X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=gold%2Fresolve.cc;h=0da8da2218a13e977b2889dd0c5bbf80836e41ae;hb=d180bcbd34b9ed5f0062636786ff31c803c2f735;hp=82af9b4c6e83afc800cc6932185a3f573a8ea235;hpb=029ba973354c8eb02c476d3ba8c7f555344afdce;p=deliverable%2Fbinutils-gdb.git diff --git a/gold/resolve.cc b/gold/resolve.cc index 82af9b4c6e..0da8da2218 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 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc. // Written by Ian Lance Taylor . // This file is part of gold. @@ -178,6 +178,7 @@ symbol_to_bits(elfcpp::STB binding, bool is_dynamic, switch (binding) { case elfcpp::STB_GLOBAL: + case elfcpp::STB_GNU_UNIQUE: bits = global_flag; break; @@ -194,7 +195,7 @@ 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; } @@ -244,6 +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; @@ -280,7 +296,7 @@ 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 @@ -296,42 +312,18 @@ Symbol_table::resolve(Sized_symbol* to, } } - 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; - if (Symbol_table::should_override(to, frombits, object, - &adjust_common_sizes)) - { - typename Sized_symbol::Size_type tosize = to->symsize(); - - this->override(to, sym, st_shndx, is_ordinary, object, version); - - if (adjust_common_sizes && tosize > to->symsize()) - to->set_symsize(tosize); - } - else - { - if (adjust_common_sizes && sym.get_st_size() > to->symsize()) - to->set_symsize(sym.get_st_size()); - // The ELF ABI says that even for a reference to a symbol we - // merge the visibility. - to->override_visibility(sym.get_st_visibility()); - } - // 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; + // 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 + && (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 @@ -344,12 +336,79 @@ Symbol_table::resolve(Sized_symbol* to, && to->name()[0] == '_' && to->name()[1] == 'Z') { Symbol_location fromloc - = { object, orig_st_shndx, sym.get_st_value() }; + = { object, orig_st_shndx, static_cast(sym.get_st_value()) }; Symbol_location toloc = { to->object(), to->shndx(&to_is_ordinary), - to->value() }; + static_cast(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, sym.get_st_type(), 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) + { + 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) + { + 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()); + } + + 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 @@ -361,9 +420,12 @@ 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) @@ -383,7 +445,13 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits, to->type()); } - // FIXME: Warn if either but not both of TO and SYM are STT_TLS. + if (to->type() == elfcpp::STT_TLS + ? fromtype != elfcpp::STT_TLS + : fromtype == elfcpp::STT_TLS) + 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 @@ -419,17 +487,13 @@ 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; - // FIXME: Do a better job of reporting locations. - gold_error(_("%s: multiple definition of %s"), - object != NULL ? object->name().c_str() : _("command line"), - to->demangled_name().c_str()); - gold_error(_("%s: previous definition here"), - (to->source() == Symbol::FROM_OBJECT - ? to->object()->name().c_str() - : _("command line"))); + if (!parameters->options().muldefs()) + Symbol_table::report_resolve_problem(true, + _("multiple definition of '%s'"), + to, defined, object); return false; case WEAK_DEF * 16 + DEF: @@ -464,8 +528,12 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits, 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. FIXME: We should optionally issue, version a - // warning. + // 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: @@ -495,7 +563,12 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits, case DYN_COMMON * 16 + WEAK_DEF: case DYN_WEAK_COMMON * 16 + WEAK_DEF: // A weak definition does override a definition in a dynamic - // object. FIXME: We should optionally issue a warning. + // 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: @@ -506,12 +579,17 @@ 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: @@ -529,12 +607,22 @@ 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: @@ -545,12 +633,16 @@ 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: @@ -566,17 +658,28 @@ 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: @@ -611,6 +714,11 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits, 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: @@ -716,18 +824,80 @@ 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. 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) +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; } @@ -736,7 +906,8 @@ 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()); this->source_ = from->source_; switch (from->source_) @@ -758,7 +929,16 @@ 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_); @@ -772,11 +952,12 @@ 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_); @@ -820,6 +1001,7 @@ Symbol_table::override_with_special(Sized_symbol* tosym, || ((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); @@ -829,7 +1011,10 @@ 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>( @@ -840,9 +1025,7 @@ 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>( @@ -855,7 +1038,7 @@ 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>( @@ -866,9 +1049,7 @@ 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>(