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; }
886 // Return state of PowerPC64 ELFv2 specific flag.
888 non_zero_localentry() const
889 { return this->non_zero_localentry_
; }
891 // Set PowerPC64 ELFv2 specific flag.
893 set_non_zero_localentry()
894 { this->non_zero_localentry_
= true; }
897 // Instances of this class should always be created at a specific
900 { memset(this, 0, sizeof *this); }
902 // Initialize the general fields.
904 init_fields(const char* name
, const char* version
,
905 elfcpp::STT type
, elfcpp::STB binding
,
906 elfcpp::STV visibility
, unsigned char nonvis
);
908 // Initialize fields from an ELF symbol in OBJECT. ST_SHNDX is the
909 // section index, IS_ORDINARY is whether it is a normal section
910 // index rather than a special code.
911 template<int size
, bool big_endian
>
913 init_base_object(const char* name
, const char* version
, Object
* object
,
914 const elfcpp::Sym
<size
, big_endian
>&, unsigned int st_shndx
,
917 // Initialize fields for an Output_data.
919 init_base_output_data(const char* name
, const char* version
, Output_data
*,
920 elfcpp::STT
, elfcpp::STB
, elfcpp::STV
,
921 unsigned char nonvis
, bool offset_is_from_end
,
924 // Initialize fields for an Output_segment.
926 init_base_output_segment(const char* name
, const char* version
,
927 Output_segment
* os
, elfcpp::STT type
,
928 elfcpp::STB binding
, elfcpp::STV visibility
,
929 unsigned char nonvis
,
930 Segment_offset_base offset_base
,
933 // Initialize fields for a constant.
935 init_base_constant(const char* name
, const char* version
, elfcpp::STT type
,
936 elfcpp::STB binding
, elfcpp::STV visibility
,
937 unsigned char nonvis
, bool is_predefined
);
939 // Initialize fields for an undefined symbol.
941 init_base_undefined(const char* name
, const char* version
, elfcpp::STT type
,
942 elfcpp::STB binding
, elfcpp::STV visibility
,
943 unsigned char nonvis
);
945 // Override existing symbol.
946 template<int size
, bool big_endian
>
948 override_base(const elfcpp::Sym
<size
, big_endian
>&, unsigned int st_shndx
,
949 bool is_ordinary
, Object
* object
, const char* version
);
951 // Override existing symbol with a special symbol.
953 override_base_with_special(const Symbol
* from
);
955 // Override symbol version.
957 override_version(const char* version
);
959 // Allocate a common symbol by giving it a location in the output
962 allocate_base_common(Output_data
*);
965 Symbol(const Symbol
&);
966 Symbol
& operator=(const Symbol
&);
968 // Symbol name (expected to point into a Stringpool).
970 // Symbol version (expected to point into a Stringpool). This may
972 const char* version_
;
976 // This struct is used if SOURCE_ == FROM_OBJECT.
979 // Object in which symbol is defined, or in which it was first
982 // Section number in object_ in which symbol is defined.
986 // This struct is used if SOURCE_ == IN_OUTPUT_DATA.
989 // Output_data in which symbol is defined. Before
990 // Layout::finalize the symbol's value is an offset within the
992 Output_data
* output_data
;
993 // True if the offset is from the end, false if the offset is
994 // from the beginning.
995 bool offset_is_from_end
;
998 // This struct is used if SOURCE_ == IN_OUTPUT_SEGMENT.
1001 // Output_segment in which the symbol is defined. Before
1002 // Layout::finalize the symbol's value is an offset.
1003 Output_segment
* output_segment
;
1004 // The base to use for the offset before Layout::finalize.
1005 Segment_offset_base offset_base
;
1006 } in_output_segment
;
1009 // The index of this symbol in the output file. If the symbol is
1010 // not going into the output file, this value is -1U. This field
1011 // starts as always holding zero. It is set to a non-zero value by
1012 // Symbol_table::finalize.
1013 unsigned int symtab_index_
;
1015 // The index of this symbol in the dynamic symbol table. If the
1016 // symbol is not going into the dynamic symbol table, this value is
1017 // -1U. This field starts as always holding zero. It is set to a
1018 // non-zero value during Layout::finalize.
1019 unsigned int dynsym_index_
;
1021 // The GOT section entries for this symbol. A symbol may have more
1022 // than one GOT offset (e.g., when mixing modules compiled with two
1023 // different TLS models), but will usually have at most one.
1024 Got_offset_list got_offsets_
;
1026 // If this symbol has an entry in the PLT section, then this is the
1027 // offset from the start of the PLT section. This is -1U if there
1029 unsigned int plt_offset_
;
1031 // Symbol type (bits 0 to 3).
1032 elfcpp::STT type_
: 4;
1033 // Symbol binding (bits 4 to 7).
1034 elfcpp::STB binding_
: 4;
1035 // Symbol visibility (bits 8 to 9).
1036 elfcpp::STV visibility_
: 2;
1037 // Rest of symbol st_other field (bits 10 to 15).
