V8 API Reference, 7.2.502.16 (for Deno 0.2.4)
flag-definitions.h
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 
101 struct MaybeBoolFlag {
102  static MaybeBoolFlag Create(bool has_value, bool value) {
103  MaybeBoolFlag flag;
104  flag.has_value = has_value;
105  flag.value = value;
106  return flag;
107  }
108  bool has_value;
109  bool value;
110 };
111 #endif
112 
113 #ifdef DEBUG
114 #define DEBUG_BOOL true
115 #else
116 #define DEBUG_BOOL false
117 #endif
118 
119 // Supported ARM configurations are:
120 // "armv6": ARMv6 + VFPv2
121 // "armv7": ARMv7 + VFPv3-D32 + NEON
122 // "armv7+sudiv": ARMv7 + VFPv4-D32 + NEON + SUDIV
123 // "armv8": ARMv8 (including all of the above)
124 #if !defined(ARM_TEST_NO_FEATURE_PROBE) || \
125  (defined(CAN_USE_ARMV8_INSTRUCTIONS) && \
126  defined(CAN_USE_ARMV7_INSTRUCTIONS) && defined(CAN_USE_SUDIV) && \
127  defined(CAN_USE_NEON) && defined(CAN_USE_VFP3_INSTRUCTIONS))
128 #define ARM_ARCH_DEFAULT "armv8"
129 #elif defined(CAN_USE_ARMV7_INSTRUCTIONS) && defined(CAN_USE_SUDIV) && \
130  defined(CAN_USE_NEON) && defined(CAN_USE_VFP3_INSTRUCTIONS)
131 #define ARM_ARCH_DEFAULT "armv7+sudiv"
132 #elif defined(CAN_USE_ARMV7_INSTRUCTIONS) && defined(CAN_USE_NEON) && \
133  defined(CAN_USE_VFP3_INSTRUCTIONS)
134 #define ARM_ARCH_DEFAULT "armv7"
135 #else
136 #define ARM_ARCH_DEFAULT "armv6"
137 #endif
138 
139 #ifdef V8_OS_WIN
140 # define ENABLE_LOG_COLOUR false
141 #else
142 # define ENABLE_LOG_COLOUR true
143 #endif
144 
145 #define DEFINE_BOOL(nam, def, cmt) FLAG(BOOL, bool, nam, def, cmt)
146 #define DEFINE_BOOL_READONLY(nam, def, cmt) \
147  FLAG_READONLY(BOOL, bool, nam, def, cmt)
148 #define DEFINE_MAYBE_BOOL(nam, cmt) \
149  FLAG(MAYBE_BOOL, MaybeBoolFlag, nam, {false COMMA false}, cmt)
150 #define DEFINE_INT(nam, def, cmt) FLAG(INT, int, nam, def, cmt)
151 #define DEFINE_UINT(nam, def, cmt) FLAG(UINT, unsigned int, nam, def, cmt)
152 #define DEFINE_UINT64(nam, def, cmt) FLAG(UINT64, uint64_t, nam, def, cmt)
153 #define DEFINE_FLOAT(nam, def, cmt) FLAG(FLOAT, double, nam, def, cmt)
154 #define DEFINE_SIZE_T(nam, def, cmt) FLAG(SIZE_T, size_t, nam, def, cmt)
155 #define DEFINE_STRING(nam, def, cmt) FLAG(STRING, const char*, nam, def, cmt)
156 #define DEFINE_ALIAS_BOOL(alias, nam) FLAG_ALIAS(BOOL, bool, alias, nam)
157 #define DEFINE_ALIAS_INT(alias, nam) FLAG_ALIAS(INT, int, alias, nam)
158 #define DEFINE_ALIAS_FLOAT(alias, nam) FLAG_ALIAS(FLOAT, double, alias, nam)
159 #define DEFINE_ALIAS_SIZE_T(alias, nam) FLAG_ALIAS(SIZE_T, size_t, alias, nam)
160 #define DEFINE_ALIAS_STRING(alias, nam) \
161  FLAG_ALIAS(STRING, const char*, alias, nam)
162 
163 #ifdef DEBUG
164 #define DEFINE_DEBUG_BOOL DEFINE_BOOL
165 #else
166 #define DEFINE_DEBUG_BOOL DEFINE_BOOL_READONLY
167 #endif
168 
169 //
170 // Flags in all modes.
171 //
172 #define FLAG FLAG_FULL
173 
174 DEFINE_BOOL(experimental_extras, false,
175  "enable code compiled in via v8_experimental_extra_library_files")
176 
177 // Flags for language modes and experimental language features.
178 DEFINE_BOOL(use_strict, false, "enforce strict mode")
179 
180 DEFINE_BOOL(es_staging, false,
181  "enable test-worthy harmony features (for internal use only)")
182 DEFINE_BOOL(harmony, false, "enable all completed harmony features")
183 DEFINE_BOOL(harmony_shipping, true, "enable all shipped harmony features")
184 DEFINE_IMPLICATION(es_staging, harmony)
185 // Enabling import.meta requires to also enable import()
186 DEFINE_IMPLICATION(harmony_import_meta, harmony_dynamic_import)
187 
188 DEFINE_IMPLICATION(harmony_class_fields, harmony_public_fields)
189 DEFINE_IMPLICATION(harmony_class_fields, harmony_static_fields)
190 DEFINE_IMPLICATION(harmony_class_fields, harmony_private_fields)
191 
192 DEFINE_IMPLICATION(harmony_private_methods, harmony_private_fields)
193 
194 // Update bootstrapper.cc whenever adding a new feature flag.
195 
196 // Features that are still work in progress (behind individual flags).
197 #define HARMONY_INPROGRESS_BASE(V) \
198  V(harmony_class_fields, "harmony fields in class literals") \
199  V(harmony_await_optimization, "harmony await taking 1 tick") \
200  V(harmony_private_methods, "harmony private methods in class literals") \
201  V(harmony_regexp_sequence, "RegExp Unicode sequence properties") \
202  V(harmony_weak_refs, "harmony weak references") \
203  V(harmony_object_from_entries, "harmony Object.fromEntries()")
204 
205 #ifdef V8_INTL_SUPPORT
206 #define HARMONY_INPROGRESS(V) \
207  HARMONY_INPROGRESS_BASE(V) \
208  V(harmony_locale, "Intl.Locale")
209 #else
210 #define HARMONY_INPROGRESS(V) HARMONY_INPROGRESS_BASE(V)
211 #endif
212 
213 // Features that are complete (but still behind --harmony/es-staging flag).
214 #define HARMONY_STAGED_BASE(V) \
215  V(harmony_private_fields, "harmony private fields in class literals") \
216  V(harmony_numeric_separator, "harmony numeric separator between digits") \
217  V(harmony_string_matchall, "harmony String.prototype.matchAll")
218 
219 #ifdef V8_INTL_SUPPORT
220 #define HARMONY_STAGED(V) \
221  HARMONY_STAGED_BASE(V) \
222  V(harmony_intl_segmenter, "Intl.Segmenter")
223 #else
224 #define HARMONY_STAGED(V) HARMONY_STAGED_BASE(V)
225 #endif
226 
227 // Features that are shipping (turned on by default, but internal flag remains).
228 #define HARMONY_SHIPPING_BASE(V) \
229  V(harmony_namespace_exports, \
230  "harmony namespace exports (export * as foo from 'bar')") \
231  V(harmony_sharedarraybuffer, "harmony sharedarraybuffer") \
232  V(harmony_import_meta, "harmony import.meta property") \
233  V(harmony_dynamic_import, "harmony dynamic import") \
234  V(harmony_array_prototype_values, "harmony Array.prototype.values") \
235  V(harmony_array_flat, "harmony Array.prototype.{flat,flatMap}") \
236  V(harmony_symbol_description, "harmony Symbol.prototype.description") \
237  V(harmony_global, "harmony global") \
238  V(harmony_json_stringify, "well-formed JSON.stringify") \
239  V(harmony_public_fields, "harmony public instance fields in class literals") \
240  V(harmony_static_fields, "harmony static fields in class literals")
241 
242 #ifdef V8_INTL_SUPPORT
243 #define HARMONY_SHIPPING(V) \
244  HARMONY_SHIPPING_BASE(V) \
245  V(harmony_intl_list_format, "Intl.ListFormat") \
246  V(harmony_intl_relative_time_format, "Intl.RelativeTimeFormat")
247 #else
248 #define HARMONY_SHIPPING(V) HARMONY_SHIPPING_BASE(V)
249 #endif
250 
251 // Once a shipping feature has proved stable in the wild, it will be dropped
252 // from HARMONY_SHIPPING, all occurrences of the FLAG_ variable are removed,
253 // and associated tests are moved from the harmony directory to the appropriate
254 // esN directory.
255 
256 
257 #define FLAG_INPROGRESS_FEATURES(id, description) \
258  DEFINE_BOOL(id, false, "enable " #description " (in progress)")
259 HARMONY_INPROGRESS(FLAG_INPROGRESS_FEATURES)
260 #undef FLAG_INPROGRESS_FEATURES
261 
262 #define FLAG_STAGED_FEATURES(id, description) \
263  DEFINE_BOOL(id, false, "enable " #description) \
264  DEFINE_IMPLICATION(harmony, id)
265 HARMONY_STAGED(FLAG_STAGED_FEATURES)
266 #undef FLAG_STAGED_FEATURES
267 
268 #define FLAG_SHIPPING_FEATURES(id, description) \
269  DEFINE_BOOL(id, true, "enable " #description) \
270  DEFINE_NEG_NEG_IMPLICATION(harmony_shipping, id)
271 HARMONY_SHIPPING(FLAG_SHIPPING_FEATURES)
272 #undef FLAG_SHIPPING_FEATURES
273 
274 #ifdef V8_INTL_SUPPORT
275 DEFINE_BOOL(icu_timezone_data, true, "get information about timezones from ICU")
276 #endif
277 
278 #ifdef V8_ENABLE_FUTURE
279 #define FUTURE_BOOL true
280 #else
281 #define FUTURE_BOOL false
282 #endif
283 DEFINE_BOOL(future, FUTURE_BOOL,
284  "Implies all staged features that we want to ship in the "
285  "not-too-far future")
286 
287 DEFINE_IMPLICATION(future, write_protect_code_memory)
288 
289 // Flags for experimental implementation features.
