// symtab.cc -- the gold symbol table // Copyright 2006, 2007 Free Software Foundation, Inc. // Written by Ian Lance Taylor . // 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 #include #include #include "object.h" #include "dynobj.h" #include "output.h" #include "target.h" #include "workqueue.h" #include "symtab.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_offset_ = 0; this->plt_offset_ = 0; this->type_ = type; this->binding_ = binding; this->visibility_ = visibility; this->nonvis_ = nonvis; this->is_target_special_ = false; this->is_def_ = false; this->is_forwarder_ = false; this->needs_dynsym_entry_ = false; this->in_reg_ = false; this->in_dyn_ = false; this->has_got_offset_ = false; this->has_plt_offset_ = false; this->has_warning_ = false; } // Initialize the fields in the base class Symbol for SYM in OBJECT. template void Symbol::init_base(const char* name, const char* version, Object* object, const elfcpp::Sym& sym) { 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; // FIXME: Handle SHN_XINDEX. this->u_.from_object.shndx = sym.get_st_shndx(); this->source_ = FROM_OBJECT; this->in_reg_ = !object->is_dynamic(); this->in_dyn_ = object->is_dynamic(); } // Initialize the fields in the base class Symbol for a symbol defined // in an Output_data. void Symbol::init_base(const char* name, Output_data* od, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis, bool offset_is_from_end) { this->init_fields(name, NULL, 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; } // Initialize the fields in the base class Symbol for a symbol defined // in an Output_segment. void Symbol::init_base(const char* name, Output_segment* os, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis, Segment_offset_base offset_base) { this->init_fields(name, NULL, 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; } // Initialize the fields in the base class Symbol for a symbol defined // as a constant. void Symbol::init_base(const char* name, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis) { this->init_fields(name, NULL, type, binding, visibility, nonvis); this->source_ = CONSTANT; this->in_reg_ = true; } // Initialize the fields in Sized_symbol for SYM in OBJECT. template template void Sized_symbol::init(const char* name, const char* version, Object* object, const elfcpp::Sym& sym) { this->init_base(name, version, object, sym); 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 void Sized_symbol::init(const char* name, 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(name, 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 void Sized_symbol::init(const char* name, 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(name, 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 void Sized_symbol::init(const char* name, Value_type value, Size_type symsize, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis) { this->init_base(name, type, binding, visibility, nonvis); this->value_ = value; this->symsize_ = symsize; } // Class Symbol_table. Symbol_table::Symbol_table() : size_(0), saw_undefined_(0), offset_(0), table_(), namepool_(), forwarders_(), commons_(), warnings_() { } Symbol_table::~Symbol_table() { } // The hash function. The key is always canonicalized, so we use a // simple combination of the pointers. size_t Symbol_table::Symbol_table_hash::operator()(const Symbol_table_key& key) const { return key.first ^ key.second; } // The symbol table key equality function. This is only called with // canonicalized name and version strings, so we can use pointer // comparison. 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; } // 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_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 void Symbol_table::resolve(Sized_symbol* to, const Sized_symbol* from, const char* version ACCEPT_SIZE_ENDIAN) { unsigned char buf[elfcpp::Elf_sizes::sym_size]; elfcpp::Sym_write esym(buf); // We don't bother to set the st_name 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()); esym.put_st_shndx(from->shndx()); Symbol_table::resolve(to, esym.sym(), from->object(), version); if (from->in_reg()) to->set_in_reg(); if (from->in_dyn()) to->set_in_dyn(); } // 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. // If DEF 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. template Symbol* Symbol_table::add_from_object(Object* object, const