// resolve.cc -- symbol resolution for gold // Copyright 2006, 2007, 2008, 2009, 2010 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 "elfcpp.h" #include "target.h" #include "object.h" #include "symtab.h" #include "plugin.h" namespace gold { // Symbol methods used in this file. // This symbol is being overridden by another symbol whose version is // VERSION. Update the VERSION_ field accordingly. inline void Symbol::override_version(const char* version) { if (version == NULL) { // This is the case where this symbol is NAME/VERSION, and the // version was not marked as hidden. That makes it the default // version, so we create NAME/NULL. Later we see another symbol // NAME/NULL, and that symbol is overriding this one. In this // case, since NAME/VERSION is the default, we make NAME/NULL // override NAME/VERSION as well. They are already the same // Symbol structure. Setting the VERSION_ field to NULL ensures // that it will be output with the correct, empty, version. this->version_ = version; } else { // This is the case where this symbol is NAME/VERSION_ONE, and // now we see NAME/VERSION_TWO, and NAME/VERSION_TWO is // overriding NAME. If VERSION_ONE and VERSION_TWO are // different, then this can only happen when VERSION_ONE is NULL // and VERSION_TWO is not hidden. gold_assert(this->version_ == version || this->version_ == NULL); this->version_ = version; } } // This symbol is being overidden by another symbol whose visibility // is VISIBILITY. Updated the VISIBILITY_ field accordingly. inline void Symbol::override_visibility(elfcpp::STV visibility) { // The rule for combining visibility is that we always choose the // most constrained visibility. In order of increasing constraint, // visibility goes PROTECTED, HIDDEN, INTERNAL. This is the reverse // of the numeric values, so the effect is that we always want the // smallest non-zero value. if (visibility != elfcpp::STV_DEFAULT) { if (this->visibility_ == elfcpp::STV_DEFAULT) this->visibility_ = visibility; else if (this->visibility_ > visibility) this->visibility_ = visibility; } } // Override the fields in Symbol. template void Symbol::override_base(const elfcpp::Sym& sym, unsigned int st_shndx, bool is_ordinary, Object* object, const char* version) { gold_assert(this->source_ == FROM_OBJECT); this->u_.from_object.object = object; this->override_version(version); this->u_.from_object.shndx = st_shndx; this->is_ordinary_shndx_ = is_ordinary; this->type_ = sym.get_st_type(); this->binding_ = sym.get_st_bind(); this->override_visibility(sym.get_st_visibility()); this->nonvis_ = sym.get_st_nonvis(); if (object->is_dynamic()) this->in_dyn_ = true; else this->in_reg_ = true; } // Override the fields in Sized_symbol. template template void Sized_symbol::override(const elfcpp::Sym& sym, unsigned st_shndx, bool is_ordinary, Object* object, const char* version) { this->override_base(sym, st_shndx, is_ordinary, object, version); this->value_ = sym.get_st_value(); this->symsize_ = sym.get_st_size(); } // Override TOSYM with symbol FROMSYM, defined in OBJECT, with version // VERSION. This handles all aliases of TOSYM. template void Symbol_table::override(Sized_symbol* tosym, const elfcpp::Sym& fromsym, unsigned int st_shndx, bool is_ordinary, Object* object, const char* version) { tosym->override(fromsym, st_shndx, is_ordinary, object, version); if (tosym->has_alias()) { Symbol* sym = this->weak_aliases_[tosym]; gold_assert(sym != NULL); Sized_symbol* ssym = this->get_sized_symbol(sym); do { ssym->override(fromsym, st_shndx, is_ordinary, object, version); sym = this->weak_aliases_[ssym]; gold_assert(sym != NULL); ssym = this->get_sized_symbol(sym); } while (ssym != tosym); } } // The resolve functions build a little code for each symbol. // Bit 0: 0 for global, 1 for weak. // Bit 1: 0 for regular object, 1 for shared object // Bits 2-3: 0 for normal, 1 for undefined, 2 for common // This gives us values from 0 to 11. static const int global_or_weak_shift = 0; static const unsigned int global_flag = 0 << global_or_weak_shift; static const unsigned int weak_flag = 1 << global_or_weak_shift; static const int regular_or_dynamic_shift = 1; static const unsigned int regular_flag = 0 << regular_or_dynamic_shift; static const unsigned int dynamic_flag = 1 << regular_or_dynamic_shift; static const int def_undef_or_common_shift = 2; static const unsigned int def_flag = 0 << def_undef_or_common_shift; static const unsigned int undef_flag = 1 << def_undef_or_common_shift; static const unsigned int common_flag = 2 << def_undef_or_common_shift; // This convenience function combines all the flags based on facts // about the symbol. static unsigned int symbol_to_bits(elfcpp::STB binding, bool is_dynamic, unsigned int shndx, bool is_ordinary, elfcpp::STT type) { unsigned int bits; switch (binding) { case elfcpp::STB_GLOBAL: case elfcpp::STB_GNU_UNIQUE: bits = global_flag; break; case elfcpp::STB_WEAK: bits = weak_flag; break; case elfcpp::STB_LOCAL: // We should only see externally visible symbols in the symbol // table. gold_error(_("invalid STB_LOCAL symbol in external symbols")); bits = global_flag; default: // Any target which wants to handle STB_LOOS, etc., needs to // define a resolve method. gold_error(_("unsupported symbol binding %d"), static_cast(binding)); bits = global_flag; } if (is_dynamic) bits |= dynamic_flag; else bits |= regular_flag; switch (shndx) { case elfcpp::SHN_UNDEF: bits |= undef_flag; break; case elfcpp::SHN_COMMON: if (!is_ordinary) bits |= common_flag; break; default: if (type == elfcpp::STT_COMMON) bits |= common_flag; else if (!is_ordinary && Symbol::is_common_shndx(shndx)) bits |= common_flag; else bits |= def_flag; break; } return bits; } // Resolve a symbol. This is called the second and subsequent times // we see a symbol. TO is the pre-existing symbol. ST_SHNDX is the // section index for SYM, possibly adjusted for many sections. // IS_ORDINARY is whether ST_SHNDX is a normal section index rather // than a special code. ORIG_ST_SHNDX is the original section index, // before any munging because of discarded sections, except that all // non-ordinary section indexes are mapped to SHN_UNDEF. VERSION is // the version of SYM. template void Symbol_table::resolve(Sized_symbol* to, const elfcpp::Sym& sym, unsigned int st_shndx, bool is_ordinary, unsigned int orig_st_shndx, Object* object, const char* version) { if (parameters->target().has_resolve()) { Sized_target* sized_target; sized_target = parameters->sized_target(); sized_target->resolve(to, sym, object, version); return; } if (!object->is_dynamic()) { // Record that we've seen this symbol in a regular object. to->set_in_reg(); } else if (st_shndx == elfcpp::SHN_UNDEF && (to->visibility() == elfcpp::STV_HIDDEN || to->visibility() == elfcpp::STV_INTERNAL)) { // A dynamic object cannot reference a hidden or internal symbol // defined in another object. gold_warning(_("%s symbol '%s' in %s is referenced by DSO %s"), (to->visibility() == elfcpp::STV_HIDDEN ? "hidden" : "internal"), to->demangled_name().c_str(), to->object()->name().c_str(), object->name().c_str()); return; } else { // Record that we've seen this symbol in a dynamic object. to->set_in_dyn(); } // Record if we've seen this symbol in a real ELF object (i.e., the // symbol