1 // Copyright 2012 the V8 project authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 // This file defines all of the flags. It is separated into different section, 6 // for Debug, Release, Logging and Profiling, etc. To add a new flag, find the 7 // correct section, and use one of the DEFINE_ macros, without a trailing ';'. 8 // 9 // This include does not have a guard, because it is a template-style include, 10 // which can be included multiple times in different modes. It expects to have 11 // a mode defined before it's included. The modes are FLAG_MODE_... below: 12 // 13 // PRESUBMIT_INTENTIONALLY_MISSING_INCLUDE_GUARD 14 15 #define DEFINE_IMPLICATION(whenflag, thenflag) \ 16 DEFINE_VALUE_IMPLICATION(whenflag, thenflag, true) 17 18 // A weak implication will be overwritten by a normal implication or by an 19 // explicit flag. 20 #define DEFINE_WEAK_IMPLICATION(whenflag, thenflag) \ 21 DEFINE_WEAK_VALUE_IMPLICATION(whenflag, thenflag, true) 22 23 #define DEFINE_NEG_IMPLICATION(whenflag, thenflag) \ 24 DEFINE_VALUE_IMPLICATION(whenflag, thenflag, false) 25 26 #define DEFINE_NEG_NEG_IMPLICATION(whenflag, thenflag) \ 27 DEFINE_NEG_VALUE_IMPLICATION(whenflag, thenflag, false) 28 29 // We want to declare the names of the variables for the header file. Normally 30 // this will just be an extern declaration, but for a readonly flag we let the 31 // compiler make better optimizations by giving it the value. 32 #if defined(FLAG_MODE_DECLARE) 33 #define FLAG_FULL(ftype, ctype, nam, def, cmt) \ 34 V8_EXPORT_PRIVATE extern ctype FLAG_##nam; 35 #define FLAG_READONLY(ftype, ctype, nam, def, cmt) \ 36 static constexpr ctype FLAG_##nam = def; 37 38 // We want to supply the actual storage and value for the flag variable in the 39 // .cc file. We only do this for writable flags. 40 #elif defined(FLAG_MODE_DEFINE) 41 #ifdef USING_V8_SHARED 42 #define FLAG_FULL(ftype, ctype, nam, def, cmt) \ 43 V8_EXPORT_PRIVATE extern ctype FLAG_##nam; 44 #else 45 #define FLAG_FULL(ftype, ctype, nam, def, cmt) \ 46 V8_EXPORT_PRIVATE ctype FLAG_##nam = def; 47 #endif 48 49 // We need to define all of our default values so that the Flag structure can 50 // access them by pointer. These are just used internally inside of one .cc, 51 // for MODE_META, so there is no impact on the flags interface. 52 #elif defined(FLAG_MODE_DEFINE_DEFAULTS) 53 #define FLAG_FULL(ftype, ctype, nam, def, cmt) \ 54 static constexpr ctype FLAGDEFAULT_##nam = def; 55 56 // We want to write entries into our meta data table, for internal parsing and 57 // printing / etc in the flag parser code. We only do this for writable flags. 58 #elif defined(FLAG_MODE_META) 59 #define FLAG_FULL(ftype, ctype, nam, def, cmt) \ 60 {Flag::TYPE_##ftype, #nam, &FLAG_##nam, &FLAGDEFAULT_##nam, cmt, false}, 61 #define FLAG_ALIAS(ftype, ctype, alias, nam) \ 62 {Flag::TYPE_##ftype, #alias, &FLAG_##nam, &FLAGDEFAULT_##nam, \ 63 "alias for --" #nam, false}, 64 65 // We produce the code to set flags when it is implied by another flag. 66 #elif defined(FLAG_MODE_DEFINE_IMPLICATIONS) 67 #define DEFINE_VALUE_IMPLICATION(whenflag, thenflag, value) \ 68 changed |= TriggerImplication(FLAG_##whenflag, #whenflag, &FLAG_##thenflag, \ 69 value, false); 70 71 // A weak implication will be overwritten by a normal implication or by an 72 // explicit flag. 73 #define DEFINE_WEAK_VALUE_IMPLICATION(whenflag, thenflag, value) \ 74 changed |= TriggerImplication(FLAG_##whenflag, #whenflag, &FLAG_##thenflag, \ 75 value, true); 76 77 #define DEFINE_GENERIC_IMPLICATION(whenflag, statement) \ 78 if (FLAG_##whenflag) statement; 79 80 #define DEFINE_NEG_VALUE_IMPLICATION(whenflag, thenflag, value) \ 81 changed |= TriggerImplication(!FLAG_##whenflag, #whenflag, &FLAG_##thenflag, \ 82 value, false); 83 84 // We apply a generic macro to the flags. 85 #elif defined(FLAG_MODE_APPLY) 86 87 #define FLAG_FULL FLAG_MODE_APPLY 88 89 #else 90 #error No mode supplied when including flags.defs 91 #endif 92 93 // Dummy defines for modes where it is not relevant. 94 #ifndef FLAG_FULL 95 #define FLAG_FULL(ftype, ctype, nam, def, cmt) 96 #endif 97 98 #ifndef FLAG_READONLY 99 #define FLAG_READONLY(ftype, ctype, nam, def, cmt) 100 #endif 101 102 #ifndef FLAG_ALIAS 103 #define FLAG_ALIAS(ftype, ctype, alias, nam) 104 #endif 105 106 #ifndef DEFINE_VALUE_IMPLICATION 107 #define DEFINE_VALUE_IMPLICATION(whenflag, thenflag, value) 108 #endif 109 110 #ifndef DEFINE_WEAK_VALUE_IMPLICATION 111 #define DEFINE_WEAK_VALUE_IMPLICATION(whenflag, thenflag, value) 112 #endif 113 114 #ifndef DEFINE_GENERIC_IMPLICATION 115 #define DEFINE_GENERIC_IMPLICATION(whenflag, statement) 116 #endif 117 118 #ifndef DEFINE_NEG_VALUE_IMPLICATION 119 #define DEFINE_NEG_VALUE_IMPLICATION(whenflag, thenflag, value) 120 #endif 121 122 #define COMMA , 123 124 #ifdef FLAG_MODE_DECLARE 125 126 struct MaybeBoolFlag { CreateMaybeBoolFlag127 static MaybeBoolFlag Create(bool has_value, bool value) { 128 MaybeBoolFlag flag; 129 flag.has_value = has_value; 130 flag.value = value; 131 return flag; 132 } 133 bool has_value; 134 bool value; 135 136 bool operator!=(const MaybeBoolFlag& other) const { 137 return has_value != other.has_value || value != other.value; 138 } 139 }; 140 #endif 141 142 #ifdef DEBUG 143 #define DEBUG_BOOL true 144 #else 145 #define DEBUG_BOOL false 146 #endif 147 148 #ifdef V8_COMPRESS_POINTERS 149 #define COMPRESS_POINTERS_BOOL true 150 #else 151 #define COMPRESS_POINTERS_BOOL false 152 #endif 153 154 #ifdef V8_MAP_PACKING 155 #define V8_MAP_PACKING_BOOL true 156 #else 157 #define V8_MAP_PACKING_BOOL false 158 #endif 159 160 #ifdef V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE 161 #define COMPRESS_POINTERS_IN_ISOLATE_CAGE_BOOL true 162 #else 163 #define COMPRESS_POINTERS_IN_ISOLATE_CAGE_BOOL false 164 #endif 165 166 #ifdef V8_COMPRESS_POINTERS_IN_SHARED_CAGE 167 #define COMPRESS_POINTERS_IN_SHARED_CAGE_BOOL true 168 #else 169 #define COMPRESS_POINTERS_IN_SHARED_CAGE_BOOL false 170 #endif 171 172 #ifdef V8_HEAP_SANDBOX 173 #define V8_HEAP_SANDBOX_BOOL true 174 #else 175 #define V8_HEAP_SANDBOX_BOOL false 176 #endif 177 178 #ifdef V8_VIRTUAL_MEMORY_CAGE 179 #define V8_VIRTUAL_MEMORY_CAGE_BOOL true 180 #else 181 #define V8_VIRTUAL_MEMORY_CAGE_BOOL false 182 #endif 183 184 // D8's MultiMappedAllocator is only available on Linux, and only if the virtual 185 // memory cage is not enabled. 186 #if V8_OS_LINUX && !V8_VIRTUAL_MEMORY_CAGE_BOOL 187 #define MULTI_MAPPED_ALLOCATOR_AVAILABLE true 188 #else 189 #define MULTI_MAPPED_ALLOCATOR_AVAILABLE false 190 #endif 191 192 #ifdef V8_ENABLE_CONTROL_FLOW_INTEGRITY 193 #define ENABLE_CONTROL_FLOW_INTEGRITY_BOOL true 194 #else 195 #define ENABLE_CONTROL_FLOW_INTEGRITY_BOOL false 196 #endif 197 198 #if V8_TARGET_ARCH_IA32 || V8_TARGET_ARCH_X64 || V8_TARGET_ARCH_ARM64 || \ 199 V8_TARGET_ARCH_ARM || V8_TARGET_ARCH_RISCV64 || V8_TARGET_ARCH_MIPS64 || \ 200 V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_LOONG64 201 #define ENABLE_SPARKPLUG true 202 #else 203 // TODO(v8:11421): Enable Sparkplug for other architectures 204 #define ENABLE_SPARKPLUG false 205 #endif 206 207 #if ENABLE_SPARKPLUG && !defined(ANDROID) 208 // Enable Sparkplug by default on desktop-only. 209 #define ENABLE_SPARKPLUG_BY_DEFAULT true 210 #else 211 #define ENABLE_SPARKPLUG_BY_DEFAULT false 212 #endif 213 214 #if defined(V8_OS_MACOSX) && defined(V8_HOST_ARCH_ARM64) 215 // Must be enabled on M1. 216 #define MUST_WRITE_PROTECT_CODE_MEMORY true 217 #else 218 #define MUST_WRITE_PROTECT_CODE_MEMORY false 219 #endif 220 221 // Supported ARM configurations are: 222 // "armv6": ARMv6 + VFPv2 223 // "armv7": ARMv7 + VFPv3-D32 + NEON 224 // "armv7+sudiv": ARMv7 + VFPv4-D32 + NEON + SUDIV 225 // "armv8": ARMv8 (including all of the above) 226 #if !defined(ARM_TEST_NO_FEATURE_PROBE) || \ 227 (defined(CAN_USE_ARMV8_INSTRUCTIONS) && \ 228 defined(CAN_USE_ARMV7_INSTRUCTIONS) && defined(CAN_USE_SUDIV) && \ 229 defined(CAN_USE_NEON) && defined(CAN_USE_VFP3_INSTRUCTIONS)) 230 #define ARM_ARCH_DEFAULT "armv8" 231 #elif defined(CAN_USE_ARMV7_INSTRUCTIONS) && defined(CAN_USE_SUDIV) && \ 232 defined(CAN_USE_NEON) && defined(CAN_USE_VFP3_INSTRUCTIONS) 233 #define ARM_ARCH_DEFAULT "armv7+sudiv" 234 #elif defined(CAN_USE_ARMV7_INSTRUCTIONS) && defined(CAN_USE_NEON) && \ 235 defined(CAN_USE_VFP3_INSTRUCTIONS) 236 #define ARM_ARCH_DEFAULT "armv7" 237 #else 238 #define ARM_ARCH_DEFAULT "armv6" 239 #endif 240 241 #ifdef V8_OS_WIN 242 #define ENABLE_LOG_COLOUR false 243 #else 244 #define ENABLE_LOG_COLOUR true 245 #endif 246 247 #define DEFINE_BOOL(nam, def, cmt) FLAG(BOOL, bool, nam, def, cmt) 248 #define DEFINE_BOOL_READONLY(nam, def, cmt) \ 249 FLAG_READONLY(BOOL, bool, nam, def, cmt) 250 #define DEFINE_MAYBE_BOOL(nam, cmt) \ 251 FLAG(MAYBE_BOOL, MaybeBoolFlag, nam, {false COMMA false}, cmt) 252 #define DEFINE_INT(nam, def, cmt) FLAG(INT, int, nam, def, cmt) 253 #define DEFINE_UINT(nam, def, cmt) FLAG(UINT, unsigned int, nam, def, cmt) 254 #define DEFINE_UINT_READONLY(nam, def, cmt) \ 255 FLAG_READONLY(UINT, unsigned int, nam, def, cmt) 256 #define DEFINE_UINT64(nam, def, cmt) FLAG(UINT64, uint64_t, nam, def, cmt) 257 #define DEFINE_FLOAT(nam, def, cmt) FLAG(FLOAT, double, nam, def, cmt) 258 #define DEFINE_SIZE_T(nam, def, cmt) FLAG(SIZE_T, size_t, nam, def, cmt) 259 #define DEFINE_STRING(nam, def, cmt) FLAG(STRING, const char*, nam, def, cmt) 260 #define DEFINE_ALIAS_BOOL(alias, nam) FLAG_ALIAS(BOOL, bool, alias, nam) 261 #define DEFINE_ALIAS_INT(alias, nam) FLAG_ALIAS(INT, int, alias, nam) 262 #define DEFINE_ALIAS_FLOAT(alias, nam) FLAG_ALIAS(FLOAT, double, alias, nam) 263 #define DEFINE_ALIAS_SIZE_T(alias, nam) FLAG_ALIAS(SIZE_T, size_t, alias, nam) 264 #define DEFINE_ALIAS_STRING(alias, nam) \ 265 FLAG_ALIAS(STRING, const char*, alias, nam) 266 267 #ifdef DEBUG 268 #define DEFINE_DEBUG_BOOL DEFINE_BOOL 269 #else 270 #define DEFINE_DEBUG_BOOL DEFINE_BOOL_READONLY 271 #endif 272 273 // 274 // Flags in all modes. 275 // 276 #define FLAG FLAG_FULL 277 278 // ATTENTION: This is set to true by default in d8. But for API compatibility, 279 // it generally defaults to false. 280 DEFINE_BOOL(abort_on_contradictory_flags, false, 281 "Disallow flags or implications overriding each other.") 282 // This implication is also hard-coded into the flags processing to make sure it 283 // becomes active before we even process subsequent flags. 284 DEFINE_NEG_IMPLICATION(fuzzing, abort_on_contradictory_flags) 285 // This is not really a flag, it affects the interpretation of the next flag but 286 // doesn't become permanently true when specified. This only works for flags 287 // defined in this file, but not for d8 flags defined in src/d8/d8.cc. 288 DEFINE_BOOL(allow_overwriting_for_next_flag, false, 289 "temporary disable flag contradiction to allow overwriting just " 290 "the next flag") 291 292 // Flags for language modes and experimental language features. 293 DEFINE_BOOL(use_strict, false, "enforce strict mode") 294 295 DEFINE_BOOL(harmony, false, "enable all completed harmony features") 296 DEFINE_BOOL(harmony_shipping, true, "enable all shipped harmony features") 297 298 // Update bootstrapper.cc whenever adding a new feature flag. 299 300 // Features that are still work in progress (behind individual flags). 301 #define HARMONY_INPROGRESS_BASE(V) \ 302 V(harmony_weak_refs_with_cleanup_some, \ 303 "harmony weak references with FinalizationRegistry.prototype.cleanupSome") \ 304 V(harmony_import_assertions, "harmony import assertions") \ 305 V(harmony_rab_gsab, \ 306 "harmony ResizableArrayBuffer / GrowableSharedArrayBuffer") \ 307 V(harmony_array_find_last, "harmony array find last helpers") 308 309 #ifdef V8_INTL_SUPPORT 310 #define HARMONY_INPROGRESS(V) HARMONY_INPROGRESS_BASE(V) 311 #else 312 #define HARMONY_INPROGRESS(V) HARMONY_INPROGRESS_BASE(V) 313 #endif 314 315 // Features that are complete (but still behind --harmony/es-staging flag). 316 #define HARMONY_STAGED_BASE(V) 317 318 #ifdef V8_INTL_SUPPORT 319 #define HARMONY_STAGED(V) \ 320 HARMONY_STAGED_BASE(V) \ 321 V(harmony_intl_best_fit_matcher, "Intl BestFitMatcher") \ 322 V(harmony_intl_enumeration, "Intl Enumberation API") \ 323 V(harmony_intl_locale_info, "Intl locale info") 324 #else 325 #define HARMONY_STAGED(V) HARMONY_STAGED_BASE(V) 326 #endif 327 328 // Features that are shipping (turned on by default, but internal flag remains). 