| // inremental.cc -- incremental linking support for gold |
| |
| // Copyright 2009 Free Software Foundation, Inc. |
| // Written by Mikolaj Zalewski <mikolajz@google.com>. |
| |
| // This file is part of gold. |
| |
| // This program is free software; you can redistribute it and/or modify |
| // it under the terms of the GNU General Public License as published by |
| // the Free Software Foundation; either version 3 of the License, or |
| // (at your option) any later version. |
| |
| // This program is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // You should have received a copy of the GNU General Public License |
| // along with this program; if not, write to the Free Software |
| // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
| // MA 02110-1301, USA. |
| |
| #include "gold.h" |
| |
| #include <cstdarg> |
| |
| #include "elfcpp.h" |
| #include "output.h" |
| #include "incremental.h" |
| #include "archive.h" |
| #include "output.h" |
| #include "target-select.h" |
| |
| namespace gold { |
| |
| // Version information. Will change frequently during the development, later |
| // we could think about backward (and forward?) compatibility. |
| const unsigned int INCREMENTAL_LINK_VERSION = 1; |
| |
| // Inform the user why we don't do an incremental link. Not called in |
| // the obvious case of missing output file. TODO: Is this helpful? |
| |
| void |
| vexplain_no_incremental(const char* format, va_list args) |
| { |
| char* buf = NULL; |
| if (vasprintf(&buf, format, args) < 0) |
| gold_nomem(); |
| gold_info(_("the link might take longer: " |
| "cannot perform incremental link: %s"), buf); |
| free(buf); |
| } |
| |
| void |
| explain_no_incremental(const char* format, ...) |
| { |
| va_list args; |
| va_start(args, format); |
| vexplain_no_incremental(format, args); |
| va_end(args); |
| } |
| |
| // Report an error. |
| |
| void |
| Incremental_binary::error(const char* format, ...) const |
| { |
| va_list args; |
| va_start(args, format); |
| // Current code only checks if the file can be used for incremental linking, |
| // so errors shouldn't fail the build, but only result in a fallback to a |
| // full build. |
| // TODO: when we implement incremental editing of the file, we may need a |
| // flag that will cause errors to be treated seriously. |
| vexplain_no_incremental(format, args); |
| va_end(args); |
| } |
| |
| template<int size, bool big_endian> |
| bool |
| Sized_incremental_binary<size, big_endian>::do_find_incremental_inputs_section( |
| Location* location, |
| unsigned int* strtab_shndx) |
| { |
| unsigned int shndx = this->elf_file_.find_section_by_type( |
| elfcpp::SHT_GNU_INCREMENTAL_INPUTS); |
| if (shndx == elfcpp::SHN_UNDEF) // Not found. |
| return false; |
| *strtab_shndx = this->elf_file_.section_link(shndx); |
| *location = this->elf_file_.section_contents(shndx); |
| return true; |
| } |
| |
| template<int size, bool big_endian> |
| bool |
| Sized_incremental_binary<size, big_endian>::do_check_inputs( |
| Incremental_inputs* incremental_inputs) |
| { |
| const int entry_size = |
| Incremental_inputs_entry_write<size, big_endian>::data_size; |
| const int header_size = |
| Incremental_inputs_header_write<size, big_endian>::data_size; |
| |
| unsigned int strtab_shndx; |
| Location location; |
| |
| if (!do_find_incremental_inputs_section(&location, &strtab_shndx)) |
| { |
| explain_no_incremental(_("no incremental data from previous build")); |
| return false; |
| } |
| if (location.data_size < header_size |
| || strtab_shndx >= this->elf_file_.shnum() |
| || this->elf_file_.section_type(strtab_shndx) != elfcpp::SHT_STRTAB) |
| { |
| explain_no_incremental(_("invalid incremental build data")); |
| return false; |
| } |
| |
| Location strtab_location(this->elf_file_.section_contents(strtab_shndx)); |
| View data_view(view(location)); |
| View strtab_view(view(strtab_location)); |
| elfcpp::Elf_strtab strtab(strtab_view.data(), strtab_location.data_size); |
| Incremental_inputs_header<size, big_endian> header(data_view.data()); |
| |
| if (header.get_version() != INCREMENTAL_LINK_VERSION) |
| { |
| explain_no_incremental(_("different version of incremental build data")); |
| return false; |
| } |
