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.
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.
254 is_undef_binding_weak() const
255 { return this->undef_binding_weak_
; }
257 // Return the non-visibility part of the st_other field.
260 { return this->nonvis_
; }
262 // Set the non-visibility part of the st_other field.
264 set_nonvis(unsigned int nonvis
)
265 { this->nonvis_
= nonvis
; }
267 // Return whether this symbol is a forwarder. This will never be
268 // true of a symbol found in the hash table, but may be true of
269 // symbol pointers attached to object files.
272 { return this->is_forwarder_
; }
274 // Mark this symbol as a forwarder.
277 { this->is_forwarder_
= true; }
279 // Return whether this symbol has an alias in the weak aliases table
283 { return this->has_alias_
; }
285 // Mark this symbol as having an alias.
288 { this->has_alias_
= true; }
290 // Return whether this symbol needs an entry in the dynamic symbol
293 needs_dynsym_entry() const
295 return (this->needs_dynsym_entry_
298 && this->is_externally_visible()));
301 // Mark this symbol as needing an entry in the dynamic symbol table.
303 set_needs_dynsym_entry()
304 { this->needs_dynsym_entry_
= true; }
306 // Return whether this symbol should be added to the dynamic symbol
309 should_add_dynsym_entry(Symbol_table
*) const;
311 // Return whether this symbol has been seen in a regular object.
314 { return this->in_reg_
; }
316 // Mark this symbol as having been seen in a regular object.
319 { this->in_reg_
= true; }
321 // Return whether this symbol has been seen in a dynamic object.
324 { return this->in_dyn_
; }
326 // Mark this symbol as having been seen in a dynamic object.
329 { this->in_dyn_
= true; }
331 // Return whether this symbol has been seen in a real ELF object.
332 // (IN_REG will return TRUE if the symbol has been seen in either
333 // a real ELF object or an object claimed by a plugin.)
336 { return this->in_real_elf_
; }
338 // Mark this symbol as having been seen in a real ELF object.
341 { this->in_real_elf_
= true; }
343 // Return whether this symbol was defined in a section that was
344 // discarded from the link. This is used to control some error
347 is_defined_in_discarded_section() const
348 { return this->is_defined_in_discarded_section_
; }
350 // Mark this symbol as having been defined in a discarded section.
352 set_is_defined_in_discarded_section()
353 { this->is_defined_in_discarded_section_
= true; }
355 // Return the index of this symbol in the output file symbol table.
356 // A value of -1U means that this symbol is not going into the
357 // output file. This starts out as zero, and is set to a non-zero
358 // value by Symbol_table::finalize. It is an error to ask for the
359 // symbol table index before it has been set.
363 gold_assert(this->symtab_index_
!= 0);
364 return this->symtab_index_
;
367 // Set the index of the symbol in the output file symbol table.
369 set_symtab_index(unsigned int index
)
371 gold_assert(index
!= 0);
372 this->symtab_index_
= index
;
375 // Return whether this symbol already has an index in the output
376 // file symbol table.
378 has_symtab_index() const
379 { return this->symtab_index_
!= 0; }
381 // Return the index of this symbol in the dynamic symbol table. A
382 // value of -1U means that this symbol is not going into the dynamic
383 // symbol table. This starts out as zero, and is set to a non-zero
384 // during Layout::finalize. It is an error to ask for the dynamic
385 // symbol table index before it has been set.
389 gold_assert(this->dynsym_index_
!= 0);
390 return this->dynsym_index_
;
393 // Set the index of the symbol in the dynamic symbol table.
395 set_dynsym_index(unsigned int index
)
397 gold_assert(index
!= 0);
398 this->dynsym_index_
= index
;
401 // Return whether this symbol already has an index in the dynamic
404 has_dynsym_index() const
405 { return this->dynsym_index_
!= 0; }
407 // Return whether this symbol has an entry in the GOT section.
408 // For a TLS symbol, this GOT entry will hold its tp-relative offset.
410 has_got_offset(unsigned int got_type
) const
411 { return this->got_offsets_
.get_offset(got_type
) != -1U; }
413 // Return the offset into the GOT section of this symbol.
415 got_offset(unsigned int got_type
) const
417 unsigned int got_offset
= this->got_offsets_
.get_offset(got_type
);
418 gold_assert(got_offset
!= -1U);
422 // Set the GOT offset of this symbol.
424 set_got_offset(unsigned int got_type
, unsigned int got_offset
)
425 { this->got_offsets_
.set_offset(got_type
, got_offset
); }
427 // Return the GOT offset list.
428 const Got_offset_list
*
429 got_offset_list() const
430 { return this->got_offsets_
.get_list(); }
432 // Return whether this symbol has an entry in the PLT section.
434 has_plt_offset() const
435 { return this->plt_offset_
!= -1U; }
437 // Return the offset into the PLT section of this symbol.
441 gold_assert(this->has_plt_offset());
442 return this->plt_offset_
;
445 // Set the PLT offset of this symbol.
447 set_plt_offset(unsigned int plt_offset
)
449 gold_assert(plt_offset
!= -1U);
450 this->plt_offset_
= plt_offset
;
453 // Return whether this dynamic symbol needs a special value in the
454 // dynamic symbol table.
456 needs_dynsym_value() const
457 { return this->needs_dynsym_value_
; }
459 // Set that this dynamic symbol needs a special value in the dynamic
462 set_needs_dynsym_value()
464 gold_assert(this->object()->is_dynamic());
465 this->needs_dynsym_value_
= true;
468 // Return true if the final value of this symbol is known at link
471 final_value_is_known() const;
473 // Return true if SHNDX represents a common symbol. This depends on
476 is_common_shndx(unsigned int shndx
);
478 // Return whether this is a defined symbol (not undefined or
484 if (this->source_
!= FROM_OBJECT
)
485 return this->source_
!= IS_UNDEFINED
;
486 unsigned int shndx
= this->shndx(&is_ordinary
);
488 ? shndx
!= elfcpp::SHN_UNDEF
489 : !Symbol::is_common_shndx(shndx
));
492 // Return true if this symbol is from a dynamic object.
494 is_from_dynobj() const
496 return this->source_
== FROM_OBJECT
&& this->object()->is_dynamic();
499 // Return whether this is a placeholder symbol from a plugin object.
501 is_placeholder() const
503 return this->source_
== FROM_OBJECT
&& this->object()->pluginobj() != NULL
;
506 // Return whether this is an undefined symbol.
511 return ((this->source_
== FROM_OBJECT
512 && this->shndx(&is_ordinary
) == elfcpp::SHN_UNDEF
514 || this->source_
== IS_UNDEFINED
);
517 // Return whether this is a weak undefined symbol.
