* config/tc-avr.c (mcu_types): Add atmega16u4.
[binutils.git] / gold / symtab.h
blob043fb50f2288c3e2930f96f268a65f651f3915fd
1 // symtab.h -- the gold symbol table -*- C++ -*-
3 // Copyright 2006, 2007, 2008 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.
23 // Symbol_table
24 // The symbol table.
26 #include <string>
27 #include <utility>
28 #include <vector>
30 #include "elfcpp.h"
31 #include "parameters.h"
32 #include "stringpool.h"
33 #include "object.h"
35 #ifndef GOLD_SYMTAB_H
36 #define GOLD_SYMTAB_H
38 namespace gold
41 class Mapfile;
42 class Object;
43 class Relobj;
44 template<int size, bool big_endian>
45 class Sized_relobj;
46 class Dynobj;
47 template<int size, bool big_endian>
48 class Sized_dynobj;
49 class Versions;
50 class Version_script_info;
51 class Input_objects;
52 class Output_data;
53 class Output_section;
54 class Output_segment;
55 class Output_file;
56 class Output_symtab_xindex;
58 // The base class of an entry in the symbol table. The symbol table
59 // can have a lot of entries, so we don't want this class to big.
60 // Size dependent fields can be found in the template class
61 // Sized_symbol. Targets may support their own derived classes.
63 class Symbol
65 public:
66 // Because we want the class to be small, we don't use any virtual
67 // functions. But because symbols can be defined in different
68 // places, we need to classify them. This enum is the different
69 // sources of symbols we support.
70 enum Source
72 // Symbol defined in a relocatable or dynamic input file--this is
73 // the most common case.
74 FROM_OBJECT,
75 // Symbol defined in an Output_data, a special section created by
76 // the target.
77 IN_OUTPUT_DATA,
78 // Symbol defined in an Output_segment, with no associated
79 // section.
80 IN_OUTPUT_SEGMENT,
81 // Symbol value is constant.
82 IS_CONSTANT,
83 // Symbol is undefined.
84 IS_UNDEFINED
87 // When the source is IN_OUTPUT_SEGMENT, we need to describe what
88 // the offset means.
89 enum Segment_offset_base
91 // From the start of the segment.
92 SEGMENT_START,
93 // From the end of the segment.
94 SEGMENT_END,
95 // From the filesz of the segment--i.e., after the loaded bytes
96 // but before the bytes which are allocated but zeroed.
97 SEGMENT_BSS
100 // Return the symbol name.
101 const char*
102 name() const
103 { return this->name_; }
105 // Return the (ANSI) demangled version of the name, if
106 // parameters.demangle() is true. Otherwise, return the name. This
107 // is intended to be used only for logging errors, so it's not
108 // super-efficient.
109 std::string
110 demangled_name() const;
112 // Return the symbol version. This will return NULL for an
113 // unversioned symbol.
114 const char*
115 version() const
116 { return this->version_; }
118 // Return whether this version is the default for this symbol name
119 // (eg, "foo@@V2" is a default version; "foo@V1" is not). Only
120 // meaningful for versioned symbols.
121 bool
122 is_default() const
124 gold_assert(this->version_ != NULL);
125 return this->is_def_;
128 // Set that this version is the default for this symbol name.
129 void
130 set_is_default()
131 { this->is_def_ = true; }
133 // Return the symbol source.
134 Source
135 source() const
136 { return this->source_; }
138 // Return the object with which this symbol is associated.
139 Object*
140 object() const
142 gold_assert(this->source_ == FROM_OBJECT);
143 return this->u_.from_object.object;
146 // Return the index of the section in the input relocatable or
147 // dynamic object file.
148 unsigned int
149 shndx(bool* is_ordinary) const
151 gold_assert(this->source_ == FROM_OBJECT);
152 *is_ordinary = this->is_ordinary_shndx_;
153 return this->u_.from_object.shndx;
156 // Return the output data section with which this symbol is
157 // associated, if the symbol was specially defined with respect to
158 // an output data section.
159 Output_data*
160 output_data() const
162 gold_assert(this->source_ == IN_OUTPUT_DATA);
163 return this->u_.in_output_data.output_data;
166 // If this symbol was defined with respect to an output data
167 // section, return whether the value is an offset from end.
168 bool
169 offset_is_from_end() const
171 gold_assert(this->source_ == IN_OUTPUT_DATA);
172 return this->u_.in_output_data.offset_is_from_end;
175 // Return the output segment with which this symbol is associated,
176 // if the symbol was specially defined with respect to an output
177 // segment.
178 Output_segment*
179 output_segment() const
181 gold_assert(this->source_ == IN_OUTPUT_SEGMENT);
182 return this->u_.in_output_segment.output_segment;
185 // If this symbol was defined with respect to an output segment,
186 // return the offset base.
187 Segment_offset_base
188 offset_base() const
190 gold_assert(this->source_ == IN_OUTPUT_SEGMENT);
191 return this->u_.in_output_segment.offset_base;
194 // Return the symbol binding.
195 elfcpp::STB
196 binding() const
197 { return this->binding_; }
199 // Return the symbol type.
200 elfcpp::STT
201 type() const
202 { return this->type_; }
204 // Return the symbol visibility.
205 elfcpp::STV
206 visibility() const
207 { return this->visibility_; }
209 // Return the non-visibility part of the st_other field.
210 unsigned char
211 nonvis() const
212 { return this->nonvis_; }
214 // Return whether this symbol is a forwarder. This will never be
215 // true of a symbol found in the hash table, but may be true of
216 // symbol pointers attached to object files.
217 bool
218 is_forwarder() const
219 { return this->is_forwarder_; }
221 // Mark this symbol as a forwarder.
222 void
223 set_forwarder()
224 { this->is_forwarder_ = true; }
226 // Return whether this symbol has an alias in the weak aliases table
227 // in Symbol_table.
228 bool
229 has_alias() const
230 { return this->has_alias_; }
232 // Mark this symbol as having an alias.
233 void
234 set_has_alias()
235 { this->has_alias_ = true; }
237 // Return whether this symbol needs an entry in the dynamic symbol
238 // table.
239 bool
240 needs_dynsym_entry() const
242 return (this->needs_dynsym_entry_
243 || (this->in_reg() && this->in_dyn()));
246 // Mark this symbol as needing an entry in the dynamic symbol table.
247 void
248 set_needs_dynsym_entry()
249 { this->needs_dynsym_entry_ = true; }
251 // Return whether this symbol should be added to the dynamic symbol
252 // table.
253 bool
254 should_add_dynsym_entry() const;
256 // Return whether this symbol has been seen in a regular object.
257 bool
258 in_reg() const
259 { return this->in_reg_; }
261 // Mark this symbol as having been seen in a regular object.
