• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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 #define DEFINE_NEG_IMPLICATION(whenflag, thenflag)          \
19   DEFINE_VALUE_IMPLICATION(whenflag, thenflag, false)
20 
21 #define DEFINE_NEG_NEG_IMPLICATION(whenflag, thenflag) \
22   DEFINE_NEG_VALUE_IMPLICATION(whenflag, thenflag, false)
23 
24 // We want to declare the names of the variables for the header file.  Normally
25 // this will just be an extern declaration, but for a readonly flag we let the
26 // compiler make better optimizations by giving it the value.
27 #if defined(FLAG_MODE_DECLARE)
28 #define FLAG_FULL(ftype, ctype, nam, def, cmt) \
29   V8_EXPORT_PRIVATE extern ctype FLAG_##nam;
30 #define FLAG_READONLY(ftype, ctype, nam, def, cmt) \
31   static constexpr ctype FLAG_##nam = def;
32 
33 // We want to supply the actual storage and value for the flag variable in the
34 // .cc file.  We only do this for writable flags.
35 #elif defined(FLAG_MODE_DEFINE)
36 #ifdef USING_V8_SHARED
37 #define FLAG_FULL(ftype, ctype, nam, def, cmt) \
38   V8_EXPORT_PRIVATE extern ctype FLAG_##nam;
39 #else
40 #define FLAG_FULL(ftype, ctype, nam, def, cmt) \
41   V8_EXPORT_PRIVATE ctype FLAG_##nam = def;
42 #endif
43 
44 // We need to define all of our default values so that the Flag structure can
45 // access them by pointer.  These are just used internally inside of one .cc,
46 // for MODE_META, so there is no impact on the flags interface.
47 #elif defined(FLAG_MODE_DEFINE_DEFAULTS)
48 #define FLAG_FULL(ftype, ctype, nam, def, cmt) \
49   static constexpr ctype FLAGDEFAULT_##nam = def;
50 
51 // We want to write entries into our meta data table, for internal parsing and
52 // printing / etc in the flag parser code.  We only do this for writable flags.
53 #elif defined(FLAG_MODE_META)
54 #define FLAG_FULL(ftype, ctype, nam, def, cmt)                              \
55   { Flag::TYPE_##ftype, #nam, &FLAG_##nam, &FLAGDEFAULT_##nam, cmt, false } \
56   ,
57 #define FLAG_ALIAS(ftype, ctype, alias, nam)                     \
58   {                                                              \
59     Flag::TYPE_##ftype, #alias, &FLAG_##nam, &FLAGDEFAULT_##nam, \
60         "alias for --" #nam, false                               \
61   }                                                              \
62   ,
63 
64 // We produce the code to set flags when it is implied by another flag.
65 #elif defined(FLAG_MODE_DEFINE_IMPLICATIONS)
66 #define DEFINE_VALUE_IMPLICATION(whenflag, thenflag, value) \
67   if (FLAG_##whenflag) FLAG_##thenflag = value;
68 
69 #define DEFINE_NEG_VALUE_IMPLICATION(whenflag, thenflag, value) \
70   if (!FLAG_##whenflag) FLAG_##thenflag = value;
71 
72 #else
73 #error No mode supplied when including flags.defs
74 #endif
75 
76 // Dummy defines for modes where it is not relevant.
77 #ifndef FLAG_FULL
78 #define FLAG_FULL(ftype, ctype, nam, def, cmt)
79 #endif
80 
81 #ifndef FLAG_READONLY
82 #define FLAG_READONLY(ftype, ctype, nam, def, cmt)
83 #endif
84 
85 #ifndef FLAG_ALIAS
86 #define FLAG_ALIAS(ftype, ctype, alias, nam)
87 #endif
88 
89 #ifndef DEFINE_VALUE_IMPLICATION
90 #define DEFINE_VALUE_IMPLICATION(whenflag, thenflag, value)
91 #endif
92 
93 #ifndef DEFINE_NEG_VALUE_IMPLICATION
94 #define DEFINE_NEG_VALUE_IMPLICATION(whenflag, thenflag, value)
95 #endif
96 
97 #define COMMA ,
98 
99 #ifdef FLAG_MODE_DECLARE
100 // Structure used to hold a collection of arguments to the JavaScript code.
101 struct JSArguments {
102  public:
103   inline const char*& operator[](int idx) const { return argv[idx]; }
CreateJSArguments104   static JSArguments Create(int argc, const char** argv) {
105     JSArguments args;
106     args.argc = argc;
107     args.argv = argv;
108     return args;
109   }
110   int argc;
111   const char** argv;
112 };
113 
114 struct MaybeBoolFlag {
CreateMaybeBoolFlag115   static MaybeBoolFlag Create(bool has_value, bool value) {
116     MaybeBoolFlag flag;
117     flag.has_value = has_value;
118     flag.value = value;
119     return flag;
120   }
121   bool has_value;
122   bool value;
123 };
124 #endif
125 
126 #ifdef DEBUG
127 #define DEBUG_BOOL true
128 #else
129 #define DEBUG_BOOL false
130 #endif
131 
132 // Supported ARM configurations are:
133 //  "armv6":       ARMv6 + VFPv2
134 //  "armv7":       ARMv7 + VFPv3-D32 + NEON
135 //  "armv7+sudiv": ARMv7 + VFPv4-D32 + NEON + SUDIV
136 //  "armv8":       ARMv8 (including all of the above)
137 #if !defined(ARM_TEST_NO_FEATURE_PROBE) ||                            \
138     (defined(CAN_USE_ARMV8_INSTRUCTIONS) &&                           \
139      defined(CAN_USE_ARMV7_INSTRUCTIONS) && defined(CAN_USE_SUDIV) && \
140      defined(CAN_USE_NEON) && defined(CAN_USE_VFP3_INSTRUCTIONS))
141 #define ARM_ARCH_DEFAULT "armv8"
142 #elif defined(CAN_USE_ARMV7_INSTRUCTIONS) && defined(CAN_USE_SUDIV) && \
143     defined(CAN_USE_NEON) && defined(CAN_USE_VFP3_INSTRUCTIONS)
144 #define ARM_ARCH_DEFAULT "armv7+sudiv"
145 #elif defined(CAN_USE_ARMV7_INSTRUCTIONS) && defined(CAN_USE_NEON) && \
146     defined(CAN_USE_VFP3_INSTRUCTIONS)
147 #define ARM_ARCH_DEFAULT "armv7"
148 #else
149 #define ARM_ARCH_DEFAULT "armv6"
150 #endif
151 
152 #ifdef V8_OS_WIN
153 # define ENABLE_LOG_COLOUR false
154 #else
155 # define ENABLE_LOG_COLOUR true
156 #endif
157 
158 #define DEFINE_BOOL(nam, def, cmt) FLAG(BOOL, bool, nam, def, cmt)
159 #define DEFINE_BOOL_READONLY(nam, def, cmt) \
160   FLAG_READONLY(BOOL, bool, nam, def, cmt)
161 #define DEFINE_MAYBE_BOOL(nam, cmt) \
162   FLAG(MAYBE_BOOL, MaybeBoolFlag, nam, {false COMMA false}, cmt)
163 #define DEFINE_INT(nam, def, cmt) FLAG(INT, int, nam, def, cmt)
164 #define DEFINE_UINT(nam, def, cmt) FLAG(UINT, unsigned int, nam, def, cmt)
165 #define DEFINE_UINT64(nam, def, cmt) FLAG(UINT64, uint64_t, nam, def, cmt)
166 #define DEFINE_FLOAT(nam, def, cmt) FLAG(FLOAT, double, nam, def, cmt)
167 #define DEFINE_SIZE_T(nam, def, cmt) FLAG(SIZE_T, size_t, nam, def, cmt)
168 #define DEFINE_STRING(nam, def, cmt) FLAG(STRING, const char*, nam, def, cmt)
169 #define DEFINE_ARGS(nam, cmt) \
170   FLAG(ARGS, JSArguments, nam, {0 COMMA nullptr}, cmt)
171 
172 #define DEFINE_ALIAS_BOOL(alias, nam) FLAG_ALIAS(BOOL, bool, alias, nam)
173 #define DEFINE_ALIAS_INT(alias, nam) FLAG_ALIAS(INT, int, alias, nam)
174 #define DEFINE_ALIAS_FLOAT(alias, nam) FLAG_ALIAS(FLOAT, double, alias, nam)
175 #define DEFINE_ALIAS_SIZE_T(alias, nam) FLAG_ALIAS(SIZE_T, size_t, alias, nam)
176 #define DEFINE_ALIAS_STRING(alias, nam) \
177   FLAG_ALIAS(STRING, const char*, alias, nam)
178 #define DEFINE_ALIAS_ARGS(alias, nam) FLAG_ALIAS(ARGS, JSArguments, alias, nam)
179 
180 #ifdef DEBUG
181 #define DEFINE_DEBUG_BOOL DEFINE_BOOL
182 #else
183 #define DEFINE_DEBUG_BOOL DEFINE_BOOL_READONLY
184 #endif
185 
186 //
187 // Flags in all modes.
188 //
189 #define FLAG FLAG_FULL
190 
191 DEFINE_BOOL(experimental_extras, false,
192             "enable code compiled in via v8_experimental_extra_library_files")
193 
194 // Flags for language modes and experimental language features.
195 DEFINE_BOOL(use_strict, false, "enforce strict mode")
196 
197 DEFINE_BOOL(es_staging, false,
198             "enable test-worthy harmony features (for internal use only)")
199 DEFINE_BOOL(harmony, false, "enable all completed harmony features")
200 DEFINE_BOOL(harmony_shipping, true, "enable all shipped harmony features")
201 DEFINE_IMPLICATION(es_staging, harmony)
202 // Enabling import.meta requires to also enable import()
203 DEFINE_IMPLICATION(harmony_import_meta, harmony_dynamic_import)
204 
205 DEFINE_IMPLICATION(harmony_class_fields, harmony_public_fields)
206 DEFINE_IMPLICATION(harmony_class_fields, harmony_static_fields)
207 DEFINE_IMPLICATION(harmony_class_fields, harmony_private_fields)
208 
209 // Update bootstrapper.cc whenever adding a new feature flag.
210 
211 // Features that are still work in progress (behind individual flags).