is referenced from outside the world known to the plugin). if (object->pluginobj() == NULL) to->set_in_real_elf(); // If we're processing replacement files, allow new symbols to override // the placeholders from the plugin objects. if (to->source() == Symbol::FROM_OBJECT) { Pluginobj* obj = to->object()->pluginobj(); if (obj != NULL && parameters->options().plugins()->in_replacement_phase()) { this->override(to, sym, st_shndx, is_ordinary, object, version); return; } } // A new weak undefined reference, merging with an old weak // reference, could be a One Definition Rule (ODR) violation -- // especially if the types or sizes of the references differ. We'll // store such pairs and look them up later to make sure they // actually refer to the same lines of code. We also check // combinations of weak and strong, which might occur if one case is // inline and the other is not. (Note: not all ODR violations can // be found this way, and not everything this finds is an ODR // violation. But it's helpful to warn about.) bool to_is_ordinary; if (parameters->options().detect_odr_violations() && (sym.get_st_bind() == elfcpp::STB_WEAK || to->binding() == elfcpp::STB_WEAK) && orig_st_shndx != elfcpp::SHN_UNDEF && to->shndx(&to_is_ordinary) != elfcpp::SHN_UNDEF && to_is_ordinary && sym.get_st_size() != 0 // Ignore weird 0-sized symbols. && to->symsize() != 0 && (sym.get_st_type() != to->type() || sym.get_st_size() != to->symsize()) // C does not have a concept of ODR, so we only need to do this // on C++ symbols. These have (mangled) names starting with _Z. && to->name()[0] == '_' && to->name()[1] == 'Z') { Symbol_location fromloc = { object, orig_st_shndx, sym.get_st_value() }; Symbol_location toloc = { to->object(), to->shndx(&to_is_ordinary), to->value() }; this->candidate_odr_violations_[to->name()].insert(fromloc); this->candidate_odr_violations_[to->name()].insert(toloc); } unsigned int frombits = symbol_to_bits(sym.get_st_bind(), object->is_dynamic(), st_shndx, is_ordinary, sym.get_st_type()); bool adjust_common_sizes; bool adjust_dyndef; typename Sized_symbol::Size_type tosize = to->symsize(); if (Symbol_table::should_override(to, frombits, OBJECT, object, &adjust_common_sizes, &adjust_dyndef)) { elfcpp::STB tobinding = to->binding(); this->override(to, sym, st_shndx, is_ordinary, object, version); if (adjust_common_sizes && tosize > to->symsize()) to->set_symsize(tosize); if (adjust_dyndef) { // We are overriding an UNDEF or WEAK UNDEF with a DYN DEF. // Remember which kind of UNDEF it was for future reference. to->set_undef_binding(tobinding); } } else { if (adjust_common_sizes && sym.get_st_size() > tosize) to->set_symsize(sym.get_st_size()); if (adjust_dyndef) { // We are keeping a DYN DEF after seeing an UNDEF or WEAK UNDEF. // Remember which kind of UNDEF it was. to->set_undef_binding(sym.get_st_bind()); } // The ELF ABI says that even for a reference to a symbol we // merge the visibility. to->override_visibility(sym.get_st_visibility()); } if (adjust_common_sizes && parameters->options().warn_common()) { if (tosize > sym.get_st_size()) Symbol_table::report_resolve_problem(false, _("common of '%s' overriding " "smaller common"), to, OBJECT, object); else if (tosize < sym.get_st_size()) Symbol_table::report_resolve_problem(false, _("common of '%s' overidden by " "larger common"), to, OBJECT, object); else Symbol_table::report_resolve_problem(false, _("multiple common of '%s'"), to, OBJECT, object); } } // Handle the core of symbol resolution. This is called with the // existing symbol, TO, and a bitflag describing the new symbol. This // returns true if we should override