_base offset_base;
1253 // If true, this symbol is defined only if we see a reference to it.
1257 // Specify an object/section/offset location. Used by ODR code.
1259 struct Symbol_location
1261 // Object where the symbol is defined.
1263 // Section-in-object where the symbol is defined.
1265 // For relocatable objects, offset-in-section where the symbol is defined.
1266 // For dynamic objects, address where the symbol is defined.
1268 bool operator==(const Symbol_location& that) const
1270 return (this->object == that.object
1271 && this->shndx == that.shndx
1272 && this->offset == that.offset);
1276 // A map from symbol name (as a pointer into the namepool) to all
1277 // the locations the symbols is (weakly) defined (and certain other
1278 // conditions are met). This map will be used later to detect
1279 // possible One Definition Rule (ODR) violations.
1280 struct Symbol_location_hash
1282 size_t operator()(const Symbol_location& loc) const
1283 { return reinterpret_cast<uintptr_t>(loc.object) ^ loc.offset ^ loc.shndx; }
1286 // This class manages warnings. Warnings are a GNU extension. When
1287 // we see a section named .gnu.warning.SYM in an object file, and if
1288 // we wind using the definition of SYM from that object file, then we
1289 // will issue a warning for any relocation against SYM from a
1290 // different object file. The text of the warning is the contents of
1291 // the section. This is not precisely the definition used by the old
1292 // GNU linker; the old GNU linker treated an occurrence of
1293 // .gnu.warning.SYM as defining a warning symbol. A warning symbol
1294 // would trigger a warning on any reference. However, it was
1295 // inconsistent in that a warning in a dynamic object only triggered
1296 // if there was no definition in a regular object. This linker is
1297 // different in that we only issue a warning if we use the symbol
1298 // definition from the same object file as the warning section.
1307 // Add a warning for symbol NAME in object OBJ. WARNING is the text
1310 add_warning(Symbol_table* symtab, const char* name, Object* obj,
1311 const std::string& warning);
1313 // For each symbol for which we should give a warning, make a note
1316 note_warnings(Symbol_table* symtab);
1318 // Issue a warning for a reference to SYM at RELINFO's location.
1319 template<int size, bool big_endian>
1321 issue_warning(const Symbol* sym, const Relocate_info<size, big_endian>*,
1322 size_t relnum, off_t reloffset) const;
1325 Warnings(const Warnings&);
1326 Warnings& operator=(const Warnings&);
1328 // What we need to know to get the warning text.
1329 struct Warning_location
1331 // The object the warning is in.
1333 // The warning text.
1337 : object(NULL), text()
1341 set(Object* o, const std::string& t)
1348 // A mapping from warning symbol names (canonicalized in
1349 // Symbol_table's namepool_ field) to warning information.
1350 typedef Unordered_map<const char*, Warning_location> Warning_table;
1352 Warning_table warnings_;
1355 // The main linker symbol table.
1360 // The different places where a symbol definition can come from.
1363 // Defined in an object file--the normal case.
1365 // Defined for a COPY reloc.
1367 // Defined on the command line using --defsym.
1369 // Defined (so to speak) on the command line using -u.
1371 // Defined in a linker script.
1373 // Predefined by the linker.
1375 // Defined by the linker during an incremental base link, but not
1376 // a predefined symbol (e.g., common, defined in script).
1380 // The order in which we sort common symbols.
1381 enum Sort_commons_order
1383 SORT_COMMONS_BY_SIZE_DESCENDING,
1384 SORT_COMMONS_BY_ALIGNMENT_DESCENDING,
1385 SORT_COMMONS_BY_ALIGNMENT_ASCENDING
1388 // COUNT is an estimate of how many symbols will be inserted in the
1389 // symbol table. It's ok to put 0 if you don't know; a correct
1390 // guess will just save some CPU by reducing hashtable resizes.
1391 Symbol_table(unsigned int count, const Version_script_info& version_script);
1397 { this->icf_ = icf;}
1401 { return this->icf_; }
1403 // Returns true if ICF determined that this is a duplicate section.
1405 is_section_folded(Relobj* obj, unsigned int shndx) const;
1408 set_gc(Garbage_collection* gc)
1413 { return this->gc_; }
1415 // During garbage collection, this keeps undefined symbols.