212 #define HARMONY_INPROGRESS_BASE(V)                                    \
213   V(harmony_do_expressions, "harmony do-expressions")                 \
214   V(harmony_class_fields, "harmony fields in class literals")         \
215   V(harmony_static_fields, "harmony static fields in class literals") \
216   V(harmony_await_optimization, "harmony await taking 1 tick")
217 
218 #ifdef V8_INTL_SUPPORT
219 #define HARMONY_INPROGRESS(V)                    \
220   HARMONY_INPROGRESS_BASE(V)                     \
221   V(harmony_locale, "Intl.Locale")               \
222   V(harmony_intl_list_format, "Intl.ListFormat") \
223   V(harmony_intl_relative_time_format, "Intl.RelativeTimeFormat")
224 #else
225 #define HARMONY_INPROGRESS(V) HARMONY_INPROGRESS_BASE(V)
226 #endif
227 
228 // Features that are complete (but still behind --harmony/es-staging flag).
229 #define HARMONY_STAGED(V)                                                  \
230   V(harmony_public_fields, "harmony public fields in class literals")      \
231   V(harmony_private_fields, "harmony private fields in class literals")    \
232   V(harmony_numeric_separator, "harmony numeric separator between digits") \
233   V(harmony_string_matchall, "harmony String.prototype.matchAll")          \
234   V(harmony_global, "harmony global")
235 
236 // Features that are shipping (turned on by default, but internal flag remains).
237 #define HARMONY_SHIPPING(V)                                              \
238   V(harmony_string_trimming, "harmony String.prototype.trim{Start,End}") \
239   V(harmony_sharedarraybuffer, "harmony sharedarraybuffer")              \
240   V(harmony_function_tostring, "harmony Function.prototype.toString")    \
241   V(harmony_import_meta, "harmony import.meta property")                 \
242   V(harmony_bigint, "harmony arbitrary precision integers")              \
243   V(harmony_dynamic_import, "harmony dynamic import")                    \
244   V(harmony_array_prototype_values, "harmony Array.prototype.values")    \
245   V(harmony_array_flat, "harmony Array.prototype.{flat,flatMap}")        \
246   V(harmony_symbol_description, "harmony Symbol.prototype.description")
247 
248 // Once a shipping feature has proved stable in the wild, it will be dropped
249 // from HARMONY_SHIPPING, all occurrences of the FLAG_ variable are removed,
250 // and associated tests are moved from the harmony directory to the appropriate
251 // esN directory.
252 
253 
254 #define FLAG_INPROGRESS_FEATURES(id, description) \
255   DEFINE_BOOL(id, false, "enable " #description " (in progress)")
256 HARMONY_INPROGRESS(FLAG_INPROGRESS_FEATURES)
257 #undef FLAG_INPROGRESS_FEATURES
258 
259 #define FLAG_STAGED_FEATURES(id, description) \
260   DEFINE_BOOL(id, false, "enable " #description) \
261   DEFINE_IMPLICATION(harmony, id)
262 HARMONY_STAGED(FLAG_STAGED_FEATURES)
263 #undef FLAG_STAGED_FEATURES
264 
265 #define FLAG_SHIPPING_FEATURES(id, description) \
266   DEFINE_BOOL(id, true, "enable " #description) \
267   DEFINE_NEG_NEG_IMPLICATION(harmony_shipping, id)
268 HARMONY_SHIPPING(FLAG_SHIPPING_FEATURES)
269 #undef FLAG_SHIPPING_FEATURES
270 
271 #ifdef V8_INTL_SUPPORT
272 DEFINE_BOOL(icu_timezone_data, true, "get information about timezones from ICU")
273 #endif
274 
275 #ifdef V8_ENABLE_FUTURE
276 #define FUTURE_BOOL true
277 #else
278 #define FUTURE_BOOL false
279 #endif
280 DEFINE_BOOL(future, FUTURE_BOOL,
281             "Implies all staged features that we want to ship in the "
282             "not-too-far future")
283 
284 DEFINE_IMPLICATION(future, write_protect_code_memory)
285 
286 // Flags for experimental implementation features.
287 DEFINE_BOOL(allocation_site_pretenuring, true,
288             "pretenure with allocation sites")
289 DEFINE_BOOL(page_promotion, true, "promote pages based on utilization")
290 DEFINE_INT(page_promotion_threshold, 70,
291            "min percentage of live bytes on a page to enable fast evacuation")
292 DEFINE_BOOL(trace_pretenuring, false,
293             "trace pretenuring decisions of HAllocate instructions")
294 DEFINE_BOOL(trace_pretenuring_statistics, false,
295             "trace allocation site pretenuring statistics")
296 DEFINE_BOOL(track_fields, true, "track fields with only smi values")
297 DEFINE_BOOL(track_double_fields, true, "track fields with double values")
298 DEFINE_BOOL(track_heap_object_fields, true, "track fields with heap values")
299 DEFINE_BOOL(track_computed_fields, true, "track computed boilerplate fields")
300 DEFINE_IMPLICATION(track_double_fields, track_fields)
301 DEFINE_IMPLICATION(track_heap_object_fields, track_fields)
302 DEFINE_IMPLICATION(track_computed_fields, track_fields)
303 DEFINE_BOOL(track_field_types, true, "track field types")
304 DEFINE_IMPLICATION(track_field_types, track_fields)
305 DEFINE_IMPLICATION(track_field_types, track_heap_object_fields)
306 DEFINE_BOOL(trace_block_coverage, false,
307             "trace collected block coverage information")
308 DEFINE_BOOL(feedback_normalization, false,
309             "feed back normalization to constructors")
310 // TODO(jkummerow): This currently adds too much load on the stub cache.
311 DEFINE_BOOL_READONLY(internalize_on_the_fly, true,
312                      "internalize string keys for generic keyed ICs on the fly")
313 
314 // Flags for optimization types.
315 DEFINE_BOOL(optimize_for_size, false,
316             "Enables optimizations which favor memory size over execution "
317             "speed")
318 
319 // Flag for one shot optimiztions.
320 DEFINE_BOOL(enable_one_shot_optimization, true,
321             "Enable size optimizations for the code that will "
322             "only be executed once")
323 
324 DEFINE_VALUE_IMPLICATION(optimize_for_size, max_semi_space_size, 1)
325 
326 // Flags for data representation optimizations
327 DEFINE_BOOL(unbox_double_arrays, true, "automatically unbox arrays of doubles")
328 DEFINE_BOOL_READONLY(string_slices, true, "use string slices")
329 
330 // Flags for Ignition for no-snapshot builds.
331 #undef FLAG
332 #ifndef V8_USE_SNAPSHOT
333 #define FLAG FLAG_FULL
334 #else
335 #define FLAG FLAG_READONLY
336 #endif
337 DEFINE_INT(interrupt_budget, 144 * KB,
338            "interrupt budget which should be used for the profiler counter")
339 #undef FLAG
340 #define FLAG FLAG_FULL
341 
342 // Flags for Ignition.
343 DEFINE_BOOL(ignition_elide_noneffectful_bytecodes, true,
344             "elide bytecodes which won't have any external effect")
345 DEFINE_BOOL(ignition_reo, true, "use ignition register equivalence optimizer")
346 DEFINE_BOOL(ignition_filter_expression_positions, true,
347             "filter expression positions before the bytecode pipeline")
348 DEFINE_BOOL(ignition_share_named_property_feedback, true,
349             "share feedback slots when loading the same named property from "
350             "the same object")
351 DEFINE_BOOL(print_bytecode, false,
352             "print bytecode generated by ignition interpreter")
353 DEFINE_STRING(print_bytecode_filter, "*",
354               "filter for selecting which functions to print bytecode")
355 #ifdef V8_TRACE_IGNITION
356 DEFINE_BOOL(trace_ignition, false,
357             "trace the bytecodes executed by the ignition interpreter")
358 #endif
359 #ifdef V8_TRACE_FEEDBACK_UPDATES
360 DEFINE_BOOL(
361     trace_feedback_updates, false,
362     "trace updates to feedback vectors during ignition interpreter execution.")
363 #endif
364 DEFINE_BOOL(trace_ignition_codegen, false,
365             "trace the codegen of ignition interpreter bytecode handlers")
366 DEFINE_BOOL(trace_ignition_dispatches, false,
367             "traces the dispatches to bytecode handlers by the ignition "
368             "interpreter")
369 DEFINE_STRING(trace_ignition_dispatches_output_file, nullptr,
370               "the file to which the bytecode handler dispatch table is "
371               "written (by default, the table is not written to a file)")
372 
373 DEFINE_BOOL(fast_math, true, "faster (but maybe less accurate) math functions")
374 DEFINE_BOOL(trace_track_allocation_sites, false,
375             "trace the tracking of allocation sites")
376 DEFINE_BOOL(trace_migration, false, "trace object migration")
377 DEFINE_BOOL(trace_generalization, false, "trace map generalization")
378 
379 // Flags for concurrent recompilation.
380 DEFINE_BOOL(concurrent_recompilation, true,
381             "optimizing hot functions asynchronously on a separate thread")
382 DEFINE_BOOL(trace_concurrent_recompilation, false,
383             "track concurrent recompilation")
384 DEFINE_INT(concurrent_recompilation_queue_length, 8,
385            "the length of the concurrent compilation queue")
386 DEFINE_INT(concurrent_recompilation_delay, 0,
387            "artificial compilation delay in ms")
388 DEFINE_BOOL(block_concurrent_recompilation, false,
389             "block queued jobs until released")
390 DEFINE_BOOL(concurrent_compiler_frontend, false,
391             "run optimizing compiler's frontend phases on a separate thread")
392 DEFINE_IMPLICATION(future, concurrent_compiler_frontend)
393 DEFINE_BOOL(strict_heap_broker, false, "fail on incomplete serialization")
394 DEFINE_BOOL(trace_heap_broker, false, "trace the heap broker")
395 
396 // Flags for stress-testing the compiler.
397 DEFINE_INT(stress_runs, 0, "number of stress runs")
398 DEFINE_INT(deopt_every_n_times, 0,
399            "deoptimize every n times a deopt point is passed")
400 DEFINE_BOOL(print_deopt_stress, false, "print number of possible deopt points")
401 
402 // Flags for TurboFan.
