1 // symtab.h -- the gold symbol table -*- C++ -*-
3 // Copyright (C) 2006-2014 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 // Return the symbol's name as name@version (or name@@version).
145 versioned_name() const;
147 // Return the symbol source.
150 { return this->source_
; }
152 // Return the object with which this symbol is associated.
156 gold_assert(this->source_
== FROM_OBJECT
);
157 return this->u_
.from_object
.object
;
160 // Return the index of the section in the input relocatable or
161 // dynamic object file.
163 shndx(bool* is_ordinary
) const
165 gold_assert(this->source_
== FROM_OBJECT
);
166 *is_ordinary
= this->is_ordinary_shndx_
;
167 return this->u_
.from_object
.shndx
;
170 // Return the output data section with which this symbol is
171 // associated, if the symbol was specially defined with respect to
172 // an output data section.
176 gold_assert(this->source_
== IN_OUTPUT_DATA
);
177 return this->u_
.in_output_data
.output_data
;
180 // If this symbol was defined with respect to an output data
181 // section, return whether the value is an offset from end.
183 offset_is_from_end() const
185 gold_assert(this->source_
== IN_OUTPUT_DATA
);
186 return this->u_
.in_output_data
.offset_is_from_end
;
189 // Return the output segment with which this symbol is associated,
190 // if the symbol was specially defined with respect to an output
193 output_segment() const
195 gold_assert(this->source_
== IN_OUTPUT_SEGMENT
);
196 return this->u_
.in_output_segment
.output_segment
;
199 // If this symbol was defined with respect to an output segment,
200 // return the offset base.
204 gold_assert(this->source_
== IN_OUTPUT_SEGMENT
);
205 return this->u_
.in_output_segment
.offset_base
;
208 // Return the symbol binding.
211 { return this->binding_
; }
213 // Return the symbol type.
216 { return this->type_
; }
218 // Return true for function symbol.
222 return (this->type_
== elfcpp::STT_FUNC
223 || this->type_
== elfcpp::STT_GNU_IFUNC
);
226 // Return the symbol visibility.
229 { return this->visibility_
; }
231 // Set the visibility.
233 set_visibility(elfcpp::STV visibility
)
234 { this->visibility_
= visibility
; }
236 // Override symbol visibility.
238 override_visibility(elfcpp::STV
);
240 // Set whether the symbol was originally a weak undef or a regular undef
241 // when resolved by a dynamic def or by a special symbol.
243 set_undef_binding(elfcpp::STB bind
)
245 if (!this->undef_binding_set_
|| this->undef_binding_weak_
)
247 this->undef_binding_weak_
= bind
== elfcpp::STB_WEAK
;
248 this->undef_binding_set_
= true;
252 // Return TRUE if a weak undef was resolved by a dynamic def or
253 // by a special symbol.
255 is_undef_binding_weak() const
256 { return this->undef_binding_weak_
; }
258 // Return the non-visibility part of the st_other field.
261 { return this->nonvis_
; }
263 // Set the non-visibility part of the st_other field.
265 set_nonvis(unsigned int nonvis
)
266 { this->nonvis_
= nonvis
; }
268 // Return whether this symbol is a forwarder. This will never be
269 // true of a symbol found in the hash table, but may be true of
270 // symbol pointers attached to object files.
273 { return this->is_forwarder_
; }
275 // Mark this symbol as a forwarder.
278 { this->is_forwarder_
= true; }
280 // Return whether this symbol has an alias in the weak aliases table
284 { return this->has_alias_
; }
286 // Mark this symbol as having an alias.
289 { this->has_alias_
= true; }
291 // Return whether this symbol needs an entry in the dynamic symbol
294 needs_dynsym_entry() const
296 return (this->needs_dynsym_entry_
299 && this->is_externally_visible()));
302 // Mark this symbol as needing an entry in the dynamic symbol table.
304 set_needs_dynsym_entry()
305 { this->needs_dynsym_entry_
= true; }
307 // Return whether this symbol should be added to the dynamic symbol
310 should_add_dynsym_entry(Symbol_table
*) const;
312 // Return whether this symbol has been seen in a regular object.
315 { return this->in_reg_
; }
317 // Mark this symbol as having been seen in a regular object.
320 { this->in_reg_
= true; }
322 // Return whether this symbol has been seen in a dynamic object.
325 { return this->in_dyn_
; }
327 // Mark this symbol as having been seen in a dynamic object.
330 { this->in_dyn_
= true; }
332 // Return whether this symbol has been seen in a real ELF object.
333 // (IN_REG will return TRUE if the symbol has been seen in either
334 // a real ELF object or an object claimed by a plugin.)
337 { return this->in_real_elf_
; }
339 // Mark this symbol as having been seen in a real ELF object.
342 { this->in_real_elf_
= true; }
344 // Return whether this symbol was defined in a section that was
345 // discarded from the link. This is used to control some error
348 is_defined_in_discarded_section() const
349 { return this->is_defined_in_discarded_section_
; }
351 // Mark this symbol as having been defined in a discarded section.
353 set_is_defined_in_discarded_section()
354 { this->is_defined_in_discarded_section_
= true; }
356 // Return the index of this symbol in the output file symbol table.
357 // A value of -1U means that this symbol is not going into the
358 // output file. This starts out as zero, and is set to a non-zero
359 // value by Symbol_table::finalize. It is an error to ask for the
360 // symbol table index before it has been set.
364 gold_assert(this->symtab_index_
!= 0);
365 return this->symtab_index_
;
368 // Set the index of the symbol in the output file symbol table.
370 set_symtab_index(unsigned int index
)
372 gold_assert(index
!= 0);
373 this->symtab_index_
= index
;
376 // Return whether this symbol already has an index in the output
377 // file symbol table.
379 has_symtab_index() const
380 { return this->symtab_index_
!= 0; }
382 // Return the index of this symbol in the dynamic symbol table. A
383 // value of -1U means that this symbol is not going into the dynamic
384 // symbol table. This starts out as zero, and is set to a non-zero
385 // during Layout::finalize. It is an error to ask for the dynamic
386 // symbol table index before it has been set.
390 gold_assert(this->dynsym_index_
!= 0);
391 return this->dynsym_index_
;
394 // Set the index of the symbol in the dynamic symbol table.
396 set_dynsym_index(unsigned int index
)
398 gold_assert(index
!= 0);
399 this->dynsym_index_
= index
;
402 // Return whether this symbol already has an index in the dynamic
405 has_dynsym_index() const
406 { return this->dynsym_index_
!= 0; }
408 // Return whether this symbol has an entry in the GOT section.
409 // For a TLS symbol, this GOT entry will hold its tp-relative offset.
411 has_got_offset(unsigned int got_type
) const
412 { return this->got_offsets_
.get_offset(got_type
) != -1U; }
414 // Return the offset into the GOT section of this symbol.
416 got_offset(unsigned int got_type
) const
418 unsigned int got_offset
= this->got_offsets_
.get_offset(got_type
);
419 gold_assert(got_offset
!= -1U);
423 // Set the GOT offset of this symbol.
