1ae4d23b73
* options.h (class General_options): Add --warn-common. * resolve.cc (Symbol_table::resolve): Handle --warn-common when merging two common symbols. (Symbol_table::should_override): Handle --warn-common when merging a common symbol with a defined symbol. Use report_resolve_problem for multiple definitions. (Symbol_table::report_resolve_problem): New function. * symtab.h (class Symbol_table): Declare report_resolve_problem.
1746 lines
55 KiB
C++
1746 lines
55 KiB
C++
// symtab.h -- the gold symbol table -*- C++ -*-
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// Copyright 2006, 2007, 2008, 2009 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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// Symbol_table
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// The symbol table.
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#ifndef GOLD_SYMTAB_H
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#define GOLD_SYMTAB_H
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#include <string>
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#include <utility>
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#include <vector>
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#include "elfcpp.h"
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#include "parameters.h"
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#include "stringpool.h"
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#include "object.h"
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namespace gold
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{
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class Mapfile;
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class Object;
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class Relobj;
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template<int size, bool big_endian>
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class Sized_relobj;
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template<int size, bool big_endian>
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class Sized_pluginobj;
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class Dynobj;
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template<int size, bool big_endian>
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class Sized_dynobj;
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class Versions;
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class Version_script_info;
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class Input_objects;
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class Output_data;
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class Output_section;
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class Output_segment;
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class Output_file;
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class Output_symtab_xindex;
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class Garbage_collection;
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class Icf;
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// The base class of an entry in the symbol table. The symbol table
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// can have a lot of entries, so we don't want this class to big.
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// Size dependent fields can be found in the template class
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// Sized_symbol. Targets may support their own derived classes.
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class Symbol
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{
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public:
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// Because we want the class to be small, we don't use any virtual
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// functions. But because symbols can be defined in different
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// places, we need to classify them. This enum is the different
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// sources of symbols we support.
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enum Source
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{
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// Symbol defined in a relocatable or dynamic input file--this is
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// the most common case.
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FROM_OBJECT,
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// Symbol defined in an Output_data, a special section created by
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// the target.
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IN_OUTPUT_DATA,
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// Symbol defined in an Output_segment, with no associated
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// section.
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IN_OUTPUT_SEGMENT,
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// Symbol value is constant.
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IS_CONSTANT,
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// Symbol is undefined.
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IS_UNDEFINED
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};
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// When the source is IN_OUTPUT_SEGMENT, we need to describe what
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// the offset means.
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enum Segment_offset_base
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{
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// From the start of the segment.
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SEGMENT_START,
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// From the end of the segment.
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SEGMENT_END,
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// From the filesz of the segment--i.e., after the loaded bytes
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// but before the bytes which are allocated but zeroed.
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SEGMENT_BSS
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};
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// Return the symbol name.
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const char*
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name() const
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{ return this->name_; }
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// Return the (ANSI) demangled version of the name, if
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// parameters.demangle() is true. Otherwise, return the name. This
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// is intended to be used only for logging errors, so it's not
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// super-efficient.
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std::string
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demangled_name() const;
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// Return the symbol version. This will return NULL for an
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// unversioned symbol.
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const char*
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version() const
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{ return this->version_; }
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// Return whether this version is the default for this symbol name
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// (eg, "foo@@V2" is a default version; "foo@V1" is not). Only
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// meaningful for versioned symbols.
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bool
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is_default() const
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{
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gold_assert(this->version_ != NULL);
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return this->is_def_;
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}
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// Set that this version is the default for this symbol name.
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void
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set_is_default()
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{ this->is_def_ = true; }
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// Return the symbol source.
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Source
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source() const
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{ return this->source_; }
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// Return the object with which this symbol is associated.
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Object*
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object() const
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{
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gold_assert(this->source_ == FROM_OBJECT);
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return this->u_.from_object.object;
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}
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// Return the index of the section in the input relocatable or
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// dynamic object file.
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unsigned int
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shndx(bool* is_ordinary) const
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{
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gold_assert(this->source_ == FROM_OBJECT);
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*is_ordinary = this->is_ordinary_shndx_;
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return this->u_.from_object.shndx;
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}
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// Return the output data section with which this symbol is
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// associated, if the symbol was specially defined with respect to
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// an output data section.
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Output_data*
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output_data() const
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{
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gold_assert(this->source_ == IN_OUTPUT_DATA);
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return this->u_.in_output_data.output_data;
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}
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// If this symbol was defined with respect to an output data
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// section, return whether the value is an offset from end.
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bool
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offset_is_from_end() const
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{
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gold_assert(this->source_ == IN_OUTPUT_DATA);
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return this->u_.in_output_data.offset_is_from_end;
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}
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// Return the output segment with which this symbol is associated,
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// if the symbol was specially defined with respect to an output
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// segment.
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Output_segment*
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output_segment() const
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{
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gold_assert(this->source_ == IN_OUTPUT_SEGMENT);
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return this->u_.in_output_segment.output_segment;
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}
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// If this symbol was defined with respect to an output segment,
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// return the offset base.
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Segment_offset_base
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offset_base() const
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{
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gold_assert(this->source_ == IN_OUTPUT_SEGMENT);
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return this->u_.in_output_segment.offset_base;
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}
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// Return the symbol binding.
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elfcpp::STB
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binding() const
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{ return this->binding_; }
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// Return the symbol type.
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elfcpp::STT
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type() const
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{ return this->type_; }
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// Return the symbol visibility.
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elfcpp::STV
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visibility() const
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{ return this->visibility_; }
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// Set the visibility.
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void
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set_visibility(elfcpp::STV visibility)
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{ this->visibility_ = visibility; }
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// Override symbol visibility.
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void
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override_visibility(elfcpp::STV);
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// Return the non-visibility part of the st_other field.
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unsigned char
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nonvis() const
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{ return this->nonvis_; }
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// Return whether this symbol is a forwarder. This will never be
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// true of a symbol found in the hash table, but may be true of
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// symbol pointers attached to object files.
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bool
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is_forwarder() const
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{ return this->is_forwarder_; }
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// Mark this symbol as a forwarder.
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void
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set_forwarder()
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{ this->is_forwarder_ = true; }
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// Return whether this symbol has an alias in the weak aliases table
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// in Symbol_table.
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bool
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has_alias() const
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{ return this->has_alias_; }
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// Mark this symbol as having an alias.
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void
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set_has_alias()
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{ this->has_alias_ = true; }
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// Return whether this symbol needs an entry in the dynamic symbol
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// table.
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bool
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needs_dynsym_entry() const
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{
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return (this->needs_dynsym_entry_
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|| (this->in_reg() && this->in_dyn()));
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}
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// Mark this symbol as needing an entry in the dynamic symbol table.
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void
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set_needs_dynsym_entry()
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{ this->needs_dynsym_entry_ = true; }
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// Return whether this symbol should be added to the dynamic symbol
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// table.
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bool
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should_add_dynsym_entry() const;
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// Return whether this symbol has been seen in a regular object.
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bool
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in_reg() const
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{ return this->in_reg_; }
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// Mark this symbol as having been seen in a regular object.
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void
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set_in_reg()
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{ this->in_reg_ = true; }
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// Return whether this symbol has been seen in a dynamic object.
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bool
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in_dyn() const
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{ return this->in_dyn_; }
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// Mark this symbol as having been seen in a dynamic object.
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void
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set_in_dyn()
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{ this->in_dyn_ = true; }
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// Return whether this symbol has been seen in a real ELF object.
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// (IN_REG will return TRUE if the symbol has been seen in either
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// a real ELF object or an object claimed by a plugin.)
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bool
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in_real_elf() const
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{ return this->in_real_elf_; }
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// Mark this symbol as having been seen in a real ELF object.
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void
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set_in_real_elf()
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{ this->in_real_elf_ = true; }
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// Return the index of this symbol in the output file symbol table.
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// A value of -1U means that this symbol is not going into the
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// output file. This starts out as zero, and is set to a non-zero
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// value by Symbol_table::finalize. It is an error to ask for the
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// symbol table index before it has been set.
