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1728 lines
50 KiB
C++
1728 lines
50 KiB
C++
// layout.cc -- lay out output file sections for gold
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// Copyright 2006, 2007 Free Software Foundation, Inc.
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// Written by Ian Lance Taylor <iant@google.com>.
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// This file is part of gold.
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 3 of the License, or
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// (at your option) any later version.
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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// MA 02110-1301, USA.
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#include "gold.h"
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#include <cstring>
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#include <algorithm>
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#include <iostream>
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#include <utility>
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#include "parameters.h"
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#include "output.h"
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#include "symtab.h"
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#include "dynobj.h"
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#include "ehframe.h"
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#include "layout.h"
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namespace gold
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{
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// Layout_task_runner methods.
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// Lay out the sections. This is called after all the input objects
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// have been read.
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void
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Layout_task_runner::run(Workqueue* workqueue)
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{
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off_t file_size = this->layout_->finalize(this->input_objects_,
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this->symtab_);
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// Now we know the final size of the output file and we know where
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// each piece of information goes.
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Output_file* of = new Output_file(this->options_,
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this->input_objects_->target());
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of->open(file_size);
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// Queue up the final set of tasks.
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gold::queue_final_tasks(this->options_, this->input_objects_,
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this->symtab_, this->layout_, workqueue, of);
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}
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// Layout methods.
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Layout::Layout(const General_options& options)
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: options_(options), namepool_(), sympool_(), dynpool_(), signatures_(),
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section_name_map_(), segment_list_(), section_list_(),
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unattached_section_list_(), special_output_list_(),
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tls_segment_(NULL), symtab_section_(NULL),
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dynsym_section_(NULL), dynamic_section_(NULL), dynamic_data_(NULL),
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eh_frame_section_(NULL)
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{
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// Make space for more than enough segments for a typical file.
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// This is just for efficiency--it's OK if we wind up needing more.
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this->segment_list_.reserve(12);
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// We expect three unattached Output_data objects: the file header,
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// the segment headers, and the section headers.
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this->special_output_list_.reserve(3);
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}
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// Hash a key we use to look up an output section mapping.
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size_t
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Layout::Hash_key::operator()(const Layout::Key& k) const
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{
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return k.first + k.second.first + k.second.second;
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}
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// Return whether PREFIX is a prefix of STR.
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static inline bool
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is_prefix_of(const char* prefix, const char* str)
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{
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return strncmp(prefix, str, strlen(prefix)) == 0;
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}
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// Whether to include this section in the link.
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template<int size, bool big_endian>
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bool
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Layout::include_section(Object*, const char* name,
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const elfcpp::Shdr<size, big_endian>& shdr)
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{
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// Some section types are never linked. Some are only linked when
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// doing a relocateable link.
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switch (shdr.get_sh_type())
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{
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case elfcpp::SHT_NULL:
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case elfcpp::SHT_SYMTAB:
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case elfcpp::SHT_DYNSYM:
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case elfcpp::SHT_STRTAB:
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case elfcpp::SHT_HASH:
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case elfcpp::SHT_DYNAMIC:
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case elfcpp::SHT_SYMTAB_SHNDX:
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return false;
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case elfcpp::SHT_RELA:
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case elfcpp::SHT_REL:
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case elfcpp::SHT_GROUP:
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return parameters->output_is_object();
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case elfcpp::SHT_PROGBITS:
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if (parameters->strip_debug()
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&& (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
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{
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// Debugging sections can only be recognized by name.
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if (is_prefix_of(".debug", name)
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|| is_prefix_of(".gnu.linkonce.wi.", name)
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|| is_prefix_of(".line", name)
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|| is_prefix_of(".stab", name))
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return false;
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}
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return true;
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default:
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return true;
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}
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}
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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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Layout::find_output_section(const char* name) const
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{
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for (Section_name_map::const_iterator p = this->section_name_map_.begin();
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p != this->section_name_map_.end();
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++p)
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if (strcmp(p->second->name(), name) == 0)
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return p->second;
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return NULL;
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}
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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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Layout::find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
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elfcpp::Elf_Word clear) const
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{
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for (Segment_list::const_iterator p = this->segment_list_.begin();
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p != this->segment_list_.end();
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++p)
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if (static_cast<elfcpp::PT>((*p)->type()) == type
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&& ((*p)->flags() & set) == set
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&& ((*p)->flags() & clear) == 0)
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return *p;
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return NULL;
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}
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// Return the output section to use for section NAME with type TYPE
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// and section flags FLAGS.
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Output_section*
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Layout::get_output_section(const char* name, Stringpool::Key name_key,
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elfcpp::Elf_Word type, elfcpp::Elf_Xword flags)
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{
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// We should ignore some flags.
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flags &= ~ (elfcpp::SHF_INFO_LINK
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| elfcpp::SHF_LINK_ORDER
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| elfcpp::SHF_GROUP
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| elfcpp::SHF_MERGE
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| elfcpp::SHF_STRINGS);
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const Key key(name_key, std::make_pair(type, flags));
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const std::pair<Key, Output_section*> v(key, NULL);
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std::pair<Section_name_map::iterator, bool> ins(
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this->section_name_map_.insert(v));
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if (!ins.second)
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return ins.first->second;
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else
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{
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// This is the first time we've seen this name/type/flags
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// combination.
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Output_section* os = this->make_output_section(name, type, flags);
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ins.first->second = os;
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return os;
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}
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}
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// Return the output section to use for input section SHNDX, with name
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// NAME, with header HEADER, from object OBJECT. Set *OFF to the
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// offset of this input section without the output section.
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template<int size, bool big_endian>
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Output_section*
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Layout::layout(Relobj* object, unsigned int shndx, const char* name,
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const elfcpp::Shdr<size, big_endian>& shdr, off_t* off)
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{
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if (!this->include_section(object, name, shdr))
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return NULL;
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// If we are not doing a relocateable link, choose the name to use
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// for the output section.
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size_t len = strlen(name);
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if (!parameters->output_is_object())
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name = Layout::output_section_name(name, &len);
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// FIXME: Handle SHF_OS_NONCONFORMING here.
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// Canonicalize the section name.
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Stringpool::Key name_key;
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name = this->namepool_.add(name, len, &name_key);
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// Find the output section. The output section is selected based on
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// the section name, type, and flags.
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Output_section* os = this->get_output_section(name, name_key,
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shdr.get_sh_type(),
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shdr.get_sh_flags());
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// Special GNU handling of sections named .eh_frame.
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if (!parameters->output_is_object()
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&& strcmp(name, ".eh_frame") == 0
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&& shdr.get_sh_size() > 0
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&& shdr.get_sh_type() == elfcpp::SHT_PROGBITS
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&& shdr.get_sh_flags() == elfcpp::SHF_ALLOC)
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{
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this->layout_eh_frame(object, shndx, name, shdr, os, off);
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return os;
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}
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// FIXME: Handle SHF_LINK_ORDER somewhere.
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*off = os->add_input_section(object, shndx, name, shdr);
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return os;
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}
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// Special GNU handling of sections named .eh_frame. They will
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// normally hold exception frame data.
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template<int size, bool big_endian>
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void
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Layout::layout_eh_frame(Relobj* object,
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unsigned int shndx,
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const char* name,
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const elfcpp::Shdr<size, big_endian>& shdr,
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Output_section* os, off_t* off)
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{
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if (this->eh_frame_section_ == NULL)
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{
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this->eh_frame_section_ = os;
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if (this->options_.create_eh_frame_hdr())
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{
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Stringpool::Key hdr_name_key;
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const char* hdr_name = this->namepool_.add(".eh_frame_hdr",
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&hdr_name_key);
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Output_section* hdr_os =
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this->get_output_section(hdr_name, hdr_name_key,
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elfcpp::SHT_PROGBITS,
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elfcpp::SHF_ALLOC);
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Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os);
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hdr_os->add_output_section_data(hdr_posd);
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Output_segment* hdr_oseg =
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new Output_segment(elfcpp::PT_GNU_EH_FRAME, elfcpp::PF_R);
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this->segment_list_.push_back(hdr_oseg);
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hdr_oseg->add_output_section(hdr_os, elfcpp::PF_R);
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}
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}
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gold_assert(this->eh_frame_section_ == os);
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*off = os->add_input_section(object, shndx, name, shdr);
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}
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// Add POSD to an output section using NAME, TYPE, and FLAGS.
