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// layout.h -- lay out output file sections for gold -*- C++ -*-
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// Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012
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// Free Software Foundation, Inc.
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// Written by Ian Lance Taylor <iant@google.com>.
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// This file is part of gold.
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 3 of the License, or
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// (at your option) any later version.
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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// MA 02110-1301, USA.
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#include "workqueue.h"
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#include "stringpool.h"
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class General_options;
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class Incremental_inputs;
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class Incremental_binary;
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class Output_section_data;
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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_data_reloc_generic;
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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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// Return TRUE if SECNAME is the name of a compressed debug section.
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is_compressed_debug_section(const char* secname);
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// Maintain a list of free space within a section, segment, or file.
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// Used for incremental update links.
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Free_list_node(off_t start, off_t end)
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: start_(start), end_(end)
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typedef std::list<Free_list_node>::const_iterator Const_iterator;
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: list_(), last_remove_(list_.begin()), extend_(false), length_(0),
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// Initialize the free list for a section of length LEN.
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// If EXTEND is true, free space may be allocated past the end.
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init(off_t len, bool extend);
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// Set the minimum hole size that is allowed when allocating
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// from the free list.
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set_min_hole_size(off_t min_hole)
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{ this->min_hole_ = min_hole; }
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// Remove a chunk from the free list.
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remove(off_t start, off_t end);
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// Allocate a chunk of space from the free list of length LEN,
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// with alignment ALIGN, and minimum offset MINOFF.
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allocate(off_t len, uint64_t align, off_t minoff);
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// Return an iterator for the beginning of the free list.
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{ return this->list_.begin(); }
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// Return an iterator for the end of the free list.
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{ return this->list_.end(); }
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// Dump the free list (for debugging).
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// Print usage statistics.
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typedef std::list<Free_list_node>::iterator Iterator;
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std::list<Free_list_node> list_;
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// The last node visited during a remove operation.
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Iterator last_remove_;
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// Whether we can extend past the original length.
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// The total length of the section, segment, or file.
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// The minimum hole size allowed. When allocating from the free list,
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// we must not leave a hole smaller than this.
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// The total number of free lists used.
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static unsigned int num_lists;
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// The total number of free list nodes used.
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static unsigned int num_nodes;
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// The total number of calls to Free_list::remove.
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static unsigned int num_removes;
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// The total number of nodes visited during calls to Free_list::remove.
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static unsigned int num_remove_visits;
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// The total number of calls to Free_list::allocate.
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static unsigned int num_allocates;
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// The total number of nodes visited during calls to Free_list::allocate.
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static unsigned int num_allocate_visits;
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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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// 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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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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: options_(options), input_objects_(input_objects), symtab_(symtab),
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target_(target), layout_(layout), mapfile_(mapfile)
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// Run the operation.
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run(Workqueue*, const Task*);
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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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// 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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// 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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// The section index.
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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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// 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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: 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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gold_assert(!k.is_comdat_);
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this->u_.linkonce_size = 0;
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if (this->is_comdat_)
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delete this->u_.group_sections;
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// The object where this section lives.
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{ return this->object_; }
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set_object(Relobj* object)
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gold_assert(this->object_ == NULL);
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this->object_ = object;
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// The section index.
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{ return this->shndx_; }
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// Set the section index.
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set_shndx(unsigned int shndx)
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gold_assert(this->shndx_ == 0);
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this->shndx_ = shndx;
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// Whether this is a comdat group.
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{ return this->is_comdat_; }
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// Set that this is a comdat group.
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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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// 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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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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{ this->is_group_name_ = true; }
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// Add a section to the group list.
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add_comdat_section(const std::string& name, unsigned int shndx,
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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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// 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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find_comdat_section(const std::string& name, unsigned int* pshndx,
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uint64_t* psize) const
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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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*pshndx = p->second.shndx;
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*psize = p->second.size;
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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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find_single_comdat_section(unsigned int* pshndx, uint64_t* psize) const
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gold_assert(this->is_comdat_);
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if (this->u_.group_sections->size() != 1)
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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 the size of a linkonce section.
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linkonce_size() const
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gold_assert(!this->is_comdat_);
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return this->u_.linkonce_size;
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// Set the size of a linkonce section.