329 #define HARMONY_SHIPPING_BASE(V) \ 330 V(harmony_sharedarraybuffer, "harmony sharedarraybuffer") \ 331 V(harmony_atomics, "harmony atomics") \ 332 V(harmony_private_brand_checks, "harmony private brand checks") \ 333 V(harmony_top_level_await, "harmony top level await") \ 334 V(harmony_relative_indexing_methods, "harmony relative indexing methods") \ 335 V(harmony_error_cause, "harmony error cause property") \ 336 V(harmony_object_has_own, "harmony Object.hasOwn") \ 337 V(harmony_class_static_blocks, "harmony static initializer blocks") 338 339 #ifdef V8_INTL_SUPPORT 340 #define HARMONY_SHIPPING(V) \ 341 HARMONY_SHIPPING_BASE(V) \ 342 V(harmony_intl_dateformat_day_period, \ 343 "Add dayPeriod option to DateTimeFormat") \ 344 V(harmony_intl_displaynames_v2, "Intl.DisplayNames v2") \ 345 V(harmony_intl_more_timezone, \ 346 "Extend Intl.DateTimeFormat timeZoneName Option") 347 #else 348 #define HARMONY_SHIPPING(V) HARMONY_SHIPPING_BASE(V) 349 #endif 350 351 // Once a shipping feature has proved stable in the wild, it will be dropped 352 // from HARMONY_SHIPPING, all occurrences of the FLAG_ variable are removed, 353 // and associated tests are moved from the harmony directory to the appropriate 354 // esN directory. 355 356 #define FLAG_INPROGRESS_FEATURES(id, description) \ 357 DEFINE_BOOL(id, false, "enable " #description " (in progress)") 358 HARMONY_INPROGRESS(FLAG_INPROGRESS_FEATURES) 359 #undef FLAG_INPROGRESS_FEATURES 360 361 #define FLAG_STAGED_FEATURES(id, description) \ 362 DEFINE_BOOL(id, false, "enable " #description) \ 363 DEFINE_IMPLICATION(harmony, id) 364 HARMONY_STAGED(FLAG_STAGED_FEATURES) 365 #undef FLAG_STAGED_FEATURES 366 367 #define FLAG_SHIPPING_FEATURES(id, description) \ 368 DEFINE_BOOL(id, true, "enable " #description) \ 369 DEFINE_NEG_NEG_IMPLICATION(harmony_shipping, id) 370 HARMONY_SHIPPING(FLAG_SHIPPING_FEATURES) 371 #undef FLAG_SHIPPING_FEATURES 372 373 DEFINE_BOOL(builtin_subclassing, true, 374 "subclassing support in built-in methods") 375 376 // If the following flag is set to `true`, the SharedArrayBuffer constructor is 377 // enabled per context depending on the callback set via 378 // `SetSharedArrayBufferConstructorEnabledCallback`. If no callback is set, the 379 // SharedArrayBuffer constructor is disabled. 380 DEFINE_BOOL(enable_sharedarraybuffer_per_context, false, 381 "enable the SharedArrayBuffer constructor per context") 382 383 #ifdef V8_INTL_SUPPORT 384 DEFINE_BOOL(icu_timezone_data, true, "get information about timezones from ICU") 385 #endif 386 387 #ifdef V8_ENABLE_DOUBLE_CONST_STORE_CHECK 388 #define V8_ENABLE_DOUBLE_CONST_STORE_CHECK_BOOL true 389 #else 390 #define V8_ENABLE_DOUBLE_CONST_STORE_CHECK_BOOL false 391 #endif 392 393 #ifdef V8_LITE_MODE 394 #define V8_LITE_BOOL true 395 #else 396 #define V8_LITE_BOOL false 397 #endif 398 399 #ifdef V8_ENABLE_LAZY_SOURCE_POSITIONS 400 #define V8_LAZY_SOURCE_POSITIONS_BOOL true 401 #else 402 #define V8_LAZY_SOURCE_POSITIONS_BOOL false 403 #endif 404 405 #ifdef V8_SHARED_RO_HEAP 406 #define V8_SHARED_RO_HEAP_BOOL true 407 #else 408 #define V8_SHARED_RO_HEAP_BOOL false 409 #endif 410 411 DEFINE_BOOL(stress_snapshot, false, 412 "disables sharing of the read-only heap for testing") 413 // Incremental marking is incompatible with the stress_snapshot mode; 414 // specifically, serialization may clear bytecode arrays from shared function 415 // infos which the MarkCompactCollector (running concurrently) may still need. 416 // See also https://crbug.com/v8/10882. 417 // 418 // Note: This is not an issue in production because we don't clear SFI's 419 // there (that only happens in mksnapshot and in --stress-snapshot mode). 420 DEFINE_NEG_IMPLICATION(stress_snapshot, incremental_marking) 421 422 DEFINE_BOOL(lite_mode, V8_LITE_BOOL, 423 "enables trade-off of performance for memory savings") 424 425 // Lite mode implies other flags to trade-off performance for memory. 426 DEFINE_IMPLICATION(lite_mode, jitless) 427 DEFINE_IMPLICATION(lite_mode, lazy_feedback_allocation) 428 DEFINE_IMPLICATION(lite_mode, optimize_for_size) 429 430 #ifdef V8_ENABLE_THIRD_PARTY_HEAP 431 #define V8_ENABLE_THIRD_PARTY_HEAP_BOOL true 432 #else 433 #define V8_ENABLE_THIRD_PARTY_HEAP_BOOL false 434 #endif 435 436 DEFINE_NEG_IMPLICATION(enable_third_party_heap, inline_new) 437 DEFINE_NEG_IMPLICATION(enable_third_party_heap, allocation_site_pretenuring) 438 DEFINE_NEG_IMPLICATION(enable_third_party_heap, turbo_allocation_folding) 439 DEFINE_NEG_IMPLICATION(enable_third_party_heap, concurrent_recompilation) 440 DEFINE_NEG_IMPLICATION(enable_third_party_heap, concurrent_inlining) 441 DEFINE_NEG_IMPLICATION(enable_third_party_heap, 442 finalize_streaming_on_background) 443 DEFINE_NEG_IMPLICATION(enable_third_party_heap, use_marking_progress_bar) 444 DEFINE_NEG_IMPLICATION(enable_third_party_heap, move_object_start) 445 DEFINE_NEG_IMPLICATION(enable_third_party_heap, concurrent_marking) 446 447 DEFINE_BOOL_READONLY(enable_third_party_heap, V8_ENABLE_THIRD_PARTY_HEAP_BOOL, 448 "Use third-party heap") 449 450 #ifdef V8_ALLOCATION_FOLDING 451 #define V8_ALLOCATION_FOLDING_BOOL true 452 #else 453 #define V8_ALLOCATION_FOLDING_BOOL false 454 #endif 455 456 DEFINE_BOOL_READONLY(enable_allocation_folding, V8_ALLOCATION_FOLDING_BOOL, 457 "Use allocation folding globally") 458 DEFINE_NEG_NEG_IMPLICATION(enable_allocation_folding, turbo_allocation_folding) 459 460 #ifdef V8_DISABLE_WRITE_BARRIERS 461 #define V8_DISABLE_WRITE_BARRIERS_BOOL true 462 #else 463 #define V8_DISABLE_WRITE_BARRIERS_BOOL false 464 #endif 465 466 DEFINE_BOOL_READONLY(disable_write_barriers, V8_DISABLE_WRITE_BARRIERS_BOOL, 467 "disable write barriers when GC is non-incremental " 468 "and heap contains single generation.") 469 470 // Disable incremental marking barriers 471 DEFINE_NEG_IMPLICATION(disable_write_barriers, incremental_marking) 472 473 #ifdef V8_ENABLE_UNCONDITIONAL_WRITE_BARRIERS 474 #define V8_ENABLE_UNCONDITIONAL_WRITE_BARRIERS_BOOL true 475 #else 476 #define V8_ENABLE_UNCONDITIONAL_WRITE_BARRIERS_BOOL false 477 #endif 478 479 DEFINE_BOOL_READONLY(enable_unconditional_write_barriers, 480 V8_ENABLE_UNCONDITIONAL_WRITE_BARRIERS_BOOL, 481 "always use full write barriers") 482 483 #ifdef V8_ENABLE_SINGLE_GENERATION 484 #define V8_SINGLE_GENERATION_BOOL true 485 #else 486 #define V8_SINGLE_GENERATION_BOOL false 487 #endif 488 489 DEFINE_BOOL_READONLY( 490 single_generation, V8_SINGLE_GENERATION_BOOL, 491 "allocate all objects from young generation to old generation") 492 493 #ifdef V8_ENABLE_CONSERVATIVE_STACK_SCANNING 494 #define V8_ENABLE_CONSERVATIVE_STACK_SCANNING_BOOL true 495 #else 496 #define V8_ENABLE_CONSERVATIVE_STACK_SCANNING_BOOL false 497 #endif 498 DEFINE_BOOL_READONLY(conservative_stack_scanning, 499 V8_ENABLE_CONSERVATIVE_STACK_SCANNING_BOOL, 500 "use conservative stack scanning") 501 502 #ifdef V8_ENABLE_FUTURE 503 #define FUTURE_BOOL true 504 #else 505 #define FUTURE_BOOL false 506 #endif 507 DEFINE_BOOL(future, FUTURE_BOOL, 508 "Implies all staged features that we want to ship in the " 509 "not-too-far future") 510 511 #if ENABLE_SPARKPLUG 512 DEFINE_WEAK_IMPLICATION(future, sparkplug) 513 DEFINE_WEAK_IMPLICATION(future, flush_baseline_code) 514 #endif 515 #if V8_SHORT_BUILTIN_CALLS 516 DEFINE_WEAK_IMPLICATION(future, short_builtin_calls) 517 #endif 518 #if !MUST_WRITE_PROTECT_CODE_MEMORY 519 DEFINE_WEAK_VALUE_IMPLICATION(future, write_protect_code_memory, false) 520 #endif 521 522 // Flags for jitless 523 DEFINE_BOOL(jitless, V8_LITE_BOOL, 524 "Disable runtime allocation of executable memory.") 525 526 // Jitless V8 has a few implications: 527 DEFINE_NEG_IMPLICATION(jitless, opt) 528 // Field type tracking is only used by TurboFan. 529 DEFINE_NEG_IMPLICATION(jitless, track_field_types) 530 // Regexps are interpreted. 531 DEFINE_IMPLICATION(jitless, regexp_interpret_all) 532 #if ENABLE_SPARKPLUG 533 // No Sparkplug compilation. 534 DEFINE_NEG_IMPLICATION(jitless, sparkplug) 535 DEFINE_NEG_IMPLICATION(jitless, always_sparkplug) 536 #endif 537 538 #ifndef V8_TARGET_ARCH_ARM 539 // Unsupported on arm. See https://crbug.com/v8/8713. 540 DEFINE_NEG_IMPLICATION(jitless, interpreted_frames_native_stack) 541 #endif 542 543 DEFINE_BOOL(assert_types, false, 544 "generate runtime type assertions to test the typer") 545 546 DEFINE_BOOL(trace_compilation_dependencies, false, "trace code dependencies") 547 // Depend on --trace-deopt-verbose for reporting dependency invalidations. 548 DEFINE_IMPLICATION(trace_compilation_dependencies, trace_deopt_verbose) 549 550 #ifdef V8_ALLOCATION_SITE_TRACKING 551 #define V8_ALLOCATION_SITE_TRACKING_BOOL true 552 #else 553 #define V8_ALLOCATION_SITE_TRACKING_BOOL false 554 #endif 555 556 DEFINE_BOOL_READONLY(allocation_site_tracking, V8_ALLOCATION_SITE_TRACKING_BOOL, 557 "Enable allocation site tracking") 558 DEFINE_NEG_NEG_IMPLICATION(allocation_site_tracking, 559 allocation_site_pretenuring) 560 561 // Flags for experimental implementation features. 562 DEFINE_BOOL(allocation_site_pretenuring, true, 563 "pretenure with allocation sites") 564 DEFINE_BOOL(page_promotion, true, "promote pages based on utilization") 565 DEFINE_BOOL_READONLY(always_promote_young_mc, true, 566 "always promote young objects during mark-compact") 567 DEFINE_INT(page_promotion_threshold, 70, 568 "min percentage of live bytes on a page to enable fast evacuation") 569 DEFINE_BOOL(trace_pretenuring, false, 570 "trace pretenuring decisions of HAllocate instructions") 571 DEFINE_BOOL(trace_pretenuring_statistics, false, 572 "trace allocation site pretenuring statistics") 573 DEFINE_BOOL(track_field_types, true, "track field types") 574 DEFINE_BOOL(trace_block_coverage, false, 575 "trace collected block coverage information") 576 DEFINE_BOOL(trace_protector_invalidation, false, 577 "trace protector cell invalidations") 578 DEFINE_BOOL(trace_web_snapshot, false, "trace web snapshot deserialization") 579 580 DEFINE_BOOL(feedback_normalization, false, 581 "feed back normalization to constructors") 582 // TODO(jkummerow): This currently adds too much load on the stub cache. 583 DEFINE_BOOL_READONLY(internalize_on_the_fly, true, 584 "internalize string keys for generic keyed ICs on the fly") 585 586 // Flag for sealed, frozen elements kind instead of dictionary elements kind 587 DEFINE_BOOL_READONLY(enable_sealed_frozen_elements_kind, true, 588 "Enable sealed, frozen elements kind") 589 590 // Flags for data representation optimizations 591 DEFINE_BOOL(unbox_double_arrays, true, "automatically unbox arrays of doubles") 592 DEFINE_BOOL_READONLY(string_slices, true, "use string slices") 593 594 DEFINE_INT(ticks_before_optimization, 3, 595 "the number of times we have to go through the interrupt budget " 596 "before considering this function for optimization") 597 DEFINE_INT(bytecode_size_allowance_per_tick, 1100, 598 "increases the number of ticks required for optimization by " 599 "bytecode.length/X") 600 DEFINE_INT(interrupt_budget, 132 * KB, 601 "interrupt budget which should be used for the profiler counter") 602 DEFINE_INT( 603 max_bytecode_size_for_early_opt, 81, 604 "Maximum bytecode length for a function to be optimized on the first tick") 605 606 // Flags for inline caching and feedback vectors. 607 DEFINE_BOOL(use_ic, true, "use inline caching") 608 DEFINE_INT(budget_for_feedback_vector_allocation, 940, 609 "The budget in amount of bytecode executed by a function before we " 610 "decide to allocate feedback vectors") 611 DEFINE_INT(scale_factor_for_feedback_allocation, 8, 612 "scale bytecode size for feedback vector allocation.") 613 DEFINE_BOOL(feedback_allocation_on_bytecode_size, true, 614 "Instead of a fixed budget for lazy feedback vector allocation, " 615 "scale it based in the bytecode size.") 616 DEFINE_IMPLICATION(sparkplug, feedback_allocation_on_bytecode_size) 617 DEFINE_BOOL(lazy_feedback_allocation, true, "Allocate feedback vectors lazily") 618 619 // Flags for Ignition. 