| |
| const char* command_line; |
| // We divide instead of multiplying to make sure there is no integer |
| // overflow. |
| size_t max_input_entries = (location.data_size - header_size) / entry_size; |
| if (header.get_input_file_count() > max_input_entries |
| || !strtab.get_c_string(header.get_command_line_offset(), &command_line)) |
| { |
| explain_no_incremental(_("invalid incremental build data")); |
| return false; |
| } |
| |
| if (incremental_inputs->command_line() != command_line) |
| { |
| explain_no_incremental(_("command line changed")); |
| return false; |
| } |
| |
| // TODO: compare incremental_inputs->inputs() with entries in data_view. |
| return true; |
| } |
| |
| namespace |
| { |
| |
| // Create a Sized_incremental_binary object of the specified size and |
| // endianness. Fails if the target architecture is not supported. |
| |
| template<int size, bool big_endian> |
| Incremental_binary* |
| make_sized_incremental_binary(Output_file* file, |
| const elfcpp::Ehdr<size, big_endian>& ehdr) |
| { |
| Target* target = select_target(ehdr.get_e_machine(), size, big_endian, |
| ehdr.get_e_ident()[elfcpp::EI_OSABI], |
| ehdr.get_e_ident()[elfcpp::EI_ABIVERSION]); |
| if (target == NULL) |
| { |
| explain_no_incremental(_("unsupported ELF machine number %d"), |
| ehdr.get_e_machine()); |
| return NULL; |
| } |
| |
| if (!parameters->target_valid()) |
| set_parameters_target(target); |
| else if (target != ¶meters->target()) |
| gold_error(_("%s: incompatible target"), file->filename()); |
| |
| return new Sized_incremental_binary<size, big_endian>(file, ehdr, target); |
| } |
| |
| } // End of anonymous namespace. |
| |
| // Create an Incremental_binary object for FILE. Returns NULL is this is not |
| // possible, e.g. FILE is not an ELF file or has an unsupported target. FILE |
| // should be opened. |
| |
| Incremental_binary* |
| open_incremental_binary(Output_file* file) |
| { |
| off_t filesize = file->filesize(); |
| int want = elfcpp::Elf_recognizer::max_header_size; |
| if (filesize < want) |
| want = filesize; |
| |
| const unsigned char* p = file->get_input_view(0, want); |
| if (!elfcpp::Elf_recognizer::is_elf_file(p, want)) |
| { |
| explain_no_incremental(_("output is not an ELF file.")); |
| return NULL; |
| } |
| |
| int size = 0; |
| bool big_endian = false; |
| std::string error; |
| if (!elfcpp::Elf_recognizer::is_valid_header(p, want, &size, &big_endian, |
| &error)) |
| { |
| explain_no_incremental(error.c_str()); |
| return NULL; |
| } |
| |
| Incremental_binary* result = NULL; |
| if (size == 32) |
| { |
| if (big_endian) |
| { |
| #ifdef HAVE_TARGET_32_BIG |
| result = make_sized_incremental_binary<32, true>( |
| file, elfcpp::Ehdr<32, true>(p)); |
| #else |
| explain_no_incremental(_("unsupported file: 32-bit, big-endian")); |
| #endif |
| } |
| else |
| { |
| #ifdef HAVE_TARGET_32_LITTLE |
| result = make_sized_incremental_binary<32, false>( |
| file, elfcpp::Ehdr<32, false>(p)); |
| #else |
| explain_no_incremental(_("unsupported file: 32-bit, little-endian")); |
| #endif |
| } |
| } |
| else if (size == 64) |
| { |
| if (big_endian) |
| { |
| #ifdef HAVE_TARGET_64_BIG |
| result = make_sized_incremental_binary<64, true>( |
| file, elfcpp::Ehdr<64, true>(p)); |
| #else |
| explain_no_incremental(_("unsupported file: 64-bit, big-endian")); |
| #endif |
| } |
| else |
| { |
| #ifdef HAVE_TARGET_64_LITTLE |
| result = make_sized_incremental_binary<64, false>( |
| file, elfcpp::Ehdr<64, false>(p)); |
| #else |
| explain_no_incremental(_("unsupported file: 64-bit, little-endian")); |
| #endif |
| } |
| } |
| else |
| gold_unreachable(); |
| |
| return result; |
| } |
| |
| // Analyzes the output file to check if incremental linking is possible and |
| // (to be done) what files need to be relinked. |
| |
| bool |
| Incremental_checker::can_incrementally_link_output_file() |
| { |
| Output_file output(this->output_name_); |
| if (!output.open_for_modification()) |
| return false; |
| Incremental_binary* binary = open_incremental_binary(&output); |
| if (binary == NULL) |
| return false; |
| return binary->check_inputs(this->incremental_inputs_); |
| } |
| |
| // Add the command line to the string table, setting |
