mirror of
https://github.com/autc04/Retro68.git
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1185 lines
35 KiB
C++
1185 lines
35 KiB
C++
// layout.h -- lay out output file sections for gold -*- C++ -*-
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// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
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// Written by Ian Lance Taylor <iant@google.com>.
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// This file is part of gold.
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 3 of the License, or
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// (at your option) any later version.
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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// MA 02110-1301, USA.
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#ifndef GOLD_LAYOUT_H
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#define GOLD_LAYOUT_H
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#include <cstring>
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#include <list>
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#include <map>
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#include <string>
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#include <utility>
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#include <vector>
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#include "script.h"
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#include "workqueue.h"
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#include "object.h"
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#include "dynobj.h"
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#include "stringpool.h"
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namespace gold
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{
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class General_options;
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class Incremental_inputs;
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class Input_objects;
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class Mapfile;
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class Symbol_table;
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class Output_section_data;
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class Output_section;
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class Output_section_headers;
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class Output_segment_headers;
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class Output_file_header;
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class Output_segment;
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class Output_data;
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class Output_data_dynamic;
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class Output_symtab_xindex;
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class Output_reduced_debug_abbrev_section;
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class Output_reduced_debug_info_section;
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class Eh_frame;
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class Target;
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// This task function handles mapping the input sections to output
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// sections and laying them out in memory.
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class Layout_task_runner : public Task_function_runner
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{
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public:
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// OPTIONS is the command line options, INPUT_OBJECTS is the list of
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// input objects, SYMTAB is the symbol table, LAYOUT is the layout
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// object.
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Layout_task_runner(const General_options& options,
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const Input_objects* input_objects,
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Symbol_table* symtab,
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Target* target,
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Layout* layout,
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Mapfile* mapfile)
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: options_(options), input_objects_(input_objects), symtab_(symtab),
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target_(target), layout_(layout), mapfile_(mapfile)
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{ }
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// Run the operation.
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void
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run(Workqueue*, const Task*);
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private:
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Layout_task_runner(const Layout_task_runner&);
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Layout_task_runner& operator=(const Layout_task_runner&);
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const General_options& options_;
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const Input_objects* input_objects_;
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Symbol_table* symtab_;
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Target* target_;
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Layout* layout_;
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Mapfile* mapfile_;
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};
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// This class holds information about the comdat group or
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// .gnu.linkonce section that will be kept for a given signature.
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class Kept_section
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{
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private:
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// For a comdat group, we build a mapping from the name of each
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// section in the group to the section index and the size in object.
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// When we discard a group in some other object file, we use this
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// map to figure out which kept section the discarded section is
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// associated with. We then use that mapping when processing relocs
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// against discarded sections.
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struct Comdat_section_info
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{
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// The section index.
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unsigned int shndx;
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// The section size.
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uint64_t size;
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Comdat_section_info(unsigned int a_shndx, uint64_t a_size)
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: shndx(a_shndx), size(a_size)
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{ }
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};
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// Most comdat groups have only one or two sections, so we use a
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// std::map rather than an Unordered_map to optimize for that case
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// without paying too heavily for groups with more sections.
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typedef std::map<std::string, Comdat_section_info> Comdat_group;
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public:
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Kept_section()
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: object_(NULL), shndx_(0), is_comdat_(false), is_group_name_(false)
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{ this->u_.linkonce_size = 0; }
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// We need to support copies for the signature map in the Layout
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// object, but we should never copy an object after it has been
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// marked as a comdat section.
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Kept_section(const Kept_section& k)
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: object_(k.object_), shndx_(k.shndx_), is_comdat_(false),
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is_group_name_(k.is_group_name_)
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{
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gold_assert(!k.is_comdat_);
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this->u_.linkonce_size = 0;
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}
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~Kept_section()
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{
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if (this->is_comdat_)
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delete this->u_.group_sections;
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}
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// The object where this section lives.
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Relobj*
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object() const
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{ return this->object_; }
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// Set the object.
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void
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set_object(Relobj* object)
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{
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gold_assert(this->object_ == NULL);
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this->object_ = object;
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}
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// The section index.
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unsigned int
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shndx() const
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{ return this->shndx_; }
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// Set the section index.
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void
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set_shndx(unsigned int shndx)
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{
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gold_assert(this->shndx_ == 0);
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this->shndx_ = shndx;
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}
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// Whether this is a comdat group.
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bool
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is_comdat() const
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{ return this->is_comdat_; }
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// Set that this is a comdat group.
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void
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set_is_comdat()
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{
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gold_assert(!this->is_comdat_);
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this->is_comdat_ = true;
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this->u_.group_sections = new Comdat_group();
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}
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// Whether this is associated with the name of a group or section
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// rather than the symbol name derived from a linkonce section.
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bool
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is_group_name() const
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{ return this->is_group_name_; }
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// Note that this represents a comdat group rather than a single
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// linkonce section.