1417 gc_mark_undef_symbols(Layout*);
1419 // This tells garbage collection that this symbol is referenced.
1421 gc_mark_symbol(Symbol* sym);
1423 // During garbage collection, this keeps sections that correspond to
1424 // symbols seen in dynamic objects.
1426 gc_mark_dyn_syms(Symbol* sym);
1428 // Add COUNT external symbols from the relocatable object RELOBJ to
1429 // the symbol table. SYMS is the symbols, SYMNDX_OFFSET is the
1430 // offset in the symbol table of the first symbol, SYM_NAMES is
1431 // their names, SYM_NAME_SIZE is the size of SYM_NAMES. This sets
1432 // SYMPOINTERS to point to the symbols in the symbol table. It sets
1433 // *DEFINED to the number of defined symbols.
1434 template<int size, bool big_endian>
1436 add_from_relobj(Sized_relobj_file<size, big_endian>* relobj,
1437 const unsigned char* syms, size_t count,
1438 size_t symndx_offset, const char* sym_names,
1439 size_t sym_name_size,
1440 typename Sized_relobj_file<size, big_endian>::Symbols*,
1443 // Add one external symbol from the plugin object OBJ to the symbol table.
1444 // Returns a pointer to the resolved symbol in the symbol table.
1445 template<int size, bool big_endian>
1447 add_from_pluginobj(Sized_pluginobj<size, big_endian>* obj,
1448 const char* name, const char* ver,
1449 elfcpp::Sym<size, big_endian>* sym);
1451 // Add COUNT dynamic symbols from the dynamic object DYNOBJ to the
1452 // symbol table. SYMS is the symbols. SYM_NAMES is their names.
1453 // SYM_NAME_SIZE is the size of SYM_NAMES. The other parameters are
1454 // symbol version data.
1455 template<int size, bool big_endian>
1457 add_from_dynobj(Sized_dynobj<size, big_endian>* dynobj,
1458 const unsigned char* syms, size_t count,
1459 const char* sym_names, size_t sym_name_size,
1460 const unsigned char* versym, size_t versym_size,
1461 const std::vector<const char*>*,
1462 typename Sized_relobj_file<size, big_endian>::Symbols*,
1465 // Add one external symbol from the incremental object OBJ to the symbol
1466 // table. Returns a pointer to the resolved symbol in the symbol table.
1467 template<int size, bool big_endian>
1469 add_from_incrobj(Object* obj, const char* name,
1470 const char* ver, elfcpp::Sym<size, big_endian>* sym);
1472 // Define a special symbol based on an Output_data. It is a
1473 // multiple definition error if this symbol is already defined.
1475 define_in_output_data(const char* name, const char* version, Defined,
1476 Output_data*, uint64_t value, uint64_t symsize,
1477 elfcpp::STT type, elfcpp::STB binding,
1478 elfcpp::STV visibility, unsigned char nonvis,
1479 bool offset_is_from_end, bool only_if_ref);
1481 // Define a special symbol based on an Output_segment. It is a
1482 // multiple definition error if this symbol is already defined.
1484 define_in_output_segment(const char* name, const char* version, Defined,
1485 Output_segment*, uint64_t value, uint64_t symsize,
1486 elfcpp::STT type, elfcpp::STB binding,
1487 elfcpp::STV visibility, unsigned char nonvis,
1488 Symbol::Segment_offset_base, bool only_if_ref);
1490 // Define a special symbol with a constant value. It is a multiple
1491 // definition error if this symbol is already defined.
1493 define_as_constant(const char* name, const char* version, Defined,
1494 uint64_t value, uint64_t symsize, elfcpp::STT type,
1495 elfcpp::STB binding, elfcpp::STV visibility,
1496 unsigned char nonvis, bool only_if_ref,
1497 bool force_override);
1499 // Define a set of symbols in output sections. If ONLY_IF_REF is
1500 // true, only define them if they are referenced.
1502 define_symbols(const Layout*, int count, const Define_symbol_in_section*,
1505 // Define a set of symbols in output segments. If ONLY_IF_REF is
1506 // true, only defined them if they are referenced.
