X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=gold%2Fresolve.cc;h=fdae0bae4a4bc2b9f676f91b67ab9ef1b79e406f;hb=b8cf50755b573140aae71f7247b604373fcdfbeb;hp=89b10b9f9a8a8c3edbdc0360d12b07106527ca6a;hpb=adcf2816e2fcdf7f871270d98f8cd2b83864d56c;p=external%2Fbinutils.git diff --git a/gold/resolve.cc b/gold/resolve.cc index 89b10b9..fdae0ba 100644 --- a/gold/resolve.cc +++ b/gold/resolve.cc @@ -1,6 +1,6 @@ // resolve.cc -- symbol resolution for gold -// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc. +// Copyright (C) 2006-2015 Free Software Foundation, Inc. // Written by Ian Lance Taylor . // This file is part of gold. @@ -96,7 +96,9 @@ Symbol::override_base(const elfcpp::Sym& sym, this->override_version(version); this->u_.from_object.shndx = st_shndx; this->is_ordinary_shndx_ = is_ordinary; - this->type_ = sym.get_st_type(); + // Don't override st_type from plugin placeholder symbols. + if (object->pluginobj() == NULL) + 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(); @@ -171,7 +173,7 @@ static const unsigned int common_flag = 2 << def_undef_or_common_shift; static unsigned int symbol_to_bits(elfcpp::STB binding, bool is_dynamic, - unsigned int shndx, bool is_ordinary, elfcpp::STT type) + unsigned int shndx, bool is_ordinary) { unsigned int bits; @@ -195,7 +197,7 @@ symbol_to_bits(elfcpp::STB binding, bool is_dynamic, default: // Any target which wants to handle STB_LOOS, etc., needs to // define a resolve method. - gold_error(_("unsupported symbol binding")); + gold_error(_("unsupported symbol binding %d"), static_cast(binding)); bits = global_flag; } @@ -216,9 +218,7 @@ symbol_to_bits(elfcpp::STB binding, bool is_dynamic, break; default: - if (type == elfcpp::STT_COMMON) - bits |= common_flag; - else if (!is_ordinary && Symbol::is_common_shndx(shndx)) + if (!is_ordinary && Symbol::is_common_shndx(shndx)) bits |= common_flag; else bits |= def_flag; @@ -245,6 +245,21 @@ Symbol_table::resolve(Sized_symbol* to, unsigned int orig_st_shndx, Object* object, const char* version) { + // It's possible for a symbol to be defined in an object file + // using .symver to give it a version, and for there to also be + // a linker script giving that symbol the same version. We + // don't want to give a multiple-definition error for this + // harmless redefinition. + bool to_is_ordinary; + if (to->source() == Symbol::FROM_OBJECT + && to->object() == object + && is_ordinary + && to->is_defined() + && to->shndx(&to_is_ordinary) == st_shndx + && to_is_ordinary + && to->value() == sym.get_st_value()) + return; + if (parameters->target().has_resolve()) { Sized_target* sized_target; @@ -255,6 +270,15 @@ Symbol_table::resolve(Sized_symbol* to, if (!object->is_dynamic()) { + if (sym.get_st_type() == elfcpp::STT_COMMON + && (is_ordinary || !Symbol::is_common_shndx(st_shndx))) + { + gold_warning(_("STT_COMMON symbol '%s' in %s " + "is not in a common section"), + to->demangled_name().c_str(), + to->object()->name().c_str()); + return; + } // Record that we've seen this symbol in a regular object. to->set_in_reg(); } @@ -281,40 +305,120 @@ Symbol_table::resolve(Sized_symbol* to, // 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) + if (object->pluginobj() == NULL && !object->is_dynamic()) to->set_in_real_elf(); // If we're processing replacement files, allow new symbols to override // the placeholders from the plugin objects. + // Treat common symbols specially since it is possible that an ELF + // file increased the size of the alignment. 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; + bool adjust_common = false; + typename Sized_symbol::Size_type tosize = 0; + typename Sized_symbol::Value_type tovalue = 0; + if (to->is_common() + && !is_ordinary && Symbol::is_common_shndx(st_shndx)) + { + adjust_common = true; + tosize = to->symsize(); + tovalue = to->value(); + } + this->override(to, sym, st_shndx, is_ordinary, object, version); + if (adjust_common) + { + if (tosize > to->symsize()) + to->set_symsize(tosize); + if (tovalue > to->value()) + to->set_value(tovalue); + } + 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.) + 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, static_cast(sym.get_st_value()) }; + Symbol_location toloc = { to->object(), to->shndx(&to_is_ordinary), + static_cast(to->value()) }; + this->candidate_odr_violations_[to->name()].insert(fromloc); + this->candidate_odr_violations_[to->name()].insert(toloc); + } + + // Plugins don't provide a symbol type, so adopt the existing type + // if the FROM symbol is from a plugin. + elfcpp::STT