1 // symtab.cc -- the gold symbol table
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.
34 #include "dwarf_reader.h"
38 #include "workqueue.h"
46 // Initialize fields in Symbol. This initializes everything except u_
50 Symbol::init_fields(const char* name, const char* version,
51 elfcpp::STT type, elfcpp::STB binding,
52 elfcpp::STV visibility, unsigned char nonvis)
55 this->version_ = version;
56 this->symtab_index_ = 0;
57 this->dynsym_index_ = 0;
58 this->got_offsets_.init();
59 this->plt_offset_ = 0;
61 this->binding_ = binding;
62 this->visibility_ = visibility;
63 this->nonvis_ = nonvis;
64 this->is_target_special_ = false;
65 this->is_def_ = false;
66 this->is_forwarder_ = false;
67 this->has_alias_ = false;
68 this->needs_dynsym_entry_ = false;
69 this->in_reg_ = false;
70 this->in_dyn_ = false;
71 this->has_plt_offset_ = false;
72 this->has_warning_ = false;
73 this->is_copied_from_dynobj_ = false;
74 this->is_forced_local_ = false;
77 // Return the demangled version of the symbol's name, but only
78 // if the --demangle flag was set.
81 demangle(const char* name)
83 if (!parameters->options().do_demangle())
86 // cplus_demangle allocates memory for the result it returns,
87 // and returns NULL if the name is already demangled.
88 char* demangled_name = cplus_demangle(name, DMGL_ANSI | DMGL_PARAMS);
89 if (demangled_name == NULL)
92 std::string retval(demangled_name);
98 Symbol::demangled_name() const
100 return demangle(this->name());
103 // Initialize the fields in the base class Symbol for SYM in OBJECT.
105 template<int size, bool big_endian>
107 Symbol::init_base(const char* name, const char* version, Object* object,
108 const elfcpp::Sym<size, big_endian>& sym)
110 this->init_fields(name, version, sym.get_st_type(), sym.get_st_bind(),
111 sym.get_st_visibility(), sym.get_st_nonvis());
112 this->u_.from_object.object = object;
113 // FIXME: Handle SHN_XINDEX.
114 this->u_.from_object.shndx = sym.get_st_shndx();
115 this->source_ = FROM_OBJECT;
116 this->in_reg_ = !object->is_dynamic();
117 this->in_dyn_ = object->is_dynamic();
120 // Initialize the fields in the base class Symbol for a symbol defined
121 // in an Output_data.
124 Symbol::init_base(const char* name, Output_data* od, elfcpp::STT type,
125 elfcpp::STB binding, elfcpp::STV visibility,
126 unsigned char nonvis, bool offset_is_from_end)
128 this->init_fields(name, NULL, type, binding, visibility, nonvis);
129 this->u_.in_output_data.output_data = od;
130 this->u_.in_output_data.offset_is_from_end = offset_is_from_end;
131 this->source_ = IN_OUTPUT_DATA;
132 this->in_reg_ = true;
135 // Initialize the fields in the base class Symbol for a symbol defined
136 // in an Output_segment.
139 Symbol::init_base(const char* name, Output_segment* os, elfcpp::STT type,
140 elfcpp::STB binding, elfcpp::STV visibility,
141 unsigned char nonvis, Segment_offset_base offset_base)
143 this->init_fields(name, NULL, type, binding, visibility, nonvis);
144 this->u_.in_output_segment.output_segment = os;
145 this->u_.in_output_segment.offset_base = offset_base;
146 this->source_ = IN_OUTPUT_SEGMENT;
147 this->in_reg_ = true;
150 // Initialize the fields in the base class Symbol for a symbol defined
154 Symbol::init_base(const char* name, elfcpp::STT type,
155 elfcpp::STB binding, elfcpp::STV visibility,
156 unsigned char nonvis)
158 this->init_fields(name, NULL, type, binding, visibility, nonvis);
159 this->source_ = CONSTANT;
160 this->in_reg_ = true;
163 // Allocate a common symbol in the base.
166 Symbol::allocate_base_common(Output_data* od)
168 gold_assert(this->is_common());
169 this->source_ = IN_OUTPUT_DATA;
170 this->u_.in_output_data.output_data = od;
171 this->u_.in_output_data.offset_is_from_end = false;
174 // Initialize the fields in Sized_symbol for SYM in OBJECT.
177 template<bool big_endian>
179 Sized_symbol<size>::init(const char* name, const char* version, Object* object,
180 const elfcpp::Sym<size, big_endian>& sym)
182 this->init_base(name, version, object, sym);
183 this->value_ = sym.get_st_value();
184 this->symsize_ = sym.get_st_size();
187 // Initialize the fields in Sized_symbol for a symbol defined in an
192 Sized_symbol<size>::init(const char* name, Output_data* od,
193 Value_type value, Size_type symsize,
194 elfcpp::STT type, elfcpp::STB binding,
195 elfcpp::STV visibility, unsigned char nonvis,
196 bool offset_is_from_end)
198 this->init_base(name, od, type, binding, visibility, nonvis,
200 this->value_ = value;
201 this->symsize_ = symsize;
204 // Initialize the fields in Sized_symbol for a symbol defined in an
209 Sized_symbol<size>::init(const char* name, Output_segment* os,
210 Value_type value, Size_type symsize,
211 elfcpp::STT type, elfcpp::STB binding,
212 elfcpp::STV visibility, unsigned char nonvis,
213 Segment_offset_base offset_base)
215 this->init_base(name, os, type, binding, visibility, nonvis, offset_base);
216 this->value_ = value;
217 this->symsize_ = symsize;
220 // Initialize the fields in Sized_symbol for a symbol defined as a
225 Sized_symbol<size>::init(const char* name, Value_type value, Size_type symsize,
226 elfcpp::STT type, elfcpp::STB binding,
227 elfcpp::STV visibility, unsigned char nonvis)
229 this->init_base(name, type, binding, visibility, nonvis);
230 this->value_ = value;
231 this->symsize_ = symsize;
234 // Allocate a common symbol.
238 Sized_symbol<size>::allocate_common(Output_data* od, Value_type value)
240 this->allocate_base_common(od);
241 this->value_ = value;
244 // Return true if this symbol should be added to the dynamic symbol
248 Symbol::should_add_dynsym_entry() const
250 // If the symbol is used by a dynamic relocation, we need to add it.
251 if (this->needs_dynsym_entry())
254 // If the symbol was forced local in a version script, do not add it.
255 if (this->is_forced_local())
258 // If exporting all symbols or building a shared library,
259 // and the symbol is defined in a regular object and is
260 // externally visible, we need to add it.
261 if ((parameters->options().export_dynamic() || parameters->options().shared())
262 && !this->is_from_dynobj()
263 && this->is_externally_visible())
269 // Return true if the final value of this symbol is known at link
273 Symbol::final_value_is_known() const
275 // If we are not generating an executable, then no final values are
276 // known, since they will change at runtime.
277 if (parameters->options().shared() || parameters->options().relocatable())
280 // If the symbol is not from an object file, then it is defined, and
282 if (this->source_ != FROM_OBJECT)
285 // If the symbol is from a dynamic object, then the final value is
287 if (this->object()->is_dynamic())
290 // If the symbol is not undefined (it is defined or common), then
291 // the final value is known.
292 if (!this->is_undefined())
295 // If the symbol is undefined, then whether the final value is known
296 // depends on whether we are doing a static link. If we are doing a
297 // dynamic link, then the final value could be filled in at runtime.
298 // This could reasonably be the case for a weak undefined symbol.
299 return parameters->doing_static_link();
302 // Return the output section where this symbol is defined.