262 void
263 set_in_reg()
264 { this->in_reg_ = true; }
266 // Return whether this symbol has been seen in a dynamic object.
267 bool
268 in_dyn() const
269 { return this->in_dyn_; }
271 // Mark this symbol as having been seen in a dynamic object.
272 void
273 set_in_dyn()
274 { this->in_dyn_ = true; }
276 // Return the index of this symbol in the output file symbol table.
277 // A value of -1U means that this symbol is not going into the
278 // output file. This starts out as zero, and is set to a non-zero
279 // value by Symbol_table::finalize. It is an error to ask for the
280 // symbol table index before it has been set.
281 unsigned int
282 symtab_index() const
284 gold_assert(this->symtab_index_ != 0);
285 return this->symtab_index_;
288 // Set the index of the symbol in the output file symbol table.
289 void
290 set_symtab_index(unsigned int index)
292 gold_assert(index != 0);
293 this->symtab_index_ = index;
296 // Return whether this symbol already has an index in the output
297 // file symbol table.
298 bool
299 has_symtab_index() const
300 { return this->symtab_index_ != 0; }
302 // Return the index of this symbol in the dynamic symbol table. A
303 // value of -1U means that this symbol is not going into the dynamic
304 // symbol table. This starts out as zero, and is set to a non-zero
305 // during Layout::finalize. It is an error to ask for the dynamic
306 // symbol table index before it has been set.
307 unsigned int
308 dynsym_index() const
310 gold_assert(this->dynsym_index_ != 0);
311 return this->dynsym_index_;
314 // Set the index of the symbol in the dynamic symbol table.
315 void
316 set_dynsym_index(unsigned int index)
318 gold_assert(index != 0);
319 this->dynsym_index_ = index;
322 // Return whether this symbol already has an index in the dynamic
323 // symbol table.
324 bool
325 has_dynsym_index() const
326 { return this->dynsym_index_ != 0; }
328 // Return whether this symbol has an entry in the GOT section.
329 // For a TLS symbol, this GOT entry will hold its tp-relative offset.
330 bool
331 has_got_offset(unsigned int got_type) const
332 { return this->got_offsets_.get_offset(got_type) != -1U; }
334 // Return the offset into the GOT section of this symbol.
335 unsigned int
336 got_offset(unsigned int got_type) const
338 unsigned int got_offset = this->got_offsets_.get_offset(got_type);
339 gold_assert(got_offset != -1U);
340 return got_offset;
343 // Set the GOT offset of this symbol.
344 void
345 set_got_offset(unsigned int got_type, unsigned int got_offset)
346 { this->got_offsets_.set_offset(got_type, got_offset); }
348 // Return whether this symbol has an entry in the PLT section.
349 bool
350 has_plt_offset() const
351 { return this->has_plt_offset_; }
353 // Return the offset into the PLT section of this symbol.
354 unsigned int
355 plt_offset() const
357 gold_assert(this->has_plt_offset());
358 return this->plt_offset_;
361 // Set the PLT offset of this symbol.
362 void
363 set_plt_offset(unsigned int plt_offset)
365 this->has_plt_offset_ = true;
366 this->plt_offset_ = plt_offset;
369 // Return whether this dynamic symbol needs a special value in the
370 // dynamic symbol table.
371 bool
372 needs_dynsym_value() const
373 { return this->needs_dynsym_value_; }
375 // Set that this dynamic symbol needs a special value in the dynamic
376 // symbol table.
377 void
378 set_needs_dynsym_value()
380 gold_assert(this->object()->is_dynamic());
381 this->needs_dynsym_value_ = true;
384 // Return true if the final value of this symbol is known at link
385 // time.
386 bool
387 final_value_is_known() const;
389 // Return whether this is a defined symbol (not undefined or
390 // common).
391 bool
392 is_defined() const
394 bool is_ordinary;
395 if (this->source_ != FROM_OBJECT)
396 return this->source_ != IS_UNDEFINED;
397 unsigned int shndx = this->shndx(&is_ordinary);
398 return (is_ordinary
399 ? shndx != elfcpp::SHN_UNDEF
400 : shndx != elfcpp::SHN_COMMON);
403 // Return true if this symbol is from a dynamic object.
404 bool
405 is_from_dynobj() const
407 return this->source_ == FROM_OBJECT && this->object()->is_dynamic();
410 // Return whether this is an undefined symbol.
411 bool
412 is_undefined() const
414 bool is_ordinary;
415 return ((this->source_ == FROM_OBJECT
416 && this->shndx(&is_ordinary) == elfcpp::SHN_UNDEF
417 && is_ordinary)
418 || this->source_ == IS_UNDEFINED);
421 // Return whether this is a weak undefined symbol.
422 bool
423 is_weak_undefined() const
424 { return this->is_undefined() && this->binding() == elfcpp::STB_WEAK; }
426 // Return whether this is an absolute symbol.
427 bool
428 is_absolute() const
430 bool is_ordinary;
431 return ((this->source_ == FROM_OBJECT
432 && this->shndx(&is_ordinary) == elfcpp::SHN_ABS
433 && !is_ordinary)
434 || this->source_ == IS_CONSTANT);
437 // Return whether this is a common symbol.
438 bool
439 is_common() const
441 bool is_ordinary;
442 return (this->source_ == FROM_OBJECT
443 && ((this->shndx(&is_ordinary) == elfcpp::SHN_COMMON
444 && !is_ordinary)
445 || this->type_ == elfcpp::STT_COMMON));
448 // Return whether this symbol can be seen outside this object.
449 bool
450 is_externally_visible() const
452 return (this->visibility_ == elfcpp::STV_DEFAULT
453 || this->visibility_ == elfcpp::STV_PROTECTED);
456 // Return true if this symbol can be preempted by a definition in
457 // another link unit.
458 bool
459 is_preemptible() const
461 // It doesn't make sense to ask whether a symbol defined in
462 // another object is preemptible.
463 gold_assert(!this->is_from_dynobj());
465 // It doesn't make sense to ask whether an undefined symbol
466 // is preemptible.
467 gold_assert(!this->is_undefined());
469 // If a symbol does not have default visibility, it can not be
470 // seen outside this link unit and therefore is not preemptible.
471 if (this->visibility_ != elfcpp::STV_DEFAULT)
472 return false;
474 // If this symbol has been forced to be a local symbol by a
475 // version script, then it is not visible outside this link unit
476 // and is not preemptible.
477 if (this->is_forced_local_)
478 return false;
480 // If we are not producing a shared library, then nothing is
481 // preemptible.
482 if (!parameters->options().shared())
483 return false;
485 // If the user used -Bsymbolic, then nothing is preemptible.
