1145 lines
34 KiB
C++
1145 lines
34 KiB
C++
// object.h -- support for an object file for linking in 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_OBJECT_H
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#define GOLD_OBJECT_H
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#include <string>
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#include <vector>
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#include "elfcpp.h"
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#include "elfcpp_file.h"
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#include "fileread.h"
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#include "target.h"
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namespace gold
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{
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class General_options;
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class Layout;
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class Output_section;
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class Output_file;
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class Dynobj;
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class Object_merge_map;
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template<typename Stringpool_char>
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class Stringpool_template;
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// Data to pass from read_symbols() to add_symbols().
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struct Read_symbols_data
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{
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// Section headers.
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File_view* section_headers;
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// Section names.
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File_view* section_names;
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// Size of section name data in bytes.
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off_t section_names_size;
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// Symbol data.
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File_view* symbols;
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// Size of symbol data in bytes.
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off_t symbols_size;
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// Offset of external symbols within symbol data. This structure
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// sometimes contains only external symbols, in which case this will
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// be zero. Sometimes it contains all symbols.
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off_t external_symbols_offset;
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// Symbol names.
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File_view* symbol_names;
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// Size of symbol name data in bytes.
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off_t symbol_names_size;
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// Version information. This is only used on dynamic objects.
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// Version symbol data (from SHT_GNU_versym section).
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File_view* versym;
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off_t versym_size;
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// Version definition data (from SHT_GNU_verdef section).
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File_view* verdef;
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off_t verdef_size;
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unsigned int verdef_info;
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// Needed version data (from SHT_GNU_verneed section).
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File_view* verneed;
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off_t verneed_size;
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unsigned int verneed_info;
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};
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// Information used to print error messages.
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struct Symbol_location_info
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{
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std::string source_file;
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std::string enclosing_symbol_name;
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int line_number;
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};
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// Data about a single relocation section. This is read in
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// read_relocs and processed in scan_relocs.
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struct Section_relocs
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{
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// Index of reloc section.
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unsigned int reloc_shndx;
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// Index of section that relocs apply to.
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unsigned int data_shndx;
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// Contents of reloc section.
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File_view* contents;
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// Reloc section type.
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unsigned int sh_type;
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// Number of reloc entries.
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size_t reloc_count;
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// Output section.
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Output_section* output_section;
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// Whether this section has special handling for offsets.
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bool needs_special_offset_handling;
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};
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// Relocations in an object file. This is read in read_relocs and
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// processed in scan_relocs.
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struct Read_relocs_data
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{
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typedef std::vector<Section_relocs> Relocs_list;
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// The relocations.
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Relocs_list relocs;
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// The local symbols.
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File_view* local_symbols;
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};
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// Object is an abstract base class which represents either a 32-bit
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// or a 64-bit input object. This can be a regular object file
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// (ET_REL) or a shared object (ET_DYN).
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class Object
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{
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public:
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// NAME is the name of the object as we would report it to the user
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// (e.g., libfoo.a(bar.o) if this is in an archive. INPUT_FILE is
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// used to read the file. OFFSET is the offset within the input
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// file--0 for a .o or .so file, something else for a .a file.
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Object(const std::string& name, Input_file* input_file, bool is_dynamic,
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off_t offset = 0)
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: name_(name), input_file_(input_file), offset_(offset), shnum_(-1U),
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is_dynamic_(is_dynamic), target_(NULL)
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{ }
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virtual ~Object()
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{ }
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// Return the name of the object as we would report it to the tuser.
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const std::string&
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name() const
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{ return this->name_; }
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// Get the offset into the file.
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off_t
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offset() const
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{ return this->offset_; }
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// Return whether this is a dynamic object.
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bool
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is_dynamic() const
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{ return this->is_dynamic_; }
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// Return the target structure associated with this object.
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Target*
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target() const
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{ return this->target_; }
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// Lock the underlying file.
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void
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lock()
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{ this->input_file_->file().lock(); }
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// Unlock the underlying file.
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void
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unlock()
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{ this->input_file_->file().unlock(); }
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// Return whether the underlying file is locked.
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bool
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is_locked() const
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{ return this->input_file_->file().is_locked(); }
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// Return the sized target structure associated with this object.
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// This is like the target method but it returns a pointer of
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// appropriate checked type.
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template<int size, bool big_endian>
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Sized_target<size, big_endian>*
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sized_target(ACCEPT_SIZE_ENDIAN_ONLY);
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// Get the number of sections.
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unsigned int
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shnum() const
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{ return this->shnum_; }
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// Return a view of the contents of a section. Set *PLEN to the
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// size. CACHE is a hint as in File_read::get_view.
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const unsigned char*
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section_contents(unsigned int shndx, off_t* plen, bool cache);
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// Return the name of a section given a section index. This is only
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// used for error messages.
