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[binutils.git] / gold / symtab.h
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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 template<int size, bool big_endian>
47 class Sized_pluginobj;
48 class Dynobj;
49 template<int size, bool big_endian>
50 class Sized_dynobj;
51 class Versions;
52 class Version_script_info;
53 class Input_objects;
54 class Output_data;
55 class Output_section;
56 class Output_segment;
57 class Output_file;
58 class Output_symtab_xindex;
60 // The base class of an entry in the symbol table. The symbol table
61 // can have a lot of entries, so we don't want this class to big.
62 // Size dependent fields can be found in the template class
63 // Sized_symbol. Targets may support their own derived classes.
65 class Symbol
67 public:
68 // Because we want the class to be small, we don't use any virtual
69 // functions. But because symbols can be defined in different
70 // places, we need to classify them. This enum is the different
71 // sources of symbols we support.
72 enum Source
74 // Symbol defined in a relocatable or dynamic input file--this is
75 // the most common case.
76 FROM_OBJECT,
77 // Symbol defined in an Output_data, a special section created by
78 // the target.
79 IN_OUTPUT_DATA,
80 // Symbol defined in an Output_segment, with no associated
81 // section.
82 IN_OUTPUT_SEGMENT,
83 // Symbol value is constant.
84 IS_CONSTANT,
85 // Symbol is undefined.
86 IS_UNDEFINED
89 // When the source is IN_OUTPUT_SEGMENT, we need to describe what
90 // the offset means.
91 enum Segment_offset_base
93 // From the start of the segment.
94 SEGMENT_START,
95 // From the end of the segment.
96 SEGMENT_END,
97 // From the filesz of the segment--i.e., after the loaded bytes
98 // but before the bytes which are allocated but zeroed.
99 SEGMENT_BSS
102 // Return the symbol name.
103 const char*
104 name() const
105 { return this->name_; }
107 // Return the (ANSI) demangled version of the name, if
108 // parameters.demangle() is true. Otherwise, return the name. This
109 // is intended to be used only for logging errors, so it's not
110 // super-efficient.
111 std::string
112 demangled_name() const;
114 // Return the symbol version. This will return NULL for an
115 // unversioned symbol.
116 const char*
117 version() const
118 { return this->version_; }
120 // Return whether this version is the default for this symbol name
121 // (eg, "foo@@V2" is a default version; "foo@V1" is not). Only
122 // meaningful for versioned symbols.
123 bool
124 is_default() const
126 gold_assert(this->version_ != NULL);
127 return this->is_def_;
130 // Set that this version is the default for this symbol name.
131 void
132 set_is_default()
133 { this->is_def_ = true; }
135 // Return the symbol source.
136 Source
137 source() const
138 { return this->source_; }
140 // Return the object with which this symbol is associated.
141 Object*
142 object() const
144 gold_assert(this->source_ == FROM_OBJECT);
145 return this->u_.from_object.object;
148 // Return the index of the section in the input relocatable or
149 // dynamic object file.
150 unsigned int
151 shndx(bool* is_ordinary) const
153 gold_assert(this->source_ == FROM_OBJECT);
154 *is_ordinary = this->is_ordinary_shndx_;
155 return this->u_.from_object.shndx;
158 // Return the output data section with which this symbol is
159 // associated, if the symbol was specially defined with respect to
160 // an output data section.
161 Output_data*
162 output_data() const
164 gold_assert(this->source_ == IN_OUTPUT_DATA);
165 return this->u_.in_output_data.output_data;
168 // If this symbol was defined with respect to an output data
169 // section, return whether the value is an offset from end.
170 bool
171 offset_is_from_end() const
173 gold_assert(this->source_ == IN_OUTPUT_DATA);
174 return this->u_.in_output_data.offset_is_from_end;
177 // Return the output segment with which this symbol is associated,
178 // if the symbol was specially defined with respect to an output
179 // segment.
180 Output_segment*
181 output_segment() const
183 gold_assert(this->source_ == IN_OUTPUT_SEGMENT);
184 return this->u_.in_output_segment.output_segment;
187 // If this symbol was defined with respect to an output segment,
188 // return the offset base.
189 Segment_offset_base
190 offset_base() const
192 gold_assert(this->source_ == IN_OUTPUT_SEGMENT);
193 return this->u_.in_output_segment.offset_base;
196 // Return the symbol binding.
197 elfcpp::STB
198 binding() const
199 { return this->binding_; }
201 // Return the symbol type.
202 elfcpp::STT
203 type() const
204 { return this->type_; }
206 // Return the symbol visibility.
207 elfcpp::STV
208 visibility() const
209 { return this->visibility_; }
211 // Return the non-visibility part of the st_other field.
212 unsigned char
213 nonvis() const
214 { return this->nonvis_; }
216 // Return whether this symbol is a forwarder. This will never be
217 // true of a symbol found in the hash table, but may be true of
218 // symbol pointers attached to object files.
219 bool
220 is_forwarder() const
221 { return this->is_forwarder_; }
223 // Mark this symbol as a forwarder.
224 void
225 set_forwarder()
226 { this->is_forwarder_ = true; }
228 // Return whether this symbol has an alias in the weak aliases table
229 // in Symbol_table.
230 bool
231 has_alias() const
232 { return this->has_alias_; }
234 // Mark this symbol as having an alias.
235 void
236 set_has_alias()
237 { this->has_alias_ = true; }
239 // Return whether this symbol needs an entry in the dynamic symbol
240 // table.
241 bool
242 needs_dynsym_entry() const
244 return (this->needs_dynsym_entry_
245 || (this->in_reg() && this->in_dyn()));
248 // Mark this symbol as needing an entry in the dynamic symbol table.
249 void
250 set_needs_dynsym_entry()
251 { this->needs_dynsym_entry_ = true; }
253 // Return whether this symbol should be added to the dynamic symbol
254 // table.
255 bool
256 should_add_dynsym_entry() const;
258 // Return whether this symbol has been seen in a regular object.
259 bool
260 in_reg() const
261 { return this->in_reg_; }
263 // Mark this symbol as having been seen in a regular object.
264 void
265 set_in_reg()
266 { this->in_reg_ = true; }
268 // Return whether this symbol has been seen in a dynamic object.
269 bool
270 in_dyn() const
271 { return this->in_dyn_; }
273 // Mark this symbol as having been seen in a dynamic object.
274 void
275 set_in_dyn()
276 { this->in_dyn_ = true; }
278 // Return whether this symbol has been seen in a real ELF object.
279 // (IN_REG will return TRUE if the symbol has been seen in either
280 // a real ELF object or an object claimed by a plugin.)
281 bool
282 in_real_elf() const
283 { return this->in_real_elf_; }
285 // Mark this symbol as having been seen in a real ELF object.