425 set_got_offset(unsigned int got_type
, unsigned int got_offset
)
426 { this->got_offsets_
.set_offset(got_type
, got_offset
); }
428 // Return the GOT offset list.
429 const Got_offset_list
*
430 got_offset_list() const
431 { return this->got_offsets_
.get_list(); }
433 // Return whether this symbol has an entry in the PLT section.
435 has_plt_offset() const
436 { return this->plt_offset_
!= -1U; }
438 // Return the offset into the PLT section of this symbol.
442 gold_assert(this->has_plt_offset());
443 return this->plt_offset_
;
446 // Set the PLT offset of this symbol.
448 set_plt_offset(unsigned int plt_offset
)
450 gold_assert(plt_offset
!= -1U);
451 this->plt_offset_
= plt_offset
;
454 // Return whether this dynamic symbol needs a special value in the
455 // dynamic symbol table.
457 needs_dynsym_value() const
458 { return this->needs_dynsym_value_
; }
460 // Set that this dynamic symbol needs a special value in the dynamic
463 set_needs_dynsym_value()
465 gold_assert(this->object()->is_dynamic());
466 this->needs_dynsym_value_
= true;
469 // Return true if the final value of this symbol is known at link
472 final_value_is_known() const;
474 // Return true if SHNDX represents a common symbol. This depends on
477 is_common_shndx(unsigned int shndx
);
479 // Return whether this is a defined symbol (not undefined or
485 if (this->source_
!= FROM_OBJECT
)
486 return this->source_
!= IS_UNDEFINED
;
487 unsigned int shndx
= this->shndx(&is_ordinary
);
489 ? shndx
!= elfcpp::SHN_UNDEF
490 : !Symbol::is_common_shndx(shndx
));
493 // Return true if this symbol is from a dynamic object.
495 is_from_dynobj() const
497 return this->source_
== FROM_OBJECT
&& this->object()->is_dynamic();
500 // Return whether this is a placeholder symbol from a plugin object.
502 is_placeholder() const
504 return this->source_
== FROM_OBJECT
&& this->object()->pluginobj() != NULL
;
507 // Return whether this is an undefined symbol.
512 return ((this->source_
== FROM_OBJECT
513 && this->shndx(&is_ordinary
) == elfcpp::SHN_UNDEF
515 || this->source_
== IS_UNDEFINED
);
518 // Return whether this is a weak undefined symbol.
520 is_weak_undefined() const
522 return (this->is_undefined()
523 && (this->binding() == elfcpp::STB_WEAK
524 || this->is_undef_binding_weak()));
527 // Return whether this is a strong undefined symbol.
529 is_strong_undefined() const
531 return (this->is_undefined()
532 && this->binding() != elfcpp::STB_WEAK
533 && !this->is_undef_binding_weak());
536 // Return whether this is an absolute symbol.
541 return ((this->source_
== FROM_OBJECT
542 && this->shndx(&is_ordinary
) == elfcpp::SHN_ABS
544 || this->source_
== IS_CONSTANT
);
547 // Return whether this is a common symbol.
551 if (this->source_
!= FROM_OBJECT
)
553 if (this->type_
== elfcpp::STT_COMMON
)
556 unsigned int shndx
= this->shndx(&is_ordinary
);
557 return !is_ordinary
&& Symbol::is_common_shndx(shndx
);
560 // Return whether this symbol can be seen outside this object.
562 is_externally_visible() const
564 return ((this->visibility_
== elfcpp::STV_DEFAULT
565 || this->visibility_
== elfcpp::STV_PROTECTED
)
566 && !this->is_forced_local_
);
569 // Return true if this symbol can be preempted by a definition in
570 // another link unit.
572 is_preemptible() const
574 // It doesn't make sense to ask whether a symbol defined in
575 // another object is preemptible.
576 gold_assert(!this->is_from_dynobj());
578 // It doesn't make sense to ask whether an undefined symbol
580 gold_assert(!this->is_undefined());
582 // If a symbol does not have default visibility, it can not be
583 // seen outside this link unit and therefore is not preemptible.
584 if (this->visibility_
!= elfcpp::STV_DEFAULT
)
587 // If this symbol has been forced to be a local symbol by a
588 // version script, then it is not visible outside this link unit
589 // and is not preemptible.
590 if (this->is_forced_local_
)
593 // If we are not producing a shared library, then nothing is
595 if (!parameters
->options().shared())
598 // If the symbol was named in a --dynamic-list script, it is preemptible.
599 if (parameters
->options().in_dynamic_list(this->name()))
602 // If the user used -Bsymbolic or provided a --dynamic-list script,
603 // then nothing (else) is preemptible.
604 if (parameters
->options().Bsymbolic()
605 || parameters
->options().have_dynamic_list())
608 // If the user used -Bsymbolic-functions, then functions are not
609 // preemptible. We explicitly check for not being STT_OBJECT,
610 // rather than for being STT_FUNC, because that is what the GNU
612 if (this->type() != elfcpp::STT_OBJECT
613 && parameters
->options().Bsymbolic_functions())
616 // Otherwise the symbol is preemptible.
620 // Return true if this symbol is a function that needs a PLT entry.
622 needs_plt_entry() const
624 // An undefined symbol from an executable does not need a PLT entry.
625 if (this->is_undefined() && !parameters
->options().shared())
628 // An STT_GNU_IFUNC symbol always needs a PLT entry, even when
629 // doing a static link.
630 if (this->type() == elfcpp::STT_GNU_IFUNC
)
633 // We only need a PLT entry for a function.
634 if (!this->is_func())
637 // If we're doing a static link or a -pie link, we don't create
639 if (parameters
->doing_static_link()
640 || parameters
->options().pie())
643 // We need a PLT entry if the function is defined in a dynamic
644 // object, or is undefined when building a shared object, or if it
645 // is subject to pre-emption.
646 return (this->is_from_dynobj()
647 || this->is_undefined()
648 || this->is_preemptible());
651 // When determining whether a reference to a symbol needs a dynamic
652 // relocation, we need to know several things about the reference.
653 // These flags may be or'ed together. 0 means that the symbol
654 // isn't referenced at all.
657 // A reference to the symbol's absolute address. This includes
658 // references that cause an absolute address to be stored in the GOT.
660 // A reference that calculates the offset of the symbol from some
661 // anchor point, such as the PC or GOT.
663 // A TLS-related reference.
665 // A reference that can always be treated as a function call.
667 // When set, says that dynamic relocations are needed even if a
668 // symbol has a plt entry.
672 // Given a direct absolute or pc-relative static relocation against
673 // the global symbol, this function returns whether a dynamic relocation
677 needs_dynamic_reloc(int flags
) const
679 // No dynamic relocations in a static link!
680 if (parameters
->doing_static_link())
683 // A reference to an undefined symbol from an executable should be
684 // statically resolved to 0, and does not need a dynamic relocation.
685 // This matches gnu ld behavior.
686 if (this->is_undefined() && !parameters
->options().shared())
689 // A reference to an absolute symbol does not need a dynamic relocation.
690 if (this->is_absolute())
693 // An absolute reference within a position-independent output file
694 // will need a dynamic relocation.
