518 lines
14 KiB
C++
518 lines
14 KiB
C++
// dynobj.h -- dynamic object support for gold -*- C++ -*-
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// Copyright 2006, 2007 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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#ifndef GOLD_DYNOBJ_H
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#define GOLD_DYNOBJ_H
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#include <vector>
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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 General_options;
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// A dynamic object (ET_DYN). This is an abstract base class itself.
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// The implementations is the template class Sized_dynobj.
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class Dynobj : public Object
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{
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public:
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Dynobj(const std::string& name, Input_file* input_file, off_t offset = 0)
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: Object(name, input_file, true, offset), soname_()
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{ }
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// Return the name to use in a DT_NEEDED entry for this object.
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const char*
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soname() const;
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// Compute the ELF hash code for a string.
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static uint32_t
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elf_hash(const char*);
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// Create a standard ELF hash table, setting *PPHASH and *PHASHLEN.
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// DYNSYMS is the global dynamic symbols. LOCAL_DYNSYM_COUNT is the
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// number of local dynamic symbols, which is the index of the first
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// dynamic gobal symbol.
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static void
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create_elf_hash_table(const std::vector<Symbol*>& dynsyms,
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unsigned int local_dynsym_count,
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unsigned char** pphash,
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unsigned int* phashlen);
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// Create a GNU hash table, setting *PPHASH and *PHASHLEN. DYNSYMS
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// is the global dynamic symbols. LOCAL_DYNSYM_COUNT is the number
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// of local dynamic symbols, which is the index of the first dynamic
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// gobal symbol.
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static void
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create_gnu_hash_table(const std::vector<Symbol*>& dynsyms,
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unsigned int local_dynsym_count,
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unsigned char** pphash, unsigned int* phashlen);
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protected:
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// Set the DT_SONAME string.
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void
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set_soname_string(const char* s)
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{ this->soname_.assign(s); }
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private:
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// Compute the GNU hash code for a string.
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static uint32_t
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gnu_hash(const char*);
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// Compute the number of hash buckets to use.
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static unsigned int
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compute_bucket_count(const std::vector<uint32_t>& hashcodes,
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bool for_gnu_hash_table);
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// Sized version of create_elf_hash_table.
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template<bool big_endian>
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static void
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sized_create_elf_hash_table(const std::vector<uint32_t>& bucket,
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const std::vector<uint32_t>& chain,
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unsigned char* phash,
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unsigned int hashlen);
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// Sized version of create_gnu_hash_table.
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template<int size, bool big_endian>
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static void
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sized_create_gnu_hash_table(const std::vector<Symbol*>& hashed_dynsyms,
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const std::vector<uint32_t>& dynsym_hashvals,
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unsigned int unhashed_dynsym_count,
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unsigned char** pphash,
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unsigned int* phashlen);
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// The DT_SONAME name, if any.
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std::string soname_;
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};
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// A dynamic object, size and endian specific version.
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template<int size, bool big_endian>
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class Sized_dynobj : public Dynobj
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{
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public:
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Sized_dynobj(const std::string& name, Input_file* input_file, off_t offset,
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const typename elfcpp::Ehdr<size, big_endian>&);
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// Set up the object file based on the ELF header.
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void
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setup(const typename elfcpp::Ehdr<size, big_endian>&);
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// Read the symbols.
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void
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do_read_symbols(Read_symbols_data*);
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// Lay out the input sections.
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void
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do_layout(Symbol_table*, Layout*, Read_symbols_data*);
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// Add the symbols to the symbol table.
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void
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do_add_symbols(Symbol_table*, Read_symbols_data*);
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// Get the name of a section.
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std::string
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do_section_name(unsigned int shndx)
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{ return this->elf_file_.section_name(shndx); }
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// Return a view of the contents of a section. Set *PLEN to the
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// size.
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Object::Location
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do_section_contents(unsigned int shndx)
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{ return this->elf_file_.section_contents(shndx); }
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// Return section flags.
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uint64_t
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do_section_flags(unsigned int shndx)
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{ return this->elf_file_.section_flags(shndx); }
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private:
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// For convenience.
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typedef Sized_dynobj<size, big_endian> This;
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static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
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static const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
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static const int dyn_size = elfcpp::Elf_sizes<size>::dyn_size;
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typedef elfcpp::Shdr<size, big_endian> Shdr;
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typedef elfcpp::Dyn<size, big_endian> Dyn;
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// Find the dynamic symbol table and the version sections, given the
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// section headers.
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void
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find_dynsym_sections(const unsigned char* pshdrs,
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unsigned int* pdynshm_shndx,
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unsigned int* pversym_shndx,
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unsigned int* pverdef_shndx,
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unsigned int* pverneed_shndx,
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unsigned int* pdynamic_shndx);
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// Read the dynamic symbol section SHNDX.