1038 unsigned int nonvis_
: 6;
1039 // The type of symbol (bits 16 to 18).
1041 // True if this is the default version of the symbol (bit 19).
1043 // True if this symbol really forwards to another symbol. This is
1044 // used when we discover after the fact that two different entries
1045 // in the hash table really refer to the same symbol. This will
1046 // never be set for a symbol found in the hash table, but may be set
1047 // for a symbol found in the list of symbols attached to an Object.
1048 // It forwards to the symbol found in the forwarders_ map of
1049 // Symbol_table (bit 20).
1050 bool is_forwarder_
: 1;
1051 // True if the symbol has an alias in the weak_aliases table in
1052 // Symbol_table (bit 21).
1053 bool has_alias_
: 1;
1054 // True if this symbol needs to be in the dynamic symbol table (bit
1056 bool needs_dynsym_entry_
: 1;
1057 // True if we've seen this symbol in a regular object (bit 23).
1059 // True if we've seen this symbol in a dynamic object (bit 24).
1061 // True if this is a dynamic symbol which needs a special value in
1062 // the dynamic symbol table (bit 25).
1063 bool needs_dynsym_value_
: 1;
1064 // True if there is a warning for this symbol (bit 26).
1065 bool has_warning_
: 1;
1066 // True if we are using a COPY reloc for this symbol, so that the
1067 // real definition lives in a dynamic object (bit 27).
1068 bool is_copied_from_dynobj_
: 1;
1069 // True if this symbol was forced to local visibility by a version
1071 bool is_forced_local_
: 1;
1072 // True if the field u_.from_object.shndx is an ordinary section
1073 // index, not one of the special codes from SHN_LORESERVE to
1074 // SHN_HIRESERVE (bit 29).
1075 bool is_ordinary_shndx_
: 1;
1076 // True if we've seen this symbol in a "real" ELF object (bit 30).
1077 // If the symbol has been seen in a relocatable, non-IR, object file,
1078 // it's known to be referenced from outside the IR. A reference from
1079 // a dynamic object doesn't count as a "real" ELF, and we'll simply
1080 // mark the symbol as "visible" from outside the IR. The compiler
1081 // can use this distinction to guide its handling of COMDAT symbols.
1082 bool in_real_elf_
: 1;
1083 // True if this symbol is defined in a section which was discarded
1085 bool is_defined_in_discarded_section_
: 1;
1086 // True if UNDEF_BINDING_WEAK_ has been set (bit 32).
1087 bool undef_binding_set_
: 1;
1088 // True if this symbol was a weak undef resolved by a dynamic def
1089 // or by a special symbol (bit 33).
1090 bool undef_binding_weak_
: 1;
1091 // True if this symbol is a predefined linker symbol (bit 34).
1092 bool is_predefined_
: 1;
1093 // True if this symbol has protected visibility in a shared object (bit 35).
1094 // The visibility_ field will be STV_DEFAULT in this case because we
1095 // must treat it as such from outside the shared object.
1096 bool is_protected_
: 1;
1097 // Used by PowerPC64 ELFv2 to track st_other localentry (bit 36).
1098 bool non_zero_localentry_
: 1;
1101 // The parts of a symbol which are size specific. Using a template
1102 // derived class like this helps us use less space on a 32-bit system.
1105 class Sized_symbol
: public Symbol
1108 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Value_type
;
1109 typedef typename
elfcpp::Elf_types
<size
>::Elf_WXword Size_type
;
1114 // Initialize fields from an ELF symbol in OBJECT. ST_SHNDX is the
1115 // section index, IS_ORDINARY is whether it is a normal section
1116 // index rather than a special code.
1117 template<bool big_endian
>
1119 init_object(const char* name
, const char* version
, Object
* object
,
1120 const elfcpp::Sym
<size
, big_endian
>&, unsigned int st_shndx
,
1123 // Initialize fields for an Output_data.
1125 init_output_data(const char* name
, const char* version
, Output_data
*,
1126 Value_type value
, Size_type symsize
, elfcpp::STT
,
1127 elfcpp::STB
, elfcpp::STV
, unsigned char nonvis
,
1128 bool offset_is_from_end
, bool is_predefined
);
1130 // Initialize fields for an Output_segment.
1132 init_output_segment(const char* name
, const char* version
, Output_segment
*,
1133 Value_type value
, Size_type symsize
, elfcpp::STT
,
1134 elfcpp::STB
, elfcpp::STV
, unsigned char nonvis
,
1135 Segment_offset_base offset_base
, bool is_predefined
);
1137 // Initialize fields for a constant.
1139 init_constant(const char* name
, const char* version
, Value_type value
,
1140 Size_type symsize
, elfcpp::STT
, elfcpp::STB
, elfcpp::STV
,
1141 unsigned char nonvis
, bool is_predefined
);
1143 // Initialize fields for an undefined symbol.