305 Symbol::output_section() const
307 switch (this->source_)
311 unsigned int shndx = this->u_.from_object.shndx;
312 if (shndx != elfcpp::SHN_UNDEF && shndx < elfcpp::SHN_LORESERVE)
314 gold_assert(!this->u_.from_object.object->is_dynamic());
315 Relobj* relobj = static_cast<Relobj*>(this->u_.from_object.object);
316 section_offset_type dummy;
317 return relobj->output_section(shndx, &dummy);
323 return this->u_.in_output_data.output_data->output_section();
325 case IN_OUTPUT_SEGMENT:
334 // Set the symbol's output section. This is used for symbols defined
335 // in scripts. This should only be called after the symbol table has
339 Symbol::set_output_section(Output_section* os)
341 switch (this->source_)
345 gold_assert(this->output_section() == os);
348 this->source_ = IN_OUTPUT_DATA;
349 this->u_.in_output_data.output_data = os;
350 this->u_.in_output_data.offset_is_from_end = false;
352 case IN_OUTPUT_SEGMENT:
358 // Class Symbol_table.
360 Symbol_table::Symbol_table(unsigned int count,
361 const Version_script_info& version_script)
362 : saw_undefined_(0), offset_(0), table_(count), namepool_(),
363 forwarders_(), commons_(), forced_locals_(), warnings_(),
364 version_script_(version_script)
366 namepool_.reserve(count);
369 Symbol_table::~Symbol_table()
373 // The hash function. The key values are Stringpool keys.
376 Symbol_table::Symbol_table_hash::operator()(const Symbol_table_key& key) const
378 return key.first ^ key.second;
381 // The symbol table key equality function. This is called with
385 Symbol_table::Symbol_table_eq::operator()(const Symbol_table_key& k1,
386 const Symbol_table_key& k2) const
388 return k1.first == k2.first && k1.second == k2.second;
391 // Make TO a symbol which forwards to FROM.
394 Symbol_table::make_forwarder(Symbol* from, Symbol* to)
396 gold_assert(from != to);
397 gold_assert(!from->is_forwarder() && !to->is_forwarder());
398 this->forwarders_[from] = to;
399 from->set_forwarder();
402 // Resolve the forwards from FROM, returning the real symbol.
405 Symbol_table::resolve_forwards(const Symbol* from) const
407 gold_assert(from->is_forwarder());
408 Unordered_map<const Symbol*, Symbol*>::const_iterator p =
409 this->forwarders_.find(from);
410 gold_assert(p != this->forwarders_.end());
414 // Look up a symbol by name.
417 Symbol_table::lookup(const char* name, const char* version) const
419 Stringpool::Key name_key;
420 name = this->namepool_.find(name, &name_key);
424 Stringpool::Key version_key = 0;
427 version = this->namepool_.find(version, &version_key);
432 Symbol_table_key key(name_key, version_key);
433 Symbol_table::Symbol_table_type::const_iterator p = this->table_.find(key);
434 if (p == this->table_.end())
439 // Resolve a Symbol with another Symbol. This is only used in the
440 // unusual case where there are references to both an unversioned
441 // symbol and a symbol with a version, and we then discover that that
442 // version is the default version. Because this is unusual, we do
443 // this the slow way, by converting back to an ELF symbol.
445 template<int size, bool big_endian>
447 Symbol_table::resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from,
450 unsigned char buf[elfcpp::Elf_sizes<size>::sym_size];
451 elfcpp::Sym_write<size, big_endian> esym(buf);
452 // We don't bother to set the st_name field.
453 esym.put_st_value(from->value());
454 esym.put_st_size(from->symsize());
455 esym.put_st_info(from->binding(), from->type());
456 esym.put_st_other(from->visibility(), from->nonvis());
457 esym.put_st_shndx(from->shndx());
458 this->resolve(to, esym.sym(), esym.sym(), from->object(), version);
465 // Record that a symbol is forced to be local by a version script.
468 Symbol_table::force_local(Symbol* sym)
470 if (!sym->is_defined() && !sym->is_common())
472 if (sym->is_forced_local())
474 // We already got this one.
477 sym->set_is_forced_local();
478 this->forced_locals_.push_back(sym);
481 // Add one symbol from OBJECT to the symbol table. NAME is symbol
482 // name and VERSION is the version; both are canonicalized. DEF is
483 // whether this is the default version.
485 // If DEF is true, then this is the definition of a default version of
486 // a symbol. That means that any lookup of NAME/NULL and any lookup
487 // of NAME/VERSION should always return the same symbol. This is
488 // obvious for references, but in particular we want to do this for
489 // definitions: overriding NAME/NULL should also override
490 // NAME/VERSION. If we don't do that, it would be very hard to
491 // override functions in a shared library which uses versioning.
493 // We implement this by simply making both entries in the hash table
494 // point to the same Symbol structure. That is easy enough if this is
495 // the first time we see NAME/NULL or NAME/VERSION, but it is possible
496 // that we have seen both already, in which case they will both have
497 // independent entries in the symbol table. We can't simply change
498 // the symbol table entry, because we have pointers to the entries
499 // attached to the object files. So we mark the entry attached to the
500 // object file as a forwarder, and record it in the forwarders_ map.
501 // Note that entries in the hash table will never be marked as
504 // SYM and ORIG_SYM are almost always the same. ORIG_SYM is the
505 // symbol exactly as it existed in the input file. SYM is usually
506 // that as well, but can be modified, for instance if we determine
507 // it's in a to-be-discarded section.
509 template<int size, bool big_endian>
511 Symbol_table::add_from_object(Object* object,
513 Stringpool::Key name_key,
515 Stringpool::Key version_key,
517 const elfcpp::Sym<size, big_endian>& sym,
518 const elfcpp::Sym<size, big_endian>& orig_sym)
520 Symbol* const snull = NULL;
521 std::pair<typename Symbol_table_type::iterator, bool> ins =
522 this->table_.insert(std::make_pair(std::make_pair(name_key, version_key),
525 std::pair<typename Symbol_table_type::iterator, bool> insdef =
526 std::make_pair(this->table_.end(), false);
529 const Stringpool::Key vnull_key = 0;
530 insdef = this->table_.insert(std::make_pair(std::make_pair(name_key,
535 // ins.first: an iterator, which is a pointer to a pair.
536 // ins.first->first: the key (a pair of name and version).
537 // ins.first->second: the value (Symbol*).
538 // ins.second: true if new entry was inserted, false if not.
540 Sized_symbol<size>* ret;
545 // We already have an entry for NAME/VERSION.
546 ret = this->get_sized_symbol<size>(ins.first->second);
547 gold_assert(ret != NULL);
549 was_undefined = ret->is_undefined();
550 was_common = ret->is_common();
552 this->resolve(ret, sym, orig_sym, object, version);
558 // This is the first time we have seen NAME/NULL. Make
559 // NAME/NULL point to NAME/VERSION.
560 insdef.first->second = ret;
562 else if (insdef.first->second != ret
563 && insdef.first->second->is_undefined())
565 // This is the unfortunate case where we already have
566 // entries for both NAME/VERSION and NAME/NULL. Note
567 // that we don't want to combine them if the existing
568 // symbol is going to override the new one. FIXME: We
569 // currently just test is_undefined, but this may not do
570 // the right thing if the existing symbol is from a
571 // shared library and the new one is from a regular
574 const Sized_symbol<size>* sym2;
575 sym2 = this->get_sized_symbol<size>(insdef.first->second);
576 Symbol_table::resolve<size, big_endian>(ret, sym2, version);
577 this->make_forwarder(insdef.first->second, ret);
578 insdef.first->second = ret;
584 // This is the first time we have seen NAME/VERSION.
585 gold_assert(ins.first->second == NULL);
587 was_undefined = false;
590 if (def && !insdef.second)
592 // We already have an entry for NAME/NULL. If we override
593 // it, then change it to NAME/VERSION.
594 ret = this->get_sized_symbol<size>(insdef.first->second);
595 this->resolve(ret, sym, orig_sym, object, version);
596 ins.first->second = ret;
600 Sized_target<size, big_endian>* target =
601 object->sized_target<size, big_endian>();
602 if (!target->has_make_symbol())
603 ret = new Sized_symbol<size>();
606 ret = target->make_symbol();
609 // This means that we don't want a symbol table
612 this->table_.erase(ins.first);
615 this->table_.erase(insdef.first);
616 // Inserting insdef invalidated ins.