695 if ((flags
& ABSOLUTE_REF
)
696 && parameters
->options().output_is_position_independent())
699 // A function call that can branch to a local PLT entry does not need
700 // a dynamic relocation.
701 if ((flags
& FUNCTION_CALL
) && this->has_plt_offset())
704 // A reference to any PLT entry in a non-position-independent executable
705 // does not need a dynamic relocation.
706 if (!(flags
& FUNC_DESC_ABI
)
707 && !parameters
->options().output_is_position_independent()
708 && this->has_plt_offset())
711 // A reference to a symbol defined in a dynamic object or to a
712 // symbol that is preemptible will need a dynamic relocation.
713 if (this->is_from_dynobj()
714 || this->is_undefined()
715 || this->is_preemptible())
718 // For all other cases, return FALSE.
722 // Whether we should use the PLT offset associated with a symbol for
723 // a relocation. FLAGS is a set of Reference_flags.
726 use_plt_offset(int flags
) const
728 // If the symbol doesn't have a PLT offset, then naturally we
729 // don't want to use it.
730 if (!this->has_plt_offset())
733 // For a STT_GNU_IFUNC symbol we always have to use the PLT entry.
734 if (this->type() == elfcpp::STT_GNU_IFUNC
)
737 // If we are going to generate a dynamic relocation, then we will
738 // wind up using that, so no need to use the PLT entry.
739 if (this->needs_dynamic_reloc(flags
))
742 // If the symbol is from a dynamic object, we need to use the PLT
744 if (this->is_from_dynobj())
747 // If we are generating a shared object, and this symbol is
748 // undefined or preemptible, we need to use the PLT entry.
749 if (parameters
->options().shared()
750 && (this->is_undefined() || this->is_preemptible()))
753 // If this is a call to a weak undefined symbol, we need to use
754 // the PLT entry; the symbol may be defined by a library loaded
756 if ((flags
& FUNCTION_CALL
) && this->is_weak_undefined())
759 // Otherwise we can use the regular definition.
763 // Given a direct absolute static relocation against
764 // the global symbol, where a dynamic relocation is needed, this
765 // function returns whether a relative dynamic relocation can be used.
766 // The caller must determine separately whether the static relocation
767 // is compatible with a relative relocation.
770 can_use_relative_reloc(bool is_function_call
) const
772 // A function call that can branch to a local PLT entry can
773 // use a RELATIVE relocation.
774 if (is_function_call
&& this->has_plt_offset())
777 // A reference to a symbol defined in a dynamic object or to a
778 // symbol that is preemptible can not use a RELATIVE relocation.
779 if (this->is_from_dynobj()
780 || this->is_undefined()
781 || this->is_preemptible())
784 // For all other cases, return TRUE.
788 // Return the output section where this symbol is defined. Return
789 // NULL if the symbol has an absolute value.
791 output_section() const;
793 // Set the symbol's output section. This is used for symbols
794 // defined in scripts. This should only be called after the symbol
795 // table has been finalized.
797 set_output_section(Output_section
*);
799 // Set the symbol's output segment. This is used for pre-defined
800 // symbols whose segments aren't known until after layout is done
801 // (e.g., __ehdr_start).
803 set_output_segment(Output_segment
*, Segment_offset_base
);
805 // Set the symbol to undefined. This is used for pre-defined
806 // symbols whose segments aren't known until after layout is done
807 // (e.g., __ehdr_start).
811 // Return whether there should be a warning for references to this
815 { return this->has_warning_
; }
817 // Mark this symbol as having a warning.
820 { this->has_warning_
= true; }
822 // Return whether this symbol is defined by a COPY reloc from a
825 is_copied_from_dynobj() const
826 { return this->is_copied_from_dynobj_
; }
828 // Mark this symbol as defined by a COPY reloc.
830 set_is_copied_from_dynobj()
831 { this->is_copied_from_dynobj_
= true; }
833 // Return whether this symbol is forced to visibility STB_LOCAL
834 // by a "local:" entry in a version script.
836 is_forced_local() const
837 { return this->is_forced_local_
; }
839 // Mark this symbol as forced to STB_LOCAL visibility.
841 set_is_forced_local()
842 { this->is_forced_local_
= true; }
844 // Return true if this may need a COPY relocation.
845 // References from an executable object to non-function symbols
846 // defined in a dynamic object may need a COPY relocation.
848 may_need_copy_reloc() const
850 return (parameters
->options().copyreloc()
851 && this->is_from_dynobj()
852 && !this->is_func());
855 // Return true if this symbol was predefined by the linker.
857 is_predefined() const
858 { return this->is_predefined_
; }
860 // Return true if this is a C++ vtable symbol.
862 is_cxx_vtable() const
863 { return is_prefix_of("_ZTV", this->name_
); }
866 // Instances of this class should always be created at a specific
869 { memset(this, 0, sizeof *this); }
871 // Initialize the general fields.
873 init_fields(const char* name
, const char* version
,
874 elfcpp::STT type
, elfcpp::STB binding
,
875 elfcpp::STV visibility
, unsigned char nonvis
);
877 // Initialize fields from an ELF symbol in OBJECT. ST_SHNDX is the
878 // section index, IS_ORDINARY is whether it is a normal section
879 // index rather than a special code.
880 template<int size
, bool big_endian
>
882 init_base_object(const char* name
, const char* version
, Object
* object
,
883 const elfcpp::Sym
<size
, big_endian
>&, unsigned int st_shndx
,
886 // Initialize fields for an Output_data.
888 init_base_output_data(const char* name
, const char* version
, Output_data
*,
889 elfcpp::STT
, elfcpp::STB
, elfcpp::STV
,
890 unsigned char nonvis
, bool offset_is_from_end
,
893 // Initialize fields for an Output_segment.
895 init_base_output_segment(const char* name
, const char* version
,
896 Output_segment
* os
, elfcpp::STT type
,
897 elfcpp::STB binding
, elfcpp::STV visibility
,
898 unsigned char nonvis
,
899 Segment_offset_base offset_base
,
902 // Initialize fields for a constant.
904 init_base_constant(const char* name
, const char* version
, elfcpp::STT type
,
905 elfcpp::STB binding
, elfcpp::STV visibility
,
906 unsigned char nonvis
, bool is_predefined
);
908 // Initialize fields for an undefined symbol.
910 init_base_undefined(const char* name
, const char* version
, elfcpp::STT type
,
911 elfcpp::STB binding
, elfcpp::STV visibility
,
912 unsigned char nonvis
);
914 // Override existing symbol.
915 template<int size
, bool big_endian
>
917 override_base(const elfcpp::Sym
<size
, big_endian
>&, unsigned int st_shndx
,
918 bool is_ordinary
, Object
* object
, const char* version
);
920 // Override existing symbol with a special symbol.
922 override_base_with_special(const Symbol
* from
);
924 // Override symbol version.
926 override_version(const char* version
);
928 // Allocate a common symbol by giving it a location in the output
931 allocate_base_common(Output_data
*);
934 Symbol(const Symbol
&);
935 Symbol
& operator=(const Symbol
&);
937 // Symbol name (expected to point into a Stringpool).
