c3b65ac4d0
* layout.cc (is_compressible_debug_section): Fix incorrect
comment about compressed section names.
3686 lines
111 KiB
C++
3686 lines
111 KiB
C++
// layout.cc -- lay out output file sections for gold
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// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
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// Written by Ian Lance Taylor <iant@google.com>.
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// This file is part of gold.
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 3 of the License, or
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// (at your option) any later version.
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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// MA 02110-1301, USA.
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#include "gold.h"
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#include <cerrno>
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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 <fcntl.h>
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#include <unistd.h>
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#include "libiberty.h"
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#include "md5.h"
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#include "sha1.h"
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#include "parameters.h"
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#include "options.h"
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#include "mapfile.h"
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#include "script.h"
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#include "script-sections.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 "compressed_output.h"
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#include "reduced_debug_output.h"
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#include "reloc.h"
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#include "descriptors.h"
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#include "plugin.h"
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#include "incremental.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, const Task* task)
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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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this->target_,
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task);
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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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if (this->mapfile_ != NULL)
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{
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this->mapfile_->print_discarded_sections(this->input_objects_);
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this->layout_->print_to_mapfile(this->mapfile_);
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}
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Output_file* of = new Output_file(parameters->options().output_file_name());
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if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF)
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of->set_is_temporary();
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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(int number_of_input_files, Script_options* script_options)
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: number_of_input_files_(number_of_input_files),
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script_options_(script_options),
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namepool_(),
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sympool_(),
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dynpool_(),
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signatures_(),
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section_name_map_(),
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segment_list_(),
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section_list_(),
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unattached_section_list_(),
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special_output_list_(),
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section_headers_(NULL),
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tls_segment_(NULL),
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relro_segment_(NULL),
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symtab_section_(NULL),
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symtab_xindex_(NULL),
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dynsym_section_(NULL),
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dynsym_xindex_(NULL),
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dynamic_section_(NULL),
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dynamic_data_(NULL),
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eh_frame_section_(NULL),
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eh_frame_data_(NULL),
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added_eh_frame_data_(false),
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eh_frame_hdr_section_(NULL),
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build_id_note_(NULL),
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debug_abbrev_(NULL),
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debug_info_(NULL),
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group_signatures_(),
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output_file_size_(-1),
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sections_are_attached_(false),
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input_requires_executable_stack_(false),
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input_with_gnu_stack_note_(false),
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input_without_gnu_stack_note_(false),
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has_static_tls_(false),
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any_postprocessing_sections_(false),
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resized_signatures_(false),
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have_stabstr_section_(false),
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incremental_inputs_(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 two unattached Output_data objects: the file header and
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// the segment headers.
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this->special_output_list_.reserve(2);
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// Initialize structure needed for an incremental build.
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if (parameters->options().incremental())
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this->incremental_inputs_ = new Incremental_inputs;
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// The section name pool is worth optimizing in all cases, because
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// it is small, but there are often overlaps due to .rel sections.
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this->namepool_.set_optimize();
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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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// Returns whether the given section is in the list of
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// debug-sections-used-by-some-version-of-gdb. Currently,
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// we've checked versions of gdb up to and including 6.7.1.
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static const char* gdb_sections[] =
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{ ".debug_abbrev",
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// ".debug_aranges", // not used by gdb as of 6.7.1
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".debug_frame",
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".debug_info",
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".debug_line",
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".debug_loc",
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".debug_macinfo",
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// ".debug_pubnames", // not used by gdb as of 6.7.1
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".debug_ranges",
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".debug_str",
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};
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static const char* lines_only_debug_sections[] =
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{ ".debug_abbrev",
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// ".debug_aranges", // not used by gdb as of 6.7.1
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// ".debug_frame",
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".debug_info",
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".debug_line",
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// ".debug_loc",
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// ".debug_macinfo",
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// ".debug_pubnames", // not used by gdb as of 6.7.1
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// ".debug_ranges",
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".debug_str",
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};
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static inline bool
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is_gdb_debug_section(const char* str)
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{
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// We can do this faster: binary search or a hashtable. But why bother?
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for (size_t i = 0; i < sizeof(gdb_sections)/sizeof(*gdb_sections); ++i)
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if (strcmp(str, gdb_sections[i]) == 0)
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return true;
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return false;
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}
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static inline bool
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is_lines_only_debug_section(const char* str)
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{
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// We can do this faster: binary search or a hashtable. But why bother?
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for (size_t i = 0;
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i < sizeof(lines_only_debug_sections)/sizeof(*lines_only_debug_sections);
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++i)
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if (strcmp(str, lines_only_debug_sections[i]) == 0)
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return true;
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return false;
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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(Sized_relobj<size, big_endian>*, const char* name,
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const elfcpp::Shdr<size, big_endian>& shdr)
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{
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if (shdr.get_sh_flags() & elfcpp::SHF_EXCLUDE)
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return false;
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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_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_STRTAB:
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// Discard the sections which have special meanings in the ELF
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// ABI. Keep others (e.g., .stabstr). We could also do this by
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// checking the sh_link fields of the appropriate sections.
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return (strcmp(name, ".dynstr") != 0
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&& strcmp(name, ".strtab") != 0
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&& strcmp(name, ".shstrtab") != 0);
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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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// If we are emitting relocations these should be handled
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// elsewhere.
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gold_assert(!parameters->options().relocatable()
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&& !parameters->options().emit_relocs());
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return false;
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case elfcpp::SHT_PROGBITS:
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if (parameters->options().strip_debug()
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&& (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
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{
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if (is_debug_info_section(name))
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return false;
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}
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if (parameters->options().strip_debug_non_line()
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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_lines_only_debug_section(name))
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return false;
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}
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if (parameters->options().strip_debug_gdb()
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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_gdb_debug_section(name))
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return false;
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}
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if (parameters->options().strip_lto_sections()
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&& !parameters->options().relocatable()
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&& (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
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{
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// Ignore LTO sections containing intermediate code.
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if (is_prefix_of(".gnu.lto_", 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_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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if (strcmp((*p)->name(), name) == 0)
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return *p;
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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. NAME must be canonicalized in the string
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// pool, and NAME_KEY is the key.
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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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elfcpp::Elf_Xword lookup_flags = flags;
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// Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
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// read-write with read-only sections. Some other ELF linkers do
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// not do this. FIXME: Perhaps there should be an option
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// controlling this.
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lookup_flags &= ~(elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
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const Key key(name_key, std::make_pair(type, lookup_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. For compatibility with the GNU linker, we
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// combine sections with contents and zero flags with sections
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// with non-zero flags. This is a workaround for cases where
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// assembler code forgets to set section flags. FIXME: Perhaps
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// there should be an option to control this.
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Output_section* os = NULL;
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if (type == elfcpp::SHT_PROGBITS)
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{
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if (flags == 0)
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{
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Output_section* same_name = this->find_output_section(name);
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if (same_name != NULL
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&& same_name->type() == elfcpp::SHT_PROGBITS
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&& (same_name->flags() & elfcpp::SHF_TLS) == 0)
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os = same_name;
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}
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else if ((flags & elfcpp::SHF_TLS) == 0)
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{
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elfcpp::Elf_Xword zero_flags = 0;
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const Key zero_key(name_key, std::make_pair(type, zero_flags));
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Section_name_map::iterator p =
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this->section_name_map_.find(zero_key);
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if (p != this->section_name_map_.end())
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os = p->second;
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}
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}
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if (os == NULL)
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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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// Pick the output section to use for section NAME, in input file
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// RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
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// linker created section. IS_INPUT_SECTION is true if we are
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// choosing an output section for an input section found in a input
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// file. This will return NULL if the input section should be
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// discarded.
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Output_section*
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Layout::choose_output_section(const Relobj* relobj, const char* name,
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elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
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bool is_input_section)
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{
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// We should not see any input sections after we have attached
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// sections to segments.
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gold_assert(!is_input_section || !this->sections_are_attached_);
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// Some flags in the input section should not be automatically
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// copied to the output section.
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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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if (this->script_options_->saw_sections_clause())
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{
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// We are using a SECTIONS clause, so the output section is
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// chosen based only on the name.
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Script_sections* ss = this->script_options_->script_sections();
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const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
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Output_section** output_section_slot;
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name = ss->output_section_name(file_name, name, &output_section_slot);
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if (name == NULL)
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{
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// The SECTIONS clause says to discard this input section.
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return NULL;
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}
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// If this is an orphan section--one not mentioned in the linker
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// script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
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// default processing below.
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if (output_section_slot != NULL)
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{
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if (*output_section_slot != NULL)
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{
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(*output_section_slot)->update_flags_for_input_section(flags);
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return *output_section_slot;
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}
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// We don't put sections found in the linker script into
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// SECTION_NAME_MAP_. That keeps us from getting confused
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// if an orphan section is mapped to a section with the same
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// name as one in the linker script.
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name = this->namepool_.add(name, false, NULL);
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Output_section* os = this->make_output_section(name, type, flags);
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os->set_found_in_sections_clause();
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*output_section_slot = os;
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return os;
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}
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}
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// FIXME: Handle SHF_OS_NONCONFORMING somewhere.
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// Turn NAME from the name of the input section into the name of the
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// output section.
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size_t len = strlen(name);
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if (is_input_section
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&& !this->script_options_->saw_sections_clause()
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&& !parameters->options().relocatable())
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name = Layout::output_section_name(name, &len);
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Stringpool::Key name_key;
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name = this->namepool_.add_with_length(name, len, true, &name_key);
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// Find or make the output section. The output section is selected
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// based on the section name, type, and flags.
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return this->get_output_section(name, name_key, type, flags);
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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. RELOC_SHNDX is the
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// index of a relocation section which applies to this section, or 0
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// if none, or -1U if more than one. RELOC_TYPE is the type of the
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// relocation section if there is one. Set *OFF to the offset of this
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// input section without the output section. Return NULL if the
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// section should be discarded. Set *OFF to -1 if the section
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// contents should not be written directly to the output file, but
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// will instead receive special handling.
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template<int size, bool big_endian>
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Output_section*
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Layout::layout(Sized_relobj<size, big_endian>* object, unsigned int shndx,
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const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
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unsigned int reloc_shndx, unsigned int, off_t* off)
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{
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*off = 0;
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if (!this->include_section(object, name, shdr))
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return NULL;
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Output_section* os;
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// In a relocatable link a grouped section must not be combined with
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// any other sections.
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if (parameters->options().relocatable()
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&& (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0)
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{
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name = this->namepool_.add(name, true, NULL);
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os = this->make_output_section(name, shdr.get_sh_type(),
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shdr.get_sh_flags());
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}
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else
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{
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os = this->choose_output_section(object, name, shdr.get_sh_type(),
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shdr.get_sh_flags(), true);
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if (os == NULL)
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return NULL;
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}
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// By default the GNU linker sorts input sections whose names match
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// .ctor.*, .dtor.*, .init_array.*, or .fini_array.*. The sections
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// are sorted by name. This is used to implement constructor
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// priority ordering. We are compatible.
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if (!this->script_options_->saw_sections_clause()
|
|
&& (is_prefix_of(".ctors.", name)
|
|
|| is_prefix_of(".dtors.", name)
|
|
|| is_prefix_of(".init_array.", name)
|
|
|| is_prefix_of(".fini_array.", name)))
|
|
os->set_must_sort_attached_input_sections();
|
|
|
|
// FIXME: Handle SHF_LINK_ORDER somewhere.
|
|
|
|
*off = os->add_input_section(object, shndx, name, shdr, reloc_shndx,
|
|
this->script_options_->saw_sections_clause());
|
|
|
|
return os;
|
|
}
|
|
|
|
// Handle a relocation section when doing a relocatable link.
|
|
|
|
template<int size, bool big_endian>
|
|
Output_section*
|
|
Layout::layout_reloc(Sized_relobj<size, big_endian>* object,
|
|
unsigned int,
|
|
const elfcpp::Shdr<size, big_endian>& shdr,
|
|
Output_section* data_section,
|
|
Relocatable_relocs* rr)
|
|
{
|
|
gold_assert(parameters->options().relocatable()
|
|
|| parameters->options().emit_relocs());
|
|
|
|
int sh_type = shdr.get_sh_type();
|
|
|
|
std::string name;
|
|
if (sh_type == elfcpp::SHT_REL)
|
|
name = ".rel";
|
|
else if (sh_type == elfcpp::SHT_RELA)
|
|
name = ".rela";
|
|
else
|
|
gold_unreachable();
|
|
name += data_section->name();
|
|
|
|
Output_section* os = this->choose_output_section(object, name.c_str(),
|
|
sh_type,
|
|
shdr.get_sh_flags(),
|
|
false);
|
|
|
|
os->set_should_link_to_symtab();
|
|
os->set_info_section(data_section);
|
|
|
|
Output_section_data* posd;
|
|
if (sh_type == elfcpp::SHT_REL)
|
|
{
|
|
os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
|
|
posd = new Output_relocatable_relocs<elfcpp::SHT_REL,
|
|
size,
|
|
big_endian>(rr);
|
|
}
|
|
else if (sh_type == elfcpp::SHT_RELA)
|
|
{
|
|
os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
|
|
posd = new Output_relocatable_relocs<elfcpp::SHT_RELA,
|
|
size,
|
|
big_endian>(rr);
|
|
}
|
|
else
|
|
gold_unreachable();
|
|
|
|
os->add_output_section_data(posd);
|
|
rr->set_output_data(posd);
|
|
|
|
return os;
|
|
}
|
|
|
|
// Handle a group section when doing a relocatable link.