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std::string
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section_name(unsigned int shndx)
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{ return this->do_section_name(shndx); }
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// Return the section flags given a section index.
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uint64_t
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section_flags(unsigned int shndx)
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{ return this->do_section_flags(shndx); }
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// Return the section type given a section index.
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unsigned int
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section_type(unsigned int shndx)
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{ return this->do_section_type(shndx); }
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// Return the section link field given a section index.
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unsigned int
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section_link(unsigned int shndx)
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{ return this->do_section_link(shndx); }
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// Return the section info field given a section index.
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unsigned int
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section_info(unsigned int shndx)
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{ return this->do_section_info(shndx); }
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// Read the symbol information.
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void
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read_symbols(Read_symbols_data* sd)
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{ return this->do_read_symbols(sd); }
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// Pass sections which should be included in the link to the Layout
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// object, and record where the sections go in the output file.
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void
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layout(Symbol_table* symtab, Layout* layout, Read_symbols_data* sd)
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{ this->do_layout(symtab, layout, sd); }
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// Add symbol information to the global symbol table.
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void
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add_symbols(Symbol_table* symtab, Read_symbols_data* sd)
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{ this->do_add_symbols(symtab, sd); }
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// Functions and types for the elfcpp::Elf_file interface. This
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// permit us to use Object as the File template parameter for
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// elfcpp::Elf_file.
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// The View class is returned by view. It must support a single
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// method, data(). This is trivial, because get_view does what we
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// need.
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class View
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{
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public:
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View(const unsigned char* p)
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: p_(p)
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{ }
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const unsigned char*
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data() const
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{ return this->p_; }
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private:
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const unsigned char* p_;
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};
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// Return a View.
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View
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view(off_t file_offset, off_t data_size)
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{ return View(this->get_view(file_offset, data_size, true)); }
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// Report an error.
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void
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error(const char* format, ...) const ATTRIBUTE_PRINTF_2;
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// A location in the file.
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struct Location
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{
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off_t file_offset;
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off_t data_size;
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Location(off_t fo, off_t ds)
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: file_offset(fo), data_size(ds)
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{ }
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};
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// Get a View given a Location.
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View view(Location loc)
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{ return View(this->get_view(loc.file_offset, loc.data_size, true)); }
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protected:
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// Read the symbols--implemented by child class.
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virtual void
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do_read_symbols(Read_symbols_data*) = 0;
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// Lay out sections--implemented by child class.
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virtual void
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do_layout(Symbol_table*, Layout*, Read_symbols_data*) = 0;
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// Add symbol information to the global symbol table--implemented by
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// child class.
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virtual void
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do_add_symbols(Symbol_table*, Read_symbols_data*) = 0;
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// Return the location of the contents of a section. Implemented by
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// child class.
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virtual Location
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do_section_contents(unsigned int shndx) = 0;
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// Get the name of a section--implemented by child class.
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virtual std::string
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do_section_name(unsigned int shndx) = 0;
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// Get section flags--implemented by child class.
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virtual uint64_t
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do_section_flags(unsigned int shndx) = 0;
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// Get section type--implemented by child class.
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virtual unsigned int
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do_section_type(unsigned int shndx) = 0;
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// Get section link field--implemented by child class.
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virtual unsigned int
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do_section_link(unsigned int shndx) = 0;
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// Get section info field--implemented by child class.
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virtual unsigned int
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do_section_info(unsigned int shndx) = 0;
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// Get the file.
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Input_file*
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input_file() const
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{ return this->input_file_; }
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// Get a view into the underlying file.
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const unsigned char*
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get_view(off_t start, off_t size, bool cache)
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{
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return this->input_file_->file().get_view(start + this->offset_, size,
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cache);
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}
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// Get a lasting view into the underlying file.
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File_view*
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get_lasting_view(off_t start, off_t size, bool cache)
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{
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return this->input_file_->file().get_lasting_view(start + this->offset_,
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size, cache);
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}
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// Read data from the underlying file.
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void
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read(off_t start, off_t size, void* p)
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{ this->input_file_->file().read(start + this->offset_, size, p); }
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// Set the target.
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void
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set_target(int machine, int size, bool big_endian, int osabi,
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int abiversion);
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// Set the number of sections.
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void
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set_shnum(int shnum)
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{ this->shnum_ = shnum; }
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// Functions used by both Sized_relobj and Sized_dynobj.
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// Read the section data into a Read_symbols_data object.
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template<int size, bool big_endian>
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void
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read_section_data(elfcpp::Elf_file<size, big_endian, Object>*,
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Read_symbols_data*);
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// If NAME is the name of a special .gnu.warning section, arrange
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// for the warning to be issued. SHNDX is the section index.
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// Return whether it is a warning section.
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bool
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handle_gnu_warning_section(const char* name, unsigned int shndx,
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Symbol_table*);
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private:
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// This class may not be copied.