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set_linkonce_size(uint64_t size)
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gold_assert(!this->is_comdat_);
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this->u_.linkonce_size = size;
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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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// Index of the group section for comdats and the section itself for
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// True if this is for a comdat group rather than a .gnu.linkonce
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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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// 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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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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uint64_t linkonce_size;
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// The ordering for output sections. This controls how output
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// sections are ordered within a PT_LOAD output segment.
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enum Output_section_order
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// Unspecified. Used for non-load segments. Also used for the file
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// and segment headers.
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// The PT_INTERP section should come first, so that the dynamic
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// linker can pick it up quickly.
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// Loadable read-only note sections come next so that the PT_NOTE
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// segment is on the first page of the executable.
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// Put read-only sections used by the dynamic linker early in the
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// executable to minimize paging.
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ORDER_DYNAMIC_LINKER,
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// Put reloc sections used by the dynamic linker after other
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// sections used by the dynamic linker; otherwise, objcopy and strip
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ORDER_DYNAMIC_RELOCS,
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// Put the PLT reloc section after the other dynamic relocs;
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// otherwise, prelink gets confused.
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ORDER_DYNAMIC_PLT_RELOCS,
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// The .init section.
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// The regular text sections.
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// The .fini section.
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// The read-only sections.
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// The exception frame sections.
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// The TLS sections come first in the data section.
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// Local RELRO (read-only after relocation) sections come before
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// non-local RELRO sections. This data will be fully resolved by
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// Non-local RELRO sections are grouped together after local RELRO
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// sections. All RELRO sections must be adjacent so that they can
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// all be put into a PT_GNU_RELRO segment.
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// We permit marking exactly one output section as the last RELRO
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// section. We do this so that the read-only GOT can be adjacent to
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// Similarly, we permit marking exactly one output section as the
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// first non-RELRO section.
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ORDER_NON_RELRO_FIRST,
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// The regular data sections come after the RELRO sections.
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// Large data sections normally go in large data segments.
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// Group writable notes so that we can have a single PT_NOTE
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// The small data sections must be at the end of the data sections,
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// so that they can be adjacent to the small BSS sections.
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// The BSS sections start here.
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// The small BSS sections must be at the start of the BSS sections,
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// so that they can be adjacent to the small data sections.
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// The regular BSS sections.
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// The large BSS sections come after the other BSS sections.
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// This class handles the details of laying out input sections.
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Layout(int number_of_input_files, Script_options*);
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delete this->relaxation_debug_check_;
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delete this->segment_states_;
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// For incremental links, record the base file to be modified.
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set_incremental_base(Incremental_binary* base);
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{ return this->incremental_base_; }
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// For incremental links, record the initial fixed layout of a section
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// from the base file, and return a pointer to the Output_section.
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template<int size, bool big_endian>
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init_fixed_output_section(const char*, elfcpp::Shdr<size, big_endian>&);
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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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layout(Sized_relobj_file<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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std::map<Section_id, unsigned int>*
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get_section_order_map()
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{ return &this->section_order_map_; }
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// Struct to store segment info when mapping some input sections to
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// unique segments using linker plugins. Mapping an input section to
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// a unique segment is done by first placing such input sections in
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// unique output sections and then mapping the output section to a
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// unique segment. NAME is the name of the output section. FLAGS
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// and ALIGN are the extra flags and alignment of the segment.
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struct Unique_segment_info
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// Identifier for the segment. ELF segments dont have names. This
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// is used as the name of the output section mapped to the segment.
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// Additional segment flags.
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// Segment alignment.
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// Mapping from input section to segment.
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typedef std::map<Const_section_id, Unique_segment_info*>
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// Maps section SECN to SEGMENT s.
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insert_section_segment_map(Const_section_id secn, Unique_segment_info *s);
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// Some input sections require special ordering, for compatibility
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// with GNU ld. Given the name of an input section, return -1 if it
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// does not require special ordering. Otherwise, return the index
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// by which it should be ordered compared to other input sections
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// that require special ordering.
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special_ordering_of_input_section(const char* name);
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is_section_ordering_specified()
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{ return this->section_ordering_specified_; }
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set_section_ordering_specified()
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{ this->section_ordering_specified_ = true; }
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is_unique_segment_for_sections_specified() const
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{ return this->unique_segment_for_sections_specified_; }
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set_unique_segment_for_sections_specified()
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{ this->unique_segment_for_sections_specified_ = true; }
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// For incremental updates, allocate a block of memory from the
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// free list. Find a block starting at or after MINOFF.