286 void
287 set_in_real_elf()
288 { this->in_real_elf_ = true; }
290 // Return the index of this symbol in the output file symbol table.
291 // A value of -1U means that this symbol is not going into the
292 // output file. This starts out as zero, and is set to a non-zero
293 // value by Symbol_table::finalize. It is an error to ask for the
294 // symbol table index before it has been set.
295 unsigned int
296 symtab_index() const
298 gold_assert(this->symtab_index_ != 0);
299 return this->symtab_index_;
302 // Set the index of the symbol in the output file symbol table.
303 void
304 set_symtab_index(unsigned int index)
306 gold_assert(index != 0);
307 this->symtab_index_ = index;
310 // Return whether this symbol already has an index in the output
311 // file symbol table.
312 bool
313 has_symtab_index() const
314 { return this->symtab_index_ != 0; }
316 // Return the index of this symbol in the dynamic symbol table. A
317 // value of -1U means that this symbol is not going into the dynamic
318 // symbol table. This starts out as zero, and is set to a non-zero
319 // during Layout::finalize. It is an error to ask for the dynamic
320 // symbol table index before it has been set.
321 unsigned int
322 dynsym_index() const
324 gold_assert(this->dynsym_index_ != 0);
325 return this->dynsym_index_;
328 // Set the index of the symbol in the dynamic symbol table.
329 void
330 set_dynsym_index(unsigned int index)
332 gold_assert(index != 0);
333 this->dynsym_index_ = index;
336 // Return whether this symbol already has an index in the dynamic
337 // symbol table.
338 bool
339 has_dynsym_index() const
340 { return this->dynsym_index_ != 0; }
342 // Return whether this symbol has an entry in the GOT section.
343 // For a TLS symbol, this GOT entry will hold its tp-relative offset.
344 bool
345 has_got_offset(unsigned int got_type) const
346 { return this->got_offsets_.get_offset(got_type) != -1U; }
348 // Return the offset into the GOT section of this symbol.
349 unsigned int
350 got_offset(unsigned int got_type) const
352 unsigned int got_offset = this->got_offsets_.get_offset(got_type);
353 gold_assert(got_offset != -1U);
354 return got_offset;
357 // Set the GOT offset of this symbol.
358 void
359 set_got_offset(unsigned int got_type, unsigned int got_offset)
360 { this->got_offsets_.set_offset(got_type, got_offset); }
362 // Return whether this symbol has an entry in the PLT section.
363 bool
364 has_plt_offset() const
365 { return this->has_plt_offset_; }
367 // Return the offset into the PLT section of this symbol.
368 unsigned int
369 plt_offset() const
371 gold_assert(this->has_plt_offset());
372 return this->plt_offset_;
375 // Set the PLT offset of this symbol.
376 void
377 set_plt_offset(unsigned int plt_offset)
379 this->has_plt_offset_ = true;
380 this->plt_offset_ = plt_offset;
383 // Return whether this dynamic symbol needs a special value in the
384 // dynamic symbol table.
385 bool
386 needs_dynsym_value() const
387 { return this->needs_dynsym_value_; }
389 // Set that this dynamic symbol needs a special value in the dynamic
390 // symbol table.
391 void
392 set_needs_dynsym_value()
394 gold_assert(this->object()->is_dynamic());
395 this->needs_dynsym_value_ = true;
398 // Return true if the final value of this symbol is known at link
399 // time.
400 bool
401 final_value_is_known() const;
403 // Return whether this is a defined symbol (not undefined or
404 // common).
405 bool
406 is_defined() const
408 bool is_ordinary;
409 if (this->source_ != FROM_OBJECT)
410 return this->source_ != IS_UNDEFINED;
411 unsigned int shndx = this->shndx(&is_ordinary);
412 return (is_ordinary
413 ? shndx != elfcpp::SHN_UNDEF
414 : shndx != elfcpp::SHN_COMMON);
417 // Return true if this symbol is from a dynamic object.
418 bool
419 is_from_dynobj() const
421 return this->source_ == FROM_OBJECT && this->object()->is_dynamic();
424 // Return whether this is an undefined symbol.
425 bool
426 is_undefined() const
428 bool is_ordinary;
429 return ((this->source_ == FROM_OBJECT
430 && this->shndx(&is_ordinary) == elfcpp::SHN_UNDEF
431 && is_ordinary)
432 || this->source_ == IS_UNDEFINED);
435 // Return whether this is a weak undefined symbol.
436 bool
437 is_weak_undefined() const
438 { return this->is_undefined() && this->binding() == elfcpp::STB_WEAK; }
440 // Return whether this is an absolute symbol.
441 bool
442 is_absolute() const
444 bool is_ordinary;
445 return ((this->source_ == FROM_OBJECT
446 && this->shndx(&is_ordinary) == elfcpp::SHN_ABS
447 && !is_ordinary)
448 || this->source_ == IS_CONSTANT);
451 // Return whether this is a common symbol.
452 bool
453 is_common() const
455 bool is_ordinary;
456 return (this->source_ == FROM_OBJECT
457 && ((this->shndx(&is_ordinary) == elfcpp::SHN_COMMON
458 && !is_ordinary)
459 || this->type_ == elfcpp::STT_COMMON));
462 // Return whether this symbol can be seen outside this object.
463 bool
464 is_externally_visible() const
466 return (this->visibility_ == elfcpp::STV_DEFAULT
467 || this->visibility_ == elfcpp::STV_PROTECTED);
470 // Return true if this symbol can be preempted by a definition in
471 // another link unit.
472 bool
473 is_preemptible() const
475 // It doesn't make sense to ask whether a symbol defined in
476 // another object is preemptible.
477 gold_assert(!this->is_from_dynobj());
479 // It doesn't make sense to ask whether an undefined symbol
480 // is preemptible.
481 gold_assert(!this->is_undefined());
483 // If a symbol does not have default visibility, it can not be
484 // seen outside this link unit and therefore is not preemptible.
485 if (this->visibility_ != elfcpp::STV_DEFAULT)
486 return false;
488 // If this symbol has been forced to be a local symbol by a
489 // version script, then it is not visible outside this link unit
490 // and is not preemptible.
491 if (this->is_forced_local_)
492 return false;
494 // If we are not producing a shared library, then nothing is
495 // preemptible.
496 if (!parameters->options().shared())
497 return false;
499 // If the user used -Bsymbolic, then nothing is preemptible.
500 if (parameters->options().Bsymbolic())
501 return false;
503 // If the user used -Bsymbolic-functions, then functions are not
504 // preemptible. We explicitly check for not being STT_OBJECT,
505 // rather than for being STT_FUNC, because that is what the GNU
506 // linker does.
507 if (this->type() != elfcpp::STT_OBJECT
508 && parameters->options().Bsymbolic_functions())
509 return false;
511 // Otherwise the symbol is preemptible.