403 DEFINE_BOOL(turbo_sp_frame_access, false,
404             "use stack pointer-relative access to frame wherever possible")
405 DEFINE_BOOL(turbo_preprocess_ranges, true,
406             "run pre-register allocation heuristics")
407 DEFINE_STRING(turbo_filter, "*", "optimization filter for TurboFan compiler")
408 DEFINE_BOOL(trace_turbo, false, "trace generated TurboFan IR")
409 DEFINE_STRING(trace_turbo_path, nullptr,
410               "directory to dump generated TurboFan IR to")
411 DEFINE_STRING(trace_turbo_filter, "*",
412               "filter for tracing turbofan compilation")
413 DEFINE_BOOL(trace_turbo_graph, false, "trace generated TurboFan graphs")
414 DEFINE_BOOL(trace_turbo_scheduled, false, "trace TurboFan IR with schedule")
415 DEFINE_IMPLICATION(trace_turbo_scheduled, trace_turbo_graph)
416 DEFINE_STRING(trace_turbo_cfg_file, nullptr,
417               "trace turbo cfg graph (for C1 visualizer) to a given file name")
418 DEFINE_BOOL(trace_turbo_types, true, "trace TurboFan's types")
419 DEFINE_BOOL(trace_turbo_scheduler, false, "trace TurboFan's scheduler")
420 DEFINE_BOOL(trace_turbo_reduction, false, "trace TurboFan's various reducers")
421 DEFINE_BOOL(trace_turbo_trimming, false, "trace TurboFan's graph trimmer")
422 DEFINE_BOOL(trace_turbo_jt, false, "trace TurboFan's jump threading")
423 DEFINE_BOOL(trace_turbo_ceq, false, "trace TurboFan's control equivalence")
424 DEFINE_BOOL(trace_turbo_loop, false, "trace TurboFan's loop optimizations")
425 DEFINE_BOOL(trace_alloc, false, "trace register allocator")
426 DEFINE_BOOL(trace_all_uses, false, "trace all use positions")
427 DEFINE_BOOL(trace_representation, false, "trace representation types")
428 DEFINE_BOOL(turbo_verify, DEBUG_BOOL, "verify TurboFan graphs at each phase")
429 DEFINE_STRING(turbo_verify_machine_graph, nullptr,
430               "verify TurboFan machine graph before instruction selection")
431 #ifdef ENABLE_VERIFY_CSA
432 DEFINE_BOOL(verify_csa, DEBUG_BOOL,
433             "verify TurboFan machine graph of code stubs")
434 #else
435 // Define the flag as read-only-false so that code still compiles even in the
436 // non-ENABLE_VERIFY_CSA configuration.
437 DEFINE_BOOL_READONLY(verify_csa, false,
438                      "verify TurboFan machine graph of code stubs")
439 #endif
440 DEFINE_BOOL(trace_verify_csa, false, "trace code stubs verification")
441 DEFINE_STRING(csa_trap_on_node, nullptr,
442               "trigger break point when a node with given id is created in "
443               "given stub. The format is: StubName,NodeId")
444 DEFINE_BOOL_READONLY(fixed_array_bounds_checks, DEBUG_BOOL,
445                      "enable FixedArray bounds checks")
446 DEFINE_BOOL(turbo_stats, false, "print TurboFan statistics")
447 DEFINE_BOOL(turbo_stats_nvp, false,
448             "print TurboFan statistics in machine-readable format")
449 DEFINE_BOOL(turbo_stats_wasm, false,
450             "print TurboFan statistics of wasm compilations")
451 DEFINE_BOOL(turbo_splitting, true, "split nodes during scheduling in TurboFan")
452 DEFINE_BOOL(function_context_specialization, false,
453             "enable function context specialization in TurboFan")
454 DEFINE_BOOL(turbo_inlining, true, "enable inlining in TurboFan")
455 DEFINE_INT(max_inlined_bytecode_size, 500,
456            "maximum size of bytecode for a single inlining")
457 DEFINE_INT(max_inlined_bytecode_size_cumulative, 1000,
458            "maximum cumulative size of bytecode considered for inlining")
459 DEFINE_INT(max_inlined_bytecode_size_absolute, 5000,
460            "maximum cumulative size of bytecode considered for inlining")
461 DEFINE_FLOAT(reserve_inline_budget_scale_factor, 1.2,
462              "maximum cumulative size of bytecode considered for inlining")
463 DEFINE_INT(max_inlined_bytecode_size_small, 30,
464            "maximum size of bytecode considered for small function inlining")
465 DEFINE_FLOAT(min_inlining_frequency, 0.15, "minimum frequency for inlining")
466 DEFINE_BOOL(polymorphic_inlining, true, "polymorphic inlining")
467 DEFINE_BOOL(stress_inline, false,
468             "set high thresholds for inlining to inline as much as possible")
469 DEFINE_VALUE_IMPLICATION(stress_inline, max_inlined_bytecode_size, 999999)
470 DEFINE_VALUE_IMPLICATION(stress_inline, max_inlined_bytecode_size_cumulative,
471                          999999)
472 DEFINE_VALUE_IMPLICATION(stress_inline, max_inlined_bytecode_size_absolute,
473                          999999)
474 DEFINE_VALUE_IMPLICATION(stress_inline, min_inlining_frequency, 0)
475 DEFINE_VALUE_IMPLICATION(stress_inline, polymorphic_inlining, true)
476 DEFINE_BOOL(trace_turbo_inlining, false, "trace TurboFan inlining")
477 DEFINE_BOOL(inline_accessors, true, "inline JavaScript accessors")
478 DEFINE_BOOL(inline_into_try, true, "inline into try blocks")
479 DEFINE_BOOL(turbo_inline_array_builtins, true,
480             "inline array builtins in TurboFan code")
481 DEFINE_BOOL(use_osr, true, "use on-stack replacement")
482 DEFINE_BOOL(trace_osr, false, "trace on-stack replacement")
483 DEFINE_BOOL(analyze_environment_liveness, true,
484             "analyze liveness of environment slots and zap dead values")
485 DEFINE_BOOL(trace_environment_liveness, false,
486             "trace liveness of local variable slots")
487 DEFINE_BOOL(turbo_load_elimination, true, "enable load elimination in TurboFan")
488 DEFINE_BOOL(trace_turbo_load_elimination, false,
489             "trace TurboFan load elimination")
490 DEFINE_BOOL(turbo_profiling, false, "enable profiling in TurboFan")
491 DEFINE_BOOL(turbo_verify_allocation, DEBUG_BOOL,
492             "verify register allocation in TurboFan")
493 DEFINE_BOOL(turbo_move_optimization, true, "optimize gap moves in TurboFan")
494 DEFINE_BOOL(turbo_jt, true, "enable jump threading in TurboFan")
495 DEFINE_BOOL(turbo_loop_peeling, true, "Turbofan loop peeling")
496 DEFINE_BOOL(turbo_loop_variable, true, "Turbofan loop variable optimization")
497 DEFINE_BOOL(turbo_cf_optimization, true, "optimize control flow in TurboFan")
498 DEFINE_BOOL(turbo_escape, true, "enable escape analysis")
499 DEFINE_BOOL(turbo_allocation_folding, true, "Turbofan allocation folding")
500 DEFINE_BOOL(turbo_instruction_scheduling, false,
501             "enable instruction scheduling in TurboFan")
502 DEFINE_BOOL(turbo_stress_instruction_scheduling, false,
503             "randomly schedule instructions to stress dependency tracking")
504 DEFINE_BOOL(turbo_store_elimination, true,
505             "enable store-store elimination in TurboFan")
506 DEFINE_BOOL(trace_store_elimination, false, "trace store elimination")
507 DEFINE_BOOL(turbo_rewrite_far_jumps, true,
508             "rewrite far to near jumps (ia32,x64)")
509 DEFINE_BOOL(experimental_inline_promise_constructor, true,
510             "inline the Promise constructor in TurboFan")
511 
512 #ifdef DISABLE_UNTRUSTED_CODE_MITIGATIONS
513 #define V8_DEFAULT_UNTRUSTED_CODE_MITIGATIONS false
514 #else
515 #define V8_DEFAULT_UNTRUSTED_CODE_MITIGATIONS true
516 #endif
517 DEFINE_BOOL(untrusted_code_mitigations, V8_DEFAULT_UNTRUSTED_CODE_MITIGATIONS,
518             "Enable mitigations for executing untrusted code")
519 #undef V8_DEFAULT_UNTRUSTED_CODE_MITIGATIONS
520 
521 DEFINE_BOOL(branch_load_poisoning, false, "Mask loads with branch conditions.")
522 DEFINE_IMPLICATION(future, branch_load_poisoning)
523 
524 // Flags to help platform porters
525 DEFINE_BOOL(minimal, false,
526             "simplifies execution model to make porting "
527             "easier (e.g. always use Ignition, never optimize)")
528 DEFINE_NEG_IMPLICATION(minimal, opt)
529 DEFINE_NEG_IMPLICATION(minimal, use_ic)
530 
531 // Flags for native WebAssembly.
532 DEFINE_BOOL(expose_wasm, true, "expose wasm interface to JavaScript")
533 DEFINE_BOOL(assume_asmjs_origin, false,
534             "force wasm decoder to assume input is internal asm-wasm format")
535 DEFINE_BOOL(wasm_disable_structured_cloning, false,
536             "disable wasm structured cloning")
537 DEFINE_INT(wasm_num_compilation_tasks, 10,
538            "number of parallel compilation tasks for wasm")
539 DEFINE_DEBUG_BOOL(wasm_trace_native_heap, false,
540                   "trace wasm native heap events")
541 DEFINE_BOOL(wasm_write_protect_code_memory, false,
542             "write protect code memory on the wasm native heap")
543 DEFINE_BOOL(wasm_trace_serialization, false,
544             "trace serialization/deserialization")
545 DEFINE_BOOL(wasm_async_compilation, true,
546             "enable actual asynchronous compilation for WebAssembly.compile")
547 DEFINE_BOOL(wasm_test_streaming, false,
548             "use streaming compilation instead of async compilation for tests")
549 DEFINE_UINT(wasm_max_mem_pages, v8::internal::wasm::kV8MaxWasmMemoryPages,
550             "maximum number of 64KiB memory pages of a wasm instance")
551 DEFINE_UINT(wasm_max_table_size, v8::internal::wasm::kV8MaxWasmTableSize,
552             "maximum table size of a wasm instance")
553 // Enable Liftoff by default on ia32 and x64. More architectures will follow
554 // once they are implemented and sufficiently tested.