486 if (parameters->options().Bsymbolic())
487 return false;
489 // If the user used -Bsymbolic-functions, then functions are not
490 // preemptible. We explicitly check for not being STT_OBJECT,
491 // rather than for being STT_FUNC, because that is what the GNU
492 // linker does.
493 if (this->type() != elfcpp::STT_OBJECT
494 && parameters->options().Bsymbolic_functions())
495 return false;
497 // Otherwise the symbol is preemptible.
498 return true;
501 // Return true if this symbol is a function that needs a PLT entry.
502 // If the symbol is defined in a dynamic object or if it is subject
503 // to pre-emption, we need to make a PLT entry. If we're doing a
504 // static link, we don't create PLT entries.
505 bool
506 needs_plt_entry() const
508 return (!parameters->doing_static_link()
509 && this->type() == elfcpp::STT_FUNC
510 && (this->is_from_dynobj()
511 || this->is_undefined()
512 || this->is_preemptible()));
515 // When determining whether a reference to a symbol needs a dynamic
516 // relocation, we need to know several things about the reference.
517 // These flags may be or'ed together.
518 enum Reference_flags
520 // Reference to the symbol's absolute address.
521 ABSOLUTE_REF = 1,
522 // A non-PIC reference.
523 NON_PIC_REF = 2,
524 // A function call.
525 FUNCTION_CALL = 4
528 // Given a direct absolute or pc-relative static relocation against
529 // the global symbol, this function returns whether a dynamic relocation
530 // is needed.
532 bool
533 needs_dynamic_reloc(int flags) const
535 // No dynamic relocations in a static link!
536 if (parameters->doing_static_link())
537 return false;
539 // A reference to a weak undefined symbol from an executable should be
540 // statically resolved to 0, and does not need a dynamic relocation.
541 // This matches gnu ld behavior.
542 if (this->is_weak_undefined() && !parameters->options().shared())
543 return false;
545 // A reference to an absolute symbol does not need a dynamic relocation.
546 if (this->is_absolute())
547 return false;
549 // An absolute reference within a position-independent output file
550 // will need a dynamic relocation.
551 if ((flags & ABSOLUTE_REF)
552 && parameters->options().output_is_position_independent())
553 return true;
555 // A function call that can branch to a local PLT entry does not need
556 // a dynamic relocation. A non-pic pc-relative function call in a
557 // shared library cannot use a PLT entry.
558 if ((flags & FUNCTION_CALL)
559 && this->has_plt_offset()
560 && !((flags & NON_PIC_REF) && parameters->options().shared()))
561 return false;
563 // A reference to any PLT entry in a non-position-independent executable
564 // does not need a dynamic relocation.
565 if (!parameters->options().output_is_position_independent()
566 && this->has_plt_offset())
567 return false;
569 // A reference to a symbol defined in a dynamic object or to a
570 // symbol that is preemptible will need a dynamic relocation.
571 if (this->is_from_dynobj()
572 || this->is_undefined()
573 || this->is_preemptible())
574 return true;
576 // For all other cases, return FALSE.
577 return false;
580 // Whether we should use the PLT offset associated with a symbol for
581 // a relocation. IS_NON_PIC_REFERENCE is true if this is a non-PIC
582 // reloc--the same set of relocs for which we would pass NON_PIC_REF
583 // to the needs_dynamic_reloc function.
585 bool
586 use_plt_offset(bool is_non_pic_reference) const
588 // If the symbol doesn't have a PLT offset, then naturally we
589 // don't want to use it.
590 if (!this->has_plt_offset())
591 return false;
593 // If we are going to generate a dynamic relocation, then we will
594 // wind up using that, so no need to use the PLT entry.
595 if (this->needs_dynamic_reloc(FUNCTION_CALL
596 | (is_non_pic_reference
597 ? NON_PIC_REF
598 : 0)))
599 return false;
601 // If the symbol is from a dynamic object, we need to use the PLT
602 // entry.
603 if (this->is_from_dynobj())
604 return true;
606 // If we are generating a shared object, and this symbol is
607 // undefined or preemptible, we need to use the PLT entry.
608 if (parameters->options().shared()
609 && (this->is_undefined() || this->is_preemptible()))
610 return true;
612 // If this is a weak undefined symbol, we need to use the PLT
613 // entry; the symbol may be defined by a library loaded at
614 // runtime.
615 if (this->is_weak_undefined())
616 return true;
618 // Otherwise we can use the regular definition.
619 return false;
622 // Given a direct absolute static relocation against
623 // the global symbol, where a dynamic relocation is needed, this
624 // function returns whether a relative dynamic relocation can be used.
625 // The caller must determine separately whether the static relocation
626 // is compatible with a relative relocation.
628 bool
629 can_use_relative_reloc(bool is_function_call) const
631 // A function call that can branch to a local PLT entry can
632 // use a RELATIVE relocation.
633 if (is_function_call && this->has_plt_offset())
634 return true;
636 // A reference to a symbol defined in a dynamic object or to a
637 // symbol that is preemptible can not use a RELATIVE relocaiton.
638 if (this->is_from_dynobj()
639 || this->is_undefined()
640 || this->is_preemptible())
641 return false;
643 // For all other cases, return TRUE.
644 return true;
647 // Return the output section where this symbol is defined. Return
648 // NULL if the symbol has an absolute value.
649 Output_section*
650 output_section() const;
652 // Set the symbol's output section. This is used for symbols
653 // defined in scripts. This should only be called after the symbol
654 // table has been finalized.
655 void
656 set_output_section(Output_section*);
658 // Return whether there should be a warning for references to this
659 // symbol.
660 bool
661 has_warning() const
662 { return this->has_warning_; }
664 // Mark this symbol as having a warning.
665 void
666 set_has_warning()
667 { this->has_warning_ = true; }
669 // Return whether this symbol is defined by a COPY reloc from a
670 // dynamic object.
671 bool
672 is_copied_from_dynobj() const
673 { return this->is_copied_from_dynobj_; }
675 // Mark this symbol as defined by a COPY reloc.
676 void
677 set_is_copied_from_dynobj()
678 { this->is_copied_from_dynobj_ = true; }
680 // Return whether this symbol is forced to visibility STB_LOCAL
681 // by a "local:" entry in a version script.
682 bool
683 is_forced_local() const
684 { return this->is_forced_local_; }
686 // Mark this symbol as forced to STB_LOCAL visibility.
687 void
688 set_is_forced_local()
689 { this->is_forced_local_ = true; }
691 protected:
692 // Instances of this class should always be created at a specific
693 // size.
694 Symbol()
695 { memset(this, 0, sizeof *this); }
697 // Initialize the general fields.
698 void
699 init_fields(const char* name, const char* version,
700 elfcpp::STT type, elfcpp::STB binding,
701 elfcpp::STV visibility, unsigned char nonvis);
703 // Initialize fields from an ELF symbol in OBJECT. ST_SHNDX is the
704 // section index, IS_ORDINARY is whether it is a normal section
705 // index rather than a special code.