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void
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Layout::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* posd)
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{
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// Canonicalize the name.
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Stringpool::Key name_key;
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name = this->namepool_.add(name, &name_key);
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Output_section* os = this->get_output_section(name, name_key, type, flags);
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os->add_output_section_data(posd);
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}
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// Map section flags to segment flags.
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elfcpp::Elf_Word
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Layout::section_flags_to_segment(elfcpp::Elf_Xword flags)
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{
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elfcpp::Elf_Word ret = elfcpp::PF_R;
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if ((flags & elfcpp::SHF_WRITE) != 0)
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ret |= elfcpp::PF_W;
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if ((flags & elfcpp::SHF_EXECINSTR) != 0)
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ret |= elfcpp::PF_X;
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return ret;
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}
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// Make a new Output_section, and attach it to segments as
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// appropriate.
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Output_section*
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Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
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elfcpp::Elf_Xword flags)
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{
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Output_section* os = new Output_section(name, type, flags);
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this->section_list_.push_back(os);
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if ((flags & elfcpp::SHF_ALLOC) == 0)
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this->unattached_section_list_.push_back(os);
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else
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{
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// This output section goes into a PT_LOAD segment.
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elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);
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// The only thing we really care about for PT_LOAD segments is
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// whether or not they are writable, so that is how we search
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// for them. People who need segments sorted on some other
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// basis will have to wait until we implement a mechanism for
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// them to describe the segments they want.
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Segment_list::const_iterator p;
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for (p = this->segment_list_.begin();
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p != this->segment_list_.end();
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++p)
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{
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if ((*p)->type() == elfcpp::PT_LOAD
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&& ((*p)->flags() & elfcpp::PF_W) == (seg_flags & elfcpp::PF_W))
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{
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(*p)->add_output_section(os, seg_flags);
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break;
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}
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}
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if (p == this->segment_list_.end())
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{
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Output_segment* oseg = new Output_segment(elfcpp::PT_LOAD,
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seg_flags);
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this->segment_list_.push_back(oseg);
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oseg->add_output_section(os, seg_flags);
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}
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// If we see a loadable SHT_NOTE section, we create a PT_NOTE
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// segment.
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if (type == elfcpp::SHT_NOTE)
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{
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// See if we already have an equivalent PT_NOTE segment.
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for (p = this->segment_list_.begin();
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p != segment_list_.end();
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++p)
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{
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if ((*p)->type() == elfcpp::PT_NOTE
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&& (((*p)->flags() & elfcpp::PF_W)
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== (seg_flags & elfcpp::PF_W)))
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{
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(*p)->add_output_section(os, seg_flags);
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break;
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}
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}
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if (p == this->segment_list_.end())
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{
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Output_segment* oseg = new Output_segment(elfcpp::PT_NOTE,
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seg_flags);
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this->segment_list_.push_back(oseg);
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oseg->add_output_section(os, seg_flags);
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}
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}
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// If we see a loadable SHF_TLS section, we create a PT_TLS
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// segment. There can only be one such segment.
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if ((flags & elfcpp::SHF_TLS) != 0)
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{
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if (this->tls_segment_ == NULL)
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{
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this->tls_segment_ = new Output_segment(elfcpp::PT_TLS,
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seg_flags);
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this->segment_list_.push_back(this->tls_segment_);
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}
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this->tls_segment_->add_output_section(os, seg_flags);
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}
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}
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return os;
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}
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// Create the dynamic sections which are needed before we read the
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// relocs.
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void
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Layout::create_initial_dynamic_sections(const Input_objects* input_objects,
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Symbol_table* symtab)
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{
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if (!input_objects->any_dynamic())
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return;
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const char* dynamic_name = this->namepool_.add(".dynamic", NULL);
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this->dynamic_section_ = this->make_output_section(dynamic_name,
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elfcpp::SHT_DYNAMIC,
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(elfcpp::SHF_ALLOC
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| elfcpp::SHF_WRITE));
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symtab->define_in_output_data(input_objects->target(), "_DYNAMIC", NULL,
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this->dynamic_section_, 0, 0,
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elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
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elfcpp::STV_HIDDEN, 0, false, false);
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this->dynamic_data_ = new Output_data_dynamic(&this->dynpool_);
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this->dynamic_section_->add_output_section_data(this->dynamic_data_);
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}
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// For each output section whose name can be represented as C symbol,
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// define __start and __stop symbols for the section. This is a GNU
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// extension.
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void
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Layout::define_section_symbols(Symbol_table* symtab, const Target* target)
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{
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for (Section_list::const_iterator p = this->section_list_.begin();
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p != this->section_list_.end();
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++p)
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{
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const char* const name = (*p)->name();
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if (name[strspn(name,
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("0123456789"
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"ABCDEFGHIJKLMNOPWRSTUVWXYZ"
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"abcdefghijklmnopqrstuvwxyz"
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"_"))]
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== '\0')
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{
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const std::string name_string(name);
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const std::string start_name("__start_" + name_string);
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const std::string stop_name("__stop_" + name_string);
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symtab->define_in_output_data(target,
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start_name.c_str(),
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NULL, // version
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*p,
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0, // value
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0, // symsize
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elfcpp::STT_NOTYPE,
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elfcpp::STB_GLOBAL,
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elfcpp::STV_DEFAULT,
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0, // nonvis
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false, // offset_is_from_end
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false); // only_if_ref
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symtab->define_in_output_data(target,
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stop_name.c_str(),
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NULL, // version
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*p,
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0, // value
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0, // symsize
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elfcpp::STT_NOTYPE,
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elfcpp::STB_GLOBAL,
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elfcpp::STV_DEFAULT,
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0, // nonvis
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true, // offset_is_from_end
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false); // only_if_ref
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}
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}
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}
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// Find the first read-only PT_LOAD segment, creating one if
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// necessary.
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Output_segment*
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Layout::find_first_load_seg()
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{
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for (Segment_list::const_iterator p = this->segment_list_.begin();
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p != this->segment_list_.end();
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++p)
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{
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if ((*p)->type() == elfcpp::PT_LOAD
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&& ((*p)->flags() & elfcpp::PF_R) != 0
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&& ((*p)->flags() & elfcpp::PF_W) == 0)
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return *p;
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}
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Output_segment* load_seg = new Output_segment(elfcpp::PT_LOAD, elfcpp::PF_R);
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this->segment_list_.push_back(load_seg);
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return load_seg;
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}
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// Finalize the layout. When this is called, we have created all the
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// output sections and all the output segments which are based on
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// input sections. We have several things to do, and we have to do
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// them in the right order, so that we get the right results correctly
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// and efficiently.
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// 1) Finalize the list of output segments and create the segment
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// table header.
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// 2) Finalize the dynamic symbol table and associated sections.
