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// symtab.cc -- the gold symbol table // Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc. // Written by Ian Lance Taylor <iant@google.com>. // This file is part of gold. // This program is free software; you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation; either version 3 of the License, or // (at your option) any later version. // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // You should have received a copy of the GNU General Public License // along with this program; if not, write to the Free Software // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, // MA 02110-1301, USA. #include "gold.h" #include <cstring> #include <stdint.h> #include <algorithm> #include <set> #include <string> #include <utility> #include "demangle.h" #include "gc.h" #include "object.h" #include "dwarf_reader.h" #include "dynobj.h" #include "output.h" #include "target.h" #include "workqueue.h" #include "symtab.h" #include "script.h" #include "plugin.h" #include "incremental.h" namespace gold { // Class Symbol. // Initialize fields in Symbol. This initializes everything except u_ // and source_. void Symbol::init_fields(const char* name, const char* version, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis) { this->name_ = name; this->version_ = version; this->symtab_index_ = 0; this->dynsym_index_ = 0; this->got_offsets_.init(); this->plt_offset_ = -1U; this->type_ = type; this->binding_ = binding; this->visibility_ = visibility; this->nonvis_ = nonvis; this->is_def_ = false; this->is_forwarder_ = false; this->has_alias_ = false; this->needs_dynsym_entry_ = false; this->in_reg_ = false; this->in_dyn_ = false; this->has_warning_ = false; this->is_copied_from_dynobj_ = false; this->is_forced_local_ = false; this->is_ordinary_shndx_ = false; this->in_real_elf_ = false; this->is_defined_in_discarded_section_ = false; this->undef_binding_set_ = false; this->undef_binding_weak_ = false; } // Return the demangled version of the symbol's name, but only // if the --demangle flag was set. static std::string demangle(const char* name) { if (!parameters->options().do_demangle()) return name; // cplus_demangle allocates memory for the result it returns, // and returns NULL if the name is already demangled. char* demangled_name = cplus_demangle(name, DMGL_ANSI | DMGL_PARAMS); if (demangled_name == NULL) return name; std::string retval(demangled_name); free(demangled_name); return retval; } std::string Symbol::demangled_name() const { return demangle(this->name()); } // Initialize the fields in the base class Symbol for SYM in OBJECT. template<int size, bool big_endian> void Symbol::init_base_object(const char* name, const char* version, Object* object, const elfcpp::Sym<size, big_endian>& sym, unsigned int st_shndx, bool is_ordinary) { this->init_fields(name, version, sym.get_st_type(), sym.get_st_bind(), sym.get_st_visibility(), sym.get_st_nonvis()); this->u_.from_object.object = object; this->u_.from_object.shndx = st_shndx; this->is_ordinary_shndx_ = is_ordinary; this->source_ = FROM_OBJECT; this->in_reg_ = !object->is_dynamic(); this->in_dyn_ = object->is_dynamic(); this->in_real_elf_ = object->pluginobj() == NULL; } // Initialize the fields in the base class Symbol for a symbol defined // in an Output_data. void Symbol::init_base_output_data(const char* name, const char* version, Output_data* od, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis, bool offset_is_from_end) { this->init_fields(name, version, type, binding, visibility, nonvis); this->u_.in_output_data.output_data = od; this->u_.in_output_data.offset_is_from_end = offset_is_from_end; this->source_ = IN_OUTPUT_DATA; this->in_reg_ = true; this->in_real_elf_ = true; } // Initialize the fields in the base class Symbol for a symbol defined // in an Output_segment. void Symbol::init_base_output_segment(const char* name, const char* version, Output_segment* os, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis, Segment_offset_base offset_base) { this->init_fields(name, version, type, binding, visibility, nonvis); this->u_.in_output_segment.output_segment = os; this->u_.in_output_segment.offset_base = offset_base; this->source_ = IN_OUTPUT_SEGMENT; this->in_reg_ = true; this->in_real_elf_ = true; } // Initialize the fields in the base class Symbol for a symbol defined // as a constant. void Symbol::init_base_constant(const char* name, const char* version, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis) { this->init_fields(name, version, type, binding, visibility, nonvis); this->source_ = IS_CONSTANT; this->in_reg_ = true; this->in_real_elf_ = true; } // Initialize the fields in the base class Symbol for an undefined // symbol. void Symbol::init_base_undefined(const char* name, const char* version, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis) { this->init_fields(name, version, type, binding, visibility, nonvis); this->dynsym_index_ = -1U; this->source_ = IS_UNDEFINED; this->in_reg_ = true; this->in_real_elf_ = true; } // Allocate a common symbol in the base. void Symbol::allocate_base_common(Output_data* od) { gold_assert(this->is_common()); this->source_ = IN_OUTPUT_DATA; this->u_.in_output_data.output_data = od; this->u_.in_output_data.offset_is_from_end = false; } // Initialize the fields in Sized_symbol for SYM in OBJECT. template<int size> template<bool big_endian> void Sized_symbol<size>::init_object(const char* name, const char* version, Object* object, const elfcpp::Sym<size, big_endian>& sym, unsigned int st_shndx, bool is_ordinary) { this->init_base_object(name, version, object, sym, st_shndx, is_ordinary); this->value_ = sym.get_st_value(); this->symsize_ = sym.get_st_size(); } // Initialize the fields in Sized_symbol for a symbol defined in an // Output_data. template<int size> void Sized_symbol<size>::init_output_data(const char* name, const char* version, Output_data* od, Value_type value, Size_type symsize, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis, bool offset_is_from_end) { this->init_base_output_data(name, version, od, type, binding, visibility, nonvis, offset_is_from_end); this->value_ = value; this->symsize_ = symsize; } // Initialize the fields in Sized_symbol for a symbol defined in an // Output_segment. template<int size> void Sized_symbol<size>::init_output_segment(const char* name, const char* version, Output_segment* os, Value_type value, Size_type symsize, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis, Segment_offset_base offset_base) { this->init_base_output_segment(name, version, os, type, binding, visibility, nonvis, offset_base); this->value_ = value; this->symsize_ = symsize; } // Initialize the fields in Sized_symbol for a symbol defined as a // constant. template<int size> void Sized_symbol<size>::init_constant(const char* name, const char* version, Value_type value, Size_type symsize, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis) { this->init_base_constant(name, version, type, binding, visibility, nonvis); this->value_ = value; this->symsize_ = symsize; } // Initialize the fields in Sized_symbol for an undefined symbol. template<int size> void Sized_symbol<size>::init_undefined(const char* name, const char* version, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis) { this->init_base_undefined(name, version, type, binding, visibility, nonvis); this->value_ = 0; this->symsize_ = 0; } // Return true if SHNDX represents a common symbol. bool Symbol::is_common_shndx(unsigned int shndx) { return (shndx == elfcpp::SHN_COMMON || shndx == parameters->target().small_common_shndx() || shndx == parameters->target().large_common_shndx()); } // Allocate a common symbol. template<int size> void Sized_symbol<size>::allocate_common(Output_data* od, Value_type value) { this->allocate_base_common(od); this->value_ = value; } // The ""'s around str ensure str is a string literal, so sizeof works. #define strprefix(var, str) (strncmp(var, str, sizeof("" str "") - 1) == 0) // Return true if this symbol should be added to the dynamic symbol // table. inline bool Symbol::should_add_dynsym_entry(Symbol_table* symtab) const { // If the symbol is only present on plugin files, the plugin decided we // don't need it. if (!this->in_real_elf()) return false; // If the symbol is used by a dynamic relocation, we need to add it. if (this->needs_dynsym_entry()) return true; // If this symbol's section is not added, the symbol need not be added. // The section may have been GCed. Note that export_dynamic is being // overridden here. This should not be done for shared objects. if (parameters->options().gc_sections() && !parameters->options().shared() && this->source() == Symbol::FROM_OBJECT && !this->object()->is_dynamic()) { Relobj* relobj = static_cast<Relobj*>(this->object()); bool is_ordinary; unsigned int shndx = this->shndx(&is_ordinary); if (is_ordinary && shndx != elfcpp::SHN_UNDEF && !relobj->is_section_included(shndx) && !symtab->is_section_folded(relobj, shndx)) return false; } // If the symbol was forced local in a version script, do not add it. if (this->is_forced_local()) return false; // If the symbol was forced dynamic in a --dynamic-list file, add it. if (parameters->options().in_dynamic_list(this->name())) return true; // If dynamic-list-data was specified, add any STT_OBJECT. if (parameters->options().dynamic_list_data() && !this->is_from_dynobj() && this->type() == elfcpp::STT_OBJECT) return true; // If --dynamic-list-cpp-new was specified, add any new/delete symbol. // If --dynamic-list-cpp-typeinfo was specified, add any typeinfo symbols. if ((parameters->options().dynamic_list_cpp_new() || parameters->options().dynamic_list_cpp_typeinfo()) && !this->is_from_dynobj()) { // TODO(csilvers): We could probably figure out if we're an operator // new/delete or typeinfo without the need to demangle. char* demangled_name = cplus_demangle(this->name(), DMGL_ANSI | DMGL_PARAMS); if (demangled_name == NULL) { // Not a C++ symbol, so it can't satisfy these flags } else if (parameters->options().dynamic_list_cpp_new() && (strprefix(demangled_name, "operator new") || strprefix(demangled_name, "operator delete"))) { free(demangled_name); return true; } else if (parameters->options().dynamic_list_cpp_typeinfo() && (strprefix(demangled_name, "typeinfo name for") || strprefix(demangled_name, "typeinfo for"))) { free(demangled_name); return true; } else free(demangled_name); } // If exporting all symbols or building a shared library, // and the symbol is defined in a regular object and is // externally visible, we need to add it. if ((parameters->options().export_dynamic() || parameters->options().shared()) && !this->is_from_dynobj() && this->is_externally_visible()) return true; return false; } // Return true if the final value of this symbol is known at link // time. bool Symbol::final_value_is_known() const { // If we are not generating an executable, then no final values are // known, since they will change at runtime. if (parameters->options().output_is_position_independent() || parameters->options().relocatable()) return false; // If the symbol is not from an object file, and is not undefined, // then it is defined, and known. if (this->source_ != FROM_OBJECT) { if (this->source_ != IS_UNDEFINED) return true; } else { // If the symbol is from