1086 lines
35 KiB
C++
1086 lines
35 KiB
C++
// resolve.cc -- symbol resolution for gold
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// Copyright (C) 2006-2014 Free Software Foundation, Inc.
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// Written by Ian Lance Taylor <iant@google.com>.
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// This file is part of gold.
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 3 of the License, or
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// (at your option) any later version.
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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// MA 02110-1301, USA.
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#include "gold.h"
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#include "elfcpp.h"
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#include "target.h"
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#include "object.h"
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#include "symtab.h"
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#include "plugin.h"
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namespace gold
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{
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// Symbol methods used in this file.
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// This symbol is being overridden by another symbol whose version is
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// VERSION. Update the VERSION_ field accordingly.
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inline void
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Symbol::override_version(const char* version)
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{
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if (version == NULL)
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{
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// This is the case where this symbol is NAME/VERSION, and the
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// version was not marked as hidden. That makes it the default
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// version, so we create NAME/NULL. Later we see another symbol
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// NAME/NULL, and that symbol is overriding this one. In this
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// case, since NAME/VERSION is the default, we make NAME/NULL
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// override NAME/VERSION as well. They are already the same
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// Symbol structure. Setting the VERSION_ field to NULL ensures
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// that it will be output with the correct, empty, version.
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this->version_ = version;
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}
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else
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{
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// This is the case where this symbol is NAME/VERSION_ONE, and
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// now we see NAME/VERSION_TWO, and NAME/VERSION_TWO is
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// overriding NAME. If VERSION_ONE and VERSION_TWO are
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// different, then this can only happen when VERSION_ONE is NULL
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// and VERSION_TWO is not hidden.
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gold_assert(this->version_ == version || this->version_ == NULL);
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this->version_ = version;
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}
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}
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// This symbol is being overidden by another symbol whose visibility
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// is VISIBILITY. Updated the VISIBILITY_ field accordingly.
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inline void
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Symbol::override_visibility(elfcpp::STV visibility)
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{
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// The rule for combining visibility is that we always choose the
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// most constrained visibility. In order of increasing constraint,
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// visibility goes PROTECTED, HIDDEN, INTERNAL. This is the reverse
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// of the numeric values, so the effect is that we always want the
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// smallest non-zero value.
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if (visibility != elfcpp::STV_DEFAULT)
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{
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if (this->visibility_ == elfcpp::STV_DEFAULT)
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this->visibility_ = visibility;
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else if (this->visibility_ > visibility)
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this->visibility_ = visibility;
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}
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}
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// Override the fields in Symbol.
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template<int size, bool big_endian>
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void
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Symbol::override_base(const elfcpp::Sym<size, big_endian>& sym,
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unsigned int st_shndx, bool is_ordinary,
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Object* object, const char* version)
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{
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gold_assert(this->source_ == FROM_OBJECT);
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this->u_.from_object.object = object;
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this->override_version(version);
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this->u_.from_object.shndx = st_shndx;
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this->is_ordinary_shndx_ = is_ordinary;
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// Don't override st_type from plugin placeholder symbols.
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if (object->pluginobj() == NULL)
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this->type_ = sym.get_st_type();
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this->binding_ = sym.get_st_bind();
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this->override_visibility(sym.get_st_visibility());
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this->nonvis_ = sym.get_st_nonvis();
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if (object->is_dynamic())
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this->in_dyn_ = true;
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else
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this->in_reg_ = true;
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}
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// Override the fields in Sized_symbol.
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template<int size>
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template<bool big_endian>
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void
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Sized_symbol<size>::override(const elfcpp::Sym<size, big_endian>& sym,
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unsigned st_shndx, bool is_ordinary,
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Object* object, const char* version)
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{
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this->override_base(sym, st_shndx, is_ordinary, object, version);
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this->value_ = sym.get_st_value();
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this->symsize_ = sym.get_st_size();
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}
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// Override TOSYM with symbol FROMSYM, defined in OBJECT, with version
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// VERSION. This handles all aliases of TOSYM.