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Object(const Object&);
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Object& operator=(const Object&);
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// Name of object as printed to user.
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std::string name_;
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// For reading the file.
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Input_file* input_file_;
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// Offset within the file--0 for an object file, non-0 for an
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// archive.
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off_t offset_;
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// Number of input sections.
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unsigned int shnum_;
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// Whether this is a dynamic object.
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bool is_dynamic_;
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// Target functions--may be NULL if the target is not known.
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Target* target_;
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};
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// Implement sized_target inline for efficiency. This approach breaks
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// static type checking, but is made safe using asserts.
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template<int size, bool big_endian>
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inline Sized_target<size, big_endian>*
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Object::sized_target(ACCEPT_SIZE_ENDIAN_ONLY)
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{
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gold_assert(this->target_->get_size() == size);
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gold_assert(this->target_->is_big_endian() ? big_endian : !big_endian);
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return static_cast<Sized_target<size, big_endian>*>(this->target_);
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}
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// A regular object (ET_REL). This is an abstract base class itself.
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// The implementation is the template class Sized_relobj.
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class Relobj : public Object
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{
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public:
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Relobj(const std::string& name, Input_file* input_file, off_t offset = 0)
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: Object(name, input_file, false, offset),
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map_to_output_(),
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object_merge_map_(NULL),
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relocs_must_follow_section_writes_(false)
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{ }
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// Read the relocs.
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void
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read_relocs(Read_relocs_data* rd)
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{ return this->do_read_relocs(rd); }
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// Scan the relocs and adjust the symbol table.
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void
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scan_relocs(const General_options& options, Symbol_table* symtab,
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Layout* layout, Read_relocs_data* rd)
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{ return this->do_scan_relocs(options, symtab, layout, rd); }
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// Initial local symbol processing: set the offset where local
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// symbol information will be stored; add local symbol names to
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// *POOL; return the new local symbol index.
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unsigned int
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finalize_local_symbols(unsigned int index, off_t off,
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Stringpool_template<char>* pool)
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{ return this->do_finalize_local_symbols(index, off, pool); }
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// Relocate the input sections and write out the local symbols.
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void
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relocate(const General_options& options, const Symbol_table* symtab,
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const Layout* layout, Output_file* of)
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{ return this->do_relocate(options, symtab, layout, of); }
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// Return whether an input section is being included in the link.
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bool
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is_section_included(unsigned int shndx) const
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{
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gold_assert(shndx < this->map_to_output_.size());
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return this->map_to_output_[shndx].output_section != NULL;
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}
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// Return whether an input section requires special
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// handling--whether it is not simply mapped from the input file to
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// the output file.
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bool
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is_section_specially_mapped(unsigned int shndx) const
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{
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gold_assert(shndx < this->map_to_output_.size());
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return (this->map_to_output_[shndx].output_section != NULL
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&& this->map_to_output_[shndx].offset == -1);
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}
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// Given a section index, return the corresponding Output_section
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// (which will be NULL if the section is not included in the link)
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// and set *POFF to the offset within that section. *POFF will be
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// set to -1 if the section requires special handling.
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inline Output_section*
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output_section(unsigned int shndx, off_t* poff) const;
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// Set the offset of an input section within its output section.
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void
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set_section_offset(unsigned int shndx, off_t off)
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{
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gold_assert(shndx < this->map_to_output_.size());
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this->map_to_output_[shndx].offset = off;
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}
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// Return true if we need to wait for output sections to be written
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// before we can apply relocations. This is true if the object has
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// any relocations for sections which require special handling, such
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// as the exception frame section.
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bool
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relocs_must_follow_section_writes()
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{ return this->relocs_must_follow_section_writes_; }
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// Return the object merge map.
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Object_merge_map*
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merge_map() const
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{ return this->object_merge_map_; }
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// Set the object merge map.
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void
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set_merge_map(Object_merge_map* object_merge_map)
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{
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gold_assert(this->object_merge_map_ == NULL);
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this->object_merge_map_ = object_merge_map;
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}
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protected:
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// What we need to know to map an input section to an output
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// section. We keep an array of these, one for each input section,
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// indexed by the input section number.
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struct Map_to_output
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{
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// The output section. This is NULL if the input section is to be
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// discarded.
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Output_section* output_section;
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// The offset within the output section. This is -1 if the
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// section requires special handling.
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off_t offset;
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};
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// Read the relocs--implemented by child class.
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virtual void
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do_read_relocs(Read_relocs_data*) = 0;
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// Scan the relocs--implemented by child class.
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virtual void
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do_scan_relocs(const General_options&, Symbol_table*, Layout*,
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Read_relocs_data*) = 0;
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// Finalize local symbols--implemented by child class.
