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[binutils.git] / gold / symtab.cc
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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.
23 #include "gold.h"
25 #include <cstring>
26 #include <stdint.h>
27 #include <algorithm>
28 #include <set>
29 #include <string>
30 #include <utility>
31 #include "demangle.h"
33 #include "object.h"
34 #include "dwarf_reader.h"
35 #include "dynobj.h"
36 #include "output.h"
37 #include "target.h"
38 #include "workqueue.h"
39 #include "symtab.h"
41 namespace gold
44 // Class Symbol.
46 // Initialize fields in Symbol. This initializes everything except u_
47 // and source_.
49 void
50 Symbol::init_fields(const char* name, const char* version,
51 elfcpp::STT type, elfcpp::STB binding,
52 elfcpp::STV visibility, unsigned char nonvis)
54 this->name_ = name;
55 this->version_ = version;
56 this->symtab_index_ = 0;
57 this->dynsym_index_ = 0;
58 this->got_offsets_.init();
59 this->plt_offset_ = 0;
60 this->type_ = type;
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;
75 this->is_ordinary_shndx_ = false;
78 // Return the demangled version of the symbol's name, but only
79 // if the --demangle flag was set.
81 static std::string
82 demangle(const char* name)
84 if (!parameters->options().do_demangle())
85 return name;
87 // cplus_demangle allocates memory for the result it returns,
88 // and returns NULL if the name is already demangled.
89 char* demangled_name = cplus_demangle(name, DMGL_ANSI | DMGL_PARAMS);
90 if (demangled_name == NULL)
91 return name;
93 std::string retval(demangled_name);
94 free(demangled_name);
95 return retval;
98 std::string
99 Symbol::demangled_name() const
101 return demangle(this->name());
104 // Initialize the fields in the base class Symbol for SYM in OBJECT.
106 template<int size, bool big_endian>
107 void
108 Symbol::init_base_object(const char* name, const char* version, Object* object,
109 const elfcpp::Sym<size, big_endian>& sym,
110 unsigned int st_shndx, bool is_ordinary)
112 this->init_fields(name, version, sym.get_st_type(), sym.get_st_bind(),
113 sym.get_st_visibility(), sym.get_st_nonvis());
114 this->u_.from_object.object = object;
115 this->u_.from_object.shndx = st_shndx;
116 this->is_ordinary_shndx_ = is_ordinary;
117 this->source_ = FROM_OBJECT;
118 this->in_reg_ = !object->is_dynamic();
119 this->in_dyn_ = object->is_dynamic();
122 // Initialize the fields in the base class Symbol for a symbol defined
123 // in an Output_data.
125 void
126 Symbol::init_base_output_data(const char* name, const char* version,
127 Output_data* od, elfcpp::STT type,
128 elfcpp::STB binding, elfcpp::STV visibility,
129 unsigned char nonvis, bool offset_is_from_end)
131 this->init_fields(name, version, type, binding, visibility, nonvis);
132 this->u_.in_output_data.output_data = od;
133 this->u_.in_output_data.offset_is_from_end = offset_is_from_end;
134 this->source_ = IN_OUTPUT_DATA;
135 this->in_reg_ = true;
138 // Initialize the fields in the base class Symbol for a symbol defined
139 // in an Output_segment.
141 void
142 Symbol::init_base_output_segment(const char* name, const char* version,
143 Output_segment* os, elfcpp::STT type,
144 elfcpp::STB binding, elfcpp::STV visibility,
145 unsigned char nonvis,
146 Segment_offset_base offset_base)
148 this->init_fields(name, version, type, binding, visibility, nonvis);
149 this->u_.in_output_segment.output_segment = os;
150 this->u_.in_output_segment.offset_base = offset_base;
151 this->source_ = IN_OUTPUT_SEGMENT;
152 this->in_reg_ = true;
155 // Initialize the fields in the base class Symbol for a symbol defined
156 // as a constant.
158 void
159 Symbol::init_base_constant(const char* name, const char* version,
160 elfcpp::STT type, elfcpp::STB binding,
161 elfcpp::STV visibility, unsigned char nonvis)
163 this->init_fields(name, version, type, binding, visibility, nonvis);
164 this->source_ = IS_CONSTANT;
165 this->in_reg_ = true;
168 // Initialize the fields in the base class Symbol for an undefined
169 // symbol.
171 void
172 Symbol::init_base_undefined(const char* name, const char* version,
173 elfcpp::STT type, elfcpp::STB binding,
174 elfcpp::STV visibility, unsigned char nonvis)
176 this->init_fields(name, version, type, binding, visibility, nonvis);
177 this->source_ = IS_UNDEFINED;
178 this->in_reg_ = true;
181 // Allocate a common symbol in the base.
183 void
184 Symbol::allocate_base_common(Output_data* od)
186 gold_assert(this->is_common());
187 this->source_ = IN_OUTPUT_DATA;
188 this->u_.in_output_data.output_data = od;
189 this->u_.in_output_data.offset_is_from_end = false;
192 // Initialize the fields in Sized_symbol for SYM in OBJECT.
194 template<int size>
195 template<bool big_endian>
196 void
197 Sized_symbol<size>::init_object(const char* name, const char* version,
198 Object* object,
199 const elfcpp::Sym<size, big_endian>& sym,
200 unsigned int st_shndx, bool is_ordinary)
202 this->init_base_object(name, version, object, sym, st_shndx, is_ordinary);
203 this->value_ = sym.get_st_value();
204 this->symsize_ = sym.get_st_size();
207 // Initialize the fields in Sized_symbol for a symbol defined in an
208 // Output_data.
210 template<int size>
211 void
212 Sized_symbol<size>::init_output_data(const char* name, const char* version,
213 Output_data* od, Value_type value,
214 Size_type symsize, elfcpp::STT type,
215 elfcpp::STB binding,
216 elfcpp::STV visibility,
217 unsigned char nonvis,
218 bool offset_is_from_end)
220 this->init_base_output_data(name, version, od, type, binding, visibility,
221 nonvis, offset_is_from_end);
222 this->value_ = value;
223 this->symsize_ = symsize;
226 // Initialize the fields in Sized_symbol for a symbol defined in an
227 // Output_segment.
229 template<int size>
230 void
231 Sized_symbol<size>::init_output_segment(const char* name, const char* version,
232 Output_segment* os, Value_type value,
233 Size_type symsize, elfcpp::STT type,
234 elfcpp::STB binding,
235 elfcpp::STV visibility,
236 unsigned char nonvis,
237 Segment_offset_base offset_base)
239 this->init_base_output_segment(name, version, os, type, binding, visibility,
240 nonvis, offset_base);
241 this->value_ = value;
242 this->symsize_ = symsize;
245 // Initialize the fields in Sized_symbol for a symbol defined as a
246 // constant.
248 template<int size>
249 void
250 Sized_symbol<size>::init_constant(const char* name, const char* version,
251 Value_type value, Size_type symsize,
252 elfcpp::STT type, elfcpp::STB binding,
253 elfcpp::STV visibility, unsigned char nonvis)
255 this->init_base_constant(name, version, type, binding, visibility, nonvis);
256 this->value_ = value;
257 this->symsize_ = symsize;
260 // Initialize the fields in Sized_symbol for an undefined symbol.
262 template<int size>
263 void
264 Sized_symbol<size>::init_undefined(const char* name, const char* version,
265 elfcpp::STT type, elfcpp::STB binding,
266 elfcpp::STV visibility, unsigned char nonvis)
268 this->init_base_undefined(name, version, type, binding, visibility, nonvis);
269 this->value_ = 0;
270 this->symsize_ = 0;
273 // Allocate a common symbol.
275 template<int size>
276 void
277 Sized_symbol<size>::allocate_common(Output_data* od, Value_type value)
279 this->allocate_base_common(od);
280 this->value_ = value;
283 // Return true if this symbol should be added to the dynamic symbol
284 // table.
286 inline bool
287 Symbol::should_add_dynsym_entry() const
289 // If the symbol is used by a dynamic relocation, we need to add it.
290 if (this->needs_dynsym_entry())
291 return true;
293 // If the symbol was forced local in a version script, do not add it.
294 if (this->is_forced_local())
295 return false;
297 // If exporting all symbols or building a shared library,
298 // and the symbol is defined in a regular object and is
299 // externally visible, we need to add it.
300 if ((parameters->options().export_dynamic() || parameters->options().shared())
301 && !this->is_from_dynobj()
302 && this->is_externally_visible())
303 return true;
305 return false;
308 // Return true if the final value of this symbol is known at link
309 // time.
311 bool
312 Symbol::final_value_is_known() const
314 // If we are not generating an executable, then no final values are
315 // known, since they will change at runtime.
316 if (parameters->options().shared() || parameters->options().relocatable())
317 return false;
319 // If the symbol is not from an object file, and is not undefined,
320 // then it is defined, and known.
321 if (this->source_ != FROM_OBJECT)
323 if (this->source_ != IS_UNDEFINED)
324 return true;
326 else
328 // If the symbol is from a dynamic object, then the final value
329 // is not known.
330 if (this->object()->is_dynamic())
331 return false;
333 // If the symbol is not undefined (it is defined or common),
334 // then the final value is known.
335 if (!this->is_undefined())
336 return true;
339 // If the symbol is undefined, then whether the final value is known
340 // depends on whether we are doing a static link. If we are doing a
341 // dynamic link, then the final value could be filled in at runtime.
342 // This could reasonably be the case for a weak undefined symbol.
343 return parameters->doing_static_link();
346 // Return the output section where this symbol is defined.
348 Output_section*
349 Symbol::output_section() const
351 switch (this->source_)
353 case FROM_OBJECT:
355 unsigned int shndx = this->u_.from_object.shndx;
356 if (shndx != elfcpp::SHN_UNDEF && this->is_ordinary_shndx_)
358 gold_assert(!this->u_.from_object.object->is_dynamic());
359 Relobj* relobj = static_cast<Relobj*>(this->u_.from_object.object);
360 return relobj->output_section(shndx);
362 return NULL;
365 case IN_OUTPUT_DATA:
366 return this->u_.in_output_data.output_data->output_section();
368 case IN_OUTPUT_SEGMENT:
369 case IS_CONSTANT:
370 case IS_UNDEFINED:
371 return NULL;
373 default:
374 gold_unreachable();
378 // Set the symbol's output section. This is used for symbols defined
379 // in scripts. This should only be called after the symbol table has
380 // been finalized.
382 void
383 Symbol::set_output_section(Output_section* os)
385 switch (this->source_)
387 case FROM_OBJECT:
388 case IN_OUTPUT_DATA:
389 gold_assert(this->output_section() == os);
390 break;
391 case IS_CONSTANT:
392 this->source_ = IN_OUTPUT_DATA;
393 this->u_.in_output_data.output_data = os;
394 this->u_.in_output_data.offset_is_from_end = false;
395 break;
396 case IN_OUTPUT_SEGMENT:
397 case IS_UNDEFINED:
398 default:
399 gold_unreachable();
403 // Class Symbol_table.