fromtype = (object->pluginobj() != NULL + ? to->type() + : sym.get_st_type()); unsigned int frombits = symbol_to_bits(sym.get_st_bind(), object->is_dynamic(), - st_shndx, is_ordinary, - sym.get_st_type()); + st_shndx, is_ordinary); bool adjust_common_sizes; + bool adjust_dyndef; typename Sized_symbol::Size_type tosize = to->symsize(); - if (Symbol_table::should_override(to, frombits, object, - &adjust_common_sizes)) + if (Symbol_table::should_override(to, frombits, fromtype, OBJECT, + object, &adjust_common_sizes, + &adjust_dyndef)) { + elfcpp::STB tobinding = to->binding(); + typename Sized_symbol::Value_type tovalue = to->value(); this->override(to, sym, st_shndx, is_ordinary, object, version); - if (adjust_common_sizes && tosize > to->symsize()) - to->set_symsize(tosize); + if (adjust_common_sizes) + { + if (tosize > to->symsize()) + to->set_symsize(tosize); + if (tovalue > to->value()) + to->set_value(tovalue); + } + 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_common_sizes) + { + if (sym.get_st_size() > tosize) + to->set_symsize(sym.get_st_size()); + if (sym.get_st_value() > to->value()) + to->set_value(sym.get_st_value()); + } + 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()); @@ -326,46 +430,16 @@ Symbol_table::resolve(Sized_symbol* to, Symbol_table::report_resolve_problem(false, _("common of '%s' overriding " "smaller common"), - to, object); + 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); + to, OBJECT, object); else Symbol_table::report_resolve_problem(false, _("multiple common of '%s'"), - to, object); - } - - // 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. (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); + to, OBJECT, object); } } @@ -378,17 +452,18 @@ Symbol_table::resolve(Sized_symbol* to, bool Symbol_table::should_override(const Symbol* to, unsigned int frombits, - Object* object, bool* adjust_common_sizes) + elfcpp::STT fromtype, 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()); + tobits = symbol_to_bits(to->binding(), false, elfcpp::SHN_UNDEF, true); else if (to->source() != Symbol::FROM_OBJECT) - tobits = symbol_to_bits(to->binding(), false, elfcpp::SHN_ABS, false, - to->type()); + tobits = symbol_to_bits(to->binding(), false, elfcpp::SHN_ABS, false); else { bool is_ordinary; @@ -396,11 +471,15 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits, tobits = symbol_to_bits(to->binding(), to->object()->is_dynamic(), shndx, - is_ordinary, - to->type()); + is_ordinary); } - // FIXME: Warn if either but not both of TO and SYM are STT_TLS. + if ((to->type() == elfcpp::STT_TLS) ^ (fromtype == elfcpp::STT_TLS) + && !to->is_placeholder()) + Symbol_table::report_resolve_problem(true, + _("symbol '%s' used as both __thread " + "and non-__thread"), + to, defined, object); // We use a giant switch table for symbol resolution. This code is // unwieldy, but: 1) it is efficient; 2) we definitely handle all @@ -436,12 +515,13 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits, // --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->just_symbols()) + || (object != NULL && object->just_symbols())) return false; - Symbol_table::report_resolve_problem(true, - _("multiple definition of '%s'"), - to, object); + if (!parameters->options().muldefs()) + Symbol_table::report_resolve_problem(true, + _("multiple definition of '%s'"), + to, defined, object); return false; case WEAK_DEF * 16 + DEF: @@ -481,7 +561,7 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits, Symbol_table::report_resolve_problem(false, _("definition of '%s' overriding " "common"), - to, object); + to, defined, object); return true; case DEF * 16 + WEAK_DEF: @@ -516,7 +596,7 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits, Symbol_table::report_resolve_problem(false, _("definition of '%s' overriding " "dynamic common definition"), - to, object); + to, defined, object); return true; case DEF * 16 + DYN_DEF: @@ -527,12 +607,17 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits, return false; case UNDEF * 16 + DYN_DEF: - case WEAK_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: @@ -550,12 +635,22 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits, return false; case UNDEF * 16 + DYN_WEAK_DEF: - case WEAK_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: @@ -566,12 +661,16 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits, case DEF * 16 + UNDEF: case WEAK_DEF * 16 + UNDEF: - case DYN_DEF * 16 + UNDEF: - case DYN_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: @@ -587,17 +686,28 