617 this->table_.erase(std::make_pair(name_key,
624 ret->init(name, version, object, sym);
626 ins.first->second = ret;
629 // This is the first time we have seen NAME/NULL. Point
630 // it at the new entry for NAME/VERSION.
631 gold_assert(insdef.second);
632 insdef.first->second = ret;
637 // Record every time we see a new undefined symbol, to speed up
639 if (!was_undefined && ret->is_undefined())
640 ++this->saw_undefined_;
642 // Keep track of common symbols, to speed up common symbol
644 if (!was_common && ret->is_common())
645 this->commons_.push_back(ret);
648 ret->set_is_default();
652 // Add all the symbols in a relocatable object to the hash table.
654 template<int size, bool big_endian>
656 Symbol_table::add_from_relobj(
657 Sized_relobj<size, big_endian>* relobj,
658 const unsigned char* syms,
660 const char* sym_names,
661 size_t sym_name_size,
662 typename Sized_relobj<size, big_endian>::Symbols* sympointers)
664 gold_assert(size == relobj->target()->get_size());
665 gold_assert(size == parameters->target().get_size());
667 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
669 const bool just_symbols = relobj->just_symbols();
671 const unsigned char* p = syms;
672 for (size_t i = 0; i < count; ++i, p += sym_size)
674 elfcpp::Sym<size, big_endian> sym(p);
675 elfcpp::Sym<size, big_endian>* psym = &sym;
677 unsigned int st_name = psym->get_st_name();
678 if (st_name >= sym_name_size)
680 relobj->error(_("bad global symbol name offset %u at %zu"),
685 const char* name = sym_names + st_name;
687 // A symbol defined in a section which we are not including must
688 // be treated as an undefined symbol.
689 unsigned char symbuf[sym_size];
690 elfcpp::Sym<size, big_endian> sym2(symbuf);
691 unsigned int st_shndx = psym->get_st_shndx();
692 if (st_shndx != elfcpp::SHN_UNDEF
693 && st_shndx < elfcpp::SHN_LORESERVE
694 && !relobj->is_section_included(st_shndx))
696 memcpy(symbuf, p, sym_size);
697 elfcpp::Sym_write<size, big_endian> sw(symbuf);
698 sw.put_st_shndx(elfcpp::SHN_UNDEF);
702 // In an object file, an '@' in the name separates the symbol
703 // name from the version name. If there are two '@' characters,
704 // this is the default version.
705 const char* ver = strchr(name, '@');
707 // DEF: is the version default? LOCAL: is the symbol forced local?
713 // The symbol name is of the form foo@VERSION or foo@@VERSION
714 namelen = ver - name;
722 else if (!version_script_.empty())
724 // The symbol name did not have a version, but
725 // the version script may assign a version anyway.
726 namelen = strlen(name);
728 // Check the global: entries from the version script.
729 const std::string& version =
730 version_script_.get_symbol_version(name);
731 if (!version.empty())
732 ver = version.c_str();
733 // Check the local: entries from the version script
734 if (version_script_.symbol_is_local(name))
741 memcpy(symbuf, p, sym_size);
742 elfcpp::Sym_write<size, big_endian> sw(symbuf);
743 sw.put_st_shndx(elfcpp::SHN_ABS);
744 if (st_shndx != elfcpp::SHN_UNDEF
745 && st_shndx < elfcpp::SHN_LORESERVE)
747 // Symbol values in object files are section relative.
748 // This is normally what we want, but since here we are
749 // converting the symbol to absolute we need to add the
750 // section address. The section address in an object
751 // file is normally zero, but people can use a linker
752 // script to change it.
753 sw.put_st_value(sym2.get_st_value()
754 + relobj->section_address(st_shndx));
759 Sized_symbol<size>* res;
762 Stringpool::Key name_key;
763 name = this->namepool_.add(name, true, &name_key);
764 res = this->add_from_object(relobj, name, name_key, NULL, 0,
767 this->force_local(res);
771 Stringpool::Key name_key;
772 name = this->namepool_.add_with_length(name, namelen, true,
774 Stringpool::Key ver_key;
775 ver = this->namepool_.add(ver, true, &ver_key);
777 res = this->add_from_object(relobj, name, name_key, ver, ver_key,
781 (*sympointers)[i] = res;
785 // Add all the symbols in a dynamic object to the hash table.
787 template<int size, bool big_endian>
789 Symbol_table::add_from_dynobj(
790 Sized_dynobj<size, big_endian>* dynobj,
791 const unsigned char* syms,
793 const char* sym_names,
794 size_t sym_name_size,
795 const unsigned char* versym,
797 const std::vector<const char*>* version_map)
799 gold_assert(size == dynobj->target()->get_size());
800 gold_assert(size == parameters->target().get_size());
802 if (dynobj->just_symbols())
804 gold_error(_("--just-symbols does not make sense with a shared object"));
808 if (versym != NULL && versym_size / 2 < count)
810 dynobj->error(_("too few symbol versions"));
814 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
816 // We keep a list of all STT_OBJECT symbols, so that we can resolve
817 // weak aliases. This is necessary because if the dynamic object
818 // provides the same variable under two names, one of which is a
819 // weak definition, and the regular object refers to the weak
820 // definition, we have to put both the weak definition and the
821 // strong definition into the dynamic symbol table. Given a weak
822 // definition, the only way that we can find the corresponding
823 // strong definition, if any, is to search the symbol table.
824 std::vector<Sized_symbol<size>*> object_symbols;
826 const unsigned char* p = syms;
827 const unsigned char* vs = versym;
828 for (size_t i = 0; i < count; ++i, p += sym_size, vs += 2)
830 elfcpp::Sym<size, big_endian> sym(p);
832 // Ignore symbols with local binding or that have
833 // internal or hidden visibility.
834 if (sym.get_st_bind() == elfcpp::STB_LOCAL
835 || sym.get_st_visibility() == elfcpp::STV_INTERNAL
836 || sym.get_st_visibility() == elfcpp::STV_HIDDEN)
839 unsigned int st_name = sym.get_st_name();
840 if (st_name >= sym_name_size)
842 dynobj->error(_("bad symbol name offset %u at %zu"),
847 const char* name = sym_names + st_name;
849 Sized_symbol<size>* res;
853 Stringpool::Key name_key;
854 name = this->namepool_.add(name, true, &name_key);
855 res = this->add_from_object(dynobj, name, name_key, NULL, 0,
860 // Read the version information.
862 unsigned int v = elfcpp::Swap<16, big_endian>::readval(vs);
864 bool hidden = (v & elfcpp::VERSYM_HIDDEN) != 0;
865 v &= elfcpp::VERSYM_VERSION;
867 // The Sun documentation says that V can be VER_NDX_LOCAL,
868 // or VER_NDX_GLOBAL, or a version index. The meaning of
869 // VER_NDX_LOCAL is defined as "Symbol has local scope."
870 // The old GNU linker will happily generate VER_NDX_LOCAL
871 // for an undefined symbol. I don't know what the Sun
872 // linker will generate.
874 if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
875 && sym.get_st_shndx() != elfcpp::SHN_UNDEF)
877 // This symbol should not be visible outside the object.
881 // At this point we are definitely going to add this symbol.
882 Stringpool::Key name_key;
883 name = this->namepool_.add(name, true, &name_key);
885 if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
886 || v == static_cast<unsigned int>(elfcpp::VER_NDX_GLOBAL))
888 // This symbol does not have a version.
889 res = this->add_from_object(dynobj, name, name_key, NULL, 0,
894 if (v >= version_map->size())
896 dynobj->error(_("versym for symbol %zu out of range: %u"),
901 const char* version = (*version_map)[v];
904 dynobj->error(_("versym for symbol %zu has no name: %u"),
909 Stringpool::Key version_key;
910 version = this->namepool_.add(version, true, &version_key);
912 // If this is an absolute symbol, and the version name
913 // and symbol name are the same, then this is the
914 // version definition symbol. These symbols exist to
915 // support using -u to pull in particular versions. We
916 // do not want to record a version for them.