512 return true;
515 // Return true if this symbol is a function that needs a PLT entry.
516 // If the symbol is defined in a dynamic object or if it is subject
517 // to pre-emption, we need to make a PLT entry. If we're doing a
518 // static link, we don't create PLT entries.
519 bool
520 needs_plt_entry() const
522 return (!parameters->doing_static_link()
523 && this->type() == elfcpp::STT_FUNC
524 && (this->is_from_dynobj()
525 || this->is_undefined()
526 || this->is_preemptible()));
529 // When determining whether a reference to a symbol needs a dynamic
530 // relocation, we need to know several things about the reference.
531 // These flags may be or'ed together.
532 enum Reference_flags
534 // Reference to the symbol's absolute address.
535 ABSOLUTE_REF = 1,
536 // A non-PIC reference.
537 NON_PIC_REF = 2,
538 // A function call.
539 FUNCTION_CALL = 4
542 // Given a direct absolute or pc-relative static relocation against
543 // the global symbol, this function returns whether a dynamic relocation
544 // is needed.
546 bool
547 needs_dynamic_reloc(int flags) const
549 // No dynamic relocations in a static link!
550 if (parameters->doing_static_link())
551 return false;
553 // A reference to a weak undefined symbol from an executable should be
554 // statically resolved to 0, and does not need a dynamic relocation.
555 // This matches gnu ld behavior.
556 if (this->is_weak_undefined() && !parameters->options().shared())
557 return false;
559 // A reference to an absolute symbol does not need a dynamic relocation.
560 if (this->is_absolute())
561 return false;
563 // An absolute reference within a position-independent output file
564 // will need a dynamic relocation.
565 if ((flags & ABSOLUTE_REF)
566 && parameters->options().output_is_position_independent())
567 return true;
569 // A function call that can branch to a local PLT entry does not need
570 // a dynamic relocation. A non-pic pc-relative function call in a
571 // shared library cannot use a PLT entry.
572 if ((flags & FUNCTION_CALL)
573 && this->has_plt_offset()
574 && !((flags & NON_PIC_REF) && parameters->options().shared()))
575 return false;
577 // A reference to any PLT entry in a non-position-independent executable
578 // does not need a dynamic relocation.
579 if (!parameters->options().output_is_position_independent()
580 && this->has_plt_offset())
581 return false;
583 // A reference to a symbol defined in a dynamic object or to a
584 // symbol that is preemptible will need a dynamic relocation.
585 if (this->is_from_dynobj()
586 || this->is_undefined()
587 || this->is_preemptible())
588 return true;
590 // For all other cases, return FALSE.
591 return false;
594 // Whether we should use the PLT offset associated with a symbol for
595 // a relocation. IS_NON_PIC_REFERENCE is true if this is a non-PIC
596 // reloc--the same set of relocs for which we would pass NON_PIC_REF
597 // to the needs_dynamic_reloc function.
599 bool
600 use_plt_offset(bool is_non_pic_reference) const
602 // If the symbol doesn't have a PLT offset, then naturally we
603 // don't want to use it.
604 if (!this->has_plt_offset())
605 return false;
607 // If we are going to generate a dynamic relocation, then we will
608 // wind up using that, so no need to use the PLT entry.
609 if (this->needs_dynamic_reloc(FUNCTION_CALL
610 | (is_non_pic_reference
611 ? NON_PIC_REF
612 : 0)))
613 return false;
615 // If the symbol is from a dynamic object, we need to use the PLT
616 // entry.
617 if (this->is_from_dynobj())
618 return true;
620 // If we are generating a shared object, and this symbol is
621 // undefined or preemptible, we need to use the PLT entry.
622 if (parameters->options().shared()
623 && (this->is_undefined() || this->is_preemptible()))
624 return true;
626 // If this is a weak undefined symbol, we need to use the PLT
627 // entry; the symbol may be defined by a library loaded at
628 // runtime.
629 if (this->is_weak_undefined())
630 return true;
632 // Otherwise we can use the regular definition.
633 return false;
636 // Given a direct absolute static relocation against
637 // the global symbol, where a dynamic relocation is needed, this
638 // function returns whether a relative dynamic relocation can be used.
639 // The caller must determine separately whether the static relocation
640 // is compatible with a relative relocation.
642 bool
643 can_use_relative_reloc(bool is_function_call) const
645 // A function call that can branch to a local PLT entry can
646 // use a RELATIVE relocation.
647 if (is_function_call && this->has_plt_offset())
648 return true;
650 // A reference to a symbol defined in a dynamic object or to a
651 // symbol that is preemptible can not use a RELATIVE relocaiton.
652 if (this->is_from_dynobj()
653 || this->is_undefined()
654 || this->is_preemptible())
655 return false;
657 // For all other cases, return TRUE.
658 return true;
661 // Return the output section where this symbol is defined. Return
662 // NULL if the symbol has an absolute value.
663 Output_section*
664 output_section() const;
666 // Set the symbol's output section. This is used for symbols
667 // defined in scripts. This should only be called after the symbol
668 // table has been finalized.
669 void
670 set_output_section(Output_section*);
672 // Return whether there should be a warning for references to this
673 // symbol.
674 bool
675 has_warning() const
676 { return this->has_warning_; }
678 // Mark this symbol as having a warning.
679 void
680 set_has_warning()
681 { this->has_warning_ = true; }
683 // Return whether this symbol is defined by a COPY reloc from a
684 // dynamic object.
685 bool
686 is_copied_from_dynobj() const
687 { return this->is_copied_from_dynobj_; }
689 // Mark this symbol as defined by a COPY reloc.
690 void
691 set_is_copied_from_dynobj()
692 { this->is_copied_from_dynobj_ = true; }
694 // Return whether this symbol is forced to visibility STB_LOCAL
695 // by a "local:" entry in a version script.
696 bool
697 is_forced_local() const
698 { return this->is_forced_local_; }
700 // Mark this symbol as forced to STB_LOCAL visibility.
701 void
702 set_is_forced_local()
703 { this->is_forced_local_ = true; }
705 protected:
706 // Instances of this class should always be created at a specific
707 // size.
708 Symbol()
709 { memset(this, 0, sizeof *this); }
711 // Initialize the general fields.
712 void
713 init_fields(const char* name, const char* version,
714 elfcpp::STT type, elfcpp::STB binding,
715 elfcpp::STV visibility, unsigned char nonvis);
717 // Initialize fields from an ELF symbol in OBJECT. ST_SHNDX is the
718 // section index, IS_ORDINARY is whether it is a normal section
719 // index rather than a special code.
720 template<int size, bool big_endian>
721 void
722 init_base_object(const char *name, const char* version, Object* object,
723 const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
724 bool is_ordinary);
726 // Initialize fields for an Output_data.