405 Symbol_table::Symbol_table(unsigned int count,
406 const Version_script_info& version_script)
407 : saw_undefined_(0), offset_(0), table_(count), namepool_(),
408 forwarders_(), commons_(), tls_commons_(), forced_locals_(), warnings_(),
409 version_script_(version_script)
411 namepool_.reserve(count);
414 Symbol_table::~Symbol_table()
418 // The hash function. The key values are Stringpool keys.
420 inline size_t
421 Symbol_table::Symbol_table_hash::operator()(const Symbol_table_key& key) const
423 return key.first ^ key.second;
426 // The symbol table key equality function. This is called with
427 // Stringpool keys.
429 inline bool
430 Symbol_table::Symbol_table_eq::operator()(const Symbol_table_key& k1,
431 const Symbol_table_key& k2) const
433 return k1.first == k2.first && k1.second == k2.second;
436 // Make TO a symbol which forwards to FROM.
438 void
439 Symbol_table::make_forwarder(Symbol* from, Symbol* to)
441 gold_assert(from != to);
442 gold_assert(!from->is_forwarder() && !to->is_forwarder());
443 this->forwarders_[from] = to;
444 from->set_forwarder();
447 // Resolve the forwards from FROM, returning the real symbol.
449 Symbol*
450 Symbol_table::resolve_forwards(const Symbol* from) const
452 gold_assert(from->is_forwarder());
453 Unordered_map<const Symbol*, Symbol*>::const_iterator p =
454 this->forwarders_.find(from);
455 gold_assert(p != this->forwarders_.end());
456 return p->second;
459 // Look up a symbol by name.
461 Symbol*
462 Symbol_table::lookup(const char* name, const char* version) const
464 Stringpool::Key name_key;
465 name = this->namepool_.find(name, &name_key);
466 if (name == NULL)
467 return NULL;
469 Stringpool::Key version_key = 0;
470 if (version != NULL)
472 version = this->namepool_.find(version, &version_key);
473 if (version == NULL)
474 return NULL;
477 Symbol_table_key key(name_key, version_key);
478 Symbol_table::Symbol_table_type::const_iterator p = this->table_.find(key);
479 if (p == this->table_.end())
480 return NULL;
481 return p->second;
484 // Resolve a Symbol with another Symbol. This is only used in the
485 // unusual case where there are references to both an unversioned
486 // symbol and a symbol with a version, and we then discover that that
487 // version is the default version. Because this is unusual, we do
488 // this the slow way, by converting back to an ELF symbol.
490 template<int size, bool big_endian>
491 void
492 Symbol_table::resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from,
493 const char* version)
495 unsigned char buf[elfcpp::Elf_sizes<size>::sym_size];
496 elfcpp::Sym_write<size, big_endian> esym(buf);
497 // We don't bother to set the st_name or the st_shndx field.
498 esym.put_st_value(from->value());
499 esym.put_st_size(from->symsize());
500 esym.put_st_info(from->binding(), from->type());
501 esym.put_st_other(from->visibility(), from->nonvis());
502 bool is_ordinary;
503 unsigned int shndx = from->shndx(&is_ordinary);
504 this->resolve(to, esym.sym(), shndx, is_ordinary, shndx, from->object(),
505 version);
506 if (from->in_reg())
507 to->set_in_reg();
508 if (from->in_dyn())
509 to->set_in_dyn();
512 // Record that a symbol is forced to be local by a version script.
514 void
515 Symbol_table::force_local(Symbol* sym)
517 if (!sym->is_defined() && !sym->is_common())
518 return;
519 if (sym->is_forced_local())
521 // We already got this one.
522 return;
524 sym->set_is_forced_local();
525 this->forced_locals_.push_back(sym);
528 // Adjust NAME for wrapping, and update *NAME_KEY if necessary. This
529 // is only called for undefined symbols, when at least one --wrap
530 // option was used.
532 const char*
533 Symbol_table::wrap_symbol(Object* object, const char* name,
534 Stringpool::Key* name_key)
536 // For some targets, we need to ignore a specific character when
537 // wrapping, and add it back later.
538 char prefix = '\0';
539 if (name[0] == object->target()->wrap_char())
541 prefix = name[0];
542 ++name;
545 if (parameters->options().is_wrap(name))
547 // Turn NAME into __wrap_NAME.
548 std::string s;
549 if (prefix != '\0')
550 s += prefix;
551 s += "__wrap_";
552 s += name;
554 // This will give us both the old and new name in NAMEPOOL_, but
555 // that is OK. Only the versions we need will wind up in the
556 // real string table in the output file.
557 return this->namepool_.add(s.c_str(), true, name_key);
560 const char* const real_prefix = "__real_";
561 const size_t real_prefix_length = strlen(real_prefix);
562 if (strncmp(name, real_prefix, real_prefix_length) == 0
563 && parameters->options().is_wrap(name + real_prefix_length))
565 // Turn __real_NAME into NAME.
566 std::string s;
567 if (prefix != '\0')
568 s += prefix;
569 s += name + real_prefix_length;
570 return this->namepool_.add(s.c_str(), true, name_key);
573 return name;
576 // Add one symbol from OBJECT to the symbol table. NAME is symbol
577 // name and VERSION is the version; both are canonicalized. DEF is
578 // whether this is the default version. ST_SHNDX is the symbol's
579 // section index; IS_ORDINARY is whether this is a normal section
580 // rather than a special code.
582 // If DEF is true, then this is the definition of a default version of
583 // a symbol. That means that any lookup of NAME/NULL and any lookup
584 // of NAME/VERSION should always return the same symbol. This is
585 // obvious for references, but in particular we want to do this for
586 // definitions: overriding NAME/NULL should also override
587 // NAME/VERSION. If we don't do that, it would be very hard to
588 // override functions in a shared library which uses versioning.
590 // We implement this by simply making both entries in the hash table
591 // point to the same Symbol structure. That is easy enough if this is
592 // the first time we see NAME/NULL or NAME/VERSION, but it is possible
593 // that we have seen both already, in which case they will both have
594 // independent entries in the symbol table. We can't simply change
595 // the symbol table entry, because we have pointers to the entries
596 // attached to the object files. So we mark the entry attached to the
597 // object file as a forwarder, and record it in the forwarders_ map.
598 // Note that entries in the hash table will never be marked as
599 // forwarders.
601 // ORIG_ST_SHNDX and ST_SHNDX are almost always the same.
602 // ORIG_ST_SHNDX is the section index in the input file, or SHN_UNDEF
603 // for a special section code. ST_SHNDX may be modified if the symbol
604 // is defined in a section being discarded.
606 template<int size, bool big_endian>
607 Sized_symbol<size>*
608 Symbol_table::add_from_object(Object* object,
609 const char *name,
610 Stringpool::Key name_key,
611 const char *version,
612 Stringpool::Key version_key,
613 bool def,
614 const elfcpp::Sym<size, big_endian>& sym,
615 unsigned int st_shndx,
616 bool is_ordinary,
617 unsigned int orig_st_shndx)
619 // Print a message if this symbol is being traced.
620 if (parameters->options().is_trace_symbol(name))
622 if (orig_st_shndx == elfcpp::SHN_UNDEF)
623 gold_info(_("%s: reference to %s"), object->name().c_str(), name);
624 else
625 gold_info(_("%s: definition of %s"), object->name().c_str(), name);
628 // For an undefined symbol, we may need to adjust the name using
629 // --wrap.
630 if (orig_st_shndx == elfcpp::SHN_UNDEF
631 && parameters->options().any_wrap())
633 const char* wrap_name = this->wrap_symbol(object, name, &name_key);
634 if (wrap_name != name)
636 // If we see a reference to malloc with version GLIBC_2.0,
637 // and we turn it into a reference to __wrap_malloc, then we
638 // discard the version number. Otherwise the user would be
639 // required to specify the correct version for
640 // __wrap_malloc.
641 version = NULL;
642 version_key = 0;
643 name = wrap_name;
647 Symbol* const snull = NULL;
648 std::pair<typename Symbol_table_type::iterator, bool> ins =
649 this->table_.insert(std::make_pair(std::make_pair(name_key, version_key),
650 snull));
652 std::pair<typename Symbol_table_type::iterator, bool> insdef =
653 std::make_pair(this->table_.end(), false);
654 if (def)
656 const Stringpool::Key vnull_key = 0;
657 insdef = this->table_.insert(std::make_pair(std::make_pair(name_key,
658 vnull_key),
659 snull));
662 // ins.first: an iterator, which is a pointer to a pair.
663 // ins.first->first: the key (a pair of name and version).
664 // ins.first->second: the value (Symbol*).
665 // ins.second: true if new entry was inserted, false if not.
667 Sized_symbol<size>* ret;
668 bool was_undefined;
669 bool was_common;
670 if (!ins.second)
672 // We already have an entry for NAME/VERSION.
673 ret = this->get_sized_symbol<size>(ins.first->second);
674 gold_assert(ret != NULL);
676 was_undefined = ret->is_undefined();
677 was_common = ret->is_common();
679 this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
680 version);
682 if (def)
684 if (insdef.second)
686 // This is the first time we have seen NAME/NULL. Make
687 // NAME/NULL point to NAME/VERSION.
688 insdef.first->second = ret;
690 else if (insdef.first->second != ret)
692 // This is the unfortunate case where we already have
693 // entries for both NAME/VERSION and NAME/NULL. We now
694 // see a symbol NAME/VERSION where VERSION is the
695 // default version. We have already resolved this new
696 // symbol with the existing NAME/VERSION symbol.
698 // It's possible that NAME/NULL and NAME/VERSION are
699 // both defined in regular objects. This can only
700 // happen if one object file defines foo and another
701 // defines foo@@ver. This is somewhat obscure, but we
702 // call it a multiple definition error.
704 // It's possible that NAME/NULL actually has a version,
705 // in which case it won't be the same as VERSION. This
706 // happens with ver_test_7.so in the testsuite for the
707 // symbol t2_2. We see t2_2@@VER2, so we define both
708 // t2_2/VER2 and t2_2/NULL. We then see an unadorned
709 // t2_2 in an object file and give it version VER1 from
710 // the version script. This looks like a default
711 // definition for VER1, so it looks like we should merge
712 // t2_2/NULL with t2_2/VER1. That doesn't make sense,
713 // but it's not obvious that this is an error, either.
714 // So we just punt.
716 // If one of the symbols has non-default visibility, and
717 // the other is defined in a shared object, then they
718 // are different symbols.
720 // Otherwise, we just resolve the symbols as though they
721 // were the same.