555 #if V8_TARGET_ARCH_IA32 || V8_TARGET_ARCH_X64
556 DEFINE_BOOL(
557     wasm_tier_up, true,
558     "enable wasm baseline compilation and tier up to the optimizing compiler")
559 #else
560 DEFINE_BOOL(
561     wasm_tier_up, false,
562     "enable wasm baseline compilation and tier up to the optimizing compiler")
563 DEFINE_IMPLICATION(future, wasm_tier_up)
564 #endif
565 DEFINE_IMPLICATION(wasm_tier_up, liftoff)
566 DEFINE_DEBUG_BOOL(trace_wasm_decoder, false, "trace decoding of wasm code")
567 DEFINE_DEBUG_BOOL(trace_wasm_decode_time, false,
568                   "trace decoding time of wasm code")
569 DEFINE_DEBUG_BOOL(trace_wasm_compiler, false, "trace compiling of wasm code")
570 DEFINE_DEBUG_BOOL(trace_wasm_interpreter, false,
571                   "trace interpretation of wasm code")
572 DEFINE_DEBUG_BOOL(trace_wasm_streaming, false,
573                   "trace streaming compilation of wasm code")
574 DEFINE_INT(trace_wasm_ast_start, 0,
575            "start function for wasm AST trace (inclusive)")
576 DEFINE_INT(trace_wasm_ast_end, 0, "end function for wasm AST trace (exclusive)")
577 DEFINE_BOOL(liftoff, false,
578             "enable Liftoff, the baseline compiler for WebAssembly")
579 DEFINE_DEBUG_BOOL(trace_liftoff, false,
580                   "trace Liftoff, the baseline compiler for WebAssembly")
581 DEFINE_DEBUG_BOOL(wasm_break_on_decoder_error, false,
582                   "debug break when wasm decoder encounters an error")
583 DEFINE_BOOL(wasm_trace_memory, false,
584             "print all memory updates performed in wasm code")
585 // Fuzzers use {wasm_tier_mask_for_testing} together with {liftoff} and
586 // {no_wasm_tier_up} to force some functions to be compiled with Turbofan.
587 DEFINE_INT(wasm_tier_mask_for_testing, 0,
588            "bitmask of functions to compile with TurboFan instead of Liftoff")
589 
590 DEFINE_BOOL(validate_asm, true, "validate asm.js modules before compiling")
591 DEFINE_BOOL(suppress_asm_messages, false,
592             "don't emit asm.js related messages (for golden file testing)")
593 DEFINE_BOOL(trace_asm_time, false, "log asm.js timing info to the console")
594 DEFINE_BOOL(trace_asm_scanner, false,
595             "log tokens encountered by asm.js scanner")
596 DEFINE_BOOL(trace_asm_parser, false, "verbose logging of asm.js parse failures")
597 DEFINE_BOOL(stress_validate_asm, false, "try to validate everything as asm.js")
598 
599 DEFINE_DEBUG_BOOL(dump_wasm_module, false, "dump wasm module bytes")
600 DEFINE_STRING(dump_wasm_module_path, nullptr,
601               "directory to dump wasm modules to")
602 
603 // Declare command-line flags for WASM features. Warning: avoid using these
604 // flags directly in the implementation. Instead accept wasm::WasmFeatures
605 // for configurability.
606 #include "src/wasm/wasm-feature-flags.h"
607 
608 #define SPACE
609 #define DECL_WASM_FLAG(feat, desc, val)      \
610   DEFINE_BOOL(experimental_wasm_##feat, val, \
611               "enable prototype " desc " for wasm")
612 FOREACH_WASM_FEATURE_FLAG(DECL_WASM_FLAG, SPACE)
613 #undef DECL_WASM_FLAG
614 #undef SPACE
615 
616 DEFINE_BOOL(wasm_opt, false, "enable wasm optimization")
617 DEFINE_BOOL(wasm_no_bounds_checks, false,
618             "disable bounds checks (performance testing only)")
619 DEFINE_BOOL(wasm_no_stack_checks, false,
620             "disable stack checks (performance testing only)")
621 
622 DEFINE_BOOL(wasm_shared_engine, true,
623             "shares one wasm engine between all isolates within a process")
624 DEFINE_IMPLICATION(future, wasm_shared_engine)
625 DEFINE_BOOL(wasm_shared_code, true,
626             "shares code underlying a wasm module when it is transferred")
627 DEFINE_IMPLICATION(future, wasm_shared_code)
628 DEFINE_BOOL(wasm_trap_handler, true,
629             "use signal handlers to catch out of bounds memory access in wasm"
630             " (currently Linux x86_64 only)")
631 DEFINE_BOOL(wasm_trap_handler_fallback, false,
632             "Use bounds checks if guarded memory is not available")
633 DEFINE_BOOL(wasm_fuzzer_gen_test, false,
634             "Generate a test case when running a wasm fuzzer")
635 DEFINE_IMPLICATION(wasm_fuzzer_gen_test, single_threaded)
636 DEFINE_BOOL(print_wasm_code, false, "Print WebAssembly code")
637 DEFINE_BOOL(wasm_interpret_all, false,
638             "Execute all wasm code in the wasm interpreter")
639 DEFINE_BOOL(asm_wasm_lazy_compilation, false,
640             "enable lazy compilation for asm-wasm modules")
641 DEFINE_IMPLICATION(validate_asm, asm_wasm_lazy_compilation)
642 DEFINE_BOOL(wasm_lazy_compilation, false,
643             "enable lazy compilation for all wasm modules")
644 DEFINE_DEBUG_BOOL(trace_wasm_lazy_compilation, false,
645                   "trace lazy compilation of wasm functions")
646 // wasm-interpret-all resets {asm-,}wasm-lazy-compilation.
647 DEFINE_NEG_IMPLICATION(wasm_interpret_all, asm_wasm_lazy_compilation)
648 DEFINE_NEG_IMPLICATION(wasm_interpret_all, wasm_lazy_compilation)
649 
650 // Profiler flags.
651 DEFINE_INT(frame_count, 1, "number of stack frames inspected by the profiler")
652 DEFINE_INT(type_info_threshold, 25,
653            "percentage of ICs that must have type info to allow optimization")
654 
655 DEFINE_INT(stress_sampling_allocation_profiler, 0,
656            "Enables sampling allocation profiler with X as a sample interval")
657 
658 // Garbage collections flags.
659 DEFINE_SIZE_T(min_semi_space_size, 0,
660               "min size of a semi-space (in MBytes), the new space consists of "
661               "two semi-spaces")
662 DEFINE_SIZE_T(max_semi_space_size, 0,
663               "max size of a semi-space (in MBytes), the new space consists of "
664               "two semi-spaces")
665 DEFINE_INT(semi_space_growth_factor, 2, "factor by which to grow the new space")
666 DEFINE_BOOL(experimental_new_space_growth_heuristic, false,
667             "Grow the new space based on the percentage of survivors instead "
668             "of their absolute value.")
669 DEFINE_SIZE_T(max_old_space_size, 0, "max size of the old space (in Mbytes)")
670 DEFINE_SIZE_T(initial_old_space_size, 0, "initial old space size (in Mbytes)")
671 DEFINE_BOOL(gc_global, false, "always perform global GCs")
672 DEFINE_INT(random_gc_interval, 0,
673            "Collect garbage after random(0, X) allocations. It overrides "
674            "gc_interval.")
675 DEFINE_INT(gc_interval, -1, "garbage collect after <n> allocations")
676 DEFINE_INT(retain_maps_for_n_gc, 2,
677            "keeps maps alive for <n> old space garbage collections")
678 DEFINE_BOOL(trace_gc, false,
679             "print one trace line following each garbage collection")
680 DEFINE_BOOL(trace_gc_nvp, false,
681             "print one detailed trace line in name=value format "
682             "after each garbage collection")
683 DEFINE_BOOL(trace_gc_ignore_scavenger, false,
684             "do not print trace line after scavenger collection")
685 DEFINE_BOOL(trace_idle_notification, false,
686             "print one trace line following each idle notification")
687 DEFINE_BOOL(trace_idle_notification_verbose, false,
688             "prints the heap state used by the idle notification")
689 DEFINE_BOOL(trace_gc_verbose, false,
690             "print more details following each garbage collection")
691 DEFINE_INT(trace_allocation_stack_interval, -1,
692            "print stack trace after <n> free-list allocations")
693 DEFINE_INT(trace_duplicate_threshold_kb, 0,
694            "print duplicate objects in the heap if their size is more than "
695            "given threshold")
696 DEFINE_BOOL(trace_fragmentation, false, "report fragmentation for old space")
697 DEFINE_BOOL(trace_fragmentation_verbose, false,
698             "report fragmentation for old space (detailed)")
699 DEFINE_BOOL(trace_evacuation, false, "report evacuation statistics")
700 DEFINE_BOOL(trace_mutator_utilization, false,
701             "print mutator utilization, allocation speed, gc speed")
702 DEFINE_BOOL(incremental_marking, true, "use incremental marking")
703 DEFINE_BOOL(incremental_marking_wrappers, true,
704             "use incremental marking for marking wrappers")