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void
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set_is_group_name()
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{ this->is_group_name_ = true; }
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// Add a section to the group list.
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void
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add_comdat_section(const std::string& name, unsigned int shndx,
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uint64_t size)
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{
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gold_assert(this->is_comdat_);
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Comdat_section_info sinfo(shndx, size);
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this->u_.group_sections->insert(std::make_pair(name, sinfo));
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}
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// Look for a section name in the group list, and return whether it
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// was found. If found, returns the section index and size.
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bool
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find_comdat_section(const std::string& name, unsigned int *pshndx,
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uint64_t *psize) const
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{
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gold_assert(this->is_comdat_);
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Comdat_group::const_iterator p = this->u_.group_sections->find(name);
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if (p == this->u_.group_sections->end())
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return false;
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*pshndx = p->second.shndx;
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*psize = p->second.size;
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return true;
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}
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// If there is only one section in the group list, return true, and
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// return the section index and size.
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bool
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find_single_comdat_section(unsigned int *pshndx, uint64_t *psize) const
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{
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gold_assert(this->is_comdat_);
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if (this->u_.group_sections->size() != 1)
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return false;
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Comdat_group::const_iterator p = this->u_.group_sections->begin();
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*pshndx = p->second.shndx;
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*psize = p->second.size;
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return true;
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}
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// Return the size of a linkonce section.
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uint64_t
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linkonce_size() const
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{
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gold_assert(!this->is_comdat_);
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return this->u_.linkonce_size;
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}
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// Set the size of a linkonce section.
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void
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set_linkonce_size(uint64_t size)
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{
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gold_assert(!this->is_comdat_);
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this->u_.linkonce_size = size;
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}
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private:
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// No assignment.
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Kept_section& operator=(const Kept_section&);
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// The object containing the comdat group or .gnu.linkonce section.
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Relobj* object_;
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// Index of the group section for comdats and the section itself for
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// .gnu.linkonce.
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unsigned int shndx_;
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// True if this is for a comdat group rather than a .gnu.linkonce
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// section.
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bool is_comdat_;
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// The Kept_sections are values of a mapping, that maps names to
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// them. This field is true if this struct is associated with the
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// name of a comdat or .gnu.linkonce, false if it is associated with
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// the name of a symbol obtained from the .gnu.linkonce.* name
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// through some heuristics.
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bool is_group_name_;
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union
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{
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// If the is_comdat_ field is true, this holds a map from names of
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// the sections in the group to section indexes in object_ and to
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// section sizes.
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Comdat_group* group_sections;
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// If the is_comdat_ field is false, this holds the size of the
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// single section.
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uint64_t linkonce_size;
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} u_;
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};
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// This class handles the details of laying out input sections.
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class Layout
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{
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public:
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Layout(int number_of_input_files, Script_options*);
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~Layout()
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{
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delete this->relaxation_debug_check_;
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delete this->segment_states_;
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}
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// Given an input section SHNDX, named NAME, with data in SHDR, from
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// the object file OBJECT, return the output section where this
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// input section should go. RELOC_SHNDX is the index of a
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// relocation section which applies to this section, or 0 if none,
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// or -1U if more than one. RELOC_TYPE is the type of the
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// relocation section if there is one. Set *OFFSET to the offset
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// within the output section.
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template<int size, bool big_endian>
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Output_section*
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layout(Sized_relobj<size, big_endian> *object, unsigned int shndx,
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const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
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unsigned int reloc_shndx, unsigned int reloc_type, off_t* offset);
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// Layout an input reloc section when doing a relocatable link. The
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// section is RELOC_SHNDX in OBJECT, with data in SHDR.
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// DATA_SECTION is the reloc section to which it refers. RR is the
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// relocatable information.
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template<int size, bool big_endian>
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Output_section*
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layout_reloc(Sized_relobj<size, big_endian>* object,
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unsigned int reloc_shndx,
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const elfcpp::Shdr<size, big_endian>& shdr,
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Output_section* data_section,
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Relocatable_relocs* rr);
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// Layout a group section when doing a relocatable link.
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template<int size, bool big_endian>
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void
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layout_group(Symbol_table* symtab,
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Sized_relobj<size, big_endian>* object,
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unsigned int group_shndx,
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const char* group_section_name,
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const char* signature,
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const elfcpp::Shdr<size, big_endian>& shdr,
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elfcpp::Elf_Word flags,
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std::vector<unsigned int>* shndxes);
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// Like layout, only for exception frame sections. OBJECT is an
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// object file. SYMBOLS is the contents of the symbol table
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// section, with size SYMBOLS_SIZE. SYMBOL_NAMES is the contents of
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// the symbol name section, with size SYMBOL_NAMES_SIZE. SHNDX is a
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// .eh_frame section in OBJECT. SHDR is the section header.
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// RELOC_SHNDX is the index of a relocation section which applies to
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// this section, or 0 if none, or -1U if more than one. RELOC_TYPE
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// is the type of the relocation section if there is one. This
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// returns the output section, and sets *OFFSET to the offset.