519 is_weak_undefined() const
520 { return this->is_undefined() && this->binding() == elfcpp::STB_WEAK
; }
522 // Return whether this is an absolute symbol.
527 return ((this->source_
== FROM_OBJECT
528 && this->shndx(&is_ordinary
) == elfcpp::SHN_ABS
530 || this->source_
== IS_CONSTANT
);
533 // Return whether this is a common symbol.
537 if (this->source_
!= FROM_OBJECT
)
539 if (this->type_
== elfcpp::STT_COMMON
)
542 unsigned int shndx
= this->shndx(&is_ordinary
);
543 return !is_ordinary
&& Symbol::is_common_shndx(shndx
);
546 // Return whether this symbol can be seen outside this object.
548 is_externally_visible() const
550 return ((this->visibility_
== elfcpp::STV_DEFAULT
551 || this->visibility_
== elfcpp::STV_PROTECTED
)
552 && !this->is_forced_local_
);
555 // Return true if this symbol can be preempted by a definition in
556 // another link unit.
558 is_preemptible() const
560 // It doesn't make sense to ask whether a symbol defined in
561 // another object is preemptible.
562 gold_assert(!this->is_from_dynobj());
564 // It doesn't make sense to ask whether an undefined symbol
566 gold_assert(!this->is_undefined());
568 // If a symbol does not have default visibility, it can not be
569 // seen outside this link unit and therefore is not preemptible.
570 if (this->visibility_
!= elfcpp::STV_DEFAULT
)
573 // If this symbol has been forced to be a local symbol by a
574 // version script, then it is not visible outside this link unit
575 // and is not preemptible.
576 if (this->is_forced_local_
)
579 // If we are not producing a shared library, then nothing is
581 if (!parameters
->options().shared())
584 // If the symbol was named in a --dynamic-list script, it is preemptible.
585 if (parameters
->options().in_dynamic_list(this->name()))
588 // If the user used -Bsymbolic or provided a --dynamic-list script,
589 // then nothing (else) is preemptible.
590 if (parameters
->options().Bsymbolic()
591 || parameters
->options().have_dynamic_list())
594 // If the user used -Bsymbolic-functions, then functions are not
595 // preemptible. We explicitly check for not being STT_OBJECT,
596 // rather than for being STT_FUNC, because that is what the GNU
598 if (this->type() != elfcpp::STT_OBJECT
599 && parameters
->options().Bsymbolic_functions())
602 // Otherwise the symbol is preemptible.
606 // Return true if this symbol is a function that needs a PLT entry.
608 needs_plt_entry() const
610 // An undefined symbol from an executable does not need a PLT entry.
611 if (this->is_undefined() && !parameters
->options().shared())
614 // An STT_GNU_IFUNC symbol always needs a PLT entry, even when
615 // doing a static link.
616 if (this->type() == elfcpp::STT_GNU_IFUNC
)
619 // We only need a PLT entry for a function.
620 if (!this->is_func())
623 // If we're doing a static link or a -pie link, we don't create
625 if (parameters
->doing_static_link()
626 || parameters
->options().pie())
629 // We need a PLT entry if the function is defined in a dynamic
630 // object, or is undefined when building a shared object, or if it
631 // is subject to pre-emption.
632 return (this->is_from_dynobj()
633 || this->is_undefined()
634 || this->is_preemptible());
637 // When determining whether a reference to a symbol needs a dynamic
638 // relocation, we need to know several things about the reference.
639 // These flags may be or'ed together. 0 means that the symbol
640 // isn't referenced at all.
643 // A reference to the symbol's absolute address. This includes
644 // references that cause an absolute address to be stored in the GOT.
646 // A reference that calculates the offset of the symbol from some
647 // anchor point, such as the PC or GOT.
649 // A TLS-related reference.
651 // A reference that can always be treated as a function call.
653 // When set, says that dynamic relocations are needed even if a
654 // symbol has a plt entry.
658 // Given a direct absolute or pc-relative static relocation against
659 // the global symbol, this function returns whether a dynamic relocation
663 needs_dynamic_reloc(int flags
) const
665 // No dynamic relocations in a static link!
666 if (parameters
->doing_static_link())
669 // A reference to an undefined symbol from an executable should be
670 // statically resolved to 0, and does not need a dynamic relocation.
671 // This matches gnu ld behavior.
672 if (this->is_undefined() && !parameters
->options().shared())
675 // A reference to an absolute symbol does not need a dynamic relocation.
676 if (this->is_absolute())
679 // An absolute reference within a position-independent output file
680 // will need a dynamic relocation.
681 if ((flags
& ABSOLUTE_REF
)
682 && parameters
->options().output_is_position_independent())
685 // A function call that can branch to a local PLT entry does not need
686 // a dynamic relocation.
687 if ((flags
& FUNCTION_CALL
) && this->has_plt_offset())
690 // A reference to any PLT entry in a non-position-independent executable
691 // does not need a dynamic relocation.
692 if (!(flags
& FUNC_DESC_ABI
)
693 && !parameters
->options().output_is_position_independent()
694 && this->has_plt_offset())
697 // A reference to a symbol defined in a dynamic object or to a
698 // symbol that is preemptible will need a dynamic relocation.
699 if (this->is_from_dynobj()
700 || this->is_undefined()
701 || this->is_preemptible())
704 // For all other cases, return FALSE.
708 // Whether we should use the PLT offset associated with a symbol for
709 // a relocation. FLAGS is a set of Reference_flags.
712 use_plt_offset(int flags
) const
714 // If the symbol doesn't have a PLT offset, then naturally we
715 // don't want to use it.
716 if (!this->has_plt_offset())
719 // For a STT_GNU_IFUNC symbol we always have to use the PLT entry.
720 if (this->type() == elfcpp::STT_GNU_IFUNC
)
723 // If we are going to generate a dynamic relocation, then we will
724 // wind up using that, so no need to use the PLT entry.
725 if (this->needs_dynamic_reloc(flags
))
728 // If the symbol is from a dynamic object, we need to use the PLT
730 if (this->is_from_dynobj())
733 // If we are generating a shared object, and this symbol is
734 // undefined or preemptible, we need to use the PLT entry.
735 if (parameters
->options().shared()
736 && (this->is_undefined() || this->is_preemptible()))
739 // If this is a call to a weak undefined symbol, we need to use
740 // the PLT entry; the symbol may be defined by a library loaded
742 if ((flags
& FUNCTION_CALL
) && this->is_weak_undefined())
745 // Otherwise we can use the regular definition.
749 // Given a direct absolute static relocation against
750 // the global symbol, where a dynamic relocation is needed, this
751 // function returns whether a relative dynamic relocation can be used.