the existing symbol with the new // one, and returns false otherwise. It sets *ADJUST_COMMON_SIZES to // true if we should set the symbol size to the maximum of the TO and // FROM sizes. It handles error conditions. bool Symbol_table::should_override(const Symbol* to, unsigned int frombits, Defined defined, Object* object, bool* adjust_common_sizes, bool* adjust_dyndef) { *adjust_common_sizes = false; *adjust_dyndef = false; unsigned int tobits; if (to->source() == Symbol::IS_UNDEFINED) tobits = symbol_to_bits(to->binding(), false, elfcpp::SHN_UNDEF, true, to->type()); else if (to->source() != Symbol::FROM_OBJECT) tobits = symbol_to_bits(to->binding(), false, elfcpp::SHN_ABS, false, to->type()); else { bool is_ordinary; unsigned int shndx = to->shndx(&is_ordinary); tobits = symbol_to_bits(to->binding(), to->object()->is_dynamic(), shndx, is_ordinary, to->type()); } // FIXME: Warn if either but not both of TO and SYM are STT_TLS. // We use a giant switch table for symbol resolution. This code is // unwieldy, but: 1) it is efficient; 2) we definitely handle all // cases; 3) it is easy to change the handling of a particular case. // The alternative would be a series of conditionals, but it is easy // to get the ordering wrong. This could also be done as a table, // but that is no easier to understand than this large switch // statement. // These are the values generated by the bit codes. enum { DEF = global_flag | regular_flag | def_flag, WEAK_DEF = weak_flag | regular_flag | def_flag, DYN_DEF = global_flag | dynamic_flag | def_flag, DYN_WEAK_DEF = weak_flag | dynamic_flag | def_flag, UNDEF = global_flag | regular_flag | undef_flag, WEAK_UNDEF = weak_flag | regular_flag | undef_flag, DYN_UNDEF = global_flag | dynamic_flag | undef_flag, DYN_WEAK_UNDEF = weak_flag | dynamic_flag | undef_flag, COMMON = global_flag | regular_flag | common_flag, WEAK_COMMON = weak_flag | regular_flag | common_flag, DYN_COMMON = global_flag | dynamic_flag | common_flag, DYN_WEAK_COMMON = weak_flag | dynamic_flag | common_flag }; switch (tobits * 16 + frombits) { case DEF * 16 + DEF: // Two definitions of the same symbol. // If either symbol is defined by an object included using // --just-symbols, then don't warn. This is for compatibility // with the GNU linker. FIXME: This is a hack. if ((to->source() == Symbol::FROM_OBJECT && to->object()->just_symbols()) || (object != NULL && object->just_symbols())) return false; if (!parameters->options().muldefs()) Symbol_table::report_resolve_problem(true, _("multiple definition of '%s'"), to, defined, object); return false; case WEAK_DEF * 16 + DEF: // We've seen a weak definition, and now we see a strong // definition. In the original SVR4 linker, this was treated as // a multiple definition error. In the Solaris linker and the // GNU linker, a weak definition followed by a regular // definition causes the weak definition to be overridden. We // are currently compatible with the GNU linker. In the future // we should add a target specific option to change this. // FIXME. return true; case DYN_DEF * 16 + DEF: case DYN_WEAK_DEF * 16 + DEF: // We've seen a definition in a dynamic object, and now we see a // definition in a regular object. The definition in the // regular object overrides the definition in the dynamic // object. return true; case UNDEF * 16 + DEF: case WEAK_UNDEF * 16 + DEF: case DYN_UNDEF * 16 + DEF: case DYN_WEAK_UNDEF * 16 + DEF: // We've seen an undefined reference, and now we see a // definition. We use the definition. return true; case COMMON * 16 + DEF: case WEAK_COMMON * 16 + DEF: case DYN_COMMON * 16 + DEF: case DYN_WEAK_COMMON * 16 + DEF: // We've seen a common symbol and now we see a definition. The // definition overrides. if (parameters->options().warn_common()) Symbol_table::report_resolve_problem(false, _("definition of '%s' overriding " "common"), to, defined, object); return true; case DEF * 16 + WEAK_DEF: case WEAK_DEF * 16 + WEAK_DEF: // We've seen a definition and now we see a weak definition. We // ignore the new weak definition. return false; case DYN_DEF * 16 + WEAK_DEF: case DYN_WEAK_DEF * 16 + WEAK_DEF: // We've seen a dynamic definition and now we see a regular weak // definition. The regular weak definition overrides. return true; case UNDEF * 16 + WEAK_DEF: case WEAK_UNDEF * 16 + WEAK_DEF: case DYN_UNDEF * 16 + WEAK_DEF: case DYN_WEAK_UNDEF * 16 + WEAK_DEF: // A weak definition of a currently undefined symbol. return true; case COMMON * 16 + WEAK_DEF: case WEAK_COMMON * 16 + WEAK_DEF: // A weak definition does not override a common definition. return false; case DYN_COMMON * 16 + WEAK_DEF: case DYN_WEAK_COMMON * 16 + WEAK_DEF: // A weak definition does override a definition in a dynamic // object. if (parameters->options().warn_common()) Symbol_table::report_resolve_problem(false, _("definition of '%s' overriding " "dynamic common definition"), to, defined, object); return true; case DEF * 16 + DYN_DEF: case WEAK_DEF * 16 + DYN_DEF: case DYN_DEF * 16 + DYN_DEF: case DYN_WEAK_DEF * 16 + DYN_DEF: // Ignore a dynamic definition if we already have a definition. return false; case UNDEF * 16 + DYN_DEF: case DYN_UNDEF * 16 + DYN_DEF: case DYN_WEAK_UNDEF * 16 + DYN_DEF: // Use a dynamic definition if we have a reference. return true; case WEAK_UNDEF * 16 + DYN_DEF: // When overriding a weak undef by a dynamic definition, // we need to remember that the original undef was weak. *adjust_dyndef = true; return true; case COMMON * 16 + DYN_DEF: case WEAK_COMMON * 16 + DYN_DEF: case DYN_COMMON * 16 + DYN_DEF: case DYN_WEAK_COMMON * 16 + DYN_DEF: // Ignore a dynamic definition if we already have a common // definition. return false; case DEF * 16 + DYN_WEAK_DEF: case WEAK_DEF * 16 + DYN_WEAK_DEF: case DYN_DEF * 16 + DYN_WEAK_DEF: case DYN_WEAK_DEF * 16 + DYN_WEAK_DEF: // Ignore a weak dynamic definition if we already have a // definition. return false; case UNDEF * 16 + DYN_WEAK_DEF: // When overriding an undef by a dynamic weak definition, // we need to remember that the original undef was not weak. *adjust_dyndef = true; return true; case DYN_UNDEF * 16 + DYN_WEAK_DEF: case DYN_WEAK_UNDEF * 16 + DYN_WEAK_DEF: // Use a weak dynamic definition if we have a reference. return true; case WEAK_UNDEF * 16 + DYN_WEAK_DEF: // When overriding a weak undef by a dynamic definition, // we need to remember that the original undef was weak. *adjust_dyndef = true; return true; case COMMON * 16 + DYN_WEAK_DEF: case WEAK_COMMON * 16 + DYN_WEAK_DEF: case DYN_COMMON * 16 + DYN_WEAK_DEF: case DYN_WEAK_COMMON * 16 + DYN_WEAK_DEF: // Ignore a weak dynamic definition if we already have a common // definition. return false; case DEF * 16 + UNDEF: case WEAK_DEF * 16 + UNDEF: case UNDEF * 16 + UNDEF: // A new undefined reference tells us nothing. return false; case DYN_DEF * 16 + UNDEF: case DYN_WEAK_DEF * 16 + UNDEF: // For a dynamic def, we need to remember which kind of undef we see. *adjust_dyndef = true; return false; case WEAK_UNDEF * 16 + UNDEF: case DYN_UNDEF * 16 + UNDEF: case DYN_WEAK_UNDEF * 16 + UNDEF: // A strong undef overrides a dynamic or weak undef. return true; case COMMON * 16 + UNDEF: case WEAK_COMMON * 16 + UNDEF: case DYN_COMMON * 16 + UNDEF: case DYN_WEAK_COMMON * 16 + UNDEF: // A new undefined reference