917 if (sym.get_st_shndx() == elfcpp::SHN_ABS
918 && name_key == version_key)
919 res = this->add_from_object(dynobj, name, name_key, NULL, 0,
923 const bool def = (!hidden
924 && (sym.get_st_shndx()
925 != elfcpp::SHN_UNDEF));
926 res = this->add_from_object(dynobj, name, name_key, version,
927 version_key, def, sym, sym);
932 if (sym.get_st_shndx() != elfcpp::SHN_UNDEF
933 && sym.get_st_type() == elfcpp::STT_OBJECT)
934 object_symbols.push_back(res);
937 this->record_weak_aliases(&object_symbols);
940 // This is used to sort weak aliases. We sort them first by section
941 // index, then by offset, then by weak ahead of strong.
944 class Weak_alias_sorter
947 bool operator()(const Sized_symbol<size>*, const Sized_symbol<size>*) const;
952 Weak_alias_sorter<size>::operator()(const Sized_symbol<size>* s1,
953 const Sized_symbol<size>* s2) const
955 if (s1->shndx() != s2->shndx())
956 return s1->shndx() < s2->shndx();
957 if (s1->value() != s2->value())
958 return s1->value() < s2->value();
959 if (s1->binding() != s2->binding())
961 if (s1->binding() == elfcpp::STB_WEAK)
963 if (s2->binding() == elfcpp::STB_WEAK)
966 return std::string(s1->name()) < std::string(s2->name());
969 // SYMBOLS is a list of object symbols from a dynamic object. Look
970 // for any weak aliases, and record them so that if we add the weak
971 // alias to the dynamic symbol table, we also add the corresponding
976 Symbol_table::record_weak_aliases(std::vector<Sized_symbol<size>*>* symbols)
978 // Sort the vector by section index, then by offset, then by weak
980 std::sort(symbols->begin(), symbols->end(), Weak_alias_sorter<size>());
982 // Walk through the vector. For each weak definition, record
984 for (typename std::vector<Sized_symbol<size>*>::const_iterator p =
989 if ((*p)->binding() != elfcpp::STB_WEAK)
992 // Build a circular list of weak aliases. Each symbol points to
993 // the next one in the circular list.
995 Sized_symbol<size>* from_sym = *p;
996 typename std::vector<Sized_symbol<size>*>::const_iterator q;
997 for (q = p + 1; q != symbols->end(); ++q)
999 if ((*q)->shndx() != from_sym->shndx()
1000 || (*q)->value() != from_sym->value())
1003 this->weak_aliases_[from_sym] = *q;
1004 from_sym->set_has_alias();
1010 this->weak_aliases_[from_sym] = *p;
1011 from_sym->set_has_alias();
1018 // Create and return a specially defined symbol. If ONLY_IF_REF is
1019 // true, then only create the symbol if there is a reference to it.
1020 // If this does not return NULL, it sets *POLDSYM to the existing
1021 // symbol if there is one. This canonicalizes *PNAME and *PVERSION.
1023 template<int size, bool big_endian>
1025 Symbol_table::define_special_symbol(const char** pname, const char** pversion,
1027 Sized_symbol<size>** poldsym)
1030 Sized_symbol<size>* sym;
1031 bool add_to_table = false;
1032 typename Symbol_table_type::iterator add_loc = this->table_.end();
1034 // If the caller didn't give us a version, see if we get one from
1035 // the version script.
1036 if (*pversion == NULL)
1038 const std::string& v(this->version_script_.get_symbol_version(*pname));
1040 *pversion = v.c_str();
1045 oldsym = this->lookup(*pname, *pversion);
1046 if (oldsym == NULL || !oldsym->is_undefined())
1049 *pname = oldsym->name();
1050 *pversion = oldsym->version();
1054 // Canonicalize NAME and VERSION.
1055 Stringpool::Key name_key;
1056 *pname = this->namepool_.add(*pname, true, &name_key);
1058 Stringpool::Key version_key = 0;
1059 if (*pversion != NULL)
1060 *pversion = this->namepool_.add(*pversion, true, &version_key);
1062 Symbol* const snull = NULL;
1063 std::pair<typename Symbol_table_type::iterator, bool> ins =
1064 this->table_.insert(std::make_pair(std::make_pair(name_key,
1070 // We already have a symbol table entry for NAME/VERSION.
1071 oldsym = ins.first->second;
1072 gold_assert(oldsym != NULL);
1076 // We haven't seen this symbol before.
1077 gold_assert(ins.first->second == NULL);
1078 add_to_table = true;
1079 add_loc = ins.first;
1084 const Target& target = parameters->target();
1085 if (!target.has_make_symbol())
1086 sym = new Sized_symbol<size>();
1089 gold_assert(target.get_size() == size);
1090 gold_assert(target.is_big_endian() ? big_endian : !big_endian);
1091 typedef Sized_target<size, big_endian> My_target;
1092 const My_target* sized_target =
1093 static_cast<const My_target*>(&target);
1094 sym = sized_target->make_symbol();
1100 add_loc->second = sym;
1102 gold_assert(oldsym != NULL);
1104 *poldsym = this->get_sized_symbol<size>(oldsym);
1109 // Define a symbol based on an Output_data.
1112 Symbol_table::define_in_output_data(const char* name,
1113 const char* version,
1118 elfcpp::STB binding,
1119 elfcpp::STV visibility,
1120 unsigned char nonvis,
1121 bool offset_is_from_end,
1124 if (parameters->target().get_size() == 32)
1126 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1127 return this->do_define_in_output_data<32>(name, version, od,
1128 value, symsize, type, binding,
1136 else if (parameters->target().get_size() == 64)
1138 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1139 return this->do_define_in_output_data<64>(name, version, od,
1140 value, symsize, type, binding,
1152 // Define a symbol in an Output_data, sized version.
1156 Symbol_table::do_define_in_output_data(
1158 const char* version,
1160 typename elfcpp::Elf_types<size>::Elf_Addr value,
1161 typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1163 elfcpp::STB binding,
1164 elfcpp::STV visibility,
1165 unsigned char nonvis,
1166 bool offset_is_from_end,
1169 Sized_symbol<size>* sym;
1170 Sized_symbol<size>* oldsym;
1172 if (parameters->target().is_big_endian())
1174 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1175 sym = this->define_special_symbol<size, true>(&name, &version,
1176 only_if_ref, &oldsym);
1183 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1184 sym = this->define_special_symbol<size, false>(&name, &version,
1185 only_if_ref, &oldsym);
1194 gold_assert(version == NULL || oldsym != NULL);
1195 sym->init(name, od, value, symsize, type, binding, visibility, nonvis,
1196 offset_is_from_end);
1200 if (binding == elfcpp::STB_LOCAL
1201 || this->version_script_.symbol_is_local(name))
1202 this->force_local(sym);
1206 if (Symbol_table::should_override_with_special(oldsym))
1207 this->override_with_special(oldsym, sym);
1212 // Define a symbol based on an Output_segment.
1215 Symbol_table::define_in_output_segment(const char* name,
1216 const char* version, Output_segment* os,
1220 elfcpp::STB binding,
1221 elfcpp::STV visibility,
1222 unsigned char nonvis,
1223 Symbol::Segment_offset_base offset_base,
1226 if (parameters->target().get_size() == 32)
1228 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1229 return this->do_define_in_output_segment<32>(name, version, os,
1230 value, symsize, type,
1231 binding, visibility, nonvis,
1232 offset_base, only_if_ref);
1237 else if (parameters->target().get_size() == 64)
1239 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1240 return this->do_define_in_output_segment<64>(name, version, os,
1241 value, symsize, type,
1242 binding, visibility, nonvis,
1243 offset_base, only_if_ref);
1252 // Define a symbol in an Output_segment, sized version.