939 // Symbol version (expected to point into a Stringpool). This may
941 const char* version_
;
945 // This struct is used if SOURCE_ == FROM_OBJECT.
948 // Object in which symbol is defined, or in which it was first
951 // Section number in object_ in which symbol is defined.
955 // This struct is used if SOURCE_ == IN_OUTPUT_DATA.
958 // Output_data in which symbol is defined. Before
959 // Layout::finalize the symbol's value is an offset within the
961 Output_data
* output_data
;
962 // True if the offset is from the end, false if the offset is
963 // from the beginning.
964 bool offset_is_from_end
;
967 // This struct is used if SOURCE_ == IN_OUTPUT_SEGMENT.
970 // Output_segment in which the symbol is defined. Before
971 // Layout::finalize the symbol's value is an offset.
972 Output_segment
* output_segment
;
973 // The base to use for the offset before Layout::finalize.
974 Segment_offset_base offset_base
;
978 // The index of this symbol in the output file. If the symbol is
979 // not going into the output file, this value is -1U. This field
980 // starts as always holding zero. It is set to a non-zero value by
981 // Symbol_table::finalize.
982 unsigned int symtab_index_
;
984 // The index of this symbol in the dynamic symbol table. If the
985 // symbol is not going into the dynamic symbol table, this value is
986 // -1U. This field starts as always holding zero. It is set to a
987 // non-zero value during Layout::finalize.
988 unsigned int dynsym_index_
;
990 // The GOT section entries for this symbol. A symbol may have more
991 // than one GOT offset (e.g., when mixing modules compiled with two
992 // different TLS models), but will usually have at most one.
993 Got_offset_list got_offsets_
;
995 // If this symbol has an entry in the PLT section, then this is the
996 // offset from the start of the PLT section. This is -1U if there
998 unsigned int plt_offset_
;
1000 // Symbol type (bits 0 to 3).
1001 elfcpp::STT type_
: 4;
1002 // Symbol binding (bits 4 to 7).
1003 elfcpp::STB binding_
: 4;
1004 // Symbol visibility (bits 8 to 9).
1005 elfcpp::STV visibility_
: 2;
1006 // Rest of symbol st_other field (bits 10 to 15).
1007 unsigned int nonvis_
: 6;
1008 // The type of symbol (bits 16 to 18).
1010 // True if this is the default version of the symbol (bit 19).
1012 // True if this symbol really forwards to another symbol. This is
1013 // used when we discover after the fact that two different entries
1014 // in the hash table really refer to the same symbol. This will
1015 // never be set for a symbol found in the hash table, but may be set
1016 // for a symbol found in the list of symbols attached to an Object.
1017 // It forwards to the symbol found in the forwarders_ map of
1018 // Symbol_table (bit 20).
1019 bool is_forwarder_
: 1;
1020 // True if the symbol has an alias in the weak_aliases table in
1021 // Symbol_table (bit 21).
1022 bool has_alias_
: 1;
1023 // True if this symbol needs to be in the dynamic symbol table (bit
1025 bool needs_dynsym_entry_
: 1;
1026 // True if we've seen this symbol in a regular object (bit 23).
1028 // True if we've seen this symbol in a dynamic object (bit 24).
1030 // True if this is a dynamic symbol which needs a special value in
1031 // the dynamic symbol table (bit 25).
1032 bool needs_dynsym_value_
: 1;
1033 // True if there is a warning for this symbol (bit 26).
1034 bool has_warning_
: 1;
1035 // True if we are using a COPY reloc for this symbol, so that the
1036 // real definition lives in a dynamic object (bit 27).
1037 bool is_copied_from_dynobj_
: 1;
1038 // True if this symbol was forced to local visibility by a version
1040 bool is_forced_local_
: 1;
1041 // True if the field u_.from_object.shndx is an ordinary section
1042 // index, not one of the special codes from SHN_LORESERVE to
1043 // SHN_HIRESERVE (bit 29).
1044 bool is_ordinary_shndx_
: 1;
1045 // True if we've seen this symbol in a "real" ELF object (bit 30).
1046 // If the symbol has been seen in a relocatable, non-IR, object file,
1047 // it's known to be referenced from outside the IR. A reference from
1048 // a dynamic object doesn't count as a "real" ELF, and we'll simply
1049 // mark the symbol as "visible" from outside the IR. The compiler
1050 // can use this distinction to guide its handling of COMDAT symbols.
1051 bool in_real_elf_
: 1;
1052 // True if this symbol is defined in a section which was discarded
1054 bool is_defined_in_discarded_section_
: 1;
1055 // True if UNDEF_BINDING_WEAK_ has been set (bit 32).
1056 bool undef_binding_set_
: 1;
1057 // True if this symbol was a weak undef resolved by a dynamic def
1058 // or by a special symbol (bit 33).
1059 bool undef_binding_weak_
: 1;
1060 // True if this symbol is a predefined linker symbol (bit 34).
1061 bool is_predefined_
: 1;
1064 // The parts of a symbol which are size specific. Using a template
1065 // derived class like this helps us use less space on a 32-bit system.
1068 class Sized_symbol
: public Symbol
1071 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Value_type
;
1072 typedef typename
elfcpp::Elf_types
<size
>::Elf_WXword Size_type
;
1077 // Initialize fields from an ELF symbol in OBJECT. ST_SHNDX is the
1078 // section index, IS_ORDINARY is whether it is a normal section
1079 // index rather than a special code.
1080 template<bool big_endian
>
1082 init_object(const char* name
, const char* version
, Object
* object
,
1083 const elfcpp::Sym
<size
, big_endian
>&, unsigned int st_shndx
,
1086 // Initialize fields for an Output_data.
1088 init_output_data(const char* name
, const char* version
, Output_data
*,
1089 Value_type value
, Size_type symsize
, elfcpp::STT
,
1090 elfcpp::STB
, elfcpp::STV
, unsigned char nonvis
,
1091 bool offset_is_from_end
, bool is_predefined
);
1093 // Initialize fields for an Output_segment.
1095 init_output_segment(const char* name
, const char* version
, Output_segment
*,
1096 Value_type value
, Size_type symsize
, elfcpp::STT
,
1097 elfcpp::STB
, elfcpp::STV
, unsigned char nonvis
,
1098 Segment_offset_base offset_base
, bool is_predefined
);
1100 // Initialize fields for a constant.
1102 init_constant(const char* name
, const char* version
, Value_type value
,
1103 Size_type symsize
, elfcpp::STT
, elfcpp::STB
, elfcpp::STV
,
1104 unsigned char nonvis
, bool is_predefined
);
1106 // Initialize fields for an undefined symbol.
1108 init_undefined(const char* name
, const char* version
, elfcpp::STT
,
1109 elfcpp::STB
, elfcpp::STV
, unsigned char nonvis
);
1111 // Override existing symbol.
1112 template<bool big_endian
>
1114 override(const elfcpp::Sym
<size
, big_endian
>&, unsigned int st_shndx
,
1115 bool is_ordinary
, Object
* object
, const char* version
);
1117 // Override existing symbol with a special symbol.