723 if (insdef.first->second->version() != NULL)
725 gold_assert(insdef.first->second->version() != version);
726 def = false;
728 else if (ret->visibility() != elfcpp::STV_DEFAULT
729 && insdef.first->second->is_from_dynobj())
730 def = false;
731 else if (insdef.first->second->visibility() != elfcpp::STV_DEFAULT
732 && ret->is_from_dynobj())
733 def = false;
734 else
736 const Sized_symbol<size>* sym2;
737 sym2 = this->get_sized_symbol<size>(insdef.first->second);
738 Symbol_table::resolve<size, big_endian>(ret, sym2, version);
739 this->make_forwarder(insdef.first->second, ret);
740 insdef.first->second = ret;
743 else
744 def = false;
747 else
749 // This is the first time we have seen NAME/VERSION.
750 gold_assert(ins.first->second == NULL);
752 if (def && !insdef.second)
754 // We already have an entry for NAME/NULL. If we override
755 // it, then change it to NAME/VERSION.
756 ret = this->get_sized_symbol<size>(insdef.first->second);
758 was_undefined = ret->is_undefined();
759 was_common = ret->is_common();
761 this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object,
762 version);
763 ins.first->second = ret;
765 else
767 was_undefined = false;
768 was_common = false;
770 Sized_target<size, big_endian>* target =
771 object->sized_target<size, big_endian>();
772 if (!target->has_make_symbol())
773 ret = new Sized_symbol<size>();
774 else
776 ret = target->make_symbol();
777 if (ret == NULL)
779 // This means that we don't want a symbol table
780 // entry after all.
781 if (!def)
782 this->table_.erase(ins.first);
783 else
785 this->table_.erase(insdef.first);
786 // Inserting insdef invalidated ins.
787 this->table_.erase(std::make_pair(name_key,
788 version_key));
790 return NULL;
794 ret->init_object(name, version, object, sym, st_shndx, is_ordinary);
796 ins.first->second = ret;
797 if (def)
799 // This is the first time we have seen NAME/NULL. Point
800 // it at the new entry for NAME/VERSION.
801 gold_assert(insdef.second);
802 insdef.first->second = ret;
807 // Record every time we see a new undefined symbol, to speed up
808 // archive groups.
809 if (!was_undefined && ret->is_undefined())
810 ++this->saw_undefined_;
812 // Keep track of common symbols, to speed up common symbol
813 // allocation.
814 if (!was_common && ret->is_common())
816 if (ret->type() != elfcpp::STT_TLS)
817 this->commons_.push_back(ret);
818 else
819 this->tls_commons_.push_back(ret);
822 if (def)
823 ret->set_is_default();
824 return ret;
827 // Add all the symbols in a relocatable object to the hash table.
829 template<int size, bool big_endian>
830 void
831 Symbol_table::add_from_relobj(
832 Sized_relobj<size, big_endian>* relobj,
833 const unsigned char* syms,
834 size_t count,
835 size_t symndx_offset,
836 const char* sym_names,
837 size_t sym_name_size,
838 typename Sized_relobj<size, big_endian>::Symbols* sympointers)
840 gold_assert(size == relobj->target()->get_size());
841 gold_assert(size == parameters->target().get_size());
843 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
845 const bool just_symbols = relobj->just_symbols();
847 const unsigned char* p = syms;
848 for (size_t i = 0; i < count; ++i, p += sym_size)
850 elfcpp::Sym<size, big_endian> sym(p);
852 unsigned int st_name = sym.get_st_name();
853 if (st_name >= sym_name_size)
855 relobj->error(_("bad global symbol name offset %u at %zu"),
856 st_name, i);
857 continue;
860 const char* name = sym_names + st_name;
862 bool is_ordinary;
863 unsigned int st_shndx = relobj->adjust_sym_shndx(i + symndx_offset,
864 sym.get_st_shndx(),
865 &is_ordinary);
866 unsigned int orig_st_shndx = st_shndx;
867 if (!is_ordinary)
868 orig_st_shndx = elfcpp::SHN_UNDEF;
870 // A symbol defined in a section which we are not including must
871 // be treated as an undefined symbol.
872 if (st_shndx != elfcpp::SHN_UNDEF
873 && is_ordinary
874 && !relobj->is_section_included(st_shndx))
875 st_shndx = elfcpp::SHN_UNDEF;
877 // In an object file, an '@' in the name separates the symbol
878 // name from the version name. If there are two '@' characters,
879 // this is the default version.
880 const char* ver = strchr(name, '@');
881 int namelen = 0;
882 // DEF: is the version default? LOCAL: is the symbol forced local?
883 bool def = false;
884 bool local = false;
886 if (ver != NULL)
888 // The symbol name is of the form foo@VERSION or foo@@VERSION
889 namelen = ver - name;
890 ++ver;
891 if (*ver == '@')
893 def = true;
894 ++ver;
897 // We don't want to assign a version to an undefined symbol,
898 // even if it is listed in the version script. FIXME: What
899 // about a common symbol?
900 else if (!version_script_.empty()
901 && st_shndx != elfcpp::SHN_UNDEF)
903 // The symbol name did not have a version, but
904 // the version script may assign a version anyway.
905 namelen = strlen(name);
906 def = true;
907 // Check the global: entries from the version script.
908 const std::string& version =
909 version_script_.get_symbol_version(name);
910 if (!version.empty())
911 ver = version.c_str();
912 // Check the local: entries from the version script
913 if (version_script_.symbol_is_local(name))
914 local = true;
917 elfcpp::Sym<size, big_endian>* psym = &sym;
918 unsigned char symbuf[sym_size];
919 elfcpp::Sym<size, big_endian> sym2(symbuf);
920 if (just_symbols)
922 memcpy(symbuf, p, sym_size);
923 elfcpp::Sym_write<size, big_endian> sw(symbuf);
924 if (orig_st_shndx != elfcpp::SHN_UNDEF && is_ordinary)
926 // Symbol values in object files are section relative.
927 // This is normally what we want, but since here we are
928 // converting the symbol to absolute we need to add the
929 // section address. The section address in an object
930 // file is normally zero, but people can use a linker
931 // script to change it.
932 sw.put_st_value(sym.get_st_value()
933 + relobj->section_address(orig_st_shndx));
935 st_shndx = elfcpp::SHN_ABS;
936 is_ordinary = false;
937 psym = &sym2;
940 Sized_symbol<size>* res;
941 if (ver == NULL)
943 Stringpool::Key name_key;
944 name = this->namepool_.add(name, true, &name_key);
945 res = this->add_from_object(relobj, name, name_key, NULL, 0,
946 false, *psym, st_shndx, is_ordinary,
947 orig_st_shndx);
948 if (local)
949 this->force_local(res);
951 else
953 Stringpool::Key name_key;
954 name = this->namepool_.add_with_length(name, namelen, true,
955 &name_key);
956 Stringpool::Key ver_key;
957 ver = this->namepool_.add(ver, true, &ver_key);
959 res = this->add_from_object(relobj, name, name_key, ver, ver_key,
960 def, *psym, st_shndx, is_ordinary,
961 orig_st_shndx);
964 (*sympointers)[i] = res;
968 // Add all the symbols in a dynamic object to the hash table.
970 template<int size, bool big_endian>
971 void
972 Symbol_table::add_from_dynobj(
973 Sized_dynobj<size, big_endian>* dynobj,
974 const unsigned char* syms,
975 size_t count,
976 const char* sym_names,
977 size_t sym_name_size,
978 const unsigned char* versym,
979 size_t versym_size,
980 const std::vector<const char*>* version_map)
982 gold_assert(size == dynobj->target()->get_size());
983 gold_assert(size == parameters->target().get_size());
985 if (dynobj->just_symbols())
987 gold_error(_("--just-symbols does not make sense with a shared object"));
988 return;
991 if (versym != NULL && versym_size / 2 < count)
993 dynobj->error(_("too few symbol versions"));
994 return;
997 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
999 // We keep a list of all STT_OBJECT symbols, so that we can resolve
1000 // weak aliases. This is necessary because if the dynamic object
1001 // provides the same variable under two names, one of which is a
1002 // weak definition, and the regular object refers to the weak
1003 // definition, we have to put both the weak definition and the
1004 // strong definition into the dynamic symbol table. Given a weak
1005 // definition, the only way that we can find the corresponding
1006 // strong definition, if any, is to search the symbol table.
1007 std::vector<Sized_symbol<size>*> object_symbols;
1009 const unsigned char* p = syms;
1010 const unsigned char* vs = versym;
1011 for (size_t i = 0; i < count; ++i, p += sym_size, vs += 2)
1013 elfcpp::Sym<size, big_endian> sym(p);
1015 // Ignore symbols with local binding or that have
1016 // internal or hidden visibility.
1017 if (sym.get_st_bind() == elfcpp::STB_LOCAL
1018 || sym.get_st_visibility() == elfcpp::STV_INTERNAL
1019 || sym.get_st_visibility() == elfcpp::STV_HIDDEN)
1020 continue;
1022 // A protected symbol in a shared library must be treated as a
1023 // normal symbol when viewed from outside the shared library.
1024 // Implement this by overriding the visibility here.
1025 elfcpp::Sym<size, big_endian>* psym = &sym;
1026 unsigned char symbuf[sym_size];
1027 elfcpp::Sym<size, big_endian> sym2(symbuf);
1028 if (sym.get_st_visibility() == elfcpp::STV_PROTECTED)
1030 memcpy(symbuf, p, sym_size);
1031 elfcpp::Sym_write<size, big_endian> sw(symbuf);
1032 sw.put_st_other(elfcpp::STV_DEFAULT, sym.get_st_nonvis());
1033 psym = &sym2;
1036 unsigned int st_name = psym->get_st_name();
1037 if (st_name >= sym_name_size)
1039 dynobj->error(_("bad symbol name offset %u at %zu"),
1040 st_name, i);
1041 continue;
1044 const char* name = sym_names + st_name;
1046 bool is_ordinary;
1047 unsigned int st_shndx = dynobj->adjust_sym_shndx(i, psym->get_st_shndx(),
1048 &is_ordinary);
1050 Sized_symbol<size>* res;
1052 if (versym == NULL)
1054 Stringpool::Key name_key;
1055 name = this->namepool_.add(name, true, &name_key);
1056 res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1057 false, *psym, st_shndx, is_ordinary,
1058 st_shndx);
1060 else
1062 // Read the version information.
1064 unsigned int v = elfcpp::Swap<16, big_endian>::readval(vs);
1066 bool hidden = (v & elfcpp::VERSYM_HIDDEN) != 0;
1067 v &= elfcpp::VERSYM_VERSION;
1069 // The Sun documentation says that V can be VER_NDX_LOCAL,
1070 // or VER_NDX_GLOBAL, or a version index. The meaning of
1071 // VER_NDX_LOCAL is defined as "Symbol has local scope."