705 DEFINE_BOOL(trace_unmapper, false, "Trace the unmapping")
706 DEFINE_BOOL(parallel_scavenge, true, "parallel scavenge")
707 DEFINE_BOOL(trace_parallel_scavenge, false, "trace parallel scavenge")
708 #if defined(V8_TARGET_ARCH_ARM) || defined(V8_TARGET_ARCH_ARM64)
709 #define V8_WRITE_PROTECT_CODE_MEMORY_BOOL false
710 #else
711 #define V8_WRITE_PROTECT_CODE_MEMORY_BOOL true
712 #endif
713 DEFINE_BOOL(write_protect_code_memory, V8_WRITE_PROTECT_CODE_MEMORY_BOOL,
714             "write protect code memory")
715 #ifdef V8_CONCURRENT_MARKING
716 #define V8_CONCURRENT_MARKING_BOOL true
717 #else
718 #define V8_CONCURRENT_MARKING_BOOL false
719 #endif
720 DEFINE_BOOL(concurrent_marking, V8_CONCURRENT_MARKING_BOOL,
721             "use concurrent marking")
722 DEFINE_BOOL(parallel_marking, true, "use parallel marking in atomic pause")
723 DEFINE_IMPLICATION(parallel_marking, concurrent_marking)
724 DEFINE_INT(ephemeron_fixpoint_iterations, 10,
725            "number of fixpoint iterations it takes to switch to linear "
726            "ephemeron algorithm")
727 DEFINE_BOOL(trace_concurrent_marking, false, "trace concurrent marking")
728 DEFINE_BOOL(black_allocation, true, "use black allocation")
729 DEFINE_BOOL(concurrent_store_buffer, true,
730             "use concurrent store buffer processing")
731 DEFINE_BOOL(concurrent_sweeping, true, "use concurrent sweeping")
732 DEFINE_BOOL(parallel_compaction, true, "use parallel compaction")
733 DEFINE_BOOL(parallel_pointer_update, true,
734             "use parallel pointer update during compaction")
735 DEFINE_BOOL(detect_ineffective_gcs_near_heap_limit, true,
736             "trigger out-of-memory failure to avoid GC storm near heap limit")
737 DEFINE_BOOL(trace_incremental_marking, false,
738             "trace progress of the incremental marking")
739 DEFINE_BOOL(trace_stress_marking, false, "trace stress marking progress")
740 DEFINE_BOOL(trace_stress_scavenge, false, "trace stress scavenge progress")
741 DEFINE_BOOL(track_gc_object_stats, false,
742             "track object counts and memory usage")
743 DEFINE_BOOL(trace_gc_object_stats, false,
744             "trace object counts and memory usage")
745 DEFINE_BOOL(trace_zone_stats, false, "trace zone memory usage")
746 DEFINE_BOOL(track_retaining_path, false,
747             "enable support for tracking retaining path")
748 DEFINE_BOOL(concurrent_array_buffer_freeing, true,
749             "free array buffer allocations on a background thread")
750 DEFINE_INT(gc_stats, 0, "Used by tracing internally to enable gc statistics")
751 DEFINE_IMPLICATION(trace_gc_object_stats, track_gc_object_stats)
752 DEFINE_VALUE_IMPLICATION(track_gc_object_stats, gc_stats, 1)
753 DEFINE_VALUE_IMPLICATION(trace_gc_object_stats, gc_stats, 1)
754 DEFINE_NEG_IMPLICATION(trace_gc_object_stats, incremental_marking)
755 DEFINE_NEG_IMPLICATION(track_retaining_path, incremental_marking)
756 DEFINE_NEG_IMPLICATION(track_retaining_path, parallel_marking)
757 DEFINE_NEG_IMPLICATION(track_retaining_path, concurrent_marking)
758 DEFINE_BOOL(track_detached_contexts, true,
759             "track native contexts that are expected to be garbage collected")
760 DEFINE_BOOL(trace_detached_contexts, false,
761             "trace native contexts that are expected to be garbage collected")
762 DEFINE_IMPLICATION(trace_detached_contexts, track_detached_contexts)
763 #ifdef VERIFY_HEAP
764 DEFINE_BOOL(verify_heap, false, "verify heap pointers before and after GC")
765 DEFINE_BOOL(verify_heap_skip_remembered_set, false,
766             "disable remembered set verification")
767 #endif
768 DEFINE_BOOL(move_object_start, true, "enable moving of object starts")
769 DEFINE_BOOL(memory_reducer, true, "use memory reducer")
770 DEFINE_INT(heap_growing_percent, 0,
771            "specifies heap growing factor as (1 + heap_growing_percent/100)")
772 DEFINE_INT(v8_os_page_size, 0, "override OS page size (in KBytes)")
773 DEFINE_BOOL(always_compact, false, "Perform compaction on every full GC")
774 DEFINE_BOOL(never_compact, false,
775             "Never perform compaction on full GC - testing only")
776 DEFINE_BOOL(compact_code_space, true, "Compact code space on full collections")
777 DEFINE_BOOL(use_marking_progress_bar, true,
778             "Use a progress bar to scan large objects in increments when "
779             "incremental marking is active.")
780 DEFINE_BOOL(force_marking_deque_overflows, false,
781             "force overflows of marking deque by reducing it's size "
782             "to 64 words")
783 DEFINE_BOOL(stress_compaction, false,
784             "stress the GC compactor to flush out bugs (implies "
785             "--force_marking_deque_overflows)")
786 DEFINE_BOOL(stress_compaction_random, false,
787             "Stress GC compaction by selecting random percent of pages as "
788             "evacuation candidates. It overrides stress_compaction.")
789 DEFINE_BOOL(stress_incremental_marking, false,
790             "force incremental marking for small heaps and run it more often")
791 
792 DEFINE_BOOL(fuzzer_gc_analysis, false,
793             "prints number of allocations and enables analysis mode for gc "
794             "fuzz testing, e.g. --stress-marking, --stress-scavenge")
795 DEFINE_INT(stress_marking, 0,
796            "force marking at random points between 0 and X (inclusive) percent "
797            "of the regular marking start limit")
798 DEFINE_INT(stress_scavenge, 0,
799            "force scavenge at random points between 0 and X (inclusive) "
800            "percent of the new space capacity")
801 DEFINE_IMPLICATION(fuzzer_gc_analysis, stress_marking)
802 DEFINE_IMPLICATION(fuzzer_gc_analysis, stress_scavenge)
803 
804 DEFINE_BOOL(disable_abortjs, false, "disables AbortJS runtime function")
805 
806 DEFINE_BOOL(manual_evacuation_candidates_selection, false,
807             "Test mode only flag. It allows an unit test to select evacuation "
808             "candidates pages (requires --stress_compaction).")
809 DEFINE_BOOL(fast_promotion_new_space, false,
810             "fast promote new space on high survival rates")
811 
812 DEFINE_BOOL(clear_free_memory, false, "initialize free memory with 0")
813 
814 DEFINE_BOOL(young_generation_large_objects, false,
815             "allocates large objects by default in the young generation large "
816             "object space")
817 
818 // assembler-ia32.cc / assembler-arm.cc / assembler-x64.cc
819 DEFINE_BOOL(debug_code, DEBUG_BOOL,
820             "generate extra code (assertions) for debugging")
821 DEFINE_BOOL(code_comments, false,
822             "emit comments in code disassembly; for more readable source "
823             "positions you should add --no-concurrent_recompilation")
824 DEFINE_BOOL(enable_sse3, true, "enable use of SSE3 instructions if available")
825 DEFINE_BOOL(enable_ssse3, true, "enable use of SSSE3 instructions if available")
826 DEFINE_BOOL(enable_sse4_1, true,
827             "enable use of SSE4.1 instructions if available")
828 DEFINE_BOOL(enable_sahf, true,
829             "enable use of SAHF instruction if available (X64 only)")
830 DEFINE_BOOL(enable_avx, true, "enable use of AVX instructions if available")
831 DEFINE_BOOL(enable_fma3, true, "enable use of FMA3 instructions if available")
832 DEFINE_BOOL(enable_bmi1, true, "enable use of BMI1 instructions if available")
833 DEFINE_BOOL(enable_bmi2, true, "enable use of BMI2 instructions if available")
834 DEFINE_BOOL(enable_lzcnt, true, "enable use of LZCNT instruction if available")
835 DEFINE_BOOL(enable_popcnt, true,
836             "enable use of POPCNT instruction if available")
837 DEFINE_STRING(arm_arch, ARM_ARCH_DEFAULT,
838               "generate instructions for the selected ARM architecture if "
839               "available: armv6, armv7, armv7+sudiv or armv8")
840 DEFINE_BOOL(force_long_branches, false,
841             "force all emitted branches to be in long mode (MIPS/PPC only)")
842 DEFINE_STRING(mcpu, "auto", "enable optimization for specific cpu")
843 DEFINE_BOOL(partial_constant_pool, true,
844             "enable use of partial constant pools (X64 only)")
845 
846 // Deprecated ARM flags (replaced by arm_arch).