727 void
728 init_base_output_data(const char* name, const char* version, Output_data*,
729 elfcpp::STT, elfcpp::STB, elfcpp::STV,
730 unsigned char nonvis, bool offset_is_from_end);
732 // Initialize fields for an Output_segment.
733 void
734 init_base_output_segment(const char* name, const char* version,
735 Output_segment* os, elfcpp::STT type,
736 elfcpp::STB binding, elfcpp::STV visibility,
737 unsigned char nonvis,
738 Segment_offset_base offset_base);
740 // Initialize fields for a constant.
741 void
742 init_base_constant(const char* name, const char* version, elfcpp::STT type,
743 elfcpp::STB binding, elfcpp::STV visibility,
744 unsigned char nonvis);
746 // Initialize fields for an undefined symbol.
747 void
748 init_base_undefined(const char* name, const char* version, elfcpp::STT type,
749 elfcpp::STB binding, elfcpp::STV visibility,
750 unsigned char nonvis);
752 // Override existing symbol.
753 template<int size, bool big_endian>
754 void
755 override_base(const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
756 bool is_ordinary, Object* object, const char* version);
758 // Override existing symbol with a special symbol.
759 void
760 override_base_with_special(const Symbol* from);
762 // Override symbol version.
763 void
764 override_version(const char* version);
766 // Allocate a common symbol by giving it a location in the output
767 // file.
768 void
769 allocate_base_common(Output_data*);
771 private:
772 Symbol(const Symbol&);
773 Symbol& operator=(const Symbol&);
775 // Symbol name (expected to point into a Stringpool).
776 const char* name_;
777 // Symbol version (expected to point into a Stringpool). This may
778 // be NULL.
779 const char* version_;
781 union
783 // This struct is used if SOURCE_ == FROM_OBJECT.
784 struct
786 // Object in which symbol is defined, or in which it was first
787 // seen.
788 Object* object;
789 // Section number in object_ in which symbol is defined.
790 unsigned int shndx;
791 } from_object;
793 // This struct is used if SOURCE_ == IN_OUTPUT_DATA.
794 struct
796 // Output_data in which symbol is defined. Before
797 // Layout::finalize the symbol's value is an offset within the
798 // Output_data.
799 Output_data* output_data;
800 // True if the offset is from the end, false if the offset is
801 // from the beginning.
802 bool offset_is_from_end;
803 } in_output_data;
805 // This struct is used if SOURCE_ == IN_OUTPUT_SEGMENT.
806 struct
808 // Output_segment in which the symbol is defined. Before
809 // Layout::finalize the symbol's value is an offset.
810 Output_segment* output_segment;
811 // The base to use for the offset before Layout::finalize.
812 Segment_offset_base offset_base;
813 } in_output_segment;
814 } u_;
816 // The index of this symbol in the output file. If the symbol is
817 // not going into the output file, this value is -1U. This field
818 // starts as always holding zero. It is set to a non-zero value by
819 // Symbol_table::finalize.
820 unsigned int symtab_index_;
822 // The index of this symbol in the dynamic symbol table. If the
823 // symbol is not going into the dynamic symbol table, this value is
824 // -1U. This field starts as always holding zero. It is set to a
825 // non-zero value during Layout::finalize.
826 unsigned int dynsym_index_;
828 // If this symbol has an entry in the GOT section (has_got_offset_
829 // is true), this holds the offset from the start of the GOT section.
830 // A symbol may have more than one GOT offset (e.g., when mixing
831 // modules compiled with two different TLS models), but will usually
832 // have at most one.
833 Got_offset_list got_offsets_;
835 // If this symbol has an entry in the PLT section (has_plt_offset_
836 // is true), then this is the offset from the start of the PLT
837 // section.
838 unsigned int plt_offset_;
840 // Symbol type (bits 0 to 3).
841 elfcpp::STT type_ : 4;
842 // Symbol binding (bits 4 to 7).
843 elfcpp::STB binding_ : 4;
844 // Symbol visibility (bits 8 to 9).
845 elfcpp::STV visibility_ : 2;
846 // Rest of symbol st_other field (bits 10 to 15).
847 unsigned int nonvis_ : 6;
848 // The type of symbol (bits 16 to 18).
849 Source source_ : 3;
850 // True if this symbol always requires special target-specific
851 // handling (bit 19).
852 bool is_target_special_ : 1;
853 // True if this is the default version of the symbol (bit 20).
854 bool is_def_ : 1;
855 // True if this symbol really forwards to another symbol. This is
856 // used when we discover after the fact that two different entries
857 // in the hash table really refer to the same symbol. This will
858 // never be set for a symbol found in the hash table, but may be set
859 // for a symbol found in the list of symbols attached to an Object.
860 // It forwards to the symbol found in the forwarders_ map of
861 // Symbol_table (bit 21).
862 bool is_forwarder_ : 1;
863 // True if the symbol has an alias in the weak_aliases table in
864 // Symbol_table (bit 22).
865 bool has_alias_ : 1;
866 // True if this symbol needs to be in the dynamic symbol table (bit
867 // 23).
868 bool needs_dynsym_entry_ : 1;
869 // True if we've seen this symbol in a regular object (bit 24).
870 bool in_reg_ : 1;
871 // True if we've seen this symbol in a dynamic object (bit 25).
872 bool in_dyn_ : 1;
873 // True if the symbol has an entry in the PLT section (bit 26).
874 bool has_plt_offset_ : 1;
875 // True if this is a dynamic symbol which needs a special value in
876 // the dynamic symbol table (bit 27).
877 bool needs_dynsym_value_ : 1;
878 // True if there is a warning for this symbol (bit 28).
879 bool has_warning_ : 1;
880 // True if we are using a COPY reloc for this symbol, so that the
881 // real definition lives in a dynamic object (bit 29).
882 bool is_copied_from_dynobj_ : 1;
883 // True if this symbol was forced to local visibility by a version
884 // script (bit 30).
885 bool is_forced_local_ : 1;
886 // True if the field u_.from_object.shndx is an ordinary section
887 // index, not one of the special codes from SHN_LORESERVE to
888 // SHN_HIRESERVE (bit 31).
889 bool is_ordinary_shndx_ : 1;
890 // True if we've seen this symbol in a real ELF object.
891 bool in_real_elf_ : 1;
894 // The parts of a symbol which are size specific. Using a template
895 // derived class like this helps us use less space on a 32-bit system.
897 template<int size>
898 class Sized_symbol : public Symbol
900 public:
901 typedef typename elfcpp::Elf_types<size>::Elf_Addr Value_type;
902 typedef typename elfcpp::Elf_types<size>::Elf_WXword Size_type;
904 Sized_symbol()
907 // Initialize fields from an ELF symbol in OBJECT. ST_SHNDX is the
908 // section index, IS_ORDINARY is whether it is a normal section
909 // index rather than a special code.