tells us nothing. return false; case DEF * 16 + WEAK_UNDEF: case WEAK_DEF * 16 + WEAK_UNDEF: case UNDEF * 16 + WEAK_UNDEF: case WEAK_UNDEF * 16 + WEAK_UNDEF: case DYN_UNDEF * 16 + WEAK_UNDEF: case COMMON * 16 + WEAK_UNDEF: case WEAK_COMMON * 16 + WEAK_UNDEF: case DYN_COMMON * 16 + WEAK_UNDEF: case DYN_WEAK_COMMON * 16 + WEAK_UNDEF: // A new weak undefined reference tells us nothing unless the // exisiting symbol is a dynamic weak reference. return false; case DYN_WEAK_UNDEF * 16 + WEAK_UNDEF: // A new weak reference overrides an existing dynamic weak reference. // This is necessary because a dynamic weak reference remembers // the old binding, which may not be weak. If we keeps the existing // dynamic weak reference, the weakness may be dropped in the output. return true; case DYN_DEF * 16 + WEAK_UNDEF: case DYN_WEAK_DEF * 16 + WEAK_UNDEF: // For a dynamic def, we need to remember which kind of undef we see. *adjust_dyndef = true; return false; case DEF * 16 + DYN_UNDEF: case WEAK_DEF * 16 + DYN_UNDEF: case DYN_DEF * 16 + DYN_UNDEF: case DYN_WEAK_DEF * 16 + DYN_UNDEF: case UNDEF * 16 + DYN_UNDEF: case WEAK_UNDEF * 16 + DYN_UNDEF: case DYN_UNDEF * 16 + DYN_UNDEF: case DYN_WEAK_UNDEF * 16 + DYN_UNDEF: case COMMON * 16 + DYN_UNDEF: case WEAK_COMMON * 16 + DYN_UNDEF: case DYN_COMMON * 16 + DYN_UNDEF: case DYN_WEAK_COMMON * 16 + DYN_UNDEF: // A new dynamic undefined reference tells us nothing. return false; case DEF * 16 + DYN_WEAK_UNDEF: case WEAK_DEF * 16 + DYN_WEAK_UNDEF: case DYN_DEF * 16 + DYN_WEAK_UNDEF: case DYN_WEAK_DEF * 16 + DYN_WEAK_UNDEF: case UNDEF * 16 + DYN_WEAK_UNDEF: case WEAK_UNDEF * 16 + DYN_WEAK_UNDEF: case DYN_UNDEF * 16 + DYN_WEAK_UNDEF: case DYN_WEAK_UNDEF * 16 + DYN_WEAK_UNDEF: case COMMON * 16 + DYN_WEAK_UNDEF: case WEAK_COMMON * 16 + DYN_WEAK_UNDEF: case DYN_COMMON * 16 + DYN_WEAK_UNDEF: case DYN_WEAK_COMMON * 16 + DYN_WEAK_UNDEF: // A new weak dynamic undefined reference tells us nothing. return false; case DEF * 16 + COMMON: // A common symbol does not override a definition. if (parameters->options().warn_common()) Symbol_table::report_resolve_problem(false, _("common '%s' overridden by " "previous definition"), to, defined, object); return false; case WEAK_DEF * 16 + COMMON: case DYN_DEF * 16 + COMMON: case DYN_WEAK_DEF * 16 + COMMON: // A common symbol does override a weak definition or a dynamic // definition. return true; case UNDEF * 16 + COMMON: case WEAK_UNDEF * 16 + COMMON: case DYN_UNDEF * 16 + COMMON: case DYN_WEAK_UNDEF * 16 + COMMON: // A common symbol is a definition for a reference. return true; case COMMON * 16 + COMMON: // Set the size to the maximum. *adjust_common_sizes = true; return false; case WEAK_COMMON * 16 + COMMON: // I'm not sure just what a weak common symbol means, but // presumably it can be overridden by a regular common symbol. return true; case DYN_COMMON * 16 + COMMON: case DYN_WEAK_COMMON * 16 + COMMON: // Use the real common symbol, but adjust the size if necessary. *adjust_common_sizes = true; return true; case DEF * 16 + WEAK_COMMON: case WEAK_DEF * 16 + WEAK_COMMON: case DYN_DEF * 16 + WEAK_COMMON: case DYN_WEAK_DEF * 16 + WEAK_COMMON: // Whatever a weak common symbol is, it won't override a // definition. return false; case UNDEF * 16 + WEAK_COMMON: case WEAK_UNDEF * 16 + WEAK_COMMON: case DYN_UNDEF * 16 + WEAK_COMMON: case DYN_WEAK_UNDEF * 16 + WEAK_COMMON: // A weak common symbol is better than an undefined symbol. return true; case COMMON * 16 + WEAK_COMMON: case WEAK_COMMON * 16 + WEAK_COMMON: case DYN_COMMON * 16 + WEAK_COMMON: case DYN_WEAK_COMMON * 16 + WEAK_COMMON: // Ignore a weak common symbol in the presence