diff options
Diffstat (limited to 'gold/layout.cc')
| -rw-r--r-- | gold/layout.cc | 150 |
1 files changed, 126 insertions, 24 deletions
diff --git a/gold/layout.cc b/gold/layout.cc index 13f57cb82f..b593acdb0b 100644 --- a/gold/layout.cc +++ b/gold/layout.cc @@ -236,6 +236,54 @@ Free_list::print_stats() program_name, Free_list::num_allocate_visits); } +// A Hash_task computes the MD5 checksum of an array of char. +// It has a blocker on either side (i.e., the task cannot run until +// the first is unblocked, and it unblocks the second after running). + +class Hash_task : public Task +{ + public: + Hash_task(const unsigned char* src, + size_t size, + unsigned char* dst, + Task_token* build_id_blocker, + Task_token* final_blocker) + : src_(src), size_(size), dst_(dst), build_id_blocker_(build_id_blocker), + final_blocker_(final_blocker) + { } + + void + run(Workqueue*) + { md5_buffer(reinterpret_cast<const char*>(src_), size_, dst_); } + + Task_token* + is_runnable(); + + // Unblock FINAL_BLOCKER_ when done. + void + locks(Task_locker* tl) + { tl->add(this, this->final_blocker_); } + + std::string + get_name() const + { return "Hash_task"; } + + private: + const unsigned char* const src_; + const size_t size_; + unsigned char* const dst_; + Task_token* const build_id_blocker_; + Task_token* const final_blocker_; +}; + +Task_token* +Hash_task::is_runnable() +{ + if (this->build_id_blocker_->is_blocked()) + return this->build_id_blocker_; + return NULL; +} + // Layout::Relaxation_debug_check methods. // Check that sections and special data are in reset states. @@ -398,6 +446,9 @@ Layout::Layout(int number_of_input_files, Script_options* script_options) eh_frame_hdr_section_(NULL), gdb_index_data_(NULL), build_id_note_(NULL), + array_of_hashes_(NULL), + size_of_array_of_hashes_(0), + input_view_(NULL), debug_abbrev_(NULL), debug_info_(NULL), group_signatures_(), @@ -2924,7 +2975,7 @@ Layout::create_build_id() std::string desc; if (strcmp(style, "md5") == 0) descsz = 128 / 8; - else if (strcmp(style, "sha1") == 0) + else if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0)) descsz = 160 / 8; else if (strcmp(style, "uuid") == 0) { @@ -5212,9 +5263,53 @@ Layout::write_sections_after_input_sections(Output_file* 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. +// Build IDs can be computed as a "flat" sha1 or md5 of a string of bytes, +// or as a "tree" where each chunk of the string is hashed and then those +// hashes are put into a (much smaller) string which is hashed with sha1. +// We compute a checksum over the entire file because that is simplest. + +Task_token* +Layout::queue_build_id_tasks(Workqueue* workqueue, Task_token* build_id_blocker, + Output_file* of) +{ + const size_t filesize = (this->output_file_size() <= 0 ? 0 + : static_cast<size_t>(this->output_file_size())); + if (this->build_id_note_ != NULL + && strcmp(parameters->options().build_id(), "tree") == 0 + && parameters->options().build_id_chunk_size_for_treehash() > 0 + && filesize > 0 + && (filesize >= + parameters->options().build_id_min_file_size_for_treehash())) + { + static const size_t MD5_OUTPUT_SIZE_IN_BYTES = 16; + const size_t chunk_size = + parameters->options().build_id_chunk_size_for_treehash(); + const size_t num_hashes = ((filesize - 1) / chunk_size) + 1; + Task_token* post_hash_tasks_blocker = new Task_token(true); + post_hash_tasks_blocker->add_blockers(num_hashes); + this->size_of_array_of_hashes_ = num_hashes * MD5_OUTPUT_SIZE_IN_BYTES; + const unsigned char* src = of->get_input_view(0, filesize); + this->input_view_ = src; + unsigned char *dst = new unsigned char[this->size_of_array_of_hashes_]; + this->array_of_hashes_ = dst; + for (size_t i = 0, src_offset = 0; i < num_hashes; + i++, dst += MD5_OUTPUT_SIZE_IN_BYTES, src_offset += chunk_size) + { + size_t size = std::min(chunk_size, filesize - src_offset); + workqueue->queue(new Hash_task(src + src_offset, + size, + dst, + build_id_blocker, + post_hash_tasks_blocker)); + } + return post_hash_tasks_blocker; + } + return build_id_blocker; +} + +// If a tree-style build ID was requested, the parallel part of that computation +// is already done, and the final hash-of-hashes is computed here. For other +// types of build IDs, all the work is done here. void Layout::write_build_id(Output_file* of) const @@ -5222,34 +5317,39 @@ 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()); + this->build_id_note_->data_size()); - const char* style = parameters->options().build_id(); - if (strcmp(style, "sha1") == 0) + if (this->array_of_hashes_ == NULL) { - sha1_ctx ctx; - sha1_init_ctx(&ctx); - sha1_process_bytes(iv, this->output_file_size_, &ctx); - sha1_finish_ctx(&ctx, ov); + const size_t output_file_size = this->output_file_size(); + const unsigned char* iv = of->get_input_view(0, output_file_size); + const char* style = parameters->options().build_id(); + + // If we get here with style == "tree" then the output must be + // too small for chunking, and we use SHA-1 in that case. + if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0)) + sha1_buffer(reinterpret_cast<const char*>(iv), output_file_size, ov); + else if (strcmp(style, "md5") == 0) + md5_buffer(reinterpret_cast<const char*>(iv), output_file_size, ov); + else + gold_unreachable(); + + of->free_input_view(0, output_file_size, iv); } - else if (strcmp(style, "md5") == 0) + else { - md5_ctx ctx; - md5_init_ctx(&ctx); - md5_process_bytes(iv, this->output_file_size_, &ctx); - md5_finish_ctx(&ctx, ov); + // Non-overlapping substrings of the output file have been hashed. + // Compute SHA-1 hash of the hashes. + sha1_buffer(reinterpret_cast<const char*>(this->array_of_hashes_), + this->size_of_array_of_hashes_, ov); + delete[] this->array_of_hashes_; + of->free_input_view(0, this->output_file_size(), this->input_view_); } - 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 @@ -5439,12 +5539,14 @@ Write_after_input_sections_task::run(Workqueue*) // Close_task_runner methods. -// Run the task--close the file. +// Finish up the build ID computation, if necessary, and write a binary file, +// if necessary. Then close the output file. void Close_task_runner::run(Workqueue*, const Task*) { - // If we need to compute a checksum for the BUILD if, we do so here. + // At this point the multi-threaded part of the build ID computation, + // if any, is done. See queue_build_id_tasks(). this->layout_->write_build_id(this->of_); // If we've been asked to create a binary file, we do so here. |