| 1 | // gold.cc -- main linker functions |
| 2 | |
| 3 | // Copyright (C) 2006-2020 Free Software Foundation, Inc. |
| 4 | // Written by Ian Lance Taylor <iant@google.com>. |
| 5 | |
| 6 | // This file is part of gold. |
| 7 | |
| 8 | // This program is free software; you can redistribute it and/or modify |
| 9 | // it under the terms of the GNU General Public License as published by |
| 10 | // the Free Software Foundation; either version 3 of the License, or |
| 11 | // (at your option) any later version. |
| 12 | |
| 13 | // This program is distributed in the hope that it will be useful, |
| 14 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | // GNU General Public License for more details. |
| 17 | |
| 18 | // You should have received a copy of the GNU General Public License |
| 19 | // along with this program; if not, write to the Free Software |
| 20 | // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
| 21 | // MA 02110-1301, USA. |
| 22 | |
| 23 | #include "gold.h" |
| 24 | |
| 25 | #include <cstdlib> |
| 26 | #include <cstdio> |
| 27 | #include <cstring> |
| 28 | #include <unistd.h> |
| 29 | #include <algorithm> |
| 30 | #include "libiberty.h" |
| 31 | |
| 32 | #include "options.h" |
| 33 | #include "target-select.h" |
| 34 | #include "debug.h" |
| 35 | #include "workqueue.h" |
| 36 | #include "dirsearch.h" |
| 37 | #include "readsyms.h" |
| 38 | #include "symtab.h" |
| 39 | #include "common.h" |
| 40 | #include "object.h" |
| 41 | #include "layout.h" |
| 42 | #include "reloc.h" |
| 43 | #include "defstd.h" |
| 44 | #include "plugin.h" |
| 45 | #include "gc.h" |
| 46 | #include "icf.h" |
| 47 | #include "incremental.h" |
| 48 | #include "timer.h" |
| 49 | |
| 50 | namespace gold |
| 51 | { |
| 52 | |
| 53 | class Object; |
| 54 | |
| 55 | const char* program_name; |
| 56 | |
| 57 | static Task* |
| 58 | process_incremental_input(Incremental_binary*, unsigned int, Input_objects*, |
| 59 | Symbol_table*, Layout*, Dirsearch*, Mapfile*, |
| 60 | Task_token*, Task_token*); |
| 61 | |
| 62 | void |
| 63 | gold_exit(Exit_status status) |
| 64 | { |
| 65 | if (parameters != NULL |
| 66 | && parameters->options_valid() |
| 67 | && parameters->options().has_plugins()) |
| 68 | parameters->options().plugins()->cleanup(); |
| 69 | if (status != GOLD_OK && parameters != NULL && parameters->options_valid()) |
| 70 | unlink_if_ordinary(parameters->options().output_file_name()); |
| 71 | exit(status); |
| 72 | } |
| 73 | |
| 74 | void |
| 75 | gold_nomem() |
| 76 | { |
| 77 | // We are out of memory, so try hard to print a reasonable message. |
| 78 | // Note that we don't try to translate this message, since the |
| 79 | // translation process itself will require memory. |
| 80 | |
| 81 | // LEN only exists to avoid a pointless warning when write is |
| 82 | // declared with warn_use_result, as when compiling with |
| 83 | // -D_USE_FORTIFY on GNU/Linux. Casting to void does not appear to |
| 84 | // work, at least not with gcc 4.3.0. |
| 85 | |
| 86 | ssize_t len = write(2, program_name, strlen(program_name)); |
| 87 | if (len >= 0) |
| 88 | { |
| 89 | const char* const s = ": out of memory\n"; |
| 90 | len = write(2, s, strlen(s)); |
| 91 | } |
| 92 | gold_exit(GOLD_ERR); |
| 93 | } |
| 94 | |
| 95 | // Handle an unreachable case. |
| 96 | |
| 97 | void |
| 98 | do_gold_unreachable(const char* filename, int lineno, const char* function) |
| 99 | { |
| 100 | fprintf(stderr, _("%s: internal error in %s, at %s:%d\n"), |
| 101 | program_name, function, filename, lineno); |
| 102 | gold_exit(GOLD_ERR); |
| 103 | } |
| 104 | |
| 105 | // This class arranges to run the functions done in the middle of the |
| 106 | // link. It is just a closure. |
| 107 | |
| 108 | class Middle_runner : public Task_function_runner |
| 109 | { |
| 110 | public: |
| 111 | Middle_runner(const General_options& options, |
| 112 | const Input_objects* input_objects, |
| 113 | Symbol_table* symtab, |
| 114 | Layout* layout, Mapfile* mapfile) |
| 115 | : options_(options), input_objects_(input_objects), symtab_(symtab), |
| 116 | layout_(layout), mapfile_(mapfile) |
| 117 | { } |
| 118 | |
| 119 | void |
| 120 | run(Workqueue*, const Task*); |
| 121 | |
| 122 | private: |
| 123 | const General_options& options_; |
| 124 | const Input_objects* input_objects_; |
| 125 | Symbol_table* symtab_; |
| 126 | Layout* layout_; |
| 127 | Mapfile* mapfile_; |
| 128 | }; |
| 129 | |
| 130 | void |
| 131 | Middle_runner::run(Workqueue* workqueue, const Task* task) |