620 DEFINE_BOOL(ignition_elide_noneffectful_bytecodes, true, 621 "elide bytecodes which won't have any external effect") 622 DEFINE_BOOL(ignition_reo, true, "use ignition register equivalence optimizer") 623 DEFINE_BOOL(ignition_filter_expression_positions, true, 624 "filter expression positions before the bytecode pipeline") 625 DEFINE_BOOL(ignition_share_named_property_feedback, true, 626 "share feedback slots when loading the same named property from " 627 "the same object") 628 DEFINE_BOOL(print_bytecode, false, 629 "print bytecode generated by ignition interpreter") 630 DEFINE_BOOL(enable_lazy_source_positions, V8_LAZY_SOURCE_POSITIONS_BOOL, 631 "skip generating source positions during initial compile but " 632 "regenerate when actually required") 633 DEFINE_BOOL(stress_lazy_source_positions, false, 634 "collect lazy source positions immediately after lazy compile") 635 DEFINE_STRING(print_bytecode_filter, "*", 636 "filter for selecting which functions to print bytecode") 637 #ifdef V8_TRACE_UNOPTIMIZED 638 DEFINE_BOOL(trace_unoptimized, false, 639 "trace the bytecodes executed by all unoptimized execution") 640 DEFINE_BOOL(trace_ignition, false, 641 "trace the bytecodes executed by the ignition interpreter") 642 DEFINE_BOOL(trace_baseline_exec, false, 643 "trace the bytecodes executed by the baseline code") 644 DEFINE_WEAK_IMPLICATION(trace_unoptimized, trace_ignition) 645 DEFINE_WEAK_IMPLICATION(trace_unoptimized, trace_baseline_exec) 646 #endif 647 #ifdef V8_TRACE_FEEDBACK_UPDATES 648 DEFINE_BOOL( 649 trace_feedback_updates, false, 650 "trace updates to feedback vectors during ignition interpreter execution.") 651 #endif 652 DEFINE_BOOL(trace_ignition_codegen, false, 653 "trace the codegen of ignition interpreter bytecode handlers") 654 DEFINE_STRING( 655 trace_ignition_dispatches_output_file, nullptr, 656 "write the bytecode handler dispatch table to the specified file (d8 only) " 657 "(requires building with v8_enable_ignition_dispatch_counting)") 658 659 DEFINE_BOOL(trace_track_allocation_sites, false, 660 "trace the tracking of allocation sites") 661 DEFINE_BOOL(trace_migration, false, "trace object migration") 662 DEFINE_BOOL(trace_generalization, false, "trace map generalization") 663 664 // Flags for TurboProp. 665 DEFINE_BOOL(turboprop, false, "enable experimental turboprop mid-tier compiler") 666 DEFINE_BOOL(turboprop_mid_tier_reg_alloc, true, 667 "enable mid-tier register allocator for turboprop") 668 DEFINE_BOOL( 669 turboprop_as_toptier, false, 670 "enable experimental turboprop compiler without further tierup to turbofan") 671 DEFINE_IMPLICATION(turboprop_as_toptier, turboprop) 672 DEFINE_WEAK_VALUE_IMPLICATION(turboprop, interrupt_budget, 115 * KB) 673 DEFINE_UINT_READONLY(max_minimorphic_map_checks, 4, 674 "max number of map checks to perform in minimorphic state") 675 DEFINE_INT(turboprop_inline_scaling_factor, 4, 676 "scale factor for reduction in bytecode that can be inline for " 677 "TurboProp compared to TurboFan") 678 // The scale factor determines the interrupt budget when tiering up from 679 // Turboprop to TurboFan. 680 DEFINE_INT(interrupt_budget_scale_factor_for_top_tier, 20, 681 "scale factor for profiler ticks when tiering up from midtier") 682 683 // Flags for Sparkplug 684 #undef FLAG 685 #if ENABLE_SPARKPLUG 686 #define FLAG FLAG_FULL 687 #else 688 #define FLAG FLAG_READONLY 689 #endif 690 DEFINE_BOOL(sparkplug, ENABLE_SPARKPLUG_BY_DEFAULT, 691 "enable Sparkplug baseline compiler") 692 DEFINE_BOOL(always_sparkplug, false, "directly tier up to Sparkplug code") 693 DEFINE_BOOL(sparkplug_on_heap, false, "compile Sparkplug code directly on heap") 694 #if ENABLE_SPARKPLUG 695 DEFINE_IMPLICATION(always_sparkplug, sparkplug) 696 DEFINE_BOOL(baseline_batch_compilation, true, "batch compile Sparkplug code") 697 #else 698 DEFINE_BOOL(baseline_batch_compilation, false, "batch compile Sparkplug code") 699 #endif 700 DEFINE_STRING(sparkplug_filter, "*", "filter for Sparkplug baseline compiler") 701 DEFINE_BOOL(sparkplug_needs_short_builtins, false, 702 "only enable Sparkplug baseline compiler when " 703 "--short-builtin-calls are also enabled") 704 DEFINE_INT(baseline_batch_compilation_threshold, 4 * KB, 705 "the estimated instruction size of a batch to trigger compilation") 706 DEFINE_BOOL(trace_baseline, false, "trace baseline compilation") 707 DEFINE_BOOL(trace_baseline_batch_compilation, false, 708 "trace baseline batch compilation") 709 710 #undef FLAG 711 #define FLAG FLAG_FULL 712 713 #if !defined(V8_OS_MACOSX) || !defined(V8_HOST_ARCH_ARM64) 714 DEFINE_BOOL(write_code_using_rwx, true, 715 "flip permissions to rwx to write page instead of rw") 716 DEFINE_NEG_IMPLICATION(jitless, write_code_using_rwx) 717 #else 718 DEFINE_BOOL_READONLY(write_code_using_rwx, false, 719 "flip permissions to rwx to write page instead of rw") 720 #endif 721 722 // Flags for concurrent recompilation. 723 DEFINE_BOOL(concurrent_recompilation, true, 724 "optimizing hot functions asynchronously on a separate thread") 725 DEFINE_BOOL(trace_concurrent_recompilation, false, 726 "track concurrent recompilation") 727 DEFINE_INT(concurrent_recompilation_queue_length, 8, 728 "the length of the concurrent compilation queue") 729 DEFINE_INT(concurrent_recompilation_delay, 0, 730 "artificial compilation delay in ms") 731 DEFINE_BOOL(concurrent_inlining, true, 732 "run optimizing compiler's inlining phase on a separate thread") 733 DEFINE_BOOL( 734 stress_concurrent_inlining, false, 735 "create additional concurrent optimization jobs but throw away result") 736 DEFINE_IMPLICATION(stress_concurrent_inlining, concurrent_inlining) 737 DEFINE_NEG_IMPLICATION(stress_concurrent_inlining, lazy_feedback_allocation) 738 DEFINE_WEAK_VALUE_IMPLICATION(stress_concurrent_inlining, interrupt_budget, 739 15 * KB) 740 DEFINE_BOOL(stress_concurrent_inlining_attach_code, false, 741 "create additional concurrent optimization jobs") 742 DEFINE_IMPLICATION(stress_concurrent_inlining_attach_code, 743 stress_concurrent_inlining) 744 DEFINE_INT(max_serializer_nesting, 25, 745 "maximum levels for nesting child serializers") 746 DEFINE_BOOL(trace_heap_broker_verbose, false, 747 "trace the heap broker verbosely (all reports)") 748 DEFINE_BOOL(trace_heap_broker_memory, false, 749 "trace the heap broker memory (refs analysis and zone numbers)") 750 DEFINE_BOOL(trace_heap_broker, false, 751 "trace the heap broker (reports on missing data only)") 752 DEFINE_IMPLICATION(trace_heap_broker_verbose, trace_heap_broker) 753 DEFINE_IMPLICATION(trace_heap_broker_memory, trace_heap_broker) 754 DEFINE_IMPLICATION(trace_heap_broker, trace_pending_allocations) 755 756 // Flags for stress-testing the compiler. 757 DEFINE_INT(stress_runs, 0, "number of stress runs") 758 DEFINE_INT(deopt_every_n_times, 0, 759 "deoptimize every n times a deopt point is passed") 760 DEFINE_BOOL(print_deopt_stress, false, "print number of possible deopt points") 761 762 // Flags for TurboFan. 763 DEFINE_BOOL(opt, true, "use adaptive optimizations") 764 DEFINE_BOOL(turbo_sp_frame_access, false, 765 "use stack pointer-relative access to frame wherever possible") 766 DEFINE_BOOL( 767 stress_turbo_late_spilling, false, 768 "optimize placement of all spill instructions, not just loop-top phis") 769 770 DEFINE_STRING(turbo_filter, "*", "optimization filter for TurboFan compiler") 771 DEFINE_BOOL(trace_turbo, false, "trace generated TurboFan IR") 772 DEFINE_STRING(trace_turbo_path, nullptr, 773 "directory to dump generated TurboFan IR to") 774 DEFINE_STRING(trace_turbo_filter, "*", 775 "filter for tracing turbofan compilation") 776 DEFINE_BOOL(trace_turbo_graph, false, "trace generated TurboFan graphs") 777 DEFINE_BOOL(trace_turbo_scheduled, false, "trace TurboFan IR with schedule") 778 DEFINE_IMPLICATION(trace_turbo_scheduled, trace_turbo_graph) 779 DEFINE_STRING(trace_turbo_cfg_file, nullptr, 780 "trace turbo cfg graph (for C1 visualizer) to a given file name") 781 DEFINE_BOOL(trace_turbo_types, true, "trace TurboFan's types") 782 DEFINE_BOOL(trace_turbo_scheduler, false, "trace TurboFan's scheduler") 783 DEFINE_BOOL(trace_turbo_reduction, false, "trace TurboFan's various reducers") 784 DEFINE_BOOL(trace_turbo_trimming, false, "trace TurboFan's graph trimmer") 785 DEFINE_BOOL(trace_turbo_jt, false, "trace TurboFan's jump threading") 786 DEFINE_BOOL(trace_turbo_ceq, false, "trace TurboFan's control equivalence") 787 DEFINE_BOOL(trace_turbo_loop, false, "trace TurboFan's loop optimizations") 788 DEFINE_BOOL(trace_turbo_alloc, false, "trace TurboFan's register allocator") 789 DEFINE_BOOL(trace_all_uses, false, "trace all use positions") 790 DEFINE_BOOL(trace_representation, false, "trace representation types") 791 DEFINE_BOOL( 792 trace_turbo_stack_accesses, false, 793 "trace stack load/store counters for optimized code in run-time (x64 only)") 794 DEFINE_BOOL(turbo_verify, DEBUG_BOOL, "verify TurboFan graphs at each phase") 795 DEFINE_STRING(turbo_verify_machine_graph, nullptr, 796 "verify TurboFan machine graph before instruction selection") 797 #ifdef ENABLE_VERIFY_CSA 798 DEFINE_BOOL(verify_csa, DEBUG_BOOL, 799 "verify TurboFan machine graph of code stubs") 800 #else 801 // Define the flag as read-only-false so that code still compiles even in the 802 // non-ENABLE_VERIFY_CSA configuration. 803 DEFINE_BOOL_READONLY(verify_csa, false, 804 "verify TurboFan machine graph of code stubs") 805 #endif 806 DEFINE_BOOL(trace_verify_csa, false, "trace code stubs verification") 807 DEFINE_STRING(csa_trap_on_node, nullptr, 808 "trigger break point when a node with given id is created in " 809 "given stub. The format is: StubName,NodeId") 810 DEFINE_BOOL_READONLY(fixed_array_bounds_checks, true, 811 "enable FixedArray bounds checks") 812 DEFINE_BOOL(turbo_stats, false, "print TurboFan statistics") 813 DEFINE_BOOL(turbo_stats_nvp, false, 814 "print TurboFan statistics in machine-readable format") 815 DEFINE_BOOL(turbo_stats_wasm, false, 816 "print TurboFan statistics of wasm compilations") 817 DEFINE_BOOL(turbo_splitting, true, "split nodes during scheduling in TurboFan") 818 DEFINE_BOOL(function_context_specialization, false, 819 "enable function context specialization in TurboFan") 820 DEFINE_BOOL(turbo_inlining, true, "enable inlining in TurboFan") 821 DEFINE_INT(max_inlined_bytecode_size, 460, 822 "maximum size of bytecode for a single inlining") 823 DEFINE_INT(max_inlined_bytecode_size_cumulative, 920, 824 "maximum cumulative size of bytecode considered for inlining") 825 DEFINE_INT(max_inlined_bytecode_size_absolute, 4600, 826 "maximum absolute size of bytecode considered for inlining") 827 DEFINE_FLOAT( 828 reserve_inline_budget_scale_factor, 1.2, 829 "scale factor of bytecode size used to calculate the inlining budget") 830 DEFINE_INT(max_inlined_bytecode_size_small, 27, 831 "maximum size of bytecode considered for small function inlining") 832 DEFINE_INT(max_optimized_bytecode_size, 60 * KB, 833 "maximum bytecode size to " 834 "be considered for optimization; too high values may cause " 835 "the compiler to hit (release) assertions") 836 DEFINE_FLOAT(min_inlining_frequency, 0.15, "minimum frequency for inlining") 837 DEFINE_BOOL(polymorphic_inlining, true, "polymorphic inlining") 838 DEFINE_BOOL(stress_inline, false, 839 "set high thresholds for inlining to inline as much as possible") 840 DEFINE_VALUE_IMPLICATION(stress_inline, max_inlined_bytecode_size, 999999) 841 DEFINE_VALUE_IMPLICATION(stress_inline, max_inlined_bytecode_size_cumulative, 842 999999) 843 DEFINE_VALUE_IMPLICATION(stress_inline, max_inlined_bytecode_size_absolute, 844 999999) 845 DEFINE_VALUE_IMPLICATION(stress_inline, min_inlining_frequency, 0) 846 DEFINE_IMPLICATION(stress_inline, polymorphic_inlining) 847 DEFINE_BOOL(trace_turbo_inlining, false, "trace TurboFan inlining") 848 DEFINE_BOOL(turbo_inline_array_builtins, true, 849 "inline array builtins in TurboFan code") 850 DEFINE_BOOL(use_osr, true, "use on-stack replacement") 851 DEFINE_BOOL(trace_osr, false, "trace on-stack replacement") 852 DEFINE_BOOL(analyze_environment_liveness, true, 853 "analyze liveness of environment slots and zap dead values") 854 DEFINE_BOOL(trace_environment_liveness, false, 855 "trace liveness of local variable slots") 856 DEFINE_BOOL(turbo_load_elimination, true, "enable load elimination in TurboFan") 857 DEFINE_BOOL(trace_turbo_load_elimination, false, 858 "trace TurboFan load elimination") 859 DEFINE_BOOL(turbo_profiling, false, "enable basic block profiling in TurboFan") 860 DEFINE_BOOL(turbo_profiling_verbose, false, 861 "enable basic block profiling in TurboFan, and include each " 862 "function's schedule and disassembly in the output") 863 DEFINE_IMPLICATION(turbo_profiling_verbose, turbo_profiling) 864 DEFINE_BOOL(turbo_profiling_log_builtins, false, 865 "emit data about basic block usage in builtins to v8.log (requires " 866 "that V8 was built with v8_enable_builtins_profiling=true)") 867 DEFINE_BOOL(turbo_verify_allocation, DEBUG_BOOL, 868 "verify register allocation in TurboFan") 869 DEFINE_BOOL(turbo_move_optimization, true, "optimize gap moves in TurboFan") 870 DEFINE_BOOL(turbo_jt, true, "enable jump threading in TurboFan") 871 DEFINE_BOOL(turbo_loop_peeling, true, "TurboFan loop peeling") 872 DEFINE_BOOL(turbo_loop_variable, true, "TurboFan loop variable optimization") 873 DEFINE_BOOL(turbo_loop_rotation, true, "TurboFan loop rotation") 874 DEFINE_BOOL(turbo_cf_optimization, true, "optimize control flow in TurboFan") 875 DEFINE_BOOL(turbo_escape, true, "enable escape analysis") 876 DEFINE_BOOL(turbo_allocation_folding, true, "TurboFan allocation folding") 877 DEFINE_BOOL(turbo_instruction_scheduling, false, 878 "enable instruction scheduling in TurboFan") 879 DEFINE_BOOL(turbo_stress_instruction_scheduling, false, 880 "randomly schedule instructions to stress dependency tracking") 881 DEFINE_IMPLICATION(turbo_stress_instruction_scheduling, 882 turbo_instruction_scheduling) 883 DEFINE_BOOL(turbo_store_elimination, true, 884 "enable store-store elimination in TurboFan") 885 DEFINE_BOOL(trace_store_elimination, false, "trace store elimination") 886 DEFINE_BOOL(turbo_rewrite_far_jumps, true, 887 "rewrite far to near jumps (ia32,x64)") 888 DEFINE_BOOL( 889 stress_gc_during_compilation, false, 890 "simulate GC/compiler thread race related to https://crbug.com/v8/8520") 891 DEFINE_BOOL(turbo_fast_api_calls, false, "enable fast API calls from TurboFan") 892 DEFINE_INT(reuse_opt_code_count, 0, 893 "don't discard optimized code for the specified number of deopts.") 