1072 // The old GNU linker will happily generate VER_NDX_LOCAL
1073 // for an undefined symbol. I don't know what the Sun
1074 // linker will generate.
1076 if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1077 && st_shndx != elfcpp::SHN_UNDEF)
1079 // This symbol should not be visible outside the object.
1080 continue;
1083 // At this point we are definitely going to add this symbol.
1084 Stringpool::Key name_key;
1085 name = this->namepool_.add(name, true, &name_key);
1087 if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL)
1088 || v == static_cast<unsigned int>(elfcpp::VER_NDX_GLOBAL))
1090 // This symbol does not have a version.
1091 res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1092 false, *psym, st_shndx, is_ordinary,
1093 st_shndx);
1095 else
1097 if (v >= version_map->size())
1099 dynobj->error(_("versym for symbol %zu out of range: %u"),
1100 i, v);
1101 continue;
1104 const char* version = (*version_map)[v];
1105 if (version == NULL)
1107 dynobj->error(_("versym for symbol %zu has no name: %u"),
1108 i, v);
1109 continue;
1112 Stringpool::Key version_key;
1113 version = this->namepool_.add(version, true, &version_key);
1115 // If this is an absolute symbol, and the version name
1116 // and symbol name are the same, then this is the
1117 // version definition symbol. These symbols exist to
1118 // support using -u to pull in particular versions. We
1119 // do not want to record a version for them.
1120 if (st_shndx == elfcpp::SHN_ABS
1121 && !is_ordinary
1122 && name_key == version_key)
1123 res = this->add_from_object(dynobj, name, name_key, NULL, 0,
1124 false, *psym, st_shndx, is_ordinary,
1125 st_shndx);
1126 else
1128 const bool def = (!hidden
1129 && st_shndx != elfcpp::SHN_UNDEF);
1130 res = this->add_from_object(dynobj, name, name_key, version,
1131 version_key, def, *psym, st_shndx,
1132 is_ordinary, st_shndx);
1137 // Note that it is possible that RES was overridden by an
1138 // earlier object, in which case it can't be aliased here.
1139 if (st_shndx != elfcpp::SHN_UNDEF
1140 && is_ordinary
1141 && psym->get_st_type() == elfcpp::STT_OBJECT
1142 && res->source() == Symbol::FROM_OBJECT
1143 && res->object() == dynobj)
1144 object_symbols.push_back(res);
1147 this->record_weak_aliases(&object_symbols);
1150 // This is used to sort weak aliases. We sort them first by section
1151 // index, then by offset, then by weak ahead of strong.
1153 template<int size>
1154 class Weak_alias_sorter
1156 public:
1157 bool operator()(const Sized_symbol<size>*, const Sized_symbol<size>*) const;
1160 template<int size>
1161 bool
1162 Weak_alias_sorter<size>::operator()(const Sized_symbol<size>* s1,
1163 const Sized_symbol<size>* s2) const
1165 bool is_ordinary;
1166 unsigned int s1_shndx = s1->shndx(&is_ordinary);
1167 gold_assert(is_ordinary);
1168 unsigned int s2_shndx = s2->shndx(&is_ordinary);
1169 gold_assert(is_ordinary);
1170 if (s1_shndx != s2_shndx)
1171 return s1_shndx < s2_shndx;
1173 if (s1->value() != s2->value())
1174 return s1->value() < s2->value();
1175 if (s1->binding() != s2->binding())
1177 if (s1->binding() == elfcpp::STB_WEAK)
1178 return true;
1179 if (s2->binding() == elfcpp::STB_WEAK)
1180 return false;
1182 return std::string(s1->name()) < std::string(s2->name());
1185 // SYMBOLS is a list of object symbols from a dynamic object. Look
1186 // for any weak aliases, and record them so that if we add the weak
1187 // alias to the dynamic symbol table, we also add the corresponding
1188 // strong symbol.
1190 template<int size>
1191 void
1192 Symbol_table::record_weak_aliases(std::vector<Sized_symbol<size>*>* symbols)
1194 // Sort the vector by section index, then by offset, then by weak
1195 // ahead of strong.
1196 std::sort(symbols->begin(), symbols->end(), Weak_alias_sorter<size>());
1198 // Walk through the vector. For each weak definition, record
1199 // aliases.
1200 for (typename std::vector<Sized_symbol<size>*>::const_iterator p =
1201 symbols->begin();
1202 p != symbols->end();
1203 ++p)
1205 if ((*p)->binding() != elfcpp::STB_WEAK)
1206 continue;
1208 // Build a circular list of weak aliases. Each symbol points to
1209 // the next one in the circular list.
1211 Sized_symbol<size>* from_sym = *p;
1212 typename std::vector<Sized_symbol<size>*>::const_iterator q;
1213 for (q = p + 1; q != symbols->end(); ++q)
1215 bool dummy;
1216 if ((*q)->shndx(&dummy) != from_sym->shndx(&dummy)
1217 || (*q)->value() != from_sym->value())
1218 break;
1220 this->weak_aliases_[from_sym] = *q;
1221 from_sym->set_has_alias();
1222 from_sym = *q;
1225 if (from_sym != *p)
1227 this->weak_aliases_[from_sym] = *p;
1228 from_sym->set_has_alias();
1231 p = q - 1;
1235 // Create and return a specially defined symbol. If ONLY_IF_REF is
1236 // true, then only create the symbol if there is a reference to it.
1237 // If this does not return NULL, it sets *POLDSYM to the existing
1238 // symbol if there is one. This canonicalizes *PNAME and *PVERSION.
1240 template<int size, bool big_endian>
1241 Sized_symbol<size>*
1242 Symbol_table::define_special_symbol(const char** pname, const char** pversion,
1243 bool only_if_ref,
1244 Sized_symbol<size>** poldsym)
1246 Symbol* oldsym;
1247 Sized_symbol<size>* sym;
1248 bool add_to_table = false;
1249 typename Symbol_table_type::iterator add_loc = this->table_.end();
1251 // If the caller didn't give us a version, see if we get one from
1252 // the version script.
1253 if (*pversion == NULL)
1255 const std::string& v(this->version_script_.get_symbol_version(*pname));
1256 if (!v.empty())
1257 *pversion = v.c_str();
1260 if (only_if_ref)
1262 oldsym = this->lookup(*pname, *pversion);
1263 if (oldsym == NULL || !oldsym->is_undefined())
1264 return NULL;
1266 *pname = oldsym->name();
1267 *pversion = oldsym->version();
1269 else
1271 // Canonicalize NAME and VERSION.
1272 Stringpool::Key name_key;
1273 *pname = this->namepool_.add(*pname, true, &name_key);
1275 Stringpool::Key version_key = 0;
1276 if (*pversion != NULL)
1277 *pversion = this->namepool_.add(*pversion, true, &version_key);
1279 Symbol* const snull = NULL;
1280 std::pair<typename Symbol_table_type::iterator, bool> ins =
1281 this->table_.insert(std::make_pair(std::make_pair(name_key,
1282 version_key),
1283 snull));
1285 if (!ins.second)
1287 // We already have a symbol table entry for NAME/VERSION.
1288 oldsym = ins.first->second;
1289 gold_assert(oldsym != NULL);
1291 else
1293 // We haven't seen this symbol before.
1294 gold_assert(ins.first->second == NULL);
1295 add_to_table = true;
1296 add_loc = ins.first;
1297 oldsym = NULL;
1301 const Target& target = parameters->target();
1302 if (!target.has_make_symbol())
1303 sym = new Sized_symbol<size>();
1304 else
1306 gold_assert(target.get_size() == size);
1307 gold_assert(target.is_big_endian() ? big_endian : !big_endian);
1308 typedef Sized_target<size, big_endian> My_target;
1309 const My_target* sized_target =
1310 static_cast<const My_target*>(&target);
1311 sym = sized_target->make_symbol();
1312 if (sym == NULL)
1313 return NULL;
1316 if (add_to_table)
1317 add_loc->second = sym;
1318 else
1319 gold_assert(oldsym != NULL);
1321 *poldsym = this->get_sized_symbol<size>(oldsym);
1323 return sym;
1326 // Define a symbol based on an Output_data.
1328 Symbol*
1329 Symbol_table::define_in_output_data(const char* name,
1330 const char* version,
1331 Output_data* od,
1332 uint64_t value,
1333 uint64_t symsize,
1334 elfcpp::STT type,
1335 elfcpp::STB binding,
1336 elfcpp::STV visibility,
1337 unsigned char nonvis,
1338 bool offset_is_from_end,
1339 bool only_if_ref)
1341 if (parameters->target().get_size() == 32)
1343 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1344 return this->do_define_in_output_data<32>(name, version, od,
1345 value, symsize, type, binding,
1346 visibility, nonvis,
1347 offset_is_from_end,
1348 only_if_ref);
1349 #else
1350 gold_unreachable();
1351 #endif
1353 else if (parameters->target().get_size() == 64)
1355 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1356 return this->do_define_in_output_data<64>(name, version, od,
1357 value, symsize, type, binding,
1358 visibility, nonvis,
1359 offset_is_from_end,
1360 only_if_ref);
1361 #else
1362 gold_unreachable();
1363 #endif
1365 else
1366 gold_unreachable();
1369 // Define a symbol in an Output_data, sized version.
1371 template<int size>
1372 Sized_symbol<size>*
1373 Symbol_table::do_define_in_output_data(
1374 const char* name,
1375 const char* version,
1376 Output_data* od,
1377 typename elfcpp::Elf_types<size>::Elf_Addr value,
1378 typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1379 elfcpp::STT type,
1380 elfcpp::STB binding,
1381 elfcpp::STV visibility,
1382 unsigned char nonvis,
1383 bool offset_is_from_end,
1384 bool only_if_ref)
1386 Sized_symbol<size>* sym;
1387 Sized_symbol<size>* oldsym;
1389 if (parameters->target().is_big_endian())
1391 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1392 sym = this->define_special_symbol<size, true>(&name, &version,
1393 only_if_ref, &oldsym);
1394 #else
1395 gold_unreachable();
1396 #endif
1398 else
1400 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1401 sym = this->define_special_symbol<size, false>(&name, &version,
1402 only_if_ref, &oldsym);
1403 #else
1404 gold_unreachable();
1405 #endif
1408 if (sym == NULL)
1409 return NULL;
1411 sym->init_output_data(name, version, od, value, symsize, type, binding,
1412 visibility, nonvis, offset_is_from_end);
1414 if (oldsym == NULL)
1416 if (binding == elfcpp::STB_LOCAL
1417 || this->version_script_.symbol_is_local(name))
1418 this->force_local(sym);
1419 else if (version != NULL)
1420 sym->set_is_default();
1421 return sym;
1424 if (Symbol_table::should_override_with_special(oldsym))
1425 this->override_with_special(oldsym, sym);
1426 delete sym;
1427 return oldsym;
1430 // Define a symbol based on an Output_segment.