752 // The caller must determine separately whether the static relocation
753 // is compatible with a relative relocation.
756 can_use_relative_reloc(bool is_function_call
) const
758 // A function call that can branch to a local PLT entry can
759 // use a RELATIVE relocation.
760 if (is_function_call
&& this->has_plt_offset())
763 // A reference to a symbol defined in a dynamic object or to a
764 // symbol that is preemptible can not use a RELATIVE relocation.
765 if (this->is_from_dynobj()
766 || this->is_undefined()
767 || this->is_preemptible())
770 // For all other cases, return TRUE.
774 // Return the output section where this symbol is defined. Return
775 // NULL if the symbol has an absolute value.
777 output_section() const;
779 // Set the symbol's output section. This is used for symbols
780 // defined in scripts. This should only be called after the symbol
781 // table has been finalized.
783 set_output_section(Output_section
*);
785 // Return whether there should be a warning for references to this
789 { return this->has_warning_
; }
791 // Mark this symbol as having a warning.
794 { this->has_warning_
= true; }
796 // Return whether this symbol is defined by a COPY reloc from a
799 is_copied_from_dynobj() const
800 { return this->is_copied_from_dynobj_
; }
802 // Mark this symbol as defined by a COPY reloc.
804 set_is_copied_from_dynobj()
805 { this->is_copied_from_dynobj_
= true; }
807 // Return whether this symbol is forced to visibility STB_LOCAL
808 // by a "local:" entry in a version script.
810 is_forced_local() const
811 { return this->is_forced_local_
; }
813 // Mark this symbol as forced to STB_LOCAL visibility.
815 set_is_forced_local()
816 { this->is_forced_local_
= true; }
818 // Return true if this may need a COPY relocation.
819 // References from an executable object to non-function symbols
820 // defined in a dynamic object may need a COPY relocation.
822 may_need_copy_reloc() const
824 return (!parameters
->options().output_is_position_independent()
825 && parameters
->options().copyreloc()
826 && this->is_from_dynobj()
827 && !this->is_func());
830 // Return true if this symbol was predefined by the linker.
832 is_predefined() const
833 { return this->is_predefined_
; }
835 // Return true if this is a C++ vtable symbol.
837 is_cxx_vtable() const
838 { return is_prefix_of("_ZTV", this->name_
); }
841 // Instances of this class should always be created at a specific
844 { memset(this, 0, sizeof *this); }
846 // Initialize the general fields.
848 init_fields(const char* name
, const char* version
,
849 elfcpp::STT type
, elfcpp::STB binding
,
850 elfcpp::STV visibility
, unsigned char nonvis
);
852 // Initialize fields from an ELF symbol in OBJECT. ST_SHNDX is the
853 // section index, IS_ORDINARY is whether it is a normal section
854 // index rather than a special code.
855 template<int size
, bool big_endian
>
857 init_base_object(const char* name
, const char* version
, Object
* object
,
858 const elfcpp::Sym
<size
, big_endian
>&, unsigned int st_shndx
,
861 // Initialize fields for an Output_data.
863 init_base_output_data(const char* name
, const char* version
, Output_data
*,
864 elfcpp::STT
, elfcpp::STB
, elfcpp::STV
,
865 unsigned char nonvis
, bool offset_is_from_end
,
868 // Initialize fields for an Output_segment.
870 init_base_output_segment(const char* name
, const char* version
,
871 Output_segment
* os
, elfcpp::STT type
,
872 elfcpp::STB binding
, elfcpp::STV visibility
,
873 unsigned char nonvis
,
874 Segment_offset_base offset_base
,
877 // Initialize fields for a constant.
879 init_base_constant(const char* name
, const char* version
, elfcpp::STT type
,
880 elfcpp::STB binding
, elfcpp::STV visibility
,
881 unsigned char nonvis
, bool is_predefined
);
883 // Initialize fields for an undefined symbol.
885 init_base_undefined(const char* name
, const char* version
, elfcpp::STT type
,
886 elfcpp::STB binding
, elfcpp::STV visibility
,
887 unsigned char nonvis
);
889 // Override existing symbol.
890 template<int size
, bool big_endian
>
892 override_base(const elfcpp::Sym
<size
, big_endian
>&, unsigned int st_shndx
,
893 bool is_ordinary
, Object
* object
, const char* version
);
895 // Override existing symbol with a special symbol.
897 override_base_with_special(const Symbol
* from
);
899 // Override symbol version.
901 override_version(const char* version
);
903 // Allocate a common symbol by giving it a location in the output
906 allocate_base_common(Output_data
*);
909 Symbol(const Symbol
&);
910 Symbol
& operator=(const Symbol
&);
912 // Symbol name (expected to point into a Stringpool).
914 // Symbol version (expected to point into a Stringpool). This may
916 const char* version_
;
920 // This struct is used if SOURCE_ == FROM_OBJECT.
923 // Object in which symbol is defined, or in which it was first
926 // Section number in object_ in which symbol is defined.
930 // This struct is used if SOURCE_ == IN_OUTPUT_DATA.
933 // Output_data in which symbol is defined. Before
934 // Layout::finalize the symbol's value is an offset within the
936 Output_data
* output_data
;
937 // True if the offset is from the end, false if the offset is
938 // from the beginning.
939 bool offset_is_from_end
;
942 // This struct is used if SOURCE_ == IN_OUTPUT_SEGMENT.
945 // Output_segment in which the symbol is defined. Before
946 // Layout::finalize the symbol's value is an offset.
947 Output_segment
* output_segment
;
948 // The base to use for the offset before Layout::finalize.
949 Segment_offset_base offset_base
;
953 // The index of this symbol in the output file. If the symbol is
954 // not going into the output file, this value is -1U. This field
955 // starts as always holding zero. It is set to a non-zero value by
956 // Symbol_table::finalize.
957 unsigned int symtab_index_
;
959 // The index of this symbol in the dynamic symbol table. If the
960 // symbol is not going into the dynamic symbol table, this value is
961 // -1U. This field starts as always holding zero. It is set to a
962 // non-zero value during Layout::finalize.
963 unsigned int dynsym_index_
;
965 // The GOT section entries for this symbol. A symbol may have more
966 // than one GOT offset (e.g., when mixing modules compiled with two
967 // different TLS models), but will usually have at most one.
968 Got_offset_list got_offsets_
;
970 // If this symbol has an entry in the PLT section, then this is the
971 // offset from the start of the PLT section. This is -1U if there
973 unsigned int plt_offset_
;
975 // Symbol type (bits 0 to 3).
976 elfcpp::STT type_
: 4;
977 // Symbol binding (bits 4 to 7).
978 elfcpp::STB binding_
: 4;
979 // Symbol visibility (bits 8 to 9).