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virtual unsigned int
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do_finalize_local_symbols(unsigned int, off_t,
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Stringpool_template<char>*) = 0;
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// Relocate the input sections and write out the local
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// symbols--implemented by child class.
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virtual void
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do_relocate(const General_options& options, const Symbol_table* symtab,
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const Layout*, Output_file* of) = 0;
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// Return the vector mapping input sections to output sections.
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std::vector<Map_to_output>&
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map_to_output()
|
|
{ return this->map_to_output_; }
|
|
|
|
const std::vector<Map_to_output>&
|
|
map_to_output() const
|
|
{ return this->map_to_output_; }
|
|
|
|
// Record that we must wait for the output sections to be written
|
|
// before applying relocations.
|
|
void
|
|
set_relocs_must_follow_section_writes()
|
|
{ this->relocs_must_follow_section_writes_ = true; }
|
|
|
|
private:
|
|
// Mapping from input sections to output section.
|
|
std::vector<Map_to_output> map_to_output_;
|
|
// Mappings for merge sections. This is managed by the code in the
|
|
// Merge_map class.
|
|
Object_merge_map* object_merge_map_;
|
|
// Whether we need to wait for output sections to be written before
|
|
// we can apply relocations.
|
|
bool relocs_must_follow_section_writes_;
|
|
};
|
|
|
|
// Implement Object::output_section inline for efficiency.
|
|
inline Output_section*
|
|
Relobj::output_section(unsigned int shndx, off_t* poff) const
|
|
{
|
|
gold_assert(shndx < this->map_to_output_.size());
|
|
const Map_to_output& mo(this->map_to_output_[shndx]);
|
|
*poff = mo.offset;
|
|
return mo.output_section;
|
|
}
|
|
|
|
// This POD class is holds the value of a symbol. This is used for
|
|
// local symbols, and for all symbols during relocation processing.
|
|
// For special sections, such as SHF_MERGE sections, this calls a
|
|
// function to get the final symbol value.
|
|
|
|
template<int size>
|
|
class Symbol_value
|
|
{
|
|
public:
|
|
typedef typename elfcpp::Elf_types<size>::Elf_Addr Value;
|
|
|
|
Symbol_value()
|
|
: output_symtab_index_(0), input_shndx_(0), is_section_symbol_(false),
|
|
needs_output_address_(false), value_(0)
|
|
{ }
|
|
|
|
// Get the value of this symbol. OBJECT is the object in which this
|
|
// symbol is defined, and ADDEND is an addend to add to the value.
|
|
template<bool big_endian>
|
|
Value
|
|
value(const Sized_relobj<size, big_endian>* object, Value addend) const
|
|
{
|
|
if (!this->needs_output_address_)
|
|
return this->value_ + addend;
|
|
return object->local_value(this->input_shndx_, this->value_,
|
|
this->is_section_symbol_, addend);
|
|
}
|
|
|
|
// Set the value of this symbol in the output symbol table.
|
|
void
|
|
set_output_value(Value value)
|
|
{
|
|
this->value_ = value;
|
|
this->needs_output_address_ = false;
|
|
}
|
|
|
|
// If this symbol is mapped to an output section which requires
|
|
// special handling to determine the output value, we store the
|
|
// value of the symbol in the input file. This is used for
|
|
// SHF_MERGE sections.
|
|
void
|
|
set_input_value(Value value)
|
|
{
|
|
this->value_ = value;
|
|
this->needs_output_address_ = true;
|
|
}
|
|
|
|
// Return whether this symbol should go into the output symbol
|
|
// table.
|
|
bool
|
|
needs_output_symtab_entry() const
|
|
{
|
|
gold_assert(this->output_symtab_index_ != 0);
|
|
return this->output_symtab_index_ != -1U;
|
|
}
|
|
|
|
// Return the index in the output symbol table.
|
|
unsigned int
|
|
output_symtab_index() const
|
|
{
|
|
gold_assert(this->output_symtab_index_ != 0);
|
|
return this->output_symtab_index_;
|
|
}
|
|
|
|
// Set the index in the output symbol table.
|
|
void
|
|
set_output_symtab_index(unsigned int i)
|
|
{
|
|
gold_assert(this->output_symtab_index_ == 0);
|
|
this->output_symtab_index_ = i;
|
|
}
|
|
|
|
// Record that this symbol should not go into the output symbol
|
|
// table.
|
|
void
|
|
set_no_output_symtab_entry()
|
|
{
|
|
gold_assert(this->output_symtab_index_ == 0);
|
|
this->output_symtab_index_ = -1U;
|
|
}
|
|
|
|
// Set the index of the input section in the input file.
|
|
void
|
|
set_input_shndx(unsigned int i)
|
|
{
|
|
this->input_shndx_ = i;
|
|
gold_assert(this->input_shndx_ == i);
|
|
}
|
|
|
|
// Record that this is a section symbol.