1256 Symbol_table::do_define_in_output_segment(
1258 const char* version,
1260 typename elfcpp::Elf_types<size>::Elf_Addr value,
1261 typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1263 elfcpp::STB binding,
1264 elfcpp::STV visibility,
1265 unsigned char nonvis,
1266 Symbol::Segment_offset_base offset_base,
1269 Sized_symbol<size>* sym;
1270 Sized_symbol<size>* oldsym;
1272 if (parameters->target().is_big_endian())
1274 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1275 sym = this->define_special_symbol<size, true>(&name, &version,
1276 only_if_ref, &oldsym);
1283 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1284 sym = this->define_special_symbol<size, false>(&name, &version,
1285 only_if_ref, &oldsym);
1294 gold_assert(version == NULL || oldsym != NULL);
1295 sym->init(name, os, value, symsize, type, binding, visibility, nonvis,
1300 if (binding == elfcpp::STB_LOCAL
1301 || this->version_script_.symbol_is_local(name))
1302 this->force_local(sym);
1306 if (Symbol_table::should_override_with_special(oldsym))
1307 this->override_with_special(oldsym, sym);
1312 // Define a special symbol with a constant value. It is a multiple
1313 // definition error if this symbol is already defined.
1316 Symbol_table::define_as_constant(const char* name,
1317 const char* version,
1321 elfcpp::STB binding,
1322 elfcpp::STV visibility,
1323 unsigned char nonvis,
1325 bool force_override)
1327 if (parameters->target().get_size() == 32)
1329 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1330 return this->do_define_as_constant<32>(name, version, value,
1331 symsize, type, binding,
1332 visibility, nonvis, only_if_ref,
1338 else if (parameters->target().get_size() == 64)
1340 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1341 return this->do_define_as_constant<64>(name, version, value,
1342 symsize, type, binding,
1343 visibility, nonvis, only_if_ref,
1353 // Define a symbol as a constant, sized version.
1357 Symbol_table::do_define_as_constant(
1359 const char* version,
1360 typename elfcpp::Elf_types<size>::Elf_Addr value,
1361 typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1363 elfcpp::STB binding,
1364 elfcpp::STV visibility,
1365 unsigned char nonvis,
1367 bool force_override)
1369 Sized_symbol<size>* sym;
1370 Sized_symbol<size>* oldsym;
1372 if (parameters->target().is_big_endian())
1374 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1375 sym = this->define_special_symbol<size, true>(&name, &version,
1376 only_if_ref, &oldsym);
1383 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1384 sym = this->define_special_symbol<size, false>(&name, &version,
1385 only_if_ref, &oldsym);
1394 gold_assert(version == NULL || version == name || oldsym != NULL);
1395 sym->init(name, value, symsize, type, binding, visibility, nonvis);
1399 if (binding == elfcpp::STB_LOCAL
1400 || this->version_script_.symbol_is_local(name))
1401 this->force_local(sym);
1405 if (force_override || Symbol_table::should_override_with_special(oldsym))
1406 this->override_with_special(oldsym, sym);
1411 // Define a set of symbols in output sections.
1414 Symbol_table::define_symbols(const Layout* layout, int count,
1415 const Define_symbol_in_section* p,
1418 for (int i = 0; i < count; ++i, ++p)
1420 Output_section* os = layout->find_output_section(p->output_section);
1422 this->define_in_output_data(p->name, NULL, os, p->value,
1423 p->size, p->type, p->binding,
1424 p->visibility, p->nonvis,
1425 p->offset_is_from_end,
1426 only_if_ref || p->only_if_ref);
1428 this->define_as_constant(p->name, NULL, 0, p->size, p->type,
1429 p->binding, p->visibility, p->nonvis,
1430 only_if_ref || p->only_if_ref,
1435 // Define a set of symbols in output segments.
1438 Symbol_table::define_symbols(const Layout* layout, int count,
1439 const Define_symbol_in_segment* p,
1442 for (int i = 0; i < count; ++i, ++p)
1444 Output_segment* os = layout->find_output_segment(p->segment_type,
1445 p->segment_flags_set,
1446 p->segment_flags_clear);
1448 this->define_in_output_segment(p->name, NULL, os, p->value,
1449 p->size, p->type, p->binding,
1450 p->visibility, p->nonvis,
1452 only_if_ref || p->only_if_ref);
1454 this->define_as_constant(p->name, NULL, 0, p->size, p->type,
1455 p->binding, p->visibility, p->nonvis,
1456 only_if_ref || p->only_if_ref,
1461 // Define CSYM using a COPY reloc. POSD is the Output_data where the
1462 // symbol should be defined--typically a .dyn.bss section. VALUE is
1463 // the offset within POSD.
1467 Symbol_table::define_with_copy_reloc(
1468 Sized_symbol<size>* csym,
1470 typename elfcpp::Elf_types<size>::Elf_Addr value)
1472 gold_assert(csym->is_from_dynobj());
1473 gold_assert(!csym->is_copied_from_dynobj());
1474 Object* object = csym->object();
1475 gold_assert(object->is_dynamic());
1476 Dynobj* dynobj = static_cast<Dynobj*>(object);
1478 // Our copied variable has to override any variable in a shared
1480 elfcpp::STB binding = csym->binding();
1481 if (binding == elfcpp::STB_WEAK)
1482 binding = elfcpp::STB_GLOBAL;
1484 this->define_in_output_data(csym->name(), csym->version(),
1485 posd, value, csym->symsize(),
1486 csym->type(), binding,
1487 csym->visibility(), csym->nonvis(),
1490 csym->set_is_copied_from_dynobj();
1491 csym->set_needs_dynsym_entry();
1493 this->copied_symbol_dynobjs_[csym] = dynobj;
1495 // We have now defined all aliases, but we have not entered them all
1496 // in the copied_symbol_dynobjs_ map.
1497 if (csym->has_alias())
1502 sym = this->weak_aliases_[sym];
1505 gold_assert(sym->output_data() == posd);
1507 sym->set_is_copied_from_dynobj();
1508 this->copied_symbol_dynobjs_[sym] = dynobj;
1513 // SYM is defined using a COPY reloc. Return the dynamic object where
1514 // the original definition was found.
1517 Symbol_table::get_copy_source(const Symbol* sym) const
1519 gold_assert(sym->is_copied_from_dynobj());
1520 Copied_symbol_dynobjs::const_iterator p =
1521 this->copied_symbol_dynobjs_.find(sym);
1522 gold_assert(p != this->copied_symbol_dynobjs_.end());
1526 // Set the dynamic symbol indexes. INDEX is the index of the first
1527 // global dynamic symbol. Pointers to the symbols are stored into the
1528 // vector SYMS. The names are added to DYNPOOL. This returns an
1529 // updated dynamic symbol index.
1532 Symbol_table::set_dynsym_indexes(unsigned int index,
1533 std::vector<Symbol*>* syms,
1534 Stringpool* dynpool,
1537 for (Symbol_table_type::iterator p = this->table_.begin();
1538 p != this->table_.end();
1541 Symbol* sym = p->second;
1543 // Note that SYM may already have a dynamic symbol index, since
1544 // some symbols appear more than once in the symbol table, with
1545 // and without a version.
1547 if (!sym->should_add_dynsym_entry())
1548 sym->set_dynsym_index(-1U);
1549 else if (!sym->has_dynsym_index())
1551 sym->set_dynsym_index(index);
1553 syms->push_back(sym);
1554 dynpool->add(sym->name(), false, NULL);
1556 // Record any version information.
1557 if (sym->version() != NULL)
1558 versions->record_version(this, dynpool, sym);
1562 // Finish up the versions. In some cases this may add new dynamic
1564 index = versions->finalize(this, index, syms);
1569 // Set the final values for all the symbols. The index of the first
1570 // global symbol in the output file is *PLOCAL_SYMCOUNT. Record the
1571 // file offset OFF. Add their names to POOL. Return the new file
1572 // offset. Update *PLOCAL_SYMCOUNT if necessary.