706 template<int size, bool big_endian>
707 void
708 init_base_object(const char *name, const char* version, Object* object,
709 const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
710 bool is_ordinary);
712 // Initialize fields for an Output_data.
713 void
714 init_base_output_data(const char* name, const char* version, Output_data*,
715 elfcpp::STT, elfcpp::STB, elfcpp::STV,
716 unsigned char nonvis, bool offset_is_from_end);
718 // Initialize fields for an Output_segment.
719 void
720 init_base_output_segment(const char* name, const char* version,
721 Output_segment* os, elfcpp::STT type,
722 elfcpp::STB binding, elfcpp::STV visibility,
723 unsigned char nonvis,
724 Segment_offset_base offset_base);
726 // Initialize fields for a constant.
727 void
728 init_base_constant(const char* name, const char* version, elfcpp::STT type,
729 elfcpp::STB binding, elfcpp::STV visibility,
730 unsigned char nonvis);
732 // Initialize fields for an undefined symbol.
733 void
734 init_base_undefined(const char* name, const char* version, elfcpp::STT type,
735 elfcpp::STB binding, elfcpp::STV visibility,
736 unsigned char nonvis);
738 // Override existing symbol.
739 template<int size, bool big_endian>
740 void
741 override_base(const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
742 bool is_ordinary, Object* object, const char* version);
744 // Override existing symbol with a special symbol.
745 void
746 override_base_with_special(const Symbol* from);
748 // Override symbol version.
749 void
750 override_version(const char* version);
752 // Allocate a common symbol by giving it a location in the output
753 // file.
754 void
755 allocate_base_common(Output_data*);
757 private:
758 Symbol(const Symbol&);
759 Symbol& operator=(const Symbol&);
761 // Symbol name (expected to point into a Stringpool).
762 const char* name_;
763 // Symbol version (expected to point into a Stringpool). This may
764 // be NULL.
765 const char* version_;
767 union
769 // This struct is used if SOURCE_ == FROM_OBJECT.
770 struct
772 // Object in which symbol is defined, or in which it was first
773 // seen.
774 Object* object;
775 // Section number in object_ in which symbol is defined.
776 unsigned int shndx;
777 } from_object;
779 // This struct is used if SOURCE_ == IN_OUTPUT_DATA.
780 struct
782 // Output_data in which symbol is defined. Before
783 // Layout::finalize the symbol's value is an offset within the
784 // Output_data.
785 Output_data* output_data;
786 // True if the offset is from the end, false if the offset is
787 // from the beginning.
788 bool offset_is_from_end;
789 } in_output_data;
791 // This struct is used if SOURCE_ == IN_OUTPUT_SEGMENT.
792 struct
794 // Output_segment in which the symbol is defined. Before
795 // Layout::finalize the symbol's value is an offset.
796 Output_segment* output_segment;
797 // The base to use for the offset before Layout::finalize.
798 Segment_offset_base offset_base;
799 } in_output_segment;
800 } u_;
802 // The index of this symbol in the output file. If the symbol is
803 // not going into the output file, this value is -1U. This field
804 // starts as always holding zero. It is set to a non-zero value by
805 // Symbol_table::finalize.
806 unsigned int symtab_index_;
808 // The index of this symbol in the dynamic symbol table. If the
809 // symbol is not going into the dynamic symbol table, this value is
810 // -1U. This field starts as always holding zero. It is set to a
811 // non-zero value during Layout::finalize.
812 unsigned int dynsym_index_;
814 // If this symbol has an entry in the GOT section (has_got_offset_
815 // is true), this holds the offset from the start of the GOT section.
816 // A symbol may have more than one GOT offset (e.g., when mixing
817 // modules compiled with two different TLS models), but will usually
818 // have at most one.
819 Got_offset_list got_offsets_;
821 // If this symbol has an entry in the PLT section (has_plt_offset_
822 // is true), then this is the offset from the start of the PLT
823 // section.
824 unsigned int plt_offset_;
826 // Symbol type (bits 0 to 3).
827 elfcpp::STT type_ : 4;
828 // Symbol binding (bits 4 to 7).
829 elfcpp::STB binding_ : 4;
830 // Symbol visibility (bits 8 to 9).
831 elfcpp::STV visibility_ : 2;
832 // Rest of symbol st_other field (bits 10 to 15).
833 unsigned int nonvis_ : 6;
834 // The type of symbol (bits 16 to 18).
835 Source source_ : 3;
836 // True if this symbol always requires special target-specific
837 // handling (bit 19).
838 bool is_target_special_ : 1;
839 // True if this is the default version of the symbol (bit 20).
840 bool is_def_ : 1;
841 // True if this symbol really forwards to another symbol. This is
842 // used when we discover after the fact that two different entries
843 // in the hash table really refer to the same symbol. This will
844 // never be set for a symbol found in the hash table, but may be set
845 // for a symbol found in the list of symbols attached to an Object.
846 // It forwards to the symbol found in the forwarders_ map of
847 // Symbol_table (bit 21).
848 bool is_forwarder_ : 1;
849 // True if the symbol has an alias in the weak_aliases table in
850 // Symbol_table (bit 22).
851 bool has_alias_ : 1;
852 // True if this symbol needs to be in the dynamic symbol table (bit
853 // 23).
854 bool needs_dynsym_entry_ : 1;
855 // True if we've seen this symbol in a regular object (bit 24).
856 bool in_reg_ : 1;
857 // True if we've seen this symbol in a dynamic object (bit 25).
858 bool in_dyn_ : 1;
859 // True if the symbol has an entry in the PLT section (bit 26).
860 bool has_plt_offset_ : 1;
861 // True if this is a dynamic symbol which needs a special value in
862 // the dynamic symbol table (bit 27).
863 bool needs_dynsym_value_ : 1;
864 // True if there is a warning for this symbol (bit 28).
865 bool has_warning_ : 1;
866 // True if we are using a COPY reloc for this symbol, so that the
867 // real definition lives in a dynamic object (bit 29).
868 bool is_copied_from_dynobj_ : 1;
869 // True if this symbol was forced to local visibility by a version
870 // script (bit 30).
871 bool is_forced_local_ : 1;
872 // True if the field u_.from_object.shndx is an ordinary section
873 // index, not one of the special codes from SHN_LORESERVE to
874 // SHN_HIRESERVE.
875 bool is_ordinary_shndx_ : 1;
878 // The parts of a symbol which are size specific. Using a template
879 // derived class like this helps us use less space on a 32-bit system.