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// 3) Determine the final file offset of all the output segments.
|
|
|
|
// 4) Determine the final file offset of all the SHF_ALLOC output
|
|
// sections.
|
|
|
|
// 5) Create the symbol table sections and the section name table
|
|
// section.
|
|
|
|
// 6) Finalize the symbol table: set symbol values to their final
|
|
// value and make a final determination of which symbols are going
|
|
// into the output symbol table.
|
|
|
|
// 7) Create the section table header.
|
|
|
|
// 8) Determine the final file offset of all the output sections which
|
|
// are not SHF_ALLOC, including the section table header.
|
|
|
|
// 9) Finalize the ELF file header.
|
|
|
|
// This function returns the size of the output file.
|
|
|
|
off_t
|
|
Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab)
|
|
{
|
|
Target* const target = input_objects->target();
|
|
|
|
target->finalize_sections(this);
|
|
|
|
this->create_note_section();
|
|
|
|
Output_segment* phdr_seg = NULL;
|
|
if (input_objects->any_dynamic())
|
|
{
|
|
// There was a dynamic object in the link. We need to create
|
|
// some information for the dynamic linker.
|
|
|
|
// Create the PT_PHDR segment which will hold the program
|
|
// headers.
|
|
phdr_seg = new Output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);
|
|
this->segment_list_.push_back(phdr_seg);
|
|
|
|
// Create the dynamic symbol table, including the hash table.
|
|
Output_section* dynstr;
|
|
std::vector<Symbol*> dynamic_symbols;
|
|
unsigned int local_dynamic_count;
|
|
Versions versions;
|
|
this->create_dynamic_symtab(target, symtab, &dynstr,
|
|
&local_dynamic_count, &dynamic_symbols,
|
|
&versions);
|
|
|
|
// Create the .interp section to hold the name of the
|
|
// interpreter, and put it in a PT_INTERP segment.
|
|
this->create_interp(target);
|
|
|
|
// Finish the .dynamic section to hold the dynamic data, and put
|
|
// it in a PT_DYNAMIC segment.
|
|
this->finish_dynamic_section(input_objects, symtab);
|
|
|
|
// We should have added everything we need to the dynamic string
|
|
// table.
|
|
this->dynpool_.set_string_offsets();
|
|
|
|
// Create the version sections. We can't do this until the
|
|
// dynamic string table is complete.
|
|
this->create_version_sections(&versions, local_dynamic_count,
|
|
dynamic_symbols, dynstr);
|
|
}
|
|
|
|
// FIXME: Handle PT_GNU_STACK.
|
|
|
|
Output_segment* load_seg = this->find_first_load_seg();
|
|
|
|
// Lay out the segment headers.
|
|
Output_segment_headers* segment_headers;
|
|
segment_headers = new Output_segment_headers(this->segment_list_);
|
|
load_seg->add_initial_output_data(segment_headers);
|
|
this->special_output_list_.push_back(segment_headers);
|
|
if (phdr_seg != NULL)
|
|
phdr_seg->add_initial_output_data(segment_headers);
|
|
|
|
// Lay out the file header.
|
|
Output_file_header* file_header;
|
|
file_header = new Output_file_header(target, symtab, segment_headers);
|
|
load_seg->add_initial_output_data(file_header);
|
|
this->special_output_list_.push_back(file_header);
|
|
|
|
// We set the output section indexes in set_segment_offsets and
|
|
// set_section_offsets.
|
|
unsigned int shndx = 1;
|
|
|
|
// Set the file offsets of all the segments, and all the sections
|
|
// they contain.
|
|
off_t off = this->set_segment_offsets(target, load_seg, &shndx);
|
|
|
|
// Create the symbol table sections.
|
|
this->create_symtab_sections(input_objects, symtab, &off);
|
|
|
|
// Create the .shstrtab section.
|
|
Output_section* shstrtab_section = this->create_shstrtab();
|
|
|
|
// Set the file offsets of all the sections not associated with
|
|
// segments.
|
|
off = this->set_section_offsets(off, &shndx);
|
|
|
|
// Create the section table header.
|
|
Output_section_headers* oshdrs = this->create_shdrs(&off);
|
|
|
|
file_header->set_section_info(oshdrs, shstrtab_section);
|
|
|
|
// Now we know exactly where everything goes in the output file.
|
|
Output_data::layout_complete();
|
|
|
|
return off;
|
|
}
|
|
|
|
// Create a .note section for an executable or shared library. This
|
|
// records the version of gold used to create the binary.
|
|
|
|
void
|
|
Layout::create_note_section()
|
|
{
|
|
if (parameters->output_is_object())
|
|
return;
|
|
|
|
const int size = parameters->get_size();
|
|
|
|
// The contents of the .note section.
|
|
const char* name = "GNU";
|
|
std::string desc(std::string("gold ") + gold::get_version_string());
|
|
size_t namesz = strlen(name) + 1;
|
|
size_t aligned_namesz = align_address(namesz, size / 8);
|
|
size_t descsz = desc.length() + 1;
|
|
size_t aligned_descsz = align_address(descsz, size / 8);
|
|
const int note_type = 4;
|
|
|
|
size_t notesz = 3 * (size / 8) + aligned_namesz + aligned_descsz;
|
|
|
|
unsigned char buffer[128];
|
|
gold_assert(sizeof buffer >= notesz);
|
|
memset(buffer, 0, notesz);
|
|
|
|
bool is_big_endian = parameters->is_big_endian();
|
|
|
|
if (size == 32)
|
|
{
|
|
if (!is_big_endian)
|
|
{
|
|
elfcpp::Swap<32, false>::writeval(buffer, namesz);
|
|
elfcpp::Swap<32, false>::writeval(buffer + 4, descsz);
|
|
elfcpp::Swap<32, false>::writeval(buffer + 8, note_type);
|
|
}
|
|
else
|
|
{
|
|
elfcpp::Swap<32, true>::writeval(buffer, namesz);
|
|
elfcpp::Swap<32, true>::writeval(buffer + 4, descsz);
|
|
elfcpp::Swap<32, true>::writeval(buffer + 8, note_type);
|
|
}
|
|
}
|
|
else if (size == 64)
|
|
{
|
|
if (!is_big_endian)
|
|
{
|
|
elfcpp::Swap<64, false>::writeval(buffer, namesz);
|
|
elfcpp::Swap<64, false>::writeval(buffer + 8, descsz);
|
|
elfcpp::Swap<64, false>::writeval(buffer + 16, note_type);
|
|
}
|
|
else
|
|
{
|
|
elfcpp::Swap<64, true>::writeval(buffer, namesz);
|
|
elfcpp::Swap<64, true>::writeval(buffer + 8, descsz);
|
|
elfcpp::Swap<64, true>::writeval(buffer + 16, note_type);
|
|
}
|
|
}
|
|
else
|
|
gold_unreachable();
|
|
|
|
memcpy(buffer + 3 * (size / 8), name, namesz);
|
|
memcpy(buffer + 3 * (size / 8) + aligned_namesz, desc.data(), descsz);
|
|
|
|
const char* note_name = this->namepool_.add(".note", NULL);
|
|
Output_section* os = this->make_output_section(note_name,
|
|
elfcpp::SHT_NOTE,
|
|
0);
|
|
Output_section_data* posd = new Output_data_const(buffer, notesz,
|
|
size / 8);
|
|
os->add_output_section_data(posd);
|
|
}
|
|
|
|
// Return whether SEG1 should be before SEG2 in the output file. This
|
|
// is based entirely on the segment type and flags. When this is
|
|
// called the segment addresses has normally not yet been set.
|
|
|
|
bool
|
|
Layout::segment_precedes(const Output_segment* seg1,
|
|
const Output_segment* seg2)
|
|
{
|
|
elfcpp::Elf_Word type1 = seg1->type();
|
|
elfcpp::Elf_Word type2 = seg2->type();
|
|
|
|
// The single PT_PHDR segment is required to precede any loadable
|
|
// segment. We simply make it always first.