910 template<bool big_endian>
911 void
912 init_object(const char *name, const char* version, Object* object,
913 const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
914 bool is_ordinary);
916 // Initialize fields for an Output_data.
917 void
918 init_output_data(const char* name, const char* version, Output_data*,
919 Value_type value, Size_type symsize, elfcpp::STT,
920 elfcpp::STB, elfcpp::STV, unsigned char nonvis,
921 bool offset_is_from_end);
923 // Initialize fields for an Output_segment.
924 void
925 init_output_segment(const char* name, const char* version, Output_segment*,
926 Value_type value, Size_type symsize, elfcpp::STT,
927 elfcpp::STB, elfcpp::STV, unsigned char nonvis,
928 Segment_offset_base offset_base);
930 // Initialize fields for a constant.
931 void
932 init_constant(const char* name, const char* version, Value_type value,
933 Size_type symsize, elfcpp::STT, elfcpp::STB, elfcpp::STV,
934 unsigned char nonvis);
936 // Initialize fields for an undefined symbol.
937 void
938 init_undefined(const char* name, const char* version, elfcpp::STT,
939 elfcpp::STB, elfcpp::STV, unsigned char nonvis);
941 // Override existing symbol.
942 template<bool big_endian>
943 void
944 override(const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
945 bool is_ordinary, Object* object, const char* version);
947 // Override existing symbol with a special symbol.
948 void
949 override_with_special(const Sized_symbol<size>*);
951 // Return the symbol's value.
952 Value_type
953 value() const
954 { return this->value_; }
956 // Return the symbol's size (we can't call this 'size' because that
957 // is a template parameter).
958 Size_type
959 symsize() const
960 { return this->symsize_; }
962 // Set the symbol size. This is used when resolving common symbols.
963 void
964 set_symsize(Size_type symsize)
965 { this->symsize_ = symsize; }
967 // Set the symbol value. This is called when we store the final
968 // values of the symbols into the symbol table.
969 void
970 set_value(Value_type value)
971 { this->value_ = value; }
973 // Allocate a common symbol by giving it a location in the output
974 // file.
975 void
976 allocate_common(Output_data*, Value_type value);
978 private:
979 Sized_symbol(const Sized_symbol&);
980 Sized_symbol& operator=(const Sized_symbol&);
982 // Symbol value. Before Layout::finalize this is the offset in the
983 // input section. This is set to the final value during
984 // Layout::finalize.
985 Value_type value_;
986 // Symbol size.
987 Size_type symsize_;
990 // A struct describing a symbol defined by the linker, where the value
991 // of the symbol is defined based on an output section. This is used
992 // for symbols defined by the linker, like "_init_array_start".
994 struct Define_symbol_in_section
996 // The symbol name.
997 const char* name;
998 // The name of the output section with which this symbol should be
999 // associated. If there is no output section with that name, the
1000 // symbol will be defined as zero.
1001 const char* output_section;
1002 // The offset of the symbol within the output section. This is an
1003 // offset from the start of the output section, unless start_at_end
1004 // is true, in which case this is an offset from the end of the
1005 // output section.
1006 uint64_t value;
1007 // The size of the symbol.
1008 uint64_t size;
1009 // The symbol type.
1010 elfcpp::STT type;
1011 // The symbol binding.
1012 elfcpp::STB binding;
1013 // The symbol visibility.
1014 elfcpp::STV visibility;
1015 // The rest of the st_other field.
1016 unsigned char nonvis;
1017 // If true, the value field is an offset from the end of the output
1018 // section.
1019 bool offset_is_from_end;
1020 // If true, this symbol is defined only if we see a reference to it.
1021 bool only_if_ref;
1024 // A struct describing a symbol defined by the linker, where the value
1025 // of the symbol is defined based on a segment. This is used for
1026 // symbols defined by the linker, like "_end". We describe the
1027 // segment with which the symbol should be associated by its
1028 // characteristics. If no segment meets these characteristics, the
1029 // symbol will be defined as zero. If there is more than one segment
1030 // which meets these characteristics, we will use the first one.
1032 struct Define_symbol_in_segment
1034 // The symbol name.
1035 const char* name;
1036 // The segment type where the symbol should be defined, typically
1037 // PT_LOAD.
1038 elfcpp::PT segment_type;
1039 // Bitmask of segment flags which must be set.
1040 elfcpp::PF segment_flags_set;
1041 // Bitmask of segment flags which must be clear.
1042 elfcpp::PF segment_flags_clear;
1043 // The offset of the symbol within the segment. The offset is
1044 // calculated from the position set by offset_base.
1045 uint64_t value;
1046 // The size of the symbol.
1047 uint64_t size;
1048 // The symbol type.
1049 elfcpp::STT type;
1050 // The symbol binding.
1051 elfcpp::STB binding;
1052 // The symbol visibility.
1053 elfcpp::STV visibility;
1054 // The rest of the st_other field.
1055 unsigned char nonvis;
1056 // The base from which we compute the offset.
1057 Symbol::Segment_offset_base offset_base;
1058 // If true, this symbol is defined only if we see a reference to it.
1059 bool only_if_ref;
1062 // This class manages warnings. Warnings are a GNU extension. When
1063 // we see a section named .gnu.warning.SYM in an object file, and if
1064 // we wind using the definition of SYM from that object file, then we
1065 // will issue a warning for any relocation against SYM from a
1066 // different object file. The text of the warning is the contents of
1067 // the section. This is not precisely the definition used by the old
1068 // GNU linker; the old GNU linker treated an occurrence of
1069 // .gnu.warning.SYM as defining a warning symbol. A warning symbol
1070 // would trigger a warning on any reference. However, it was
1071 // inconsistent in that a warning in a dynamic object only triggered
1072 // if there was no definition in a regular object. This linker is
1073 // different in that we only issue a warning if we use the symbol
1074 // definition from the same object file as the warning section.
1076 class Warnings
1078 public:
1079 Warnings()
1080 : warnings_()
1083 // Add a warning for symbol NAME in object OBJ. WARNING is the text
1084 // of the warning.
1085 void
1086 add_warning(Symbol_table* symtab, const char* name, Object* obj,
1087 const std::string& warning);
1089 // For each symbol for which we should give a warning, make a note
1090 // on the symbol.
1091 void
1092 note_warnings(Symbol_table* symtab);
1094 // Issue a warning for a reference to SYM at RELINFO's location.
1095 template<int size, bool big_endian>
1096 void
1097 issue_warning(const Symbol* sym, const Relocate_info<size, big_endian>*,
1098 size_t relnum, off_t reloffset) const;
1100 private:
1101 Warnings(const Warnings&);
1102 Warnings& operator=(const Warnings&);
1104 // What we need to know to get the warning text.