|
|
|
|
template<int size, bool big_endian>
|
|
void
|
|
Layout::layout_group(Symbol_table* symtab,
|
|
Sized_relobj<size, big_endian>* object,
|
|
unsigned int,
|
|
const char* group_section_name,
|
|
const char* signature,
|
|
const elfcpp::Shdr<size, big_endian>& shdr,
|
|
elfcpp::Elf_Word flags,
|
|
std::vector<unsigned int>* shndxes)
|
|
{
|
|
gold_assert(parameters->options().relocatable());
|
|
gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP);
|
|
group_section_name = this->namepool_.add(group_section_name, true, NULL);
|
|
Output_section* os = this->make_output_section(group_section_name,
|
|
elfcpp::SHT_GROUP,
|
|
shdr.get_sh_flags());
|
|
|
|
// We need to find a symbol with the signature in the symbol table.
|
|
// If we don't find one now, we need to look again later.
|
|
Symbol* sym = symtab->lookup(signature, NULL);
|
|
if (sym != NULL)
|
|
os->set_info_symndx(sym);
|
|
else
|
|
{
|
|
// Reserve some space to minimize reallocations.
|
|
if (this->group_signatures_.empty())
|
|
this->group_signatures_.reserve(this->number_of_input_files_ * 16);
|
|
|
|
// We will wind up using a symbol whose name is the signature.
|
|
// So just put the signature in the symbol name pool to save it.
|
|
signature = symtab->canonicalize_name(signature);
|
|
this->group_signatures_.push_back(Group_signature(os, signature));
|
|
}
|
|
|
|
os->set_should_link_to_symtab();
|
|
os->set_entsize(4);
|
|
|
|
section_size_type entry_count =
|
|
convert_to_section_size_type(shdr.get_sh_size() / 4);
|
|
Output_section_data* posd =
|
|
new Output_data_group<size, big_endian>(object, entry_count, flags,
|
|
shndxes);
|
|
os->add_output_section_data(posd);
|
|
}
|
|
|
|
// Special GNU handling of sections name .eh_frame. They will
|
|
// normally hold exception frame data as defined by the C++ ABI
|
|
// (http://codesourcery.com/cxx-abi/).
|
|
|
|
template<int size, bool big_endian>
|
|
Output_section*
|
|
Layout::layout_eh_frame(Sized_relobj<size, big_endian>* object,
|
|
const unsigned char* symbols,
|
|
off_t symbols_size,
|
|
const unsigned char* symbol_names,
|
|
off_t symbol_names_size,
|
|
unsigned int shndx,
|
|
const elfcpp::Shdr<size, big_endian>& shdr,
|
|
unsigned int reloc_shndx, unsigned int reloc_type,
|
|
off_t* off)
|
|
{
|
|
gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS);
|
|
gold_assert((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
|
|
|
|
const char* const name = ".eh_frame";
|
|
Output_section* os = this->choose_output_section(object,
|
|
name,
|
|
elfcpp::SHT_PROGBITS,
|
|
elfcpp::SHF_ALLOC,
|
|
false);
|
|
if (os == NULL)
|
|
return NULL;
|
|
|
|
if (this->eh_frame_section_ == NULL)
|
|
{
|
|
this->eh_frame_section_ = os;
|
|
this->eh_frame_data_ = new Eh_frame();
|
|
|
|
if (parameters->options().eh_frame_hdr())
|
|
{
|
|
Output_section* hdr_os =
|
|
this->choose_output_section(NULL,
|
|
".eh_frame_hdr",
|
|
elfcpp::SHT_PROGBITS,
|
|
elfcpp::SHF_ALLOC,
|
|
false);
|
|
|
|
if (hdr_os != NULL)
|
|
{
|
|
Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os,
|
|
this->eh_frame_data_);
|
|
hdr_os->add_output_section_data(hdr_posd);
|
|
|
|
hdr_os->set_after_input_sections();
|
|
|
|
if (!this->script_options_->saw_phdrs_clause())
|
|
{
|
|
Output_segment* hdr_oseg;
|
|
hdr_oseg = this->make_output_segment(elfcpp::PT_GNU_EH_FRAME,
|
|
elfcpp::PF_R);
|
|
hdr_oseg->add_output_section(hdr_os, elfcpp::PF_R);
|
|
}
|
|
|
|
this->eh_frame_data_->set_eh_frame_hdr(hdr_posd);
|
|
}
|
|
}
|
|
}
|
|
|
|
gold_assert(this->eh_frame_section_ == os);
|
|
|
|
if (this->eh_frame_data_->add_ehframe_input_section(object,
|
|
symbols,
|
|
symbols_size,
|
|
symbol_names,
|
|
symbol_names_size,
|
|
shndx,
|
|
reloc_shndx,
|
|
reloc_type))
|
|
{
|
|
os->update_flags_for_input_section(shdr.get_sh_flags());
|
|
|
|
// We found a .eh_frame section we are going to optimize, so now
|
|
// we can add the set of optimized sections to the output
|
|
// section. We need to postpone adding this until we've found a
|
|
// section we can optimize so that the .eh_frame section in
|
|
// crtbegin.o winds up at the start of the output section.
|
|
if (!this->added_eh_frame_data_)
|
|
{
|
|
os->add_output_section_data(this->eh_frame_data_);
|
|
this->added_eh_frame_data_ = true;
|
|
}
|
|
*off = -1;
|
|
}
|
|
else
|
|
{
|
|
// We couldn't handle this .eh_frame section for some reason.
|
|
// Add it as a normal section.
|
|
bool saw_sections_clause = this->script_options_->saw_sections_clause();
|
|
*off = os->add_input_section(object, shndx, name, shdr, reloc_shndx,
|
|
saw_sections_clause);
|
|
}
|
|
|
|
return os;
|
|
}
|
|
|
|
// Add POSD to an output section using NAME, TYPE, and FLAGS. Return
|
|
// the output section.
|
|
|
|
Output_section*
|
|
Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
|
|
elfcpp::Elf_Xword flags,
|
|
Output_section_data* posd)
|
|
{
|
|
Output_section* os = this->choose_output_section(NULL, name, type, flags,
|
|
false);
|
|
if (os != NULL)
|
|
os->add_output_section_data(posd);
|
|
return os;
|
|
}
|
|
|
|
// Map section flags to segment flags.
|
|
|
|
elfcpp::Elf_Word
|
|
Layout::section_flags_to_segment(elfcpp::Elf_Xword flags)
|
|
{
|
|
elfcpp::Elf_Word ret = elfcpp::PF_R;
|
|
if ((flags & elfcpp::SHF_WRITE) != 0)
|
|
ret |= elfcpp::PF_W;
|
|
if ((flags & elfcpp::SHF_EXECINSTR) != 0)
|
|
ret |= elfcpp::PF_X;
|
|
return ret;
|
|
}
|
|
|
|
// Sometimes we compress sections. This is typically done for
|
|
// sections that are not part of normal program execution (such as
|
|
// .debug_* sections), and where the readers of these sections know
|
|
// how to deal with compressed sections. This routine doesn't say for
|
|
// certain whether we'll compress -- it depends on commandline options
|
|
// as well -- just whether this section is a candidate for compression.
|
|
// (The Output_compressed_section class decides whether to compress
|
|
// a given section, and picks the name of the compressed section.)
|
|
|
|
static bool
|
|
is_compressible_debug_section(const char* secname)
|
|
{
|
|
return (strncmp(secname, ".debug", sizeof(".debug") - 1) == 0);
|
|
}
|
|
|
|
// Make a new Output_section, and attach it to segments as
|
|
// appropriate.
|
|
|
|
Output_section*
|
|
Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
|
|
elfcpp::Elf_Xword flags)
|
|
{
|
|
Output_section* os;
|
|
if ((flags & elfcpp::SHF_ALLOC) == 0
|
|
&& strcmp(parameters->options().compress_debug_sections(), "none") != 0
|
|
&& is_compressible_debug_section(name))
|
|
os = new Output_compressed_section(¶meters->options(), name, type,
|
|
flags);
|
|
|
|
else if ((flags & elfcpp::SHF_ALLOC) == 0
|
|
&& parameters->options().strip_debug_non_line()
|
|
&& strcmp(".debug_abbrev", name) == 0)
|
|
{
|
|
os = this->debug_abbrev_ = new Output_reduced_debug_abbrev_section(
|
|
name, type, flags);
|
|
if (this->debug_info_)
|
|
this->debug_info_->set_abbreviations(this->debug_abbrev_);
|
|
}
|
|
else if ((flags & elfcpp::SHF_ALLOC) == 0
|
|
&& parameters->options().strip_debug_non_line()
|
|
&& strcmp(".debug_info", name) == 0)
|
|
{
|
|
os = this->debug_info_ = new Output_reduced_debug_info_section(
|
|
name, type, flags);
|
|
if (this->debug_abbrev_)
|
|
this->debug_info_->set_abbreviations(this->debug_abbrev_);
|
|
}
|
|
else
|
|
os = new Output_section(name, type, flags);
|
|
|
|
parameters->target().new_output_section(os);
|
|
|
|
this->section_list_.push_back(os);
|
|
|
|
// The GNU linker by default sorts some sections by priority, so we
|
|
// do the same. We need to know that this might happen before we
|
|
// attach any input sections.
|
|
if (!this->script_options_->saw_sections_clause()
|
|
&& (strcmp(name, ".ctors") == 0
|
|
|| strcmp(name, ".dtors") == 0
|
|
|| strcmp(name, ".init_array") == 0
|
|
|| strcmp(name, ".fini_array") == 0))
|
|
os->set_may_sort_attached_input_sections();
|
|
|
|
// With -z relro, we have to recognize the special sections by name.
|
|
// There is no other way.
|
|
if (!this->script_options_->saw_sections_clause()
|
|
&& parameters->options().relro()
|
|
&& type == elfcpp::SHT_PROGBITS
|
|
&& (flags & elfcpp::SHF_ALLOC) != 0
|
|
&& (flags & elfcpp::SHF_WRITE) != 0)
|
|
{
|
|
if (strcmp(name, ".data.rel.ro") == 0)
|
|
os->set_is_relro();
|
|
else if (strcmp(name, ".data.rel.ro.local") == 0)
|
|
{
|
|
os->set_is_relro();
|
|
os->set_is_relro_local();
|
|
}
|
|
}
|
|
|
|
// Check for .stab*str sections, as .stab* sections need to link to
|
|
// them.
|
|
if (type == elfcpp::SHT_STRTAB
|
|
&& !this->have_stabstr_section_
|
|
&& strncmp(name, ".stab", 5) == 0
|
|
&& strcmp(name + strlen(name) - 3, "str") == 0)
|
|
this->have_stabstr_section_ = true;
|
|
|
|
// If we have already attached the sections to segments, then we
|
|
// need to attach this one now. This happens for sections created
|
|
// directly by the linker.
|
|
if (this->sections_are_attached_)
|
|
this->attach_section_to_segment(os);
|
|
|
|
return os;
|
|
}
|
|
|
|
// Attach output sections to segments. This is called after we have
|
|
// seen all the input sections.
|
|
|
|
void
|
|
Layout::attach_sections_to_segments()
|
|
{
|
|
for (Section_list::iterator p = this->section_list_.begin();
|
|
p != this->section_list_.end();
|
|
++p)
|
|
this->attach_section_to_segment(*p);
|
|
|
|
this->sections_are_attached_ = true;
|
|
}
|
|
|
|
// Attach an output section to a segment.
|
|
|
|
void
|
|
Layout::attach_section_to_segment(Output_section* os)
|
|
{
|
|
if ((os->flags() & elfcpp::SHF_ALLOC) == 0)
|
|
this->unattached_section_list_.push_back(os);
|
|
else
|
|
this->attach_allocated_section_to_segment(os);
|
|
}
|
|
|
|
// Attach an allocated output section to a segment.
|
|
|
|
void
|
|
Layout::attach_allocated_section_to_segment(Output_section* os)
|
|
{
|
|
elfcpp::Elf_Xword flags = os->flags();
|
|
gold_assert((flags & elfcpp::SHF_ALLOC) != 0);
|
|
|
|
if (parameters->options().relocatable())
|
|
return;
|
|
|
|
// If we have a SECTIONS clause, we can't handle the attachment to
|
|
// segments until after we've seen all the sections.
|
|
if (this->script_options_->saw_sections_clause())
|
|
return;
|
|
|
|
gold_assert(!this->script_options_->saw_phdrs_clause());
|
|
|
|
// This output section goes into a PT_LOAD segment.
|
|
|
|
elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);
|
|
|
|
// In general the only thing we really care about for PT_LOAD
|
|
// segments is whether or not they are writable, so that is how we
|
|
// search for them. Large data sections also go into their own
|
|
// PT_LOAD segment. People who need segments sorted on some other
|
|
// basis will have to use a linker script.
|
|
|
|
Segment_list::const_iterator p;
|
|
for (p = this->segment_list_.begin();
|
|
p != this->segment_list_.end();
|
|
++p)
|
|
{
|
|
if ((*p)->type() != elfcpp::PT_LOAD)
|
|
continue;
|
|
if (!parameters->options().omagic()
|
|
&& ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W))
|
|
continue;
|
|
// If -Tbss was specified, we need to separate the data and BSS
|
|
// segments.
|
|
if (parameters->options().user_set_Tbss())
|
|
{
|
|
if ((os->type() == elfcpp::SHT_NOBITS)
|
|
== (*p)->has_any_data_sections())
|
|
continue;
|
|
}
|
|
if (os->is_large_data_section() && !(*p)->is_large_data_segment())
|
|
continue;
|
|
|
|
(*p)->add_output_section(os, seg_flags);
|
|
break;
|
|
}
|
|
|
|
if (p == this->segment_list_.end())
|
|
{
|
|
Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD,
|
|
seg_flags);
|
|
if (os->is_large_data_section())
|
|
oseg->set_is_large_data_segment();
|
|
oseg->add_output_section(os, seg_flags);
|
|
}
|
|
|
|
// If we see a loadable SHT_NOTE section, we create a PT_NOTE
|
|
// segment.