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unsigned int
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symtab_index() const
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{
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gold_assert(this->symtab_index_ != 0);
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return this->symtab_index_;
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}
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// Set the index of the symbol in the output file symbol table.
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void
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set_symtab_index(unsigned int index)
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{
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gold_assert(index != 0);
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this->symtab_index_ = index;
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}
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// Return whether this symbol already has an index in the output
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// file symbol table.
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bool
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has_symtab_index() const
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{ return this->symtab_index_ != 0; }
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// Return the index of this symbol in the dynamic symbol table. A
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// value of -1U means that this symbol is not going into the dynamic
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// symbol table. This starts out as zero, and is set to a non-zero
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// during Layout::finalize. It is an error to ask for the dynamic
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// symbol table index before it has been set.
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unsigned int
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dynsym_index() const
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{
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gold_assert(this->dynsym_index_ != 0);
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return this->dynsym_index_;
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}
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// Set the index of the symbol in the dynamic symbol table.
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void
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set_dynsym_index(unsigned int index)
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{
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gold_assert(index != 0);
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this->dynsym_index_ = index;
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}
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// Return whether this symbol already has an index in the dynamic
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// symbol table.
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bool
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has_dynsym_index() const
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{ return this->dynsym_index_ != 0; }
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// Return whether this symbol has an entry in the GOT section.
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// For a TLS symbol, this GOT entry will hold its tp-relative offset.
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bool
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has_got_offset(unsigned int got_type) const
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{ return this->got_offsets_.get_offset(got_type) != -1U; }
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// Return the offset into the GOT section of this symbol.
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unsigned int
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got_offset(unsigned int got_type) const
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{
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unsigned int got_offset = this->got_offsets_.get_offset(got_type);
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gold_assert(got_offset != -1U);
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return got_offset;
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}
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// Set the GOT offset of this symbol.
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void
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set_got_offset(unsigned int got_type, unsigned int got_offset)
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{ this->got_offsets_.set_offset(got_type, got_offset); }
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// Return whether this symbol has an entry in the PLT section.
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bool
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has_plt_offset() const
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{ return this->has_plt_offset_; }
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// Return the offset into the PLT section of this symbol.
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unsigned int
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plt_offset() const
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{
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gold_assert(this->has_plt_offset());
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return this->plt_offset_;
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}
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// Set the PLT offset of this symbol.
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void
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set_plt_offset(unsigned int plt_offset)
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{
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this->has_plt_offset_ = true;
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this->plt_offset_ = plt_offset;
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}
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// Return whether this dynamic symbol needs a special value in the
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// dynamic symbol table.
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bool
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needs_dynsym_value() const
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{ return this->needs_dynsym_value_; }
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// Set that this dynamic symbol needs a special value in the dynamic
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// symbol table.
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void
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set_needs_dynsym_value()
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{
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gold_assert(this->object()->is_dynamic());
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this->needs_dynsym_value_ = true;
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}
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// Return true if the final value of this symbol is known at link
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// time.
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bool
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final_value_is_known() const;
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// Return true if SHNDX represents a common symbol. This depends on
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// the target.
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static bool
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is_common_shndx(unsigned int shndx);
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// Return whether this is a defined symbol (not undefined or
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// common).
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bool
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is_defined() const
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{
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bool is_ordinary;
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if (this->source_ != FROM_OBJECT)
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return this->source_ != IS_UNDEFINED;
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unsigned int shndx = this->shndx(&is_ordinary);
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return (is_ordinary
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? shndx != elfcpp::SHN_UNDEF
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: !Symbol::is_common_shndx(shndx));
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}
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// Return true if this symbol is from a dynamic object.
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bool
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is_from_dynobj() const
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{
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return this->source_ == FROM_OBJECT && this->object()->is_dynamic();
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}
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// Return whether this is an undefined symbol.
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bool
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is_undefined() const
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{
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bool is_ordinary;
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return ((this->source_ == FROM_OBJECT
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&& this->shndx(&is_ordinary) == elfcpp::SHN_UNDEF
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&& is_ordinary)
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|| this->source_ == IS_UNDEFINED);
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}
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// Return whether this is a weak undefined symbol.
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bool
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is_weak_undefined() const
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{ return this->is_undefined() && this->binding() == elfcpp::STB_WEAK; }
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// Return whether this is an absolute symbol.
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bool
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is_absolute() const
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{
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bool is_ordinary;
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return ((this->source_ == FROM_OBJECT
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&& this->shndx(&is_ordinary) == elfcpp::SHN_ABS
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&& !is_ordinary)
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|| this->source_ == IS_CONSTANT);
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}
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// Return whether this is a common symbol.
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bool
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is_common() const
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{
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if (this->type_ == elfcpp::STT_COMMON)
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return true;
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if (this->source_ != FROM_OBJECT)
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return false;
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bool is_ordinary;
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unsigned int shndx = this->shndx(&is_ordinary);
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return !is_ordinary && Symbol::is_common_shndx(shndx);
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}
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// Return whether this symbol can be seen outside this object.
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bool
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is_externally_visible() const
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{
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return (this->visibility_ == elfcpp::STV_DEFAULT
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|| this->visibility_ == elfcpp::STV_PROTECTED);
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}
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// Return true if this symbol can be preempted by a definition in
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// another link unit.
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bool
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is_preemptible() const
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{
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// It doesn't make sense to ask whether a symbol defined in
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// another object is preemptible.
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gold_assert(!this->is_from_dynobj());
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// It doesn't make sense to ask whether an undefined symbol
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// is preemptible.
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gold_assert(!this->is_undefined());
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// If a symbol does not have default visibility, it can not be
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// seen outside this link unit and therefore is not preemptible.
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if (this->visibility_ != elfcpp::STV_DEFAULT)
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return false;
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// If this symbol has been forced to be a local symbol by a
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// version script, then it is not visible outside this link unit
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// and is not preemptible.
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if (this->is_forced_local_)
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return false;
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// If we are not producing a shared library, then nothing is
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// preemptible.
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if (!parameters->options().shared())
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return false;
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// If the user used -Bsymbolic, then nothing is preemptible.
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if (parameters->options().Bsymbolic())
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return false;
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// If the user used -Bsymbolic-functions, then functions are not
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// preemptible. We explicitly check for not being STT_OBJECT,
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// rather than for being STT_FUNC, because that is what the GNU
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// linker does.
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if (this->type() != elfcpp::STT_OBJECT
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&& parameters->options().Bsymbolic_functions())
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return false;
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// Otherwise the symbol is preemptible.
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return true;
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}
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// Return true if this symbol is a function that needs a PLT entry.
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// If the symbol is defined in a dynamic object or if it is subject
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// to pre-emption, we need to make a PLT entry. If we're doing a
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// static link or a -pie link, we don't create PLT entries.
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bool
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needs_plt_entry() const
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{
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// An undefined symbol from an executable does not need a PLT entry.