290 DEFINE_BOOL(allocation_site_pretenuring, true,
291  "pretenure with allocation sites")
292 DEFINE_BOOL(page_promotion, true, "promote pages based on utilization")
293 DEFINE_INT(page_promotion_threshold, 70,
294  "min percentage of live bytes on a page to enable fast evacuation")
295 DEFINE_BOOL(trace_pretenuring, false,
296  "trace pretenuring decisions of HAllocate instructions")
297 DEFINE_BOOL(trace_pretenuring_statistics, false,
298  "trace allocation site pretenuring statistics")
299 DEFINE_BOOL(track_fields, true, "track fields with only smi values")
300 DEFINE_BOOL(track_double_fields, true, "track fields with double values")
301 DEFINE_BOOL(track_heap_object_fields, true, "track fields with heap values")
302 DEFINE_BOOL(track_computed_fields, true, "track computed boilerplate fields")
303 DEFINE_IMPLICATION(track_double_fields, track_fields)
304 DEFINE_IMPLICATION(track_heap_object_fields, track_fields)
305 DEFINE_IMPLICATION(track_computed_fields, track_fields)
306 DEFINE_BOOL(track_field_types, true, "track field types")
307 DEFINE_IMPLICATION(track_field_types, track_fields)
308 DEFINE_IMPLICATION(track_field_types, track_heap_object_fields)
309 DEFINE_BOOL(trace_block_coverage, false,
310  "trace collected block coverage information")
311 DEFINE_BOOL(feedback_normalization, false,
312  "feed back normalization to constructors")
313 // TODO(jkummerow): This currently adds too much load on the stub cache.
314 DEFINE_BOOL_READONLY(internalize_on_the_fly, true,
315  "internalize string keys for generic keyed ICs on the fly")
316 
317 // Flag for one shot optimiztions.
318 DEFINE_BOOL(enable_one_shot_optimization, true,
319  "Enable size optimizations for the code that will "
320  "only be executed once")
321 
322 
323 // Flags for data representation optimizations
324 DEFINE_BOOL(unbox_double_arrays, true, "automatically unbox arrays of doubles")
325 DEFINE_BOOL_READONLY(string_slices, true, "use string slices")
326 
327 // Flags for Ignition for no-snapshot builds.
328 #undef FLAG
329 #ifndef V8_USE_SNAPSHOT
330 #define FLAG FLAG_FULL
331 #else
332 #define FLAG FLAG_READONLY
333 #endif
334 DEFINE_INT(interrupt_budget, 144 * KB,
335  "interrupt budget which should be used for the profiler counter")
336 #undef FLAG
337 #define FLAG FLAG_FULL
338 
339 // Flags for Ignition.
340 DEFINE_BOOL(ignition_elide_noneffectful_bytecodes, true,
341  "elide bytecodes which won't have any external effect")
342 DEFINE_BOOL(ignition_reo, true, "use ignition register equivalence optimizer")
343 DEFINE_BOOL(ignition_filter_expression_positions, true,
344  "filter expression positions before the bytecode pipeline")
345 DEFINE_BOOL(ignition_share_named_property_feedback, true,
346  "share feedback slots when loading the same named property from "
347  "the same object")
348 DEFINE_BOOL(print_bytecode, false,
349  "print bytecode generated by ignition interpreter")
350 DEFINE_STRING(print_bytecode_filter, "*",
351  "filter for selecting which functions to print bytecode")
352 #ifdef V8_TRACE_IGNITION
353 DEFINE_BOOL(trace_ignition, false,
354  "trace the bytecodes executed by the ignition interpreter")
355 #endif
356 #ifdef V8_TRACE_FEEDBACK_UPDATES
357 DEFINE_BOOL(
358  trace_feedback_updates, false,
359  "trace updates to feedback vectors during ignition interpreter execution.")
360 #endif
361 DEFINE_BOOL(trace_ignition_codegen, false,
362  "trace the codegen of ignition interpreter bytecode handlers")
363 DEFINE_BOOL(trace_ignition_dispatches, false,
364  "traces the dispatches to bytecode handlers by the ignition "
365  "interpreter")
366 DEFINE_STRING(trace_ignition_dispatches_output_file, nullptr,
367  "the file to which the bytecode handler dispatch table is "
368  "written (by default, the table is not written to a file)")
369 
370 DEFINE_BOOL(fast_math, true, "faster (but maybe less accurate) math functions")
371 DEFINE_BOOL(trace_track_allocation_sites, false,
372  "trace the tracking of allocation sites")
373 DEFINE_BOOL(trace_migration, false, "trace object migration")
374 DEFINE_BOOL(trace_generalization, false, "trace map generalization")
375 
376 // Flags for concurrent recompilation.
377 DEFINE_BOOL(concurrent_recompilation, true,
378  "optimizing hot functions asynchronously on a separate thread")
379 DEFINE_BOOL(trace_concurrent_recompilation, false,
380  "track concurrent recompilation")
381 DEFINE_INT(concurrent_recompilation_queue_length, 8,
382  "the length of the concurrent compilation queue")
383 DEFINE_INT(concurrent_recompilation_delay, 0,
384  "artificial compilation delay in ms")
385 DEFINE_BOOL(block_concurrent_recompilation, false,
386  "block queued jobs until released")
387 DEFINE_BOOL(concurrent_inlining, false,
388  "run optimizing compiler's inlining phase on a separate thread")
389 DEFINE_IMPLICATION(future, concurrent_inlining)
390 DEFINE_BOOL(trace_heap_broker, false, "trace the heap broker")
391 
392 // Flags for stress-testing the compiler.
393 DEFINE_INT(stress_runs, 0, "number of stress runs")
394 DEFINE_INT(deopt_every_n_times, 0,
395  "deoptimize every n times a deopt point is passed")
396 DEFINE_BOOL(print_deopt_stress, false, "print number of possible deopt points")
397 
398 // Flags for TurboFan.
399 DEFINE_BOOL(turbo_sp_frame_access, false,
400  "use stack pointer-relative access to frame wherever possible")
401 DEFINE_BOOL(turbo_preprocess_ranges, true,
402  "run pre-register allocation heuristics")
403 DEFINE_STRING(turbo_filter, "*", "optimization filter for TurboFan compiler")
404 DEFINE_BOOL(trace_turbo, false, "trace generated TurboFan IR")
405 DEFINE_STRING(trace_turbo_path, nullptr,
406  "directory to dump generated TurboFan IR to")
407 DEFINE_STRING(trace_turbo_filter, "*",
408  "filter for tracing turbofan compilation")
409 DEFINE_BOOL(trace_turbo_graph, false, "trace generated TurboFan graphs")
410 DEFINE_BOOL(trace_turbo_scheduled, false, "trace TurboFan IR with schedule")
411 DEFINE_IMPLICATION(trace_turbo_scheduled, trace_turbo_graph)
412 DEFINE_STRING(trace_turbo_cfg_file, nullptr,
413  "trace turbo cfg graph (for C1 visualizer) to a given file name")
414 DEFINE_BOOL(trace_turbo_types, true, "trace TurboFan's types")
415 DEFINE_BOOL(trace_turbo_scheduler, false, "trace TurboFan's scheduler")
416 DEFINE_BOOL(trace_turbo_reduction, false, "trace TurboFan's various reducers")
417 DEFINE_BOOL(trace_turbo_trimming, false, "trace TurboFan's graph trimmer")
418 DEFINE_BOOL(trace_turbo_jt, false, "trace TurboFan's jump threading")
419 DEFINE_BOOL(trace_turbo_ceq, false, "trace TurboFan's control equivalence")
420 DEFINE_BOOL(trace_turbo_loop, false, "trace TurboFan's loop optimizations")
421 DEFINE_BOOL(trace_alloc, false, "trace register allocator")
422 DEFINE_BOOL(trace_all_uses, false, "trace all use positions")
423 DEFINE_BOOL(trace_representation, false, "trace representation types")
424 DEFINE_BOOL(turbo_verify, DEBUG_BOOL, "verify TurboFan graphs at each phase")
425 DEFINE_STRING(turbo_verify_machine_graph, nullptr,
426  "verify TurboFan machine graph before instruction selection")
427 #ifdef ENABLE_VERIFY_CSA
428 DEFINE_BOOL(verify_csa, DEBUG_BOOL,
429  "verify TurboFan machine graph of code stubs")
430 #else
431 // Define the flag as read-only-false so that code still compiles even in the
432 // non-ENABLE_VERIFY_CSA configuration.