894 DEFINE_BOOL(turbo_dynamic_map_checks, false, 895 "use dynamic map checks when generating code for property accesses " 896 "if all handlers in an IC are the same for turboprop") 897 DEFINE_BOOL(turbo_compress_translation_arrays, false, 898 "compress translation arrays (experimental)") 899 DEFINE_BOOL(turbo_inline_js_wasm_calls, true, "inline JS->Wasm calls") 900 901 DEFINE_BOOL(turbo_optimize_apply, true, "optimize Function.prototype.apply") 902 903 DEFINE_BOOL(turbo_collect_feedback_in_generic_lowering, true, 904 "enable experimental feedback collection in generic lowering.") 905 DEFINE_BOOL(isolate_script_cache_ageing, true, 906 "enable ageing of the isolate script cache.") 907 908 DEFINE_FLOAT(script_delay, 0, "busy wait [ms] on every Script::Run") 909 DEFINE_FLOAT(script_delay_once, 0, "busy wait [ms] on the first Script::Run") 910 DEFINE_FLOAT(script_delay_fraction, 0.0, 911 "busy wait after each Script::Run by the given fraction of the " 912 "run's duration") 913 914 // Favor memory over execution speed. 915 DEFINE_BOOL(optimize_for_size, false, 916 "Enables optimizations which favor memory size over execution " 917 "speed") 918 DEFINE_VALUE_IMPLICATION(optimize_for_size, max_semi_space_size, 1) 919 920 // Flags for WebAssembly. 921 #if V8_ENABLE_WEBASSEMBLY 922 923 DEFINE_BOOL(wasm_generic_wrapper, true, 924 "allow use of the generic js-to-wasm wrapper instead of " 925 "per-signature wrappers") 926 DEFINE_BOOL(expose_wasm, true, "expose wasm interface to JavaScript") 927 DEFINE_INT(wasm_num_compilation_tasks, 128, 928 "maximum number of parallel compilation tasks for wasm") 929 DEFINE_VALUE_IMPLICATION(single_threaded, wasm_num_compilation_tasks, 0) 930 DEFINE_DEBUG_BOOL(trace_wasm_native_heap, false, 931 "trace wasm native heap events") 932 DEFINE_BOOL(wasm_write_protect_code_memory, false, 933 "write protect code memory on the wasm native heap with mprotect") 934 DEFINE_WEAK_IMPLICATION(future, wasm_write_protect_code_memory) 935 DEFINE_BOOL(wasm_memory_protection_keys, false, 936 "protect wasm code memory with PKU if available, no protection " 937 "without support; fallback to mprotect by adding " 938 "--wasm-write-protect-code-memory") 939 DEFINE_WEAK_IMPLICATION(future, wasm_memory_protection_keys) 940 DEFINE_DEBUG_BOOL(trace_wasm_serialization, false, 941 "trace serialization/deserialization") 942 DEFINE_BOOL(wasm_async_compilation, true, 943 "enable actual asynchronous compilation for WebAssembly.compile") 944 DEFINE_NEG_IMPLICATION(single_threaded, wasm_async_compilation) 945 DEFINE_BOOL(wasm_test_streaming, false, 946 "use streaming compilation instead of async compilation for tests") 947 DEFINE_UINT(wasm_max_mem_pages, v8::internal::wasm::kV8MaxWasmMemoryPages, 948 "maximum number of 64KiB memory pages per wasm memory") 949 DEFINE_UINT(wasm_max_table_size, v8::internal::wasm::kV8MaxWasmTableSize, 950 "maximum table size of a wasm instance") 951 DEFINE_UINT(wasm_max_code_space, v8::internal::kMaxWasmCodeMB, 952 "maximum committed code space for wasm (in MB)") 953 DEFINE_BOOL(wasm_tier_up, true, 954 "enable tier up to the optimizing compiler (requires --liftoff to " 955 "have an effect)") 956 DEFINE_BOOL(wasm_dynamic_tiering, false, 957 "enable dynamic tier up to the optimizing compiler") 958 DEFINE_INT( 959 wasm_caching_threshold, 1000000, 960 "the amount of wasm top tier code that triggers the next caching event") 961 DEFINE_DEBUG_BOOL(trace_wasm_decoder, false, "trace decoding of wasm code") 962 DEFINE_DEBUG_BOOL(trace_wasm_compiler, false, "trace compiling of wasm code") 963 DEFINE_DEBUG_BOOL(trace_wasm_interpreter, false, 964 "trace interpretation of wasm code") 965 DEFINE_DEBUG_BOOL(trace_wasm_streaming, false, 966 "trace streaming compilation of wasm code") 967 DEFINE_BOOL(liftoff, true, 968 "enable Liftoff, the baseline compiler for WebAssembly") 969 DEFINE_BOOL(liftoff_only, false, 970 "disallow TurboFan compilation for WebAssembly (for testing)") 971 DEFINE_IMPLICATION(liftoff_only, liftoff) 972 DEFINE_NEG_IMPLICATION(liftoff_only, wasm_tier_up) 973 DEFINE_NEG_IMPLICATION(fuzzing, liftoff_only) 974 DEFINE_DEBUG_BOOL( 975 enable_testing_opcode_in_wasm, false, 976 "enables a testing opcode in wasm that is only implemented in TurboFan") 977 // We can't tier up (from Liftoff to TurboFan) in single-threaded mode, hence 978 // disable tier up in that configuration for now. 979 DEFINE_NEG_IMPLICATION(single_threaded, wasm_tier_up) 980 DEFINE_DEBUG_BOOL(trace_liftoff, false, 981 "trace Liftoff, the baseline compiler for WebAssembly") 982 DEFINE_BOOL(trace_wasm_memory, false, 983 "print all memory updates performed in wasm code") 984 // Fuzzers use {wasm_tier_mask_for_testing} and {wasm_debug_mask_for_testing} 985 // together with {liftoff} and {no_wasm_tier_up} to force some functions to be 986 // compiled with TurboFan or for debug. 987 DEFINE_INT(wasm_tier_mask_for_testing, 0, 988 "bitmask of functions to compile with TurboFan instead of Liftoff") 989 DEFINE_INT(wasm_debug_mask_for_testing, 0, 990 "bitmask of functions to compile for debugging, only applies if the " 991 "tier is Liftoff") 992 993 DEFINE_BOOL(validate_asm, true, "validate asm.js modules before compiling") 994 // asm.js validation is disabled since it triggers wasm code generation. 995 // --jitless also implies --no-expose-wasm, see InitializeOncePerProcessImpl. 996 DEFINE_NEG_IMPLICATION(jitless, validate_asm) 997 DEFINE_BOOL(suppress_asm_messages, false, 998 "don't emit asm.js related messages (for golden file testing)") 999 DEFINE_BOOL(trace_asm_time, false, "print asm.js timing info to the console") 1000 DEFINE_BOOL(trace_asm_scanner, false, 1001 "print tokens encountered by asm.js scanner") 1002 DEFINE_BOOL(trace_asm_parser, false, "verbose logging of asm.js parse failures") 1003 DEFINE_BOOL(stress_validate_asm, false, "try to validate everything as asm.js") 1004 1005 DEFINE_DEBUG_BOOL(dump_wasm_module, false, "dump wasm module bytes") 1006 DEFINE_STRING(dump_wasm_module_path, nullptr, 1007 "directory to dump wasm modules to") 1008 1009 // Declare command-line flags for Wasm features. Warning: avoid using these 1010 // flags directly in the implementation. Instead accept wasm::WasmFeatures 1011 // for configurability. 1012 #include "src/wasm/wasm-feature-flags.h" 1013 1014 #define DECL_WASM_FLAG(feat, desc, val) \ 1015 DEFINE_BOOL(experimental_wasm_##feat, val, \ 1016 "enable prototype " desc " for wasm") 1017 FOREACH_WASM_FEATURE_FLAG(DECL_WASM_FLAG) 1018 #undef DECL_WASM_FLAG 1019 1020 DEFINE_IMPLICATION(experimental_wasm_gc, experimental_wasm_typed_funcref) 1021 DEFINE_IMPLICATION(experimental_wasm_typed_funcref, experimental_wasm_reftypes) 1022 1023 DEFINE_BOOL(wasm_gc_js_interop, false, "experimental WasmGC-JS interop") 1024 1025 DEFINE_BOOL(wasm_staging, false, "enable staged wasm features") 1026 1027 #define WASM_STAGING_IMPLICATION(feat, desc, val) \ 1028 DEFINE_IMPLICATION(wasm_staging, experimental_wasm_##feat) 1029 FOREACH_WASM_STAGING_FEATURE_FLAG(WASM_STAGING_IMPLICATION) 1030 #undef WASM_STAGING_IMPLICATION 1031 1032 DEFINE_BOOL(wasm_opt, true, "enable wasm optimization") 1033 DEFINE_BOOL( 1034 wasm_bounds_checks, true, 1035 "enable bounds checks (disable for performance testing only)") 1036 DEFINE_BOOL(wasm_stack_checks, true, 1037 "enable stack checks (disable for performance testing only)") 1038 DEFINE_BOOL( 1039 wasm_enforce_bounds_checks, false, 1040 "enforce explicit bounds check even if the trap handler is available") 1041 // "no bounds checks" implies "no enforced bounds checks". 1042 DEFINE_NEG_NEG_IMPLICATION(wasm_bounds_checks, wasm_enforce_bounds_checks) 1043 DEFINE_BOOL(wasm_math_intrinsics, true, 1044 "intrinsify some Math imports into wasm") 1045 1046 DEFINE_BOOL( 1047 wasm_inlining, false, 1048 "enable inlining of wasm functions into wasm functions (experimental)") 1049 DEFINE_BOOL(wasm_loop_unrolling, true, 1050 "enable loop unrolling for wasm functions") 1051 DEFINE_BOOL(wasm_fuzzer_gen_test, false, 1052 "generate a test case when running a wasm fuzzer") 1053 DEFINE_IMPLICATION(wasm_fuzzer_gen_test, single_threaded) 1054 DEFINE_BOOL(print_wasm_code, false, "print WebAssembly code") 1055 DEFINE_INT(print_wasm_code_function_index, -1, 1056 "print WebAssembly code for function at index") 1057 DEFINE_BOOL(print_wasm_stub_code, false, "print WebAssembly stub code") 1058 DEFINE_BOOL(asm_wasm_lazy_compilation, false, 1059 "enable lazy compilation for asm-wasm modules") 1060 DEFINE_IMPLICATION(validate_asm, asm_wasm_lazy_compilation) 1061 DEFINE_BOOL(wasm_lazy_compilation, false, 1062 "enable lazy compilation for all wasm modules") 1063 DEFINE_DEBUG_BOOL(trace_wasm_lazy_compilation, false, 1064 "trace lazy compilation of wasm functions") 1065 DEFINE_BOOL(wasm_lazy_validation, false, 1066 "enable lazy validation for lazily compiled wasm functions") 1067 DEFINE_BOOL(wasm_simd_ssse3_codegen, false, "allow wasm SIMD SSSE3 codegen") 1068 1069 DEFINE_BOOL(wasm_code_gc, true, "enable garbage collection of wasm code") 1070 DEFINE_BOOL(trace_wasm_code_gc, false, "trace garbage collection of wasm code") 1071 DEFINE_BOOL(stress_wasm_code_gc, false, 1072 "stress test garbage collection of wasm code") 1073 DEFINE_INT(wasm_max_initial_code_space_reservation, 0, 1074 "maximum size of the initial wasm code space reservation (in MB)") 1075 1076 DEFINE_BOOL(experimental_wasm_allow_huge_modules, false, 1077 "allow wasm modules bigger than 1GB, but below ~2GB") 1078 1079 DEFINE_BOOL(trace_wasm, false, "trace wasm function calls") 1080 1081 // Flags for Wasm GDB remote debugging. 1082 #ifdef V8_ENABLE_WASM_GDB_REMOTE_DEBUGGING 1083 #define DEFAULT_WASM_GDB_REMOTE_PORT 8765 1084 DEFINE_BOOL(wasm_gdb_remote, false, 1085 "enable GDB-remote for WebAssembly debugging") 1086 DEFINE_NEG_IMPLICATION(wasm_gdb_remote, wasm_tier_up) 1087 DEFINE_INT(wasm_gdb_remote_port, DEFAULT_WASM_GDB_REMOTE_PORT, 1088 "default port for WebAssembly debugging with LLDB.") 1089 DEFINE_BOOL(wasm_pause_waiting_for_debugger, false, 1090 "pause at the first Webassembly instruction waiting for a debugger " 1091 "to attach") 1092 DEFINE_BOOL(trace_wasm_gdb_remote, false, "trace Webassembly GDB-remote server") 1093 #endif // V8_ENABLE_WASM_GDB_REMOTE_DEBUGGING 1094 1095 // wasm instance management 1096 DEFINE_DEBUG_BOOL(trace_wasm_instances, false, 1097 "trace creation and collection of wasm instances") 1098 1099 #endif // V8_ENABLE_WEBASSEMBLY 1100 1101 DEFINE_INT(stress_sampling_allocation_profiler, 0, 1102 "Enables sampling allocation profiler with X as a sample interval") 1103 1104 // Garbage collections flags. 