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if (this->is_undefined() && !parameters->options().shared())
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return false;
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return (!parameters->doing_static_link()
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&& !parameters->options().pie()
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&& this->type() == elfcpp::STT_FUNC
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&& (this->is_from_dynobj()
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|| this->is_undefined()
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|| this->is_preemptible()));
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}
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// When determining whether a reference to a symbol needs a dynamic
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// relocation, we need to know several things about the reference.
|
|
// These flags may be or'ed together.
|
|
enum Reference_flags
|
|
{
|
|
// Reference to the symbol's absolute address.
|
|
ABSOLUTE_REF = 1,
|
|
// A non-PIC reference.
|
|
NON_PIC_REF = 2,
|
|
// A function call.
|
|
FUNCTION_CALL = 4
|
|
};
|
|
|
|
// Given a direct absolute or pc-relative static relocation against
|
|
// the global symbol, this function returns whether a dynamic relocation
|
|
// is needed.
|
|
|
|
bool
|
|
needs_dynamic_reloc(int flags) const
|
|
{
|
|
// No dynamic relocations in a static link!
|
|
if (parameters->doing_static_link())
|
|
return false;
|
|
|
|
// A reference to an undefined symbol from an executable should be
|
|
// statically resolved to 0, and does not need a dynamic relocation.
|
|
// This matches gnu ld behavior.
|
|
if (this->is_undefined() && !parameters->options().shared())
|
|
return false;
|
|
|
|
// A reference to an absolute symbol does not need a dynamic relocation.
|
|
if (this->is_absolute())
|
|
return false;
|
|
|
|
// An absolute reference within a position-independent output file
|
|
// will need a dynamic relocation.
|
|
if ((flags & ABSOLUTE_REF)
|
|
&& parameters->options().output_is_position_independent())
|
|
return true;
|
|
|
|
// A function call that can branch to a local PLT entry does not need
|
|
// a dynamic relocation. A non-pic pc-relative function call in a
|
|
// shared library cannot use a PLT entry.
|
|
if ((flags & FUNCTION_CALL)
|
|
&& this->has_plt_offset()
|
|
&& !((flags & NON_PIC_REF) && parameters->options().shared()))
|
|
return false;
|
|
|
|
// A reference to any PLT entry in a non-position-independent executable
|
|
// does not need a dynamic relocation.
|
|
if (!parameters->options().output_is_position_independent()
|
|
&& this->has_plt_offset())
|
|
return false;
|
|
|
|
// A reference to a symbol defined in a dynamic object or to a
|
|
// symbol that is preemptible will need a dynamic relocation.
|
|
if (this->is_from_dynobj()
|
|
|| this->is_undefined()
|
|
|| this->is_preemptible())
|
|
return true;
|
|
|
|
// For all other cases, return FALSE.
|
|
return false;
|
|
}
|
|
|
|
// Whether we should use the PLT offset associated with a symbol for
|
|
// a relocation. IS_NON_PIC_REFERENCE is true if this is a non-PIC
|
|
// reloc--the same set of relocs for which we would pass NON_PIC_REF
|
|
// to the needs_dynamic_reloc function.
|
|
|
|
bool
|
|
use_plt_offset(bool is_non_pic_reference) const
|
|
{
|
|
// If the symbol doesn't have a PLT offset, then naturally we
|
|
// don't want to use it.
|
|
if (!this->has_plt_offset())
|
|
return false;
|
|
|
|
// If we are going to generate a dynamic relocation, then we will
|
|
// wind up using that, so no need to use the PLT entry.
|
|
if (this->needs_dynamic_reloc(FUNCTION_CALL
|
|
| (is_non_pic_reference
|
|
? NON_PIC_REF
|
|
: 0)))
|
|
return false;
|
|
|
|
// If the symbol is from a dynamic object, we need to use the PLT
|
|
// entry.
|
|
if (this->is_from_dynobj())
|
|
return true;
|
|
|
|
// If we are generating a shared object, and this symbol is
|
|
// undefined or preemptible, we need to use the PLT entry.
|
|
if (parameters->options().shared()
|
|
&& (this->is_undefined() || this->is_preemptible()))
|
|
return true;
|
|
|
|
// If this is a weak undefined symbol, we need to use the PLT
|
|
// entry; the symbol may be defined by a library loaded at
|
|
// runtime.
|
|
if (this->is_weak_undefined())
|
|
return true;
|
|
|
|
// Otherwise we can use the regular definition.
|
|
return false;
|
|
}
|
|
|
|
// Given a direct absolute static relocation against
|
|
// the global symbol, where a dynamic relocation is needed, this
|
|
// function returns whether a relative dynamic relocation can be used.
|
|
// The caller must determine separately whether the static relocation
|
|
// is compatible with a relative relocation.
|
|
|
|
bool
|
|
can_use_relative_reloc(bool is_function_call) const
|
|
{
|
|
// A function call that can branch to a local PLT entry can
|
|
// use a RELATIVE relocation.
|
|
if (is_function_call && this->has_plt_offset())
|
|
return true;
|
|
|
|
// A reference to a symbol defined in a dynamic object or to a
|
|
// symbol that is preemptible can not use a RELATIVE relocaiton.
|
|
if (this->is_from_dynobj()
|
|
|| this->is_undefined()
|
|
|| this->is_preemptible())
|
|
return false;
|
|
|
|
// For all other cases, return TRUE.
|
|
return true;
|
|
}
|
|
|
|
// Return the output section where this symbol is defined. Return
|
|
// NULL if the symbol has an absolute value.
|
|
Output_section*
|
|
output_section() const;
|
|
|
|
// Set the symbol's output section. This is used for symbols
|
|
// defined in scripts. This should only be called after the symbol
|
|
// table has been finalized.
|
|
void
|
|
set_output_section(Output_section*);
|
|
|
|
// Return whether there should be a warning for references to this
|
|
// symbol.
|
|
bool
|
|
has_warning() const
|
|
{ return this->has_warning_; }
|
|
|
|
// Mark this symbol as having a warning.
|
|
void
|
|
set_has_warning()
|
|
{ this->has_warning_ = true; }
|
|
|
|
// Return whether this symbol is defined by a COPY reloc from a
|
|
// dynamic object.
|
|
bool
|
|
is_copied_from_dynobj() const
|
|
{ return this->is_copied_from_dynobj_; }
|
|
|
|
// Mark this symbol as defined by a COPY reloc.
|
|
void
|
|
set_is_copied_from_dynobj()
|
|
{ this->is_copied_from_dynobj_ = true; }
|
|
|
|
// Return whether this symbol is forced to visibility STB_LOCAL
|
|
// by a "local:" entry in a version script.
|
|
bool
|
|
is_forced_local() const
|
|
{ return this->is_forced_local_; }
|
|
|
|
// Mark this symbol as forced to STB_LOCAL visibility.
|
|
void
|
|
set_is_forced_local()
|
|
{ this->is_forced_local_ = true; }
|
|
|
|
// Return true if this may need a COPY relocation.
|
|
// References from an executable object to non-function symbols
|
|
// defined in a dynamic object may need a COPY relocation.
|
|
bool
|
|
may_need_copy_reloc() const
|
|
{
|
|
return (!parameters->options().shared()
|
|
&& parameters->options().copyreloc()
|
|
&& this->is_from_dynobj()
|
|
&& this->type() != elfcpp::STT_FUNC);
|
|
}
|
|
|
|
protected:
|
|
// Instances of this class should always be created at a specific
|
|
// size.
|
|
Symbol()
|
|
{ memset(this, 0, sizeof *this); }
|
|
|
|
// Initialize the general fields.
|
|
void
|
|
init_fields(const char* name, const char* version,
|
|
elfcpp::STT type, elfcpp::STB binding,
|
|
elfcpp::STV visibility, unsigned char nonvis);
|
|
|
|
// Initialize fields from an ELF symbol in OBJECT. ST_SHNDX is the
|
|
// section index, IS_ORDINARY is whether it is a normal section
|
|
// index rather than a special code.
|
|
template<int size, bool big_endian>
|
|
void
|
|
init_base_object(const char *name, const char* version, Object* object,
|
|
const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
|
|
bool is_ordinary);
|
|
|
|
// Initialize fields for an Output_data.
|
|
void
|
|
init_base_output_data(const char* name, const char* version, Output_data*,
|
|
elfcpp::STT, elfcpp::STB, elfcpp::STV,
|
|
unsigned char nonvis, bool offset_is_from_end);
|
|
|
|
// Initialize fields for an Output_segment.
|
|
void
|
|
init_base_output_segment(const char* name, const char* version,
|
|
Output_segment* os, elfcpp::STT type,
|
|
elfcpp::STB binding, elfcpp::STV visibility,
|
|
unsigned char nonvis,
|
|
Segment_offset_base offset_base);
|
|
|
|
// Initialize fields for a constant.
|
|
void
|
|
init_base_constant(const char* name, const char* version, elfcpp::STT type,
|
|
elfcpp::STB binding, elfcpp::STV visibility,
|
|
unsigned char nonvis);
|
|
|
|
// Initialize fields for an undefined symbol.