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits, case DEF * 16 + WEAK_UNDEF: case WEAK_DEF * 16 + WEAK_UNDEF: - case DYN_DEF * 16 + WEAK_UNDEF: - case DYN_WEAK_DEF * 16 + WEAK_UNDEF: case UNDEF * 16 + WEAK_UNDEF: case WEAK_UNDEF * 16 + WEAK_UNDEF: case DYN_UNDEF * 16 + WEAK_UNDEF: - case DYN_WEAK_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. + // 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: @@ -636,7 +746,7 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits, Symbol_table::report_resolve_problem(false, _("common '%s' overridden by " "previous definition"), - to, object); + to, defined, object); return false; case WEAK_DEF * 16 + COMMON: @@ -745,7 +855,8 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits, // 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. OBJECT is where the new symbol was found. +// 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 @@ -753,7 +864,8 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits, void Symbol_table::report_resolve_problem(bool is_error, const char* msg, - const Symbol* to, Object* object) + const Symbol* to, Defined defined, + Object* object) { std::string demangled(to->demangled_name()); size_t len = strlen(msg) + demangled.length() + 10; @@ -761,10 +873,28 @@ Symbol_table::report_resolve_problem(bool is_error, const char* msg, snprintf(buf, len, msg, demangled.c_str()); const char* objname; - if (object != NULL) - objname = object->name().c_str(); - else - objname = _("command line"); + 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); @@ -785,13 +915,17 @@ Symbol_table::report_resolve_problem(bool is_error, const char* msg, // defining special symbols. bool -Symbol_table::should_override_with_special(const Symbol* to) +Symbol_table::should_override_with_special(const Symbol* to, + elfcpp::STT fromtype, + 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, NULL, - &adjust_common_sizes); - gold_assert(!adjust_common_sizes); + bool ret = Symbol_table::should_override(to, frombits, fromtype, defined, + NULL, &adjust_common_sizes, + &adjust_dyn_def); + gold_assert(!adjust_common_sizes && !adjust_dyn_def); return ret; } @@ -800,7 +934,12 @@ Symbol_table::should_override_with_special(const Symbol* to) void Symbol::override_base_with_special(const Symbol* from) { - gold_assert(this->name_ == from->name_ || this->has_alias()); + bool same_name = this->name_ == from->name_; + gold_assert(same_name || this->has_alias()); + + // If we are overriding an undef, remember the original binding. + if (this->is_undefined()) + this->set_undef_binding(this->binding_); this->source_ = from->source_; switch (from->source_) @@ -822,7 +961,16 @@ Symbol::override_base_with_special(const Symbol* from) break; } - this->override_version(from->version_); + if (same_name) + { + // When overriding a versioned symbol with a special symbol, we + // may be changing the version. This will happen if we see a + // special symbol such as "_end" defined in a shared object with + // one version (from a version script), but we want to define it + // here with a different version (from a different version + // script). + this->version_ = from->version_; + } this->type_ = from->type_; this->binding_ = from->binding_; this->override_visibility(from->visibility_); @@ -836,11 +984,12 @@ Symbol::override_base_with_special(const Symbol* from) 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_target_special_ || this->is_target_special_); gold_assert(!from->is_forwarder_); - gold_assert(!from->has_plt_offset_); + gold_assert(!from->has_plt_offset()); gold_assert(!from->has_warning_); gold_assert(!from->is_copied_from_dynobj_); gold_assert(!from->is_forced_local_); @@ -894,7 +1043,10 @@ Symbol_table::override_with_special(Sized_symbol* tosym, // script to restrict this to only the ones needed for implemented // targets. -#ifdef HAVE_TARGET_32_LITTLE +// 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>( @@ -905,9 +1057,7 @@ Symbol_table::resolve<32, false>( unsigned int orig_st_shndx, Object* object, const char* version); -#endif -#ifdef HAVE_TARGET_32_BIG template void Symbol_table::resolve<32, true>( @@ -920,7 +1070,7 @@ Symbol_table::resolve<32, true>( const char* version); #endif -#ifdef HAVE_TARGET_64_LITTLE +#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG) template void Symbol_table::resolve<64, false>( @@ -931,9 +1081,7 @@ Symbol_table::resolve<64, false>( unsigned int orig_st_shndx, Object* object, const char* version); -#endif -#ifdef HAVE_TARGET_64_BIG template void Symbol_table::resolve<64, true>(