|
|
if (type1 == elfcpp::PT_PHDR)
|
|
{
|
|
gold_assert(type2 != elfcpp::PT_PHDR);
|
|
return true;
|
|
}
|
|
if (type2 == elfcpp::PT_PHDR)
|
|
return false;
|
|
|
|
// The single PT_INTERP segment is required to precede any loadable
|
|
// segment. We simply make it always second.
|
|
if (type1 == elfcpp::PT_INTERP)
|
|
{
|
|
gold_assert(type2 != elfcpp::PT_INTERP);
|
|
return true;
|
|
}
|
|
if (type2 == elfcpp::PT_INTERP)
|
|
return false;
|
|
|
|
// We then put PT_LOAD segments before any other segments.
|
|
if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD)
|
|
return true;
|
|
if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
|
|
return false;
|
|
|
|
// We put the PT_TLS segment last, because that is where the dynamic
|
|
// linker expects to find it (this is just for efficiency; other
|
|
// positions would also work correctly).
|
|
if (type1 == elfcpp::PT_TLS && type2 != elfcpp::PT_TLS)
|
|
return false;
|
|
if (type2 == elfcpp::PT_TLS && type1 != elfcpp::PT_TLS)
|
|
return true;
|
|
|
|
const elfcpp::Elf_Word flags1 = seg1->flags();
|
|
const elfcpp::Elf_Word flags2 = seg2->flags();
|
|
|
|
// The order of non-PT_LOAD segments is unimportant. We simply sort
|
|
// by the numeric segment type and flags values. There should not
|
|
// be more than one segment with the same type and flags.
|
|
if (type1 != elfcpp::PT_LOAD)
|
|
{
|
|
if (type1 != type2)
|
|
return type1 < type2;
|
|
gold_assert(flags1 != flags2);
|
|
return flags1 < flags2;
|
|
}
|
|
|
|
// We sort PT_LOAD segments based on the flags. Readonly segments
|
|
// come before writable segments. Then executable segments come
|
|
// before non-executable segments. Then the unlikely case of a
|
|
// non-readable segment comes before the normal case of a readable
|
|
// segment. If there are multiple segments with the same type and
|
|
// flags, we require that the address be set, and we sort by
|
|
// virtual address and then physical address.
|
|
if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W))
|
|
return (flags1 & elfcpp::PF_W) == 0;
|
|
if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X))
|
|
return (flags1 & elfcpp::PF_X) != 0;
|
|
if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R))
|
|
return (flags1 & elfcpp::PF_R) == 0;
|
|
|
|
uint64_t vaddr1 = seg1->vaddr();
|
|
uint64_t vaddr2 = seg2->vaddr();
|
|
if (vaddr1 != vaddr2)
|
|
return vaddr1 < vaddr2;
|
|
|
|
uint64_t paddr1 = seg1->paddr();
|
|
uint64_t paddr2 = seg2->paddr();
|
|
gold_assert(paddr1 != paddr2);
|
|
return paddr1 < paddr2;
|
|
}
|
|
|
|
// Set the file offsets of all the segments, and all the sections they
|
|
// contain. They have all been created. LOAD_SEG must be be laid out
|
|
// first. Return the offset of the data to follow.
|
|
|
|
off_t
|
|
Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
|
|
unsigned int *pshndx)
|
|
{
|
|
// Sort them into the final order.
|
|
std::sort(this->segment_list_.begin(), this->segment_list_.end(),
|
|
Layout::Compare_segments());
|
|
|
|
// Find the PT_LOAD segments, and set their addresses and offsets
|
|
// and their section's addresses and offsets.
|
|
uint64_t addr = target->text_segment_address();
|
|
off_t off = 0;
|
|
bool was_readonly = false;
|
|
for (Segment_list::iterator p = this->segment_list_.begin();
|
|
p != this->segment_list_.end();
|
|
++p)
|
|
{
|
|
if ((*p)->type() == elfcpp::PT_LOAD)
|
|
{
|
|
if (load_seg != NULL && load_seg != *p)
|
|
gold_unreachable();
|
|
load_seg = NULL;
|
|
|
|
// If the last segment was readonly, and this one is not,
|
|
// then skip the address forward one page, maintaining the
|
|
// same position within the page. This lets us store both
|
|
// segments overlapping on a single page in the file, but
|
|
// the loader will put them on different pages in memory.
|
|
|
|
uint64_t orig_addr = addr;
|
|
uint64_t orig_off = off;
|
|
|
|
uint64_t aligned_addr = addr;
|
|
uint64_t abi_pagesize = target->abi_pagesize();
|
|
|
|
// FIXME: This should depend on the -n and -N options.
|
|
(*p)->set_minimum_addralign(target->common_pagesize());
|
|
|
|
if (was_readonly && ((*p)->flags() & elfcpp::PF_W) != 0)
|
|
{
|
|
uint64_t align = (*p)->addralign();
|
|
|
|
addr = align_address(addr, align);
|
|
aligned_addr = addr;
|
|
if ((addr & (abi_pagesize - 1)) != 0)
|
|
addr = addr + abi_pagesize;
|
|
}
|
|
|
|
unsigned int shndx_hold = *pshndx;
|
|
off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
|
|
uint64_t new_addr = (*p)->set_section_addresses(addr, &off, pshndx);
|
|
|
|
// Now that we know the size of this segment, we may be able
|
|
// to save a page in memory, at the cost of wasting some
|
|
// file space, by instead aligning to the start of a new
|
|
// page. Here we use the real machine page size rather than
|
|
// the ABI mandated page size.
|
|
|
|
if (aligned_addr != addr)
|
|
{
|
|
uint64_t common_pagesize = target->common_pagesize();
|
|
uint64_t first_off = (common_pagesize
|
|
- (aligned_addr
|
|
& (common_pagesize - 1)));
|
|
uint64_t last_off = new_addr & (common_pagesize - 1);
|
|
if (first_off > 0
|
|
&& last_off > 0
|
|
&& ((aligned_addr & ~ (common_pagesize - 1))
|
|
!= (new_addr & ~ (common_pagesize - 1)))
|
|
&& first_off + last_off <= common_pagesize)
|
|
{
|
|
*pshndx = shndx_hold;
|
|
addr = align_address(aligned_addr, common_pagesize);
|
|
off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
|
|
new_addr = (*p)->set_section_addresses(addr, &off, pshndx);
|
|
}
|
|
}
|
|
|
|
addr = new_addr;
|
|
|
|
if (((*p)->flags() & elfcpp::PF_W) == 0)
|
|
was_readonly = true;
|
|
}
|
|
}
|
|
|
|
// Handle the non-PT_LOAD segments, setting their offsets from their
|
|
// section's offsets.
|
|
for (Segment_list::iterator p = this->segment_list_.begin();
|
|
p != this->segment_list_.end();
|
|
++p)
|
|
{
|
|
if ((*p)->type() != elfcpp::PT_LOAD)
|
|
(*p)->set_offset();
|
|
}
|
|
|
|
return off;
|
|
}
|
|
|
|
// Set the file offset of all the sections not associated with a
|
|
// segment.
|
|
|
|
off_t
|
|
Layout::set_section_offsets(off_t off, unsigned int* pshndx)
|
|
{
|
|
for (Section_list::iterator p = this->unattached_section_list_.begin();
|
|
p != this->unattached_section_list_.end();
|
|
++p)
|
|
{
|
|
(*p)->set_out_shndx(*pshndx);
|
|
++*pshndx;
|
|
if ((*p)->offset() != -1)
|
|
continue;
|
|
off = align_address(off, (*p)->addralign());
|
|
(*p)->set_address(0, off);
|
|
off += (*p)->data_size();
|
|
}
|
|
return off;
|
|
}
|
|
|
|
// Create the symbol table sections. Here we also set the final
|
|
// values of the symbols. At this point all the loadable sections are
|
|
// fully laid out.