1508 define_symbols(const Layout*, int count, const Define_symbol_in_segment*,
1511 // Add a target-specific global symbol.
1512 // (Used by SPARC backend to add STT_SPARC_REGISTER symbols.)
1514 add_target_global_symbol(Symbol* sym)
1515 { this->target_symbols_.push_back(sym); }
1517 // Define SYM using a COPY reloc. POSD is the Output_data where the
1518 // symbol should be defined--typically a .dyn.bss section. VALUE is
1519 // the offset within POSD.
1522 define_with_copy_reloc(Sized_symbol<size>* sym, Output_data* posd,
1523 typename elfcpp::Elf_types<size>::Elf_Addr);
1525 // Look up a symbol.
1527 lookup(const char*, const char* version = NULL) const;
1529 // Return the real symbol associated with the forwarder symbol FROM.
1531 resolve_forwards(const Symbol* from) const;
1533 // Return the sized version of a symbol in this table.
1536 get_sized_symbol(Symbol*) const;
1539 const Sized_symbol<size>*
1540 get_sized_symbol(const Symbol*) const;
1542 // Return the count of undefined symbols seen.
1544 saw_undefined() const
1545 { return this->saw_undefined_; }
1547 // Allocate the common symbols
1549 allocate_commons(Layout*, Mapfile*);
1551 // Add a warning for symbol NAME in object OBJ. WARNING is the text
1554 add_warning(const char* name, Object* obj, const std::string& warning)
1555 { this->warnings_.add_warning(this, name, obj, warning); }
1557 // Canonicalize a symbol name for use in the hash table.
1559 canonicalize_name(const char* name)
1560 { return this->namepool_.add(name, true, NULL); }
1562 // Possibly issue a warning for a reference to SYM at LOCATION which
1564 template<int size, bool big_endian>
1566 issue_warning(const Symbol* sym,
1567 const Relocate_info<size, big_endian>* relinfo,
1568 size_t relnum, off_t reloffset) const
1569 { this->warnings_.issue_warning(sym, relinfo, relnum, reloffset); }
1571 // Check candidate_odr_violations_ to find symbols with the same name
1572 // but apparently different definitions (different source-file/line-no).
1574 detect_odr_violations(const Task*, const char* output_file_name) const;
1576 // Add any undefined symbols named on the command line to the symbol
1579 add_undefined_symbols_from_command_line(Layout*);
1581 // SYM is defined using a COPY reloc. Return the dynamic object
1582 // where the original definition was found.
1584 get_copy_source(const Symbol* sym) const;
1586 // Set the dynamic symbol indexes. INDEX is the index of the first
1587 // global dynamic symbol. Return the count of forced-local symbols in
1588 // *PFORCED_LOCAL_COUNT. Pointers to the symbols are stored into
1589 // the vector. The names are stored into the Stringpool. This
1590 // returns an updated dynamic symbol index.
1592 set_dynsym_indexes(unsigned int index, unsigned int* pforced_local_count,
1593 std::vector<Symbol*>*, Stringpool*, Versions*);
1595 // Finalize the symbol table after we have set the final addresses
1596 // of all the input sections. This sets the final symbol indexes,
1597 // values and adds the names to *POOL. *PLOCAL_SYMCOUNT is the
1598 // index of the first global symbol. OFF is the file offset of the
1599 // global symbol table, DYNOFF is the offset of the globals in the
1600 // dynamic symbol table, DYN_GLOBAL_INDEX is the index of the first
1601 // global dynamic symbol, and DYNCOUNT is the number of global
1602 // dynamic symbols. This records the parameters, and returns the
1603 // new file offset. It updates *PLOCAL_SYMCOUNT if it created any
1606 finalize(off_t off, off_t dynoff, size_t dyn_global_index, size_t dyncount,
1607 Stringpool* pool, unsigned int* plocal_symcount);
1609 // Set the final file offset of the symbol table.
1611 set_file_offset(off_t off)
1612 { this->offset_ = off; }
1614 // Status code of Symbol_table::compute_final_value.
1615 enum Compute_final_value_status
1619 // Unsupported symbol section.