a dynamic object, then the final value // is not known. if (this->object()->is_dynamic()) return false; // If the symbol is not undefined (it is defined or common), // then the final value is known. if (!this->is_undefined()) return true; } // If the symbol is undefined, then whether the final value is known // depends on whether we are doing a static link. If we are doing a // dynamic link, then the final value could be filled in at runtime. // This could reasonably be the case for a weak undefined symbol. return parameters->doing_static_link(); } // Return the output section where this symbol is defined. Output_section* Symbol::output_section() const { switch (this->source_) { case FROM_OBJECT: { unsigned int shndx = this->u_.from_object.shndx; if (shndx != elfcpp::SHN_UNDEF && this->is_ordinary_shndx_) { gold_assert(!this->u_.from_object.object->is_dynamic()); gold_assert(this->u_.from_object.object->pluginobj() == NULL); Relobj* relobj = static_cast<Relobj*>(this->u_.from_object.object); return relobj->output_section(shndx); } return NULL; } case IN_OUTPUT_DATA: return this->u_.in_output_data.output_data->output_section(); case IN_OUTPUT_SEGMENT: case IS_CONSTANT: case IS_UNDEFINED: return NULL; default: gold_unreachable(); } } // Set the symbol's output section. This is used for symbols defined // in scripts. This should only be called after the symbol table has // been finalized. void Symbol::set_output_section(Output_section* os) { switch (this->source_) { case FROM_OBJECT: case IN_OUTPUT_DATA: gold_assert(this->output_section() == os); break; case IS_CONSTANT: this->source_ = IN_OUTPUT_DATA; this->u_.in_output_data.output_data = os; this->u_.in_output_data.offset_is_from_end = false; break; case IN_OUTPUT_SEGMENT: case IS_UNDEFINED: default: gold_unreachable(); } } // Class Symbol_table. Symbol_table::Symbol_table(unsigned int count, const Version_script_info& version_script) : saw_undefined_(0), offset_(0), table_(count), namepool_(), forwarders_(), commons_(), tls_commons_(), small_commons_(), large_commons_(), forced_locals_(), warnings_(), version_script_(version_script), gc_(NULL), icf_(NULL) { namepool_.reserve(count); } Symbol_table::~Symbol_table() { } // The symbol table key equality function. This is called with // Stringpool keys. inline bool Symbol_table::Symbol_table_eq::operator()(const Symbol_table_key& k1, const Symbol_table_key& k2) const { return k1.first == k2.first && k1.second == k2.second; } bool Symbol_table::is_section_folded(Object* obj, unsigned int shndx) const { return (parameters->options().icf_enabled() && this->icf_->is_section_folded(obj, shndx)); } // For symbols that have been listed with -u option, add them to the // work list to avoid gc'ing them. void Symbol_table::gc_mark_undef_symbols(Layout* layout) { for (options::String_set::const_iterator p = parameters->options().undefined_begin(); p != parameters->options().undefined_end(); ++p) { const char* name = p->c_str(); Symbol* sym = this->lookup(name); gold_assert(sym != NULL); if (sym->source() == Symbol::FROM_OBJECT && !sym->object()->is_dynamic()) { Relobj* obj = static_cast<Relobj*>(sym->object()); bool is_ordinary; unsigned int shndx = sym->shndx(&is_ordinary); if (is_ordinary) { gold_assert(this->gc_ != NULL); this->gc_->worklist().push(Section_id(obj, shndx)); } } } for (Script_options::referenced_const_iterator p = layout->script_options()->referenced_begin(); p != layout->script_options()->referenced_end(); ++p) { Symbol* sym = this->lookup(p->c_str()); gold_assert(sym != NULL); if (sym->source() == Symbol::FROM_OBJECT && !sym->object()->is_dynamic()) { Relobj* obj = static_cast<Relobj*>(sym->object()); bool is_ordinary; unsigned int shndx = sym->shndx(&is_ordinary); if (is_ordinary) { gold_assert(this->gc_ != NULL); this->gc_->worklist().push(Section_id(obj, shndx)); } } } } void Symbol_table::gc_mark_symbol_for_shlib(Symbol* sym) { if (!sym->is_from_dynobj() && sym->is_externally_visible()) { //Add the object and section to the work list. Relobj* obj = static_cast<Relobj*>(sym->object()); bool is_ordinary; unsigned int shndx = sym->shndx(&is_ordinary); if (is_ordinary && shndx != elfcpp::SHN_UNDEF) { gold_assert(this->gc_!= NULL); this->gc_->worklist().push(Section_id(obj, shndx)); } } } // When doing garbage collection, keep symbols that have been seen in // dynamic objects. inline void Symbol_table::gc_mark_dyn_syms(Symbol* sym) { if (sym->in_dyn() && sym->source() == Symbol::FROM_OBJECT && !sym->object()->is_dynamic()) { Relobj* obj = static_cast<Relobj*>(sym->object()); bool is_ordinary; unsigned int shndx = sym->shndx(&is_ordinary); if (is_ordinary && shndx != elfcpp::SHN_UNDEF) { gold_assert(this->gc_ != NULL); this->gc_->worklist().push(Section_id(obj, shndx)); } } } // Make TO a symbol which forwards to FROM. void Symbol_table::make_forwarder(Symbol* from, Symbol* to) { gold_assert(from != to); gold_assert(!from->is_forwarder() && !to->is_forwarder()); this->forwarders_[from] = to; from->set_forwarder(); } // Resolve the forwards from FROM, returning the real symbol. Symbol* Symbol_table::resolve_forwards(const Symbol* from) const { gold_assert(from->is_forwarder()); Unordered_map<const Symbol*, Symbol*>::const_iterator p = this->forwarders_.find(from); gold_assert(p != this->forwarders_.end()); return p->second; } // Look up a symbol by name. Symbol* Symbol_table::lookup(const char* name, const char* version) const { Stringpool::Key name_key; name = this->namepool_.find(name, &name_key); if (name == NULL) return NULL; Stringpool::Key version_key = 0; if (version != NULL) { version = this->namepool_.find(version, &version_key); if (version == NULL) return NULL; } Symbol_table_key key(name_key, version_key); Symbol_table::Symbol_table_type::const_iterator p = this->table_.find(key); if (p == this->table_.end()) return NULL; return p->second; } // Resolve a Symbol with another Symbol. This is only used in the // unusual case where there are references to both an unversioned // symbol and a symbol with a version, and we then discover that that // version is the default version. Because this is unusual, we do // this the slow way, by converting back to an ELF symbol. template<int size, bool big_endian> void Symbol_table::resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from) { unsigned char buf[elfcpp::Elf_sizes<size>::sym_size]; elfcpp::Sym_write<size, big_endian> esym(buf); // We don't bother to set the st_name or the st_shndx field. esym.put_st_value(from->value()); esym.put_st_size(from->symsize()); esym.put_st_info(from->binding(), from->type()); esym.put_st_other(from->visibility(), from->nonvis()); bool is_ordinary; unsigned int shndx = from->shndx(&is_ordinary); this->resolve(to, esym.sym(), shndx, is_ordinary, shndx, from->object(), from->version()); if (from->in_reg()) to->set_in_reg(); if (from->in_dyn()) to->set_in_dyn(); if (parameters->options().gc_sections()) this->gc_mark_dyn_syms(to); } // Record that a symbol is forced to be local by a version script or // by visibility. void Symbol_table::force_local(Symbol* sym) { if (!sym->is_defined() && !sym->is_common()) return; if (sym->is_forced_local()) { // We already got this one. return; } sym->set_is_forced_local(); this->forced_locals_.push_back(sym); } // Adjust NAME for wrapping, and update *NAME_KEY if necessary. This // is only called for undefined symbols, when at least one --wrap // option was used. const char* Symbol_table::wrap_symbol(const char* name, Stringpool::Key* name_key) { // For some targets, we need to ignore a specific character when // wrapping, and add it back later. char prefix = '\0'; if (name[0] == parameters->target().wrap_char()) { prefix = name[0]; ++name; } if (parameters->options().is_wrap(name)) { // Turn NAME into __wrap_NAME. std::string s; if (prefix != '\0') s += prefix; s += "__wrap_"; s += name; // This will give us both the old and new name in NAMEPOOL_, but // that is OK. Only the versions we need will wind up in the // real string table in the output file. return this->namepool_.add(s.c_str(), true, name_key); } const char* const real_prefix = "__real_"; const size_t real_prefix_length = strlen(real_prefix); if (strncmp(name, real_prefix, real_prefix_length) == 0 && parameters->options().is_wrap(name + real_prefix_length)) { // Turn __real_NAME into NAME. std::string s; if (prefix != '\0') s += prefix; s += name + real_prefix_length; return this->namepool_.add(s.c_str(), true, name_key); } return name; } // This is called when we see a symbol NAME/VERSION, and the symbol // already exists in the symbol table, and VERSION is marked as being // the default version. SYM is the NAME/VERSION symbol we just added. // DEFAULT_IS_NEW is true if this is the first time we have seen the // symbol NAME/NULL. PDEF points to the entry for NAME/NULL. template<int size, bool big_endian> void Symbol_table::define_default_version(Sized_symbol<size>* sym, bool default_is_new, Symbol_table_type::iterator pdef) { if (default_is_new) { // This is the first time we have seen NAME/NULL. Make // NAME/NULL point to NAME/VERSION, and mark SYM as the default // version. pdef->second = sym; sym->set_is_default(); } else if (pdef->second == sym) { // NAME/NULL already points to NAME/VERSION. Don't mark the // symbol as the default if it is not already the default. } else { // This is the unfortunate case where we already have entries // for both NAME/VERSION and NAME/NULL. We now see a symbol // NAME/VERSION where VERSION is the default version. We have // already resolved this new symbol with the existing // NAME/VERSION symbol. // It's possible that NAME/NULL and NAME/VERSION are both // defined in regular objects. This can only happen if one // object file defines foo and another defines foo@@ver. This // is somewhat obscure, but we call it a multiple definition // error. // It's possible that NAME/NULL actually has a version, in which // case it won't be the same as VERSION. This happens with // ver_test_7.so in the testsuite for the symbol t2_2. We see // t2_2@@VER2, so we define both t2_2/VER2 and t2_2/NULL. We // then see an unadorned t2_2 in an object file and give it // version VER1 from the version script. This looks like a // default definition for VER1, so it looks like we should merge // t2_2/NULL with t2_2/VER1. That doesn't make sense, but it's // not obvious that this is an error, either. So we just punt. // If one of the symbols has non-default visibility, and the // other is defined in a shared object, then they are different // symbols. // Otherwise, we just resolve the symbols as though they were // the same. if (pdef->second->version() != NULL) gold_assert(pdef->second->version() != sym->version()); else if (sym->visibility() != elfcpp::STV_DEFAULT && pdef->second->is_from_dynobj()) ; else if (pdef->second->visibility() != elfcpp::STV_DEFAULT && sym->is_from_dynobj()) ; else { const Sized_symbol<size>* symdef; symdef = this->get_sized_symbol<size>(pdef->second); Symbol_table::resolve<size, big_endian>(sym, symdef); this->make_forwarder(pdef->second, sym); pdef->second = sym; sym->set_is_default(); } } } // Add one symbol from OBJECT to the symbol table. NAME is symbol // name and VERSION is the version; both are canonicalized. DEF is // whether this is the default version. ST_SHNDX is the symbol's // section