1119 override_with_special(const Sized_symbol
<size
>*);
1121 // Return the symbol's value.
1124 { return this->value_
; }
1126 // Return the symbol's size (we can't call this 'size' because that
1127 // is a template parameter).
1130 { return this->symsize_
; }
1132 // Set the symbol size. This is used when resolving common symbols.
1134 set_symsize(Size_type symsize
)
1135 { this->symsize_
= symsize
; }
1137 // Set the symbol value. This is called when we store the final
1138 // values of the symbols into the symbol table.
1140 set_value(Value_type value
)
1141 { this->value_
= value
; }
1143 // Allocate a common symbol by giving it a location in the output
1146 allocate_common(Output_data
*, Value_type value
);
1149 Sized_symbol(const Sized_symbol
&);
1150 Sized_symbol
& operator=(const Sized_symbol
&);
1152 // Symbol value. Before Layout::finalize this is the offset in the
1153 // input section. This is set to the final value during
1154 // Layout::finalize.
1160 // A struct describing a symbol defined by the linker, where the value
1161 // of the symbol is defined based on an output section. This is used
1162 // for symbols defined by the linker, like "_init_array_start".
1164 struct Define_symbol_in_section
1168 // The name of the output section with which this symbol should be
1169 // associated. If there is no output section with that name, the
1170 // symbol will be defined as zero.
1171 const char* output_section
;
1172 // The offset of the symbol within the output section. This is an
1173 // offset from the start of the output section, unless start_at_end
1174 // is true, in which case this is an offset from the end of the
1177 // The size of the symbol.
1181 // The symbol binding.
1182 elfcpp::STB binding
;
1183 // The symbol visibility.
1184 elfcpp::STV visibility
;
1185 // The rest of the st_other field.
1186 unsigned char nonvis
;
1187 // If true, the value field is an offset from the end of the output
1189 bool offset_is_from_end
;
1190 // If true, this symbol is defined only if we see a reference to it.
1194 // A struct describing a symbol defined by the linker, where the value
1195 // of the symbol is defined based on a segment. This is used for
1196 // symbols defined by the linker, like "_end". We describe the
1197 // segment with which the symbol should be associated by its
1198 // characteristics. If no segment meets these characteristics, the
1199 // symbol will be defined as zero. If there is more than one segment
1200 // which meets these characteristics, we will use the first one.
1202 struct Define_symbol_in_segment
1206 // The segment type where the symbol should be defined, typically
1208 elfcpp::PT segment_type
;
1209 // Bitmask of segment flags which must be set.
1210 elfcpp::PF segment_flags_set
;
1211 // Bitmask of segment flags which must be clear.
1212 elfcpp::PF segment_flags_clear
;
1213 // The offset of the symbol within the segment. The offset is
1214 // calculated from the position set by offset_base.
1216 // The size of the symbol.
1220 // The symbol binding.
1221 elfcpp::STB binding
;
1222 // The symbol visibility.
1223 elfcpp::STV visibility
;
1224 // The rest of the st_other field.
1225 unsigned char nonvis
;
1226 // The base from which we compute the offset.
1227 Symbol::Segment_offset_base offset_base
;
1228 // If true, this symbol is defined only if we see a reference to it.
1232 // Specify an object/section/offset location. Used by ODR code.
1234 struct Symbol_location
1236 // Object where the symbol is defined.
1238 // Section-in-object where the symbol is defined.
1240 // For relocatable objects, offset-in-section where the symbol is defined.
1241 // For dynamic objects, address where the symbol is defined.
1243 bool operator==(const Symbol_location
& that
) const
1245 return (this->object
== that
.object
1246 && this->shndx
== that
.shndx
1247 && this->offset
== that
.offset
);
1251 // This class manages warnings. Warnings are a GNU extension. When
1252 // we see a section named .gnu.warning.SYM in an object file, and if
1253 // we wind using the definition of SYM from that object file, then we
1254 // will issue a warning for any relocation against SYM from a
1255 // different object file. The text of the warning is the contents of
1256 // the section. This is not precisely the definition used by the old
1257 // GNU linker; the old GNU linker treated an occurrence of
1258 // .gnu.warning.SYM as defining a warning symbol. A warning symbol
1259 // would trigger a warning on any reference. However, it was
1260 // inconsistent in that a warning in a dynamic object only triggered
1261 // if there was no definition in a regular object. This linker is
1262 // different in that we only issue a warning if we use the symbol
1263 // definition from the same object file as the warning section.
1272 // Add a warning for symbol NAME in object OBJ. WARNING is the text
1275 add_warning(Symbol_table
* symtab
, const char* name
, Object
* obj
,
1276 const std::string
& warning
);
1278 // For each symbol for which we should give a warning, make a note
1281 note_warnings(Symbol_table
* symtab
);
1283 // Issue a warning for a reference to SYM at RELINFO's location.
1284 template<int size
, bool big_endian
>
1286 issue_warning(const Symbol
* sym
, const Relocate_info
<size
, big_endian
>*,
1287 size_t relnum
, off_t reloffset
) const;
1290 Warnings(const Warnings
&);
1291 Warnings
& operator=(const Warnings
&);
1293 // What we need to know to get the warning text.
1294 struct Warning_location
1296 // The object the warning is in.
1298 // The warning text.
1302 : object(NULL
), text()
1306 set(Object
* o
, const std::string
& t
)
1313 // A mapping from warning symbol names (canonicalized in
1314 // Symbol_table's namepool_ field) to warning information.
1315 typedef Unordered_map
<const char*, Warning_location
> Warning_table
;
1317 Warning_table warnings_
;
1320 // The main linker symbol table.
1325 // The different places where a symbol definition can come from.
1328 // Defined in an object file--the normal case.
1330 // Defined for a COPY reloc.
1332 // Defined on the command line using --defsym.
1334 // Defined (so to speak) on the command line using -u.
1336 // Defined in a linker script.
1338 // Predefined by the linker.
1340 // Defined by the linker during an incremental base link, but not
1341 // a predefined symbol (e.g., common, defined in script).
1345 // The order in which we sort common symbols.
1346 enum Sort_commons_order
1348 SORT_COMMONS_BY_SIZE_DESCENDING
,
1349 SORT_COMMONS_BY_ALIGNMENT_DESCENDING
,
1350 SORT_COMMONS_BY_ALIGNMENT_ASCENDING
1353 // COUNT is an estimate of how many symbols will be inserted in the
1354 // symbol table. It's ok to put 0 if you don't know; a correct
1355 // guess will just save some CPU by reducing hashtable resizes.
1356 Symbol_table(unsigned int count
, const Version_script_info
& version_script
);
1362 { this->icf_
= icf
;}
1366 { return this->icf_
; }
1368 // Returns true if ICF determined that this is a duplicate section.
1370 is_section_folded(Object
* obj
, unsigned int shndx
) const;
1373 set_gc(Garbage_collection
* gc
)
1378 { return this->gc_
; }
1380 // During garbage collection, this keeps undefined symbols.
1382 gc_mark_undef_symbols(Layout
*);
1384 // This tells garbage collection that this symbol is referenced.