1145 init_undefined(const char* name
, const char* version
, Value_type value
,
1146 elfcpp::STT
, elfcpp::STB
, elfcpp::STV
, unsigned char nonvis
);
1148 // Override existing symbol.
1149 template<bool big_endian
>
1151 override(const elfcpp::Sym
<size
, big_endian
>&, unsigned int st_shndx
,
1152 bool is_ordinary
, Object
* object
, const char* version
);
1154 // Override existing symbol with a special symbol.
1156 override_with_special(const Sized_symbol
<size
>*);
1158 // Return the symbol's value.
1161 { return this->value_
; }
1163 // Return the symbol's size (we can't call this 'size' because that
1164 // is a template parameter).
1167 { return this->symsize_
; }
1169 // Set the symbol size. This is used when resolving common symbols.
1171 set_symsize(Size_type symsize
)
1172 { this->symsize_
= symsize
; }
1174 // Set the symbol value. This is called when we store the final
1175 // values of the symbols into the symbol table.
1177 set_value(Value_type value
)
1178 { this->value_
= value
; }
1180 // Allocate a common symbol by giving it a location in the output
1183 allocate_common(Output_data
*, Value_type value
);
1186 Sized_symbol(const Sized_symbol
&);
1187 Sized_symbol
& operator=(const Sized_symbol
&);
1189 // Symbol value. Before Layout::finalize this is the offset in the
1190 // input section. This is set to the final value during
1191 // Layout::finalize.
1197 // A struct describing a symbol defined by the linker, where the value
1198 // of the symbol is defined based on an output section. This is used
1199 // for symbols defined by the linker, like "_init_array_start".
1201 struct Define_symbol_in_section
1205 // The name of the output section with which this symbol should be
1206 // associated. If there is no output section with that name, the
1207 // symbol will be defined as zero.
1208 const char* output_section
;
1209 // The offset of the symbol within the output section. This is an
1210 // offset from the start of the output section, unless start_at_end
1211 // is true, in which case this is an offset from the end of the
1214 // The size of the symbol.
1218 // The symbol binding.
1219 elfcpp::STB binding
;
1220 // The symbol visibility.
1221 elfcpp::STV visibility
;
1222 // The rest of the st_other field.
1223 unsigned char nonvis
;
1224 // If true, the value field is an offset from the end of the output
1226 bool offset_is_from_end
;
1227 // If true, this symbol is defined only if we see a reference to it.
1231 // A struct describing a symbol defined by the linker, where the value
1232 // of the symbol is defined based on a segment. This is used for
1233 // symbols defined by the linker, like "_end". We describe the
1234 // segment with which the symbol should be associated by its
1235 // characteristics. If no segment meets these characteristics, the
1236 // symbol will be defined as zero. If there is more than one segment
1237 // which meets these characteristics, we will use the first one.
1239 struct Define_symbol_in_segment
1243 // The segment type where the symbol should be defined, typically
1245 elfcpp::PT segment_type
;
1246 // Bitmask of segment flags which must be set.
1247 elfcpp::PF segment_flags_set
;
1248 // Bitmask of segment flags which must be clear.
1249 elfcpp::PF segment_flags_clear
;
1250 // The offset of the symbol within the segment. The offset is
1251 // calculated from the position set by offset_base.
1253 // The size of the symbol.
1257 // The symbol binding.
1258 elfcpp::STB binding
;
1259 // The symbol visibility.
1260 elfcpp::STV visibility
;
1261 // The rest of the st_other field.
1262 unsigned char nonvis
;
1263 // The base from which we compute the offset.
1264 Symbol::Segment_offset_base offset_base
;
1265 // If true, this symbol is defined only if we see a reference to it.
1269 // Specify an object/section/offset location. Used by ODR code.
1271 struct Symbol_location
1273 // Object where the symbol is defined.
1275 // Section-in-object where the symbol is defined.
1277 // For relocatable objects, offset-in-section where the symbol is defined.
1278 // For dynamic objects, address where the symbol is defined.
1280 bool operator==(const Symbol_location
& that
) const
1282 return (this->object
== that
.object
1283 && this->shndx
== that
.shndx
1284 && this->offset
== that
.offset
);
1288 // A map from symbol name (as a pointer into the namepool) to all
1289 // the locations the symbols is (weakly) defined (and certain other
1290 // conditions are met). This map will be used later to detect
1291 // possible One Definition Rule (ODR) violations.
1292 struct Symbol_location_hash
1294 size_t operator()(const Symbol_location
& loc
) const
1295 { return reinterpret_cast<uintptr_t>(loc
.object
) ^ loc
.offset
^ loc
.shndx
; }
1298 // This class manages warnings. Warnings are a GNU extension. When
1299 // we see a section named .gnu.warning.SYM in an object file, and if
1300 // we wind using the definition of SYM from that object file, then we
1301 // will issue a warning for any relocation against SYM from a
1302 // different object file. The text of the warning is the contents of
1303 // the section. This is not precisely the definition used by the old
1304 // GNU linker; the old GNU linker treated an occurrence of
1305 // .gnu.warning.SYM as defining a warning symbol. A warning symbol
1306 // would trigger a warning on any reference. However, it was
1307 // inconsistent in that a warning in a dynamic object only triggered
1308 // if there was no definition in a regular object. This linker is
1309 // different in that we only issue a warning if we use the symbol
1310 // definition from the same object file as the warning section.