1432 Symbol*
1433 Symbol_table::define_in_output_segment(const char* name,
1434 const char* version, Output_segment* os,
1435 uint64_t value,
1436 uint64_t symsize,
1437 elfcpp::STT type,
1438 elfcpp::STB binding,
1439 elfcpp::STV visibility,
1440 unsigned char nonvis,
1441 Symbol::Segment_offset_base offset_base,
1442 bool only_if_ref)
1444 if (parameters->target().get_size() == 32)
1446 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1447 return this->do_define_in_output_segment<32>(name, version, os,
1448 value, symsize, type,
1449 binding, visibility, nonvis,
1450 offset_base, only_if_ref);
1451 #else
1452 gold_unreachable();
1453 #endif
1455 else if (parameters->target().get_size() == 64)
1457 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1458 return this->do_define_in_output_segment<64>(name, version, os,
1459 value, symsize, type,
1460 binding, visibility, nonvis,
1461 offset_base, only_if_ref);
1462 #else
1463 gold_unreachable();
1464 #endif
1466 else
1467 gold_unreachable();
1470 // Define a symbol in an Output_segment, sized version.
1472 template<int size>
1473 Sized_symbol<size>*
1474 Symbol_table::do_define_in_output_segment(
1475 const char* name,
1476 const char* version,
1477 Output_segment* os,
1478 typename elfcpp::Elf_types<size>::Elf_Addr value,
1479 typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1480 elfcpp::STT type,
1481 elfcpp::STB binding,
1482 elfcpp::STV visibility,
1483 unsigned char nonvis,
1484 Symbol::Segment_offset_base offset_base,
1485 bool only_if_ref)
1487 Sized_symbol<size>* sym;
1488 Sized_symbol<size>* oldsym;
1490 if (parameters->target().is_big_endian())
1492 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1493 sym = this->define_special_symbol<size, true>(&name, &version,
1494 only_if_ref, &oldsym);
1495 #else
1496 gold_unreachable();
1497 #endif
1499 else
1501 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1502 sym = this->define_special_symbol<size, false>(&name, &version,
1503 only_if_ref, &oldsym);
1504 #else
1505 gold_unreachable();
1506 #endif
1509 if (sym == NULL)
1510 return NULL;
1512 sym->init_output_segment(name, version, os, value, symsize, type, binding,
1513 visibility, nonvis, offset_base);
1515 if (oldsym == NULL)
1517 if (binding == elfcpp::STB_LOCAL
1518 || this->version_script_.symbol_is_local(name))
1519 this->force_local(sym);
1520 else if (version != NULL)
1521 sym->set_is_default();
1522 return sym;
1525 if (Symbol_table::should_override_with_special(oldsym))
1526 this->override_with_special(oldsym, sym);
1527 delete sym;
1528 return oldsym;
1531 // Define a special symbol with a constant value. It is a multiple
1532 // definition error if this symbol is already defined.
1534 Symbol*
1535 Symbol_table::define_as_constant(const char* name,
1536 const char* version,
1537 uint64_t value,
1538 uint64_t symsize,
1539 elfcpp::STT type,
1540 elfcpp::STB binding,
1541 elfcpp::STV visibility,
1542 unsigned char nonvis,
1543 bool only_if_ref,
1544 bool force_override)
1546 if (parameters->target().get_size() == 32)
1548 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1549 return this->do_define_as_constant<32>(name, version, value,
1550 symsize, type, binding,
1551 visibility, nonvis, only_if_ref,
1552 force_override);
1553 #else
1554 gold_unreachable();
1555 #endif
1557 else if (parameters->target().get_size() == 64)
1559 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1560 return this->do_define_as_constant<64>(name, version, value,
1561 symsize, type, binding,
1562 visibility, nonvis, only_if_ref,
1563 force_override);
1564 #else
1565 gold_unreachable();
1566 #endif
1568 else
1569 gold_unreachable();
1572 // Define a symbol as a constant, sized version.
1574 template<int size>
1575 Sized_symbol<size>*
1576 Symbol_table::do_define_as_constant(
1577 const char* name,
1578 const char* version,
1579 typename elfcpp::Elf_types<size>::Elf_Addr value,
1580 typename elfcpp::Elf_types<size>::Elf_WXword symsize,
1581 elfcpp::STT type,
1582 elfcpp::STB binding,
1583 elfcpp::STV visibility,
1584 unsigned char nonvis,
1585 bool only_if_ref,
1586 bool force_override)
1588 Sized_symbol<size>* sym;
1589 Sized_symbol<size>* oldsym;
1591 if (parameters->target().is_big_endian())
1593 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1594 sym = this->define_special_symbol<size, true>(&name, &version,
1595 only_if_ref, &oldsym);
1596 #else
1597 gold_unreachable();
1598 #endif
1600 else
1602 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1603 sym = this->define_special_symbol<size, false>(&name, &version,
1604 only_if_ref, &oldsym);
1605 #else
1606 gold_unreachable();
1607 #endif
1610 if (sym == NULL)
1611 return NULL;
1613 sym->init_constant(name, version, value, symsize, type, binding, visibility,
1614 nonvis);
1616 if (oldsym == NULL)
1618 // Version symbols are absolute symbols with name == version.
1619 // We don't want to force them to be local.
1620 if ((version == NULL
1621 || name != version
1622 || value != 0)
1623 && (binding == elfcpp::STB_LOCAL
1624 || this->version_script_.symbol_is_local(name)))
1625 this->force_local(sym);
1626 else if (version != NULL
1627 && (name != version || value != 0))
1628 sym->set_is_default();
1629 return sym;
1632 if (force_override || Symbol_table::should_override_with_special(oldsym))
1633 this->override_with_special(oldsym, sym);
1634 delete sym;
1635 return oldsym;
1638 // Define a set of symbols in output sections.
1640 void
1641 Symbol_table::define_symbols(const Layout* layout, int count,
1642 const Define_symbol_in_section* p,
1643 bool only_if_ref)
1645 for (int i = 0; i < count; ++i, ++p)
1647 Output_section* os = layout->find_output_section(p->output_section);
1648 if (os != NULL)
1649 this->define_in_output_data(p->name, NULL, os, p->value,
1650 p->size, p->type, p->binding,
1651 p->visibility, p->nonvis,
1652 p->offset_is_from_end,
1653 only_if_ref || p->only_if_ref);
1654 else
1655 this->define_as_constant(p->name, NULL, 0, p->size, p->type,
1656 p->binding, p->visibility, p->nonvis,
1657 only_if_ref || p->only_if_ref,
1658 false);
1662 // Define a set of symbols in output segments.
1664 void
1665 Symbol_table::define_symbols(const Layout* layout, int count,
1666 const Define_symbol_in_segment* p,
1667 bool only_if_ref)
1669 for (int i = 0; i < count; ++i, ++p)
1671 Output_segment* os = layout->find_output_segment(p->segment_type,
1672 p->segment_flags_set,
1673 p->segment_flags_clear);
1674 if (os != NULL)
1675 this->define_in_output_segment(p->name, NULL, os, p->value,
1676 p->size, p->type, p->binding,
1677 p->visibility, p->nonvis,
1678 p->offset_base,
1679 only_if_ref || p->only_if_ref);
1680 else
1681 this->define_as_constant(p->name, NULL, 0, p->size, p->type,
1682 p->binding, p->visibility, p->nonvis,
1683 only_if_ref || p->only_if_ref,
1684 false);
1688 // Define CSYM using a COPY reloc. POSD is the Output_data where the
1689 // symbol should be defined--typically a .dyn.bss section. VALUE is
1690 // the offset within POSD.
1692 template<int size>
1693 void
1694 Symbol_table::define_with_copy_reloc(
1695 Sized_symbol<size>* csym,
1696 Output_data* posd,
1697 typename elfcpp::Elf_types<size>::Elf_Addr value)
1699 gold_assert(csym->is_from_dynobj());
1700 gold_assert(!csym->is_copied_from_dynobj());
1701 Object* object = csym->object();
1702 gold_assert(object->is_dynamic());
1703 Dynobj* dynobj = static_cast<Dynobj*>(object);
1705 // Our copied variable has to override any variable in a shared
1706 // library.
1707 elfcpp::STB binding = csym->binding();
1708 if (binding == elfcpp::STB_WEAK)
1709 binding = elfcpp::STB_GLOBAL;
1711 this->define_in_output_data(csym->name(), csym->version(),
1712 posd, value, csym->symsize(),
1713 csym->type(), binding,
1714 csym->visibility(), csym->nonvis(),
1715 false, false);
1717 csym->set_is_copied_from_dynobj();
1718 csym->set_needs_dynsym_entry();
1720 this->copied_symbol_dynobjs_[csym] = dynobj;
1722 // We have now defined all aliases, but we have not entered them all
1723 // in the copied_symbol_dynobjs_ map.
1724 if (csym->has_alias())
1726 Symbol* sym = csym;
1727 while (true)
1729 sym = this->weak_aliases_[sym];
1730 if (sym == csym)
1731 break;
1732 gold_assert(sym->output_data() == posd);
1734 sym->set_is_copied_from_dynobj();
1735 this->copied_symbol_dynobjs_[sym] = dynobj;
1740 // SYM is defined using a COPY reloc. Return the dynamic object where
1741 // the original definition was found.
1743 Dynobj*
1744 Symbol_table::get_copy_source(const Symbol* sym) const
1746 gold_assert(sym->is_copied_from_dynobj());
1747 Copied_symbol_dynobjs::const_iterator p =
1748 this->copied_symbol_dynobjs_.find(sym);
1749 gold_assert(p != this->copied_symbol_dynobjs_.end());
1750 return p->second;
1753 // Add any undefined symbols named on the command line.
1755 void
1756 Symbol_table::add_undefined_symbols_from_command_line()
1758 if (parameters->options().any_undefined())
1760 if (parameters->target().get_size() == 32)
1762 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
1763 this->do_add_undefined_symbols_from_command_line<32>();
1764 #else
1765 gold_unreachable();
1766 #endif
1768 else if (parameters->target().get_size() == 64)
1770 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
1771 this->do_add_undefined_symbols_from_command_line<64>();
1772 #else
1773 gold_unreachable();
1774 #endif
1776 else
1777 gold_unreachable();
1781 template<int size>
1782 void
1783 Symbol_table::do_add_undefined_symbols_from_command_line()
1785 for (options::String_set::const_iterator p =
1786 parameters->options().undefined_begin();
1787 p != parameters->options().undefined_end();
1788 ++p)
1790 const char* name = p->c_str();
1792 if (this->lookup(name) != NULL)
1793 continue;
1795 const char* version = NULL;
1797 Sized_symbol<size>* sym;
1798 Sized_symbol<size>* oldsym;
1799 if (parameters->target().is_big_endian())
1801 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG)
1802 sym = this->define_special_symbol<size, true>(&name, &version,
1803 false, &oldsym);
1804 #else
1805 gold_unreachable();
1806 #endif
1808 else
1810 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE)
1811 sym = this->define_special_symbol<size, false>(&name, &version,
1812 false, &oldsym);
1813 #else
1814 gold_unreachable();
1815 #endif
1818 gold_assert(oldsym == NULL);
1820 sym->init_undefined(name, version, elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
1821 elfcpp::STV_DEFAULT, 0);
1822 ++this->saw_undefined_;
1826 // Set the dynamic symbol indexes. INDEX is the index of the first
1827 // global dynamic symbol. Pointers to the symbols are stored into the
1828 // vector SYMS. The names are added to DYNPOOL. This returns an
1829 // updated dynamic symbol index.