|
|
void
|
|
init_base_undefined(const char* name, const char* version, elfcpp::STT type,
|
|
elfcpp::STB binding, elfcpp::STV visibility,
|
|
unsigned char nonvis);
|
|
|
|
// Override existing symbol.
|
|
template<int size, bool big_endian>
|
|
void
|
|
override_base(const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
|
|
bool is_ordinary, Object* object, const char* version);
|
|
|
|
// Override existing symbol with a special symbol.
|
|
void
|
|
override_base_with_special(const Symbol* from);
|
|
|
|
// Override symbol version.
|
|
void
|
|
override_version(const char* version);
|
|
|
|
// Allocate a common symbol by giving it a location in the output
|
|
// file.
|
|
void
|
|
allocate_base_common(Output_data*);
|
|
|
|
private:
|
|
Symbol(const Symbol&);
|
|
Symbol& operator=(const Symbol&);
|
|
|
|
// Symbol name (expected to point into a Stringpool).
|
|
const char* name_;
|
|
// Symbol version (expected to point into a Stringpool). This may
|
|
// be NULL.
|
|
const char* version_;
|
|
|
|
union
|
|
{
|
|
// This struct is used if SOURCE_ == FROM_OBJECT.
|
|
struct
|
|
{
|
|
// Object in which symbol is defined, or in which it was first
|
|
// seen.
|
|
Object* object;
|
|
// Section number in object_ in which symbol is defined.
|
|
unsigned int shndx;
|
|
} from_object;
|
|
|
|
// This struct is used if SOURCE_ == IN_OUTPUT_DATA.
|
|
struct
|
|
{
|
|
// Output_data in which symbol is defined. Before
|
|
// Layout::finalize the symbol's value is an offset within the
|
|
// Output_data.
|
|
Output_data* output_data;
|
|
// True if the offset is from the end, false if the offset is
|
|
// from the beginning.
|
|
bool offset_is_from_end;
|
|
} in_output_data;
|
|
|
|
// This struct is used if SOURCE_ == IN_OUTPUT_SEGMENT.
|
|
struct
|
|
{
|
|
// Output_segment in which the symbol is defined. Before
|
|
// Layout::finalize the symbol's value is an offset.
|
|
Output_segment* output_segment;
|
|
// The base to use for the offset before Layout::finalize.
|
|
Segment_offset_base offset_base;
|
|
} in_output_segment;
|
|
} u_;
|
|
|
|
// The index of this symbol in the output file. If the symbol is
|
|
// not going into the output file, this value is -1U. This field
|
|
// starts as always holding zero. It is set to a non-zero value by
|
|
// Symbol_table::finalize.
|
|
unsigned int symtab_index_;
|
|
|
|
// The index of this symbol in the dynamic symbol table. If the
|
|
// symbol is not going into the dynamic symbol table, this value is
|
|
// -1U. This field starts as always holding zero. It is set to a
|
|
// non-zero value during Layout::finalize.
|
|
unsigned int dynsym_index_;
|
|
|
|
// If this symbol has an entry in the GOT section (has_got_offset_
|
|
// is true), this holds the offset from the start of the GOT section.
|
|
// A symbol may have more than one GOT offset (e.g., when mixing
|
|
// modules compiled with two different TLS models), but will usually
|
|
// have at most one.
|
|
Got_offset_list got_offsets_;
|
|
|
|
// If this symbol has an entry in the PLT section (has_plt_offset_
|
|
// is true), then this is the offset from the start of the PLT
|
|
// section.
|
|
unsigned int plt_offset_;
|
|
|
|
// Symbol type (bits 0 to 3).
|
|
elfcpp::STT type_ : 4;
|
|
// Symbol binding (bits 4 to 7).
|
|
elfcpp::STB binding_ : 4;
|
|
// Symbol visibility (bits 8 to 9).
|
|
elfcpp::STV visibility_ : 2;
|
|
// Rest of symbol st_other field (bits 10 to 15).
|
|
unsigned int nonvis_ : 6;
|
|
// The type of symbol (bits 16 to 18).
|
|
Source source_ : 3;
|
|
// True if this symbol always requires special target-specific
|
|
// handling (bit 19).
|
|
bool is_target_special_ : 1;
|
|
// True if this is the default version of the symbol (bit 20).
|
|
bool is_def_ : 1;
|
|
// True if this symbol really forwards to another symbol. This is
|
|
// used when we discover after the fact that two different entries
|
|
// in the hash table really refer to the same symbol. This will
|
|
// never be set for a symbol found in the hash table, but may be set
|
|
// for a symbol found in the list of symbols attached to an Object.
|
|
// It forwards to the symbol found in the forwarders_ map of
|
|
// Symbol_table (bit 21).
|
|
bool is_forwarder_ : 1;
|
|
// True if the symbol has an alias in the weak_aliases table in
|
|
// Symbol_table (bit 22).
|
|
bool has_alias_ : 1;
|
|
// True if this symbol needs to be in the dynamic symbol table (bit
|
|
// 23).
|
|
bool needs_dynsym_entry_ : 1;
|
|
// True if we've seen this symbol in a regular object (bit 24).
|
|
bool in_reg_ : 1;
|
|
// True if we've seen this symbol in a dynamic object (bit 25).
|
|
bool in_dyn_ : 1;
|
|
// True if the symbol has an entry in the PLT section (bit 26).
|
|
bool has_plt_offset_ : 1;
|
|
// True if this is a dynamic symbol which needs a special value in
|
|
// the dynamic symbol table (bit 27).
|
|
bool needs_dynsym_value_ : 1;
|
|
// True if there is a warning for this symbol (bit 28).
|
|
bool has_warning_ : 1;
|
|
// True if we are using a COPY reloc for this symbol, so that the
|
|
// real definition lives in a dynamic object (bit 29).
|
|
bool is_copied_from_dynobj_ : 1;
|
|
// True if this symbol was forced to local visibility by a version
|
|
// script (bit 30).
|
|
bool is_forced_local_ : 1;
|
|
// True if the field u_.from_object.shndx is an ordinary section
|
|
// index, not one of the special codes from SHN_LORESERVE to
|
|
// SHN_HIRESERVE (bit 31).
|
|
bool is_ordinary_shndx_ : 1;
|
|
// True if we've seen this symbol in a real ELF object.
|
|
bool in_real_elf_ : 1;
|
|
};
|
|
|
|
// The parts of a symbol which are size specific. Using a template
|
|
// derived class like this helps us use less space on a 32-bit system.
|
|
|
|
template<int size>
|
|
class Sized_symbol : public Symbol
|
|
{
|
|
public:
|
|
typedef typename elfcpp::Elf_types<size>::Elf_Addr Value_type;
|
|
typedef typename elfcpp::Elf_types<size>::Elf_WXword Size_type;
|
|
|
|
Sized_symbol()
|
|
{ }
|
|
|
|
// Initialize fields from an ELF symbol in OBJECT. ST_SHNDX is the
|
|
// section index, IS_ORDINARY is whether it is a normal section
|
|
// index rather than a special code.
|
|
template<bool big_endian>
|
|
void
|
|
init_object(const char *name, const char* version, Object* object,
|
|
const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
|
|
bool is_ordinary);
|
|
|
|
// Initialize fields for an Output_data.
|
|
void
|
|
init_output_data(const char* name, const char* version, Output_data*,
|
|
Value_type value, Size_type symsize, elfcpp::STT,
|
|
elfcpp::STB, elfcpp::STV, unsigned char nonvis,
|
|
bool offset_is_from_end);
|
|
|
|
// Initialize fields for an Output_segment.
|
|
void
|
|
init_output_segment(const char* name, const char* version, Output_segment*,
|
|
Value_type value, Size_type symsize, elfcpp::STT,
|
|
elfcpp::STB, elfcpp::STV, unsigned char nonvis,
|
|
Segment_offset_base offset_base);
|
|
|
|
// Initialize fields for a constant.