1105 struct Warning_location
1107 // The object the warning is in.
1108 Object* object;
1109 // The warning text.
1110 std::string text;
1112 Warning_location()
1113 : object(NULL), text()
1116 void
1117 set(Object* o, const std::string& t)
1119 this->object = o;
1120 this->text = t;
1124 // A mapping from warning symbol names (canonicalized in
1125 // Symbol_table's namepool_ field) to warning information.
1126 typedef Unordered_map<const char*, Warning_location> Warning_table;
1128 Warning_table warnings_;
1131 // The main linker symbol table.
1133 class Symbol_table
1135 public:
1136 // COUNT is an estimate of how many symbosl will be inserted in the
1137 // symbol table. It's ok to put 0 if you don't know; a correct
1138 // guess will just save some CPU by reducing hashtable resizes.
1139 Symbol_table(unsigned int count, const Version_script_info& version_script);
1141 ~Symbol_table();
1143 // Add COUNT external symbols from the relocatable object RELOBJ to
1144 // the symbol table. SYMS is the symbols, SYMNDX_OFFSET is the
1145 // offset in the symbol table of the first symbol, SYM_NAMES is
1146 // their names, SYM_NAME_SIZE is the size of SYM_NAMES. This sets
1147 // SYMPOINTERS to point to the symbols in the symbol table. It sets
1148 // *DEFINED to the number of defined symbols.
1149 template<int size, bool big_endian>
1150 void
1151 add_from_relobj(Sized_relobj<size, big_endian>* relobj,
1152 const unsigned char* syms, size_t count,
1153 size_t symndx_offset, const char* sym_names,
1154 size_t sym_name_size,
1155 typename Sized_relobj<size, big_endian>::Symbols*,
1156 size_t* defined);
1158 // Add one external symbol from the plugin object OBJ to the symbol table.
1159 // Returns a pointer to the resolved symbol in the symbol table.
1160 template<int size, bool big_endian>
1161 Symbol*
1162 add_from_pluginobj(Sized_pluginobj<size, big_endian>* obj,
1163 const char* name, const char* ver,
1164 elfcpp::Sym<size, big_endian>* sym);
1166 // Add COUNT dynamic symbols from the dynamic object DYNOBJ to the
1167 // symbol table. SYMS is the symbols. SYM_NAMES is their names.
1168 // SYM_NAME_SIZE is the size of SYM_NAMES. The other parameters are
1169 // symbol version data.
1170 template<int size, bool big_endian>
1171 void
1172 add_from_dynobj(Sized_dynobj<size, big_endian>* dynobj,
1173 const unsigned char* syms, size_t count,
1174 const char* sym_names, size_t sym_name_size,
1175 const unsigned char* versym, size_t versym_size,
1176 const std::vector<const char*>*,
1177 typename Sized_relobj<size, big_endian>::Symbols*,
1178 size_t* defined);
1180 // Define a special symbol based on an Output_data. It is a
1181 // multiple definition error if this symbol is already defined.
1182 Symbol*
1183 define_in_output_data(const char* name, const char* version,
1184 Output_data*, uint64_t value, uint64_t symsize,
1185 elfcpp::STT type, elfcpp::STB binding,
1186 elfcpp::STV visibility, unsigned char nonvis,
1187 bool offset_is_from_end, bool only_if_ref);
1189 // Define a special symbol based on an Output_segment. It is a
1190 // multiple definition error if this symbol is already defined.
1191 Symbol*
1192 define_in_output_segment(const char* name, const char* version,
1193 Output_segment*, uint64_t value, uint64_t symsize,
1194 elfcpp::STT type, elfcpp::STB binding,
1195 elfcpp::STV visibility, unsigned char nonvis,
1196 Symbol::Segment_offset_base, bool only_if_ref);
1198 // Define a special symbol with a constant value. It is a multiple
1199 // definition error if this symbol is already defined.
1200 Symbol*
1201 define_as_constant(const char* name, const char* version,
1202 uint64_t value, uint64_t symsize, elfcpp::STT type,
1203 elfcpp::STB binding, elfcpp::STV visibility,
1204 unsigned char nonvis, bool only_if_ref,
1205 bool force_override);
1207 // Define a set of symbols in output sections. If ONLY_IF_REF is
1208 // true, only define them if they are referenced.
1209 void
1210 define_symbols(const Layout*, int count, const Define_symbol_in_section*,
1211 bool only_if_ref);
1213 // Define a set of symbols in output segments. If ONLY_IF_REF is
1214 // true, only defined them if they are referenced.
1215 void
1216 define_symbols(const Layout*, int count, const Define_symbol_in_segment*,
1217 bool only_if_ref);
1219 // Define SYM using a COPY reloc. POSD is the Output_data where the
1220 // symbol should be defined--typically a .dyn.bss section. VALUE is
1221 // the offset within POSD.
1222 template<int size>
1223 void
1224 define_with_copy_reloc(Sized_symbol<size>* sym, Output_data* posd,
1225 typename elfcpp::Elf_types<size>::Elf_Addr);
1227 // Look up a symbol.
1228 Symbol*
1229 lookup(const char*, const char* version = NULL) const;
1231 // Return the real symbol associated with the forwarder symbol FROM.
1232 Symbol*
1233 resolve_forwards(const Symbol* from) const;
1235 // Return the sized version of a symbol in this table.
1236 template<int size>
1237 Sized_symbol<size>*
1238 get_sized_symbol(Symbol*) const;
1240 template<int size>
1241 const Sized_symbol<size>*
1242 get_sized_symbol(const Symbol*) const;
1244 // Return the count of undefined symbols seen.
1246 saw_undefined() const
1247 { return this->saw_undefined_; }
1249 // Allocate the common symbols
1250 void
1251 allocate_commons(Layout*, Mapfile*);
1253 // Add a warning for symbol NAME in object OBJ. WARNING is the text
1254 // of the warning.
1255 void
1256 add_warning(const char* name, Object* obj, const std::string& warning)
1257 { this->warnings_.add_warning(this, name, obj, warning); }
1259 // Canonicalize a symbol name for use in the hash table.
1260 const char*
1261 canonicalize_name(const char* name)
1262 { return this->namepool_.add(name, true, NULL); }
1264 // Possibly issue a warning for a reference to SYM at LOCATION which
1265 // is in OBJ.
1266 template<int size, bool big_endian>
1267 void
1268 issue_warning(const Symbol* sym,
1269 const Relocate_info<size, big_endian>* relinfo,
1270 size_t relnum, off_t reloffset) const
1271 { this->warnings_.issue_warning(sym, relinfo, relnum, reloffset); }
1273 // Check candidate_odr_violations_ to find symbols with the same name
1274 // but apparently different definitions (different source-file/line-no).
1275 void
1276 detect_odr_violations(const Task*, const char* output_file_name) const;
1278 // Add any undefined symbols named on the command line to the symbol
1279 // table.