of a real common // symbol. return false; case DEF * 16 + DYN_COMMON: case WEAK_DEF * 16 + DYN_COMMON: case DYN_DEF * 16 + DYN_COMMON: case DYN_WEAK_DEF * 16 + DYN_COMMON: // Ignore a dynamic common symbol in the presence of a // definition. return false; case UNDEF * 16 + DYN_COMMON: case WEAK_UNDEF * 16 + DYN_COMMON: case DYN_UNDEF * 16 + DYN_COMMON: case DYN_WEAK_UNDEF * 16 + DYN_COMMON: // A dynamic common symbol is a definition of sorts. return true; case COMMON * 16 + DYN_COMMON: case WEAK_COMMON * 16 + DYN_COMMON: case DYN_COMMON * 16 + DYN_COMMON: case DYN_WEAK_COMMON * 16 + DYN_COMMON: // Set the size to the maximum. *adjust_common_sizes = true; return false; case DEF * 16 + DYN_WEAK_COMMON: case WEAK_DEF * 16 + DYN_WEAK_COMMON: case DYN_DEF * 16 + DYN_WEAK_COMMON: case DYN_WEAK_DEF * 16 + DYN_WEAK_COMMON: // A common symbol is ignored in the face of a definition. return false; case UNDEF * 16 + DYN_WEAK_COMMON: case WEAK_UNDEF * 16 + DYN_WEAK_COMMON: case DYN_UNDEF * 16 + DYN_WEAK_COMMON: case DYN_WEAK_UNDEF * 16 + DYN_WEAK_COMMON: // I guess a weak common symbol is better than a definition. return true; case COMMON * 16 + DYN_WEAK_COMMON: case WEAK_COMMON * 16 + DYN_WEAK_COMMON: case DYN_COMMON * 16 + DYN_WEAK_COMMON: case DYN_WEAK_COMMON * 16 + DYN_WEAK_COMMON: // Set the size to the maximum. *adjust_common_sizes = true; return false; default: gold_unreachable(); } } // Issue an error or warning due to symbol resolution. IS_ERROR // indicates an error rather than a warning. MSG is the error // message; it is expected to have a %s for the symbol name. TO is // the existing symbol. DEFINED/OBJECT is where the new symbol was // found. // FIXME: We should have better location information here. When the // symbol is defined, we should be able to pull the location from the // debug info if there is any. void Symbol_table::report_resolve_problem(bool is_error, const char* msg, const Symbol* to, Defined defined, Object* object) { std::string demangled(to->demangled_name()); size_t len = strlen(msg) + demangled.length() + 10; char* buf = new char[len]; snprintf(buf, len, msg, demangled.c_str()); const char* objname; switch (defined) { case OBJECT: objname = object->name().c_str(); break; case COPY: objname = _("COPY reloc"); break; case DEFSYM: case UNDEFINED: objname = _("command line"); break; case SCRIPT: objname = _("linker script"); break; case PREDEFINED: case INCREMENTAL_BASE: objname = _("linker defined"); break; default: gold_unreachable(); } if (is_error) gold_error("%s: %s", objname, buf); else gold_warning("%s: %s", objname, buf); delete[] buf; if (to->source() == Symbol::FROM_OBJECT) objname = to->object()->name().c_str(); else objname = _("command line"); gold_info("%s: %s: previous definition here", program_name, objname); } // A special case of should_override which is only called for a strong // defined symbol from a regular object file. This is used when // defining special symbols. bool Symbol_table::should_override_with_special(const Symbol* to, Defined defined) { bool adjust_common_sizes; bool adjust_dyn_def; unsigned int frombits = global_flag | regular_flag | def_flag; bool ret = Symbol_table::should_override(to, frombits, defined, NULL, &adjust_common_sizes, &adjust_dyn_def); gold_assert(!adjust_common_sizes && !adjust_dyn_def); return ret; } // Override symbol base with a special symbol. void Symbol::override_base_with_special(const Symbol* from) { gold_assert(this->name_ == from->name_ || this->has_alias()); this->source_ = from->source_; switch (from->source_) { case FROM_OBJECT: this->u_.from_object = from->u_.from_object; break; case