index; IS_ORDINARY is whether this is a normal section // rather than a special code. // If IS_DEFAULT_VERSION is true, then this is the definition of a // default version of a symbol. That means that any lookup of // NAME/NULL and any lookup of NAME/VERSION should always return the // same symbol. This is obvious for references, but in particular we // want to do this for definitions: overriding NAME/NULL should also // override NAME/VERSION. If we don't do that, it would be very hard // to override functions in a shared library which uses versioning. // We implement this by simply making both entries in the hash table // point to the same Symbol structure. That is easy enough if this is // the first time we see NAME/NULL or NAME/VERSION, but it is possible // that we have seen both already, in which case they will both have // independent entries in the symbol table. We can't simply change // the symbol table entry, because we have pointers to the entries // attached to the object files. So we mark the entry attached to the // object file as a forwarder, and record it in the forwarders_ map. // Note that entries in the hash table will never be marked as // forwarders. // // ORIG_ST_SHNDX and ST_SHNDX are almost always the same. // ORIG_ST_SHNDX is the section index in the input file, or SHN_UNDEF // for a special section code. ST_SHNDX may be modified if the symbol // is defined in a section being discarded. template<int size, bool big_endian> Sized_symbol<size>* Symbol_table::add_from_object(Object* object, const char* name, Stringpool::Key name_key, const char* version, Stringpool::Key version_key, bool is_default_version, const elfcpp::Sym<size, big_endian>& sym, unsigned int st_shndx, bool is_ordinary, unsigned int orig_st_shndx) { // Print a message if this symbol is being traced. if (parameters->options().is_trace_symbol(name)) { if (orig_st_shndx == elfcpp::SHN_UNDEF) gold_info(_("%s: reference to %s"), object->name().c_str(), name); else gold_info(_("%s: definition of %s"), object->name().c_str(), name); } // For an undefined symbol, we may need to adjust the name using // --wrap. if (orig_st_shndx == elfcpp::SHN_UNDEF && parameters->options().any_wrap()) { const char* wrap_name = this->wrap_symbol(name, &name_key); if (wrap_name != name) { // If we see a reference to malloc with version GLIBC_2.0, // and we turn it into a reference to __wrap_malloc, then we // discard the version number. Otherwise the user would be // required to specify the correct version for // __wrap_malloc. version = NULL; version_key = 0; name = wrap_name; } } Symbol* const snull = NULL; std::pair<typename Symbol_table_type::iterator, bool> ins = this->table_.insert(std::make_pair(std::make_pair(name_key, version_key), snull)); std::pair<typename Symbol_table_type::iterator, bool> insdefault = std::make_pair(this->table_.end(), false); if (is_default_version) { const Stringpool::Key vnull_key = 0; insdefault = this->table_.insert(std::make_pair(std::make_pair(name_key, vnull_key), snull)); } // ins.first: an iterator, which is a pointer to a pair. // ins.first->first: the key (a pair of name and version). // ins.first->second: the value (Symbol*). // ins.second: true if new entry was inserted, false if not. Sized_symbol<size>* ret; bool was_undefined; bool was_common; if (!ins.second) { // We already have an entry for NAME/VERSION. ret = this->get_sized_symbol<size>(ins.first->second); gold_assert(ret != NULL); was_undefined = ret->is_undefined(); was_common = ret->is_common(); this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object, version); if (parameters->options().gc_sections()) this->gc_mark_dyn_syms(ret); if (is_default_version) this->define_default_version<size, big_endian>(ret, insdefault.second, insdefault.first); } else { // This is the first time we have seen NAME/VERSION. gold_assert(ins.first->second == NULL); if (is_default_version && !insdefault.second) { // We already have an entry for NAME/NULL. If we override // it, then change it to NAME/VERSION. ret = this->get_sized_symbol<size>(insdefault.first->second); was_undefined = ret->is_undefined(); was_common = ret->is_common(); this->resolve(ret, sym, st_shndx, is_ordinary, orig_st_shndx, object, version); if (parameters->options().gc_sections()) this->gc_mark_dyn_syms(ret); ins.first->second = ret; } else { was_undefined = false; was_common = false; Sized_target<size, big_endian>* target = parameters->sized_target<size, big_endian>(); if (!target->has_make_symbol()) ret = new Sized_symbol<size>(); else { ret = target->make_symbol(); if (ret == NULL) { // This means that we don't want a symbol table // entry after all. if (!is_default_version) this->table_.erase(ins.first); else { this->table_.erase(insdefault.first); // Inserting INSDEFAULT invalidated INS. this->table_.erase(std::make_pair(name_key, version_key)); } return NULL; } } ret->init_object(name, version, object, sym, st_shndx, is_ordinary); ins.first->second = ret; if (is_default_version) { // This is the first time we have seen NAME/NULL. Point // it at the new entry for NAME/VERSION. gold_assert(insdefault.second); insdefault.first->second = ret; } } if (is_default_version) ret->set_is_default(); } // Record every time we see a new undefined symbol, to speed up // archive groups. if (!was_undefined && ret->is_undefined()) { ++this->saw_undefined_; if (parameters->options().has_plugins()) parameters->options().plugins()->new_undefined_symbol(ret); } // Keep track of common symbols, to speed up common symbol // allocation. if (!was_common && ret->is_common()) { if (ret->type() == elfcpp::STT_TLS) this->tls_commons_.push_back(ret); else if (!is_ordinary && st_shndx == parameters->target().small_common_shndx()) this->small_commons_.push_back(ret); else if (!is_ordinary && st_shndx == parameters->target().large_common_shndx()) this->large_commons_.push_back(ret); else this->commons_.push_back(ret); } // If we're not doing a relocatable link, then any symbol with // hidden or internal visibility is local. if ((ret->visibility() == elfcpp::STV_HIDDEN || ret->visibility() == elfcpp::STV_INTERNAL) && (ret->binding() == elfcpp::STB_GLOBAL || ret->binding() == elfcpp::STB_GNU_UNIQUE || ret->binding() == elfcpp::STB_WEAK) && !parameters->options().relocatable()) this->force_local(ret); return ret; } // Add all the symbols in a relocatable object to the hash table. template<int size, bool big_endian> void Symbol_table::add_from_relobj( Sized_relobj_file<size, big_endian>* relobj, const unsigned char* syms, size_t count, size_t symndx_offset, const char* sym_names, size_t sym_name_size, typename Sized_relobj_file<size, big_endian>::Symbols* sympointers, size_t* defined) { *defined = 0; gold_assert(size == parameters->target().get_size()); const int sym_size = elfcpp::Elf_sizes<size>::sym_size; const bool just_symbols = relobj->just_symbols(); const unsigned char* p = syms; for (size_t i = 0; i < count; ++i, p += sym_size) { (*sympointers)[i] = NULL; elfcpp::Sym<size, big_endian> sym(p); unsigned int st_name = sym.get_st_name(); if (st_name >= sym_name_size) { relobj->error(_("bad global symbol name offset %u at %zu"), st_name, i); continue; } const char* name = sym_names + st_name; bool is_ordinary; unsigned int st_shndx = relobj->adjust_sym_shndx(i + symndx_offset, sym.get_st_shndx(), &is_ordinary); unsigned int orig_st_shndx = st_shndx; if (!is_ordinary) orig_st_shndx = elfcpp::SHN_UNDEF; if (st_shndx != elfcpp::SHN_UNDEF) ++*defined; // A symbol defined in a section which we are not including must // be treated as an undefined symbol. bool is_defined_in_discarded_section = false; if (st_shndx != elfcpp::SHN_UNDEF && is_ordinary && !relobj->is_section_included(st_shndx) && !this->is_section_folded(relobj, st_shndx)) { st_shndx = elfcpp::SHN_UNDEF; is_defined_in_discarded_section = true; } // In an object file, an '@' in the name separates the symbol // name from the version name. If there are two '@' characters, // this is the default version. const char* ver = strchr(name, '@'); Stringpool::Key ver_key = 0; int namelen = 0; // IS_DEFAULT_VERSION: is the version default? // IS_FORCED_LOCAL: is the symbol forced local? bool is_default_version = false; bool is_forced_local = false; if (ver != NULL) { // The symbol name is of the form foo@VERSION or foo@@VERSION namelen = ver - name; ++ver; if (*ver == '@') { is_default_version = true; ++ver; } ver = this->namepool_.add(ver, true, &ver_key); } // We don't want to assign a version to an undefined symbol, // even if it is listed in the version script. FIXME: What // about a common symbol? else { namelen = strlen(name); if (!this->version_script_.empty() && st_shndx != elfcpp::SHN_UNDEF) { // The symbol name did not have a version, but the // version script may assign a version anyway. std::string version; bool is_global; if (this->version_script_.get_symbol_version(name, &version, &is_global)) { if (!is_global) is_forced_local = true; else if (!version.empty()) { ver = this->namepool_.add_with_length(version.c_str(), version.length(), true, &ver_key); is_default_version = true; } } } } elfcpp::Sym<size, big_endian>* psym = &sym; unsigned char symbuf[sym_size]; elfcpp::Sym<size, big_endian> sym2(symbuf); if (just_symbols) { memcpy(symbuf, p, sym_size); elfcpp::Sym_write<size, big_endian> sw(symbuf); if (orig_st_shndx != elfcpp::SHN_UNDEF && is_ordinary) { // Symbol values in object files are section relative. // This is normally what we want, but since here we are // converting the symbol to absolute we need to add the // section address. The section address in an object // file is normally zero, but people can use a linker // script to change it. sw.put_st_value(sym.get_st_value() + relobj->section_address(orig_st_shndx)); } st_shndx = elfcpp::SHN_ABS; is_ordinary = false; psym = &sym2; } // Fix up visibility if object has no-export set. if (relobj->no_export() && (orig_st_shndx != elfcpp::SHN_UNDEF || !is_ordinary)) { // We may have copied symbol already above. if (psym != &sym2) { memcpy(symbuf, p, sym_size); psym = &sym2; } elfcpp::STV visibility = sym2.get_st_visibility(); if (visibility == elfcpp::STV_DEFAULT || visibility == elfcpp::STV_PROTECTED) { elfcpp::Sym_write<size, big_endian> sw(symbuf); unsigned char nonvis = sym2.get_st_nonvis(); sw.put_st_other(elfcpp::STV_HIDDEN, nonvis); } } Stringpool::Key name_key; name = this->namepool_.add_with_length(name, namelen, true, &name_key); Sized_symbol<size>* res; res = this->add_from_object(relobj, name, name_key, ver, ver_key, is_default_version, *psym, st_shndx, is_ordinary, orig_st_shndx); // If building a shared library using garbage collection, do not // treat externally visible symbols as garbage. if (parameters->options().gc_sections() && parameters->options().shared()) this->gc_mark_symbol_for_shlib(res); if (is_forced_local) this->force_local(res); if (is_defined_in_discarded_section) res->set_is_defined_in_discarded_section(); (*sympointers)[i] = res; } } // Add a symbol from a plugin-claimed file. template<int size, bool big_endian> Symbol* Symbol_table::add_from_pluginobj( Sized_pluginobj<size, big_endian>* obj, const char* name, const char* ver, elfcpp::Sym<size, big_endian>* sym) { unsigned int st_shndx = sym->get_st_shndx(); bool is_ordinary = st_shndx < elfcpp::SHN_LORESERVE; Stringpool::Key ver_key = 