char *name, Stringpool::Key name_key, const char *version, Stringpool::Key version_key, bool def, const elfcpp::Sym& sym) { Symbol* const snull = NULL; std::pair ins = this->table_.insert(std::make_pair(std::make_pair(name_key, version_key), snull)); std::pair insdef = std::make_pair(this->table_.end(), false); if (def) { const Stringpool::Key vnull_key = 0; insdef = 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* ret; bool was_undefined; bool was_common; if (!ins.second) { // We already have an entry for NAME/VERSION. ret = this->get_sized_symbol SELECT_SIZE_NAME(size) (ins.first->second SELECT_SIZE(size)); gold_assert(ret != NULL); was_undefined = ret->is_undefined(); was_common = ret->is_common(); Symbol_table::resolve(ret, sym, object, version); if (def) { if (insdef.second) { // This is the first time we have seen NAME/NULL. Make // NAME/NULL point to NAME/VERSION. insdef.first->second = ret; } else if (insdef.first->second != ret) { // This is the unfortunate case where we already have // entries for both NAME/VERSION and NAME/NULL. const Sized_symbol* sym2; sym2 = this->get_sized_symbol SELECT_SIZE_NAME(size) ( insdef.first->second SELECT_SIZE(size)); Symbol_table::resolve SELECT_SIZE_ENDIAN_NAME(size, big_endian) ( ret, sym2, version SELECT_SIZE_ENDIAN(size, big_endian)); this->make_forwarder(insdef.first->second, ret); insdef.first->second = ret; } } } else { // This is the first time we have seen NAME/VERSION. gold_assert(ins.first->second == NULL); was_undefined = false; was_common = false; if (def && !insdef.second) { // We already have an entry for NAME/NULL. If we override // it, then change it to NAME/VERSION. ret = this->get_sized_symbol SELECT_SIZE_NAME(size) ( insdef.first->second SELECT_SIZE(size)); Symbol_table::resolve(ret, sym, object, version); ins.first->second = ret; } else { Sized_target* target = object->sized_target SELECT_SIZE_ENDIAN_NAME(size, big_endian) ( SELECT_SIZE_ENDIAN_ONLY(size, big_endian)); if (!target->has_make_symbol()) ret = new Sized_symbol(); else { ret = target->make_symbol(); if (ret == NULL) { // This means that we don't want a symbol table // entry after all. if (!def) this->table_.erase(ins.first); else { this->table_.erase(insdef.first); // Inserting insdef invalidated ins. this->table_.erase(std::make_pair(name_key, version_key)); } return NULL; } } ret->init(name, version, object, sym); ins.first->second = ret; if (def) { // This is the first time we have seen NAME/NULL. Point // it at the new entry for NAME/VERSION. gold_assert(insdef.second); insdef.first->second = ret; } } } // Record every time we see a new undefined symbol, to speed up // archive groups. if (!was_undefined && ret->is_undefined()) ++this->saw_undefined_; // Keep track of common symbols, to speed up common symbol // allocation. if (!was_common && ret->is_common()) this->commons_.push_back(ret); return ret; } // Add all the symbols in a relocatable object to the hash table. template void Symbol_table::add_from_relobj( Sized_relobj* relobj, const unsigned char* syms, size_t count, const char* sym_names, size_t sym_name_size, Symbol** sympointers) { // We take the size from the first object we see. if (this->get_size() == 0) this->set_size(size); if (size != this->get_size() || size != relobj->target()->get_size()) { fprintf(stderr, _("%s: %s: mixing 32-bit and 64-bit ELF objects\n"), program_name, relobj->name().c_str()); gold_exit(false); } const int sym_size = elfcpp::Elf_sizes::sym_size; const unsigned char* p = syms; for (size_t i = 0; i < count; ++i, p += sym_size) { elfcpp::Sym sym(p); elfcpp::Sym* psym = &sym; unsigned int st_name = psym->get_st_name(); if (st_name >= sym_name_size) { fprintf(stderr, _("%s: %s: bad global symbol name offset %u at %lu\n"), program_name, relobj->name().c_str(), st_name, static_cast(i)); gold_exit(false); } const char* name = sym_names + st_name; // A symbol defined in a section which we are not including must // be treated as an undefined symbol. unsigned char symbuf[sym_size]; elfcpp::Sym sym2(symbuf); unsigned int st_shndx = psym->get_st_shndx(); if (st_shndx != elfcpp::SHN_UNDEF && st_shndx < elfcpp::SHN_LORESERVE && !relobj->is_section_included(st_shndx)) { memcpy(symbuf, p, sym_size); elfcpp::Sym_write sw(symbuf); sw.put_st_shndx(elfcpp::SHN_UNDEF); psym = &sym2; } // 