433 DEFINE_BOOL_READONLY(verify_csa, false,
434  "verify TurboFan machine graph of code stubs")
435 #endif
436 DEFINE_BOOL(trace_verify_csa, false, "trace code stubs verification")
437 DEFINE_STRING(csa_trap_on_node, nullptr,
438  "trigger break point when a node with given id is created in "
439  "given stub. The format is: StubName,NodeId")
440 DEFINE_BOOL_READONLY(optimize_csa, true,
441  "run the optimizing Turbofan backend in the CSA pipeline")
442 DEFINE_NEG_IMPLICATION(optimize_csa, turbo_rewrite_far_jumps)
443 DEFINE_BOOL_READONLY(fixed_array_bounds_checks, DEBUG_BOOL,
444  "enable FixedArray bounds checks")
445 DEFINE_BOOL(turbo_stats, false, "print TurboFan statistics")
446 DEFINE_BOOL(turbo_stats_nvp, false,
447  "print TurboFan statistics in machine-readable format")
448 DEFINE_BOOL(turbo_stats_wasm, false,
449  "print TurboFan statistics of wasm compilations")
450 DEFINE_BOOL(turbo_splitting, true, "split nodes during scheduling in TurboFan")
451 DEFINE_BOOL(function_context_specialization, false,
452  "enable function context specialization in TurboFan")
453 DEFINE_BOOL(turbo_inlining, true, "enable inlining in TurboFan")
454 DEFINE_INT(max_inlined_bytecode_size, 500,
455  "maximum size of bytecode for a single inlining")
456 DEFINE_INT(max_inlined_bytecode_size_cumulative, 1000,
457  "maximum cumulative size of bytecode considered for inlining")
458 DEFINE_INT(max_inlined_bytecode_size_absolute, 5000,
459  "maximum cumulative size of bytecode considered for inlining")
460 DEFINE_FLOAT(reserve_inline_budget_scale_factor, 1.2,
461  "maximum cumulative size of bytecode considered for inlining")
462 DEFINE_INT(max_inlined_bytecode_size_small, 30,
463  "maximum size of bytecode considered for small function inlining")
464 DEFINE_FLOAT(min_inlining_frequency, 0.15, "minimum frequency for inlining")
465 DEFINE_BOOL(polymorphic_inlining, true, "polymorphic inlining")
466 DEFINE_BOOL(stress_inline, false,
467  "set high thresholds for inlining to inline as much as possible")
468 DEFINE_VALUE_IMPLICATION(stress_inline, max_inlined_bytecode_size, 999999)
469 DEFINE_VALUE_IMPLICATION(stress_inline, max_inlined_bytecode_size_cumulative,
470  999999)
471 DEFINE_VALUE_IMPLICATION(stress_inline, max_inlined_bytecode_size_absolute,
472  999999)
473 DEFINE_VALUE_IMPLICATION(stress_inline, min_inlining_frequency, 0)
474 DEFINE_VALUE_IMPLICATION(stress_inline, polymorphic_inlining, true)
475 DEFINE_BOOL(trace_turbo_inlining, false, "trace TurboFan inlining")
476 DEFINE_BOOL(inline_accessors, true, "inline JavaScript accessors")
477 DEFINE_BOOL(inline_into_try, true, "inline into try blocks")
478 DEFINE_BOOL(turbo_inline_array_builtins, true,
479  "inline array builtins in TurboFan code")
480 DEFINE_BOOL(use_osr, true, "use on-stack replacement")
481 DEFINE_BOOL(trace_osr, false, "trace on-stack replacement")
482 DEFINE_BOOL(analyze_environment_liveness, true,
483  "analyze liveness of environment slots and zap dead values")
484 DEFINE_BOOL(trace_environment_liveness, false,
485  "trace liveness of local variable slots")
486 DEFINE_BOOL(turbo_load_elimination, true, "enable load elimination in TurboFan")
487 DEFINE_BOOL(trace_turbo_load_elimination, false,
488  "trace TurboFan load elimination")
489 DEFINE_BOOL(turbo_profiling, false, "enable profiling in TurboFan")
490 DEFINE_BOOL(turbo_verify_allocation, DEBUG_BOOL,
491  "verify register allocation in TurboFan")
492 DEFINE_BOOL(turbo_move_optimization, true, "optimize gap moves in TurboFan")
493 DEFINE_BOOL(turbo_jt, true, "enable jump threading in TurboFan")
494 DEFINE_BOOL(turbo_loop_peeling, true, "Turbofan loop peeling")
495 DEFINE_BOOL(turbo_loop_variable, true, "Turbofan loop variable optimization")
496 DEFINE_BOOL(turbo_loop_rotation, true, "Turbofan loop rotation")
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 // Flags for native WebAssembly.
522 DEFINE_BOOL(expose_wasm, true, "expose wasm interface to JavaScript")
523 DEFINE_BOOL(assume_asmjs_origin, false,
524  "force wasm decoder to assume input is internal asm-wasm format")
525 DEFINE_BOOL(wasm_disable_structured_cloning, false,
526  "disable wasm structured cloning")
527 DEFINE_INT(wasm_num_compilation_tasks, 10,
528  "number of parallel compilation tasks for wasm")
529 DEFINE_DEBUG_BOOL(trace_wasm_native_heap, false,
530  "trace wasm native heap events")
531 DEFINE_BOOL(wasm_write_protect_code_memory, false,
532  "write protect code memory on the wasm native heap")
533 DEFINE_BOOL(trace_wasm_serialization, false,
534  "trace serialization/deserialization")
535 DEFINE_BOOL(wasm_async_compilation, true,
536  "enable actual asynchronous compilation for WebAssembly.compile")
537 DEFINE_BOOL(wasm_test_streaming, false,
538  "use streaming compilation instead of async compilation for tests")
539 DEFINE_UINT(wasm_max_mem_pages, v8::internal::wasm::kV8MaxWasmMemoryPages,
540  "maximum number of 64KiB memory pages of a wasm instance")
541 DEFINE_UINT(wasm_max_table_size, v8::internal::wasm::kV8MaxWasmTableSize,
542  "maximum table size of a wasm instance")
543 // Enable Liftoff by default on ia32 and x64. More architectures will follow
544 // once they are implemented and sufficiently tested.
545 #if V8_TARGET_ARCH_IA32 || V8_TARGET_ARCH_X64
546 DEFINE_BOOL(
547  wasm_tier_up, true,
548  "enable wasm baseline compilation and tier up to the optimizing compiler")
549 #else
550 DEFINE_BOOL(
551  wasm_tier_up, false,
552  "enable wasm baseline compilation and tier up to the optimizing compiler")
553 DEFINE_IMPLICATION(future, wasm_tier_up)
554 #endif
555 DEFINE_IMPLICATION(wasm_tier_up, liftoff)
556 DEFINE_DEBUG_BOOL(trace_wasm_decoder, false, "trace decoding of wasm code")
557 DEFINE_DEBUG_BOOL(trace_wasm_decode_time, false,
558  "trace decoding time of wasm code")
559 DEFINE_DEBUG_BOOL(trace_wasm_compiler, false, "trace compiling of wasm code")
560 DEFINE_DEBUG_BOOL(trace_wasm_interpreter, false,
561  "trace interpretation of wasm code")
562 DEFINE_DEBUG_BOOL(trace_wasm_streaming, false,
563  "trace streaming compilation of wasm code")
564 DEFINE_INT(trace_wasm_ast_start, 0,
565  "start function for wasm AST trace (inclusive)")
566 DEFINE_INT(trace_wasm_ast_end, 0, "end function for wasm AST trace (exclusive)")
567 DEFINE_BOOL(liftoff, false,
568  "enable Liftoff, the baseline compiler for WebAssembly")
569 DEFINE_DEBUG_BOOL(trace_liftoff, false,
570  "trace Liftoff, the baseline compiler for WebAssembly")
571 DEFINE_DEBUG_BOOL(wasm_break_on_decoder_error, false,
572  "debug break when wasm decoder encounters an error")
573 DEFINE_BOOL(trace_wasm_memory, false,
574  "print all memory updates performed in wasm code")
575 // Fuzzers use {wasm_tier_mask_for_testing} together with {liftoff} and
576 // {no_wasm_tier_up} to force some functions to be compiled with Turbofan.
577 DEFINE_INT(wasm_tier_mask_for_testing, 0,
578  "bitmask of functions to compile with TurboFan instead of Liftoff")
579 
580 DEFINE_BOOL(validate_asm, true, "validate asm.js modules before compiling")
581 DEFINE_BOOL(suppress_asm_messages, false,
582  "don't emit asm.js related messages (for golden file testing)")
583 DEFINE_BOOL(trace_asm_time, false, "log asm.js timing info to the console")
584 DEFINE_BOOL(trace_asm_scanner, false,
585  "log tokens encountered by asm.js scanner")
586 DEFINE_BOOL(trace_asm_parser, false, "verbose logging of asm.js parse failures")
587 DEFINE_BOOL(stress_validate_asm, false, "try to validate everything as asm.js")
588 
589 DEFINE_DEBUG_BOOL(dump_wasm_module, false, "dump wasm module bytes")
590 DEFINE_STRING(dump_wasm_module_path, nullptr,
591  "directory to dump wasm modules to")
592 
593 // Declare command-line flags for WASM features. Warning: avoid using these
594 // flags directly in the implementation. Instead accept wasm::WasmFeatures
595 // for configurability.