0; bool is_default_version = false; bool is_forced_local = false; if (ver != NULL) { ver = this->namepool_.add(ver, true, &ver_key); } // We don't want to assign a version to an undefined symbol, // even if it is listed in the version script. FIXME: What // about a common symbol? else { if (!this->version_script_.empty() && st_shndx != elfcpp::SHN_UNDEF) { // The symbol name did not have a version, but the // version script may assign a version anyway. std::string version; bool is_global; if (this->version_script_.get_symbol_version(name, &version, &is_global)) { if (!is_global) is_forced_local = true; else if (!version.empty()) { ver = this->namepool_.add_with_length(version.c_str(), version.length(), true, &ver_key); is_default_version = true; } } } } Stringpool::Key name_key; name = this->namepool_.add(name, true, &name_key); Sized_symbol<size>* res; res = this->add_from_object(obj, name, name_key, ver, ver_key, is_default_version, *sym, st_shndx, is_ordinary, st_shndx); if (is_forced_local) this->force_local(res); return res; } // Add all the symbols in a dynamic object to the hash table. template<int size, bool big_endian> void Symbol_table::add_from_dynobj( Sized_dynobj<size, big_endian>* dynobj, const unsigned char* syms, size_t count, const char* sym_names, size_t sym_name_size, const unsigned char* versym, size_t versym_size, const std::vector<const char*>* version_map, typename Sized_relobj_file<size, big_endian>::Symbols* sympointers, size_t* defined) { *defined = 0; gold_assert(size == parameters->target().get_size()); if (dynobj->just_symbols()) { gold_error(_("--just-symbols does not make sense with a shared object")); return; } if (versym != NULL && versym_size / 2 < count) { dynobj->error(_("too few symbol versions")); return; } const int sym_size = elfcpp::Elf_sizes<size>::sym_size; // We keep a list of all STT_OBJECT symbols, so that we can resolve // weak aliases. This is necessary because if the dynamic object // provides the same variable under two names, one of which is a // weak definition, and the regular object refers to the weak // definition, we have to put both the weak definition and the // strong definition into the dynamic symbol table. Given a weak // definition, the only way that we can find the corresponding // strong definition, if any, is to search the symbol table. std::vector<Sized_symbol<size>*> object_symbols; const unsigned char* p = syms; const unsigned char* vs = versym; for (size_t i = 0; i < count; ++i, p += sym_size, vs += 2) { elfcpp::Sym<size, big_endian> sym(p); if (sympointers != NULL) (*sympointers)[i] = NULL; // Ignore symbols with local binding or that have // internal or hidden visibility. if (sym.get_st_bind() == elfcpp::STB_LOCAL || sym.get_st_visibility() == elfcpp::STV_INTERNAL || sym.get_st_visibility() == elfcpp::STV_HIDDEN) continue; // A protected symbol in a shared library must be treated as a // normal symbol when viewed from outside the shared library. // Implement this by overriding the visibility here. elfcpp::Sym<size, big_endian>* psym = &sym; unsigned char symbuf[sym_size]; elfcpp::Sym<size, big_endian> sym2(symbuf); if (sym.get_st_visibility() == elfcpp::STV_PROTECTED) { memcpy(symbuf, p, sym_size); elfcpp::Sym_write<size, big_endian> sw(symbuf); sw.put_st_other(elfcpp::STV_DEFAULT, sym.get_st_nonvis()); psym = &sym2; } unsigned int st_name = psym->get_st_name(); if (st_name >= sym_name_size) { dynobj->error(_("bad symbol name offset %u at %zu"), st_name, i); continue; } const char* name = sym_names + st_name; bool is_ordinary; unsigned int st_shndx = dynobj->adjust_sym_shndx(i, psym->get_st_shndx(), &is_ordinary); if (st_shndx != elfcpp::SHN_UNDEF) ++*defined; Sized_symbol<size>* res; if (versym == NULL) { Stringpool::Key name_key; name = this->namepool_.add(name, true, &name_key); res = this->add_from_object(dynobj, name, name_key, NULL, 0, false, *psym, st_shndx, is_ordinary, st_shndx); } else { // Read the version information. unsigned int v = elfcpp::Swap<16, big_endian>::readval(vs); bool hidden = (v & elfcpp::VERSYM_HIDDEN) != 0; v &= elfcpp::VERSYM_VERSION; // The Sun documentation says that V can be VER_NDX_LOCAL, // or VER_NDX_GLOBAL, or a version index. The meaning of // VER_NDX_LOCAL is defined as "Symbol has local scope." // The old GNU linker will happily generate VER_NDX_LOCAL // for an undefined symbol. I don't know what the Sun // linker will generate. if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL) && st_shndx != elfcpp::SHN_UNDEF) { // This symbol should not be visible outside the object. continue; } // At this point we are definitely going to add this symbol. Stringpool::Key name_key; name = this->namepool_.add(name, true, &name_key); if (v == static_cast<unsigned int>(elfcpp::VER_NDX_LOCAL) || v == static_cast<unsigned int>(elfcpp::VER_NDX_GLOBAL)) { // This symbol does not have a version. res = this->add_from_object(dynobj, name, name_key, NULL, 0, false, *psym, st_shndx, is_ordinary, st_shndx); } else { if (v >= version_map->size()) { dynobj->error(_("versym for symbol %zu out of range: %u"), i, v); continue; } const char* version = (*version_map)[v]; if (version == NULL) { dynobj->error(_("versym for symbol %zu has no name: %u"), i, v); continue; } Stringpool::Key version_key; version = this->namepool_.add(version, true, &version_key); // If this is an absolute symbol, and the version name // and symbol name are the same, then this is the // version definition symbol. These symbols exist to // support using -u to pull in particular versions. We // do not want to record a version for them. if (st_shndx == elfcpp::SHN_ABS && !is_ordinary && name_key == version_key) res = this->add_from_object(dynobj, name, name_key, NULL, 0, false, *psym, st_shndx, is_ordinary, st_shndx); else { const bool is_default_version = !hidden && st_shndx != elfcpp::SHN_UNDEF; res = this->add_from_object(dynobj, name, name_key, version, version_key, is_default_version, *psym, st_shndx, is_ordinary, st_shndx); } } } // Note that it is possible that RES was overridden by an // earlier object, in which case it can't be aliased here. if (st_shndx != elfcpp::SHN_UNDEF && is_ordinary && psym->get_st_type() == elfcpp::STT_OBJECT && res->source() == Symbol::FROM_OBJECT && res->object() == dynobj) object_symbols.push_back(res); if (sympointers != NULL) (*sympointers)[i] = res; } this->record_weak_aliases(&object_symbols); } // Add a symbol from a incremental object file. template<int size, bool big_endian> Symbol* Symbol_table::add_from_incrobj( Object* obj, const char* name, const char* ver, elfcpp::Sym<size, big_endian>* sym) { unsigned int st_shndx = sym->get_st_shndx(); bool is_ordinary = st_shndx < elfcpp::SHN_LORESERVE; Stringpool::Key ver_key = 0; bool is_default_version = false; bool is_forced_local = false; Stringpool::Key name_key; name = this->namepool_.add(name, true, &name_key); Sized_symbol<size>* res; res = this->add_from_object(obj, name, name_key, ver, ver_key, is_default_version, *sym, st_shndx, is_ordinary, st_shndx); if (is_forced_local) this->force_local(res); return res; } // This is used to sort weak aliases. We sort them first by section // index, then by offset, then by weak ahead of strong. template<int size> class Weak_alias_sorter { public: bool operator()(const Sized_symbol<size>*, const Sized_symbol<size>*) const; }; template<int size> bool Weak_alias_sorter<size>::operator()(const Sized_symbol<size>* s1, const Sized_symbol<size>* s2) const { bool is_ordinary; unsigned int s1_shndx = s1->shndx(&is_ordinary); gold_assert(is_ordinary); unsigned int s2_shndx = s2->shndx(&is_ordinary); gold_assert(is_ordinary); if (s1_shndx != s2_shndx) return s1_shndx < s2_shndx; if (s1->value() != s2->value()) return s1->value() < s2->value(); if (s1->binding() != s2->binding()) { if (s1->binding() == elfcpp::STB_WEAK) return true; if (s2->binding() == elfcpp::STB_WEAK) return false; } return std::string(s1->name()) < std::string(s2->name()); } // SYMBOLS is a list of object symbols from a dynamic object. Look // for any weak aliases, and record them so that if we add the weak // alias to the dynamic symbol table, we also add the corresponding // strong symbol. template<int size> void Symbol_table::record_weak_aliases(std::vector<Sized_symbol<size>*>* symbols) { // Sort the vector by section index, then by offset, then by weak // ahead of strong. std::sort(symbols->begin(), symbols->end(), Weak_alias_sorter<size>()); // Walk through the vector. For each weak definition, record // aliases. for (typename std::vector<Sized_symbol<size>*>::const_iterator p = symbols->begin(); p != symbols->end(); ++p) { if ((*p)->binding() != elfcpp::STB_WEAK) continue; // Build a circular list of weak aliases. Each symbol points to // the next one in the circular list. Sized_symbol<size>* from_sym = *p; typename std::vector<Sized_symbol<size>*>::const_iterator q; for (q = p + 1; q != symbols->end(); ++q) { bool dummy; if ((*q)->shndx(&dummy) != from_sym->shndx(&dummy) || (*q)->value() != from_sym->value()) break; this->weak_aliases_[from_sym] = *q; from_sym->set_has_alias(); from_sym = *q; } if (from_sym != *p) { this->weak_aliases_[from_sym] = *p; from_sym->set_has_alias(); } p = q - 1; } } // Create and return a specially defined symbol. If ONLY_IF_REF is // true, then only create the symbol if there is a reference to it. // If this does not return NULL, it sets *POLDSYM to the existing // symbol if there is one. This sets *RESOLVE_OLDSYM if we should // resolve the newly created symbol to the old one. This // canonicalizes *PNAME and *PVERSION. template<int size, bool big_endian> Sized_symbol<size>* Symbol_table::define_special_symbol(const char** pname, const char** pversion, bool only_if_ref, Sized_symbol<size>** poldsym, bool* resolve_oldsym) { *resolve_oldsym = false; // If the caller didn't give us a version, see if we get one from // the version script. std::string v; bool is_default_version = false; if (*pversion == NULL) { bool is_global; if (this->version_script_.get_symbol_version(*pname, &v, &is_global)) { if (is_global && !v.empty()) { *pversion = v.c_str(); // If we get the version from a version script, then we // are also the default version. is_default_version = true; } } } Symbol* oldsym; Sized_symbol<size>* sym; bool add_to_table = false; typename Symbol_table_type::iterator add_loc = this->table_.end(); bool add_def_to_table = false; typename Symbol_table_type::iterator add_def_loc = this->table_.end(); if (only_if_ref) { oldsym = this->lookup(*pname, *pversion); if (oldsym == NULL && is_default_version) oldsym = this->lookup(*pname, NULL); if (oldsym == NULL || !oldsym->is_undefined()) return NULL; *pname = oldsym->name(); if (!is_default_version) *pversion = oldsym->version(); } else { // Canonicalize NAME and VERSION. Stringpool::Key name_key; *pname = this->namepool_.add(*pname, true, &name_key); Stringpool::Key version_key = 0; if (*pversion != NULL) *pversion = this->namepool_.add(*pversion, true, &version_key); Symbol* const snull = NULL; std::pair<typename Symbol_table_type::iterator, bool> ins = this->table_.insert(std::make_pair(std::make_pair(name_key, version_key), snull)); std::pair<typename Symbol_table_type::iterator, bool> insdefault = std::make_pair(this->table_.end(), false); if (is_default_version) { const Stringpool::Key