1280 void
1281 add_undefined_symbols_from_command_line();
1283 // SYM is defined using a COPY reloc. Return the dynamic object
1284 // where the original definition was found.
1285 Dynobj*
1286 get_copy_source(const Symbol* sym) const;
1288 // Set the dynamic symbol indexes. INDEX is the index of the first
1289 // global dynamic symbol. Pointers to the symbols are stored into
1290 // the vector. The names are stored into the Stringpool. This
1291 // returns an updated dynamic symbol index.
1292 unsigned int
1293 set_dynsym_indexes(unsigned int index, std::vector<Symbol*>*,
1294 Stringpool*, Versions*);
1296 // Finalize the symbol table after we have set the final addresses
1297 // of all the input sections. This sets the final symbol indexes,
1298 // values and adds the names to *POOL. *PLOCAL_SYMCOUNT is the
1299 // index of the first global symbol. OFF is the file offset of the
1300 // global symbol table, DYNOFF is the offset of the globals in the
1301 // dynamic symbol table, DYN_GLOBAL_INDEX is the index of the first
1302 // global dynamic symbol, and DYNCOUNT is the number of global
1303 // dynamic symbols. This records the parameters, and returns the
1304 // new file offset. It updates *PLOCAL_SYMCOUNT if it created any
1305 // local symbols.
1306 off_t
1307 finalize(off_t off, off_t dynoff, size_t dyn_global_index, size_t dyncount,
1308 Stringpool* pool, unsigned int *plocal_symcount);
1310 // Write out the global symbols.
1311 void
1312 write_globals(const Input_objects*, const Stringpool*, const Stringpool*,
1313 Output_symtab_xindex*, Output_symtab_xindex*,
1314 Output_file*) const;
1316 // Write out a section symbol. Return the updated offset.
1317 void
1318 write_section_symbol(const Output_section*, Output_symtab_xindex*,
1319 Output_file*, off_t) const;
1321 // Dump statistical information to stderr.
1322 void
1323 print_stats() const;
1325 // Return the version script information.
1326 const Version_script_info&
1327 version_script() const
1328 { return version_script_; }
1330 private:
1331 Symbol_table(const Symbol_table&);
1332 Symbol_table& operator=(const Symbol_table&);
1334 // The type of the list of common symbols.
1335 typedef std::vector<Symbol*> Commons_type;
1337 // Make FROM a forwarder symbol to TO.
1338 void
1339 make_forwarder(Symbol* from, Symbol* to);
1341 // Add a symbol.
1342 template<int size, bool big_endian>
1343 Sized_symbol<size>*
1344 add_from_object(Object*, const char *name, Stringpool::Key name_key,
1345 const char *version, Stringpool::Key version_key,
1346 bool def, const elfcpp::Sym<size, big_endian>& sym,
1347 unsigned int st_shndx, bool is_ordinary,
1348 unsigned int orig_st_shndx);
1350 // Resolve symbols.
1351 template<int size, bool big_endian>
1352 void
1353 resolve(Sized_symbol<size>* to,
1354 const elfcpp::Sym<size, big_endian>& sym,
1355 unsigned int st_shndx, bool is_ordinary,
1356 unsigned int orig_st_shndx,
1357 Object*, const char* version);
1359 template<int size, bool big_endian>
1360 void
1361 resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from);
1363 // Record that a symbol is forced to be local by a version script.
1364 void
1365 force_local(Symbol*);
1367 // Adjust NAME and *NAME_KEY for wrapping.
1368 const char*
1369 wrap_symbol(Object* object, const char*, Stringpool::Key* name_key);
1371 // Whether we should override a symbol, based on flags in
1372 // resolve.cc.
1373 static bool
1374 should_override(const Symbol*, unsigned int, Object*, bool*);
1376 // Override a symbol.
1377 template<int size, bool big_endian>
1378 void
1379 override(Sized_symbol<size>* tosym,
1380 const elfcpp::Sym<size, big_endian>& fromsym,
1381 unsigned int st_shndx, bool is_ordinary,
1382 Object* object, const char* version);
1384 // Whether we should override a symbol with a special symbol which
1385 // is automatically defined by the linker.
1386 static bool
1387 should_override_with_special(const Symbol*);
1389 // Override a symbol with a special symbol.
1390 template<int size>
1391 void
1392 override_with_special(Sized_symbol<size>* tosym,
1393 const Sized_symbol<size>* fromsym);
1395 // Record all weak alias sets for a dynamic object.
1396 template<int size>
1397 void
1398 record_weak_aliases(std::vector<Sized_symbol<size>*>*);
1400 // Define a special symbol.
1401 template<int size, bool big_endian>
1402 Sized_symbol<size>*
1403 define_special_symbol(const char** pname, const char** pversion,
1404 bool only_if_ref, Sized_symbol<size>** poldsym);
1406 // Define a symbol in an Output_data, sized version.
1407 template<int size>
1408 Sized_symbol<size>*
1409 do_define_in_output_data(const char* name, const char* version, Output_data*,
1410 typename elfcpp::Elf_types<size>::Elf_Addr value,
1411 typename elfcpp::Elf_types<size>::Elf_WXword ssize,
1412 elfcpp::STT type, elfcpp::STB binding,
1413 elfcpp::STV visibility, unsigned char nonvis,
1414 bool offset_is_from_end, bool only_if_ref);
1416 // Define a symbol in an Output_segment, sized version.
1417 template<int size>
1418 Sized_symbol<size>*
1419 do_define_in_output_segment(
1420 const char* name, const char* version, Output_segment* os,
1421 typename elfcpp::Elf_types<size>::Elf_Addr value,
1422 typename elfcpp::Elf_types<size>::Elf_WXword ssize,
1423 elfcpp::STT type, elfcpp::STB binding,
1424 elfcpp::STV visibility, unsigned char nonvis,
1425 Symbol::Segment_offset_base offset_base, bool only_if_ref);
1427 // Define a symbol as a constant, sized version.
1428 template<int size>
1429 Sized_symbol<size>*
1430 do_define_as_constant(
1431 const char* name, const char* version,
1432 typename elfcpp::Elf_types<size>::Elf_Addr value,
1433 typename elfcpp::Elf_types<size>::Elf_WXword ssize,
1434 elfcpp::STT type, elfcpp::STB binding,
1435 elfcpp::STV visibility, unsigned char nonvis,
1436 bool only_if_ref, bool force_override);
1438 // Add any undefined symbols named on the command line to the symbol
1439 // table, sized version.
1440 template<int size>
1441 void
1442 do_add_undefined_symbols_from_command_line();
1444 // Allocate the common symbols, sized version.
1445 template<int size>
1446 void
1447 do_allocate_commons(Layout*, Mapfile*);
1449 // Allocate the common symbols from one list.