847 DEFINE_MAYBE_BOOL(enable_armv7, "deprecated (use --arm_arch instead)")
848 DEFINE_MAYBE_BOOL(enable_vfp3, "deprecated (use --arm_arch instead)")
849 DEFINE_MAYBE_BOOL(enable_32dregs, "deprecated (use --arm_arch instead)")
850 DEFINE_MAYBE_BOOL(enable_neon, "deprecated (use --arm_arch instead)")
851 DEFINE_MAYBE_BOOL(enable_sudiv, "deprecated (use --arm_arch instead)")
852 DEFINE_MAYBE_BOOL(enable_armv8, "deprecated (use --arm_arch instead)")
853 
854 // regexp-macro-assembler-*.cc
855 DEFINE_BOOL(enable_regexp_unaligned_accesses, true,
856             "enable unaligned accesses for the regexp engine")
857 
858 // api.cc
859 DEFINE_BOOL(script_streaming, true, "enable parsing on background")
860 DEFINE_BOOL(disable_old_api_accessors, false,
861             "Disable old-style API accessors whose setters trigger through the "
862             "prototype chain")
863 
864 // bootstrapper.cc
865 DEFINE_STRING(expose_natives_as, nullptr, "expose natives in global object")
866 DEFINE_BOOL(expose_free_buffer, false, "expose freeBuffer extension")
867 DEFINE_BOOL(expose_gc, false, "expose gc extension")
868 DEFINE_STRING(expose_gc_as, nullptr,
869               "expose gc extension under the specified name")
870 DEFINE_IMPLICATION(expose_gc_as, expose_gc)
871 DEFINE_BOOL(expose_externalize_string, false,
872             "expose externalize string extension")
873 DEFINE_BOOL(expose_trigger_failure, false, "expose trigger-failure extension")
874 DEFINE_INT(stack_trace_limit, 10, "number of stack frames to capture")
875 DEFINE_BOOL(builtins_in_stack_traces, false,
876             "show built-in functions in stack traces")
877 DEFINE_BOOL(enable_experimental_builtins, false,
878             "enable new csa-based experimental builtins")
879 DEFINE_BOOL(disallow_code_generation_from_strings, false,
880             "disallow eval and friends")
881 DEFINE_BOOL(expose_async_hooks, false, "expose async_hooks object")
882 
883 // builtins.cc
884 DEFINE_BOOL(allow_unsafe_function_constructor, false,
885             "allow invoking the function constructor without security checks")
886 DEFINE_BOOL(force_slow_path, false, "always take the slow path for builtins")
887 
888 // builtins-ia32.cc
889 DEFINE_BOOL(inline_new, true, "use fast inline allocation")
890 
891 // codegen-ia32.cc / codegen-arm.cc
892 DEFINE_BOOL(trace, false, "trace function calls")
893 
894 // codegen.cc
895 DEFINE_BOOL(lazy, true, "use lazy compilation")
896 DEFINE_BOOL(trace_opt, false, "trace lazy optimization")
897 DEFINE_BOOL(trace_opt_verbose, false, "extra verbose compilation tracing")
898 DEFINE_IMPLICATION(trace_opt_verbose, trace_opt)
899 DEFINE_BOOL(trace_opt_stats, false, "trace lazy optimization statistics")
900 DEFINE_BOOL(trace_deopt, false, "trace optimize function deoptimization")
901 DEFINE_BOOL(trace_file_names, false,
902             "include file names in trace-opt/trace-deopt output")
903 DEFINE_BOOL(trace_interrupts, false, "trace interrupts when they are handled")
904 DEFINE_BOOL(opt, true, "use adaptive optimizations")
905 DEFINE_BOOL(always_opt, false, "always try to optimize functions")
906 DEFINE_BOOL(always_osr, false, "always try to OSR functions")
907 DEFINE_BOOL(prepare_always_opt, false, "prepare for turning on always opt")
908 
909 DEFINE_BOOL(trace_serializer, false, "print code serializer trace")
910 #ifdef DEBUG
911 DEFINE_BOOL(external_reference_stats, false,
912             "print statistics on external references used during serialization")
913 #endif  // DEBUG
914 
915 // compilation-cache.cc
916 DEFINE_BOOL(compilation_cache, true, "enable compilation cache")
917 
918 DEFINE_BOOL(cache_prototype_transitions, true, "cache prototype transitions")
919 
920 // compiler-dispatcher.cc
921 DEFINE_BOOL(compiler_dispatcher, false, "enable compiler dispatcher")
922 DEFINE_BOOL(trace_compiler_dispatcher, false,
923             "trace compiler dispatcher activity")
924 
925 // compiler-dispatcher-job.cc
926 DEFINE_BOOL(
927     trace_compiler_dispatcher_jobs, false,
928     "trace progress of individual jobs managed by the compiler dispatcher")
929 
930 // cpu-profiler.cc
931 DEFINE_INT(cpu_profiler_sampling_interval, 1000,
932            "CPU profiler sampling interval in microseconds")
933 
934 // Array abuse tracing
935 DEFINE_BOOL(trace_js_array_abuse, false,
936             "trace out-of-bounds accesses to JS arrays")
937 DEFINE_BOOL(trace_external_array_abuse, false,
938             "trace out-of-bounds-accesses to external arrays")
939 DEFINE_BOOL(trace_array_abuse, false,
940             "trace out-of-bounds accesses to all arrays")
941 DEFINE_IMPLICATION(trace_array_abuse, trace_js_array_abuse)
942 DEFINE_IMPLICATION(trace_array_abuse, trace_external_array_abuse)
943 
944 // debugger
945 DEFINE_BOOL(
946     trace_side_effect_free_debug_evaluate, false,
947     "print debug messages for side-effect-free debug-evaluate for testing")
948 DEFINE_BOOL(hard_abort, true, "abort by crashing")
949 
950 // inspector
951 DEFINE_BOOL(expose_inspector_scripts, false,
952             "expose injected-script-source.js for debugging")
953 
954 // execution.cc
955 DEFINE_INT(stack_size, V8_DEFAULT_STACK_SIZE_KB,
956            "default size of stack region v8 is allowed to use (in kBytes)")
957 
958 // frames.cc
959 DEFINE_INT(max_stack_trace_source_length, 300,
960            "maximum length of function source code printed in a stack trace.")
961 
962 // execution.cc, messages.cc
963 DEFINE_BOOL(clear_exceptions_on_js_entry, false,
964             "clear pending exceptions when entering JavaScript")
965 
966 // counters.cc
967 DEFINE_INT(histogram_interval, 600000,
968            "time interval in ms for aggregating memory histograms")
969 
970 // heap-snapshot-generator.cc
971 DEFINE_BOOL(heap_profiler_trace_objects, false,
972             "Dump heap object allocations/movements/size_updates")
973 DEFINE_BOOL(heap_profiler_use_embedder_graph, true,
974             "Use the new EmbedderGraph API to get embedder nodes")
975 DEFINE_INT(heap_snapshot_string_limit, 1024,
976            "truncate strings to this length in the heap snapshot")
977 
978 // sampling-heap-profiler.cc
979 DEFINE_BOOL(sampling_heap_profiler_suppress_randomness, false,
980             "Use constant sample intervals to eliminate test flakiness")
981 
982 // v8.cc
983 DEFINE_BOOL(use_idle_notification, true,
984             "Use idle notification to reduce memory footprint.")
985 // ic.cc
986 DEFINE_BOOL(use_ic, true, "use inline caching")
987 DEFINE_BOOL(trace_ic, false,
988             "trace inline cache state transitions for tools/ic-processor")
989 DEFINE_IMPLICATION(trace_ic, log_code)
990 DEFINE_INT(ic_stats, 0, "inline cache state transitions statistics")
991 DEFINE_VALUE_IMPLICATION(trace_ic, ic_stats, 1)
992 DEFINE_BOOL_READONLY(track_constant_fields, false,
993                      "enable constant field tracking")
994 DEFINE_BOOL_READONLY(modify_map_inplace, false, "enable in-place map updates")
995 
996 // macro-assembler-ia32.cc
997 DEFINE_BOOL(native_code_counters, false,
998             "generate extra code for manipulating stats counters")
999 
1000 // objects.cc
1001 DEFINE_BOOL(thin_strings, true, "Enable ThinString support")
1002 DEFINE_BOOL(trace_prototype_users, false,
1003             "Trace updates to prototype user tracking")
1004 DEFINE_BOOL(use_verbose_printer, true, "allows verbose printing")
1005 DEFINE_BOOL(trace_for_in_enumerate, false, "Trace for-in enumerate slow-paths")
1006 DEFINE_BOOL(trace_maps, false, "trace map creation")
1007 DEFINE_BOOL(trace_maps_details, true, "also log map details")
1008 DEFINE_IMPLICATION(trace_maps, log_code)
1009 
1010 // parser.cc
1011 DEFINE_BOOL(allow_natives_syntax, false, "allow natives syntax")
1012 DEFINE_BOOL(lazy_inner_functions, true, "enable lazy parsing inner functions")
1013 DEFINE_BOOL(aggressive_lazy_inner_functions, false,
1014             "even lazier inner function parsing")
1015 DEFINE_IMPLICATION(aggressive_lazy_inner_functions, lazy_inner_functions)
1016 DEFINE_BOOL(preparser_scope_analysis, true,
1017             "perform scope analysis for preparsed inner functions")
1018 DEFINE_IMPLICATION(preparser_scope_analysis, aggressive_lazy_inner_functions)
1019 
1020 // simulator-arm.cc, simulator-arm64.cc and simulator-mips.cc
1021 DEFINE_BOOL(trace_sim, false, "Trace simulator execution")
1022 DEFINE_BOOL(debug_sim, false, "Enable debugging the simulator")
1023 DEFINE_BOOL(check_icache, false,
1024             "Check icache flushes in ARM and MIPS simulator")
1025 DEFINE_INT(stop_sim_at, 0, "Simulator stop after x number of instructions")
1026 #if defined(V8_TARGET_ARCH_ARM64) || defined(V8_TARGET_ARCH_MIPS64) || \
1027     defined(V8_TARGET_ARCH_PPC64)
1028 DEFINE_INT(sim_stack_alignment, 16,
1029            "Stack alignment in bytes in simulator. This must be a power of two "
1030            "and it must be at least 16. 16 is default.")
1031 #else
1032 DEFINE_INT(sim_stack_alignment, 8,
1033            "Stack alingment in bytes in simulator (4 or 8, 8 is default)")
1034 #endif
1035 DEFINE_INT(sim_stack_size, 2 * MB / KB,
1036            "Stack size of the ARM64, MIPS64 and PPC64 simulator "
1037            "in kBytes (default is 2 MB)")
1038 DEFINE_BOOL(log_colour, ENABLE_LOG_COLOUR,
1039             "When logging, try to use coloured output.")
1040 DEFINE_BOOL(ignore_asm_unimplemented_break, false,
1041             "Don't break for ASM_UNIMPLEMENTED_BREAK macros.")
1042 DEFINE_BOOL(trace_sim_messages, false,
1043             "Trace simulator debug messages. Implied by --trace-sim.")
1044 
1045 // isolate.cc
1046 DEFINE_BOOL(stack_trace_on_illegal, false,
1047             "print stack trace when an illegal exception is thrown")
1048 DEFINE_BOOL(abort_on_uncaught_exception, false,
1049             "abort program (dump core) when an uncaught exception is thrown")
1050 DEFINE_BOOL(abort_on_stack_or_string_length_overflow, false,
1051             "Abort program when the stack overflows or a string exceeds "
1052             "maximum length (as opposed to throwing RangeError). This is "
1053             "useful for fuzzing where the spec behaviour would introduce "
1054             "nondeterminism.")
1055 DEFINE_BOOL(randomize_hashes, true,
1056             "randomize hashes to avoid predictable hash collisions "
1057             "(with snapshots this option cannot override the baked-in seed)")
1058 DEFINE_BOOL(rehash_snapshot, true,
1059             "rehash strings from the snapshot to override the baked-in seed")
1060 DEFINE_UINT64(hash_seed, 0,
1061               "Fixed seed to use to hash property keys (0 means random)"
1062               "(with snapshots this option cannot override the baked-in seed)")
1063 DEFINE_INT(random_seed, 0,
1064            "Default seed for initializing random generator "
1065            "(0, the default, means to use system random).")
1066 DEFINE_INT(fuzzer_random_seed, 0,
1067            "Default seed for initializing fuzzer random generator "
1068            "(0, the default, means to use v8's random number generator seed).")
1069 DEFINE_BOOL(trace_rail, false, "trace RAIL mode")
1070 DEFINE_BOOL(print_all_exceptions, false,
1071             "print exception object and stack trace on each thrown exception")
1072 
1073 // runtime.cc
1074 DEFINE_BOOL(runtime_call_stats, false, "report runtime call counts and times")
1075 DEFINE_INT(runtime_stats, 0,
1076            "internal usage only for controlling runtime statistics")
1077 DEFINE_VALUE_IMPLICATION(runtime_call_stats, runtime_stats, 1)
1078 
1079 // snapshot-common.cc
1080 #ifdef V8_EMBEDDED_BUILTINS
1081 #define V8_EMBEDDED_BUILTINS_BOOL true
1082 #else
1083 #define V8_EMBEDDED_BUILTINS_BOOL false
1084 #endif
1085 DEFINE_BOOL_READONLY(embedded_builtins, V8_EMBEDDED_BUILTINS_BOOL,
1086                      "Embed builtin code into the binary.")