1386 gc_mark_symbol(Symbol
* sym
);
1388 // During garbage collection, this keeps sections that correspond to
1389 // symbols seen in dynamic objects.
1391 gc_mark_dyn_syms(Symbol
* sym
);
1393 // Add COUNT external symbols from the relocatable object RELOBJ to
1394 // the symbol table. SYMS is the symbols, SYMNDX_OFFSET is the
1395 // offset in the symbol table of the first symbol, SYM_NAMES is
1396 // their names, SYM_NAME_SIZE is the size of SYM_NAMES. This sets
1397 // SYMPOINTERS to point to the symbols in the symbol table. It sets
1398 // *DEFINED to the number of defined symbols.
1399 template<int size
, bool big_endian
>
1401 add_from_relobj(Sized_relobj_file
<size
, big_endian
>* relobj
,
1402 const unsigned char* syms
, size_t count
,
1403 size_t symndx_offset
, const char* sym_names
,
1404 size_t sym_name_size
,
1405 typename Sized_relobj_file
<size
, big_endian
>::Symbols
*,
1408 // Add one external symbol from the plugin object OBJ to the symbol table.
1409 // Returns a pointer to the resolved symbol in the symbol table.
1410 template<int size
, bool big_endian
>
1412 add_from_pluginobj(Sized_pluginobj
<size
, big_endian
>* obj
,
1413 const char* name
, const char* ver
,
1414 elfcpp::Sym
<size
, big_endian
>* sym
);
1416 // Add COUNT dynamic symbols from the dynamic object DYNOBJ to the
1417 // symbol table. SYMS is the symbols. SYM_NAMES is their names.
1418 // SYM_NAME_SIZE is the size of SYM_NAMES. The other parameters are
1419 // symbol version data.
1420 template<int size
, bool big_endian
>
1422 add_from_dynobj(Sized_dynobj
<size
, big_endian
>* dynobj
,
1423 const unsigned char* syms
, size_t count
,
1424 const char* sym_names
, size_t sym_name_size
,
1425 const unsigned char* versym
, size_t versym_size
,
1426 const std::vector
<const char*>*,
1427 typename Sized_relobj_file
<size
, big_endian
>::Symbols
*,
1430 // Add one external symbol from the incremental object OBJ to the symbol
1431 // table. Returns a pointer to the resolved symbol in the symbol table.
1432 template<int size
, bool big_endian
>
1434 add_from_incrobj(Object
* obj
, const char* name
,
1435 const char* ver
, elfcpp::Sym
<size
, big_endian
>* sym
);
1437 // Define a special symbol based on an Output_data. It is a
1438 // multiple definition error if this symbol is already defined.
1440 define_in_output_data(const char* name
, const char* version
, Defined
,
1441 Output_data
*, uint64_t value
, uint64_t symsize
,
1442 elfcpp::STT type
, elfcpp::STB binding
,
1443 elfcpp::STV visibility
, unsigned char nonvis
,
1444 bool offset_is_from_end
, bool only_if_ref
);
1446 // Define a special symbol based on an Output_segment. It is a
1447 // multiple definition error if this symbol is already defined.
1449 define_in_output_segment(const char* name
, const char* version
, Defined
,
1450 Output_segment
*, uint64_t value
, uint64_t symsize
,
1451 elfcpp::STT type
, elfcpp::STB binding
,
1452 elfcpp::STV visibility
, unsigned char nonvis
,
1453 Symbol::Segment_offset_base
, bool only_if_ref
);
1455 // Define a special symbol with a constant value. It is a multiple
1456 // definition error if this symbol is already defined.
1458 define_as_constant(const char* name
, const char* version
, Defined
,
1459 uint64_t value
, uint64_t symsize
, elfcpp::STT type
,
1460 elfcpp::STB binding
, elfcpp::STV visibility
,
1461 unsigned char nonvis
, bool only_if_ref
,
1462 bool force_override
);
1464 // Define a set of symbols in output sections. If ONLY_IF_REF is
1465 // true, only define them if they are referenced.
1467 define_symbols(const Layout
*, int count
, const Define_symbol_in_section
*,
1470 // Define a set of symbols in output segments. If ONLY_IF_REF is
1471 // true, only defined them if they are referenced.
1473 define_symbols(const Layout
*, int count
, const Define_symbol_in_segment
*,
1476 // Define SYM using a COPY reloc. POSD is the Output_data where the
1477 // symbol should be defined--typically a .dyn.bss section. VALUE is
1478 // the offset within POSD.
1481 define_with_copy_reloc(Sized_symbol
<size
>* sym
, Output_data
* posd
,
1482 typename
elfcpp::Elf_types
<size
>::Elf_Addr
);
1484 // Look up a symbol.
1486 lookup(const char*, const char* version
= NULL
) const;
1488 // Return the real symbol associated with the forwarder symbol FROM.
1490 resolve_forwards(const Symbol
* from
) const;
1492 // Return the sized version of a symbol in this table.
1495 get_sized_symbol(Symbol
*) const;
1498 const Sized_symbol
<size
>*
1499 get_sized_symbol(const Symbol
*) const;
1501 // Return the count of undefined symbols seen.
1503 saw_undefined() const
1504 { return this->saw_undefined_
; }
1506 // Allocate the common symbols
1508 allocate_commons(Layout
*, Mapfile
*);
1510 // Add a warning for symbol NAME in object OBJ. WARNING is the text
1513 add_warning(const char* name
, Object
* obj
, const std::string
& warning
)
1514 { this->warnings_
.add_warning(this, name
, obj
, warning
); }
1516 // Canonicalize a symbol name for use in the hash table.
1518 canonicalize_name(const char* name
)
1519 { return this->namepool_
.add(name
, true, NULL
); }
1521 // Possibly issue a warning for a reference to SYM at LOCATION which
1523 template<int size
, bool big_endian
>
1525 issue_warning(const Symbol
* sym
,
1526 const Relocate_info
<size
, big_endian
>* relinfo
,
1527 size_t relnum
, off_t reloffset
) const
1528 { this->warnings_
.issue_warning(sym
, relinfo
, relnum
, reloffset
); }
1530 // Check candidate_odr_violations_ to find symbols with the same name
1531 // but apparently different definitions (different source-file/line-no).
1533 detect_odr_violations(const Task
*, const char* output_file_name
) const;
1535 // Add any undefined symbols named on the command line to the symbol
1538 add_undefined_symbols_from_command_line(Layout
*);
1540 // SYM is defined using a COPY reloc. Return the dynamic object
1541 // where the original definition was found.
1543 get_copy_source(const Symbol
* sym
) const;
1545 // Set the dynamic symbol indexes. INDEX is the index of the first
1546 // global dynamic symbol. Pointers to the symbols are stored into
1547 // the vector. The names are stored into the Stringpool. This
1548 // returns an updated dynamic symbol index.