|
|
|
|
void
|
|
Layout::create_symtab_sections(const Input_objects* input_objects,
|
|
Symbol_table* symtab,
|
|
off_t* poff)
|
|
{
|
|
int symsize;
|
|
unsigned int align;
|
|
if (parameters->get_size() == 32)
|
|
{
|
|
symsize = elfcpp::Elf_sizes<32>::sym_size;
|
|
align = 4;
|
|
}
|
|
else if (parameters->get_size() == 64)
|
|
{
|
|
symsize = elfcpp::Elf_sizes<64>::sym_size;
|
|
align = 8;
|
|
}
|
|
else
|
|
gold_unreachable();
|
|
|
|
off_t off = *poff;
|
|
off = align_address(off, align);
|
|
off_t startoff = off;
|
|
|
|
// Save space for the dummy symbol at the start of the section. We
|
|
// never bother to write this out--it will just be left as zero.
|
|
off += symsize;
|
|
unsigned int local_symbol_index = 1;
|
|
|
|
// Add STT_SECTION symbols for each Output section which needs one.
|
|
for (Section_list::iterator p = this->section_list_.begin();
|
|
p != this->section_list_.end();
|
|
++p)
|
|
{
|
|
if (!(*p)->needs_symtab_index())
|
|
(*p)->set_symtab_index(-1U);
|
|
else
|
|
{
|
|
(*p)->set_symtab_index(local_symbol_index);
|
|
++local_symbol_index;
|
|
off += symsize;
|
|
}
|
|
}
|
|
|
|
for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
|
|
p != input_objects->relobj_end();
|
|
++p)
|
|
{
|
|
Task_lock_obj<Object> tlo(**p);
|
|
unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
|
|
off,
|
|
&this->sympool_);
|
|
off += (index - local_symbol_index) * symsize;
|
|
local_symbol_index = index;
|
|
}
|
|
|
|
unsigned int local_symcount = local_symbol_index;
|
|
gold_assert(local_symcount * symsize == off - startoff);
|
|
|
|
off_t dynoff;
|
|
size_t dyn_global_index;
|
|
size_t dyncount;
|
|
if (this->dynsym_section_ == NULL)
|
|
{
|
|
dynoff = 0;
|
|
dyn_global_index = 0;
|
|
dyncount = 0;
|
|
}
|
|
else
|
|
{
|
|
dyn_global_index = this->dynsym_section_->info();
|
|
off_t locsize = dyn_global_index * this->dynsym_section_->entsize();
|
|
dynoff = this->dynsym_section_->offset() + locsize;
|
|
dyncount = (this->dynsym_section_->data_size() - locsize) / symsize;
|
|
gold_assert(static_cast<off_t>(dyncount * symsize)
|
|
== this->dynsym_section_->data_size() - locsize);
|
|
}
|
|
|
|
off = symtab->finalize(local_symcount, off, dynoff, dyn_global_index,
|
|
dyncount, &this->sympool_);
|
|
|
|
if (!parameters->strip_all())
|
|
{
|
|
this->sympool_.set_string_offsets();
|
|
|
|
const char* symtab_name = this->namepool_.add(".symtab", NULL);
|
|
Output_section* osymtab = this->make_output_section(symtab_name,
|
|
elfcpp::SHT_SYMTAB,
|
|
0);
|
|
this->symtab_section_ = osymtab;
|
|
|
|
Output_section_data* pos = new Output_data_space(off - startoff,
|
|
align);
|
|
osymtab->add_output_section_data(pos);
|
|
|
|
const char* strtab_name = this->namepool_.add(".strtab", NULL);
|
|
Output_section* ostrtab = this->make_output_section(strtab_name,
|
|
elfcpp::SHT_STRTAB,
|
|
0);
|
|
|
|
Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
|
|
ostrtab->add_output_section_data(pstr);
|
|
|
|
osymtab->set_address(0, startoff);
|
|
osymtab->set_link_section(ostrtab);
|
|
osymtab->set_info(local_symcount);
|
|
osymtab->set_entsize(symsize);
|
|
|
|
*poff = off;
|
|
}
|
|
}
|
|
|
|
// Create the .shstrtab section, which holds the names of the
|
|
// sections. At the time this is called, we have created all the
|
|
// output sections except .shstrtab itself.
|
|
|
|
Output_section*
|
|
Layout::create_shstrtab()
|
|
{
|
|
// FIXME: We don't need to create a .shstrtab section if we are
|
|
// stripping everything.
|
|
|
|
const char* name = this->namepool_.add(".shstrtab", NULL);
|
|
|
|
this->namepool_.set_string_offsets();
|
|
|
|
Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0);
|
|
|
|
Output_section_data* posd = new Output_data_strtab(&this->namepool_);
|
|
os->add_output_section_data(posd);
|
|
|
|
return os;
|
|
}
|
|
|
|
// Create the section headers. SIZE is 32 or 64. OFF is the file
|
|
// offset.
|
|
|
|
Output_section_headers*
|
|
Layout::create_shdrs(off_t* poff)
|
|
{
|
|
Output_section_headers* oshdrs;
|
|
oshdrs = new Output_section_headers(this,
|
|
&this->segment_list_,
|
|
&this->unattached_section_list_,
|
|
&this->namepool_);
|
|
off_t off = align_address(*poff, oshdrs->addralign());
|
|
oshdrs->set_address(0, off);
|
|
off += oshdrs->data_size();
|
|
*poff = off;
|
|
this->special_output_list_.push_back(oshdrs);
|
|
return oshdrs;
|
|
}
|
|
|
|
// Create the dynamic symbol table.
|
|
|
|
void
|
|
Layout::create_dynamic_symtab(const Target* target, Symbol_table* symtab,
|
|
Output_section **pdynstr,
|
|
unsigned int* plocal_dynamic_count,
|
|
std::vector<Symbol*>* pdynamic_symbols,
|
|
Versions* pversions)
|
|
{
|
|
// Count all the symbols in the dynamic symbol table, and set the
|
|
// dynamic symbol indexes.
|
|
|
|
// Skip symbol 0, which is always all zeroes.
|
|
unsigned int index = 1;
|
|
|
|
// Add STT_SECTION symbols for each Output section which needs one.
|
|
for (Section_list::iterator p = this->section_list_.begin();
|
|
p != this->section_list_.end();
|
|
++p)
|
|
{
|
|
if (!(*p)->needs_dynsym_index())
|
|
(*p)->set_dynsym_index(-1U);
|
|
else
|
|
{
|
|
(*p)->set_dynsym_index(index);
|
|
++index;
|
|
}
|
|
}
|
|
|
|
// FIXME: Some targets apparently require local symbols in the
|
|
// dynamic symbol table. Here is where we will have to count them,
|
|
// and set the dynamic symbol indexes, and add the names to
|
|
// this->dynpool_.
|
|
|
|
unsigned int local_symcount = index;
|
|
*plocal_dynamic_count = local_symcount;
|
|
|
|
// FIXME: We have to tell set_dynsym_indexes whether the
|
|
// -E/--export-dynamic option was used.
|
|
index = symtab->set_dynsym_indexes(&this->options_, target, index,
|
|
pdynamic_symbols, &this->dynpool_,
|
|
pversions);
|
|
|
|
int symsize;
|
|
unsigned int align;
|
|
const int size = parameters->get_size();
|
|
if (size == 32)
|
|
{
|
|
symsize = elfcpp::Elf_sizes<32>::sym_size;
|
|
align = 4;
|
|
}
|
|
else if (size == 64)
|
|
{
|
|
symsize = elfcpp::Elf_sizes<64>::sym_size;
|
|
align = 8;
|
|
}
|
|
else
|
|
gold_unreachable();
|
|
|
|
// Create the dynamic symbol table section.