596 #include "src/wasm/wasm-feature-flags.h"
597 
598 #define SPACE
599 #define DECL_WASM_FLAG(feat, desc, val) \
600  DEFINE_BOOL(experimental_wasm_##feat, val, \
601  "enable prototype " desc " for wasm")
602 FOREACH_WASM_FEATURE_FLAG(DECL_WASM_FLAG, SPACE)
603 #undef DECL_WASM_FLAG
604 #undef SPACE
605 
606 DEFINE_BOOL(wasm_opt, false, "enable wasm optimization")
607 DEFINE_BOOL(wasm_no_bounds_checks, false,
608  "disable bounds checks (performance testing only)")
609 DEFINE_BOOL(wasm_no_stack_checks, false,
610  "disable stack checks (performance testing only)")
611 DEFINE_BOOL(wasm_math_intrinsics, true,
612  "intrinsify some Math imports into wasm")
613 
614 DEFINE_BOOL(wasm_shared_engine, true,
615  "shares one wasm engine between all isolates within a process")
616 DEFINE_IMPLICATION(future, wasm_shared_engine)
617 DEFINE_BOOL(wasm_shared_code, true,
618  "shares code underlying a wasm module when it is transferred")
619 DEFINE_IMPLICATION(future, wasm_shared_code)
620 DEFINE_BOOL(wasm_trap_handler, true,
621  "use signal handlers to catch out of bounds memory access in wasm"
622  " (currently Linux x86_64 only)")
623 DEFINE_BOOL(wasm_trap_handler_fallback, false,
624  "Use bounds checks if guarded memory is not available")
625 DEFINE_BOOL(wasm_fuzzer_gen_test, false,
626  "Generate a test case when running a wasm fuzzer")
627 DEFINE_IMPLICATION(wasm_fuzzer_gen_test, single_threaded)
628 DEFINE_BOOL(print_wasm_code, false, "Print WebAssembly code")
629 DEFINE_BOOL(wasm_interpret_all, false,
630  "Execute all wasm code in the wasm interpreter")
631 DEFINE_BOOL(asm_wasm_lazy_compilation, false,
632  "enable lazy compilation for asm-wasm modules")
633 DEFINE_IMPLICATION(validate_asm, asm_wasm_lazy_compilation)
634 DEFINE_BOOL(wasm_lazy_compilation, false,
635  "enable lazy compilation for all wasm modules")
636 DEFINE_DEBUG_BOOL(trace_wasm_lazy_compilation, false,
637  "trace lazy compilation of wasm functions")
638 // wasm-interpret-all resets {asm-,}wasm-lazy-compilation.
639 DEFINE_NEG_IMPLICATION(wasm_interpret_all, asm_wasm_lazy_compilation)
640 DEFINE_NEG_IMPLICATION(wasm_interpret_all, wasm_lazy_compilation)
641 
642 // Profiler flags.
643 DEFINE_INT(frame_count, 1, "number of stack frames inspected by the profiler")
644 DEFINE_INT(type_info_threshold, 25,
645  "percentage of ICs that must have type info to allow optimization")
646 
647 DEFINE_INT(stress_sampling_allocation_profiler, 0,
648  "Enables sampling allocation profiler with X as a sample interval")
649 
650 // Garbage collections flags.
651 DEFINE_SIZE_T(min_semi_space_size, 0,
652  "min size of a semi-space (in MBytes), the new space consists of "
653  "two semi-spaces")
654 DEFINE_SIZE_T(max_semi_space_size, 0,
655  "max size of a semi-space (in MBytes), the new space consists of "
656  "two semi-spaces")
657 DEFINE_INT(semi_space_growth_factor, 2, "factor by which to grow the new space")
658 DEFINE_BOOL(experimental_new_space_growth_heuristic, false,
659  "Grow the new space based on the percentage of survivors instead "
660  "of their absolute value.")
661 DEFINE_SIZE_T(max_old_space_size, 0, "max size of the old space (in Mbytes)")
662 DEFINE_SIZE_T(initial_old_space_size, 0, "initial old space size (in Mbytes)")
663 DEFINE_BOOL(gc_global, false, "always perform global GCs")
664 DEFINE_INT(random_gc_interval, 0,
665  "Collect garbage after random(0, X) allocations. It overrides "
666  "gc_interval.")
667 DEFINE_INT(gc_interval, -1, "garbage collect after <n> allocations")
668 DEFINE_INT(retain_maps_for_n_gc, 2,
669  "keeps maps alive for <n> old space garbage collections")
670 DEFINE_BOOL(trace_gc, false,
671  "print one trace line following each garbage collection")
672 DEFINE_BOOL(trace_gc_nvp, false,
673  "print one detailed trace line in name=value format "
674  "after each garbage collection")
675 DEFINE_BOOL(trace_gc_ignore_scavenger, false,
676  "do not print trace line after scavenger collection")
677 DEFINE_BOOL(trace_idle_notification, false,
678  "print one trace line following each idle notification")
679 DEFINE_BOOL(trace_idle_notification_verbose, false,
680  "prints the heap state used by the idle notification")
681 DEFINE_BOOL(trace_gc_verbose, false,
682  "print more details following each garbage collection")
683 DEFINE_INT(trace_allocation_stack_interval, -1,
684  "print stack trace after <n> free-list allocations")
685 DEFINE_INT(trace_duplicate_threshold_kb, 0,
686  "print duplicate objects in the heap if their size is more than "
687  "given threshold")
688 DEFINE_BOOL(trace_fragmentation, false, "report fragmentation for old space")
689 DEFINE_BOOL(trace_fragmentation_verbose, false,
690  "report fragmentation for old space (detailed)")
691 DEFINE_BOOL(trace_evacuation, false, "report evacuation statistics")
692 DEFINE_BOOL(trace_mutator_utilization, false,
693  "print mutator utilization, allocation speed, gc speed")
694 DEFINE_BOOL(incremental_marking, true, "use incremental marking")
695 DEFINE_BOOL(incremental_marking_wrappers, true,
696  "use incremental marking for marking wrappers")
697 DEFINE_BOOL(trace_unmapper, false, "Trace the unmapping")
698 DEFINE_BOOL(parallel_scavenge, true, "parallel scavenge")
699 DEFINE_BOOL(trace_parallel_scavenge, false, "trace parallel scavenge")
700 #if defined(V8_TARGET_ARCH_ARM)
701 #define V8_WRITE_PROTECT_CODE_MEMORY_BOOL false
702 #else
703 #define V8_WRITE_PROTECT_CODE_MEMORY_BOOL true
704 #endif
705 DEFINE_BOOL(write_protect_code_memory, V8_WRITE_PROTECT_CODE_MEMORY_BOOL,
706  "write protect code memory")
707 #ifdef V8_CONCURRENT_MARKING
708 #define V8_CONCURRENT_MARKING_BOOL true
709 #else
710 #define V8_CONCURRENT_MARKING_BOOL false
711 #endif
712 DEFINE_BOOL(concurrent_marking, V8_CONCURRENT_MARKING_BOOL,
713  "use concurrent marking")
714 DEFINE_BOOL(parallel_marking, true, "use parallel marking in atomic pause")
715 DEFINE_INT(ephemeron_fixpoint_iterations, 10,
716  "number of fixpoint iterations it takes to switch to linear "
717  "ephemeron algorithm")
718 DEFINE_BOOL(trace_concurrent_marking, false, "trace concurrent marking")
719 DEFINE_BOOL(black_allocation, true, "use black allocation")
720 DEFINE_BOOL(concurrent_store_buffer, true,
721  "use concurrent store buffer processing")
722 DEFINE_BOOL(concurrent_sweeping, true, "use concurrent sweeping")
723 DEFINE_BOOL(parallel_compaction, true, "use parallel compaction")
724 DEFINE_BOOL(parallel_pointer_update, true,
725  "use parallel pointer update during compaction")
726 DEFINE_BOOL(detect_ineffective_gcs_near_heap_limit, true,
727  "trigger out-of-memory failure to avoid GC storm near heap limit")
728 DEFINE_BOOL(trace_incremental_marking, false,
729  "trace progress of the incremental marking")
730 DEFINE_BOOL(trace_stress_marking, false, "trace stress marking progress")
731 DEFINE_BOOL(trace_stress_scavenge, false, "trace stress scavenge progress")
732 DEFINE_BOOL(track_gc_object_stats, false,
733  "track object counts and memory usage")
734 DEFINE_BOOL(trace_gc_object_stats, false,
735  "trace object counts and memory usage")
736 DEFINE_BOOL(trace_zone_stats, false, "trace zone memory usage")
737 DEFINE_BOOL(track_retaining_path, false,
738  "enable support for tracking retaining path")
739 DEFINE_BOOL(concurrent_array_buffer_freeing, true,
740  "free array buffer allocations on a background thread")
741 DEFINE_INT(gc_stats, 0, "Used by tracing internally to enable gc statistics")
742 DEFINE_IMPLICATION(trace_gc_object_stats, track_gc_object_stats)
743 DEFINE_VALUE_IMPLICATION(track_gc_object_stats, gc_stats, 1)
744 DEFINE_VALUE_IMPLICATION(trace_gc_object_stats, gc_stats, 1)
745 DEFINE_NEG_IMPLICATION(trace_gc_object_stats, incremental_marking)
746 DEFINE_NEG_IMPLICATION(track_retaining_path, incremental_marking)
747 DEFINE_NEG_IMPLICATION(track_retaining_path, parallel_marking)
748 DEFINE_NEG_IMPLICATION(track_retaining_path, concurrent_marking)
749 DEFINE_BOOL(track_detached_contexts, true,
750  "track native contexts that are expected to be garbage collected")
751 DEFINE_BOOL(trace_detached_contexts, false,
752  "trace native contexts that are expected to be garbage collected")
753 DEFINE_IMPLICATION(trace_detached_contexts, track_detached_contexts)
754 #ifdef VERIFY_HEAP
755 DEFINE_BOOL(verify_heap, false, "verify heap pointers before and after GC")
756 DEFINE_BOOL(verify_heap_skip_remembered_set, false,
757  "disable remembered set verification")
758 #endif
759 DEFINE_BOOL(move_object_start, true, "enable moving of object starts")
760 DEFINE_BOOL(memory_reducer, true, "use memory reducer")
761 DEFINE_INT(heap_growing_percent, 0,
762  "specifies heap growing factor as (1 + heap_growing_percent/100)")
763 DEFINE_INT(v8_os_page_size, 0, "override OS page size (in KBytes)")
764 DEFINE_BOOL(always_compact, false, "Perform compaction on every full GC")
765 DEFINE_BOOL(never_compact, false,
766  "Never perform compaction on full GC - testing only")
767 DEFINE_BOOL(compact_code_space, true, "Compact code space on full collections")
768 DEFINE_BOOL(use_marking_progress_bar, true,
769  "Use a progress bar to scan large objects in increments when "
770  "incremental marking is active.")