|
|
void
|
|
set_is_section_symbol()
|
|
{ this->is_section_symbol_ = true; }
|
|
|
|
private:
|
|
// The index of this local symbol in the output symbol table. This
|
|
// will be -1 if the symbol should not go into the symbol table.
|
|
unsigned int output_symtab_index_;
|
|
// The section index in the input file in which this symbol is
|
|
// defined.
|
|
unsigned int input_shndx_ : 30;
|
|
// Whether this is a STT_SECTION symbol.
|
|
bool is_section_symbol_ : 1;
|
|
// Whether getting the value of this symbol requires calling an
|
|
// Output_section method. For example, this will be true of a
|
|
// symbol in a SHF_MERGE section.
|
|
bool needs_output_address_ : 1;
|
|
// The value of the symbol. If !needs_output_address_, this is the
|
|
// value in the output file. If needs_output_address_, this is the
|
|
// value in the input file.
|
|
Value value_;
|
|
};
|
|
|
|
// A regular object file. This is size and endian specific.
|
|
|
|
template<int size, bool big_endian>
|
|
class Sized_relobj : public Relobj
|
|
{
|
|
public:
|
|
typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
|
|
typedef std::vector<Symbol*> Symbols;
|
|
typedef std::vector<Symbol_value<size> > Local_values;
|
|
|
|
Sized_relobj(const std::string& name, Input_file* input_file, off_t offset,
|
|
const typename elfcpp::Ehdr<size, big_endian>&);
|
|
|
|
~Sized_relobj();
|
|
|
|
// Set up the object file based on the ELF header.
|
|
void
|
|
setup(const typename elfcpp::Ehdr<size, big_endian>&);
|
|
|
|
// Return the number of local symbols.
|
|
unsigned int
|
|
local_symbol_count() const
|
|
{ return this->local_symbol_count_; }
|
|
|
|
// If SYM is the index of a global symbol in the object file's
|
|
// symbol table, return the Symbol object. Otherwise, return NULL.
|
|
Symbol*
|
|
global_symbol(unsigned int sym) const
|
|
{
|
|
if (sym >= this->local_symbol_count_)
|
|
{
|
|
gold_assert(sym - this->local_symbol_count_ < this->symbols_.size());
|
|
return this->symbols_[sym - this->local_symbol_count_];
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
// Return the section index of symbol SYM. Set *VALUE to its value
|
|
// in the object file. Note that for a symbol which is not defined
|
|
// in this object file, this will set *VALUE to 0 and return
|
|
// SHN_UNDEF; it will not return the final value of the symbol in
|
|
// the link.
|
|
unsigned int
|
|
symbol_section_and_value(unsigned int sym, Address* value);
|
|
|
|
// Return a pointer to the Symbol_value structure which holds the
|
|
// value of a local symbol.
|
|
const Symbol_value<size>*
|
|
local_symbol(unsigned int sym) const
|
|
{
|
|
gold_assert(sym < this->local_values_.size());
|
|
return &this->local_values_[sym];
|
|
}
|
|
|
|
// Return the index of local symbol SYM in the ordinary symbol
|
|
// table. A value of -1U means that the symbol is not being output.
|
|
unsigned int
|
|
symtab_index(unsigned int sym) const
|
|
{
|
|
gold_assert(sym < this->local_values_.size());
|
|
return this->local_values_[sym].output_symtab_index();
|
|
}
|
|
|
|
// Return the appropriate Sized_target structure.
|
|
Sized_target<size, big_endian>*
|
|
sized_target()
|
|
{
|
|
return this->Object::sized_target
|
|
SELECT_SIZE_ENDIAN_NAME(size, big_endian) (
|
|
SELECT_SIZE_ENDIAN_ONLY(size, big_endian));
|
|
}
|
|
|
|
// Return the value of the local symbol symndx.
|
|
Address
|
|
local_symbol_value(unsigned int symndx) const;
|
|
|
|
// Return the value of a local symbol defined in input section
|
|
// SHNDX, with value VALUE, adding addend ADDEND. IS_SECTION_SYMBOL
|
|
// indicates whether the symbol is a section symbol. This handles
|
|
// SHF_MERGE sections.
|
|
Address
|
|
local_value(unsigned int shndx, Address value, bool is_section_symbol,
|
|
Address addend) const;
|
|
|
|
// Return whether the local symbol SYMNDX has a GOT offset.
|
|
// For TLS symbols, the GOT entry will hold its tp-relative offset.
|
|
bool
|
|
local_has_got_offset(unsigned int symndx) const
|
|
{
|
|
return (this->local_got_offsets_.find(symndx)
|
|
!= this->local_got_offsets_.end());
|
|
}
|
|
|
|
// Return the GOT offset of the local symbol SYMNDX.