| 132 | { |
| 133 | queue_middle_tasks(this->options_, task, this->input_objects_, this->symtab_, |
| 134 | this->layout_, workqueue, this->mapfile_); |
| 135 | } |
| 136 | |
| 137 | // This class arranges the tasks to process the relocs for garbage collection. |
| 138 | |
| 139 | class Gc_runner : public Task_function_runner |
| 140 | { |
| 141 | public: |
| 142 | Gc_runner(const General_options& options, |
| 143 | const Input_objects* input_objects, |
| 144 | Symbol_table* symtab, |
| 145 | Layout* layout, Mapfile* mapfile) |
| 146 | : options_(options), input_objects_(input_objects), symtab_(symtab), |
| 147 | layout_(layout), mapfile_(mapfile) |
| 148 | { } |
| 149 | |
| 150 | void |
| 151 | run(Workqueue*, const Task*); |
| 152 | |
| 153 | private: |
| 154 | const General_options& options_; |
| 155 | const Input_objects* input_objects_; |
| 156 | Symbol_table* symtab_; |
| 157 | Layout* layout_; |
| 158 | Mapfile* mapfile_; |
| 159 | }; |
| 160 | |
| 161 | void |
| 162 | Gc_runner::run(Workqueue* workqueue, const Task* task) |
| 163 | { |
| 164 | queue_middle_gc_tasks(this->options_, task, this->input_objects_, |
| 165 | this->symtab_, this->layout_, workqueue, |
| 166 | this->mapfile_); |
| 167 | } |
| 168 | |
| 169 | // Queue up the initial set of tasks for this link job. |
| 170 | |
| 171 | void |
| 172 | queue_initial_tasks(const General_options& options, |
| 173 | Dirsearch& search_path, |
| 174 | const Command_line& cmdline, |
| 175 | Workqueue* workqueue, Input_objects* input_objects, |
| 176 | Symbol_table* symtab, Layout* layout, Mapfile* mapfile) |
| 177 | { |
| 178 | if (cmdline.number_of_input_files() == 0) |
| 179 | { |
| 180 | bool is_ok = false; |
| 181 | if (options.printed_version()) |
| 182 | is_ok = true; |
| 183 | if (options.print_output_format()) |
| 184 | { |
| 185 | print_output_format(); |
| 186 | is_ok = true; |
| 187 | } |
| 188 | if (is_ok) |
| 189 | gold_exit(GOLD_OK); |
| 190 | gold_fatal(_("no input files")); |
| 191 | } |
| 192 | |
| 193 | int thread_count = options.thread_count_initial(); |
| 194 | if (thread_count == 0) |
| 195 | thread_count = cmdline.number_of_input_files(); |
| 196 | workqueue->set_thread_count(thread_count); |
| 197 | |
| 198 | // For incremental links, the base output file. |
| 199 | Incremental_binary* ibase = NULL; |
| 200 | |
| 201 | if (parameters->incremental_update()) |
| 202 | { |
| 203 | Output_file* of = new Output_file(options.output_file_name()); |
| 204 | if (of->open_base_file(options.incremental_base(), true)) |
| 205 | { |
| 206 | ibase = open_incremental_binary(of); |
| 207 | if (ibase != NULL |
| 208 | && ibase->check_inputs(cmdline, layout->incremental_inputs())) |
| 209 | ibase->init_layout(layout); |
| 210 | else |
| 211 | { |
| 212 | delete ibase; |
| 213 | ibase = NULL; |
| 214 | of->close(); |
| 215 | } |
| 216 | } |
| 217 | if (ibase == NULL) |
| 218 | { |
| 219 | if (set_parameters_incremental_full()) |
| 220 | gold_info(_("linking with --incremental-full")); |
| 221 | else |
| 222 | gold_fallback(_("restart link with --incremental-full")); |
| 223 | } |
| 224 | } |
| 225 | |
| 226 | // Read the input files. We have to add the symbols to the symbol |
| 227 | // table in order. We do this by creating a separate blocker for |
| 228 | // each input file. We associate the blocker with the following |
| 229 | // input file, to give us a convenient place to delete it. |
| 230 | Task_token* this_blocker = NULL; |
| 231 | if (ibase == NULL) |
| 232 | { |
| 233 | // Normal link. Queue a Read_symbols task for each input file |
| 234 | // on the command line. |
| 235 | for (Command_line::const_iterator p = cmdline.begin(); |
| 236 | p != cmdline.end(); |
| 237 | ++p) |
| 238 | { |
| 239 | Task_token* next_blocker = new Task_token(true); |
| 240 | next_blocker->add_blocker(); |
| 241 | workqueue->queue(new Read_symbols(input_objects, symtab, layout, |
| 242 | &search_path, 0, mapfile, &*p, NULL, |
| 243 | NULL, this_blocker, next_blocker)); |
| 244 | this_blocker = next_blocker; |
| 245 | } |
| 246 | } |
| 247 | else |
| 248 | { |
| 249 | // Incremental update link. Process the list of input files |
| 250 | // stored in the base file, and queue a task for each file: |
| 251 | // a Read_symbols task for a changed file, and an Add_symbols task |
| 252 | // for an unchanged file. We need to mark all the space used by |
| 253 | // unchanged files before we can start any tasks running. |
| 254 | unsigned int input_file_count = ibase->input_file_count(); |