|
|
|
|
const char* dynsym_name = this->namepool_.add(".dynsym", NULL);
|
|
Output_section* dynsym = this->make_output_section(dynsym_name,
|
|
elfcpp::SHT_DYNSYM,
|
|
elfcpp::SHF_ALLOC);
|
|
|
|
Output_section_data* odata = new Output_data_space(index * symsize,
|
|
align);
|
|
dynsym->add_output_section_data(odata);
|
|
|
|
dynsym->set_info(local_symcount);
|
|
dynsym->set_entsize(symsize);
|
|
dynsym->set_addralign(align);
|
|
|
|
this->dynsym_section_ = dynsym;
|
|
|
|
Output_data_dynamic* const odyn = this->dynamic_data_;
|
|
odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
|
|
odyn->add_constant(elfcpp::DT_SYMENT, symsize);
|
|
|
|
// Create the dynamic string table section.
|
|
|
|
const char* dynstr_name = this->namepool_.add(".dynstr", NULL);
|
|
Output_section* dynstr = this->make_output_section(dynstr_name,
|
|
elfcpp::SHT_STRTAB,
|
|
elfcpp::SHF_ALLOC);
|
|
|
|
Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
|
|
dynstr->add_output_section_data(strdata);
|
|
|
|
dynsym->set_link_section(dynstr);
|
|
this->dynamic_section_->set_link_section(dynstr);
|
|
|
|
odyn->add_section_address(elfcpp::DT_STRTAB, dynstr);
|
|
odyn->add_section_size(elfcpp::DT_STRSZ, dynstr);
|
|
|
|
*pdynstr = dynstr;
|
|
|
|
// Create the hash tables.
|
|
|
|
// FIXME: We need an option to create a GNU hash table.
|
|
|
|
unsigned char* phash;
|
|
unsigned int hashlen;
|
|
Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
|
|
&phash, &hashlen);
|
|
|
|
const char* hash_name = this->namepool_.add(".hash", NULL);
|
|
Output_section* hashsec = this->make_output_section(hash_name,
|
|
elfcpp::SHT_HASH,
|
|
elfcpp::SHF_ALLOC);
|
|
|
|
Output_section_data* hashdata = new Output_data_const_buffer(phash,
|
|
hashlen,
|
|
align);
|
|
hashsec->add_output_section_data(hashdata);
|
|
|
|
hashsec->set_link_section(dynsym);
|
|
hashsec->set_entsize(4);
|
|
|
|
odyn->add_section_address(elfcpp::DT_HASH, hashsec);
|
|
}
|
|
|
|
// Create the version sections.
|
|
|
|
void
|
|
Layout::create_version_sections(const Versions* versions,
|
|
unsigned int local_symcount,
|
|
const std::vector<Symbol*>& dynamic_symbols,
|
|
const Output_section* dynstr)
|
|
{
|
|
if (!versions->any_defs() && !versions->any_needs())
|
|
return;
|
|
|
|
if (parameters->get_size() == 32)
|
|
{
|
|
if (parameters->is_big_endian())
|
|
{
|
|
#ifdef HAVE_TARGET_32_BIG
|
|
this->sized_create_version_sections
|
|
SELECT_SIZE_ENDIAN_NAME(32, true)(
|
|
versions, local_symcount, dynamic_symbols, dynstr
|
|
SELECT_SIZE_ENDIAN(32, true));
|
|
#else
|
|
gold_unreachable();
|
|
#endif
|
|
}
|
|
else
|
|
{
|
|
#ifdef HAVE_TARGET_32_LITTLE
|
|
this->sized_create_version_sections
|
|
SELECT_SIZE_ENDIAN_NAME(32, false)(
|
|
versions, local_symcount, dynamic_symbols, dynstr
|
|
SELECT_SIZE_ENDIAN(32, false));
|
|
#else
|
|
gold_unreachable();
|
|
#endif
|
|
}
|
|
}
|
|
else if (parameters->get_size() == 64)
|
|
{
|
|
if (parameters->is_big_endian())
|
|
{
|
|
#ifdef HAVE_TARGET_64_BIG
|
|
this->sized_create_version_sections
|
|
SELECT_SIZE_ENDIAN_NAME(64, true)(
|
|
versions, local_symcount, dynamic_symbols, dynstr
|
|
SELECT_SIZE_ENDIAN(64, true));
|
|
#else
|
|
gold_unreachable();
|
|
#endif
|
|
}
|
|
else
|
|
{
|
|
#ifdef HAVE_TARGET_64_LITTLE
|
|
this->sized_create_version_sections
|
|
SELECT_SIZE_ENDIAN_NAME(64, false)(
|
|
versions, local_symcount, dynamic_symbols, dynstr
|
|
SELECT_SIZE_ENDIAN(64, false));
|
|
#else
|
|
gold_unreachable();
|
|
#endif
|
|
}
|
|
}
|
|
else
|
|
gold_unreachable();
|
|
}
|
|
|
|
// Create the version sections, sized version.
|
|
|
|
template<int size, bool big_endian>
|
|
void
|
|
Layout::sized_create_version_sections(
|
|
const Versions* versions,
|
|
unsigned int local_symcount,
|
|
const std::vector<Symbol*>& dynamic_symbols,
|
|
const Output_section* dynstr
|
|
ACCEPT_SIZE_ENDIAN)
|
|
{
|
|
const char* vname = this->namepool_.add(".gnu.version", NULL);
|
|
Output_section* vsec = this->make_output_section(vname,
|
|
elfcpp::SHT_GNU_versym,
|
|
elfcpp::SHF_ALLOC);
|
|
|
|
unsigned char* vbuf;
|
|
unsigned int vsize;
|
|
versions->symbol_section_contents SELECT_SIZE_ENDIAN_NAME(size, big_endian)(
|
|
&this->dynpool_, local_symcount, dynamic_symbols, &vbuf, &vsize
|
|
SELECT_SIZE_ENDIAN(size, big_endian));
|
|
|
|
Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2);
|
|
|
|
vsec->add_output_section_data(vdata);
|
|
vsec->set_entsize(2);
|
|
vsec->set_link_section(this->dynsym_section_);
|
|
|
|
Output_data_dynamic* const odyn = this->dynamic_data_;
|
|
odyn->add_section_address(elfcpp::DT_VERSYM, vsec);
|
|
|
|
if (versions->any_defs())
|
|
{
|
|
const char* vdname = this->namepool_.add(".gnu.version_d", NULL);
|
|
Output_section *vdsec;
|
|
vdsec = this->make_output_section(vdname, elfcpp::SHT_GNU_verdef,
|
|
elfcpp::SHF_ALLOC);
|
|
|
|
unsigned char* vdbuf;
|
|
unsigned int vdsize;
|
|
unsigned int vdentries;
|
|
versions->def_section_contents SELECT_SIZE_ENDIAN_NAME(size, big_endian)(
|
|
&this->dynpool_, &vdbuf, &vdsize, &vdentries
|
|
SELECT_SIZE_ENDIAN(size, big_endian));
|
|
|
|
Output_section_data* vddata = new Output_data_const_buffer(vdbuf,
|
|
vdsize,
|
|
4);
|
|
|
|
vdsec->add_output_section_data(vddata);
|
|
vdsec->set_link_section(dynstr);
|
|
vdsec->set_info(vdentries);
|
|
|
|
odyn->add_section_address(elfcpp::DT_VERDEF, vdsec);
|
|
odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries);
|
|
}
|
|
|
|
if (versions->any_needs())
|
|
{
|
|
const char* vnname = this->namepool_.add(".gnu.version_r", NULL);
|
|
Output_section* vnsec;
|
|
vnsec = this->make_output_section(vnname, elfcpp::SHT_GNU_verneed,
|
|
elfcpp::SHF_ALLOC);
|
|
|
|
unsigned char* vnbuf;
|
|
unsigned int vnsize;
|
|
unsigned int vnentries;
|
|
versions->need_section_contents SELECT_SIZE_ENDIAN_NAME(size, big_endian)
|
|
(&this->dynpool_, &vnbuf, &vnsize, &vnentries
|
|
SELECT_SIZE_ENDIAN(size, big_endian));
|
|
|
|
Output_section_data* vndata = new Output_data_const_buffer(vnbuf,
|
|
vnsize,
|
|
4);
|
|
|
|
vnsec->add_output_section_data(vndata);
|
|
vnsec->set_link_section(dynstr);
|
|
vnsec->set_info(vnentries);
|
|
|
|
odyn->add_section_address(elfcpp::DT_VERNEED, vnsec);
|
|
odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries);
|
|
}
|
|
}
|
|
|
|
// Create the .interp section and PT_INTERP segment.