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template<int size, bool big_endian>
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Output_section*
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layout_eh_frame(Sized_relobj<size, big_endian>* object,
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const unsigned char* symbols,
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off_t symbols_size,
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const unsigned char* symbol_names,
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off_t symbol_names_size,
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unsigned int shndx,
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const elfcpp::Shdr<size, big_endian>& shdr,
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unsigned int reloc_shndx, unsigned int reloc_type,
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off_t* offset);
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// Handle a GNU stack note. This is called once per input object
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// file. SEEN_GNU_STACK is true if the object file has a
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// .note.GNU-stack section. GNU_STACK_FLAGS is the section flags
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// from that section if there was one.
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void
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layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags);
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// Add an Output_section_data to the layout. This is used for
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// special sections like the GOT section. IS_DYNAMIC_LINKER_SECTION
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// is true for sections which are used by the dynamic linker, such
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// as dynamic reloc sections.
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Output_section*
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add_output_section_data(const char* name, elfcpp::Elf_Word type,
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elfcpp::Elf_Xword flags,
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Output_section_data*, bool is_dynamic_linker_section);
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// Create dynamic sections if necessary.
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void
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create_initial_dynamic_sections(Symbol_table*);
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// Define __start and __stop symbols for output sections.
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void
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define_section_symbols(Symbol_table*);
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// Create automatic note sections.
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void
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create_notes();
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// Create sections for linker scripts.
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void
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create_script_sections()
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{ this->script_options_->create_script_sections(this); }
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// Define symbols from any linker script.
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void
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define_script_symbols(Symbol_table* symtab)
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{ this->script_options_->add_symbols_to_table(symtab); }
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// Define symbols for group signatures.
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void
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define_group_signatures(Symbol_table*);
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// Return the Stringpool used for symbol names.
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const Stringpool*
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sympool() const
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{ return &this->sympool_; }
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// Return the Stringpool used for dynamic symbol names and dynamic
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// tags.
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const Stringpool*
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dynpool() const
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{ return &this->dynpool_; }
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// Return the symtab_xindex section used to hold large section
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// indexes for the normal symbol table.
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Output_symtab_xindex*
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symtab_xindex() const
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{ return this->symtab_xindex_; }
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// Return the dynsym_xindex section used to hold large section
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// indexes for the dynamic symbol table.
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Output_symtab_xindex*
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dynsym_xindex() const
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{ return this->dynsym_xindex_; }
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// Return whether a section is a .gnu.linkonce section, given the
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// section name.
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static inline bool
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is_linkonce(const char* name)
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{ return strncmp(name, ".gnu.linkonce", sizeof(".gnu.linkonce") - 1) == 0; }
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// Return true if a section is a debugging section.
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static inline bool
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is_debug_info_section(const char* name)
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{
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// Debugging sections can only be recognized by name.
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return (strncmp(name, ".debug", sizeof(".debug") - 1) == 0
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|| strncmp(name, ".gnu.linkonce.wi.",
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sizeof(".gnu.linkonce.wi.") - 1) == 0
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|| strncmp(name, ".line", sizeof(".line") - 1) == 0
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|| strncmp(name, ".stab", sizeof(".stab") - 1) == 0);
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}
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// Check if a comdat group or .gnu.linkonce section with the given
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// NAME is selected for the link. If there is already a section,
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// *KEPT_SECTION is set to point to the signature and the function
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// returns false. Otherwise, OBJECT, SHNDX,IS_COMDAT, and
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// IS_GROUP_NAME are recorded for this NAME in the layout object,
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// *KEPT_SECTION is set to the internal copy and the function return
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// false.
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bool
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find_or_add_kept_section(const std::string& name, Relobj* object,
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unsigned int shndx, bool is_comdat,
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bool is_group_name, Kept_section** kept_section);
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// Finalize the layout after all the input sections have been added.
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off_t
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finalize(const Input_objects*, Symbol_table*, Target*, const Task*);
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// Return whether any sections require postprocessing.
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bool
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any_postprocessing_sections() const
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{ return this->any_postprocessing_sections_; }
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// Return the size of the output file.
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off_t
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output_file_size() const
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{ return this->output_file_size_; }
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// Return the TLS segment. This will return NULL if there isn't
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// one.
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Output_segment*
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tls_segment() const
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{ return this->tls_segment_; }
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// Return the normal symbol table.
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Output_section*
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symtab_section() const
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{
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gold_assert(this->symtab_section_ != NULL);
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return this->symtab_section_;
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}
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// Return the dynamic symbol table.
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Output_section*
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dynsym_section() const
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{
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gold_assert(this->dynsym_section_ != NULL);
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return this->dynsym_section_;
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}
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// Return the dynamic tags.
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Output_data_dynamic*
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dynamic_data() const
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{ return this->dynamic_data_; }
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// Write out the output sections.