1550 set_dynsym_indexes(unsigned int index
, std::vector
<Symbol
*>*,
1551 Stringpool
*, Versions
*);
1553 // Finalize the symbol table after we have set the final addresses
1554 // of all the input sections. This sets the final symbol indexes,
1555 // values and adds the names to *POOL. *PLOCAL_SYMCOUNT is the
1556 // index of the first global symbol. OFF is the file offset of the
1557 // global symbol table, DYNOFF is the offset of the globals in the
1558 // dynamic symbol table, DYN_GLOBAL_INDEX is the index of the first
1559 // global dynamic symbol, and DYNCOUNT is the number of global
1560 // dynamic symbols. This records the parameters, and returns the
1561 // new file offset. It updates *PLOCAL_SYMCOUNT if it created any
1564 finalize(off_t off
, off_t dynoff
, size_t dyn_global_index
, size_t dyncount
,
1565 Stringpool
* pool
, unsigned int* plocal_symcount
);
1567 // Set the final file offset of the symbol table.
1569 set_file_offset(off_t off
)
1570 { this->offset_
= off
; }
1572 // Status code of Symbol_table::compute_final_value.
1573 enum Compute_final_value_status
1577 // Unsupported symbol section.
1578 CFVS_UNSUPPORTED_SYMBOL_SECTION
,
1579 // No output section.
1580 CFVS_NO_OUTPUT_SECTION
1583 // Compute the final value of SYM and store status in location PSTATUS.
1584 // During relaxation, this may be called multiple times for a symbol to
1585 // compute its would-be final value in each relaxation pass.
1588 typename Sized_symbol
<size
>::Value_type
1589 compute_final_value(const Sized_symbol
<size
>* sym
,
1590 Compute_final_value_status
* pstatus
) const;
1592 // Return the index of the first global symbol.
1594 first_global_index() const
1595 { return this->first_global_index_
; }
1597 // Return the total number of symbols in the symbol table.
1599 output_count() const
1600 { return this->output_count_
; }
1602 // Write out the global symbols.
1604 write_globals(const Stringpool
*, const Stringpool
*,
1605 Output_symtab_xindex
*, Output_symtab_xindex
*,
1606 Output_file
*) const;
1608 // Write out a section symbol. Return the updated offset.
1610 write_section_symbol(const Output_section
*, Output_symtab_xindex
*,
1611 Output_file
*, off_t
) const;
1613 // Loop over all symbols, applying the function F to each.
1614 template<int size
, typename F
>
1616 for_all_symbols(F f
) const
1618 for (Symbol_table_type::const_iterator p
= this->table_
.begin();
1619 p
!= this->table_
.end();
1622 Sized_symbol
<size
>* sym
= static_cast<Sized_symbol
<size
>*>(p
->second
);
1627 // Dump statistical information to stderr.
1629 print_stats() const;
1631 // Return the version script information.
1632 const Version_script_info
&
1633 version_script() const
1634 { return version_script_
; }
1637 Symbol_table(const Symbol_table
&);
1638 Symbol_table
& operator=(const Symbol_table
&);
1640 // The type of the list of common symbols.
1641 typedef std::vector
<Symbol
*> Commons_type
;
1643 // The type of the symbol hash table.
1645 typedef std::pair
<Stringpool::Key
, Stringpool::Key
> Symbol_table_key
;
1647 // The hash function. The key values are Stringpool keys.
1648 struct Symbol_table_hash
1651 operator()(const Symbol_table_key
& key
) const
1653 return key
.first
^ key
.second
;
1657 struct Symbol_table_eq
1660 operator()(const Symbol_table_key
&, const Symbol_table_key
&) const;
1663 typedef Unordered_map
<Symbol_table_key
, Symbol
*, Symbol_table_hash
,
1664 Symbol_table_eq
> Symbol_table_type
;
1666 // A map from symbol name (as a pointer into the namepool) to all
1667 // the locations the symbols is (weakly) defined (and certain other
1668 // conditions are met). This map will be used later to detect
1669 // possible One Definition Rule (ODR) violations.
1670 struct Symbol_location_hash
1672 size_t operator()(const Symbol_location
& loc
) const
1673 { return reinterpret_cast<uintptr_t>(loc
.object
) ^ loc
.offset
^ loc
.shndx
; }
1676 typedef Unordered_map
<const char*,
1677 Unordered_set
<Symbol_location
, Symbol_location_hash
> >
1680 // Make FROM a forwarder symbol to TO.
1682 make_forwarder(Symbol
* from
, Symbol
* to
);
1685 template<int size
, bool big_endian
>
1687 add_from_object(Object
*, const char* name
, Stringpool::Key name_key
,
1688 const char* version
, Stringpool::Key version_key
,
1689 bool def
, const elfcpp::Sym
<size
, big_endian
>& sym
,
1690 unsigned int st_shndx
, bool is_ordinary
,
1691 unsigned int orig_st_shndx
);
1693 // Define a default symbol.
1694 template<int size
, bool big_endian
>
1696 define_default_version(Sized_symbol
<size
>*, bool,
1697 Symbol_table_type::iterator
);
1700 template<int size
, bool big_endian
>
1702 resolve(Sized_symbol
<size
>* to
,
1703 const elfcpp::Sym
<size
, big_endian
>& sym
,
1704 unsigned int st_shndx
, bool is_ordinary
,
1705 unsigned int orig_st_shndx
,
1706 Object
*, const char* version
);
1708 template<int size
, bool big_endian
>
1710 resolve(Sized_symbol
<size
>* to
, const Sized_symbol
<size
>* from
);
1712 // Record that a symbol is forced to be local by a version script or
1715 force_local(Symbol
*);
1717 // Adjust NAME and *NAME_KEY for wrapping.
1719 wrap_symbol(const char* name
, Stringpool::Key
* name_key
);
1721 // Whether we should override a symbol, based on flags in
1724 should_override(const Symbol
*, unsigned int, elfcpp::STT
, Defined
,
1725 Object
*, bool*, bool*);
1727 // Report a problem in symbol resolution.
1729 report_resolve_problem(bool is_error
, const char* msg
, const Symbol
* to
,
1730 Defined
, Object
* object
);
1732 // Override a symbol.
1733 template<int size
, bool big_endian
>
1735 override(Sized_symbol
<size
>* tosym
,
1736 const elfcpp::Sym
<size
, big_endian
>& fromsym
,
1737 unsigned int st_shndx
, bool is_ordinary
,
1738 Object
* object
, const char* version
);
1740 // Whether we should override a symbol with a special symbol which
1741 // is automatically defined by the linker.
1743 should_override_with_special(const Symbol
*, elfcpp::STT
, Defined
);
1745 // Override a symbol with a special symbol.
1748 override_with_special(Sized_symbol
<size
>* tosym
,
1749 const Sized_symbol
<size
>* fromsym
);
1751 // Record all weak alias sets for a dynamic object.
1754 record_weak_aliases(std::vector
<Sized_symbol
<size
>*>*);
1756 // Define a special symbol.
1757 template<int size
, bool big_endian
>
1759 define_special_symbol(const char** pname
, const char** pversion
,
1760 bool only_if_ref
, Sized_symbol
<size
>** poldsym
,
1761 bool* resolve_oldsym
);
1763 // Define a symbol in an Output_data, sized version.