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void
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read_dynsym_section(const unsigned char* pshdrs, unsigned int shndx,
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elfcpp::SHT type, unsigned int link,
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File_view** view, off_t* view_size,
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unsigned int* view_info);
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// Set the SONAME from the SHT_DYNAMIC section at DYNAMIC_SHNDX.
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// The STRTAB parameters may have the relevant string table.
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void
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set_soname(const unsigned char* pshdrs, unsigned int dynamic_shndx,
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unsigned int strtab_shndx, const unsigned char* strtabu,
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off_t strtab_size);
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// Mapping from version number to version name.
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typedef std::vector<const char*> Version_map;
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// Create the version map.
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void
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make_version_map(Read_symbols_data* sd, Version_map*) const;
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// Add version definitions to the version map.
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void
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make_verdef_map(Read_symbols_data* sd, Version_map*) const;
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// Add version references to the version map.
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void
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make_verneed_map(Read_symbols_data* sd, Version_map*) const;
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// Add an entry to the version map.
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void
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set_version_map(Version_map*, unsigned int ndx, const char* name) const;
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// General access to the ELF file.
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elfcpp::Elf_file<size, big_endian, Object> elf_file_;
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};
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// A base class for Verdef and Verneed_version which just handles the
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// version index which will be stored in the SHT_GNU_versym section.
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class Version_base
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{
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public:
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Version_base()
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: index_(-1U)
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{ }
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virtual
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~Version_base()
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{ }
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// Return the version index.
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unsigned int
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index() const
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{
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gold_assert(this->index_ != -1U);
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return this->index_;
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}
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// Set the version index.
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void
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set_index(unsigned int index)
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{
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gold_assert(this->index_ == -1U);
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this->index_ = index;
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}
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// Clear the weak flag in a version definition.
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virtual void
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clear_weak() = 0;
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private:
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Version_base(const Version_base&);
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Version_base& operator=(const Version_base&);
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// The index of the version definition or reference.
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unsigned int index_;
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};
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// This class handles a version being defined in the file we are
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// generating.
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class Verdef : public Version_base
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{
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public:
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Verdef(const char* name, bool is_base, bool is_weak, bool is_symbol_created)
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: name_(name), deps_(), is_base_(is_base), is_weak_(is_weak),
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is_symbol_created_(is_symbol_created)
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{ }
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// Return the version 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 number of dependencies.
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unsigned int
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count_dependencies() const
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{ return this->deps_.size(); }
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// Add a dependency to this version. The NAME should be
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// canonicalized in the dynamic Stringpool.
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void
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add_dependency(const char* name)
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{ this->deps_.push_back(name); }
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// Return whether this definition is weak.
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bool
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is_weak() const
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{ return this->is_weak_; }
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// Clear the weak flag.
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void
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clear_weak()
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{ this->is_weak_ = false; }
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// Return whether a version symbol has been created for this
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// definition.
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bool
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is_symbol_created() const
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{ return this->is_symbol_created_; }
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// Write contents to buffer.
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template<int size, bool big_endian>
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unsigned char*
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write(const Stringpool*, bool is_last, unsigned char*
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ACCEPT_SIZE_ENDIAN) const;
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private:
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Verdef(const Verdef&);
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Verdef& operator=(const Verdef&);
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// The type of the list of version dependencies. Each dependency
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// should be canonicalized in the dynamic Stringpool.
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typedef std::vector<const char*> Deps;
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// The name of this version. This should be canonicalized in the
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// dynamic Stringpool.
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const char* name_;
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// A list of other versions which this version depends upon.
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Deps deps_;
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// Whether this is the base version.
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bool is_base_;
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// Whether this version is weak.
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bool is_weak_;
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// Whether a version symbol has been created.
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bool is_symbol_created_;
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};
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// A referened version. This will be associated with a filename by
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// Verneed.
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class Verneed_version : public Version_base
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{
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public:
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Verneed_version(const char* version)
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: version_(version)
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{ }
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// Return the version name.
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const char*
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version() const
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{ return this->version_; }
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// Clear the weak flag. This is invalid for a reference.
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void
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clear_weak()
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{ gold_unreachable(); }
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private:
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Verneed_version(const Verneed_version&);
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Verneed_version& operator=(const Verneed_version&);
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const char* version_;
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};
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// Version references in a single dynamic object.
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class Verneed
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{
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public:
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Verneed(const char* filename)
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: filename_(filename), need_versions_()
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{ }
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~Verneed();
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// Return the file name.
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const char*
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filename() const
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{ return this->filename_; }
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// Return the number of versions.