1105 DEFINE_BOOL(lazy_new_space_shrinking, false, 1106 "Enables the lazy new space shrinking strategy") 1107 DEFINE_SIZE_T(min_semi_space_size, 0, 1108 "min size of a semi-space (in MBytes), the new space consists of " 1109 "two semi-spaces") 1110 DEFINE_SIZE_T(max_semi_space_size, 0, 1111 "max size of a semi-space (in MBytes), the new space consists of " 1112 "two semi-spaces") 1113 DEFINE_INT(semi_space_growth_factor, 2, "factor by which to grow the new space") 1114 DEFINE_SIZE_T(max_old_space_size, 0, "max size of the old space (in Mbytes)") 1115 DEFINE_SIZE_T( 1116 max_heap_size, 0, 1117 "max size of the heap (in Mbytes) " 1118 "both max_semi_space_size and max_old_space_size take precedence. " 1119 "All three flags cannot be specified at the same time.") 1120 DEFINE_SIZE_T(initial_heap_size, 0, "initial size of the heap (in Mbytes)") 1121 DEFINE_BOOL(huge_max_old_generation_size, true, 1122 "Increase max size of the old space to 4 GB for x64 systems with" 1123 "the physical memory bigger than 16 GB") 1124 DEFINE_SIZE_T(initial_old_space_size, 0, "initial old space size (in Mbytes)") 1125 DEFINE_BOOL(global_gc_scheduling, true, 1126 "enable GC scheduling based on global memory") 1127 DEFINE_BOOL(gc_global, false, "always perform global GCs") 1128 DEFINE_INT(random_gc_interval, 0, 1129 "Collect garbage after random(0, X) allocations. It overrides " 1130 "gc_interval.") 1131 DEFINE_INT(gc_interval, -1, "garbage collect after <n> allocations") 1132 DEFINE_INT(retain_maps_for_n_gc, 2, 1133 "keeps maps alive for <n> old space garbage collections") 1134 DEFINE_BOOL(trace_gc, false, 1135 "print one trace line following each garbage collection") 1136 DEFINE_BOOL(trace_gc_nvp, false, 1137 "print one detailed trace line in name=value format " 1138 "after each garbage collection") 1139 DEFINE_BOOL(trace_gc_ignore_scavenger, false, 1140 "do not print trace line after scavenger collection") 1141 DEFINE_BOOL(trace_idle_notification, false, 1142 "print one trace line following each idle notification") 1143 DEFINE_BOOL(trace_idle_notification_verbose, false, 1144 "prints the heap state used by the idle notification") 1145 DEFINE_BOOL(trace_gc_verbose, false, 1146 "print more details following each garbage collection") 1147 DEFINE_IMPLICATION(trace_gc_verbose, trace_gc) 1148 DEFINE_BOOL(trace_gc_freelists, false, 1149 "prints details of each freelist before and after " 1150 "each major garbage collection") 1151 DEFINE_BOOL(trace_gc_freelists_verbose, false, 1152 "prints details of freelists of each page before and after " 1153 "each major garbage collection") 1154 DEFINE_IMPLICATION(trace_gc_freelists_verbose, trace_gc_freelists) 1155 DEFINE_BOOL(trace_evacuation_candidates, false, 1156 "Show statistics about the pages evacuation by the compaction") 1157 DEFINE_BOOL( 1158 trace_allocations_origins, false, 1159 "Show statistics about the origins of allocations. " 1160 "Combine with --no-inline-new to track allocations from generated code") 1161 DEFINE_BOOL(trace_pending_allocations, false, 1162 "trace calls to Heap::IsAllocationPending that return true") 1163 1164 DEFINE_INT(trace_allocation_stack_interval, -1, 1165 "print stack trace after <n> free-list allocations") 1166 DEFINE_INT(trace_duplicate_threshold_kb, 0, 1167 "print duplicate objects in the heap if their size is more than " 1168 "given threshold") 1169 DEFINE_BOOL(trace_fragmentation, false, "report fragmentation for old space") 1170 DEFINE_BOOL(trace_fragmentation_verbose, false, 1171 "report fragmentation for old space (detailed)") 1172 DEFINE_BOOL(minor_mc_trace_fragmentation, false, 1173 "trace fragmentation after marking") 1174 DEFINE_BOOL(trace_evacuation, false, "report evacuation statistics") 1175 DEFINE_BOOL(trace_mutator_utilization, false, 1176 "print mutator utilization, allocation speed, gc speed") 1177 DEFINE_BOOL(incremental_marking, true, "use incremental marking") 1178 DEFINE_BOOL(incremental_marking_wrappers, true, 1179 "use incremental marking for marking wrappers") 1180 DEFINE_BOOL(incremental_marking_task, true, "use tasks for incremental marking") 1181 DEFINE_INT(incremental_marking_soft_trigger, 0, 1182 "threshold for starting incremental marking via a task in percent " 1183 "of available space: limit - size") 1184 DEFINE_INT(incremental_marking_hard_trigger, 0, 1185 "threshold for starting incremental marking immediately in percent " 1186 "of available space: limit - size") 1187 DEFINE_BOOL(trace_unmapper, false, "Trace the unmapping") 1188 DEFINE_BOOL(parallel_scavenge, true, "parallel scavenge") 1189 DEFINE_BOOL(scavenge_task, true, "schedule scavenge tasks") 1190 DEFINE_INT(scavenge_task_trigger, 80, 1191 "scavenge task trigger in percent of the current heap limit") 1192 DEFINE_BOOL(scavenge_separate_stack_scanning, false, 1193 "use a separate phase for stack scanning in scavenge") 1194 DEFINE_BOOL(trace_parallel_scavenge, false, "trace parallel scavenge") 1195 #if MUST_WRITE_PROTECT_CODE_MEMORY 1196 DEFINE_BOOL_READONLY(write_protect_code_memory, true, 1197 "write protect code memory") 1198 #else 1199 DEFINE_BOOL(write_protect_code_memory, true, "write protect code memory") 1200 #endif 1201 #if defined(V8_ATOMIC_MARKING_STATE) && defined(V8_ATOMIC_OBJECT_FIELD_WRITES) 1202 #define V8_CONCURRENT_MARKING_BOOL true 1203 #else 1204 #define V8_CONCURRENT_MARKING_BOOL false 1205 #endif 1206 DEFINE_BOOL(concurrent_marking, V8_CONCURRENT_MARKING_BOOL, 1207 "use concurrent marking") 1208 DEFINE_BOOL(concurrent_array_buffer_sweeping, true, 1209 "concurrently sweep array buffers") 1210 DEFINE_BOOL(stress_concurrent_allocation, false, 1211 "start background threads that allocate memory") 1212 DEFINE_BOOL(parallel_marking, V8_CONCURRENT_MARKING_BOOL, 1213 "use parallel marking in atomic pause") 1214 DEFINE_INT(ephemeron_fixpoint_iterations, 10, 1215 "number of fixpoint iterations it takes to switch to linear " 1216 "ephemeron algorithm") 1217 DEFINE_BOOL(trace_concurrent_marking, false, "trace concurrent marking") 1218 DEFINE_BOOL(concurrent_sweeping, true, "use concurrent sweeping") 1219 DEFINE_BOOL(parallel_compaction, true, "use parallel compaction") 1220 DEFINE_BOOL(parallel_pointer_update, true, 1221 "use parallel pointer update during compaction") 1222 DEFINE_BOOL(detect_ineffective_gcs_near_heap_limit, true, 1223 "trigger out-of-memory failure to avoid GC storm near heap limit") 1224 DEFINE_BOOL(trace_incremental_marking, false, 1225 "trace progress of the incremental marking") 1226 DEFINE_BOOL(trace_stress_marking, false, "trace stress marking progress") 1227 DEFINE_BOOL(trace_stress_scavenge, false, "trace stress scavenge progress") 1228 DEFINE_BOOL(track_gc_object_stats, false, 1229 "track object counts and memory usage") 1230 DEFINE_BOOL(trace_gc_object_stats, false, 1231 "trace object counts and memory usage") 1232 DEFINE_BOOL(trace_zone_stats, false, "trace zone memory usage") 1233 DEFINE_GENERIC_IMPLICATION( 1234 trace_zone_stats, 1235 TracingFlags::zone_stats.store( 1236 v8::tracing::TracingCategoryObserver::ENABLED_BY_NATIVE)) 1237 DEFINE_SIZE_T( 1238 zone_stats_tolerance, 1 * MB, 1239 "report a tick only when allocated zone memory changes by this amount") 1240 DEFINE_BOOL(trace_zone_type_stats, false, "trace per-type zone memory usage") 1241 DEFINE_GENERIC_IMPLICATION( 1242 trace_zone_type_stats, 1243 TracingFlags::zone_stats.store( 1244 v8::tracing::TracingCategoryObserver::ENABLED_BY_NATIVE)) 1245 DEFINE_BOOL(track_retaining_path, false, 1246 "enable support for tracking retaining path") 1247 DEFINE_DEBUG_BOOL(trace_backing_store, false, "trace backing store events") 1248 DEFINE_INT(gc_stats, 0, "Used by tracing internally to enable gc statistics") 1249 DEFINE_IMPLICATION(trace_gc_object_stats, track_gc_object_stats) 1250 DEFINE_GENERIC_IMPLICATION( 1251 track_gc_object_stats, 1252 TracingFlags::gc_stats.store( 1253 v8::tracing::TracingCategoryObserver::ENABLED_BY_NATIVE)) 1254 DEFINE_GENERIC_IMPLICATION( 1255 trace_gc_object_stats, 1256 TracingFlags::gc_stats.store( 1257 v8::tracing::TracingCategoryObserver::ENABLED_BY_NATIVE)) 1258 DEFINE_NEG_IMPLICATION(trace_gc_object_stats, incremental_marking) 1259 DEFINE_NEG_IMPLICATION(track_retaining_path, parallel_marking) 1260 DEFINE_NEG_IMPLICATION(track_retaining_path, concurrent_marking) 1261 DEFINE_BOOL(track_detached_contexts, true, 1262 "track native contexts that are expected to be garbage collected") 1263 DEFINE_BOOL(trace_detached_contexts, false, 1264 "trace native contexts that are expected to be garbage collected") 1265 DEFINE_IMPLICATION(trace_detached_contexts, track_detached_contexts) 1266 #ifdef VERIFY_HEAP 1267 DEFINE_BOOL(verify_heap, false, "verify heap pointers before and after GC") 1268 DEFINE_BOOL(verify_heap_skip_remembered_set, false, 1269 "disable remembered set verification") 1270 #endif 1271 DEFINE_BOOL(move_object_start, true, "enable moving of object starts") 1272 DEFINE_BOOL(memory_reducer, true, "use memory reducer") 1273 DEFINE_BOOL(memory_reducer_for_small_heaps, true, 1274 "use memory reducer for small heaps") 1275 DEFINE_INT(heap_growing_percent, 0, 1276 "specifies heap growing factor as (1 + heap_growing_percent/100)") 1277 DEFINE_INT(v8_os_page_size, 0, "override OS page size (in KBytes)") 1278 DEFINE_BOOL(allocation_buffer_parking, true, "allocation buffer parking") 1279 DEFINE_BOOL(always_compact, false, "Perform compaction on every full GC") 1280 DEFINE_BOOL(never_compact, false, 1281 "Never perform compaction on full GC - testing only") 1282 DEFINE_BOOL(compact_code_space, true, "Compact code space on full collections") 1283 DEFINE_BOOL(flush_baseline_code, false, 1284 "flush of baseline code when it has not been executed recently") 1285 DEFINE_BOOL(flush_bytecode, true, 1286 "flush of bytecode when it has not been executed recently") 1287 DEFINE_BOOL(stress_flush_code, false, "stress code flushing") 1288 DEFINE_BOOL(trace_flush_bytecode, false, "trace bytecode flushing") 1289 DEFINE_BOOL(use_marking_progress_bar, true, 1290 "Use a progress bar to scan large objects in increments when " 1291 "incremental marking is active.") 1292 DEFINE_BOOL(stress_per_context_marking_worklist, false, 1293 "Use per-context worklist for marking") 1294 DEFINE_BOOL(force_marking_deque_overflows, false, 1295 "force overflows of marking deque by reducing it's size " 1296 "to 64 words") 1297 DEFINE_BOOL(stress_compaction, false, 1298 "stress the GC compactor to flush out bugs (implies " 1299 "--force_marking_deque_overflows)") 1300 DEFINE_BOOL(stress_compaction_random, false, 1301 "Stress GC compaction by selecting random percent of pages as " 1302 "evacuation candidates. It overrides stress_compaction.") 1303 DEFINE_BOOL(stress_incremental_marking, false, 1304 "force incremental marking for small heaps and run it more often") 1305 1306 DEFINE_BOOL(fuzzer_gc_analysis, false, 1307 "prints number of allocations and enables analysis mode for gc " 1308 "fuzz testing, e.g. --stress-marking, --stress-scavenge") 1309 DEFINE_INT(stress_marking, 0, 1310 "force marking at random points between 0 and X (inclusive) percent " 1311 "of the regular marking start limit") 1312 DEFINE_INT(stress_scavenge, 0, 1313 "force scavenge at random points between 0 and X (inclusive) " 1314 "percent of the new space capacity") 1315 DEFINE_VALUE_IMPLICATION(fuzzer_gc_analysis, stress_marking, 99) 1316 DEFINE_VALUE_IMPLICATION(fuzzer_gc_analysis, stress_scavenge, 99) 1317 DEFINE_BOOL( 1318 reclaim_unmodified_wrappers, true, 1319 "reclaim otherwise unreachable unmodified wrapper objects when possible") 1320 1321 // These flags will be removed after experiments. Do not rely on them. 1322 DEFINE_BOOL(gc_experiment_less_compaction, false, 1323 "less compaction in non-memory reducing mode") 1324 1325 DEFINE_BOOL(disable_abortjs, false, "disables AbortJS runtime function") 1326 1327 DEFINE_BOOL(randomize_all_allocations, false, 1328 "randomize virtual memory reservations by ignoring any hints " 1329 "passed when allocating pages") 1330 1331 DEFINE_BOOL(manual_evacuation_candidates_selection, false, 1332 "Test mode only flag. It allows an unit test to select evacuation " 1333 "candidates pages (requires --stress_compaction).") 