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allocate(off_t len, uint64_t align, off_t minoff)
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{ return this->free_list_.allocate(len, align, minoff); }
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find_section_order_index(const std::string&);
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// Read the sequence of input sections from the file specified with
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// linker option --section-ordering-file.
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read_layout_from_file();
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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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layout_reloc(Sized_relobj_file<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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layout_group(Symbol_table* symtab,
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Sized_relobj_file<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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layout_eh_frame(Sized_relobj_file<size, big_endian>* object,
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const unsigned char* symbols,
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const unsigned char* symbol_names,
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off_t symbol_names_size,
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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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// Add .eh_frame information for a PLT. The FDE must start with a
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// 4-byte PC-relative reference to the start of the PLT, followed by
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// a 4-byte size of PLT.
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add_eh_frame_for_plt(Output_data* plt, const unsigned char* cie_data,
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size_t cie_length, const unsigned char* fde_data,
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// Scan a .debug_info or .debug_types section, and add summary
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// information to the .gdb_index section.
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template<int size, bool big_endian>
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add_to_gdb_index(bool is_type_unit,
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Sized_relobj<size, big_endian>* object,
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const unsigned char* symbols,
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unsigned int reloc_shndx,
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unsigned int reloc_type);
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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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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. ORDER is where the
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// section should wind up in the output segment. IS_RELRO is true
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// for relro sections.
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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*, Output_section_order order,
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// Increase the size of the relro segment by this much.
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increase_relro(unsigned int s)
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{ this->increase_relro_ += s; }
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// Create dynamic sections if necessary.
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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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define_section_symbols(Symbol_table*);
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// Create automatic note sections.
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// Create sections for linker scripts.
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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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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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define_group_signatures(Symbol_table*);
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// Return the Stringpool used for symbol names.
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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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{ return &this->dynpool_; }
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// Return the .dynamic output section. This is only valid after the
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// layout has been finalized.
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dynamic_section() const
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{ return this->dynamic_section_; }
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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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is_linkonce(const char* name)
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{ return strncmp(name, ".gnu.linkonce", sizeof(".gnu.linkonce") - 1) == 0; }
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// Whether we have added an input section.
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have_added_input_section() const
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{ return this->have_added_input_section_; }
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// Return true if a section is a debugging section.
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is_debug_info_section(const char* name)
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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, ".zdebug", sizeof(".zdebug") - 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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// Return true if RELOBJ is an input file whose base name matches
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// FILE_NAME. The base name must have an extension of ".o", and
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// must be exactly FILE_NAME.o or FILE_NAME, one character, ".o".
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match_file_name(const Relobj* relobj, const char* file_name);
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// Return whether section SHNDX in RELOBJ is a .ctors/.dtors section
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// with more than one word being mapped to a .init_array/.fini_array
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is_ctors_in_init_array(Relobj* relobj, unsigned int shndx) const;
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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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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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finalize(const Input_objects*, Symbol_table*, Target*, const Task*);
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// Return whether any sections require postprocessing.
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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.
796
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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{ return this->tls_segment_; }
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// Return the normal symbol table.
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symtab_section() const
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gold_assert(this->symtab_section_ != NULL);
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return this->symtab_section_;
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// Return the file offset of the normal symbol table.
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symtab_section_offset() const;
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// Return the section index of the normal symbol tabl.e
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symtab_section_shndx() const;
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// Return the dynamic symbol table.
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dynsym_section() const
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gold_assert(this->dynsym_section_ != NULL);
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return this->dynsym_section_;
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// Return the dynamic tags.
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{ return this->dynamic_data_; }
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// Write out the output sections.
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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
841
write_data(const Symbol_table*, Output_file*) const;
843
// Write out output sections which can not be written until all the
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// input sections are complete.
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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.
850
find_output_section(const char* name) const;
852
// Return an output segment of type TYPE, with segment flags SET set
853
// and segment flags CLEAR clear. Return NULL if there is none.
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find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
856
elfcpp::Elf_Word clear) const;
858
// Return the number of segments we expect to produce.