881 template<int size>
882 class Sized_symbol : public Symbol
884 public:
885 typedef typename elfcpp::Elf_types<size>::Elf_Addr Value_type;
886 typedef typename elfcpp::Elf_types<size>::Elf_WXword Size_type;
888 Sized_symbol()
891 // Initialize fields from an ELF symbol in OBJECT. ST_SHNDX is the
892 // section index, IS_ORDINARY is whether it is a normal section
893 // index rather than a special code.
894 template<bool big_endian>
895 void
896 init_object(const char *name, const char* version, Object* object,
897 const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
898 bool is_ordinary);
900 // Initialize fields for an Output_data.
901 void
902 init_output_data(const char* name, const char* version, Output_data*,
903 Value_type value, Size_type symsize, elfcpp::STT,
904 elfcpp::STB, elfcpp::STV, unsigned char nonvis,
905 bool offset_is_from_end);
907 // Initialize fields for an Output_segment.
908 void
909 init_output_segment(const char* name, const char* version, Output_segment*,
910 Value_type value, Size_type symsize, elfcpp::STT,
911 elfcpp::STB, elfcpp::STV, unsigned char nonvis,
912 Segment_offset_base offset_base);
914 // Initialize fields for a constant.
915 void
916 init_constant(const char* name, const char* version, Value_type value,
917 Size_type symsize, elfcpp::STT, elfcpp::STB, elfcpp::STV,
918 unsigned char nonvis);
920 // Initialize fields for an undefined symbol.
921 void
922 init_undefined(const char* name, const char* version, elfcpp::STT,
923 elfcpp::STB, elfcpp::STV, unsigned char nonvis);
925 // Override existing symbol.
926 template<bool big_endian>
927 void
928 override(const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
929 bool is_ordinary, Object* object, const char* version);
931 // Override existing symbol with a special symbol.
932 void
933 override_with_special(const Sized_symbol<size>*);
935 // Return the symbol's value.
936 Value_type
937 value() const
938 { return this->value_; }
940 // Return the symbol's size (we can't call this 'size' because that
941 // is a template parameter).
942 Size_type
943 symsize() const
944 { return this->symsize_; }
946 // Set the symbol size. This is used when resolving common symbols.
947 void
948 set_symsize(Size_type symsize)
949 { this->symsize_ = symsize; }
951 // Set the symbol value. This is called when we store the final
952 // values of the symbols into the symbol table.
953 void
954 set_value(Value_type value)
955 { this->value_ = value; }
957 // Allocate a common symbol by giving it a location in the output
958 // file.
959 void
960 allocate_common(Output_data*, Value_type value);
962 private:
963 Sized_symbol(const Sized_symbol&);
964 Sized_symbol& operator=(const Sized_symbol&);
966 // Symbol value. Before Layout::finalize this is the offset in the
967 // input section. This is set to the final value during
968 // Layout::finalize.
969 Value_type value_;
970 // Symbol size.
971 Size_type symsize_;
974 // A struct describing a symbol defined by the linker, where the value
975 // of the symbol is defined based on an output section. This is used
976 // for symbols defined by the linker, like "_init_array_start".
978 struct Define_symbol_in_section
980 // The symbol name.
981 const char* name;
982 // The name of the output section with which this symbol should be
983 // associated. If there is no output section with that name, the
984 // symbol will be defined as zero.
985 const char* output_section;
986 // The offset of the symbol within the output section. This is an
987 // offset from the start of the output section, unless start_at_end
988 // is true, in which case this is an offset from the end of the
989 // output section.
990 uint64_t value;
991 // The size of the symbol.
992 uint64_t size;
993 // The symbol type.
994 elfcpp::STT type;
995 // The symbol binding.
996 elfcpp::STB binding;
997 // The symbol visibility.
998 elfcpp::STV visibility;
999 // The rest of the st_other field.
1000 unsigned char nonvis;
1001 // If true, the value field is an offset from the end of the output
1002 // section.
1003 bool offset_is_from_end;
1004 // If true, this symbol is defined only if we see a reference to it.
1005 bool only_if_ref;
1008 // A struct describing a symbol defined by the linker, where the value
1009 // of the symbol is defined based on a segment. This is used for
1010 // symbols defined by the linker, like "_end". We describe the
1011 // segment with which the symbol should be associated by its
1012 // characteristics. If no segment meets these characteristics, the
1013 // symbol will be defined as zero. If there is more than one segment
1014 // which meets these characteristics, we will use the first one.
1016 struct Define_symbol_in_segment
1018 // The symbol name.
1019 const char* name;
1020 // The segment type where the symbol should be defined, typically
1021 // PT_LOAD.
1022 elfcpp::PT segment_type;
1023 // Bitmask of segment flags which must be set.
1024 elfcpp::PF segment_flags_set;
1025 // Bitmask of segment flags which must be clear.
1026 elfcpp::PF segment_flags_clear;
1027 // The offset of the symbol within the segment. The offset is
1028 // calculated from the position set by offset_base.
1029 uint64_t value;
1030 // The size of the symbol.
1031 uint64_t size;
1032 // The symbol type.
1033 elfcpp::STT type;
1034 // The symbol binding.
1035 elfcpp::STB binding;
1036 // The symbol visibility.
1037 elfcpp::STV visibility;
1038 // The rest of the st_other field.
1039 unsigned char nonvis;
1040 // The base from which we compute the offset.
1041 Symbol::Segment_offset_base offset_base;
1042 // If true, this symbol is defined only if we see a reference to it.
1043 bool only_if_ref;
1046 // This class manages warnings. Warnings are a GNU extension. When
1047 // we see a section named .gnu.warning.SYM in an object file, and if
1048 // we wind using the definition of SYM from that object file, then we
1049 // will issue a warning for any relocation against SYM from a
1050 // different object file. The text of the warning is the contents of
1051 // the section. This is not precisely the definition used by the old
1052 // GNU linker; the old GNU linker treated an occurrence of
1053 // .gnu.warning.SYM as defining a warning symbol. A warning symbol
1054 // would trigger a warning on any reference. However, it was
1055 // inconsistent in that a warning in a dynamic object only triggered
1056 // if there was no definition in a regular object. This linker is
1057 // different in that we only issue a warning if we use the symbol
1058 // definition from the same object file as the warning section.
1060 class Warnings
1062 public:
1063 Warnings()
1064 : warnings_()
1067 // Add a warning for symbol NAME in object OBJ. WARNING is the text
1068 // of the warning.
1069 void
1070 add_warning(Symbol_table* symtab, const char* name, Object* obj,
1071 const std::string& warning);
1073 // For each symbol for which we should give a warning, make a note
1074 // on the symbol.
1075 void
1076 note_warnings(Symbol_table* symtab);
1078 // Issue a warning for a reference to SYM at RELINFO's location.