1620 CFVS_UNSUPPORTED_SYMBOL_SECTION,
1621 // No output section.
1622 CFVS_NO_OUTPUT_SECTION
1625 // Compute the final value of SYM and store status in location PSTATUS.
1626 // During relaxation, this may be called multiple times for a symbol to
1627 // compute its would-be final value in each relaxation pass.
1630 typename Sized_symbol<size>::Value_type
1631 compute_final_value(const Sized_symbol<size>* sym,
1632 Compute_final_value_status* pstatus) const;
1634 // Return the index of the first global symbol.
1636 first_global_index() const
1637 { return this->first_global_index_; }
1639 // Return the total number of symbols in the symbol table.
1641 output_count() const
1642 { return this->output_count_; }
1644 // Write out the global symbols.
1646 write_globals(const Stringpool*, const Stringpool*,
1647 Output_symtab_xindex*, Output_symtab_xindex*,
1648 Output_file*) const;
1650 // Write out a section symbol. Return the updated offset.
1652 write_section_symbol(const Output_section*, Output_symtab_xindex*,
1653 Output_file*, off_t) const;
1655 // Loop over all symbols, applying the function F to each.
1656 template<int size, typename F>
1658 for_all_symbols(F f) const
1660 for (Symbol_table_type::const_iterator p = this->table_.begin();
1661 p != this->table_.end();
1664 Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second);
1669 // Dump statistical information to stderr.
1671 print_stats() const;
1673 // Return the version script information.
1674 const Version_script_info&
1675 version_script() const
1676 { return version_script_; }
1679 Symbol_table(const Symbol_table&);
1680 Symbol_table& operator=(const Symbol_table&);
1682 // The type of the list of common symbols.
1683 typedef std::vector<Symbol*> Commons_type;
1685 // The type of the symbol hash table.
1687 typedef std::pair<Stringpool::Key, Stringpool::Key> Symbol_table_key;
1689 // The hash function. The key values are Stringpool keys.
1690 struct Symbol_table_hash
1693 operator()(const Symbol_table_key& key) const
1695 return key.first ^ key.second;
1699 struct Symbol_table_eq
1702 operator()(const Symbol_table_key&, const Symbol_table_key&) const;
1705 typedef Unordered_map<Symbol_table_key, Symbol*, Symbol_table_hash,
1706 Symbol_table_eq> Symbol_table_type;
1708 typedef Unordered_map<const char*,
1709 Unordered_set<Symbol_location, Symbol_location_hash> >
1712 // Make FROM a forwarder symbol to TO.
1714 make_forwarder(Symbol* from, Symbol* to);
1717 template<int size, bool big_endian>
1719 add_from_object(Object*, const char* name, Stringpool::Key name_key,
1720 const char* version, Stringpool::Key version_key,
1721 bool def, const elfcpp::Sym<size, big_endian>& sym,
1722 unsigned int st_shndx, bool is_ordinary,
1723 unsigned int orig_st_shndx);
1725 // Define a default symbol.
1726 template<int size, bool big_endian>
1728 define_default_version(Sized_symbol<size>*, bool,
1729 Symbol_table_type::iterator);
1732 template<int size, bool big_endian>
1734 resolve(Sized_symbol<size>* to,
1735 const elfcpp::Sym<size, big_endian>& sym,
1736 unsigned int st_shndx, bool is_ordinary,
1737 unsigned int orig_st_shndx,
1738 Object*, const char* version,
1739 bool is_default_version);
1741 template<int size, bool big_endian>
1743 resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from);
1745 // Record that a symbol is forced to be local by a version script or
1748 force_local(Symbol*);
1750 // Adjust NAME and *NAME_KEY for wrapping.
1752 wrap_symbol(const char* name, Stringpool::Key* name_key);
1754 // Whether we should override a symbol, based on flags in
1757 should_override(const Symbol*, unsigned int, elfcpp::STT, Defined,
1758 Object*, bool*, bool*, bool);
1760 // Report a problem in symbol resolution.
1762 report_resolve_problem(bool is_error, const char* msg, const Symbol* to,
1763 Defined, Object* object);
1765 // Override a symbol.