|
|
unsigned int
|
|
local_got_offset(unsigned int symndx) const
|
|
{
|
|
Local_got_offsets::const_iterator p =
|
|
this->local_got_offsets_.find(symndx);
|
|
gold_assert(p != this->local_got_offsets_.end());
|
|
return p->second;
|
|
}
|
|
|
|
// Set the GOT offset of the local symbol SYMNDX to GOT_OFFSET.
|
|
void
|
|
set_local_got_offset(unsigned int symndx, unsigned int got_offset)
|
|
{
|
|
std::pair<Local_got_offsets::iterator, bool> ins =
|
|
this->local_got_offsets_.insert(std::make_pair(symndx, got_offset));
|
|
gold_assert(ins.second);
|
|
}
|
|
|
|
// Return whether the local TLS symbol SYMNDX has a GOT offset.
|
|
// The GOT entry at this offset will contain a module index. If
|
|
// NEED_PAIR is true, a second entry immediately following the first
|
|
// will contain the dtv-relative offset.
|
|
bool
|
|
local_has_tls_got_offset(unsigned int symndx, bool need_pair) const
|
|
{
|
|
typename Local_tls_got_offsets::const_iterator p =
|
|
this->local_tls_got_offsets_.find(symndx);
|
|
if (p == this->local_tls_got_offsets_.end()
|
|
|| (need_pair && !p->second.have_pair_))
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
// Return the offset of the GOT entry for the local TLS symbol SYMNDX.
|
|
// If NEED_PAIR is true, we need the offset of a pair of GOT entries;
|
|
// otherwise we need the offset of the GOT entry for the module index.
|
|
unsigned int
|
|
local_tls_got_offset(unsigned int symndx, bool need_pair) const
|
|
{
|
|
typename Local_tls_got_offsets::const_iterator p =
|
|
this->local_tls_got_offsets_.find(symndx);
|
|
gold_assert(p != this->local_tls_got_offsets_.end());
|
|
gold_assert(!need_pair || p->second.have_pair_);
|
|
return p->second.got_offset_;
|
|
}
|
|
|
|
// Set the offset of the GOT entry for the local TLS symbol SYMNDX
|
|
// to GOT_OFFSET. If HAVE_PAIR is true, we have a pair of GOT entries;
|
|
// otherwise, we have just a single entry for the module index.
|
|
void
|
|
set_local_tls_got_offset(unsigned int symndx, unsigned int got_offset,
|
|
bool have_pair)
|
|
{
|
|
typename Local_tls_got_offsets::iterator p =
|
|
this->local_tls_got_offsets_.find(symndx);
|
|
if (p != this->local_tls_got_offsets_.end())
|
|
{
|
|
// An entry already existed for this symbol. This can happen
|
|
// if we see a relocation asking for the module index before
|
|
// a relocation asking for the pair. In that case, the original
|
|
// GOT entry will remain, but won't get used by any further
|
|
// relocations.
|
|
p->second.got_offset_ = got_offset;
|
|
gold_assert(have_pair);
|
|
p->second.have_pair_ = true;
|
|
}
|
|
else
|
|
{
|
|
std::pair<typename Local_tls_got_offsets::iterator, bool> ins =
|
|
this->local_tls_got_offsets_.insert(
|
|
std::make_pair(symndx, Tls_got_entry(got_offset, have_pair)));
|
|
gold_assert(ins.second);
|
|
}
|
|
}
|
|
|
|
// Return the name of the symbol that spans the given offset in the
|
|
// specified section in this object. This is used only for error
|
|
// messages and is not particularly efficient.
|
|
bool
|
|
get_symbol_location_info(unsigned int shndx, off_t offset,
|
|
Symbol_location_info* info);
|
|
|
|
// Read the symbols.
|
|
void
|
|
do_read_symbols(Read_symbols_data*);
|
|
|
|
// Lay out the input sections.
|
|
void
|
|
do_layout(Symbol_table*, Layout*, Read_symbols_data*);
|
|
|
|
// Add the symbols to the symbol table.
|
|
void
|
|
do_add_symbols(Symbol_table*, Read_symbols_data*);
|
|
|
|
// Read the relocs.
|
|
void
|
|
do_read_relocs(Read_relocs_data*);
|
|
|
|
// Scan the relocs and adjust the symbol table.
|
|
void
|
|
do_scan_relocs(const General_options&, Symbol_table*, Layout*,
|
|
Read_relocs_data*);
|
|
|
|
// Finalize the local symbols.
|
|
unsigned int
|
|
do_finalize_local_symbols(unsigned int, off_t,
|
|
Stringpool_template<char>*);
|
|
|
|
// Relocate the input sections and write out the local symbols.
|
|
void
|
|
do_relocate(const General_options& options, const Symbol_table* symtab,
|
|
const Layout*, Output_file* of);
|
|
|
|
// Get the name of a section.