|
|
void
|
|
init_constant(const char* name, const char* version, Value_type value,
|
|
Size_type symsize, elfcpp::STT, elfcpp::STB, elfcpp::STV,
|
|
unsigned char nonvis);
|
|
|
|
// Initialize fields for an undefined symbol.
|
|
void
|
|
init_undefined(const char* name, const char* version, elfcpp::STT,
|
|
elfcpp::STB, elfcpp::STV, unsigned char nonvis);
|
|
|
|
// Override existing symbol.
|
|
template<bool big_endian>
|
|
void
|
|
override(const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
|
|
bool is_ordinary, Object* object, const char* version);
|
|
|
|
// Override existing symbol with a special symbol.
|
|
void
|
|
override_with_special(const Sized_symbol<size>*);
|
|
|
|
// Return the symbol's value.
|
|
Value_type
|
|
value() const
|
|
{ return this->value_; }
|
|
|
|
// Return the symbol's size (we can't call this 'size' because that
|
|
// is a template parameter).
|
|
Size_type
|
|
symsize() const
|
|
{ return this->symsize_; }
|
|
|
|
// Set the symbol size. This is used when resolving common symbols.
|
|
void
|
|
set_symsize(Size_type symsize)
|
|
{ this->symsize_ = symsize; }
|
|
|
|
// Set the symbol value. This is called when we store the final
|
|
// values of the symbols into the symbol table.
|
|
void
|
|
set_value(Value_type value)
|
|
{ this->value_ = value; }
|
|
|
|
// Allocate a common symbol by giving it a location in the output
|
|
// file.
|
|
void
|
|
allocate_common(Output_data*, Value_type value);
|
|
|
|
private:
|
|
Sized_symbol(const Sized_symbol&);
|
|
Sized_symbol& operator=(const Sized_symbol&);
|
|
|
|
// Symbol value. Before Layout::finalize this is the offset in the
|
|
// input section. This is set to the final value during
|
|
// Layout::finalize.
|
|
Value_type value_;
|
|
// Symbol size.
|
|
Size_type symsize_;
|
|
};
|
|
|
|
// A struct describing a symbol defined by the linker, where the value
|
|
// of the symbol is defined based on an output section. This is used
|
|
// for symbols defined by the linker, like "_init_array_start".
|
|
|
|
struct Define_symbol_in_section
|
|
{
|
|
// The symbol name.
|
|
const char* name;
|
|
// The name of the output section with which this symbol should be
|
|
// associated. If there is no output section with that name, the
|
|
// symbol will be defined as zero.
|
|
const char* output_section;
|
|
// The offset of the symbol within the output section. This is an
|
|
// offset from the start of the output section, unless start_at_end
|
|
// is true, in which case this is an offset from the end of the
|
|
// output section.
|
|
uint64_t value;
|
|
// The size of the symbol.
|
|
uint64_t size;
|
|
// The symbol type.
|
|
elfcpp::STT type;
|
|
// The symbol binding.
|
|
elfcpp::STB binding;
|
|
// The symbol visibility.
|
|
elfcpp::STV visibility;
|
|
// The rest of the st_other field.
|
|
unsigned char nonvis;
|
|
// If true, the value field is an offset from the end of the output
|
|
// section.
|
|
bool offset_is_from_end;
|
|
// If true, this symbol is defined only if we see a reference to it.
|
|
bool only_if_ref;
|
|
};
|
|
|
|
// A struct describing a symbol defined by the linker, where the value
|
|
// of the symbol is defined based on a segment. This is used for
|
|
// symbols defined by the linker, like "_end". We describe the
|
|
// segment with which the symbol should be associated by its
|
|
// characteristics. If no segment meets these characteristics, the
|
|
// symbol will be defined as zero. If there is more than one segment
|
|
// which meets these characteristics, we will use the first one.
|
|
|
|
struct Define_symbol_in_segment
|
|
{
|
|
// The symbol name.
|
|
const char* name;
|
|
// The segment type where the symbol should be defined, typically
|
|
// PT_LOAD.
|
|
elfcpp::PT segment_type;
|
|
// Bitmask of segment flags which must be set.
|
|
elfcpp::PF segment_flags_set;
|
|
// Bitmask of segment flags which must be clear.
|
|
elfcpp::PF segment_flags_clear;
|
|
// The offset of the symbol within the segment. The offset is
|
|
// calculated from the position set by offset_base.
|
|
uint64_t value;
|
|
// The size of the symbol.
|
|
uint64_t size;
|
|
// The symbol type.
|
|
elfcpp::STT type;
|
|
// The symbol binding.
|
|
elfcpp::STB binding;
|
|
// The symbol visibility.
|
|
elfcpp::STV visibility;
|
|
// The rest of the st_other field.
|
|
unsigned char nonvis;
|
|
// The base from which we compute the offset.
|
|
Symbol::Segment_offset_base offset_base;
|
|
// If true, this symbol is defined only if we see a reference to it.
|
|
bool only_if_ref;
|
|
};
|
|
|
|
// This class manages warnings. Warnings are a GNU extension. When
|
|
// we see a section named .gnu.warning.SYM in an object file, and if
|
|
// we wind using the definition of SYM from that object file, then we
|
|
// will issue a warning for any relocation against SYM from a
|
|
// different object file. The text of the warning is the contents of
|
|
// the section. This is not precisely the definition used by the old
|
|
// GNU linker; the old GNU linker treated an occurrence of
|
|
// .gnu.warning.SYM as defining a warning symbol. A warning symbol
|
|
// would trigger a warning on any reference. However, it was
|
|
// inconsistent in that a warning in a dynamic object only triggered
|
|
// if there was no definition in a regular object. This linker is
|
|
// different in that we only issue a warning if we use the symbol
|
|
// definition from the same object file as the warning section.
|
|
|
|
class Warnings
|
|
{
|
|
public:
|
|
Warnings()
|
|
: warnings_()
|
|
{ }
|
|
|
|
// Add a warning for symbol NAME in object OBJ. WARNING is the text
|
|
// of the warning.
|
|
void
|
|
add_warning(Symbol_table* symtab, const char* name, Object* obj,
|
|
const std::string& warning);
|
|
|
|
// For each symbol for which we should give a warning, make a note
|
|
// on the symbol.
|
|
void
|
|
note_warnings(Symbol_table* symtab);
|
|
|
|
// Issue a warning for a reference to SYM at RELINFO's location.
|
|
template<int size, bool big_endian>
|
|
void
|
|
issue_warning(const Symbol* sym, const Relocate_info<size, big_endian>*,
|
|
size_t relnum, off_t reloffset) const;
|
|
|
|
private:
|
|
Warnings(const Warnings&);
|
|
Warnings& operator=(const Warnings&);
|
|
|
|
// What we need to know to get the warning text.
|
|
struct Warning_location
|
|
{
|
|
// The object the warning is in.
|
|
Object* object;
|
|
// The warning text.
|
|
std::string text;
|
|
|
|
Warning_location()
|
|
: object(NULL), text()
|
|
{ }
|
|
|
|
void
|
|
set(Object* o, const std::string& t)
|
|
{
|
|
this->object = o;
|
|
this->text = t;
|
|
}
|
|
};
|
|
|
|
// A mapping from warning symbol names (canonicalized in
|
|
// Symbol_table's namepool_ field) to warning information.
|
|
typedef Unordered_map<const char*, Warning_location> Warning_table;
|
|
|
|
Warning_table warnings_;
|
|
};
|
|
|
|
// The main linker symbol table.
|
|
|
|
class Symbol_table
|
|
{
|
|
public:
|
|
// COUNT is an estimate of how many symbosl will be inserted in the
|
|
// symbol table. It's ok to put 0 if you don't know; a correct
|
|
// guess will just save some CPU by reducing hashtable resizes.
