X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=gold%2Fresolve.cc;h=63ed5e7207449c7a89c7aee459be0efaeab40c4d;hb=f960754aeea602f787d1828efb0f9a8baeca646e;hp=b890ed0952c1e1a949b60a19a72503250744008f;hpb=d20222a1e7d31611f3a805133ea6f37cd6174fa2;p=deliverable%2Fbinutils-gdb.git diff --git a/gold/resolve.cc b/gold/resolve.cc index b890ed0952..63ed5e7207 100644 --- a/gold/resolve.cc +++ b/gold/resolve.cc @@ -1,6 +1,6 @@ // resolve.cc -- symbol resolution for gold -// Copyright 2006, 2007 Free Software Foundation, Inc. +// Copyright 2006, 2007, 2008 Free Software Foundation, Inc. // Written by Ian Lance Taylor . // This file is part of gold. @@ -71,6 +71,35 @@ Sized_symbol::override(const elfcpp::Sym& sym, 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, + Object* object, const char* version) +{ + tosym->override(fromsym, object, version); + if (tosym->has_alias()) + { + Symbol* sym = this->weak_aliases_[tosym]; + gold_assert(sym != NULL); + Sized_symbol* ssym; + ssym = this->get_sized_symbol SELECT_SIZE_NAME(size) (sym + SELECT_SIZE(size)); + do + { + ssym->override(fromsym, object, version); + sym = this->weak_aliases_[ssym]; + gold_assert(sym != NULL); + ssym = this->get_sized_symbol SELECT_SIZE_NAME(size) ( + sym SELECT_SIZE(size)); + } + 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 @@ -90,14 +119,76 @@ 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, elfcpp::STT type) +{ + unsigned int bits; + + switch (binding) + { + case elfcpp::STB_GLOBAL: + 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")); + 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: + bits |= common_flag; + break; + + default: + if (type == elfcpp::STT_COMMON) + 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. SYM is the new -// symbol, seen in OBJECT. VERSION of the version of SYM. +// we see a symbol. TO is the pre-existing symbol. ORIG_SYM is the +// new symbol, seen in OBJECT. SYM is almost always identical to +// ORIG_SYM, but may be munged (for instance, if we determine the +// symbol is in a to-be-discarded section, we'll set sym's shndx to +// UNDEFINED). VERSION of the version of SYM. template void Symbol_table::resolve(Sized_symbol* to, const elfcpp::Sym& sym, + const elfcpp::Sym& orig_sym, Object* object, const char* version) { if (object->target()->has_resolve()) @@ -121,53 +212,10 @@ Symbol_table::resolve(Sized_symbol* to, to->set_in_dyn(); } - unsigned int frombits; - switch (sym.get_st_bind()) - { - case elfcpp::STB_GLOBAL: - frombits = global_flag; - break; - - case elfcpp::STB_WEAK: - frombits = weak_flag; - break; - - case elfcpp::STB_LOCAL: - gold_error(_("%s: invalid STB_LOCAL symbol %s in external symbols"), - object->name().c_str(), to->name()); - frombits = global_flag; - break; - - default: - gold_error(_("%s: unsupported symbol binding %d for symbol %s"), - object->name().c_str(), - static_cast(sym.get_st_bind()), to->name()); - frombits = global_flag; - break; - } - - if (!object->is_dynamic()) - frombits |= regular_flag; - else - frombits |= dynamic_flag; - - switch (sym.get_st_shndx()) - { - case elfcpp::SHN_UNDEF: - frombits |= undef_flag; - break; - - case elfcpp::SHN_COMMON: - frombits |= common_flag; - break; - - default: - if (sym.get_st_type() == elfcpp::STT_COMMON) - frombits |= common_flag; - else - frombits |= def_flag; - break; - } + unsigned int frombits = symbol_to_bits(sym.get_st_bind(), + object->is_dynamic(), + sym.get_st_shndx(), + sym.get_st_type()); bool adjust_common_sizes; if (Symbol_table::should_override(to, frombits, object, @@ -175,7 +223,7 @@ Symbol_table::resolve(Sized_symbol* to, { typename Sized_symbol::Size_type tosize = to->symsize(); - to->override(sym, object, version); + this->override(to, sym, object, version); if (adjust_common_sizes && tosize > to->symsize()) to->set_symsize(tosize); @@ -185,6 +233,35 @@ Symbol_table::resolve(Sized_symbol* to, if (adjust_common_sizes && sym.get_st_size() > to->symsize()) to->set_symsize(sym.get_st_size()); } + + // 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.) + // We use orig_sym here because we want the symbol exactly as it + // appears in the object file, not munged via our future processing. + if (parameters->detect_odr_violations() + && orig_sym.get_st_bind() == elfcpp::STB_WEAK + && to->binding() == elfcpp::STB_WEAK + && orig_sym.get_st_shndx() != elfcpp::SHN_UNDEF + && to->shndx() != elfcpp::SHN_UNDEF + && orig_sym.get_st_size() != 0 // Ignore weird 0-sized symbols. + && to->symsize() != 0 + && (orig_sym.get_st_type() != to->type() + || orig_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_sym.get_st_shndx(), orig_sym.get_st_value() }; + Symbol_location toloc = { to->object(), to->shndx(), to->value() }; + this->candidate_odr_violations_[to->name()].insert(fromloc); + this->candidate_odr_violations_[to->name()].insert(toloc); + } } // Handle the core of symbol resolution. This is called with the @@ -201,50 +278,14 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits, *adjust_common_sizes = false; unsigned int tobits; - switch (to->binding()) - { - case elfcpp::STB_GLOBAL: - tobits = global_flag; - break; - - case elfcpp::STB_WEAK: - tobits = weak_flag; - break; - - case elfcpp::STB_LOCAL: - // We should only see externally visible symbols in the symbol - // table. - gold_unreachable(); - - default: - // Any target which wants to handle STB_LOOS, etc., needs to - // define a resolve method. - gold_unreachable(); - } - - if (to->source() == Symbol::FROM_OBJECT - && to->object()->is_dynamic()) - tobits |= dynamic_flag; + if (to->source() == Symbol::FROM_OBJECT) + tobits = symbol_to_bits(to->binding(), + to->object()->is_dynamic(), + to->shndx(), + to->type()); else - tobits |= regular_flag; - - switch (to->shndx()) - { - case elfcpp::SHN_UNDEF: - tobits |= undef_flag; - break; - - case elfcpp::SHN_COMMON: - tobits |= common_flag; - break; - - default: - if (to->type() == elfcpp::STT_COMMON) - tobits |= common_flag; - else - tobits |= def_flag; - break; - } + tobits = symbol_to_bits(to->binding(), false, elfcpp::SHN_ABS, + to->type()); // FIXME: Warn if either but not both of TO and SYM are STT_TLS. @@ -280,7 +321,7 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits, // FIXME: Do a better job of reporting locations. gold_error(_("%s: multiple definition of %s"), object != NULL ? object->name().c_str() : _("command line"), - to->name()); + to->demangled_name().c_str()); gold_error(_("%s: previous definition here"), (to->source() == Symbol::FROM_OBJECT ? to->object()->name().c_str() @@ -591,6 +632,8 @@ 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()); + this->source_ = from->source_; switch (from->source_) { @@ -623,6 +666,21 @@ Symbol::override_base_with_special(const Symbol* from) // 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; + + // 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_got_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_); } // Override a symbol with a special symbol. @@ -636,6 +694,36 @@ Sized_symbol::override_with_special(const Sized_symbol* from) 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; + ssym = this->get_sized_symbol SELECT_SIZE_NAME(size) (sym + SELECT_SIZE(size)); + do + { + ssym->override_with_special(fromsym); + sym = this->weak_aliases_[ssym]; + gold_assert(sym != NULL); + ssym = this->get_sized_symbol SELECT_SIZE_NAME(size) ( + sym SELECT_SIZE(size)); + } + while (ssym != tosym); + } + if (tosym->binding() == elfcpp::STB_LOCAL) + 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. @@ -646,6 +734,7 @@ void Symbol_table::resolve<32, false>( Sized_symbol<32>* to, const elfcpp::Sym<32, false>& sym, + const elfcpp::Sym<32, false>& orig_sym, Object* object, const char* version); #endif @@ -656,6 +745,7 @@ void Symbol_table::resolve<32, true>( Sized_symbol<32>* to, const elfcpp::Sym<32, true>& sym, + const elfcpp::Sym<32, true>& orig_sym, Object* object, const char* version); #endif @@ -666,6 +756,7 @@ void Symbol_table::resolve<64, false>( Sized_symbol<64>* to, const elfcpp::Sym<64, false>& sym, + const elfcpp::Sym<64, false>& orig_sym, Object* object, const char* version); #endif @@ -676,6 +767,7 @@ void Symbol_table::resolve<64, true>( Sized_symbol<64>* to, const elfcpp::Sym<64, true>& sym, + const elfcpp::Sym<64, true>& orig_sym, Object* object, const char* version); #endif @@ -683,13 +775,15 @@ Symbol_table::resolve<64, true>( #if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG) template void -Sized_symbol<32>::override_with_special(const Sized_symbol<32>*); +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 -Sized_symbol<64>::override_with_special(const Sized_symbol<64>*); +Symbol_table::override_with_special<64>(Sized_symbol<64>*, + const Sized_symbol<64>*); #endif } // End namespace gold.