1831 unsigned int
1832 Symbol_table::set_dynsym_indexes(unsigned int index,
1833 std::vector<Symbol*>* syms,
1834 Stringpool* dynpool,
1835 Versions* versions)
1837 for (Symbol_table_type::iterator p = this->table_.begin();
1838 p != this->table_.end();
1839 ++p)
1841 Symbol* sym = p->second;
1843 // Note that SYM may already have a dynamic symbol index, since
1844 // some symbols appear more than once in the symbol table, with
1845 // and without a version.
1847 if (!sym->should_add_dynsym_entry())
1848 sym->set_dynsym_index(-1U);
1849 else if (!sym->has_dynsym_index())
1851 sym->set_dynsym_index(index);
1852 ++index;
1853 syms->push_back(sym);
1854 dynpool->add(sym->name(), false, NULL);
1856 // Record any version information.
1857 if (sym->version() != NULL)
1858 versions->record_version(this, dynpool, sym);
1862 // Finish up the versions. In some cases this may add new dynamic
1863 // symbols.
1864 index = versions->finalize(this, index, syms);
1866 return index;
1869 // Set the final values for all the symbols. The index of the first
1870 // global symbol in the output file is *PLOCAL_SYMCOUNT. Record the
1871 // file offset OFF. Add their names to POOL. Return the new file
1872 // offset. Update *PLOCAL_SYMCOUNT if necessary.
1874 off_t
1875 Symbol_table::finalize(off_t off, off_t dynoff, size_t dyn_global_index,
1876 size_t dyncount, Stringpool* pool,
1877 unsigned int *plocal_symcount)
1879 off_t ret;
1881 gold_assert(*plocal_symcount != 0);
1882 this->first_global_index_ = *plocal_symcount;
1884 this->dynamic_offset_ = dynoff;
1885 this->first_dynamic_global_index_ = dyn_global_index;
1886 this->dynamic_count_ = dyncount;
1888 if (parameters->target().get_size() == 32)
1890 #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_32_LITTLE)
1891 ret = this->sized_finalize<32>(off, pool, plocal_symcount);
1892 #else
1893 gold_unreachable();
1894 #endif
1896 else if (parameters->target().get_size() == 64)
1898 #if defined(HAVE_TARGET_64_BIG) || defined(HAVE_TARGET_64_LITTLE)
1899 ret = this->sized_finalize<64>(off, pool, plocal_symcount);
1900 #else
1901 gold_unreachable();
1902 #endif
1904 else
1905 gold_unreachable();
1907 // Now that we have the final symbol table, we can reliably note
1908 // which symbols should get warnings.
1909 this->warnings_.note_warnings(this);
1911 return ret;
1914 // SYM is going into the symbol table at *PINDEX. Add the name to
1915 // POOL, update *PINDEX and *POFF.
1917 template<int size>
1918 void
1919 Symbol_table::add_to_final_symtab(Symbol* sym, Stringpool* pool,
1920 unsigned int* pindex, off_t* poff)
1922 sym->set_symtab_index(*pindex);
1923 pool->add(sym->name(), false, NULL);
1924 ++*pindex;
1925 *poff += elfcpp::Elf_sizes<size>::sym_size;
1928 // Set the final value for all the symbols. This is called after
1929 // Layout::finalize, so all the output sections have their final
1930 // address.
1932 template<int size>
1933 off_t
1934 Symbol_table::sized_finalize(off_t off, Stringpool* pool,
1935 unsigned int* plocal_symcount)
1937 off = align_address(off, size >> 3);
1938 this->offset_ = off;
1940 unsigned int index = *plocal_symcount;
1941 const unsigned int orig_index = index;
1943 // First do all the symbols which have been forced to be local, as
1944 // they must appear before all global symbols.
1945 for (Forced_locals::iterator p = this->forced_locals_.begin();
1946 p != this->forced_locals_.end();
1947 ++p)
1949 Symbol* sym = *p;
1950 gold_assert(sym->is_forced_local());
1951 if (this->sized_finalize_symbol<size>(sym))
1953 this->add_to_final_symtab<size>(sym, pool, &index, &off);
1954 ++*plocal_symcount;
1958 // Now do all the remaining symbols.
1959 for (Symbol_table_type::iterator p = this->table_.begin();
1960 p != this->table_.end();
1961 ++p)
1963 Symbol* sym = p->second;
1964 if (this->sized_finalize_symbol<size>(sym))
1965 this->add_to_final_symtab<size>(sym, pool, &index, &off);
1968 this->output_count_ = index - orig_index;
1970 return off;
1973 // Finalize the symbol SYM. This returns true if the symbol should be
1974 // added to the symbol table, false otherwise.
1976 template<int size>
1977 bool
1978 Symbol_table::sized_finalize_symbol(Symbol* unsized_sym)
1980 typedef typename Sized_symbol<size>::Value_type Value_type;
1982 Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(unsized_sym);
1984 // The default version of a symbol may appear twice in the symbol
1985 // table. We only need to finalize it once.
1986 if (sym->has_symtab_index())
1987 return false;
1989 if (!sym->in_reg())
1991 gold_assert(!sym->has_symtab_index());
1992 sym->set_symtab_index(-1U);
1993 gold_assert(sym->dynsym_index() == -1U);
1994 return false;
1997 Value_type value;
1999 switch (sym->source())
2001 case Symbol::FROM_OBJECT:
2003 bool is_ordinary;
2004 unsigned int shndx = sym->shndx(&is_ordinary);
2006 // FIXME: We need some target specific support here.
2007 if (!is_ordinary
2008 && shndx != elfcpp::SHN_ABS
2009 && shndx != elfcpp::SHN_COMMON)
2011 gold_error(_("%s: unsupported symbol section 0x%x"),
2012 sym->demangled_name().c_str(), shndx);
2013 shndx = elfcpp::SHN_UNDEF;
2016 Object* symobj = sym->object();
2017 if (symobj->is_dynamic())
2019 value = 0;
2020 shndx = elfcpp::SHN_UNDEF;
2022 else if (shndx == elfcpp::SHN_UNDEF)
2023 value = 0;
2024 else if (!is_ordinary
2025 && (shndx == elfcpp::SHN_ABS || shndx == elfcpp::SHN_COMMON))
2026 value = sym->value();
2027 else
2029 Relobj* relobj = static_cast<Relobj*>(symobj);
2030 Output_section* os = relobj->output_section(shndx);
2032 if (os == NULL)
2034 sym->set_symtab_index(-1U);
2035 gold_assert(sym->dynsym_index() == -1U);
2036 return false;
2039 uint64_t secoff64 = relobj->output_section_offset(shndx);
2040 Value_type secoff = convert_types<Value_type, uint64_t>(secoff64);
2041 if (sym->type() == elfcpp::STT_TLS)
2042 value = sym->value() + os->tls_offset() + secoff;
2043 else
2044 value = sym->value() + os->address() + secoff;
2047 break;
2049 case Symbol::IN_OUTPUT_DATA:
2051 Output_data* od = sym->output_data();
2052 value = sym->value();
2053 if (sym->type() != elfcpp::STT_TLS)
2054 value += od->address();
2055 else
2057 Output_section* os = od->output_section();
2058 gold_assert(os != NULL);
2059 value += os->tls_offset() + (od->address() - os->address());
2061 if (sym->offset_is_from_end())
2062 value += od->data_size();
2064 break;
2066 case Symbol::IN_OUTPUT_SEGMENT:
2068 Output_segment* os = sym->output_segment();
2069 value = sym->value();
2070 if (sym->type() != elfcpp::STT_TLS)
2071 value += os->vaddr();
2072 switch (sym->offset_base())
2074 case Symbol::SEGMENT_START:
2075 break;
2076 case Symbol::SEGMENT_END:
2077 value += os->memsz();
2078 break;
2079 case Symbol::SEGMENT_BSS:
2080 value += os->filesz();
2081 break;
2082 default:
2083 gold_unreachable();
2086 break;
2088 case Symbol::IS_CONSTANT:
2089 value = sym->value();
2090 break;
2092 case Symbol::IS_UNDEFINED:
2093 value = 0;
2094 break;
2096 default:
2097 gold_unreachable();
2100 sym->set_value(value);
2102 if (parameters->options().strip_all())
2104 sym->set_symtab_index(-1U);
2105 return false;
2108 return true;
2111 // Write out the global symbols.
2113 void
2114 Symbol_table::write_globals(const Input_objects* input_objects,
2115 const Stringpool* sympool,
2116 const Stringpool* dynpool,
2117 Output_symtab_xindex* symtab_xindex,
2118 Output_symtab_xindex* dynsym_xindex,
2119 Output_file* of) const
2121 switch (parameters->size_and_endianness())
2123 #ifdef HAVE_TARGET_32_LITTLE
2124 case Parameters::TARGET_32_LITTLE:
2125 this->sized_write_globals<32, false>(input_objects, sympool,
2126 dynpool, symtab_xindex,
2127 dynsym_xindex, of);
2128 break;
2129 #endif
2130 #ifdef HAVE_TARGET_32_BIG
2131 case Parameters::TARGET_32_BIG:
2132 this->sized_write_globals<32, true>(input_objects, sympool,
2133 dynpool, symtab_xindex,
2134 dynsym_xindex, of);
2135 break;
2136 #endif
2137 #ifdef HAVE_TARGET_64_LITTLE
2138 case Parameters::TARGET_64_LITTLE:
2139 this->sized_write_globals<64, false>(input_objects, sympool,
2140 dynpool, symtab_xindex,
2141 dynsym_xindex, of);
2142 break;
2143 #endif
2144 #ifdef HAVE_TARGET_64_BIG
2145 case Parameters::TARGET_64_BIG:
2146 this->sized_write_globals<64, true>(input_objects, sympool,
2147 dynpool, symtab_xindex,
2148 dynsym_xindex, of);
2149 break;
2150 #endif
2151 default:
2152 gold_unreachable();
2156 // Write out the global symbols.