980 elfcpp::STV visibility_
: 2;
981 // Rest of symbol st_other field (bits 10 to 15).
982 unsigned int nonvis_
: 6;
983 // The type of symbol (bits 16 to 18).
985 // True if this is the default version of the symbol (bit 19).
987 // True if this symbol really forwards to another symbol. This is
988 // used when we discover after the fact that two different entries
989 // in the hash table really refer to the same symbol. This will
990 // never be set for a symbol found in the hash table, but may be set
991 // for a symbol found in the list of symbols attached to an Object.
992 // It forwards to the symbol found in the forwarders_ map of
993 // Symbol_table (bit 20).
994 bool is_forwarder_
: 1;
995 // True if the symbol has an alias in the weak_aliases table in
996 // Symbol_table (bit 21).
998 // True if this symbol needs to be in the dynamic symbol table (bit
1000 bool needs_dynsym_entry_
: 1;
1001 // True if we've seen this symbol in a regular object (bit 23).
1003 // True if we've seen this symbol in a dynamic object (bit 24).
1005 // True if this is a dynamic symbol which needs a special value in
1006 // the dynamic symbol table (bit 25).
1007 bool needs_dynsym_value_
: 1;
1008 // True if there is a warning for this symbol (bit 26).
1009 bool has_warning_
: 1;
1010 // True if we are using a COPY reloc for this symbol, so that the
1011 // real definition lives in a dynamic object (bit 27).
1012 bool is_copied_from_dynobj_
: 1;
1013 // True if this symbol was forced to local visibility by a version
1015 bool is_forced_local_
: 1;
1016 // True if the field u_.from_object.shndx is an ordinary section
1017 // index, not one of the special codes from SHN_LORESERVE to
1018 // SHN_HIRESERVE (bit 29).
1019 bool is_ordinary_shndx_
: 1;
1020 // True if we've seen this symbol in a "real" ELF object (bit 30).
1021 // If the symbol has been seen in a relocatable, non-IR, object file,
1022 // it's known to be referenced from outside the IR. A reference from
1023 // a dynamic object doesn't count as a "real" ELF, and we'll simply
1024 // mark the symbol as "visible" from outside the IR. The compiler
1025 // can use this distinction to guide its handling of COMDAT symbols.
1026 bool in_real_elf_
: 1;
1027 // True if this symbol is defined in a section which was discarded
1029 bool is_defined_in_discarded_section_
: 1;
1030 // True if UNDEF_BINDING_WEAK_ has been set (bit 32).
1031 bool undef_binding_set_
: 1;
1032 // True if this symbol was a weak undef resolved by a dynamic def
1034 bool undef_binding_weak_
: 1;
1035 // True if this symbol is a predefined linker symbol (bit 34).
1036 bool is_predefined_
: 1;
1039 // The parts of a symbol which are size specific. Using a template
1040 // derived class like this helps us use less space on a 32-bit system.
1043 class Sized_symbol
: public Symbol
1046 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Value_type
;
1047 typedef typename
elfcpp::Elf_types
<size
>::Elf_WXword Size_type
;
1052 // Initialize fields from an ELF symbol in OBJECT. ST_SHNDX is the
1053 // section index, IS_ORDINARY is whether it is a normal section
1054 // index rather than a special code.
1055 template<bool big_endian
>
1057 init_object(const char* name
, const char* version
, Object
* object
,
1058 const elfcpp::Sym
<size
, big_endian
>&, unsigned int st_shndx
,
1061 // Initialize fields for an Output_data.
1063 init_output_data(const char* name
, const char* version
, Output_data
*,
1064 Value_type value
, Size_type symsize
, elfcpp::STT
,
1065 elfcpp::STB
, elfcpp::STV
, unsigned char nonvis
,
1066 bool offset_is_from_end
, bool is_predefined
);
1068 // Initialize fields for an Output_segment.
1070 init_output_segment(const char* name
, const char* version
, Output_segment
*,
1071 Value_type value
, Size_type symsize
, elfcpp::STT
,
1072 elfcpp::STB
, elfcpp::STV
, unsigned char nonvis
,
1073 Segment_offset_base offset_base
, bool is_predefined
);
1075 // Initialize fields for a constant.
1077 init_constant(const char* name
, const char* version
, Value_type value
,
1078 Size_type symsize
, elfcpp::STT
, elfcpp::STB
, elfcpp::STV
,
1079 unsigned char nonvis
, bool is_predefined
);
1081 // Initialize fields for an undefined symbol.
1083 init_undefined(const char* name
, const char* version
, elfcpp::STT
,
1084 elfcpp::STB
, elfcpp::STV
, unsigned char nonvis
);
1086 // Override existing symbol.
1087 template<bool big_endian
>
1089 override(const elfcpp::Sym
<size
, big_endian
>&, unsigned int st_shndx
,
1090 bool is_ordinary
, Object
* object
, const char* version
);
1092 // Override existing symbol with a special symbol.
1094 override_with_special(const Sized_symbol
<size
>*);
1096 // Return the symbol's value.
1099 { return this->value_
; }
1101 // Return the symbol's size (we can't call this 'size' because that
1102 // is a template parameter).
1105 { return this->symsize_
; }
1107 // Set the symbol size. This is used when resolving common symbols.
1109 set_symsize(Size_type symsize
)
1110 { this->symsize_
= symsize
; }
1112 // Set the symbol value. This is called when we store the final
1113 // values of the symbols into the symbol table.
1115 set_value(Value_type value
)
1116 { this->value_
= value
; }
1118 // Allocate a common symbol by giving it a location in the output
1121 allocate_common(Output_data
*, Value_type value
);
1124 Sized_symbol(const Sized_symbol
&);
1125 Sized_symbol
& operator=(const Sized_symbol
&);
1127 // Symbol value. Before Layout::finalize this is the offset in the
1128 // input section. This is set to the final value during
1129 // Layout::finalize.
1135 // A struct describing a symbol defined by the linker, where the value
1136 // of the symbol is defined based on an output section. This is used
1137 // for symbols defined by the linker, like "_init_array_start".
1139 struct Define_symbol_in_section
1143 // The name of the output section with which this symbol should be
1144 // associated. If there is no output section with that name, the
1145 // symbol will be defined as zero.
1146 const char* output_section
;
1147 // The offset of the symbol within the output section. This is an
1148 // offset from the start of the output section, unless start_at_end
1149 // is true, in which case this is an offset from the end of the
1152 // The size of the symbol.
1156 // The symbol binding.
1157 elfcpp::STB binding
;
1158 // The symbol visibility.
1159 elfcpp::STV visibility
;
1160 // The rest of the st_other field.