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, '@'); Symbol* res; if (ver == NULL) { Stringpool::Key name_key; name = this->namepool_.add(name, &name_key); res = this->add_from_object(relobj, name, name_key, NULL, 0, false, *psym); } else { Stringpool::Key name_key; name = this->namepool_.add(name, ver - name, &name_key); bool def = false; ++ver; if (*ver == '@') { def = true; ++ver; } Stringpool::Key ver_key; ver = this->namepool_.add(ver, &ver_key); res = this->add_from_object(relobj, name, name_key, ver, ver_key, def, *psym); } *sympointers++ = res; } } // Add all the symbols in a dynamic object to the hash table. template void Symbol_table::add_from_dynobj( Sized_dynobj* 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* version_map) { // We take the size from the first object we see. if (this->get_size() == 0) this->set_size(size); if (size != this->get_size() || size != dynobj->target()->get_size()) { fprintf(stderr, _("%s: %s: mixing 32-bit and 64-bit ELF objects\n"), program_name, dynobj->name().c_str()); gold_exit(false); } if (versym != NULL && versym_size / 2 < count) { fprintf(stderr, _("%s: %s: too few symbol versions\n"), program_name, dynobj->name().c_str()); gold_exit(false); } const int sym_size = elfcpp::Elf_sizes::sym_size; 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 sym(p); // Ignore symbols with local binding. if (sym.get_st_bind() == elfcpp::STB_LOCAL) continue; unsigned int st_name = sym.get_st_name(); if (st_name >= sym_name_size) { fprintf(stderr, _("%s: %s: bad symbol name offset %u at %lu\n"), program_name, dynobj->name().c_str(), st_name, static_cast(i)); gold_exit(false); } const char* name = sym_names + st_name; if (versym == NULL) { Stringpool::Key name_key; name = this->namepool_.add(name, &name_key); this->add_from_object(dynobj, name, name_key, NULL, 0, false, sym); continue; } // 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(elfcpp::VER_NDX_LOCAL) && sym.get_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, &name_key); if (v == static_cast(elfcpp::VER_NDX_LOCAL) || v == static_cast(elfcpp::VER_NDX_GLOBAL)) { // This symbol does not have a version. this->add_from_object(dynobj, name, name_key, NULL, 0, false, sym); continue; } if (v >= version_map->size()) { fprintf(stderr, _("%s: %s: versym for symbol %zu out of range: %u\n"), program_name, dynobj->name().c_str(), i, v); gold_exit(false); } const char* version = (*version_map)[v]; if (version == NULL) { fprintf(stderr, _("%s: %s: versym for symbol %zu has no name: %u\n"), program_name, dynobj->name().c_str(), i, v); gold_exit(false); } Stringpool::Key version_key; version = this->namepool_.add(version, &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 (sym.get_st_shndx() == elfcpp::SHN_ABS && name_key == version_key) { this->add_from_object(dynobj, name, name_key, NULL, 0, false, sym); continue; } const bool def = !hidden && sym.get_st_shndx() != elfcpp::SHN_UNDEF; this->add_from_object(dynobj, name, name_key, version, version_key, def, sym); } } // 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 canonicalizes *PNAME and *PVERSION. template Sized_symbol* Symbol_table::define_special_symbol(const Target* target, const char** pname, const char** pversion, bool only_if_ref, Sized_symbol** poldsym ACCEPT_SIZE_ENDIAN) { gold_assert(this->size_ == size); Symbol* oldsym; Sized_symbol* sym; bool add_to_table = false; typename Symbol_table_type::iterator add_loc = this->table_.end(); if (only_if_ref) { oldsym = this->lookup(*pname, *pversion); if (oldsym == NULL || !oldsym->is_undefined()) return NULL; *pname = oldsym->name(); *pversion = oldsym->version(); } else { // Canonicalize NAME and VERSION. Stringpool::Key name_key; *pname = this->namepool_.add(*pname, &name_key); Stringpool::Key version_key = 0; if (*pversion != NULL) *pversion = this->namepool_.add(*pversion, &version_key); Symbol* const snull = NULL; std::pair ins = this->table_.insert(std::make_pair(std::make_pair(name_key, version_key), snull)); if (!ins.second) { // We already have a symbol table entry for NAME/VERSION. oldsym = ins.first->second; gold_assert(oldsym != NULL); } else { // We haven't seen this symbol before. gold_assert(ins.first->second == NULL); add_to_table = true; add_loc = ins.first; oldsym = NULL; } } if (!target->has_make_symbol()) sym = new Sized_symbol(); else { gold_assert(target->get_size() == size); gold_assert(target->is_big_endian() ? big_endian : !big_endian); typedef Sized_target My_target; const My_target* sized_target = static_cast(target); sym = sized_target->make_symbol(); if (sym == NULL) return NULL; } if (add_to_table) add_loc->second = sym; else gold_assert(oldsym != NULL); *poldsym = this->get_sized_symbol SELECT_SIZE_NAME(size) (oldsym SELECT_SIZE(size)); return sym; } // Define a symbol based on an Output_data. Symbol* Symbol_table::define_in_output_data(const Target* target, const char* name, const char* version, 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) { gold_assert(target->get_size() == this->size_); if (this->size_ == 32) { #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) return this->do_define_in_output_data<32>(target, name, version, od, value, symsize, type, binding, visibility, nonvis, offset_is_from_end, only_if_ref); #else gold_unreachable(); #endif } else if (this->size_ == 64) { #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) return this->do_define_in_output_data<64>(target, name, version, 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 Sized_symbol* Symbol_table::do_define_in_output_data( const Target* target, const char* name, const char* version, Output_data* od, typename elfcpp::Elf_types::Elf_Addr value, typename elfcpp::Elf_types::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* sym; Sized_symbol* oldsym; if (target->is_big_endian()) { #if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG) sym = this->define_special_symbol SELECT_SIZE_ENDIAN_NAME(size, true) ( target, &name, &version, only_if_ref, &oldsym SELECT_SIZE_ENDIAN(size, true)); #else gold_unreachable(); #endif } else { #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE) sym = this->define_special_symbol SELECT_SIZE_ENDIAN_NAME(size, false) ( target, &name, &version, only_if_ref, &oldsym SELECT_SIZE_ENDIAN(size, false)); #else gold_unreachable(); #endif } if (sym == NULL) return NULL; gold_assert(version == NULL || oldsym != NULL); sym->init(name, od, value, symsize, type, binding, visibility, nonvis, offset_is_from_end); if (oldsym != NULL && Symbol_table::should_override_with_special(oldsym)) oldsym->override_with_special(sym); return sym; } // Define a symbol based on an Output_segment. Symbol* Symbol_table::define_in_output_segment(const Target* target, const char* name, const char* version, 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) { gold_assert(target->get_size() == this->size_); if (this->size_ == 32) { #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) return this->do_define_in_output_segment<32>(target, name, version, os, value, symsize, type, binding, visibility, nonvis, offset_base, only_if_ref); #else gold_unreachable(); #endif } else if (this->size_ == 64) { #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) return this->do_define_in_output_segment<64>(target, name, version, 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 Sized_symbol* Symbol_table::do_define_in_output_segment( const Target* target, const char* name, const char* version, Output_segment* os, typename elfcpp::Elf_types::Elf_Addr value, typename elfcpp::Elf_types::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* sym; Sized_symbol* oldsym; if (target->is_big_endian()) sym = this->define_special_symbol SELECT_SIZE_ENDIAN_NAME(size, true) ( target, &name, &version, only_if_ref, &oldsym SELECT_SIZE_ENDIAN(size, true)); else sym = this->define_special_symbol SELECT_SIZE_ENDIAN_NAME(size, false) ( target, &name, &version, only_if_ref, &oldsym SELECT_SIZE_ENDIAN(size, false)); if (sym == NULL) return NULL; gold_assert(version == NULL || oldsym != NULL); sym->init(name, os, value, symsize, type, binding, visibility, nonvis, offset_base); if (oldsym != NULL && Symbol_table::should_override_with_special(oldsym)) oldsym->override_with_special(sym); return sym; } // 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 Target* target, const char* name, const char* version, uint64_t value, uint64_t symsize, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis, bool only_if_ref) { gold_assert(target->get_size() == this->size_); if (this->size_ == 32) { #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) return this->do_define_as_constant<32>(target, name, version, value, symsize, type, binding, visibility, nonvis, only_if_ref); #else