1575 Symbol_table::finalize(off_t off, off_t dynoff, size_t dyn_global_index,
1576 size_t dyncount, Stringpool* pool,
1577 unsigned int *plocal_symcount)
1581 gold_assert(*plocal_symcount != 0);
1582 this->first_global_index_ = *plocal_symcount;
1584 this->dynamic_offset_ = dynoff;
1585 this->first_dynamic_global_index_ = dyn_global_index;
1586 this->dynamic_count_ = dyncount;
1588 if (parameters->target().get_size() == 32)
1590 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_32_LITTLE)
1591 ret = this->sized_finalize<32>(off, pool, plocal_symcount);
1596 else if (parameters->target().get_size() == 64)
1598 #if defined(HAVE_TARGET_64_BIG) || defined(HAVE_TARGET_64_LITTLE)
1599 ret = this->sized_finalize<64>(off, pool, plocal_symcount);
1607 // Now that we have the final symbol table, we can reliably note
1608 // which symbols should get warnings.
1609 this->warnings_.note_warnings(this);
1614 // SYM is going into the symbol table at *PINDEX. Add the name to
1615 // POOL, update *PINDEX and *POFF.
1619 Symbol_table::add_to_final_symtab(Symbol* sym, Stringpool* pool,
1620 unsigned int* pindex, off_t* poff)
1622 sym->set_symtab_index(*pindex);
1623 pool->add(sym->name(), false, NULL);
1625 *poff += elfcpp::Elf_sizes<size>::sym_size;
1628 // Set the final value for all the symbols. This is called after
1629 // Layout::finalize, so all the output sections have their final
1634 Symbol_table::sized_finalize(off_t off, Stringpool* pool,
1635 unsigned int* plocal_symcount)
1637 off = align_address(off, size >> 3);
1638 this->offset_ = off;
1640 unsigned int index = *plocal_symcount;
1641 const unsigned int orig_index = index;
1643 // First do all the symbols which have been forced to be local, as
1644 // they must appear before all global symbols.
1645 for (Forced_locals::iterator p = this->forced_locals_.begin();
1646 p != this->forced_locals_.end();
1650 gold_assert(sym->is_forced_local());
1651 if (this->sized_finalize_symbol<size>(sym))
1653 this->add_to_final_symtab<size>(sym, pool, &index, &off);
1658 // Now do all the remaining symbols.
1659 for (Symbol_table_type::iterator p = this->table_.begin();
1660 p != this->table_.end();
1663 Symbol* sym = p->second;
1664 if (this->sized_finalize_symbol<size>(sym))
1665 this->add_to_final_symtab<size>(sym, pool, &index, &off);
1668 this->output_count_ = index - orig_index;
1673 // Finalize the symbol SYM. This returns true if the symbol should be
1674 // added to the symbol table, false otherwise.
1678 Symbol_table::sized_finalize_symbol(Symbol* unsized_sym)
1680 Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(unsized_sym);
1682 // The default version of a symbol may appear twice in the symbol
1683 // table. We only need to finalize it once.
1684 if (sym->has_symtab_index())
1689 gold_assert(!sym->has_symtab_index());
1690 sym->set_symtab_index(-1U);
1691 gold_assert(sym->dynsym_index() == -1U);
1695 typename Sized_symbol<size>::Value_type value;
1697 switch (sym->source())
1699 case Symbol::FROM_OBJECT:
1701 unsigned int shndx = sym->shndx();
1703 // FIXME: We need some target specific support here.
1704 if (shndx >= elfcpp::SHN_LORESERVE
1705 && shndx != elfcpp::SHN_ABS
1706 && shndx != elfcpp::SHN_COMMON)
1708 gold_error(_("%s: unsupported symbol section 0x%x"),
1709 sym->demangled_name().c_str(), shndx);
1710 shndx = elfcpp::SHN_UNDEF;
1713 Object* symobj = sym->object();
1714 if (symobj->is_dynamic())
1717 shndx = elfcpp::SHN_UNDEF;
1719 else if (shndx == elfcpp::SHN_UNDEF)
1721 else if (shndx == elfcpp::SHN_ABS || shndx == elfcpp::SHN_COMMON)
1722 value = sym->value();
1725 Relobj* relobj = static_cast<Relobj*>(symobj);
1726 section_offset_type secoff;
1727 Output_section* os = relobj->output_section(shndx, &secoff);
1731 sym->set_symtab_index(-1U);
1732 gold_assert(sym->dynsym_index() == -1U);
1736 if (sym->type() == elfcpp::STT_TLS)
1737 value = sym->value() + os->tls_offset() + secoff;
1739 value = sym->value() + os->address() + secoff;
1744 case Symbol::IN_OUTPUT_DATA:
1746 Output_data* od = sym->output_data();
1747 value = sym->value() + od->address();
1748 if (sym->offset_is_from_end())
1749 value += od->data_size();
1753 case Symbol::IN_OUTPUT_SEGMENT:
1755 Output_segment* os = sym->output_segment();
1756 value = sym->value() + os->vaddr();
1757 switch (sym->offset_base())
1759 case Symbol::SEGMENT_START:
1761 case Symbol::SEGMENT_END:
1762 value += os->memsz();
1764 case Symbol::SEGMENT_BSS:
1765 value += os->filesz();
1773 case Symbol::CONSTANT:
1774 value = sym->value();
1781 sym->set_value(value);
1783 if (parameters->options().strip_all())
1785 sym->set_symtab_index(-1U);
1792 // Write out the global symbols.
1795 Symbol_table::write_globals(const Input_objects* input_objects,
1796 const Stringpool* sympool,
1797 const Stringpool* dynpool, Output_file* of) const
1799 switch (parameters->size_and_endianness())
1801 #ifdef HAVE_TARGET_32_LITTLE
1802 case Parameters::TARGET_32_LITTLE:
1803 this->sized_write_globals<32, false>(input_objects, sympool,
1807 #ifdef HAVE_TARGET_32_BIG
1808 case Parameters::TARGET_32_BIG:
1809 this->sized_write_globals<32, true>(input_objects, sympool,
1813 #ifdef HAVE_TARGET_64_LITTLE
1814 case Parameters::TARGET_64_LITTLE:
1815 this->sized_write_globals<64, false>(input_objects, sympool,
1819 #ifdef HAVE_TARGET_64_BIG
1820 case Parameters::TARGET_64_BIG:
1821 this->sized_write_globals<64, true>(input_objects, sympool,
1830 // Write out the global symbols.
1832 template<int size, bool big_endian>
1834 Symbol_table::sized_write_globals(const Input_objects* input_objects,
1835 const Stringpool* sympool,
1836 const Stringpool* dynpool,
1837 Output_file* of) const
1839 const Target& target = parameters->target();
1841 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1843 const unsigned int output_count = this->output_count_;
1844 const section_size_type oview_size = output_count * sym_size;
1845 const unsigned int first_global_index = this->first_global_index_;
1846 unsigned char* psyms;
1847 if (this->offset_ == 0 || output_count == 0)
1850 psyms = of->get_output_view(this->offset_, oview_size);
1852 const unsigned int dynamic_count = this->dynamic_count_;
1853 const section_size_type dynamic_size = dynamic_count * sym_size;
1854 const unsigned int first_dynamic_global_index =
1855 this->first_dynamic_global_index_;
1856 unsigned char* dynamic_view;
1857 if (this->dynamic_offset_ == 0 || dynamic_count == 0)
1858 dynamic_view = NULL;
1860 dynamic_view = of->get_output_view(this->dynamic_offset_, dynamic_size);
1862 for (Symbol_table_type::const_iterator p = this->table_.begin();
1863 p != this->table_.end();
1866 Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second);
1868 // Possibly warn about unresolved symbols in shared libraries.
1869 this->warn_about_undefined_dynobj_symbol(input_objects, sym);
1871 unsigned int sym_index = sym->symtab_index();
1872 unsigned int dynsym_index;
1873 if (dynamic_view == NULL)
1876 dynsym_index = sym->dynsym_index();
1878 if (sym_index == -1U && dynsym_index == -1U)
1880 // This symbol is not included in the output file.