| 255 | std::vector<Task*> tasks; |
| 256 | tasks.reserve(input_file_count); |
| 257 | for (unsigned int i = 0; i < input_file_count; ++i) |
| 258 | { |
| 259 | Task_token* next_blocker = new Task_token(true); |
| 260 | next_blocker->add_blocker(); |
| 261 | Task* t = process_incremental_input(ibase, i, input_objects, symtab, |
| 262 | layout, &search_path, mapfile, |
| 263 | this_blocker, next_blocker); |
| 264 | tasks.push_back(t); |
| 265 | this_blocker = next_blocker; |
| 266 | } |
| 267 | // Now we can queue the tasks. |
| 268 | for (unsigned int i = 0; i < tasks.size(); i++) |
| 269 | workqueue->queue(tasks[i]); |
| 270 | } |
| 271 | |
| 272 | if (options.has_plugins()) |
| 273 | { |
| 274 | Task_token* next_blocker = new Task_token(true); |
| 275 | next_blocker->add_blocker(); |
| 276 | workqueue->queue(new Plugin_hook(options, input_objects, symtab, layout, |
| 277 | &search_path, mapfile, this_blocker, |
| 278 | next_blocker)); |
| 279 | this_blocker = next_blocker; |
| 280 | } |
| 281 | |
| 282 | if (options.relocatable() |
| 283 | && (options.gc_sections() || options.icf_enabled())) |
| 284 | gold_error(_("cannot mix -r with --gc-sections or --icf")); |
| 285 | |
| 286 | if (options.gc_sections() || options.icf_enabled()) |
| 287 | { |
| 288 | workqueue->queue(new Task_function(new Gc_runner(options, |
| 289 | input_objects, |
| 290 | symtab, |
| 291 | layout, |
| 292 | mapfile), |
| 293 | this_blocker, |
| 294 | "Task_function Gc_runner")); |
| 295 | } |
| 296 | else |
| 297 | { |
| 298 | workqueue->queue(new Task_function(new Middle_runner(options, |
| 299 | input_objects, |
| 300 | symtab, |
| 301 | layout, |
| 302 | mapfile), |
| 303 | this_blocker, |
| 304 | "Task_function Middle_runner")); |
| 305 | } |
| 306 | } |
| 307 | |
| 308 | // Process an incremental input file: if it is unchanged from the previous |
| 309 | // link, return a task to add its symbols from the base file's incremental |
| 310 | // info; if it has changed, return a normal Read_symbols task. We create a |
| 311 | // task for every input file, if only to report the file for rebuilding the |
| 312 | // incremental info. |
| 313 | |
| 314 | static Task* |
| 315 | process_incremental_input(Incremental_binary* ibase, |
| 316 | unsigned int input_file_index, |
| 317 | Input_objects* input_objects, |
| 318 | Symbol_table* symtab, |
| 319 | Layout* layout, |
| 320 | Dirsearch* search_path, |
| 321 | Mapfile* mapfile, |
| 322 | Task_token* this_blocker, |
| 323 | Task_token* next_blocker) |
| 324 | { |
| 325 | const Incremental_binary::Input_reader* input_reader = |
| 326 | ibase->get_input_reader(input_file_index); |
| 327 | Incremental_input_type input_type = input_reader->type(); |
| 328 | |
| 329 | // Get the input argument corresponding to this input file, matching on |
| 330 | // the argument serial number. If the input file cannot be matched |
| 331 | // to an existing input argument, synthesize a new one. |
| 332 | const Input_argument* input_argument = |
| 333 | ibase->get_input_argument(input_file_index); |
| 334 | if (input_argument == NULL) |
| 335 | { |
| 336 | Input_file_argument file(input_reader->filename(), |
| 337 | Input_file_argument::INPUT_FILE_TYPE_FILE, |
| 338 | "", false, parameters->options()); |
| 339 | Input_argument* arg = new Input_argument(file); |
| 340 | arg->set_script_info(ibase->get_script_info(input_file_index)); |
| 341 | input_argument = arg; |
| 342 | } |
| 343 | |
| 344 | gold_debug(DEBUG_INCREMENTAL, "Incremental object: %s, type %d", |
| 345 | input_reader->filename(), input_type); |
| 346 | |
| 347 | if (input_type == INCREMENTAL_INPUT_SCRIPT) |
| 348 | { |
| 349 | // Incremental_binary::check_inputs should have cancelled the |
| 350 | // incremental update if the script has changed. |
| 351 | gold_assert(!ibase->file_has_changed(input_file_index)); |
| 352 | return new Check_script(layout, ibase, input_file_index, input_reader, |
| 353 | this_blocker, next_blocker); |
| 354 | } |
| 355 | |
| 356 | if (input_type == INCREMENTAL_INPUT_ARCHIVE) |
| 357 | { |
| 358 | Incremental_library* lib = ibase->get_library(input_file_index); |
| 359 | gold_assert(lib != NULL); |
| 360 | if (lib->filename() == "/group/" |
| 361 | || !ibase->file_has_changed(input_file_index)) |
| 362 | { |
| 363 | // Queue a task to check that no references have been added to any |
| 364 | // of the library's unused symbols. |
| 365 | return new Check_library(symtab, layout, ibase, input_file_index, |
