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author | Andrew Hsieh <andrewhsieh@google.com> | 2014-06-13 12:38:00 -0700 |
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committer | Andrew Hsieh <andrewhsieh@google.com> | 2014-06-13 12:38:00 -0700 |
commit | 54f1b3cf509cd889905287cb8ce6c5ae33911a21 (patch) | |
tree | e39b1a7fa04db86a8215b7f9d4656d74e394aec0 /binutils-2.25/gold/resolve.cc | |
parent | 2a6558a8ecfb81d75215b4ec7dc61113e12cfd5f (diff) | |
download | toolchain_binutils-54f1b3cf509cd889905287cb8ce6c5ae33911a21.zip toolchain_binutils-54f1b3cf509cd889905287cb8ce6c5ae33911a21.tar.gz toolchain_binutils-54f1b3cf509cd889905287cb8ce6c5ae33911a21.tar.bz2 |
Add upstream binutils-2.25 snapshot 4/4 2014
For MIPS -mmsa support
Change-Id: I08c4f002fa7b33dec85ed75956e6ab551bb03c96
Diffstat (limited to 'binutils-2.25/gold/resolve.cc')
-rw-r--r-- | binutils-2.25/gold/resolve.cc | 1085 |
1 files changed, 1085 insertions, 0 deletions
diff --git a/binutils-2.25/gold/resolve.cc b/binutils-2.25/gold/resolve.cc new file mode 100644 index 0000000..3b6e706 --- /dev/null +++ b/binutils-2.25/gold/resolve.cc @@ -0,0 +1,1085 @@ +// resolve.cc -- symbol resolution for gold + +// Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc. +// Written by Ian Lance Taylor <iant@google.com>. + +// 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<int size, bool big_endian> +void +Symbol::override_base(const elfcpp::Sym<size, big_endian>& 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; + // 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(); + if (object->is_dynamic()) + this->in_dyn_ = true; + else + this->in_reg_ = true; +} + +// Override the fields in Sized_symbol. + +template<int size> +template<bool big_endian> +void +Sized_symbol<size>::override(const elfcpp::Sym<size, big_endian>& 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<int size, bool big_endian> +void +Symbol_table::override(Sized_symbol<size>* tosym, + const elfcpp::Sym<size, big_endian>& 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<size>* ssym = this->get_sized_symbol<size>(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<size>(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<int>(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<int size, bool big_endian> +void +Symbol_table::resolve(Sized_symbol<size>* to, + const elfcpp::Sym<size, big_endian>& sym, + unsigned int st_shndx, bool is_ordinary, + 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<size, big_endian>* sized_target; + sized_target = parameters->sized_target<size, big_endian>(); + 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 && !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. + 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.) + 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<off_t>(sym.get_st_value()) }; + Symbol_location toloc = { to->object(), to->shndx(&to_is_ordinary), + static_cast<off_t>(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, + fromtype); + + bool adjust_common_sizes; + bool adjust_dyndef; + typename Sized_symbol<size>::Size_type tosize = to->symsize(); + if (Symbol_table::should_override(to, frombits, fromtype, OBJECT, + object, &adjust_common_sizes, + &adjust_dyndef)) + { + elfcpp::STB tobinding = to->binding(); + typename Sized_symbol<size>::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 +// 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, + 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()); + 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()); + } + + 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 + // 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, + 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, fromtype, 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) +{ + bool same_name = this->name_ == from->name_; + gold_assert(same_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; + } + + 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_); + 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<int size> +void +Sized_symbol<size>::override_with_special(const Sized_symbol<size>* 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<int size> +void +Symbol_table::override_with_special(Sized_symbol<size>* tosym, + const Sized_symbol<size>* fromsym) +{ + tosym->override_with_special(fromsym); + if (tosym->has_alias()) + { + Symbol* sym = this->weak_aliases_[tosym]; + gold_assert(sym != NULL); + Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym); + do + { + ssym->override_with_special(fromsym); + sym = this->weak_aliases_[ssym]; + gold_assert(sym != NULL); + ssym = this->get_sized_symbol<size>(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. |