860
expected_segment_count() const;
862
// Set a flag to indicate that an object file uses the static TLS model.
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{ this->has_static_tls_ = true; }
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// Return true if any object file uses the static TLS model.
869
has_static_tls() const
870
{ return this->has_static_tls_; }
872
// Return the options which may be set by a linker script.
875
{ return this->script_options_; }
877
const Script_options*
878
script_options() const
879
{ return this->script_options_; }
881
// Return the object managing inputs in incremental build. NULL in
882
// non-incremental builds.
884
incremental_inputs() const
885
{ return this->incremental_inputs_; }
887
// For the target-specific code to add dynamic tags which are common
890
add_target_dynamic_tags(bool use_rel, const Output_data* plt_got,
891
const Output_data* plt_rel,
892
const Output_data_reloc_generic* dyn_rel,
893
bool add_debug, bool dynrel_includes_plt);
895
// If a treehash is necessary to compute the build ID, then queue
896
// the necessary tasks and return a blocker that will unblock when
897
// they finish. Otherwise return BUILD_ID_BLOCKER.
899
queue_build_id_tasks(Workqueue* workqueue, Task_token* build_id_blocker,
902
// Compute and write out the build ID if needed.
904
write_build_id(Output_file*) const;
906
// Rewrite output file in binary format.
908
write_binary(Output_file* in) const;
910
// Print output sections to the map file.
912
print_to_mapfile(Mapfile*) const;
914
// Dump statistical information to stderr.
918
// A list of segments.
920
typedef std::vector<Output_segment*> Segment_list;
922
// A list of sections.
924
typedef std::vector<Output_section*> Section_list;
926
// The list of information to write out which is not attached to
927
// either a section or a segment.
928
typedef std::vector<Output_data*> Data_list;
930
// Store the allocated sections into the section list. This is used
931
// by the linker script code.
933
get_allocated_sections(Section_list*) const;
935
// Store the executable sections into the section list.
937
get_executable_sections(Section_list*) const;
939
// Make a section for a linker script to hold data.
941
make_output_section_for_script(const char* name,
942
Script_sections::Section_type section_type);
944
// Make a segment. This is used by the linker script code.
946
make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags);
948
// Return the number of segments.
950
segment_count() const
951
{ return this->segment_list_.size(); }
953
// Map from section flags to segment flags.
954
static elfcpp::Elf_Word
955
section_flags_to_segment(elfcpp::Elf_Xword flags);
957
// Attach sections to segments.
959
attach_sections_to_segments(const Target*);
961
// For relaxation clean up, we need to know output section data created
962
// from a linker script.
964
new_output_section_data_from_script(Output_section_data* posd)
966
if (this->record_output_section_data_from_script_)
967
this->script_output_section_data_list_.push_back(posd);
970
// Return section list.
973
{ return this->section_list_; }
975
// Returns TRUE iff NAME (an input section from RELOBJ) will
976
// be mapped to an output section that should be KEPT.
978
keep_input_section(const Relobj*, const char*);
981
Layout(const Layout&);
982
Layout& operator=(const Layout&);
984
// Mapping from input section names to output section names.
985
struct Section_name_mapping
992
static const Section_name_mapping section_name_mapping[];
993
static const int section_name_mapping_count;
995
// During a relocatable link, a list of group sections and
997
struct Group_signature
999
// The group section.
1000
Output_section* section;
1002
const char* signature;
1005
: section(NULL), signature(NULL)
1008
Group_signature(Output_section* sectiona, const char* signaturea)
1009
: section(sectiona), signature(signaturea)
1012
typedef std::vector<Group_signature> Group_signatures;
1014
// Create a note section, filling in the header.
1016
create_note(const char* name, int note_type, const char* section_name,
1017
size_t descsz, bool allocate, size_t* trailing_padding);
1019
// Create a note section for gold version.
1023
// Record whether the stack must be executable.
1025
create_executable_stack_info();
1027
// Create a build ID note if needed.
1031
// Link .stab and .stabstr sections.
1033
link_stabs_sections();
1035
// Create .gnu_incremental_inputs and .gnu_incremental_strtab sections needed
1036
// for the next run of incremental linking to check what has changed.