|
|
if (os->type() == elfcpp::SHT_NOTE)
|
|
{
|
|
// See if we already have an equivalent PT_NOTE segment.
|
|
for (p = this->segment_list_.begin();
|
|
p != segment_list_.end();
|
|
++p)
|
|
{
|
|
if ((*p)->type() == elfcpp::PT_NOTE
|
|
&& (((*p)->flags() & elfcpp::PF_W)
|
|
== (seg_flags & elfcpp::PF_W)))
|
|
{
|
|
(*p)->add_output_section(os, seg_flags);
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (p == this->segment_list_.end())
|
|
{
|
|
Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE,
|
|
seg_flags);
|
|
oseg->add_output_section(os, seg_flags);
|
|
}
|
|
}
|
|
|
|
// If we see a loadable SHF_TLS section, we create a PT_TLS
|
|
// segment. There can only be one such segment.
|
|
if ((flags & elfcpp::SHF_TLS) != 0)
|
|
{
|
|
if (this->tls_segment_ == NULL)
|
|
this->make_output_segment(elfcpp::PT_TLS, seg_flags);
|
|
this->tls_segment_->add_output_section(os, seg_flags);
|
|
}
|
|
|
|
// If -z relro is in effect, and we see a relro section, we create a
|
|
// PT_GNU_RELRO segment. There can only be one such segment.
|
|
if (os->is_relro() && parameters->options().relro())
|
|
{
|
|
gold_assert(seg_flags == (elfcpp::PF_R | elfcpp::PF_W));
|
|
if (this->relro_segment_ == NULL)
|
|
this->make_output_segment(elfcpp::PT_GNU_RELRO, seg_flags);
|
|
this->relro_segment_->add_output_section(os, seg_flags);
|
|
}
|
|
}
|
|
|
|
// Make an output section for a script.
|
|
|
|
Output_section*
|
|
Layout::make_output_section_for_script(const char* name)
|
|
{
|
|
name = this->namepool_.add(name, false, NULL);
|
|
Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS,
|
|
elfcpp::SHF_ALLOC);
|
|
os->set_found_in_sections_clause();
|
|
return os;
|
|
}
|
|
|
|
// Return the number of segments we expect to see.
|
|
|
|
size_t
|
|
Layout::expected_segment_count() const
|
|
{
|
|
size_t ret = this->segment_list_.size();
|
|
|
|
// If we didn't see a SECTIONS clause in a linker script, we should
|
|
// already have the complete list of segments. Otherwise we ask the
|
|
// SECTIONS clause how many segments it expects, and add in the ones
|
|
// we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
|
|
|
|
if (!this->script_options_->saw_sections_clause())
|
|
return ret;
|
|
else
|
|
{
|
|
const Script_sections* ss = this->script_options_->script_sections();
|
|
return ret + ss->expected_segment_count(this);
|
|
}
|
|
}
|
|
|
|
// Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
|
|
// is whether we saw a .note.GNU-stack section in the object file.
|
|
// GNU_STACK_FLAGS is the section flags. The flags give the
|
|
// protection required for stack memory. We record this in an
|
|
// executable as a PT_GNU_STACK segment. If an object file does not
|
|
// have a .note.GNU-stack segment, we must assume that it is an old
|
|
// object. On some targets that will force an executable stack.
|
|
|
|
void
|
|
Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags)
|
|
{
|
|
if (!seen_gnu_stack)
|
|
this->input_without_gnu_stack_note_ = true;
|
|
else
|
|
{
|
|
this->input_with_gnu_stack_note_ = true;
|
|
if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
|
|
this->input_requires_executable_stack_ = true;
|
|
}
|
|
}
|
|
|
|
// Create automatic note sections.
|
|
|
|
void
|
|
Layout::create_notes()
|
|
{
|
|
this->create_gold_note();
|
|
this->create_executable_stack_info();
|
|
this->create_build_id();
|
|
}
|
|
|
|
// Create the dynamic sections which are needed before we read the
|
|
// relocs.
|
|
|
|
void
|
|
Layout::create_initial_dynamic_sections(Symbol_table* symtab)
|
|
{
|
|
if (parameters->doing_static_link())
|
|
return;
|
|
|
|
this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic",
|
|
elfcpp::SHT_DYNAMIC,
|
|
(elfcpp::SHF_ALLOC
|
|
| elfcpp::SHF_WRITE),
|
|
false);
|
|
this->dynamic_section_->set_is_relro();
|
|
|
|
symtab->define_in_output_data("_DYNAMIC", NULL, this->dynamic_section_, 0, 0,
|
|
elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
|
|
elfcpp::STV_HIDDEN, 0, false, false);
|
|
|
|
this->dynamic_data_ = new Output_data_dynamic(&this->dynpool_);
|
|
|
|
this->dynamic_section_->add_output_section_data(this->dynamic_data_);
|
|
}
|
|
|
|
// For each output section whose name can be represented as C symbol,
|
|
// define __start and __stop symbols for the section. This is a GNU
|
|
// extension.
|
|
|
|
void
|
|
Layout::define_section_symbols(Symbol_table* symtab)
|
|
{
|
|
for (Section_list::const_iterator p = this->section_list_.begin();
|
|
p != this->section_list_.end();
|
|
++p)
|
|
{
|
|
const char* const name = (*p)->name();
|
|
if (name[strspn(name,
|
|
("0123456789"
|
|
"ABCDEFGHIJKLMNOPWRSTUVWXYZ"
|
|
"abcdefghijklmnopqrstuvwxyz"
|
|
"_"))]
|
|
== '\0')
|
|
{
|
|
const std::string name_string(name);
|
|
const std::string start_name("__start_" + name_string);
|
|
const std::string stop_name("__stop_" + name_string);
|
|
|
|
symtab->define_in_output_data(start_name.c_str(),
|
|
NULL, // version
|
|
*p,
|
|
0, // value
|
|
0, // symsize
|
|
elfcpp::STT_NOTYPE,
|
|
elfcpp::STB_GLOBAL,
|
|
elfcpp::STV_DEFAULT,
|
|
0, // nonvis
|
|
false, // offset_is_from_end
|
|
true); // only_if_ref
|
|
|
|
symtab->define_in_output_data(stop_name.c_str(),
|
|
NULL, // version
|
|
*p,
|
|
0, // value
|
|
0, // symsize
|
|
elfcpp::STT_NOTYPE,
|
|
elfcpp::STB_GLOBAL,
|
|
elfcpp::STV_DEFAULT,
|
|
0, // nonvis
|
|
true, // offset_is_from_end
|
|
true); // only_if_ref
|
|
}
|
|
}
|
|
}
|
|
|
|
// Define symbols for group signatures.
|
|
|
|
void
|
|
Layout::define_group_signatures(Symbol_table* symtab)
|
|
{
|
|
for (Group_signatures::iterator p = this->group_signatures_.begin();
|
|
p != this->group_signatures_.end();
|
|
++p)
|
|
{
|
|
Symbol* sym = symtab->lookup(p->signature, NULL);
|
|
if (sym != NULL)
|
|
p->section->set_info_symndx(sym);
|
|
else
|
|
{
|
|
// Force the name of the group section to the group
|
|
// signature, and use the group's section symbol as the
|
|
// signature symbol.
|
|
if (strcmp(p->section->name(), p->signature) != 0)
|
|
{
|
|
const char* name = this->namepool_.add(p->signature,
|
|
true, NULL);
|
|
p->section->set_name(name);
|
|
}
|
|
p->section->set_needs_symtab_index();
|
|
p->section->set_info_section_symndx(p->section);
|
|
}
|
|
}
|
|
|
|
this->group_signatures_.clear();
|
|
}
|
|
|
|
// Find the first read-only PT_LOAD segment, creating one if
|
|
// necessary.
|
|
|
|
Output_segment*
|
|
Layout::find_first_load_seg()
|
|
{
|
|
for (Segment_list::const_iterator p = this->segment_list_.begin();
|
|
p != this->segment_list_.end();
|
|
++p)
|
|
{
|
|
if ((*p)->type() == elfcpp::PT_LOAD
|
|
&& ((*p)->flags() & elfcpp::PF_R) != 0
|
|
&& (parameters->options().omagic()
|
|
|| ((*p)->flags() & elfcpp::PF_W) == 0))
|
|
return *p;
|
|
}
|
|
|
|
gold_assert(!this->script_options_->saw_phdrs_clause());
|
|
|
|
Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD,
|
|
elfcpp::PF_R);
|
|
return load_seg;
|
|
}
|
|
|
|
// Finalize the layout. When this is called, we have created all the
|
|
// output sections and all the output segments which are based on
|
|
// input sections. We have several things to do, and we have to do
|
|
// them in the right order, so that we get the right results correctly
|
|
// and efficiently.
|
|
|
|
// 1) Finalize the list of output segments and create the segment
|
|
// table header.
|
|
|
|
// 2) Finalize the dynamic symbol table and associated sections.
|
|
|
|
// 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* target, const Task* task)
|
|
{
|
|
target->finalize_sections(this);
|
|
|
|
this->count_local_symbols(task, input_objects);
|
|
|
|
this->link_stabs_sections();
|
|
|
|
Output_segment* phdr_seg = NULL;
|
|
if (!parameters->options().relocatable() && !parameters->doing_static_link())
|
|
{
|
|
// 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.
|
|
if (!this->script_options_->saw_phdrs_clause())
|
|
phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);
|
|
|
|
// 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->script_options()->version_script_info(),
|
|
&this->dynpool_);
|
|
this->create_dynamic_symtab(input_objects, 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.
|
|
if (!parameters->options().shared())
|
|
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, symtab, local_dynamic_count,
|
|
dynamic_symbols, dynstr);
|
|
}
|
|
|
|
if (this->incremental_inputs_)
|
|
{
|
|
this->incremental_inputs_->finalize();
|
|
this->create_incremental_info_sections();
|
|
}
|
|
|
|
// If there is a SECTIONS clause, put all the input sections into
|
|
// the required order.
|
|
Output_segment* load_seg;
|
|
if (this->script_options_->saw_sections_clause())
|
|
load_seg = this->set_section_addresses_from_script(symtab);
|
|
else if (parameters->options().relocatable())
|
|
load_seg = NULL;
|
|
else
|
|
load_seg = this->find_first_load_seg();
|
|
|
|
if (parameters->options().oformat_enum()
|
|
!= General_options::OBJECT_FORMAT_ELF)
|
|
load_seg = NULL;
|
|
|
|
gold_assert(phdr_seg == NULL || load_seg != NULL);
|
|
|
|
// Lay out the segment headers.
|
|
Output_segment_headers* segment_headers;
|
|
if (parameters->options().relocatable())
|
|
segment_headers = NULL;
|
|
else
|
|
{
|
|
segment_headers = new Output_segment_headers(this->segment_list_);
|
|
if (load_seg != NULL)
|
|
load_seg->add_initial_output_data(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,
|
|
parameters->options().entry());
|
|
if (load_seg != NULL)
|
|
load_seg->add_initial_output_data(file_header);
|
|
|
|
this->special_output_list_.push_back(file_header);
|
|
if (segment_headers != NULL)
|
|
this->special_output_list_.push_back(segment_headers);
|
|
|
|
if (this->script_options_->saw_phdrs_clause()
|
|
&& !parameters->options().relocatable())
|
|
{
|
|
// Support use of FILEHDRS and PHDRS attachments in a PHDRS
|
|
// clause in a linker script.
|
|
Script_sections* ss = this->script_options_->script_sections();
|
|
ss->put_headers_in_phdrs(file_header, segment_headers);
|
|
}
|
|
|
|
// We set the output section indexes in set_segment_offsets and
|
|
// set_section_indexes.
|
|
unsigned int shndx = 1;
|
|
|
|
// Set the file offsets of all the segments, and all the sections
|
|
// they contain.
|
|
off_t off;
|
|
if (!parameters->options().relocatable())
|
|
off = this->set_segment_offsets(target, load_seg, &shndx);
|
|
else
|
|
off = this->set_relocatable_section_offsets(file_header, &shndx);
|
|
|
|
// Set the file offsets of all the non-data sections we've seen so
|
|
// far which don't have to wait for the input sections. We need
|
|
// this in order to finalize local symbols in non-allocated
|
|
// sections.
|
|
off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
|
|
|
|
// Set the section indexes of all unallocated sections seen so far,
|
|
// in case any of them are somehow referenced by a symbol.
|
|
shndx = this->set_section_indexes(shndx);
|
|
|
|
// Create the symbol table sections.
|
|
this->create_symtab_sections(input_objects, symtab, shndx, &off);
|
|
if (!parameters->doing_static_link())
|
|
this->assign_local_dynsym_offsets(input_objects);
|
|
|
|
// Process any symbol assignments from a linker script. This must
|
|
// be called after the symbol table has been finalized.
|
|
this->script_options_->finalize_symbols(symtab, this);
|
|
|
|
// Create the .shstrtab section.
|
|
Output_section* shstrtab_section = this->create_shstrtab();
|
|
|
|
// Set the file offsets of the rest of the non-data sections which
|
|
// don't have to wait for the input sections.
|
|
off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
|
|
|
|
// Now that all sections have been created, set the section indexes
|
|
// for any sections which haven't been done yet.
|
|
shndx = this->set_section_indexes(shndx);
|
|
|
|
// Create the section table header.
|
|
this->create_shdrs(shstrtab_section, &off);
|
|
|
|
// If there are no sections which require postprocessing, we can
|
|
// handle the section names now, and avoid a resize later.