| 366 | input_reader, this_blocker, next_blocker); |
| 367 | } |
| 368 | else |
| 369 | { |
| 370 | // Queue a Read_symbols task to process the archive normally. |
| 371 | return new Read_symbols(input_objects, symtab, layout, search_path, |
| 372 | 0, mapfile, input_argument, NULL, NULL, |
| 373 | this_blocker, next_blocker); |
| 374 | } |
| 375 | } |
| 376 | |
| 377 | if (input_type == INCREMENTAL_INPUT_ARCHIVE_MEMBER) |
| 378 | { |
| 379 | // For archive members, check the timestamp of the containing archive. |
| 380 | Incremental_library* lib = ibase->get_library(input_file_index); |
| 381 | gold_assert(lib != NULL); |
| 382 | // Process members of a --start-lib/--end-lib group as normal objects. |
| 383 | if (lib->filename() != "/group/") |
| 384 | { |
| 385 | if (ibase->file_has_changed(lib->input_file_index())) |
| 386 | { |
| 387 | return new Read_member(input_objects, symtab, layout, mapfile, |
| 388 | input_reader, this_blocker, next_blocker); |
| 389 | } |
| 390 | else |
| 391 | { |
| 392 | // The previous contributions from this file will be kept. |
| 393 | // Mark the pieces of output sections contributed by this |
| 394 | // object. |
| 395 | ibase->reserve_layout(input_file_index); |
| 396 | Object* obj = make_sized_incremental_object(ibase, |
| 397 | input_file_index, |
| 398 | input_type, |
| 399 | input_reader); |
| 400 | return new Add_symbols(input_objects, symtab, layout, |
| 401 | search_path, 0, mapfile, input_argument, |
| 402 | obj, lib, NULL, this_blocker, |
| 403 | next_blocker); |
| 404 | } |
| 405 | } |
| 406 | } |
| 407 | |
| 408 | // Normal object file or shared library. Check if the file has changed |
| 409 | // since the last incremental link. |
| 410 | if (ibase->file_has_changed(input_file_index)) |
| 411 | { |
| 412 | return new Read_symbols(input_objects, symtab, layout, search_path, 0, |
| 413 | mapfile, input_argument, NULL, NULL, |
| 414 | this_blocker, next_blocker); |
| 415 | } |
| 416 | else |
| 417 | { |
| 418 | // The previous contributions from this file will be kept. |
| 419 | // Mark the pieces of output sections contributed by this object. |
| 420 | ibase->reserve_layout(input_file_index); |
| 421 | Object* obj = make_sized_incremental_object(ibase, |
| 422 | input_file_index, |
| 423 | input_type, |
| 424 | input_reader); |
| 425 | return new Add_symbols(input_objects, symtab, layout, search_path, 0, |
| 426 | mapfile, input_argument, obj, NULL, NULL, |
| 427 | this_blocker, next_blocker); |
| 428 | } |
| 429 | } |
| 430 | |
| 431 | // Queue up a set of tasks to be done before queueing the middle set |
| 432 | // of tasks. This is only necessary when garbage collection |
| 433 | // (--gc-sections) of unused sections is desired. The relocs are read |
| 434 | // and processed here early to determine the garbage sections before the |
| 435 | // relocs can be scanned in later tasks. |
| 436 | |
| 437 | void |
| 438 | queue_middle_gc_tasks(const General_options& options, |
| 439 | const Task* , |
| 440 | const Input_objects* input_objects, |
| 441 | Symbol_table* symtab, |
| 442 | Layout* layout, |
| 443 | Workqueue* workqueue, |
| 444 | Mapfile* mapfile) |
| 445 | { |
| 446 | // Read_relocs for all the objects must be done and processed to find |
| 447 | // unused sections before any scanning of the relocs can take place. |
| 448 | Task_token* this_blocker = NULL; |
| 449 | for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); |
| 450 | p != input_objects->relobj_end(); |
| 451 | ++p) |
| 452 | { |
| 453 | Task_token* next_blocker = new Task_token(true); |
| 454 | next_blocker->add_blocker(); |
| 455 | workqueue->queue(new Read_relocs(symtab, layout, *p, this_blocker, |
| 456 | next_blocker)); |
| 457 | this_blocker = next_blocker; |
| 458 | } |
| 459 | |
| 460 | // If we are given only archives in input, we have no regular |
| 461 | // objects and THIS_BLOCKER is NULL here. Create a dummy |
| 462 | // blocker here so that we can run the middle tasks immediately. |
| 463 | if (this_blocker == NULL) |
| 464 | { |
| 465 | gold_assert(input_objects->number_of_relobjs() == 0); |
| 466 | this_blocker = new Task_token(true); |
| 467 | } |
| 468 | |
| 469 | workqueue->queue(new Task_function(new Middle_runner(options, |
| 470 | input_objects, |
| 471 | symtab, |
| 472 | layout, |
| 473 | mapfile), |
| 474 | this_blocker, |
| 475 | "Task_function Middle_runner")); |
| 476 | } |
| 477 | |
| 478 | // Queue up the middle set of tasks. These are the tasks which run |