1038
create_incremental_info_sections(Symbol_table*);
1040
// Find the first read-only PT_LOAD segment, creating one if
1043
find_first_load_seg(const Target*);
1045
// Count the local symbols in the regular symbol table and the dynamic
1046
// symbol table, and build the respective string pools.
1048
count_local_symbols(const Task*, const Input_objects*);
1050
// Create the output sections for the symbol table.
1052
create_symtab_sections(const Input_objects*, Symbol_table*,
1053
unsigned int, off_t*);
1055
// Create the .shstrtab section.
1059
// Create the section header table.
1061
create_shdrs(const Output_section* shstrtab_section, off_t*);
1063
// Create the dynamic symbol table.
1065
create_dynamic_symtab(const Input_objects*, Symbol_table*,
1066
Output_section** pdynstr,
1067
unsigned int* plocal_dynamic_count,
1068
std::vector<Symbol*>* pdynamic_symbols,
1069
Versions* versions);
1071
// Assign offsets to each local portion of the dynamic symbol table.
1073
assign_local_dynsym_offsets(const Input_objects*);
1075
// Finish the .dynamic section and PT_DYNAMIC segment.
1077
finish_dynamic_section(const Input_objects*, const Symbol_table*);
1079
// Set the size of the _DYNAMIC symbol.
1081
set_dynamic_symbol_size(const Symbol_table*);
1083
// Create the .interp section and PT_INTERP segment.
1085
create_interp(const Target* target);
1087
// Create the version sections.
1089
create_version_sections(const Versions*,
1090
const Symbol_table*,
1091
unsigned int local_symcount,
1092
const std::vector<Symbol*>& dynamic_symbols,
1093
const Output_section* dynstr);
1095
template<int size, bool big_endian>
1097
sized_create_version_sections(const Versions* versions,
1098
const Symbol_table*,
1099
unsigned int local_symcount,
1100
const std::vector<Symbol*>& dynamic_symbols,
1101
const Output_section* dynstr);
1103
// Return whether to include this section in the link.
1104
template<int size, bool big_endian>
1106
include_section(Sized_relobj_file<size, big_endian>* object, const char* name,
1107
const elfcpp::Shdr<size, big_endian>&);
1109
// Return the output section name to use given an input section
1110
// name. Set *PLEN to the length of the name. *PLEN must be
1111
// initialized to the length of NAME.
1113
output_section_name(const Relobj*, const char* name, size_t* plen);
1115
// Return the number of allocated output sections.
1117
allocated_output_section_count() const;
1119
// Return the output section for NAME, TYPE and FLAGS.
1121
get_output_section(const char* name, Stringpool::Key name_key,
1122
elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
1123
Output_section_order order, bool is_relro);
1125
// Clear the input section flags that should not be copied to the
1128
get_output_section_flags (elfcpp::Elf_Xword input_section_flags);
1130
// Choose the output section for NAME in RELOBJ.
1132
choose_output_section(const Relobj* relobj, const char* name,
1133
elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
1134
bool is_input_section, Output_section_order order,
1137
// Create a new Output_section.
1139
make_output_section(const char* name, elfcpp::Elf_Word type,
1140
elfcpp::Elf_Xword flags, Output_section_order order,
1143
// Attach a section to a segment.
1145
attach_section_to_segment(const Target*, Output_section*);
1147
// Get section order.
1148
Output_section_order
1149
default_section_order(Output_section*, bool is_relro_local);
1151
// Attach an allocated section to a segment.
1153
attach_allocated_section_to_segment(const Target*, Output_section*);
1155
// Make the .eh_frame section.
1157
make_eh_frame_section(const Relobj*);
1159
// Set the final file offsets of all the segments.
1161
set_segment_offsets(const Target*, Output_segment*, unsigned int* pshndx);
1163
// Set the file offsets of the sections when doing a relocatable
1166
set_relocatable_section_offsets(Output_data*, unsigned int* pshndx);
1168
// Set the final file offsets of all the sections not associated
1169
// with a segment. We set section offsets in three passes: the
1170
// first handles all allocated sections, the second sections that
1171
// require postprocessing, and the last the late-bound STRTAB
1172
// sections (probably only shstrtab, which is the one we care about
1173
// because it holds section names).