1319 // Add a warning for symbol NAME in object OBJ. WARNING is the text
1322 add_warning(Symbol_table
* symtab
, const char* name
, Object
* obj
,
1323 const std::string
& warning
);
1325 // For each symbol for which we should give a warning, make a note
1328 note_warnings(Symbol_table
* symtab
);
1330 // Issue a warning for a reference to SYM at RELINFO's location.
1331 template<int size
, bool big_endian
>
1333 issue_warning(const Symbol
* sym
, const Relocate_info
<size
, big_endian
>*,
1334 size_t relnum
, off_t reloffset
) const;
1337 Warnings(const Warnings
&);
1338 Warnings
& operator=(const Warnings
&);
1340 // What we need to know to get the warning text.
1341 struct Warning_location
1343 // The object the warning is in.
1345 // The warning text.
1349 : object(NULL
), text()
1353 set(Object
* o
, const std::string
& t
)
1360 // A mapping from warning symbol names (canonicalized in
1361 // Symbol_table's namepool_ field) to warning information.
1362 typedef Unordered_map
<const char*, Warning_location
> Warning_table
;
1364 Warning_table warnings_
;
1367 // The main linker symbol table.
1372 // The different places where a symbol definition can come from.
1375 // Defined in an object file--the normal case.
1377 // Defined for a COPY reloc.
1379 // Defined on the command line using --defsym.
1381 // Defined (so to speak) on the command line using -u.
1383 // Defined in a linker script.
1385 // Predefined by the linker.
1387 // Defined by the linker during an incremental base link, but not
1388 // a predefined symbol (e.g., common, defined in script).
1392 // The order in which we sort common symbols.
1393 enum Sort_commons_order
1395 SORT_COMMONS_BY_SIZE_DESCENDING
,
1396 SORT_COMMONS_BY_ALIGNMENT_DESCENDING
,
1397 SORT_COMMONS_BY_ALIGNMENT_ASCENDING
1400 // COUNT is an estimate of how many symbols will be inserted in the
1401 // symbol table. It's ok to put 0 if you don't know; a correct
1402 // guess will just save some CPU by reducing hashtable resizes.
1403 Symbol_table(unsigned int count
, const Version_script_info
& version_script
);
1409 { this->icf_
= icf
;}
1413 { return this->icf_
; }
1415 // Returns true if ICF determined that this is a duplicate section.
1417 is_section_folded(Relobj
* obj
, unsigned int shndx
) const;
1420 set_gc(Garbage_collection
* gc
)
1425 { return this->gc_
; }
1427 // During garbage collection, this keeps undefined symbols.
1429 gc_mark_undef_symbols(Layout
*);
1431 // This tells garbage collection that this symbol is referenced.
1433 gc_mark_symbol(Symbol
* sym
);
1435 // During garbage collection, this keeps sections that correspond to
1436 // symbols seen in dynamic objects.
1438 gc_mark_dyn_syms(Symbol
* sym
);
1440 // Add COUNT external symbols from the relocatable object RELOBJ to
1441 // the symbol table. SYMS is the symbols, SYMNDX_OFFSET is the
1442 // offset in the symbol table of the first symbol, SYM_NAMES is
1443 // their names, SYM_NAME_SIZE is the size of SYM_NAMES. This sets
1444 // SYMPOINTERS to point to the symbols in the symbol table. It sets
1445 // *DEFINED to the number of defined symbols.
1446 template<int size
, bool big_endian
>
1448 add_from_relobj(Sized_relobj_file
<size
, big_endian
>* relobj
,
1449 const unsigned char* syms
, size_t count
,
1450 size_t symndx_offset
, const char* sym_names
,
1451 size_t sym_name_size
,
1452 typename Sized_relobj_file
<size
, big_endian
>::Symbols
*,
1455 // Add one external symbol from the plugin object OBJ to the symbol table.
1456 // Returns a pointer to the resolved symbol in the symbol table.
1457 template<int size
, bool big_endian
>
1459 add_from_pluginobj(Sized_pluginobj
<size
, big_endian
>* obj
,
1460 const char* name
, const char* ver
,
1461 elfcpp::Sym
<size
, big_endian
>* sym
);
1463 // Add COUNT dynamic symbols from the dynamic object DYNOBJ to the
1464 // symbol table. SYMS is the symbols. SYM_NAMES is their names.
1465 // SYM_NAME_SIZE is the size of SYM_NAMES. The other parameters are
1466 // symbol version data.