|
|
Symbol_table(unsigned int count, const Version_script_info& version_script);
|
|
|
|
~Symbol_table();
|
|
|
|
void
|
|
set_icf(Icf* icf)
|
|
{ this->icf_ = icf;}
|
|
|
|
Icf*
|
|
icf() const
|
|
{ return this->icf_; }
|
|
|
|
// Returns true if ICF determined that this is a duplicate section.
|
|
bool
|
|
is_section_folded(Object* obj, unsigned int shndx) const;
|
|
|
|
void
|
|
set_gc(Garbage_collection* gc)
|
|
{ this->gc_ = gc; }
|
|
|
|
Garbage_collection*
|
|
gc() const
|
|
{ return this->gc_; }
|
|
|
|
// During garbage collection, this keeps undefined symbols.
|
|
void
|
|
gc_mark_undef_symbols();
|
|
|
|
// During garbage collection, this ensures externally visible symbols
|
|
// are not treated as garbage while building shared objects.
|
|
void
|
|
gc_mark_symbol_for_shlib(Symbol* sym);
|
|
|
|
// During garbage collection, this keeps sections that correspond to
|
|
// symbols seen in dynamic objects.
|
|
inline void
|
|
gc_mark_dyn_syms(Symbol* sym);
|
|
|
|
// Add COUNT external symbols from the relocatable object RELOBJ to
|
|
// the symbol table. SYMS is the symbols, SYMNDX_OFFSET is the
|
|
// offset in the symbol table of the first symbol, SYM_NAMES is
|
|
// their names, SYM_NAME_SIZE is the size of SYM_NAMES. This sets
|
|
// SYMPOINTERS to point to the symbols in the symbol table. It sets
|
|
// *DEFINED to the number of defined symbols.
|
|
template<int size, bool big_endian>
|
|
void
|
|
add_from_relobj(Sized_relobj<size, big_endian>* relobj,
|
|
const unsigned char* syms, size_t count,
|
|
size_t symndx_offset, const char* sym_names,
|
|
size_t sym_name_size,
|
|
typename Sized_relobj<size, big_endian>::Symbols*,
|
|
size_t* defined);
|
|
|
|
// Add one external symbol from the plugin object OBJ to the symbol table.
|
|
// Returns a pointer to the resolved symbol in the symbol table.
|
|
template<int size, bool big_endian>
|
|
Symbol*
|
|
add_from_pluginobj(Sized_pluginobj<size, big_endian>* obj,
|
|
const char* name, const char* ver,
|
|
elfcpp::Sym<size, big_endian>* sym);
|
|
|
|
// Add COUNT dynamic symbols from the dynamic object DYNOBJ to the
|
|
// symbol table. SYMS is the symbols. SYM_NAMES is their names.
|
|
// SYM_NAME_SIZE is the size of SYM_NAMES. The other parameters are
|
|
// symbol version data.
|
|
template<int size, bool big_endian>
|
|
void
|
|
add_from_dynobj(Sized_dynobj<size, big_endian>* dynobj,
|
|
const unsigned char* syms, size_t count,
|
|
const char* sym_names, size_t sym_name_size,
|
|
const unsigned char* versym, size_t versym_size,
|
|
const std::vector<const char*>*,
|
|
typename Sized_relobj<size, big_endian>::Symbols*,
|
|
size_t* defined);
|
|
|
|
// Define a special symbol based on an Output_data. It is a
|
|
// multiple definition error if this symbol is already defined.
|
|
Symbol*
|
|
define_in_output_data(const char* name, const char* version,
|
|
Output_data*, uint64_t value, uint64_t symsize,
|
|
elfcpp::STT type, elfcpp::STB binding,
|
|
elfcpp::STV visibility, unsigned char nonvis,
|
|
bool offset_is_from_end, bool only_if_ref);
|
|
|
|
// Define a special symbol based on an Output_segment. It is a
|
|
// multiple definition error if this symbol is already defined.
|
|
Symbol*
|
|
define_in_output_segment(const char* name, const char* version,
|
|
Output_segment*, uint64_t value, uint64_t symsize,
|
|
elfcpp::STT type, elfcpp::STB binding,
|
|
elfcpp::STV visibility, unsigned char nonvis,
|
|
Symbol::Segment_offset_base, bool only_if_ref);
|
|
|
|
// Define a special symbol with a constant value. It is a multiple
|
|
// definition error if this symbol is already defined.
|
|
Symbol*
|
|
define_as_constant(const char* name, const char* version,
|
|
uint64_t value, uint64_t symsize, elfcpp::STT type,
|
|
elfcpp::STB binding, elfcpp::STV visibility,
|
|
unsigned char nonvis, bool only_if_ref,
|
|
bool force_override);
|
|
|
|
// Define a set of symbols in output sections. If ONLY_IF_REF is
|
|
// true, only define them if they are referenced.
|
|
void
|
|
define_symbols(const Layout*, int count, const Define_symbol_in_section*,
|
|
bool only_if_ref);
|
|
|
|
// Define a set of symbols in output segments. If ONLY_IF_REF is
|
|
// true, only defined them if they are referenced.
|
|
void
|
|
define_symbols(const Layout*, int count, const Define_symbol_in_segment*,
|
|
bool only_if_ref);
|
|
|
|
// Define SYM using a COPY reloc. POSD is the Output_data where the
|
|
// symbol should be defined--typically a .dyn.bss section. VALUE is
|
|
// the offset within POSD.
|
|
template<int size>
|
|
void
|
|
define_with_copy_reloc(Sized_symbol<size>* sym, Output_data* posd,
|
|
typename elfcpp::Elf_types<size>::Elf_Addr);
|
|
|
|
// Look up a symbol.
|
|
Symbol*
|
|
lookup(const char*, const char* version = NULL) const;
|
|
|
|
// Return the real symbol associated with the forwarder symbol FROM.
|
|
Symbol*
|
|
resolve_forwards(const Symbol* from) const;
|
|
|
|
// Return the sized version of a symbol in this table.
|
|
template<int size>
|
|
Sized_symbol<size>*
|
|
get_sized_symbol(Symbol*) const;
|
|
|
|
template<int size>
|
|
const Sized_symbol<size>*
|
|
get_sized_symbol(const Symbol*) const;
|
|
|
|
// Return the count of undefined symbols seen.
|
|
int
|
|
saw_undefined() const
|
|
{ return this->saw_undefined_; }
|
|
|
|
// Allocate the common symbols
|
|
void
|
|
allocate_commons(Layout*, Mapfile*);
|
|
|
|
// Add a warning for symbol NAME in object OBJ. WARNING is the text
|
|
// of the warning.
|
|
void
|
|
add_warning(const char* name, Object* obj, const std::string& warning)
|
|
{ this->warnings_.add_warning(this, name, obj, warning); }
|
|
|
|
// Canonicalize a symbol name for use in the hash table.
|
|
const char*
|
|
canonicalize_name(const char* name)
|
|
{ return this->namepool_.add(name, true, NULL); }
|
|
|
|
// Possibly issue a warning for a reference to SYM at LOCATION which
|
|
// is in OBJ.
|
|
template<int size, bool big_endian>
|
|
void
|
|
issue_warning(const Symbol* sym,
|
|
const Relocate_info<size, big_endian>* relinfo,
|
|
size_t relnum, off_t reloffset) const
|
|
{ this->warnings_.issue_warning(sym, relinfo, relnum, reloffset); }
|
|
|
|
// Check candidate_odr_violations_ to find symbols with the same name
|
|
// but apparently different definitions (different source-file/line-no).
|
|
void
|
|
detect_odr_violations(const Task*, const char* output_file_name) const;
|
|
|
|
// Add any undefined symbols named on the command line to the symbol
|
|
// table.
|
|
void
|
|
add_undefined_symbols_from_command_line();
|
|
|
|
// SYM is defined using a COPY reloc. Return the dynamic object
|
|
// where the original definition was found.
|
|
Dynobj*
|
|
get_copy_source(const Symbol* sym) const;
|
|
|
|
// Set the dynamic symbol indexes. INDEX is the index of the first
|
|
// global dynamic symbol. Pointers to the symbols are stored into
|
|
// the vector. The names are stored into the Stringpool. This
|
|
// returns an updated dynamic symbol index.