1885 typename elfcpp::Elf_types<size>::Elf_Addr sym_value = sym->value();
1886 typename elfcpp::Elf_types<size>::Elf_Addr dynsym_value = sym_value;
1887 switch (sym->source())
1889 case Symbol::FROM_OBJECT:
1891 unsigned int in_shndx = sym->shndx();
1893 // FIXME: We need some target specific support here.
1894 if (in_shndx >= elfcpp::SHN_LORESERVE
1895 && in_shndx != elfcpp::SHN_ABS
1896 && in_shndx != elfcpp::SHN_COMMON)
1898 gold_error(_("%s: unsupported symbol section 0x%x"),
1899 sym->demangled_name().c_str(), in_shndx);
1904 Object* symobj = sym->object();
1905 if (symobj->is_dynamic())
1907 if (sym->needs_dynsym_value())
1908 dynsym_value = target.dynsym_value(sym);
1909 shndx = elfcpp::SHN_UNDEF;
1911 else if (in_shndx == elfcpp::SHN_UNDEF
1912 || in_shndx == elfcpp::SHN_ABS
1913 || in_shndx == elfcpp::SHN_COMMON)
1917 Relobj* relobj = static_cast<Relobj*>(symobj);
1918 section_offset_type secoff;
1919 Output_section* os = relobj->output_section(in_shndx,
1921 gold_assert(os != NULL);
1922 shndx = os->out_shndx();
1924 // In object files symbol values are section
1926 if (parameters->options().relocatable())
1927 sym_value -= os->address();
1933 case Symbol::IN_OUTPUT_DATA:
1934 shndx = sym->output_data()->out_shndx();
1937 case Symbol::IN_OUTPUT_SEGMENT:
1938 shndx = elfcpp::SHN_ABS;
1941 case Symbol::CONSTANT:
1942 shndx = elfcpp::SHN_ABS;
1949 if (sym_index != -1U)
1951 sym_index -= first_global_index;
1952 gold_assert(sym_index < output_count);
1953 unsigned char* ps = psyms + (sym_index * sym_size);
1954 this->sized_write_symbol<size, big_endian>(sym, sym_value, shndx,
1958 if (dynsym_index != -1U)
1960 dynsym_index -= first_dynamic_global_index;
1961 gold_assert(dynsym_index < dynamic_count);
1962 unsigned char* pd = dynamic_view + (dynsym_index * sym_size);
1963 this->sized_write_symbol<size, big_endian>(sym, dynsym_value, shndx,
1968 of->write_output_view(this->offset_, oview_size, psyms);
1969 if (dynamic_view != NULL)
1970 of->write_output_view(this->dynamic_offset_, dynamic_size, dynamic_view);
1973 // Write out the symbol SYM, in section SHNDX, to P. POOL is the
1974 // strtab holding the name.
1976 template<int size, bool big_endian>
1978 Symbol_table::sized_write_symbol(
1979 Sized_symbol<size>* sym,
1980 typename elfcpp::Elf_types<size>::Elf_Addr value,
1982 const Stringpool* pool,
1983 unsigned char* p) const
1985 elfcpp::Sym_write<size, big_endian> osym(p);
1986 osym.put_st_name(pool->get_offset(sym->name()));
1987 osym.put_st_value(value);
1988 osym.put_st_size(sym->symsize());
1989 // A version script may have overridden the default binding.
1990 if (sym->is_forced_local())
1991 osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL, sym->type()));
1993 osym.put_st_info(elfcpp::elf_st_info(sym->binding(), sym->type()));
1994 osym.put_st_other(elfcpp::elf_st_other(sym->visibility(), sym->nonvis()));
1995 osym.put_st_shndx(shndx);
1998 // Check for unresolved symbols in shared libraries. This is
1999 // controlled by the --allow-shlib-undefined option.
2001 // We only warn about libraries for which we have seen all the
2002 // DT_NEEDED entries. We don't try to track down DT_NEEDED entries
2003 // which were not seen in this link. If we didn't see a DT_NEEDED
2004 // entry, we aren't going to be able to reliably report whether the
2005 // symbol is undefined.
2007 // We also don't warn about libraries found in the system library
2008 // directory (the directory were we find libc.so); we assume that
2009 // those libraries are OK. This heuristic avoids problems in
2010 // GNU/Linux, in which -ldl can have undefined references satisfied by
2014 Symbol_table::warn_about_undefined_dynobj_symbol(
2015 const Input_objects* input_objects,
2018 if (sym->source() == Symbol::FROM_OBJECT
2019 && sym->object()->is_dynamic()
2020 && sym->shndx() == elfcpp::SHN_UNDEF
2021 && sym->binding() != elfcpp::STB_WEAK
2022 && !parameters->options().allow_shlib_undefined()
2023 && !parameters->target().is_defined_by_abi(sym)
2024 && !input_objects->found_in_system_library_directory(sym->object()))
2026 // A very ugly cast.
2027 Dynobj* dynobj = static_cast<Dynobj*>(sym->object());
2028 if (!dynobj->has_unknown_needed_entries())
2029 gold_error(_("%s: undefined reference to '%s'"),
2030 sym->object()->name().c_str(),
2031 sym->demangled_name().c_str());
2035 // Write out a section symbol. Return the update offset.
2038 Symbol_table::write_section_symbol(const Output_section *os,
2042 switch (parameters->size_and_endianness())
2044 #ifdef HAVE_TARGET_32_LITTLE
2045 case Parameters::TARGET_32_LITTLE:
2046 this->sized_write_section_symbol<32, false>(os, of, offset);
2049 #ifdef HAVE_TARGET_32_BIG
2050 case Parameters::TARGET_32_BIG:
2051 this->sized_write_section_symbol<32, true>(os, of, offset);
2054 #ifdef HAVE_TARGET_64_LITTLE
2055 case Parameters::TARGET_64_LITTLE:
2056 this->sized_write_section_symbol<64, false>(os, of, offset);
2059 #ifdef HAVE_TARGET_64_BIG
2060 case Parameters::TARGET_64_BIG:
2061 this->sized_write_section_symbol<64, true>(os, of, offset);
2069 // Write out a section symbol, specialized for size and endianness.
2071 template<int size, bool big_endian>
2073 Symbol_table::sized_write_section_symbol(const Output_section* os,
2077 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2079 unsigned char* pov = of->get_output_view(offset, sym_size);
2081 elfcpp::Sym_write<size, big_endian> osym(pov);
2082 osym.put_st_name(0);
2083 osym.put_st_value(os->address());
2084 osym.put_st_size(0);
2085 osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL,
2086 elfcpp::STT_SECTION));
2087 osym.put_st_other(elfcpp::elf_st_other(elfcpp::STV_DEFAULT, 0));
2088 osym.put_st_shndx(os->out_shndx());
2090 of->write_output_view(offset, sym_size, pov);
2093 // Print statistical information to stderr. This is used for --stats.
2096 Symbol_table::print_stats() const
2098 #if defined(HAVE_TR1_UNORDERED_MAP) || defined(HAVE_EXT_HASH_MAP)
2099 fprintf(stderr, _("%s: symbol table entries: %zu; buckets: %zu\n"),
2100 program_name, this->table_.size(), this->table_.bucket_count());
2102 fprintf(stderr, _("%s: symbol table entries: %zu\n"),
2103 program_name, this->table_.size());
2105 this->namepool_.print_stats("symbol table stringpool");
2108 // We check for ODR violations by looking for symbols with the same
2109 // name for which the debugging information reports that they were
2110 // defined in different source locations. When comparing the source
2111 // location, we consider instances with the same base filename and
2112 // line number to be the same. This is because different object
2113 // files/shared libraries can include the same header file using
2114 // different paths, and we don't want to report an ODR violation in
2117 // This struct is used to compare line information, as returned by
2118 // Dwarf_line_info::one_addr2line. It implements a < comparison
2119 // operator used with std::set.