1467 template<int size
, bool big_endian
>
1469 add_from_dynobj(Sized_dynobj
<size
, big_endian
>* dynobj
,
1470 const unsigned char* syms
, size_t count
,
1471 const char* sym_names
, size_t sym_name_size
,
1472 const unsigned char* versym
, size_t versym_size
,
1473 const std::vector
<const char*>*,
1474 typename Sized_relobj_file
<size
, big_endian
>::Symbols
*,
1477 // Add one external symbol from the incremental object OBJ to the symbol
1478 // table. Returns a pointer to the resolved symbol in the symbol table.
1479 template<int size
, bool big_endian
>
1481 add_from_incrobj(Object
* obj
, const char* name
,
1482 const char* ver
, elfcpp::Sym
<size
, big_endian
>* sym
);
1484 // Define a special symbol based on an Output_data. It is a
1485 // multiple definition error if this symbol is already defined.
1487 define_in_output_data(const char* name
, const char* version
, Defined
,
1488 Output_data
*, uint64_t value
, uint64_t symsize
,
1489 elfcpp::STT type
, elfcpp::STB binding
,
1490 elfcpp::STV visibility
, unsigned char nonvis
,
1491 bool offset_is_from_end
, bool only_if_ref
);
1493 // Define a special symbol based on an Output_segment. It is a
1494 // multiple definition error if this symbol is already defined.
1496 define_in_output_segment(const char* name
, const char* version
, Defined
,
1497 Output_segment
*, uint64_t value
, uint64_t symsize
,
1498 elfcpp::STT type
, elfcpp::STB binding
,
1499 elfcpp::STV visibility
, unsigned char nonvis
,
1500 Symbol::Segment_offset_base
, bool only_if_ref
);
1502 // Define a special symbol with a constant value. It is a multiple
1503 // definition error if this symbol is already defined.
1505 define_as_constant(const char* name
, const char* version
, Defined
,
1506 uint64_t value
, uint64_t symsize
, elfcpp::STT type
,
1507 elfcpp::STB binding
, elfcpp::STV visibility
,
1508 unsigned char nonvis
, bool only_if_ref
,
1509 bool force_override
);
1511 // Define a set of symbols in output sections. If ONLY_IF_REF is
1512 // true, only define them if they are referenced.
1514 define_symbols(const Layout
*, int count
, const Define_symbol_in_section
*,
1517 // Define a set of symbols in output segments. If ONLY_IF_REF is
1518 // true, only defined them if they are referenced.
1520 define_symbols(const Layout
*, int count
, const Define_symbol_in_segment
*,
1523 // Add a target-specific global symbol.
1524 // (Used by SPARC backend to add STT_SPARC_REGISTER symbols.)
1526 add_target_global_symbol(Symbol
* sym
)
1527 { this->target_symbols_
.push_back(sym
); }
1529 // Define SYM using a COPY reloc. POSD is the Output_data where the
1530 // symbol should be defined--typically a .dyn.bss section. VALUE is
1531 // the offset within POSD.
1534 define_with_copy_reloc(Sized_symbol
<size
>* sym
, Output_data
* posd
,
1535 typename
elfcpp::Elf_types
<size
>::Elf_Addr
);
1537 // Look up a symbol.
1539 lookup(const char*, const char* version
= NULL
) const;
1541 // Return the real symbol associated with the forwarder symbol FROM.
1543 resolve_forwards(const Symbol
* from
) const;
1545 // Return the sized version of a symbol in this table.
1548 get_sized_symbol(Symbol
*) const;
1551 const Sized_symbol
<size
>*
1552 get_sized_symbol(const Symbol
*) const;
1554 // Return the count of undefined symbols seen.
1556 saw_undefined() const
1557 { return this->saw_undefined_
; }
1559 // Allocate the common symbols
1561 allocate_commons(Layout
*, Mapfile
*);
1563 // Add a warning for symbol NAME in object OBJ. WARNING is the text
1566 add_warning(const char* name
, Object
* obj
, const std::string
& warning
)
1567 { this->warnings_
.add_warning(this, name
, obj
, warning
); }
1569 // Canonicalize a symbol name for use in the hash table.
1571 canonicalize_name(const char* name
)
1572 { return this->namepool_
.add(name
, true, NULL
); }
1574 // Possibly issue a warning for a reference to SYM at LOCATION which
1576 template<int size
, bool big_endian
>
1578 issue_warning(const Symbol
* sym
,
1579 const Relocate_info
<size
, big_endian
>* relinfo
,
1580 size_t relnum
, off_t reloffset
) const
1581 { this->warnings_
.issue_warning(sym
, relinfo
, relnum
, reloffset
); }
1583 // Check candidate_odr_violations_ to find symbols with the same name
1584 // but apparently different definitions (different source-file/line-no).
1586 detect_odr_violations(const Task
*, const char* output_file_name
) const;
1588 // Add any undefined symbols named on the command line to the symbol
1591 add_undefined_symbols_from_command_line(Layout
*);
1593 // SYM is defined using a COPY reloc. Return the dynamic object
1594 // where the original definition was found.