771 DEFINE_BOOL(force_marking_deque_overflows, false,
772  "force overflows of marking deque by reducing it's size "
773  "to 64 words")
774 DEFINE_BOOL(stress_compaction, false,
775  "stress the GC compactor to flush out bugs (implies "
776  "--force_marking_deque_overflows)")
777 DEFINE_BOOL(stress_compaction_random, false,
778  "Stress GC compaction by selecting random percent of pages as "
779  "evacuation candidates. It overrides stress_compaction.")
780 DEFINE_BOOL(stress_incremental_marking, false,
781  "force incremental marking for small heaps and run it more often")
782 
783 DEFINE_BOOL(fuzzer_gc_analysis, false,
784  "prints number of allocations and enables analysis mode for gc "
785  "fuzz testing, e.g. --stress-marking, --stress-scavenge")
786 DEFINE_INT(stress_marking, 0,
787  "force marking at random points between 0 and X (inclusive) percent "
788  "of the regular marking start limit")
789 DEFINE_INT(stress_scavenge, 0,
790  "force scavenge at random points between 0 and X (inclusive) "
791  "percent of the new space capacity")
792 DEFINE_IMPLICATION(fuzzer_gc_analysis, stress_marking)
793 DEFINE_IMPLICATION(fuzzer_gc_analysis, stress_scavenge)
794 
795 DEFINE_BOOL(disable_abortjs, false, "disables AbortJS runtime function")
796 
797 DEFINE_BOOL(manual_evacuation_candidates_selection, false,
798  "Test mode only flag. It allows an unit test to select evacuation "
799  "candidates pages (requires --stress_compaction).")
800 DEFINE_BOOL(fast_promotion_new_space, false,
801  "fast promote new space on high survival rates")
802 
803 DEFINE_BOOL(clear_free_memory, false, "initialize free memory with 0")
804 
805 DEFINE_BOOL(young_generation_large_objects, false,
806  "allocates large objects by default in the young generation large "
807  "object space")
808 
809 DEFINE_BOOL(idle_time_scavenge, true, "Perform scavenges in idle time.")
810 
811 // assembler-ia32.cc / assembler-arm.cc / assembler-x64.cc
812 DEFINE_BOOL(debug_code, DEBUG_BOOL,
813  "generate extra code (assertions) for debugging")
814 DEFINE_BOOL(code_comments, false,
815  "emit comments in code disassembly; for more readable source "
816  "positions you should add --no-concurrent_recompilation")
817 DEFINE_BOOL(enable_sse3, true, "enable use of SSE3 instructions if available")
818 DEFINE_BOOL(enable_ssse3, true, "enable use of SSSE3 instructions if available")
819 DEFINE_BOOL(enable_sse4_1, true,
820  "enable use of SSE4.1 instructions if available")
821 DEFINE_BOOL(enable_sahf, true,
822  "enable use of SAHF instruction if available (X64 only)")
823 DEFINE_BOOL(enable_avx, true, "enable use of AVX instructions if available")
824 DEFINE_BOOL(enable_fma3, true, "enable use of FMA3 instructions if available")
825 DEFINE_BOOL(enable_bmi1, true, "enable use of BMI1 instructions if available")
826 DEFINE_BOOL(enable_bmi2, true, "enable use of BMI2 instructions if available")
827 DEFINE_BOOL(enable_lzcnt, true, "enable use of LZCNT instruction if available")
828 DEFINE_BOOL(enable_popcnt, true,
829  "enable use of POPCNT instruction if available")
830 DEFINE_STRING(arm_arch, ARM_ARCH_DEFAULT,
831  "generate instructions for the selected ARM architecture if "
832  "available: armv6, armv7, armv7+sudiv or armv8")
833 DEFINE_BOOL(force_long_branches, false,
834  "force all emitted branches to be in long mode (MIPS/PPC only)")
835 DEFINE_STRING(mcpu, "auto", "enable optimization for specific cpu")
836 DEFINE_BOOL(partial_constant_pool, true,
837  "enable use of partial constant pools (X64 only)")
838 
839 // Deprecated ARM flags (replaced by arm_arch).
840 DEFINE_MAYBE_BOOL(enable_armv7, "deprecated (use --arm_arch instead)")
841 DEFINE_MAYBE_BOOL(enable_vfp3, "deprecated (use --arm_arch instead)")
842 DEFINE_MAYBE_BOOL(enable_32dregs, "deprecated (use --arm_arch instead)")
843 DEFINE_MAYBE_BOOL(enable_neon, "deprecated (use --arm_arch instead)")
844 DEFINE_MAYBE_BOOL(enable_sudiv, "deprecated (use --arm_arch instead)")
845 DEFINE_MAYBE_BOOL(enable_armv8, "deprecated (use --arm_arch instead)")
846 
847 // regexp-macro-assembler-*.cc
848 DEFINE_BOOL(enable_regexp_unaligned_accesses, true,
849  "enable unaligned accesses for the regexp engine")
850 
851 // api.cc
852 DEFINE_BOOL(script_streaming, true, "enable parsing on background")
853 DEFINE_BOOL(disable_old_api_accessors, false,
854  "Disable old-style API accessors whose setters trigger through the "
855  "prototype chain")
856 
857 // bootstrapper.cc
858 DEFINE_STRING(expose_natives_as, nullptr, "expose natives in global object")
859 DEFINE_BOOL(expose_free_buffer, false, "expose freeBuffer extension")
860 DEFINE_BOOL(expose_gc, false, "expose gc extension")
861 DEFINE_STRING(expose_gc_as, nullptr,
862  "expose gc extension under the specified name")
863 DEFINE_IMPLICATION(expose_gc_as, expose_gc)
864 DEFINE_BOOL(expose_externalize_string, false,
865  "expose externalize string extension")
866 DEFINE_BOOL(expose_trigger_failure, false, "expose trigger-failure extension")
867 DEFINE_INT(stack_trace_limit, 10, "number of stack frames to capture")
868 DEFINE_BOOL(builtins_in_stack_traces, false,
869  "show built-in functions in stack traces")
870 DEFINE_BOOL(disallow_code_generation_from_strings, false,
871  "disallow eval and friends")
872 DEFINE_BOOL(expose_async_hooks, false, "expose async_hooks object")
873 
874 // builtins.cc
875 DEFINE_BOOL(allow_unsafe_function_constructor, false,
876  "allow invoking the function constructor without security checks")
877 DEFINE_BOOL(force_slow_path, false, "always take the slow path for builtins")
878 
879 // builtins-ia32.cc
880 DEFINE_BOOL(inline_new, true, "use fast inline allocation")
881 
882 // codegen-ia32.cc / codegen-arm.cc
883 DEFINE_BOOL(trace, false, "trace function calls")
884 
885 // codegen.cc
886 DEFINE_BOOL(lazy, true, "use lazy compilation")
887 DEFINE_BOOL(trace_opt, false, "trace lazy optimization")
888 DEFINE_BOOL(trace_opt_verbose, false, "extra verbose compilation tracing")
889 DEFINE_IMPLICATION(trace_opt_verbose, trace_opt)
890 DEFINE_BOOL(trace_opt_stats, false, "trace lazy optimization statistics")
891 DEFINE_BOOL(trace_deopt, false, "trace optimize function deoptimization")
892 DEFINE_BOOL(trace_file_names, false,
893  "include file names in trace-opt/trace-deopt output")
894 DEFINE_BOOL(trace_interrupts, false, "trace interrupts when they are handled")
895 DEFINE_BOOL(always_opt, false, "always try to optimize functions")
896 DEFINE_BOOL(always_osr, false, "always try to OSR functions")
897 DEFINE_BOOL(prepare_always_opt, false, "prepare for turning on always opt")
898 
899 DEFINE_BOOL(trace_serializer, false, "print code serializer trace")
900 #ifdef DEBUG
901 DEFINE_BOOL(external_reference_stats, false,
902  "print statistics on external references used during serialization")
903 #endif // DEBUG
904 
905 // compilation-cache.cc
906 DEFINE_BOOL(compilation_cache, true, "enable compilation cache")
907 
908 DEFINE_BOOL(cache_prototype_transitions, true, "cache prototype transitions")
909 
910 // compiler-dispatcher.cc
911 DEFINE_BOOL(parallel_compile_tasks, false, "enable parallel compile tasks")
912 DEFINE_BOOL(compiler_dispatcher, false, "enable compiler dispatcher")
913 DEFINE_IMPLICATION(parallel_compile_tasks, compiler_dispatcher)
914 DEFINE_BOOL(trace_compiler_dispatcher, false,
915  "trace compiler dispatcher activity")
916 
917 // cpu-profiler.cc
918 DEFINE_INT(cpu_profiler_sampling_interval, 1000,
919  "CPU profiler sampling interval in microseconds")
920 
921 // Array abuse tracing
922 DEFINE_BOOL(trace_js_array_abuse, false,
923  "trace out-of-bounds accesses to JS arrays")
924 DEFINE_BOOL(trace_external_array_abuse, false,
925  "trace out-of-bounds-accesses to external arrays")
926 DEFINE_BOOL(trace_array_abuse, false,
927  "trace out-of-bounds accesses to all arrays")
928 DEFINE_IMPLICATION(trace_array_abuse, trace_js_array_abuse)
929 DEFINE_IMPLICATION(trace_array_abuse, trace_external_array_abuse)
930 
931 // debugger
932 DEFINE_BOOL(
933  trace_side_effect_free_debug_evaluate, false,
934  "print debug messages for side-effect-free debug-evaluate for testing")
935 DEFINE_BOOL(hard_abort, true, "abort by crashing")
936 
937 // inspector
938 DEFINE_BOOL(expose_inspector_scripts, false,
939  "expose injected-script-source.js for debugging")
940 
941 // execution.cc
942 DEFINE_INT(stack_size, V8_DEFAULT_STACK_SIZE_KB,
943  "default size of stack region v8 is allowed to use (in kBytes)")
944 
945 // frames.cc
946 DEFINE_INT(max_stack_trace_source_length, 300,
947  "maximum length of function source code printed in a stack trace.")