2158 template<int size, bool big_endian>
2159 void
2160 Symbol_table::sized_write_globals(const Input_objects* input_objects,
2161 const Stringpool* sympool,
2162 const Stringpool* dynpool,
2163 Output_symtab_xindex* symtab_xindex,
2164 Output_symtab_xindex* dynsym_xindex,
2165 Output_file* of) const
2167 const Target& target = parameters->target();
2169 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2171 const unsigned int output_count = this->output_count_;
2172 const section_size_type oview_size = output_count * sym_size;
2173 const unsigned int first_global_index = this->first_global_index_;
2174 unsigned char* psyms;
2175 if (this->offset_ == 0 || output_count == 0)
2176 psyms = NULL;
2177 else
2178 psyms = of->get_output_view(this->offset_, oview_size);
2180 const unsigned int dynamic_count = this->dynamic_count_;
2181 const section_size_type dynamic_size = dynamic_count * sym_size;
2182 const unsigned int first_dynamic_global_index =
2183 this->first_dynamic_global_index_;
2184 unsigned char* dynamic_view;
2185 if (this->dynamic_offset_ == 0 || dynamic_count == 0)
2186 dynamic_view = NULL;
2187 else
2188 dynamic_view = of->get_output_view(this->dynamic_offset_, dynamic_size);
2190 for (Symbol_table_type::const_iterator p = this->table_.begin();
2191 p != this->table_.end();
2192 ++p)
2194 Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second);
2196 // Possibly warn about unresolved symbols in shared libraries.
2197 this->warn_about_undefined_dynobj_symbol(input_objects, sym);
2199 unsigned int sym_index = sym->symtab_index();
2200 unsigned int dynsym_index;
2201 if (dynamic_view == NULL)
2202 dynsym_index = -1U;
2203 else
2204 dynsym_index = sym->dynsym_index();
2206 if (sym_index == -1U && dynsym_index == -1U)
2208 // This symbol is not included in the output file.
2209 continue;
2212 unsigned int shndx;
2213 typename elfcpp::Elf_types<size>::Elf_Addr sym_value = sym->value();
2214 typename elfcpp::Elf_types<size>::Elf_Addr dynsym_value = sym_value;
2215 switch (sym->source())
2217 case Symbol::FROM_OBJECT:
2219 bool is_ordinary;
2220 unsigned int in_shndx = sym->shndx(&is_ordinary);
2222 // FIXME: We need some target specific support here.
2223 if (!is_ordinary
2224 && in_shndx != elfcpp::SHN_ABS
2225 && in_shndx != elfcpp::SHN_COMMON)
2227 gold_error(_("%s: unsupported symbol section 0x%x"),
2228 sym->demangled_name().c_str(), in_shndx);
2229 shndx = in_shndx;
2231 else
2233 Object* symobj = sym->object();
2234 if (symobj->is_dynamic())
2236 if (sym->needs_dynsym_value())
2237 dynsym_value = target.dynsym_value(sym);
2238 shndx = elfcpp::SHN_UNDEF;
2240 else if (in_shndx == elfcpp::SHN_UNDEF
2241 || (!is_ordinary
2242 && (in_shndx == elfcpp::SHN_ABS
2243 || in_shndx == elfcpp::SHN_COMMON)))
2244 shndx = in_shndx;
2245 else
2247 Relobj* relobj = static_cast<Relobj*>(symobj);
2248 Output_section* os = relobj->output_section(in_shndx);
2249 gold_assert(os != NULL);
2250 shndx = os->out_shndx();
2252 if (shndx >= elfcpp::SHN_LORESERVE)
2254 if (sym_index != -1U)
2255 symtab_xindex->add(sym_index, shndx);
2256 if (dynsym_index != -1U)
2257 dynsym_xindex->add(dynsym_index, shndx);
2258 shndx = elfcpp::SHN_XINDEX;
2261 // In object files symbol values are section
2262 // relative.
2263 if (parameters->options().relocatable())
2264 sym_value -= os->address();
2268 break;
2270 case Symbol::IN_OUTPUT_DATA:
2271 shndx = sym->output_data()->out_shndx();
2272 if (shndx >= elfcpp::SHN_LORESERVE)
2274 if (sym_index != -1U)
2275 symtab_xindex->add(sym_index, shndx);
2276 if (dynsym_index != -1U)
2277 dynsym_xindex->add(dynsym_index, shndx);
2278 shndx = elfcpp::SHN_XINDEX;
2280 break;
2282 case Symbol::IN_OUTPUT_SEGMENT:
2283 shndx = elfcpp::SHN_ABS;
2284 break;
2286 case Symbol::IS_CONSTANT:
2287 shndx = elfcpp::SHN_ABS;
2288 break;
2290 case Symbol::IS_UNDEFINED:
2291 shndx = elfcpp::SHN_UNDEF;
2292 break;
2294 default:
2295 gold_unreachable();
2298 if (sym_index != -1U)
2300 sym_index -= first_global_index;
2301 gold_assert(sym_index < output_count);
2302 unsigned char* ps = psyms + (sym_index * sym_size);
2303 this->sized_write_symbol<size, big_endian>(sym, sym_value, shndx,
2304 sympool, ps);
2307 if (dynsym_index != -1U)
2309 dynsym_index -= first_dynamic_global_index;
2310 gold_assert(dynsym_index < dynamic_count);
2311 unsigned char* pd = dynamic_view + (dynsym_index * sym_size);
2312 this->sized_write_symbol<size, big_endian>(sym, dynsym_value, shndx,
2313 dynpool, pd);
2317 of->write_output_view(this->offset_, oview_size, psyms);
2318 if (dynamic_view != NULL)
2319 of->write_output_view(this->dynamic_offset_, dynamic_size, dynamic_view);
2322 // Write out the symbol SYM, in section SHNDX, to P. POOL is the
2323 // strtab holding the name.
2325 template<int size, bool big_endian>
2326 void
2327 Symbol_table::sized_write_symbol(
2328 Sized_symbol<size>* sym,
2329 typename elfcpp::Elf_types<size>::Elf_Addr value,
2330 unsigned int shndx,
2331 const Stringpool* pool,
2332 unsigned char* p) const
2334 elfcpp::Sym_write<size, big_endian> osym(p);
2335 osym.put_st_name(pool->get_offset(sym->name()));
2336 osym.put_st_value(value);
2337 osym.put_st_size(sym->symsize());
2338 // A version script may have overridden the default binding.
2339 if (sym->is_forced_local())
2340 osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL, sym->type()));
2341 else
2342 osym.put_st_info(elfcpp::elf_st_info(sym->binding(), sym->type()));
2343 osym.put_st_other(elfcpp::elf_st_other(sym->visibility(), sym->nonvis()));
2344 osym.put_st_shndx(shndx);
2347 // Check for unresolved symbols in shared libraries. This is
2348 // controlled by the --allow-shlib-undefined option.
2350 // We only warn about libraries for which we have seen all the
2351 // DT_NEEDED entries. We don't try to track down DT_NEEDED entries
2352 // which were not seen in this link. If we didn't see a DT_NEEDED
2353 // entry, we aren't going to be able to reliably report whether the
2354 // symbol is undefined.
2356 // We also don't warn about libraries found in the system library
2357 // directory (the directory were we find libc.so); we assume that
2358 // those libraries are OK. This heuristic avoids problems in
2359 // GNU/Linux, in which -ldl can have undefined references satisfied by
2360 // ld-linux.so.
2362 inline void
2363 Symbol_table::warn_about_undefined_dynobj_symbol(
2364 const Input_objects* input_objects,
2365 Symbol* sym) const
2367 bool dummy;
2368 if (sym->source() == Symbol::FROM_OBJECT
2369 && sym->object()->is_dynamic()
2370 && sym->shndx(&dummy) == elfcpp::SHN_UNDEF
2371 && sym->binding() != elfcpp::STB_WEAK
2372 && !parameters->options().allow_shlib_undefined()
2373 && !parameters->target().is_defined_by_abi(sym)
2374 && !input_objects->found_in_system_library_directory(sym->object()))
2376 // A very ugly cast.
2377 Dynobj* dynobj = static_cast<Dynobj*>(sym->object());
2378 if (!dynobj->has_unknown_needed_entries())
2380 if (sym->version())
2381 gold_error(_("%s: undefined reference to '%s', version '%s'"),
2382 sym->object()->name().c_str(),
2383 sym->demangled_name().c_str(),
2384 sym->version());
2385 else
2386 gold_error(_("%s: undefined reference to '%s'"),
2387 sym->object()->name().c_str(),
2388 sym->demangled_name().c_str());
2393 // Write out a section symbol. Return the update offset.
2395 void
2396 Symbol_table::write_section_symbol(const Output_section *os,
2397 Output_symtab_xindex* symtab_xindex,
2398 Output_file* of,
2399 off_t offset) const
2401 switch (parameters->size_and_endianness())
2403 #ifdef HAVE_TARGET_32_LITTLE
2404 case Parameters::TARGET_32_LITTLE:
2405 this->sized_write_section_symbol<32, false>(os, symtab_xindex, of,
2406 offset);
2407 break;
2408 #endif
2409 #ifdef HAVE_TARGET_32_BIG
2410 case Parameters::TARGET_32_BIG:
2411 this->sized_write_section_symbol<32, true>(os, symtab_xindex, of,
2412 offset);
2413 break;
2414 #endif
2415 #ifdef HAVE_TARGET_64_LITTLE
2416 case Parameters::TARGET_64_LITTLE:
2417 this->sized_write_section_symbol<64, false>(os, symtab_xindex, of,
2418 offset);
2419 break;
2420 #endif
2421 #ifdef HAVE_TARGET_64_BIG
2422 case Parameters::TARGET_64_BIG:
2423 this->sized_write_section_symbol<64, true>(os, symtab_xindex, of,
2424 offset);
2425 break;
2426 #endif
2427 default:
2428 gold_unreachable();
2432 // Write out a section symbol, specialized for size and endianness.
2434 template<int size, bool big_endian>
2435 void
2436 Symbol_table::sized_write_section_symbol(const Output_section* os,
2437 Output_symtab_xindex* symtab_xindex,
2438 Output_file* of,
2439 off_t offset) const
2441 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2443 unsigned char* pov = of->get_output_view(offset, sym_size);
2445 elfcpp::Sym_write<size, big_endian> osym(pov);
2446 osym.put_st_name(0);
2447 osym.put_st_value(os->address());
2448 osym.put_st_size(0);
2449 osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL,
2450 elfcpp::STT_SECTION));
2451 osym.put_st_other(elfcpp::elf_st_other(elfcpp::STV_DEFAULT, 0));
2453 unsigned int shndx = os->out_shndx();
2454 if (shndx >= elfcpp::SHN_LORESERVE)
2456 symtab_xindex->add(os->symtab_index(), shndx);
2457 shndx = elfcpp::SHN_XINDEX;
2459 osym.put_st_shndx(shndx);
2461 of->write_output_view(offset, sym_size, pov);
2464 // Print statistical information to stderr. This is used for --stats.