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template<int size, bool big_endian>
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void
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Symbol_table::override(Sized_symbol<size>* tosym,
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const elfcpp::Sym<size, big_endian>& fromsym,
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unsigned int st_shndx, bool is_ordinary,
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Object* object, const char* version)
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{
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tosym->override(fromsym, st_shndx, is_ordinary, object, version);
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if (tosym->has_alias())
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{
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Symbol* sym = this->weak_aliases_[tosym];
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gold_assert(sym != NULL);
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Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym);
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do
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{
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ssym->override(fromsym, st_shndx, is_ordinary, object, version);
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sym = this->weak_aliases_[ssym];
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gold_assert(sym != NULL);
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ssym = this->get_sized_symbol<size>(sym);
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}
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while (ssym != tosym);
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}
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}
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// The resolve functions build a little code for each symbol.
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// Bit 0: 0 for global, 1 for weak.
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// Bit 1: 0 for regular object, 1 for shared object
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// Bits 2-3: 0 for normal, 1 for undefined, 2 for common
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// This gives us values from 0 to 11.
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static const int global_or_weak_shift = 0;
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static const unsigned int global_flag = 0 << global_or_weak_shift;
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static const unsigned int weak_flag = 1 << global_or_weak_shift;
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static const int regular_or_dynamic_shift = 1;
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static const unsigned int regular_flag = 0 << regular_or_dynamic_shift;
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static const unsigned int dynamic_flag = 1 << regular_or_dynamic_shift;
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static const int def_undef_or_common_shift = 2;
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static const unsigned int def_flag = 0 << def_undef_or_common_shift;
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static const unsigned int undef_flag = 1 << def_undef_or_common_shift;
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static const unsigned int common_flag = 2 << def_undef_or_common_shift;
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// This convenience function combines all the flags based on facts
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// about the symbol.
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static unsigned int
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symbol_to_bits(elfcpp::STB binding, bool is_dynamic,
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unsigned int shndx, bool is_ordinary, elfcpp::STT type)
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{
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unsigned int bits;
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switch (binding)
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{
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case elfcpp::STB_GLOBAL:
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case elfcpp::STB_GNU_UNIQUE:
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bits = global_flag;
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break;
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case elfcpp::STB_WEAK:
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bits = weak_flag;
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break;
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case elfcpp::STB_LOCAL:
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// We should only see externally visible symbols in the symbol
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// table.
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gold_error(_("invalid STB_LOCAL symbol in external symbols"));
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bits = global_flag;
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default:
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// Any target which wants to handle STB_LOOS, etc., needs to
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// define a resolve method.
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gold_error(_("unsupported symbol binding %d"), static_cast<int>(binding));
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bits = global_flag;
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}
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if (is_dynamic)
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bits |= dynamic_flag;
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else
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bits |= regular_flag;
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switch (shndx)
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{
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case elfcpp::SHN_UNDEF:
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bits |= undef_flag;
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break;
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case elfcpp::SHN_COMMON:
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if (!is_ordinary)
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bits |= common_flag;
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break;
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default:
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if (type == elfcpp::STT_COMMON)
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bits |= common_flag;
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else if (!is_ordinary && Symbol::is_common_shndx(shndx))
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bits |= common_flag;
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else
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bits |= def_flag;
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break;
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}
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return bits;
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}
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// Resolve a symbol. This is called the second and subsequent times
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// we see a symbol. TO is the pre-existing symbol. ST_SHNDX is the
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// section index for SYM, possibly adjusted for many sections.
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// IS_ORDINARY is whether ST_SHNDX is a normal section index rather
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// than a special code. ORIG_ST_SHNDX is the original section index,
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// before any munging because of discarded sections, except that all
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// non-ordinary section indexes are mapped to SHN_UNDEF. VERSION is
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// the version of SYM.
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template<int size, bool big_endian>
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void
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Symbol_table::resolve(Sized_symbol<size>* to,
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const elfcpp::Sym<size, big_endian>& sym,
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unsigned int st_shndx, bool is_ordinary,
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unsigned int orig_st_shndx,
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Object* object, const char* version)
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{
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// It's possible for a symbol to be defined in an object file
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// using .symver to give it a version, and for there to also be
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// a linker script giving that symbol the same version. We
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// don't want to give a multiple-definition error for this
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// harmless redefinition.