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void
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write_output_sections(Output_file* of) const;
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// Write out data not associated with an input file or the symbol
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// table.
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void
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write_data(const Symbol_table*, Output_file*) const;
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// Write out output sections which can not be written until all the
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// input sections are complete.
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void
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write_sections_after_input_sections(Output_file* of);
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// Return an output section named NAME, or NULL if there is none.
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Output_section*
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find_output_section(const char* name) const;
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// Return an output segment of type TYPE, with segment flags SET set
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// and segment flags CLEAR clear. Return NULL if there is none.
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Output_segment*
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find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
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elfcpp::Elf_Word clear) const;
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// Return the number of segments we expect to produce.
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size_t
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expected_segment_count() const;
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|
|
// Set a flag to indicate that an object file uses the static TLS model.
|
|
void
|
|
set_has_static_tls()
|
|
{ this->has_static_tls_ = true; }
|
|
|
|
// Return true if any object file uses the static TLS model.
|
|
bool
|
|
has_static_tls() const
|
|
{ return this->has_static_tls_; }
|
|
|
|
// Return the options which may be set by a linker script.
|
|
Script_options*
|
|
script_options()
|
|
{ return this->script_options_; }
|
|
|
|
const Script_options*
|
|
script_options() const
|
|
{ return this->script_options_; }
|
|
|
|
// Return the object managing inputs in incremental build. NULL in
|
|
// non-incremental builds.
|
|
Incremental_inputs*
|
|
incremental_inputs()
|
|
{ return this->incremental_inputs_; }
|
|
|
|
// Compute and write out the build ID if needed.
|
|
void
|
|
write_build_id(Output_file*) const;
|
|
|
|
// Rewrite output file in binary format.
|
|
void
|
|
write_binary(Output_file* in) const;
|
|
|
|
// Print output sections to the map file.
|
|
void
|
|
print_to_mapfile(Mapfile*) const;
|
|
|
|
// Dump statistical information to stderr.
|
|
void
|
|
print_stats() const;
|
|
|
|
// A list of segments.
|
|
|
|
typedef std::vector<Output_segment*> Segment_list;
|
|
|
|
// A list of sections.
|
|
|
|
typedef std::vector<Output_section*> Section_list;
|
|
|
|
// The list of information to write out which is not attached to
|
|
// either a section or a segment.
|
|
typedef std::vector<Output_data*> Data_list;
|
|
|
|
// Store the allocated sections into the section list. This is used
|
|
// by the linker script code.
|
|
void
|
|
get_allocated_sections(Section_list*) const;
|
|
|
|
// Make a section for a linker script to hold data.
|
|
Output_section*
|
|
make_output_section_for_script(const char* name);
|
|
|
|
// Make a segment. This is used by the linker script code.
|
|
Output_segment*
|
|
make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags);
|
|
|
|
// Return the number of segments.
|
|
size_t
|
|
segment_count() const
|
|
{ return this->segment_list_.size(); }
|
|
|
|
// Map from section flags to segment flags.
|
|
static elfcpp::Elf_Word
|
|
section_flags_to_segment(elfcpp::Elf_Xword flags);
|
|
|
|
// Attach sections to segments.
|
|
void
|
|
attach_sections_to_segments();
|
|
|
|
// For relaxation clean up, we need to know output section data created
|
|
// from a linker script.
|
|
void
|
|
new_output_section_data_from_script(Output_section_data* posd)
|
|
{
|
|
if (this->record_output_section_data_from_script_)
|
|
this->script_output_section_data_list_.push_back(posd);
|
|
}
|
|
|
|
// Return section list.
|
|
const Section_list&
|
|
section_list() const
|
|
{ return this->section_list_; }
|
|
|
|
private:
|
|
Layout(const Layout&);
|
|
Layout& operator=(const Layout&);
|
|
|
|
// Mapping from input section names to output section names.
|
|
struct Section_name_mapping
|
|
{
|
|
const char* from;
|
|
int fromlen;
|
|
const char* to;
|
|
int tolen;
|
|
};
|
|
static const Section_name_mapping section_name_mapping[];
|
|
static const int section_name_mapping_count;
|
|
|
|
// During a relocatable link, a list of group sections and
|
|
// signatures.
|
|
struct Group_signature
|
|
{
|
|
// The group section.
|
|
Output_section* section;
|
|
// The signature.
|
|
const char* signature;
|
|
|
|
Group_signature()
|
|
: section(NULL), signature(NULL)
|
|
{ }
|
|
|
|
Group_signature(Output_section* sectiona, const char* signaturea)
|
|
: section(sectiona), signature(signaturea)
|
|
{ }
|
|
};
|
|
typedef std::vector<Group_signature> Group_signatures;
|
|
|
|
// Create a note section, filling in the header.