2466 void
2467 Symbol_table::print_stats() const
2469 #if defined(HAVE_TR1_UNORDERED_MAP) || defined(HAVE_EXT_HASH_MAP)
2470 fprintf(stderr, _("%s: symbol table entries: %zu; buckets: %zu\n"),
2471 program_name, this->table_.size(), this->table_.bucket_count());
2472 #else
2473 fprintf(stderr, _("%s: symbol table entries: %zu\n"),
2474 program_name, this->table_.size());
2475 #endif
2476 this->namepool_.print_stats("symbol table stringpool");
2479 // We check for ODR violations by looking for symbols with the same
2480 // name for which the debugging information reports that they were
2481 // defined in different source locations. When comparing the source
2482 // location, we consider instances with the same base filename and
2483 // line number to be the same. This is because different object
2484 // files/shared libraries can include the same header file using
2485 // different paths, and we don't want to report an ODR violation in
2486 // that case.
2488 // This struct is used to compare line information, as returned by
2489 // Dwarf_line_info::one_addr2line. It implements a < comparison
2490 // operator used with std::set.
2492 struct Odr_violation_compare
2494 bool
2495 operator()(const std::string& s1, const std::string& s2) const
2497 std::string::size_type pos1 = s1.rfind('/');
2498 std::string::size_type pos2 = s2.rfind('/');
2499 if (pos1 == std::string::npos
2500 || pos2 == std::string::npos)
2501 return s1 < s2;
2502 return s1.compare(pos1, std::string::npos,
2503 s2, pos2, std::string::npos) < 0;
2507 // Check candidate_odr_violations_ to find symbols with the same name
2508 // but apparently different definitions (different source-file/line-no).
2510 void
2511 Symbol_table::detect_odr_violations(const Task* task,
2512 const char* output_file_name) const
2514 for (Odr_map::const_iterator it = candidate_odr_violations_.begin();
2515 it != candidate_odr_violations_.end();
2516 ++it)
2518 const char* symbol_name = it->first;
2519 // We use a sorted set so the output is deterministic.
2520 std::set<std::string, Odr_violation_compare> line_nums;
2522 for (Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator
2523 locs = it->second.begin();
2524 locs != it->second.end();
2525 ++locs)
2527 // We need to lock the object in order to read it. This
2528 // means that we have to run in a singleton Task. If we
2529 // want to run this in a general Task for better
2530 // performance, we will need one Task for object, plus
2531 // appropriate locking to ensure that we don't conflict with
2532 // other uses of the object. Also note, one_addr2line is not
2533 // currently thread-safe.
2534 Task_lock_obj<Object> tl(task, locs->object);
2535 // 16 is the size of the object-cache that one_addr2line should use.
2536 std::string lineno = Dwarf_line_info::one_addr2line(
2537 locs->object, locs->shndx, locs->offset, 16);
2538 if (!lineno.empty())
2539 line_nums.insert(lineno);
2542 if (line_nums.size() > 1)
2544 gold_warning(_("while linking %s: symbol '%s' defined in multiple "
2545 "places (possible ODR violation):"),
2546 output_file_name, demangle(symbol_name).c_str());
2547 for (std::set<std::string>::const_iterator it2 = line_nums.begin();
2548 it2 != line_nums.end();
2549 ++it2)
2550 fprintf(stderr, " %s\n", it2->c_str());
2553 // We only call one_addr2line() in this function, so we can clear its cache.
2554 Dwarf_line_info::clear_addr2line_cache();
2557 // Warnings functions.
2559 // Add a new warning.
2561 void
2562 Warnings::add_warning(Symbol_table* symtab, const char* name, Object* obj,
2563 const std::string& warning)
2565 name = symtab->canonicalize_name(name);
2566 this->warnings_[name].set(obj, warning);
2569 // Look through the warnings and mark the symbols for which we should
2570 // warn. This is called during Layout::finalize when we know the
2571 // sources for all the symbols.
2573 void
2574 Warnings::note_warnings(Symbol_table* symtab)
2576 for (Warning_table::iterator p = this->warnings_.begin();
2577 p != this->warnings_.end();
2578 ++p)
2580 Symbol* sym = symtab->lookup(p->first, NULL);
2581 if (sym != NULL
2582 && sym->source() == Symbol::FROM_OBJECT
2583 && sym->object() == p->second.object)
2584 sym->set_has_warning();
2588 // Issue a warning. This is called when we see a relocation against a
2589 // symbol for which has a warning.
2591 template<int size, bool big_endian>
2592 void
2593 Warnings::issue_warning(const Symbol* sym,
2594 const Relocate_info<size, big_endian>* relinfo,
2595 size_t relnum, off_t reloffset) const
2597 gold_assert(sym->has_warning());
2598 Warning_table::const_iterator p = this->warnings_.find(sym->name());
2599 gold_assert(p != this->warnings_.end());
2600 gold_warning_at_location(relinfo, relnum, reloffset,
2601 "%s", p->second.text.c_str());
2604 // Instantiate the templates we need. We could use the configure
2605 // script to restrict this to only the ones needed for implemented
2606 // targets.
2608 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
2609 template
2610 void
2611 Sized_symbol<32>::allocate_common(Output_data*, Value_type);
2612 #endif
2614 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
2615 template
2616 void
2617 Sized_symbol<64>::allocate_common(Output_data*, Value_type);
2618 #endif
2620 #ifdef HAVE_TARGET_32_LITTLE
2621 template
2622 void
2623 Symbol_table::add_from_relobj<32, false>(
2624 Sized_relobj<32, false>* relobj,
2625 const unsigned char* syms,
2626 size_t count,
2627 size_t symndx_offset,
2628 const char* sym_names,
2629 size_t sym_name_size,
2630 Sized_relobj<32, true>::Symbols* sympointers);
2631 #endif
2633 #ifdef HAVE_TARGET_32_BIG
2634 template
2635 void
2636 Symbol_table::add_from_relobj<32, true>(
2637 Sized_relobj<32, true>* relobj,
2638 const unsigned char* syms,
2639 size_t count,
2640 size_t symndx_offset,
2641 const char* sym_names,
2642 size_t sym_name_size,
2643 Sized_relobj<32, false>::Symbols* sympointers);
2644 #endif
2646 #ifdef HAVE_TARGET_64_LITTLE
2647 template
2648 void
2649 Symbol_table::add_from_relobj<64, false>(
2650 Sized_relobj<64, false>* relobj,
2651 const unsigned char* syms,
2652 size_t count,
2653 size_t symndx_offset,
2654 const char* sym_names,
2655 size_t sym_name_size,
2656 Sized_relobj<64, true>::Symbols* sympointers);
2657 #endif
2659 #ifdef HAVE_TARGET_64_BIG
2660 template
2661 void
2662 Symbol_table::add_from_relobj<64, true>(
2663 Sized_relobj<64, true>* relobj,
2664 const unsigned char* syms,
2665 size_t count,
2666 size_t symndx_offset,
2667 const char* sym_names,
2668 size_t sym_name_size,
2669 Sized_relobj<64, false>::Symbols* sympointers);
2670 #endif
2672 #ifdef HAVE_TARGET_32_LITTLE
2673 template
2674 void
2675 Symbol_table::add_from_dynobj<32, false>(
2676 Sized_dynobj<32, false>* dynobj,
2677 const unsigned char* syms,
2678 size_t count,
2679 const char* sym_names,
2680 size_t sym_name_size,
2681 const unsigned char* versym,
2682 size_t versym_size,
2683 const std::vector<const char*>* version_map);
2684 #endif
2686 #ifdef HAVE_TARGET_32_BIG
2687 template
2688 void
2689 Symbol_table::add_from_dynobj<32, true>(
2690 Sized_dynobj<32, true>* dynobj,
2691 const unsigned char* syms,
2692 size_t count,
2693 const char* sym_names,
2694 size_t sym_name_size,
2695 const unsigned char* versym,
2696 size_t versym_size,
2697 const std::vector<const char*>* version_map);
2698 #endif
2700 #ifdef HAVE_TARGET_64_LITTLE
2701 template
2702 void
2703 Symbol_table::add_from_dynobj<64, false>(
2704 Sized_dynobj<64, false>* dynobj,
2705 const unsigned char* syms,
2706 size_t count,
2707 const char* sym_names,
2708 size_t sym_name_size,
2709 const unsigned char* versym,
2710 size_t versym_size,
2711 const std::vector<const char*>* version_map);
2712 #endif
2714 #ifdef HAVE_TARGET_64_BIG
2715 template
2716 void
2717 Symbol_table::add_from_dynobj<64, true>(
2718 Sized_dynobj<64, true>* dynobj,
2719 const unsigned char* syms,
2720 size_t count,
2721 const char* sym_names,
2722 size_t sym_name_size,
2723 const unsigned char* versym,
2724 size_t versym_size,
2725 const std::vector<const char*>* version_map);
2726 #endif
2728 #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
2729 template
2730 void
2731 Symbol_table::define_with_copy_reloc<32>(
2732 Sized_symbol<32>* sym,
2733 Output_data* posd,
2734 elfcpp::Elf_types<32>::Elf_Addr value);
2735 #endif
2737 #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
2738 template
2739 void
2740 Symbol_table::define_with_copy_reloc<64>(
2741 Sized_symbol<64>* sym,
2742 Output_data* posd,
2743 elfcpp::Elf_types<64>::Elf_Addr value);
2744 #endif
2746 #ifdef HAVE_TARGET_32_LITTLE
2747 template
2748 void
2749 Warnings::issue_warning<32, false>(const Symbol* sym,
2750 const Relocate_info<32, false>* relinfo,
2751 size_t relnum, off_t reloffset) const;
2752 #endif
2754 #ifdef HAVE_TARGET_32_BIG
2755 template
2756 void
2757 Warnings::issue_warning<32, true>(const Symbol* sym,
2758 const Relocate_info<32, true>* relinfo,
2759 size_t relnum, off_t reloffset) const;
2760 #endif
2762 #ifdef HAVE_TARGET_64_LITTLE
2763 template
2764 void
2765 Warnings::issue_warning<64, false>(const Symbol* sym,
2766 const Relocate_info<64, false>* relinfo,
2767 size_t relnum, off_t reloffset) const;
2768 #endif
2770 #ifdef HAVE_TARGET_64_BIG
2771 template
2772 void
2773 Warnings::issue_warning<64, true>(const Symbol* sym,
2774 const Relocate_info<64, true>* relinfo,
2775 size_t relnum, off_t reloffset) const;
2776 #endif
2778 } // End namespace gold.