1174
enum Section_offset_pass
1176
BEFORE_INPUT_SECTIONS_PASS,
1177
POSTPROCESSING_SECTIONS_PASS,
1178
STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
1181
set_section_offsets(off_t, Section_offset_pass pass);
1183
// Set the final section indexes of all the sections not associated
1184
// with a segment. Returns the next unused index.
1186
set_section_indexes(unsigned int pshndx);
1188
// Set the section addresses when using a script.
1190
set_section_addresses_from_script(Symbol_table*);
1192
// Find appropriate places or orphan sections in a script.
1194
place_orphan_sections_in_script();
1196
// Return whether SEG1 comes before SEG2 in the output file.
1198
segment_precedes(const Output_segment* seg1, const Output_segment* seg2);
1200
// Use to save and restore segments during relaxation.
1201
typedef Unordered_map<const Output_segment*, const Output_segment*>
1204
// Save states of current output segments.
1206
save_segments(Segment_states*);
1208
// Restore output segment states.
1210
restore_segments(const Segment_states*);
1212
// Clean up after relaxation so that it is possible to lay out the
1213
// sections and segments again.
1215
clean_up_after_relaxation();
1217
// Doing preparation work for relaxation. This is factored out to make
1218
// Layout::finalized a bit smaller and easier to read.
1220
prepare_for_relaxation();
1222
// Main body of the relaxation loop, which lays out the section.
1224
relaxation_loop_body(int, Target*, Symbol_table*, Output_segment**,
1225
Output_segment*, Output_segment_headers*,
1226
Output_file_header*, unsigned int*);
1228
// A mapping used for kept comdats/.gnu.linkonce group signatures.
1229
typedef Unordered_map<std::string, Kept_section> Signatures;
1231
// Mapping from input section name/type/flags to output section. We
1232
// use canonicalized strings here.
1234
typedef std::pair<Stringpool::Key,
1235
std::pair<elfcpp::Elf_Word, elfcpp::Elf_Xword> > Key;
1240
operator()(const Key& k) const;
1243
typedef Unordered_map<Key, Output_section*, Hash_key> Section_name_map;
1245
// A comparison class for segments.
1247
class Compare_segments
1250
Compare_segments(Layout* layout)
1255
operator()(const Output_segment* seg1, const Output_segment* seg2)
1256
{ return this->layout_->segment_precedes(seg1, seg2); }
1262
typedef std::vector<Output_section_data*> Output_section_data_list;
1264
// Debug checker class.
1265
class Relaxation_debug_check
1268
Relaxation_debug_check()
1272
// Check that sections and special data are in reset states.
1274
check_output_data_for_reset_values(const Layout::Section_list&,
1275
const Layout::Data_list&);
1277
// Record information of a section list.
1279
read_sections(const Layout::Section_list&);
1281
// Verify a section list with recorded information.
1283
verify_sections(const Layout::Section_list&);
1286
// Information we care about a section.
1289
// Output section described by this.
1290
Output_section* output_section;
1299
// Section information.
1300
std::vector<Section_info> section_infos_;
1303
// The number of input files, for sizing tables.
1304
int number_of_input_files_;
1305
// Information set by scripts or by command line options.
1306
Script_options* script_options_;
1307
// The output section names.
1308
Stringpool namepool_;
1309
// The output symbol names.
1310
Stringpool sympool_;
1311
// The dynamic strings, if needed.
1312
Stringpool dynpool_;
1313
// The list of group sections and linkonce sections which we have seen.
1314
Signatures signatures_;
1315
// The mapping from input section name/type/flags to output sections.
1316
Section_name_map section_name_map_;
1317
// The list of output segments.
1318
Segment_list segment_list_;
1319
// The list of output sections.
1320
Section_list section_list_;
1321
// The list of output sections which are not attached to any output
1323
Section_list unattached_section_list_;
1324
// The list of unattached Output_data objects which require special
1325
// handling because they are not Output_sections.
1326
Data_list special_output_list_;
1327
// The section headers.
1328
Output_section_headers* section_headers_;
1329
// A pointer to the PT_TLS segment if there is one.
1330
Output_segment* tls_segment_;
1331
// A pointer to the PT_GNU_RELRO segment if there is one.
1332
Output_segment* relro_segment_;
1333
// A pointer to the PT_INTERP segment if there is one.
1334
Output_segment* interp_segment_;
1335
// A backend may increase the size of the PT_GNU_RELRO segment if
1336
// there is one. This is the amount to increase it by.