|
|
std::string
|
|
do_section_name(unsigned int shndx)
|
|
{ return this->elf_file_.section_name(shndx); }
|
|
|
|
// Return the location of the contents of a section.
|
|
Object::Location
|
|
do_section_contents(unsigned int shndx)
|
|
{ return this->elf_file_.section_contents(shndx); }
|
|
|
|
// Return section flags.
|
|
uint64_t
|
|
do_section_flags(unsigned int shndx)
|
|
{ return this->elf_file_.section_flags(shndx); }
|
|
|
|
// Return section type.
|
|
unsigned int
|
|
do_section_type(unsigned int shndx)
|
|
{ return this->elf_file_.section_type(shndx); }
|
|
|
|
// Return the section link field.
|
|
unsigned int
|
|
do_section_link(unsigned int shndx)
|
|
{ return this->elf_file_.section_link(shndx); }
|
|
|
|
// Return the section info field.
|
|
unsigned int
|
|
do_section_info(unsigned int shndx)
|
|
{ return this->elf_file_.section_info(shndx); }
|
|
|
|
private:
|
|
// For convenience.
|
|
typedef Sized_relobj<size, big_endian> This;
|
|
static const int ehdr_size = elfcpp::Elf_sizes<size>::ehdr_size;
|
|
static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
|
|
static const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
|
|
typedef elfcpp::Shdr<size, big_endian> Shdr;
|
|
|
|
// Find the SHT_SYMTAB section, given the section headers.
|
|
void
|
|
find_symtab(const unsigned char* pshdrs);
|
|
|
|
// Return whether SHDR has the right flags for a GNU style exception
|
|
// frame section.
|
|
bool
|
|
check_eh_frame_flags(const elfcpp::Shdr<size, big_endian>* shdr) const;
|
|
|
|
// Return whether there is a section named .eh_frame which might be
|
|
// a GNU style exception frame section.
|
|
bool
|
|
find_eh_frame(const unsigned char* pshdrs, const char* names,
|
|
off_t names_size) const;
|
|
|
|
// Whether to include a section group in the link.
|
|
bool
|
|
include_section_group(Layout*, unsigned int,
|
|
const elfcpp::Shdr<size, big_endian>&,
|
|
std::vector<bool>*);
|
|
|
|
// Whether to include a linkonce section in the link.
|
|
bool
|
|
include_linkonce_section(Layout*, const char*,
|
|
const elfcpp::Shdr<size, big_endian>&);
|
|
|
|
// Views and sizes when relocating.
|
|
struct View_size
|
|
{
|
|
unsigned char* view;
|
|
typename elfcpp::Elf_types<size>::Elf_Addr address;
|
|
off_t offset;
|
|
off_t view_size;
|
|
bool is_input_output_view;
|
|
bool is_postprocessing_view;
|
|
};
|
|
|
|
typedef std::vector<View_size> Views;
|
|
|
|
// Write section data to the output file. Record the views and
|
|
// sizes in VIEWS for use when relocating.
|
|
void
|
|
write_sections(const unsigned char* pshdrs, Output_file*, Views*);
|
|
|
|
// Relocate the sections in the output file.
|
|
void
|
|
relocate_sections(const General_options& options, const Symbol_table*,
|
|
const Layout*, const unsigned char* pshdrs, Views*);
|
|
|
|
// Write out the local symbols.
|
|
void
|
|
write_local_symbols(Output_file*,
|
|
const Stringpool_template<char>*);
|
|
|
|
// The GOT offsets of local symbols. This map also stores GOT offsets
|
|
// for tp-relative offsets for TLS symbols.
|
|
typedef Unordered_map<unsigned int, unsigned int> Local_got_offsets;
|
|
|
|
// The TLS GOT offsets of local symbols. The map stores the offsets
|
|
// for either a single GOT entry that holds the module index of a TLS
|
|
// symbol, or a pair of GOT entries containing the module index and
|
|
// dtv-relative offset.
|
|
struct Tls_got_entry
|
|
{
|
|
Tls_got_entry(int got_offset, bool have_pair)
|
|
: got_offset_(got_offset),
|
|
have_pair_(have_pair)
|
|
{ }
|
|
int got_offset_;
|
|
bool have_pair_;
|
|
};
|
|
typedef Unordered_map<unsigned int, Tls_got_entry> Local_tls_got_offsets;
|
|
|
|
// General access to the ELF file.
|
|
elfcpp::Elf_file<size, big_endian, Object> elf_file_;
|
|
// Index of SHT_SYMTAB section.
|
|
unsigned int symtab_shndx_;
|
|
// The number of local symbols.
|
|
unsigned int local_symbol_count_;
|
|
// The number of local symbols which go into the output file.
|
|
unsigned int output_local_symbol_count_;
|
|
// The entries in the symbol table for the external symbols.
|
|
Symbols symbols_;
|
|
// File offset for local symbols.