|
|
Output_section*
|
|
create_note(const char* name, int note_type, const char *section_name,
|
|
size_t descsz, bool allocate, size_t* trailing_padding);
|
|
|
|
// Create a note section for gold version.
|
|
void
|
|
create_gold_note();
|
|
|
|
// Record whether the stack must be executable.
|
|
void
|
|
create_executable_stack_info();
|
|
|
|
// Create a build ID note if needed.
|
|
void
|
|
create_build_id();
|
|
|
|
// Link .stab and .stabstr sections.
|
|
void
|
|
link_stabs_sections();
|
|
|
|
// Create .gnu_incremental_inputs and .gnu_incremental_strtab sections needed
|
|
// for the next run of incremental linking to check what has changed.
|
|
void
|
|
create_incremental_info_sections();
|
|
|
|
// Find the first read-only PT_LOAD segment, creating one if
|
|
// necessary.
|
|
Output_segment*
|
|
find_first_load_seg();
|
|
|
|
// Count the local symbols in the regular symbol table and the dynamic
|
|
// symbol table, and build the respective string pools.
|
|
void
|
|
count_local_symbols(const Task*, const Input_objects*);
|
|
|
|
// Create the output sections for the symbol table.
|
|
void
|
|
create_symtab_sections(const Input_objects*, Symbol_table*,
|
|
unsigned int, off_t*);
|
|
|
|
// Create the .shstrtab section.
|
|
Output_section*
|
|
create_shstrtab();
|
|
|
|
// Create the section header table.
|
|
void
|
|
create_shdrs(const Output_section* shstrtab_section, off_t*);
|
|
|
|
// Create the dynamic symbol table.
|
|
void
|
|
create_dynamic_symtab(const Input_objects*, Symbol_table*,
|
|
Output_section** pdynstr,
|
|
unsigned int* plocal_dynamic_count,
|
|
std::vector<Symbol*>* pdynamic_symbols,
|
|
Versions* versions);
|
|
|
|
// Assign offsets to each local portion of the dynamic symbol table.
|
|
void
|
|
assign_local_dynsym_offsets(const Input_objects*);
|
|
|
|
// Finish the .dynamic section and PT_DYNAMIC segment.
|
|
void
|
|
finish_dynamic_section(const Input_objects*, const Symbol_table*);
|
|
|
|
// Create the .interp section and PT_INTERP segment.
|
|
void
|
|
create_interp(const Target* target);
|
|
|
|
// Create the version sections.
|
|
void
|
|
create_version_sections(const Versions*,
|
|
const Symbol_table*,
|
|
unsigned int local_symcount,
|
|
const std::vector<Symbol*>& dynamic_symbols,
|
|
const Output_section* dynstr);
|
|
|
|
template<int size, bool big_endian>
|
|
void
|
|
sized_create_version_sections(const Versions* versions,
|
|
const Symbol_table*,
|
|
unsigned int local_symcount,
|
|
const std::vector<Symbol*>& dynamic_symbols,
|
|
const Output_section* dynstr);
|
|
|
|
// Return whether to include this section in the link.
|
|
template<int size, bool big_endian>
|
|
bool
|
|
include_section(Sized_relobj<size, big_endian>* object, const char* name,
|
|
const elfcpp::Shdr<size, big_endian>&);
|
|
|
|
// Return the output section name to use given an input section
|
|
// name. Set *PLEN to the length of the name. *PLEN must be
|
|
// initialized to the length of NAME.
|
|
static const char*
|
|
output_section_name(const char* name, size_t* plen);
|
|
|
|
// Return the number of allocated output sections.
|
|
size_t
|
|
allocated_output_section_count() const;
|
|
|
|
// Return the output section for NAME, TYPE and FLAGS.
|
|
Output_section*
|
|
get_output_section(const char* name, Stringpool::Key name_key,
|
|
elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
|
|
bool is_interp, bool is_dynamic_linker_section);
|
|
|
|
// Choose the output section for NAME in RELOBJ.
|
|
Output_section*
|
|
choose_output_section(const Relobj* relobj, const char* name,
|
|
elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
|
|
bool is_input_section, bool is_interp,
|
|
bool is_dynamic_linker_section);
|
|
|
|
// Create a new Output_section.
|
|
Output_section*
|
|
make_output_section(const char* name, elfcpp::Elf_Word type,
|
|
elfcpp::Elf_Xword flags, bool is_interp,
|
|
bool is_dynamic_linker_section);
|
|
|
|
// Attach a section to a segment.
|
|
void
|
|
attach_section_to_segment(Output_section*);
|
|
|
|
// Attach an allocated section to a segment.
|
|
void
|
|
attach_allocated_section_to_segment(Output_section*);
|
|
|
|
// Set the final file offsets of all the segments.
|
|
off_t
|
|
set_segment_offsets(const Target*, Output_segment*, unsigned int* pshndx);
|
|
|
|
// Set the file offsets of the sections when doing a relocatable
|
|
// link.