1161 unsigned char nonvis
;
1162 // If true, the value field is an offset from the end of the output
1164 bool offset_is_from_end
;
1165 // If true, this symbol is defined only if we see a reference to it.
1169 // A struct describing a symbol defined by the linker, where the value
1170 // of the symbol is defined based on a segment. This is used for
1171 // symbols defined by the linker, like "_end". We describe the
1172 // segment with which the symbol should be associated by its
1173 // characteristics. If no segment meets these characteristics, the
1174 // symbol will be defined as zero. If there is more than one segment
1175 // which meets these characteristics, we will use the first one.
1177 struct Define_symbol_in_segment
1181 // The segment type where the symbol should be defined, typically
1183 elfcpp::PT segment_type
;
1184 // Bitmask of segment flags which must be set.
1185 elfcpp::PF segment_flags_set
;
1186 // Bitmask of segment flags which must be clear.
1187 elfcpp::PF segment_flags_clear
;
1188 // The offset of the symbol within the segment. The offset is
1189 // calculated from the position set by offset_base.
1191 // The size of the symbol.
1195 // The symbol binding.
1196 elfcpp::STB binding
;
1197 // The symbol visibility.
1198 elfcpp::STV visibility
;
1199 // The rest of the st_other field.
1200 unsigned char nonvis
;
1201 // The base from which we compute the offset.
1202 Symbol::Segment_offset_base offset_base
;
1203 // If true, this symbol is defined only if we see a reference to it.
1207 // Specify an object/section/offset location. Used by ODR code.
1209 struct Symbol_location
1211 // Object where the symbol is defined.
1213 // Section-in-object where the symbol is defined.
1215 // For relocatable objects, offset-in-section where the symbol is defined.
1216 // For dynamic objects, address where the symbol is defined.
1218 bool operator==(const Symbol_location
& that
) const
1220 return (this->object
== that
.object
1221 && this->shndx
== that
.shndx
1222 && this->offset
== that
.offset
);
1226 // This class manages warnings. Warnings are a GNU extension. When
1227 // we see a section named .gnu.warning.SYM in an object file, and if
1228 // we wind using the definition of SYM from that object file, then we
1229 // will issue a warning for any relocation against SYM from a
1230 // different object file. The text of the warning is the contents of
1231 // the section. This is not precisely the definition used by the old
1232 // GNU linker; the old GNU linker treated an occurrence of
1233 // .gnu.warning.SYM as defining a warning symbol. A warning symbol
1234 // would trigger a warning on any reference. However, it was
1235 // inconsistent in that a warning in a dynamic object only triggered
1236 // if there was no definition in a regular object. This linker is
1237 // different in that we only issue a warning if we use the symbol
1238 // definition from the same object file as the warning section.
1247 // Add a warning for symbol NAME in object OBJ. WARNING is the text
1250 add_warning(Symbol_table
* symtab
, const char* name
, Object
* obj
,
1251 const std::string
& warning
);
1253 // For each symbol for which we should give a warning, make a note
1256 note_warnings(Symbol_table
* symtab
);
1258 // Issue a warning for a reference to SYM at RELINFO's location.
1259 template<int size
, bool big_endian
>
1261 issue_warning(const Symbol
* sym
, const Relocate_info
<size
, big_endian
>*,
1262 size_t relnum
, off_t reloffset
) const;
1265 Warnings(const Warnings
&);
1266 Warnings
& operator=(const Warnings
&);
1268 // What we need to know to get the warning text.
1269 struct Warning_location
1271 // The object the warning is in.
1273 // The warning text.
1277 : object(NULL
), text()
1281 set(Object
* o
, const std::string
& t
)
1288 // A mapping from warning symbol names (canonicalized in
1289 // Symbol_table's namepool_ field) to warning information.
1290 typedef Unordered_map
<const char*, Warning_location
> Warning_table
;
1292 Warning_table warnings_
;
1295 // The main linker symbol table.
1300 // The different places where a symbol definition can come from.
1303 // Defined in an object file--the normal case.
1305 // Defined for a COPY reloc.
1307 // Defined on the command line using --defsym.
1309 // Defined (so to speak) on the command line using -u.
1311 // Defined in a linker script.
1313 // Predefined by the linker.
1315 // Defined by the linker during an incremental base link, but not
1316 // a predefined symbol (e.g., common, defined in script).
1320 // The order in which we sort common symbols.
1321 enum Sort_commons_order
1323 SORT_COMMONS_BY_SIZE_DESCENDING
,
1324 SORT_COMMONS_BY_ALIGNMENT_DESCENDING
,
1325 SORT_COMMONS_BY_ALIGNMENT_ASCENDING
1328 // COUNT is an estimate of how many symbols will be inserted in the
1329 // symbol table. It's ok to put 0 if you don't know; a correct
1330 // guess will just save some CPU by reducing hashtable resizes.
1331 Symbol_table(unsigned int count
, const Version_script_info
& version_script
);
1337 { this->icf_
= icf
;}
1341 { return this->icf_
; }
1343 // Returns true if ICF determined that this is a duplicate section.
1345 is_section_folded(Object
* obj
, unsigned int shndx
) const;
1348 set_gc(Garbage_collection
* gc
)
1353 { return this->gc_
; }
1355 // During garbage collection, this keeps undefined symbols.
1357 gc_mark_undef_symbols(Layout
*);
1359 // This tells garbage collection that this symbol is referenced.
1361 gc_mark_symbol(Symbol
* sym
);
1363 // During garbage collection, this keeps sections that correspond to
1364 // symbols seen in dynamic objects.
1366 gc_mark_dyn_syms(Symbol
* sym
);
1368 // Add COUNT external symbols from the relocatable object RELOBJ to
1369 // the symbol table. SYMS is the symbols, SYMNDX_OFFSET is the
1370 // offset in the symbol table of the first symbol, SYM_NAMES is
1371 // their names, SYM_NAME_SIZE is the size of SYM_NAMES. This sets
1372 // SYMPOINTERS to point to the symbols in the symbol table. It sets
1373 // *DEFINED to the number of defined symbols.
1374 template<int size
, bool big_endian
>
1376 add_from_relobj(Sized_relobj_file
<size
, big_endian
>* relobj
,
1377 const unsigned char* syms
, size_t count
,
1378 size_t symndx_offset
, const char* sym_names
,
1379 size_t sym_name_size
,
1380 typename Sized_relobj_file
<size
, big_endian
>::Symbols
*,
1383 // Add one external symbol from the plugin object OBJ to the symbol table.
1384 // Returns a pointer to the resolved symbol in the symbol table.