1087 // TODO(jgruber,v8:6666): Remove once ia32 has full embedded builtin support.
1088 DEFINE_BOOL_READONLY(
1089     ia32_verify_root_register, false,
1090     "Check that the value of the root register was not clobbered.")
1091 // TODO(jgruber,v8:6666): Remove once ia32 has full embedded builtin support.
1092 DEFINE_BOOL(print_embedded_builtin_candidates, false,
1093             "Prints builtins that are not yet embedded but could be.")
1094 DEFINE_BOOL(lazy_deserialization, true,
1095             "Deserialize code lazily from the snapshot.")
1096 DEFINE_BOOL(lazy_handler_deserialization, true,
1097             "Deserialize bytecode handlers lazily from the snapshot.")
1098 DEFINE_IMPLICATION(lazy_handler_deserialization, lazy_deserialization)
1099 DEFINE_IMPLICATION(future, lazy_handler_deserialization)
1100 DEFINE_BOOL(trace_lazy_deserialization, false, "Trace lazy deserialization.")
1101 DEFINE_BOOL(profile_deserialization, false,
1102             "Print the time it takes to deserialize the snapshot.")
1103 DEFINE_BOOL(serialization_statistics, false,
1104             "Collect statistics on serialized objects.")
1105 DEFINE_UINT(serialization_chunk_size, 4096,
1106             "Custom size for serialization chunks")
1107 
1108 // Regexp
1109 DEFINE_BOOL(regexp_optimization, true, "generate optimized regexp code")
1110 DEFINE_BOOL(regexp_mode_modifiers, false, "enable inline flags in regexp.")
1111 
1112 // Testing flags test/cctest/test-{flags,api,serialization}.cc
1113 DEFINE_BOOL(testing_bool_flag, true, "testing_bool_flag")
1114 DEFINE_MAYBE_BOOL(testing_maybe_bool_flag, "testing_maybe_bool_flag")
1115 DEFINE_INT(testing_int_flag, 13, "testing_int_flag")
1116 DEFINE_FLOAT(testing_float_flag, 2.5, "float-flag")
1117 DEFINE_STRING(testing_string_flag, "Hello, world!", "string-flag")
1118 DEFINE_INT(testing_prng_seed, 42, "Seed used for threading test randomness")
1119 
1120 // mksnapshot.cc
1121 DEFINE_STRING(embedded_src, nullptr,
1122               "Path for the generated embedded data file. (mksnapshot only)")
1123 DEFINE_STRING(
1124     embedded_variant, nullptr,
1125     "Label to disambiguate symbols in embedded data file. (mksnapshot only)")
1126 DEFINE_STRING(startup_src, nullptr,
1127               "Write V8 startup as C++ src. (mksnapshot only)")
1128 DEFINE_STRING(startup_blob, nullptr,
1129               "Write V8 startup blob file. (mksnapshot only)")
1130 
1131 //
1132 // Minor mark compact collector flags.
1133 //
1134 #ifdef ENABLE_MINOR_MC
1135 DEFINE_BOOL(minor_mc_parallel_marking, true,
1136             "use parallel marking for the young generation")
1137 DEFINE_BOOL(trace_minor_mc_parallel_marking, false,
1138             "trace parallel marking for the young generation")
1139 DEFINE_BOOL(minor_mc, false, "perform young generation mark compact GCs")
1140 #endif  // ENABLE_MINOR_MC
1141 
1142 //
1143 // Dev shell flags
1144 //
1145 
1146 DEFINE_BOOL(help, false, "Print usage message, including flags, on console")
1147 DEFINE_BOOL(dump_counters, false, "Dump counters on exit")
1148 DEFINE_BOOL(dump_counters_nvp, false,
1149             "Dump counters as name-value pairs on exit")
1150 DEFINE_BOOL(use_external_strings, false, "Use external strings for source code")
1151 
1152 DEFINE_STRING(map_counters, "", "Map counters to a file")
1153 DEFINE_ARGS(js_arguments,
1154             "Pass all remaining arguments to the script. Alias for \"--\".")
1155 DEFINE_BOOL(mock_arraybuffer_allocator, false,
1156             "Use a mock ArrayBuffer allocator for testing.")
1157 
1158 //
1159 // GDB JIT integration flags.
1160 //
1161 #undef FLAG
1162 #ifdef ENABLE_GDB_JIT_INTERFACE
1163 #define FLAG FLAG_FULL
1164 #else
1165 #define FLAG FLAG_READONLY
1166 #endif
1167 
1168 DEFINE_BOOL(gdbjit, false, "enable GDBJIT interface")
1169 DEFINE_BOOL(gdbjit_full, false, "enable GDBJIT interface for all code objects")
1170 DEFINE_BOOL(gdbjit_dump, false, "dump elf objects with debug info to disk")
1171 DEFINE_STRING(gdbjit_dump_filter, "",
1172               "dump only objects containing this substring")
1173 
1174 #ifdef ENABLE_GDB_JIT_INTERFACE
1175 DEFINE_IMPLICATION(gdbjit_full, gdbjit)
1176 DEFINE_IMPLICATION(gdbjit_dump, gdbjit)
1177 #endif
1178 DEFINE_NEG_IMPLICATION(gdbjit, compact_code_space)
1179 
1180 //
1181 // Debug only flags
1182 //
1183 #undef FLAG
1184 #ifdef DEBUG
1185 #define FLAG FLAG_FULL
1186 #else
1187 #define FLAG FLAG_READONLY
1188 #endif
1189 
1190 // checks.cc
1191 #ifdef ENABLE_SLOW_DCHECKS
1192 DEFINE_BOOL(enable_slow_asserts, true,
1193             "enable asserts that are slow to execute")
1194 #endif
1195 
1196 // codegen-ia32.cc / codegen-arm.cc / macro-assembler-*.cc
1197 DEFINE_BOOL(print_ast, false, "print source AST")
1198 DEFINE_BOOL(trap_on_abort, false, "replace aborts by breakpoints")
1199 
1200 // compiler.cc
1201 DEFINE_BOOL(print_builtin_scopes, false, "print scopes for builtins")
1202 DEFINE_BOOL(print_scopes, false, "print scopes")
1203 
1204 // contexts.cc
1205 DEFINE_BOOL(trace_contexts, false, "trace contexts operations")
1206 
1207 // heap.cc
1208 DEFINE_BOOL(gc_verbose, false, "print stuff during garbage collection")
1209 DEFINE_BOOL(code_stats, false, "report code statistics after GC")
1210 DEFINE_BOOL(print_handles, false, "report handles after GC")
1211 DEFINE_BOOL(check_handle_count, false,
1212             "Check that there are not too many handles at GC")
1213 DEFINE_BOOL(print_global_handles, false, "report global handles after GC")
1214 
1215 // TurboFan debug-only flags.
1216 DEFINE_BOOL(trace_turbo_escape, false, "enable tracing in escape analysis")
1217 
1218 // objects.cc
1219 DEFINE_BOOL(trace_module_status, false,
1220             "Trace status transitions of ECMAScript modules")
1221 DEFINE_BOOL(trace_normalization, false,
1222             "prints when objects are turned into dictionaries.")
1223 
1224 // runtime.cc
1225 DEFINE_BOOL(trace_lazy, false, "trace lazy compilation")
1226 
1227 // spaces.cc
1228 DEFINE_BOOL(collect_heap_spill_statistics, false,
1229             "report heap spill statistics along with heap_stats "
1230             "(requires heap_stats)")
1231 DEFINE_BOOL(trace_isolates, false, "trace isolate state changes")
1232 
1233 // Regexp
1234 DEFINE_BOOL(regexp_possessive_quantifier, false,
1235             "enable possessive quantifier syntax for testing")
1236 DEFINE_BOOL(trace_regexp_bytecodes, false, "trace regexp bytecode execution")
1237 DEFINE_BOOL(trace_regexp_assembler, false,
1238             "trace regexp macro assembler calls.")
1239 DEFINE_BOOL(trace_regexp_parser, false, "trace regexp parsing")
1240 
1241 // Debugger
1242 DEFINE_BOOL(print_break_location, false, "print source location on debug break")
1243 
1244 // wasm instance management
1245 DEFINE_DEBUG_BOOL(trace_wasm_instances, false,
1246                   "trace creation and collection of wasm instances")
1247 
1248 //
1249 // Logging and profiling flags
1250 //
1251 #undef FLAG
1252 #define FLAG FLAG_FULL
1253 
1254 // log.cc
1255 DEFINE_BOOL(log, false,
1256             "Minimal logging (no API, code, GC, suspect, or handles samples).")
1257 DEFINE_BOOL(log_all, false, "Log all events to the log file.")
1258 DEFINE_BOOL(log_api, false, "Log API events to the log file.")
1259 DEFINE_BOOL(log_code, false,
1260             "Log code events to the log file without profiling.")
1261 DEFINE_BOOL(log_handles, false, "Log global handle events.")
1262 DEFINE_BOOL(log_suspect, false, "Log suspect operations.")
1263 DEFINE_BOOL(log_source_code, false, "Log source code.")
1264 DEFINE_BOOL(log_function_events, false,
1265             "Log function events "
1266             "(parse, compile, execute) separately.")
1267 DEFINE_BOOL(prof, false,
1268             "Log statistical profiling information (implies --log-code).")
1269 
1270 DEFINE_BOOL(detailed_line_info, false,
1271             "Always generate detailed line information for CPU profiling.")
1272 
1273 #if defined(ANDROID)
1274 // Phones and tablets have processors that are much slower than desktop
1275 // and laptop computers for which current heuristics are tuned.
1276 #define DEFAULT_PROF_SAMPLING_INTERVAL 5000
1277 #else
1278 #define DEFAULT_PROF_SAMPLING_INTERVAL 1000
1279 #endif
1280 DEFINE_INT(prof_sampling_interval, DEFAULT_PROF_SAMPLING_INTERVAL,
1281            "Interval for --prof samples (in microseconds).")