1334 DEFINE_BOOL(fast_promotion_new_space, false, 1335 "fast promote new space on high survival rates") 1336 1337 DEFINE_BOOL(clear_free_memory, false, "initialize free memory with 0") 1338 1339 DEFINE_BOOL(crash_on_aborted_evacuation, false, 1340 "crash when evacuation of page fails") 1341 1342 DEFINE_BOOL_READONLY( 1343 young_generation_large_objects, true, 1344 "allocates large objects by default in the young generation large " 1345 "object space") 1346 1347 // assembler-ia32.cc / assembler-arm.cc / assembler-arm64.cc / assembler-x64.cc 1348 #ifdef V8_ENABLE_DEBUG_CODE 1349 DEFINE_BOOL(debug_code, DEBUG_BOOL, 1350 "generate extra code (assertions) for debugging") 1351 #else 1352 DEFINE_BOOL_READONLY(debug_code, false, "") 1353 #endif 1354 #ifdef V8_CODE_COMMENTS 1355 DEFINE_BOOL(code_comments, false, 1356 "emit comments in code disassembly; for more readable source " 1357 "positions you should add --no-concurrent_recompilation") 1358 #else 1359 DEFINE_BOOL_READONLY(code_comments, false, "") 1360 #endif 1361 DEFINE_BOOL(enable_sse3, true, "enable use of SSE3 instructions if available") 1362 DEFINE_BOOL(enable_ssse3, true, "enable use of SSSE3 instructions if available") 1363 DEFINE_BOOL(enable_sse4_1, true, 1364 "enable use of SSE4.1 instructions if available") 1365 DEFINE_BOOL(enable_sse4_2, true, 1366 "enable use of SSE4.2 instructions if available") 1367 DEFINE_BOOL(enable_sahf, true, 1368 "enable use of SAHF instruction if available (X64 only)") 1369 DEFINE_BOOL(enable_avx, true, "enable use of AVX instructions if available") 1370 DEFINE_BOOL(enable_avx2, true, "enable use of AVX2 instructions if available") 1371 DEFINE_BOOL(enable_fma3, true, "enable use of FMA3 instructions if available") 1372 DEFINE_BOOL(enable_bmi1, true, "enable use of BMI1 instructions if available") 1373 DEFINE_BOOL(enable_bmi2, true, "enable use of BMI2 instructions if available") 1374 DEFINE_BOOL(enable_lzcnt, true, "enable use of LZCNT instruction if available") 1375 DEFINE_BOOL(enable_popcnt, true, 1376 "enable use of POPCNT instruction if available") 1377 DEFINE_STRING(arm_arch, ARM_ARCH_DEFAULT, 1378 "generate instructions for the selected ARM architecture if " 1379 "available: armv6, armv7, armv7+sudiv or armv8") 1380 DEFINE_BOOL(force_long_branches, false, 1381 "force all emitted branches to be in long mode (MIPS/PPC only)") 1382 DEFINE_STRING(mcpu, "auto", "enable optimization for specific cpu") 1383 DEFINE_BOOL(partial_constant_pool, true, 1384 "enable use of partial constant pools (X64 only)") 1385 DEFINE_STRING(sim_arm64_optional_features, "none", 1386 "enable optional features on the simulator for testing: none or " 1387 "all") 1388 1389 #if defined(V8_TARGET_ARCH_RISCV64) 1390 DEFINE_BOOL(riscv_trap_to_simulator_debugger, false, 1391 "enable simulator trap to debugger") 1392 DEFINE_BOOL(riscv_debug, false, "enable debug prints") 1393 1394 DEFINE_BOOL(riscv_constant_pool, true, 1395 "enable constant pool (RISCV only)") 1396 1397 DEFINE_BOOL(riscv_c_extension, false, 1398 "enable compressed extension isa variant (RISCV only)") 1399 #endif 1400 1401 // Controlling source positions for Torque/CSA code. 1402 DEFINE_BOOL(enable_source_at_csa_bind, false, 1403 "Include source information in the binary at CSA bind locations.") 1404 1405 // Deprecated ARM flags (replaced by arm_arch). 1406 DEFINE_MAYBE_BOOL(enable_armv7, "deprecated (use --arm_arch instead)") 1407 DEFINE_MAYBE_BOOL(enable_vfp3, "deprecated (use --arm_arch instead)") 1408 DEFINE_MAYBE_BOOL(enable_32dregs, "deprecated (use --arm_arch instead)") 1409 DEFINE_MAYBE_BOOL(enable_neon, "deprecated (use --arm_arch instead)") 1410 DEFINE_MAYBE_BOOL(enable_sudiv, "deprecated (use --arm_arch instead)") 1411 DEFINE_MAYBE_BOOL(enable_armv8, "deprecated (use --arm_arch instead)") 1412 1413 // regexp-macro-assembler-*.cc 1414 DEFINE_BOOL(enable_regexp_unaligned_accesses, true, 1415 "enable unaligned accesses for the regexp engine") 1416 1417 // api.cc 1418 DEFINE_BOOL(script_streaming, true, "enable parsing on background") 1419 DEFINE_BOOL(stress_background_compile, false, 1420 "stress test parsing on background") 1421 DEFINE_BOOL( 1422 finalize_streaming_on_background, true, 1423 "perform the script streaming finalization on the background thread") 1424 DEFINE_BOOL(concurrent_cache_deserialization, true, 1425 "enable deserializing code caches on background") 1426 // TODO(leszeks): Parallel compile tasks currently don't support off-thread 1427 // finalization. 1428 DEFINE_NEG_IMPLICATION(parallel_compile_tasks, finalize_streaming_on_background) 1429 DEFINE_BOOL(disable_old_api_accessors, false, 1430 "Disable old-style API accessors whose setters trigger through the " 1431 "prototype chain") 1432 DEFINE_BOOL( 1433 embedder_instance_types, false, 1434 "enable type checks based on instance types provided by the embedder") 1435 1436 // bootstrapper.cc 1437 DEFINE_BOOL(expose_gc, false, "expose gc extension") 1438 DEFINE_STRING(expose_gc_as, nullptr, 1439 "expose gc extension under the specified name") 1440 DEFINE_IMPLICATION(expose_gc_as, expose_gc) 1441 DEFINE_BOOL(expose_externalize_string, false, 1442 "expose externalize string extension") 1443 DEFINE_BOOL(expose_trigger_failure, false, "expose trigger-failure extension") 1444 DEFINE_BOOL(expose_ignition_statistics, false, 1445 "expose ignition-statistics extension (requires building with " 1446 "v8_enable_ignition_dispatch_counting)") 1447 DEFINE_INT(stack_trace_limit, 10, "number of stack frames to capture") 1448 DEFINE_BOOL(builtins_in_stack_traces, false, 1449 "show built-in functions in stack traces") 1450 DEFINE_BOOL(experimental_stack_trace_frames, false, 1451 "enable experimental frames (API/Builtins) and stack trace layout") 1452 DEFINE_BOOL(disallow_code_generation_from_strings, false, 1453 "disallow eval and friends") 1454 DEFINE_BOOL(expose_async_hooks, false, "expose async_hooks object") 1455 DEFINE_STRING(expose_cputracemark_as, nullptr, 1456 "expose cputracemark extension under the specified name") 1457 #ifdef ENABLE_VTUNE_TRACEMARK 1458 DEFINE_BOOL(enable_vtune_domain_support, true, "enable vtune domain support") 1459 #endif // ENABLE_VTUNE_TRACEMARK 1460 1461 // builtins.cc 1462 DEFINE_BOOL(allow_unsafe_function_constructor, false, 1463 "allow invoking the function constructor without security checks") 1464 DEFINE_BOOL(force_slow_path, false, "always take the slow path for builtins") 1465 DEFINE_BOOL(test_small_max_function_context_stub_size, false, 1466 "enable testing the function context size overflow path " 1467 "by making the maximum size smaller") 1468 1469 DEFINE_BOOL(inline_new, true, "use fast inline allocation") 1470 DEFINE_NEG_NEG_IMPLICATION(inline_new, turbo_allocation_folding) 1471 1472 // bytecode-generator.cc 1473 DEFINE_INT(switch_table_spread_threshold, 3, 1474 "allow the jump table used for switch statements to span a range " 1475 "of integers roughly equal to this number times the number of " 1476 "clauses in the switch") 1477 DEFINE_INT(switch_table_min_cases, 6, 1478 "the number of Smi integer cases present in the switch statement " 1479 "before using the jump table optimization") 1480 1481 // codegen-ia32.cc / codegen-arm.cc 1482 DEFINE_BOOL(trace, false, "trace javascript function calls") 1483 1484 // codegen.cc 1485 DEFINE_BOOL(lazy, true, "use lazy compilation") 1486 DEFINE_BOOL(lazy_eval, true, "use lazy compilation during eval") 1487 DEFINE_BOOL(lazy_streaming, true, 1488 "use lazy compilation during streaming compilation") 1489 DEFINE_BOOL(max_lazy, false, "ignore eager compilation hints") 1490 DEFINE_IMPLICATION(max_lazy, lazy) 1491 DEFINE_BOOL(trace_opt, false, "trace optimized compilation") 1492 DEFINE_BOOL(trace_opt_verbose, false, 1493 "extra verbose optimized compilation tracing") 1494 DEFINE_IMPLICATION(trace_opt_verbose, trace_opt) 1495 DEFINE_BOOL(trace_opt_stats, false, "trace optimized compilation statistics") 1496 DEFINE_BOOL(trace_deopt, false, "trace deoptimization") 1497 DEFINE_BOOL(log_deopt, false, "log deoptimization") 1498 DEFINE_BOOL(trace_deopt_verbose, false, "extra verbose deoptimization tracing") 1499 DEFINE_IMPLICATION(trace_deopt_verbose, trace_deopt) 1500 DEFINE_BOOL(trace_file_names, false, 1501 "include file names in trace-opt/trace-deopt output") 1502 DEFINE_BOOL(always_opt, false, "always try to optimize functions") 1503 DEFINE_IMPLICATION(always_opt, opt) 1504 DEFINE_BOOL(always_osr, false, "always try to OSR functions") 1505 DEFINE_BOOL(prepare_always_opt, false, "prepare for turning on always opt") 1506 1507 DEFINE_BOOL(trace_serializer, false, "print code serializer trace") 1508 #ifdef DEBUG 1509 DEFINE_BOOL(external_reference_stats, false, 1510 "print statistics on external references used during serialization") 1511 #endif // DEBUG 1512 1513 // compilation-cache.cc 1514 DEFINE_BOOL(compilation_cache, true, "enable compilation cache") 1515 1516 DEFINE_BOOL(cache_prototype_transitions, true, "cache prototype transitions") 1517 1518 // lazy-compile-dispatcher.cc 1519 DEFINE_BOOL(parallel_compile_tasks, false, "enable parallel compile tasks") 1520 DEFINE_BOOL(lazy_compile_dispatcher, false, "enable compiler dispatcher") 1521 DEFINE_IMPLICATION(parallel_compile_tasks, lazy_compile_dispatcher) 1522 DEFINE_BOOL(trace_compiler_dispatcher, false, 1523 "trace compiler dispatcher activity") 1524 1525 // cpu-profiler.cc 1526 DEFINE_INT(cpu_profiler_sampling_interval, 1000, 1527 "CPU profiler sampling interval in microseconds") 1528 1529 // debugger 1530 DEFINE_BOOL( 1531 trace_side_effect_free_debug_evaluate, false, 1532 "print debug messages for side-effect-free debug-evaluate for testing") 1533 DEFINE_BOOL(hard_abort, true, "abort by crashing") 1534 1535 // disassembler 1536 DEFINE_BOOL(log_colour, ENABLE_LOG_COLOUR, 1537 "When logging, try to use coloured output.") 1538 1539 // inspector 1540 DEFINE_BOOL(expose_inspector_scripts, false, 1541 "expose injected-script-source.js for debugging") 1542 1543 // execution.cc 1544 DEFINE_INT(stack_size, V8_DEFAULT_STACK_SIZE_KB, 1545 "default size of stack region v8 is allowed to use (in kBytes)") 1546 1547 // frames.cc 1548 DEFINE_INT(max_stack_trace_source_length, 300, 1549 "maximum length of function source code printed in a stack trace.") 1550 1551 // execution.cc, messages.cc 1552 DEFINE_BOOL(clear_exceptions_on_js_entry, false, 1553 "clear pending exceptions when entering JavaScript") 1554 1555 // counters.cc 1556 DEFINE_INT(histogram_interval, 600000, 1557 "time interval in ms for aggregating memory histograms") 1558 1559 // heap-snapshot-generator.cc 1560 DEFINE_BOOL(heap_profiler_trace_objects, false, 1561 "Dump heap object allocations/movements/size_updates") 1562 DEFINE_BOOL(heap_profiler_use_embedder_graph, true, 1563 "Use the new EmbedderGraph API to get embedder nodes") 1564 DEFINE_INT(heap_snapshot_string_limit, 1024, 1565 "truncate strings to this length in the heap snapshot") 1566 DEFINE_BOOL(heap_profiler_show_hidden_objects, false, 1567 "use 'native' rather than 'hidden' node type in snapshot") 1568 1569 // sampling-heap-profiler.cc 1570 DEFINE_BOOL(sampling_heap_profiler_suppress_randomness, false, 1571 "Use constant sample intervals to eliminate test flakiness") 1572 1573 // v8.cc 1574 DEFINE_BOOL(use_idle_notification, true, 1575 "Use idle notification to reduce memory footprint.") 1576 // ic.cc 1577 DEFINE_BOOL(log_ic, false, 1578 "Log inline cache state transitions for tools/ic-processor") 1579 DEFINE_IMPLICATION(log_ic, log_code) 1580 DEFINE_GENERIC_IMPLICATION( 1581 log_ic, TracingFlags::ic_stats.store( 1582 v8::tracing::TracingCategoryObserver::ENABLED_BY_NATIVE)) 1583 DEFINE_BOOL_READONLY(fast_map_update, false, 1584 "enable fast map update by caching the migration target") 1585 DEFINE_INT(max_valid_polymorphic_map_count, 4, 1586 "maximum number of valid maps to track in POLYMORPHIC state") 1587 1588 DEFINE_BOOL(native_code_counters, DEBUG_BOOL, 1589 "generate extra code for manipulating stats counters") 1590 1591 DEFINE_BOOL(super_ic, true, "use an IC for super property loads") 1592 1593 DEFINE_BOOL(enable_mega_dom_ic, false, "use MegaDOM IC state for API objects") 1594 1595 // objects.cc 1596 DEFINE_BOOL(trace_prototype_users, false, 1597 "Trace updates to prototype user tracking") 1598 DEFINE_BOOL(trace_for_in_enumerate, false, "Trace for-in enumerate slow-paths") 1599 DEFINE_BOOL(log_maps, false, "Log map creation") 1600 DEFINE_BOOL(log_maps_details, true, "Also log map details") 1601 DEFINE_IMPLICATION(log_maps, log_code) 1602 1603 // parser.cc 1604 DEFINE_BOOL(allow_natives_syntax, false, "allow natives syntax") 1605 DEFINE_BOOL(allow_natives_for_differential_fuzzing, false, 1606 "allow only natives explicitly allowlisted for differential " 1607 "fuzzers") 1608 DEFINE_IMPLICATION(allow_natives_for_differential_fuzzing, allow_natives_syntax) 1609 DEFINE_IMPLICATION(allow_natives_for_differential_fuzzing, fuzzing) 1610 DEFINE_BOOL(parse_only, false, "only parse the sources") 1611 1612 // simulator-arm.cc, simulator-arm64.cc and simulator-mips.cc 1613 #ifdef USE_SIMULATOR 1614 DEFINE_BOOL(trace_sim, false, "Trace simulator execution") 1615 DEFINE_BOOL(debug_sim, false, "Enable debugging the simulator") 1616 DEFINE_BOOL(check_icache, false, 1617 "Check icache flushes in ARM and MIPS simulator") 1618 DEFINE_INT(stop_sim_at, 0, "Simulator stop after x number of instructions") 1619 #if defined(V8_TARGET_ARCH_ARM64) || defined(V8_TARGET_ARCH_MIPS64) || \ 1620 defined(V8_TARGET_ARCH_PPC64) || defined(V8_TARGET_ARCH_RISCV64) || \ 1621 defined(V8_TARGET_ARCH_LOONG64) 1622 DEFINE_INT(sim_stack_alignment, 16, 1623 "Stack alignment in bytes in simulator. This must be a power of two " 1624 "and it must be at least 16. 