1337
unsigned int increase_relro_;
1338
// The SHT_SYMTAB output section.
1339
Output_section* symtab_section_;
1340
// The SHT_SYMTAB_SHNDX for the regular symbol table if there is one.
1341
Output_symtab_xindex* symtab_xindex_;
1342
// The SHT_DYNSYM output section if there is one.
1343
Output_section* dynsym_section_;
1344
// The SHT_SYMTAB_SHNDX for the dynamic symbol table if there is one.
1345
Output_symtab_xindex* dynsym_xindex_;
1346
// The SHT_DYNAMIC output section if there is one.
1347
Output_section* dynamic_section_;
1348
// The _DYNAMIC symbol if there is one.
1349
Symbol* dynamic_symbol_;
1350
// The dynamic data which goes into dynamic_section_.
1351
Output_data_dynamic* dynamic_data_;
1352
// The exception frame output section if there is one.
1353
Output_section* eh_frame_section_;
1354
// The exception frame data for eh_frame_section_.
1355
Eh_frame* eh_frame_data_;
1356
// Whether we have added eh_frame_data_ to the .eh_frame section.
1357
bool added_eh_frame_data_;
1358
// The exception frame header output section if there is one.
1359
Output_section* eh_frame_hdr_section_;
1360
// The data for the .gdb_index section.
1361
Gdb_index* gdb_index_data_;
1362
// The space for the build ID checksum if there is one.
1363
Output_section_data* build_id_note_;
1364
// Temporary storage for tree hash of build ID.
1365
unsigned char* array_of_hashes_;
1366
// Size of array_of_hashes_ (in bytes).
1367
size_t size_of_array_of_hashes_;
1368
// Input view for computing tree hash of build ID. Freed in write_build_id().
1369
const unsigned char* input_view_;
1370
// The output section containing dwarf abbreviations
1371
Output_reduced_debug_abbrev_section* debug_abbrev_;
1372
// The output section containing the dwarf debug info tree
1373
Output_reduced_debug_info_section* debug_info_;
1374
// A list of group sections and their signatures.
1375
Group_signatures group_signatures_;
1376
// The size of the output file.
1377
off_t output_file_size_;
1378
// Whether we have added an input section to an output section.
1379
bool have_added_input_section_;
1380
// Whether we have attached the sections to the segments.
1381
bool sections_are_attached_;
1382
// Whether we have seen an object file marked to require an
1383
// executable stack.
1384
bool input_requires_executable_stack_;
1385
// Whether we have seen at least one object file with an executable
1387
bool input_with_gnu_stack_note_;
1388
// Whether we have seen at least one object file without an
1389
// executable stack marker.
1390
bool input_without_gnu_stack_note_;
1391
// Whether we have seen an object file that uses the static TLS model.
1392
bool has_static_tls_;
1393
// Whether any sections require postprocessing.
1394
bool any_postprocessing_sections_;
1395
// Whether we have resized the signatures_ hash table.
1396
bool resized_signatures_;
1397
// Whether we have created a .stab*str output section.
1398
bool have_stabstr_section_;
1399
// True if the input sections in the output sections should be sorted
1400
// as specified in a section ordering file.
1401
bool section_ordering_specified_;
1402
// True if some input sections need to be mapped to a unique segment,
1403
// after being mapped to a unique Output_section.
1404
bool unique_segment_for_sections_specified_;
1405
// In incremental build, holds information check the inputs and build the
1406
// .gnu_incremental_inputs section.
1407
Incremental_inputs* incremental_inputs_;
1408
// Whether we record output section data created in script
1409
bool record_output_section_data_from_script_;
1410
// List of output data that needs to be removed at relaxation clean up.
1411
Output_section_data_list script_output_section_data_list_;
1412
// Structure to save segment states before entering the relaxation loop.
1413
Segment_states* segment_states_;
1414
// A relaxation debug checker. We only create one when in debugging mode.
1415
Relaxation_debug_check* relaxation_debug_check_;
1416
// Plugins specify section_ordering using this map. This is set in
1417
// update_section_order in plugin.cc
1418
std::map<Section_id, unsigned int> section_order_map_;
1419
// This maps an input section to a unique segment. This is done by first
1420
// placing such input sections in unique output sections and then mapping
1421
// the output section to a unique segment. Unique_segment_info stores
1422
// any additional flags and alignment of the new segment.