2121 struct Odr_violation_compare
2124 operator()(const std::string& s1, const std::string& s2) const
2126 std::string::size_type pos1 = s1.rfind('/');
2127 std::string::size_type pos2 = s2.rfind('/');
2128 if (pos1 == std::string::npos
2129 || pos2 == std::string::npos)
2131 return s1.compare(pos1, std::string::npos,
2132 s2, pos2, std::string::npos) < 0;
2136 // Check candidate_odr_violations_ to find symbols with the same name
2137 // but apparently different definitions (different source-file/line-no).
2140 Symbol_table::detect_odr_violations(const Task* task,
2141 const char* output_file_name) const
2143 for (Odr_map::const_iterator it = candidate_odr_violations_.begin();
2144 it != candidate_odr_violations_.end();
2147 const char* symbol_name = it->first;
2148 // We use a sorted set so the output is deterministic.
2149 std::set<std::string, Odr_violation_compare> line_nums;
2151 for (Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
2152 locs = it->second.begin();
2153 locs != it->second.end();
2156 // We need to lock the object in order to read it. This
2157 // means that we have to run in a singleton Task. If we
2158 // want to run this in a general Task for better
2159 // performance, we will need one Task for object, plus
2160 // appropriate locking to ensure that we don't conflict with
2161 // other uses of the object.
2162 Task_lock_obj<Object> tl(task, locs->object);
2163 std::string lineno = Dwarf_line_info::one_addr2line(
2164 locs->object, locs->shndx, locs->offset);
2165 if (!lineno.empty())
2166 line_nums.insert(lineno);
2169 if (line_nums.size() > 1)
2171 gold_warning(_("while linking %s: symbol '%s' defined in multiple "
2172 "places (possible ODR violation):"),
2173 output_file_name, demangle(symbol_name).c_str());
2174 for (std::set<std::string>::const_iterator it2 = line_nums.begin();
2175 it2 != line_nums.end();
2177 fprintf(stderr, " %s\n", it2->c_str());
2182 // Warnings functions.
2184 // Add a new warning.
2187 Warnings::add_warning(Symbol_table* symtab, const char* name, Object* obj,
2188 const std::string& warning)
2190 name = symtab->canonicalize_name(name);
2191 this->warnings_[name].set(obj, warning);
2194 // Look through the warnings and mark the symbols for which we should
2195 // warn. This is called during Layout::finalize when we know the
2196 // sources for all the symbols.
2199 Warnings::note_warnings(Symbol_table* symtab)
2201 for (Warning_table::iterator p = this->warnings_.begin();
2202 p != this->warnings_.end();
2205 Symbol* sym = symtab->lookup(p->first, NULL);
2207 && sym->source() == Symbol::FROM_OBJECT
2208 && sym->object() == p->second.object)
2209 sym->set_has_warning();
2213 // Issue a warning. This is called when we see a relocation against a
2214 // symbol for which has a warning.
2216 template<int size, bool big_endian>
2218 Warnings::issue_warning(const Symbol* sym,
2219 const Relocate_info<size, big_endian>* relinfo,
2220 size_t relnum, off_t reloffset) const
2222 gold_assert(sym->has_warning());
2223 Warning_table::const_iterator p = this->warnings_.find(sym->name());
2224 gold_assert(p != this->warnings_.end());
2225 gold_warning_at_location(relinfo, relnum, reloffset,
2226 "%s", p->second.text.c_str());
2229 // Instantiate the templates we need. We could use the configure
2230 // script to restrict this to only the ones needed for implemented
2233 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
2236 Sized_symbol<32>::allocate_common(Output_data*, Value_type);
2239 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
2242 Sized_symbol<64>::allocate_common(Output_data*, Value_type);
2245 #ifdef HAVE_TARGET_32_LITTLE
2248 Symbol_table::add_from_relobj<32, false>(
2249 Sized_relobj<32, false>* relobj,
2250 const unsigned char* syms,
2252 const char* sym_names,
2253 size_t sym_name_size,
2254 Sized_relobj<32, true>::Symbols* sympointers);
2257 #ifdef HAVE_TARGET_32_BIG
2260 Symbol_table::add_from_relobj<32, true>(
2261 Sized_relobj<32, true>* relobj,
2262 const unsigned char* syms,
2264 const char* sym_names,
2265 size_t sym_name_size,
2266 Sized_relobj<32, false>::Symbols* sympointers);
2269 #ifdef HAVE_TARGET_64_LITTLE
2272 Symbol_table::add_from_relobj<64, false>(
2273 Sized_relobj<64, false>* relobj,
2274 const unsigned char* syms,
2276 const char* sym_names,
2277 size_t sym_name_size,
2278 Sized_relobj<64, true>::Symbols* sympointers);
2281 #ifdef HAVE_TARGET_64_BIG
2284 Symbol_table::add_from_relobj<64, true>(
2285 Sized_relobj<64, true>* relobj,
2286 const unsigned char* syms,
2288 const char* sym_names,
2289 size_t sym_name_size,
2290 Sized_relobj<64, false>::Symbols* sympointers);
2293 #ifdef HAVE_TARGET_32_LITTLE
2296 Symbol_table::add_from_dynobj<32, false>(
2297 Sized_dynobj<32, false>* dynobj,
2298 const unsigned char* syms,
2300 const char* sym_names,
2301 size_t sym_name_size,
2302 const unsigned char* versym,
2304 const std::vector<const char*>* version_map);
2307 #ifdef HAVE_TARGET_32_BIG
2310 Symbol_table::add_from_dynobj<32, true>(
2311 Sized_dynobj<32, true>* dynobj,
2312 const unsigned char* syms,
2314 const char* sym_names,
2315 size_t sym_name_size,
2316 const unsigned char* versym,
2318 const std::vector<const char*>* version_map);
2321 #ifdef HAVE_TARGET_64_LITTLE
2324 Symbol_table::add_from_dynobj<64, false>(
2325 Sized_dynobj<64, false>* dynobj,
2326 const unsigned char* syms,
2328 const char* sym_names,
2329 size_t sym_name_size,
2330 const unsigned char* versym,
2332 const std::vector<const char*>* version_map);
2335 #ifdef HAVE_TARGET_64_BIG
2338 Symbol_table::add_from_dynobj<64, true>(
2339 Sized_dynobj<64, true>* dynobj,
2340 const unsigned char* syms,
2342 const char* sym_names,
2343 size_t sym_name_size,
2344 const unsigned char* versym,
2346 const std::vector<const char*>* version_map);
2349 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
2352 Symbol_table::define_with_copy_reloc<32>(
2353 Sized_symbol<32>* sym,
2355 elfcpp::Elf_types<32>::Elf_Addr value);
2358 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
2361 Symbol_table::define_with_copy_reloc<64>(
2362 Sized_symbol<64>* sym,
2364 elfcpp::Elf_types<64>::Elf_Addr value);
2367 #ifdef HAVE_TARGET_32_LITTLE
2370 Warnings::issue_warning<32, false>(const Symbol* sym,
2371 const Relocate_info<32, false>* relinfo,
2372 size_t relnum, off_t reloffset) const;
2375 #ifdef HAVE_TARGET_32_BIG
2378 Warnings::issue_warning<32, true>(const Symbol* sym,
2379 const Relocate_info<32, true>* relinfo,
2380 size_t relnum, off_t reloffset) const;
2383 #ifdef HAVE_TARGET_64_LITTLE
2386 Warnings::issue_warning<64, false>(const Symbol* sym,
2387 const Relocate_info<64, false>* relinfo,
2388 size_t relnum, off_t reloffset) const;
2391 #ifdef HAVE_TARGET_64_BIG
2394 Warnings::issue_warning<64, true>(const Symbol* sym,
2395 const Relocate_info<64, true>* relinfo,
2396 size_t relnum, off_t reloffset) const;
2399 } // End namespace gold.