|
|
if (!this->any_postprocessing_sections_)
|
|
off = this->set_section_offsets(off,
|
|
STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
|
|
|
|
file_header->set_section_info(this->section_headers_, shstrtab_section);
|
|
|
|
// Now we know exactly where everything goes in the output file
|
|
// (except for non-allocated sections which require postprocessing).
|
|
Output_data::layout_complete();
|
|
|
|
this->output_file_size_ = off;
|
|
|
|
return off;
|
|
}
|
|
|
|
// Create a note header following the format defined in the ELF ABI.
|
|
// NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
|
|
// of the section to create, DESCSZ is the size of the descriptor.
|
|
// ALLOCATE is true if the section should be allocated in memory.
|
|
// This returns the new note section. It sets *TRAILING_PADDING to
|
|
// the number of trailing zero bytes required.
|
|
|
|
Output_section*
|
|
Layout::create_note(const char* name, int note_type,
|
|
const char* section_name, size_t descsz,
|
|
bool allocate, size_t* trailing_padding)
|
|
{
|
|
// Authorities all agree that the values in a .note field should
|
|
// be aligned on 4-byte boundaries for 32-bit binaries. However,
|
|
// they differ on what the alignment is for 64-bit binaries.
|
|
// The GABI says unambiguously they take 8-byte alignment:
|
|
// http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
|
|
// Other documentation says alignment should always be 4 bytes:
|
|
// http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
|
|
// GNU ld and GNU readelf both support the latter (at least as of
|
|
// version 2.16.91), and glibc always generates the latter for
|
|
// .note.ABI-tag (as of version 1.6), so that's the one we go with
|
|
// here.
|
|
#ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
|
|
const int size = parameters->target().get_size();
|
|
#else
|
|
const int size = 32;
|
|
#endif
|
|
|
|
// The contents of the .note section.
|
|
size_t namesz = strlen(name) + 1;
|
|
size_t aligned_namesz = align_address(namesz, size / 8);
|
|
size_t aligned_descsz = align_address(descsz, size / 8);
|
|
|
|
size_t notehdrsz = 3 * (size / 8) + aligned_namesz;
|
|
|
|
unsigned char* buffer = new unsigned char[notehdrsz];
|
|
memset(buffer, 0, notehdrsz);
|
|
|
|
bool is_big_endian = parameters->target().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);
|
|
|
|
elfcpp::Elf_Xword flags = 0;
|
|
if (allocate)
|
|
flags = elfcpp::SHF_ALLOC;
|
|
Output_section* os = this->choose_output_section(NULL, section_name,
|
|
elfcpp::SHT_NOTE,
|
|
flags, false);
|
|
if (os == NULL)
|
|
return NULL;
|
|
|
|
Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz,
|
|
size / 8,
|
|
"** note header");
|
|
os->add_output_section_data(posd);
|
|
|
|
*trailing_padding = aligned_descsz - descsz;
|
|
|
|
return os;
|
|
}
|
|
|
|
// For an executable or shared library, create a note to record the
|
|
// version of gold used to create the binary.
|
|
|
|
void
|
|
Layout::create_gold_note()
|
|
{
|
|
if (parameters->options().relocatable())
|
|
return;
|
|
|
|
std::string desc = std::string("gold ") + gold::get_version_string();
|
|
|
|
size_t trailing_padding;
|
|
Output_section *os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION,
|
|
".note.gnu.gold-version", desc.size(),
|
|
false, &trailing_padding);
|
|
if (os == NULL)
|
|
return;
|
|
|
|
Output_section_data* posd = new Output_data_const(desc, 4);
|
|
os->add_output_section_data(posd);
|
|
|
|
if (trailing_padding > 0)
|
|
{
|
|
posd = new Output_data_zero_fill(trailing_padding, 0);
|
|
os->add_output_section_data(posd);
|
|
}
|
|
}
|
|
|
|
// Record whether the stack should be executable. This can be set
|
|
// from the command line using the -z execstack or -z noexecstack
|
|
// options. Otherwise, if any input file has a .note.GNU-stack
|
|
// section with the SHF_EXECINSTR flag set, the stack should be
|
|
// executable. Otherwise, if at least one input file a
|
|
// .note.GNU-stack section, and some input file has no .note.GNU-stack
|
|
// section, we use the target default for whether the stack should be
|
|
// executable. Otherwise, we don't generate a stack note. When
|
|
// generating a object file, we create a .note.GNU-stack section with
|
|
// the appropriate marking. When generating an executable or shared
|
|
// library, we create a PT_GNU_STACK segment.
|
|
|
|
void
|
|
Layout::create_executable_stack_info()
|
|
{
|
|
bool is_stack_executable;
|
|
if (parameters->options().is_execstack_set())
|
|
is_stack_executable = parameters->options().is_stack_executable();
|
|
else if (!this->input_with_gnu_stack_note_)
|
|
return;
|
|
else
|
|
{
|
|
if (this->input_requires_executable_stack_)
|
|
is_stack_executable = true;
|
|
else if (this->input_without_gnu_stack_note_)
|
|
is_stack_executable =
|
|
parameters->target().is_default_stack_executable();
|
|
else
|
|
is_stack_executable = false;
|
|
}
|
|
|
|
if (parameters->options().relocatable())
|
|
{
|
|
const char* name = this->namepool_.add(".note.GNU-stack", false, NULL);
|
|
elfcpp::Elf_Xword flags = 0;
|
|
if (is_stack_executable)
|
|
flags |= elfcpp::SHF_EXECINSTR;
|
|
this->make_output_section(name, elfcpp::SHT_PROGBITS, flags);
|
|
}
|
|
else
|
|
{
|
|
if (this->script_options_->saw_phdrs_clause())
|
|
return;
|
|
int flags = elfcpp::PF_R | elfcpp::PF_W;
|
|
if (is_stack_executable)
|
|
flags |= elfcpp::PF_X;
|
|
this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
|
|
}
|
|
}
|
|
|
|
// If --build-id was used, set up the build ID note.
|
|
|
|
void
|
|
Layout::create_build_id()
|
|
{
|
|
if (!parameters->options().user_set_build_id())
|
|
return;
|
|
|
|
const char* style = parameters->options().build_id();
|
|
if (strcmp(style, "none") == 0)
|
|
return;
|
|
|
|
// Set DESCSZ to the size of the note descriptor. When possible,
|
|
// set DESC to the note descriptor contents.
|
|
size_t descsz;
|
|
std::string desc;
|
|
if (strcmp(style, "md5") == 0)
|
|
descsz = 128 / 8;
|
|
else if (strcmp(style, "sha1") == 0)
|
|
descsz = 160 / 8;
|
|
else if (strcmp(style, "uuid") == 0)
|
|
{
|
|
const size_t uuidsz = 128 / 8;
|
|
|
|
char buffer[uuidsz];
|
|
memset(buffer, 0, uuidsz);
|
|
|
|
int descriptor = open_descriptor(-1, "/dev/urandom", O_RDONLY);
|
|
if (descriptor < 0)
|
|
gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
|
|
strerror(errno));
|
|
else
|
|
{
|
|
ssize_t got = ::read(descriptor, buffer, uuidsz);
|
|
release_descriptor(descriptor, true);
|
|
if (got < 0)
|
|
gold_error(_("/dev/urandom: read failed: %s"), strerror(errno));
|
|
else if (static_cast<size_t>(got) != uuidsz)
|
|
gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
|
|
uuidsz, got);
|
|
}
|
|
|
|
desc.assign(buffer, uuidsz);
|
|
descsz = uuidsz;
|
|
}
|
|
else if (strncmp(style, "0x", 2) == 0)
|
|
{
|
|
hex_init();
|
|
const char* p = style + 2;
|
|
while (*p != '\0')
|
|
{
|
|
if (hex_p(p[0]) && hex_p(p[1]))
|
|
{
|
|
char c = (hex_value(p[0]) << 4) | hex_value(p[1]);
|
|
desc += c;
|
|
p += 2;
|
|
}
|
|
else if (*p == '-' || *p == ':')
|
|
++p;
|
|
else
|
|
gold_fatal(_("--build-id argument '%s' not a valid hex number"),
|
|
style);
|
|
}
|
|
descsz = desc.size();
|
|
}
|
|
else
|
|
gold_fatal(_("unrecognized --build-id argument '%s'"), style);
|
|
|
|
// Create the note.
|
|
size_t trailing_padding;
|
|
Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID,
|
|
".note.gnu.build-id", descsz, true,
|
|
&trailing_padding);
|
|
if (os == NULL)
|
|
return;
|
|
|
|
if (!desc.empty())
|
|
{
|
|
// We know the value already, so we fill it in now.
|
|
gold_assert(desc.size() == descsz);
|
|
|
|
Output_section_data* posd = new Output_data_const(desc, 4);
|
|
os->add_output_section_data(posd);
|
|
|
|
if (trailing_padding != 0)
|
|
{
|
|
posd = new Output_data_zero_fill(trailing_padding, 0);
|
|
os->add_output_section_data(posd);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
// We need to compute a checksum after we have completed the
|
|
// link.
|
|
gold_assert(trailing_padding == 0);
|
|
this->build_id_note_ = new Output_data_zero_fill(descsz, 4);
|
|
os->add_output_section_data(this->build_id_note_);
|
|
}
|
|
}
|
|
|
|
// If we have both .stabXX and .stabXXstr sections, then the sh_link
|
|
// field of the former should point to the latter. I'm not sure who
|
|
// started this, but the GNU linker does it, and some tools depend
|
|
// upon it.
|
|
|
|
void
|
|
Layout::link_stabs_sections()
|
|
{
|
|
if (!this->have_stabstr_section_)
|
|
return;
|
|
|
|
for (Section_list::iterator p = this->section_list_.begin();
|
|
p != this->section_list_.end();
|
|
++p)
|
|
{
|
|
if ((*p)->type() != elfcpp::SHT_STRTAB)
|
|
continue;
|
|
|
|
const char* name = (*p)->name();
|
|
if (strncmp(name, ".stab", 5) != 0)
|
|
continue;
|
|
|
|
size_t len = strlen(name);
|
|
if (strcmp(name + len - 3, "str") != 0)
|
|
continue;
|
|
|
|
std::string stab_name(name, len - 3);
|
|
Output_section* stab_sec;
|
|
stab_sec = this->find_output_section(stab_name.c_str());
|
|
if (stab_sec != NULL)
|
|
stab_sec->set_link_section(*p);
|
|
}
|
|
}
|
|
|
|
// Create .gnu_incremental_inputs and .gnu_incremental_strtab sections needed
|
|
// for the next run of incremental linking to check what has changed.
|
|
|
|
void
|
|
Layout::create_incremental_info_sections()
|
|
{
|
|
gold_assert(this->incremental_inputs_ != NULL);
|
|
|
|
// Add the .gnu_incremental_inputs section.
|
|
const char *incremental_inputs_name =
|
|
this->namepool_.add(".gnu_incremental_inputs", false, NULL);
|
|
Output_section* inputs_os =
|
|
this->make_output_section(incremental_inputs_name,
|
|
elfcpp::SHT_GNU_INCREMENTAL_INPUTS, 0);
|
|
Output_section_data* posd =
|
|
this->incremental_inputs_->create_incremental_inputs_section_data();
|
|
inputs_os->add_output_section_data(posd);
|
|
|
|
// Add the .gnu_incremental_strtab section.
|
|
const char *incremental_strtab_name =
|
|
this->namepool_.add(".gnu_incremental_strtab", false, NULL);
|
|
Output_section* strtab_os = this->make_output_section(incremental_strtab_name,
|
|
elfcpp::SHT_STRTAB,
|
|
0);
|
|
Output_data_strtab* strtab_data =
|
|
new Output_data_strtab(this->incremental_inputs_->get_stringpool());
|
|
strtab_os->add_output_section_data(strtab_data);
|
|
|
|
inputs_os->set_link_section(strtab_data);
|
|
}
|
|
|
|
// 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 except for the PT_GNU_RELRO
|
|
// segment, 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
|
|
&& type2 != elfcpp::PT_GNU_RELRO)
|
|
return false;
|
|
if (type2 == elfcpp::PT_TLS
|
|
&& type1 != elfcpp::PT_TLS
|
|
&& type1 != elfcpp::PT_GNU_RELRO)
|
|
return true;
|
|
|
|
// We put the PT_GNU_RELRO segment last, because that is where the
|
|
// dynamic linker expects to find it (as with PT_TLS, this is just
|
|
// for efficiency).
|
|
if (type1 == elfcpp::PT_GNU_RELRO && type2 != elfcpp::PT_GNU_RELRO)
|
|
return false;
|
|
if (type2 == elfcpp::PT_GNU_RELRO && type1 != elfcpp::PT_GNU_RELRO)
|
|
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;
|
|
}
|
|
|
|
// If the addresses are set already, sort by load address.
|
|
if (seg1->are_addresses_set())
|
|
{
|
|
if (!seg2->are_addresses_set())
|
|
return true;
|
|
|
|
unsigned int section_count1 = seg1->output_section_count();
|
|
unsigned int section_count2 = seg2->output_section_count();
|
|
if (section_count1 == 0 && section_count2 > 0)
|
|
return true;
|
|
if (section_count1 > 0 && section_count2 == 0)
|
|
return false;
|
|
|
|
uint64_t paddr1 = seg1->first_section_load_address();
|
|
uint64_t paddr2 = seg2->first_section_load_address();
|
|
if (paddr1 != paddr2)
|
|
return paddr1 < paddr2;
|
|
}
|
|
else if (seg2->are_addresses_set())
|
|
return false;
|
|
|
|
// A segment which holds large data comes after a segment which does
|
|
// not hold large data.