948 
949 // execution.cc, messages.cc
950 DEFINE_BOOL(clear_exceptions_on_js_entry, false,
951  "clear pending exceptions when entering JavaScript")
952 
953 // counters.cc
954 DEFINE_INT(histogram_interval, 600000,
955  "time interval in ms for aggregating memory histograms")
956 
957 // heap-snapshot-generator.cc
958 DEFINE_BOOL(heap_profiler_trace_objects, false,
959  "Dump heap object allocations/movements/size_updates")
960 DEFINE_BOOL(heap_profiler_use_embedder_graph, true,
961  "Use the new EmbedderGraph API to get embedder nodes")
962 DEFINE_INT(heap_snapshot_string_limit, 1024,
963  "truncate strings to this length in the heap snapshot")
964 
965 // sampling-heap-profiler.cc
966 DEFINE_BOOL(sampling_heap_profiler_suppress_randomness, false,
967  "Use constant sample intervals to eliminate test flakiness")
968 
969 // v8.cc
970 DEFINE_BOOL(use_idle_notification, true,
971  "Use idle notification to reduce memory footprint.")
972 // ic.cc
973 DEFINE_BOOL(trace_ic, false,
974  "trace inline cache state transitions for tools/ic-processor")
975 DEFINE_IMPLICATION(trace_ic, log_code)
976 DEFINE_INT(ic_stats, 0, "inline cache state transitions statistics")
977 DEFINE_VALUE_IMPLICATION(trace_ic, ic_stats, 1)
978 DEFINE_BOOL_READONLY(track_constant_fields, false,
979  "enable constant field tracking")
980 DEFINE_BOOL_READONLY(modify_map_inplace, false, "enable in-place map updates")
981 DEFINE_BOOL_READONLY(fast_map_update, false,
982  "enable fast map update by caching the migration target")
983 
984 // macro-assembler-ia32.cc
985 DEFINE_BOOL(native_code_counters, false,
986  "generate extra code for manipulating stats counters")
987 
988 // objects.cc
989 DEFINE_BOOL(thin_strings, true, "Enable ThinString support")
990 DEFINE_BOOL(trace_prototype_users, false,
991  "Trace updates to prototype user tracking")
992 DEFINE_BOOL(use_verbose_printer, true, "allows verbose printing")
993 DEFINE_BOOL(trace_for_in_enumerate, false, "Trace for-in enumerate slow-paths")
994 DEFINE_BOOL(trace_maps, false, "trace map creation")
995 DEFINE_BOOL(trace_maps_details, true, "also log map details")
996 DEFINE_IMPLICATION(trace_maps, log_code)
997 
998 // parser.cc
999 DEFINE_BOOL(allow_natives_syntax, false, "allow natives syntax")
1000 
1001 // simulator-arm.cc, simulator-arm64.cc and simulator-mips.cc
1002 DEFINE_BOOL(trace_sim, false, "Trace simulator execution")
1003 DEFINE_BOOL(debug_sim, false, "Enable debugging the simulator")
1004 DEFINE_BOOL(check_icache, false,
1005  "Check icache flushes in ARM and MIPS simulator")
1006 DEFINE_INT(stop_sim_at, 0, "Simulator stop after x number of instructions")
1007 #if defined(V8_TARGET_ARCH_ARM64) || defined(V8_TARGET_ARCH_MIPS64) || \
1008  defined(V8_TARGET_ARCH_PPC64)
1009 DEFINE_INT(sim_stack_alignment, 16,
1010  "Stack alignment in bytes in simulator. This must be a power of two "
1011  "and it must be at least 16. 16 is default.")
1012 #else
1013 DEFINE_INT(sim_stack_alignment, 8,
1014  "Stack alingment in bytes in simulator (4 or 8, 8 is default)")
1015 #endif
1016 DEFINE_INT(sim_stack_size, 2 * MB / KB,
1017  "Stack size of the ARM64, MIPS64 and PPC64 simulator "
1018  "in kBytes (default is 2 MB)")
1019 DEFINE_BOOL(log_colour, ENABLE_LOG_COLOUR,
1020  "When logging, try to use coloured output.")
1021 DEFINE_BOOL(ignore_asm_unimplemented_break, false,
1022  "Don't break for ASM_UNIMPLEMENTED_BREAK macros.")
1023 DEFINE_BOOL(trace_sim_messages, false,
1024  "Trace simulator debug messages. Implied by --trace-sim.")
1025 
1026 // isolate.cc
1027 DEFINE_BOOL(async_stack_traces, false,
1028  "include async stack traces in Error.stack")
1029 DEFINE_IMPLICATION(async_stack_traces, harmony_await_optimization)
1030 DEFINE_BOOL(stack_trace_on_illegal, false,
1031  "print stack trace when an illegal exception is thrown")
1032 DEFINE_BOOL(abort_on_uncaught_exception, false,
1033  "abort program (dump core) when an uncaught exception is thrown")
1034 DEFINE_BOOL(abort_on_stack_or_string_length_overflow, false,
1035  "Abort program when the stack overflows or a string exceeds "
1036  "maximum length (as opposed to throwing RangeError). This is "
1037  "useful for fuzzing where the spec behaviour would introduce "
1038  "nondeterminism.")
1039 DEFINE_BOOL(randomize_hashes, true,
1040  "randomize hashes to avoid predictable hash collisions "
1041  "(with snapshots this option cannot override the baked-in seed)")
1042 DEFINE_BOOL(rehash_snapshot, true,
1043  "rehash strings from the snapshot to override the baked-in seed")
1044 DEFINE_UINT64(hash_seed, 0,
1045  "Fixed seed to use to hash property keys (0 means random)"
1046  "(with snapshots this option cannot override the baked-in seed)")
1047 DEFINE_INT(random_seed, 0,
1048  "Default seed for initializing random generator "
1049  "(0, the default, means to use system random).")
1050 DEFINE_INT(fuzzer_random_seed, 0,
1051  "Default seed for initializing fuzzer random generator "
1052  "(0, the default, means to use v8's random number generator seed).")
1053 DEFINE_BOOL(trace_rail, false, "trace RAIL mode")
1054 DEFINE_BOOL(print_all_exceptions, false,
1055  "print exception object and stack trace on each thrown exception")
1056 
1057 // runtime.cc
1058 DEFINE_BOOL(runtime_call_stats, false, "report runtime call counts and times")
1059 DEFINE_INT(runtime_stats, 0,
1060  "internal usage only for controlling runtime statistics")
1061 DEFINE_VALUE_IMPLICATION(runtime_call_stats, runtime_stats, 1)
1062 
1063 // snapshot-common.cc
1064 #ifdef V8_EMBEDDED_BUILTINS
1065 #define V8_EMBEDDED_BUILTINS_BOOL true
1066 #else
1067 #define V8_EMBEDDED_BUILTINS_BOOL false
1068 #endif
1069 DEFINE_BOOL_READONLY(embedded_builtins, V8_EMBEDDED_BUILTINS_BOOL,
1070  "Embed builtin code into the binary.")
1071 DEFINE_BOOL(profile_deserialization, false,
1072  "Print the time it takes to deserialize the snapshot.")
1073 DEFINE_BOOL(serialization_statistics, false,
1074  "Collect statistics on serialized objects.")
1075 DEFINE_UINT(serialization_chunk_size, 4096,
1076  "Custom size for serialization chunks")
1077 
1078 // JIT-less V8. Design doc: goo.gl/kRnhVe
1079 #ifdef V8_JITLESS_MODE
1080 DEFINE_BOOL(jitless, false, "Disable runtime allocation of executable memory.")
1081 #else
1082 DEFINE_BOOL_READONLY(jitless, false,
1083  "Disable runtime allocation of executable memory.")
1084 #endif
1085 
1086 // Regexp
1087 DEFINE_BOOL(regexp_optimization, true, "generate optimized regexp code")
1088 DEFINE_BOOL(regexp_mode_modifiers, false, "enable inline flags in regexp.")
1089 
1090 // Testing flags test/cctest/test-{flags,api,serialization}.cc
1091 DEFINE_BOOL(testing_bool_flag, true, "testing_bool_flag")
1092 DEFINE_MAYBE_BOOL(testing_maybe_bool_flag, "testing_maybe_bool_flag")
1093 DEFINE_INT(testing_int_flag, 13, "testing_int_flag")
1094 DEFINE_FLOAT(testing_float_flag, 2.5, "float-flag")
1095 DEFINE_STRING(testing_string_flag, "Hello, world!", "string-flag")
1096 DEFINE_INT(testing_prng_seed, 42, "Seed used for threading test randomness")
1097 
1098 // mksnapshot.cc
1099 DEFINE_STRING(embedded_src, nullptr,
1100  "Path for the generated embedded data file. (mksnapshot only)")
1101 DEFINE_STRING(
1102  embedded_variant, nullptr,
1103  "Label to disambiguate symbols in embedded data file. (mksnapshot only)")
1104 DEFINE_STRING(startup_src, nullptr,
1105  "Write V8 startup as C++ src. (mksnapshot only)")
1106 DEFINE_STRING(startup_blob, nullptr,
1107  "Write V8 startup blob file. (mksnapshot only)")
1108 
1109 //
1110 // Minor mark compact collector flags.