|
|
off_t
|
|
set_relocatable_section_offsets(Output_data*, unsigned int* pshndx);
|
|
|
|
// Set the final file offsets of all the sections not associated
|
|
// with a segment. We set section offsets in three passes: the
|
|
// first handles all allocated sections, the second sections that
|
|
// require postprocessing, and the last the late-bound STRTAB
|
|
// sections (probably only shstrtab, which is the one we care about
|
|
// because it holds section names).
|
|
enum Section_offset_pass
|
|
{
|
|
BEFORE_INPUT_SECTIONS_PASS,
|
|
POSTPROCESSING_SECTIONS_PASS,
|
|
STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
|
|
};
|
|
off_t
|
|
set_section_offsets(off_t, Section_offset_pass pass);
|
|
|
|
// Set the final section indexes of all the sections not associated
|
|
// with a segment. Returns the next unused index.
|
|
unsigned int
|
|
set_section_indexes(unsigned int pshndx);
|
|
|
|
// Set the section addresses when using a script.
|
|
Output_segment*
|
|
set_section_addresses_from_script(Symbol_table*);
|
|
|
|
// Find appropriate places or orphan sections in a script.
|
|
void
|
|
place_orphan_sections_in_script();
|
|
|
|
// Return whether SEG1 comes before SEG2 in the output file.
|
|
static bool
|
|
segment_precedes(const Output_segment* seg1, const Output_segment* seg2);
|
|
|
|
// Use to save and restore segments during relaxation.
|
|
typedef Unordered_map<const Output_segment*, const Output_segment*>
|
|
Segment_states;
|
|
|
|
// Save states of current output segments.
|
|
void
|
|
save_segments(Segment_states*);
|
|
|
|
// Restore output segment states.
|
|
void
|
|
restore_segments(const Segment_states*);
|
|
|
|
// Clean up after relaxation so that it is possible to lay out the
|
|
// sections and segments again.
|
|
void
|
|
clean_up_after_relaxation();
|
|
|
|
// Doing preparation work for relaxation. This is factored out to make
|
|
// Layout::finalized a bit smaller and easier to read.
|
|
void
|
|
prepare_for_relaxation();
|
|
|
|
// Main body of the relaxation loop, which lays out the section.
|
|
off_t
|
|
relaxation_loop_body(int, Target*, Symbol_table*, Output_segment**,
|
|
Output_segment*, Output_segment_headers*,
|
|
Output_file_header*, unsigned int*);
|
|
|
|
// A mapping used for kept comdats/.gnu.linkonce group signatures.
|
|
typedef Unordered_map<std::string, Kept_section> Signatures;
|
|
|
|
// Mapping from input section name/type/flags to output section. We
|
|
// use canonicalized strings here.
|
|
|
|
typedef std::pair<Stringpool::Key,
|
|
std::pair<elfcpp::Elf_Word, elfcpp::Elf_Xword> > Key;
|
|
|
|
struct Hash_key
|
|
{
|
|
size_t
|
|
operator()(const Key& k) const;
|
|
};
|
|
|
|
typedef Unordered_map<Key, Output_section*, Hash_key> Section_name_map;
|
|
|
|
// A comparison class for segments.
|
|
|
|
struct Compare_segments
|
|
{
|
|
bool
|
|
operator()(const Output_segment* seg1, const Output_segment* seg2)
|
|
{ return Layout::segment_precedes(seg1, seg2); }
|
|
};
|
|
|
|
typedef std::vector<Output_section_data*> Output_section_data_list;
|
|
|
|
// Debug checker class.
|
|
class Relaxation_debug_check
|
|
{
|
|
public:
|
|
Relaxation_debug_check()
|
|
: section_infos_()
|
|
{ }
|
|
|
|
// Check that sections and special data are in reset states.
|
|
void
|
|
check_output_data_for_reset_values(const Layout::Section_list&,
|
|
const Layout::Data_list&);
|
|
|
|
// Record information of a section list.
|
|
void
|
|
read_sections(const Layout::Section_list&);
|
|
|
|
// Verify a section list with recorded information.
|
|
void
|
|
verify_sections(const Layout::Section_list&);
|
|
|
|
private:
|
|
// Information we care about a section.
|
|
struct Section_info
|
|
{
|
|
// Output section described by this.
|
|
Output_section* output_section;
|
|
// Load address.
|
|
uint64_t address;
|
|
// Data size.
|
|
off_t data_size;
|
|
// File offset.
|
|
off_t offset;
|
|
};
|
|
|
|
// Section information.
|
|
std::vector<Section_info> section_infos_;
|
|
};
|
|
|
|
// The number of input files, for sizing tables.
|
|
int number_of_input_files_;
|
|
// Information set by scripts or by command line options.
|
|
Script_options* script_options_;
|
|
// The output section names.
|
|
Stringpool namepool_;
|
|
// The output symbol names.
|
|
Stringpool sympool_;
|
|
// The dynamic strings, if needed.