1423
Section_segment_map section_segment_map_;
1424
// Hash a pattern to its position in the section ordering file.
1425
Unordered_map<std::string, unsigned int> input_section_position_;
1426
// Vector of glob only patterns in the section_ordering file.
1427
std::vector<std::string> input_section_glob_;
1428
// For incremental links, the base file to be modified.
1429
Incremental_binary* incremental_base_;
1430
// For incremental links, a list of free space within the file.
1431
Free_list free_list_;
1434
// This task handles writing out data in output sections which is not
1435
// part of an input section, or which requires special handling. When
1436
// this is done, it unblocks both output_sections_blocker and
1439
class Write_sections_task : public Task
1442
Write_sections_task(const Layout* layout, Output_file* of,
1443
Task_token* output_sections_blocker,
1444
Task_token* final_blocker)
1445
: layout_(layout), of_(of),
1446
output_sections_blocker_(output_sections_blocker),
1447
final_blocker_(final_blocker)
1450
// The standard Task methods.
1456
locks(Task_locker*);
1463
{ return "Write_sections_task"; }
1466
class Write_sections_locker;
1468
const Layout* layout_;
1470
Task_token* output_sections_blocker_;
1471
Task_token* final_blocker_;
1474
// This task handles writing out data which is not part of a section
1477
class Write_data_task : public Task
1480
Write_data_task(const Layout* layout, const Symbol_table* symtab,
1481
Output_file* of, Task_token* final_blocker)
1482
: layout_(layout), symtab_(symtab), of_(of), final_blocker_(final_blocker)
1485
// The standard Task methods.
1491
locks(Task_locker*);
1498
{ return "Write_data_task"; }
1501
const Layout* layout_;
1502
const Symbol_table* symtab_;
1504
Task_token* final_blocker_;
1507
// This task handles writing out the global symbols.
1509
class Write_symbols_task : public Task
1512
Write_symbols_task(const Layout* layout, const Symbol_table* symtab,
1513
const Input_objects* input_objects,
1514
const Stringpool* sympool, const Stringpool* dynpool,
1515
Output_file* of, Task_token* final_blocker)
1516
: layout_(layout), symtab_(symtab), input_objects_(input_objects),
1517
sympool_(sympool), dynpool_(dynpool), of_(of),
1518
final_blocker_(final_blocker)
1521
// The standard Task methods.
1527
locks(Task_locker*);
1534
{ return "Write_symbols_task"; }
1537
const Layout* layout_;
1538
const Symbol_table* symtab_;
1539
const Input_objects* input_objects_;
1540
const Stringpool* sympool_;
1541
const Stringpool* dynpool_;
1543
Task_token* final_blocker_;
1546
// This task handles writing out data in output sections which can't
1547
// be written out until all the input sections have been handled.
1548
// This is for sections whose contents is based on the contents of
1549
// other output sections.
1551
class Write_after_input_sections_task : public Task
1554
Write_after_input_sections_task(Layout* layout, Output_file* of,
1555
Task_token* input_sections_blocker,
1556
Task_token* final_blocker)
1557
: layout_(layout), of_(of),
1558
input_sections_blocker_(input_sections_blocker),
1559
final_blocker_(final_blocker)
1562
// The standard Task methods.
1568
locks(Task_locker*);
1575
{ return "Write_after_input_sections_task"; }
1580
Task_token* input_sections_blocker_;
1581
Task_token* final_blocker_;
1584
// This task function handles closing the file.
1586
class Close_task_runner : public Task_function_runner
1589
Close_task_runner(const General_options* options, const Layout* layout,
1591
: options_(options), layout_(layout), of_(of)
1594
// Run the operation.
1596
run(Workqueue*, const Task*);
1599
const General_options* options_;
1600
const Layout* layout_;
1604
// A small helper function to align an address.
1607
align_address(uint64_t address, uint64_t addralign)
1610
address = (address + addralign - 1) &~ (addralign - 1);
1614
} // End namespace gold.
1616
#endif // !defined(GOLD_LAYOUT_H)
added
removed
binutils-2.23.52.20130611/gold/layout.h