| // command_line_key_. In incremental builds, the command line is |
| // stored in .gnu_incremental_inputs so that the next linker run can |
| // check if the command line options didn't change. |
| |
| void |
| Incremental_inputs::report_command_line(int argc, const char* const* argv) |
| { |
| // Always store 'gold' as argv[0] to avoid a full relink if the user used a |
| // different path to the linker. |
| std::string args("gold"); |
| // Copied from collect_argv in main.cc. |
| for (int i = 1; i < argc; ++i) |
| { |
| // Adding/removing these options should result in a full relink. |
| if (strcmp(argv[i], "--incremental-changed") == 0 |
| || strcmp(argv[i], "--incremental-unchanged") == 0 |
| || strcmp(argv[i], "--incremental-unknown") == 0) |
| continue; |
| |
| args.append(" '"); |
| // Now append argv[i], but with all single-quotes escaped |
| const char* argpos = argv[i]; |
| while (1) |
| { |
| const int len = strcspn(argpos, "'"); |
| args.append(argpos, len); |
| if (argpos[len] == '\0') |
| break; |
| args.append("'\"'\"'"); |
| argpos += len + 1; |
| } |
| args.append("'"); |
| } |
| |
| this->command_line_ = args; |
| this->strtab_->add(this->command_line_.c_str(), false, |
| &this->command_line_key_); |
| } |
| |
| // Record that the input argument INPUT is an achive ARCHIVE. This is |
| // called by Read_symbols after finding out the type of the file. |
| |
| void |
| Incremental_inputs::report_archive(const Input_argument* input, |
| Archive* archive) |
| { |
| Hold_lock hl(*this->lock_); |
| |
| Input_info info; |
| info.type = INCREMENTAL_INPUT_ARCHIVE; |
| info.archive = archive; |
| info.mtime = archive->file().get_mtime(); |
| this->inputs_map_.insert(std::make_pair(input, info)); |
| } |
| |
| // Record that the input argument INPUT is an object OBJ. This is |
| // called by Read_symbols after finding out the type of the file. |
| |
| void |
| Incremental_inputs::report_object(const Input_argument* input, |
| Object* obj) |
| { |
| Hold_lock hl(*this->lock_); |
| |
| Input_info info; |
| info.type = (obj->is_dynamic() |
| ? INCREMENTAL_INPUT_SHARED_LIBRARY |
| : INCREMENTAL_INPUT_OBJECT); |
| info.object = obj; |
| info.mtime = obj->input_file()->file().get_mtime(); |
| this->inputs_map_.insert(std::make_pair(input, info)); |
| } |
| |
| // Record that the input argument INPUT is an script SCRIPT. This is |
| // called by read_script after parsing the script and reading the list |
| // of inputs added by this script. |
| |
| void |
| Incremental_inputs::report_script(const Input_argument* input, |
| Timespec mtime, |
| Script_info* script) |
| { |
| Hold_lock hl(*this->lock_); |
| |
| Input_info info; |
| info.type = INCREMENTAL_INPUT_SCRIPT; |
| info.script = script; |
| info.mtime = mtime; |
| this->inputs_map_.insert(std::make_pair(input, info)); |
| } |
| |
| // Compute indexes in the order in which the inputs should appear in |
| // .gnu_incremental_inputs. This needs to be done after all the |
| // scripts are parsed. The function is first called for the command |
| // line inputs arguments and may call itself recursively for e.g. a |
| // list of elements of a group or a list of inputs added by a script. |
| // The [BEGIN; END) interval to analyze and *INDEX is the current |
| // value of the index (that will be updated). |
| |
| void |
| Incremental_inputs::finalize_inputs( |
| Input_argument_list::const_iterator begin, |
| Input_argument_list::const_iterator end, |
| unsigned int* index) |
| { |
| for (Input_argument_list::const_iterator p = begin; p != end; ++p) |
| { |
| if (p->is_group()) |
| { |
| finalize_inputs(p->group()->begin(), p->group()->end(), index); |
| continue; |
| } |
| |
| Inputs_info_map::iterator it = this->inputs_map_.find(&(*p)); |
| // TODO: turn it into an assert when the code will be more stable. |
| if (it == this->inputs_map_.end()) |
| { |
| gold_error("internal error: %s: incremental build info not provided", |
| (p->is_file() ? p->file().name() : "[group]")); |
| continue; |
| } |
| Input_info* info = &it->second; |
| info->index = *index; |
| (*index)++; |
| this->strtab_->add(p->file().name(), false, &info->filename_key); |
| if (info->type == INCREMENTAL_INPUT_SCRIPT) |
| { |