| 479 | // after all the input objects have been found and all the symbols |
| 480 | // have been read, but before we lay out the output file. |
| 481 | |
| 482 | void |
| 483 | queue_middle_tasks(const General_options& options, |
| 484 | const Task* task, |
| 485 | const Input_objects* input_objects, |
| 486 | Symbol_table* symtab, |
| 487 | Layout* layout, |
| 488 | Workqueue* workqueue, |
| 489 | Mapfile* mapfile) |
| 490 | { |
| 491 | Timer* timer = parameters->timer(); |
| 492 | if (timer != NULL) |
| 493 | timer->stamp(0); |
| 494 | |
| 495 | // We have to support the case of not seeing any input objects, and |
| 496 | // generate an empty file. Existing builds depend on being able to |
| 497 | // pass an empty archive to the linker and get an empty object file |
| 498 | // out. In order to do this we need to use a default target. |
| 499 | if (input_objects->number_of_input_objects() == 0 |
| 500 | && layout->incremental_base() == NULL) |
| 501 | parameters_force_valid_target(); |
| 502 | |
| 503 | // Add any symbols named with -u options to the symbol table. |
| 504 | symtab->add_undefined_symbols_from_command_line(layout); |
| 505 | |
| 506 | // If garbage collection was chosen, relocs have been read and processed |
| 507 | // at this point by pre_middle_tasks. Layout can then be done for all |
| 508 | // objects. |
| 509 | if (parameters->options().gc_sections()) |
| 510 | { |
| 511 | // Find the start symbol if any. |
| 512 | Symbol* sym = symtab->lookup(parameters->entry()); |
| 513 | if (sym != NULL) |
| 514 | symtab->gc_mark_symbol(sym); |
| 515 | sym = symtab->lookup(parameters->options().init()); |
| 516 | if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj()) |
| 517 | symtab->gc_mark_symbol(sym); |
| 518 | sym = symtab->lookup(parameters->options().fini()); |
| 519 | if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj()) |
| 520 | symtab->gc_mark_symbol(sym); |
| 521 | // Symbols named with -u should not be considered garbage. |
| 522 | symtab->gc_mark_undef_symbols(layout); |
| 523 | gold_assert(symtab->gc() != NULL); |
| 524 | // Do a transitive closure on all references to determine the worklist. |
| 525 | symtab->gc()->do_transitive_closure(); |
| 526 | } |
| 527 | |
| 528 | // If identical code folding (--icf) is chosen it makes sense to do it |
| 529 | // only after garbage collection (--gc-sections) as we do not want to |
| 530 | // be folding sections that will be garbage. |
| 531 | if (parameters->options().icf_enabled()) |
| 532 | { |
| 533 | symtab->icf()->find_identical_sections(input_objects, symtab); |
| 534 | } |
| 535 | |
| 536 | // Call Object::layout for the second time to determine the |
| 537 | // output_sections for all referenced input sections. When |
| 538 | // --gc-sections or --icf is turned on, or when certain input |
| 539 | // sections have to be mapped to unique segments, Object::layout |
| 540 | // is called twice. It is called the first time when symbols |
| 541 | // are added. |
| 542 | if (parameters->options().gc_sections() |
| 543 | || parameters->options().icf_enabled() |
| 544 | || layout->is_unique_segment_for_sections_specified()) |
| 545 | { |
| 546 | for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); |
| 547 | p != input_objects->relobj_end(); |
| 548 | ++p) |
| 549 | { |
| 550 | Task_lock_obj<Object> tlo(task, *p); |
| 551 | (*p)->layout(symtab, layout, NULL); |
| 552 | } |
| 553 | } |
| 554 | |
| 555 | // Layout deferred objects due to plugins. |
| 556 | if (parameters->options().has_plugins()) |
| 557 | { |
| 558 | Plugin_manager* plugins = parameters->options().plugins(); |
| 559 | gold_assert(plugins != NULL); |
| 560 | plugins->layout_deferred_objects(); |
| 561 | } |
| 562 | |
| 563 | // Finalize the .eh_frame section. |
| 564 | layout->finalize_eh_frame_section(); |
| 565 | |
| 566 | /* If plugins have specified a section order, re-arrange input sections |
| 567 | according to a specified section order. If --section-ordering-file is |
| 568 | also specified, do not do anything here. */ |
| 569 | if (parameters->options().has_plugins() |
| 570 | && layout->is_section_ordering_specified() |
| 571 | && !parameters->options().section_ordering_file ()) |
| 572 | { |
| 573 | for (Layout::Section_list::const_iterator p |
| 574 | = layout->section_list().begin(); |
| 575 | p != layout->section_list().end(); |
| 576 | ++p) |
| 577 | (*p)->update_section_layout(layout->get_section_order_map()); |
| 578 | } |
| 579 | |
| 580 | if (parameters->options().gc_sections() |