16 is default.") 1625 #else 1626 DEFINE_INT(sim_stack_alignment, 8, 1627 "Stack alingment in bytes in simulator (4 or 8, 8 is default)") 1628 #endif 1629 DEFINE_INT(sim_stack_size, 2 * MB / KB, 1630 "Stack size of the ARM64, MIPS, MIPS64 and PPC64 simulator " 1631 "in kBytes (default is 2 MB)") 1632 DEFINE_BOOL(trace_sim_messages, false, 1633 "Trace simulator debug messages. Implied by --trace-sim.") 1634 #endif // USE_SIMULATOR 1635 1636 #if defined V8_TARGET_ARCH_ARM64 1637 // pointer-auth-arm64.cc 1638 DEFINE_BOOL(sim_abort_on_bad_auth, true, 1639 "Stop execution when a pointer authentication fails in the " 1640 "ARM64 simulator.") 1641 #endif 1642 1643 // isolate.cc 1644 DEFINE_BOOL(async_stack_traces, true, 1645 "include async stack traces in Error.stack") 1646 DEFINE_BOOL(stack_trace_on_illegal, false, 1647 "print stack trace when an illegal exception is thrown") 1648 DEFINE_BOOL(abort_on_uncaught_exception, false, 1649 "abort program (dump core) when an uncaught exception is thrown") 1650 DEFINE_BOOL(correctness_fuzzer_suppressions, false, 1651 "Suppress certain unspecified behaviors to ease correctness " 1652 "fuzzing: Abort program when the stack overflows or a string " 1653 "exceeds maximum length (as opposed to throwing RangeError). " 1654 "Use a fixed suppression string for error messages.") 1655 DEFINE_BOOL(randomize_hashes, true, 1656 "randomize hashes to avoid predictable hash collisions " 1657 "(with snapshots this option cannot override the baked-in seed)") 1658 DEFINE_BOOL(rehash_snapshot, true, 1659 "rehash strings from the snapshot to override the baked-in seed") 1660 DEFINE_UINT64(hash_seed, 0, 1661 "Fixed seed to use to hash property keys (0 means random)" 1662 "(with snapshots this option cannot override the baked-in seed)") 1663 DEFINE_INT(random_seed, 0, 1664 "Default seed for initializing random generator " 1665 "(0, the default, means to use system random).") 1666 DEFINE_INT(fuzzer_random_seed, 0, 1667 "Default seed for initializing fuzzer random generator " 1668 "(0, the default, means to use v8's random number generator seed).") 1669 DEFINE_BOOL(trace_rail, false, "trace RAIL mode") 1670 DEFINE_BOOL(print_all_exceptions, false, 1671 "print exception object and stack trace on each thrown exception") 1672 DEFINE_BOOL( 1673 detailed_error_stack_trace, false, 1674 "includes arguments for each function call in the error stack frames array") 1675 DEFINE_BOOL(adjust_os_scheduling_parameters, true, 1676 "adjust OS specific scheduling params for the isolate") 1677 DEFINE_BOOL(experimental_flush_embedded_blob_icache, true, 1678 "Used in an experiment to evaluate icache flushing on certain CPUs") 1679 1680 // Flags for short builtin calls feature 1681 #undef FLAG 1682 #if V8_SHORT_BUILTIN_CALLS 1683 #define FLAG FLAG_FULL 1684 #define V8_SHORT_BUILTIN_CALLS_BOOL true 1685 #else 1686 #define FLAG FLAG_READONLY 1687 #define V8_SHORT_BUILTIN_CALLS_BOOL false 1688 #endif 1689 1690 DEFINE_BOOL(short_builtin_calls, V8_SHORT_BUILTIN_CALLS_BOOL, 1691 "Put embedded builtins code into the code range for shorter " 1692 "builtin calls/jumps if system has >=4GB memory") 1693 1694 #undef FLAG 1695 #define FLAG FLAG_FULL 1696 1697 // runtime.cc 1698 DEFINE_BOOL(runtime_call_stats, false, "report runtime call counts and times") 1699 DEFINE_GENERIC_IMPLICATION( 1700 runtime_call_stats, 1701 TracingFlags::runtime_stats.store( 1702 v8::tracing::TracingCategoryObserver::ENABLED_BY_NATIVE)) 1703 DEFINE_BOOL(rcs, false, "report runtime call counts and times") 1704 DEFINE_IMPLICATION(rcs, runtime_call_stats) 1705 1706 DEFINE_BOOL(rcs_cpu_time, false, 1707 "report runtime times in cpu time (the default is wall time)") 1708 DEFINE_IMPLICATION(rcs_cpu_time, rcs) 1709 1710 // snapshot-common.cc 1711 DEFINE_BOOL(skip_snapshot_checksum, false, 1712 "Skip snapshot checksum calculation when deserializing an Isolate.") 1713 DEFINE_BOOL(profile_deserialization, false, 1714 "Print the time it takes to deserialize the snapshot.") 1715 DEFINE_BOOL(serialization_statistics, false, 1716 "Collect statistics on serialized objects.") 1717 // Regexp 1718 DEFINE_BOOL(regexp_optimization, true, "generate optimized regexp code") 1719 DEFINE_BOOL(regexp_interpret_all, false, "interpret all regexp code") 1720 #ifdef V8_TARGET_BIG_ENDIAN 1721 #define REGEXP_PEEPHOLE_OPTIMIZATION_BOOL false 1722 #else 1723 #define REGEXP_PEEPHOLE_OPTIMIZATION_BOOL true 1724 #endif 1725 DEFINE_BOOL(regexp_tier_up, true, 1726 "enable regexp interpreter and tier up to the compiler after the " 1727 "number of executions set by the tier up ticks flag") 1728 DEFINE_NEG_IMPLICATION(regexp_interpret_all, regexp_tier_up) 1729 DEFINE_INT(regexp_tier_up_ticks, 1, 1730 "set the number of executions for the regexp interpreter before " 1731 "tiering-up to the compiler") 1732 DEFINE_BOOL(regexp_peephole_optimization, REGEXP_PEEPHOLE_OPTIMIZATION_BOOL, 1733 "enable peephole optimization for regexp bytecode") 1734 DEFINE_BOOL(trace_regexp_peephole_optimization, false, 1735 "trace regexp bytecode peephole optimization") 1736 DEFINE_BOOL(trace_regexp_bytecodes, false, "trace regexp bytecode execution") 1737 DEFINE_BOOL(trace_regexp_assembler, false, 1738 "trace regexp macro assembler calls.") 1739 DEFINE_BOOL(trace_regexp_parser, false, "trace regexp parsing") 1740 DEFINE_BOOL(trace_regexp_tier_up, false, "trace regexp tiering up execution") 1741 DEFINE_BOOL(trace_regexp_graph, false, "trace the regexp graph") 1742 1743 DEFINE_BOOL(enable_experimental_regexp_engine, false, 1744 "recognize regexps with 'l' flag, run them on experimental engine") 1745 DEFINE_BOOL(default_to_experimental_regexp_engine, false, 1746 "run regexps with the experimental engine where possible") 1747 DEFINE_IMPLICATION(default_to_experimental_regexp_engine, 1748 enable_experimental_regexp_engine) 1749 DEFINE_BOOL(trace_experimental_regexp_engine, false, 1750 "trace execution of experimental regexp engine") 1751 1752 DEFINE_BOOL(enable_experimental_regexp_engine_on_excessive_backtracks, false, 1753 "fall back to a breadth-first regexp engine on excessive " 1754 "backtracking") 1755 DEFINE_UINT(regexp_backtracks_before_fallback, 50000, 1756 "number of backtracks during regexp execution before fall back " 1757 "to experimental engine if " 1758 "enable_experimental_regexp_engine_on_excessive_backtracks is set") 1759 1760 // Testing flags test/cctest/test-{flags,api,serialization}.cc 1761 DEFINE_BOOL(testing_bool_flag, true, "testing_bool_flag") 1762 DEFINE_MAYBE_BOOL(testing_maybe_bool_flag, "testing_maybe_bool_flag") 1763 DEFINE_INT(testing_int_flag, 13, "testing_int_flag") 1764 DEFINE_FLOAT(testing_float_flag, 2.5, "float-flag") 1765 DEFINE_STRING(testing_string_flag, "Hello, world!", "string-flag") 1766 DEFINE_INT(testing_prng_seed, 42, "Seed used for threading test randomness") 1767 1768 // Test flag for a check in %OptimizeFunctionOnNextCall 1769 DEFINE_BOOL( 1770 testing_d8_test_runner, false, 1771 "test runner turns on this flag to enable a check that the function was " 1772 "prepared for optimization before marking it for optimization") 1773 1774 DEFINE_BOOL( 1775 fuzzing, false, 1776 "Fuzzers use this flag to signal that they are ... fuzzing. This causes " 1777 "intrinsics to fail silently (e.g. return undefined) on invalid usage.") 1778 1779 // mksnapshot.cc 1780 DEFINE_STRING(embedded_src, nullptr, 1781 "Path for the generated embedded data file. (mksnapshot only)") 1782 DEFINE_STRING( 1783 embedded_variant, nullptr, 1784 "Label to disambiguate symbols in embedded data file. (mksnapshot only)") 1785 DEFINE_STRING(startup_src, nullptr, 1786 "Write V8 startup as C++ src. (mksnapshot only)") 1787 DEFINE_STRING(startup_blob, nullptr, 1788 "Write V8 startup blob file. (mksnapshot only)") 1789 DEFINE_STRING(target_arch, nullptr, 1790 "The mksnapshot target arch. (mksnapshot only)") 1791 DEFINE_STRING(target_os, nullptr, "The mksnapshot target os. (mksnapshot only)") 1792 DEFINE_BOOL(target_is_simulator, false, 1793 "Instruct mksnapshot that the target is meant to run in the " 1794 "simulator and it can generate simulator-specific instructions. " 1795 "(mksnapshot only)") 1796 DEFINE_STRING(turbo_profiling_log_file, nullptr, 1797 "Path of the input file containing basic block counters for " 1798 "builtins. (mksnapshot only)") 1799 1800 // On some platforms, the .text section only has execute permissions. 1801 DEFINE_BOOL(text_is_readable, true, 1802 "Whether the .text section of binary can be read") 1803 DEFINE_NEG_NEG_IMPLICATION(text_is_readable, partial_constant_pool) 1804 1805 // 1806 // Minor mark compact collector flags. 1807 // 1808 #ifdef ENABLE_MINOR_MC 1809 DEFINE_BOOL(trace_minor_mc_parallel_marking, false, 1810 "trace parallel marking for the young generation") 1811 DEFINE_BOOL(minor_mc, false, "perform young generation mark compact GCs") 1812 #else 1813 DEFINE_BOOL_READONLY(minor_mc, false, 1814 "perform young generation mark compact GCs") 1815 #endif // ENABLE_MINOR_MC 1816 1817 // 1818 // Dev shell flags 1819 // 1820 1821 DEFINE_BOOL(help, false, "Print usage message, including flags, on console") 1822 DEFINE_BOOL(print_flag_values, false, "Print all flag values of V8") 1823 1824 DEFINE_BOOL(dump_counters, false, "Dump counters on exit") 1825 DEFINE_BOOL(slow_histograms, false, 1826 "Enable slow histograms with more overhead.") 1827 DEFINE_IMPLICATION(dump_counters, slow_histograms) 1828 1829 DEFINE_BOOL(dump_counters_nvp, false, 1830 "Dump counters as name-value pairs on exit") 1831 DEFINE_BOOL(use_external_strings, false, "Use external strings for source code") 1832 DEFINE_STRING(map_counters, "", "Map counters to a file") 1833 DEFINE_BOOL(mock_arraybuffer_allocator, false, 1834 "Use a mock ArrayBuffer allocator for testing.") 1835 DEFINE_SIZE_T(mock_arraybuffer_allocator_limit, 0, 1836 "Memory limit for mock ArrayBuffer allocator used to simulate " 1837 "OOM for testing.") 1838 #if MULTI_MAPPED_ALLOCATOR_AVAILABLE 1839 DEFINE_BOOL(multi_mapped_mock_allocator, false, 1840 "Use a multi-mapped mock ArrayBuffer allocator for testing.") 1841 #endif 1842 1843 // 1844 // GDB JIT integration flags. 1845 // 1846 #undef FLAG 1847 #ifdef ENABLE_GDB_JIT_INTERFACE 1848 #define FLAG FLAG_FULL 1849 #else 1850 #define FLAG FLAG_READONLY 1851 #endif 1852 1853 DEFINE_BOOL(gdbjit, false, "enable GDBJIT interface") 1854 DEFINE_BOOL(gdbjit_full, false, "enable GDBJIT interface for all code objects") 1855 DEFINE_BOOL(gdbjit_dump, false, "dump elf objects with debug info to disk") 1856 DEFINE_STRING(gdbjit_dump_filter, "", 1857 "dump only objects containing this substring") 1858 1859 #ifdef ENABLE_GDB_JIT_INTERFACE 1860 DEFINE_IMPLICATION(gdbjit_full, gdbjit) 1861 DEFINE_IMPLICATION(gdbjit_dump, gdbjit) 1862 #endif 1863 DEFINE_NEG_IMPLICATION(gdbjit, compact_code_space) 1864 1865 // 1866 // Debug only flags 1867 // 1868 #undef FLAG 1869 #ifdef DEBUG 1870 #define FLAG FLAG_FULL 1871 #else 1872 #define FLAG FLAG_READONLY 1873 #endif 1874 1875 // checks.cc 1876 #ifdef ENABLE_SLOW_DCHECKS 1877 DEFINE_BOOL(enable_slow_asserts, true, 1878 "enable asserts that are slow to execute") 1879 #endif 1880 1881 // codegen-ia32.cc / codegen-arm.cc / macro-assembler-*.cc 1882 DEFINE_BOOL(print_ast, false, "print source AST") 1883 DEFINE_BOOL(trap_on_abort, false, "replace aborts by breakpoints") 1884 1885 // compiler.cc 1886 DEFINE_BOOL(print_scopes, false, "print scopes") 1887 1888 // contexts.cc 1889 DEFINE_BOOL(trace_contexts, false, "trace contexts operations") 1890 1891 // heap.cc 1892 DEFINE_BOOL(gc_verbose, false, "print stuff during garbage collection") 1893 DEFINE_BOOL(code_stats, false, "report code statistics after GC") 1894 DEFINE_BOOL(print_handles, false, "report handles after GC") 1895 DEFINE_BOOL(check_handle_count, false, 1896 "Check that there are not too many handles at GC") 1897 DEFINE_BOOL(print_global_handles, false, "report global handles after GC") 1898 1899 // TurboFan debug-only flags. 