1596 get_copy_source(const Symbol
* sym
) const;
1598 // Set the dynamic symbol indexes. INDEX is the index of the first
1599 // global dynamic symbol. Return the count of forced-local symbols in
1600 // *PFORCED_LOCAL_COUNT. Pointers to the symbols are stored into
1601 // the vector. The names are stored into the Stringpool. This
1602 // returns an updated dynamic symbol index.
1604 set_dynsym_indexes(unsigned int index
, unsigned int* pforced_local_count
,
1605 std::vector
<Symbol
*>*, Stringpool
*, Versions
*);
1607 // Finalize the symbol table after we have set the final addresses
1608 // of all the input sections. This sets the final symbol indexes,
1609 // values and adds the names to *POOL. *PLOCAL_SYMCOUNT is the
1610 // index of the first global symbol. OFF is the file offset of the
1611 // global symbol table, DYNOFF is the offset of the globals in the
1612 // dynamic symbol table, DYN_GLOBAL_INDEX is the index of the first
1613 // global dynamic symbol, and DYNCOUNT is the number of global
1614 // dynamic symbols. This records the parameters, and returns the
1615 // new file offset. It updates *PLOCAL_SYMCOUNT if it created any
1618 finalize(off_t off
, off_t dynoff
, size_t dyn_global_index
, size_t dyncount
,
1619 Stringpool
* pool
, unsigned int* plocal_symcount
);
1621 // Set the final file offset of the symbol table.
1623 set_file_offset(off_t off
)
1624 { this->offset_
= off
; }
1626 // Status code of Symbol_table::compute_final_value.
1627 enum Compute_final_value_status
1631 // Unsupported symbol section.
1632 CFVS_UNSUPPORTED_SYMBOL_SECTION
,
1633 // No output section.
1634 CFVS_NO_OUTPUT_SECTION
1637 // Compute the final value of SYM and store status in location PSTATUS.
1638 // During relaxation, this may be called multiple times for a symbol to
1639 // compute its would-be final value in each relaxation pass.
1642 typename Sized_symbol
<size
>::Value_type
1643 compute_final_value(const Sized_symbol
<size
>* sym
,
1644 Compute_final_value_status
* pstatus
) const;
1646 // Return the index of the first global symbol.
1648 first_global_index() const
1649 { return this->first_global_index_
; }
1651 // Return the total number of symbols in the symbol table.
1653 output_count() const
1654 { return this->output_count_
; }
1656 // Write out the global symbols.
1658 write_globals(const Stringpool
*, const Stringpool
*,
1659 Output_symtab_xindex
*, Output_symtab_xindex
*,
1660 Output_file
*) const;
1662 // Write out a section symbol. Return the updated offset.
1664 write_section_symbol(const Output_section
*, Output_symtab_xindex
*,
1665 Output_file
*, off_t
) const;
1667 // Loop over all symbols, applying the function F to each.
1668 template<int size
, typename F
>
1670 for_all_symbols(F f
) const
1672 for (Symbol_table_type::const_iterator p
= this->table_
.begin();
1673 p
!= this->table_
.end();
1676 Sized_symbol
<size
>* sym
= static_cast<Sized_symbol
<size
>*>(p
->second
);
1681 // Dump statistical information to stderr.
1683 print_stats() const;
1685 // Return the version script information.
1686 const Version_script_info
&
1687 version_script() const
1688 { return version_script_
; }
1691 Symbol_table(const Symbol_table
&);
1692 Symbol_table
& operator=(const Symbol_table
&);
1694 // The type of the list of common symbols.
1695 typedef std::vector
<Symbol
*> Commons_type
;
1697 // The type of the symbol hash table.
1699 typedef std::pair
<Stringpool::Key
, Stringpool::Key
> Symbol_table_key
;
1701 // The hash function. The key values are Stringpool keys.
1702 struct Symbol_table_hash
1705 operator()(const Symbol_table_key
& key
) const
1707 return key
.first
^ key
.second
;
1711 struct Symbol_table_eq
1714 operator()(const Symbol_table_key
&, const Symbol_table_key
&) const;
1717 typedef Unordered_map
<Symbol_table_key
, Symbol
*, Symbol_table_hash
,
1718 Symbol_table_eq
> Symbol_table_type
;
1720 typedef Unordered_map
<const char*,
1721 Unordered_set
<Symbol_location
, Symbol_location_hash
> >
1724 // Make FROM a forwarder symbol to TO.
1726 make_forwarder(Symbol
* from
, Symbol
* to
);
1729 template<int size
, bool big_endian
>
1731 add_from_object(Object
*, const char* name
, Stringpool::Key name_key
,
1732 const char* version
, Stringpool::Key version_key
,
1733 bool def
, const elfcpp::Sym
<size
, big_endian
>& sym
,
1734 unsigned int st_shndx
, bool is_ordinary
,
1735 unsigned int orig_st_shndx
);
1737 // Define a default symbol.