gold_unreachable(); #endif } else if (this->size_ == 64) { #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) return this->do_define_as_constant<64>(target, name, version, value, symsize, type, binding, visibility, nonvis, only_if_ref); #else gold_unreachable(); #endif } else gold_unreachable(); } // Define a symbol as a constant, sized version. template Sized_symbol* Symbol_table::do_define_as_constant( const Target* target, const char* name, const char* version, typename elfcpp::Elf_types::Elf_Addr value, typename elfcpp::Elf_types::Elf_WXword symsize, elfcpp::STT type, elfcpp::STB binding, elfcpp::STV visibility, unsigned char nonvis, bool only_if_ref) { Sized_symbol* sym; Sized_symbol* oldsym; if (target->is_big_endian()) sym = this->define_special_symbol SELECT_SIZE_ENDIAN_NAME(size, true) ( target, &name, &version, only_if_ref, &oldsym SELECT_SIZE_ENDIAN(size, true)); else sym = this->define_special_symbol SELECT_SIZE_ENDIAN_NAME(size, false) ( target, &name, &version, only_if_ref, &oldsym SELECT_SIZE_ENDIAN(size, false)); if (sym == NULL) return NULL; gold_assert(version == NULL || oldsym != NULL); sym->init(name, value, symsize, type, binding, visibility, nonvis); if (oldsym != NULL && Symbol_table::should_override_with_special(oldsym)) oldsym->override_with_special(sym); return sym; } // Define a set of symbols in output sections. void Symbol_table::define_symbols(const Layout* layout, const Target* target, int count, const Define_symbol_in_section* p) { 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(target, p->name, NULL, os, p->value, p->size, p->type, p->binding, p->visibility, p->nonvis, p->offset_is_from_end, p->only_if_ref); else this->define_as_constant(target, p->name, NULL, 0, p->size, p->type, p->binding, p->visibility, p->nonvis, p->only_if_ref); } } // Define a set of symbols in output segments. void Symbol_table::define_symbols(const Layout* layout, const Target* target, int count, const Define_symbol_in_segment* p) { 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(target, p->name, NULL, os, p->value, p->size, p->type, p->binding, p->visibility, p->nonvis, p->offset_base, p->only_if_ref); else this->define_as_constant(target, p->name, NULL, 0, p->size, p->type, p->binding, p->visibility, p->nonvis, p->only_if_ref); } } // 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(const General_options* options, const Target* target, unsigned int index, std::vector* 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->needs_dynsym_entry() && (!options->export_dynamic() || !sym->in_reg() || !sym->is_externally_visible())) 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(), NULL); // Record any version information. if (sym->version() != NULL) versions->record_version(options, dynpool, sym); } } // Finish up the versions. In some cases this may add new dynamic // symbols. index = versions->finalize(target, 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 INDEX. Record the file offset // OFF. Add their names to POOL. Return the new file offset. off_t Symbol_table::finalize(unsigned int index, off_t off, off_t dynoff, size_t dyn_global_index, size_t dyncount, Stringpool* pool) { off_t ret; gold_assert(index != 0); this->first_global_index_ = index; this->dynamic_offset_ = dynoff; this->first_dynamic_global_index_ = dyn_global_index; this->dynamic_count_ = dyncount; if (this->size_ == 32) ret = this->sized_finalize<32>(index, off, pool); else if (this->size_ == 64) ret = this->sized_finalize<64>(index, off, pool); 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; } // Set the final value for all the symbols. This is called after // Layout::finalize, so all the output sections have their final // address. template off_t Symbol_table::sized_finalize(unsigned index, off_t off, Stringpool* pool) { off = align_address(off, size >> 3); this->offset_ = off; size_t orig_index = index; const int sym_size = elfcpp::Elf_sizes::sym_size; for (Symbol_table_type::iterator p = this->table_.begin(); p != this->table_.end(); ++p) { Sized_symbol* sym = static_cast*>(p->second); // FIXME: Here we need to decide which symbols should go into // the output file, based on --strip. // 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()) continue; if (!sym->in_reg()) { gold_assert(!sym->has_symtab_index()); sym->set_symtab_index(-1U); gold_assert(sym->dynsym_index() == -1U); continue; } typename