1766 do_define_in_output_data(const char* name
, const char* version
, Defined
,
1768 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1769 typename
elfcpp::Elf_types
<size
>::Elf_WXword ssize
,
1770 elfcpp::STT type
, elfcpp::STB binding
,
1771 elfcpp::STV visibility
, unsigned char nonvis
,
1772 bool offset_is_from_end
, bool only_if_ref
);
1774 // Define a symbol in an Output_segment, sized version.
1777 do_define_in_output_segment(
1778 const char* name
, const char* version
, Defined
, Output_segment
* os
,
1779 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1780 typename
elfcpp::Elf_types
<size
>::Elf_WXword ssize
,
1781 elfcpp::STT type
, elfcpp::STB binding
,
1782 elfcpp::STV visibility
, unsigned char nonvis
,
1783 Symbol::Segment_offset_base offset_base
, bool only_if_ref
);
1785 // Define a symbol as a constant, sized version.
1788 do_define_as_constant(
1789 const char* name
, const char* version
, Defined
,
1790 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1791 typename
elfcpp::Elf_types
<size
>::Elf_WXword ssize
,
1792 elfcpp::STT type
, elfcpp::STB binding
,
1793 elfcpp::STV visibility
, unsigned char nonvis
,
1794 bool only_if_ref
, bool force_override
);
1796 // Add any undefined symbols named on the command line to the symbol
1797 // table, sized version.
1800 do_add_undefined_symbols_from_command_line(Layout
*);
1802 // Add one undefined symbol.
1805 add_undefined_symbol_from_command_line(const char* name
);
1807 // Types of common symbols.
1809 enum Commons_section_type
1817 // Allocate the common symbols, sized version.
1820 do_allocate_commons(Layout
*, Mapfile
*, Sort_commons_order
);
1822 // Allocate the common symbols from one list.
1825 do_allocate_commons_list(Layout
*, Commons_section_type
, Commons_type
*,
1826 Mapfile
*, Sort_commons_order
);
1828 // Returns all of the lines attached to LOC, not just the one the
1829 // instruction actually came from. This helps the ODR checker avoid
1831 static std::vector
<std::string
>
1832 linenos_from_loc(const Task
* task
, const Symbol_location
& loc
);
1834 // Implement detect_odr_violations.
1835 template<int size
, bool big_endian
>
1837 sized_detect_odr_violations() const;
1839 // Finalize symbols specialized for size.
1842 sized_finalize(off_t
, Stringpool
*, unsigned int*);
1844 // Finalize a symbol. Return whether it should be added to the
1848 sized_finalize_symbol(Symbol
*);
1850 // Add a symbol the final symtab by setting its index.
1853 add_to_final_symtab(Symbol
*, Stringpool
*, unsigned int* pindex
, off_t
* poff
);
1855 // Write globals specialized for size and endianness.
1856 template<int size
, bool big_endian
>
1858 sized_write_globals(const Stringpool
*, const Stringpool
*,
1859 Output_symtab_xindex
*, Output_symtab_xindex
*,
1860 Output_file
*) const;
1862 // Write out a symbol to P.
1863 template<int size
, bool big_endian
>
1865 sized_write_symbol(Sized_symbol
<size
>*,
1866 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1867 unsigned int shndx
, elfcpp::STB
,
1868 const Stringpool
*, unsigned char* p
) const;
1870 // Possibly warn about an undefined symbol from a dynamic object.
1872 warn_about_undefined_dynobj_symbol(Symbol
*) const;
1874 // Write out a section symbol, specialized for size and endianness.
1875 template<int size
, bool big_endian
>
1877 sized_write_section_symbol(const Output_section
*, Output_symtab_xindex
*,
1878 Output_file
*, off_t
) const;
1880 // The type of the list of symbols which have been forced local.
1881 typedef std::vector
<Symbol
*> Forced_locals
;
1883 // A map from symbols with COPY relocs to the dynamic objects where
1884 // they are defined.
1885 typedef Unordered_map
<const Symbol
*, Dynobj
*> Copied_symbol_dynobjs
;
1887 // We increment this every time we see a new undefined symbol, for
1888 // use in archive groups.
1889 size_t saw_undefined_
;
1890 // The index of the first global symbol in the output file.
1891 unsigned int first_global_index_
;
1892 // The file offset within the output symtab section where we should
1895 // The number of global symbols we want to write out.
1896 unsigned int output_count_
;
1897 // The file offset of the global dynamic symbols, or 0 if none.
1898 off_t dynamic_offset_
;
1899 // The index of the first global dynamic symbol.
1900 unsigned int first_dynamic_global_index_
;
1901 // The number of global dynamic symbols, or 0 if none.
1902 unsigned int dynamic_count_
;
1903 // The symbol hash table.
1904 Symbol_table_type table_
;
1905 // A pool of symbol names. This is used for all global symbols.
1906 // Entries in the hash table point into this pool.
1907 Stringpool namepool_
;
1908 // Forwarding symbols.
1909 Unordered_map
<const Symbol
*, Symbol
*> forwarders_
;
1910 // Weak aliases. A symbol in this list points to the next alias.
1911 // The aliases point to each other in a circular list.
1912 Unordered_map
<Symbol
*, Symbol
*> weak_aliases_
;
1913 // We don't expect there to be very many common symbols, so we keep
1914 // a list of them. When we find a common symbol we add it to this
1915 // list. It is possible that by the time we process the list the
1916 // symbol is no longer a common symbol. It may also have become a
1918 Commons_type commons_
;
1919 // This is like the commons_ field, except that it holds TLS common
1921 Commons_type tls_commons_
;
1922 // This is for small common symbols.
1923 Commons_type small_commons_
;
1924 // This is for large common symbols.
1925 Commons_type large_commons_
;
1926 // A list of symbols which have been forced to be local. We don't
1927 // expect there to be very many of them, so we keep a list of them
1928 // rather than walking the whole table to find them.
1929 Forced_locals forced_locals_
;
1930 // Manage symbol warnings.
1932 // Manage potential One Definition Rule (ODR) violations.
1933 Odr_map candidate_odr_violations_
;
1935 // When we emit a COPY reloc for a symbol, we define it in an
1936 // Output_data. When it's time to emit version information for it,
1937 // we need to know the dynamic object in which we found the original
1938 // definition. This maps symbols with COPY relocs to the dynamic
1939 // object where they were defined.
1940 Copied_symbol_dynobjs copied_symbol_dynobjs_
;
1941 // Information parsed from the version script, if any.
1942 const Version_script_info
& version_script_
;
1943 Garbage_collection
* gc_
;
1947 // We inline get_sized_symbol for efficiency.
1951 Symbol_table::get_sized_symbol(Symbol
* sym
) const
1953 gold_assert(size
== parameters
->target().get_size());
1954 return static_cast<Sized_symbol
<size
>*>(sym
);
1958 const Sized_symbol
<size
>*
1959 Symbol_table::get_sized_symbol(const Symbol
* sym
) const
1961 gold_assert(size
== parameters
->target().get_size());
1962 return static_cast<const Sized_symbol
<size
>*>(sym
);
1965 } // End namespace gold.
1967 #endif // !defined(GOLD_SYMTAB_H)