|
|
if (seg1->is_large_data_segment())
|
|
{
|
|
if (!seg2->is_large_data_segment())
|
|
return false;
|
|
}
|
|
else if (seg2->is_large_data_segment())
|
|
return true;
|
|
|
|
// Otherwise, we sort PT_LOAD segments based on the flags. Readonly
|
|
// segments come before writable segments. Then writable segments
|
|
// with data come before writable segments without data. 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_W) != 0
|
|
&& seg1->has_any_data_sections() != seg2->has_any_data_sections())
|
|
return seg1->has_any_data_sections();
|
|
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;
|
|
|
|
// We shouldn't get here--we shouldn't create segments which we
|
|
// can't distinguish.
|
|
gold_unreachable();
|
|
}
|
|
|
|
// Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
|
|
|
|
static off_t
|
|
align_file_offset(off_t off, uint64_t addr, uint64_t abi_pagesize)
|
|
{
|
|
uint64_t unsigned_off = off;
|
|
uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1))
|
|
| (addr & (abi_pagesize - 1)));
|
|
if (aligned_off < unsigned_off)
|
|
aligned_off += abi_pagesize;
|
|
return aligned_off;
|
|
}
|
|
|
|
// 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;
|
|
if (parameters->options().user_set_Ttext())
|
|
addr = parameters->options().Ttext();
|
|
else if (parameters->options().shared())
|
|
addr = 0;
|
|
else
|
|
addr = target->default_text_segment_address();
|
|
off_t off = 0;
|
|
|
|
// If LOAD_SEG is NULL, then the file header and segment headers
|
|
// will not be loadable. But they still need to be at offset 0 in
|
|
// the file. Set their offsets now.
|
|
if (load_seg == NULL)
|
|
{
|
|
for (Data_list::iterator p = this->special_output_list_.begin();
|
|
p != this->special_output_list_.end();
|
|
++p)
|
|
{
|
|
off = align_address(off, (*p)->addralign());
|
|
(*p)->set_address_and_file_offset(0, off);
|
|
off += (*p)->data_size();
|
|
}
|
|
}
|
|
|
|
const bool check_sections = parameters->options().check_sections();
|
|
Output_segment* last_load_segment = NULL;
|
|
|
|
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;
|
|
|
|
bool are_addresses_set = (*p)->are_addresses_set();
|
|
if (are_addresses_set)
|
|
{
|
|
// When it comes to setting file offsets, we care about
|
|
// the physical address.
|
|
addr = (*p)->paddr();
|
|
}
|
|
else if (parameters->options().user_set_Tdata()
|
|
&& ((*p)->flags() & elfcpp::PF_W) != 0
|
|
&& (!parameters->options().user_set_Tbss()
|
|
|| (*p)->has_any_data_sections()))
|
|
{
|
|
addr = parameters->options().Tdata();
|
|
are_addresses_set = true;
|
|
}
|
|
else if (parameters->options().user_set_Tbss()
|
|
&& ((*p)->flags() & elfcpp::PF_W) != 0
|
|
&& !(*p)->has_any_data_sections())
|
|
{
|
|
addr = parameters->options().Tbss();
|
|
are_addresses_set = true;
|
|
}
|
|
|
|
uint64_t orig_addr = addr;
|
|
uint64_t orig_off = off;
|
|
|
|
uint64_t aligned_addr = 0;
|
|
uint64_t abi_pagesize = target->abi_pagesize();
|
|
uint64_t common_pagesize = target->common_pagesize();
|
|
|
|
if (!parameters->options().nmagic()
|
|
&& !parameters->options().omagic())
|
|
(*p)->set_minimum_p_align(common_pagesize);
|
|
|
|
if (!are_addresses_set)
|
|
{
|
|
// 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.
|
|
|
|
addr = align_address(addr, (*p)->maximum_alignment());
|
|
aligned_addr = addr;
|
|
|
|
if (was_readonly && ((*p)->flags() & elfcpp::PF_W) != 0)
|
|
{
|
|
if ((addr & (abi_pagesize - 1)) != 0)
|
|
addr = addr + abi_pagesize;
|
|
}
|
|
|
|
off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
|
|
}
|
|
|
|
if (!parameters->options().nmagic()
|
|
&& !parameters->options().omagic())
|
|
off = align_file_offset(off, addr, abi_pagesize);
|
|
|
|
unsigned int shndx_hold = *pshndx;
|
|
uint64_t new_addr = (*p)->set_section_addresses(this, false, 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 (!are_addresses_set && aligned_addr != addr)
|
|
{
|
|
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);
|
|
addr = align_address(addr, (*p)->maximum_alignment());
|
|
off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
|
|
off = align_file_offset(off, addr, abi_pagesize);
|
|
new_addr = (*p)->set_section_addresses(this, true, addr,
|
|
&off, pshndx);
|
|
}
|
|
}
|
|
|
|
addr = new_addr;
|
|
|
|
if (((*p)->flags() & elfcpp::PF_W) == 0)
|
|
was_readonly = true;
|
|
|
|
// Implement --check-sections. We know that the segments
|
|
// are sorted by LMA.
|
|
if (check_sections && last_load_segment != NULL)
|
|
{
|
|
gold_assert(last_load_segment->paddr() <= (*p)->paddr());
|
|
if (last_load_segment->paddr() + last_load_segment->memsz()
|
|
> (*p)->paddr())
|
|
{
|
|
unsigned long long lb1 = last_load_segment->paddr();
|
|
unsigned long long le1 = lb1 + last_load_segment->memsz();
|
|
unsigned long long lb2 = (*p)->paddr();
|
|
unsigned long long le2 = lb2 + (*p)->memsz();
|
|
gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
|
|
"[0x%llx -> 0x%llx]"),
|
|
lb1, le1, lb2, le2);
|
|
}
|
|
}
|
|
last_load_segment = *p;
|
|
}
|
|
}
|
|
|
|
// 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();
|
|
}
|
|
|
|
// Set the TLS offsets for each section in the PT_TLS segment.
|
|
if (this->tls_segment_ != NULL)
|
|
this->tls_segment_->set_tls_offsets();
|
|
|
|
return off;
|
|
}
|
|
|
|
// Set the offsets of all the allocated sections when doing a
|
|
// relocatable link. This does the same jobs as set_segment_offsets,
|
|
// only for a relocatable link.
|
|
|
|
off_t
|
|
Layout::set_relocatable_section_offsets(Output_data* file_header,
|
|
unsigned int *pshndx)
|
|
{
|
|
off_t off = 0;
|
|
|
|
file_header->set_address_and_file_offset(0, 0);
|
|
off += file_header->data_size();
|
|
|
|
for (Section_list::iterator p = this->section_list_.begin();
|
|
p != this->section_list_.end();
|
|
++p)
|
|
{
|
|
// We skip unallocated sections here, except that group sections
|
|
// have to come first.
|
|
if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0
|
|
&& (*p)->type() != elfcpp::SHT_GROUP)
|
|
continue;
|
|
|
|
off = align_address(off, (*p)->addralign());
|
|
|
|
// The linker script might have set the address.
|
|
if (!(*p)->is_address_valid())
|
|
(*p)->set_address(0);
|
|
(*p)->set_file_offset(off);
|
|
(*p)->finalize_data_size();
|
|
off += (*p)->data_size();
|
|
|
|
(*p)->set_out_shndx(*pshndx);
|
|
++*pshndx;
|
|
}
|
|
|
|
return off;
|
|
}
|
|
|
|
// Set the file offset of all the sections not associated with a
|
|
// segment.
|
|
|
|
off_t
|
|
Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
|
|
{
|
|
for (Section_list::iterator p = this->unattached_section_list_.begin();
|
|
p != this->unattached_section_list_.end();
|
|
++p)
|
|
{
|
|
// The symtab section is handled in create_symtab_sections.
|
|
if (*p == this->symtab_section_)
|
|
continue;
|
|
|
|
// If we've already set the data size, don't set it again.
|
|
if ((*p)->is_offset_valid() && (*p)->is_data_size_valid())
|
|
continue;
|
|
|
|
if (pass == BEFORE_INPUT_SECTIONS_PASS
|
|
&& (*p)->requires_postprocessing())
|
|
{
|
|
(*p)->create_postprocessing_buffer();
|
|
this->any_postprocessing_sections_ = true;
|
|
}
|
|
|
|
if (pass == BEFORE_INPUT_SECTIONS_PASS
|
|
&& (*p)->after_input_sections())
|
|
continue;
|
|
else if (pass == POSTPROCESSING_SECTIONS_PASS
|
|
&& (!(*p)->after_input_sections()
|
|
|| (*p)->type() == elfcpp::SHT_STRTAB))
|
|
continue;
|
|
else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
|
|
&& (!(*p)->after_input_sections()
|
|
|| (*p)->type() != elfcpp::SHT_STRTAB))
|
|
continue;
|
|
|
|
off = align_address(off, (*p)->addralign());
|
|
(*p)->set_file_offset(off);
|
|
(*p)->finalize_data_size();
|
|
off += (*p)->data_size();
|
|
|
|
// At this point the name must be set.
|
|
if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
|
|
this->namepool_.add((*p)->name(), false, NULL);
|
|
}
|
|
return off;
|
|
}
|
|
|
|
// Set the section indexes of all the sections not associated with a
|
|
// segment.
|
|
|
|
unsigned int
|
|
Layout::set_section_indexes(unsigned int shndx)
|
|
{
|
|
for (Section_list::iterator p = this->unattached_section_list_.begin();
|
|
p != this->unattached_section_list_.end();
|
|
++p)
|
|
{
|
|
if (!(*p)->has_out_shndx())
|
|
{
|
|
(*p)->set_out_shndx(shndx);
|
|
++shndx;
|
|
}
|
|
}
|
|
return shndx;
|
|
}
|
|
|
|
// Set the section addresses according to the linker script. This is
|
|
// only called when we see a SECTIONS clause. This returns the
|
|
// program segment which should hold the file header and segment
|
|
// headers, if any. It will return NULL if they should not be in a
|
|
// segment.
|
|
|
|
Output_segment*
|
|
Layout::set_section_addresses_from_script(Symbol_table* symtab)
|
|
{
|
|
Script_sections* ss = this->script_options_->script_sections();
|
|
gold_assert(ss->saw_sections_clause());
|
|
|
|
// Place each orphaned output section in the script.
|
|
for (Section_list::iterator p = this->section_list_.begin();
|
|
p != this->section_list_.end();
|
|
++p)
|
|
{
|
|
if (!(*p)->found_in_sections_clause())
|
|
ss->place_orphan(*p);
|
|
}
|
|
|
|
return this->script_options_->set_section_addresses(symtab, this);
|
|
}
|
|
|
|
// Count the local symbols in the regular symbol table and the dynamic
|
|
// symbol table, and build the respective string pools.
|
|
|
|
void
|
|
Layout::count_local_symbols(const Task* task,
|
|
const Input_objects* input_objects)
|
|
{
|
|
// First, figure out an upper bound on the number of symbols we'll
|
|
// be inserting into each pool. This helps us create the pools with
|
|
// the right size, to avoid unnecessary hashtable resizing.
|
|
unsigned int symbol_count = 0;
|
|
for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
|
|
p != input_objects->relobj_end();
|
|
++p)
|
|
symbol_count += (*p)->local_symbol_count();
|
|
|
|
// Go from "upper bound" to "estimate." We overcount for two
|
|
// reasons: we double-count symbols that occur in more than one
|
|
// object file, and we count symbols that are dropped from the
|
|
// output. Add it all together and assume we overcount by 100%.
|
|
symbol_count /= 2;
|
|
|
|
// We assume all symbols will go into both the sympool and dynpool.
|
|
this->sympool_.reserve(symbol_count);
|
|
this->dynpool_.reserve(symbol_count);
|
|
|
|
for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
|
|
p != input_objects->relobj_end();
|
|
++p)
|
|
{
|
|
Task_lock_obj<Object> tlo(task, *p);
|
|
(*p)->count_local_symbols(&this->sympool_, &this->dynpool_);
|
|
}
|
|
}
|
|
|
|
// 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. SHNUM is the number of sections so far.
|
|
|
|
void
|
|
Layout::create_symtab_sections(const Input_objects* input_objects,
|
|
Symbol_table* symtab,
|
|
unsigned int shnum,
|
|
off_t* poff)
|
|
{
|
|
int symsize;
|
|
unsigned int align;
|
|
if (parameters->target().get_size() == 32)
|
|
{
|
|
symsize = elfcpp::Elf_sizes<32>::sym_size;
|
|
align = 4;
|
|
}
|
|
else if (parameters->target().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)
|
|
{
|
|
unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
|
|
off);
|
|
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(off, dynoff, dyn_global_index, dyncount,
|
|
&this->sympool_, &local_symcount);
|
|
|
|
if (!parameters->options().strip_all())
|
|
{
|
|
this->sympool_.set_string_offsets();
|
|
|
|
const char* symtab_name = this->namepool_.add(".symtab", false, 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_fixed_space(off - startoff,
|
|
align,
|
|
"** symtab");
|
|
osymtab->add_output_section_data(pos);
|
|
|
|
// We generate a .symtab_shndx section if we have more than
|
|
// SHN_LORESERVE sections. Technically it is possible that we
|
|
// don't need one, because it is possible that there are no
|
|
// symbols in any of sections with indexes larger than
|
|
// SHN_LORESERVE. That is probably unusual, though, and it is
|
|
// easier to always create one than to compute section indexes
|
|
// twice (once here, once when writing out the symbols).