vnull = 0; insdefault = this->table_.insert(std::make_pair(std::make_pair(name_key, vnull), snull)); } if (!ins.second) { // We already have a symbol table entry for NAME/VERSION. oldsym = ins.first->second; gold_assert(oldsym != NULL); if (is_default_version) { Sized_symbol<size>* soldsym = this->get_sized_symbol<size>(oldsym); this->define_default_version<size, big_endian>(soldsym, insdefault.second, insdefault.first); } } else { // We haven't seen this symbol before. gold_assert(ins.first->second == NULL); add_to_table = true; add_loc = ins.first; if (is_default_version && !insdefault.second) { // We are adding NAME/VERSION, and it is the default // version. We already have an entry for NAME/NULL. oldsym = insdefault.first->second; *resolve_oldsym = true; } else { oldsym = NULL; if (is_default_version) { add_def_to_table = true; add_def_loc = insdefault.first; } } } } const Target& target = parameters->target(); if (!target.has_make_symbol()) sym = new Sized_symbol<size>(); else { Sized_target<size, big_endian>* sized_target = parameters->sized_target<size, big_endian>(); sym = sized_target->make_symbol(); if (sym == NULL) return NULL; } if (add_to_table) add_loc->second = sym; else gold_assert(oldsym != NULL); if (add_def_to_table) add_def_loc->second = sym; *poldsym = this->get_sized_symbol<size>(oldsym); return sym; } // Define a symbol based on an Output_data. Symbol* Symbol_table::define_in_output_data(const char* name, const char* version, Defined defined, Output_data* od, uint64_t value, uint64_t symsize, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis, bool offset_is_from_end, bool only_if_ref) { if (parameters->target().get_size() == 32) { #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) return this->do_define_in_output_data<32>(name, version, defined, od, value, symsize, type, binding, visibility, nonvis, offset_is_from_end, only_if_ref); #else gold_unreachable(); #endif } else if (parameters->target().get_size() == 64) { #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) return this->do_define_in_output_data<64>(name, version, defined, od, value, symsize, type, binding, visibility, nonvis, offset_is_from_end, only_if_ref); #else gold_unreachable(); #endif } else gold_unreachable(); } // Define a symbol in an Output_data, sized version. template<int size> Sized_symbol<size>* Symbol_table::do_define_in_output_data( const char* name, const char* version, Defined defined, Output_data* od, typename elfcpp::Elf_types<size>::Elf_Addr value, typename elfcpp::Elf_types<size>::Elf_WXword symsize, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis, bool offset_is_from_end, bool only_if_ref) { Sized_symbol<size>* sym; Sized_symbol<size>* oldsym; bool resolve_oldsym; if (parameters->target().is_big_endian()) { #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG) sym = this->define_special_symbol<size, true>(&name, &version, only_if_ref, &oldsym, &resolve_oldsym); #else gold_unreachable(); #endif } else { #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE) sym = this->define_special_symbol<size, false>(&name, &version, only_if_ref, &oldsym, &resolve_oldsym); #else gold_unreachable(); #endif } if (sym == NULL) return NULL; sym->init_output_data(name, version, od, value, symsize, type, binding, visibility, nonvis, offset_is_from_end); if (oldsym == NULL) { if (binding == elfcpp::STB_LOCAL || this->version_script_.symbol_is_local(name)) this->force_local(sym); else if (version != NULL) sym->set_is_default(); return sym; } if (Symbol_table::should_override_with_special(oldsym, defined)) this->override_with_special(oldsym, sym); if (resolve_oldsym) return sym; else { delete sym; return oldsym; } } // Define a symbol based on an Output_segment. Symbol* Symbol_table::define_in_output_segment(const char* name, const char* version, Defined defined, Output_segment* os, uint64_t value, uint64_t symsize, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis, Symbol::Segment_offset_base offset_base, bool only_if_ref) { if (parameters->target().get_size() == 32) { #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) return this->do_define_in_output_segment<32>(name, version, defined, os, value, symsize, type, binding, visibility, nonvis, offset_base, only_if_ref); #else gold_unreachable(); #endif } else if (parameters->target().get_size() == 64) { #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) return this->do_define_in_output_segment<64>(name, version, defined, os, value, symsize, type, binding, visibility, nonvis, offset_base, only_if_ref); #else gold_unreachable(); #endif } else gold_unreachable(); } // Define a symbol in an Output_segment, sized version. template<int size> Sized_symbol<size>* Symbol_table::do_define_in_output_segment( const char* name, const char* version, Defined defined, Output_segment* os, typename elfcpp::Elf_types<size>::Elf_Addr value, typename elfcpp::Elf_types<size>::Elf_WXword symsize, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis, Symbol::Segment_offset_base offset_base, bool only_if_ref) { Sized_symbol<size>* sym; Sized_symbol<size>* oldsym; bool resolve_oldsym; if (parameters->target().is_big_endian()) { #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG) sym = this->define_special_symbol<size, true>(&name, &version, only_if_ref, &oldsym, &resolve_oldsym); #else gold_unreachable(); #endif } else { #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE) sym = this->define_special_symbol<size, false>(&name, &version, only_if_ref, &oldsym, &resolve_oldsym); #else gold_unreachable(); #endif } if (sym == NULL) return NULL; sym->init_output_segment(name, version, os, value, symsize, type, binding, visibility, nonvis, offset_base); if (oldsym == NULL) { if (binding == elfcpp::STB_LOCAL || this->version_script_.symbol_is_local(name)) this->force_local(sym); else if (version != NULL) sym->set_is_default(); return sym; } if (Symbol_table::should_override_with_special(oldsym, defined)) this->override_with_special(oldsym, sym); if (resolve_oldsym) return sym; else { delete sym; return oldsym; } } // Define a special symbol with a constant value. It is a multiple // definition error if this symbol is already defined. Symbol* Symbol_table::define_as_constant(const char* name, const char* version, Defined defined, uint64_t value, uint64_t symsize, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis, bool only_if_ref, bool force_override) { if (parameters->target().get_size() == 32) { #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) return this->do_define_as_constant<32>(name, version, defined, value, symsize, type, binding, visibility, nonvis, only_if_ref, force_override); #else gold_unreachable(); #endif } else if (parameters->target().get_size() == 64) { #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) return this->do_define_as_constant<64>(name, version, defined, value, symsize, type, binding, visibility, nonvis, only_if_ref, force_override); #else gold_unreachable(); #endif } else gold_unreachable(); } // Define a symbol as a constant, sized version. template<int size> Sized_symbol<size>* Symbol_table::do_define_as_constant( const char* name, const char* version, Defined defined, typename elfcpp::Elf_types<size>::Elf_Addr value, typename elfcpp::Elf_types<size>::Elf_WXword symsize, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis, bool only_if_ref, bool force_override) { Sized_symbol<size>* sym; Sized_symbol<size>* oldsym; bool resolve_oldsym; if (parameters->target().is_big_endian()) { #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG) sym = this->define_special_symbol<size, true>(&name, &version, only_if_ref, &oldsym, &resolve_oldsym); #else gold_unreachable(); #endif } else { #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE) sym = this->define_special_symbol<size, false>(&name, &version, only_if_ref, &oldsym, &resolve_oldsym); #else gold_unreachable(); #endif } if (sym == NULL) return NULL; sym->init_constant(name, version, value, symsize, type, binding, visibility, nonvis); if (oldsym == NULL) { // Version symbols are absolute symbols with name == version. // We don't want to force them to be local. if ((version == NULL || name != version || value != 0) && (binding == elfcpp::STB_LOCAL || this->version_script_.symbol_is_local(name))) this->force_local(sym); else if (version != NULL && (name != version || value != 0)) sym->set_is_default(); return sym; } if (force_override || Symbol_table::should_override_with_special(oldsym, defined)) this->override_with_special(oldsym, sym); if (resolve_oldsym) return sym; else { delete sym; return oldsym; } } // Define a set of symbols in output sections. void Symbol_table::define_symbols(const Layout* layout, int count, const Define_symbol_in_section* p, bool only_if_ref) { for (int i = 0; i < count; ++i, ++p) { Output_section* os = layout->find_output_section(p->output_section); if (os != NULL) this->define_in_output_data(p->name, NULL, PREDEFINED, os, p->value, p->size, p->type, p->binding, p->visibility, p->nonvis, p->offset_is_from_end, only_if_ref || p->only_if_ref); else this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size, p->type, p->binding, p->visibility, p->nonvis, only_if_ref || p->only_if_ref, false); } } // Define a set of symbols in output segments. void Symbol_table::define_symbols(const Layout* layout, int count, const Define_symbol_in_segment* p, bool only_if_ref) { for (int i = 0; i < count; ++i, ++p) { Output_segment* os = layout->find_output_segment(p->segment_type, p->segment_flags_set, p->segment_flags_clear); if (os != NULL) this->define_in_output_segment(p->name, NULL, PREDEFINED, os, p->value, p->size, p->type, p->binding, p->visibility, p->nonvis, p->offset_base, only_if_ref || p->only_if_ref); else this->define_as_constant(p->name, NULL, PREDEFINED, 0, p->size, p->type, p->binding, p->visibility, p->nonvis, only_if_ref || p->only_if_ref, false); } } // Define CSYM using a COPY reloc. POSD is the Output_data where the // symbol should be defined--typically a .dyn.bss section. VALUE is // the offset within POSD. template<int size> void Symbol_table::define_with_copy_reloc( Sized_symbol<size>* csym, Output_data* posd, typename elfcpp::Elf_types<size>::Elf_Addr value) { gold_assert(csym->is_from_dynobj()); gold_assert(!csym->is_copied_from_dynobj()); Object* object = csym->object(); gold_assert(object->is_dynamic()); Dynobj* dynobj = static_cast<Dynobj*>(object); // Our copied variable has to override any variable in a shared // library. elfcpp::STB binding = csym->binding(); if (binding == elfcpp::STB_WEAK) binding = elfcpp::STB_GLOBAL; this->define_in_output_data(csym->name(), csym->version(), COPY, posd, value, csym->symsize(), csym->type(), binding, csym->visibility(), csym->nonvis(), false, false); csym->set_is_copied_from_dynobj(); csym->set_needs_dynsym_entry(); this->copied_symbol_dynobjs_[csym] = dynobj; // We have now defined all aliases, but we have not entered them all // in the copied_symbol_dynobjs_ map. if (csym->has_alias()) { Symbol* sym = csym; while (true) { sym = this->weak_aliases_[sym]; if (sym == csym) break; gold_assert(sym->output_data() == posd); sym->set_is_copied_from_dynobj(); this->copied_symbol_dynobjs_[sym] = dynobj; } } } // SYM is defined using a COPY reloc. Return the dynamic object where // the original definition