|
|
|
|
void
|
|
Layout::create_interp(const Target* target)
|
|
{
|
|
const char* interp = this->options_.dynamic_linker();
|
|
if (interp == NULL)
|
|
{
|
|
interp = target->dynamic_linker();
|
|
gold_assert(interp != NULL);
|
|
}
|
|
|
|
size_t len = strlen(interp) + 1;
|
|
|
|
Output_section_data* odata = new Output_data_const(interp, len, 1);
|
|
|
|
const char* interp_name = this->namepool_.add(".interp", NULL);
|
|
Output_section* osec = this->make_output_section(interp_name,
|
|
elfcpp::SHT_PROGBITS,
|
|
elfcpp::SHF_ALLOC);
|
|
osec->add_output_section_data(odata);
|
|
|
|
Output_segment* oseg = new Output_segment(elfcpp::PT_INTERP, elfcpp::PF_R);
|
|
this->segment_list_.push_back(oseg);
|
|
oseg->add_initial_output_section(osec, elfcpp::PF_R);
|
|
}
|
|
|
|
// Finish the .dynamic section and PT_DYNAMIC segment.
|
|
|
|
void
|
|
Layout::finish_dynamic_section(const Input_objects* input_objects,
|
|
const Symbol_table* symtab)
|
|
{
|
|
Output_segment* oseg = new Output_segment(elfcpp::PT_DYNAMIC,
|
|
elfcpp::PF_R | elfcpp::PF_W);
|
|
this->segment_list_.push_back(oseg);
|
|
oseg->add_initial_output_section(this->dynamic_section_,
|
|
elfcpp::PF_R | elfcpp::PF_W);
|
|
|
|
Output_data_dynamic* const odyn = this->dynamic_data_;
|
|
|
|
for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin();
|
|
p != input_objects->dynobj_end();
|
|
++p)
|
|
{
|
|
// FIXME: Handle --as-needed.
|
|
odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname());
|
|
}
|
|
|
|
// FIXME: Support --init and --fini.
|
|
Symbol* sym = symtab->lookup("_init");
|
|
if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
|
|
odyn->add_symbol(elfcpp::DT_INIT, sym);
|
|
|
|
sym = symtab->lookup("_fini");
|
|
if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
|
|
odyn->add_symbol(elfcpp::DT_FINI, sym);
|
|
|
|
// FIXME: Support DT_INIT_ARRAY and DT_FINI_ARRAY.
|
|
|
|
// Add a DT_RPATH entry if needed.
|
|
const General_options::Dir_list& rpath(this->options_.rpath());
|
|
if (!rpath.empty())
|
|
{
|
|
std::string rpath_val;
|
|
for (General_options::Dir_list::const_iterator p = rpath.begin();
|
|
p != rpath.end();
|
|
++p)
|
|
{
|
|
if (rpath_val.empty())
|
|
rpath_val = p->name();
|
|
else
|
|
{
|
|
// Eliminate duplicates.
|
|
General_options::Dir_list::const_iterator q;
|
|
for (q = rpath.begin(); q != p; ++q)
|
|
if (q->name() == p->name())
|
|
break;
|
|
if (q == p)
|
|
{
|
|
rpath_val += ':';
|
|
rpath_val += p->name();
|
|
}
|
|
}
|
|
}
|
|
|
|
odyn->add_string(elfcpp::DT_RPATH, rpath_val);
|
|
}
|
|
}
|
|
|
|
// The mapping of .gnu.linkonce section names to real section names.
|
|
|
|
#define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
|
|
const Layout::Linkonce_mapping Layout::linkonce_mapping[] =
|
|
{
|
|
MAPPING_INIT("d.rel.ro", ".data.rel.ro"), // Must be before "d".
|
|
MAPPING_INIT("t", ".text"),
|
|
MAPPING_INIT("r", ".rodata"),
|
|
MAPPING_INIT("d", ".data"),
|
|
MAPPING_INIT("b", ".bss"),
|
|
MAPPING_INIT("s", ".sdata"),
|
|
MAPPING_INIT("sb", ".sbss"),
|
|
MAPPING_INIT("s2", ".sdata2"),
|
|
MAPPING_INIT("sb2", ".sbss2"),
|
|
MAPPING_INIT("wi", ".debug_info"),
|
|
MAPPING_INIT("td", ".tdata"),
|
|
MAPPING_INIT("tb", ".tbss"),
|
|
MAPPING_INIT("lr", ".lrodata"),
|
|
MAPPING_INIT("l", ".ldata"),
|
|
MAPPING_INIT("lb", ".lbss"),
|
|
};
|
|
#undef MAPPING_INIT
|
|
|
|
const int Layout::linkonce_mapping_count =
|
|
sizeof(Layout::linkonce_mapping) / sizeof(Layout::linkonce_mapping[0]);
|
|
|
|
// Return the name of the output section to use for a .gnu.linkonce
|
|
// section. This is based on the default ELF linker script of the old
|
|
// GNU linker. For example, we map a name like ".gnu.linkonce.t.foo"
|
|
// to ".text". Set *PLEN to the length of the name. *PLEN is
|
|
// initialized to the length of NAME.
|
|
|
|
const char*
|
|
Layout::linkonce_output_name(const char* name, size_t *plen)
|
|
{
|
|
const char* s = name + sizeof(".gnu.linkonce") - 1;
|
|
if (*s != '.')
|
|
return name;
|
|
++s;
|
|
const Linkonce_mapping* plm = linkonce_mapping;
|
|
for (int i = 0; i < linkonce_mapping_count; ++i, ++plm)
|
|
{
|
|
if (strncmp(s, plm->from, plm->fromlen) == 0 && s[plm->fromlen] == '.')
|
|
{
|
|
*plen = plm->tolen;
|
|
return plm->to;
|
|
}
|
|
}
|
|
return name;
|
|
}
|
|
|
|
// Choose the output section name to use given an input section name.
|
|
// Set *PLEN to the length of the name. *PLEN is initialized to the
|
|
// length of NAME.
|
|
|
|
const char*
|
|
Layout::output_section_name(const char* name, size_t* plen)
|
|
{
|
|
if (Layout::is_linkonce(name))
|
|
{
|
|
// .gnu.linkonce sections are laid out as though they were named
|
|
// for the sections are placed into.
|
|
return Layout::linkonce_output_name(name, plen);
|
|
}
|
|
|
|
// If the section name has no '.', or only an initial '.', we use
|
|
// the name unchanged (i.e., ".text" is unchanged).
|
|
|
|
// Otherwise, if the section name does not include ".rel", we drop
|
|
// the last '.' and everything that follows (i.e., ".text.XXX"
|
|
// becomes ".text").
|
|
|
|
// Otherwise, if the section name has zero or one '.' after the
|
|
// ".rel", we use the name unchanged (i.e., ".rel.text" is
|
|
// unchanged).