|
|
off_t local_symbol_offset_;
|
|
// Values of local symbols.
|
|
Local_values local_values_;
|
|
// GOT offsets for local non-TLS symbols, and tp-relative offsets
|
|
// for TLS symbols, indexed by symbol number.
|
|
Local_got_offsets local_got_offsets_;
|
|
// GOT offsets for local TLS symbols, indexed by symbol number
|
|
// and GOT entry type.
|
|
Local_tls_got_offsets local_tls_got_offsets_;
|
|
// Whether this object has a GNU style .eh_frame section.
|
|
bool has_eh_frame_;
|
|
};
|
|
|
|
// A class to manage the list of all objects.
|
|
|
|
class Input_objects
|
|
{
|
|
public:
|
|
Input_objects()
|
|
: relobj_list_(), dynobj_list_(), target_(NULL), sonames_(),
|
|
system_library_directory_()
|
|
{ }
|
|
|
|
// The type of the list of input relocateable objects.
|
|
typedef std::vector<Relobj*> Relobj_list;
|
|
typedef Relobj_list::const_iterator Relobj_iterator;
|
|
|
|
// The type of the list of input dynamic objects.
|
|
typedef std::vector<Dynobj*> Dynobj_list;
|
|
typedef Dynobj_list::const_iterator Dynobj_iterator;
|
|
|
|
// Add an object to the list. Return true if all is well, or false
|
|
// if this object should be ignored.
|
|
bool
|
|
add_object(Object*);
|
|
|
|
// Get the target we should use for the output file.
|
|
Target*
|
|
target() const
|
|
{ return this->target_; }
|
|
|
|
// For each dynamic object, check whether we've seen all of its
|
|
// explicit dependencies.
|
|
void
|
|
check_dynamic_dependencies() const;
|
|
|
|
// Return whether an object was found in the system library
|
|
// directory.
|
|
bool
|
|
found_in_system_library_directory(const Object*) const;
|
|
|
|
// Iterate over all regular objects.
|
|
|
|
Relobj_iterator
|
|
relobj_begin() const
|
|
{ return this->relobj_list_.begin(); }
|
|
|
|
Relobj_iterator
|
|
relobj_end() const
|
|
{ return this->relobj_list_.end(); }
|
|
|
|
// Iterate over all dynamic objects.
|
|
|
|
Dynobj_iterator
|
|
dynobj_begin() const
|
|
{ return this->dynobj_list_.begin(); }
|
|
|
|
Dynobj_iterator
|
|
dynobj_end() const
|
|
{ return this->dynobj_list_.end(); }
|
|
|
|
// Return whether we have seen any dynamic objects.
|
|
bool
|
|
any_dynamic() const
|
|
{ return !this->dynobj_list_.empty(); }
|
|
|
|
// Return the number of input objects.
|
|
int
|
|
number_of_input_objects() const
|
|
{ return this->relobj_list_.size() + this->dynobj_list_.size(); }
|
|
|
|
private:
|
|
Input_objects(const Input_objects&);
|
|
Input_objects& operator=(const Input_objects&);
|
|
|
|
// The list of ordinary objects included in the link.
|
|
Relobj_list relobj_list_;
|
|
// The list of dynamic objects included in the link.
|
|
Dynobj_list dynobj_list_;
|
|
// The target.
|
|
Target* target_;
|
|
// SONAMEs that we have seen.
|
|
Unordered_set<std::string> sonames_;
|
|
// The directory in which we find the libc.so.
|
|
std::string system_library_directory_;
|
|
};
|
|
|
|
// Some of the information we pass to the relocation routines. We
|
|
// group this together to avoid passing a dozen different arguments.
|
|
|
|
template<int size, bool big_endian>
|
|
struct Relocate_info
|
|
{
|
|
// Command line options.
|
|
const General_options* options;
|
|
// Symbol table.
|
|
const Symbol_table* symtab;
|
|
// Layout.
|
|
const Layout* layout;
|
|
// Object being relocated.
|
|
Sized_relobj<size, big_endian>* object;
|
|
// Section index of relocation section.
|
|
unsigned int reloc_shndx;
|
|
// Section index of section being relocated.
|
|
unsigned int data_shndx;
|
|
|
|
// Return a string showing the location of a relocation. This is
|
|
// only used for error messages.
|
|
std::string
|
|
location(size_t relnum, off_t reloffset) const;
|
|
};
|
|
|
|
// Return an Object appropriate for the input file. P is BYTES long,
|
|
// and holds the ELF header.
|
|
|
|
extern Object*
|
|
make_elf_object(const std::string& name, Input_file*,
|
|
off_t offset, const unsigned char* p,
|
|
off_t bytes);
|
|
|
|
} // end namespace gold
|
|
|
|
#endif // !defined(GOLD_OBJECT_H)
|