was found. Dynobj* Symbol_table::get_copy_source(const Symbol* sym) const { gold_assert(sym->is_copied_from_dynobj()); Copied_symbol_dynobjs::const_iterator p = this->copied_symbol_dynobjs_.find(sym); gold_assert(p != this->copied_symbol_dynobjs_.end()); return p->second; } // Add any undefined symbols named on the command line. void Symbol_table::add_undefined_symbols_from_command_line(Layout* layout) { if (parameters->options().any_undefined() || layout->script_options()->any_unreferenced()) { if (parameters->target().get_size() == 32) { #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) this->do_add_undefined_symbols_from_command_line<32>(layout); #else gold_unreachable(); #endif } else if (parameters->target().get_size() == 64) { #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) this->do_add_undefined_symbols_from_command_line<64>(layout); #else gold_unreachable(); #endif } else gold_unreachable(); } } template<int size> void Symbol_table::do_add_undefined_symbols_from_command_line(Layout* layout) { for (options::String_set::const_iterator p = parameters->options().undefined_begin(); p != parameters->options().undefined_end(); ++p) this->add_undefined_symbol_from_command_line<size>(p->c_str()); for (Script_options::referenced_const_iterator p = layout->script_options()->referenced_begin(); p != layout->script_options()->referenced_end(); ++p) this->add_undefined_symbol_from_command_line<size>(p->c_str()); } template<int size> void Symbol_table::add_undefined_symbol_from_command_line(const char* name) { if (this->lookup(name) != NULL) return; const char* version = NULL; Sized_symbol<size>* sym; Sized_symbol<size>* oldsym; bool resolve_oldsym; if (parameters->target().is_big_endian()) { #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG) sym = this->define_special_symbol<size, true>(&name, &version, false, &oldsym, &resolve_oldsym); #else gold_unreachable(); #endif } else { #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE) sym = this->define_special_symbol<size, false>(&name, &version, false, &oldsym, &resolve_oldsym); #else gold_unreachable(); #endif } gold_assert(oldsym == NULL); sym->init_undefined(name, version, elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL, elfcpp::STV_DEFAULT, 0); ++this->saw_undefined_; } // Set the dynamic symbol indexes. INDEX is the index of the first // global dynamic symbol. Pointers to the symbols are stored into the // vector SYMS. The names are added to DYNPOOL. This returns an // updated dynamic symbol index. unsigned int Symbol_table::set_dynsym_indexes(unsigned int index, std::vector<Symbol*>* syms, Stringpool* dynpool, Versions* versions) { for (Symbol_table_type::iterator p = this->table_.begin(); p != this->table_.end(); ++p) { Symbol* sym = p->second; // Note that SYM may already have a dynamic symbol index, since // some symbols appear more than once in the symbol table, with // and without a version. if (!sym->should_add_dynsym_entry(this)) sym->set_dynsym_index(-1U); else if (!sym->has_dynsym_index()) { sym->set_dynsym_index(index); ++index; syms->push_back(sym); dynpool->add(sym->name(), false, NULL); // Record any version information. if (sym->version() != NULL) versions->record_version(this, dynpool, sym); // If the symbol is defined in a dynamic object and is // referenced in a regular object, then mark the dynamic // object as needed. This is used to implement --as-needed. if (sym->is_from_dynobj() && sym->in_reg()) sym->object()->set_is_needed(); } } // Finish up the versions. In some cases this may add new dynamic // symbols. index = versions->finalize(this, index, syms); return index; } // Set the final values for all the symbols. The index of the first // global symbol in the output file is *PLOCAL_SYMCOUNT. Record the // file offset OFF. Add their names to POOL. Return the new file // offset. Update *PLOCAL_SYMCOUNT if necessary. off_t Symbol_table::finalize(off_t off, off_t dynoff, size_t dyn_global_index, size_t dyncount, Stringpool* pool, unsigned int* plocal_symcount) { off_t ret; gold_assert(*plocal_symcount != 0); this->first_global_index_ = *plocal_symcount; this->dynamic_offset_ = dynoff; this->first_dynamic_global_index_ = dyn_global_index; this->dynamic_count_ = dyncount; if (parameters->target().get_size() == 32) { #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_32_LITTLE) ret = this->sized_finalize<32>(off, pool, plocal_symcount); #else gold_unreachable(); #endif } else if (parameters->target().get_size() == 64) { #if defined(HAVE_TARGET_64_BIG) || defined(HAVE_TARGET_64_LITTLE) ret = this->sized_finalize<64>(off, pool, plocal_symcount); #else gold_unreachable(); #endif } else gold_unreachable(); // Now that we have the final symbol table, we can reliably note // which symbols should get warnings. this->warnings_.note_warnings(this); return ret; } // SYM is going into the symbol table at *PINDEX. Add the name to // POOL, update *PINDEX and *POFF. template<int size> void Symbol_table::add_to_final_symtab(Symbol* sym, Stringpool* pool, unsigned int* pindex, off_t* poff) { sym->set_symtab_index(*pindex); pool->add(sym->name(), false, NULL); ++*pindex; *poff += elfcpp::Elf_sizes<size>::sym_size; } // Set the final value for all the symbols. This is called after // Layout::finalize, so all the output sections have their final // address. template<int size> off_t Symbol_table::sized_finalize(off_t off, Stringpool* pool, unsigned int* plocal_symcount) { off = align_address(off, size >> 3); this->offset_ = off; unsigned int index = *plocal_symcount; const unsigned int orig_index = index; // First do all the symbols which have been forced to be local, as // they must appear before all global symbols. for (Forced_locals::iterator p = this->forced_locals_.begin(); p != this->forced_locals_.end(); ++p) { Symbol* sym = *p; gold_assert(sym->is_forced_local()); if (this->sized_finalize_symbol<size>(sym)) { this->add_to_final_symtab<size>(sym, pool, &index, &off); ++*plocal_symcount; } } // Now do all the remaining symbols. for (Symbol_table_type::iterator p = this->table_.begin(); p != this->table_.end(); ++p) { Symbol* sym = p->second; if (this->sized_finalize_symbol<size>(sym)) this->add_to_final_symtab<size>(sym, pool, &index, &off); } this->output_count_ = index - orig_index; return off; } // Compute the final value of SYM and store status in location PSTATUS. // During relaxation, this may be called multiple times for a symbol to // compute its would-be final value in each relaxation pass. template<int size> typename Sized_symbol<size>::Value_type Symbol_table::compute_final_value( const Sized_symbol<size>* sym, Compute_final_value_status* pstatus) const { typedef typename Sized_symbol<size>::Value_type Value_type; Value_type value; switch (sym->source()) { case Symbol::FROM_OBJECT: { bool is_ordinary; unsigned int shndx = sym->shndx(&is_ordinary); if (!is_ordinary && shndx != elfcpp::SHN_ABS && !Symbol::is_common_shndx(shndx)) { *pstatus = CFVS_UNSUPPORTED_SYMBOL_SECTION; return 0; } Object* symobj = sym->object(); if (symobj->is_dynamic()) { value = 0; shndx = elfcpp::SHN_UNDEF; } else if (symobj->pluginobj() != NULL) { value = 0; shndx = elfcpp::SHN_UNDEF; } else if (shndx == elfcpp::SHN_UNDEF) value = 0; else if (!is_ordinary && (shndx == elfcpp::SHN_ABS || Symbol::is_common_shndx(shndx))) value = sym->value(); else { Relobj* relobj = static_cast<Relobj*>(symobj); Output_section* os = relobj->output_section(shndx); if (this->is_section_folded(relobj, shndx)) { gold_assert(os == NULL); // Get the os of the section it is folded onto. Section_id folded = this->icf_->get_folded_section(relobj, shndx); gold_assert(folded.first != NULL); Relobj* folded_obj = reinterpret_cast<Relobj*>(folded.first); unsigned folded_shndx = folded.second; os = folded_obj->output_section(folded_shndx); gold_assert(os != NULL); // Replace (relobj, shndx) with canonical ICF input section. shndx = folded_shndx; relobj = folded_obj; } uint64_t secoff64 = relobj->output_section_offset(shndx); if (os == NULL) { bool static_or_reloc = (parameters->doing_static_link() || parameters->options().relocatable()); gold_assert(static_or_reloc || sym->dynsym_index() == -1U); *pstatus = CFVS_NO_OUTPUT_SECTION; return 0; } if (secoff64 == -1ULL) { // The section needs special handling (e.g., a merge section). value = os->output_address(relobj, shndx, sym->value()); } else { Value_type secoff = convert_types<Value_type, uint64_t>(secoff64); if (sym->type() == elfcpp::STT_TLS) value = sym->value() + os->tls_offset() + secoff; else value = sym->value() + os->address() + secoff; } } } break; case Symbol::IN_OUTPUT_DATA: { Output_data* od = sym->output_data(); value = sym->value(); if (sym->type() != elfcpp::STT_TLS) value += od->address(); else { Output_section* os = od->output_section(); gold_assert(os != NULL); value += os->tls_offset() + (od->address() - os->address()); } if (sym->offset_is_from_end()) value += od->data_size(); } break; case Symbol::IN_OUTPUT_SEGMENT: { Output_segment* os = sym->output_segment(); value = sym->value(); if (sym->type() != elfcpp::STT_TLS) value += os->vaddr(); switch (sym->offset_base()) { case Symbol::SEGMENT_START: break; case Symbol::SEGMENT_END: value += os->memsz(); break; case Symbol::SEGMENT_BSS: value += os->filesz(); break; default: gold_unreachable(); } } break; case Symbol::IS_CONSTANT: value = sym->value(); break; case Symbol::IS_UNDEFINED: value = 0; break; default: gold_unreachable(); } *pstatus = CFVS_OK; return value; } // Finalize the symbol SYM. This returns true if the symbol should be // added to the symbol table, false otherwise. template<int size> bool Symbol_table::sized_finalize_symbol(Symbol* unsized_sym) { typedef typename Sized_symbol<size>::Value_type Value_type; Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(unsized_sym); // The default version of a symbol may appear twice in the symbol // table. We only need to finalize it once. if (sym->has_symtab_index()) return false; if (!sym->in_reg()) { gold_assert(!sym->has_symtab_index()); sym->set_symtab_index(-1U); gold_assert(sym->dynsym_index() == -1U); return false; } // If the symbol is only present on plugin files, the plugin decided we // don't need it. if (!sym->in_real_elf()) { gold_assert(!sym->has_symtab_index()); sym->set_symtab_index(-1U); return false; } // Compute final symbol value. Compute_final_value_status status; Value_type value = this->compute_final_value(sym, &status); switch (status) { case CFVS_OK: break; case CFVS_UNSUPPORTED_SYMBOL_SECTION: { bool is_ordinary; unsigned int shndx = sym->shndx(&is_ordinary); gold_error(_("%s: unsupported symbol section 0x%x"), sym->demangled_name().c_str(), shndx); } break; case CFVS_NO_OUTPUT_SECTION: sym->set_symtab_index(-1U); return false; default: gold_unreachable(); } sym->set_value(value); if (parameters->options().strip_all() || !parameters->options().should_retain_symbol(sym->name())) { sym->set_symtab_index(-1U); return false; } return true; } // Write out the global symbols. void Symbol_table::write_globals(const Stringpool* sympool, const Stringpool* dynpool, Output_symtab_xindex* symtab_xindex, Output_symtab_xindex* dynsym_xindex, Output_file* of) const { switch (parameters->size_and_endianness()) { #ifdef HAVE_TARGET_32_LITTLE case Parameters::TARGET_32_LITTLE: this->sized_write_globals<32, false>(sympool, dynpool, symtab_xindex, dynsym_xindex, of); break; #endif #ifdef HAVE_TARGET_32_BIG case Parameters::TARGET_32_BIG: this->sized_write_globals<32, true>(sympool, dynpool, symtab_xindex, dynsym_xindex, of); break; #endif #ifdef HAVE_TARGET_64_LITTLE case Parameters::TARGET_64_LITTLE: this->sized_write_globals<64, false>(sympool, dynpool, symtab_xindex, dynsym_xindex, of); break; #endif #ifdef HAVE_TARGET_64_BIG case Parameters::TARGET_64_BIG: this->sized_write_globals<64, true>(sympool, dynpool, symtab_xindex, dynsym_xindex, of); break; #endif default: gold_unreachable(); } } // Write out the global symbols. template<int size, bool big_endian> void Symbol_table::sized_write_globals(const Stringpool* sympool, const Stringpool* dynpool, Output_symtab_xindex* symtab_xindex, Output_symtab_xindex* dynsym_xindex, Output_file* of) const { const Target& target = parameters->target(); const int sym_size = elfcpp::Elf_sizes<size>::sym_size; const unsigned int output_count = this->output_count_; const section_size_type oview_size = output_count * sym_size; const unsigned int first_global_index = this->first_global_index_; unsigned char* psyms; if (this->offset_ == 0 || output_count == 0) psyms = NULL; else psyms = of->get_output_view(this->offset_, oview_size); const unsigned int dynamic_count = this->dynamic_count_; const section_size_type dynamic_size = dynamic_count * sym_size; const unsigned int first_dynamic_global_index = this->first_dynamic_global_index_; unsigned char* dynamic_view; if (this->dynamic_offset_ == 0 || dynamic_count == 0) dynamic_view = NULL; else dynamic_view = of->get_output_view(this->dynamic_offset_, dynamic_size); for (Symbol_table_type::const_iterator p = this->table_.begin(); p != this->table_.end(); ++p) { Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second); // Possibly warn about unresolved symbols in shared libraries. this->warn_about_undefined_dynobj_symbol(sym); unsigned int sym_index = sym->symtab_index(); unsigned int dynsym_index; if (dynamic_view == NULL) dynsym_index = -1U; else dynsym_index = sym->dynsym_index(); if (sym_index == -1U && dynsym_index == -1U) { // This symbol is not included in the output file. continue; } unsigned int shndx; typename elfcpp::Elf_types<size>::Elf_Addr sym_value = sym->value(); typename elfcpp::Elf_types<size>::Elf_Addr dynsym_value = sym_value; elfcpp::STB binding = sym->binding(); switch (sym->source()) { case Symbol::FROM_OBJECT: { bool is_ordinary; unsigned int in_shndx = sym->shndx(&is_ordinary); if (!is_ordinary && in_shndx != elfcpp::SHN_ABS && !Symbol::is_common_shndx(in_shndx)) { gold_error(_("%s: unsupported symbol section 0x%x"), sym->demangled_name().c_str(), in_shndx); shndx = in_shndx; } else { Object* symobj = sym->object(); if (symobj->is_dynamic()) { if (sym->needs_dynsym_value()) dynsym_value = target.dynsym_value(sym); shndx = elfcpp::SHN_UNDEF; if (sym->is_undef_binding_weak()) binding = elfcpp::STB_WEAK; else binding = elfcpp::STB_GLOBAL; } else if (symobj->pluginobj() != NULL) shndx = elfcpp::SHN_UNDEF; else if (in_shndx == elfcpp::SHN_UNDEF || (!is_ordinary && (in_shndx == elfcpp::SHN_ABS || Symbol::is_common_shndx(in_shndx)))) shndx = in_shndx; else { Relobj* relobj = static_cast<Relobj*>(symobj); Output_section* os = relobj->output_section(in_shndx); if (this->is_section_folded(relobj, in_shndx)) { // This global symbol must be written out even though // it is folded. // Get the os of the section it is folded onto. Section_id folded = this->icf_->get_folded_section(relobj, in_shndx); gold_assert(folded.first !=NULL); Relobj* folded_obj = reinterpret_cast<Relobj*>(folded.first); os = folded_obj->output_section(folded.second); gold_assert(os != NULL); } gold_assert(os != NULL); shndx = os->out_shndx(); if (shndx >= elfcpp::SHN_LORESERVE) { if (sym_index != -1U) symtab_xindex->add(sym_index, shndx); if (dynsym_index != -1U) dynsym_xindex->add(dynsym_index, shndx); shndx = elfcpp::SHN_XINDEX; } // In object files symbol values are section // relative. if (parameters->options().relocatable()) sym_value -= os->address(); } } } break; case Symbol::IN_OUTPUT_DATA: shndx = sym->output_data()->out_shndx(); if (shndx >= elfcpp::SHN_LORESERVE) { if (sym_index != -1U) symtab_xindex->add(sym_index, shndx); if (dynsym_index != -1U) dynsym_xindex->add(dynsym_index, shndx); shndx = elfcpp::SHN_XINDEX; } break; case Symbol::IN_OUTPUT_SEGMENT: shndx = elfcpp::SHN_ABS; break; case Symbol::IS_CONSTANT: shndx = elfcpp::SHN_ABS; break; case Symbol::IS_UNDEFINED: shndx = elfcpp::SHN_UNDEF; break; default: gold_unreachable(); } if (sym_index != -1U) { sym_index -= first_global_index; gold_assert(sym_index < output_count); unsigned char* ps = psyms + (sym_index * sym_size); this->sized_write_symbol<size, big_endian>(sym, sym_value, shndx, binding, sympool, ps); } if (dynsym_index != -1U) { dynsym_index -= first_dynamic_global_index; gold_assert(dynsym_index < dynamic_count); unsigned char* pd = dynamic_view + (dynsym_index * sym_size); this->sized_write_symbol<size, big_endian>(sym, dynsym_value, shndx, binding, dynpool, pd); } } of->write_output_view(this->offset_, oview_size, psyms); if (dynamic_view != NULL) of->write_output_view(this->dynamic_offset_, dynamic_size, dynamic_view); } // Write out the symbol SYM, in section SHNDX, to P. POOL is the // strtab holding the name. template<int size, bool big_endian> void Symbol_table::sized_write_symbol( Sized_symbol<size>* sym, typename elfcpp::Elf_types<size>::Elf_Addr value, unsigned int shndx, elfcpp::STB binding, const Stringpool* pool, unsigned char* p) const { elfcpp::Sym_write<size, big_endian> osym(p); osym.put_st_name(pool->get_offset(sym->name())); osym.put_st_value(value); // Use a symbol size of zero for undefined symbols from shared libraries. if (shndx == elfcpp::SHN_UNDEF && sym->is_from_dynobj()) osym.put_st_size(0); else osym.put_st_size(sym->symsize()); elfcpp::STT type = sym->type(); // Turn IFUNC symbols from shared libraries into normal FUNC symbols. if (type == elfcpp::STT_GNU_IFUNC && sym->is_from_dynobj()) type = elfcpp::STT_FUNC; // A version script may have overridden the default binding. if (sym->is_forced_local()) osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL, type)); else osym.put_st_info(elfcpp::elf_st_info(binding, type)); osym.put_st_other(elfcpp::elf_st_other(sym->visibility(), sym->nonvis())); osym.put_st_shndx(shndx); } // Check for unresolved symbols in shared libraries. This is // controlled by the --allow-shlib-undefined option. // We only warn about libraries for which we have seen all the // DT_NEEDED entries. We don't try to track down DT_NEEDED entries // which were not seen in this link. If we didn't see a DT_NEEDED // entry, we aren't going to be able to reliably report whether the // symbol is undefined. // We also don't warn about libraries found in a system library // directory (e.g., /lib or /usr/lib); we assume that those libraries // are OK. This heuristic avoids problems on GNU/Linux, in which -ldl // can have undefined references satisfied by ld-linux.so. inline void Symbol_table::warn_about_undefined_dynobj_symbol(Symbol* sym) const { bool dummy; if (sym->source() == Symbol::FROM_OBJECT && sym->object()->is_dynamic() && sym->shndx(&dummy) == elfcpp::SHN_UNDEF && sym->binding() != elfcpp::STB_WEAK && !parameters->options().allow_shlib_undefined() && !parameters->target().is_defined_by_abi(sym) && !sym->object()->is_in_system_directory()) { // A very ugly cast. Dynobj* dynobj = static_cast<Dynobj*>(sym->object()); if (!dynobj->has_unknown_needed_entries()) gold_undefined_symbol(sym); } } // Write out a section symbol. Return the update offset. void Symbol_table::write_section_symbol(const Output_section* os, Output_symtab_xindex* symtab_xindex, Output_file* of, off_t offset) const { switch (parameters->size_and_endianness()) { #ifdef HAVE_TARGET_32_LITTLE case Parameters::TARGET_32_LITTLE: this->sized_write_section_symbol<32, false>(os, symtab_xindex, of, offset); break; #endif #ifdef HAVE_TARGET_32_BIG case Parameters::TARGET_32_BIG: this->sized_write_section_symbol<32, true>(os, symtab_xindex, of, offset); break; #endif #ifdef HAVE_TARGET_64_LITTLE case Parameters::TARGET_64_LITTLE: this->sized_write_section_symbol<64, false>(os, symtab_xindex, of, offset); break; #endif #ifdef HAVE_TARGET_64_BIG case Parameters::TARGET_64_BIG: this->sized_write_section_symbol<64, true>(os, symtab_xindex, of, offset); break; #endif default: gold_unreachable(); } } // Write out a section symbol, specialized for size and endianness. template<int size, bool big_endian> void Symbol_table::sized_write_section_symbol(const Output_section* os, Output_symtab_xindex* symtab_xindex, Output_file* of, off_t offset) const { const int sym_size = elfcpp::Elf_sizes<size>::sym_size; unsigned char* pov = of->get_output_view(offset, sym_size); elfcpp::Sym_write<size, big_endian> osym(pov); osym.put_st_name(0); if (parameters->options().relocatable()) osym.put_st_value(0); else osym.put_st_value(os->address()); osym.put_st_size(0); osym.put_st_info(elfcpp::elf_st_info(elfcpp::STB_LOCAL, elfcpp::STT_SECTION)); osym.put_st_other(elfcpp::elf_st_other(elfcpp::STV_DEFAULT, 0)); unsigned int shndx = os->out_shndx(); if (shndx >= elfcpp::SHN_LORESERVE) { symtab_xindex->add(os->symtab_index(), shndx); shndx = elfcpp::SHN_XINDEX; } osym.put_st_shndx(shndx); of->write_output_view(offset, sym_size, pov); } // Print statistical information to stderr. This is used for --stats. void Symbol_table::print_stats() const { #if defined(HAVE_TR1_UNORDERED_MAP) || defined(HAVE_EXT_HASH_MAP) fprintf(stderr, _("%s: symbol table entries: %zu; buckets: %zu\n"), program_name, this->table_.size(), this->table_.bucket_count()); #else fprintf(stderr, _("%s: symbol table entries: %zu\n"), program_name, this->table_.size()); #endif this->namepool_.print_stats("symbol table stringpool"); } // We check for ODR violations by looking for symbols with the same // name for which the debugging information reports that they were // defined in disjoint source locations. When comparing the source // location, we consider instances with the same base filename to be // the same. This is because different object files/shared libraries // can include the same header file using different paths, and // different optimization settings can make the line number appear to // be a couple lines off, and we don't want to report an ODR violation // in those cases. // This struct is used to compare line information, as returned by // Dwarf_line_info::one_addr2line. It implements a < comparison // operator used with std::sort. struct Odr_violation_compare { bool operator()(const std::string& s1, const std::string& s2) const { // Inputs should be of the form "dirname/filename:linenum" where // "dirname/" is optional. We want to compare just the filename:linenum. // Find the last '/' in each string. std::string::size_type s1begin = s1.rfind('/'); std::string::size_type s2begin = s2.rfind('/'); // If there was no '/' in a string, start at the beginning. if (s1begin == std::string::npos) s1begin = 0; if (s2begin == std::string::npos) s2begin = 0; return s1.compare(s1begin, std::string::npos, s2, s2begin, std::string::npos) < 0; } }; // Returns all of the lines attached to LOC, not just the one the // instruction actually