| 581 | || parameters->options().icf_enabled()) |
| 582 | { |
| 583 | for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); |
| 584 | p != input_objects->relobj_end(); |
| 585 | ++p) |
| 586 | { |
| 587 | // Update the value of output_section stored in rd. |
| 588 | Read_relocs_data* rd = (*p)->get_relocs_data(); |
| 589 | for (Read_relocs_data::Relocs_list::iterator q = rd->relocs.begin(); |
| 590 | q != rd->relocs.end(); |
| 591 | ++q) |
| 592 | { |
| 593 | q->output_section = (*p)->output_section(q->data_shndx); |
| 594 | q->needs_special_offset_handling = |
| 595 | (*p)->is_output_section_offset_invalid(q->data_shndx); |
| 596 | } |
| 597 | } |
| 598 | } |
| 599 | |
| 600 | int thread_count = options.thread_count_middle(); |
| 601 | if (thread_count == 0) |
| 602 | thread_count = std::max(2, input_objects->number_of_input_objects()); |
| 603 | workqueue->set_thread_count(thread_count); |
| 604 | |
| 605 | // Now we have seen all the input files. |
| 606 | const bool doing_static_link = |
| 607 | (!input_objects->any_dynamic() |
| 608 | && !parameters->options().output_is_position_independent()); |
| 609 | set_parameters_doing_static_link(doing_static_link); |
| 610 | if (!doing_static_link && options.is_static()) |
| 611 | { |
| 612 | // We print out just the first .so we see; there may be others. |
| 613 | gold_assert(input_objects->dynobj_begin() != input_objects->dynobj_end()); |
| 614 | gold_error(_("cannot mix -static with dynamic object %s"), |
| 615 | (*input_objects->dynobj_begin())->name().c_str()); |
| 616 | } |
| 617 | if (!doing_static_link && parameters->options().relocatable()) |
| 618 | gold_fatal(_("cannot mix -r with dynamic object %s"), |
| 619 | (*input_objects->dynobj_begin())->name().c_str()); |
| 620 | if (!doing_static_link |
| 621 | && options.oformat_enum() != General_options::OBJECT_FORMAT_ELF) |
| 622 | gold_fatal(_("cannot use non-ELF output format with dynamic object %s"), |
| 623 | (*input_objects->dynobj_begin())->name().c_str()); |
| 624 | |
| 625 | if (parameters->options().relocatable()) |
| 626 | { |
| 627 | Input_objects::Relobj_iterator p = input_objects->relobj_begin(); |
| 628 | if (p != input_objects->relobj_end()) |
| 629 | { |
| 630 | bool uses_split_stack = (*p)->uses_split_stack(); |
| 631 | for (++p; p != input_objects->relobj_end(); ++p) |
| 632 | { |
| 633 | if ((*p)->uses_split_stack() != uses_split_stack) |
| 634 | { |
| 635 | const char *name1 |
| 636 | = (*input_objects->relobj_begin())->name().c_str(); |
| 637 | const char *name2 = (*p)->name().c_str(); |
| 638 | const char *name_split = uses_split_stack ? name1 : name2; |
| 639 | const char *name_nosplit = uses_split_stack ? name2 : name1; |
| 640 | gold_fatal(_("cannot mix split-stack '%s' and " |
| 641 | "non-split-stack '%s' when using -r"), |
| 642 | name_split, name_nosplit); |
| 643 | } |
| 644 | } |
| 645 | } |
| 646 | } |
| 647 | |
| 648 | // For incremental updates, record the existing GOT and PLT entries, |
| 649 | // and the COPY relocations. |
| 650 | if (parameters->incremental_update()) |
| 651 | { |
| 652 | Incremental_binary* ibase = layout->incremental_base(); |
| 653 | ibase->process_got_plt(symtab, layout); |
| 654 | ibase->emit_copy_relocs(symtab); |
| 655 | } |
| 656 | |
| 657 | if (is_debugging_enabled(DEBUG_SCRIPT)) |
| 658 | layout->script_options()->print(stderr); |
| 659 | |
| 660 | // For each dynamic object, record whether we've seen all the |
| 661 | // dynamic objects that it depends upon. |
| 662 | input_objects->check_dynamic_dependencies(); |
| 663 | |
| 664 | // Do the --no-undefined-version check. |
| 665 | if (!parameters->options().undefined_version()) |
| 666 | { |
| 667 | Script_options* so = layout->script_options(); |
| 668 | so->version_script_info()->check_unmatched_names(symtab); |
| 669 | } |
| 670 | |
| 671 | // Create any automatic note sections. |
| 672 | layout->create_notes(); |
| 673 | |
| 674 | // Create any output sections required by any linker script. |
| 675 | layout->create_script_sections(); |
| 676 | |
| 677 | // Define some sections and symbols needed for a dynamic link. This |
| 678 | // handles some cases we want to see before we read the relocs. |
| 679 | layout->create_initial_dynamic_sections(symtab); |
| 680 | |
| 681 | // Define symbols from any linker scripts. |
| 682 | layout->define_script_symbols(symtab); |
| 683 | |
| 684 | // TODO(csilvers): figure out a more principled way to get the target |