1079 template<int size, bool big_endian>
1080 void
1081 issue_warning(const Symbol* sym, const Relocate_info<size, big_endian>*,
1082 size_t relnum, off_t reloffset) const;
1084 private:
1085 Warnings(const Warnings&);
1086 Warnings& operator=(const Warnings&);
1088 // What we need to know to get the warning text.
1089 struct Warning_location
1091 // The object the warning is in.
1092 Object* object;
1093 // The warning text.
1094 std::string text;
1096 Warning_location()
1097 : object(NULL), text()
1100 void
1101 set(Object* o, const std::string& t)
1103 this->object = o;
1104 this->text = t;
1108 // A mapping from warning symbol names (canonicalized in
1109 // Symbol_table's namepool_ field) to warning information.
1110 typedef Unordered_map<const char*, Warning_location> Warning_table;
1112 Warning_table warnings_;
1115 // The main linker symbol table.
1117 class Symbol_table
1119 public:
1120 // COUNT is an estimate of how many symbosl will be inserted in the
1121 // symbol table. It's ok to put 0 if you don't know; a correct
1122 // guess will just save some CPU by reducing hashtable resizes.
1123 Symbol_table(unsigned int count, const Version_script_info& version_script);
1125 ~Symbol_table();
1127 // Add COUNT external symbols from the relocatable object RELOBJ to
1128 // the symbol table. SYMS is the symbols, SYMNDX_OFFSET is the
1129 // offset in the symbol table of the first symbol, SYM_NAMES is
1130 // their names, SYM_NAME_SIZE is the size of SYM_NAMES. This sets
1131 // SYMPOINTERS to point to the symbols in the symbol table. It sets
1132 // *DEFINED to the number of defined symbols.
1133 template<int size, bool big_endian>
1134 void
1135 add_from_relobj(Sized_relobj<size, big_endian>* relobj,
1136 const unsigned char* syms, size_t count,
1137 size_t symndx_offset, const char* sym_names,
1138 size_t sym_name_size,
1139 typename Sized_relobj<size, big_endian>::Symbols*,
1140 size_t* defined);
1142 // Add COUNT dynamic symbols from the dynamic object DYNOBJ to the
1143 // symbol table. SYMS is the symbols. SYM_NAMES is their names.
1144 // SYM_NAME_SIZE is the size of SYM_NAMES. The other parameters are
1145 // symbol version data.
1146 template<int size, bool big_endian>
1147 void
1148 add_from_dynobj(Sized_dynobj<size, big_endian>* dynobj,
1149 const unsigned char* syms, size_t count,
1150 const char* sym_names, size_t sym_name_size,
1151 const unsigned char* versym, size_t versym_size,
1152 const std::vector<const char*>*,
1153 typename Sized_relobj<size, big_endian>::Symbols*,
1154 size_t* defined);
1156 // Define a special symbol based on an Output_data. It is a
1157 // multiple definition error if this symbol is already defined.
1158 Symbol*
1159 define_in_output_data(const char* name, const char* version,
1160 Output_data*, uint64_t value, uint64_t symsize,
1161 elfcpp::STT type, elfcpp::STB binding,
1162 elfcpp::STV visibility, unsigned char nonvis,
1163 bool offset_is_from_end, bool only_if_ref);
1165 // Define a special symbol based on an Output_segment. It is a
1166 // multiple definition error if this symbol is already defined.
1167 Symbol*
1168 define_in_output_segment(const char* name, const char* version,
1169 Output_segment*, uint64_t value, uint64_t symsize,
1170 elfcpp::STT type, elfcpp::STB binding,
1171 elfcpp::STV visibility, unsigned char nonvis,
1172 Symbol::Segment_offset_base, bool only_if_ref);
1174 // Define a special symbol with a constant value. It is a multiple
1175 // definition error if this symbol is already defined.
1176 Symbol*
1177 define_as_constant(const char* name, const char* version,
1178 uint64_t value, uint64_t symsize, elfcpp::STT type,
1179 elfcpp::STB binding, elfcpp::STV visibility,
1180 unsigned char nonvis, bool only_if_ref,
1181 bool force_override);
1183 // Define a set of symbols in output sections. If ONLY_IF_REF is
1184 // true, only define them if they are referenced.
1185 void
1186 define_symbols(const Layout*, int count, const Define_symbol_in_section*,
1187 bool only_if_ref);
1189 // Define a set of symbols in output segments. If ONLY_IF_REF is
1190 // true, only defined them if they are referenced.
1191 void
1192 define_symbols(const Layout*, int count, const Define_symbol_in_segment*,
1193 bool only_if_ref);
1195 // Define SYM using a COPY reloc. POSD is the Output_data where the
1196 // symbol should be defined--typically a .dyn.bss section. VALUE is
1197 // the offset within POSD.
1198 template<int size>
1199 void
1200 define_with_copy_reloc(Sized_symbol<size>* sym, Output_data* posd,
1201 typename elfcpp::Elf_types<size>::Elf_Addr);
1203 // Look up a symbol.
1204 Symbol*
1205 lookup(const char*, const char* version = NULL) const;
1207 // Return the real symbol associated with the forwarder symbol FROM.
1208 Symbol*
1209 resolve_forwards(const Symbol* from) const;
1211 // Return the sized version of a symbol in this table.
1212 template<int size>
1213 Sized_symbol<size>*
1214 get_sized_symbol(Symbol*) const;
1216 template<int size>
1217 const Sized_symbol<size>*
1218 get_sized_symbol(const Symbol*) const;
1220 // Return the count of undefined symbols seen.
1222 saw_undefined() const
1223 { return this->saw_undefined_; }
1225 // Allocate the common symbols
1226 void
1227 allocate_commons(Layout*, Mapfile*);
1229 // Add a warning for symbol NAME in object OBJ. WARNING is the text
1230 // of the warning.
1231 void
1232 add_warning(const char* name, Object* obj, const std::string& warning)
1233 { this->warnings_.add_warning(this, name, obj, warning); }
1235 // Canonicalize a symbol name for use in the hash table.
1236 const char*
1237 canonicalize_name(const char* name)
1238 { return this->namepool_.add(name, true, NULL); }
1240 // Possibly issue a warning for a reference to SYM at LOCATION which
1241 // is in OBJ.
1242 template<int size, bool big_endian>
1243 void
1244 issue_warning(const Symbol* sym,
1245 const Relocate_info<size, big_endian>* relinfo,
1246 size_t relnum, off_t reloffset) const
1247 { this->warnings_.issue_warning(sym, relinfo, relnum, reloffset); }
1249 // Check candidate_odr_violations_ to find symbols with the same name
1250 // but apparently different definitions (different source-file/line-no).
1251 void
1252 detect_odr_violations(const Task*, const char* output_file_name) const;
1254 // Add any undefined symbols named on the command line to the symbol
1255 // table.