|
|
unsigned int
|
|
set_dynsym_indexes(unsigned int index, std::vector<Symbol*>*,
|
|
Stringpool*, Versions*);
|
|
|
|
// Finalize the symbol table after we have set the final addresses
|
|
// of all the input sections. This sets the final symbol indexes,
|
|
// values and adds the names to *POOL. *PLOCAL_SYMCOUNT is the
|
|
// index of the first global symbol. OFF is the file offset of the
|
|
// global symbol table, DYNOFF is the offset of the globals in the
|
|
// dynamic symbol table, DYN_GLOBAL_INDEX is the index of the first
|
|
// global dynamic symbol, and DYNCOUNT is the number of global
|
|
// dynamic symbols. This records the parameters, and returns the
|
|
// new file offset. It updates *PLOCAL_SYMCOUNT if it created any
|
|
// local symbols.
|
|
off_t
|
|
finalize(off_t off, off_t dynoff, size_t dyn_global_index, size_t dyncount,
|
|
Stringpool* pool, unsigned int *plocal_symcount);
|
|
|
|
// Status code of Symbol_table::compute_final_value.
|
|
enum Compute_final_value_status
|
|
{
|
|
// No error.
|
|
CFVS_OK,
|
|
// Unspported symbol section.
|
|
CFVS_UNSUPPORTED_SYMBOL_SECTION,
|
|
// No output section.
|
|
CFVS_NO_OUTPUT_SECTION
|
|
};
|
|
|
|
// Compute the final value of SYM and store status in location PSTATUS.
|
|
// During relaxation, this may be called multiple times for a symbol to
|
|
// compute its would-be final value in each relaxation pass.
|
|
|
|
template<int size>
|
|
typename Sized_symbol<size>::Value_type
|
|
compute_final_value(const Sized_symbol<size>* sym,
|
|
Compute_final_value_status* pstatus) const;
|
|
|
|
// Write out the global symbols.
|
|
void
|
|
write_globals(const Stringpool*, const Stringpool*,
|
|
Output_symtab_xindex*, Output_symtab_xindex*,
|
|
Output_file*) const;
|
|
|
|
// Write out a section symbol. Return the updated offset.
|
|
void
|
|
write_section_symbol(const Output_section*, Output_symtab_xindex*,
|
|
Output_file*, off_t) const;
|
|
|
|
// Dump statistical information to stderr.
|
|
void
|
|
print_stats() const;
|
|
|
|
// Return the version script information.
|
|
const Version_script_info&
|
|
version_script() const
|
|
{ return version_script_; }
|
|
|
|
private:
|
|
Symbol_table(const Symbol_table&);
|
|
Symbol_table& operator=(const Symbol_table&);
|
|
|
|
// The type of the list of common symbols.
|
|
typedef std::vector<Symbol*> Commons_type;
|
|
|
|
// The type of the symbol hash table.
|
|
|
|
typedef std::pair<Stringpool::Key, Stringpool::Key> Symbol_table_key;
|
|
|
|
struct Symbol_table_hash
|
|
{
|
|
size_t
|
|
operator()(const Symbol_table_key&) const;
|
|
};
|
|
|
|
struct Symbol_table_eq
|
|
{
|
|
bool
|
|
operator()(const Symbol_table_key&, const Symbol_table_key&) const;
|
|
};
|
|
|
|
typedef Unordered_map<Symbol_table_key, Symbol*, Symbol_table_hash,
|
|
Symbol_table_eq> Symbol_table_type;
|
|
|
|
// Make FROM a forwarder symbol to TO.
|
|
void
|
|
make_forwarder(Symbol* from, Symbol* to);
|
|
|
|
// Add a symbol.
|
|
template<int size, bool big_endian>
|
|
Sized_symbol<size>*
|
|
add_from_object(Object*, const char *name, Stringpool::Key name_key,
|
|
const char *version, Stringpool::Key version_key,
|
|
bool def, const elfcpp::Sym<size, big_endian>& sym,
|
|
unsigned int st_shndx, bool is_ordinary,
|
|
unsigned int orig_st_shndx);
|
|
|
|
// Define a default symbol.
|
|
template<int size, bool big_endian>
|
|
void
|
|
define_default_version(Sized_symbol<size>*, bool,
|
|
Symbol_table_type::iterator);
|
|
|
|
// Resolve symbols.
|
|
template<int size, bool big_endian>
|
|
void
|
|
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*, const char* version);
|
|
|
|
template<int size, bool big_endian>
|
|
void
|
|
resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from);
|
|
|
|
// Record that a symbol is forced to be local by a version script or
|
|
// by visibility.
|
|
void
|
|
force_local(Symbol*);
|
|
|
|
// Adjust NAME and *NAME_KEY for wrapping.
|
|
const char*
|
|
wrap_symbol(const char* name, Stringpool::Key* name_key);
|
|
|
|
// Whether we should override a symbol, based on flags in
|
|
// resolve.cc.
|
|
static bool
|
|
should_override(const Symbol*, unsigned int, Object*, bool*);
|
|
|
|
// Report a problem in symbol resolution.
|
|
static void
|
|
report_resolve_problem(bool is_error, const char* msg, const Symbol* to,
|
|
Object* object);
|
|
|
|
// Override a symbol.
|
|
template<int size, bool big_endian>
|
|
void
|
|
override(Sized_symbol<size>* tosym,
|
|
const elfcpp::Sym<size, big_endian>& fromsym,
|
|
unsigned int st_shndx, bool is_ordinary,
|
|
Object* object, const char* version);
|
|
|
|
// Whether we should override a symbol with a special symbol which
|
|
// is automatically defined by the linker.
|
|
static bool
|
|
should_override_with_special(const Symbol*);
|
|
|
|
// Override a symbol with a special symbol.
|
|
template<int size>
|
|
void
|
|
override_with_special(Sized_symbol<size>* tosym,
|
|
const Sized_symbol<size>* fromsym);
|
|
|
|
// Record all weak alias sets for a dynamic object.
|
|
template<int size>
|
|
void
|
|
record_weak_aliases(std::vector<Sized_symbol<size>*>*);
|
|
|
|
// Define a special symbol.
|
|
template<int size, bool big_endian>
|
|
Sized_symbol<size>*
|
|
define_special_symbol(const char** pname, const char** pversion,
|
|
bool only_if_ref, Sized_symbol<size>** poldsym,
|
|
bool* resolve_oldsym);
|
|
|
|
// Define a symbol in an Output_data, sized version.
|
|
template<int size>
|
|
Sized_symbol<size>*
|
|
do_define_in_output_data(const char* name, const char* version, Output_data*,
|
|
typename elfcpp::Elf_types<size>::Elf_Addr value,
|
|
typename elfcpp::Elf_types<size>::Elf_WXword ssize,
|
|
elfcpp::STT type, elfcpp::STB binding,
|
|
elfcpp::STV visibility, unsigned char nonvis,
|
|
bool offset_is_from_end, bool only_if_ref);
|
|
|
|
// Define a symbol in an Output_segment, sized version.
|
|
template<int size>
|
|
Sized_symbol<size>*
|
|
do_define_in_output_segment(
|
|
const char* name, const char* version, Output_segment* os,
|
|
typename elfcpp::Elf_types<size>::Elf_Addr value,
|
|
typename elfcpp::Elf_types<size>::Elf_WXword ssize,
|
|
elfcpp::STT type, elfcpp::STB binding,
|
|
elfcpp::STV visibility, unsigned char nonvis,
|
|
Symbol::Segment_offset_base offset_base, bool only_if_ref);
|
|
|
|
// Define a symbol as a constant, sized version.
|
|
template<int size>
|
|
Sized_symbol<size>*
|
|
do_define_as_constant(
|
|
const char* name, const char* version,
|
|
typename elfcpp::Elf_types<size>::Elf_Addr value,
|
|
typename elfcpp::Elf_types<size>::Elf_WXword ssize,
|
|
elfcpp::STT type, elfcpp::STB binding,
|
|
elfcpp::STV visibility, unsigned char nonvis,
|
|
bool only_if_ref, bool force_override);
|
|
|
|
// Add any undefined symbols named on the command line to the symbol
|
|
// table, sized version.
|
|
template<int size>
|
|
void
|
|
do_add_undefined_symbols_from_command_line();
|
|
|
|
// Types of common symbols.
|
|
|
|
enum Commons_section_type
|
|
{
|
|
COMMONS_NORMAL,
|
|
COMMONS_TLS,
|
|
COMMONS_SMALL,
|
|
COMMONS_LARGE
|
|
};
|
|
|
|
// Allocate the common symbols, sized version.