1900 DEFINE_BOOL(trace_turbo_escape, false, "enable tracing in escape analysis") 1901 1902 // objects.cc 1903 DEFINE_BOOL(trace_module_status, false, 1904 "Trace status transitions of ECMAScript modules") 1905 DEFINE_BOOL(trace_normalization, false, 1906 "prints when objects are turned into dictionaries.") 1907 1908 // runtime.cc 1909 DEFINE_BOOL(trace_lazy, false, "trace lazy compilation") 1910 1911 // spaces.cc 1912 DEFINE_BOOL(trace_isolates, false, "trace isolate state changes") 1913 1914 // Regexp 1915 DEFINE_BOOL(regexp_possessive_quantifier, false, 1916 "enable possessive quantifier syntax for testing") 1917 1918 // Debugger 1919 DEFINE_BOOL(print_break_location, false, "print source location on debug break") 1920 1921 // 1922 // Logging and profiling flags 1923 // 1924 // Logging flag dependencies are are also set separately in 1925 // V8::InitializeOncePerProcessImpl. Please add your flag to the log_all_flags 1926 // list in v8.cc to properly set FLAG_log and automatically enable it with 1927 // --log-all. 1928 #undef FLAG 1929 #define FLAG FLAG_FULL 1930 1931 // log.cc 1932 DEFINE_STRING(logfile, "v8.log", 1933 "Specify the name of the log file, use '-' for console, '+' for " 1934 "a temporary file.") 1935 DEFINE_BOOL(logfile_per_isolate, true, "Separate log files for each isolate.") 1936 1937 DEFINE_BOOL(log, false, 1938 "Minimal logging (no API, code, GC, suspect, or handles samples).") 1939 DEFINE_BOOL(log_all, false, "Log all events to the log file.") 1940 1941 DEFINE_BOOL(log_api, false, "Log API events to the log file.") 1942 DEFINE_BOOL(log_code, false, 1943 "Log code events to the log file without profiling.") 1944 DEFINE_BOOL(log_code_disassemble, false, 1945 "Log all disassembled code to the log file.") 1946 DEFINE_IMPLICATION(log_code_disassemble, log_code) 1947 DEFINE_BOOL(log_handles, false, "Log global handle events.") 1948 DEFINE_BOOL(log_suspect, false, "Log suspect operations.") 1949 DEFINE_BOOL(log_source_code, false, "Log source code.") 1950 DEFINE_BOOL(log_function_events, false, 1951 "Log function events " 1952 "(parse, compile, execute) separately.") 1953 1954 DEFINE_BOOL(detailed_line_info, false, 1955 "Always generate detailed line information for CPU profiling.") 1956 1957 #if defined(ANDROID) 1958 // Phones and tablets have processors that are much slower than desktop 1959 // and laptop computers for which current heuristics are tuned. 1960 #define DEFAULT_PROF_SAMPLING_INTERVAL 5000 1961 #else 1962 #define DEFAULT_PROF_SAMPLING_INTERVAL 1000 1963 #endif 1964 DEFINE_INT(prof_sampling_interval, DEFAULT_PROF_SAMPLING_INTERVAL, 1965 "Interval for --prof samples (in microseconds).") 1966 #undef DEFAULT_PROF_SAMPLING_INTERVAL 1967 1968 DEFINE_BOOL(prof_cpp, false, "Like --prof, but ignore generated code.") 1969 DEFINE_BOOL(prof_browser_mode, true, 1970 "Used with --prof, turns on browser-compatible mode for profiling.") 1971 1972 DEFINE_BOOL(prof, false, 1973 "Log statistical profiling information (implies --log-code).") 1974 DEFINE_IMPLICATION(prof, prof_cpp) 1975 DEFINE_IMPLICATION(prof, log_code) 1976 1977 DEFINE_BOOL(ll_prof, false, "Enable low-level linux profiler.") 1978 1979 #if V8_OS_LINUX 1980 #define DEFINE_PERF_PROF_BOOL(nam, cmt) DEFINE_BOOL(nam, false, cmt) 1981 #define DEFINE_PERF_PROF_IMPLICATION DEFINE_IMPLICATION 1982 #else 1983 #define DEFINE_PERF_PROF_BOOL(nam, cmt) DEFINE_BOOL_READONLY(nam, false, cmt) 1984 #define DEFINE_PERF_PROF_IMPLICATION(...) 1985 #endif 1986 1987 DEFINE_PERF_PROF_BOOL(perf_basic_prof, 1988 "Enable perf linux profiler (basic support).") 1989 DEFINE_NEG_IMPLICATION(perf_basic_prof, compact_code_space) 1990 DEFINE_PERF_PROF_BOOL( 1991 perf_basic_prof_only_functions, 1992 "Only report function code ranges to perf (i.e. no stubs).") 1993 DEFINE_PERF_PROF_IMPLICATION(perf_basic_prof_only_functions, perf_basic_prof) 1994 DEFINE_PERF_PROF_BOOL( 1995 perf_prof, "Enable perf linux profiler (experimental annotate support).") 1996 DEFINE_PERF_PROF_BOOL( 1997 perf_prof_annotate_wasm, 1998 "Used with --perf-prof, load wasm source map and provide annotate " 1999 "support (experimental).") 2000 DEFINE_PERF_PROF_BOOL( 2001 perf_prof_delete_file, 2002 "Remove the perf file right after creating it (for testing only).") 2003 DEFINE_NEG_IMPLICATION(perf_prof, compact_code_space) 2004 // TODO(v8:8462) Remove implication once perf supports remapping. 2005 #if !MUST_WRITE_PROTECT_CODE_MEMORY 2006 DEFINE_NEG_IMPLICATION(perf_prof, write_protect_code_memory) 2007 #endif 2008 #if V8_ENABLE_WEBASSEMBLY 2009 DEFINE_NEG_IMPLICATION(perf_prof, wasm_write_protect_code_memory) 2010 #endif // V8_ENABLE_WEBASSEMBLY 2011 2012 // --perf-prof-unwinding-info is available only on selected architectures. 2013 #if !V8_TARGET_ARCH_ARM && !V8_TARGET_ARCH_ARM64 && !V8_TARGET_ARCH_X64 && \ 2014 !V8_TARGET_ARCH_S390X && !V8_TARGET_ARCH_PPC64 2015 #undef DEFINE_PERF_PROF_BOOL 2016 #define DEFINE_PERF_PROF_BOOL(nam, cmt) DEFINE_BOOL_READONLY(nam, false, cmt) 2017 #undef DEFINE_PERF_PROF_IMPLICATION 2018 #define DEFINE_PERF_PROF_IMPLICATION(...) 2019 #endif 2020 2021 DEFINE_PERF_PROF_BOOL( 2022 perf_prof_unwinding_info, 2023 "Enable unwinding info for perf linux profiler (experimental).") 2024 DEFINE_PERF_PROF_IMPLICATION(perf_prof, perf_prof_unwinding_info) 2025 2026 #undef DEFINE_PERF_PROF_BOOL 2027 #undef DEFINE_PERF_PROF_IMPLICATION 2028 2029 DEFINE_STRING(gc_fake_mmap, "/tmp/__v8_gc__", 2030 "Specify the name of the file for fake gc mmap used in ll_prof") 2031 DEFINE_BOOL(log_internal_timer_events, false, "Time internal events.") 2032 DEFINE_IMPLICATION(log_internal_timer_events, prof) 2033 2034 DEFINE_BOOL(redirect_code_traces, false, 2035 "output deopt information and disassembly into file " 2036 "code-<pid>-<isolate id>.asm") 2037 DEFINE_STRING(redirect_code_traces_to, nullptr, 2038 "output deopt information and disassembly into the given file") 2039 2040 DEFINE_BOOL(print_opt_source, false, 2041 "print source code of optimized and inlined functions") 2042 2043 DEFINE_BOOL(vtune_prof_annotate_wasm, false, 2044 "Used when v8_enable_vtunejit is enabled, load wasm source map and " 2045 "provide annotate support (experimental).") 2046 2047 DEFINE_BOOL(win64_unwinding_info, true, "Enable unwinding info for Windows/x64") 2048 2049 #ifdef V8_TARGET_ARCH_ARM 2050 // Unsupported on arm. See https://crbug.com/v8/8713. 2051 DEFINE_BOOL_READONLY( 2052 interpreted_frames_native_stack, false, 2053 "Show interpreted frames on the native stack (useful for external " 2054 "profilers).") 2055 #else 2056 DEFINE_BOOL(interpreted_frames_native_stack, false, 2057 "Show interpreted frames on the native stack (useful for external " 2058 "profilers).") 2059 #endif 2060 2061 DEFINE_BOOL(enable_system_instrumentation, false, 2062 "Enable platform-specific profiling.") 2063 2064 #ifndef V8_TARGET_ARCH_ARM 2065 DEFINE_IMPLICATION(enable_system_instrumentation, 2066 interpreted_frames_native_stack) 2067 #endif 2068 2069 // 2070 // Disassembler only flags 2071 // 2072 #undef FLAG 2073 #ifdef ENABLE_DISASSEMBLER 2074 #define FLAG FLAG_FULL 2075 #else 2076 #define FLAG FLAG_READONLY 2077 #endif 2078 2079 // elements.cc 2080 DEFINE_BOOL(trace_elements_transitions, false, "trace elements transitions") 2081 2082 DEFINE_BOOL(trace_creation_allocation_sites, false, 2083 "trace the creation of allocation sites") 2084 2085 DEFINE_BOOL(print_code, false, "print generated code") 2086 DEFINE_BOOL(print_opt_code, false, "print optimized code") 2087 DEFINE_STRING(print_opt_code_filter, "*", "filter for printing optimized code") 2088 DEFINE_BOOL(print_code_verbose, false, "print more information for code") 2089 DEFINE_BOOL(print_builtin_code, false, "print generated code for builtins") 2090 DEFINE_STRING(print_builtin_code_filter, "*", 2091 "filter for printing builtin code") 2092 DEFINE_BOOL(print_regexp_code, false, "print generated regexp code") 2093 DEFINE_BOOL(print_regexp_bytecode, false, "print generated regexp bytecode") 2094 DEFINE_BOOL(print_builtin_size, false, "print code size for builtins") 2095 2096 #ifdef ENABLE_DISASSEMBLER 2097 DEFINE_BOOL(print_all_code, false, "enable all flags related to printing code") 2098 DEFINE_IMPLICATION(print_all_code, print_code) 2099 DEFINE_IMPLICATION(print_all_code, print_opt_code) 2100 DEFINE_IMPLICATION(print_all_code, print_code_verbose) 2101 DEFINE_IMPLICATION(print_all_code, print_builtin_code) 2102 DEFINE_IMPLICATION(print_all_code, print_regexp_code) 2103 #endif 2104 2105 #undef FLAG 2106 #define FLAG FLAG_FULL 2107 2108 // 2109 // Predictable mode related flags. 2110 // 2111 2112 DEFINE_BOOL(predictable, false, "enable predictable mode") 2113 DEFINE_NEG_IMPLICATION(predictable, memory_reducer) 2114 // TODO(v8:11848): These flags were recursively implied via --single-threaded 2115 // before. Audit them, and remove any unneeded implications. 2116 DEFINE_IMPLICATION(predictable, single_threaded_gc) 2117 DEFINE_NEG_IMPLICATION(predictable, concurrent_recompilation) 2118 DEFINE_NEG_IMPLICATION(predictable, lazy_compile_dispatcher) 2119 DEFINE_NEG_IMPLICATION(predictable, stress_concurrent_inlining) 2120 2121 DEFINE_BOOL(predictable_gc_schedule, false, 2122 "Predictable garbage collection schedule. Fixes heap growing, " 2123 "idle, and memory reducing behavior.") 2124 DEFINE_VALUE_IMPLICATION(predictable_gc_schedule, min_semi_space_size, 4) 2125 DEFINE_VALUE_IMPLICATION(predictable_gc_schedule, max_semi_space_size, 4) 2126 DEFINE_VALUE_IMPLICATION(predictable_gc_schedule, heap_growing_percent, 30) 2127 DEFINE_NEG_IMPLICATION(predictable_gc_schedule, memory_reducer) 2128 2129 // 2130 // Threading related flags. 2131 // 2132 2133 DEFINE_BOOL(single_threaded, false, "disable the use of background tasks") 2134 DEFINE_IMPLICATION(single_threaded, single_threaded_gc) 2135 DEFINE_NEG_IMPLICATION(single_threaded, concurrent_recompilation) 2136 DEFINE_NEG_IMPLICATION(single_threaded, lazy_compile_dispatcher) 2137 DEFINE_NEG_IMPLICATION(single_threaded, stress_concurrent_inlining) 2138 2139 // 2140 // Parallel and concurrent GC (Orinoco) related flags. 2141 // 2142 DEFINE_BOOL(single_threaded_gc, false, "disable the use of background gc tasks") 2143 DEFINE_NEG_IMPLICATION(single_threaded_gc, concurrent_marking) 2144 DEFINE_NEG_IMPLICATION(single_threaded_gc, concurrent_sweeping) 2145 DEFINE_NEG_IMPLICATION(single_threaded_gc, parallel_compaction) 2146 DEFINE_NEG_IMPLICATION(single_threaded_gc, parallel_marking) 2147 DEFINE_NEG_IMPLICATION(single_threaded_gc, parallel_pointer_update) 2148 DEFINE_NEG_IMPLICATION(single_threaded_gc, parallel_scavenge) 2149 DEFINE_NEG_IMPLICATION(single_threaded_gc, concurrent_array_buffer_sweeping) 2150 DEFINE_NEG_IMPLICATION(single_threaded_gc, stress_concurrent_allocation) 2151 2152 #undef FLAG 2153 2154 #ifdef VERIFY_PREDICTABLE 2155 #define FLAG FLAG_FULL 2156 #else 2157 #define FLAG FLAG_READONLY 2158 #endif 2159 2160 DEFINE_BOOL(verify_predictable, false, 2161 "this mode is used for checking that V8 behaves predictably") 2162 DEFINE_IMPLICATION(verify_predictable, predictable) 2163 DEFINE_INT(dump_allocations_digest_at_alloc, -1, 2164 "dump allocations digest each n-th allocation") 2165 2166 // 2167 // Read-only flags 2168 // 2169 #undef FLAG 2170 #define FLAG FLAG_READONLY 2171 2172 // assembler.h 2173 DEFINE_BOOL(enable_embedded_constant_pool, V8_EMBEDDED_CONSTANT_POOL, 2174 "enable use of embedded constant pools (PPC only)") 2175 2176 // Cleanup... 2177 #undef FLAG_FULL 2178 #undef FLAG_READONLY 2179 #undef FLAG 2180 #undef FLAG_ALIAS 2181 2182 #undef DEFINE_BOOL 2183 #undef DEFINE_MAYBE_BOOL 2184 #undef DEFINE_DEBUG_BOOL 2185 #undef DEFINE_INT 2186 #undef DEFINE_STRING 2187 #undef DEFINE_FLOAT 2188 #undef DEFINE_IMPLICATION 2189 #undef DEFINE_WEAK_IMPLICATION 2190 #undef DEFINE_NEG_IMPLICATION 2191 #undef DEFINE_NEG_VALUE_IMPLICATION 2192 #undef DEFINE_VALUE_IMPLICATION 2193 #undef DEFINE_WEAK_VALUE_IMPLICATION 2194 #undef DEFINE_GENERIC_IMPLICATION 2195 #undef DEFINE_ALIAS_BOOL 2196 #undef DEFINE_ALIAS_INT 2197 #undef DEFINE_ALIAS_STRING 2198 #undef DEFINE_ALIAS_FLOAT 2199 2200 #undef FLAG_MODE_DECLARE 2201 #undef FLAG_MODE_DEFINE 2202 #undef FLAG_MODE_DEFINE_DEFAULTS 2203 #undef FLAG_MODE_META 2204 #undef FLAG_MODE_DEFINE_IMPLICATIONS 2205 #undef FLAG_MODE_APPLY 2206 2207 #undef COMMA 2208