1738 template<int size
, bool big_endian
>
1740 define_default_version(Sized_symbol
<size
>*, bool,
1741 Symbol_table_type::iterator
);
1744 template<int size
, bool big_endian
>
1746 resolve(Sized_symbol
<size
>* to
,
1747 const elfcpp::Sym
<size
, big_endian
>& sym
,
1748 unsigned int st_shndx
, bool is_ordinary
,
1749 unsigned int orig_st_shndx
,
1750 Object
*, const char* version
,
1751 bool is_default_version
);
1753 template<int size
, bool big_endian
>
1755 resolve(Sized_symbol
<size
>* to
, const Sized_symbol
<size
>* from
);
1757 // Record that a symbol is forced to be local by a version script or
1760 force_local(Symbol
*);
1762 // Adjust NAME and *NAME_KEY for wrapping.
1764 wrap_symbol(const char* name
, Stringpool::Key
* name_key
);
1766 // Whether we should override a symbol, based on flags in
1769 should_override(const Symbol
*, unsigned int, elfcpp::STT
, Defined
,
1770 Object
*, bool*, bool*, bool);
1772 // Report a problem in symbol resolution.
1774 report_resolve_problem(bool is_error
, const char* msg
, const Symbol
* to
,
1775 Defined
, Object
* object
);
1777 // Override a symbol.
1778 template<int size
, bool big_endian
>
1780 override(Sized_symbol
<size
>* tosym
,
1781 const elfcpp::Sym
<size
, big_endian
>& fromsym
,
1782 unsigned int st_shndx
, bool is_ordinary
,
1783 Object
* object
, const char* version
);
1785 // Whether we should override a symbol with a special symbol which
1786 // is automatically defined by the linker.
1788 should_override_with_special(const Symbol
*, elfcpp::STT
, Defined
);
1790 // Override a symbol with a special symbol.
1793 override_with_special(Sized_symbol
<size
>* tosym
,
1794 const Sized_symbol
<size
>* fromsym
);
1796 // Record all weak alias sets for a dynamic object.
1799 record_weak_aliases(std::vector
<Sized_symbol
<size
>*>*);
1801 // Define a special symbol.
1802 template<int size
, bool big_endian
>
1804 define_special_symbol(const char** pname
, const char** pversion
,
1805 bool only_if_ref
, Sized_symbol
<size
>** poldsym
,
1806 bool* resolve_oldsym
, bool is_forced_local
);
1808 // Define a symbol in an Output_data, sized version.
1811 do_define_in_output_data(const char* name
, const char* version
, Defined
,
1813 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1814 typename
elfcpp::Elf_types
<size
>::Elf_WXword ssize
,
1815 elfcpp::STT type
, elfcpp::STB binding
,
1816 elfcpp::STV visibility
, unsigned char nonvis
,
1817 bool offset_is_from_end
, bool only_if_ref
);
1819 // Define a symbol in an Output_segment, sized version.
1822 do_define_in_output_segment(
1823 const char* name
, const char* version
, Defined
, Output_segment
* os
,
1824 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1825 typename
elfcpp::Elf_types
<size
>::Elf_WXword ssize
,
1826 elfcpp::STT type
, elfcpp::STB binding
,
1827 elfcpp::STV visibility
, unsigned char nonvis
,
1828 Symbol::Segment_offset_base offset_base
, bool only_if_ref
);
1830 // Define a symbol as a constant, sized version.
1833 do_define_as_constant(
1834 const char* name
, const char* version
, Defined
,
1835 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1836 typename
elfcpp::Elf_types
<size
>::Elf_WXword ssize
,
1837 elfcpp::STT type
, elfcpp::STB binding
,
1838 elfcpp::STV visibility
, unsigned char nonvis
,
1839 bool only_if_ref
, bool force_override
);
1841 // Add any undefined symbols named on the command line to the symbol
1842 // table, sized version.
1845 do_add_undefined_symbols_from_command_line(Layout
*);
1847 // Add one undefined symbol.
1850 add_undefined_symbol_from_command_line(const char* name
);
1852 // Types of common symbols.
1854 enum Commons_section_type
1862 // Allocate the common symbols, sized version.
1865 do_allocate_commons(Layout
*, Mapfile
*, Sort_commons_order
);
1867 // Allocate the common symbols from one list.
1870 do_allocate_commons_list(Layout
*, Commons_section_type
, Commons_type
*,
1871 Mapfile
*, Sort_commons_order
);
1873 // Returns all of the lines attached to LOC, not just the one the
1874 // instruction actually came from. This helps the ODR checker avoid
1876 static std::vector
<std::string
>
1877 linenos_from_loc(const Task
* task
, const Symbol_location
& loc
);
1879 // Implement detect_odr_violations.
1880 template<int size
, bool big_endian
>
1882 sized_detect_odr_violations() const;
1884 // Finalize symbols specialized for size.