|
|
if (shnum >= elfcpp::SHN_LORESERVE)
|
|
{
|
|
const char* symtab_xindex_name = this->namepool_.add(".symtab_shndx",
|
|
false, NULL);
|
|
Output_section* osymtab_xindex =
|
|
this->make_output_section(symtab_xindex_name,
|
|
elfcpp::SHT_SYMTAB_SHNDX, 0);
|
|
|
|
size_t symcount = (off - startoff) / symsize;
|
|
this->symtab_xindex_ = new Output_symtab_xindex(symcount);
|
|
|
|
osymtab_xindex->add_output_section_data(this->symtab_xindex_);
|
|
|
|
osymtab_xindex->set_link_section(osymtab);
|
|
osymtab_xindex->set_addralign(4);
|
|
osymtab_xindex->set_entsize(4);
|
|
|
|
osymtab_xindex->set_after_input_sections();
|
|
|
|
// This tells the driver code to wait until the symbol table
|
|
// has written out before writing out the postprocessing
|
|
// sections, including the .symtab_shndx section.
|
|
this->any_postprocessing_sections_ = true;
|
|
}
|
|
|
|
const char* strtab_name = this->namepool_.add(".strtab", false, 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_file_offset(startoff);
|
|
osymtab->finalize_data_size();
|
|
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", false, NULL);
|
|
|
|
Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0);
|
|
|
|
// We can't write out this section until we've set all the section
|
|
// names, and we don't set the names of compressed output sections
|
|
// until relocations are complete.
|
|
os->set_after_input_sections();
|
|
|
|
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.
|
|
|
|
void
|
|
Layout::create_shdrs(const Output_section* shstrtab_section, off_t* poff)
|
|
{
|
|
Output_section_headers* oshdrs;
|
|
oshdrs = new Output_section_headers(this,
|
|
&this->segment_list_,
|
|
&this->section_list_,
|
|
&this->unattached_section_list_,
|
|
&this->namepool_,
|
|
shstrtab_section);
|
|
off_t off = align_address(*poff, oshdrs->addralign());
|
|
oshdrs->set_address_and_file_offset(0, off);
|
|
off += oshdrs->data_size();
|
|
*poff = off;
|
|
this->section_headers_ = oshdrs;
|
|
}
|
|
|
|
// Count the allocated sections.
|
|
|
|
size_t
|
|
Layout::allocated_output_section_count() const
|
|
{
|
|
size_t section_count = 0;
|
|
for (Segment_list::const_iterator p = this->segment_list_.begin();
|
|
p != this->segment_list_.end();
|
|
++p)
|
|
section_count += (*p)->output_section_count();
|
|
return section_count;
|
|
}
|
|
|
|
// Create the dynamic symbol table.
|
|
|
|
void
|
|
Layout::create_dynamic_symtab(const Input_objects* input_objects,
|
|
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;
|
|
}
|
|
}
|
|
|
|
// Count the local symbols that need to go in the dynamic symbol table,
|
|
// and set the dynamic symbol indexes.
|
|
for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
|
|
p != input_objects->relobj_end();
|
|
++p)
|
|
{
|
|
unsigned int new_index = (*p)->set_local_dynsym_indexes(index);
|
|
index = new_index;
|
|
}
|
|
|
|
unsigned int local_symcount = index;
|
|
*plocal_dynamic_count = local_symcount;
|
|
|
|
index = symtab->set_dynsym_indexes(index, pdynamic_symbols,
|
|
&this->dynpool_, pversions);
|
|
|
|
int symsize;
|
|
unsigned int align;
|
|
const int size = parameters->target().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.
|
|
|
|
Output_section* dynsym = this->choose_output_section(NULL, ".dynsym",
|
|
elfcpp::SHT_DYNSYM,
|
|
elfcpp::SHF_ALLOC,
|
|
false);
|
|
|
|
Output_section_data* odata = new Output_data_fixed_space(index * symsize,
|
|
align,
|
|
"** dynsym");
|
|
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);
|
|
|
|
// If there are more than SHN_LORESERVE allocated sections, we
|
|
// create a .dynsym_shndx section. It is possible that we don't
|
|
// need one, because it is possible that there are no dynamic
|
|
// symbols in any of the sections with indexes larger than
|
|
// SHN_LORESERVE. This is probably unusual, though, and at this
|
|
// time we don't know the actual section indexes so it is
|
|
// inconvenient to check.
|
|
if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE)
|
|
{
|
|
Output_section* dynsym_xindex =
|
|
this->choose_output_section(NULL, ".dynsym_shndx",
|
|
elfcpp::SHT_SYMTAB_SHNDX,
|
|
elfcpp::SHF_ALLOC,
|
|
false);
|
|
|
|
this->dynsym_xindex_ = new Output_symtab_xindex(index);
|
|
|
|
dynsym_xindex->add_output_section_data(this->dynsym_xindex_);
|
|
|
|
dynsym_xindex->set_link_section(dynsym);
|
|
dynsym_xindex->set_addralign(4);
|
|
dynsym_xindex->set_entsize(4);
|
|
|
|
dynsym_xindex->set_after_input_sections();
|
|
|
|
// This tells the driver code to wait until the symbol table has
|
|
// written out before writing out the postprocessing sections,
|
|
// including the .dynsym_shndx section.
|
|
this->any_postprocessing_sections_ = true;
|
|
}
|
|
|
|
// Create the dynamic string table section.
|
|
|
|
Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
|
|
elfcpp::SHT_STRTAB,
|
|
elfcpp::SHF_ALLOC,
|
|
false);
|
|
|
|
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.
|
|
|
|
if (strcmp(parameters->options().hash_style(), "sysv") == 0
|
|
|| strcmp(parameters->options().hash_style(), "both") == 0)
|
|
{
|
|
unsigned char* phash;
|
|
unsigned int hashlen;
|
|
Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
|
|
&phash, &hashlen);
|
|
|
|
Output_section* hashsec = this->choose_output_section(NULL, ".hash",
|
|
elfcpp::SHT_HASH,
|
|
elfcpp::SHF_ALLOC,
|
|
false);
|
|
|
|
Output_section_data* hashdata = new Output_data_const_buffer(phash,
|
|
hashlen,
|
|
align,
|
|
"** hash");
|
|
hashsec->add_output_section_data(hashdata);
|
|
|
|
hashsec->set_link_section(dynsym);
|
|
hashsec->set_entsize(4);
|
|
|
|
odyn->add_section_address(elfcpp::DT_HASH, hashsec);
|
|
}
|
|
|
|
if (strcmp(parameters->options().hash_style(), "gnu") == 0
|
|
|| strcmp(parameters->options().hash_style(), "both") == 0)
|
|
{
|
|
unsigned char* phash;
|
|
unsigned int hashlen;
|
|
Dynobj::create_gnu_hash_table(*pdynamic_symbols, local_symcount,
|
|
&phash, &hashlen);
|
|
|
|
Output_section* hashsec = this->choose_output_section(NULL, ".gnu.hash",
|
|
elfcpp::SHT_GNU_HASH,
|
|
elfcpp::SHF_ALLOC,
|
|
false);
|
|
|
|
Output_section_data* hashdata = new Output_data_const_buffer(phash,
|
|
hashlen,
|
|
align,
|
|
"** hash");
|
|
hashsec->add_output_section_data(hashdata);
|
|
|
|
hashsec->set_link_section(dynsym);
|
|
hashsec->set_entsize(4);
|
|
|
|
odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec);
|
|
}
|
|
}
|
|
|
|
// Assign offsets to each local portion of the dynamic symbol table.
|
|
|
|
void
|
|
Layout::assign_local_dynsym_offsets(const Input_objects* input_objects)
|
|
{
|
|
Output_section* dynsym = this->dynsym_section_;
|
|
gold_assert(dynsym != NULL);
|
|
|
|
off_t off = dynsym->offset();
|
|
|
|
// Skip the dummy symbol at the start of the section.
|
|
off += dynsym->entsize();
|
|
|
|
for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
|
|
p != input_objects->relobj_end();
|
|
++p)
|
|
{
|
|
unsigned int count = (*p)->set_local_dynsym_offset(off);
|
|
off += count * dynsym->entsize();
|
|
}
|
|
}
|
|
|
|
// Create the version sections.
|
|
|
|
void
|
|
Layout::create_version_sections(const Versions* versions,
|
|
const Symbol_table* symtab,
|
|
unsigned int local_symcount,
|
|
const std::vector<Symbol*>& dynamic_symbols,
|
|
const Output_section* dynstr)
|
|
{
|
|
if (!versions->any_defs() && !versions->any_needs())
|
|
return;
|
|
|
|
switch (parameters->size_and_endianness())
|
|
{
|
|
#ifdef HAVE_TARGET_32_LITTLE
|
|
case Parameters::TARGET_32_LITTLE:
|
|
this->sized_create_version_sections<32, false>(versions, symtab,
|
|
local_symcount,
|
|
dynamic_symbols, dynstr);
|
|
break;
|
|
#endif
|
|
#ifdef HAVE_TARGET_32_BIG
|
|
case Parameters::TARGET_32_BIG:
|
|
this->sized_create_version_sections<32, true>(versions, symtab,
|
|
local_symcount,
|
|
dynamic_symbols, dynstr);
|
|
break;
|
|
#endif
|
|
#ifdef HAVE_TARGET_64_LITTLE
|
|
case Parameters::TARGET_64_LITTLE:
|
|
this->sized_create_version_sections<64, false>(versions, symtab,
|
|
local_symcount,
|
|
dynamic_symbols, dynstr);
|
|
break;
|
|
#endif
|
|
#ifdef HAVE_TARGET_64_BIG
|
|
case Parameters::TARGET_64_BIG:
|
|
this->sized_create_version_sections<64, true>(versions, symtab,
|
|
local_symcount,
|
|
dynamic_symbols, dynstr);
|
|
break;
|
|
#endif
|
|
default:
|
|
gold_unreachable();
|
|
}
|
|
}
|
|
|
|
// Create the version sections, sized version.
|
|
|
|
template<int size, bool big_endian>
|
|
void
|
|
Layout::sized_create_version_sections(
|
|
const Versions* versions,
|
|
const Symbol_table* symtab,
|
|
unsigned int local_symcount,
|
|
const std::vector<Symbol*>& dynamic_symbols,
|
|
const Output_section* dynstr)
|
|
{
|
|
Output_section* vsec = this->choose_output_section(NULL, ".gnu.version",
|
|
elfcpp::SHT_GNU_versym,
|
|
elfcpp::SHF_ALLOC,
|
|
false);
|
|
|
|
unsigned char* vbuf;
|
|
unsigned int vsize;
|
|
versions->symbol_section_contents<size, big_endian>(symtab, &this->dynpool_,
|
|
local_symcount,
|
|
dynamic_symbols,
|
|
&vbuf, &vsize);
|
|
|
|
Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2,
|
|
"** versions");
|
|
|
|
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())
|
|
{
|
|
Output_section* vdsec;
|
|
vdsec= this->choose_output_section(NULL, ".gnu.version_d",
|
|
elfcpp::SHT_GNU_verdef,
|
|
elfcpp::SHF_ALLOC,
|
|
false);
|
|
|
|
unsigned char* vdbuf;
|
|
unsigned int vdsize;
|
|
unsigned int vdentries;
|
|
versions->def_section_contents<size, big_endian>(&this->dynpool_, &vdbuf,
|
|
&vdsize, &vdentries);
|
|
|
|
Output_section_data* vddata =
|
|
new Output_data_const_buffer(vdbuf, vdsize, 4, "** version defs");
|
|
|
|
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())
|
|
{
|
|
Output_section* vnsec;
|
|
vnsec = this->choose_output_section(NULL, ".gnu.version_r",
|
|
elfcpp::SHT_GNU_verneed,
|
|
elfcpp::SHF_ALLOC,
|
|
false);
|
|
|
|
unsigned char* vnbuf;
|
|
unsigned int vnsize;
|
|
unsigned int vnentries;
|
|
versions->need_section_contents<size, big_endian>(&this->dynpool_,
|
|
&vnbuf, &vnsize,
|
|
&vnentries);
|
|
|
|
Output_section_data* vndata =
|
|
new Output_data_const_buffer(vnbuf, vnsize, 4, "** version refs");
|
|
|
|
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 = parameters->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);
|
|
|
|
Output_section* osec = this->choose_output_section(NULL, ".interp",
|
|
elfcpp::SHT_PROGBITS,
|
|
elfcpp::SHF_ALLOC,
|
|
false);
|
|
osec->add_output_section_data(odata);
|
|
|
|
if (!this->script_options_->saw_phdrs_clause())
|
|
{
|
|
Output_segment* oseg = this->make_output_segment(elfcpp::PT_INTERP,
|
|
elfcpp::PF_R);
|
|
oseg->add_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)
|
|
{
|
|
if (!this->script_options_->saw_phdrs_clause())
|
|
{
|
|
Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC,
|
|
(elfcpp::PF_R
|
|
| elfcpp::PF_W));
|
|
oseg->add_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());
|
|
}
|
|
|
|
if (parameters->options().shared())
|
|
{
|
|
const char* soname = parameters->options().soname();
|
|
if (soname != NULL)
|
|
odyn->add_string(elfcpp::DT_SONAME, 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(parameters->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);
|
|
if (parameters->options().enable_new_dtags())
|
|
odyn->add_string(elfcpp::DT_RUNPATH, rpath_val);
|
|
}
|
|
|
|
// Look for text segments that have dynamic relocations.