1385 template<int size
, bool big_endian
>
1387 add_from_pluginobj(Sized_pluginobj
<size
, big_endian
>* obj
,
1388 const char* name
, const char* ver
,
1389 elfcpp::Sym
<size
, big_endian
>* sym
);
1391 // Add COUNT dynamic symbols from the dynamic object DYNOBJ to the
1392 // symbol table. SYMS is the symbols. SYM_NAMES is their names.
1393 // SYM_NAME_SIZE is the size of SYM_NAMES. The other parameters are
1394 // symbol version data.
1395 template<int size
, bool big_endian
>
1397 add_from_dynobj(Sized_dynobj
<size
, big_endian
>* dynobj
,
1398 const unsigned char* syms
, size_t count
,
1399 const char* sym_names
, size_t sym_name_size
,
1400 const unsigned char* versym
, size_t versym_size
,
1401 const std::vector
<const char*>*,
1402 typename Sized_relobj_file
<size
, big_endian
>::Symbols
*,
1405 // Add one external symbol from the incremental object OBJ to the symbol
1406 // table. Returns a pointer to the resolved symbol in the symbol table.
1407 template<int size
, bool big_endian
>
1409 add_from_incrobj(Object
* obj
, const char* name
,
1410 const char* ver
, elfcpp::Sym
<size
, big_endian
>* sym
);
1412 // Define a special symbol based on an Output_data. It is a
1413 // multiple definition error if this symbol is already defined.
1415 define_in_output_data(const char* name
, const char* version
, Defined
,
1416 Output_data
*, uint64_t value
, uint64_t symsize
,
1417 elfcpp::STT type
, elfcpp::STB binding
,
1418 elfcpp::STV visibility
, unsigned char nonvis
,
1419 bool offset_is_from_end
, bool only_if_ref
);
1421 // Define a special symbol based on an Output_segment. It is a
1422 // multiple definition error if this symbol is already defined.
1424 define_in_output_segment(const char* name
, const char* version
, Defined
,
1425 Output_segment
*, uint64_t value
, uint64_t symsize
,
1426 elfcpp::STT type
, elfcpp::STB binding
,
1427 elfcpp::STV visibility
, unsigned char nonvis
,
1428 Symbol::Segment_offset_base
, bool only_if_ref
);
1430 // Define a special symbol with a constant value. It is a multiple
1431 // definition error if this symbol is already defined.
1433 define_as_constant(const char* name
, const char* version
, Defined
,
1434 uint64_t value
, uint64_t symsize
, elfcpp::STT type
,
1435 elfcpp::STB binding
, elfcpp::STV visibility
,
1436 unsigned char nonvis
, bool only_if_ref
,
1437 bool force_override
);
1439 // Define a set of symbols in output sections. If ONLY_IF_REF is
1440 // true, only define them if they are referenced.
1442 define_symbols(const Layout
*, int count
, const Define_symbol_in_section
*,
1445 // Define a set of symbols in output segments. If ONLY_IF_REF is
1446 // true, only defined them if they are referenced.
1448 define_symbols(const Layout
*, int count
, const Define_symbol_in_segment
*,
1451 // Define SYM using a COPY reloc. POSD is the Output_data where the
1452 // symbol should be defined--typically a .dyn.bss section. VALUE is
1453 // the offset within POSD.
1456 define_with_copy_reloc(Sized_symbol
<size
>* sym
, Output_data
* posd
,
1457 typename
elfcpp::Elf_types
<size
>::Elf_Addr
);
1459 // Look up a symbol.
1461 lookup(const char*, const char* version
= NULL
) const;
1463 // Return the real symbol associated with the forwarder symbol FROM.
1465 resolve_forwards(const Symbol
* from
) const;
1467 // Return the sized version of a symbol in this table.
1470 get_sized_symbol(Symbol
*) const;
1473 const Sized_symbol
<size
>*
1474 get_sized_symbol(const Symbol
*) const;
1476 // Return the count of undefined symbols seen.
1478 saw_undefined() const
1479 { return this->saw_undefined_
; }
1481 // Allocate the common symbols
1483 allocate_commons(Layout
*, Mapfile
*);
1485 // Add a warning for symbol NAME in object OBJ. WARNING is the text
1488 add_warning(const char* name
, Object
* obj
, const std::string
& warning
)
1489 { this->warnings_
.add_warning(this, name
, obj
, warning
); }
1491 // Canonicalize a symbol name for use in the hash table.
1493 canonicalize_name(const char* name
)
1494 { return this->namepool_
.add(name
, true, NULL
); }
1496 // Possibly issue a warning for a reference to SYM at LOCATION which
1498 template<int size
, bool big_endian
>
1500 issue_warning(const Symbol
* sym
,
1501 const Relocate_info
<size
, big_endian
>* relinfo
,
1502 size_t relnum
, off_t reloffset
) const
1503 { this->warnings_
.issue_warning(sym
, relinfo
, relnum
, reloffset
); }
1505 // Check candidate_odr_violations_ to find symbols with the same name
1506 // but apparently different definitions (different source-file/line-no).
1508 detect_odr_violations(const Task
*, const char* output_file_name
) const;
1510 // Add any undefined symbols named on the command line to the symbol
1513 add_undefined_symbols_from_command_line(Layout
*);
1515 // SYM is defined using a COPY reloc. Return the dynamic object
1516 // where the original definition was found.
1518 get_copy_source(const Symbol
* sym
) const;
1520 // Set the dynamic symbol indexes. INDEX is the index of the first
1521 // global dynamic symbol. Pointers to the symbols are stored into
1522 // the vector. The names are stored into the Stringpool. This
1523 // returns an updated dynamic symbol index.
1525 set_dynsym_indexes(unsigned int index
, std::vector
<Symbol
*>*,
1526 Stringpool
*, Versions
*);
1528 // Finalize the symbol table after we have set the final addresses
1529 // of all the input sections. This sets the final symbol indexes,
1530 // values and adds the names to *POOL. *PLOCAL_SYMCOUNT is the
1531 // index of the first global symbol. OFF is the file offset of the
1532 // global symbol table, DYNOFF is the offset of the globals in the
1533 // dynamic symbol table, DYN_GLOBAL_INDEX is the index of the first
1534 // global dynamic symbol, and DYNCOUNT is the number of global
1535 // dynamic symbols. This records the parameters, and returns the
1536 // new file offset. It updates *PLOCAL_SYMCOUNT if it created any
1539 finalize(off_t off
, off_t dynoff
, size_t dyn_global_index
, size_t dyncount
,
1540 Stringpool
* pool
, unsigned int* plocal_symcount
);
1542 // Set the final file offset of the symbol table.
1544 set_file_offset(off_t off
)
1545 { this->offset_
= off
; }
1547 // Status code of Symbol_table::compute_final_value.
1548 enum Compute_final_value_status
1552 // Unsupported symbol section.