1256 void
1257 add_undefined_symbols_from_command_line();
1259 // SYM is defined using a COPY reloc. Return the dynamic object
1260 // where the original definition was found.
1261 Dynobj*
1262 get_copy_source(const Symbol* sym) const;
1264 // Set the dynamic symbol indexes. INDEX is the index of the first
1265 // global dynamic symbol. Pointers to the symbols are stored into
1266 // the vector. The names are stored into the Stringpool. This
1267 // returns an updated dynamic symbol index.
1268 unsigned int
1269 set_dynsym_indexes(unsigned int index, std::vector<Symbol*>*,
1270 Stringpool*, Versions*);
1272 // Finalize the symbol table after we have set the final addresses
1273 // of all the input sections. This sets the final symbol indexes,
1274 // values and adds the names to *POOL. *PLOCAL_SYMCOUNT is the
1275 // index of the first global symbol. OFF is the file offset of the
1276 // global symbol table, DYNOFF is the offset of the globals in the
1277 // dynamic symbol table, DYN_GLOBAL_INDEX is the index of the first
1278 // global dynamic symbol, and DYNCOUNT is the number of global
1279 // dynamic symbols. This records the parameters, and returns the
1280 // new file offset. It updates *PLOCAL_SYMCOUNT if it created any
1281 // local symbols.
1282 off_t
1283 finalize(off_t off, off_t dynoff, size_t dyn_global_index, size_t dyncount,
1284 Stringpool* pool, unsigned int *plocal_symcount);
1286 // Write out the global symbols.
1287 void
1288 write_globals(const Input_objects*, const Stringpool*, const Stringpool*,
1289 Output_symtab_xindex*, Output_symtab_xindex*,
1290 Output_file*) const;
1292 // Write out a section symbol. Return the updated offset.
1293 void
1294 write_section_symbol(const Output_section*, Output_symtab_xindex*,
1295 Output_file*, off_t) const;
1297 // Dump statistical information to stderr.
1298 void
1299 print_stats() const;
1301 // Return the version script information.
1302 const Version_script_info&
1303 version_script() const
1304 { return version_script_; }
1306 private:
1307 Symbol_table(const Symbol_table&);
1308 Symbol_table& operator=(const Symbol_table&);
1310 // The type of the list of common symbols.
1311 typedef std::vector<Symbol*> Commons_type;
1313 // Make FROM a forwarder symbol to TO.
1314 void
1315 make_forwarder(Symbol* from, Symbol* to);
1317 // Add a symbol.
1318 template<int size, bool big_endian>
1319 Sized_symbol<size>*
1320 add_from_object(Object*, const char *name, Stringpool::Key name_key,
1321 const char *version, Stringpool::Key version_key,
1322 bool def, const elfcpp::Sym<size, big_endian>& sym,
1323 unsigned int st_shndx, bool is_ordinary,
1324 unsigned int orig_st_shndx);
1326 // Resolve symbols.
1327 template<int size, bool big_endian>
1328 void
1329 resolve(Sized_symbol<size>* to,
1330 const elfcpp::Sym<size, big_endian>& sym,
1331 unsigned int st_shndx, bool is_ordinary,
1332 unsigned int orig_st_shndx,
1333 Object*, const char* version);
1335 template<int size, bool big_endian>
1336 void
1337 resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from);
1339 // Record that a symbol is forced to be local by a version script.
1340 void
1341 force_local(Symbol*);
1343 // Adjust NAME and *NAME_KEY for wrapping.
1344 const char*
1345 wrap_symbol(Object* object, const char*, Stringpool::Key* name_key);
1347 // Whether we should override a symbol, based on flags in
1348 // resolve.cc.
1349 static bool
1350 should_override(const Symbol*, unsigned int, Object*, bool*);
1352 // Override a symbol.
1353 template<int size, bool big_endian>
1354 void
1355 override(Sized_symbol<size>* tosym,
1356 const elfcpp::Sym<size, big_endian>& fromsym,
1357 unsigned int st_shndx, bool is_ordinary,
1358 Object* object, const char* version);
1360 // Whether we should override a symbol with a special symbol which
1361 // is automatically defined by the linker.
1362 static bool
1363 should_override_with_special(const Symbol*);
1365 // Override a symbol with a special symbol.
1366 template<int size>
1367 void
1368 override_with_special(Sized_symbol<size>* tosym,
1369 const Sized_symbol<size>* fromsym);
1371 // Record all weak alias sets for a dynamic object.
1372 template<int size>
1373 void
1374 record_weak_aliases(std::vector<Sized_symbol<size>*>*);
1376 // Define a special symbol.
1377 template<int size, bool big_endian>
1378 Sized_symbol<size>*
1379 define_special_symbol(const char** pname, const char** pversion,
1380 bool only_if_ref, Sized_symbol<size>** poldsym);
1382 // Define a symbol in an Output_data, sized version.
1383 template<int size>
1384 Sized_symbol<size>*
1385 do_define_in_output_data(const char* name, const char* version, Output_data*,
1386 typename elfcpp::Elf_types<size>::Elf_Addr value,
1387 typename elfcpp::Elf_types<size>::Elf_WXword ssize,
1388 elfcpp::STT type, elfcpp::STB binding,
1389 elfcpp::STV visibility, unsigned char nonvis,
1390 bool offset_is_from_end, bool only_if_ref);
1392 // Define a symbol in an Output_segment, sized version.
1393 template<int size>
1394 Sized_symbol<size>*
1395 do_define_in_output_segment(
1396 const char* name, const char* version, Output_segment* os,
1397 typename elfcpp::Elf_types<size>::Elf_Addr value,
1398 typename elfcpp::Elf_types<size>::Elf_WXword ssize,
1399 elfcpp::STT type, elfcpp::STB binding,
1400 elfcpp::STV visibility, unsigned char nonvis,
1401 Symbol::Segment_offset_base offset_base, bool only_if_ref);
1403 // Define a symbol as a constant, sized version.
1404 template<int size>
1405 Sized_symbol<size>*
1406 do_define_as_constant(
1407 const char* name, const char* version,
1408 typename elfcpp::Elf_types<size>::Elf_Addr value,
1409 typename elfcpp::Elf_types<size>::Elf_WXword ssize,
1410 elfcpp::STT type, elfcpp::STB binding,
1411 elfcpp::STV visibility, unsigned char nonvis,
1412 bool only_if_ref, bool force_override);
1414 // Add any undefined symbols named on the command line to the symbol
1415 // table, sized version.
1416 template<int size>
1417 void
1418 do_add_undefined_symbols_from_command_line();
1420 // Allocate the common symbols, sized version.
1421 template<int size>
1422 void
1423 do_allocate_commons(Layout*, Mapfile*);
1425 // Allocate the common symbols from one list.