1450 template<int size>
1451 void
1452 do_allocate_commons_list(Layout*, bool is_tls, Commons_type*, Mapfile*);
1454 // Implement detect_odr_violations.
1455 template<int size, bool big_endian>
1456 void
1457 sized_detect_odr_violations() const;
1459 // Finalize symbols specialized for size.
1460 template<int size>
1461 off_t
1462 sized_finalize(off_t, Stringpool*, unsigned int*);
1464 // Finalize a symbol. Return whether it should be added to the
1465 // symbol table.
1466 template<int size>
1467 bool
1468 sized_finalize_symbol(Symbol*);
1470 // Add a symbol the final symtab by setting its index.
1471 template<int size>
1472 void
1473 add_to_final_symtab(Symbol*, Stringpool*, unsigned int* pindex, off_t* poff);
1475 // Write globals specialized for size and endianness.
1476 template<int size, bool big_endian>
1477 void
1478 sized_write_globals(const Input_objects*, const Stringpool*,
1479 const Stringpool*, Output_symtab_xindex*,
1480 Output_symtab_xindex*, Output_file*) const;
1482 // Write out a symbol to P.
1483 template<int size, bool big_endian>
1484 void
1485 sized_write_symbol(Sized_symbol<size>*,
1486 typename elfcpp::Elf_types<size>::Elf_Addr value,
1487 unsigned int shndx,
1488 const Stringpool*, unsigned char* p) const;
1490 // Possibly warn about an undefined symbol from a dynamic object.
1491 void
1492 warn_about_undefined_dynobj_symbol(const Input_objects*, Symbol*) const;
1494 // Write out a section symbol, specialized for size and endianness.
1495 template<int size, bool big_endian>
1496 void
1497 sized_write_section_symbol(const Output_section*, Output_symtab_xindex*,
1498 Output_file*, off_t) const;
1500 // The type of the symbol hash table.
1502 typedef std::pair<Stringpool::Key, Stringpool::Key> Symbol_table_key;
1504 struct Symbol_table_hash
1506 size_t
1507 operator()(const Symbol_table_key&) const;
1510 struct Symbol_table_eq
1512 bool
1513 operator()(const Symbol_table_key&, const Symbol_table_key&) const;
1516 typedef Unordered_map<Symbol_table_key, Symbol*, Symbol_table_hash,
1517 Symbol_table_eq> Symbol_table_type;
1519 // The type of the list of symbols which have been forced local.
1520 typedef std::vector<Symbol*> Forced_locals;
1522 // A map from symbols with COPY relocs to the dynamic objects where
1523 // they are defined.
1524 typedef Unordered_map<const Symbol*, Dynobj*> Copied_symbol_dynobjs;
1526 // A map from symbol name (as a pointer into the namepool) to all
1527 // the locations the symbols is (weakly) defined (and certain other
1528 // conditions are met). This map will be used later to detect
1529 // possible One Definition Rule (ODR) violations.
1530 struct Symbol_location
1532 Object* object; // Object where the symbol is defined.
1533 unsigned int shndx; // Section-in-object where the symbol is defined.
1534 off_t offset; // Offset-in-section where the symbol is defined.
1535 bool operator==(const Symbol_location& that) const
1537 return (this->object == that.object
1538 && this->shndx == that.shndx
1539 && this->offset == that.offset);
1543 struct Symbol_location_hash
1545 size_t operator()(const Symbol_location& loc) const
1546 { return reinterpret_cast<uintptr_t>(loc.object) ^ loc.offset ^ loc.shndx; }
1549 typedef Unordered_map<const char*,
1550 Unordered_set<Symbol_location, Symbol_location_hash> >
1551 Odr_map;
1553 // We increment this every time we see a new undefined symbol, for
1554 // use in archive groups.
1555 int saw_undefined_;
1556 // The index of the first global symbol in the output file.
1557 unsigned int first_global_index_;
1558 // The file offset within the output symtab section where we should
1559 // write the table.
1560 off_t offset_;
1561 // The number of global symbols we want to write out.
1562 unsigned int output_count_;
1563 // The file offset of the global dynamic symbols, or 0 if none.
1564 off_t dynamic_offset_;
1565 // The index of the first global dynamic symbol.
1566 unsigned int first_dynamic_global_index_;
1567 // The number of global dynamic symbols, or 0 if none.
1568 unsigned int dynamic_count_;
1569 // The symbol hash table.
1570 Symbol_table_type table_;
1571 // A pool of symbol names. This is used for all global symbols.
1572 // Entries in the hash table point into this pool.
1573 Stringpool namepool_;
1574 // Forwarding symbols.
1575 Unordered_map<const Symbol*, Symbol*> forwarders_;
1576 // Weak aliases. A symbol in this list points to the next alias.
1577 // The aliases point to each other in a circular list.
1578 Unordered_map<Symbol*, Symbol*> weak_aliases_;
1579 // We don't expect there to be very many common symbols, so we keep
1580 // a list of them. When we find a common symbol we add it to this
1581 // list. It is possible that by the time we process the list the
1582 // symbol is no longer a common symbol. It may also have become a
1583 // forwarder.
1584 Commons_type commons_;
1585 // This is like the commons_ field, except that it holds TLS common
1586 // symbols.
1587 Commons_type tls_commons_;
1588 // A list of symbols which have been forced to be local. We don't
1589 // expect there to be very many of them, so we keep a list of them
1590 // rather than walking the whole table to find them.
1591 Forced_locals forced_locals_;
1592 // Manage symbol warnings.
1593 Warnings warnings_;
1594 // Manage potential One Definition Rule (ODR) violations.
1595 Odr_map candidate_odr_violations_;
1597 // When we emit a COPY reloc for a symbol, we define it in an
1598 // Output_data. When it's time to emit version information for it,
1599 // we need to know the dynamic object in which we found the original
1600 // definition. This maps symbols with COPY relocs to the dynamic
1601 // object where they were defined.
1602 Copied_symbol_dynobjs copied_symbol_dynobjs_;
1603 // Information parsed from the version script, if any.
1604 const Version_script_info& version_script_;
1607 // We inline get_sized_symbol for efficiency.
1609 template<int size>
1610 Sized_symbol<size>*
1611 Symbol_table::get_sized_symbol(Symbol* sym) const
1613 gold_assert(size == parameters->target().get_size());
1614 return static_cast<Sized_symbol<size>*>(sym);
1617 template<int size>
1618 const Sized_symbol<size>*
1619 Symbol_table::get_sized_symbol(const Symbol* sym) const
1621 gold_assert(size == parameters->target().get_size());
1622 return static_cast<const Sized_symbol<size>*>(sym);
1625 } // End namespace gold.
1627 #endif // !defined(GOLD_SYMTAB_H)