1766 template<int size, bool big_endian>
1768 override(Sized_symbol<size>* tosym,
1769 const elfcpp::Sym<size, big_endian>& fromsym,
1770 unsigned int st_shndx, bool is_ordinary,
1771 Object* object, const char* version);
1773 // Whether we should override a symbol with a special symbol which
1774 // is automatically defined by the linker.
1776 should_override_with_special(const Symbol*, elfcpp::STT, Defined);
1778 // Override a symbol with a special symbol.
1781 override_with_special(Sized_symbol<size>* tosym,
1782 const Sized_symbol<size>* fromsym);
1784 // Record all weak alias sets for a dynamic object.
1787 record_weak_aliases(std::vector<Sized_symbol<size>*>*);
1789 // Define a special symbol.
1790 template<int size, bool big_endian>
1792 define_special_symbol(const char** pname, const char** pversion,
1793 bool only_if_ref, Sized_symbol<size>** poldsym,
1794 bool* resolve_oldsym, bool is_forced_local);
1796 // Define a symbol in an Output_data, sized version.
1799 do_define_in_output_data(const char* name, const char* version, Defined,
1801 typename elfcpp::Elf_types<size>::Elf_Addr value,
1802 typename elfcpp::Elf_types<size>::Elf_WXword ssize,
1803 elfcpp::STT type, elfcpp::STB binding,
1804 elfcpp::STV visibility, unsigned char nonvis,
1805 bool offset_is_from_end, bool only_if_ref);
1807 // Define a symbol in an Output_segment, sized version.
1810 do_define_in_output_segment(
1811 const char* name, const char* version, Defined, Output_segment* os,
1812 typename elfcpp::Elf_types<size>::Elf_Addr value,
1813 typename elfcpp::Elf_types<size>::Elf_WXword ssize,
1814 elfcpp::STT type, elfcpp::STB binding,
1815 elfcpp::STV visibility, unsigned char nonvis,
1816 Symbol::Segment_offset_base offset_base, bool only_if_ref);
1818 // Define a symbol as a constant, sized version.
1821 do_define_as_constant(
1822 const char* name, const char* version, Defined,
1823 typename elfcpp::Elf_types<size>::Elf_Addr value,
1824 typename elfcpp::Elf_types<size>::Elf_WXword ssize,
1825 elfcpp::STT type, elfcpp::STB binding,
1826 elfcpp::STV visibility, unsigned char nonvis,
1827 bool only_if_ref, bool force_override);
1829 // Add any undefined symbols named on the command line to the symbol
1830 // table, sized version.
1833 do_add_undefined_symbols_from_command_line(Layout*);
1835 // Add one undefined symbol.
1838 add_undefined_symbol_from_command_line(const char* name);
1840 // Types of common symbols.
1842 enum Commons_section_type
1850 // Allocate the common symbols, sized version.
1853 do_allocate_commons(Layout*, Mapfile*, Sort_commons_order);
1855 // Allocate the common symbols from one list.
1858 do_allocate_commons_list(Layout*, Commons_section_type, Commons_type*,
1859 Mapfile*, Sort_commons_order);
1861 // Returns all of the lines attached to LOC, not just the one the
1862 // instruction actually came from. This helps the ODR checker avoid
1864 static std::vector<std::string>
1865 linenos_from_loc(const Task* task, const Symbol_location& loc);
1867 // Implement detect_odr_violations.
1868 template<int size, bool big_endian>
1870 sized_detect_odr_violations() const;
1872 // Finalize symbols specialized for size.
1875 sized_finalize(off_t, Stringpool*, unsigned int*);
1877 // Finalize a symbol. Return whether it should be added to the
1881 sized_finalize_symbol(Symbol*);
1883 // Add a symbol the final symtab by setting its index.
1886 add_to_final_symtab(Symbol*, Stringpool*, unsigned int* pindex, off_t* poff);
1888 // Write globals specialized for size and endianness.
1889 template<int size, bool big_endian>
1891 sized_write_globals(const Stringpool*, const Stringpool*,
1892 Output_symtab_xindex*, Output_symtab_xindex*,
1893 Output_file*) const;
1895 // Write out a symbol to P.