Sized_symbol::Value_type value; switch (sym->source()) { case Symbol::FROM_OBJECT: { unsigned int shndx = sym->shndx(); // FIXME: We need some target specific support here. if (shndx >= elfcpp::SHN_LORESERVE && shndx != elfcpp::SHN_ABS) { fprintf(stderr, _("%s: %s: unsupported symbol section 0x%x\n"), program_name, sym->name(), shndx); gold_exit(false); } Object* symobj = sym->object(); if (symobj->is_dynamic()) { value = 0; shndx = elfcpp::SHN_UNDEF; } else if (shndx == elfcpp::SHN_UNDEF) value = 0; else if (shndx == elfcpp::SHN_ABS) value = sym->value(); else { Relobj* relobj = static_cast(symobj); off_t secoff; Output_section* os = relobj->output_section(shndx, &secoff); if (os == NULL) { sym->set_symtab_index(-1U); gold_assert(sym->dynsym_index() == -1U); continue; } value = sym->value() + os->address() + secoff; } } break; case Symbol::IN_OUTPUT_DATA: { Output_data* od = sym->output_data(); value = sym->value() + od->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() + 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::CONSTANT: value = sym->value(); break; default: gold_unreachable(); } sym->set_value(value); sym->set_symtab_index(index); pool->add(sym->name(), NULL); ++index; off += sym_size; } this->output_count_ = index - orig_index; return off; } // Write out the global symbols. void Symbol_table::write_globals(const Target* target, const Stringpool* sympool, const Stringpool* dynpool, Output_file* of) const { if (this->size_ == 32) { if (target->is_big_endian()) this->sized_write_globals<32, true>(target, sympool, dynpool, of); else this->sized_write_globals<32, false>(target, sympool, dynpool, of); } else if (this->size_ == 64) { if (target->is_big_endian()) this->sized_write_globals<64, true>(target, sympool, dynpool, of); else this->sized_write_globals<64, false>(target, sympool, dynpool, of); } else gold_unreachable(); } // Write out the global symbols. template void Symbol_table::sized_write_globals(const Target* target, const Stringpool* sympool, const Stringpool* dynpool, Output_file* of) const { const int sym_size = elfcpp::Elf_sizes::sym_size; unsigned int index = this->first_global_index_; const off_t oview_size = this->output_count_ * sym_size; unsigned char* const psyms = of->get_output_view(this->offset_, oview_size); unsigned int dynamic_count = this->dynamic_count_; off_t dynamic_size = dynamic_count * sym_size; unsigned int first_dynamic_global_index = this->first_dynamic_global_index_; unsigned char* dynamic_view; if (this->dynamic_offset_ == 0) dynamic_view = NULL; else dynamic_view = of->get_output_view(this->dynamic_offset_, dynamic_size); unsigned char* ps = psyms; for (Symbol_table_type::const_iterator p = this->table_.begin(); p != this->table_.end(); ++p) { Sized_symbol* sym = static_cast*>(p->second); 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; } if (sym_index == index) ++index; else if (sym_index != -1U) { // We have already seen this symbol, because it has a // default version. gold_assert(sym_index < index); if (dynsym_index == -1U) continue; sym_index = -1U; } unsigned int shndx; typename elfcpp::Elf_types<32>::Elf_Addr value = sym->value(); switch (sym->source()) { case Symbol::FROM_OBJECT: { unsigned int in_shndx = sym->shndx(); // FIXME: We need some target specific support here. if (in_shndx >= elfcpp::SHN_LORESERVE && in_shndx != elfcpp::SHN_ABS) { fprintf(stderr, _("%s: %s: unsupported symbol section 0x%x\n"), program_name, sym->name(), in_shndx); gold_exit(false); } Object* symobj = sym->object(); if (symobj->is_dynamic()) { if (sym->needs_dynsym_value()) value = target->dynsym_value(sym); shndx = elfcpp::SHN_UNDEF; } else if (in_shndx == elfcpp::SHN_UNDEF || in_shndx == elfcpp::SHN_ABS) shndx = in_shndx; else { Relobj* relobj = static_cast(symobj); off_t secoff; Output_section* os = relobj->output_section(in_shndx, &secoff); gold_assert(os != NULL); shndx = os->out_shndx(); } } break; case Symbol::IN_OUTPUT_DATA: shndx = sym->output_data()->out_shndx(); break; case Symbol::IN_OUTPUT_SEGMENT: shndx = elfcpp::SHN_ABS; break; case Symbol::CONSTANT: shndx = elfcpp::SHN_ABS; break; default: gold_unreachable(); } if (sym_index != -1U) { this->sized_write_symbol SELECT_SIZE_ENDIAN_NAME(size, big_endian) ( sym, sym->value(), shndx, sympool, ps SELECT_SIZE_ENDIAN(size, big_endian)); ps += sym_size; } 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 SELECT_SIZE_ENDIAN_NAME(size, big_endian) ( sym, value, shndx, dynpool, pd SELECT_SIZE_ENDIAN(size, big_endian)); } } gold_assert(ps - psyms == oview_size); 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 void Symbol_table::sized_write_symbol( Sized_symbol* sym, typename elfcpp::Elf_types::Elf_Addr value, unsigned int shndx, const Stringpool* pool, unsigned char* p ACCEPT_SIZE_ENDIAN) const { elfcpp::Sym_write osym(p); osym.put_st_name(pool->get_offset(sym->name())); osym.put_st_value(value); osym.put_st_size(sym->symsize()); osym.put_st_info(elfcpp::elf_st_info(sym->binding(), sym->type())); osym.put_st_other(elfcpp::elf_st_other(sym->visibility(), sym->nonvis())); osym.put_st_shndx(shndx); } // Write out a section symbol. Return the update offset. void Symbol_table::write_section_symbol(const Target* target, const Output_section *os, Output_file* of, off_t offset) const { if (this->size_ == 32) { if (target->is_big_endian()) this->sized_write_section_symbol<32, true>(os, of, offset); else this->sized_write_section_symbol<32, false>(os, of, offset); } else if (this->size_ == 64) { if (target->is_big_endian()) this->sized_write_section_symbol<64, true>(os, of, offset); else this->sized_write_section_symbol<64, false>(os, of, offset); } else gold_unreachable(); } // Write out a section symbol, specialized for size and endianness. template void Symbol_table::sized_write_section_symbol(const Output_section* os, Output_file* of, off_t offset) const { const int sym_size = elfcpp::Elf_sizes::sym_size; unsigned char* pov = of->get_output_view(offset, sym_size); elfcpp::Sym_write osym(pov); osym.put_st_name(0); 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)); osym.put_st_shndx(os->out_shndx()); of->write_output_view(offset, sym_size, pov); } // Warnings functions. // Add a new warning. void Warnings::add_warning(Symbol_table* symtab, const char* name, Object* obj, unsigned int shndx) { name = symtab->canonicalize_name(name); this->warnings_[name].set(obj, shndx); } // 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(); // Read the section contents to get the warning text. It // would be nicer if we only did this if we have to actually // issue a warning. Unfortunately, warnings are issued as // we relocate sections. That means that we can not lock // the object then, as we might try to issue the same // warning multiple times simultaneously. { Task_locker_obj tl(*p->second.object); const unsigned char* c; off_t len; c = p->second.object->section_contents(p->second.shndx, &len); p->second.set_text(reinterpret_cast(c), len); } } } } // Issue a warning. This is called when we see a relocation against a // symbol for which has a warning. void Warnings::issue_warning(const Symbol* sym, const std::string& location) const { gold_assert(sym->has_warning()); Warning_table::const_iterator p = this->warnings_.find(sym->name()); gold_assert(p != this->warnings_.end()); fprintf(stderr, _("%s: %s: warning: %s\n"), program_name, location.c_str(), 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. #ifdef HAVE_TARGET_32_LITTLE template void Symbol_table::add_from_relobj<32, false>( Sized_relobj<32, false>* relobj, const unsigned char* syms, size_t count, const char* sym_names, size_t sym_name_size, Symbol** sympointers); #endif #ifdef HAVE_TARGET_32_BIG template void Symbol_table::add_from_relobj<32, true>( Sized_relobj<32, true>* relobj, const unsigned char* syms, size_t count, const char* sym_names, size_t sym_name_size, Symbol** sympointers); #endif #ifdef HAVE_TARGET_64_LITTLE template void Symbol_table::add_from_relobj<64, false>( Sized_relobj<64, false>* relobj, const unsigned char* syms, size_t count, const char* sym_names, size_t sym_name_size, Symbol** sympointers); #endif #ifdef HAVE_TARGET_64_BIG template void Symbol_table::add_from_relobj<64, true>( Sized_relobj<64, true>* relobj, const unsigned char* syms, size_t count, const char* sym_names, size_t sym_name_size, Symbol** sympointers); #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* version_map); #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* version_map); #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* version_map); #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* version_map); #endif } // End namespace gold.