1111 //
1112 #ifdef ENABLE_MINOR_MC
1113 DEFINE_BOOL(minor_mc_parallel_marking, true,
1114  "use parallel marking for the young generation")
1115 DEFINE_BOOL(trace_minor_mc_parallel_marking, false,
1116  "trace parallel marking for the young generation")
1117 DEFINE_BOOL(minor_mc, false, "perform young generation mark compact GCs")
1118 #endif // ENABLE_MINOR_MC
1119 
1120 //
1121 // Dev shell flags
1122 //
1123 
1124 DEFINE_BOOL(help, false, "Print usage message, including flags, on console")
1125 DEFINE_BOOL(dump_counters, false, "Dump counters on exit")
1126 DEFINE_BOOL(dump_counters_nvp, false,
1127  "Dump counters as name-value pairs on exit")
1128 DEFINE_BOOL(use_external_strings, false, "Use external strings for source code")
1129 
1130 DEFINE_STRING(map_counters, "", "Map counters to a file")
1131 DEFINE_BOOL(mock_arraybuffer_allocator, false,
1132  "Use a mock ArrayBuffer allocator for testing.")
1133 DEFINE_SIZE_T(mock_arraybuffer_allocator_limit, 0,
1134  "Memory limit for mock ArrayBuffer allocator used to simulate "
1135  "OOM for testing.")
1136 
1137 //
1138 // Flags only available in non-Lite modes.
1139 //
1140 #undef FLAG
1141 #ifdef V8_LITE_MODE
1142 #define FLAG FLAG_READONLY
1143 #define V8_LITE_BOOL true
1144 #else
1145 #define FLAG FLAG_FULL
1146 #define V8_LITE_BOOL false
1147 #endif
1148 
1149 // Enable recompilation of function with optimized code.
1150 DEFINE_BOOL(opt, !V8_LITE_BOOL, "use adaptive optimizations")
1151 
1152 // Enable use of inline caches to optimize object access operations.
1153 DEFINE_BOOL(use_ic, !V8_LITE_BOOL, "use inline caching")
1154 
1155 // Favor memory over execution speed.
1156 DEFINE_BOOL(optimize_for_size, V8_LITE_BOOL,
1157  "Enables optimizations which favor memory size over execution "
1158  "speed")
1159 DEFINE_VALUE_IMPLICATION(optimize_for_size, max_semi_space_size, 1)
1160 
1161 //
1162 // GDB JIT integration flags.
1163 //
1164 #undef FLAG
1165 #ifdef ENABLE_GDB_JIT_INTERFACE
1166 #define FLAG FLAG_FULL
1167 #else
1168 #define FLAG FLAG_READONLY
1169 #endif
1170 
1171 DEFINE_BOOL(gdbjit, false, "enable GDBJIT interface")
1172 DEFINE_BOOL(gdbjit_full, false, "enable GDBJIT interface for all code objects")
1173 DEFINE_BOOL(gdbjit_dump, false, "dump elf objects with debug info to disk")
1174 DEFINE_STRING(gdbjit_dump_filter, "",
1175  "dump only objects containing this substring")
1176 
1177 #ifdef ENABLE_GDB_JIT_INTERFACE
1178 DEFINE_IMPLICATION(gdbjit_full, gdbjit)
1179 DEFINE_IMPLICATION(gdbjit_dump, gdbjit)
1180 #endif
1181 DEFINE_NEG_IMPLICATION(gdbjit, compact_code_space)
1182 
1183 //
1184 // Debug only flags
1185 //
1186 #undef FLAG
1187 #ifdef DEBUG
1188 #define FLAG FLAG_FULL
1189 #else
1190 #define FLAG FLAG_READONLY
1191 #endif
1192 
1193 // checks.cc
1194 #ifdef ENABLE_SLOW_DCHECKS
1195 DEFINE_BOOL(enable_slow_asserts, true,
1196  "enable asserts that are slow to execute")
1197 #endif
1198 
1199 // codegen-ia32.cc / codegen-arm.cc / macro-assembler-*.cc
1200 DEFINE_BOOL(print_ast, false, "print source AST")
1201 DEFINE_BOOL(trap_on_abort, false, "replace aborts by breakpoints")
1202 
1203 // compiler.cc
1204 DEFINE_BOOL(print_builtin_scopes, false, "print scopes for builtins")
1205 DEFINE_BOOL(print_scopes, false, "print scopes")
1206 
1207 // contexts.cc
1208 DEFINE_BOOL(trace_contexts, false, "trace contexts operations")
1209 
1210 // heap.cc
1211 DEFINE_BOOL(gc_verbose, false, "print stuff during garbage collection")
1212 DEFINE_BOOL(code_stats, false, "report code statistics after GC")
1213 DEFINE_BOOL(print_handles, false, "report handles after GC")
1214 DEFINE_BOOL(check_handle_count, false,
1215  "Check that there are not too many handles at GC")
1216 DEFINE_BOOL(print_global_handles, false, "report global handles after GC")
1217 
1218 // TurboFan debug-only flags.
1219 DEFINE_BOOL(trace_turbo_escape, false, "enable tracing in escape analysis")
1220 
1221 // objects.cc
1222 DEFINE_BOOL(trace_module_status, false,
1223  "Trace status transitions of ECMAScript modules")
1224 DEFINE_BOOL(trace_normalization, false,
1225  "prints when objects are turned into dictionaries.")
1226 
1227 // runtime.cc
1228 DEFINE_BOOL(trace_lazy, false, "trace lazy compilation")
1229 
1230 // spaces.cc
1231 DEFINE_BOOL(collect_heap_spill_statistics, false,
1232  "report heap spill statistics along with heap_stats "
1233  "(requires heap_stats)")
1234 DEFINE_BOOL(trace_isolates, false, "trace isolate state changes")
1235 
1236 // Regexp
1237 DEFINE_BOOL(regexp_possessive_quantifier, false,
1238  "enable possessive quantifier syntax for testing")
1239 DEFINE_BOOL(trace_regexp_bytecodes, false, "trace regexp bytecode execution")
1240 DEFINE_BOOL(trace_regexp_assembler, false,
1241  "trace regexp macro assembler calls.")
1242 DEFINE_BOOL(trace_regexp_parser, false, "trace regexp parsing")
1243 
1244 // Debugger
1245 DEFINE_BOOL(print_break_location, false, "print source location on debug break")
1246 
1247 // wasm instance management
1248 DEFINE_DEBUG_BOOL(trace_wasm_instances, false,
1249  "trace creation and collection of wasm instances")
1250 
1251 //
1252 // Logging and profiling flags
1253 //
1254 #undef FLAG
1255 #define FLAG FLAG_FULL
1256 
1257 // log.cc
1258 DEFINE_BOOL(log, false,
1259  "Minimal logging (no API, code, GC, suspect, or handles samples).")
1260 DEFINE_BOOL(log_all, false, "Log all events to the log file.")
1261 DEFINE_BOOL(log_api, false, "Log API events to the log file.")
1262 DEFINE_BOOL(log_code, false,
1263  "Log code events to the log file without profiling.")
1264 DEFINE_BOOL(log_handles, false, "Log global handle events.")
1265 DEFINE_BOOL(log_suspect, false, "Log suspect operations.")
1266 DEFINE_BOOL(log_source_code, false, "Log source code.")
1267 DEFINE_BOOL(log_function_events, false,
1268  "Log function events "
1269  "(parse, compile, execute) separately.")
1270 DEFINE_BOOL(prof, false,
1271  "Log statistical profiling information (implies --log-code).")
1272 
1273 DEFINE_BOOL(detailed_line_info, false,
1274  "Always generate detailed line information for CPU profiling.")
1275 
1276 #if defined(ANDROID)
1277 // Phones and tablets have processors that are much slower than desktop
1278 // and laptop computers for which current heuristics are tuned.
1279 #define DEFAULT_PROF_SAMPLING_INTERVAL 5000
1280 #else
1281 #define DEFAULT_PROF_SAMPLING_INTERVAL 1000
1282 #endif
1283 DEFINE_INT(prof_sampling_interval, DEFAULT_PROF_SAMPLING_INTERVAL,
1284  "Interval for --prof samples (in microseconds).")
1285 #undef DEFAULT_PROF_SAMPLING_INTERVAL
1286 
1287 DEFINE_BOOL(prof_cpp, false, "Like --prof, but ignore generated code.")
1288 DEFINE_IMPLICATION(prof, prof_cpp)
1289 DEFINE_BOOL(prof_browser_mode, true,
1290  "Used with --prof, turns on browser-compatible mode for profiling.")
1291 DEFINE_STRING(logfile, "v8.log", "Specify the name of the log file.")
1292 DEFINE_BOOL(logfile_per_isolate, true, "Separate log files for each isolate.")
1293 DEFINE_BOOL(ll_prof, false, "Enable low-level linux profiler.")
1294 DEFINE_BOOL(interpreted_frames_native_stack, false,
1295  "Show interpreted frames on the native stack (useful for external "
1296  "profilers).")
1297 DEFINE_BOOL(perf_basic_prof, false,
1298  "Enable perf linux profiler (basic support).")
1299 DEFINE_NEG_IMPLICATION(perf_basic_prof, compact_code_space)
1300 DEFINE_BOOL(perf_basic_prof_only_functions, false,
1301  "Only report function code ranges to perf (i.e. no stubs).")
1302 DEFINE_IMPLICATION(perf_basic_prof_only_functions, perf_basic_prof)
1303 DEFINE_BOOL(perf_prof, false,
1304  "Enable perf linux profiler (experimental annotate support).")
1305 DEFINE_NEG_IMPLICATION(perf_prof, compact_code_space)
1306 // TODO(v8:8462) Remove implication once perf supports remapping.
1307 DEFINE_NEG_IMPLICATION(perf_prof, write_protect_code_memory)
1308 DEFINE_NEG_IMPLICATION(perf_prof, wasm_write_protect_code_memory)
1309 DEFINE_BOOL(perf_prof_unwinding_info, false,
1310  "Enable unwinding info for perf linux profiler (experimental).")