1896 template<int size, bool big_endian>
1898 sized_write_symbol(Sized_symbol<size>*,
1899 typename elfcpp::Elf_types<size>::Elf_Addr value,
1900 unsigned int shndx, elfcpp::STB,
1901 const Stringpool*, unsigned char* p) const;
1903 // Possibly warn about an undefined symbol from a dynamic object.
1905 warn_about_undefined_dynobj_symbol(Symbol*) const;
1907 // Write out a section symbol, specialized for size and endianness.
1908 template<int size, bool big_endian>
1910 sized_write_section_symbol(const Output_section*, Output_symtab_xindex*,
1911 Output_file*, off_t) const;
1913 // The type of the list of symbols which have been forced local.
1914 typedef std::vector<Symbol*> Forced_locals;
1916 // A map from symbols with COPY relocs to the dynamic objects where
1917 // they are defined.
1918 typedef Unordered_map<const Symbol*, Dynobj*> Copied_symbol_dynobjs;
1920 // We increment this every time we see a new undefined symbol, for
1921 // use in archive groups.
1922 size_t saw_undefined_;
1923 // The index of the first global symbol in the output file.
1924 unsigned int first_global_index_;
1925 // The file offset within the output symtab section where we should
1928 // The number of global symbols we want to write out.
1929 unsigned int output_count_;
1930 // The file offset of the global dynamic symbols, or 0 if none.
1931 off_t dynamic_offset_;
1932 // The index of the first global dynamic symbol (including
1933 // forced-local symbols).
1934 unsigned int first_dynamic_global_index_;
1935 // The number of global dynamic symbols (including forced-local symbols),
1937 unsigned int dynamic_count_;
1938 // The symbol hash table.
1939 Symbol_table_type table_;
1940 // A pool of symbol names. This is used for all global symbols.
1941 // Entries in the hash table point into this pool.
1942 Stringpool namepool_;
1943 // Forwarding symbols.
1944 Unordered_map<const Symbol*, Symbol*> forwarders_;
1945 // Weak aliases. A symbol in this list points to the next alias.
1946 // The aliases point to each other in a circular list.
1947 Unordered_map<Symbol*, Symbol*> weak_aliases_;
1948 // We don't expect there to be very many common symbols, so we keep
1949 // a list of them. When we find a common symbol we add it to this
1950 // list. It is possible that by the time we process the list the
1951 // symbol is no longer a common symbol. It may also have become a
1953 Commons_type commons_;
1954 // This is like the commons_ field, except that it holds TLS common
1956 Commons_type tls_commons_;
1957 // This is for small common symbols.
1958 Commons_type small_commons_;
1959 // This is for large common symbols.
1960 Commons_type large_commons_;
1961 // A list of symbols which have been forced to be local. We don't
1962 // expect there to be very many of them, so we keep a list of them
1963 // rather than walking the whole table to find them.
1964 Forced_locals forced_locals_;
1965 // Manage symbol warnings.
1967 // Manage potential One Definition Rule (ODR) violations.
1968 Odr_map candidate_odr_violations_;
1970 // When we emit a COPY reloc for a symbol, we define it in an
1971 // Output_data. When it's time to emit version information for it,
1972 // we need to know the dynamic object in which we found the original
1973 // definition. This maps symbols with COPY relocs to the dynamic
1974 // object where they were defined.
1975 Copied_symbol_dynobjs copied_symbol_dynobjs_;
1976 // Information parsed from the version script, if any.
1977 const Version_script_info& version_script_;
1978 Garbage_collection* gc_;
1980 // Target-specific symbols, if any.
1981 std::vector<Symbol*> target_symbols_;
1984 // We inline get_sized_symbol for efficiency.
1988 Symbol_table::get_sized_symbol(Symbol* sym) const
1990 gold_assert(size == parameters->target().get_size());
1991 return static_cast<Sized_symbol<size>*>(sym);
1995 const Sized_symbol<size>*
1996 Symbol_table::get_sized_symbol(const Symbol* sym) const
1998 gold_assert(size == parameters->target().get_size());
1999 return static_cast<const Sized_symbol<size>*>(sym);
2002 } // End namespace gold.
2004 #endif // !defined(GOLD_SYMTAB_H)