1553 CFVS_UNSUPPORTED_SYMBOL_SECTION
,
1554 // No output section.
1555 CFVS_NO_OUTPUT_SECTION
1558 // Compute the final value of SYM and store status in location PSTATUS.
1559 // During relaxation, this may be called multiple times for a symbol to
1560 // compute its would-be final value in each relaxation pass.
1563 typename Sized_symbol
<size
>::Value_type
1564 compute_final_value(const Sized_symbol
<size
>* sym
,
1565 Compute_final_value_status
* pstatus
) const;
1567 // Return the index of the first global symbol.
1569 first_global_index() const
1570 { return this->first_global_index_
; }
1572 // Return the total number of symbols in the symbol table.
1574 output_count() const
1575 { return this->output_count_
; }
1577 // Write out the global symbols.
1579 write_globals(const Stringpool
*, const Stringpool
*,
1580 Output_symtab_xindex
*, Output_symtab_xindex
*,
1581 Output_file
*) const;
1583 // Write out a section symbol. Return the updated offset.
1585 write_section_symbol(const Output_section
*, Output_symtab_xindex
*,
1586 Output_file
*, off_t
) const;
1588 // Loop over all symbols, applying the function F to each.
1589 template<int size
, typename F
>
1591 for_all_symbols(F f
) const
1593 for (Symbol_table_type::const_iterator p
= this->table_
.begin();
1594 p
!= this->table_
.end();
1597 Sized_symbol
<size
>* sym
= static_cast<Sized_symbol
<size
>*>(p
->second
);
1602 // Dump statistical information to stderr.
1604 print_stats() const;
1606 // Return the version script information.
1607 const Version_script_info
&
1608 version_script() const
1609 { return version_script_
; }
1612 Symbol_table(const Symbol_table
&);
1613 Symbol_table
& operator=(const Symbol_table
&);
1615 // The type of the list of common symbols.
1616 typedef std::vector
<Symbol
*> Commons_type
;
1618 // The type of the symbol hash table.
1620 typedef std::pair
<Stringpool::Key
, Stringpool::Key
> Symbol_table_key
;
1622 // The hash function. The key values are Stringpool keys.
1623 struct Symbol_table_hash
1626 operator()(const Symbol_table_key
& key
) const
1628 return key
.first
^ key
.second
;
1632 struct Symbol_table_eq
1635 operator()(const Symbol_table_key
&, const Symbol_table_key
&) const;
1638 typedef Unordered_map
<Symbol_table_key
, Symbol
*, Symbol_table_hash
,
1639 Symbol_table_eq
> Symbol_table_type
;
1641 // A map from symbol name (as a pointer into the namepool) to all
1642 // the locations the symbols is (weakly) defined (and certain other
1643 // conditions are met). This map will be used later to detect
1644 // possible One Definition Rule (ODR) violations.
1645 struct Symbol_location_hash
1647 size_t operator()(const Symbol_location
& loc
) const
1648 { return reinterpret_cast<uintptr_t>(loc
.object
) ^ loc
.offset
^ loc
.shndx
; }
1651 typedef Unordered_map
<const char*,
1652 Unordered_set
<Symbol_location
, Symbol_location_hash
> >
1655 // Make FROM a forwarder symbol to TO.
1657 make_forwarder(Symbol
* from
, Symbol
* to
);
1660 template<int size
, bool big_endian
>
1662 add_from_object(Object
*, const char* name
, Stringpool::Key name_key
,
1663 const char* version
, Stringpool::Key version_key
,
1664 bool def
, const elfcpp::Sym
<size
, big_endian
>& sym
,
1665 unsigned int st_shndx
, bool is_ordinary
,
1666 unsigned int orig_st_shndx
);
1668 // Define a default symbol.
1669 template<int size
, bool big_endian
>
1671 define_default_version(Sized_symbol
<size
>*, bool,
1672 Symbol_table_type::iterator
);
1675 template<int size
, bool big_endian
>
1677 resolve(Sized_symbol
<size
>* to
,
1678 const elfcpp::Sym
<size
, big_endian
>& sym
,
1679 unsigned int st_shndx
, bool is_ordinary
,
1680 unsigned int orig_st_shndx
,
1681 Object
*, const char* version
);
1683 template<int size
, bool big_endian
>
1685 resolve(Sized_symbol
<size
>* to
, const Sized_symbol
<size
>* from
);
1687 // Record that a symbol is forced to be local by a version script or
1690 force_local(Symbol
*);
1692 // Adjust NAME and *NAME_KEY for wrapping.
1694 wrap_symbol(const char* name
, Stringpool::Key
* name_key
);
1696 // Whether we should override a symbol, based on flags in
1699 should_override(const Symbol
*, unsigned int, elfcpp::STT
, Defined
,
1700 Object
*, bool*, bool*);
1702 // Report a problem in symbol resolution.
1704 report_resolve_problem(bool is_error
, const char* msg
, const Symbol
* to
,
1705 Defined
, Object
* object
);
1707 // Override a symbol.
1708 template<int size
, bool big_endian
>
1710 override(Sized_symbol
<size
>* tosym
,
1711 const elfcpp::Sym
<size
, big_endian
>& fromsym
,
1712 unsigned int st_shndx
, bool is_ordinary
,
1713 Object
* object
, const char* version
);
1715 // Whether we should override a symbol with a special symbol which
1716 // is automatically defined by the linker.
1718 should_override_with_special(const Symbol
*, elfcpp::STT
, Defined
);
1720 // Override a symbol with a special symbol.
1723 override_with_special(Sized_symbol
<size
>* tosym
,
1724 const Sized_symbol
<size
>* fromsym
);
1726 // Record all weak alias sets for a dynamic object.
1729 record_weak_aliases(std::vector
<Sized_symbol
<size
>*>*);
1731 // Define a special symbol.
1732 template<int size
, bool big_endian
>
1734 define_special_symbol(const char** pname
, const char** pversion
,
1735 bool only_if_ref
, Sized_symbol
<size
>** poldsym
,
1736 bool* resolve_oldsym
);
1738 // Define a symbol in an Output_data, sized version.
1741 do_define_in_output_data(const char* name
, const char* version
, Defined
,
1743 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1744 typename
elfcpp::Elf_types
<size
>::Elf_WXword ssize
,
1745 elfcpp::STT type
, elfcpp::STB binding
,
1746 elfcpp::STV visibility
, unsigned char nonvis
,
1747 bool offset_is_from_end
, bool only_if_ref
);
1749 // Define a symbol in an Output_segment, sized version.