1311 DEFINE_IMPLICATION(perf_prof, perf_prof_unwinding_info)
1312 DEFINE_STRING(gc_fake_mmap, "/tmp/__v8_gc__",
1313  "Specify the name of the file for fake gc mmap used in ll_prof")
1314 DEFINE_BOOL(log_internal_timer_events, false, "Time internal events.")
1315 DEFINE_BOOL(log_timer_events, false,
1316  "Time events including external callbacks.")
1317 DEFINE_IMPLICATION(log_timer_events, log_internal_timer_events)
1318 DEFINE_IMPLICATION(log_internal_timer_events, prof)
1319 DEFINE_BOOL(log_instruction_stats, false, "Log AArch64 instruction statistics.")
1320 DEFINE_STRING(log_instruction_file, "arm64_inst.csv",
1321  "AArch64 instruction statistics log file.")
1322 DEFINE_INT(log_instruction_period, 1 << 22,
1323  "AArch64 instruction statistics logging period.")
1324 
1325 DEFINE_BOOL(redirect_code_traces, false,
1326  "output deopt information and disassembly into file "
1327  "code-<pid>-<isolate id>.asm")
1328 DEFINE_STRING(redirect_code_traces_to, nullptr,
1329  "output deopt information and disassembly into the given file")
1330 
1331 DEFINE_BOOL(print_opt_source, false,
1332  "print source code of optimized and inlined functions")
1333 
1334 //
1335 // Disassembler only flags
1336 //
1337 #undef FLAG
1338 #ifdef ENABLE_DISASSEMBLER
1339 #define FLAG FLAG_FULL
1340 #else
1341 #define FLAG FLAG_READONLY
1342 #endif
1343 
1344 // elements.cc
1345 DEFINE_BOOL(trace_elements_transitions, false, "trace elements transitions")
1346 
1347 DEFINE_BOOL(trace_creation_allocation_sites, false,
1348  "trace the creation of allocation sites")
1349 
1350 // code-stubs.cc
1351 DEFINE_BOOL(print_code_stubs, false, "print code stubs")
1352 DEFINE_BOOL(test_secondary_stub_cache, false,
1353  "test secondary stub cache by disabling the primary one")
1354 
1355 DEFINE_BOOL(test_primary_stub_cache, false,
1356  "test primary stub cache by disabling the secondary one")
1357 
1358 DEFINE_BOOL(test_small_max_function_context_stub_size, false,
1359  "enable testing the function context size overflow path "
1360  "by making the maximum size smaller")
1361 
1362 // codegen-ia32.cc / codegen-arm.cc
1363 DEFINE_BOOL(print_code, false, "print generated code")
1364 DEFINE_BOOL(print_opt_code, false, "print optimized code")
1365 DEFINE_STRING(print_opt_code_filter, "*", "filter for printing optimized code")
1366 DEFINE_BOOL(print_code_verbose, false, "print more information for code")
1367 DEFINE_BOOL(print_builtin_code, false, "print generated code for builtins")
1368 DEFINE_STRING(print_builtin_code_filter, "*",
1369  "filter for printing builtin code")
1370 DEFINE_BOOL(print_builtin_size, false, "print code size for builtins")
1371 
1372 #ifdef ENABLE_DISASSEMBLER
1373 DEFINE_BOOL(sodium, false,
1374  "print generated code output suitable for use with "
1375  "the Sodium code viewer")
1376 
1377 DEFINE_IMPLICATION(sodium, print_code_stubs)
1378 DEFINE_IMPLICATION(sodium, print_code)
1379 DEFINE_IMPLICATION(sodium, print_opt_code)
1380 DEFINE_IMPLICATION(sodium, code_comments)
1381 
1382 DEFINE_BOOL(print_all_code, false, "enable all flags related to printing code")
1383 DEFINE_IMPLICATION(print_all_code, print_code)
1384 DEFINE_IMPLICATION(print_all_code, print_opt_code)
1385 DEFINE_IMPLICATION(print_all_code, print_code_verbose)
1386 DEFINE_IMPLICATION(print_all_code, print_builtin_code)
1387 DEFINE_IMPLICATION(print_all_code, print_code_stubs)
1388 DEFINE_IMPLICATION(print_all_code, code_comments)
1389 #endif
1390 
1391 #undef FLAG
1392 #define FLAG FLAG_FULL
1393 
1394 //
1395 // Predictable mode related flags.
1396 //
1397 
1398 DEFINE_BOOL(predictable, false, "enable predictable mode")
1399 DEFINE_IMPLICATION(predictable, single_threaded)
1400 DEFINE_NEG_IMPLICATION(predictable, memory_reducer)
1401 DEFINE_VALUE_IMPLICATION(single_threaded, wasm_num_compilation_tasks, 0)
1402 DEFINE_NEG_IMPLICATION(single_threaded, wasm_async_compilation)
1403 
1404 DEFINE_BOOL(predictable_gc_schedule, false,
1405  "Predictable garbage collection schedule. Fixes heap growing, "
1406  "idle, and memory reducing behavior.")
1407 DEFINE_VALUE_IMPLICATION(predictable_gc_schedule, min_semi_space_size, 4)
1408 DEFINE_VALUE_IMPLICATION(predictable_gc_schedule, max_semi_space_size, 4)
1409 DEFINE_VALUE_IMPLICATION(predictable_gc_schedule, heap_growing_percent, 30)
1410 DEFINE_NEG_IMPLICATION(predictable_gc_schedule, idle_time_scavenge)
1411 DEFINE_NEG_IMPLICATION(predictable_gc_schedule, memory_reducer)
1412 
1413 //
1414 // Threading related flags.
1415 //
1416 
1417 DEFINE_BOOL(single_threaded, false, "disable the use of background tasks")
1418 DEFINE_IMPLICATION(single_threaded, single_threaded_gc)
1419 DEFINE_NEG_IMPLICATION(single_threaded, concurrent_recompilation)
1420 DEFINE_NEG_IMPLICATION(single_threaded, compiler_dispatcher)
1421 
1422 //
1423 // Parallel and concurrent GC (Orinoco) related flags.
1424 //
1425 DEFINE_BOOL(single_threaded_gc, false, "disable the use of background gc tasks")
1426 DEFINE_NEG_IMPLICATION(single_threaded_gc, concurrent_marking)
1427 DEFINE_NEG_IMPLICATION(single_threaded_gc, concurrent_sweeping)
1428 DEFINE_NEG_IMPLICATION(single_threaded_gc, parallel_compaction)
1429 DEFINE_NEG_IMPLICATION(single_threaded_gc, parallel_marking)
1430 DEFINE_NEG_IMPLICATION(single_threaded_gc, parallel_pointer_update)
1431 DEFINE_NEG_IMPLICATION(single_threaded_gc, parallel_scavenge)
1432 DEFINE_NEG_IMPLICATION(single_threaded_gc, concurrent_store_buffer)
1433 #ifdef ENABLE_MINOR_MC
1434 DEFINE_NEG_IMPLICATION(single_threaded_gc, minor_mc_parallel_marking)
1435 #endif // ENABLE_MINOR_MC
1436 DEFINE_NEG_IMPLICATION(single_threaded_gc, concurrent_array_buffer_freeing)
1437 
1438 #undef FLAG
1439 
1440 #ifdef VERIFY_PREDICTABLE
1441 #define FLAG FLAG_FULL
1442 #else
1443 #define FLAG FLAG_READONLY
1444 #endif
1445 
1446 DEFINE_BOOL(verify_predictable, false,
1447  "this mode is used for checking that V8 behaves predictably")
1448 DEFINE_INT(dump_allocations_digest_at_alloc, -1,
1449  "dump allocations digest each n-th allocation")
1450 
1451 //
1452 // Read-only flags
1453 //
1454 #undef FLAG
1455 #define FLAG FLAG_READONLY
1456 
1457 // assembler.h
1458 DEFINE_BOOL(enable_embedded_constant_pool, V8_EMBEDDED_CONSTANT_POOL,
1459  "enable use of embedded constant pools (PPC only)")
1460 
1461 DEFINE_BOOL(unbox_double_fields, V8_DOUBLE_FIELDS_UNBOXING,
1462  "enable in-object double fields unboxing (64-bit only)")
1463 DEFINE_IMPLICATION(unbox_double_fields, track_double_fields)
1464 
1465 DEFINE_BOOL(lite_mode, V8_LITE_BOOL,
1466  "enables trade-off of performance for memory savings "
1467  "(Lite mode only)")
1468 
1469 // Cleanup...
1470 #undef FLAG_FULL
1471 #undef FLAG_READONLY
1472 #undef FLAG
1473 #undef FLAG_ALIAS
1474 
1475 #undef DEFINE_BOOL
1476 #undef DEFINE_MAYBE_BOOL
1477 #undef DEFINE_DEBUG_BOOL
1478 #undef DEFINE_INT
1479 #undef DEFINE_STRING
1480 #undef DEFINE_FLOAT
1481 #undef DEFINE_IMPLICATION
1482 #undef DEFINE_NEG_IMPLICATION
1483 #undef DEFINE_NEG_VALUE_IMPLICATION
1484 #undef DEFINE_VALUE_IMPLICATION
1485 #undef DEFINE_ALIAS_BOOL
1486 #undef DEFINE_ALIAS_INT
1487 #undef DEFINE_ALIAS_STRING
1488 #undef DEFINE_ALIAS_FLOAT
1489 
1490 #undef FLAG_MODE_DECLARE
1491 #undef FLAG_MODE_DEFINE
1492 #undef FLAG_MODE_DEFINE_DEFAULTS
1493 #undef FLAG_MODE_META
1494 #undef FLAG_MODE_DEFINE_IMPLICATIONS
1495 
1496 #undef COMMA
Definition: libplatform.h:13
Definition: macros.py:1