|
|
Stringpool dynpool_;
|
|
// The list of group sections and linkonce sections which we have seen.
|
|
Signatures signatures_;
|
|
// The mapping from input section name/type/flags to output sections.
|
|
Section_name_map section_name_map_;
|
|
// The list of output segments.
|
|
Segment_list segment_list_;
|
|
// The list of output sections.
|
|
Section_list section_list_;
|
|
// The list of output sections which are not attached to any output
|
|
// segment.
|
|
Section_list unattached_section_list_;
|
|
// The list of unattached Output_data objects which require special
|
|
// handling because they are not Output_sections.
|
|
Data_list special_output_list_;
|
|
// The section headers.
|
|
Output_section_headers* section_headers_;
|
|
// A pointer to the PT_TLS segment if there is one.
|
|
Output_segment* tls_segment_;
|
|
// A pointer to the PT_GNU_RELRO segment if there is one.
|
|
Output_segment* relro_segment_;
|
|
// The SHT_SYMTAB output section.
|
|
Output_section* symtab_section_;
|
|
// The SHT_SYMTAB_SHNDX for the regular symbol table if there is one.
|
|
Output_symtab_xindex* symtab_xindex_;
|
|
// The SHT_DYNSYM output section if there is one.
|
|
Output_section* dynsym_section_;
|
|
// The SHT_SYMTAB_SHNDX for the dynamic symbol table if there is one.
|
|
Output_symtab_xindex* dynsym_xindex_;
|
|
// The SHT_DYNAMIC output section if there is one.
|
|
Output_section* dynamic_section_;
|
|
// The dynamic data which goes into dynamic_section_.
|
|
Output_data_dynamic* dynamic_data_;
|
|
// The exception frame output section if there is one.
|
|
Output_section* eh_frame_section_;
|
|
// The exception frame data for eh_frame_section_.
|
|
Eh_frame* eh_frame_data_;
|
|
// Whether we have added eh_frame_data_ to the .eh_frame section.
|
|
bool added_eh_frame_data_;
|
|
// The exception frame header output section if there is one.
|
|
Output_section* eh_frame_hdr_section_;
|
|
// The space for the build ID checksum if there is one.
|
|
Output_section_data* build_id_note_;
|
|
// The output section containing dwarf abbreviations
|
|
Output_reduced_debug_abbrev_section* debug_abbrev_;
|
|
// The output section containing the dwarf debug info tree
|
|
Output_reduced_debug_info_section* debug_info_;
|
|
// A list of group sections and their signatures.
|
|
Group_signatures group_signatures_;
|
|
// The size of the output file.
|
|
off_t output_file_size_;
|
|
// Whether we have attached the sections to the segments.
|
|
bool sections_are_attached_;
|
|
// Whether we have seen an object file marked to require an
|
|
// executable stack.
|
|
bool input_requires_executable_stack_;
|
|
// Whether we have seen at least one object file with an executable
|
|
// stack marker.
|
|
bool input_with_gnu_stack_note_;
|
|
// Whether we have seen at least one object file without an
|
|
// executable stack marker.
|
|
bool input_without_gnu_stack_note_;
|
|
// Whether we have seen an object file that uses the static TLS model.
|
|
bool has_static_tls_;
|
|
// Whether any sections require postprocessing.
|
|
bool any_postprocessing_sections_;
|
|
// Whether we have resized the signatures_ hash table.
|
|
bool resized_signatures_;
|
|
// Whether we have created a .stab*str output section.
|
|
bool have_stabstr_section_;
|
|
// In incremental build, holds information check the inputs and build the
|
|
// .gnu_incremental_inputs section.
|
|
Incremental_inputs* incremental_inputs_;
|
|
// Whether we record output section data created in script
|
|
bool record_output_section_data_from_script_;
|
|
// List of output data that needs to be removed at relexation clean up.
|
|
Output_section_data_list script_output_section_data_list_;
|
|
// Structure to save segment states before entering the relaxation loop.
|
|
Segment_states* segment_states_;
|
|
// A relaxation debug checker. We only create one when in debugging mode.
|
|
Relaxation_debug_check* relaxation_debug_check_;
|
|
};
|
|
|
|
// This task handles writing out data in output sections which is not
|
|
// part of an input section, or which requires special handling. When
|
|
// this is done, it unblocks both output_sections_blocker and
|
|
// final_blocker.
|
|
|
|
class Write_sections_task : public Task
|
|
{
|
|
public:
|
|
Write_sections_task(const Layout* layout, Output_file* of,
|
|
Task_token* output_sections_blocker,
|
|
Task_token* final_blocker)
|
|
: layout_(layout), of_(of),
|
|
output_sections_blocker_(output_sections_blocker),
|
|
final_blocker_(final_blocker)
|
|
{ }
|
|
|
|
// The standard Task methods.