1752 do_define_in_output_segment(
1753 const char* name
, const char* version
, Defined
, Output_segment
* os
,
1754 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1755 typename
elfcpp::Elf_types
<size
>::Elf_WXword ssize
,
1756 elfcpp::STT type
, elfcpp::STB binding
,
1757 elfcpp::STV visibility
, unsigned char nonvis
,
1758 Symbol::Segment_offset_base offset_base
, bool only_if_ref
);
1760 // Define a symbol as a constant, sized version.
1763 do_define_as_constant(
1764 const char* name
, const char* version
, Defined
,
1765 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1766 typename
elfcpp::Elf_types
<size
>::Elf_WXword ssize
,
1767 elfcpp::STT type
, elfcpp::STB binding
,
1768 elfcpp::STV visibility
, unsigned char nonvis
,
1769 bool only_if_ref
, bool force_override
);
1771 // Add any undefined symbols named on the command line to the symbol
1772 // table, sized version.
1775 do_add_undefined_symbols_from_command_line(Layout
*);
1777 // Add one undefined symbol.
1780 add_undefined_symbol_from_command_line(const char* name
);
1782 // Types of common symbols.
1784 enum Commons_section_type
1792 // Allocate the common symbols, sized version.
1795 do_allocate_commons(Layout
*, Mapfile
*, Sort_commons_order
);
1797 // Allocate the common symbols from one list.
1800 do_allocate_commons_list(Layout
*, Commons_section_type
, Commons_type
*,
1801 Mapfile
*, Sort_commons_order
);
1803 // Returns all of the lines attached to LOC, not just the one the
1804 // instruction actually came from. This helps the ODR checker avoid
1806 static std::vector
<std::string
>
1807 linenos_from_loc(const Task
* task
, const Symbol_location
& loc
);
1809 // Implement detect_odr_violations.
1810 template<int size
, bool big_endian
>
1812 sized_detect_odr_violations() const;
1814 // Finalize symbols specialized for size.
1817 sized_finalize(off_t
, Stringpool
*, unsigned int*);
1819 // Finalize a symbol. Return whether it should be added to the
1823 sized_finalize_symbol(Symbol
*);
1825 // Add a symbol the final symtab by setting its index.
1828 add_to_final_symtab(Symbol
*, Stringpool
*, unsigned int* pindex
, off_t
* poff
);
1830 // Write globals specialized for size and endianness.
1831 template<int size
, bool big_endian
>
1833 sized_write_globals(const Stringpool
*, const Stringpool
*,
1834 Output_symtab_xindex
*, Output_symtab_xindex
*,
1835 Output_file
*) const;
1837 // Write out a symbol to P.
1838 template<int size
, bool big_endian
>
1840 sized_write_symbol(Sized_symbol
<size
>*,
1841 typename
elfcpp::Elf_types
<size
>::Elf_Addr value
,
1842 unsigned int shndx
, elfcpp::STB
,
1843 const Stringpool
*, unsigned char* p
) const;
1845 // Possibly warn about an undefined symbol from a dynamic object.
1847 warn_about_undefined_dynobj_symbol(Symbol
*) const;
1849 // Write out a section symbol, specialized for size and endianness.
1850 template<int size
, bool big_endian
>
1852 sized_write_section_symbol(const Output_section
*, Output_symtab_xindex
*,
1853 Output_file
*, off_t
) const;
1855 // The type of the list of symbols which have been forced local.
1856 typedef std::vector
<Symbol
*> Forced_locals
;
1858 // A map from symbols with COPY relocs to the dynamic objects where
1859 // they are defined.
1860 typedef Unordered_map
<const Symbol
*, Dynobj
*> Copied_symbol_dynobjs
;
1862 // We increment this every time we see a new undefined symbol, for
1863 // use in archive groups.
1864 size_t saw_undefined_
;
1865 // The index of the first global symbol in the output file.
1866 unsigned int first_global_index_
;
1867 // The file offset within the output symtab section where we should
1870 // The number of global symbols we want to write out.
1871 unsigned int output_count_
;
1872 // The file offset of the global dynamic symbols, or 0 if none.
1873 off_t dynamic_offset_
;
1874 // The index of the first global dynamic symbol.
1875 unsigned int first_dynamic_global_index_
;
1876 // The number of global dynamic symbols, or 0 if none.
1877 unsigned int dynamic_count_
;
1878 // The symbol hash table.
1879 Symbol_table_type table_
;
1880 // A pool of symbol names. This is used for all global symbols.
1881 // Entries in the hash table point into this pool.
1882 Stringpool namepool_
;
1883 // Forwarding symbols.
1884 Unordered_map
<const Symbol
*, Symbol
*> forwarders_
;
1885 // Weak aliases. A symbol in this list points to the next alias.
1886 // The aliases point to each other in a circular list.
1887 Unordered_map
<Symbol
*, Symbol
*> weak_aliases_
;
1888 // We don't expect there to be very many common symbols, so we keep
1889 // a list of them. When we find a common symbol we add it to this
1890 // list. It is possible that by the time we process the list the
1891 // symbol is no longer a common symbol. It may also have become a
1893 Commons_type commons_
;
1894 // This is like the commons_ field, except that it holds TLS common
1896 Commons_type tls_commons_
;
1897 // This is for small common symbols.
1898 Commons_type small_commons_
;
1899 // This is for large common symbols.
1900 Commons_type large_commons_
;
1901 // A list of symbols which have been forced to be local. We don't
1902 // expect there to be very many of them, so we keep a list of them
1903 // rather than walking the whole table to find them.
1904 Forced_locals forced_locals_
;
1905 // Manage symbol warnings.
1907 // Manage potential One Definition Rule (ODR) violations.
1908 Odr_map candidate_odr_violations_
;
1910 // When we emit a COPY reloc for a symbol, we define it in an
1911 // Output_data. When it's time to emit version information for it,
1912 // we need to know the dynamic object in which we found the original
1913 // definition. This maps symbols with COPY relocs to the dynamic
1914 // object where they were defined.
1915 Copied_symbol_dynobjs copied_symbol_dynobjs_
;
1916 // Information parsed from the version script, if any.
1917 const Version_script_info
& version_script_
;
1918 Garbage_collection
* gc_
;
1922 // We inline get_sized_symbol for efficiency.
1926 Symbol_table::get_sized_symbol(Symbol
* sym
) const
1928 gold_assert(size
== parameters
->target().get_size());
1929 return static_cast<Sized_symbol
<size
>*>(sym
);
1933 const Sized_symbol
<size
>*
1934 Symbol_table::get_sized_symbol(const Symbol
* sym
) const
1936 gold_assert(size
== parameters
->target().get_size());
1937 return static_cast<const Sized_symbol
<size
>*>(sym
);
1940 } // End namespace gold.
1942 #endif // !defined(GOLD_SYMTAB_H)