IN_OUTPUT_DATA: this->u_.in_output_data = from->u_.in_output_data; break; case IN_OUTPUT_SEGMENT: this->u_.in_output_segment = from->u_.in_output_segment; break; case IS_CONSTANT: case IS_UNDEFINED: break; default: gold_unreachable(); break; } this->override_version(from->version_); this->type_ = from->type_; this->binding_ = from->binding_; this->override_visibility(from->visibility_); this->nonvis_ = from->nonvis_; // Special symbols are always considered to be regular symbols. this->in_reg_ = true; if (from->needs_dynsym_entry_) this->needs_dynsym_entry_ = true; if (from->needs_dynsym_value_) this->needs_dynsym_value_ = true; this->is_predefined_ = from->is_predefined_; // We shouldn't see these flags. If we do, we need to handle them // somehow. gold_assert(!from->is_forwarder_); gold_assert(!from->has_plt_offset()); gold_assert(!from->has_warning_); gold_assert(!from->is_copied_from_dynobj_); gold_assert(!from->is_forced_local_); } // Override a symbol with a special symbol. template void Sized_symbol::override_with_special(const Sized_symbol* from) { this->override_base_with_special(from); this->value_ = from->value_; this->symsize_ = from->symsize_; } // Override TOSYM with the special symbol FROMSYM. This handles all // aliases of TOSYM. template void Symbol_table::override_with_special(Sized_symbol* tosym, const Sized_symbol* fromsym) { tosym->override_with_special(fromsym); if (tosym->has_alias()) { Symbol* sym = this->weak_aliases_[tosym]; gold_assert(sym != NULL); Sized_symbol* ssym = this->get_sized_symbol(sym); do { ssym->override_with_special(fromsym); sym = this->weak_aliases_[ssym]; gold_assert(sym != NULL); ssym = this->get_sized_symbol(sym); } while (ssym != tosym); } if (tosym->binding() == elfcpp::STB_LOCAL || ((tosym->visibility() == elfcpp::STV_HIDDEN || tosym->visibility() == elfcpp::STV_INTERNAL) && (tosym->binding() == elfcpp::STB_GLOBAL || tosym->binding() == elfcpp::STB_GNU_UNIQUE || tosym->binding() == elfcpp::STB_WEAK) && !parameters->options().relocatable())) this->force_local(tosym); } // Instantiate the templates we need. We could use the configure // script to restrict this to only the ones needed for implemented // targets. // We have to instantiate both big and little endian versions because // these are used by other templates that depends on size only. #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) template void Symbol_table::resolve<32, false>( Sized_symbol<32>* to, const elfcpp::Sym<32, false>& sym, unsigned int st_shndx, bool is_ordinary, unsigned int orig_st_shndx, Object* object, const char* version); template void Symbol_table::resolve<32, true>( Sized_symbol<32>* to, const elfcpp::Sym<32, true>& sym, unsigned int st_shndx, bool is_ordinary, unsigned int orig_st_shndx, Object* object, const char* version); #endif #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) template void Symbol_table::resolve<64, false>( Sized_symbol<64>* to, const elfcpp::Sym<64, false>& sym, unsigned int st_shndx, bool is_ordinary, unsigned int orig_st_shndx, Object* object, const char* version); template void Symbol_table::resolve<64, true>( Sized_symbol<64>* to, const elfcpp::Sym<64, true>& sym, unsigned int st_shndx, bool is_ordinary, unsigned int orig_st_shndx, Object* object, const char* version); #endif #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) template void Symbol_table::override_with_special<32>(Sized_symbol<32>*, const Sized_symbol<32>*); #endif #if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) template void Symbol_table::override_with_special<64>(Sized_symbol<64>*, const Sized_symbol<64>*); #endif } // End namespace gold.