| finalize_inputs(info->script->inputs()->begin(), |
| info->script->inputs()->end(), |
| index); |
| } |
| } |
| } |
| |
| // Finalize the incremental link information. Called from |
| // Layout::finalize. |
| |
| void |
| Incremental_inputs::finalize() |
| { |
| unsigned int index = 0; |
| finalize_inputs(this->inputs_->begin(), this->inputs_->end(), &index); |
| |
| // Sanity check. |
| for (Inputs_info_map::const_iterator p = this->inputs_map_.begin(); |
| p != this->inputs_map_.end(); |
| ++p) |
| { |
| gold_assert(p->second.filename_key != 0); |
| } |
| |
| this->strtab_->set_string_offsets(); |
| } |
| |
| // Create the content of the .gnu_incremental_inputs section. |
| |
| Output_section_data* |
| Incremental_inputs::create_incremental_inputs_section_data() |
| { |
| switch (parameters->size_and_endianness()) |
| { |
| #ifdef HAVE_TARGET_32_LITTLE |
| case Parameters::TARGET_32_LITTLE: |
| return this->sized_create_inputs_section_data<32, false>(); |
| #endif |
| #ifdef HAVE_TARGET_32_BIG |
| case Parameters::TARGET_32_BIG: |
| return this->sized_create_inputs_section_data<32, true>(); |
| #endif |
| #ifdef HAVE_TARGET_64_LITTLE |
| case Parameters::TARGET_64_LITTLE: |
| return this->sized_create_inputs_section_data<64, false>(); |
| #endif |
| #ifdef HAVE_TARGET_64_BIG |
| case Parameters::TARGET_64_BIG: |
| return this->sized_create_inputs_section_data<64, true>(); |
| #endif |
| default: |
| gold_unreachable(); |
| } |
| } |
| |
| // Sized creation of .gnu_incremental_inputs section. |
| |
| template<int size, bool big_endian> |
| Output_section_data* |
| Incremental_inputs::sized_create_inputs_section_data() |
| { |
| const int entry_size = |
| Incremental_inputs_entry_write<size, big_endian>::data_size; |
| const int header_size = |
| Incremental_inputs_header_write<size, big_endian>::data_size; |
| |
| unsigned int sz = header_size + entry_size * this->inputs_map_.size(); |
| unsigned char* buffer = new unsigned char[sz]; |
| unsigned char* inputs_base = buffer + header_size; |
| |
| Incremental_inputs_header_write<size, big_endian> header_writer(buffer); |
| gold_assert(this->command_line_key_ > 0); |
| int cmd_offset = this->strtab_->get_offset_from_key(this->command_line_key_); |
| |
| header_writer.put_version(INCREMENTAL_LINK_VERSION); |
| header_writer.put_input_file_count(this->inputs_map_.size()); |
| header_writer.put_command_line_offset(cmd_offset); |
| header_writer.put_reserved(0); |
| |
| for (Inputs_info_map::const_iterator it = this->inputs_map_.begin(); |
| it != this->inputs_map_.end(); |
| ++it) |
| { |
| gold_assert(it->second.index < this->inputs_map_.size()); |
| |
| unsigned char* entry_buffer = |
| inputs_base + it->second.index * entry_size; |
| Incremental_inputs_entry_write<size, big_endian> entry(entry_buffer); |
| int filename_offset = |
| this->strtab_->get_offset_from_key(it->second.filename_key); |
| entry.put_filename_offset(filename_offset); |
| switch (it->second.type) |
| { |
| case INCREMENTAL_INPUT_SCRIPT: |
| entry.put_data_offset(0); |
| break; |
| case INCREMENTAL_INPUT_ARCHIVE: |
| case INCREMENTAL_INPUT_OBJECT: |
| case INCREMENTAL_INPUT_SHARED_LIBRARY: |
| // TODO: add per input data. Currently we store |
| // an out-of-bounds offset for future version of gold to reject |
| // such an incremental_inputs section. |
| entry.put_data_offset(0xffffffff); |
| break; |
| default: |
| gold_unreachable(); |
| } |
| entry.put_timestamp_sec(it->second.mtime.seconds); |
| entry.put_timestamp_nsec(it->second.mtime.nanoseconds); |
| entry.put_input_type(it->second.type); |
| entry.put_reserved(0); |
| } |
| |
| return new Output_data_const_buffer(buffer, sz, 8, |
| "** incremental link inputs list"); |
| } |
| |
| // Instantiate the templates we need. |
| |
| #ifdef HAVE_TARGET_32_LITTLE |
| template |
| class Sized_incremental_binary<32, false>; |
| #endif |
| |
| #ifdef HAVE_TARGET_32_BIG |
| template |
| class Sized_incremental_binary<32, true>; |
| #endif |
| |
| #ifdef HAVE_TARGET_64_LITTLE |
| template |
| class Sized_incremental_binary<64, false>; |
| #endif |
| |
| #ifdef HAVE_TARGET_64_BIG |
| template |
| class Sized_incremental_binary<64, true>; |
| #endif |
| |
| } // End namespace gold. |