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template<int size>
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|
void
|
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do_allocate_commons(Layout*, Mapfile*);
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|
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// Allocate the common symbols from one list.
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template<int size>
|
|
void
|
|
do_allocate_commons_list(Layout*, Commons_section_type, Commons_type*,
|
|
Mapfile*);
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|
|
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// Implement detect_odr_violations.
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template<int size, bool big_endian>
|
|
void
|
|
sized_detect_odr_violations() const;
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|
|
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// Finalize symbols specialized for size.
|
|
template<int size>
|
|
off_t
|
|
sized_finalize(off_t, Stringpool*, unsigned int*);
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|
|
|
// Finalize a symbol. Return whether it should be added to the
|
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// symbol table.
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|
template<int size>
|
|
bool
|
|
sized_finalize_symbol(Symbol*);
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|
|
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// Add a symbol the final symtab by setting its index.
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|
template<int size>
|
|
void
|
|
add_to_final_symtab(Symbol*, Stringpool*, unsigned int* pindex, off_t* poff);
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|
|
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// Write globals specialized for size and endianness.
|
|
template<int size, bool big_endian>
|
|
void
|
|
sized_write_globals(const Stringpool*, const Stringpool*,
|
|
Output_symtab_xindex*, Output_symtab_xindex*,
|
|
Output_file*) const;
|
|
|
|
// Write out a symbol to P.
|
|
template<int size, bool big_endian>
|
|
void
|
|
sized_write_symbol(Sized_symbol<size>*,
|
|
typename elfcpp::Elf_types<size>::Elf_Addr value,
|
|
unsigned int shndx,
|
|
const Stringpool*, unsigned char* p) const;
|
|
|
|
// Possibly warn about an undefined symbol from a dynamic object.
|
|
void
|
|
warn_about_undefined_dynobj_symbol(Symbol*) const;
|
|
|
|
// Write out a section symbol, specialized for size and endianness.
|
|
template<int size, bool big_endian>
|
|
void
|
|
sized_write_section_symbol(const Output_section*, Output_symtab_xindex*,
|
|
Output_file*, off_t) const;
|
|
|
|
// The type of the list of symbols which have been forced local.
|
|
typedef std::vector<Symbol*> Forced_locals;
|
|
|
|
// A map from symbols with COPY relocs to the dynamic objects where
|
|
// they are defined.
|
|
typedef Unordered_map<const Symbol*, Dynobj*> Copied_symbol_dynobjs;
|
|
|
|
// A map from symbol name (as a pointer into the namepool) to all
|
|
// the locations the symbols is (weakly) defined (and certain other
|
|
// conditions are met). This map will be used later to detect
|
|
// possible One Definition Rule (ODR) violations.
|
|
struct Symbol_location
|
|
{
|
|
Object* object; // Object where the symbol is defined.
|
|
unsigned int shndx; // Section-in-object where the symbol is defined.
|
|
off_t offset; // Offset-in-section where the symbol is defined.
|
|
bool operator==(const Symbol_location& that) const
|
|
{
|
|
return (this->object == that.object
|
|
&& this->shndx == that.shndx
|
|
&& this->offset == that.offset);
|
|
}
|
|
};
|
|
|
|
struct Symbol_location_hash
|
|
{
|
|
size_t operator()(const Symbol_location& loc) const
|
|
{ return reinterpret_cast<uintptr_t>(loc.object) ^ loc.offset ^ loc.shndx; }
|
|
};
|
|
|
|
typedef Unordered_map<const char*,
|
|
Unordered_set<Symbol_location, Symbol_location_hash> >
|
|
Odr_map;
|
|
|
|
// We increment this every time we see a new undefined symbol, for
|
|
// use in archive groups.
|
|
int saw_undefined_;
|
|
// The index of the first global symbol in the output file.
|
|
unsigned int first_global_index_;
|
|
// The file offset within the output symtab section where we should
|
|
// write the table.
|
|
off_t offset_;
|
|
// The number of global symbols we want to write out.
|
|
unsigned int output_count_;
|
|
// The file offset of the global dynamic symbols, or 0 if none.
|
|
off_t dynamic_offset_;
|
|
// The index of the first global dynamic symbol.
|
|
unsigned int first_dynamic_global_index_;
|
|
// The number of global dynamic symbols, or 0 if none.
|
|
unsigned int dynamic_count_;
|
|
// The symbol hash table.
|
|
Symbol_table_type table_;
|
|
// A pool of symbol names. This is used for all global symbols.
|
|
// Entries in the hash table point into this pool.
|
|
Stringpool namepool_;
|
|
// Forwarding symbols.
|
|
Unordered_map<const Symbol*, Symbol*> forwarders_;
|
|
// Weak aliases. A symbol in this list points to the next alias.
|
|
// The aliases point to each other in a circular list.
|
|
Unordered_map<Symbol*, Symbol*> weak_aliases_;
|
|
// We don't expect there to be very many common symbols, so we keep
|
|
// a list of them. When we find a common symbol we add it to this
|
|
// list. It is possible that by the time we process the list the
|
|
// symbol is no longer a common symbol. It may also have become a
|
|
// forwarder.
|
|
Commons_type commons_;
|
|
// This is like the commons_ field, except that it holds TLS common
|
|
// symbols.
|
|
Commons_type tls_commons_;
|
|
// This is for small common symbols.
|
|
Commons_type small_commons_;
|
|
// This is for large common symbols.
|
|
Commons_type large_commons_;
|
|
// A list of symbols which have been forced to be local. We don't
|
|
// expect there to be very many of them, so we keep a list of them
|
|
// rather than walking the whole table to find them.
|
|
Forced_locals forced_locals_;
|
|
// Manage symbol warnings.
|
|
Warnings warnings_;
|
|
// Manage potential One Definition Rule (ODR) violations.
|
|
Odr_map candidate_odr_violations_;
|
|
|
|
// When we emit a COPY reloc for a symbol, we define it in an
|
|
// Output_data. When it's time to emit version information for it,
|
|
// we need to know the dynamic object in which we found the original
|
|
// definition. This maps symbols with COPY relocs to the dynamic
|
|
// object where they were defined.
|
|
Copied_symbol_dynobjs copied_symbol_dynobjs_;
|
|
// Information parsed from the version script, if any.
|
|
const Version_script_info& version_script_;
|
|
Garbage_collection* gc_;
|
|
Icf* icf_;
|
|
};
|
|
|
|
// We inline get_sized_symbol for efficiency.
|
|
|
|
template<int size>
|
|
Sized_symbol<size>*
|
|
Symbol_table::get_sized_symbol(Symbol* sym) const
|
|
{
|
|
gold_assert(size == parameters->target().get_size());
|
|
return static_cast<Sized_symbol<size>*>(sym);
|
|
}
|
|
|
|
template<int size>
|
|
const Sized_symbol<size>*
|
|
Symbol_table::get_sized_symbol(const Symbol* sym) const
|
|
{
|
|
gold_assert(size == parameters->target().get_size());
|
|
return static_cast<const Sized_symbol<size>*>(sym);
|
|
}
|
|
|
|
} // End namespace gold.
|
|
|
|
#endif // !defined(GOLD_SYMTAB_H)
|