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bool to_is_ordinary;
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if (to->source() == Symbol::FROM_OBJECT
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&& to->object() == object
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&& is_ordinary
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&& to->is_defined()
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&& to->shndx(&to_is_ordinary) == st_shndx
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&& to_is_ordinary
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&& to->value() == sym.get_st_value())
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return;
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if (parameters->target().has_resolve())
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{
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Sized_target<size, big_endian>* sized_target;
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sized_target = parameters->sized_target<size, big_endian>();
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sized_target->resolve(to, sym, object, version);
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return;
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}
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if (!object->is_dynamic())
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{
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// Record that we've seen this symbol in a regular object.
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to->set_in_reg();
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}
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else if (st_shndx == elfcpp::SHN_UNDEF
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&& (to->visibility() == elfcpp::STV_HIDDEN
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|| to->visibility() == elfcpp::STV_INTERNAL))
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{
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// A dynamic object cannot reference a hidden or internal symbol
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// defined in another object.
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gold_warning(_("%s symbol '%s' in %s is referenced by DSO %s"),
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(to->visibility() == elfcpp::STV_HIDDEN
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? "hidden"
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: "internal"),
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to->demangled_name().c_str(),
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to->object()->name().c_str(),
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object->name().c_str());
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return;
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}
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else
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{
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// Record that we've seen this symbol in a dynamic object.
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to->set_in_dyn();
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}
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// Record if we've seen this symbol in a real ELF object (i.e., the
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// symbol is referenced from outside the world known to the plugin).
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if (object->pluginobj() == NULL && !object->is_dynamic())
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to->set_in_real_elf();
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// If we're processing replacement files, allow new symbols to override
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// the placeholders from the plugin objects.
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if (to->source() == Symbol::FROM_OBJECT)
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{
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Pluginobj* obj = to->object()->pluginobj();
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if (obj != NULL
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&& parameters->options().plugins()->in_replacement_phase())
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{
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this->override(to, sym, st_shndx, is_ordinary, object, version);
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return;
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}
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}
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// A new weak undefined reference, merging with an old weak
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// reference, could be a One Definition Rule (ODR) violation --
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// especially if the types or sizes of the references differ. We'll
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// store such pairs and look them up later to make sure they
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// actually refer to the same lines of code. We also check
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// combinations of weak and strong, which might occur if one case is
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// inline and the other is not. (Note: not all ODR violations can
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// be found this way, and not everything this finds is an ODR
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// violation. But it's helpful to warn about.)
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if (parameters->options().detect_odr_violations()
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&& (sym.get_st_bind() == elfcpp::STB_WEAK
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|| to->binding() == elfcpp::STB_WEAK)
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&& orig_st_shndx != elfcpp::SHN_UNDEF
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&& to->shndx(&to_is_ordinary) != elfcpp::SHN_UNDEF
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&& to_is_ordinary
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&& sym.get_st_size() != 0 // Ignore weird 0-sized symbols.
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&& to->symsize() != 0
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&& (sym.get_st_type() != to->type()
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|| sym.get_st_size() != to->symsize())
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// C does not have a concept of ODR, so we only need to do this
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// on C++ symbols. These have (mangled) names starting with _Z.
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&& to->name()[0] == '_' && to->name()[1] == 'Z')
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{
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Symbol_location fromloc
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= { object, orig_st_shndx, static_cast<off_t>(sym.get_st_value()) };
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Symbol_location toloc = { to->object(), to->shndx(&to_is_ordinary),
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static_cast<off_t>(to->value()) };
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this->candidate_odr_violations_[to->name()].insert(fromloc);
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this->candidate_odr_violations_[to->name()].insert(toloc);
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}
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// Plugins don't provide a symbol type, so adopt the existing type
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// if the FROM symbol is from a plugin.
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elfcpp::STT fromtype = (object->pluginobj() != NULL
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? to->type()
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: sym.get_st_type());
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unsigned int frombits = symbol_to_bits(sym.get_st_bind(),
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object->is_dynamic(),
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st_shndx, is_ordinary,
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fromtype);
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bool adjust_common_sizes;
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bool adjust_dyndef;
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typename Sized_symbol<size>::Size_type tosize = to->symsize();
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if (Symbol_table::should_override(to, frombits, fromtype, OBJECT,
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object, &adjust_common_sizes,
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&adjust_dyndef))
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{
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elfcpp::STB tobinding = to->binding();
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typename Sized_symbol<size>::Value_type tovalue = to->value();
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this->override(to, sym, st_shndx, is_ordinary, object, version);
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if (adjust_common_sizes)
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{
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if (tosize > to->symsize())
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to->set_symsize(tosize);
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if (tovalue > to->value())
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to->set_value(tovalue);
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}
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if (adjust_dyndef)
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{
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// We are overriding an UNDEF or WEAK UNDEF with a DYN DEF.