| 685 | Target* target = const_cast<Target*>(¶meters->target()); |
| 686 | |
| 687 | // Attach sections to segments. |
| 688 | layout->attach_sections_to_segments(target); |
| 689 | |
| 690 | if (!parameters->options().relocatable()) |
| 691 | { |
| 692 | // Predefine standard symbols. |
| 693 | define_standard_symbols(symtab, layout); |
| 694 | |
| 695 | // Define __start and __stop symbols for output sections where |
| 696 | // appropriate. |
| 697 | layout->define_section_symbols(symtab); |
| 698 | |
| 699 | // Define target-specific symbols. |
| 700 | target->define_standard_symbols(symtab, layout); |
| 701 | } |
| 702 | |
| 703 | // Make sure we have symbols for any required group signatures. |
| 704 | layout->define_group_signatures(symtab); |
| 705 | |
| 706 | Task_token* this_blocker = NULL; |
| 707 | |
| 708 | // Allocate common symbols. We use a blocker to run this before the |
| 709 | // Scan_relocs tasks, because it writes to the symbol table just as |
| 710 | // they do. |
| 711 | if (parameters->options().define_common()) |
| 712 | { |
| 713 | this_blocker = new Task_token(true); |
| 714 | this_blocker->add_blocker(); |
| 715 | workqueue->queue(new Allocate_commons_task(symtab, layout, mapfile, |
| 716 | this_blocker)); |
| 717 | } |
| 718 | |
| 719 | // If doing garbage collection, the relocations have already been read. |
| 720 | // Otherwise, read and scan the relocations. |
| 721 | if (parameters->options().gc_sections() |
| 722 | || parameters->options().icf_enabled()) |
| 723 | { |
| 724 | for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); |
| 725 | p != input_objects->relobj_end(); |
| 726 | ++p) |
| 727 | { |
| 728 | Task_token* next_blocker = new Task_token(true); |
| 729 | next_blocker->add_blocker(); |
| 730 | workqueue->queue(new Scan_relocs(symtab, layout, *p, |
| 731 | (*p)->get_relocs_data(), |
| 732 | this_blocker, next_blocker)); |
| 733 | this_blocker = next_blocker; |
| 734 | } |
| 735 | } |
| 736 | else |
| 737 | { |
| 738 | // Read the relocations of the input files. We do this to find |
| 739 | // which symbols are used by relocations which require a GOT and/or |
| 740 | // a PLT entry, or a COPY reloc. When we implement garbage |
| 741 | // collection we will do it here by reading the relocations in a |
| 742 | // breadth first search by references. |
| 743 | // |
| 744 | // We could also read the relocations during the first pass, and |
| 745 | // mark symbols at that time. That is how the old GNU linker works. |
| 746 | // Doing that is more complex, since we may later decide to discard |
| 747 | // some of the sections, and thus change our minds about the types |
| 748 | // of references made to the symbols. |
| 749 | for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); |
| 750 | p != input_objects->relobj_end(); |
| 751 | ++p) |
| 752 | { |
| 753 | Task_token* next_blocker = new Task_token(true); |
| 754 | next_blocker->add_blocker(); |
| 755 | workqueue->queue(new Read_relocs(symtab, layout, *p, this_blocker, |
| 756 | next_blocker)); |
| 757 | this_blocker = next_blocker; |
| 758 | } |
| 759 | } |
| 760 | |
| 761 | if (this_blocker == NULL) |
| 762 | { |
| 763 | if (input_objects->number_of_relobjs() == 0) |
| 764 | { |
| 765 | // If we are given only archives in input, we have no regular |
| 766 | // objects and THIS_BLOCKER is NULL here. Create a dummy |
| 767 | // blocker here so that we can run the layout task immediately. |
| 768 | this_blocker = new Task_token(true); |
| 769 | } |
| 770 | else |
| 771 | { |
| 772 | // If we failed to open any input files, it's possible for |
| 773 | // THIS_BLOCKER to be NULL here. There's no real point in |
| 774 | // continuing if that happens. |
| 775 | gold_assert(parameters->errors()->error_count() > 0); |
| 776 | gold_exit(GOLD_ERR); |
| 777 | } |
| 778 | } |
| 779 | |
| 780 | // When all those tasks are complete, we can start laying out the |
| 781 | // output file. |
| 782 | workqueue->queue(new Task_function(new Layout_task_runner(options, |
| 783 | input_objects, |
| 784 | symtab, |
| 785 | target, |
| 786 | layout, |
| 787 | mapfile), |
| 788 | this_blocker, |
| 789 | "Task_function Layout_task_runner")); |
| 790 | } |
| 791 | |
| 792 | // Queue up the final set of tasks. This is called at the end of |
| 793 | // Layout_task. |
| 794 | |
| 795 | void |
| 796 | queue_final_tasks(const General_options& options, |
| 797 | const Input_objects* input_objects, |
| 798 | const Symbol_table* symtab, |
| 799 | Layout* layout, |