|
|
bool have_textrel = false;
|
|
if (!this->script_options_->saw_sections_clause())
|
|
{
|
|
for (Segment_list::const_iterator p = this->segment_list_.begin();
|
|
p != this->segment_list_.end();
|
|
++p)
|
|
{
|
|
if (((*p)->flags() & elfcpp::PF_W) == 0
|
|
&& (*p)->dynamic_reloc_count() > 0)
|
|
{
|
|
have_textrel = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
else
|
|
{
|
|
// We don't know the section -> segment mapping, so we are
|
|
// conservative and just look for readonly sections with
|
|
// relocations. If those sections wind up in writable segments,
|
|
// then we have created an unnecessary DT_TEXTREL entry.
|
|
for (Section_list::const_iterator p = this->section_list_.begin();
|
|
p != this->section_list_.end();
|
|
++p)
|
|
{
|
|
if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
|
|
&& ((*p)->flags() & elfcpp::SHF_WRITE) == 0
|
|
&& ((*p)->dynamic_reloc_count() > 0))
|
|
{
|
|
have_textrel = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Add a DT_FLAGS entry. We add it even if no flags are set so that
|
|
// post-link tools can easily modify these flags if desired.
|
|
unsigned int flags = 0;
|
|
if (have_textrel)
|
|
{
|
|
// Add a DT_TEXTREL for compatibility with older loaders.
|
|
odyn->add_constant(elfcpp::DT_TEXTREL, 0);
|
|
flags |= elfcpp::DF_TEXTREL;
|
|
}
|
|
if (parameters->options().shared() && this->has_static_tls())
|
|
flags |= elfcpp::DF_STATIC_TLS;
|
|
if (parameters->options().origin())
|
|
flags |= elfcpp::DF_ORIGIN;
|
|
if (parameters->options().now())
|
|
flags |= elfcpp::DF_BIND_NOW;
|
|
odyn->add_constant(elfcpp::DT_FLAGS, flags);
|
|
|
|
flags = 0;
|
|
if (parameters->options().initfirst())
|
|
flags |= elfcpp::DF_1_INITFIRST;
|
|
if (parameters->options().interpose())
|
|
flags |= elfcpp::DF_1_INTERPOSE;
|
|
if (parameters->options().loadfltr())
|
|
flags |= elfcpp::DF_1_LOADFLTR;
|
|
if (parameters->options().nodefaultlib())
|
|
flags |= elfcpp::DF_1_NODEFLIB;
|
|
if (parameters->options().nodelete())
|
|
flags |= elfcpp::DF_1_NODELETE;
|
|
if (parameters->options().nodlopen())
|
|
flags |= elfcpp::DF_1_NOOPEN;
|
|
if (parameters->options().nodump())
|
|
flags |= elfcpp::DF_1_NODUMP;
|
|
if (!parameters->options().shared())
|
|
flags &= ~(elfcpp::DF_1_INITFIRST
|
|
| elfcpp::DF_1_NODELETE
|
|
| elfcpp::DF_1_NOOPEN);
|
|
if (parameters->options().origin())
|
|
flags |= elfcpp::DF_1_ORIGIN;
|
|
if (parameters->options().now())
|
|
flags |= elfcpp::DF_1_NOW;
|
|
if (flags)
|
|
odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
|
|
}
|
|
|
|
// The mapping of input section name prefixes to output section names.
|
|
// In some cases one prefix is itself a prefix of another prefix; in
|
|
// such a case the longer prefix must come first. These prefixes are
|
|
// based on the GNU linker default ELF linker script.
|
|
|
|
#define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
|
|
const Layout::Section_name_mapping Layout::section_name_mapping[] =
|
|
{
|
|
MAPPING_INIT(".text.", ".text"),
|
|
MAPPING_INIT(".ctors.", ".ctors"),
|
|
MAPPING_INIT(".dtors.", ".dtors"),
|
|
MAPPING_INIT(".rodata.", ".rodata"),
|
|
MAPPING_INIT(".data.rel.ro.local", ".data.rel.ro.local"),
|
|
MAPPING_INIT(".data.rel.ro", ".data.rel.ro"),
|
|
MAPPING_INIT(".data.", ".data"),
|
|
MAPPING_INIT(".bss.", ".bss"),
|
|
MAPPING_INIT(".tdata.", ".tdata"),
|
|
MAPPING_INIT(".tbss.", ".tbss"),
|
|
MAPPING_INIT(".init_array.", ".init_array"),
|
|
MAPPING_INIT(".fini_array.", ".fini_array"),
|
|
MAPPING_INIT(".sdata.", ".sdata"),
|
|
MAPPING_INIT(".sbss.", ".sbss"),
|
|
// FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
|
|
// differently depending on whether it is creating a shared library.
|
|
MAPPING_INIT(".sdata2.", ".sdata"),
|
|
MAPPING_INIT(".sbss2.", ".sbss"),
|
|
MAPPING_INIT(".lrodata.", ".lrodata"),
|
|
MAPPING_INIT(".ldata.", ".ldata"),
|
|
MAPPING_INIT(".lbss.", ".lbss"),
|
|
MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
|
|
MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
|
|
MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
|
|
MAPPING_INIT(".gnu.linkonce.t.", ".text"),
|
|
MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
|
|
MAPPING_INIT(".gnu.linkonce.d.", ".data"),
|
|
MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
|
|
MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
|
|
MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
|
|
MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
|
|
MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
|
|
MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
|
|
MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
|
|
MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
|
|
MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
|
|
MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
|
|
MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
|
|
MAPPING_INIT(".ARM.extab.", ".ARM.extab"),
|
|
MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
|
|
MAPPING_INIT(".ARM.exidx.", ".ARM.exidx"),
|
|
MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
|
|
};
|
|
#undef MAPPING_INIT
|
|
|
|
const int Layout::section_name_mapping_count =
|
|
(sizeof(Layout::section_name_mapping)
|
|
/ sizeof(Layout::section_name_mapping[0]));
|
|
|
|
// 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)
|
|
{
|
|
// gcc 4.3 generates the following sorts of section names when it
|
|
// needs a section name specific to a function:
|
|
// .text.FN
|
|
// .rodata.FN
|
|
// .sdata2.FN
|
|
// .data.FN
|
|
// .data.rel.FN
|
|
// .data.rel.local.FN
|
|
// .data.rel.ro.FN
|
|
// .data.rel.ro.local.FN
|
|
// .sdata.FN
|
|
// .bss.FN
|
|
// .sbss.FN
|
|
// .tdata.FN
|
|
// .tbss.FN
|
|
|
|
// The GNU linker maps all of those to the part before the .FN,
|
|
// except that .data.rel.local.FN is mapped to .data, and
|
|
// .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
|
|
// beginning with .data.rel.ro.local are grouped together.
|
|
|
|
// For an anonymous namespace, the string FN can contain a '.'.
|
|
|
|
// Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
|
|
// GNU linker maps to .rodata.
|
|
|
|
// The .data.rel.ro sections are used with -z relro. The sections
|
|
// are recognized by name. We use the same names that the GNU
|
|
// linker does for these sections.
|
|
|
|
// It is hard to handle this in a principled way, so we don't even
|
|
// try. We use a table of mappings. If the input section name is
|
|
// not found in the table, we simply use it as the output section
|
|
// name.
|
|
|
|
const Section_name_mapping* psnm = section_name_mapping;
|
|
for (int i = 0; i < section_name_mapping_count; ++i, ++psnm)
|
|
{
|
|
if (strncmp(name, psnm->from, psnm->fromlen) == 0)
|
|
{
|
|
*plen = psnm->tolen;
|
|
return psnm->to;
|
|
}
|
|
}
|
|
|
|
return name;
|
|
}
|
|
|
|
// Check if a comdat group or .gnu.linkonce section with the given
|
|
// NAME is selected for the link. If there is already a section,
|
|
// *KEPT_SECTION is set to point to the existing section and the
|
|
// function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
|
|
// IS_GROUP_NAME are recorded for this NAME in the layout object,
|
|
// *KEPT_SECTION is set to the internal copy and the function returns
|
|
// true.
|
|
|
|
bool
|
|
Layout::find_or_add_kept_section(const std::string& name,
|
|
Relobj* object,
|
|
unsigned int shndx,
|
|
bool is_comdat,
|
|
bool is_group_name,
|
|
Kept_section** kept_section)
|
|
{
|
|
// It's normal to see a couple of entries here, for the x86 thunk
|
|
// sections. If we see more than a few, we're linking a C++
|
|
// program, and we resize to get more space to minimize rehashing.
|
|
if (this->signatures_.size() > 4
|
|
&& !this->resized_signatures_)
|
|
{
|
|
reserve_unordered_map(&this->signatures_,
|
|
this->number_of_input_files_ * 64);
|
|
this->resized_signatures_ = true;
|
|
}
|
|
|
|
Kept_section candidate;
|
|
std::pair<Signatures::iterator, bool> ins =
|
|
this->signatures_.insert(std::make_pair(name, candidate));
|
|
|
|
if (kept_section != NULL)
|
|
*kept_section = &ins.first->second;
|
|
if (ins.second)
|
|
{
|
|
// This is the first time we've seen this signature.
|
|
ins.first->second.set_object(object);
|
|
ins.first->second.set_shndx(shndx);
|
|
if (is_comdat)
|
|
ins.first->second.set_is_comdat();
|
|
if (is_group_name)
|
|
ins.first->second.set_is_group_name();
|
|
return true;
|
|
}
|
|
|
|
// We have already seen this signature.
|
|
|
|
if (ins.first->second.is_group_name())
|
|
{
|
|
// We've already seen a real section group with this signature.
|
|
// If the kept group is from a plugin object, and we're in the
|
|
// replacement phase, accept the new one as a replacement.
|
|
if (ins.first->second.object() == NULL
|
|
&& parameters->options().plugins()->in_replacement_phase())
|
|
{
|
|
ins.first->second.set_object(object);
|
|
ins.first->second.set_shndx(shndx);
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
else if (is_group_name)
|
|
{
|
|
// 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.set_is_group_name();
|
|
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;
|
|
}
|
|
}
|
|
|
|
// Store the allocated sections into the section list.
|
|
|
|
void
|
|
Layout::get_allocated_sections(Section_list* section_list) const
|
|
{
|
|
for (Section_list::const_iterator p = this->section_list_.begin();
|
|
p != this->section_list_.end();
|
|
++p)
|
|
if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
|
|
section_list->push_back(*p);
|
|
}
|
|
|
|
// Create an output segment.
|
|
|
|
Output_segment*
|
|
Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
|
|
{
|
|
gold_assert(!parameters->options().relocatable());
|
|
Output_segment* oseg = new Output_segment(type, flags);
|
|
this->segment_list_.push_back(oseg);
|
|
|
|
if (type == elfcpp::PT_TLS)
|
|
this->tls_segment_ = oseg;
|
|
else if (type == elfcpp::PT_GNU_RELRO)
|
|
this->relro_segment_ = oseg;
|
|
|
|
return oseg;
|
|
}
|
|
|
|
// 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.
|
|
|
|
void
|
|
Layout::write_output_sections(Output_file* of) const
|
|
{
|
|
for (Section_list::const_iterator p = this->section_list_.begin();
|
|
p != this->section_list_.end();
|
|
++p)
|
|
{
|
|
if (!(*p)->after_input_sections())
|
|
(*p)->write(of);
|
|
}
|
|
}
|
|
|
|
// 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->options().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, this->symtab_xindex_, 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, this->dynsym_xindex_, of, off);
|
|
}
|
|
}
|
|
|
|
// 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 out the Output_sections which can only be written after the
|
|
// input sections are complete.
|
|
|
|
void
|
|
Layout::write_sections_after_input_sections(Output_file* of)
|
|
{
|
|
// Determine the final section offsets, and thus the final output
|
|
// file size. Note we finalize the .shstrab last, to allow the
|
|
// after_input_section sections to modify their section-names before
|
|
// writing.
|
|
if (this->any_postprocessing_sections_)
|
|
{
|
|
off_t off = this->output_file_size_;
|
|
off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS);
|
|
|
|
// Now that we've finalized the names, we can finalize the shstrab.
|
|
off =
|
|
this->set_section_offsets(off,
|
|
STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
|
|
|
|
if (off > this->output_file_size_)
|
|
{
|
|
of->resize(off);
|
|
this->output_file_size_ = off;
|
|
}
|
|
}
|
|
|
|
for (Section_list::const_iterator p = this->section_list_.begin();
|
|
p != this->section_list_.end();
|
|
++p)
|
|
{
|
|
if ((*p)->after_input_sections())
|
|
(*p)->write(of);
|
|
}
|
|
|
|
this->section_headers_->write(of);
|
|
}
|
|
|
|
// If the build ID requires computing a checksum, do so here, and
|
|
// write it out. We compute a checksum over the entire file because
|
|
// that is simplest.
|
|
|
|
void
|
|
Layout::write_build_id(Output_file* of) const
|
|
{
|
|
if (this->build_id_note_ == NULL)
|
|
return;
|
|
|
|
const unsigned char* iv = of->get_input_view(0, this->output_file_size_);
|
|
|
|
unsigned char* ov = of->get_output_view(this->build_id_note_->offset(),
|
|
this->build_id_note_->data_size());
|
|
|
|
const char* style = parameters->options().build_id();
|
|
if (strcmp(style, "sha1") == 0)
|
|
{
|
|
sha1_ctx ctx;
|
|
sha1_init_ctx(&ctx);
|
|
sha1_process_bytes(iv, this->output_file_size_, &ctx);
|
|
sha1_finish_ctx(&ctx, ov);
|
|
}
|
|
else if (strcmp(style, "md5") == 0)
|
|
{
|
|
md5_ctx ctx;
|
|
md5_init_ctx(&ctx);
|
|
md5_process_bytes(iv, this->output_file_size_, &ctx);
|
|
md5_finish_ctx(&ctx, ov);
|
|
}
|
|
else
|
|
gold_unreachable();
|
|
|
|
of->write_output_view(this->build_id_note_->offset(),
|
|
this->build_id_note_->data_size(),
|
|
ov);
|
|
|
|
of->free_input_view(0, this->output_file_size_, iv);
|
|
}
|
|
|
|
// Write out a binary file. This is called after the link is
|
|
// complete. IN is the temporary output file we used to generate the
|
|
// ELF code. We simply walk through the segments, read them from
|
|
// their file offset in IN, and write them to their load address in
|
|
// the output file. FIXME: with a bit more work, we could support
|
|
// S-records and/or Intel hex format here.