1426 template<int size>
1427 void
1428 do_allocate_commons_list(Layout*, bool is_tls, Commons_type*, Mapfile*);
1430 // Implement detect_odr_violations.
1431 template<int size, bool big_endian>
1432 void
1433 sized_detect_odr_violations() const;
1435 // Finalize symbols specialized for size.
1436 template<int size>
1437 off_t
1438 sized_finalize(off_t, Stringpool*, unsigned int*);
1440 // Finalize a symbol. Return whether it should be added to the
1441 // symbol table.
1442 template<int size>
1443 bool
1444 sized_finalize_symbol(Symbol*);
1446 // Add a symbol the final symtab by setting its index.
1447 template<int size>
1448 void
1449 add_to_final_symtab(Symbol*, Stringpool*, unsigned int* pindex, off_t* poff);
1451 // Write globals specialized for size and endianness.
1452 template<int size, bool big_endian>
1453 void
1454 sized_write_globals(const Input_objects*, const Stringpool*,
1455 const Stringpool*, Output_symtab_xindex*,
1456 Output_symtab_xindex*, Output_file*) const;
1458 // Write out a symbol to P.
1459 template<int size, bool big_endian>
1460 void
1461 sized_write_symbol(Sized_symbol<size>*,
1462 typename elfcpp::Elf_types<size>::Elf_Addr value,
1463 unsigned int shndx,
1464 const Stringpool*, unsigned char* p) const;
1466 // Possibly warn about an undefined symbol from a dynamic object.
1467 void
1468 warn_about_undefined_dynobj_symbol(const Input_objects*, Symbol*) const;
1470 // Write out a section symbol, specialized for size and endianness.
1471 template<int size, bool big_endian>
1472 void
1473 sized_write_section_symbol(const Output_section*, Output_symtab_xindex*,
1474 Output_file*, off_t) const;
1476 // The type of the symbol hash table.
1478 typedef std::pair<Stringpool::Key, Stringpool::Key> Symbol_table_key;
1480 struct Symbol_table_hash
1482 size_t
1483 operator()(const Symbol_table_key&) const;
1486 struct Symbol_table_eq
1488 bool
1489 operator()(const Symbol_table_key&, const Symbol_table_key&) const;
1492 typedef Unordered_map<Symbol_table_key, Symbol*, Symbol_table_hash,
1493 Symbol_table_eq> Symbol_table_type;
1495 // The type of the list of symbols which have been forced local.
1496 typedef std::vector<Symbol*> Forced_locals;
1498 // A map from symbols with COPY relocs to the dynamic objects where
1499 // they are defined.
1500 typedef Unordered_map<const Symbol*, Dynobj*> Copied_symbol_dynobjs;
1502 // A map from symbol name (as a pointer into the namepool) to all
1503 // the locations the symbols is (weakly) defined (and certain other
1504 // conditions are met). This map will be used later to detect
1505 // possible One Definition Rule (ODR) violations.
1506 struct Symbol_location
1508 Object* object; // Object where the symbol is defined.
1509 unsigned int shndx; // Section-in-object where the symbol is defined.
1510 off_t offset; // Offset-in-section where the symbol is defined.
1511 bool operator==(const Symbol_location& that) const
1513 return (this->object == that.object
1514 && this->shndx == that.shndx
1515 && this->offset == that.offset);
1519 struct Symbol_location_hash
1521 size_t operator()(const Symbol_location& loc) const
1522 { return reinterpret_cast<uintptr_t>(loc.object) ^ loc.offset ^ loc.shndx; }
1525 typedef Unordered_map<const char*,
1526 Unordered_set<Symbol_location, Symbol_location_hash> >
1527 Odr_map;
1529 // We increment this every time we see a new undefined symbol, for
1530 // use in archive groups.
1531 int saw_undefined_;
1532 // The index of the first global symbol in the output file.
1533 unsigned int first_global_index_;
1534 // The file offset within the output symtab section where we should
1535 // write the table.
1536 off_t offset_;
1537 // The number of global symbols we want to write out.
1538 unsigned int output_count_;
1539 // The file offset of the global dynamic symbols, or 0 if none.
1540 off_t dynamic_offset_;
1541 // The index of the first global dynamic symbol.
1542 unsigned int first_dynamic_global_index_;
1543 // The number of global dynamic symbols, or 0 if none.
1544 unsigned int dynamic_count_;
1545 // The symbol hash table.
1546 Symbol_table_type table_;
1547 // A pool of symbol names. This is used for all global symbols.
1548 // Entries in the hash table point into this pool.
1549 Stringpool namepool_;
1550 // Forwarding symbols.
1551 Unordered_map<const Symbol*, Symbol*> forwarders_;
1552 // Weak aliases. A symbol in this list points to the next alias.
1553 // The aliases point to each other in a circular list.
1554 Unordered_map<Symbol*, Symbol*> weak_aliases_;
1555 // We don't expect there to be very many common symbols, so we keep
1556 // a list of them. When we find a common symbol we add it to this
1557 // list. It is possible that by the time we process the list the
1558 // symbol is no longer a common symbol. It may also have become a
1559 // forwarder.
1560 Commons_type commons_;
1561 // This is like the commons_ field, except that it holds TLS common
1562 // symbols.
1563 Commons_type tls_commons_;
1564 // A list of symbols which have been forced to be local. We don't
1565 // expect there to be very many of them, so we keep a list of them
1566 // rather than walking the whole table to find them.
1567 Forced_locals forced_locals_;
1568 // Manage symbol warnings.
1569 Warnings warnings_;
1570 // Manage potential One Definition Rule (ODR) violations.
1571 Odr_map candidate_odr_violations_;
1573 // When we emit a COPY reloc for a symbol, we define it in an
1574 // Output_data. When it's time to emit version information for it,
1575 // we need to know the dynamic object in which we found the original
1576 // definition. This maps symbols with COPY relocs to the dynamic
1577 // object where they were defined.
1578 Copied_symbol_dynobjs copied_symbol_dynobjs_;
1579 // Information parsed from the version script, if any.
1580 const Version_script_info& version_script_;
1583 // We inline get_sized_symbol for efficiency.
1585 template<int size>
1586 Sized_symbol<size>*
1587 Symbol_table::get_sized_symbol(Symbol* sym) const
1589 gold_assert(size == parameters->target().get_size());
1590 return static_cast<Sized_symbol<size>*>(sym);
1593 template<int size>
1594 const Sized_symbol<size>*
1595 Symbol_table::get_sized_symbol(const Symbol* sym) const
1597 gold_assert(size == parameters->target().get_size());
1598 return static_cast<const Sized_symbol<size>*>(sym);
1601 } // End namespace gold.
1603 #endif // !defined(GOLD_SYMTAB_H)