| 800 | Workqueue* workqueue, |
| 801 | Output_file* of) |
| 802 | { |
| 803 | Timer* timer = parameters->timer(); |
| 804 | if (timer != NULL) |
| 805 | timer->stamp(1); |
| 806 | |
| 807 | int thread_count = options.thread_count_final(); |
| 808 | if (thread_count == 0) |
| 809 | thread_count = std::max(2, input_objects->number_of_input_objects()); |
| 810 | workqueue->set_thread_count(thread_count); |
| 811 | |
| 812 | bool any_postprocessing_sections = layout->any_postprocessing_sections(); |
| 813 | |
| 814 | // Use a blocker to wait until all the input sections have been |
| 815 | // written out. |
| 816 | Task_token* input_sections_blocker = NULL; |
| 817 | if (!any_postprocessing_sections) |
| 818 | { |
| 819 | input_sections_blocker = new Task_token(true); |
| 820 | // Write_symbols_task, Relocate_tasks. |
| 821 | input_sections_blocker->add_blocker(); |
| 822 | input_sections_blocker->add_blockers(input_objects->number_of_relobjs()); |
| 823 | } |
| 824 | |
| 825 | // Use a blocker to block any objects which have to wait for the |
| 826 | // output sections to complete before they can apply relocations. |
| 827 | Task_token* output_sections_blocker = new Task_token(true); |
| 828 | output_sections_blocker->add_blocker(); |
| 829 | |
| 830 | // Use a blocker to block the final cleanup task. |
| 831 | Task_token* final_blocker = new Task_token(true); |
| 832 | // Write_symbols_task, Write_sections_task, Write_data_task, |
| 833 | // Relocate_tasks. |
| 834 | final_blocker->add_blockers(3); |
| 835 | final_blocker->add_blockers(input_objects->number_of_relobjs()); |
| 836 | if (!any_postprocessing_sections) |
| 837 | final_blocker->add_blocker(); |
| 838 | |
| 839 | // Queue a task to write out the symbol table. |
| 840 | workqueue->queue(new Write_symbols_task(layout, |
| 841 | symtab, |
| 842 | input_objects, |
| 843 | layout->sympool(), |
| 844 | layout->dynpool(), |
| 845 | of, |
| 846 | final_blocker)); |
| 847 | |
| 848 | // Queue a task to write out the output sections. |
| 849 | workqueue->queue(new Write_sections_task(layout, of, output_sections_blocker, |
| 850 | input_sections_blocker, |
| 851 | final_blocker)); |
| 852 | |
| 853 | // Queue a task to write out everything else. |
| 854 | workqueue->queue(new Write_data_task(layout, symtab, of, final_blocker)); |
| 855 | |
| 856 | // Queue a task for each input object to relocate the sections and |
| 857 | // write out the local symbols. |
| 858 | for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); |
| 859 | p != input_objects->relobj_end(); |
| 860 | ++p) |
| 861 | workqueue->queue(new Relocate_task(symtab, layout, *p, of, |
| 862 | input_sections_blocker, |
| 863 | output_sections_blocker, |
| 864 | final_blocker)); |
| 865 | |
| 866 | // Queue a task to write out the output sections which depend on |
| 867 | // input sections. If there are any sections which require |
| 868 | // postprocessing, then we need to do this last, since it may resize |
| 869 | // the output file. |
| 870 | if (!any_postprocessing_sections) |
| 871 | { |
| 872 | Task* t = new Write_after_input_sections_task(layout, of, |
| 873 | input_sections_blocker, |
| 874 | final_blocker); |
| 875 | workqueue->queue(t); |
| 876 | } |
| 877 | else |
| 878 | { |
| 879 | Task_token* new_final_blocker = new Task_token(true); |
| 880 | new_final_blocker->add_blocker(); |
| 881 | Task* t = new Write_after_input_sections_task(layout, of, |
| 882 | final_blocker, |
| 883 | new_final_blocker); |
| 884 | workqueue->queue(t); |
| 885 | final_blocker = new_final_blocker; |
| 886 | } |
| 887 | |
| 888 | // Create tasks for tree-style build ID computation, if necessary. |
| 889 | if (strcmp(options.build_id(), "tree") == 0) |
| 890 | { |
| 891 | // Queue a task to compute the build id. This will be blocked by |
| 892 | // FINAL_BLOCKER, and will in turn schedule the task to close |
| 893 | // the output file. |
| 894 | workqueue->queue(new Task_function(new Build_id_task_runner(&options, |
| 895 | layout, |
| 896 | of), |
| 897 | final_blocker, |
| 898 | "Task_function Build_id_task_runner")); |
| 899 | } |
| 900 | else |
| 901 | { |
| 902 | // Queue a task to close the output file. This will be blocked by |
| 903 | // FINAL_BLOCKER. |
| 904 | workqueue->queue(new Task_function(new Close_task_runner(&options, layout, |
| 905 | of, NULL, 0), |
| 906 | final_blocker, |
| 907 | "Task_function Close_task_runner")); |
| 908 | } |
| 909 | |
| 910 | } |
| 911 | |
| 912 | } // End namespace gold. |