came from. std::vector<std::string> Symbol_table::linenos_from_loc(const Task* task, const Symbol_location& loc) { // We need to lock the object in order to read it. This // means that we have to run in a singleton Task. If we // want to run this in a general Task for better // performance, we will need one Task for object, plus // appropriate locking to ensure that we don't conflict with // other uses of the object. Also note, one_addr2line is not // currently thread-safe. Task_lock_obj<Object> tl(task, loc.object); std::vector<std::string> result; // 16 is the size of the object-cache that one_addr2line should use. std::string canonical_result = Dwarf_line_info::one_addr2line( loc.object, loc.shndx, loc.offset, 16, &result); if (!canonical_result.empty()) result.push_back(canonical_result); return result; } // OutputIterator that records if it was ever assigned to. This // allows it to be used with std::set_intersection() to check for // intersection rather than computing the intersection. struct Check_intersection { Check_intersection() : value_(false) {} bool had_intersection() const { return this->value_; } Check_intersection& operator++() { return *this; } Check_intersection& operator*() { return *this; } template<typename T> Check_intersection& operator=(const T&) { this->value_ = true; return *this; } private: bool value_; }; // Check candidate_odr_violations_ to find symbols with the same name // but apparently different definitions (different source-file/line-no // for each line assigned to the first instruction). void Symbol_table::detect_odr_violations(const Task* task, const char* output_file_name) const { for (Odr_map::const_iterator it = candidate_odr_violations_.begin(); it != candidate_odr_violations_.end(); ++it) { const char* const symbol_name = it->first; std::string first_object_name; std::vector<std::string> first_object_linenos; Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator locs = it->second.begin(); const Unordered_set<Symbol_location, Symbol_location_hash>::const_iterator locs_end = it->second.end(); for (; locs != locs_end && first_object_linenos.empty(); ++locs) { // Save the line numbers from the first definition to // compare to the other definitions. Ideally, we'd compare // every definition to every other, but we don't want to // take O(N^2) time to do this. This shortcut may cause // false negatives that appear or disappear depending on the // link order, but it won't cause false positives. first_object_name = locs->object->name(); first_object_linenos = this->linenos_from_loc(task, *locs); } // Sort by Odr_violation_compare to make std::set_intersection work. std::sort(first_object_linenos.begin(), first_object_linenos.end(), Odr_violation_compare()); for (; locs != locs_end; ++locs) { std::vector<std::string> linenos = this->linenos_from_loc(task, *locs); // linenos will be empty if we couldn't parse the debug info. if (linenos.empty()) continue; // Sort by Odr_violation_compare to make std::set_intersection work. std::sort(linenos.begin(), linenos.end(), Odr_violation_compare()); Check_intersection intersection_result = std::set_intersection(first_object_linenos.begin(), first_object_linenos.end(), linenos.begin(), linenos.end(), Check_intersection(), Odr_violation_compare()); if (!intersection_result.had_intersection()) { gold_warning(_("while linking %s: symbol '%s' defined in " "multiple places (possible ODR violation):"), output_file_name, demangle(symbol_name).c_str()); // This only prints one location from each definition, // which may not be the location we expect to intersect // with another definition. We could print the whole // set of locations, but that seems too verbose. gold_assert(!first_object_linenos.empty()); gold_assert(!linenos.empty()); fprintf(stderr, _(" %s from %s\n"), first_object_linenos[0].c_str(), first_object_name.c_str()); fprintf(stderr, _(" %s from %s\n"), linenos[0].c_str(), locs->object->name().c_str()); // Only print one broken pair, to avoid needing to // compare against a list of the disjoint definition // locations we've found so far. (If we kept comparing // against just the first one, we'd get a lot of // redundant complaints about the second definition // location.) break; } } } // We only call one_addr2line() in this function, so we can clear its cache. Dwarf_line_info::clear_addr2line_cache(); } // Warnings functions. // Add a new warning. void Warnings::add_warning(Symbol_table* symtab, const char* name, Object* obj, const std::string& warning) { name = symtab->canonicalize_name(name); this->warnings_[name].set(obj, warning); } // Look through the warnings and mark the symbols for which we should // warn. This is called during Layout::finalize when we know the // sources for all the symbols. void Warnings::note_warnings(Symbol_table* symtab) { for (Warning_table::iterator p = this->warnings_.begin(); p != this->warnings_.end(); ++p) { Symbol* sym = symtab->lookup(p->first, NULL); if (sym != NULL && sym->source() == Symbol::FROM_OBJECT && sym->object() == p->second.object) sym->set_has_warning(); } } // Issue a warning. This is called when we see a relocation against a // symbol for which has a warning. template<int size, bool big_endian> void Warnings::issue_warning(const Symbol* sym, const Relocate_info<size, big_endian>* relinfo, size_t relnum, off_t reloffset) const { gold_assert(sym->has_warning()); Warning_table::const_iterator p = this->warnings_.find(sym->name()); gold_assert(p != this->warnings_.end()); gold_warning_at_location(relinfo, relnum, reloffset, "%s", p->second.text.c_str()); } // Instantiate the templates we need. We could use the configure // script to restrict this to only the ones needed for implemented // targets. #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) template void Sized_symbol<32>::allocate_common(Output_data*, Value_type); #endif #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) template void Sized_symbol<64>::allocate_common(Output_data*, Value_type); #endif #ifdef HAVE_TARGET_32_LITTLE template void Symbol_table::add_from_relobj<32, false>( Sized_relobj_file<32, false>* relobj, const unsigned char* syms, size_t count, size_t symndx_offset, const char* sym_names, size_t sym_name_size, Sized_relobj_file<32, false>::Symbols* sympointers, size_t* defined); #endif #ifdef HAVE_TARGET_32_BIG template void Symbol_table::add_from_relobj<32, true>( Sized_relobj_file<32, true>* relobj, const unsigned char* syms, size_t count, size_t symndx_offset, const char* sym_names, size_t sym_name_size, Sized_relobj_file<32, true>::Symbols* sympointers, size_t* defined); #endif #ifdef HAVE_TARGET_64_LITTLE template void Symbol_table::add_from_relobj<64, false>( Sized_relobj_file<64, false>* relobj, const unsigned char* syms, size_t count, size_t symndx_offset, const char* sym_names, size_t sym_name_size, Sized_relobj_file<64, false>::Symbols* sympointers, size_t* defined); #endif #ifdef HAVE_TARGET_64_BIG template void Symbol_table::add_from_relobj<64, true>( Sized_relobj_file<64, true>* relobj, const unsigned char* syms, size_t count, size_t symndx_offset, const char* sym_names, size_t sym_name_size, Sized_relobj_file<64, true>::Symbols* sympointers, size_t* defined); #endif #ifdef HAVE_TARGET_32_LITTLE template Symbol* Symbol_table::add_from_pluginobj<32, false>( Sized_pluginobj<32, false>* obj, const char* name, const char* ver, elfcpp::Sym<32, false>* sym); #endif #ifdef HAVE_TARGET_32_BIG template Symbol* Symbol_table::add_from_pluginobj<32, true>( Sized_pluginobj<32, true>* obj, const char* name, const char* ver, elfcpp::Sym<32, true>* sym); #endif #ifdef HAVE_TARGET_64_LITTLE template Symbol* Symbol_table::add_from_pluginobj<64, false>( Sized_pluginobj<64, false>* obj, const char* name, const char* ver, elfcpp::Sym<64, false>* sym); #endif #ifdef HAVE_TARGET_64_BIG template Symbol* Symbol_table::add_from_pluginobj<64, true>( Sized_pluginobj<64, true>* obj, const char* name, const char* ver, elfcpp::Sym<64, true>* sym); #endif #ifdef HAVE_TARGET_32_LITTLE template void Symbol_table::add_from_dynobj<32, false>( Sized_dynobj<32, false>* dynobj, const unsigned char* syms, size_t count, const char* sym_names, size_t sym_name_size, const unsigned char* versym, size_t versym_size, const std::vector<const char*>* version_map, Sized_relobj_file<32, false>::Symbols* sympointers, size_t* defined); #endif #ifdef HAVE_TARGET_32_BIG template void Symbol_table::add_from_dynobj<32, true>( Sized_dynobj<32, true>* dynobj, const unsigned char* syms, size_t count, const char* sym_names, size_t sym_name_size, const unsigned char* versym, size_t versym_size, const std::vector<const char*>* version_map, Sized_relobj_file<32, true>::Symbols* sympointers, size_t* defined); #endif #ifdef HAVE_TARGET_64_LITTLE template void Symbol_table::add_from_dynobj<64, false>( Sized_dynobj<64, false>* dynobj, const unsigned char* syms, size_t count, const char* sym_names, size_t sym_name_size, const unsigned char* versym, size_t versym_size, const std::vector<const char*>* version_map, Sized_relobj_file<64, false>::Symbols* sympointers, size_t* defined); #endif #ifdef HAVE_TARGET_64_BIG template void Symbol_table::add_from_dynobj<64, true>( Sized_dynobj<64, true>* dynobj, const unsigned char* syms, size_t count, const char* sym_names, size_t sym_name_size, const unsigned char* versym, size_t versym_size, const std::vector<const char*>* version_map, Sized_relobj_file<64, true>::Symbols* sympointers, size_t* defined); #endif #ifdef HAVE_TARGET_32_LITTLE template Symbol* Symbol_table::add_from_incrobj( Object* obj, const char* name, const char* ver, elfcpp::Sym<32, false>* sym); #endif #ifdef HAVE_TARGET_32_BIG template Symbol* Symbol_table::add_from_incrobj( Object* obj, const char* name, const char* ver, elfcpp::Sym<32, true>* sym); #endif #ifdef HAVE_TARGET_64_LITTLE template Symbol* Symbol_table::add_from_incrobj( Object* obj, const char* name, const char* ver, elfcpp::Sym<64, false>* sym); #endif #ifdef HAVE_TARGET_64_BIG template Symbol* Symbol_table::add_from_incrobj( Object* obj, const char* name, const char* ver, elfcpp::Sym<64, true>* sym); #endif #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) template void Symbol_table::define_with_copy_reloc<32>( Sized_symbol<32>* sym, Output_data* posd, elfcpp::Elf_types<32>::Elf_Addr value); #endif #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) template void Symbol_table::define_with_copy_reloc<64>( Sized_symbol<64>* sym, Output_data* posd, elfcpp::Elf_types<64>::Elf_Addr value); #endif #ifdef HAVE_TARGET_32_LITTLE template void Warnings::issue_warning<32, false>(const Symbol* sym, const Relocate_info<32, false>* relinfo, size_t relnum, off_t reloffset) const; #endif #ifdef HAVE_TARGET_32_BIG template void Warnings::issue_warning<32, true>(const Symbol* sym, const Relocate_info<32, true>* relinfo, size_t relnum, off_t reloffset) const; #endif #ifdef HAVE_TARGET_64_LITTLE template void Warnings::issue_warning<64, false>(const Symbol* sym, const Relocate_info<64, false>* relinfo, size_t relnum, off_t reloffset) const; #endif #ifdef HAVE_TARGET_64_BIG template void Warnings::issue_warning<64, true>(const Symbol* sym, const Relocate_info<64, true>* relinfo, size_t relnum, off_t reloffset) const; #endif } // End namespace gold.
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