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unsigned int
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count_versions() const
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{ return this->need_versions_.size(); }
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// Add a version name. The name should be canonicalized in the
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// dynamic Stringpool. If the name is already present, this does
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// nothing.
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Verneed_version*
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add_name(const char* name);
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// Set the version indexes, starting at INDEX. Return the updated
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// INDEX.
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unsigned int
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finalize(unsigned int index);
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// Write contents to buffer.
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template<int size, bool big_endian>
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unsigned char*
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write(const Stringpool*, bool is_last, unsigned char*
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ACCEPT_SIZE_ENDIAN) const;
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private:
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Verneed(const Verneed&);
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Verneed& operator=(const Verneed&);
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// The type of the list of version names. Each name should be
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// canonicalized in the dynamic Stringpool.
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typedef std::vector<Verneed_version*> Need_versions;
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// The filename of the dynamic object. This should be
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// canonicalized in the dynamic Stringpool.
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const char* filename_;
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// The list of version names.
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Need_versions need_versions_;
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};
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// This class handles version definitions and references which go into
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// the output file.
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class Versions
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{
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public:
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Versions()
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: defs_(), needs_(), version_table_(), is_finalized_(false)
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{ }
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~Versions();
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// SYM is going into the dynamic symbol table and has a version.
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// Record the appropriate version information.
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void
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record_version(const Symbol_table* symtab, Stringpool*, const Symbol* sym);
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// Set the version indexes. DYNSYM_INDEX is the index we should use
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// for the next dynamic symbol. We add new dynamic symbols to SYMS
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// and return an updated DYNSYM_INDEX.
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unsigned int
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finalize(const Target*, Symbol_table* symtab, unsigned int dynsym_index,
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std::vector<Symbol*>* syms);
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// Return whether there are any version definitions.
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bool
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any_defs() const
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{ return !this->defs_.empty(); }
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// Return whether there are any version references.
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bool
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any_needs() const
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{ return !this->needs_.empty(); }
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// Build an allocated buffer holding the contents of the symbol
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// version section (.gnu.version).
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template<int size, bool big_endian>
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void
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symbol_section_contents(const Symbol_table*, const Stringpool*,
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unsigned int local_symcount,
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const std::vector<Symbol*>& syms,
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unsigned char**, unsigned int*
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ACCEPT_SIZE_ENDIAN) const;
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// Build an allocated buffer holding the contents of the version
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// definition section (.gnu.version_d).
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template<int size, bool big_endian>
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void
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def_section_contents(const Stringpool*, unsigned char**,
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unsigned int* psize, unsigned int* pentries
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ACCEPT_SIZE_ENDIAN) const;
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// Build an allocated buffer holding the contents of the version
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// reference section (.gnu.version_r).
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template<int size, bool big_endian>
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void
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need_section_contents(const Stringpool*, unsigned char**,
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unsigned int* psize, unsigned int* pentries
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ACCEPT_SIZE_ENDIAN) const;
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private:
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// The type of the list of version definitions.
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typedef std::vector<Verdef*> Defs;
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// The type of the list of version references.
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typedef std::vector<Verneed*> Needs;
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// Handle a symbol SYM defined with version VERSION.
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void
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add_def(const Symbol* sym, const char* version, Stringpool::Key);
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// Add a reference to version NAME in file FILENAME.
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void
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add_need(Stringpool*, const char* filename, const char* name,
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Stringpool::Key);
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// Get the dynamic object to use for SYM.
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Dynobj*
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get_dynobj_for_sym(const Symbol_table*, const Symbol* sym) const;
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// Return the version index to use for SYM.
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unsigned int
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version_index(const Symbol_table*, const Stringpool*,
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const Symbol* sym) const;
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// We keep a hash table mapping canonicalized name/version pairs to
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// a version base.
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typedef std::pair<Stringpool::Key, Stringpool::Key> Key;
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struct Version_table_hash
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{
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size_t
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operator()(const Key& k) const
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{ return k.first + k.second; }
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};
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struct Version_table_eq
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{
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bool
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operator()(const Key& k1, const Key& k2) const
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{ return k1.first == k2.first && k1.second == k2.second; }
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};
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typedef Unordered_map<Key, Version_base*, Version_table_hash,
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Version_table_eq> Version_table;
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// The version definitions.
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Defs defs_;
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// The version references.
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Needs needs_;
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// The mapping from a canonicalized version/filename pair to a
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// version index. The filename may be NULL.
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Version_table version_table_;
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// Whether the version indexes have been set.
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bool is_finalized_;
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};
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} // End namespace gold.
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#endif // !defined(GOLD_DYNOBJ_H)
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