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// Remember which kind of UNDEF it was for future reference.
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to->set_undef_binding(tobinding);
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}
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}
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else
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{
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if (adjust_common_sizes)
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{
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if (sym.get_st_size() > tosize)
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to->set_symsize(sym.get_st_size());
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if (sym.get_st_value() > to->value())
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to->set_value(sym.get_st_value());
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}
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if (adjust_dyndef)
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{
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// We are keeping a DYN DEF after seeing an UNDEF or WEAK UNDEF.
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// Remember which kind of UNDEF it was.
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to->set_undef_binding(sym.get_st_bind());
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}
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// The ELF ABI says that even for a reference to a symbol we
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// merge the visibility.
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to->override_visibility(sym.get_st_visibility());
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}
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if (adjust_common_sizes && parameters->options().warn_common())
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{
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if (tosize > sym.get_st_size())
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Symbol_table::report_resolve_problem(false,
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_("common of '%s' overriding "
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"smaller common"),
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to, OBJECT, object);
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else if (tosize < sym.get_st_size())
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Symbol_table::report_resolve_problem(false,
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_("common of '%s' overidden by "
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"larger common"),
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to, OBJECT, object);
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else
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Symbol_table::report_resolve_problem(false,
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_("multiple common of '%s'"),
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to, OBJECT, object);
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}
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}
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// Handle the core of symbol resolution. This is called with the
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// existing symbol, TO, and a bitflag describing the new symbol. This
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// returns true if we should override the existing symbol with the new
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// one, and returns false otherwise. It sets *ADJUST_COMMON_SIZES to
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// true if we should set the symbol size to the maximum of the TO and
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// FROM sizes. It handles error conditions.
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bool
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Symbol_table::should_override(const Symbol* to, unsigned int frombits,
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elfcpp::STT fromtype, Defined defined,
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Object* object, bool* adjust_common_sizes,
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bool* adjust_dyndef)
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{
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*adjust_common_sizes = false;
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*adjust_dyndef = false;
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unsigned int tobits;
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if (to->source() == Symbol::IS_UNDEFINED)
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tobits = symbol_to_bits(to->binding(), false, elfcpp::SHN_UNDEF, true,
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to->type());
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else if (to->source() != Symbol::FROM_OBJECT)
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tobits = symbol_to_bits(to->binding(), false, elfcpp::SHN_ABS, false,
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to->type());
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else
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{
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bool is_ordinary;
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unsigned int shndx = to->shndx(&is_ordinary);
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tobits = symbol_to_bits(to->binding(),
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to->object()->is_dynamic(),
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shndx,
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is_ordinary,
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to->type());
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}
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if ((to->type() == elfcpp::STT_TLS) ^ (fromtype == elfcpp::STT_TLS)
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&& !to->is_placeholder())
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Symbol_table::report_resolve_problem(true,
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_("symbol '%s' used as both __thread "
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"and non-__thread"),
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to, defined, object);
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// We use a giant switch table for symbol resolution. This code is
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// unwieldy, but: 1) it is efficient; 2) we definitely handle all
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// cases; 3) it is easy to change the handling of a particular case.
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// The alternative would be a series of conditionals, but it is easy
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// to get the ordering wrong. This could also be done as a table,
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// but that is no easier to understand than this large switch
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// statement.
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// These are the values generated by the bit codes.
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enum
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{
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DEF = global_flag | regular_flag | def_flag,
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WEAK_DEF = weak_flag | regular_flag | def_flag,
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DYN_DEF = global_flag | dynamic_flag | def_flag,
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DYN_WEAK_DEF = weak_flag | dynamic_flag | def_flag,
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UNDEF = global_flag | regular_flag | undef_flag,
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WEAK_UNDEF = weak_flag | regular_flag | undef_flag,
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DYN_UNDEF = global_flag | dynamic_flag | undef_flag,
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DYN_WEAK_UNDEF = weak_flag | dynamic_flag | undef_flag,
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COMMON = global_flag | regular_flag | common_flag,
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WEAK_COMMON = weak_flag | regular_flag | common_flag,
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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.
|