|
|
|
|
void
|
|
Layout::write_binary(Output_file* in) const
|
|
{
|
|
gold_assert(parameters->options().oformat_enum()
|
|
== General_options::OBJECT_FORMAT_BINARY);
|
|
|
|
// Get the size of the binary file.
|
|
uint64_t max_load_address = 0;
|
|
for (Segment_list::const_iterator p = this->segment_list_.begin();
|
|
p != this->segment_list_.end();
|
|
++p)
|
|
{
|
|
if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
|
|
{
|
|
uint64_t max_paddr = (*p)->paddr() + (*p)->filesz();
|
|
if (max_paddr > max_load_address)
|
|
max_load_address = max_paddr;
|
|
}
|
|
}
|
|
|
|
Output_file out(parameters->options().output_file_name());
|
|
out.open(max_load_address);
|
|
|
|
for (Segment_list::const_iterator p = this->segment_list_.begin();
|
|
p != this->segment_list_.end();
|
|
++p)
|
|
{
|
|
if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
|
|
{
|
|
const unsigned char* vin = in->get_input_view((*p)->offset(),
|
|
(*p)->filesz());
|
|
unsigned char* vout = out.get_output_view((*p)->paddr(),
|
|
(*p)->filesz());
|
|
memcpy(vout, vin, (*p)->filesz());
|
|
out.write_output_view((*p)->paddr(), (*p)->filesz(), vout);
|
|
in->free_input_view((*p)->offset(), (*p)->filesz(), vin);
|
|
}
|
|
}
|
|
|
|
out.close();
|
|
}
|
|
|
|
// Print the output sections to the map file.
|
|
|
|
void
|
|
Layout::print_to_mapfile(Mapfile* mapfile) const
|
|
{
|
|
for (Segment_list::const_iterator p = this->segment_list_.begin();
|
|
p != this->segment_list_.end();
|
|
++p)
|
|
(*p)->print_sections_to_mapfile(mapfile);
|
|
}
|
|
|
|
// Print statistical information to stderr. This is used for --stats.
|
|
|
|
void
|
|
Layout::print_stats() const
|
|
{
|
|
this->namepool_.print_stats("section name pool");
|
|
this->sympool_.print_stats("output symbol name pool");
|
|
this->dynpool_.print_stats("dynamic name pool");
|
|
|
|
for (Section_list::const_iterator p = this->section_list_.begin();
|
|
p != this->section_list_.end();
|
|
++p)
|
|
(*p)->print_merge_stats();
|
|
}
|
|
|
|
// Write_sections_task methods.
|
|
|
|
// We can always run this task.
|
|
|
|
Task_token*
|
|
Write_sections_task::is_runnable()
|
|
{
|
|
return NULL;
|
|
}
|
|
|
|
// We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
|
|
// when finished.
|
|
|
|
void
|
|
Write_sections_task::locks(Task_locker* tl)
|
|
{
|
|
tl->add(this, this->output_sections_blocker_);
|
|
tl->add(this, this->final_blocker_);
|
|
}
|
|
|
|
// Run the task--write out the data.
|
|
|
|
void
|
|
Write_sections_task::run(Workqueue*)
|
|
{
|
|
this->layout_->write_output_sections(this->of_);
|
|
}
|
|
|
|
// Write_data_task methods.
|
|
|
|
// We can always run this task.
|
|
|
|
Task_token*
|
|
Write_data_task::is_runnable()
|
|
{
|
|
return NULL;
|
|
}
|
|
|
|
// We need to unlock FINAL_BLOCKER when finished.
|
|
|
|
void
|
|
Write_data_task::locks(Task_locker* tl)
|
|
{
|
|
tl->add(this, this->final_blocker_);
|
|
}
|
|
|
|
// 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_token*
|
|
Write_symbols_task::is_runnable()
|
|
{
|
|
return NULL;
|
|
}
|
|
|
|
// We need to unlock FINAL_BLOCKER when finished.
|
|
|
|
void
|
|
Write_symbols_task::locks(Task_locker* tl)
|
|
{
|
|
tl->add(this, this->final_blocker_);
|
|
}
|
|
|
|
// Run the task--write out the symbols.
|
|
|
|
void
|
|
Write_symbols_task::run(Workqueue*)
|
|
{
|
|
this->symtab_->write_globals(this->sympool_, this->dynpool_,
|
|
this->layout_->symtab_xindex(),
|
|
this->layout_->dynsym_xindex(), this->of_);
|
|
}
|
|
|
|
// Write_after_input_sections_task methods.
|
|
|
|
// We can only run this task after the input sections have completed.
|
|
|
|
Task_token*
|
|
Write_after_input_sections_task::is_runnable()
|
|
{
|
|
if (this->input_sections_blocker_->is_blocked())
|
|
return this->input_sections_blocker_;
|
|
return NULL;
|
|
}
|
|
|
|
// We need to unlock FINAL_BLOCKER when finished.
|
|
|
|
void
|
|
Write_after_input_sections_task::locks(Task_locker* tl)
|
|
{
|
|
tl->add(this, this->final_blocker_);
|
|
}
|
|
|
|
// Run the task.
|
|
|
|
void
|
|
Write_after_input_sections_task::run(Workqueue*)
|
|
{
|
|
this->layout_->write_sections_after_input_sections(this->of_);
|
|
}
|
|
|
|
// Close_task_runner methods.
|
|
|
|
// Run the task--close the file.
|
|
|
|
void
|
|
Close_task_runner::run(Workqueue*, const Task*)
|
|
{
|
|
// If we need to compute a checksum for the BUILD if, we do so here.
|
|
this->layout_->write_build_id(this->of_);
|
|
|
|
// If we've been asked to create a binary file, we do so here.
|
|
if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF)
|
|
this->layout_->write_binary(this->of_);
|
|
|
|
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>(Sized_relobj<32, false>* object, unsigned int shndx,
|
|
const char* name,
|
|
const elfcpp::Shdr<32, false>& shdr,
|
|
unsigned int, unsigned int, off_t*);
|
|
#endif
|
|
|
|
#ifdef HAVE_TARGET_32_BIG
|
|
template
|
|
Output_section*
|
|
Layout::layout<32, true>(Sized_relobj<32, true>* object, unsigned int shndx,
|
|
const char* name,
|
|
const elfcpp::Shdr<32, true>& shdr,
|
|
unsigned int, unsigned int, off_t*);
|
|
#endif
|
|
|
|
#ifdef HAVE_TARGET_64_LITTLE
|
|
template
|
|
Output_section*
|
|
Layout::layout<64, false>(Sized_relobj<64, false>* object, unsigned int shndx,
|
|
const char* name,
|
|
const elfcpp::Shdr<64, false>& shdr,
|
|
unsigned int, unsigned int, off_t*);
|
|
#endif
|
|
|
|
#ifdef HAVE_TARGET_64_BIG
|
|
template
|
|
Output_section*
|
|
Layout::layout<64, true>(Sized_relobj<64, true>* object, unsigned int shndx,
|
|
const char* name,
|
|
const elfcpp::Shdr<64, true>& shdr,
|
|
unsigned int, unsigned int, off_t*);
|
|
#endif
|
|
|
|
#ifdef HAVE_TARGET_32_LITTLE
|
|
template
|
|
Output_section*
|
|
Layout::layout_reloc<32, false>(Sized_relobj<32, false>* object,
|
|
unsigned int reloc_shndx,
|
|
const elfcpp::Shdr<32, false>& shdr,
|
|
Output_section* data_section,
|
|
Relocatable_relocs* rr);
|
|
#endif
|
|
|
|
#ifdef HAVE_TARGET_32_BIG
|
|
template
|
|
Output_section*
|
|
Layout::layout_reloc<32, true>(Sized_relobj<32, true>* object,
|
|
unsigned int reloc_shndx,
|
|
const elfcpp::Shdr<32, true>& shdr,
|
|
Output_section* data_section,
|
|
Relocatable_relocs* rr);
|
|
#endif
|
|
|
|
#ifdef HAVE_TARGET_64_LITTLE
|
|
template
|
|
Output_section*
|
|
Layout::layout_reloc<64, false>(Sized_relobj<64, false>* object,
|
|
unsigned int reloc_shndx,
|
|
const elfcpp::Shdr<64, false>& shdr,
|
|
Output_section* data_section,
|
|
Relocatable_relocs* rr);
|
|
#endif
|
|
|
|
#ifdef HAVE_TARGET_64_BIG
|
|
template
|
|
Output_section*
|
|
Layout::layout_reloc<64, true>(Sized_relobj<64, true>* object,
|
|
unsigned int reloc_shndx,
|
|
const elfcpp::Shdr<64, true>& shdr,
|
|
Output_section* data_section,
|
|
Relocatable_relocs* rr);
|
|
#endif
|
|
|
|
#ifdef HAVE_TARGET_32_LITTLE
|
|
template
|
|
void
|
|
Layout::layout_group<32, false>(Symbol_table* symtab,
|
|
Sized_relobj<32, false>* object,
|
|
unsigned int,
|
|
const char* group_section_name,
|
|
const char* signature,
|
|
const elfcpp::Shdr<32, false>& shdr,
|
|
elfcpp::Elf_Word flags,
|
|
std::vector<unsigned int>* shndxes);
|
|
#endif
|
|
|
|
#ifdef HAVE_TARGET_32_BIG
|
|
template
|
|
void
|
|
Layout::layout_group<32, true>(Symbol_table* symtab,
|
|
Sized_relobj<32, true>* object,
|
|
unsigned int,
|
|
const char* group_section_name,
|
|
const char* signature,
|
|
const elfcpp::Shdr<32, true>& shdr,
|
|
elfcpp::Elf_Word flags,
|
|
std::vector<unsigned int>* shndxes);
|
|
#endif
|
|
|
|
#ifdef HAVE_TARGET_64_LITTLE
|
|
template
|
|
void
|
|
Layout::layout_group<64, false>(Symbol_table* symtab,
|
|
Sized_relobj<64, false>* object,
|
|
unsigned int,
|
|
const char* group_section_name,
|
|
const char* signature,
|
|
const elfcpp::Shdr<64, false>& shdr,
|
|
elfcpp::Elf_Word flags,
|
|
std::vector<unsigned int>* shndxes);
|
|
#endif
|
|
|
|
#ifdef HAVE_TARGET_64_BIG
|
|
template
|
|
void
|
|
Layout::layout_group<64, true>(Symbol_table* symtab,
|
|
Sized_relobj<64, true>* object,
|
|
unsigned int,
|
|
const char* group_section_name,
|
|
const char* signature,
|
|
const elfcpp::Shdr<64, true>& shdr,
|
|
elfcpp::Elf_Word flags,
|
|
std::vector<unsigned int>* shndxes);
|
|
#endif
|
|
|
|
#ifdef HAVE_TARGET_32_LITTLE
|
|
template
|
|
Output_section*
|
|
Layout::layout_eh_frame<32, false>(Sized_relobj<32, false>* object,
|
|
const unsigned char* symbols,
|
|
off_t symbols_size,
|
|
const unsigned char* symbol_names,
|
|
off_t symbol_names_size,
|
|
unsigned int shndx,
|
|
const elfcpp::Shdr<32, false>& shdr,
|
|
unsigned int reloc_shndx,
|
|
unsigned int reloc_type,
|
|
off_t* off);
|
|
#endif
|
|
|
|
#ifdef HAVE_TARGET_32_BIG
|
|
template
|
|
Output_section*
|
|
Layout::layout_eh_frame<32, true>(Sized_relobj<32, true>* object,
|
|
const unsigned char* symbols,
|
|
off_t symbols_size,
|
|
const unsigned char* symbol_names,
|
|
off_t symbol_names_size,
|
|
unsigned int shndx,
|
|
const elfcpp::Shdr<32, true>& shdr,
|
|
unsigned int reloc_shndx,
|
|
unsigned int reloc_type,
|
|
off_t* off);
|
|
#endif
|
|
|
|
#ifdef HAVE_TARGET_64_LITTLE
|
|
template
|
|
Output_section*
|
|
Layout::layout_eh_frame<64, false>(Sized_relobj<64, false>* object,
|
|
const unsigned char* symbols,
|
|
off_t symbols_size,
|
|
const unsigned char* symbol_names,
|
|
off_t symbol_names_size,
|
|
unsigned int shndx,
|
|
const elfcpp::Shdr<64, false>& shdr,
|
|
unsigned int reloc_shndx,
|
|
unsigned int reloc_type,
|
|
off_t* off);
|
|
#endif
|
|
|
|
#ifdef HAVE_TARGET_64_BIG
|
|
template
|
|
Output_section*
|
|
Layout::layout_eh_frame<64, true>(Sized_relobj<64, true>* object,
|
|
const unsigned char* symbols,
|
|
off_t symbols_size,
|
|
const unsigned char* symbol_names,
|
|
off_t symbol_names_size,
|
|
unsigned int shndx,
|
|
const elfcpp::Shdr<64, true>& shdr,
|
|
unsigned int reloc_shndx,
|
|
unsigned int reloc_type,
|
|
off_t* off);
|
|
#endif
|
|
|
|
} // End namespace gold.
|