|
|
|
|
// Otherwise, we drop the last '.' and everything that follows
|
|
// (i.e., ".rel.text.XXX" becomes ".rel.text").
|
|
|
|
const char* s = name;
|
|
if (*s == '.')
|
|
++s;
|
|
const char* sdot = strchr(s, '.');
|
|
if (sdot == NULL)
|
|
return name;
|
|
|
|
const char* srel = strstr(s, ".rel");
|
|
if (srel == NULL)
|
|
{
|
|
*plen = sdot - name;
|
|
return name;
|
|
}
|
|
|
|
sdot = strchr(srel + 1, '.');
|
|
if (sdot == NULL)
|
|
return name;
|
|
sdot = strchr(sdot + 1, '.');
|
|
if (sdot == NULL)
|
|
return name;
|
|
|
|
*plen = sdot - name;
|
|
return name;
|
|
}
|
|
|
|
// Record the signature of a comdat section, and return whether to
|
|
// include it in the link. If GROUP is true, this is a regular
|
|
// section group. If GROUP is false, this is a group signature
|
|
// derived from the name of a linkonce section. We want linkonce
|
|
// signatures and group signatures to block each other, but we don't
|
|
// want a linkonce signature to block another linkonce signature.
|
|
|
|
bool
|
|
Layout::add_comdat(const char* signature, bool group)
|
|
{
|
|
std::string sig(signature);
|
|
std::pair<Signatures::iterator, bool> ins(
|
|
this->signatures_.insert(std::make_pair(sig, group)));
|
|
|
|
if (ins.second)
|
|
{
|
|
// This is the first time we've seen this signature.
|
|
return true;
|
|
}
|
|
|
|
if (ins.first->second)
|
|
{
|
|
// We've already seen a real section group with this signature.
|
|
return false;
|
|
}
|
|
else if (group)
|
|
{
|
|
// This is a real section group, and we've already seen a
|
|
// linkonce section with this signature. Record that we've seen
|
|
// a section group, and don't include this section group.
|
|
ins.first->second = true;
|
|
return false;
|
|
}
|
|
else
|
|
{
|
|
// We've already seen a linkonce section and this is a linkonce
|
|
// section. These don't block each other--this may be the same
|
|
// symbol name with different section types.
|
|
return true;
|
|
}
|
|
}
|
|
|
|
// Write out data not associated with a section or the symbol table.
|
|
|
|
void
|
|
Layout::write_data(const Symbol_table* symtab, Output_file* of) const
|
|
{
|
|
if (!parameters->strip_all())
|
|
{
|
|
const Output_section* symtab_section = this->symtab_section_;
|
|
for (Section_list::const_iterator p = this->section_list_.begin();
|
|
p != this->section_list_.end();
|
|
++p)
|
|
{
|
|
if ((*p)->needs_symtab_index())
|
|
{
|
|
gold_assert(symtab_section != NULL);
|
|
unsigned int index = (*p)->symtab_index();
|
|
gold_assert(index > 0 && index != -1U);
|
|
off_t off = (symtab_section->offset()
|
|
+ index * symtab_section->entsize());
|
|
symtab->write_section_symbol(*p, of, off);
|
|
}
|
|
}
|
|
}
|
|
|
|
const Output_section* dynsym_section = this->dynsym_section_;
|
|
for (Section_list::const_iterator p = this->section_list_.begin();
|
|
p != this->section_list_.end();
|
|
++p)
|
|
{
|
|
if ((*p)->needs_dynsym_index())
|
|
{
|
|
gold_assert(dynsym_section != NULL);
|
|
unsigned int index = (*p)->dynsym_index();
|
|
gold_assert(index > 0 && index != -1U);
|
|
off_t off = (dynsym_section->offset()
|
|
+ index * dynsym_section->entsize());
|
|
symtab->write_section_symbol(*p, of, off);
|
|
}
|
|
}
|
|
|
|
// Write out the Output_sections. Most won't have anything to
|
|
// write, since most of the data will come from input sections which
|
|
// are handled elsewhere. But some Output_sections do have
|
|
// Output_data.
|
|
for (Section_list::const_iterator p = this->section_list_.begin();
|
|
p != this->section_list_.end();
|
|
++p)
|
|
(*p)->write(of);
|
|
|
|
// Write out the Output_data which are not in an Output_section.
|
|
for (Data_list::const_iterator p = this->special_output_list_.begin();
|
|
p != this->special_output_list_.end();
|
|
++p)
|
|
(*p)->write(of);
|
|
}
|
|
|
|
// Write_data_task methods.
|
|
|
|
// We can always run this task.
|
|
|
|
Task::Is_runnable_type
|
|
Write_data_task::is_runnable(Workqueue*)
|
|
{
|
|
return IS_RUNNABLE;
|
|
}
|
|
|
|
// We need to unlock FINAL_BLOCKER when finished.
|
|
|
|
Task_locker*
|
|
Write_data_task::locks(Workqueue* workqueue)
|
|
{
|
|
return new Task_locker_block(*this->final_blocker_, workqueue);
|
|
}
|
|
|
|
// Run the task--write out the data.
|
|
|
|
void
|
|
Write_data_task::run(Workqueue*)
|
|
{
|
|
this->layout_->write_data(this->symtab_, this->of_);
|
|
}
|
|
|
|
// Write_symbols_task methods.
|
|
|
|
// We can always run this task.
|
|
|
|
Task::Is_runnable_type
|
|
Write_symbols_task::is_runnable(Workqueue*)
|
|
{
|
|
return IS_RUNNABLE;
|
|
}
|
|
|
|
// We need to unlock FINAL_BLOCKER when finished.
|
|
|
|
Task_locker*
|
|
Write_symbols_task::locks(Workqueue* workqueue)
|
|
{
|
|
return new Task_locker_block(*this->final_blocker_, workqueue);
|
|
}
|
|
|
|
// Run the task--write out the symbols.
|
|
|
|
void
|
|
Write_symbols_task::run(Workqueue*)
|
|
{
|
|
this->symtab_->write_globals(this->target_, this->sympool_, this->dynpool_,
|
|
this->of_);
|
|
}
|
|
|
|
// Close_task_runner methods.
|
|
|
|
// Run the task--close the file.
|
|
|
|
void
|
|
Close_task_runner::run(Workqueue*)
|
|
{
|
|
this->of_->close();
|
|
}
|
|
|
|
// Instantiate the templates we need. We could use the configure
|
|
// script to restrict this to only the ones for implemented targets.
|
|
|
|
#ifdef HAVE_TARGET_32_LITTLE
|
|
template
|
|
Output_section*
|
|
Layout::layout<32, false>(Relobj* object, unsigned int shndx, const char* name,
|
|
const elfcpp::Shdr<32, false>& shdr, off_t*);
|
|
#endif
|
|
|
|
#ifdef HAVE_TARGET_32_BIG
|
|
template
|
|
Output_section*
|
|
Layout::layout<32, true>(Relobj* object, unsigned int shndx, const char* name,
|
|
const elfcpp::Shdr<32, true>& shdr, off_t*);
|
|
#endif
|
|
|
|
#ifdef HAVE_TARGET_64_LITTLE
|
|
template
|
|
Output_section*
|
|
Layout::layout<64, false>(Relobj* object, unsigned int shndx, const char* name,
|
|
const elfcpp::Shdr<64, false>& shdr, off_t*);
|
|
#endif
|
|
|
|
#ifdef HAVE_TARGET_64_BIG
|
|
template
|
|
Output_section*
|
|
Layout::layout<64, true>(Relobj* object, unsigned int shndx, const char* name,
|
|
const elfcpp::Shdr<64, true>& shdr, off_t*);
|
|
#endif
|
|
|
|
|
|
} // End namespace gold.
|