1282 #undef DEFAULT_PROF_SAMPLING_INTERVAL
1283 
1284 DEFINE_BOOL(prof_cpp, false, "Like --prof, but ignore generated code.")
1285 DEFINE_IMPLICATION(prof, prof_cpp)
1286 DEFINE_BOOL(prof_browser_mode, true,
1287             "Used with --prof, turns on browser-compatible mode for profiling.")
1288 DEFINE_STRING(logfile, "v8.log", "Specify the name of the log file.")
1289 DEFINE_BOOL(logfile_per_isolate, true, "Separate log files for each isolate.")
1290 DEFINE_BOOL(ll_prof, false, "Enable low-level linux profiler.")
1291 DEFINE_BOOL(interpreted_frames_native_stack, false,
1292             "Show interpreted frames on the native stack (useful for external "
1293             "profilers).")
1294 DEFINE_BOOL(perf_basic_prof, false,
1295             "Enable perf linux profiler (basic support).")
1296 DEFINE_NEG_IMPLICATION(perf_basic_prof, compact_code_space)
1297 DEFINE_BOOL(perf_basic_prof_only_functions, false,
1298             "Only report function code ranges to perf (i.e. no stubs).")
1299 DEFINE_IMPLICATION(perf_basic_prof_only_functions, perf_basic_prof)
1300 DEFINE_BOOL(perf_prof, false,
1301             "Enable perf linux profiler (experimental annotate support).")
1302 DEFINE_NEG_IMPLICATION(perf_prof, compact_code_space)
1303 DEFINE_BOOL(perf_prof_unwinding_info, false,
1304             "Enable unwinding info for perf linux profiler (experimental).")
1305 DEFINE_IMPLICATION(perf_prof, perf_prof_unwinding_info)
1306 DEFINE_STRING(gc_fake_mmap, "/tmp/__v8_gc__",
1307               "Specify the name of the file for fake gc mmap used in ll_prof")
1308 DEFINE_BOOL(log_internal_timer_events, false, "Time internal events.")
1309 DEFINE_BOOL(log_timer_events, false,
1310             "Time events including external callbacks.")
1311 DEFINE_IMPLICATION(log_timer_events, log_internal_timer_events)
1312 DEFINE_IMPLICATION(log_internal_timer_events, prof)
1313 DEFINE_BOOL(log_instruction_stats, false, "Log AArch64 instruction statistics.")
1314 DEFINE_STRING(log_instruction_file, "arm64_inst.csv",
1315               "AArch64 instruction statistics log file.")
1316 DEFINE_INT(log_instruction_period, 1 << 22,
1317            "AArch64 instruction statistics logging period.")
1318 
1319 DEFINE_BOOL(redirect_code_traces, false,
1320             "output deopt information and disassembly into file "
1321             "code-<pid>-<isolate id>.asm")
1322 DEFINE_STRING(redirect_code_traces_to, nullptr,
1323               "output deopt information and disassembly into the given file")
1324 
1325 DEFINE_BOOL(print_opt_source, false,
1326             "print source code of optimized and inlined functions")
1327 
1328 //
1329 // Disassembler only flags
1330 //
1331 #undef FLAG
1332 #ifdef ENABLE_DISASSEMBLER
1333 #define FLAG FLAG_FULL
1334 #else
1335 #define FLAG FLAG_READONLY
1336 #endif
1337 
1338 // elements.cc
1339 DEFINE_BOOL(trace_elements_transitions, false, "trace elements transitions")
1340 
1341 DEFINE_BOOL(trace_creation_allocation_sites, false,
1342             "trace the creation of allocation sites")
1343 
1344 // code-stubs.cc
1345 DEFINE_BOOL(print_code_stubs, false, "print code stubs")
1346 DEFINE_BOOL(test_secondary_stub_cache, false,
1347             "test secondary stub cache by disabling the primary one")
1348 
1349 DEFINE_BOOL(test_primary_stub_cache, false,
1350             "test primary stub cache by disabling the secondary one")
1351 
1352 DEFINE_BOOL(test_small_max_function_context_stub_size, false,
1353             "enable testing the function context size overflow path "
1354             "by making the maximum size smaller")
1355 
1356 // codegen-ia32.cc / codegen-arm.cc
1357 DEFINE_BOOL(print_code, false, "print generated code")
1358 DEFINE_BOOL(print_opt_code, false, "print optimized code")
1359 DEFINE_STRING(print_opt_code_filter, "*", "filter for printing optimized code")
1360 DEFINE_BOOL(print_code_verbose, false, "print more information for code")
1361 DEFINE_BOOL(print_builtin_code, false, "print generated code for builtins")
1362 DEFINE_STRING(print_builtin_code_filter, "*",
1363               "filter for printing builtin code")
1364 DEFINE_BOOL(print_builtin_size, false, "print code size for builtins")
1365 
1366 #ifdef ENABLE_DISASSEMBLER
1367 DEFINE_BOOL(sodium, false,
1368             "print generated code output suitable for use with "
1369             "the Sodium code viewer")
1370 
1371 DEFINE_IMPLICATION(sodium, print_code_stubs)
1372 DEFINE_IMPLICATION(sodium, print_code)
1373 DEFINE_IMPLICATION(sodium, print_opt_code)
1374 DEFINE_IMPLICATION(sodium, code_comments)
1375 
1376 DEFINE_BOOL(print_all_code, false, "enable all flags related to printing code")
1377 DEFINE_IMPLICATION(print_all_code, print_code)
1378 DEFINE_IMPLICATION(print_all_code, print_opt_code)
1379 DEFINE_IMPLICATION(print_all_code, print_code_verbose)
1380 DEFINE_IMPLICATION(print_all_code, print_builtin_code)
1381 DEFINE_IMPLICATION(print_all_code, print_code_stubs)
1382 DEFINE_IMPLICATION(print_all_code, code_comments)
1383 #endif
1384 
1385 #undef FLAG
1386 #define FLAG FLAG_FULL
1387 
1388 //
1389 // Predictable mode related flags.
1390 //
1391 
1392 DEFINE_BOOL(predictable, false, "enable predictable mode")
1393 DEFINE_IMPLICATION(predictable, single_threaded)
1394 DEFINE_NEG_IMPLICATION(predictable, memory_reducer)
1395 DEFINE_VALUE_IMPLICATION(single_threaded, wasm_num_compilation_tasks, 0)
1396 DEFINE_NEG_IMPLICATION(single_threaded, wasm_async_compilation)
1397 
1398 //
1399 // Threading related flags.
1400 //
1401 
1402 DEFINE_BOOL(single_threaded, false, "disable the use of background tasks")
1403 DEFINE_IMPLICATION(single_threaded, single_threaded_gc)
1404 DEFINE_NEG_IMPLICATION(single_threaded, concurrent_recompilation)
1405 DEFINE_NEG_IMPLICATION(single_threaded, compiler_dispatcher)
1406 
1407 //
1408 // Parallel and concurrent GC (Orinoco) related flags.
1409 //
1410 DEFINE_BOOL(single_threaded_gc, false, "disable the use of background gc tasks")
1411 DEFINE_NEG_IMPLICATION(single_threaded_gc, concurrent_marking)
1412 DEFINE_NEG_IMPLICATION(single_threaded_gc, concurrent_sweeping)
1413 DEFINE_NEG_IMPLICATION(single_threaded_gc, parallel_compaction)
1414 DEFINE_NEG_IMPLICATION(single_threaded_gc, parallel_marking)
1415 DEFINE_NEG_IMPLICATION(single_threaded_gc, parallel_pointer_update)
1416 DEFINE_NEG_IMPLICATION(single_threaded_gc, parallel_scavenge)
1417 DEFINE_NEG_IMPLICATION(single_threaded_gc, concurrent_store_buffer)
1418 #ifdef ENABLE_MINOR_MC
1419 DEFINE_NEG_IMPLICATION(single_threaded_gc, minor_mc_parallel_marking)
1420 #endif  // ENABLE_MINOR_MC
1421 DEFINE_NEG_IMPLICATION(single_threaded_gc, concurrent_array_buffer_freeing)
1422 
1423 #undef FLAG
1424 
1425 #ifdef VERIFY_PREDICTABLE
1426 #define FLAG FLAG_FULL
1427 #else
1428 #define FLAG FLAG_READONLY
1429 #endif
1430 
1431 DEFINE_BOOL(verify_predictable, false,
1432             "this mode is used for checking that V8 behaves predictably")
1433 DEFINE_INT(dump_allocations_digest_at_alloc, -1,
1434            "dump allocations digest each n-th allocation")
1435 
1436 //
1437 // Read-only flags
1438 //
1439 #undef FLAG
1440 #define FLAG FLAG_READONLY
1441 
1442 // assembler.h
1443 DEFINE_BOOL(enable_embedded_constant_pool, V8_EMBEDDED_CONSTANT_POOL,
1444             "enable use of embedded constant pools (PPC only)")
1445 
1446 DEFINE_BOOL(unbox_double_fields, V8_DOUBLE_FIELDS_UNBOXING,
1447             "enable in-object double fields unboxing (64-bit only)")
1448 DEFINE_IMPLICATION(unbox_double_fields, track_double_fields)
1449 
1450 // Cleanup...
1451 #undef FLAG_FULL
1452 #undef FLAG_READONLY
1453 #undef FLAG
1454 #undef FLAG_ALIAS
1455 
1456 #undef DEFINE_BOOL
1457 #undef DEFINE_MAYBE_BOOL
1458 #undef DEFINE_DEBUG_BOOL
1459 #undef DEFINE_INT
1460 #undef DEFINE_STRING
1461 #undef DEFINE_FLOAT
1462 #undef DEFINE_ARGS
1463 #undef DEFINE_IMPLICATION
1464 #undef DEFINE_NEG_IMPLICATION
1465 #undef DEFINE_NEG_VALUE_IMPLICATION
1466 #undef DEFINE_VALUE_IMPLICATION
1467 #undef DEFINE_ALIAS_BOOL
1468 #undef DEFINE_ALIAS_INT
1469 #undef DEFINE_ALIAS_STRING
1470 #undef DEFINE_ALIAS_FLOAT
1471 #undef DEFINE_ALIAS_ARGS
1472 
1473 #undef FLAG_MODE_DECLARE
1474 #undef FLAG_MODE_DEFINE
1475 #undef FLAG_MODE_DEFINE_DEFAULTS
1476 #undef FLAG_MODE_META
1477 #undef FLAG_MODE_DEFINE_IMPLICATIONS
1478 
1479 #undef COMMA
1480