1887 sized_finalize(off_t
, Stringpool
*, unsigned int*);
1889 // Finalize a symbol. Return whether it should be added to the
1893 sized_finalize_symbol(Symbol
*);
1895 // Add a symbol the final symtab by setting its index.
1898 add_to_final_symtab(Symbol
*, Stringpool
*, unsigned int* pindex
, off_t
* poff
);
1900 // Write globals specialized for size and endianness.
1901 template<int size
, bool big_endian
>
1903 sized_write_globals(const Stringpool
*, const Stringpool
*,
1904 Output_symtab_xindex
*, Output_symtab_xindex
*,
1905 Output_file
*) const;
1907 // Write out a symbol to P.
1908 template<int size
, bool big_endian
>
1910 sized_write_symbol(Sized_symbol
<size
>*,
1911 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1912 unsigned int shndx
, elfcpp::STB
,
1913 const Stringpool
*, unsigned char* p
) const;
1915 // Possibly warn about an undefined symbol from a dynamic object.
1917 warn_about_undefined_dynobj_symbol(Symbol
*) const;
1919 // Write out a section symbol, specialized for size and endianness.
1920 template<int size
, bool big_endian
>
1922 sized_write_section_symbol(const Output_section
*, Output_symtab_xindex
*,
1923 Output_file
*, off_t
) const;
1925 // The type of the list of symbols which have been forced local.
1926 typedef std::vector
<Symbol
*> Forced_locals
;
1928 // A map from symbols with COPY relocs to the dynamic objects where
1929 // they are defined.
1930 typedef Unordered_map
<const Symbol
*, Dynobj
*> Copied_symbol_dynobjs
;
1932 // We increment this every time we see a new undefined symbol, for
1933 // use in archive groups.
1934 size_t saw_undefined_
;
1935 // The index of the first global symbol in the output file.
1936 unsigned int first_global_index_
;
1937 // The file offset within the output symtab section where we should
1940 // The number of global symbols we want to write out.
1941 unsigned int output_count_
;
1942 // The file offset of the global dynamic symbols, or 0 if none.
1943 off_t dynamic_offset_
;
1944 // The index of the first global dynamic symbol (including
1945 // forced-local symbols).
1946 unsigned int first_dynamic_global_index_
;
1947 // The number of global dynamic symbols (including forced-local symbols),
1949 unsigned int dynamic_count_
;
1950 // The symbol hash table.
1951 Symbol_table_type table_
;
1952 // A pool of symbol names. This is used for all global symbols.
1953 // Entries in the hash table point into this pool.
1954 Stringpool namepool_
;
1955 // Forwarding symbols.
1956 Unordered_map
<const Symbol
*, Symbol
*> forwarders_
;
1957 // Weak aliases. A symbol in this list points to the next alias.
1958 // The aliases point to each other in a circular list.
1959 Unordered_map
<Symbol
*, Symbol
*> weak_aliases_
;
1960 // We don't expect there to be very many common symbols, so we keep
1961 // a list of them. When we find a common symbol we add it to this
1962 // list. It is possible that by the time we process the list the
1963 // symbol is no longer a common symbol. It may also have become a
1965 Commons_type commons_
;
1966 // This is like the commons_ field, except that it holds TLS common
1968 Commons_type tls_commons_
;
1969 // This is for small common symbols.
1970 Commons_type small_commons_
;
1971 // This is for large common symbols.
1972 Commons_type large_commons_
;
1973 // A list of symbols which have been forced to be local. We don't
1974 // expect there to be very many of them, so we keep a list of them
1975 // rather than walking the whole table to find them.
1976 Forced_locals forced_locals_
;
1977 // Manage symbol warnings.
1979 // Manage potential One Definition Rule (ODR) violations.
1980 Odr_map candidate_odr_violations_
;
1982 // When we emit a COPY reloc for a symbol, we define it in an
1983 // Output_data. When it's time to emit version information for it,
1984 // we need to know the dynamic object in which we found the original
1985 // definition. This maps symbols with COPY relocs to the dynamic
1986 // object where they were defined.
1987 Copied_symbol_dynobjs copied_symbol_dynobjs_
;
1988 // Information parsed from the version script, if any.
1989 const Version_script_info
& version_script_
;
1990 Garbage_collection
* gc_
;
1992 // Target-specific symbols, if any.
1993 std::vector
<Symbol
*> target_symbols_
;
1996 // We inline get_sized_symbol for efficiency.
2000 Symbol_table::get_sized_symbol(Symbol
* sym
) const
2002 gold_assert(size
== parameters
->target().get_size());
2003 return static_cast<Sized_symbol
<size
>*>(sym
);
2007 const Sized_symbol
<size
>*
2008 Symbol_table::get_sized_symbol(const Symbol
* sym
) const
2010 gold_assert(size
== parameters
->target().get_size());
2011 return static_cast<const Sized_symbol
<size
>*>(sym
);
2014 } // End namespace gold.
2016 #endif // !defined(GOLD_SYMTAB_H)