|
|
|
|
Task_token*
|
|
is_runnable();
|
|
|
|
void
|
|
locks(Task_locker*);
|
|
|
|
void
|
|
run(Workqueue*);
|
|
|
|
std::string
|
|
get_name() const
|
|
{ return "Write_sections_task"; }
|
|
|
|
private:
|
|
class Write_sections_locker;
|
|
|
|
const Layout* layout_;
|
|
Output_file* of_;
|
|
Task_token* output_sections_blocker_;
|
|
Task_token* final_blocker_;
|
|
};
|
|
|
|
// This task handles writing out data which is not part of a section
|
|
// or segment.
|
|
|
|
class Write_data_task : public Task
|
|
{
|
|
public:
|
|
Write_data_task(const Layout* layout, const Symbol_table* symtab,
|
|
Output_file* of, Task_token* final_blocker)
|
|
: layout_(layout), symtab_(symtab), of_(of), final_blocker_(final_blocker)
|
|
{ }
|
|
|
|
// The standard Task methods.
|
|
|
|
Task_token*
|
|
is_runnable();
|
|
|
|
void
|
|
locks(Task_locker*);
|
|
|
|
void
|
|
run(Workqueue*);
|
|
|
|
std::string
|
|
get_name() const
|
|
{ return "Write_data_task"; }
|
|
|
|
private:
|
|
const Layout* layout_;
|
|
const Symbol_table* symtab_;
|
|
Output_file* of_;
|
|
Task_token* final_blocker_;
|
|
};
|
|
|
|
// This task handles writing out the global symbols.
|
|
|
|
class Write_symbols_task : public Task
|
|
{
|
|
public:
|
|
Write_symbols_task(const Layout* layout, const Symbol_table* symtab,
|
|
const Input_objects* input_objects,
|
|
const Stringpool* sympool, const Stringpool* dynpool,
|
|
Output_file* of, Task_token* final_blocker)
|
|
: layout_(layout), symtab_(symtab), input_objects_(input_objects),
|
|
sympool_(sympool), dynpool_(dynpool), of_(of),
|
|
final_blocker_(final_blocker)
|
|
{ }
|
|
|
|
// The standard Task methods.
|
|
|
|
Task_token*
|
|
is_runnable();
|
|
|
|
void
|
|
locks(Task_locker*);
|
|
|
|
void
|
|
run(Workqueue*);
|
|
|
|
std::string
|
|
get_name() const
|
|
{ return "Write_symbols_task"; }
|
|
|
|
private:
|
|
const Layout* layout_;
|
|
const Symbol_table* symtab_;
|
|
const Input_objects* input_objects_;
|
|
const Stringpool* sympool_;
|
|
const Stringpool* dynpool_;
|
|
Output_file* of_;
|
|
Task_token* final_blocker_;
|
|
};
|
|
|
|
// This task handles writing out data in output sections which can't
|
|
// be written out until all the input sections have been handled.
|
|
// This is for sections whose contents is based on the contents of
|
|
// other output sections.
|
|
|
|
class Write_after_input_sections_task : public Task
|
|
{
|
|
public:
|
|
Write_after_input_sections_task(Layout* layout, Output_file* of,
|
|
Task_token* input_sections_blocker,
|
|
Task_token* final_blocker)
|
|
: layout_(layout), of_(of),
|
|
input_sections_blocker_(input_sections_blocker),
|
|
final_blocker_(final_blocker)
|
|
{ }
|
|
|
|
// The standard Task methods.
|
|
|
|
Task_token*
|
|
is_runnable();
|
|
|
|
void
|
|
locks(Task_locker*);
|
|
|
|
void
|
|
run(Workqueue*);
|
|
|
|
std::string
|
|
get_name() const
|
|
{ return "Write_after_input_sections_task"; }
|
|
|
|
private:
|
|
Layout* layout_;
|
|
Output_file* of_;
|
|
Task_token* input_sections_blocker_;
|
|
Task_token* final_blocker_;
|
|
};
|
|
|
|
// This task function handles closing the file.
|
|
|
|
class Close_task_runner : public Task_function_runner
|
|
{
|
|
public:
|
|
Close_task_runner(const General_options* options, const Layout* layout,
|
|
Output_file* of)
|
|
: options_(options), layout_(layout), of_(of)
|
|
{ }
|
|
|
|
// Run the operation.
|
|
void
|
|
run(Workqueue*, const Task*);
|
|
|
|
private:
|
|
const General_options* options_;
|
|
const Layout* layout_;
|
|
Output_file* of_;
|
|
};
|
|
|
|
// A small helper function to align an address.
|
|
|
|
inline uint64_t
|
|
align_address(uint64_t address, uint64_t addralign)
|
|
{
|
|
if (addralign != 0)
|
|
address = (address + addralign - 1) &~ (addralign - 1);
|
|
return address;
|
|
}
|
|
|
|
} // End namespace gold.
|
|
|
|
#endif // !defined(GOLD_LAYOUT_H)
|